mirror of
https://github.com/dart-lang/sdk
synced 2024-09-05 08:24:39 +00:00
Revert "Re-land "[vm] Aggressive write-barrier elimination.""
Reason: Causing numerous DartFuzz crashes
This reverts commit 595038d19f
.
Change-Id: I94e79cf1a3ddf9210a2929128cfc825bf47c92ac
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/136260
Reviewed-by: Ben Konyi <bkonyi@google.com>
This commit is contained in:
parent
21e944f1bc
commit
edc8bd7ec6
|
@ -70,8 +70,6 @@ class BitVector : public ZoneAllocated {
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data_[i / kBitsPerWord] &= ~(static_cast<uword>(1) << (i % kBitsPerWord));
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}
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void Set(intptr_t i, bool value) { value ? Add(i) : Remove(i); }
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bool Equals(const BitVector& other) const;
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// Add all elements that are in the bitvector from.
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@ -94,14 +92,6 @@ class BitVector : public ZoneAllocated {
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return (block & (static_cast<uword>(1) << (i % kBitsPerWord))) != 0;
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}
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bool SubsetOf(const BitVector& other) {
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ASSERT(length_ == other.length_);
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for (intptr_t i = 0; i < data_length_; ++i) {
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if ((data_[i] & other.data_[i]) != data_[i]) return false;
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}
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return true;
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}
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void Clear() {
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for (intptr_t i = 0; i < data_length_; i++) {
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data_[i] = 0;
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@ -612,9 +612,7 @@ void FlowGraphCompiler::VisitBlocks() {
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EmitInstructionPrologue(instr);
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ASSERT(pending_deoptimization_env_ == NULL);
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pending_deoptimization_env_ = instr->env();
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DEBUG_ONLY(current_instruction_ = instr);
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instr->EmitNativeCode(this);
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DEBUG_ONLY(current_instruction_ = nullptr);
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pending_deoptimization_env_ = NULL;
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if (IsPeephole(instr)) {
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ASSERT(top_of_stack_ == nullptr);
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@ -705,9 +703,7 @@ void FlowGraphCompiler::GenerateDeferredCode() {
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slow_path->instruction()->tag());
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SpecialStatsBegin(stats_tag);
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BeginCodeSourceRange();
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DEBUG_ONLY(current_instruction_ = slow_path->instruction());
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slow_path->GenerateCode(this);
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DEBUG_ONLY(current_instruction_ = nullptr);
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EndCodeSourceRange(slow_path->instruction()->token_pos());
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SpecialStatsEnd(stats_tag);
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}
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@ -1117,15 +1117,6 @@ class FlowGraphCompiler : public ValueObject {
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// is amenable to a peephole optimization.
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bool IsPeephole(Instruction* instr) const;
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#ifdef DEBUG
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bool CanCallDart() const {
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return current_instruction_ == nullptr ||
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current_instruction_->CanCallDart();
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}
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#else
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bool CanCallDart() const { return true; }
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#endif
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// This struct contains either function or code, the other one being NULL.
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class StaticCallsStruct : public ZoneAllocated {
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public:
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@ -1219,10 +1210,6 @@ class FlowGraphCompiler : public ValueObject {
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ZoneGrowableArray<const ICData*>* deopt_id_to_ic_data_;
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Array& edge_counters_array_;
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// Instruction current running EmitNativeCode(). Useful for asserts.
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// Does not include Phis and BlockEntrys.
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DEBUG_ONLY(Instruction* current_instruction_ = nullptr);
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DISALLOW_COPY_AND_ASSIGN(FlowGraphCompiler);
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};
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@ -1001,7 +1001,6 @@ void FlowGraphCompiler::GenerateDartCall(intptr_t deopt_id,
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RawPcDescriptors::Kind kind,
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LocationSummary* locs,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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__ BranchLinkPatchable(stub, entry_kind);
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EmitCallsiteMetadata(token_pos, deopt_id, kind, locs);
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}
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@ -1012,7 +1011,6 @@ void FlowGraphCompiler::GenerateStaticDartCall(intptr_t deopt_id,
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LocationSummary* locs,
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const Function& target,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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if (FLAG_precompiled_mode && FLAG_use_bare_instructions) {
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__ GenerateUnRelocatedPcRelativeCall();
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AddPcRelativeCallTarget(target, entry_kind);
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@ -1092,7 +1090,6 @@ void FlowGraphCompiler::EmitInstanceCallJIT(const Code& stub,
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TokenPosition token_pos,
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LocationSummary* locs,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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ASSERT(entry_kind == Code::EntryKind::kNormal ||
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entry_kind == Code::EntryKind::kUnchecked);
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ASSERT(Array::Handle(zone(), ic_data.arguments_descriptor()).Length() > 0);
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@ -1118,7 +1115,6 @@ void FlowGraphCompiler::EmitMegamorphicInstanceCall(
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LocationSummary* locs,
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intptr_t try_index,
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intptr_t slow_path_argument_count) {
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ASSERT(CanCallDart());
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ASSERT(!arguments_descriptor.IsNull() && (arguments_descriptor.Length() > 0));
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const ArgumentsDescriptor args_desc(arguments_descriptor);
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const MegamorphicCache& cache = MegamorphicCache::ZoneHandle(
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@ -1166,7 +1162,6 @@ void FlowGraphCompiler::EmitInstanceCallAOT(const ICData& ic_data,
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LocationSummary* locs,
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Code::EntryKind entry_kind,
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bool receiver_can_be_smi) {
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ASSERT(CanCallDart());
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ASSERT(entry_kind == Code::EntryKind::kNormal ||
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entry_kind == Code::EntryKind::kUnchecked);
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ASSERT(ic_data.NumArgsTested() == 1);
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@ -972,7 +972,6 @@ void FlowGraphCompiler::GenerateDartCall(intptr_t deopt_id,
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RawPcDescriptors::Kind kind,
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LocationSummary* locs,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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__ BranchLinkPatchable(stub, entry_kind);
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EmitCallsiteMetadata(token_pos, deopt_id, kind, locs);
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}
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@ -983,7 +982,6 @@ void FlowGraphCompiler::GenerateStaticDartCall(intptr_t deopt_id,
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LocationSummary* locs,
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const Function& target,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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if (FLAG_precompiled_mode && FLAG_use_bare_instructions) {
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__ GenerateUnRelocatedPcRelativeCall();
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AddPcRelativeCallTarget(target, entry_kind);
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@ -1053,7 +1051,6 @@ void FlowGraphCompiler::EmitInstanceCallJIT(const Code& stub,
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TokenPosition token_pos,
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LocationSummary* locs,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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ASSERT(entry_kind == Code::EntryKind::kNormal ||
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entry_kind == Code::EntryKind::kUnchecked);
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ASSERT(Array::Handle(zone(), ic_data.arguments_descriptor()).Length() > 0);
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@ -1085,7 +1082,6 @@ void FlowGraphCompiler::EmitMegamorphicInstanceCall(
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LocationSummary* locs,
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intptr_t try_index,
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intptr_t slow_path_argument_count) {
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ASSERT(CanCallDart());
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ASSERT(!arguments_descriptor.IsNull() && (arguments_descriptor.Length() > 0));
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const ArgumentsDescriptor args_desc(arguments_descriptor);
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const MegamorphicCache& cache = MegamorphicCache::ZoneHandle(
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@ -1130,7 +1126,6 @@ void FlowGraphCompiler::EmitInstanceCallAOT(const ICData& ic_data,
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LocationSummary* locs,
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Code::EntryKind entry_kind,
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bool receiver_can_be_smi) {
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ASSERT(CanCallDart());
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ASSERT(ic_data.NumArgsTested() == 1);
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const Code& initial_stub = StubCode::UnlinkedCall();
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const char* switchable_call_mode = "smiable";
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@ -867,7 +867,6 @@ void FlowGraphCompiler::GenerateDartCall(intptr_t deopt_id,
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RawPcDescriptors::Kind kind,
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LocationSummary* locs,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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__ Call(stub, /*moveable_target=*/false, entry_kind);
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EmitCallsiteMetadata(token_pos, deopt_id, kind, locs);
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}
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@ -878,7 +877,6 @@ void FlowGraphCompiler::GenerateStaticDartCall(intptr_t deopt_id,
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LocationSummary* locs,
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const Function& target,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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const auto& stub = StubCode::CallStaticFunction();
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__ Call(stub, /*movable_target=*/true, entry_kind);
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EmitCallsiteMetadata(token_pos, deopt_id, kind, locs);
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@ -950,7 +948,6 @@ void FlowGraphCompiler::EmitInstanceCallJIT(const Code& stub,
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TokenPosition token_pos,
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LocationSummary* locs,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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ASSERT(entry_kind == Code::EntryKind::kNormal ||
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entry_kind == Code::EntryKind::kUnchecked);
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ASSERT(Array::Handle(ic_data.arguments_descriptor()).Length() > 0);
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@ -976,7 +973,6 @@ void FlowGraphCompiler::EmitMegamorphicInstanceCall(
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LocationSummary* locs,
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intptr_t try_index,
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intptr_t slow_path_argument_count) {
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ASSERT(CanCallDart());
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ASSERT(!arguments_descriptor.IsNull() && (arguments_descriptor.Length() > 0));
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const ArgumentsDescriptor args_desc(arguments_descriptor);
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const MegamorphicCache& cache = MegamorphicCache::ZoneHandle(
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@ -986,7 +986,6 @@ void FlowGraphCompiler::GenerateDartCall(intptr_t deopt_id,
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RawPcDescriptors::Kind kind,
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LocationSummary* locs,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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__ CallPatchable(stub, entry_kind);
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EmitCallsiteMetadata(token_pos, deopt_id, kind, locs);
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}
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@ -997,7 +996,6 @@ void FlowGraphCompiler::GenerateStaticDartCall(intptr_t deopt_id,
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LocationSummary* locs,
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const Function& target,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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ASSERT(is_optimizing());
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if (FLAG_precompiled_mode && FLAG_use_bare_instructions) {
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__ GenerateUnRelocatedPcRelativeCall();
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@ -1081,7 +1079,6 @@ void FlowGraphCompiler::EmitInstanceCallJIT(const Code& stub,
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TokenPosition token_pos,
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LocationSummary* locs,
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Code::EntryKind entry_kind) {
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ASSERT(CanCallDart());
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ASSERT(entry_kind == Code::EntryKind::kNormal ||
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entry_kind == Code::EntryKind::kUnchecked);
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ASSERT(Array::Handle(zone(), ic_data.arguments_descriptor()).Length() > 0);
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@ -1107,7 +1104,6 @@ void FlowGraphCompiler::EmitMegamorphicInstanceCall(
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LocationSummary* locs,
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intptr_t try_index,
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intptr_t slow_path_argument_count) {
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ASSERT(CanCallDart());
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ASSERT(!arguments_descriptor.IsNull() && (arguments_descriptor.Length() > 0));
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const ArgumentsDescriptor args_desc(arguments_descriptor);
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const MegamorphicCache& cache = MegamorphicCache::ZoneHandle(
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@ -1149,7 +1145,6 @@ void FlowGraphCompiler::EmitInstanceCallAOT(const ICData& ic_data,
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LocationSummary* locs,
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Code::EntryKind entry_kind,
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bool receiver_can_be_smi) {
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ASSERT(CanCallDart());
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ASSERT(entry_kind == Code::EntryKind::kNormal ||
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entry_kind == Code::EntryKind::kUnchecked);
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ASSERT(ic_data.NumArgsTested() == 1);
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|
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@ -1031,15 +1031,6 @@ class Instruction : public ZoneAllocated {
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// See StoreInstanceFieldInstr::HasUnknownSideEffects() for rationale.
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virtual bool HasUnknownSideEffects() const = 0;
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// Whether this instruction can call Dart code without going through
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// the runtime.
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//
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// Must be true for any instruction which can call Dart code without
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// first creating an exit frame to transition into the runtime.
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//
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// See also WriteBarrierElimination and Thread::RememberLiveTemporaries().
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virtual bool CanCallDart() const { return false; }
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virtual bool CanTriggerGC() const;
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// Get the block entry for this instruction.
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@ -3152,8 +3143,6 @@ class BranchInstr : public Instruction {
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return comparison()->HasUnknownSideEffects();
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}
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virtual bool CanCallDart() const { return comparison()->CanCallDart(); }
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ComparisonInstr* comparison() const { return comparison_; }
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void SetComparison(ComparisonInstr* comp);
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@ -3720,7 +3709,6 @@ class ClosureCallInstr : public TemplateDartCall<1> {
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virtual bool ComputeCanDeoptimize() const { return !FLAG_precompiled_mode; }
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virtual bool HasUnknownSideEffects() const { return true; }
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virtual bool CanCallDart() const { return true; }
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Code::EntryKind entry_kind() const { return entry_kind_; }
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@ -3796,7 +3784,6 @@ class InstanceCallBaseInstr : public TemplateDartCall<0> {
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}
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virtual bool HasUnknownSideEffects() const { return true; }
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virtual bool CanCallDart() const { return true; }
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void SetResultType(Zone* zone, CompileType new_type) {
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result_type_ = new (zone) CompileType(new_type);
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|
@ -4348,7 +4335,6 @@ class IfThenElseInstr : public Definition {
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virtual bool HasUnknownSideEffects() const {
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return comparison()->HasUnknownSideEffects();
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}
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virtual bool CanCallDart() const { return comparison()->CanCallDart(); }
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virtual bool AttributesEqual(Instruction* other) const {
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IfThenElseInstr* other_if_then_else = other->AsIfThenElse();
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@ -4477,7 +4463,6 @@ class StaticCallInstr : public TemplateDartCall<0> {
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}
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virtual bool HasUnknownSideEffects() const { return true; }
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virtual bool CanCallDart() const { return true; }
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// Initialize result type of this call instruction if target is a recognized
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// method or has pragma annotation.
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@ -4736,9 +4721,6 @@ class NativeCallInstr : public TemplateDartCall<0> {
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virtual bool HasUnknownSideEffects() const { return true; }
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// Always creates an exit frame before more Dart code can be called.
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virtual bool CanCallDart() const { return false; }
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void SetupNative();
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PRINT_OPERANDS_TO_SUPPORT
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|
@ -4798,9 +4780,6 @@ class FfiCallInstr : public Definition {
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virtual bool HasUnknownSideEffects() const { return true; }
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// Always creates an exit frame before more Dart code can be called.
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virtual bool CanCallDart() const { return false; }
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virtual Representation RequiredInputRepresentation(intptr_t idx) const;
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virtual Representation representation() const;
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|
@ -5350,7 +5329,6 @@ class StringInterpolateInstr : public TemplateDefinition<1, Throws> {
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virtual CompileType ComputeType() const;
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// Issues a static call to Dart code which calls toString on objects.
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virtual bool HasUnknownSideEffects() const { return true; }
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virtual bool CanCallDart() const { return true; }
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virtual bool ComputeCanDeoptimize() const { return !FLAG_precompiled_mode; }
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const Function& CallFunction() const;
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@ -7028,7 +7006,6 @@ class CheckedSmiOpInstr : public TemplateDefinition<2, Throws> {
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virtual bool RecomputeType();
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virtual bool HasUnknownSideEffects() const { return true; }
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virtual bool CanCallDart() const { return true; }
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|
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virtual Definition* Canonicalize(FlowGraph* flow_graph);
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|
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|
@ -7073,7 +7050,6 @@ class CheckedSmiComparisonInstr : public TemplateComparison<2, Throws> {
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bool is_negated() const { return is_negated_; }
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|
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virtual bool HasUnknownSideEffects() const { return true; }
|
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virtual bool CanCallDart() const { return true; }
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PRINT_OPERANDS_TO_SUPPORT
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|
@ -7709,8 +7685,6 @@ class DoubleToIntegerInstr : public TemplateDefinition<1, Throws> {
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|
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virtual bool HasUnknownSideEffects() const { return false; }
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|
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virtual bool CanCallDart() const { return true; }
|
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|
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private:
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InstanceCallInstr* instance_call_;
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|
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|
|
|
@ -19,7 +19,6 @@
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#include "vm/compiler/backend/redundancy_elimination.h"
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#include "vm/compiler/backend/type_propagator.h"
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#include "vm/compiler/call_specializer.h"
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#include "vm/compiler/write_barrier_elimination.h"
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#if defined(DART_PRECOMPILER)
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#include "vm/compiler/aot/aot_call_specializer.h"
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#include "vm/compiler/aot/precompiler.h"
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|
@ -530,6 +529,36 @@ COMPILER_PASS(ReorderBlocks, {
|
|||
}
|
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});
|
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|
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static void WriteBarrierElimination(FlowGraph* flow_graph) {
|
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for (BlockIterator block_it = flow_graph->reverse_postorder_iterator();
|
||||
!block_it.Done(); block_it.Advance()) {
|
||||
BlockEntryInstr* block = block_it.Current();
|
||||
Definition* last_allocated = nullptr;
|
||||
for (ForwardInstructionIterator it(block); !it.Done(); it.Advance()) {
|
||||
Instruction* current = it.Current();
|
||||
if (!current->CanTriggerGC()) {
|
||||
if (StoreInstanceFieldInstr* instr = current->AsStoreInstanceField()) {
|
||||
if (instr->instance()->definition() == last_allocated) {
|
||||
instr->set_emit_store_barrier(kNoStoreBarrier);
|
||||
}
|
||||
continue;
|
||||
}
|
||||
}
|
||||
|
||||
if (AllocationInstr* alloc = current->AsAllocation()) {
|
||||
if (alloc->WillAllocateNewOrRemembered()) {
|
||||
last_allocated = alloc;
|
||||
continue;
|
||||
}
|
||||
}
|
||||
|
||||
if (current->CanTriggerGC()) {
|
||||
last_allocated = nullptr;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
COMPILER_PASS(WriteBarrierElimination,
|
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{ WriteBarrierElimination(flow_graph); });
|
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|
||||
|
|
|
@ -166,8 +166,6 @@ compiler_sources = [
|
|||
"stub_code_compiler_arm64.cc",
|
||||
"stub_code_compiler_ia32.cc",
|
||||
"stub_code_compiler_x64.cc",
|
||||
"write_barrier_elimination.cc",
|
||||
"write_barrier_elimination.h",
|
||||
]
|
||||
|
||||
compiler_sources_tests = [
|
||||
|
|
|
@ -1,280 +0,0 @@
|
|||
// Copyright (c) 2020, 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 <functional>
|
||||
|
||||
#include "vm/compiler/backend/flow_graph.h"
|
||||
#include "vm/compiler/compiler_pass.h"
|
||||
#include "vm/compiler/write_barrier_elimination.h"
|
||||
|
||||
namespace dart {
|
||||
|
||||
class DefinitionIndexPairTrait {
|
||||
public:
|
||||
typedef Definition* Key;
|
||||
typedef intptr_t Value;
|
||||
typedef struct {
|
||||
Definition* definition;
|
||||
intptr_t index;
|
||||
} Pair;
|
||||
|
||||
static Key KeyOf(Pair kv) { return kv.definition; }
|
||||
static Value ValueOf(Pair kv) { return kv.index; }
|
||||
static inline intptr_t Hashcode(Key key) { return std::hash<Key>()(key); }
|
||||
static inline bool IsKeyEqual(Pair kv, Key key) {
|
||||
return kv.definition == key;
|
||||
}
|
||||
};
|
||||
|
||||
typedef DirectChainedHashMap<DefinitionIndexPairTrait> DefinitionIndexMap;
|
||||
|
||||
// Inter-block write-barrier elimination.
|
||||
//
|
||||
// This optimization removes write barriers from some store instructions under
|
||||
// certain assumptions which the runtime is responsible to sustain.
|
||||
//
|
||||
// We can skip a write barrier on a StoreInstanceField to a container object X
|
||||
// if we know that either:
|
||||
// - X is in new-space, or
|
||||
// - X is in old-space, and:
|
||||
// - X is in the store buffer, and
|
||||
// - X is in the deferred marking stack (if concurrent marking is enabled)
|
||||
//
|
||||
// The result of an Allocation instruction (Instruction::IsAllocation()) will
|
||||
// satisfy one of these requirements immediately after the instruction
|
||||
// if WillAllocateNewOrRemembered() is true.
|
||||
//
|
||||
// Without runtime support, we would have to assume that any instruction which
|
||||
// can trigger a new-space scavenge (Instruction::CanTriggerGC()) might promote
|
||||
// a new-space temporary into old-space, and we could not skip a store barrier
|
||||
// on a write into it afterward.
|
||||
//
|
||||
// However, many instructions can trigger GC in unlikely cases, like
|
||||
// CheckStackOverflow and Box. To avoid interrupting write barrier elimination
|
||||
// across these instructions, the runtime ensures that any live temporaries
|
||||
// (except arrays) promoted during a scavenge caused by a non-Dart-call
|
||||
// instruction (see Instruction::CanCallDart()) will be added to the store
|
||||
// buffer. Additionally, if concurrent marking was initiated, the runtime
|
||||
// ensures that all live temporaries are also in the deferred marking stack.
|
||||
//
|
||||
// See also Thread::RememberLiveTemporaries() and
|
||||
// Thread::DeferredMarkLiveTemporaries().
|
||||
class WriteBarrierElimination : public ValueObject {
|
||||
public:
|
||||
WriteBarrierElimination(Zone* zone, FlowGraph* flow_graph);
|
||||
|
||||
void Analyze();
|
||||
void SaveResults();
|
||||
|
||||
private:
|
||||
void IndexDefinitions(Zone* zone);
|
||||
|
||||
bool AnalyzeBlock(BlockEntryInstr* entry);
|
||||
void MergePredecessors(BlockEntryInstr* entry);
|
||||
|
||||
void UpdateVectorForBlock(BlockEntryInstr* entry, bool finalize);
|
||||
|
||||
static intptr_t Index(BlockEntryInstr* entry) {
|
||||
return entry->postorder_number();
|
||||
}
|
||||
|
||||
intptr_t Index(Definition* def) {
|
||||
ASSERT(IsUsable(def));
|
||||
return definition_indices_.LookupValue(def) - 1;
|
||||
}
|
||||
|
||||
bool IsUsable(Definition* def) {
|
||||
return def->IsPhi() || (def->IsAllocation() &&
|
||||
def->AsAllocation()->WillAllocateNewOrRemembered());
|
||||
}
|
||||
|
||||
FlowGraph* const flow_graph_;
|
||||
const GrowableArray<BlockEntryInstr*>* const block_order_;
|
||||
|
||||
// Number of usable definitions in the graph.
|
||||
intptr_t definition_count_ = 0;
|
||||
|
||||
// Maps each usable definition to its index in the bitvectors.
|
||||
DefinitionIndexMap definition_indices_;
|
||||
|
||||
// Bitvector with all non-Array-allocation instructions set. Used to
|
||||
// un-mark Array allocations as usable.
|
||||
BitVector* array_allocations_mask_;
|
||||
|
||||
// Bitvectors for each block of which allocations are new or remembered
|
||||
// at the start (after Phis).
|
||||
GrowableArray<BitVector*> usable_allocs_in_;
|
||||
|
||||
// Bitvectors for each block of which allocations are new or remembered
|
||||
// at the end of the block.
|
||||
GrowableArray<BitVector*> usable_allocs_out_;
|
||||
|
||||
// Remaining blocks to process.
|
||||
GrowableArray<BlockEntryInstr*> worklist_;
|
||||
|
||||
// Temporary used in many functions to avoid repeated zone allocation.
|
||||
BitVector* vector_;
|
||||
};
|
||||
|
||||
WriteBarrierElimination::WriteBarrierElimination(Zone* zone,
|
||||
FlowGraph* flow_graph)
|
||||
: flow_graph_(flow_graph), block_order_(&flow_graph->postorder()) {
|
||||
IndexDefinitions(zone);
|
||||
|
||||
for (intptr_t i = 0; i < block_order_->length(); ++i) {
|
||||
usable_allocs_in_.Add(new (zone) BitVector(zone, definition_count_));
|
||||
usable_allocs_in_[i]->CopyFrom(vector_);
|
||||
|
||||
usable_allocs_out_.Add(new (zone) BitVector(zone, definition_count_));
|
||||
usable_allocs_out_[i]->CopyFrom(vector_);
|
||||
}
|
||||
}
|
||||
|
||||
void WriteBarrierElimination::Analyze() {
|
||||
for (intptr_t i = 0; i < block_order_->length(); ++i) {
|
||||
worklist_.Add(block_order_->At(i));
|
||||
}
|
||||
|
||||
while (!worklist_.is_empty()) {
|
||||
auto* const entry = worklist_.RemoveLast();
|
||||
if (AnalyzeBlock(entry)) {
|
||||
for (intptr_t i = 0; i < entry->SuccessorCount(); ++i) {
|
||||
worklist_.Add(entry->SuccessorAt(i));
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
void WriteBarrierElimination::SaveResults() {
|
||||
for (intptr_t i = 0; i < block_order_->length(); ++i) {
|
||||
vector_->CopyFrom(usable_allocs_in_[i]);
|
||||
UpdateVectorForBlock(block_order_->At(i), /*finalize=*/true);
|
||||
}
|
||||
}
|
||||
|
||||
void WriteBarrierElimination::IndexDefinitions(Zone* zone) {
|
||||
GrowableArray<bool> array_allocations(10);
|
||||
|
||||
for (intptr_t i = 0; i < block_order_->length(); ++i) {
|
||||
BlockEntryInstr* const block = block_order_->At(i);
|
||||
if (block->IsJoinEntry()) {
|
||||
for (PhiIterator it(block->AsJoinEntry()); !it.Done(); it.Advance()) {
|
||||
definition_indices_.Insert({it.Current(), ++definition_count_});
|
||||
array_allocations.Add(false);
|
||||
}
|
||||
}
|
||||
for (ForwardInstructionIterator it(block); !it.Done(); it.Advance()) {
|
||||
if (Definition* current = it.Current()->AsDefinition()) {
|
||||
if (IsUsable(current)) {
|
||||
definition_indices_.Insert({current, ++definition_count_});
|
||||
array_allocations.Add(current->IsCreateArray());
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
vector_ = new (zone) BitVector(zone, definition_count_);
|
||||
vector_->SetAll();
|
||||
array_allocations_mask_ = new (zone) BitVector(zone, definition_count_);
|
||||
for (intptr_t i = 0; i < definition_count_; ++i) {
|
||||
if (!array_allocations[i]) array_allocations_mask_->Add(i);
|
||||
}
|
||||
}
|
||||
|
||||
void WriteBarrierElimination::MergePredecessors(BlockEntryInstr* entry) {
|
||||
vector_->Clear();
|
||||
for (intptr_t i = 0; i < entry->PredecessorCount(); ++i) {
|
||||
BitVector* predecessor_set =
|
||||
usable_allocs_out_[Index(entry->PredecessorAt(i))];
|
||||
if (i == 0) {
|
||||
vector_->AddAll(predecessor_set);
|
||||
} else {
|
||||
vector_->Intersect(predecessor_set);
|
||||
}
|
||||
}
|
||||
|
||||
if (JoinEntryInstr* join = entry->AsJoinEntry()) {
|
||||
// A Phi is usable if and only if all its inputs are usable.
|
||||
for (PhiIterator it(join); !it.Done(); it.Advance()) {
|
||||
PhiInstr* phi = it.Current();
|
||||
ASSERT(phi->InputCount() == entry->PredecessorCount());
|
||||
bool is_usable = true;
|
||||
for (intptr_t i = 0; i < phi->InputCount(); ++i) {
|
||||
BitVector* const predecessor_set =
|
||||
usable_allocs_out_[Index(entry->PredecessorAt(i))];
|
||||
Definition* const origin = phi->InputAt(i)->definition();
|
||||
if (!IsUsable(origin) || !predecessor_set->Contains(Index(origin))) {
|
||||
is_usable = false;
|
||||
break;
|
||||
}
|
||||
}
|
||||
vector_->Set(Index(phi), is_usable);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
bool WriteBarrierElimination::AnalyzeBlock(BlockEntryInstr* entry) {
|
||||
// Recompute the usable allocs in-set.
|
||||
MergePredecessors(entry);
|
||||
|
||||
// If the in-set has not changed, there's no work to do.
|
||||
BitVector* const in_set = usable_allocs_in_[Index(entry)];
|
||||
ASSERT(vector_->SubsetOf(*in_set)); // convergence
|
||||
if (vector_->Equals(*in_set)) {
|
||||
return false;
|
||||
} else {
|
||||
usable_allocs_in_[Index(entry)]->CopyFrom(vector_);
|
||||
}
|
||||
|
||||
UpdateVectorForBlock(entry, /*finalize=*/false);
|
||||
|
||||
// Successors only need to be updated if the out-set changes.
|
||||
if (vector_->Equals(*usable_allocs_out_[Index(entry)])) {
|
||||
return false;
|
||||
} else {
|
||||
BitVector* const out_set = usable_allocs_out_[Index(entry)];
|
||||
ASSERT(vector_->SubsetOf(*out_set)); // convergence
|
||||
out_set->CopyFrom(vector_);
|
||||
return true;
|
||||
}
|
||||
}
|
||||
|
||||
void WriteBarrierElimination::UpdateVectorForBlock(BlockEntryInstr* entry,
|
||||
bool finalize) {
|
||||
for (ForwardInstructionIterator it(entry); !it.Done(); it.Advance()) {
|
||||
Instruction* const current = it.Current();
|
||||
|
||||
if (finalize) {
|
||||
if (StoreInstanceFieldInstr* instr = current->AsStoreInstanceField()) {
|
||||
Definition* const container = instr->instance()->definition();
|
||||
if (IsUsable(container) && vector_->Contains(Index(container))) {
|
||||
instr->set_emit_store_barrier(kNoStoreBarrier);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if (current->CanCallDart()) {
|
||||
vector_->Clear();
|
||||
} else if (current->CanTriggerGC()) {
|
||||
// Clear array allocations. These are not added to the remembered set
|
||||
// by Thread::RememberLiveTemporaries() after a scavenge.
|
||||
vector_->Intersect(array_allocations_mask_);
|
||||
}
|
||||
|
||||
if (AllocationInstr* const alloc = current->AsAllocation()) {
|
||||
if (alloc->WillAllocateNewOrRemembered()) {
|
||||
vector_->Add(Index(alloc));
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
void WriteBarrierElimination(FlowGraph* flow_graph) {
|
||||
class WriteBarrierElimination elimination(Thread::Current()->zone(),
|
||||
flow_graph);
|
||||
elimination.Analyze();
|
||||
elimination.SaveResults();
|
||||
}
|
||||
|
||||
} // namespace dart
|
|
@ -1,15 +0,0 @@
|
|||
// Copyright (c) 2020, 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.
|
||||
|
||||
#ifndef RUNTIME_VM_COMPILER_WRITE_BARRIER_ELIMINATION_H_
|
||||
#define RUNTIME_VM_COMPILER_WRITE_BARRIER_ELIMINATION_H_
|
||||
|
||||
namespace dart {
|
||||
|
||||
class FlowGraph;
|
||||
void WriteBarrierElimination(FlowGraph* flow_graph);
|
||||
|
||||
} // namespace dart
|
||||
|
||||
#endif // RUNTIME_VM_COMPILER_WRITE_BARRIER_ELIMINATION_H_
|
|
@ -799,8 +799,6 @@ void GCMarker::StartConcurrentMark(PageSpace* page_space) {
|
|||
ASSERT(result);
|
||||
}
|
||||
|
||||
isolate_->DeferredMarkLiveTemporaries();
|
||||
|
||||
// Wait for roots to be marked before exiting safepoint.
|
||||
MonitorLocker ml(&root_slices_monitor_);
|
||||
while (root_slices_finished_ != kNumRootSlices) {
|
||||
|
|
|
@ -1074,9 +1074,6 @@ void Scavenger::Scavenge() {
|
|||
ProcessWeakReferences();
|
||||
page_space->ReleaseDataLock();
|
||||
|
||||
// Restore write-barrier assumptions.
|
||||
isolate->RememberLiveTemporaries();
|
||||
|
||||
// Scavenge finished. Run accounting.
|
||||
int64_t end = OS::GetCurrentMonotonicMicros();
|
||||
heap_->RecordTime(kProcessToSpace, process_to_space - iterate_roots);
|
||||
|
|
|
@ -2397,18 +2397,6 @@ void Isolate::ReleaseStoreBuffers() {
|
|||
thread_registry()->ReleaseStoreBuffers(this);
|
||||
}
|
||||
|
||||
void Isolate::RememberLiveTemporaries() {
|
||||
if (mutator_thread_ != nullptr) {
|
||||
mutator_thread_->RememberLiveTemporaries();
|
||||
}
|
||||
}
|
||||
|
||||
void Isolate::DeferredMarkLiveTemporaries() {
|
||||
if (mutator_thread_ != nullptr) {
|
||||
mutator_thread_->DeferredMarkLiveTemporaries();
|
||||
}
|
||||
}
|
||||
|
||||
void Isolate::EnableIncrementalBarrier(MarkingStack* marking_stack,
|
||||
MarkingStack* deferred_marking_stack) {
|
||||
ASSERT(marking_stack_ == nullptr);
|
||||
|
|
|
@ -1075,9 +1075,6 @@ class Isolate : public BaseIsolate, public IntrusiveDListEntry<Isolate> {
|
|||
|
||||
static void NotifyLowMemory();
|
||||
|
||||
void RememberLiveTemporaries();
|
||||
void DeferredMarkLiveTemporaries();
|
||||
|
||||
private:
|
||||
friend class Dart; // Init, InitOnce, Shutdown.
|
||||
friend class IsolateKillerVisitor; // Kill().
|
||||
|
|
|
@ -697,99 +697,6 @@ void Thread::VisitObjectPointers(ObjectPointerVisitor* visitor,
|
|||
}
|
||||
}
|
||||
|
||||
class HandleLiveTemporariesVisitor : public ObjectPointerVisitor {
|
||||
public:
|
||||
explicit HandleLiveTemporariesVisitor(Isolate* isolate,
|
||||
Thread* thread,
|
||||
Thread::HandleLiveTemporariesOp op)
|
||||
: ObjectPointerVisitor(isolate), thread_(thread), op_(op) {}
|
||||
|
||||
void VisitPointers(RawObject** first, RawObject** last) {
|
||||
for (; first != last + 1; first++) {
|
||||
RawObject* obj = *first;
|
||||
// Stores into new-space objects don't need a write barrier.
|
||||
if (obj->IsSmiOrNewObject()) continue;
|
||||
|
||||
// To avoid adding too much work into the remembered set, skip
|
||||
// arrays. Write barrier elimination we'll do this.
|
||||
if (obj->GetClassId() == kArrayCid) continue;
|
||||
|
||||
// Dart code won't store into VM-internal objects.
|
||||
if (!obj->IsDartInstance()) continue;
|
||||
|
||||
// Dart code won't store into canonical instances.
|
||||
if (obj->IsCanonical()) continue;
|
||||
|
||||
// Already remembered, nothing to do.
|
||||
if (op_ == Thread::HandleLiveTemporariesOp::kAddToRememberedSet &&
|
||||
obj->IsRemembered()) {
|
||||
continue;
|
||||
}
|
||||
|
||||
// Objects in the VM isolate heap are immutable and won't be
|
||||
// stored into. Check this condition last because there's no bit
|
||||
// in the header for it.
|
||||
if (obj->InVMIsolateHeap()) continue;
|
||||
|
||||
switch (op_) {
|
||||
case Thread::HandleLiveTemporariesOp::kAddToRememberedSet:
|
||||
obj->AddToRememberedSet(thread_);
|
||||
break;
|
||||
case Thread::HandleLiveTemporariesOp::kAddToDeferredMarkingStack:
|
||||
// Re-scan obj when finalizing marking.
|
||||
thread_->DeferredMarkingStackAddObject(obj);
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
private:
|
||||
Thread* const thread_;
|
||||
Thread::HandleLiveTemporariesOp op_;
|
||||
};
|
||||
|
||||
// Write barrier elimination assumes that all live temporaries will be
|
||||
// in the remembered set after a scavenge triggered by a non-Dart-call
|
||||
// instruction (see Instruction::CanCallDart()), and additionally they will be
|
||||
// in the deferred marking stack if concurrent marking started. Specifically,
|
||||
// this includes any instruction which will always create an exit frame
|
||||
// below the current frame before any other Dart frames.
|
||||
//
|
||||
// Therefore, to support this assumption, we scan the stack after a scavenge
|
||||
// or when concurrent marking begins and add all live temporaries in
|
||||
// Dart frames preceeding an exit frame to the store buffer or deferred
|
||||
// marking stack.
|
||||
void Thread::HandleLiveTemporaries(HandleLiveTemporariesOp op) {
|
||||
ASSERT(IsMutatorThread());
|
||||
|
||||
const StackFrameIterator::CrossThreadPolicy cross_thread_policy =
|
||||
StackFrameIterator::kAllowCrossThreadIteration;
|
||||
StackFrameIterator frames_iterator(top_exit_frame_info(),
|
||||
ValidationPolicy::kDontValidateFrames,
|
||||
this, cross_thread_policy);
|
||||
HandleLiveTemporariesVisitor visitor(isolate(), this, op);
|
||||
bool scan_next_dart_frame = false;
|
||||
for (StackFrame* frame = frames_iterator.NextFrame(); frame != NULL;
|
||||
frame = frames_iterator.NextFrame()) {
|
||||
if (frame->IsExitFrame()) {
|
||||
scan_next_dart_frame = true;
|
||||
} else if (frame->IsDartFrame()) {
|
||||
if (scan_next_dart_frame) {
|
||||
frame->VisitObjectPointers(&visitor);
|
||||
}
|
||||
scan_next_dart_frame = false;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
void Thread::DeferredMarkLiveTemporaries() {
|
||||
HandleLiveTemporaries(HandleLiveTemporariesOp::kAddToDeferredMarkingStack);
|
||||
}
|
||||
|
||||
void Thread::RememberLiveTemporaries() {
|
||||
HandleLiveTemporaries(HandleLiveTemporariesOp::kAddToRememberedSet);
|
||||
}
|
||||
|
||||
bool Thread::CanLoadFromThread(const Object& object) {
|
||||
// In order to allow us to use assembler helper routines with non-[Code]
|
||||
// objects *before* stubs are initialized, we only loop ver the stubs if the
|
||||
|
|
|
@ -819,8 +819,6 @@ class Thread : public ThreadState {
|
|||
// Visit all object pointers.
|
||||
void VisitObjectPointers(ObjectPointerVisitor* visitor,
|
||||
ValidationPolicy validate_frames);
|
||||
void RememberLiveTemporaries();
|
||||
void DeferredMarkLiveTemporaries();
|
||||
|
||||
bool IsValidHandle(Dart_Handle object) const;
|
||||
bool IsValidLocalHandle(Dart_Handle object) const;
|
||||
|
@ -851,13 +849,6 @@ class Thread : public ThreadState {
|
|||
template <class T>
|
||||
T* AllocateReusableHandle();
|
||||
|
||||
enum class HandleLiveTemporariesOp {
|
||||
kAddToRememberedSet,
|
||||
kAddToDeferredMarkingStack
|
||||
};
|
||||
friend class HandleLiveTemporariesVisitor;
|
||||
void HandleLiveTemporaries(HandleLiveTemporariesOp op);
|
||||
|
||||
// Set the current compiler state and return the previous compiler state.
|
||||
CompilerState* SetCompilerState(CompilerState* state) {
|
||||
CompilerState* previous = compiler_state_;
|
||||
|
|
Loading…
Reference in a new issue