Author: [email protected]
Date: Tue Apr 14 05:00:56 2009
New Revision: 1699
Modified:
branches/bleeding_edge/src/heap.cc
branches/bleeding_edge/src/mark-compact.cc
branches/bleeding_edge/src/objects.cc
branches/bleeding_edge/src/objects.h
Log:
Verify the symbol table contents before and after all
GCs (not just mark-compacts) and make the mark-compact
shortcutting of cons-strings identical to the scavenge
version.
Review URL: http://codereview.chromium.org/67125
Modified: branches/bleeding_edge/src/heap.cc
==============================================================================
--- branches/bleeding_edge/src/heap.cc (original)
+++ branches/bleeding_edge/src/heap.cc Tue Apr 14 05:00:56 2009
@@ -374,9 +374,34 @@
}
+static void VerifySymbolTable() {
+#ifdef DEBUG
+ // Helper class for verifying the symbol table.
+ class SymbolTableVerifier : public ObjectVisitor {
+ public:
+ SymbolTableVerifier() { }
+ void VisitPointers(Object** start, Object** end) {
+ // Visit all HeapObject pointers in [start, end).
+ for (Object** p = start; p < end; p++) {
+ if ((*p)->IsHeapObject()) {
+ // Check that the symbol is actually a symbol.
+ ASSERT((*p)->IsNull() || (*p)->IsUndefined() ||
(*p)->IsSymbol());
+ }
+ }
+ }
+ };
+
+ SymbolTableVerifier verifier;
+ SymbolTable* symbol_table = SymbolTable::cast(Heap::symbol_table());
+ symbol_table->IterateElements(&verifier);
+#endif // DEBUG
+}
+
+
void Heap::PerformGarbageCollection(AllocationSpace space,
GarbageCollector collector,
GCTracer* tracer) {
+ VerifySymbolTable();
if (collector == MARK_COMPACTOR && global_gc_prologue_callback_) {
ASSERT(!allocation_allowed_);
global_gc_prologue_callback_();
@@ -421,6 +446,7 @@
ASSERT(!allocation_allowed_);
global_gc_epilogue_callback_();
}
+ VerifySymbolTable();
}
@@ -813,18 +839,9 @@
static inline bool IsShortcutCandidate(HeapObject* object, Map* map) {
- // A ConsString with an empty string as the right side is a
- // candidate for being shortcut by the scavenger unless it is a
- // symbol. It's not common to have non-flat symbols, so we do not
- // shortcut them thereby avoiding turning symbols into strings.
- ASSERT(kNotStringTag != 0 && kSymbolTag != 0);
- static const uint32_t kShortcutTypeMask =
- kIsNotStringMask |
- kIsSymbolMask |
- kStringRepresentationMask;
ASSERT(object->map() == map);
InstanceType type = map->instance_type();
- if ((type & kShortcutTypeMask) != kConsStringTag) return false;
+ if ((type & kShortcutTypeMask) != kShortcutTypeTag) return false;
ASSERT(object->IsString() && !object->IsSymbol());
return ConsString::cast(object)->unchecked_second() ==
Heap::empty_string();
}
Modified: branches/bleeding_edge/src/mark-compact.cc
==============================================================================
--- branches/bleeding_edge/src/mark-compact.cc (original)
+++ branches/bleeding_edge/src/mark-compact.cc Tue Apr 14 05:00:56 2009
@@ -96,24 +96,6 @@
}
-#ifdef DEBUG
-// Helper class for verifying the symbol table.
-class SymbolTableVerifier : public ObjectVisitor {
- public:
- SymbolTableVerifier() { }
- void VisitPointers(Object** start, Object** end) {
- // Visit all HeapObject pointers in [start, end).
- for (Object** p = start; p < end; p++) {
- if ((*p)->IsHeapObject()) {
- // Check that the symbol is actually a symbol.
- ASSERT((*p)->IsNull() || (*p)->IsUndefined() || (*p)->IsSymbol());
- }
- }
- }
-};
-#endif // DEBUG
-
-
void MarkCompactCollector::Prepare(GCTracer* tracer) {
// Rather than passing the tracer around we stash it in a static member
// variable.
@@ -166,10 +148,6 @@
}
#ifdef DEBUG
- SymbolTable* symbol_table = SymbolTable::cast(Heap::symbol_table());
- SymbolTableVerifier v;
- symbol_table->IterateElements(&v);
-
live_bytes_ = 0;
live_young_objects_ = 0;
live_old_pointer_objects_ = 0;
@@ -183,10 +161,6 @@
void MarkCompactCollector::Finish() {
#ifdef DEBUG
- SymbolTable* symbol_table = SymbolTable::cast(Heap::symbol_table());
- SymbolTableVerifier v;
- symbol_table->IterateElements(&v);
-
ASSERT(state_ == SWEEP_SPACES || state_ == REBUILD_RSETS);
state_ = IDLE;
#endif
@@ -246,13 +220,7 @@
MapWord map_word = object->map_word();
map_word.ClearMark();
InstanceType type = map_word.ToMap()->instance_type();
- if (type >= FIRST_NONSTRING_TYPE || (type & kIsSymbolMask) != 0) {
- return object;
- }
-
- StringRepresentationTag rep =
- static_cast<StringRepresentationTag>(type &
kStringRepresentationMask);
- if (rep != kConsStringTag) return object;
+ if ((type & kShortcutTypeMask) != kShortcutTypeTag) return object;
Object* second =
reinterpret_cast<ConsString*>(object)->unchecked_second();
if (reinterpret_cast<String*>(second) != Heap::empty_string()) return
object;
Modified: branches/bleeding_edge/src/objects.cc
==============================================================================
--- branches/bleeding_edge/src/objects.cc (original)
+++ branches/bleeding_edge/src/objects.cc Tue Apr 14 05:00:56 2009
@@ -679,7 +679,7 @@
SmartPointer<uc16> smart_chars = this->ToWideCString();
ASSERT(memcmp(*smart_chars,
resource->data(),
- resource->length()*sizeof(**smart_chars)) == 0);
+ resource->length() * sizeof(**smart_chars)) == 0);
}
#endif // DEBUG
@@ -6304,7 +6304,7 @@
if (StringShape(string_).IsCons()) {
ConsString* cons_string = ConsString::cast(string_);
cons_string->TryFlatten();
- if (cons_string->second() == Heap::empty_string()) {
+ if (cons_string->second()->length() == 0) {
string_ = cons_string->first();
}
}
@@ -6312,6 +6312,7 @@
Map* map = Heap::SymbolMapForString(string_);
if (map != NULL) {
string_->set_map(map);
+ ASSERT(string_->IsSymbol());
return string_;
}
// Otherwise allocate a new symbol.
Modified: branches/bleeding_edge/src/objects.h
==============================================================================
--- branches/bleeding_edge/src/objects.h (original)
+++ branches/bleeding_edge/src/objects.h Tue Apr 14 05:00:56 2009
@@ -441,6 +441,20 @@
kExternalStringTag = 0x3
};
+
+// A ConsString with an empty string as the right side is a candidate
+// for being shortcut by the garbage collector unless it is a
+// symbol. It's not common to have non-flat symbols, so we do not
+// shortcut them thereby avoiding turning symbols into strings. See
+// heap.cc and mark-compact.cc.
+STATIC_ASSERT(kNotStringTag != 0 && kSymbolTag != 0);
+const uint32_t kShortcutTypeMask =
+ kIsNotStringMask |
+ kIsSymbolMask |
+ kStringRepresentationMask;
+const uint32_t kShortcutTypeTag = kConsStringTag;
+
+
enum InstanceType {
SHORT_SYMBOL_TYPE = kShortStringTag | kSymbolTag | kSeqStringTag,
MEDIUM_SYMBOL_TYPE = kMediumStringTag | kSymbolTag | kSeqStringTag,
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