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Diffstat (limited to 'libgcc/unwind-sjlj.c')
| -rw-r--r-- | libgcc/unwind-sjlj.c | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/libgcc/unwind-sjlj.c b/libgcc/unwind-sjlj.c new file mode 100644 index 00000000000..c71e79858ee --- /dev/null +++ b/libgcc/unwind-sjlj.c @@ -0,0 +1,326 @@ +/* SJLJ exception handling and frame unwind runtime interface routines. + Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2006, + 2009 Free Software Foundation, Inc. + + 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. + + Under Section 7 of GPL version 3, you are granted additional + permissions described in the GCC Runtime Library Exception, version + 3.1, as published by the Free Software Foundation. + + You should have received a copy of the GNU General Public License and + a copy of the GCC Runtime Library Exception along with this program; + see the files COPYING3 and COPYING.RUNTIME respectively. If not, see + <http://www.gnu.org/licenses/>. */ + +#include "tconfig.h" +#include "tsystem.h" +#include "coretypes.h" +#include "tm.h" +#include "unwind.h" +#include "gthr.h" + +#ifdef __USING_SJLJ_EXCEPTIONS__ + +#ifdef DONT_USE_BUILTIN_SETJMP +#ifndef inhibit_libc +#include <setjmp.h> +#else +typedef void *jmp_buf[JMP_BUF_SIZE]; +extern void longjmp(jmp_buf, int) __attribute__((noreturn)); +#endif +#else +#define longjmp __builtin_longjmp +#endif + +/* The setjmp side is dealt with in the except.c file. */ +#undef setjmp +#define setjmp setjmp_should_not_be_used_in_this_file + + +/* This structure is allocated on the stack of the target function. + This must match the definition created in except.c:init_eh. */ +struct SjLj_Function_Context +{ + /* This is the chain through all registered contexts. It is + filled in by _Unwind_SjLj_Register. */ + struct SjLj_Function_Context *prev; + + /* This is assigned in by the target function before every call + to the index of the call site in the lsda. It is assigned by + the personality routine to the landing pad index. */ + int call_site; + + /* This is how data is returned from the personality routine to + the target function's handler. */ + _Unwind_Word data[4]; + + /* These are filled in once by the target function before any + exceptions are expected to be handled. */ + _Unwind_Personality_Fn personality; + void *lsda; + +#ifdef DONT_USE_BUILTIN_SETJMP + /* We don't know what sort of alignment requirements the system + jmp_buf has. We over estimated in except.c, and now we have + to match that here just in case the system *didn't* have more + restrictive requirements. */ + jmp_buf jbuf __attribute__((aligned)); +#else + void *jbuf[]; +#endif +}; + +struct _Unwind_Context +{ + struct SjLj_Function_Context *fc; +}; + +typedef struct +{ + _Unwind_Personality_Fn personality; +} _Unwind_FrameState; + + +/* Manage the chain of registered function contexts. */ + +/* Single threaded fallback chain. */ +static struct SjLj_Function_Context *fc_static; + +#if __GTHREADS +static __gthread_key_t fc_key; +static int use_fc_key = -1; + +static void +fc_key_init (void) +{ + use_fc_key = __gthread_key_create (&fc_key, 0) == 0; +} + +static void +fc_key_init_once (void) +{ + static __gthread_once_t once = __GTHREAD_ONCE_INIT; + if (__gthread_once (&once, fc_key_init) != 0 || use_fc_key < 0) + use_fc_key = 0; +} +#endif + +void +_Unwind_SjLj_Register (struct SjLj_Function_Context *fc) +{ +#if __GTHREADS + if (use_fc_key < 0) + fc_key_init_once (); + + if (use_fc_key) + { + fc->prev = __gthread_getspecific (fc_key); + __gthread_setspecific (fc_key, fc); + } + else +#endif + { + fc->prev = fc_static; + fc_static = fc; + } +} + +static inline struct SjLj_Function_Context * +_Unwind_SjLj_GetContext (void) +{ +#if __GTHREADS + if (use_fc_key < 0) + fc_key_init_once (); + + if (use_fc_key) + return __gthread_getspecific (fc_key); +#endif + return fc_static; +} + +static inline void +_Unwind_SjLj_SetContext (struct SjLj_Function_Context *fc) +{ +#if __GTHREADS + if (use_fc_key < 0) + fc_key_init_once (); + + if (use_fc_key) + __gthread_setspecific (fc_key, fc); + else +#endif + fc_static = fc; +} + +void +_Unwind_SjLj_Unregister (struct SjLj_Function_Context *fc) +{ + _Unwind_SjLj_SetContext (fc->prev); +} + + +/* Get/set the return data value at INDEX in CONTEXT. */ + +_Unwind_Word +_Unwind_GetGR (struct _Unwind_Context *context, int index) +{ + return context->fc->data[index]; +} + +/* Get the value of the CFA as saved in CONTEXT. */ + +_Unwind_Word +_Unwind_GetCFA (struct _Unwind_Context *context __attribute__((unused))) +{ + /* ??? Ideally __builtin_setjmp places the CFA in the jmpbuf. */ + +#ifndef DONT_USE_BUILTIN_SETJMP + /* This is a crude imitation of the CFA: the saved stack pointer. + This is roughly the CFA of the frame before CONTEXT. When using the + DWARF-2 unwinder _Unwind_GetCFA returns the CFA of the frame described + by CONTEXT instead; but for DWARF-2 the cleanups associated with + CONTEXT have already been run, and for SJLJ they have not yet been. */ + if (context->fc != NULL) + return (_Unwind_Word) context->fc->jbuf[2]; +#endif + + /* Otherwise we're out of luck for now. */ + return (_Unwind_Word) 0; +} + +void +_Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val) +{ + context->fc->data[index] = val; +} + +/* Get the call-site index as saved in CONTEXT. */ + +_Unwind_Ptr +_Unwind_GetIP (struct _Unwind_Context *context) +{ + return context->fc->call_site + 1; +} + +_Unwind_Ptr +_Unwind_GetIPInfo (struct _Unwind_Context *context, int *ip_before_insn) +{ + *ip_before_insn = 0; + if (context->fc != NULL) + return context->fc->call_site + 1; + else + return 0; +} + +/* Set the return landing pad index in CONTEXT. */ + +void +_Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val) +{ + context->fc->call_site = val - 1; +} + +void * +_Unwind_GetLanguageSpecificData (struct _Unwind_Context *context) +{ + return context->fc->lsda; +} + +_Unwind_Ptr +_Unwind_GetRegionStart (struct _Unwind_Context *context __attribute__((unused)) ) +{ + return 0; +} + +void * +_Unwind_FindEnclosingFunction (void *pc __attribute__((unused))) +{ + return NULL; +} + +#ifndef __ia64__ +_Unwind_Ptr +_Unwind_GetDataRelBase (struct _Unwind_Context *context __attribute__((unused)) ) +{ + return 0; +} + +_Unwind_Ptr +_Unwind_GetTextRelBase (struct _Unwind_Context *context __attribute__((unused)) ) +{ + return 0; +} +#endif + +static inline _Unwind_Reason_Code +uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs) +{ + if (context->fc == NULL) + { + fs->personality = NULL; + return _URC_END_OF_STACK; + } + else + { + fs->personality = context->fc->personality; + return _URC_NO_REASON; + } +} + +static inline void +uw_update_context (struct _Unwind_Context *context, + _Unwind_FrameState *fs __attribute__((unused)) ) +{ + context->fc = context->fc->prev; +} + +static void +uw_advance_context (struct _Unwind_Context *context, _Unwind_FrameState *fs) +{ + _Unwind_SjLj_Unregister (context->fc); + uw_update_context (context, fs); +} + +static inline void +uw_init_context (struct _Unwind_Context *context) +{ + context->fc = _Unwind_SjLj_GetContext (); +} + +static void __attribute__((noreturn)) +uw_install_context (struct _Unwind_Context *current __attribute__((unused)), + struct _Unwind_Context *target) +{ + _Unwind_SjLj_SetContext (target->fc); + longjmp (target->fc->jbuf, 1); +} + +static inline _Unwind_Ptr +uw_identify_context (struct _Unwind_Context *context) +{ + return (_Unwind_Ptr) context->fc; +} + + +/* Play games with unwind symbols so that we can have call frame + and sjlj symbols in the same shared library. Not that you can + use them simultaneously... */ +#define _Unwind_RaiseException _Unwind_SjLj_RaiseException +#define _Unwind_ForcedUnwind _Unwind_SjLj_ForcedUnwind +#define _Unwind_Resume _Unwind_SjLj_Resume +#define _Unwind_Resume_or_Rethrow _Unwind_SjLj_Resume_or_Rethrow + +#include "unwind.inc" + +#endif /* USING_SJLJ_EXCEPTIONS */ |