// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_V8GLOBALS_H_
#define V8_V8GLOBALS_H_
#include "globals.h"
#include "checks.h"
namespace v8 {
namespace internal {
// This file contains constants and global declarations related to the
// V8 system.
// Mask for the sign bit in a smi.
const intptr_t kSmiSignMask = kIntptrSignBit;
const int kObjectAlignmentBits = kPointerSizeLog2;
const intptr_t kObjectAlignment = 1 << kObjectAlignmentBits;
const intptr_t kObjectAlignmentMask = kObjectAlignment - 1;
// Desired alignment for pointers.
const intptr_t kPointerAlignment = (1 << kPointerSizeLog2);
const intptr_t kPointerAlignmentMask = kPointerAlignment - 1;
// Desired alignment for maps.
#if V8_HOST_ARCH_64_BIT
const intptr_t kMapAlignmentBits = kObjectAlignmentBits;
#else
const intptr_t kMapAlignmentBits = kObjectAlignmentBits + 3;
#endif
const intptr_t kMapAlignment = (1 << kMapAlignmentBits);
const intptr_t kMapAlignmentMask = kMapAlignment - 1;
// Desired alignment for generated code is 32 bytes (to improve cache line
// utilization).
const int kCodeAlignmentBits = 5;
const intptr_t kCodeAlignment = 1 << kCodeAlignmentBits;
const intptr_t kCodeAlignmentMask = kCodeAlignment - 1;
// Tag information for Failure.
const int kFailureTag = 3;
const int kFailureTagSize = 2;
const intptr_t kFailureTagMask = (1 << kFailureTagSize) - 1;
// Zap-value: The value used for zapping dead objects.
// Should be a recognizable hex value tagged as a failure.
#ifdef V8_HOST_ARCH_64_BIT
const Address kZapValue =
reinterpret_cast<Address>(V8_UINT64_C(0xdeadbeedbeadbeef));
const Address kHandleZapValue =
reinterpret_cast<Address>(V8_UINT64_C(0x1baddead0baddeaf));
const Address kFromSpaceZapValue =
reinterpret_cast<Address>(V8_UINT64_C(0x1beefdad0beefdaf));
const uint64_t kDebugZapValue = V8_UINT64_C(0xbadbaddbbadbaddb);
const uint64_t kSlotsZapValue = V8_UINT64_C(0xbeefdeadbeefdeef);
const uint64_t kFreeListZapValue = 0xfeed1eaffeed1eaf;
#else
const Address kZapValue = reinterpret_cast<Address>(0xdeadbeef);
const Address kHandleZapValue = reinterpret_cast<Address>(0xbaddeaf);
const Address kFromSpaceZapValue = reinterpret_cast<Address>(0xbeefdaf);
const uint32_t kSlotsZapValue = 0xbeefdeef;
const uint32_t kDebugZapValue = 0xbadbaddb;
const uint32_t kFreeListZapValue = 0xfeed1eaf;
#endif
// Number of bits to represent the page size for paged spaces. The value of 20
// gives 1Mb bytes per page.
const int kPageSizeBits = 20;
// On Intel architecture, cache line size is 64 bytes.
// On ARM it may be less (32 bytes), but as far this constant is
// used for aligning data, it doesn't hurt to align on a greater value.
const int kProcessorCacheLineSize = 64;
// Constants relevant to double precision floating point numbers.
// If looking only at the top 32 bits, the QNaN mask is bits 19 to 30.
const uint32_t kQuietNaNHighBitsMask = 0xfff << (51 - 32);
// -----------------------------------------------------------------------------
// Forward declarations for frequently used classes
class AccessorInfo;
class Allocation;
class Arguments;
class Assembler;
class AssertNoAllocation;
class Code;
class CodeGenerator;
class CodeStub;
class Context;
class Debug;
class Debugger;
class DebugInfo;
class Descriptor;
class DescriptorArray;
class ExternalReference;
class FixedArray;
class FunctionTemplateInfo;
class MemoryChunk;
class SeededNumberDictionary;
class UnseededNumberDictionary;
class StringDictionary;
template <typename T> class Handle;
class Heap;
class HeapObject;
class IC;
class InterceptorInfo;
class JSArray;
class JSFunction;
class JSObject;
class LargeObjectSpace;
class LookupResult;
class MacroAssembler;
class Map;
class MapSpace;
class MarkCompactCollector;
class NewSpace;
class Object;
class MaybeObject;
class OldSpace;
class Foreign;
class Scope;
class ScopeInfo;
class Script;
class Smi;
template <typename Config, class Allocator = FreeStoreAllocationPolicy>
class SplayTree;
class String;
class Struct;
class Variable;
class RelocInfo;
class Deserializer;
class MessageLocation;
class ObjectGroup;
class TickSample;
class VirtualMemory;
class Mutex;
typedef bool (*WeakSlotCallback)(Object** pointer);
typedef bool (*WeakSlotCallbackWithHeap)(Heap* heap, Object** pointer);
// -----------------------------------------------------------------------------
// Miscellaneous
// NOTE: SpaceIterator depends on AllocationSpace enumeration values being
// consecutive.
enum AllocationSpace {
NEW_SPACE, // Semispaces collected with copying collector.
OLD_POINTER_SPACE, // May contain pointers to new space.
OLD_DATA_SPACE, // Must not have pointers to new space.
CODE_SPACE, // No pointers to new space, marked executable.
MAP_SPACE, // Only and all map objects.
CELL_SPACE, // Only and all cell objects.
LO_SPACE, // Promoted large objects.
FIRST_SPACE = NEW_SPACE,
LAST_SPACE = LO_SPACE,
FIRST_PAGED_SPACE = OLD_POINTER_SPACE,
LAST_PAGED_SPACE = CELL_SPACE
};
const int kSpaceTagSize = 3;
const int kSpaceTagMask = (1 << kSpaceTagSize) - 1;
// A flag that indicates whether objects should be pretenured when
// allocated (allocated directly into the old generation) or not
// (allocated in the young generation if the object size and type
// allows).
enum PretenureFlag { NOT_TENURED, TENURED };
enum GarbageCollector { SCAVENGER, MARK_COMPACTOR };
enum Executability { NOT_EXECUTABLE, EXECUTABLE };
enum VisitMode {
VISIT_ALL,
VISIT_ALL_IN_SCAVENGE,
VISIT_ALL_IN_SWEEP_NEWSPACE,
VISIT_ONLY_STRONG
};
// Flag indicating whether code is built into the VM (one of the natives files).
enum NativesFlag { NOT_NATIVES_CODE, NATIVES_CODE };
// A CodeDesc describes a buffer holding instructions and relocation
// information. The instructions start at the beginning of the buffer
// and grow forward, the relocation information starts at the end of
// the buffer and grows backward.
//
// |<--------------- buffer_size ---------------->|
// |<-- instr_size -->| |<-- reloc_size -->|
// +==================+========+==================+
// | instructions | free | reloc info |
// +==================+========+==================+
// ^
// |
// buffer
struct CodeDesc {
byte* buffer;
int buffer_size;
int instr_size;
int reloc_size;
Assembler* origin;
};
// Callback function used for iterating objects in heap spaces,
// for example, scanning heap objects.
typedef int (*HeapObjectCallback)(HeapObject* obj);
// Callback function used for checking constraints when copying/relocating
// objects. Returns true if an object can be copied/relocated from its
// old_addr to a new_addr.
typedef bool (*ConstraintCallback)(Address new_addr, Address old_addr);
// Callback function on inline caches, used for iterating over inline caches
// in compiled code.
typedef void (*InlineCacheCallback)(Code* code, Address ic);
// State for inline cache call sites. Aliased as IC::State.
enum InlineCacheState {
// Has never been executed.
UNINITIALIZED,
// Has been executed but monomorhic state has been delayed.
PREMONOMORPHIC,
// Has been executed and only one receiver type has been seen.
MONOMORPHIC,
// Like MONOMORPHIC but check failed due to prototype.
MONOMORPHIC_PROTOTYPE_FAILURE,
// Multiple receiver types have been seen.
MEGAMORPHIC,
// Special states for debug break or step in prepare stubs.
DEBUG_BREAK,
DEBUG_PREPARE_STEP_IN
};
enum CheckType {
RECEIVER_MAP_CHECK,
STRING_CHECK,
NUMBER_CHECK,
BOOLEAN_CHECK
};
enum CallFunctionFlags {
NO_CALL_FUNCTION_FLAGS = 0,
// Receiver might implicitly be the global objects. If it is, the
// hole is passed to the call function stub.
RECEIVER_MIGHT_BE_IMPLICIT = 1 << 0,
// The call target is cached in the instruction stream.
RECORD_CALL_TARGET = 1 << 1
};
enum InlineCacheHolderFlag {
OWN_MAP, // For fast properties objects.
PROTOTYPE_MAP // For slow properties objects (except GlobalObjects).
};
// The Store Buffer (GC).
typedef enum {
kStoreBufferFullEvent,
kStoreBufferStartScanningPagesEvent,
kStoreBufferScanningPageEvent
} StoreBufferEvent;
typedef void (*StoreBufferCallback)(Heap* heap,
MemoryChunk* page,
StoreBufferEvent event);
// Whether to remove map transitions and constant transitions from a
// DescriptorArray.
enum TransitionFlag {
REMOVE_TRANSITIONS,
KEEP_TRANSITIONS
};
// Union used for fast testing of specific double values.
union DoubleRepresentation {
double value;
int64_t bits;
DoubleRepresentation(double x) { value = x; }
};
// Union used for customized checking of the IEEE double types
// inlined within v8 runtime, rather than going to the underlying
// platform headers and libraries
union IeeeDoubleLittleEndianArchType {
double d;
struct {
unsigned int man_low :32;
unsigned int man_high :20;
unsigned int exp :11;
unsigned int sign :1;
} bits;
};
union IeeeDoubleBigEndianArchType {
double d;
struct {
unsigned int sign :1;
unsigned int exp :11;
unsigned int man_high :20;
unsigned int man_low :32;
} bits;
};
// AccessorCallback
struct AccessorDescriptor {
MaybeObject* (*getter)(Object* object, void* data);
MaybeObject* (*setter)(JSObject* object, Object* value, void* data);
void* data;
};
// Logging and profiling. A StateTag represents a possible state of
// the VM. The logger maintains a stack of these. Creating a VMState
// object enters a state by pushing on the stack, and destroying a
// VMState object leaves a state by popping the current state from the
// stack.
#define STATE_TAG_LIST(V) \
V(JS) \
V(GC) \
V(COMPILER) \
V(OTHER) \
V(EXTERNAL)
enum StateTag {
#define DEF_STATE_TAG(name) name,
STATE_TAG_LIST(DEF_STATE_TAG)
#undef DEF_STATE_TAG
// Pseudo-types.
state_tag_count
};
// -----------------------------------------------------------------------------
// Macros
// Testers for test.
#define HAS_SMI_TAG(value) \
((reinterpret_cast<intptr_t>(value) & kSmiTagMask) == kSmiTag)
#define HAS_FAILURE_TAG(value) \
((reinterpret_cast<intptr_t>(value) & kFailureTagMask) == kFailureTag)
// OBJECT_POINTER_ALIGN returns the value aligned as a HeapObject pointer
#define OBJECT_POINTER_ALIGN(value) \
(((value) + kObjectAlignmentMask) & ~kObjectAlignmentMask)
// POINTER_SIZE_ALIGN returns the value aligned as a pointer.
#define POINTER_SIZE_ALIGN(value) \
(((value) + kPointerAlignmentMask) & ~kPointerAlignmentMask)
// MAP_POINTER_ALIGN returns the value aligned as a map pointer.
#define MAP_POINTER_ALIGN(value) \
(((value) + kMapAlignmentMask) & ~kMapAlignmentMask)
// CODE_POINTER_ALIGN returns the value aligned as a generated code segment.
#define CODE_POINTER_ALIGN(value) \
(((value) + kCodeAlignmentMask) & ~kCodeAlignmentMask)
// Support for tracking C++ memory allocation. Insert TRACK_MEMORY("Fisk")
// inside a C++ class and new and delete will be overloaded so logging is
// performed.
// This file (globals.h) is included before log.h, so we use direct calls to
// the Logger rather than the LOG macro.
#ifdef DEBUG
#define TRACK_MEMORY(name) \
void* operator new(size_t size) { \
void* result = ::operator new(size); \
Logger::NewEventStatic(name, result, size); \
return result; \
} \
void operator delete(void* object) { \
Logger::DeleteEventStatic(name, object); \
::operator delete(object); \
}
#else
#define TRACK_MEMORY(name)
#endif
// Feature flags bit positions. They are mostly based on the CPUID spec.
// (We assign CPUID itself to one of the currently reserved bits --
// feel free to change this if needed.)
// On X86/X64, values below 32 are bits in EDX, values above 32 are bits in ECX.
enum CpuFeature { SSE4_1 = 32 + 19, // x86
SSE3 = 32 + 0, // x86
SSE2 = 26, // x86
CMOV = 15, // x86
RDTSC = 4, // x86
CPUID = 10, // x86
VFP3 = 1, // ARM
ARMv7 = 2, // ARM
SAHF = 0, // x86
FPU = 1}; // MIPS
// Used to specify if a macro instruction must perform a smi check on tagged
// values.
enum SmiCheckType {
DONT_DO_SMI_CHECK,
DO_SMI_CHECK
};
// Used to specify whether a receiver is implicitly or explicitly
// provided to a call.
enum CallKind {
CALL_AS_METHOD,
CALL_AS_FUNCTION
};
enum ScopeType {
EVAL_SCOPE, // The top-level scope for an eval source.
FUNCTION_SCOPE, // The top-level scope for a function.
MODULE_SCOPE, // The scope introduced by a module literal
GLOBAL_SCOPE, // The top-level scope for a program or a top-level eval.
CATCH_SCOPE, // The scope introduced by catch.
BLOCK_SCOPE, // The scope introduced by a new block.
WITH_SCOPE // The scope introduced by with.
};
const uint32_t kHoleNanUpper32 = 0x7FFFFFFF;
const uint32_t kHoleNanLower32 = 0xFFFFFFFF;
const uint32_t kNaNOrInfinityLowerBoundUpper32 = 0x7FF00000;
const uint64_t kHoleNanInt64 =
(static_cast<uint64_t>(kHoleNanUpper32) << 32) | kHoleNanLower32;
const uint64_t kLastNonNaNInt64 =
(static_cast<uint64_t>(kNaNOrInfinityLowerBoundUpper32) << 32);
enum VariableMode {
// User declared variables:
VAR, // declared via 'var', and 'function' declarations
CONST, // declared via 'const' declarations
CONST_HARMONY, // declared via 'const' declarations in harmony mode
LET, // declared via 'let' declarations
// Variables introduced by the compiler:
DYNAMIC, // always require dynamic lookup (we don't know
// the declaration)
DYNAMIC_GLOBAL, // requires dynamic lookup, but we know that the
// variable is global unless it has been shadowed
// by an eval-introduced variable
DYNAMIC_LOCAL, // requires dynamic lookup, but we know that the
// variable is local and where it is unless it
// has been shadowed by an eval-introduced
// variable
INTERNAL, // like VAR, but not user-visible (may or may not
// be in a context)
TEMPORARY // temporary variables (not user-visible), never
// in a context
};
// ES6 Draft Rev3 10.2 specifies declarative environment records with mutable
// and immutable bindings that can be in two states: initialized and
// uninitialized. In ES5 only immutable bindings have these two states. When
// accessing a binding, it needs to be checked for initialization. However in
// the following cases the binding is initialized immediately after creation
// so the initialization check can always be skipped:
// 1. Var declared local variables.
// var foo;
// 2. A local variable introduced by a function declaration.
// function foo() {}
// 3. Parameters
// function x(foo) {}
// 4. Catch bound variables.
// try {} catch (foo) {}
// 6. Function variables of named function expressions.
// var x = function foo() {}
// 7. Implicit binding of 'this'.
// 8. Implicit binding of 'arguments' in functions.
//
// ES5 specified object environment records which are introduced by ES elements
// such as Program and WithStatement that associate identifier bindings with the
// properties of some object. In the specification only mutable bindings exist
// (which may be non-writable) and have no distinct initialization step. However
// V8 allows const declarations in global code with distinct creation and
// initialization steps which are represented by non-writable properties in the
// global object. As a result also these bindings need to be checked for
// initialization.
//
// The following enum specifies a flag that indicates if the binding needs a
// distinct initialization step (kNeedsInitialization) or if the binding is
// immediately initialized upon creation (kCreatedInitialized).
enum InitializationFlag {
kNeedsInitialization,
kCreatedInitialized
};
enum ClearExceptionFlag {
KEEP_EXCEPTION,
CLEAR_EXCEPTION
};
} } // namespace v8::internal
#endif // V8_V8GLOBALS_H_