Backport r257490

2018-03-06  Martin Liska  <mliska@suse.cz>

	Backport from mainline
	2018-02-08  Jan Hubicka  <hubicka@ucw.cz>

	PR ipa/81360
	* cgraph.h (symtab_node::output_to_lto_symbol_table_p): Declare
	* symtab.c: Include builtins.h
	(symtab_node::output_to_lto_symbol_table_p): Move here
	from lto-streamer-out.c:output_symbol_p.
	* lto-streamer-out.c (write_symbol): Turn early exit to assert.
	(output_symbol_p): Move all logic to symtab.c
	(produce_symtab): Update.
2018-03-06  Martin Liska  <mliska@suse.cz>

	Backport from mainline
	2018-02-08  Jan Hubicka  <hubicka@ucw.cz>

	PR ipa/81360
	* lto.c (unify_scc): Register prevailing trees, not trees to be freed.
	(read_cgraph_and_symbols): Use
	symtab_node::output_to_lto_symbol_table_p.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-7-branch@258289 138bc75d-0d04-0410-961f-82ee72b054a4

7 files changed, 105 insertions, 56 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7a29fd8a94c..e780652c3ba 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,17 @@
+2018-03-06  Martin Liska  <mliska@suse.cz>
+
+	Backport from mainline
+	2018-02-08  Jan Hubicka  <hubicka@ucw.cz>
+
+	PR ipa/81360
+	* cgraph.h (symtab_node::output_to_lto_symbol_table_p): Declare
+	* symtab.c: Include builtins.h
+	(symtab_node::output_to_lto_symbol_table_p): Move here
+	from lto-streamer-out.c:output_symbol_p.
+	* lto-streamer-out.c (write_symbol): Turn early exit to assert.
+	(output_symbol_p): Move all logic to symtab.c
+	(produce_symtab): Update.
+
 2018-03-06  Peter Bergner  <bergner@vnet.ibm.com>
 
 	Backport from mainline
diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index be4eaee71e2..ee053885442 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -321,6 +321,9 @@ public:
      or abstract function kept for debug info purposes only.  */
   bool real_symbol_p (void);
 
+  /* Return true when the symbol needs to be output to the LTO symbol table.  */
+  bool output_to_lto_symbol_table_p (void);
+
   /* Determine if symbol declaration is needed.  That is, visible to something
      either outside this translation unit, something magic in the system
      configury. This function is used just during symbol creation.  */
diff --git a/gcc/lto-streamer-out.c b/gcc/lto-streamer-out.c
index b96b9df63b7..89313727068 100644
--- a/gcc/lto-streamer-out.c
+++ b/gcc/lto-streamer-out.c
@@ -2524,13 +2524,10 @@ write_symbol (struct streamer_tree_cache_d *cache,
   const char *comdat;
   unsigned char c;
 
-  /* None of the following kinds of symbols are needed in the
-     symbol table.  */
-  if (!TREE_PUBLIC (t)
-      || is_builtin_fn (t)
-      || DECL_ABSTRACT_P (t)
-      || (VAR_P (t) && DECL_HARD_REGISTER (t)))
-    return;
+  gcc_checking_assert (TREE_PUBLIC (t)
+		       && !is_builtin_fn (t)
+		       && !DECL_ABSTRACT_P (t)
+		       && (!VAR_P (t) || !DECL_HARD_REGISTER (t)));
 
   gcc_assert (VAR_OR_FUNCTION_DECL_P (t));
 
@@ -2618,45 +2615,6 @@ write_symbol (struct streamer_tree_cache_d *cache,
   lto_write_data (&slot_num, 4);
 }
 
-/* Return true if NODE should appear in the plugin symbol table.  */
-
-bool
-output_symbol_p (symtab_node *node)
-{
-  struct cgraph_node *cnode;
-  if (!node->real_symbol_p ())
-    return false;
-  /* We keep external functions in symtab for sake of inlining
-     and devirtualization.  We do not want to see them in symbol table as
-     references unless they are really used.  */
-  cnode = dyn_cast <cgraph_node *> (node);
-  if (cnode && (!node->definition || DECL_EXTERNAL (cnode->decl))
-      && cnode->callers)
-    return true;
-
- /* Ignore all references from external vars initializers - they are not really
-    part of the compilation unit until they are used by folding.  Some symbols,
-    like references to external construction vtables can not be referred to at all.
-    We decide this at can_refer_decl_in_current_unit_p.  */
- if (!node->definition || DECL_EXTERNAL (node->decl))
-    {
-      int i;
-      struct ipa_ref *ref;
-      for (i = 0; node->iterate_referring (i, ref); i++)
-	{
-	  if (ref->use == IPA_REF_ALIAS)
-	    continue;
-          if (is_a <cgraph_node *> (ref->referring))
-	    return true;
-	  if (!DECL_EXTERNAL (ref->referring->decl))
-	    return true;
-	}
-      return false;
-    }
-  return true;
-}
-
-
 /* Write an IL symbol table to OB.
    SET and VSET are cgraph/varpool node sets we are outputting.  */
 
@@ -2681,7 +2639,7 @@ produce_symtab (struct output_block *ob)
     {
       symtab_node *node = lsei_node (lsei);
 
-      if (!output_symbol_p (node) || DECL_EXTERNAL (node->decl))
+      if (DECL_EXTERNAL (node->decl) || !node->output_to_lto_symbol_table_p ())
 	continue;
       write_symbol (cache, node->decl, &seen, false);
     }
@@ -2690,7 +2648,7 @@ produce_symtab (struct output_block *ob)
     {
       symtab_node *node = lsei_node (lsei);
 
-      if (!output_symbol_p (node) || !DECL_EXTERNAL (node->decl))
+      if (!DECL_EXTERNAL (node->decl) || !node->output_to_lto_symbol_table_p ())
 	continue;
       write_symbol (cache, node->decl, &seen, false);
     }
diff --git a/gcc/lto/ChangeLog b/gcc/lto/ChangeLog
index d090145bd3c..e6faf9420b7 100644
--- a/gcc/lto/ChangeLog
+++ b/gcc/lto/ChangeLog
@@ -1,6 +1,16 @@
 2018-03-06  Martin Liska  <mliska@suse.cz>
 
 	Backport from mainline
+	2018-02-08  Jan Hubicka  <hubicka@ucw.cz>
+
+	PR ipa/81360
+	* lto.c (unify_scc): Register prevailing trees, not trees to be freed.
+	(read_cgraph_and_symbols): Use
+	symtab_node::output_to_lto_symbol_table_p.
+
+2018-03-06  Martin Liska  <mliska@suse.cz>
+
+	Backport from mainline
 	2018-01-30  Jan Hubicka  <hubicka@ucw.cz>
 
 	* lto.c (register_resolution): Remove forgotten sanity check.
diff --git a/gcc/lto/lto.c b/gcc/lto/lto.c
index e6b58ef197a..8a82f923b6e 100644
--- a/gcc/lto/lto.c
+++ b/gcc/lto/lto.c
@@ -1638,13 +1638,16 @@ unify_scc (struct data_in *data_in, unsigned from,
 		{
 		  map2[i*2] = (tree)(uintptr_t)(from + i);
 		  map2[i*2+1] = scc->entries[i];
-		  lto_maybe_register_decl (data_in, scc->entries[i], from + i);
 		}
 	      qsort (map2, len, 2 * sizeof (tree), cmp_tree);
 	      qsort (map, len, 2 * sizeof (tree), cmp_tree);
 	      for (unsigned i = 0; i < len; ++i)
-		streamer_tree_cache_replace_tree (cache, map[2*i],
-						  (uintptr_t)map2[2*i]);
+		{
+		  lto_maybe_register_decl (data_in, map[2*i],
+					   (uintptr_t)map2[2*i]);
+		  streamer_tree_cache_replace_tree (cache, map[2*i],
+						    (uintptr_t)map2[2*i]);
+		}
 	    }
 
 	  /* Free the tree nodes from the read SCC.  */
@@ -2886,8 +2889,12 @@ read_cgraph_and_symbols (unsigned nfiles, const char **fnames)
 
 	res = snode->lto_file_data->resolution_map->get (snode->decl);
 	if (!res || *res == LDPR_UNKNOWN)
-	  fatal_error (input_location, "missing resolution data for %s",
-		       IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (snode->decl)));
+	  {
+	    if (snode->output_to_lto_symbol_table_p ())
+	      fatal_error (input_location, "missing resolution data for %s",
+		           IDENTIFIER_POINTER
+			     (DECL_ASSEMBLER_NAME (snode->decl)));
+	  }
 	else
           snode->resolution = *res;
       }
diff --git a/gcc/symtab.c b/gcc/symtab.c
index 342cc36f3af..c18f1b25199 100644
--- a/gcc/symtab.c
+++ b/gcc/symtab.c
@@ -35,6 +35,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "output.h"
 #include "ipa-utils.h"
 #include "calls.h"
+#include "builtins.h"
 
 static const char *ipa_ref_use_name[] = {"read","write","addr","alias","chkp"};
 
@@ -2279,3 +2280,58 @@ symtab_node::binds_to_current_def_p (symtab_node *ref)
 
   return false;
 }
+
+/* Return true if symbol should be output to the symbol table.  */
+
+bool
+symtab_node::output_to_lto_symbol_table_p (void)
+{
+  /* Only externally visible symbols matter.  */
+  if (!TREE_PUBLIC (decl))
+    return false;
+  if (!real_symbol_p ())
+    return false;
+  /* FIXME: variables probably should not be considered as real symbols at
+     first place.  */
+  if (VAR_P (decl) && DECL_HARD_REGISTER (decl))
+    return false;
+  /* FIXME: Builtins corresponding to real functions probably should have
+     symbol table entries.  */
+  if (is_builtin_fn (decl))
+    return false;
+
+  /* We have real symbol that should be in symbol table.  However try to trim
+     down the refernces to libraries bit more because linker will otherwise
+     bring unnecesary object files into the final link.
+     FIXME: The following checks can easily be confused i.e. by self recursive
+     function or self-referring variable.  */
+
+  /* We keep external functions in symtab for sake of inlining
+     and devirtualization.  We do not want to see them in symbol table as
+     references unless they are really used.  */
+  cgraph_node *cnode = dyn_cast <cgraph_node *> (this);
+  if (cnode && (!definition || DECL_EXTERNAL (decl))
+      && cnode->callers)
+    return true;
+
+ /* Ignore all references from external vars initializers - they are not really
+    part of the compilation unit until they are used by folding.  Some symbols,
+    like references to external construction vtables can not be referred to at
+    all.  We decide this at can_refer_decl_in_current_unit_p.  */
+ if (!definition || DECL_EXTERNAL (decl))
+    {
+      int i;
+      struct ipa_ref *ref;
+      for (i = 0; iterate_referring (i, ref); i++)
+	{
+	  if (ref->use == IPA_REF_ALIAS)
+	    continue;
+          if (is_a <cgraph_node *> (ref->referring))
+	    return true;
+	  if (!DECL_EXTERNAL (ref->referring->decl))
+	    return true;
+	}
+      return false;
+    }
+  return true;
+}
diff --git a/gcc/tree.c b/gcc/tree.c
index 698213c3501..0e98f53af96 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -5454,9 +5454,10 @@ free_lang_data_in_decl (tree decl)
 	 At this point, it is not needed anymore.  */
       DECL_SAVED_TREE (decl) = NULL_TREE;
 
-      /* Clear the abstract origin if it refers to a method.  Otherwise
-         dwarf2out.c will ICE as we clear TYPE_METHODS and thus the
-	 origin will not be output correctly.  */
+      /* Clear the abstract origin if it refers to a method.
+         Otherwise dwarf2out.c will ICE as we splice functions out of
+         TYPE_FIELDS and thus the origin will not be output
+         correctly.  */
       if (DECL_ABSTRACT_ORIGIN (decl)
 	  && DECL_CONTEXT (DECL_ABSTRACT_ORIGIN (decl))
 	  && RECORD_OR_UNION_TYPE_P