[Bug driver/115368] New: Wrong order of gcc include paths on musl systems

[Bug driver/115368] New: Wrong order of gcc include paths on musl systems

[raj.khem at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115368

            Bug ID: 115368
           Summary: Wrong order of gcc include paths on musl systems
           Product: gcc
           Version: 14.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: driver
          Assignee: unassigned at gcc dot gnu.org
          Reporter: raj.khem at gmail dot com
  Target Milestone: ---

When doing cross-builds targeting musl based systems, gcc driver adds -iprefix
to cc1/cc1plus call, the path is based on gcc cross compiler installation
location, and points to GCC private headers which override some of system
headers e.g. stddef.h stdint.h, stdarg.h to name a few. This works ok with
glibc based systems but musl does not depend/use gcc's private headers [1] and
-iprefix prepends to search path which means the headers from gcc installation
will be picked up first. This causes problems e.g. when configuring python
build, it tries to detect platform and logic to detect musl system is based on
musl specific define coming from stdarg.h, however musl cross gcc feeds the
gcc's own stdarg.h header and the test fails. 

[1] https://gitlab.alpinelinux.org/alpine/aports/-/issues/12477#note_145159

[Bug driver/115368] Wrong order of gcc include paths on musl systems

[raj.khem at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115368

--- Comment #1 from Khem Raj <raj.khem at gmail dot com> ---
Created attachment 58366
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58366&action=edit
potential fix

This patch uses -idirafter instead of -iprefix when building for musl. This
fixes the issue as the search paths get adjusted and sysroot is searched before
gcc headers dir.

[Bug driver/115368] Wrong order of gcc include paths on musl systems

[raj.khem at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115368

Khem Raj <raj.khem at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #58366|0                           |1
        is obsolete|                            |

--- Comment #2 from Khem Raj <raj.khem at gmail dot com> ---
Created attachment 58370
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58370&action=edit
potential fix v2

[Bug driver/115368] Wrong order of gcc include paths on musl systems

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115368

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Please send patch to the gcc-patches mailing list rather than attaching them
here.

https://gcc.gnu.org/contribute.html#patches

[Bug driver/115368] Wrong order of gcc include paths on musl systems

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115368

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note this patch does not work as OPTION_MUSL is not defined for all targets.
e.g. *-*-darwin and *-*-elf* targets do not define it.

[Bug driver/115368] Wrong order of gcc include paths on musl systems

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115368

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2024-06-06
     Ever confirmed|0                           |1

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Also how come glibc targets get it correct:
[apinski@xeond2 gcc]$ ~/upstream-gcc-match/bin/gcc -E -Wp,-v -
ignoring nonexistent directory
"/home/apinski/upstream-gcc-match/lib/gcc/x86_64-pc-linux-gnu/15.0.0/../../../../x86_64-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /home/apinski/upstream-gcc-match/lib/gcc/x86_64-pc-linux-gnu/15.0.0/include
 /usr/local/include
 /home/apinski/upstream-gcc-match/include

/home/apinski/upstream-gcc-match/lib/gcc/x86_64-pc-linux-gnu/15.0.0/include-fixed
 /usr/include

[Bug driver/115368] Wrong order of gcc include paths on musl systems

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115368

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
> musl does not depend/use gcc's private headers

Which is wrong and broken.