From 227ffed7dbbdffeeb5bc013852d61a97aa468c62 Mon Sep 17 00:00:00 2001 From: Nathan Sidwell Date: Wed, 8 Jun 2022 11:25:14 -0700 Subject: [PATCH] c++: Better module initializer code Every module interface needs to emit a global initializer, but it might have nothing to init. In those cases, there's no need for any idempotency boolean to be emitted. gcc/cp * cp-tree.h (module_initializer_kind): Replace with ... (module_global_init_needed, module_has_import_inits): ... these. * decl2.cc (start_objects): Add has_body parm. Reorganize module initializer creation. (generate_ctor_or_dtor_function): Adjust. (c_parse_final_cleanups): Adjust. (vtv_start_verification_constructor_init_function): Adjust. * module.cc (module_initializer_kind): Replace with ... (module_global_init_needed, module_has_import_inits): ... these. gcc/testsuite/ * g++.dg/modules/init-2_a.C: Check no idempotency. * g++.dg/modules/init-2_b.C: Check idempotency. --- gcc/cp/cp-tree.h | 3 ++- gcc/cp/decl2.cc | 32 +++++++++++++------------ gcc/cp/module.cc | 23 +++++++++--------- gcc/testsuite/g++.dg/modules/init-2_a.C | 2 ++ gcc/testsuite/g++.dg/modules/init-2_b.C | 2 ++ 5 files changed, 34 insertions(+), 28 deletions(-) diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 3d8a08b8dd7..a5d93282167 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -7179,7 +7179,8 @@ extern module_state *get_module (tree name, module_state *parent = NULL, bool partition = false); extern bool module_may_redeclare (tree decl); -extern int module_initializer_kind (); +extern bool module_global_init_needed (); +extern bool module_has_import_inits (); extern void module_add_import_initializers (); /* Where the namespace-scope decl was originally declared. */ diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc index bfb6a32e3b6..9de9a7a4f8a 100644 --- a/gcc/cp/decl2.cc +++ b/gcc/cp/decl2.cc @@ -55,7 +55,7 @@ int raw_dump_id; extern cpp_reader *parse_in; -static tree start_objects (bool, unsigned); +static tree start_objects (bool, unsigned, bool); static tree finish_objects (bool, unsigned, tree); static tree start_partial_init_fini_fn (bool, unsigned, unsigned); static void finish_partial_init_fini_fn (tree); @@ -3848,15 +3848,13 @@ generate_tls_wrapper (tree fn) /* Start a global constructor or destructor function. */ static tree -start_objects (bool initp, unsigned priority) +start_objects (bool initp, unsigned priority, bool has_body) { - int module_init = 0; - - if (priority == DEFAULT_INIT_PRIORITY && initp) - module_init = module_initializer_kind (); - + bool default_init = initp && priority == DEFAULT_INIT_PRIORITY; + bool is_module_init = default_init && module_global_init_needed (); tree name = NULL_TREE; - if (module_init > 0) + + if (is_module_init) name = mangle_module_global_init (0); else { @@ -3880,7 +3878,7 @@ start_objects (bool initp, unsigned priority) tree fntype = build_function_type (void_type_node, void_list_node); tree fndecl = build_lang_decl (FUNCTION_DECL, name, fntype); DECL_CONTEXT (fndecl) = FROB_CONTEXT (global_namespace); - if (module_init > 0) + if (is_module_init) { SET_DECL_ASSEMBLER_NAME (fndecl, name); TREE_PUBLIC (fndecl) = true; @@ -3905,8 +3903,10 @@ start_objects (bool initp, unsigned priority) tree body = begin_compound_stmt (BCS_FN_BODY); - if (module_init > 0) + bool has_import_inits = default_init && module_has_import_inits (); + if (is_module_init && (has_import_inits || has_body)) { + // If the function is going to be empty, don't emit idempotency. // 'static bool __in_chrg = false; // if (__inchrg) return; // __inchrg = true @@ -3930,7 +3930,7 @@ start_objects (bool initp, unsigned priority) finish_expr_stmt (assign); } - if (module_init) + if (has_import_inits) module_add_import_initializers (); return body; @@ -4321,7 +4321,7 @@ generate_ctor_or_dtor_function (bool initp, unsigned priority, { input_location = locus; - tree body = start_objects (initp, priority); + tree body = start_objects (initp, priority, bool (fns)); /* To make sure dynamic construction doesn't access globals from other compilation units where they might not be yet constructed, for @@ -4359,7 +4359,9 @@ generate_ctor_or_dtor_function (bool initp, unsigned priority, if (initp && (flag_sanitize & SANITIZE_ADDRESS)) finish_expr_stmt (asan_dynamic_init_call (/*after_p=*/true)); - /* Close out the function. */ + /* Close out the function, and arrange for it to be called at init + or fini time. (Even module initializer functions need this, as + we cannot guarantee the module is imported somewhere in the programq.) */ expand_or_defer_fn (finish_objects (initp, priority, body)); } @@ -5205,7 +5207,7 @@ c_parse_final_cleanups (void) push_lang_context (lang_name_c); if ((c_dialect_objc () && objc_static_init_needed_p ()) - || module_initializer_kind ()) + || module_global_init_needed () || module_has_import_inits ()) { // Make sure there's a default priority entry. if (!static_init_fini_fns[true]) @@ -5871,7 +5873,7 @@ mark_used (tree decl) tree vtv_start_verification_constructor_init_function (void) { - return start_objects (/*initp=*/true, MAX_RESERVED_INIT_PRIORITY - 1); + return start_objects (/*initp=*/true, MAX_RESERVED_INIT_PRIORITY - 1, true); } tree diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc index d1dc73724d1..7e36996c0fc 100644 --- a/gcc/cp/module.cc +++ b/gcc/cp/module.cc @@ -19026,22 +19026,21 @@ declare_module (module_state *module, location_t from_loc, bool exporting_p, } } -/* +1, we're the primary or a partition. Therefore emitting a - globally-callable idemportent initializer function. - -1, we have direct imports. Therefore emitting calls to their - initializers. */ +/* Return true IFF we must emit a module global initializer function + (which will be called by importers' init code). */ -int -module_initializer_kind () +bool +module_global_init_needed () { - int result = 0; + return module_has_cmi_p () && !header_module_p (); +} - if (module_has_cmi_p () && !header_module_p ()) - result = +1; - else if (num_init_calls_needed) - result = -1; +/* Return true IFF we have import global inits to call. */ - return result; +bool +module_has_import_inits () +{ + return bool (num_init_calls_needed); } /* Emit calls to each direct import's global initializer. Including diff --git a/gcc/testsuite/g++.dg/modules/init-2_a.C b/gcc/testsuite/g++.dg/modules/init-2_a.C index c0390a1b56e..4174cf53911 100644 --- a/gcc/testsuite/g++.dg/modules/init-2_a.C +++ b/gcc/testsuite/g++.dg/modules/init-2_a.C @@ -3,3 +3,5 @@ export module Foo; // { dg-module-cmi Foo } // { dg-final { scan-assembler {_ZGIW3Foo:} } } +// But it is empty, and so no idempotency bool +// { dg-final { scan-assembler-not {_ZZ9_ZGIW3FooE9__in_chrg} } } diff --git a/gcc/testsuite/g++.dg/modules/init-2_b.C b/gcc/testsuite/g++.dg/modules/init-2_b.C index 912ee406931..4350944139f 100644 --- a/gcc/testsuite/g++.dg/modules/init-2_b.C +++ b/gcc/testsuite/g++.dg/modules/init-2_b.C @@ -5,4 +5,6 @@ export module Bar; import Foo; // { dg-final { scan-assembler {_?_ZGIW3Bar:} } } +// There should be an idempotency check +// { dg-final { scan-assembler {_ZZ9_ZGIW3BarE9__in_chrg} } } // { dg-final { scan-assembler {call[ \t]+_?_ZGIW3Foo} { target i?86-*-* x86_64-*-* } } } -- 2.30.2