From patchwork Thu Jun 10 23:23:07 2010
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Subject: Move df_live and df_md bitmaps to own obstacks
Date: Thu, 10 Jun 2010 13:23:07 -0000
From: "H.J. Lu" <hjl.tools@gmail.com>
X-Patchwork-Id: 55277
Message-Id: <AANLkTim6Nr1Bl53YjTxip7UgURrv5Vep7qsqxNOuhmIz@mail.gmail.com>
To: Jan Hubicka <hubicka@ucw.cz>
Cc: gcc-patches@gcc.gnu.org, bonzini@gnu.org

On Thu, Jun 10, 2010 at 3:41 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Jun 10, 2010 at 4:35 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
>> Hi,
>> this patch moves df_live and df_md bitmaps to own obstacks.  I believe those
>> are all important df problems that depends on bitmap performance?
>>
>> Bootstrapped/regtested x86_64-linux (with df checking)
>> OK?
>>
>> Honza
>>
>>        * df-problems.c (df_live_problem_data): Add live_bitmaps.
>>        (df_live_alloc): Initialize problem data and live_osbtacks.
>>        (df_live_finalize): Remove obstack, problem data; do not
>>        clear all bitmaps.
>>        (df_live_top_dump, df_live_bottom_dump): Do not dump old
>>        data when not allocated.
>>        (df_live_verify_solution_start): Do not allocate problem data.
>>        (df_live_verify_solution_end): Check if out is allocated.
>>        (struct df_md_problem_data): New structure.
>>        (df_md_alloc): Allocate problem data.
>>        (df_md_free): Free problem data; do not clear bitmaps.
>>
>
> This caused:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44498
>

We have


   if (!df_live_scratch)
-    df_live_scratch = BITMAP_ALLOC (NULL);
+    df_live_scratch = BITMAP_ALLOC (&problem_data->live_bitmaps);
...
+      bitmap_obstack_release (&problem_data->live_bitmaps);

       if (df_live_scratch)
        BITMAP_FREE (df_live_scratch);

We are calling bitmap_obstack_free after bitmap_obstack_release is called. Does
this patch make any senses?


Index: df-problems.c
===================================================================
--- df-problems.c	(revision 160549)
+++ df-problems.c	(working copy)
@@ -1645,8 +1645,8 @@ df_live_free (void)
       free (df_live->block_info);
       bitmap_obstack_release (&problem_data->live_bitmaps);

-      if (df_live_scratch)
-	BITMAP_FREE (df_live_scratch);
+      /* df_live_scratch is allocated from problem_data->live_bitmaps.  */
+      df_live_scratch = (bitmap) NULL;
     }
   BITMAP_FREE (df_live->out_of_date_transfer_functions);
   free (df_live);