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Re: [PATCH] testsuite/gdb.dwarf2: Fix for dw2-ifort-parameter failure on ARM
- From: Omair Javaid <omair dot javaid at linaro dot org>
- To: Yao Qi <yao at codesourcery dot com>
- Cc: gdb-patches at sourceware dot org, Patch Tracking <patches at linaro dot org>
- Date: Tue, 1 Oct 2013 14:53:11 +0500
- Subject: Re: [PATCH] testsuite/gdb.dwarf2: Fix for dw2-ifort-parameter failure on ARM
- Authentication-results: sourceware.org; auth=none
- References: <CANW4E-2bQYjx6YdR3qGyKUsQa_KOrtmkWsZYqKzcuQBF==RPpw at mail dot gmail dot com> <CANW4E-25HdXYKMk258iO=GZ=PNM=Zu4jMbstpkSoMgE9wFpmkQ at mail dot gmail dot com> <51E4B587 dot 70007 at codesourcery dot com> <CANW4E-0vd51dTvd5qxUbeDn7ebXV-cf+WS4+VpyyGyD0MYGk8Q at mail dot gmail dot com>
On 19 September 2013 20:30, Omair Javaid <omair.javaid@linaro.org> wrote:
> Yao,
>
> Thanks for your feedback.
>
> Here is the testcase without my patch and breakpoint address gets
> adjusted because an odd address was being used:
>
> (gdb) break func
> warning: Breakpoint address adjusted from 0x000083bd to 0x000083bc.
> Breakpoint 1 at 0x83bc (2 locations)
> (gdb) run
> Starting program:
> /home/linaro/omair/bug_triage/gdb-7.6/gdb/testsuite/gdb.dwarf2/dw2-ifort-parameter
> warning: Breakpoint address adjusted from 0x000083bd to 0x000083bc.
> warning: Breakpoint address adjusted from 0x000083bd to 0x000083bc.
> warning: Breakpoint address adjusted from 0x000083bd to 0x000083bc.
> warning: Breakpoint 1 address previously adjusted from 0x000083bd to 0x000083bc.
>
> Breakpoint 1, 0x000083bc in func ()
> (gdb) p/x param
> No symbol "param" in current context.
> (gdb) FAIL: gdb.dwarf2/dw2-ifort-parameter.exp: p/x param
> testcase ./gdb.dwarf2/dw2-ifort-parameter.exp completed in 0 seconds
>
> Can you suggest any other way to fix this issue.
>
> Thanks you for you help.
>
>
> --
> Omair.
>
> On 16 July 2013 03:52, Yao Qi <yao@codesourcery.com> wrote:
>> On 07/15/2013 06:25 PM, Omair Javaid wrote:
>>>
>>> gdb.dwarf2/dw2-ifort-parameter fails on ARM because the dwarf2 debug
>>> information being created by gdb.dwarf2/dw2-ifort-parameter-debug.S
>>> gets corrupted because LSB of function addresses is ON in Thumb mode.
>>> ARM instructions are word aligned and LSB of instruction address is
>>> used to determine whether code being branched to is Thumb or ARM code.
>>> This patch solves the problem by decrementing function address by one
>>> in thumb mode. This patch has been tested on x86_64 and arm7 machines.
>>
>>
>> Omair,
>> IMO, the last bit of "function pointer value" indicates whether the target
>> function is an ARM or a thumb one. The "address" should still refer to the
>> actual address, as "DWARF should tell the truth". What is wrong *without*
>> your patch?
>>
>> --
>> Yao (éå)
Ping? Any suggestions? I can actually add labels in c code of this
test case and use those labels instead of function pointer values.
Would that be fine?