On 15 May 2013 06:31, Ramana Radhakrishnan <ramana....@googlemail.com> wrote: > Sorry this had dropped off my list of patches to review somehow but > anyway here's a first cut review. > > On Thu, Mar 21, 2013 at 6:58 AM, Zhenqiang Chen > <zhenqiang.c...@linaro.org> wrote: >> Hi, >> >> When shrink-wrap is enabled, the "returns" from simple-return path and >> normal return path can be merged. The code is like: >> >> tst ... >> / \ >> | push ... >> | ... >> | pop ... >> \ / >> bx lr >> >> If the dwarf info after "pop ..." is incorrect, the dwarf checks will >> fail at dwarf2cfi.c: function maybe_record_trace_start. >> >> /* We ought to have the same state incoming to a given trace no >> matter how we arrive at the trace. Anything else means we've >> got some kind of optimization error. */ >> gcc_checking_assert (cfi_row_equal_p (cur_row, ti->beg_row)); >> >> The patch is to add epilogue dwarf info to make sure: >> >> Before "bx lr", >> * All registers saved in stack had been "restored". >> * .cfi_def_cfa_offset 0 >> * .cfi_def_cfa_register is sp even if frame_pointer_needed >> >> Boot strapped and no make check regression. > > in what configuration - thumb2 / arm / cortex-a15 / cortex-a9 ? what > languages and on what platform ?
Bootstrapped both arm and thumb2 on Pandaboard ES and Chromebook. Pandaboard ES (cortex-a9): --enable-languages=c,c++,fortran,objc,obj-c++ --with-arch=armv7-a --with-float=hard --with-fpu=vfpv3-d16 --enable-languages=c,c++,fortran,objc,obj-c++ --with-arch=armv7-a --with-float=hard --with-fpu=vfpv3-d16 --with-mode=thumb Chromebook (cortext-a15): --enable-languages=c,c++,fortran,objc,obj-c++ --with-arch=armv7-a --with-tune=cortex-a15 --with-float=hard --with-fpu=vfpv3-d16 --enable-languages=c,c++,fortran,objc,obj-c++ --with-arch=armv7-a --with-tune=cortex-a15 --with-float=hard --with-fpu=vfpv3-d16 --with-mode=thumb Regression tests on Pandborad ES for both arm and thumb2 with the same configure as bootstrap. >> >> Is it OK? > > >> @@ -25447,9 +25519,15 @@ arm_unwind_emit (FILE * asm_out_file, rtx insn) >> handled_one = true; >> break; > >> + /* The INSN is generated in epilogue. It is set as RTX_FRAME_RELATED_P >> + to get correct dwarf info for shrink-wrap. But We should not emit >> + unwind info for it. */ > > s/dwarf/debug frame. > > REplace "But We should not emit unwind info for it " with " We should > not emit unwind info for it because these are used either for pretend > arguments or <put the other case here>. " > > I think you are correct that there is no need for unwind information > as we only have unwind information valid at call points and in this > case I wouldn't expect unwind information to need to be exact for > pretend arguments Thanks for the comments. The patch is updated and rebased to trunk. -Zhenqiang
1-add-dwarf-info-on-epilogue.patch
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