Re: [PATCH] "$ gdb PROGRAM" vs "(gdb) file PROGRAM" difference; warn on failure to remove breakpoint.

[Yao Qi <yao@codesourcery.com>]

On 06/09/2014 10:22 PM, Pedro Alves wrote:
> And, likewise, "file" with no arguments only started turning
> breakpoints set in the main executable to "<pending>" with the
> remote-symbol-file patch (63644780).  The old behavior is now
  ^^^^^^ remove

I don't see breakpoint set in the main executable becomes "<pending>"
(with and without this patch applied), if the following steps are what
you meant.

(gdb) b main
Breakpoint 1 at 0x80484c1: file
../../../../git/gdb/testsuite/gdb.base/wchar.c, line 29.

(gdb) file
No executable file now.
Discard symbol table from
`/home/yao/Source/gnu/gdb/build-git/x86/gdb/testsuite/gdb.base/wchar'?
(y or n) y
Error in re-setting breakpoint 1: No symbol table is loaded.  Use the
"file" command.
No symbol file now.
(gdb) info breakpoints


Num     Type           Disp Enb Address    What


1       breakpoint     keep n   0x080484c1

> restored, and we break-unload-file.exp test now exercizes both "gdb;
> file PROGRAM" and "gdb PROGRAM".

Hope this table helps the understanding to the flags setting in
different scenarios:

shared library loaded by program   OBJF_SHARED
add-symbol-file foo                OBJF_SHARED | OBJF_USERLOADED
symbol-file or file foo            OBJF_USERLOADED
./gdb foo                          Neither

> @@ -7729,18 +7729,19 @@ disable_breakpoints_in_freed_objfile (struct objfile *objfile)
>    if (objfile == NULL)
>      return;
>  
> -  /* OBJF_USERLOADED are dynamic modules manually managed by the user
> -     with add-symbol-file/remove-symbol-file.  Similarly to how
> -     breakpoints in shared libraries are handled in response to
> -     "nosharedlibrary", mark breakpoints in OBJF_USERLOADED modules
> +  /* OBJF_SHARED|OBJF_USERLOADED objfiles are dynamic modules manually
> +     managed by the user with add-symbol-file/remove-symbol-file.
> +     Similarly to how breakpoints in shared libraries are handled in
> +     response to "nosharedlibrary", mark breakpoints in such modules

The comments are clear to me...

>       shlib_disabled so they end up uninserted on the next global
>       location list update.  Shared libraries not loaded by the user
>       aren't handled here -- they're already handled in
>       disable_breakpoints_in_unloaded_shlib, called by solib.c's
>       solib_unloaded observer.  We skip objfiles that are not
> -     OBJF_USERLOADED (nor OBJF_SHARED) as those aren't considered
> -     dynamic objects (e.g. the main objfile).  */
> -  if ((objfile->flags & OBJF_USERLOADED) == 0)
> +     OBJF_SHARED as those aren't considered dynamic objects (e.g. the
> +     main objfile).  */
> +  if ((objfile->flags & OBJF_SHARED) == 0
> +      || (objfile->flags & OBJF_USERLOADED) == 0)
>      return;

... these are clear too, but shouldn't we only check
"(objfile->flags & OBJF_SHARED) == 0" here? which means objfile is a
shared library loaded by program or is added by add-symbol-file can
be processed afterwards.

-- 
Yao (齐尧)