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Commit | Line | Data |
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cfc14b3a MK |
1 | /* Frame unwinder for frames with DWARF Call Frame Information. |
2 | ||
197e01b6 | 3 | Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc. |
cfc14b3a MK |
4 | |
5 | Contributed by Mark Kettenis. | |
6 | ||
7 | This file is part of GDB. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 2 of the License, or | |
12 | (at your option) any later version. | |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with this program; if not, write to the Free Software | |
197e01b6 EZ |
21 | Foundation, Inc., 51 Franklin Street, Fifth Floor, |
22 | Boston, MA 02110-1301, USA. */ | |
cfc14b3a MK |
23 | |
24 | #include "defs.h" | |
25 | #include "dwarf2expr.h" | |
26 | #include "elf/dwarf2.h" | |
27 | #include "frame.h" | |
28 | #include "frame-base.h" | |
29 | #include "frame-unwind.h" | |
30 | #include "gdbcore.h" | |
31 | #include "gdbtypes.h" | |
32 | #include "symtab.h" | |
33 | #include "objfiles.h" | |
34 | #include "regcache.h" | |
f2da6b3a | 35 | #include "value.h" |
cfc14b3a MK |
36 | |
37 | #include "gdb_assert.h" | |
38 | #include "gdb_string.h" | |
39 | ||
6896c0c7 | 40 | #include "complaints.h" |
cfc14b3a MK |
41 | #include "dwarf2-frame.h" |
42 | ||
43 | /* Call Frame Information (CFI). */ | |
44 | ||
45 | /* Common Information Entry (CIE). */ | |
46 | ||
47 | struct dwarf2_cie | |
48 | { | |
49 | /* Offset into the .debug_frame section where this CIE was found. | |
50 | Used to identify this CIE. */ | |
51 | ULONGEST cie_pointer; | |
52 | ||
53 | /* Constant that is factored out of all advance location | |
54 | instructions. */ | |
55 | ULONGEST code_alignment_factor; | |
56 | ||
57 | /* Constants that is factored out of all offset instructions. */ | |
58 | LONGEST data_alignment_factor; | |
59 | ||
60 | /* Return address column. */ | |
61 | ULONGEST return_address_register; | |
62 | ||
63 | /* Instruction sequence to initialize a register set. */ | |
852483bc MK |
64 | gdb_byte *initial_instructions; |
65 | gdb_byte *end; | |
cfc14b3a MK |
66 | |
67 | /* Encoding of addresses. */ | |
852483bc | 68 | gdb_byte encoding; |
cfc14b3a | 69 | |
7131cb6e RH |
70 | /* True if a 'z' augmentation existed. */ |
71 | unsigned char saw_z_augmentation; | |
72 | ||
56c987f6 AO |
73 | /* True if an 'S' augmentation existed. */ |
74 | unsigned char signal_frame; | |
75 | ||
cfc14b3a MK |
76 | struct dwarf2_cie *next; |
77 | }; | |
78 | ||
79 | /* Frame Description Entry (FDE). */ | |
80 | ||
81 | struct dwarf2_fde | |
82 | { | |
83 | /* CIE for this FDE. */ | |
84 | struct dwarf2_cie *cie; | |
85 | ||
86 | /* First location associated with this FDE. */ | |
87 | CORE_ADDR initial_location; | |
88 | ||
89 | /* Number of bytes of program instructions described by this FDE. */ | |
90 | CORE_ADDR address_range; | |
91 | ||
92 | /* Instruction sequence. */ | |
852483bc MK |
93 | gdb_byte *instructions; |
94 | gdb_byte *end; | |
cfc14b3a | 95 | |
4bf8967c AS |
96 | /* True if this FDE is read from a .eh_frame instead of a .debug_frame |
97 | section. */ | |
98 | unsigned char eh_frame_p; | |
99 | ||
cfc14b3a MK |
100 | struct dwarf2_fde *next; |
101 | }; | |
102 | ||
103 | static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc); | |
104 | \f | |
105 | ||
106 | /* Structure describing a frame state. */ | |
107 | ||
108 | struct dwarf2_frame_state | |
109 | { | |
110 | /* Each register save state can be described in terms of a CFA slot, | |
111 | another register, or a location expression. */ | |
112 | struct dwarf2_frame_state_reg_info | |
113 | { | |
05cbe71a | 114 | struct dwarf2_frame_state_reg *reg; |
cfc14b3a MK |
115 | int num_regs; |
116 | ||
117 | /* Used to implement DW_CFA_remember_state. */ | |
118 | struct dwarf2_frame_state_reg_info *prev; | |
119 | } regs; | |
120 | ||
121 | LONGEST cfa_offset; | |
122 | ULONGEST cfa_reg; | |
852483bc | 123 | gdb_byte *cfa_exp; |
cfc14b3a MK |
124 | enum { |
125 | CFA_UNSET, | |
126 | CFA_REG_OFFSET, | |
127 | CFA_EXP | |
128 | } cfa_how; | |
129 | ||
130 | /* The PC described by the current frame state. */ | |
131 | CORE_ADDR pc; | |
132 | ||
133 | /* Initial register set from the CIE. | |
134 | Used to implement DW_CFA_restore. */ | |
135 | struct dwarf2_frame_state_reg_info initial; | |
136 | ||
137 | /* The information we care about from the CIE. */ | |
138 | LONGEST data_align; | |
139 | ULONGEST code_align; | |
140 | ULONGEST retaddr_column; | |
141 | }; | |
142 | ||
143 | /* Store the length the expression for the CFA in the `cfa_reg' field, | |
144 | which is unused in that case. */ | |
145 | #define cfa_exp_len cfa_reg | |
146 | ||
147 | /* Assert that the register set RS is large enough to store NUM_REGS | |
148 | columns. If necessary, enlarge the register set. */ | |
149 | ||
150 | static void | |
151 | dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs, | |
152 | int num_regs) | |
153 | { | |
154 | size_t size = sizeof (struct dwarf2_frame_state_reg); | |
155 | ||
156 | if (num_regs <= rs->num_regs) | |
157 | return; | |
158 | ||
159 | rs->reg = (struct dwarf2_frame_state_reg *) | |
160 | xrealloc (rs->reg, num_regs * size); | |
161 | ||
162 | /* Initialize newly allocated registers. */ | |
2473a4a9 | 163 | memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size); |
cfc14b3a MK |
164 | rs->num_regs = num_regs; |
165 | } | |
166 | ||
167 | /* Copy the register columns in register set RS into newly allocated | |
168 | memory and return a pointer to this newly created copy. */ | |
169 | ||
170 | static struct dwarf2_frame_state_reg * | |
171 | dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs) | |
172 | { | |
d10891d4 | 173 | size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg); |
cfc14b3a MK |
174 | struct dwarf2_frame_state_reg *reg; |
175 | ||
176 | reg = (struct dwarf2_frame_state_reg *) xmalloc (size); | |
177 | memcpy (reg, rs->reg, size); | |
178 | ||
179 | return reg; | |
180 | } | |
181 | ||
182 | /* Release the memory allocated to register set RS. */ | |
183 | ||
184 | static void | |
185 | dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs) | |
186 | { | |
187 | if (rs) | |
188 | { | |
189 | dwarf2_frame_state_free_regs (rs->prev); | |
190 | ||
191 | xfree (rs->reg); | |
192 | xfree (rs); | |
193 | } | |
194 | } | |
195 | ||
196 | /* Release the memory allocated to the frame state FS. */ | |
197 | ||
198 | static void | |
199 | dwarf2_frame_state_free (void *p) | |
200 | { | |
201 | struct dwarf2_frame_state *fs = p; | |
202 | ||
203 | dwarf2_frame_state_free_regs (fs->initial.prev); | |
204 | dwarf2_frame_state_free_regs (fs->regs.prev); | |
205 | xfree (fs->initial.reg); | |
206 | xfree (fs->regs.reg); | |
207 | xfree (fs); | |
208 | } | |
209 | \f | |
210 | ||
211 | /* Helper functions for execute_stack_op. */ | |
212 | ||
213 | static CORE_ADDR | |
214 | read_reg (void *baton, int reg) | |
215 | { | |
216 | struct frame_info *next_frame = (struct frame_info *) baton; | |
05cbe71a | 217 | struct gdbarch *gdbarch = get_frame_arch (next_frame); |
cfc14b3a | 218 | int regnum; |
852483bc | 219 | gdb_byte *buf; |
cfc14b3a MK |
220 | |
221 | regnum = DWARF2_REG_TO_REGNUM (reg); | |
222 | ||
852483bc | 223 | buf = alloca (register_size (gdbarch, regnum)); |
cfc14b3a | 224 | frame_unwind_register (next_frame, regnum, buf); |
f2da6b3a DJ |
225 | |
226 | /* Convert the register to an integer. This returns a LONGEST | |
227 | rather than a CORE_ADDR, but unpack_pointer does the same thing | |
228 | under the covers, and this makes more sense for non-pointer | |
229 | registers. Maybe read_reg and the associated interfaces should | |
230 | deal with "struct value" instead of CORE_ADDR. */ | |
231 | return unpack_long (register_type (gdbarch, regnum), buf); | |
cfc14b3a MK |
232 | } |
233 | ||
234 | static void | |
852483bc | 235 | read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
cfc14b3a MK |
236 | { |
237 | read_memory (addr, buf, len); | |
238 | } | |
239 | ||
240 | static void | |
852483bc | 241 | no_get_frame_base (void *baton, gdb_byte **start, size_t *length) |
cfc14b3a MK |
242 | { |
243 | internal_error (__FILE__, __LINE__, | |
e2e0b3e5 | 244 | _("Support for DW_OP_fbreg is unimplemented")); |
cfc14b3a MK |
245 | } |
246 | ||
247 | static CORE_ADDR | |
248 | no_get_tls_address (void *baton, CORE_ADDR offset) | |
249 | { | |
250 | internal_error (__FILE__, __LINE__, | |
e2e0b3e5 | 251 | _("Support for DW_OP_GNU_push_tls_address is unimplemented")); |
cfc14b3a MK |
252 | } |
253 | ||
254 | static CORE_ADDR | |
852483bc | 255 | execute_stack_op (gdb_byte *exp, ULONGEST len, |
cfc14b3a MK |
256 | struct frame_info *next_frame, CORE_ADDR initial) |
257 | { | |
258 | struct dwarf_expr_context *ctx; | |
259 | CORE_ADDR result; | |
260 | ||
261 | ctx = new_dwarf_expr_context (); | |
262 | ctx->baton = next_frame; | |
263 | ctx->read_reg = read_reg; | |
264 | ctx->read_mem = read_mem; | |
265 | ctx->get_frame_base = no_get_frame_base; | |
266 | ctx->get_tls_address = no_get_tls_address; | |
267 | ||
268 | dwarf_expr_push (ctx, initial); | |
269 | dwarf_expr_eval (ctx, exp, len); | |
270 | result = dwarf_expr_fetch (ctx, 0); | |
271 | ||
272 | if (ctx->in_reg) | |
273 | result = read_reg (next_frame, result); | |
274 | ||
275 | free_dwarf_expr_context (ctx); | |
276 | ||
277 | return result; | |
278 | } | |
279 | \f | |
280 | ||
281 | static void | |
852483bc | 282 | execute_cfa_program (gdb_byte *insn_ptr, gdb_byte *insn_end, |
cfc14b3a | 283 | struct frame_info *next_frame, |
4bf8967c | 284 | struct dwarf2_frame_state *fs, int eh_frame_p) |
cfc14b3a MK |
285 | { |
286 | CORE_ADDR pc = frame_pc_unwind (next_frame); | |
287 | int bytes_read; | |
4bf8967c | 288 | struct gdbarch *gdbarch = get_frame_arch (next_frame); |
cfc14b3a MK |
289 | |
290 | while (insn_ptr < insn_end && fs->pc <= pc) | |
291 | { | |
852483bc | 292 | gdb_byte insn = *insn_ptr++; |
cfc14b3a MK |
293 | ULONGEST utmp, reg; |
294 | LONGEST offset; | |
295 | ||
296 | if ((insn & 0xc0) == DW_CFA_advance_loc) | |
297 | fs->pc += (insn & 0x3f) * fs->code_align; | |
298 | else if ((insn & 0xc0) == DW_CFA_offset) | |
299 | { | |
300 | reg = insn & 0x3f; | |
4bf8967c AS |
301 | if (eh_frame_p) |
302 | reg = dwarf2_frame_eh_frame_regnum (gdbarch, reg); | |
cfc14b3a MK |
303 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
304 | offset = utmp * fs->data_align; | |
305 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
05cbe71a | 306 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
cfc14b3a MK |
307 | fs->regs.reg[reg].loc.offset = offset; |
308 | } | |
309 | else if ((insn & 0xc0) == DW_CFA_restore) | |
310 | { | |
311 | gdb_assert (fs->initial.reg); | |
312 | reg = insn & 0x3f; | |
4bf8967c AS |
313 | if (eh_frame_p) |
314 | reg = dwarf2_frame_eh_frame_regnum (gdbarch, reg); | |
cfc14b3a | 315 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
92ad9f6b FR |
316 | if (reg < fs->initial.num_regs) |
317 | fs->regs.reg[reg] = fs->initial.reg[reg]; | |
318 | else | |
319 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED; | |
320 | ||
321 | if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED) | |
322 | complaint (&symfile_complaints, _("\ | |
323 | incomplete CFI data; DW_CFA_restore unspecified\n\ | |
324 | register %s (#%d) at 0x%s"), | |
325 | REGISTER_NAME(DWARF2_REG_TO_REGNUM(reg)), | |
326 | DWARF2_REG_TO_REGNUM(reg), paddr (fs->pc)); | |
cfc14b3a MK |
327 | } |
328 | else | |
329 | { | |
330 | switch (insn) | |
331 | { | |
332 | case DW_CFA_set_loc: | |
333 | fs->pc = dwarf2_read_address (insn_ptr, insn_end, &bytes_read); | |
334 | insn_ptr += bytes_read; | |
335 | break; | |
336 | ||
337 | case DW_CFA_advance_loc1: | |
338 | utmp = extract_unsigned_integer (insn_ptr, 1); | |
339 | fs->pc += utmp * fs->code_align; | |
340 | insn_ptr++; | |
341 | break; | |
342 | case DW_CFA_advance_loc2: | |
343 | utmp = extract_unsigned_integer (insn_ptr, 2); | |
344 | fs->pc += utmp * fs->code_align; | |
345 | insn_ptr += 2; | |
346 | break; | |
347 | case DW_CFA_advance_loc4: | |
348 | utmp = extract_unsigned_integer (insn_ptr, 4); | |
349 | fs->pc += utmp * fs->code_align; | |
350 | insn_ptr += 4; | |
351 | break; | |
352 | ||
353 | case DW_CFA_offset_extended: | |
354 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
4bf8967c AS |
355 | if (eh_frame_p) |
356 | reg = dwarf2_frame_eh_frame_regnum (gdbarch, reg); | |
cfc14b3a MK |
357 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
358 | offset = utmp * fs->data_align; | |
359 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
05cbe71a | 360 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
cfc14b3a MK |
361 | fs->regs.reg[reg].loc.offset = offset; |
362 | break; | |
363 | ||
364 | case DW_CFA_restore_extended: | |
365 | gdb_assert (fs->initial.reg); | |
366 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
4bf8967c AS |
367 | if (eh_frame_p) |
368 | reg = dwarf2_frame_eh_frame_regnum (gdbarch, reg); | |
cfc14b3a MK |
369 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
370 | fs->regs.reg[reg] = fs->initial.reg[reg]; | |
371 | break; | |
372 | ||
373 | case DW_CFA_undefined: | |
374 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
4bf8967c AS |
375 | if (eh_frame_p) |
376 | reg = dwarf2_frame_eh_frame_regnum (gdbarch, reg); | |
cfc14b3a | 377 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
05cbe71a | 378 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED; |
cfc14b3a MK |
379 | break; |
380 | ||
381 | case DW_CFA_same_value: | |
382 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
4bf8967c AS |
383 | if (eh_frame_p) |
384 | reg = dwarf2_frame_eh_frame_regnum (gdbarch, reg); | |
cfc14b3a | 385 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
05cbe71a | 386 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE; |
cfc14b3a MK |
387 | break; |
388 | ||
389 | case DW_CFA_register: | |
390 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
4bf8967c AS |
391 | if (eh_frame_p) |
392 | reg = dwarf2_frame_eh_frame_regnum (gdbarch, reg); | |
cfc14b3a | 393 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
4bf8967c AS |
394 | if (eh_frame_p) |
395 | utmp = dwarf2_frame_eh_frame_regnum (gdbarch, utmp); | |
cfc14b3a | 396 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
05cbe71a | 397 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG; |
cfc14b3a MK |
398 | fs->regs.reg[reg].loc.reg = utmp; |
399 | break; | |
400 | ||
401 | case DW_CFA_remember_state: | |
402 | { | |
403 | struct dwarf2_frame_state_reg_info *new_rs; | |
404 | ||
405 | new_rs = XMALLOC (struct dwarf2_frame_state_reg_info); | |
406 | *new_rs = fs->regs; | |
407 | fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs); | |
408 | fs->regs.prev = new_rs; | |
409 | } | |
410 | break; | |
411 | ||
412 | case DW_CFA_restore_state: | |
413 | { | |
414 | struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev; | |
415 | ||
50ea7769 MK |
416 | if (old_rs == NULL) |
417 | { | |
e2e0b3e5 AC |
418 | complaint (&symfile_complaints, _("\ |
419 | bad CFI data; mismatched DW_CFA_restore_state at 0x%s"), paddr (fs->pc)); | |
50ea7769 MK |
420 | } |
421 | else | |
422 | { | |
423 | xfree (fs->regs.reg); | |
424 | fs->regs = *old_rs; | |
425 | xfree (old_rs); | |
426 | } | |
cfc14b3a MK |
427 | } |
428 | break; | |
429 | ||
430 | case DW_CFA_def_cfa: | |
431 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); | |
432 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
433 | fs->cfa_offset = utmp; | |
434 | fs->cfa_how = CFA_REG_OFFSET; | |
435 | break; | |
436 | ||
437 | case DW_CFA_def_cfa_register: | |
438 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); | |
4bf8967c AS |
439 | if (eh_frame_p) |
440 | fs->cfa_reg = dwarf2_frame_eh_frame_regnum (gdbarch, | |
441 | fs->cfa_reg); | |
cfc14b3a MK |
442 | fs->cfa_how = CFA_REG_OFFSET; |
443 | break; | |
444 | ||
445 | case DW_CFA_def_cfa_offset: | |
852483bc MK |
446 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
447 | fs->cfa_offset = utmp; | |
cfc14b3a MK |
448 | /* cfa_how deliberately not set. */ |
449 | break; | |
450 | ||
a8504492 MK |
451 | case DW_CFA_nop: |
452 | break; | |
453 | ||
cfc14b3a MK |
454 | case DW_CFA_def_cfa_expression: |
455 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_exp_len); | |
456 | fs->cfa_exp = insn_ptr; | |
457 | fs->cfa_how = CFA_EXP; | |
458 | insn_ptr += fs->cfa_exp_len; | |
459 | break; | |
460 | ||
461 | case DW_CFA_expression: | |
462 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
4bf8967c AS |
463 | if (eh_frame_p) |
464 | reg = dwarf2_frame_eh_frame_regnum (gdbarch, reg); | |
cfc14b3a MK |
465 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
466 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
467 | fs->regs.reg[reg].loc.exp = insn_ptr; | |
468 | fs->regs.reg[reg].exp_len = utmp; | |
05cbe71a | 469 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP; |
cfc14b3a MK |
470 | insn_ptr += utmp; |
471 | break; | |
472 | ||
a8504492 MK |
473 | case DW_CFA_offset_extended_sf: |
474 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
4bf8967c AS |
475 | if (eh_frame_p) |
476 | reg = dwarf2_frame_eh_frame_regnum (gdbarch, reg); | |
a8504492 | 477 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); |
f6da8dd8 | 478 | offset *= fs->data_align; |
a8504492 | 479 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
05cbe71a | 480 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
a8504492 MK |
481 | fs->regs.reg[reg].loc.offset = offset; |
482 | break; | |
483 | ||
484 | case DW_CFA_def_cfa_sf: | |
485 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); | |
4bf8967c AS |
486 | if (eh_frame_p) |
487 | fs->cfa_reg = dwarf2_frame_eh_frame_regnum (gdbarch, | |
488 | fs->cfa_reg); | |
a8504492 MK |
489 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); |
490 | fs->cfa_offset = offset * fs->data_align; | |
491 | fs->cfa_how = CFA_REG_OFFSET; | |
492 | break; | |
493 | ||
494 | case DW_CFA_def_cfa_offset_sf: | |
495 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); | |
496 | fs->cfa_offset = offset * fs->data_align; | |
497 | /* cfa_how deliberately not set. */ | |
cfc14b3a MK |
498 | break; |
499 | ||
a77f4086 MK |
500 | case DW_CFA_GNU_window_save: |
501 | /* This is SPARC-specific code, and contains hard-coded | |
502 | constants for the register numbering scheme used by | |
503 | GCC. Rather than having a architecture-specific | |
504 | operation that's only ever used by a single | |
505 | architecture, we provide the implementation here. | |
506 | Incidentally that's what GCC does too in its | |
507 | unwinder. */ | |
508 | { | |
509 | struct gdbarch *gdbarch = get_frame_arch (next_frame); | |
510 | int size = register_size(gdbarch, 0); | |
511 | dwarf2_frame_state_alloc_regs (&fs->regs, 32); | |
512 | for (reg = 8; reg < 16; reg++) | |
513 | { | |
514 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG; | |
515 | fs->regs.reg[reg].loc.reg = reg + 16; | |
516 | } | |
517 | for (reg = 16; reg < 32; reg++) | |
518 | { | |
519 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; | |
520 | fs->regs.reg[reg].loc.offset = (reg - 16) * size; | |
521 | } | |
522 | } | |
523 | break; | |
524 | ||
cfc14b3a MK |
525 | case DW_CFA_GNU_args_size: |
526 | /* Ignored. */ | |
527 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
528 | break; | |
529 | ||
530 | default: | |
e2e0b3e5 | 531 | internal_error (__FILE__, __LINE__, _("Unknown CFI encountered.")); |
cfc14b3a MK |
532 | } |
533 | } | |
534 | } | |
535 | ||
536 | /* Don't allow remember/restore between CIE and FDE programs. */ | |
537 | dwarf2_frame_state_free_regs (fs->regs.prev); | |
538 | fs->regs.prev = NULL; | |
539 | } | |
8f22cb90 | 540 | \f |
cfc14b3a | 541 | |
8f22cb90 | 542 | /* Architecture-specific operations. */ |
cfc14b3a | 543 | |
8f22cb90 MK |
544 | /* Per-architecture data key. */ |
545 | static struct gdbarch_data *dwarf2_frame_data; | |
546 | ||
547 | struct dwarf2_frame_ops | |
548 | { | |
549 | /* Pre-initialize the register state REG for register REGNUM. */ | |
aff37fc1 DM |
550 | void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *, |
551 | struct frame_info *); | |
3ed09a32 DJ |
552 | |
553 | /* Check whether the frame preceding NEXT_FRAME will be a signal | |
554 | trampoline. */ | |
555 | int (*signal_frame_p) (struct gdbarch *, struct frame_info *); | |
4bf8967c AS |
556 | |
557 | /* Convert .eh_frame register number to DWARF register number. */ | |
558 | int (*eh_frame_regnum) (struct gdbarch *, int); | |
cfc14b3a MK |
559 | }; |
560 | ||
8f22cb90 MK |
561 | /* Default architecture-specific register state initialization |
562 | function. */ | |
563 | ||
564 | static void | |
565 | dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum, | |
aff37fc1 DM |
566 | struct dwarf2_frame_state_reg *reg, |
567 | struct frame_info *next_frame) | |
8f22cb90 MK |
568 | { |
569 | /* If we have a register that acts as a program counter, mark it as | |
570 | a destination for the return address. If we have a register that | |
571 | serves as the stack pointer, arrange for it to be filled with the | |
572 | call frame address (CFA). The other registers are marked as | |
573 | unspecified. | |
574 | ||
575 | We copy the return address to the program counter, since many | |
576 | parts in GDB assume that it is possible to get the return address | |
577 | by unwinding the program counter register. However, on ISA's | |
578 | with a dedicated return address register, the CFI usually only | |
579 | contains information to unwind that return address register. | |
580 | ||
581 | The reason we're treating the stack pointer special here is | |
582 | because in many cases GCC doesn't emit CFI for the stack pointer | |
583 | and implicitly assumes that it is equal to the CFA. This makes | |
584 | some sense since the DWARF specification (version 3, draft 8, | |
585 | p. 102) says that: | |
586 | ||
587 | "Typically, the CFA is defined to be the value of the stack | |
588 | pointer at the call site in the previous frame (which may be | |
589 | different from its value on entry to the current frame)." | |
590 | ||
591 | However, this isn't true for all platforms supported by GCC | |
592 | (e.g. IBM S/390 and zSeries). Those architectures should provide | |
593 | their own architecture-specific initialization function. */ | |
05cbe71a | 594 | |
8f22cb90 MK |
595 | if (regnum == PC_REGNUM) |
596 | reg->how = DWARF2_FRAME_REG_RA; | |
597 | else if (regnum == SP_REGNUM) | |
598 | reg->how = DWARF2_FRAME_REG_CFA; | |
599 | } | |
05cbe71a | 600 | |
8f22cb90 | 601 | /* Return a default for the architecture-specific operations. */ |
05cbe71a | 602 | |
8f22cb90 | 603 | static void * |
030f20e1 | 604 | dwarf2_frame_init (struct obstack *obstack) |
8f22cb90 MK |
605 | { |
606 | struct dwarf2_frame_ops *ops; | |
607 | ||
030f20e1 | 608 | ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops); |
8f22cb90 MK |
609 | ops->init_reg = dwarf2_frame_default_init_reg; |
610 | return ops; | |
611 | } | |
05cbe71a | 612 | |
8f22cb90 MK |
613 | /* Set the architecture-specific register state initialization |
614 | function for GDBARCH to INIT_REG. */ | |
615 | ||
616 | void | |
617 | dwarf2_frame_set_init_reg (struct gdbarch *gdbarch, | |
618 | void (*init_reg) (struct gdbarch *, int, | |
aff37fc1 DM |
619 | struct dwarf2_frame_state_reg *, |
620 | struct frame_info *)) | |
8f22cb90 | 621 | { |
030f20e1 | 622 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
8f22cb90 | 623 | |
8f22cb90 MK |
624 | ops->init_reg = init_reg; |
625 | } | |
626 | ||
627 | /* Pre-initialize the register state REG for register REGNUM. */ | |
05cbe71a MK |
628 | |
629 | static void | |
630 | dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum, | |
aff37fc1 DM |
631 | struct dwarf2_frame_state_reg *reg, |
632 | struct frame_info *next_frame) | |
05cbe71a | 633 | { |
030f20e1 | 634 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
8f22cb90 | 635 | |
aff37fc1 | 636 | ops->init_reg (gdbarch, regnum, reg, next_frame); |
05cbe71a | 637 | } |
3ed09a32 DJ |
638 | |
639 | /* Set the architecture-specific signal trampoline recognition | |
640 | function for GDBARCH to SIGNAL_FRAME_P. */ | |
641 | ||
642 | void | |
643 | dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch, | |
644 | int (*signal_frame_p) (struct gdbarch *, | |
645 | struct frame_info *)) | |
646 | { | |
647 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); | |
648 | ||
649 | ops->signal_frame_p = signal_frame_p; | |
650 | } | |
651 | ||
652 | /* Query the architecture-specific signal frame recognizer for | |
653 | NEXT_FRAME. */ | |
654 | ||
655 | static int | |
656 | dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch, | |
657 | struct frame_info *next_frame) | |
658 | { | |
659 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); | |
660 | ||
661 | if (ops->signal_frame_p == NULL) | |
662 | return 0; | |
663 | return ops->signal_frame_p (gdbarch, next_frame); | |
664 | } | |
4bf8967c AS |
665 | |
666 | /* Set the architecture-specific mapping of .eh_frame register numbers to | |
667 | DWARF register numbers. */ | |
668 | ||
669 | void | |
670 | dwarf2_frame_set_eh_frame_regnum (struct gdbarch *gdbarch, | |
671 | int (*eh_frame_regnum) (struct gdbarch *, | |
672 | int)) | |
673 | { | |
674 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); | |
675 | ||
676 | ops->eh_frame_regnum = eh_frame_regnum; | |
677 | } | |
678 | ||
679 | /* Translate a .eh_frame register to DWARF register. */ | |
680 | ||
681 | int | |
682 | dwarf2_frame_eh_frame_regnum (struct gdbarch *gdbarch, int regnum) | |
683 | { | |
684 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); | |
685 | ||
686 | if (ops->eh_frame_regnum == NULL) | |
687 | return regnum; | |
688 | return ops->eh_frame_regnum (gdbarch, regnum); | |
689 | } | |
8f22cb90 MK |
690 | \f |
691 | ||
692 | struct dwarf2_frame_cache | |
693 | { | |
694 | /* DWARF Call Frame Address. */ | |
695 | CORE_ADDR cfa; | |
696 | ||
0228dfb9 DJ |
697 | /* Set if the return address column was marked as undefined. */ |
698 | int undefined_retaddr; | |
699 | ||
8f22cb90 MK |
700 | /* Saved registers, indexed by GDB register number, not by DWARF |
701 | register number. */ | |
702 | struct dwarf2_frame_state_reg *reg; | |
8d5a9abc MK |
703 | |
704 | /* Return address register. */ | |
705 | struct dwarf2_frame_state_reg retaddr_reg; | |
8f22cb90 | 706 | }; |
05cbe71a | 707 | |
b9362cc7 | 708 | static struct dwarf2_frame_cache * |
cfc14b3a MK |
709 | dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache) |
710 | { | |
711 | struct cleanup *old_chain; | |
05cbe71a | 712 | struct gdbarch *gdbarch = get_frame_arch (next_frame); |
3e2c4033 | 713 | const int num_regs = NUM_REGS + NUM_PSEUDO_REGS; |
cfc14b3a MK |
714 | struct dwarf2_frame_cache *cache; |
715 | struct dwarf2_frame_state *fs; | |
716 | struct dwarf2_fde *fde; | |
cfc14b3a MK |
717 | |
718 | if (*this_cache) | |
719 | return *this_cache; | |
720 | ||
721 | /* Allocate a new cache. */ | |
722 | cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache); | |
723 | cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg); | |
724 | ||
725 | /* Allocate and initialize the frame state. */ | |
726 | fs = XMALLOC (struct dwarf2_frame_state); | |
727 | memset (fs, 0, sizeof (struct dwarf2_frame_state)); | |
728 | old_chain = make_cleanup (dwarf2_frame_state_free, fs); | |
729 | ||
730 | /* Unwind the PC. | |
731 | ||
732 | Note that if NEXT_FRAME is never supposed to return (i.e. a call | |
733 | to abort), the compiler might optimize away the instruction at | |
734 | NEXT_FRAME's return address. As a result the return address will | |
735 | point at some random instruction, and the CFI for that | |
e4e9607c | 736 | instruction is probably worthless to us. GCC's unwinder solves |
cfc14b3a MK |
737 | this problem by substracting 1 from the return address to get an |
738 | address in the middle of a presumed call instruction (or the | |
739 | instruction in the associated delay slot). This should only be | |
740 | done for "normal" frames and not for resume-type frames (signal | |
e4e9607c MK |
741 | handlers, sentinel frames, dummy frames). The function |
742 | frame_unwind_address_in_block does just this. It's not clear how | |
743 | reliable the method is though; there is the potential for the | |
744 | register state pre-call being different to that on return. */ | |
1ce5d6dd | 745 | fs->pc = frame_unwind_address_in_block (next_frame); |
cfc14b3a MK |
746 | |
747 | /* Find the correct FDE. */ | |
748 | fde = dwarf2_frame_find_fde (&fs->pc); | |
749 | gdb_assert (fde != NULL); | |
750 | ||
751 | /* Extract any interesting information from the CIE. */ | |
752 | fs->data_align = fde->cie->data_alignment_factor; | |
753 | fs->code_align = fde->cie->code_alignment_factor; | |
754 | fs->retaddr_column = fde->cie->return_address_register; | |
755 | ||
756 | /* First decode all the insns in the CIE. */ | |
757 | execute_cfa_program (fde->cie->initial_instructions, | |
4bf8967c | 758 | fde->cie->end, next_frame, fs, fde->eh_frame_p); |
cfc14b3a MK |
759 | |
760 | /* Save the initialized register set. */ | |
761 | fs->initial = fs->regs; | |
762 | fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs); | |
763 | ||
764 | /* Then decode the insns in the FDE up to our target PC. */ | |
4bf8967c AS |
765 | execute_cfa_program (fde->instructions, fde->end, next_frame, fs, |
766 | fde->eh_frame_p); | |
cfc14b3a MK |
767 | |
768 | /* Caclulate the CFA. */ | |
769 | switch (fs->cfa_how) | |
770 | { | |
771 | case CFA_REG_OFFSET: | |
772 | cache->cfa = read_reg (next_frame, fs->cfa_reg); | |
773 | cache->cfa += fs->cfa_offset; | |
774 | break; | |
775 | ||
776 | case CFA_EXP: | |
777 | cache->cfa = | |
778 | execute_stack_op (fs->cfa_exp, fs->cfa_exp_len, next_frame, 0); | |
779 | break; | |
780 | ||
781 | default: | |
e2e0b3e5 | 782 | internal_error (__FILE__, __LINE__, _("Unknown CFA rule.")); |
cfc14b3a MK |
783 | } |
784 | ||
05cbe71a | 785 | /* Initialize the register state. */ |
3e2c4033 AC |
786 | { |
787 | int regnum; | |
e4e9607c | 788 | |
3e2c4033 | 789 | for (regnum = 0; regnum < num_regs; regnum++) |
aff37fc1 | 790 | dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], next_frame); |
3e2c4033 AC |
791 | } |
792 | ||
793 | /* Go through the DWARF2 CFI generated table and save its register | |
79c4cb80 MK |
794 | location information in the cache. Note that we don't skip the |
795 | return address column; it's perfectly all right for it to | |
796 | correspond to a real register. If it doesn't correspond to a | |
797 | real register, or if we shouldn't treat it as such, | |
798 | DWARF2_REG_TO_REGNUM should be defined to return a number outside | |
799 | the range [0, NUM_REGS). */ | |
3e2c4033 AC |
800 | { |
801 | int column; /* CFI speak for "register number". */ | |
e4e9607c | 802 | |
3e2c4033 AC |
803 | for (column = 0; column < fs->regs.num_regs; column++) |
804 | { | |
3e2c4033 | 805 | /* Use the GDB register number as the destination index. */ |
79c4cb80 | 806 | int regnum = DWARF2_REG_TO_REGNUM (column); |
3e2c4033 AC |
807 | |
808 | /* If there's no corresponding GDB register, ignore it. */ | |
809 | if (regnum < 0 || regnum >= num_regs) | |
810 | continue; | |
811 | ||
812 | /* NOTE: cagney/2003-09-05: CFI should specify the disposition | |
e4e9607c MK |
813 | of all debug info registers. If it doesn't, complain (but |
814 | not too loudly). It turns out that GCC assumes that an | |
3e2c4033 AC |
815 | unspecified register implies "same value" when CFI (draft |
816 | 7) specifies nothing at all. Such a register could equally | |
817 | be interpreted as "undefined". Also note that this check | |
e4e9607c MK |
818 | isn't sufficient; it only checks that all registers in the |
819 | range [0 .. max column] are specified, and won't detect | |
3e2c4033 | 820 | problems when a debug info register falls outside of the |
e4e9607c | 821 | table. We need a way of iterating through all the valid |
3e2c4033 | 822 | DWARF2 register numbers. */ |
05cbe71a | 823 | if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED) |
f059bf6f AC |
824 | { |
825 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED) | |
e2e0b3e5 AC |
826 | complaint (&symfile_complaints, _("\ |
827 | incomplete CFI data; unspecified registers (e.g., %s) at 0x%s"), | |
f059bf6f AC |
828 | gdbarch_register_name (gdbarch, regnum), |
829 | paddr_nz (fs->pc)); | |
830 | } | |
35889917 MK |
831 | else |
832 | cache->reg[regnum] = fs->regs.reg[column]; | |
3e2c4033 AC |
833 | } |
834 | } | |
cfc14b3a | 835 | |
8d5a9abc MK |
836 | /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information |
837 | we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */ | |
35889917 MK |
838 | { |
839 | int regnum; | |
840 | ||
841 | for (regnum = 0; regnum < num_regs; regnum++) | |
842 | { | |
8d5a9abc MK |
843 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA |
844 | || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET) | |
35889917 | 845 | { |
05cbe71a MK |
846 | struct dwarf2_frame_state_reg *retaddr_reg = |
847 | &fs->regs.reg[fs->retaddr_column]; | |
848 | ||
d4f10bf2 MK |
849 | /* It seems rather bizarre to specify an "empty" column as |
850 | the return adress column. However, this is exactly | |
851 | what GCC does on some targets. It turns out that GCC | |
852 | assumes that the return address can be found in the | |
853 | register corresponding to the return address column. | |
8d5a9abc MK |
854 | Incidentally, that's how we should treat a return |
855 | address column specifying "same value" too. */ | |
d4f10bf2 | 856 | if (fs->retaddr_column < fs->regs.num_regs |
05cbe71a MK |
857 | && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED |
858 | && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE) | |
8d5a9abc MK |
859 | { |
860 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA) | |
861 | cache->reg[regnum] = *retaddr_reg; | |
862 | else | |
863 | cache->retaddr_reg = *retaddr_reg; | |
864 | } | |
35889917 MK |
865 | else |
866 | { | |
8d5a9abc MK |
867 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA) |
868 | { | |
869 | cache->reg[regnum].loc.reg = fs->retaddr_column; | |
870 | cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG; | |
871 | } | |
872 | else | |
873 | { | |
874 | cache->retaddr_reg.loc.reg = fs->retaddr_column; | |
875 | cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG; | |
876 | } | |
35889917 MK |
877 | } |
878 | } | |
879 | } | |
880 | } | |
cfc14b3a | 881 | |
0228dfb9 DJ |
882 | if (fs->retaddr_column < fs->regs.num_regs |
883 | && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED) | |
884 | cache->undefined_retaddr = 1; | |
885 | ||
cfc14b3a MK |
886 | do_cleanups (old_chain); |
887 | ||
888 | *this_cache = cache; | |
889 | return cache; | |
890 | } | |
891 | ||
892 | static void | |
893 | dwarf2_frame_this_id (struct frame_info *next_frame, void **this_cache, | |
894 | struct frame_id *this_id) | |
895 | { | |
896 | struct dwarf2_frame_cache *cache = | |
897 | dwarf2_frame_cache (next_frame, this_cache); | |
898 | ||
0228dfb9 DJ |
899 | if (cache->undefined_retaddr) |
900 | return; | |
901 | ||
cfc14b3a MK |
902 | (*this_id) = frame_id_build (cache->cfa, frame_func_unwind (next_frame)); |
903 | } | |
904 | ||
905 | static void | |
906 | dwarf2_frame_prev_register (struct frame_info *next_frame, void **this_cache, | |
907 | int regnum, int *optimizedp, | |
908 | enum lval_type *lvalp, CORE_ADDR *addrp, | |
c6826062 | 909 | int *realnump, gdb_byte *valuep) |
cfc14b3a | 910 | { |
05cbe71a | 911 | struct gdbarch *gdbarch = get_frame_arch (next_frame); |
cfc14b3a MK |
912 | struct dwarf2_frame_cache *cache = |
913 | dwarf2_frame_cache (next_frame, this_cache); | |
914 | ||
915 | switch (cache->reg[regnum].how) | |
916 | { | |
05cbe71a | 917 | case DWARF2_FRAME_REG_UNDEFINED: |
3e2c4033 | 918 | /* If CFI explicitly specified that the value isn't defined, |
e4e9607c | 919 | mark it as optimized away; the value isn't available. */ |
cfc14b3a MK |
920 | *optimizedp = 1; |
921 | *lvalp = not_lval; | |
922 | *addrp = 0; | |
923 | *realnump = -1; | |
35889917 | 924 | if (valuep) |
cfc14b3a MK |
925 | { |
926 | /* In some cases, for example %eflags on the i386, we have | |
927 | to provide a sane value, even though this register wasn't | |
928 | saved. Assume we can get it from NEXT_FRAME. */ | |
929 | frame_unwind_register (next_frame, regnum, valuep); | |
930 | } | |
931 | break; | |
932 | ||
05cbe71a | 933 | case DWARF2_FRAME_REG_SAVED_OFFSET: |
cfc14b3a MK |
934 | *optimizedp = 0; |
935 | *lvalp = lval_memory; | |
936 | *addrp = cache->cfa + cache->reg[regnum].loc.offset; | |
937 | *realnump = -1; | |
938 | if (valuep) | |
939 | { | |
940 | /* Read the value in from memory. */ | |
05cbe71a | 941 | read_memory (*addrp, valuep, register_size (gdbarch, regnum)); |
cfc14b3a MK |
942 | } |
943 | break; | |
944 | ||
05cbe71a | 945 | case DWARF2_FRAME_REG_SAVED_REG: |
00b25ff3 AC |
946 | *optimizedp = 0; |
947 | *lvalp = lval_register; | |
948 | *addrp = 0; | |
949 | *realnump = DWARF2_REG_TO_REGNUM (cache->reg[regnum].loc.reg); | |
950 | if (valuep) | |
951 | frame_unwind_register (next_frame, (*realnump), valuep); | |
cfc14b3a MK |
952 | break; |
953 | ||
05cbe71a | 954 | case DWARF2_FRAME_REG_SAVED_EXP: |
cfc14b3a MK |
955 | *optimizedp = 0; |
956 | *lvalp = lval_memory; | |
957 | *addrp = execute_stack_op (cache->reg[regnum].loc.exp, | |
958 | cache->reg[regnum].exp_len, | |
959 | next_frame, cache->cfa); | |
960 | *realnump = -1; | |
961 | if (valuep) | |
962 | { | |
963 | /* Read the value in from memory. */ | |
05cbe71a | 964 | read_memory (*addrp, valuep, register_size (gdbarch, regnum)); |
cfc14b3a MK |
965 | } |
966 | break; | |
967 | ||
05cbe71a | 968 | case DWARF2_FRAME_REG_UNSPECIFIED: |
3e2c4033 AC |
969 | /* GCC, in its infinite wisdom decided to not provide unwind |
970 | information for registers that are "same value". Since | |
971 | DWARF2 (3 draft 7) doesn't define such behavior, said | |
972 | registers are actually undefined (which is different to CFI | |
973 | "undefined"). Code above issues a complaint about this. | |
974 | Here just fudge the books, assume GCC, and that the value is | |
975 | more inner on the stack. */ | |
00b25ff3 AC |
976 | *optimizedp = 0; |
977 | *lvalp = lval_register; | |
978 | *addrp = 0; | |
979 | *realnump = regnum; | |
980 | if (valuep) | |
981 | frame_unwind_register (next_frame, (*realnump), valuep); | |
3e2c4033 AC |
982 | break; |
983 | ||
05cbe71a | 984 | case DWARF2_FRAME_REG_SAME_VALUE: |
00b25ff3 AC |
985 | *optimizedp = 0; |
986 | *lvalp = lval_register; | |
987 | *addrp = 0; | |
988 | *realnump = regnum; | |
989 | if (valuep) | |
990 | frame_unwind_register (next_frame, (*realnump), valuep); | |
cfc14b3a MK |
991 | break; |
992 | ||
05cbe71a | 993 | case DWARF2_FRAME_REG_CFA: |
35889917 MK |
994 | *optimizedp = 0; |
995 | *lvalp = not_lval; | |
996 | *addrp = 0; | |
997 | *realnump = -1; | |
998 | if (valuep) | |
999 | { | |
1000 | /* Store the value. */ | |
1001 | store_typed_address (valuep, builtin_type_void_data_ptr, cache->cfa); | |
1002 | } | |
1003 | break; | |
1004 | ||
ea7963f0 FR |
1005 | case DWARF2_FRAME_REG_CFA_OFFSET: |
1006 | *optimizedp = 0; | |
1007 | *lvalp = not_lval; | |
1008 | *addrp = 0; | |
1009 | *realnump = -1; | |
1010 | if (valuep) | |
1011 | { | |
1012 | /* Store the value. */ | |
1013 | store_typed_address (valuep, builtin_type_void_data_ptr, | |
1014 | cache->cfa + cache->reg[regnum].loc.offset); | |
1015 | } | |
1016 | break; | |
1017 | ||
8d5a9abc MK |
1018 | case DWARF2_FRAME_REG_RA_OFFSET: |
1019 | *optimizedp = 0; | |
1020 | *lvalp = not_lval; | |
1021 | *addrp = 0; | |
1022 | *realnump = -1; | |
1023 | if (valuep) | |
1024 | { | |
1025 | CORE_ADDR pc = cache->reg[regnum].loc.offset; | |
1026 | ||
1027 | regnum = DWARF2_REG_TO_REGNUM (cache->retaddr_reg.loc.reg); | |
1028 | pc += frame_unwind_register_unsigned (next_frame, regnum); | |
1029 | store_typed_address (valuep, builtin_type_void_func_ptr, pc); | |
1030 | } | |
1031 | break; | |
1032 | ||
cfc14b3a | 1033 | default: |
e2e0b3e5 | 1034 | internal_error (__FILE__, __LINE__, _("Unknown register rule.")); |
cfc14b3a MK |
1035 | } |
1036 | } | |
1037 | ||
1038 | static const struct frame_unwind dwarf2_frame_unwind = | |
1039 | { | |
1040 | NORMAL_FRAME, | |
1041 | dwarf2_frame_this_id, | |
1042 | dwarf2_frame_prev_register | |
1043 | }; | |
1044 | ||
3ed09a32 DJ |
1045 | static const struct frame_unwind dwarf2_signal_frame_unwind = |
1046 | { | |
1047 | SIGTRAMP_FRAME, | |
1048 | dwarf2_frame_this_id, | |
1049 | dwarf2_frame_prev_register | |
1050 | }; | |
1051 | ||
cfc14b3a | 1052 | const struct frame_unwind * |
336d1bba | 1053 | dwarf2_frame_sniffer (struct frame_info *next_frame) |
cfc14b3a | 1054 | { |
1ce5d6dd AC |
1055 | /* Grab an address that is guarenteed to reside somewhere within the |
1056 | function. frame_pc_unwind(), for a no-return next function, can | |
1057 | end up returning something past the end of this function's body. */ | |
1058 | CORE_ADDR block_addr = frame_unwind_address_in_block (next_frame); | |
56c987f6 AO |
1059 | struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr); |
1060 | if (!fde) | |
3ed09a32 DJ |
1061 | return NULL; |
1062 | ||
1063 | /* On some targets, signal trampolines may have unwind information. | |
1064 | We need to recognize them so that we set the frame type | |
1065 | correctly. */ | |
1066 | ||
56c987f6 AO |
1067 | if (fde->cie->signal_frame |
1068 | || dwarf2_frame_signal_frame_p (get_frame_arch (next_frame), | |
1069 | next_frame)) | |
3ed09a32 | 1070 | return &dwarf2_signal_frame_unwind; |
cfc14b3a | 1071 | |
3ed09a32 | 1072 | return &dwarf2_frame_unwind; |
cfc14b3a MK |
1073 | } |
1074 | \f | |
1075 | ||
1076 | /* There is no explicitly defined relationship between the CFA and the | |
1077 | location of frame's local variables and arguments/parameters. | |
1078 | Therefore, frame base methods on this page should probably only be | |
1079 | used as a last resort, just to avoid printing total garbage as a | |
1080 | response to the "info frame" command. */ | |
1081 | ||
1082 | static CORE_ADDR | |
1083 | dwarf2_frame_base_address (struct frame_info *next_frame, void **this_cache) | |
1084 | { | |
1085 | struct dwarf2_frame_cache *cache = | |
1086 | dwarf2_frame_cache (next_frame, this_cache); | |
1087 | ||
1088 | return cache->cfa; | |
1089 | } | |
1090 | ||
1091 | static const struct frame_base dwarf2_frame_base = | |
1092 | { | |
1093 | &dwarf2_frame_unwind, | |
1094 | dwarf2_frame_base_address, | |
1095 | dwarf2_frame_base_address, | |
1096 | dwarf2_frame_base_address | |
1097 | }; | |
1098 | ||
1099 | const struct frame_base * | |
336d1bba | 1100 | dwarf2_frame_base_sniffer (struct frame_info *next_frame) |
cfc14b3a | 1101 | { |
336d1bba | 1102 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
cfc14b3a MK |
1103 | if (dwarf2_frame_find_fde (&pc)) |
1104 | return &dwarf2_frame_base; | |
1105 | ||
1106 | return NULL; | |
1107 | } | |
1108 | \f | |
1109 | /* A minimal decoding of DWARF2 compilation units. We only decode | |
1110 | what's needed to get to the call frame information. */ | |
1111 | ||
1112 | struct comp_unit | |
1113 | { | |
1114 | /* Keep the bfd convenient. */ | |
1115 | bfd *abfd; | |
1116 | ||
1117 | struct objfile *objfile; | |
1118 | ||
1119 | /* Linked list of CIEs for this object. */ | |
1120 | struct dwarf2_cie *cie; | |
1121 | ||
cfc14b3a | 1122 | /* Pointer to the .debug_frame section loaded into memory. */ |
852483bc | 1123 | gdb_byte *dwarf_frame_buffer; |
cfc14b3a MK |
1124 | |
1125 | /* Length of the loaded .debug_frame section. */ | |
1126 | unsigned long dwarf_frame_size; | |
1127 | ||
1128 | /* Pointer to the .debug_frame section. */ | |
1129 | asection *dwarf_frame_section; | |
0912c7f2 MK |
1130 | |
1131 | /* Base for DW_EH_PE_datarel encodings. */ | |
1132 | bfd_vma dbase; | |
0fd85043 CV |
1133 | |
1134 | /* Base for DW_EH_PE_textrel encodings. */ | |
1135 | bfd_vma tbase; | |
cfc14b3a MK |
1136 | }; |
1137 | ||
8f22cb90 | 1138 | const struct objfile_data *dwarf2_frame_objfile_data; |
0d0e1a63 | 1139 | |
cfc14b3a | 1140 | static unsigned int |
852483bc | 1141 | read_1_byte (bfd *abfd, gdb_byte *buf) |
cfc14b3a | 1142 | { |
852483bc | 1143 | return bfd_get_8 (abfd, buf); |
cfc14b3a MK |
1144 | } |
1145 | ||
1146 | static unsigned int | |
852483bc | 1147 | read_4_bytes (bfd *abfd, gdb_byte *buf) |
cfc14b3a | 1148 | { |
852483bc | 1149 | return bfd_get_32 (abfd, buf); |
cfc14b3a MK |
1150 | } |
1151 | ||
1152 | static ULONGEST | |
852483bc | 1153 | read_8_bytes (bfd *abfd, gdb_byte *buf) |
cfc14b3a | 1154 | { |
852483bc | 1155 | return bfd_get_64 (abfd, buf); |
cfc14b3a MK |
1156 | } |
1157 | ||
1158 | static ULONGEST | |
852483bc | 1159 | read_unsigned_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr) |
cfc14b3a MK |
1160 | { |
1161 | ULONGEST result; | |
1162 | unsigned int num_read; | |
1163 | int shift; | |
852483bc | 1164 | gdb_byte byte; |
cfc14b3a MK |
1165 | |
1166 | result = 0; | |
1167 | shift = 0; | |
1168 | num_read = 0; | |
1169 | ||
1170 | do | |
1171 | { | |
1172 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); | |
1173 | buf++; | |
1174 | num_read++; | |
1175 | result |= ((byte & 0x7f) << shift); | |
1176 | shift += 7; | |
1177 | } | |
1178 | while (byte & 0x80); | |
1179 | ||
1180 | *bytes_read_ptr = num_read; | |
1181 | ||
1182 | return result; | |
1183 | } | |
1184 | ||
1185 | static LONGEST | |
852483bc | 1186 | read_signed_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr) |
cfc14b3a MK |
1187 | { |
1188 | LONGEST result; | |
1189 | int shift; | |
1190 | unsigned int num_read; | |
852483bc | 1191 | gdb_byte byte; |
cfc14b3a MK |
1192 | |
1193 | result = 0; | |
1194 | shift = 0; | |
1195 | num_read = 0; | |
1196 | ||
1197 | do | |
1198 | { | |
1199 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); | |
1200 | buf++; | |
1201 | num_read++; | |
1202 | result |= ((byte & 0x7f) << shift); | |
1203 | shift += 7; | |
1204 | } | |
1205 | while (byte & 0x80); | |
1206 | ||
77e0b926 DJ |
1207 | if (shift < 8 * sizeof (result) && (byte & 0x40)) |
1208 | result |= -(((LONGEST)1) << shift); | |
cfc14b3a MK |
1209 | |
1210 | *bytes_read_ptr = num_read; | |
1211 | ||
1212 | return result; | |
1213 | } | |
1214 | ||
1215 | static ULONGEST | |
852483bc | 1216 | read_initial_length (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr) |
cfc14b3a MK |
1217 | { |
1218 | LONGEST result; | |
1219 | ||
852483bc | 1220 | result = bfd_get_32 (abfd, buf); |
cfc14b3a MK |
1221 | if (result == 0xffffffff) |
1222 | { | |
852483bc | 1223 | result = bfd_get_64 (abfd, buf + 4); |
cfc14b3a MK |
1224 | *bytes_read_ptr = 12; |
1225 | } | |
1226 | else | |
1227 | *bytes_read_ptr = 4; | |
1228 | ||
1229 | return result; | |
1230 | } | |
1231 | \f | |
1232 | ||
1233 | /* Pointer encoding helper functions. */ | |
1234 | ||
1235 | /* GCC supports exception handling based on DWARF2 CFI. However, for | |
1236 | technical reasons, it encodes addresses in its FDE's in a different | |
1237 | way. Several "pointer encodings" are supported. The encoding | |
1238 | that's used for a particular FDE is determined by the 'R' | |
1239 | augmentation in the associated CIE. The argument of this | |
1240 | augmentation is a single byte. | |
1241 | ||
1242 | The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a | |
1243 | LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether | |
1244 | the address is signed or unsigned. Bits 4, 5 and 6 encode how the | |
1245 | address should be interpreted (absolute, relative to the current | |
1246 | position in the FDE, ...). Bit 7, indicates that the address | |
1247 | should be dereferenced. */ | |
1248 | ||
852483bc | 1249 | static gdb_byte |
cfc14b3a MK |
1250 | encoding_for_size (unsigned int size) |
1251 | { | |
1252 | switch (size) | |
1253 | { | |
1254 | case 2: | |
1255 | return DW_EH_PE_udata2; | |
1256 | case 4: | |
1257 | return DW_EH_PE_udata4; | |
1258 | case 8: | |
1259 | return DW_EH_PE_udata8; | |
1260 | default: | |
e2e0b3e5 | 1261 | internal_error (__FILE__, __LINE__, _("Unsupported address size")); |
cfc14b3a MK |
1262 | } |
1263 | } | |
1264 | ||
1265 | static unsigned int | |
852483bc | 1266 | size_of_encoded_value (gdb_byte encoding) |
cfc14b3a MK |
1267 | { |
1268 | if (encoding == DW_EH_PE_omit) | |
1269 | return 0; | |
1270 | ||
1271 | switch (encoding & 0x07) | |
1272 | { | |
1273 | case DW_EH_PE_absptr: | |
1274 | return TYPE_LENGTH (builtin_type_void_data_ptr); | |
1275 | case DW_EH_PE_udata2: | |
1276 | return 2; | |
1277 | case DW_EH_PE_udata4: | |
1278 | return 4; | |
1279 | case DW_EH_PE_udata8: | |
1280 | return 8; | |
1281 | default: | |
e2e0b3e5 | 1282 | internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding")); |
cfc14b3a MK |
1283 | } |
1284 | } | |
1285 | ||
1286 | static CORE_ADDR | |
852483bc MK |
1287 | read_encoded_value (struct comp_unit *unit, gdb_byte encoding, |
1288 | gdb_byte *buf, unsigned int *bytes_read_ptr) | |
cfc14b3a | 1289 | { |
68f6cf99 MK |
1290 | int ptr_len = size_of_encoded_value (DW_EH_PE_absptr); |
1291 | ptrdiff_t offset; | |
cfc14b3a MK |
1292 | CORE_ADDR base; |
1293 | ||
1294 | /* GCC currently doesn't generate DW_EH_PE_indirect encodings for | |
1295 | FDE's. */ | |
1296 | if (encoding & DW_EH_PE_indirect) | |
1297 | internal_error (__FILE__, __LINE__, | |
e2e0b3e5 | 1298 | _("Unsupported encoding: DW_EH_PE_indirect")); |
cfc14b3a | 1299 | |
68f6cf99 MK |
1300 | *bytes_read_ptr = 0; |
1301 | ||
cfc14b3a MK |
1302 | switch (encoding & 0x70) |
1303 | { | |
1304 | case DW_EH_PE_absptr: | |
1305 | base = 0; | |
1306 | break; | |
1307 | case DW_EH_PE_pcrel: | |
1308 | base = bfd_get_section_vma (unit->bfd, unit->dwarf_frame_section); | |
852483bc | 1309 | base += (buf - unit->dwarf_frame_buffer); |
cfc14b3a | 1310 | break; |
0912c7f2 MK |
1311 | case DW_EH_PE_datarel: |
1312 | base = unit->dbase; | |
1313 | break; | |
0fd85043 CV |
1314 | case DW_EH_PE_textrel: |
1315 | base = unit->tbase; | |
1316 | break; | |
03ac2a74 MK |
1317 | case DW_EH_PE_funcrel: |
1318 | /* FIXME: kettenis/20040501: For now just pretend | |
1319 | DW_EH_PE_funcrel is equivalent to DW_EH_PE_absptr. For | |
1320 | reading the initial location of an FDE it should be treated | |
1321 | as such, and currently that's the only place where this code | |
1322 | is used. */ | |
1323 | base = 0; | |
1324 | break; | |
68f6cf99 MK |
1325 | case DW_EH_PE_aligned: |
1326 | base = 0; | |
852483bc | 1327 | offset = buf - unit->dwarf_frame_buffer; |
68f6cf99 MK |
1328 | if ((offset % ptr_len) != 0) |
1329 | { | |
1330 | *bytes_read_ptr = ptr_len - (offset % ptr_len); | |
1331 | buf += *bytes_read_ptr; | |
1332 | } | |
1333 | break; | |
cfc14b3a | 1334 | default: |
e2e0b3e5 | 1335 | internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding")); |
cfc14b3a MK |
1336 | } |
1337 | ||
b04de778 | 1338 | if ((encoding & 0x07) == 0x00) |
68f6cf99 | 1339 | encoding |= encoding_for_size (ptr_len); |
cfc14b3a MK |
1340 | |
1341 | switch (encoding & 0x0f) | |
1342 | { | |
a81b10ae MK |
1343 | case DW_EH_PE_uleb128: |
1344 | { | |
1345 | ULONGEST value; | |
852483bc | 1346 | gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7; |
a7289609 | 1347 | *bytes_read_ptr += read_uleb128 (buf, end_buf, &value) - buf; |
a81b10ae MK |
1348 | return base + value; |
1349 | } | |
cfc14b3a | 1350 | case DW_EH_PE_udata2: |
68f6cf99 | 1351 | *bytes_read_ptr += 2; |
cfc14b3a MK |
1352 | return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf)); |
1353 | case DW_EH_PE_udata4: | |
68f6cf99 | 1354 | *bytes_read_ptr += 4; |
cfc14b3a MK |
1355 | return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf)); |
1356 | case DW_EH_PE_udata8: | |
68f6cf99 | 1357 | *bytes_read_ptr += 8; |
cfc14b3a | 1358 | return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf)); |
a81b10ae MK |
1359 | case DW_EH_PE_sleb128: |
1360 | { | |
1361 | LONGEST value; | |
852483bc | 1362 | gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7; |
a7289609 | 1363 | *bytes_read_ptr += read_sleb128 (buf, end_buf, &value) - buf; |
a81b10ae MK |
1364 | return base + value; |
1365 | } | |
cfc14b3a | 1366 | case DW_EH_PE_sdata2: |
68f6cf99 | 1367 | *bytes_read_ptr += 2; |
cfc14b3a MK |
1368 | return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf)); |
1369 | case DW_EH_PE_sdata4: | |
68f6cf99 | 1370 | *bytes_read_ptr += 4; |
cfc14b3a MK |
1371 | return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf)); |
1372 | case DW_EH_PE_sdata8: | |
68f6cf99 | 1373 | *bytes_read_ptr += 8; |
cfc14b3a MK |
1374 | return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf)); |
1375 | default: | |
e2e0b3e5 | 1376 | internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding")); |
cfc14b3a MK |
1377 | } |
1378 | } | |
1379 | \f | |
1380 | ||
1381 | /* GCC uses a single CIE for all FDEs in a .debug_frame section. | |
1382 | That's why we use a simple linked list here. */ | |
1383 | ||
1384 | static struct dwarf2_cie * | |
1385 | find_cie (struct comp_unit *unit, ULONGEST cie_pointer) | |
1386 | { | |
1387 | struct dwarf2_cie *cie = unit->cie; | |
1388 | ||
1389 | while (cie) | |
1390 | { | |
1391 | if (cie->cie_pointer == cie_pointer) | |
1392 | return cie; | |
1393 | ||
1394 | cie = cie->next; | |
1395 | } | |
1396 | ||
1397 | return NULL; | |
1398 | } | |
1399 | ||
1400 | static void | |
1401 | add_cie (struct comp_unit *unit, struct dwarf2_cie *cie) | |
1402 | { | |
1403 | cie->next = unit->cie; | |
1404 | unit->cie = cie; | |
1405 | } | |
1406 | ||
1407 | /* Find the FDE for *PC. Return a pointer to the FDE, and store the | |
1408 | inital location associated with it into *PC. */ | |
1409 | ||
1410 | static struct dwarf2_fde * | |
1411 | dwarf2_frame_find_fde (CORE_ADDR *pc) | |
1412 | { | |
1413 | struct objfile *objfile; | |
1414 | ||
1415 | ALL_OBJFILES (objfile) | |
1416 | { | |
1417 | struct dwarf2_fde *fde; | |
1418 | CORE_ADDR offset; | |
1419 | ||
8f22cb90 | 1420 | fde = objfile_data (objfile, dwarf2_frame_objfile_data); |
4ae9ee8e DJ |
1421 | if (fde == NULL) |
1422 | continue; | |
1423 | ||
1424 | gdb_assert (objfile->section_offsets); | |
1425 | offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile)); | |
1426 | ||
cfc14b3a MK |
1427 | while (fde) |
1428 | { | |
1429 | if (*pc >= fde->initial_location + offset | |
1430 | && *pc < fde->initial_location + offset + fde->address_range) | |
1431 | { | |
1432 | *pc = fde->initial_location + offset; | |
1433 | return fde; | |
1434 | } | |
1435 | ||
1436 | fde = fde->next; | |
1437 | } | |
1438 | } | |
1439 | ||
1440 | return NULL; | |
1441 | } | |
1442 | ||
1443 | static void | |
1444 | add_fde (struct comp_unit *unit, struct dwarf2_fde *fde) | |
1445 | { | |
8f22cb90 MK |
1446 | fde->next = objfile_data (unit->objfile, dwarf2_frame_objfile_data); |
1447 | set_objfile_data (unit->objfile, dwarf2_frame_objfile_data, fde); | |
cfc14b3a MK |
1448 | } |
1449 | ||
1450 | #ifdef CC_HAS_LONG_LONG | |
1451 | #define DW64_CIE_ID 0xffffffffffffffffULL | |
1452 | #else | |
1453 | #define DW64_CIE_ID ~0 | |
1454 | #endif | |
1455 | ||
852483bc MK |
1456 | static gdb_byte *decode_frame_entry (struct comp_unit *unit, gdb_byte *start, |
1457 | int eh_frame_p); | |
cfc14b3a | 1458 | |
6896c0c7 RH |
1459 | /* Decode the next CIE or FDE. Return NULL if invalid input, otherwise |
1460 | the next byte to be processed. */ | |
852483bc MK |
1461 | static gdb_byte * |
1462 | decode_frame_entry_1 (struct comp_unit *unit, gdb_byte *start, int eh_frame_p) | |
cfc14b3a | 1463 | { |
852483bc | 1464 | gdb_byte *buf, *end; |
cfc14b3a MK |
1465 | LONGEST length; |
1466 | unsigned int bytes_read; | |
6896c0c7 RH |
1467 | int dwarf64_p; |
1468 | ULONGEST cie_id; | |
cfc14b3a | 1469 | ULONGEST cie_pointer; |
cfc14b3a | 1470 | |
6896c0c7 | 1471 | buf = start; |
cfc14b3a MK |
1472 | length = read_initial_length (unit->abfd, buf, &bytes_read); |
1473 | buf += bytes_read; | |
1474 | end = buf + length; | |
1475 | ||
6896c0c7 RH |
1476 | /* Are we still within the section? */ |
1477 | if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size) | |
1478 | return NULL; | |
1479 | ||
cfc14b3a MK |
1480 | if (length == 0) |
1481 | return end; | |
1482 | ||
6896c0c7 RH |
1483 | /* Distinguish between 32 and 64-bit encoded frame info. */ |
1484 | dwarf64_p = (bytes_read == 12); | |
cfc14b3a | 1485 | |
6896c0c7 | 1486 | /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */ |
cfc14b3a MK |
1487 | if (eh_frame_p) |
1488 | cie_id = 0; | |
1489 | else if (dwarf64_p) | |
1490 | cie_id = DW64_CIE_ID; | |
6896c0c7 RH |
1491 | else |
1492 | cie_id = DW_CIE_ID; | |
cfc14b3a MK |
1493 | |
1494 | if (dwarf64_p) | |
1495 | { | |
1496 | cie_pointer = read_8_bytes (unit->abfd, buf); | |
1497 | buf += 8; | |
1498 | } | |
1499 | else | |
1500 | { | |
1501 | cie_pointer = read_4_bytes (unit->abfd, buf); | |
1502 | buf += 4; | |
1503 | } | |
1504 | ||
1505 | if (cie_pointer == cie_id) | |
1506 | { | |
1507 | /* This is a CIE. */ | |
1508 | struct dwarf2_cie *cie; | |
1509 | char *augmentation; | |
28ba0b33 | 1510 | unsigned int cie_version; |
cfc14b3a MK |
1511 | |
1512 | /* Record the offset into the .debug_frame section of this CIE. */ | |
1513 | cie_pointer = start - unit->dwarf_frame_buffer; | |
1514 | ||
1515 | /* Check whether we've already read it. */ | |
1516 | if (find_cie (unit, cie_pointer)) | |
1517 | return end; | |
1518 | ||
1519 | cie = (struct dwarf2_cie *) | |
8b92e4d5 | 1520 | obstack_alloc (&unit->objfile->objfile_obstack, |
cfc14b3a MK |
1521 | sizeof (struct dwarf2_cie)); |
1522 | cie->initial_instructions = NULL; | |
1523 | cie->cie_pointer = cie_pointer; | |
1524 | ||
1525 | /* The encoding for FDE's in a normal .debug_frame section | |
32b05c07 MK |
1526 | depends on the target address size. */ |
1527 | cie->encoding = DW_EH_PE_absptr; | |
cfc14b3a | 1528 | |
56c987f6 AO |
1529 | /* We'll determine the final value later, but we need to |
1530 | initialize it conservatively. */ | |
1531 | cie->signal_frame = 0; | |
1532 | ||
cfc14b3a | 1533 | /* Check version number. */ |
28ba0b33 PB |
1534 | cie_version = read_1_byte (unit->abfd, buf); |
1535 | if (cie_version != 1 && cie_version != 3) | |
6896c0c7 | 1536 | return NULL; |
cfc14b3a MK |
1537 | buf += 1; |
1538 | ||
1539 | /* Interpret the interesting bits of the augmentation. */ | |
852483bc MK |
1540 | augmentation = (char *) buf; |
1541 | buf += (strlen (augmentation) + 1); | |
cfc14b3a MK |
1542 | |
1543 | /* The GCC 2.x "eh" augmentation has a pointer immediately | |
1544 | following the augmentation string, so it must be handled | |
1545 | first. */ | |
1546 | if (augmentation[0] == 'e' && augmentation[1] == 'h') | |
1547 | { | |
1548 | /* Skip. */ | |
1549 | buf += TYPE_LENGTH (builtin_type_void_data_ptr); | |
1550 | augmentation += 2; | |
1551 | } | |
1552 | ||
1553 | cie->code_alignment_factor = | |
1554 | read_unsigned_leb128 (unit->abfd, buf, &bytes_read); | |
1555 | buf += bytes_read; | |
1556 | ||
1557 | cie->data_alignment_factor = | |
1558 | read_signed_leb128 (unit->abfd, buf, &bytes_read); | |
1559 | buf += bytes_read; | |
1560 | ||
28ba0b33 PB |
1561 | if (cie_version == 1) |
1562 | { | |
1563 | cie->return_address_register = read_1_byte (unit->abfd, buf); | |
1564 | bytes_read = 1; | |
1565 | } | |
1566 | else | |
1567 | cie->return_address_register = read_unsigned_leb128 (unit->abfd, buf, | |
1568 | &bytes_read); | |
4bf8967c AS |
1569 | if (eh_frame_p) |
1570 | cie->return_address_register | |
1571 | = dwarf2_frame_eh_frame_regnum (current_gdbarch, | |
1572 | cie->return_address_register); | |
1573 | ||
28ba0b33 | 1574 | buf += bytes_read; |
cfc14b3a | 1575 | |
7131cb6e RH |
1576 | cie->saw_z_augmentation = (*augmentation == 'z'); |
1577 | if (cie->saw_z_augmentation) | |
cfc14b3a MK |
1578 | { |
1579 | ULONGEST length; | |
1580 | ||
1581 | length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read); | |
1582 | buf += bytes_read; | |
6896c0c7 RH |
1583 | if (buf > end) |
1584 | return NULL; | |
cfc14b3a MK |
1585 | cie->initial_instructions = buf + length; |
1586 | augmentation++; | |
1587 | } | |
1588 | ||
1589 | while (*augmentation) | |
1590 | { | |
1591 | /* "L" indicates a byte showing how the LSDA pointer is encoded. */ | |
1592 | if (*augmentation == 'L') | |
1593 | { | |
1594 | /* Skip. */ | |
1595 | buf++; | |
1596 | augmentation++; | |
1597 | } | |
1598 | ||
1599 | /* "R" indicates a byte indicating how FDE addresses are encoded. */ | |
1600 | else if (*augmentation == 'R') | |
1601 | { | |
1602 | cie->encoding = *buf++; | |
1603 | augmentation++; | |
1604 | } | |
1605 | ||
1606 | /* "P" indicates a personality routine in the CIE augmentation. */ | |
1607 | else if (*augmentation == 'P') | |
1608 | { | |
1234d960 | 1609 | /* Skip. Avoid indirection since we throw away the result. */ |
852483bc | 1610 | gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect; |
f724bf08 MK |
1611 | read_encoded_value (unit, encoding, buf, &bytes_read); |
1612 | buf += bytes_read; | |
cfc14b3a MK |
1613 | augmentation++; |
1614 | } | |
1615 | ||
56c987f6 AO |
1616 | /* "S" indicates a signal frame, such that the return |
1617 | address must not be decremented to locate the call frame | |
1618 | info for the previous frame; it might even be the first | |
1619 | instruction of a function, so decrementing it would take | |
1620 | us to a different function. */ | |
1621 | else if (*augmentation == 'S') | |
1622 | { | |
1623 | cie->signal_frame = 1; | |
1624 | augmentation++; | |
1625 | } | |
1626 | ||
cfc14b3a MK |
1627 | /* Otherwise we have an unknown augmentation. |
1628 | Bail out unless we saw a 'z' prefix. */ | |
1629 | else | |
1630 | { | |
1631 | if (cie->initial_instructions == NULL) | |
1632 | return end; | |
1633 | ||
1634 | /* Skip unknown augmentations. */ | |
1635 | buf = cie->initial_instructions; | |
1636 | break; | |
1637 | } | |
1638 | } | |
1639 | ||
1640 | cie->initial_instructions = buf; | |
1641 | cie->end = end; | |
1642 | ||
1643 | add_cie (unit, cie); | |
1644 | } | |
1645 | else | |
1646 | { | |
1647 | /* This is a FDE. */ | |
1648 | struct dwarf2_fde *fde; | |
1649 | ||
6896c0c7 RH |
1650 | /* In an .eh_frame section, the CIE pointer is the delta between the |
1651 | address within the FDE where the CIE pointer is stored and the | |
1652 | address of the CIE. Convert it to an offset into the .eh_frame | |
1653 | section. */ | |
cfc14b3a MK |
1654 | if (eh_frame_p) |
1655 | { | |
cfc14b3a MK |
1656 | cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer; |
1657 | cie_pointer -= (dwarf64_p ? 8 : 4); | |
1658 | } | |
1659 | ||
6896c0c7 RH |
1660 | /* In either case, validate the result is still within the section. */ |
1661 | if (cie_pointer >= unit->dwarf_frame_size) | |
1662 | return NULL; | |
1663 | ||
cfc14b3a | 1664 | fde = (struct dwarf2_fde *) |
8b92e4d5 | 1665 | obstack_alloc (&unit->objfile->objfile_obstack, |
cfc14b3a MK |
1666 | sizeof (struct dwarf2_fde)); |
1667 | fde->cie = find_cie (unit, cie_pointer); | |
1668 | if (fde->cie == NULL) | |
1669 | { | |
1670 | decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer, | |
1671 | eh_frame_p); | |
1672 | fde->cie = find_cie (unit, cie_pointer); | |
1673 | } | |
1674 | ||
1675 | gdb_assert (fde->cie != NULL); | |
1676 | ||
1677 | fde->initial_location = | |
1678 | read_encoded_value (unit, fde->cie->encoding, buf, &bytes_read); | |
1679 | buf += bytes_read; | |
1680 | ||
1681 | fde->address_range = | |
1682 | read_encoded_value (unit, fde->cie->encoding & 0x0f, buf, &bytes_read); | |
1683 | buf += bytes_read; | |
1684 | ||
7131cb6e RH |
1685 | /* A 'z' augmentation in the CIE implies the presence of an |
1686 | augmentation field in the FDE as well. The only thing known | |
1687 | to be in here at present is the LSDA entry for EH. So we | |
1688 | can skip the whole thing. */ | |
1689 | if (fde->cie->saw_z_augmentation) | |
1690 | { | |
1691 | ULONGEST length; | |
1692 | ||
1693 | length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read); | |
1694 | buf += bytes_read + length; | |
6896c0c7 RH |
1695 | if (buf > end) |
1696 | return NULL; | |
7131cb6e RH |
1697 | } |
1698 | ||
cfc14b3a MK |
1699 | fde->instructions = buf; |
1700 | fde->end = end; | |
1701 | ||
4bf8967c AS |
1702 | fde->eh_frame_p = eh_frame_p; |
1703 | ||
cfc14b3a MK |
1704 | add_fde (unit, fde); |
1705 | } | |
1706 | ||
1707 | return end; | |
1708 | } | |
6896c0c7 RH |
1709 | |
1710 | /* Read a CIE or FDE in BUF and decode it. */ | |
852483bc MK |
1711 | static gdb_byte * |
1712 | decode_frame_entry (struct comp_unit *unit, gdb_byte *start, int eh_frame_p) | |
6896c0c7 RH |
1713 | { |
1714 | enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE; | |
852483bc | 1715 | gdb_byte *ret; |
6896c0c7 RH |
1716 | const char *msg; |
1717 | ptrdiff_t start_offset; | |
1718 | ||
1719 | while (1) | |
1720 | { | |
1721 | ret = decode_frame_entry_1 (unit, start, eh_frame_p); | |
1722 | if (ret != NULL) | |
1723 | break; | |
1724 | ||
1725 | /* We have corrupt input data of some form. */ | |
1726 | ||
1727 | /* ??? Try, weakly, to work around compiler/assembler/linker bugs | |
1728 | and mismatches wrt padding and alignment of debug sections. */ | |
1729 | /* Note that there is no requirement in the standard for any | |
1730 | alignment at all in the frame unwind sections. Testing for | |
1731 | alignment before trying to interpret data would be incorrect. | |
1732 | ||
1733 | However, GCC traditionally arranged for frame sections to be | |
1734 | sized such that the FDE length and CIE fields happen to be | |
1735 | aligned (in theory, for performance). This, unfortunately, | |
1736 | was done with .align directives, which had the side effect of | |
1737 | forcing the section to be aligned by the linker. | |
1738 | ||
1739 | This becomes a problem when you have some other producer that | |
1740 | creates frame sections that are not as strictly aligned. That | |
1741 | produces a hole in the frame info that gets filled by the | |
1742 | linker with zeros. | |
1743 | ||
1744 | The GCC behaviour is arguably a bug, but it's effectively now | |
1745 | part of the ABI, so we're now stuck with it, at least at the | |
1746 | object file level. A smart linker may decide, in the process | |
1747 | of compressing duplicate CIE information, that it can rewrite | |
1748 | the entire output section without this extra padding. */ | |
1749 | ||
1750 | start_offset = start - unit->dwarf_frame_buffer; | |
1751 | if (workaround < ALIGN4 && (start_offset & 3) != 0) | |
1752 | { | |
1753 | start += 4 - (start_offset & 3); | |
1754 | workaround = ALIGN4; | |
1755 | continue; | |
1756 | } | |
1757 | if (workaround < ALIGN8 && (start_offset & 7) != 0) | |
1758 | { | |
1759 | start += 8 - (start_offset & 7); | |
1760 | workaround = ALIGN8; | |
1761 | continue; | |
1762 | } | |
1763 | ||
1764 | /* Nothing left to try. Arrange to return as if we've consumed | |
1765 | the entire input section. Hopefully we'll get valid info from | |
1766 | the other of .debug_frame/.eh_frame. */ | |
1767 | workaround = FAIL; | |
1768 | ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size; | |
1769 | break; | |
1770 | } | |
1771 | ||
1772 | switch (workaround) | |
1773 | { | |
1774 | case NONE: | |
1775 | break; | |
1776 | ||
1777 | case ALIGN4: | |
1778 | complaint (&symfile_complaints, | |
e2e0b3e5 | 1779 | _("Corrupt data in %s:%s; align 4 workaround apparently succeeded"), |
6896c0c7 RH |
1780 | unit->dwarf_frame_section->owner->filename, |
1781 | unit->dwarf_frame_section->name); | |
1782 | break; | |
1783 | ||
1784 | case ALIGN8: | |
1785 | complaint (&symfile_complaints, | |
e2e0b3e5 | 1786 | _("Corrupt data in %s:%s; align 8 workaround apparently succeeded"), |
6896c0c7 RH |
1787 | unit->dwarf_frame_section->owner->filename, |
1788 | unit->dwarf_frame_section->name); | |
1789 | break; | |
1790 | ||
1791 | default: | |
1792 | complaint (&symfile_complaints, | |
e2e0b3e5 | 1793 | _("Corrupt data in %s:%s"), |
6896c0c7 RH |
1794 | unit->dwarf_frame_section->owner->filename, |
1795 | unit->dwarf_frame_section->name); | |
1796 | break; | |
1797 | } | |
1798 | ||
1799 | return ret; | |
1800 | } | |
cfc14b3a MK |
1801 | \f |
1802 | ||
1803 | /* FIXME: kettenis/20030504: This still needs to be integrated with | |
1804 | dwarf2read.c in a better way. */ | |
1805 | ||
1806 | /* Imported from dwarf2read.c. */ | |
cfc14b3a | 1807 | extern asection *dwarf_frame_section; |
cfc14b3a MK |
1808 | extern asection *dwarf_eh_frame_section; |
1809 | ||
1810 | /* Imported from dwarf2read.c. */ | |
1193688d | 1811 | extern gdb_byte *dwarf2_read_section (struct objfile *objfile, asection *sectp); |
cfc14b3a MK |
1812 | |
1813 | void | |
1814 | dwarf2_build_frame_info (struct objfile *objfile) | |
1815 | { | |
1816 | struct comp_unit unit; | |
852483bc | 1817 | gdb_byte *frame_ptr; |
cfc14b3a MK |
1818 | |
1819 | /* Build a minimal decoding of the DWARF2 compilation unit. */ | |
1820 | unit.abfd = objfile->obfd; | |
1821 | unit.objfile = objfile; | |
0912c7f2 | 1822 | unit.dbase = 0; |
0fd85043 | 1823 | unit.tbase = 0; |
cfc14b3a MK |
1824 | |
1825 | /* First add the information from the .eh_frame section. That way, | |
1826 | the FDEs from that section are searched last. */ | |
188dd5d6 | 1827 | if (dwarf_eh_frame_section) |
cfc14b3a | 1828 | { |
0fd85043 | 1829 | asection *got, *txt; |
0912c7f2 | 1830 | |
cfc14b3a MK |
1831 | unit.cie = NULL; |
1832 | unit.dwarf_frame_buffer = dwarf2_read_section (objfile, | |
cfc14b3a MK |
1833 | dwarf_eh_frame_section); |
1834 | ||
2c500098 | 1835 | unit.dwarf_frame_size = bfd_get_section_size (dwarf_eh_frame_section); |
cfc14b3a MK |
1836 | unit.dwarf_frame_section = dwarf_eh_frame_section; |
1837 | ||
0912c7f2 | 1838 | /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base |
37b517aa MK |
1839 | that is used for the i386/amd64 target, which currently is |
1840 | the only target in GCC that supports/uses the | |
1841 | DW_EH_PE_datarel encoding. */ | |
0912c7f2 MK |
1842 | got = bfd_get_section_by_name (unit.abfd, ".got"); |
1843 | if (got) | |
1844 | unit.dbase = got->vma; | |
1845 | ||
22c7ba1a MK |
1846 | /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64 |
1847 | so far. */ | |
0fd85043 CV |
1848 | txt = bfd_get_section_by_name (unit.abfd, ".text"); |
1849 | if (txt) | |
1850 | unit.tbase = txt->vma; | |
1851 | ||
cfc14b3a MK |
1852 | frame_ptr = unit.dwarf_frame_buffer; |
1853 | while (frame_ptr < unit.dwarf_frame_buffer + unit.dwarf_frame_size) | |
1854 | frame_ptr = decode_frame_entry (&unit, frame_ptr, 1); | |
1855 | } | |
1856 | ||
188dd5d6 | 1857 | if (dwarf_frame_section) |
cfc14b3a MK |
1858 | { |
1859 | unit.cie = NULL; | |
1860 | unit.dwarf_frame_buffer = dwarf2_read_section (objfile, | |
cfc14b3a | 1861 | dwarf_frame_section); |
2c500098 | 1862 | unit.dwarf_frame_size = bfd_get_section_size (dwarf_frame_section); |
cfc14b3a MK |
1863 | unit.dwarf_frame_section = dwarf_frame_section; |
1864 | ||
1865 | frame_ptr = unit.dwarf_frame_buffer; | |
1866 | while (frame_ptr < unit.dwarf_frame_buffer + unit.dwarf_frame_size) | |
1867 | frame_ptr = decode_frame_entry (&unit, frame_ptr, 0); | |
1868 | } | |
1869 | } | |
0d0e1a63 MK |
1870 | |
1871 | /* Provide a prototype to silence -Wmissing-prototypes. */ | |
1872 | void _initialize_dwarf2_frame (void); | |
1873 | ||
1874 | void | |
1875 | _initialize_dwarf2_frame (void) | |
1876 | { | |
030f20e1 | 1877 | dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init); |
8f22cb90 | 1878 | dwarf2_frame_objfile_data = register_objfile_data (); |
0d0e1a63 | 1879 | } |