Revert "Revert r224736: "[Sanitizer] Make CommonFlags immutable after initialization.""

Fix test failures by introducing CommonFlags::CopyFrom() to make sure
compiler doesn't insert memcpy() calls into runtime code.

Original commit message:
Protect CommonFlags singleton by adding const qualifier to
common_flags() accessor. The only ways to modify the flags are
SetCommonFlagsDefaults(), ParseCommonFlagsFromString() and
OverrideCommonFlags() functions, which are only supposed to be
called during initialization.

llvm-svn: 225088

1 files changed, 13 insertions, 1 deletions

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_flags.h b/compiler-rt/lib/sanitizer_common/sanitizer_flags.h
index f71cf43b278..c39bb781723 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_flags.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_flags.h
@@ -69,11 +69,13 @@ struct CommonFlags {
 
   void SetDefaults();
   void ParseFromString(const char *str);
+
+  void CopyFrom(const CommonFlags &other);
 };
 
 // Functions to get/set global CommonFlags shared by all sanitizer runtimes:
 extern CommonFlags common_flags_dont_use;
-inline CommonFlags *common_flags() {
+inline const CommonFlags *common_flags() {
   return &common_flags_dont_use;
 }
 
@@ -84,6 +86,16 @@ inline void SetCommonFlagsDefaults() {
 inline void ParseCommonFlagsFromString(const char *str) {
   common_flags_dont_use.ParseFromString(str);
 }
+
+// This function can only be used to setup tool-specific overrides for
+// CommonFlags defaults. Generally, it should only be used right after
+// SetCommonFlagsDefaults(), but before ParseCommonFlagsFromString(), and
+// only during the flags initialization (i.e. before they are used for
+// the first time).
+inline void OverrideCommonFlags(const CommonFlags &cf) {
+  common_flags_dont_use.CopyFrom(cf);
+}
+
 void PrintFlagDescriptions();
 
 }  // namespace __sanitizer