Re: [PATCH] Allocate all target globals using GC for SWITCHABLE_TARGETs

[Jakub Jelinek <jakub at redhat dot com>]

On Thu, Jan 09, 2014 at 08:42:03AM -0800, Richard Henderson wrote:
> On 01/09/2014 08:35 AM, Jakub Jelinek wrote:
> > That would be fine for 1), but would mean 2).  It is also fine to GC
> > allocate each structure individually, but some (like bb_reorder) are say
> > just 4 bytes long, so it might be overkill.
> 
> 
> Hmm..  Perhaps define the whole structure as you do, but somewhere global
> enough that ggc-page.c can see it, and add to the extra_order_size_table?
> I don't know how much memory wastage there would be there, but I can't imagine
> it's as much as 0.5MB.

Here is the solution I was talking about earlier, allocate smaller structs
through GC together and larger separately.  Bootstrapped/regtested on
x86_64-linux and i686-linux.

2014-01-09  Jakub Jelinek  <jakub@redhat.com>

	* target-globals.c (save_target_globals): Allocate < 4KB structs using
	GC in payload of target_globals struct instead of allocating them on
	the heap and the larger structs separately using GC.
	* target-globals.h (struct target_globals): Make regs, hard_regs,
	reload, expmed, ira, ira_int and lra_fields GTY((atomic)) instead
	of GTY((skip)) and change type to void *.
	(reset_target_globals): Cast loads from those fields to corresponding
	types.

--- gcc/target-globals.h.jj	2014-01-09 19:24:20.000000000 +0100
+++ gcc/target-globals.h	2014-01-09 19:39:43.879348712 +0100
@@ -41,17 +41,17 @@ extern struct target_lower_subreg *this_
 
 struct GTY(()) target_globals {
   struct target_flag_state *GTY((skip)) flag_state;
-  struct target_regs *GTY((skip)) regs;
+  void *GTY((atomic)) regs;
   struct target_rtl *rtl;
-  struct target_hard_regs *GTY((skip)) hard_regs;
-  struct target_reload *GTY((skip)) reload;
-  struct target_expmed *GTY((skip)) expmed;
+  void *GTY((atomic)) hard_regs;
+  void *GTY((atomic)) reload;
+  void *GTY((atomic)) expmed;
   struct target_optabs *GTY((skip)) optabs;
   struct target_libfuncs *libfuncs;
   struct target_cfgloop *GTY((skip)) cfgloop;
-  struct target_ira *GTY((skip)) ira;
-  struct target_ira_int *GTY((skip)) ira_int;
-  struct target_lra_int *GTY((skip)) lra_int;
+  void *GTY((atomic)) ira;
+  void *GTY((atomic)) ira_int;
+  void *GTY((atomic)) lra_int;
   struct target_builtins *GTY((skip)) builtins;
   struct target_gcse *GTY((skip)) gcse;
   struct target_bb_reorder *GTY((skip)) bb_reorder;
@@ -68,17 +68,17 @@ static inline void
 restore_target_globals (struct target_globals *g)
 {
   this_target_flag_state = g->flag_state;
-  this_target_regs = g->regs;
+  this_target_regs = (struct target_regs *) g->regs;
   this_target_rtl = g->rtl;
-  this_target_hard_regs = g->hard_regs;
-  this_target_reload = g->reload;
-  this_target_expmed = g->expmed;
+  this_target_hard_regs = (struct target_hard_regs *) g->hard_regs;
+  this_target_reload = (struct target_reload *) g->reload;
+  this_target_expmed = (struct target_expmed *) g->expmed;
   this_target_optabs = g->optabs;
   this_target_libfuncs = g->libfuncs;
   this_target_cfgloop = g->cfgloop;
-  this_target_ira = g->ira;
-  this_target_ira_int = g->ira_int;
-  this_target_lra_int = g->lra_int;
+  this_target_ira = (struct target_ira *) g->ira;
+  this_target_ira_int = (struct target_ira_int *) g->ira_int;
+  this_target_lra_int = (struct target_lra_int *) g->lra_int;
   this_target_builtins = g->builtins;
   this_target_gcse = g->gcse;
   this_target_bb_reorder = g->bb_reorder;
--- gcc/target-globals.c.jj	2014-01-08 17:44:57.551583153 +0100
+++ gcc/target-globals.c	2014-01-09 19:38:21.013760564 +0100
@@ -68,24 +68,44 @@ struct target_globals *
 save_target_globals (void)
 {
   struct target_globals *g;
-
-  g = ggc_alloc_target_globals ();
-  g->flag_state = XCNEW (struct target_flag_state);
-  g->regs = XCNEW (struct target_regs);
+  struct target_globals_extra {
+    struct target_globals g;
+    struct target_flag_state flag_state;
+    struct target_optabs optabs;
+    struct target_cfgloop cfgloop;
+    struct target_builtins builtins;
+    struct target_gcse gcse;
+    struct target_bb_reorder bb_reorder;
+    struct target_lower_subreg lower_subreg;
+  } *p;
+  p = (struct target_globals_extra *)
+      ggc_internal_cleared_alloc_stat (sizeof (struct target_globals_extra)
+				       PASS_MEM_STAT);
+  g = (struct target_globals *) p;
+  g->flag_state = &p->flag_state;
+  g->regs = ggc_internal_cleared_alloc_stat (sizeof (struct target_regs)
+					     PASS_MEM_STAT);
   g->rtl = ggc_alloc_cleared_target_rtl ();
-  g->hard_regs = XCNEW (struct target_hard_regs);
-  g->reload = XCNEW (struct target_reload);
-  g->expmed = XCNEW (struct target_expmed);
-  g->optabs = XCNEW (struct target_optabs);
+  g->hard_regs
+    = ggc_internal_cleared_alloc_stat (sizeof (struct target_hard_regs)
+				       PASS_MEM_STAT);
+  g->reload = ggc_internal_cleared_alloc_stat (sizeof (struct target_reload)
+					       PASS_MEM_STAT);
+  g->expmed =  ggc_internal_cleared_alloc_stat (sizeof (struct target_expmed)
+						PASS_MEM_STAT);
+  g->optabs = &p->optabs;
   g->libfuncs = ggc_alloc_cleared_target_libfuncs ();
-  g->cfgloop = XCNEW (struct target_cfgloop);
-  g->ira = XCNEW (struct target_ira);
-  g->ira_int = XCNEW (struct target_ira_int);
-  g->lra_int = XCNEW (struct target_lra_int);
-  g->builtins = XCNEW (struct target_builtins);
-  g->gcse = XCNEW (struct target_gcse);
-  g->bb_reorder = XCNEW (struct target_bb_reorder);
-  g->lower_subreg = XCNEW (struct target_lower_subreg);
+  g->cfgloop = &p->cfgloop;
+  g->ira = ggc_internal_cleared_alloc_stat (sizeof (struct target_ira)
+					    PASS_MEM_STAT);
+  g->ira_int = ggc_internal_cleared_alloc_stat (sizeof (struct target_ira_int)
+						PASS_MEM_STAT);
+  g->lra_int = ggc_internal_cleared_alloc_stat (sizeof (struct target_lra_int)
+						PASS_MEM_STAT);
+  g->builtins = &p->builtins;
+  g->gcse = &p->gcse;
+  g->bb_reorder = &p->bb_reorder;
+  g->lower_subreg = &p->lower_subreg;
   restore_target_globals (g);
   init_reg_sets ();
   target_reinit ();


	Jakub