move the "main" data into the per-BFD object

This adds the "main"-related data into the per-BFD.  This is needed
because once symbol sharing across objfiles is complete, computing the
main name as a side effect of symbol reading will no longer work --
the symbols simply won't be re-read.

After this change, set_main_name is only used by the main_name
machinery itself, so this patch makes it static.

2014-01-15  Tom Tromey  <tromey@redhat.com>

	* dbxread.c (process_one_symbol): Use set_objfile_main_name.
	* dwarf2read.c (read_partial_die): Use set_objfile_main_name.
	* objfiles.c (get_objfile_bfd_data): Initialize language_of_main.
	(set_objfile_main_name): New function.
	* objfiles.h (struct objfile_per_bfd_storage) <name_of_main,
	language_of_main>: New fields.
	(set_objfile_main_name): Declare.
	* symtab.c (find_main_name): Loop over objfiles to find the main
	name and language.
	(set_main_name): Now static.
	(get_main_info): Add comment.
	* symtab.h (set_main_name): Don't declare.

gdb/ChangeLog

@@ -1,3 +1,18 @@
+2014-01-15  Tom Tromey  <tromey@redhat.com>
+
+	* dbxread.c (process_one_symbol): Use set_objfile_main_name.
+	* dwarf2read.c (read_partial_die): Use set_objfile_main_name.
+	* objfiles.c (get_objfile_bfd_data): Initialize language_of_main.
+	(set_objfile_main_name): New function.
+	* objfiles.h (struct objfile_per_bfd_storage) <name_of_main,
+	language_of_main>: New fields.
+	(set_objfile_main_name): Declare.
+	* symtab.c (find_main_name): Loop over objfiles to find the main
+	name and language.
+	(set_main_name): Now static.
+	(get_main_info): Add comment.
+	* symtab.h (set_main_name): Don't declare.
+
 2014-01-15  Tom Tromey  <tromey@redhat.com>
 
 	* symtab.c (main_progspace_key): New global.

gdb/dbxread.c

@@ -3250,7 +3250,7 @@ process_one_symbol (int type, int desc, CORE_ADDR valu, char *name,
 	 N_MAIN within a given objfile, complain() and choose
 	 arbitrarily.  (kingdon) */
       if (name != NULL)
-	set_main_name (name, language_unknown);
+	set_objfile_main_name (objfile, name, language_unknown);
       break;
 
       /* The following symbol types can be ignored.  */

gdb/dwarf2read.c

@@ -15322,7 +15322,7 @@ read_partial_die (const struct die_reader_specs *reader,
 	     practice.  */
 	  if (DW_UNSND (&attr) == DW_CC_program
 	      && cu->language == language_fortran)
-	    set_main_name (part_die->name, language_fortran);
+	    set_objfile_main_name (objfile, part_die->name, language_fortran);
 	  break;
 	case DW_AT_inline:
 	  if (DW_UNSND (&attr) == DW_INL_inlined

gdb/objfiles.c

@@ -152,6 +152,7 @@ get_objfile_bfd_data (struct objfile *objfile, struct bfd *abfd)
       obstack_init (&storage->storage_obstack);
       storage->filename_cache = bcache_xmalloc (NULL, NULL);
       storage->macro_cache = bcache_xmalloc (NULL, NULL);
+      storage->language_of_main = language_unknown;
     }
 
   return storage;
@@ -186,6 +187,20 @@ set_objfile_per_bfd (struct objfile *objfile)
   objfile->per_bfd = get_objfile_bfd_data (objfile, objfile->obfd);
 }
 
+/* Set the objfile's per-BFD notion of the "main" name and
+   language.  */
+
+void
+set_objfile_main_name (struct objfile *objfile,
+		       const char *name, enum language lang)
+{
+  if (objfile->per_bfd->name_of_main == NULL
+      || strcmp (objfile->per_bfd->name_of_main, name) != 0)
+    objfile->per_bfd->name_of_main
+      = obstack_copy0 (&objfile->per_bfd->storage_obstack, name, strlen (name));
+  objfile->per_bfd->language_of_main = lang;
+}
+
 
 
 /* Called via bfd_map_over_sections to build up the section table that

gdb/objfiles.h

@@ -203,6 +203,13 @@ struct objfile_per_bfd_storage
      containing the entry point, and the scope of the user's main() func.  */
 
   struct entry_info ei;
+
+  /* The name and language of any "main" found in this objfile.  The
+     name can be NULL, which means that the information was not
+     recorded.  */
+
+  const char *name_of_main;
+  enum language language_of_main;
 };
 
 /* Master structure for keeping track of each file from which
@@ -691,4 +698,9 @@ void set_objfile_per_bfd (struct objfile *obj);
 
 const char *objfile_name (const struct objfile *objfile);
 
+/* Set the objfile's notion of the "main" name and language.  */
+
+extern void set_objfile_main_name (struct objfile *objfile,
+				   const char *name, enum language lang);
+
 #endif /* !defined (OBJFILES_H) */

gdb/symtab.c

@@ -5028,6 +5028,12 @@ get_main_info (void)
 
   if (info == NULL)
     {
+      /* It may seem strange to store the main name in the progspace
+	 and also in whatever objfile happens to see a main name in
+	 its debug info.  The reason for this is mainly historical:
+	 gdb returned "main" as the name even if no function named
+	 "main" was defined the program; and this approach lets us
+	 keep compatibility.  */
       info = XCNEW (struct main_info);
       info->language_of_main = language_unknown;
       set_program_space_data (current_program_space, main_progspace_key,
@@ -5050,7 +5056,7 @@ main_info_cleanup (struct program_space *pspace, void *data)
   xfree (info);
 }
 
-void
+static void
 set_main_name (const char *name, enum language lang)
 {
   struct main_info *info = get_main_info ();
@@ -5075,6 +5081,23 @@ static void
 find_main_name (void)
 {
   const char *new_main_name;
+  struct objfile *objfile;
+
+  /* First check the objfiles to see whether a debuginfo reader has
+     picked up the appropriate main name.  Historically the main name
+     was found in a more or less random way; this approach instead
+     relies on the order of objfile creation -- which still isn't
+     guaranteed to get the correct answer, but is just probably more
+     accurate.  */
+  ALL_OBJFILES (objfile)
+  {
+    if (objfile->per_bfd->name_of_main != NULL)
+      {
+	set_main_name (objfile->per_bfd->name_of_main,
+		       objfile->per_bfd->language_of_main);
+	return;
+      }
+  }
 
   /* Try to see if the main procedure is in Ada.  */
   /* FIXME: brobecker/2005-03-07: Another way of doing this would

gdb/symtab.h

@@ -1324,7 +1324,6 @@ extern struct cleanup *make_cleanup_free_search_symbols (struct symbol_search
    FIXME: cagney/2001-03-20: Can't make main_name() const since some
    of the calling code currently assumes that the string isn't
    const.  */
-extern void set_main_name (const char *name, enum language lang);
 extern /*const */ char *main_name (void);
 extern enum language main_language (void);