[PATCH] D66609: Allow Compiler.h to be included in C files and fix fallthrough warnings

[Aaron Ballman via Phabricator via llvm-commits]

aaron.ballman added a reviewer: rsmith.
aaron.ballman added a subscriber: rsmith.
aaron.ballman added a comment.

Adding @rsmith as a reviewer just to be sure we are not missing something.



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Comment at: llvm/include/llvm/Support/Compiler.h:40-42
 #ifndef __has_cpp_attribute
 # define __has_cpp_attribute(x) 0
 #endif
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I think that we want people to use `LLVM_HAS_CPP_ATTRIBUTE` instead of `__has_cpp_attribute` directly, so I think that this block should be removed.


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Comment at: llvm/include/llvm/Support/Compiler.h:48
 
+#ifndef LLVM_HAS_CPP_ATTRIBUTE
+#ifdef __cplusplus
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I would appreciate some comments explaining why this is needed so that someone doesn't come in and "fix" the code by removing the macro later without understanding why it's there.


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Comment at: llvm/include/llvm/Support/Compiler.h:49
+#ifndef LLVM_HAS_CPP_ATTRIBUTE
+#ifdef __cplusplus
+# define LLVM_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
----------------
Then this can also check for `defined(__has_cpp_attribute)`


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D66609/new/

https://reviews.llvm.org/D66609