tree
lambda_return_type (tree expr)
{
if (expr == NULL_TREE)
return void_type_node;
if (type_unknown_p (expr)
|| BRACE_ENCLOSED_INITIALIZER_P (expr))
{
cxx_incomplete_type_error (expr, TREE_TYPE (expr));
return void_type_node;
}
gcc_checking_assert (!type_dependent_expression_p (expr));
return cv_unqualified (type_decays_to (unlowered_expr_type (expr)));
}
tree
convert_to_void (tree expr, const char *implicit, tsubst_flags_t complain)
{
if (expr == error_mark_node
|| TREE_TYPE (expr) == error_mark_node)
return error_mark_node;
if (!TREE_TYPE (expr))
return expr;
if (invalid_nonstatic_memfn_p (expr, complain))
return error_mark_node;
if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR)
{
if (complain & tf_error)
error ("pseudo-destructor is not called");
return error_mark_node;
}
if (VOID_TYPE_P (TREE_TYPE (expr)))
return expr;
switch (TREE_CODE (expr))
{
case COND_EXPR:
{
/* The two parts of a cond expr might be separate lvalues. */
tree op1 = TREE_OPERAND (expr,1);
tree op2 = TREE_OPERAND (expr,2);
tree new_op1 = convert_to_void
(op1, (implicit && !TREE_SIDE_EFFECTS (op2)
? "second operand of conditional" : NULL), complain);
tree new_op2 = convert_to_void
(op2, (implicit && !TREE_SIDE_EFFECTS (op1)
? "third operand of conditional" : NULL), complain);
expr = build3 (COND_EXPR, TREE_TYPE (new_op1),
TREE_OPERAND (expr, 0), new_op1, new_op2);
break;
}
case COMPOUND_EXPR:
{
/* The second part of a compound expr contains the value. */
tree op1 = TREE_OPERAND (expr,1);
tree new_op1 = convert_to_void
(op1, (implicit && !TREE_NO_WARNING (expr)
? "right-hand operand of comma" : NULL), complain);
if (new_op1 != op1)
{
tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1),
TREE_OPERAND (expr, 0), new_op1);
expr = t;
}
break;
}
case NON_LVALUE_EXPR:
case NOP_EXPR:
/* These have already decayed to rvalue. */
break;
case CALL_EXPR: /* We have a special meaning for volatile void fn(). */
break;
case INDIRECT_REF:
{
tree type = TREE_TYPE (expr);
int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0)))
== REFERENCE_TYPE;
int is_volatile = TYPE_VOLATILE (type);
int is_complete = COMPLETE_TYPE_P (complete_type (type));
/* Can't load the value if we don't know the type. */
if (is_volatile && !is_complete)
{
if (complain & tf_warning)
warning (0, "object of incomplete type %qT will not be accessed in %s",
type, implicit ? implicit : "void context");
}
/* Don't load the value if this is an implicit dereference, or if
the type needs to be handled by ctors/dtors. */
else if (is_volatile && (is_reference || TREE_ADDRESSABLE (type)))
{
if (complain & tf_warning)
warning (0, "object of type %qT will not be accessed in %s",
TREE_TYPE (TREE_OPERAND (expr, 0)),
implicit ? implicit : "void context");
}
if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type))
expr = TREE_OPERAND (expr, 0);
break;
}
case VAR_DECL:
{
/* External variables might be incomplete. */
tree type = TREE_TYPE (expr);
int is_complete = COMPLETE_TYPE_P (complete_type (type));
if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning))
warning (0, "object %qE of incomplete type %qT will not be accessed in %s",
expr, type, implicit ? implicit : "void context");
break;
}
case TARGET_EXPR:
/* Don't bother with the temporary object returned from a function if
we don't use it and don't need to destroy it. We'll still
allocate space for it in expand_call or declare_return_variable,
but we don't need to track it through all the tree phases. */
if (TARGET_EXPR_IMPLICIT_P (expr)
&& TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr)))
{
tree init = TARGET_EXPR_INITIAL (expr);
if (TREE_CODE (init) == AGGR_INIT_EXPR
&& !AGGR_INIT_VIA_CTOR_P (init))
{
tree fn = AGGR_INIT_EXPR_FN (init);
expr = build_call_array (TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))),
fn,
aggr_init_expr_nargs (init),
AGGR_INIT_EXPR_ARGP (init));
}
}
break;
default:;
}
{
tree probe = expr;
if (TREE_CODE (probe) == ADDR_EXPR)
probe = TREE_OPERAND (expr, 0);
if (type_unknown_p (probe))
{
/* [over.over] enumerates the places where we can take the address
of an overloaded function, and this is not one of them. */
if (complain & tf_error)
error ("%s cannot resolve address of overloaded function",
implicit ? implicit : "void cast");
else
return error_mark_node;
expr = void_zero_node;
}
else if (implicit && probe == expr && is_overloaded_fn (probe))
{
/* Only warn when there is no &. */
if (complain & tf_warning)
warning (OPT_Waddress, "%s is a reference, not call, to function %qE",
implicit, expr);
if (TREE_CODE (expr) == COMPONENT_REF)
expr = TREE_OPERAND (expr, 0);
}
}
if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr)))
{
if (implicit
&& warn_unused_value
&& !TREE_NO_WARNING (expr)
&& !processing_template_decl)
{
/* The middle end does not warn about expressions that have
been explicitly cast to void, so we must do so here. */
if (!TREE_SIDE_EFFECTS (expr)) {
if (complain & tf_warning)
warning (OPT_Wunused_value, "%s has no effect", implicit);
}
else
{
tree e;
enum tree_code code;
enum tree_code_class tclass;
e = expr;
/* We might like to warn about (say) "(int) f()", as the
cast has no effect, but the compiler itself will
generate implicit conversions under some
circumstances. (For example a block copy will be
turned into a call to "__builtin_memcpy", with a
conversion of the return value to an appropriate
type.) So, to avoid false positives, we strip
conversions. Do not use STRIP_NOPs because it will
not strip conversions to "void", as that is not a
mode-preserving conversion. */
while (TREE_CODE (e) == NOP_EXPR)
e = TREE_OPERAND (e, 0);
code = TREE_CODE (e);
tclass = TREE_CODE_CLASS (code);
if ((tclass == tcc_comparison
|| tclass == tcc_unary
|| (tclass == tcc_binary
&& !(code == MODIFY_EXPR
|| code == INIT_EXPR
|| code == PREDECREMENT_EXPR
|| code == PREINCREMENT_EXPR
|| code == POSTDECREMENT_EXPR
|| code == POSTINCREMENT_EXPR)))
&& (complain & tf_warning))
warning (OPT_Wunused_value, "value computed is not used");
}
}
expr = build1 (CONVERT_EXPR, void_type_node, expr);
}
if (! TREE_SIDE_EFFECTS (expr))
expr = void_zero_node;
return expr;
}
static tree
cp_convert_to_pointer (tree type, tree expr)
{
tree intype = TREE_TYPE (expr);
enum tree_code form;
tree rval;
if (intype == error_mark_node)
return error_mark_node;
if (MAYBE_CLASS_TYPE_P (intype))
{
intype = complete_type (intype);
if (!COMPLETE_TYPE_P (intype))
{
error ("can't convert from incomplete type %qT to %qT",
intype, type);
return error_mark_node;
}
rval = build_type_conversion (type, expr);
if (rval)
{
if (rval == error_mark_node)
error ("conversion of %qE from %qT to %qT is ambiguous",
expr, intype, type);
return rval;
}
}
/* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */
if (TREE_CODE (type) == POINTER_TYPE
&& (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
|| VOID_TYPE_P (TREE_TYPE (type))))
{
if (TYPE_PTRMEMFUNC_P (intype)
|| TREE_CODE (intype) == METHOD_TYPE)
return convert_member_func_to_ptr (type, expr);
if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE)
return build_nop (type, expr);
intype = TREE_TYPE (expr);
}
if (expr == error_mark_node)
return error_mark_node;
form = TREE_CODE (intype);
if (POINTER_TYPE_P (intype))
{
intype = TYPE_MAIN_VARIANT (intype);
if (TYPE_MAIN_VARIANT (type) != intype
&& TREE_CODE (type) == POINTER_TYPE
&& TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
&& MAYBE_CLASS_TYPE_P (TREE_TYPE (type))
&& MAYBE_CLASS_TYPE_P (TREE_TYPE (intype))
&& TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
{
enum tree_code code = PLUS_EXPR;
tree binfo;
tree intype_class;
tree type_class;
bool same_p;
intype_class = TREE_TYPE (intype);
type_class = TREE_TYPE (type);
same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class),
TYPE_MAIN_VARIANT (type_class));
binfo = NULL_TREE;
/* Try derived to base conversion. */
if (!same_p)
binfo = lookup_base (intype_class, type_class, ba_check, NULL);
if (!same_p && !binfo)
{
/* Try base to derived conversion. */
binfo = lookup_base (type_class, intype_class, ba_check, NULL);
code = MINUS_EXPR;
}
if (binfo == error_mark_node)
return error_mark_node;
if (binfo || same_p)
{
if (binfo)
expr = build_base_path (code, expr, binfo, 0);
/* Add any qualifier conversions. */
return build_nop (type, expr);
}
}
if (TYPE_PTRMEMFUNC_P (type))
{
error ("cannot convert %qE from type %qT to type %qT",
expr, intype, type);
return error_mark_node;
}
return build_nop (type, expr);
}
else if ((TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))
|| (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype)))
return convert_ptrmem (type, expr, /*allow_inverse_p=*/false,
/*c_cast_p=*/false);
else if (TYPE_PTRMEMFUNC_P (intype))
{
if (!warn_pmf2ptr)
{
if (TREE_CODE (expr) == PTRMEM_CST)
return cp_convert_to_pointer (type,
PTRMEM_CST_MEMBER (expr));
else if (TREE_CODE (expr) == OFFSET_REF)
{
tree object = TREE_OPERAND (expr, 0);
return get_member_function_from_ptrfunc (&object,
TREE_OPERAND (expr, 1));
}
}
error ("cannot convert %qE from type %qT to type %qT",
expr, intype, type);
return error_mark_node;
}
if (integer_zerop (expr))
{
if (TYPE_PTRMEMFUNC_P (type))
return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0,
/*c_cast_p=*/false);
if (TYPE_PTRMEM_P (type))
{
/* A NULL pointer-to-member is represented by -1, not by
zero. */
expr = build_int_cst_type (type, -1);
}
else
expr = build_int_cst (type, 0);
return expr;
}
else if (TYPE_PTR_TO_MEMBER_P (type) && INTEGRAL_CODE_P (form))
{
error ("invalid conversion from %qT to %qT", intype, type);
return error_mark_node;
}
if (INTEGRAL_CODE_P (form))
{
if (TYPE_PRECISION (intype) == POINTER_SIZE)
return build1 (CONVERT_EXPR, type, expr);
expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr);
/* Modes may be different but sizes should be the same. There
is supposed to be some integral type that is the same width
as a pointer. */
gcc_assert (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr)))
== GET_MODE_SIZE (TYPE_MODE (type)));
return convert_to_pointer (type, expr);
}
if (type_unknown_p (expr))
return instantiate_type (type, expr, tf_warning_or_error);
error ("cannot convert %qE from type %qT to type %qT",
expr, intype, type);
return error_mark_node;
}
tree
convert_to_void (tree expr, const char *implicit)
{
if (expr == error_mark_node
|| TREE_TYPE (expr) == error_mark_node)
return error_mark_node;
if (!TREE_TYPE (expr))
return expr;
if (invalid_nonstatic_memfn_p (expr))
return error_mark_node;
if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR)
{
error ("pseudo-destructor is not called");
return error_mark_node;
}
if (VOID_TYPE_P (TREE_TYPE (expr)))
return expr;
switch (TREE_CODE (expr))
{
case COND_EXPR:
{
/* The two parts of a cond expr might be separate lvalues. */
tree op1 = TREE_OPERAND (expr,1);
tree op2 = TREE_OPERAND (expr,2);
tree new_op1 = convert_to_void
(op1, (implicit && !TREE_SIDE_EFFECTS (op2)
? "second operand of conditional" : NULL));
tree new_op2 = convert_to_void
(op2, (implicit && !TREE_SIDE_EFFECTS (op1)
? "third operand of conditional" : NULL));
expr = build (COND_EXPR, TREE_TYPE (new_op1),
TREE_OPERAND (expr, 0), new_op1, new_op2);
break;
}
case COMPOUND_EXPR:
{
/* The second part of a compound expr contains the value. */
tree op1 = TREE_OPERAND (expr,1);
tree new_op1 = convert_to_void
(op1, (implicit && !TREE_NO_UNUSED_WARNING (expr)
? "right-hand operand of comma" : NULL));
if (new_op1 != op1)
{
tree t = build (COMPOUND_EXPR, TREE_TYPE (new_op1),
TREE_OPERAND (expr, 0), new_op1);
expr = t;
}
break;
}
case NON_LVALUE_EXPR:
case NOP_EXPR:
/* These have already decayed to rvalue. */
break;
case CALL_EXPR: /* We have a special meaning for volatile void fn(). */
break;
case INDIRECT_REF:
{
tree type = TREE_TYPE (expr);
int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0)))
== REFERENCE_TYPE;
int is_volatile = TYPE_VOLATILE (type);
int is_complete = COMPLETE_TYPE_P (complete_type (type));
if (is_volatile && !is_complete)
warning ("object of incomplete type `%T' will not be accessed in %s",
type, implicit ? implicit : "void context");
else if (is_reference && is_volatile)
warning ("object of type `%T' will not be accessed in %s",
TREE_TYPE (TREE_OPERAND (expr, 0)),
implicit ? implicit : "void context");
if (is_reference || !is_volatile || !is_complete)
expr = TREE_OPERAND (expr, 0);
break;
}
case VAR_DECL:
{
/* External variables might be incomplete. */
tree type = TREE_TYPE (expr);
int is_complete = COMPLETE_TYPE_P (complete_type (type));
if (TYPE_VOLATILE (type) && !is_complete)
warning ("object `%E' of incomplete type `%T' will not be accessed in %s",
expr, type, implicit ? implicit : "void context");
break;
}
default:;
}
{
tree probe = expr;
if (TREE_CODE (probe) == ADDR_EXPR)
probe = TREE_OPERAND (expr, 0);
if (type_unknown_p (probe))
{
/* [over.over] enumerates the places where we can take the address
of an overloaded function, and this is not one of them. */
pedwarn ("%s cannot resolve address of overloaded function",
implicit ? implicit : "void cast");
expr = void_zero_node;
}
else if (implicit && probe == expr && is_overloaded_fn (probe))
/* Only warn when there is no &. */
warning ("%s is a reference, not call, to function `%E'",
implicit, expr);
}
if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr)))
{
if (implicit && !TREE_SIDE_EFFECTS (expr) && warn_unused_value)
warning ("%s has no effect", implicit);
expr = build1 (CONVERT_EXPR, void_type_node, expr);
}
return expr;
}
static tree
cp_convert_to_pointer (tree type, tree expr, bool force)
{
tree intype = TREE_TYPE (expr);
enum tree_code form;
tree rval;
if (intype == error_mark_node)
return error_mark_node;
if (IS_AGGR_TYPE (intype))
{
intype = complete_type (intype);
if (!COMPLETE_TYPE_P (intype))
{
error ("can't convert from incomplete type `%T' to `%T'",
intype, type);
return error_mark_node;
}
rval = build_type_conversion (type, expr);
if (rval)
{
if (rval == error_mark_node)
error ("conversion of `%E' from `%T' to `%T' is ambiguous",
expr, intype, type);
return rval;
}
}
/* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */
if (TREE_CODE (type) == POINTER_TYPE
&& (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
|| VOID_TYPE_P (TREE_TYPE (type))))
{
/* Allow an implicit this pointer for pointer to member
functions. */
if (TYPE_PTRMEMFUNC_P (intype))
{
if (pedantic || warn_pmf2ptr)
pedwarn ("converting from `%T' to `%T'", intype, type);
if (TREE_CODE (expr) == PTRMEM_CST)
expr = build_address (PTRMEM_CST_MEMBER (expr));
else
{
tree decl = maybe_dummy_object (TYPE_PTRMEM_CLASS_TYPE (intype),
0);
decl = build_address (decl);
expr = get_member_function_from_ptrfunc (&decl, expr);
}
}
else if (TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE)
{
if (pedantic || warn_pmf2ptr)
pedwarn ("converting from `%T' to `%T'", intype, type);
expr = build_addr_func (expr);
}
if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE)
return build_nop (type, expr);
intype = TREE_TYPE (expr);
}
if (expr == error_mark_node)
return error_mark_node;
form = TREE_CODE (intype);
if (POINTER_TYPE_P (intype))
{
intype = TYPE_MAIN_VARIANT (intype);
if (TYPE_MAIN_VARIANT (type) != intype
&& TREE_CODE (type) == POINTER_TYPE
&& TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
&& IS_AGGR_TYPE (TREE_TYPE (type))
&& IS_AGGR_TYPE (TREE_TYPE (intype))
&& TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE)
{
enum tree_code code = PLUS_EXPR;
tree binfo;
tree intype_class;
tree type_class;
bool same_p;
intype_class = TREE_TYPE (intype);
type_class = TREE_TYPE (type);
same_p = same_type_p (TYPE_MAIN_VARIANT (intype_class),
TYPE_MAIN_VARIANT (type_class));
binfo = NULL_TREE;
/* Try derived to base conversion. */
if (!same_p)
binfo = lookup_base (intype_class, type_class, ba_check, NULL);
if (!same_p && !binfo)
{
/* Try base to derived conversion. */
binfo = lookup_base (type_class, intype_class, ba_check, NULL);
code = MINUS_EXPR;
}
if (binfo == error_mark_node)
return error_mark_node;
if (binfo || same_p)
{
if (binfo)
expr = build_base_path (code, expr, binfo, 0);
/* Add any qualifier conversions. */
return build_nop (type, expr);
}
}
if (TYPE_PTRMEMFUNC_P (type))
{
error ("cannot convert `%E' from type `%T' to type `%T'",
expr, intype, type);
return error_mark_node;
}
return build_nop (type, expr);
}
else if (TYPE_PTRMEM_P (type) && TYPE_PTRMEM_P (intype))
{
tree b1;
tree b2;
tree binfo;
enum tree_code code = PLUS_EXPR;
base_kind bk;
b1 = TYPE_PTRMEM_CLASS_TYPE (type);
b2 = TYPE_PTRMEM_CLASS_TYPE (intype);
binfo = lookup_base (b1, b2, ba_check, &bk);
if (!binfo)
{
binfo = lookup_base (b2, b1, ba_check, &bk);
code = MINUS_EXPR;
}
if (binfo == error_mark_node)
return error_mark_node;
if (bk == bk_via_virtual)
{
if (force)
warning ("pointer to member cast from `%T' to `%T' is via virtual base",
intype, type);
else
{
error ("pointer to member cast from `%T' to `%T' is via virtual base",
intype, type);
return error_mark_node;
}
/* This is a reinterpret cast, whose result is unspecified.
We choose to do nothing. */
return build1 (NOP_EXPR, type, expr);
}
if (TREE_CODE (expr) == PTRMEM_CST)
expr = cplus_expand_constant (expr);
if (binfo && !integer_zerop (BINFO_OFFSET (binfo)))
expr = size_binop (code,
build_nop (sizetype, expr),
BINFO_OFFSET (binfo));
return build_nop (type, expr);
}
else if (TYPE_PTRMEMFUNC_P (type) && TYPE_PTRMEMFUNC_P (intype))
return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0);
else if (TYPE_PTRMEMFUNC_P (intype))
{
if (!warn_pmf2ptr)
{
if (TREE_CODE (expr) == PTRMEM_CST)
return cp_convert_to_pointer (type,
PTRMEM_CST_MEMBER (expr),
force);
else if (TREE_CODE (expr) == OFFSET_REF)
{
tree object = TREE_OPERAND (expr, 0);
return get_member_function_from_ptrfunc (&object,
TREE_OPERAND (expr, 1));
}
}
error ("cannot convert `%E' from type `%T' to type `%T'",
expr, intype, type);
return error_mark_node;
}
if (integer_zerop (expr))
{
if (TYPE_PTRMEMFUNC_P (type))
return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), expr, 0);
if (TYPE_PTRMEM_P (type))
/* A NULL pointer-to-member is represented by -1, not by
zero. */
expr = build_int_2 (-1, -1);
else
expr = build_int_2 (0, 0);
TREE_TYPE (expr) = type;
/* Fix up the representation of -1 if appropriate. */
force_fit_type (expr, 0);
return expr;
}
else if (TYPE_PTR_TO_MEMBER_P (type) && INTEGRAL_CODE_P (form))
{
error ("invalid conversion from '%T' to '%T'", intype, type);
return error_mark_node;
}
if (INTEGRAL_CODE_P (form))
{
if (TYPE_PRECISION (intype) == POINTER_SIZE)
return build1 (CONVERT_EXPR, type, expr);
expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr);
/* Modes may be different but sizes should be the same. */
if (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr)))
!= GET_MODE_SIZE (TYPE_MODE (type)))
/* There is supposed to be some integral type
that is the same width as a pointer. */
abort ();
return convert_to_pointer (type, expr);
}
if (type_unknown_p (expr))
return instantiate_type (type, expr, tf_error | tf_warning);
error ("cannot convert `%E' from type `%T' to type `%T'",
expr, intype, type);
return error_mark_node;
}
tree
convert_to_void (tree expr, impl_conv_void implicit, tsubst_flags_t complain)
{
if (expr == error_mark_node
|| TREE_TYPE (expr) == error_mark_node)
return error_mark_node;
if (implicit == ICV_CAST)
mark_exp_read (expr);
else
{
tree exprv = expr;
while (TREE_CODE (exprv) == COMPOUND_EXPR)
exprv = TREE_OPERAND (exprv, 1);
if (DECL_P (exprv)
|| handled_component_p (exprv)
|| TREE_CODE (exprv) == INDIRECT_REF)
/* Expr is not being 'used' here, otherwise we whould have
called mark_{rl}value_use use here, which would have in turn
called mark_exp_read. Rather, we call mark_exp_read directly
to avoid some warnings when
-Wunused-but-set-{variable,parameter} is in effect. */
mark_exp_read (exprv);
}
if (!TREE_TYPE (expr))
return expr;
if (invalid_nonstatic_memfn_p (expr, complain))
return error_mark_node;
if (TREE_CODE (expr) == PSEUDO_DTOR_EXPR)
{
if (complain & tf_error)
error ("pseudo-destructor is not called");
return error_mark_node;
}
if (VOID_TYPE_P (TREE_TYPE (expr)))
return expr;
switch (TREE_CODE (expr))
{
case COND_EXPR:
{
/* The two parts of a cond expr might be separate lvalues. */
tree op1 = TREE_OPERAND (expr,1);
tree op2 = TREE_OPERAND (expr,2);
bool side_effects = TREE_SIDE_EFFECTS (op1) || TREE_SIDE_EFFECTS (op2);
tree new_op1, new_op2;
if (implicit != ICV_CAST && !side_effects)
{
new_op1 = convert_to_void (op1, ICV_SECOND_OF_COND, complain);
new_op2 = convert_to_void (op2, ICV_THIRD_OF_COND, complain);
}
else
{
new_op1 = convert_to_void (op1, ICV_CAST, complain);
new_op2 = convert_to_void (op2, ICV_CAST, complain);
}
expr = build3 (COND_EXPR, TREE_TYPE (new_op1),
TREE_OPERAND (expr, 0), new_op1, new_op2);
break;
}
case COMPOUND_EXPR:
{
/* The second part of a compound expr contains the value. */
tree op1 = TREE_OPERAND (expr,1);
tree new_op1;
if (implicit != ICV_CAST && !TREE_NO_WARNING (expr))
new_op1 = convert_to_void (op1, ICV_RIGHT_OF_COMMA, complain);
else
new_op1 = convert_to_void (op1, ICV_CAST, complain);
if (new_op1 != op1)
{
tree t = build2 (COMPOUND_EXPR, TREE_TYPE (new_op1),
TREE_OPERAND (expr, 0), new_op1);
expr = t;
}
break;
}
case NON_LVALUE_EXPR:
case NOP_EXPR:
/* These have already decayed to rvalue. */
break;
case CALL_EXPR: /* We have a special meaning for volatile void fn(). */
break;
case INDIRECT_REF:
{
tree type = TREE_TYPE (expr);
int is_reference = TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0)))
== REFERENCE_TYPE;
int is_volatile = TYPE_VOLATILE (type);
int is_complete = COMPLETE_TYPE_P (complete_type (type));
/* Can't load the value if we don't know the type. */
if (is_volatile && !is_complete)
{
if (complain & tf_warning)
switch (implicit)
{
case ICV_CAST:
warning (0, "conversion to void will not access "
"object of incomplete type %qT", type);
break;
case ICV_SECOND_OF_COND:
warning (0, "indirection will not access object of "
"incomplete type %qT in second operand "
"of conditional expression", type);
break;
case ICV_THIRD_OF_COND:
warning (0, "indirection will not access object of "
"incomplete type %qT in third operand "
"of conditional expression", type);
break;
case ICV_RIGHT_OF_COMMA:
warning (0, "indirection will not access object of "
"incomplete type %qT in right operand of "
"comma operator", type);
break;
case ICV_LEFT_OF_COMMA:
warning (0, "indirection will not access object of "
"incomplete type %qT in left operand of "
"comma operator", type);
break;
case ICV_STATEMENT:
warning (0, "indirection will not access object of "
"incomplete type %qT in statement", type);
break;
case ICV_THIRD_IN_FOR:
warning (0, "indirection will not access object of "
"incomplete type %qT in for increment "
"expression", type);
break;
default:
gcc_unreachable ();
}
}
/* Don't load the value if this is an implicit dereference, or if
the type needs to be handled by ctors/dtors. */
else if (is_volatile && is_reference)
{
if (complain & tf_warning)
switch (implicit)
{
case ICV_CAST:
warning (0, "conversion to void will not access "
"object of type %qT", type);
break;
case ICV_SECOND_OF_COND:
warning (0, "implicit dereference will not access object "
"of type %qT in second operand of "
"conditional expression", type);
break;
case ICV_THIRD_OF_COND:
warning (0, "implicit dereference will not access object "
"of type %qT in third operand of "
"conditional expression", type);
break;
case ICV_RIGHT_OF_COMMA:
warning (0, "implicit dereference will not access object "
"of type %qT in right operand of "
"comma operator", type);
break;
case ICV_LEFT_OF_COMMA:
warning (0, "implicit dereference will not access object "
"of type %qT in left operand of comma operator",
type);
break;
case ICV_STATEMENT:
warning (0, "implicit dereference will not access object "
"of type %qT in statement", type);
break;
case ICV_THIRD_IN_FOR:
warning (0, "implicit dereference will not access object "
"of type %qT in for increment expression",
type);
break;
default:
gcc_unreachable ();
}
}
else if (is_volatile && TREE_ADDRESSABLE (type))
{
if (complain & tf_warning)
switch (implicit)
{
case ICV_CAST:
warning (0, "conversion to void will not access "
"object of non-trivially-copyable type %qT",
type);
break;
case ICV_SECOND_OF_COND:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in second "
"operand of conditional expression", type);
break;
case ICV_THIRD_OF_COND:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in third "
"operand of conditional expression", type);
break;
case ICV_RIGHT_OF_COMMA:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in right "
"operand of comma operator", type);
break;
case ICV_LEFT_OF_COMMA:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in left "
"operand of comma operator", type);
break;
case ICV_STATEMENT:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in statement",
type);
break;
case ICV_THIRD_IN_FOR:
warning (0, "indirection will not access object of "
"non-trivially-copyable type %qT in for "
"increment expression", type);
break;
default:
gcc_unreachable ();
}
}
if (is_reference || !is_volatile || !is_complete || TREE_ADDRESSABLE (type))
{
/* Emit a warning (if enabled) when the "effect-less" INDIRECT_REF
operation is stripped off. Note that we don't warn about
- an expression with TREE_NO_WARNING set. (For an example of
such expressions, see build_over_call in call.c.)
- automatic dereferencing of references, since the user cannot
control it. (See also warn_if_unused_value() in stmt.c.) */
if (warn_unused_value
&& implicit != ICV_CAST
&& (complain & tf_warning)
&& !TREE_NO_WARNING (expr)
&& !is_reference)
warning (OPT_Wunused_value, "value computed is not used");
expr = TREE_OPERAND (expr, 0);
}
break;
}
case VAR_DECL:
{
/* External variables might be incomplete. */
tree type = TREE_TYPE (expr);
int is_complete = COMPLETE_TYPE_P (complete_type (type));
if (TYPE_VOLATILE (type) && !is_complete && (complain & tf_warning))
switch (implicit)
{
case ICV_CAST:
warning (0, "conversion to void will not access "
"object %qE of incomplete type %qT", expr, type);
break;
case ICV_SECOND_OF_COND:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in second operand of "
"conditional expression", expr, type);
break;
case ICV_THIRD_OF_COND:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in third operand of "
"conditional expression", expr, type);
break;
case ICV_RIGHT_OF_COMMA:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in right operand of comma operator",
expr, type);
break;
case ICV_LEFT_OF_COMMA:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in left operand of comma operator",
expr, type);
break;
case ICV_STATEMENT:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in statement", expr, type);
break;
case ICV_THIRD_IN_FOR:
warning (0, "variable %qE of incomplete type %qT will not "
"be accessed in for increment expression",
expr, type);
break;
default:
gcc_unreachable ();
}
break;
}
case TARGET_EXPR:
/* Don't bother with the temporary object returned from a function if
we don't use it and don't need to destroy it. We'll still
allocate space for it in expand_call or declare_return_variable,
but we don't need to track it through all the tree phases. */
if (TARGET_EXPR_IMPLICIT_P (expr)
&& TYPE_HAS_TRIVIAL_DESTRUCTOR (TREE_TYPE (expr)))
{
tree init = TARGET_EXPR_INITIAL (expr);
if (TREE_CODE (init) == AGGR_INIT_EXPR
&& !AGGR_INIT_VIA_CTOR_P (init))
{
tree fn = AGGR_INIT_EXPR_FN (init);
expr = build_call_array_loc (input_location,
TREE_TYPE (TREE_TYPE (TREE_TYPE (fn))),
fn,
aggr_init_expr_nargs (init),
AGGR_INIT_EXPR_ARGP (init));
}
}
break;
default:;
}
expr = resolve_nondeduced_context (expr);
{
tree probe = expr;
if (TREE_CODE (probe) == ADDR_EXPR)
probe = TREE_OPERAND (expr, 0);
if (type_unknown_p (probe))
{
/* [over.over] enumerates the places where we can take the address
of an overloaded function, and this is not one of them. */
if (complain & tf_error)
switch (implicit)
{
case ICV_CAST:
error ("conversion to void "
"cannot resolve address of overloaded function");
break;
case ICV_SECOND_OF_COND:
error ("second operand of conditional expression "
"cannot resolve address of overloaded function");
break;
case ICV_THIRD_OF_COND:
error ("third operand of conditional expression "
"cannot resolve address of overloaded function");
break;
case ICV_RIGHT_OF_COMMA:
error ("right operand of comma operator "
"cannot resolve address of overloaded function");
break;
case ICV_LEFT_OF_COMMA:
error ("left operand of comma operator "
"cannot resolve address of overloaded function");
break;
case ICV_STATEMENT:
error ("statement "
"cannot resolve address of overloaded function");
break;
case ICV_THIRD_IN_FOR:
error ("for increment expression "
"cannot resolve address of overloaded function");
break;
}
else
return error_mark_node;
expr = void_zero_node;
}
else if (implicit != ICV_CAST && probe == expr && is_overloaded_fn (probe))
{
/* Only warn when there is no &. */
if (complain & tf_warning)
switch (implicit)
{
case ICV_SECOND_OF_COND:
warning (OPT_Waddress,
"second operand of conditional expression "
"is a reference, not call, to function %qE", expr);
break;
case ICV_THIRD_OF_COND:
warning (OPT_Waddress,
"third operand of conditional expression "
"is a reference, not call, to function %qE", expr);
break;
case ICV_RIGHT_OF_COMMA:
warning (OPT_Waddress,
"right operand of comma operator "
"is a reference, not call, to function %qE", expr);
break;
case ICV_LEFT_OF_COMMA:
warning (OPT_Waddress,
"left operand of comma operator "
"is a reference, not call, to function %qE", expr);
break;
case ICV_STATEMENT:
warning (OPT_Waddress,
"statement is a reference, not call, to function %qE",
expr);
break;
case ICV_THIRD_IN_FOR:
warning (OPT_Waddress,
"for increment expression "
"is a reference, not call, to function %qE", expr);
break;
default:
gcc_unreachable ();
}
if (TREE_CODE (expr) == COMPONENT_REF)
expr = TREE_OPERAND (expr, 0);
}
}
if (expr != error_mark_node && !VOID_TYPE_P (TREE_TYPE (expr)))
{
if (implicit != ICV_CAST
&& warn_unused_value
&& !TREE_NO_WARNING (expr)
&& !processing_template_decl)
{
/* The middle end does not warn about expressions that have
been explicitly cast to void, so we must do so here. */
if (!TREE_SIDE_EFFECTS (expr)) {
if (complain & tf_warning)
switch (implicit)
{
case ICV_SECOND_OF_COND:
warning (OPT_Wunused_value,
"second operand of conditional expression has no effect");
break;
case ICV_THIRD_OF_COND:
warning (OPT_Wunused_value,
"third operand of conditional expression has no effect");
break;
case ICV_RIGHT_OF_COMMA:
warning (OPT_Wunused_value,
"right operand of comma operator has no effect");
break;
case ICV_LEFT_OF_COMMA:
warning (OPT_Wunused_value,
"left operand of comma operator has no effect");
break;
case ICV_STATEMENT:
warning (OPT_Wunused_value,
"statement has no effect");
break;
case ICV_THIRD_IN_FOR:
warning (OPT_Wunused_value,
"for increment expression has no effect");
break;
default:
gcc_unreachable ();
}
}
else
{
tree e;
enum tree_code code;
enum tree_code_class tclass;
e = expr;
/* We might like to warn about (say) "(int) f()", as the
cast has no effect, but the compiler itself will
generate implicit conversions under some
circumstances. (For example a block copy will be
turned into a call to "__builtin_memcpy", with a
conversion of the return value to an appropriate
type.) So, to avoid false positives, we strip
conversions. Do not use STRIP_NOPs because it will
not strip conversions to "void", as that is not a
mode-preserving conversion. */
while (TREE_CODE (e) == NOP_EXPR)
e = TREE_OPERAND (e, 0);
code = TREE_CODE (e);
tclass = TREE_CODE_CLASS (code);
if ((tclass == tcc_comparison
|| tclass == tcc_unary
|| (tclass == tcc_binary
&& !(code == MODIFY_EXPR
|| code == INIT_EXPR
|| code == PREDECREMENT_EXPR
|| code == PREINCREMENT_EXPR
|| code == POSTDECREMENT_EXPR
|| code == POSTINCREMENT_EXPR)))
&& (complain & tf_warning))
warning (OPT_Wunused_value, "value computed is not used");
}
}
expr = build1 (CONVERT_EXPR, void_type_node, expr);
}
if (! TREE_SIDE_EFFECTS (expr))
expr = void_zero_node;
return expr;
}
