From: Zenghui Yu <yuzeng...@huawei.com> Our robot reported the following compile-time warning while compiling Qemu with -fno-inline cflags:
In function 'load_memop', inlined from 'load_helper' at /qemu/accel/tcg/cputlb.c:1578:20, inlined from 'full_ldub_mmu' at /qemu/accel/tcg/cputlb.c:1624:12: /qemu/accel/tcg/cputlb.c:1502:9: error: call to 'qemu_build_not_reached' declared with attribute error: code path is reachable qemu_build_not_reached(); ^~~~~~~~~~~~~~~~~~~~~~~~ [...] It looks like a false-positive because only (MO_UB ^ MO_BSWAP) will hit the default case in load_memop() while need_swap (size > 1) has already ensured that MO_UB is not involved. So the thing is that compilers get confused by the -fno-inline and just can't accurately evaluate memop_size(op) at compile time, and then the qemu_build_not_reached() is wrongly triggered by (MO_UB ^ MO_BSWAP). Let's carefully don't use the compile-time assert when no functions will be inlined into their callers. Reported-by: Euler Robot <euler.ro...@huawei.com> Suggested-by: Richard Henderson <richard.hender...@linaro.org> Signed-off-by: Zenghui Yu <yuzeng...@huawei.com> Message-Id: <20200205141545.180-1-yuzeng...@huawei.com> Signed-off-by: Richard Henderson <richard.hender...@linaro.org> --- include/qemu/compiler.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index 85c02c16d3..c76281f354 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -236,7 +236,7 @@ * supports QEMU_ERROR, this will be reported at compile time; otherwise * this will be reported at link time due to the missing symbol. */ -#ifdef __OPTIMIZE__ +#if defined(__OPTIMIZE__) && !defined(__NO_INLINE__) extern void QEMU_NORETURN QEMU_ERROR("code path is reachable") qemu_build_not_reached(void); #else -- 2.20.1