[4/4] RFC: constify a quick function

[Tom Tromey <tromey at redhat dot com>]

This is just a small cleanup for a buglet I noticed while cleaning up
the patch series.

The quick function find_symbol_file returns a "char *", but I think it
really ought to return a "const char *".  This patch implements that
change.

Tom

b/gdb/ChangeLog:
2010-06-30  Tom Tromey  <tromey@redhat.com>

	* symfile.c (set_initial_language): Update.
	(deduce_language_from_filename): Argument type now const.
	* symtab.h (find_main_filename): Update.
	(deduce_language_from_filename): Update.
	* symtab.c (find_main_filename): Make result const.
	* dwarf2read.c (dw2_find_symbol_file): Change return type.
	* psymtab.c (find_symbol_file_from_partial): Change return type.
	* symfile.h (struct quick_symbol_functions) <find_symbol_file>:
	Make result const.

>From f594ce100ef85a24fe239262aae72e7834a75ce8 Mon Sep 17 00:00:00 2001
From: Tom Tromey <tromey@redhat.com>
Date: Wed, 30 Jun 2010 16:20:42 -0600
Subject: [PATCH 4/4] constify find_symbol_file

---
 gdb/ChangeLog    |   12 ++++++++++++
 gdb/dwarf2read.c |    5 ++---
 gdb/psymtab.c    |    2 +-
 gdb/symfile.c    |    4 ++--
 gdb/symfile.h    |    2 +-
 gdb/symtab.c     |    6 ++++--
 gdb/symtab.h     |    4 ++--
 7 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index c2626a7..6468284 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -2171,7 +2171,7 @@ dw2_expand_symtabs_with_filename (struct objfile *objfile,
     }
 }
 
-static char *
+static const char *
 dw2_find_symbol_file (struct objfile *objfile, const char *name)
 {
   struct dwarf2_per_cu_data *cu;
@@ -2197,8 +2197,7 @@ dw2_find_symbol_file (struct objfile *objfile, const char *name)
   if (!cu->v.quick->lines)
     return NULL;
 
-  return (char *) cu->v.quick->file_names[cu->v.quick->lines->num_file_names
-					  - 1];
+  return cu->v.quick->file_names[cu->v.quick->lines->num_file_names - 1];
 }
 
 static void
diff --git a/gdb/psymtab.c b/gdb/psymtab.c
index ca06130..c120894 100644
--- a/gdb/psymtab.c
+++ b/gdb/psymtab.c
@@ -949,7 +949,7 @@ psymtab_to_fullname (struct partial_symtab *ps)
   return NULL;
 }
 
-static char *
+static const char *
 find_symbol_file_from_partial (struct objfile *objfile, const char *name)
 {
   struct partial_symtab *pst;
diff --git a/gdb/symfile.c b/gdb/symfile.c
index af1b42c..babe9cf 100644
--- a/gdb/symfile.c
+++ b/gdb/symfile.c
@@ -1538,7 +1538,7 @@ symbol_file_command (char *args, int from_tty)
 void
 set_initial_language (void)
 {
-  char *filename;
+  const char *filename;
   enum language lang = language_unknown;
 
   filename = find_main_filename ();
@@ -2665,7 +2665,7 @@ init_filename_language_table (void)
 }
 
 enum language
-deduce_language_from_filename (char *filename)
+deduce_language_from_filename (const char *filename)
 {
   int i;
   char *cp;
diff --git a/gdb/symfile.h b/gdb/symfile.h
index d0fbb65..5815354 100644
--- a/gdb/symfile.h
+++ b/gdb/symfile.h
@@ -210,7 +210,7 @@ struct quick_symbol_functions
 
   /* Return the file name of the file holding the symbol in OBJFILE
      named NAME.  If no such symbol exists in OBJFILE, return NULL.  */
-  char *(*find_symbol_file) (struct objfile *objfile, const char *name);
+  const char *(*find_symbol_file) (struct objfile *objfile, const char *name);
 
   /* This method is specific to Ada.  It walks the partial symbol
      tables of OBJFILE looking for a name match.  WILD_MATCH and
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 4e48e48..07910db 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -1617,14 +1617,16 @@ basic_lookup_transparent_type (const char *name)
 /* FIXME:  What about languages without main() or specially linked
    executables that have no main() ? */
 
-char *
+const char *
 find_main_filename (void)
 {
   struct objfile *objfile;
-  char *result, *name = main_name ();
+  char *name = main_name ();
 
   ALL_OBJFILES (objfile)
   {
+    const char *result;
+
     if (!objfile->sf)
       continue;
     result = objfile->sf->qf->find_symbol_file (objfile, name);
diff --git a/gdb/symtab.h b/gdb/symtab.h
index bedc10a..f8c9496 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -1137,7 +1137,7 @@ extern char **make_source_files_completion_list (char *, char *);
 
 int matching_obj_sections (struct obj_section *, struct obj_section *);
 
-extern char *find_main_filename (void);
+extern const char *find_main_filename (void);
 
 extern struct symtab *find_line_symtab (struct symtab *, int, int *, int *);
 
@@ -1150,7 +1150,7 @@ extern void skip_prologue_sal (struct symtab_and_line *);
 
 extern void clear_symtab_users (void);
 
-extern enum language deduce_language_from_filename (char *);
+extern enum language deduce_language_from_filename (const char *);
 
 /* symtab.c */
 
-- 
1.6.2.5