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// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_INTL_SUPPORT
#error Internationalization is expected to be enabled.
#endif // V8_INTL_SUPPORT
#include "src/builtins/builtins-utils-gen.h"
#include "src/code-stub-assembler.h"
namespace v8 {
namespace internal {
class IntlBuiltinsAssembler : public CodeStubAssembler {
public:
explicit IntlBuiltinsAssembler(compiler::CodeAssemblerState* state)
: CodeStubAssembler(state) {}
};
TF_BUILTIN(StringPrototypeToLowerCaseIntl, IntlBuiltinsAssembler) {
Node* const maybe_string = Parameter(Descriptor::kReceiver);
Node* const context = Parameter(Descriptor::kContext);
Node* const string =
ToThisString(context, maybe_string, "String.prototype.toLowerCase");
Label call_c(this), return_string(this), runtime(this, Label::kDeferred);
// Early exit on empty strings.
Node* const length = SmiUntag(LoadStringLength(string));
GotoIf(IntPtrEqual(length, IntPtrConstant(0)), &return_string);
// Unpack strings if possible, and bail to runtime unless we get a one-byte
// flat string.
ToDirectStringAssembler to_direct(
state(), string, ToDirectStringAssembler::kDontUnpackSlicedStrings);
to_direct.TryToDirect(&runtime);
Node* const instance_type = to_direct.instance_type();
CSA_ASSERT(this,
Word32BinaryNot(IsIndirectStringInstanceType(instance_type)));
GotoIfNot(IsOneByteStringInstanceType(instance_type), &runtime);
// For short strings, do the conversion in CSA through the lookup table.
Node* const dst = AllocateSeqOneByteString(context, length);
const int kMaxShortStringLength = 24; // Determined empirically.
GotoIf(IntPtrGreaterThan(length, IntPtrConstant(kMaxShortStringLength)),
&call_c);
{
Node* const dst_ptr = PointerToSeqStringData(dst);
VARIABLE(var_cursor, MachineType::PointerRepresentation(),
IntPtrConstant(0));
Node* const start_address = to_direct.PointerToData(&call_c);
Node* const end_address = IntPtrAdd(start_address, length);
Node* const to_lower_table_addr = ExternalConstant(
ExternalReference::intl_to_latin1_lower_table(isolate()));
VARIABLE(var_did_change, MachineRepresentation::kWord32, Int32Constant(0));
VariableList push_vars({&var_cursor, &var_did_change}, zone());
BuildFastLoop(
push_vars, start_address, end_address,
[=, &var_cursor, &var_did_change](Node* current) {
Node* c = Load(MachineType::Uint8(), current);
Node* lower = Load(MachineType::Uint8(), to_lower_table_addr,
ChangeInt32ToIntPtr(c));
StoreNoWriteBarrier(MachineRepresentation::kWord8, dst_ptr,
var_cursor.value(), lower);
var_did_change.Bind(
Word32Or(Word32NotEqual(c, lower), var_did_change.value()));
Increment(var_cursor);
},
kCharSize, INTPTR_PARAMETERS, IndexAdvanceMode::kPost);
// Return the original string if it remained unchanged in order to preserve
// e.g. internalization and private symbols (such as the preserved object
// hash) on the source string.
GotoIfNot(var_did_change.value(), &return_string);
Return(dst);
}
// Call into C for case conversion. The signature is:
// Object* ConvertOneByteToLower(String* src, String* dst, Isolate* isolate);
BIND(&call_c);
{
Node* const src = to_direct.string();
Node* const function_addr = ExternalConstant(
ExternalReference::intl_convert_one_byte_to_lower(isolate()));
Node* const isolate_ptr =
ExternalConstant(ExternalReference::isolate_address(isolate()));
MachineType type_ptr = MachineType::Pointer();
MachineType type_tagged = MachineType::AnyTagged();
Node* const result =
CallCFunction3(type_tagged, type_tagged, type_tagged, type_ptr,
function_addr, src, dst, isolate_ptr);
Return(result);
}
BIND(&return_string);
Return(string);
BIND(&runtime);
{
Node* const result =
CallRuntime(Runtime::kStringToLowerCaseIntl, context, string);
Return(result);
}
}
} // namespace internal
} // namespace v8
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