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MIPS64: Fix string stubs.

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An innocent-looking change in 'c63e50ed Reland Update V8 DEPS.' exposed
latent bugs in SubStringStub and StringCharFromCodeGenerator.

TEST=mjsunit/string-replace, msjunit/string-split, others....
BUG=

Review URL: https://codereview.chromium.org/1233903003

Cr-Commit-Position: refs/heads/master@{#29731}
This commit is contained in:
paul.lind 2015-07-17 06:56:44 -07:00 committed by Commit bot
parent 8bde6b1920
commit 88214f1bf8
1 changed files with 9 additions and 19 deletions
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28
src/mips64/code-stubs-mips64.cc
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@ -3200,25 +3200,17 @@ void StringCharCodeAtGenerator::GenerateSlow(
void StringCharFromCodeGenerator::GenerateFast(MacroAssembler* masm) {
// Fast case of Heap::LookupSingleCharacterStringFromCode.
DCHECK(!a4.is(result_));
DCHECK(!a4.is(code_));
STATIC_ASSERT(kSmiTag == 0);
DCHECK(base::bits::IsPowerOfTwo32(String::kMaxOneByteCharCodeU + 1));
__ And(a4, code_, Operand(kSmiTagMask |
((~String::kMaxOneByteCharCodeU) << kSmiTagSize)));
__ Branch(&slow_case_, ne, a4, Operand(zero_reg));
__ JumpIfNotSmi(code_, &slow_case_);
__ Branch(&slow_case_, hi, code_,
Operand(Smi::FromInt(String::kMaxOneByteCharCode)));
__ LoadRoot(result_, Heap::kSingleCharacterStringCacheRootIndex);
// At this point code register contains smi tagged one_byte char code.
STATIC_ASSERT(kSmiTag == 0);
__ SmiScale(a4, code_, kPointerSizeLog2);
__ Daddu(result_, result_, a4);
__ SmiScale(at, code_, kPointerSizeLog2);
__ Daddu(result_, result_, at);
__ ld(result_, FieldMemOperand(result_, FixedArray::kHeaderSize));
__ LoadRoot(a4, Heap::kUndefinedValueRootIndex);
__ Branch(&slow_case_, eq, result_, Operand(a4));
__ LoadRoot(at, Heap::kUndefinedValueRootIndex);
__ Branch(&slow_case_, eq, result_, Operand(at));
__ bind(&exit_);
}
@ -3306,11 +3298,8 @@ void SubStringStub::Generate(MacroAssembler* masm) {
__ ld(a2, MemOperand(sp, kToOffset));
__ ld(a3, MemOperand(sp, kFromOffset));
// Does not needed?
// STATIC_ASSERT(kFromOffset == kToOffset + 4);
STATIC_ASSERT(kSmiTag == 0);
// Does not needed?
// STATIC_ASSERT(kSmiTagSize + kSmiShiftSize == 1);
// Utilize delay slots. SmiUntag doesn't emit a jump, everything else is
// safe in this case.
@ -3503,6 +3492,7 @@ void SubStringStub::Generate(MacroAssembler* masm) {
// a1: instance type
// a2: length
// a3: from index (untagged)
__ SmiTag(a3);
StringCharAtGenerator generator(v0, a3, a2, v0, &runtime, &runtime, &runtime,
STRING_INDEX_IS_NUMBER, RECEIVER_IS_STRING);
generator.GenerateFast(masm);