Messages in this thread | | | Date | Tue, 1 Aug 2023 10:51:03 -0700 | Subject | Re: next: arm64: gcc-8-defconfig: ufshcd.c:10629:2: /builds/linux/include/linux/compiler_types.h:397:38: error: call to '__compiletime_assert_553' declared with attribute error: BUILD_BUG_ON failed: | From | Bart Van Assche <> |
| |
On 8/1/23 07:56, Arnd Bergmann wrote: > On Tue, Aug 1, 2023, at 16:23, Naresh Kamboju wrote: >> On Tue, 1 Aug 2023 at 18:53, Bart Van Assche <bvanassche@acm.org> wrote: > >>>> - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20230801/testrun/18754886/suite/build/test/gcc-8-defconfig/log >>>> - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20230801/testrun/18754886/suite/build/test/gcc-8-defconfig/details/ >>>> - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20230801/testrun/18754886/suite/build/test/gcc-8-defconfig/history/ >>> >>> I can't reproduce this build error with a gcc-12 arm64 cross-compiler. How >>> important is gcc-8 for the ARM community? >> >> You are right, >> gcc-12 build pass. >> gcc-8 build failed. > > I can also reproduce this with gcc-9.5.0 from > https://mirrors.edge.kernel.org/pub/tools/crosstool/ but > not with 10.5.0 or clang. > > I get the same results for x86 with gcc-9.5.0. > > See https://godbolt.org/z/GjGrW9znc for a partially reduced testcase. Thanks Arnd, this is very helpful. The first error message reported for that test case is as follows:
<source>:34:286: error: call to '__compiletime_assert_655' declared with attribute error: BUILD_BUG_ON failed: ((u8 *)&(struct request_desc_header){ .enable_crypto = 1})[2] != 0x80 34 | do { __attribute__((__noreturn__)) extern void __compiletime_assert_655(void) __attribute__((__error__("BUILD_BUG_ON failed: " "((u8 *)&(struct request_desc_header){ .enable_crypto = 1})[2] != 0x80"))); if (!(!(((u8 *)&(struct request_desc_header){ .enable_crypto = 1})[2] != 0x80))) __compiletime_assert_655(); } while (0); |
If I change the return type of ufshcd_check_header_layout() from void into unsigned int and insert the following at the start of that function:
return ((u8 *)&(struct request_desc_header){ .enable_crypto = 1})[2] != 0x80;
then the compiler shows the following in the output window:
xorl %eax, %eax
In other words, the expression next to the return statement evaluates to zero but the same expression does not evaluate to zero in the BUILD_BUG_ON() statement. Does this perhaps indicate a compiler bug? And if so, what is the appropriate way to fix the build error? Insert an #ifdef/#endif pair inside ufshcd_check_header_layout() such that the compile-time checks do not happen for gcc version 9 or older?
Thanks,
Bart.
| |