mirror of
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cc1a345c65
They are very useful but at this time I prefer not to figure out some minor conflicts with the bigger Apple's blocks support patch that is being worked on for current.
999 lines
28 KiB
C
999 lines
28 KiB
C
/* Handle exceptional things in C++.
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Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
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2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
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Contributed by Michael Tiemann <tiemann@cygnus.com>
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Rewritten by Mike Stump <mrs@cygnus.com>, based upon an
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initial re-implementation courtesy Tad Hunt.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to
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the Free Software Foundation, 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "tree.h"
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#include "rtl.h"
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#include "expr.h"
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#include "libfuncs.h"
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#include "cp-tree.h"
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#include "flags.h"
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#include "output.h"
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#include "except.h"
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#include "toplev.h"
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#include "tree-inline.h"
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#include "tree-iterator.h"
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#include "target.h"
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static void push_eh_cleanup (tree);
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static tree prepare_eh_type (tree);
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static tree build_eh_type_type (tree);
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static tree do_begin_catch (void);
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static int dtor_nothrow (tree);
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static tree do_end_catch (tree);
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static bool decl_is_java_type (tree decl, int err);
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static void initialize_handler_parm (tree, tree);
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static tree do_allocate_exception (tree);
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static tree wrap_cleanups_r (tree *, int *, void *);
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static int complete_ptr_ref_or_void_ptr_p (tree, tree);
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static bool is_admissible_throw_operand (tree);
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static int can_convert_eh (tree, tree);
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static tree cp_protect_cleanup_actions (void);
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/* Sets up all the global eh stuff that needs to be initialized at the
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start of compilation. */
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void
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init_exception_processing (void)
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{
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tree tmp;
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/* void std::terminate (); */
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push_namespace (std_identifier);
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tmp = build_function_type (void_type_node, void_list_node);
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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;
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pop_namespace ();
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/* void __cxa_call_unexpected(void *); */
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tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
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tmp = build_function_type (void_type_node, tmp);
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call_unexpected_node
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= push_throw_library_fn (get_identifier ("__cxa_call_unexpected"), tmp);
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eh_personality_libfunc = init_one_libfunc (USING_SJLJ_EXCEPTIONS
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? "__gxx_personality_sj0"
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: "__gxx_personality_v0");
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if (targetm.arm_eabi_unwinder)
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unwind_resume_libfunc = init_one_libfunc ("__cxa_end_cleanup");
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else
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default_init_unwind_resume_libfunc ();
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lang_eh_runtime_type = build_eh_type_type;
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lang_protect_cleanup_actions = &cp_protect_cleanup_actions;
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}
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/* Returns an expression to be executed if an unhandled exception is
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propagated out of a cleanup region. */
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static tree
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cp_protect_cleanup_actions (void)
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{
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/* [except.terminate]
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When the destruction of an object during stack unwinding exits
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using an exception ... void terminate(); is called. */
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return build_call (terminate_node, NULL_TREE);
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}
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static tree
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prepare_eh_type (tree type)
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{
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if (type == NULL_TREE)
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return type;
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if (type == error_mark_node)
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return error_mark_node;
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/* peel back references, so they match. */
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type = non_reference (type);
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/* Peel off cv qualifiers. */
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type = TYPE_MAIN_VARIANT (type);
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return type;
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}
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/* Return the type info for TYPE as used by EH machinery. */
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tree
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eh_type_info (tree type)
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{
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tree exp;
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if (type == NULL_TREE || type == error_mark_node)
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return type;
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if (decl_is_java_type (type, 0))
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exp = build_java_class_ref (TREE_TYPE (type));
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else
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exp = get_tinfo_decl (type);
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return exp;
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}
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/* Build the address of a typeinfo decl for use in the runtime
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matching field of the exception model. */
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static tree
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build_eh_type_type (tree type)
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{
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tree exp = eh_type_info (type);
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if (!exp)
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return NULL;
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mark_used (exp);
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return convert (ptr_type_node, build_address (exp));
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}
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tree
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build_exc_ptr (void)
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{
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return build0 (EXC_PTR_EXPR, ptr_type_node);
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}
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/* Build up a call to __cxa_get_exception_ptr so that we can build a
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copy constructor for the thrown object. */
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static tree
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do_get_exception_ptr (void)
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{
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tree fn;
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fn = get_identifier ("__cxa_get_exception_ptr");
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if (!get_global_value_if_present (fn, &fn))
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{
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/* Declare void* __cxa_get_exception_ptr (void *). */
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tree tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
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fn = push_library_fn (fn, build_function_type (ptr_type_node, tmp));
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}
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return build_function_call (fn, tree_cons (NULL_TREE, build_exc_ptr (),
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NULL_TREE));
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}
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/* Build up a call to __cxa_begin_catch, to tell the runtime that the
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exception has been handled. */
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static tree
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do_begin_catch (void)
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{
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tree fn;
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fn = get_identifier ("__cxa_begin_catch");
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if (!get_global_value_if_present (fn, &fn))
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{
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/* Declare void* __cxa_begin_catch (void *). */
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tree tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
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fn = push_library_fn (fn, build_function_type (ptr_type_node, tmp));
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}
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return build_function_call (fn, tree_cons (NULL_TREE, build_exc_ptr (),
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NULL_TREE));
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}
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/* Returns nonzero if cleaning up an exception of type TYPE (which can be
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NULL_TREE for a ... handler) will not throw an exception. */
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static int
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dtor_nothrow (tree type)
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{
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if (type == NULL_TREE)
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return 0;
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if (!CLASS_TYPE_P (type))
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return 1;
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if (CLASSTYPE_LAZY_DESTRUCTOR (type))
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lazily_declare_fn (sfk_destructor, type);
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return TREE_NOTHROW (CLASSTYPE_DESTRUCTORS (type));
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}
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/* Build up a call to __cxa_end_catch, to destroy the exception object
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for the current catch block if no others are currently using it. */
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static tree
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do_end_catch (tree type)
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{
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tree fn, cleanup;
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fn = get_identifier ("__cxa_end_catch");
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if (!get_global_value_if_present (fn, &fn))
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{
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/* Declare void __cxa_end_catch (). */
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fn = push_void_library_fn (fn, void_list_node);
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/* This can throw if the destructor for the exception throws. */
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TREE_NOTHROW (fn) = 0;
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}
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cleanup = build_function_call (fn, NULL_TREE);
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TREE_NOTHROW (cleanup) = dtor_nothrow (type);
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return cleanup;
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}
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/* This routine creates the cleanup for the current exception. */
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static void
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push_eh_cleanup (tree type)
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{
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finish_decl_cleanup (NULL_TREE, do_end_catch (type));
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}
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/* Return nonzero value if DECL is a Java type suitable for catch or
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throw. */
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static bool
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decl_is_java_type (tree decl, int err)
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{
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bool r = (TREE_CODE (decl) == POINTER_TYPE
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&& TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
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&& TYPE_FOR_JAVA (TREE_TYPE (decl)));
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if (err)
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{
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if (TREE_CODE (decl) == REFERENCE_TYPE
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&& TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
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&& TYPE_FOR_JAVA (TREE_TYPE (decl)))
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{
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/* Can't throw a reference. */
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error ("type %qT is disallowed in Java %<throw%> or %<catch%>",
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decl);
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}
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if (r)
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{
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tree jthrow_node
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= IDENTIFIER_GLOBAL_VALUE (get_identifier ("jthrowable"));
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if (jthrow_node == NULL_TREE)
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fatal_error
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("call to Java %<catch%> or %<throw%> with %<jthrowable%> undefined");
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jthrow_node = TREE_TYPE (TREE_TYPE (jthrow_node));
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if (! DERIVED_FROM_P (jthrow_node, TREE_TYPE (decl)))
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{
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/* Thrown object must be a Throwable. */
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error ("type %qT is not derived from %<java::lang::Throwable%>",
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TREE_TYPE (decl));
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}
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}
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}
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return r;
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}
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/* Select the personality routine to be used for exception handling,
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or issue an error if we need two different ones in the same
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translation unit.
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??? At present eh_personality_libfunc is set to
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__gxx_personality_(sj|v)0 in init_exception_processing - should it
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be done here instead? */
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void
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choose_personality_routine (enum languages lang)
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{
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static enum {
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chose_none,
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chose_cpp,
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chose_java,
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gave_error
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} state;
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switch (state)
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{
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case gave_error:
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return;
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case chose_cpp:
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if (lang != lang_cplusplus)
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goto give_error;
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return;
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case chose_java:
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if (lang != lang_java)
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goto give_error;
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return;
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case chose_none:
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; /* Proceed to language selection. */
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}
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switch (lang)
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{
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case lang_cplusplus:
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state = chose_cpp;
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break;
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case lang_java:
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state = chose_java;
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eh_personality_libfunc = init_one_libfunc (USING_SJLJ_EXCEPTIONS
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? "__gcj_personality_sj0"
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: "__gcj_personality_v0");
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break;
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default:
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gcc_unreachable ();
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}
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return;
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give_error:
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error ("mixing C++ and Java catches in a single translation unit");
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state = gave_error;
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}
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/* Initialize the catch parameter DECL. */
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static void
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initialize_handler_parm (tree decl, tree exp)
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{
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tree init;
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tree init_type;
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/* Make sure we mark the catch param as used, otherwise we'll get a
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warning about an unused ((anonymous)). */
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TREE_USED (decl) = 1;
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/* Figure out the type that the initializer is. Pointers are returned
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adjusted by value from __cxa_begin_catch. Others are returned by
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reference. */
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init_type = TREE_TYPE (decl);
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if (!POINTER_TYPE_P (init_type))
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init_type = build_reference_type (init_type);
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choose_personality_routine (decl_is_java_type (init_type, 0)
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? lang_java : lang_cplusplus);
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/* Since pointers are passed by value, initialize a reference to
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pointer catch parm with the address of the temporary. */
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if (TREE_CODE (init_type) == REFERENCE_TYPE
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&& TYPE_PTR_P (TREE_TYPE (init_type)))
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exp = build_unary_op (ADDR_EXPR, exp, 1);
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exp = ocp_convert (init_type, exp, CONV_IMPLICIT|CONV_FORCE_TEMP, 0);
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init = convert_from_reference (exp);
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/* If the constructor for the catch parm exits via an exception, we
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must call terminate. See eh23.C. */
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if (TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl)))
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{
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/* Generate the copy constructor call directly so we can wrap it.
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See also expand_default_init. */
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init = ocp_convert (TREE_TYPE (decl), init,
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CONV_IMPLICIT|CONV_FORCE_TEMP, 0);
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init = build1 (MUST_NOT_THROW_EXPR, TREE_TYPE (init), init);
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}
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decl = pushdecl (decl);
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start_decl_1 (decl, true);
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cp_finish_decl (decl, init, /*init_const_expr_p=*/false, NULL_TREE,
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LOOKUP_ONLYCONVERTING|DIRECT_BIND);
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}
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/* Call this to start a catch block. DECL is the catch parameter. */
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tree
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expand_start_catch_block (tree decl)
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{
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tree exp;
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tree type;
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if (! doing_eh (1))
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return NULL_TREE;
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/* Make sure this declaration is reasonable. */
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if (decl && !complete_ptr_ref_or_void_ptr_p (TREE_TYPE (decl), NULL_TREE))
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decl = error_mark_node;
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if (decl)
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type = prepare_eh_type (TREE_TYPE (decl));
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else
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type = NULL_TREE;
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if (decl && decl_is_java_type (type, 1))
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{
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/* Java only passes object via pointer and doesn't require
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adjusting. The java object is immediately before the
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generic exception header. */
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exp = build_exc_ptr ();
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exp = build1 (NOP_EXPR, build_pointer_type (type), exp);
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exp = build2 (MINUS_EXPR, TREE_TYPE (exp), exp,
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TYPE_SIZE_UNIT (TREE_TYPE (exp)));
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exp = build_indirect_ref (exp, NULL);
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initialize_handler_parm (decl, exp);
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return type;
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}
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/* Call __cxa_end_catch at the end of processing the exception. */
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push_eh_cleanup (type);
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/* If there's no decl at all, then all we need to do is make sure
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to tell the runtime that we've begun handling the exception. */
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if (decl == NULL || decl == error_mark_node)
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finish_expr_stmt (do_begin_catch ());
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/* If the C++ object needs constructing, we need to do that before
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calling __cxa_begin_catch, so that std::uncaught_exception gets
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the right value during the copy constructor. */
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else if (flag_use_cxa_get_exception_ptr
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&& TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl)))
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{
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exp = do_get_exception_ptr ();
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initialize_handler_parm (decl, exp);
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finish_expr_stmt (do_begin_catch ());
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}
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/* Otherwise the type uses a bitwise copy, and we don't have to worry
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about the value of std::uncaught_exception and therefore can do the
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copy with the return value of __cxa_end_catch instead. */
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else
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{
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tree init = do_begin_catch ();
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tree init_type = type;
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/* Pointers are passed by values, everything else by reference. */
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if (!TYPE_PTR_P (type))
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init_type = build_pointer_type (type);
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if (init_type != TREE_TYPE (init))
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init = build1 (NOP_EXPR, init_type, init);
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exp = create_temporary_var (init_type);
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DECL_REGISTER (exp) = 1;
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cp_finish_decl (exp, init, /*init_const_expr=*/false,
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NULL_TREE, LOOKUP_ONLYCONVERTING);
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initialize_handler_parm (decl, exp);
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}
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return type;
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}
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/* Call this to end a catch block. Its responsible for emitting the
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code to handle jumping back to the correct place, and for emitting
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the label to jump to if this catch block didn't match. */
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void
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expand_end_catch_block (void)
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{
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if (! doing_eh (1))
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return;
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/* The exception being handled is rethrown if control reaches the end of
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a handler of the function-try-block of a constructor or destructor. */
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if (in_function_try_handler
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&& (DECL_CONSTRUCTOR_P (current_function_decl)
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|| DECL_DESTRUCTOR_P (current_function_decl)))
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finish_expr_stmt (build_throw (NULL_TREE));
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}
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tree
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begin_eh_spec_block (void)
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{
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tree r = build_stmt (EH_SPEC_BLOCK, NULL_TREE, NULL_TREE);
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add_stmt (r);
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EH_SPEC_STMTS (r) = push_stmt_list ();
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return r;
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}
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void
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finish_eh_spec_block (tree raw_raises, tree eh_spec_block)
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{
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tree raises;
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EH_SPEC_STMTS (eh_spec_block) = pop_stmt_list (EH_SPEC_STMTS (eh_spec_block));
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/* Strip cv quals, etc, from the specification types. */
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for (raises = NULL_TREE;
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raw_raises && TREE_VALUE (raw_raises);
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raw_raises = TREE_CHAIN (raw_raises))
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{
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tree type = prepare_eh_type (TREE_VALUE (raw_raises));
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tree tinfo = eh_type_info (type);
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mark_used (tinfo);
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raises = tree_cons (NULL_TREE, type, raises);
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}
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|
|
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). */
|
|
tree tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
|
|
fn = push_library_fn (fn, build_function_type (ptr_type_node, tmp));
|
|
}
|
|
|
|
return build_function_call (fn, tree_cons (NULL_TREE, 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 *). */
|
|
fn = push_void_library_fn (fn, tree_cons (NULL_TREE, ptr_type_node,
|
|
void_list_node));
|
|
}
|
|
|
|
return build_function_call (fn, tree_cons (NULL_TREE, 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 (1))
|
|
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 = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
|
|
tmp = build_function_type (ptr_type_node, tmp);
|
|
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 = build_function_call (fn, tree_cons (NULL_TREE, exp, NULL_TREE));
|
|
}
|
|
else if (exp)
|
|
{
|
|
tree throw_type;
|
|
tree temp_type;
|
|
tree cleanup;
|
|
tree object, ptr;
|
|
tree tmp;
|
|
tree temp_expr, allocate_expr;
|
|
bool elided;
|
|
|
|
/* 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);
|
|
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 = 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);
|
|
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 (TYPE_MAIN_VARIANT (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);
|
|
object = build_nop (build_pointer_type (temp_type), ptr);
|
|
object = build_indirect_ref (object, NULL);
|
|
|
|
elided = (TREE_CODE (exp) == TARGET_EXPR);
|
|
|
|
/* And initialize the exception object. */
|
|
if (CLASS_TYPE_P (temp_type))
|
|
{
|
|
/* Call the copy constructor. */
|
|
exp = (build_special_member_call
|
|
(object, complete_ctor_identifier,
|
|
build_tree_list (NULL_TREE, exp),
|
|
TREE_TYPE (object),
|
|
LOOKUP_NORMAL | LOOKUP_ONLYCONVERTING));
|
|
if (exp == error_mark_node)
|
|
{
|
|
error (" in thrown expression");
|
|
return error_mark_node;
|
|
}
|
|
}
|
|
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);
|
|
|
|
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);
|
|
|
|
/* 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. */
|
|
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);
|
|
}
|
|
|
|
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);
|
|
|
|
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 = build_function_call (fn, tmp);
|
|
|
|
/* 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 (void_type_node, void_list_node));
|
|
}
|
|
|
|
/* ??? Indicate that this function call allows exceptions of the type
|
|
of the enclosing catch block (if known). */
|
|
exp = build_function_call (fn, NULL_TREE);
|
|
}
|
|
|
|
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 (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 (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);
|
|
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)
|
|
pedwarn ("%H%<...%> handler must be the last handler for"
|
|
" its try block", EXPR_LOCUS (handler));
|
|
else
|
|
check_handlers_1 (handler, i);
|
|
}
|
|
}
|