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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 | ||
39 | #include "dwarf2-frame.h" | |
40 | ||
41 | /* Call Frame Information (CFI). */ | |
42 | ||
43 | /* Common Information Entry (CIE). */ | |
44 | ||
45 | struct dwarf2_cie | |
46 | { | |
47 | /* Offset into the .debug_frame section where this CIE was found. | |
48 | Used to identify this CIE. */ | |
49 | ULONGEST cie_pointer; | |
50 | ||
51 | /* Constant that is factored out of all advance location | |
52 | instructions. */ | |
53 | ULONGEST code_alignment_factor; | |
54 | ||
55 | /* Constants that is factored out of all offset instructions. */ | |
56 | LONGEST data_alignment_factor; | |
57 | ||
58 | /* Return address column. */ | |
59 | ULONGEST return_address_register; | |
60 | ||
61 | /* Instruction sequence to initialize a register set. */ | |
62 | unsigned char *initial_instructions; | |
63 | unsigned char *end; | |
64 | ||
65 | /* Encoding of addresses. */ | |
66 | unsigned char encoding; | |
67 | ||
68 | struct dwarf2_cie *next; | |
69 | }; | |
70 | ||
71 | /* Frame Description Entry (FDE). */ | |
72 | ||
73 | struct dwarf2_fde | |
74 | { | |
75 | /* CIE for this FDE. */ | |
76 | struct dwarf2_cie *cie; | |
77 | ||
78 | /* First location associated with this FDE. */ | |
79 | CORE_ADDR initial_location; | |
80 | ||
81 | /* Number of bytes of program instructions described by this FDE. */ | |
82 | CORE_ADDR address_range; | |
83 | ||
84 | /* Instruction sequence. */ | |
85 | unsigned char *instructions; | |
86 | unsigned char *end; | |
87 | ||
88 | struct dwarf2_fde *next; | |
89 | }; | |
90 | ||
91 | static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc); | |
92 | \f | |
93 | ||
94 | /* Structure describing a frame state. */ | |
95 | ||
96 | struct dwarf2_frame_state | |
97 | { | |
98 | /* Each register save state can be described in terms of a CFA slot, | |
99 | another register, or a location expression. */ | |
100 | struct dwarf2_frame_state_reg_info | |
101 | { | |
102 | struct dwarf2_frame_state_reg | |
103 | { | |
104 | union { | |
105 | LONGEST offset; | |
106 | ULONGEST reg; | |
107 | unsigned char *exp; | |
108 | } loc; | |
109 | ULONGEST exp_len; | |
110 | enum { | |
111 | REG_UNSAVED, | |
112 | REG_SAVED_OFFSET, | |
113 | REG_SAVED_REG, | |
114 | REG_SAVED_EXP, | |
115 | REG_UNMODIFIED | |
116 | } how; | |
117 | } *reg; | |
118 | int num_regs; | |
119 | ||
120 | /* Used to implement DW_CFA_remember_state. */ | |
121 | struct dwarf2_frame_state_reg_info *prev; | |
122 | } regs; | |
123 | ||
124 | LONGEST cfa_offset; | |
125 | ULONGEST cfa_reg; | |
126 | unsigned char *cfa_exp; | |
127 | enum { | |
128 | CFA_UNSET, | |
129 | CFA_REG_OFFSET, | |
130 | CFA_EXP | |
131 | } cfa_how; | |
132 | ||
133 | /* The PC described by the current frame state. */ | |
134 | CORE_ADDR pc; | |
135 | ||
136 | /* Initial register set from the CIE. | |
137 | Used to implement DW_CFA_restore. */ | |
138 | struct dwarf2_frame_state_reg_info initial; | |
139 | ||
140 | /* The information we care about from the CIE. */ | |
141 | LONGEST data_align; | |
142 | ULONGEST code_align; | |
143 | ULONGEST retaddr_column; | |
144 | }; | |
145 | ||
146 | /* Store the length the expression for the CFA in the `cfa_reg' field, | |
147 | which is unused in that case. */ | |
148 | #define cfa_exp_len cfa_reg | |
149 | ||
150 | /* Assert that the register set RS is large enough to store NUM_REGS | |
151 | columns. If necessary, enlarge the register set. */ | |
152 | ||
153 | static void | |
154 | dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs, | |
155 | int num_regs) | |
156 | { | |
157 | size_t size = sizeof (struct dwarf2_frame_state_reg); | |
158 | ||
159 | if (num_regs <= rs->num_regs) | |
160 | return; | |
161 | ||
162 | rs->reg = (struct dwarf2_frame_state_reg *) | |
163 | xrealloc (rs->reg, num_regs * size); | |
164 | ||
165 | /* Initialize newly allocated registers. */ | |
166 | memset (rs->reg + rs->num_regs * size, 0, (num_regs - rs->num_regs) * size); | |
167 | rs->num_regs = num_regs; | |
168 | } | |
169 | ||
170 | /* Copy the register columns in register set RS into newly allocated | |
171 | memory and return a pointer to this newly created copy. */ | |
172 | ||
173 | static struct dwarf2_frame_state_reg * | |
174 | dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs) | |
175 | { | |
176 | size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg_info); | |
177 | struct dwarf2_frame_state_reg *reg; | |
178 | ||
179 | reg = (struct dwarf2_frame_state_reg *) xmalloc (size); | |
180 | memcpy (reg, rs->reg, size); | |
181 | ||
182 | return reg; | |
183 | } | |
184 | ||
185 | /* Release the memory allocated to register set RS. */ | |
186 | ||
187 | static void | |
188 | dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs) | |
189 | { | |
190 | if (rs) | |
191 | { | |
192 | dwarf2_frame_state_free_regs (rs->prev); | |
193 | ||
194 | xfree (rs->reg); | |
195 | xfree (rs); | |
196 | } | |
197 | } | |
198 | ||
199 | /* Release the memory allocated to the frame state FS. */ | |
200 | ||
201 | static void | |
202 | dwarf2_frame_state_free (void *p) | |
203 | { | |
204 | struct dwarf2_frame_state *fs = p; | |
205 | ||
206 | dwarf2_frame_state_free_regs (fs->initial.prev); | |
207 | dwarf2_frame_state_free_regs (fs->regs.prev); | |
208 | xfree (fs->initial.reg); | |
209 | xfree (fs->regs.reg); | |
210 | xfree (fs); | |
211 | } | |
212 | \f | |
213 | ||
214 | /* Helper functions for execute_stack_op. */ | |
215 | ||
216 | static CORE_ADDR | |
217 | read_reg (void *baton, int reg) | |
218 | { | |
219 | struct frame_info *next_frame = (struct frame_info *) baton; | |
220 | int regnum; | |
221 | char *buf; | |
222 | ||
223 | regnum = DWARF2_REG_TO_REGNUM (reg); | |
224 | ||
225 | buf = (char *) alloca (register_size (current_gdbarch, regnum)); | |
226 | frame_unwind_register (next_frame, regnum, buf); | |
227 | return extract_typed_address (buf, builtin_type_void_data_ptr); | |
228 | } | |
229 | ||
230 | static void | |
231 | read_mem (void *baton, char *buf, CORE_ADDR addr, size_t len) | |
232 | { | |
233 | read_memory (addr, buf, len); | |
234 | } | |
235 | ||
236 | static void | |
237 | no_get_frame_base (void *baton, unsigned char **start, size_t *length) | |
238 | { | |
239 | internal_error (__FILE__, __LINE__, | |
240 | "Support for DW_OP_fbreg is unimplemented"); | |
241 | } | |
242 | ||
243 | static CORE_ADDR | |
244 | no_get_tls_address (void *baton, CORE_ADDR offset) | |
245 | { | |
246 | internal_error (__FILE__, __LINE__, | |
247 | "Support for DW_OP_GNU_push_tls_address is unimplemented"); | |
248 | } | |
249 | ||
250 | static CORE_ADDR | |
251 | execute_stack_op (unsigned char *exp, ULONGEST len, | |
252 | struct frame_info *next_frame, CORE_ADDR initial) | |
253 | { | |
254 | struct dwarf_expr_context *ctx; | |
255 | CORE_ADDR result; | |
256 | ||
257 | ctx = new_dwarf_expr_context (); | |
258 | ctx->baton = next_frame; | |
259 | ctx->read_reg = read_reg; | |
260 | ctx->read_mem = read_mem; | |
261 | ctx->get_frame_base = no_get_frame_base; | |
262 | ctx->get_tls_address = no_get_tls_address; | |
263 | ||
264 | dwarf_expr_push (ctx, initial); | |
265 | dwarf_expr_eval (ctx, exp, len); | |
266 | result = dwarf_expr_fetch (ctx, 0); | |
267 | ||
268 | if (ctx->in_reg) | |
269 | result = read_reg (next_frame, result); | |
270 | ||
271 | free_dwarf_expr_context (ctx); | |
272 | ||
273 | return result; | |
274 | } | |
275 | \f | |
276 | ||
277 | static void | |
278 | execute_cfa_program (unsigned char *insn_ptr, unsigned char *insn_end, | |
279 | struct frame_info *next_frame, | |
280 | struct dwarf2_frame_state *fs) | |
281 | { | |
282 | CORE_ADDR pc = frame_pc_unwind (next_frame); | |
283 | int bytes_read; | |
284 | ||
285 | while (insn_ptr < insn_end && fs->pc <= pc) | |
286 | { | |
287 | unsigned char insn = *insn_ptr++; | |
288 | ULONGEST utmp, reg; | |
289 | LONGEST offset; | |
290 | ||
291 | if ((insn & 0xc0) == DW_CFA_advance_loc) | |
292 | fs->pc += (insn & 0x3f) * fs->code_align; | |
293 | else if ((insn & 0xc0) == DW_CFA_offset) | |
294 | { | |
295 | reg = insn & 0x3f; | |
296 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
297 | offset = utmp * fs->data_align; | |
298 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
299 | fs->regs.reg[reg].how = REG_SAVED_OFFSET; | |
300 | fs->regs.reg[reg].loc.offset = offset; | |
301 | } | |
302 | else if ((insn & 0xc0) == DW_CFA_restore) | |
303 | { | |
304 | gdb_assert (fs->initial.reg); | |
305 | reg = insn & 0x3f; | |
306 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
307 | fs->regs.reg[reg] = fs->initial.reg[reg]; | |
308 | } | |
309 | else | |
310 | { | |
311 | switch (insn) | |
312 | { | |
313 | case DW_CFA_set_loc: | |
314 | fs->pc = dwarf2_read_address (insn_ptr, insn_end, &bytes_read); | |
315 | insn_ptr += bytes_read; | |
316 | break; | |
317 | ||
318 | case DW_CFA_advance_loc1: | |
319 | utmp = extract_unsigned_integer (insn_ptr, 1); | |
320 | fs->pc += utmp * fs->code_align; | |
321 | insn_ptr++; | |
322 | break; | |
323 | case DW_CFA_advance_loc2: | |
324 | utmp = extract_unsigned_integer (insn_ptr, 2); | |
325 | fs->pc += utmp * fs->code_align; | |
326 | insn_ptr += 2; | |
327 | break; | |
328 | case DW_CFA_advance_loc4: | |
329 | utmp = extract_unsigned_integer (insn_ptr, 4); | |
330 | fs->pc += utmp * fs->code_align; | |
331 | insn_ptr += 4; | |
332 | break; | |
333 | ||
334 | case DW_CFA_offset_extended: | |
335 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
336 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
337 | offset = utmp * fs->data_align; | |
338 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
339 | fs->regs.reg[reg].how = REG_SAVED_OFFSET; | |
340 | fs->regs.reg[reg].loc.offset = offset; | |
341 | break; | |
342 | ||
343 | case DW_CFA_restore_extended: | |
344 | gdb_assert (fs->initial.reg); | |
345 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
346 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
347 | fs->regs.reg[reg] = fs->initial.reg[reg]; | |
348 | break; | |
349 | ||
350 | case DW_CFA_undefined: | |
351 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
352 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
353 | fs->regs.reg[reg].how = REG_UNSAVED; | |
354 | break; | |
355 | ||
356 | case DW_CFA_same_value: | |
357 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
358 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
359 | fs->regs.reg[reg].how = REG_UNMODIFIED; | |
360 | break; | |
361 | ||
362 | case DW_CFA_register: | |
363 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
364 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
365 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
366 | fs->regs.reg[reg].loc.reg = utmp; | |
367 | break; | |
368 | ||
369 | case DW_CFA_remember_state: | |
370 | { | |
371 | struct dwarf2_frame_state_reg_info *new_rs; | |
372 | ||
373 | new_rs = XMALLOC (struct dwarf2_frame_state_reg_info); | |
374 | *new_rs = fs->regs; | |
375 | fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs); | |
376 | fs->regs.prev = new_rs; | |
377 | } | |
378 | break; | |
379 | ||
380 | case DW_CFA_restore_state: | |
381 | { | |
382 | struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev; | |
383 | ||
384 | gdb_assert (old_rs); | |
385 | ||
386 | xfree (fs->regs.reg); | |
387 | fs->regs = *old_rs; | |
388 | xfree (old_rs); | |
389 | } | |
390 | break; | |
391 | ||
392 | case DW_CFA_def_cfa: | |
393 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); | |
394 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
395 | fs->cfa_offset = utmp; | |
396 | fs->cfa_how = CFA_REG_OFFSET; | |
397 | break; | |
398 | ||
399 | case DW_CFA_def_cfa_register: | |
400 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); | |
401 | fs->cfa_how = CFA_REG_OFFSET; | |
402 | break; | |
403 | ||
404 | case DW_CFA_def_cfa_offset: | |
405 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_offset); | |
406 | /* cfa_how deliberately not set. */ | |
407 | break; | |
408 | ||
409 | case DW_CFA_def_cfa_expression: | |
410 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_exp_len); | |
411 | fs->cfa_exp = insn_ptr; | |
412 | fs->cfa_how = CFA_EXP; | |
413 | insn_ptr += fs->cfa_exp_len; | |
414 | break; | |
415 | ||
416 | case DW_CFA_expression: | |
417 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); | |
418 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); | |
419 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
420 | fs->regs.reg[reg].loc.exp = insn_ptr; | |
421 | fs->regs.reg[reg].exp_len = utmp; | |
422 | fs->regs.reg[reg].how = REG_SAVED_EXP; | |
423 | insn_ptr += utmp; | |
424 | break; | |
425 | ||
426 | case DW_CFA_nop: | |
427 | break; | |
428 | ||
429 | case DW_CFA_GNU_args_size: | |
430 | /* Ignored. */ | |
431 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); | |
432 | break; | |
433 | ||
434 | default: | |
435 | internal_error (__FILE__, __LINE__, "Unknown CFI encountered."); | |
436 | } | |
437 | } | |
438 | } | |
439 | ||
440 | /* Don't allow remember/restore between CIE and FDE programs. */ | |
441 | dwarf2_frame_state_free_regs (fs->regs.prev); | |
442 | fs->regs.prev = NULL; | |
443 | } | |
444 | ||
445 | struct dwarf2_frame_cache | |
446 | { | |
447 | /* DWARF Call Frame Address. */ | |
448 | CORE_ADDR cfa; | |
449 | ||
450 | /* Saved registers, indexed by GDB register number, not by DWARF | |
451 | register number. */ | |
452 | struct dwarf2_frame_state_reg *reg; | |
453 | }; | |
454 | ||
455 | struct dwarf2_frame_cache * | |
456 | dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache) | |
457 | { | |
458 | struct cleanup *old_chain; | |
459 | int num_regs = NUM_REGS + NUM_PSEUDO_REGS; | |
460 | struct dwarf2_frame_cache *cache; | |
461 | struct dwarf2_frame_state *fs; | |
462 | struct dwarf2_fde *fde; | |
463 | int reg; | |
464 | ||
465 | if (*this_cache) | |
466 | return *this_cache; | |
467 | ||
468 | /* Allocate a new cache. */ | |
469 | cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache); | |
470 | cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg); | |
471 | ||
472 | /* Allocate and initialize the frame state. */ | |
473 | fs = XMALLOC (struct dwarf2_frame_state); | |
474 | memset (fs, 0, sizeof (struct dwarf2_frame_state)); | |
475 | old_chain = make_cleanup (dwarf2_frame_state_free, fs); | |
476 | ||
477 | /* Unwind the PC. | |
478 | ||
479 | Note that if NEXT_FRAME is never supposed to return (i.e. a call | |
480 | to abort), the compiler might optimize away the instruction at | |
481 | NEXT_FRAME's return address. As a result the return address will | |
482 | point at some random instruction, and the CFI for that | |
483 | instruction is probably wortless to us. GCC's unwinder solves | |
484 | this problem by substracting 1 from the return address to get an | |
485 | address in the middle of a presumed call instruction (or the | |
486 | instruction in the associated delay slot). This should only be | |
487 | done for "normal" frames and not for resume-type frames (signal | |
488 | handlers, sentinel frames, dummy frames). | |
489 | ||
490 | We don't do what GCC's does here (yet). It's not clear how | |
491 | reliable the method is. There's also a problem with finding the | |
492 | right FDE; see the comment in dwarf_frame_p. If dwarf_frame_p | |
493 | selected this frame unwinder because it found the FDE for the | |
494 | next function, using the adjusted return address might not yield | |
495 | a FDE at all. The problem isn't specific to DWARF CFI; other | |
496 | unwinders loose in similar ways. Therefore it's probably | |
497 | acceptable to leave things slightly broken for now. */ | |
498 | fs->pc = frame_pc_unwind (next_frame); | |
499 | ||
500 | /* Find the correct FDE. */ | |
501 | fde = dwarf2_frame_find_fde (&fs->pc); | |
502 | gdb_assert (fde != NULL); | |
503 | ||
504 | /* Extract any interesting information from the CIE. */ | |
505 | fs->data_align = fde->cie->data_alignment_factor; | |
506 | fs->code_align = fde->cie->code_alignment_factor; | |
507 | fs->retaddr_column = fde->cie->return_address_register; | |
508 | ||
509 | /* First decode all the insns in the CIE. */ | |
510 | execute_cfa_program (fde->cie->initial_instructions, | |
511 | fde->cie->end, next_frame, fs); | |
512 | ||
513 | /* Save the initialized register set. */ | |
514 | fs->initial = fs->regs; | |
515 | fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs); | |
516 | ||
517 | /* Then decode the insns in the FDE up to our target PC. */ | |
518 | execute_cfa_program (fde->instructions, fde->end, next_frame, fs); | |
519 | ||
520 | /* Caclulate the CFA. */ | |
521 | switch (fs->cfa_how) | |
522 | { | |
523 | case CFA_REG_OFFSET: | |
524 | cache->cfa = read_reg (next_frame, fs->cfa_reg); | |
525 | cache->cfa += fs->cfa_offset; | |
526 | break; | |
527 | ||
528 | case CFA_EXP: | |
529 | cache->cfa = | |
530 | execute_stack_op (fs->cfa_exp, fs->cfa_exp_len, next_frame, 0); | |
531 | break; | |
532 | ||
533 | default: | |
534 | internal_error (__FILE__, __LINE__, "Unknown CFA rule."); | |
535 | } | |
536 | ||
537 | /* Save the register info in the cache. */ | |
538 | for (reg = 0; reg < fs->regs.num_regs; reg++) | |
539 | { | |
540 | int regnum; | |
541 | ||
542 | /* Skip the return address column. */ | |
543 | if (reg == fs->retaddr_column) | |
544 | continue; | |
545 | ||
546 | /* Use the GDB register number as index. */ | |
547 | regnum = DWARF2_REG_TO_REGNUM (reg); | |
548 | ||
549 | if (regnum >= 0 && regnum < num_regs) | |
550 | cache->reg[regnum] = fs->regs.reg[reg]; | |
551 | } | |
552 | ||
553 | /* Stored the location of the return addess. */ | |
554 | if (fs->retaddr_column < fs->regs.num_regs) | |
555 | cache->reg[PC_REGNUM] = fs->regs.reg[fs->retaddr_column]; | |
556 | ||
557 | do_cleanups (old_chain); | |
558 | ||
559 | *this_cache = cache; | |
560 | return cache; | |
561 | } | |
562 | ||
563 | static void | |
564 | dwarf2_frame_this_id (struct frame_info *next_frame, void **this_cache, | |
565 | struct frame_id *this_id) | |
566 | { | |
567 | struct dwarf2_frame_cache *cache = | |
568 | dwarf2_frame_cache (next_frame, this_cache); | |
569 | ||
570 | (*this_id) = frame_id_build (cache->cfa, frame_func_unwind (next_frame)); | |
571 | } | |
572 | ||
573 | static void | |
574 | dwarf2_frame_prev_register (struct frame_info *next_frame, void **this_cache, | |
575 | int regnum, int *optimizedp, | |
576 | enum lval_type *lvalp, CORE_ADDR *addrp, | |
577 | int *realnump, void *valuep) | |
578 | { | |
579 | struct dwarf2_frame_cache *cache = | |
580 | dwarf2_frame_cache (next_frame, this_cache); | |
581 | ||
582 | switch (cache->reg[regnum].how) | |
583 | { | |
584 | case REG_UNSAVED: | |
585 | *optimizedp = 1; | |
586 | *lvalp = not_lval; | |
587 | *addrp = 0; | |
588 | *realnump = -1; | |
589 | if (regnum == SP_REGNUM) | |
590 | { | |
591 | /* GCC defines the CFA as the value of the stack pointer | |
592 | just before the call instruction is executed. Do other | |
593 | compilers use the same definition? */ | |
594 | *optimizedp = 0; | |
595 | if (valuep) | |
596 | { | |
597 | /* Store the value. */ | |
598 | store_typed_address (valuep, builtin_type_void_data_ptr, | |
599 | cache->cfa); | |
600 | } | |
601 | } | |
602 | else if (valuep) | |
603 | { | |
604 | /* In some cases, for example %eflags on the i386, we have | |
605 | to provide a sane value, even though this register wasn't | |
606 | saved. Assume we can get it from NEXT_FRAME. */ | |
607 | frame_unwind_register (next_frame, regnum, valuep); | |
608 | } | |
609 | break; | |
610 | ||
611 | case REG_SAVED_OFFSET: | |
612 | *optimizedp = 0; | |
613 | *lvalp = lval_memory; | |
614 | *addrp = cache->cfa + cache->reg[regnum].loc.offset; | |
615 | *realnump = -1; | |
616 | if (valuep) | |
617 | { | |
618 | /* Read the value in from memory. */ | |
619 | read_memory (*addrp, valuep, | |
620 | register_size (current_gdbarch, regnum)); | |
621 | } | |
622 | break; | |
623 | ||
624 | case REG_SAVED_REG: | |
625 | regnum = DWARF2_REG_TO_REGNUM (cache->reg[regnum].loc.reg); | |
626 | frame_register_unwind (next_frame, regnum, | |
627 | optimizedp, lvalp, addrp, realnump, valuep); | |
628 | break; | |
629 | ||
630 | case REG_SAVED_EXP: | |
631 | *optimizedp = 0; | |
632 | *lvalp = lval_memory; | |
633 | *addrp = execute_stack_op (cache->reg[regnum].loc.exp, | |
634 | cache->reg[regnum].exp_len, | |
635 | next_frame, cache->cfa); | |
636 | *realnump = -1; | |
637 | if (valuep) | |
638 | { | |
639 | /* Read the value in from memory. */ | |
640 | read_memory (*addrp, valuep, | |
641 | register_size (current_gdbarch, regnum)); | |
642 | } | |
643 | break; | |
644 | ||
645 | case REG_UNMODIFIED: | |
646 | frame_register_unwind (next_frame, regnum, | |
647 | optimizedp, lvalp, addrp, realnump, valuep); | |
648 | break; | |
649 | ||
650 | default: | |
651 | internal_error (__FILE__, __LINE__, "Unknown register rule."); | |
652 | } | |
653 | } | |
654 | ||
655 | static const struct frame_unwind dwarf2_frame_unwind = | |
656 | { | |
657 | NORMAL_FRAME, | |
658 | dwarf2_frame_this_id, | |
659 | dwarf2_frame_prev_register | |
660 | }; | |
661 | ||
662 | const struct frame_unwind * | |
663 | dwarf2_frame_p (CORE_ADDR pc) | |
664 | { | |
665 | /* The way GDB works, this function can be called with PC just after | |
666 | the last instruction of the function we're supposed to return the | |
667 | unwind methods for. In that case we won't find the correct FDE; | |
668 | instead we find the FDE for the next function, or we won't find | |
669 | an FDE at all. There is a possible solution (see the comment in | |
670 | dwarf2_frame_cache), GDB doesn't pass us enough information to | |
671 | implement it. */ | |
672 | if (dwarf2_frame_find_fde (&pc)) | |
673 | return &dwarf2_frame_unwind; | |
674 | ||
675 | return NULL; | |
676 | } | |
677 | \f | |
678 | ||
679 | /* There is no explicitly defined relationship between the CFA and the | |
680 | location of frame's local variables and arguments/parameters. | |
681 | Therefore, frame base methods on this page should probably only be | |
682 | used as a last resort, just to avoid printing total garbage as a | |
683 | response to the "info frame" command. */ | |
684 | ||
685 | static CORE_ADDR | |
686 | dwarf2_frame_base_address (struct frame_info *next_frame, void **this_cache) | |
687 | { | |
688 | struct dwarf2_frame_cache *cache = | |
689 | dwarf2_frame_cache (next_frame, this_cache); | |
690 | ||
691 | return cache->cfa; | |
692 | } | |
693 | ||
694 | static const struct frame_base dwarf2_frame_base = | |
695 | { | |
696 | &dwarf2_frame_unwind, | |
697 | dwarf2_frame_base_address, | |
698 | dwarf2_frame_base_address, | |
699 | dwarf2_frame_base_address | |
700 | }; | |
701 | ||
702 | const struct frame_base * | |
703 | dwarf2_frame_base_p (CORE_ADDR pc) | |
704 | { | |
705 | if (dwarf2_frame_find_fde (&pc)) | |
706 | return &dwarf2_frame_base; | |
707 | ||
708 | return NULL; | |
709 | } | |
710 | \f | |
711 | /* A minimal decoding of DWARF2 compilation units. We only decode | |
712 | what's needed to get to the call frame information. */ | |
713 | ||
714 | struct comp_unit | |
715 | { | |
716 | /* Keep the bfd convenient. */ | |
717 | bfd *abfd; | |
718 | ||
719 | struct objfile *objfile; | |
720 | ||
721 | /* Linked list of CIEs for this object. */ | |
722 | struct dwarf2_cie *cie; | |
723 | ||
724 | /* Address size for this unit - from unit header. */ | |
725 | unsigned char addr_size; | |
726 | ||
727 | /* Pointer to the .debug_frame section loaded into memory. */ | |
728 | char *dwarf_frame_buffer; | |
729 | ||
730 | /* Length of the loaded .debug_frame section. */ | |
731 | unsigned long dwarf_frame_size; | |
732 | ||
733 | /* Pointer to the .debug_frame section. */ | |
734 | asection *dwarf_frame_section; | |
735 | }; | |
736 | ||
737 | static unsigned int | |
738 | read_1_byte (bfd *bfd, char *buf) | |
739 | { | |
740 | return bfd_get_8 (abfd, (bfd_byte *) buf); | |
741 | } | |
742 | ||
743 | static unsigned int | |
744 | read_4_bytes (bfd *abfd, char *buf) | |
745 | { | |
746 | return bfd_get_32 (abfd, (bfd_byte *) buf); | |
747 | } | |
748 | ||
749 | static ULONGEST | |
750 | read_8_bytes (bfd *abfd, char *buf) | |
751 | { | |
752 | return bfd_get_64 (abfd, (bfd_byte *) buf); | |
753 | } | |
754 | ||
755 | static ULONGEST | |
756 | read_unsigned_leb128 (bfd *abfd, char *buf, unsigned int *bytes_read_ptr) | |
757 | { | |
758 | ULONGEST result; | |
759 | unsigned int num_read; | |
760 | int shift; | |
761 | unsigned char byte; | |
762 | ||
763 | result = 0; | |
764 | shift = 0; | |
765 | num_read = 0; | |
766 | ||
767 | do | |
768 | { | |
769 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); | |
770 | buf++; | |
771 | num_read++; | |
772 | result |= ((byte & 0x7f) << shift); | |
773 | shift += 7; | |
774 | } | |
775 | while (byte & 0x80); | |
776 | ||
777 | *bytes_read_ptr = num_read; | |
778 | ||
779 | return result; | |
780 | } | |
781 | ||
782 | static LONGEST | |
783 | read_signed_leb128 (bfd *abfd, char *buf, unsigned int *bytes_read_ptr) | |
784 | { | |
785 | LONGEST result; | |
786 | int shift; | |
787 | unsigned int num_read; | |
788 | unsigned char byte; | |
789 | ||
790 | result = 0; | |
791 | shift = 0; | |
792 | num_read = 0; | |
793 | ||
794 | do | |
795 | { | |
796 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); | |
797 | buf++; | |
798 | num_read++; | |
799 | result |= ((byte & 0x7f) << shift); | |
800 | shift += 7; | |
801 | } | |
802 | while (byte & 0x80); | |
803 | ||
804 | if ((shift < 32) && (byte & 0x40)) | |
805 | result |= -(1 << shift); | |
806 | ||
807 | *bytes_read_ptr = num_read; | |
808 | ||
809 | return result; | |
810 | } | |
811 | ||
812 | static ULONGEST | |
813 | read_initial_length (bfd *abfd, char *buf, unsigned int *bytes_read_ptr) | |
814 | { | |
815 | LONGEST result; | |
816 | ||
817 | result = bfd_get_32 (abfd, (bfd_byte *) buf); | |
818 | if (result == 0xffffffff) | |
819 | { | |
820 | result = bfd_get_64 (abfd, (bfd_byte *) buf + 4); | |
821 | *bytes_read_ptr = 12; | |
822 | } | |
823 | else | |
824 | *bytes_read_ptr = 4; | |
825 | ||
826 | return result; | |
827 | } | |
828 | \f | |
829 | ||
830 | /* Pointer encoding helper functions. */ | |
831 | ||
832 | /* GCC supports exception handling based on DWARF2 CFI. However, for | |
833 | technical reasons, it encodes addresses in its FDE's in a different | |
834 | way. Several "pointer encodings" are supported. The encoding | |
835 | that's used for a particular FDE is determined by the 'R' | |
836 | augmentation in the associated CIE. The argument of this | |
837 | augmentation is a single byte. | |
838 | ||
839 | The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a | |
840 | LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether | |
841 | the address is signed or unsigned. Bits 4, 5 and 6 encode how the | |
842 | address should be interpreted (absolute, relative to the current | |
843 | position in the FDE, ...). Bit 7, indicates that the address | |
844 | should be dereferenced. */ | |
845 | ||
846 | static unsigned char | |
847 | encoding_for_size (unsigned int size) | |
848 | { | |
849 | switch (size) | |
850 | { | |
851 | case 2: | |
852 | return DW_EH_PE_udata2; | |
853 | case 4: | |
854 | return DW_EH_PE_udata4; | |
855 | case 8: | |
856 | return DW_EH_PE_udata8; | |
857 | default: | |
858 | internal_error (__FILE__, __LINE__, "Unsupported address size"); | |
859 | } | |
860 | } | |
861 | ||
862 | static unsigned int | |
863 | size_of_encoded_value (unsigned char encoding) | |
864 | { | |
865 | if (encoding == DW_EH_PE_omit) | |
866 | return 0; | |
867 | ||
868 | switch (encoding & 0x07) | |
869 | { | |
870 | case DW_EH_PE_absptr: | |
871 | return TYPE_LENGTH (builtin_type_void_data_ptr); | |
872 | case DW_EH_PE_udata2: | |
873 | return 2; | |
874 | case DW_EH_PE_udata4: | |
875 | return 4; | |
876 | case DW_EH_PE_udata8: | |
877 | return 8; | |
878 | default: | |
879 | internal_error (__FILE__, __LINE__, "Invalid or unsupported encoding"); | |
880 | } | |
881 | } | |
882 | ||
883 | static CORE_ADDR | |
884 | read_encoded_value (struct comp_unit *unit, unsigned char encoding, | |
885 | char *buf, unsigned int *bytes_read_ptr) | |
886 | { | |
887 | CORE_ADDR base; | |
888 | ||
889 | /* GCC currently doesn't generate DW_EH_PE_indirect encodings for | |
890 | FDE's. */ | |
891 | if (encoding & DW_EH_PE_indirect) | |
892 | internal_error (__FILE__, __LINE__, | |
893 | "Unsupported encoding: DW_EH_PE_indirect"); | |
894 | ||
895 | switch (encoding & 0x70) | |
896 | { | |
897 | case DW_EH_PE_absptr: | |
898 | base = 0; | |
899 | break; | |
900 | case DW_EH_PE_pcrel: | |
901 | base = bfd_get_section_vma (unit->bfd, unit->dwarf_frame_section); | |
902 | base += (buf - unit->dwarf_frame_buffer); | |
903 | break; | |
904 | default: | |
905 | internal_error (__FILE__, __LINE__, "Invalid or unsupported encoding"); | |
906 | } | |
907 | ||
908 | if ((encoding & 0x0f) == 0x00) | |
909 | encoding |= encoding_for_size (TYPE_LENGTH(builtin_type_void_data_ptr)); | |
910 | ||
911 | switch (encoding & 0x0f) | |
912 | { | |
913 | case DW_EH_PE_udata2: | |
914 | *bytes_read_ptr = 2; | |
915 | return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf)); | |
916 | case DW_EH_PE_udata4: | |
917 | *bytes_read_ptr = 4; | |
918 | return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf)); | |
919 | case DW_EH_PE_udata8: | |
920 | *bytes_read_ptr = 8; | |
921 | return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf)); | |
922 | case DW_EH_PE_sdata2: | |
923 | *bytes_read_ptr = 2; | |
924 | return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf)); | |
925 | case DW_EH_PE_sdata4: | |
926 | *bytes_read_ptr = 4; | |
927 | return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf)); | |
928 | case DW_EH_PE_sdata8: | |
929 | *bytes_read_ptr = 8; | |
930 | return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf)); | |
931 | default: | |
932 | internal_error (__FILE__, __LINE__, "Invalid or unsupported encoding"); | |
933 | } | |
934 | } | |
935 | \f | |
936 | ||
937 | /* GCC uses a single CIE for all FDEs in a .debug_frame section. | |
938 | That's why we use a simple linked list here. */ | |
939 | ||
940 | static struct dwarf2_cie * | |
941 | find_cie (struct comp_unit *unit, ULONGEST cie_pointer) | |
942 | { | |
943 | struct dwarf2_cie *cie = unit->cie; | |
944 | ||
945 | while (cie) | |
946 | { | |
947 | if (cie->cie_pointer == cie_pointer) | |
948 | return cie; | |
949 | ||
950 | cie = cie->next; | |
951 | } | |
952 | ||
953 | return NULL; | |
954 | } | |
955 | ||
956 | static void | |
957 | add_cie (struct comp_unit *unit, struct dwarf2_cie *cie) | |
958 | { | |
959 | cie->next = unit->cie; | |
960 | unit->cie = cie; | |
961 | } | |
962 | ||
963 | /* Find the FDE for *PC. Return a pointer to the FDE, and store the | |
964 | inital location associated with it into *PC. */ | |
965 | ||
966 | static struct dwarf2_fde * | |
967 | dwarf2_frame_find_fde (CORE_ADDR *pc) | |
968 | { | |
969 | struct objfile *objfile; | |
970 | ||
971 | ALL_OBJFILES (objfile) | |
972 | { | |
973 | struct dwarf2_fde *fde; | |
974 | CORE_ADDR offset; | |
975 | ||
976 | offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile)); | |
977 | ||
978 | fde = objfile->sym_private; | |
979 | while (fde) | |
980 | { | |
981 | if (*pc >= fde->initial_location + offset | |
982 | && *pc < fde->initial_location + offset + fde->address_range) | |
983 | { | |
984 | *pc = fde->initial_location + offset; | |
985 | return fde; | |
986 | } | |
987 | ||
988 | fde = fde->next; | |
989 | } | |
990 | } | |
991 | ||
992 | return NULL; | |
993 | } | |
994 | ||
995 | static void | |
996 | add_fde (struct comp_unit *unit, struct dwarf2_fde *fde) | |
997 | { | |
998 | fde->next = unit->objfile->sym_private; | |
999 | unit->objfile->sym_private = fde; | |
1000 | } | |
1001 | ||
1002 | #ifdef CC_HAS_LONG_LONG | |
1003 | #define DW64_CIE_ID 0xffffffffffffffffULL | |
1004 | #else | |
1005 | #define DW64_CIE_ID ~0 | |
1006 | #endif | |
1007 | ||
1008 | /* Read a CIE or FDE in BUF and decode it. */ | |
1009 | ||
1010 | static char * | |
1011 | decode_frame_entry (struct comp_unit *unit, char *buf, int eh_frame_p) | |
1012 | { | |
1013 | LONGEST length; | |
1014 | unsigned int bytes_read; | |
1015 | int dwarf64_p = 0; | |
1016 | ULONGEST cie_id = DW_CIE_ID; | |
1017 | ULONGEST cie_pointer; | |
1018 | char *start = buf; | |
1019 | char *end; | |
1020 | ||
1021 | length = read_initial_length (unit->abfd, buf, &bytes_read); | |
1022 | buf += bytes_read; | |
1023 | end = buf + length; | |
1024 | ||
1025 | if (length == 0) | |
1026 | return end; | |
1027 | ||
1028 | if (bytes_read == 12) | |
1029 | dwarf64_p = 1; | |
1030 | ||
1031 | /* In a .eh_frame section, zero is used to distinguish CIEs from | |
1032 | FDEs. */ | |
1033 | if (eh_frame_p) | |
1034 | cie_id = 0; | |
1035 | else if (dwarf64_p) | |
1036 | cie_id = DW64_CIE_ID; | |
1037 | ||
1038 | if (dwarf64_p) | |
1039 | { | |
1040 | cie_pointer = read_8_bytes (unit->abfd, buf); | |
1041 | buf += 8; | |
1042 | } | |
1043 | else | |
1044 | { | |
1045 | cie_pointer = read_4_bytes (unit->abfd, buf); | |
1046 | buf += 4; | |
1047 | } | |
1048 | ||
1049 | if (cie_pointer == cie_id) | |
1050 | { | |
1051 | /* This is a CIE. */ | |
1052 | struct dwarf2_cie *cie; | |
1053 | char *augmentation; | |
1054 | ||
1055 | /* Record the offset into the .debug_frame section of this CIE. */ | |
1056 | cie_pointer = start - unit->dwarf_frame_buffer; | |
1057 | ||
1058 | /* Check whether we've already read it. */ | |
1059 | if (find_cie (unit, cie_pointer)) | |
1060 | return end; | |
1061 | ||
1062 | cie = (struct dwarf2_cie *) | |
1063 | obstack_alloc (&unit->objfile->psymbol_obstack, | |
1064 | sizeof (struct dwarf2_cie)); | |
1065 | cie->initial_instructions = NULL; | |
1066 | cie->cie_pointer = cie_pointer; | |
1067 | ||
1068 | /* The encoding for FDE's in a normal .debug_frame section | |
1069 | depends on the target address size as specified in the | |
1070 | Compilation Unit Header. */ | |
1071 | cie->encoding = encoding_for_size (unit->addr_size); | |
1072 | ||
1073 | /* Check version number. */ | |
1074 | gdb_assert (read_1_byte (unit->abfd, buf) == DW_CIE_VERSION); | |
1075 | buf += 1; | |
1076 | ||
1077 | /* Interpret the interesting bits of the augmentation. */ | |
1078 | augmentation = buf; | |
1079 | buf = augmentation + strlen (augmentation) + 1; | |
1080 | ||
1081 | /* The GCC 2.x "eh" augmentation has a pointer immediately | |
1082 | following the augmentation string, so it must be handled | |
1083 | first. */ | |
1084 | if (augmentation[0] == 'e' && augmentation[1] == 'h') | |
1085 | { | |
1086 | /* Skip. */ | |
1087 | buf += TYPE_LENGTH (builtin_type_void_data_ptr); | |
1088 | augmentation += 2; | |
1089 | } | |
1090 | ||
1091 | cie->code_alignment_factor = | |
1092 | read_unsigned_leb128 (unit->abfd, buf, &bytes_read); | |
1093 | buf += bytes_read; | |
1094 | ||
1095 | cie->data_alignment_factor = | |
1096 | read_signed_leb128 (unit->abfd, buf, &bytes_read); | |
1097 | buf += bytes_read; | |
1098 | ||
1099 | cie->return_address_register = read_1_byte (unit->abfd, buf); | |
1100 | buf += 1; | |
1101 | ||
1102 | if (*augmentation == 'z') | |
1103 | { | |
1104 | ULONGEST length; | |
1105 | ||
1106 | length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read); | |
1107 | buf += bytes_read; | |
1108 | cie->initial_instructions = buf + length; | |
1109 | augmentation++; | |
1110 | } | |
1111 | ||
1112 | while (*augmentation) | |
1113 | { | |
1114 | /* "L" indicates a byte showing how the LSDA pointer is encoded. */ | |
1115 | if (*augmentation == 'L') | |
1116 | { | |
1117 | /* Skip. */ | |
1118 | buf++; | |
1119 | augmentation++; | |
1120 | } | |
1121 | ||
1122 | /* "R" indicates a byte indicating how FDE addresses are encoded. */ | |
1123 | else if (*augmentation == 'R') | |
1124 | { | |
1125 | cie->encoding = *buf++; | |
1126 | augmentation++; | |
1127 | } | |
1128 | ||
1129 | /* "P" indicates a personality routine in the CIE augmentation. */ | |
1130 | else if (*augmentation == 'P') | |
1131 | { | |
1132 | /* Skip. */ | |
1133 | buf += size_of_encoded_value (*buf++); | |
1134 | augmentation++; | |
1135 | } | |
1136 | ||
1137 | /* Otherwise we have an unknown augmentation. | |
1138 | Bail out unless we saw a 'z' prefix. */ | |
1139 | else | |
1140 | { | |
1141 | if (cie->initial_instructions == NULL) | |
1142 | return end; | |
1143 | ||
1144 | /* Skip unknown augmentations. */ | |
1145 | buf = cie->initial_instructions; | |
1146 | break; | |
1147 | } | |
1148 | } | |
1149 | ||
1150 | cie->initial_instructions = buf; | |
1151 | cie->end = end; | |
1152 | ||
1153 | add_cie (unit, cie); | |
1154 | } | |
1155 | else | |
1156 | { | |
1157 | /* This is a FDE. */ | |
1158 | struct dwarf2_fde *fde; | |
1159 | ||
1160 | if (eh_frame_p) | |
1161 | { | |
1162 | /* In an .eh_frame section, the CIE pointer is the delta | |
1163 | between the address within the FDE where the CIE pointer | |
1164 | is stored and the address of the CIE. Convert it to an | |
1165 | offset into the .eh_frame section. */ | |
1166 | cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer; | |
1167 | cie_pointer -= (dwarf64_p ? 8 : 4); | |
1168 | } | |
1169 | ||
1170 | fde = (struct dwarf2_fde *) | |
1171 | obstack_alloc (&unit->objfile->psymbol_obstack, | |
1172 | sizeof (struct dwarf2_fde)); | |
1173 | fde->cie = find_cie (unit, cie_pointer); | |
1174 | if (fde->cie == NULL) | |
1175 | { | |
1176 | decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer, | |
1177 | eh_frame_p); | |
1178 | fde->cie = find_cie (unit, cie_pointer); | |
1179 | } | |
1180 | ||
1181 | gdb_assert (fde->cie != NULL); | |
1182 | ||
1183 | fde->initial_location = | |
1184 | read_encoded_value (unit, fde->cie->encoding, buf, &bytes_read); | |
1185 | buf += bytes_read; | |
1186 | ||
1187 | fde->address_range = | |
1188 | read_encoded_value (unit, fde->cie->encoding & 0x0f, buf, &bytes_read); | |
1189 | buf += bytes_read; | |
1190 | ||
1191 | fde->instructions = buf; | |
1192 | fde->end = end; | |
1193 | ||
1194 | add_fde (unit, fde); | |
1195 | } | |
1196 | ||
1197 | return end; | |
1198 | } | |
1199 | \f | |
1200 | ||
1201 | /* FIXME: kettenis/20030504: This still needs to be integrated with | |
1202 | dwarf2read.c in a better way. */ | |
1203 | ||
1204 | /* Imported from dwarf2read.c. */ | |
1205 | extern file_ptr dwarf_frame_offset; | |
1206 | extern unsigned int dwarf_frame_size; | |
1207 | extern asection *dwarf_frame_section; | |
1208 | extern file_ptr dwarf_eh_frame_offset; | |
1209 | extern unsigned int dwarf_eh_frame_size; | |
1210 | extern asection *dwarf_eh_frame_section; | |
1211 | ||
1212 | /* Imported from dwarf2read.c. */ | |
1213 | extern char *dwarf2_read_section (struct objfile *objfile, file_ptr offset, | |
1214 | unsigned int size, asection *sectp); | |
1215 | ||
1216 | void | |
1217 | dwarf2_build_frame_info (struct objfile *objfile) | |
1218 | { | |
1219 | struct comp_unit unit; | |
1220 | char *frame_ptr; | |
1221 | ||
1222 | /* Build a minimal decoding of the DWARF2 compilation unit. */ | |
1223 | unit.abfd = objfile->obfd; | |
1224 | unit.objfile = objfile; | |
1225 | unit.addr_size = objfile->obfd->arch_info->bits_per_address / 8; | |
1226 | ||
1227 | /* First add the information from the .eh_frame section. That way, | |
1228 | the FDEs from that section are searched last. */ | |
1229 | if (dwarf_eh_frame_offset) | |
1230 | { | |
1231 | unit.cie = NULL; | |
1232 | unit.dwarf_frame_buffer = dwarf2_read_section (objfile, | |
1233 | dwarf_eh_frame_offset, | |
1234 | dwarf_eh_frame_size, | |
1235 | dwarf_eh_frame_section); | |
1236 | ||
1237 | unit.dwarf_frame_size = dwarf_eh_frame_size; | |
1238 | unit.dwarf_frame_section = dwarf_eh_frame_section; | |
1239 | ||
1240 | frame_ptr = unit.dwarf_frame_buffer; | |
1241 | while (frame_ptr < unit.dwarf_frame_buffer + unit.dwarf_frame_size) | |
1242 | frame_ptr = decode_frame_entry (&unit, frame_ptr, 1); | |
1243 | } | |
1244 | ||
1245 | if (dwarf_frame_offset) | |
1246 | { | |
1247 | unit.cie = NULL; | |
1248 | unit.dwarf_frame_buffer = dwarf2_read_section (objfile, | |
1249 | dwarf_frame_offset, | |
1250 | dwarf_frame_size, | |
1251 | dwarf_frame_section); | |
1252 | unit.dwarf_frame_size = dwarf_frame_size; | |
1253 | unit.dwarf_frame_section = dwarf_frame_section; | |
1254 | ||
1255 | frame_ptr = unit.dwarf_frame_buffer; | |
1256 | while (frame_ptr < unit.dwarf_frame_buffer + unit.dwarf_frame_size) | |
1257 | frame_ptr = decode_frame_entry (&unit, frame_ptr, 0); | |
1258 | } | |
1259 | } |