diff options
Diffstat (limited to 'gcc/cp/semantics.c')
| -rw-r--r-- | gcc/cp/semantics.c | 522 |
1 files changed, 516 insertions, 6 deletions
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c index 6b741b3..6dec9f8 100644 --- a/gcc/cp/semantics.c +++ b/gcc/cp/semantics.c @@ -55,6 +55,7 @@ along with GCC; see the file COPYING3. If not see static tree maybe_convert_cond (tree); static tree finalize_nrv_r (tree *, int *, void *); +static tree capture_decltype (tree); /* Deferred Access Checking Overview @@ -1445,6 +1446,21 @@ finish_non_static_data_member (tree decl, tree object, tree qualifying_scope) return error_mark_node; } + + /* If decl is a field, object has a lambda type, and decl is not a member + of that type, then we have a reference to a member of 'this' from a + lambda inside a non-static member function, and we must get to decl + through the 'this' capture. If decl is not a member of that object, + either, then its access will still fail later. */ + if (LAMBDA_TYPE_P (TREE_TYPE (object)) + && !same_type_ignoring_top_level_qualifiers_p (DECL_CONTEXT (decl), + TREE_TYPE (object))) + object = cp_build_indirect_ref (lambda_expr_this_capture + (CLASSTYPE_LAMBDA_EXPR + (TREE_TYPE (object))), + /*errorstring=*/"", + /*complain=*/tf_warning_or_error); + if (current_class_ptr) TREE_USED (current_class_ptr) = 1; if (processing_template_decl && !qualifying_scope) @@ -2049,7 +2065,14 @@ finish_this_expr (void) if (current_class_ptr) { - result = current_class_ptr; + tree type = TREE_TYPE (current_class_ref); + + /* In a lambda expression, 'this' refers to the captured 'this'. */ + if (LAMBDA_TYPE_P (type)) + result = lambda_expr_this_capture (CLASSTYPE_LAMBDA_EXPR (type)); + else + result = current_class_ptr; + } else if (current_function_decl && DECL_STATIC_FUNCTION_P (current_function_decl)) @@ -2613,6 +2636,18 @@ baselink_for_fns (tree fns) return build_baselink (cl, cl, fns, /*optype=*/NULL_TREE); } +/* Returns true iff DECL is an automatic variable from a function outside + the current one. */ + +static bool +outer_automatic_var_p (tree decl) +{ + return ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL) + && DECL_FUNCTION_SCOPE_P (decl) + && !TREE_STATIC (decl) + && DECL_CONTEXT (decl) != current_function_decl); +} + /* ID_EXPRESSION is a representation of parsed, but unprocessed, id-expression. (See cp_parser_id_expression for details.) SCOPE, if non-NULL, is the type or namespace used to explicitly qualify @@ -2714,12 +2749,61 @@ finish_id_expression (tree id_expression, if (!scope && decl != error_mark_node) maybe_note_name_used_in_class (id_expression, decl); - /* Disallow uses of local variables from containing functions. */ - if (TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL) + /* Disallow uses of local variables from containing functions, except + within lambda-expressions. */ + if (outer_automatic_var_p (decl) + /* It's not a use (3.2) if we're in an unevaluated context. */ + && !cp_unevaluated_operand) { - tree context = decl_function_context (decl); - if (context != NULL_TREE && context != current_function_decl - && ! TREE_STATIC (decl)) + tree context = DECL_CONTEXT (decl); + tree containing_function = current_function_decl; + tree lambda_stack = NULL_TREE; + tree lambda_expr = NULL_TREE; + + /* Core issue 696: "[At the July 2009 meeting] the CWG expressed + support for an approach in which a reference to a local + [constant] automatic variable in a nested class or lambda body + would enter the expression as an rvalue, which would reduce + the complexity of the problem" + + FIXME update for final resolution of core issue 696. */ + if (DECL_INTEGRAL_CONSTANT_VAR_P (decl)) + return integral_constant_value (decl); + + /* If we are in a lambda function, we can move out until we hit + 1. the context, + 2. a non-lambda function, or + 3. a non-default capturing lambda function. */ + while (context != containing_function + && LAMBDA_FUNCTION_P (containing_function)) + { + lambda_expr = CLASSTYPE_LAMBDA_EXPR + (DECL_CONTEXT (containing_function)); + + if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda_expr) + == CPLD_NONE) + break; + + lambda_stack = tree_cons (NULL_TREE, + lambda_expr, + lambda_stack); + + containing_function + = decl_function_context (containing_function); + } + + if (context == containing_function) + { + decl = add_default_capture (lambda_stack, + /*id=*/DECL_NAME (decl), + /*initializer=*/decl); + } + else if (lambda_expr) + { + error ("%qD is not captured", decl); + return error_mark_node; + } + else { error (TREE_CODE (decl) == VAR_DECL ? "use of %<auto%> variable from containing function" @@ -4788,6 +4872,18 @@ finish_decltype_type (tree expr, bool id_expression_or_member_access_p) if (real_lvalue_p (expr)) type = build_reference_type (type); } + /* Within a lambda-expression: + + Every occurrence of decltype((x)) where x is a possibly + parenthesized id-expression that names an entity of + automatic storage duration is treated as if x were + transformed into an access to a corresponding data member + of the closure type that would have been declared if x + were a use of the denoted entity. */ + else if (outer_automatic_var_p (expr) + && current_function_decl + && LAMBDA_FUNCTION_P (current_function_decl)) + type = capture_decltype (expr); else { /* Otherwise, where T is the type of e, if e is an lvalue, @@ -4842,6 +4938,8 @@ classtype_has_nothrow_assign_or_copy_p (tree type, bool assign_p) it now. */ if (CLASSTYPE_LAZY_COPY_CTOR (type)) lazily_declare_fn (sfk_copy_constructor, type); + if (CLASSTYPE_LAZY_MOVE_CTOR (type)) + lazily_declare_fn (sfk_move_constructor, type); fns = CLASSTYPE_CONSTRUCTORS (type); } else @@ -5105,4 +5203,416 @@ float_const_decimal64_p (void) return 0; } +/* Constructor for a lambda expression. */ + +tree +build_lambda_expr (void) +{ + tree lambda = make_node (LAMBDA_EXPR); + LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda) = CPLD_NONE; + LAMBDA_EXPR_CAPTURE_LIST (lambda) = NULL_TREE; + LAMBDA_EXPR_THIS_CAPTURE (lambda) = NULL_TREE; + LAMBDA_EXPR_RETURN_TYPE (lambda) = NULL_TREE; + LAMBDA_EXPR_MUTABLE_P (lambda) = false; + return lambda; +} + +/* Create the closure object for a LAMBDA_EXPR. */ + +tree +build_lambda_object (tree lambda_expr) +{ + /* Build aggregate constructor call. + - cp_parser_braced_list + - cp_parser_functional_cast */ + VEC(constructor_elt,gc) *elts = NULL; + tree node, expr, type; + location_t saved_loc; + + if (processing_template_decl) + return lambda_expr; + + /* Make sure any error messages refer to the lambda-introducer. */ + saved_loc = input_location; + input_location = LAMBDA_EXPR_LOCATION (lambda_expr); + + for (node = LAMBDA_EXPR_CAPTURE_LIST (lambda_expr); + node; + node = TREE_CHAIN (node)) + { + tree field = TREE_PURPOSE (node); + tree val = TREE_VALUE (node); + + /* Mere mortals can't copy arrays with aggregate initialization, so + do some magic to make it work here. */ + if (TREE_CODE (TREE_TYPE (field)) == ARRAY_TYPE) + val = build_array_copy (val); + + CONSTRUCTOR_APPEND_ELT (elts, DECL_NAME (field), val); + } + + expr = build_constructor (init_list_type_node, elts); + CONSTRUCTOR_IS_DIRECT_INIT (expr) = 1; + + /* N2927: "[The closure] class type is not an aggregate." + But we briefly treat it as an aggregate to make this simpler. */ + type = TREE_TYPE (lambda_expr); + CLASSTYPE_NON_AGGREGATE (type) = 0; + expr = finish_compound_literal (type, expr); + CLASSTYPE_NON_AGGREGATE (type) = 1; + + input_location = saved_loc; + return expr; +} + +/* Return an initialized RECORD_TYPE for LAMBDA. + LAMBDA must have its explicit captures already. */ + +tree +begin_lambda_type (tree lambda) +{ + tree type; + + { + /* Unique name. This is just like an unnamed class, but we cannot use + make_anon_name because of certain checks against TYPE_ANONYMOUS_P. */ + tree name; + name = make_lambda_name (); + + /* Create the new RECORD_TYPE for this lambda. */ + type = xref_tag (/*tag_code=*/record_type, + name, + /*scope=*/ts_within_enclosing_non_class, + /*template_header_p=*/false); + } + + /* Designate it as a struct so that we can use aggregate initialization. */ + CLASSTYPE_DECLARED_CLASS (type) = false; + + /* Clear base types. */ + xref_basetypes (type, /*bases=*/NULL_TREE); + + /* Start the class. */ + type = begin_class_definition (type, /*attributes=*/NULL_TREE); + + /* Cross-reference the expression and the type. */ + TREE_TYPE (lambda) = type; + CLASSTYPE_LAMBDA_EXPR (type) = lambda; + + return type; +} + +/* Returns the type to use for the return type of the operator() of a + closure class. */ + +tree +lambda_return_type (tree expr) +{ + tree type; + if (type_dependent_expression_p (expr)) + { + type = cxx_make_type (DECLTYPE_TYPE); + DECLTYPE_TYPE_EXPR (type) = expr; + DECLTYPE_FOR_LAMBDA_RETURN (type) = true; + SET_TYPE_STRUCTURAL_EQUALITY (type); + } + else + type = type_decays_to (unlowered_expr_type (expr)); + return type; +} + +/* Given a LAMBDA_EXPR or closure type LAMBDA, return the op() of the + closure type. */ + +tree +lambda_function (tree lambda) +{ + tree type; + if (TREE_CODE (lambda) == LAMBDA_EXPR) + type = TREE_TYPE (lambda); + else + type = lambda; + gcc_assert (LAMBDA_TYPE_P (type)); + /* Don't let debug_tree cause instantiation. */ + if (CLASSTYPE_TEMPLATE_INSTANTIATION (type) && !COMPLETE_TYPE_P (type)) + return NULL_TREE; + lambda = lookup_member (type, ansi_opname (CALL_EXPR), + /*protect=*/0, /*want_type=*/false); + if (lambda) + lambda = BASELINK_FUNCTIONS (lambda); + return lambda; +} + +/* Returns the type to use for the FIELD_DECL corresponding to the + capture of EXPR. + The caller should add REFERENCE_TYPE for capture by reference. */ + +tree +lambda_capture_field_type (tree expr) +{ + tree type; + if (type_dependent_expression_p (expr)) + { + type = cxx_make_type (DECLTYPE_TYPE); + DECLTYPE_TYPE_EXPR (type) = expr; + DECLTYPE_FOR_LAMBDA_CAPTURE (type) = true; + SET_TYPE_STRUCTURAL_EQUALITY (type); + } + else + type = non_reference (unlowered_expr_type (expr)); + return type; +} + +/* Recompute the return type for LAMBDA with body of the form: + { return EXPR ; } */ + +void +apply_lambda_return_type (tree lambda, tree return_type) +{ + tree fco = lambda_function (lambda); + tree result; + + LAMBDA_EXPR_RETURN_TYPE (lambda) = return_type; + + /* If we got a DECLTYPE_TYPE, don't stick it in the function yet, + it would interfere with instantiating the closure type. */ + if (dependent_type_p (return_type)) + return; + if (return_type == error_mark_node) + return; + + /* TREE_TYPE (FUNCTION_DECL) == METHOD_TYPE + TREE_TYPE (METHOD_TYPE) == return-type */ + TREE_TYPE (TREE_TYPE (fco)) = return_type; + + result = DECL_RESULT (fco); + if (result == NULL_TREE) + return; + + /* We already have a DECL_RESULT from start_preparsed_function. + Now we need to redo the work it and allocate_struct_function + did to reflect the new type. */ + result = build_decl (input_location, RESULT_DECL, NULL_TREE, + TYPE_MAIN_VARIANT (return_type)); + DECL_ARTIFICIAL (result) = 1; + DECL_IGNORED_P (result) = 1; + cp_apply_type_quals_to_decl (cp_type_quals (return_type), + result); + + DECL_RESULT (fco) = result; + + if (!processing_template_decl && aggregate_value_p (result, fco)) + { +#ifdef PCC_STATIC_STRUCT_RETURN + cfun->returns_pcc_struct = 1; +#endif + cfun->returns_struct = 1; + } + +} + +/* DECL is a local variable or parameter from the surrounding scope of a + lambda-expression. Returns the decltype for a use of the capture field + for DECL even if it hasn't been captured yet. */ + +static tree +capture_decltype (tree decl) +{ + tree lam = CLASSTYPE_LAMBDA_EXPR (DECL_CONTEXT (current_function_decl)); + /* FIXME do lookup instead of list walk? */ + tree cap = value_member (decl, LAMBDA_EXPR_CAPTURE_LIST (lam)); + tree type; + + if (cap) + type = TREE_TYPE (TREE_PURPOSE (cap)); + else + switch (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lam)) + { + case CPLD_NONE: + error ("%qD is not captured", decl); + return error_mark_node; + + case CPLD_COPY: + type = TREE_TYPE (decl); + if (TREE_CODE (type) == REFERENCE_TYPE + && TREE_CODE (TREE_TYPE (type)) != FUNCTION_TYPE) + type = TREE_TYPE (type); + break; + + case CPLD_REFERENCE: + type = TREE_TYPE (decl); + if (TREE_CODE (type) != REFERENCE_TYPE) + type = build_reference_type (TREE_TYPE (decl)); + break; + + default: + gcc_unreachable (); + } + + if (TREE_CODE (type) != REFERENCE_TYPE) + { + if (!LAMBDA_EXPR_MUTABLE_P (lam)) + type = cp_build_qualified_type (type, (TYPE_QUALS (type) + |TYPE_QUAL_CONST)); + type = build_reference_type (type); + } + return type; +} + +/* From an ID and INITIALIZER, create a capture (by reference if + BY_REFERENCE_P is true), add it to the capture-list for LAMBDA, + and return it. */ + +tree +add_capture (tree lambda, tree id, tree initializer, bool by_reference_p) +{ + tree type; + tree member; + + type = lambda_capture_field_type (initializer); + if (by_reference_p) + { + type = build_reference_type (type); + if (!real_lvalue_p (initializer)) + error ("cannot capture %qE by reference", initializer); + } + + /* Make member variable. */ + member = build_lang_decl (FIELD_DECL, id, type); + + /* Add it to the appropriate closure class. */ + finish_member_declaration (member); + + LAMBDA_EXPR_CAPTURE_LIST (lambda) + = tree_cons (member, initializer, LAMBDA_EXPR_CAPTURE_LIST (lambda)); + + if (id == get_identifier ("__this")) + { + if (LAMBDA_EXPR_CAPTURES_THIS_P (lambda)) + error ("already captured %<this%> in lambda expression"); + LAMBDA_EXPR_THIS_CAPTURE (lambda) = member; + } + + return member; +} + +/* Similar to add_capture, except this works on a stack of nested lambdas. + BY_REFERENCE_P in this case is derived from the default capture mode. + Returns the capture for the lambda at the bottom of the stack. */ + +tree +add_default_capture (tree lambda_stack, tree id, tree initializer) +{ + bool this_capture_p = (id == get_identifier ("__this")); + + tree member = NULL_TREE; + + tree saved_class_type = current_class_type; + + tree node; + + for (node = lambda_stack; + node; + node = TREE_CHAIN (node)) + { + tree lambda = TREE_VALUE (node); + + current_class_type = TREE_TYPE (lambda); + member = add_capture (lambda, + id, + initializer, + /*by_reference_p=*/ + (!this_capture_p + && (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda) + == CPLD_REFERENCE))); + + { + /* Have to get the old value of current_class_ref. */ + tree object = cp_build_indirect_ref (DECL_ARGUMENTS + (lambda_function (lambda)), + /*errorstring=*/"", + /*complain=*/tf_warning_or_error); + initializer = finish_non_static_data_member + (member, object, /*qualifying_scope=*/NULL_TREE); + } + } + + current_class_type = saved_class_type; + + return member; + +} + +/* Return the capture pertaining to a use of 'this' in LAMBDA, in the form of an + INDIRECT_REF, possibly adding it through default capturing. */ + +tree +lambda_expr_this_capture (tree lambda) +{ + tree result; + + tree this_capture = LAMBDA_EXPR_THIS_CAPTURE (lambda); + + /* Try to default capture 'this' if we can. */ + if (!this_capture + && LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda) != CPLD_NONE) + { + tree containing_function = TYPE_CONTEXT (TREE_TYPE (lambda)); + tree lambda_stack = tree_cons (NULL_TREE, lambda, NULL_TREE); + + /* If we are in a lambda function, we can move out until we hit: + 1. a non-lambda function, + 2. a lambda function capturing 'this', or + 3. a non-default capturing lambda function. */ + while (LAMBDA_FUNCTION_P (containing_function)) + { + tree lambda + = CLASSTYPE_LAMBDA_EXPR (DECL_CONTEXT (containing_function)); + + if (LAMBDA_EXPR_THIS_CAPTURE (lambda) + || LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda) == CPLD_NONE) + break; + + lambda_stack = tree_cons (NULL_TREE, + lambda, + lambda_stack); + + containing_function = decl_function_context (containing_function); + } + + if (DECL_NONSTATIC_MEMBER_FUNCTION_P (containing_function)) + { + this_capture = add_default_capture (lambda_stack, + /*id=*/get_identifier ("__this"), + /* First parameter is 'this'. */ + /*initializer=*/DECL_ARGUMENTS + (containing_function)); + } + + } + + if (!this_capture) + { + error ("%<this%> was not captured for this lambda function"); + result = error_mark_node; + } + else + { + /* To make sure that current_class_ref is for the lambda. */ + gcc_assert (TYPE_MAIN_VARIANT (TREE_TYPE (current_class_ref)) == TREE_TYPE (lambda)); + + result = finish_non_static_data_member (this_capture, + current_class_ref, + /*qualifying_scope=*/NULL_TREE); + + /* If 'this' is captured, each use of 'this' is transformed into an + access to the corresponding unnamed data member of the closure + type cast (_expr.cast_ 5.4) to the type of 'this'. [ The cast + ensures that the transformed expression is an rvalue. ] */ + result = rvalue (result); + } + + return result; +} + #include "gt-cp-semantics.h" |