[sanitizers] Remove unneeded MaybeCall*DefaultOptions() and nullptr checks

D28596 added SANITIZER_INTERFACE_WEAK_DEF which can guarantee `*_default_options` are always defined.
The weak attributes on the `__{asan,lsan,msan,ubsan}_default_options` declarations can thus be removed.

`MaybeCall*DefaultOptions` no longer need nullptr checks, so their call sites can just be replaced by `__*_default_options`.

Reviewed By: #sanitizers, vitalybuka

Differential Revision: https://reviews.llvm.org/D87175

Author: MaskRay

lib/asan/asan_flags.cpp

@@ -26,10 +26,6 @@ namespace __asan {
 
 Flags asan_flags_dont_use_directly;  // use via flags().
 
-static const char *MaybeCallAsanDefaultOptions() {
-  return (&__asan_default_options) ? __asan_default_options() : "";
-}
-
 static const char *MaybeUseAsanDefaultOptionsCompileDefinition() {
 #ifdef ASAN_DEFAULT_OPTIONS
   return SANITIZER_STRINGIFY(ASAN_DEFAULT_OPTIONS);
@@ -108,14 +104,14 @@ void InitializeFlags() {
   asan_parser.ParseString(asan_compile_def);
 
   // Override from user-specified string.
-  const char *asan_default_options = MaybeCallAsanDefaultOptions();
+  const char *asan_default_options = __asan_default_options();
   asan_parser.ParseString(asan_default_options);
 #if CAN_SANITIZE_UB
-  const char *ubsan_default_options = __ubsan::MaybeCallUbsanDefaultOptions();
+  const char *ubsan_default_options = __ubsan_default_options();
   ubsan_parser.ParseString(ubsan_default_options);
 #endif
 #if CAN_SANITIZE_LEAKS
-  const char *lsan_default_options = __lsan::MaybeCallLsanDefaultOptions();
+  const char *lsan_default_options = __lsan_default_options();
   lsan_parser.ParseString(lsan_default_options);
 #endif
 

lib/asan/asan_interface_internal.h

@@ -174,8 +174,8 @@ extern "C" {
 
   SANITIZER_INTERFACE_ATTRIBUTE void __asan_print_accumulated_stats();
 
-  SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
-  const char* __asan_default_options();
+  SANITIZER_INTERFACE_ATTRIBUTE
+  const char *__asan_default_options();
 
   SANITIZER_INTERFACE_ATTRIBUTE
   extern uptr __asan_shadow_memory_dynamic_address;

lib/cfi/cfi.cpp

@@ -379,7 +379,7 @@ void InitializeFlags() {
   __ubsan::RegisterUbsanFlags(&ubsan_parser, uf);
   RegisterCommonFlags(&ubsan_parser);
 
-  const char *ubsan_default_options = __ubsan::MaybeCallUbsanDefaultOptions();
+  const char *ubsan_default_options = __ubsan_default_options();
   ubsan_parser.ParseString(ubsan_default_options);
   ubsan_parser.ParseStringFromEnv("UBSAN_OPTIONS");
 #endif

lib/hwasan/hwasan.cpp

@@ -112,7 +112,7 @@ static void InitializeFlags() {
   if (__hwasan_default_options)
     parser.ParseString(__hwasan_default_options());
 #if HWASAN_CONTAINS_UBSAN
-  const char *ubsan_default_options = __ubsan::MaybeCallUbsanDefaultOptions();
+  const char *ubsan_default_options = __ubsan_default_options();
   ubsan_parser.ParseString(ubsan_default_options);
 #endif
 

lib/lsan/lsan.cpp

@@ -73,7 +73,7 @@ static void InitializeFlags() {
   RegisterCommonFlags(&parser);
 
   // Override from user-specified string.
-  const char *lsan_default_options = MaybeCallLsanDefaultOptions();
+  const char *lsan_default_options = __lsan_default_options();
   parser.ParseString(lsan_default_options);
   parser.ParseStringFromEnv("LSAN_OPTIONS");
 

lib/lsan/lsan_common.cpp

@@ -110,10 +110,6 @@ void InitializeRootRegions() {
   root_regions = new (placeholder) InternalMmapVector<RootRegion>();
 }
 
-const char *MaybeCallLsanDefaultOptions() {
-  return (&__lsan_default_options) ? __lsan_default_options() : "";
-}
-
 void InitCommonLsan() {
   InitializeRootRegions();
   if (common_flags()->detect_leaks) {
@@ -900,12 +896,11 @@ int __lsan_do_recoverable_leak_check() {
   return 0;
 }
 
-#if !SANITIZER_SUPPORTS_WEAK_HOOKS
-SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
-const char * __lsan_default_options() {
+SANITIZER_INTERFACE_WEAK_DEF(const char *, __lsan_default_options, void) {
   return "";
 }
 
+#if !SANITIZER_SUPPORTS_WEAK_HOOKS
 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 int __lsan_is_turned_off() {
   return 0;

lib/msan/msan.cpp

@@ -172,10 +172,9 @@ static void InitializeFlags() {
 #endif
 
   // Override from user-specified string.
-  if (__msan_default_options)
-    parser.ParseString(__msan_default_options());
+  parser.ParseString(__msan_default_options());
 #if MSAN_CONTAINS_UBSAN
-  const char *ubsan_default_options = __ubsan::MaybeCallUbsanDefaultOptions();
+  const char *ubsan_default_options = __ubsan_default_options();
   ubsan_parser.ParseString(ubsan_default_options);
 #endif
 
@@ -726,12 +725,9 @@ void __msan_finish_switch_fiber(const void **bottom_old, uptr *size_old) {
   }
 }
 
-#if !SANITIZER_SUPPORTS_WEAK_HOOKS
-extern "C" {
-SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
-const char* __msan_default_options() { return ""; }
-}  // extern "C"
-#endif
+SANITIZER_INTERFACE_WEAK_DEF(const char *, __msan_default_options, void) {
+  return "";
+}
 
 extern "C" {
 SANITIZER_INTERFACE_ATTRIBUTE

lib/msan/msan_interface_internal.h

@@ -130,8 +130,8 @@ void __msan_set_keep_going(int keep_going);
 SANITIZER_INTERFACE_ATTRIBUTE
 int __msan_set_poison_in_malloc(int do_poison);
 
-SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
-/* OPTIONAL */ const char* __msan_default_options();
+SANITIZER_INTERFACE_ATTRIBUTE
+const char *__msan_default_options();
 
 // For testing.
 SANITIZER_INTERFACE_ATTRIBUTE

lib/tsan/rtl/tsan_flags.cpp

@@ -87,7 +87,7 @@ void InitializeFlags(Flags *f, const char *env, const char *env_option_name) {
   // Let a frontend override.
   parser.ParseString(__tsan_default_options());
 #if TSAN_CONTAINS_UBSAN
-  const char *ubsan_default_options = __ubsan::MaybeCallUbsanDefaultOptions();
+  const char *ubsan_default_options = __ubsan_default_options();
   ubsan_parser.ParseString(ubsan_default_options);
 #endif
   // Override from command line.

lib/ubsan/ubsan_flags.cpp

@@ -21,10 +21,6 @@
 
 namespace __ubsan {
 
-const char *MaybeCallUbsanDefaultOptions() {
-  return (&__ubsan_default_options) ? __ubsan_default_options() : "";
-}
-
 static const char *GetFlag(const char *flag) {
   // We cannot call getenv() from inside a preinit array initializer
   if (SANITIZER_CAN_USE_PREINIT_ARRAY) {
@@ -66,7 +62,7 @@ void InitializeFlags() {
   RegisterUbsanFlags(&parser, f);
 
   // Override from user-specified string.
-  parser.ParseString(MaybeCallUbsanDefaultOptions());
+  parser.ParseString(__ubsan_default_options());
   // Override from environment variable.
   parser.ParseStringFromEnv("UBSAN_OPTIONS");
   InitializeCommonFlags();

lib/ubsan/ubsan_flags.h

@@ -34,8 +34,6 @@ inline Flags *flags() { return &ubsan_flags; }
 void InitializeFlags();
 void RegisterUbsanFlags(FlagParser *parser, Flags *f);
 
-const char *MaybeCallUbsanDefaultOptions();
-
 }  // namespace __ubsan
 
 extern "C" {