// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file // for details. All rights reserved. Use of this source code is governed by a // BSD-style license that can be found in the LICENSE file. #include "vm/regexp.h" #include #include "platform/splay-tree-inl.h" #include "platform/unicode.h" #include "unicode/uniset.h" #include "vm/dart_entry.h" #include "vm/regexp_assembler.h" #include "vm/regexp_assembler_bytecode.h" #include "vm/regexp_assembler_ir.h" #include "vm/regexp_ast.h" #include "vm/symbols.h" #include "vm/thread.h" #include "vm/unibrow-inl.h" #define Z (zone()) namespace dart { // Default to generating optimized regexp code. static const bool kRegexpOptimization = true; // More makes code generation slower, less makes V8 benchmark score lower. static const intptr_t kMaxLookaheadForBoyerMoore = 8; ContainedInLattice AddRange(ContainedInLattice containment, const int32_t* ranges, intptr_t ranges_length, Interval new_range) { ASSERT((ranges_length & 1) == 1); ASSERT(ranges[ranges_length - 1] == Utf::kMaxCodePoint + 1); if (containment == kLatticeUnknown) return containment; bool inside = false; int32_t last = 0; for (intptr_t i = 0; i < ranges_length; inside = !inside, last = ranges[i], i++) { // Consider the range from last to ranges[i]. // We haven't got to the new range yet. if (ranges[i] <= new_range.from()) continue; // New range is wholly inside last-ranges[i]. Note that new_range.to() is // inclusive, but the values in ranges are not. if (last <= new_range.from() && new_range.to() < ranges[i]) { return Combine(containment, inside ? kLatticeIn : kLatticeOut); } return kLatticeUnknown; } return containment; } // ------------------------------------------------------------------- // Implementation of the Irregexp regular expression engine. // // The Irregexp regular expression engine is intended to be a complete // implementation of ECMAScript regular expressions. It generates // IR code that is subsequently compiled to native code. // The Irregexp regexp engine is structured in three steps. // 1) The parser generates an abstract syntax tree. See regexp_ast.cc. // 2) From the AST a node network is created. The nodes are all // subclasses of RegExpNode. The nodes represent states when // executing a regular expression. Several optimizations are // performed on the node network. // 3) From the nodes we generate IR instructions that can actually // execute the regular expression (perform the search). The // code generation step is described in more detail below. // Code generation. // // The nodes are divided into four main categories. // * Choice nodes // These represent places where the regular expression can // match in more than one way. For example on entry to an // alternation (foo|bar) or a repetition (*, +, ? or {}). // * Action nodes // These represent places where some action should be // performed. Examples include recording the current position // in the input string to a register (in order to implement // captures) or other actions on register for example in order // to implement the counters needed for {} repetitions. // * Matching nodes // These attempt to match some element part of the input string. // Examples of elements include character classes, plain strings // or back references. // * End nodes // These are used to implement the actions required on finding // a successful match or failing to find a match. // // The code generated maintains some state as it runs. This consists of the // following elements: // // * The capture registers. Used for string captures. // * Other registers. Used for counters etc. // * The current position. // * The stack of backtracking information. Used when a matching node // fails to find a match and needs to try an alternative. // // Conceptual regular expression execution model: // // There is a simple conceptual model of regular expression execution // which will be presented first. The actual code generated is a more // efficient simulation of the simple conceptual model: // // * Choice nodes are implemented as follows: // For each choice except the last { // push current position // push backtrack code location // // backtrack code location: // pop current position // } // // // * Actions nodes are generated as follows // // // push backtrack code location // // backtrack code location: // // // // * Matching nodes are generated as follows: // if input string matches at current position // update current position // // else // // // Thus it can be seen that the current position is saved and restored // by the choice nodes, whereas the registers are saved and restored by // by the action nodes that manipulate them. // // The other interesting aspect of this model is that nodes are generated // at the point where they are needed by a recursive call to Emit(). If // the node has already been code generated then the Emit() call will // generate a jump to the previously generated code instead. In order to // limit recursion it is possible for the Emit() function to put the node // on a work list for later generation and instead generate a jump. The // destination of the jump is resolved later when the code is generated. // // Actual regular expression code generation. // // Code generation is actually more complicated than the above. In order // to improve the efficiency of the generated code some optimizations are // performed // // * Choice nodes have 1-character lookahead. // A choice node looks at the following character and eliminates some of // the choices immediately based on that character. This is not yet // implemented. // * Simple greedy loops store reduced backtracking information. // A quantifier like /.*foo/m will greedily match the whole input. It will // then need to backtrack to a point where it can match "foo". The naive // implementation of this would push each character position onto the // backtracking stack, then pop them off one by one. This would use space // proportional to the length of the input string. However since the "." // can only match in one way and always has a constant length (in this case // of 1) it suffices to store the current position on the top of the stack // once. Matching now becomes merely incrementing the current position and // backtracking becomes decrementing the current position and checking the // result against the stored current position. This is faster and saves // space. // * The current state is virtualized. // This is used to defer expensive operations until it is clear that they // are needed and to generate code for a node more than once, allowing // specialized an efficient versions of the code to be created. This is // explained in the section below. // // Execution state virtualization. // // Instead of emitting code, nodes that manipulate the state can record their // manipulation in an object called the Trace. The Trace object can record a // current position offset, an optional backtrack code location on the top of // the virtualized backtrack stack and some register changes. When a node is // to be emitted it can flush the Trace or update it. Flushing the Trace // will emit code to bring the actual state into line with the virtual state. // Avoiding flushing the state can postpone some work (e.g. updates of capture // registers). Postponing work can save time when executing the regular // expression since it may be found that the work never has to be done as a // failure to match can occur. In addition it is much faster to jump to a // known backtrack code location than it is to pop an unknown backtrack // location from the stack and jump there. // // The virtual state found in the Trace affects code generation. For example // the virtual state contains the difference between the actual current // position and the virtual current position, and matching code needs to use // this offset to attempt a match in the correct location of the input // string. Therefore code generated for a non-trivial trace is specialized // to that trace. The code generator therefore has the ability to generate // code for each node several times. In order to limit the size of the // generated code there is an arbitrary limit on how many specialized sets of // code may be generated for a given node. If the limit is reached, the // trace is flushed and a generic version of the code for a node is emitted. // This is subsequently used for that node. The code emitted for non-generic // trace is not recorded in the node and so it cannot currently be reused in // the event that code generation is requested for an identical trace. void RegExpTree::AppendToText(RegExpText* text) { UNREACHABLE(); } void RegExpAtom::AppendToText(RegExpText* text) { text->AddElement(TextElement::Atom(this)); } void RegExpCharacterClass::AppendToText(RegExpText* text) { text->AddElement(TextElement::CharClass(this)); } void RegExpText::AppendToText(RegExpText* text) { for (intptr_t i = 0; i < elements()->length(); i++) text->AddElement((*elements())[i]); } TextElement TextElement::Atom(RegExpAtom* atom) { return TextElement(ATOM, atom); } TextElement TextElement::CharClass(RegExpCharacterClass* char_class) { return TextElement(CHAR_CLASS, char_class); } intptr_t TextElement::length() const { switch (text_type()) { case ATOM: return atom()->length(); case CHAR_CLASS: return 1; } UNREACHABLE(); return 0; } class FrequencyCollator : public ValueObject { public: FrequencyCollator() : total_samples_(0) { for (intptr_t i = 0; i < RegExpMacroAssembler::kTableSize; i++) { frequencies_[i] = CharacterFrequency(i); } } void CountCharacter(intptr_t character) { intptr_t index = (character & RegExpMacroAssembler::kTableMask); frequencies_[index].Increment(); total_samples_++; } // Does not measure in percent, but rather per-128 (the table size from the // regexp macro assembler). intptr_t Frequency(intptr_t in_character) { ASSERT((in_character & RegExpMacroAssembler::kTableMask) == in_character); if (total_samples_ < 1) return 1; // Division by zero. intptr_t freq_in_per128 = (frequencies_[in_character].counter() * 128) / total_samples_; return freq_in_per128; } private: class CharacterFrequency { public: CharacterFrequency() : counter_(0), character_(-1) {} explicit CharacterFrequency(intptr_t character) : counter_(0), character_(character) {} void Increment() { counter_++; } intptr_t counter() { return counter_; } intptr_t character() { return character_; } private: intptr_t counter_; intptr_t character_; DISALLOW_ALLOCATION(); }; private: CharacterFrequency frequencies_[RegExpMacroAssembler::kTableSize]; intptr_t total_samples_; }; class RegExpCompiler : public ValueObject { public: RegExpCompiler(intptr_t capture_count, bool is_one_byte); intptr_t AllocateRegister() { return next_register_++; } // Lookarounds to match lone surrogates for unicode character class matches // are never nested. We can therefore reuse registers. intptr_t UnicodeLookaroundStackRegister() { if (unicode_lookaround_stack_register_ == kNoRegister) { unicode_lookaround_stack_register_ = AllocateRegister(); } return unicode_lookaround_stack_register_; } intptr_t UnicodeLookaroundPositionRegister() { if (unicode_lookaround_position_register_ == kNoRegister) { unicode_lookaround_position_register_ = AllocateRegister(); } return unicode_lookaround_position_register_; } #if !defined(DART_PRECOMPILED_RUNTIME) RegExpEngine::CompilationResult Assemble(IRRegExpMacroAssembler* assembler, RegExpNode* start, intptr_t capture_count, const String& pattern); #endif RegExpEngine::CompilationResult Assemble( BytecodeRegExpMacroAssembler* assembler, RegExpNode* start, intptr_t capture_count, const String& pattern); inline void AddWork(RegExpNode* node) { work_list_->Add(node); } static const intptr_t kImplementationOffset = 0; static const intptr_t kNumberOfRegistersOffset = 0; static const intptr_t kCodeOffset = 1; RegExpMacroAssembler* macro_assembler() { return macro_assembler_; } EndNode* accept() { return accept_; } static const intptr_t kMaxRecursion = 100; inline intptr_t recursion_depth() { return recursion_depth_; } inline void IncrementRecursionDepth() { recursion_depth_++; } inline void DecrementRecursionDepth() { recursion_depth_--; } void SetRegExpTooBig() { reg_exp_too_big_ = true; } inline bool one_byte() const { return is_one_byte_; } bool read_backward() { return read_backward_; } void set_read_backward(bool value) { read_backward_ = value; } FrequencyCollator* frequency_collator() { return &frequency_collator_; } intptr_t current_expansion_factor() { return current_expansion_factor_; } void set_current_expansion_factor(intptr_t value) { current_expansion_factor_ = value; } Zone* zone() const { return zone_; } static const intptr_t kNoRegister = -1; private: EndNode* accept_; intptr_t next_register_; intptr_t unicode_lookaround_stack_register_; intptr_t unicode_lookaround_position_register_; ZoneGrowableArray* work_list_; intptr_t recursion_depth_; RegExpMacroAssembler* macro_assembler_; bool is_one_byte_; bool reg_exp_too_big_; bool read_backward_; intptr_t current_expansion_factor_; FrequencyCollator frequency_collator_; Zone* zone_; }; class RecursionCheck : public ValueObject { public: explicit RecursionCheck(RegExpCompiler* compiler) : compiler_(compiler) { compiler->IncrementRecursionDepth(); } ~RecursionCheck() { compiler_->DecrementRecursionDepth(); } private: RegExpCompiler* compiler_; }; static RegExpEngine::CompilationResult IrregexpRegExpTooBig() { return RegExpEngine::CompilationResult("RegExp too big"); } // Attempts to compile the regexp using an Irregexp code generator. Returns // a fixed array or a null handle depending on whether it succeeded. RegExpCompiler::RegExpCompiler(intptr_t capture_count, bool is_one_byte) : next_register_(2 * (capture_count + 1)), unicode_lookaround_stack_register_(kNoRegister), unicode_lookaround_position_register_(kNoRegister), work_list_(NULL), recursion_depth_(0), is_one_byte_(is_one_byte), reg_exp_too_big_(false), read_backward_(false), current_expansion_factor_(1), zone_(Thread::Current()->zone()) { accept_ = new (Z) EndNode(EndNode::ACCEPT, Z); } #if !defined(DART_PRECOMPILED_RUNTIME) RegExpEngine::CompilationResult RegExpCompiler::Assemble( IRRegExpMacroAssembler* macro_assembler, RegExpNode* start, intptr_t capture_count, const String& pattern) { macro_assembler->set_slow_safe(false /* use_slow_safe_regexp_compiler */); macro_assembler_ = macro_assembler; ZoneGrowableArray work_list(0); work_list_ = &work_list; BlockLabel fail; macro_assembler_->PushBacktrack(&fail); Trace new_trace; start->Emit(this, &new_trace); macro_assembler_->BindBlock(&fail); macro_assembler_->Fail(); while (!work_list.is_empty()) { work_list.RemoveLast()->Emit(this, &new_trace); } if (reg_exp_too_big_) return IrregexpRegExpTooBig(); macro_assembler->GenerateBacktrackBlock(); macro_assembler->FinalizeRegistersArray(); return RegExpEngine::CompilationResult( macro_assembler->backtrack_goto(), macro_assembler->graph_entry(), macro_assembler->num_blocks(), macro_assembler->num_stack_locals(), next_register_); } #endif RegExpEngine::CompilationResult RegExpCompiler::Assemble( BytecodeRegExpMacroAssembler* macro_assembler, RegExpNode* start, intptr_t capture_count, const String& pattern) { macro_assembler->set_slow_safe(false /* use_slow_safe_regexp_compiler */); macro_assembler_ = macro_assembler; ZoneGrowableArray work_list(0); work_list_ = &work_list; BlockLabel fail; macro_assembler_->PushBacktrack(&fail); Trace new_trace; start->Emit(this, &new_trace); macro_assembler_->BindBlock(&fail); macro_assembler_->Fail(); while (!work_list.is_empty()) { work_list.RemoveLast()->Emit(this, &new_trace); } if (reg_exp_too_big_) return IrregexpRegExpTooBig(); TypedData& bytecode = TypedData::ZoneHandle(macro_assembler->GetBytecode()); return RegExpEngine::CompilationResult(&bytecode, next_register_); } bool Trace::DeferredAction::Mentions(intptr_t that) { if (action_type() == ActionNode::CLEAR_CAPTURES) { Interval range = static_cast(this)->range(); return range.Contains(that); } else { return reg() == that; } } bool Trace::mentions_reg(intptr_t reg) { for (DeferredAction* action = actions_; action != NULL; action = action->next()) { if (action->Mentions(reg)) return true; } return false; } bool Trace::GetStoredPosition(intptr_t reg, intptr_t* cp_offset) { ASSERT(*cp_offset == 0); for (DeferredAction* action = actions_; action != NULL; action = action->next()) { if (action->Mentions(reg)) { if (action->action_type() == ActionNode::STORE_POSITION) { *cp_offset = static_cast(action)->cp_offset(); return true; } else { return false; } } } return false; } // This is called as we come into a loop choice node and some other tricky // nodes. It normalizes the state of the code generator to ensure we can // generate generic code. intptr_t Trace::FindAffectedRegisters(OutSet* affected_registers, Zone* zone) { intptr_t max_register = RegExpCompiler::kNoRegister; for (DeferredAction* action = actions_; action != NULL; action = action->next()) { if (action->action_type() == ActionNode::CLEAR_CAPTURES) { Interval range = static_cast(action)->range(); for (intptr_t i = range.from(); i <= range.to(); i++) affected_registers->Set(i, zone); if (range.to() > max_register) max_register = range.to(); } else { affected_registers->Set(action->reg(), zone); if (action->reg() > max_register) max_register = action->reg(); } } return max_register; } void Trace::RestoreAffectedRegisters(RegExpMacroAssembler* assembler, intptr_t max_register, const OutSet& registers_to_pop, const OutSet& registers_to_clear) { for (intptr_t reg = max_register; reg >= 0; reg--) { if (registers_to_pop.Get(reg)) { assembler->PopRegister(reg); } else if (registers_to_clear.Get(reg)) { intptr_t clear_to = reg; while (reg > 0 && registers_to_clear.Get(reg - 1)) { reg--; } assembler->ClearRegisters(reg, clear_to); } } } void Trace::PerformDeferredActions(RegExpMacroAssembler* assembler, intptr_t max_register, const OutSet& affected_registers, OutSet* registers_to_pop, OutSet* registers_to_clear, Zone* zone) { for (intptr_t reg = 0; reg <= max_register; reg++) { if (!affected_registers.Get(reg)) { continue; } // The chronologically first deferred action in the trace // is used to infer the action needed to restore a register // to its previous state (or not, if it's safe to ignore it). enum DeferredActionUndoType { ACTION_IGNORE, ACTION_RESTORE, ACTION_CLEAR }; DeferredActionUndoType undo_action = ACTION_IGNORE; intptr_t value = 0; bool absolute = false; bool clear = false; static const intptr_t kNoStore = kMinInt32; intptr_t store_position = kNoStore; // This is a little tricky because we are scanning the actions in reverse // historical order (newest first). for (DeferredAction* action = actions_; action != NULL; action = action->next()) { if (action->Mentions(reg)) { switch (action->action_type()) { case ActionNode::SET_REGISTER: { Trace::DeferredSetRegister* psr = static_cast(action); if (!absolute) { value += psr->value(); absolute = true; } // SET_REGISTER is currently only used for newly introduced loop // counters. They can have a significant previous value if they // occour in a loop. TODO(lrn): Propagate this information, so we // can set undo_action to ACTION_IGNORE if we know there is no // value to restore. undo_action = ACTION_RESTORE; ASSERT(store_position == kNoStore); ASSERT(!clear); break; } case ActionNode::INCREMENT_REGISTER: if (!absolute) { value++; } ASSERT(store_position == kNoStore); ASSERT(!clear); undo_action = ACTION_RESTORE; break; case ActionNode::STORE_POSITION: { Trace::DeferredCapture* pc = static_cast(action); if (!clear && store_position == kNoStore) { store_position = pc->cp_offset(); } // For captures we know that stores and clears alternate. // Other register, are never cleared, and if the occur // inside a loop, they might be assigned more than once. if (reg <= 1) { // Registers zero and one, aka "capture zero", is // always set correctly if we succeed. There is no // need to undo a setting on backtrack, because we // will set it again or fail. undo_action = ACTION_IGNORE; } else { undo_action = pc->is_capture() ? ACTION_CLEAR : ACTION_RESTORE; } ASSERT(!absolute); ASSERT(value == 0); break; } case ActionNode::CLEAR_CAPTURES: { // Since we're scanning in reverse order, if we've already // set the position we have to ignore historically earlier // clearing operations. if (store_position == kNoStore) { clear = true; } undo_action = ACTION_RESTORE; ASSERT(!absolute); ASSERT(value == 0); break; } default: UNREACHABLE(); break; } } } // Prepare for the undo-action (e.g., push if it's going to be popped). if (undo_action == ACTION_RESTORE) { assembler->PushRegister(reg); registers_to_pop->Set(reg, zone); } else if (undo_action == ACTION_CLEAR) { registers_to_clear->Set(reg, zone); } // Perform the chronologically last action (or accumulated increment) // for the register. if (store_position != kNoStore) { assembler->WriteCurrentPositionToRegister(reg, store_position); } else if (clear) { assembler->ClearRegisters(reg, reg); } else if (absolute) { assembler->SetRegister(reg, value); } else if (value != 0) { assembler->AdvanceRegister(reg, value); } } } // This is called as we come into a loop choice node and some other tricky // nodes. It normalizes the state of the code generator to ensure we can // generate generic code. void Trace::Flush(RegExpCompiler* compiler, RegExpNode* successor) { RegExpMacroAssembler* assembler = compiler->macro_assembler(); ASSERT(!is_trivial()); if (actions_ == NULL && backtrack() == NULL) { // Here we just have some deferred cp advances to fix and we are back to // a normal situation. We may also have to forget some information gained // through a quick check that was already performed. if (cp_offset_ != 0) assembler->AdvanceCurrentPosition(cp_offset_); // Create a new trivial state and generate the node with that. Trace new_state; successor->Emit(compiler, &new_state); return; } // Generate deferred actions here along with code to undo them again. OutSet affected_registers; if (backtrack() != NULL) { // Here we have a concrete backtrack location. These are set up by choice // nodes and so they indicate that we have a deferred save of the current // position which we may need to emit here. assembler->PushCurrentPosition(); } Zone* zone = successor->zone(); intptr_t max_register = FindAffectedRegisters(&affected_registers, zone); OutSet registers_to_pop; OutSet registers_to_clear; PerformDeferredActions(assembler, max_register, affected_registers, ®isters_to_pop, ®isters_to_clear, zone); if (cp_offset_ != 0) { assembler->AdvanceCurrentPosition(cp_offset_); } // Create a new trivial state and generate the node with that. BlockLabel undo; assembler->PushBacktrack(&undo); Trace new_state; successor->Emit(compiler, &new_state); // On backtrack we need to restore state. assembler->BindBlock(&undo); RestoreAffectedRegisters(assembler, max_register, registers_to_pop, registers_to_clear); if (backtrack() == NULL) { assembler->Backtrack(); } else { assembler->PopCurrentPosition(); assembler->GoTo(backtrack()); } } void NegativeSubmatchSuccess::Emit(RegExpCompiler* compiler, Trace* trace) { RegExpMacroAssembler* assembler = compiler->macro_assembler(); // Omit flushing the trace. We discard the entire stack frame anyway. if (!label()->IsBound()) { // We are completely independent of the trace, since we ignore it, // so this code can be used as the generic version. assembler->BindBlock(label()); } // Throw away everything on the backtrack stack since the start // of the negative submatch and restore the character position. assembler->ReadCurrentPositionFromRegister(current_position_register_); assembler->ReadStackPointerFromRegister(stack_pointer_register_); if (clear_capture_count_ > 0) { // Clear any captures that might have been performed during the success // of the body of the negative look-ahead. int clear_capture_end = clear_capture_start_ + clear_capture_count_ - 1; assembler->ClearRegisters(clear_capture_start_, clear_capture_end); } // Now that we have unwound the stack we find at the top of the stack the // backtrack that the BeginSubmatch node got. assembler->Backtrack(); } void EndNode::Emit(RegExpCompiler* compiler, Trace* trace) { if (!trace->is_trivial()) { trace->Flush(compiler, this); return; } RegExpMacroAssembler* assembler = compiler->macro_assembler(); if (!label()->IsBound()) { assembler->BindBlock(label()); } switch (action_) { case ACCEPT: assembler->Succeed(); return; case BACKTRACK: assembler->GoTo(trace->backtrack()); return; case NEGATIVE_SUBMATCH_SUCCESS: // This case is handled in a different virtual method. UNREACHABLE(); } UNIMPLEMENTED(); } void GuardedAlternative::AddGuard(Guard* guard, Zone* zone) { if (guards_ == NULL) guards_ = new (zone) ZoneGrowableArray(1); guards_->Add(guard); } ActionNode* ActionNode::SetRegister(intptr_t reg, intptr_t val, RegExpNode* on_success) { ActionNode* result = new (on_success->zone()) ActionNode(SET_REGISTER, on_success); result->data_.u_store_register.reg = reg; result->data_.u_store_register.value = val; return result; } ActionNode* ActionNode::IncrementRegister(intptr_t reg, RegExpNode* on_success) { ActionNode* result = new (on_success->zone()) ActionNode(INCREMENT_REGISTER, on_success); result->data_.u_increment_register.reg = reg; return result; } ActionNode* ActionNode::StorePosition(intptr_t reg, bool is_capture, RegExpNode* on_success) { ActionNode* result = new (on_success->zone()) ActionNode(STORE_POSITION, on_success); result->data_.u_position_register.reg = reg; result->data_.u_position_register.is_capture = is_capture; return result; } ActionNode* ActionNode::ClearCaptures(Interval range, RegExpNode* on_success) { ActionNode* result = new (on_success->zone()) ActionNode(CLEAR_CAPTURES, on_success); result->data_.u_clear_captures.range_from = range.from(); result->data_.u_clear_captures.range_to = range.to(); return result; } ActionNode* ActionNode::BeginSubmatch(intptr_t stack_reg, intptr_t position_reg, RegExpNode* on_success) { ActionNode* result = new (on_success->zone()) ActionNode(BEGIN_SUBMATCH, on_success); result->data_.u_submatch.stack_pointer_register = stack_reg; result->data_.u_submatch.current_position_register = position_reg; return result; } ActionNode* ActionNode::PositiveSubmatchSuccess(intptr_t stack_reg, intptr_t position_reg, intptr_t clear_register_count, intptr_t clear_register_from, RegExpNode* on_success) { ActionNode* result = new (on_success->zone()) ActionNode(POSITIVE_SUBMATCH_SUCCESS, on_success); result->data_.u_submatch.stack_pointer_register = stack_reg; result->data_.u_submatch.current_position_register = position_reg; result->data_.u_submatch.clear_register_count = clear_register_count; result->data_.u_submatch.clear_register_from = clear_register_from; return result; } ActionNode* ActionNode::EmptyMatchCheck(intptr_t start_register, intptr_t repetition_register, intptr_t repetition_limit, RegExpNode* on_success) { ActionNode* result = new (on_success->zone()) ActionNode(EMPTY_MATCH_CHECK, on_success); result->data_.u_empty_match_check.start_register = start_register; result->data_.u_empty_match_check.repetition_register = repetition_register; result->data_.u_empty_match_check.repetition_limit = repetition_limit; return result; } #define DEFINE_ACCEPT(Type) \ void Type##Node::Accept(NodeVisitor* visitor) { visitor->Visit##Type(this); } FOR_EACH_NODE_TYPE(DEFINE_ACCEPT) #undef DEFINE_ACCEPT void LoopChoiceNode::Accept(NodeVisitor* visitor) { visitor->VisitLoopChoice(this); } // ------------------------------------------------------------------- // Emit code. void ChoiceNode::GenerateGuard(RegExpMacroAssembler* macro_assembler, Guard* guard, Trace* trace) { switch (guard->op()) { case Guard::LT: ASSERT(!trace->mentions_reg(guard->reg())); macro_assembler->IfRegisterGE(guard->reg(), guard->value(), trace->backtrack()); break; case Guard::GEQ: ASSERT(!trace->mentions_reg(guard->reg())); macro_assembler->IfRegisterLT(guard->reg(), guard->value(), trace->backtrack()); break; } } // Returns the number of characters in the equivalence class, omitting those // that cannot occur in the source string because it is ASCII. static intptr_t GetCaseIndependentLetters(uint16_t character, bool one_byte_subject, int32_t* letters) { unibrow::Mapping jsregexp_uncanonicalize; intptr_t length = jsregexp_uncanonicalize.get(character, '\0', letters); // Unibrow returns 0 or 1 for characters where case independence is // trivial. if (length == 0) { letters[0] = character; length = 1; } if (!one_byte_subject || character <= Symbols::kMaxOneCharCodeSymbol) { return length; } // The standard requires that non-ASCII characters cannot have ASCII // character codes in their equivalence class. // TODO(dcarney): issue 3550 this is not actually true for Latin1 anymore, // is it? For example, \u00C5 is equivalent to \u212B. return 0; } static inline bool EmitSimpleCharacter(Zone* zone, RegExpCompiler* compiler, uint16_t c, BlockLabel* on_failure, intptr_t cp_offset, bool check, bool preloaded) { RegExpMacroAssembler* assembler = compiler->macro_assembler(); bool bound_checked = false; if (!preloaded) { assembler->LoadCurrentCharacter(cp_offset, on_failure, check); bound_checked = true; } assembler->CheckNotCharacter(c, on_failure); return bound_checked; } // Only emits non-letters (things that don't have case). Only used for case // independent matches. static inline bool EmitAtomNonLetter(Zone* zone, RegExpCompiler* compiler, uint16_t c, BlockLabel* on_failure, intptr_t cp_offset, bool check, bool preloaded) { RegExpMacroAssembler* macro_assembler = compiler->macro_assembler(); bool one_byte = compiler->one_byte(); int32_t chars[unibrow::Ecma262UnCanonicalize::kMaxWidth]; intptr_t length = GetCaseIndependentLetters(c, one_byte, chars); if (length < 1) { // This can't match. Must be an one-byte subject and a non-one-byte // character. We do not need to do anything since the one-byte pass // already handled this. return false; // Bounds not checked. } bool checked = false; // We handle the length > 1 case in a later pass. if (length == 1) { if (one_byte && c > Symbols::kMaxOneCharCodeSymbol) { // Can't match - see above. return false; // Bounds not checked. } if (!preloaded) { macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check); checked = check; } macro_assembler->CheckNotCharacter(c, on_failure); } return checked; } static bool ShortCutEmitCharacterPair(RegExpMacroAssembler* macro_assembler, bool one_byte, uint16_t c1, uint16_t c2, BlockLabel* on_failure) { uint16_t char_mask; if (one_byte) { char_mask = Symbols::kMaxOneCharCodeSymbol; } else { char_mask = Utf16::kMaxCodeUnit; } uint16_t exor = c1 ^ c2; // Check whether exor has only one bit set. if (((exor - 1) & exor) == 0) { // If c1 and c2 differ only by one bit. // Ecma262UnCanonicalize always gives the highest number last. ASSERT(c2 > c1); uint16_t mask = char_mask ^ exor; macro_assembler->CheckNotCharacterAfterAnd(c1, mask, on_failure); return true; } ASSERT(c2 > c1); uint16_t diff = c2 - c1; if (((diff - 1) & diff) == 0 && c1 >= diff) { // If the characters differ by 2^n but don't differ by one bit then // subtract the difference from the found character, then do the or // trick. We avoid the theoretical case where negative numbers are // involved in order to simplify code generation. uint16_t mask = char_mask ^ diff; macro_assembler->CheckNotCharacterAfterMinusAnd(c1 - diff, diff, mask, on_failure); return true; } return false; } typedef bool EmitCharacterFunction(Zone* zone, RegExpCompiler* compiler, uint16_t c, BlockLabel* on_failure, intptr_t cp_offset, bool check, bool preloaded); // Only emits letters (things that have case). Only used for case independent // matches. static inline bool EmitAtomLetter(Zone* zone, RegExpCompiler* compiler, uint16_t c, BlockLabel* on_failure, intptr_t cp_offset, bool check, bool preloaded) { RegExpMacroAssembler* macro_assembler = compiler->macro_assembler(); bool one_byte = compiler->one_byte(); int32_t chars[unibrow::Ecma262UnCanonicalize::kMaxWidth]; intptr_t length = GetCaseIndependentLetters(c, one_byte, chars); if (length <= 1) return false; // We may not need to check against the end of the input string // if this character lies before a character that matched. if (!preloaded) { macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check); } BlockLabel ok; ASSERT(unibrow::Ecma262UnCanonicalize::kMaxWidth == 4); switch (length) { case 2: { if (ShortCutEmitCharacterPair(macro_assembler, one_byte, chars[0], chars[1], on_failure)) { } else { macro_assembler->CheckCharacter(chars[0], &ok); macro_assembler->CheckNotCharacter(chars[1], on_failure); macro_assembler->BindBlock(&ok); } break; } case 4: macro_assembler->CheckCharacter(chars[3], &ok); FALL_THROUGH; case 3: macro_assembler->CheckCharacter(chars[0], &ok); macro_assembler->CheckCharacter(chars[1], &ok); macro_assembler->CheckNotCharacter(chars[2], on_failure); macro_assembler->BindBlock(&ok); break; default: UNREACHABLE(); break; } return true; } static void EmitBoundaryTest(RegExpMacroAssembler* masm, uint16_t border, BlockLabel* fall_through, BlockLabel* above_or_equal, BlockLabel* below) { if (below != fall_through) { masm->CheckCharacterLT(border, below); if (above_or_equal != fall_through) masm->GoTo(above_or_equal); } else { masm->CheckCharacterGT(border - 1, above_or_equal); } } static void EmitDoubleBoundaryTest(RegExpMacroAssembler* masm, uint16_t first, uint16_t last, BlockLabel* fall_through, BlockLabel* in_range, BlockLabel* out_of_range) { if (in_range == fall_through) { if (first == last) { masm->CheckNotCharacter(first, out_of_range); } else { masm->CheckCharacterNotInRange(first, last, out_of_range); } } else { if (first == last) { masm->CheckCharacter(first, in_range); } else { masm->CheckCharacterInRange(first, last, in_range); } if (out_of_range != fall_through) masm->GoTo(out_of_range); } } // even_label is for ranges[i] to ranges[i + 1] where i - start_index is even. // odd_label is for ranges[i] to ranges[i + 1] where i - start_index is odd. static void EmitUseLookupTable(RegExpMacroAssembler* masm, ZoneGrowableArray* ranges, intptr_t start_index, intptr_t end_index, uint16_t min_char, BlockLabel* fall_through, BlockLabel* even_label, BlockLabel* odd_label) { static const intptr_t kSize = RegExpMacroAssembler::kTableSize; static const intptr_t kMask = RegExpMacroAssembler::kTableMask; intptr_t base = (min_char & ~kMask); // Assert that everything is on one kTableSize page. for (intptr_t i = start_index; i <= end_index; i++) { ASSERT((ranges->At(i) & ~kMask) == base); } ASSERT(start_index == 0 || (ranges->At(start_index - 1) & ~kMask) <= base); char templ[kSize]; BlockLabel* on_bit_set; BlockLabel* on_bit_clear; intptr_t bit; if (even_label == fall_through) { on_bit_set = odd_label; on_bit_clear = even_label; bit = 1; } else { on_bit_set = even_label; on_bit_clear = odd_label; bit = 0; } for (intptr_t i = 0; i < (ranges->At(start_index) & kMask) && i < kSize; i++) { templ[i] = bit; } intptr_t j = 0; bit ^= 1; for (intptr_t i = start_index; i < end_index; i++) { for (j = (ranges->At(i) & kMask); j < (ranges->At(i + 1) & kMask); j++) { templ[j] = bit; } bit ^= 1; } for (intptr_t i = j; i < kSize; i++) { templ[i] = bit; } // TODO(erikcorry): Cache these. const TypedData& ba = TypedData::ZoneHandle( masm->zone(), TypedData::New(kTypedDataUint8ArrayCid, kSize, Heap::kOld)); for (intptr_t i = 0; i < kSize; i++) { ba.SetUint8(i, templ[i]); } masm->CheckBitInTable(ba, on_bit_set); if (on_bit_clear != fall_through) masm->GoTo(on_bit_clear); } static void CutOutRange(RegExpMacroAssembler* masm, ZoneGrowableArray* ranges, intptr_t start_index, intptr_t end_index, intptr_t cut_index, BlockLabel* even_label, BlockLabel* odd_label) { bool odd = (((cut_index - start_index) & 1) == 1); BlockLabel* in_range_label = odd ? odd_label : even_label; BlockLabel dummy; EmitDoubleBoundaryTest(masm, ranges->At(cut_index), ranges->At(cut_index + 1) - 1, &dummy, in_range_label, &dummy); ASSERT(!dummy.IsLinked()); // Cut out the single range by rewriting the array. This creates a new // range that is a merger of the two ranges on either side of the one we // are cutting out. The oddity of the labels is preserved. for (intptr_t j = cut_index; j > start_index; j--) { (*ranges)[j] = ranges->At(j - 1); } for (intptr_t j = cut_index + 1; j < end_index; j++) { (*ranges)[j] = ranges->At(j + 1); } } // Unicode case. Split the search space into kSize spaces that are handled // with recursion. static void SplitSearchSpace(ZoneGrowableArray* ranges, intptr_t start_index, intptr_t end_index, intptr_t* new_start_index, intptr_t* new_end_index, uint16_t* border) { static const intptr_t kSize = RegExpMacroAssembler::kTableSize; static const intptr_t kMask = RegExpMacroAssembler::kTableMask; uint16_t first = ranges->At(start_index); uint16_t last = ranges->At(end_index) - 1; *new_start_index = start_index; *border = (ranges->At(start_index) & ~kMask) + kSize; while (*new_start_index < end_index) { if (ranges->At(*new_start_index) > *border) break; (*new_start_index)++; } // new_start_index is the index of the first edge that is beyond the // current kSize space. // For very large search spaces we do a binary chop search of the non-Latin1 // space instead of just going to the end of the current kSize space. The // heuristics are complicated a little by the fact that any 128-character // encoding space can be quickly tested with a table lookup, so we don't // wish to do binary chop search at a smaller granularity than that. A // 128-character space can take up a lot of space in the ranges array if, // for example, we only want to match every second character (eg. the lower // case characters on some Unicode pages). intptr_t binary_chop_index = (end_index + start_index) / 2; // The first test ensures that we get to the code that handles the Latin1 // range with a single not-taken branch, speeding up this important // character range (even non-Latin1 charset-based text has spaces and // punctuation). if (*border - 1 > Symbols::kMaxOneCharCodeSymbol && // Latin1 case. end_index - start_index > (*new_start_index - start_index) * 2 && last - first > kSize * 2 && binary_chop_index > *new_start_index && ranges->At(binary_chop_index) >= first + 2 * kSize) { intptr_t scan_forward_for_section_border = binary_chop_index; intptr_t new_border = (ranges->At(binary_chop_index) | kMask) + 1; while (scan_forward_for_section_border < end_index) { if (ranges->At(scan_forward_for_section_border) > new_border) { *new_start_index = scan_forward_for_section_border; *border = new_border; break; } scan_forward_for_section_border++; } } ASSERT(*new_start_index > start_index); *new_end_index = *new_start_index - 1; if (ranges->At(*new_end_index) == *border) { (*new_end_index)--; } if (*border >= ranges->At(end_index)) { *border = ranges->At(end_index); *new_start_index = end_index; // Won't be used. *new_end_index = end_index - 1; } } // Gets a series of segment boundaries representing a character class. If the // character is in the range between an even and an odd boundary (counting from // start_index) then go to even_label, otherwise go to odd_label. We already // know that the character is in the range of min_char to max_char inclusive. // Either label can be NULL indicating backtracking. Either label can also be // equal to the fall_through label. static void GenerateBranches(RegExpMacroAssembler* masm, ZoneGrowableArray* ranges, intptr_t start_index, intptr_t end_index, uint16_t min_char, uint16_t max_char, BlockLabel* fall_through, BlockLabel* even_label, BlockLabel* odd_label) { uint16_t first = ranges->At(start_index); uint16_t last = ranges->At(end_index) - 1; ASSERT(min_char < first); // Just need to test if the character is before or on-or-after // a particular character. if (start_index == end_index) { EmitBoundaryTest(masm, first, fall_through, even_label, odd_label); return; } // Another almost trivial case: There is one interval in the middle that is // different from the end intervals. if (start_index + 1 == end_index) { EmitDoubleBoundaryTest(masm, first, last, fall_through, even_label, odd_label); return; } // It's not worth using table lookup if there are very few intervals in the // character class. if (end_index - start_index <= 6) { // It is faster to test for individual characters, so we look for those // first, then try arbitrary ranges in the second round. static intptr_t kNoCutIndex = -1; intptr_t cut = kNoCutIndex; for (intptr_t i = start_index; i < end_index; i++) { if (ranges->At(i) == ranges->At(i + 1) - 1) { cut = i; break; } } if (cut == kNoCutIndex) cut = start_index; CutOutRange(masm, ranges, start_index, end_index, cut, even_label, odd_label); ASSERT(end_index - start_index >= 2); GenerateBranches(masm, ranges, start_index + 1, end_index - 1, min_char, max_char, fall_through, even_label, odd_label); return; } // If there are a lot of intervals in the regexp, then we will use tables to // determine whether the character is inside or outside the character class. static const intptr_t kBits = RegExpMacroAssembler::kTableSizeBits; if ((max_char >> kBits) == (min_char >> kBits)) { EmitUseLookupTable(masm, ranges, start_index, end_index, min_char, fall_through, even_label, odd_label); return; } if ((min_char >> kBits) != (first >> kBits)) { masm->CheckCharacterLT(first, odd_label); GenerateBranches(masm, ranges, start_index + 1, end_index, first, max_char, fall_through, odd_label, even_label); return; } intptr_t new_start_index = 0; intptr_t new_end_index = 0; uint16_t border = 0; SplitSearchSpace(ranges, start_index, end_index, &new_start_index, &new_end_index, &border); BlockLabel handle_rest; BlockLabel* above = &handle_rest; if (border == last + 1) { // We didn't find any section that started after the limit, so everything // above the border is one of the terminal labels. above = (end_index & 1) != (start_index & 1) ? odd_label : even_label; ASSERT(new_end_index == end_index - 1); } ASSERT(start_index <= new_end_index); ASSERT(new_start_index <= end_index); ASSERT(start_index < new_start_index); ASSERT(new_end_index < end_index); ASSERT(new_end_index + 1 == new_start_index || (new_end_index + 2 == new_start_index && border == ranges->At(new_end_index + 1))); ASSERT(min_char < border - 1); ASSERT(border < max_char); ASSERT(ranges->At(new_end_index) < border); ASSERT(border < ranges->At(new_start_index) || (border == ranges->At(new_start_index) && new_start_index == end_index && new_end_index == end_index - 1 && border == last + 1)); ASSERT(new_start_index == 0 || border >= ranges->At(new_start_index - 1)); masm->CheckCharacterGT(border - 1, above); BlockLabel dummy; GenerateBranches(masm, ranges, start_index, new_end_index, min_char, border - 1, &dummy, even_label, odd_label); if (handle_rest.IsLinked()) { masm->BindBlock(&handle_rest); bool flip = (new_start_index & 1) != (start_index & 1); GenerateBranches(masm, ranges, new_start_index, end_index, border, max_char, &dummy, flip ? odd_label : even_label, flip ? even_label : odd_label); } } static void EmitCharClass(RegExpMacroAssembler* macro_assembler, RegExpCharacterClass* cc, bool one_byte, BlockLabel* on_failure, intptr_t cp_offset, bool check_offset, bool preloaded, Zone* zone) { ZoneGrowableArray* ranges = cc->ranges(); if (!CharacterRange::IsCanonical(ranges)) { CharacterRange::Canonicalize(ranges); } uint16_t max_char; if (one_byte) { max_char = Symbols::kMaxOneCharCodeSymbol; } else { max_char = Utf16::kMaxCodeUnit; } intptr_t range_count = ranges->length(); intptr_t last_valid_range = range_count - 1; while (last_valid_range >= 0) { const CharacterRange& range = ranges->At(last_valid_range); if (range.from() <= max_char) { break; } last_valid_range--; } if (last_valid_range < 0) { if (!cc->is_negated()) { macro_assembler->GoTo(on_failure); } if (check_offset) { macro_assembler->CheckPosition(cp_offset, on_failure); } return; } if (last_valid_range == 0 && ranges->At(0).IsEverything(max_char)) { if (cc->is_negated()) { macro_assembler->GoTo(on_failure); } else { // This is a common case hit by non-anchored expressions. if (check_offset) { macro_assembler->CheckPosition(cp_offset, on_failure); } } return; } if (!preloaded) { macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check_offset); } if (cc->is_standard() && macro_assembler->CheckSpecialCharacterClass( cc->standard_type(), on_failure)) { return; } // A new list with ascending entries. Each entry is a code unit // where there is a boundary between code units that are part of // the class and code units that are not. Normally we insert an // entry at zero which goes to the failure label, but if there // was already one there we fall through for success on that entry. // Subsequent entries have alternating meaning (success/failure). ZoneGrowableArray* range_boundaries = new (zone) ZoneGrowableArray(last_valid_range); bool zeroth_entry_is_failure = !cc->is_negated(); for (intptr_t i = 0; i <= last_valid_range; i++) { const CharacterRange& range = ranges->At(i); if (range.from() == 0) { ASSERT(i == 0); zeroth_entry_is_failure = !zeroth_entry_is_failure; } else { range_boundaries->Add(range.from()); } if (range.to() + 1 <= max_char) { range_boundaries->Add(range.to() + 1); } } intptr_t end_index = range_boundaries->length() - 1; BlockLabel fall_through; GenerateBranches(macro_assembler, range_boundaries, 0, // start_index. end_index, 0, // min_char. max_char, &fall_through, zeroth_entry_is_failure ? &fall_through : on_failure, zeroth_entry_is_failure ? on_failure : &fall_through); macro_assembler->BindBlock(&fall_through); } RegExpNode::~RegExpNode() {} RegExpNode::LimitResult RegExpNode::LimitVersions(RegExpCompiler* compiler, Trace* trace) { // If we are generating a greedy loop then don't stop and don't reuse code. if (trace->stop_node() != NULL) { return CONTINUE; } RegExpMacroAssembler* macro_assembler = compiler->macro_assembler(); if (trace->is_trivial()) { if (label_.IsBound()) { // We are being asked to generate a generic version, but that's already // been done so just go to it. macro_assembler->GoTo(&label_); return DONE; } if (compiler->recursion_depth() >= RegExpCompiler::kMaxRecursion) { // To avoid too deep recursion we push the node to the work queue and just // generate a goto here. compiler->AddWork(this); macro_assembler->GoTo(&label_); return DONE; } // Generate generic version of the node and bind the label for later use. macro_assembler->BindBlock(&label_); return CONTINUE; } // We are being asked to make a non-generic version. Keep track of how many // non-generic versions we generate so as not to overdo it. trace_count_++; if (kRegexpOptimization && trace_count_ < kMaxCopiesCodeGenerated && compiler->recursion_depth() <= RegExpCompiler::kMaxRecursion) { return CONTINUE; } // If we get here code has been generated for this node too many times or // recursion is too deep. Time to switch to a generic version. The code for // generic versions above can handle deep recursion properly. trace->Flush(compiler, this); return DONE; } intptr_t ActionNode::EatsAtLeast(intptr_t still_to_find, intptr_t budget, bool not_at_start) { if (budget <= 0) return 0; if (action_type_ == POSITIVE_SUBMATCH_SUCCESS) return 0; // Rewinds input! return on_success()->EatsAtLeast(still_to_find, budget - 1, not_at_start); } void ActionNode::FillInBMInfo(intptr_t offset, intptr_t budget, BoyerMooreLookahead* bm, bool not_at_start) { if (action_type_ == BEGIN_SUBMATCH) { bm->SetRest(offset); } else if (action_type_ != POSITIVE_SUBMATCH_SUCCESS) { on_success()->FillInBMInfo(offset, budget - 1, bm, not_at_start); } SaveBMInfo(bm, not_at_start, offset); } intptr_t AssertionNode::EatsAtLeast(intptr_t still_to_find, intptr_t budget, bool not_at_start) { if (budget <= 0) return 0; // If we know we are not at the start and we are asked "how many characters // will you match if you succeed?" then we can answer anything since false // implies false. So lets just return the max answer (still_to_find) since // that won't prevent us from preloading a lot of characters for the other // branches in the node graph. if (assertion_type() == AT_START && not_at_start) return still_to_find; return on_success()->EatsAtLeast(still_to_find, budget - 1, not_at_start); } void AssertionNode::FillInBMInfo(intptr_t offset, intptr_t budget, BoyerMooreLookahead* bm, bool not_at_start) { // Match the behaviour of EatsAtLeast on this node. if (assertion_type() == AT_START && not_at_start) return; on_success()->FillInBMInfo(offset, budget - 1, bm, not_at_start); SaveBMInfo(bm, not_at_start, offset); } intptr_t BackReferenceNode::EatsAtLeast(intptr_t still_to_find, intptr_t budget, bool not_at_start) { if (read_backward()) return 0; if (budget <= 0) return 0; return on_success()->EatsAtLeast(still_to_find, budget - 1, not_at_start); } intptr_t TextNode::EatsAtLeast(intptr_t still_to_find, intptr_t budget, bool not_at_start) { if (read_backward()) return 0; intptr_t answer = Length(); if (answer >= still_to_find) return answer; if (budget <= 0) return answer; // We are not at start after this node so we set the last argument to 'true'. return answer + on_success()->EatsAtLeast(still_to_find - answer, budget - 1, true); } intptr_t NegativeLookaroundChoiceNode::EatsAtLeast(intptr_t still_to_find, intptr_t budget, bool not_at_start) { if (budget <= 0) return 0; // Alternative 0 is the negative lookahead, alternative 1 is what comes // afterwards. RegExpNode* node = (*alternatives_)[1].node(); return node->EatsAtLeast(still_to_find, budget - 1, not_at_start); } void NegativeLookaroundChoiceNode::GetQuickCheckDetails( QuickCheckDetails* details, RegExpCompiler* compiler, intptr_t filled_in, bool not_at_start) { // Alternative 0 is the negative lookahead, alternative 1 is what comes // afterwards. RegExpNode* node = (*alternatives_)[1].node(); return node->GetQuickCheckDetails(details, compiler, filled_in, not_at_start); } intptr_t ChoiceNode::EatsAtLeastHelper(intptr_t still_to_find, intptr_t budget, RegExpNode* ignore_this_node, bool not_at_start) { if (budget <= 0) return 0; intptr_t min = 100; intptr_t choice_count = alternatives_->length(); budget = (budget - 1) / choice_count; for (intptr_t i = 0; i < choice_count; i++) { RegExpNode* node = (*alternatives_)[i].node(); if (node == ignore_this_node) continue; intptr_t node_eats_at_least = node->EatsAtLeast(still_to_find, budget, not_at_start); if (node_eats_at_least < min) min = node_eats_at_least; if (min == 0) return 0; } return min; } intptr_t LoopChoiceNode::EatsAtLeast(intptr_t still_to_find, intptr_t budget, bool not_at_start) { return EatsAtLeastHelper(still_to_find, budget - 1, loop_node_, not_at_start); } intptr_t ChoiceNode::EatsAtLeast(intptr_t still_to_find, intptr_t budget, bool not_at_start) { return EatsAtLeastHelper(still_to_find, budget, NULL, not_at_start); } // Takes the left-most 1-bit and smears it out, setting all bits to its right. static inline uint32_t SmearBitsRight(uint32_t v) { v |= v >> 1; v |= v >> 2; v |= v >> 4; v |= v >> 8; v |= v >> 16; return v; } bool QuickCheckDetails::Rationalize(bool asc) { bool found_useful_op = false; uint32_t char_mask; if (asc) { char_mask = Symbols::kMaxOneCharCodeSymbol; } else { char_mask = Utf16::kMaxCodeUnit; } mask_ = 0; value_ = 0; intptr_t char_shift = 0; for (intptr_t i = 0; i < characters_; i++) { Position* pos = &positions_[i]; if ((pos->mask & Symbols::kMaxOneCharCodeSymbol) != 0) { found_useful_op = true; } mask_ |= (pos->mask & char_mask) << char_shift; value_ |= (pos->value & char_mask) << char_shift; char_shift += asc ? 8 : 16; } return found_useful_op; } bool RegExpNode::EmitQuickCheck(RegExpCompiler* compiler, Trace* bounds_check_trace, Trace* trace, bool preload_has_checked_bounds, BlockLabel* on_possible_success, QuickCheckDetails* details, bool fall_through_on_failure) { if (details->characters() == 0) return false; GetQuickCheckDetails(details, compiler, 0, trace->at_start() == Trace::FALSE_VALUE); if (details->cannot_match()) return false; if (!details->Rationalize(compiler->one_byte())) return false; ASSERT(details->characters() == 1 || compiler->macro_assembler()->CanReadUnaligned()); uint32_t mask = details->mask(); uint32_t value = details->value(); RegExpMacroAssembler* assembler = compiler->macro_assembler(); if (trace->characters_preloaded() != details->characters()) { ASSERT(trace->cp_offset() == bounds_check_trace->cp_offset()); // We are attempting to preload the minimum number of characters // any choice would eat, so if the bounds check fails, then none of the // choices can succeed, so we can just immediately backtrack, rather // than go to the next choice. assembler->LoadCurrentCharacter( trace->cp_offset(), bounds_check_trace->backtrack(), !preload_has_checked_bounds, details->characters()); } bool need_mask = true; if (details->characters() == 1) { // If number of characters preloaded is 1 then we used a byte or 16 bit // load so the value is already masked down. uint32_t char_mask; if (compiler->one_byte()) { char_mask = Symbols::kMaxOneCharCodeSymbol; } else { char_mask = Utf16::kMaxCodeUnit; } if ((mask & char_mask) == char_mask) need_mask = false; mask &= char_mask; } else { // For 2-character preloads in one-byte mode or 1-character preloads in // two-byte mode we also use a 16 bit load with zero extend. if (details->characters() == 2 && compiler->one_byte()) { if ((mask & 0xffff) == 0xffff) need_mask = false; } else if (details->characters() == 1 && !compiler->one_byte()) { if ((mask & 0xffff) == 0xffff) need_mask = false; } else { if (mask == 0xffffffff) need_mask = false; } } if (fall_through_on_failure) { if (need_mask) { assembler->CheckCharacterAfterAnd(value, mask, on_possible_success); } else { assembler->CheckCharacter(value, on_possible_success); } } else { if (need_mask) { assembler->CheckNotCharacterAfterAnd(value, mask, trace->backtrack()); } else { assembler->CheckNotCharacter(value, trace->backtrack()); } } return true; } // Here is the meat of GetQuickCheckDetails (see also the comment on the // super-class in the .h file). // // We iterate along the text object, building up for each character a // mask and value that can be used to test for a quick failure to match. // The masks and values for the positions will be combined into a single // machine word for the current character width in order to be used in // generating a quick check. void TextNode::GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, intptr_t characters_filled_in, bool not_at_start) { #if defined(__GNUC__) && defined(__BYTE_ORDER__) // TODO(zerny): Make the combination code byte-order independent. ASSERT(details->characters() == 1 || (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)); #endif // Do not collect any quick check details if the text node reads backward, // since it reads in the opposite direction than we use for quick checks. if (read_backward()) return; ASSERT(characters_filled_in < details->characters()); intptr_t characters = details->characters(); int32_t char_mask; if (compiler->one_byte()) { char_mask = Symbols::kMaxOneCharCodeSymbol; } else { char_mask = Utf16::kMaxCodeUnit; } for (intptr_t k = 0; k < elms_->length(); k++) { TextElement elm = elms_->At(k); if (elm.text_type() == TextElement::ATOM) { ZoneGrowableArray* quarks = elm.atom()->data(); for (intptr_t i = 0; i < characters && i < quarks->length(); i++) { QuickCheckDetails::Position* pos = details->positions(characters_filled_in); uint16_t c = quarks->At(i); if (c > char_mask) { // If we expect a non-Latin1 character from an one-byte string, // there is no way we can match. Not even case independent // matching can turn an Latin1 character into non-Latin1 or // vice versa. // TODO(dcarney): issue 3550. Verify that this works as expected. // For example, \u0178 is uppercase of \u00ff (y-umlaut). details->set_cannot_match(); pos->determines_perfectly = false; return; } if (elm.atom()->ignore_case()) { int32_t chars[unibrow::Ecma262UnCanonicalize::kMaxWidth]; intptr_t length = GetCaseIndependentLetters(c, compiler->one_byte(), chars); ASSERT(length != 0); // Can only happen if c > char_mask (see above). if (length == 1) { // This letter has no case equivalents, so it's nice and simple // and the mask-compare will determine definitely whether we have // a match at this character position. pos->mask = char_mask; pos->value = c; pos->determines_perfectly = true; } else { uint32_t common_bits = char_mask; uint32_t bits = chars[0]; for (intptr_t j = 1; j < length; j++) { uint32_t differing_bits = ((chars[j] & common_bits) ^ bits); common_bits ^= differing_bits; bits &= common_bits; } // If length is 2 and common bits has only one zero in it then // our mask and compare instruction will determine definitely // whether we have a match at this character position. Otherwise // it can only be an approximate check. uint32_t one_zero = (common_bits | ~char_mask); if (length == 2 && ((~one_zero) & ((~one_zero) - 1)) == 0) { pos->determines_perfectly = true; } pos->mask = common_bits; pos->value = bits; } } else { // Don't ignore case. Nice simple case where the mask-compare will // determine definitely whether we have a match at this character // position. pos->mask = char_mask; pos->value = c; pos->determines_perfectly = true; } characters_filled_in++; ASSERT(characters_filled_in <= details->characters()); if (characters_filled_in == details->characters()) { return; } } } else { QuickCheckDetails::Position* pos = details->positions(characters_filled_in); RegExpCharacterClass* tree = elm.char_class(); ZoneGrowableArray* ranges = tree->ranges(); ASSERT(!ranges->is_empty()); if (tree->is_negated()) { // A quick check uses multi-character mask and compare. There is no // useful way to incorporate a negative char class into this scheme // so we just conservatively create a mask and value that will always // succeed. pos->mask = 0; pos->value = 0; } else { intptr_t first_range = 0; while (ranges->At(first_range).from() > char_mask) { first_range++; if (first_range == ranges->length()) { details->set_cannot_match(); pos->determines_perfectly = false; return; } } CharacterRange range = ranges->At(first_range); uint16_t from = range.from(); uint16_t to = range.to(); if (to > char_mask) { to = char_mask; } uint32_t differing_bits = (from ^ to); // A mask and compare is only perfect if the differing bits form a // number like 00011111 with one single block of trailing 1s. if ((differing_bits & (differing_bits + 1)) == 0 && from + differing_bits == to) { pos->determines_perfectly = true; } uint32_t common_bits = ~SmearBitsRight(differing_bits); uint32_t bits = (from & common_bits); for (intptr_t i = first_range + 1; i < ranges->length(); i++) { CharacterRange range = ranges->At(i); uint16_t from = range.from(); uint16_t to = range.to(); if (from > char_mask) continue; if (to > char_mask) to = char_mask; // Here we are combining more ranges into the mask and compare // value. With each new range the mask becomes more sparse and // so the chances of a false positive rise. A character class // with multiple ranges is assumed never to be equivalent to a // mask and compare operation. pos->determines_perfectly = false; uint32_t new_common_bits = (from ^ to); new_common_bits = ~SmearBitsRight(new_common_bits); common_bits &= new_common_bits; bits &= new_common_bits; uint32_t differing_bits = (from & common_bits) ^ bits; common_bits ^= differing_bits; bits &= common_bits; } pos->mask = common_bits; pos->value = bits; } characters_filled_in++; ASSERT(characters_filled_in <= details->characters()); if (characters_filled_in == details->characters()) { return; } } } ASSERT(characters_filled_in != details->characters()); if (!details->cannot_match()) { on_success()->GetQuickCheckDetails(details, compiler, characters_filled_in, true); } } void QuickCheckDetails::Clear() { for (int i = 0; i < characters_; i++) { positions_[i].mask = 0; positions_[i].value = 0; positions_[i].determines_perfectly = false; } characters_ = 0; } void QuickCheckDetails::Advance(intptr_t by, bool one_byte) { if (by >= characters_ || by < 0) { // check that by < 0 => characters_ == 0 ASSERT(by >= 0 || characters_ == 0); Clear(); return; } for (intptr_t i = 0; i < characters_ - by; i++) { positions_[i] = positions_[by + i]; } for (intptr_t i = characters_ - by; i < characters_; i++) { positions_[i].mask = 0; positions_[i].value = 0; positions_[i].determines_perfectly = false; } characters_ -= by; // We could change mask_ and value_ here but we would never advance unless // they had already been used in a check and they won't be used again because // it would gain us nothing. So there's no point. } void QuickCheckDetails::Merge(QuickCheckDetails* other, intptr_t from_index) { ASSERT(characters_ == other->characters_); if (other->cannot_match_) { return; } if (cannot_match_) { *this = *other; return; } for (intptr_t i = from_index; i < characters_; i++) { QuickCheckDetails::Position* pos = positions(i); QuickCheckDetails::Position* other_pos = other->positions(i); if (pos->mask != other_pos->mask || pos->value != other_pos->value || !other_pos->determines_perfectly) { // Our mask-compare operation will be approximate unless we have the // exact same operation on both sides of the alternation. pos->determines_perfectly = false; } pos->mask &= other_pos->mask; pos->value &= pos->mask; other_pos->value &= pos->mask; uint16_t differing_bits = (pos->value ^ other_pos->value); pos->mask &= ~differing_bits; pos->value &= pos->mask; } } class VisitMarker : public ValueObject { public: explicit VisitMarker(NodeInfo* info) : info_(info) { ASSERT(!info->visited); info->visited = true; } ~VisitMarker() { info_->visited = false; } private: NodeInfo* info_; }; RegExpNode* SeqRegExpNode::FilterOneByte(intptr_t depth) { if (info()->replacement_calculated) return replacement(); if (depth < 0) return this; ASSERT(!info()->visited); VisitMarker marker(info()); return FilterSuccessor(depth - 1); } RegExpNode* SeqRegExpNode::FilterSuccessor(intptr_t depth) { RegExpNode* next = on_success_->FilterOneByte(depth - 1); if (next == NULL) return set_replacement(NULL); on_success_ = next; return set_replacement(this); } // We need to check for the following characters: 0x39c 0x3bc 0x178. static inline bool RangeContainsLatin1Equivalents(CharacterRange range) { // TODO(dcarney): this could be a lot more efficient. return range.Contains(0x39c) || range.Contains(0x3bc) || range.Contains(0x178); } static bool RangesContainLatin1Equivalents( ZoneGrowableArray* ranges) { for (intptr_t i = 0; i < ranges->length(); i++) { // TODO(dcarney): this could be a lot more efficient. if (RangeContainsLatin1Equivalents(ranges->At(i))) return true; } return false; } static uint16_t ConvertNonLatin1ToLatin1(uint16_t c) { ASSERT(c > Symbols::kMaxOneCharCodeSymbol); switch (c) { // This are equivalent characters in unicode. case 0x39c: case 0x3bc: return 0xb5; // This is an uppercase of a Latin-1 character // outside of Latin-1. case 0x178: return 0xff; } return 0; } RegExpNode* TextNode::FilterOneByte(intptr_t depth) { if (info()->replacement_calculated) return replacement(); if (depth < 0) return this; ASSERT(!info()->visited); VisitMarker marker(info()); intptr_t element_count = elms_->length(); for (intptr_t i = 0; i < element_count; i++) { TextElement elm = elms_->At(i); if (elm.text_type() == TextElement::ATOM) { ZoneGrowableArray* quarks = elm.atom()->data(); for (intptr_t j = 0; j < quarks->length(); j++) { uint16_t c = quarks->At(j); if (c <= Symbols::kMaxOneCharCodeSymbol) continue; if (!elm.atom()->ignore_case()) return set_replacement(NULL); // Here, we need to check for characters whose upper and lower cases // are outside the Latin-1 range. uint16_t converted = ConvertNonLatin1ToLatin1(c); // Character is outside Latin-1 completely if (converted == 0) return set_replacement(NULL); // Convert quark to Latin-1 in place. (*quarks)[0] = converted; } } else { ASSERT(elm.text_type() == TextElement::CHAR_CLASS); RegExpCharacterClass* cc = elm.char_class(); ZoneGrowableArray* ranges = cc->ranges(); if (!CharacterRange::IsCanonical(ranges)) { CharacterRange::Canonicalize(ranges); } // Now they are in order so we only need to look at the first. intptr_t range_count = ranges->length(); if (cc->is_negated()) { if (range_count != 0 && ranges->At(0).from() == 0 && ranges->At(0).to() >= Symbols::kMaxOneCharCodeSymbol) { // This will be handled in a later filter. if (cc->flags().IgnoreCase() && RangesContainLatin1Equivalents(ranges)) { continue; } return set_replacement(NULL); } } else { if (range_count == 0 || ranges->At(0).from() > Symbols::kMaxOneCharCodeSymbol) { // This will be handled in a later filter. if (cc->flags().IgnoreCase() && RangesContainLatin1Equivalents(ranges)) continue; return set_replacement(NULL); } } } } return FilterSuccessor(depth - 1); } RegExpNode* LoopChoiceNode::FilterOneByte(intptr_t depth) { if (info()->replacement_calculated) return replacement(); if (depth < 0) return this; if (info()->visited) return this; { VisitMarker marker(info()); RegExpNode* continue_replacement = continue_node_->FilterOneByte(depth - 1); // If we can't continue after the loop then there is no sense in doing the // loop. if (continue_replacement == NULL) return set_replacement(NULL); } return ChoiceNode::FilterOneByte(depth - 1); } RegExpNode* ChoiceNode::FilterOneByte(intptr_t depth) { if (info()->replacement_calculated) return replacement(); if (depth < 0) return this; if (info()->visited) return this; VisitMarker marker(info()); intptr_t choice_count = alternatives_->length(); for (intptr_t i = 0; i < choice_count; i++) { GuardedAlternative alternative = alternatives_->At(i); if (alternative.guards() != NULL && alternative.guards()->length() != 0) { set_replacement(this); return this; } } intptr_t surviving = 0; RegExpNode* survivor = NULL; for (intptr_t i = 0; i < choice_count; i++) { GuardedAlternative alternative = alternatives_->At(i); RegExpNode* replacement = alternative.node()->FilterOneByte(depth - 1); ASSERT(replacement != this); // No missing EMPTY_MATCH_CHECK. if (replacement != NULL) { (*alternatives_)[i].set_node(replacement); surviving++; survivor = replacement; } } if (surviving < 2) return set_replacement(survivor); set_replacement(this); if (surviving == choice_count) { return this; } // Only some of the nodes survived the filtering. We need to rebuild the // alternatives list. ZoneGrowableArray* new_alternatives = new (Z) ZoneGrowableArray(surviving); for (intptr_t i = 0; i < choice_count; i++) { RegExpNode* replacement = (*alternatives_)[i].node()->FilterOneByte(depth - 1); if (replacement != NULL) { (*alternatives_)[i].set_node(replacement); new_alternatives->Add((*alternatives_)[i]); } } alternatives_ = new_alternatives; return this; } RegExpNode* NegativeLookaroundChoiceNode::FilterOneByte(intptr_t depth) { if (info()->replacement_calculated) return replacement(); if (depth < 0) return this; if (info()->visited) return this; VisitMarker marker(info()); // Alternative 0 is the negative lookahead, alternative 1 is what comes // afterwards. RegExpNode* node = (*alternatives_)[1].node(); RegExpNode* replacement = node->FilterOneByte(depth - 1); if (replacement == NULL) return set_replacement(NULL); (*alternatives_)[1].set_node(replacement); RegExpNode* neg_node = (*alternatives_)[0].node(); RegExpNode* neg_replacement = neg_node->FilterOneByte(depth - 1); // If the negative lookahead is always going to fail then // we don't need to check it. if (neg_replacement == NULL) return set_replacement(replacement); (*alternatives_)[0].set_node(neg_replacement); return set_replacement(this); } void LoopChoiceNode::GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, intptr_t characters_filled_in, bool not_at_start) { if (body_can_be_zero_length_ || info()->visited) return; VisitMarker marker(info()); return ChoiceNode::GetQuickCheckDetails(details, compiler, characters_filled_in, not_at_start); } void LoopChoiceNode::FillInBMInfo(intptr_t offset, intptr_t budget, BoyerMooreLookahead* bm, bool not_at_start) { if (body_can_be_zero_length_ || budget <= 0) { bm->SetRest(offset); SaveBMInfo(bm, not_at_start, offset); return; } ChoiceNode::FillInBMInfo(offset, budget - 1, bm, not_at_start); SaveBMInfo(bm, not_at_start, offset); } void ChoiceNode::GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, intptr_t characters_filled_in, bool not_at_start) { not_at_start = (not_at_start || not_at_start_); intptr_t choice_count = alternatives_->length(); ASSERT(choice_count > 0); (*alternatives_)[0].node()->GetQuickCheckDetails( details, compiler, characters_filled_in, not_at_start); for (intptr_t i = 1; i < choice_count; i++) { QuickCheckDetails new_details(details->characters()); RegExpNode* node = (*alternatives_)[i].node(); node->GetQuickCheckDetails(&new_details, compiler, characters_filled_in, not_at_start); // Here we merge the quick match details of the two branches. details->Merge(&new_details, characters_filled_in); } } // Check for [0-9A-Z_a-z]. static void EmitWordCheck(RegExpMacroAssembler* assembler, BlockLabel* word, BlockLabel* non_word, bool fall_through_on_word) { if (assembler->CheckSpecialCharacterClass( fall_through_on_word ? 'w' : 'W', fall_through_on_word ? non_word : word)) { // Optimized implementation available. return; } assembler->CheckCharacterGT('z', non_word); assembler->CheckCharacterLT('0', non_word); assembler->CheckCharacterGT('a' - 1, word); assembler->CheckCharacterLT('9' + 1, word); assembler->CheckCharacterLT('A', non_word); assembler->CheckCharacterLT('Z' + 1, word); if (fall_through_on_word) { assembler->CheckNotCharacter('_', non_word); } else { assembler->CheckCharacter('_', word); } } // Emit the code to check for a ^ in multiline mode (1-character lookbehind // that matches newline or the start of input). static void EmitHat(RegExpCompiler* compiler, RegExpNode* on_success, Trace* trace) { RegExpMacroAssembler* assembler = compiler->macro_assembler(); // We will be loading the previous character into the current character // register. Trace new_trace(*trace); new_trace.InvalidateCurrentCharacter(); BlockLabel ok; if (new_trace.cp_offset() == 0) { // The start of input counts as a newline in this context, so skip to // ok if we are at the start. assembler->CheckAtStart(&ok); } // We already checked that we are not at the start of input so it must be // OK to load the previous character. assembler->LoadCurrentCharacter(new_trace.cp_offset() - 1, new_trace.backtrack(), false); if (!assembler->CheckSpecialCharacterClass('n', new_trace.backtrack())) { // Newline means \n, \r, 0x2028 or 0x2029. if (!compiler->one_byte()) { assembler->CheckCharacterAfterAnd(0x2028, 0xfffe, &ok); } assembler->CheckCharacter('\n', &ok); assembler->CheckNotCharacter('\r', new_trace.backtrack()); } assembler->BindBlock(&ok); on_success->Emit(compiler, &new_trace); } // Emit the code to handle \b and \B (word-boundary or non-word-boundary). void AssertionNode::EmitBoundaryCheck(RegExpCompiler* compiler, Trace* trace) { RegExpMacroAssembler* assembler = compiler->macro_assembler(); Trace::TriBool next_is_word_character = Trace::UNKNOWN; bool not_at_start = (trace->at_start() == Trace::FALSE_VALUE); BoyerMooreLookahead* lookahead = bm_info(not_at_start); if (lookahead == NULL) { intptr_t eats_at_least = Utils::Minimum(kMaxLookaheadForBoyerMoore, EatsAtLeast(kMaxLookaheadForBoyerMoore, kRecursionBudget, not_at_start)); if (eats_at_least >= 1) { BoyerMooreLookahead* bm = new (Z) BoyerMooreLookahead(eats_at_least, compiler, Z); FillInBMInfo(0, kRecursionBudget, bm, not_at_start); if (bm->at(0)->is_non_word()) next_is_word_character = Trace::FALSE_VALUE; if (bm->at(0)->is_word()) next_is_word_character = Trace::TRUE_VALUE; } } else { if (lookahead->at(0)->is_non_word()) next_is_word_character = Trace::FALSE_VALUE; if (lookahead->at(0)->is_word()) next_is_word_character = Trace::TRUE_VALUE; } bool at_boundary = (assertion_type_ == AssertionNode::AT_BOUNDARY); if (next_is_word_character == Trace::UNKNOWN) { BlockLabel before_non_word; BlockLabel before_word; if (trace->characters_preloaded() != 1) { assembler->LoadCurrentCharacter(trace->cp_offset(), &before_non_word); } // Fall through on non-word. EmitWordCheck(assembler, &before_word, &before_non_word, false); // Next character is not a word character. assembler->BindBlock(&before_non_word); BlockLabel ok; // Backtrack on \B (non-boundary check) if previous is a word, // since we know next *is not* a word and this would be a boundary. BacktrackIfPrevious(compiler, trace, at_boundary ? kIsNonWord : kIsWord); if (!assembler->IsClosed()) { assembler->GoTo(&ok); } assembler->BindBlock(&before_word); BacktrackIfPrevious(compiler, trace, at_boundary ? kIsWord : kIsNonWord); assembler->BindBlock(&ok); } else if (next_is_word_character == Trace::TRUE_VALUE) { BacktrackIfPrevious(compiler, trace, at_boundary ? kIsWord : kIsNonWord); } else { ASSERT(next_is_word_character == Trace::FALSE_VALUE); BacktrackIfPrevious(compiler, trace, at_boundary ? kIsNonWord : kIsWord); } } void AssertionNode::BacktrackIfPrevious( RegExpCompiler* compiler, Trace* trace, AssertionNode::IfPrevious backtrack_if_previous) { RegExpMacroAssembler* assembler = compiler->macro_assembler(); Trace new_trace(*trace); new_trace.InvalidateCurrentCharacter(); BlockLabel fall_through, dummy; BlockLabel* non_word = backtrack_if_previous == kIsNonWord ? new_trace.backtrack() : &fall_through; BlockLabel* word = backtrack_if_previous == kIsNonWord ? &fall_through : new_trace.backtrack(); if (new_trace.cp_offset() == 0) { // The start of input counts as a non-word character, so the question is // decided if we are at the start. assembler->CheckAtStart(non_word); } // We already checked that we are not at the start of input so it must be // OK to load the previous character. assembler->LoadCurrentCharacter(new_trace.cp_offset() - 1, &dummy, false); EmitWordCheck(assembler, word, non_word, backtrack_if_previous == kIsNonWord); assembler->BindBlock(&fall_through); on_success()->Emit(compiler, &new_trace); } void AssertionNode::GetQuickCheckDetails(QuickCheckDetails* details, RegExpCompiler* compiler, intptr_t filled_in, bool not_at_start) { if (assertion_type_ == AT_START && not_at_start) { details->set_cannot_match(); return; } return on_success()->GetQuickCheckDetails(details, compiler, filled_in, not_at_start); } void AssertionNode::Emit(RegExpCompiler* compiler, Trace* trace) { RegExpMacroAssembler* assembler = compiler->macro_assembler(); switch (assertion_type_) { case AT_END: { BlockLabel ok; assembler->CheckPosition(trace->cp_offset(), &ok); assembler->GoTo(trace->backtrack()); assembler->BindBlock(&ok); break; } case AT_START: { if (trace->at_start() == Trace::FALSE_VALUE) { assembler->GoTo(trace->backtrack()); return; } if (trace->at_start() == Trace::UNKNOWN) { assembler->CheckNotAtStart(trace->cp_offset(), trace->backtrack()); Trace at_start_trace = *trace; at_start_trace.set_at_start(Trace::TRUE_VALUE); on_success()->Emit(compiler, &at_start_trace); return; } } break; case AFTER_NEWLINE: EmitHat(compiler, on_success(), trace); return; case AT_BOUNDARY: case AT_NON_BOUNDARY: { EmitBoundaryCheck(compiler, trace); return; } } on_success()->Emit(compiler, trace); } static bool DeterminedAlready(QuickCheckDetails* quick_check, intptr_t offset) { if (quick_check == NULL) return false; if (offset >= quick_check->characters()) return false; return quick_check->positions(offset)->determines_perfectly; } static void UpdateBoundsCheck(intptr_t index, intptr_t* checked_up_to) { if (index > *checked_up_to) { *checked_up_to = index; } } // We call this repeatedly to generate code for each pass over the text node. // The passes are in increasing order of difficulty because we hope one // of the first passes will fail in which case we are saved the work of the // later passes. for example for the case independent regexp /%[asdfghjkl]a/ // we will check the '%' in the first pass, the case independent 'a' in the // second pass and the character class in the last pass. // // The passes are done from right to left, so for example to test for /bar/ // we will first test for an 'r' with offset 2, then an 'a' with offset 1 // and then a 'b' with offset 0. This means we can avoid the end-of-input // bounds check most of the time. In the example we only need to check for // end-of-input when loading the putative 'r'. // // A slight complication involves the fact that the first character may already // be fetched into a register by the previous node. In this case we want to // do the test for that character first. We do this in separate passes. The // 'preloaded' argument indicates that we are doing such a 'pass'. If such a // pass has been performed then subsequent passes will have true in // first_element_checked to indicate that that character does not need to be // checked again. // // In addition to all this we are passed a Trace, which can // contain an AlternativeGeneration object. In this AlternativeGeneration // object we can see details of any quick check that was already passed in // order to get to the code we are now generating. The quick check can involve // loading characters, which means we do not need to recheck the bounds // up to the limit the quick check already checked. In addition the quick // check can have involved a mask and compare operation which may simplify // or obviate the need for further checks at some character positions. void TextNode::TextEmitPass(RegExpCompiler* compiler, TextEmitPassType pass, bool preloaded, Trace* trace, bool first_element_checked, intptr_t* checked_up_to) { RegExpMacroAssembler* assembler = compiler->macro_assembler(); bool one_byte = compiler->one_byte(); BlockLabel* backtrack = trace->backtrack(); QuickCheckDetails* quick_check = trace->quick_check_performed(); intptr_t element_count = elms_->length(); intptr_t backward_offset = read_backward() ? -Length() : 0; for (intptr_t i = preloaded ? 0 : element_count - 1; i >= 0; i--) { TextElement elm = elms_->At(i); intptr_t cp_offset = trace->cp_offset() + elm.cp_offset() + backward_offset; if (elm.text_type() == TextElement::ATOM) { ZoneGrowableArray* quarks = elm.atom()->data(); for (intptr_t j = preloaded ? 0 : quarks->length() - 1; j >= 0; j--) { if (SkipPass(pass, elm.atom()->ignore_case())) continue; if (first_element_checked && i == 0 && j == 0) continue; if (DeterminedAlready(quick_check, elm.cp_offset() + j)) continue; EmitCharacterFunction* emit_function = NULL; uint16_t quark = quarks->At(j); if (elm.atom()->ignore_case()) { // Everywhere else we assume that a non-Latin-1 character cannot match // a Latin-1 character. Avoid the cases where this is assumption is // invalid by using the Latin1 equivalent instead. quark = Latin1::TryConvertToLatin1(quark); } switch (pass) { case NON_LATIN1_MATCH: ASSERT(one_byte); if (quark > Symbols::kMaxOneCharCodeSymbol) { assembler->GoTo(backtrack); return; } break; case NON_LETTER_CHARACTER_MATCH: emit_function = &EmitAtomNonLetter; break; case SIMPLE_CHARACTER_MATCH: emit_function = &EmitSimpleCharacter; break; case CASE_CHARACTER_MATCH: emit_function = &EmitAtomLetter; break; default: break; } if (emit_function != NULL) { const bool bounds_check = *checked_up_to < (cp_offset + j) || read_backward(); bool bound_checked = emit_function(Z, compiler, quarks->At(j), backtrack, cp_offset + j, bounds_check, preloaded); if (bound_checked) UpdateBoundsCheck(cp_offset + j, checked_up_to); } } } else { ASSERT(elm.text_type() == TextElement::CHAR_CLASS); if (pass == CHARACTER_CLASS_MATCH) { if (first_element_checked && i == 0) continue; if (DeterminedAlready(quick_check, elm.cp_offset())) continue; RegExpCharacterClass* cc = elm.char_class(); bool bounds_check = *checked_up_to < cp_offset || read_backward(); EmitCharClass(assembler, cc, one_byte, backtrack, cp_offset, bounds_check, preloaded, Z); UpdateBoundsCheck(cp_offset, checked_up_to); } } } } intptr_t TextNode::Length() { TextElement elm = elms_->Last(); ASSERT(elm.cp_offset() >= 0); return elm.cp_offset() + elm.length(); } bool TextNode::SkipPass(intptr_t intptr_t_pass, bool ignore_case) { TextEmitPassType pass = static_cast(intptr_t_pass); if (ignore_case) { return pass == SIMPLE_CHARACTER_MATCH; } else { return pass == NON_LETTER_CHARACTER_MATCH || pass == CASE_CHARACTER_MATCH; } } TextNode* TextNode::CreateForCharacterRanges( ZoneGrowableArray* ranges, bool read_backward, RegExpNode* on_success, RegExpFlags flags) { ASSERT(ranges != nullptr); ZoneGrowableArray* elms = new ZoneGrowableArray(1); elms->Add(TextElement::CharClass(new RegExpCharacterClass(ranges, flags))); return new TextNode(elms, read_backward, on_success); } TextNode* TextNode::CreateForSurrogatePair(CharacterRange lead, CharacterRange trail, bool read_backward, RegExpNode* on_success, RegExpFlags flags) { auto lead_ranges = CharacterRange::List(on_success->zone(), lead); auto trail_ranges = CharacterRange::List(on_success->zone(), trail); auto elms = new ZoneGrowableArray(2); elms->Add( TextElement::CharClass(new RegExpCharacterClass(lead_ranges, flags))); elms->Add( TextElement::CharClass(new RegExpCharacterClass(trail_ranges, flags))); return new TextNode(elms, read_backward, on_success); } // This generates the code to match a text node. A text node can contain // straight character sequences (possibly to be matched in a case-independent // way) and character classes. For efficiency we do not do this in a single // pass from left to right. Instead we pass over the text node several times, // emitting code for some character positions every time. See the comment on // TextEmitPass for details. void TextNode::Emit(RegExpCompiler* compiler, Trace* trace) { LimitResult limit_result = LimitVersions(compiler, trace); if (limit_result == DONE) return; ASSERT(limit_result == CONTINUE); if (trace->cp_offset() + Length() > RegExpMacroAssembler::kMaxCPOffset) { compiler->SetRegExpTooBig(); return; } if (compiler->one_byte()) { intptr_t dummy = 0; TextEmitPass(compiler, NON_LATIN1_MATCH, false, trace, false, &dummy); } bool first_elt_done = false; intptr_t bound_checked_to = trace->cp_offset() - 1; bound_checked_to += trace->bound_checked_up_to(); // If a character is preloaded into the current character register then // check that now. if (trace->characters_preloaded() == 1) { for (intptr_t pass = kFirstRealPass; pass <= kLastPass; pass++) { TextEmitPass(compiler, static_cast(pass), true, trace, false, &bound_checked_to); } first_elt_done = true; } for (intptr_t pass = kFirstRealPass; pass <= kLastPass; pass++) { TextEmitPass(compiler, static_cast(pass), false, trace, first_elt_done, &bound_checked_to); } Trace successor_trace(*trace); // If we advance backward, we may end up at the start. successor_trace.AdvanceCurrentPositionInTrace( read_backward() ? -Length() : Length(), compiler); successor_trace.set_at_start(read_backward() ? Trace::UNKNOWN : Trace::FALSE_VALUE); RecursionCheck rc(compiler); on_success()->Emit(compiler, &successor_trace); } void Trace::InvalidateCurrentCharacter() { characters_preloaded_ = 0; } void Trace::AdvanceCurrentPositionInTrace(intptr_t by, RegExpCompiler* compiler) { // We don't have an instruction for shifting the current character register // down or for using a shifted value for anything so lets just forget that // we preloaded any characters into it. characters_preloaded_ = 0; // Adjust the offsets of the quick check performed information. This // information is used to find out what we already determined about the // characters by means of mask and compare. quick_check_performed_.Advance(by, compiler->one_byte()); cp_offset_ += by; if (cp_offset_ > RegExpMacroAssembler::kMaxCPOffset) { compiler->SetRegExpTooBig(); cp_offset_ = 0; } bound_checked_up_to_ = Utils::Maximum(static_cast(0), bound_checked_up_to_ - by); } void TextNode::MakeCaseIndependent(bool is_one_byte) { intptr_t element_count = elms_->length(); for (intptr_t i = 0; i < element_count; i++) { TextElement elm = elms_->At(i); if (elm.text_type() == TextElement::CHAR_CLASS) { RegExpCharacterClass* cc = elm.char_class(); bool case_equivalents_already_added = cc->flags().NeedsUnicodeCaseEquivalents(); if (cc->flags().IgnoreCase() && !case_equivalents_already_added) { // None of the standard character classes is different in the case // independent case and it slows us down if we don't know that. if (cc->is_standard()) continue; CharacterRange::AddCaseEquivalents(cc->ranges(), is_one_byte, Z); } } } } intptr_t TextNode::GreedyLoopTextLength() { TextElement elm = elms_->At(elms_->length() - 1); return elm.cp_offset() + elm.length(); } RegExpNode* TextNode::GetSuccessorOfOmnivorousTextNode( RegExpCompiler* compiler) { if (read_backward()) return nullptr; if (elms_->length() != 1) return NULL; TextElement elm = elms_->At(0); if (elm.text_type() != TextElement::CHAR_CLASS) return NULL; RegExpCharacterClass* node = elm.char_class(); ZoneGrowableArray* ranges = node->ranges(); if (!CharacterRange::IsCanonical(ranges)) { CharacterRange::Canonicalize(ranges); } if (node->is_negated()) { return ranges->length() == 0 ? on_success() : NULL; } if (ranges->length() != 1) return NULL; uint32_t max_char; if (compiler->one_byte()) { max_char = Symbols::kMaxOneCharCodeSymbol; } else { max_char = Utf16::kMaxCodeUnit; } return ranges->At(0).IsEverything(max_char) ? on_success() : NULL; } // Finds the fixed match length of a sequence of nodes that goes from // this alternative and back to this choice node. If there are variable // length nodes or other complications in the way then return a sentinel // value indicating that a greedy loop cannot be constructed. intptr_t ChoiceNode::GreedyLoopTextLengthForAlternative( const GuardedAlternative* alternative) { intptr_t length = 0; RegExpNode* node = alternative->node(); // Later we will generate code for all these text nodes using recursion // so we have to limit the max number. intptr_t recursion_depth = 0; while (node != this) { if (recursion_depth++ > RegExpCompiler::kMaxRecursion) { return kNodeIsTooComplexForGreedyLoops; } intptr_t node_length = node->GreedyLoopTextLength(); if (node_length == kNodeIsTooComplexForGreedyLoops) { return kNodeIsTooComplexForGreedyLoops; } length += node_length; SeqRegExpNode* seq_node = static_cast(node); node = seq_node->on_success(); } return read_backward() ? -length : length; } void LoopChoiceNode::AddLoopAlternative(GuardedAlternative alt) { ASSERT(loop_node_ == NULL); AddAlternative(alt); loop_node_ = alt.node(); } void LoopChoiceNode::AddContinueAlternative(GuardedAlternative alt) { ASSERT(continue_node_ == NULL); AddAlternative(alt); continue_node_ = alt.node(); } void LoopChoiceNode::Emit(RegExpCompiler* compiler, Trace* trace) { RegExpMacroAssembler* macro_assembler = compiler->macro_assembler(); if (trace->stop_node() == this) { // Back edge of greedy optimized loop node graph. intptr_t text_length = GreedyLoopTextLengthForAlternative(&alternatives_->At(0)); ASSERT(text_length != kNodeIsTooComplexForGreedyLoops); // Update the counter-based backtracking info on the stack. This is an // optimization for greedy loops (see below). ASSERT(trace->cp_offset() == text_length); macro_assembler->AdvanceCurrentPosition(text_length); macro_assembler->GoTo(trace->loop_label()); return; } ASSERT(trace->stop_node() == NULL); if (!trace->is_trivial()) { trace->Flush(compiler, this); return; } ChoiceNode::Emit(compiler, trace); } intptr_t ChoiceNode::CalculatePreloadCharacters(RegExpCompiler* compiler, intptr_t eats_at_least) { intptr_t preload_characters = Utils::Minimum(static_cast(4), eats_at_least); if (compiler->macro_assembler()->CanReadUnaligned()) { bool one_byte = compiler->one_byte(); if (one_byte) { if (preload_characters > 4) preload_characters = 4; // We can't preload 3 characters because there is no machine instruction // to do that. We can't just load 4 because we could be reading // beyond the end of the string, which could cause a memory fault. if (preload_characters == 3) preload_characters = 2; } else { if (preload_characters > 2) preload_characters = 2; } } else { if (preload_characters > 1) preload_characters = 1; } return preload_characters; } // This structure is used when generating the alternatives in a choice node. It // records the way the alternative is being code generated. struct AlternativeGeneration { AlternativeGeneration() : possible_success(), expects_preload(false), after(), quick_check_details() {} BlockLabel possible_success; bool expects_preload; BlockLabel after; QuickCheckDetails quick_check_details; }; // Creates a list of AlternativeGenerations. If the list has a reasonable // size then it is on the stack, otherwise the excess is on the heap. class AlternativeGenerationList { public: explicit AlternativeGenerationList(intptr_t count) : count_(count) { ASSERT(count >= 0); if (count > kAFew) { excess_alt_gens_.reset(new AlternativeGeneration[count - kAFew]); } } AlternativeGeneration* at(intptr_t i) { ASSERT(0 <= i); ASSERT(i < count_); if (i < kAFew) { return &a_few_alt_gens_[i]; } return &excess_alt_gens_[i - kAFew]; } private: static const intptr_t kAFew = 10; intptr_t count_; AlternativeGeneration a_few_alt_gens_[kAFew]; std::unique_ptr excess_alt_gens_; DISALLOW_ALLOCATION(); DISALLOW_COPY_AND_ASSIGN(AlternativeGenerationList); }; static const int32_t kRangeEndMarker = Utf::kMaxCodePoint + 1; // The '2' variant is inclusive from and exclusive to. // This covers \s as defined in ECMA-262 5.1, 15.10.2.12, // which include WhiteSpace (7.2) or LineTerminator (7.3) values. // 0x180E has been removed from Unicode's Zs category and thus // from ECMAScript's WhiteSpace category as of Unicode 6.3. static const int32_t kSpaceRanges[] = { '\t', '\r' + 1, ' ', ' ' + 1, 0x00A0, 0x00A1, 0x1680, 0x1681, 0x2000, 0x200B, 0x2028, 0x202A, 0x202F, 0x2030, 0x205F, 0x2060, 0x3000, 0x3001, 0xFEFF, 0xFF00, kRangeEndMarker}; static const intptr_t kSpaceRangeCount = ARRAY_SIZE(kSpaceRanges); static const int32_t kWordRanges[] = { '0', '9' + 1, 'A', 'Z' + 1, '_', '_' + 1, 'a', 'z' + 1, kRangeEndMarker}; static const intptr_t kWordRangeCount = ARRAY_SIZE(kWordRanges); static const int32_t kDigitRanges[] = {'0', '9' + 1, kRangeEndMarker}; static const intptr_t kDigitRangeCount = ARRAY_SIZE(kDigitRanges); static const int32_t kSurrogateRanges[] = {0xd800, 0xe000, kRangeEndMarker}; static const intptr_t kSurrogateRangeCount = ARRAY_SIZE(kSurrogateRanges); static const int32_t kLineTerminatorRanges[] = { 0x000A, 0x000B, 0x000D, 0x000E, 0x2028, 0x202A, kRangeEndMarker}; static const intptr_t kLineTerminatorRangeCount = ARRAY_SIZE(kLineTerminatorRanges); void BoyerMoorePositionInfo::Set(intptr_t character) { SetInterval(Interval(character, character)); } void BoyerMoorePositionInfo::SetInterval(const Interval& interval) { s_ = AddRange(s_, kSpaceRanges, kSpaceRangeCount, interval); w_ = AddRange(w_, kWordRanges, kWordRangeCount, interval); d_ = AddRange(d_, kDigitRanges, kDigitRangeCount, interval); surrogate_ = AddRange(surrogate_, kSurrogateRanges, kSurrogateRangeCount, interval); if (interval.to() - interval.from() >= kMapSize - 1) { if (map_count_ != kMapSize) { map_count_ = kMapSize; for (intptr_t i = 0; i < kMapSize; i++) (*map_)[i] = true; } return; } for (intptr_t i = interval.from(); i <= interval.to(); i++) { intptr_t mod_character = (i & kMask); if (!map_->At(mod_character)) { map_count_++; (*map_)[mod_character] = true; } if (map_count_ == kMapSize) return; } } void BoyerMoorePositionInfo::SetAll() { s_ = w_ = d_ = kLatticeUnknown; if (map_count_ != kMapSize) { map_count_ = kMapSize; for (intptr_t i = 0; i < kMapSize; i++) (*map_)[i] = true; } } BoyerMooreLookahead::BoyerMooreLookahead(intptr_t length, RegExpCompiler* compiler, Zone* zone) : length_(length), compiler_(compiler) { if (compiler->one_byte()) { max_char_ = Symbols::kMaxOneCharCodeSymbol; } else { max_char_ = Utf16::kMaxCodeUnit; } bitmaps_ = new (zone) ZoneGrowableArray(length); for (intptr_t i = 0; i < length; i++) { bitmaps_->Add(new (zone) BoyerMoorePositionInfo(zone)); } } // Find the longest range of lookahead that has the fewest number of different // characters that can occur at a given position. Since we are optimizing two // different parameters at once this is a tradeoff. bool BoyerMooreLookahead::FindWorthwhileInterval(intptr_t* from, intptr_t* to) { intptr_t biggest_points = 0; // If more than 32 characters out of 128 can occur it is unlikely that we can // be lucky enough to step forwards much of the time. const intptr_t kMaxMax = 32; for (intptr_t max_number_of_chars = 4; max_number_of_chars < kMaxMax; max_number_of_chars *= 2) { biggest_points = FindBestInterval(max_number_of_chars, biggest_points, from, to); } if (biggest_points == 0) return false; return true; } // Find the highest-points range between 0 and length_ where the character // information is not too vague. 'Too vague' means that there are more than // max_number_of_chars that can occur at this position. Calculates the number // of points as the product of width-of-the-range and // probability-of-finding-one-of-the-characters, where the probability is // calculated using the frequency distribution of the sample subject string. intptr_t BoyerMooreLookahead::FindBestInterval(intptr_t max_number_of_chars, intptr_t old_biggest_points, intptr_t* from, intptr_t* to) { intptr_t biggest_points = old_biggest_points; static const intptr_t kSize = RegExpMacroAssembler::kTableSize; for (intptr_t i = 0; i < length_;) { while (i < length_ && Count(i) > max_number_of_chars) i++; if (i == length_) break; intptr_t remembered_from = i; bool union_map[kSize]; for (intptr_t j = 0; j < kSize; j++) union_map[j] = false; while (i < length_ && Count(i) <= max_number_of_chars) { BoyerMoorePositionInfo* map = bitmaps_->At(i); for (intptr_t j = 0; j < kSize; j++) union_map[j] |= map->at(j); i++; } intptr_t frequency = 0; for (intptr_t j = 0; j < kSize; j++) { if (union_map[j]) { // Add 1 to the frequency to give a small per-character boost for // the cases where our sampling is not good enough and many // characters have a frequency of zero. This means the frequency // can theoretically be up to 2*kSize though we treat it mostly as // a fraction of kSize. frequency += compiler_->frequency_collator()->Frequency(j) + 1; } } // We use the probability of skipping times the distance we are skipping to // judge the effectiveness of this. Actually we have a cut-off: By // dividing by 2 we switch off the skipping if the probability of skipping // is less than 50%. This is because the multibyte mask-and-compare // skipping in quickcheck is more likely to do well on this case. bool in_quickcheck_range = ((i - remembered_from < 4) || (compiler_->one_byte() ? remembered_from <= 4 : remembered_from <= 2)); // Called 'probability' but it is only a rough estimate and can actually // be outside the 0-kSize range. intptr_t probability = (in_quickcheck_range ? kSize / 2 : kSize) - frequency; intptr_t points = (i - remembered_from) * probability; if (points > biggest_points) { *from = remembered_from; *to = i - 1; biggest_points = points; } } return biggest_points; } // Take all the characters that will not prevent a successful match if they // occur in the subject string in the range between min_lookahead and // max_lookahead (inclusive) measured from the current position. If the // character at max_lookahead offset is not one of these characters, then we // can safely skip forwards by the number of characters in the range. intptr_t BoyerMooreLookahead::GetSkipTable( intptr_t min_lookahead, intptr_t max_lookahead, const TypedData& boolean_skip_table) { const intptr_t kSize = RegExpMacroAssembler::kTableSize; const intptr_t kSkipArrayEntry = 0; const intptr_t kDontSkipArrayEntry = 1; for (intptr_t i = 0; i < kSize; i++) { boolean_skip_table.SetUint8(i, kSkipArrayEntry); } intptr_t skip = max_lookahead + 1 - min_lookahead; for (intptr_t i = max_lookahead; i >= min_lookahead; i--) { BoyerMoorePositionInfo* map = bitmaps_->At(i); for (intptr_t j = 0; j < kSize; j++) { if (map->at(j)) { boolean_skip_table.SetUint8(j, kDontSkipArrayEntry); } } } return skip; } // See comment above on the implementation of GetSkipTable. void BoyerMooreLookahead::EmitSkipInstructions(RegExpMacroAssembler* masm) { const intptr_t kSize = RegExpMacroAssembler::kTableSize; intptr_t min_lookahead = 0; intptr_t max_lookahead = 0; if (!FindWorthwhileInterval(&min_lookahead, &max_lookahead)) return; bool found_single_character = false; intptr_t single_character = 0; for (intptr_t i = max_lookahead; i >= min_lookahead; i--) { BoyerMoorePositionInfo* map = bitmaps_->At(i); if (map->map_count() > 1 || (found_single_character && map->map_count() != 0)) { found_single_character = false; break; } for (intptr_t j = 0; j < kSize; j++) { if (map->at(j)) { found_single_character = true; single_character = j; break; } } } intptr_t lookahead_width = max_lookahead + 1 - min_lookahead; if (found_single_character && lookahead_width == 1 && max_lookahead < 3) { // The mask-compare can probably handle this better. return; } if (found_single_character) { BlockLabel cont, again; masm->BindBlock(&again); masm->LoadCurrentCharacter(max_lookahead, &cont, true); if (max_char_ > kSize) { masm->CheckCharacterAfterAnd(single_character, RegExpMacroAssembler::kTableMask, &cont); } else { masm->CheckCharacter(single_character, &cont); } masm->AdvanceCurrentPosition(lookahead_width); masm->GoTo(&again); masm->BindBlock(&cont); return; } const TypedData& boolean_skip_table = TypedData::ZoneHandle( compiler_->zone(), TypedData::New(kTypedDataUint8ArrayCid, kSize, Heap::kOld)); intptr_t skip_distance = GetSkipTable(min_lookahead, max_lookahead, boolean_skip_table); ASSERT(skip_distance != 0); BlockLabel cont, again; masm->BindBlock(&again); masm->CheckPreemption(/*is_backtrack=*/false); masm->LoadCurrentCharacter(max_lookahead, &cont, true); masm->CheckBitInTable(boolean_skip_table, &cont); masm->AdvanceCurrentPosition(skip_distance); masm->GoTo(&again); masm->BindBlock(&cont); return; } /* Code generation for choice nodes. * * We generate quick checks that do a mask and compare to eliminate a * choice. If the quick check succeeds then it jumps to the continuation to * do slow checks and check subsequent nodes. If it fails (the common case) * it falls through to the next choice. * * Here is the desired flow graph. Nodes directly below each other imply * fallthrough. Alternatives 1 and 2 have quick checks. Alternative * 3 doesn't have a quick check so we have to call the slow check. * Nodes are marked Qn for quick checks and Sn for slow checks. The entire * regexp continuation is generated directly after the Sn node, up to the * next GoTo if we decide to reuse some already generated code. Some * nodes expect preload_characters to be preloaded into the current * character register. R nodes do this preloading. Vertices are marked * F for failures and S for success (possible success in the case of quick * nodes). L, V, < and > are used as arrow heads. * * ----------> R * | * V * Q1 -----> S1 * | S / * F| / * | F/ * | / * | R * | / * V L * Q2 -----> S2 * | S / * F| / * | F/ * | / * | R * | / * V L * S3 * | * F| * | * R * | * backtrack V * <----------Q4 * \ F | * \ |S * \ F V * \-----S4 * * For greedy loops we push the current position, then generate the code that * eats the input specially in EmitGreedyLoop. The other choice (the * continuation) is generated by the normal code in EmitChoices, and steps back * in the input to the starting position when it fails to match. The loop code * looks like this (U is the unwind code that steps back in the greedy loop). * * _____ * / \ * V | * ----------> S1 | * /| | * / |S | * F/ \_____/ * / * |<----- * | \ * V |S * Q2 ---> U----->backtrack * | F / * S| / * V F / * S2--/ */ GreedyLoopState::GreedyLoopState(bool not_at_start) { counter_backtrack_trace_.set_backtrack(&label_); if (not_at_start) counter_backtrack_trace_.set_at_start(Trace::FALSE_VALUE); } void ChoiceNode::AssertGuardsMentionRegisters(Trace* trace) { #ifdef DEBUG intptr_t choice_count = alternatives_->length(); for (intptr_t i = 0; i < choice_count - 1; i++) { GuardedAlternative alternative = alternatives_->At(i); ZoneGrowableArray* guards = alternative.guards(); intptr_t guard_count = (guards == NULL) ? 0 : guards->length(); for (intptr_t j = 0; j < guard_count; j++) { ASSERT(!trace->mentions_reg(guards->At(j)->reg())); } } #endif } void ChoiceNode::SetUpPreLoad(RegExpCompiler* compiler, Trace* current_trace, PreloadState* state) { if (state->eats_at_least_ == PreloadState::kEatsAtLeastNotYetInitialized) { // Save some time by looking at most one machine word ahead. state->eats_at_least_ = EatsAtLeast(compiler->one_byte() ? 4 : 2, kRecursionBudget, current_trace->at_start() == Trace::FALSE_VALUE); } state->preload_characters_ = CalculatePreloadCharacters(compiler, state->eats_at_least_); state->preload_is_current_ = (current_trace->characters_preloaded() == state->preload_characters_); state->preload_has_checked_bounds_ = state->preload_is_current_; } void ChoiceNode::Emit(RegExpCompiler* compiler, Trace* trace) { intptr_t choice_count = alternatives_->length(); if (choice_count == 1 && alternatives_->At(0).guards() == nullptr) { alternatives_->At(0).node()->Emit(compiler, trace); return; } AssertGuardsMentionRegisters(trace); LimitResult limit_result = LimitVersions(compiler, trace); if (limit_result == DONE) return; ASSERT(limit_result == CONTINUE); // For loop nodes we already flushed (see LoopChoiceNode::Emit), but for // other choice nodes we only flush if we are out of code size budget. if (trace->flush_budget() == 0 && trace->actions() != NULL) { trace->Flush(compiler, this); return; } RecursionCheck rc(compiler); PreloadState preload; preload.init(); GreedyLoopState greedy_loop_state(not_at_start()); intptr_t text_length = GreedyLoopTextLengthForAlternative(&alternatives_->At(0)); AlternativeGenerationList alt_gens(choice_count); if (choice_count > 1 && text_length != kNodeIsTooComplexForGreedyLoops) { trace = EmitGreedyLoop(compiler, trace, &alt_gens, &preload, &greedy_loop_state, text_length); } else { // TODO(erikcorry): Delete this. We don't need this label, but it makes us // match the traces produced pre-cleanup. BlockLabel second_choice; compiler->macro_assembler()->BindBlock(&second_choice); preload.eats_at_least_ = EmitOptimizedUnanchoredSearch(compiler, trace); EmitChoices(compiler, &alt_gens, 0, trace, &preload); } // At this point we need to generate slow checks for the alternatives where // the quick check was inlined. We can recognize these because the associated // label was bound. intptr_t new_flush_budget = trace->flush_budget() / choice_count; for (intptr_t i = 0; i < choice_count; i++) { AlternativeGeneration* alt_gen = alt_gens.at(i); Trace new_trace(*trace); // If there are actions to be flushed we have to limit how many times // they are flushed. Take the budget of the parent trace and distribute // it fairly amongst the children. if (new_trace.actions() != NULL) { new_trace.set_flush_budget(new_flush_budget); } bool next_expects_preload = i == choice_count - 1 ? false : alt_gens.at(i + 1)->expects_preload; EmitOutOfLineContinuation(compiler, &new_trace, alternatives_->At(i), alt_gen, preload.preload_characters_, next_expects_preload); } } Trace* ChoiceNode::EmitGreedyLoop(RegExpCompiler* compiler, Trace* trace, AlternativeGenerationList* alt_gens, PreloadState* preload, GreedyLoopState* greedy_loop_state, intptr_t text_length) { RegExpMacroAssembler* macro_assembler = compiler->macro_assembler(); // Here we have special handling for greedy loops containing only text nodes // and other simple nodes. These are handled by pushing the current // position on the stack and then incrementing the current position each // time around the switch. On backtrack we decrement the current position // and check it against the pushed value. This avoids pushing backtrack // information for each iteration of the loop, which could take up a lot of // space. ASSERT(trace->stop_node() == NULL); macro_assembler->PushCurrentPosition(); BlockLabel greedy_match_failed; Trace greedy_match_trace; if (not_at_start()) greedy_match_trace.set_at_start(Trace::FALSE_VALUE); greedy_match_trace.set_backtrack(&greedy_match_failed); BlockLabel loop_label; macro_assembler->BindBlock(&loop_label); macro_assembler->CheckPreemption(/*is_backtrack=*/false); greedy_match_trace.set_stop_node(this); greedy_match_trace.set_loop_label(&loop_label); (*alternatives_)[0].node()->Emit(compiler, &greedy_match_trace); macro_assembler->BindBlock(&greedy_match_failed); BlockLabel second_choice; // For use in greedy matches. macro_assembler->BindBlock(&second_choice); Trace* new_trace = greedy_loop_state->counter_backtrack_trace(); EmitChoices(compiler, alt_gens, 1, new_trace, preload); macro_assembler->BindBlock(greedy_loop_state->label()); // If we have unwound to the bottom then backtrack. macro_assembler->CheckGreedyLoop(trace->backtrack()); // Otherwise try the second priority at an earlier position. macro_assembler->AdvanceCurrentPosition(-text_length); macro_assembler->GoTo(&second_choice); return new_trace; } intptr_t ChoiceNode::EmitOptimizedUnanchoredSearch(RegExpCompiler* compiler, Trace* trace) { intptr_t eats_at_least = PreloadState::kEatsAtLeastNotYetInitialized; if (alternatives_->length() != 2) return eats_at_least; GuardedAlternative alt1 = alternatives_->At(1); if (alt1.guards() != NULL && alt1.guards()->length() != 0) { return eats_at_least; } RegExpNode* eats_anything_node = alt1.node(); if (eats_anything_node->GetSuccessorOfOmnivorousTextNode(compiler) != this) { return eats_at_least; } // Really we should be creating a new trace when we execute this function, // but there is no need, because the code it generates cannot backtrack, and // we always arrive here with a trivial trace (since it's the entry to a // loop. That also implies that there are no preloaded characters, which is // good, because it means we won't be violating any assumptions by // overwriting those characters with new load instructions. ASSERT(trace->is_trivial()); RegExpMacroAssembler* macro_assembler = compiler->macro_assembler(); // At this point we know that we are at a non-greedy loop that will eat // any character one at a time. Any non-anchored regexp has such a // loop prepended to it in order to find where it starts. We look for // a pattern of the form ...abc... where we can look 6 characters ahead // and step forwards 3 if the character is not one of abc. Abc need // not be atoms, they can be any reasonably limited character class or // small alternation. BoyerMooreLookahead* bm = bm_info(false); if (bm == NULL) { eats_at_least = Utils::Minimum( kMaxLookaheadForBoyerMoore, EatsAtLeast(kMaxLookaheadForBoyerMoore, kRecursionBudget, false)); if (eats_at_least >= 1) { bm = new (Z) BoyerMooreLookahead(eats_at_least, compiler, Z); GuardedAlternative alt0 = alternatives_->At(0); alt0.node()->FillInBMInfo(0, kRecursionBudget, bm, false); } } if (bm != NULL) { bm->EmitSkipInstructions(macro_assembler); } return eats_at_least; } void ChoiceNode::EmitChoices(RegExpCompiler* compiler, AlternativeGenerationList* alt_gens, intptr_t first_choice, Trace* trace, PreloadState* preload) { RegExpMacroAssembler* macro_assembler = compiler->macro_assembler(); SetUpPreLoad(compiler, trace, preload); // For now we just call all choices one after the other. The idea ultimately // is to use the Dispatch table to try only the relevant ones. intptr_t choice_count = alternatives_->length(); intptr_t new_flush_budget = trace->flush_budget() / choice_count; for (intptr_t i = first_choice; i < choice_count; i++) { bool is_last = i == choice_count - 1; bool fall_through_on_failure = !is_last; GuardedAlternative alternative = alternatives_->At(i); AlternativeGeneration* alt_gen = alt_gens->at(i); alt_gen->quick_check_details.set_characters(preload->preload_characters_); ZoneGrowableArray* guards = alternative.guards(); intptr_t guard_count = (guards == NULL) ? 0 : guards->length(); Trace new_trace(*trace); new_trace.set_characters_preloaded( preload->preload_is_current_ ? preload->preload_characters_ : 0); if (preload->preload_has_checked_bounds_) { new_trace.set_bound_checked_up_to(preload->preload_characters_); } new_trace.quick_check_performed()->Clear(); if (not_at_start_) new_trace.set_at_start(Trace::FALSE_VALUE); if (!is_last) { new_trace.set_backtrack(&alt_gen->after); } alt_gen->expects_preload = preload->preload_is_current_; bool generate_full_check_inline = false; if (kRegexpOptimization && try_to_emit_quick_check_for_alternative(i == 0) && alternative.node()->EmitQuickCheck( compiler, trace, &new_trace, preload->preload_has_checked_bounds_, &alt_gen->possible_success, &alt_gen->quick_check_details, fall_through_on_failure)) { // Quick check was generated for this choice. preload->preload_is_current_ = true; preload->preload_has_checked_bounds_ = true; // If we generated the quick check to fall through on possible success, // we now need to generate the full check inline. if (!fall_through_on_failure) { macro_assembler->BindBlock(&alt_gen->possible_success); new_trace.set_quick_check_performed(&alt_gen->quick_check_details); new_trace.set_characters_preloaded(preload->preload_characters_); new_trace.set_bound_checked_up_to(preload->preload_characters_); generate_full_check_inline = true; } } else if (alt_gen->quick_check_details.cannot_match()) { if (!fall_through_on_failure) { macro_assembler->GoTo(trace->backtrack()); } continue; } else { // No quick check was generated. Put the full code here. // If this is not the first choice then there could be slow checks from // previous cases that go here when they fail. There's no reason to // insist that they preload characters since the slow check we are about // to generate probably can't use it. if (i != first_choice) { alt_gen->expects_preload = false; new_trace.InvalidateCurrentCharacter(); } generate_full_check_inline = true; } if (generate_full_check_inline) { if (new_trace.actions() != NULL) { new_trace.set_flush_budget(new_flush_budget); } for (intptr_t j = 0; j < guard_count; j++) { GenerateGuard(macro_assembler, guards->At(j), &new_trace); } alternative.node()->Emit(compiler, &new_trace); preload->preload_is_current_ = false; } macro_assembler->BindBlock(&alt_gen->after); } } void ChoiceNode::EmitOutOfLineContinuation(RegExpCompiler* compiler, Trace* trace, GuardedAlternative alternative, AlternativeGeneration* alt_gen, intptr_t preload_characters, bool next_expects_preload) { if (!alt_gen->possible_success.IsLinked()) return; RegExpMacroAssembler* macro_assembler = compiler->macro_assembler(); macro_assembler->BindBlock(&alt_gen->possible_success); Trace out_of_line_trace(*trace); out_of_line_trace.set_characters_preloaded(preload_characters); out_of_line_trace.set_quick_check_performed(&alt_gen->quick_check_details); if (not_at_start_) out_of_line_trace.set_at_start(Trace::FALSE_VALUE); ZoneGrowableArray* guards = alternative.guards(); intptr_t guard_count = (guards == NULL) ? 0 : guards->length(); if (next_expects_preload) { BlockLabel reload_current_char; out_of_line_trace.set_backtrack(&reload_current_char); for (intptr_t j = 0; j < guard_count; j++) { GenerateGuard(macro_assembler, guards->At(j), &out_of_line_trace); } alternative.node()->Emit(compiler, &out_of_line_trace); macro_assembler->BindBlock(&reload_current_char); // Reload the current character, since the next quick check expects that. // We don't need to check bounds here because we only get into this // code through a quick check which already did the checked load. macro_assembler->LoadCurrentCharacter(trace->cp_offset(), NULL, false, preload_characters); macro_assembler->GoTo(&(alt_gen->after)); } else { out_of_line_trace.set_backtrack(&(alt_gen->after)); for (intptr_t j = 0; j < guard_count; j++) { GenerateGuard(macro_assembler, guards->At(j), &out_of_line_trace); } alternative.node()->Emit(compiler, &out_of_line_trace); } } void ActionNode::Emit(RegExpCompiler* compiler, Trace* trace) { RegExpMacroAssembler* assembler = compiler->macro_assembler(); LimitResult limit_result = LimitVersions(compiler, trace); if (limit_result == DONE) return; ASSERT(limit_result == CONTINUE); RecursionCheck rc(compiler); switch (action_type_) { case STORE_POSITION: { Trace::DeferredCapture new_capture(data_.u_position_register.reg, data_.u_position_register.is_capture, trace); Trace new_trace = *trace; new_trace.add_action(&new_capture); on_success()->Emit(compiler, &new_trace); break; } case INCREMENT_REGISTER: { Trace::DeferredIncrementRegister new_increment( data_.u_increment_register.reg); Trace new_trace = *trace; new_trace.add_action(&new_increment); on_success()->Emit(compiler, &new_trace); break; } case SET_REGISTER: { Trace::DeferredSetRegister new_set(data_.u_store_register.reg, data_.u_store_register.value); Trace new_trace = *trace; new_trace.add_action(&new_set); on_success()->Emit(compiler, &new_trace); break; } case CLEAR_CAPTURES: { Trace::DeferredClearCaptures new_capture(Interval( data_.u_clear_captures.range_from, data_.u_clear_captures.range_to)); Trace new_trace = *trace; new_trace.add_action(&new_capture); on_success()->Emit(compiler, &new_trace); break; } case BEGIN_SUBMATCH: if (!trace->is_trivial()) { trace->Flush(compiler, this); } else { assembler->WriteCurrentPositionToRegister( data_.u_submatch.current_position_register, 0); assembler->WriteStackPointerToRegister( data_.u_submatch.stack_pointer_register); on_success()->Emit(compiler, trace); } break; case EMPTY_MATCH_CHECK: { intptr_t start_pos_reg = data_.u_empty_match_check.start_register; intptr_t stored_pos = 0; intptr_t rep_reg = data_.u_empty_match_check.repetition_register; bool has_minimum = (rep_reg != RegExpCompiler::kNoRegister); bool know_dist = trace->GetStoredPosition(start_pos_reg, &stored_pos); if (know_dist && !has_minimum && stored_pos == trace->cp_offset()) { // If we know we haven't advanced and there is no minimum we // can just backtrack immediately. assembler->GoTo(trace->backtrack()); } else if (know_dist && stored_pos < trace->cp_offset()) { // If we know we've advanced we can generate the continuation // immediately. on_success()->Emit(compiler, trace); } else if (!trace->is_trivial()) { trace->Flush(compiler, this); } else { BlockLabel skip_empty_check; // If we have a minimum number of repetitions we check the current // number first and skip the empty check if it's not enough. if (has_minimum) { intptr_t limit = data_.u_empty_match_check.repetition_limit; assembler->IfRegisterLT(rep_reg, limit, &skip_empty_check); } // If the match is empty we bail out, otherwise we fall through // to the on-success continuation. assembler->IfRegisterEqPos(data_.u_empty_match_check.start_register, trace->backtrack()); assembler->BindBlock(&skip_empty_check); on_success()->Emit(compiler, trace); } break; } case POSITIVE_SUBMATCH_SUCCESS: { if (!trace->is_trivial()) { trace->Flush(compiler, this); return; } assembler->ReadCurrentPositionFromRegister( data_.u_submatch.current_position_register); assembler->ReadStackPointerFromRegister( data_.u_submatch.stack_pointer_register); intptr_t clear_register_count = data_.u_submatch.clear_register_count; if (clear_register_count == 0) { on_success()->Emit(compiler, trace); return; } intptr_t clear_registers_from = data_.u_submatch.clear_register_from; BlockLabel clear_registers_backtrack; Trace new_trace = *trace; new_trace.set_backtrack(&clear_registers_backtrack); on_success()->Emit(compiler, &new_trace); assembler->BindBlock(&clear_registers_backtrack); intptr_t clear_registers_to = clear_registers_from + clear_register_count - 1; assembler->ClearRegisters(clear_registers_from, clear_registers_to); ASSERT(trace->backtrack() == NULL); assembler->Backtrack(); return; } default: UNREACHABLE(); } } void BackReferenceNode::Emit(RegExpCompiler* compiler, Trace* trace) { RegExpMacroAssembler* assembler = compiler->macro_assembler(); if (!trace->is_trivial()) { trace->Flush(compiler, this); return; } LimitResult limit_result = LimitVersions(compiler, trace); if (limit_result == DONE) return; ASSERT(limit_result == CONTINUE); RecursionCheck rc(compiler); ASSERT(start_reg_ + 1 == end_reg_); if (flags_.IgnoreCase()) { assembler->CheckNotBackReferenceIgnoreCase( start_reg_, read_backward(), flags_.IsUnicode(), trace->backtrack()); } else { assembler->CheckNotBackReference(start_reg_, read_backward(), trace->backtrack()); } // We are going to advance backward, so we may end up at the start. if (read_backward()) trace->set_at_start(Trace::UNKNOWN); // Check that the back reference does not end inside a surrogate pair. if (flags_.IsUnicode() && !compiler->one_byte()) { assembler->CheckNotInSurrogatePair(trace->cp_offset(), trace->backtrack()); } on_success()->Emit(compiler, trace); } // ------------------------------------------------------------------- // Dot/dotty output #ifdef DEBUG class DotPrinter : public NodeVisitor { public: explicit DotPrinter(bool ignore_case) {} void PrintNode(const char* label, RegExpNode* node); void Visit(RegExpNode* node); void PrintAttributes(RegExpNode* from); void PrintOnFailure(RegExpNode* from, RegExpNode* to); #define DECLARE_VISIT(Type) virtual void Visit##Type(Type##Node* that); FOR_EACH_NODE_TYPE(DECLARE_VISIT) #undef DECLARE_VISIT }; void DotPrinter::PrintNode(const char* label, RegExpNode* node) { OS::PrintErr("digraph G {\n graph [label=\""); for (intptr_t i = 0; label[i] != '\0'; i++) { switch (label[i]) { case '\\': OS::PrintErr("\\\\"); break; case '"': OS::PrintErr("\""); break; default: OS::PrintErr("%c", label[i]); break; } } OS::PrintErr("\"];\n"); Visit(node); OS::PrintErr("}\n"); } void DotPrinter::Visit(RegExpNode* node) { if (node->info()->visited) return; node->info()->visited = true; node->Accept(this); } void DotPrinter::PrintOnFailure(RegExpNode* from, RegExpNode* on_failure) { OS::PrintErr(" n%p -> n%p [style=dotted];\n", from, on_failure); Visit(on_failure); } class AttributePrinter : public ValueObject { public: AttributePrinter() : first_(true) {} void PrintSeparator() { if (first_) { first_ = false; } else { OS::PrintErr("|"); } } void PrintBit(const char* name, bool value) { if (!value) return; PrintSeparator(); OS::PrintErr("{%s}", name); } void PrintPositive(const char* name, intptr_t value) { if (value < 0) return; PrintSeparator(); OS::PrintErr("{%s|%" Pd "}", name, value); } private: bool first_; }; void DotPrinter::PrintAttributes(RegExpNode* that) { OS::PrintErr( " a%p [shape=Mrecord, color=grey, fontcolor=grey, " "margin=0.1, fontsize=10, label=\"{", that); AttributePrinter printer; NodeInfo* info = that->info(); printer.PrintBit("NI", info->follows_newline_interest); printer.PrintBit("WI", info->follows_word_interest); printer.PrintBit("SI", info->follows_start_interest); BlockLabel* label = that->label(); if (label->IsBound()) printer.PrintPositive("@", label->Position()); OS::PrintErr( "}\"];\n" " a%p -> n%p [style=dashed, color=grey, arrowhead=none];\n", that, that); } void DotPrinter::VisitChoice(ChoiceNode* that) { OS::PrintErr(" n%p [shape=Mrecord, label=\"?\"];\n", that); for (intptr_t i = 0; i < that->alternatives()->length(); i++) { GuardedAlternative alt = that->alternatives()->At(i); OS::PrintErr(" n%p -> n%p", that, alt.node()); } for (intptr_t i = 0; i < that->alternatives()->length(); i++) { GuardedAlternative alt = that->alternatives()->At(i); alt.node()->Accept(this); } } void DotPrinter::VisitText(TextNode* that) { OS::PrintErr(" n%p [label=\"", that); for (intptr_t i = 0; i < that->elements()->length(); i++) { if (i > 0) OS::PrintErr(" "); TextElement elm = that->elements()->At(i); switch (elm.text_type()) { case TextElement::ATOM: { ZoneGrowableArray* data = elm.atom()->data(); for (intptr_t i = 0; i < data->length(); i++) { OS::PrintErr("%c", static_cast(data->At(i))); } break; } case TextElement::CHAR_CLASS: { RegExpCharacterClass* node = elm.char_class(); OS::PrintErr("["); if (node->is_negated()) OS::PrintErr("^"); for (intptr_t j = 0; j < node->ranges()->length(); j++) { CharacterRange range = node->ranges()->At(j); PrintUtf16(range.from()); OS::PrintErr("-"); PrintUtf16(range.to()); } OS::PrintErr("]"); break; } default: UNREACHABLE(); } } OS::PrintErr("\", shape=box, peripheries=2];\n"); PrintAttributes(that); OS::PrintErr(" n%p -> n%p;\n", that, that->on_success()); Visit(that->on_success()); } void DotPrinter::VisitBackReference(BackReferenceNode* that) { OS::PrintErr(" n%p [label=\"$%" Pd "..$%" Pd "\", shape=doubleoctagon];\n", that, that->start_register(), that->end_register()); PrintAttributes(that); OS::PrintErr(" n%p -> n%p;\n", that, that->on_success()); Visit(that->on_success()); } void DotPrinter::VisitEnd(EndNode* that) { OS::PrintErr(" n%p [style=bold, shape=point];\n", that); PrintAttributes(that); } void DotPrinter::VisitAssertion(AssertionNode* that) { OS::PrintErr(" n%p [", that); switch (that->assertion_type()) { case AssertionNode::AT_END: OS::PrintErr("label=\"$\", shape=septagon"); break; case AssertionNode::AT_START: OS::PrintErr("label=\"^\", shape=septagon"); break; case AssertionNode::AT_BOUNDARY: OS::PrintErr("label=\"\\b\", shape=septagon"); break; case AssertionNode::AT_NON_BOUNDARY: OS::PrintErr("label=\"\\B\", shape=septagon"); break; case AssertionNode::AFTER_NEWLINE: OS::PrintErr("label=\"(?<=\\n)\", shape=septagon"); break; } OS::PrintErr("];\n"); PrintAttributes(that); RegExpNode* successor = that->on_success(); OS::PrintErr(" n%p -> n%p;\n", that, successor); Visit(successor); } void DotPrinter::VisitAction(ActionNode* that) { OS::PrintErr(" n%p [", that); switch (that->action_type_) { case ActionNode::SET_REGISTER: OS::PrintErr("label=\"$%" Pd ":=%" Pd "\", shape=octagon", that->data_.u_store_register.reg, that->data_.u_store_register.value); break; case ActionNode::INCREMENT_REGISTER: OS::PrintErr("label=\"$%" Pd "++\", shape=octagon", that->data_.u_increment_register.reg); break; case ActionNode::STORE_POSITION: OS::PrintErr("label=\"$%" Pd ":=$pos\", shape=octagon", that->data_.u_position_register.reg); break; case ActionNode::BEGIN_SUBMATCH: OS::PrintErr("label=\"$%" Pd ":=$pos,begin\", shape=septagon", that->data_.u_submatch.current_position_register); break; case ActionNode::POSITIVE_SUBMATCH_SUCCESS: OS::PrintErr("label=\"escape\", shape=septagon"); break; case ActionNode::EMPTY_MATCH_CHECK: OS::PrintErr("label=\"$%" Pd "=$pos?,$%" Pd "<%" Pd "?\", shape=septagon", that->data_.u_empty_match_check.start_register, that->data_.u_empty_match_check.repetition_register, that->data_.u_empty_match_check.repetition_limit); break; case ActionNode::CLEAR_CAPTURES: { OS::PrintErr("label=\"clear $%" Pd " to $%" Pd "\", shape=septagon", that->data_.u_clear_captures.range_from, that->data_.u_clear_captures.range_to); break; } } OS::PrintErr("];\n"); PrintAttributes(that); RegExpNode* successor = that->on_success(); OS::PrintErr(" n%p -> n%p;\n", that, successor); Visit(successor); } void RegExpEngine::DotPrint(const char* label, RegExpNode* node, bool ignore_case) { DotPrinter printer(ignore_case); printer.PrintNode(label, node); } #endif // DEBUG // ------------------------------------------------------------------- // Tree to graph conversion // The zone in which we allocate graph nodes. #define OZ (on_success->zone()) RegExpNode* RegExpAtom::ToNode(RegExpCompiler* compiler, RegExpNode* on_success) { ZoneGrowableArray* elms = new (OZ) ZoneGrowableArray(1); elms->Add(TextElement::Atom(this)); return new (OZ) TextNode(elms, compiler->read_backward(), on_success); } RegExpNode* RegExpText::ToNode(RegExpCompiler* compiler, RegExpNode* on_success) { ZoneGrowableArray* elms = new (OZ) ZoneGrowableArray(1); for (intptr_t i = 0; i < elements()->length(); i++) { elms->Add(elements()->At(i)); } return new (OZ) TextNode(elms, compiler->read_backward(), on_success); } static bool CompareInverseRanges(ZoneGrowableArray* ranges, const int32_t* special_class, intptr_t length) { length--; // Remove final kRangeEndMarker. ASSERT(special_class[length] == kRangeEndMarker); ASSERT(ranges->length() != 0); ASSERT(length != 0); ASSERT(special_class[0] != 0); if (ranges->length() != (length >> 1) + 1) { return false; } CharacterRange range = ranges->At(0); if (range.from() != 0) { return false; } for (intptr_t i = 0; i < length; i += 2) { if (special_class[i] != (range.to() + 1)) { return false; } range = ranges->At((i >> 1) + 1); if (special_class[i + 1] != range.from()) { return false; } } if (range.to() != Utf::kMaxCodePoint) { return false; } return true; } static bool CompareRanges(ZoneGrowableArray* ranges, const int32_t* special_class, intptr_t length) { length--; // Remove final kRangeEndMarker. ASSERT(special_class[length] == kRangeEndMarker); if (ranges->length() * 2 != length) { return false; } for (intptr_t i = 0; i < length; i += 2) { CharacterRange range = ranges->At(i >> 1); if (range.from() != special_class[i] || range.to() != special_class[i + 1] - 1) { return false; } } return true; } bool RegExpCharacterClass::is_standard() { // TODO(lrn): Remove need for this function, by not throwing away information // along the way. if (is_negated()) { return false; } if (set_.is_standard()) { return true; } if (CompareRanges(set_.ranges(), kSpaceRanges, kSpaceRangeCount)) { set_.set_standard_set_type('s'); return true; } if (CompareInverseRanges(set_.ranges(), kSpaceRanges, kSpaceRangeCount)) { set_.set_standard_set_type('S'); return true; } if (CompareInverseRanges(set_.ranges(), kLineTerminatorRanges, kLineTerminatorRangeCount)) { set_.set_standard_set_type('.'); return true; } if (CompareRanges(set_.ranges(), kLineTerminatorRanges, kLineTerminatorRangeCount)) { set_.set_standard_set_type('n'); return true; } if (CompareRanges(set_.ranges(), kWordRanges, kWordRangeCount)) { set_.set_standard_set_type('w'); return true; } if (CompareInverseRanges(set_.ranges(), kWordRanges, kWordRangeCount)) { set_.set_standard_set_type('W'); return true; } return false; } UnicodeRangeSplitter::UnicodeRangeSplitter( Zone* zone, ZoneGrowableArray* base) : zone_(zone), table_(zone), bmp_(nullptr), lead_surrogates_(nullptr), trail_surrogates_(nullptr), non_bmp_(nullptr) { // The unicode range splitter categorizes given character ranges into: // - Code points from the BMP representable by one code unit. // - Code points outside the BMP that need to be split into surrogate pairs. // - Lone lead surrogates. // - Lone trail surrogates. // Lone surrogates are valid code points, even though no actual characters. // They require special matching to make sure we do not split surrogate pairs. // We use the dispatch table to accomplish this. The base range is split up // by the table by the overlay ranges, and the Call callback is used to // filter and collect ranges for each category. for (intptr_t i = 0; i < base->length(); i++) { table_.AddRange(base->At(i), kBase, zone_); } // Add overlay ranges. table_.AddRange(CharacterRange::Range(0, Utf16::kLeadSurrogateStart - 1), kBmpCodePoints, zone_); table_.AddRange(CharacterRange::Range(Utf16::kLeadSurrogateStart, Utf16::kLeadSurrogateEnd), kLeadSurrogates, zone_); table_.AddRange(CharacterRange::Range(Utf16::kTrailSurrogateStart, Utf16::kTrailSurrogateEnd), kTrailSurrogates, zone_); table_.AddRange( CharacterRange::Range(Utf16::kTrailSurrogateEnd + 1, Utf16::kMaxCodeUnit), kBmpCodePoints, zone_); table_.AddRange( CharacterRange::Range(Utf16::kMaxCodeUnit + 1, Utf::kMaxCodePoint), kNonBmpCodePoints, zone_); table_.ForEach(this); } void UnicodeRangeSplitter::Call(uint32_t from, DispatchTable::Entry entry) { OutSet* outset = entry.out_set(); if (!outset->Get(kBase)) return; ZoneGrowableArray** target = nullptr; if (outset->Get(kBmpCodePoints)) { target = &bmp_; } else if (outset->Get(kLeadSurrogates)) { target = &lead_surrogates_; } else if (outset->Get(kTrailSurrogates)) { target = &trail_surrogates_; } else { ASSERT(outset->Get(kNonBmpCodePoints)); target = &non_bmp_; } if (*target == nullptr) { *target = new (zone_) ZoneGrowableArray(2); } (*target)->Add(CharacterRange::Range(entry.from(), entry.to())); } void AddBmpCharacters(RegExpCompiler* compiler, ChoiceNode* result, RegExpNode* on_success, UnicodeRangeSplitter* splitter) { ZoneGrowableArray* bmp = splitter->bmp(); if (bmp == nullptr) return; result->AddAlternative(GuardedAlternative(TextNode::CreateForCharacterRanges( bmp, compiler->read_backward(), on_success, RegExpFlags()))); } void AddNonBmpSurrogatePairs(RegExpCompiler* compiler, ChoiceNode* result, RegExpNode* on_success, UnicodeRangeSplitter* splitter) { ZoneGrowableArray* non_bmp = splitter->non_bmp(); if (non_bmp == nullptr) return; ASSERT(!compiler->one_byte()); CharacterRange::Canonicalize(non_bmp); for (int i = 0; i < non_bmp->length(); i++) { // Match surrogate pair. // E.g. [\u10005-\u11005] becomes // \ud800[\udc05-\udfff]| // [\ud801-\ud803][\udc00-\udfff]| // \ud804[\udc00-\udc05] uint32_t from = non_bmp->At(i).from(); uint32_t to = non_bmp->At(i).to(); uint16_t from_points[2]; Utf16::Encode(from, from_points); uint16_t to_points[2]; Utf16::Encode(to, to_points); if (from_points[0] == to_points[0]) { // The lead surrogate is the same. result->AddAlternative( GuardedAlternative(TextNode::CreateForSurrogatePair( CharacterRange::Singleton(from_points[0]), CharacterRange::Range(from_points[1], to_points[1]), compiler->read_backward(), on_success, RegExpFlags()))); } else { if (from_points[1] != Utf16::kTrailSurrogateStart) { // Add [from_l][from_t-\udfff] result->AddAlternative( GuardedAlternative(TextNode::CreateForSurrogatePair( CharacterRange::Singleton(from_points[0]), CharacterRange::Range(from_points[1], Utf16::kTrailSurrogateEnd), compiler->read_backward(), on_success, RegExpFlags()))); from_points[0]++; } if (to_points[1] != Utf16::kTrailSurrogateEnd) { // Add [to_l][\udc00-to_t] result->AddAlternative( GuardedAlternative(TextNode::CreateForSurrogatePair( CharacterRange::Singleton(to_points[0]), CharacterRange::Range(Utf16::kTrailSurrogateStart, to_points[1]), compiler->read_backward(), on_success, RegExpFlags()))); to_points[0]--; } if (from_points[0] <= to_points[0]) { // Add [from_l-to_l][\udc00-\udfff] result->AddAlternative( GuardedAlternative(TextNode::CreateForSurrogatePair( CharacterRange::Range(from_points[0], to_points[0]), CharacterRange::Range(Utf16::kTrailSurrogateStart, Utf16::kTrailSurrogateEnd), compiler->read_backward(), on_success, RegExpFlags()))); } } } } RegExpNode* NegativeLookaroundAgainstReadDirectionAndMatch( RegExpCompiler* compiler, ZoneGrowableArray* lookbehind, ZoneGrowableArray* match, RegExpNode* on_success, bool read_backward, RegExpFlags flags) { RegExpNode* match_node = TextNode::CreateForCharacterRanges( match, read_backward, on_success, flags); int stack_register = compiler->UnicodeLookaroundStackRegister(); int position_register = compiler->UnicodeLookaroundPositionRegister(); RegExpLookaround::Builder lookaround(false, match_node, stack_register, position_register); RegExpNode* negative_match = TextNode::CreateForCharacterRanges( lookbehind, !read_backward, lookaround.on_match_success(), flags); return lookaround.ForMatch(negative_match); } RegExpNode* MatchAndNegativeLookaroundInReadDirection( RegExpCompiler* compiler, ZoneGrowableArray* match, ZoneGrowableArray* lookahead, RegExpNode* on_success, bool read_backward, RegExpFlags flags) { int stack_register = compiler->UnicodeLookaroundStackRegister(); int position_register = compiler->UnicodeLookaroundPositionRegister(); RegExpLookaround::Builder lookaround(false, on_success, stack_register, position_register); RegExpNode* negative_match = TextNode::CreateForCharacterRanges( lookahead, read_backward, lookaround.on_match_success(), flags); return TextNode::CreateForCharacterRanges( match, read_backward, lookaround.ForMatch(negative_match), flags); } void AddLoneLeadSurrogates(RegExpCompiler* compiler, ChoiceNode* result, RegExpNode* on_success, UnicodeRangeSplitter* splitter) { auto lead_surrogates = splitter->lead_surrogates(); if (lead_surrogates == nullptr) return; // E.g. \ud801 becomes \ud801(?![\udc00-\udfff]). auto trail_surrogates = CharacterRange::List( on_success->zone(), CharacterRange::Range(Utf16::kTrailSurrogateStart, Utf16::kTrailSurrogateEnd)); RegExpNode* match; if (compiler->read_backward()) { // Reading backward. Assert that reading forward, there is no trail // surrogate, and then backward match the lead surrogate. match = NegativeLookaroundAgainstReadDirectionAndMatch( compiler, trail_surrogates, lead_surrogates, on_success, true, RegExpFlags()); } else { // Reading forward. Forward match the lead surrogate and assert that // no trail surrogate follows. match = MatchAndNegativeLookaroundInReadDirection( compiler, lead_surrogates, trail_surrogates, on_success, false, RegExpFlags()); } result->AddAlternative(GuardedAlternative(match)); } void AddLoneTrailSurrogates(RegExpCompiler* compiler, ChoiceNode* result, RegExpNode* on_success, UnicodeRangeSplitter* splitter) { auto trail_surrogates = splitter->trail_surrogates(); if (trail_surrogates == nullptr) return; // E.g. \udc01 becomes (?zone(), CharacterRange::Range(Utf16::kLeadSurrogateStart, Utf16::kLeadSurrogateEnd)); RegExpNode* match; if (compiler->read_backward()) { // Reading backward. Backward match the trail surrogate and assert that no // lead surrogate precedes it. match = MatchAndNegativeLookaroundInReadDirection( compiler, trail_surrogates, lead_surrogates, on_success, true, RegExpFlags()); } else { // Reading forward. Assert that reading backward, there is no lead // surrogate, and then forward match the trail surrogate. match = NegativeLookaroundAgainstReadDirectionAndMatch( compiler, lead_surrogates, trail_surrogates, on_success, false, RegExpFlags()); } result->AddAlternative(GuardedAlternative(match)); } RegExpNode* UnanchoredAdvance(RegExpCompiler* compiler, RegExpNode* on_success) { // This implements ES2015 21.2.5.2.3, AdvanceStringIndex. ASSERT(!compiler->read_backward()); // Advance any character. If the character happens to be a lead surrogate and // we advanced into the middle of a surrogate pair, it will work out, as // nothing will match from there. We will have to advance again, consuming // the associated trail surrogate. auto range = CharacterRange::List( on_success->zone(), CharacterRange::Range(0, Utf16::kMaxCodeUnit)); return TextNode::CreateForCharacterRanges(range, false, on_success, RegExpFlags()); } void AddUnicodeCaseEquivalents(ZoneGrowableArray* ranges) { ASSERT(CharacterRange::IsCanonical(ranges)); // Micro-optimization to avoid passing large ranges to UnicodeSet::closeOver. // See also https://crbug.com/v8/6727. // TODO(sstrickl): This only covers the special case of the {0,0x10FFFF} // range, which we use frequently internally. But large ranges can also easily // be created by the user. We might want to have a more general caching // mechanism for such ranges. if (ranges->length() == 1 && ranges->At(0).IsEverything(Utf::kMaxCodePoint)) { return; } icu::UnicodeSet set; for (int i = 0; i < ranges->length(); i++) { set.add(ranges->At(i).from(), ranges->At(i).to()); } ranges->Clear(); set.closeOver(USET_CASE_INSENSITIVE); // Full case mapping map single characters to multiple characters. // Those are represented as strings in the set. Remove them so that // we end up with only simple and common case mappings. set.removeAllStrings(); for (int i = 0; i < set.getRangeCount(); i++) { ranges->Add( CharacterRange::Range(set.getRangeStart(i), set.getRangeEnd(i))); } // No errors and everything we collected have been ranges. CharacterRange::Canonicalize(ranges); } RegExpNode* RegExpCharacterClass::ToNode(RegExpCompiler* compiler, RegExpNode* on_success) { set_.Canonicalize(); ZoneGrowableArray* ranges = this->ranges(); if (flags_.NeedsUnicodeCaseEquivalents()) { AddUnicodeCaseEquivalents(ranges); } if (flags_.IsUnicode() && !compiler->one_byte() && !contains_split_surrogate()) { if (is_negated()) { ZoneGrowableArray* negated = new ZoneGrowableArray(2); CharacterRange::Negate(ranges, negated); ranges = negated; } if (ranges->length() == 0) { RegExpCharacterClass* fail = new RegExpCharacterClass(ranges, RegExpFlags()); return new TextNode(fail, compiler->read_backward(), on_success); } if (standard_type() == '*') { return UnanchoredAdvance(compiler, on_success); } else { ChoiceNode* result = new (OZ) ChoiceNode(2, OZ); UnicodeRangeSplitter splitter(OZ, ranges); AddBmpCharacters(compiler, result, on_success, &splitter); AddNonBmpSurrogatePairs(compiler, result, on_success, &splitter); AddLoneLeadSurrogates(compiler, result, on_success, &splitter); AddLoneTrailSurrogates(compiler, result, on_success, &splitter); return result; } } else { return new TextNode(this, compiler->read_backward(), on_success); } return new (OZ) TextNode(this, compiler->read_backward(), on_success); } RegExpNode* RegExpDisjunction::ToNode(RegExpCompiler* compiler, RegExpNode* on_success) { ZoneGrowableArray* alternatives = this->alternatives(); intptr_t length = alternatives->length(); ChoiceNode* result = new (OZ) ChoiceNode(length, OZ); for (intptr_t i = 0; i < length; i++) { GuardedAlternative alternative( alternatives->At(i)->ToNode(compiler, on_success)); result->AddAlternative(alternative); } return result; } RegExpNode* RegExpQuantifier::ToNode(RegExpCompiler* compiler, RegExpNode* on_success) { return ToNode(min(), max(), is_greedy(), body(), compiler, on_success); } // Scoped object to keep track of how much we unroll quantifier loops in the // regexp graph generator. class RegExpExpansionLimiter : public ValueObject { public: static const intptr_t kMaxExpansionFactor = 6; RegExpExpansionLimiter(RegExpCompiler* compiler, intptr_t factor) : compiler_(compiler), saved_expansion_factor_(compiler->current_expansion_factor()), ok_to_expand_(saved_expansion_factor_ <= kMaxExpansionFactor) { ASSERT(factor > 0); if (ok_to_expand_) { if (factor > kMaxExpansionFactor) { // Avoid integer overflow of the current expansion factor. ok_to_expand_ = false; compiler->set_current_expansion_factor(kMaxExpansionFactor + 1); } else { intptr_t new_factor = saved_expansion_factor_ * factor; ok_to_expand_ = (new_factor <= kMaxExpansionFactor); compiler->set_current_expansion_factor(new_factor); } } } ~RegExpExpansionLimiter() { compiler_->set_current_expansion_factor(saved_expansion_factor_); } bool ok_to_expand() { return ok_to_expand_; } private: RegExpCompiler* compiler_; intptr_t saved_expansion_factor_; bool ok_to_expand_; DISALLOW_IMPLICIT_CONSTRUCTORS(RegExpExpansionLimiter); }; RegExpNode* RegExpQuantifier::ToNode(intptr_t min, intptr_t max, bool is_greedy, RegExpTree* body, RegExpCompiler* compiler, RegExpNode* on_success, bool not_at_start) { // x{f, t} becomes this: // // (r++)<-. // | ` // | (x) // v ^ // (r=0)-->(?)---/ [if r < t] // | // [if r >= f] \----> ... // // 15.10.2.5 RepeatMatcher algorithm. // The parser has already eliminated the case where max is 0. In the case // where max_match is zero the parser has removed the quantifier if min was // > 0 and removed the atom if min was 0. See AddQuantifierToAtom. // If we know that we cannot match zero length then things are a little // simpler since we don't need to make the special zero length match check // from step 2.1. If the min and max are small we can unroll a little in // this case. // Unroll (foo)+ and (foo){3,} static const intptr_t kMaxUnrolledMinMatches = 3; // Unroll (foo)? and (foo){x,3} static const intptr_t kMaxUnrolledMaxMatches = 3; if (max == 0) return on_success; // This can happen due to recursion. bool body_can_be_empty = (body->min_match() == 0); intptr_t body_start_reg = RegExpCompiler::kNoRegister; Interval capture_registers = body->CaptureRegisters(); bool needs_capture_clearing = !capture_registers.is_empty(); Zone* zone = compiler->zone(); if (body_can_be_empty) { body_start_reg = compiler->AllocateRegister(); } else if (kRegexpOptimization && !needs_capture_clearing) { // Only unroll if there are no captures and the body can't be // empty. { RegExpExpansionLimiter limiter(compiler, min + ((max != min) ? 1 : 0)); if (min > 0 && min <= kMaxUnrolledMinMatches && limiter.ok_to_expand()) { intptr_t new_max = (max == kInfinity) ? max : max - min; // Recurse once to get the loop or optional matches after the fixed // ones. RegExpNode* answer = ToNode(0, new_max, is_greedy, body, compiler, on_success, true); // Unroll the forced matches from 0 to min. This can cause chains of // TextNodes (which the parser does not generate). These should be // combined if it turns out they hinder good code generation. for (intptr_t i = 0; i < min; i++) { answer = body->ToNode(compiler, answer); } return answer; } } if (max <= kMaxUnrolledMaxMatches && min == 0) { ASSERT(max > 0); // Due to the 'if' above. RegExpExpansionLimiter limiter(compiler, max); if (limiter.ok_to_expand()) { // Unroll the optional matches up to max. RegExpNode* answer = on_success; for (intptr_t i = 0; i < max; i++) { ChoiceNode* alternation = new (zone) ChoiceNode(2, zone); if (is_greedy) { alternation->AddAlternative( GuardedAlternative(body->ToNode(compiler, answer))); alternation->AddAlternative(GuardedAlternative(on_success)); } else { alternation->AddAlternative(GuardedAlternative(on_success)); alternation->AddAlternative( GuardedAlternative(body->ToNode(compiler, answer))); } answer = alternation; if (not_at_start && !compiler->read_backward()) { alternation->set_not_at_start(); } } return answer; } } } bool has_min = min > 0; bool has_max = max < RegExpTree::kInfinity; bool needs_counter = has_min || has_max; intptr_t reg_ctr = needs_counter ? compiler->AllocateRegister() : RegExpCompiler::kNoRegister; LoopChoiceNode* center = new (zone) LoopChoiceNode(body->min_match() == 0, compiler->read_backward(), zone); if (not_at_start && !compiler->read_backward()) center->set_not_at_start(); RegExpNode* loop_return = needs_counter ? static_cast( ActionNode::IncrementRegister(reg_ctr, center)) : static_cast(center); if (body_can_be_empty) { // If the body can be empty we need to check if it was and then // backtrack. loop_return = ActionNode::EmptyMatchCheck(body_start_reg, reg_ctr, min, loop_return); } RegExpNode* body_node = body->ToNode(compiler, loop_return); if (body_can_be_empty) { // If the body can be empty we need to store the start position // so we can bail out if it was empty. body_node = ActionNode::StorePosition(body_start_reg, false, body_node); } if (needs_capture_clearing) { // Before entering the body of this loop we need to clear captures. body_node = ActionNode::ClearCaptures(capture_registers, body_node); } GuardedAlternative body_alt(body_node); if (has_max) { Guard* body_guard = new (zone) Guard(reg_ctr, Guard::LT, max); body_alt.AddGuard(body_guard, zone); } GuardedAlternative rest_alt(on_success); if (has_min) { Guard* rest_guard = new (zone) Guard(reg_ctr, Guard::GEQ, min); rest_alt.AddGuard(rest_guard, zone); } if (is_greedy) { center->AddLoopAlternative(body_alt); center->AddContinueAlternative(rest_alt); } else { center->AddContinueAlternative(rest_alt); center->AddLoopAlternative(body_alt); } if (needs_counter) { return ActionNode::SetRegister(reg_ctr, 0, center); } else { return center; } } namespace { // Desugar \b to (?<=\w)(?=\W)|(?<=\W)(?=\w) and // \B to (?<=\w)(?=\w)|(?<=\W)(?=\W) RegExpNode* BoundaryAssertionAsLookaround(RegExpCompiler* compiler, RegExpNode* on_success, RegExpAssertion::AssertionType type, RegExpFlags flags) { ASSERT(flags.NeedsUnicodeCaseEquivalents()); ZoneGrowableArray* word_range = new ZoneGrowableArray(2); CharacterRange::AddClassEscape('w', word_range, true); int stack_register = compiler->UnicodeLookaroundStackRegister(); int position_register = compiler->UnicodeLookaroundPositionRegister(); ChoiceNode* result = new (OZ) ChoiceNode(2, OZ); // Add two choices. The (non-)boundary could start with a word or // a non-word-character. for (int i = 0; i < 2; i++) { bool lookbehind_for_word = i == 0; bool lookahead_for_word = (type == RegExpAssertion::BOUNDARY) ^ lookbehind_for_word; // Look to the left. RegExpLookaround::Builder lookbehind(lookbehind_for_word, on_success, stack_register, position_register); RegExpNode* backward = TextNode::CreateForCharacterRanges( word_range, true, lookbehind.on_match_success(), flags); // Look to the right. RegExpLookaround::Builder lookahead(lookahead_for_word, lookbehind.ForMatch(backward), stack_register, position_register); RegExpNode* forward = TextNode::CreateForCharacterRanges( word_range, false, lookahead.on_match_success(), flags); result->AddAlternative(GuardedAlternative(lookahead.ForMatch(forward))); } return result; } } // anonymous namespace RegExpNode* RegExpAssertion::ToNode(RegExpCompiler* compiler, RegExpNode* on_success) { switch (assertion_type()) { case START_OF_LINE: return AssertionNode::AfterNewline(on_success); case START_OF_INPUT: return AssertionNode::AtStart(on_success); case BOUNDARY: return flags_.NeedsUnicodeCaseEquivalents() ? BoundaryAssertionAsLookaround(compiler, on_success, BOUNDARY, flags_) : AssertionNode::AtBoundary(on_success); case NON_BOUNDARY: return flags_.NeedsUnicodeCaseEquivalents() ? BoundaryAssertionAsLookaround(compiler, on_success, NON_BOUNDARY, flags_) : AssertionNode::AtNonBoundary(on_success); case END_OF_INPUT: return AssertionNode::AtEnd(on_success); case END_OF_LINE: { // Compile $ in multiline regexps as an alternation with a positive // lookahead in one side and an end-of-input on the other side. // We need two registers for the lookahead. intptr_t stack_pointer_register = compiler->AllocateRegister(); intptr_t position_register = compiler->AllocateRegister(); // The ChoiceNode to distinguish between a newline and end-of-input. ChoiceNode* result = new ChoiceNode(2, on_success->zone()); // Create a newline atom. ZoneGrowableArray* newline_ranges = new ZoneGrowableArray(3); CharacterRange::AddClassEscape('n', newline_ranges); RegExpCharacterClass* newline_atom = new RegExpCharacterClass('n', RegExpFlags()); TextNode* newline_matcher = new TextNode(newline_atom, /*read_backwards=*/false, ActionNode::PositiveSubmatchSuccess( stack_pointer_register, position_register, 0, // No captures inside. -1, // Ignored if no captures. on_success)); // Create an end-of-input matcher. RegExpNode* end_of_line = ActionNode::BeginSubmatch( stack_pointer_register, position_register, newline_matcher); // Add the two alternatives to the ChoiceNode. GuardedAlternative eol_alternative(end_of_line); result->AddAlternative(eol_alternative); GuardedAlternative end_alternative(AssertionNode::AtEnd(on_success)); result->AddAlternative(end_alternative); return result; } default: UNREACHABLE(); } return on_success; } RegExpNode* RegExpBackReference::ToNode(RegExpCompiler* compiler, RegExpNode* on_success) { return new (OZ) BackReferenceNode(RegExpCapture::StartRegister(index()), RegExpCapture::EndRegister(index()), flags_, compiler->read_backward(), on_success); } RegExpNode* RegExpEmpty::ToNode(RegExpCompiler* compiler, RegExpNode* on_success) { return on_success; } RegExpLookaround::Builder::Builder(bool is_positive, RegExpNode* on_success, intptr_t stack_pointer_register, intptr_t position_register, intptr_t capture_register_count, intptr_t capture_register_start) : is_positive_(is_positive), on_success_(on_success), stack_pointer_register_(stack_pointer_register), position_register_(position_register) { if (is_positive_) { on_match_success_ = ActionNode::PositiveSubmatchSuccess( stack_pointer_register, position_register, capture_register_count, capture_register_start, on_success); } else { on_match_success_ = new (OZ) NegativeSubmatchSuccess( stack_pointer_register, position_register, capture_register_count, capture_register_start, OZ); } } RegExpNode* RegExpLookaround::Builder::ForMatch(RegExpNode* match) { if (is_positive_) { return ActionNode::BeginSubmatch(stack_pointer_register_, position_register_, match); } else { Zone* zone = on_success_->zone(); // We use a ChoiceNode to represent the negative lookaround. The first // alternative is the negative match. On success, the end node backtracks. // On failure, the second alternative is tried and leads to success. // NegativeLookaroundChoiceNode is a special ChoiceNode that ignores the // first exit when calculating quick checks. ChoiceNode* choice_node = new (zone) NegativeLookaroundChoiceNode( GuardedAlternative(match), GuardedAlternative(on_success_), zone); return ActionNode::BeginSubmatch(stack_pointer_register_, position_register_, choice_node); } } RegExpNode* RegExpLookaround::ToNode(RegExpCompiler* compiler, RegExpNode* on_success) { intptr_t stack_pointer_register = compiler->AllocateRegister(); intptr_t position_register = compiler->AllocateRegister(); const intptr_t registers_per_capture = 2; const intptr_t register_of_first_capture = 2; intptr_t register_count = capture_count_ * registers_per_capture; intptr_t register_start = register_of_first_capture + capture_from_ * registers_per_capture; RegExpNode* result; bool was_reading_backward = compiler->read_backward(); compiler->set_read_backward(type() == LOOKBEHIND); Builder builder(is_positive(), on_success, stack_pointer_register, position_register, register_count, register_start); RegExpNode* match = body_->ToNode(compiler, builder.on_match_success()); result = builder.ForMatch(match); compiler->set_read_backward(was_reading_backward); return result; } RegExpNode* RegExpCapture::ToNode(RegExpCompiler* compiler, RegExpNode* on_success) { return ToNode(body(), index(), compiler, on_success); } RegExpNode* RegExpCapture::ToNode(RegExpTree* body, intptr_t index, RegExpCompiler* compiler, RegExpNode* on_success) { ASSERT(body != nullptr); intptr_t start_reg = RegExpCapture::StartRegister(index); intptr_t end_reg = RegExpCapture::EndRegister(index); if (compiler->read_backward()) { intptr_t tmp = end_reg; end_reg = start_reg; start_reg = tmp; } RegExpNode* store_end = ActionNode::StorePosition(end_reg, true, on_success); RegExpNode* body_node = body->ToNode(compiler, store_end); return ActionNode::StorePosition(start_reg, true, body_node); } RegExpNode* RegExpAlternative::ToNode(RegExpCompiler* compiler, RegExpNode* on_success) { ZoneGrowableArray* children = nodes(); RegExpNode* current = on_success; if (compiler->read_backward()) { for (intptr_t i = 0; i < children->length(); i++) { current = children->At(i)->ToNode(compiler, current); } } else { for (intptr_t i = children->length() - 1; i >= 0; i--) { current = children->At(i)->ToNode(compiler, current); } } return current; } static void AddClass(const int32_t* elmv, intptr_t elmc, ZoneGrowableArray* ranges) { elmc--; ASSERT(elmv[elmc] == kRangeEndMarker); for (intptr_t i = 0; i < elmc; i += 2) { ASSERT(elmv[i] < elmv[i + 1]); ranges->Add(CharacterRange(elmv[i], elmv[i + 1] - 1)); } } static void AddClassNegated(const int32_t* elmv, intptr_t elmc, ZoneGrowableArray* ranges) { elmc--; ASSERT(elmv[elmc] == kRangeEndMarker); ASSERT(elmv[0] != 0x0000); ASSERT(elmv[elmc - 1] != Utf::kMaxCodePoint); uint16_t last = 0x0000; for (intptr_t i = 0; i < elmc; i += 2) { ASSERT(last <= elmv[i] - 1); ASSERT(elmv[i] < elmv[i + 1]); ranges->Add(CharacterRange(last, elmv[i] - 1)); last = elmv[i + 1]; } ranges->Add(CharacterRange(last, Utf::kMaxCodePoint)); } void CharacterRange::AddClassEscape(uint16_t type, ZoneGrowableArray* ranges, bool add_unicode_case_equivalents) { if (add_unicode_case_equivalents && (type == 'w' || type == 'W')) { // See #sec-runtime-semantics-wordcharacters-abstract-operation // In case of unicode and ignore_case, we need to create the closure over // case equivalent characters before negating. ZoneGrowableArray* new_ranges = new ZoneGrowableArray(2); AddClass(kWordRanges, kWordRangeCount, new_ranges); AddUnicodeCaseEquivalents(new_ranges); if (type == 'W') { ZoneGrowableArray* negated = new ZoneGrowableArray(2); CharacterRange::Negate(new_ranges, negated); new_ranges = negated; } ranges->AddArray(*new_ranges); return; } AddClassEscape(type, ranges); } void CharacterRange::AddClassEscape(uint16_t type, ZoneGrowableArray* ranges) { switch (type) { case 's': AddClass(kSpaceRanges, kSpaceRangeCount, ranges); break; case 'S': AddClassNegated(kSpaceRanges, kSpaceRangeCount, ranges); break; case 'w': AddClass(kWordRanges, kWordRangeCount, ranges); break; case 'W': AddClassNegated(kWordRanges, kWordRangeCount, ranges); break; case 'd': AddClass(kDigitRanges, kDigitRangeCount, ranges); break; case 'D': AddClassNegated(kDigitRanges, kDigitRangeCount, ranges); break; case '.': AddClassNegated(kLineTerminatorRanges, kLineTerminatorRangeCount, ranges); break; // This is not a character range as defined by the spec but a // convenient shorthand for a character class that matches any // character. case '*': ranges->Add(CharacterRange::Everything()); break; // This is the set of characters matched by the $ and ^ symbols // in multiline mode. case 'n': AddClass(kLineTerminatorRanges, kLineTerminatorRangeCount, ranges); break; default: UNREACHABLE(); } } void CharacterRange::AddCaseEquivalents( ZoneGrowableArray* ranges, bool is_one_byte, Zone* zone) { CharacterRange::Canonicalize(ranges); int range_count = ranges->length(); for (intptr_t i = 0; i < range_count; i++) { CharacterRange range = ranges->At(i); int32_t bottom = range.from(); if (bottom > Utf16::kMaxCodeUnit) continue; int32_t top = Utils::Minimum(range.to(), Utf16::kMaxCodeUnit); // Nothing to be done for surrogates if (bottom >= Utf16::kLeadSurrogateStart && top <= Utf16::kTrailSurrogateEnd) { continue; } if (is_one_byte && !RangeContainsLatin1Equivalents(range)) { if (bottom > Symbols::kMaxOneCharCodeSymbol) continue; if (top > Symbols::kMaxOneCharCodeSymbol) { top = Symbols::kMaxOneCharCodeSymbol; } } unibrow::Mapping jsregexp_uncanonicalize; unibrow::Mapping jsregexp_canonrange; int32_t chars[unibrow::Ecma262UnCanonicalize::kMaxWidth]; if (top == bottom) { // If this is a singleton we just expand the one character. intptr_t length = jsregexp_uncanonicalize.get(bottom, '\0', chars); for (intptr_t i = 0; i < length; i++) { int32_t chr = chars[i]; if (chr != bottom) { ranges->Add(CharacterRange::Singleton(chars[i])); } } } else { // If this is a range we expand the characters block by block, // expanding contiguous subranges (blocks) one at a time. // The approach is as follows. For a given start character we // look up the remainder of the block that contains it (represented // by the end point), for instance we find 'z' if the character // is 'c'. A block is characterized by the property // that all characters uncanonicalize in the same way, except that // each entry in the result is incremented by the distance from the first // element. So a-z is a block because 'a' uncanonicalizes to ['a', 'A'] // and the k'th letter uncanonicalizes to ['a' + k, 'A' + k]. // Once we've found the end point we look up its uncanonicalization // and produce a range for each element. For instance for [c-f] // we look up ['z', 'Z'] and produce [c-f] and [C-F]. We then only // add a range if it is not already contained in the input, so [c-f] // will be skipped but [C-F] will be added. If this range is not // completely contained in a block we do this for all the blocks // covered by the range (handling characters that is not in a block // as a "singleton block"). int32_t range[unibrow::Ecma262UnCanonicalize::kMaxWidth]; intptr_t pos = bottom; while (pos <= top) { intptr_t length = jsregexp_canonrange.get(pos, '\0', range); int32_t block_end; if (length == 0) { block_end = pos; } else { ASSERT(length == 1); block_end = range[0]; } intptr_t end = (block_end > top) ? top : block_end; length = jsregexp_uncanonicalize.get(block_end, '\0', range); for (intptr_t i = 0; i < length; i++) { int32_t c = range[i]; int32_t range_from = c - (block_end - pos); int32_t range_to = c - (block_end - end); if (!(bottom <= range_from && range_to <= top)) { ranges->Add(CharacterRange(range_from, range_to)); } } pos = end + 1; } } } } bool CharacterRange::IsCanonical(ZoneGrowableArray* ranges) { ASSERT(ranges != NULL); intptr_t n = ranges->length(); if (n <= 1) return true; intptr_t max = ranges->At(0).to(); for (intptr_t i = 1; i < n; i++) { CharacterRange next_range = ranges->At(i); if (next_range.from() <= max + 1) return false; max = next_range.to(); } return true; } ZoneGrowableArray* CharacterSet::ranges() { if (ranges_ == NULL) { ranges_ = new ZoneGrowableArray(2); CharacterRange::AddClassEscape(standard_set_type_, ranges_); } return ranges_; } // Move a number of elements in a zone array to another position // in the same array. Handles overlapping source and target areas. static void MoveRanges(ZoneGrowableArray* list, intptr_t from, intptr_t to, intptr_t count) { // Ranges are potentially overlapping. if (from < to) { for (intptr_t i = count - 1; i >= 0; i--) { (*list)[to + i] = list->At(from + i); } } else { for (intptr_t i = 0; i < count; i++) { (*list)[to + i] = list->At(from + i); } } } static intptr_t InsertRangeInCanonicalList( ZoneGrowableArray* list, intptr_t count, CharacterRange insert) { // Inserts a range into list[0..count[, which must be sorted // by from value and non-overlapping and non-adjacent, using at most // list[0..count] for the result. Returns the number of resulting // canonicalized ranges. Inserting a range may collapse existing ranges into // fewer ranges, so the return value can be anything in the range 1..count+1. int32_t from = insert.from(); int32_t to = insert.to(); intptr_t start_pos = 0; intptr_t end_pos = count; for (intptr_t i = count - 1; i >= 0; i--) { CharacterRange current = list->At(i); if (current.from() > to + 1) { end_pos = i; } else if (current.to() + 1 < from) { start_pos = i + 1; break; } } // Inserted range overlaps, or is adjacent to, ranges at positions // [start_pos..end_pos[. Ranges before start_pos or at or after end_pos are // not affected by the insertion. // If start_pos == end_pos, the range must be inserted before start_pos. // if start_pos < end_pos, the entire range from start_pos to end_pos // must be merged with the insert range. if (start_pos == end_pos) { // Insert between existing ranges at position start_pos. if (start_pos < count) { MoveRanges(list, start_pos, start_pos + 1, count - start_pos); } (*list)[start_pos] = insert; return count + 1; } if (start_pos + 1 == end_pos) { // Replace single existing range at position start_pos. CharacterRange to_replace = list->At(start_pos); intptr_t new_from = Utils::Minimum(to_replace.from(), from); intptr_t new_to = Utils::Maximum(to_replace.to(), to); (*list)[start_pos] = CharacterRange(new_from, new_to); return count; } // Replace a number of existing ranges from start_pos to end_pos - 1. // Move the remaining ranges down. intptr_t new_from = Utils::Minimum(list->At(start_pos).from(), from); intptr_t new_to = Utils::Maximum(list->At(end_pos - 1).to(), to); if (end_pos < count) { MoveRanges(list, end_pos, start_pos + 1, count - end_pos); } (*list)[start_pos] = CharacterRange(new_from, new_to); return count - (end_pos - start_pos) + 1; } void CharacterSet::Canonicalize() { // Special/default classes are always considered canonical. The result // of calling ranges() will be sorted. if (ranges_ == NULL) return; CharacterRange::Canonicalize(ranges_); } void CharacterRange::Canonicalize( ZoneGrowableArray* character_ranges) { if (character_ranges->length() <= 1) return; // Check whether ranges are already canonical (increasing, non-overlapping, // non-adjacent). intptr_t n = character_ranges->length(); intptr_t max = character_ranges->At(0).to(); intptr_t i = 1; while (i < n) { CharacterRange current = character_ranges->At(i); if (current.from() <= max + 1) { break; } max = current.to(); i++; } // Canonical until the i'th range. If that's all of them, we are done. if (i == n) return; // The ranges at index i and forward are not canonicalized. Make them so by // doing the equivalent of insertion sort (inserting each into the previous // list, in order). // Notice that inserting a range can reduce the number of ranges in the // result due to combining of adjacent and overlapping ranges. intptr_t read = i; // Range to insert. intptr_t num_canonical = i; // Length of canonicalized part of list. do { num_canonical = InsertRangeInCanonicalList(character_ranges, num_canonical, character_ranges->At(read)); read++; } while (read < n); character_ranges->TruncateTo(num_canonical); ASSERT(CharacterRange::IsCanonical(character_ranges)); } void CharacterRange::Negate(ZoneGrowableArray* ranges, ZoneGrowableArray* negated_ranges) { ASSERT(CharacterRange::IsCanonical(ranges)); ASSERT(negated_ranges->length() == 0); intptr_t range_count = ranges->length(); uint32_t from = 0; intptr_t i = 0; if (range_count > 0 && ranges->At(0).from() == 0) { from = ranges->At(0).to(); i = 1; } while (i < range_count) { CharacterRange range = ranges->At(i); negated_ranges->Add(CharacterRange(from + 1, range.from() - 1)); from = range.to(); i++; } if (from < Utf::kMaxCodePoint) { negated_ranges->Add(CharacterRange(from + 1, Utf::kMaxCodePoint)); } } // ------------------------------------------------------------------- // Splay tree // Workaround for the fact that ZoneGrowableArray does not have contains(). static bool ArrayContains(ZoneGrowableArray* array, unsigned value) { for (intptr_t i = 0; i < array->length(); i++) { if (array->At(i) == value) { return true; } } return false; } OutSet* OutSet::Extend(unsigned value, Zone* zone) { if (Get(value)) return this; if (successors() != nullptr) { for (int i = 0; i < successors()->length(); i++) { OutSet* successor = successors()->At(i); if (successor->Get(value)) return successor; } } else { successors_ = new (zone) ZoneGrowableArray(2); } OutSet* result = new (zone) OutSet(first_, remaining_); result->Set(value, zone); successors()->Add(result); return result; } void OutSet::Set(unsigned value, Zone* zone) { if (value < kFirstLimit) { first_ |= (1 << value); } else { if (remaining_ == NULL) remaining_ = new (zone) ZoneGrowableArray(1); bool remaining_contains_value = ArrayContains(remaining_, value); if (remaining_->is_empty() || !remaining_contains_value) { remaining_->Add(value); } } } bool OutSet::Get(unsigned value) const { if (value < kFirstLimit) { return (first_ & (1 << value)) != 0; } else if (remaining_ == NULL) { return false; } else { return ArrayContains(remaining_, value); } } const int32_t DispatchTable::Config::kNoKey = Utf::kInvalidChar; void DispatchTable::AddRange(CharacterRange full_range, int32_t value, Zone* zone) { CharacterRange current = full_range; if (tree()->is_empty()) { // If this is the first range we just insert into the table. ZoneSplayTree::Locator loc; bool inserted = tree()->Insert(current.from(), &loc); ASSERT(inserted); USE(inserted); loc.set_value( Entry(current.from(), current.to(), empty()->Extend(value, zone))); return; } // First see if there is a range to the left of this one that // overlaps. ZoneSplayTree::Locator loc; if (tree()->FindGreatestLessThan(current.from(), &loc)) { Entry* entry = &loc.value(); // If we've found a range that overlaps with this one, and it // starts strictly to the left of this one, we have to fix it // because the following code only handles ranges that start on // or after the start point of the range we're adding. if (entry->from() < current.from() && entry->to() >= current.from()) { // Snap the overlapping range in half around the start point of // the range we're adding. CharacterRange left = CharacterRange::Range(entry->from(), current.from() - 1); CharacterRange right = CharacterRange::Range(current.from(), entry->to()); // The left part of the overlapping range doesn't overlap. // Truncate the whole entry to be just the left part. entry->set_to(left.to()); // The right part is the one that overlaps. We add this part // to the map and let the next step deal with merging it with // the range we're adding. ZoneSplayTree::Locator loc; bool inserted = tree()->Insert(right.from(), &loc); ASSERT(inserted); USE(inserted); loc.set_value(Entry(right.from(), right.to(), entry->out_set())); } } while (current.is_valid()) { if (tree()->FindLeastGreaterThan(current.from(), &loc) && (loc.value().from() <= current.to()) && (loc.value().to() >= current.from())) { Entry* entry = &loc.value(); // We have overlap. If there is space between the start point of // the range we're adding and where the overlapping range starts // then we have to add a range covering just that space. if (current.from() < entry->from()) { ZoneSplayTree::Locator ins; bool inserted = tree()->Insert(current.from(), &ins); ASSERT(inserted); USE(inserted); ins.set_value(Entry(current.from(), entry->from() - 1, empty()->Extend(value, zone))); current.set_from(entry->from()); } ASSERT(current.from() == entry->from()); // If the overlapping range extends beyond the one we want to add // we have to snap the right part off and add it separately. if (entry->to() > current.to()) { ZoneSplayTree::Locator ins; bool inserted = tree()->Insert(current.to() + 1, &ins); ASSERT(inserted); USE(inserted); ins.set_value(Entry(current.to() + 1, entry->to(), entry->out_set())); entry->set_to(current.to()); } ASSERT(entry->to() <= current.to()); // The overlapping range is now completely contained by the range // we're adding so we can just update it and move the start point // of the range we're adding just past it. entry->AddValue(value, zone); ASSERT(entry->to() + 1 > current.from()); current.set_from(entry->to() + 1); } else { // There is no overlap so we can just add the range ZoneSplayTree::Locator ins; bool inserted = tree()->Insert(current.from(), &ins); ASSERT(inserted); USE(inserted); ins.set_value( Entry(current.from(), current.to(), empty()->Extend(value, zone))); break; } } } OutSet* DispatchTable::Get(int32_t value) { ZoneSplayTree::Locator loc; if (!tree()->FindGreatestLessThan(value, &loc)) return empty(); Entry* entry = &loc.value(); if (value <= entry->to()) return entry->out_set(); else return empty(); } // ------------------------------------------------------------------- // Analysis void Analysis::EnsureAnalyzed(RegExpNode* that) { if (that->info()->been_analyzed || that->info()->being_analyzed) return; that->info()->being_analyzed = true; that->Accept(this); that->info()->being_analyzed = false; that->info()->been_analyzed = true; } void Analysis::VisitEnd(EndNode* that) { // nothing to do } void TextNode::CalculateOffsets() { intptr_t element_count = elements()->length(); // Set up the offsets of the elements relative to the start. This is a fixed // quantity since a TextNode can only contain fixed-width things. intptr_t cp_offset = 0; for (intptr_t i = 0; i < element_count; i++) { TextElement& elm = (*elements())[i]; elm.set_cp_offset(cp_offset); cp_offset += elm.length(); } } void Analysis::VisitText(TextNode* that) { that->MakeCaseIndependent(is_one_byte_); EnsureAnalyzed(that->on_success()); if (!has_failed()) { that->CalculateOffsets(); } } void Analysis::VisitAction(ActionNode* that) { RegExpNode* target = that->on_success(); EnsureAnalyzed(target); if (!has_failed()) { // If the next node is interested in what it follows then this node // has to be interested too so it can pass the information on. that->info()->AddFromFollowing(target->info()); } } void Analysis::VisitChoice(ChoiceNode* that) { NodeInfo* info = that->info(); for (intptr_t i = 0; i < that->alternatives()->length(); i++) { RegExpNode* node = (*that->alternatives())[i].node(); EnsureAnalyzed(node); if (has_failed()) return; // Anything the following nodes need to know has to be known by // this node also, so it can pass it on. info->AddFromFollowing(node->info()); } } void Analysis::VisitLoopChoice(LoopChoiceNode* that) { NodeInfo* info = that->info(); for (intptr_t i = 0; i < that->alternatives()->length(); i++) { RegExpNode* node = (*that->alternatives())[i].node(); if (node != that->loop_node()) { EnsureAnalyzed(node); if (has_failed()) return; info->AddFromFollowing(node->info()); } } // Check the loop last since it may need the value of this node // to get a correct result. EnsureAnalyzed(that->loop_node()); if (!has_failed()) { info->AddFromFollowing(that->loop_node()->info()); } } void Analysis::VisitBackReference(BackReferenceNode* that) { EnsureAnalyzed(that->on_success()); } void Analysis::VisitAssertion(AssertionNode* that) { EnsureAnalyzed(that->on_success()); } void BackReferenceNode::FillInBMInfo(intptr_t offset, intptr_t budget, BoyerMooreLookahead* bm, bool not_at_start) { // Working out the set of characters that a backreference can match is too // hard, so we just say that any character can match. bm->SetRest(offset); SaveBMInfo(bm, not_at_start, offset); } COMPILE_ASSERT(BoyerMoorePositionInfo::kMapSize == RegExpMacroAssembler::kTableSize); void ChoiceNode::FillInBMInfo(intptr_t offset, intptr_t budget, BoyerMooreLookahead* bm, bool not_at_start) { ZoneGrowableArray* alts = alternatives(); budget = (budget - 1) / alts->length(); for (intptr_t i = 0; i < alts->length(); i++) { GuardedAlternative& alt = (*alts)[i]; if (alt.guards() != NULL && alt.guards()->length() != 0) { bm->SetRest(offset); // Give up trying to fill in info. SaveBMInfo(bm, not_at_start, offset); return; } alt.node()->FillInBMInfo(offset, budget, bm, not_at_start); } SaveBMInfo(bm, not_at_start, offset); } void TextNode::FillInBMInfo(intptr_t initial_offset, intptr_t budget, BoyerMooreLookahead* bm, bool not_at_start) { if (initial_offset >= bm->length()) return; intptr_t offset = initial_offset; intptr_t max_char = bm->max_char(); for (intptr_t i = 0; i < elements()->length(); i++) { if (offset >= bm->length()) { if (initial_offset == 0) set_bm_info(not_at_start, bm); return; } TextElement text = elements()->At(i); if (text.text_type() == TextElement::ATOM) { RegExpAtom* atom = text.atom(); for (intptr_t j = 0; j < atom->length(); j++, offset++) { if (offset >= bm->length()) { if (initial_offset == 0) set_bm_info(not_at_start, bm); return; } uint16_t character = atom->data()->At(j); if (atom->flags().IgnoreCase()) { int32_t chars[unibrow::Ecma262UnCanonicalize::kMaxWidth]; intptr_t length = GetCaseIndependentLetters( character, bm->max_char() == Symbols::kMaxOneCharCodeSymbol, chars); for (intptr_t j = 0; j < length; j++) { bm->Set(offset, chars[j]); } } else { if (character <= max_char) bm->Set(offset, character); } } } else { ASSERT(text.text_type() == TextElement::CHAR_CLASS); RegExpCharacterClass* char_class = text.char_class(); ZoneGrowableArray* ranges = char_class->ranges(); if (char_class->is_negated()) { bm->SetAll(offset); } else { for (intptr_t k = 0; k < ranges->length(); k++) { const CharacterRange& range = ranges->At(k); if (range.from() > max_char) continue; intptr_t to = Utils::Minimum(max_char, static_cast(range.to())); bm->SetInterval(offset, Interval(range.from(), to)); } } offset++; } } if (offset >= bm->length()) { if (initial_offset == 0) set_bm_info(not_at_start, bm); return; } on_success()->FillInBMInfo(offset, budget - 1, bm, true); // Not at start after a text node. if (initial_offset == 0) set_bm_info(not_at_start, bm); } RegExpNode* OptionallyStepBackToLeadSurrogate(RegExpCompiler* compiler, RegExpNode* on_success, RegExpFlags flags) { // If the regexp matching starts within a surrogate pair, step back // to the lead surrogate and start matching from there. ASSERT(!compiler->read_backward()); Zone* zone = compiler->zone(); auto lead_surrogates = CharacterRange::List( on_success->zone(), CharacterRange::Range(Utf16::kLeadSurrogateStart, Utf16::kLeadSurrogateEnd)); auto trail_surrogates = CharacterRange::List( on_success->zone(), CharacterRange::Range(Utf16::kTrailSurrogateStart, Utf16::kTrailSurrogateEnd)); ChoiceNode* optional_step_back = new (zone) ChoiceNode(2, zone); int stack_register = compiler->UnicodeLookaroundStackRegister(); int position_register = compiler->UnicodeLookaroundPositionRegister(); RegExpNode* step_back = TextNode::CreateForCharacterRanges( lead_surrogates, /*read_backward=*/true, on_success, flags); RegExpLookaround::Builder builder(/*is_positive=*/true, step_back, stack_register, position_register); RegExpNode* match_trail = TextNode::CreateForCharacterRanges( trail_surrogates, /*read_backward=*/false, builder.on_match_success(), flags); optional_step_back->AddAlternative( GuardedAlternative(builder.ForMatch(match_trail))); optional_step_back->AddAlternative(GuardedAlternative(on_success)); return optional_step_back; } #if !defined(DART_PRECOMPILED_RUNTIME) RegExpEngine::CompilationResult RegExpEngine::CompileIR( RegExpCompileData* data, const ParsedFunction* parsed_function, const ZoneGrowableArray& ic_data_array, intptr_t osr_id) { ASSERT(!FLAG_interpret_irregexp); Zone* zone = Thread::Current()->zone(); const Function& function = parsed_function->function(); const intptr_t specialization_cid = function.string_specialization_cid(); const bool is_sticky = function.is_sticky_specialization(); const bool is_one_byte = (specialization_cid == kOneByteStringCid || specialization_cid == kExternalOneByteStringCid); RegExp& regexp = RegExp::Handle(zone, function.regexp()); const String& pattern = String::Handle(zone, regexp.pattern()); ASSERT(!regexp.IsNull()); ASSERT(!pattern.IsNull()); const bool is_global = regexp.flags().IsGlobal(); const bool is_unicode = regexp.flags().IsUnicode(); RegExpCompiler compiler(data->capture_count, is_one_byte); // TODO(zerny): Frequency sampling is currently disabled because of several // issues. We do not want to store subject strings in the regexp object since // they might be long and we should not prevent their garbage collection. // Passing them to this function explicitly does not help, since we must // generate exactly the same IR for both the unoptimizing and optimizing // pipelines (otherwise it gets confused when i.e. deopt id's differ). // An option would be to store sampling results in the regexp object, but // I'm not sure the performance gains are relevant enough. // Wrap the body of the regexp in capture #0. RegExpNode* captured_body = RegExpCapture::ToNode(data->tree, 0, &compiler, compiler.accept()); RegExpNode* node = captured_body; const bool is_end_anchored = data->tree->IsAnchoredAtEnd(); const bool is_start_anchored = data->tree->IsAnchoredAtStart(); intptr_t max_length = data->tree->max_match(); if (!is_start_anchored && !is_sticky) { // Add a .*? at the beginning, outside the body capture, unless // this expression is anchored at the beginning or is sticky. RegExpNode* loop_node = RegExpQuantifier::ToNode( 0, RegExpTree::kInfinity, false, new (zone) RegExpCharacterClass('*', RegExpFlags()), &compiler, captured_body, data->contains_anchor); if (data->contains_anchor) { // Unroll loop once, to take care of the case that might start // at the start of input. ChoiceNode* first_step_node = new (zone) ChoiceNode(2, zone); first_step_node->AddAlternative(GuardedAlternative(captured_body)); first_step_node->AddAlternative(GuardedAlternative(new (zone) TextNode( new (zone) RegExpCharacterClass('*', RegExpFlags()), /*read_backwards=*/false, loop_node))); node = first_step_node; } else { node = loop_node; } } if (is_one_byte) { node = node->FilterOneByte(RegExpCompiler::kMaxRecursion); // Do it again to propagate the new nodes to places where they were not // put because they had not been calculated yet. if (node != NULL) { node = node->FilterOneByte(RegExpCompiler::kMaxRecursion); } } else if (is_unicode && (is_global || is_sticky)) { node = OptionallyStepBackToLeadSurrogate(&compiler, node, regexp.flags()); } if (node == NULL) node = new (zone) EndNode(EndNode::BACKTRACK, zone); data->node = node; Analysis analysis(is_one_byte); analysis.EnsureAnalyzed(node); if (analysis.has_failed()) { const char* error_message = analysis.error_message(); return CompilationResult(error_message); } // Native regexp implementation. IRRegExpMacroAssembler* macro_assembler = new (zone) IRRegExpMacroAssembler(specialization_cid, data->capture_count, parsed_function, ic_data_array, osr_id, zone); // Inserted here, instead of in Assembler, because it depends on information // in the AST that isn't replicated in the Node structure. static const intptr_t kMaxBacksearchLimit = 1024; if (is_end_anchored && !is_start_anchored && !is_sticky && max_length < kMaxBacksearchLimit) { macro_assembler->SetCurrentPositionFromEnd(max_length); } if (is_global) { RegExpMacroAssembler::GlobalMode mode = RegExpMacroAssembler::GLOBAL; if (data->tree->min_match() > 0) { mode = RegExpMacroAssembler::GLOBAL_NO_ZERO_LENGTH_CHECK; } else if (is_unicode) { mode = RegExpMacroAssembler::GLOBAL_UNICODE; } macro_assembler->set_global_mode(mode); } RegExpEngine::CompilationResult result = compiler.Assemble(macro_assembler, node, data->capture_count, pattern); if (FLAG_trace_irregexp) { macro_assembler->PrintBlocks(); } return result; } #endif // !defined(DART_PRECOMPILED_RUNTIME) RegExpEngine::CompilationResult RegExpEngine::CompileBytecode( RegExpCompileData* data, const RegExp& regexp, bool is_one_byte, bool is_sticky, Zone* zone) { ASSERT(FLAG_interpret_irregexp); const String& pattern = String::Handle(zone, regexp.pattern()); ASSERT(!regexp.IsNull()); ASSERT(!pattern.IsNull()); const bool is_global = regexp.flags().IsGlobal(); const bool is_unicode = regexp.flags().IsUnicode(); RegExpCompiler compiler(data->capture_count, is_one_byte); // TODO(zerny): Frequency sampling is currently disabled because of several // issues. We do not want to store subject strings in the regexp object since // they might be long and we should not prevent their garbage collection. // Passing them to this function explicitly does not help, since we must // generate exactly the same IR for both the unoptimizing and optimizing // pipelines (otherwise it gets confused when i.e. deopt id's differ). // An option would be to store sampling results in the regexp object, but // I'm not sure the performance gains are relevant enough. // Wrap the body of the regexp in capture #0. RegExpNode* captured_body = RegExpCapture::ToNode(data->tree, 0, &compiler, compiler.accept()); RegExpNode* node = captured_body; bool is_end_anchored = data->tree->IsAnchoredAtEnd(); bool is_start_anchored = data->tree->IsAnchoredAtStart(); intptr_t max_length = data->tree->max_match(); if (!is_start_anchored && !is_sticky) { // Add a .*? at the beginning, outside the body capture, unless // this expression is anchored at the beginning. RegExpNode* loop_node = RegExpQuantifier::ToNode( 0, RegExpTree::kInfinity, false, new (zone) RegExpCharacterClass('*', RegExpFlags()), &compiler, captured_body, data->contains_anchor); if (data->contains_anchor) { // Unroll loop once, to take care of the case that might start // at the start of input. ChoiceNode* first_step_node = new (zone) ChoiceNode(2, zone); first_step_node->AddAlternative(GuardedAlternative(captured_body)); first_step_node->AddAlternative(GuardedAlternative(new (zone) TextNode( new (zone) RegExpCharacterClass('*', RegExpFlags()), /*read_backwards=*/false, loop_node))); node = first_step_node; } else { node = loop_node; } } if (is_one_byte) { node = node->FilterOneByte(RegExpCompiler::kMaxRecursion); // Do it again to propagate the new nodes to places where they were not // put because they had not been calculated yet. if (node != NULL) { node = node->FilterOneByte(RegExpCompiler::kMaxRecursion); } } else if (is_unicode && (is_global || is_sticky)) { node = OptionallyStepBackToLeadSurrogate(&compiler, node, regexp.flags()); } if (node == NULL) node = new (zone) EndNode(EndNode::BACKTRACK, zone); data->node = node; Analysis analysis(is_one_byte); analysis.EnsureAnalyzed(node); if (analysis.has_failed()) { const char* error_message = analysis.error_message(); return CompilationResult(error_message); } // Bytecode regexp implementation. ZoneGrowableArray buffer(zone, 1024); BytecodeRegExpMacroAssembler* macro_assembler = new (zone) BytecodeRegExpMacroAssembler(&buffer, zone); // Inserted here, instead of in Assembler, because it depends on information // in the AST that isn't replicated in the Node structure. static const intptr_t kMaxBacksearchLimit = 1024; if (is_end_anchored && !is_start_anchored && !is_sticky && max_length < kMaxBacksearchLimit) { macro_assembler->SetCurrentPositionFromEnd(max_length); } if (is_global) { RegExpMacroAssembler::GlobalMode mode = RegExpMacroAssembler::GLOBAL; if (data->tree->min_match() > 0) { mode = RegExpMacroAssembler::GLOBAL_NO_ZERO_LENGTH_CHECK; } else if (is_unicode) { mode = RegExpMacroAssembler::GLOBAL_UNICODE; } macro_assembler->set_global_mode(mode); } RegExpEngine::CompilationResult result = compiler.Assemble(macro_assembler, node, data->capture_count, pattern); if (FLAG_trace_irregexp) { macro_assembler->PrintBlocks(); } return result; } static void CreateSpecializedFunction(Thread* thread, Zone* zone, const RegExp& regexp, intptr_t specialization_cid, bool sticky, const Object& owner) { const intptr_t kParamCount = RegExpMacroAssembler::kParamCount; Function& fn = Function::Handle(zone, Function::New(Symbols::ColonMatcher(), RawFunction::kIrregexpFunction, true, // Static. false, // Not const. false, // Not abstract. false, // Not external. false, // Not native. owner, TokenPosition::kMinSource)); // TODO(zerny): Share these arrays between all irregexp functions. fn.set_num_fixed_parameters(kParamCount); fn.set_parameter_types( Array::Handle(zone, Array::New(kParamCount, Heap::kOld))); fn.set_parameter_names( Array::Handle(zone, Array::New(kParamCount, Heap::kOld))); fn.SetParameterTypeAt(RegExpMacroAssembler::kParamRegExpIndex, Object::dynamic_type()); fn.SetParameterNameAt(RegExpMacroAssembler::kParamRegExpIndex, Symbols::This()); fn.SetParameterTypeAt(RegExpMacroAssembler::kParamStringIndex, Object::dynamic_type()); fn.SetParameterNameAt(RegExpMacroAssembler::kParamStringIndex, Symbols::string_param()); fn.SetParameterTypeAt(RegExpMacroAssembler::kParamStartOffsetIndex, Object::dynamic_type()); fn.SetParameterNameAt(RegExpMacroAssembler::kParamStartOffsetIndex, Symbols::start_index_param()); fn.set_result_type(Type::Handle(zone, Type::ArrayType())); // Cache the result. regexp.set_function(specialization_cid, sticky, fn); fn.SetRegExpData(regexp, specialization_cid, sticky); fn.set_is_debuggable(false); // The function is compiled lazily during the first call. } RawRegExp* RegExpEngine::CreateRegExp(Thread* thread, const String& pattern, RegExpFlags flags) { Zone* zone = thread->zone(); const RegExp& regexp = RegExp::Handle(RegExp::New()); regexp.set_pattern(pattern); regexp.set_flags(flags); // TODO(zerny): We might want to use normal string searching algorithms // for simple patterns. regexp.set_is_complex(); regexp.set_is_global(); // All dart regexps are global. if (!FLAG_interpret_irregexp) { const Library& lib = Library::Handle(zone, Library::CoreLibrary()); const Class& owner = Class::Handle(zone, lib.LookupClass(Symbols::RegExp())); for (intptr_t cid = kOneByteStringCid; cid <= kExternalTwoByteStringCid; cid++) { CreateSpecializedFunction(thread, zone, regexp, cid, /*sticky=*/false, owner); CreateSpecializedFunction(thread, zone, regexp, cid, /*sticky=*/true, owner); } } return regexp.raw(); } } // namespace dart