5 files changed, 12 insertions, 9 deletions
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_flags.cc b/compiler-rt/lib/sanitizer_common/sanitizer_flags.cc
index 881cc3e7faa..8482751ecae 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_flags.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_flags.cc
@@ -20,6 +20,7 @@
 namespace __sanitizer {
 
 CommonFlags common_flags_dont_use;
+bool common_flags_defaults_set = false;
 
 struct FlagDescription {
   const char *name;
@@ -35,6 +36,11 @@ IntrusiveList<FlagDescription> flag_descriptions;
 #endif
 
 void SetCommonFlagsDefaults(CommonFlags *f) {
+  CHECK_EQ(common_flags(), f);
+  if (common_flags_defaults_set)
+    return;
+  common_flags_defaults_set = true;
+
   f->symbolize = true;
   f->external_symbolizer_path = 0;
   f->allow_addr2line = false;
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_flags.h b/compiler-rt/lib/sanitizer_common/sanitizer_flags.h
index 97641a6c49f..256ca8ce847 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_flags.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_flags.h
@@ -67,7 +67,10 @@ inline CommonFlags *common_flags() {
   return &common_flags_dont_use;
 }
 
+// Sets default values for common flags. If called multiple times,
+// sets default values only once.
 void SetCommonFlagsDefaults(CommonFlags *f);
+
 void ParseCommonFlagsFromString(CommonFlags *f, const char *str);
 void PrintFlagDescriptions();
 
diff --git a/compiler-rt/lib/ubsan/ubsan_flags.cc b/compiler-rt/lib/ubsan/ubsan_flags.cc
index 843f9a6c591..ae15fd389b1 100644
--- a/compiler-rt/lib/ubsan/ubsan_flags.cc
+++ b/compiler-rt/lib/ubsan/ubsan_flags.cc
@@ -28,7 +28,7 @@ static const char *GetRuntimeFlagsFromCompileDefinition() {
 #endif
 }
 
-void InitializeCommonFlags() {
+static void InitializeCommonFlags() {
   CommonFlags *cf = common_flags();
   SetCommonFlagsDefaults(cf);
   cf->print_summary = false;
@@ -50,6 +50,7 @@ static void ParseFlagsFromString(Flags *f, const char *str) {
 }
 
 void InitializeFlags() {
+  InitializeCommonFlags();
   Flags *f = flags();
   // Default values.
   f->halt_on_error = false;
diff --git a/compiler-rt/lib/ubsan/ubsan_flags.h b/compiler-rt/lib/ubsan/ubsan_flags.h
index 3b1a59e4e19..f41afbd07ac 100644
--- a/compiler-rt/lib/ubsan/ubsan_flags.h
+++ b/compiler-rt/lib/ubsan/ubsan_flags.h
@@ -23,7 +23,6 @@ struct Flags {
 extern Flags ubsan_flags;
 inline Flags *flags() { return &ubsan_flags; }
 
-void InitializeCommonFlags();
 void InitializeFlags();
 
 }  // namespace __ubsan
diff --git a/compiler-rt/lib/ubsan/ubsan_init.cc b/compiler-rt/lib/ubsan/ubsan_init.cc
index 6080e304c12..2649346b1e2 100644
--- a/compiler-rt/lib/ubsan/ubsan_init.cc
+++ b/compiler-rt/lib/ubsan/ubsan_init.cc
@@ -32,15 +32,9 @@ void __ubsan::InitIfNecessary() {
   if (LIKELY(ubsan_inited))
    return;
   if (0 == internal_strcmp(SanitizerToolName, "SanitizerTool")) {
-    // WARNING: If this condition holds, then either UBSan runs in a standalone
-    // mode, or initializer for another sanitizer hasn't run yet. In a latter
-    // case, another sanitizer will overwrite "SanitizerToolName" and reparse
-    // common flags. It means, that we are not allowed to *use* common flags
-    // in this function.
+    // This will be overwritten if another sanitizer will initialize later.
     SanitizerToolName = "UndefinedBehaviorSanitizer";
-    InitializeCommonFlags();
   }
-  // Initialize UBSan-specific flags.
   InitializeFlags();
   SuppressionContext::InitIfNecessary();
   ubsan_inited = true;