On 1/19/21 10:22 AM, Akim Demaille wrote:
Clang 3.3 and 3.4 cannot compile the new scratch-buffer module. On Bison's CI
(Clang 3.4: https://api.travis-ci.org/v3/job/755133481/log.txt), there is:
...
CC lib/lib_libbison_a-canonicalize.o
In file included from ../lib/canonicalize.c:31:
In file included from ../lib/scratch_buffer.h:28:
../lib/malloc/scratch_buffer.h:69:11: error: unknown type name 'max_align_t'
Evidently the stddef module is not arranging for the replacement
stddef.h to define max_align_t properly. Could you investigate why that
might be? What does lib/stddef.h look like? What is the output of 'clang
-E lib/lib_libbison_a-canonicalize.c' (with the proper compile-time
options)?
../lib/canonicalize.c:237:15: warning: declaration does not declare anything
[-Wmissing-declarations]
FALLTHROUGH;
^~~~~~~~~~~
../lib/attribute.h:142:21: note: expanded from macro 'FALLTHROUGH'
#define FALLTHROUGH _GL_ATTRIBUTE_FALLTHROUGH
^~~~~~~~~~~~~~~~~~~~~~~~~
./lib/config.h:2016:36: note: expanded from macro '_GL_ATTRIBUTE_FALLTHROUGH'
# define _GL_ATTRIBUTE_FALLTHROUGH __attribute__ ((__fallthrough__))
My guess is that the preprocessor expands __has_attribute
(__fallthrough__) to 1 but the attribute does not actually work. Is that
the case? Looking at the Clang 3.4 source code, I don't see how that
could be, as clang-3.4/include/clang/Basic/Attr.td lists the
clang::fallthrough attribute for CXX11 but not for C. Possibly I'm
misunderstanding that file, but just to check, does your preprocessor
version match your compiler version? or are you compiling with clang++?
It might not worth worrying about this warning glitch for such an old
compiler, as you can just ignore the bogus warnings.
