/* Handle exceptional things in C++.
Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- 2000, 2001, 2002, 2003, 2004, 2005, 2007 Free Software Foundation, Inc.
+ 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
+ Free Software Foundation, Inc.
Contributed by Michael Tiemann <tiemann@cygnus.com>
Rewritten by Mike Stump <mrs@cygnus.com>, based upon an
initial re-implementation courtesy Tad Hunt.
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
-#include "rtl.h"
-#include "expr.h"
-#include "libfuncs.h"
#include "cp-tree.h"
#include "flags.h"
#include "output.h"
-#include "except.h"
-#include "toplev.h"
#include "tree-inline.h"
#include "tree-iterator.h"
#include "target.h"
+#include "gimple.h"
static void push_eh_cleanup (tree);
static tree prepare_eh_type (tree);
-static tree build_eh_type_type (tree);
static tree do_begin_catch (void);
static int dtor_nothrow (tree);
static tree do_end_catch (tree);
static int complete_ptr_ref_or_void_ptr_p (tree, tree);
static bool is_admissible_throw_operand (tree);
static int can_convert_eh (tree, tree);
-static tree cp_protect_cleanup_actions (void);
/* Sets up all the global eh stuff that needs to be initialized at the
start of compilation. */
/* void std::terminate (); */
push_namespace (std_identifier);
- tmp = build_function_type (void_type_node, void_list_node);
+ tmp = build_function_type_list (void_type_node, NULL_TREE);
terminate_node = build_cp_library_fn_ptr ("terminate", tmp);
TREE_THIS_VOLATILE (terminate_node) = 1;
TREE_NOTHROW (terminate_node) = 1;
pop_namespace ();
/* void __cxa_call_unexpected(void *); */
- tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
- tmp = build_function_type (void_type_node, tmp);
+ tmp = build_function_type_list (void_type_node, ptr_type_node, NULL_TREE);
call_unexpected_node
= push_throw_library_fn (get_identifier ("__cxa_call_unexpected"), tmp);
-
- eh_personality_libfunc = init_one_libfunc (USING_SJLJ_EXCEPTIONS
- ? "__gxx_personality_sj0"
- : "__gxx_personality_v0");
- if (targetm.arm_eabi_unwinder)
- unwind_resume_libfunc = init_one_libfunc ("__cxa_end_cleanup");
- else
- default_init_unwind_resume_libfunc ();
-
- lang_eh_runtime_type = build_eh_type_type;
- lang_protect_cleanup_actions = &cp_protect_cleanup_actions;
}
/* Returns an expression to be executed if an unhandled exception is
propagated out of a cleanup region. */
-static tree
+tree
cp_protect_cleanup_actions (void)
{
/* [except.terminate]
When the destruction of an object during stack unwinding exits
using an exception ... void terminate(); is called. */
- return build_call_n (terminate_node, 0);
+ return terminate_node;
}
static tree
/* Build the address of a typeinfo decl for use in the runtime
matching field of the exception model. */
-static tree
+tree
build_eh_type_type (tree type)
{
tree exp = eh_type_info (type);
tree
build_exc_ptr (void)
{
- return build0 (EXC_PTR_EXPR, ptr_type_node);
+ return build_call_n (built_in_decls [BUILT_IN_EH_POINTER],
+ 1, integer_zero_node);
+}
+
+/* Declare a function NAME, returning RETURN_TYPE, taking a single
+ parameter PARM_TYPE, with an empty exception specification.
+
+ Note that the C++ ABI document does not have a throw-specifier on
+ the routines declared below via this function. The declarations
+ are consistent with the actual implementations in libsupc++. */
+
+static tree
+declare_nothrow_library_fn (tree name, tree return_type, tree parm_type)
+{
+ return push_library_fn (name, build_function_type_list (return_type,
+ parm_type,
+ NULL_TREE),
+ empty_except_spec);
}
/* Build up a call to __cxa_get_exception_ptr so that we can build a
fn = get_identifier ("__cxa_get_exception_ptr");
if (!get_global_value_if_present (fn, &fn))
{
- /* Declare void* __cxa_get_exception_ptr (void *). */
- tree tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
- fn = push_library_fn (fn, build_function_type (ptr_type_node, tmp));
+ /* Declare void* __cxa_get_exception_ptr (void *) throw(). */
+ fn = declare_nothrow_library_fn (fn, ptr_type_node, ptr_type_node);
}
- return cp_build_function_call (fn, tree_cons (NULL_TREE, build_exc_ptr (),
- NULL_TREE),
- tf_warning_or_error);
+ return cp_build_function_call_nary (fn, tf_warning_or_error,
+ build_exc_ptr (), NULL_TREE);
}
/* Build up a call to __cxa_begin_catch, to tell the runtime that the
fn = get_identifier ("__cxa_begin_catch");
if (!get_global_value_if_present (fn, &fn))
{
- /* Declare void* __cxa_begin_catch (void *). */
- tree tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
- fn = push_library_fn (fn, build_function_type (ptr_type_node, tmp));
+ /* Declare void* __cxa_begin_catch (void *) throw(). */
+ fn = declare_nothrow_library_fn (fn, ptr_type_node, ptr_type_node);
}
- return cp_build_function_call (fn, tree_cons (NULL_TREE, build_exc_ptr (),
- NULL_TREE),
- tf_warning_or_error);
+ return cp_build_function_call_nary (fn, tf_warning_or_error,
+ build_exc_ptr (), NULL_TREE);
}
/* Returns nonzero if cleaning up an exception of type TYPE (which can be
static int
dtor_nothrow (tree type)
{
- if (type == NULL_TREE)
+ if (type == NULL_TREE || type == error_mark_node)
return 0;
- if (!CLASS_TYPE_P (type))
+ if (TYPE_HAS_TRIVIAL_DESTRUCTOR (type))
return 1;
if (CLASSTYPE_LAZY_DESTRUCTOR (type))
TREE_NOTHROW (fn) = 0;
}
- cleanup = cp_build_function_call (fn, NULL_TREE, tf_warning_or_error);
+ cleanup = cp_build_function_call_vec (fn, NULL, tf_warning_or_error);
TREE_NOTHROW (cleanup) = dtor_nothrow (type);
return cleanup;
/* Select the personality routine to be used for exception handling,
or issue an error if we need two different ones in the same
translation unit.
- ??? At present eh_personality_libfunc is set to
- __gxx_personality_(sj|v)0 in init_exception_processing - should it
- be done here instead? */
+ ??? At present DECL_FUNCTION_PERSONALITY is set via
+ LANG_HOOKS_EH_PERSONALITY. Should it be done here instead? */
void
choose_personality_routine (enum languages lang)
{
case lang_java:
state = chose_java;
- eh_personality_libfunc = init_one_libfunc (USING_SJLJ_EXCEPTIONS
- ? "__gcj_personality_sj0"
- : "__gcj_personality_v0");
+ terminate_node = built_in_decls [BUILT_IN_ABORT];
+ pragma_java_exceptions = true;
break;
default:
/* Make sure we mark the catch param as used, otherwise we'll get a
warning about an unused ((anonymous)). */
TREE_USED (decl) = 1;
+ DECL_READ_P (decl) = 1;
/* Figure out the type that the initializer is. Pointers are returned
adjusted by value from __cxa_begin_catch. Others are returned by
pointer catch parm with the address of the temporary. */
if (TREE_CODE (init_type) == REFERENCE_TYPE
&& TYPE_PTR_P (TREE_TYPE (init_type)))
- exp = cp_build_unary_op (ADDR_EXPR, exp, 1, tf_warning_or_error);
+ exp = cp_build_addr_expr (exp, tf_warning_or_error);
exp = ocp_convert (init_type, exp, CONV_IMPLICIT|CONV_FORCE_TEMP, 0);
LOOKUP_ONLYCONVERTING|DIRECT_BIND);
}
+\f
+/* Routine to see if exception handling is turned on.
+ DO_WARN is nonzero if we want to inform the user that exception
+ handling is turned off.
+
+ This is used to ensure that -fexceptions has been specified if the
+ compiler tries to use any exception-specific functions. */
+
+static inline int
+doing_eh (void)
+{
+ if (! flag_exceptions)
+ {
+ static int warned = 0;
+ if (! warned)
+ {
+ error ("exception handling disabled, use -fexceptions to enable");
+ warned = 1;
+ }
+ return 0;
+ }
+ return 1;
+}
+
/* Call this to start a catch block. DECL is the catch parameter. */
tree
expand_start_catch_block (tree decl)
{
tree exp;
- tree type;
+ tree type, init;
- if (! doing_eh (1))
+ if (! doing_eh ())
return NULL_TREE;
/* Make sure this declaration is reasonable. */
exp = build_exc_ptr ();
exp = build1 (NOP_EXPR, build_pointer_type (type), exp);
exp = build2 (POINTER_PLUS_EXPR, TREE_TYPE (exp), exp,
- fold_build1 (NEGATE_EXPR, sizetype,
+ fold_build1_loc (input_location,
+ NEGATE_EXPR, sizetype,
TYPE_SIZE_UNIT (TREE_TYPE (exp))));
- exp = cp_build_indirect_ref (exp, NULL, tf_warning_or_error);
+ exp = cp_build_indirect_ref (exp, RO_NULL, tf_warning_or_error);
initialize_handler_parm (decl, exp);
return type;
}
/* Call __cxa_end_catch at the end of processing the exception. */
push_eh_cleanup (type);
+ init = do_begin_catch ();
+
/* If there's no decl at all, then all we need to do is make sure
to tell the runtime that we've begun handling the exception. */
- if (decl == NULL || decl == error_mark_node)
- finish_expr_stmt (do_begin_catch ());
+ if (decl == NULL || decl == error_mark_node || init == error_mark_node)
+ finish_expr_stmt (init);
/* If the C++ object needs constructing, we need to do that before
calling __cxa_begin_catch, so that std::uncaught_exception gets
{
exp = do_get_exception_ptr ();
initialize_handler_parm (decl, exp);
- finish_expr_stmt (do_begin_catch ());
+ finish_expr_stmt (init);
}
/* Otherwise the type uses a bitwise copy, and we don't have to worry
copy with the return value of __cxa_end_catch instead. */
else
{
- tree init = do_begin_catch ();
tree init_type = type;
/* Pointers are passed by values, everything else by reference. */
void
expand_end_catch_block (void)
{
- if (! doing_eh (1))
+ if (! doing_eh ())
return;
/* The exception being handled is rethrown if control reaches the end of
tree
begin_eh_spec_block (void)
{
- tree r = build_stmt (EH_SPEC_BLOCK, NULL_TREE, NULL_TREE);
+ tree r;
+ /* A noexcept specification (or throw() with -fnothrow-opt) is a
+ MUST_NOT_THROW_EXPR. */
+ if (TYPE_NOEXCEPT_P (TREE_TYPE (current_function_decl)))
+ {
+ r = build_stmt (input_location, MUST_NOT_THROW_EXPR, NULL_TREE);
+ TREE_SIDE_EFFECTS (r) = 1;
+ }
+ else
+ r = build_stmt (input_location, EH_SPEC_BLOCK, NULL_TREE, NULL_TREE);
add_stmt (r);
- EH_SPEC_STMTS (r) = push_stmt_list ();
+ TREE_OPERAND (r, 0) = push_stmt_list ();
return r;
}
{
tree raises;
- EH_SPEC_STMTS (eh_spec_block) = pop_stmt_list (EH_SPEC_STMTS (eh_spec_block));
+ TREE_OPERAND (eh_spec_block, 0)
+ = pop_stmt_list (TREE_OPERAND (eh_spec_block, 0));
+
+ if (TREE_CODE (eh_spec_block) == MUST_NOT_THROW_EXPR)
+ return;
/* Strip cv quals, etc, from the specification types. */
for (raises = NULL_TREE;
fn = get_identifier ("__cxa_allocate_exception");
if (!get_global_value_if_present (fn, &fn))
{
- /* Declare void *__cxa_allocate_exception(size_t). */
- tree tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
- fn = push_library_fn (fn, build_function_type (ptr_type_node, tmp));
+ /* Declare void *__cxa_allocate_exception(size_t) throw(). */
+ fn = declare_nothrow_library_fn (fn, ptr_type_node, size_type_node);
}
- return cp_build_function_call (fn,
- tree_cons (NULL_TREE, size_in_bytes (type),
- NULL_TREE),
- tf_warning_or_error);
+ return cp_build_function_call_nary (fn, tf_warning_or_error,
+ size_in_bytes (type), NULL_TREE);
}
/* Call __cxa_free_exception from a cleanup. This is never invoked
fn = get_identifier ("__cxa_free_exception");
if (!get_global_value_if_present (fn, &fn))
{
- /* Declare void __cxa_free_exception (void *). */
- fn = push_void_library_fn (fn, tree_cons (NULL_TREE, ptr_type_node,
- void_list_node));
+ /* Declare void __cxa_free_exception (void *) throw(). */
+ fn = declare_nothrow_library_fn (fn, void_type_node, ptr_type_node);
}
- return cp_build_function_call (fn, tree_cons (NULL_TREE, ptr, NULL_TREE),
- tf_warning_or_error);
+ return cp_build_function_call_nary (fn, tf_warning_or_error, ptr, NULL_TREE);
}
/* Wrap all cleanups for TARGET_EXPRs in MUST_NOT_THROW_EXPR.
{
if (cfun)
current_function_returns_abnormally = 1;
- return build_min (THROW_EXPR, void_type_node, exp);
+ exp = build_min (THROW_EXPR, void_type_node, exp);
+ SET_EXPR_LOCATION (exp, input_location);
+ return exp;
}
if (exp == null_node)
return error_mark_node;
}
- if (! doing_eh (1))
+ if (! doing_eh ())
return error_mark_node;
if (exp && decl_is_java_type (TREE_TYPE (exp), 1))
if (!get_global_value_if_present (fn, &fn))
{
/* Declare void _Jv_Throw (void *). */
- tree tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
- tmp = build_function_type (ptr_type_node, tmp);
+ tree tmp;
+ tmp = build_function_type_list (ptr_type_node,
+ ptr_type_node, NULL_TREE);
fn = push_throw_library_fn (fn, tmp);
}
else if (really_overloaded_fn (fn))
return error_mark_node;
}
fn = OVL_CURRENT (fn);
- exp = cp_build_function_call (fn, tree_cons (NULL_TREE, exp, NULL_TREE),
- tf_warning_or_error);
+ exp = cp_build_function_call_nary (fn, tf_warning_or_error,
+ exp, NULL_TREE);
}
else if (exp)
{
tree cleanup;
tree object, ptr;
tree tmp;
- tree temp_expr, allocate_expr;
- bool elided;
+ tree allocate_expr;
/* The CLEANUP_TYPE is the internal type of a destructor. */
if (!cleanup_type)
{
- tmp = void_list_node;
- tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
- tmp = build_function_type (void_type_node, tmp);
+ tmp = build_function_type_list (void_type_node,
+ ptr_type_node, NULL_TREE);
cleanup_type = build_pointer_type (tmp);
}
{
/* Declare void __cxa_throw (void*, void*, void (*)(void*)). */
/* ??? Second argument is supposed to be "std::type_info*". */
- tmp = void_list_node;
- tmp = tree_cons (NULL_TREE, cleanup_type, tmp);
- tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
- tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
- tmp = build_function_type (void_type_node, tmp);
+ tmp = build_function_type_list (void_type_node,
+ ptr_type_node, ptr_type_node,
+ cleanup_type, NULL_TREE);
fn = push_throw_library_fn (fn, tmp);
}
allocate_expr = do_allocate_exception (temp_type);
allocate_expr = get_target_expr (allocate_expr);
ptr = TARGET_EXPR_SLOT (allocate_expr);
- object = build_nop (build_pointer_type (temp_type), ptr);
- object = cp_build_indirect_ref (object, NULL, tf_warning_or_error);
+ TARGET_EXPR_CLEANUP (allocate_expr) = do_free_exception (ptr);
+ CLEANUP_EH_ONLY (allocate_expr) = 1;
- elided = (TREE_CODE (exp) == TARGET_EXPR);
+ object = build_nop (build_pointer_type (temp_type), ptr);
+ object = cp_build_indirect_ref (object, RO_NULL, tf_warning_or_error);
/* And initialize the exception object. */
if (CLASS_TYPE_P (temp_type))
{
int flags = LOOKUP_NORMAL | LOOKUP_ONLYCONVERTING;
+ VEC(tree,gc) *exp_vec;
/* Under C++0x [12.8/16 class.copy], a thrown lvalue is sometimes
treated as an rvalue for the purposes of overload resolution
flags = flags | LOOKUP_PREFER_RVALUE;
/* Call the copy constructor. */
+ exp_vec = make_tree_vector_single (exp);
exp = (build_special_member_call
- (object, complete_ctor_identifier,
- build_tree_list (NULL_TREE, exp),
- TREE_TYPE (object),
- flags, tf_warning_or_error));
+ (object, complete_ctor_identifier, &exp_vec,
+ TREE_TYPE (object), flags, tf_warning_or_error));
+ release_tree_vector (exp_vec);
if (exp == error_mark_node)
{
error (" in thrown expression");
}
}
else
- exp = build2 (INIT_EXPR, temp_type, object,
- decay_conversion (exp));
-
- /* Pre-evaluate the thrown expression first, since if we allocated
- the space first we would have to deal with cleaning it up if
- evaluating this expression throws.
-
- The case where EXP the initializer is a cast or a function
- returning a class is a bit of a grey area in the standard; it's
- unclear whether or not it should be allowed to throw. We used to
- say no, as that allowed us to optimize this case without worrying
- about deallocating the exception object if it does. But that
- conflicted with expectations (PR 13944) and the EDG compiler; now
- we wrap the initialization in a TRY_CATCH_EXPR to call
- do_free_exception rather than in a MUST_NOT_THROW_EXPR, for this
- case only.
-
- BUT: Issue 475 may do away with this inconsistency by removing the
- terminate() in this situation.
-
- Note that we don't check the return value from stabilize_init
- because it will only return false in cases where elided is true,
- and therefore we don't need to work around the failure to
- preevaluate. */
- temp_expr = NULL_TREE;
- stabilize_init (exp, &temp_expr);
-
- /* Wrap the initialization in a CLEANUP_POINT_EXPR so that cleanups
- for temporaries within the initialization are run before the one
- for the exception object, preserving LIFO order. */
- exp = build1 (CLEANUP_POINT_EXPR, void_type_node, exp);
+ {
+ tmp = decay_conversion (exp);
+ if (tmp == error_mark_node)
+ return error_mark_node;
+ exp = build2 (INIT_EXPR, temp_type, object, tmp);
+ }
- if (elided)
- exp = build2 (TRY_CATCH_EXPR, void_type_node, exp,
- do_free_exception (ptr));
- else
- exp = build1 (MUST_NOT_THROW_EXPR, void_type_node, exp);
+ /* Mark any cleanups from the initialization as MUST_NOT_THROW, since
+ they are run after the exception object is initialized. */
+ cp_walk_tree_without_duplicates (&exp, wrap_cleanups_r, 0);
/* Prepend the allocation. */
exp = build2 (COMPOUND_EXPR, TREE_TYPE (exp), allocate_expr, exp);
- if (temp_expr)
- {
- /* Prepend the calculation of the throw expression. Also, force
- any cleanups from the expression to be evaluated here so that
- we don't have to do them during unwinding. But first wrap
- them in MUST_NOT_THROW_EXPR, since they are run after the
- exception object is initialized. */
- cp_walk_tree_without_duplicates (&temp_expr, wrap_cleanups_r, 0);
- exp = build2 (COMPOUND_EXPR, TREE_TYPE (exp), temp_expr, exp);
- exp = build1 (CLEANUP_POINT_EXPR, TREE_TYPE (exp), exp);
- }
+
+ /* Force all the cleanups to be evaluated here so that we don't have
+ to do them during unwinding. */
+ exp = build1 (CLEANUP_POINT_EXPR, void_type_node, exp);
throw_type = build_eh_type_type (prepare_eh_type (TREE_TYPE (object)));
else
cleanup = build_int_cst (cleanup_type, 0);
- tmp = tree_cons (NULL_TREE, cleanup, NULL_TREE);
- tmp = tree_cons (NULL_TREE, throw_type, tmp);
- tmp = tree_cons (NULL_TREE, ptr, tmp);
/* ??? Indicate that this function call throws throw_type. */
- tmp = cp_build_function_call (fn, tmp, tf_warning_or_error);
+ tmp = cp_build_function_call_nary (fn, tf_warning_or_error,
+ ptr, throw_type, cleanup, NULL_TREE);
/* Tack on the initialization stuff. */
exp = build2 (COMPOUND_EXPR, TREE_TYPE (tmp), exp, tmp);
{
/* Declare void __cxa_rethrow (void). */
fn = push_throw_library_fn
- (fn, build_function_type (void_type_node, void_list_node));
+ (fn, build_function_type_list (void_type_node, NULL_TREE));
}
/* ??? Indicate that this function call allows exceptions of the type
of the enclosing catch block (if known). */
- exp = cp_build_function_call (fn, NULL_TREE, tf_warning_or_error);
+ exp = cp_build_function_call_vec (fn, NULL, tf_warning_or_error);
}
exp = build1 (THROW_EXPR, void_type_node, exp);
+ SET_EXPR_LOCATION (exp, input_location);
return exp;
}
tree handler = tsi_stmt (i);
if (TREE_TYPE (handler) && can_convert_eh (type, TREE_TYPE (handler)))
{
- warning (0, "%Hexception of type %qT will be caught",
- EXPR_LOCUS (handler), TREE_TYPE (handler));
- warning (0, "%H by earlier handler for %qT",
- EXPR_LOCUS (master), type);
+ warning_at (EXPR_LOCATION (handler), 0,
+ "exception of type %qT will be caught",
+ TREE_TYPE (handler));
+ warning_at (EXPR_LOCATION (master), 0,
+ " by earlier handler for %qT", type);
break;
}
}
if (tsi_end_p (i))
break;
if (TREE_TYPE (handler) == NULL_TREE)
- permerror ("%H%<...%> handler must be the last handler for"
- " its try block", EXPR_LOCUS (handler));
+ permerror (EXPR_LOCATION (handler), "%<...%>"
+ " handler must be the last handler for its try block");
else
check_handlers_1 (handler, i);
}
}
+
+/* walk_tree helper for finish_noexcept_expr. Returns non-null if the
+ expression *TP causes the noexcept operator to evaluate to false.
+
+ 5.3.7 [expr.noexcept]: The result of the noexcept operator is false if
+ in a potentially-evaluated context the expression would contain
+ * a potentially evaluated call to a function, member function,
+ function pointer, or member function pointer that does not have a
+ non-throwing exception-specification (15.4),
+ * a potentially evaluated throw-expression (15.1),
+ * a potentially evaluated dynamic_cast expression dynamic_cast<T>(v),
+ where T is a reference type, that requires a run-time check (5.2.7), or
+ * a potentially evaluated typeid expression (5.2.8) applied to a glvalue
+ expression whose type is a polymorphic class type (10.3). */
+
+static tree
+check_noexcept_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
+ void *data ATTRIBUTE_UNUSED)
+{
+ tree t = *tp;
+ enum tree_code code = TREE_CODE (t);
+ if (code == CALL_EXPR
+ || 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 (TREE_TYPE (fn));
+
+ 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;
+}
+
+/* If a function that causes a noexcept-expression to be false isn't
+ defined yet, remember it and check it for TREE_NOTHROW again at EOF. */
+
+typedef struct GTY(()) pending_noexcept {
+ tree fn;
+ location_t loc;
+} pending_noexcept;
+DEF_VEC_O(pending_noexcept);
+DEF_VEC_ALLOC_O(pending_noexcept,gc);
+static GTY(()) VEC(pending_noexcept,gc) *pending_noexcept_checks;
+
+/* FN is a FUNCTION_DECL that caused a noexcept-expr to be false. Warn if
+ it can't throw. */
+
+static void
+maybe_noexcept_warning (tree fn)
+{
+ if (TREE_NOTHROW (fn))
+ {
+ warning (OPT_Wnoexcept, "noexcept-expression evaluates to %<false%> "
+ "because of a call to %qD", fn);
+ warning (OPT_Wnoexcept, "but %q+D does not throw; perhaps "
+ "it should be declared %<noexcept%>", fn);
+ }
+}
+
+/* Check any functions that weren't defined earlier when they caused a
+ noexcept expression to evaluate to false. */
+
+void
+perform_deferred_noexcept_checks (void)
+{
+ int i;
+ pending_noexcept *p;
+ location_t saved_loc = input_location;
+ FOR_EACH_VEC_ELT (pending_noexcept, pending_noexcept_checks, i, p)
+ {
+ input_location = p->loc;
+ maybe_noexcept_warning (p->fn);
+ }
+ input_location = saved_loc;
+}
+
+/* Evaluate noexcept ( EXPR ). */
+
+tree
+finish_noexcept_expr (tree expr, tsubst_flags_t complain)
+{
+ tree fn;
+
+ if (expr == error_mark_node)
+ return error_mark_node;
+
+ if (processing_template_decl)
+ return build_min (NOEXCEPT_EXPR, boolean_type_node, expr);
+
+ fn = cp_walk_tree_without_duplicates (&expr, check_noexcept_r, 0);
+ if (fn)
+ {
+ if ((complain & tf_warning) && warn_noexcept
+ && TREE_CODE (fn) == FUNCTION_DECL)
+ {
+ if (!DECL_INITIAL (fn))
+ {
+ /* Not defined yet; check again at EOF. */
+ pending_noexcept *p
+ = VEC_safe_push (pending_noexcept, gc,
+ pending_noexcept_checks, NULL);
+ p->fn = fn;
+ p->loc = input_location;
+ }
+ else
+ maybe_noexcept_warning (fn);
+ }
+ return boolean_false_node;
+ }
+ else
+ return boolean_true_node;
+}
+
+/* Return true iff SPEC is throw() or noexcept(true). */
+
+bool
+nothrow_spec_p (const_tree spec)
+{
+ if (spec == NULL_TREE
+ || TREE_VALUE (spec) != NULL_TREE
+ || spec == noexcept_false_spec)
+ return false;
+ if (TREE_PURPOSE (spec) == NULL_TREE
+ || spec == noexcept_true_spec)
+ return true;
+ gcc_assert (processing_template_decl
+ || TREE_PURPOSE (spec) == error_mark_node);
+ return false;
+}
+
+/* For FUNCTION_TYPE or METHOD_TYPE, true if NODE is noexcept. This is the
+ case for things declared noexcept(true) and, with -fnothrow-opt, for
+ throw() functions. */
+
+bool
+type_noexcept_p (const_tree type)
+{
+ tree spec = TYPE_RAISES_EXCEPTIONS (type);
+ if (flag_nothrow_opt)
+ return nothrow_spec_p (spec);
+ else
+ return spec == noexcept_true_spec;
+}
+
+/* For FUNCTION_TYPE or METHOD_TYPE, true if NODE can throw any type,
+ i.e. no exception-specification or noexcept(false). */
+
+bool
+type_throw_all_p (const_tree type)
+{
+ tree spec = TYPE_RAISES_EXCEPTIONS (type);
+ return spec == NULL_TREE || spec == noexcept_false_spec;
+}
+
+/* Create a representation of the noexcept-specification with
+ constant-expression of EXPR. COMPLAIN is as for tsubst. */
+
+tree
+build_noexcept_spec (tree expr, int complain)
+{
+ /* This isn't part of the signature, so don't bother trying to evaluate
+ it until instantiation. */
+ if (!processing_template_decl)
+ {
+ expr = perform_implicit_conversion_flags (boolean_type_node, expr,
+ complain,
+ LOOKUP_NORMAL);
+ expr = cxx_constant_value (expr);
+ }
+ if (expr == boolean_true_node)
+ return noexcept_true_spec;
+ else if (expr == boolean_false_node)
+ return noexcept_false_spec;
+ else if (expr == error_mark_node)
+ return error_mark_node;
+ else
+ {
+ gcc_assert (processing_template_decl || expr == error_mark_node);
+ return build_tree_list (expr, NULL_TREE);
+ }
+}
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