[asan] Don't check ODR violations for particular types of globals

Summary:
private and internal: should not trigger ODR at all.
unnamed_addr: current ODR checking approach fail and rereport false violation if
a linker merges such globals
linkonce_odr, weak_odr: could cause similar problems and they are already not
instrumented for ELF.

Reviewers: eugenis, kcc

Subscribers: kubamracek, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D55621

llvm-svn: 349015

1 files changed, 7 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index cd7652d3c3a..87288388853 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -2190,7 +2190,13 @@ bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M, bool
           GlobalAlias::create(GlobalValue::PrivateLinkage, "", NewGlobal);
     }
 
-    if (UseOdrIndicator) {
+    // ODR check is not useful for the following, but we see false reports
+    // caused by linker optimizations.
+    if (NewGlobal->hasLocalLinkage() || NewGlobal->hasGlobalUnnamedAddr() ||
+        NewGlobal->hasLinkOnceODRLinkage() || NewGlobal->hasWeakODRLinkage()) {
+      ODRIndicator = ConstantExpr::getIntToPtr(ConstantInt::get(IntptrTy, -1),
+                                               IRB.getInt8PtrTy());
+    } else if (UseOdrIndicator) {
       // With local aliases, we need to provide another externally visible
       // symbol __odr_asan_XXX to detect ODR violation.
       auto *ODRIndicatorSym =