Merge pull request 'Replace MOZ_FALLTHROUGH with [[fallthrough]]' (#2379) from 2343-fallthrough-work into master

Reviewed-on: https://repo.palemoon.org/MoonchildProductions/UXP/pulls/2379

2 files changed, 2 insertions, 46 deletions

diff --git a/mfbt/Assertions.h b/mfbt/Assertions.h
index 09a1b8eaa6..a965ae6f1d 100644
--- a/mfbt/Assertions.h
+++ b/mfbt/Assertions.h
@@ -554,7 +554,7 @@ struct AssertionConditionType
  *   default:
  *     // This case wants to assert in debug builds, fall through in release.
  *     MOZ_ASSERT(false); // -Wimplicit-fallthrough warning in release builds!
- *     MOZ_FALLTHROUGH;   // but -Wunreachable-code warning in debug builds!
+ *     [[fallthrough]];   // but -Wunreachable-code warning in debug builds!
  *   case 5:
  *     return 5;
  * }
@@ -571,7 +571,7 @@ struct AssertionConditionType
 #ifdef DEBUG
 #  define MOZ_FALLTHROUGH_ASSERT(reason) MOZ_CRASH("MOZ_FALLTHROUGH_ASSERT: " reason)
 #else
-#  define MOZ_FALLTHROUGH_ASSERT(...) MOZ_FALLTHROUGH
+#  define MOZ_FALLTHROUGH_ASSERT(...) [[fallthrough]]
 #endif
 
 /*
diff --git a/mfbt/Attributes.h b/mfbt/Attributes.h
index fdd253d357..5da4ffe948 100644
--- a/mfbt/Attributes.h
+++ b/mfbt/Attributes.h
@@ -238,50 +238,6 @@
 
 #ifdef __cplusplus
 
-/**
- * MOZ_FALLTHROUGH is an annotation to suppress compiler warnings about switch
- * cases that fall through without a break or return statement. MOZ_FALLTHROUGH
- * is only needed on cases that have code.
- *
- * MOZ_FALLTHROUGH_ASSERT is an annotation to suppress compiler warnings about
- * switch cases that MOZ_ASSERT(false) (or its alias MOZ_ASSERT_UNREACHABLE) in
- * debug builds, but intentionally fall through in release builds. See comment
- * in Assertions.h for more details.
- *
- * switch (foo) {
- *   case 1: // These cases have no code. No fallthrough annotations are needed.
- *   case 2:
- *   case 3: // This case has code, so a fallthrough annotation is needed!
- *     foo++;
- *     MOZ_FALLTHROUGH;
- *   case 4:
- *     return foo;
- *
- *   default:
- *     // This case asserts in debug builds, falls through in release.
- *     MOZ_FALLTHROUGH_ASSERT("Unexpected foo value?!");
- *   case 5:
- *     return 5;
- * }
- */
-#ifndef __has_cpp_attribute
-#  define __has_cpp_attribute(x) 0
-#endif
-
-#if __has_cpp_attribute(clang::fallthrough)
-#  define MOZ_FALLTHROUGH [[clang::fallthrough]]
-#elif __has_cpp_attribute(gnu::fallthrough)
-#  define MOZ_FALLTHROUGH [[gnu::fallthrough]]
-#elif defined(_MSC_VER)
-   /*
-    * MSVC's __fallthrough annotations are checked by /analyze (Code Analysis):
-    * https://msdn.microsoft.com/en-us/library/ms235402%28VS.80%29.aspx
-    */
-#  include <sal.h>
-#  define MOZ_FALLTHROUGH __fallthrough
-#else
-#  define MOZ_FALLTHROUGH /* FALLTHROUGH */
-#endif
 /*
  * MOZ_ASAN_BLACKLIST is a macro to tell AddressSanitizer (a compile-time
  * instrumentation shipped with Clang and GCC) to not instrument the annotated