Re: [PATCH] Pass manager: add support for termination of pass list

[Martin LiÅka <mliska at suse dot cz>]

On 11/03/2015 02:46 PM, Richard Biener wrote:
> On Fri, Oct 30, 2015 at 1:53 PM, Martin LiÅka <mliska@suse.cz> wrote:
>> On 10/30/2015 01:13 PM, Richard Biener wrote:
>>> So I suggest to do the push/pop of cfun there.
>>> do_per_function_toporder can be made static btw.
>>>
>>> Richard.
>>
>> Right, I've done that and it works (bootstrap has been currently running),
>> feasible for HSA branch too.
>>
>> tree-pass.h:
>>
>> /* Declare for plugins.  */
>> extern void do_per_function_toporder (void (*) (function *, void *), void *);
>>
>> Attaching the patch that I'm going to test.
> 
> Err.
> 
> +      cgraph_node::get (current_function_decl)->release_body ();
> +
> +      current_function_decl = NULL;
> +      set_cfun (NULL);
> 
> I'd have expected
> 
>       tree fn = cfun->decl;
>       pop_cfun ();
>       gcc_assert (!cfun);
>       cgraph_node::get (fn)->release_body ();
> 
> here.

Yeah, that works, but we have to add following hunk:

diff --git a/gcc/function.c b/gcc/function.c
index aaf49a4..4718fe1 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -4756,6 +4756,13 @@ push_cfun (struct function *new_cfun)
 void
 pop_cfun (void)
 {
+  if (cfun_stack.is_empty ())
+    {
+      set_cfun (NULL);
+      current_function_decl = NULL_TREE;
+      return;
+    }
+
   struct function *new_cfun = cfun_stack.pop ();
   /* When in_dummy_function, we do have a cfun but current_function_decl is
      NULL.  We also allow pushing NULL cfun and subsequently changing


If you are fine with that, looks we've fixed all issues related to the change, right?
Updated version of the is attached.

Martin

> 
>> Martin
>>

>From 0921507773eedadca1216a9edca954af240b7a49 Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Thu, 22 Oct 2015 12:46:16 +0200
Subject: [PATCH] Pass manager: add support for termination of pass list

gcc/ChangeLog:

2015-10-30  Martin Liska  <mliska@suse.cz>

	* function.c (pop_cfun): Set cfun and current_function_decl to
	NULL if the cfun_stack is empty.
	* passes.c (do_per_function_toporder): Push to cfun before
	calling the pass manager.
	(execute_one_pass): Handle TODO_discard_function.
	(execute_pass_list_1): Terminate if current function is null.
	(execute_pass_list): Do not push and pop function.
	* tree-pass.h: Define new TODO_discard_function.
---
 gcc/function.c  |  7 +++++++
 gcc/passes.c    | 32 ++++++++++++++++++++++++++++----
 gcc/tree-pass.h |  3 +++
 4 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/gcc/function.c b/gcc/function.c
index aaf49a4..4718fe1 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -4756,6 +4756,13 @@ push_cfun (struct function *new_cfun)
 void
 pop_cfun (void)
 {
+  if (cfun_stack.is_empty ())
+    {
+      set_cfun (NULL);
+      current_function_decl = NULL_TREE;
+      return;
+    }
+
   struct function *new_cfun = cfun_stack.pop ();
   /* When in_dummy_function, we do have a cfun but current_function_decl is
      NULL.  We also allow pushing NULL cfun and subsequently changing
diff --git a/gcc/passes.c b/gcc/passes.c
index d9af93a..d764a22 100644
--- a/gcc/passes.c
+++ b/gcc/passes.c
@@ -1706,7 +1706,12 @@ do_per_function_toporder (void (*callback) (function *, void *data), void *data)
 	  order[i] = NULL;
 	  node->process = 0;
 	  if (node->has_gimple_body_p ())
-	    callback (DECL_STRUCT_FUNCTION (node->decl), data);
+	    {
+	      struct function *fn = DECL_STRUCT_FUNCTION (node->decl);
+	      push_cfun (fn);
+	      callback (fn, data);
+	      pop_cfun ();
+	    }
 	}
       symtab->remove_cgraph_removal_hook (hook);
     }
@@ -2347,6 +2352,23 @@ execute_one_pass (opt_pass *pass)
 
   current_pass = NULL;
 
+  if (todo_after & TODO_discard_function)
+    {
+      gcc_assert (cfun);
+      /* As cgraph_node::release_body expects release dominators info,
+	 we have to release it.  */
+      if (dom_info_available_p (CDI_DOMINATORS))
+	free_dominance_info (CDI_DOMINATORS);
+
+      if (dom_info_available_p (CDI_POST_DOMINATORS))
+	free_dominance_info (CDI_POST_DOMINATORS);
+
+      tree fn = cfun->decl;
+      pop_cfun ();
+      gcc_assert (!cfun);
+      cgraph_node::get (fn)->release_body ();
+    }
+
   /* Signal this is a suitable GC collection point.  */
   if (!((todo_after | pass->todo_flags_finish) & TODO_do_not_ggc_collect))
     ggc_collect ();
@@ -2361,6 +2383,9 @@ execute_pass_list_1 (opt_pass *pass)
     {
       gcc_assert (pass->type == GIMPLE_PASS
 		  || pass->type == RTL_PASS);
+
+      if (cfun == NULL)
+	return;
       if (execute_one_pass (pass) && pass->sub)
         execute_pass_list_1 (pass->sub);
 
@@ -2372,14 +2397,13 @@ execute_pass_list_1 (opt_pass *pass)
 void
 execute_pass_list (function *fn, opt_pass *pass)
 {
-  push_cfun (fn);
+  gcc_assert (fn == cfun);
   execute_pass_list_1 (pass);
-  if (fn->cfg)
+  if (cfun && fn->cfg)
     {
       free_dominance_info (CDI_DOMINATORS);
       free_dominance_info (CDI_POST_DOMINATORS);
     }
-  pop_cfun ();
 }
 
 /* Write out all LTO data.  */
diff --git a/gcc/tree-pass.h b/gcc/tree-pass.h
index c03e3d8..713f068 100644
--- a/gcc/tree-pass.h
+++ b/gcc/tree-pass.h
@@ -300,6 +300,9 @@ protected:
 /* Rebuild the callgraph edges.  */
 #define TODO_rebuild_cgraph_edges       (1 << 22)
 
+/* Release function body and stop pass manager.  */
+#define TODO_discard_function		(1 << 23)
+
 /* Internally used in execute_function_todo().  */
 #define TODO_update_ssa_any		\
     (TODO_update_ssa			\
-- 
2.6.2