On 05/16/13 07:27, Zhenqiang Chen wrote:
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.
Ok if no regressions.
regards
Ramana
-Zhenqiang
