Upgrade GDB from 7.4.1 to 7.6.1 on the vendor branch
[dragonfly.git] / contrib / gdb-7 / gdb / dwarf2-frame.c
CommitLineData
5796c8dc
SS
1/* Frame unwinder for frames with DWARF Call Frame Information.
2
ef5ccd6c 3 Copyright (C) 2003-2013 Free Software Foundation, Inc.
5796c8dc
SS
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 3 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, see <http://www.gnu.org/licenses/>. */
21
22#include "defs.h"
23#include "dwarf2expr.h"
24#include "dwarf2.h"
25#include "frame.h"
26#include "frame-base.h"
27#include "frame-unwind.h"
28#include "gdbcore.h"
29#include "gdbtypes.h"
30#include "symtab.h"
31#include "objfiles.h"
32#include "regcache.h"
33#include "value.h"
34
35#include "gdb_assert.h"
36#include "gdb_string.h"
37
38#include "complaints.h"
39#include "dwarf2-frame.h"
c50c785c
JM
40#include "ax.h"
41#include "dwarf2loc.h"
42#include "exceptions.h"
a45ae5f8 43#include "dwarf2-frame-tailcall.h"
5796c8dc
SS
44
45struct comp_unit;
46
47/* Call Frame Information (CFI). */
48
49/* Common Information Entry (CIE). */
50
51struct dwarf2_cie
52{
53 /* Computation Unit for this CIE. */
54 struct comp_unit *unit;
55
56 /* Offset into the .debug_frame section where this CIE was found.
57 Used to identify this CIE. */
58 ULONGEST cie_pointer;
59
60 /* Constant that is factored out of all advance location
61 instructions. */
62 ULONGEST code_alignment_factor;
63
64 /* Constants that is factored out of all offset instructions. */
65 LONGEST data_alignment_factor;
66
67 /* Return address column. */
68 ULONGEST return_address_register;
69
70 /* Instruction sequence to initialize a register set. */
ef5ccd6c
JM
71 const gdb_byte *initial_instructions;
72 const gdb_byte *end;
5796c8dc
SS
73
74 /* Saved augmentation, in case it's needed later. */
75 char *augmentation;
76
77 /* Encoding of addresses. */
78 gdb_byte encoding;
79
80 /* Target address size in bytes. */
81 int addr_size;
82
c50c785c
JM
83 /* Target pointer size in bytes. */
84 int ptr_size;
85
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SS
86 /* True if a 'z' augmentation existed. */
87 unsigned char saw_z_augmentation;
88
89 /* True if an 'S' augmentation existed. */
90 unsigned char signal_frame;
91
92 /* The version recorded in the CIE. */
93 unsigned char version;
cf7f2e2d
JM
94
95 /* The segment size. */
96 unsigned char segment_size;
5796c8dc
SS
97};
98
99struct dwarf2_cie_table
100{
101 int num_entries;
102 struct dwarf2_cie **entries;
103};
104
105/* Frame Description Entry (FDE). */
106
107struct dwarf2_fde
108{
109 /* CIE for this FDE. */
110 struct dwarf2_cie *cie;
111
112 /* First location associated with this FDE. */
113 CORE_ADDR initial_location;
114
115 /* Number of bytes of program instructions described by this FDE. */
116 CORE_ADDR address_range;
117
118 /* Instruction sequence. */
ef5ccd6c
JM
119 const gdb_byte *instructions;
120 const gdb_byte *end;
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SS
121
122 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
123 section. */
124 unsigned char eh_frame_p;
125};
126
127struct dwarf2_fde_table
128{
129 int num_entries;
130 struct dwarf2_fde **entries;
131};
132
133/* A minimal decoding of DWARF2 compilation units. We only decode
134 what's needed to get to the call frame information. */
135
136struct comp_unit
137{
138 /* Keep the bfd convenient. */
139 bfd *abfd;
140
141 struct objfile *objfile;
142
143 /* Pointer to the .debug_frame section loaded into memory. */
144 gdb_byte *dwarf_frame_buffer;
145
146 /* Length of the loaded .debug_frame section. */
147 bfd_size_type dwarf_frame_size;
148
149 /* Pointer to the .debug_frame section. */
150 asection *dwarf_frame_section;
151
152 /* Base for DW_EH_PE_datarel encodings. */
153 bfd_vma dbase;
154
155 /* Base for DW_EH_PE_textrel encodings. */
156 bfd_vma tbase;
157};
158
cf7f2e2d
JM
159static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc,
160 CORE_ADDR *out_offset);
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SS
161
162static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum,
163 int eh_frame_p);
164
165static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
cf7f2e2d 166 int ptr_len, const gdb_byte *buf,
5796c8dc
SS
167 unsigned int *bytes_read_ptr,
168 CORE_ADDR func_base);
169\f
170
171/* Structure describing a frame state. */
172
173struct dwarf2_frame_state
174{
175 /* Each register save state can be described in terms of a CFA slot,
176 another register, or a location expression. */
177 struct dwarf2_frame_state_reg_info
178 {
179 struct dwarf2_frame_state_reg *reg;
180 int num_regs;
181
182 LONGEST cfa_offset;
183 ULONGEST cfa_reg;
184 enum {
185 CFA_UNSET,
186 CFA_REG_OFFSET,
187 CFA_EXP
188 } cfa_how;
cf7f2e2d 189 const gdb_byte *cfa_exp;
5796c8dc
SS
190
191 /* Used to implement DW_CFA_remember_state. */
192 struct dwarf2_frame_state_reg_info *prev;
193 } regs;
194
195 /* The PC described by the current frame state. */
196 CORE_ADDR pc;
197
198 /* Initial register set from the CIE.
199 Used to implement DW_CFA_restore. */
200 struct dwarf2_frame_state_reg_info initial;
201
202 /* The information we care about from the CIE. */
203 LONGEST data_align;
204 ULONGEST code_align;
205 ULONGEST retaddr_column;
206
207 /* Flags for known producer quirks. */
208
209 /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa
210 and DW_CFA_def_cfa_offset takes a factored offset. */
211 int armcc_cfa_offsets_sf;
212
213 /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
214 the CFA is defined as REG - OFFSET rather than REG + OFFSET. */
215 int armcc_cfa_offsets_reversed;
216};
217
218/* Store the length the expression for the CFA in the `cfa_reg' field,
219 which is unused in that case. */
220#define cfa_exp_len cfa_reg
221
222/* Assert that the register set RS is large enough to store gdbarch_num_regs
223 columns. If necessary, enlarge the register set. */
224
225static void
226dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs,
227 int num_regs)
228{
229 size_t size = sizeof (struct dwarf2_frame_state_reg);
230
231 if (num_regs <= rs->num_regs)
232 return;
233
234 rs->reg = (struct dwarf2_frame_state_reg *)
235 xrealloc (rs->reg, num_regs * size);
236
237 /* Initialize newly allocated registers. */
238 memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size);
239 rs->num_regs = num_regs;
240}
241
242/* Copy the register columns in register set RS into newly allocated
243 memory and return a pointer to this newly created copy. */
244
245static struct dwarf2_frame_state_reg *
246dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs)
247{
248 size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg);
249 struct dwarf2_frame_state_reg *reg;
250
251 reg = (struct dwarf2_frame_state_reg *) xmalloc (size);
252 memcpy (reg, rs->reg, size);
253
254 return reg;
255}
256
257/* Release the memory allocated to register set RS. */
258
259static void
260dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs)
261{
262 if (rs)
263 {
264 dwarf2_frame_state_free_regs (rs->prev);
265
266 xfree (rs->reg);
267 xfree (rs);
268 }
269}
270
271/* Release the memory allocated to the frame state FS. */
272
273static void
274dwarf2_frame_state_free (void *p)
275{
276 struct dwarf2_frame_state *fs = p;
277
278 dwarf2_frame_state_free_regs (fs->initial.prev);
279 dwarf2_frame_state_free_regs (fs->regs.prev);
280 xfree (fs->initial.reg);
281 xfree (fs->regs.reg);
282 xfree (fs);
283}
284\f
285
286/* Helper functions for execute_stack_op. */
287
288static CORE_ADDR
289read_reg (void *baton, int reg)
290{
291 struct frame_info *this_frame = (struct frame_info *) baton;
292 struct gdbarch *gdbarch = get_frame_arch (this_frame);
293 int regnum;
294 gdb_byte *buf;
295
296 regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
297
298 buf = alloca (register_size (gdbarch, regnum));
299 get_frame_register (this_frame, regnum, buf);
300
301 /* Convert the register to an integer. This returns a LONGEST
302 rather than a CORE_ADDR, but unpack_pointer does the same thing
303 under the covers, and this makes more sense for non-pointer
304 registers. Maybe read_reg and the associated interfaces should
305 deal with "struct value" instead of CORE_ADDR. */
306 return unpack_long (register_type (gdbarch, regnum), buf);
307}
308
309static void
310read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
311{
312 read_memory (addr, buf, len);
313}
314
5796c8dc
SS
315/* Execute the required actions for both the DW_CFA_restore and
316DW_CFA_restore_extended instructions. */
317static void
318dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
319 struct dwarf2_frame_state *fs, int eh_frame_p)
320{
321 ULONGEST reg;
322
323 gdb_assert (fs->initial.reg);
324 reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
325 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
326
327 /* Check if this register was explicitly initialized in the
328 CIE initial instructions. If not, default the rule to
329 UNSPECIFIED. */
330 if (reg < fs->initial.num_regs)
331 fs->regs.reg[reg] = fs->initial.reg[reg];
332 else
333 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;
334
335 if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED)
336 complaint (&symfile_complaints, _("\
337incomplete CFI data; DW_CFA_restore unspecified\n\
338register %s (#%d) at %s"),
339 gdbarch_register_name
340 (gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)),
341 gdbarch_dwarf2_reg_to_regnum (gdbarch, reg),
342 paddress (gdbarch, fs->pc));
343}
344
a45ae5f8
JM
345/* Virtual method table for execute_stack_op below. */
346
347static const struct dwarf_expr_context_funcs dwarf2_frame_ctx_funcs =
348{
349 read_reg,
350 read_mem,
351 ctx_no_get_frame_base,
352 ctx_no_get_frame_cfa,
353 ctx_no_get_frame_pc,
354 ctx_no_get_tls_address,
355 ctx_no_dwarf_call,
356 ctx_no_get_base_type,
ef5ccd6c
JM
357 ctx_no_push_dwarf_reg_entry_value,
358 ctx_no_get_addr_index
a45ae5f8
JM
359};
360
5796c8dc 361static CORE_ADDR
cf7f2e2d
JM
362execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
363 CORE_ADDR offset, struct frame_info *this_frame,
364 CORE_ADDR initial, int initial_in_stack_memory)
5796c8dc
SS
365{
366 struct dwarf_expr_context *ctx;
367 CORE_ADDR result;
368 struct cleanup *old_chain;
369
370 ctx = new_dwarf_expr_context ();
371 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
a45ae5f8 372 make_cleanup_value_free_to_mark (value_mark ());
5796c8dc
SS
373
374 ctx->gdbarch = get_frame_arch (this_frame);
375 ctx->addr_size = addr_size;
a45ae5f8 376 ctx->ref_addr_size = -1;
cf7f2e2d 377 ctx->offset = offset;
5796c8dc 378 ctx->baton = this_frame;
a45ae5f8
JM
379 ctx->funcs = &dwarf2_frame_ctx_funcs;
380
381 dwarf_expr_push_address (ctx, initial, initial_in_stack_memory);
5796c8dc 382 dwarf_expr_eval (ctx, exp, len);
5796c8dc 383
cf7f2e2d
JM
384 if (ctx->location == DWARF_VALUE_MEMORY)
385 result = dwarf_expr_fetch_address (ctx, 0);
386 else if (ctx->location == DWARF_VALUE_REGISTER)
a45ae5f8 387 result = read_reg (this_frame, value_as_long (dwarf_expr_fetch (ctx, 0)));
cf7f2e2d 388 else
5796c8dc
SS
389 {
390 /* This is actually invalid DWARF, but if we ever do run across
391 it somehow, we might as well support it. So, instead, report
392 it as unimplemented. */
c50c785c
JM
393 error (_("\
394Not implemented: computing unwound register using explicit value operator"));
5796c8dc
SS
395 }
396
397 do_cleanups (old_chain);
398
399 return result;
400}
401\f
402
a45ae5f8
JM
403/* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior
404 PC. Modify FS state accordingly. Return current INSN_PTR where the
405 execution has stopped, one can resume it on the next call. */
406
407static const gdb_byte *
cf7f2e2d 408execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,
c50c785c
JM
409 const gdb_byte *insn_end, struct gdbarch *gdbarch,
410 CORE_ADDR pc, struct dwarf2_frame_state *fs)
5796c8dc
SS
411{
412 int eh_frame_p = fde->eh_frame_p;
5796c8dc 413 int bytes_read;
5796c8dc
SS
414 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
415
416 while (insn_ptr < insn_end && fs->pc <= pc)
417 {
418 gdb_byte insn = *insn_ptr++;
ef5ccd6c
JM
419 uint64_t utmp, reg;
420 int64_t offset;
5796c8dc
SS
421
422 if ((insn & 0xc0) == DW_CFA_advance_loc)
423 fs->pc += (insn & 0x3f) * fs->code_align;
424 else if ((insn & 0xc0) == DW_CFA_offset)
425 {
426 reg = insn & 0x3f;
427 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
ef5ccd6c 428 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
5796c8dc
SS
429 offset = utmp * fs->data_align;
430 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
431 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
432 fs->regs.reg[reg].loc.offset = offset;
433 }
434 else if ((insn & 0xc0) == DW_CFA_restore)
435 {
436 reg = insn & 0x3f;
437 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
438 }
439 else
440 {
441 switch (insn)
442 {
443 case DW_CFA_set_loc:
444 fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
c50c785c 445 fde->cie->ptr_size, insn_ptr,
5796c8dc
SS
446 &bytes_read, fde->initial_location);
447 /* Apply the objfile offset for relocatable objects. */
448 fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets,
449 SECT_OFF_TEXT (fde->cie->unit->objfile));
450 insn_ptr += bytes_read;
451 break;
452
453 case DW_CFA_advance_loc1:
454 utmp = extract_unsigned_integer (insn_ptr, 1, byte_order);
455 fs->pc += utmp * fs->code_align;
456 insn_ptr++;
457 break;
458 case DW_CFA_advance_loc2:
459 utmp = extract_unsigned_integer (insn_ptr, 2, byte_order);
460 fs->pc += utmp * fs->code_align;
461 insn_ptr += 2;
462 break;
463 case DW_CFA_advance_loc4:
464 utmp = extract_unsigned_integer (insn_ptr, 4, byte_order);
465 fs->pc += utmp * fs->code_align;
466 insn_ptr += 4;
467 break;
468
469 case DW_CFA_offset_extended:
ef5ccd6c 470 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
5796c8dc 471 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
ef5ccd6c 472 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
5796c8dc
SS
473 offset = utmp * fs->data_align;
474 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
475 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
476 fs->regs.reg[reg].loc.offset = offset;
477 break;
478
479 case DW_CFA_restore_extended:
ef5ccd6c 480 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
5796c8dc
SS
481 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
482 break;
483
484 case DW_CFA_undefined:
ef5ccd6c 485 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
5796c8dc
SS
486 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
487 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
488 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
489 break;
490
491 case DW_CFA_same_value:
ef5ccd6c 492 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
5796c8dc
SS
493 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
494 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
495 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE;
496 break;
497
498 case DW_CFA_register:
ef5ccd6c 499 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
5796c8dc 500 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
ef5ccd6c 501 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
5796c8dc
SS
502 utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p);
503 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
504 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
505 fs->regs.reg[reg].loc.reg = utmp;
506 break;
507
508 case DW_CFA_remember_state:
509 {
510 struct dwarf2_frame_state_reg_info *new_rs;
511
512 new_rs = XMALLOC (struct dwarf2_frame_state_reg_info);
513 *new_rs = fs->regs;
514 fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs);
515 fs->regs.prev = new_rs;
516 }
517 break;
518
519 case DW_CFA_restore_state:
520 {
521 struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;
522
523 if (old_rs == NULL)
524 {
525 complaint (&symfile_complaints, _("\
526bad CFI data; mismatched DW_CFA_restore_state at %s"),
527 paddress (gdbarch, fs->pc));
528 }
529 else
530 {
531 xfree (fs->regs.reg);
532 fs->regs = *old_rs;
533 xfree (old_rs);
534 }
535 }
536 break;
537
538 case DW_CFA_def_cfa:
ef5ccd6c
JM
539 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
540 fs->regs.cfa_reg = reg;
541 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
5796c8dc
SS
542
543 if (fs->armcc_cfa_offsets_sf)
544 utmp *= fs->data_align;
545
546 fs->regs.cfa_offset = utmp;
547 fs->regs.cfa_how = CFA_REG_OFFSET;
548 break;
549
550 case DW_CFA_def_cfa_register:
ef5ccd6c
JM
551 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
552 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
5796c8dc
SS
553 eh_frame_p);
554 fs->regs.cfa_how = CFA_REG_OFFSET;
555 break;
556
557 case DW_CFA_def_cfa_offset:
ef5ccd6c 558 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
5796c8dc
SS
559
560 if (fs->armcc_cfa_offsets_sf)
561 utmp *= fs->data_align;
562
563 fs->regs.cfa_offset = utmp;
564 /* cfa_how deliberately not set. */
565 break;
566
567 case DW_CFA_nop:
568 break;
569
570 case DW_CFA_def_cfa_expression:
ef5ccd6c
JM
571 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
572 fs->regs.cfa_exp_len = utmp;
5796c8dc
SS
573 fs->regs.cfa_exp = insn_ptr;
574 fs->regs.cfa_how = CFA_EXP;
575 insn_ptr += fs->regs.cfa_exp_len;
576 break;
577
578 case DW_CFA_expression:
ef5ccd6c 579 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
5796c8dc
SS
580 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
581 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
ef5ccd6c 582 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
5796c8dc
SS
583 fs->regs.reg[reg].loc.exp = insn_ptr;
584 fs->regs.reg[reg].exp_len = utmp;
585 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
586 insn_ptr += utmp;
587 break;
588
589 case DW_CFA_offset_extended_sf:
ef5ccd6c 590 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
5796c8dc 591 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
ef5ccd6c 592 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
5796c8dc
SS
593 offset *= fs->data_align;
594 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
595 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
596 fs->regs.reg[reg].loc.offset = offset;
597 break;
598
599 case DW_CFA_val_offset:
ef5ccd6c 600 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
5796c8dc 601 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
ef5ccd6c 602 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
5796c8dc
SS
603 offset = utmp * fs->data_align;
604 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
605 fs->regs.reg[reg].loc.offset = offset;
606 break;
607
608 case DW_CFA_val_offset_sf:
ef5ccd6c 609 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
5796c8dc 610 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
ef5ccd6c 611 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
5796c8dc
SS
612 offset *= fs->data_align;
613 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
614 fs->regs.reg[reg].loc.offset = offset;
615 break;
616
617 case DW_CFA_val_expression:
ef5ccd6c 618 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
5796c8dc 619 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
ef5ccd6c 620 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
5796c8dc
SS
621 fs->regs.reg[reg].loc.exp = insn_ptr;
622 fs->regs.reg[reg].exp_len = utmp;
623 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP;
624 insn_ptr += utmp;
625 break;
626
627 case DW_CFA_def_cfa_sf:
ef5ccd6c
JM
628 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
629 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
5796c8dc 630 eh_frame_p);
ef5ccd6c 631 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
5796c8dc
SS
632 fs->regs.cfa_offset = offset * fs->data_align;
633 fs->regs.cfa_how = CFA_REG_OFFSET;
634 break;
635
636 case DW_CFA_def_cfa_offset_sf:
ef5ccd6c 637 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
5796c8dc
SS
638 fs->regs.cfa_offset = offset * fs->data_align;
639 /* cfa_how deliberately not set. */
640 break;
641
642 case DW_CFA_GNU_window_save:
643 /* This is SPARC-specific code, and contains hard-coded
644 constants for the register numbering scheme used by
645 GCC. Rather than having a architecture-specific
646 operation that's only ever used by a single
647 architecture, we provide the implementation here.
648 Incidentally that's what GCC does too in its
649 unwinder. */
650 {
651 int size = register_size (gdbarch, 0);
cf7f2e2d 652
5796c8dc
SS
653 dwarf2_frame_state_alloc_regs (&fs->regs, 32);
654 for (reg = 8; reg < 16; reg++)
655 {
656 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
657 fs->regs.reg[reg].loc.reg = reg + 16;
658 }
659 for (reg = 16; reg < 32; reg++)
660 {
661 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
662 fs->regs.reg[reg].loc.offset = (reg - 16) * size;
663 }
664 }
665 break;
666
667 case DW_CFA_GNU_args_size:
668 /* Ignored. */
ef5ccd6c 669 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
5796c8dc
SS
670 break;
671
672 case DW_CFA_GNU_negative_offset_extended:
ef5ccd6c 673 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &reg);
5796c8dc 674 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
ef5ccd6c 675 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &offset);
5796c8dc
SS
676 offset *= fs->data_align;
677 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
678 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
679 fs->regs.reg[reg].loc.offset = -offset;
680 break;
681
682 default:
c50c785c
JM
683 internal_error (__FILE__, __LINE__,
684 _("Unknown CFI encountered."));
5796c8dc
SS
685 }
686 }
687 }
688
a45ae5f8
JM
689 if (fs->initial.reg == NULL)
690 {
691 /* Don't allow remember/restore between CIE and FDE programs. */
692 dwarf2_frame_state_free_regs (fs->regs.prev);
693 fs->regs.prev = NULL;
694 }
695
696 return insn_ptr;
5796c8dc
SS
697}
698\f
699
700/* Architecture-specific operations. */
701
702/* Per-architecture data key. */
703static struct gdbarch_data *dwarf2_frame_data;
704
705struct dwarf2_frame_ops
706{
707 /* Pre-initialize the register state REG for register REGNUM. */
708 void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *,
709 struct frame_info *);
710
711 /* Check whether the THIS_FRAME is a signal trampoline. */
712 int (*signal_frame_p) (struct gdbarch *, struct frame_info *);
713
714 /* Convert .eh_frame register number to DWARF register number, or
715 adjust .debug_frame register number. */
716 int (*adjust_regnum) (struct gdbarch *, int, int);
717};
718
719/* Default architecture-specific register state initialization
720 function. */
721
722static void
723dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
724 struct dwarf2_frame_state_reg *reg,
725 struct frame_info *this_frame)
726{
727 /* If we have a register that acts as a program counter, mark it as
728 a destination for the return address. If we have a register that
729 serves as the stack pointer, arrange for it to be filled with the
730 call frame address (CFA). The other registers are marked as
731 unspecified.
732
733 We copy the return address to the program counter, since many
734 parts in GDB assume that it is possible to get the return address
735 by unwinding the program counter register. However, on ISA's
736 with a dedicated return address register, the CFI usually only
737 contains information to unwind that return address register.
738
739 The reason we're treating the stack pointer special here is
740 because in many cases GCC doesn't emit CFI for the stack pointer
741 and implicitly assumes that it is equal to the CFA. This makes
742 some sense since the DWARF specification (version 3, draft 8,
743 p. 102) says that:
744
745 "Typically, the CFA is defined to be the value of the stack
746 pointer at the call site in the previous frame (which may be
747 different from its value on entry to the current frame)."
748
749 However, this isn't true for all platforms supported by GCC
750 (e.g. IBM S/390 and zSeries). Those architectures should provide
751 their own architecture-specific initialization function. */
752
753 if (regnum == gdbarch_pc_regnum (gdbarch))
754 reg->how = DWARF2_FRAME_REG_RA;
755 else if (regnum == gdbarch_sp_regnum (gdbarch))
756 reg->how = DWARF2_FRAME_REG_CFA;
757}
758
759/* Return a default for the architecture-specific operations. */
760
761static void *
762dwarf2_frame_init (struct obstack *obstack)
763{
764 struct dwarf2_frame_ops *ops;
765
766 ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
767 ops->init_reg = dwarf2_frame_default_init_reg;
768 return ops;
769}
770
771/* Set the architecture-specific register state initialization
772 function for GDBARCH to INIT_REG. */
773
774void
775dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
776 void (*init_reg) (struct gdbarch *, int,
777 struct dwarf2_frame_state_reg *,
778 struct frame_info *))
779{
780 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
781
782 ops->init_reg = init_reg;
783}
784
785/* Pre-initialize the register state REG for register REGNUM. */
786
787static void
788dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
789 struct dwarf2_frame_state_reg *reg,
790 struct frame_info *this_frame)
791{
792 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
793
794 ops->init_reg (gdbarch, regnum, reg, this_frame);
795}
796
797/* Set the architecture-specific signal trampoline recognition
798 function for GDBARCH to SIGNAL_FRAME_P. */
799
800void
801dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
802 int (*signal_frame_p) (struct gdbarch *,
803 struct frame_info *))
804{
805 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
806
807 ops->signal_frame_p = signal_frame_p;
808}
809
810/* Query the architecture-specific signal frame recognizer for
811 THIS_FRAME. */
812
813static int
814dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
815 struct frame_info *this_frame)
816{
817 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
818
819 if (ops->signal_frame_p == NULL)
820 return 0;
821 return ops->signal_frame_p (gdbarch, this_frame);
822}
823
824/* Set the architecture-specific adjustment of .eh_frame and .debug_frame
825 register numbers. */
826
827void
828dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
829 int (*adjust_regnum) (struct gdbarch *,
830 int, int))
831{
832 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
833
834 ops->adjust_regnum = adjust_regnum;
835}
836
837/* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
838 register. */
839
840static int
c50c785c
JM
841dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch,
842 int regnum, int eh_frame_p)
5796c8dc
SS
843{
844 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
845
846 if (ops->adjust_regnum == NULL)
847 return regnum;
848 return ops->adjust_regnum (gdbarch, regnum, eh_frame_p);
849}
850
851static void
852dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
853 struct dwarf2_fde *fde)
854{
5796c8dc
SS
855 struct symtab *s;
856
857 s = find_pc_symtab (fs->pc);
cf7f2e2d 858 if (s == NULL)
5796c8dc
SS
859 return;
860
cf7f2e2d
JM
861 if (producer_is_realview (s->producer))
862 {
863 if (fde->cie->version == 1)
864 fs->armcc_cfa_offsets_sf = 1;
865
866 if (fde->cie->version == 1)
867 fs->armcc_cfa_offsets_reversed = 1;
868
869 /* The reversed offset problem is present in some compilers
870 using DWARF3, but it was eventually fixed. Check the ARM
871 defined augmentations, which are in the format "armcc" followed
872 by a list of one-character options. The "+" option means
873 this problem is fixed (no quirk needed). If the armcc
874 augmentation is missing, the quirk is needed. */
875 if (fde->cie->version == 3
876 && (strncmp (fde->cie->augmentation, "armcc", 5) != 0
877 || strchr (fde->cie->augmentation + 5, '+') == NULL))
878 fs->armcc_cfa_offsets_reversed = 1;
879
880 return;
881 }
5796c8dc
SS
882}
883\f
884
c50c785c
JM
885void
886dwarf2_compile_cfa_to_ax (struct agent_expr *expr, struct axs_value *loc,
887 struct gdbarch *gdbarch,
888 CORE_ADDR pc,
889 struct dwarf2_per_cu_data *data)
890{
c50c785c 891 struct dwarf2_fde *fde;
ef5ccd6c 892 CORE_ADDR text_offset;
c50c785c
JM
893 struct dwarf2_frame_state fs;
894 int addr_size;
895
896 memset (&fs, 0, sizeof (struct dwarf2_frame_state));
897
898 fs.pc = pc;
899
900 /* Find the correct FDE. */
901 fde = dwarf2_frame_find_fde (&fs.pc, &text_offset);
902 if (fde == NULL)
903 error (_("Could not compute CFA; needed to translate this expression"));
904
905 /* Extract any interesting information from the CIE. */
906 fs.data_align = fde->cie->data_alignment_factor;
907 fs.code_align = fde->cie->code_alignment_factor;
908 fs.retaddr_column = fde->cie->return_address_register;
909 addr_size = fde->cie->addr_size;
910
911 /* Check for "quirks" - known bugs in producers. */
912 dwarf2_frame_find_quirks (&fs, fde);
913
914 /* First decode all the insns in the CIE. */
915 execute_cfa_program (fde, fde->cie->initial_instructions,
916 fde->cie->end, gdbarch, pc, &fs);
917
918 /* Save the initialized register set. */
919 fs.initial = fs.regs;
920 fs.initial.reg = dwarf2_frame_state_copy_regs (&fs.regs);
921
922 /* Then decode the insns in the FDE up to our target PC. */
923 execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs);
924
925 /* Calculate the CFA. */
926 switch (fs.regs.cfa_how)
927 {
928 case CFA_REG_OFFSET:
929 {
930 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, fs.regs.cfa_reg);
931
932 if (regnum == -1)
933 error (_("Unable to access DWARF register number %d"),
934 (int) fs.regs.cfa_reg); /* FIXME */
935 ax_reg (expr, regnum);
936
937 if (fs.regs.cfa_offset != 0)
938 {
939 if (fs.armcc_cfa_offsets_reversed)
940 ax_const_l (expr, -fs.regs.cfa_offset);
941 else
942 ax_const_l (expr, fs.regs.cfa_offset);
943 ax_simple (expr, aop_add);
944 }
945 }
946 break;
947
948 case CFA_EXP:
949 ax_const_l (expr, text_offset);
950 dwarf2_compile_expr_to_ax (expr, loc, gdbarch, addr_size,
951 fs.regs.cfa_exp,
952 fs.regs.cfa_exp + fs.regs.cfa_exp_len,
953 data);
954 break;
955
956 default:
957 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
958 }
959}
960
961\f
5796c8dc
SS
962struct dwarf2_frame_cache
963{
964 /* DWARF Call Frame Address. */
965 CORE_ADDR cfa;
966
c50c785c
JM
967 /* Set if the return address column was marked as unavailable
968 (required non-collected memory or registers to compute). */
969 int unavailable_retaddr;
970
5796c8dc
SS
971 /* Set if the return address column was marked as undefined. */
972 int undefined_retaddr;
973
974 /* Saved registers, indexed by GDB register number, not by DWARF
975 register number. */
976 struct dwarf2_frame_state_reg *reg;
977
978 /* Return address register. */
979 struct dwarf2_frame_state_reg retaddr_reg;
980
981 /* Target address size in bytes. */
982 int addr_size;
cf7f2e2d
JM
983
984 /* The .text offset. */
985 CORE_ADDR text_offset;
a45ae5f8
JM
986
987 /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME
988 sequence. If NULL then it is a normal case with no TAILCALL_FRAME
989 involved. Non-bottom frames of a virtual tail call frames chain use
990 dwarf2_tailcall_frame_unwind unwinder so this field does not apply for
991 them. */
992 void *tailcall_cache;
5796c8dc
SS
993};
994
ef5ccd6c
JM
995/* A cleanup that sets a pointer to NULL. */
996
997static void
998clear_pointer_cleanup (void *arg)
999{
1000 void **ptr = arg;
1001
1002 *ptr = NULL;
1003}
1004
5796c8dc
SS
1005static struct dwarf2_frame_cache *
1006dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
1007{
ef5ccd6c 1008 struct cleanup *reset_cache_cleanup, *old_chain;
5796c8dc
SS
1009 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1010 const int num_regs = gdbarch_num_regs (gdbarch)
1011 + gdbarch_num_pseudo_regs (gdbarch);
1012 struct dwarf2_frame_cache *cache;
1013 struct dwarf2_frame_state *fs;
1014 struct dwarf2_fde *fde;
c50c785c 1015 volatile struct gdb_exception ex;
a45ae5f8
JM
1016 CORE_ADDR entry_pc;
1017 LONGEST entry_cfa_sp_offset;
1018 int entry_cfa_sp_offset_p = 0;
1019 const gdb_byte *instr;
5796c8dc
SS
1020
1021 if (*this_cache)
1022 return *this_cache;
1023
1024 /* Allocate a new cache. */
1025 cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
1026 cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
c50c785c 1027 *this_cache = cache;
ef5ccd6c 1028 reset_cache_cleanup = make_cleanup (clear_pointer_cleanup, this_cache);
5796c8dc
SS
1029
1030 /* Allocate and initialize the frame state. */
c50c785c 1031 fs = XZALLOC (struct dwarf2_frame_state);
5796c8dc
SS
1032 old_chain = make_cleanup (dwarf2_frame_state_free, fs);
1033
1034 /* Unwind the PC.
1035
1036 Note that if the next frame is never supposed to return (i.e. a call
1037 to abort), the compiler might optimize away the instruction at
1038 its return address. As a result the return address will
1039 point at some random instruction, and the CFI for that
1040 instruction is probably worthless to us. GCC's unwinder solves
1041 this problem by substracting 1 from the return address to get an
1042 address in the middle of a presumed call instruction (or the
1043 instruction in the associated delay slot). This should only be
1044 done for "normal" frames and not for resume-type frames (signal
1045 handlers, sentinel frames, dummy frames). The function
1046 get_frame_address_in_block does just this. It's not clear how
1047 reliable the method is though; there is the potential for the
1048 register state pre-call being different to that on return. */
1049 fs->pc = get_frame_address_in_block (this_frame);
1050
1051 /* Find the correct FDE. */
cf7f2e2d 1052 fde = dwarf2_frame_find_fde (&fs->pc, &cache->text_offset);
5796c8dc
SS
1053 gdb_assert (fde != NULL);
1054
1055 /* Extract any interesting information from the CIE. */
1056 fs->data_align = fde->cie->data_alignment_factor;
1057 fs->code_align = fde->cie->code_alignment_factor;
1058 fs->retaddr_column = fde->cie->return_address_register;
1059 cache->addr_size = fde->cie->addr_size;
1060
1061 /* Check for "quirks" - known bugs in producers. */
1062 dwarf2_frame_find_quirks (fs, fde);
1063
1064 /* First decode all the insns in the CIE. */
1065 execute_cfa_program (fde, fde->cie->initial_instructions,
ef5ccd6c
JM
1066 fde->cie->end, gdbarch,
1067 get_frame_address_in_block (this_frame), fs);
5796c8dc
SS
1068
1069 /* Save the initialized register set. */
1070 fs->initial = fs->regs;
1071 fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs);
1072
a45ae5f8
JM
1073 if (get_frame_func_if_available (this_frame, &entry_pc))
1074 {
1075 /* Decode the insns in the FDE up to the entry PC. */
1076 instr = execute_cfa_program (fde, fde->instructions, fde->end, gdbarch,
1077 entry_pc, fs);
1078
1079 if (fs->regs.cfa_how == CFA_REG_OFFSET
1080 && (gdbarch_dwarf2_reg_to_regnum (gdbarch, fs->regs.cfa_reg)
1081 == gdbarch_sp_regnum (gdbarch)))
1082 {
1083 entry_cfa_sp_offset = fs->regs.cfa_offset;
1084 entry_cfa_sp_offset_p = 1;
1085 }
1086 }
1087 else
1088 instr = fde->instructions;
1089
5796c8dc 1090 /* Then decode the insns in the FDE up to our target PC. */
a45ae5f8 1091 execute_cfa_program (fde, instr, fde->end, gdbarch,
ef5ccd6c 1092 get_frame_address_in_block (this_frame), fs);
5796c8dc 1093
c50c785c 1094 TRY_CATCH (ex, RETURN_MASK_ERROR)
5796c8dc 1095 {
c50c785c
JM
1096 /* Calculate the CFA. */
1097 switch (fs->regs.cfa_how)
1098 {
1099 case CFA_REG_OFFSET:
1100 cache->cfa = read_reg (this_frame, fs->regs.cfa_reg);
1101 if (fs->armcc_cfa_offsets_reversed)
1102 cache->cfa -= fs->regs.cfa_offset;
1103 else
1104 cache->cfa += fs->regs.cfa_offset;
1105 break;
1106
1107 case CFA_EXP:
1108 cache->cfa =
1109 execute_stack_op (fs->regs.cfa_exp, fs->regs.cfa_exp_len,
1110 cache->addr_size, cache->text_offset,
1111 this_frame, 0, 0);
1112 break;
1113
1114 default:
1115 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
1116 }
1117 }
1118 if (ex.reason < 0)
1119 {
1120 if (ex.error == NOT_AVAILABLE_ERROR)
1121 {
1122 cache->unavailable_retaddr = 1;
ef5ccd6c
JM
1123 do_cleanups (old_chain);
1124 discard_cleanups (reset_cache_cleanup);
c50c785c
JM
1125 return cache;
1126 }
5796c8dc 1127
c50c785c 1128 throw_exception (ex);
5796c8dc
SS
1129 }
1130
1131 /* Initialize the register state. */
1132 {
1133 int regnum;
1134
1135 for (regnum = 0; regnum < num_regs; regnum++)
1136 dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame);
1137 }
1138
1139 /* Go through the DWARF2 CFI generated table and save its register
1140 location information in the cache. Note that we don't skip the
1141 return address column; it's perfectly all right for it to
1142 correspond to a real register. If it doesn't correspond to a
1143 real register, or if we shouldn't treat it as such,
1144 gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside
1145 the range [0, gdbarch_num_regs). */
1146 {
1147 int column; /* CFI speak for "register number". */
1148
1149 for (column = 0; column < fs->regs.num_regs; column++)
1150 {
1151 /* Use the GDB register number as the destination index. */
1152 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, column);
1153
1154 /* If there's no corresponding GDB register, ignore it. */
1155 if (regnum < 0 || regnum >= num_regs)
1156 continue;
1157
1158 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1159 of all debug info registers. If it doesn't, complain (but
1160 not too loudly). It turns out that GCC assumes that an
1161 unspecified register implies "same value" when CFI (draft
1162 7) specifies nothing at all. Such a register could equally
1163 be interpreted as "undefined". Also note that this check
1164 isn't sufficient; it only checks that all registers in the
1165 range [0 .. max column] are specified, and won't detect
1166 problems when a debug info register falls outside of the
1167 table. We need a way of iterating through all the valid
1168 DWARF2 register numbers. */
1169 if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
1170 {
1171 if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED)
1172 complaint (&symfile_complaints, _("\
1173incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1174 gdbarch_register_name (gdbarch, regnum),
1175 paddress (gdbarch, fs->pc));
1176 }
1177 else
1178 cache->reg[regnum] = fs->regs.reg[column];
1179 }
1180 }
1181
1182 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1183 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1184 {
1185 int regnum;
1186
1187 for (regnum = 0; regnum < num_regs; regnum++)
1188 {
1189 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
1190 || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
1191 {
1192 struct dwarf2_frame_state_reg *retaddr_reg =
1193 &fs->regs.reg[fs->retaddr_column];
1194
1195 /* It seems rather bizarre to specify an "empty" column as
1196 the return adress column. However, this is exactly
1197 what GCC does on some targets. It turns out that GCC
1198 assumes that the return address can be found in the
1199 register corresponding to the return address column.
1200 Incidentally, that's how we should treat a return
1201 address column specifying "same value" too. */
1202 if (fs->retaddr_column < fs->regs.num_regs
1203 && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
1204 && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
1205 {
1206 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1207 cache->reg[regnum] = *retaddr_reg;
1208 else
1209 cache->retaddr_reg = *retaddr_reg;
1210 }
1211 else
1212 {
1213 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1214 {
1215 cache->reg[regnum].loc.reg = fs->retaddr_column;
1216 cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
1217 }
1218 else
1219 {
1220 cache->retaddr_reg.loc.reg = fs->retaddr_column;
1221 cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG;
1222 }
1223 }
1224 }
1225 }
1226 }
1227
1228 if (fs->retaddr_column < fs->regs.num_regs
1229 && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
1230 cache->undefined_retaddr = 1;
1231
1232 do_cleanups (old_chain);
1233
a45ae5f8
JM
1234 /* Try to find a virtual tail call frames chain with bottom (callee) frame
1235 starting at THIS_FRAME. */
1236 dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache,
1237 (entry_cfa_sp_offset_p
1238 ? &entry_cfa_sp_offset : NULL));
1239
ef5ccd6c 1240 discard_cleanups (reset_cache_cleanup);
5796c8dc
SS
1241 return cache;
1242}
1243
c50c785c
JM
1244static enum unwind_stop_reason
1245dwarf2_frame_unwind_stop_reason (struct frame_info *this_frame,
1246 void **this_cache)
1247{
1248 struct dwarf2_frame_cache *cache
1249 = dwarf2_frame_cache (this_frame, this_cache);
1250
1251 if (cache->unavailable_retaddr)
1252 return UNWIND_UNAVAILABLE;
1253
1254 if (cache->undefined_retaddr)
1255 return UNWIND_OUTERMOST;
1256
1257 return UNWIND_NO_REASON;
1258}
1259
5796c8dc
SS
1260static void
1261dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
1262 struct frame_id *this_id)
1263{
1264 struct dwarf2_frame_cache *cache =
1265 dwarf2_frame_cache (this_frame, this_cache);
1266
c50c785c
JM
1267 if (cache->unavailable_retaddr)
1268 return;
1269
5796c8dc
SS
1270 if (cache->undefined_retaddr)
1271 return;
1272
1273 (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
1274}
1275
1276static struct value *
1277dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache,
1278 int regnum)
1279{
1280 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1281 struct dwarf2_frame_cache *cache =
1282 dwarf2_frame_cache (this_frame, this_cache);
1283 CORE_ADDR addr;
1284 int realnum;
1285
a45ae5f8
JM
1286 /* Non-bottom frames of a virtual tail call frames chain use
1287 dwarf2_tailcall_frame_unwind unwinder so this code does not apply for
1288 them. If dwarf2_tailcall_prev_register_first does not have specific value
1289 unwind the register, tail call frames are assumed to have the register set
1290 of the top caller. */
1291 if (cache->tailcall_cache)
1292 {
1293 struct value *val;
1294
1295 val = dwarf2_tailcall_prev_register_first (this_frame,
1296 &cache->tailcall_cache,
1297 regnum);
1298 if (val)
1299 return val;
1300 }
1301
5796c8dc
SS
1302 switch (cache->reg[regnum].how)
1303 {
1304 case DWARF2_FRAME_REG_UNDEFINED:
1305 /* If CFI explicitly specified that the value isn't defined,
1306 mark it as optimized away; the value isn't available. */
1307 return frame_unwind_got_optimized (this_frame, regnum);
1308
1309 case DWARF2_FRAME_REG_SAVED_OFFSET:
1310 addr = cache->cfa + cache->reg[regnum].loc.offset;
1311 return frame_unwind_got_memory (this_frame, regnum, addr);
1312
1313 case DWARF2_FRAME_REG_SAVED_REG:
1314 realnum
1315 = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg);
1316 return frame_unwind_got_register (this_frame, regnum, realnum);
1317
1318 case DWARF2_FRAME_REG_SAVED_EXP:
1319 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1320 cache->reg[regnum].exp_len,
cf7f2e2d
JM
1321 cache->addr_size, cache->text_offset,
1322 this_frame, cache->cfa, 1);
5796c8dc
SS
1323 return frame_unwind_got_memory (this_frame, regnum, addr);
1324
1325 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET:
1326 addr = cache->cfa + cache->reg[regnum].loc.offset;
1327 return frame_unwind_got_constant (this_frame, regnum, addr);
1328
1329 case DWARF2_FRAME_REG_SAVED_VAL_EXP:
1330 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1331 cache->reg[regnum].exp_len,
cf7f2e2d
JM
1332 cache->addr_size, cache->text_offset,
1333 this_frame, cache->cfa, 1);
5796c8dc
SS
1334 return frame_unwind_got_constant (this_frame, regnum, addr);
1335
1336 case DWARF2_FRAME_REG_UNSPECIFIED:
1337 /* GCC, in its infinite wisdom decided to not provide unwind
1338 information for registers that are "same value". Since
1339 DWARF2 (3 draft 7) doesn't define such behavior, said
1340 registers are actually undefined (which is different to CFI
1341 "undefined"). Code above issues a complaint about this.
1342 Here just fudge the books, assume GCC, and that the value is
1343 more inner on the stack. */
1344 return frame_unwind_got_register (this_frame, regnum, regnum);
1345
1346 case DWARF2_FRAME_REG_SAME_VALUE:
1347 return frame_unwind_got_register (this_frame, regnum, regnum);
1348
1349 case DWARF2_FRAME_REG_CFA:
1350 return frame_unwind_got_address (this_frame, regnum, cache->cfa);
1351
1352 case DWARF2_FRAME_REG_CFA_OFFSET:
1353 addr = cache->cfa + cache->reg[regnum].loc.offset;
1354 return frame_unwind_got_address (this_frame, regnum, addr);
1355
1356 case DWARF2_FRAME_REG_RA_OFFSET:
1357 addr = cache->reg[regnum].loc.offset;
1358 regnum = gdbarch_dwarf2_reg_to_regnum
1359 (gdbarch, cache->retaddr_reg.loc.reg);
1360 addr += get_frame_register_unsigned (this_frame, regnum);
1361 return frame_unwind_got_address (this_frame, regnum, addr);
1362
1363 case DWARF2_FRAME_REG_FN:
1364 return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum);
1365
1366 default:
1367 internal_error (__FILE__, __LINE__, _("Unknown register rule."));
1368 }
1369}
1370
a45ae5f8
JM
1371/* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail
1372 call frames chain. */
1373
1374static void
1375dwarf2_frame_dealloc_cache (struct frame_info *self, void *this_cache)
1376{
1377 struct dwarf2_frame_cache *cache = dwarf2_frame_cache (self, &this_cache);
1378
1379 if (cache->tailcall_cache)
1380 dwarf2_tailcall_frame_unwind.dealloc_cache (self, cache->tailcall_cache);
1381}
1382
5796c8dc
SS
1383static int
1384dwarf2_frame_sniffer (const struct frame_unwind *self,
1385 struct frame_info *this_frame, void **this_cache)
1386{
1387 /* Grab an address that is guarenteed to reside somewhere within the
1388 function. get_frame_pc(), with a no-return next function, can
1389 end up returning something past the end of this function's body.
1390 If the frame we're sniffing for is a signal frame whose start
1391 address is placed on the stack by the OS, its FDE must
1392 extend one byte before its start address or we could potentially
1393 select the FDE of the previous function. */
1394 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
cf7f2e2d
JM
1395 struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr, NULL);
1396
5796c8dc
SS
1397 if (!fde)
1398 return 0;
1399
1400 /* On some targets, signal trampolines may have unwind information.
1401 We need to recognize them so that we set the frame type
1402 correctly. */
1403
1404 if (fde->cie->signal_frame
1405 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame),
1406 this_frame))
1407 return self->type == SIGTRAMP_FRAME;
1408
a45ae5f8
JM
1409 if (self->type != NORMAL_FRAME)
1410 return 0;
1411
1412 /* Preinitializa the cache so that TAILCALL_FRAME can find the record by
1413 dwarf2_tailcall_sniffer_first. */
1414 dwarf2_frame_cache (this_frame, this_cache);
1415
1416 return 1;
5796c8dc
SS
1417}
1418
1419static const struct frame_unwind dwarf2_frame_unwind =
1420{
1421 NORMAL_FRAME,
c50c785c 1422 dwarf2_frame_unwind_stop_reason,
5796c8dc
SS
1423 dwarf2_frame_this_id,
1424 dwarf2_frame_prev_register,
1425 NULL,
a45ae5f8
JM
1426 dwarf2_frame_sniffer,
1427 dwarf2_frame_dealloc_cache
5796c8dc
SS
1428};
1429
1430static const struct frame_unwind dwarf2_signal_frame_unwind =
1431{
1432 SIGTRAMP_FRAME,
c50c785c 1433 dwarf2_frame_unwind_stop_reason,
5796c8dc
SS
1434 dwarf2_frame_this_id,
1435 dwarf2_frame_prev_register,
1436 NULL,
a45ae5f8
JM
1437 dwarf2_frame_sniffer,
1438
1439 /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */
1440 NULL
5796c8dc
SS
1441};
1442
1443/* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1444
1445void
1446dwarf2_append_unwinders (struct gdbarch *gdbarch)
1447{
a45ae5f8
JM
1448 /* TAILCALL_FRAME must be first to find the record by
1449 dwarf2_tailcall_sniffer_first. */
1450 frame_unwind_append_unwinder (gdbarch, &dwarf2_tailcall_frame_unwind);
1451
5796c8dc
SS
1452 frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind);
1453 frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind);
1454}
1455\f
1456
1457/* There is no explicitly defined relationship between the CFA and the
1458 location of frame's local variables and arguments/parameters.
1459 Therefore, frame base methods on this page should probably only be
1460 used as a last resort, just to avoid printing total garbage as a
1461 response to the "info frame" command. */
1462
1463static CORE_ADDR
1464dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache)
1465{
1466 struct dwarf2_frame_cache *cache =
1467 dwarf2_frame_cache (this_frame, this_cache);
1468
1469 return cache->cfa;
1470}
1471
1472static const struct frame_base dwarf2_frame_base =
1473{
1474 &dwarf2_frame_unwind,
1475 dwarf2_frame_base_address,
1476 dwarf2_frame_base_address,
1477 dwarf2_frame_base_address
1478};
1479
1480const struct frame_base *
1481dwarf2_frame_base_sniffer (struct frame_info *this_frame)
1482{
1483 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
cf7f2e2d
JM
1484
1485 if (dwarf2_frame_find_fde (&block_addr, NULL))
5796c8dc
SS
1486 return &dwarf2_frame_base;
1487
1488 return NULL;
1489}
1490
1491/* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1492 the DWARF unwinder. This is used to implement
1493 DW_OP_call_frame_cfa. */
1494
1495CORE_ADDR
1496dwarf2_frame_cfa (struct frame_info *this_frame)
1497{
1498 while (get_frame_type (this_frame) == INLINE_FRAME)
1499 this_frame = get_prev_frame (this_frame);
1500 /* This restriction could be lifted if other unwinders are known to
1501 compute the frame base in a way compatible with the DWARF
1502 unwinder. */
a45ae5f8
JM
1503 if (!frame_unwinder_is (this_frame, &dwarf2_frame_unwind)
1504 && !frame_unwinder_is (this_frame, &dwarf2_tailcall_frame_unwind))
5796c8dc 1505 error (_("can't compute CFA for this frame"));
ef5ccd6c
JM
1506 if (get_frame_unwind_stop_reason (this_frame) == UNWIND_UNAVAILABLE)
1507 throw_error (NOT_AVAILABLE_ERROR,
1508 _("can't compute CFA for this frame: "
1509 "required registers or memory are unavailable"));
5796c8dc
SS
1510 return get_frame_base (this_frame);
1511}
1512\f
1513const struct objfile_data *dwarf2_frame_objfile_data;
1514
1515static unsigned int
ef5ccd6c 1516read_1_byte (bfd *abfd, const gdb_byte *buf)
5796c8dc
SS
1517{
1518 return bfd_get_8 (abfd, buf);
1519}
1520
1521static unsigned int
ef5ccd6c 1522read_4_bytes (bfd *abfd, const gdb_byte *buf)
5796c8dc
SS
1523{
1524 return bfd_get_32 (abfd, buf);
1525}
1526
1527static ULONGEST
ef5ccd6c 1528read_8_bytes (bfd *abfd, const gdb_byte *buf)
5796c8dc
SS
1529{
1530 return bfd_get_64 (abfd, buf);
1531}
1532
1533static ULONGEST
ef5ccd6c
JM
1534read_initial_length (bfd *abfd, const gdb_byte *buf,
1535 unsigned int *bytes_read_ptr)
5796c8dc
SS
1536{
1537 LONGEST result;
1538
1539 result = bfd_get_32 (abfd, buf);
1540 if (result == 0xffffffff)
1541 {
1542 result = bfd_get_64 (abfd, buf + 4);
1543 *bytes_read_ptr = 12;
1544 }
1545 else
1546 *bytes_read_ptr = 4;
1547
1548 return result;
1549}
1550\f
1551
1552/* Pointer encoding helper functions. */
1553
1554/* GCC supports exception handling based on DWARF2 CFI. However, for
1555 technical reasons, it encodes addresses in its FDE's in a different
1556 way. Several "pointer encodings" are supported. The encoding
1557 that's used for a particular FDE is determined by the 'R'
1558 augmentation in the associated CIE. The argument of this
1559 augmentation is a single byte.
1560
1561 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1562 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1563 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1564 address should be interpreted (absolute, relative to the current
1565 position in the FDE, ...). Bit 7, indicates that the address
1566 should be dereferenced. */
1567
1568static gdb_byte
1569encoding_for_size (unsigned int size)
1570{
1571 switch (size)
1572 {
1573 case 2:
1574 return DW_EH_PE_udata2;
1575 case 4:
1576 return DW_EH_PE_udata4;
1577 case 8:
1578 return DW_EH_PE_udata8;
1579 default:
1580 internal_error (__FILE__, __LINE__, _("Unsupported address size"));
1581 }
1582}
1583
1584static CORE_ADDR
1585read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
cf7f2e2d
JM
1586 int ptr_len, const gdb_byte *buf,
1587 unsigned int *bytes_read_ptr,
5796c8dc
SS
1588 CORE_ADDR func_base)
1589{
1590 ptrdiff_t offset;
1591 CORE_ADDR base;
1592
1593 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1594 FDE's. */
1595 if (encoding & DW_EH_PE_indirect)
1596 internal_error (__FILE__, __LINE__,
1597 _("Unsupported encoding: DW_EH_PE_indirect"));
1598
1599 *bytes_read_ptr = 0;
1600
1601 switch (encoding & 0x70)
1602 {
1603 case DW_EH_PE_absptr:
1604 base = 0;
1605 break;
1606 case DW_EH_PE_pcrel:
1607 base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section);
1608 base += (buf - unit->dwarf_frame_buffer);
1609 break;
1610 case DW_EH_PE_datarel:
1611 base = unit->dbase;
1612 break;
1613 case DW_EH_PE_textrel:
1614 base = unit->tbase;
1615 break;
1616 case DW_EH_PE_funcrel:
1617 base = func_base;
1618 break;
1619 case DW_EH_PE_aligned:
1620 base = 0;
1621 offset = buf - unit->dwarf_frame_buffer;
1622 if ((offset % ptr_len) != 0)
1623 {
1624 *bytes_read_ptr = ptr_len - (offset % ptr_len);
1625 buf += *bytes_read_ptr;
1626 }
1627 break;
1628 default:
c50c785c
JM
1629 internal_error (__FILE__, __LINE__,
1630 _("Invalid or unsupported encoding"));
5796c8dc
SS
1631 }
1632
1633 if ((encoding & 0x07) == 0x00)
1634 {
1635 encoding |= encoding_for_size (ptr_len);
1636 if (bfd_get_sign_extend_vma (unit->abfd))
1637 encoding |= DW_EH_PE_signed;
1638 }
1639
1640 switch (encoding & 0x0f)
1641 {
1642 case DW_EH_PE_uleb128:
1643 {
ef5ccd6c 1644 uint64_t value;
cf7f2e2d
JM
1645 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1646
ef5ccd6c 1647 *bytes_read_ptr += safe_read_uleb128 (buf, end_buf, &value) - buf;
5796c8dc
SS
1648 return base + value;
1649 }
1650 case DW_EH_PE_udata2:
1651 *bytes_read_ptr += 2;
1652 return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf));
1653 case DW_EH_PE_udata4:
1654 *bytes_read_ptr += 4;
1655 return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf));
1656 case DW_EH_PE_udata8:
1657 *bytes_read_ptr += 8;
1658 return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf));
1659 case DW_EH_PE_sleb128:
1660 {
ef5ccd6c 1661 int64_t value;
cf7f2e2d
JM
1662 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1663
ef5ccd6c 1664 *bytes_read_ptr += safe_read_sleb128 (buf, end_buf, &value) - buf;
5796c8dc
SS
1665 return base + value;
1666 }
1667 case DW_EH_PE_sdata2:
1668 *bytes_read_ptr += 2;
1669 return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf));
1670 case DW_EH_PE_sdata4:
1671 *bytes_read_ptr += 4;
1672 return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf));
1673 case DW_EH_PE_sdata8:
1674 *bytes_read_ptr += 8;
1675 return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf));
1676 default:
c50c785c
JM
1677 internal_error (__FILE__, __LINE__,
1678 _("Invalid or unsupported encoding"));
5796c8dc
SS
1679 }
1680}
1681\f
1682
1683static int
1684bsearch_cie_cmp (const void *key, const void *element)
1685{
1686 ULONGEST cie_pointer = *(ULONGEST *) key;
1687 struct dwarf2_cie *cie = *(struct dwarf2_cie **) element;
1688
1689 if (cie_pointer == cie->cie_pointer)
1690 return 0;
1691
1692 return (cie_pointer < cie->cie_pointer) ? -1 : 1;
1693}
1694
1695/* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1696static struct dwarf2_cie *
1697find_cie (struct dwarf2_cie_table *cie_table, ULONGEST cie_pointer)
1698{
1699 struct dwarf2_cie **p_cie;
1700
cf7f2e2d
JM
1701 /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
1702 bsearch be non-NULL. */
1703 if (cie_table->entries == NULL)
1704 {
1705 gdb_assert (cie_table->num_entries == 0);
1706 return NULL;
1707 }
1708
5796c8dc
SS
1709 p_cie = bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries,
1710 sizeof (cie_table->entries[0]), bsearch_cie_cmp);
1711 if (p_cie != NULL)
1712 return *p_cie;
1713 return NULL;
1714}
1715
1716/* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1717static void
1718add_cie (struct dwarf2_cie_table *cie_table, struct dwarf2_cie *cie)
1719{
1720 const int n = cie_table->num_entries;
1721
1722 gdb_assert (n < 1
1723 || cie_table->entries[n - 1]->cie_pointer < cie->cie_pointer);
1724
1725 cie_table->entries =
1726 xrealloc (cie_table->entries, (n + 1) * sizeof (cie_table->entries[0]));
1727 cie_table->entries[n] = cie;
1728 cie_table->num_entries = n + 1;
1729}
1730
1731static int
1732bsearch_fde_cmp (const void *key, const void *element)
1733{
1734 CORE_ADDR seek_pc = *(CORE_ADDR *) key;
1735 struct dwarf2_fde *fde = *(struct dwarf2_fde **) element;
cf7f2e2d 1736
5796c8dc
SS
1737 if (seek_pc < fde->initial_location)
1738 return -1;
1739 if (seek_pc < fde->initial_location + fde->address_range)
1740 return 0;
1741 return 1;
1742}
1743
1744/* Find the FDE for *PC. Return a pointer to the FDE, and store the
1745 inital location associated with it into *PC. */
1746
1747static struct dwarf2_fde *
cf7f2e2d 1748dwarf2_frame_find_fde (CORE_ADDR *pc, CORE_ADDR *out_offset)
5796c8dc
SS
1749{
1750 struct objfile *objfile;
1751
1752 ALL_OBJFILES (objfile)
1753 {
1754 struct dwarf2_fde_table *fde_table;
1755 struct dwarf2_fde **p_fde;
1756 CORE_ADDR offset;
1757 CORE_ADDR seek_pc;
1758
1759 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1760 if (fde_table == NULL)
cf7f2e2d
JM
1761 {
1762 dwarf2_build_frame_info (objfile);
1763 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1764 }
1765 gdb_assert (fde_table != NULL);
1766
1767 if (fde_table->num_entries == 0)
5796c8dc
SS
1768 continue;
1769
1770 gdb_assert (objfile->section_offsets);
1771 offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
1772
1773 gdb_assert (fde_table->num_entries > 0);
1774 if (*pc < offset + fde_table->entries[0]->initial_location)
1775 continue;
1776
1777 seek_pc = *pc - offset;
1778 p_fde = bsearch (&seek_pc, fde_table->entries, fde_table->num_entries,
1779 sizeof (fde_table->entries[0]), bsearch_fde_cmp);
1780 if (p_fde != NULL)
1781 {
1782 *pc = (*p_fde)->initial_location + offset;
cf7f2e2d
JM
1783 if (out_offset)
1784 *out_offset = offset;
5796c8dc
SS
1785 return *p_fde;
1786 }
1787 }
1788 return NULL;
1789}
1790
1791/* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1792static void
1793add_fde (struct dwarf2_fde_table *fde_table, struct dwarf2_fde *fde)
1794{
1795 if (fde->address_range == 0)
1796 /* Discard useless FDEs. */
1797 return;
1798
1799 fde_table->num_entries += 1;
1800 fde_table->entries =
1801 xrealloc (fde_table->entries,
1802 fde_table->num_entries * sizeof (fde_table->entries[0]));
1803 fde_table->entries[fde_table->num_entries - 1] = fde;
1804}
1805
5796c8dc 1806#define DW64_CIE_ID 0xffffffffffffffffULL
5796c8dc 1807
a45ae5f8
JM
1808/* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
1809 or any of them. */
1810
1811enum eh_frame_type
1812{
1813 EH_CIE_TYPE_ID = 1 << 0,
1814 EH_FDE_TYPE_ID = 1 << 1,
1815 EH_CIE_OR_FDE_TYPE_ID = EH_CIE_TYPE_ID | EH_FDE_TYPE_ID
1816};
1817
ef5ccd6c
JM
1818static const gdb_byte *decode_frame_entry (struct comp_unit *unit,
1819 const gdb_byte *start,
1820 int eh_frame_p,
1821 struct dwarf2_cie_table *cie_table,
1822 struct dwarf2_fde_table *fde_table,
1823 enum eh_frame_type entry_type);
a45ae5f8
JM
1824
1825/* Decode the next CIE or FDE, entry_type specifies the expected type.
1826 Return NULL if invalid input, otherwise the next byte to be processed. */
5796c8dc 1827
ef5ccd6c
JM
1828static const gdb_byte *
1829decode_frame_entry_1 (struct comp_unit *unit, const gdb_byte *start,
1830 int eh_frame_p,
5796c8dc 1831 struct dwarf2_cie_table *cie_table,
a45ae5f8
JM
1832 struct dwarf2_fde_table *fde_table,
1833 enum eh_frame_type entry_type)
5796c8dc
SS
1834{
1835 struct gdbarch *gdbarch = get_objfile_arch (unit->objfile);
ef5ccd6c 1836 const gdb_byte *buf, *end;
5796c8dc
SS
1837 LONGEST length;
1838 unsigned int bytes_read;
1839 int dwarf64_p;
1840 ULONGEST cie_id;
1841 ULONGEST cie_pointer;
ef5ccd6c
JM
1842 int64_t sleb128;
1843 uint64_t uleb128;
5796c8dc
SS
1844
1845 buf = start;
1846 length = read_initial_length (unit->abfd, buf, &bytes_read);
1847 buf += bytes_read;
1848 end = buf + length;
1849
c50c785c 1850 /* Are we still within the section? */
5796c8dc
SS
1851 if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
1852 return NULL;
1853
1854 if (length == 0)
1855 return end;
1856
1857 /* Distinguish between 32 and 64-bit encoded frame info. */
1858 dwarf64_p = (bytes_read == 12);
1859
1860 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1861 if (eh_frame_p)
1862 cie_id = 0;
1863 else if (dwarf64_p)
1864 cie_id = DW64_CIE_ID;
1865 else
1866 cie_id = DW_CIE_ID;
1867
1868 if (dwarf64_p)
1869 {
1870 cie_pointer = read_8_bytes (unit->abfd, buf);
1871 buf += 8;
1872 }
1873 else
1874 {
1875 cie_pointer = read_4_bytes (unit->abfd, buf);
1876 buf += 4;
1877 }
1878
1879 if (cie_pointer == cie_id)
1880 {
1881 /* This is a CIE. */
1882 struct dwarf2_cie *cie;
1883 char *augmentation;
1884 unsigned int cie_version;
1885
a45ae5f8
JM
1886 /* Check that a CIE was expected. */
1887 if ((entry_type & EH_CIE_TYPE_ID) == 0)
1888 error (_("Found a CIE when not expecting it."));
1889
5796c8dc
SS
1890 /* Record the offset into the .debug_frame section of this CIE. */
1891 cie_pointer = start - unit->dwarf_frame_buffer;
1892
1893 /* Check whether we've already read it. */
1894 if (find_cie (cie_table, cie_pointer))
1895 return end;
1896
1897 cie = (struct dwarf2_cie *)
1898 obstack_alloc (&unit->objfile->objfile_obstack,
1899 sizeof (struct dwarf2_cie));
1900 cie->initial_instructions = NULL;
1901 cie->cie_pointer = cie_pointer;
1902
1903 /* The encoding for FDE's in a normal .debug_frame section
1904 depends on the target address size. */
1905 cie->encoding = DW_EH_PE_absptr;
1906
5796c8dc
SS
1907 /* We'll determine the final value later, but we need to
1908 initialize it conservatively. */
1909 cie->signal_frame = 0;
1910
1911 /* Check version number. */
1912 cie_version = read_1_byte (unit->abfd, buf);
cf7f2e2d 1913 if (cie_version != 1 && cie_version != 3 && cie_version != 4)
5796c8dc
SS
1914 return NULL;
1915 cie->version = cie_version;
1916 buf += 1;
1917
1918 /* Interpret the interesting bits of the augmentation. */
1919 cie->augmentation = augmentation = (char *) buf;
1920 buf += (strlen (augmentation) + 1);
1921
1922 /* Ignore armcc augmentations. We only use them for quirks,
1923 and that doesn't happen until later. */
1924 if (strncmp (augmentation, "armcc", 5) == 0)
1925 augmentation += strlen (augmentation);
1926
1927 /* The GCC 2.x "eh" augmentation has a pointer immediately
1928 following the augmentation string, so it must be handled
1929 first. */
1930 if (augmentation[0] == 'e' && augmentation[1] == 'h')
1931 {
1932 /* Skip. */
1933 buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1934 augmentation += 2;
1935 }
1936
cf7f2e2d
JM
1937 if (cie->version >= 4)
1938 {
1939 /* FIXME: check that this is the same as from the CU header. */
1940 cie->addr_size = read_1_byte (unit->abfd, buf);
1941 ++buf;
1942 cie->segment_size = read_1_byte (unit->abfd, buf);
1943 ++buf;
1944 }
1945 else
1946 {
c50c785c 1947 cie->addr_size = gdbarch_dwarf2_addr_size (gdbarch);
cf7f2e2d
JM
1948 cie->segment_size = 0;
1949 }
c50c785c
JM
1950 /* Address values in .eh_frame sections are defined to have the
1951 target's pointer size. Watchout: This breaks frame info for
1952 targets with pointer size < address size, unless a .debug_frame
1953 section exists as well. */
1954 if (eh_frame_p)
1955 cie->ptr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1956 else
1957 cie->ptr_size = cie->addr_size;
cf7f2e2d 1958
ef5ccd6c
JM
1959 buf = gdb_read_uleb128 (buf, end, &uleb128);
1960 if (buf == NULL)
1961 return NULL;
1962 cie->code_alignment_factor = uleb128;
5796c8dc 1963
ef5ccd6c
JM
1964 buf = gdb_read_sleb128 (buf, end, &sleb128);
1965 if (buf == NULL)
1966 return NULL;
1967 cie->data_alignment_factor = sleb128;
5796c8dc
SS
1968
1969 if (cie_version == 1)
1970 {
1971 cie->return_address_register = read_1_byte (unit->abfd, buf);
ef5ccd6c 1972 ++buf;
5796c8dc
SS
1973 }
1974 else
ef5ccd6c
JM
1975 {
1976 buf = gdb_read_uleb128 (buf, end, &uleb128);
1977 if (buf == NULL)
1978 return NULL;
1979 cie->return_address_register = uleb128;
1980 }
1981
5796c8dc
SS
1982 cie->return_address_register
1983 = dwarf2_frame_adjust_regnum (gdbarch,
1984 cie->return_address_register,
1985 eh_frame_p);
1986
5796c8dc
SS
1987 cie->saw_z_augmentation = (*augmentation == 'z');
1988 if (cie->saw_z_augmentation)
1989 {
ef5ccd6c 1990 uint64_t length;
5796c8dc 1991
ef5ccd6c
JM
1992 buf = gdb_read_uleb128 (buf, end, &length);
1993 if (buf == NULL)
5796c8dc
SS
1994 return NULL;
1995 cie->initial_instructions = buf + length;
1996 augmentation++;
1997 }
1998
1999 while (*augmentation)
2000 {
2001 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
2002 if (*augmentation == 'L')
2003 {
2004 /* Skip. */
2005 buf++;
2006 augmentation++;
2007 }
2008
2009 /* "R" indicates a byte indicating how FDE addresses are encoded. */
2010 else if (*augmentation == 'R')
2011 {
2012 cie->encoding = *buf++;
2013 augmentation++;
2014 }
2015
2016 /* "P" indicates a personality routine in the CIE augmentation. */
2017 else if (*augmentation == 'P')
2018 {
2019 /* Skip. Avoid indirection since we throw away the result. */
2020 gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect;
c50c785c 2021 read_encoded_value (unit, encoding, cie->ptr_size,
5796c8dc
SS
2022 buf, &bytes_read, 0);
2023 buf += bytes_read;
2024 augmentation++;
2025 }
2026
2027 /* "S" indicates a signal frame, such that the return
2028 address must not be decremented to locate the call frame
2029 info for the previous frame; it might even be the first
2030 instruction of a function, so decrementing it would take
2031 us to a different function. */
2032 else if (*augmentation == 'S')
2033 {
2034 cie->signal_frame = 1;
2035 augmentation++;
2036 }
2037
2038 /* Otherwise we have an unknown augmentation. Assume that either
2039 there is no augmentation data, or we saw a 'z' prefix. */
2040 else
2041 {
2042 if (cie->initial_instructions)
2043 buf = cie->initial_instructions;
2044 break;
2045 }
2046 }
2047
2048 cie->initial_instructions = buf;
2049 cie->end = end;
2050 cie->unit = unit;
2051
2052 add_cie (cie_table, cie);
2053 }
2054 else
2055 {
2056 /* This is a FDE. */
2057 struct dwarf2_fde *fde;
2058
a45ae5f8
JM
2059 /* Check that an FDE was expected. */
2060 if ((entry_type & EH_FDE_TYPE_ID) == 0)
2061 error (_("Found an FDE when not expecting it."));
2062
5796c8dc
SS
2063 /* In an .eh_frame section, the CIE pointer is the delta between the
2064 address within the FDE where the CIE pointer is stored and the
2065 address of the CIE. Convert it to an offset into the .eh_frame
2066 section. */
2067 if (eh_frame_p)
2068 {
2069 cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
2070 cie_pointer -= (dwarf64_p ? 8 : 4);
2071 }
2072
2073 /* In either case, validate the result is still within the section. */
2074 if (cie_pointer >= unit->dwarf_frame_size)
2075 return NULL;
2076
2077 fde = (struct dwarf2_fde *)
2078 obstack_alloc (&unit->objfile->objfile_obstack,
2079 sizeof (struct dwarf2_fde));
2080 fde->cie = find_cie (cie_table, cie_pointer);
2081 if (fde->cie == NULL)
2082 {
2083 decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer,
a45ae5f8
JM
2084 eh_frame_p, cie_table, fde_table,
2085 EH_CIE_TYPE_ID);
5796c8dc
SS
2086 fde->cie = find_cie (cie_table, cie_pointer);
2087 }
2088
2089 gdb_assert (fde->cie != NULL);
2090
2091 fde->initial_location =
c50c785c 2092 read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size,
5796c8dc
SS
2093 buf, &bytes_read, 0);
2094 buf += bytes_read;
2095
2096 fde->address_range =
2097 read_encoded_value (unit, fde->cie->encoding & 0x0f,
c50c785c 2098 fde->cie->ptr_size, buf, &bytes_read, 0);
5796c8dc
SS
2099 buf += bytes_read;
2100
2101 /* A 'z' augmentation in the CIE implies the presence of an
2102 augmentation field in the FDE as well. The only thing known
2103 to be in here at present is the LSDA entry for EH. So we
2104 can skip the whole thing. */
2105 if (fde->cie->saw_z_augmentation)
2106 {
ef5ccd6c 2107 uint64_t length;
5796c8dc 2108
ef5ccd6c
JM
2109 buf = gdb_read_uleb128 (buf, end, &length);
2110 if (buf == NULL)
2111 return NULL;
2112 buf += length;
5796c8dc
SS
2113 if (buf > end)
2114 return NULL;
2115 }
2116
2117 fde->instructions = buf;
2118 fde->end = end;
2119
2120 fde->eh_frame_p = eh_frame_p;
2121
2122 add_fde (fde_table, fde);
2123 }
2124
2125 return end;
2126}
2127
a45ae5f8
JM
2128/* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
2129 expect an FDE or a CIE. */
2130
ef5ccd6c
JM
2131static const gdb_byte *
2132decode_frame_entry (struct comp_unit *unit, const gdb_byte *start,
2133 int eh_frame_p,
5796c8dc 2134 struct dwarf2_cie_table *cie_table,
a45ae5f8
JM
2135 struct dwarf2_fde_table *fde_table,
2136 enum eh_frame_type entry_type)
5796c8dc
SS
2137{
2138 enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
ef5ccd6c 2139 const gdb_byte *ret;
5796c8dc
SS
2140 ptrdiff_t start_offset;
2141
2142 while (1)
2143 {
2144 ret = decode_frame_entry_1 (unit, start, eh_frame_p,
a45ae5f8 2145 cie_table, fde_table, entry_type);
5796c8dc
SS
2146 if (ret != NULL)
2147 break;
2148
2149 /* We have corrupt input data of some form. */
2150
2151 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
2152 and mismatches wrt padding and alignment of debug sections. */
2153 /* Note that there is no requirement in the standard for any
2154 alignment at all in the frame unwind sections. Testing for
2155 alignment before trying to interpret data would be incorrect.
2156
2157 However, GCC traditionally arranged for frame sections to be
2158 sized such that the FDE length and CIE fields happen to be
2159 aligned (in theory, for performance). This, unfortunately,
2160 was done with .align directives, which had the side effect of
2161 forcing the section to be aligned by the linker.
2162
2163 This becomes a problem when you have some other producer that
2164 creates frame sections that are not as strictly aligned. That
2165 produces a hole in the frame info that gets filled by the
2166 linker with zeros.
2167
2168 The GCC behaviour is arguably a bug, but it's effectively now
2169 part of the ABI, so we're now stuck with it, at least at the
2170 object file level. A smart linker may decide, in the process
2171 of compressing duplicate CIE information, that it can rewrite
2172 the entire output section without this extra padding. */
2173
2174 start_offset = start - unit->dwarf_frame_buffer;
2175 if (workaround < ALIGN4 && (start_offset & 3) != 0)
2176 {
2177 start += 4 - (start_offset & 3);
2178 workaround = ALIGN4;
2179 continue;
2180 }
2181 if (workaround < ALIGN8 && (start_offset & 7) != 0)
2182 {
2183 start += 8 - (start_offset & 7);
2184 workaround = ALIGN8;
2185 continue;
2186 }
2187
2188 /* Nothing left to try. Arrange to return as if we've consumed
2189 the entire input section. Hopefully we'll get valid info from
2190 the other of .debug_frame/.eh_frame. */
2191 workaround = FAIL;
2192 ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
2193 break;
2194 }
2195
2196 switch (workaround)
2197 {
2198 case NONE:
2199 break;
2200
2201 case ALIGN4:
c50c785c
JM
2202 complaint (&symfile_complaints, _("\
2203Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
5796c8dc
SS
2204 unit->dwarf_frame_section->owner->filename,
2205 unit->dwarf_frame_section->name);
2206 break;
2207
2208 case ALIGN8:
c50c785c
JM
2209 complaint (&symfile_complaints, _("\
2210Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
5796c8dc
SS
2211 unit->dwarf_frame_section->owner->filename,
2212 unit->dwarf_frame_section->name);
2213 break;
2214
2215 default:
2216 complaint (&symfile_complaints,
2217 _("Corrupt data in %s:%s"),
2218 unit->dwarf_frame_section->owner->filename,
2219 unit->dwarf_frame_section->name);
2220 break;
2221 }
2222
2223 return ret;
2224}
2225\f
5796c8dc
SS
2226static int
2227qsort_fde_cmp (const void *a, const void *b)
2228{
2229 struct dwarf2_fde *aa = *(struct dwarf2_fde **)a;
2230 struct dwarf2_fde *bb = *(struct dwarf2_fde **)b;
2231
2232 if (aa->initial_location == bb->initial_location)
2233 {
2234 if (aa->address_range != bb->address_range
2235 && aa->eh_frame_p == 0 && bb->eh_frame_p == 0)
2236 /* Linker bug, e.g. gold/10400.
2237 Work around it by keeping stable sort order. */
2238 return (a < b) ? -1 : 1;
2239 else
2240 /* Put eh_frame entries after debug_frame ones. */
2241 return aa->eh_frame_p - bb->eh_frame_p;
2242 }
2243
2244 return (aa->initial_location < bb->initial_location) ? -1 : 1;
2245}
2246
2247void
2248dwarf2_build_frame_info (struct objfile *objfile)
2249{
2250 struct comp_unit *unit;
ef5ccd6c 2251 const gdb_byte *frame_ptr;
5796c8dc
SS
2252 struct dwarf2_cie_table cie_table;
2253 struct dwarf2_fde_table fde_table;
cf7f2e2d 2254 struct dwarf2_fde_table *fde_table2;
a45ae5f8 2255 volatile struct gdb_exception e;
5796c8dc
SS
2256
2257 cie_table.num_entries = 0;
2258 cie_table.entries = NULL;
2259
2260 fde_table.num_entries = 0;
2261 fde_table.entries = NULL;
2262
2263 /* Build a minimal decoding of the DWARF2 compilation unit. */
2264 unit = (struct comp_unit *) obstack_alloc (&objfile->objfile_obstack,
2265 sizeof (struct comp_unit));
2266 unit->abfd = objfile->obfd;
2267 unit->objfile = objfile;
2268 unit->dbase = 0;
2269 unit->tbase = 0;
2270
a45ae5f8 2271 if (objfile->separate_debug_objfile_backlink == NULL)
5796c8dc 2272 {
a45ae5f8
JM
2273 /* Do not read .eh_frame from separate file as they must be also
2274 present in the main file. */
2275 dwarf2_get_section_info (objfile, DWARF2_EH_FRAME,
2276 &unit->dwarf_frame_section,
2277 &unit->dwarf_frame_buffer,
2278 &unit->dwarf_frame_size);
2279 if (unit->dwarf_frame_size)
5796c8dc 2280 {
a45ae5f8
JM
2281 asection *got, *txt;
2282
2283 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2284 that is used for the i386/amd64 target, which currently is
2285 the only target in GCC that supports/uses the
2286 DW_EH_PE_datarel encoding. */
2287 got = bfd_get_section_by_name (unit->abfd, ".got");
2288 if (got)
2289 unit->dbase = got->vma;
2290
2291 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2292 so far. */
2293 txt = bfd_get_section_by_name (unit->abfd, ".text");
2294 if (txt)
2295 unit->tbase = txt->vma;
2296
2297 TRY_CATCH (e, RETURN_MASK_ERROR)
2298 {
2299 frame_ptr = unit->dwarf_frame_buffer;
2300 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2301 frame_ptr = decode_frame_entry (unit, frame_ptr, 1,
2302 &cie_table, &fde_table,
2303 EH_CIE_OR_FDE_TYPE_ID);
2304 }
2305
2306 if (e.reason < 0)
2307 {
2308 warning (_("skipping .eh_frame info of %s: %s"),
2309 objfile->name, e.message);
2310
2311 if (fde_table.num_entries != 0)
2312 {
2313 xfree (fde_table.entries);
2314 fde_table.entries = NULL;
2315 fde_table.num_entries = 0;
2316 }
2317 /* The cie_table is discarded by the next if. */
2318 }
2319
2320 if (cie_table.num_entries != 0)
2321 {
2322 /* Reinit cie_table: debug_frame has different CIEs. */
2323 xfree (cie_table.entries);
2324 cie_table.num_entries = 0;
2325 cie_table.entries = NULL;
2326 }
5796c8dc
SS
2327 }
2328 }
2329
a45ae5f8 2330 dwarf2_get_section_info (objfile, DWARF2_DEBUG_FRAME,
5796c8dc
SS
2331 &unit->dwarf_frame_section,
2332 &unit->dwarf_frame_buffer,
2333 &unit->dwarf_frame_size);
2334 if (unit->dwarf_frame_size)
2335 {
a45ae5f8
JM
2336 int num_old_fde_entries = fde_table.num_entries;
2337
2338 TRY_CATCH (e, RETURN_MASK_ERROR)
2339 {
2340 frame_ptr = unit->dwarf_frame_buffer;
2341 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2342 frame_ptr = decode_frame_entry (unit, frame_ptr, 0,
2343 &cie_table, &fde_table,
2344 EH_CIE_OR_FDE_TYPE_ID);
2345 }
2346 if (e.reason < 0)
2347 {
2348 warning (_("skipping .debug_frame info of %s: %s"),
2349 objfile->name, e.message);
2350
2351 if (fde_table.num_entries != 0)
2352 {
2353 fde_table.num_entries = num_old_fde_entries;
2354 if (num_old_fde_entries == 0)
2355 {
2356 xfree (fde_table.entries);
2357 fde_table.entries = NULL;
2358 }
2359 else
2360 {
2361 fde_table.entries = xrealloc (fde_table.entries,
2362 fde_table.num_entries *
2363 sizeof (fde_table.entries[0]));
2364 }
2365 }
2366 fde_table.num_entries = num_old_fde_entries;
2367 /* The cie_table is discarded by the next if. */
2368 }
5796c8dc
SS
2369 }
2370
2371 /* Discard the cie_table, it is no longer needed. */
2372 if (cie_table.num_entries != 0)
2373 {
2374 xfree (cie_table.entries);
2375 cie_table.entries = NULL; /* Paranoia. */
2376 cie_table.num_entries = 0; /* Paranoia. */
2377 }
2378
cf7f2e2d
JM
2379 /* Copy fde_table to obstack: it is needed at runtime. */
2380 fde_table2 = (struct dwarf2_fde_table *)
2381 obstack_alloc (&objfile->objfile_obstack, sizeof (*fde_table2));
2382
2383 if (fde_table.num_entries == 0)
2384 {
2385 fde_table2->entries = NULL;
2386 fde_table2->num_entries = 0;
2387 }
2388 else
5796c8dc 2389 {
cf7f2e2d
JM
2390 struct dwarf2_fde *fde_prev = NULL;
2391 struct dwarf2_fde *first_non_zero_fde = NULL;
2392 int i;
5796c8dc
SS
2393
2394 /* Prepare FDE table for lookups. */
2395 qsort (fde_table.entries, fde_table.num_entries,
2396 sizeof (fde_table.entries[0]), qsort_fde_cmp);
2397
cf7f2e2d
JM
2398 /* Check for leftovers from --gc-sections. The GNU linker sets
2399 the relevant symbols to zero, but doesn't zero the FDE *end*
2400 ranges because there's no relocation there. It's (offset,
2401 length), not (start, end). On targets where address zero is
2402 just another valid address this can be a problem, since the
2403 FDEs appear to be non-empty in the output --- we could pick
2404 out the wrong FDE. To work around this, when overlaps are
2405 detected, we prefer FDEs that do not start at zero.
2406
2407 Start by finding the first FDE with non-zero start. Below
2408 we'll discard all FDEs that start at zero and overlap this
2409 one. */
2410 for (i = 0; i < fde_table.num_entries; i++)
2411 {
2412 struct dwarf2_fde *fde = fde_table.entries[i];
5796c8dc 2413
cf7f2e2d
JM
2414 if (fde->initial_location != 0)
2415 {
2416 first_non_zero_fde = fde;
2417 break;
2418 }
2419 }
2420
2421 /* Since we'll be doing bsearch, squeeze out identical (except
2422 for eh_frame_p) fde entries so bsearch result is predictable.
2423 Also discard leftovers from --gc-sections. */
2424 fde_table2->num_entries = 0;
2425 for (i = 0; i < fde_table.num_entries; i++)
2426 {
2427 struct dwarf2_fde *fde = fde_table.entries[i];
2428
2429 if (fde->initial_location == 0
2430 && first_non_zero_fde != NULL
2431 && (first_non_zero_fde->initial_location
2432 < fde->initial_location + fde->address_range))
2433 continue;
2434
2435 if (fde_prev != NULL
2436 && fde_prev->initial_location == fde->initial_location)
2437 continue;
2438
2439 obstack_grow (&objfile->objfile_obstack, &fde_table.entries[i],
2440 sizeof (fde_table.entries[0]));
2441 ++fde_table2->num_entries;
2442 fde_prev = fde;
2443 }
5796c8dc 2444 fde_table2->entries = obstack_finish (&objfile->objfile_obstack);
5796c8dc
SS
2445
2446 /* Discard the original fde_table. */
2447 xfree (fde_table.entries);
2448 }
cf7f2e2d
JM
2449
2450 set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2);
5796c8dc
SS
2451}
2452
2453/* Provide a prototype to silence -Wmissing-prototypes. */
2454void _initialize_dwarf2_frame (void);
2455
2456void
2457_initialize_dwarf2_frame (void)
2458{
2459 dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
2460 dwarf2_frame_objfile_data = register_objfile_data ();
2461}