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 ? > > 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 Ramana
