[msan] Fix handling of phi in blacklisted functions.

llvm-svn: 212454

diff --git a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index 9b595d8..496ab48 100644 (file)
--- a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -716,8 +716,6 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
 
     // Finalize PHI nodes.
     for (PHINode *PN : ShadowPHINodes) {
-      Value *S = getShadow(PN);
-      if (isa<Constant>(S)) continue;
       PHINode *PNS = cast<PHINode>(getShadow(PN));
       PHINode *PNO = MS.TrackOrigins ? cast<PHINode>(getOrigin(PN)) : nullptr;
       size_t NumValues = PN->getNumIncomingValues();
@@ -2396,6 +2394,11 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
 
   void visitPHINode(PHINode &I) {
     IRBuilder<> IRB(&I);
+    if (!PropagateShadow) {
+      setShadow(&I, getCleanShadow(&I));
+      return;
+    }
+
     ShadowPHINodes.push_back(&I);
     setShadow(&I, IRB.CreatePHI(getShadowTy(&I), I.getNumIncomingValues(),
                                 "_msphi_s"));

diff --git a/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll b/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
index 5814f78..51693cd 100644 (file)
--- a/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
+++ b/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
@@ -743,6 +743,29 @@ declare i32 @NoSanitizeMemoryUndefHelper(i32 %x)
 ; CHECK: ret i32
 
 
+; Test PHINode instrumentation in blacklisted functions
+
+define i32 @NoSanitizeMemoryPHI(i32 %x) {
+entry:
+  %tobool = icmp ne i32 %x, 0
+  br i1 %tobool, label %cond.true, label %cond.false
+
+cond.true:                                        ; preds = %entry
+  br label %cond.end
+
+cond.false:                                       ; preds = %entry
+  br label %cond.end
+
+cond.end:                                         ; preds = %cond.false, %cond.true
+  %cond = phi i32 [ undef, %cond.true ], [ undef, %cond.false ]
+  ret i32 %cond
+}
+
+; CHECK: [[A:%.*]] = phi i32 [ undef, %cond.true ], [ undef, %cond.false ]
+; CHECK: store i32 0, i32* bitcast {{.*}} @__msan_retval_tls
+; CHECK: ret i32 [[A]]
+
+
 ; Test argument shadow alignment
 
 define <2 x i64> @ArgumentShadowAlignment(i64 %a, <2 x i64> %b) sanitize_memory {