compiler: add abstraction layer for sha1 checksums.
[official-gcc.git] / libgcc / unwind-c.c
blob5835aadf2321b8553698d2fcb25080542357709f
1 /* Supporting functions for C exception handling.
2 Copyright (C) 2002-2016 Free Software Foundation, Inc.
3 Contributed by Aldy Hernandez <aldy@quesejoda.com>.
4 Shamelessly stolen from the Java front end.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
18 Under Section 7 of GPL version 3, you are granted additional
19 permissions described in the GCC Runtime Library Exception, version
20 3.1, as published by the Free Software Foundation.
22 You should have received a copy of the GNU General Public License and
23 a copy of the GCC Runtime Library Exception along with this program;
24 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25 <http://www.gnu.org/licenses/>. */
27 #include "tconfig.h"
28 #include "tsystem.h"
29 #include "unwind.h"
30 #define NO_SIZE_OF_ENCODED_VALUE
31 #include "unwind-pe.h"
33 typedef struct
35 _Unwind_Ptr Start;
36 _Unwind_Ptr LPStart;
37 _Unwind_Ptr ttype_base;
38 const unsigned char *TType;
39 const unsigned char *action_table;
40 unsigned char ttype_encoding;
41 unsigned char call_site_encoding;
42 } lsda_header_info;
44 static const unsigned char *
45 parse_lsda_header (struct _Unwind_Context *context, const unsigned char *p,
46 lsda_header_info *info)
48 _uleb128_t tmp;
49 unsigned char lpstart_encoding;
51 info->Start = (context ? _Unwind_GetRegionStart (context) : 0);
53 /* Find @LPStart, the base to which landing pad offsets are relative. */
54 lpstart_encoding = *p++;
55 if (lpstart_encoding != DW_EH_PE_omit)
56 p = read_encoded_value (context, lpstart_encoding, p, &info->LPStart);
57 else
58 info->LPStart = info->Start;
60 /* Find @TType, the base of the handler and exception spec type data. */
61 info->ttype_encoding = *p++;
62 if (info->ttype_encoding != DW_EH_PE_omit)
64 p = read_uleb128 (p, &tmp);
65 info->TType = p + tmp;
67 else
68 info->TType = 0;
70 /* The encoding and length of the call-site table; the action table
71 immediately follows. */
72 info->call_site_encoding = *p++;
73 p = read_uleb128 (p, &tmp);
74 info->action_table = p + tmp;
76 return p;
79 #ifdef __ARM_EABI_UNWINDER__
80 /* ARM EABI personality routines must also unwind the stack. */
81 #define CONTINUE_UNWINDING \
82 do \
83 { \
84 if (__gnu_unwind_frame (ue_header, context) != _URC_OK) \
85 return _URC_FAILURE; \
86 return _URC_CONTINUE_UNWIND; \
87 } \
88 while (0)
89 #else
90 #define CONTINUE_UNWINDING return _URC_CONTINUE_UNWIND
91 #endif
93 #ifdef __USING_SJLJ_EXCEPTIONS__
94 #define PERSONALITY_FUNCTION __gcc_personality_sj0
95 #define __builtin_eh_return_data_regno(x) x
96 #elif defined(__SEH__)
97 #define PERSONALITY_FUNCTION __gcc_personality_imp
98 #else
99 #define PERSONALITY_FUNCTION __gcc_personality_v0
100 #endif
102 #ifdef __ARM_EABI_UNWINDER__
103 _Unwind_Reason_Code
104 PERSONALITY_FUNCTION (_Unwind_State, struct _Unwind_Exception *,
105 struct _Unwind_Context *);
107 _Unwind_Reason_Code
108 PERSONALITY_FUNCTION (_Unwind_State state,
109 struct _Unwind_Exception * ue_header,
110 struct _Unwind_Context * context)
111 #else
112 #if defined (__SEH__) && !defined (__USING_SJLJ_EXCEPTIONS__)
113 static
114 #endif
115 _Unwind_Reason_Code
116 PERSONALITY_FUNCTION (int, _Unwind_Action, _Unwind_Exception_Class,
117 struct _Unwind_Exception *, struct _Unwind_Context *);
119 _Unwind_Reason_Code
120 PERSONALITY_FUNCTION (int version,
121 _Unwind_Action actions,
122 _Unwind_Exception_Class exception_class ATTRIBUTE_UNUSED,
123 struct _Unwind_Exception *ue_header,
124 struct _Unwind_Context *context)
125 #endif
127 lsda_header_info info;
128 const unsigned char *language_specific_data, *p;
129 _Unwind_Ptr landing_pad, ip;
130 int ip_before_insn = 0;
132 #ifdef __ARM_EABI_UNWINDER__
133 if ((state & _US_ACTION_MASK) != _US_UNWIND_FRAME_STARTING)
134 CONTINUE_UNWINDING;
136 /* The dwarf unwinder assumes the context structure holds things like the
137 function and LSDA pointers. The ARM implementation caches these in
138 the exception header (UCB). To avoid rewriting everything we make a
139 virtual scratch register point at the UCB. */
140 ip = (_Unwind_Ptr) ue_header;
141 _Unwind_SetGR (context, UNWIND_POINTER_REG, ip);
142 #else
143 if (version != 1)
144 return _URC_FATAL_PHASE1_ERROR;
146 /* Currently we only support cleanups for C. */
147 if ((actions & _UA_CLEANUP_PHASE) == 0)
148 CONTINUE_UNWINDING;
149 #endif
151 language_specific_data = (const unsigned char *)
152 _Unwind_GetLanguageSpecificData (context);
154 /* If no LSDA, then there are no handlers or cleanups. */
155 if (! language_specific_data)
156 CONTINUE_UNWINDING;
158 /* Parse the LSDA header. */
159 p = parse_lsda_header (context, language_specific_data, &info);
160 #ifdef HAVE_GETIPINFO
161 ip = _Unwind_GetIPInfo (context, &ip_before_insn);
162 #else
163 ip = _Unwind_GetIP (context);
164 #endif
165 if (! ip_before_insn)
166 --ip;
167 landing_pad = 0;
169 #ifdef __USING_SJLJ_EXCEPTIONS__
170 /* The given "IP" is an index into the call-site table, with two
171 exceptions -- -1 means no-action, and 0 means terminate. But
172 since we're using uleb128 values, we've not got random access
173 to the array. */
174 if ((int) ip <= 0)
175 return _URC_CONTINUE_UNWIND;
176 else
178 _uleb128_t cs_lp, cs_action;
181 p = read_uleb128 (p, &cs_lp);
182 p = read_uleb128 (p, &cs_action);
184 while (--ip);
186 /* Can never have null landing pad for sjlj -- that would have
187 been indicated by a -1 call site index. */
188 landing_pad = (_Unwind_Ptr)cs_lp + 1;
189 goto found_something;
191 #else
192 /* Search the call-site table for the action associated with this IP. */
193 while (p < info.action_table)
195 _Unwind_Ptr cs_start, cs_len, cs_lp;
196 _uleb128_t cs_action;
198 /* Note that all call-site encodings are "absolute" displacements. */
199 p = read_encoded_value (0, info.call_site_encoding, p, &cs_start);
200 p = read_encoded_value (0, info.call_site_encoding, p, &cs_len);
201 p = read_encoded_value (0, info.call_site_encoding, p, &cs_lp);
202 p = read_uleb128 (p, &cs_action);
204 /* The table is sorted, so if we've passed the ip, stop. */
205 if (ip < info.Start + cs_start)
206 p = info.action_table;
207 else if (ip < info.Start + cs_start + cs_len)
209 if (cs_lp)
210 landing_pad = info.LPStart + cs_lp;
211 goto found_something;
214 #endif
216 /* IP is not in table. No associated cleanups. */
217 /* ??? This is where C++ calls std::terminate to catch throw
218 from a destructor. */
219 CONTINUE_UNWINDING;
221 found_something:
222 if (landing_pad == 0)
224 /* IP is present, but has a null landing pad.
225 No handler to be run. */
226 CONTINUE_UNWINDING;
229 _Unwind_SetGR (context, __builtin_eh_return_data_regno (0),
230 (_Unwind_Ptr) ue_header);
231 _Unwind_SetGR (context, __builtin_eh_return_data_regno (1), 0);
232 _Unwind_SetIP (context, landing_pad);
233 return _URC_INSTALL_CONTEXT;
236 #if defined (__SEH__) && !defined (__USING_SJLJ_EXCEPTIONS__)
237 EXCEPTION_DISPOSITION
238 __gcc_personality_seh0 (PEXCEPTION_RECORD ms_exc, void *this_frame,
239 PCONTEXT ms_orig_context, PDISPATCHER_CONTEXT ms_disp)
241 return _GCC_specific_handler (ms_exc, this_frame, ms_orig_context,
242 ms_disp, __gcc_personality_imp);
244 #endif /* SEH */