msan, codegen, instcombine: Keep more lifetime markers used for msan

Reviewers: eugenis

Subscribers: hiraditya, cfe-commits, #sanitizers, llvm-commits

Tags: #clang, #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D66695

llvm-svn: 369979

2 files changed, 6 insertions, 11 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index d53fb46f336..0e04a514565 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -516,13 +516,12 @@ EmitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *M) {
 
       // Avoid creating a conditional cleanup just to hold an llvm.lifetime.end
       // marker. Instead, start the lifetime of a conditional temporary earlier
-      // so that it's unconditional. Don't do this in ASan's use-after-scope
-      // mode so that it gets the more precise lifetime marks. If the type has
-      // a non-trivial destructor, we'll have a cleanup block for it anyway,
-      // so this typically doesn't help; skip it in that case.
+      // so that it's unconditional. Don't do this with sanitizers which need
+      // more precise lifetime marks.
       ConditionalEvaluation *OldConditional = nullptr;
       CGBuilderTy::InsertPoint OldIP;
       if (isInConditionalBranch() && !E->getType().isDestructedType() &&
+          !SanOpts.has(SanitizerKind::Memory) &&
           !CGM.getCodeGenOpts().SanitizeAddressUseAfterScope) {
         OldConditional = OutermostConditional;
         OutermostConditional = nullptr;
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 95b8fdce783..228093044e1 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -47,13 +47,9 @@ static bool shouldEmitLifetimeMarkers(const CodeGenOptions &CGOpts,
   if (CGOpts.DisableLifetimeMarkers)
     return false;
 
-  // Disable lifetime markers in msan builds.
-  // FIXME: Remove this when msan works with lifetime markers.
-  if (LangOpts.Sanitize.has(SanitizerKind::Memory))
-    return false;
-
-  // Asan uses markers for use-after-scope checks.
-  if (CGOpts.SanitizeAddressUseAfterScope)
+  // Sanitizers may use markers.
+  if (CGOpts.SanitizeAddressUseAfterScope ||
+      LangOpts.Sanitize.has(SanitizerKind::Memory))
     return true;
 
   // For now, only in optimized builds.