[RFA] remove free_contents

[RFA] remove free_contents

[Doug Evans]

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Hi.

symtab.h contains this:

struct general_symbol_info
{
 /* Name of the symbol.  This is a required field.  Storage for the
    name is allocated on the objfile_obstack for the associated
    objfile.  ...  */

 char *name;

[...]

#define DEPRECATED_SYMBOL_NAME(symbol)  (symbol)->ginfo.name

but symmisc.c does this:

static void
free_symtab_block (struct objfile *objfile, struct block *b)
{
 [...]
     xfree (DEPRECATED_SYMBOL_NAME (sym));
 [...]
}

Either the comment is incomplete (i.e. some names are not allocated
on an objfile_obstack), or the code is wrong (or in this case, outdated).

There's a FIXME that says free_symtab_block is likely never used
and that is the case.  free_contents is never used, which
is how free_symtab_block would get called.

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2008-04-03  Doug Evans  <dje@sebabeach.org>

	* symtab.h (enum free_code): Delete free_contents, unused.
	* symmisc.c (free_symtab_block): Delete.
	(free_symtab, case free_code): Delete.

Index: symmisc.c
===================================================================
RCS file: /cvs/src/src/gdb/symmisc.c,v
retrieving revision 1.48
diff -u -p -r1.48 symmisc.c
--- symmisc.c	17 Mar 2008 15:05:42 -0000	1.48
+++ symmisc.c	3 Apr 2008 17:39:09 -0000
@@ -70,8 +70,6 @@ static int block_depth (struct block *);
 static void print_partial_symbols (struct partial_symbol **, int,
 				   char *, struct ui_file *);
 
-static void free_symtab_block (struct objfile *, struct block *);
-
 void _initialize_symmisc (void);
 
 struct print_symbol_args
@@ -82,37 +80,12 @@ struct print_symbol_args
   };
 
 static int print_symbol (void *);
-
-static void free_symtab_block (struct objfile *, struct block *);
 \f
-
-/* Free a struct block <- B and all the symbols defined in that block.  */
-
-/* FIXME: carlton/2003-04-28: I don't believe this is currently ever
-   used.  */
-
-static void
-free_symtab_block (struct objfile *objfile, struct block *b)
-{
-  struct dict_iterator iter;
-  struct symbol *sym;
-
-  ALL_BLOCK_SYMBOLS (b, iter, sym)
-    {
-      xfree (DEPRECATED_SYMBOL_NAME (sym));
-      xfree (sym);
-    }
-
-  dict_free (BLOCK_DICT (b));
-  xfree (b);
-}
-
 /* Free all the storage associated with the struct symtab <- S.
-   Note that some symtabs have contents malloc'ed structure by structure,
-   while some have contents that all live inside one big block of memory,
-   and some share the contents of another symbol table and so you should
-   not free the contents on their behalf (except sometimes the linetable,
-   which maybe per symtab even when the rest is not).
+   Note that some symtabs have contents that all live inside one big block of
+   memory, and some share the contents of another symbol table and so you
+   should not free the contents on their behalf (except sometimes the
+   linetable, which maybe per symtab even when the rest is not).
    It is s->free_code that says which alternative to use.  */
 
 void
@@ -129,18 +102,6 @@ free_symtab (struct symtab *s)
          Therefore, do nothing.  */
       break;
 
-    case free_contents:
-      /* Here all the contents were malloc'ed structure by structure
-         and must be freed that way.  */
-      /* First free the blocks (and their symbols.  */
-      bv = BLOCKVECTOR (s);
-      n = BLOCKVECTOR_NBLOCKS (bv);
-      for (i = 0; i < n; i++)
-	free_symtab_block (s->objfile, BLOCKVECTOR_BLOCK (bv, i));
-      /* Free the blockvector itself.  */
-      xfree (bv);
-      /* Also free the linetable.  */
-
     case free_linetable:
       /* Everything will be freed either by our `free_func'
          or by some other symtab, except for our linetable.
Index: symtab.h
===================================================================
RCS file: /cvs/src/src/gdb/symtab.h,v
retrieving revision 1.112
diff -u -p -r1.112 symtab.h
--- symtab.h	5 Feb 2008 22:17:40 -0000	1.112
+++ symtab.h	3 Apr 2008 17:39:10 -0000
@@ -809,7 +809,6 @@ struct symtab
   char *dirname;
 
   /* This component says how to free the data we point to:
-     free_contents => do a tree walk and free each object.
      free_nothing => do nothing; some other symtab will free
      the data this one uses.
      free_linetable => free just the linetable.  FIXME: Is this redundant
@@ -817,7 +816,7 @@ struct symtab
 
   enum free_code
   {
-    free_nothing, free_contents, free_linetable
+    free_nothing, free_linetable
   }
   free_code;
 

Re: [RFA] remove free_contents

[Daniel Jacobowitz]

On Thu, Apr 03, 2008 at 10:54:48AM -0700, Doug Evans wrote:
> Either the comment is incomplete (i.e. some names are not allocated
> on an objfile_obstack), or the code is wrong (or in this case, outdated).

Both possible, I think, as long as the name has lifetime at least as
long as the objfile_obstack.  It could come from mmaped dwarf
sections, for instance (if we get around to making that work... I see
that conversation on a patch to do this trailed off).

> 2008-04-03  Doug Evans  <dje@sebabeach.org>
> 
> 	* symtab.h (enum free_code): Delete free_contents, unused.
> 	* symmisc.c (free_symtab_block): Delete.
> 	(free_symtab, case free_code): Delete.

OK, thanks.

-- 
Daniel Jacobowitz
CodeSourcery