[Bug lto/95194] New: bootstrap-lto fails on musl (bundled libintl uses asm aliases)

[Bug lto/95194] New: bootstrap-lto fails on musl (bundled libintl uses asm aliases)

[slyfox at inbox dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95194

            Bug ID: 95194
           Summary: bootstrap-lto fails on musl (bundled libintl uses asm
                    aliases)
           Product: gcc
           Version: 10.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: slyfox at inbox dot ru
                CC: hubicka at gcc dot gnu.org, marxin at gcc dot gnu.org
  Target Milestone: ---

The bug is originally reported by Andrew Savchenko as
https://bugs.gentoo.org/723370. There gcc's bootstrap-lto fails on musl libc.
It's slightly different from glibc as libintl relies on glibc-specific gettext
symbols like '_nl_msg_cat_cntr'.

The bug:

$ /var/tmp/portage/sys-devel/gcc-10.1.0/work/gcc-10.1.0/configure
--host=x86_64-gentoo-linux-musl --build=x86_64-gentoo-linux-musl --prefix=/usr
--bindir=/usr/x86_64-gentoo-linux-musl/gcc-bin/10.1.0
--includedir=/usr/lib/gcc/x86_64-gentoo-linux-musl/10.1.0/include
--datadir=/usr/share/gcc-data/x86_64-gentoo-linux-musl/10.1.0
--mandir=/usr/share/gcc-data/x86_64-gentoo-linux-musl/10.1.0/man
--infodir=/usr/share/gcc-data/x86_64-gentoo-linux-musl/10.1.0/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-gentoo-linux-musl/10.1.0/include/g++-v10
--with-python-dir=/share/gcc-data/x86_64-gentoo-linux-musl/10.1.0/python
--enable-languages=c,c++ --enable-obsolete --enable-secureplt --disable-werror
--with-system-zlib --enable-nls --without-included-gettext
--enable-checking=release --with-bugurl=https://bugs.gentoo.org/
--with-pkgversion=Gentoo Hardened 10.1.0 p1 --enable-esp
--enable-libstdcxx-time --with-build-config=bootstrap-lto
--disable-libstdcxx-pch --enable-shared --enable-threads=posix
--enable-__cxa_atexit --disable-multilib --with-multilib-list=m64
--disable-altivec --disable-fixed-point --enable-targets=all --enable-libgomp
--disable-libmudflap --disable-libssp --disable-libada --disable-systemtap
--disable-vtable-verify --disable-libvtv --without-zstd --disable-libquadmath
--enable-lto --without-isl --disable-libsanitizer --enable-default-pie
--enable-default-ssp

$ make -j8 -l10 'LDFLAGS=-march=native -pipe
-Wl,-O1,--as-needed,--sort-common,-z,combreloc,-z,relro,-z,now,--relax,--hash-style=gnu'
STAGE1_CFLAGS= LIBPATH=/usr/lib/gcc/x86_64-gentoo-linux-musl/10.1.0
'BOOT_CFLAGS=-m64 -march=native -pipe -O2' bootstrap-lean

/var/tmp/portage/sys-devel/gcc-10.1.0/work/build/./prev-gcc/xg++
-B/var/tmp/portage/sys-devel/gcc-10.1.0/work/build/./prev-gcc/
-B/usr/x86_64-gentoo-linux-musl/bin/ -nostdinc++
-B/var/tmp/portage/sys-devel/gcc-10.1.0/work/build/prev-x86_64-gentoo-linux-musl/libstdc++-v3/src/.libs
-B/var/tmp/portage/sys-devel/gcc-10.1.0/work/build/prev-x86_64-gentoo-linux-musl/libstdc++-v3/libsupc++/.libs
 -isystem
/var/tmp/portage/sys-devel/gcc-10.1.0/work/build/prev-x86_64-gentoo-linux-musl/libstdc++-v3/include/x86_64-gentoo-linux-musl
 -isystem
/var/tmp/portage/sys-devel/gcc-10.1.0/work/build/prev-x86_64-gentoo-linux-musl/libstdc++-v3/include
 -isystem
/var/tmp/portage/sys-devel/gcc-10.1.0/work/gcc-10.1.0/libstdc++-v3/libsupc++
-L/var/tmp/portage/sys-devel/gcc-10.1.0/work/build/prev-x86_64-gentoo-linux-musl/libstdc++-v3/src/.libs
-L/var/tmp/portage/sys-devel/gcc-10.1.0/work/build/prev-x86_64-gentoo-linux-musl/libstdc++-v3/libsupc++/.libs
-DEXTRA_OPTIONS     -m64 -march=native -pipe -O2 -fno-checking -flto=jobserver
-frandom-seed=1 -DIN_GCC     -fno-exceptions -fno-rtti
-fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings
-Wcast-qual -Wno-error=format-diag -Wmissing-format-attribute
-Woverloaded-virtual -pedantic -Wno-long-long -Wno-variadic-macros
-Wno-overlength-strings   -DHAVE_CONFIG_H  -DGENERATOR_FILE -fno-PIE
-static-libstdc++ -static-libgcc  -no-pie -o build/genmatch \
    build/genmatch.o ../libcpp/libcpp.a ../libiberty/libiberty.a build/errors.o
build/vec.o build/hash-table.o build/sort.o .././libiberty/libiberty.a
./../intl/libintl.a
...
/usr/x86_64-gentoo-linux-musl/bin/ld:
/var/tmp/portage/sys-devel/gcc-10.1.0/temp/genmatch.NlicMk.ltrans2.ltrans.o: in
function `main':
<artificial>:(.text.startup+0x94ba): undefined reference to `libintl_dgettext'
/usr/x86_64-gentoo-linux-musl/bin/ld:
/var/tmp/portage/sys-devel/gcc-10.1.0/temp/genmatch.NlicMk.ltrans3.ltrans.o: in
function `cpp_diagnostic(cpp_reader*, cpp_diagnostic_level, cpp_warning_reason,
char const*, __va_list_tag (*) [1])':
<artificial>:(.text+0x2732): undefined reference to `libintl_dgettext'
...

Mechanically it fails because 'libintl_dgettext' is decclared as an asm alias:

"""
extern char *dgettext (const char *__domainname, const char *__msgid)
       __asm__ ("" "libintl_dgettext")
       __attribute__ ((__format_arg__ (2)));

$ ../prev-gcc/lto-dump -list errors.o | fgrep dgettext
function  default     0  *libintl_dgettext
$ ../prev-gcc/lto-dump -demangle -list errors.o | fgrep dgettext
function  default     0  dgettext
"""

I'm not sure if gcc should be able to link such a use case for partition=1.
Maybe?

Otherwise maybe gcc should default to more portable macro/inline definition of
gettext wrappers.

The following workaround helps musl target:

--- a/intl/libgnuintl.h
+++ b/intl/libgnuintl.h
@@ -84,25 +84,25 @@ extern "C" {
    Since Solaris gettext() behaves differently than GNU gettext(), this
    would be unacceptable.

    The redirection happens by default through macros in C, so that &gettext
    is independent of the compilation unit, but through inline functions in
    C++, in order not to interfere with the name mangling of class fields or
    class methods called 'gettext'.  */

 /* The user can define _INTL_REDIRECT_INLINE or _INTL_REDIRECT_MACROS.
    If he doesn't, we choose the method.  A third possible method is
    _INTL_REDIRECT_ASM, supported only by GCC.  */
 #if !(defined _INTL_REDIRECT_INLINE || defined _INTL_REDIRECT_MACROS)
-# if __GNUC__ >= 2 && !defined __APPLE_CC__ && (defined __STDC__ || defined
__cplusplus)
+# if __GNUC__ >= 2 && !defined __APPLE_CC__ && (defined __STDC__ || defined
__cplusplus) && USE_ASM_ALIASES_THAT_BREAK_LTO
 #  define _INTL_REDIRECT_ASM
 # else
 #  ifdef __cplusplus
 #   define _INTL_REDIRECT_INLINE
 #  else
 #   define _INTL_REDIRECT_MACROS
 #  endif
 # endif
 #endif
 /* Auxiliary macros.  */
 #ifdef _INTL_REDIRECT_ASM
 # define _INTL_ASM(cname) __asm__ (_INTL_ASMNAME (__USER_LABEL_PREFIX__,
#cname))

[Bug lto/95194] bootstrap-lto fails on musl (bundled libintl uses asm aliases)

[slyfox at inbox dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95194

--- Comment #1 from Sergei Trofimovich <slyfox at inbox dot ru> ---
https://gcc.gnu.org/PR48200 touches on why asm aliases are problematic.

[Bug lto/95194] bootstrap-lto fails on musl (bundled libintl uses asm aliases)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95194

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2020-05-19
             Status|UNCONFIRMED                 |NEW

[Bug lto/95194] bootstrap-lto fails on musl (bundled libintl uses asm aliases)

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95194

Sam James <sjames at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |arsen at gcc dot gnu.org

--- Comment #2 from Sam James <sjames at gcc dot gnu.org> ---
I think this is fixed for 14 (although not tried a musl build) as the bundled
old intl/ is now gone as of r14-5423-gfbe4e64365ec7f.

[Bug lto/95194] bootstrap-lto fails on musl (bundled libintl uses asm aliases)

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95194

Sergei Trofimovich <slyfox at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |slyfox at gcc dot gnu.org
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #3 from Sergei Trofimovich <slyfox at gcc dot gnu.org> ---
Sounds good. Let's declared it FIXED for 14.0.