[Bug c/65238] New: [5 Regression] __has_attribute is not handled properly with -traditional-cpp.

iains at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Fri Feb 27 14:20:00 GMT 2015


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65238

            Bug ID: 65238
           Summary: [5 Regression] __has_attribute is not handled properly
                    with -traditional-cpp.
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: iains at gcc dot gnu.org

Created attachment 34890
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34890&action=edit
trivial test-case.

between r218893 and 218951 the handling of __has_attribute has regressed for
-traditional-cpp (-E)

(as an example) gcc.dg/cpp/trad/include.c has started to fail with excess
errors - if run manually:

$ ./gcc/xgcc -Bgcc /GCC/gcc-trunk/gcc/testsuite/gcc.dg/cpp/trad/include.c
-traditional-cpp  -E -m32 -o include.i
In file included from /usr/include/Availability.h:145:0,
                 from /usr/include/stdlib.h:62,
                 from
/GCC/gcc-trunk/gcc/testsuite/gcc.dg/cpp/trad/include.c:13:
/usr/include/AvailabilityInternal.h:1036:0: error: missing '(' after
"__has_attribute"
     #ifdef __has_attribute
 ^
/usr/include/AvailabilityInternal.h:1037:0: error: missing '(' after
"__has_attribute"
         #if __has_attribute(availability)
 ^
=====

The trivial test-case compiles fine with:
$ ./gcc/xgcc -Bgcc has-attr.c -E -o t.i

and with :
$ ./gcc/xgcc -Bgcc has-attr.c -E -traditional-cpp -o t.i
has-attr.c:3:0: error: missing '(' after "__has_attribute"
 # if __has_attribute(__totally_non_existant__)
 ^
cc1(52597) malloc: *** error for object 0x1421194c8: incorrect checksum for
freed object - object was probably modified after being freed.
*** set a breakpoint in malloc_error_break to debug
cc1(52597) malloc: *** error for object 0x142119438: incorrect checksum for
freed object - object was probably modified after being freed.
*** set a breakpoint in malloc_error_break to debug

====

Of course, it seems reasonable to exclude __has_attribute from traditional-cpp
- but, in that case:
(a) the testsuite needs amendment in some places, and
(b) use of the tag should not cause the free error.



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