[PATCH] Recognize branch instruction on MIPS in gdb.trace/entry-values.exp

Yao Qi yao@codesourcery.com
Tue Dec 30 12:34:00 GMT 2014


"Maciej W. Rozycki" <macro@codesourcery.com> writes:

>  What's the semantics of the test case and the changes you're making?  
>

dwarf assembler is used to generate debug info with DW_TAG_GNU_call_site
and DW_TAG_GNU_call_site_parameter to exercise GDB.  The change I am
making in this patch is to recognize branch instruction on MIPS, so that
we can compute the address returned from foo, and fill it in the
generated debug info.

>  I'm asking because the MIPS architecture has several instructions used to 
> make procedure calls, depending on the ISA and ABI selected, and also 
> compiler options.  Besides JAL these instructions include JALS, JALX, 
> JALR, JALRC, JALRS, BAL and BALS.  It looks to me you need to modify the 
> pattern here to take these into account; JALRC does not have a delay slot.
>

I'll update the pattern to {jalrc|(?:jal|bal)[^\r\n]+\r\n}

>> All tests in entry-values.exp are PASS.
>
>  Which target and ABI(s) did you ran your testing on?  Please try at least 
> these: o32/MIPS, o32/MIPS16, o32/microMIPS, n64 on a Linux and a 
> bare-metal target each; testing o32/MIPS16 with the `-mflip-mips16' GCC 
> option too will be appreciated.  These combinations should trigger some 
> (although not all) of the other possible instructions.

To avoid of misunderstanding, let me map them to the following concrete gcc
options (I don't find -mabi=o32 nor -mabi=n64 in
https://gcc.gnu.org/onlinedocs/gcc/MIPS-Options.html),

  -mabi=32 
  -mabi=32 -mips16
  -mabi=32 -mips16 -mflip-mips16
  -mabi=32 -mmicromips
  -mabi=64 on both linux and bare-metal target

are they what you want?

-- 
Yao (齐尧)



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