/* The next conversion in the chain. Since the conversions are
arranged from outermost to innermost, the NEXT conversion will
actually be performed before this conversion. This variant is
- used only when KIND is neither ck_identity nor ck_ambig. */
+ used only when KIND is neither ck_identity, ck_ambig nor
+ ck_list. Please use the next_conversion function instead
+ of using this field directly. */
conversion *next;
/* The expression at the beginning of the conversion chain. This
variant is used only if KIND is ck_identity or ck_ambig. */
tree expr;
- /* The array of conversions for an initializer_list. */
+ /* The array of conversions for an initializer_list, so this
+ variant is used only when KIN D is ck_list. */
conversion **list;
} u;
/* The function candidate corresponding to this conversion
static conversion *reference_binding (tree, tree, tree, bool, int);
static conversion *build_conv (conversion_kind, tree, conversion *);
static conversion *build_list_conv (tree, tree, int);
+static conversion *next_conversion (conversion *);
static bool is_subseq (conversion *, conversion *);
static conversion *maybe_handle_ref_bind (conversion **);
static void maybe_handle_implicit_object (conversion **);
{
/* Core issue 903 says only literal 0 is a null pointer constant. */
if (cxx_dialect < cxx0x)
- {
- t = integral_constant_value (t);
- STRIP_NOPS (t);
- }
+ t = integral_constant_value (t);
+ STRIP_NOPS (t);
if (integer_zerop (t) && !TREE_OVERFLOW (t))
return true;
}
return t;
}
+/* Return the next conversion of the conversion chain (if applicable),
+ or NULL otherwise. Please use this function instead of directly
+ accessing fields of struct conversion. */
+
+static conversion *
+next_conversion (conversion *conv)
+{
+ if (conv == NULL
+ || conv->kind == ck_identity
+ || conv->kind == ck_ambig
+ || conv->kind == ck_list)
+ return NULL;
+ return conv->u.next;
+}
+
/* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
is a valid aggregate initializer for array type ATYPE. */
build_user_type_conversion_1 (tree totype, tree expr, int flags)
{
struct z_candidate *candidates, *cand;
- tree fromtype = TREE_TYPE (expr);
+ tree fromtype;
tree ctors = NULL_TREE;
tree conv_fns = NULL_TREE;
conversion *conv = NULL;
bool any_viable_p;
int convflags;
+ if (!expr)
+ return NULL;
+
+ fromtype = TREE_TYPE (expr);
+
/* We represent conversion within a hierarchy using RVALUE_CONV and
BASE_CONV, as specified by [over.best.ics]; these become plain
constructor calls, as specified in [dcl.init]. */
return error_mark_node;
}
+ if (flag_tm)
+ tm_malloc_replacement (fn);
+
/* If this function was found without using argument dependent
lookup, then we want to ignore any undeclared friend
functions. */
}
/* Issue warnings if "false" is converted to a NULL pointer */
- else if (expr == boolean_false_node && TYPE_PTR_P (totype))
+ else if (TREE_CODE (TREE_TYPE (expr)) == BOOLEAN_TYPE
+ && TYPE_PTR_P (totype))
{
if (fn)
warning_at (input_location, OPT_Wconversion_null,
&& BRACE_ENCLOSED_INITIALIZER_P (CONSTRUCTOR_ELT (expr, 0)->value))
permerror (input_location, "too many braces around initializer for %qT", totype);
- for (; t; t = t->u.next)
+ for (; t ; t = next_conversion (t))
{
if (t->kind == ck_user && t->cand->reason)
{
current_in_charge_parm, integer_zero_node),
current_vtt_parm,
vtt);
- gcc_assert (BINFO_SUBVTT_INDEX (binfo));
- sub_vtt = fold_build_pointer_plus (vtt, BINFO_SUBVTT_INDEX (binfo));
+ if (BINFO_SUBVTT_INDEX (binfo))
+ sub_vtt = fold_build_pointer_plus (vtt, BINFO_SUBVTT_INDEX (binfo));
+ else
+ sub_vtt = vtt;
if (args == NULL)
{
&& CONSTRUCTOR_IS_DIRECT_INIT (VEC_index (tree, *args, 0)))
{
tree init_list = VEC_index (tree, *args, 0);
+ tree init = NULL_TREE;
gcc_assert (VEC_length (tree, *args) == 1
&& !(flags & LOOKUP_ONLYCONVERTING));
if (CONSTRUCTOR_NELTS (init_list) == 0
&& TYPE_HAS_DEFAULT_CONSTRUCTOR (basetype)
&& !processing_template_decl)
+ init = build_value_init (basetype, complain);
+
+ /* If BASETYPE is an aggregate, we need to do aggregate
+ initialization. */
+ else if (CP_AGGREGATE_TYPE_P (basetype))
+ init = digest_init (basetype, init_list, complain);
+
+ if (init)
{
- tree ob, init = build_value_init (basetype, complain);
+ tree ob;
if (integer_zerop (instance_ptr))
return get_target_expr_sfinae (init, complain);
ob = build_fold_indirect_ref (instance_ptr);
return init;
}
+ /* Otherwise go ahead with overload resolution. */
add_list_candidates (fns, first_mem_arg, init_list,
basetype, explicit_targs, template_only,
conversion_path, access_binfo, flags, &candidates);
if (winner)
return winner;
+ /* DR 495 moved this tiebreaker above the template ones. */
+ /* or, if not that,
+ the context is an initialization by user-defined conversion (see
+ _dcl.init_ and _over.match.user_) and the standard conversion
+ sequence from the return type of F1 to the destination type (i.e.,
+ the type of the entity being initialized) is a better conversion
+ sequence than the standard conversion sequence from the return type
+ of F2 to the destination type. */
+
+ if (cand1->second_conv)
+ {
+ winner = compare_ics (cand1->second_conv, cand2->second_conv);
+ if (winner)
+ return winner;
+ }
+
/* or, if not that,
F1 is a non-template function and F2 is a template function
specialization. */
return winner;
}
- /* or, if not that,
- the context is an initialization by user-defined conversion (see
- _dcl.init_ and _over.match.user_) and the standard conversion
- sequence from the return type of F1 to the destination type (i.e.,
- the type of the entity being initialized) is a better conversion
- sequence than the standard conversion sequence from the return type
- of F2 to the destination type. */
-
- if (cand1->second_conv)
- {
- winner = compare_ics (cand1->second_conv, cand2->second_conv);
- if (winner)
- return winner;
- }
-
/* Check whether we can discard a builtin candidate, either because we
have two identical ones or matching builtin and non-builtin candidates.
}
expr = error_mark_node;
}
- else if (processing_template_decl
- /* As a kludge, we always perform conversions between scalar
- types, as IMPLICIT_CONV_EXPR confuses c_finish_omp_for. */
- && !(SCALAR_TYPE_P (type) && SCALAR_TYPE_P (TREE_TYPE (expr))))
+ else if (processing_template_decl && conv->kind != ck_identity)
{
/* In a template, we are only concerned about determining the
type of non-dependent expressions, so we do not have to
return expr;
}
+/* When initializing a reference that lasts longer than a full-expression,
+ this special rule applies:
+
+ [class.temporary]
+
+ The temporary to which the reference is bound or the temporary
+ that is the complete object to which the reference is bound
+ persists for the lifetime of the reference.
+
+ The temporaries created during the evaluation of the expression
+ initializing the reference, except the temporary to which the
+ reference is bound, are destroyed at the end of the
+ full-expression in which they are created.
+
+ In that case, we store the converted expression into a new
+ VAR_DECL in a new scope.
+
+ However, we want to be careful not to create temporaries when
+ they are not required. For example, given:
+
+ struct B {};
+ struct D : public B {};
+ D f();
+ const B& b = f();
+
+ there is no need to copy the return value from "f"; we can just
+ extend its lifetime. Similarly, given:
+
+ struct S {};
+ struct T { operator S(); };
+ T t;
+ const S& s = t;
+
+ we can extend the lifetime of the return value of the conversion
+ operator.
+
+ The next several functions are involved in this lifetime extension. */
+
/* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
is being bound to a temporary. Create and return a new VAR_DECL
with the indicated TYPE; this variable will store the value to
if (TREE_STATIC (decl))
{
/* Namespace-scope or local static; give it a mangled name. */
+ /* FIXME share comdat with decl? */
tree name;
TREE_STATIC (var) = 1;
cleanup for the new variable is returned through CLEANUP, and the
code to initialize the new variable is returned through INITP. */
-tree
-set_up_extended_ref_temp (tree decl, tree expr, tree *cleanup, tree *initp)
+static tree
+set_up_extended_ref_temp (tree decl, tree expr, VEC(tree,gc) **cleanups,
+ tree *initp)
{
tree init;
tree type;
if (TREE_CODE (expr) != TARGET_EXPR)
expr = get_target_expr (expr);
+ if (TREE_CODE (decl) == FIELD_DECL
+ && extra_warnings && !TREE_NO_WARNING (decl))
+ {
+ warning (OPT_Wextra, "a temporary bound to %qD only persists "
+ "until the constructor exits", decl);
+ TREE_NO_WARNING (decl) = true;
+ }
+
+ /* Recursively extend temps in this initializer. */
+ TARGET_EXPR_INITIAL (expr)
+ = extend_ref_init_temps (decl, TARGET_EXPR_INITIAL (expr), cleanups);
+
/* If the initializer is constant, put it in DECL_INITIAL so we get
static initialization and use in constant expressions. */
init = maybe_constant_init (expr);
if (TREE_STATIC (var))
init = add_stmt_to_compound (init, register_dtor_fn (var));
else
- *cleanup = cxx_maybe_build_cleanup (var, tf_warning_or_error);
+ {
+ tree cleanup = cxx_maybe_build_cleanup (var, tf_warning_or_error);
+ if (cleanup)
+ VEC_safe_push (tree, gc, *cleanups, cleanup);
+ }
/* We must be careful to destroy the temporary only
after its initialization has taken place. If the
}
/* Convert EXPR to the indicated reference TYPE, in a way suitable for
- initializing a variable of that TYPE. If DECL is non-NULL, it is
- the VAR_DECL being initialized with the EXPR. (In that case, the
- type of DECL will be TYPE.) If DECL is non-NULL, then CLEANUP must
- also be non-NULL, and with *CLEANUP initialized to NULL. Upon
- return, if *CLEANUP is no longer NULL, it will be an expression
- that should be pushed as a cleanup after the returned expression
- is used to initialize DECL.
-
- Return the converted expression. */
+ initializing a variable of that TYPE. */
tree
-initialize_reference (tree type, tree expr, tree decl, tree *cleanup,
+initialize_reference (tree type, tree expr,
int flags, tsubst_flags_t complain)
{
conversion *conv;
return error_mark_node;
}
- /* If DECL is non-NULL, then this special rule applies:
-
- [class.temporary]
-
- The temporary to which the reference is bound or the temporary
- that is the complete object to which the reference is bound
- persists for the lifetime of the reference.
+ gcc_assert (conv->kind == ck_ref_bind);
- The temporaries created during the evaluation of the expression
- initializing the reference, except the temporary to which the
- reference is bound, are destroyed at the end of the
- full-expression in which they are created.
+ /* Perform the conversion. */
+ expr = convert_like (conv, expr, complain);
- In that case, we store the converted expression into a new
- VAR_DECL in a new scope.
+ /* Free all the conversions we allocated. */
+ obstack_free (&conversion_obstack, p);
- However, we want to be careful not to create temporaries when
- they are not required. For example, given:
+ return expr;
+}
- struct B {};
- struct D : public B {};
- D f();
- const B& b = f();
+/* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
+ which is bound either to a reference or a std::initializer_list. */
- there is no need to copy the return value from "f"; we can just
- extend its lifetime. Similarly, given:
+static tree
+extend_ref_init_temps_1 (tree decl, tree init, VEC(tree,gc) **cleanups)
+{
+ tree sub = init;
+ tree *p;
+ STRIP_NOPS (sub);
+ if (TREE_CODE (sub) != ADDR_EXPR)
+ return init;
+ /* Deal with binding to a subobject. */
+ for (p = &TREE_OPERAND (sub, 0); TREE_CODE (*p) == COMPONENT_REF; )
+ p = &TREE_OPERAND (*p, 0);
+ if (TREE_CODE (*p) == TARGET_EXPR)
+ {
+ tree subinit = NULL_TREE;
+ *p = set_up_extended_ref_temp (decl, *p, cleanups, &subinit);
+ if (subinit)
+ init = build2 (COMPOUND_EXPR, TREE_TYPE (init), subinit, init);
+ }
+ return init;
+}
- struct S {};
- struct T { operator S(); };
- T t;
- const S& s = t;
+/* INIT is part of the initializer for DECL. If there are any
+ reference or initializer lists being initialized, extend their
+ lifetime to match that of DECL. */
- we can extend the lifetime of the return value of the conversion
- operator. */
- gcc_assert (conv->kind == ck_ref_bind);
- if (decl)
+tree
+extend_ref_init_temps (tree decl, tree init, VEC(tree,gc) **cleanups)
+{
+ tree type = TREE_TYPE (init);
+ if (processing_template_decl)
+ return init;
+ if (TREE_CODE (type) == REFERENCE_TYPE)
+ init = extend_ref_init_temps_1 (decl, init, cleanups);
+ else if (is_std_init_list (type))
{
- tree var;
- tree base_conv_type;
-
- gcc_assert (complain == tf_warning_or_error);
-
- /* Skip over the REF_BIND. */
- conv = conv->u.next;
- /* If the next conversion is a BASE_CONV, skip that too -- but
- remember that the conversion was required. */
- if (conv->kind == ck_base)
- {
- base_conv_type = conv->type;
- conv = conv->u.next;
- }
- else
- base_conv_type = NULL_TREE;
- /* Perform the remainder of the conversion. */
- expr = convert_like_real (conv, expr,
- /*fn=*/NULL_TREE, /*argnum=*/0,
- /*inner=*/-1,
- /*issue_conversion_warnings=*/true,
- /*c_cast_p=*/false,
- complain);
- if (error_operand_p (expr))
- expr = error_mark_node;
- else
+ /* The temporary array underlying a std::initializer_list
+ is handled like a reference temporary. */
+ tree ctor = init;
+ if (TREE_CODE (ctor) == TARGET_EXPR)
+ ctor = TARGET_EXPR_INITIAL (ctor);
+ if (TREE_CODE (ctor) == CONSTRUCTOR)
{
- if (!lvalue_or_rvalue_with_address_p (expr))
- {
- tree init;
- var = set_up_extended_ref_temp (decl, expr, cleanup, &init);
- /* Use its address to initialize the reference variable. */
- expr = build_address (var);
- if (base_conv_type)
- expr = convert_to_base (expr,
- build_pointer_type (base_conv_type),
- /*check_access=*/true,
- /*nonnull=*/true, complain);
- if (init)
- expr = build2 (COMPOUND_EXPR, TREE_TYPE (expr), init, expr);
- }
- else
- /* Take the address of EXPR. */
- expr = cp_build_addr_expr (expr, complain);
- /* If a BASE_CONV was required, perform it now. */
- if (base_conv_type)
- expr = (perform_implicit_conversion
- (build_pointer_type (base_conv_type), expr,
- complain));
- expr = build_nop (type, expr);
+ tree array = CONSTRUCTOR_ELT (ctor, 0)->value;
+ array = extend_ref_init_temps_1 (decl, array, cleanups);
+ CONSTRUCTOR_ELT (ctor, 0)->value = array;
}
}
- else
- /* Perform the conversion. */
- expr = convert_like (conv, expr, complain);
-
- /* Free all the conversions we allocated. */
- obstack_free (&conversion_obstack, p);
+ else if (TREE_CODE (init) == CONSTRUCTOR)
+ {
+ unsigned i;
+ constructor_elt *p;
+ VEC(constructor_elt,gc) *elts = CONSTRUCTOR_ELTS (init);
+ FOR_EACH_VEC_ELT (constructor_elt, elts, i, p)
+ p->value = extend_ref_init_temps (decl, p->value, cleanups);
+ }
- return expr;
+ return init;
}
/* Returns true iff TYPE is some variant of std::initializer_list. */
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