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[msan] Fix select instrumentation.

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Select condition shadow was being ignored resulting in false negatives.
This change OR-s sign-extended condition shadow into the result shadow.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189785 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evgeniy Stepanov 2013-09-03 10:04:11 +00:00
parent fdb6a38913
commit 6a9b29ec9b
2 changed files with 15 additions and 3 deletions
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9
lib/Transforms/Instrumentation/MemorySanitizer.cpp
View File

@ -1743,9 +1743,12 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
void visitSelectInst(SelectInst& I) {
IRBuilder<> IRB(&I);
setShadow(&I, IRB.CreateSelect(I.getCondition(),
getShadow(I.getTrueValue()), getShadow(I.getFalseValue()),
"_msprop"));
// a = select b, c, d
// Sa = (sext Sb) | (select b, Sc, Sd)
Value *S = IRB.CreateSelect(I.getCondition(), getShadow(I.getTrueValue()),
getShadow(I.getFalseValue()));
Value *S2 = IRB.CreateSExt(getShadow(I.getCondition()), S->getType());
setShadow(&I, IRB.CreateOr(S, S2, "_msprop"));
if (MS.TrackOrigins) {
// Origins are always i32, so any vector conditions must be flattened.
// FIXME: consider tracking vector origins for app vectors?

9
test/Instrumentation/MemorySanitizer/msan_basic.ll
View File

@ -260,6 +260,8 @@ entry:
; CHECK: @Select
; CHECK: select
; CHECK-NEXT: sext i1 {{.*}} to i32
; CHECK-NEXT: or i32
; CHECK-NEXT: select
; CHECK: ret i32
@ -274,6 +276,13 @@ entry:
ret <8 x i16> %cond
}
; CHECK: @SelectVector
; CHECK: select <8 x i1>
; CHECK-NEXT: sext <8 x i1> {{.*}} to <8 x i16>
; CHECK-NEXT: or <8 x i16>
; CHECK-NEXT: select <8 x i1>
; CHECK: ret <8 x i16>
; CHECK-ORIGINS: @SelectVector
; CHECK-ORIGINS: bitcast <8 x i1> {{.*}} to i8
; CHECK-ORIGINS: icmp ne i8