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fix PR17635: false positive with packed structures

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LLVM optimizers may widen accesses to packed structures that overflow the structure itself, but should be in bounds up to the alignment of the object

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193317 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nuno Lopes 2013-10-24 09:17:24 +00:00
parent 2f21452ba1
commit 5e1d0d39db
4 changed files with 38 additions and 5 deletions
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3
include/llvm/Analysis/MemoryBuiltins.h
View File

@ -228,6 +228,7 @@ class ObjectSizeOffsetEvaluator
Value *Zero;
CacheMapTy CacheMap;
PtrSetTy SeenVals;
bool RoundToAlign;
SizeOffsetEvalType unknown() {
return std::make_pair((Value*)0, (Value*)0);
@ -236,7 +237,7 @@ class ObjectSizeOffsetEvaluator
public:
ObjectSizeOffsetEvaluator(const DataLayout *DL, const TargetLibraryInfo *TLI,
LLVMContext &Context);
LLVMContext &Context, bool RoundToAlign = false);
SizeOffsetEvalType compute(Value *V);
bool knownSize(SizeOffsetEvalType SizeOffset) {

8
lib/Analysis/MemoryBuiltins.cpp
View File

@ -588,8 +588,10 @@ SizeOffsetType ObjectSizeOffsetVisitor::visitInstruction(Instruction &I) {
ObjectSizeOffsetEvaluator::ObjectSizeOffsetEvaluator(const DataLayout *DL,
const TargetLibraryInfo *TLI,
LLVMContext &Context)
: DL(DL), TLI(TLI), Context(Context), Builder(Context, TargetFolder(DL)) {
LLVMContext &Context,
bool RoundToAlign)
: DL(DL), TLI(TLI), Context(Context), Builder(Context, TargetFolder(DL)),
RoundToAlign(RoundToAlign) {
IntTy = DL->getIntPtrType(Context);
Zero = ConstantInt::get(IntTy, 0);
}
@ -614,7 +616,7 @@ SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute(Value *V) {
}
SizeOffsetEvalType ObjectSizeOffsetEvaluator::compute_(Value *V) {
ObjectSizeOffsetVisitor Visitor(DL, TLI, Context);
ObjectSizeOffsetVisitor Visitor(DL, TLI, Context, RoundToAlign);
SizeOffsetType Const = Visitor.compute(V);
if (Visitor.bothKnown(Const))
return std::make_pair(ConstantInt::get(Context, Const.first),

3
lib/Transforms/Instrumentation/BoundsChecking.cpp
View File

@ -172,7 +172,8 @@ bool BoundsChecking::runOnFunction(Function &F) {
TrapBB = 0;
BuilderTy TheBuilder(F.getContext(), TargetFolder(TD));
Builder = &TheBuilder;
ObjectSizeOffsetEvaluator TheObjSizeEval(TD, TLI, F.getContext());
ObjectSizeOffsetEvaluator TheObjSizeEval(TD, TLI, F.getContext(),
/*RoundToAlign=*/true);
ObjSizeEval = &TheObjSizeEval;
// check HANDLE_MEMORY_INST in include/llvm/Instruction.def for memory

29
test/Instrumentation/BoundsChecking/simple-32.ll Normal file
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@ -0,0 +1,29 @@
; RUN: opt < %s -bounds-checking -S | FileCheck %s
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32-S128"
%struct.s2_packed = type <{ i64, i32, i32, i32, i16, i8 }>
; CHECK-LABEL: @f
; CHECK-NOT: trap
define i16 @f() {
entry:
%packed1 = alloca %struct.s2_packed, align 8
%gep = getelementptr inbounds %struct.s2_packed* %packed1, i32 0, i32 4
%ptr = bitcast i16* %gep to i32*
%val = load i32* %ptr, align 4
%valt = trunc i32 %val to i16
ret i16 %valt
}
; CHECK-LABEL: @f
; CHECK: call void @llvm.trap()
define i16 @f2() {
entry:
%packed1 = alloca %struct.s2_packed, align 8
%gep = getelementptr inbounds %struct.s2_packed* %packed1, i32 0, i32 4
%ptr = bitcast i16* %gep to i48*
%val = load i48* %ptr, align 4
%valt = trunc i48 %val to i16
ret i16 %valt
}