Re: PATCH gas -gstabs : add cwd

["Philippe De Muyter" <phdm at macqel dot be>]

Nick Clifton wrote :
> Hi Philippe,
> 
> > Below is a little patch I needed to make when debugging asm files with gdb :
> > It adds the compilation directory in the stabs info, just like gcc does.
> 
> > 2003-10-01  Philippe De Muyter  <phdm@macqel.be>
> >
> > 	* stabs.c (stabs_generate_asm_file) : Add the compilation directory
> > 	to the stabs debug info.
> 
> Thanks for submitting this patch.  There are a couple of problems with
> it however:
> 
>   * Adding a compilation directory stab entry is a GNU extension to
>     the STABS specificiation, so really there needs to be a command
>     line option to control whether it used or not.

OK, I now add the `--gstabs+' option, like the gcc one.

> 
>   * You code should follow the GNU Coding standards.  In the case of
>     your patch there needs to be a single space between the name of a
>     function and its opening parenthesis.

How could I forgot that :) ?

> 
>   * Choosing the current directory as the source directory for the
>     file is not necessarily the best thing to do.  I think that it
>     would be worthwhile attempting to extract the directory from the
>     filename, if possible.

I don't think that that's worth the work, and that would be different from
what gcc does.  I prefer to keep it identical to gcc's behaviour.

> 
>   * The specification for getcwd() says that if the buffer pointer is
>     NULL then its behaviour is undefined.  It would be better to use
>     the getpwd() function provided by the libiberty library.

OK, fixed.

> 
> Cheers
>         Nick
> 

So here is the revised patch, including a documentation part.

Philippe

2003-10-07  Philippe De Muyter  <phdm@macqel.be>

	* as.c (use_gnu_debug_info_extensions) : New variable. 
	(parse_args) : Accept new --gstabs+ option, and set
	`use_gnu_debug_info_extensions'.
	(show_usage) : Document --gstabs+ option.
	* as.h (use_gnu_debug_info_extensions) : New extern declaration.
	* stabs.c (stabs_generate_asm_file) : If
	`use_gnu_debug_info_extensions' is set, add the compilation
	directory to the stabs debug info.
	* doc/as.texinfo : Document --gstabs+ option.

Index: as.c
===================================================================
RCS file: /cvs/src/src/gas/as.c,v
retrieving revision 1.49
diff -u -w -p -r1.49 as.c
--- as.c	5 Oct 2003 08:58:01 -0000	1.49
+++ as.c	7 Oct 2003 21:26:34 -0000
@@ -87,6 +87,7 @@ int listing;
 
 /* Type of debugging to generate.  */
 enum debug_info_type debug_type = DEBUG_UNSPECIFIED;
+int use_gnu_debug_info_extensions = 0;
 
 /* Maximum level of macro nesting.  */
 int max_macro_nest = 100;
@@ -276,6 +277,8 @@ Options:\n\
   fprintf (stream, _("\
   --gstabs                generate stabs debugging information\n"));
   fprintf (stream, _("\
+  --gstabs+               generate stabs debug info with GNU extensions\n"));
+  fprintf (stream, _("\
   --gdwarf2               generate DWARF2 debugging information\n"));
   fprintf (stream, _("\
   --help                  show this message and exit\n"));
@@ -403,6 +406,7 @@ parse_args (int * pargc, char *** pargv)
       OPTION_LISTING_CONT_LINES,
       OPTION_DEPFILE,
       OPTION_GSTABS,
+      OPTION_GSTABS_PLUS,
       OPTION_STRIP_LOCAL_ABSOLUTE,
       OPTION_TRADITIONAL_FORMAT,
       OPTION_GDWARF2,
@@ -442,6 +446,7 @@ parse_args (int * pargc, char *** pargv)
     {"listing-cont-lines", required_argument, NULL, OPTION_LISTING_CONT_LINES},
     {"MD", required_argument, NULL, OPTION_DEPFILE},
     {"gstabs", no_argument, NULL, OPTION_GSTABS},
+    {"gstabs+", no_argument, NULL, OPTION_GSTABS_PLUS},
     {"strip-local-absolute", no_argument, NULL, OPTION_STRIP_LOCAL_ABSOLUTE},
     {"traditional-format", no_argument, NULL, OPTION_TRADITIONAL_FORMAT},
     {"gdwarf2", no_argument, NULL, OPTION_GDWARF2},
@@ -643,6 +648,9 @@ the GNU General Public License.  This pr
 	  start_dependencies (optarg);
 	  break;
 
+	case OPTION_GSTABS_PLUS:
+	  use_gnu_debug_info_extensions = 1;
+	  /* Fall thru */
 	case OPTION_GSTABS:
 	  debug_type = DEBUG_STABS;
 	  break;
Index: as.h
===================================================================
RCS file: /cvs/src/src/gas/as.h,v
retrieving revision 1.33
diff -u -w -p -r1.33 as.h
--- as.h	4 Jun 2003 16:54:45 -0000	1.33
+++ as.h	7 Oct 2003 21:26:35 -0000
@@ -476,6 +476,7 @@ enum debug_info_type {
 };
 
 extern enum debug_info_type debug_type;
+extern int use_gnu_debug_info_extensions;
 
 /* Maximum level of macro nesting.  */
 extern int max_macro_nest;
Index: stabs.c
===================================================================
RCS file: /cvs/src/src/gas/stabs.c,v
retrieving revision 1.20
diff -u -w -p -r1.20 stabs.c
--- stabs.c	27 May 2003 19:19:29 -0000	1.20
+++ stabs.c	7 Oct 2003 21:26:36 -0000
@@ -502,6 +502,15 @@ stabs_generate_asm_file ()
   unsigned int lineno;
 
   as_where (&file, &lineno);
+  if (use_gnu_debug_info_extensions)
+    {
+      char *dir, *dir2;
+
+      dir = getpwd ();
+      dir2 = alloca (strlen (dir) + 2);
+      sprintf (dir2, "%s%s", dir, "/");
+      generate_asm_file (N_SO, dir2);
+    }
   generate_asm_file (N_SO, file);
 }
 
Index: doc/as.texinfo
===================================================================
RCS file: /cvs/src/src/gas/doc/as.texinfo,v
retrieving revision 1.91
diff -u -w -p -r1.91 as.texinfo
--- doc/as.texinfo	30 Sep 2003 16:17:13 -0000	1.91
+++ doc/as.texinfo	7 Oct 2003 21:26:48 -0000
@@ -263,8 +263,8 @@ gcc(1), ld(1), and the Info entries for 
 @smallexample
 @c man begin SYNOPSIS
 @value{AS} [@b{-a}[@b{cdhlns}][=@var{file}]] [@b{-D}] [@b{--defsym} @var{sym}=@var{val}]
- [@b{-f}] [@b{--gstabs}] [@b{--gdwarf2}] [@b{--help}] [@b{-I} @var{dir}] 
- [@b{-J}] [@b{-K}] [@b{-L}]
+ [@b{-f}] [@b{--gstabs}] [@b{--gstabs+}] [@b{--gdwarf2}] [@b{--help}]
+ [@b{-I} @var{dir}] [@b{-J}] [@b{-K}] [@b{-L}]
  [@b{--listing-lhs-width}=@var{NUM}] [@b{--listing-lhs-width2}=@var{NUM}]
  [@b{--listing-rhs-width}=@var{NUM}] [@b{--listing-cont-lines}=@var{NUM}]
  [@b{--keep-locals}] [@b{-o} @var{objfile}] [@b{-R}] [@b{--statistics}] [@b{-v}]
@@ -514,6 +514,13 @@ compiler output).
 Generate stabs debugging information for each assembler line.  This
 may help debugging assembler code, if the debugger can handle it.
 
+@item --gstabs+
+Generate stabs debugging information for each assembler line, with GNU
+extensions that probably only gdb can handle, and that could make other
+debuggers crash or refuse to read your program.  This
+may help debugging assembler code.  Currently the only GNU extension is
+the location of the current working directory at assembling time.
+
 @item --gdwarf2
 Generate DWARF2 debugging information for each assembler line.  This
 may help debugging assembler code, if the debugger can handle it.  Note---this
@@ -4326,7 +4333,7 @@ in @sc{ieee} format.
 @cindex @code{func} directive
 @code{.func} emits debugging information to denote function @var{name}, and
 is ignored unless the file is assembled with debugging enabled.
-Only @samp{--gstabs} is currently supported.
+Only @samp{--gstabs[+]} is currently supported.
 @var{label} is the entry point of the function and if omitted @var{name}
 prepended with the @samp{leading char} is used.
 @samp{leading char} is usually @code{_} or nothing, depending on the target.