From 6a9b29ec9b42e792732659e510a655449a41b661 Mon Sep 17 00:00:00 2001 From: Evgeniy Stepanov Date: Tue, 3 Sep 2013 10:04:11 +0000 Subject: [msan] Fix select instrumentation. 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 --- lib/Transforms/Instrumentation/MemorySanitizer.cpp | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/lib/Transforms/Instrumentation/MemorySanitizer.cpp index ae73a2e..f2cf7a7 100644 --- a/lib/Transforms/Instrumentation/MemorySanitizer.cpp +++ b/lib/Transforms/Instrumentation/MemorySanitizer.cpp @@ -1743,9 +1743,12 @@ struct MemorySanitizerVisitor : public InstVisitor { 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? -- cgit v1.1