[PATCH] D122271: [Clang] -Wunused-but-set-variable warning - handle also pre/post unary operators

Mon Mar 28 22:51:56 PDT 2022

xbolva00 added a comment.

In D122271#3413193 <https://reviews.llvm.org/D122271#3413193>, @uabelho wrote:

> Hi,
>
> I noticed these to warning when compiling libunwind/src/UnwindLevel1.c with this patch:
>
>   00:22:48 /repo/bbiswjenk/fem2s10-eiffel176/workspace/llvm/sdk_1_20_ki_dev_test/libunwind/src/UnwindLevel1.c:175:12: warning: variable 'framesWalked' set but not used [-Wunused-but-set-variable]
>   00:22:48   unsigned framesWalked = 1;
>   00:22:48            ^
>   00:22:48 /repo/bbiswjenk/fem2s10-eiffel176/workspace/llvm/sdk_1_20_ki_dev_test/libunwind/src/UnwindLevel1.c:293:12: warning: variable 'framesWalked' set but not used [-Wunused-but-set-variable]
>   00:22:48   unsigned framesWalked = 1;
>   00:22:48            ^
>   00:22:48 2 warnings generated.

In D122271#3413193 <https://reviews.llvm.org/D122271#3413193>, @uabelho wrote:

> Hi,
>
> I noticed these to warning when compiling libunwind/src/UnwindLevel1.c with this patch:
>
>   00:22:48 /repo/bbiswjenk/fem2s10-eiffel176/workspace/llvm/sdk_1_20_ki_dev_test/libunwind/src/UnwindLevel1.c:175:12: warning: variable 'framesWalked' set but not used [-Wunused-but-set-variable]
>   00:22:48   unsigned framesWalked = 1;
>   00:22:48            ^
>   00:22:48 /repo/bbiswjenk/fem2s10-eiffel176/workspace/llvm/sdk_1_20_ki_dev_test/libunwind/src/UnwindLevel1.c:293:12: warning: variable 'framesWalked' set but not used [-Wunused-but-set-variable]
>   00:22:48   unsigned framesWalked = 1;
>   00:22:48            ^
>   00:22:48 2 warnings generated.

A warning was improved so fires more often.

Clearly, sometimes in __unw_phase2_resume, “fn” is ignored (so passed framesWalked is throw away as well). I see nothing wrong to warn here.

(void)framesWalked; will silence it.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D122271/new/

https://reviews.llvm.org/D122271