Move nested function info out of cgraph_node

this patch moves nested function information out of symbol table (to a summary).
This saves memory (especially at WPA time) and also makes nested function
support more contained.

gcc/ChangeLog:

2020-10-22  Jan Hubicka  <hubicka@ucw.cz>

	* cgraph.c: Include tree-nested.h
	(cgraph_node::create): Call maybe_record_nested_function.
	(cgraph_node::remove): Do not remove function from nested function
	infos.
	(cgraph_node::dump): Update.
	(cgraph_node::unnest): Move to tree-nested.c
	(cgraph_node::verify_node): Update.
	(cgraph_c_finalize): Call nested_function_info::release.
	* cgraph.h (struct symtab_node): Remove nested function info.
	* cgraphclones.c (cgraph_node::create_clone): Do not clone nested
	function info.
	* cgraphunit.c (cgraph_node::analyze): Update.
	(cgraph_node::expand): Do not worry about nested functions; they are
	lowered.
	(symbol_table::finalize_compilation_unit): Call
	nested_function_info::release.
	* gimplify.c: Include tree-nested.h
	(unshare_body): Update.
	(unvisit_body): Update.
	* omp-offload.c (omp_discover_implicit_declare_target): Update.
	* tree-nested.c: Include alloc-pool.h, tree-nested.h, symbol-summary.h
	(nested_function_sum): New static variable.
	(nested_function_info::get): New member function.
	(nested_function_info::get_create): New member function.
	(unnest_function): New function.
	(nested_function_info::~nested_function_info): New member function.
	(nested_function_info::release): New function.
	(maybe_record_nested_function): New function.
	(lookup_element_for_decl): Update.
	(check_for_nested_with_variably_modified): Update.
	(create_nesting_tree): Update.
	(unnest_nesting_tree_1): Update.
	(gimplify_all_functions): Update.
	(lower_nested_functions): Update.
	* tree-nested.h (class nested_function_info): New class.
	(maybe_record_nested_function): Declare.
	(unnest_function): Declare.
	(first_nested_function): New inline function.
	(next_nested_function): New inline function.
	(nested_function_origin): New inline function.

gcc/ada/ChangeLog:

2020-10-22  Jan Hubicka  <hubicka@ucw.cz>

	* gcc-interface/trans.c: Include tree-nested.h
	(walk_nesting_tree): Update for new nested function info.

gcc/c-family/ChangeLog:

2020-10-22  Jan Hubicka  <hubicka@ucw.cz>

	* c-gimplify.c: Include tree-nested.h
	(c_genericize): Update for new nested function info.

gcc/d/ChangeLog:

2020-10-22  Jan Hubicka  <hubicka@ucw.cz>

	* decl.cc: Include tree-nested.h
	(get_symbol_decl): Update for new nested function info.

1 files changed, 62 insertions, 0 deletions

diff --git a/gcc/tree-nested.h b/gcc/tree-nested.h
index 4ee56f4..bdef416 100644
--- a/gcc/tree-nested.h
+++ b/gcc/tree-nested.h
@@ -24,4 +24,66 @@ extern tree build_addr (tree);
 extern void insert_field_into_struct (tree, tree);
 extern void lower_nested_functions (tree);
 
+class nested_function_info
+{
+public:
+  /* Constructor.  */
+  nested_function_info ()
+    : origin (NULL),
+      nested (NULL),
+      next_nested (NULL)
+  {
+  }
+  /* Copy constructor.  We can not simply copy the structure,
+     because the linked lists would go wrong.  However we should never
+     need that.  */
+  nested_function_info (const nested_function_info &)
+  {
+     gcc_unreachable ();
+  }
+  ~nested_function_info ();
+
+  /* Return nested_function_info, if available.  */
+  static nested_function_info *get (cgraph_node *node);
+
+  /* Return nested_function_info possibly creating new one.  */
+  static nested_function_info *get_create (cgraph_node *node);
+
+  /* Release all nested_function_infos.  */
+  static void release (void);
+
+  /* For nested functions points to function the node is nested in.  */
+  cgraph_node *origin;
+  /* Points to first nested function, if any.  */
+  cgraph_node *nested;
+  /* Pointer to the next function with same origin, if any.  */
+  cgraph_node *next_nested;
+};
+
+extern void maybe_record_nested_function (cgraph_node *node);
+extern void unnest_function (cgraph_node *node);
+
+/* If there are functions nested in NODE, return first one.  */
+inline cgraph_node *
+first_nested_function (cgraph_node *node)
+{
+  nested_function_info *info = nested_function_info::get (node);
+  return info ? info->nested : NULL;
+}
+
+/* Return next nested function (used to iterate from first_nested_function).  */
+inline cgraph_node *
+next_nested_function (cgraph_node *node)
+{
+  return nested_function_info::get (node)->next_nested;
+}
+
+/* Return origin of nested function (and NULL otherwise).  */
+inline cgraph_node *
+nested_function_origin (cgraph_node *node)
+{
+  nested_function_info *info = nested_function_info::get (node);
+  return info ? info->origin : NULL;
+}
+
 #endif /* GCC_TREE_NESTED_H */