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[maglev][arm64] Fix some alignment issues with stack slot count

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We make sure the number of stack slots in the graph will yield
an aligned stack in the prologue.

We also guarantee the number of extra slots used in a safepoint is
even.

Bug: v8:7700
Change-Id: Ib59fdc5e81dc8f0cf97b7122346cb2decbc58609
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4079164
Auto-Submit: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Darius Mercadier <dmercadier@chromium.org>
Cr-Commit-Position: refs/heads/main@{#84667}
This commit is contained in:
Victor Gomes 2022-12-05 18:56:43 +01:00 committed by V8 LUCI CQ
parent d0d6ed66fd
commit acfc169b0c
4 changed files with 21 additions and 13 deletions
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7
src/maglev/arm64/maglev-assembler-arm64.cc
View File

@ -64,10 +64,10 @@ void MaglevAssembler::Prologue(Graph* graph) {
// that could clobber these registers.
// Push the context and the JSFunction.
Push(kContextRegister, kJSFunctionRegister);
// Push the actual argument count a _possible_ stack slot.
// Push the actual argument count and a _possible_ stack slot.
Push(kJavaScriptCallArgCountRegister, xzr);
int remaining_stack_slots = code_gen_state()->stack_slots() - 1;
DCHECK_GE(remaining_stack_slots, 0);
{
ASM_CODE_COMMENT_STRING(this, " Stack/interrupt check");
// Stack check. This folds the checks for both the interrupt stack limit
@ -103,8 +103,7 @@ void MaglevAssembler::Prologue(Graph* graph) {
__ PopAll(RegisterInput::kAllowedRegisters);
__ B(*done);
},
deferred_call_stack_guard_return,
remaining_stack_slots > 0 ? remaining_stack_slots : 0);
deferred_call_stack_guard_return, remaining_stack_slots);
bind(*deferred_call_stack_guard_return);
}

6
src/maglev/maglev-assembler.h
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@ -213,7 +213,13 @@ class SaveRegisterStateForCall {
}
pushed_reg_index++;
}
#ifdef V8_TARGET_ARCH_ARM64
pushed_reg_index = RoundUp<2>(pushed_reg_index);
#endif
int num_pushed_double_reg = snapshot_.live_double_registers.Count();
#ifdef V8_TARGET_ARCH_ARM64
num_pushed_double_reg = RoundUp<2>(num_pushed_double_reg);
#endif
safepoint.SetNumPushedRegisters(pushed_reg_index + num_pushed_double_reg);
return safepoint;
}

7
src/maglev/maglev-code-generator.h
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@ -40,14 +40,7 @@ class MaglevCodeGenerator final {
int stack_slot_count() const { return code_gen_state_.stack_slots(); }
int stack_slot_count_with_fixed_frame() const {
// TODO(victorgomes): Find a better solution for this instead of ifdeffing
// the arch.
#ifdef V8_TARGET_ARCH_ARM64
return RoundUp(stack_slot_count() + StandardFrameConstants::kFixedSlotCount,
2);
#else
return stack_slot_count() + StandardFrameConstants::kFixedSlotCount;
#endif
}
MaglevAssembler* masm() { return &masm_; }

14
src/maglev/maglev-regalloc.cc
View File

@ -171,8 +171,18 @@ StraightForwardRegisterAllocator::StraightForwardRegisterAllocator(
: compilation_info_(compilation_info), graph_(graph) {
ComputePostDominatingHoles();
AllocateRegisters();
graph_->set_tagged_stack_slots(tagged_.top);
graph_->set_untagged_stack_slots(untagged_.top);
uint32_t tagged_stack_slots = tagged_.top;
uint32_t untagged_stack_slots = untagged_.top;
#ifdef V8_TARGET_ARCH_ARM64
// Due to alignment constraints, we add one untagged slot if
// stack_slots + fixed_slot_count is odd.
static_assert(StandardFrameConstants::kFixedSlotCount % 2 == 1);
if ((tagged_stack_slots + untagged_stack_slots) % 2 == 0) {
untagged_stack_slots++;
}
#endif // V8_TARGET_ARCH_ARM64
graph_->set_tagged_stack_slots(tagged_stack_slots);
graph_->set_untagged_stack_slots(untagged_stack_slots);
}
StraightForwardRegisterAllocator::~StraightForwardRegisterAllocator() = default;