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8fdef16c | 1 | /* DWARF2 exception handling CFA execution engine. |
83ffe9cd | 2 | Copyright (C) 1997-2023 Free Software Foundation, Inc. |
8fdef16c FW |
3 | |
4 | This file is part of GCC. | |
5 | ||
6 | GCC is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 3, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GCC is distributed in the hope that it will be useful, but WITHOUT | |
12 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
13 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public | |
14 | License for more details. | |
15 | ||
16 | Under Section 7 of GPL version 3, you are granted additional | |
17 | permissions described in the GCC Runtime Library Exception, version | |
18 | 3.1, as published by the Free Software Foundation. | |
19 | ||
20 | You should have received a copy of the GNU General Public License and | |
21 | a copy of the GCC Runtime Library Exception along with this program; | |
22 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | <http://www.gnu.org/licenses/>. */ | |
24 | ||
25 | /* This file is included from unwind-dw2.c to specialize the code for certain | |
26 | values of DATA_ALIGN and CODE_ALIGN. These macros must be defined prior to | |
27 | including this file. */ | |
28 | ||
29 | { | |
30 | struct frame_state_reg_info *unused_rs = NULL; | |
31 | ||
32 | /* Don't allow remember/restore between CIE and FDE programs. */ | |
33 | fs->regs.prev = NULL; | |
34 | ||
35 | /* The comparison with the return address uses < rather than <= because | |
36 | we are only interested in the effects of code before the call; for a | |
37 | noreturn function, the return address may point to unrelated code with | |
38 | a different stack configuration that we are not interested in. We | |
39 | assume that the call itself is unwind info-neutral; if not, or if | |
40 | there are delay instructions that adjust the stack, these must be | |
41 | reflected at the point immediately before the call insn. | |
42 | In signal frames, return address is after last completed instruction, | |
43 | so we add 1 to return address to make the comparison <=. */ | |
44 | while (insn_ptr < insn_end | |
45 | && fs->pc < context->ra + _Unwind_IsSignalFrame (context)) | |
46 | { | |
47 | unsigned char insn = *insn_ptr++; | |
48 | _uleb128_t reg, utmp; | |
49 | _sleb128_t offset, stmp; | |
50 | ||
51 | if ((insn & 0xc0) == DW_CFA_advance_loc) | |
52 | fs->pc += (insn & 0x3f) * CODE_ALIGN; | |
53 | else if ((insn & 0xc0) == DW_CFA_offset) | |
54 | { | |
55 | reg = insn & 0x3f; | |
56 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
57 | offset = (_Unwind_Sword) utmp * DATA_ALIGN; | |
58 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
59 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
60 | { | |
61 | fs->regs.how[reg] = REG_SAVED_OFFSET; | |
62 | fs->regs.reg[reg].loc.offset = offset; | |
63 | } | |
64 | } | |
65 | else if ((insn & 0xc0) == DW_CFA_restore) | |
66 | { | |
67 | reg = insn & 0x3f; | |
68 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
69 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
70 | fs->regs.how[reg] = REG_UNSAVED; | |
71 | } | |
72 | else switch (insn) | |
73 | { | |
74 | case DW_CFA_set_loc: | |
75 | { | |
76 | _Unwind_Ptr pc; | |
77 | ||
78 | insn_ptr = read_encoded_value (context, fs->fde_encoding, | |
79 | insn_ptr, &pc); | |
80 | fs->pc = (void *) pc; | |
81 | } | |
82 | break; | |
83 | ||
84 | case DW_CFA_advance_loc1: | |
85 | fs->pc += read_1u (insn_ptr) * CODE_ALIGN; | |
86 | insn_ptr += 1; | |
87 | break; | |
88 | case DW_CFA_advance_loc2: | |
89 | fs->pc += read_2u (insn_ptr) * CODE_ALIGN; | |
90 | insn_ptr += 2; | |
91 | break; | |
92 | case DW_CFA_advance_loc4: | |
93 | fs->pc += read_4u (insn_ptr) * CODE_ALIGN; | |
94 | insn_ptr += 4; | |
95 | break; | |
96 | ||
97 | case DW_CFA_offset_extended: | |
98 | insn_ptr = read_uleb128 (insn_ptr, ®); | |
99 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
100 | offset = (_Unwind_Sword) utmp * DATA_ALIGN; | |
101 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
102 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
103 | { | |
104 | fs->regs.how[reg] = REG_SAVED_OFFSET; | |
105 | fs->regs.reg[reg].loc.offset = offset; | |
106 | } | |
107 | break; | |
108 | ||
109 | case DW_CFA_restore_extended: | |
110 | insn_ptr = read_uleb128 (insn_ptr, ®); | |
111 | /* FIXME, this is wrong; the CIE might have said that the | |
112 | register was saved somewhere. */ | |
113 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
114 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
115 | fs->regs.how[reg] = REG_UNSAVED; | |
116 | break; | |
117 | ||
118 | case DW_CFA_same_value: | |
119 | insn_ptr = read_uleb128 (insn_ptr, ®); | |
120 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
121 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
122 | fs->regs.how[reg] = REG_UNSAVED; | |
123 | break; | |
124 | ||
125 | case DW_CFA_undefined: | |
126 | insn_ptr = read_uleb128 (insn_ptr, ®); | |
127 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
128 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
129 | fs->regs.how[reg] = REG_UNDEFINED; | |
130 | break; | |
131 | ||
132 | case DW_CFA_nop: | |
133 | break; | |
134 | ||
135 | case DW_CFA_register: | |
136 | { | |
137 | _uleb128_t reg2; | |
138 | insn_ptr = read_uleb128 (insn_ptr, ®); | |
139 | insn_ptr = read_uleb128 (insn_ptr, ®2); | |
140 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
141 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
142 | { | |
143 | fs->regs.how[reg] = REG_SAVED_REG; | |
144 | fs->regs.reg[reg].loc.reg = (_Unwind_Word)reg2; | |
145 | } | |
146 | } | |
147 | break; | |
148 | ||
149 | case DW_CFA_remember_state: | |
150 | { | |
151 | struct frame_state_reg_info *new_rs; | |
152 | if (unused_rs) | |
153 | { | |
154 | new_rs = unused_rs; | |
155 | unused_rs = unused_rs->prev; | |
156 | } | |
157 | else | |
158 | new_rs = alloca (sizeof (struct frame_state_reg_info)); | |
159 | ||
160 | *new_rs = fs->regs; | |
161 | fs->regs.prev = new_rs; | |
162 | } | |
163 | break; | |
164 | ||
165 | case DW_CFA_restore_state: | |
166 | { | |
167 | struct frame_state_reg_info *old_rs = fs->regs.prev; | |
168 | fs->regs = *old_rs; | |
169 | old_rs->prev = unused_rs; | |
170 | unused_rs = old_rs; | |
171 | } | |
172 | break; | |
173 | ||
174 | case DW_CFA_def_cfa: | |
175 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
176 | fs->regs.cfa_reg = (_Unwind_Word)utmp; | |
177 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
178 | fs->regs.cfa_offset = (_Unwind_Word)utmp; | |
179 | fs->regs.cfa_how = CFA_REG_OFFSET; | |
180 | break; | |
181 | ||
182 | case DW_CFA_def_cfa_register: | |
183 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
184 | fs->regs.cfa_reg = (_Unwind_Word)utmp; | |
185 | fs->regs.cfa_how = CFA_REG_OFFSET; | |
186 | break; | |
187 | ||
188 | case DW_CFA_def_cfa_offset: | |
189 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
190 | fs->regs.cfa_offset = utmp; | |
191 | /* cfa_how deliberately not set. */ | |
192 | break; | |
193 | ||
194 | case DW_CFA_def_cfa_expression: | |
195 | fs->regs.cfa_exp = insn_ptr; | |
196 | fs->regs.cfa_how = CFA_EXP; | |
197 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
198 | insn_ptr += utmp; | |
199 | break; | |
200 | ||
201 | case DW_CFA_expression: | |
202 | insn_ptr = read_uleb128 (insn_ptr, ®); | |
203 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
204 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
205 | { | |
206 | fs->regs.how[reg] = REG_SAVED_EXP; | |
207 | fs->regs.reg[reg].loc.exp = insn_ptr; | |
208 | } | |
209 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
210 | insn_ptr += utmp; | |
211 | break; | |
212 | ||
213 | /* Dwarf3. */ | |
214 | case DW_CFA_offset_extended_sf: | |
215 | insn_ptr = read_uleb128 (insn_ptr, ®); | |
216 | insn_ptr = read_sleb128 (insn_ptr, &stmp); | |
217 | offset = stmp * DATA_ALIGN; | |
218 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
219 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
220 | { | |
221 | fs->regs.how[reg] = REG_SAVED_OFFSET; | |
222 | fs->regs.reg[reg].loc.offset = offset; | |
223 | } | |
224 | break; | |
225 | ||
226 | case DW_CFA_def_cfa_sf: | |
227 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
228 | fs->regs.cfa_reg = (_Unwind_Word)utmp; | |
229 | insn_ptr = read_sleb128 (insn_ptr, &stmp); | |
230 | fs->regs.cfa_offset = (_Unwind_Sword)stmp; | |
231 | fs->regs.cfa_how = CFA_REG_OFFSET; | |
232 | fs->regs.cfa_offset *= DATA_ALIGN; | |
233 | break; | |
234 | ||
235 | case DW_CFA_def_cfa_offset_sf: | |
236 | insn_ptr = read_sleb128 (insn_ptr, &stmp); | |
237 | fs->regs.cfa_offset = (_Unwind_Sword)stmp; | |
238 | fs->regs.cfa_offset *= DATA_ALIGN; | |
239 | /* cfa_how deliberately not set. */ | |
240 | break; | |
241 | ||
242 | case DW_CFA_val_offset: | |
243 | insn_ptr = read_uleb128 (insn_ptr, ®); | |
244 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
245 | offset = (_Unwind_Sword) utmp * DATA_ALIGN; | |
246 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
247 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
248 | { | |
249 | fs->regs.how[reg] = REG_SAVED_VAL_OFFSET; | |
250 | fs->regs.reg[reg].loc.offset = offset; | |
251 | } | |
252 | break; | |
253 | ||
254 | case DW_CFA_val_offset_sf: | |
255 | insn_ptr = read_uleb128 (insn_ptr, ®); | |
256 | insn_ptr = read_sleb128 (insn_ptr, &stmp); | |
257 | offset = stmp * DATA_ALIGN; | |
258 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
259 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
260 | { | |
261 | fs->regs.how[reg] = REG_SAVED_VAL_OFFSET; | |
262 | fs->regs.reg[reg].loc.offset = offset; | |
263 | } | |
264 | break; | |
265 | ||
266 | case DW_CFA_val_expression: | |
267 | insn_ptr = read_uleb128 (insn_ptr, ®); | |
268 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
269 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
270 | { | |
271 | fs->regs.how[reg] = REG_SAVED_VAL_EXP; | |
272 | fs->regs.reg[reg].loc.exp = insn_ptr; | |
273 | } | |
274 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
275 | insn_ptr += utmp; | |
276 | break; | |
277 | ||
278 | case DW_CFA_GNU_window_save: | |
279 | #if defined (__aarch64__) && !defined (__ILP32__) | |
280 | /* This CFA is multiplexed with Sparc. On AArch64 it's used to toggle | |
c98cd1df WD |
281 | return address signing status. REG_UNSAVED/REG_UNSAVED_ARCHEXT |
282 | mean RA signing is disabled/enabled. */ | |
8fdef16c | 283 | reg = DWARF_REGNUM_AARCH64_RA_STATE; |
c98cd1df WD |
284 | gcc_assert (fs->regs.how[reg] == REG_UNSAVED |
285 | || fs->regs.how[reg] == REG_UNSAVED_ARCHEXT); | |
286 | if (fs->regs.how[reg] == REG_UNSAVED) | |
287 | fs->regs.how[reg] = REG_UNSAVED_ARCHEXT; | |
288 | else | |
289 | fs->regs.how[reg] = REG_UNSAVED; | |
8fdef16c FW |
290 | #else |
291 | /* ??? Hardcoded for SPARC register window configuration. */ | |
292 | if (__LIBGCC_DWARF_FRAME_REGISTERS__ >= 32) | |
293 | for (reg = 16; reg < 32; ++reg) | |
294 | { | |
295 | fs->regs.how[reg] = REG_SAVED_OFFSET; | |
296 | fs->regs.reg[reg].loc.offset = (reg - 16) * sizeof (void *); | |
297 | } | |
298 | #endif | |
299 | break; | |
300 | ||
301 | case DW_CFA_GNU_args_size: | |
302 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
303 | context->args_size = (_Unwind_Word)utmp; | |
304 | break; | |
305 | ||
306 | case DW_CFA_GNU_negative_offset_extended: | |
307 | /* Obsoleted by DW_CFA_offset_extended_sf, but used by | |
308 | older PowerPC code. */ | |
309 | insn_ptr = read_uleb128 (insn_ptr, ®); | |
310 | insn_ptr = read_uleb128 (insn_ptr, &utmp); | |
311 | offset = (_Unwind_Word) utmp * DATA_ALIGN; | |
312 | reg = DWARF_REG_TO_UNWIND_COLUMN (reg); | |
313 | if (UNWIND_COLUMN_IN_RANGE (reg)) | |
314 | { | |
315 | fs->regs.how[reg] = REG_SAVED_OFFSET; | |
316 | fs->regs.reg[reg].loc.offset = -offset; | |
317 | } | |
318 | break; | |
319 | ||
320 | default: | |
321 | gcc_unreachable (); | |
322 | } | |
323 | } | |
324 | } | |
325 | ||
326 | #undef DATA_ALIGN | |
327 | #undef CODE_ALIGN |