Index: compiler-rt/trunk/test/asan/TestCases/Linux/odr-violation.cc
===================================================================
--- compiler-rt/trunk/test/asan/TestCases/Linux/odr-violation.cc
+++ compiler-rt/trunk/test/asan/TestCases/Linux/odr-violation.cc
@@ -23,9 +23,14 @@
 // RUN: %env_asan_opts=fast_unwind_on_malloc=0:detect_odr_violation=2:suppressions=%t.supp      %run %t-ODR-EXE 2>&1 | FileCheck %s --check-prefix=DISABLED
 // RUN: rm -f %t.supp
 //
-// Use private aliases for global variables: use indicator symbol to detect ODR violation.
+// Use private aliases for global variables without indicator symbol.
 // RUN: %clangxx_asan -DBUILD_SO=1 -fPIC -shared -mllvm -asan-use-private-alias %s -o %t-ODR-SO.so -DSZ=100
 // RUN: %clangxx_asan -mllvm -asan-use-private-alias %s %t-ODR-SO.so -Wl,-R. -o %t-ODR-EXE
+// RUN: %env_asan_opts=fast_unwind_on_malloc=0 %run %t-ODR-EXE 2>&1 | FileCheck %s --check-prefix=DISABLED
+
+// Use private aliases for global variables: use indicator symbol to detect ODR violation.
+// RUN: %clangxx_asan -DBUILD_SO=1 -fPIC -shared -mllvm -asan-use-private-alias -mllvm -asan-use-odr-indicator  %s -o %t-ODR-SO.so -DSZ=100
+// RUN: %clangxx_asan -mllvm -asan-use-private-alias -mllvm -asan-use-odr-indicator %s %t-ODR-SO.so -Wl,-R. -o %t-ODR-EXE
 // RUN: %env_asan_opts=fast_unwind_on_malloc=0 not %run %t-ODR-EXE 2>&1 | FileCheck %s
 
 // GNU driver doesn't handle .so files properly.
Index: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -344,10 +344,14 @@
     cl::init(0));
 
 static cl::opt<bool>
-    ClUsePrivateAliasForGlobals("asan-use-private-alias",
-                                cl::desc("Use private aliases for global"
-                                         " variables"),
-                                cl::Hidden, cl::init(false));
+    ClUsePrivateAlias("asan-use-private-alias",
+                      cl::desc("Use private aliases for global variables"),
+                      cl::Hidden, cl::init(false));
+
+static cl::opt<bool>
+    ClUseOdrIndicator("asan-use-odr-indicator",
+                      cl::desc("Use odr indicators to improve ODR reporting"),
+                      cl::Hidden, cl::init(false));
 
 static cl::opt<bool>
     ClUseGlobalsGC("asan-globals-live-support",
@@ -2173,12 +2177,14 @@
     bool CanUsePrivateAliases =
         TargetTriple.isOSBinFormatELF() || TargetTriple.isOSBinFormatMachO() ||
         TargetTriple.isOSBinFormatWasm();
-    if (CanUsePrivateAliases && ClUsePrivateAliasForGlobals) {
+    if (CanUsePrivateAliases && ClUsePrivateAlias) {
       // Create local alias for NewGlobal to avoid crash on ODR between
       // instrumented and non-instrumented libraries.
-      auto *GA =
+      InstrumentedGlobal =
           GlobalAlias::create(GlobalValue::PrivateLinkage, "", NewGlobal);
+    }
 
+    if (ClUseOdrIndicator) {
       // With local aliases, we need to provide another externally visible
       // symbol __odr_asan_XXX to detect ODR violation.
       auto *ODRIndicatorSym =
@@ -2192,7 +2198,6 @@
       ODRIndicatorSym->setDLLStorageClass(NewGlobal->getDLLStorageClass());
       ODRIndicatorSym->setAlignment(1);
       ODRIndicator = ODRIndicatorSym;
-      InstrumentedGlobal = GA;
     }
 
     Constant *Initializer = ConstantStruct::get(
Index: llvm/trunk/test/Instrumentation/AddressSanitizer/local_alias.ll
===================================================================
--- llvm/trunk/test/Instrumentation/AddressSanitizer/local_alias.ll
+++ llvm/trunk/test/Instrumentation/AddressSanitizer/local_alias.ll
@@ -1,4 +1,7 @@
-; RUN: opt < %s -asan -asan-module -asan-use-private-alias=1 -S | FileCheck %s
+; RUN: opt < %s -asan -asan-module -S | FileCheck %s --check-prefixes=CHECK-NOALIAS,CHECK-NOINDICATOR
+; RUN: opt < %s -asan -asan-module -asan-use-private-alias=1 -S | FileCheck %s --check-prefixes=CHECK-ALIAS,CHECK-NOINDICATOR
+; RUN: opt < %s -asan -asan-module -asan-use-odr-indicator=1 -S | FileCheck %s --check-prefixes=CHECK-INDICATOR,CHECK-NOALIAS
+; RUN: opt < %s -asan -asan-module -asan-use-private-alias=1 -asan-use-odr-indicator=1 -S | FileCheck %s --check-prefixes=CHECK-ALIAS,CHECK-INDICATOR
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
@@ -6,8 +9,10 @@
 @a = internal global [2 x i32] zeroinitializer, align 4
 
 ; Check that we generate internal alias and odr indicator symbols for global to be protected.
-; CHECK: @__odr_asan_gen_a = internal global i8 0, align 1
-; CHECK: @0 = private alias { [2 x i32], [56 x i8] }, { [2 x i32], [56 x i8] }* @a
+; CHECK-NOINDICATOR-NOT: __odr_asan_gen_a
+; CHECK-NOALIAS-NOT: private alias
+; CHECK-INDICATOR: @__odr_asan_gen_a = internal global i8 0, align 1
+; CHECK-ALIAS: @0 = private alias { [2 x i32], [56 x i8] }, { [2 x i32], [56 x i8] }* @a
 
 ; Function Attrs: nounwind sanitize_address uwtable
 define i32 @foo(i32 %M) #0 {