Enabling LTO for target libraries (e.g., libgo, libstdc++)

[Richard Biener]

On January 25, 2019 6:17:54 PM GMT+01:00, Joseph Myers <joseph@codesourcery.com> wrote:
>On Fri, 25 Jan 2019, Nikhil Benesch wrote:
>
>> I am attempting to convince GCC to build target libraries with
>link-time
>> optimizations enabled. I am primarily interested in libgo, but this
>discussion
>
>Note that as far as I know issues with host-dependencies of LTO
>bytecode 
>(bug 41526) may still exist, so this wouldn't work with Canadian cross 
>compilers.

I was expecting the LTO byte code not to be retained in the built libraries. 

>> I have a simple patch to the top-level configure.ac that resolves the
>issue by
>> teaching the build system to use the gcc-ar and gcc-ranlib wrappers
>which were
>> built earlier and know how to pass the linker plugin to the
>underlying ar/ranlib
>> commands. The patch is small enough that I've included it at the end
>of this
>> email.
>
>Will those wrappers properly wrap round tools for the target that were 
>configured using --with-build-time-tools?