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[JSC] IRO's ArithAbs transform can pin freed range bound proofs (cherry-pick WebKit/WebKit#72679) #530

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Merged
sosukesuzuki merged 1 commit into from
Aug 28, 2026
Merged

[JSC] IRO's ArithAbs transform can pin freed range bound proofs (cherry-pick WebKit/WebKit#72679) #530

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19 changes: 19 additions & 0 deletions JSTests/stress/dfg-integer-range-optimization-arith-abs-proof-use-after-free.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,19 @@
//@ runDefault("--useConcurrentJIT=0", "--thresholdForOptimizeAfterWarmUp=100", "--thresholdForFTLOptimizeAfterWarmUp=1000")

function foo(a, b) {
var r = 0;
var w = a | 0;
if (w === 0) {
var x = w - 3;
if (b)
r = Math.abs(x);
}
return r;
}
noInline(foo);

for (var i = 0; i < testLoopCount; ++i) {
var result = foo(0, 1);
if (result !== 3)
throw new Error("bad result at i=" + i + ": " + result);
}
15 changes: 8 additions & 7 deletions Source/JavaScriptCore/dfg/DFGIntegerRangeOptimizationPhase.cpp
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Expand Up @@ -1023,7 +1023,8 @@ class IntegerRangeOptimizationPhase : public Phase {

struct RangeBound {
int32_t value;
const Relationship* proof { nullptr };
Node* proofLeft { nullptr };
Node* proofRight { nullptr };
};

std::optional<std::tuple<RangeBound, RangeBound>> NODELETE rangeFor(Node* node)
Expand All @@ -1043,12 +1044,14 @@ class IntegerRangeOptimizationPhase : public Phase {
int32_t candidateMin = relationship.minValueOfLeft();
if (candidateMin > minBound.value) {
minBound.value = candidateMin;
minBound.proof = &relationship;
minBound.proofLeft = relationship.left().node();
minBound.proofRight = relationship.right().node();
}
int32_t candidateMax = relationship.maxValueOfLeft();
if (candidateMax < maxBound.value) {
maxBound.value = candidateMax;
maxBound.proof = &relationship;
maxBound.proofLeft = relationship.left().node();
maxBound.proofRight = relationship.right().node();
}
}
return std::tuple { minBound, maxBound };
Expand All @@ -1071,11 +1074,9 @@ class IntegerRangeOptimizationPhase : public Phase {

void pinRangeBoundProof(const RangeBound& bound)
{
if (!bound.proof)
return;
if (Node* right = bound.proof->right().node(); right && !right->isConstant())
if (Node* right = bound.proofRight; right && !right->isConstant())
right->mergeFlags(NodeMustGenerate);
if (Node* left = bound.proof->left().node(); left && !left->isConstant())
if (Node* left = bound.proofLeft; left && !left->isConstant())
left->mergeFlags(NodeMustGenerate);
}

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