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[maglev][arm64] Fix scratch register shortage on funs with many args

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The Sub macro sometimes needs a scratch register when the 2nd operand
is too large to be encoded in the instruction. The prologue was
already reserving 2 scratch registers, which made Sub crash on a
DCHECK when trying to reserve one more scratch register.

Bug: v8:7700
Change-Id: I995689b8b16e3ef216641f0b6cadbf58f7f3740b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4128554
Commit-Queue: Darius Mercadier <dmercadier@chromium.org>
Reviewed-by: Jakob Linke <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#85029}
This commit is contained in:
Darius M 2022-12-28 14:19:01 +01:00 committed by V8 LUCI CQ
parent b8b136cb36
commit 0f3036ce09
2 changed files with 47 additions and 1 deletions
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2
src/maglev/arm64/maglev-assembler-arm64.cc
View File

@ -235,7 +235,6 @@ void MaglevAssembler::Prologue(Graph* graph) {
// after building the frame we can quickly precheck both at once.
UseScratchRegisterScope temps(this);
Register stack_slots_size = temps.AcquireX();
Register interrupt_stack_limit = temps.AcquireX();
Mov(stack_slots_size, fp);
// Round up the stack slots and max call args separately, since both will be
// padded by their respective uses.
@ -245,6 +244,7 @@ void MaglevAssembler::Prologue(Graph* graph) {
std::max(static_cast<int>(graph->max_deopted_stack_size()),
max_stack_slots_used * kSystemPointerSize);
Sub(stack_slots_size, stack_slots_size, Immediate(max_stack_size));
Register interrupt_stack_limit = temps.AcquireX();
LoadStackLimit(interrupt_stack_limit, StackLimitKind::kInterruptStackLimit);
Cmp(stack_slots_size, interrupt_stack_limit);

46
test/mjsunit/maglev/lots-of-args.js Normal file
View File

@ -0,0 +1,46 @@
// Copyright 2022 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.
// Flags: --allow-natives-syntax --maglev
function foo(
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x,
x, x, x, x, x, x, x, x, x, x, x, x, x, x, x, x
) { }
%PrepareFunctionForOptimization(foo);
foo();
foo();
%OptimizeMaglevOnNextCall(foo);
foo();