https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105599
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by Iain D Sandoe <ia...@gcc.gnu.org>: https://gcc.gnu.org/g:58c0bc2b62cdbbe9d9677b448fe52a8c54044276 commit r12-8484-g58c0bc2b62cdbbe9d9677b448fe52a8c54044276 Author: Iain Sandoe <i...@sandoe.co.uk> Date: Sun May 29 16:14:32 2022 +0100 Darwin: Fix empty g++ command lines [PR105599]. An empty g++ command line should produce a diagnostic that there are no inputs. The PR is that currently Darwin produces a dignostic about missing link items instead - this is because (errnoeously), for this driver, we are creating a link job for empty command lines. The problem occurs in four stages: The g++ driver appends -shared-libgcc to the command line. The Darwin driver_init code in the backend does not see this (it sees an empty command line). When the back end driver code driver sees an empty command line, it does not add any supplementary flags (e.g. asm-macosx-version-min) - precisely to avoid anything being claimed as an input_file and therefore triggering a link line. Since we do not have a value for asm-macosx-version-min when processing the driver specs, we unconditionally inject 'multiply_defined suppress' which is used with shared libgcc (but only intended on very old Darwin). This then causes the generation of a link job. The solution, for the present, is to move version-specific link params to the LINK_SPEC so that they are only processed when a link job has already been decided. Signed-off-by: Iain Sandoe <i...@sandoe.co.uk> PR target/105599 gcc/ChangeLog: * config/darwin.h: Move versions-specific handling of multiply_defined from SUBTARGET_DRIVER_SELF_SPECS to LINK_SPEC. (cherry picked from commit 794737976b9a6418eab817f143bb4eb2d0c834d2)
