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

[Jakub Jelinek]

On Mon, Jan 06, 2014 at 10:27:06AM +0000, Richard Sandiford wrote:
> Of course, IMO, the cleanest fix would be to use switchable targets
> for i386...

The following patch does that, bootstrapped/regtested on x86_64-linux and
i686-linux.  The only problem with the patch is PCH,
+FAIL: 17_intro/headers/c++200x/stdc++.cc (test for excess errors)
+FAIL: 17_intro/headers/c++200x/stdc++_multiple_inclusion.cc (test for excess errors)
(both 32-bit and 64-bit regtests), where it ICEs.  I guess the problem is
that the target globals are allocated partly in GC, partly in heap and
even if they were allocated completely in GC and GTY(()) marked fully all
the individual pointed structures, we IMNSHO still don't want it to be
saved during PCH and restored later, what we have is basically just a cache
of the target globals.

Dunno what is the best way to handle that though.
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?

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.
	* target-globals.h (struct target_globals): Define even if
	!SWITCHABLE_TARGET.
	* 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.

--- 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 12:55:39.137295100 +0100
@@ -2695,6 +2695,9 @@ 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);
 
--- 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/config/i386/i386.h.jj	2014-01-06 22:37:19.000000000 +0100
+++ gcc/config/i386/i386.h	2014-01-07 12:13:06.480486755 +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 16:52:32.597904760 +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