Commit | Line | Data |
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cfc14b3a MK |
1 | /* Frame unwinder for frames with DWARF Call Frame Information. |
2 | ||
8d5a9abc | 3 | Copyright 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 | |
21 | Foundation, Inc., 59 Temple Place - Suite 330, | |
22 | Boston, MA 02111-1307, USA. */ | |
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" | |
35 | ||
36 | #include "gdb_assert.h" | |
37 | #include "gdb_string.h" | |
38 | ||
6896c0c7 | 39 | #include "complaints.h" |
cfc14b3a MK |
40 | #include "dwarf2-frame.h" |
41 | ||
42 | /* Call Frame Information (CFI). */ | |
43 | ||
44 | /* Common Information Entry (CIE). */ | |
45 | ||
46 | struct dwarf2_cie | |
47 | { | |
48 | /* Offset into the .debug_frame section where this CIE was found. | |
49 | Used to identify this CIE. */ | |
50 | ULONGEST cie_pointer; | |
51 | ||
52 | /* Constant that is factored out of all advance location | |
53 | instructions. */ | |
54 | ULONGEST code_alignment_factor; | |
55 | ||
56 | /* Constants that is factored out of all offset instructions. */ | |
57 | LONGEST data_alignment_factor; | |
58 | ||
59 | /* Return address column. */ | |
60 | ULONGEST return_address_register; | |
61 | ||
62 | /* Instruction sequence to initialize a register set. */ | |
852483bc MK |
63 | gdb_byte *initial_instructions; |
64 | gdb_byte *end; | |
cfc14b3a MK |
65 | |
66 | /* Encoding of addresses. */ | |
852483bc | 67 | gdb_byte encoding; |
cfc14b3a | 68 | |
7131cb6e RH |
69 | /* True if a 'z' augmentation existed. */ |
70 | unsigned char saw_z_augmentation; | |
71 | ||
cfc14b3a MK |
72 | struct dwarf2_cie *next; |
73 | }; | |
74 | ||
75 | /* Frame Description Entry (FDE). */ | |
76 | ||
77 | struct dwarf2_fde | |
78 | { | |
79 | /* CIE for this FDE. */ | |
80 | struct dwarf2_cie *cie; | |
81 | ||
82 | /* First location associated with this FDE. */ | |
83 | CORE_ADDR initial_location; | |
84 | ||
85 | /* Number of bytes of program instructions described by this FDE. */ | |
86 | CORE_ADDR address_range; | |
87 | ||
88 | /* Instruction sequence. */ | |
852483bc MK |
89 | gdb_byte *instructions; |
90 | gdb_byte *end; | |
cfc14b3a MK |
91 | |
92 | struct dwarf2_fde *next; | |
93 | }; | |
94 | ||
95 | static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc); | |
96 | \f | |
97 | ||
98 | /* Structure describing a frame state. */ | |
99 | ||
100 | struct dwarf2_frame_state | |
101 | { | |
102 | /* Each register save state can be described in terms of a CFA slot, | |
103 | another register, or a location expression. */ | |
104 | struct dwarf2_frame_state_reg_info | |
105 | { | |
05cbe71a | 106 | struct dwarf2_frame_state_reg *reg; |
cfc14b3a MK |
107 | int num_regs; |
108 | ||
109 | /* Used to implement DW_CFA_remember_state. */ | |
110 | struct dwarf2_frame_state_reg_info *prev; | |
111 | } regs; | |
112 | ||
113 | LONGEST cfa_offset; | |
114 | ULONGEST cfa_reg; | |
852483bc | 115 | gdb_byte *cfa_exp; |
cfc14b3a MK |
116 | enum { |
117 | CFA_UNSET, | |
118 | CFA_REG_OFFSET, | |
119 | CFA_EXP | |
120 | } cfa_how; | |
121 | ||
122 | /* The PC described by the current frame state. */ | |
123 | CORE_ADDR pc; | |
124 | ||
125 | /* Initial register set from the CIE. | |
126 | Used to implement DW_CFA_restore. */ | |
127 | struct dwarf2_frame_state_reg_info initial; | |
128 | ||
129 | /* The information we care about from the CIE. */ | |
130 | LONGEST data_align; | |
131 | ULONGEST code_align; | |
132 | ULONGEST retaddr_column; | |
133 | }; | |
134 | ||
135 | /* Store the length the expression for the CFA in the `cfa_reg' field, | |
136 | which is unused in that case. */ | |
137 | #define cfa_exp_len cfa_reg | |
138 | ||
139 | /* Assert that the register set RS is large enough to store NUM_REGS | |
140 | columns. If necessary, enlarge the register set. */ | |
141 | ||
142 | static void | |
143 | dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs, | |
144 | int num_regs) | |
145 | { | |
146 | size_t size = sizeof (struct dwarf2_frame_state_reg); | |
147 | ||
148 | if (num_regs <= rs->num_regs) | |
149 | return; | |
150 | ||
151 | rs->reg = (struct dwarf2_frame_state_reg *) | |
152 | xrealloc (rs->reg, num_regs * size); | |
153 | ||
154 | /* Initialize newly allocated registers. */ | |
2473a4a9 | 155 | memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size); |
cfc14b3a MK |
156 | rs->num_regs = num_regs; |
157 | } | |
158 | ||
159 | /* Copy the register columns in register set RS into newly allocated | |
160 | memory and return a pointer to this newly created copy. */ | |
161 | ||
162 | static struct dwarf2_frame_state_reg * | |
163 | dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs) | |
164 | { | |
d10891d4 | 165 | size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg); |
cfc14b3a MK |
166 | struct dwarf2_frame_state_reg *reg; |
167 | ||
168 | reg = (struct dwarf2_frame_state_reg *) xmalloc (size); | |
169 | memcpy (reg, rs->reg, size); | |
170 | ||
171 | return reg; | |
172 | } | |
173 | ||
174 | /* Release the memory allocated to register set RS. */ | |
175 | ||
176 | static void | |
177 | dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs) | |
178 | { | |
179 | if (rs) | |
180 | { | |
181 | dwarf2_frame_state_free_regs (rs->prev); | |
182 | ||
183 | xfree (rs->reg); | |
184 | xfree (rs); | |
185 | } | |
186 | } | |
187 | ||
188 | /* Release the memory allocated to the frame state FS. */ | |
189 | ||
190 | static void | |
191 | dwarf2_frame_state_free (void *p) | |
192 | { | |
193 | struct dwarf2_frame_state *fs = p; | |
194 | ||
195 | dwarf2_frame_state_free_regs (fs->initial.prev); | |
196 | dwarf2_frame_state_free_regs (fs->regs.prev); | |
197 | xfree (fs->initial.reg); | |
198 | xfree (fs->regs.reg); | |
199 | xfree (fs); | |
200 | } | |
201 | \f | |
202 | ||
203 | /* Helper functions for execute_stack_op. */ | |
204 | ||
205 | static CORE_ADDR | |
206 | read_reg (void *baton, int reg) | |
207 | { | |
208 | struct frame_info *next_frame = (struct frame_info *) baton; | |
05cbe71a | 209 | struct gdbarch *gdbarch = get_frame_arch (next_frame); |
cfc14b3a | 210 | int regnum; |
852483bc | 211 | gdb_byte *buf; |
cfc14b3a MK |
212 | |
213 | regnum = DWARF2_REG_TO_REGNUM (reg); | |
214 | ||
852483bc | 215 | buf = alloca (register_size (gdbarch, regnum)); |
cfc14b3a MK |
216 | frame_unwind_register (next_frame, regnum, buf); |
217 | return extract_typed_address (buf, builtin_type_void_data_ptr); | |
218 | } | |
219 | ||
220 | static void | |
852483bc | 221 | read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
cfc14b3a MK |
222 | { |
223 | read_memory (addr, buf, len); | |
224 | } | |
225 | ||
226 | static void | |
852483bc | 227 | no_get_frame_base (void *baton, gdb_byte **start, size_t *length) |
cfc14b3a MK |
228 | { |
229 | internal_error (__FILE__, __LINE__, | |
e2e0b3e5 | 230 | _("Support for DW_OP_fbreg is unimplemented")); |
cfc14b3a MK |
231 | } |
232 | ||
233 | static CORE_ADDR | |
234 | no_get_tls_address (void *baton, CORE_ADDR offset) | |
235 | { | |
236 | internal_error (__FILE__, __LINE__, | |
e2e0b3e5 | 237 | _("Support for DW_OP_GNU_push_tls_address is unimplemented")); |
cfc14b3a MK |
238 | } |
239 | ||
240 | static CORE_ADDR | |
852483bc | 241 | execute_stack_op (gdb_byte *exp, ULONGEST len, |
cfc14b3a MK |
242 | struct frame_info *next_frame, CORE_ADDR initial) |
243 | { | |
244 | struct dwarf_expr_context *ctx; | |
245 | CORE_ADDR result; | |
246 | ||
247 | ctx = new_dwarf_expr_context (); | |
248 | ctx->baton = next_frame; | |
249 | ctx->read_reg = read_reg; | |
250 | ctx->read_mem = read_mem; | |
251 | ctx->get_frame_base = no_get_frame_base; | |
252 | ctx->get_tls_address = no_get_tls_address; | |
253 | ||
254 | dwarf_expr_push (ctx, initial); | |
255 | dwarf_expr_eval (ctx, exp, len); | |
256 | result = dwarf_expr_fetch (ctx, 0); | |
257 | ||
258 | if (ctx->in_reg) | |
259 | result = read_reg (next_frame, result); | |
260 | ||
261 | free_dwarf_expr_context (ctx); | |
262 | ||
263 | return result; | |
264 | } | |
265 | \f | |
266 | ||
267 | static void | |
852483bc | 268 | execute_cfa_program (gdb_byte *insn_ptr, gdb_byte *insn_end, |
cfc14b3a MK |
269 | struct frame_info *next_frame, |
270 | struct dwarf2_frame_state *fs) | |
271 | { | |
272 | CORE_ADDR pc = frame_pc_unwind (next_frame); | |
273 | int bytes_read; | |
274 | ||
275 | while (insn_ptr < insn_end && fs->pc <= pc) | |
276 | { | |
852483bc | 277 | gdb_byte insn = *insn_ptr++; |
cfc14b3a MK |
278 | ULONGEST utmp, reg; |
279 | LONGEST offset; | |
280 | ||
281 | if ((insn & 0xc0) == DW_CFA_advance_loc) | |
282 | fs->pc += (insn & 0x3f) * fs->code_align; | |
283 | else if ((insn & 0xc0) == DW_CFA_offset) | |
284 | { | |
285 | reg = insn & 0x3f; | |
286 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
287 | offset = utmp * fs->data_align; | |
288 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
05cbe71a | 289 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
cfc14b3a MK |
290 | fs->regs.reg[reg].loc.offset = offset; |
291 | } | |
292 | else if ((insn & 0xc0) == DW_CFA_restore) | |
293 | { | |
294 | gdb_assert (fs->initial.reg); | |
295 | reg = insn & 0x3f; | |
296 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
297 | fs->regs.reg[reg] = fs->initial.reg[reg]; | |
298 | } | |
299 | else | |
300 | { | |
301 | switch (insn) | |
302 | { | |
303 | case DW_CFA_set_loc: | |
304 | fs->pc = dwarf2_read_address (insn_ptr, insn_end, &bytes_read); | |
305 | insn_ptr += bytes_read; | |
306 | break; | |
307 | ||
308 | case DW_CFA_advance_loc1: | |
309 | utmp = extract_unsigned_integer (insn_ptr, 1); | |
310 | fs->pc += utmp * fs->code_align; | |
311 | insn_ptr++; | |
312 | break; | |
313 | case DW_CFA_advance_loc2: | |
314 | utmp = extract_unsigned_integer (insn_ptr, 2); | |
315 | fs->pc += utmp * fs->code_align; | |
316 | insn_ptr += 2; | |
317 | break; | |
318 | case DW_CFA_advance_loc4: | |
319 | utmp = extract_unsigned_integer (insn_ptr, 4); | |
320 | fs->pc += utmp * fs->code_align; | |
321 | insn_ptr += 4; | |
322 | break; | |
323 | ||
324 | case DW_CFA_offset_extended: | |
325 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
326 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
327 | offset = utmp * fs->data_align; | |
328 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
05cbe71a | 329 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
cfc14b3a MK |
330 | fs->regs.reg[reg].loc.offset = offset; |
331 | break; | |
332 | ||
333 | case DW_CFA_restore_extended: | |
334 | gdb_assert (fs->initial.reg); | |
335 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
336 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
337 | fs->regs.reg[reg] = fs->initial.reg[reg]; | |
338 | break; | |
339 | ||
340 | case DW_CFA_undefined: | |
341 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
342 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
05cbe71a | 343 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED; |
cfc14b3a MK |
344 | break; |
345 | ||
346 | case DW_CFA_same_value: | |
347 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
348 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
05cbe71a | 349 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE; |
cfc14b3a MK |
350 | break; |
351 | ||
352 | case DW_CFA_register: | |
353 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
354 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
355 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
05cbe71a | 356 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG; |
cfc14b3a MK |
357 | fs->regs.reg[reg].loc.reg = utmp; |
358 | break; | |
359 | ||
360 | case DW_CFA_remember_state: | |
361 | { | |
362 | struct dwarf2_frame_state_reg_info *new_rs; | |
363 | ||
364 | new_rs = XMALLOC (struct dwarf2_frame_state_reg_info); | |
365 | *new_rs = fs->regs; | |
366 | fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs); | |
367 | fs->regs.prev = new_rs; | |
368 | } | |
369 | break; | |
370 | ||
371 | case DW_CFA_restore_state: | |
372 | { | |
373 | struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev; | |
374 | ||
50ea7769 MK |
375 | if (old_rs == NULL) |
376 | { | |
e2e0b3e5 AC |
377 | complaint (&symfile_complaints, _("\ |
378 | bad CFI data; mismatched DW_CFA_restore_state at 0x%s"), paddr (fs->pc)); | |
50ea7769 MK |
379 | } |
380 | else | |
381 | { | |
382 | xfree (fs->regs.reg); | |
383 | fs->regs = *old_rs; | |
384 | xfree (old_rs); | |
385 | } | |
cfc14b3a MK |
386 | } |
387 | break; | |
388 | ||
389 | case DW_CFA_def_cfa: | |
390 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); | |
391 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
392 | fs->cfa_offset = utmp; | |
393 | fs->cfa_how = CFA_REG_OFFSET; | |
394 | break; | |
395 | ||
396 | case DW_CFA_def_cfa_register: | |
397 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); | |
398 | fs->cfa_how = CFA_REG_OFFSET; | |
399 | break; | |
400 | ||
401 | case DW_CFA_def_cfa_offset: | |
852483bc MK |
402 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
403 | fs->cfa_offset = utmp; | |
cfc14b3a MK |
404 | /* cfa_how deliberately not set. */ |
405 | break; | |
406 | ||
a8504492 MK |
407 | case DW_CFA_nop: |
408 | break; | |
409 | ||
cfc14b3a MK |
410 | case DW_CFA_def_cfa_expression: |
411 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_exp_len); | |
412 | fs->cfa_exp = insn_ptr; | |
413 | fs->cfa_how = CFA_EXP; | |
414 | insn_ptr += fs->cfa_exp_len; | |
415 | break; | |
416 | ||
417 | case DW_CFA_expression: | |
418 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
419 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
420 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
421 | fs->regs.reg[reg].loc.exp = insn_ptr; | |
422 | fs->regs.reg[reg].exp_len = utmp; | |
05cbe71a | 423 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP; |
cfc14b3a MK |
424 | insn_ptr += utmp; |
425 | break; | |
426 | ||
a8504492 MK |
427 | case DW_CFA_offset_extended_sf: |
428 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
429 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); | |
f6da8dd8 | 430 | offset *= fs->data_align; |
a8504492 | 431 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
05cbe71a | 432 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
a8504492 MK |
433 | fs->regs.reg[reg].loc.offset = offset; |
434 | break; | |
435 | ||
436 | case DW_CFA_def_cfa_sf: | |
437 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); | |
438 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); | |
439 | fs->cfa_offset = offset * fs->data_align; | |
440 | fs->cfa_how = CFA_REG_OFFSET; | |
441 | break; | |
442 | ||
443 | case DW_CFA_def_cfa_offset_sf: | |
444 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); | |
445 | fs->cfa_offset = offset * fs->data_align; | |
446 | /* cfa_how deliberately not set. */ | |
cfc14b3a MK |
447 | break; |
448 | ||
a77f4086 MK |
449 | case DW_CFA_GNU_window_save: |
450 | /* This is SPARC-specific code, and contains hard-coded | |
451 | constants for the register numbering scheme used by | |
452 | GCC. Rather than having a architecture-specific | |
453 | operation that's only ever used by a single | |
454 | architecture, we provide the implementation here. | |
455 | Incidentally that's what GCC does too in its | |
456 | unwinder. */ | |
457 | { | |
458 | struct gdbarch *gdbarch = get_frame_arch (next_frame); | |
459 | int size = register_size(gdbarch, 0); | |
460 | dwarf2_frame_state_alloc_regs (&fs->regs, 32); | |
461 | for (reg = 8; reg < 16; reg++) | |
462 | { | |
463 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG; | |
464 | fs->regs.reg[reg].loc.reg = reg + 16; | |
465 | } | |
466 | for (reg = 16; reg < 32; reg++) | |
467 | { | |
468 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; | |
469 | fs->regs.reg[reg].loc.offset = (reg - 16) * size; | |
470 | } | |
471 | } | |
472 | break; | |
473 | ||
cfc14b3a MK |
474 | case DW_CFA_GNU_args_size: |
475 | /* Ignored. */ | |
476 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
477 | break; | |
478 | ||
479 | default: | |
e2e0b3e5 | 480 | internal_error (__FILE__, __LINE__, _("Unknown CFI encountered.")); |
cfc14b3a MK |
481 | } |
482 | } | |
483 | } | |
484 | ||
485 | /* Don't allow remember/restore between CIE and FDE programs. */ | |
486 | dwarf2_frame_state_free_regs (fs->regs.prev); | |
487 | fs->regs.prev = NULL; | |
488 | } | |
8f22cb90 | 489 | \f |
cfc14b3a | 490 | |
8f22cb90 | 491 | /* Architecture-specific operations. */ |
cfc14b3a | 492 | |
8f22cb90 MK |
493 | /* Per-architecture data key. */ |
494 | static struct gdbarch_data *dwarf2_frame_data; | |
495 | ||
496 | struct dwarf2_frame_ops | |
497 | { | |
498 | /* Pre-initialize the register state REG for register REGNUM. */ | |
499 | void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *); | |
3ed09a32 DJ |
500 | |
501 | /* Check whether the frame preceding NEXT_FRAME will be a signal | |
502 | trampoline. */ | |
503 | int (*signal_frame_p) (struct gdbarch *, struct frame_info *); | |
cfc14b3a MK |
504 | }; |
505 | ||
8f22cb90 MK |
506 | /* Default architecture-specific register state initialization |
507 | function. */ | |
508 | ||
509 | static void | |
510 | dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum, | |
511 | struct dwarf2_frame_state_reg *reg) | |
512 | { | |
513 | /* If we have a register that acts as a program counter, mark it as | |
514 | a destination for the return address. If we have a register that | |
515 | serves as the stack pointer, arrange for it to be filled with the | |
516 | call frame address (CFA). The other registers are marked as | |
517 | unspecified. | |
518 | ||
519 | We copy the return address to the program counter, since many | |
520 | parts in GDB assume that it is possible to get the return address | |
521 | by unwinding the program counter register. However, on ISA's | |
522 | with a dedicated return address register, the CFI usually only | |
523 | contains information to unwind that return address register. | |
524 | ||
525 | The reason we're treating the stack pointer special here is | |
526 | because in many cases GCC doesn't emit CFI for the stack pointer | |
527 | and implicitly assumes that it is equal to the CFA. This makes | |
528 | some sense since the DWARF specification (version 3, draft 8, | |
529 | p. 102) says that: | |
530 | ||
531 | "Typically, the CFA is defined to be the value of the stack | |
532 | pointer at the call site in the previous frame (which may be | |
533 | different from its value on entry to the current frame)." | |
534 | ||
535 | However, this isn't true for all platforms supported by GCC | |
536 | (e.g. IBM S/390 and zSeries). Those architectures should provide | |
537 | their own architecture-specific initialization function. */ | |
05cbe71a | 538 | |
8f22cb90 MK |
539 | if (regnum == PC_REGNUM) |
540 | reg->how = DWARF2_FRAME_REG_RA; | |
541 | else if (regnum == SP_REGNUM) | |
542 | reg->how = DWARF2_FRAME_REG_CFA; | |
543 | } | |
05cbe71a | 544 | |
8f22cb90 | 545 | /* Return a default for the architecture-specific operations. */ |
05cbe71a | 546 | |
8f22cb90 | 547 | static void * |
030f20e1 | 548 | dwarf2_frame_init (struct obstack *obstack) |
8f22cb90 MK |
549 | { |
550 | struct dwarf2_frame_ops *ops; | |
551 | ||
030f20e1 | 552 | ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops); |
8f22cb90 MK |
553 | ops->init_reg = dwarf2_frame_default_init_reg; |
554 | return ops; | |
555 | } | |
05cbe71a | 556 | |
8f22cb90 MK |
557 | /* Set the architecture-specific register state initialization |
558 | function for GDBARCH to INIT_REG. */ | |
559 | ||
560 | void | |
561 | dwarf2_frame_set_init_reg (struct gdbarch *gdbarch, | |
562 | void (*init_reg) (struct gdbarch *, int, | |
563 | struct dwarf2_frame_state_reg *)) | |
564 | { | |
030f20e1 | 565 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
8f22cb90 | 566 | |
8f22cb90 MK |
567 | ops->init_reg = init_reg; |
568 | } | |
569 | ||
570 | /* Pre-initialize the register state REG for register REGNUM. */ | |
05cbe71a MK |
571 | |
572 | static void | |
573 | dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum, | |
574 | struct dwarf2_frame_state_reg *reg) | |
575 | { | |
030f20e1 | 576 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
8f22cb90 | 577 | |
8f22cb90 | 578 | ops->init_reg (gdbarch, regnum, reg); |
05cbe71a | 579 | } |
3ed09a32 DJ |
580 | |
581 | /* Set the architecture-specific signal trampoline recognition | |
582 | function for GDBARCH to SIGNAL_FRAME_P. */ | |
583 | ||
584 | void | |
585 | dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch, | |
586 | int (*signal_frame_p) (struct gdbarch *, | |
587 | struct frame_info *)) | |
588 | { | |
589 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); | |
590 | ||
591 | ops->signal_frame_p = signal_frame_p; | |
592 | } | |
593 | ||
594 | /* Query the architecture-specific signal frame recognizer for | |
595 | NEXT_FRAME. */ | |
596 | ||
597 | static int | |
598 | dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch, | |
599 | struct frame_info *next_frame) | |
600 | { | |
601 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); | |
602 | ||
603 | if (ops->signal_frame_p == NULL) | |
604 | return 0; | |
605 | return ops->signal_frame_p (gdbarch, next_frame); | |
606 | } | |
8f22cb90 MK |
607 | \f |
608 | ||
609 | struct dwarf2_frame_cache | |
610 | { | |
611 | /* DWARF Call Frame Address. */ | |
612 | CORE_ADDR cfa; | |
613 | ||
0228dfb9 DJ |
614 | /* Set if the return address column was marked as undefined. */ |
615 | int undefined_retaddr; | |
616 | ||
8f22cb90 MK |
617 | /* Saved registers, indexed by GDB register number, not by DWARF |
618 | register number. */ | |
619 | struct dwarf2_frame_state_reg *reg; | |
8d5a9abc MK |
620 | |
621 | /* Return address register. */ | |
622 | struct dwarf2_frame_state_reg retaddr_reg; | |
8f22cb90 | 623 | }; |
05cbe71a | 624 | |
b9362cc7 | 625 | static struct dwarf2_frame_cache * |
cfc14b3a MK |
626 | dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache) |
627 | { | |
628 | struct cleanup *old_chain; | |
05cbe71a | 629 | struct gdbarch *gdbarch = get_frame_arch (next_frame); |
3e2c4033 | 630 | const int num_regs = NUM_REGS + NUM_PSEUDO_REGS; |
cfc14b3a MK |
631 | struct dwarf2_frame_cache *cache; |
632 | struct dwarf2_frame_state *fs; | |
633 | struct dwarf2_fde *fde; | |
cfc14b3a MK |
634 | |
635 | if (*this_cache) | |
636 | return *this_cache; | |
637 | ||
638 | /* Allocate a new cache. */ | |
639 | cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache); | |
640 | cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg); | |
641 | ||
642 | /* Allocate and initialize the frame state. */ | |
643 | fs = XMALLOC (struct dwarf2_frame_state); | |
644 | memset (fs, 0, sizeof (struct dwarf2_frame_state)); | |
645 | old_chain = make_cleanup (dwarf2_frame_state_free, fs); | |
646 | ||
647 | /* Unwind the PC. | |
648 | ||
649 | Note that if NEXT_FRAME is never supposed to return (i.e. a call | |
650 | to abort), the compiler might optimize away the instruction at | |
651 | NEXT_FRAME's return address. As a result the return address will | |
652 | point at some random instruction, and the CFI for that | |
e4e9607c | 653 | instruction is probably worthless to us. GCC's unwinder solves |
cfc14b3a MK |
654 | this problem by substracting 1 from the return address to get an |
655 | address in the middle of a presumed call instruction (or the | |
656 | instruction in the associated delay slot). This should only be | |
657 | done for "normal" frames and not for resume-type frames (signal | |
e4e9607c MK |
658 | handlers, sentinel frames, dummy frames). The function |
659 | frame_unwind_address_in_block does just this. It's not clear how | |
660 | reliable the method is though; there is the potential for the | |
661 | register state pre-call being different to that on return. */ | |
1ce5d6dd | 662 | fs->pc = frame_unwind_address_in_block (next_frame); |
cfc14b3a MK |
663 | |
664 | /* Find the correct FDE. */ | |
665 | fde = dwarf2_frame_find_fde (&fs->pc); | |
666 | gdb_assert (fde != NULL); | |
667 | ||
668 | /* Extract any interesting information from the CIE. */ | |
669 | fs->data_align = fde->cie->data_alignment_factor; | |
670 | fs->code_align = fde->cie->code_alignment_factor; | |
671 | fs->retaddr_column = fde->cie->return_address_register; | |
672 | ||
673 | /* First decode all the insns in the CIE. */ | |
674 | execute_cfa_program (fde->cie->initial_instructions, | |
675 | fde->cie->end, next_frame, fs); | |
676 | ||
677 | /* Save the initialized register set. */ | |
678 | fs->initial = fs->regs; | |
679 | fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs); | |
680 | ||
681 | /* Then decode the insns in the FDE up to our target PC. */ | |
682 | execute_cfa_program (fde->instructions, fde->end, next_frame, fs); | |
683 | ||
684 | /* Caclulate the CFA. */ | |
685 | switch (fs->cfa_how) | |
686 | { | |
687 | case CFA_REG_OFFSET: | |
688 | cache->cfa = read_reg (next_frame, fs->cfa_reg); | |
689 | cache->cfa += fs->cfa_offset; | |
690 | break; | |
691 | ||
692 | case CFA_EXP: | |
693 | cache->cfa = | |
694 | execute_stack_op (fs->cfa_exp, fs->cfa_exp_len, next_frame, 0); | |
695 | break; | |
696 | ||
697 | default: | |
e2e0b3e5 | 698 | internal_error (__FILE__, __LINE__, _("Unknown CFA rule.")); |
cfc14b3a MK |
699 | } |
700 | ||
05cbe71a | 701 | /* Initialize the register state. */ |
3e2c4033 AC |
702 | { |
703 | int regnum; | |
e4e9607c | 704 | |
3e2c4033 | 705 | for (regnum = 0; regnum < num_regs; regnum++) |
05cbe71a | 706 | dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum]); |
3e2c4033 AC |
707 | } |
708 | ||
709 | /* Go through the DWARF2 CFI generated table and save its register | |
79c4cb80 MK |
710 | location information in the cache. Note that we don't skip the |
711 | return address column; it's perfectly all right for it to | |
712 | correspond to a real register. If it doesn't correspond to a | |
713 | real register, or if we shouldn't treat it as such, | |
714 | DWARF2_REG_TO_REGNUM should be defined to return a number outside | |
715 | the range [0, NUM_REGS). */ | |
3e2c4033 AC |
716 | { |
717 | int column; /* CFI speak for "register number". */ | |
e4e9607c | 718 | |
3e2c4033 AC |
719 | for (column = 0; column < fs->regs.num_regs; column++) |
720 | { | |
3e2c4033 | 721 | /* Use the GDB register number as the destination index. */ |
79c4cb80 | 722 | int regnum = DWARF2_REG_TO_REGNUM (column); |
3e2c4033 AC |
723 | |
724 | /* If there's no corresponding GDB register, ignore it. */ | |
725 | if (regnum < 0 || regnum >= num_regs) | |
726 | continue; | |
727 | ||
728 | /* NOTE: cagney/2003-09-05: CFI should specify the disposition | |
e4e9607c MK |
729 | of all debug info registers. If it doesn't, complain (but |
730 | not too loudly). It turns out that GCC assumes that an | |
3e2c4033 AC |
731 | unspecified register implies "same value" when CFI (draft |
732 | 7) specifies nothing at all. Such a register could equally | |
733 | be interpreted as "undefined". Also note that this check | |
e4e9607c MK |
734 | isn't sufficient; it only checks that all registers in the |
735 | range [0 .. max column] are specified, and won't detect | |
3e2c4033 | 736 | problems when a debug info register falls outside of the |
e4e9607c | 737 | table. We need a way of iterating through all the valid |
3e2c4033 | 738 | DWARF2 register numbers. */ |
05cbe71a | 739 | if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED) |
f059bf6f AC |
740 | { |
741 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED) | |
e2e0b3e5 AC |
742 | complaint (&symfile_complaints, _("\ |
743 | incomplete CFI data; unspecified registers (e.g., %s) at 0x%s"), | |
f059bf6f AC |
744 | gdbarch_register_name (gdbarch, regnum), |
745 | paddr_nz (fs->pc)); | |
746 | } | |
35889917 MK |
747 | else |
748 | cache->reg[regnum] = fs->regs.reg[column]; | |
3e2c4033 AC |
749 | } |
750 | } | |
cfc14b3a | 751 | |
8d5a9abc MK |
752 | /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information |
753 | we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */ | |
35889917 MK |
754 | { |
755 | int regnum; | |
756 | ||
757 | for (regnum = 0; regnum < num_regs; regnum++) | |
758 | { | |
8d5a9abc MK |
759 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA |
760 | || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET) | |
35889917 | 761 | { |
05cbe71a MK |
762 | struct dwarf2_frame_state_reg *retaddr_reg = |
763 | &fs->regs.reg[fs->retaddr_column]; | |
764 | ||
d4f10bf2 MK |
765 | /* It seems rather bizarre to specify an "empty" column as |
766 | the return adress column. However, this is exactly | |
767 | what GCC does on some targets. It turns out that GCC | |
768 | assumes that the return address can be found in the | |
769 | register corresponding to the return address column. | |
8d5a9abc MK |
770 | Incidentally, that's how we should treat a return |
771 | address column specifying "same value" too. */ | |
d4f10bf2 | 772 | if (fs->retaddr_column < fs->regs.num_regs |
05cbe71a MK |
773 | && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED |
774 | && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE) | |
8d5a9abc MK |
775 | { |
776 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA) | |
777 | cache->reg[regnum] = *retaddr_reg; | |
778 | else | |
779 | cache->retaddr_reg = *retaddr_reg; | |
780 | } | |
35889917 MK |
781 | else |
782 | { | |
8d5a9abc MK |
783 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA) |
784 | { | |
785 | cache->reg[regnum].loc.reg = fs->retaddr_column; | |
786 | cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG; | |
787 | } | |
788 | else | |
789 | { | |
790 | cache->retaddr_reg.loc.reg = fs->retaddr_column; | |
791 | cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG; | |
792 | } | |
35889917 MK |
793 | } |
794 | } | |
795 | } | |
796 | } | |
cfc14b3a | 797 | |
0228dfb9 DJ |
798 | if (fs->retaddr_column < fs->regs.num_regs |
799 | && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED) | |
800 | cache->undefined_retaddr = 1; | |
801 | ||
cfc14b3a MK |
802 | do_cleanups (old_chain); |
803 | ||
804 | *this_cache = cache; | |
805 | return cache; | |
806 | } | |
807 | ||
808 | static void | |
809 | dwarf2_frame_this_id (struct frame_info *next_frame, void **this_cache, | |
810 | struct frame_id *this_id) | |
811 | { | |
812 | struct dwarf2_frame_cache *cache = | |
813 | dwarf2_frame_cache (next_frame, this_cache); | |
814 | ||
0228dfb9 DJ |
815 | if (cache->undefined_retaddr) |
816 | return; | |
817 | ||
cfc14b3a MK |
818 | (*this_id) = frame_id_build (cache->cfa, frame_func_unwind (next_frame)); |
819 | } | |
820 | ||
821 | static void | |
822 | dwarf2_frame_prev_register (struct frame_info *next_frame, void **this_cache, | |
823 | int regnum, int *optimizedp, | |
824 | enum lval_type *lvalp, CORE_ADDR *addrp, | |
c6826062 | 825 | int *realnump, gdb_byte *valuep) |
cfc14b3a | 826 | { |
05cbe71a | 827 | struct gdbarch *gdbarch = get_frame_arch (next_frame); |
cfc14b3a MK |
828 | struct dwarf2_frame_cache *cache = |
829 | dwarf2_frame_cache (next_frame, this_cache); | |
830 | ||
831 | switch (cache->reg[regnum].how) | |
832 | { | |
05cbe71a | 833 | case DWARF2_FRAME_REG_UNDEFINED: |
3e2c4033 | 834 | /* If CFI explicitly specified that the value isn't defined, |
e4e9607c | 835 | mark it as optimized away; the value isn't available. */ |
cfc14b3a MK |
836 | *optimizedp = 1; |
837 | *lvalp = not_lval; | |
838 | *addrp = 0; | |
839 | *realnump = -1; | |
35889917 | 840 | if (valuep) |
cfc14b3a MK |
841 | { |
842 | /* In some cases, for example %eflags on the i386, we have | |
843 | to provide a sane value, even though this register wasn't | |
844 | saved. Assume we can get it from NEXT_FRAME. */ | |
845 | frame_unwind_register (next_frame, regnum, valuep); | |
846 | } | |
847 | break; | |
848 | ||
05cbe71a | 849 | case DWARF2_FRAME_REG_SAVED_OFFSET: |
cfc14b3a MK |
850 | *optimizedp = 0; |
851 | *lvalp = lval_memory; | |
852 | *addrp = cache->cfa + cache->reg[regnum].loc.offset; | |
853 | *realnump = -1; | |
854 | if (valuep) | |
855 | { | |
856 | /* Read the value in from memory. */ | |
05cbe71a | 857 | read_memory (*addrp, valuep, register_size (gdbarch, regnum)); |
cfc14b3a MK |
858 | } |
859 | break; | |
860 | ||
05cbe71a | 861 | case DWARF2_FRAME_REG_SAVED_REG: |
00b25ff3 AC |
862 | *optimizedp = 0; |
863 | *lvalp = lval_register; | |
864 | *addrp = 0; | |
865 | *realnump = DWARF2_REG_TO_REGNUM (cache->reg[regnum].loc.reg); | |
866 | if (valuep) | |
867 | frame_unwind_register (next_frame, (*realnump), valuep); | |
cfc14b3a MK |
868 | break; |
869 | ||
05cbe71a | 870 | case DWARF2_FRAME_REG_SAVED_EXP: |
cfc14b3a MK |
871 | *optimizedp = 0; |
872 | *lvalp = lval_memory; | |
873 | *addrp = execute_stack_op (cache->reg[regnum].loc.exp, | |
874 | cache->reg[regnum].exp_len, | |
875 | next_frame, cache->cfa); | |
876 | *realnump = -1; | |
877 | if (valuep) | |
878 | { | |
879 | /* Read the value in from memory. */ | |
05cbe71a | 880 | read_memory (*addrp, valuep, register_size (gdbarch, regnum)); |
cfc14b3a MK |
881 | } |
882 | break; | |
883 | ||
05cbe71a | 884 | case DWARF2_FRAME_REG_UNSPECIFIED: |
3e2c4033 AC |
885 | /* GCC, in its infinite wisdom decided to not provide unwind |
886 | information for registers that are "same value". Since | |
887 | DWARF2 (3 draft 7) doesn't define such behavior, said | |
888 | registers are actually undefined (which is different to CFI | |
889 | "undefined"). Code above issues a complaint about this. | |
890 | Here just fudge the books, assume GCC, and that the value is | |
891 | more inner on the stack. */ | |
00b25ff3 AC |
892 | *optimizedp = 0; |
893 | *lvalp = lval_register; | |
894 | *addrp = 0; | |
895 | *realnump = regnum; | |
896 | if (valuep) | |
897 | frame_unwind_register (next_frame, (*realnump), valuep); | |
3e2c4033 AC |
898 | break; |
899 | ||
05cbe71a | 900 | case DWARF2_FRAME_REG_SAME_VALUE: |
00b25ff3 AC |
901 | *optimizedp = 0; |
902 | *lvalp = lval_register; | |
903 | *addrp = 0; | |
904 | *realnump = regnum; | |
905 | if (valuep) | |
906 | frame_unwind_register (next_frame, (*realnump), valuep); | |
cfc14b3a MK |
907 | break; |
908 | ||
05cbe71a | 909 | case DWARF2_FRAME_REG_CFA: |
35889917 MK |
910 | *optimizedp = 0; |
911 | *lvalp = not_lval; | |
912 | *addrp = 0; | |
913 | *realnump = -1; | |
914 | if (valuep) | |
915 | { | |
916 | /* Store the value. */ | |
917 | store_typed_address (valuep, builtin_type_void_data_ptr, cache->cfa); | |
918 | } | |
919 | break; | |
920 | ||
8d5a9abc MK |
921 | case DWARF2_FRAME_REG_RA_OFFSET: |
922 | *optimizedp = 0; | |
923 | *lvalp = not_lval; | |
924 | *addrp = 0; | |
925 | *realnump = -1; | |
926 | if (valuep) | |
927 | { | |
928 | CORE_ADDR pc = cache->reg[regnum].loc.offset; | |
929 | ||
930 | regnum = DWARF2_REG_TO_REGNUM (cache->retaddr_reg.loc.reg); | |
931 | pc += frame_unwind_register_unsigned (next_frame, regnum); | |
932 | store_typed_address (valuep, builtin_type_void_func_ptr, pc); | |
933 | } | |
934 | break; | |
935 | ||
cfc14b3a | 936 | default: |
e2e0b3e5 | 937 | internal_error (__FILE__, __LINE__, _("Unknown register rule.")); |
cfc14b3a MK |
938 | } |
939 | } | |
940 | ||
941 | static const struct frame_unwind dwarf2_frame_unwind = | |
942 | { | |
943 | NORMAL_FRAME, | |
944 | dwarf2_frame_this_id, | |
945 | dwarf2_frame_prev_register | |
946 | }; | |
947 | ||
3ed09a32 DJ |
948 | static const struct frame_unwind dwarf2_signal_frame_unwind = |
949 | { | |
950 | SIGTRAMP_FRAME, | |
951 | dwarf2_frame_this_id, | |
952 | dwarf2_frame_prev_register | |
953 | }; | |
954 | ||
cfc14b3a | 955 | const struct frame_unwind * |
336d1bba | 956 | dwarf2_frame_sniffer (struct frame_info *next_frame) |
cfc14b3a | 957 | { |
1ce5d6dd AC |
958 | /* Grab an address that is guarenteed to reside somewhere within the |
959 | function. frame_pc_unwind(), for a no-return next function, can | |
960 | end up returning something past the end of this function's body. */ | |
961 | CORE_ADDR block_addr = frame_unwind_address_in_block (next_frame); | |
3ed09a32 DJ |
962 | if (!dwarf2_frame_find_fde (&block_addr)) |
963 | return NULL; | |
964 | ||
965 | /* On some targets, signal trampolines may have unwind information. | |
966 | We need to recognize them so that we set the frame type | |
967 | correctly. */ | |
968 | ||
969 | if (dwarf2_frame_signal_frame_p (get_frame_arch (next_frame), | |
970 | next_frame)) | |
971 | return &dwarf2_signal_frame_unwind; | |
cfc14b3a | 972 | |
3ed09a32 | 973 | return &dwarf2_frame_unwind; |
cfc14b3a MK |
974 | } |
975 | \f | |
976 | ||
977 | /* There is no explicitly defined relationship between the CFA and the | |
978 | location of frame's local variables and arguments/parameters. | |
979 | Therefore, frame base methods on this page should probably only be | |
980 | used as a last resort, just to avoid printing total garbage as a | |
981 | response to the "info frame" command. */ | |
982 | ||
983 | static CORE_ADDR | |
984 | dwarf2_frame_base_address (struct frame_info *next_frame, void **this_cache) | |
985 | { | |
986 | struct dwarf2_frame_cache *cache = | |
987 | dwarf2_frame_cache (next_frame, this_cache); | |
988 | ||
989 | return cache->cfa; | |
990 | } | |
991 | ||
992 | static const struct frame_base dwarf2_frame_base = | |
993 | { | |
994 | &dwarf2_frame_unwind, | |
995 | dwarf2_frame_base_address, | |
996 | dwarf2_frame_base_address, | |
997 | dwarf2_frame_base_address | |
998 | }; | |
999 | ||
1000 | const struct frame_base * | |
336d1bba | 1001 | dwarf2_frame_base_sniffer (struct frame_info *next_frame) |
cfc14b3a | 1002 | { |
336d1bba | 1003 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
cfc14b3a MK |
1004 | if (dwarf2_frame_find_fde (&pc)) |
1005 | return &dwarf2_frame_base; | |
1006 | ||
1007 | return NULL; | |
1008 | } | |
1009 | \f | |
1010 | /* A minimal decoding of DWARF2 compilation units. We only decode | |
1011 | what's needed to get to the call frame information. */ | |
1012 | ||
1013 | struct comp_unit | |
1014 | { | |
1015 | /* Keep the bfd convenient. */ | |
1016 | bfd *abfd; | |
1017 | ||
1018 | struct objfile *objfile; | |
1019 | ||
1020 | /* Linked list of CIEs for this object. */ | |
1021 | struct dwarf2_cie *cie; | |
1022 | ||
cfc14b3a | 1023 | /* Pointer to the .debug_frame section loaded into memory. */ |
852483bc | 1024 | gdb_byte *dwarf_frame_buffer; |
cfc14b3a MK |
1025 | |
1026 | /* Length of the loaded .debug_frame section. */ | |
1027 | unsigned long dwarf_frame_size; | |
1028 | ||
1029 | /* Pointer to the .debug_frame section. */ | |
1030 | asection *dwarf_frame_section; | |
0912c7f2 MK |
1031 | |
1032 | /* Base for DW_EH_PE_datarel encodings. */ | |
1033 | bfd_vma dbase; | |
0fd85043 CV |
1034 | |
1035 | /* Base for DW_EH_PE_textrel encodings. */ | |
1036 | bfd_vma tbase; | |
cfc14b3a MK |
1037 | }; |
1038 | ||
8f22cb90 | 1039 | const struct objfile_data *dwarf2_frame_objfile_data; |
0d0e1a63 | 1040 | |
cfc14b3a | 1041 | static unsigned int |
852483bc | 1042 | read_1_byte (bfd *abfd, gdb_byte *buf) |
cfc14b3a | 1043 | { |
852483bc | 1044 | return bfd_get_8 (abfd, buf); |
cfc14b3a MK |
1045 | } |
1046 | ||
1047 | static unsigned int | |
852483bc | 1048 | read_4_bytes (bfd *abfd, gdb_byte *buf) |
cfc14b3a | 1049 | { |
852483bc | 1050 | return bfd_get_32 (abfd, buf); |
cfc14b3a MK |
1051 | } |
1052 | ||
1053 | static ULONGEST | |
852483bc | 1054 | read_8_bytes (bfd *abfd, gdb_byte *buf) |
cfc14b3a | 1055 | { |
852483bc | 1056 | return bfd_get_64 (abfd, buf); |
cfc14b3a MK |
1057 | } |
1058 | ||
1059 | static ULONGEST | |
852483bc | 1060 | read_unsigned_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr) |
cfc14b3a MK |
1061 | { |
1062 | ULONGEST result; | |
1063 | unsigned int num_read; | |
1064 | int shift; | |
852483bc | 1065 | gdb_byte byte; |
cfc14b3a MK |
1066 | |
1067 | result = 0; | |
1068 | shift = 0; | |
1069 | num_read = 0; | |
1070 | ||
1071 | do | |
1072 | { | |
1073 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); | |
1074 | buf++; | |
1075 | num_read++; | |
1076 | result |= ((byte & 0x7f) << shift); | |
1077 | shift += 7; | |
1078 | } | |
1079 | while (byte & 0x80); | |
1080 | ||
1081 | *bytes_read_ptr = num_read; | |
1082 | ||
1083 | return result; | |
1084 | } | |
1085 | ||
1086 | static LONGEST | |
852483bc | 1087 | read_signed_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr) |
cfc14b3a MK |
1088 | { |
1089 | LONGEST result; | |
1090 | int shift; | |
1091 | unsigned int num_read; | |
852483bc | 1092 | gdb_byte byte; |
cfc14b3a MK |
1093 | |
1094 | result = 0; | |
1095 | shift = 0; | |
1096 | num_read = 0; | |
1097 | ||
1098 | do | |
1099 | { | |
1100 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); | |
1101 | buf++; | |
1102 | num_read++; | |
1103 | result |= ((byte & 0x7f) << shift); | |
1104 | shift += 7; | |
1105 | } | |
1106 | while (byte & 0x80); | |
1107 | ||
77e0b926 DJ |
1108 | if (shift < 8 * sizeof (result) && (byte & 0x40)) |
1109 | result |= -(((LONGEST)1) << shift); | |
cfc14b3a MK |
1110 | |
1111 | *bytes_read_ptr = num_read; | |
1112 | ||
1113 | return result; | |
1114 | } | |
1115 | ||
1116 | static ULONGEST | |
852483bc | 1117 | read_initial_length (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr) |
cfc14b3a MK |
1118 | { |
1119 | LONGEST result; | |
1120 | ||
852483bc | 1121 | result = bfd_get_32 (abfd, buf); |
cfc14b3a MK |
1122 | if (result == 0xffffffff) |
1123 | { | |
852483bc | 1124 | result = bfd_get_64 (abfd, buf + 4); |
cfc14b3a MK |
1125 | *bytes_read_ptr = 12; |
1126 | } | |
1127 | else | |
1128 | *bytes_read_ptr = 4; | |
1129 | ||
1130 | return result; | |
1131 | } | |
1132 | \f | |
1133 | ||
1134 | /* Pointer encoding helper functions. */ | |
1135 | ||
1136 | /* GCC supports exception handling based on DWARF2 CFI. However, for | |
1137 | technical reasons, it encodes addresses in its FDE's in a different | |
1138 | way. Several "pointer encodings" are supported. The encoding | |
1139 | that's used for a particular FDE is determined by the 'R' | |
1140 | augmentation in the associated CIE. The argument of this | |
1141 | augmentation is a single byte. | |
1142 | ||
1143 | The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a | |
1144 | LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether | |
1145 | the address is signed or unsigned. Bits 4, 5 and 6 encode how the | |
1146 | address should be interpreted (absolute, relative to the current | |
1147 | position in the FDE, ...). Bit 7, indicates that the address | |
1148 | should be dereferenced. */ | |
1149 | ||
852483bc | 1150 | static gdb_byte |
cfc14b3a MK |
1151 | encoding_for_size (unsigned int size) |
1152 | { | |
1153 | switch (size) | |
1154 | { | |
1155 | case 2: | |
1156 | return DW_EH_PE_udata2; | |
1157 | case 4: | |
1158 | return DW_EH_PE_udata4; | |
1159 | case 8: | |
1160 | return DW_EH_PE_udata8; | |
1161 | default: | |
e2e0b3e5 | 1162 | internal_error (__FILE__, __LINE__, _("Unsupported address size")); |
cfc14b3a MK |
1163 | } |
1164 | } | |
1165 | ||
1166 | static unsigned int | |
852483bc | 1167 | size_of_encoded_value (gdb_byte encoding) |
cfc14b3a MK |
1168 | { |
1169 | if (encoding == DW_EH_PE_omit) | |
1170 | return 0; | |
1171 | ||
1172 | switch (encoding & 0x07) | |
1173 | { | |
1174 | case DW_EH_PE_absptr: | |
1175 | return TYPE_LENGTH (builtin_type_void_data_ptr); | |
1176 | case DW_EH_PE_udata2: | |
1177 | return 2; | |
1178 | case DW_EH_PE_udata4: | |
1179 | return 4; | |
1180 | case DW_EH_PE_udata8: | |
1181 | return 8; | |
1182 | default: | |
e2e0b3e5 | 1183 | internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding")); |
cfc14b3a MK |
1184 | } |
1185 | } | |
1186 | ||
1187 | static CORE_ADDR | |
852483bc MK |
1188 | read_encoded_value (struct comp_unit *unit, gdb_byte encoding, |
1189 | gdb_byte *buf, unsigned int *bytes_read_ptr) | |
cfc14b3a | 1190 | { |
68f6cf99 MK |
1191 | int ptr_len = size_of_encoded_value (DW_EH_PE_absptr); |
1192 | ptrdiff_t offset; | |
cfc14b3a MK |
1193 | CORE_ADDR base; |
1194 | ||
1195 | /* GCC currently doesn't generate DW_EH_PE_indirect encodings for | |
1196 | FDE's. */ | |
1197 | if (encoding & DW_EH_PE_indirect) | |
1198 | internal_error (__FILE__, __LINE__, | |
e2e0b3e5 | 1199 | _("Unsupported encoding: DW_EH_PE_indirect")); |
cfc14b3a | 1200 | |
68f6cf99 MK |
1201 | *bytes_read_ptr = 0; |
1202 | ||
cfc14b3a MK |
1203 | switch (encoding & 0x70) |
1204 | { | |
1205 | case DW_EH_PE_absptr: | |
1206 | base = 0; | |
1207 | break; | |
1208 | case DW_EH_PE_pcrel: | |
1209 | base = bfd_get_section_vma (unit->bfd, unit->dwarf_frame_section); | |
852483bc | 1210 | base += (buf - unit->dwarf_frame_buffer); |
cfc14b3a | 1211 | break; |
0912c7f2 MK |
1212 | case DW_EH_PE_datarel: |
1213 | base = unit->dbase; | |
1214 | break; | |
0fd85043 CV |
1215 | case DW_EH_PE_textrel: |
1216 | base = unit->tbase; | |
1217 | break; | |
03ac2a74 MK |
1218 | case DW_EH_PE_funcrel: |
1219 | /* FIXME: kettenis/20040501: For now just pretend | |
1220 | DW_EH_PE_funcrel is equivalent to DW_EH_PE_absptr. For | |
1221 | reading the initial location of an FDE it should be treated | |
1222 | as such, and currently that's the only place where this code | |
1223 | is used. */ | |
1224 | base = 0; | |
1225 | break; | |
68f6cf99 MK |
1226 | case DW_EH_PE_aligned: |
1227 | base = 0; | |
852483bc | 1228 | offset = buf - unit->dwarf_frame_buffer; |
68f6cf99 MK |
1229 | if ((offset % ptr_len) != 0) |
1230 | { | |
1231 | *bytes_read_ptr = ptr_len - (offset % ptr_len); | |
1232 | buf += *bytes_read_ptr; | |
1233 | } | |
1234 | break; | |
cfc14b3a | 1235 | default: |
e2e0b3e5 | 1236 | internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding")); |
cfc14b3a MK |
1237 | } |
1238 | ||
b04de778 | 1239 | if ((encoding & 0x07) == 0x00) |
68f6cf99 | 1240 | encoding |= encoding_for_size (ptr_len); |
cfc14b3a MK |
1241 | |
1242 | switch (encoding & 0x0f) | |
1243 | { | |
a81b10ae MK |
1244 | case DW_EH_PE_uleb128: |
1245 | { | |
1246 | ULONGEST value; | |
852483bc | 1247 | gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7; |
a7289609 | 1248 | *bytes_read_ptr += read_uleb128 (buf, end_buf, &value) - buf; |
a81b10ae MK |
1249 | return base + value; |
1250 | } | |
cfc14b3a | 1251 | case DW_EH_PE_udata2: |
68f6cf99 | 1252 | *bytes_read_ptr += 2; |
cfc14b3a MK |
1253 | return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf)); |
1254 | case DW_EH_PE_udata4: | |
68f6cf99 | 1255 | *bytes_read_ptr += 4; |
cfc14b3a MK |
1256 | return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf)); |
1257 | case DW_EH_PE_udata8: | |
68f6cf99 | 1258 | *bytes_read_ptr += 8; |
cfc14b3a | 1259 | return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf)); |
a81b10ae MK |
1260 | case DW_EH_PE_sleb128: |
1261 | { | |
1262 | LONGEST value; | |
852483bc | 1263 | gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7; |
a7289609 | 1264 | *bytes_read_ptr += read_sleb128 (buf, end_buf, &value) - buf; |
a81b10ae MK |
1265 | return base + value; |
1266 | } | |
cfc14b3a | 1267 | case DW_EH_PE_sdata2: |
68f6cf99 | 1268 | *bytes_read_ptr += 2; |
cfc14b3a MK |
1269 | return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf)); |
1270 | case DW_EH_PE_sdata4: | |
68f6cf99 | 1271 | *bytes_read_ptr += 4; |
cfc14b3a MK |
1272 | return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf)); |
1273 | case DW_EH_PE_sdata8: | |
68f6cf99 | 1274 | *bytes_read_ptr += 8; |
cfc14b3a MK |
1275 | return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf)); |
1276 | default: | |
e2e0b3e5 | 1277 | internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding")); |
cfc14b3a MK |
1278 | } |
1279 | } | |
1280 | \f | |
1281 | ||
1282 | /* GCC uses a single CIE for all FDEs in a .debug_frame section. | |
1283 | That's why we use a simple linked list here. */ | |
1284 | ||
1285 | static struct dwarf2_cie * | |
1286 | find_cie (struct comp_unit *unit, ULONGEST cie_pointer) | |
1287 | { | |
1288 | struct dwarf2_cie *cie = unit->cie; | |
1289 | ||
1290 | while (cie) | |
1291 | { | |
1292 | if (cie->cie_pointer == cie_pointer) | |
1293 | return cie; | |
1294 | ||
1295 | cie = cie->next; | |
1296 | } | |
1297 | ||
1298 | return NULL; | |
1299 | } | |
1300 | ||
1301 | static void | |
1302 | add_cie (struct comp_unit *unit, struct dwarf2_cie *cie) | |
1303 | { | |
1304 | cie->next = unit->cie; | |
1305 | unit->cie = cie; | |
1306 | } | |
1307 | ||
1308 | /* Find the FDE for *PC. Return a pointer to the FDE, and store the | |
1309 | inital location associated with it into *PC. */ | |
1310 | ||
1311 | static struct dwarf2_fde * | |
1312 | dwarf2_frame_find_fde (CORE_ADDR *pc) | |
1313 | { | |
1314 | struct objfile *objfile; | |
1315 | ||
1316 | ALL_OBJFILES (objfile) | |
1317 | { | |
1318 | struct dwarf2_fde *fde; | |
1319 | CORE_ADDR offset; | |
1320 | ||
8f22cb90 | 1321 | fde = objfile_data (objfile, dwarf2_frame_objfile_data); |
4ae9ee8e DJ |
1322 | if (fde == NULL) |
1323 | continue; | |
1324 | ||
1325 | gdb_assert (objfile->section_offsets); | |
1326 | offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile)); | |
1327 | ||
cfc14b3a MK |
1328 | while (fde) |
1329 | { | |
1330 | if (*pc >= fde->initial_location + offset | |
1331 | && *pc < fde->initial_location + offset + fde->address_range) | |
1332 | { | |
1333 | *pc = fde->initial_location + offset; | |
1334 | return fde; | |
1335 | } | |
1336 | ||
1337 | fde = fde->next; | |
1338 | } | |
1339 | } | |
1340 | ||
1341 | return NULL; | |
1342 | } | |
1343 | ||
1344 | static void | |
1345 | add_fde (struct comp_unit *unit, struct dwarf2_fde *fde) | |
1346 | { | |
8f22cb90 MK |
1347 | fde->next = objfile_data (unit->objfile, dwarf2_frame_objfile_data); |
1348 | set_objfile_data (unit->objfile, dwarf2_frame_objfile_data, fde); | |
cfc14b3a MK |
1349 | } |
1350 | ||
1351 | #ifdef CC_HAS_LONG_LONG | |
1352 | #define DW64_CIE_ID 0xffffffffffffffffULL | |
1353 | #else | |
1354 | #define DW64_CIE_ID ~0 | |
1355 | #endif | |
1356 | ||
852483bc MK |
1357 | static gdb_byte *decode_frame_entry (struct comp_unit *unit, gdb_byte *start, |
1358 | int eh_frame_p); | |
cfc14b3a | 1359 | |
6896c0c7 RH |
1360 | /* Decode the next CIE or FDE. Return NULL if invalid input, otherwise |
1361 | the next byte to be processed. */ | |
852483bc MK |
1362 | static gdb_byte * |
1363 | decode_frame_entry_1 (struct comp_unit *unit, gdb_byte *start, int eh_frame_p) | |
cfc14b3a | 1364 | { |
852483bc | 1365 | gdb_byte *buf, *end; |
cfc14b3a MK |
1366 | LONGEST length; |
1367 | unsigned int bytes_read; | |
6896c0c7 RH |
1368 | int dwarf64_p; |
1369 | ULONGEST cie_id; | |
cfc14b3a | 1370 | ULONGEST cie_pointer; |
cfc14b3a | 1371 | |
6896c0c7 | 1372 | buf = start; |
cfc14b3a MK |
1373 | length = read_initial_length (unit->abfd, buf, &bytes_read); |
1374 | buf += bytes_read; | |
1375 | end = buf + length; | |
1376 | ||
6896c0c7 RH |
1377 | /* Are we still within the section? */ |
1378 | if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size) | |
1379 | return NULL; | |
1380 | ||
cfc14b3a MK |
1381 | if (length == 0) |
1382 | return end; | |
1383 | ||
6896c0c7 RH |
1384 | /* Distinguish between 32 and 64-bit encoded frame info. */ |
1385 | dwarf64_p = (bytes_read == 12); | |
cfc14b3a | 1386 | |
6896c0c7 | 1387 | /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */ |
cfc14b3a MK |
1388 | if (eh_frame_p) |
1389 | cie_id = 0; | |
1390 | else if (dwarf64_p) | |
1391 | cie_id = DW64_CIE_ID; | |
6896c0c7 RH |
1392 | else |
1393 | cie_id = DW_CIE_ID; | |
cfc14b3a MK |
1394 | |
1395 | if (dwarf64_p) | |
1396 | { | |
1397 | cie_pointer = read_8_bytes (unit->abfd, buf); | |
1398 | buf += 8; | |
1399 | } | |
1400 | else | |
1401 | { | |
1402 | cie_pointer = read_4_bytes (unit->abfd, buf); | |
1403 | buf += 4; | |
1404 | } | |
1405 | ||
1406 | if (cie_pointer == cie_id) | |
1407 | { | |
1408 | /* This is a CIE. */ | |
1409 | struct dwarf2_cie *cie; | |
1410 | char *augmentation; | |
28ba0b33 | 1411 | unsigned int cie_version; |
cfc14b3a MK |
1412 | |
1413 | /* Record the offset into the .debug_frame section of this CIE. */ | |
1414 | cie_pointer = start - unit->dwarf_frame_buffer; | |
1415 | ||
1416 | /* Check whether we've already read it. */ | |
1417 | if (find_cie (unit, cie_pointer)) | |
1418 | return end; | |
1419 | ||
1420 | cie = (struct dwarf2_cie *) | |
8b92e4d5 | 1421 | obstack_alloc (&unit->objfile->objfile_obstack, |
cfc14b3a MK |
1422 | sizeof (struct dwarf2_cie)); |
1423 | cie->initial_instructions = NULL; | |
1424 | cie->cie_pointer = cie_pointer; | |
1425 | ||
1426 | /* The encoding for FDE's in a normal .debug_frame section | |
32b05c07 MK |
1427 | depends on the target address size. */ |
1428 | cie->encoding = DW_EH_PE_absptr; | |
cfc14b3a MK |
1429 | |
1430 | /* Check version number. */ | |
28ba0b33 PB |
1431 | cie_version = read_1_byte (unit->abfd, buf); |
1432 | if (cie_version != 1 && cie_version != 3) | |
6896c0c7 | 1433 | return NULL; |
cfc14b3a MK |
1434 | buf += 1; |
1435 | ||
1436 | /* Interpret the interesting bits of the augmentation. */ | |
852483bc MK |
1437 | augmentation = (char *) buf; |
1438 | buf += (strlen (augmentation) + 1); | |
cfc14b3a MK |
1439 | |
1440 | /* The GCC 2.x "eh" augmentation has a pointer immediately | |
1441 | following the augmentation string, so it must be handled | |
1442 | first. */ | |
1443 | if (augmentation[0] == 'e' && augmentation[1] == 'h') | |
1444 | { | |
1445 | /* Skip. */ | |
1446 | buf += TYPE_LENGTH (builtin_type_void_data_ptr); | |
1447 | augmentation += 2; | |
1448 | } | |
1449 | ||
1450 | cie->code_alignment_factor = | |
1451 | read_unsigned_leb128 (unit->abfd, buf, &bytes_read); | |
1452 | buf += bytes_read; | |
1453 | ||
1454 | cie->data_alignment_factor = | |
1455 | read_signed_leb128 (unit->abfd, buf, &bytes_read); | |
1456 | buf += bytes_read; | |
1457 | ||
28ba0b33 PB |
1458 | if (cie_version == 1) |
1459 | { | |
1460 | cie->return_address_register = read_1_byte (unit->abfd, buf); | |
1461 | bytes_read = 1; | |
1462 | } | |
1463 | else | |
1464 | cie->return_address_register = read_unsigned_leb128 (unit->abfd, buf, | |
1465 | &bytes_read); | |
1466 | buf += bytes_read; | |
cfc14b3a | 1467 | |
7131cb6e RH |
1468 | cie->saw_z_augmentation = (*augmentation == 'z'); |
1469 | if (cie->saw_z_augmentation) | |
cfc14b3a MK |
1470 | { |
1471 | ULONGEST length; | |
1472 | ||
1473 | length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read); | |
1474 | buf += bytes_read; | |
6896c0c7 RH |
1475 | if (buf > end) |
1476 | return NULL; | |
cfc14b3a MK |
1477 | cie->initial_instructions = buf + length; |
1478 | augmentation++; | |
1479 | } | |
1480 | ||
1481 | while (*augmentation) | |
1482 | { | |
1483 | /* "L" indicates a byte showing how the LSDA pointer is encoded. */ | |
1484 | if (*augmentation == 'L') | |
1485 | { | |
1486 | /* Skip. */ | |
1487 | buf++; | |
1488 | augmentation++; | |
1489 | } | |
1490 | ||
1491 | /* "R" indicates a byte indicating how FDE addresses are encoded. */ | |
1492 | else if (*augmentation == 'R') | |
1493 | { | |
1494 | cie->encoding = *buf++; | |
1495 | augmentation++; | |
1496 | } | |
1497 | ||
1498 | /* "P" indicates a personality routine in the CIE augmentation. */ | |
1499 | else if (*augmentation == 'P') | |
1500 | { | |
1234d960 | 1501 | /* Skip. Avoid indirection since we throw away the result. */ |
852483bc | 1502 | gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect; |
f724bf08 MK |
1503 | read_encoded_value (unit, encoding, buf, &bytes_read); |
1504 | buf += bytes_read; | |
cfc14b3a MK |
1505 | augmentation++; |
1506 | } | |
1507 | ||
1508 | /* Otherwise we have an unknown augmentation. | |
1509 | Bail out unless we saw a 'z' prefix. */ | |
1510 | else | |
1511 | { | |
1512 | if (cie->initial_instructions == NULL) | |
1513 | return end; | |
1514 | ||
1515 | /* Skip unknown augmentations. */ | |
1516 | buf = cie->initial_instructions; | |
1517 | break; | |
1518 | } | |
1519 | } | |
1520 | ||
1521 | cie->initial_instructions = buf; | |
1522 | cie->end = end; | |
1523 | ||
1524 | add_cie (unit, cie); | |
1525 | } | |
1526 | else | |
1527 | { | |
1528 | /* This is a FDE. */ | |
1529 | struct dwarf2_fde *fde; | |
1530 | ||
6896c0c7 RH |
1531 | /* In an .eh_frame section, the CIE pointer is the delta between the |
1532 | address within the FDE where the CIE pointer is stored and the | |
1533 | address of the CIE. Convert it to an offset into the .eh_frame | |
1534 | section. */ | |
cfc14b3a MK |
1535 | if (eh_frame_p) |
1536 | { | |
cfc14b3a MK |
1537 | cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer; |
1538 | cie_pointer -= (dwarf64_p ? 8 : 4); | |
1539 | } | |
1540 | ||
6896c0c7 RH |
1541 | /* In either case, validate the result is still within the section. */ |
1542 | if (cie_pointer >= unit->dwarf_frame_size) | |
1543 | return NULL; | |
1544 | ||
cfc14b3a | 1545 | fde = (struct dwarf2_fde *) |
8b92e4d5 | 1546 | obstack_alloc (&unit->objfile->objfile_obstack, |
cfc14b3a MK |
1547 | sizeof (struct dwarf2_fde)); |
1548 | fde->cie = find_cie (unit, cie_pointer); | |
1549 | if (fde->cie == NULL) | |
1550 | { | |
1551 | decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer, | |
1552 | eh_frame_p); | |
1553 | fde->cie = find_cie (unit, cie_pointer); | |
1554 | } | |
1555 | ||
1556 | gdb_assert (fde->cie != NULL); | |
1557 | ||
1558 | fde->initial_location = | |
1559 | read_encoded_value (unit, fde->cie->encoding, buf, &bytes_read); | |
1560 | buf += bytes_read; | |
1561 | ||
1562 | fde->address_range = | |
1563 | read_encoded_value (unit, fde->cie->encoding & 0x0f, buf, &bytes_read); | |
1564 | buf += bytes_read; | |
1565 | ||
7131cb6e RH |
1566 | /* A 'z' augmentation in the CIE implies the presence of an |
1567 | augmentation field in the FDE as well. The only thing known | |
1568 | to be in here at present is the LSDA entry for EH. So we | |
1569 | can skip the whole thing. */ | |
1570 | if (fde->cie->saw_z_augmentation) | |
1571 | { | |
1572 | ULONGEST length; | |
1573 | ||
1574 | length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read); | |
1575 | buf += bytes_read + length; | |
6896c0c7 RH |
1576 | if (buf > end) |
1577 | return NULL; | |
7131cb6e RH |
1578 | } |
1579 | ||
cfc14b3a MK |
1580 | fde->instructions = buf; |
1581 | fde->end = end; | |
1582 | ||
1583 | add_fde (unit, fde); | |
1584 | } | |
1585 | ||
1586 | return end; | |
1587 | } | |
6896c0c7 RH |
1588 | |
1589 | /* Read a CIE or FDE in BUF and decode it. */ | |
852483bc MK |
1590 | static gdb_byte * |
1591 | decode_frame_entry (struct comp_unit *unit, gdb_byte *start, int eh_frame_p) | |
6896c0c7 RH |
1592 | { |
1593 | enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE; | |
852483bc | 1594 | gdb_byte *ret; |
6896c0c7 RH |
1595 | const char *msg; |
1596 | ptrdiff_t start_offset; | |
1597 | ||
1598 | while (1) | |
1599 | { | |
1600 | ret = decode_frame_entry_1 (unit, start, eh_frame_p); | |
1601 | if (ret != NULL) | |
1602 | break; | |
1603 | ||
1604 | /* We have corrupt input data of some form. */ | |
1605 | ||
1606 | /* ??? Try, weakly, to work around compiler/assembler/linker bugs | |
1607 | and mismatches wrt padding and alignment of debug sections. */ | |
1608 | /* Note that there is no requirement in the standard for any | |
1609 | alignment at all in the frame unwind sections. Testing for | |
1610 | alignment before trying to interpret data would be incorrect. | |
1611 | ||
1612 | However, GCC traditionally arranged for frame sections to be | |
1613 | sized such that the FDE length and CIE fields happen to be | |
1614 | aligned (in theory, for performance). This, unfortunately, | |
1615 | was done with .align directives, which had the side effect of | |
1616 | forcing the section to be aligned by the linker. | |
1617 | ||
1618 | This becomes a problem when you have some other producer that | |
1619 | creates frame sections that are not as strictly aligned. That | |
1620 | produces a hole in the frame info that gets filled by the | |
1621 | linker with zeros. | |
1622 | ||
1623 | The GCC behaviour is arguably a bug, but it's effectively now | |
1624 | part of the ABI, so we're now stuck with it, at least at the | |
1625 | object file level. A smart linker may decide, in the process | |
1626 | of compressing duplicate CIE information, that it can rewrite | |
1627 | the entire output section without this extra padding. */ | |
1628 | ||
1629 | start_offset = start - unit->dwarf_frame_buffer; | |
1630 | if (workaround < ALIGN4 && (start_offset & 3) != 0) | |
1631 | { | |
1632 | start += 4 - (start_offset & 3); | |
1633 | workaround = ALIGN4; | |
1634 | continue; | |
1635 | } | |
1636 | if (workaround < ALIGN8 && (start_offset & 7) != 0) | |
1637 | { | |
1638 | start += 8 - (start_offset & 7); | |
1639 | workaround = ALIGN8; | |
1640 | continue; | |
1641 | } | |
1642 | ||
1643 | /* Nothing left to try. Arrange to return as if we've consumed | |
1644 | the entire input section. Hopefully we'll get valid info from | |
1645 | the other of .debug_frame/.eh_frame. */ | |
1646 | workaround = FAIL; | |
1647 | ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size; | |
1648 | break; | |
1649 | } | |
1650 | ||
1651 | switch (workaround) | |
1652 | { | |
1653 | case NONE: | |
1654 | break; | |
1655 | ||
1656 | case ALIGN4: | |
1657 | complaint (&symfile_complaints, | |
e2e0b3e5 | 1658 | _("Corrupt data in %s:%s; align 4 workaround apparently succeeded"), |
6896c0c7 RH |
1659 | unit->dwarf_frame_section->owner->filename, |
1660 | unit->dwarf_frame_section->name); | |
1661 | break; | |
1662 | ||
1663 | case ALIGN8: | |
1664 | complaint (&symfile_complaints, | |
e2e0b3e5 | 1665 | _("Corrupt data in %s:%s; align 8 workaround apparently succeeded"), |
6896c0c7 RH |
1666 | unit->dwarf_frame_section->owner->filename, |
1667 | unit->dwarf_frame_section->name); | |
1668 | break; | |
1669 | ||
1670 | default: | |
1671 | complaint (&symfile_complaints, | |
e2e0b3e5 | 1672 | _("Corrupt data in %s:%s"), |
6896c0c7 RH |
1673 | unit->dwarf_frame_section->owner->filename, |
1674 | unit->dwarf_frame_section->name); | |
1675 | break; | |
1676 | } | |
1677 | ||
1678 | return ret; | |
1679 | } | |
cfc14b3a MK |
1680 | \f |
1681 | ||
1682 | /* FIXME: kettenis/20030504: This still needs to be integrated with | |
1683 | dwarf2read.c in a better way. */ | |
1684 | ||
1685 | /* Imported from dwarf2read.c. */ | |
cfc14b3a | 1686 | extern asection *dwarf_frame_section; |
cfc14b3a MK |
1687 | extern asection *dwarf_eh_frame_section; |
1688 | ||
1689 | /* Imported from dwarf2read.c. */ | |
188dd5d6 | 1690 | extern char *dwarf2_read_section (struct objfile *objfile, asection *sectp); |
cfc14b3a MK |
1691 | |
1692 | void | |
1693 | dwarf2_build_frame_info (struct objfile *objfile) | |
1694 | { | |
1695 | struct comp_unit unit; | |
852483bc | 1696 | gdb_byte *frame_ptr; |
cfc14b3a MK |
1697 | |
1698 | /* Build a minimal decoding of the DWARF2 compilation unit. */ | |
1699 | unit.abfd = objfile->obfd; | |
1700 | unit.objfile = objfile; | |
0912c7f2 | 1701 | unit.dbase = 0; |
0fd85043 | 1702 | unit.tbase = 0; |
cfc14b3a MK |
1703 | |
1704 | /* First add the information from the .eh_frame section. That way, | |
1705 | the FDEs from that section are searched last. */ | |
188dd5d6 | 1706 | if (dwarf_eh_frame_section) |
cfc14b3a | 1707 | { |
0fd85043 | 1708 | asection *got, *txt; |
0912c7f2 | 1709 | |
cfc14b3a MK |
1710 | unit.cie = NULL; |
1711 | unit.dwarf_frame_buffer = dwarf2_read_section (objfile, | |
cfc14b3a MK |
1712 | dwarf_eh_frame_section); |
1713 | ||
2c500098 | 1714 | unit.dwarf_frame_size = bfd_get_section_size (dwarf_eh_frame_section); |
cfc14b3a MK |
1715 | unit.dwarf_frame_section = dwarf_eh_frame_section; |
1716 | ||
0912c7f2 | 1717 | /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base |
37b517aa MK |
1718 | that is used for the i386/amd64 target, which currently is |
1719 | the only target in GCC that supports/uses the | |
1720 | DW_EH_PE_datarel encoding. */ | |
0912c7f2 MK |
1721 | got = bfd_get_section_by_name (unit.abfd, ".got"); |
1722 | if (got) | |
1723 | unit.dbase = got->vma; | |
1724 | ||
22c7ba1a MK |
1725 | /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64 |
1726 | so far. */ | |
0fd85043 CV |
1727 | txt = bfd_get_section_by_name (unit.abfd, ".text"); |
1728 | if (txt) | |
1729 | unit.tbase = txt->vma; | |
1730 | ||
cfc14b3a MK |
1731 | frame_ptr = unit.dwarf_frame_buffer; |
1732 | while (frame_ptr < unit.dwarf_frame_buffer + unit.dwarf_frame_size) | |
1733 | frame_ptr = decode_frame_entry (&unit, frame_ptr, 1); | |
1734 | } | |
1735 | ||
188dd5d6 | 1736 | if (dwarf_frame_section) |
cfc14b3a MK |
1737 | { |
1738 | unit.cie = NULL; | |
1739 | unit.dwarf_frame_buffer = dwarf2_read_section (objfile, | |
cfc14b3a | 1740 | dwarf_frame_section); |
2c500098 | 1741 | unit.dwarf_frame_size = bfd_get_section_size (dwarf_frame_section); |
cfc14b3a MK |
1742 | unit.dwarf_frame_section = dwarf_frame_section; |
1743 | ||
1744 | frame_ptr = unit.dwarf_frame_buffer; | |
1745 | while (frame_ptr < unit.dwarf_frame_buffer + unit.dwarf_frame_size) | |
1746 | frame_ptr = decode_frame_entry (&unit, frame_ptr, 0); | |
1747 | } | |
1748 | } | |
0d0e1a63 MK |
1749 | |
1750 | /* Provide a prototype to silence -Wmissing-prototypes. */ | |
1751 | void _initialize_dwarf2_frame (void); | |
1752 | ||
1753 | void | |
1754 | _initialize_dwarf2_frame (void) | |
1755 | { | |
030f20e1 | 1756 | dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init); |
8f22cb90 | 1757 | dwarf2_frame_objfile_data = register_objfile_data (); |
0d0e1a63 | 1758 | } |