1/* SJLJ exception handling and frame unwind runtime interface routines. 2 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 3 Free Software Foundation, Inc. 4 5 This file is part of GCC. 6 7 GCC is free software; you can redistribute it and/or modify it 8 under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 2, or (at your option) 10 any later version. 11 12 In addition to the permissions in the GNU General Public License, the 13 Free Software Foundation gives you unlimited permission to link the 14 compiled version of this file into combinations with other programs, 15 and to distribute those combinations without any restriction coming 16 from the use of this file. (The General Public License restrictions 17 do apply in other respects; for example, they cover modification of 18 the file, and distribution when not linked into a combined 19 executable.) 20 21 GCC is distributed in the hope that it will be useful, but WITHOUT 22 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 23 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public 24 License for more details. 25 26 You should have received a copy of the GNU General Public License 27 along with GCC; see the file COPYING. If not, write to the Free 28 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 29 02110-1301, USA. */ 30 31#include "tconfig.h" 32#include "tsystem.h" 33#include "coretypes.h" 34#include "tm.h" 35#include "unwind.h" 36#include "gthr.h" 37 38#ifdef __USING_SJLJ_EXCEPTIONS__ 39 40#ifdef DONT_USE_BUILTIN_SETJMP 41#ifndef inhibit_libc 42#include <setjmp.h> 43#else 44typedef void *jmp_buf[JMP_BUF_SIZE]; 45extern void longjmp(jmp_buf, int) __attribute__((noreturn)); 46#endif 47#else 48#define setjmp __builtin_setjmp 49#define longjmp __builtin_longjmp 50#endif 51 52/* This structure is allocated on the stack of the target function. 53 This must match the definition created in except.c:init_eh. */ 54struct SjLj_Function_Context 55{ 56 /* This is the chain through all registered contexts. It is 57 filled in by _Unwind_SjLj_Register. */ 58 struct SjLj_Function_Context *prev; 59 60 /* This is assigned in by the target function before every call 61 to the index of the call site in the lsda. It is assigned by 62 the personality routine to the landing pad index. */ 63 int call_site; 64 65 /* This is how data is returned from the personality routine to 66 the target function's handler. */ 67 _Unwind_Word data[4]; 68 69 /* These are filled in once by the target function before any 70 exceptions are expected to be handled. */ 71 _Unwind_Personality_Fn personality; 72 void *lsda; 73 74#ifdef DONT_USE_BUILTIN_SETJMP 75 /* We don't know what sort of alignment requirements the system 76 jmp_buf has. We over estimated in except.c, and now we have 77 to match that here just in case the system *didn't* have more 78 restrictive requirements. */ 79 jmp_buf jbuf __attribute__((aligned)); 80#else 81 void *jbuf[]; 82#endif 83}; 84 85struct _Unwind_Context 86{ 87 struct SjLj_Function_Context *fc; 88}; 89 90typedef struct 91{ 92 _Unwind_Personality_Fn personality; 93} _Unwind_FrameState; 94 95 96/* Manage the chain of registered function contexts. */ 97 98/* Single threaded fallback chain. */ 99static struct SjLj_Function_Context *fc_static; 100 101#if __GTHREADS 102static __gthread_key_t fc_key; 103static int use_fc_key = -1; 104 105static void 106fc_key_init (void) 107{ 108 use_fc_key = __gthread_key_create (&fc_key, 0) == 0; 109} 110 111static void 112fc_key_init_once (void) 113{ 114 static __gthread_once_t once = __GTHREAD_ONCE_INIT; 115 if (__gthread_once (&once, fc_key_init) != 0 || use_fc_key < 0) 116 use_fc_key = 0; 117} 118#endif 119 120void 121_Unwind_SjLj_Register (struct SjLj_Function_Context *fc) 122{ 123#if __GTHREADS 124 if (use_fc_key < 0) 125 fc_key_init_once (); 126 127 if (use_fc_key) 128 { 129 fc->prev = __gthread_getspecific (fc_key); 130 __gthread_setspecific (fc_key, fc); 131 } 132 else 133#endif 134 { 135 fc->prev = fc_static; 136 fc_static = fc; 137 } 138} 139 140static inline struct SjLj_Function_Context * 141_Unwind_SjLj_GetContext (void) 142{ 143#if __GTHREADS 144 if (use_fc_key < 0) 145 fc_key_init_once (); 146 147 if (use_fc_key) 148 return __gthread_getspecific (fc_key); 149#endif 150 return fc_static; 151} 152 153static inline void 154_Unwind_SjLj_SetContext (struct SjLj_Function_Context *fc) 155{ 156#if __GTHREADS 157 if (use_fc_key < 0) 158 fc_key_init_once (); 159 160 if (use_fc_key) 161 __gthread_setspecific (fc_key, fc); 162 else 163#endif 164 fc_static = fc; 165} 166 167void 168_Unwind_SjLj_Unregister (struct SjLj_Function_Context *fc) 169{ 170 _Unwind_SjLj_SetContext (fc->prev); 171} 172 173 174/* Get/set the return data value at INDEX in CONTEXT. */ 175 176_Unwind_Word 177_Unwind_GetGR (struct _Unwind_Context *context, int index) 178{ 179 return context->fc->data[index]; 180} 181 182/* Get the value of the CFA as saved in CONTEXT. */ 183 184_Unwind_Word 185_Unwind_GetCFA (struct _Unwind_Context *context __attribute__((unused))) 186{ 187 /* ??? Ideally __builtin_setjmp places the CFA in the jmpbuf. */ 188 189#ifndef DONT_USE_BUILTIN_SETJMP 190 /* This is a crude imitation of the CFA: the saved stack pointer. 191 This is roughly the CFA of the frame before CONTEXT. When using the 192 DWARF-2 unwinder _Unwind_GetCFA returns the CFA of the frame described 193 by CONTEXT instead; but for DWARF-2 the cleanups associated with 194 CONTEXT have already been run, and for SJLJ they have not yet been. */ 195 if (context->fc != NULL) 196 return (_Unwind_Word) context->fc->jbuf[2]; 197#endif 198 199 /* Otherwise we're out of luck for now. */ 200 return (_Unwind_Word) 0; 201} 202 203void 204_Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val) 205{ 206 context->fc->data[index] = val; 207} 208 209/* Get the call-site index as saved in CONTEXT. */ 210 211_Unwind_Ptr 212_Unwind_GetIP (struct _Unwind_Context *context) 213{ 214 return context->fc->call_site + 1; 215} 216 217/* Set the return landing pad index in CONTEXT. */ 218 219void 220_Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val) 221{ 222 context->fc->call_site = val - 1; 223} 224 225void * 226_Unwind_GetLanguageSpecificData (struct _Unwind_Context *context) 227{ 228 return context->fc->lsda; 229} 230 231_Unwind_Ptr 232_Unwind_GetRegionStart (struct _Unwind_Context *context __attribute__((unused)) ) 233{ 234 return 0; 235} 236 237void * 238_Unwind_FindEnclosingFunction (void *pc __attribute__((unused))) 239{ 240 return NULL; 241} 242 243#ifndef __ia64__ 244_Unwind_Ptr 245_Unwind_GetDataRelBase (struct _Unwind_Context *context __attribute__((unused)) ) 246{ 247 return 0; 248} 249 250_Unwind_Ptr 251_Unwind_GetTextRelBase (struct _Unwind_Context *context __attribute__((unused)) ) 252{ 253 return 0; 254} 255#endif 256 257static inline _Unwind_Reason_Code 258uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs) 259{ 260 if (context->fc == NULL) 261 { 262 fs->personality = NULL; 263 return _URC_END_OF_STACK; 264 } 265 else 266 { 267 fs->personality = context->fc->personality; 268 return _URC_NO_REASON; 269 } 270} 271 272static inline void 273uw_update_context (struct _Unwind_Context *context, 274 _Unwind_FrameState *fs __attribute__((unused)) ) 275{ 276 context->fc = context->fc->prev; 277} 278 279static void 280uw_advance_context (struct _Unwind_Context *context, _Unwind_FrameState *fs) 281{ 282 _Unwind_SjLj_Unregister (context->fc); 283 uw_update_context (context, fs); 284} 285 286static inline void 287uw_init_context (struct _Unwind_Context *context) 288{ 289 context->fc = _Unwind_SjLj_GetContext (); 290} 291 292static void __attribute__((noreturn)) 293uw_install_context (struct _Unwind_Context *current __attribute__((unused)), 294 struct _Unwind_Context *target) 295{ 296 _Unwind_SjLj_SetContext (target->fc); 297 longjmp (target->fc->jbuf, 1); 298} 299 300static inline _Unwind_Ptr 301uw_identify_context (struct _Unwind_Context *context) 302{ 303 return (_Unwind_Ptr) context->fc; 304} 305 306 307/* Play games with unwind symbols so that we can have call frame 308 and sjlj symbols in the same shared library. Not that you can 309 use them simultaneously... */ 310#define _Unwind_RaiseException _Unwind_SjLj_RaiseException 311#define _Unwind_ForcedUnwind _Unwind_SjLj_ForcedUnwind 312#define _Unwind_Resume _Unwind_SjLj_Resume 313#define _Unwind_Resume_or_Rethrow _Unwind_SjLj_Resume_or_Rethrow 314 315#include "unwind.inc" 316 317#endif /* USING_SJLJ_EXCEPTIONS */ 318