Re: [PATCH] obvious pattern fix in gdb.base/step-line.exp

[Christophe LYON <christophe.lyon@st.com>]

Hello Joel,

On 27.03.2009 19:47, Joel Brobecker wrote:
> Hello Christophe,
> 
>> 2009-03-27  Christophe Lyon  <christophe.lyon@st.com>
>>
>> 	testsuite/
>> 	* gdb.base/step-line.exp: Fix pattern to allow full path before
>> 	"step-line.c".
> 
> I'd love to have some feedback from the other maintainers on this one.
> 
> My first observation is that it doesn't fail for me when testing
> out-of-tree, using either DWARF or stabs. So I'm wondering why
> this is failure in Chistophe's case. Perhaps a dump of your debugging
> information (filename/dirname info for step-line.c and the line table
> as well) would allows to understand the difference.
> 
> That being said, I don't see that we make a guaranty at the user-level
> that the name of the file will be printed using either its full path or
> just the basename, or anthing in the middle.  So we could argue that
> the output with the full path is equally valid and that the expected
> output should therefore be enhanced to accept both.
> 
> WDYT?

I forgot to mention that before submitting the patch, I grepped in 
gdb.base and gdb.cp to see how other tests expect the filename to be 
printed. Maybe I missed some of them, but I noticed that step-line.c was 
the only one not using .*$srcfile.

So I thought it had been forgotten.


Yet, this is not an explanation of why it fails :-)
I am not using GCC, but a retargetting of Open64 for one of our internal 
targets. Maybe people from Tensilica or PathScale have already noticed 
the same issue.

If I dump the Dwarf info (using dwarfdump and readelf), I can see the 
full path name in DW_AT_name for the compile_unit (I tried to call 
runtest with absolute and relative --srcdir, and in both cases the test 
fails).
For DW_AT_comp_dir, I have the expected hostname:absolute_path string.

Comparing with GCC, there is a difference in the DW_AT_comp_dir, where 
GCC does not print the hostname prefix. But my understanding of the 
Dwarf spec is that hostname:path should be used, isn't it? Anyway GDB 
seems to be able to cope with this (see read_file_scope in 
dwarf2read.c). Still with GCC, I notice that if I use an absolute source 
file name, there is no DW_AT_comp_dir.

To summarize, when using an absolute src file name:
* GCC:
DT_AT_name=absolute src file name
DW_AT_comp_dir: not present
Directory table in debug_line: absolute path to `dirname $srcfile`
  The File Name Table:
   Entry Dir     Time    Size    Name
   1     1       0       0       step-line.c
   2     0       0       0       step-line.c
   3     0       0       0       step-line.inp

* Open64:
DT_AT_name=absolute src file name
DW_AT_comp_dir=hostname:absolute `pwd`
Directory table in debug_line:
  - absolute path to `dirname $srcfile`
  - absolute `pwd`
The File Name Table:
   Entry Dir     Time    Size    Name
   1     1       0       0       step-line.c
   2     2       0       0       step-line.inp

So... it may be an issue with my compiler handling of #line?


Thanks,

Christophe.