[RFC-2] Handle GPC specific name for main function

["Pierre Muller" <muller@ics.u-strasbg.fr>]

  I updated my patch according to the comments from
Eli and Joel. Thanks to both.
 
  Eli, I added a comment in p-lang.c
that is not really conform to standards, but 
the whole file uses similar comments.
Should I reformat them? In a separate patch?

  To GPC developers:
   there is a blank in the patch:
Joel proposed to tell up to which version of
GPC, the old name was used.
  I have no idea about that, could someone
please tell me.
  By the way, is there some publically
readable CVS tree for GPC sources?

  As stated in a previous email, the patch
does not seem to generate new failures
in the testsuite.

Pierre

ChangeLog entry:

2007-09-26  Pierre Muller  <muller@ics.u-strasbg.fr>

        * p-lang.h (pascal_main_name): New function.
        p-lang.c (GPC_MAIN_PROGRAM_NAME_1),
        (GPC_MAIN_PROGRAM_NAME_2): New char array constants
        corresponding to the two minimal symbols used
        by GPC compiler.
        (pascal_main_name): Try to find minimal symbol
        corresponding to the entry of GPC compiled programs.
        symtab.c: New include p-lang.h.
        (find_main_name): Try to find pascal specific main name
        by calling pascal_main_name.
        * Makefile.in (symtab.o): Add dependency on p-lang header.

$ cvs diff -up p-lang.h p-lang.c symtab.c Makefile.in
Index: p-lang.h
===================================================================
RCS file: /cvs/src/src/gdb/p-lang.h,v
retrieving revision 1.12
diff -u -p -r1.12 p-lang.h
--- p-lang.h    23 Aug 2007 18:08:36 -0000      1.12
+++ p-lang.h    26 Sep 2007 22:30:59 -0000
@@ -21,6 +21,9 @@

 struct value;

+/* Defined in p-lang.c */
+extern char *pascal_main_name (void);
+
 extern int pascal_parse (void);        /* Defined in p-exp.y */

 extern void pascal_error (char *);     /* Defined in p-exp.y */
Index: p-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/p-lang.c,v
retrieving revision 1.33
diff -u -p -r1.33 p-lang.c
--- p-lang.c    23 Sep 2007 16:25:05 -0000      1.33
+++ p-lang.c    26 Sep 2007 22:31:00 -0000
@@ -35,6 +35,43 @@
 extern void _initialize_pascal_language (void);


+/* The name of the symbol that GPC uses as the name of the main
+   subprogram (since version ...).  */
+static const char GPC_MAIN_PROGRAM_NAME_1[]
+  = "_p__M0_main_program";
+
+/* Older versions of GPC (version ... and older) were using
+   a different name for the main subprogram.  */
+static const char GPC_MAIN_PROGRAM_NAME_2[]
+  = "pascal_main_program";
+
+/* Function returning the special symbol name used
+   by GPC if it is found in minimal symbol list.  */
+
+char *
+pascal_main_name (void)
+{
+  struct minimal_symbol *msym;
+
+  msym = lookup_minimal_symbol (GPC_MAIN_PROGRAM_NAME_1, NULL, NULL);
+
+  if (msym != NULL)
+    {
+      return (char *)GPC_MAIN_PROGRAM_NAME_1;
+    }
+
+  msym = lookup_minimal_symbol (GPC_MAIN_PROGRAM_NAME_2, NULL, NULL);
+
+  if (msym != NULL)
+    {
+      return (char *)GPC_MAIN_PROGRAM_NAME_2;
+    }
+
+/*  The main procedure doesn't seem to be compiled with GPC.
+    Thus default name "main" should work.  */
+  return NULL;
+}
+
 /* Determines if type TYPE is a pascal string type.
    Returns 1 if the type is a known pascal type
    This function is used by p-valprint.c code to allow better string
display.
Index: symtab.c
===================================================================
RCS file: /cvs/src/src/gdb/symtab.c,v
retrieving revision 1.165
diff -u -p -r1.165 symtab.c
--- symtab.c    24 Sep 2007 07:40:32 -0000      1.165
+++ symtab.c    26 Sep 2007 22:31:02 -0000
@@ -40,6 +40,7 @@
 #include "filenames.h"         /* for FILENAME_CMP */
 #include "objc-lang.h"
 #include "ada-lang.h"
+#include "p-lang.h"

 #include "hashtab.h"

@@ -4151,6 +4152,13 @@ find_main_name (void)
       return;
     }

+  new_main_name = pascal_main_name ();
+  if (new_main_name != NULL)
+    {
+      set_main_name (new_main_name);
+      return;
+    }
+
   /* The languages above didn't identify the name of the main procedure.
      Fallback to "main".  */
   set_main_name ("main");
Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.938
diff -u -p -r1.938 Makefile.in
--- Makefile.in 17 Sep 2007 19:32:53 -0000      1.938
+++ Makefile.in 26 Sep 2007 22:31:04 -0000
@@ -2751,7 +2751,7 @@ symtab.o: symtab.c $(defs_h) $(symtab_h)
        $(filenames_h) $(objc_lang_h) $(ada_lang_h) $(hashtab_h) \
        $(gdb_obstack_h) $(block_h) $(dictionary_h) $(gdb_string_h) \
        $(gdb_stat_h) $(cp_abi_h) $(observer_h) $(gdb_assert_h) \
-       $(solist_h) $(ada_lang_h)
+       $(solist_h) $(p_lang_h)
 target.o: target.c $(defs_h) $(gdb_string_h) $(target_h) $(gdbcmd_h) \
        $(symtab_h) $(inferior_h) $(bfd_h) $(symfile_h) $(objfiles_h) \
        $(gdb_wait_h) $(dcache_h) $(regcache_h) $(gdb_assert_h) $(gdbcore_h)
\