From: Jan Hubicka <hubicka@ucw.cz>
Date: Wed, 10 Dec 2014 21:17:28 +0000 (+0100)
Subject: invoke.texi: (-devirtualize-at-ltrans): Document.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=1e29e4d36f701712b541e989ff091d7a6ce1afcd;p=gcc.git

invoke.texi: (-devirtualize-at-ltrans): Document.

	* doc/invoke.texi: (-devirtualize-at-ltrans): Document.
	* lto-cgraph.c (lto_output_varpool_node): Mark initializer as removed
	when it is not streamed to the given ltrans.
	(compute_ltrans_boundary): Make code adding all polymorphic
	call targets conditional with !flag_wpa || flag_ltrans_devirtualize.
	* common.opt (fdevirtualize-at-ltrans): New flag.

From-SVN: r218609
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6befea5041c..a9378a560c4 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2014-12-10  Jan Hubicka  <hubicka@ucw.cz>
+
+	* doc/invoke.texi: (-devirtualize-at-ltrans): Document.
+	* lto-cgraph.c (lto_output_varpool_node): Mark initializer as removed
+	when it is not streamed to the given ltrans.
+	(compute_ltrans_boundary): Make code adding all polymorphic
+	call targets conditional with !flag_wpa || flag_ltrans_devirtualize.
+	* common.opt (fdevirtualize-at-ltrans): New flag.
+
 2014-12-10  Ilya Verbin  <ilya.verbin@intel.com>
 
 	* varpool.c (varpool_node::get_create): Force output of vars with
diff --git a/gcc/common.opt b/gcc/common.opt
index 78b796b8557..3b8b14d4626 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1062,6 +1062,10 @@ fdelete-null-pointer-checks
 Common Report Var(flag_delete_null_pointer_checks) Init(1) Optimization
 Delete useless null pointer checks
 
+fdevirtualize-at-ltrans
+Common Report Var(flag_ltrans_devirtualize)
+Perofrm extra streaming to support more agressive devirtualization at LTO ltrans stage.
+
 fdevirtualize-speculatively
 Common Report Var(flag_devirtualize_speculatively) Optimization
 Perform speculative devirtualization
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index d2f3c79536a..1579702e20a 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -375,7 +375,8 @@ Objective-C and Objective-C++ Dialects}.
 -fcse-follow-jumps -fcse-skip-blocks -fcx-fortran-rules @gol
 -fcx-limited-range @gol
 -fdata-sections -fdce -fdelayed-branch @gol
--fdelete-null-pointer-checks -fdevirtualize -fdevirtualize-speculatively -fdse @gol
+-fdelete-null-pointer-checks -fdevirtualize -fdevirtualize-speculatively @gol
+-devirtualize-at-ltrans -fdse @gol
 -fearly-inlining -fipa-sra -fexpensive-optimizations -ffat-lto-objects @gol
 -ffast-math -ffinite-math-only -ffloat-store -fexcess-precision=@var{style} @gol
 -fforward-propagate -ffp-contract=@var{style} -ffunction-sections @gol
@@ -7730,6 +7731,13 @@ the call into an conditional deciding on direct and indirect call.  The
 speculative calls enable more optimizations, such as inlining.  When they seem
 useless after further optimization, they are converted back into original form.
 
+@item -fdevirtualize-at-ltrans
+@opindex fdevirtualize-at-ltrans
+Perform extra streaming needed for agressive devirtualization during LTO local
+transformation stage. This option enables more devirtualization but
+significantly increases the size of streamed data. For this reason it is
+disabled by default.
+
 @item -fexpensive-optimizations
 @opindex fexpensive-optimizations
 Perform a number of minor optimizations that are relatively expensive.
diff --git a/gcc/lto-cgraph.c b/gcc/lto-cgraph.c
index b310b446808..cf92892ba00 100644
--- a/gcc/lto-cgraph.c
+++ b/gcc/lto-cgraph.c
@@ -615,7 +615,8 @@ lto_output_varpool_node (struct lto_simple_output_block *ob, varpool_node *node,
   bp_pack_value (&bp, node->force_output, 1);
   bp_pack_value (&bp, node->forced_by_abi, 1);
   bp_pack_value (&bp, node->unique_name, 1);
-  bp_pack_value (&bp, node->body_removed, 1);
+  bp_pack_value (&bp, node->body_removed
+		 || !lto_symtab_encoder_encode_initializer_p (encoder, node), 1);
   bp_pack_value (&bp, node->implicit_section, 1);
   bp_pack_value (&bp, node->writeonly, 1);
   bp_pack_value (&bp, node->definition, 1);
@@ -910,8 +911,11 @@ compute_ltrans_boundary (lto_symtab_encoder_t in_encoder)
 	{
 	  if (!lto_symtab_encoder_encode_initializer_p (encoder,
 							vnode)
-	      && (vnode->ctor_useable_for_folding_p ()
-		  || POINTER_BOUNDS_P (vnode->decl)))
+	      && (((vnode->ctor_useable_for_folding_p ()
+		   && (!DECL_VIRTUAL_P (vnode->decl)
+		       || !flag_wpa
+		       || flag_ltrans_devirtualize))
+		  || POINTER_BOUNDS_P (vnode->decl))))
 	    {
 	      lto_set_symtab_encoder_encode_initializer (encoder, vnode);
 	      create_references (encoder, vnode);
@@ -936,7 +940,7 @@ compute_ltrans_boundary (lto_symtab_encoder_t in_encoder)
 	    }
 	}
       /* Add all possible targets for late devirtualization.  */
-      if (flag_devirtualize)
+      if (flag_ltrans_devirtualize || !flag_wpa)
 	for (edge = node->indirect_calls; edge; edge = edge->next_callee)
 	  if (edge->indirect_info->polymorphic)
 	    {