Commit | Line | Data |
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cfc14b3a MK |
1 | /* Frame unwinder for frames with DWARF Call Frame Information. |
2 | ||
3 | Copyright 2003 Free Software Foundation, Inc. | |
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. */ | |
63 | unsigned char *initial_instructions; | |
64 | unsigned char *end; | |
65 | ||
66 | /* Encoding of addresses. */ | |
67 | unsigned char encoding; | |
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. */ | |
89 | unsigned char *instructions; | |
90 | unsigned char *end; | |
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 | ||
3e2c4033 AC |
100 | enum dwarf2_reg_rule |
101 | { | |
e4e9607c | 102 | /* Make certain that 0 maps onto the correct enum value; the |
3e2c4033 AC |
103 | corresponding structure is being initialized using memset zero. |
104 | This indicates that CFI didn't provide any information at all | |
3e74aeed | 105 | about a register, leaving how to obtain its value totally |
3e2c4033 AC |
106 | unspecified. */ |
107 | REG_UNSPECIFIED = 0, | |
35889917 | 108 | |
3e2c4033 | 109 | /* The term "undefined" comes from the DWARF2 CFI spec which this |
e4e9607c MK |
110 | code is moddeling; it indicates that the register's value is |
111 | "undefined". GCC uses the less formal term "unsaved". Its | |
112 | definition is a combination of REG_UNDEFINED and REG_UNSPECIFIED. | |
113 | The failure to differentiate the two helps explain a few problems | |
114 | with the CFI generated by GCC. */ | |
3e2c4033 AC |
115 | REG_UNDEFINED, |
116 | REG_SAVED_OFFSET, | |
117 | REG_SAVED_REG, | |
118 | REG_SAVED_EXP, | |
35889917 MK |
119 | REG_SAME_VALUE, |
120 | ||
121 | /* These aren't defined by the DWARF2 CFI specification, but are | |
122 | used internally by GDB. */ | |
123 | REG_RA, /* Return Address. */ | |
124 | REG_CFA /* Call Frame Address. */ | |
3e2c4033 AC |
125 | }; |
126 | ||
cfc14b3a MK |
127 | struct dwarf2_frame_state |
128 | { | |
129 | /* Each register save state can be described in terms of a CFA slot, | |
130 | another register, or a location expression. */ | |
131 | struct dwarf2_frame_state_reg_info | |
132 | { | |
133 | struct dwarf2_frame_state_reg | |
134 | { | |
135 | union { | |
136 | LONGEST offset; | |
137 | ULONGEST reg; | |
138 | unsigned char *exp; | |
139 | } loc; | |
140 | ULONGEST exp_len; | |
3e2c4033 | 141 | enum dwarf2_reg_rule how; |
cfc14b3a MK |
142 | } *reg; |
143 | int num_regs; | |
144 | ||
145 | /* Used to implement DW_CFA_remember_state. */ | |
146 | struct dwarf2_frame_state_reg_info *prev; | |
147 | } regs; | |
148 | ||
149 | LONGEST cfa_offset; | |
150 | ULONGEST cfa_reg; | |
151 | unsigned char *cfa_exp; | |
152 | enum { | |
153 | CFA_UNSET, | |
154 | CFA_REG_OFFSET, | |
155 | CFA_EXP | |
156 | } cfa_how; | |
157 | ||
158 | /* The PC described by the current frame state. */ | |
159 | CORE_ADDR pc; | |
160 | ||
161 | /* Initial register set from the CIE. | |
162 | Used to implement DW_CFA_restore. */ | |
163 | struct dwarf2_frame_state_reg_info initial; | |
164 | ||
165 | /* The information we care about from the CIE. */ | |
166 | LONGEST data_align; | |
167 | ULONGEST code_align; | |
168 | ULONGEST retaddr_column; | |
169 | }; | |
170 | ||
171 | /* Store the length the expression for the CFA in the `cfa_reg' field, | |
172 | which is unused in that case. */ | |
173 | #define cfa_exp_len cfa_reg | |
174 | ||
175 | /* Assert that the register set RS is large enough to store NUM_REGS | |
176 | columns. If necessary, enlarge the register set. */ | |
177 | ||
178 | static void | |
179 | dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs, | |
180 | int num_regs) | |
181 | { | |
182 | size_t size = sizeof (struct dwarf2_frame_state_reg); | |
183 | ||
184 | if (num_regs <= rs->num_regs) | |
185 | return; | |
186 | ||
187 | rs->reg = (struct dwarf2_frame_state_reg *) | |
188 | xrealloc (rs->reg, num_regs * size); | |
189 | ||
190 | /* Initialize newly allocated registers. */ | |
2473a4a9 | 191 | memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size); |
cfc14b3a MK |
192 | rs->num_regs = num_regs; |
193 | } | |
194 | ||
195 | /* Copy the register columns in register set RS into newly allocated | |
196 | memory and return a pointer to this newly created copy. */ | |
197 | ||
198 | static struct dwarf2_frame_state_reg * | |
199 | dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs) | |
200 | { | |
201 | size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg_info); | |
202 | struct dwarf2_frame_state_reg *reg; | |
203 | ||
204 | reg = (struct dwarf2_frame_state_reg *) xmalloc (size); | |
205 | memcpy (reg, rs->reg, size); | |
206 | ||
207 | return reg; | |
208 | } | |
209 | ||
210 | /* Release the memory allocated to register set RS. */ | |
211 | ||
212 | static void | |
213 | dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs) | |
214 | { | |
215 | if (rs) | |
216 | { | |
217 | dwarf2_frame_state_free_regs (rs->prev); | |
218 | ||
219 | xfree (rs->reg); | |
220 | xfree (rs); | |
221 | } | |
222 | } | |
223 | ||
224 | /* Release the memory allocated to the frame state FS. */ | |
225 | ||
226 | static void | |
227 | dwarf2_frame_state_free (void *p) | |
228 | { | |
229 | struct dwarf2_frame_state *fs = p; | |
230 | ||
231 | dwarf2_frame_state_free_regs (fs->initial.prev); | |
232 | dwarf2_frame_state_free_regs (fs->regs.prev); | |
233 | xfree (fs->initial.reg); | |
234 | xfree (fs->regs.reg); | |
235 | xfree (fs); | |
236 | } | |
237 | \f | |
238 | ||
239 | /* Helper functions for execute_stack_op. */ | |
240 | ||
241 | static CORE_ADDR | |
242 | read_reg (void *baton, int reg) | |
243 | { | |
244 | struct frame_info *next_frame = (struct frame_info *) baton; | |
245 | int regnum; | |
246 | char *buf; | |
247 | ||
248 | regnum = DWARF2_REG_TO_REGNUM (reg); | |
249 | ||
250 | buf = (char *) alloca (register_size (current_gdbarch, regnum)); | |
251 | frame_unwind_register (next_frame, regnum, buf); | |
252 | return extract_typed_address (buf, builtin_type_void_data_ptr); | |
253 | } | |
254 | ||
255 | static void | |
256 | read_mem (void *baton, char *buf, CORE_ADDR addr, size_t len) | |
257 | { | |
258 | read_memory (addr, buf, len); | |
259 | } | |
260 | ||
261 | static void | |
262 | no_get_frame_base (void *baton, unsigned char **start, size_t *length) | |
263 | { | |
264 | internal_error (__FILE__, __LINE__, | |
265 | "Support for DW_OP_fbreg is unimplemented"); | |
266 | } | |
267 | ||
268 | static CORE_ADDR | |
269 | no_get_tls_address (void *baton, CORE_ADDR offset) | |
270 | { | |
271 | internal_error (__FILE__, __LINE__, | |
272 | "Support for DW_OP_GNU_push_tls_address is unimplemented"); | |
273 | } | |
274 | ||
275 | static CORE_ADDR | |
276 | execute_stack_op (unsigned char *exp, ULONGEST len, | |
277 | struct frame_info *next_frame, CORE_ADDR initial) | |
278 | { | |
279 | struct dwarf_expr_context *ctx; | |
280 | CORE_ADDR result; | |
281 | ||
282 | ctx = new_dwarf_expr_context (); | |
283 | ctx->baton = next_frame; | |
284 | ctx->read_reg = read_reg; | |
285 | ctx->read_mem = read_mem; | |
286 | ctx->get_frame_base = no_get_frame_base; | |
287 | ctx->get_tls_address = no_get_tls_address; | |
288 | ||
289 | dwarf_expr_push (ctx, initial); | |
290 | dwarf_expr_eval (ctx, exp, len); | |
291 | result = dwarf_expr_fetch (ctx, 0); | |
292 | ||
293 | if (ctx->in_reg) | |
294 | result = read_reg (next_frame, result); | |
295 | ||
296 | free_dwarf_expr_context (ctx); | |
297 | ||
298 | return result; | |
299 | } | |
300 | \f | |
301 | ||
302 | static void | |
303 | execute_cfa_program (unsigned char *insn_ptr, unsigned char *insn_end, | |
304 | struct frame_info *next_frame, | |
305 | struct dwarf2_frame_state *fs) | |
306 | { | |
307 | CORE_ADDR pc = frame_pc_unwind (next_frame); | |
308 | int bytes_read; | |
309 | ||
310 | while (insn_ptr < insn_end && fs->pc <= pc) | |
311 | { | |
312 | unsigned char insn = *insn_ptr++; | |
313 | ULONGEST utmp, reg; | |
314 | LONGEST offset; | |
315 | ||
316 | if ((insn & 0xc0) == DW_CFA_advance_loc) | |
317 | fs->pc += (insn & 0x3f) * fs->code_align; | |
318 | else if ((insn & 0xc0) == DW_CFA_offset) | |
319 | { | |
320 | reg = insn & 0x3f; | |
321 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
322 | offset = utmp * fs->data_align; | |
323 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
324 | fs->regs.reg[reg].how = REG_SAVED_OFFSET; | |
325 | fs->regs.reg[reg].loc.offset = offset; | |
326 | } | |
327 | else if ((insn & 0xc0) == DW_CFA_restore) | |
328 | { | |
329 | gdb_assert (fs->initial.reg); | |
330 | reg = insn & 0x3f; | |
331 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
332 | fs->regs.reg[reg] = fs->initial.reg[reg]; | |
333 | } | |
334 | else | |
335 | { | |
336 | switch (insn) | |
337 | { | |
338 | case DW_CFA_set_loc: | |
339 | fs->pc = dwarf2_read_address (insn_ptr, insn_end, &bytes_read); | |
340 | insn_ptr += bytes_read; | |
341 | break; | |
342 | ||
343 | case DW_CFA_advance_loc1: | |
344 | utmp = extract_unsigned_integer (insn_ptr, 1); | |
345 | fs->pc += utmp * fs->code_align; | |
346 | insn_ptr++; | |
347 | break; | |
348 | case DW_CFA_advance_loc2: | |
349 | utmp = extract_unsigned_integer (insn_ptr, 2); | |
350 | fs->pc += utmp * fs->code_align; | |
351 | insn_ptr += 2; | |
352 | break; | |
353 | case DW_CFA_advance_loc4: | |
354 | utmp = extract_unsigned_integer (insn_ptr, 4); | |
355 | fs->pc += utmp * fs->code_align; | |
356 | insn_ptr += 4; | |
357 | break; | |
358 | ||
359 | case DW_CFA_offset_extended: | |
360 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
361 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
362 | offset = utmp * fs->data_align; | |
363 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
364 | fs->regs.reg[reg].how = REG_SAVED_OFFSET; | |
365 | fs->regs.reg[reg].loc.offset = offset; | |
366 | break; | |
367 | ||
368 | case DW_CFA_restore_extended: | |
369 | gdb_assert (fs->initial.reg); | |
370 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
371 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
372 | fs->regs.reg[reg] = fs->initial.reg[reg]; | |
373 | break; | |
374 | ||
375 | case DW_CFA_undefined: | |
376 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
377 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
3e2c4033 | 378 | fs->regs.reg[reg].how = REG_UNDEFINED; |
cfc14b3a MK |
379 | break; |
380 | ||
381 | case DW_CFA_same_value: | |
382 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
383 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
3e2c4033 | 384 | fs->regs.reg[reg].how = REG_SAME_VALUE; |
cfc14b3a MK |
385 | break; |
386 | ||
387 | case DW_CFA_register: | |
388 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
389 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
390 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
cbdfc7c0 | 391 | fs->regs.reg[reg].how = REG_SAVED_REG; |
cfc14b3a MK |
392 | fs->regs.reg[reg].loc.reg = utmp; |
393 | break; | |
394 | ||
395 | case DW_CFA_remember_state: | |
396 | { | |
397 | struct dwarf2_frame_state_reg_info *new_rs; | |
398 | ||
399 | new_rs = XMALLOC (struct dwarf2_frame_state_reg_info); | |
400 | *new_rs = fs->regs; | |
401 | fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs); | |
402 | fs->regs.prev = new_rs; | |
403 | } | |
404 | break; | |
405 | ||
406 | case DW_CFA_restore_state: | |
407 | { | |
408 | struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev; | |
409 | ||
410 | gdb_assert (old_rs); | |
411 | ||
412 | xfree (fs->regs.reg); | |
413 | fs->regs = *old_rs; | |
414 | xfree (old_rs); | |
415 | } | |
416 | break; | |
417 | ||
418 | case DW_CFA_def_cfa: | |
419 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); | |
420 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
421 | fs->cfa_offset = utmp; | |
422 | fs->cfa_how = CFA_REG_OFFSET; | |
423 | break; | |
424 | ||
425 | case DW_CFA_def_cfa_register: | |
426 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); | |
427 | fs->cfa_how = CFA_REG_OFFSET; | |
428 | break; | |
429 | ||
430 | case DW_CFA_def_cfa_offset: | |
431 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_offset); | |
432 | /* cfa_how deliberately not set. */ | |
433 | break; | |
434 | ||
a8504492 MK |
435 | case DW_CFA_nop: |
436 | break; | |
437 | ||
cfc14b3a MK |
438 | case DW_CFA_def_cfa_expression: |
439 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_exp_len); | |
440 | fs->cfa_exp = insn_ptr; | |
441 | fs->cfa_how = CFA_EXP; | |
442 | insn_ptr += fs->cfa_exp_len; | |
443 | break; | |
444 | ||
445 | case DW_CFA_expression: | |
446 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
447 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
448 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
449 | fs->regs.reg[reg].loc.exp = insn_ptr; | |
450 | fs->regs.reg[reg].exp_len = utmp; | |
451 | fs->regs.reg[reg].how = REG_SAVED_EXP; | |
452 | insn_ptr += utmp; | |
453 | break; | |
454 | ||
a8504492 MK |
455 | case DW_CFA_offset_extended_sf: |
456 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
457 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); | |
458 | offset += fs->data_align; | |
459 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
460 | fs->regs.reg[reg].how = REG_SAVED_OFFSET; | |
461 | fs->regs.reg[reg].loc.offset = offset; | |
462 | break; | |
463 | ||
464 | case DW_CFA_def_cfa_sf: | |
465 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); | |
466 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); | |
467 | fs->cfa_offset = offset * fs->data_align; | |
468 | fs->cfa_how = CFA_REG_OFFSET; | |
469 | break; | |
470 | ||
471 | case DW_CFA_def_cfa_offset_sf: | |
472 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); | |
473 | fs->cfa_offset = offset * fs->data_align; | |
474 | /* cfa_how deliberately not set. */ | |
cfc14b3a MK |
475 | break; |
476 | ||
477 | case DW_CFA_GNU_args_size: | |
478 | /* Ignored. */ | |
479 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
480 | break; | |
481 | ||
482 | default: | |
483 | internal_error (__FILE__, __LINE__, "Unknown CFI encountered."); | |
484 | } | |
485 | } | |
486 | } | |
487 | ||
488 | /* Don't allow remember/restore between CIE and FDE programs. */ | |
489 | dwarf2_frame_state_free_regs (fs->regs.prev); | |
490 | fs->regs.prev = NULL; | |
491 | } | |
492 | ||
493 | struct dwarf2_frame_cache | |
494 | { | |
495 | /* DWARF Call Frame Address. */ | |
496 | CORE_ADDR cfa; | |
497 | ||
498 | /* Saved registers, indexed by GDB register number, not by DWARF | |
499 | register number. */ | |
500 | struct dwarf2_frame_state_reg *reg; | |
501 | }; | |
502 | ||
b9362cc7 | 503 | static struct dwarf2_frame_cache * |
cfc14b3a MK |
504 | dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache) |
505 | { | |
506 | struct cleanup *old_chain; | |
3e2c4033 | 507 | const int num_regs = NUM_REGS + NUM_PSEUDO_REGS; |
cfc14b3a MK |
508 | struct dwarf2_frame_cache *cache; |
509 | struct dwarf2_frame_state *fs; | |
510 | struct dwarf2_fde *fde; | |
cfc14b3a MK |
511 | |
512 | if (*this_cache) | |
513 | return *this_cache; | |
514 | ||
515 | /* Allocate a new cache. */ | |
516 | cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache); | |
517 | cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg); | |
518 | ||
519 | /* Allocate and initialize the frame state. */ | |
520 | fs = XMALLOC (struct dwarf2_frame_state); | |
521 | memset (fs, 0, sizeof (struct dwarf2_frame_state)); | |
522 | old_chain = make_cleanup (dwarf2_frame_state_free, fs); | |
523 | ||
524 | /* Unwind the PC. | |
525 | ||
526 | Note that if NEXT_FRAME is never supposed to return (i.e. a call | |
527 | to abort), the compiler might optimize away the instruction at | |
528 | NEXT_FRAME's return address. As a result the return address will | |
529 | point at some random instruction, and the CFI for that | |
e4e9607c | 530 | instruction is probably worthless to us. GCC's unwinder solves |
cfc14b3a MK |
531 | this problem by substracting 1 from the return address to get an |
532 | address in the middle of a presumed call instruction (or the | |
533 | instruction in the associated delay slot). This should only be | |
534 | done for "normal" frames and not for resume-type frames (signal | |
e4e9607c MK |
535 | handlers, sentinel frames, dummy frames). The function |
536 | frame_unwind_address_in_block does just this. It's not clear how | |
537 | reliable the method is though; there is the potential for the | |
538 | register state pre-call being different to that on return. */ | |
1ce5d6dd | 539 | fs->pc = frame_unwind_address_in_block (next_frame); |
cfc14b3a MK |
540 | |
541 | /* Find the correct FDE. */ | |
542 | fde = dwarf2_frame_find_fde (&fs->pc); | |
543 | gdb_assert (fde != NULL); | |
544 | ||
545 | /* Extract any interesting information from the CIE. */ | |
546 | fs->data_align = fde->cie->data_alignment_factor; | |
547 | fs->code_align = fde->cie->code_alignment_factor; | |
548 | fs->retaddr_column = fde->cie->return_address_register; | |
549 | ||
550 | /* First decode all the insns in the CIE. */ | |
551 | execute_cfa_program (fde->cie->initial_instructions, | |
552 | fde->cie->end, next_frame, fs); | |
553 | ||
554 | /* Save the initialized register set. */ | |
555 | fs->initial = fs->regs; | |
556 | fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs); | |
557 | ||
558 | /* Then decode the insns in the FDE up to our target PC. */ | |
559 | execute_cfa_program (fde->instructions, fde->end, next_frame, fs); | |
560 | ||
561 | /* Caclulate the CFA. */ | |
562 | switch (fs->cfa_how) | |
563 | { | |
564 | case CFA_REG_OFFSET: | |
565 | cache->cfa = read_reg (next_frame, fs->cfa_reg); | |
566 | cache->cfa += fs->cfa_offset; | |
567 | break; | |
568 | ||
569 | case CFA_EXP: | |
570 | cache->cfa = | |
571 | execute_stack_op (fs->cfa_exp, fs->cfa_exp_len, next_frame, 0); | |
572 | break; | |
573 | ||
574 | default: | |
575 | internal_error (__FILE__, __LINE__, "Unknown CFA rule."); | |
576 | } | |
577 | ||
35889917 MK |
578 | /* Initialize the register rules. If we have a register that acts |
579 | as a program counter, mark it as a destination for the return | |
580 | address. If we have a register that serves as the stack pointer, | |
581 | arrange for it to be filled with the call frame address (CFA). | |
582 | The other registers are marked as unspecified. | |
583 | ||
584 | We copy the return address to the program counter, since many | |
585 | parts in GDB assume that it is possible to get the return address | |
586 | by unwind the program counter register. However, on ISA's with a | |
587 | dedicated return address register, the CFI usually only contains | |
588 | information to unwind that return address register. | |
589 | ||
590 | The reason we're treating the stack pointer special here is | |
591 | because in many cases GCC doesn't emit CFI for the stack pointer | |
592 | and implicitly assumes that it is equal to the CFA. This makes | |
593 | some sense since the DWARF specification (version 3, draft 8, | |
594 | p. 102) says that: | |
595 | ||
596 | "Typically, the CFA is defined to be the value of the stack | |
597 | pointer at the call site in the previous frame (which may be | |
598 | different from its value on entry to the current frame)." | |
599 | ||
600 | However, this isn't true for all platforms supported by GCC | |
601 | (e.g. IBM S/390 and zSeries). For those targets we should | |
602 | override the defaults given here. */ | |
3e2c4033 AC |
603 | { |
604 | int regnum; | |
e4e9607c | 605 | |
3e2c4033 | 606 | for (regnum = 0; regnum < num_regs; regnum++) |
35889917 MK |
607 | { |
608 | if (regnum == PC_REGNUM) | |
609 | cache->reg[regnum].how = REG_RA; | |
610 | else if (regnum == SP_REGNUM) | |
611 | cache->reg[regnum].how = REG_CFA; | |
612 | else | |
613 | cache->reg[regnum].how = REG_UNSPECIFIED; | |
614 | } | |
3e2c4033 AC |
615 | } |
616 | ||
617 | /* Go through the DWARF2 CFI generated table and save its register | |
79c4cb80 MK |
618 | location information in the cache. Note that we don't skip the |
619 | return address column; it's perfectly all right for it to | |
620 | correspond to a real register. If it doesn't correspond to a | |
621 | real register, or if we shouldn't treat it as such, | |
622 | DWARF2_REG_TO_REGNUM should be defined to return a number outside | |
623 | the range [0, NUM_REGS). */ | |
3e2c4033 AC |
624 | { |
625 | int column; /* CFI speak for "register number". */ | |
e4e9607c | 626 | |
3e2c4033 AC |
627 | for (column = 0; column < fs->regs.num_regs; column++) |
628 | { | |
3e2c4033 | 629 | /* Use the GDB register number as the destination index. */ |
79c4cb80 | 630 | int regnum = DWARF2_REG_TO_REGNUM (column); |
3e2c4033 AC |
631 | |
632 | /* If there's no corresponding GDB register, ignore it. */ | |
633 | if (regnum < 0 || regnum >= num_regs) | |
634 | continue; | |
635 | ||
636 | /* NOTE: cagney/2003-09-05: CFI should specify the disposition | |
e4e9607c MK |
637 | of all debug info registers. If it doesn't, complain (but |
638 | not too loudly). It turns out that GCC assumes that an | |
3e2c4033 AC |
639 | unspecified register implies "same value" when CFI (draft |
640 | 7) specifies nothing at all. Such a register could equally | |
641 | be interpreted as "undefined". Also note that this check | |
e4e9607c MK |
642 | isn't sufficient; it only checks that all registers in the |
643 | range [0 .. max column] are specified, and won't detect | |
3e2c4033 | 644 | problems when a debug info register falls outside of the |
e4e9607c | 645 | table. We need a way of iterating through all the valid |
3e2c4033 AC |
646 | DWARF2 register numbers. */ |
647 | if (fs->regs.reg[column].how == REG_UNSPECIFIED) | |
648 | complaint (&symfile_complaints, | |
649 | "Incomplete CFI data; unspecified registers at 0x%s", | |
650 | paddr (fs->pc)); | |
35889917 MK |
651 | else |
652 | cache->reg[regnum] = fs->regs.reg[column]; | |
3e2c4033 AC |
653 | } |
654 | } | |
cfc14b3a | 655 | |
35889917 MK |
656 | /* Eliminate any REG_RA rules. */ |
657 | { | |
658 | int regnum; | |
659 | ||
660 | for (regnum = 0; regnum < num_regs; regnum++) | |
661 | { | |
662 | if (cache->reg[regnum].how == REG_RA) | |
663 | { | |
d4f10bf2 MK |
664 | /* It seems rather bizarre to specify an "empty" column as |
665 | the return adress column. However, this is exactly | |
666 | what GCC does on some targets. It turns out that GCC | |
667 | assumes that the return address can be found in the | |
668 | register corresponding to the return address column. | |
669 | Incidentally, that's how should treat a return address | |
670 | column specifying "same value" too. */ | |
671 | if (fs->retaddr_column < fs->regs.num_regs | |
672 | && fs->regs.reg[fs->retaddr_column].how != REG_UNSPECIFIED | |
673 | && fs->regs.reg[fs->retaddr_column].how != REG_SAME_VALUE) | |
35889917 MK |
674 | cache->reg[regnum] = fs->regs.reg[fs->retaddr_column]; |
675 | else | |
676 | { | |
35889917 MK |
677 | cache->reg[regnum].loc.reg = fs->retaddr_column; |
678 | cache->reg[regnum].how = REG_SAVED_REG; | |
679 | } | |
680 | } | |
681 | } | |
682 | } | |
cfc14b3a MK |
683 | |
684 | do_cleanups (old_chain); | |
685 | ||
686 | *this_cache = cache; | |
687 | return cache; | |
688 | } | |
689 | ||
690 | static void | |
691 | dwarf2_frame_this_id (struct frame_info *next_frame, void **this_cache, | |
692 | struct frame_id *this_id) | |
693 | { | |
694 | struct dwarf2_frame_cache *cache = | |
695 | dwarf2_frame_cache (next_frame, this_cache); | |
696 | ||
697 | (*this_id) = frame_id_build (cache->cfa, frame_func_unwind (next_frame)); | |
698 | } | |
699 | ||
700 | static void | |
701 | dwarf2_frame_prev_register (struct frame_info *next_frame, void **this_cache, | |
702 | int regnum, int *optimizedp, | |
703 | enum lval_type *lvalp, CORE_ADDR *addrp, | |
704 | int *realnump, void *valuep) | |
705 | { | |
706 | struct dwarf2_frame_cache *cache = | |
707 | dwarf2_frame_cache (next_frame, this_cache); | |
708 | ||
709 | switch (cache->reg[regnum].how) | |
710 | { | |
3e2c4033 AC |
711 | case REG_UNDEFINED: |
712 | /* If CFI explicitly specified that the value isn't defined, | |
e4e9607c | 713 | mark it as optimized away; the value isn't available. */ |
cfc14b3a MK |
714 | *optimizedp = 1; |
715 | *lvalp = not_lval; | |
716 | *addrp = 0; | |
717 | *realnump = -1; | |
35889917 | 718 | if (valuep) |
cfc14b3a MK |
719 | { |
720 | /* In some cases, for example %eflags on the i386, we have | |
721 | to provide a sane value, even though this register wasn't | |
722 | saved. Assume we can get it from NEXT_FRAME. */ | |
723 | frame_unwind_register (next_frame, regnum, valuep); | |
724 | } | |
725 | break; | |
726 | ||
727 | case REG_SAVED_OFFSET: | |
728 | *optimizedp = 0; | |
729 | *lvalp = lval_memory; | |
730 | *addrp = cache->cfa + cache->reg[regnum].loc.offset; | |
731 | *realnump = -1; | |
732 | if (valuep) | |
733 | { | |
734 | /* Read the value in from memory. */ | |
735 | read_memory (*addrp, valuep, | |
736 | register_size (current_gdbarch, regnum)); | |
737 | } | |
738 | break; | |
739 | ||
740 | case REG_SAVED_REG: | |
741 | regnum = DWARF2_REG_TO_REGNUM (cache->reg[regnum].loc.reg); | |
742 | frame_register_unwind (next_frame, regnum, | |
743 | optimizedp, lvalp, addrp, realnump, valuep); | |
744 | break; | |
745 | ||
746 | case REG_SAVED_EXP: | |
747 | *optimizedp = 0; | |
748 | *lvalp = lval_memory; | |
749 | *addrp = execute_stack_op (cache->reg[regnum].loc.exp, | |
750 | cache->reg[regnum].exp_len, | |
751 | next_frame, cache->cfa); | |
752 | *realnump = -1; | |
753 | if (valuep) | |
754 | { | |
755 | /* Read the value in from memory. */ | |
756 | read_memory (*addrp, valuep, | |
757 | register_size (current_gdbarch, regnum)); | |
758 | } | |
759 | break; | |
760 | ||
3e2c4033 AC |
761 | case REG_UNSPECIFIED: |
762 | /* GCC, in its infinite wisdom decided to not provide unwind | |
763 | information for registers that are "same value". Since | |
764 | DWARF2 (3 draft 7) doesn't define such behavior, said | |
765 | registers are actually undefined (which is different to CFI | |
766 | "undefined"). Code above issues a complaint about this. | |
767 | Here just fudge the books, assume GCC, and that the value is | |
768 | more inner on the stack. */ | |
35889917 MK |
769 | frame_register_unwind (next_frame, regnum, |
770 | optimizedp, lvalp, addrp, realnump, valuep); | |
3e2c4033 AC |
771 | break; |
772 | ||
773 | case REG_SAME_VALUE: | |
cfc14b3a MK |
774 | frame_register_unwind (next_frame, regnum, |
775 | optimizedp, lvalp, addrp, realnump, valuep); | |
776 | break; | |
777 | ||
35889917 MK |
778 | case REG_CFA: |
779 | *optimizedp = 0; | |
780 | *lvalp = not_lval; | |
781 | *addrp = 0; | |
782 | *realnump = -1; | |
783 | if (valuep) | |
784 | { | |
785 | /* Store the value. */ | |
786 | store_typed_address (valuep, builtin_type_void_data_ptr, cache->cfa); | |
787 | } | |
788 | break; | |
789 | ||
cfc14b3a MK |
790 | default: |
791 | internal_error (__FILE__, __LINE__, "Unknown register rule."); | |
792 | } | |
793 | } | |
794 | ||
795 | static const struct frame_unwind dwarf2_frame_unwind = | |
796 | { | |
797 | NORMAL_FRAME, | |
798 | dwarf2_frame_this_id, | |
799 | dwarf2_frame_prev_register | |
800 | }; | |
801 | ||
802 | const struct frame_unwind * | |
336d1bba | 803 | dwarf2_frame_sniffer (struct frame_info *next_frame) |
cfc14b3a | 804 | { |
1ce5d6dd AC |
805 | /* Grab an address that is guarenteed to reside somewhere within the |
806 | function. frame_pc_unwind(), for a no-return next function, can | |
807 | end up returning something past the end of this function's body. */ | |
808 | CORE_ADDR block_addr = frame_unwind_address_in_block (next_frame); | |
809 | if (dwarf2_frame_find_fde (&block_addr)) | |
cfc14b3a MK |
810 | return &dwarf2_frame_unwind; |
811 | ||
812 | return NULL; | |
813 | } | |
814 | \f | |
815 | ||
816 | /* There is no explicitly defined relationship between the CFA and the | |
817 | location of frame's local variables and arguments/parameters. | |
818 | Therefore, frame base methods on this page should probably only be | |
819 | used as a last resort, just to avoid printing total garbage as a | |
820 | response to the "info frame" command. */ | |
821 | ||
822 | static CORE_ADDR | |
823 | dwarf2_frame_base_address (struct frame_info *next_frame, void **this_cache) | |
824 | { | |
825 | struct dwarf2_frame_cache *cache = | |
826 | dwarf2_frame_cache (next_frame, this_cache); | |
827 | ||
828 | return cache->cfa; | |
829 | } | |
830 | ||
831 | static const struct frame_base dwarf2_frame_base = | |
832 | { | |
833 | &dwarf2_frame_unwind, | |
834 | dwarf2_frame_base_address, | |
835 | dwarf2_frame_base_address, | |
836 | dwarf2_frame_base_address | |
837 | }; | |
838 | ||
839 | const struct frame_base * | |
336d1bba | 840 | dwarf2_frame_base_sniffer (struct frame_info *next_frame) |
cfc14b3a | 841 | { |
336d1bba | 842 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
cfc14b3a MK |
843 | if (dwarf2_frame_find_fde (&pc)) |
844 | return &dwarf2_frame_base; | |
845 | ||
846 | return NULL; | |
847 | } | |
848 | \f | |
849 | /* A minimal decoding of DWARF2 compilation units. We only decode | |
850 | what's needed to get to the call frame information. */ | |
851 | ||
852 | struct comp_unit | |
853 | { | |
854 | /* Keep the bfd convenient. */ | |
855 | bfd *abfd; | |
856 | ||
857 | struct objfile *objfile; | |
858 | ||
859 | /* Linked list of CIEs for this object. */ | |
860 | struct dwarf2_cie *cie; | |
861 | ||
862 | /* Address size for this unit - from unit header. */ | |
863 | unsigned char addr_size; | |
864 | ||
865 | /* Pointer to the .debug_frame section loaded into memory. */ | |
866 | char *dwarf_frame_buffer; | |
867 | ||
868 | /* Length of the loaded .debug_frame section. */ | |
869 | unsigned long dwarf_frame_size; | |
870 | ||
871 | /* Pointer to the .debug_frame section. */ | |
872 | asection *dwarf_frame_section; | |
0912c7f2 MK |
873 | |
874 | /* Base for DW_EH_PE_datarel encodings. */ | |
875 | bfd_vma dbase; | |
0fd85043 CV |
876 | |
877 | /* Base for DW_EH_PE_textrel encodings. */ | |
878 | bfd_vma tbase; | |
cfc14b3a MK |
879 | }; |
880 | ||
0d0e1a63 MK |
881 | const struct objfile_data *dwarf2_frame_data; |
882 | ||
cfc14b3a MK |
883 | static unsigned int |
884 | read_1_byte (bfd *bfd, char *buf) | |
885 | { | |
886 | return bfd_get_8 (abfd, (bfd_byte *) buf); | |
887 | } | |
888 | ||
889 | static unsigned int | |
890 | read_4_bytes (bfd *abfd, char *buf) | |
891 | { | |
892 | return bfd_get_32 (abfd, (bfd_byte *) buf); | |
893 | } | |
894 | ||
895 | static ULONGEST | |
896 | read_8_bytes (bfd *abfd, char *buf) | |
897 | { | |
898 | return bfd_get_64 (abfd, (bfd_byte *) buf); | |
899 | } | |
900 | ||
901 | static ULONGEST | |
902 | read_unsigned_leb128 (bfd *abfd, char *buf, unsigned int *bytes_read_ptr) | |
903 | { | |
904 | ULONGEST result; | |
905 | unsigned int num_read; | |
906 | int shift; | |
907 | unsigned char byte; | |
908 | ||
909 | result = 0; | |
910 | shift = 0; | |
911 | num_read = 0; | |
912 | ||
913 | do | |
914 | { | |
915 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); | |
916 | buf++; | |
917 | num_read++; | |
918 | result |= ((byte & 0x7f) << shift); | |
919 | shift += 7; | |
920 | } | |
921 | while (byte & 0x80); | |
922 | ||
923 | *bytes_read_ptr = num_read; | |
924 | ||
925 | return result; | |
926 | } | |
927 | ||
928 | static LONGEST | |
929 | read_signed_leb128 (bfd *abfd, char *buf, unsigned int *bytes_read_ptr) | |
930 | { | |
931 | LONGEST result; | |
932 | int shift; | |
933 | unsigned int num_read; | |
934 | unsigned char byte; | |
935 | ||
936 | result = 0; | |
937 | shift = 0; | |
938 | num_read = 0; | |
939 | ||
940 | do | |
941 | { | |
942 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); | |
943 | buf++; | |
944 | num_read++; | |
945 | result |= ((byte & 0x7f) << shift); | |
946 | shift += 7; | |
947 | } | |
948 | while (byte & 0x80); | |
949 | ||
950 | if ((shift < 32) && (byte & 0x40)) | |
951 | result |= -(1 << shift); | |
952 | ||
953 | *bytes_read_ptr = num_read; | |
954 | ||
955 | return result; | |
956 | } | |
957 | ||
958 | static ULONGEST | |
959 | read_initial_length (bfd *abfd, char *buf, unsigned int *bytes_read_ptr) | |
960 | { | |
961 | LONGEST result; | |
962 | ||
963 | result = bfd_get_32 (abfd, (bfd_byte *) buf); | |
964 | if (result == 0xffffffff) | |
965 | { | |
966 | result = bfd_get_64 (abfd, (bfd_byte *) buf + 4); | |
967 | *bytes_read_ptr = 12; | |
968 | } | |
969 | else | |
970 | *bytes_read_ptr = 4; | |
971 | ||
972 | return result; | |
973 | } | |
974 | \f | |
975 | ||
976 | /* Pointer encoding helper functions. */ | |
977 | ||
978 | /* GCC supports exception handling based on DWARF2 CFI. However, for | |
979 | technical reasons, it encodes addresses in its FDE's in a different | |
980 | way. Several "pointer encodings" are supported. The encoding | |
981 | that's used for a particular FDE is determined by the 'R' | |
982 | augmentation in the associated CIE. The argument of this | |
983 | augmentation is a single byte. | |
984 | ||
985 | The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a | |
986 | LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether | |
987 | the address is signed or unsigned. Bits 4, 5 and 6 encode how the | |
988 | address should be interpreted (absolute, relative to the current | |
989 | position in the FDE, ...). Bit 7, indicates that the address | |
990 | should be dereferenced. */ | |
991 | ||
992 | static unsigned char | |
993 | encoding_for_size (unsigned int size) | |
994 | { | |
995 | switch (size) | |
996 | { | |
997 | case 2: | |
998 | return DW_EH_PE_udata2; | |
999 | case 4: | |
1000 | return DW_EH_PE_udata4; | |
1001 | case 8: | |
1002 | return DW_EH_PE_udata8; | |
1003 | default: | |
1004 | internal_error (__FILE__, __LINE__, "Unsupported address size"); | |
1005 | } | |
1006 | } | |
1007 | ||
1008 | static unsigned int | |
1009 | size_of_encoded_value (unsigned char encoding) | |
1010 | { | |
1011 | if (encoding == DW_EH_PE_omit) | |
1012 | return 0; | |
1013 | ||
1014 | switch (encoding & 0x07) | |
1015 | { | |
1016 | case DW_EH_PE_absptr: | |
1017 | return TYPE_LENGTH (builtin_type_void_data_ptr); | |
1018 | case DW_EH_PE_udata2: | |
1019 | return 2; | |
1020 | case DW_EH_PE_udata4: | |
1021 | return 4; | |
1022 | case DW_EH_PE_udata8: | |
1023 | return 8; | |
1024 | default: | |
1025 | internal_error (__FILE__, __LINE__, "Invalid or unsupported encoding"); | |
1026 | } | |
1027 | } | |
1028 | ||
1029 | static CORE_ADDR | |
1030 | read_encoded_value (struct comp_unit *unit, unsigned char encoding, | |
1031 | char *buf, unsigned int *bytes_read_ptr) | |
1032 | { | |
68f6cf99 MK |
1033 | int ptr_len = size_of_encoded_value (DW_EH_PE_absptr); |
1034 | ptrdiff_t offset; | |
cfc14b3a MK |
1035 | CORE_ADDR base; |
1036 | ||
1037 | /* GCC currently doesn't generate DW_EH_PE_indirect encodings for | |
1038 | FDE's. */ | |
1039 | if (encoding & DW_EH_PE_indirect) | |
1040 | internal_error (__FILE__, __LINE__, | |
1041 | "Unsupported encoding: DW_EH_PE_indirect"); | |
1042 | ||
68f6cf99 MK |
1043 | *bytes_read_ptr = 0; |
1044 | ||
cfc14b3a MK |
1045 | switch (encoding & 0x70) |
1046 | { | |
1047 | case DW_EH_PE_absptr: | |
1048 | base = 0; | |
1049 | break; | |
1050 | case DW_EH_PE_pcrel: | |
1051 | base = bfd_get_section_vma (unit->bfd, unit->dwarf_frame_section); | |
1052 | base += (buf - unit->dwarf_frame_buffer); | |
1053 | break; | |
0912c7f2 MK |
1054 | case DW_EH_PE_datarel: |
1055 | base = unit->dbase; | |
1056 | break; | |
0fd85043 CV |
1057 | case DW_EH_PE_textrel: |
1058 | base = unit->tbase; | |
1059 | break; | |
68f6cf99 MK |
1060 | case DW_EH_PE_aligned: |
1061 | base = 0; | |
1062 | offset = buf - unit->dwarf_frame_buffer; | |
1063 | if ((offset % ptr_len) != 0) | |
1064 | { | |
1065 | *bytes_read_ptr = ptr_len - (offset % ptr_len); | |
1066 | buf += *bytes_read_ptr; | |
1067 | } | |
1068 | break; | |
cfc14b3a MK |
1069 | default: |
1070 | internal_error (__FILE__, __LINE__, "Invalid or unsupported encoding"); | |
1071 | } | |
1072 | ||
1073 | if ((encoding & 0x0f) == 0x00) | |
68f6cf99 | 1074 | encoding |= encoding_for_size (ptr_len); |
cfc14b3a MK |
1075 | |
1076 | switch (encoding & 0x0f) | |
1077 | { | |
1078 | case DW_EH_PE_udata2: | |
68f6cf99 | 1079 | *bytes_read_ptr += 2; |
cfc14b3a MK |
1080 | return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf)); |
1081 | case DW_EH_PE_udata4: | |
68f6cf99 | 1082 | *bytes_read_ptr += 4; |
cfc14b3a MK |
1083 | return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf)); |
1084 | case DW_EH_PE_udata8: | |
68f6cf99 | 1085 | *bytes_read_ptr += 8; |
cfc14b3a MK |
1086 | return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf)); |
1087 | case DW_EH_PE_sdata2: | |
68f6cf99 | 1088 | *bytes_read_ptr += 2; |
cfc14b3a MK |
1089 | return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf)); |
1090 | case DW_EH_PE_sdata4: | |
68f6cf99 | 1091 | *bytes_read_ptr += 4; |
cfc14b3a MK |
1092 | return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf)); |
1093 | case DW_EH_PE_sdata8: | |
68f6cf99 | 1094 | *bytes_read_ptr += 8; |
cfc14b3a MK |
1095 | return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf)); |
1096 | default: | |
1097 | internal_error (__FILE__, __LINE__, "Invalid or unsupported encoding"); | |
1098 | } | |
1099 | } | |
1100 | \f | |
1101 | ||
1102 | /* GCC uses a single CIE for all FDEs in a .debug_frame section. | |
1103 | That's why we use a simple linked list here. */ | |
1104 | ||
1105 | static struct dwarf2_cie * | |
1106 | find_cie (struct comp_unit *unit, ULONGEST cie_pointer) | |
1107 | { | |
1108 | struct dwarf2_cie *cie = unit->cie; | |
1109 | ||
1110 | while (cie) | |
1111 | { | |
1112 | if (cie->cie_pointer == cie_pointer) | |
1113 | return cie; | |
1114 | ||
1115 | cie = cie->next; | |
1116 | } | |
1117 | ||
1118 | return NULL; | |
1119 | } | |
1120 | ||
1121 | static void | |
1122 | add_cie (struct comp_unit *unit, struct dwarf2_cie *cie) | |
1123 | { | |
1124 | cie->next = unit->cie; | |
1125 | unit->cie = cie; | |
1126 | } | |
1127 | ||
1128 | /* Find the FDE for *PC. Return a pointer to the FDE, and store the | |
1129 | inital location associated with it into *PC. */ | |
1130 | ||
1131 | static struct dwarf2_fde * | |
1132 | dwarf2_frame_find_fde (CORE_ADDR *pc) | |
1133 | { | |
1134 | struct objfile *objfile; | |
1135 | ||
1136 | ALL_OBJFILES (objfile) | |
1137 | { | |
1138 | struct dwarf2_fde *fde; | |
1139 | CORE_ADDR offset; | |
1140 | ||
0d0e1a63 | 1141 | fde = objfile_data (objfile, dwarf2_frame_data); |
4ae9ee8e DJ |
1142 | if (fde == NULL) |
1143 | continue; | |
1144 | ||
1145 | gdb_assert (objfile->section_offsets); | |
1146 | offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile)); | |
1147 | ||
cfc14b3a MK |
1148 | while (fde) |
1149 | { | |
1150 | if (*pc >= fde->initial_location + offset | |
1151 | && *pc < fde->initial_location + offset + fde->address_range) | |
1152 | { | |
1153 | *pc = fde->initial_location + offset; | |
1154 | return fde; | |
1155 | } | |
1156 | ||
1157 | fde = fde->next; | |
1158 | } | |
1159 | } | |
1160 | ||
1161 | return NULL; | |
1162 | } | |
1163 | ||
1164 | static void | |
1165 | add_fde (struct comp_unit *unit, struct dwarf2_fde *fde) | |
1166 | { | |
0d0e1a63 MK |
1167 | fde->next = objfile_data (unit->objfile, dwarf2_frame_data); |
1168 | set_objfile_data (unit->objfile, dwarf2_frame_data, fde); | |
cfc14b3a MK |
1169 | } |
1170 | ||
1171 | #ifdef CC_HAS_LONG_LONG | |
1172 | #define DW64_CIE_ID 0xffffffffffffffffULL | |
1173 | #else | |
1174 | #define DW64_CIE_ID ~0 | |
1175 | #endif | |
1176 | ||
6896c0c7 RH |
1177 | static char *decode_frame_entry (struct comp_unit *unit, char *start, |
1178 | int eh_frame_p); | |
cfc14b3a | 1179 | |
6896c0c7 RH |
1180 | /* Decode the next CIE or FDE. Return NULL if invalid input, otherwise |
1181 | the next byte to be processed. */ | |
cfc14b3a | 1182 | static char * |
6896c0c7 | 1183 | decode_frame_entry_1 (struct comp_unit *unit, char *start, int eh_frame_p) |
cfc14b3a | 1184 | { |
6896c0c7 | 1185 | char *buf; |
cfc14b3a MK |
1186 | LONGEST length; |
1187 | unsigned int bytes_read; | |
6896c0c7 RH |
1188 | int dwarf64_p; |
1189 | ULONGEST cie_id; | |
cfc14b3a | 1190 | ULONGEST cie_pointer; |
cfc14b3a MK |
1191 | char *end; |
1192 | ||
6896c0c7 | 1193 | buf = start; |
cfc14b3a MK |
1194 | length = read_initial_length (unit->abfd, buf, &bytes_read); |
1195 | buf += bytes_read; | |
1196 | end = buf + length; | |
1197 | ||
6896c0c7 RH |
1198 | /* Are we still within the section? */ |
1199 | if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size) | |
1200 | return NULL; | |
1201 | ||
cfc14b3a MK |
1202 | if (length == 0) |
1203 | return end; | |
1204 | ||
6896c0c7 RH |
1205 | /* Distinguish between 32 and 64-bit encoded frame info. */ |
1206 | dwarf64_p = (bytes_read == 12); | |
cfc14b3a | 1207 | |
6896c0c7 | 1208 | /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */ |
cfc14b3a MK |
1209 | if (eh_frame_p) |
1210 | cie_id = 0; | |
1211 | else if (dwarf64_p) | |
1212 | cie_id = DW64_CIE_ID; | |
6896c0c7 RH |
1213 | else |
1214 | cie_id = DW_CIE_ID; | |
cfc14b3a MK |
1215 | |
1216 | if (dwarf64_p) | |
1217 | { | |
1218 | cie_pointer = read_8_bytes (unit->abfd, buf); | |
1219 | buf += 8; | |
1220 | } | |
1221 | else | |
1222 | { | |
1223 | cie_pointer = read_4_bytes (unit->abfd, buf); | |
1224 | buf += 4; | |
1225 | } | |
1226 | ||
1227 | if (cie_pointer == cie_id) | |
1228 | { | |
1229 | /* This is a CIE. */ | |
1230 | struct dwarf2_cie *cie; | |
1231 | char *augmentation; | |
1232 | ||
1233 | /* Record the offset into the .debug_frame section of this CIE. */ | |
1234 | cie_pointer = start - unit->dwarf_frame_buffer; | |
1235 | ||
1236 | /* Check whether we've already read it. */ | |
1237 | if (find_cie (unit, cie_pointer)) | |
1238 | return end; | |
1239 | ||
1240 | cie = (struct dwarf2_cie *) | |
1241 | obstack_alloc (&unit->objfile->psymbol_obstack, | |
1242 | sizeof (struct dwarf2_cie)); | |
1243 | cie->initial_instructions = NULL; | |
1244 | cie->cie_pointer = cie_pointer; | |
1245 | ||
1246 | /* The encoding for FDE's in a normal .debug_frame section | |
1247 | depends on the target address size as specified in the | |
1248 | Compilation Unit Header. */ | |
1249 | cie->encoding = encoding_for_size (unit->addr_size); | |
1250 | ||
1251 | /* Check version number. */ | |
6896c0c7 RH |
1252 | if (read_1_byte (unit->abfd, buf) != DW_CIE_VERSION) |
1253 | return NULL; | |
cfc14b3a MK |
1254 | buf += 1; |
1255 | ||
1256 | /* Interpret the interesting bits of the augmentation. */ | |
1257 | augmentation = buf; | |
1258 | buf = augmentation + strlen (augmentation) + 1; | |
1259 | ||
1260 | /* The GCC 2.x "eh" augmentation has a pointer immediately | |
1261 | following the augmentation string, so it must be handled | |
1262 | first. */ | |
1263 | if (augmentation[0] == 'e' && augmentation[1] == 'h') | |
1264 | { | |
1265 | /* Skip. */ | |
1266 | buf += TYPE_LENGTH (builtin_type_void_data_ptr); | |
1267 | augmentation += 2; | |
1268 | } | |
1269 | ||
1270 | cie->code_alignment_factor = | |
1271 | read_unsigned_leb128 (unit->abfd, buf, &bytes_read); | |
1272 | buf += bytes_read; | |
1273 | ||
1274 | cie->data_alignment_factor = | |
1275 | read_signed_leb128 (unit->abfd, buf, &bytes_read); | |
1276 | buf += bytes_read; | |
1277 | ||
1278 | cie->return_address_register = read_1_byte (unit->abfd, buf); | |
1279 | buf += 1; | |
1280 | ||
7131cb6e RH |
1281 | cie->saw_z_augmentation = (*augmentation == 'z'); |
1282 | if (cie->saw_z_augmentation) | |
cfc14b3a MK |
1283 | { |
1284 | ULONGEST length; | |
1285 | ||
1286 | length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read); | |
1287 | buf += bytes_read; | |
6896c0c7 RH |
1288 | if (buf > end) |
1289 | return NULL; | |
cfc14b3a MK |
1290 | cie->initial_instructions = buf + length; |
1291 | augmentation++; | |
1292 | } | |
1293 | ||
1294 | while (*augmentation) | |
1295 | { | |
1296 | /* "L" indicates a byte showing how the LSDA pointer is encoded. */ | |
1297 | if (*augmentation == 'L') | |
1298 | { | |
1299 | /* Skip. */ | |
1300 | buf++; | |
1301 | augmentation++; | |
1302 | } | |
1303 | ||
1304 | /* "R" indicates a byte indicating how FDE addresses are encoded. */ | |
1305 | else if (*augmentation == 'R') | |
1306 | { | |
1307 | cie->encoding = *buf++; | |
1308 | augmentation++; | |
1309 | } | |
1310 | ||
1311 | /* "P" indicates a personality routine in the CIE augmentation. */ | |
1312 | else if (*augmentation == 'P') | |
1313 | { | |
1314 | /* Skip. */ | |
1315 | buf += size_of_encoded_value (*buf++); | |
1316 | augmentation++; | |
1317 | } | |
1318 | ||
1319 | /* Otherwise we have an unknown augmentation. | |
1320 | Bail out unless we saw a 'z' prefix. */ | |
1321 | else | |
1322 | { | |
1323 | if (cie->initial_instructions == NULL) | |
1324 | return end; | |
1325 | ||
1326 | /* Skip unknown augmentations. */ | |
1327 | buf = cie->initial_instructions; | |
1328 | break; | |
1329 | } | |
1330 | } | |
1331 | ||
1332 | cie->initial_instructions = buf; | |
1333 | cie->end = end; | |
1334 | ||
1335 | add_cie (unit, cie); | |
1336 | } | |
1337 | else | |
1338 | { | |
1339 | /* This is a FDE. */ | |
1340 | struct dwarf2_fde *fde; | |
1341 | ||
6896c0c7 RH |
1342 | /* In an .eh_frame section, the CIE pointer is the delta between the |
1343 | address within the FDE where the CIE pointer is stored and the | |
1344 | address of the CIE. Convert it to an offset into the .eh_frame | |
1345 | section. */ | |
cfc14b3a MK |
1346 | if (eh_frame_p) |
1347 | { | |
cfc14b3a MK |
1348 | cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer; |
1349 | cie_pointer -= (dwarf64_p ? 8 : 4); | |
1350 | } | |
1351 | ||
6896c0c7 RH |
1352 | /* In either case, validate the result is still within the section. */ |
1353 | if (cie_pointer >= unit->dwarf_frame_size) | |
1354 | return NULL; | |
1355 | ||
cfc14b3a MK |
1356 | fde = (struct dwarf2_fde *) |
1357 | obstack_alloc (&unit->objfile->psymbol_obstack, | |
1358 | sizeof (struct dwarf2_fde)); | |
1359 | fde->cie = find_cie (unit, cie_pointer); | |
1360 | if (fde->cie == NULL) | |
1361 | { | |
1362 | decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer, | |
1363 | eh_frame_p); | |
1364 | fde->cie = find_cie (unit, cie_pointer); | |
1365 | } | |
1366 | ||
1367 | gdb_assert (fde->cie != NULL); | |
1368 | ||
1369 | fde->initial_location = | |
1370 | read_encoded_value (unit, fde->cie->encoding, buf, &bytes_read); | |
1371 | buf += bytes_read; | |
1372 | ||
1373 | fde->address_range = | |
1374 | read_encoded_value (unit, fde->cie->encoding & 0x0f, buf, &bytes_read); | |
1375 | buf += bytes_read; | |
1376 | ||
7131cb6e RH |
1377 | /* A 'z' augmentation in the CIE implies the presence of an |
1378 | augmentation field in the FDE as well. The only thing known | |
1379 | to be in here at present is the LSDA entry for EH. So we | |
1380 | can skip the whole thing. */ | |
1381 | if (fde->cie->saw_z_augmentation) | |
1382 | { | |
1383 | ULONGEST length; | |
1384 | ||
1385 | length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read); | |
1386 | buf += bytes_read + length; | |
6896c0c7 RH |
1387 | if (buf > end) |
1388 | return NULL; | |
7131cb6e RH |
1389 | } |
1390 | ||
cfc14b3a MK |
1391 | fde->instructions = buf; |
1392 | fde->end = end; | |
1393 | ||
1394 | add_fde (unit, fde); | |
1395 | } | |
1396 | ||
1397 | return end; | |
1398 | } | |
6896c0c7 RH |
1399 | |
1400 | /* Read a CIE or FDE in BUF and decode it. */ | |
1401 | static char * | |
1402 | decode_frame_entry (struct comp_unit *unit, char *start, int eh_frame_p) | |
1403 | { | |
1404 | enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE; | |
1405 | char *ret; | |
1406 | const char *msg; | |
1407 | ptrdiff_t start_offset; | |
1408 | ||
1409 | while (1) | |
1410 | { | |
1411 | ret = decode_frame_entry_1 (unit, start, eh_frame_p); | |
1412 | if (ret != NULL) | |
1413 | break; | |
1414 | ||
1415 | /* We have corrupt input data of some form. */ | |
1416 | ||
1417 | /* ??? Try, weakly, to work around compiler/assembler/linker bugs | |
1418 | and mismatches wrt padding and alignment of debug sections. */ | |
1419 | /* Note that there is no requirement in the standard for any | |
1420 | alignment at all in the frame unwind sections. Testing for | |
1421 | alignment before trying to interpret data would be incorrect. | |
1422 | ||
1423 | However, GCC traditionally arranged for frame sections to be | |
1424 | sized such that the FDE length and CIE fields happen to be | |
1425 | aligned (in theory, for performance). This, unfortunately, | |
1426 | was done with .align directives, which had the side effect of | |
1427 | forcing the section to be aligned by the linker. | |
1428 | ||
1429 | This becomes a problem when you have some other producer that | |
1430 | creates frame sections that are not as strictly aligned. That | |
1431 | produces a hole in the frame info that gets filled by the | |
1432 | linker with zeros. | |
1433 | ||
1434 | The GCC behaviour is arguably a bug, but it's effectively now | |
1435 | part of the ABI, so we're now stuck with it, at least at the | |
1436 | object file level. A smart linker may decide, in the process | |
1437 | of compressing duplicate CIE information, that it can rewrite | |
1438 | the entire output section without this extra padding. */ | |
1439 | ||
1440 | start_offset = start - unit->dwarf_frame_buffer; | |
1441 | if (workaround < ALIGN4 && (start_offset & 3) != 0) | |
1442 | { | |
1443 | start += 4 - (start_offset & 3); | |
1444 | workaround = ALIGN4; | |
1445 | continue; | |
1446 | } | |
1447 | if (workaround < ALIGN8 && (start_offset & 7) != 0) | |
1448 | { | |
1449 | start += 8 - (start_offset & 7); | |
1450 | workaround = ALIGN8; | |
1451 | continue; | |
1452 | } | |
1453 | ||
1454 | /* Nothing left to try. Arrange to return as if we've consumed | |
1455 | the entire input section. Hopefully we'll get valid info from | |
1456 | the other of .debug_frame/.eh_frame. */ | |
1457 | workaround = FAIL; | |
1458 | ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size; | |
1459 | break; | |
1460 | } | |
1461 | ||
1462 | switch (workaround) | |
1463 | { | |
1464 | case NONE: | |
1465 | break; | |
1466 | ||
1467 | case ALIGN4: | |
1468 | complaint (&symfile_complaints, | |
1469 | "Corrupt data in %s:%s; align 4 workaround apparently succeeded", | |
1470 | unit->dwarf_frame_section->owner->filename, | |
1471 | unit->dwarf_frame_section->name); | |
1472 | break; | |
1473 | ||
1474 | case ALIGN8: | |
1475 | complaint (&symfile_complaints, | |
1476 | "Corrupt data in %s:%s; align 8 workaround apparently succeeded", | |
1477 | unit->dwarf_frame_section->owner->filename, | |
1478 | unit->dwarf_frame_section->name); | |
1479 | break; | |
1480 | ||
1481 | default: | |
1482 | complaint (&symfile_complaints, | |
1483 | "Corrupt data in %s:%s", | |
1484 | unit->dwarf_frame_section->owner->filename, | |
1485 | unit->dwarf_frame_section->name); | |
1486 | break; | |
1487 | } | |
1488 | ||
1489 | return ret; | |
1490 | } | |
1491 | ||
cfc14b3a MK |
1492 | \f |
1493 | ||
1494 | /* FIXME: kettenis/20030504: This still needs to be integrated with | |
1495 | dwarf2read.c in a better way. */ | |
1496 | ||
1497 | /* Imported from dwarf2read.c. */ | |
cfc14b3a | 1498 | extern asection *dwarf_frame_section; |
cfc14b3a MK |
1499 | extern asection *dwarf_eh_frame_section; |
1500 | ||
1501 | /* Imported from dwarf2read.c. */ | |
188dd5d6 | 1502 | extern char *dwarf2_read_section (struct objfile *objfile, asection *sectp); |
cfc14b3a MK |
1503 | |
1504 | void | |
1505 | dwarf2_build_frame_info (struct objfile *objfile) | |
1506 | { | |
1507 | struct comp_unit unit; | |
1508 | char *frame_ptr; | |
1509 | ||
1510 | /* Build a minimal decoding of the DWARF2 compilation unit. */ | |
1511 | unit.abfd = objfile->obfd; | |
1512 | unit.objfile = objfile; | |
1513 | unit.addr_size = objfile->obfd->arch_info->bits_per_address / 8; | |
0912c7f2 | 1514 | unit.dbase = 0; |
0fd85043 | 1515 | unit.tbase = 0; |
cfc14b3a MK |
1516 | |
1517 | /* First add the information from the .eh_frame section. That way, | |
1518 | the FDEs from that section are searched last. */ | |
188dd5d6 | 1519 | if (dwarf_eh_frame_section) |
cfc14b3a | 1520 | { |
0fd85043 | 1521 | asection *got, *txt; |
0912c7f2 | 1522 | |
cfc14b3a MK |
1523 | unit.cie = NULL; |
1524 | unit.dwarf_frame_buffer = dwarf2_read_section (objfile, | |
cfc14b3a MK |
1525 | dwarf_eh_frame_section); |
1526 | ||
188dd5d6 DJ |
1527 | unit.dwarf_frame_size |
1528 | = bfd_get_section_size_before_reloc (dwarf_eh_frame_section); | |
cfc14b3a MK |
1529 | unit.dwarf_frame_section = dwarf_eh_frame_section; |
1530 | ||
0912c7f2 | 1531 | /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base |
37b517aa MK |
1532 | that is used for the i386/amd64 target, which currently is |
1533 | the only target in GCC that supports/uses the | |
1534 | DW_EH_PE_datarel encoding. */ | |
0912c7f2 MK |
1535 | got = bfd_get_section_by_name (unit.abfd, ".got"); |
1536 | if (got) | |
1537 | unit.dbase = got->vma; | |
1538 | ||
22c7ba1a MK |
1539 | /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64 |
1540 | so far. */ | |
0fd85043 CV |
1541 | txt = bfd_get_section_by_name (unit.abfd, ".text"); |
1542 | if (txt) | |
1543 | unit.tbase = txt->vma; | |
1544 | ||
cfc14b3a MK |
1545 | frame_ptr = unit.dwarf_frame_buffer; |
1546 | while (frame_ptr < unit.dwarf_frame_buffer + unit.dwarf_frame_size) | |
1547 | frame_ptr = decode_frame_entry (&unit, frame_ptr, 1); | |
1548 | } | |
1549 | ||
188dd5d6 | 1550 | if (dwarf_frame_section) |
cfc14b3a MK |
1551 | { |
1552 | unit.cie = NULL; | |
1553 | unit.dwarf_frame_buffer = dwarf2_read_section (objfile, | |
cfc14b3a | 1554 | dwarf_frame_section); |
188dd5d6 DJ |
1555 | unit.dwarf_frame_size |
1556 | = bfd_get_section_size_before_reloc (dwarf_frame_section); | |
cfc14b3a MK |
1557 | unit.dwarf_frame_section = dwarf_frame_section; |
1558 | ||
1559 | frame_ptr = unit.dwarf_frame_buffer; | |
1560 | while (frame_ptr < unit.dwarf_frame_buffer + unit.dwarf_frame_size) | |
1561 | frame_ptr = decode_frame_entry (&unit, frame_ptr, 0); | |
1562 | } | |
1563 | } | |
0d0e1a63 MK |
1564 | |
1565 | /* Provide a prototype to silence -Wmissing-prototypes. */ | |
1566 | void _initialize_dwarf2_frame (void); | |
1567 | ||
1568 | void | |
1569 | _initialize_dwarf2_frame (void) | |
1570 | { | |
1571 | dwarf2_frame_data = register_objfile_data (); | |
1572 | } |