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[builtins] Avoid reloading undefined value in InterpreterEntryTrampoline

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Since we were already loading the undefined value a few lines above,
we could avoid loading it again.

Bug: v8:9771
Change-Id: Id05a77494c06a212612a365b5c0dcba4803ba756
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1817609
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63935}
This commit is contained in:
Santiago Aboy Solanes 2019-09-23 17:15:37 +01:00 committed by Commit Bot
parent 12a9ee3a5b
commit 40c0f84a38
3 changed files with 12 additions and 15 deletions
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7
src/builtins/arm/builtins-arm.cc
View File

@ -1138,11 +1138,11 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
// If ok, push undefined as the initial value for all register file entries.
Label loop_header;
Label loop_check;
__ LoadRoot(r9, RootIndex::kUndefinedValue);
__ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
__ b(&loop_check, al);
__ bind(&loop_header);
// TODO(rmcilroy): Consider doing more than one push per loop iteration.
__ push(r9);
__ push(kInterpreterAccumulatorRegister);
// Continue loop if not done.
__ bind(&loop_check);
__ sub(r4, r4, Operand(kPointerSize), SetCC);
@ -1157,8 +1157,7 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
__ cmp(r9, Operand::Zero());
__ str(r3, MemOperand(fp, r9, LSL, kPointerSizeLog2), ne);
// Load accumulator with undefined.
__ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
// The accumulator is already loaded with undefined.
// Load the dispatch table into a register and dispatch to the bytecode
// handler at the current bytecode offset.

7
src/builtins/arm64/builtins-arm64.cc
View File

@ -1270,13 +1270,13 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
// Note: there should always be at least one stack slot for the return
// register in the register file.
Label loop_header;
__ LoadRoot(x10, RootIndex::kUndefinedValue);
__ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
__ Lsr(x11, x11, kSystemPointerSizeLog2);
// Round up the number of registers to a multiple of 2, to align the stack
// to 16 bytes.
__ Add(x11, x11, 1);
__ Bic(x11, x11, 1);
__ PushMultipleTimes(x10, x11);
__ PushMultipleTimes(kInterpreterAccumulatorRegister, x11);
__ Bind(&loop_header);
}
@ -1291,8 +1291,7 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
__ Str(x3, MemOperand(fp, x10, LSL, kSystemPointerSizeLog2));
__ Bind(&no_incoming_new_target_or_generator_register);
// Load accumulator with undefined.
__ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
// The accumulator is already loaded with undefined.
// Load the dispatch table into a register and dispatch to the bytecode
// handler at the current bytecode offset.

13
src/builtins/x64/builtins-x64.cc
View File

@ -1154,11 +1154,11 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
// If ok, push undefined as the initial value for all register file entries.
Label loop_header;
Label loop_check;
__ LoadRoot(rax, RootIndex::kUndefinedValue);
__ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
__ j(always, &loop_check, Label::kNear);
__ bind(&loop_header);
// TODO(rmcilroy): Consider doing more than one push per loop iteration.
__ Push(rax);
__ Push(kInterpreterAccumulatorRegister);
// Continue loop if not done.
__ bind(&loop_check);
__ subq(rcx, Immediate(kSystemPointerSize));
@ -1169,16 +1169,15 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
// register, initialize it with incoming value which was passed in rdx.
Label no_incoming_new_target_or_generator_register;
__ movsxlq(
rax,
rcx,
FieldOperand(kInterpreterBytecodeArrayRegister,
BytecodeArray::kIncomingNewTargetOrGeneratorRegisterOffset));
__ testl(rax, rax);
__ testl(rcx, rcx);
__ j(zero, &no_incoming_new_target_or_generator_register, Label::kNear);
__ movq(Operand(rbp, rax, times_system_pointer_size, 0), rdx);
__ movq(Operand(rbp, rcx, times_system_pointer_size, 0), rdx);
__ bind(&no_incoming_new_target_or_generator_register);
// Load accumulator with undefined.
__ LoadRoot(kInterpreterAccumulatorRegister, RootIndex::kUndefinedValue);
// The accumulator is already loaded with undefined.
// Load the dispatch table into a register and dispatch to the bytecode
// handler at the current bytecode offset.