1211 lines
34 KiB
C
1211 lines
34 KiB
C
/* Handle exceptional things in C++.
|
||
Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
|
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2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
|
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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 "output.h"
|
||
#include "toplev.h"
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||
#include "tree-inline.h"
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||
#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 (tree);
|
||
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);
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||
tmp = build_function_type_list (void_type_node, NULL_TREE);
|
||
terminate_node = build_cp_library_fn_ptr ("terminate", tmp);
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||
TREE_THIS_VOLATILE (terminate_node) = 1;
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||
TREE_NOTHROW (terminate_node) = 1;
|
||
pop_namespace ();
|
||
|
||
/* void __cxa_call_unexpected(void *); */
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||
tmp = build_function_type_list (void_type_node, ptr_type_node, NULL_TREE);
|
||
call_unexpected_node
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||
= 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. */
|
||
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||
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. */
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||
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
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||
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 (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
|
||
copy constructor for the thrown object. */
|
||
|
||
static tree
|
||
do_get_exception_ptr (void)
|
||
{
|
||
tree fn;
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||
|
||
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);
|
||
}
|
||
|
||
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;
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||
|
||
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);
|
||
}
|
||
|
||
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;
|
||
}
|
||
|
||
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 eh_personality_decl is set to
|
||
__gxx_personality_(sj|v)0 in init_exception_processing - 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 = built_in_decls [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;
|
||
}
|
||
|
||
/* 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_unary_op (ADDR_EXPR, exp, 1, tf_warning_or_error);
|
||
|
||
exp = ocp_convert (init_type, exp, CONV_IMPLICIT|CONV_FORCE_TEMP, 0);
|
||
|
||
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);
|
||
/* Force cleanups now to avoid nesting problems with the
|
||
MUST_NOT_THROW_EXPR. */
|
||
init = fold_build_cleanup_point_expr (TREE_TYPE (init), init);
|
||
init = build1 (MUST_NOT_THROW_EXPR, TREE_TYPE (init), init);
|
||
}
|
||
|
||
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;
|
||
|
||
/* Make sure this declaration is reasonable. */
|
||
if (decl && !complete_ptr_ref_or_void_ptr_p (TREE_TYPE (decl), NULL_TREE))
|
||
decl = error_mark_node;
|
||
|
||
if (decl)
|
||
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 = build2 (POINTER_PLUS_EXPR, TREE_TYPE (exp), 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;
|
||
/* 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);
|
||
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);
|
||
}
|
||
|
||
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 = build1 (MUST_NOT_THROW_EXPR, void_type_node, cleanup);
|
||
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;
|
||
return build_min (THROW_EXPR, void_type_node, exp);
|
||
}
|
||
|
||
if (exp == null_node)
|
||
warning (0, "throwing NULL, which has integral, not pointer type");
|
||
|
||
if (exp != NULL_TREE)
|
||
{
|
||
if (!is_admissible_throw_operand (exp))
|
||
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);
|
||
}
|
||
|
||
/* [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 = 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);
|
||
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));
|
||
}
|
||
|
||
/* ??? 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);
|
||
|
||
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;
|
||
}
|
||
|
||
/* Return truth-value if EXPRESSION is 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. */
|
||
|
||
static bool
|
||
is_admissible_throw_operand (tree expr)
|
||
{
|
||
tree type = TREE_TYPE (expr);
|
||
|
||
/* 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 (CLASS_TYPE_P (type) && CLASSTYPE_PURE_VIRTUALS (type))
|
||
{
|
||
error ("expression %qE of abstract class type %qT cannot "
|
||
"be used in throw-expression", expr, type);
|
||
return false;
|
||
}
|
||
|
||
return true;
|
||
}
|
||
|
||
/* Returns nonzero if FN is a declaration of a standard C library
|
||
function which is known not to throw.
|
||
|
||
[lib.res.on.exception.handling]: None of the functions from the
|
||
Standard C library shall report an error by throwing an
|
||
exception, unless it calls a program-supplied function that
|
||
throws an exception. */
|
||
|
||
#include "cfns.h"
|
||
|
||
int
|
||
nothrow_libfn_p (const_tree fn)
|
||
{
|
||
tree id;
|
||
|
||
if (TREE_PUBLIC (fn)
|
||
&& DECL_EXTERNAL (fn)
|
||
&& DECL_NAMESPACE_SCOPE_P (fn)
|
||
&& DECL_EXTERN_C_P (fn))
|
||
/* OK */;
|
||
else
|
||
/* Can't be a C library function. */
|
||
return 0;
|
||
|
||
/* Being a C library function, DECL_ASSEMBLER_NAME == DECL_NAME
|
||
unless the system headers are playing rename tricks, and if
|
||
they are, we don't want to be confused by them. */
|
||
id = DECL_NAME (fn);
|
||
return !!libc_name_p (IDENTIFIER_POINTER (id), IDENTIFIER_LENGTH (id));
|
||
}
|
||
|
||
/* Returns nonzero if an exception of type FROM will be caught by a
|
||
handler for type TO, as per [except.handle]. */
|
||
|
||
static int
|
||
can_convert_eh (tree to, tree from)
|
||
{
|
||
to = non_reference (to);
|
||
from = non_reference (from);
|
||
|
||
if (TREE_CODE (to) == POINTER_TYPE && TREE_CODE (from) == POINTER_TYPE)
|
||
{
|
||
to = TREE_TYPE (to);
|
||
from = TREE_TYPE (from);
|
||
|
||
if (! at_least_as_qualified_p (to, from))
|
||
return 0;
|
||
|
||
if (TREE_CODE (to) == VOID_TYPE)
|
||
return 1;
|
||
|
||
/* Else fall through. */
|
||
}
|
||
|
||
if (CLASS_TYPE_P (to) && CLASS_TYPE_P (from)
|
||
&& PUBLICLY_UNIQUELY_DERIVED_P (to, from))
|
||
return 1;
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Check whether any of the handlers in I are shadowed by another handler
|
||
accepting TYPE. Note that the shadowing may not be complete; even if
|
||
an exception of type B would be caught by a handler for A, there could
|
||
be a derived class C for which A is an ambiguous base but B is not, so
|
||
the handler for B would catch an exception of type C. */
|
||
|
||
static void
|
||
check_handlers_1 (tree master, tree_stmt_iterator i)
|
||
{
|
||
tree type = TREE_TYPE (master);
|
||
|
||
for (; !tsi_end_p (i); tsi_next (&i))
|
||
{
|
||
tree handler = tsi_stmt (i);
|
||
if (TREE_TYPE (handler) && can_convert_eh (type, TREE_TYPE (handler)))
|
||
{
|
||
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;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Given a STATEMENT_LIST of HANDLERs, make sure that they're OK. */
|
||
|
||
void
|
||
check_handlers (tree handlers)
|
||
{
|
||
tree_stmt_iterator i;
|
||
|
||
/* If we don't have a STATEMENT_LIST, then we've just got one
|
||
handler, and thus nothing to warn about. */
|
||
if (TREE_CODE (handlers) != STATEMENT_LIST)
|
||
return;
|
||
|
||
i = tsi_start (handlers);
|
||
if (!tsi_end_p (i))
|
||
while (1)
|
||
{
|
||
tree handler = tsi_stmt (i);
|
||
tsi_next (&i);
|
||
|
||
/* No more handlers; nothing to shadow. */
|
||
if (tsi_end_p (i))
|
||
break;
|
||
if (TREE_TYPE (handler) == NULL_TREE)
|
||
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)
|
||
{
|
||
/* We do use TREE_NOTHROW for ABI internals like __dynamic_cast,
|
||
and for C library functions known not to throw. */
|
||
fn = TREE_OPERAND (fn, 0);
|
||
if (TREE_CODE (fn) == FUNCTION_DECL
|
||
&& DECL_EXTERN_C_P (fn)
|
||
&& (DECL_ARTIFICIAL (fn)
|
||
|| nothrow_libfn_p (fn)))
|
||
return TREE_NOTHROW (fn) ? NULL_TREE : fn;
|
||
}
|
||
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 (i = 0;
|
||
VEC_iterate (pending_noexcept, pending_noexcept_checks, i, p);
|
||
++i)
|
||
{
|
||
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 (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)
|
||
{
|
||
expr = perform_implicit_conversion_flags (boolean_type_node, expr,
|
||
complain,
|
||
LOOKUP_NORMAL);
|
||
if (expr == boolean_true_node)
|
||
return noexcept_true_spec;
|
||
else if (expr == boolean_false_node)
|
||
return noexcept_false_spec;
|
||
else
|
||
{
|
||
gcc_assert (processing_template_decl || expr == error_mark_node);
|
||
return build_tree_list (expr, NULL_TREE);
|
||
}
|
||
}
|