[PATCH] Change i?86/x86_64 into SWITCHABLE_TARGET (PR58115, take 2)

Jakub Jelinek jakub@redhat.com
Wed Jan 8 12:45:00 GMT 2014


On Wed, Jan 08, 2014 at 12:32:59PM +0100, Richard Biener wrote:
> > Either before writing PCH c-common.c could call some tree.c routine that
> > would traverse the cl_option_hash_table hash table and for every
> > TARGET_OPTION_NODE in the hash table clear TREE_TARGET_GLOBALS.
> > Or perhaps some gengtype extension to run some routine before PCH saving
> > on the tree_target_option structs and clear the globals field in there.
> > Or use GTY((user)) on tree_target_option, but then dunno how we'd handle the
> > marking of the embedded opts field (and common).
> > Any ideas?
> 
> Well, a GTY((skip_pch)) would probably work.  Or move the thing
> out-of GC land (thus make cl_option_hash_table persistant) and
> simply GTY((skip)) the pointer completely.  Not sure if we ever
> collect from it.

Even if the pointer was out of GCC land and GTY((skip)), we'd need to clear
it somewhere during PCH saving, as the containing structure is GC allocated.

I've already implemented in the mean time the variant with the
htab_traverse, all still reachable TARGET_OPTION_NODE trees should be in that
hash table.

Bootstrapped/regtested on x86_64-linux and i686-linux (in both cases with
--enable-checking=yes,rtl and --enable-checking=release, for the
i686-linux/release checking I had to fix an unrelated compare debug issue
I'll post when I manage to reduce testcase).

I'd like to get rid of all the XCNEW calls in target-globals.c as a
follow-up.

As for performance, for --enable-checking=release from very rough check
on make -j48 bootstrap and make -j48 check times the patch is compile time
neutral, on e.g. declare-simd-1.C testcase g++ is twice as fast with the
patch though (~ 0.8 sec without the patch, ~ 0.3 sec with the patch, both
for x86_64 and i686).

Ok for trunk?

2014-01-07  Jakub Jelinek  <jakub@redhat.com>

	PR target/58115
	* tree-core.h (struct target_globals): New forward declaration.
	(struct tree_target_option): Add globals field.
	* tree.h (TREE_TARGET_GLOBALS): Define.
	(prepare_target_option_nodes_for_pch): New prototype.
	* target-globals.h (struct target_globals): Define even if
	!SWITCHABLE_TARGET.
	* tree.c (prepare_target_option_node_for_pch,
	prepare_target_option_nodes_for_pch): New functions.
	* config/i386/i386.h (SWITCHABLE_TARGET): Define.
	* config/i386/i386.c: Include target-globals.h.
	(ix86_set_current_function): Instead of doing target_reinit
	unconditionally, use save_target_globals_default_opts and
	restore_target_globals.
c-family/
	* c-pch.c (c_common_write_pch): Call
	prepare_target_option_nodes_for_pch.

--- gcc/tree-core.h.jj	2014-01-07 08:47:24.000000000 +0100
+++ gcc/tree-core.h	2014-01-07 16:44:35.591358235 +0100
@@ -1557,11 +1557,18 @@ struct GTY(()) tree_optimization_option
   struct target_optabs *GTY ((skip)) base_optabs;
 };
 
+/* Forward declaration, defined in target-globals.h.  */
+
+struct GTY(()) target_globals;
+
 /* Target options used by a function.  */
 
 struct GTY(()) tree_target_option {
   struct tree_common common;
 
+  /* Target globals for the corresponding target option.  */
+  struct target_globals *globals;
+
   /* The optimization options used by the user.  */
   struct cl_target_option opts;
 };
--- gcc/tree.h.jj	2014-01-03 11:40:33.000000000 +0100
+++ gcc/tree.h	2014-01-07 21:28:15.038061120 +0100
@@ -2695,9 +2695,14 @@ extern tree build_optimization_node (str
 #define TREE_TARGET_OPTION(NODE) \
   (&TARGET_OPTION_NODE_CHECK (NODE)->target_option.opts)
 
+#define TREE_TARGET_GLOBALS(NODE) \
+  (TARGET_OPTION_NODE_CHECK (NODE)->target_option.globals)
+
 /* Return a tree node that encapsulates the target options in OPTS.  */
 extern tree build_target_option_node (struct gcc_options *opts);
 
+extern void prepare_target_option_nodes_for_pch (void);
+
 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
 
 inline tree
--- gcc/target-globals.h.jj	2014-01-03 11:40:46.000000000 +0100
+++ gcc/target-globals.h	2014-01-07 17:08:51.113880947 +0100
@@ -37,6 +37,7 @@ extern struct target_builtins *this_targ
 extern struct target_gcse *this_target_gcse;
 extern struct target_bb_reorder *this_target_bb_reorder;
 extern struct target_lower_subreg *this_target_lower_subreg;
+#endif
 
 struct GTY(()) target_globals {
   struct target_flag_state *GTY((skip)) flag_state;
@@ -57,6 +58,7 @@ struct GTY(()) target_globals {
   struct target_lower_subreg *GTY((skip)) lower_subreg;
 };
 
+#if SWITCHABLE_TARGET
 extern struct target_globals default_target_globals;
 
 extern struct target_globals *save_target_globals (void);
--- gcc/tree.c.jj	2014-01-03 11:40:33.000000000 +0100
+++ gcc/tree.c	2014-01-07 21:27:35.590268195 +0100
@@ -11527,6 +11527,28 @@ build_target_option_node (struct gcc_opt
   return t;
 }
 
+/* Reset TREE_TARGET_GLOBALS cache for TARGET_OPTION_NODE.
+   Called through htab_traverse.  */
+
+static int
+prepare_target_option_node_for_pch (void **slot, void *)
+{
+  tree node = (tree) *slot;
+  if (TREE_CODE (node) == TARGET_OPTION_NODE)
+    TREE_TARGET_GLOBALS (node) = NULL;
+  return 1;
+}
+
+/* Clear TREE_TARGET_GLOBALS of all TARGET_OPTION_NODE trees,
+   so that they aren't saved during PCH writing.  */
+
+void
+prepare_target_option_nodes_for_pch (void)
+{
+  htab_traverse (cl_option_hash_table, prepare_target_option_node_for_pch,
+		 NULL);
+}
+
 /* Determine the "ultimate origin" of a block.  The block may be an inlined
    instance of an inlined instance of a block which is local to an inline
    function, so we have to trace all of the way back through the origin chain
--- gcc/c-family/c-pch.c.jj	2014-01-03 11:40:29.000000000 +0100
+++ gcc/c-family/c-pch.c	2014-01-07 21:29:42.985600418 +0100
@@ -180,6 +180,8 @@ c_common_write_pch (void)
 
   (*debug_hooks->handle_pch) (1);
 
+  prepare_target_option_nodes_for_pch ();
+
   cpp_write_pch_deps (parse_in, pch_outfile);
 
   gt_pch_save (pch_outfile);
--- gcc/config/i386/i386.h.jj	2014-01-06 22:37:19.000000000 +0100
+++ gcc/config/i386/i386.h	2014-01-07 17:21:09.049106675 +0100
@@ -2510,6 +2510,9 @@ extern void debug_dispatch_window (int);
 #define IX86_HLE_ACQUIRE (1 << 16)
 #define IX86_HLE_RELEASE (1 << 17)
 
+/* For switching between functions with different target attributes.  */
+#define SWITCHABLE_TARGET 1
+
 /*
 Local variables:
 version-control: t
--- gcc/config/i386/i386.c.jj	2014-01-06 22:37:19.000000000 +0100
+++ gcc/config/i386/i386.c	2014-01-07 17:21:09.049106675 +0100
@@ -80,6 +80,7 @@ along with GCC; see the file COPYING3.
 #include "tree-pass.h"
 #include "context.h"
 #include "pass_manager.h"
+#include "target-globals.h"
 
 static rtx legitimize_dllimport_symbol (rtx, bool);
 static rtx legitimize_pe_coff_extern_decl (rtx, bool);
@@ -4868,16 +4869,25 @@ ix86_set_current_function (tree fndecl)
 	{
 	  cl_target_option_restore (&global_options,
 				    TREE_TARGET_OPTION (new_tree));
-	  target_reinit ();
+	  if (TREE_TARGET_GLOBALS (new_tree))
+	    restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+	  else
+	    TREE_TARGET_GLOBALS (new_tree)
+	      = save_target_globals_default_opts ();
 	}
 
       else if (old_tree)
 	{
-	  struct cl_target_option *def
-	    = TREE_TARGET_OPTION (target_option_current_node);
-
-	  cl_target_option_restore (&global_options, def);
-	  target_reinit ();
+	  new_tree = target_option_current_node;
+	  cl_target_option_restore (&global_options,
+				    TREE_TARGET_OPTION (new_tree));
+	  if (TREE_TARGET_GLOBALS (new_tree))
+	    restore_target_globals (TREE_TARGET_GLOBALS (new_tree));
+	  else if (new_tree == target_option_default_node)
+	    restore_target_globals (&default_target_globals);
+	  else
+	    TREE_TARGET_GLOBALS (new_tree)
+	      = save_target_globals_default_opts ();
 	}
     }
 }


	Jakub



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