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| author |   Miguel Ojeda <ojeda@kernel.org> | 2021-10-14 15:23:31 +0200 |
|---|---|---|
| committer | Miguel Ojeda <ojeda@kernel.org> | 2021-10-22 01:16:58 +0200 |
| commit | 7c00621dcaeea206d7489b3e8b50b1864841ae69 (patch) | |
| tree | 2f3b4b8cc9390b74f0130fee1366bdf4a0211147 /include/linux/compiler_types.h | |
| parent | Compiler Attributes: remove GCC 5.1 mention (diff) | |
| download | wireguard-linux-7c00621dcaeea206d7489b3e8b50b1864841ae69.tar.xz wireguard-linux-7c00621dcaeea206d7489b3e8b50b1864841ae69.zip | |
compiler_types: mark __compiletime_assert failure as __noreturn
`__compiletime_assert` declares a fake `extern` function
which appears (to the compiler) to be called when the test fails.
Therefore, compilers may emit possibly-uninitialized warnings
in some cases, even if it will be an error anyway (for compilers
supporting the `error` attribute, e.g. GCC and Clang >= 14)
or a link failure (for those that do not, e.g. Clang < 14).
Annotating the fake function as `__noreturn` gives them
the information they need to avoid the warning,
e.g. see https://godbolt.org/z/x1v69jjYY.
Link: https://lore.kernel.org/llvm/202110100514.3h9CI4s0-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'include/linux/compiler_types.h')
| -rw-r--r-- | include/linux/compiler_types.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index b6ff83a714ca..ca1a66b8cd2f 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -298,7 +298,13 @@ struct ftrace_likely_data { #ifdef __OPTIMIZE__ # define __compiletime_assert(condition, msg, prefix, suffix) \ do { \ - extern void prefix ## suffix(void) __compiletime_error(msg); \ + /* \ + * __noreturn is needed to give the compiler enough \ + * information to avoid certain possibly-uninitialized \ + * warnings (regardless of the build failing). \ + */ \ + __noreturn extern void prefix ## suffix(void) \ + __compiletime_error(msg); \ if (!(condition)) \ prefix ## suffix(); \ } while (0) |