Re: LTO symtab sections vs. missing symbols (libcalls maybe?) and lto-plugin vs. COFF

[Dave Korn <dave dot korn dot cygwin at gmail dot com>]

On 14/10/2010 19:11, Ian Lance Taylor wrote:
> Dave Korn writes:
> 
>>   The consequence of this is that either there are going to be undefined
>> symbols in the final executable, or the linker has to perform another round of
>> library scanning.  It occurred to me that the semantics of this might even not
>> have been decided yet, since ELF platforms are perfectly happy with undefined
>> symbols at final link time.
> 
> Only when linking dynamically, though.  This suggests that your test
> case should fail on ELF when linking with -static.  If not, why not?
> 
> Ian

  My testcase was pretty much just hello world, and the reason it wouldn't
fail on ELF with -static is because:

>     %{fuse-linker-plugin: \
>     -plugin %(linker_plugin_file) \
>     -plugin-opt=%(lto_wrapper) \
>     -plugin-opt=-fresolution=%u.res \
>     %{static|static-libgcc:-plugin-opt=-pass-through=%(lto_libgcc)}	\
>     %{static:-plugin-opt=-pass-through=-lc}	\
>     } \

... -lc gets added back in right at the very end of the link, thanks to that
pass-through option.

  What I'm planning on COFF is to figure a way to add further pass-through
options for all the -l options and .a files in LIB_SPEC.

    cheers,
      DaveK