[MacPorts] #27237: gcc46: checking for -exported_symbols_list linker flag... configure: error: Link tests are not allowed after GCC_NO_EXECUTABLES.

[MacPorts]

#27237: gcc46: checking for -exported_symbols_list linker flag... configure: error:
Link tests are not allowed after GCC_NO_EXECUTABLES.
-------------------------------------+--------------------------------------
 Reporter:  ryandesign@…             |       Owner:  mww@…           
     Type:  defect                   |      Status:  new             
 Priority:  Normal                   |   Milestone:                  
Component:  ports                    |     Version:  1.9.2           
 Keywords:                           |        Port:  gcc46           
-------------------------------------+--------------------------------------

Comment(by ionic@…):

 Nope, won't work, as _GLIBCXX_FULLY_DYNAMIC_STRING is set by --enable-
 fully-dynamic-string already.

 Ok, some more information here.

 For once, I found out through debugging that !__p is null/0x0, although
 this shouldn't ever happen (at least the code says so in
 new_allocator.h:98:

 {{{
       // __p is not permitted to be a null pointer.
       void
       deallocate(pointer __p, size_type)
       { ::operator delete(__p); }
 }}}

 Then, I tried to manually reproduce the problem with conftest3.c:

 {{{
 int foo(void){return 1;}
 }}}

 and this command line:

 {{{
 /opt/local/var/macports/build/_opt_local_var_macports_sources_macports.rsync.ionic.de_release_ports_lang_gcc46/gcc46/work/build/./gcc/xgcc
 -B/opt/local/var/macports/build/_opt_local_var_macports_sources_macports.rsync.ionic.de_release_ports_lang_gcc46/gcc46/work/build/./gcc/
 -B/opt/local/x86_64-apple-darwin10/bin/ -B/opt/local/x86_64-apple-
 darwin10/lib/ -isystem /opt/local/x86_64-apple-darwin10/include -isystem
 /opt/local/x86_64-apple-darwin10/sys-include    -g -pipe -O2  -o
 libconftest.dylib -dynamiclib -Wl,-single_module conftest3.c
 }}}

 This, however, worked fine and didn't crash. Having a look at otool -L
 /usr/bin/ld (which is crashing...) shows that...

 {{{
 /usr/bin/ld.orig:
         /usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current
 version 7.9.0)
         /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current
 version 125.2.0)
         @executable_path/../lib/libLTO.dylib (compatibility version 1.0.0,
 current version 3135.0.0)
 }}}

 The ld binary actually dynamically links to the libstdc++. Now, as we
 build GCC 4.6 and for that matter also a newer libstdc++, the build system
 probably tried to use that new lib instead of the system library. We can
 "emulate" this by using the following command line (when PWD ==
 /opt/local/var/macports/build/_opt_local_var_macports_sources_macports.rsync.ionic.de_release_ports_lang_gcc46/gcc46/work/build/x86_64
 -apple-darwin10/libssp):

 {{{
 DYLD_LIBRARY_PATH="../libstdc++-v3/src/.libs/"
 /opt/local/var/macports/build/_opt_local_var_macports_sources_macports.rsync.ionic.de_release_ports_lang_gcc46/gcc46/work/build/./gcc/xgcc
 -B/opt/local/var/macports/build/_opt_local_var_macports_sources_macports.rsync.ionic.de_release_ports_lang_gcc46/gcc46/work/build/./gcc/
 -B/opt/local/x86_64-apple-darwin10/bin/ -B/opt/local/x86_64-apple-
 darwin10/lib/ -isystem /opt/local/x86_64-apple-darwin10/include -isystem
 /opt/local/x86_64-apple-darwin10/sys-include    -g -pipe -O2  -o
 libconftest.dylib -dynamiclib -Wl,-single_module conftest3.c
 }}}

 Gotcha, there we got the crash again. So it's definitely connected to the
 newly build libstdc++.

 Now, I replaced /usr/bin/ld with a script that calls /usr/bin/ld.orig (the
 original binary) and sends a SIGSTOP immediatly, which also enabled me to
 attach gdb to the process. Have a look at this:

 {{{
 (gdb) break malloc_error_break
 Breakpoint 2 at 0x3126e978c69499
 (gdb) cont
 Continuing.

 Program received signal SIGSTOP, Stopped (signal).
 0x00007fff5fc04f5f in
 __dyld__ZN4dyldL10loadPhase5EPKcRKNS_11LoadContextEPSt6vectorIS1_SaIS1_EE
 ()
 (gdb) cont
 Continuing.

 Program received signal SIGSTOP, Stopped (signal).
 0x00007fff5fc219d6 in __dyld_stat64 ()
 (gdb) cont
 Continuing.
 Reading symbols for shared libraries .+. done
 Breakpoint 3 at 0x100219c34: file new_allocator.h, line 98.
 Breakpoint 4 at 0x100219c64: file new_allocator.h, line 98.
 Breakpoint 5 at 0x10021b084: file new_allocator.h, line 98.
 Breakpoint 6 at 0x10021bab0: file new_allocator.h, line 98.
 Breakpoint 7 at 0x10021bac0: file new_allocator.h, line 98.
 Breakpoint 8 at 0x10021bc24: file new_allocator.h, line 98.
 Breakpoint 9 at 0x10021c2f4: file new_allocator.h, line 98.
 Breakpoint 10 at 0x10021cc3a: file new_allocator.h, line 98.
 warning: Multiple breakpoints were set.
 Use the "delete" command to delete unwanted breakpoints.
 Pending breakpoint 1 - "new_allocator.h:98" resolved

 Program received signal SIGSTOP, Stopped (signal).
 0x00007fff5fc0a2de in
 __dyld__ZL18gdb_image_notifier15dyld_image_modejPK15dyld_image_info ()
 (gdb) cont
 Continuing.

 Program received signal SIGSTOP, Stopped (signal).
 0x00007fff5fc1502f in
 __dyld__ZN26ImageLoaderMachOCompressed6rebaseERKN11ImageLoader11LinkContextE
 ()
 (gdb) cont
 Continuing.
 Reading symbols for shared libraries . done

 Breakpoint 9, std::string::assign (this=0x101777fa8, __str=<value
 temporarily unavailable, due to optimizations>) at new_allocator.h:98
 98            { ::operator delete(__p); }
 (gdb) print __p
 Cannot access memory at address 0x0
 }}}

 Something is really, really broken and upstream should fix that.

 However, I'll rebuild gcc45 and try to use that libstdc++ as that's the
 last known good version to me. We'll see.

-- 
Ticket URL: <https://trac.macports.org/ticket/27237#comment:14>
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