dart-sdk/runtime/vm/kernel.h
Jens Johansen da4343348e [kernel] Change constant references; remove need for map
Previously constants were referenced via there relative binary offset,
i.e. a constant reference saying 42 meant at byte offset 42 relative to
the start of the constant table in the binary. This was done to be able
to (on the VM side) read the needed constants lazily. It meant, though,
that constants had to be stored in a map, mapping from the byte position
to the constant.

This change adds a level of indirection when needing the lazy reading,
but lets the constant references reference the constant number instead
so that a constant reference saying 42 means constant number 42,
i.e. constants can be stored in a list instead of in a map.
This is done on the dart side, but the VM still stores it in a map.

The level of indirection is a tabel next to the constant table where
each entry has constant size (4 bytes) from which one can read the
relative byte offset into the constant table from the constant number,
thus still being able to read needed constants lazily.

This CL also cleans up a leftover where for instance double constants
had their textual representation saved as a string in the string indexer
(and thus the output dill) even though they were never referenced.

File size changes:
* Platform: increses 7,816 bytes.
* Compile of dart2js (including platform): decreases 71,424 bytes.

Speed changes:
* Adding `UserTag`s to the code and looking at observatories cpu profile
  on a `pkg/kernel/test/binary_bench.dart --golem AstFromBinaryLazy`
  run of a compile of dart2js reading the constant table has gone
  from ~10% to ~5%.
* Doing statistics on
  `pkg/kernel/test/binary_bench.dart --raw AstFromBinaryLazy` run of a
  compile of dart2js says -6.28169% +/- 4.97269%.
* Golem runs has nothing above the noise level.
  It does say "AstFromBinaryLazy (Intel Xeon) -4.006% (0.4 noise)" and
  "AstFromBinaryEagerP50 (Intel Core i5) -8.929% (0.6 noise)" though.

TEST=All tests running the VM tests this.

Change-Id: I07ead457527a4477de803ee55ba742f5557413d3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/196925
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
2021-05-04 11:08:31 +00:00

261 lines
8.4 KiB
C++

// Copyright (c) 2016, 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_KERNEL_H_
#define RUNTIME_VM_KERNEL_H_
#include <memory>
#include "platform/assert.h"
#include "vm/allocation.h"
#include "vm/globals.h"
#include "vm/growable_array.h"
#include "vm/object.h"
#include "vm/token_position.h"
namespace dart {
namespace kernel {
class NameIndex {
public:
static const int kInvalidName = -1;
NameIndex() : value_(kInvalidName) {}
explicit NameIndex(int value) : value_(value) {}
operator int() const { return value_; }
private:
int value_;
};
} // namespace kernel
} // namespace dart
#if !defined(DART_PRECOMPILED_RUNTIME)
namespace dart {
class BitVector;
class Field;
class ParsedFunction;
class Zone;
namespace kernel {
class Reader;
struct ProcedureAttributesMetadata;
class TableSelectorMetadata;
class StringIndex {
public:
StringIndex() : value_(-1) {}
explicit StringIndex(int value) : value_(value) {}
operator int() const { return value_; }
private:
int value_;
};
const uint8_t kNativeYieldFlags = 0x2;
enum LogicalOperator { kAnd, kOr };
struct ProgramBinary {
ProgramBinary SubView(intptr_t start, intptr_t end) const {
return {typed_data, kernel_data + start, end - start};
}
const ExternalTypedData* typed_data;
const uint8_t* kernel_data;
intptr_t kernel_data_size;
};
class Program {
public:
// Read a kernel Program from the given Reader. Note the returned Program
// can potentially contain several "sub programs", though the library count
// etc will reference the last "sub program" only.
static std::unique_ptr<Program> ReadFrom(Reader* reader,
const char** error = nullptr);
static std::unique_ptr<Program> ReadFromFile(const char* script_uri,
const char** error = nullptr);
static std::unique_ptr<Program> ReadFromBuffer(const uint8_t* buffer,
intptr_t buffer_length,
const char** error = nullptr);
static std::unique_ptr<Program> ReadFromTypedData(
const ExternalTypedData& typed_data, const char** error = nullptr);
bool is_single_program() { return single_program_; }
uint32_t binary_version() { return binary_version_; }
NameIndex main_method() { return main_method_reference_; }
intptr_t source_table_offset() const { return source_table_offset_; }
intptr_t string_table_offset() const { return string_table_offset_; }
intptr_t name_table_offset() const { return name_table_offset_; }
intptr_t metadata_payloads_offset() const {
return metadata_payloads_offset_;
}
intptr_t metadata_mappings_offset() const {
return metadata_mappings_offset_;
}
intptr_t constant_table_offset() { return constant_table_offset_; }
intptr_t component_index_offset() { return component_index_offset_; }
intptr_t library_count() { return library_count_; }
NNBDCompiledMode compilation_mode() const { return compilation_mode_; }
const ProgramBinary& binary() const { return binary_; }
const ExternalTypedData* typed_data() { return binary().typed_data; }
const uint8_t* kernel_data() { return binary().kernel_data; }
intptr_t kernel_data_size() { return binary().kernel_data_size; }
private:
Program() : binary_() {}
bool single_program_;
uint32_t binary_version_;
NameIndex main_method_reference_; // Procedure.
NNBDCompiledMode compilation_mode_;
intptr_t library_count_;
// The offset from the start of the binary to the start of the source table.
intptr_t source_table_offset_;
// The offset from the start of the binary to the start of the constant table.
intptr_t constant_table_offset_;
// The offset from the start of the binary to the start of the ending-index.
intptr_t component_index_offset_;
// The offset from the start of the binary to the canonical name table.
intptr_t name_table_offset_;
// The offset from the start of the binary to the metadata payloads.
intptr_t metadata_payloads_offset_;
// The offset from the start of the binary to the metadata mappings.
intptr_t metadata_mappings_offset_;
// The offset from the start of the binary to the start of the string table.
intptr_t string_table_offset_;
ProgramBinary binary_;
DISALLOW_COPY_AND_ASSIGN(Program);
};
class KernelLineStartsReader {
public:
KernelLineStartsReader(const dart::TypedData& line_starts_data,
dart::Zone* zone);
~KernelLineStartsReader() { delete helper_; }
int32_t DeltaAt(intptr_t index) const {
return helper_->At(line_starts_data_, index);
}
int32_t MaxPosition() const;
// Returns whether the given offset corresponds to a valid source offset
// If it does, then *line and *column (if column is not nullptr) are set
// to the line and column the token starts at.
DART_WARN_UNUSED_RESULT bool LocationForPosition(
intptr_t position,
intptr_t* line,
intptr_t* col = nullptr) const;
// Returns whether any tokens were found for the given line. When found,
// *first_token_index and *last_token_index are set to the first and
// last token on the line, respectively.
DART_WARN_UNUSED_RESULT bool TokenRangeAtLine(
intptr_t line_number,
dart::TokenPosition* first_token_index,
dart::TokenPosition* last_token_index) const;
private:
class KernelLineStartsHelper {
public:
KernelLineStartsHelper() {}
virtual ~KernelLineStartsHelper() {}
virtual int32_t At(const dart::TypedData& data, intptr_t index) const = 0;
private:
DISALLOW_COPY_AND_ASSIGN(KernelLineStartsHelper);
};
class KernelInt8LineStartsHelper : public KernelLineStartsHelper {
public:
KernelInt8LineStartsHelper() {}
virtual int32_t At(const dart::TypedData& data, intptr_t index) const;
private:
DISALLOW_COPY_AND_ASSIGN(KernelInt8LineStartsHelper);
};
class KernelInt16LineStartsHelper : public KernelLineStartsHelper {
public:
KernelInt16LineStartsHelper() {}
virtual int32_t At(const dart::TypedData& data, intptr_t index) const;
private:
DISALLOW_COPY_AND_ASSIGN(KernelInt16LineStartsHelper);
};
class KernelInt32LineStartsHelper : public KernelLineStartsHelper {
public:
KernelInt32LineStartsHelper() {}
virtual int32_t At(const dart::TypedData& data, intptr_t index) const;
private:
DISALLOW_COPY_AND_ASSIGN(KernelInt32LineStartsHelper);
};
const dart::TypedData& line_starts_data_;
KernelLineStartsHelper* helper_;
DISALLOW_COPY_AND_ASSIGN(KernelLineStartsReader);
};
void CollectTokenPositionsFor(const Script& script);
#if !defined(PRODUCT) && !defined(DART_PRECOMPILED_RUNTIME)
ArrayPtr CollectConstConstructorCoverageFrom(const Script& interesting_script);
#endif // !defined(PRODUCT) && !defined(DART_PRECOMPILED_RUNTIME)
ObjectPtr EvaluateStaticConstFieldInitializer(const Field& field);
ObjectPtr EvaluateMetadata(const Library& library,
intptr_t kernel_offset,
bool is_annotations_offset);
ObjectPtr BuildParameterDescriptor(const Function& function);
// Fills in [is_covariant] and [is_generic_covariant_impl] vectors
// according to covariance attributes of [function] parameters.
//
// [is_covariant] and [is_generic_covariant_impl] should contain bitvectors
// of function.NumParameters() length.
void ReadParameterCovariance(const Function& function,
BitVector* is_covariant,
BitVector* is_generic_covariant_impl);
// Returns true if the given function needs dynamic invocation forwarder:
// that is if any of the arguments require checking on the dynamic
// call-site: if function has no parameters or has only covariant parameters
// as such function already checks all of its parameters.
bool NeedsDynamicInvocationForwarder(const Function& function);
ProcedureAttributesMetadata ProcedureAttributesOf(const Function& function,
Zone* zone);
ProcedureAttributesMetadata ProcedureAttributesOf(const Field& field,
Zone* zone);
TableSelectorMetadata* TableSelectorMetadataForProgram(
const KernelProgramInfo& info,
Zone* zone);
} // namespace kernel
} // namespace dart
#endif // !defined(DART_PRECOMPILED_RUNTIME)
#endif // RUNTIME_VM_KERNEL_H_