[En-Nut-Discussion] arm-none-eabi-gcc, mtpcs-leaf-frame and cortex_debug.c

[Uwe Bonnes]

>>>>> "Ole" == Ole Reinhardt <ole.reinhardt at embedded-it.de> writes:

    Ole> Hi Uwe, this question is yet quite old, but let me answer anyway.

    Ole> Am 30.03.2015 11:19, schrieb Uwe Bonnes:
    >> your patch: Added experimental stack backtrace code, which can be
    >> enabled for easier debugging exceptions.  introduces
    >> -mtpcs-leaf-frame as compiler option.
    >> 
    >> On Cortex-M0, this caused a compiler error. So I opened
    >> https://bugs.launchpad.net/gcc-arm-embedded/+bug/1390053
    >> 
    >> This bug was pending for some time and asking again these days the
    >> response was a status change to: Confirmed → Won't Fix
    >> 
    >>> We are going to deprecate all TPCS related options
    >>> https://gcc.gnu.org/gcc-5/changes.html. So please try not using
    >>> them.
    >> 
    >> Any ideas how to get around that?

    Ole> Unfortunately not. As Cortex Mx CPUs do not have a dedicated frame
    Ole> pointer which gets stacked on a function call, we are not able to
    Ole> do a real stack backtrace. The problem is, that you do not know at
    Ole> which position your last stack frame starts.

https://gcc.gnu.org/ml/gcc-help/2015-05/msg00080.html
tells

> I don't expect -mapcs-frame to go away any time soon.

But the bug with Cortex M0(Plus) is still there. I will try to bug the
cortex arm gcc develoopers again.

Bye
-- 
Uwe Bonnes                bon at elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
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