MemoryBuiltins: Properly guard ObjectSizeOffsetVisitor against cycles in the IR.
The previous fix only checked for simple cycles, use a set to catch longer
cycles too.
Drop the broken check from the ObjectSizeOffsetEvaluator. The BoundsChecking
pass doesn't have to deal with invalid IR like InstCombine does.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162120 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/MemoryBuiltins.cpp b/lib/Analysis/MemoryBuiltins.cpp
index e77d2ff..b986b32 100644
--- a/lib/Analysis/MemoryBuiltins.cpp
+++ b/lib/Analysis/MemoryBuiltins.cpp
@@ -358,11 +358,16 @@
SizeOffsetType ObjectSizeOffsetVisitor::compute(Value *V) {
V = V->stripPointerCasts();
+ if (Instruction *I = dyn_cast<Instruction>(V)) {
+ // If we have already seen this instruction, bail out. Cycles can happen in
+ // unreachable code after constant propagation.
+ if (!SeenInsts.insert(I))
+ return unknown();
- if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
- return visitGEPOperator(*GEP);
- if (Instruction *I = dyn_cast<Instruction>(V))
+ if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
+ return visitGEPOperator(*GEP);
return visit(*I);
+ }
if (Argument *A = dyn_cast<Argument>(V))
return visitArgument(*A);
if (ConstantPointerNull *P = dyn_cast<ConstantPointerNull>(V))
@@ -371,9 +376,12 @@
return visitGlobalVariable(*GV);
if (UndefValue *UV = dyn_cast<UndefValue>(V))
return visitUndefValue(*UV);
- if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
if (CE->getOpcode() == Instruction::IntToPtr)
return unknown(); // clueless
+ if (CE->getOpcode() == Instruction::GetElementPtr)
+ return visitGEPOperator(cast<GEPOperator>(*CE));
+ }
DEBUG(dbgs() << "ObjectSizeOffsetVisitor::compute() unhandled value: " << *V
<< '\n');
@@ -473,10 +481,6 @@
}
SizeOffsetType ObjectSizeOffsetVisitor::visitGEPOperator(GEPOperator &GEP) {
- // Ignore self-referencing GEPs, they can occur in unreachable code.
- if (&GEP == GEP.getPointerOperand())
- return unknown();
-
SizeOffsetType PtrData = compute(GEP.getPointerOperand());
if (!bothKnown(PtrData) || !GEP.hasAllConstantIndices())
return unknown();
@@ -510,10 +514,6 @@
}
SizeOffsetType ObjectSizeOffsetVisitor::visitSelectInst(SelectInst &I) {
- // ignore malformed self-looping selects
- if (I.getTrueValue() == &I || I.getFalseValue() == &I)
- return unknown();
-
SizeOffsetType TrueSide = compute(I.getTrueValue());
SizeOffsetType FalseSide = compute(I.getFalseValue());
if (bothKnown(TrueSide) && bothKnown(FalseSide) && TrueSide == FalseSide)
@@ -533,8 +533,7 @@
ObjectSizeOffsetEvaluator::ObjectSizeOffsetEvaluator(const TargetData *TD,
LLVMContext &Context)
-: TD(TD), Context(Context), Builder(Context, TargetFolder(TD)),
-Visitor(TD, Context) {
+: TD(TD), Context(Context), Builder(Context, TargetFolder(TD)) {
IntTy = TD->getIntPtrType(Context);
Zero = ConstantInt::get(IntTy, 0);
}
@@ -559,6 +558,7 @@
}
SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) {
+ ObjectSizeOffsetVisitor Visitor(TD, Context);
SizeOffsetType Const = Visitor.compute(V);
if (Visitor.bothKnown(Const))
return std::make_pair(ConstantInt::get(Context, Const.first),
@@ -719,10 +719,6 @@
}
SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitSelectInst(SelectInst &I) {
- // ignore malformed self-looping selects
- if (I.getTrueValue() == &I || I.getFalseValue() == &I)
- return unknown();
-
SizeOffsetEvalType TrueSide = compute_(I.getTrueValue());
SizeOffsetEvalType FalseSide = compute_(I.getFalseValue());