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Diffstat (limited to 'gcc/cp/method.cc')
| -rw-r--r-- | gcc/cp/method.cc | 3506 |
1 files changed, 3506 insertions, 0 deletions
diff --git a/gcc/cp/method.cc b/gcc/cp/method.cc new file mode 100644 index 0000000..fe1147c --- /dev/null +++ b/gcc/cp/method.cc @@ -0,0 +1,3506 @@ +/* Handle the hair of processing (but not expanding) inline functions. + Also manage function and variable name overloading. + Copyright (C) 1987-2022 Free Software Foundation, Inc. + Contributed by Michael Tiemann (tiemann@cygnus.com) + +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/>. */ + + +/* Handle method declarations. */ +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "target.h" +#include "cp-tree.h" +#include "stringpool.h" +#include "cgraph.h" +#include "varasm.h" +#include "toplev.h" +#include "intl.h" +#include "common/common-target.h" + +static void do_build_copy_assign (tree); +static void do_build_copy_constructor (tree); +static tree make_alias_for_thunk (tree); + +/* Called once to initialize method.c. */ + +void +init_method (void) +{ + init_mangle (); +} + +/* Return a this or result adjusting thunk to FUNCTION. THIS_ADJUSTING + indicates whether it is a this or result adjusting thunk. + FIXED_OFFSET and VIRTUAL_OFFSET indicate how to do the adjustment + (see thunk_adjust). VIRTUAL_OFFSET can be NULL, but FIXED_OFFSET + never is. VIRTUAL_OFFSET is the /index/ into the vtable for this + adjusting thunks, we scale it to a byte offset. For covariant + thunks VIRTUAL_OFFSET is the virtual binfo. You must post process + the returned thunk with finish_thunk. */ + +tree +make_thunk (tree function, bool this_adjusting, + tree fixed_offset, tree virtual_offset) +{ + HOST_WIDE_INT d; + tree thunk; + + gcc_assert (TREE_CODE (function) == FUNCTION_DECL); + /* We can have this thunks to covariant thunks, but not vice versa. */ + gcc_assert (!DECL_THIS_THUNK_P (function)); + gcc_assert (!DECL_RESULT_THUNK_P (function) || this_adjusting); + + /* Scale the VIRTUAL_OFFSET to be in terms of bytes. */ + if (this_adjusting && virtual_offset) + virtual_offset + = size_binop (MULT_EXPR, + virtual_offset, + convert (ssizetype, + TYPE_SIZE_UNIT (vtable_entry_type))); + + d = tree_to_shwi (fixed_offset); + + /* See if we already have the thunk in question. For this_adjusting + thunks VIRTUAL_OFFSET will be an INTEGER_CST, for covariant thunks it + will be a BINFO. */ + for (thunk = DECL_THUNKS (function); thunk; thunk = DECL_CHAIN (thunk)) + if (DECL_THIS_THUNK_P (thunk) == this_adjusting + && THUNK_FIXED_OFFSET (thunk) == d + && !virtual_offset == !THUNK_VIRTUAL_OFFSET (thunk) + && (!virtual_offset + || (this_adjusting + ? tree_int_cst_equal (THUNK_VIRTUAL_OFFSET (thunk), + virtual_offset) + : THUNK_VIRTUAL_OFFSET (thunk) == virtual_offset))) + return thunk; + + /* All thunks must be created before FUNCTION is actually emitted; + the ABI requires that all thunks be emitted together with the + function to which they transfer control. */ + gcc_assert (!TREE_ASM_WRITTEN (function)); + /* Likewise, we can only be adding thunks to a function declared in + the class currently being laid out. */ + gcc_assert (TYPE_SIZE (DECL_CONTEXT (function)) + && TYPE_BEING_DEFINED (DECL_CONTEXT (function))); + + thunk = build_decl (DECL_SOURCE_LOCATION (function), + FUNCTION_DECL, NULL_TREE, TREE_TYPE (function)); + DECL_LANG_SPECIFIC (thunk) = DECL_LANG_SPECIFIC (function); + cxx_dup_lang_specific_decl (thunk); + DECL_VIRTUAL_P (thunk) = true; + SET_DECL_THUNKS (thunk, NULL_TREE); + + DECL_CONTEXT (thunk) = DECL_CONTEXT (function); + TREE_READONLY (thunk) = TREE_READONLY (function); + TREE_THIS_VOLATILE (thunk) = TREE_THIS_VOLATILE (function); + TREE_PUBLIC (thunk) = TREE_PUBLIC (function); + SET_DECL_THUNK_P (thunk, this_adjusting); + THUNK_TARGET (thunk) = function; + THUNK_FIXED_OFFSET (thunk) = d; + THUNK_VIRTUAL_OFFSET (thunk) = virtual_offset; + THUNK_ALIAS (thunk) = NULL_TREE; + + DECL_INTERFACE_KNOWN (thunk) = 1; + DECL_NOT_REALLY_EXTERN (thunk) = 1; + DECL_COMDAT (thunk) = DECL_COMDAT (function); + DECL_SAVED_AUTO_RETURN_TYPE (thunk) = NULL; + /* The thunk itself is not a constructor or destructor, even if + the thing it is thunking to is. */ + DECL_CXX_DESTRUCTOR_P (thunk) = 0; + DECL_CXX_CONSTRUCTOR_P (thunk) = 0; + DECL_EXTERNAL (thunk) = 1; + DECL_ARTIFICIAL (thunk) = 1; + /* The THUNK is not a pending inline, even if the FUNCTION is. */ + DECL_PENDING_INLINE_P (thunk) = 0; + DECL_DECLARED_INLINE_P (thunk) = 0; + /* Nor is it a template instantiation. */ + DECL_USE_TEMPLATE (thunk) = 0; + DECL_TEMPLATE_INFO (thunk) = NULL; + + /* Add it to the list of thunks associated with FUNCTION. */ + DECL_CHAIN (thunk) = DECL_THUNKS (function); + SET_DECL_THUNKS (function, thunk); + + return thunk; +} + +/* Finish THUNK, a thunk decl. */ + +void +finish_thunk (tree thunk) +{ + tree function, name; + tree fixed_offset = ssize_int (THUNK_FIXED_OFFSET (thunk)); + tree virtual_offset = THUNK_VIRTUAL_OFFSET (thunk); + + gcc_assert (!DECL_NAME (thunk) && DECL_THUNK_P (thunk)); + if (virtual_offset && DECL_RESULT_THUNK_P (thunk)) + virtual_offset = BINFO_VPTR_FIELD (virtual_offset); + function = THUNK_TARGET (thunk); + name = mangle_thunk (function, DECL_THIS_THUNK_P (thunk), + fixed_offset, virtual_offset, thunk); + + /* We can end up with declarations of (logically) different + covariant thunks, that do identical adjustments. The two thunks + will be adjusting between within different hierarchies, which + happen to have the same layout. We must nullify one of them to + refer to the other. */ + if (DECL_RESULT_THUNK_P (thunk)) + { + tree cov_probe; + + for (cov_probe = DECL_THUNKS (function); + cov_probe; cov_probe = DECL_CHAIN (cov_probe)) + if (DECL_NAME (cov_probe) == name) + { + gcc_assert (!DECL_THUNKS (thunk)); + THUNK_ALIAS (thunk) = (THUNK_ALIAS (cov_probe) + ? THUNK_ALIAS (cov_probe) : cov_probe); + break; + } + } + + DECL_NAME (thunk) = name; + SET_DECL_ASSEMBLER_NAME (thunk, name); +} + +static GTY (()) int thunk_labelno; + +/* Create a static alias to target. */ + +tree +make_alias_for (tree target, tree newid) +{ + tree alias = build_decl (DECL_SOURCE_LOCATION (target), + TREE_CODE (target), newid, TREE_TYPE (target)); + DECL_LANG_SPECIFIC (alias) = DECL_LANG_SPECIFIC (target); + cxx_dup_lang_specific_decl (alias); + DECL_CONTEXT (alias) = DECL_CONTEXT (target); + TREE_READONLY (alias) = TREE_READONLY (target); + TREE_THIS_VOLATILE (alias) = TREE_THIS_VOLATILE (target); + TREE_PUBLIC (alias) = 0; + DECL_INTERFACE_KNOWN (alias) = 1; + if (DECL_LANG_SPECIFIC (alias)) + { + DECL_NOT_REALLY_EXTERN (alias) = 1; + DECL_USE_TEMPLATE (alias) = 0; + DECL_TEMPLATE_INFO (alias) = NULL; + } + DECL_EXTERNAL (alias) = 0; + DECL_ARTIFICIAL (alias) = 1; + DECL_TEMPLATE_INSTANTIATED (alias) = 0; + if (TREE_CODE (alias) == FUNCTION_DECL) + { + DECL_SAVED_AUTO_RETURN_TYPE (alias) = NULL; + DECL_CXX_DESTRUCTOR_P (alias) = 0; + DECL_CXX_CONSTRUCTOR_P (alias) = 0; + DECL_PENDING_INLINE_P (alias) = 0; + DECL_DECLARED_INLINE_P (alias) = 0; + DECL_INITIAL (alias) = error_mark_node; + DECL_ARGUMENTS (alias) = copy_list (DECL_ARGUMENTS (target)); + } + else + TREE_STATIC (alias) = 1; + TREE_ADDRESSABLE (alias) = 1; + TREE_USED (alias) = 1; + SET_DECL_ASSEMBLER_NAME (alias, DECL_NAME (alias)); + return alias; +} + +static tree +make_alias_for_thunk (tree function) +{ + tree alias; + char buf[256]; + + targetm.asm_out.generate_internal_label (buf, "LTHUNK", thunk_labelno); + thunk_labelno++; + + alias = make_alias_for (function, get_identifier (buf)); + + if (!flag_syntax_only) + { + struct cgraph_node *funcn, *aliasn; + funcn = cgraph_node::get (function); + gcc_checking_assert (funcn); + aliasn = cgraph_node::create_same_body_alias (alias, function); + DECL_ASSEMBLER_NAME (function); + gcc_assert (aliasn != NULL); + } + + return alias; +} + +/* Emit the definition of a C++ multiple inheritance or covariant + return vtable thunk. If EMIT_P is nonzero, the thunk is emitted + immediately. */ + +void +use_thunk (tree thunk_fndecl, bool emit_p) +{ + tree a, t, function, alias; + tree virtual_offset; + HOST_WIDE_INT fixed_offset, virtual_value; + bool this_adjusting = DECL_THIS_THUNK_P (thunk_fndecl); + struct cgraph_node *funcn, *thunk_node; + + /* We should have called finish_thunk to give it a name. */ + gcc_assert (DECL_NAME (thunk_fndecl)); + + /* We should never be using an alias, always refer to the + aliased thunk. */ + gcc_assert (!THUNK_ALIAS (thunk_fndecl)); + + if (TREE_ASM_WRITTEN (thunk_fndecl)) + return; + + function = THUNK_TARGET (thunk_fndecl); + if (DECL_RESULT (thunk_fndecl)) + /* We already turned this thunk into an ordinary function. + There's no need to process this thunk again. */ + return; + + if (DECL_THUNK_P (function)) + /* The target is itself a thunk, process it now. */ + use_thunk (function, emit_p); + + /* Thunks are always addressable; they only appear in vtables. */ + TREE_ADDRESSABLE (thunk_fndecl) = 1; + + /* Figure out what function is being thunked to. It's referenced in + this translation unit. */ + TREE_ADDRESSABLE (function) = 1; + mark_used (function); + if (!emit_p) + return; + + if (TARGET_USE_LOCAL_THUNK_ALIAS_P (function)) + alias = make_alias_for_thunk (function); + else + alias = function; + + fixed_offset = THUNK_FIXED_OFFSET (thunk_fndecl); + virtual_offset = THUNK_VIRTUAL_OFFSET (thunk_fndecl); + + if (virtual_offset) + { + if (!this_adjusting) + virtual_offset = BINFO_VPTR_FIELD (virtual_offset); + virtual_value = tree_to_shwi (virtual_offset); + gcc_assert (virtual_value); + } + else + virtual_value = 0; + + /* And, if we need to emit the thunk, it's used. */ + mark_used (thunk_fndecl); + /* This thunk is actually defined. */ + DECL_EXTERNAL (thunk_fndecl) = 0; + /* The linkage of the function may have changed. FIXME in linkage + rewrite. */ + gcc_assert (DECL_INTERFACE_KNOWN (function)); + TREE_PUBLIC (thunk_fndecl) = TREE_PUBLIC (function); + DECL_VISIBILITY (thunk_fndecl) = DECL_VISIBILITY (function); + DECL_VISIBILITY_SPECIFIED (thunk_fndecl) + = DECL_VISIBILITY_SPECIFIED (function); + DECL_COMDAT (thunk_fndecl) = DECL_COMDAT (function); + DECL_WEAK (thunk_fndecl) = DECL_WEAK (function); + + if (flag_syntax_only) + { + TREE_ASM_WRITTEN (thunk_fndecl) = 1; + return; + } + + push_to_top_level (); + + if (TARGET_USE_LOCAL_THUNK_ALIAS_P (function) + && targetm_common.have_named_sections) + { + tree fn = function; + struct symtab_node *symbol; + + if ((symbol = symtab_node::get (function)) + && symbol->alias) + { + if (symbol->analyzed) + fn = symtab_node::get (function)->ultimate_alias_target ()->decl; + else + fn = symtab_node::get (function)->alias_target; + } + resolve_unique_section (fn, 0, flag_function_sections); + + if (DECL_SECTION_NAME (fn) != NULL && DECL_ONE_ONLY (fn)) + { + resolve_unique_section (thunk_fndecl, 0, flag_function_sections); + + /* Output the thunk into the same section as function. */ + set_decl_section_name (thunk_fndecl, fn); + symtab_node::get (thunk_fndecl)->implicit_section + = symtab_node::get (fn)->implicit_section; + } + } + + /* Set up cloned argument trees for the thunk. */ + t = NULL_TREE; + for (a = DECL_ARGUMENTS (function); a; a = DECL_CHAIN (a)) + { + tree x = copy_node (a); + DECL_CHAIN (x) = t; + DECL_CONTEXT (x) = thunk_fndecl; + SET_DECL_RTL (x, NULL); + DECL_HAS_VALUE_EXPR_P (x) = 0; + TREE_ADDRESSABLE (x) = 0; + t = x; + } + a = nreverse (t); + DECL_ARGUMENTS (thunk_fndecl) = a; + TREE_ASM_WRITTEN (thunk_fndecl) = 1; + funcn = cgraph_node::get (function); + gcc_checking_assert (funcn); + thunk_node = funcn->create_thunk (thunk_fndecl, function, + this_adjusting, fixed_offset, virtual_value, + 0, virtual_offset, alias); + if (DECL_ONE_ONLY (function)) + thunk_node->add_to_same_comdat_group (funcn); + + pop_from_top_level (); +} + +/* Code for synthesizing methods which have default semantics defined. */ + +/* True iff CTYPE has a trivial SFK. */ + +static bool +type_has_trivial_fn (tree ctype, special_function_kind sfk) +{ + switch (sfk) + { + case sfk_constructor: + return !TYPE_HAS_COMPLEX_DFLT (ctype); + case sfk_copy_constructor: + return !TYPE_HAS_COMPLEX_COPY_CTOR (ctype); + case sfk_move_constructor: + return !TYPE_HAS_COMPLEX_MOVE_CTOR (ctype); + case sfk_copy_assignment: + return !TYPE_HAS_COMPLEX_COPY_ASSIGN (ctype); + case sfk_move_assignment: + return !TYPE_HAS_COMPLEX_MOVE_ASSIGN (ctype); + case sfk_destructor: + case sfk_virtual_destructor: + return !TYPE_HAS_NONTRIVIAL_DESTRUCTOR (ctype); + case sfk_inheriting_constructor: + case sfk_comparison: + return false; + default: + gcc_unreachable (); + } +} + +/* Note that CTYPE has a non-trivial SFK even though we previously thought + it was trivial. */ + +static void +type_set_nontrivial_flag (tree ctype, special_function_kind sfk) +{ + switch (sfk) + { + case sfk_constructor: + TYPE_HAS_COMPLEX_DFLT (ctype) = true; + return; + case sfk_copy_constructor: + TYPE_HAS_COMPLEX_COPY_CTOR (ctype) = true; + return; + case sfk_move_constructor: + TYPE_HAS_COMPLEX_MOVE_CTOR (ctype) = true; + return; + case sfk_copy_assignment: + TYPE_HAS_COMPLEX_COPY_ASSIGN (ctype) = true; + return; + case sfk_move_assignment: + TYPE_HAS_COMPLEX_MOVE_ASSIGN (ctype) = true; + return; + case sfk_destructor: + TYPE_HAS_NONTRIVIAL_DESTRUCTOR (ctype) = true; + return; + case sfk_inheriting_constructor: + default: + gcc_unreachable (); + } +} + +/* True iff FN is a trivial defaulted member function ([cd]tor, op=). */ + +bool +trivial_fn_p (tree fn) +{ + if (TREE_CODE (fn) == TEMPLATE_DECL) + return false; + if (!DECL_DEFAULTED_FN (fn)) + return false; + + /* If fn is a clone, get the primary variant. */ + if (tree prim = DECL_CLONED_FUNCTION (fn)) + fn = prim; + return type_has_trivial_fn (DECL_CONTEXT (fn), special_function_p (fn)); +} + +/* PARM is a PARM_DECL for a function which we want to forward to another + function without changing its value category, a la std::forward. */ + +tree +forward_parm (tree parm) +{ + tree exp = convert_from_reference (parm); + tree type = TREE_TYPE (parm); + if (DECL_PACK_P (parm)) + type = PACK_EXPANSION_PATTERN (type); + if (!TYPE_REF_P (type)) + type = cp_build_reference_type (type, /*rval=*/true); + warning_sentinel w (warn_useless_cast); + exp = build_static_cast (input_location, type, exp, + tf_warning_or_error); + if (DECL_PACK_P (parm)) + exp = make_pack_expansion (exp); + return exp; +} + +/* Strip all inheriting constructors, if any, to return the original + constructor from a (possibly indirect) base class. */ + +tree +strip_inheriting_ctors (tree dfn) +{ + if (!flag_new_inheriting_ctors) + return dfn; + tree fn = dfn; + while (tree inh = DECL_INHERITED_CTOR (fn)) + fn = OVL_FIRST (inh); + + if (TREE_CODE (fn) == TEMPLATE_DECL + && TREE_CODE (dfn) == FUNCTION_DECL) + fn = DECL_TEMPLATE_RESULT (fn); + return fn; +} + +/* Find the binfo for the base subobject of BINFO being initialized by + inherited constructor FNDECL (a member of a direct base of BINFO). */ + +static tree inherited_ctor_binfo (tree, tree); +static tree +inherited_ctor_binfo_1 (tree binfo, tree fndecl) +{ + tree base = DECL_CONTEXT (fndecl); + tree base_binfo; + for (int i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) + if (BINFO_TYPE (base_binfo) == base) + return inherited_ctor_binfo (base_binfo, fndecl); + + gcc_unreachable(); +} + +/* Find the binfo for the base subobject of BINFO being initialized by + inheriting constructor FNDECL (a member of BINFO), or BINFO if FNDECL is not + an inheriting constructor. */ + +static tree +inherited_ctor_binfo (tree binfo, tree fndecl) +{ + tree inh = DECL_INHERITED_CTOR (fndecl); + if (!inh) + return binfo; + + tree results = NULL_TREE; + for (ovl_iterator iter (inh); iter; ++iter) + { + tree one = inherited_ctor_binfo_1 (binfo, *iter); + if (!results) + results = one; + else if (one != results) + results = tree_cons (NULL_TREE, one, results); + } + return results; +} + +/* Find the binfo for the base subobject being initialized by inheriting + constructor FNDECL, or NULL_TREE if FNDECL is not an inheriting + constructor. */ + +tree +inherited_ctor_binfo (tree fndecl) +{ + if (!DECL_INHERITED_CTOR (fndecl)) + return NULL_TREE; + tree binfo = TYPE_BINFO (DECL_CONTEXT (fndecl)); + return inherited_ctor_binfo (binfo, fndecl); +} + + +/* True if we should omit all user-declared parameters from a base + construtor built from complete constructor FN. + That's when the ctor is inherited from a virtual base. */ + +bool +base_ctor_omit_inherited_parms (tree comp_ctor) +{ + gcc_checking_assert (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (comp_ctor)); + + if (!flag_new_inheriting_ctors) + /* We only optimize away the parameters in the new model. */ + return false; + + if (!CLASSTYPE_VBASECLASSES (DECL_CONTEXT (comp_ctor))) + return false; + + if (FUNCTION_FIRST_USER_PARMTYPE (comp_ctor) == void_list_node) + /* No user-declared parameters to omit. */ + return false; + + for (tree binfo = inherited_ctor_binfo (comp_ctor); + binfo; + binfo = BINFO_INHERITANCE_CHAIN (binfo)) + if (BINFO_VIRTUAL_P (binfo)) + return true; + + return false; +} + + +/* True if we should omit all user-declared parameters from constructor FN, + because it is a base clone of a ctor inherited from a virtual base. */ + +bool +ctor_omit_inherited_parms (tree fn) +{ + gcc_checking_assert (TREE_CODE (fn) == FUNCTION_DECL); + + if (!DECL_BASE_CONSTRUCTOR_P (fn)) + return false; + + return base_ctor_omit_inherited_parms (DECL_CLONED_FUNCTION (fn)); +} + +/* True iff constructor(s) INH inherited into BINFO initializes INIT_BINFO. + This can be true for multiple virtual bases as well as one direct + non-virtual base. */ + +static bool +binfo_inherited_from (tree binfo, tree init_binfo, tree inh) +{ + /* inh is an OVERLOAD if we inherited the same constructor along + multiple paths, check all of them. */ + for (ovl_iterator iter (inh); iter; ++iter) + { + tree fn = *iter; + tree base = DECL_CONTEXT (fn); + tree base_binfo = NULL_TREE; + for (int i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) + if (BINFO_TYPE (base_binfo) == base) + break; + if (base_binfo == init_binfo + || (flag_new_inheriting_ctors + && binfo_inherited_from (base_binfo, init_binfo, + DECL_INHERITED_CTOR (fn)))) + return true; + } + return false; +} + +/* Subroutine of do_build_copy_constructor: Add a mem-initializer for BINFO + given the parameter or parameters PARM, possibly inherited constructor + base INH, or move flag MOVE_P. */ + +static tree +add_one_base_init (tree binfo, tree parm, bool move_p, tree inh, + tree member_init_list) +{ + tree init; + if (inh) + { + /* An inheriting constructor only has a mem-initializer for + the base it inherits from. */ + if (!binfo_inherited_from (TYPE_BINFO (current_class_type), binfo, inh)) + return member_init_list; + + tree *p = &init; + init = NULL_TREE; + for (; parm; parm = DECL_CHAIN (parm)) + { + tree exp = forward_parm (parm); + *p = build_tree_list (NULL_TREE, exp); + p = &TREE_CHAIN (*p); + } + } + else + { + init = build_base_path (PLUS_EXPR, parm, binfo, 1, + tf_warning_or_error); + if (move_p) + init = move (init); + init = build_tree_list (NULL_TREE, init); + } + return tree_cons (binfo, init, member_init_list); +} + +/* Generate code for default X(X&) or X(X&&) constructor or an inheriting + constructor. */ + +static void +do_build_copy_constructor (tree fndecl) +{ + tree parm = FUNCTION_FIRST_USER_PARM (fndecl); + bool move_p = DECL_MOVE_CONSTRUCTOR_P (fndecl); + bool trivial = trivial_fn_p (fndecl); + tree inh = DECL_INHERITED_CTOR (fndecl); + + if (!inh) + parm = convert_from_reference (parm); + + if (trivial) + { + if (is_empty_class (current_class_type)) + /* Don't copy the padding byte; it might not have been allocated + if *this is a base subobject. */; + else if (tree_int_cst_equal (TYPE_SIZE (current_class_type), + CLASSTYPE_SIZE (current_class_type))) + { + tree t = build2 (INIT_EXPR, void_type_node, current_class_ref, parm); + finish_expr_stmt (t); + } + else + { + /* We must only copy the non-tail padding parts. */ + tree base_size = CLASSTYPE_SIZE_UNIT (current_class_type); + base_size = size_binop (MINUS_EXPR, base_size, size_int (1)); + tree array_type = build_array_type (unsigned_char_type_node, + build_index_type (base_size)); + tree alias_set = build_int_cst (TREE_TYPE (current_class_ptr), 0); + tree lhs = build2 (MEM_REF, array_type, + current_class_ptr, alias_set); + tree rhs = build2 (MEM_REF, array_type, + TREE_OPERAND (parm, 0), alias_set); + tree t = build2 (INIT_EXPR, void_type_node, lhs, rhs); + finish_expr_stmt (t); + } + } + else + { + tree member_init_list = NULL_TREE; + int i; + tree binfo, base_binfo; + vec<tree, va_gc> *vbases; + + /* Initialize all the base-classes with the parameter converted + to their type so that we get their copy constructor and not + another constructor that takes current_class_type. We must + deal with the binfo's directly as a direct base might be + inaccessible due to ambiguity. */ + for (vbases = CLASSTYPE_VBASECLASSES (current_class_type), i = 0; + vec_safe_iterate (vbases, i, &binfo); i++) + { + member_init_list = add_one_base_init (binfo, parm, move_p, inh, + member_init_list); + } + + for (binfo = TYPE_BINFO (current_class_type), i = 0; + BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) + { + if (BINFO_VIRTUAL_P (base_binfo)) + continue; + member_init_list = add_one_base_init (base_binfo, parm, move_p, + inh, member_init_list); + } + + if (!inh) + { + int cvquals = cp_type_quals (TREE_TYPE (parm)); + + for (tree fields = TYPE_FIELDS (current_class_type); + fields; fields = DECL_CHAIN (fields)) + { + tree field = fields; + tree expr_type; + + if (TREE_CODE (field) != FIELD_DECL) + continue; + + expr_type = TREE_TYPE (field); + if (DECL_NAME (field)) + { + if (VFIELD_NAME_P (DECL_NAME (field))) + continue; + } + else if (ANON_AGGR_TYPE_P (expr_type) && TYPE_FIELDS (expr_type)) + /* Just use the field; anonymous types can't have + nontrivial copy ctors or assignment ops or this + function would be deleted. */; + else + continue; + + /* Compute the type of "init->field". If the copy-constructor + parameter is, for example, "const S&", and the type of + the field is "T", then the type will usually be "const + T". (There are no cv-qualified variants of reference + types.) */ + if (!TYPE_REF_P (expr_type)) + { + int quals = cvquals; + + if (DECL_MUTABLE_P (field)) + quals &= ~TYPE_QUAL_CONST; + quals |= cp_type_quals (expr_type); + expr_type = cp_build_qualified_type (expr_type, quals); + } + + tree init = build3 (COMPONENT_REF, expr_type, parm, field, NULL_TREE); + if (move_p && !TYPE_REF_P (expr_type) + /* 'move' breaks bit-fields, and has no effect for scalars. */ + && !scalarish_type_p (expr_type)) + init = move (init); + init = build_tree_list (NULL_TREE, init); + + member_init_list = tree_cons (field, init, member_init_list); + } + } + + finish_mem_initializers (member_init_list); + } +} + +static void +do_build_copy_assign (tree fndecl) +{ + tree parm = DECL_CHAIN (DECL_ARGUMENTS (fndecl)); + tree compound_stmt; + bool move_p = move_fn_p (fndecl); + bool trivial = trivial_fn_p (fndecl); + int flags = LOOKUP_NORMAL | LOOKUP_NONVIRTUAL | LOOKUP_DEFAULTED; + + compound_stmt = begin_compound_stmt (0); + parm = convert_from_reference (parm); + + if (trivial + && is_empty_class (current_class_type)) + /* Don't copy the padding byte; it might not have been allocated + if *this is a base subobject. */; + else if (trivial) + { + tree t = build2 (MODIFY_EXPR, void_type_node, current_class_ref, parm); + finish_expr_stmt (t); + } + else + { + tree fields; + int cvquals = cp_type_quals (TREE_TYPE (parm)); + int i; + tree binfo, base_binfo; + + /* Assign to each of the direct base classes. */ + for (binfo = TYPE_BINFO (current_class_type), i = 0; + BINFO_BASE_ITERATE (binfo, i, base_binfo); i++) + { + tree converted_parm; + + /* We must convert PARM directly to the base class + explicitly since the base class may be ambiguous. */ + converted_parm = build_base_path (PLUS_EXPR, parm, base_binfo, 1, + tf_warning_or_error); + if (move_p) + converted_parm = move (converted_parm); + /* Call the base class assignment operator. */ + releasing_vec parmvec (make_tree_vector_single (converted_parm)); + finish_expr_stmt + (build_special_member_call (current_class_ref, + assign_op_identifier, + &parmvec, + base_binfo, + flags, + tf_warning_or_error)); + } + + /* Assign to each of the non-static data members. */ + for (fields = TYPE_FIELDS (current_class_type); + fields; + fields = DECL_CHAIN (fields)) + { + tree comp = current_class_ref; + tree init = parm; + tree field = fields; + tree expr_type; + int quals; + + if (TREE_CODE (field) != FIELD_DECL || DECL_ARTIFICIAL (field)) + continue; + + expr_type = TREE_TYPE (field); + + if (CP_TYPE_CONST_P (expr_type)) + { + error ("non-static const member %q#D, cannot use default " + "assignment operator", field); + continue; + } + else if (TYPE_REF_P (expr_type)) + { + error ("non-static reference member %q#D, cannot use " + "default assignment operator", field); + continue; + } + + if (DECL_NAME (field)) + { + if (VFIELD_NAME_P (DECL_NAME (field))) + continue; + } + else if (ANON_AGGR_TYPE_P (expr_type) + && TYPE_FIELDS (expr_type) != NULL_TREE) + /* Just use the field; anonymous types can't have + nontrivial copy ctors or assignment ops or this + function would be deleted. */; + else + continue; + + comp = build3 (COMPONENT_REF, expr_type, comp, field, NULL_TREE); + + /* Compute the type of init->field */ + quals = cvquals; + if (DECL_MUTABLE_P (field)) + quals &= ~TYPE_QUAL_CONST; + expr_type = cp_build_qualified_type (expr_type, quals); + + init = build3 (COMPONENT_REF, expr_type, init, field, NULL_TREE); + if (move_p && !TYPE_REF_P (expr_type) + /* 'move' breaks bit-fields, and has no effect for scalars. */ + && !scalarish_type_p (expr_type)) + init = move (init); + + if (DECL_NAME (field)) + init = cp_build_modify_expr (input_location, comp, NOP_EXPR, init, + tf_warning_or_error); + else + init = build2 (MODIFY_EXPR, TREE_TYPE (comp), comp, init); + finish_expr_stmt (init); + } + } + finish_return_stmt (current_class_ref); + finish_compound_stmt (compound_stmt); +} + +/* C++20 <compare> comparison category types. */ + +enum comp_cat_tag +{ + cc_partial_ordering, + cc_weak_ordering, + cc_strong_ordering, + cc_last +}; + +/* Names of the comparison categories and their value members, to be indexed by + comp_cat_tag enumerators. genericize_spaceship below relies on the ordering + of the members. */ + +struct comp_cat_info_t +{ + const char *name; + const char *members[4]; +}; +static const comp_cat_info_t comp_cat_info[cc_last] += { + { "partial_ordering", { "equivalent", "greater", "less", "unordered" } }, + { "weak_ordering", { "equivalent", "greater", "less" } }, + { "strong_ordering", { "equal", "greater", "less" } } +}; + +/* A cache of the category types to speed repeated lookups. */ + +static GTY((deletable)) tree comp_cat_cache[cc_last]; + +/* Look up one of the result variables in the comparison category type. */ + +static tree +lookup_comparison_result (tree type, const char *name_str, + tsubst_flags_t complain = tf_warning_or_error) +{ + tree name = get_identifier (name_str); + tree decl = lookup_qualified_name (type, name); + if (TREE_CODE (decl) != VAR_DECL) + { + if (complain & tf_error) + { + auto_diagnostic_group d; + if (decl == error_mark_node || TREE_CODE (decl) == TREE_LIST) + qualified_name_lookup_error (type, name, decl, input_location); + else + error ("%qD is not a static data member", decl); + inform (input_location, "determining value of %qs", "operator<=>"); + } + return error_mark_node; + } + return decl; +} + +/* Look up a <compare> comparison category type in std. */ + +static tree +lookup_comparison_category (comp_cat_tag tag, + tsubst_flags_t complain = tf_warning_or_error) +{ + if (tree cached = comp_cat_cache[tag]) + return cached; + + tree name = get_identifier (comp_cat_info[tag].name); + tree decl = lookup_qualified_name (std_node, name); + if (TREE_CODE (decl) != TYPE_DECL) + { + if (complain & tf_error) + { + auto_diagnostic_group d; + if (decl == error_mark_node || TREE_CODE (decl) == TREE_LIST) + qualified_name_lookup_error (std_node, name, decl, input_location); + else + error ("%qD is not a type", decl); + inform (input_location, "forming type of %qs", "operator<=>"); + } + return error_mark_node; + } + /* Also make sure we can look up the value members now, since we won't + really use them until genericize time. */ + tree type = TREE_TYPE (decl); + for (int i = 0; i < 4; ++i) + { + const char *p = comp_cat_info[tag].members[i]; + if (!p) break; + if (lookup_comparison_result (type, p, complain) + == error_mark_node) + return error_mark_node; + } + return comp_cat_cache[tag] = type; +} + +/* Wrapper that takes the tag rather than the type. */ + +static tree +lookup_comparison_result (comp_cat_tag tag, const char *name_str, + tsubst_flags_t complain = tf_warning_or_error) +{ + tree type = lookup_comparison_category (tag, complain); + return lookup_comparison_result (type, name_str, complain); +} + +/* Wrapper that takes the index into the members array instead of the name. */ + +static tree +lookup_comparison_result (comp_cat_tag tag, tree type, int idx) +{ + const char *name_str = comp_cat_info[tag].members[idx]; + if (!name_str) + return NULL_TREE; + return lookup_comparison_result (type, name_str); +} + +/* Does TYPE correspond to TAG? */ + +static bool +is_cat (tree type, comp_cat_tag tag) +{ + tree name = TYPE_LINKAGE_IDENTIFIER (type); + return id_equal (name, comp_cat_info[tag].name); +} + +/* Return the comp_cat_tag for TYPE. */ + +static comp_cat_tag +cat_tag_for (tree type) +{ + if (!CLASS_TYPE_P (type) || !decl_in_std_namespace_p (TYPE_MAIN_DECL (type))) + return cc_last; + for (int i = 0; i < cc_last; ++i) + { + comp_cat_tag tag = (comp_cat_tag)i; + if (is_cat (type, tag)) + return tag; + } + return cc_last; +} + +/* Return the comparison category tag of a <=> expression with non-class type + OPTYPE. */ + +static comp_cat_tag +spaceship_comp_cat (tree optype) +{ + if (INTEGRAL_OR_ENUMERATION_TYPE_P (optype) || TYPE_PTROBV_P (optype)) + return cc_strong_ordering; + else if (TREE_CODE (optype) == REAL_TYPE) + return cc_partial_ordering; + + /* ??? should vector <=> produce a vector of one of the above? */ + gcc_unreachable (); +} + +/* Return the comparison category type of a <=> expression with non-class type + OPTYPE. */ + +tree +spaceship_type (tree optype, tsubst_flags_t complain) +{ + comp_cat_tag tag = spaceship_comp_cat (optype); + return lookup_comparison_category (tag, complain); +} + +/* Turn <=> with type TYPE and operands OP0 and OP1 into GENERIC. + This is also used by build_comparison_op for fallback to op< and op== + in a defaulted op<=>. */ + +tree +genericize_spaceship (location_t loc, tree type, tree op0, tree op1) +{ + /* ??? maybe optimize based on knowledge of representation? */ + comp_cat_tag tag = cat_tag_for (type); + + if (tag == cc_last && is_auto (type)) + { + /* build_comparison_op is checking to see if we want to suggest changing + the op<=> return type from auto to a specific comparison category; any + category will do for now. */ + tag = cc_strong_ordering; + type = lookup_comparison_category (tag, tf_none); + if (type == error_mark_node) + return error_mark_node; + } + + gcc_checking_assert (tag < cc_last); + + tree r; + bool scalar = SCALAR_TYPE_P (TREE_TYPE (op0)); + if (scalar) + { + op0 = save_expr (op0); + op1 = save_expr (op1); + } + + tree gt = lookup_comparison_result (tag, type, 1); + + int flags = LOOKUP_NORMAL; + tsubst_flags_t complain = tf_none; + tree comp; + + if (tag == cc_partial_ordering) + { + /* op0 == op1 ? equivalent : op0 < op1 ? less : + op1 < op0 ? greater : unordered */ + tree uo = lookup_comparison_result (tag, type, 3); + if (scalar) + { + /* For scalars use the low level operations; using build_new_op causes + trouble with constexpr eval in the middle of genericize (100367). */ + comp = fold_build2 (LT_EXPR, boolean_type_node, op1, op0); + r = fold_build3 (COND_EXPR, type, comp, gt, uo); + } + else + { + comp = build_new_op (loc, LT_EXPR, flags, op1, op0, complain); + r = build_conditional_expr (loc, comp, gt, uo, complain); + } + } + else + /* op0 == op1 ? equal : op0 < op1 ? less : greater */ + r = gt; + + tree lt = lookup_comparison_result (tag, type, 2); + if (scalar) + { + comp = fold_build2 (LT_EXPR, boolean_type_node, op0, op1); + r = fold_build3 (COND_EXPR, type, comp, lt, r); + } + else + { + comp = build_new_op (loc, LT_EXPR, flags, op0, op1, complain); + r = build_conditional_expr (loc, comp, lt, r, complain); + } + + tree eq = lookup_comparison_result (tag, type, 0); + if (scalar) + { + comp = fold_build2 (EQ_EXPR, boolean_type_node, op0, op1); + r = fold_build3 (COND_EXPR, type, comp, eq, r); + } + else + { + comp = build_new_op (loc, EQ_EXPR, flags, op0, op1, complain); + r = build_conditional_expr (loc, comp, eq, r, complain); + } + + return r; +} + +/* Check that the signature of a defaulted comparison operator is + well-formed. */ + +static bool +early_check_defaulted_comparison (tree fn) +{ + location_t loc = DECL_SOURCE_LOCATION (fn); + tree ctx; + if (DECL_CLASS_SCOPE_P (fn)) + ctx = DECL_CONTEXT (fn); + else + ctx = DECL_FRIEND_CONTEXT (fn); + bool ok = true; + + if (cxx_dialect < cxx20) + { + error_at (loc, "defaulted %qD only available with %<-std=c++20%> or " + "%<-std=gnu++20%>", fn); + return false; + } + + if (!DECL_OVERLOADED_OPERATOR_IS (fn, SPACESHIP_EXPR) + && !same_type_p (TREE_TYPE (TREE_TYPE (fn)), boolean_type_node)) + { + diagnostic_t kind = DK_UNSPECIFIED; + int opt = 0; + if (is_auto (TREE_TYPE (fn))) + kind = DK_PEDWARN; + else + kind = DK_ERROR; + emit_diagnostic (kind, loc, opt, + "defaulted %qD must return %<bool%>", fn); + if (kind == DK_ERROR) + ok = false; + } + + bool mem = DECL_NONSTATIC_MEMBER_FUNCTION_P (fn); + if (mem && type_memfn_quals (TREE_TYPE (fn)) != TYPE_QUAL_CONST) + { + error_at (loc, "defaulted %qD must be %<const%>", fn); + ok = false; + } + if (mem && type_memfn_rqual (TREE_TYPE (fn)) == REF_QUAL_RVALUE) + { + error_at (loc, "defaulted %qD must not have %<&&%> ref-qualifier", fn); + ok = false; + } + tree parmnode = FUNCTION_FIRST_USER_PARMTYPE (fn); + bool saw_byval = false; + bool saw_byref = mem; + bool saw_bad = false; + for (; parmnode != void_list_node; parmnode = TREE_CHAIN (parmnode)) + { + tree parmtype = TREE_VALUE (parmnode); + if (CLASS_TYPE_P (parmtype)) + saw_byval = true; + else if (TREE_CODE (parmtype) == REFERENCE_TYPE + && !TYPE_REF_IS_RVALUE (parmtype) + && TYPE_QUALS (TREE_TYPE (parmtype)) == TYPE_QUAL_CONST) + { + saw_byref = true; + parmtype = TREE_TYPE (parmtype); + } + else + saw_bad = true; + + if (!saw_bad && !ctx) + { + /* Defaulted outside the class body. */ + ctx = TYPE_MAIN_VARIANT (parmtype); + if (!is_friend (ctx, fn)) + error_at (loc, "defaulted %qD is not a friend of %qT", fn, ctx); + } + else if (!same_type_ignoring_top_level_qualifiers_p (parmtype, ctx)) + saw_bad = true; + } + + if (saw_bad || (saw_byval && saw_byref)) + { + if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn)) + error_at (loc, "defaulted member %qD must have parameter type " + "%<const %T&%>", fn, ctx); + else if (saw_bad) + error_at (loc, "defaulted %qD must have parameters of either type " + "%<const %T&%> or %qT", fn, ctx, ctx); + else + error_at (loc, "defaulted %qD must have parameters of either type " + "%<const %T&%> or %qT, not both", fn, ctx, ctx); + ok = false; + } + + /* We still need to deduce deleted/constexpr/noexcept and maybe return. */ + DECL_MAYBE_DELETED (fn) = ok; + + return ok; +} + +/* Subroutine of build_comparison_op. Given the vec of memberwise + comparisons COMPS, calculate the overall comparison category for + operator<=>. */ + +static tree +common_comparison_type (vec<tree> &comps) +{ + tree seen[cc_last] = {}; + + for (unsigned i = 0; i < comps.length(); ++i) + { + tree comp = comps[i]; + if (TREE_CODE (comp) == TREE_LIST) + comp = TREE_VALUE (comp); + tree ctype = TREE_TYPE (comp); + comp_cat_tag tag = cat_tag_for (ctype); + /* build_comparison_op already checked this. */ + gcc_checking_assert (tag < cc_last); + seen[tag] = ctype; + } + + /* Otherwise, if at least one T i is std::partial_ordering, U is + std::partial_ordering. */ + if (tree t = seen[cc_partial_ordering]) return t; + + /* Otherwise, if at least one T i is std::weak_ordering, U is + std::weak_ordering. */ + if (tree t = seen[cc_weak_ordering]) return t; + + /* Otherwise, U is std::strong_ordering. */ + if (tree t = seen[cc_strong_ordering]) return t; + return lookup_comparison_category (cc_strong_ordering); +} + +/* Data structure for build_comparison_op. */ + +struct comp_info +{ + tree fndecl; + location_t loc; + tsubst_flags_t complain; + tree_code code; + comp_cat_tag retcat; + bool first_time; + bool constexp; + bool was_constexp; + bool noex; + + comp_info (tree fndecl, tsubst_flags_t complain) + : fndecl (fndecl), complain (complain) + { + loc = DECL_SOURCE_LOCATION (fndecl); + + first_time = DECL_MAYBE_DELETED (fndecl); + DECL_MAYBE_DELETED (fndecl) = false; + + /* Do we want to try to set constexpr? */ + was_constexp = DECL_DECLARED_CONSTEXPR_P (fndecl); + constexp = first_time; + if (constexp) + /* Set this for var_in_constexpr_fn. */ + DECL_DECLARED_CONSTEXPR_P (fndecl) = true; + + /* Do we want to try to set noexcept? */ + noex = first_time; + if (noex) + { + tree raises = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fndecl)); + if (raises && !UNEVALUATED_NOEXCEPT_SPEC_P (raises)) + /* There was an explicit exception-specification. */ + noex = false; + } + } + + /* EXPR is an expression built as part of the function body. + Adjust the properties appropriately. */ + void check (tree expr) + { + if (expr == error_mark_node) + DECL_DELETED_FN (fndecl) = true; + if ((constexp || was_constexp) + && !potential_rvalue_constant_expression (expr)) + { + if (was_constexp) + require_potential_rvalue_constant_expression (expr); + else + constexp = false; + } + if (noex && !expr_noexcept_p (expr, tf_none)) + noex = false; + } + + ~comp_info () + { + if (first_time) + { + DECL_DECLARED_CONSTEXPR_P (fndecl) = constexp || was_constexp; + tree raises = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fndecl)); + if (!raises || UNEVALUATED_NOEXCEPT_SPEC_P (raises)) + { + raises = noex ? noexcept_true_spec : noexcept_false_spec; + TREE_TYPE (fndecl) = build_exception_variant (TREE_TYPE (fndecl), + raises); + } + } + } +}; + +/* Subroutine of build_comparison_op, to compare a single subobject. */ + +static tree +do_one_comp (location_t loc, const comp_info &info, tree sub, tree lhs, tree rhs) +{ + const tree_code code = info.code; + const tree fndecl = info.fndecl; + const comp_cat_tag retcat = info.retcat; + const tsubst_flags_t complain = info.complain; + + tree overload = NULL_TREE; + int flags = LOOKUP_NORMAL | LOOKUP_NONVIRTUAL | LOOKUP_DEFAULTED; + /* If we have an explicit comparison category return type we can fall back + to </=, so don't give an error yet if <=> lookup fails. */ + bool tentative = retcat != cc_last; + tree comp = build_new_op (loc, code, flags, lhs, rhs, + NULL_TREE, NULL_TREE, &overload, + tentative ? tf_none : complain); + + if (code != SPACESHIP_EXPR) + return comp; + + tree rettype = TREE_TYPE (TREE_TYPE (fndecl)); + + if (comp == error_mark_node) + { + if (overload == NULL_TREE && (tentative || complain)) + { + /* No viable <=>, try using op< and op==. */ + tree lteq = genericize_spaceship (loc, rettype, lhs, rhs); + if (lteq != error_mark_node) + { + /* We found usable < and ==. */ + if (retcat != cc_last) + /* Return type is a comparison category, use them. */ + comp = lteq; + else if (complain & tf_error) + /* Return type is auto, suggest changing it. */ + inform (info.loc, "changing the return type from %qs " + "to a comparison category type will allow the " + "comparison to use %qs and %qs", "auto", + "operator<", "operator=="); + } + else if (tentative && complain) + /* No usable < and ==, give an error for op<=>. */ + build_new_op (loc, code, flags, lhs, rhs, complain); + } + if (comp == error_mark_node) + return error_mark_node; + } + + if (FNDECL_USED_AUTO (fndecl) + && cat_tag_for (TREE_TYPE (comp)) == cc_last) + { + /* The operator function is defined as deleted if ... Ri is not a + comparison category type. */ + if (complain & tf_error) + inform (loc, + "three-way comparison of %qD has type %qT, not a " + "comparison category type", sub, TREE_TYPE (comp)); + return error_mark_node; + } + else if (!FNDECL_USED_AUTO (fndecl) + && !can_convert (rettype, TREE_TYPE (comp), complain)) + { + if (complain & tf_error) + error_at (loc, + "three-way comparison of %qD has type %qT, which " + "does not convert to %qT", + sub, TREE_TYPE (comp), rettype); + return error_mark_node; + } + + return comp; +} + +/* Build up the definition of a defaulted comparison operator. Unlike other + defaulted functions that use synthesized_method_walk to determine whether + the function is e.g. deleted, for comparisons we use the same code. We try + to use synthesize_method at the earliest opportunity and bail out if the + function ends up being deleted. */ + +void +build_comparison_op (tree fndecl, bool defining, tsubst_flags_t complain) +{ + comp_info info (fndecl, complain); + + if (!defining && !(complain & tf_error) && !DECL_MAYBE_DELETED (fndecl)) + return; + + int flags = LOOKUP_NORMAL; + const ovl_op_info_t *op = IDENTIFIER_OVL_OP_INFO (DECL_NAME (fndecl)); + tree_code code = info.code = op->tree_code; + + tree lhs = DECL_ARGUMENTS (fndecl); + tree rhs = DECL_CHAIN (lhs); + if (is_this_parameter (lhs)) + lhs = cp_build_fold_indirect_ref (lhs); + else + lhs = convert_from_reference (lhs); + rhs = convert_from_reference (rhs); + tree ctype = TYPE_MAIN_VARIANT (TREE_TYPE (lhs)); + gcc_assert (!defining || COMPLETE_TYPE_P (ctype)); + + iloc_sentinel ils (info.loc); + + /* A defaulted comparison operator function for class C is defined as + deleted if ... C has variant members. */ + if (TREE_CODE (ctype) == UNION_TYPE + && next_initializable_field (TYPE_FIELDS (ctype))) + { + if (complain & tf_error) + inform (info.loc, "cannot default compare union %qT", ctype); + DECL_DELETED_FN (fndecl) = true; + return; + } + + tree compound_stmt = NULL_TREE; + if (defining) + compound_stmt = begin_compound_stmt (0); + else + ++cp_unevaluated_operand; + + tree rettype = TREE_TYPE (TREE_TYPE (fndecl)); + if (code != SPACESHIP_EXPR && is_auto (rettype)) + { + rettype = boolean_type_node; + apply_deduced_return_type (fndecl, rettype); + } + + if (code == EQ_EXPR || code == SPACESHIP_EXPR) + { + comp_cat_tag &retcat = (info.retcat = cc_last); + if (code == SPACESHIP_EXPR && !FNDECL_USED_AUTO (fndecl)) + retcat = cat_tag_for (rettype); + + bool bad = false; + auto_vec<tree> comps; + + /* Compare the base subobjects. We handle them this way, rather than in + the field loop below, because maybe_instantiate_noexcept might bring + us here before we've built the base fields. */ + for (tree base_binfo : BINFO_BASE_BINFOS (TYPE_BINFO (ctype))) + { + tree lhs_base + = build_base_path (PLUS_EXPR, lhs, base_binfo, 0, complain); + tree rhs_base + = build_base_path (PLUS_EXPR, rhs, base_binfo, 0, complain); + + location_t loc = DECL_SOURCE_LOCATION (TYPE_MAIN_DECL (ctype)); + tree comp = do_one_comp (loc, info, BINFO_TYPE (base_binfo), + lhs_base, rhs_base); + if (comp == error_mark_node) + { + bad = true; + continue; + } + + comps.safe_push (comp); + } + + /* Now compare the field subobjects. */ + for (tree field = next_initializable_field (TYPE_FIELDS (ctype)); + field; + field = next_initializable_field (DECL_CHAIN (field))) + { + if (DECL_VIRTUAL_P (field) || DECL_FIELD_IS_BASE (field)) + /* We ignore the vptr, and we already handled bases. */ + continue; + + tree expr_type = TREE_TYPE (field); + + location_t field_loc = DECL_SOURCE_LOCATION (field); + + /* A defaulted comparison operator function for class C is defined as + deleted if any non-static data member of C is of reference type or + C has variant members. */ + if (TREE_CODE (expr_type) == REFERENCE_TYPE) + { + if (complain & tf_error) + inform (field_loc, "cannot default compare " + "reference member %qD", field); + bad = true; + continue; + } + else if (ANON_UNION_TYPE_P (expr_type) + && next_initializable_field (TYPE_FIELDS (expr_type))) + { + if (complain & tf_error) + inform (field_loc, "cannot default compare " + "anonymous union member"); + bad = true; + continue; + } + + tree lhs_mem = build3_loc (field_loc, COMPONENT_REF, expr_type, lhs, + field, NULL_TREE); + tree rhs_mem = build3_loc (field_loc, COMPONENT_REF, expr_type, rhs, + field, NULL_TREE); + tree loop_indexes = NULL_TREE; + while (TREE_CODE (expr_type) == ARRAY_TYPE) + { + /* Flexible array member. */ + if (TYPE_DOMAIN (expr_type) == NULL_TREE + || TYPE_MAX_VALUE (TYPE_DOMAIN (expr_type)) == NULL_TREE) + { + if (complain & tf_error) + inform (field_loc, "cannot default compare " + "flexible array member"); + bad = true; + break; + } + tree maxval = TYPE_MAX_VALUE (TYPE_DOMAIN (expr_type)); + /* [0] array. No subobjects to compare, just skip it. */ + if (integer_all_onesp (maxval)) + break; + tree idx; + /* [1] array, no loop needed, just add [0] ARRAY_REF. + Similarly if !defining. */ + if (integer_zerop (maxval) || !defining) + idx = size_zero_node; + /* Some other array, will need runtime loop. */ + else + { + idx = force_target_expr (sizetype, maxval, complain); + loop_indexes = tree_cons (idx, NULL_TREE, loop_indexes); + } + expr_type = TREE_TYPE (expr_type); + lhs_mem = build4_loc (field_loc, ARRAY_REF, expr_type, lhs_mem, + idx, NULL_TREE, NULL_TREE); + rhs_mem = build4_loc (field_loc, ARRAY_REF, expr_type, rhs_mem, + idx, NULL_TREE, NULL_TREE); + } + if (TREE_CODE (expr_type) == ARRAY_TYPE) + continue; + + tree comp = do_one_comp (field_loc, info, field, lhs_mem, rhs_mem); + if (comp == error_mark_node) + { + bad = true; + continue; + } + + /* Most of the time, comp is the expression that should be evaluated + to compare the two members. If the expression needs to be + evaluated more than once in a loop, it will be a TREE_LIST + instead, whose TREE_VALUE is the expression for one array element, + TREE_PURPOSE is innermost iterator temporary and if the array + is multidimensional, TREE_CHAIN will contain another TREE_LIST + with second innermost iterator in its TREE_PURPOSE and so on. */ + if (loop_indexes) + { + TREE_VALUE (loop_indexes) = comp; + comp = loop_indexes; + } + comps.safe_push (comp); + } + if (code == SPACESHIP_EXPR && is_auto (rettype)) + { + rettype = common_comparison_type (comps); + apply_deduced_return_type (fndecl, rettype); + } + if (bad) + { + DECL_DELETED_FN (fndecl) = true; + goto out; + } + for (unsigned i = 0; i < comps.length(); ++i) + { + tree comp = comps[i]; + tree eq, retval = NULL_TREE, if_ = NULL_TREE; + tree loop_indexes = NULL_TREE; + if (defining) + { + if (TREE_CODE (comp) == TREE_LIST) + { + loop_indexes = comp; + comp = TREE_VALUE (comp); + loop_indexes = nreverse (loop_indexes); + for (tree loop_index = loop_indexes; loop_index; + loop_index = TREE_CHAIN (loop_index)) + { + tree for_stmt = begin_for_stmt (NULL_TREE, NULL_TREE); + tree idx = TREE_PURPOSE (loop_index); + tree maxval = TARGET_EXPR_INITIAL (idx); + TARGET_EXPR_INITIAL (idx) = size_zero_node; + add_stmt (idx); + finish_init_stmt (for_stmt); + finish_for_cond (build2 (LE_EXPR, boolean_type_node, idx, + maxval), for_stmt, false, 0); + finish_for_expr (cp_build_unary_op (PREINCREMENT_EXPR, + TARGET_EXPR_SLOT (idx), + false, complain), + for_stmt); + /* Store in TREE_VALUE the for_stmt tree, so that we can + later on call finish_for_stmt on it (in the reverse + order). */ + TREE_VALUE (loop_index) = for_stmt; + } + loop_indexes = nreverse (loop_indexes); + } + if_ = begin_if_stmt (); + } + /* Spaceship is specified to use !=, but for the comparison category + types, != is equivalent to !(==), so let's use == directly. */ + if (code == EQ_EXPR) + { + /* if (x==y); else return false; */ + eq = comp; + retval = boolean_false_node; + } + else + { + /* if (auto v = x<=>y, v == 0); else return v; */ + if (TREE_CODE (comp) == SPACESHIP_EXPR) + TREE_TYPE (comp) = rettype; + else + comp = build_static_cast (input_location, rettype, comp, + complain); + info.check (comp); + if (defining) + { + tree var = create_temporary_var (rettype); + pushdecl (var); + cp_finish_decl (var, comp, false, NULL_TREE, flags); + comp = retval = var; + } + eq = build_new_op (info.loc, EQ_EXPR, flags, comp, + integer_zero_node, NULL_TREE, NULL_TREE, + NULL, complain); + } + tree ceq = contextual_conv_bool (eq, complain); + info.check (ceq); + if (defining) + { + finish_if_stmt_cond (ceq, if_); + finish_then_clause (if_); + begin_else_clause (if_); + finish_return_stmt (retval); + finish_else_clause (if_); + finish_if_stmt (if_); + for (tree loop_index = loop_indexes; loop_index; + loop_index = TREE_CHAIN (loop_index)) + finish_for_stmt (TREE_VALUE (loop_index)); + } + } + if (defining) + { + tree val; + if (code == EQ_EXPR) + val = boolean_true_node; + else + { + tree seql = lookup_comparison_result (cc_strong_ordering, + "equal", complain); + val = build_static_cast (input_location, rettype, seql, + complain); + } + finish_return_stmt (val); + } + } + else if (code == NE_EXPR) + { + tree comp = build_new_op (info.loc, EQ_EXPR, flags, lhs, rhs, + NULL_TREE, NULL_TREE, NULL, complain); + comp = contextual_conv_bool (comp, complain); + info.check (comp); + if (defining) + { + tree neg = build1 (TRUTH_NOT_EXPR, boolean_type_node, comp); + finish_return_stmt (neg); + } + } + else + { + tree comp = build_new_op (info.loc, SPACESHIP_EXPR, flags, lhs, rhs, + NULL_TREE, NULL_TREE, NULL, complain); + tree comp2 = build_new_op (info.loc, code, flags, comp, integer_zero_node, + NULL_TREE, NULL_TREE, NULL, complain); + info.check (comp2); + if (defining) + finish_return_stmt (comp2); + } + + out: + if (defining) + finish_compound_stmt (compound_stmt); + else + --cp_unevaluated_operand; +} + +/* True iff DECL is an implicitly-declared special member function with no real + source location, so we can use its DECL_SOURCE_LOCATION to remember where we + triggered its synthesis. */ + +bool +decl_remember_implicit_trigger_p (tree decl) +{ + if (!DECL_ARTIFICIAL (decl)) + return false; + special_function_kind sfk = special_function_p (decl); + /* Inherited constructors have the location of their using-declaration, and + operator== has the location of the corresponding operator<=>. */ + return (sfk != sfk_inheriting_constructor + && sfk != sfk_comparison); +} + +/* Synthesize FNDECL, a non-static member function. */ + +void +synthesize_method (tree fndecl) +{ + bool nested = (current_function_decl != NULL_TREE); + tree context = decl_function_context (fndecl); + bool need_body = true; + tree stmt; + location_t save_input_location = input_location; + int error_count = errorcount; + int warning_count = warningcount + werrorcount; + special_function_kind sfk = special_function_p (fndecl); + + /* Reset the source location, we might have been previously + deferred, and thus have saved where we were first needed. */ + if (decl_remember_implicit_trigger_p (fndecl)) + DECL_SOURCE_LOCATION (fndecl) + = DECL_SOURCE_LOCATION (TYPE_NAME (DECL_CONTEXT (fndecl))); + + /* If we've been asked to synthesize a clone, just synthesize the + cloned function instead. Doing so will automatically fill in the + body for the clone. */ + if (DECL_CLONED_FUNCTION_P (fndecl)) + fndecl = DECL_CLONED_FUNCTION (fndecl); + + /* We may be in the middle of deferred access check. Disable + it now. */ + push_deferring_access_checks (dk_no_deferred); + + if (! context) + push_to_top_level (); + else if (nested) + push_function_context (); + + input_location = DECL_SOURCE_LOCATION (fndecl); + + start_preparsed_function (fndecl, NULL_TREE, SF_DEFAULT | SF_PRE_PARSED); + stmt = begin_function_body (); + + if (DECL_ASSIGNMENT_OPERATOR_P (fndecl) + && DECL_OVERLOADED_OPERATOR_IS (fndecl, NOP_EXPR)) + { + do_build_copy_assign (fndecl); + need_body = false; + } + else if (DECL_CONSTRUCTOR_P (fndecl)) + { + tree arg_chain = FUNCTION_FIRST_USER_PARMTYPE (fndecl); + if (arg_chain != void_list_node) + do_build_copy_constructor (fndecl); + else + finish_mem_initializers (NULL_TREE); + } + else if (sfk == sfk_comparison) + { + /* Pass tf_none so the function is just deleted if there's a problem. */ + build_comparison_op (fndecl, true, tf_none); + need_body = false; + } + + /* If we haven't yet generated the body of the function, just + generate an empty compound statement. */ + if (need_body) + { + tree compound_stmt; + compound_stmt = begin_compound_stmt (BCS_FN_BODY); + finish_compound_stmt (compound_stmt); + } + + finish_function_body (stmt); + finish_function (/*inline_p=*/false); + + if (!DECL_DELETED_FN (fndecl)) + expand_or_defer_fn (fndecl); + + input_location = save_input_location; + + if (! context) + pop_from_top_level (); + else if (nested) + pop_function_context (); + + pop_deferring_access_checks (); + + if (error_count != errorcount || warning_count != warningcount + werrorcount) + if (DECL_ARTIFICIAL (fndecl)) + inform (input_location, "synthesized method %qD first required here", + fndecl); +} + +/* Like synthesize_method, but don't actually synthesize defaulted comparison + methods if their class is still incomplete. Just deduce the return + type in that case. */ + +void +maybe_synthesize_method (tree fndecl) +{ + if (special_function_p (fndecl) == sfk_comparison) + { + tree lhs = DECL_ARGUMENTS (fndecl); + if (is_this_parameter (lhs)) + lhs = cp_build_fold_indirect_ref (lhs); + else + lhs = convert_from_reference (lhs); + tree ctype = TYPE_MAIN_VARIANT (TREE_TYPE (lhs)); + if (!COMPLETE_TYPE_P (ctype)) + { + push_deferring_access_checks (dk_no_deferred); + build_comparison_op (fndecl, false, tf_none); + pop_deferring_access_checks (); + return; + } + } + return synthesize_method (fndecl); +} + +/* Build a reference to type TYPE with cv-quals QUALS, which is an + rvalue if RVALUE is true. */ + +static tree +build_stub_type (tree type, int quals, bool rvalue) +{ + tree argtype = cp_build_qualified_type (type, quals); + return cp_build_reference_type (argtype, rvalue); +} + +/* Build a dummy glvalue from dereferencing a dummy reference of type + REFTYPE. */ + +tree +build_stub_object (tree reftype) +{ + if (!TYPE_REF_P (reftype)) + reftype = cp_build_reference_type (reftype, /*rval*/true); + tree stub = build1 (CONVERT_EXPR, reftype, integer_one_node); + return convert_from_reference (stub); +} + +/* Determine which function will be called when looking up NAME in TYPE, + called with a single ARGTYPE argument, or no argument if ARGTYPE is + null. FLAGS and COMPLAIN are as for build_new_method_call. + + Returns a FUNCTION_DECL if all is well. + Returns NULL_TREE if overload resolution failed. + Returns error_mark_node if the chosen function cannot be called. */ + +static tree +locate_fn_flags (tree type, tree name, tree argtype, int flags, + tsubst_flags_t complain) +{ + tree ob, fn, fns, binfo, rval; + + if (TYPE_P (type)) + binfo = TYPE_BINFO (type); + else + { + binfo = type; + type = BINFO_TYPE (binfo); + } + + ob = build_stub_object (cp_build_reference_type (type, false)); + releasing_vec args; + if (argtype) + { + if (TREE_CODE (argtype) == TREE_LIST) + { + for (tree elt = argtype; elt && elt != void_list_node; + elt = TREE_CHAIN (elt)) + { + tree type = TREE_VALUE (elt); + tree arg = build_stub_object (type); + vec_safe_push (args, arg); + } + } + else + { + tree arg = build_stub_object (argtype); + args->quick_push (arg); + } + } + + fns = lookup_fnfields (binfo, name, 0, complain); + rval = build_new_method_call (ob, fns, &args, binfo, flags, &fn, complain); + + if (fn && rval == error_mark_node) + return rval; + else + return fn; +} + +/* Locate the dtor of TYPE. */ + +tree +get_dtor (tree type, tsubst_flags_t complain) +{ + tree fn = locate_fn_flags (type, complete_dtor_identifier, NULL_TREE, + LOOKUP_NORMAL, complain); + if (fn == error_mark_node) + return NULL_TREE; + return fn; +} + +/* Locate the default ctor of TYPE. */ + +tree +locate_ctor (tree type) +{ + tree fn; + + push_deferring_access_checks (dk_no_check); + fn = locate_fn_flags (type, complete_ctor_identifier, NULL_TREE, + LOOKUP_SPECULATIVE, tf_none); + pop_deferring_access_checks (); + if (fn == error_mark_node) + return NULL_TREE; + return fn; +} + +/* Likewise, but give any appropriate errors. */ + +tree +get_default_ctor (tree type) +{ + tree fn = locate_fn_flags (type, complete_ctor_identifier, NULL_TREE, + LOOKUP_NORMAL, tf_warning_or_error); + if (fn == error_mark_node) + return NULL_TREE; + return fn; +} + +/* Locate the copy ctor of TYPE. */ + +tree +get_copy_ctor (tree type, tsubst_flags_t complain) +{ + int quals = (TYPE_HAS_CONST_COPY_CTOR (type) + ? TYPE_QUAL_CONST : TYPE_UNQUALIFIED); + tree argtype = build_stub_type (type, quals, false); + tree fn = locate_fn_flags (type, complete_ctor_identifier, argtype, + LOOKUP_NORMAL, complain); + if (fn == error_mark_node) + return NULL_TREE; + return fn; +} + +/* Locate the copy assignment operator of TYPE. */ + +tree +get_copy_assign (tree type) +{ + int quals = (TYPE_HAS_CONST_COPY_ASSIGN (type) + ? TYPE_QUAL_CONST : TYPE_UNQUALIFIED); + tree argtype = build_stub_type (type, quals, false); + tree fn = locate_fn_flags (type, assign_op_identifier, argtype, + LOOKUP_NORMAL, tf_warning_or_error); + if (fn == error_mark_node) + return NULL_TREE; + return fn; +} + +/* walk_tree helper function for is_trivially_xible. If *TP is a call, + return it if it calls something other than a trivial special member + function. */ + +static tree +check_nontriv (tree *tp, int *, void *) +{ + tree fn = cp_get_callee (*tp); + if (fn == NULL_TREE) + return NULL_TREE; + + if (TREE_CODE (fn) == ADDR_EXPR) + fn = TREE_OPERAND (fn, 0); + + if (TREE_CODE (fn) != FUNCTION_DECL + || !trivial_fn_p (fn)) + return fn; + return NULL_TREE; +} + +/* Return declval<T>() = declval<U>() treated as an unevaluated operand. */ + +static tree +assignable_expr (tree to, tree from) +{ + cp_unevaluated cp_uneval_guard; + to = build_stub_object (to); + from = build_stub_object (from); + tree r = cp_build_modify_expr (input_location, to, NOP_EXPR, from, tf_none); + return r; +} + +/* The predicate condition for a template specialization + is_constructible<T, Args...> shall be satisfied if and only if the + following variable definition would be well-formed for some invented + variable t: T t(create<Args>()...); + + Return something equivalent in well-formedness and triviality. */ + +static tree +constructible_expr (tree to, tree from) +{ + tree expr; + cp_unevaluated cp_uneval_guard; + if (CLASS_TYPE_P (to)) + { + tree ctype = to; + vec<tree, va_gc> *args = NULL; + if (!TYPE_REF_P (to)) + to = cp_build_reference_type (to, /*rval*/false); + tree ob = build_stub_object (to); + for (; from; from = TREE_CHAIN (from)) + vec_safe_push (args, build_stub_object (TREE_VALUE (from))); + expr = build_special_member_call (ob, complete_ctor_identifier, &args, + ctype, LOOKUP_NORMAL, tf_none); + if (expr == error_mark_node) + return error_mark_node; + /* The current state of the standard vis-a-vis LWG 2116 is that + is_*constructible involves destruction as well. */ + if (type_build_dtor_call (ctype)) + { + tree dtor = build_special_member_call (ob, complete_dtor_identifier, + NULL, ctype, LOOKUP_NORMAL, + tf_none); + if (dtor == error_mark_node) + return error_mark_node; + if (!TYPE_HAS_TRIVIAL_DESTRUCTOR (ctype)) + expr = build2 (COMPOUND_EXPR, void_type_node, expr, dtor); + } + } + else + { + if (from == NULL_TREE) + return build_value_init (strip_array_types (to), tf_none); + const int len = list_length (from); + if (len > 1) + { + if (cxx_dialect < cxx20) + /* Too many initializers. */ + return error_mark_node; + + /* In C++20 this is well-formed: + using T = int[2]; + T t(1, 2); + which means that std::is_constructible_v<int[2], int, int> + should be true. */ + vec<constructor_elt, va_gc> *v; + vec_alloc (v, len); + for (tree t = from; t; t = TREE_CHAIN (t)) + { + tree stub = build_stub_object (TREE_VALUE (t)); + constructor_elt elt = { NULL_TREE, stub }; + v->quick_push (elt); + } + from = build_constructor (init_list_type_node, v); + CONSTRUCTOR_IS_DIRECT_INIT (from) = true; + CONSTRUCTOR_IS_PAREN_INIT (from) = true; + } + else + from = build_stub_object (TREE_VALUE (from)); + expr = perform_direct_initialization_if_possible (to, from, + /*cast*/false, + tf_none); + /* If t(e) didn't work, maybe t{e} will. */ + if (expr == NULL_TREE + && len == 1 + && cxx_dialect >= cxx20) + { + from = build_constructor_single (init_list_type_node, NULL_TREE, + from); + CONSTRUCTOR_IS_DIRECT_INIT (from) = true; + CONSTRUCTOR_IS_PAREN_INIT (from) = true; + expr = perform_direct_initialization_if_possible (to, from, + /*cast*/false, + tf_none); + } + } + return expr; +} + +/* Returns a tree iff TO is assignable (if CODE is MODIFY_EXPR) or + constructible (otherwise) from FROM, which is a single type for + assignment or a list of types for construction. */ + +static tree +is_xible_helper (enum tree_code code, tree to, tree from, bool trivial) +{ + to = complete_type (to); + deferring_access_check_sentinel acs (dk_no_deferred); + if (VOID_TYPE_P (to) || ABSTRACT_CLASS_TYPE_P (to) + || (from && FUNC_OR_METHOD_TYPE_P (from) + && (TYPE_READONLY (from) || FUNCTION_REF_QUALIFIED (from)))) + return error_mark_node; + tree expr; + if (code == MODIFY_EXPR) + expr = assignable_expr (to, from); + else if (trivial && from && TREE_CHAIN (from) + && cxx_dialect < cxx20) + return error_mark_node; // only 0- and 1-argument ctors can be trivial + // before C++20 aggregate paren init + else if (TREE_CODE (to) == ARRAY_TYPE && !TYPE_DOMAIN (to)) + return error_mark_node; // can't construct an array of unknown bound + else + expr = constructible_expr (to, from); + return expr; +} + +/* Returns true iff TO is trivially assignable (if CODE is MODIFY_EXPR) or + constructible (otherwise) from FROM, which is a single type for + assignment or a list of types for construction. */ + +bool +is_trivially_xible (enum tree_code code, tree to, tree from) +{ + tree expr = is_xible_helper (code, to, from, /*trivial*/true); + if (expr == NULL_TREE || expr == error_mark_node) + return false; + tree nt = cp_walk_tree_without_duplicates (&expr, check_nontriv, NULL); + return !nt; +} + +/* Returns true iff TO is nothrow assignable (if CODE is MODIFY_EXPR) or + constructible (otherwise) from FROM, which is a single type for + assignment or a list of types for construction. */ + +bool +is_nothrow_xible (enum tree_code code, tree to, tree from) +{ + tree expr = is_xible_helper (code, to, from, /*trivial*/false); + if (expr == NULL_TREE || expr == error_mark_node) + return false; + return expr_noexcept_p (expr, tf_none); +} + +/* Returns true iff TO is assignable (if CODE is MODIFY_EXPR) or + constructible (otherwise) from FROM, which is a single type for + assignment or a list of types for construction. */ + +bool +is_xible (enum tree_code code, tree to, tree from) +{ + tree expr = is_xible_helper (code, to, from, /*trivial*/false); + if (expr == error_mark_node) + return false; + return !!expr; +} + +/* Categorize various special_function_kinds. */ +#define SFK_CTOR_P(sfk) \ + ((sfk) >= sfk_constructor && (sfk) <= sfk_move_constructor) +#define SFK_DTOR_P(sfk) \ + ((sfk) == sfk_destructor || (sfk) == sfk_virtual_destructor) +#define SFK_ASSIGN_P(sfk) \ + ((sfk) == sfk_copy_assignment || (sfk) == sfk_move_assignment) +#define SFK_COPY_P(sfk) \ + ((sfk) == sfk_copy_constructor || (sfk) == sfk_copy_assignment) +#define SFK_MOVE_P(sfk) \ + ((sfk) == sfk_move_constructor || (sfk) == sfk_move_assignment) + +/* Subroutine of synthesized_method_walk. Update SPEC_P, TRIVIAL_P and + DELETED_P or give an error message MSG with argument ARG. */ + +static void +process_subob_fn (tree fn, special_function_kind sfk, tree *spec_p, + bool *trivial_p, bool *deleted_p, bool *constexpr_p, + bool diag, tree arg, bool dtor_from_ctor = false) +{ + if (!fn || fn == error_mark_node) + { + if (deleted_p) + *deleted_p = true; + return; + } + + if (spec_p) + { + if (!maybe_instantiate_noexcept (fn)) + *spec_p = error_mark_node; + else + { + tree raises = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn)); + *spec_p = merge_exception_specifiers (*spec_p, raises); + } + } + + if (!trivial_fn_p (fn) && !dtor_from_ctor) + { + if (trivial_p) + *trivial_p = false; + if (TREE_CODE (arg) == FIELD_DECL + && TREE_CODE (DECL_CONTEXT (arg)) == UNION_TYPE) + { + if (deleted_p) + *deleted_p = true; + if (diag) + error ("union member %q+D with non-trivial %qD", arg, fn); + } + } + + if (constexpr_p && !DECL_DECLARED_CONSTEXPR_P (fn)) + { + *constexpr_p = false; + if (diag) + { + inform (DECL_SOURCE_LOCATION (fn), + SFK_DTOR_P (sfk) + ? G_("defaulted destructor calls non-%<constexpr%> %qD") + : G_("defaulted constructor calls non-%<constexpr%> %qD"), + fn); + explain_invalid_constexpr_fn (fn); + } + } +} + +/* Subroutine of synthesized_method_walk to allow recursion into anonymous + aggregates. If DTOR_FROM_CTOR is true, we're walking subobject destructors + called from a synthesized constructor, in which case we don't consider + the triviality of the subobject destructor. */ + +static void +walk_field_subobs (tree fields, special_function_kind sfk, tree fnname, + int quals, tree *spec_p, bool *trivial_p, + bool *deleted_p, bool *constexpr_p, + bool diag, int flags, tsubst_flags_t complain, + bool dtor_from_ctor) +{ + tree field; + for (field = fields; field; field = DECL_CHAIN (field)) + { + tree mem_type, argtype, rval; + + if (TREE_CODE (field) != FIELD_DECL + || DECL_ARTIFICIAL (field) + || DECL_UNNAMED_BIT_FIELD (field)) + continue; + + /* Variant members only affect deletedness. In particular, they don't + affect the exception-specification of a user-provided destructor, + which we're figuring out via get_defaulted_eh_spec. So if we aren't + asking if this is deleted, don't even look up the function; we don't + want an error about a deleted function we aren't actually calling. */ + if (sfk == sfk_destructor && deleted_p == NULL + && TREE_CODE (DECL_CONTEXT (field)) == UNION_TYPE) + break; + + mem_type = strip_array_types (TREE_TYPE (field)); + if (SFK_ASSIGN_P (sfk)) + { + bool bad = true; + if (CP_TYPE_CONST_P (mem_type) && !CLASS_TYPE_P (mem_type)) + { + if (diag) + error ("non-static const member %q#D, cannot use default " + "assignment operator", field); + } + else if (TYPE_REF_P (mem_type)) + { + if (diag) + error ("non-static reference member %q#D, cannot use " + "default assignment operator", field); + } + else + bad = false; + + if (bad && deleted_p) + *deleted_p = true; + } + else if (sfk == sfk_constructor || sfk == sfk_inheriting_constructor) + { + bool bad; + + if (DECL_INITIAL (field)) + { + if (diag && DECL_INITIAL (field) == error_mark_node) + inform (DECL_SOURCE_LOCATION (field), + "initializer for %q#D is invalid", field); + if (trivial_p) + *trivial_p = false; + /* Core 1351: If the field has an NSDMI that could throw, the + default constructor is noexcept(false). */ + if (spec_p) + { + tree nsdmi = get_nsdmi (field, /*ctor*/false, complain); + if (nsdmi == error_mark_node) + *spec_p = error_mark_node; + else if (*spec_p != error_mark_node + && !expr_noexcept_p (nsdmi, tf_none)) + *spec_p = noexcept_false_spec; + } + /* Don't do the normal processing. */ + continue; + } + + bad = false; + if (CP_TYPE_CONST_P (mem_type) + && default_init_uninitialized_part (mem_type)) + { + if (diag) + { + error ("uninitialized const member in %q#T", + current_class_type); + inform (DECL_SOURCE_LOCATION (field), + "%q#D should be initialized", field); + } + bad = true; + } + else if (TYPE_REF_P (mem_type)) + { + if (diag) + { + error ("uninitialized reference member in %q#T", + current_class_type); + inform (DECL_SOURCE_LOCATION (field), + "%q#D should be initialized", field); + } + bad = true; + } + + if (bad && deleted_p) + *deleted_p = true; + + /* Before C++20, for an implicitly-defined default constructor to + be constexpr, every member must have a user-provided default + constructor or an explicit initializer. */ + if (constexpr_p + && cxx_dialect < cxx20 + && !CLASS_TYPE_P (mem_type) + && TREE_CODE (DECL_CONTEXT (field)) != UNION_TYPE) + { + *constexpr_p = false; + if (diag) + inform (DECL_SOURCE_LOCATION (field), + "defaulted default constructor does not " + "initialize %q#D", field); + } + } + else if (sfk == sfk_copy_constructor) + { + /* 12.8p11b5 */ + if (TYPE_REF_P (mem_type) + && TYPE_REF_IS_RVALUE (mem_type)) + { + if (diag) + error ("copying non-static data member %q#D of rvalue " + "reference type", field); + if (deleted_p) + *deleted_p = true; + } + } + + if (!CLASS_TYPE_P (mem_type)) + continue; + + if (ANON_AGGR_TYPE_P (mem_type)) + { + walk_field_subobs (TYPE_FIELDS (mem_type), sfk, fnname, quals, + spec_p, trivial_p, deleted_p, constexpr_p, + diag, flags, complain, dtor_from_ctor); + continue; + } + + if (SFK_COPY_P (sfk) || SFK_MOVE_P (sfk)) + { + int mem_quals = cp_type_quals (mem_type) | quals; + if (DECL_MUTABLE_P (field)) + mem_quals &= ~TYPE_QUAL_CONST; + argtype = build_stub_type (mem_type, mem_quals, SFK_MOVE_P (sfk)); + } + else + argtype = NULL_TREE; + + rval = locate_fn_flags (mem_type, fnname, argtype, flags, complain); + + process_subob_fn (rval, sfk, spec_p, trivial_p, deleted_p, + constexpr_p, diag, field, dtor_from_ctor); + } +} + +/* Base walker helper for synthesized_method_walk. Inspect a direct + or virtual base. BINFO is the parent type's binfo. BASE_BINFO is + the base binfo of interests. All other parms are as for + synthesized_method_walk, or its local vars. */ + +static tree +synthesized_method_base_walk (tree binfo, tree base_binfo, + special_function_kind sfk, tree fnname, int quals, + tree *inheriting_ctor, tree inherited_parms, + int flags, bool diag, + tree *spec_p, bool *trivial_p, + bool *deleted_p, bool *constexpr_p) +{ + bool inherited_binfo = false; + tree argtype = NULL_TREE; + deferring_kind defer = dk_no_deferred; + + if (SFK_COPY_P (sfk) || SFK_MOVE_P (sfk)) + argtype = build_stub_type (BINFO_TYPE (base_binfo), quals, SFK_MOVE_P (sfk)); + else if (inheriting_ctor + && (inherited_binfo + = binfo_inherited_from (binfo, base_binfo, *inheriting_ctor))) + { + argtype = inherited_parms; + /* Don't check access on the inherited constructor. */ + if (flag_new_inheriting_ctors) + defer = dk_deferred; + } + else if (cxx_dialect >= cxx14 && sfk == sfk_virtual_destructor + && BINFO_VIRTUAL_P (base_binfo) + && ABSTRACT_CLASS_TYPE_P (BINFO_TYPE (binfo))) + /* Don't check access when looking at vbases of abstract class's + virtual destructor. */ + defer = dk_no_check; + + if (defer != dk_no_deferred) + push_deferring_access_checks (defer); + tree rval = locate_fn_flags (base_binfo, fnname, argtype, flags, + diag ? tf_warning_or_error : tf_none); + if (defer != dk_no_deferred) + pop_deferring_access_checks (); + + /* Replace an inherited template with the appropriate specialization. */ + if (inherited_binfo && rval + && DECL_P (*inheriting_ctor) && DECL_P (rval) + && DECL_CONTEXT (*inheriting_ctor) == DECL_CONTEXT (rval)) + *inheriting_ctor = DECL_CLONED_FUNCTION (rval); + + process_subob_fn (rval, sfk, spec_p, trivial_p, deleted_p, + constexpr_p, diag, BINFO_TYPE (base_binfo)); + if (SFK_CTOR_P (sfk) + && (!BINFO_VIRTUAL_P (base_binfo) + || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (BINFO_TYPE (base_binfo)))) + { + /* In a constructor we also need to check the subobject + destructors for cleanup of partially constructed objects. */ + tree dtor = locate_fn_flags (base_binfo, complete_dtor_identifier, + NULL_TREE, flags, + diag ? tf_warning_or_error : tf_none); + /* Note that we don't pass down trivial_p; the subobject + destructors don't affect triviality of the constructor. Nor + do they affect constexpr-ness (a constant expression doesn't + throw) or exception-specification (a throw from one of the + dtors would be a double-fault). */ + process_subob_fn (dtor, sfk, NULL, NULL, deleted_p, NULL, false, + BINFO_TYPE (base_binfo), /*dtor_from_ctor*/true); + } + + return rval; +} + +/* The caller wants to generate an implicit declaration of SFK for + CTYPE which is const if relevant and CONST_P is set. If SPEC_P, + TRIVIAL_P, DELETED_P or CONSTEXPR_P are non-null, set their + referent appropriately. If DIAG is true, we're either being called + from maybe_explain_implicit_delete to give errors, or if + CONSTEXPR_P is non-null, from explain_invalid_constexpr_fn. */ + +static void +synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p, + tree *spec_p, bool *trivial_p, bool *deleted_p, + bool *constexpr_p, bool diag, + tree *inheriting_ctor, tree inherited_parms) +{ + tree binfo, base_binfo; + int i; + + /* SFK must be exactly one category. */ + gcc_checking_assert (SFK_DTOR_P(sfk) + SFK_CTOR_P(sfk) + + SFK_ASSIGN_P(sfk) == 1); + + if (spec_p) + *spec_p = (cxx_dialect >= cxx11 ? noexcept_true_spec : empty_except_spec); + + if (deleted_p) + { + /* "The closure type associated with a lambda-expression has a deleted + default constructor and a deleted copy assignment operator." + This is diagnosed in maybe_explain_implicit_delete. + In C++20, only lambda-expressions with lambda-captures have those + deleted. */ + if (LAMBDA_TYPE_P (ctype) + && (sfk == sfk_constructor || sfk == sfk_copy_assignment) + && (cxx_dialect < cxx20 + || LAMBDA_EXPR_CAPTURE_LIST (CLASSTYPE_LAMBDA_EXPR (ctype)) + || LAMBDA_EXPR_DEFAULT_CAPTURE_MODE + (CLASSTYPE_LAMBDA_EXPR (ctype)) != CPLD_NONE)) + { + *deleted_p = true; + return; + } + + *deleted_p = false; + } + + bool check_vdtor = false; + tree fnname; + + if (SFK_DTOR_P (sfk)) + { + check_vdtor = true; + /* The synthesized method will call base dtors, but check complete + here to avoid having to deal with VTT. */ + fnname = complete_dtor_identifier; + } + else if (SFK_ASSIGN_P (sfk)) + fnname = assign_op_identifier; + else + fnname = complete_ctor_identifier; + + gcc_assert ((sfk == sfk_inheriting_constructor) + == (inheriting_ctor && *inheriting_ctor != NULL_TREE)); + + /* If that user-written default constructor would satisfy the + requirements of a constexpr constructor (7.1.5), the + implicitly-defined default constructor is constexpr. + + The implicitly-defined copy/move assignment operator is constexpr if + - X is a literal type, and + - the assignment operator selected to copy/move each direct base class + subobject is a constexpr function, and + - for each non-static data member of X that is of class type (or array + thereof), the assignment operator selected to copy/move that + member is a constexpr function. */ + if (constexpr_p) + *constexpr_p = (SFK_CTOR_P (sfk) + || (SFK_ASSIGN_P (sfk) && cxx_dialect >= cxx14) + || (SFK_DTOR_P (sfk) && cxx_dialect >= cxx20)); + + bool expected_trivial = type_has_trivial_fn (ctype, sfk); + if (trivial_p) + *trivial_p = expected_trivial; + + /* The TYPE_HAS_COMPLEX_* flags tell us about constraints from base + class versions and other properties of the type. But a subobject + class can be trivially copyable and yet have overload resolution + choose a template constructor for initialization, depending on + rvalueness and cv-quals. And furthermore, a member in a base might + be trivial but deleted or otherwise not callable. So we can't exit + early in C++0x. The same considerations apply in C++98/03, but + there the definition of triviality does not consider overload + resolution, so a constructor can be trivial even if it would otherwise + call a non-trivial constructor. */ + if (expected_trivial + && (!(SFK_COPY_P (sfk) || SFK_MOVE_P (sfk)) || cxx_dialect < cxx11)) + { + if (constexpr_p && sfk == sfk_constructor) + { + bool cx = trivial_default_constructor_is_constexpr (ctype); + *constexpr_p = cx; + if (diag && !cx && TREE_CODE (ctype) == UNION_TYPE) + /* A trivial constructor doesn't have any NSDMI. */ + inform (input_location, "defaulted default constructor does " + "not initialize any non-static data member"); + } + if (!diag && cxx_dialect < cxx11) + return; + } + + ++cp_unevaluated_operand; + ++c_inhibit_evaluation_warnings; + push_deferring_access_checks (dk_no_deferred); + + tree scope = push_scope (ctype); + + int flags = LOOKUP_NORMAL | LOOKUP_SPECULATIVE; + if (sfk != sfk_inheriting_constructor) + flags |= LOOKUP_DEFAULTED; + + tsubst_flags_t complain = diag ? tf_warning_or_error : tf_none; + if (diag && spec_p) + /* We're in get_defaulted_eh_spec; we don't actually want any walking + diagnostics, we just want complain set. */ + diag = false; + int quals = const_p ? TYPE_QUAL_CONST : TYPE_UNQUALIFIED; + + for (binfo = TYPE_BINFO (ctype), i = 0; + BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i) + { + if (!SFK_ASSIGN_P (sfk) && BINFO_VIRTUAL_P (base_binfo)) + /* We'll handle virtual bases below. */ + continue; + + tree fn = synthesized_method_base_walk (binfo, base_binfo, + sfk, fnname, quals, + inheriting_ctor, inherited_parms, + flags, diag, spec_p, trivial_p, + deleted_p, constexpr_p); + + if (diag && SFK_ASSIGN_P (sfk) && SFK_MOVE_P (sfk) + && BINFO_VIRTUAL_P (base_binfo) + && fn && TREE_CODE (fn) == FUNCTION_DECL + && move_fn_p (fn) && !trivial_fn_p (fn) + && vbase_has_user_provided_move_assign (BINFO_TYPE (base_binfo))) + warning (OPT_Wvirtual_move_assign, + "defaulted move assignment for %qT calls a non-trivial " + "move assignment operator for virtual base %qT", + ctype, BINFO_TYPE (base_binfo)); + + if (check_vdtor && type_has_virtual_destructor (BINFO_TYPE (base_binfo))) + { + /* Unlike for base ctor/op=/dtor, for operator delete it's fine + to have a null fn (no class-specific op delete). */ + fn = locate_fn_flags (ctype, ovl_op_identifier (false, DELETE_EXPR), + ptr_type_node, flags, tf_none); + if (fn && fn == error_mark_node) + { + if (complain & tf_error) + locate_fn_flags (ctype, ovl_op_identifier (false, DELETE_EXPR), + ptr_type_node, flags, complain); + if (deleted_p) + *deleted_p = true; + } + check_vdtor = false; + } + } + + vec<tree, va_gc> *vbases = CLASSTYPE_VBASECLASSES (ctype); + if (SFK_ASSIGN_P (sfk)) + /* Already examined vbases above. */; + else if (vec_safe_is_empty (vbases)) + /* No virtual bases to worry about. */; + else if (ABSTRACT_CLASS_TYPE_P (ctype) && cxx_dialect >= cxx14 + /* DR 1658 specifies that vbases of abstract classes are + ignored for both ctors and dtors. Except DR 2336 + overrides that skipping when determing the eh-spec of a + virtual destructor. */ + && sfk != sfk_virtual_destructor) + /* Vbase cdtors are not relevant. */; + else + { + if (constexpr_p) + *constexpr_p = false; + + FOR_EACH_VEC_ELT (*vbases, i, base_binfo) + synthesized_method_base_walk (binfo, base_binfo, sfk, fnname, quals, + inheriting_ctor, inherited_parms, + flags, diag, + spec_p, trivial_p, deleted_p, constexpr_p); + } + + /* Now handle the non-static data members. */ + walk_field_subobs (TYPE_FIELDS (ctype), sfk, fnname, quals, + spec_p, trivial_p, deleted_p, constexpr_p, + diag, flags, complain, /*dtor_from_ctor*/false); + if (SFK_CTOR_P (sfk)) + walk_field_subobs (TYPE_FIELDS (ctype), sfk_destructor, + complete_dtor_identifier, TYPE_UNQUALIFIED, + NULL, NULL, deleted_p, NULL, + false, flags, complain, /*dtor_from_ctor*/true); + + pop_scope (scope); + + pop_deferring_access_checks (); + --cp_unevaluated_operand; + --c_inhibit_evaluation_warnings; +} + +/* DECL is a defaulted function whose exception specification is now + needed. Return what it should be. */ + +tree +get_defaulted_eh_spec (tree decl, tsubst_flags_t complain) +{ + /* For DECL_MAYBE_DELETED this should already have been handled by + synthesize_method. */ + gcc_assert (!DECL_MAYBE_DELETED (decl)); + + if (DECL_CLONED_FUNCTION_P (decl)) + decl = DECL_CLONED_FUNCTION (decl); + special_function_kind sfk = special_function_p (decl); + tree ctype = DECL_CONTEXT (decl); + tree parms = FUNCTION_FIRST_USER_PARMTYPE (decl); + tree parm_type = TREE_VALUE (parms); + bool const_p = CP_TYPE_CONST_P (non_reference (parm_type)); + tree spec = empty_except_spec; + bool diag = !DECL_DELETED_FN (decl) && (complain & tf_error); + tree inh = DECL_INHERITED_CTOR (decl); + if (SFK_DTOR_P (sfk) && DECL_VIRTUAL_P (decl)) + /* We have to examine virtual bases even if abstract. */ + sfk = sfk_virtual_destructor; + bool pushed = false; + if (CLASSTYPE_TEMPLATE_INSTANTIATION (ctype)) + pushed = push_tinst_level (decl); + synthesized_method_walk (ctype, sfk, const_p, &spec, NULL, NULL, + NULL, diag, &inh, parms); + if (pushed) + pop_tinst_level (); + return spec; +} + +/* DECL is a deleted function. If it's implicitly deleted, explain why and + return true; else return false. */ + +bool +maybe_explain_implicit_delete (tree decl) +{ + /* If decl is a clone, get the primary variant. */ + decl = DECL_ORIGIN (decl); + gcc_assert (DECL_DELETED_FN (decl)); + if (DECL_DEFAULTED_FN (decl)) + { + /* Not marked GTY; it doesn't need to be GC'd or written to PCH. */ + static hash_set<tree> *explained; + + special_function_kind sfk; + location_t loc; + bool informed; + tree ctype; + + if (!explained) + explained = new hash_set<tree>; + if (explained->add (decl)) + return true; + + sfk = special_function_p (decl); + ctype = DECL_CONTEXT (decl); + loc = input_location; + input_location = DECL_SOURCE_LOCATION (decl); + + informed = false; + if (LAMBDA_TYPE_P (ctype)) + { + informed = true; + if (sfk == sfk_constructor) + inform (DECL_SOURCE_LOCATION (decl), + "a lambda closure type has a deleted default constructor"); + else if (sfk == sfk_copy_assignment) + inform (DECL_SOURCE_LOCATION (decl), + "a lambda closure type has a deleted copy assignment operator"); + else + informed = false; + } + else if (DECL_ARTIFICIAL (decl) + && (sfk == sfk_copy_assignment || sfk == sfk_copy_constructor) + && classtype_has_move_assign_or_move_ctor_p (ctype, true)) + { + inform (DECL_SOURCE_LOCATION (decl), + "%q#D is implicitly declared as deleted because %qT " + "declares a move constructor or move assignment operator", + decl, ctype); + informed = true; + } + else if (sfk == sfk_inheriting_constructor) + { + tree binfo = inherited_ctor_binfo (decl); + if (TREE_CODE (binfo) != TREE_BINFO) + { + inform (DECL_SOURCE_LOCATION (decl), + "%q#D inherits from multiple base subobjects", + decl); + informed = true; + } + } + if (!informed && sfk == sfk_comparison) + { + inform (DECL_SOURCE_LOCATION (decl), + "%q#D is implicitly deleted because the default " + "definition would be ill-formed:", decl); + build_comparison_op (decl, false, tf_warning_or_error); + } + else if (!informed) + { + tree parms = FUNCTION_FIRST_USER_PARMTYPE (decl); + bool const_p = false; + if (parms) + { + tree parm_type = TREE_VALUE (parms); + const_p = CP_TYPE_CONST_P (non_reference (parm_type)); + } + tree raises = NULL_TREE; + bool deleted_p = false; + tree scope = push_scope (ctype); + tree inh = DECL_INHERITED_CTOR (decl); + + synthesized_method_walk (ctype, sfk, const_p, + &raises, NULL, &deleted_p, NULL, false, + &inh, parms); + if (deleted_p) + { + inform (DECL_SOURCE_LOCATION (decl), + "%q#D is implicitly deleted because the default " + "definition would be ill-formed:", decl); + synthesized_method_walk (ctype, sfk, const_p, + NULL, NULL, &deleted_p, NULL, true, + &inh, parms); + } + else if (!comp_except_specs + (TYPE_RAISES_EXCEPTIONS (TREE_TYPE (decl)), + raises, ce_normal)) + inform (DECL_SOURCE_LOCATION (decl), "%q#F is implicitly " + "deleted because its exception-specification does not " + "match the implicit exception-specification %qX", + decl, raises); + else if (flag_checking) + gcc_unreachable (); + + pop_scope (scope); + } + + input_location = loc; + return true; + } + return false; +} + +/* DECL is a defaulted function which was declared constexpr. Explain why + it can't be constexpr. */ + +void +explain_implicit_non_constexpr (tree decl) +{ + tree parms = FUNCTION_FIRST_USER_PARMTYPE (decl); + bool const_p = CP_TYPE_CONST_P (non_reference (TREE_VALUE (parms))); + tree inh = DECL_INHERITED_CTOR (decl); + bool dummy; + special_function_kind sfk = special_function_p (decl); + if (sfk == sfk_comparison) + { + DECL_DECLARED_CONSTEXPR_P (decl) = true; + build_comparison_op (decl, false, tf_warning_or_error); + DECL_DECLARED_CONSTEXPR_P (decl) = false; + } + else + synthesized_method_walk (DECL_CLASS_CONTEXT (decl), + sfk, const_p, + NULL, NULL, NULL, &dummy, true, + &inh, parms); +} + +/* DECL is an instantiation of an inheriting constructor template. Deduce + the correct exception-specification and deletedness for this particular + specialization. Return true if the deduction succeeds; false otherwise. */ + +bool +deduce_inheriting_ctor (tree decl) +{ + decl = DECL_ORIGIN (decl); + gcc_assert (DECL_INHERITED_CTOR (decl)); + tree spec; + bool trivial, constexpr_, deleted; + tree inh = DECL_INHERITED_CTOR (decl); + synthesized_method_walk (DECL_CONTEXT (decl), sfk_inheriting_constructor, + false, &spec, &trivial, &deleted, &constexpr_, + /*diag*/false, + &inh, + FUNCTION_FIRST_USER_PARMTYPE (decl)); + if (spec == error_mark_node) + return false; + if (TREE_CODE (inherited_ctor_binfo (decl)) != TREE_BINFO) + /* Inherited the same constructor from different base subobjects. */ + deleted = true; + DECL_DELETED_FN (decl) = deleted; + TREE_TYPE (decl) = build_exception_variant (TREE_TYPE (decl), spec); + SET_DECL_INHERITED_CTOR (decl, inh); + + tree clone; + FOR_EACH_CLONE (clone, decl) + { + DECL_DELETED_FN (clone) = deleted; + TREE_TYPE (clone) = build_exception_variant (TREE_TYPE (clone), spec); + SET_DECL_INHERITED_CTOR (clone, inh); + } + + return true; +} + +/* Implicitly declare the special function indicated by KIND, as a + member of TYPE. For copy constructors and assignment operators, + CONST_P indicates whether these functions should take a const + reference argument or a non-const reference. + Returns the FUNCTION_DECL for the implicitly declared function. */ + +tree +implicitly_declare_fn (special_function_kind kind, tree type, + bool const_p, tree pattern_fn, + tree inherited_parms) +{ + tree fn; + tree parameter_types = void_list_node; + tree return_type; + tree fn_type; + tree raises = empty_except_spec; + tree rhs_parm_type = NULL_TREE; + tree this_parm; + tree name; + HOST_WIDE_INT saved_processing_template_decl; + bool deleted_p = false; + bool constexpr_p = false; + tree inherited_ctor = (kind == sfk_inheriting_constructor + ? pattern_fn : NULL_TREE); + + /* Because we create declarations for implicitly declared functions + lazily, we may be creating the declaration for a member of TYPE + while in some completely different context. However, TYPE will + never be a dependent class (because we never want to do lookups + for implicitly defined functions in a dependent class). */ + gcc_assert (!dependent_type_p (type)); + + /* If the member-specification does not explicitly declare any member or + friend named operator==, an == operator function is declared + implicitly for each three-way comparison operator function defined as + defaulted in the member-specification, with the same access and + function-definition and in the same class scope as the respective + three-way comparison operator function, except that the return type is + replaced with bool and the declarator-id is replaced with + operator==. + + [Note: Such an implicitly-declared == operator for a class X is + defined as defaulted in the definition of X and has the same + parameter-declaration-clause and trailing requires-clause as the + respective three-way comparison operator. It is declared with friend, + virtual, constexpr, or consteval if the three-way comparison operator + function is so declared. If the three-way comparison operator function + has no noexcept-specifier, the implicitly-declared == operator + function has an implicit exception specification (14.5) that may + differ from the implicit exception specification of the three-way + comparison operator function. --end note] */ + if (kind == sfk_comparison) + { + fn = copy_operator_fn (pattern_fn, EQ_EXPR); + DECL_ARTIFICIAL (fn) = 1; + TREE_TYPE (fn) = change_return_type (boolean_type_node, TREE_TYPE (fn)); + return fn; + } + + /* Furthermore, we must set PROCESSING_TEMPLATE_DECL to zero here + because we only create clones for constructors and destructors + when not in a template. */ + saved_processing_template_decl = processing_template_decl; + processing_template_decl = 0; + + type = TYPE_MAIN_VARIANT (type); + + if (targetm.cxx.cdtor_returns_this ()) + { + if (kind == sfk_destructor) + /* See comment in check_special_function_return_type. */ + return_type = build_pointer_type (void_type_node); + else + return_type = build_pointer_type (type); + } + else + return_type = void_type_node; + + int this_quals = TYPE_UNQUALIFIED; + switch (kind) + { + case sfk_destructor: + /* Destructor. */ + name = dtor_identifier; + break; + + case sfk_constructor: + /* Default constructor. */ + name = ctor_identifier; + break; + + case sfk_copy_constructor: + case sfk_copy_assignment: + case sfk_move_constructor: + case sfk_move_assignment: + case sfk_inheriting_constructor: + { + if (kind == sfk_copy_assignment + || kind == sfk_move_assignment) + { + return_type = build_reference_type (type); + name = assign_op_identifier; + } + else + name = ctor_identifier; + + if (kind == sfk_inheriting_constructor) + parameter_types = inherited_parms; + else + { + if (const_p) + rhs_parm_type = cp_build_qualified_type (type, TYPE_QUAL_CONST); + else + rhs_parm_type = type; + bool move_p = (kind == sfk_move_assignment + || kind == sfk_move_constructor); + rhs_parm_type = cp_build_reference_type (rhs_parm_type, move_p); + + parameter_types = tree_cons (NULL_TREE, rhs_parm_type, parameter_types); + } + break; + } + + default: + gcc_unreachable (); + } + + bool trivial_p = false; + + if (inherited_ctor) + { + /* For an inheriting constructor, just copy these flags from the + inherited constructor until deduce_inheriting_ctor. */ + raises = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (inherited_ctor)); + deleted_p = DECL_DELETED_FN (inherited_ctor); + constexpr_p = DECL_DECLARED_CONSTEXPR_P (inherited_ctor); + } + else if (cxx_dialect >= cxx11) + { + raises = noexcept_deferred_spec; + synthesized_method_walk (type, kind, const_p, NULL, &trivial_p, + &deleted_p, &constexpr_p, false, + &inherited_ctor, inherited_parms); + } + else + synthesized_method_walk (type, kind, const_p, &raises, &trivial_p, + &deleted_p, &constexpr_p, false, + &inherited_ctor, inherited_parms); + /* Don't bother marking a deleted constructor as constexpr. */ + if (deleted_p) + constexpr_p = false; + /* A trivial copy/move constructor is also a constexpr constructor, + unless the class has virtual bases (7.1.5p4). */ + else if (trivial_p + && cxx_dialect >= cxx11 + && (kind == sfk_copy_constructor + || kind == sfk_move_constructor) + && !CLASSTYPE_VBASECLASSES (type)) + gcc_assert (constexpr_p); + + if (!trivial_p && type_has_trivial_fn (type, kind)) + type_set_nontrivial_flag (type, kind); + + /* Create the function. */ + tree this_type = cp_build_qualified_type (type, this_quals); + fn_type = build_method_type_directly (this_type, return_type, + parameter_types); + + if (raises) + { + if (raises != error_mark_node) + fn_type = build_exception_variant (fn_type, raises); + else + { + /* Can happen, e.g., in C++98 mode for an ill-formed non-static data + member initializer (c++/89914). Also, in C++98, we might have + failed to deduce RAISES, so try again but complain this time. */ + if (cxx_dialect < cxx11) + synthesized_method_walk (type, kind, const_p, &raises, nullptr, + nullptr, nullptr, /*diag=*/true, + &inherited_ctor, inherited_parms); + /* We should have seen an error at this point. */ + gcc_assert (seen_error ()); + } + } + fn = build_lang_decl (FUNCTION_DECL, name, fn_type); + if (kind != sfk_inheriting_constructor) + DECL_SOURCE_LOCATION (fn) = DECL_SOURCE_LOCATION (TYPE_NAME (type)); + + if (IDENTIFIER_OVL_OP_P (name)) + { + const ovl_op_info_t *op = IDENTIFIER_OVL_OP_INFO (name); + DECL_OVERLOADED_OPERATOR_CODE_RAW (fn) = op->ovl_op_code; + } + else if (IDENTIFIER_CTOR_P (name)) + DECL_CXX_CONSTRUCTOR_P (fn) = true; + else if (IDENTIFIER_DTOR_P (name)) + DECL_CXX_DESTRUCTOR_P (fn) = true; + else + gcc_unreachable (); + + SET_DECL_ALIGN (fn, MINIMUM_METHOD_BOUNDARY); + + /* Create the explicit arguments. */ + if (rhs_parm_type) + { + /* Note that this parameter is *not* marked DECL_ARTIFICIAL; we + want its type to be included in the mangled function + name. */ + tree decl = cp_build_parm_decl (fn, NULL_TREE, rhs_parm_type); + TREE_READONLY (decl) = 1; + retrofit_lang_decl (decl); + DECL_PARM_INDEX (decl) = DECL_PARM_LEVEL (decl) = 1; + DECL_ARGUMENTS (fn) = decl; + } + else if (kind == sfk_inheriting_constructor) + { + tree *p = &DECL_ARGUMENTS (fn); + int index = 1; + for (tree parm = inherited_parms; parm && parm != void_list_node; + parm = TREE_CHAIN (parm)) + { + *p = cp_build_parm_decl (fn, NULL_TREE, TREE_VALUE (parm)); + retrofit_lang_decl (*p); + DECL_PARM_LEVEL (*p) = 1; + DECL_PARM_INDEX (*p) = index++; + p = &DECL_CHAIN (*p); + } + SET_DECL_INHERITED_CTOR (fn, inherited_ctor); + DECL_NONCONVERTING_P (fn) = DECL_NONCONVERTING_P (inherited_ctor); + /* A constructor so declared has the same access as the corresponding + constructor in X. */ + TREE_PRIVATE (fn) = TREE_PRIVATE (inherited_ctor); + TREE_PROTECTED (fn) = TREE_PROTECTED (inherited_ctor); + /* Copy constexpr from the inherited constructor even if the + inheriting constructor doesn't satisfy the requirements. */ + constexpr_p = DECL_DECLARED_CONSTEXPR_P (inherited_ctor); + } + + /* Add the "this" parameter. */ + this_parm = build_this_parm (fn, fn_type, this_quals); + DECL_CHAIN (this_parm) = DECL_ARGUMENTS (fn); + DECL_ARGUMENTS (fn) = this_parm; + + grokclassfn (type, fn, kind == sfk_destructor ? DTOR_FLAG : NO_SPECIAL); + + DECL_IN_AGGR_P (fn) = 1; + DECL_ARTIFICIAL (fn) = 1; + DECL_DEFAULTED_FN (fn) = 1; + if (cxx_dialect >= cxx11) + { + DECL_DELETED_FN (fn) = deleted_p; + DECL_DECLARED_CONSTEXPR_P (fn) = constexpr_p; + } + DECL_EXTERNAL (fn) = true; + DECL_NOT_REALLY_EXTERN (fn) = 1; + DECL_DECLARED_INLINE_P (fn) = 1; + set_linkage_according_to_type (type, fn); + if (TREE_PUBLIC (fn)) + DECL_COMDAT (fn) = 1; + rest_of_decl_compilation (fn, namespace_bindings_p (), at_eof); + gcc_assert (!TREE_USED (fn)); + + /* Propagate constraints from the inherited constructor. */ + if (flag_concepts && inherited_ctor) + if (tree orig_ci = get_constraints (inherited_ctor)) + { + tree new_ci = copy_node (orig_ci); + set_constraints (fn, new_ci); + } + + /* Restore PROCESSING_TEMPLATE_DECL. */ + processing_template_decl = saved_processing_template_decl; + + if (inherited_ctor && TREE_CODE (inherited_ctor) == TEMPLATE_DECL) + fn = add_inherited_template_parms (fn, inherited_ctor); + + /* Warn about calling a non-trivial move assignment in a virtual base. */ + if (kind == sfk_move_assignment && !deleted_p && !trivial_p + && CLASSTYPE_VBASECLASSES (type)) + { + location_t loc = input_location; + input_location = DECL_SOURCE_LOCATION (fn); + synthesized_method_walk (type, kind, const_p, + NULL, NULL, NULL, NULL, true, + NULL, NULL_TREE); + input_location = loc; + } + + return fn; +} + +/* Gives any errors about defaulted functions which need to be deferred + until the containing class is complete. */ + +void +defaulted_late_check (tree fn) +{ + /* Complain about invalid signature for defaulted fn. */ + tree ctx = DECL_CONTEXT (fn); + special_function_kind kind = special_function_p (fn); + + if (kind == sfk_comparison) + { + /* If the function was declared constexpr, check that the definition + qualifies. Otherwise we can define the function lazily. */ + if (DECL_DECLARED_CONSTEXPR_P (fn) && !DECL_INITIAL (fn)) + { + /* Prevent GC. */ + function_depth++; + synthesize_method (fn); + function_depth--; + } + return; + } + + bool fn_const_p = (copy_fn_p (fn) == 2); + tree implicit_fn = implicitly_declare_fn (kind, ctx, fn_const_p, + NULL, NULL); + tree eh_spec = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (implicit_fn)); + + if (!same_type_p (TREE_TYPE (TREE_TYPE (fn)), + TREE_TYPE (TREE_TYPE (implicit_fn))) + || !compparms (TYPE_ARG_TYPES (TREE_TYPE (fn)), + TYPE_ARG_TYPES (TREE_TYPE (implicit_fn)))) + { + error ("defaulted declaration %q+D does not match the " + "expected signature", fn); + inform (DECL_SOURCE_LOCATION (fn), + "expected signature: %qD", implicit_fn); + } + + if (DECL_DELETED_FN (implicit_fn)) + { + DECL_DELETED_FN (fn) = 1; + return; + } + + /* If a function is explicitly defaulted on its first declaration without an + exception-specification, it is implicitly considered to have the same + exception-specification as if it had been implicitly declared. */ + if (!TYPE_RAISES_EXCEPTIONS (TREE_TYPE (fn)) + && DECL_DEFAULTED_IN_CLASS_P (fn)) + TREE_TYPE (fn) = build_exception_variant (TREE_TYPE (fn), eh_spec); + + if (DECL_DEFAULTED_IN_CLASS_P (fn) + && DECL_DECLARED_CONSTEXPR_P (implicit_fn)) + { + /* Hmm...should we do this for out-of-class too? Should it be OK to + add constexpr later like inline, rather than requiring + declarations to match? */ + DECL_DECLARED_CONSTEXPR_P (fn) = true; + if (kind == sfk_constructor) + TYPE_HAS_CONSTEXPR_CTOR (ctx) = true; + } + + if (!DECL_DECLARED_CONSTEXPR_P (implicit_fn) + && DECL_DECLARED_CONSTEXPR_P (fn)) + { + if (!CLASSTYPE_TEMPLATE_INSTANTIATION (ctx)) + { + error ("explicitly defaulted function %q+D cannot be declared " + "%qs because the implicit declaration is not %qs:", fn, + DECL_IMMEDIATE_FUNCTION_P (fn) ? "consteval" : "constexpr", + "constexpr"); + explain_implicit_non_constexpr (fn); + } + DECL_DECLARED_CONSTEXPR_P (fn) = false; + } +} + +/* Returns true iff FN can be explicitly defaulted, and gives any + errors if defaulting FN is ill-formed. */ + +bool +defaultable_fn_check (tree fn) +{ + special_function_kind kind = sfk_none; + + if (template_parm_scope_p ()) + { + error ("a template cannot be defaulted"); + return false; + } + + if (DECL_CONSTRUCTOR_P (fn)) + { + if (FUNCTION_FIRST_USER_PARMTYPE (fn) == void_list_node) + kind = sfk_constructor; + else if (copy_fn_p (fn) > 0 + && (TREE_CHAIN (FUNCTION_FIRST_USER_PARMTYPE (fn)) + == void_list_node)) + kind = sfk_copy_constructor; + else if (move_fn_p (fn)) + kind = sfk_move_constructor; + } + else if (DECL_DESTRUCTOR_P (fn)) + kind = sfk_destructor; + else if (DECL_ASSIGNMENT_OPERATOR_P (fn) + && DECL_OVERLOADED_OPERATOR_IS (fn, NOP_EXPR)) + { + if (copy_fn_p (fn)) + kind = sfk_copy_assignment; + else if (move_fn_p (fn)) + kind = sfk_move_assignment; + } + else if (DECL_OVERLOADED_OPERATOR_CODE_RAW (fn) >= OVL_OP_EQ_EXPR + && DECL_OVERLOADED_OPERATOR_CODE_RAW (fn) <= OVL_OP_SPACESHIP_EXPR) + { + kind = sfk_comparison; + if (!early_check_defaulted_comparison (fn)) + return false; + } + + if (kind == sfk_none) + { + error ("%qD cannot be defaulted", fn); + return false; + } + else + { + for (tree t = FUNCTION_FIRST_USER_PARMTYPE (fn); + t && t != void_list_node; t = TREE_CHAIN (t)) + if (TREE_PURPOSE (t)) + { + error ("defaulted function %q+D with default argument", fn); + break; + } + + /* Avoid do_warn_unused_parameter warnings. */ + for (tree p = FUNCTION_FIRST_USER_PARM (fn); p; p = DECL_CHAIN (p)) + if (DECL_NAME (p)) + suppress_warning (p, OPT_Wunused_parameter); + + if (current_class_type && TYPE_BEING_DEFINED (current_class_type)) + /* Defer checking. */; + else if (!processing_template_decl) + defaulted_late_check (fn); + + return true; + } +} + +/* Add an implicit declaration to TYPE for the kind of function + indicated by SFK. Return the FUNCTION_DECL for the new implicit + declaration. */ + +tree +lazily_declare_fn (special_function_kind sfk, tree type) +{ + tree fn; + /* Whether or not the argument has a const reference type. */ + bool const_p = false; + + type = TYPE_MAIN_VARIANT (type); + + switch (sfk) + { + case sfk_constructor: + CLASSTYPE_LAZY_DEFAULT_CTOR (type) = 0; + break; + case sfk_copy_constructor: + const_p = TYPE_HAS_CONST_COPY_CTOR (type); + CLASSTYPE_LAZY_COPY_CTOR (type) = 0; + break; + case sfk_move_constructor: + CLASSTYPE_LAZY_MOVE_CTOR (type) = 0; + break; + case sfk_copy_assignment: + const_p = TYPE_HAS_CONST_COPY_ASSIGN (type); + CLASSTYPE_LAZY_COPY_ASSIGN (type) = 0; + break; + case sfk_move_assignment: + CLASSTYPE_LAZY_MOVE_ASSIGN (type) = 0; + break; + case sfk_destructor: + CLASSTYPE_LAZY_DESTRUCTOR (type) = 0; + break; + default: + gcc_unreachable (); + } + + /* Declare the function. */ + fn = implicitly_declare_fn (sfk, type, const_p, NULL, NULL); + + /* [class.copy]/8 If the class definition declares a move constructor or + move assignment operator, the implicitly declared copy constructor is + defined as deleted.... */ + if ((sfk == sfk_copy_assignment || sfk == sfk_copy_constructor) + && cxx_dialect >= cxx11) + { + if (classtype_has_move_assign_or_move_ctor_p (type, true)) + DECL_DELETED_FN (fn) = true; + else if (classtype_has_depr_implicit_copy (type)) + /* The implicit definition of a copy constructor as defaulted is + deprecated if the class has a user-declared copy assignment operator + or a user-declared destructor. The implicit definition of a copy + assignment operator as defaulted is deprecated if the class has a + user-declared copy constructor or a user-declared destructor (15.4, + 15.8). */ + TREE_DEPRECATED (fn) = true; + } + + /* Destructors and assignment operators may be virtual. */ + if (sfk == sfk_destructor + || sfk == sfk_move_assignment + || sfk == sfk_copy_assignment) + check_for_override (fn, type); + + /* Add it to the class */ + bool added = add_method (type, fn, false); + gcc_assert (added || errorcount); + + /* Add it to TYPE_FIELDS. */ + if (sfk == sfk_destructor + && DECL_VIRTUAL_P (fn)) + /* The ABI requires that a virtual destructor go at the end of the + vtable. */ + TYPE_FIELDS (type) = chainon (TYPE_FIELDS (type), fn); + else + { + DECL_CHAIN (fn) = TYPE_FIELDS (type); + TYPE_FIELDS (type) = fn; + } + /* Propagate TYPE_FIELDS. */ + fixup_type_variants (type); + + maybe_add_class_template_decl_list (type, fn, /*friend_p=*/0); + if (DECL_MAYBE_IN_CHARGE_CDTOR_P (fn)) + /* Create appropriate clones. */ + clone_cdtor (fn, /*update_methods=*/true); + + return fn; +} + +/* Given a FUNCTION_DECL FN and a chain LIST, skip as many elements of LIST + as there are artificial parms in FN. */ + +tree +skip_artificial_parms_for (const_tree fn, tree list) +{ + if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn)) + list = TREE_CHAIN (list); + else + return list; + + if (DECL_HAS_IN_CHARGE_PARM_P (fn)) + list = TREE_CHAIN (list); + if (DECL_HAS_VTT_PARM_P (fn)) + list = TREE_CHAIN (list); + return list; +} + +/* Given a FUNCTION_DECL FN and a chain LIST, return the number of + artificial parms in FN. */ + +int +num_artificial_parms_for (const_tree fn) +{ + int count = 0; + + if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn)) + count++; + else + return 0; + + if (DECL_HAS_IN_CHARGE_PARM_P (fn)) + count++; + if (DECL_HAS_VTT_PARM_P (fn)) + count++; + return count; +} + + +#include "gt-cp-method.h" |