1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright (C) 2003-2014 Free Software Foundation, Inc.
5 Contributed by Mark Kettenis.
7 This file is part of GDB.
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.
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.
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/>. */
23 #include "dwarf2expr.h"
26 #include "frame-base.h"
27 #include "frame-unwind.h"
38 #include "complaints.h"
39 #include "dwarf2-frame.h"
41 #include "dwarf2loc.h"
42 #include "exceptions.h"
43 #include "dwarf2-frame-tailcall.h"
47 /* Call Frame Information (CFI). */
49 /* Common Information Entry (CIE). */
53 /* Computation Unit for this CIE. */
54 struct comp_unit *unit;
56 /* Offset into the .debug_frame section where this CIE was found.
57 Used to identify this CIE. */
60 /* Constant that is factored out of all advance location
62 ULONGEST code_alignment_factor;
64 /* Constants that is factored out of all offset instructions. */
65 LONGEST data_alignment_factor;
67 /* Return address column. */
68 ULONGEST return_address_register;
70 /* Instruction sequence to initialize a register set. */
71 const gdb_byte *initial_instructions;
74 /* Saved augmentation, in case it's needed later. */
77 /* Encoding of addresses. */
80 /* Target address size in bytes. */
83 /* Target pointer size in bytes. */
86 /* True if a 'z' augmentation existed. */
87 unsigned char saw_z_augmentation;
89 /* True if an 'S' augmentation existed. */
90 unsigned char signal_frame;
92 /* The version recorded in the CIE. */
93 unsigned char version;
95 /* The segment size. */
96 unsigned char segment_size;
99 struct dwarf2_cie_table
102 struct dwarf2_cie **entries;
105 /* Frame Description Entry (FDE). */
109 /* CIE for this FDE. */
110 struct dwarf2_cie *cie;
112 /* First location associated with this FDE. */
113 CORE_ADDR initial_location;
115 /* Number of bytes of program instructions described by this FDE. */
116 CORE_ADDR address_range;
118 /* Instruction sequence. */
119 const gdb_byte *instructions;
122 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
124 unsigned char eh_frame_p;
127 struct dwarf2_fde_table
130 struct dwarf2_fde **entries;
133 /* A minimal decoding of DWARF2 compilation units. We only decode
134 what's needed to get to the call frame information. */
138 /* Keep the bfd convenient. */
141 struct objfile *objfile;
143 /* Pointer to the .debug_frame section loaded into memory. */
144 const gdb_byte *dwarf_frame_buffer;
146 /* Length of the loaded .debug_frame section. */
147 bfd_size_type dwarf_frame_size;
149 /* Pointer to the .debug_frame section. */
150 asection *dwarf_frame_section;
152 /* Base for DW_EH_PE_datarel encodings. */
155 /* Base for DW_EH_PE_textrel encodings. */
159 static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc,
160 CORE_ADDR *out_offset);
162 static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum,
165 static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
166 int ptr_len, const gdb_byte *buf,
167 unsigned int *bytes_read_ptr,
168 CORE_ADDR func_base);
171 /* Structure describing a frame state. */
173 struct dwarf2_frame_state
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
179 struct dwarf2_frame_state_reg *reg;
189 const gdb_byte *cfa_exp;
191 /* Used to implement DW_CFA_remember_state. */
192 struct dwarf2_frame_state_reg_info *prev;
195 /* The PC described by the current frame state. */
198 /* Initial register set from the CIE.
199 Used to implement DW_CFA_restore. */
200 struct dwarf2_frame_state_reg_info initial;
202 /* The information we care about from the CIE. */
205 ULONGEST retaddr_column;
207 /* Flags for known producer quirks. */
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;
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;
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
222 /* Assert that the register set RS is large enough to store gdbarch_num_regs
223 columns. If necessary, enlarge the register set. */
226 dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs,
229 size_t size = sizeof (struct dwarf2_frame_state_reg);
231 if (num_regs <= rs->num_regs)
234 rs->reg = (struct dwarf2_frame_state_reg *)
235 xrealloc (rs->reg, num_regs * size);
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;
242 /* Copy the register columns in register set RS into newly allocated
243 memory and return a pointer to this newly created copy. */
245 static struct dwarf2_frame_state_reg *
246 dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs)
248 size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg);
249 struct dwarf2_frame_state_reg *reg;
251 reg = (struct dwarf2_frame_state_reg *) xmalloc (size);
252 memcpy (reg, rs->reg, size);
257 /* Release the memory allocated to register set RS. */
260 dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs)
264 dwarf2_frame_state_free_regs (rs->prev);
271 /* Release the memory allocated to the frame state FS. */
274 dwarf2_frame_state_free (void *p)
276 struct dwarf2_frame_state *fs = p;
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);
286 /* Helper functions for execute_stack_op. */
289 read_addr_from_reg (void *baton, int reg)
291 struct frame_info *this_frame = (struct frame_info *) baton;
292 struct gdbarch *gdbarch = get_frame_arch (this_frame);
293 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
295 return address_from_register (regnum, this_frame);
298 /* Implement struct dwarf_expr_context_funcs' "get_reg_value" callback. */
300 static struct value *
301 get_reg_value (void *baton, struct type *type, int reg)
303 struct frame_info *this_frame = (struct frame_info *) baton;
304 struct gdbarch *gdbarch = get_frame_arch (this_frame);
305 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
307 return value_from_register (type, regnum, this_frame);
311 read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
313 read_memory (addr, buf, len);
316 /* Execute the required actions for both the DW_CFA_restore and
317 DW_CFA_restore_extended instructions. */
319 dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
320 struct dwarf2_frame_state *fs, int eh_frame_p)
324 gdb_assert (fs->initial.reg);
325 reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
326 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
328 /* Check if this register was explicitly initialized in the
329 CIE initial instructions. If not, default the rule to
331 if (reg < fs->initial.num_regs)
332 fs->regs.reg[reg] = fs->initial.reg[reg];
334 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;
336 if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED)
337 complaint (&symfile_complaints, _("\
338 incomplete CFI data; DW_CFA_restore unspecified\n\
339 register %s (#%d) at %s"),
340 gdbarch_register_name
341 (gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)),
342 gdbarch_dwarf2_reg_to_regnum (gdbarch, reg),
343 paddress (gdbarch, fs->pc));
346 /* Virtual method table for execute_stack_op below. */
348 static const struct dwarf_expr_context_funcs dwarf2_frame_ctx_funcs =
353 ctx_no_get_frame_base,
354 ctx_no_get_frame_cfa,
356 ctx_no_get_tls_address,
358 ctx_no_get_base_type,
359 ctx_no_push_dwarf_reg_entry_value,
360 ctx_no_get_addr_index
364 execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
365 CORE_ADDR offset, struct frame_info *this_frame,
366 CORE_ADDR initial, int initial_in_stack_memory)
368 struct dwarf_expr_context *ctx;
370 struct cleanup *old_chain;
372 ctx = new_dwarf_expr_context ();
373 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
374 make_cleanup_value_free_to_mark (value_mark ());
376 ctx->gdbarch = get_frame_arch (this_frame);
377 ctx->addr_size = addr_size;
378 ctx->ref_addr_size = -1;
379 ctx->offset = offset;
380 ctx->baton = this_frame;
381 ctx->funcs = &dwarf2_frame_ctx_funcs;
383 dwarf_expr_push_address (ctx, initial, initial_in_stack_memory);
384 dwarf_expr_eval (ctx, exp, len);
386 if (ctx->location == DWARF_VALUE_MEMORY)
387 result = dwarf_expr_fetch_address (ctx, 0);
388 else if (ctx->location == DWARF_VALUE_REGISTER)
389 result = read_addr_from_reg (this_frame,
390 value_as_long (dwarf_expr_fetch (ctx, 0)));
393 /* This is actually invalid DWARF, but if we ever do run across
394 it somehow, we might as well support it. So, instead, report
395 it as unimplemented. */
397 Not implemented: computing unwound register using explicit value operator"));
400 do_cleanups (old_chain);
406 /* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior
407 PC. Modify FS state accordingly. Return current INSN_PTR where the
408 execution has stopped, one can resume it on the next call. */
410 static const gdb_byte *
411 execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,
412 const gdb_byte *insn_end, struct gdbarch *gdbarch,
413 CORE_ADDR pc, struct dwarf2_frame_state *fs)
415 int eh_frame_p = fde->eh_frame_p;
416 unsigned int bytes_read;
417 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
419 while (insn_ptr < insn_end && fs->pc <= pc)
421 gdb_byte insn = *insn_ptr++;
425 if ((insn & 0xc0) == DW_CFA_advance_loc)
426 fs->pc += (insn & 0x3f) * fs->code_align;
427 else if ((insn & 0xc0) == DW_CFA_offset)
430 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
431 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
432 offset = utmp * fs->data_align;
433 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
434 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
435 fs->regs.reg[reg].loc.offset = offset;
437 else if ((insn & 0xc0) == DW_CFA_restore)
440 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
447 fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
448 fde->cie->ptr_size, insn_ptr,
449 &bytes_read, fde->initial_location);
450 /* Apply the objfile offset for relocatable objects. */
451 fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets,
452 SECT_OFF_TEXT (fde->cie->unit->objfile));
453 insn_ptr += bytes_read;
456 case DW_CFA_advance_loc1:
457 utmp = extract_unsigned_integer (insn_ptr, 1, byte_order);
458 fs->pc += utmp * fs->code_align;
461 case DW_CFA_advance_loc2:
462 utmp = extract_unsigned_integer (insn_ptr, 2, byte_order);
463 fs->pc += utmp * fs->code_align;
466 case DW_CFA_advance_loc4:
467 utmp = extract_unsigned_integer (insn_ptr, 4, byte_order);
468 fs->pc += utmp * fs->code_align;
472 case DW_CFA_offset_extended:
473 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
474 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
475 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
476 offset = utmp * fs->data_align;
477 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
478 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
479 fs->regs.reg[reg].loc.offset = offset;
482 case DW_CFA_restore_extended:
483 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
484 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
487 case DW_CFA_undefined:
488 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
489 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
490 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
491 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
494 case DW_CFA_same_value:
495 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
496 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
497 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
498 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE;
501 case DW_CFA_register:
502 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
503 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
504 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
505 utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p);
506 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
507 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
508 fs->regs.reg[reg].loc.reg = utmp;
511 case DW_CFA_remember_state:
513 struct dwarf2_frame_state_reg_info *new_rs;
515 new_rs = XNEW (struct dwarf2_frame_state_reg_info);
517 fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs);
518 fs->regs.prev = new_rs;
522 case DW_CFA_restore_state:
524 struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;
528 complaint (&symfile_complaints, _("\
529 bad CFI data; mismatched DW_CFA_restore_state at %s"),
530 paddress (gdbarch, fs->pc));
534 xfree (fs->regs.reg);
542 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
543 fs->regs.cfa_reg = reg;
544 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
546 if (fs->armcc_cfa_offsets_sf)
547 utmp *= fs->data_align;
549 fs->regs.cfa_offset = utmp;
550 fs->regs.cfa_how = CFA_REG_OFFSET;
553 case DW_CFA_def_cfa_register:
554 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
555 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
557 fs->regs.cfa_how = CFA_REG_OFFSET;
560 case DW_CFA_def_cfa_offset:
561 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
563 if (fs->armcc_cfa_offsets_sf)
564 utmp *= fs->data_align;
566 fs->regs.cfa_offset = utmp;
567 /* cfa_how deliberately not set. */
573 case DW_CFA_def_cfa_expression:
574 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
575 fs->regs.cfa_exp_len = utmp;
576 fs->regs.cfa_exp = insn_ptr;
577 fs->regs.cfa_how = CFA_EXP;
578 insn_ptr += fs->regs.cfa_exp_len;
581 case DW_CFA_expression:
582 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
583 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
584 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
585 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
586 fs->regs.reg[reg].loc.exp = insn_ptr;
587 fs->regs.reg[reg].exp_len = utmp;
588 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
592 case DW_CFA_offset_extended_sf:
593 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
594 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
595 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
596 offset *= fs->data_align;
597 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
598 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
599 fs->regs.reg[reg].loc.offset = offset;
602 case DW_CFA_val_offset:
603 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
604 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
605 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
606 offset = utmp * fs->data_align;
607 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
608 fs->regs.reg[reg].loc.offset = offset;
611 case DW_CFA_val_offset_sf:
612 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
613 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
614 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
615 offset *= fs->data_align;
616 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
617 fs->regs.reg[reg].loc.offset = offset;
620 case DW_CFA_val_expression:
621 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
622 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
623 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
624 fs->regs.reg[reg].loc.exp = insn_ptr;
625 fs->regs.reg[reg].exp_len = utmp;
626 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP;
630 case DW_CFA_def_cfa_sf:
631 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
632 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
634 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
635 fs->regs.cfa_offset = offset * fs->data_align;
636 fs->regs.cfa_how = CFA_REG_OFFSET;
639 case DW_CFA_def_cfa_offset_sf:
640 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
641 fs->regs.cfa_offset = offset * fs->data_align;
642 /* cfa_how deliberately not set. */
645 case DW_CFA_GNU_window_save:
646 /* This is SPARC-specific code, and contains hard-coded
647 constants for the register numbering scheme used by
648 GCC. Rather than having a architecture-specific
649 operation that's only ever used by a single
650 architecture, we provide the implementation here.
651 Incidentally that's what GCC does too in its
654 int size = register_size (gdbarch, 0);
656 dwarf2_frame_state_alloc_regs (&fs->regs, 32);
657 for (reg = 8; reg < 16; reg++)
659 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
660 fs->regs.reg[reg].loc.reg = reg + 16;
662 for (reg = 16; reg < 32; reg++)
664 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
665 fs->regs.reg[reg].loc.offset = (reg - 16) * size;
670 case DW_CFA_GNU_args_size:
672 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
675 case DW_CFA_GNU_negative_offset_extended:
676 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
677 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
678 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
679 offset = utmp * fs->data_align;
680 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
681 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
682 fs->regs.reg[reg].loc.offset = -offset;
686 internal_error (__FILE__, __LINE__,
687 _("Unknown CFI encountered."));
692 if (fs->initial.reg == NULL)
694 /* Don't allow remember/restore between CIE and FDE programs. */
695 dwarf2_frame_state_free_regs (fs->regs.prev);
696 fs->regs.prev = NULL;
703 /* Architecture-specific operations. */
705 /* Per-architecture data key. */
706 static struct gdbarch_data *dwarf2_frame_data;
708 struct dwarf2_frame_ops
710 /* Pre-initialize the register state REG for register REGNUM. */
711 void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *,
712 struct frame_info *);
714 /* Check whether the THIS_FRAME is a signal trampoline. */
715 int (*signal_frame_p) (struct gdbarch *, struct frame_info *);
717 /* Convert .eh_frame register number to DWARF register number, or
718 adjust .debug_frame register number. */
719 int (*adjust_regnum) (struct gdbarch *, int, int);
722 /* Default architecture-specific register state initialization
726 dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
727 struct dwarf2_frame_state_reg *reg,
728 struct frame_info *this_frame)
730 /* If we have a register that acts as a program counter, mark it as
731 a destination for the return address. If we have a register that
732 serves as the stack pointer, arrange for it to be filled with the
733 call frame address (CFA). The other registers are marked as
736 We copy the return address to the program counter, since many
737 parts in GDB assume that it is possible to get the return address
738 by unwinding the program counter register. However, on ISA's
739 with a dedicated return address register, the CFI usually only
740 contains information to unwind that return address register.
742 The reason we're treating the stack pointer special here is
743 because in many cases GCC doesn't emit CFI for the stack pointer
744 and implicitly assumes that it is equal to the CFA. This makes
745 some sense since the DWARF specification (version 3, draft 8,
748 "Typically, the CFA is defined to be the value of the stack
749 pointer at the call site in the previous frame (which may be
750 different from its value on entry to the current frame)."
752 However, this isn't true for all platforms supported by GCC
753 (e.g. IBM S/390 and zSeries). Those architectures should provide
754 their own architecture-specific initialization function. */
756 if (regnum == gdbarch_pc_regnum (gdbarch))
757 reg->how = DWARF2_FRAME_REG_RA;
758 else if (regnum == gdbarch_sp_regnum (gdbarch))
759 reg->how = DWARF2_FRAME_REG_CFA;
762 /* Return a default for the architecture-specific operations. */
765 dwarf2_frame_init (struct obstack *obstack)
767 struct dwarf2_frame_ops *ops;
769 ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
770 ops->init_reg = dwarf2_frame_default_init_reg;
774 /* Set the architecture-specific register state initialization
775 function for GDBARCH to INIT_REG. */
778 dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
779 void (*init_reg) (struct gdbarch *, int,
780 struct dwarf2_frame_state_reg *,
781 struct frame_info *))
783 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
785 ops->init_reg = init_reg;
788 /* Pre-initialize the register state REG for register REGNUM. */
791 dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
792 struct dwarf2_frame_state_reg *reg,
793 struct frame_info *this_frame)
795 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
797 ops->init_reg (gdbarch, regnum, reg, this_frame);
800 /* Set the architecture-specific signal trampoline recognition
801 function for GDBARCH to SIGNAL_FRAME_P. */
804 dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
805 int (*signal_frame_p) (struct gdbarch *,
806 struct frame_info *))
808 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
810 ops->signal_frame_p = signal_frame_p;
813 /* Query the architecture-specific signal frame recognizer for
817 dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
818 struct frame_info *this_frame)
820 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
822 if (ops->signal_frame_p == NULL)
824 return ops->signal_frame_p (gdbarch, this_frame);
827 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
831 dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
832 int (*adjust_regnum) (struct gdbarch *,
835 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
837 ops->adjust_regnum = adjust_regnum;
840 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
844 dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch,
845 int regnum, int eh_frame_p)
847 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
849 if (ops->adjust_regnum == NULL)
851 return ops->adjust_regnum (gdbarch, regnum, eh_frame_p);
855 dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
856 struct dwarf2_fde *fde)
860 s = find_pc_symtab (fs->pc);
864 if (producer_is_realview (s->producer))
866 if (fde->cie->version == 1)
867 fs->armcc_cfa_offsets_sf = 1;
869 if (fde->cie->version == 1)
870 fs->armcc_cfa_offsets_reversed = 1;
872 /* The reversed offset problem is present in some compilers
873 using DWARF3, but it was eventually fixed. Check the ARM
874 defined augmentations, which are in the format "armcc" followed
875 by a list of one-character options. The "+" option means
876 this problem is fixed (no quirk needed). If the armcc
877 augmentation is missing, the quirk is needed. */
878 if (fde->cie->version == 3
879 && (strncmp (fde->cie->augmentation, "armcc", 5) != 0
880 || strchr (fde->cie->augmentation + 5, '+') == NULL))
881 fs->armcc_cfa_offsets_reversed = 1;
889 dwarf2_compile_cfa_to_ax (struct agent_expr *expr, struct axs_value *loc,
890 struct gdbarch *gdbarch,
892 struct dwarf2_per_cu_data *data)
894 struct dwarf2_fde *fde;
895 CORE_ADDR text_offset;
896 struct dwarf2_frame_state fs;
899 memset (&fs, 0, sizeof (struct dwarf2_frame_state));
903 /* Find the correct FDE. */
904 fde = dwarf2_frame_find_fde (&fs.pc, &text_offset);
906 error (_("Could not compute CFA; needed to translate this expression"));
908 /* Extract any interesting information from the CIE. */
909 fs.data_align = fde->cie->data_alignment_factor;
910 fs.code_align = fde->cie->code_alignment_factor;
911 fs.retaddr_column = fde->cie->return_address_register;
912 addr_size = fde->cie->addr_size;
914 /* Check for "quirks" - known bugs in producers. */
915 dwarf2_frame_find_quirks (&fs, fde);
917 /* First decode all the insns in the CIE. */
918 execute_cfa_program (fde, fde->cie->initial_instructions,
919 fde->cie->end, gdbarch, pc, &fs);
921 /* Save the initialized register set. */
922 fs.initial = fs.regs;
923 fs.initial.reg = dwarf2_frame_state_copy_regs (&fs.regs);
925 /* Then decode the insns in the FDE up to our target PC. */
926 execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs);
928 /* Calculate the CFA. */
929 switch (fs.regs.cfa_how)
933 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, fs.regs.cfa_reg);
936 error (_("Unable to access DWARF register number %d"),
937 (int) fs.regs.cfa_reg); /* FIXME */
938 ax_reg (expr, regnum);
940 if (fs.regs.cfa_offset != 0)
942 if (fs.armcc_cfa_offsets_reversed)
943 ax_const_l (expr, -fs.regs.cfa_offset);
945 ax_const_l (expr, fs.regs.cfa_offset);
946 ax_simple (expr, aop_add);
952 ax_const_l (expr, text_offset);
953 dwarf2_compile_expr_to_ax (expr, loc, gdbarch, addr_size,
955 fs.regs.cfa_exp + fs.regs.cfa_exp_len,
960 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
965 struct dwarf2_frame_cache
967 /* DWARF Call Frame Address. */
970 /* Set if the return address column was marked as unavailable
971 (required non-collected memory or registers to compute). */
972 int unavailable_retaddr;
974 /* Set if the return address column was marked as undefined. */
975 int undefined_retaddr;
977 /* Saved registers, indexed by GDB register number, not by DWARF
979 struct dwarf2_frame_state_reg *reg;
981 /* Return address register. */
982 struct dwarf2_frame_state_reg retaddr_reg;
984 /* Target address size in bytes. */
987 /* The .text offset. */
988 CORE_ADDR text_offset;
990 /* True if we already checked whether this frame is the bottom frame
991 of a virtual tail call frame chain. */
992 int checked_tailcall_bottom;
994 /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME
995 sequence. If NULL then it is a normal case with no TAILCALL_FRAME
996 involved. Non-bottom frames of a virtual tail call frames chain use
997 dwarf2_tailcall_frame_unwind unwinder so this field does not apply for
999 void *tailcall_cache;
1001 /* The number of bytes to subtract from TAILCALL_FRAME frames frame
1002 base to get the SP, to simulate the return address pushed on the
1004 LONGEST entry_cfa_sp_offset;
1005 int entry_cfa_sp_offset_p;
1008 /* A cleanup that sets a pointer to NULL. */
1011 clear_pointer_cleanup (void *arg)
1018 static struct dwarf2_frame_cache *
1019 dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
1021 struct cleanup *reset_cache_cleanup, *old_chain;
1022 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1023 const int num_regs = gdbarch_num_regs (gdbarch)
1024 + gdbarch_num_pseudo_regs (gdbarch);
1025 struct dwarf2_frame_cache *cache;
1026 struct dwarf2_frame_state *fs;
1027 struct dwarf2_fde *fde;
1028 volatile struct gdb_exception ex;
1030 const gdb_byte *instr;
1035 /* Allocate a new cache. */
1036 cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
1037 cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
1038 *this_cache = cache;
1039 reset_cache_cleanup = make_cleanup (clear_pointer_cleanup, this_cache);
1041 /* Allocate and initialize the frame state. */
1042 fs = XCNEW (struct dwarf2_frame_state);
1043 old_chain = make_cleanup (dwarf2_frame_state_free, fs);
1047 Note that if the next frame is never supposed to return (i.e. a call
1048 to abort), the compiler might optimize away the instruction at
1049 its return address. As a result the return address will
1050 point at some random instruction, and the CFI for that
1051 instruction is probably worthless to us. GCC's unwinder solves
1052 this problem by substracting 1 from the return address to get an
1053 address in the middle of a presumed call instruction (or the
1054 instruction in the associated delay slot). This should only be
1055 done for "normal" frames and not for resume-type frames (signal
1056 handlers, sentinel frames, dummy frames). The function
1057 get_frame_address_in_block does just this. It's not clear how
1058 reliable the method is though; there is the potential for the
1059 register state pre-call being different to that on return. */
1060 fs->pc = get_frame_address_in_block (this_frame);
1062 /* Find the correct FDE. */
1063 fde = dwarf2_frame_find_fde (&fs->pc, &cache->text_offset);
1064 gdb_assert (fde != NULL);
1066 /* Extract any interesting information from the CIE. */
1067 fs->data_align = fde->cie->data_alignment_factor;
1068 fs->code_align = fde->cie->code_alignment_factor;
1069 fs->retaddr_column = fde->cie->return_address_register;
1070 cache->addr_size = fde->cie->addr_size;
1072 /* Check for "quirks" - known bugs in producers. */
1073 dwarf2_frame_find_quirks (fs, fde);
1075 /* First decode all the insns in the CIE. */
1076 execute_cfa_program (fde, fde->cie->initial_instructions,
1077 fde->cie->end, gdbarch,
1078 get_frame_address_in_block (this_frame), fs);
1080 /* Save the initialized register set. */
1081 fs->initial = fs->regs;
1082 fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs);
1084 if (get_frame_func_if_available (this_frame, &entry_pc))
1086 /* Decode the insns in the FDE up to the entry PC. */
1087 instr = execute_cfa_program (fde, fde->instructions, fde->end, gdbarch,
1090 if (fs->regs.cfa_how == CFA_REG_OFFSET
1091 && (gdbarch_dwarf2_reg_to_regnum (gdbarch, fs->regs.cfa_reg)
1092 == gdbarch_sp_regnum (gdbarch)))
1094 cache->entry_cfa_sp_offset = fs->regs.cfa_offset;
1095 cache->entry_cfa_sp_offset_p = 1;
1099 instr = fde->instructions;
1101 /* Then decode the insns in the FDE up to our target PC. */
1102 execute_cfa_program (fde, instr, fde->end, gdbarch,
1103 get_frame_address_in_block (this_frame), fs);
1105 TRY_CATCH (ex, RETURN_MASK_ERROR)
1107 /* Calculate the CFA. */
1108 switch (fs->regs.cfa_how)
1110 case CFA_REG_OFFSET:
1111 cache->cfa = read_addr_from_reg (this_frame, fs->regs.cfa_reg);
1112 if (fs->armcc_cfa_offsets_reversed)
1113 cache->cfa -= fs->regs.cfa_offset;
1115 cache->cfa += fs->regs.cfa_offset;
1120 execute_stack_op (fs->regs.cfa_exp, fs->regs.cfa_exp_len,
1121 cache->addr_size, cache->text_offset,
1126 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
1131 if (ex.error == NOT_AVAILABLE_ERROR)
1133 cache->unavailable_retaddr = 1;
1134 do_cleanups (old_chain);
1135 discard_cleanups (reset_cache_cleanup);
1139 throw_exception (ex);
1142 /* Initialize the register state. */
1146 for (regnum = 0; regnum < num_regs; regnum++)
1147 dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame);
1150 /* Go through the DWARF2 CFI generated table and save its register
1151 location information in the cache. Note that we don't skip the
1152 return address column; it's perfectly all right for it to
1153 correspond to a real register. If it doesn't correspond to a
1154 real register, or if we shouldn't treat it as such,
1155 gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside
1156 the range [0, gdbarch_num_regs). */
1158 int column; /* CFI speak for "register number". */
1160 for (column = 0; column < fs->regs.num_regs; column++)
1162 /* Use the GDB register number as the destination index. */
1163 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, column);
1165 /* If there's no corresponding GDB register, ignore it. */
1166 if (regnum < 0 || regnum >= num_regs)
1169 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1170 of all debug info registers. If it doesn't, complain (but
1171 not too loudly). It turns out that GCC assumes that an
1172 unspecified register implies "same value" when CFI (draft
1173 7) specifies nothing at all. Such a register could equally
1174 be interpreted as "undefined". Also note that this check
1175 isn't sufficient; it only checks that all registers in the
1176 range [0 .. max column] are specified, and won't detect
1177 problems when a debug info register falls outside of the
1178 table. We need a way of iterating through all the valid
1179 DWARF2 register numbers. */
1180 if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
1182 if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED)
1183 complaint (&symfile_complaints, _("\
1184 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1185 gdbarch_register_name (gdbarch, regnum),
1186 paddress (gdbarch, fs->pc));
1189 cache->reg[regnum] = fs->regs.reg[column];
1193 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1194 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1198 for (regnum = 0; regnum < num_regs; regnum++)
1200 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
1201 || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
1203 struct dwarf2_frame_state_reg *retaddr_reg =
1204 &fs->regs.reg[fs->retaddr_column];
1206 /* It seems rather bizarre to specify an "empty" column as
1207 the return adress column. However, this is exactly
1208 what GCC does on some targets. It turns out that GCC
1209 assumes that the return address can be found in the
1210 register corresponding to the return address column.
1211 Incidentally, that's how we should treat a return
1212 address column specifying "same value" too. */
1213 if (fs->retaddr_column < fs->regs.num_regs
1214 && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
1215 && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
1217 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1218 cache->reg[regnum] = *retaddr_reg;
1220 cache->retaddr_reg = *retaddr_reg;
1224 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1226 cache->reg[regnum].loc.reg = fs->retaddr_column;
1227 cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
1231 cache->retaddr_reg.loc.reg = fs->retaddr_column;
1232 cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG;
1239 if (fs->retaddr_column < fs->regs.num_regs
1240 && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
1241 cache->undefined_retaddr = 1;
1243 do_cleanups (old_chain);
1244 discard_cleanups (reset_cache_cleanup);
1248 static enum unwind_stop_reason
1249 dwarf2_frame_unwind_stop_reason (struct frame_info *this_frame,
1252 struct dwarf2_frame_cache *cache
1253 = dwarf2_frame_cache (this_frame, this_cache);
1255 if (cache->unavailable_retaddr)
1256 return UNWIND_UNAVAILABLE;
1258 if (cache->undefined_retaddr)
1259 return UNWIND_OUTERMOST;
1261 return UNWIND_NO_REASON;
1265 dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
1266 struct frame_id *this_id)
1268 struct dwarf2_frame_cache *cache =
1269 dwarf2_frame_cache (this_frame, this_cache);
1271 if (cache->unavailable_retaddr)
1272 (*this_id) = frame_id_build_unavailable_stack (get_frame_func (this_frame));
1273 else if (cache->undefined_retaddr)
1276 (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
1279 static struct value *
1280 dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache,
1283 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1284 struct dwarf2_frame_cache *cache =
1285 dwarf2_frame_cache (this_frame, this_cache);
1289 /* Check whether THIS_FRAME is the bottom frame of a virtual tail
1290 call frame chain. */
1291 if (!cache->checked_tailcall_bottom)
1293 cache->checked_tailcall_bottom = 1;
1294 dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache,
1295 (cache->entry_cfa_sp_offset_p
1296 ? &cache->entry_cfa_sp_offset : NULL));
1299 /* Non-bottom frames of a virtual tail call frames chain use
1300 dwarf2_tailcall_frame_unwind unwinder so this code does not apply for
1301 them. If dwarf2_tailcall_prev_register_first does not have specific value
1302 unwind the register, tail call frames are assumed to have the register set
1303 of the top caller. */
1304 if (cache->tailcall_cache)
1308 val = dwarf2_tailcall_prev_register_first (this_frame,
1309 &cache->tailcall_cache,
1315 switch (cache->reg[regnum].how)
1317 case DWARF2_FRAME_REG_UNDEFINED:
1318 /* If CFI explicitly specified that the value isn't defined,
1319 mark it as optimized away; the value isn't available. */
1320 return frame_unwind_got_optimized (this_frame, regnum);
1322 case DWARF2_FRAME_REG_SAVED_OFFSET:
1323 addr = cache->cfa + cache->reg[regnum].loc.offset;
1324 return frame_unwind_got_memory (this_frame, regnum, addr);
1326 case DWARF2_FRAME_REG_SAVED_REG:
1328 = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg);
1329 return frame_unwind_got_register (this_frame, regnum, realnum);
1331 case DWARF2_FRAME_REG_SAVED_EXP:
1332 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1333 cache->reg[regnum].exp_len,
1334 cache->addr_size, cache->text_offset,
1335 this_frame, cache->cfa, 1);
1336 return frame_unwind_got_memory (this_frame, regnum, addr);
1338 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET:
1339 addr = cache->cfa + cache->reg[regnum].loc.offset;
1340 return frame_unwind_got_constant (this_frame, regnum, addr);
1342 case DWARF2_FRAME_REG_SAVED_VAL_EXP:
1343 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1344 cache->reg[regnum].exp_len,
1345 cache->addr_size, cache->text_offset,
1346 this_frame, cache->cfa, 1);
1347 return frame_unwind_got_constant (this_frame, regnum, addr);
1349 case DWARF2_FRAME_REG_UNSPECIFIED:
1350 /* GCC, in its infinite wisdom decided to not provide unwind
1351 information for registers that are "same value". Since
1352 DWARF2 (3 draft 7) doesn't define such behavior, said
1353 registers are actually undefined (which is different to CFI
1354 "undefined"). Code above issues a complaint about this.
1355 Here just fudge the books, assume GCC, and that the value is
1356 more inner on the stack. */
1357 return frame_unwind_got_register (this_frame, regnum, regnum);
1359 case DWARF2_FRAME_REG_SAME_VALUE:
1360 return frame_unwind_got_register (this_frame, regnum, regnum);
1362 case DWARF2_FRAME_REG_CFA:
1363 return frame_unwind_got_address (this_frame, regnum, cache->cfa);
1365 case DWARF2_FRAME_REG_CFA_OFFSET:
1366 addr = cache->cfa + cache->reg[regnum].loc.offset;
1367 return frame_unwind_got_address (this_frame, regnum, addr);
1369 case DWARF2_FRAME_REG_RA_OFFSET:
1370 addr = cache->reg[regnum].loc.offset;
1371 regnum = gdbarch_dwarf2_reg_to_regnum
1372 (gdbarch, cache->retaddr_reg.loc.reg);
1373 addr += get_frame_register_unsigned (this_frame, regnum);
1374 return frame_unwind_got_address (this_frame, regnum, addr);
1376 case DWARF2_FRAME_REG_FN:
1377 return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum);
1380 internal_error (__FILE__, __LINE__, _("Unknown register rule."));
1384 /* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail
1385 call frames chain. */
1388 dwarf2_frame_dealloc_cache (struct frame_info *self, void *this_cache)
1390 struct dwarf2_frame_cache *cache = dwarf2_frame_cache (self, &this_cache);
1392 if (cache->tailcall_cache)
1393 dwarf2_tailcall_frame_unwind.dealloc_cache (self, cache->tailcall_cache);
1397 dwarf2_frame_sniffer (const struct frame_unwind *self,
1398 struct frame_info *this_frame, void **this_cache)
1400 /* Grab an address that is guarenteed to reside somewhere within the
1401 function. get_frame_pc(), with a no-return next function, can
1402 end up returning something past the end of this function's body.
1403 If the frame we're sniffing for is a signal frame whose start
1404 address is placed on the stack by the OS, its FDE must
1405 extend one byte before its start address or we could potentially
1406 select the FDE of the previous function. */
1407 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1408 struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr, NULL);
1413 /* On some targets, signal trampolines may have unwind information.
1414 We need to recognize them so that we set the frame type
1417 if (fde->cie->signal_frame
1418 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame),
1420 return self->type == SIGTRAMP_FRAME;
1422 if (self->type != NORMAL_FRAME)
1428 static const struct frame_unwind dwarf2_frame_unwind =
1431 dwarf2_frame_unwind_stop_reason,
1432 dwarf2_frame_this_id,
1433 dwarf2_frame_prev_register,
1435 dwarf2_frame_sniffer,
1436 dwarf2_frame_dealloc_cache
1439 static const struct frame_unwind dwarf2_signal_frame_unwind =
1442 dwarf2_frame_unwind_stop_reason,
1443 dwarf2_frame_this_id,
1444 dwarf2_frame_prev_register,
1446 dwarf2_frame_sniffer,
1448 /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */
1452 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1455 dwarf2_append_unwinders (struct gdbarch *gdbarch)
1457 /* TAILCALL_FRAME must be first to find the record by
1458 dwarf2_tailcall_sniffer_first. */
1459 frame_unwind_append_unwinder (gdbarch, &dwarf2_tailcall_frame_unwind);
1461 frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind);
1462 frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind);
1466 /* There is no explicitly defined relationship between the CFA and the
1467 location of frame's local variables and arguments/parameters.
1468 Therefore, frame base methods on this page should probably only be
1469 used as a last resort, just to avoid printing total garbage as a
1470 response to the "info frame" command. */
1473 dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache)
1475 struct dwarf2_frame_cache *cache =
1476 dwarf2_frame_cache (this_frame, this_cache);
1481 static const struct frame_base dwarf2_frame_base =
1483 &dwarf2_frame_unwind,
1484 dwarf2_frame_base_address,
1485 dwarf2_frame_base_address,
1486 dwarf2_frame_base_address
1489 const struct frame_base *
1490 dwarf2_frame_base_sniffer (struct frame_info *this_frame)
1492 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1494 if (dwarf2_frame_find_fde (&block_addr, NULL))
1495 return &dwarf2_frame_base;
1500 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1501 the DWARF unwinder. This is used to implement
1502 DW_OP_call_frame_cfa. */
1505 dwarf2_frame_cfa (struct frame_info *this_frame)
1507 if (frame_unwinder_is (this_frame, &record_btrace_tailcall_frame_unwind)
1508 || frame_unwinder_is (this_frame, &record_btrace_frame_unwind))
1509 throw_error (NOT_AVAILABLE_ERROR,
1510 _("cfa not available for record btrace target"));
1512 while (get_frame_type (this_frame) == INLINE_FRAME)
1513 this_frame = get_prev_frame (this_frame);
1514 if (get_frame_unwind_stop_reason (this_frame) == UNWIND_UNAVAILABLE)
1515 throw_error (NOT_AVAILABLE_ERROR,
1516 _("can't compute CFA for this frame: "
1517 "required registers or memory are unavailable"));
1518 /* This restriction could be lifted if other unwinders are known to
1519 compute the frame base in a way compatible with the DWARF
1521 if (!frame_unwinder_is (this_frame, &dwarf2_frame_unwind)
1522 && !frame_unwinder_is (this_frame, &dwarf2_tailcall_frame_unwind))
1523 error (_("can't compute CFA for this frame"));
1524 return get_frame_base (this_frame);
1527 const struct objfile_data *dwarf2_frame_objfile_data;
1530 read_1_byte (bfd *abfd, const gdb_byte *buf)
1532 return bfd_get_8 (abfd, buf);
1536 read_4_bytes (bfd *abfd, const gdb_byte *buf)
1538 return bfd_get_32 (abfd, buf);
1542 read_8_bytes (bfd *abfd, const gdb_byte *buf)
1544 return bfd_get_64 (abfd, buf);
1548 read_initial_length (bfd *abfd, const gdb_byte *buf,
1549 unsigned int *bytes_read_ptr)
1553 result = bfd_get_32 (abfd, buf);
1554 if (result == 0xffffffff)
1556 result = bfd_get_64 (abfd, buf + 4);
1557 *bytes_read_ptr = 12;
1560 *bytes_read_ptr = 4;
1566 /* Pointer encoding helper functions. */
1568 /* GCC supports exception handling based on DWARF2 CFI. However, for
1569 technical reasons, it encodes addresses in its FDE's in a different
1570 way. Several "pointer encodings" are supported. The encoding
1571 that's used for a particular FDE is determined by the 'R'
1572 augmentation in the associated CIE. The argument of this
1573 augmentation is a single byte.
1575 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1576 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1577 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1578 address should be interpreted (absolute, relative to the current
1579 position in the FDE, ...). Bit 7, indicates that the address
1580 should be dereferenced. */
1583 encoding_for_size (unsigned int size)
1588 return DW_EH_PE_udata2;
1590 return DW_EH_PE_udata4;
1592 return DW_EH_PE_udata8;
1594 internal_error (__FILE__, __LINE__, _("Unsupported address size"));
1599 read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
1600 int ptr_len, const gdb_byte *buf,
1601 unsigned int *bytes_read_ptr,
1602 CORE_ADDR func_base)
1607 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1609 if (encoding & DW_EH_PE_indirect)
1610 internal_error (__FILE__, __LINE__,
1611 _("Unsupported encoding: DW_EH_PE_indirect"));
1613 *bytes_read_ptr = 0;
1615 switch (encoding & 0x70)
1617 case DW_EH_PE_absptr:
1620 case DW_EH_PE_pcrel:
1621 base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section);
1622 base += (buf - unit->dwarf_frame_buffer);
1624 case DW_EH_PE_datarel:
1627 case DW_EH_PE_textrel:
1630 case DW_EH_PE_funcrel:
1633 case DW_EH_PE_aligned:
1635 offset = buf - unit->dwarf_frame_buffer;
1636 if ((offset % ptr_len) != 0)
1638 *bytes_read_ptr = ptr_len - (offset % ptr_len);
1639 buf += *bytes_read_ptr;
1643 internal_error (__FILE__, __LINE__,
1644 _("Invalid or unsupported encoding"));
1647 if ((encoding & 0x07) == 0x00)
1649 encoding |= encoding_for_size (ptr_len);
1650 if (bfd_get_sign_extend_vma (unit->abfd))
1651 encoding |= DW_EH_PE_signed;
1654 switch (encoding & 0x0f)
1656 case DW_EH_PE_uleb128:
1659 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1661 *bytes_read_ptr += safe_read_uleb128 (buf, end_buf, &value) - buf;
1662 return base + value;
1664 case DW_EH_PE_udata2:
1665 *bytes_read_ptr += 2;
1666 return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf));
1667 case DW_EH_PE_udata4:
1668 *bytes_read_ptr += 4;
1669 return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf));
1670 case DW_EH_PE_udata8:
1671 *bytes_read_ptr += 8;
1672 return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf));
1673 case DW_EH_PE_sleb128:
1676 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1678 *bytes_read_ptr += safe_read_sleb128 (buf, end_buf, &value) - buf;
1679 return base + value;
1681 case DW_EH_PE_sdata2:
1682 *bytes_read_ptr += 2;
1683 return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf));
1684 case DW_EH_PE_sdata4:
1685 *bytes_read_ptr += 4;
1686 return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf));
1687 case DW_EH_PE_sdata8:
1688 *bytes_read_ptr += 8;
1689 return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf));
1691 internal_error (__FILE__, __LINE__,
1692 _("Invalid or unsupported encoding"));
1698 bsearch_cie_cmp (const void *key, const void *element)
1700 ULONGEST cie_pointer = *(ULONGEST *) key;
1701 struct dwarf2_cie *cie = *(struct dwarf2_cie **) element;
1703 if (cie_pointer == cie->cie_pointer)
1706 return (cie_pointer < cie->cie_pointer) ? -1 : 1;
1709 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1710 static struct dwarf2_cie *
1711 find_cie (struct dwarf2_cie_table *cie_table, ULONGEST cie_pointer)
1713 struct dwarf2_cie **p_cie;
1715 /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
1716 bsearch be non-NULL. */
1717 if (cie_table->entries == NULL)
1719 gdb_assert (cie_table->num_entries == 0);
1723 p_cie = bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries,
1724 sizeof (cie_table->entries[0]), bsearch_cie_cmp);
1730 /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1732 add_cie (struct dwarf2_cie_table *cie_table, struct dwarf2_cie *cie)
1734 const int n = cie_table->num_entries;
1737 || cie_table->entries[n - 1]->cie_pointer < cie->cie_pointer);
1739 cie_table->entries =
1740 xrealloc (cie_table->entries, (n + 1) * sizeof (cie_table->entries[0]));
1741 cie_table->entries[n] = cie;
1742 cie_table->num_entries = n + 1;
1746 bsearch_fde_cmp (const void *key, const void *element)
1748 CORE_ADDR seek_pc = *(CORE_ADDR *) key;
1749 struct dwarf2_fde *fde = *(struct dwarf2_fde **) element;
1751 if (seek_pc < fde->initial_location)
1753 if (seek_pc < fde->initial_location + fde->address_range)
1758 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1759 inital location associated with it into *PC. */
1761 static struct dwarf2_fde *
1762 dwarf2_frame_find_fde (CORE_ADDR *pc, CORE_ADDR *out_offset)
1764 struct objfile *objfile;
1766 ALL_OBJFILES (objfile)
1768 struct dwarf2_fde_table *fde_table;
1769 struct dwarf2_fde **p_fde;
1773 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1774 if (fde_table == NULL)
1776 dwarf2_build_frame_info (objfile);
1777 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1779 gdb_assert (fde_table != NULL);
1781 if (fde_table->num_entries == 0)
1784 gdb_assert (objfile->section_offsets);
1785 offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
1787 gdb_assert (fde_table->num_entries > 0);
1788 if (*pc < offset + fde_table->entries[0]->initial_location)
1791 seek_pc = *pc - offset;
1792 p_fde = bsearch (&seek_pc, fde_table->entries, fde_table->num_entries,
1793 sizeof (fde_table->entries[0]), bsearch_fde_cmp);
1796 *pc = (*p_fde)->initial_location + offset;
1798 *out_offset = offset;
1805 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1807 add_fde (struct dwarf2_fde_table *fde_table, struct dwarf2_fde *fde)
1809 if (fde->address_range == 0)
1810 /* Discard useless FDEs. */
1813 fde_table->num_entries += 1;
1814 fde_table->entries =
1815 xrealloc (fde_table->entries,
1816 fde_table->num_entries * sizeof (fde_table->entries[0]));
1817 fde_table->entries[fde_table->num_entries - 1] = fde;
1820 #define DW64_CIE_ID 0xffffffffffffffffULL
1822 /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
1827 EH_CIE_TYPE_ID = 1 << 0,
1828 EH_FDE_TYPE_ID = 1 << 1,
1829 EH_CIE_OR_FDE_TYPE_ID = EH_CIE_TYPE_ID | EH_FDE_TYPE_ID
1832 static const gdb_byte *decode_frame_entry (struct comp_unit *unit,
1833 const gdb_byte *start,
1835 struct dwarf2_cie_table *cie_table,
1836 struct dwarf2_fde_table *fde_table,
1837 enum eh_frame_type entry_type);
1839 /* Decode the next CIE or FDE, entry_type specifies the expected type.
1840 Return NULL if invalid input, otherwise the next byte to be processed. */
1842 static const gdb_byte *
1843 decode_frame_entry_1 (struct comp_unit *unit, const gdb_byte *start,
1845 struct dwarf2_cie_table *cie_table,
1846 struct dwarf2_fde_table *fde_table,
1847 enum eh_frame_type entry_type)
1849 struct gdbarch *gdbarch = get_objfile_arch (unit->objfile);
1850 const gdb_byte *buf, *end;
1852 unsigned int bytes_read;
1855 ULONGEST cie_pointer;
1860 length = read_initial_length (unit->abfd, buf, &bytes_read);
1864 /* Are we still within the section? */
1865 if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
1871 /* Distinguish between 32 and 64-bit encoded frame info. */
1872 dwarf64_p = (bytes_read == 12);
1874 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1878 cie_id = DW64_CIE_ID;
1884 cie_pointer = read_8_bytes (unit->abfd, buf);
1889 cie_pointer = read_4_bytes (unit->abfd, buf);
1893 if (cie_pointer == cie_id)
1895 /* This is a CIE. */
1896 struct dwarf2_cie *cie;
1898 unsigned int cie_version;
1900 /* Check that a CIE was expected. */
1901 if ((entry_type & EH_CIE_TYPE_ID) == 0)
1902 error (_("Found a CIE when not expecting it."));
1904 /* Record the offset into the .debug_frame section of this CIE. */
1905 cie_pointer = start - unit->dwarf_frame_buffer;
1907 /* Check whether we've already read it. */
1908 if (find_cie (cie_table, cie_pointer))
1911 cie = (struct dwarf2_cie *)
1912 obstack_alloc (&unit->objfile->objfile_obstack,
1913 sizeof (struct dwarf2_cie));
1914 cie->initial_instructions = NULL;
1915 cie->cie_pointer = cie_pointer;
1917 /* The encoding for FDE's in a normal .debug_frame section
1918 depends on the target address size. */
1919 cie->encoding = DW_EH_PE_absptr;
1921 /* We'll determine the final value later, but we need to
1922 initialize it conservatively. */
1923 cie->signal_frame = 0;
1925 /* Check version number. */
1926 cie_version = read_1_byte (unit->abfd, buf);
1927 if (cie_version != 1 && cie_version != 3 && cie_version != 4)
1929 cie->version = cie_version;
1932 /* Interpret the interesting bits of the augmentation. */
1933 cie->augmentation = augmentation = (char *) buf;
1934 buf += (strlen (augmentation) + 1);
1936 /* Ignore armcc augmentations. We only use them for quirks,
1937 and that doesn't happen until later. */
1938 if (strncmp (augmentation, "armcc", 5) == 0)
1939 augmentation += strlen (augmentation);
1941 /* The GCC 2.x "eh" augmentation has a pointer immediately
1942 following the augmentation string, so it must be handled
1944 if (augmentation[0] == 'e' && augmentation[1] == 'h')
1947 buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1951 if (cie->version >= 4)
1953 /* FIXME: check that this is the same as from the CU header. */
1954 cie->addr_size = read_1_byte (unit->abfd, buf);
1956 cie->segment_size = read_1_byte (unit->abfd, buf);
1961 cie->addr_size = gdbarch_dwarf2_addr_size (gdbarch);
1962 cie->segment_size = 0;
1964 /* Address values in .eh_frame sections are defined to have the
1965 target's pointer size. Watchout: This breaks frame info for
1966 targets with pointer size < address size, unless a .debug_frame
1967 section exists as well. */
1969 cie->ptr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1971 cie->ptr_size = cie->addr_size;
1973 buf = gdb_read_uleb128 (buf, end, &uleb128);
1976 cie->code_alignment_factor = uleb128;
1978 buf = gdb_read_sleb128 (buf, end, &sleb128);
1981 cie->data_alignment_factor = sleb128;
1983 if (cie_version == 1)
1985 cie->return_address_register = read_1_byte (unit->abfd, buf);
1990 buf = gdb_read_uleb128 (buf, end, &uleb128);
1993 cie->return_address_register = uleb128;
1996 cie->return_address_register
1997 = dwarf2_frame_adjust_regnum (gdbarch,
1998 cie->return_address_register,
2001 cie->saw_z_augmentation = (*augmentation == 'z');
2002 if (cie->saw_z_augmentation)
2006 buf = gdb_read_uleb128 (buf, end, &length);
2009 cie->initial_instructions = buf + length;
2013 while (*augmentation)
2015 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
2016 if (*augmentation == 'L')
2023 /* "R" indicates a byte indicating how FDE addresses are encoded. */
2024 else if (*augmentation == 'R')
2026 cie->encoding = *buf++;
2030 /* "P" indicates a personality routine in the CIE augmentation. */
2031 else if (*augmentation == 'P')
2033 /* Skip. Avoid indirection since we throw away the result. */
2034 gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect;
2035 read_encoded_value (unit, encoding, cie->ptr_size,
2036 buf, &bytes_read, 0);
2041 /* "S" indicates a signal frame, such that the return
2042 address must not be decremented to locate the call frame
2043 info for the previous frame; it might even be the first
2044 instruction of a function, so decrementing it would take
2045 us to a different function. */
2046 else if (*augmentation == 'S')
2048 cie->signal_frame = 1;
2052 /* Otherwise we have an unknown augmentation. Assume that either
2053 there is no augmentation data, or we saw a 'z' prefix. */
2056 if (cie->initial_instructions)
2057 buf = cie->initial_instructions;
2062 cie->initial_instructions = buf;
2066 add_cie (cie_table, cie);
2070 /* This is a FDE. */
2071 struct dwarf2_fde *fde;
2073 /* Check that an FDE was expected. */
2074 if ((entry_type & EH_FDE_TYPE_ID) == 0)
2075 error (_("Found an FDE when not expecting it."));
2077 /* In an .eh_frame section, the CIE pointer is the delta between the
2078 address within the FDE where the CIE pointer is stored and the
2079 address of the CIE. Convert it to an offset into the .eh_frame
2083 cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
2084 cie_pointer -= (dwarf64_p ? 8 : 4);
2087 /* In either case, validate the result is still within the section. */
2088 if (cie_pointer >= unit->dwarf_frame_size)
2091 fde = (struct dwarf2_fde *)
2092 obstack_alloc (&unit->objfile->objfile_obstack,
2093 sizeof (struct dwarf2_fde));
2094 fde->cie = find_cie (cie_table, cie_pointer);
2095 if (fde->cie == NULL)
2097 decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer,
2098 eh_frame_p, cie_table, fde_table,
2100 fde->cie = find_cie (cie_table, cie_pointer);
2103 gdb_assert (fde->cie != NULL);
2105 fde->initial_location =
2106 read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size,
2107 buf, &bytes_read, 0);
2110 fde->address_range =
2111 read_encoded_value (unit, fde->cie->encoding & 0x0f,
2112 fde->cie->ptr_size, buf, &bytes_read, 0);
2115 /* A 'z' augmentation in the CIE implies the presence of an
2116 augmentation field in the FDE as well. The only thing known
2117 to be in here at present is the LSDA entry for EH. So we
2118 can skip the whole thing. */
2119 if (fde->cie->saw_z_augmentation)
2123 buf = gdb_read_uleb128 (buf, end, &length);
2131 fde->instructions = buf;
2134 fde->eh_frame_p = eh_frame_p;
2136 add_fde (fde_table, fde);
2142 /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
2143 expect an FDE or a CIE. */
2145 static const gdb_byte *
2146 decode_frame_entry (struct comp_unit *unit, const gdb_byte *start,
2148 struct dwarf2_cie_table *cie_table,
2149 struct dwarf2_fde_table *fde_table,
2150 enum eh_frame_type entry_type)
2152 enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
2153 const gdb_byte *ret;
2154 ptrdiff_t start_offset;
2158 ret = decode_frame_entry_1 (unit, start, eh_frame_p,
2159 cie_table, fde_table, entry_type);
2163 /* We have corrupt input data of some form. */
2165 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
2166 and mismatches wrt padding and alignment of debug sections. */
2167 /* Note that there is no requirement in the standard for any
2168 alignment at all in the frame unwind sections. Testing for
2169 alignment before trying to interpret data would be incorrect.
2171 However, GCC traditionally arranged for frame sections to be
2172 sized such that the FDE length and CIE fields happen to be
2173 aligned (in theory, for performance). This, unfortunately,
2174 was done with .align directives, which had the side effect of
2175 forcing the section to be aligned by the linker.
2177 This becomes a problem when you have some other producer that
2178 creates frame sections that are not as strictly aligned. That
2179 produces a hole in the frame info that gets filled by the
2182 The GCC behaviour is arguably a bug, but it's effectively now
2183 part of the ABI, so we're now stuck with it, at least at the
2184 object file level. A smart linker may decide, in the process
2185 of compressing duplicate CIE information, that it can rewrite
2186 the entire output section without this extra padding. */
2188 start_offset = start - unit->dwarf_frame_buffer;
2189 if (workaround < ALIGN4 && (start_offset & 3) != 0)
2191 start += 4 - (start_offset & 3);
2192 workaround = ALIGN4;
2195 if (workaround < ALIGN8 && (start_offset & 7) != 0)
2197 start += 8 - (start_offset & 7);
2198 workaround = ALIGN8;
2202 /* Nothing left to try. Arrange to return as if we've consumed
2203 the entire input section. Hopefully we'll get valid info from
2204 the other of .debug_frame/.eh_frame. */
2206 ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
2216 complaint (&symfile_complaints, _("\
2217 Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
2218 unit->dwarf_frame_section->owner->filename,
2219 unit->dwarf_frame_section->name);
2223 complaint (&symfile_complaints, _("\
2224 Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
2225 unit->dwarf_frame_section->owner->filename,
2226 unit->dwarf_frame_section->name);
2230 complaint (&symfile_complaints,
2231 _("Corrupt data in %s:%s"),
2232 unit->dwarf_frame_section->owner->filename,
2233 unit->dwarf_frame_section->name);
2241 qsort_fde_cmp (const void *a, const void *b)
2243 struct dwarf2_fde *aa = *(struct dwarf2_fde **)a;
2244 struct dwarf2_fde *bb = *(struct dwarf2_fde **)b;
2246 if (aa->initial_location == bb->initial_location)
2248 if (aa->address_range != bb->address_range
2249 && aa->eh_frame_p == 0 && bb->eh_frame_p == 0)
2250 /* Linker bug, e.g. gold/10400.
2251 Work around it by keeping stable sort order. */
2252 return (a < b) ? -1 : 1;
2254 /* Put eh_frame entries after debug_frame ones. */
2255 return aa->eh_frame_p - bb->eh_frame_p;
2258 return (aa->initial_location < bb->initial_location) ? -1 : 1;
2262 dwarf2_build_frame_info (struct objfile *objfile)
2264 struct comp_unit *unit;
2265 const gdb_byte *frame_ptr;
2266 struct dwarf2_cie_table cie_table;
2267 struct dwarf2_fde_table fde_table;
2268 struct dwarf2_fde_table *fde_table2;
2269 volatile struct gdb_exception e;
2271 cie_table.num_entries = 0;
2272 cie_table.entries = NULL;
2274 fde_table.num_entries = 0;
2275 fde_table.entries = NULL;
2277 /* Build a minimal decoding of the DWARF2 compilation unit. */
2278 unit = (struct comp_unit *) obstack_alloc (&objfile->objfile_obstack,
2279 sizeof (struct comp_unit));
2280 unit->abfd = objfile->obfd;
2281 unit->objfile = objfile;
2285 if (objfile->separate_debug_objfile_backlink == NULL)
2287 /* Do not read .eh_frame from separate file as they must be also
2288 present in the main file. */
2289 dwarf2_get_section_info (objfile, DWARF2_EH_FRAME,
2290 &unit->dwarf_frame_section,
2291 &unit->dwarf_frame_buffer,
2292 &unit->dwarf_frame_size);
2293 if (unit->dwarf_frame_size)
2295 asection *got, *txt;
2297 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2298 that is used for the i386/amd64 target, which currently is
2299 the only target in GCC that supports/uses the
2300 DW_EH_PE_datarel encoding. */
2301 got = bfd_get_section_by_name (unit->abfd, ".got");
2303 unit->dbase = got->vma;
2305 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2307 txt = bfd_get_section_by_name (unit->abfd, ".text");
2309 unit->tbase = txt->vma;
2311 TRY_CATCH (e, RETURN_MASK_ERROR)
2313 frame_ptr = unit->dwarf_frame_buffer;
2314 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2315 frame_ptr = decode_frame_entry (unit, frame_ptr, 1,
2316 &cie_table, &fde_table,
2317 EH_CIE_OR_FDE_TYPE_ID);
2322 warning (_("skipping .eh_frame info of %s: %s"),
2323 objfile_name (objfile), e.message);
2325 if (fde_table.num_entries != 0)
2327 xfree (fde_table.entries);
2328 fde_table.entries = NULL;
2329 fde_table.num_entries = 0;
2331 /* The cie_table is discarded by the next if. */
2334 if (cie_table.num_entries != 0)
2336 /* Reinit cie_table: debug_frame has different CIEs. */
2337 xfree (cie_table.entries);
2338 cie_table.num_entries = 0;
2339 cie_table.entries = NULL;
2344 dwarf2_get_section_info (objfile, DWARF2_DEBUG_FRAME,
2345 &unit->dwarf_frame_section,
2346 &unit->dwarf_frame_buffer,
2347 &unit->dwarf_frame_size);
2348 if (unit->dwarf_frame_size)
2350 int num_old_fde_entries = fde_table.num_entries;
2352 TRY_CATCH (e, RETURN_MASK_ERROR)
2354 frame_ptr = unit->dwarf_frame_buffer;
2355 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2356 frame_ptr = decode_frame_entry (unit, frame_ptr, 0,
2357 &cie_table, &fde_table,
2358 EH_CIE_OR_FDE_TYPE_ID);
2362 warning (_("skipping .debug_frame info of %s: %s"),
2363 objfile_name (objfile), e.message);
2365 if (fde_table.num_entries != 0)
2367 fde_table.num_entries = num_old_fde_entries;
2368 if (num_old_fde_entries == 0)
2370 xfree (fde_table.entries);
2371 fde_table.entries = NULL;
2375 fde_table.entries = xrealloc (fde_table.entries,
2376 fde_table.num_entries *
2377 sizeof (fde_table.entries[0]));
2380 fde_table.num_entries = num_old_fde_entries;
2381 /* The cie_table is discarded by the next if. */
2385 /* Discard the cie_table, it is no longer needed. */
2386 if (cie_table.num_entries != 0)
2388 xfree (cie_table.entries);
2389 cie_table.entries = NULL; /* Paranoia. */
2390 cie_table.num_entries = 0; /* Paranoia. */
2393 /* Copy fde_table to obstack: it is needed at runtime. */
2394 fde_table2 = (struct dwarf2_fde_table *)
2395 obstack_alloc (&objfile->objfile_obstack, sizeof (*fde_table2));
2397 if (fde_table.num_entries == 0)
2399 fde_table2->entries = NULL;
2400 fde_table2->num_entries = 0;
2404 struct dwarf2_fde *fde_prev = NULL;
2405 struct dwarf2_fde *first_non_zero_fde = NULL;
2408 /* Prepare FDE table for lookups. */
2409 qsort (fde_table.entries, fde_table.num_entries,
2410 sizeof (fde_table.entries[0]), qsort_fde_cmp);
2412 /* Check for leftovers from --gc-sections. The GNU linker sets
2413 the relevant symbols to zero, but doesn't zero the FDE *end*
2414 ranges because there's no relocation there. It's (offset,
2415 length), not (start, end). On targets where address zero is
2416 just another valid address this can be a problem, since the
2417 FDEs appear to be non-empty in the output --- we could pick
2418 out the wrong FDE. To work around this, when overlaps are
2419 detected, we prefer FDEs that do not start at zero.
2421 Start by finding the first FDE with non-zero start. Below
2422 we'll discard all FDEs that start at zero and overlap this
2424 for (i = 0; i < fde_table.num_entries; i++)
2426 struct dwarf2_fde *fde = fde_table.entries[i];
2428 if (fde->initial_location != 0)
2430 first_non_zero_fde = fde;
2435 /* Since we'll be doing bsearch, squeeze out identical (except
2436 for eh_frame_p) fde entries so bsearch result is predictable.
2437 Also discard leftovers from --gc-sections. */
2438 fde_table2->num_entries = 0;
2439 for (i = 0; i < fde_table.num_entries; i++)
2441 struct dwarf2_fde *fde = fde_table.entries[i];
2443 if (fde->initial_location == 0
2444 && first_non_zero_fde != NULL
2445 && (first_non_zero_fde->initial_location
2446 < fde->initial_location + fde->address_range))
2449 if (fde_prev != NULL
2450 && fde_prev->initial_location == fde->initial_location)
2453 obstack_grow (&objfile->objfile_obstack, &fde_table.entries[i],
2454 sizeof (fde_table.entries[0]));
2455 ++fde_table2->num_entries;
2458 fde_table2->entries = obstack_finish (&objfile->objfile_obstack);
2460 /* Discard the original fde_table. */
2461 xfree (fde_table.entries);
2464 set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2);
2467 /* Provide a prototype to silence -Wmissing-prototypes. */
2468 void _initialize_dwarf2_frame (void);
2471 _initialize_dwarf2_frame (void)
2473 dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
2474 dwarf2_frame_objfile_data = register_objfile_data ();