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Revert "Remove all custom CopyCharsUnsigned implementations"
This reverts commit 5d8c489. Reason for revert: Fails on UBSan bot: https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20UBSan/7946 Original change's description: > Remove all custom CopyCharsUnsigned implementations > > It's unclear whether the custom implementation have any advantage over > the standard library one's. > Since we update our toolchain and standard library regularly, it might > well be the case that the custom implementations are slower by now. > > Thus this CL removes all {CopyCharsUnsigned} implementations and > implements {CopyChars} generically using {std::copy_n}. > > Note that this does not touch the {MemMove} and {MemCopy} functions > yet, as we have seen regressions when trying to remove them before > (https://crbug.com/v8/8675#c5). > > R=​leszeks@chromium.org > > Bug: v8:9396 > Change-Id: I97a183afebcccd2fbb567bdba02e827331475608 > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1800577 > Commit-Queue: Clemens Hammacher <clemensh@chromium.org> > Reviewed-by: Leszek Swirski <leszeks@chromium.org> > Cr-Commit-Position: refs/heads/master@{#63808} TBR=leszeks@chromium.org,clemensh@chromium.org Change-Id: Ia16da942c7c28ba71076d1e3b0b8a6388a4ba359 No-Presubmit: true No-Tree-Checks: true No-Try: true Bug: v8:9396 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1806103 Reviewed-by: Adam Klein <adamk@chromium.org> Commit-Queue: Adam Klein <adamk@chromium.org> Cr-Commit-Position: refs/heads/master@{#63810}
1 parent c9fa0c5 commit 0aac347

6 files changed

Lines changed: 374 additions & 31 deletions

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‎src/builtins/arm/builtins-arm.cc‎

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@@ -3167,6 +3167,51 @@ void Builtins::Generate_MemCopyUint8Uint8(MacroAssembler* masm) {
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__ Ret();
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}
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void Builtins::Generate_MemCopyUint16Uint8(MacroAssembler* masm) {
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Register dest = r0;
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Register src = r1;
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Register chars = r2;
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{
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UseScratchRegisterScope temps(masm);
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Register temp1 = r3;
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Register temp2 = temps.Acquire();
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Register temp3 = lr;
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Register temp4 = r4;
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Label loop;
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Label not_two;
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__ Push(lr, r4);
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__ bic(temp2, chars, Operand(0x3));
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__ add(temp2, dest, Operand(temp2, LSL, 1));
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__ bind(&loop);
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__ ldr(temp1, MemOperand(src, 4, PostIndex));
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__ uxtb16(temp3, temp1);
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__ uxtb16(temp4, temp1, 8);
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__ pkhbt(temp1, temp3, Operand(temp4, LSL, 16));
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__ str(temp1, MemOperand(dest));
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__ pkhtb(temp1, temp4, Operand(temp3, ASR, 16));
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__ str(temp1, MemOperand(dest, 4));
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__ add(dest, dest, Operand(8));
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__ cmp(dest, temp2);
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__ b(&loop, ne);
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__ mov(chars, Operand(chars, LSL, 31), SetCC); // bit0 => ne, bit1 => cs
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__ b(&not_two, cc);
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__ ldrh(temp1, MemOperand(src, 2, PostIndex));
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__ uxtb(temp3, temp1, 8);
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__ mov(temp3, Operand(temp3, LSL, 16));
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__ uxtab(temp3, temp3, temp1);
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__ str(temp3, MemOperand(dest, 4, PostIndex));
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__ bind(&not_two);
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__ ldrb(temp1, MemOperand(src), ne);
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__ strh(temp1, MemOperand(dest), ne);
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__ Pop(pc, r4);
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}
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}
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#undef __
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} // namespace internal

‎src/builtins/builtins-definitions.h‎

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Original file line numberDiff line numberDiff line change
@@ -1113,6 +1113,7 @@ namespace internal {
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TFS(SetProperty, kReceiver, kKey, kValue) \
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TFS(SetPropertyInLiteral, kReceiver, kKey, kValue) \
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ASM(MemCopyUint8Uint8, CCall) \
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ASM(MemCopyUint16Uint8, CCall) \
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ASM(MemMove, CCall) \
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\
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/* Trace */ \

‎src/builtins/builtins-internal-gen.cc‎

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Original file line numberDiff line numberDiff line change
@@ -933,6 +933,12 @@ void Builtins::Generate_MemCopyUint8Uint8(MacroAssembler* masm) {
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}
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#endif // !defined(V8_TARGET_ARCH_ARM) && !defined(V8_TARGET_ARCH_MIPS)
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#ifndef V8_TARGET_ARCH_ARM
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void Builtins::Generate_MemCopyUint16Uint8(MacroAssembler* masm) {
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masm->Call(BUILTIN_CODE(masm->isolate(), Illegal), RelocInfo::CODE_TARGET);
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}
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#endif // V8_TARGET_ARCH_ARM
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#ifndef V8_TARGET_ARCH_IA32
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void Builtins::Generate_MemMove(MacroAssembler* masm) {
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masm->Call(BUILTIN_CODE(masm->isolate(), Illegal), RelocInfo::CODE_TARGET);

‎src/parsing/scanner-character-streams.cc‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -265,7 +265,7 @@ class BufferedCharacterStream : public Utf16CharacterStream {
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}
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size_t length = Min(kBufferSize, range.length());
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i::CopyChars(buffer_, range.start, length);
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i::CopyCharsUnsigned(buffer_, range.start, length);
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buffer_end_ = &buffer_[length];
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return true;
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}

‎src/utils/memcopy.cc‎

Lines changed: 13 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -25,8 +25,18 @@ V8_EXPORT_PRIVATE void MemMove(void* dest, const void* src, size_t size) {
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(*memmove_function)(dest, src, size);
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}
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#elif V8_OS_POSIX && V8_HOST_ARCH_ARM
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void MemCopyUint16Uint8Wrapper(uint16_t* dest, const uint8_t* src,
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size_t chars) {
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uint16_t* limit = dest + chars;
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while (dest < limit) {
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*dest++ = static_cast<uint16_t>(*src++);
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}
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}
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V8_EXPORT_PRIVATE MemCopyUint8Function memcopy_uint8_function =
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&MemCopyUint8Wrapper;
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MemCopyUint16Uint8Function memcopy_uint16_uint8_function =
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&MemCopyUint16Uint8Wrapper;
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#elif V8_OS_POSIX && V8_HOST_ARCH_MIPS
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V8_EXPORT_PRIVATE MemCopyUint8Function memcopy_uint8_function =
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&MemCopyUint8Wrapper;
@@ -44,6 +54,9 @@ void init_memcopy_functions() {
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EmbeddedData d = EmbeddedData::FromBlob();
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memcopy_uint8_function = reinterpret_cast<MemCopyUint8Function>(
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d.InstructionStartOfBuiltin(Builtins::kMemCopyUint8Uint8));
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memcopy_uint16_uint8_function =
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reinterpret_cast<MemCopyUint16Uint8Function>(
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d.InstructionStartOfBuiltin(Builtins::kMemCopyUint16Uint8));
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}
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#elif V8_OS_POSIX && V8_HOST_ARCH_MIPS
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if (Isolate::CurrentEmbeddedBlobIsBinaryEmbedded()) {

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