Merging r229352:
------------------------------------------------------------------------
r229352 | david.majnemer | 2015-02-15 23:02:09 -0500 (Sun, 15 Feb 2015) | 9 lines
IR: Properly return nullptr when getAggregateElement is out-of-bounds
We didn't properly handle the out-of-bounds case for
ConstantAggregateZero and UndefValue. This would manifest as a crash
when the constant folder was asked to fold a load of a constant global
whose struct type has no operands.
This fixes PR22595.
------------------------------------------------------------------------
git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_35@232512 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/IR/Constants.h b/include/llvm/IR/Constants.h
index 0e72f04..3cf31c4 100644
--- a/include/llvm/IR/Constants.h
+++ b/include/llvm/IR/Constants.h
@@ -326,6 +326,9 @@
/// index.
Constant *getElementValue(unsigned Idx) const;
+ /// \brief Return the number of elements in the array, vector, or struct.
+ unsigned getNumElements() const;
+
/// Methods for support type inquiry through isa, cast, and dyn_cast:
///
static bool classof(const Value *V) {
@@ -1164,6 +1167,9 @@
/// index.
UndefValue *getElementValue(unsigned Idx) const;
+ /// \brief Return the number of elements in the array, vector, or struct.
+ unsigned getNumElements() const;
+
void destroyConstant() override;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
diff --git a/lib/IR/Constants.cpp b/lib/IR/Constants.cpp
index b815936..7557886 100644
--- a/lib/IR/Constants.cpp
+++ b/lib/IR/Constants.cpp
@@ -212,11 +212,11 @@
if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
return Elt < CV->getNumOperands() ? CV->getOperand(Elt) : nullptr;
- if (const ConstantAggregateZero *CAZ =dyn_cast<ConstantAggregateZero>(this))
- return CAZ->getElementValue(Elt);
+ if (const ConstantAggregateZero *CAZ = dyn_cast<ConstantAggregateZero>(this))
+ return Elt < CAZ->getNumElements() ? CAZ->getElementValue(Elt) : nullptr;
if (const UndefValue *UV = dyn_cast<UndefValue>(this))
- return UV->getElementValue(Elt);
+ return Elt < UV->getNumElements() ? UV->getElementValue(Elt) : nullptr;
if (const ConstantDataSequential *CDS =dyn_cast<ConstantDataSequential>(this))
return Elt < CDS->getNumElements() ? CDS->getElementAsConstant(Elt)
@@ -721,6 +721,14 @@
return getStructElement(Idx);
}
+unsigned ConstantAggregateZero::getNumElements() const {
+ const Type *Ty = getType();
+ if (const auto *AT = dyn_cast<ArrayType>(Ty))
+ return AT->getNumElements();
+ if (const auto *VT = dyn_cast<VectorType>(Ty))
+ return VT->getNumElements();
+ return Ty->getStructNumElements();
+}
//===----------------------------------------------------------------------===//
// UndefValue Implementation
@@ -754,7 +762,14 @@
return getStructElement(Idx);
}
-
+unsigned UndefValue::getNumElements() const {
+ const Type *Ty = getType();
+ if (const auto *AT = dyn_cast<ArrayType>(Ty))
+ return AT->getNumElements();
+ if (const auto *VT = dyn_cast<VectorType>(Ty))
+ return VT->getNumElements();
+ return Ty->getStructNumElements();
+}
//===----------------------------------------------------------------------===//
// ConstantXXX Classes
diff --git a/test/Transforms/InstSimplify/load.ll b/test/Transforms/InstSimplify/load.ll
new file mode 100644
index 0000000..92953cd
--- /dev/null
+++ b/test/Transforms/InstSimplify/load.ll
@@ -0,0 +1,19 @@
+; RUN: opt < %s -instsimplify -S | FileCheck %s
+
+@zeroinit = constant {} zeroinitializer
+@undef = constant {} undef
+
+define i32 @crash_on_zeroinit() {
+; CHECK-LABEL: @crash_on_zeroinit
+; CHECK: ret i32 0
+ %load = load i32* bitcast ({}* @zeroinit to i32*)
+ ret i32 %load
+}
+
+define i32 @crash_on_undef() {
+; CHECK-LABEL: @crash_on_undef
+; CHECK: ret i32 undef
+ %load = load i32* bitcast ({}* @undef to i32*)
+ ret i32 %load
+}
+
