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except.c
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except.c
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/* Handle exceptional things in C++.
Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2012
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.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "cp-tree.h"
#include "flags.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 do_begin_catch (void);
static int dtor_nothrow (tree);
static tree do_end_catch (tree);
static bool decl_is_java_type (tree decl, int err);
static void initialize_handler_parm (tree, tree);
static tree do_allocate_exception (tree);
static tree wrap_cleanups_r (tree *, int *, void *);
static int complete_ptr_ref_or_void_ptr_p (tree, tree);
static bool is_admissible_throw_operand_or_catch_parameter (tree, bool);
static int can_convert_eh (tree, tree);
/* Sets up all the global eh stuff that needs to be initialized at the
start of compilation. */
void
init_exception_processing (void)
{
tree tmp;
/* void std::terminate (); */
push_namespace (std_identifier);
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 = 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);
}
/* Returns an expression to be executed if an unhandled exception is
propagated out of a cleanup region. */
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 terminate_node;
}
static tree
prepare_eh_type (tree type)
{
if (type == NULL_TREE)
return type;
if (type == error_mark_node)
return error_mark_node;
/* peel back references, so they match. */
type = non_reference (type);
/* Peel off cv qualifiers. */
type = TYPE_MAIN_VARIANT (type);
/* Functions and arrays decay to pointers. */
type = type_decays_to (type);
return type;
}
/* Return the type info for TYPE as used by EH machinery. */
tree
eh_type_info (tree type)
{
tree exp;
if (type == NULL_TREE || type == error_mark_node)
return type;
if (decl_is_java_type (type, 0))
exp = build_java_class_ref (TREE_TYPE (type));
else
exp = get_tinfo_decl (type);
return exp;
}
/* Build the address of a typeinfo decl for use in the runtime
matching field of the exception model. */
tree
build_eh_type_type (tree type)
{
tree exp = eh_type_info (type);
if (!exp)
return NULL;
mark_used (exp);
return convert (ptr_type_node, build_address (exp));
}
tree
build_exc_ptr (void)
{
return build_call_n (builtin_decl_explicit (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
copy constructor for the thrown object. */
static tree
do_get_exception_ptr (void)
{
tree fn;
fn = get_identifier ("__cxa_get_exception_ptr");
if (!get_global_value_if_present (fn, &fn))
{
/* Declare void* __cxa_get_exception_ptr (void *) throw(). */
fn = declare_nothrow_library_fn (fn, ptr_type_node, ptr_type_node);
if (flag_tm)
apply_tm_attr (fn, get_identifier ("transaction_pure"));
}
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
exception has been handled. */
static tree
do_begin_catch (void)
{
tree fn;
fn = get_identifier ("__cxa_begin_catch");
if (!get_global_value_if_present (fn, &fn))
{
/* Declare void* __cxa_begin_catch (void *) throw(). */
fn = declare_nothrow_library_fn (fn, ptr_type_node, ptr_type_node);
/* Create its transactional-memory equivalent. */
if (flag_tm)
{
tree fn2 = get_identifier ("_ITM_cxa_begin_catch");
if (!get_global_value_if_present (fn2, &fn2))
fn2 = declare_nothrow_library_fn (fn2, ptr_type_node,
ptr_type_node);
apply_tm_attr (fn2, get_identifier ("transaction_pure"));
record_tm_replacement (fn, fn2);
}
}
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
NULL_TREE for a ... handler) will not throw an exception. */
static int
dtor_nothrow (tree type)
{
if (type == NULL_TREE || type == error_mark_node)
return 0;
if (TYPE_HAS_TRIVIAL_DESTRUCTOR (type))
return 1;
if (CLASSTYPE_LAZY_DESTRUCTOR (type))
lazily_declare_fn (sfk_destructor, type);
return TREE_NOTHROW (CLASSTYPE_DESTRUCTORS (type));
}
/* Build up a call to __cxa_end_catch, to destroy the exception object
for the current catch block if no others are currently using it. */
static tree
do_end_catch (tree type)
{
tree fn, cleanup;
fn = get_identifier ("__cxa_end_catch");
if (!get_global_value_if_present (fn, &fn))
{
/* Declare void __cxa_end_catch (). */
fn = push_void_library_fn (fn, void_list_node);
/* This can throw if the destructor for the exception throws. */
TREE_NOTHROW (fn) = 0;
/* Create its transactional-memory equivalent. */
if (flag_tm)
{
tree fn2 = get_identifier ("_ITM_cxa_end_catch");
if (!get_global_value_if_present (fn2, &fn2))
{
fn2 = push_void_library_fn (fn2, void_list_node);
TREE_NOTHROW (fn2) = 0;
}
apply_tm_attr (fn2, get_identifier ("transaction_pure"));
record_tm_replacement (fn, fn2);
}
}
cleanup = cp_build_function_call_vec (fn, NULL, tf_warning_or_error);
TREE_NOTHROW (cleanup) = dtor_nothrow (type);
return cleanup;
}
/* This routine creates the cleanup for the current exception. */
static void
push_eh_cleanup (tree type)
{
finish_decl_cleanup (NULL_TREE, do_end_catch (type));
}
/* Return nonzero value if DECL is a Java type suitable for catch or
throw. */
static bool
decl_is_java_type (tree decl, int err)
{
bool r = (TREE_CODE (decl) == POINTER_TYPE
&& TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
&& TYPE_FOR_JAVA (TREE_TYPE (decl)));
if (err)
{
if (TREE_CODE (decl) == REFERENCE_TYPE
&& TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
&& TYPE_FOR_JAVA (TREE_TYPE (decl)))
{
/* Can't throw a reference. */
error ("type %qT is disallowed in Java %<throw%> or %<catch%>",
decl);
}
if (r)
{
tree jthrow_node
= IDENTIFIER_GLOBAL_VALUE (get_identifier ("jthrowable"));
if (jthrow_node == NULL_TREE)
fatal_error
("call to Java %<catch%> or %<throw%> with %<jthrowable%> undefined");
jthrow_node = TREE_TYPE (TREE_TYPE (jthrow_node));
if (! DERIVED_FROM_P (jthrow_node, TREE_TYPE (decl)))
{
/* Thrown object must be a Throwable. */
error ("type %qT is not derived from %<java::lang::Throwable%>",
TREE_TYPE (decl));
}
}
}
return r;
}
/* 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 DECL_FUNCTION_PERSONALITY is set via
LANG_HOOKS_EH_PERSONALITY. Should it be done here instead? */
void
choose_personality_routine (enum languages lang)
{
static enum {
chose_none,
chose_cpp,
chose_java,
gave_error
} state;
switch (state)
{
case gave_error:
return;
case chose_cpp:
if (lang != lang_cplusplus)
goto give_error;
return;
case chose_java:
if (lang != lang_java)
goto give_error;
return;
case chose_none:
; /* Proceed to language selection. */
}
switch (lang)
{
case lang_cplusplus:
state = chose_cpp;
break;
case lang_java:
state = chose_java;
terminate_node = builtin_decl_explicit (BUILT_IN_ABORT);
pragma_java_exceptions = true;
break;
default:
gcc_unreachable ();
}
return;
give_error:
error ("mixing C++ and Java catches in a single translation unit");
state = gave_error;
}
/* Wrap EXPR in a MUST_NOT_THROW_EXPR expressing that EXPR must
not throw any exceptions if COND is true. A condition of
NULL_TREE is treated as 'true'. */
tree
build_must_not_throw_expr (tree body, tree cond)
{
tree type = body ? TREE_TYPE (body) : void_type_node;
if (cond && !value_dependent_expression_p (cond))
{
cond = cxx_constant_value (cond);
if (integer_zerop (cond))
return body;
else if (integer_onep (cond))
cond = NULL_TREE;
}
return build2 (MUST_NOT_THROW_EXPR, type, body, cond);
}
/* Initialize the catch parameter DECL. */
static void
initialize_handler_parm (tree decl, tree exp)
{
tree init;
tree init_type;
/* 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
reference. */
init_type = TREE_TYPE (decl);
if (!POINTER_TYPE_P (init_type))
init_type = build_reference_type (init_type);
choose_personality_routine (decl_is_java_type (init_type, 0)
? lang_java : lang_cplusplus);
/* Since pointers are passed by value, initialize a reference to
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_addr_expr (exp, tf_warning_or_error);
exp = ocp_convert (init_type, exp, CONV_IMPLICIT|CONV_FORCE_TEMP, 0,
tf_warning_or_error);
init = convert_from_reference (exp);
/* If the constructor for the catch parm exits via an exception, we
must call terminate. See eh23.C. */
if (TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl)))
{
/* Generate the copy constructor call directly so we can wrap it.
See also expand_default_init. */
init = ocp_convert (TREE_TYPE (decl), init,
CONV_IMPLICIT|CONV_FORCE_TEMP, 0,
tf_warning_or_error);
/* Force cleanups now to avoid nesting problems with the
MUST_NOT_THROW_EXPR. */
init = fold_build_cleanup_point_expr (TREE_TYPE (init), init);
init = build_must_not_throw_expr (init, NULL_TREE);
}
decl = pushdecl (decl);
start_decl_1 (decl, true);
cp_finish_decl (decl, init, /*init_const_expr_p=*/false, NULL_TREE,
LOOKUP_ONLYCONVERTING|DIRECT_BIND);
}
/* 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, init;
if (! doing_eh ())
return NULL_TREE;
if (decl)
{
if (!is_admissible_throw_operand_or_catch_parameter (decl, false))
decl = error_mark_node;
type = prepare_eh_type (TREE_TYPE (decl));
}
else
type = NULL_TREE;
if (decl && decl_is_java_type (type, 1))
{
/* Java only passes object via pointer and doesn't require
adjusting. The java object is immediately before the
generic exception header. */
exp = build_exc_ptr ();
exp = build1 (NOP_EXPR, build_pointer_type (type), exp);
exp = fold_build_pointer_plus (exp,
fold_build1_loc (input_location,
NEGATE_EXPR, sizetype,
TYPE_SIZE_UNIT (TREE_TYPE (exp))));
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 || 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
the right value during the copy constructor. */
else if (flag_use_cxa_get_exception_ptr
&& TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl)))
{
exp = do_get_exception_ptr ();
initialize_handler_parm (decl, exp);
finish_expr_stmt (init);
}
/* Otherwise the type uses a bitwise copy, and we don't have to worry
about the value of std::uncaught_exception and therefore can do the
copy with the return value of __cxa_end_catch instead. */
else
{
tree init_type = type;
/* Pointers are passed by values, everything else by reference. */
if (!TYPE_PTR_P (type))
init_type = build_pointer_type (type);
if (init_type != TREE_TYPE (init))
init = build1 (NOP_EXPR, init_type, init);
exp = create_temporary_var (init_type);
DECL_REGISTER (exp) = 1;
cp_finish_decl (exp, init, /*init_const_expr=*/false,
NULL_TREE, LOOKUP_ONLYCONVERTING);
initialize_handler_parm (decl, exp);
}
return type;
}
/* Call this to end a catch block. Its responsible for emitting the
code to handle jumping back to the correct place, and for emitting
the label to jump to if this catch block didn't match. */
void
expand_end_catch_block (void)
{
if (! doing_eh ())
return;
/* The exception being handled is rethrown if control reaches the end of
a handler of the function-try-block of a constructor or destructor. */
if (in_function_try_handler
&& (DECL_CONSTRUCTOR_P (current_function_decl)
|| DECL_DESTRUCTOR_P (current_function_decl)))
finish_expr_stmt (build_throw (NULL_TREE));
}
tree
begin_eh_spec_block (void)
{
tree r;
location_t spec_location = DECL_SOURCE_LOCATION (current_function_decl);
/* 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 (spec_location, MUST_NOT_THROW_EXPR,
NULL_TREE, NULL_TREE);
TREE_SIDE_EFFECTS (r) = 1;
}
else
r = build_stmt (spec_location, EH_SPEC_BLOCK, NULL_TREE, NULL_TREE);
add_stmt (r);
TREE_OPERAND (r, 0) = push_stmt_list ();
return r;
}
void
finish_eh_spec_block (tree raw_raises, tree eh_spec_block)
{
tree raises;
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;
raw_raises && TREE_VALUE (raw_raises);
raw_raises = TREE_CHAIN (raw_raises))
{
tree type = prepare_eh_type (TREE_VALUE (raw_raises));
tree tinfo = eh_type_info (type);
mark_used (tinfo);
raises = tree_cons (NULL_TREE, type, raises);
}
EH_SPEC_RAISES (eh_spec_block) = raises;
}
/* Return a pointer to a buffer for an exception object of type TYPE. */
static tree
do_allocate_exception (tree type)
{
tree fn;
fn = get_identifier ("__cxa_allocate_exception");
if (!get_global_value_if_present (fn, &fn))
{
/* Declare void *__cxa_allocate_exception(size_t) throw(). */
fn = declare_nothrow_library_fn (fn, ptr_type_node, size_type_node);
if (flag_tm)
{
tree fn2 = get_identifier ("_ITM_cxa_allocate_exception");
if (!get_global_value_if_present (fn2, &fn2))
fn2 = declare_nothrow_library_fn (fn2, ptr_type_node,
size_type_node);
apply_tm_attr (fn2, get_identifier ("transaction_pure"));
record_tm_replacement (fn, fn2);
}
}
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
directly, but see the comment for stabilize_throw_expr. */
static tree
do_free_exception (tree ptr)
{
tree fn;
fn = get_identifier ("__cxa_free_exception");
if (!get_global_value_if_present (fn, &fn))
{
/* Declare void __cxa_free_exception (void *) throw(). */
fn = declare_nothrow_library_fn (fn, void_type_node, ptr_type_node);
}
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.
Called from build_throw via walk_tree_without_duplicates. */
static tree
wrap_cleanups_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
void *data ATTRIBUTE_UNUSED)
{
tree exp = *tp;
tree cleanup;
/* Don't walk into types. */
if (TYPE_P (exp))
{
*walk_subtrees = 0;
return NULL_TREE;
}
if (TREE_CODE (exp) != TARGET_EXPR)
return NULL_TREE;
cleanup = TARGET_EXPR_CLEANUP (exp);
if (cleanup)
{
cleanup = build2 (MUST_NOT_THROW_EXPR, void_type_node, cleanup,
NULL_TREE);
TARGET_EXPR_CLEANUP (exp) = cleanup;
}
/* Keep iterating. */
return NULL_TREE;
}
/* Build a throw expression. */
tree
build_throw (tree exp)
{
tree fn;
if (exp == error_mark_node)
return exp;
if (processing_template_decl)
{
if (cfun)
current_function_returns_abnormally = 1;
exp = build_min (THROW_EXPR, void_type_node, exp);
SET_EXPR_LOCATION (exp, input_location);
return exp;
}
if (exp == null_node)
warning (0, "throwing NULL, which has integral, not pointer type");
if (exp != NULL_TREE)
{
if (!is_admissible_throw_operand_or_catch_parameter (exp, true))
return error_mark_node;
}
if (! doing_eh ())
return error_mark_node;
if (exp && decl_is_java_type (TREE_TYPE (exp), 1))
{
tree fn = get_identifier ("_Jv_Throw");
if (!get_global_value_if_present (fn, &fn))
{
/* Declare void _Jv_Throw (void *). */
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))
{
error ("%qD should never be overloaded", fn);
return error_mark_node;
}
fn = OVL_CURRENT (fn);
exp = cp_build_function_call_nary (fn, tf_warning_or_error,
exp, NULL_TREE);
}
else if (exp)
{
tree throw_type;
tree temp_type;
tree cleanup;
tree object, ptr;
tree tmp;
tree allocate_expr;
/* The CLEANUP_TYPE is the internal type of a destructor. */
if (!cleanup_type)
{
tmp = build_function_type_list (void_type_node,
ptr_type_node, NULL_TREE);
cleanup_type = build_pointer_type (tmp);
}
fn = get_identifier ("__cxa_throw");
if (!get_global_value_if_present (fn, &fn))
{
/* Declare void __cxa_throw (void*, void*, void (*)(void*)). */
/* ??? Second argument is supposed to be "std::type_info*". */
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);
if (flag_tm)
{
tree fn2 = get_identifier ("_ITM_cxa_throw");
if (!get_global_value_if_present (fn2, &fn2))
fn2 = push_throw_library_fn (fn2, tmp);
apply_tm_attr (fn2, get_identifier ("transaction_pure"));
record_tm_replacement (fn, fn2);
}
}
/* [except.throw]
A throw-expression initializes a temporary object, the type
of which is determined by removing any top-level
cv-qualifiers from the static type of the operand of throw
and adjusting the type from "array of T" or "function return
T" to "pointer to T" or "pointer to function returning T"
respectively. */
temp_type = is_bitfield_expr_with_lowered_type (exp);
if (!temp_type)
temp_type = cv_unqualified (type_decays_to (TREE_TYPE (exp)));
/* OK, this is kind of wacky. The standard says that we call
terminate when the exception handling mechanism, after
completing evaluation of the expression to be thrown but
before the exception is caught (_except.throw_), calls a
user function that exits via an uncaught exception.
So we have to protect the actual initialization of the
exception object with terminate(), but evaluate the
expression first. Since there could be temps in the
expression, we need to handle that, too. We also expand
the call to __cxa_allocate_exception first (which doesn't
matter, since it can't throw). */
/* Allocate the space for the exception. */
allocate_expr = do_allocate_exception (temp_type);
allocate_expr = get_target_expr (allocate_expr);
ptr = TARGET_EXPR_SLOT (allocate_expr);
TARGET_EXPR_CLEANUP (allocate_expr) = do_free_exception (ptr);
CLEANUP_EH_ONLY (allocate_expr) = 1;
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
to favor move constructors over copy constructors. */
if (/* Must be a local, automatic variable. */
TREE_CODE (exp) == VAR_DECL
&& DECL_CONTEXT (exp) == current_function_decl
&& ! TREE_STATIC (exp)
/* The variable must not have the `volatile' qualifier. */
&& !(cp_type_quals (TREE_TYPE (exp)) & TYPE_QUAL_VOLATILE))
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, &exp_vec,
TREE_TYPE (object), flags, tf_warning_or_error));
release_tree_vector (exp_vec);
if (exp == error_mark_node)
{
error (" in thrown expression");
return error_mark_node;
}
}
else
{
tmp = decay_conversion (exp, tf_warning_or_error);
if (tmp == error_mark_node)
return error_mark_node;
exp = build2 (INIT_EXPR, temp_type, object, tmp);
}
/* 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);
/* 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)));
if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (object)))
{
cleanup = lookup_fnfields (TYPE_BINFO (TREE_TYPE (object)),
complete_dtor_identifier, 0);
cleanup = BASELINK_FUNCTIONS (cleanup);
mark_used (cleanup);
cxx_mark_addressable (cleanup);
/* Pretend it's a normal function. */
cleanup = build1 (ADDR_EXPR, cleanup_type, cleanup);
}
else
cleanup = build_int_cst (cleanup_type, 0);
/* ??? Indicate that this function call throws throw_type. */
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);
}
else
{
/* Rethrow current exception. */
tree fn = get_identifier ("__cxa_rethrow");
if (!get_global_value_if_present (fn, &fn))
{
/* Declare void __cxa_rethrow (void). */
fn = push_throw_library_fn
(fn, build_function_type_list (void_type_node, NULL_TREE));
}
if (flag_tm)
apply_tm_attr (fn, get_identifier ("transaction_pure"));
/* ??? Indicate that this function call allows exceptions of the type
of the enclosing catch block (if known). */
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;
}
/* Make sure TYPE is complete, pointer to complete, reference to
complete, or pointer to cv void. Issue diagnostic on failure.
Return the zero on failure and nonzero on success. FROM can be
the expr or decl from whence TYPE came, if available. */
static int
complete_ptr_ref_or_void_ptr_p (tree type, tree from)
{
int is_ptr;
/* Check complete. */
type = complete_type_or_else (type, from);
if (!type)
return 0;
/* Or a pointer or ref to one, or cv void *. */
is_ptr = TREE_CODE (type) == POINTER_TYPE;
if (is_ptr || TREE_CODE (type) == REFERENCE_TYPE)
{
tree core = TREE_TYPE (type);
if (is_ptr && VOID_TYPE_P (core))
/* OK */;
else if (!complete_type_or_else (core, from))
return 0;
}
return 1;
}
/* If IS_THROW is true return truth-value if T is an expression admissible
in throw-expression, i.e. if it is not of incomplete type or a pointer/
reference to such a type or of an abstract class type.
If IS_THROW is false, likewise for a catch parameter, same requirements
for its type plus rvalue reference type is also not admissible. */
static bool
is_admissible_throw_operand_or_catch_parameter (tree t, bool is_throw)
{
tree expr = is_throw ? t : NULL_TREE;
tree type = TREE_TYPE (t);
/* C++11 [except.handle] The exception-declaration shall not denote
an incomplete type, an abstract class type, or an rvalue reference
type. */
/* 15.1/4 [...] The type of the throw-expression shall not be an
incomplete type, or a pointer or a reference to an incomplete
type, other than void*, const void*, volatile void*, or
const volatile void*. Except for these restriction and the
restrictions on type matching mentioned in 15.3, the operand
of throw is treated exactly as a function argument in a call
(5.2.2) or the operand of a return statement. */
if (!complete_ptr_ref_or_void_ptr_p (type, expr))
return false;
/* 10.4/3 An abstract class shall not be used as a parameter type,
as a function return type or as type of an explicit
conversion. */
else if (ABSTRACT_CLASS_TYPE_P (type))
{
if (is_throw)
error ("expression %qE of abstract class type %qT cannot "
"be used in throw-expression", expr, type);
else
error ("cannot declare catch parameter to be of abstract "
"class type %qT", type);
return false;
}
else if (!is_throw
&& TREE_CODE (type) == REFERENCE_TYPE
&& TYPE_REF_IS_RVALUE (type))
{
error ("cannot declare catch parameter to be of rvalue "
"reference type %qT", type);
return false;
}
return true;
}
/* Returns nonzero if FN is a declaration of a standard C library