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Unified Diff: src/objects.cc

Issue 2625073002: Revert of Internalize strings in-place (Closed)
Patch Set: Created 3 years, 11 months ago
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Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 79eaa61a250e04e59abe087ae93fef6431519363..947a6e076f4b4deb1269c8a8dc703168b20ccae9 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -2512,7 +2512,7 @@
Heap* heap = GetHeap();
bool is_one_byte = this->IsOneByteRepresentation();
bool is_internalized = this->IsInternalizedString();
- bool has_pointers = StringShape(this).IsIndirect();
+ bool has_pointers = this->IsConsString() || this->IsSlicedString();
// Morph the string to an external string by replacing the map and
// reinitializing the fields. This won't work if the space the existing
@@ -2584,7 +2584,7 @@
if (size < ExternalString::kShortSize) return false;
Heap* heap = GetHeap();
bool is_internalized = this->IsInternalizedString();
- bool has_pointers = StringShape(this).IsIndirect();
+ bool has_pointers = this->IsConsString() || this->IsSlicedString();
// Morph the string to an external string by replacing the map and
// reinitializing the fields. This won't work if the space the existing
@@ -10928,7 +10928,11 @@
return isolate->factory()->NewSubString(string, left, right);
}
-bool String::LooksValid() { return GetIsolate()->heap()->Contains(this); }
+bool String::LooksValid() {
+ if (!GetIsolate()->heap()->Contains(this)) return false;
+ return true;
+}
+
// static
MaybeHandle<String> Name::ToFunctionName(Handle<Name> name) {
@@ -11062,20 +11066,14 @@
}
string = cons->first();
shape = StringShape(string);
- } else if (shape.representation_tag() == kSlicedStringTag) {
+ }
+ if (shape.representation_tag() == kSlicedStringTag) {
SlicedString* slice = SlicedString::cast(string);
offset = slice->offset();
string = slice->parent();
shape = StringShape(string);
DCHECK(shape.representation_tag() != kConsStringTag &&
shape.representation_tag() != kSlicedStringTag);
- }
- if (shape.representation_tag() == kThinStringTag) {
- ThinString* thin = ThinString::cast(string);
- string = thin->actual();
- shape = StringShape(string);
- DCHECK(!shape.IsCons());
- DCHECK(!shape.IsSliced());
}
if (shape.encoding_tag() == kOneByteStringTag) {
const uint8_t* start;
@@ -11162,7 +11160,6 @@
return slice->parent()->GetTwoByteData(start + slice->offset());
}
case kConsStringTag:
- case kThinStringTag:
UNREACHABLE();
return NULL;
}
@@ -11429,7 +11426,6 @@
return 0;
}
-uint16_t ThinString::ThinStringGet(int index) { return actual()->Get(index); }
uint16_t SlicedString::SlicedStringGet(int index) {
return parent()->Get(offset() + index);
@@ -11524,10 +11520,6 @@
WriteToFlat(slice->parent(), sink, from + offset, to + offset);
return;
}
- case kOneByteStringTag | kThinStringTag:
- case kTwoByteStringTag | kThinStringTag:
- source = ThinString::cast(source)->actual();
- break;
}
}
}
@@ -11749,17 +11741,6 @@
if (len != other->length()) return false;
if (len == 0) return true;
- // Fast check: if at least one ThinString is involved, dereference it/them
- // and restart.
- if (this->IsThinString() || other->IsThinString()) {
- if (other->IsThinString()) other = ThinString::cast(other)->actual();
- if (this->IsThinString()) {
- return ThinString::cast(this)->actual()->Equals(other);
- } else {
- return this->Equals(other);
- }
- }
-
// Fast check: if hash code is computed for both strings
// a fast negative check can be performed.
if (HasHashCode() && other->HasHashCode()) {
@@ -11800,14 +11781,6 @@
int one_length = one->length();
if (one_length != two->length()) return false;
if (one_length == 0) return true;
-
- // Fast check: if at least one ThinString is involved, dereference it/them
- // and restart.
- if (one->IsThinString() || two->IsThinString()) {
- if (one->IsThinString()) one = handle(ThinString::cast(*one)->actual());
- if (two->IsThinString()) two = handle(ThinString::cast(*two)->actual());
- return String::Equals(one, two);
- }
// Fast check: if hash code is computed for both strings
// a fast negative check can be performed.
@@ -16864,14 +16837,6 @@
DCHECK(string_->IsInternalizedString());
return string_;
}
- // External strings get special treatment, to avoid copying their contents.
- if (string_->IsExternalOneByteString()) {
- return isolate->factory()
- ->InternalizeExternalString<ExternalOneByteString>(string_);
- } else if (string_->IsExternalTwoByteString()) {
- return isolate->factory()
- ->InternalizeExternalString<ExternalTwoByteString>(string_);
- }
// Otherwise allocate a new internalized string.
return isolate->factory()->NewInternalizedStringImpl(
string_, string_->length(), string_->hash_field());
@@ -16881,7 +16846,6 @@
return String::cast(obj)->Hash();
}
- private:
Handle<String> string_;
};
@@ -17816,9 +17780,6 @@
if (string->IsInternalizedString()) {
return string;
}
- if (string->IsThinString()) {
- return handle(Handle<ThinString>::cast(string)->actual(), isolate);
- }
return LookupStringIfExists(isolate, string);
}
@@ -17865,72 +17826,31 @@
isolate->heap()->SetRootStringTable(*table);
}
-namespace {
-
-template <class StringClass>
-void MigrateExternalStringResource(Isolate* isolate, Handle<String> from,
- Handle<String> to) {
- Handle<StringClass> cast_from = Handle<StringClass>::cast(from);
- Handle<StringClass> cast_to = Handle<StringClass>::cast(to);
- const typename StringClass::Resource* to_resource = cast_to->resource();
- if (to_resource == nullptr) {
- // |to| is a just-created internalized copy of |from|. Migrate the resource.
- cast_to->set_resource(cast_from->resource());
- // Zap |from|'s resource pointer to reflect the fact that |from| has
- // relinquished ownership of its resource.
- cast_from->set_resource(nullptr);
- } else if (to_resource != cast_from->resource()) {
- // |to| already existed and has its own resource. Finalize |from|.
- isolate->heap()->FinalizeExternalString(*from);
- }
-}
-
-} // namespace
Handle<String> StringTable::LookupString(Isolate* isolate,
Handle<String> string) {
- if (string->IsThinString()) {
- DCHECK(Handle<ThinString>::cast(string)->actual()->IsInternalizedString());
- return handle(Handle<ThinString>::cast(string)->actual(), isolate);
- }
if (string->IsConsString() && string->IsFlat()) {
- string = handle(Handle<ConsString>::cast(string)->first(), isolate);
+ string = String::Flatten(string);
if (string->IsInternalizedString()) return string;
}
InternalizedStringKey key(string);
Handle<String> result = LookupKey(isolate, &key);
- if (string->IsExternalString()) {
- if (result->IsExternalOneByteString()) {
- MigrateExternalStringResource<ExternalOneByteString>(isolate, string,
- result);
- } else if (result->IsExternalTwoByteString()) {
- MigrateExternalStringResource<ExternalTwoByteString>(isolate, string,
- result);
- }
- }
-
- // The LookupKey() call above tries to internalize the string in-place.
- // In cases where that wasn't possible (e.g. new-space strings), turn them
- // into ThinStrings referring to their internalized versions now.
- if (!string->IsInternalizedString()) {
+ if (string->IsConsString()) {
+ Handle<ConsString> cons = Handle<ConsString>::cast(string);
+ cons->set_first(*result);
+ cons->set_second(isolate->heap()->empty_string());
+ } else if (string->IsSlicedString()) {
+ STATIC_ASSERT(ConsString::kSize == SlicedString::kSize);
DisallowHeapAllocation no_gc;
bool one_byte = result->IsOneByteRepresentation();
- Handle<Map> map = one_byte ? isolate->factory()->thin_one_byte_string_map()
- : isolate->factory()->thin_string_map();
- int old_size = string->Size();
- DCHECK(old_size >= ThinString::kSize);
- string->synchronized_set_map(*map);
- Handle<ThinString> thin = Handle<ThinString>::cast(string);
- thin->set_actual(*result);
- Address thin_end = thin->address() + ThinString::kSize;
- int size_delta = old_size - ThinString::kSize;
- if (size_delta != 0) {
- Heap* heap = isolate->heap();
- heap->CreateFillerObjectAt(thin_end, size_delta, ClearRecordedSlots::kNo);
- heap->AdjustLiveBytes(*thin, -size_delta);
- }
+ Handle<Map> map = one_byte ? isolate->factory()->cons_one_byte_string_map()
+ : isolate->factory()->cons_string_map();
+ string->set_map(*map);
+ Handle<ConsString> cons = Handle<ConsString>::cast(string);
+ cons->set_first(*result);
+ cons->set_second(isolate->heap()->empty_string());
}
return result;
}
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