static tree
check_noexcept_r (tree *tp, int * /*walk_subtrees*/, void * /*data*/)
{
tree t = *tp;
enum tree_code code = TREE_CODE (t);
if ((code == CALL_EXPR && CALL_EXPR_FN (t))
|| code == AGGR_INIT_EXPR)
{
/* We can only use the exception specification of the called function
for determining the value of a noexcept expression; we can't use
TREE_NOTHROW, as it might have a different value in another
translation unit, creating ODR problems.
We could use TREE_NOTHROW (t) for !TREE_PUBLIC fns, though... */
tree fn = (code == AGGR_INIT_EXPR
? AGGR_INIT_EXPR_FN (t) : CALL_EXPR_FN (t));
tree type = TREE_TYPE (fn);
gcc_assert (POINTER_TYPE_P (type));
type = TREE_TYPE (type);
STRIP_NOPS (fn);
if (TREE_CODE (fn) == ADDR_EXPR)
fn = TREE_OPERAND (fn, 0);
if (TREE_CODE (fn) == FUNCTION_DECL)
{
/* We do use TREE_NOTHROW for ABI internals like __dynamic_cast,
and for C library functions known not to throw. */
if (DECL_EXTERN_C_P (fn)
&& (DECL_ARTIFICIAL (fn)
|| nothrow_libfn_p (fn)))
return TREE_NOTHROW (fn) ? NULL_TREE : fn;
/* A call to a constexpr function is noexcept if the call
is a constant expression. */
if (DECL_DECLARED_CONSTEXPR_P (fn)
&& is_sub_constant_expr (t))
return NULL_TREE;
}
if (!TYPE_NOTHROW_P (type))
return fn;
}
return NULL_TREE;
}
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;
}
bool
cp_dump_tree (void* dump_info, tree t)
{
enum tree_code code;
dump_info_p di = (dump_info_p) dump_info;
/* Figure out what kind of node this is. */
code = TREE_CODE (t);
if (DECL_P (t))
{
if (DECL_LANG_SPECIFIC (t) && DECL_LANGUAGE (t) != lang_cplusplus)
dump_string_field (di, "lang", language_to_string (DECL_LANGUAGE (t)));
}
switch (code)
{
case IDENTIFIER_NODE:
if (IDENTIFIER_OPNAME_P (t))
{
dump_string_field (di, "note", "operator");
return true;
}
else if (IDENTIFIER_TYPENAME_P (t))
{
dump_child ("tynm", TREE_TYPE (t));
return true;
}
break;
case OFFSET_TYPE:
dump_string_field (di, "note", "ptrmem");
dump_child ("ptd", TYPE_PTRMEM_POINTED_TO_TYPE (t));
dump_child ("cls", TYPE_PTRMEM_CLASS_TYPE (t));
return true;
case RECORD_TYPE:
if (TYPE_PTRMEMFUNC_P (t))
{
dump_string_field (di, "note", "ptrmem");
dump_child ("ptd", TYPE_PTRMEM_POINTED_TO_TYPE (t));
dump_child ("cls", TYPE_PTRMEM_CLASS_TYPE (t));
return true;
}
/* Fall through. */
case UNION_TYPE:
/* Is it a type used as a base? */
if (TYPE_CONTEXT (t) && TREE_CODE (TYPE_CONTEXT (t)) == TREE_CODE (t)
&& CLASSTYPE_AS_BASE (TYPE_CONTEXT (t)) == t)
{
dump_child ("bfld", TYPE_CONTEXT (t));
return true;
}
if (! MAYBE_CLASS_TYPE_P (t))
break;
dump_child ("vfld", TYPE_VFIELD (t));
if (CLASSTYPE_TEMPLATE_SPECIALIZATION(t))
dump_string(di, "spec");
if (!dump_flag (di, TDF_SLIM, t) && TYPE_BINFO (t))
{
int i;
tree binfo;
tree base_binfo;
for (binfo = TYPE_BINFO (t), i = 0;
BINFO_BASE_ITERATE (binfo, i, base_binfo); ++i)
{
dump_child ("base", BINFO_TYPE (base_binfo));
if (BINFO_VIRTUAL_P (base_binfo))
dump_string_field (di, "spec", "virt");
dump_access (di, base_binfo);
}
}
break;
case FIELD_DECL:
dump_access (di, t);
if (DECL_MUTABLE_P (t))
dump_string_field (di, "spec", "mutable");
break;
case VAR_DECL:
if (TREE_CODE (CP_DECL_CONTEXT (t)) == RECORD_TYPE)
dump_access (di, t);
if (TREE_STATIC (t) && !TREE_PUBLIC (t))
dump_string_field (di, "link", "static");
break;
case FUNCTION_DECL:
if (!DECL_THUNK_P (t))
{
if (DECL_OVERLOADED_OPERATOR_P (t)) {
dump_string_field (di, "note", "operator");
dump_op (di, t);
}
if (DECL_FUNCTION_MEMBER_P (t))
{
dump_string_field (di, "note", "member");
dump_access (di, t);
}
if (DECL_PURE_VIRTUAL_P (t))
dump_string_field (di, "spec", "pure");
if (DECL_VIRTUAL_P (t))
dump_string_field (di, "spec", "virt");
if (DECL_CONSTRUCTOR_P (t))
dump_string_field (di, "note", "constructor");
if (DECL_DESTRUCTOR_P (t))
dump_string_field (di, "note", "destructor");
if (DECL_CONV_FN_P (t))
dump_string_field (di, "note", "conversion");
if (DECL_GLOBAL_CTOR_P (t))
dump_string_field (di, "note", "global init");
if (DECL_GLOBAL_DTOR_P (t))
dump_string_field (di, "note", "global fini");
if (DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION (t))
dump_string_field (di, "note", "pseudo tmpl");
}
else
{
tree virt = THUNK_VIRTUAL_OFFSET (t);
dump_string_field (di, "note", "thunk");
if (DECL_THIS_THUNK_P (t))
dump_string_field (di, "note", "this adjusting");
else
{
dump_string_field (di, "note", "result adjusting");
if (virt)
virt = BINFO_VPTR_FIELD (virt);
}
dump_int (di, "fixd", THUNK_FIXED_OFFSET (t));
if (virt)
dump_int (di, "virt", tree_to_shwi (virt));
dump_child ("fn", DECL_INITIAL (t));
}
break;
case NAMESPACE_DECL:
if (DECL_NAMESPACE_ALIAS (t))
dump_child ("alis", DECL_NAMESPACE_ALIAS (t));
else if (!dump_flag (di, TDF_SLIM, t))
dump_child ("dcls", cp_namespace_decls (t));
break;
case TEMPLATE_DECL:
dump_child ("rslt", DECL_TEMPLATE_RESULT (t));
dump_child ("inst", DECL_TEMPLATE_INSTANTIATIONS (t));
dump_child ("spcs", DECL_TEMPLATE_SPECIALIZATIONS (t));
dump_child ("prms", DECL_TEMPLATE_PARMS (t));
break;
case OVERLOAD:
dump_child ("crnt", OVL_CURRENT (t));
dump_child ("chan", OVL_CHAIN (t));
break;
case TRY_BLOCK:
dump_stmt (di, t);
if (CLEANUP_P (t))
dump_string_field (di, "note", "cleanup");
dump_child ("body", TRY_STMTS (t));
dump_child ("hdlr", TRY_HANDLERS (t));
break;
case EH_SPEC_BLOCK:
dump_stmt (di, t);
dump_child ("body", EH_SPEC_STMTS (t));
dump_child ("raises", EH_SPEC_RAISES (t));
break;
case PTRMEM_CST:
dump_child ("clas", PTRMEM_CST_CLASS (t));
dump_child ("mbr", PTRMEM_CST_MEMBER (t));
break;
case THROW_EXPR:
/* These nodes are unary, but do not have code class `1'. */
dump_child ("op 0", TREE_OPERAND (t, 0));
break;
case AGGR_INIT_EXPR:
{
int i = 0;
tree arg;
aggr_init_expr_arg_iterator iter;
dump_int (di, "ctor", AGGR_INIT_VIA_CTOR_P (t));
dump_child ("fn", AGGR_INIT_EXPR_FN (t));
FOR_EACH_AGGR_INIT_EXPR_ARG (arg, iter, t)
{
char buffer[32];
sprintf (buffer, "%u", i);
dump_child (buffer, arg);
i++;
}
dump_child ("decl", AGGR_INIT_EXPR_SLOT (t));
}
break;
case HANDLER:
dump_stmt (di, t);
dump_child ("parm", HANDLER_PARMS (t));
dump_child ("body", HANDLER_BODY (t));
break;
case MUST_NOT_THROW_EXPR:
dump_stmt (di, t);
dump_child ("body", TREE_OPERAND (t, 0));
dump_child ("cond", MUST_NOT_THROW_COND (t));
break;
case USING_STMT:
dump_stmt (di, t);
dump_child ("nmsp", USING_STMT_NAMESPACE (t));
break;
case CLEANUP_STMT:
dump_stmt (di, t);
dump_child ("decl", CLEANUP_DECL (t));
dump_child ("expr", CLEANUP_EXPR (t));
dump_child ("body", CLEANUP_BODY (t));
break;
case IF_STMT:
dump_stmt (di, t);
dump_child ("cond", IF_COND (t));
dump_child ("then", THEN_CLAUSE (t));
dump_child ("else", ELSE_CLAUSE (t));
break;
case BREAK_STMT:
case CONTINUE_STMT:
dump_stmt (di, t);
break;
case DO_STMT:
dump_stmt (di, t);
dump_child ("body", DO_BODY (t));
dump_child ("cond", DO_COND (t));
break;
case FOR_STMT:
dump_stmt (di, t);
dump_child ("init", FOR_INIT_STMT (t));
dump_child ("cond", FOR_COND (t));
dump_child ("expr", FOR_EXPR (t));
dump_child ("body", FOR_BODY (t));
break;
case RANGE_FOR_STMT:
dump_stmt (di, t);
dump_child ("decl", RANGE_FOR_DECL (t));
dump_child ("expr", RANGE_FOR_EXPR (t));
dump_child ("body", RANGE_FOR_BODY (t));
break;
case SWITCH_STMT:
dump_stmt (di, t);
dump_child ("cond", SWITCH_STMT_COND (t));
dump_child ("body", SWITCH_STMT_BODY (t));
break;
case WHILE_STMT:
dump_stmt (di, t);
dump_child ("cond", WHILE_COND (t));
dump_child ("body", WHILE_BODY (t));
break;
case STMT_EXPR:
dump_child ("stmt", STMT_EXPR_STMT (t));
break;
case EXPR_STMT:
dump_stmt (di, t);
dump_child ("expr", EXPR_STMT_EXPR (t));
break;
default:
break;
}
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;
}