> Hi! > > The following patch adds a "redzone" clobber (recognized just > on targets which choose to recognize it, right now just x86), > with which one can mark the rare case where inline asm pushes > something on the stack or uses call instruction without taking > red zone into account (i.e. addq $-128, %rsp; and addq $128, %rsp > around that). > > 2024-11-06 Jakub Jelinek <ja...@redhat.com> > > gcc/ > * target.def (redzone_clobber): New target hook. > * varasm.cc (decode_reg_name_and_count): Return -5 for > "redzone". > * cfgexpand.cc (expand_asm_stmt): Handle redzone clobber. > * config/i386/i386.h (struct machine_function): Add > asm_redzone_clobber_seen member. > * config/i386/i386.cc (ix86_compute_frame_layout): Don't > use red zone if cfun->machine->asm_redzone_clobber_seen. > (ix86_redzone_clobber): New function. > (TARGET_REDZONE_CLOBBER): Redefine. > * doc/extend.texi (Clobbers and Scratch Registers): Document > the "redzone" clobber. > * doc/tm.texi.in: Add @hook TARGET_REDZONE_CLOBBER. > * doc/tm.texi: Regenerate. > gcc/testsuite/ > * gcc.target/i386/asm-redzone-1.c: New test.
LGTM, though if asm needs temporary memory it can ask for it explicitly. I guess this can be practical to hide actual call in the asm statement (which will break unwinding I guess). Honza
