src/objects/deoptimization-data.h - v8/v8.git - Git at Google

 // Copyright 2023 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #ifndef V8_OBJECTS_DEOPTIMIZATION_DATA_H_
 #define V8_OBJECTS_DEOPTIMIZATION_DATA_H_

 #include <vector>

 #include "src/objects/bytecode-array.h"
 #include "src/objects/fixed-array.h"

 // Has to be the last include (doesn't have include guards):
 #include "src/objects/object-macros.h"

 namespace v8 {
 namespace internal {

 // This class holds data required during deoptimization. It does not have its
 // own instance type.
 class DeoptimizationLiteralArray : public TrustedWeakFixedArray {
  public:
   // Getters for literals. These include runtime checks that the pointer was not
   // cleared, if the literal was held weakly.
   inline Tagged<Object> get(int index) const;
   inline Tagged<Object> get(PtrComprCageBase cage_base, int index) const;

   // TODO(jgruber): Swap these names around. It's confusing that this
   // WeakFixedArray subclass redefines `get` with different semantics.
   inline Tagged<MaybeObject> get_raw(int index) const;

   // Setter for literals. This will set the object as strong or weak depending
   // on InstructionStream::IsWeakObjectInOptimizedCode.
   inline void set(int index, Tagged<Object> value);

   DECL_CAST(DeoptimizationLiteralArray)

   OBJECT_CONSTRUCTORS(DeoptimizationLiteralArray, TrustedWeakFixedArray);
 };

 // The DeoptimizationFrameTranslation is the on-heap representation of
 // translations created during code generation in a (zone-allocated)
 // DeoptimizationFrameTranslationBuilder. The translation specifies how to
 // transform an optimized frame back into one or more unoptimized frames.
 enum class TranslationOpcode;
 class DeoptimizationFrameTranslation : public TrustedByteArray {
  public:
   DECL_CAST(DeoptimizationFrameTranslation)

   struct FrameCount {
     int total_frame_count;
     int js_frame_count;
   };

   class Iterator;

 #ifdef V8_USE_ZLIB
   // Constants describing compressed DeoptimizationFrameTranslation layout. Only
   // relevant if
   // --turbo-compress-frame-translation is enabled.
   static constexpr int kUncompressedSizeOffset = 0;
   static constexpr int kUncompressedSizeSize = kInt32Size;
   static constexpr int kCompressedDataOffset =
       kUncompressedSizeOffset + kUncompressedSizeSize;
   static constexpr int kDeoptimizationFrameTranslationElementSize = kInt32Size;
 #endif  // V8_USE_ZLIB

   inline uint32_t get_int(int offset) const;
   inline void set_int(int offset, uint32_t value);

 #ifdef ENABLE_DISASSEMBLER
   void PrintFrameTranslation(
       std::ostream& os, int index,
       Tagged<DeoptimizationLiteralArray> literal_array) const;
 #endif

   OBJECT_CONSTRUCTORS(DeoptimizationFrameTranslation, TrustedByteArray);
 };

 class DeoptTranslationIterator {
  public:
   DeoptTranslationIterator(base::Vector<const uint8_t> buffer, int index);

   int32_t NextOperand();

   uint32_t NextOperandUnsigned();

   DeoptimizationFrameTranslation::FrameCount EnterBeginOpcode();

   TranslationOpcode NextOpcode();

   TranslationOpcode SeekNextJSFrame();
   TranslationOpcode SeekNextFrame();

   bool HasNextOpcode() const;

   void SkipOperands(int n) {
     for (int i = 0; i < n; i++) NextOperand();
   }

  private:
   TranslationOpcode NextOpcodeAtPreviousIndex();
   uint32_t NextUnsignedOperandAtPreviousIndex();
   void SkipOpcodeAndItsOperandsAtPreviousIndex();

   std::vector<int32_t> uncompressed_contents_;
   const base::Vector<const uint8_t> buffer_;
   int index_;

   // This decrementing counter indicates how many more times to read operations
   // from the previous translation before continuing to move the index forward.
   int remaining_ops_to_use_from_previous_translation_ = 0;

   // An index into buffer_ for operations starting at a previous BEGIN, which
   // can be used to read operations referred to by MATCH_PREVIOUS_TRANSLATION.
   int previous_index_ = 0;

   // When starting a new MATCH_PREVIOUS_TRANSLATION operation, we'll need to
   // advance the previous_index_ by this many steps.
   int ops_since_previous_index_was_updated_ = 0;
 };

 // Iterator over the deoptimization values. The iterator is not GC-safe.
 class DeoptimizationFrameTranslation::Iterator
     : public DeoptTranslationIterator {
  public:
   Iterator(Tagged<DeoptimizationFrameTranslation> buffer, int index);
   DisallowGarbageCollection no_gc_;
 };

 // DeoptimizationData is a fixed array used to hold the deoptimization data for
 // optimized code.  It also contains information about functions that were
 // inlined.  If N different functions were inlined then the first N elements of
 // the literal array will contain these functions.
 //
 // It can be empty.
 class DeoptimizationData : public ProtectedFixedArray {
  public:
   // Layout description.  Indices in the array.
   static const int kFrameTranslationIndex = 0;
   static const int kInlinedFunctionCountIndex = 1;
   static const int kLiteralArrayIndex = 2;
   static const int kOsrBytecodeOffsetIndex = 3;
   static const int kOsrPcOffsetIndex = 4;
   static const int kOptimizationIdIndex = 5;
   static const int kSharedFunctionInfoWrapperIndex = 6;
   static const int kInliningPositionsIndex = 7;
   static const int kDeoptExitStartIndex = 8;
   static const int kEagerDeoptCountIndex = 9;
   static const int kLazyDeoptCountIndex = 10;
   static const int kFirstDeoptEntryIndex = 11;

   // Offsets of deopt entry elements relative to the start of the entry.
   static const int kBytecodeOffsetRawOffset = 0;
   static const int kTranslationIndexOffset = 1;
   static const int kPcOffset = 2;
 #ifdef DEBUG
   static const int kNodeIdOffset = 3;
   static const int kDeoptEntrySize = 4;
 #else   // DEBUG
   static const int kDeoptEntrySize = 3;
 #endif  // DEBUG

 // Simple element accessors.
 #define DECL_ELEMENT_ACCESSORS(name, type) \
   inline type name() const;                \
   inline void Set##name(type value);

   DECL_ELEMENT_ACCESSORS(FrameTranslation,
                          Tagged<DeoptimizationFrameTranslation>)
   DECL_ELEMENT_ACCESSORS(InlinedFunctionCount, Tagged<Smi>)
   DECL_ELEMENT_ACCESSORS(LiteralArray, Tagged<DeoptimizationLiteralArray>)
   DECL_ELEMENT_ACCESSORS(OsrBytecodeOffset, Tagged<Smi>)
   DECL_ELEMENT_ACCESSORS(OsrPcOffset, Tagged<Smi>)
   DECL_ELEMENT_ACCESSORS(OptimizationId, Tagged<Smi>)
   DECL_ELEMENT_ACCESSORS(SharedFunctionInfoWrapper, Tagged<Object>)
   DECL_ELEMENT_ACCESSORS(InliningPositions,
                          Tagged<TrustedPodArray<InliningPosition>>)
   DECL_ELEMENT_ACCESSORS(DeoptExitStart, Tagged<Smi>)
   DECL_ELEMENT_ACCESSORS(EagerDeoptCount, Tagged<Smi>)
   DECL_ELEMENT_ACCESSORS(LazyDeoptCount, Tagged<Smi>)

 #undef DECL_ELEMENT_ACCESSORS

   inline Tagged<Object> SharedFunctionInfo() const;

 // Accessors for elements of the ith deoptimization entry.
 #define DECL_ENTRY_ACCESSORS(name, type) \
   inline type name(int i) const;         \
   inline void Set##name(int i, type value);

   DECL_ENTRY_ACCESSORS(BytecodeOffsetRaw, Tagged<Smi>)
   DECL_ENTRY_ACCESSORS(TranslationIndex, Tagged<Smi>)
   DECL_ENTRY_ACCESSORS(Pc, Tagged<Smi>)
 #ifdef DEBUG
   DECL_ENTRY_ACCESSORS(NodeId, Tagged<Smi>)
 #endif  // DEBUG

 #undef DECL_ENTRY_ACCESSORS

   // In case the innermost frame is a builtin continuation stub, then this field
   // actually contains the builtin id. See uses of
   // `Builtins::GetBuiltinFromBytecodeOffset`.
   // TODO(olivf): Add some validation that callers do not misinterpret the
   // result.
   inline BytecodeOffset GetBytecodeOffsetOrBuiltinContinuationId(int i) const;

   inline void SetBytecodeOffset(int i, BytecodeOffset value);

   inline int DeoptCount() const;

   static const int kNotInlinedIndex = -1;

   // Returns the inlined function at the given position in LiteralArray, or the
   // outer function if index == kNotInlinedIndex.
   Tagged<class SharedFunctionInfo> GetInlinedFunction(int index);

   // Allocates a DeoptimizationData.
   static Handle<DeoptimizationData> New(Isolate* isolate,
                                         int deopt_entry_count);
   static Handle<DeoptimizationData> New(LocalIsolate* isolate,
                                         int deopt_entry_count);

   // Return an empty DeoptimizationData.
   V8_EXPORT_PRIVATE static Handle<DeoptimizationData> Empty(Isolate* isolate);
   V8_EXPORT_PRIVATE static Handle<DeoptimizationData> Empty(
       LocalIsolate* isolate);

   DECL_CAST(DeoptimizationData)

 #ifdef DEBUG
   void Verify(Handle<BytecodeArray> bytecode) const;
 #endif
 #ifdef ENABLE_DISASSEMBLER
   void PrintDeoptimizationData(std::ostream& os) const;
 #endif

  private:
   static int IndexForEntry(int i) {
     return kFirstDeoptEntryIndex + (i * kDeoptEntrySize);
   }

   static int LengthFor(int entry_count) { return IndexForEntry(entry_count); }

   OBJECT_CONSTRUCTORS(DeoptimizationData, ProtectedFixedArray);
 };

 }  // namespace internal
 }  // namespace v8

 #include "src/objects/object-macros-undef.h"

 #endif  // V8_OBJECTS_DEOPTIMIZATION_DATA_H_
	// Copyright 2023 the V8 project authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#ifndef V8_OBJECTS_DEOPTIMIZATION_DATA_H_
	#define V8_OBJECTS_DEOPTIMIZATION_DATA_H_

	#include <vector>

	#include "src/objects/bytecode-array.h"
	#include "src/objects/fixed-array.h"

	// Has to be the last include (doesn't have include guards):
	#include "src/objects/object-macros.h"

	namespace v8 {
	namespace internal {

	// This class holds data required during deoptimization. It does not have its
	// own instance type.
	class DeoptimizationLiteralArray : public TrustedWeakFixedArray {
	public:
	// Getters for literals. These include runtime checks that the pointer was not
	// cleared, if the literal was held weakly.
	inline Tagged<Object> get(int index) const;
	inline Tagged<Object> get(PtrComprCageBase cage_base, int index) const;

	// TODO(jgruber): Swap these names around. It's confusing that this
	// WeakFixedArray subclass redefines `get` with different semantics.
	inline Tagged<MaybeObject> get_raw(int index) const;

	// Setter for literals. This will set the object as strong or weak depending
	// on InstructionStream::IsWeakObjectInOptimizedCode.
	inline void set(int index, Tagged<Object> value);

	DECL_CAST(DeoptimizationLiteralArray)

	OBJECT_CONSTRUCTORS(DeoptimizationLiteralArray, TrustedWeakFixedArray);
	};

	// The DeoptimizationFrameTranslation is the on-heap representation of
	// translations created during code generation in a (zone-allocated)
	// DeoptimizationFrameTranslationBuilder. The translation specifies how to
	// transform an optimized frame back into one or more unoptimized frames.
	enum class TranslationOpcode;
	class DeoptimizationFrameTranslation : public TrustedByteArray {
	public:
	DECL_CAST(DeoptimizationFrameTranslation)

	struct FrameCount {
	int total_frame_count;
	int js_frame_count;
	};

	class Iterator;

	#ifdef V8_USE_ZLIB
	// Constants describing compressed DeoptimizationFrameTranslation layout. Only
	// relevant if
	// --turbo-compress-frame-translation is enabled.
	static constexpr int kUncompressedSizeOffset = 0;
	static constexpr int kUncompressedSizeSize = kInt32Size;
	static constexpr int kCompressedDataOffset =
	kUncompressedSizeOffset + kUncompressedSizeSize;
	static constexpr int kDeoptimizationFrameTranslationElementSize = kInt32Size;
	#endif // V8_USE_ZLIB

	inline uint32_t get_int(int offset) const;
	inline void set_int(int offset, uint32_t value);

	#ifdef ENABLE_DISASSEMBLER
	void PrintFrameTranslation(
	std::ostream& os, int index,
	Tagged<DeoptimizationLiteralArray> literal_array) const;
	#endif

	OBJECT_CONSTRUCTORS(DeoptimizationFrameTranslation, TrustedByteArray);
	};

	class DeoptTranslationIterator {
	public:
	DeoptTranslationIterator(base::Vector<const uint8_t> buffer, int index);

	int32_t NextOperand();

	uint32_t NextOperandUnsigned();

	DeoptimizationFrameTranslation::FrameCount EnterBeginOpcode();

	TranslationOpcode NextOpcode();

	TranslationOpcode SeekNextJSFrame();
	TranslationOpcode SeekNextFrame();

	bool HasNextOpcode() const;

	void SkipOperands(int n) {
	for (int i = 0; i < n; i++) NextOperand();
	}

	private:
	TranslationOpcode NextOpcodeAtPreviousIndex();
	uint32_t NextUnsignedOperandAtPreviousIndex();
	void SkipOpcodeAndItsOperandsAtPreviousIndex();

	std::vector<int32_t> uncompressed_contents_;
	const base::Vector<const uint8_t> buffer_;
	int index_;

	// This decrementing counter indicates how many more times to read operations
	// from the previous translation before continuing to move the index forward.
	int remaining_ops_to_use_from_previous_translation_ = 0;

	// An index into buffer_ for operations starting at a previous BEGIN, which
	// can be used to read operations referred to by MATCH_PREVIOUS_TRANSLATION.
	int previous_index_ = 0;

	// When starting a new MATCH_PREVIOUS_TRANSLATION operation, we'll need to
	// advance the previous_index_ by this many steps.
	int ops_since_previous_index_was_updated_ = 0;
	};

	// Iterator over the deoptimization values. The iterator is not GC-safe.
	class DeoptimizationFrameTranslation::Iterator
	: public DeoptTranslationIterator {
	public:
	Iterator(Tagged<DeoptimizationFrameTranslation> buffer, int index);
	DisallowGarbageCollection no_gc_;
	};

	// DeoptimizationData is a fixed array used to hold the deoptimization data for
	// optimized code. It also contains information about functions that were
	// inlined. If N different functions were inlined then the first N elements of
	// the literal array will contain these functions.
	//
	// It can be empty.
	class DeoptimizationData : public ProtectedFixedArray {
	public:
	// Layout description. Indices in the array.
	static const int kFrameTranslationIndex = 0;
	static const int kInlinedFunctionCountIndex = 1;
	static const int kLiteralArrayIndex = 2;
	static const int kOsrBytecodeOffsetIndex = 3;
	static const int kOsrPcOffsetIndex = 4;
	static const int kOptimizationIdIndex = 5;
	static const int kSharedFunctionInfoWrapperIndex = 6;
	static const int kInliningPositionsIndex = 7;
	static const int kDeoptExitStartIndex = 8;
	static const int kEagerDeoptCountIndex = 9;
	static const int kLazyDeoptCountIndex = 10;
	static const int kFirstDeoptEntryIndex = 11;

	// Offsets of deopt entry elements relative to the start of the entry.
	static const int kBytecodeOffsetRawOffset = 0;
	static const int kTranslationIndexOffset = 1;
	static const int kPcOffset = 2;
	#ifdef DEBUG
	static const int kNodeIdOffset = 3;
	static const int kDeoptEntrySize = 4;
	#else // DEBUG
	static const int kDeoptEntrySize = 3;
	#endif // DEBUG

	// Simple element accessors.
	#define DECL_ELEMENT_ACCESSORS(name, type) \
	inline type name() const; \
	inline void Set##name(type value);

	DECL_ELEMENT_ACCESSORS(FrameTranslation,
	Tagged<DeoptimizationFrameTranslation>)
	DECL_ELEMENT_ACCESSORS(InlinedFunctionCount, Tagged<Smi>)
	DECL_ELEMENT_ACCESSORS(LiteralArray, Tagged<DeoptimizationLiteralArray>)
	DECL_ELEMENT_ACCESSORS(OsrBytecodeOffset, Tagged<Smi>)
	DECL_ELEMENT_ACCESSORS(OsrPcOffset, Tagged<Smi>)
	DECL_ELEMENT_ACCESSORS(OptimizationId, Tagged<Smi>)
	DECL_ELEMENT_ACCESSORS(SharedFunctionInfoWrapper, Tagged<Object>)
	DECL_ELEMENT_ACCESSORS(InliningPositions,
	Tagged<TrustedPodArray<InliningPosition>>)
	DECL_ELEMENT_ACCESSORS(DeoptExitStart, Tagged<Smi>)
	DECL_ELEMENT_ACCESSORS(EagerDeoptCount, Tagged<Smi>)
	DECL_ELEMENT_ACCESSORS(LazyDeoptCount, Tagged<Smi>)

	#undef DECL_ELEMENT_ACCESSORS

	inline Tagged<Object> SharedFunctionInfo() const;

	// Accessors for elements of the ith deoptimization entry.
	#define DECL_ENTRY_ACCESSORS(name, type) \
	inline type name(int i) const; \
	inline void Set##name(int i, type value);

	DECL_ENTRY_ACCESSORS(BytecodeOffsetRaw, Tagged<Smi>)
	DECL_ENTRY_ACCESSORS(TranslationIndex, Tagged<Smi>)
	DECL_ENTRY_ACCESSORS(Pc, Tagged<Smi>)
	#ifdef DEBUG
	DECL_ENTRY_ACCESSORS(NodeId, Tagged<Smi>)
	#endif // DEBUG

	#undef DECL_ENTRY_ACCESSORS

	// In case the innermost frame is a builtin continuation stub, then this field
	// actually contains the builtin id. See uses of
	// `Builtins::GetBuiltinFromBytecodeOffset`.
	// TODO(olivf): Add some validation that callers do not misinterpret the
	// result.
	inline BytecodeOffset GetBytecodeOffsetOrBuiltinContinuationId(int i) const;

	inline void SetBytecodeOffset(int i, BytecodeOffset value);

	inline int DeoptCount() const;

	static const int kNotInlinedIndex = -1;

	// Returns the inlined function at the given position in LiteralArray, or the
	// outer function if index == kNotInlinedIndex.
	Tagged<class SharedFunctionInfo> GetInlinedFunction(int index);

	// Allocates a DeoptimizationData.
	static Handle<DeoptimizationData> New(Isolate* isolate,
	int deopt_entry_count);
	static Handle<DeoptimizationData> New(LocalIsolate* isolate,
	int deopt_entry_count);

	// Return an empty DeoptimizationData.
	V8_EXPORT_PRIVATE static Handle<DeoptimizationData> Empty(Isolate* isolate);
	V8_EXPORT_PRIVATE static Handle<DeoptimizationData> Empty(
	LocalIsolate* isolate);

	DECL_CAST(DeoptimizationData)

	#ifdef DEBUG
	void Verify(Handle<BytecodeArray> bytecode) const;
	#endif
	#ifdef ENABLE_DISASSEMBLER
	void PrintDeoptimizationData(std::ostream& os) const;
	#endif

	private:
	static int IndexForEntry(int i) {
	return kFirstDeoptEntryIndex + (i * kDeoptEntrySize);
	}

	static int LengthFor(int entry_count) { return IndexForEntry(entry_count); }

	OBJECT_CONSTRUCTORS(DeoptimizationData, ProtectedFixedArray);
	};

	} // namespace internal
	} // namespace v8

	#include "src/objects/object-macros-undef.h"

	#endif // V8_OBJECTS_DEOPTIMIZATION_DATA_H_