| Message ID | 20181022181623.8810-1-richard.henderson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [build,fix] osdep: Work around MinGW assert | expand |
On 10/22/18 7:16 PM, Richard Henderson wrote:
> + * not marked a noreturn, so the compiler cannot delete code following an
Bah. Peter, if you apply this directly, can you please fix the grammar around
"marked a return" (either s/a/as/ or s/a// sound equally plausible for me).
r~
On 22/10/18 20:16, Richard Henderson wrote: > In several places we use assert(FEATURE), and assume that if FEATURE > is disabled, all following code is removed as unreachable. Which allows > us to compile-out functions that are only present with FEATURE, and > have a link-time failure if the functions remain used. > > MinGW does not mark its internal function _assert() as noreturn, so the > compiler cannot see when code is unreachable, which leads to link errors > for this host that are not present elsewhere. > > The current build-time failure concerns 62823083b8a2, but I remember > having seen this same error before. Fix it once and for all for MinGW. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > --- > include/qemu/osdep.h | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h > index 4f8559e550..0c1e335a43 100644 > --- a/include/qemu/osdep.h > +++ b/include/qemu/osdep.h > @@ -122,6 +122,18 @@ extern int daemon(int, int); > #include "glib-compat.h" > #include "qemu/typedefs.h" > > +/* > + * For mingw, as of v6.0.0, the function implementing the assert macro is > + * not marked a noreturn, so the compiler cannot delete code following an > + * assert(false) as unused. We rely on this within the code base to delete > + * code that is unreachable when features are disabled. > + * All supported versions of Glib's g_assert() satisfy this requirement. > + */ > +#ifdef __MINGW32__ > +#undef assert > +#define assert(x) g_assert(x) > +#endif > + > /* > * According to waitpid man page: > * WCOREDUMP >
On 22 October 2018 at 19:16, Richard Henderson <richard.henderson@linaro.org> wrote: > In several places we use assert(FEATURE), and assume that if FEATURE > is disabled, all following code is removed as unreachable. Which allows > us to compile-out functions that are only present with FEATURE, and > have a link-time failure if the functions remain used. > > MinGW does not mark its internal function _assert() as noreturn, so the > compiler cannot see when code is unreachable, which leads to link errors > for this host that are not present elsewhere. > > The current build-time failure concerns 62823083b8a2, but I remember > having seen this same error before. Fix it once and for all for MinGW. > Applied to master (with the typo fixed), thanks. -- PMM
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 4f8559e550..0c1e335a43 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -122,6 +122,18 @@ extern int daemon(int, int); #include "glib-compat.h" #include "qemu/typedefs.h" +/* + * For mingw, as of v6.0.0, the function implementing the assert macro is + * not marked a noreturn, so the compiler cannot delete code following an + * assert(false) as unused. We rely on this within the code base to delete + * code that is unreachable when features are disabled. + * All supported versions of Glib's g_assert() satisfy this requirement. + */ +#ifdef __MINGW32__ +#undef assert +#define assert(x) g_assert(x) +#endif + /* * According to waitpid man page: * WCOREDUMP
In several places we use assert(FEATURE), and assume that if FEATURE is disabled, all following code is removed as unreachable. Which allows us to compile-out functions that are only present with FEATURE, and have a link-time failure if the functions remain used. MinGW does not mark its internal function _assert() as noreturn, so the compiler cannot see when code is unreachable, which leads to link errors for this host that are not present elsewhere. The current build-time failure concerns 62823083b8a2, but I remember having seen this same error before. Fix it once and for all for MinGW. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- include/qemu/osdep.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) -- 2.17.2