[fpc-devel] FPC SVN 8427 : GDB/DWARF2 issues

[Marc Weustink]

Bruce Tulloch wrote:
> I should note here that the strange anomalies I reported below do not
> occur when using stabs instead of dwarf2.
> 
> That is, gdb knows the language is pascal regardless of the source file
> location and it never shows the file name with any path prepended. Stabs
> data also mangles the method symbol names to show their classes whereas
> dwarf2 does not (indeed dwarf2 knows nothing about classes in gdb).

Dwarf support in GDB was/is very minimalistic. You can try to compile 
with -gw3 to enable the full dwarf 3 specs, but the last time I tried 
GDB didn't understand it.

> Bruce Tulloch wrote:
>> The first strange thing to notice is that the current source file still
>> has a path prepended (as reported by GDB) if the source file is not in
>> the working directory (ie, the "/home/bruce/vc/src//" shown above).
>>
>> The second strange thing is that gdb's "info source" reports
>>
>>   Source language is minimal.
>>   Compiled with DWARF 2 debugging format.
>>   Does not include preprocessor macro info.
>>
>> when viewing source which is in the current working directory but:
>>
>>   Source language is pascal.
>>   Compiled with unknown debugging format.
>>   Does not include preprocessor macro info.
>>
>> when viewing source which is located elsewhere. It seems gdb understands
>> that it's reading DWARF2 but not that the language is pascal if the file
>> is in the working directory and vice versa if the file is elsewhere.

Somehow it doesnt surprise me.

Marc


>>
>> So far these issues appear benign for our purposes here, but presumably
>> they indicate something is still amiss?
>>
>> Another clue may be complaints by readelf -wl which reports:
>>
>> "Warning: The line info appears to be corrupt - the section is too small"
>>
>> I hope this helps. We will feedback more as we discover stuff.
>>
>> Cheers, Bruce.
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