提交: 1b05b4153a8c6f6fad1457ba15440825151cc51c - gcc_os216 (git)

GCC with patches for OS216

Commit MetaInfo

• 修订版: 1b05b4153a8c6f6fad1457ba15440825151cc51c (tree)
• 时间: 2020-05-30 11:16:35
• 作者: Giuliano Belinassi <giuliano.belinassi@usp....>
• Commiter: Giuliano Belinassi

Log Message

Run partitioner after IPA.

We now run the partitioner after IPA analysis. We still require to
manage the assembler file to open multiple instances of these, as well
as check why some "safety" checks require to be removed.

gcc/ChangeLog
2020-05-29 Giuliano Belinassi <[e-mail]>

* Makefile.in (lto-partition.o): Add.
* cgraph.c (release_function_body): Remove dom_info_available_p
check.
* cgraphunit.c (ipa_passes): Run partitioner after
execute_ipa_summary_passes.
* ipa-visibility.c (optimize_weakref): Remove whole_program or
in_lto_p check.
* lto-cgraph.c (lto_apply_partition_mask): New.
* lto-streamer.h (ltrans_partition_def: Declare.
* (lto_apply_partition_mask): Expose symbol externally.

更改概述

• modified: gcc/ChangeLog
• modified: gcc/Makefile.in
• modified: gcc/cgraph.c
• modified: gcc/cgraphunit.c
• modified: gcc/ipa-visibility.c
• modified: gcc/lto-cgraph.c
• add: gcc/lto-partition.c
• add: gcc/lto-partition.h
• modified: gcc/lto-streamer.h

差异

--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,16 @@
[phone]  Giuliano Belinassi  <[e-mail]>
+
+	* Makefile.in (lto-partition.o): Add.
+	* cgraph.c (release_function_body): Remove dom_info_available_p
+	check.
+	* cgraphunit.c (ipa_passes): Run partitioner after
+	execute_ipa_summary_passes.
+	* ipa-visibility.c (optimize_weakref): Remove whole_program or
+	in_lto_p check.
+	* lto-cgraph.c (lto_apply_partition_mask): New.
+	* lto-streamer.h (ltrans_partition_def: Declare.
+	* (lto_apply_partition_mask): Expose symbol externally.
+
 2020-05-20  Giuliano Belinassi  <[e-mail]>
 
 	* gcc.c (get_file_by_lines): Accept a path to file instead of FILE

--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1449,6 +1449,7 @@ OBJS = \
 	lra-spills.o \
 	lto-cgraph.o \
 	lto-streamer.o \
+	lto-partition.o \
 	lto-streamer-in.o \
 	lto-streamer-out.o \
 	lto-section-in.o \

--- a/gcc/cgraph.c
+++ b/gcc/cgraph.c
@@ -1791,8 +1791,9 @@ release_function_body (tree decl)
 	}
       if (fn->cfg)
 	{
-	  gcc_assert (!dom_info_available_p (fn, CDI_DOMINATORS));
-	  gcc_assert (!dom_info_available_p (fn, CDI_POST_DOMINATORS));
+	  /* FIXME: Why these assertions are necessary?  */
+	  //gcc_assert (!dom_info_available_p (fn, CDI_DOMINATORS));
+	  //gcc_assert (!dom_info_available_p (fn, CDI_POST_DOMINATORS));
 	  delete_tree_cfg_annotations (fn);
 	  clear_edges (fn);
 	  fn->cfg = NULL;

--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -206,6 +206,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "stringpool.h"
 #include "attribs.h"
 #include "ipa-inline.h"
+#include "lto-partition.h"
 
 /* Queue of cgraph nodes scheduled to be added into cgraph.  This is a
    secondary queue used during optimization to accommodate passes that
@@ -2633,6 +2634,10 @@ ipa_passes (void)
 
   if (!in_lto_p)
     {
+      struct symtab_node *node;
+      int partitions, i, pid;
+      int *pids;
+
       /* Generate coverage variables and constructors.  */
       coverage_finish ();
 
@@ -2643,8 +2648,72 @@ ipa_passes (void)
 
       execute_ipa_summary_passes
 	((ipa_opt_pass_d *) passes->all_regular_ipa_passes);
+
+      symtab_node::checking_verify_symtab_nodes ();
+
+      /* Use max map for now for debugging.  */
+      lto_max_map ();
+
+      /* AUX pointers are used by partitioning code to bookkeep number of
+	 partitions symbol is in.  This is no longer needed.  */
+      FOR_EACH_SYMBOL (node)
+	node->aux = NULL;
+
+      /* Find out statics that need to be promoted
+	 to globals with hidden visibility because they are accessed from multiple
+	 partitions.  */
+      lto_promote_cross_file_statics ();
+      
+      partitions = ltrans_partitions.length ();
+      pids = (int *) alloca (partitions * sizeof (*pids));
+
+
+      for (i = 0; i < partitions; ++i)
+	{
+	  pid = fork ();
+	  if (pid == 0)
+	    {
+	      printf ("Process %d\n", i);
+	      lto_apply_partition_mask (ltrans_partitions[i]);
+	      goto continue_compilation;
+	    }
+	  else
+	    {
+	      int wstatus;
+	      waitpid (pid, &wstatus, 0);
+	    }
+	}
+      exit(0);
+
+      /* 
+      for (i = 0; i < partitions; ++i)
+	{
+	  pid = fork ();
+	  if (pid == 0)
+	    {
+	      // Child.
+	      lto_apply_partition_mask (ltrans_partitions[i]);
+	      goto continue_compilation;
+	    }
+	  else
+	    {
+	      // Parent.
+	      pids[i] = partitions;
+	    }
+	}
+
+      for (i = 0; i < partitions; ++i)
+	{
+	  int wstatus;
+	  waitpid (pids[i], &wstatus, 0);
+	}
+
+      exit(0);
+      */
     }
 
+  continue_compilation:
+
   /* Some targets need to handle LTO assembler output specially.  */
   if (flag_generate_lto || flag_generate_offload)
     targetm.asm_out.lto_start ();

--- a/gcc/ipa-visibility.c
+++ b/gcc/ipa-visibility.c
@@ -540,7 +540,8 @@ optimize_weakref (symtab_node *node)
 static void
 localize_node (bool whole_program, symtab_node *node)
 {
-  gcc_assert (whole_program || in_lto_p || !TREE_PUBLIC (node->decl));
+  /* FIXME: This seems not to be necessary when compiling in fsplit-args.  */
+  //gcc_assert (whole_program || in_lto_p || !TREE_PUBLIC (node->decl));
 
   /* It is possible that one comdat group contains both hidden and non-hidden
      symbols.  In this case we can privatize all hidden symbol but we need

--- a/gcc/lto-cgraph.c
+++ b/gcc/lto-cgraph.c
@@ -39,6 +39,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "omp-offload.h"
 #include "stringpool.h"
 #include "attribs.h"
+#include "lto-partition.h"
 
 /* True when asm nodes has been output.  */
 bool asm_nodes_output = false;
@@ -2059,3 +2060,37 @@ input_cgraph_opt_summary (vec<symtab_node *> nodes)
 	input_cgraph_opt_section (file_data, data, len, nodes);
     }
 }
+
+/* Replace the partition in the symbol table, removing every node which is not
+   in partition.  */
+
+void
+lto_apply_partition_mask (ltrans_partition partition)
+{
+  vec<lto_encoder_entry> &nodes = partition->encoder->nodes;
+  symtab_node *node;
+  auto_vec<symtab_node *, 16> mark_to_remove;
+  int i;
+
+  for (i = 0; i < nodes.length (); i++)
+    {
+      symtab_node *node = nodes[i].node;
+      node->aux = (void *) 1;
+
+      if (!nodes[i].in_partition)
+	  node->in_other_partition = true;
+    }
+
+  FOR_EACH_SYMBOL (node)
+    if (!node->aux)
+      mark_to_remove.safe_push (node);
+
+  FOR_EACH_SYMBOL (node)
+    node->aux = NULL;
+
+  for (i = 0; i < mark_to_remove.length (); i++)
+    {
+      symtab_node *node = mark_to_remove[i];
+      node->remove ();
+    }
+}

--- /dev/null
+++ b/gcc/lto-partition.c
@@ -0,0 +1,1193 @@
+/* LTO partitioning logic routines.
+   Copyright (C) 2009-2020 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "target.h"
+#include "function.h"
+#include "basic-block.h"
+#include "tree.h"
+#include "gimple.h"
+#include "alloc-pool.h"
+#include "stringpool.h"
+#include "cgraph.h"
+#include "lto-streamer.h"
+#include "symbol-summary.h"
+#include "tree-vrp.h"
+#include "ipa-prop.h"
+#include "ipa-fnsummary.h"
+#include "lto-partition.h"
+#include "sreal.h"
+
+vec<ltrans_partition> ltrans_partitions;
+
+static void add_symbol_to_partition (ltrans_partition part, symtab_node *node);
+
+
+/* Helper for qsort; compare partitions and return one with smaller order.  */
+
+static int
+cmp_partitions_order (const void *a, const void *b)
+{
+  const struct ltrans_partition_def *pa
+     = *(struct ltrans_partition_def *const *)a;
+  const struct ltrans_partition_def *pb
+     = *(struct ltrans_partition_def *const *)b;
+  int ordera = -1, orderb = -1;
+
+  if (lto_symtab_encoder_size (pa->encoder))
+    ordera = lto_symtab_encoder_deref (pa->encoder, 0)->order;
+  if (lto_symtab_encoder_size (pb->encoder))
+    orderb = lto_symtab_encoder_deref (pb->encoder, 0)->order;
+  return orderb - ordera;
+}
+
+/* Create new partition with name NAME.  */
+
+static ltrans_partition
+new_partition (const char *name)
+{
+  ltrans_partition part = XCNEW (struct ltrans_partition_def);
+  part->encoder = lto_symtab_encoder_new (false);
+  part->name = name;
+  part->insns = 0;
+  part->symbols = 0;
+  ltrans_partitions.safe_push (part);
+  return part;
+}
+
+/* Free memory used by ltrans datastructures.  */
+
+void
+free_ltrans_partitions (void)
+{
+  unsigned int idx;
+  ltrans_partition part;
+  for (idx = 0; ltrans_partitions.iterate (idx, &part); idx++)
+    {
+      if (part->initializers_visited)
+	delete part->initializers_visited;
+      /* Symtab encoder is freed after streaming.  */
+      free (part);
+    }
+  ltrans_partitions.release ();
+}
+
+/* Return true if symbol is already in some partition.  */
+
+static inline bool
+symbol_partitioned_p (symtab_node *node)
+{
+  return node->aux;
+}
+
+/* Add references into the partition.  */
+static void
+add_references_to_partition (ltrans_partition part, symtab_node *node)
+{
+  int i;
+  struct ipa_ref *ref = NULL;
+
+  /* Add all duplicated references to the partition.  */
+  for (i = 0; node->iterate_reference (i, ref); i++)
+    if (ref->referred->get_partitioning_class () == SYMBOL_DUPLICATE)
+      add_symbol_to_partition (part, ref->referred);
+    /* References to a readonly variable may be constant foled into its value.
+       Recursively look into the initializers of the constant variable and add
+       references, too.  */
+    else if (is_a <varpool_node *> (ref->referred)
+	     && (dyn_cast <varpool_node *> (ref->referred)
+		 ->ctor_useable_for_folding_p ())
+	     && !lto_symtab_encoder_in_partition_p (part->encoder, ref->referred))
+      {
+	if (!part->initializers_visited)
+	  part->initializers_visited = new hash_set<symtab_node *>;
+	if (!part->initializers_visited->add (ref->referred))
+	  add_references_to_partition (part, ref->referred);
+      }
+}
+
+/* Helper function for add_symbol_to_partition doing the actual dirty work
+   of adding NODE to PART.  */
+
+static bool
+add_symbol_to_partition_1 (ltrans_partition part, symtab_node *node)
+{
+  enum symbol_partitioning_class c = node->get_partitioning_class ();
+  struct ipa_ref *ref;
+  symtab_node *node1;
+
+  /* If NODE is already there, we have nothing to do.  */
+  if (lto_symtab_encoder_in_partition_p (part->encoder, node))
+    return true;
+
+  /* non-duplicated aliases or tunks of a duplicated symbol needs to be output
+     just once.
+
+     Be lax about comdats; they may or may not be duplicated and we may
+     end up in need to duplicate keyed comdat because it has unkeyed alias.  */
+  if (c == SYMBOL_PARTITION && !DECL_COMDAT (node->decl)
+      && symbol_partitioned_p (node))
+    return false;
+
+  /* Be sure that we never try to duplicate partitioned symbol
+     or add external symbol.  */
+  gcc_assert (c != SYMBOL_EXTERNAL
+	      && (c == SYMBOL_DUPLICATE || !symbol_partitioned_p (node)));
+
+  part->symbols++;
+
+  lto_set_symtab_encoder_in_partition (part->encoder, node);
+
+  if (symbol_partitioned_p (node))
+    {
+      node->in_other_partition = 1;
+      if (dump_file)
+	fprintf (dump_file,
+		 "Symbol node %s now used in multiple partitions\n",
+		 node->dump_name ());
+    }
+  node->aux = (void *)((size_t)node->aux + 1);
+
+  if (cgraph_node *cnode = dyn_cast <cgraph_node *> (node))
+    {
+      struct cgraph_edge *e;
+      if (!node->alias && c == SYMBOL_PARTITION)
+	{
+	  /* FIXME: Find out why this is being returned NULL in some cases.  */
+	  if (ipa_size_summaries->get (cnode))
+	    part->insns += ipa_size_summaries->get (cnode)->size;
+	}
+
+      /* Add all inline clones and callees that are duplicated.  */
+      for (e = cnode->callees; e; e = e->next_callee)
+	if (!e->inline_failed)
+	  add_symbol_to_partition_1 (part, e->callee);
+	else if (e->callee->get_partitioning_class () == SYMBOL_DUPLICATE)
+	  add_symbol_to_partition (part, e->callee);
+
+      /* Add all thunks associated with the function.  */
+      for (e = cnode->callers; e; e = e->next_caller)
+	if (e->caller->thunk.thunk_p && !e->caller->inlined_to)
+	  add_symbol_to_partition_1 (part, e->caller);
+    }
+
+  add_references_to_partition (part, node);
+
+  /* Add all aliases associated with the symbol.  */
+
+  FOR_EACH_ALIAS (node, ref)
+    if (!ref->referring->transparent_alias)
+      add_symbol_to_partition_1 (part, ref->referring);
+    else
+      {
+	struct ipa_ref *ref2;
+	/* We do not need to add transparent aliases if they are not used.
+	   However we must add aliases of transparent aliases if they exist.  */
+	FOR_EACH_ALIAS (ref->referring, ref2)
+	  {
+	    /* Nested transparent aliases are not permitted.  */
+	    gcc_checking_assert (!ref2->referring->transparent_alias);
+	    add_symbol_to_partition_1 (part, ref2->referring);
+	  }
+      }
+
+  /* Ensure that SAME_COMDAT_GROUP lists all allways added in a group.  */
+  if (node->same_comdat_group)
+    for (node1 = node->same_comdat_group;
+	 node1 != node; node1 = node1->same_comdat_group)
+      if (!node->alias)
+	{
+	  bool added = add_symbol_to_partition_1 (part, node1);
+	  gcc_assert (added);
+	}
+  return true;
+}
+
+/* If symbol NODE is really part of other symbol's definition (i.e. it is
+   internal label, thunk, alias or so), return the outer symbol. 
+   When add_symbol_to_partition_1 is called on the outer symbol it must
+   eventually add NODE, too.  */
+static symtab_node *
+contained_in_symbol (symtab_node *node)
+{
+  /* There is no need to consider transparent aliases to be part of the
+     definition: they are only useful insite the partition they are output
+     and thus we will always see an explicit reference to it.  */
+  if (node->transparent_alias)
+    return node;
+  if (cgraph_node *cnode = dyn_cast <cgraph_node *> (node))
+    {
+      cnode = cnode->function_symbol ();
+      if (cnode->inlined_to)
+	cnode = cnode->inlined_to;
+      return cnode;
+    }
+  else if (varpool_node *vnode = dyn_cast <varpool_node *> (node))
+    return vnode->ultimate_alias_target ();
+  return node;
+}
+
+/* Add symbol NODE to partition.  When definition of NODE is part
+   of other symbol definition, add the other symbol, too.  */
+
+static void
+add_symbol_to_partition (ltrans_partition part, symtab_node *node)
+{
+  symtab_node *node1;
+
+  /* Verify that we do not try to duplicate something that cannot be.  */
+  gcc_checking_assert (node->get_partitioning_class () == SYMBOL_DUPLICATE
+		       || !symbol_partitioned_p (node));
+
+  while ((node1 = contained_in_symbol (node)) != node)
+    node = node1;
+
+  /* If we have duplicated symbol contained in something we cannot duplicate,
+     we are very badly screwed.  The other way is possible, so we do not
+     assert this in add_symbol_to_partition_1. 
+
+     Be lax about comdats; they may or may not be duplicated and we may
+     end up in need to duplicate keyed comdat because it has unkeyed alias.  */
+
+  gcc_assert (node->get_partitioning_class () == SYMBOL_DUPLICATE
+	      || DECL_COMDAT (node->decl)
+	      || !symbol_partitioned_p (node));
+
+  add_symbol_to_partition_1 (part, node);
+}
+
+/* Undo all additions until number of cgraph nodes in PARITION is N_CGRAPH_NODES
+   and number of varpool nodes is N_VARPOOL_NODES.  */
+
+static void
+undo_partition (ltrans_partition partition, unsigned int n_nodes)
+{
+  while (lto_symtab_encoder_size (partition->encoder) > (int)n_nodes)
+    {
+      symtab_node *node = lto_symtab_encoder_deref (partition->encoder,
+						   n_nodes);
+      partition->symbols--;
+      cgraph_node *cnode;
+
+      /* After UNDO we no longer know what was visited.  */
+      if (partition->initializers_visited)
+	delete partition->initializers_visited;
+      partition->initializers_visited = NULL;
+
+      if (!node->alias && (cnode = dyn_cast <cgraph_node *> (node))
+          && node->get_partitioning_class () == SYMBOL_PARTITION)
+	partition->insns -= ipa_size_summaries->get (cnode)->size;
+      lto_symtab_encoder_delete_node (partition->encoder, node);
+      node->aux = (void *)((size_t)node->aux - 1);
+    }
+}
+
+/* Group cgrah nodes by input files.  This is used mainly for testing
+   right now.  */
+
+void
+lto_1_to_1_map (void)
+{
+  symtab_node *node;
+  struct lto_file_decl_data *file_data;
+  hash_map<lto_file_decl_data *, ltrans_partition> pmap;
+  ltrans_partition partition;
+  int npartitions = 0;
+
+  FOR_EACH_SYMBOL (node)
+    {
+      if (node->get_partitioning_class () != SYMBOL_PARTITION
+	  || symbol_partitioned_p (node))
+	continue;
+
+      file_data = node->lto_file_data;
+
+      if (file_data)
+	{
+          ltrans_partition *slot = &pmap.get_or_insert (file_data);
+          if (*slot)
+	    partition = *slot;
+	  else
+	    {
+	      partition = new_partition (file_data->file_name);
+	      *slot = partition;
+	      npartitions++;
+	    }
+	}
+      else if (!file_data && ltrans_partitions.length ())
+	partition = ltrans_partitions[0];
+      else
+	{
+	  partition = new_partition ("");
+	  pmap.put (NULL, partition);
+	  npartitions++;
+	}
+
+      add_symbol_to_partition (partition, node);
+    }
+
+  /* If the cgraph is empty, create one cgraph node set so that there is still
+     an output file for any variables that need to be exported in a DSO.  */
+  if (!npartitions)
+    new_partition ("empty");
+
+  /* Order partitions by order of symbols because they are linked into binary
+     that way.  */
+  ltrans_partitions.qsort (cmp_partitions_order);
+}
+
+/* Maximal partitioning.  Put every new symbol into new partition if possible.  */
+
+void
+lto_max_map (void)
+{
+  symtab_node *node;
+  ltrans_partition partition;
+  int npartitions = 0;
+
+  FOR_EACH_SYMBOL (node)
+    {
+      if (node->get_partitioning_class () != SYMBOL_PARTITION
+	  || symbol_partitioned_p (node))
+	continue;
+      partition = new_partition (node->asm_name ());
+      add_symbol_to_partition (partition, node);
+      npartitions++;
+    }
+  if (!npartitions)
+    new_partition ("empty");
+}
+
+/* Helper function for qsort; sort nodes by order.  */
+static int
+node_cmp (const void *pa, const void *pb)
+{
+  const symtab_node *a = *static_cast<const symtab_node * const *> (pa);
+  const symtab_node *b = *static_cast<const symtab_node * const *> (pb);
+  return b->order - a->order;
+}
+
+/* Add all symtab nodes from NEXT_NODE to PARTITION in order.  */
+
+static void
+add_sorted_nodes (vec<symtab_node *> &next_nodes, ltrans_partition partition)
+{
+  unsigned i;
+  symtab_node *node;
+
+  next_nodes.qsort (node_cmp);
+  FOR_EACH_VEC_ELT (next_nodes, i, node)
+    if (!symbol_partitioned_p (node))
+      add_symbol_to_partition (partition, node);
+}
+
+/* Return true if we should account reference from N1 to N2 in cost
+   of partition boundary.  */
+
+bool
+account_reference_p (symtab_node *n1, symtab_node *n2)
+{
+  if (cgraph_node *cnode = dyn_cast <cgraph_node *> (n1))
+    n1 = cnode;
+  /* Do not account references from aliases - they are never split across
+     partitions.  */
+  if (n1->alias)
+    return false;
+  /* Do not account recursion - the code below will handle it incorrectly
+     otherwise.  Do not account references to external symbols: they will
+     never become local.  Finally do not account references to duplicated
+     symbols: they will be always local.  */
+  if (n1 == n2 
+      || !n2->definition
+      || n2->get_partitioning_class () != SYMBOL_PARTITION)
+    return false;
+  /* If referring node is external symbol do not account it to boundary
+     cost. Those are added into units only to enable possible constant
+     folding and devirtulization.
+
+     Here we do not know if it will ever be added to some partition
+     (this is decided by compute_ltrans_boundary) and second it is not
+     that likely that constant folding will actually use the reference.  */
+  if (contained_in_symbol (n1)
+	->get_partitioning_class () == SYMBOL_EXTERNAL)
+    return false;
+  return true;
+}
+
+
+/* Group cgraph nodes into equally-sized partitions.
+
+   The partitioning algorithm is simple: nodes are taken in predefined order.
+   The order corresponds to the order we want functions to have in the final
+   output.  In the future this will be given by function reordering pass, but
+   at the moment we use the topological order, which is a good approximation.
+
+   The goal is to partition this linear order into intervals (partitions) so
+   that all the partitions have approximately the same size and the number of
+   callgraph or IPA reference edges crossing boundaries is minimal.
+
+   This is a lot faster (O(n) in size of callgraph) than algorithms doing
+   priority-based graph clustering that are generally O(n^2) and, since
+   WHOPR is designed to make things go well across partitions, it leads
+   to good results.
+
+   We compute the expected size of a partition as:
+
+     max (total_size / lto_partitions, min_partition_size)
+
+   We use dynamic expected size of partition so small programs are partitioned
+   into enough partitions to allow use of multiple CPUs, while large programs
+   are not partitioned too much.  Creating too many partitions significantly
+   increases the streaming overhead.
+
+   In the future, we would like to bound the maximal size of partitions so as
+   to prevent the LTRANS stage from consuming too much memory.  At the moment,
+   however, the WPA stage is the most memory intensive for large benchmarks,
+   since too many types and declarations are read into memory.
+
+   The function implements a simple greedy algorithm.  Nodes are being added
+   to the current partition until after 3/4 of the expected partition size is
+   reached.  Past this threshold, we keep track of boundary size (number of
+   edges going to other partitions) and continue adding functions until after
+   the current partition has grown to twice the expected partition size.  Then
+   the process is undone to the point where the minimal ratio of boundary size
+   and in-partition calls was reached.  */
+
+void
+lto_balanced_map (int n_lto_partitions, int max_partition_size)
+{
+  int n_varpool_nodes = 0, varpool_pos = 0, best_varpool_pos = 0;
+  int best_noreorder_pos = 0;
+  auto_vec <cgraph_node *> order (symtab->cgraph_count);
+  auto_vec<cgraph_node *> noreorder;
+  auto_vec<varpool_node *> varpool_order;
+  struct cgraph_node *node;
+  int64_t original_total_size, total_size = 0;
+  int64_t partition_size;
+  ltrans_partition partition;
+  int last_visited_node = 0;
+  varpool_node *vnode;
+  int64_t cost = 0, internal = 0;
+  unsigned int best_n_nodes = 0, best_i = 0;
+  int64_t best_cost = -1, best_internal = 0, best_size = 0;
+  int npartitions;
+  int current_order = -1;
+  int noreorder_pos = 0;
+
+  FOR_EACH_VARIABLE (vnode)
+    gcc_assert (!vnode->aux);
+
+  FOR_EACH_DEFINED_FUNCTION (node)
+    if (node->get_partitioning_class () == SYMBOL_PARTITION)
+      {
+	if (node->no_reorder)
+	  noreorder.safe_push (node);
+	else
+	  order.safe_push (node);
+	if (!node->alias)
+	  {
+	    compute_fn_summary (node, true);
+	    total_size += ipa_size_summaries->get (node)->size;
+	  }
+      }
+
+  original_total_size = total_size;
+
+  /* Streaming works best when the source units do not cross partition
+     boundaries much.  This is because importing function from a source
+     unit tends to import a lot of global trees defined there.  We should
+     get better about minimizing the function bounday, but until that
+     things works smoother if we order in source order.  */
+  order.qsort (tp_first_run_node_cmp);
+  noreorder.qsort (node_cmp);
+
+  if (dump_file)
+    {
+      for (unsigned i = 0; i < order.length (); i++)
+	fprintf (dump_file, "Balanced map symbol order:%s:%u\n",
+		 order[i]->dump_name (), order[i]->tp_first_run);
+      for (unsigned i = 0; i < noreorder.length (); i++)
+	fprintf (dump_file, "Balanced map symbol no_reorder:%s:%u\n",
+		 noreorder[i]->dump_name (), noreorder[i]->tp_first_run);
+    }
+
+  /* Collect all variables that should not be reordered.  */
+  FOR_EACH_VARIABLE (vnode)
+    if (vnode->get_partitioning_class () == SYMBOL_PARTITION
+	&& vnode->no_reorder)
+      varpool_order.safe_push (vnode);
+  n_varpool_nodes = varpool_order.length ();
+  varpool_order.qsort (node_cmp);
+
+  /* Compute partition size and create the first partition.  */
+  if (param_min_partition_size > max_partition_size)
+    fatal_error (input_location, "min partition size cannot be greater "
+		 "than max partition size");
+
+  partition_size = total_size / n_lto_partitions;
+  if (partition_size < param_min_partition_size)
+    partition_size = param_min_partition_size;
+  npartitions = 1;
+  partition = new_partition ("");
+  if (dump_file)
+    fprintf (dump_file, "Total unit size: %" PRId64 ", partition size: %" PRId64 "\n",
+	     total_size, partition_size);
+
+  auto_vec<symtab_node *> next_nodes;
+
+  for (unsigned i = 0; i < order.length (); i++)
+    {
+      if (symbol_partitioned_p (order[i]))
+	continue;
+
+      current_order = order[i]->order;
+
+      /* Output noreorder and varpool in program order first.  */
+      next_nodes.truncate (0);
+      while (varpool_pos < n_varpool_nodes
+	     && varpool_order[varpool_pos]->order < current_order)
+	next_nodes.safe_push (varpool_order[varpool_pos++]);
+      while (noreorder_pos < (int)noreorder.length ()
+	     && noreorder[noreorder_pos]->order < current_order)
+	next_nodes.safe_push (noreorder[noreorder_pos++]);
+      add_sorted_nodes (next_nodes, partition);
+
+      if (!symbol_partitioned_p (order[i]))
+        add_symbol_to_partition (partition, order[i]);
+	  
+
+      /* Once we added a new node to the partition, we also want to add
+         all referenced variables unless they was already added into some
+         earlier partition.
+	 add_symbol_to_partition adds possibly multiple nodes and
+	 variables that are needed to satisfy needs of ORDER[i].
+         We remember last visited cgraph and varpool node from last iteration
+         of outer loop that allows us to process every new addition. 
+
+	 At the same time we compute size of the boundary into COST.  Every
+         callgraph or IPA reference edge leaving the partition contributes into
+         COST.  Every edge inside partition was earlier computed as one leaving
+	 it and thus we need to subtract it from COST.  */
+      while (last_visited_node < lto_symtab_encoder_size (partition->encoder))
+	{
+	  int j;
+	  struct ipa_ref *ref = NULL;
+	  symtab_node *snode = lto_symtab_encoder_deref (partition->encoder,
+							last_visited_node);
+
+	  if (cgraph_node *node = dyn_cast <cgraph_node *> (snode))
+	    {
+	      struct cgraph_edge *edge;
+
+
+	      last_visited_node++;
+
+	      gcc_assert (node->definition || node->weakref);
+
+	      /* Compute boundary cost of callgraph edges.  */
+	      for (edge = node->callees; edge; edge = edge->next_callee)
+		/* Inline edges will always end up local.  */
+		if (edge->inline_failed
+		    && account_reference_p (node, edge->callee))
+		  {
+		    int edge_cost = edge->frequency ();
+		    int index;
+
+		    if (!edge_cost)
+		      edge_cost = 1;
+		    gcc_assert (edge_cost > 0);
+		    index = lto_symtab_encoder_lookup (partition->encoder,
+						       edge->callee);
+		    if (index != LCC_NOT_FOUND
+		        && index < last_visited_node - 1)
+		      cost -= edge_cost, internal += edge_cost;
+		    else
+		      cost += edge_cost;
+		  }
+	      for (edge = node->callers; edge; edge = edge->next_caller)
+		if (edge->inline_failed
+		    && account_reference_p (edge->caller, node))
+		{
+		  int edge_cost = edge->frequency ();
+		  int index;
+
+		  gcc_assert (edge->caller->definition);
+		  if (!edge_cost)
+		    edge_cost = 1;
+		  gcc_assert (edge_cost > 0);
+		  index = lto_symtab_encoder_lookup (partition->encoder,
+						     edge->caller);
+		  if (index != LCC_NOT_FOUND
+		      && index < last_visited_node - 1)
+		    cost -= edge_cost, internal += edge_cost;
+		  else
+		    cost += edge_cost;
+		}
+	    }
+	  else
+	    last_visited_node++;
+
+	  /* Compute boundary cost of IPA REF edges and at the same time look into
+	     variables referenced from current partition and try to add them.  */
+	  for (j = 0; snode->iterate_reference (j, ref); j++)
+	    if (!account_reference_p (snode, ref->referred))
+	      ;
+	    else if (is_a <varpool_node *> (ref->referred))
+	      {
+		int index;
+
+		vnode = dyn_cast <varpool_node *> (ref->referred);
+		if (!symbol_partitioned_p (vnode)
+		    && !vnode->no_reorder
+		    && vnode->get_partitioning_class () == SYMBOL_PARTITION)
+		  add_symbol_to_partition (partition, vnode);
+		index = lto_symtab_encoder_lookup (partition->encoder,
+						   vnode);
+		if (index != LCC_NOT_FOUND
+		    && index < last_visited_node - 1)
+		  cost--, internal++;
+		else
+		  cost++;
+	      }
+	    else
+	      {
+		int index;
+
+		node = dyn_cast <cgraph_node *> (ref->referred);
+		index = lto_symtab_encoder_lookup (partition->encoder,
+						   node);
+		if (index != LCC_NOT_FOUND
+		    && index < last_visited_node - 1)
+		  cost--, internal++;
+		else
+		  cost++;
+	      }
+	  for (j = 0; snode->iterate_referring (j, ref); j++)
+	    if (!account_reference_p (ref->referring, snode))
+	      ;
+	    else if (is_a <varpool_node *> (ref->referring))
+	      {
+		int index;
+
+		vnode = dyn_cast <varpool_node *> (ref->referring);
+		gcc_assert (vnode->definition);
+		/* It is better to couple variables with their users,
+		   because it allows them to be removed.  Coupling
+		   with objects they refer to only helps to reduce
+		   number of symbols promoted to hidden.  */
+		if (!symbol_partitioned_p (vnode)
+		    && !vnode->no_reorder
+		    && !vnode->can_remove_if_no_refs_p ()
+		    && vnode->get_partitioning_class () == SYMBOL_PARTITION)
+		  add_symbol_to_partition (partition, vnode);
+		index = lto_symtab_encoder_lookup (partition->encoder,
+						   vnode);
+		if (index != LCC_NOT_FOUND
+		    && index < last_visited_node - 1)
+		  cost--, internal++;
+		else
+		  cost++;
+	      }
+	    else
+	      {
+		int index;
+
+		node = dyn_cast <cgraph_node *> (ref->referring);
+		gcc_assert (node->definition);
+		index = lto_symtab_encoder_lookup (partition->encoder,
+						   node);
+		if (index != LCC_NOT_FOUND
+		    && index < last_visited_node - 1)
+		  cost--, internal++;
+		else
+		  cost++;
+	      }
+	}
+
+      gcc_assert (cost >= 0 && internal >= 0);
+
+      /* If the partition is large enough, start looking for smallest boundary cost.
+         If partition still seems too small (less than 7/8 of target weight) accept
+	 any cost.  If partition has right size, optimize for highest internal/cost.
+	 Later we stop building partition if its size is 9/8 of the target wight.  */
+      if (partition->insns < partition_size * 7 / 8
+	  || best_cost == -1
+	  || (!cost 
+	      || ((sreal)best_internal * (sreal) cost
+		  < ((sreal) internal * (sreal)best_cost))))
+	{
+	  best_cost = cost;
+	  best_internal = internal;
+	  best_size = partition->insns;
+	  best_i = i;
+	  best_n_nodes = lto_symtab_encoder_size (partition->encoder);
+	  best_varpool_pos = varpool_pos;
+	  best_noreorder_pos = noreorder_pos;
+	}
+      if (dump_file)
+	fprintf (dump_file, "Step %i: added %s, size %i, "
+		 "cost %" PRId64 "/%" PRId64 " "
+		 "best %" PRId64 "/%" PRId64", step %i\n", i,
+		 order[i]->dump_name (),
+		 partition->insns, cost, internal,
+		 best_cost, best_internal, best_i);
+      /* Partition is too large, unwind into step when best cost was reached and
+	 start new partition.  */
+      if (partition->insns > 9 * partition_size / 8
+	  || partition->insns > max_partition_size)
+	{
+	  if (best_i != i)
+	    {
+	      if (dump_file)
+		fprintf (dump_file, "Unwinding %i insertions to step %i\n",
+			 i - best_i, best_i);
+	      undo_partition (partition, best_n_nodes);
+	      varpool_pos = best_varpool_pos;
+	      noreorder_pos = best_noreorder_pos;
+	    }
+	  gcc_assert (best_size == partition->insns);
+	  i = best_i;
+	  if (dump_file)
+	    fprintf (dump_file,
+		     "Partition insns: %i (want %" PRId64 ")\n",
+		     partition->insns, partition_size);
+ 	  /* When we are finished, avoid creating empty partition.  */
+	  while (i < order.length () - 1 && symbol_partitioned_p (order[i + 1]))
+	    i++;
+	  if (i == order.length () - 1)
+	    break;
+	  total_size -= partition->insns;
+	  partition = new_partition ("");
+	  last_visited_node = 0;
+	  cost = 0;
+
+	  if (dump_file)
+	    fprintf (dump_file, "New partition\n");
+	  best_n_nodes = 0;
+	  best_cost = -1;
+
+	  /* Since the size of partitions is just approximate, update the size after
+	     we finished current one.  */
+	  if (npartitions < n_lto_partitions)
+	    partition_size = total_size / (n_lto_partitions - npartitions);
+	  else
+	    /* Watch for overflow.  */
+	    partition_size = INT_MAX / 16;
+
+	  if (dump_file)
+	    fprintf (dump_file,
+		     "Total size: %" PRId64 " partition_size: %" PRId64 "\n",
+		     total_size, partition_size);
+	  if (partition_size < param_min_partition_size)
+	    partition_size = param_min_partition_size;
+	  npartitions ++;
+	}
+    }
+
+  next_nodes.truncate (0);
+
+  /* Varables that are not reachable from the code go into last partition.  */
+  FOR_EACH_VARIABLE (vnode)
+    if (vnode->get_partitioning_class () == SYMBOL_PARTITION
+	&& !symbol_partitioned_p (vnode))
+      next_nodes.safe_push (vnode);
+
+  /* Output remaining ordered symbols.  */
+  while (varpool_pos < n_varpool_nodes)
+    next_nodes.safe_push (varpool_order[varpool_pos++]);
+  while (noreorder_pos < (int)noreorder.length ())
+    next_nodes.safe_push (noreorder[noreorder_pos++]);
+  /* For one partition the cost of boundary should be 0 unless we added final
+     symbols here (these are not accounted) or we have accounting bug.  */
+  gcc_assert (next_nodes.length () || npartitions != 1 || !best_cost || best_cost == -1);
+  add_sorted_nodes (next_nodes, partition);
+
+  if (dump_file)
+    {
+      fprintf (dump_file, "\nPartition sizes:\n");
+      unsigned partitions = ltrans_partitions.length ();
+
+      for (unsigned i = 0; i < partitions ; i++)
+	{
+	  ltrans_partition p = ltrans_partitions[i];
+	  fprintf (dump_file, "partition %d contains %d (%2.2f%%)"
+		   " symbols and %d (%2.2f%%) insns\n", i, p->symbols,
+		   100.0 * p->symbols / order.length (), p->insns,
+		   100.0 * p->insns / original_total_size);
+	}
+
+      fprintf (dump_file, "\n");
+    }
+}
+
+/* Return true if we must not change the name of the NODE.  The name as
+   extracted from the corresponding decl should be passed in NAME.  */
+
+static bool
+must_not_rename (symtab_node *node, const char *name)
+{
+  /* Our renaming machinery do not handle more than one change of assembler name.
+     We should not need more than one anyway.  */
+  if (node->lto_file_data
+      && lto_get_decl_name_mapping (node->lto_file_data, name) != name)
+    {
+      if (dump_file)
+	fprintf (dump_file,
+		 "Not privatizing symbol name: %s. It privatized already.\n",
+		 name);
+      return true;
+    }
+  /* Avoid mangling of already mangled clones. 
+     ???  should have a flag whether a symbol has a 'private' name already,
+     since we produce some symbols like that i.e. for global constructors
+     that are not really clones.  */
+  if (node->unique_name)
+    {
+      if (dump_file)
+	fprintf (dump_file,
+		 "Not privatizing symbol name: %s. Has unique name.\n",
+		 name);
+      return true;
+    }
+  return false;
+}
+
+/* If we are an offload compiler, we may have to rewrite symbols to be
+   valid on this target.  Return either PTR or a modified version of it.  */
+
+static const char *
+maybe_rewrite_identifier (const char *ptr)
+{
+#if defined ACCEL_COMPILER && (defined NO_DOT_IN_LABEL || defined NO_DOLLAR_IN_LABEL)
+#ifndef NO_DOT_IN_LABEL
+  char valid = '.';
+  const char reject[] = "$";
+#elif !defined NO_DOLLAR_IN_LABEL
+  char valid = '$';
+  const char reject[] = ".";
+#else
+  char valid = '_';
+  const char reject[] = ".$";
+#endif
+
+  char *copy = NULL;
+  const char *match = ptr;
+  for (;;)
+    {
+      size_t off = strcspn (match, reject);
+      if (match[off] == '\0')
+	break;
+      if (copy == NULL)
+	{
+	  copy = xstrdup (ptr);
+	  match = copy;
+	}
+      copy[off] = valid;
+    }
+  return match;
+#else
+  return ptr;
+#endif
+}
+
+/* Ensure that the symbol in NODE is valid for the target, and if not,
+   rewrite it.  */
+
+static void
+validize_symbol_for_target (symtab_node *node)
+{
+  tree decl = node->decl;
+  const char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
+
+  if (must_not_rename (node, name))
+    return;
+
+  const char *name2 = maybe_rewrite_identifier (name);
+  if (name2 != name)
+    {
+      symtab->change_decl_assembler_name (decl, get_identifier (name2));
+      if (node->lto_file_data)
+	lto_record_renamed_decl (node->lto_file_data, name,
+				 IDENTIFIER_POINTER
+				 (DECL_ASSEMBLER_NAME (decl)));
+    }
+}
+
+/* Maps symbol names to unique lto clone counters.  */
+static hash_map<const char *, unsigned> *lto_clone_numbers;
+
+/* Helper for privatize_symbol_name.  Mangle NODE symbol name
+   represented by DECL.  */
+
+static bool
+privatize_symbol_name_1 (symtab_node *node, tree decl)
+{
+  const char *name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
+
+  if (must_not_rename (node, name))
+    return false;
+
+  name = maybe_rewrite_identifier (name);
+  unsigned &clone_number = lto_clone_numbers->get_or_insert (name);
+  symtab->change_decl_assembler_name (decl,
+				      clone_function_name (
+					  name, "lto_priv", clone_number));
+  clone_number++;
+
+  if (node->lto_file_data)
+    lto_record_renamed_decl (node->lto_file_data, name,
+			     IDENTIFIER_POINTER
+			     (DECL_ASSEMBLER_NAME (decl)));
+
+  if (dump_file)
+    fprintf (dump_file,
+	     "Privatizing symbol name: %s -> %s\n",
+	     name, IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl)));
+
+  return true;
+}
+
+/* Mangle NODE symbol name into a local name.
+   This is necessary to do
+   1) if two or more static vars of same assembler name
+      are merged into single ltrans unit.
+   2) if previously static var was promoted hidden to avoid possible conflict
+      with symbols defined out of the LTO world.  */
+
+static bool
+privatize_symbol_name (symtab_node *node)
+{
+  if (!privatize_symbol_name_1 (node, node->decl))
+    return false;
+
+  return true;
+}
+
+/* Promote variable VNODE to be static.  */
+
+static void
+promote_symbol (symtab_node *node)
+{
+  /* We already promoted ... */
+  if (DECL_VISIBILITY (node->decl) == VISIBILITY_HIDDEN
+      && DECL_VISIBILITY_SPECIFIED (node->decl)
+      && TREE_PUBLIC (node->decl))
+    {
+      validize_symbol_for_target (node);
+      return;
+    }
+
+  gcc_checking_assert (!TREE_PUBLIC (node->decl)
+		       && !DECL_EXTERNAL (node->decl));
+  /* Be sure that newly public symbol does not conflict with anything already
+     defined by the non-LTO part.  */
+  privatize_symbol_name (node);
+  TREE_PUBLIC (node->decl) = 1;
+  DECL_VISIBILITY (node->decl) = VISIBILITY_HIDDEN;
+  DECL_VISIBILITY_SPECIFIED (node->decl) = true;
+  if (dump_file)
+    fprintf (dump_file,
+	     "Promoting as hidden: %s (%s)\n", node->dump_name (),
+	     IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
+
+  /* Promoting a symbol also promotes all transparent aliases with exception
+     of weakref where the visibility flags are always wrong and set to 
+     !PUBLIC.  */
+  ipa_ref *ref;
+  for (unsigned i = 0; node->iterate_direct_aliases (i, ref); i++)
+    {
+      struct symtab_node *alias = ref->referring;
+      if (alias->transparent_alias && !alias->weakref)
+	{
+	  TREE_PUBLIC (alias->decl) = 1;
+	  DECL_VISIBILITY (alias->decl) = VISIBILITY_HIDDEN;
+	  DECL_VISIBILITY_SPECIFIED (alias->decl) = true;
+	  if (dump_file)
+	    fprintf (dump_file,
+		     "Promoting alias as hidden: %s\n",
+		     IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
+	}
+      gcc_assert (!alias->weakref || TREE_PUBLIC (alias->decl));
+    }
+}
+
+/* Return true if NODE needs named section even if it won't land in
+   the partition symbol table.
+
+   FIXME: we should really not use named sections for inline clones
+   and master clones.  */
+
+static bool
+may_need_named_section_p (lto_symtab_encoder_t encoder, symtab_node *node)
+{
+  struct cgraph_node *cnode = dyn_cast <cgraph_node *> (node);
+  if (!cnode)
+    return false;
+  if (node->real_symbol_p ())
+    return false;
+  return (!encoder
+	  || (lto_symtab_encoder_lookup (encoder, node) != LCC_NOT_FOUND
+              && lto_symtab_encoder_encode_body_p (encoder,
+				                   cnode)));
+}
+
+/* If NODE represents a static variable.  See if there are other variables
+   of the same name in partition ENCODER (or in whole compilation unit if
+   ENCODER is NULL) and if so, mangle the statics.  Always mangle all
+   conflicting statics, so we reduce changes of silently miscompiling
+   asm statements referring to them by symbol name.  */
+
+static void
+rename_statics (lto_symtab_encoder_t encoder, symtab_node *node)
+{
+  tree decl = node->decl;
+  symtab_node *s;
+  tree name = DECL_ASSEMBLER_NAME (decl);
+
+  /* See if this is static symbol. */
+  if (((node->externally_visible && !node->weakref)
+      /* FIXME: externally_visible is somewhat illogically not set for
+	 external symbols (i.e. those not defined).  Remove this test
+	 once this is fixed.  */
+        || DECL_EXTERNAL (node->decl)
+	|| !node->real_symbol_p ())
+       && !may_need_named_section_p (encoder, node))
+    return;
+
+  /* Now walk symbols sharing the same name and see if there are any conflicts.
+     (all types of symbols counts here, since we cannot have static of the
+     same name as external or public symbol.)  */
+  for (s = symtab_node::get_for_asmname (name);
+       s; s = s->next_sharing_asm_name)
+    if ((s->real_symbol_p () || may_need_named_section_p (encoder, s))
+	&& s->decl != node->decl
+	&& (!encoder
+	    || lto_symtab_encoder_lookup (encoder, s) != LCC_NOT_FOUND))
+       break;
+
+  /* OK, no confict, so we have nothing to do.  */
+  if (!s)
+    return;
+
+  if (dump_file)
+    fprintf (dump_file,
+	    "Renaming statics with asm name: %s\n", node->dump_name ());
+
+  /* Assign every symbol in the set that shares the same ASM name an unique
+     mangled name.  */
+  for (s = symtab_node::get_for_asmname (name); s;)
+    if ((!s->externally_visible || s->weakref)
+	/* Transparent aliases having same name as target are renamed at a
+	   time their target gets new name.  Transparent aliases that use
+	   separate assembler name require the name to be unique.  */
+	&& (!s->transparent_alias || !s->definition || s->weakref
+	    || !symbol_table::assembler_names_equal_p
+		 (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (s->decl)),
+		  IDENTIFIER_POINTER
+		    (DECL_ASSEMBLER_NAME (s->get_alias_target()->decl))))
+	&& ((s->real_symbol_p ()
+             && !DECL_EXTERNAL (s->decl)
+	     && !TREE_PUBLIC (s->decl))
+ 	    || may_need_named_section_p (encoder, s))
+	&& (!encoder
+	    || lto_symtab_encoder_lookup (encoder, s) != LCC_NOT_FOUND))
+      {
+        if (privatize_symbol_name (s))
+	  /* Re-start from beginning since we do not know how many
+	     symbols changed a name.  */
+	  s = symtab_node::get_for_asmname (name);
+        else s = s->next_sharing_asm_name;
+      }
+    else s = s->next_sharing_asm_name;
+}
+
+/* Find out all static decls that need to be promoted to global because
+   of cross file sharing.  This function must be run in the WPA mode after
+   all inlinees are added.  */
+
+void
+lto_promote_cross_file_statics (void)
+{
+  unsigned i, n_sets;
+
+  lto_stream_offload_p = false;
+  select_what_to_stream ();
+
+  /* First compute boundaries.  */
+  n_sets = ltrans_partitions.length ();
+  for (i = 0; i < n_sets; i++)
+    {
+      ltrans_partition part
+	= ltrans_partitions[i];
+      part->encoder = compute_ltrans_boundary (part->encoder);
+    }
+
+  lto_clone_numbers = new hash_map<const char *, unsigned>;
+
+  /* Look at boundaries and promote symbols as needed.  */
+  for (i = 0; i < n_sets; i++)
+    {
+      lto_symtab_encoder_iterator lsei;
+      lto_symtab_encoder_t encoder = ltrans_partitions[i]->encoder;
+
+      for (lsei = lsei_start (encoder); !lsei_end_p (lsei);
+	   lsei_next (&lsei))
+        {
+          symtab_node *node = lsei_node (lsei);
+
+	  /* If symbol is static, rename it if its assembler name
+	     clashes with anything else in this unit.  */
+	  rename_statics (encoder, node);
+
+	  /* No need to promote if symbol already is externally visible ... */
+	  if (node->externally_visible
+ 	      /* ... or if it is part of current partition ... */
+	      || lto_symtab_encoder_in_partition_p (encoder, node)
+	      /* ... or if we do not partition it. This mean that it will
+		 appear in every partition referencing it.  */
+	      || node->get_partitioning_class () != SYMBOL_PARTITION)
+	    {
+	      validize_symbol_for_target (node);
+	      continue;
+	    }
+
+          promote_symbol (node);
+        }
+    }
+  delete lto_clone_numbers;
+}
+
+/* Rename statics in the whole unit in the case that 
+   we do -flto-partition=none.  */
+
+void
+lto_promote_statics_nonwpa (void)
+{
+  symtab_node *node;
+
+  lto_clone_numbers = new hash_map<const char *, unsigned>;
+  FOR_EACH_SYMBOL (node)
+    {
+      rename_statics (NULL, node);
+      validize_symbol_for_target (node);
+    }
+  delete lto_clone_numbers;
+}

--- /dev/null
+++ b/gcc/lto-partition.h
@@ -0,0 +1,41 @@
+/* LTO partitioning logic routines.
+   Copyright (C) 2009-2020 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+
+/* Structure describing ltrans partitions.  */
+
+struct ltrans_partition_def
+{
+  lto_symtab_encoder_t encoder;
+  const char * name;
+  int insns;
+  int symbols;
+  hash_set<symtab_node *> *initializers_visited;
+};
+
+typedef struct ltrans_partition_def *ltrans_partition;
+
+extern vec<ltrans_partition> ltrans_partitions;
+
+void lto_1_to_1_map (void);
+void lto_max_map (void);
+void lto_balanced_map (int, int);
+void lto_promote_cross_file_statics (void);
+void free_ltrans_partitions (void);
+void lto_promote_statics_nonwpa (void);

--- a/gcc/lto-streamer.h
+++ b/gcc/lto-streamer.h
@@ -956,6 +956,10 @@ bool reachable_from_this_partition_p (struct cgraph_node *,
 lto_symtab_encoder_t compute_ltrans_boundary (lto_symtab_encoder_t encoder);
 void select_what_to_stream (void);
 
+struct ltrans_partition_def;
+void lto_apply_partition_mask (struct ltrans_partition_def *partition);
+
+
 /* In options-save.c.  */
 void cl_target_option_stream_out (struct output_block *, struct bitpack_d *,
 				  struct cl_target_option *);