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[compiler] Use StringToDouble without allocation

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We had a way to do string to double without allocation that we were
using on StringData. Reuse that on StringRef for Strings that can
access the heap.

BUg: v8:7790
Change-Id: I30e6dace3fbf05eb8672ff1bad46f6c6d6fe1d6d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2450013
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70384}
This commit is contained in:
Santiago Aboy Solanes 2020-10-06 12:04:40 +01:00 committed by Commit Bot
parent bbecd8d5b3
commit af00c2618a
1 changed files with 22 additions and 15 deletions
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37
src/compiler/js-heap-broker.cc
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@ -845,8 +845,6 @@ class StringData : public NameData {
// element access (s[i]). The first pair component is always less than
// {length_}. The second component is never nullptr.
ZoneVector<std::pair<uint32_t, ObjectData*>> chars_as_strings_;
static constexpr int kMaxLengthForDoubleConversion = 23;
};
class SymbolData : public NameData {
@ -857,22 +855,34 @@ class SymbolData : public NameData {
}
};
namespace {
// String to double helper without heap allocation.
base::Optional<double> StringToDouble(Handle<String> object) {
const int kMaxLengthForDoubleConversion = 23;
String string = *object;
int length = string.length();
if (length <= kMaxLengthForDoubleConversion) {
const int flags = ALLOW_HEX | ALLOW_OCTAL | ALLOW_BINARY;
uc16 buffer[kMaxLengthForDoubleConversion];
String::WriteToFlat(*object, buffer, 0, length);
Vector<const uc16> v(buffer, length);
return StringToDouble(v, flags);
}
return base::nullopt;
}
} // namespace
StringData::StringData(JSHeapBroker* broker, ObjectData** storage,
Handle<String> object)
: NameData(broker, storage, object),
length_(object->length()),
first_char_(length_ > 0 ? object->Get(0) : 0),
to_number_(StringToDouble(object)),
is_external_string_(object->IsExternalString()),
is_seq_string_(object->IsSeqString()),
chars_as_strings_(broker->zone()) {
if (length_ <= kMaxLengthForDoubleConversion) {
const int flags = ALLOW_HEX | ALLOW_OCTAL | ALLOW_BINARY;
uc16 buffer[kMaxLengthForDoubleConversion];
String::WriteToFlat(*object, buffer, 0, length_);
Vector<const uc16> v(buffer, length_);
to_number_ = StringToDouble(v, flags);
}
}
chars_as_strings_(broker->zone()) {}
class InternalizedStringData : public StringData {
public:
@ -3183,10 +3193,7 @@ base::Optional<double> StringRef::ToNumber() {
broker()->mode());
AllowHandleAllocationIfNeeded allow_handle_allocation(data()->kind(),
broker()->mode());
AllowHeapAllocationIfNeeded allow_heap_allocation(data()->kind(),
broker()->mode());
int flags = ALLOW_HEX | ALLOW_OCTAL | ALLOW_BINARY;
return StringToDouble(broker()->isolate(), object(), flags);
return StringToDouble(object());
}
return data()->AsString()->to_number();
}