Won't be able to look at it till later in the afternoon . got a few other things to finish up during the day.
Ramana
-----Original Message----- From: Zhenqiang Chen [mailto:zhenqiang.chen@linaro.org] Sent: 16 October 2012 08:44 To: Ramana Radhakrishnan Cc: linaro-toolchain Subject: Re: Add dwarf/unwind info in epilogue
On 16 October 2012 14:58, Ramana Radhakrishnan Ramana.Radhakrishnan@arm.com wrote:
shrink-wrap.patch doesn't apply cleanly to the revision you suggest.
If you give a clean patch and some description of what happens I might be able to take a look ..
Please try the new one. With the patch, your build might fail when build libraries.
internal compiler error: in maybe_record_trace_start, atdwarf2cfi.c:2224
To get a toolchain, just remove the line at dwarf2cfi.c:2224.
gcc_checking_assert (cfi_row_equal_p (cur_row, ti->beg_row));After build OK. Re add the line at dwarf2cfi.c:2224 and make install.
What do you expect to happen with the testcases ? ICE ? wrong-code ,
wrong-debug info, what ?
All cases will be ICE due to wrong debug info. My option is: -mthumb -mcpu=cortex-m3 -O2 -g For all cases, it will ICE.
internal compiler error: in maybe_record_trace_start, at dwarf2cfi.c:2224
The root cause: Without shrink-wrap, the code is like
push ... pop return //The return has only one predecessor. No dwarf check for this case, even if the dwarf info is wrong.
With shrink-wrap, the basic code is like
tst ... L1 push ... pop return // no dwarf check for it L1: simple_return // no dwarf check for it
After some optimization the code is like
tst ... L1 push ... pop // ************The return is optimized ********* L1: simple_return //Now the simple_return has two predecessors. dwarf check fail at this block if the debug info is wrong.
Thanks! -Zhenqiang
From: Zhenqiang Chen [zhenqiang.chen@linaro.org] Sent: 16 October 2012 04:44 To: Ramana Radhakrishnan Cc: linaro-toolchain Subject: Re: Add dwarf/unwind info in epilogue
On 16 October 2012 10:22, Ramana Radhakrishnan ramana.radhakrishnan@arm.com wrote:
Zhenqiang,
I've been spending sometime scratching my head around this one
tonight. Can you show me the original shrink-wrap patch as well the test case that triggers this failure ? I have my suspicion on something but need to run a few experiments before commenting further.
p4.patch is from the mail-list discussion: http://old.nabble.com/Shrink-wrapping%3A-Introduction-to31220423.html
shrink-wrap.patch is my patch against r192445.
*.c are test cases: -O2 -g
There is no fail in gcc-linaro-4.5 since "simple_return" and "normal return" can not be optimized as one common return.
Thanks! -Zhenqiang
On 15 Oct 2012, at 10:57, Zhenqiang Chen zhenqiang.chen@linaro.org
wrote:
Hi Ramana,
The attached file is a reference patch to add more dwarf/unwind
info
in epilogue. Please help to review.
Without the patch, dwarf check fail for the following cases when enabling shrink-wrap:
tst ... L1 //simple_return push ... ... pop ... //.cfa_offset is not 0 L1: bx lr //common simple_return
Thanks!
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