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Bug 1916388 - Always initialize all fixed slots if bailAfter testing function is used. r=jonco

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Not adding the test case because it's a bit slow, hard to reduce, and likely
brittle too.

Differential Revision: https://phabricator.services.mozilla.com/D221130
This commit is contained in:
Jan de Mooij
2024-09-05 14:30:10 +00:00
parent 439fe4f9af
commit 2484655dec
1 changed files with 12 additions and 3 deletions
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15
js/src/jit/CodeGenerator.cpp
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@@ -8428,8 +8428,8 @@ void CodeGenerator::visitNewObjectVMCall(LNewObject* lir) {
restoreLive(lir); restoreLive(lir);
} }
static bool ShouldInitFixedSlots(LNewPlainObject* lir, const Shape* shape, static bool ShouldInitFixedSlots(MIRGenerator* gen, LNewPlainObject* lir,
uint32_t nfixed) { const Shape* shape, uint32_t nfixed) {
// Look for StoreFixedSlot instructions following an object allocation // Look for StoreFixedSlot instructions following an object allocation
// that write to this object before a GC is triggered or this object is // that write to this object before a GC is triggered or this object is
// passed to a VM call. If all fixed slots will be initialized, the // passed to a VM call. If all fixed slots will be initialized, the
@@ -8439,6 +8439,14 @@ static bool ShouldInitFixedSlots(LNewPlainObject* lir, const Shape* shape,
return false; return false;
} }
#ifdef DEBUG
// The bailAfter testing function can trigger a bailout between allocating the
// object and initializing the slots.
if (gen->options.ionBailAfterEnabled()) {
return true;
}
#endif
// Keep track of the fixed slots that are initialized. initializedSlots is // Keep track of the fixed slots that are initialized. initializedSlots is
// a bit mask with a bit for each slot. // a bit mask with a bit for each slot.
MOZ_ASSERT(nfixed <= NativeObject::MAX_FIXED_SLOTS); MOZ_ASSERT(nfixed <= NativeObject::MAX_FIXED_SLOTS);
@@ -8556,7 +8564,8 @@ void CodeGenerator::visitNewPlainObject(LNewPlainObject* lir) {
Imm32(int32_t(initialHeap))), Imm32(int32_t(initialHeap))),
StoreRegisterTo(objReg)); StoreRegisterTo(objReg));
bool initContents = ShouldInitFixedSlots(lir, shape, mir->numFixedSlots()); bool initContents =
ShouldInitFixedSlots(gen, lir, shape, mir->numFixedSlots());
masm.movePtr(ImmGCPtr(shape), shapeReg); masm.movePtr(ImmGCPtr(shape), shapeReg);
masm.createPlainGCObject( masm.createPlainGCObject(