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, 6 insertions, 7 deletions

diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index 19ae876..05713c2 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -673,9 +673,8 @@ cgraph_node::analyze (void)
       /* Lower the function.  */
       if (!lowered)
 	{
-	  if (nested)
+	  if (first_nested_function (this))
 	    lower_nested_functions (decl);
-	  gcc_assert (!nested);
 
 	  gimple_register_cfg_hooks ();
 	  bitmap_obstack_initialize (NULL);
@@ -2343,14 +2342,11 @@ cgraph_node::expand (void)
     }
 
   gimple_set_body (decl, NULL);
-  if (DECL_STRUCT_FUNCTION (decl) == 0
-      && !cgraph_node::get (decl)->origin)
+  if (DECL_STRUCT_FUNCTION (decl) == 0)
     {
       /* Stop pointing to the local nodes about to be freed.
 	 But DECL_INITIAL must remain nonzero so we know this
-	 was an actual function definition.
-	 For a nested function, this is done in c_pop_function_context.
-	 If rest_of_compilation set this to 0, leave it 0.  */
+	 was an actual function definition.  */
       if (DECL_INITIAL (decl) != 0)
 	DECL_INITIAL (decl) = error_mark_node;
     }
@@ -3001,6 +2997,9 @@ symbol_table::finalize_compilation_unit (void)
   /* Gimplify and lower thunks.  */
   analyze_functions (/*first_time=*/false);
 
+  /* All nested functions should be lowered now.  */
+  nested_function_info::release ();
+
   /* Offloading requires LTO infrastructure.  */
   if (!in_lto_p && g->have_offload)
     flag_generate_offload = 1;