Re: Path handling bug in GDB included with MingW 3.1.0-1

[Chris Johns <cjohns@cybertec.com.au>]

Eli Zaretskii wrote:
>>From: "Michael Stather" <michaelstather@nuzi.de>
>>Date: Sun, 5 Oct 2003 23:48:35 +0200
>>
>>g++ -g -o p.exe c:/p/p.cpp -mwindows
>>gdb
>>break "c:/p/p.cpp:7"
>>Run
>>
>>gdb won?t stop at the breakpoint.
>>however if I do:
>>
>>cd c:\m

Not sure if this is suppose to be 'm' or 'p' and if this makes a difference.

>>g++ -g -o p.exe p.cpp -mwindows
>>gdb
>>break "p.cpp:7"
>>run
>>
>>it breaks correctly.
> 
> 
> Sounds like the MinGW port isn't writing leading directories of the
> files into the debug info.
> 

The 5.2.1-1 patch for MinGW stripped a leading '/' from a path for some 
reason.

> Questions:
> 
> What is the default debug info format used by the MinGW port of GCC?

stabs

> 
> Does it help to use -gstabs+ instead of just -g?
> 

No change the trace below.

> Do you see the leading directories of the source file names if you
> run "objdump --debug" on the object files?

I tried the 20030930 snapshot with a new MinGW patch the other day and I 
could set the break point and gdb stopped. I posted this result to the 
MinGW mailing list.

I decided to try gdb 6.0. This is what I have found with a simple hello 
world compiled with:

  > g++ -g -o p p.cpp -mwindows

and gdb run in a cmd box on XP:

  (gdb) info files
  Symbols from "C:\p/p.exe".
  Local exec file:
          `C:\p/p.exe', file type pei-i386.
          Entry point: 0x401000
          0x00401000 - 0x00433300 is .text
          0x00434000 - 0x00435234 is .data
          0x00436000 - 0x0043a9e0 is .bss
          0x0043b000 - 0x0043b7f4 is .idata
  (gdb) b "c:\p/p.cpp:6"
  Internal: readin p.cpp pst for `c:\p/p.cpp' found when no symtab found.
  (gdb) b "c:/p/p.cpp:6"
  Breakpoint 1 at 0x4012da: file p.cpp, line 6.
  (gdb) b "c:\p\p.cpp:6"
  No source file named c:\p\p.cpp.
  (gdb) b "p.cpp:6"
  Note: breakpoint 1 also set at pc 0x4012da.
  Breakpoint 2 at 0x4012da: file p.cpp, line 6.
  (gdb) maintenance info symtabs
  { objfile C:\p/p.exe ((struct objfile *) 010EFB00)
    { symtab p.cpp ((struct symtab *) 011A1D00)
      dirname C:/p/
      fullname C:/p/p.cpp
      blockvector ((struct blockvector *) 01193D10) (primary)
      debugformat stabs
    }
   [snip]

The MinGW patch I used is on SF under the MinGW project. It contains no 
changes to the source file or symbol handling in GDB.

-- 
  Chris Johns, cjohns at cybertec.com.au