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// Copyright 2006-2010 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_HEAP_INL_H_
#define V8_HEAP_INL_H_
#include "heap.h"
#include "objects.h"
#include "v8-counters.h"
namespace v8 {
namespace internal {
int Heap::MaxObjectSizeInPagedSpace() {
return Page::kMaxHeapObjectSize;
}
MaybeObject* Heap::AllocateStringFromUtf8(Vector<const char> str,
PretenureFlag pretenure) {
// Check for ASCII first since this is the common case.
if (String::IsAscii(str.start(), str.length())) {
// If the string is ASCII, we do not need to convert the characters
// since UTF8 is backwards compatible with ASCII.
return AllocateStringFromAscii(str, pretenure);
}
// Non-ASCII and we need to decode.
return AllocateStringFromUtf8Slow(str, pretenure);
}
MaybeObject* Heap::AllocateSymbol(Vector<const char> str,
int chars,
uint32_t hash_field) {
unibrow::Utf8InputBuffer<> buffer(str.start(),
static_cast<unsigned>(str.length()));
return AllocateInternalSymbol(&buffer, chars, hash_field);
}
MaybeObject* Heap::AllocateAsciiSymbol(Vector<const char> str,
uint32_t hash_field) {
if (str.length() > SeqAsciiString::kMaxLength) {
return Failure::OutOfMemoryException();
}
// Compute map and object size.
Map* map = ascii_symbol_map();
int size = SeqAsciiString::SizeFor(str.length());
// Allocate string.
Object* result;
{ MaybeObject* maybe_result = (size > MaxObjectSizeInPagedSpace())
? lo_space_->AllocateRaw(size)
: old_data_space_->AllocateRaw(size);
if (!maybe_result->ToObject(&result)) return maybe_result;
}
reinterpret_cast<HeapObject*>(result)->set_map(map);
// Set length and hash fields of the allocated string.
String* answer = String::cast(result);
answer->set_length(str.length());
answer->set_hash_field(hash_field);
ASSERT_EQ(size, answer->Size());
// Fill in the characters.
memcpy(answer->address() + SeqAsciiString::kHeaderSize,
str.start(), str.length());
return answer;
}
MaybeObject* Heap::AllocateTwoByteSymbol(Vector<const uc16> str,
uint32_t hash_field) {
if (str.length() > SeqTwoByteString::kMaxLength) {
return Failure::OutOfMemoryException();
}
// Compute map and object size.
Map* map = symbol_map();
int size = SeqTwoByteString::SizeFor(str.length());
// Allocate string.
Object* result;
{ MaybeObject* maybe_result = (size > MaxObjectSizeInPagedSpace())
? lo_space_->AllocateRaw(size)
: old_data_space_->AllocateRaw(size);
if (!maybe_result->ToObject(&result)) return maybe_result;
}
reinterpret_cast<HeapObject*>(result)->set_map(map);
// Set length and hash fields of the allocated string.
String* answer = String::cast(result);
answer->set_length(str.length());
answer->set_hash_field(hash_field);
ASSERT_EQ(size, answer->Size());
// Fill in the characters.
memcpy(answer->address() + SeqTwoByteString::kHeaderSize,
str.start(), str.length() * kUC16Size);
return answer;
}
MaybeObject* Heap::CopyFixedArray(FixedArray* src) {
return CopyFixedArrayWithMap(src, src->map());
}
MaybeObject* Heap::AllocateRaw(int size_in_bytes,
AllocationSpace space,
AllocationSpace retry_space) {
ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
ASSERT(space != NEW_SPACE ||
retry_space == OLD_POINTER_SPACE ||
retry_space == OLD_DATA_SPACE ||
retry_space == LO_SPACE);
#ifdef DEBUG
if (FLAG_gc_interval >= 0 &&
!disallow_allocation_failure_ &&
Heap::allocation_timeout_-- <= 0) {
return Failure::RetryAfterGC(space);
}
Counters::objs_since_last_full.Increment();
Counters::objs_since_last_young.Increment();
#endif
MaybeObject* result;
if (NEW_SPACE == space) {
result = new_space_.AllocateRaw(size_in_bytes);
if (always_allocate() && result->IsFailure()) {
space = retry_space;
} else {
return result;
}
}
if (OLD_POINTER_SPACE == space) {
result = old_pointer_space_->AllocateRaw(size_in_bytes);
} else if (OLD_DATA_SPACE == space) {
result = old_data_space_->AllocateRaw(size_in_bytes);
} else if (CODE_SPACE == space) {
result = code_space_->AllocateRaw(size_in_bytes);
} else if (LO_SPACE == space) {
result = lo_space_->AllocateRaw(size_in_bytes);
} else if (CELL_SPACE == space) {
result = cell_space_->AllocateRaw(size_in_bytes);
} else {
ASSERT(MAP_SPACE == space);
result = map_space_->AllocateRaw(size_in_bytes);
}
if (result->IsFailure()) old_gen_exhausted_ = true;
return result;
}
MaybeObject* Heap::NumberFromInt32(int32_t value) {
if (Smi::IsValid(value)) return Smi::FromInt(value);
// Bypass NumberFromDouble to avoid various redundant checks.
return AllocateHeapNumber(FastI2D(value));
}
MaybeObject* Heap::NumberFromUint32(uint32_t value) {
if ((int32_t)value >= 0 && Smi::IsValid((int32_t)value)) {
return Smi::FromInt((int32_t)value);
}
// Bypass NumberFromDouble to avoid various redundant checks.
return AllocateHeapNumber(FastUI2D(value));
}
void Heap::FinalizeExternalString(String* string) {
ASSERT(string->IsExternalString());
v8::String::ExternalStringResourceBase** resource_addr =
reinterpret_cast<v8::String::ExternalStringResourceBase**>(
reinterpret_cast<byte*>(string) +
ExternalString::kResourceOffset -
kHeapObjectTag);
// Dispose of the C++ object if it has not already been disposed.
if (*resource_addr != NULL) {
(*resource_addr)->Dispose();
}
// Clear the resource pointer in the string.
*resource_addr = NULL;
}
MaybeObject* Heap::AllocateRawMap() {
#ifdef DEBUG
Counters::objs_since_last_full.Increment();
Counters::objs_since_last_young.Increment();
#endif
MaybeObject* result = map_space_->AllocateRaw(Map::kSize);
if (result->IsFailure()) old_gen_exhausted_ = true;
#ifdef DEBUG
if (!result->IsFailure()) {
// Maps have their own alignment.
CHECK((reinterpret_cast<intptr_t>(result) & kMapAlignmentMask) ==
static_cast<intptr_t>(kHeapObjectTag));
}
#endif
return result;
}
MaybeObject* Heap::AllocateRawCell() {
#ifdef DEBUG
Counters::objs_since_last_full.Increment();
Counters::objs_since_last_young.Increment();
#endif
MaybeObject* result = cell_space_->AllocateRaw(JSGlobalPropertyCell::kSize);
if (result->IsFailure()) old_gen_exhausted_ = true;
return result;
}
bool Heap::InNewSpace(Object* object) {
bool result = new_space_.Contains(object);
ASSERT(!result || // Either not in new space
gc_state_ != NOT_IN_GC || // ... or in the middle of GC
InToSpace(object)); // ... or in to-space (where we allocate).
return result;
}
bool Heap::InFromSpace(Object* object) {
return new_space_.FromSpaceContains(object);
}
bool Heap::InToSpace(Object* object) {
return new_space_.ToSpaceContains(object);
}
bool Heap::ShouldBePromoted(Address old_address, int object_size) {
// An object should be promoted if:
// - the object has survived a scavenge operation or
// - to space is already 25% full.
return old_address < new_space_.age_mark()
|| (new_space_.Size() + object_size) >= (new_space_.Capacity() >> 2);
}
void Heap::RecordWrite(Address address, int offset) {
if (new_space_.Contains(address)) return;
ASSERT(!new_space_.FromSpaceContains(address));
SLOW_ASSERT(Contains(address + offset));
Page::FromAddress(address)->MarkRegionDirty(address + offset);
}
void Heap::RecordWrites(Address address, int start, int len) {
if (new_space_.Contains(address)) return;
ASSERT(!new_space_.FromSpaceContains(address));
Page* page = Page::FromAddress(address);
page->SetRegionMarks(page->GetRegionMarks() |
page->GetRegionMaskForSpan(address + start, len * kPointerSize));
}
OldSpace* Heap::TargetSpace(HeapObject* object) {
InstanceType type = object->map()->instance_type();
AllocationSpace space = TargetSpaceId(type);
return (space == OLD_POINTER_SPACE)
? old_pointer_space_
: old_data_space_;
}
AllocationSpace Heap::TargetSpaceId(InstanceType type) {
// Heap numbers and sequential strings are promoted to old data space, all
// other object types are promoted to old pointer space. We do not use
// object->IsHeapNumber() and object->IsSeqString() because we already
// know that object has the heap object tag.
// These objects are never allocated in new space.
ASSERT(type != MAP_TYPE);
ASSERT(type != CODE_TYPE);
ASSERT(type != ODDBALL_TYPE);
ASSERT(type != JS_GLOBAL_PROPERTY_CELL_TYPE);
if (type < FIRST_NONSTRING_TYPE) {
// There are three string representations: sequential strings, cons
// strings, and external strings. Only cons strings contain
// non-map-word pointers to heap objects.
return ((type & kStringRepresentationMask) == kConsStringTag)
? OLD_POINTER_SPACE
: OLD_DATA_SPACE;
} else {
return (type <= LAST_DATA_TYPE) ? OLD_DATA_SPACE : OLD_POINTER_SPACE;
}
}
void Heap::CopyBlock(Address dst, Address src, int byte_size) {
ASSERT(IsAligned(byte_size, kPointerSize));
CopyWords(reinterpret_cast<Object**>(dst),
reinterpret_cast<Object**>(src),
byte_size / kPointerSize);
}
void Heap::CopyBlockToOldSpaceAndUpdateRegionMarks(Address dst,
Address src,
int byte_size) {
ASSERT(IsAligned(byte_size, kPointerSize));
Page* page = Page::FromAddress(dst);
uint32_t marks = page->GetRegionMarks();
for (int remaining = byte_size / kPointerSize;
remaining > 0;
remaining--) {
Memory::Object_at(dst) = Memory::Object_at(src);
if (Heap::InNewSpace(Memory::Object_at(dst))) {
marks |= page->GetRegionMaskForAddress(dst);
}
dst += kPointerSize;
src += kPointerSize;
}
page->SetRegionMarks(marks);
}
void Heap::MoveBlock(Address dst, Address src, int byte_size) {
ASSERT(IsAligned(byte_size, kPointerSize));
int size_in_words = byte_size / kPointerSize;
if ((dst < src) || (dst >= (src + size_in_words))) {
ASSERT((dst >= (src + size_in_words)) ||
((OffsetFrom(reinterpret_cast<Address>(src)) -
OffsetFrom(reinterpret_cast<Address>(dst))) >= kPointerSize));
Object** src_slot = reinterpret_cast<Object**>(src);
Object** dst_slot = reinterpret_cast<Object**>(dst);
Object** end_slot = src_slot + size_in_words;
while (src_slot != end_slot) {
*dst_slot++ = *src_slot++;
}
} else {
memmove(dst, src, byte_size);
}
}
void Heap::MoveBlockToOldSpaceAndUpdateRegionMarks(Address dst,
Address src,
int byte_size) {
ASSERT(IsAligned(byte_size, kPointerSize));
ASSERT((dst >= (src + byte_size)) ||
((OffsetFrom(src) - OffsetFrom(dst)) >= kPointerSize));
CopyBlockToOldSpaceAndUpdateRegionMarks(dst, src, byte_size);
}
void Heap::ScavengeObject(HeapObject** p, HeapObject* object) {
ASSERT(InFromSpace(object));
// We use the first word (where the map pointer usually is) of a heap
// object to record the forwarding pointer. A forwarding pointer can
// point to an old space, the code space, or the to space of the new
// generation.
MapWord first_word = object->map_word();
// If the first word is a forwarding address, the object has already been
// copied.
if (first_word.IsForwardingAddress()) {
*p = first_word.ToForwardingAddress();
return;
}
// Call the slow part of scavenge object.
return ScavengeObjectSlow(p, object);
}
bool Heap::CollectGarbage(AllocationSpace space) {
return CollectGarbage(space, SelectGarbageCollector(space));
}
MaybeObject* Heap::PrepareForCompare(String* str) {
// Always flatten small strings and force flattening of long strings
// after we have accumulated a certain amount we failed to flatten.
static const int kMaxAlwaysFlattenLength = 32;
static const int kFlattenLongThreshold = 16*KB;
const int length = str->length();
MaybeObject* obj = str->TryFlatten();
if (length <= kMaxAlwaysFlattenLength ||
unflattened_strings_length_ >= kFlattenLongThreshold) {
return obj;
}
if (obj->IsFailure()) {
unflattened_strings_length_ += length;
}
return str;
}
int Heap::AdjustAmountOfExternalAllocatedMemory(int change_in_bytes) {
ASSERT(HasBeenSetup());
int amount = amount_of_external_allocated_memory_ + change_in_bytes;
if (change_in_bytes >= 0) {
// Avoid overflow.
if (amount > amount_of_external_allocated_memory_) {
amount_of_external_allocated_memory_ = amount;
}
int amount_since_last_global_gc =
amount_of_external_allocated_memory_ -
amount_of_external_allocated_memory_at_last_global_gc_;
if (amount_since_last_global_gc > external_allocation_limit_) {
CollectAllGarbage(false);
}
} else {
// Avoid underflow.
if (amount >= 0) {
amount_of_external_allocated_memory_ = amount;
}
}
ASSERT(amount_of_external_allocated_memory_ >= 0);
return amount_of_external_allocated_memory_;
}
void Heap::SetLastScriptId(Object* last_script_id) {
roots_[kLastScriptIdRootIndex] = last_script_id;
}
#ifdef DEBUG
#define GC_GREEDY_CHECK() \
if (FLAG_gc_greedy) v8::internal::Heap::GarbageCollectionGreedyCheck()
#else
#define GC_GREEDY_CHECK() { }
#endif
// Calls the FUNCTION_CALL function and retries it up to three times
// to guarantee that any allocations performed during the call will
// succeed if there's enough memory.
// Warning: Do not use the identifiers __object__, __maybe_object__ or
// __scope__ in a call to this macro.
#define CALL_AND_RETRY(FUNCTION_CALL, RETURN_VALUE, RETURN_EMPTY) \
do { \
GC_GREEDY_CHECK(); \
MaybeObject* __maybe_object__ = FUNCTION_CALL; \
Object* __object__ = NULL; \
if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE; \
if (__maybe_object__->IsOutOfMemory()) { \
v8::internal::V8::FatalProcessOutOfMemory("CALL_AND_RETRY_0", true);\
} \
if (!__maybe_object__->IsRetryAfterGC()) RETURN_EMPTY; \
Heap::CollectGarbage( \
Failure::cast(__maybe_object__)->allocation_space()); \
__maybe_object__ = FUNCTION_CALL; \
if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE; \
if (__maybe_object__->IsOutOfMemory()) { \
v8::internal::V8::FatalProcessOutOfMemory("CALL_AND_RETRY_1", true);\
} \
if (!__maybe_object__->IsRetryAfterGC()) RETURN_EMPTY; \
Counters::gc_last_resort_from_handles.Increment(); \
Heap::CollectAllAvailableGarbage(); \
{ \
AlwaysAllocateScope __scope__; \
__maybe_object__ = FUNCTION_CALL; \
} \
if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE; \
if (__maybe_object__->IsOutOfMemory() || \
__maybe_object__->IsRetryAfterGC()) { \
/* TODO(1181417): Fix this. */ \
v8::internal::V8::FatalProcessOutOfMemory("CALL_AND_RETRY_2", true);\
} \
RETURN_EMPTY; \
} while (false)
#define CALL_HEAP_FUNCTION(FUNCTION_CALL, TYPE) \
CALL_AND_RETRY(FUNCTION_CALL, \
return Handle<TYPE>(TYPE::cast(__object__)), \
return Handle<TYPE>())
#define CALL_HEAP_FUNCTION_VOID(FUNCTION_CALL) \
CALL_AND_RETRY(FUNCTION_CALL, return, return)
#ifdef DEBUG
inline bool Heap::allow_allocation(bool new_state) {
bool old = allocation_allowed_;
allocation_allowed_ = new_state;
return old;
}
#endif
void ExternalStringTable::AddString(String* string) {
ASSERT(string->IsExternalString());
if (Heap::InNewSpace(string)) {
new_space_strings_.Add(string);
} else {
old_space_strings_.Add(string);
}
}
void ExternalStringTable::Iterate(ObjectVisitor* v) {
if (!new_space_strings_.is_empty()) {
Object** start = &new_space_strings_[0];
v->VisitPointers(start, start + new_space_strings_.length());
}
if (!old_space_strings_.is_empty()) {
Object** start = &old_space_strings_[0];
v->VisitPointers(start, start + old_space_strings_.length());
}
}
// Verify() is inline to avoid ifdef-s around its calls in release
// mode.
void ExternalStringTable::Verify() {
#ifdef DEBUG
for (int i = 0; i < new_space_strings_.length(); ++i) {
ASSERT(Heap::InNewSpace(new_space_strings_[i]));
ASSERT(new_space_strings_[i] != Heap::raw_unchecked_null_value());
}
for (int i = 0; i < old_space_strings_.length(); ++i) {
ASSERT(!Heap::InNewSpace(old_space_strings_[i]));
ASSERT(old_space_strings_[i] != Heap::raw_unchecked_null_value());
}
#endif
}
void ExternalStringTable::AddOldString(String* string) {
ASSERT(string->IsExternalString());
ASSERT(!Heap::InNewSpace(string));
old_space_strings_.Add(string);
}
void ExternalStringTable::ShrinkNewStrings(int position) {
new_space_strings_.Rewind(position);
Verify();
}
} } // namespace v8::internal
#endif // V8_HEAP_INL_H_