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0bfa5f65 | 1 | /* Supporting functions for C exception handling. |
748086b7 | 2 | Copyright (C) 2002, 2003, 2009 Free Software Foundation, Inc. |
0bfa5f65 RH |
3 | Contributed by Aldy Hernandez <aldy@quesejoda.com>. |
4 | Shamelessly stolen from the Java front end. | |
5 | ||
6 | This file is part of GCC. | |
7 | ||
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 | |
748086b7 | 10 | Software Foundation; either version 3, or (at your option) any later |
0bfa5f65 RH |
11 | version. |
12 | ||
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. | |
17 | ||
748086b7 JJ |
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. | |
21 | ||
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/>. */ | |
0bfa5f65 RH |
26 | |
27 | #include "tconfig.h" | |
28 | #include "tsystem.h" | |
29 | #include "unwind.h" | |
333991cf | 30 | #define NO_SIZE_OF_ENCODED_VALUE |
0bfa5f65 RH |
31 | #include "unwind-pe.h" |
32 | ||
33 | typedef struct | |
34 | { | |
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; | |
43 | ||
44 | static const unsigned char * | |
45 | parse_lsda_header (struct _Unwind_Context *context, const unsigned char *p, | |
46 | lsda_header_info *info) | |
47 | { | |
f767122b | 48 | _uleb128_t tmp; |
0bfa5f65 RH |
49 | unsigned char lpstart_encoding; |
50 | ||
51 | info->Start = (context ? _Unwind_GetRegionStart (context) : 0); | |
52 | ||
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; | |
59 | ||
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) | |
63 | { | |
64 | p = read_uleb128 (p, &tmp); | |
65 | info->TType = p + tmp; | |
66 | } | |
67 | else | |
68 | info->TType = 0; | |
69 | ||
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; | |
75 | ||
76 | return p; | |
77 | } | |
78 | ||
617a1b71 PB |
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 | |
92 | ||
0bfa5f65 RH |
93 | #ifdef __USING_SJLJ_EXCEPTIONS__ |
94 | #define PERSONALITY_FUNCTION __gcc_personality_sj0 | |
95 | #define __builtin_eh_return_data_regno(x) x | |
96 | #else | |
97 | #define PERSONALITY_FUNCTION __gcc_personality_v0 | |
98 | #endif | |
0bfa5f65 | 99 | |
617a1b71 PB |
100 | #ifdef __ARM_EABI_UNWINDER__ |
101 | _Unwind_Reason_Code | |
102 | PERSONALITY_FUNCTION (_Unwind_State, struct _Unwind_Exception *, | |
103 | struct _Unwind_Context *); | |
104 | ||
105 | _Unwind_Reason_Code | |
106 | PERSONALITY_FUNCTION (_Unwind_State state, | |
107 | struct _Unwind_Exception * ue_header, | |
108 | struct _Unwind_Context * context) | |
109 | #else | |
0bfa5f65 RH |
110 | _Unwind_Reason_Code |
111 | PERSONALITY_FUNCTION (int, _Unwind_Action, _Unwind_Exception_Class, | |
112 | struct _Unwind_Exception *, struct _Unwind_Context *); | |
113 | ||
114 | _Unwind_Reason_Code | |
115 | PERSONALITY_FUNCTION (int version, | |
116 | _Unwind_Action actions, | |
117 | _Unwind_Exception_Class exception_class ATTRIBUTE_UNUSED, | |
118 | struct _Unwind_Exception *ue_header, | |
119 | struct _Unwind_Context *context) | |
617a1b71 | 120 | #endif |
0bfa5f65 RH |
121 | { |
122 | lsda_header_info info; | |
f1ed99cd | 123 | const unsigned char *language_specific_data, *p; |
0bfa5f65 | 124 | _Unwind_Ptr landing_pad, ip; |
754e45a8 | 125 | int ip_before_insn = 0; |
0bfa5f65 | 126 | |
617a1b71 | 127 | #ifdef __ARM_EABI_UNWINDER__ |
74d9c39f | 128 | if ((state & _US_ACTION_MASK) != _US_UNWIND_FRAME_STARTING) |
617a1b71 PB |
129 | CONTINUE_UNWINDING; |
130 | ||
131 | /* The dwarf unwinder assumes the context structure holds things like the | |
132 | function and LSDA pointers. The ARM implementation caches these in | |
133 | the exception header (UCB). To avoid rewriting everything we make the | |
134 | virtual IP register point at the UCB. */ | |
135 | ip = (_Unwind_Ptr) ue_header; | |
136 | _Unwind_SetGR (context, 12, ip); | |
137 | #else | |
0bfa5f65 RH |
138 | if (version != 1) |
139 | return _URC_FATAL_PHASE1_ERROR; | |
140 | ||
141 | /* Currently we only support cleanups for C. */ | |
142 | if ((actions & _UA_CLEANUP_PHASE) == 0) | |
617a1b71 PB |
143 | CONTINUE_UNWINDING; |
144 | #endif | |
0bfa5f65 RH |
145 | |
146 | language_specific_data = (const unsigned char *) | |
147 | _Unwind_GetLanguageSpecificData (context); | |
148 | ||
149 | /* If no LSDA, then there are no handlers or cleanups. */ | |
150 | if (! language_specific_data) | |
617a1b71 | 151 | CONTINUE_UNWINDING; |
0bfa5f65 RH |
152 | |
153 | /* Parse the LSDA header. */ | |
154 | p = parse_lsda_header (context, language_specific_data, &info); | |
e64f5acf | 155 | #ifdef HAVE_GETIPINFO |
754e45a8 | 156 | ip = _Unwind_GetIPInfo (context, &ip_before_insn); |
e64f5acf SE |
157 | #else |
158 | ip = _Unwind_GetIP (context); | |
159 | #endif | |
754e45a8 JJ |
160 | if (! ip_before_insn) |
161 | --ip; | |
0bfa5f65 RH |
162 | landing_pad = 0; |
163 | ||
164 | #ifdef __USING_SJLJ_EXCEPTIONS__ | |
165 | /* The given "IP" is an index into the call-site table, with two | |
166 | exceptions -- -1 means no-action, and 0 means terminate. But | |
167 | since we're using uleb128 values, we've not got random access | |
168 | to the array. */ | |
169 | if ((int) ip <= 0) | |
170 | return _URC_CONTINUE_UNWIND; | |
171 | else | |
172 | { | |
f767122b | 173 | _uleb128_t cs_lp, cs_action; |
0bfa5f65 RH |
174 | do |
175 | { | |
176 | p = read_uleb128 (p, &cs_lp); | |
177 | p = read_uleb128 (p, &cs_action); | |
178 | } | |
179 | while (--ip); | |
180 | ||
181 | /* Can never have null landing pad for sjlj -- that would have | |
182 | been indicated by a -1 call site index. */ | |
f767122b | 183 | landing_pad = (_Unwind_Ptr)cs_lp + 1; |
0bfa5f65 RH |
184 | goto found_something; |
185 | } | |
186 | #else | |
187 | /* Search the call-site table for the action associated with this IP. */ | |
188 | while (p < info.action_table) | |
189 | { | |
190 | _Unwind_Ptr cs_start, cs_len, cs_lp; | |
f767122b | 191 | _uleb128_t cs_action; |
0bfa5f65 RH |
192 | |
193 | /* Note that all call-site encodings are "absolute" displacements. */ | |
194 | p = read_encoded_value (0, info.call_site_encoding, p, &cs_start); | |
195 | p = read_encoded_value (0, info.call_site_encoding, p, &cs_len); | |
196 | p = read_encoded_value (0, info.call_site_encoding, p, &cs_lp); | |
197 | p = read_uleb128 (p, &cs_action); | |
198 | ||
199 | /* The table is sorted, so if we've passed the ip, stop. */ | |
200 | if (ip < info.Start + cs_start) | |
201 | p = info.action_table; | |
202 | else if (ip < info.Start + cs_start + cs_len) | |
203 | { | |
204 | if (cs_lp) | |
205 | landing_pad = info.LPStart + cs_lp; | |
0bfa5f65 RH |
206 | goto found_something; |
207 | } | |
208 | } | |
0bfa5f65 RH |
209 | #endif |
210 | ||
211 | /* IP is not in table. No associated cleanups. */ | |
212 | /* ??? This is where C++ calls std::terminate to catch throw | |
213 | from a destructor. */ | |
617a1b71 | 214 | CONTINUE_UNWINDING; |
0bfa5f65 RH |
215 | |
216 | found_something: | |
217 | if (landing_pad == 0) | |
218 | { | |
219 | /* IP is present, but has a null landing pad. | |
220 | No handler to be run. */ | |
617a1b71 | 221 | CONTINUE_UNWINDING; |
0bfa5f65 RH |
222 | } |
223 | ||
224 | _Unwind_SetGR (context, __builtin_eh_return_data_regno (0), | |
225 | (_Unwind_Ptr) ue_header); | |
226 | _Unwind_SetGR (context, __builtin_eh_return_data_regno (1), 0); | |
227 | _Unwind_SetIP (context, landing_pad); | |
228 | return _URC_INSTALL_CONTEXT; | |
229 | } |