Re: [RFA] Handle GPC specific name for main function

[Joel Brobecker <brobecker@adacore.com>]

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Hi Eli,

> Yuck!  Can't we make pascal_main_name return `const char *'?  If not,
> why not?

That's a good idea. What do you think about this revised version
of Pierre's patch?

2007-10-07  Pierre Muller  <muller@ics.u-strasbg.fr>

        * p-lang.h (pascal_main_name): Add declaration.
        * p-lang.c (GPC_P_INITIALIZE, GPC_MAIN_PROGRAM_NAME_1)
        (GPC_MAIN_PROGRAM_NAME_2): New constants.
        (pascal_main_name): New function.
        * symtab.c: Include p-lang.h.
        (find_main_name): New function.
        * Makefile.in (symtab.o): Add dependency on p-lang.h.

Pierre,

This patch also implements the adjustments in the comments that
I suggested. The way you wrote these commments made me think that
you were implicitly thinking that your function is called only
when the program is written in Pascal (and only in Pascal). But
in fact, this is not the case, and the program could actually be
multi-language! I also noticed some formatting issues, which I
also fixed.

I also just now noticed that I had some comments on your ChangeLog
entry. Above is how I would write it: You were missing the '*' for
each new file; And I made the text more concise (no need to explain
what the function does for instance).

I should have noticed that the first time around, but being new at
reviewing patch, I'm still learning.

-- 
Joel

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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	7 Oct 2007 07:13:41 -0000
@@ -21,6 +21,9 @@
 
 struct value;
 
+/* Defined in p-lang.c */
+extern const char const *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	7 Oct 2007 07:13:41 -0000
@@ -35,6 +35,56 @@
 extern void _initialize_pascal_language (void);
 
 
+/* All GPC versions until now (2007-09-27) also define a symbol called
+   '_p_initialize'. Check for the presence of this symbol first.  */
+static const char GPC_P_INITIALIZE[] = "_p_initialize";
+
+/* The name of the symbol that GPC uses as the name of the main
+   procedure (since version 20050212).  */
+static const char GPC_MAIN_PROGRAM_NAME_1[] = "_p__M0_main_program";
+
+/* Older versions of GPC (versions older than 20050212) were using
+   a different name for the main procedure.  */
+static const char GPC_MAIN_PROGRAM_NAME_2[] = "pascal_main_program";
+
+/* Function returning the special symbol name used
+   by GPC for the main procedure in the main program
+   if it is found in minimal symbol list.
+   This function tries to find minimal symbols generated by GPC
+   so that it finds the even if the program was compiled
+   without debugging information.
+   According to information supplied by Waldeck Hebisch,
+   this should work for all versions posterior to June 2000. */
+
+const char const *
+pascal_main_name (void)
+{
+  struct minimal_symbol *msym;
+
+  msym = lookup_minimal_symbol (GPC_P_INITIALIZE, NULL, NULL);
+
+  /*  If '_p_initialize' was not found, the main program is likely not
+     written in Pascal.  */
+  if (msym == NULL)
+    return NULL;
+
+  msym = lookup_minimal_symbol (GPC_MAIN_PROGRAM_NAME_1, NULL, NULL);
+  if (msym != NULL)
+    {
+      return GPC_MAIN_PROGRAM_NAME_1;
+    }
+
+  msym = lookup_minimal_symbol (GPC_MAIN_PROGRAM_NAME_2, NULL, NULL);
+  if (msym != NULL)
+    {
+      return GPC_MAIN_PROGRAM_NAME_2;
+    }
+
+  /*  No known entry procedure found, the main program is probably
+      not in pascal.  */
+  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: Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/Makefile.in,v
retrieving revision 1.939
diff -u -p -r1.939 Makefile.in
--- Makefile.in	27 Sep 2007 18:48:32 -0000	1.939
+++ Makefile.in	7 Oct 2007 07:13:42 -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) \