Initial export.
git-svn-id: http://v8.googlecode.com/svn/trunk@2 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
diff --git a/src/heap.cc b/src/heap.cc
new file mode 100644
index 0000000..cd0417d
--- /dev/null
+++ b/src/heap.cc
@@ -0,0 +1,2910 @@
+// Copyright 2006-2008 Google Inc. 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.
+
+#include "v8.h"
+
+#include "accessors.h"
+#include "api.h"
+#include "bootstrapper.h"
+#include "codegen-inl.h"
+#include "debug.h"
+#include "global-handles.h"
+#include "jsregexp.h"
+#include "mark-compact.h"
+#include "natives.h"
+#include "scanner.h"
+#include "scopeinfo.h"
+#include "v8threads.h"
+
+namespace v8 { namespace internal {
+
+#ifdef DEBUG
+DEFINE_bool(gc_greedy, false, "perform GC prior to some allocations");
+DEFINE_bool(gc_verbose, false, "print stuff during garbage collection");
+DEFINE_bool(heap_stats, false, "report heap statistics before and after GC");
+DEFINE_bool(code_stats, false, "report code statistics after GC");
+DEFINE_bool(verify_heap, false, "verify heap pointers before and after GC");
+DEFINE_bool(print_handles, false, "report handles after GC");
+DEFINE_bool(print_global_handles, false, "report global handles after GC");
+DEFINE_bool(print_rset, false, "print remembered sets before GC");
+#endif
+
+DEFINE_int(new_space_size, 0, "size of (each semispace in) the new generation");
+DEFINE_int(old_space_size, 0, "size of the old generation");
+
+DEFINE_bool(gc_global, false, "always perform global GCs");
+DEFINE_int(gc_interval, -1, "garbage collect after <n> allocations");
+DEFINE_bool(trace_gc, false,
+ "print one trace line following each garbage collection");
+
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+DECLARE_bool(log_gc);
+#endif
+
+
+#define ROOT_ALLOCATION(type, name) type* Heap::name##_;
+ ROOT_LIST(ROOT_ALLOCATION)
+#undef ROOT_ALLOCATION
+
+
+#define STRUCT_ALLOCATION(NAME, Name, name) Map* Heap::name##_map_;
+ STRUCT_LIST(STRUCT_ALLOCATION)
+#undef STRUCT_ALLOCATION
+
+
+#define SYMBOL_ALLOCATION(name, string) String* Heap::name##_;
+ SYMBOL_LIST(SYMBOL_ALLOCATION)
+#undef SYMBOL_ALLOCATION
+
+
+NewSpace* Heap::new_space_ = NULL;
+OldSpace* Heap::old_space_ = NULL;
+OldSpace* Heap::code_space_ = NULL;
+MapSpace* Heap::map_space_ = NULL;
+LargeObjectSpace* Heap::lo_space_ = NULL;
+
+int Heap::promoted_space_limit_ = 0;
+int Heap::old_gen_exhausted_ = false;
+
+// semispace_size_ should be a power of 2 and old_generation_size_ should be
+// a multiple of Page::kPageSize.
+int Heap::semispace_size_ = 1*MB;
+int Heap::old_generation_size_ = 512*MB;
+int Heap::initial_semispace_size_ = 256*KB;
+
+GCCallback Heap::global_gc_prologue_callback_ = NULL;
+GCCallback Heap::global_gc_epilogue_callback_ = NULL;
+
+// Variables set based on semispace_size_ and old_generation_size_ in
+// ConfigureHeap.
+int Heap::young_generation_size_ = 0; // Will be 2 * semispace_size_.
+
+// Double the new space after this many scavenge collections.
+int Heap::new_space_growth_limit_ = 8;
+int Heap::scavenge_count_ = 0;
+Heap::HeapState Heap::gc_state_ = NOT_IN_GC;
+
+#ifdef DEBUG
+bool Heap::allocation_allowed_ = true;
+int Heap::mc_count_ = 0;
+int Heap::gc_count_ = 0;
+
+int Heap::allocation_timeout_ = 0;
+bool Heap::disallow_allocation_failure_ = false;
+#endif // DEBUG
+
+
+int Heap::Capacity() {
+ if (!HasBeenSetup()) return 0;
+
+ return new_space_->Capacity() +
+ old_space_->Capacity() +
+ code_space_->Capacity() +
+ map_space_->Capacity();
+}
+
+
+int Heap::Available() {
+ if (!HasBeenSetup()) return 0;
+
+ return new_space_->Available() +
+ old_space_->Available() +
+ code_space_->Available() +
+ map_space_->Available();
+}
+
+
+bool Heap::HasBeenSetup() {
+ return new_space_ != NULL &&
+ old_space_ != NULL &&
+ code_space_ != NULL &&
+ map_space_ != NULL &&
+ lo_space_ != NULL;
+}
+
+
+GarbageCollector Heap::SelectGarbageCollector(AllocationSpace space) {
+ // Is global GC requested?
+ if (space != NEW_SPACE || FLAG_gc_global) {
+ Counters::gc_compactor_caused_by_request.Increment();
+ return MARK_COMPACTOR;
+ }
+
+ // Is enough data promoted to justify a global GC?
+ if (PromotedSpaceSize() > promoted_space_limit_) {
+ Counters::gc_compactor_caused_by_promoted_data.Increment();
+ return MARK_COMPACTOR;
+ }
+
+ // Have allocation in OLD and LO failed?
+ if (old_gen_exhausted_) {
+ Counters::gc_compactor_caused_by_oldspace_exhaustion.Increment();
+ return MARK_COMPACTOR;
+ }
+
+ // Is there enough space left in OLD to guarantee that a scavenge can
+ // succeed?
+ //
+ // Note that old_space_->MaxAvailable() undercounts the memory available
+ // for object promotion. It counts only the bytes that the memory
+ // allocator has not yet allocated from the OS and assigned to any space,
+ // and does not count available bytes already in the old space or code
+ // space. Undercounting is safe---we may get an unrequested full GC when
+ // a scavenge would have succeeded.
+ if (old_space_->MaxAvailable() <= new_space_->Size()) {
+ Counters::gc_compactor_caused_by_oldspace_exhaustion.Increment();
+ return MARK_COMPACTOR;
+ }
+
+ // Default
+ return SCAVENGER;
+}
+
+
+// TODO(1238405): Combine the infrastructure for --heap-stats and
+// --log-gc to avoid the complicated preprocessor and flag testing.
+#if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
+void Heap::ReportStatisticsBeforeGC() {
+ // Heap::ReportHeapStatistics will also log NewSpace statistics when
+ // compiled with ENABLE_LOGGING_AND_PROFILING and --log-gc is set. The
+ // following logic is used to avoid double logging.
+#if defined(DEBUG) && defined(ENABLE_LOGGING_AND_PROFILING)
+ if (FLAG_heap_stats || FLAG_log_gc) new_space_->CollectStatistics();
+ if (FLAG_heap_stats) {
+ ReportHeapStatistics("Before GC");
+ } else if (FLAG_log_gc) {
+ new_space_->ReportStatistics();
+ }
+ if (FLAG_heap_stats || FLAG_log_gc) new_space_->ClearHistograms();
+#elif defined(DEBUG)
+ if (FLAG_heap_stats) {
+ new_space_->CollectStatistics();
+ ReportHeapStatistics("Before GC");
+ new_space_->ClearHistograms();
+ }
+#elif defined(ENABLE_LOGGING_AND_PROFILING)
+ if (FLAG_log_gc) {
+ new_space_->CollectStatistics();
+ new_space_->ReportStatistics();
+ new_space_->ClearHistograms();
+ }
+#endif
+}
+
+
+// TODO(1238405): Combine the infrastructure for --heap-stats and
+// --log-gc to avoid the complicated preprocessor and flag testing.
+void Heap::ReportStatisticsAfterGC() {
+ // Similar to the before GC, we use some complicated logic to ensure that
+ // NewSpace statistics are logged exactly once when --log-gc is turned on.
+#if defined(DEBUG) && defined(ENABLE_LOGGING_AND_PROFILING)
+ if (FLAG_heap_stats) {
+ ReportHeapStatistics("After GC");
+ } else if (FLAG_log_gc) {
+ new_space_->ReportStatistics();
+ }
+#elif defined(DEBUG)
+ if (FLAG_heap_stats) ReportHeapStatistics("After GC");
+#elif defined(ENABLE_LOGGING_AND_PROFILING)
+ if (FLAG_log_gc) new_space_->ReportStatistics();
+#endif
+}
+#endif // defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
+
+
+void Heap::GarbageCollectionPrologue() {
+ RegExpImpl::NewSpaceCollectionPrologue();
+#ifdef DEBUG
+ ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
+ allow_allocation(false);
+ gc_count_++;
+
+ if (FLAG_verify_heap) {
+ Verify();
+ }
+
+ if (FLAG_gc_verbose) Print();
+
+ if (FLAG_print_rset) {
+ // By definition, code space does not have remembered set bits that we
+ // care about.
+ old_space_->PrintRSet();
+ map_space_->PrintRSet();
+ lo_space_->PrintRSet();
+ }
+#endif
+
+#if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
+ ReportStatisticsBeforeGC();
+#endif
+}
+
+int Heap::SizeOfObjects() {
+ return new_space_->Size() +
+ old_space_->Size() +
+ code_space_->Size() +
+ map_space_->Size() +
+ lo_space_->Size();
+}
+
+void Heap::GarbageCollectionEpilogue() {
+#ifdef DEBUG
+ allow_allocation(true);
+ ZapFromSpace();
+
+ if (FLAG_verify_heap) {
+ Verify();
+ }
+
+ if (FLAG_print_global_handles) GlobalHandles::Print();
+ if (FLAG_print_handles) PrintHandles();
+ if (FLAG_gc_verbose) Print();
+ if (FLAG_code_stats) ReportCodeStatistics("After GC");
+#endif
+
+ Counters::alive_after_last_gc.Set(SizeOfObjects());
+
+ SymbolTable* symbol_table = SymbolTable::cast(Heap::symbol_table_);
+ Counters::symbol_table_capacity.Set(symbol_table->Capacity());
+ Counters::number_of_symbols.Set(symbol_table->NumberOfElements());
+#if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
+ ReportStatisticsAfterGC();
+#endif
+}
+
+
+// GCTracer collects and prints ONE line after each garbage collector
+// invocation IFF --trace_gc is used.
+
+class GCTracer BASE_EMBEDDED {
+ public:
+ GCTracer() : start_time_(0.0), start_size_(0.0) {
+ if (!FLAG_trace_gc) return;
+ start_time_ = OS::TimeCurrentMillis();
+ start_size_ = SizeOfHeapObjects();
+ }
+
+ ~GCTracer() {
+ if (!FLAG_trace_gc) return;
+ // Printf ONE line iff flag is set.
+ PrintF("%s %.1f -> %.1f MB, %d ms.\n",
+ CollectorString(),
+ start_size_, SizeOfHeapObjects(),
+ static_cast<int>(OS::TimeCurrentMillis() - start_time_));
+ }
+
+ // Sets the collector.
+ void set_collector(GarbageCollector collector) {
+ collector_ = collector;
+ }
+
+ private:
+
+ // Returns a string matching the collector.
+ const char* CollectorString() {
+ switch (collector_) {
+ case SCAVENGER:
+ return "Scavenge";
+ case MARK_COMPACTOR:
+ return MarkCompactCollector::HasCompacted() ? "Mark-compact"
+ : "Mark-sweep";
+ }
+ return "Unknown GC";
+ }
+
+ // Returns size of object in heap (in MB).
+ double SizeOfHeapObjects() {
+ return (static_cast<double>(Heap::SizeOfObjects())) / MB;
+ }
+
+ double start_time_; // Timestamp set in the constructor.
+ double start_size_; // Size of objects in heap set in constructor.
+ GarbageCollector collector_; // Type of collector.
+};
+
+
+
+bool Heap::CollectGarbage(int requested_size, AllocationSpace space) {
+ // The VM is in the GC state until exiting this function.
+ VMState state(GC);
+
+#ifdef DEBUG
+ // Reset the allocation timeout to the GC interval, but make sure to
+ // allow at least a few allocations after a collection. The reason
+ // for this is that we have a lot of allocation sequences and we
+ // assume that a garbage collection will allow the subsequent
+ // allocation attempts to go through.
+ allocation_timeout_ = Max(6, FLAG_gc_interval);
+#endif
+
+ { GCTracer tracer;
+ GarbageCollectionPrologue();
+
+ GarbageCollector collector = SelectGarbageCollector(space);
+ tracer.set_collector(collector);
+
+ StatsRate* rate = (collector == SCAVENGER)
+ ? &Counters::gc_scavenger
+ : &Counters::gc_compactor;
+ rate->Start();
+ PerformGarbageCollection(space, collector);
+ rate->Stop();
+
+ GarbageCollectionEpilogue();
+ }
+
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+ if (FLAG_log_gc) HeapProfiler::WriteSample();
+#endif
+
+ switch (space) {
+ case NEW_SPACE:
+ return new_space_->Available() >= requested_size;
+ case OLD_SPACE:
+ return old_space_->Available() >= requested_size;
+ case CODE_SPACE:
+ return code_space_->Available() >= requested_size;
+ case MAP_SPACE:
+ return map_space_->Available() >= requested_size;
+ case LO_SPACE:
+ return lo_space_->Available() >= requested_size;
+ }
+ return false;
+}
+
+
+void Heap::PerformGarbageCollection(AllocationSpace space,
+ GarbageCollector collector) {
+ if (collector == MARK_COMPACTOR && global_gc_prologue_callback_) {
+ ASSERT(!allocation_allowed_);
+ global_gc_prologue_callback_();
+ }
+
+ if (collector == MARK_COMPACTOR) {
+ MarkCompact();
+
+ int promoted_space_size = PromotedSpaceSize();
+ promoted_space_limit_ =
+ promoted_space_size + Max(2 * MB, (promoted_space_size/100) * 35);
+ old_gen_exhausted_ = false;
+
+ // If we have used the mark-compact collector to collect the new
+ // space, and it has not compacted the new space, we force a
+ // separate scavenge collection. THIS IS A HACK. It covers the
+ // case where (1) a new space collection was requested, (2) the
+ // collector selection policy selected the mark-compact collector,
+ // and (3) the mark-compact collector policy selected not to
+ // compact the new space. In that case, there is no more (usable)
+ // free space in the new space after the collection compared to
+ // before.
+ if (space == NEW_SPACE && !MarkCompactCollector::HasCompacted()) {
+ Scavenge();
+ }
+ } else {
+ Scavenge();
+ }
+ Counters::objs_since_last_young.Set(0);
+
+ // Process weak handles post gc.
+ GlobalHandles::PostGarbageCollectionProcessing();
+
+ if (collector == MARK_COMPACTOR && global_gc_epilogue_callback_) {
+ ASSERT(!allocation_allowed_);
+ global_gc_epilogue_callback_();
+ }
+}
+
+
+void Heap::MarkCompact() {
+ gc_state_ = MARK_COMPACT;
+#ifdef DEBUG
+ mc_count_++;
+#endif
+ LOG(ResourceEvent("markcompact", "begin"));
+
+ MarkCompactPrologue();
+
+ MarkCompactCollector::CollectGarbage();
+
+ MarkCompactEpilogue();
+
+ LOG(ResourceEvent("markcompact", "end"));
+
+ gc_state_ = NOT_IN_GC;
+
+ Shrink();
+
+ Counters::objs_since_last_full.Set(0);
+}
+
+
+void Heap::MarkCompactPrologue() {
+ RegExpImpl::OldSpaceCollectionPrologue();
+ Top::MarkCompactPrologue();
+ ThreadManager::MarkCompactPrologue();
+}
+
+
+void Heap::MarkCompactEpilogue() {
+ Top::MarkCompactEpilogue();
+ ThreadManager::MarkCompactEpilogue();
+}
+
+
+Object* Heap::FindCodeObject(Address a) {
+ Object* obj = code_space_->FindObject(a);
+ if (obj->IsFailure()) {
+ obj = lo_space_->FindObject(a);
+ }
+ return obj;
+}
+
+
+// Helper class for copying HeapObjects
+class CopyVisitor: public ObjectVisitor {
+ public:
+
+ void VisitPointer(Object** p) {
+ CopyObject(p);
+ }
+
+ void VisitPointers(Object** start, Object** end) {
+ // Copy all HeapObject pointers in [start, end)
+ for (Object** p = start; p < end; p++) CopyObject(p);
+ }
+
+ private:
+ void CopyObject(Object** p) {
+ if (!Heap::InFromSpace(*p)) return;
+ Heap::CopyObject(reinterpret_cast<HeapObject**>(p));
+ }
+};
+
+
+// Shared state read by the scavenge collector and set by CopyObject.
+static Address promoted_top = NULL;
+
+
+#ifdef DEBUG
+// Visitor class to verify pointers in code space do not point into
+// new space.
+class VerifyCodeSpacePointersVisitor: public ObjectVisitor {
+ public:
+ void VisitPointers(Object** start, Object**end) {
+ for (Object** current = start; current < end; current++) {
+ if ((*current)->IsHeapObject()) {
+ ASSERT(!Heap::InNewSpace(HeapObject::cast(*current)));
+ }
+ }
+ }
+};
+#endif
+
+void Heap::Scavenge() {
+#ifdef DEBUG
+ if (FLAG_enable_slow_asserts) {
+ VerifyCodeSpacePointersVisitor v;
+ HeapObjectIterator it(code_space_);
+ while (it.has_next()) {
+ HeapObject* object = it.next();
+ if (object->IsCode()) {
+ Code::cast(object)->ConvertICTargetsFromAddressToObject();
+ }
+ object->Iterate(&v);
+ if (object->IsCode()) {
+ Code::cast(object)->ConvertICTargetsFromObjectToAddress();
+ }
+ }
+ }
+#endif
+
+ gc_state_ = SCAVENGE;
+
+ // Implements Cheney's copying algorithm
+ LOG(ResourceEvent("scavenge", "begin"));
+
+ scavenge_count_++;
+ if (new_space_->Capacity() < new_space_->MaximumCapacity() &&
+ scavenge_count_ > new_space_growth_limit_) {
+ // Double the size of the new space, and double the limit. The next
+ // doubling attempt will occur after the current new_space_growth_limit_
+ // more collections.
+ // TODO(1240712): NewSpace::Double has a return value which is
+ // ignored here.
+ new_space_->Double();
+ new_space_growth_limit_ *= 2;
+ }
+
+ // Flip the semispaces. After flipping, to space is empty, from space has
+ // live objects.
+ new_space_->Flip();
+ new_space_->ResetAllocationInfo();
+
+ // We need to sweep newly copied objects which can be in either the to space
+ // or the old space. For to space objects, we use a mark. Newly copied
+ // objects lie between the mark and the allocation top. For objects
+ // promoted to old space, we write their addresses downward from the top of
+ // the new space. Sweeping newly promoted objects requires an allocation
+ // pointer and a mark. Note that the allocation pointer 'top' actually
+ // moves downward from the high address in the to space.
+ //
+ // There is guaranteed to be enough room at the top of the to space for the
+ // addresses of promoted objects: every object promoted frees up its size in
+ // bytes from the top of the new space, and objects are at least one pointer
+ // in size. Using the new space to record promoted addresses makes the
+ // scavenge collector agnostic to the allocation strategy (eg, linear or
+ // free-list) used in old space.
+ Address new_mark = new_space_->ToSpaceLow();
+ Address promoted_mark = new_space_->ToSpaceHigh();
+ promoted_top = new_space_->ToSpaceHigh();
+
+ CopyVisitor copy_visitor;
+ // Copy roots.
+ IterateRoots(©_visitor);
+
+ // Copy objects reachable from the old generation. By definition, there
+ // are no intergenerational pointers in code space.
+ IterateRSet(old_space_, &CopyObject);
+ IterateRSet(map_space_, &CopyObject);
+ lo_space_->IterateRSet(&CopyObject);
+
+ bool has_processed_weak_pointers = false;
+
+ while (true) {
+ ASSERT(new_mark <= new_space_->top());
+ ASSERT(promoted_mark >= promoted_top);
+
+ // Copy objects reachable from newly copied objects.
+ while (new_mark < new_space_->top() || promoted_mark > promoted_top) {
+ // Sweep newly copied objects in the to space. The allocation pointer
+ // can change during sweeping.
+ Address previous_top = new_space_->top();
+ SemiSpaceIterator new_it(new_space_, new_mark);
+ while (new_it.has_next()) {
+ new_it.next()->Iterate(©_visitor);
+ }
+ new_mark = previous_top;
+
+ // Sweep newly copied objects in the old space. The promotion 'top'
+ // pointer could change during sweeping.
+ previous_top = promoted_top;
+ for (Address current = promoted_mark - kPointerSize;
+ current >= previous_top;
+ current -= kPointerSize) {
+ HeapObject* object = HeapObject::cast(Memory::Object_at(current));
+ object->Iterate(©_visitor);
+ UpdateRSet(object);
+ }
+ promoted_mark = previous_top;
+ }
+
+ if (has_processed_weak_pointers) break; // We are done.
+ // Copy objects reachable from weak pointers.
+ GlobalHandles::IterateWeakRoots(©_visitor);
+ has_processed_weak_pointers = true;
+ }
+
+ // Set age mark.
+ new_space_->set_age_mark(new_mark);
+
+ LOG(ResourceEvent("scavenge", "end"));
+
+ gc_state_ = NOT_IN_GC;
+}
+
+
+void Heap::ClearRSetRange(Address start, int size_in_bytes) {
+ uint32_t start_bit;
+ Address start_word_address =
+ Page::ComputeRSetBitPosition(start, 0, &start_bit);
+ uint32_t end_bit;
+ Address end_word_address =
+ Page::ComputeRSetBitPosition(start + size_in_bytes - kIntSize,
+ 0,
+ &end_bit);
+
+ // We want to clear the bits in the starting word starting with the
+ // first bit, and in the ending word up to and including the last
+ // bit. Build a pair of bitmasks to do that.
+ uint32_t start_bitmask = start_bit - 1;
+ uint32_t end_bitmask = ~((end_bit << 1) - 1);
+
+ // If the start address and end address are the same, we mask that
+ // word once, otherwise mask the starting and ending word
+ // separately and all the ones in between.
+ if (start_word_address == end_word_address) {
+ Memory::uint32_at(start_word_address) &= (start_bitmask | end_bitmask);
+ } else {
+ Memory::uint32_at(start_word_address) &= start_bitmask;
+ Memory::uint32_at(end_word_address) &= end_bitmask;
+ start_word_address += kIntSize;
+ memset(start_word_address, 0, end_word_address - start_word_address);
+ }
+}
+
+
+class UpdateRSetVisitor: public ObjectVisitor {
+ public:
+
+ void VisitPointer(Object** p) {
+ UpdateRSet(p);
+ }
+
+ void VisitPointers(Object** start, Object** end) {
+ // Update a store into slots [start, end), used (a) to update remembered
+ // set when promoting a young object to old space or (b) to rebuild
+ // remembered sets after a mark-compact collection.
+ for (Object** p = start; p < end; p++) UpdateRSet(p);
+ }
+ private:
+
+ void UpdateRSet(Object** p) {
+ // The remembered set should not be set. It should be clear for objects
+ // newly copied to old space, and it is cleared before rebuilding in the
+ // mark-compact collector.
+ ASSERT(!Page::IsRSetSet(reinterpret_cast<Address>(p), 0));
+ if (Heap::InNewSpace(*p)) {
+ Page::SetRSet(reinterpret_cast<Address>(p), 0);
+ }
+ }
+};
+
+
+int Heap::UpdateRSet(HeapObject* obj) {
+ ASSERT(!InNewSpace(obj));
+ // Special handling of fixed arrays to iterate the body based on the start
+ // address and offset. Just iterating the pointers as in UpdateRSetVisitor
+ // will not work because Page::SetRSet needs to have the start of the
+ // object.
+ if (obj->IsFixedArray()) {
+ FixedArray* array = FixedArray::cast(obj);
+ int length = array->length();
+ for (int i = 0; i < length; i++) {
+ int offset = FixedArray::kHeaderSize + i * kPointerSize;
+ ASSERT(!Page::IsRSetSet(obj->address(), offset));
+ if (Heap::InNewSpace(array->get(i))) {
+ Page::SetRSet(obj->address(), offset);
+ }
+ }
+ } else if (!obj->IsCode()) {
+ // Skip code object, we know it does not contain inter-generational
+ // pointers.
+ UpdateRSetVisitor v;
+ obj->Iterate(&v);
+ }
+ return obj->Size();
+}
+
+
+void Heap::RebuildRSets() {
+ // By definition, we do not care about remembered set bits in code space.
+ map_space_->ClearRSet();
+ RebuildRSets(map_space_);
+
+ old_space_->ClearRSet();
+ RebuildRSets(old_space_);
+
+ Heap::lo_space_->ClearRSet();
+ RebuildRSets(lo_space_);
+}
+
+
+void Heap::RebuildRSets(PagedSpace* space) {
+ HeapObjectIterator it(space);
+ while (it.has_next()) Heap::UpdateRSet(it.next());
+}
+
+
+void Heap::RebuildRSets(LargeObjectSpace* space) {
+ LargeObjectIterator it(space);
+ while (it.has_next()) Heap::UpdateRSet(it.next());
+}
+
+
+#if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
+void Heap::RecordCopiedObject(HeapObject* obj) {
+ bool should_record = false;
+#ifdef DEBUG
+ should_record = FLAG_heap_stats;
+#endif
+#ifdef ENABLE_LOGGING_AND_PROFILING
+ should_record = should_record || FLAG_log_gc;
+#endif
+ if (should_record) {
+ if (new_space_->Contains(obj)) {
+ new_space_->RecordAllocation(obj);
+ } else {
+ new_space_->RecordPromotion(obj);
+ }
+ }
+}
+#endif // defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
+
+
+HeapObject* Heap::MigrateObject(HeapObject** source_p,
+ HeapObject* target,
+ int size) {
+ void** src = reinterpret_cast<void**>((*source_p)->address());
+ void** dst = reinterpret_cast<void**>(target->address());
+ int counter = size/kPointerSize - 1;
+ do {
+ *dst++ = *src++;
+ } while (counter-- > 0);
+
+ // Set forwarding pointers, cannot use Map::cast because it asserts
+ // the value type to be Map.
+ (*source_p)->set_map(reinterpret_cast<Map*>(target));
+
+ // Update NewSpace stats if necessary.
+#if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING)
+ RecordCopiedObject(target);
+#endif
+
+ return target;
+}
+
+
+void Heap::CopyObject(HeapObject** p) {
+ ASSERT(InFromSpace(*p));
+
+ HeapObject* object = *p;
+
+ // We use the first word (where the map pointer usually is) of a
+ // HeapObject to record the forwarding pointer. A forwarding pointer can
+ // point to the old space, the code space, or the to space of the new
+ // generation.
+ HeapObject* first_word = object->map();
+
+ // If the first word (where the map pointer is) is not a map pointer, the
+ // object has already been copied. We do not use first_word->IsMap()
+ // because we know that first_word always has the heap object tag.
+ if (first_word->map()->instance_type() != MAP_TYPE) {
+ *p = first_word;
+ return;
+ }
+
+ // Optimization: Bypass ConsString objects where the right-hand side is
+ // Heap::empty_string(). We do not use object->IsConsString because we
+ // already know that object has the heap object tag.
+ InstanceType type = Map::cast(first_word)->instance_type();
+ if (type < FIRST_NONSTRING_TYPE &&
+ String::cast(object)->representation_tag() == kConsStringTag &&
+ ConsString::cast(object)->second() == Heap::empty_string()) {
+ object = HeapObject::cast(ConsString::cast(object)->first());
+ *p = object;
+ // After patching *p we have to repeat the checks that object is in the
+ // active semispace of the young generation and not already copied.
+ if (!InFromSpace(object)) return;
+ first_word = object->map();
+ if (first_word->map()->instance_type() != MAP_TYPE) {
+ *p = first_word;
+ return;
+ }
+ type = Map::cast(first_word)->instance_type();
+ }
+
+ int object_size = object->SizeFromMap(Map::cast(first_word));
+ Object* result;
+ // If the object should be promoted, we try to copy it to old space.
+ if (ShouldBePromoted(object->address(), object_size)) {
+ // Heap numbers and sequential strings are promoted to code space, all
+ // other object types are promoted to old space. We do not use
+ // object->IsHeapNumber() and object->IsSeqString() because we already
+ // know that object has the heap object tag.
+ bool has_pointers =
+ type != HEAP_NUMBER_TYPE &&
+ (type >= FIRST_NONSTRING_TYPE ||
+ String::cast(object)->representation_tag() != kSeqStringTag);
+ if (has_pointers) {
+ result = old_space_->AllocateRaw(object_size);
+ } else {
+ result = code_space_->AllocateRaw(object_size);
+ }
+
+ if (!result->IsFailure()) {
+ *p = MigrateObject(p, HeapObject::cast(result), object_size);
+ if (has_pointers) {
+ // Record the object's address at the top of the to space, to allow
+ // it to be swept by the scavenger.
+ promoted_top -= kPointerSize;
+ Memory::Object_at(promoted_top) = *p;
+ } else {
+#ifdef DEBUG
+ // Objects promoted to the code space should not have pointers to
+ // new space.
+ VerifyCodeSpacePointersVisitor v;
+ (*p)->Iterate(&v);
+#endif
+ }
+ return;
+ }
+ }
+
+ // The object should remain in new space or the old space allocation failed.
+ result = new_space_->AllocateRaw(object_size);
+ // Failed allocation at this point is utterly unexpected.
+ ASSERT(!result->IsFailure());
+ *p = MigrateObject(p, HeapObject::cast(result), object_size);
+}
+
+
+Object* Heap::AllocatePartialMap(InstanceType instance_type,
+ int instance_size) {
+ Object* result = AllocateRawMap(Map::kSize);
+ if (result->IsFailure()) return result;
+
+ // Map::cast cannot be used due to uninitialized map field.
+ reinterpret_cast<Map*>(result)->set_map(meta_map());
+ reinterpret_cast<Map*>(result)->set_instance_type(instance_type);
+ reinterpret_cast<Map*>(result)->set_instance_size(instance_size);
+ reinterpret_cast<Map*>(result)->set_unused_property_fields(0);
+ return result;
+}
+
+
+Object* Heap::AllocateMap(InstanceType instance_type, int instance_size) {
+ Object* result = AllocateRawMap(Map::kSize);
+ if (result->IsFailure()) return result;
+
+ Map* map = reinterpret_cast<Map*>(result);
+ map->set_map(meta_map());
+ map->set_instance_type(instance_type);
+ map->set_prototype(null_value());
+ map->set_constructor(null_value());
+ map->set_instance_size(instance_size);
+ map->set_instance_descriptors(DescriptorArray::cast(empty_fixed_array()));
+ map->set_code_cache(empty_fixed_array());
+ map->set_unused_property_fields(0);
+ map->set_bit_field(0);
+ return map;
+}
+
+
+bool Heap::CreateInitialMaps() {
+ Object* obj = AllocatePartialMap(MAP_TYPE, Map::kSize);
+ if (obj->IsFailure()) return false;
+
+ // Map::cast cannot be used due to uninitialized map field.
+ meta_map_ = reinterpret_cast<Map*>(obj);
+ meta_map()->set_map(meta_map());
+
+ obj = AllocatePartialMap(FIXED_ARRAY_TYPE, Array::kHeaderSize);
+ if (obj->IsFailure()) return false;
+ fixed_array_map_ = Map::cast(obj);
+
+ obj = AllocatePartialMap(ODDBALL_TYPE, Oddball::kSize);
+ if (obj->IsFailure()) return false;
+ oddball_map_ = Map::cast(obj);
+
+ // Allocate the empty array
+ obj = AllocateEmptyFixedArray();
+ if (obj->IsFailure()) return false;
+ empty_fixed_array_ = FixedArray::cast(obj);
+
+ obj = Allocate(oddball_map(), CODE_SPACE);
+ if (obj->IsFailure()) return false;
+ null_value_ = obj;
+
+ // Fix the instance_descriptors for the existing maps.
+ DescriptorArray* empty_descriptors =
+ DescriptorArray::cast(empty_fixed_array());
+
+ meta_map()->set_instance_descriptors(empty_descriptors);
+ meta_map()->set_code_cache(empty_fixed_array());
+
+ fixed_array_map()->set_instance_descriptors(empty_descriptors);
+ fixed_array_map()->set_code_cache(empty_fixed_array());
+
+ oddball_map()->set_instance_descriptors(empty_descriptors);
+ oddball_map()->set_code_cache(empty_fixed_array());
+
+ // Fix prototype object for existing maps.
+ meta_map()->set_prototype(null_value());
+ meta_map()->set_constructor(null_value());
+
+ fixed_array_map()->set_prototype(null_value());
+ fixed_array_map()->set_constructor(null_value());
+ oddball_map()->set_prototype(null_value());
+ oddball_map()->set_constructor(null_value());
+
+ obj = AllocateMap(HEAP_NUMBER_TYPE, HeapNumber::kSize);
+ if (obj->IsFailure()) return false;
+ heap_number_map_ = Map::cast(obj);
+
+ obj = AllocateMap(PROXY_TYPE, Proxy::kSize);
+ if (obj->IsFailure()) return false;
+ proxy_map_ = Map::cast(obj);
+
+#define ALLOCATE_STRING_MAP(type, size, name) \
+ obj = AllocateMap(type, size); \
+ if (obj->IsFailure()) return false; \
+ name##_map_ = Map::cast(obj);
+ STRING_TYPE_LIST(ALLOCATE_STRING_MAP);
+#undef ALLOCATE_STRING_MAP
+
+ obj = AllocateMap(SHORT_STRING_TYPE, TwoByteString::kHeaderSize);
+ if (obj->IsFailure()) return false;
+ undetectable_short_string_map_ = Map::cast(obj);
+ undetectable_short_string_map_->set_is_undetectable();
+
+ obj = AllocateMap(MEDIUM_STRING_TYPE, TwoByteString::kHeaderSize);
+ if (obj->IsFailure()) return false;
+ undetectable_medium_string_map_ = Map::cast(obj);
+ undetectable_medium_string_map_->set_is_undetectable();
+
+ obj = AllocateMap(LONG_STRING_TYPE, TwoByteString::kHeaderSize);
+ if (obj->IsFailure()) return false;
+ undetectable_long_string_map_ = Map::cast(obj);
+ undetectable_long_string_map_->set_is_undetectable();
+
+ obj = AllocateMap(SHORT_ASCII_STRING_TYPE, AsciiString::kHeaderSize);
+ if (obj->IsFailure()) return false;
+ undetectable_short_ascii_string_map_ = Map::cast(obj);
+ undetectable_short_ascii_string_map_->set_is_undetectable();
+
+ obj = AllocateMap(MEDIUM_ASCII_STRING_TYPE, AsciiString::kHeaderSize);
+ if (obj->IsFailure()) return false;
+ undetectable_medium_ascii_string_map_ = Map::cast(obj);
+ undetectable_medium_ascii_string_map_->set_is_undetectable();
+
+ obj = AllocateMap(LONG_ASCII_STRING_TYPE, AsciiString::kHeaderSize);
+ if (obj->IsFailure()) return false;
+ undetectable_long_ascii_string_map_ = Map::cast(obj);
+ undetectable_long_ascii_string_map_->set_is_undetectable();
+
+ obj = AllocateMap(BYTE_ARRAY_TYPE, Array::kHeaderSize);
+ if (obj->IsFailure()) return false;
+ byte_array_map_ = Map::cast(obj);
+
+ obj = AllocateMap(CODE_TYPE, Code::kHeaderSize);
+ if (obj->IsFailure()) return false;
+ code_map_ = Map::cast(obj);
+
+ obj = AllocateMap(FILLER_TYPE, kPointerSize);
+ if (obj->IsFailure()) return false;
+ one_word_filler_map_ = Map::cast(obj);
+
+ obj = AllocateMap(FILLER_TYPE, 2 * kPointerSize);
+ if (obj->IsFailure()) return false;
+ two_word_filler_map_ = Map::cast(obj);
+
+#define ALLOCATE_STRUCT_MAP(NAME, Name, name) \
+ obj = AllocateMap(NAME##_TYPE, Name::kSize); \
+ if (obj->IsFailure()) return false; \
+ name##_map_ = Map::cast(obj);
+ STRUCT_LIST(ALLOCATE_STRUCT_MAP)
+#undef ALLOCATE_STRUCT_MAP
+
+ obj = AllocateMap(FIXED_ARRAY_TYPE, HeapObject::kSize);
+ if (obj->IsFailure()) return false;
+ hash_table_map_ = Map::cast(obj);
+
+ obj = AllocateMap(FIXED_ARRAY_TYPE, HeapObject::kSize);
+ if (obj->IsFailure()) return false;
+ context_map_ = Map::cast(obj);
+
+ obj = AllocateMap(FIXED_ARRAY_TYPE, HeapObject::kSize);
+ if (obj->IsFailure()) return false;
+ global_context_map_ = Map::cast(obj);
+
+ obj = AllocateMap(JS_FUNCTION_TYPE, JSFunction::kSize);
+ if (obj->IsFailure()) return false;
+ boilerplate_function_map_ = Map::cast(obj);
+
+ obj = AllocateMap(SHARED_FUNCTION_INFO_TYPE, SharedFunctionInfo::kSize);
+ if (obj->IsFailure()) return false;
+ shared_function_info_map_ = Map::cast(obj);
+
+ return true;
+}
+
+
+Object* Heap::AllocateHeapNumber(double value, PretenureFlag pretenure) {
+ // Statically ensure that it is safe to allocate heap numbers in paged
+ // spaces.
+ STATIC_ASSERT(HeapNumber::kSize <= Page::kMaxHeapObjectSize);
+ AllocationSpace space = (pretenure == TENURED) ? CODE_SPACE : NEW_SPACE;
+ Object* result = AllocateRaw(HeapNumber::kSize, space);
+ if (result->IsFailure()) return result;
+
+ HeapObject::cast(result)->set_map(heap_number_map());
+ HeapNumber::cast(result)->set_value(value);
+ return result;
+}
+
+
+Object* Heap::AllocateHeapNumber(double value) {
+ // This version of AllocateHeapNumber is optimized for
+ // allocation in new space.
+ STATIC_ASSERT(HeapNumber::kSize <= Page::kMaxHeapObjectSize);
+ ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
+ Object* result = new_space_->AllocateRaw(HeapNumber::kSize);
+ if (result->IsFailure()) return result;
+ HeapObject::cast(result)->set_map(heap_number_map());
+ HeapNumber::cast(result)->set_value(value);
+ return result;
+}
+
+
+Object* Heap::CreateOddball(Map* map,
+ const char* to_string,
+ Object* to_number) {
+ Object* result = Allocate(map, CODE_SPACE);
+ if (result->IsFailure()) return result;
+ return Oddball::cast(result)->Initialize(to_string, to_number);
+}
+
+
+bool Heap::CreateApiObjects() {
+ Object* obj;
+
+ obj = AllocateMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
+ if (obj->IsFailure()) return false;
+ neander_map_ = Map::cast(obj);
+
+ obj = Heap::AllocateJSObjectFromMap(neander_map_);
+ if (obj->IsFailure()) return false;
+ Object* elements = AllocateFixedArray(2);
+ if (elements->IsFailure()) return false;
+ FixedArray::cast(elements)->set(0, Smi::FromInt(0));
+ JSObject::cast(obj)->set_elements(FixedArray::cast(elements));
+ message_listeners_ = JSObject::cast(obj);
+
+ obj = Heap::AllocateJSObjectFromMap(neander_map_);
+ if (obj->IsFailure()) return false;
+ elements = AllocateFixedArray(2);
+ if (elements->IsFailure()) return false;
+ FixedArray::cast(elements)->set(0, Smi::FromInt(0));
+ JSObject::cast(obj)->set_elements(FixedArray::cast(elements));
+ debug_event_listeners_ = JSObject::cast(obj);
+
+ return true;
+}
+
+void Heap::CreateFixedStubs() {
+ // Here we create roots for fixed stubs. They are needed at GC
+ // for cooking and uncooking (check out frames.cc).
+ // The eliminates the need for doing dictionary lookup in the
+ // stub cache for these stubs.
+ HandleScope scope;
+ {
+ CEntryStub stub;
+ c_entry_code_ = *stub.GetCode();
+ }
+ {
+ CEntryDebugBreakStub stub;
+ c_entry_debug_break_code_ = *stub.GetCode();
+ }
+ {
+ JSEntryStub stub;
+ js_entry_code_ = *stub.GetCode();
+ }
+ {
+ JSConstructEntryStub stub;
+ js_construct_entry_code_ = *stub.GetCode();
+ }
+}
+
+
+bool Heap::CreateInitialObjects() {
+ Object* obj;
+
+ // The -0 value must be set before NumberFromDouble works.
+ obj = AllocateHeapNumber(-0.0, TENURED);
+ if (obj->IsFailure()) return false;
+ minus_zero_value_ = obj;
+ ASSERT(signbit(minus_zero_value_->Number()) != 0);
+
+ obj = AllocateHeapNumber(OS::nan_value(), TENURED);
+ if (obj->IsFailure()) return false;
+ nan_value_ = obj;
+
+ obj = NumberFromDouble(INFINITY, TENURED);
+ if (obj->IsFailure()) return false;
+ infinity_value_ = obj;
+
+ obj = NumberFromDouble(-INFINITY, TENURED);
+ if (obj->IsFailure()) return false;
+ negative_infinity_value_ = obj;
+
+ obj = NumberFromDouble(DBL_MAX, TENURED);
+ if (obj->IsFailure()) return false;
+ number_max_value_ = obj;
+
+ // C++ doesn't provide a constant for the smallest denormalized
+ // double (approx. 5e-324) but only the smallest normalized one
+ // which is somewhat bigger (approx. 2e-308). So we have to do
+ // this raw conversion hack.
+ uint64_t min_value_bits = 1L;
+ double min_value = *reinterpret_cast<double*>(&min_value_bits);
+ obj = NumberFromDouble(min_value, TENURED);
+ if (obj->IsFailure()) return false;
+ number_min_value_ = obj;
+
+ obj = Allocate(oddball_map(), CODE_SPACE);
+ if (obj->IsFailure()) return false;
+ undefined_value_ = obj;
+ ASSERT(!InNewSpace(undefined_value()));
+
+ // Allocate initial symbol table.
+ obj = SymbolTable::Allocate(kInitialSymbolTableSize);
+ if (obj->IsFailure()) return false;
+ symbol_table_ = obj;
+
+ // Assign the print strings for oddballs after creating symboltable.
+ Object* symbol = LookupAsciiSymbol("undefined");
+ if (symbol->IsFailure()) return false;
+ Oddball::cast(undefined_value_)->set_to_string(String::cast(symbol));
+ Oddball::cast(undefined_value_)->set_to_number(nan_value_);
+
+ // Assign the print strings for oddballs after creating symboltable.
+ symbol = LookupAsciiSymbol("null");
+ if (symbol->IsFailure()) return false;
+ Oddball::cast(null_value_)->set_to_string(String::cast(symbol));
+ Oddball::cast(null_value_)->set_to_number(Smi::FromInt(0));
+
+ // Allocate the null_value
+ obj = Oddball::cast(null_value())->Initialize("null", Smi::FromInt(0));
+ if (obj->IsFailure()) return false;
+
+ obj = CreateOddball(oddball_map(), "true", Smi::FromInt(1));
+ if (obj->IsFailure()) return false;
+ true_value_ = obj;
+
+ obj = CreateOddball(oddball_map(), "false", Smi::FromInt(0));
+ if (obj->IsFailure()) return false;
+ false_value_ = obj;
+
+ obj = CreateOddball(oddball_map(), "hole", Smi::FromInt(-1));
+ if (obj->IsFailure()) return false;
+ the_hole_value_ = obj;
+
+ // Allocate the empty string.
+ obj = AllocateRawAsciiString(0, TENURED);
+ if (obj->IsFailure()) return false;
+ empty_string_ = String::cast(obj);
+
+#define SYMBOL_INITIALIZE(name, string) \
+ obj = LookupAsciiSymbol(string); \
+ if (obj->IsFailure()) return false; \
+ (name##_) = String::cast(obj);
+ SYMBOL_LIST(SYMBOL_INITIALIZE)
+#undef SYMBOL_INITIALIZE
+
+ // Allocate the proxy for __proto__.
+ obj = AllocateProxy((Address) &Accessors::ObjectPrototype);
+ if (obj->IsFailure()) return false;
+ prototype_accessors_ = Proxy::cast(obj);
+
+ // Allocate the code_stubs dictionary.
+ obj = Dictionary::Allocate(4);
+ if (obj->IsFailure()) return false;
+ code_stubs_ = Dictionary::cast(obj);
+
+ // Allocate the non_monomorphic_cache used in stub-cache.cc
+ obj = Dictionary::Allocate(4);
+ if (obj->IsFailure()) return false;
+ non_monomorphic_cache_ = Dictionary::cast(obj);
+
+ CreateFixedStubs();
+
+ // Allocate the number->string conversion cache
+ obj = AllocateFixedArray(kNumberStringCacheSize * 2);
+ if (obj->IsFailure()) return false;
+ number_string_cache_ = FixedArray::cast(obj);
+
+ // Allocate cache for single character strings.
+ obj = AllocateFixedArray(String::kMaxAsciiCharCode+1);
+ if (obj->IsFailure()) return false;
+ single_character_string_cache_ = FixedArray::cast(obj);
+
+ // Allocate cache for external strings pointing to native source code.
+ obj = AllocateFixedArray(Natives::GetBuiltinsCount());
+ if (obj->IsFailure()) return false;
+ natives_source_cache_ = FixedArray::cast(obj);
+
+ return true;
+}
+
+
+static inline int double_get_hash(double d) {
+ DoubleRepresentation rep(d);
+ return ((static_cast<int>(rep.bits) ^ static_cast<int>(rep.bits >> 32)) &
+ (Heap::kNumberStringCacheSize - 1));
+}
+
+
+static inline int smi_get_hash(Smi* smi) {
+ return (smi->value() & (Heap::kNumberStringCacheSize - 1));
+}
+
+
+
+Object* Heap::GetNumberStringCache(Object* number) {
+ int hash;
+ if (number->IsSmi()) {
+ hash = smi_get_hash(Smi::cast(number));
+ } else {
+ hash = double_get_hash(number->Number());
+ }
+ Object* key = number_string_cache_->get(hash * 2);
+ if (key == number) {
+ return String::cast(number_string_cache_->get(hash * 2 + 1));
+ } else if (key->IsHeapNumber() &&
+ number->IsHeapNumber() &&
+ key->Number() == number->Number()) {
+ return String::cast(number_string_cache_->get(hash * 2 + 1));
+ }
+ return undefined_value();
+}
+
+
+void Heap::SetNumberStringCache(Object* number, String* string) {
+ int hash;
+ if (number->IsSmi()) {
+ hash = smi_get_hash(Smi::cast(number));
+ number_string_cache_->set(hash * 2, number, FixedArray::SKIP_WRITE_BARRIER);
+ } else {
+ hash = double_get_hash(number->Number());
+ number_string_cache_->set(hash * 2, number);
+ }
+ number_string_cache_->set(hash * 2 + 1, string);
+}
+
+
+Object* Heap::SmiOrNumberFromDouble(double value,
+ bool new_object,
+ PretenureFlag pretenure) {
+ // We need to distinguish the minus zero value and this cannot be
+ // done after conversion to int. Doing this by comparing bit
+ // patterns is faster than using fpclassify() et al.
+ static const DoubleRepresentation plus_zero(0.0);
+ static const DoubleRepresentation minus_zero(-0.0);
+ static const DoubleRepresentation nan(OS::nan_value());
+ ASSERT(minus_zero_value_ != NULL);
+ ASSERT(sizeof(plus_zero.value) == sizeof(plus_zero.bits));
+
+ DoubleRepresentation rep(value);
+ if (rep.bits == plus_zero.bits) return Smi::FromInt(0); // not uncommon
+ if (rep.bits == minus_zero.bits) {
+ return new_object ? AllocateHeapNumber(-0.0, pretenure)
+ : minus_zero_value_;
+ }
+ if (rep.bits == nan.bits) {
+ return new_object
+ ? AllocateHeapNumber(OS::nan_value(), pretenure)
+ : nan_value_;
+ }
+
+ // Try to represent the value as a tagged small integer.
+ int int_value = FastD2I(value);
+ if (value == FastI2D(int_value) && Smi::IsValid(int_value)) {
+ return Smi::FromInt(int_value);
+ }
+
+ // Materialize the value in the heap.
+ return AllocateHeapNumber(value, pretenure);
+}
+
+
+Object* Heap::NewNumberFromDouble(double value, PretenureFlag pretenure) {
+ return SmiOrNumberFromDouble(value,
+ true /* number object must be new */,
+ pretenure);
+}
+
+
+Object* Heap::NumberFromDouble(double value, PretenureFlag pretenure) {
+ return SmiOrNumberFromDouble(value,
+ false /* use preallocated NaN, -0.0 */,
+ pretenure);
+}
+
+
+Object* Heap::AllocateProxy(Address proxy, PretenureFlag pretenure) {
+ // Statically ensure that it is safe to allocate proxies in paged spaces.
+ STATIC_ASSERT(Proxy::kSize <= Page::kMaxHeapObjectSize);
+ AllocationSpace space = (pretenure == TENURED) ? OLD_SPACE : NEW_SPACE;
+ Object* result = Allocate(proxy_map(), space);
+ if (result->IsFailure()) return result;
+
+ Proxy::cast(result)->set_proxy(proxy);
+ return result;
+}
+
+
+Object* Heap::AllocateSharedFunctionInfo(Object* name) {
+ Object* result = Allocate(shared_function_info_map(), NEW_SPACE);
+ if (result->IsFailure()) return result;
+
+ SharedFunctionInfo* share = SharedFunctionInfo::cast(result);
+ share->set_name(name);
+ Code* illegal = Builtins::builtin(Builtins::Illegal);
+ share->set_code(illegal);
+ share->set_expected_nof_properties(0);
+ share->set_length(0);
+ share->set_formal_parameter_count(0);
+ share->set_instance_class_name(Object_symbol());
+ share->set_function_data(undefined_value());
+ share->set_lazy_load_data(undefined_value());
+ share->set_script(undefined_value());
+ share->set_start_position_and_type(0);
+ share->set_debug_info(undefined_value());
+ return result;
+}
+
+
+Object* Heap::AllocateConsString(String* first, String* second) {
+ int length = first->length() + second->length();
+ bool is_ascii = first->is_ascii() && second->is_ascii();
+
+ // If the resulting string is small make a flat string.
+ if (length < ConsString::kMinLength) {
+ Object* result = is_ascii
+ ? AllocateRawAsciiString(length)
+ : AllocateRawTwoByteString(length);
+ if (result->IsFailure()) return result;
+ // Copy the characters into the new object.
+ String* string_result = String::cast(result);
+ int first_length = first->length();
+ // Copy the content of the first string.
+ for (int i = 0; i < first_length; i++) {
+ string_result->Set(i, first->Get(i));
+ }
+ int second_length = second->length();
+ // Copy the content of the first string.
+ for (int i = 0; i < second_length; i++) {
+ string_result->Set(first_length + i, second->Get(i));
+ }
+ return result;
+ }
+
+ Map* map;
+ if (length <= String::kMaxShortStringSize) {
+ map = is_ascii ? short_cons_ascii_string_map()
+ : short_cons_string_map();
+ } else if (length <= String::kMaxMediumStringSize) {
+ map = is_ascii ? medium_cons_ascii_string_map()
+ : medium_cons_string_map();
+ } else {
+ map = is_ascii ? long_cons_ascii_string_map()
+ : long_cons_string_map();
+ }
+
+ Object* result = Allocate(map, NEW_SPACE);
+ if (result->IsFailure()) return result;
+
+ ConsString* cons_string = ConsString::cast(result);
+ cons_string->set_first(first);
+ cons_string->set_second(second);
+ cons_string->set_length(length);
+
+ return result;
+}
+
+
+Object* Heap::AllocateSlicedString(String* buffer, int start, int end) {
+ int length = end - start;
+
+ // If the resulting string is small make a sub string.
+ if (end - start <= SlicedString::kMinLength) {
+ return Heap::AllocateSubString(buffer, start, end);
+ }
+
+ Map* map;
+ if (length <= String::kMaxShortStringSize) {
+ map = buffer->is_ascii() ? short_sliced_ascii_string_map()
+ : short_sliced_string_map();
+ } else if (length <= String::kMaxMediumStringSize) {
+ map = buffer->is_ascii() ? medium_sliced_ascii_string_map()
+ : medium_sliced_string_map();
+ } else {
+ map = buffer->is_ascii() ? long_sliced_ascii_string_map()
+ : long_sliced_string_map();
+ }
+
+ Object* result = Allocate(map, NEW_SPACE);
+ if (result->IsFailure()) return result;
+
+ SlicedString* sliced_string = SlicedString::cast(result);
+ sliced_string->set_buffer(buffer);
+ sliced_string->set_start(start);
+ sliced_string->set_length(length);
+
+ return result;
+}
+
+
+Object* Heap::AllocateSubString(String* buffer, int start, int end) {
+ int length = end - start;
+
+ // Make an attempt to flatten the buffer to reduce access time.
+ buffer->TryFlatten();
+
+ Object* result = buffer->is_ascii()
+ ? AllocateRawAsciiString(length)
+ : AllocateRawTwoByteString(length);
+ if (result->IsFailure()) return result;
+
+ // Copy the characters into the new object.
+ String* string_result = String::cast(result);
+ for (int i = 0; i < length; i++) {
+ string_result->Set(i, buffer->Get(start + i));
+ }
+ return result;
+}
+
+
+Object* Heap::AllocateExternalStringFromAscii(
+ ExternalAsciiString::Resource* resource) {
+ Map* map;
+ int length = resource->length();
+ if (length <= String::kMaxShortStringSize) {
+ map = short_external_ascii_string_map();
+ } else if (length <= String::kMaxMediumStringSize) {
+ map = medium_external_ascii_string_map();
+ } else {
+ map = long_external_ascii_string_map();
+ }
+
+ Object* result = Allocate(map, NEW_SPACE);
+ if (result->IsFailure()) return result;
+
+ ExternalAsciiString* external_string = ExternalAsciiString::cast(result);
+ external_string->set_length(length);
+ external_string->set_resource(resource);
+
+ return result;
+}
+
+
+Object* Heap::AllocateExternalStringFromTwoByte(
+ ExternalTwoByteString::Resource* resource) {
+ Map* map;
+ int length = resource->length();
+ if (length <= String::kMaxShortStringSize) {
+ map = short_external_string_map();
+ } else if (length <= String::kMaxMediumStringSize) {
+ map = medium_external_string_map();
+ } else {
+ map = long_external_string_map();
+ }
+
+ Object* result = Allocate(map, NEW_SPACE);
+ if (result->IsFailure()) return result;
+
+ ExternalTwoByteString* external_string = ExternalTwoByteString::cast(result);
+ external_string->set_length(length);
+ external_string->set_resource(resource);
+
+ return result;
+}
+
+
+Object* Heap:: LookupSingleCharacterStringFromCode(uint16_t code) {
+ if (code <= String::kMaxAsciiCharCode) {
+ Object* value = Heap::single_character_string_cache()->get(code);
+ if (value != Heap::undefined_value()) return value;
+ Object* result = Heap::AllocateRawAsciiString(1);
+ if (result->IsFailure()) return result;
+ String::cast(result)->Set(0, code);
+ Heap::single_character_string_cache()->set(code, result);
+ return result;
+ }
+ Object* result = Heap::AllocateRawTwoByteString(1);
+ if (result->IsFailure()) return result;
+ String::cast(result)->Set(0, code);
+ return result;
+}
+
+
+Object* Heap::AllocateByteArray(int length) {
+ int size = ByteArray::SizeFor(length);
+ AllocationSpace space = size > MaxHeapObjectSize() ? LO_SPACE : NEW_SPACE;
+
+ Object* result = AllocateRaw(size, space);
+ if (result->IsFailure()) return result;
+
+ reinterpret_cast<Array*>(result)->set_map(byte_array_map());
+ reinterpret_cast<Array*>(result)->set_length(length);
+ return result;
+}
+
+
+Object* Heap::CreateCode(const CodeDesc& desc,
+ ScopeInfo<>* sinfo,
+ Code::Flags flags) {
+ // Compute size
+ int body_size = RoundUp(desc.instr_size + desc.reloc_size, kObjectAlignment);
+ int sinfo_size = 0;
+ if (sinfo != NULL) sinfo_size = sinfo->Serialize(NULL);
+ int obj_size = Code::SizeFor(body_size, sinfo_size);
+ AllocationSpace space =
+ (obj_size > MaxHeapObjectSize()) ? LO_SPACE : CODE_SPACE;
+
+ Object* result = AllocateRaw(obj_size, space);
+ if (result->IsFailure()) return result;
+
+ // Initialize the object
+ HeapObject::cast(result)->set_map(code_map());
+ Code* code = Code::cast(result);
+ code->set_instruction_size(desc.instr_size);
+ code->set_relocation_size(desc.reloc_size);
+ code->set_sinfo_size(sinfo_size);
+ code->set_flags(flags);
+ code->set_ic_flag(Code::IC_TARGET_IS_ADDRESS);
+ code->CopyFrom(desc); // migrate generated code
+ if (sinfo != NULL) sinfo->Serialize(code); // write scope info
+
+#ifdef DEBUG
+ code->Verify();
+#endif
+
+ CPU::FlushICache(code->instruction_start(), code->instruction_size());
+
+ return code;
+}
+
+
+Object* Heap::CopyCode(Code* code) {
+ // Allocate an object the same size as the code object.
+ int obj_size = code->Size();
+ AllocationSpace space =
+ (obj_size > MaxHeapObjectSize()) ? LO_SPACE : CODE_SPACE;
+ Object* result = AllocateRaw(obj_size, space);
+ if (result->IsFailure()) return result;
+
+ // Copy code object.
+ Address old_addr = code->address();
+ Address new_addr = reinterpret_cast<HeapObject*>(result)->address();
+ memcpy(new_addr, old_addr, obj_size);
+
+ // Relocate the copy.
+ Code* new_code = Code::cast(result);
+ new_code->Relocate(new_addr - old_addr);
+
+ CPU::FlushICache(new_code->instruction_start(), new_code->instruction_size());
+
+ return new_code;
+}
+
+
+Object* Heap::Allocate(Map* map, AllocationSpace space) {
+ ASSERT(gc_state_ == NOT_IN_GC);
+ ASSERT(map->instance_type() != MAP_TYPE);
+ Object* result = AllocateRaw(map->instance_size(), space);
+ if (result->IsFailure()) return result;
+ HeapObject::cast(result)->set_map(map);
+ return result;
+}
+
+
+Object* Heap::InitializeFunction(JSFunction* function,
+ SharedFunctionInfo* shared,
+ Object* prototype) {
+ ASSERT(!prototype->IsMap());
+ function->initialize_properties();
+ function->initialize_elements();
+ function->set_shared(shared);
+ function->set_prototype_or_initial_map(prototype);
+ function->set_context(undefined_value());
+ function->set_literals(empty_fixed_array());
+ return function;
+}
+
+
+Object* Heap::AllocateFunctionPrototype(JSFunction* function) {
+ // Allocate the prototype.
+ Object* prototype =
+ AllocateJSObject(Top::context()->global_context()->object_function());
+ if (prototype->IsFailure()) return prototype;
+ // When creating the prototype for the function we must set its
+ // constructor to the function.
+ Object* result =
+ JSObject::cast(prototype)->SetProperty(constructor_symbol(),
+ function,
+ DONT_ENUM);
+ if (result->IsFailure()) return result;
+ return prototype;
+}
+
+
+Object* Heap::AllocateFunction(Map* function_map,
+ SharedFunctionInfo* shared,
+ Object* prototype) {
+ Object* result = Allocate(function_map, OLD_SPACE);
+ if (result->IsFailure()) return result;
+ return InitializeFunction(JSFunction::cast(result), shared, prototype);
+}
+
+
+Object* Heap::AllocateArgumentsObject(Object* callee, int length) {
+ // This allocation is odd since allocate an argument object
+ // based on the arguments_boilerplate.
+ // We do this to ensure fast allocation and map sharing.
+
+ // This calls Copy directly rather than using Heap::AllocateRaw so we
+ // duplicate the check here.
+ ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
+
+ JSObject* boilerplate =
+ Top::context()->global_context()->arguments_boilerplate();
+ Object* result = boilerplate->Copy();
+ if (result->IsFailure()) return result;
+
+ Object* obj = JSObject::cast(result)->properties();
+ FixedArray::cast(obj)->set(arguments_callee_index, callee);
+ FixedArray::cast(obj)->set(arguments_length_index, Smi::FromInt(length));
+
+ // Allocate the fixed array.
+ obj = Heap::AllocateFixedArray(length);
+ if (obj->IsFailure()) return obj;
+ JSObject::cast(result)->set_elements(FixedArray::cast(obj));
+
+ // Check the state of the object
+ ASSERT(JSObject::cast(result)->HasFastProperties());
+ ASSERT(JSObject::cast(result)->HasFastElements());
+
+ return result;
+}
+
+
+Object* Heap::AllocateInitialMap(JSFunction* fun) {
+ ASSERT(!fun->has_initial_map());
+
+ // First create a new map.
+ Object* map_obj = Heap::AllocateMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
+ if (map_obj->IsFailure()) return map_obj;
+
+ // Fetch or allocate prototype.
+ Object* prototype;
+ if (fun->has_instance_prototype()) {
+ prototype = fun->instance_prototype();
+ } else {
+ prototype = AllocateFunctionPrototype(fun);
+ if (prototype->IsFailure()) return prototype;
+ }
+ Map* map = Map::cast(map_obj);
+ map->set_unused_property_fields(fun->shared()->expected_nof_properties());
+ map->set_prototype(prototype);
+ return map;
+}
+
+
+void Heap::InitializeJSObjectFromMap(JSObject* obj,
+ FixedArray* properties,
+ Map* map) {
+ obj->set_properties(properties);
+ obj->initialize_elements();
+ // TODO(1240798): Initialize the object's body using valid initial values
+ // according to the object's initial map. For example, if the map's
+ // instance type is JS_ARRAY_TYPE, the length field should be initialized
+ // to a number (eg, Smi::FromInt(0)) and the elements initialized to a
+ // fixed array (eg, Heap::empty_fixed_array()). Currently, the object
+ // verification code has to cope with (temporarily) invalid objects. See
+ // for example, JSArray::JSArrayVerify).
+ obj->InitializeBody(map->instance_size());
+}
+
+
+Object* Heap::AllocateJSObjectFromMap(Map* map, PretenureFlag pretenure) {
+ // JSFunctions should be allocated using AllocateFunction to be
+ // properly initialized.
+ ASSERT(map->instance_type() != JS_FUNCTION_TYPE);
+
+ // Allocate the backing storage for the properties.
+ Object* properties = AllocatePropertyStorageForMap(map);
+ if (properties->IsFailure()) return properties;
+
+ // Allocate the JSObject.
+ AllocationSpace space = (pretenure == TENURED) ? OLD_SPACE : NEW_SPACE;
+ if (map->instance_size() > MaxHeapObjectSize()) space = LO_SPACE;
+ Object* obj = Allocate(map, space);
+ if (obj->IsFailure()) return obj;
+
+ // Initialize the JSObject.
+ InitializeJSObjectFromMap(JSObject::cast(obj),
+ FixedArray::cast(properties),
+ map);
+ return obj;
+}
+
+
+Object* Heap::AllocateJSObject(JSFunction* constructor,
+ PretenureFlag pretenure) {
+ // Allocate the initial map if absent.
+ if (!constructor->has_initial_map()) {
+ Object* initial_map = AllocateInitialMap(constructor);
+ if (initial_map->IsFailure()) return initial_map;
+ constructor->set_initial_map(Map::cast(initial_map));
+ Map::cast(initial_map)->set_constructor(constructor);
+ }
+ // Allocate the object based on the constructors initial map.
+ return AllocateJSObjectFromMap(constructor->initial_map(), pretenure);
+}
+
+
+Object* Heap::ReinitializeJSGlobalObject(JSFunction* constructor,
+ JSGlobalObject* object) {
+ // Allocate initial map if absent.
+ if (!constructor->has_initial_map()) {
+ Object* initial_map = AllocateInitialMap(constructor);
+ if (initial_map->IsFailure()) return initial_map;
+ constructor->set_initial_map(Map::cast(initial_map));
+ Map::cast(initial_map)->set_constructor(constructor);
+ }
+
+ Map* map = constructor->initial_map();
+
+ // Check that the already allocated object has the same size as
+ // objects allocated using the constructor.
+ ASSERT(map->instance_size() == object->map()->instance_size());
+
+ // Allocate the backing storage for the properties.
+ Object* properties = AllocatePropertyStorageForMap(map);
+ if (properties->IsFailure()) return properties;
+
+ // Reset the map for the object.
+ object->set_map(constructor->initial_map());
+
+ // Reinitialize the object from the constructor map.
+ InitializeJSObjectFromMap(object, FixedArray::cast(properties), map);
+ return object;
+}
+
+
+Object* Heap::AllocateStringFromAscii(Vector<const char> string,
+ PretenureFlag pretenure) {
+ Object* result = AllocateRawAsciiString(string.length(), pretenure);
+ if (result->IsFailure()) return result;
+
+ // Copy the characters into the new object.
+ AsciiString* string_result = AsciiString::cast(result);
+ for (int i = 0; i < string.length(); i++) {
+ string_result->AsciiStringSet(i, string[i]);
+ }
+ return result;
+}
+
+
+Object* Heap::AllocateStringFromUtf8(Vector<const char> string,
+ PretenureFlag pretenure) {
+ // Count the number of characters in the UTF-8 string and check if
+ // it is an ASCII string.
+ Access<Scanner::Utf8Decoder> decoder(Scanner::utf8_decoder());
+ decoder->Reset(string.start(), string.length());
+ int chars = 0;
+ bool is_ascii = true;
+ while (decoder->has_more()) {
+ uc32 r = decoder->GetNext();
+ if (r > String::kMaxAsciiCharCode) is_ascii = false;
+ chars++;
+ }
+
+ // If the string is ascii, we do not need to convert the characters
+ // since UTF8 is backwards compatible with ascii.
+ if (is_ascii) return AllocateStringFromAscii(string, pretenure);
+
+ Object* result = AllocateRawTwoByteString(chars, pretenure);
+ if (result->IsFailure()) return result;
+
+ // Convert and copy the characters into the new object.
+ String* string_result = String::cast(result);
+ decoder->Reset(string.start(), string.length());
+ for (int i = 0; i < chars; i++) {
+ uc32 r = decoder->GetNext();
+ string_result->Set(i, r);
+ }
+ return result;
+}
+
+
+Object* Heap::AllocateStringFromTwoByte(Vector<const uc16> string,
+ PretenureFlag pretenure) {
+ // Check if the string is an ASCII string.
+ int i = 0;
+ while (i < string.length() && string[i] <= String::kMaxAsciiCharCode) i++;
+
+ Object* result;
+ if (i == string.length()) { // It's an ASCII string.
+ result = AllocateRawAsciiString(string.length(), pretenure);
+ } else { // It's not an ASCII string.
+ result = AllocateRawTwoByteString(string.length(), pretenure);
+ }
+ if (result->IsFailure()) return result;
+
+ // Copy the characters into the new object, which may be either ASCII or
+ // UTF-16.
+ String* string_result = String::cast(result);
+ for (int i = 0; i < string.length(); i++) {
+ string_result->Set(i, string[i]);
+ }
+ return result;
+}
+
+
+Map* Heap::SymbolMapForString(String* string) {
+ // If the string is in new space it cannot be used as a symbol.
+ if (InNewSpace(string)) return NULL;
+
+ // Find the corresponding symbol map for strings.
+ Map* map = string->map();
+
+ if (map == short_ascii_string_map()) return short_ascii_symbol_map();
+ if (map == medium_ascii_string_map()) return medium_ascii_symbol_map();
+ if (map == long_ascii_string_map()) return long_ascii_symbol_map();
+
+ if (map == short_string_map()) return short_symbol_map();
+ if (map == medium_string_map()) return medium_symbol_map();
+ if (map == long_string_map()) return long_symbol_map();
+
+ if (map == short_cons_string_map()) return short_cons_symbol_map();
+ if (map == medium_cons_string_map()) return medium_cons_symbol_map();
+ if (map == long_cons_string_map()) return long_cons_symbol_map();
+
+ if (map == short_cons_ascii_string_map()) {
+ return short_cons_ascii_symbol_map();
+ }
+ if (map == medium_cons_ascii_string_map()) {
+ return medium_cons_ascii_symbol_map();
+ }
+ if (map == long_cons_ascii_string_map()) {
+ return long_cons_ascii_symbol_map();
+ }
+
+ if (map == short_sliced_string_map()) return short_sliced_symbol_map();
+ if (map == medium_sliced_string_map()) return short_sliced_symbol_map();
+ if (map == long_sliced_string_map()) return short_sliced_symbol_map();
+
+ if (map == short_sliced_ascii_string_map()) {
+ return short_sliced_ascii_symbol_map();
+ }
+ if (map == medium_sliced_ascii_string_map()) {
+ return short_sliced_ascii_symbol_map();
+ }
+ if (map == long_sliced_ascii_string_map()) {
+ return short_sliced_ascii_symbol_map();
+ }
+
+ if (map == short_external_string_map()) return short_external_string_map();
+ if (map == medium_external_string_map()) return medium_external_string_map();
+ if (map == long_external_string_map()) return long_external_string_map();
+
+ if (map == short_external_ascii_string_map()) {
+ return short_external_ascii_string_map();
+ }
+ if (map == medium_external_ascii_string_map()) {
+ return medium_external_ascii_string_map();
+ }
+ if (map == long_external_ascii_string_map()) {
+ return long_external_ascii_string_map();
+ }
+
+ // No match found.
+ return NULL;
+}
+
+
+Object* Heap::AllocateSymbol(unibrow::CharacterStream* buffer,
+ int chars,
+ int hash) {
+ // Ensure the chars matches the number of characters in the buffer.
+ ASSERT(static_cast<unsigned>(chars) == buffer->Length());
+ // Determine whether the string is ascii.
+ bool is_ascii = true;
+ while (buffer->has_more()) {
+ if (buffer->GetNext() > unibrow::Utf8::kMaxOneByteChar) is_ascii = false;
+ }
+ buffer->Rewind();
+
+ // Compute map and object size.
+ int size;
+ Map* map;
+
+ if (is_ascii) {
+ if (chars <= String::kMaxShortStringSize) {
+ map = short_ascii_symbol_map();
+ } else if (chars <= String::kMaxMediumStringSize) {
+ map = medium_ascii_symbol_map();
+ } else {
+ map = long_ascii_symbol_map();
+ }
+ size = AsciiString::SizeFor(chars);
+ } else {
+ if (chars <= String::kMaxShortStringSize) {
+ map = short_symbol_map();
+ } else if (chars <= String::kMaxMediumStringSize) {
+ map = medium_symbol_map();
+ } else {
+ map = long_symbol_map();
+ }
+ size = TwoByteString::SizeFor(chars);
+ }
+
+ // Allocate string.
+ AllocationSpace space = (size > MaxHeapObjectSize()) ? LO_SPACE : CODE_SPACE;
+ Object* result = AllocateRaw(size, space);
+ if (result->IsFailure()) return result;
+
+ reinterpret_cast<HeapObject*>(result)->set_map(map);
+ // The hash value contains the length of the string.
+ String::cast(result)->set_length_field(hash);
+
+ ASSERT_EQ(size, String::cast(result)->Size());
+
+ // Fill in the characters.
+ for (int i = 0; i < chars; i++) {
+ String::cast(result)->Set(i, buffer->GetNext());
+ }
+ return result;
+}
+
+
+Object* Heap::AllocateRawAsciiString(int length, PretenureFlag pretenure) {
+ AllocationSpace space = (pretenure == TENURED) ? CODE_SPACE : NEW_SPACE;
+ int size = AsciiString::SizeFor(length);
+ if (size > MaxHeapObjectSize()) {
+ space = LO_SPACE;
+ }
+
+ // Use AllocateRaw rather than Allocate because the object's size cannot be
+ // determined from the map.
+ Object* result = AllocateRaw(size, space);
+ if (result->IsFailure()) return result;
+
+ // Determine the map based on the string's length.
+ Map* map;
+ if (length <= String::kMaxShortStringSize) {
+ map = short_ascii_string_map();
+ } else if (length <= String::kMaxMediumStringSize) {
+ map = medium_ascii_string_map();
+ } else {
+ map = long_ascii_string_map();
+ }
+
+ // Partially initialize the object.
+ HeapObject::cast(result)->set_map(map);
+ String::cast(result)->set_length(length);
+ ASSERT_EQ(size, HeapObject::cast(result)->Size());
+ return result;
+}
+
+
+Object* Heap::AllocateRawTwoByteString(int length, PretenureFlag pretenure) {
+ AllocationSpace space = (pretenure == TENURED) ? CODE_SPACE : NEW_SPACE;
+ int size = TwoByteString::SizeFor(length);
+ if (size > MaxHeapObjectSize()) {
+ space = LO_SPACE;
+ }
+
+ // Use AllocateRaw rather than Allocate because the object's size cannot be
+ // determined from the map.
+ Object* result = AllocateRaw(size, space);
+ if (result->IsFailure()) return result;
+
+ // Determine the map based on the string's length.
+ Map* map;
+ if (length <= String::kMaxShortStringSize) {
+ map = short_string_map();
+ } else if (length <= String::kMaxMediumStringSize) {
+ map = medium_string_map();
+ } else {
+ map = long_string_map();
+ }
+
+ // Partially initialize the object.
+ HeapObject::cast(result)->set_map(map);
+ String::cast(result)->set_length(length);
+ ASSERT_EQ(size, HeapObject::cast(result)->Size());
+ return result;
+}
+
+
+Object* Heap::AllocateEmptyFixedArray() {
+ int size = FixedArray::SizeFor(0);
+ Object* result = AllocateRaw(size, CODE_SPACE);
+ if (result->IsFailure()) return result;
+ // Initialize the object.
+ reinterpret_cast<Array*>(result)->set_map(fixed_array_map());
+ reinterpret_cast<Array*>(result)->set_length(0);
+ return result;
+}
+
+
+Object* Heap::AllocateFixedArray(int length, PretenureFlag pretenure) {
+ ASSERT(empty_fixed_array()->IsFixedArray());
+ if (length == 0) return empty_fixed_array();
+
+ int size = FixedArray::SizeFor(length);
+ Object* result;
+ if (size > MaxHeapObjectSize()) {
+ result = lo_space_->AllocateRawFixedArray(size);
+ } else {
+ AllocationSpace space = (pretenure == TENURED) ? OLD_SPACE : NEW_SPACE;
+ result = AllocateRaw(size, space);
+ }
+ if (result->IsFailure()) return result;
+
+ // Initialize the object.
+ reinterpret_cast<Array*>(result)->set_map(fixed_array_map());
+ FixedArray* array = FixedArray::cast(result);
+ array->set_length(length);
+ for (int index = 0; index < length; index++) array->set_undefined(index);
+ return array;
+}
+
+
+Object* Heap::AllocateFixedArrayWithHoles(int length) {
+ if (length == 0) return empty_fixed_array();
+ int size = FixedArray::SizeFor(length);
+ Object* result = size > MaxHeapObjectSize()
+ ? lo_space_->AllocateRawFixedArray(size)
+ : AllocateRaw(size, NEW_SPACE);
+ if (result->IsFailure()) return result;
+
+ // Initialize the object.
+ reinterpret_cast<Array*>(result)->set_map(fixed_array_map());
+ FixedArray* array = FixedArray::cast(result);
+ array->set_length(length);
+ for (int index = 0; index < length; index++) array->set_the_hole(index);
+ return array;
+}
+
+
+Object* Heap::AllocateHashTable(int length) {
+ Object* result = Heap::AllocateFixedArray(length);
+ if (result->IsFailure()) return result;
+ reinterpret_cast<Array*>(result)->set_map(hash_table_map());
+ ASSERT(result->IsDictionary());
+ return result;
+}
+
+
+Object* Heap::AllocateGlobalContext() {
+ Object* result = Heap::AllocateFixedArray(Context::GLOBAL_CONTEXT_SLOTS);
+ if (result->IsFailure()) return result;
+ Context* context = reinterpret_cast<Context*>(result);
+ context->set_map(global_context_map());
+ ASSERT(context->IsGlobalContext());
+ ASSERT(result->IsContext());
+ return result;
+}
+
+
+Object* Heap::AllocateFunctionContext(int length, JSFunction* function) {
+ ASSERT(length >= Context::MIN_CONTEXT_SLOTS);
+ Object* result = Heap::AllocateFixedArray(length);
+ if (result->IsFailure()) return result;
+ Context* context = reinterpret_cast<Context*>(result);
+ context->set_map(context_map());
+ context->set_closure(function);
+ context->set_fcontext(context);
+ context->set_previous(NULL);
+ context->set_extension(NULL);
+ context->set_global(function->context()->global());
+ ASSERT(!context->IsGlobalContext());
+ ASSERT(context->is_function_context());
+ ASSERT(result->IsContext());
+ return result;
+}
+
+
+Object* Heap::AllocateWithContext(Context* previous, JSObject* extension) {
+ Object* result = Heap::AllocateFixedArray(Context::MIN_CONTEXT_SLOTS);
+ if (result->IsFailure()) return result;
+ Context* context = reinterpret_cast<Context*>(result);
+ context->set_map(context_map());
+ context->set_closure(previous->closure());
+ context->set_fcontext(previous->fcontext());
+ context->set_previous(previous);
+ context->set_extension(extension);
+ context->set_global(previous->global());
+ ASSERT(!context->IsGlobalContext());
+ ASSERT(!context->is_function_context());
+ ASSERT(result->IsContext());
+ return result;
+}
+
+
+Object* Heap::AllocateStruct(InstanceType type) {
+ Map* map;
+ switch (type) {
+#define MAKE_CASE(NAME, Name, name) case NAME##_TYPE: map = name##_map(); break;
+STRUCT_LIST(MAKE_CASE)
+#undef MAKE_CASE
+ default:
+ UNREACHABLE();
+ return Failure::InternalError();
+ }
+ int size = map->instance_size();
+ AllocationSpace space =
+ (size > MaxHeapObjectSize()) ? LO_SPACE : OLD_SPACE;
+ Object* result = Heap::Allocate(map, space);
+ if (result->IsFailure()) return result;
+ Struct::cast(result)->InitializeBody(size);
+ return result;
+}
+
+
+#ifdef DEBUG
+
+void Heap::Print() {
+ if (!HasBeenSetup()) return;
+ Top::PrintStack();
+ new_space_->Print();
+ old_space_->Print();
+ code_space_->Print();
+ map_space_->Print();
+ lo_space_->Print();
+}
+
+
+void Heap::ReportCodeStatistics(const char* title) {
+ PrintF(">>>>>> Code Stats (%s) >>>>>>\n", title);
+ PagedSpace::ResetCodeStatistics();
+ // We do not look for code in new space, map space, or old space. If code
+ // somehow ends up in those spaces, we would miss it here.
+ code_space_->CollectCodeStatistics();
+ lo_space_->CollectCodeStatistics();
+ PagedSpace::ReportCodeStatistics();
+}
+
+
+// This function expects that NewSpace's allocated objects histogram is
+// populated (via a call to CollectStatistics or else as a side effect of a
+// just-completed scavenge collection).
+void Heap::ReportHeapStatistics(const char* title) {
+ USE(title);
+ PrintF(">>>>>> =============== %s (%d) =============== >>>>>>\n",
+ title, gc_count_);
+ PrintF("mark-compact GC : %d\n", mc_count_);
+ PrintF("promoted_space_limit_ %d\n", promoted_space_limit_);
+
+ PrintF("\n");
+ PrintF("Number of handles : %d\n", HandleScope::NumberOfHandles());
+ GlobalHandles::PrintStats();
+ PrintF("\n");
+
+ PrintF("Heap statistics : ");
+ MemoryAllocator::ReportStatistics();
+ PrintF("To space : ");
+ new_space_->ReportStatistics();
+ PrintF("Old space : ");
+ old_space_->ReportStatistics();
+ PrintF("Code space : ");
+ code_space_->ReportStatistics();
+ PrintF("Map space : ");
+ map_space_->ReportStatistics();
+ PrintF("Large object space : ");
+ lo_space_->ReportStatistics();
+ PrintF(">>>>>> ========================================= >>>>>>\n");
+}
+
+#endif // DEBUG
+
+bool Heap::Contains(HeapObject* value) {
+ return Contains(value->address());
+}
+
+
+bool Heap::Contains(Address addr) {
+ if (OS::IsOutsideAllocatedSpace(addr)) return false;
+ return HasBeenSetup() &&
+ (new_space_->ToSpaceContains(addr) ||
+ old_space_->Contains(addr) ||
+ code_space_->Contains(addr) ||
+ map_space_->Contains(addr) ||
+ lo_space_->SlowContains(addr));
+}
+
+
+bool Heap::InSpace(HeapObject* value, AllocationSpace space) {
+ return InSpace(value->address(), space);
+}
+
+
+bool Heap::InSpace(Address addr, AllocationSpace space) {
+ if (OS::IsOutsideAllocatedSpace(addr)) return false;
+ if (!HasBeenSetup()) return false;
+
+ switch (space) {
+ case NEW_SPACE:
+ return new_space_->ToSpaceContains(addr);
+ case OLD_SPACE:
+ return old_space_->Contains(addr);
+ case CODE_SPACE:
+ return code_space_->Contains(addr);
+ case MAP_SPACE:
+ return map_space_->Contains(addr);
+ case LO_SPACE:
+ return lo_space_->SlowContains(addr);
+ }
+
+ return false;
+}
+
+
+#ifdef DEBUG
+void Heap::Verify() {
+ ASSERT(HasBeenSetup());
+
+ VerifyPointersVisitor visitor;
+ Heap::IterateRoots(&visitor);
+
+ Heap::new_space_->Verify();
+ Heap::old_space_->Verify();
+ Heap::code_space_->Verify();
+ Heap::map_space_->Verify();
+ Heap::lo_space_->Verify();
+}
+#endif // DEBUG
+
+
+Object* Heap::LookupSymbol(Vector<const char> string) {
+ Object* symbol = NULL;
+ Object* new_table =
+ SymbolTable::cast(symbol_table_)->LookupSymbol(string, &symbol);
+ if (new_table->IsFailure()) return new_table;
+ symbol_table_ = new_table;
+ ASSERT(symbol != NULL);
+ return symbol;
+}
+
+
+Object* Heap::LookupSymbol(String* string) {
+ if (string->IsSymbol()) return string;
+ Object* symbol = NULL;
+ Object* new_table =
+ SymbolTable::cast(symbol_table_)->LookupString(string, &symbol);
+ if (new_table->IsFailure()) return new_table;
+ symbol_table_ = new_table;
+ ASSERT(symbol != NULL);
+ return symbol;
+}
+
+
+#ifdef DEBUG
+void Heap::ZapFromSpace() {
+ ASSERT(HAS_HEAP_OBJECT_TAG(kFromSpaceZapValue));
+ for (Address a = new_space_->FromSpaceLow();
+ a < new_space_->FromSpaceHigh();
+ a += kPointerSize) {
+ Memory::Address_at(a) = kFromSpaceZapValue;
+ }
+}
+#endif // DEBUG
+
+
+void Heap::IterateRSetRange(Address object_start,
+ Address object_end,
+ Address rset_start,
+ ObjectSlotCallback copy_object_func) {
+ Address object_address = object_start;
+ Address rset_address = rset_start;
+
+ // Loop over all the pointers in [object_start, object_end).
+ while (object_address < object_end) {
+ uint32_t rset_word = Memory::uint32_at(rset_address);
+
+ if (rset_word != 0) {
+ // Bits were set.
+ uint32_t result_rset = rset_word;
+
+ // Loop over all the bits in the remembered set word. Though
+ // remembered sets are sparse, faster (eg, binary) search for
+ // set bits does not seem to help much here.
+ for (int bit_offset = 0; bit_offset < kBitsPerInt; bit_offset++) {
+ uint32_t bitmask = 1 << bit_offset;
+ // Do not dereference pointers at or past object_end.
+ if ((rset_word & bitmask) != 0 && object_address < object_end) {
+ Object** object_p = reinterpret_cast<Object**>(object_address);
+ if (Heap::InFromSpace(*object_p)) {
+ copy_object_func(reinterpret_cast<HeapObject**>(object_p));
+ }
+ // If this pointer does not need to be remembered anymore, clear
+ // the remembered set bit.
+ if (!Heap::InToSpace(*object_p)) result_rset &= ~bitmask;
+ }
+ object_address += kPointerSize;
+ }
+
+ // Update the remembered set if it has changed.
+ if (result_rset != rset_word) {
+ Memory::uint32_at(rset_address) = result_rset;
+ }
+ } else {
+ // No bits in the word were set. This is the common case.
+ object_address += kPointerSize * kBitsPerInt;
+ }
+
+ rset_address += kIntSize;
+ }
+}
+
+
+void Heap::IterateRSet(PagedSpace* space, ObjectSlotCallback copy_object_func) {
+ ASSERT(Page::is_rset_in_use());
+ ASSERT(space == old_space_ || space == map_space_);
+
+ PageIterator it(space, PageIterator::PAGES_IN_USE);
+ while (it.has_next()) {
+ Page* page = it.next();
+ IterateRSetRange(page->ObjectAreaStart(), page->AllocationTop(),
+ page->RSetStart(), copy_object_func);
+ }
+}
+
+
+#ifdef DEBUG
+#define SYNCHRONIZE_TAG(tag) v->Synchronize(tag)
+#else
+#define SYNCHRONIZE_TAG(tag)
+#endif
+
+void Heap::IterateRoots(ObjectVisitor* v) {
+ IterateStrongRoots(v);
+ v->VisitPointer(reinterpret_cast<Object**>(&symbol_table_));
+ SYNCHRONIZE_TAG("symbol_table");
+}
+
+
+void Heap::IterateStrongRoots(ObjectVisitor* v) {
+#define ROOT_ITERATE(type, name) \
+ v->VisitPointer(reinterpret_cast<Object**>(&name##_));
+ STRONG_ROOT_LIST(ROOT_ITERATE);
+#undef ROOT_ITERATE
+ SYNCHRONIZE_TAG("strong_root_list");
+
+#define STRUCT_MAP_ITERATE(NAME, Name, name) \
+ v->VisitPointer(reinterpret_cast<Object**>(&name##_map_));
+ STRUCT_LIST(STRUCT_MAP_ITERATE);
+#undef STRUCT_MAP_ITERATE
+ SYNCHRONIZE_TAG("struct_map");
+
+#define SYMBOL_ITERATE(name, string) \
+ v->VisitPointer(reinterpret_cast<Object**>(&name##_));
+ SYMBOL_LIST(SYMBOL_ITERATE)
+#undef SYMBOL_ITERATE
+ SYNCHRONIZE_TAG("symbol");
+
+ Bootstrapper::Iterate(v);
+ SYNCHRONIZE_TAG("bootstrapper");
+ Top::Iterate(v);
+ SYNCHRONIZE_TAG("top");
+ Debug::Iterate(v);
+ SYNCHRONIZE_TAG("debug");
+
+ // Iterate over local handles in handle scopes.
+ HandleScopeImplementer::Iterate(v);
+ SYNCHRONIZE_TAG("handlescope");
+
+ // Iterate over the builtin code objects and code stubs in the heap. Note
+ // that it is not strictly necessary to iterate over code objects on
+ // scavenge collections. We still do it here because this same function
+ // is used by the mark-sweep collector and the deserializer.
+ Builtins::IterateBuiltins(v);
+ SYNCHRONIZE_TAG("builtins");
+
+ // Iterate over global handles.
+ GlobalHandles::IterateRoots(v);
+ SYNCHRONIZE_TAG("globalhandles");
+
+ // Iterate over pointers being held by inactive threads.
+ ThreadManager::Iterate(v);
+ SYNCHRONIZE_TAG("threadmanager");
+}
+#undef SYNCHRONIZE_TAG
+
+
+// Flag is set when the heap has been configured. The heap can be repeatedly
+// configured through the API until it is setup.
+static bool heap_configured = false;
+
+// TODO(1236194): Since the heap size is configurable on the command line
+// and through the API, we should gracefully handle the case that the heap
+// size is not big enough to fit all the initial objects.
+bool Heap::ConfigureHeap(int semispace_size, int old_gen_size) {
+ if (HasBeenSetup()) return false;
+
+ if (semispace_size > 0) semispace_size_ = semispace_size;
+ if (old_gen_size > 0) old_generation_size_ = old_gen_size;
+
+ // The new space size must be a power of two to support single-bit testing
+ // for containment.
+ semispace_size_ = NextPowerOf2(semispace_size_);
+ initial_semispace_size_ = Min(initial_semispace_size_, semispace_size_);
+ young_generation_size_ = 2 * semispace_size_;
+
+ // The old generation is paged.
+ old_generation_size_ = RoundUp(old_generation_size_, Page::kPageSize);
+
+ heap_configured = true;
+ return true;
+}
+
+
+int Heap::PromotedSpaceSize() {
+ return old_space_->Size()
+ + code_space_->Size()
+ + map_space_->Size()
+ + lo_space_->Size();
+}
+
+
+bool Heap::Setup(bool create_heap_objects) {
+ // Initialize heap spaces and initial maps and objects. Whenever something
+ // goes wrong, just return false. The caller should check the results and
+ // call Heap::TearDown() to release allocated memory.
+ //
+ // If the heap is not yet configured (eg, through the API), configure it.
+ // Configuration is based on the flags new-space-size (really the semispace
+ // size) and old-space-size if set or the initial values of semispace_size_
+ // and old_generation_size_ otherwise.
+ if (!heap_configured) {
+ if (!ConfigureHeap(FLAG_new_space_size, FLAG_old_space_size)) return false;
+ }
+
+ // Setup memory allocator and allocate an initial chunk of memory. The
+ // initial chunk is double the size of the new space to ensure that we can
+ // find a pair of semispaces that are contiguous and aligned to their size.
+ if (!MemoryAllocator::Setup(MaxCapacity())) return false;
+ void* chunk
+ = MemoryAllocator::ReserveInitialChunk(2 * young_generation_size_);
+ if (chunk == NULL) return false;
+
+ // Put the initial chunk of the old space at the start of the initial
+ // chunk, then the two new space semispaces, then the initial chunk of
+ // code space. Align the pair of semispaces to their size, which must be
+ // a power of 2.
+ ASSERT(IsPowerOf2(young_generation_size_));
+ Address old_space_start = reinterpret_cast<Address>(chunk);
+ Address new_space_start = RoundUp(old_space_start, young_generation_size_);
+ Address code_space_start = new_space_start + young_generation_size_;
+ int old_space_size = new_space_start - old_space_start;
+ int code_space_size = young_generation_size_ - old_space_size;
+
+ // Initialize new space.
+ new_space_ = new NewSpace(initial_semispace_size_, semispace_size_);
+ if (new_space_ == NULL) return false;
+ if (!new_space_->Setup(new_space_start, young_generation_size_)) return false;
+
+ // Initialize old space, set the maximum capacity to the old generation
+ // size.
+ old_space_ = new OldSpace(old_generation_size_, OLD_SPACE);
+ if (old_space_ == NULL) return false;
+ if (!old_space_->Setup(old_space_start, old_space_size)) return false;
+
+ // Initialize the code space, set its maximum capacity to the old
+ // generation size.
+ code_space_ = new OldSpace(old_generation_size_, CODE_SPACE);
+ if (code_space_ == NULL) return false;
+ if (!code_space_->Setup(code_space_start, code_space_size)) return false;
+
+ // Initialize map space.
+ map_space_ = new MapSpace(kMaxMapSpaceSize);
+ if (map_space_ == NULL) return false;
+ // Setting up a paged space without giving it a virtual memory range big
+ // enough to hold at least a page will cause it to allocate.
+ if (!map_space_->Setup(NULL, 0)) return false;
+
+ lo_space_ = new LargeObjectSpace();
+ if (lo_space_ == NULL) return false;
+ if (!lo_space_->Setup()) return false;
+
+ if (create_heap_objects) {
+ // Create initial maps.
+ if (!CreateInitialMaps()) return false;
+ if (!CreateApiObjects()) return false;
+
+ // Create initial objects
+ if (!CreateInitialObjects()) return false;
+ }
+
+ LOG(IntEvent("heap-capacity", Capacity()));
+ LOG(IntEvent("heap-available", Available()));
+
+ return true;
+}
+
+
+void Heap::TearDown() {
+ GlobalHandles::TearDown();
+
+ if (new_space_ != NULL) {
+ new_space_->TearDown();
+ delete new_space_;
+ new_space_ = NULL;
+ }
+
+ if (old_space_ != NULL) {
+ old_space_->TearDown();
+ delete old_space_;
+ old_space_ = NULL;
+ }
+
+ if (code_space_ != NULL) {
+ code_space_->TearDown();
+ delete code_space_;
+ code_space_ = NULL;
+ }
+
+ if (map_space_ != NULL) {
+ map_space_->TearDown();
+ delete map_space_;
+ map_space_ = NULL;
+ }
+
+ if (lo_space_ != NULL) {
+ lo_space_->TearDown();
+ delete lo_space_;
+ lo_space_ = NULL;
+ }
+
+ MemoryAllocator::TearDown();
+}
+
+
+void Heap::Shrink() {
+ // Try to shrink map, old, and code spaces.
+ map_space_->Shrink();
+ old_space_->Shrink();
+ code_space_->Shrink();
+}
+
+
+#ifdef DEBUG
+
+class PrintHandleVisitor: public ObjectVisitor {
+ public:
+ void VisitPointers(Object** start, Object** end) {
+ for (Object** p = start; p < end; p++)
+ PrintF(" handle %p to %p\n", p, *p);
+ }
+};
+
+void Heap::PrintHandles() {
+ PrintF("Handles:\n");
+ PrintHandleVisitor v;
+ HandleScopeImplementer::Iterate(&v);
+}
+
+#endif
+
+
+HeapIterator::HeapIterator() {
+ Init();
+}
+
+
+HeapIterator::~HeapIterator() {
+ Shutdown();
+}
+
+
+void HeapIterator::Init() {
+ // Start the iteration.
+ space_iterator_ = new SpaceIterator();
+ object_iterator_ = space_iterator_->next();
+}
+
+
+void HeapIterator::Shutdown() {
+ // Make sure the last iterator is deallocated.
+ delete space_iterator_;
+ space_iterator_ = NULL;
+ object_iterator_ = NULL;
+}
+
+
+bool HeapIterator::has_next() {
+ // No iterator means we are done.
+ if (object_iterator_ == NULL) return false;
+
+ if (object_iterator_->has_next_object()) {
+ // If the current iterator has more objects we are fine.
+ return true;
+ } else {
+ // Go though the spaces looking for one that has objects.
+ while (space_iterator_->has_next()) {
+ object_iterator_ = space_iterator_->next();
+ if (object_iterator_->has_next_object()) {
+ return true;
+ }
+ }
+ }
+ // Done with the last space.
+ object_iterator_ = NULL;
+ return false;
+}
+
+
+HeapObject* HeapIterator::next() {
+ if (has_next()) {
+ return object_iterator_->next_object();
+ } else {
+ return NULL;
+ }
+}
+
+
+void HeapIterator::reset() {
+ // Restart the iterator.
+ Shutdown();
+ Init();
+}
+
+
+//
+// HeapProfiler class implementation.
+//
+#ifdef ENABLE_LOGGING_AND_PROFILING
+void HeapProfiler::CollectStats(HeapObject* obj, HistogramInfo* info) {
+ InstanceType type = obj->map()->instance_type();
+ ASSERT(0 <= type && type <= LAST_TYPE);
+ info[type].increment_number(1);
+ info[type].increment_bytes(obj->Size());
+}
+#endif
+
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+void HeapProfiler::WriteSample() {
+ LOG(HeapSampleBeginEvent("Heap", "allocated"));
+
+ HistogramInfo info[LAST_TYPE+1];
+#define DEF_TYPE_NAME(name) info[name].set_name(#name);
+ INSTANCE_TYPE_LIST(DEF_TYPE_NAME)
+#undef DEF_TYPE_NAME
+
+ HeapIterator iterator;
+ while (iterator.has_next()) {
+ CollectStats(iterator.next(), info);
+ }
+
+ // Lump all the string types together.
+ int string_number = 0;
+ int string_bytes = 0;
+#define INCREMENT_SIZE(type, size, name) \
+ string_number += info[type].number(); \
+ string_bytes += info[type].bytes();
+ STRING_TYPE_LIST(INCREMENT_SIZE)
+#undef INCREMENT_SIZE
+ if (string_bytes > 0) {
+ LOG(HeapSampleItemEvent("STRING_TYPE", string_number, string_bytes));
+ }
+
+ for (int i = FIRST_NONSTRING_TYPE; i <= LAST_TYPE; ++i) {
+ if (info[i].bytes() > 0) {
+ LOG(HeapSampleItemEvent(info[i].name(), info[i].number(),
+ info[i].bytes()));
+ }
+ }
+
+ LOG(HeapSampleEndEvent("Heap", "allocated"));
+}
+
+
+#endif
+
+
+
+#ifdef DEBUG
+
+static bool search_for_any_global;
+static Object* search_target;
+static bool found_target;
+static List<Object*> object_stack(20);
+
+
+// Tags 0, 1, and 3 are used. Use 2 for marking visited HeapObject.
+static const int kMarkTag = 2;
+
+static void MarkObjectRecursively(Object** p);
+class MarkObjectVisitor : public ObjectVisitor {
+ public:
+ void VisitPointers(Object** start, Object** end) {
+ // Copy all HeapObject pointers in [start, end)
+ for (Object** p = start; p < end; p++) {
+ if ((*p)->IsHeapObject())
+ MarkObjectRecursively(p);
+ }
+ }
+};
+
+static MarkObjectVisitor mark_visitor;
+
+static void MarkObjectRecursively(Object** p) {
+ if (!(*p)->IsHeapObject()) return;
+
+ HeapObject* obj = HeapObject::cast(*p);
+
+ Object* map = obj->map();
+
+ if (!map->IsHeapObject()) return; // visited before
+
+ if (found_target) return; // stop if target found
+ object_stack.Add(obj);
+ if ((search_for_any_global && obj->IsJSGlobalObject()) ||
+ (!search_for_any_global && (obj == search_target))) {
+ found_target = true;
+ return;
+ }
+
+ if (obj->IsCode()) {
+ Code::cast(obj)->ConvertICTargetsFromAddressToObject();
+ }
+
+ // not visited yet
+ Map* map_p = reinterpret_cast<Map*>(HeapObject::cast(map));
+
+ Address map_addr = map_p->address();
+
+ obj->set_map(reinterpret_cast<Map*>(map_addr + kMarkTag));
+
+ MarkObjectRecursively(&map);
+
+ obj->IterateBody(map_p->instance_type(), obj->SizeFromMap(map_p),
+ &mark_visitor);
+
+ if (!found_target) // don't pop if found the target
+ object_stack.RemoveLast();
+}
+
+
+static void UnmarkObjectRecursively(Object** p);
+class UnmarkObjectVisitor : public ObjectVisitor {
+ public:
+ void VisitPointers(Object** start, Object** end) {
+ // Copy all HeapObject pointers in [start, end)
+ for (Object** p = start; p < end; p++) {
+ if ((*p)->IsHeapObject())
+ UnmarkObjectRecursively(p);
+ }
+ }
+};
+
+static UnmarkObjectVisitor unmark_visitor;
+
+static void UnmarkObjectRecursively(Object** p) {
+ if (!(*p)->IsHeapObject()) return;
+
+ HeapObject* obj = HeapObject::cast(*p);
+
+ Object* map = obj->map();
+
+ if (map->IsHeapObject()) return; // unmarked already
+
+ Address map_addr = reinterpret_cast<Address>(map);
+
+ map_addr -= kMarkTag;
+
+ ASSERT_TAG_ALIGNED(map_addr);
+
+ HeapObject* map_p = HeapObject::FromAddress(map_addr);
+
+ obj->set_map(reinterpret_cast<Map*>(map_p));
+
+ UnmarkObjectRecursively(reinterpret_cast<Object**>(&map_p));
+
+ obj->IterateBody(Map::cast(map_p)->instance_type(),
+ obj->SizeFromMap(Map::cast(map_p)),
+ &unmark_visitor);
+
+ if (obj->IsCode()) {
+ Code::cast(obj)->ConvertICTargetsFromObjectToAddress();
+ }
+}
+
+
+static void MarkRootObjectRecursively(Object** root) {
+ if (search_for_any_global) {
+ ASSERT(search_target == NULL);
+ } else {
+ ASSERT(search_target->IsHeapObject());
+ }
+ found_target = false;
+ object_stack.Clear();
+
+ MarkObjectRecursively(root);
+ UnmarkObjectRecursively(root);
+
+ if (found_target) {
+ PrintF("=====================================\n");
+ PrintF("==== Path to object ====\n");
+ PrintF("=====================================\n\n");
+
+ ASSERT(!object_stack.is_empty());
+ for (int i = 0; i < object_stack.length(); i++) {
+ if (i > 0) PrintF("\n |\n |\n V\n\n");
+ Object* obj = object_stack[i];
+ obj->Print();
+ }
+ PrintF("=====================================\n");
+ }
+}
+
+
+// Helper class for visiting HeapObjects recursively.
+class MarkRootVisitor: public ObjectVisitor {
+ public:
+ void VisitPointers(Object** start, Object** end) {
+ // Visit all HeapObject pointers in [start, end)
+ for (Object** p = start; p < end; p++) {
+ if ((*p)->IsHeapObject())
+ MarkRootObjectRecursively(p);
+ }
+ }
+};
+
+
+// Triggers a depth-first traversal of reachable objects from roots
+// and finds a path to a specific heap object and prints it.
+void Heap::TracePathToObject() {
+ search_target = NULL;
+ search_for_any_global = false;
+
+ MarkRootVisitor root_visitor;
+ IterateRoots(&root_visitor);
+}
+
+
+// Triggers a depth-first traversal of reachable objects from roots
+// and finds a path to any global object and prints it. Useful for
+// determining the source for leaks of global objects.
+void Heap::TracePathToGlobal() {
+ search_target = NULL;
+ search_for_any_global = true;
+
+ MarkRootVisitor root_visitor;
+ IterateRoots(&root_visitor);
+}
+#endif
+
+
+} } // namespace v8::internal