[PATCH] D150966: [clang] Don't define predefined macros multiple times

[John Brawn via Phabricator via cfe-commits]

john.brawn marked an inline comment as done.
john.brawn added inline comments.


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Comment at: clang/lib/Basic/Targets/AArch64.cpp:241-242
   Builder.defineMacro("__ARM_FEATURE_QRDMX", "1");
-  Builder.defineMacro("__ARM_FEATURE_ATOMICS", "1");
-  Builder.defineMacro("__ARM_FEATURE_CRC32", "1");
 }
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aaron.ballman wrote:
> john.brawn wrote:
> > aaron.ballman wrote:
> > > Hmm, is this correct?
> > > 
> > > `__ARM_FEATURE_ATOMICS` is defined in one other place, but it's conditionally defined: https://github.com/llvm/llvm-project/blob/11926e6149d2a68ecb0652b248efe6890c163846/clang/lib/Basic/Targets/AArch64.cpp#L475
> > > 
> > > and `__ARM_FEATURE_CRC32` is defined in two places, both conditional: https://github.com/llvm/llvm-project/blob/11926e6149d2a68ecb0652b248efe6890c163846/clang/lib/Basic/Targets/AArch64.cpp#L422 and https://github.com/llvm/llvm-project/blob/11926e6149d2a68ecb0652b248efe6890c163846/clang/lib/Basic/Targets/ARM.cpp#L747
> > > 
> > > 
> > AArch64TargetInfo::setArchFeatures sets HasCRC and HasLSE to true for >= 8.1. This does mean that if you do `-march=armv8.1-a+nocrc` then the current behaviour is that __ARM_FEATURE_CRC32 is defined but the behaviour with this patch is that it's not defined, but the new behaviour is correct as we shouldn't be defining it in that case.
> Ah, okay! I think it's worth adding a test case for that scenario to show we've made a bugfix here, not just an NFC change.
Actually I went and double-checked and I'm wrong, `-march=armv8.N+nowhatever` doesn't cause __ARM_FEATURE_WHATEVER to be undefined. Which seems wrong, but it's beyond the scope of this patch.


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Comment at: clang/lib/Basic/Targets/VE.cpp:30-32
-  Builder.defineMacro("unix", "1");
-  Builder.defineMacro("__unix__", "1");
-  Builder.defineMacro("__linux__", "1");
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aaron.ballman wrote:
> john.brawn wrote:
> > aaron.ballman wrote:
> > > Shouldn't this be calling `DefineStd(Builder, "unix", Opts);` like all the others?
> > Only the OS target should be defining OS-related macros, and in AllocateTarget in Targets.cpp VETargetInfo is hardcoded to always use LinuxTargetInfo, which calls `DefineStd(Builder, "unix", Opts);`.
> Hmmm, we still have calls to this outside of `getOSDefines()` though?
> 
> https://github.com/llvm/llvm-project/blob/main/clang/lib/Basic/Targets/ARM.cpp#L1400
> https://github.com/llvm/llvm-project/blob/main/clang/lib/Basic/Targets/Le64.cpp#L28
> https://github.com/llvm/llvm-project/blob/main/clang/lib/Basic/Targets/X86.h#L634
> https://github.com/llvm/llvm-project/blob/main/clang/lib/Basic/Targets/X86.h#L907
> 
> should those also be changing (perhaps in a follow-up)?
Most of these are TargetInfos that combine OS plus target, e.g. CygwinARMTargetInfo is both Cygwin OS and ARM Target. The only exception is Le64, and I have no idea if it's correct or not for it to be doing that.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D150966/new/

https://reviews.llvm.org/D150966