Merge changes up to V8 version 2.1.3 into the partial snapshots

src/heap.cc

 // Copyright 2009 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
@@ skipping 28 matching lines @@
 #include "natives.h"
 #include "scanner.h"
 #include "scopeinfo.h"
 #include "snapshot.h"
 #include "v8threads.h"
 #if V8_TARGET_ARCH_ARM && V8_NATIVE_REGEXP
 #include "regexp-macro-assembler.h"
 #include "arm/regexp-macro-assembler-arm.h"
 #endif
 
+
 namespace v8 {
 namespace internal {
 
 
 String* Heap::hidden_symbol_;
 Object* Heap::roots_[Heap::kRootListLength];
 
 
 NewSpace Heap::new_space_;
 OldSpace* Heap::old_pointer_space_ = NULL;
@@ skipping 49 matching lines @@
 int Heap::survived_since_last_expansion_ = 0;
 int Heap::external_allocation_limit_ = 0;
 
 Heap::HeapState Heap::gc_state_ = NOT_IN_GC;
 
 int Heap::mc_count_ = 0;
 int Heap::gc_count_ = 0;
 
 int Heap::always_allocate_scope_depth_ = 0;
 int Heap::linear_allocation_scope_depth_ = 0;
-bool Heap::context_disposed_pending_ = false;
+int Heap::contexts_disposed_ = 0;
 
 #ifdef DEBUG
 bool Heap::allocation_allowed_ = true;
 
 int Heap::allocation_timeout_ = 0;
 bool Heap::disallow_allocation_failure_ = false;
 #endif  // DEBUG
 
 
 int Heap::Capacity() {
@@ skipping 235 matching lines @@
 void Heap::CollectAllGarbage(bool force_compaction) {
   // Since we are ignoring the return value, the exact choice of space does
   // not matter, so long as we do not specify NEW_SPACE, which would not
   // cause a full GC.
   MarkCompactCollector::SetForceCompaction(force_compaction);
   CollectGarbage(0, OLD_POINTER_SPACE);
   MarkCompactCollector::SetForceCompaction(false);
 }
 
 
-void Heap::CollectAllGarbageIfContextDisposed() {
-  // If the garbage collector interface is exposed through the global
-  // gc() function, we avoid being clever about forcing GCs when
-  // contexts are disposed and leave it to the embedder to make
-  // informed decisions about when to force a collection.
-  if (!FLAG_expose_gc && context_disposed_pending_) {
-    HistogramTimerScope scope(&Counters::gc_context);
-    CollectAllGarbage(false);
-  }
-  context_disposed_pending_ = false;
-}
-
-
-void Heap::NotifyContextDisposed() {
-  context_disposed_pending_ = true;
-}
-
-
 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.
@@ skipping 149 matching lines @@
   V8::FatalProcessOutOfMemory("Committing semi space failed.");
 }
 
 
 void Heap::PerformGarbageCollection(AllocationSpace space,
                                     GarbageCollector collector,
                                     GCTracer* tracer) {
   VerifySymbolTable();
   if (collector == MARK_COMPACTOR && global_gc_prologue_callback_) {
     ASSERT(!allocation_allowed_);
+    GCTracer::ExternalScope scope(tracer);
     global_gc_prologue_callback_();
   }
   EnsureFromSpaceIsCommitted();
+
+  // Perform mark-sweep with optional compaction.
   if (collector == MARK_COMPACTOR) {
     MarkCompact(tracer);
+  }
 
+  // Always perform a scavenge to make room in new space.
+  Scavenge();
+
+  // Update the old space promotion limits after the scavenge due to
+  // promotions during scavenge.
+  if (collector == MARK_COMPACTOR) {
     int old_gen_size = PromotedSpaceSize();
     old_gen_promotion_limit_ =
         old_gen_size + Max(kMinimumPromotionLimit, old_gen_size / 3);
     old_gen_allocation_limit_ =
         old_gen_size + Max(kMinimumAllocationLimit, old_gen_size / 2);
     old_gen_exhausted_ = false;
   }
-  Scavenge();
 
   Counters::objs_since_last_young.Set(0);
 
   if (collector == MARK_COMPACTOR) {
     DisableAssertNoAllocation allow_allocation;
+    GCTracer::ExternalScope scope(tracer);
     GlobalHandles::PostGarbageCollectionProcessing();
   }
 
   // Update relocatables.
   Relocatable::PostGarbageCollectionProcessing();
 
   if (collector == MARK_COMPACTOR) {
     // Register the amount of external allocated memory.
     amount_of_external_allocated_memory_at_last_global_gc_ =
         amount_of_external_allocated_memory_;
   }
 
   if (collector == MARK_COMPACTOR && global_gc_epilogue_callback_) {
     ASSERT(!allocation_allowed_);
+    GCTracer::ExternalScope scope(tracer);
     global_gc_epilogue_callback_();
   }
   VerifySymbolTable();
 }
 
 
 void Heap::MarkCompact(GCTracer* tracer) {
   gc_state_ = MARK_COMPACT;
   mc_count_++;
   tracer->set_full_gc_count(mc_count_);
   LOG(ResourceEvent("markcompact", "begin"));
 
   MarkCompactCollector::Prepare(tracer);
 
   bool is_compacting = MarkCompactCollector::IsCompacting();
 
   MarkCompactPrologue(is_compacting);
 
   MarkCompactCollector::CollectGarbage();
 
   MarkCompactEpilogue(is_compacting);
 
   LOG(ResourceEvent("markcompact", "end"));
 
   gc_state_ = NOT_IN_GC;
 
   Shrink();
 
   Counters::objs_since_last_full.Set(0);
-  context_disposed_pending_ = false;
+
+  contexts_disposed_ = 0;
 }
 
 
 void Heap::MarkCompactPrologue(bool is_compacting) {
   // At any old GC clear the keyed lookup cache to enable collection of unused
   // maps.
   KeyedLookupCache::Clear();
   ContextSlotCache::Clear();
   DescriptorLookupCache::Clear();
 
@@ skipping 580 matching lines @@
   // If the map object is aligned fill the padding area with Smi 0 objects.
   if (Map::kPadStart < Map::kSize) {
     memset(reinterpret_cast<byte*>(map) + Map::kPadStart - kHeapObjectTag,
            0,
            Map::kSize - Map::kPadStart);
   }
   return map;
 }
 
 
+Object* Heap::AllocateCodeCache() {
+  Object* result = AllocateStruct(CODE_CACHE_TYPE);
+  if (result->IsFailure()) return result;
+  CodeCache* code_cache = CodeCache::cast(result);
+  code_cache->set_default_cache(empty_fixed_array());
+  code_cache->set_normal_type_cache(undefined_value());
+  return code_cache;
+}
+
+
 const Heap::StringTypeTable Heap::string_type_table[] = {
 #define STRING_TYPE_ELEMENT(type, size, name, camel_name)                      \
   {type, size, k##camel_name##MapRootIndex},
   STRING_TYPE_LIST(STRING_TYPE_ELEMENT)
 #undef STRING_TYPE_ELEMENT
 };
 
 
 const Heap::ConstantSymbolTable Heap::constant_symbol_table[] = {
 #define CONSTANT_SYMBOL_ELEMENT(name, contents)                                \
@@ skipping 396 matching lines @@
   // is set to avoid expanding the dictionary during bootstrapping.
   obj = NumberDictionary::Allocate(64);
   if (obj->IsFailure()) return false;
   set_non_monomorphic_cache(NumberDictionary::cast(obj));
 
   CreateFixedStubs();
 
   if (InitializeNumberStringCache()->IsFailure()) return false;
 
   // Allocate cache for single character strings.
-  obj = AllocateFixedArray(String::kMaxAsciiCharCode+1);
+  obj = AllocateFixedArray(String::kMaxAsciiCharCode+1, TENURED);
   if (obj->IsFailure()) return false;
   set_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;
   set_natives_source_cache(FixedArray::cast(obj));
 
   // Handling of script id generation is in Factory::NewScript.
   set_last_script_id(undefined_value());
@@ skipping 13 matching lines @@
   return true;
 }
 
 
 Object* Heap::InitializeNumberStringCache() {
   // Compute the size of the number string cache based on the max heap size.
   // max_semispace_size_ == 512 KB => number_string_cache_size = 32.
   // max_semispace_size_ ==   8 MB => number_string_cache_size = 16KB.
   int number_string_cache_size = max_semispace_size_ / 512;
   number_string_cache_size = Max(32, Min(16*KB, number_string_cache_size));
-  Object* obj = AllocateFixedArray(number_string_cache_size * 2);
+  Object* obj = AllocateFixedArray(number_string_cache_size * 2, TENURED);
   if (!obj->IsFailure()) set_number_string_cache(FixedArray::cast(obj));
   return obj;
 }
 
 
 void Heap::FlushNumberStringCache() {
   // Flush the number to string cache.
   int len = number_string_cache()->length();
   for (int i = 0; i < len; i++) {
     number_string_cache()->set_undefined(i);
@@ skipping 302 matching lines @@
   cons_string->set_length(length);
   cons_string->set_hash_field(String::kEmptyHashField);
   cons_string->set_first(first, mode);
   cons_string->set_second(second, mode);
   return result;
 }
 
 
 Object* Heap::AllocateSubString(String* buffer,
                                 int start,
-                                int end) {
+                                int end,
+                                PretenureFlag pretenure) {
   int length = end - start;
 
   if (length == 1) {
     return Heap::LookupSingleCharacterStringFromCode(
         buffer->Get(start));
   } else if (length == 2) {
     // Optimization for 2-byte strings often used as keys in a decompression
     // dictionary.  Check whether we already have the string in the symbol
     // table to prevent creation of many unneccesary strings.
     unsigned c1 = buffer->Get(start);
     unsigned c2 = buffer->Get(start + 1);
     return MakeOrFindTwoCharacterString(c1, c2);
   }
 
   // Make an attempt to flatten the buffer to reduce access time.
-  if (!buffer->IsFlat()) {
-    buffer->TryFlatten();
-  }
+  buffer->TryFlatten();
 
   Object* result = buffer->IsAsciiRepresentation()
-      ? AllocateRawAsciiString(length)
-      : AllocateRawTwoByteString(length);
+      ? AllocateRawAsciiString(length, pretenure )
+      : AllocateRawTwoByteString(length, pretenure);
   if (result->IsFailure()) return result;
   String* string_result = String::cast(result);
-
   // Copy the characters into the new object.
   if (buffer->IsAsciiRepresentation()) {
     ASSERT(string_result->IsAsciiRepresentation());
     char* dest = SeqAsciiString::cast(string_result)->GetChars();
     String::WriteToFlat(buffer, dest, start, end);
   } else {
     ASSERT(string_result->IsTwoByteRepresentation());
     uc16* dest = SeqTwoByteString::cast(string_result)->GetChars();
     String::WriteToFlat(buffer, dest, start, end);
   }
@@ skipping 929 matching lines @@
   array->set_length(length);
   Object* value = undefined_value();
   for (int index = 0; index < length; index++) {
     ASSERT(!Heap::InNewSpace(value));  // value = undefined
     array->set(index, value, SKIP_WRITE_BARRIER);
   }
   return array;
 }
 
 
+Object* Heap::AllocateUninitializedFixedArray(int length) {
+  if (length == 0) return empty_fixed_array();
+
+  Object* obj = AllocateRawFixedArray(length);
+  if (obj->IsFailure()) return obj;
+
+  reinterpret_cast<FixedArray*>(obj)->set_map(fixed_array_map());
+  FixedArray::cast(obj)->set_length(length);
+  return obj;
+}
+
+
 Object* Heap::AllocateFixedArrayWithHoles(int length) {
   if (length == 0) return empty_fixed_array();
   Object* result = AllocateRawFixedArray(length);
   if (!result->IsFailure()) {
     // Initialize header.
     reinterpret_cast<Array*>(result)->set_map(fixed_array_map());
     FixedArray* array = FixedArray::cast(result);
     array->set_length(length);
     // Initialize body.
-    Object* value = the_hole_value();
-    for (int index = 0; index < length; index++)  {
-      ASSERT(!Heap::InNewSpace(value));  // value = the hole
-      array->set(index, value, SKIP_WRITE_BARRIER);
-    }
+    ASSERT(!Heap::InNewSpace(the_hole_value()));
+    MemsetPointer(HeapObject::RawField(array, FixedArray::kHeaderSize),
+                  the_hole_value(),
+                  length);
   }
   return result;
 }
 
 
-Object* Heap::AllocateHashTable(int length) {
-  Object* result = Heap::AllocateFixedArray(length);
+Object* Heap::AllocateHashTable(int length, PretenureFlag pretenure) {
+  Object* result = Heap::AllocateFixedArray(length, pretenure);
   if (result->IsFailure()) return result;
   reinterpret_cast<Array*>(result)->set_map(hash_table_map());
   ASSERT(result->IsHashTable());
   return result;
 }
 
 
 Object* Heap::AllocateGlobalContext() {
   Object* result = Heap::AllocateFixedArray(Context::GLOBAL_CONTEXT_SLOTS);
   if (result->IsFailure()) return result;
@@ skipping 62 matching lines @@
 }
 
 
 bool Heap::IdleNotification() {
   static const int kIdlesBeforeScavenge = 4;
   static const int kIdlesBeforeMarkSweep = 7;
   static const int kIdlesBeforeMarkCompact = 8;
   static int number_idle_notifications = 0;
   static int last_gc_count = gc_count_;
 
+  bool uncommit = true;
   bool finished = false;
 
   if (last_gc_count == gc_count_) {
     number_idle_notifications++;
   } else {
     number_idle_notifications = 0;
     last_gc_count = gc_count_;
   }
 
   if (number_idle_notifications == kIdlesBeforeScavenge) {
-    CollectGarbage(0, NEW_SPACE);
+    if (contexts_disposed_ > 0) {
+      HistogramTimerScope scope(&Counters::gc_context);
+      CollectAllGarbage(false);
+    } else {
+      CollectGarbage(0, NEW_SPACE);
+    }
     new_space_.Shrink();
     last_gc_count = gc_count_;
 
   } else if (number_idle_notifications == kIdlesBeforeMarkSweep) {
     // Before doing the mark-sweep collections we clear the
     // compilation cache to avoid hanging on to source code and
     // generated code for cached functions.
     CompilationCache::Clear();
 
     CollectAllGarbage(false);
     new_space_.Shrink();
     last_gc_count = gc_count_;
 
   } else if (number_idle_notifications == kIdlesBeforeMarkCompact) {
     CollectAllGarbage(true);
     new_space_.Shrink();
     last_gc_count = gc_count_;
     number_idle_notifications = 0;
     finished = true;
+
+  } else if (contexts_disposed_ > 0) {
+    if (FLAG_expose_gc) {
+      contexts_disposed_ = 0;
+    } else {
+      HistogramTimerScope scope(&Counters::gc_context);
+      CollectAllGarbage(false);
+      last_gc_count = gc_count_;
+    }
+    // If this is the first idle notification, we reset the
+    // notification count to avoid letting idle notifications for
+    // context disposal garbage collections start a potentially too
+    // aggressive idle GC cycle.
+    if (number_idle_notifications <= 1) {
+      number_idle_notifications = 0;
+      uncommit = false;
+    }
   }
 
-  // Uncommit unused memory in new space.
-  Heap::UncommitFromSpace();
+  // Make sure that we have no pending context disposals and
+  // conditionally uncommit from space.
+  ASSERT(contexts_disposed_ == 0);
+  if (uncommit) Heap::UncommitFromSpace();
   return finished;
 }
 
 
 #ifdef DEBUG
 
 void Heap::Print() {
   if (!HasBeenSetup()) return;
   Top::PrintStack();
   AllSpaces spaces;
@@ skipping 941 matching lines @@
 
   MarkRootVisitor root_visitor;
   IterateRoots(&root_visitor, VISIT_ONLY_STRONG);
 }
 #endif
 
 
 GCTracer::GCTracer()
     : start_time_(0.0),
       start_size_(0.0),
+      external_time_(0.0),
       gc_count_(0),
       full_gc_count_(0),
       is_compacting_(false),
       marked_count_(0) {
   // These two fields reflect the state of the previous full collection.
   // Set them before they are changed by the collector.
   previous_has_compacted_ = MarkCompactCollector::HasCompacted();
   previous_marked_count_ = MarkCompactCollector::previous_marked_count();
   if (!FLAG_trace_gc) return;
   start_time_ = OS::TimeCurrentMillis();
   start_size_ = SizeOfHeapObjects();
 }
 
 
 GCTracer::~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_));
+  int time = static_cast<int>(OS::TimeCurrentMillis() - start_time_);
+  int external_time = static_cast<int>(external_time_);
+  PrintF("%s %.1f -> %.1f MB, ",
+         CollectorString(), start_size_, SizeOfHeapObjects());
+  if (external_time > 0) PrintF("%d / ", external_time);
+  PrintF("%d ms.\n", time);
 
 #if defined(ENABLE_LOGGING_AND_PROFILING)
   Heap::PrintShortHeapStatistics();
 #endif
 }
 
 
 const char* GCTracer::CollectorString() {
   switch (collector_) {
     case SCAVENGER:
@@ skipping 118 matching lines @@
 void ExternalStringTable::TearDown() {
   new_space_strings_.Free();
   old_space_strings_.Free();
 }
 
 
 List<Object*> ExternalStringTable::new_space_strings_;
 List<Object*> ExternalStringTable::old_space_strings_;
 
 } }  // namespace v8::internal