[MSan] Disable sanitization for __sanitizer_dtor_callback.

Summary:
Eliminate unnecessary instrumentation at __sanitizer_dtor_callback
call sites.  Fixes https://github.com/google/sanitizers/issues/861.

Reviewers: eugenis, kcc

Reviewed By: eugenis

Subscribers: vitalybuka, llvm-commits, cfe-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D38063

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313831 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/lib/Transforms/Instrumentation/MemorySanitizer.cpp
index b7c6271869cd58819f6a576e512cc3f64b02474d..3b33ced2640ca545fecb305633bc41f5cca3c60d 100644 (file)
--- a/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -2588,6 +2588,7 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
 
   void visitCallSite(CallSite CS) {
     Instruction &I = *CS.getInstruction();
+    if (I.getMetadata("nosanitize")) return;
     assert((CS.isCall() || CS.isInvoke()) && "Unknown type of CallSite");
     if (CS.isCall()) {
       CallInst *Call = cast<CallInst>(&I);

diff --git a/test/Instrumentation/MemorySanitizer/call-nosanitize.ll b/test/Instrumentation/MemorySanitizer/call-nosanitize.ll
new file mode 100644 (file)
index 0000000..b5e6937
--- /dev/null
+++ b/test/Instrumentation/MemorySanitizer/call-nosanitize.ll
@@ -0,0 +1,16 @@
+; Verify that calls with !nosanitize are not instrumented by MSan.
+; RUN: opt < %s -msan -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @bar(i32 %x)
+
+define void @foo() {
+  call void @bar(i32 7), !nosanitize !{}
+  ret void
+}
+
+; CHECK-LABEL: define void @foo
+; CHECK-NOT: store i{{[0-9]+}} 0, {{.*}} @__msan_param_tls
+; CHECK: call void @bar
+; CHECK: ret void