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Enhance analysis passes so that they apply the same analysis to malloc calls as to MallocInst.

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Reviewed by Eli Friedman.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82281 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Victor Hernandez
2009-09-18 21:34:51 +00:00
parent d268e00938
commit 46e8312fb7
5 changed files with 50 additions and 12 deletions
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lib/Analysis/BasicAliasAnalysis.cpp
+11 -3
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@@ -15,6 +15,7 @@
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/MallocHelper.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
@@ -102,7 +103,7 @@ static bool isNonEscapingLocalObject(const Value *V) {
/// isObjectSmallerThan - Return true if we can prove that the object specified
/// by V is smaller than Size.
static bool isObjectSmallerThan(const Value *V, unsigned Size,
const TargetData &TD) {
LLVMContext &Context, const TargetData &TD) {
const Type *AccessTy;
if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
AccessTy = GV->getType()->getElementType();
@@ -111,6 +112,12 @@ static bool isObjectSmallerThan(const Value *V, unsigned Size,
AccessTy = AI->getType()->getElementType();
else
return false;
} else if (const CallInst* CI = extractMallocCall(V)) {
if (!isArrayMalloc(V, Context, &TD))
// The size is the argument to the malloc call.
if (const ConstantInt* C = dyn_cast<ConstantInt>(CI->getOperand(1)))
return (C->getZExtValue() < Size);
return false;
} else if (const Argument *A = dyn_cast<Argument>(V)) {
if (A->hasByValAttr())
AccessTy = cast<PointerType>(A->getType())->getElementType();
@@ -340,9 +347,10 @@ BasicAliasAnalysis::alias(const Value *V1, unsigned V1Size,
// If the size of one access is larger than the entire object on the other
// side, then we know such behavior is undefined and can assume no alias.
LLVMContext &Context = V1->getContext();
if (TD)
if ((V1Size != ~0U && isObjectSmallerThan(O2, V1Size, *TD)) ||
(V2Size != ~0U && isObjectSmallerThan(O1, V2Size, *TD)))
if ((V1Size != ~0U && isObjectSmallerThan(O2, V1Size, Context, *TD)) ||
(V2Size != ~0U && isObjectSmallerThan(O1, V2Size, Context, *TD)))
return NoAlias;
// If one pointer is the result of a call/invoke and the other is a