Re: setting a breakpoint on a dll, relative path or absolute path issue

[asmwarrior <asmwarrior@gmail.com>]

On 2011-6-11 22:25, Earnie wrote:
> asmwarrior wrote:
>> The strange thing is:
>> when I pass a true path
>> "E:\code\cb\wx\wxWidgets-2.8.12\src/common/string.cpp", then the
>> breakpoint failed, gdb report that there is no such source file.
>>
>> But when using "../../src/common/datetime.cpp" or
>> "E:\code\cb\wx\wxWidgets-2.8.12\build\msw/../../src/common/string.cpp",
>> the breakpoint can be set correctly.
>>
>> So, can some gdb developers can tell the truth why this would happen?
>> I think at least when using
>> "E:\code\cb\wx\wxWidgets-2.8.12\src/common/string.cpp", the breakpoint
>> should set correctly.
>>
>
> I'm not a gdb developer nor do I use it often but I'm of the opinion
> that gdb isn't looking on disk for the file and is looking instead for a
> match in a record in the object data.  Does it help if you use the
> --directory=/path/to/source/files switch?

My dll was located in:
E:\code\cb\wx\wxWidgets-2.8.12\lib\gcc_dll\wxmsw28ud_gcc_custom.dll
and when build this dll, I use the make file locates in:
E:\code\cb\wx\wxWidgets-2.8.12\build\msw\makefile.gcc
and all the sources were under:
E:\code\cb\wx\wxWidgets-2.8.12\src

I have manually add the directory by using those command:
dir E:/code/cb/wx/wxWidgets-2.8.12/build/msw
dir E:/code/cb/wx/wxWidgets-2.8.12/src
dir dir E:/code/cb/wx/wxWidgets-2.8.12/lib/gcc_dll

and now, I try to set a break point:
 > break "E:/code/cb/wx/wxWidgets-2.8.12/src/common/string.cpp:164"
No source file named E:/code/cb/wx/wxWidgets-2.8.12/src/common/string.cpp.
Breakpoint 3 ("E:/code/cb/wx/wxWidgets-2.8.12/src/common/string.cpp:164) 
pending.

Which means: passing the absolute path still failed.

------------------------------------------------------------

The strange thing is that passing a relative path works
 > break "../../src/common/string.cpp:164"
Breakpoint 4 at 0x66d89f44: file ../../src/common/string.cpp, line 164.

This means that gdb internally know this relative path matches some 
debugging symbols.

The more strange thing is, if the path was supplied by this:
 >>>>>>cb_gdb:
 > break 
E:\code\cb\wx\wxWidgets-2.8.12\build\msw/../../src/common/string.cpp:164
Breakpoint 2 at 0x66d89f44: file ../../src/common/string.cpp, line 164.

 >>>>>>cb_gdb:
 > break 
E:\code\cb\wx\wxWidgets-2.8.12\src\common/../../src/common/string.cpp:165
No source file named 
E:\code\cb\wx\wxWidgets-2.8.12\src\common/../../src/common/string.cpp.
Breakpoint 3 
(E:\code\cb\wx\wxWidgets-2.8.12\src\common/../../src/common/string.cpp:165) 
pending.

 >>>>>>cb_gdb:
 > break 
E:\code\cb\wx\wxWidgets-2.8.12\lib\gcc_dll/../../src/common/string.cpp:165
No source file named 
E:\code\cb\wx\wxWidgets-2.8.12\lib\gcc_dll/../../src/common/string.cpp.
Breakpoint 4 
(E:\code\cb\wx\wxWidgets-2.8.12\lib\gcc_dll/../../src/common/string.cpp:165) 
pending.
 >>>>>>cb_gdb:

You can see: if the relative path is followed by
E:\code\cb\wx\wxWidgets-2.8.12\build\msw
the breakpoint can be set correctly.

If the relative path is followed by some other path like:
E:\code\cb\wx\wxWidgets-2.8.12\src\common
or
E:\code\cb\wx\wxWidgets-2.8.12\lib\gcc_dll
The breakpoint can't be set.

>
>> Can you give me a direction that I can dig into the gdb's source?
>
> Sorry, no, debugging the debugger is an awesome task and one I've never
> desired to do. Good luck on your journey into this venture, I truly wish
> you well.  There has been little development in gdb on Windows that I
> know of and it would be good if someone had the heart to put some love
> into it.
>
thanks for the encourage, and I will do my best to contribute.

asmwarrior
ollydbg from codeblocks' forum