[Bug c/47816] New: GCC pedwarns about use of static inline functions from system headers in extern inline functions

["lennox at cs dot columbia.edu" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47816

           Summary: GCC pedwarns about use of static inline functions from
                    system headers in extern inline functions
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: lennox@cs.columbia.edu
              Host: x86_64-apple-darwin10.6.0
            Target: x86_64-apple-darwin10.6.0
             Build: x86_64-apple-darwin10.6.0


On Mac OS X 10.6, Apple has modified their system header files to use 'static
inline' functions much more extensively (I believe they're now using fortify by
default?)

However, GCC (since version 4.3) prints an unsuppressible pedwarn about any use
of a static inline function in a non-static inline function.

This essentially means that basic libc functions are unusable from non-static
inline functions.

Thus, on Mac OS X 10.6.6 with a current GCC tree from subversion:

$ cat inline-test.c
#include <string.h>

extern inline __attribute__((__gnu_inline__))
void* memcpy_wrap_1(void* dst, const void* src, size_t n)
{
    return memcpy(dst, src, n);
}

inline
void* memcpy_wrap_2(void* dst, const void* src, size_t n)
{
    return memcpy(dst, src, n);
}


void foo(char *buf1, char *buf2, char *buf3, char *buf4, size_t length)
{
    memcpy_wrap_1(buf1, buf2, length);

    memcpy_wrap_2(buf3, buf4, length);
}


$ ~/GCC/svn/bin/gcc-4.6 -c --std=gnu99
--sysroot=/Developer/SDKs/MacOSX10.6.sdk/ inline-test.c
inline-test.c:12:9: warning: â__inline_memcpy_chkâ is static but used in inline
function âmemcpy_wrap_2â which is not static [enabled by default]
inline-test.c:6:9: warning: â__inline_memcpy_chkâ is static but used in inline
function âmemcpy_wrap_1â which is not static [enabled by default]



Jonathan-Lennoxs-MacBook-Pro:scratch jonathan$ ~/GCC/svn/bin/gcc-4.6 -v -c
--std=gnu99 --sysroot=/Developer/SDKs/MacOSX10.6.sdk/ inline-test.c
Using built-in specs.
COLLECT_GCC=/Users/jonathan/GCC/svn/bin/gcc-4.6
COLLECT_LTO_WRAPPER=/Users/jonathan/GCC/svn/libexec/gcc/x86_64-apple-darwin10.6.0/4.6.0/lto-wrapper
Target: x86_64-apple-darwin10.6.0
Configured with: ../trunk/configure --prefix=/Users/jonathan/GCC/svn
--with-build-config=bootstrap-lto --enable-stage1-languages=c,lto
--enable-languages=c,c++,fortran,lto,objc,obj-c++ --enable-checking=release
--program-suffix=-4.6
Thread model: posix
gcc version 4.6.0 20110218 (experimental) (GCC) 
COLLECT_GCC_OPTIONS='-mmacosx-version-min=10.6.6' '-v' '-c' '-std=gnu99'
'-mtune=core2'
 /Users/jonathan/GCC/svn/libexec/gcc/x86_64-apple-darwin10.6.0/4.6.0/cc1 -quiet
-v -isysroot /Developer/SDKs/MacOSX10.6.sdk/ -D__DYNAMIC__ inline-test.c -fPIC
-quiet -dumpbase inline-test.c -mmacosx-version-min=10.6.6 -mtune=core2
-auxbase inline-test -std=gnu99 -version -o
/var/folders/DK/DKO9pSWtFASzzyjD7MKJl++++TI/-Tmp-//ccg3ldYs.s
GNU C (GCC) version 4.6.0 20110218 (experimental) (x86_64-apple-darwin10.6.0)
    compiled by GNU C version 4.6.0 20110218 (experimental), GMP version 4.3.2,
MPFR version 2.4.2, MPC version 0.8.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory
"/Developer/SDKs/MacOSX10.6.sdk//usr/local/include"
ignoring nonexistent directory
"/Users/jonathan/GCC/svn/lib/gcc/x86_64-apple-darwin10.6.0/4.6.0/../../../../x86_64-apple-darwin10.6.0/include"
#include "..." search starts here:
#include <...> search starts here:
 /Users/jonathan/GCC/svn/lib/gcc/x86_64-apple-darwin10.6.0/4.6.0/include
 /Users/jonathan/GCC/svn/include
 /Users/jonathan/GCC/svn/lib/gcc/x86_64-apple-darwin10.6.0/4.6.0/include-fixed
 /Developer/SDKs/MacOSX10.6.sdk//usr/include
 /Developer/SDKs/MacOSX10.6.sdk//System/Library/Frameworks
 /Developer/SDKs/MacOSX10.6.sdk//Library/Frameworks
End of search list.
GNU C (GCC) version 4.6.0 20110218 (experimental) (x86_64-apple-darwin10.6.0)
    compiled by GNU C version 4.6.0 20110218 (experimental), GMP version 4.3.2,
MPFR version 2.4.2, MPC version 0.8.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 1e40ed1f0984385bdcb3920828281613
inline-test.c:12:9: warning: â__inline_memcpy_chkâ is static but used in inline
function âmemcpy_wrap_2â which is not static [enabled by default]
inline-test.c:6:9: warning: â__inline_memcpy_chkâ is static but used in inline
function âmemcpy_wrap_1â which is not static [enabled by default]
COLLECT_GCC_OPTIONS='-mmacosx-version-min=10.6.6' '-v' '-c' '-std=gnu99'
'-mtune=core2'
 as -arch x86_64 -force_cpusubtype_ALL -o inline-test.o
/var/folders/DK/DKO9pSWtFASzzyjD7MKJl++++TI/-Tmp-//ccg3ldYs.s
COMPILER_PATH=/Users/jonathan/GCC/svn/libexec/gcc/x86_64-apple-darwin10.6.0/4.6.0/:/Users/jonathan/GCC/svn/libexec/gcc/x86_64-apple-darwin10.6.0/4.6.0/:/Users/jonathan/GCC/svn/libexec/gcc/x86_64-apple-darwin10.6.0/:/Users/jonathan/GCC/svn/lib/gcc/x86_64-apple-darwin10.6.0/4.6.0/:/Users/jonathan/GCC/svn/lib/gcc/x86_64-apple-darwin10.6.0/
LIBRARY_PATH=/Users/jonathan/GCC/svn/lib/gcc/x86_64-apple-darwin10.6.0/4.6.0/:/Users/jonathan/GCC/svn/lib/gcc/x86_64-apple-darwin10.6.0/4.6.0/../../../:/Developer/SDKs/MacOSX10.6.sdk//usr/lib/
COLLECT_GCC_OPTIONS='-mmacosx-version-min=10.6.6' '-v' '-c' '-std=gnu99'
'-mtune=core2'


I've reported this in some other contexts in the past: see PR 34000 and PR
42951.


The solutions, as I see it, would either be to fixinclude the Mac OS X header
files (a solution which doesn't work well with the Mac OS X /Developer/SDKs/
pattern of alternate build environments, and which also has problems with
pointers-to-functions), or else (my preference) to suppress this warning if the
static inline function that's being called is defined in a system header file.

(I believe Apple's GCC does the latter.)

This problem did not occur in GCC 4.2, and is thus a regression.