// Copyright 2017 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_CODE_H_
#define V8_OBJECTS_CODE_H_
#include "src/base/bit-field.h"
#include "src/codegen/handler-table.h"
#include "src/deoptimizer/translation-array.h"
#include "src/objects/code-kind.h"
#include "src/objects/contexts.h"
#include "src/objects/fixed-array.h"
#include "src/objects/heap-object.h"
#include "src/objects/objects.h"
#include "src/objects/shared-function-info.h"
#include "src/objects/struct.h"
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
namespace v8 {
namespace internal {
class ByteArray;
class BytecodeArray;
class CodeDataContainer;
class CodeDesc;
namespace interpreter {
class Register;
} // namespace interpreter
// CodeDataContainer is a container for all mutable fields associated with its
// referencing {Code} object. Since {Code} objects reside on write-protected
// pages within the heap, its header fields need to be immutable. There always
// is a 1-to-1 relation between {Code} and {CodeDataContainer}, the referencing
// field {Code::code_data_container} itself is immutable.
class CodeDataContainer : public HeapObject {
public:
NEVER_READ_ONLY_SPACE
DECL_ACCESSORS(next_code_link, Object)
DECL_INT_ACCESSORS(kind_specific_flags)
// Clear uninitialized padding space. This ensures that the snapshot content
// is deterministic.
inline void clear_padding();
DECL_CAST(CodeDataContainer)
// Dispatched behavior.
DECL_PRINTER(CodeDataContainer)
DECL_VERIFIER(CodeDataContainer)
// Layout description.
#define CODE_DATA_FIELDS(V) \
/* Weak pointer fields. */ \
V(kPointerFieldsStrongEndOffset, 0) \
V(kNextCodeLinkOffset, kTaggedSize) \
V(kPointerFieldsWeakEndOffset, 0) \
/* Raw data fields. */ \
V(kKindSpecificFlagsOffset, kInt32Size) \
V(kUnalignedSize, OBJECT_POINTER_PADDING(kUnalignedSize)) \
/* Total size. */ \
V(kSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, CODE_DATA_FIELDS)
#undef CODE_DATA_FIELDS
class BodyDescriptor;
OBJECT_CONSTRUCTORS(CodeDataContainer, HeapObject);
};
// Code describes objects with on-the-fly generated machine code.
class Code : public HeapObject {
public:
NEVER_READ_ONLY_SPACE
// Opaque data type for encapsulating code flags like kind, inline
// cache state, and arguments count.
using Flags = uint32_t;
// All Code objects have the following layout:
//
// +--------------------------+
// | header |
// | padded to code alignment |
// +--------------------------+ <-- raw_body_start()
// | instructions | == raw_instruction_start()
// | ... |
// | padded to meta alignment | see kMetadataAlignment
// +--------------------------+ <-- raw_instruction_end()
// | metadata | == raw_metadata_start() (MS)
// | ... |
// | | <-- MS + handler_table_offset()
// | | <-- MS + constant_pool_offset()
// | | <-- MS + code_comments_offset()
// | | <-- MS + unwinding_info_offset()
// | padded to obj alignment |
// +--------------------------+ <-- raw_metadata_end() == raw_body_end()
// | padded to code alignment |
// +--------------------------+
//
// In other words, the variable-size 'body' consists of 'instructions' and
// 'metadata'.
//
// Note the accessor functions below may be prefixed with 'raw'. In this case,
// raw accessors (e.g. raw_instruction_start) always refer to the on-heap
// Code object, while camel-case accessors (e.g. InstructionStart) may refer
// to an off-heap area in the case of embedded builtins.
//
// Embedded builtins are on-heap Code objects, with an out-of-line body
// section. The on-heap Code object contains an essentially empty body
// section, while accessors, as mentioned above, redirect to the off-heap
// area. Metadata table offsets remain relative to MetadataStart(), i.e. they
// point into the off-heap metadata section. The off-heap layout is described
// in detail in the EmbeddedData class, but at a high level one can assume a
// dedicated, out-of-line, instruction and metadata section for each embedded
// builtin *in addition* to the on-heap Code object:
//
// +--------------------------+ <-- InstructionStart()
// | off-heap instructions |
// | ... |
// +--------------------------+ <-- InstructionEnd()
//
// +--------------------------+ <-- MetadataStart() (MS)
// | off-heap metadata |
// | ... | <-- MS + handler_table_offset()
// | | <-- MS + constant_pool_offset()
// | | <-- MS + code_comments_offset()
// | | <-- MS + unwinding_info_offset()
// +--------------------------+ <-- MetadataEnd()
// Constants for use in static asserts, stating whether the body is adjacent,
// i.e. instructions and metadata areas are adjacent.
static constexpr bool kOnHeapBodyIsContiguous = true;
static constexpr bool kOffHeapBodyIsContiguous = false;
static constexpr bool kBodyIsContiguous =
kOnHeapBodyIsContiguous && kOffHeapBodyIsContiguous;
inline Address raw_body_start() const;
inline Address raw_body_end() const;
inline int raw_body_size() const;
inline Address raw_instruction_start() const;
inline Address InstructionStart() const;
V8_EXPORT_PRIVATE Address OffHeapInstructionStart() const;
inline Address raw_instruction_end() const;
inline Address InstructionEnd() const;
V8_EXPORT_PRIVATE Address OffHeapInstructionEnd() const;
// When builtins un-embedding is enabled for the Isolate
// (see Isolate::is_short_builtin_calls_enabled()) then both embedded and
// un-embedded builtins might be exeuted and thus two kinds of |pc|s might
// appear on the stack.
// Unlike the paremeterless versions of the functions above the below variants
// ensure that the instruction start correspond to the given |pc| value.
// Thus for off-heap trampoline Code objects the result might be the
// instruction start/end of the embedded code stream or of un-embedded one.
// For normal Code objects these functions just return the
// raw_instruction_start/end() values.
// TODO(11527): remove these versions once the full solution is ready.
inline Address InstructionStart(Isolate* isolate, Address pc) const;
V8_EXPORT_PRIVATE Address OffHeapInstructionStart(Isolate* isolate,
Address pc) const;
inline Address InstructionEnd(Isolate* isolate, Address pc) const;
V8_EXPORT_PRIVATE Address OffHeapInstructionEnd(Isolate* isolate,
Address pc) const;
// Computes offset of the |pc| from the instruction start. The |pc| must
// belong to this code.
inline int GetOffsetFromInstructionStart(Isolate* isolate, Address pc) const;
inline int raw_instruction_size() const;
inline void set_raw_instruction_size(int value);
inline int InstructionSize() const;
V8_EXPORT_PRIVATE int OffHeapInstructionSize() const;
inline Address raw_metadata_start() const;
inline Address MetadataStart() const;
V8_EXPORT_PRIVATE Address OffHeapMetadataStart() const;
inline Address raw_metadata_end() const;
inline Address MetadataEnd() const;
V8_EXPORT_PRIVATE Address OffHeapMetadataEnd() const;
inline int raw_metadata_size() const;
inline void set_raw_metadata_size(int value);
inline int MetadataSize() const;
int OffHeapMetadataSize() const;
// The metadata section is aligned to this value.
static constexpr int kMetadataAlignment = kIntSize;
// [safepoint_table_offset]: The offset where the safepoint table starts.
inline int safepoint_table_offset() const { return 0; }
Address SafepointTableAddress() const;
int safepoint_table_size() const;
bool has_safepoint_table() const;
// [handler_table_offset]: The offset where the exception handler table
// starts.
inline int handler_table_offset() const;
inline void set_handler_table_offset(int offset);
Address HandlerTableAddress() const;
int handler_table_size() const;
bool has_handler_table() const;
// [constant_pool offset]: Offset of the constant pool.
inline int constant_pool_offset() const;
inline void set_constant_pool_offset(int offset);
inline Address constant_pool() const;
int constant_pool_size() const;
bool has_constant_pool() const;
// [code_comments_offset]: Offset of the code comment section.
inline int code_comments_offset() const;
inline void set_code_comments_offset(int offset);
inline Address code_comments() const;
V8_EXPORT_PRIVATE int code_comments_size() const;
V8_EXPORT_PRIVATE bool has_code_comments() const;
// [unwinding_info_offset]: Offset of the unwinding info section.
inline int32_t unwinding_info_offset() const;
inline void set_unwinding_info_offset(int32_t offset);
inline Address unwinding_info_start() const;
inline Address unwinding_info_end() const;
inline int unwinding_info_size() const;
inline bool has_unwinding_info() const;
#ifdef ENABLE_DISASSEMBLER
const char* GetName(Isolate* isolate) const;
V8_EXPORT_PRIVATE void Disassemble(const char* name, std::ostream& os,
Isolate* isolate,
Address current_pc = kNullAddress);
#endif
// [relocation_info]: Code relocation information
DECL_ACCESSORS(relocation_info, ByteArray)
// This function should be called only from GC.
void ClearEmbeddedObjects(Heap* heap);
// [deoptimization_data]: Array containing data for deopt.
DECL_ACCESSORS(deoptimization_data, FixedArray)
// [source_position_table]: ByteArray for the source positions table for
// non-baseline code.
DECL_ACCESSORS(source_position_table, ByteArray)
// [bytecode_offset_table]: ByteArray for the bytecode offset for baseline
// code.
DECL_ACCESSORS(bytecode_offset_table, ByteArray)
// If source positions have not been collected or an exception has been thrown
// this will return empty_byte_array.
inline ByteArray SourcePositionTable(SharedFunctionInfo sfi) const;
// [code_data_container]: A container indirection for all mutable fields.
DECL_RELEASE_ACQUIRE_ACCESSORS(code_data_container, CodeDataContainer)
// [next_code_link]: Link for lists of optimized or deoptimized code.
// Note that this field is stored in the {CodeDataContainer} to be mutable.
inline Object next_code_link() const;
inline void set_next_code_link(Object value);
// Unchecked accessors to be used during GC.
inline ByteArray unchecked_relocation_info() const;
inline int relocation_size() const;
// [kind]: Access to specific code kind.
inline CodeKind kind() const;
inline bool is_optimized_code() const;
inline bool is_wasm_code() const;
// Testers for interpreter builtins.
inline bool is_interpreter_trampoline_builtin() const;
// Testers for baseline builtins.
inline bool is_baseline_trampoline_builtin() const;
inline bool is_baseline_leave_frame_builtin() const;
// Tells whether the code checks the optimization marker in the function's
// feedback vector.
inline bool checks_optimization_marker() const;
// Tells whether the outgoing parameters of this code are tagged pointers.
inline bool has_tagged_outgoing_params() const;
// [is_turbofanned]: Tells whether the code object was generated by the
// TurboFan optimizing compiler.
inline bool is_turbofanned() const;
// [can_have_weak_objects]: If CodeKindIsOptimizedJSFunction(kind), tells
// whether the embedded objects in code should be treated weakly.
inline bool can_have_weak_objects() const;
inline void set_can_have_weak_objects(bool value);
// [builtin_index]: For builtins, tells which builtin index the code object
// has. The builtin index is a non-negative integer for builtins, and
// Builtins::kNoBuiltinId (-1) otherwise.
inline int builtin_index() const;
inline void set_builtin_index(int id);
inline bool is_builtin() const;
inline unsigned inlined_bytecode_size() const;
inline void set_inlined_bytecode_size(unsigned size);
inline bool has_safepoint_info() const;
// [stack_slots]: If {has_safepoint_info()}, the number of stack slots
// reserved in the code prologue.
inline int stack_slots() const;
// [marked_for_deoptimization]: If CodeKindCanDeoptimize(kind), tells whether
// the code is going to be deoptimized.
inline bool marked_for_deoptimization() const;
inline void set_marked_for_deoptimization(bool flag);
// [deoptimization_count]: If CodeKindCanDeoptimize(kind). In turboprop we
// retain the deoptimized code on soft deopts for a certain number of soft
// deopts. This field keeps track of the number of deoptimizations we have
// seen so far.
inline int deoptimization_count() const;
inline void increment_deoptimization_count();
// [embedded_objects_cleared]: If CodeKindIsOptimizedJSFunction(kind), tells
// whether the embedded objects in the code marked for deoptimization were
// cleared. Note that embedded_objects_cleared() implies
// marked_for_deoptimization().
inline bool embedded_objects_cleared() const;
inline void set_embedded_objects_cleared(bool flag);
// [deopt_already_counted]: If CodeKindCanDeoptimize(kind), tells whether
// the code was already deoptimized.
inline bool deopt_already_counted() const;
inline void set_deopt_already_counted(bool flag);
// [is_promise_rejection]: For kind BUILTIN tells whether the
// exception thrown by the code will lead to promise rejection or
// uncaught if both this and is_exception_caught is set.
// Use GetBuiltinCatchPrediction to access this.
inline void set_is_promise_rejection(bool flag);
// [is_exception_caught]: For kind BUILTIN tells whether the
// exception thrown by the code will be caught internally or
// uncaught if both this and is_promise_rejection is set.
// Use GetBuiltinCatchPrediction to access this.
inline void set_is_exception_caught(bool flag);
// [is_off_heap_trampoline]: For kind BUILTIN tells whether
// this is a trampoline to an off-heap builtin.
inline bool is_off_heap_trampoline() const;
// Get the safepoint entry for the given pc.
SafepointEntry GetSafepointEntry(Isolate* isolate, Address pc);
// The entire code object including its header is copied verbatim to the
// snapshot so that it can be written in one, fast, memcpy during
// deserialization. The deserializer will overwrite some pointers, rather
// like a runtime linker, but the random allocation addresses used in the
// mksnapshot process would still be present in the unlinked snapshot data,
// which would make snapshot production non-reproducible. This method wipes
// out the to-be-overwritten header data for reproducible snapshots.
inline void WipeOutHeader();
// Clear uninitialized padding space. This ensures that the snapshot content
// is deterministic. Depending on the V8 build mode there could be no padding.
inline void clear_padding();
// Initialize the flags field. Similar to clear_padding above this ensure that
// the snapshot content is deterministic.
inline void initialize_flags(CodeKind kind, bool is_turbofanned,
int stack_slots, bool is_off_heap_trampoline);
// Convert a target address into a code object.
static inline Code GetCodeFromTargetAddress(Address address);
// Convert an entry address into an object.
static inline Code GetObjectFromEntryAddress(Address location_of_address);
// Returns the size of code and its metadata. This includes the size of code
// relocation information, deoptimization data.
inline int SizeIncludingMetadata() const;
// Returns the address of the first relocation info (read backwards!).
inline byte* relocation_start() const;
// Returns the address right after the relocation info (read backwards!).
inline byte* relocation_end() const;
// Code entry point.
inline Address entry() const;
// Returns true if pc is inside this object's instructions.
inline bool contains(Isolate* isolate, Address pc);
// Relocate the code by delta bytes. Called to signal that this code
// object has been moved by delta bytes.
void Relocate(intptr_t delta);
// Migrate code from desc without flushing the instruction cache.
void CopyFromNoFlush(Heap* heap, const CodeDesc& desc);
// Copy the RelocInfo portion of |desc| to |dest|. The ByteArray must be
// exactly the same size as the RelocInfo in |desc|.
static inline void CopyRelocInfoToByteArray(ByteArray dest,
const CodeDesc& desc);
inline uintptr_t GetBaselineStartPCForBytecodeOffset(int bytecode_offset,
BytecodeArray bytecodes);
inline uintptr_t GetBaselineEndPCForBytecodeOffset(int bytecode_offset,
BytecodeArray bytecodes);
// Returns the PC of the next bytecode in execution order.
// If the bytecode at the given offset is JumpLoop, the PC of the jump target
// is returned. Other jumps are not allowed.
// For other bytecodes this is equivalent to
// GetBaselineEndPCForBytecodeOffset.
inline uintptr_t GetBaselinePCForNextExecutedBytecode(
int bytecode_offset, BytecodeArray bytecodes);
inline int GetBytecodeOffsetForBaselinePC(Address baseline_pc,
BytecodeArray bytecodes);
// Flushes the instruction cache for the executable instructions of this code
// object. Make sure to call this while the code is still writable.
void FlushICache() const;
// Returns the object size for a given body (used for allocation).
static int SizeFor(int body_size) {
return RoundUp(kHeaderSize + body_size, kCodeAlignment);
}
DECL_CAST(Code)
// Dispatched behavior.
inline int CodeSize() const;
DECL_PRINTER(Code)
DECL_VERIFIER(Code)
bool CanDeoptAt(Isolate* isolate, Address pc);
void SetMarkedForDeoptimization(const char* reason);
inline HandlerTable::CatchPrediction GetBuiltinCatchPrediction();
bool IsIsolateIndependent(Isolate* isolate);
bool IsNativeContextIndependent(Isolate* isolate);
inline bool CanContainWeakObjects();
inline bool IsWeakObject(HeapObject object);
static inline bool IsWeakObjectInOptimizedCode(HeapObject object);
// Returns false if this is an embedded builtin Code object that's in
// read_only_space and hence doesn't have execute permissions.
inline bool IsExecutable();
// Returns true if the function is inlined in the code.
bool Inlines(SharedFunctionInfo sfi);
class OptimizedCodeIterator;
// Layout description.
#define CODE_FIELDS(V) \
V(kRelocationInfoOffset, kTaggedSize) \
V(kDeoptimizationDataOffset, kTaggedSize) \
V(kPositionTableOffset, kTaggedSize) \
V(kCodeDataContainerOffset, kTaggedSize) \
/* Data or code not directly visited by GC directly starts here. */ \
/* The serializer needs to copy bytes starting from here verbatim. */ \
/* Objects embedded into code is visited via reloc info. */ \
V(kDataStart, 0) \
V(kInstructionSizeOffset, kIntSize) \
V(kMetadataSizeOffset, kIntSize) \
V(kFlagsOffset, kInt32Size) \
V(kBuiltinIndexOffset, kIntSize) \
V(kInlinedBytecodeSizeOffset, kIntSize) \
/* Offsets describing inline metadata tables, relative to MetadataStart. */ \
V(kHandlerTableOffsetOffset, kIntSize) \
V(kConstantPoolOffsetOffset, \
FLAG_enable_embedded_constant_pool ? kIntSize : 0) \
V(kCodeCommentsOffsetOffset, kIntSize) \
V(kUnwindingInfoOffsetOffset, kInt32Size) \
V(kUnalignedHeaderSize, 0) \
/* Add padding to align the instruction start following right after */ \
/* the Code object header. */ \
V(kOptionalPaddingOffset, CODE_POINTER_PADDING(kOptionalPaddingOffset)) \
V(kHeaderSize, 0)
DEFINE_FIELD_OFFSET_CONSTANTS(HeapObject::kHeaderSize, CODE_FIELDS)
#undef CODE_FIELDS
// This documents the amount of free space we have in each Code object header
// due to padding for code alignment.
#if V8_TARGET_ARCH_ARM64
static constexpr int kHeaderPaddingSize = COMPRESS_POINTERS_BOOL ? 12 : 24;
#elif V8_TARGET_ARCH_MIPS64
static constexpr int kHeaderPaddingSize = 24;
#elif V8_TARGET_ARCH_X64
static constexpr int kHeaderPaddingSize = COMPRESS_POINTERS_BOOL ? 12 : 24;
#elif V8_TARGET_ARCH_ARM
static constexpr int kHeaderPaddingSize = 12;
#elif V8_TARGET_ARCH_IA32
static constexpr int kHeaderPaddingSize = 12;
#elif V8_TARGET_ARCH_MIPS
static constexpr int kHeaderPaddingSize = 12;
#elif V8_TARGET_ARCH_PPC64
static constexpr int kHeaderPaddingSize =
FLAG_enable_embedded_constant_pool ? (COMPRESS_POINTERS_BOOL ? 8 : 20)
: (COMPRESS_POINTERS_BOOL ? 12 : 24);
#elif V8_TARGET_ARCH_S390X
static constexpr int kHeaderPaddingSize = COMPRESS_POINTERS_BOOL ? 12 : 24;
#elif V8_TARGET_ARCH_RISCV64
static constexpr int kHeaderPaddingSize = 24;
#else
#error Unknown architecture.
#endif
STATIC_ASSERT(FIELD_SIZE(kOptionalPaddingOffset) == kHeaderPaddingSize);
class BodyDescriptor;
// Flags layout. base::BitField<type, shift, size>.
#define CODE_FLAGS_BIT_FIELDS(V, _) \
V(KindField, CodeKind, 4, _) \
V(IsTurbofannedField, bool, 1, _) \
V(StackSlotsField, int, 24, _) \
V(IsOffHeapTrampoline, bool, 1, _)
DEFINE_BIT_FIELDS(CODE_FLAGS_BIT_FIELDS)
#undef CODE_FLAGS_BIT_FIELDS
STATIC_ASSERT(kCodeKindCount <= KindField::kNumValues);
STATIC_ASSERT(CODE_FLAGS_BIT_FIELDS_Ranges::kBitsCount == 30);
STATIC_ASSERT(CODE_FLAGS_BIT_FIELDS_Ranges::kBitsCount <=
FIELD_SIZE(kFlagsOffset) * kBitsPerByte);
// KindSpecificFlags layout.
#define CODE_KIND_SPECIFIC_FLAGS_BIT_FIELDS(V, _) \
V(MarkedForDeoptimizationField, bool, 1, _) \
V(EmbeddedObjectsClearedField, bool, 1, _) \
V(DeoptAlreadyCountedField, bool, 1, _) \
V(CanHaveWeakObjectsField, bool, 1, _) \
V(IsPromiseRejectionField, bool, 1, _) \
V(IsExceptionCaughtField, bool, 1, _) \
V(DeoptCountField, int, 4, _)
DEFINE_BIT_FIELDS(CODE_KIND_SPECIFIC_FLAGS_BIT_FIELDS)
#undef CODE_KIND_SPECIFIC_FLAGS_BIT_FIELDS
STATIC_ASSERT(CODE_KIND_SPECIFIC_FLAGS_BIT_FIELDS_Ranges::kBitsCount == 10);
STATIC_ASSERT(CODE_KIND_SPECIFIC_FLAGS_BIT_FIELDS_Ranges::kBitsCount <=
FIELD_SIZE(CodeDataContainer::kKindSpecificFlagsOffset) *
kBitsPerByte);
// The {marked_for_deoptimization} field is accessed from generated code.
static const int kMarkedForDeoptimizationBit =
MarkedForDeoptimizationField::kShift;
static const int kArgumentsBits = 16;
// Reserve one argument count value as the "don't adapt arguments" sentinel.
static const int kMaxArguments = (1 << kArgumentsBits) - 2;
private:
friend class RelocIterator;
bool is_promise_rejection() const;
bool is_exception_caught() const;
enum BytecodeToPCPosition {
kPcAtStartOfBytecode,
// End of bytecode equals the start of the next bytecode.
// We need it when we deoptimize to the next bytecode (lazy deopt or deopt
// of non-topmost frame).
kPcAtEndOfBytecode
};
inline uintptr_t GetBaselinePCForBytecodeOffset(int bytecode_offset,
BytecodeToPCPosition position,
BytecodeArray bytecodes);
OBJECT_CONSTRUCTORS(Code, HeapObject);
};
class Code::OptimizedCodeIterator {
public:
explicit OptimizedCodeIterator(Isolate* isolate);
OptimizedCodeIterator(const OptimizedCodeIterator&) = delete;
OptimizedCodeIterator& operator=(const OptimizedCodeIterator&) = delete;
Code Next();
private:
NativeContext next_context_;
Code current_code_;
Isolate* isolate_;
DISALLOW_GARBAGE_COLLECTION(no_gc)
};
class AbstractCode : public HeapObject {
public:
NEVER_READ_ONLY_SPACE
int SourcePosition(int offset);
int SourceStatementPosition(int offset);
// Returns the address of the first instruction.
inline Address raw_instruction_start();
// Returns the address of the first instruction. For off-heap code objects
// this differs from instruction_start (which would point to the off-heap
// trampoline instead).
inline Address InstructionStart();
// Returns the address right after the last instruction.
inline Address raw_instruction_end();
// Returns the address right after the last instruction. For off-heap code
// objects this differs from instruction_end (which would point to the
// off-heap trampoline instead).
inline Address InstructionEnd();
// Returns the size of the code instructions.
inline int raw_instruction_size();
// Returns the size of the native instructions, including embedded
// data such as the safepoints table. For off-heap code objects
// this may differ from instruction_size in that this will return the size of
// the off-heap instruction stream rather than the on-heap trampoline located
// at instruction_start.
inline int InstructionSize();
// Return the source position table for interpreter code.
inline ByteArray SourcePositionTable(SharedFunctionInfo sfi);
void DropStackFrameCache();
// Returns the size of instructions and the metadata.
inline int SizeIncludingMetadata();
// Returns true if pc is inside this object's instructions.
inline bool contains(Address pc);
// Returns the kind of the code.
inline CodeKind kind();
DECL_CAST(AbstractCode)
inline Code GetCode();
inline BytecodeArray GetBytecodeArray();
// Max loop nesting marker used to postpose OSR. We don't take loop
// nesting that is deeper than 5 levels into account.
static const int kMaxLoopNestingMarker = 6;
OBJECT_CONSTRUCTORS(AbstractCode, HeapObject);
private:
inline ByteArray SourcePositionTableInternal();
};
// Dependent code is a singly linked list of weak fixed arrays. Each array
// contains weak pointers to code objects for one dependent group. The suffix of
// the array can be filled with the undefined value if the number of codes is
// less than the length of the array.
//
// +------+-----------------+--------+--------+-----+--------+-----------+-----+
// | next | count & group 1 | code 1 | code 2 | ... | code n | undefined | ... |
// +------+-----------------+--------+--------+-----+--------+-----------+-----+
// |
// V
// +------+-----------------+--------+--------+-----+--------+-----------+-----+
// | next | count & group 2 | code 1 | code 2 | ... | code m | undefined | ... |
// +------+-----------------+--------+--------+-----+--------+-----------+-----+
// |
// V
// empty_weak_fixed_array()
//
// The list of weak fixed arrays is ordered by dependency groups.
class DependentCode : public WeakFixedArray {
public:
DECL_CAST(DependentCode)
enum DependencyGroup {
// Group of code that embed a transition to this map, and depend on being
// deoptimized when the transition is replaced by a new version.
kTransitionGroup,
// Group of code that omit run-time prototype checks for prototypes
// described by this map. The group is deoptimized whenever the following
// conditions hold, possibly invalidating the assumptions embedded in the
// code:
// a) A fast-mode object described by this map changes shape (and
// transitions to a new map), or
// b) A dictionary-mode prototype described by this map changes shape, the
// const-ness of one of its properties changes, or its [[Prototype]]
// changes (only the latter causes a transition).
kPrototypeCheckGroup,
// Group of code that depends on global property values in property cells
// not being changed.
kPropertyCellChangedGroup,
// Group of code that omit run-time checks for field(s) introduced by
// this map, i.e. for the field type.
kFieldTypeGroup,
kFieldConstGroup,
kFieldRepresentationGroup,
// Group of code that omit run-time type checks for initial maps of
// constructors.
kInitialMapChangedGroup,
// Group of code that depends on tenuring information in AllocationSites
// not being changed.
kAllocationSiteTenuringChangedGroup,
// Group of code that depends on element transition information in
// AllocationSites not being changed.
kAllocationSiteTransitionChangedGroup
};
// Register a dependency of {code} on {object}, of the kind given by {group}.
V8_EXPORT_PRIVATE static void InstallDependency(Isolate* isolate,
const MaybeObjectHandle& code,
Handle<HeapObject> object,
DependencyGroup group);
void DeoptimizeDependentCodeGroup(DependencyGroup group);
bool MarkCodeForDeoptimization(DependencyGroup group);
// The following low-level accessors are exposed only for tests.
inline DependencyGroup group();
inline MaybeObject object_at(int i);
inline int count();
inline DependentCode next_link();
private:
static const char* DependencyGroupName(DependencyGroup group);
// Get/Set {object}'s {DependentCode}.
static DependentCode GetDependentCode(Handle<HeapObject> object);
static void SetDependentCode(Handle<HeapObject> object,
Handle<DependentCode> dep);
static Handle<DependentCode> New(Isolate* isolate, DependencyGroup group,
const MaybeObjectHandle& object,
Handle<DependentCode> next);
static Handle<DependentCode> EnsureSpace(Isolate* isolate,
Handle<DependentCode> entries);
static Handle<DependentCode> InsertWeakCode(Isolate* isolate,
Handle<DependentCode> entries,
DependencyGroup group,
const MaybeObjectHandle& code);
// Compact by removing cleared weak cells and return true if there was
// any cleared weak cell.
bool Compact();
static int Grow(int number_of_entries) {
if (number_of_entries < 5) return number_of_entries + 1;
return number_of_entries * 5 / 4;
}
static const int kGroupCount = kAllocationSiteTransitionChangedGroup + 1;
static const int kNextLinkIndex = 0;
static const int kFlagsIndex = 1;
static const int kCodesStartIndex = 2;
inline void set_next_link(DependentCode next);
inline void set_count(int value);
inline void set_object_at(int i, MaybeObject object);
inline void clear_at(int i);
inline void copy(int from, int to);
inline int flags();
inline void set_flags(int flags);
using GroupField = base::BitField<int, 0, 5>;
using CountField = base::BitField<int, 5, 27>;
STATIC_ASSERT(kGroupCount <= GroupField::kMax + 1);
OBJECT_CONSTRUCTORS(DependentCode, WeakFixedArray);
};
// BytecodeArray represents a sequence of interpreter bytecodes.
class BytecodeArray : public FixedArrayBase {
public:
enum Age {
kNoAgeBytecodeAge = 0,
kQuadragenarianBytecodeAge,
kQuinquagenarianBytecodeAge,
kSexagenarianBytecodeAge,
kSeptuagenarianBytecodeAge,
kOctogenarianBytecodeAge,
kAfterLastBytecodeAge,
kFirstBytecodeAge = kNoAgeBytecodeAge,
kLastBytecodeAge = kAfterLastBytecodeAge - 1,
kBytecodeAgeCount = kAfterLastBytecodeAge - kFirstBytecodeAge - 1,
kIsOldBytecodeAge = kSexagenarianBytecodeAge
};
static constexpr int SizeFor(int length) {
return OBJECT_POINTER_ALIGN(kHeaderSize + length);
}
// Setter and getter
inline byte get(int index) const;
inline void set(int index, byte value);
// Returns data start address.
inline Address GetFirstBytecodeAddress();
// Accessors for frame size.
inline int32_t frame_size() const;
inline void set_frame_size(int32_t frame_size);
// Accessor for register count (derived from frame_size).
inline int register_count() const;
// Accessors for parameter count (including implicit 'this' receiver).
inline int32_t parameter_count() const;
inline void set_parameter_count(int32_t number_of_parameters);
// Register used to pass the incoming new.target or generator object from the
// fucntion call.
inline interpreter::Register incoming_new_target_or_generator_register()
const;
inline void set_incoming_new_target_or_generator_register(
interpreter::Register incoming_new_target_or_generator_register);
// Accessors for OSR loop nesting level.
inline int osr_loop_nesting_level() const;
inline void set_osr_loop_nesting_level(int depth);
// Accessors for bytecode's code age.
inline Age bytecode_age() const;
inline void set_bytecode_age(Age age);
// Accessors for the constant pool.
DECL_ACCESSORS(constant_pool, FixedArray)
// Accessors for handler table containing offsets of exception handlers.
DECL_ACCESSORS(handler_table, ByteArray)
// Accessors for source position table. Can contain:
// * undefined (initial value)
// * empty_byte_array (for bytecode generated for functions that will never
// have source positions, e.g. native functions).
// * ByteArray (when source positions have been collected for the bytecode)
// * exception (when an error occurred while explicitly collecting source
// positions for pre-existing bytecode).
DECL_RELEASE_ACQUIRE_ACCESSORS(source_position_table, Object)
inline bool HasSourcePositionTable() const;
inline bool DidSourcePositionGenerationFail() const;
// If source positions have not been collected or an exception has been thrown
// this will return empty_byte_array.
inline ByteArray SourcePositionTable() const;
// Indicates that an attempt was made to collect source positions, but that it
// failed most likely due to stack exhaustion. When in this state
// |SourcePositionTable| will return an empty byte array rather than crashing
// as it would if no attempt was ever made to collect source positions.
inline void SetSourcePositionsFailedToCollect();
DECL_CAST(BytecodeArray)
// Dispatched behavior.
inline int BytecodeArraySize();
inline int raw_instruction_size();
// Returns the size of bytecode and its metadata. This includes the size of
// bytecode, constant pool, source position table, and handler table.
inline int SizeIncludingMetadata();
DECL_PRINTER(BytecodeArray)
DECL_VERIFIER(BytecodeArray)
V8_EXPORT_PRIVATE void Disassemble(std::ostream& os);
void CopyBytecodesTo(BytecodeArray to);
// Bytecode aging
V8_EXPORT_PRIVATE bool IsOld() const;
V8_EXPORT_PRIVATE void MakeOlder();
// Clear uninitialized padding space. This ensures that the snapshot content
// is deterministic.
inline void clear_padding();
// Layout description.
DEFINE_FIELD_OFFSET_CONSTANTS(FixedArrayBase::kHeaderSize,
TORQUE_GENERATED_BYTECODE_ARRAY_FIELDS)
// InterpreterEntryTrampoline expects these fields to be next to each other
// and writes a 16-bit value to reset them.
STATIC_ASSERT(BytecodeArray::kBytecodeAgeOffset ==
kOsrNestingLevelOffset + kCharSize);
// Maximal memory consumption for a single BytecodeArray.
static const int kMaxSize = 512 * MB;
// Maximal length of a single BytecodeArray.
static const int kMaxLength = kMaxSize - kHeaderSize;
class BodyDescriptor;
OBJECT_CONSTRUCTORS(BytecodeArray, FixedArrayBase);
};
// 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 FixedArray {
public:
// Layout description. Indices in the array.
static const int kTranslationByteArrayIndex = 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 kSharedFunctionInfoIndex = 6;
static const int kInliningPositionsIndex = 7;
static const int kDeoptExitStartIndex = 8;
static const int kEagerSoftAndBailoutDeoptCountIndex = 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;
static const int kDeoptEntrySize = 3;
// Simple element accessors.
#define DECL_ELEMENT_ACCESSORS(name, type) \
inline type name() const; \
inline void Set##name(type value);
DECL_ELEMENT_ACCESSORS(TranslationByteArray, TranslationArray)
DECL_ELEMENT_ACCESSORS(InlinedFunctionCount, Smi)
DECL_ELEMENT_ACCESSORS(LiteralArray, FixedArray)
DECL_ELEMENT_ACCESSORS(OsrBytecodeOffset, Smi)
DECL_ELEMENT_ACCESSORS(OsrPcOffset, Smi)
DECL_ELEMENT_ACCESSORS(OptimizationId, Smi)
DECL_ELEMENT_ACCESSORS(SharedFunctionInfo, Object)
DECL_ELEMENT_ACCESSORS(InliningPositions, PodArray<InliningPosition>)
DECL_ELEMENT_ACCESSORS(DeoptExitStart, Smi)
DECL_ELEMENT_ACCESSORS(EagerSoftAndBailoutDeoptCount, Smi)
DECL_ELEMENT_ACCESSORS(LazyDeoptCount, Smi)
#undef DECL_ELEMENT_ACCESSORS
// 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, Smi)
DECL_ENTRY_ACCESSORS(TranslationIndex, Smi)
DECL_ENTRY_ACCESSORS(Pc, Smi)
#undef DECL_ENTRY_ACCESSORS
inline BytecodeOffset GetBytecodeOffset(int i);
inline void SetBytecodeOffset(int i, BytecodeOffset value);
inline int DeoptCount();
static const int kNotInlinedIndex = -1;
// Returns the inlined function at the given position in LiteralArray, or the
// outer function if index == kNotInlinedIndex.
class SharedFunctionInfo GetInlinedFunction(int index);
// Allocates a DeoptimizationData.
static Handle<DeoptimizationData> New(Isolate* isolate, int deopt_entry_count,
AllocationType allocation);
// Return an empty DeoptimizationData.
V8_EXPORT_PRIVATE static Handle<DeoptimizationData> Empty(Isolate* isolate);
DECL_CAST(DeoptimizationData)
#ifdef ENABLE_DISASSEMBLER
void DeoptimizationDataPrint(std::ostream& os); // NOLINT
#endif
private:
static int IndexForEntry(int i) {
return kFirstDeoptEntryIndex + (i * kDeoptEntrySize);
}
static int LengthFor(int entry_count) { return IndexForEntry(entry_count); }
OBJECT_CONSTRUCTORS(DeoptimizationData, FixedArray);
};
} // namespace internal
} // namespace v8
#include "src/objects/object-macros-undef.h"
#endif // V8_OBJECTS_CODE_H_