Mercurial > illumos > illumos-gate
annotate usr/src/lib/libc/port/unwind/unwind.c @ 13726:056b82d21d71
1450 Illumos should be buildable with GCC4
Reviewed by: Joshua M. Clulow <josh@sysmgr.org>
Reviewed by: Keith Wesolowski <keith.wesolowski@joyent.com>
Reviewed by: Gordon Ross <gwr@nexenta.com>
Reviewed by: Albert Lee <trisk@nexenta.com>
Approved by: Gordon Ross <gwr@nexenta.com>
| author | Richard Lowe <richlowe@richlowe.net> |
|---|---|
| date | Sat, 14 Apr 2012 20:29:22 -0400 |
| parents | febeba71273d |
| children |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 * CDDL HEADER START | |
| 3 * | |
| 4 * The contents of this file are subject to the terms of the | |
| 6812 | 5 * Common Development and Distribution License (the "License"). |
| 6 * You may not use this file except in compliance with the License. | |
| 0 | 7 * |
| 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE | |
| 9 * or http://www.opensolaris.org/os/licensing. | |
| 10 * See the License for the specific language governing permissions | |
| 11 * and limitations under the License. | |
| 12 * | |
| 13 * When distributing Covered Code, include this CDDL HEADER in each | |
| 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. | |
| 15 * If applicable, add the following below this CDDL HEADER, with the | |
| 16 * fields enclosed by brackets "[]" replaced with your own identifying | |
| 17 * information: Portions Copyright [yyyy] [name of copyright owner] | |
| 18 * | |
| 19 * CDDL HEADER END | |
| 20 */ | |
| 1219 | 21 |
| 0 | 22 /* |
| 6812 | 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. |
| 0 | 24 * Use is subject to license terms. |
| 25 */ | |
| 26 | |
| 6812 | 27 #include "lint.h" |
| 0 | 28 #include "thr_uberdata.h" |
| 29 #include <dlfcn.h> | |
| 30 | |
| 31 /* | |
| 32 * This is common code for sparc, sparcv9, and i386. | |
| 33 * The amd64 unwind code is vastly different from this. | |
| 34 * Look under the amd64-specific directory structure for details. | |
| 35 */ | |
| 36 | |
| 37 /* | |
| 38 * _ex_unwind() is provided by libC, but if libC is not loaded we | |
| 39 * need to call a local version of _ex_unwind() which does exactly | |
| 40 * the same thing except for calling C++ destructors. | |
|
13726
056b82d21d71
1450 Illumos should be buildable with GCC4
Richard Lowe <richlowe@richlowe.net>
parents:
6812
diff
changeset
|
41 * |
|
056b82d21d71
1450 Illumos should be buildable with GCC4
Richard Lowe <richlowe@richlowe.net>
parents:
6812
diff
changeset
|
42 * Note that neither of these literally "returns twice" as, for eg, setjmp |
|
056b82d21d71
1450 Illumos should be buildable with GCC4
Richard Lowe <richlowe@richlowe.net>
parents:
6812
diff
changeset
|
43 * does, but they induce unusual control flow which the compiler should treat |
|
056b82d21d71
1450 Illumos should be buildable with GCC4
Richard Lowe <richlowe@richlowe.net>
parents:
6812
diff
changeset
|
44 * in the same manner (make all registers dead, etc.). |
| 0 | 45 */ |
|
13726
056b82d21d71
1450 Illumos should be buildable with GCC4
Richard Lowe <richlowe@richlowe.net>
parents:
6812
diff
changeset
|
46 extern void _ex_clnup_handler(void *, void (*)(void *)) __RETURNS_TWICE; |
|
056b82d21d71
1450 Illumos should be buildable with GCC4
Richard Lowe <richlowe@richlowe.net>
parents:
6812
diff
changeset
|
47 extern void _ex_unwind_local(void) __RETURNS_TWICE; |
| 0 | 48 #pragma unknown_control_flow(_ex_clnup_handler) |
| 49 #pragma unknown_control_flow(_ex_unwind_local) | |
| 50 | |
| 51 /* | |
| 52 * _t_cancel(fp):calls cleanup handlers if there are any in | |
| 53 * frame (fp), and calls _ex_unwind() to call | |
| 54 * destructors if libC has been linked. | |
| 55 * | |
| 56 * Control comes here from _thrp_unwind. Logically: | |
| 57 * | |
| 58 * _thrp_unwind: first arg = current fp; | |
| 59 * jump _t_cancel; | |
| 60 * | |
| 6812 | 61 * We could have called _t_cancel(_getfp) from thr_exit() |
| 0 | 62 * but _ex_unwind() also calls _t_cancel() and it does after |
| 63 * poping out the two frames. If _ex_unwind() passes the current | |
| 64 * fp, then it will be invalid. For a caller of _thrp_unwind() | |
| 65 * it looks as if it is calling _t_cancel(fp). | |
| 66 * | |
| 67 * _t_cancel will eventually call _thrp_exit(). | |
| 68 * It never returns from _t_cancel(). | |
| 69 * | |
| 70 */ | |
| 71 void | |
| 72 _t_cancel(void *fp) | |
| 73 { | |
| 74 ulwp_t *self = curthread; | |
| 75 __cleanup_t *head; | |
| 76 void (*fptr)(void (*func)(void *), void *arg); | |
| 77 | |
| 78 /* Do this once per thread exit, not once per unwind frame */ | |
| 79 if (self->ul_ex_unwind == NULL && | |
| 80 (self->ul_ex_unwind = dlsym(RTLD_PROBE, "_ex_unwind")) == NULL) | |
| 81 self->ul_ex_unwind = (void *)-1; | |
| 82 | |
| 83 if (self->ul_ex_unwind == (void *)-1) | |
| 84 fptr = NULL; | |
| 85 else | |
| 86 fptr = (void (*)())self->ul_ex_unwind; | |
| 87 | |
| 88 if (fp == NULL) { | |
| 89 _thrp_exit(); | |
| 90 thr_panic("_t_cancel(): _thrp_exit() returned"); | |
| 91 } | |
| 92 | |
| 93 if ((head = self->ul_clnup_hdr) != NULL && fp == head->fp) { | |
| 94 self->ul_clnup_hdr = head->next; | |
| 95 /* execute the cleanup handler */ | |
| 96 _ex_clnup_handler(head->arg, head->func); | |
| 97 thr_panic("_t_cancel(): _ex_clnup_handler() returned"); | |
| 98 } | |
| 99 | |
| 100 if (fptr != NULL && self->ul_unwind) { | |
| 101 /* libC is loaded and thread is canceled, call libC version */ | |
| 102 (*fptr)(_thrp_unwind, NULL); | |
| 103 thr_panic("_t_cancel(): _ex_unwind() returned"); | |
| 104 } else if (head != NULL) { | |
| 105 /* libC not present, call local version */ | |
| 106 _ex_unwind_local(); | |
| 107 thr_panic("_t_cancel(): _ex_unwind_local() returned"); | |
| 108 } else { | |
| 109 /* libC not present and no cleanup handlers, exit here */ | |
| 110 _thrp_exit(); | |
| 111 thr_panic("_t_cancel(): _thrp_exit() returned"); | |
| 112 } | |
| 113 /* never returns here */ | |
| 114 } |