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"
36 #include "complaints.h"
37 #include "dwarf2-frame.h"
39 #include "dwarf2loc.h"
40 #include "dwarf2-frame-tailcall.h"
44 /* Call Frame Information (CFI). */
46 /* Common Information Entry (CIE). */
50 /* Computation Unit for this CIE. */
51 struct comp_unit *unit;
53 /* Offset into the .debug_frame section where this CIE was found.
54 Used to identify this CIE. */
57 /* Constant that is factored out of all advance location
59 ULONGEST code_alignment_factor;
61 /* Constants that is factored out of all offset instructions. */
62 LONGEST data_alignment_factor;
64 /* Return address column. */
65 ULONGEST return_address_register;
67 /* Instruction sequence to initialize a register set. */
68 const gdb_byte *initial_instructions;
71 /* Saved augmentation, in case it's needed later. */
74 /* Encoding of addresses. */
77 /* Target address size in bytes. */
80 /* Target pointer size in bytes. */
83 /* True if a 'z' augmentation existed. */
84 unsigned char saw_z_augmentation;
86 /* True if an 'S' augmentation existed. */
87 unsigned char signal_frame;
89 /* The version recorded in the CIE. */
90 unsigned char version;
92 /* The segment size. */
93 unsigned char segment_size;
96 struct dwarf2_cie_table
99 struct dwarf2_cie **entries;
102 /* Frame Description Entry (FDE). */
106 /* CIE for this FDE. */
107 struct dwarf2_cie *cie;
109 /* First location associated with this FDE. */
110 CORE_ADDR initial_location;
112 /* Number of bytes of program instructions described by this FDE. */
113 CORE_ADDR address_range;
115 /* Instruction sequence. */
116 const gdb_byte *instructions;
119 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
121 unsigned char eh_frame_p;
124 struct dwarf2_fde_table
127 struct dwarf2_fde **entries;
130 /* A minimal decoding of DWARF2 compilation units. We only decode
131 what's needed to get to the call frame information. */
135 /* Keep the bfd convenient. */
138 struct objfile *objfile;
140 /* Pointer to the .debug_frame section loaded into memory. */
141 const gdb_byte *dwarf_frame_buffer;
143 /* Length of the loaded .debug_frame section. */
144 bfd_size_type dwarf_frame_size;
146 /* Pointer to the .debug_frame section. */
147 asection *dwarf_frame_section;
149 /* Base for DW_EH_PE_datarel encodings. */
152 /* Base for DW_EH_PE_textrel encodings. */
156 static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc,
157 CORE_ADDR *out_offset);
159 static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum,
162 static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
163 int ptr_len, const gdb_byte *buf,
164 unsigned int *bytes_read_ptr,
165 CORE_ADDR func_base);
168 /* Structure describing a frame state. */
170 struct dwarf2_frame_state
172 /* Each register save state can be described in terms of a CFA slot,
173 another register, or a location expression. */
174 struct dwarf2_frame_state_reg_info
176 struct dwarf2_frame_state_reg *reg;
186 const gdb_byte *cfa_exp;
188 /* Used to implement DW_CFA_remember_state. */
189 struct dwarf2_frame_state_reg_info *prev;
192 /* The PC described by the current frame state. */
195 /* Initial register set from the CIE.
196 Used to implement DW_CFA_restore. */
197 struct dwarf2_frame_state_reg_info initial;
199 /* The information we care about from the CIE. */
202 ULONGEST retaddr_column;
204 /* Flags for known producer quirks. */
206 /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa
207 and DW_CFA_def_cfa_offset takes a factored offset. */
208 int armcc_cfa_offsets_sf;
210 /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
211 the CFA is defined as REG - OFFSET rather than REG + OFFSET. */
212 int armcc_cfa_offsets_reversed;
215 /* Store the length the expression for the CFA in the `cfa_reg' field,
216 which is unused in that case. */
217 #define cfa_exp_len cfa_reg
219 /* Assert that the register set RS is large enough to store gdbarch_num_regs
220 columns. If necessary, enlarge the register set. */
223 dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs,
226 size_t size = sizeof (struct dwarf2_frame_state_reg);
228 if (num_regs <= rs->num_regs)
231 rs->reg = (struct dwarf2_frame_state_reg *)
232 xrealloc (rs->reg, num_regs * size);
234 /* Initialize newly allocated registers. */
235 memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size);
236 rs->num_regs = num_regs;
239 /* Copy the register columns in register set RS into newly allocated
240 memory and return a pointer to this newly created copy. */
242 static struct dwarf2_frame_state_reg *
243 dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs)
245 size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg);
246 struct dwarf2_frame_state_reg *reg;
248 reg = (struct dwarf2_frame_state_reg *) xmalloc (size);
249 memcpy (reg, rs->reg, size);
254 /* Release the memory allocated to register set RS. */
257 dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs)
261 dwarf2_frame_state_free_regs (rs->prev);
268 /* Release the memory allocated to the frame state FS. */
271 dwarf2_frame_state_free (void *p)
273 struct dwarf2_frame_state *fs = p;
275 dwarf2_frame_state_free_regs (fs->initial.prev);
276 dwarf2_frame_state_free_regs (fs->regs.prev);
277 xfree (fs->initial.reg);
278 xfree (fs->regs.reg);
283 /* Helper functions for execute_stack_op. */
286 read_addr_from_reg (void *baton, int reg)
288 struct frame_info *this_frame = (struct frame_info *) baton;
289 struct gdbarch *gdbarch = get_frame_arch (this_frame);
290 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
292 return address_from_register (regnum, this_frame);
295 /* Implement struct dwarf_expr_context_funcs' "get_reg_value" callback. */
297 static struct value *
298 get_reg_value (void *baton, struct type *type, int reg)
300 struct frame_info *this_frame = (struct frame_info *) baton;
301 struct gdbarch *gdbarch = get_frame_arch (this_frame);
302 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
304 return value_from_register (type, regnum, this_frame);
308 read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
310 read_memory (addr, buf, len);
313 /* Execute the required actions for both the DW_CFA_restore and
314 DW_CFA_restore_extended instructions. */
316 dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
317 struct dwarf2_frame_state *fs, int eh_frame_p)
321 gdb_assert (fs->initial.reg);
322 reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
323 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
325 /* Check if this register was explicitly initialized in the
326 CIE initial instructions. If not, default the rule to
328 if (reg < fs->initial.num_regs)
329 fs->regs.reg[reg] = fs->initial.reg[reg];
331 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;
333 if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED)
334 complaint (&symfile_complaints, _("\
335 incomplete CFI data; DW_CFA_restore unspecified\n\
336 register %s (#%d) at %s"),
337 gdbarch_register_name
338 (gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)),
339 gdbarch_dwarf2_reg_to_regnum (gdbarch, reg),
340 paddress (gdbarch, fs->pc));
343 /* Virtual method table for execute_stack_op below. */
345 static const struct dwarf_expr_context_funcs dwarf2_frame_ctx_funcs =
350 ctx_no_get_frame_base,
351 ctx_no_get_frame_cfa,
353 ctx_no_get_tls_address,
355 ctx_no_get_base_type,
356 ctx_no_push_dwarf_reg_entry_value,
357 ctx_no_get_addr_index
361 execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
362 CORE_ADDR offset, struct frame_info *this_frame,
363 CORE_ADDR initial, int initial_in_stack_memory)
365 struct dwarf_expr_context *ctx;
367 struct cleanup *old_chain;
369 ctx = new_dwarf_expr_context ();
370 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
371 make_cleanup_value_free_to_mark (value_mark ());
373 ctx->gdbarch = get_frame_arch (this_frame);
374 ctx->addr_size = addr_size;
375 ctx->ref_addr_size = -1;
376 ctx->offset = offset;
377 ctx->baton = this_frame;
378 ctx->funcs = &dwarf2_frame_ctx_funcs;
380 dwarf_expr_push_address (ctx, initial, initial_in_stack_memory);
381 dwarf_expr_eval (ctx, exp, len);
383 if (ctx->location == DWARF_VALUE_MEMORY)
384 result = dwarf_expr_fetch_address (ctx, 0);
385 else if (ctx->location == DWARF_VALUE_REGISTER)
386 result = read_addr_from_reg (this_frame,
387 value_as_long (dwarf_expr_fetch (ctx, 0)));
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. */
394 Not implemented: computing unwound register using explicit value operator"));
397 do_cleanups (old_chain);
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. */
407 static const gdb_byte *
408 execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,
409 const gdb_byte *insn_end, struct gdbarch *gdbarch,
410 CORE_ADDR pc, struct dwarf2_frame_state *fs)
412 int eh_frame_p = fde->eh_frame_p;
413 unsigned int bytes_read;
414 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
416 while (insn_ptr < insn_end && fs->pc <= pc)
418 gdb_byte insn = *insn_ptr++;
422 if ((insn & 0xc0) == DW_CFA_advance_loc)
423 fs->pc += (insn & 0x3f) * fs->code_align;
424 else if ((insn & 0xc0) == DW_CFA_offset)
427 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
428 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
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;
434 else if ((insn & 0xc0) == DW_CFA_restore)
437 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
444 fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
445 fde->cie->ptr_size, insn_ptr,
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;
453 case DW_CFA_advance_loc1:
454 utmp = extract_unsigned_integer (insn_ptr, 1, byte_order);
455 fs->pc += utmp * fs->code_align;
458 case DW_CFA_advance_loc2:
459 utmp = extract_unsigned_integer (insn_ptr, 2, byte_order);
460 fs->pc += utmp * fs->code_align;
463 case DW_CFA_advance_loc4:
464 utmp = extract_unsigned_integer (insn_ptr, 4, byte_order);
465 fs->pc += utmp * fs->code_align;
469 case DW_CFA_offset_extended:
470 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
471 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
472 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
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;
479 case DW_CFA_restore_extended:
480 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
481 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
484 case DW_CFA_undefined:
485 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
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;
491 case DW_CFA_same_value:
492 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
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;
498 case DW_CFA_register:
499 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
500 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
501 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
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;
508 case DW_CFA_remember_state:
510 struct dwarf2_frame_state_reg_info *new_rs;
512 new_rs = XNEW (struct dwarf2_frame_state_reg_info);
514 fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs);
515 fs->regs.prev = new_rs;
519 case DW_CFA_restore_state:
521 struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;
525 complaint (&symfile_complaints, _("\
526 bad CFI data; mismatched DW_CFA_restore_state at %s"),
527 paddress (gdbarch, fs->pc));
531 xfree (fs->regs.reg);
539 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
540 fs->regs.cfa_reg = reg;
541 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
543 if (fs->armcc_cfa_offsets_sf)
544 utmp *= fs->data_align;
546 fs->regs.cfa_offset = utmp;
547 fs->regs.cfa_how = CFA_REG_OFFSET;
550 case DW_CFA_def_cfa_register:
551 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
552 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
554 fs->regs.cfa_how = CFA_REG_OFFSET;
557 case DW_CFA_def_cfa_offset:
558 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
560 if (fs->armcc_cfa_offsets_sf)
561 utmp *= fs->data_align;
563 fs->regs.cfa_offset = utmp;
564 /* cfa_how deliberately not set. */
570 case DW_CFA_def_cfa_expression:
571 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
572 fs->regs.cfa_exp_len = utmp;
573 fs->regs.cfa_exp = insn_ptr;
574 fs->regs.cfa_how = CFA_EXP;
575 insn_ptr += fs->regs.cfa_exp_len;
578 case DW_CFA_expression:
579 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
580 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
581 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
582 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
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;
589 case DW_CFA_offset_extended_sf:
590 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
591 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
592 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
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;
599 case DW_CFA_val_offset:
600 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
601 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
602 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
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;
608 case DW_CFA_val_offset_sf:
609 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
610 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
611 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
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;
617 case DW_CFA_val_expression:
618 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
619 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
620 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
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;
627 case DW_CFA_def_cfa_sf:
628 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
629 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
631 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
632 fs->regs.cfa_offset = offset * fs->data_align;
633 fs->regs.cfa_how = CFA_REG_OFFSET;
636 case DW_CFA_def_cfa_offset_sf:
637 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
638 fs->regs.cfa_offset = offset * fs->data_align;
639 /* cfa_how deliberately not set. */
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
651 int size = register_size (gdbarch, 0);
653 dwarf2_frame_state_alloc_regs (&fs->regs, 32);
654 for (reg = 8; reg < 16; reg++)
656 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
657 fs->regs.reg[reg].loc.reg = reg + 16;
659 for (reg = 16; reg < 32; reg++)
661 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
662 fs->regs.reg[reg].loc.offset = (reg - 16) * size;
667 case DW_CFA_GNU_args_size:
669 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
672 case DW_CFA_GNU_negative_offset_extended:
673 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
674 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
675 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
676 offset = utmp * 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;
683 internal_error (__FILE__, __LINE__,
684 _("Unknown CFI encountered."));
689 if (fs->initial.reg == NULL)
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;
700 /* Architecture-specific operations. */
702 /* Per-architecture data key. */
703 static struct gdbarch_data *dwarf2_frame_data;
705 struct dwarf2_frame_ops
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 *);
711 /* Check whether the THIS_FRAME is a signal trampoline. */
712 int (*signal_frame_p) (struct gdbarch *, struct frame_info *);
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);
719 /* Default architecture-specific register state initialization
723 dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
724 struct dwarf2_frame_state_reg *reg,
725 struct frame_info *this_frame)
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
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.
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,
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)."
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. */
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;
759 /* Return a default for the architecture-specific operations. */
762 dwarf2_frame_init (struct obstack *obstack)
764 struct dwarf2_frame_ops *ops;
766 ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
767 ops->init_reg = dwarf2_frame_default_init_reg;
771 /* Set the architecture-specific register state initialization
772 function for GDBARCH to INIT_REG. */
775 dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
776 void (*init_reg) (struct gdbarch *, int,
777 struct dwarf2_frame_state_reg *,
778 struct frame_info *))
780 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
782 ops->init_reg = init_reg;
785 /* Pre-initialize the register state REG for register REGNUM. */
788 dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
789 struct dwarf2_frame_state_reg *reg,
790 struct frame_info *this_frame)
792 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
794 ops->init_reg (gdbarch, regnum, reg, this_frame);
797 /* Set the architecture-specific signal trampoline recognition
798 function for GDBARCH to SIGNAL_FRAME_P. */
801 dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
802 int (*signal_frame_p) (struct gdbarch *,
803 struct frame_info *))
805 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
807 ops->signal_frame_p = signal_frame_p;
810 /* Query the architecture-specific signal frame recognizer for
814 dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
815 struct frame_info *this_frame)
817 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
819 if (ops->signal_frame_p == NULL)
821 return ops->signal_frame_p (gdbarch, this_frame);
824 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
828 dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
829 int (*adjust_regnum) (struct gdbarch *,
832 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
834 ops->adjust_regnum = adjust_regnum;
837 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
841 dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch,
842 int regnum, int eh_frame_p)
844 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
846 if (ops->adjust_regnum == NULL)
848 return ops->adjust_regnum (gdbarch, regnum, eh_frame_p);
852 dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
853 struct dwarf2_fde *fde)
855 struct compunit_symtab *cust;
857 cust = find_pc_compunit_symtab (fs->pc);
861 if (producer_is_realview (COMPUNIT_PRODUCER (cust)))
863 if (fde->cie->version == 1)
864 fs->armcc_cfa_offsets_sf = 1;
866 if (fde->cie->version == 1)
867 fs->armcc_cfa_offsets_reversed = 1;
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;
885 /* See dwarf2-frame.h. */
888 dwarf2_fetch_cfa_info (struct gdbarch *gdbarch, CORE_ADDR pc,
889 struct dwarf2_per_cu_data *data,
890 int *regnum_out, LONGEST *offset_out,
891 CORE_ADDR *text_offset_out,
892 const gdb_byte **cfa_start_out,
893 const gdb_byte **cfa_end_out)
895 struct dwarf2_fde *fde;
896 CORE_ADDR text_offset;
897 struct dwarf2_frame_state fs;
900 memset (&fs, 0, sizeof (struct dwarf2_frame_state));
904 /* Find the correct FDE. */
905 fde = dwarf2_frame_find_fde (&fs.pc, &text_offset);
907 error (_("Could not compute CFA; needed to translate this expression"));
909 /* Extract any interesting information from the CIE. */
910 fs.data_align = fde->cie->data_alignment_factor;
911 fs.code_align = fde->cie->code_alignment_factor;
912 fs.retaddr_column = fde->cie->return_address_register;
913 addr_size = fde->cie->addr_size;
915 /* Check for "quirks" - known bugs in producers. */
916 dwarf2_frame_find_quirks (&fs, fde);
918 /* First decode all the insns in the CIE. */
919 execute_cfa_program (fde, fde->cie->initial_instructions,
920 fde->cie->end, gdbarch, pc, &fs);
922 /* Save the initialized register set. */
923 fs.initial = fs.regs;
924 fs.initial.reg = dwarf2_frame_state_copy_regs (&fs.regs);
926 /* Then decode the insns in the FDE up to our target PC. */
927 execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs);
929 /* Calculate the CFA. */
930 switch (fs.regs.cfa_how)
934 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, fs.regs.cfa_reg);
937 error (_("Unable to access DWARF register number %d"),
938 (int) fs.regs.cfa_reg); /* FIXME */
940 *regnum_out = regnum;
941 if (fs.armcc_cfa_offsets_reversed)
942 *offset_out = -fs.regs.cfa_offset;
944 *offset_out = fs.regs.cfa_offset;
949 *text_offset_out = text_offset;
950 *cfa_start_out = fs.regs.cfa_exp;
951 *cfa_end_out = fs.regs.cfa_exp + fs.regs.cfa_exp_len;
955 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
960 struct dwarf2_frame_cache
962 /* DWARF Call Frame Address. */
965 /* Set if the return address column was marked as unavailable
966 (required non-collected memory or registers to compute). */
967 int unavailable_retaddr;
969 /* Set if the return address column was marked as undefined. */
970 int undefined_retaddr;
972 /* Saved registers, indexed by GDB register number, not by DWARF
974 struct dwarf2_frame_state_reg *reg;
976 /* Return address register. */
977 struct dwarf2_frame_state_reg retaddr_reg;
979 /* Target address size in bytes. */
982 /* The .text offset. */
983 CORE_ADDR text_offset;
985 /* True if we already checked whether this frame is the bottom frame
986 of a virtual tail call frame chain. */
987 int checked_tailcall_bottom;
989 /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME
990 sequence. If NULL then it is a normal case with no TAILCALL_FRAME
991 involved. Non-bottom frames of a virtual tail call frames chain use
992 dwarf2_tailcall_frame_unwind unwinder so this field does not apply for
994 void *tailcall_cache;
996 /* The number of bytes to subtract from TAILCALL_FRAME frames frame
997 base to get the SP, to simulate the return address pushed on the
999 LONGEST entry_cfa_sp_offset;
1000 int entry_cfa_sp_offset_p;
1003 /* A cleanup that sets a pointer to NULL. */
1006 clear_pointer_cleanup (void *arg)
1013 static struct dwarf2_frame_cache *
1014 dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
1016 struct cleanup *reset_cache_cleanup, *old_chain;
1017 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1018 const int num_regs = gdbarch_num_regs (gdbarch)
1019 + gdbarch_num_pseudo_regs (gdbarch);
1020 struct dwarf2_frame_cache *cache;
1021 struct dwarf2_frame_state *fs;
1022 struct dwarf2_fde *fde;
1023 volatile struct gdb_exception ex;
1025 const gdb_byte *instr;
1030 /* Allocate a new cache. */
1031 cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
1032 cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
1033 *this_cache = cache;
1034 reset_cache_cleanup = make_cleanup (clear_pointer_cleanup, this_cache);
1036 /* Allocate and initialize the frame state. */
1037 fs = XCNEW (struct dwarf2_frame_state);
1038 old_chain = make_cleanup (dwarf2_frame_state_free, fs);
1042 Note that if the next frame is never supposed to return (i.e. a call
1043 to abort), the compiler might optimize away the instruction at
1044 its return address. As a result the return address will
1045 point at some random instruction, and the CFI for that
1046 instruction is probably worthless to us. GCC's unwinder solves
1047 this problem by substracting 1 from the return address to get an
1048 address in the middle of a presumed call instruction (or the
1049 instruction in the associated delay slot). This should only be
1050 done for "normal" frames and not for resume-type frames (signal
1051 handlers, sentinel frames, dummy frames). The function
1052 get_frame_address_in_block does just this. It's not clear how
1053 reliable the method is though; there is the potential for the
1054 register state pre-call being different to that on return. */
1055 fs->pc = get_frame_address_in_block (this_frame);
1057 /* Find the correct FDE. */
1058 fde = dwarf2_frame_find_fde (&fs->pc, &cache->text_offset);
1059 gdb_assert (fde != NULL);
1061 /* Extract any interesting information from the CIE. */
1062 fs->data_align = fde->cie->data_alignment_factor;
1063 fs->code_align = fde->cie->code_alignment_factor;
1064 fs->retaddr_column = fde->cie->return_address_register;
1065 cache->addr_size = fde->cie->addr_size;
1067 /* Check for "quirks" - known bugs in producers. */
1068 dwarf2_frame_find_quirks (fs, fde);
1070 /* First decode all the insns in the CIE. */
1071 execute_cfa_program (fde, fde->cie->initial_instructions,
1072 fde->cie->end, gdbarch,
1073 get_frame_address_in_block (this_frame), fs);
1075 /* Save the initialized register set. */
1076 fs->initial = fs->regs;
1077 fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs);
1079 if (get_frame_func_if_available (this_frame, &entry_pc))
1081 /* Decode the insns in the FDE up to the entry PC. */
1082 instr = execute_cfa_program (fde, fde->instructions, fde->end, gdbarch,
1085 if (fs->regs.cfa_how == CFA_REG_OFFSET
1086 && (gdbarch_dwarf2_reg_to_regnum (gdbarch, fs->regs.cfa_reg)
1087 == gdbarch_sp_regnum (gdbarch)))
1089 cache->entry_cfa_sp_offset = fs->regs.cfa_offset;
1090 cache->entry_cfa_sp_offset_p = 1;
1094 instr = fde->instructions;
1096 /* Then decode the insns in the FDE up to our target PC. */
1097 execute_cfa_program (fde, instr, fde->end, gdbarch,
1098 get_frame_address_in_block (this_frame), fs);
1100 TRY_CATCH (ex, RETURN_MASK_ERROR)
1102 /* Calculate the CFA. */
1103 switch (fs->regs.cfa_how)
1105 case CFA_REG_OFFSET:
1106 cache->cfa = read_addr_from_reg (this_frame, fs->regs.cfa_reg);
1107 if (fs->armcc_cfa_offsets_reversed)
1108 cache->cfa -= fs->regs.cfa_offset;
1110 cache->cfa += fs->regs.cfa_offset;
1115 execute_stack_op (fs->regs.cfa_exp, fs->regs.cfa_exp_len,
1116 cache->addr_size, cache->text_offset,
1121 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
1126 if (ex.error == NOT_AVAILABLE_ERROR)
1128 cache->unavailable_retaddr = 1;
1129 do_cleanups (old_chain);
1130 discard_cleanups (reset_cache_cleanup);
1134 throw_exception (ex);
1137 /* Initialize the register state. */
1141 for (regnum = 0; regnum < num_regs; regnum++)
1142 dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame);
1145 /* Go through the DWARF2 CFI generated table and save its register
1146 location information in the cache. Note that we don't skip the
1147 return address column; it's perfectly all right for it to
1148 correspond to a real register. If it doesn't correspond to a
1149 real register, or if we shouldn't treat it as such,
1150 gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside
1151 the range [0, gdbarch_num_regs). */
1153 int column; /* CFI speak for "register number". */
1155 for (column = 0; column < fs->regs.num_regs; column++)
1157 /* Use the GDB register number as the destination index. */
1158 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, column);
1160 /* If there's no corresponding GDB register, ignore it. */
1161 if (regnum < 0 || regnum >= num_regs)
1164 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1165 of all debug info registers. If it doesn't, complain (but
1166 not too loudly). It turns out that GCC assumes that an
1167 unspecified register implies "same value" when CFI (draft
1168 7) specifies nothing at all. Such a register could equally
1169 be interpreted as "undefined". Also note that this check
1170 isn't sufficient; it only checks that all registers in the
1171 range [0 .. max column] are specified, and won't detect
1172 problems when a debug info register falls outside of the
1173 table. We need a way of iterating through all the valid
1174 DWARF2 register numbers. */
1175 if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
1177 if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED)
1178 complaint (&symfile_complaints, _("\
1179 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1180 gdbarch_register_name (gdbarch, regnum),
1181 paddress (gdbarch, fs->pc));
1184 cache->reg[regnum] = fs->regs.reg[column];
1188 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1189 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1193 for (regnum = 0; regnum < num_regs; regnum++)
1195 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
1196 || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
1198 struct dwarf2_frame_state_reg *retaddr_reg =
1199 &fs->regs.reg[fs->retaddr_column];
1201 /* It seems rather bizarre to specify an "empty" column as
1202 the return adress column. However, this is exactly
1203 what GCC does on some targets. It turns out that GCC
1204 assumes that the return address can be found in the
1205 register corresponding to the return address column.
1206 Incidentally, that's how we should treat a return
1207 address column specifying "same value" too. */
1208 if (fs->retaddr_column < fs->regs.num_regs
1209 && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
1210 && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
1212 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1213 cache->reg[regnum] = *retaddr_reg;
1215 cache->retaddr_reg = *retaddr_reg;
1219 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1221 cache->reg[regnum].loc.reg = fs->retaddr_column;
1222 cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
1226 cache->retaddr_reg.loc.reg = fs->retaddr_column;
1227 cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG;
1234 if (fs->retaddr_column < fs->regs.num_regs
1235 && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
1236 cache->undefined_retaddr = 1;
1238 do_cleanups (old_chain);
1239 discard_cleanups (reset_cache_cleanup);
1243 static enum unwind_stop_reason
1244 dwarf2_frame_unwind_stop_reason (struct frame_info *this_frame,
1247 struct dwarf2_frame_cache *cache
1248 = dwarf2_frame_cache (this_frame, this_cache);
1250 if (cache->unavailable_retaddr)
1251 return UNWIND_UNAVAILABLE;
1253 if (cache->undefined_retaddr)
1254 return UNWIND_OUTERMOST;
1256 return UNWIND_NO_REASON;
1260 dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
1261 struct frame_id *this_id)
1263 struct dwarf2_frame_cache *cache =
1264 dwarf2_frame_cache (this_frame, this_cache);
1266 if (cache->unavailable_retaddr)
1267 (*this_id) = frame_id_build_unavailable_stack (get_frame_func (this_frame));
1268 else if (cache->undefined_retaddr)
1271 (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
1274 static struct value *
1275 dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache,
1278 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1279 struct dwarf2_frame_cache *cache =
1280 dwarf2_frame_cache (this_frame, this_cache);
1284 /* Check whether THIS_FRAME is the bottom frame of a virtual tail
1285 call frame chain. */
1286 if (!cache->checked_tailcall_bottom)
1288 cache->checked_tailcall_bottom = 1;
1289 dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache,
1290 (cache->entry_cfa_sp_offset_p
1291 ? &cache->entry_cfa_sp_offset : NULL));
1294 /* Non-bottom frames of a virtual tail call frames chain use
1295 dwarf2_tailcall_frame_unwind unwinder so this code does not apply for
1296 them. If dwarf2_tailcall_prev_register_first does not have specific value
1297 unwind the register, tail call frames are assumed to have the register set
1298 of the top caller. */
1299 if (cache->tailcall_cache)
1303 val = dwarf2_tailcall_prev_register_first (this_frame,
1304 &cache->tailcall_cache,
1310 switch (cache->reg[regnum].how)
1312 case DWARF2_FRAME_REG_UNDEFINED:
1313 /* If CFI explicitly specified that the value isn't defined,
1314 mark it as optimized away; the value isn't available. */
1315 return frame_unwind_got_optimized (this_frame, regnum);
1317 case DWARF2_FRAME_REG_SAVED_OFFSET:
1318 addr = cache->cfa + cache->reg[regnum].loc.offset;
1319 return frame_unwind_got_memory (this_frame, regnum, addr);
1321 case DWARF2_FRAME_REG_SAVED_REG:
1323 = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg);
1324 return frame_unwind_got_register (this_frame, regnum, realnum);
1326 case DWARF2_FRAME_REG_SAVED_EXP:
1327 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1328 cache->reg[regnum].exp_len,
1329 cache->addr_size, cache->text_offset,
1330 this_frame, cache->cfa, 1);
1331 return frame_unwind_got_memory (this_frame, regnum, addr);
1333 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET:
1334 addr = cache->cfa + cache->reg[regnum].loc.offset;
1335 return frame_unwind_got_constant (this_frame, regnum, addr);
1337 case DWARF2_FRAME_REG_SAVED_VAL_EXP:
1338 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1339 cache->reg[regnum].exp_len,
1340 cache->addr_size, cache->text_offset,
1341 this_frame, cache->cfa, 1);
1342 return frame_unwind_got_constant (this_frame, regnum, addr);
1344 case DWARF2_FRAME_REG_UNSPECIFIED:
1345 /* GCC, in its infinite wisdom decided to not provide unwind
1346 information for registers that are "same value". Since
1347 DWARF2 (3 draft 7) doesn't define such behavior, said
1348 registers are actually undefined (which is different to CFI
1349 "undefined"). Code above issues a complaint about this.
1350 Here just fudge the books, assume GCC, and that the value is
1351 more inner on the stack. */
1352 return frame_unwind_got_register (this_frame, regnum, regnum);
1354 case DWARF2_FRAME_REG_SAME_VALUE:
1355 return frame_unwind_got_register (this_frame, regnum, regnum);
1357 case DWARF2_FRAME_REG_CFA:
1358 return frame_unwind_got_address (this_frame, regnum, cache->cfa);
1360 case DWARF2_FRAME_REG_CFA_OFFSET:
1361 addr = cache->cfa + cache->reg[regnum].loc.offset;
1362 return frame_unwind_got_address (this_frame, regnum, addr);
1364 case DWARF2_FRAME_REG_RA_OFFSET:
1365 addr = cache->reg[regnum].loc.offset;
1366 regnum = gdbarch_dwarf2_reg_to_regnum
1367 (gdbarch, cache->retaddr_reg.loc.reg);
1368 addr += get_frame_register_unsigned (this_frame, regnum);
1369 return frame_unwind_got_address (this_frame, regnum, addr);
1371 case DWARF2_FRAME_REG_FN:
1372 return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum);
1375 internal_error (__FILE__, __LINE__, _("Unknown register rule."));
1379 /* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail
1380 call frames chain. */
1383 dwarf2_frame_dealloc_cache (struct frame_info *self, void *this_cache)
1385 struct dwarf2_frame_cache *cache = dwarf2_frame_cache (self, &this_cache);
1387 if (cache->tailcall_cache)
1388 dwarf2_tailcall_frame_unwind.dealloc_cache (self, cache->tailcall_cache);
1392 dwarf2_frame_sniffer (const struct frame_unwind *self,
1393 struct frame_info *this_frame, void **this_cache)
1395 /* Grab an address that is guarenteed to reside somewhere within the
1396 function. get_frame_pc(), with a no-return next function, can
1397 end up returning something past the end of this function's body.
1398 If the frame we're sniffing for is a signal frame whose start
1399 address is placed on the stack by the OS, its FDE must
1400 extend one byte before its start address or we could potentially
1401 select the FDE of the previous function. */
1402 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1403 struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr, NULL);
1408 /* On some targets, signal trampolines may have unwind information.
1409 We need to recognize them so that we set the frame type
1412 if (fde->cie->signal_frame
1413 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame),
1415 return self->type == SIGTRAMP_FRAME;
1417 if (self->type != NORMAL_FRAME)
1423 static const struct frame_unwind dwarf2_frame_unwind =
1426 dwarf2_frame_unwind_stop_reason,
1427 dwarf2_frame_this_id,
1428 dwarf2_frame_prev_register,
1430 dwarf2_frame_sniffer,
1431 dwarf2_frame_dealloc_cache
1434 static const struct frame_unwind dwarf2_signal_frame_unwind =
1437 dwarf2_frame_unwind_stop_reason,
1438 dwarf2_frame_this_id,
1439 dwarf2_frame_prev_register,
1441 dwarf2_frame_sniffer,
1443 /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */
1447 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1450 dwarf2_append_unwinders (struct gdbarch *gdbarch)
1452 /* TAILCALL_FRAME must be first to find the record by
1453 dwarf2_tailcall_sniffer_first. */
1454 frame_unwind_append_unwinder (gdbarch, &dwarf2_tailcall_frame_unwind);
1456 frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind);
1457 frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind);
1461 /* There is no explicitly defined relationship between the CFA and the
1462 location of frame's local variables and arguments/parameters.
1463 Therefore, frame base methods on this page should probably only be
1464 used as a last resort, just to avoid printing total garbage as a
1465 response to the "info frame" command. */
1468 dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache)
1470 struct dwarf2_frame_cache *cache =
1471 dwarf2_frame_cache (this_frame, this_cache);
1476 static const struct frame_base dwarf2_frame_base =
1478 &dwarf2_frame_unwind,
1479 dwarf2_frame_base_address,
1480 dwarf2_frame_base_address,
1481 dwarf2_frame_base_address
1484 const struct frame_base *
1485 dwarf2_frame_base_sniffer (struct frame_info *this_frame)
1487 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1489 if (dwarf2_frame_find_fde (&block_addr, NULL))
1490 return &dwarf2_frame_base;
1495 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1496 the DWARF unwinder. This is used to implement
1497 DW_OP_call_frame_cfa. */
1500 dwarf2_frame_cfa (struct frame_info *this_frame)
1502 if (frame_unwinder_is (this_frame, &record_btrace_tailcall_frame_unwind)
1503 || frame_unwinder_is (this_frame, &record_btrace_frame_unwind))
1504 throw_error (NOT_AVAILABLE_ERROR,
1505 _("cfa not available for record btrace target"));
1507 while (get_frame_type (this_frame) == INLINE_FRAME)
1508 this_frame = get_prev_frame (this_frame);
1509 if (get_frame_unwind_stop_reason (this_frame) == UNWIND_UNAVAILABLE)
1510 throw_error (NOT_AVAILABLE_ERROR,
1511 _("can't compute CFA for this frame: "
1512 "required registers or memory are unavailable"));
1514 if (get_frame_id (this_frame).stack_status != FID_STACK_VALID)
1515 throw_error (NOT_AVAILABLE_ERROR,
1516 _("can't compute CFA for this frame: "
1517 "frame base not available"));
1519 return get_frame_base (this_frame);
1522 const struct objfile_data *dwarf2_frame_objfile_data;
1525 read_1_byte (bfd *abfd, const gdb_byte *buf)
1527 return bfd_get_8 (abfd, buf);
1531 read_4_bytes (bfd *abfd, const gdb_byte *buf)
1533 return bfd_get_32 (abfd, buf);
1537 read_8_bytes (bfd *abfd, const gdb_byte *buf)
1539 return bfd_get_64 (abfd, buf);
1543 read_initial_length (bfd *abfd, const gdb_byte *buf,
1544 unsigned int *bytes_read_ptr)
1548 result = bfd_get_32 (abfd, buf);
1549 if (result == 0xffffffff)
1551 result = bfd_get_64 (abfd, buf + 4);
1552 *bytes_read_ptr = 12;
1555 *bytes_read_ptr = 4;
1561 /* Pointer encoding helper functions. */
1563 /* GCC supports exception handling based on DWARF2 CFI. However, for
1564 technical reasons, it encodes addresses in its FDE's in a different
1565 way. Several "pointer encodings" are supported. The encoding
1566 that's used for a particular FDE is determined by the 'R'
1567 augmentation in the associated CIE. The argument of this
1568 augmentation is a single byte.
1570 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1571 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1572 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1573 address should be interpreted (absolute, relative to the current
1574 position in the FDE, ...). Bit 7, indicates that the address
1575 should be dereferenced. */
1578 encoding_for_size (unsigned int size)
1583 return DW_EH_PE_udata2;
1585 return DW_EH_PE_udata4;
1587 return DW_EH_PE_udata8;
1589 internal_error (__FILE__, __LINE__, _("Unsupported address size"));
1594 read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
1595 int ptr_len, const gdb_byte *buf,
1596 unsigned int *bytes_read_ptr,
1597 CORE_ADDR func_base)
1602 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1604 if (encoding & DW_EH_PE_indirect)
1605 internal_error (__FILE__, __LINE__,
1606 _("Unsupported encoding: DW_EH_PE_indirect"));
1608 *bytes_read_ptr = 0;
1610 switch (encoding & 0x70)
1612 case DW_EH_PE_absptr:
1615 case DW_EH_PE_pcrel:
1616 base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section);
1617 base += (buf - unit->dwarf_frame_buffer);
1619 case DW_EH_PE_datarel:
1622 case DW_EH_PE_textrel:
1625 case DW_EH_PE_funcrel:
1628 case DW_EH_PE_aligned:
1630 offset = buf - unit->dwarf_frame_buffer;
1631 if ((offset % ptr_len) != 0)
1633 *bytes_read_ptr = ptr_len - (offset % ptr_len);
1634 buf += *bytes_read_ptr;
1638 internal_error (__FILE__, __LINE__,
1639 _("Invalid or unsupported encoding"));
1642 if ((encoding & 0x07) == 0x00)
1644 encoding |= encoding_for_size (ptr_len);
1645 if (bfd_get_sign_extend_vma (unit->abfd))
1646 encoding |= DW_EH_PE_signed;
1649 switch (encoding & 0x0f)
1651 case DW_EH_PE_uleb128:
1654 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1656 *bytes_read_ptr += safe_read_uleb128 (buf, end_buf, &value) - buf;
1657 return base + value;
1659 case DW_EH_PE_udata2:
1660 *bytes_read_ptr += 2;
1661 return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf));
1662 case DW_EH_PE_udata4:
1663 *bytes_read_ptr += 4;
1664 return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf));
1665 case DW_EH_PE_udata8:
1666 *bytes_read_ptr += 8;
1667 return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf));
1668 case DW_EH_PE_sleb128:
1671 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1673 *bytes_read_ptr += safe_read_sleb128 (buf, end_buf, &value) - buf;
1674 return base + value;
1676 case DW_EH_PE_sdata2:
1677 *bytes_read_ptr += 2;
1678 return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf));
1679 case DW_EH_PE_sdata4:
1680 *bytes_read_ptr += 4;
1681 return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf));
1682 case DW_EH_PE_sdata8:
1683 *bytes_read_ptr += 8;
1684 return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf));
1686 internal_error (__FILE__, __LINE__,
1687 _("Invalid or unsupported encoding"));
1693 bsearch_cie_cmp (const void *key, const void *element)
1695 ULONGEST cie_pointer = *(ULONGEST *) key;
1696 struct dwarf2_cie *cie = *(struct dwarf2_cie **) element;
1698 if (cie_pointer == cie->cie_pointer)
1701 return (cie_pointer < cie->cie_pointer) ? -1 : 1;
1704 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1705 static struct dwarf2_cie *
1706 find_cie (struct dwarf2_cie_table *cie_table, ULONGEST cie_pointer)
1708 struct dwarf2_cie **p_cie;
1710 /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
1711 bsearch be non-NULL. */
1712 if (cie_table->entries == NULL)
1714 gdb_assert (cie_table->num_entries == 0);
1718 p_cie = bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries,
1719 sizeof (cie_table->entries[0]), bsearch_cie_cmp);
1725 /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1727 add_cie (struct dwarf2_cie_table *cie_table, struct dwarf2_cie *cie)
1729 const int n = cie_table->num_entries;
1732 || cie_table->entries[n - 1]->cie_pointer < cie->cie_pointer);
1734 cie_table->entries =
1735 xrealloc (cie_table->entries, (n + 1) * sizeof (cie_table->entries[0]));
1736 cie_table->entries[n] = cie;
1737 cie_table->num_entries = n + 1;
1741 bsearch_fde_cmp (const void *key, const void *element)
1743 CORE_ADDR seek_pc = *(CORE_ADDR *) key;
1744 struct dwarf2_fde *fde = *(struct dwarf2_fde **) element;
1746 if (seek_pc < fde->initial_location)
1748 if (seek_pc < fde->initial_location + fde->address_range)
1753 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1754 inital location associated with it into *PC. */
1756 static struct dwarf2_fde *
1757 dwarf2_frame_find_fde (CORE_ADDR *pc, CORE_ADDR *out_offset)
1759 struct objfile *objfile;
1761 ALL_OBJFILES (objfile)
1763 struct dwarf2_fde_table *fde_table;
1764 struct dwarf2_fde **p_fde;
1768 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1769 if (fde_table == NULL)
1771 dwarf2_build_frame_info (objfile);
1772 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1774 gdb_assert (fde_table != NULL);
1776 if (fde_table->num_entries == 0)
1779 gdb_assert (objfile->section_offsets);
1780 offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
1782 gdb_assert (fde_table->num_entries > 0);
1783 if (*pc < offset + fde_table->entries[0]->initial_location)
1786 seek_pc = *pc - offset;
1787 p_fde = bsearch (&seek_pc, fde_table->entries, fde_table->num_entries,
1788 sizeof (fde_table->entries[0]), bsearch_fde_cmp);
1791 *pc = (*p_fde)->initial_location + offset;
1793 *out_offset = offset;
1800 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1802 add_fde (struct dwarf2_fde_table *fde_table, struct dwarf2_fde *fde)
1804 if (fde->address_range == 0)
1805 /* Discard useless FDEs. */
1808 fde_table->num_entries += 1;
1809 fde_table->entries =
1810 xrealloc (fde_table->entries,
1811 fde_table->num_entries * sizeof (fde_table->entries[0]));
1812 fde_table->entries[fde_table->num_entries - 1] = fde;
1815 #define DW64_CIE_ID 0xffffffffffffffffULL
1817 /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
1822 EH_CIE_TYPE_ID = 1 << 0,
1823 EH_FDE_TYPE_ID = 1 << 1,
1824 EH_CIE_OR_FDE_TYPE_ID = EH_CIE_TYPE_ID | EH_FDE_TYPE_ID
1827 static const gdb_byte *decode_frame_entry (struct comp_unit *unit,
1828 const gdb_byte *start,
1830 struct dwarf2_cie_table *cie_table,
1831 struct dwarf2_fde_table *fde_table,
1832 enum eh_frame_type entry_type);
1834 /* Decode the next CIE or FDE, entry_type specifies the expected type.
1835 Return NULL if invalid input, otherwise the next byte to be processed. */
1837 static const gdb_byte *
1838 decode_frame_entry_1 (struct comp_unit *unit, const gdb_byte *start,
1840 struct dwarf2_cie_table *cie_table,
1841 struct dwarf2_fde_table *fde_table,
1842 enum eh_frame_type entry_type)
1844 struct gdbarch *gdbarch = get_objfile_arch (unit->objfile);
1845 const gdb_byte *buf, *end;
1847 unsigned int bytes_read;
1850 ULONGEST cie_pointer;
1855 length = read_initial_length (unit->abfd, buf, &bytes_read);
1859 /* Are we still within the section? */
1860 if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
1866 /* Distinguish between 32 and 64-bit encoded frame info. */
1867 dwarf64_p = (bytes_read == 12);
1869 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1873 cie_id = DW64_CIE_ID;
1879 cie_pointer = read_8_bytes (unit->abfd, buf);
1884 cie_pointer = read_4_bytes (unit->abfd, buf);
1888 if (cie_pointer == cie_id)
1890 /* This is a CIE. */
1891 struct dwarf2_cie *cie;
1893 unsigned int cie_version;
1895 /* Check that a CIE was expected. */
1896 if ((entry_type & EH_CIE_TYPE_ID) == 0)
1897 error (_("Found a CIE when not expecting it."));
1899 /* Record the offset into the .debug_frame section of this CIE. */
1900 cie_pointer = start - unit->dwarf_frame_buffer;
1902 /* Check whether we've already read it. */
1903 if (find_cie (cie_table, cie_pointer))
1906 cie = (struct dwarf2_cie *)
1907 obstack_alloc (&unit->objfile->objfile_obstack,
1908 sizeof (struct dwarf2_cie));
1909 cie->initial_instructions = NULL;
1910 cie->cie_pointer = cie_pointer;
1912 /* The encoding for FDE's in a normal .debug_frame section
1913 depends on the target address size. */
1914 cie->encoding = DW_EH_PE_absptr;
1916 /* We'll determine the final value later, but we need to
1917 initialize it conservatively. */
1918 cie->signal_frame = 0;
1920 /* Check version number. */
1921 cie_version = read_1_byte (unit->abfd, buf);
1922 if (cie_version != 1 && cie_version != 3 && cie_version != 4)
1924 cie->version = cie_version;
1927 /* Interpret the interesting bits of the augmentation. */
1928 cie->augmentation = augmentation = (char *) buf;
1929 buf += (strlen (augmentation) + 1);
1931 /* Ignore armcc augmentations. We only use them for quirks,
1932 and that doesn't happen until later. */
1933 if (strncmp (augmentation, "armcc", 5) == 0)
1934 augmentation += strlen (augmentation);
1936 /* The GCC 2.x "eh" augmentation has a pointer immediately
1937 following the augmentation string, so it must be handled
1939 if (augmentation[0] == 'e' && augmentation[1] == 'h')
1942 buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1946 if (cie->version >= 4)
1948 /* FIXME: check that this is the same as from the CU header. */
1949 cie->addr_size = read_1_byte (unit->abfd, buf);
1951 cie->segment_size = read_1_byte (unit->abfd, buf);
1956 cie->addr_size = gdbarch_dwarf2_addr_size (gdbarch);
1957 cie->segment_size = 0;
1959 /* Address values in .eh_frame sections are defined to have the
1960 target's pointer size. Watchout: This breaks frame info for
1961 targets with pointer size < address size, unless a .debug_frame
1962 section exists as well. */
1964 cie->ptr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1966 cie->ptr_size = cie->addr_size;
1968 buf = gdb_read_uleb128 (buf, end, &uleb128);
1971 cie->code_alignment_factor = uleb128;
1973 buf = gdb_read_sleb128 (buf, end, &sleb128);
1976 cie->data_alignment_factor = sleb128;
1978 if (cie_version == 1)
1980 cie->return_address_register = read_1_byte (unit->abfd, buf);
1985 buf = gdb_read_uleb128 (buf, end, &uleb128);
1988 cie->return_address_register = uleb128;
1991 cie->return_address_register
1992 = dwarf2_frame_adjust_regnum (gdbarch,
1993 cie->return_address_register,
1996 cie->saw_z_augmentation = (*augmentation == 'z');
1997 if (cie->saw_z_augmentation)
2001 buf = gdb_read_uleb128 (buf, end, &length);
2004 cie->initial_instructions = buf + length;
2008 while (*augmentation)
2010 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
2011 if (*augmentation == 'L')
2018 /* "R" indicates a byte indicating how FDE addresses are encoded. */
2019 else if (*augmentation == 'R')
2021 cie->encoding = *buf++;
2025 /* "P" indicates a personality routine in the CIE augmentation. */
2026 else if (*augmentation == 'P')
2028 /* Skip. Avoid indirection since we throw away the result. */
2029 gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect;
2030 read_encoded_value (unit, encoding, cie->ptr_size,
2031 buf, &bytes_read, 0);
2036 /* "S" indicates a signal frame, such that the return
2037 address must not be decremented to locate the call frame
2038 info for the previous frame; it might even be the first
2039 instruction of a function, so decrementing it would take
2040 us to a different function. */
2041 else if (*augmentation == 'S')
2043 cie->signal_frame = 1;
2047 /* Otherwise we have an unknown augmentation. Assume that either
2048 there is no augmentation data, or we saw a 'z' prefix. */
2051 if (cie->initial_instructions)
2052 buf = cie->initial_instructions;
2057 cie->initial_instructions = buf;
2061 add_cie (cie_table, cie);
2065 /* This is a FDE. */
2066 struct dwarf2_fde *fde;
2069 /* Check that an FDE was expected. */
2070 if ((entry_type & EH_FDE_TYPE_ID) == 0)
2071 error (_("Found an FDE when not expecting it."));
2073 /* In an .eh_frame section, the CIE pointer is the delta between the
2074 address within the FDE where the CIE pointer is stored and the
2075 address of the CIE. Convert it to an offset into the .eh_frame
2079 cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
2080 cie_pointer -= (dwarf64_p ? 8 : 4);
2083 /* In either case, validate the result is still within the section. */
2084 if (cie_pointer >= unit->dwarf_frame_size)
2087 fde = (struct dwarf2_fde *)
2088 obstack_alloc (&unit->objfile->objfile_obstack,
2089 sizeof (struct dwarf2_fde));
2090 fde->cie = find_cie (cie_table, cie_pointer);
2091 if (fde->cie == NULL)
2093 decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer,
2094 eh_frame_p, cie_table, fde_table,
2096 fde->cie = find_cie (cie_table, cie_pointer);
2099 gdb_assert (fde->cie != NULL);
2101 addr = read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size,
2102 buf, &bytes_read, 0);
2103 fde->initial_location = gdbarch_adjust_dwarf2_addr (gdbarch, addr);
2106 fde->address_range =
2107 read_encoded_value (unit, fde->cie->encoding & 0x0f,
2108 fde->cie->ptr_size, buf, &bytes_read, 0);
2109 addr = gdbarch_adjust_dwarf2_addr (gdbarch, addr + fde->address_range);
2110 fde->address_range = addr - fde->initial_location;
2113 /* A 'z' augmentation in the CIE implies the presence of an
2114 augmentation field in the FDE as well. The only thing known
2115 to be in here at present is the LSDA entry for EH. So we
2116 can skip the whole thing. */
2117 if (fde->cie->saw_z_augmentation)
2121 buf = gdb_read_uleb128 (buf, end, &length);
2129 fde->instructions = buf;
2132 fde->eh_frame_p = eh_frame_p;
2134 add_fde (fde_table, fde);
2140 /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
2141 expect an FDE or a CIE. */
2143 static const gdb_byte *
2144 decode_frame_entry (struct comp_unit *unit, const gdb_byte *start,
2146 struct dwarf2_cie_table *cie_table,
2147 struct dwarf2_fde_table *fde_table,
2148 enum eh_frame_type entry_type)
2150 enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
2151 const gdb_byte *ret;
2152 ptrdiff_t start_offset;
2156 ret = decode_frame_entry_1 (unit, start, eh_frame_p,
2157 cie_table, fde_table, entry_type);
2161 /* We have corrupt input data of some form. */
2163 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
2164 and mismatches wrt padding and alignment of debug sections. */
2165 /* Note that there is no requirement in the standard for any
2166 alignment at all in the frame unwind sections. Testing for
2167 alignment before trying to interpret data would be incorrect.
2169 However, GCC traditionally arranged for frame sections to be
2170 sized such that the FDE length and CIE fields happen to be
2171 aligned (in theory, for performance). This, unfortunately,
2172 was done with .align directives, which had the side effect of
2173 forcing the section to be aligned by the linker.
2175 This becomes a problem when you have some other producer that
2176 creates frame sections that are not as strictly aligned. That
2177 produces a hole in the frame info that gets filled by the
2180 The GCC behaviour is arguably a bug, but it's effectively now
2181 part of the ABI, so we're now stuck with it, at least at the
2182 object file level. A smart linker may decide, in the process
2183 of compressing duplicate CIE information, that it can rewrite
2184 the entire output section without this extra padding. */
2186 start_offset = start - unit->dwarf_frame_buffer;
2187 if (workaround < ALIGN4 && (start_offset & 3) != 0)
2189 start += 4 - (start_offset & 3);
2190 workaround = ALIGN4;
2193 if (workaround < ALIGN8 && (start_offset & 7) != 0)
2195 start += 8 - (start_offset & 7);
2196 workaround = ALIGN8;
2200 /* Nothing left to try. Arrange to return as if we've consumed
2201 the entire input section. Hopefully we'll get valid info from
2202 the other of .debug_frame/.eh_frame. */
2204 ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
2214 complaint (&symfile_complaints, _("\
2215 Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
2216 unit->dwarf_frame_section->owner->filename,
2217 unit->dwarf_frame_section->name);
2221 complaint (&symfile_complaints, _("\
2222 Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
2223 unit->dwarf_frame_section->owner->filename,
2224 unit->dwarf_frame_section->name);
2228 complaint (&symfile_complaints,
2229 _("Corrupt data in %s:%s"),
2230 unit->dwarf_frame_section->owner->filename,
2231 unit->dwarf_frame_section->name);
2239 qsort_fde_cmp (const void *a, const void *b)
2241 struct dwarf2_fde *aa = *(struct dwarf2_fde **)a;
2242 struct dwarf2_fde *bb = *(struct dwarf2_fde **)b;
2244 if (aa->initial_location == bb->initial_location)
2246 if (aa->address_range != bb->address_range
2247 && aa->eh_frame_p == 0 && bb->eh_frame_p == 0)
2248 /* Linker bug, e.g. gold/10400.
2249 Work around it by keeping stable sort order. */
2250 return (a < b) ? -1 : 1;
2252 /* Put eh_frame entries after debug_frame ones. */
2253 return aa->eh_frame_p - bb->eh_frame_p;
2256 return (aa->initial_location < bb->initial_location) ? -1 : 1;
2260 dwarf2_build_frame_info (struct objfile *objfile)
2262 struct comp_unit *unit;
2263 const gdb_byte *frame_ptr;
2264 struct dwarf2_cie_table cie_table;
2265 struct dwarf2_fde_table fde_table;
2266 struct dwarf2_fde_table *fde_table2;
2267 volatile struct gdb_exception e;
2269 cie_table.num_entries = 0;
2270 cie_table.entries = NULL;
2272 fde_table.num_entries = 0;
2273 fde_table.entries = NULL;
2275 /* Build a minimal decoding of the DWARF2 compilation unit. */
2276 unit = (struct comp_unit *) obstack_alloc (&objfile->objfile_obstack,
2277 sizeof (struct comp_unit));
2278 unit->abfd = objfile->obfd;
2279 unit->objfile = objfile;
2283 if (objfile->separate_debug_objfile_backlink == NULL)
2285 /* Do not read .eh_frame from separate file as they must be also
2286 present in the main file. */
2287 dwarf2_get_section_info (objfile, DWARF2_EH_FRAME,
2288 &unit->dwarf_frame_section,
2289 &unit->dwarf_frame_buffer,
2290 &unit->dwarf_frame_size);
2291 if (unit->dwarf_frame_size)
2293 asection *got, *txt;
2295 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2296 that is used for the i386/amd64 target, which currently is
2297 the only target in GCC that supports/uses the
2298 DW_EH_PE_datarel encoding. */
2299 got = bfd_get_section_by_name (unit->abfd, ".got");
2301 unit->dbase = got->vma;
2303 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2305 txt = bfd_get_section_by_name (unit->abfd, ".text");
2307 unit->tbase = txt->vma;
2309 TRY_CATCH (e, RETURN_MASK_ERROR)
2311 frame_ptr = unit->dwarf_frame_buffer;
2312 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2313 frame_ptr = decode_frame_entry (unit, frame_ptr, 1,
2314 &cie_table, &fde_table,
2315 EH_CIE_OR_FDE_TYPE_ID);
2320 warning (_("skipping .eh_frame info of %s: %s"),
2321 objfile_name (objfile), e.message);
2323 if (fde_table.num_entries != 0)
2325 xfree (fde_table.entries);
2326 fde_table.entries = NULL;
2327 fde_table.num_entries = 0;
2329 /* The cie_table is discarded by the next if. */
2332 if (cie_table.num_entries != 0)
2334 /* Reinit cie_table: debug_frame has different CIEs. */
2335 xfree (cie_table.entries);
2336 cie_table.num_entries = 0;
2337 cie_table.entries = NULL;
2342 dwarf2_get_section_info (objfile, DWARF2_DEBUG_FRAME,
2343 &unit->dwarf_frame_section,
2344 &unit->dwarf_frame_buffer,
2345 &unit->dwarf_frame_size);
2346 if (unit->dwarf_frame_size)
2348 int num_old_fde_entries = fde_table.num_entries;
2350 TRY_CATCH (e, RETURN_MASK_ERROR)
2352 frame_ptr = unit->dwarf_frame_buffer;
2353 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2354 frame_ptr = decode_frame_entry (unit, frame_ptr, 0,
2355 &cie_table, &fde_table,
2356 EH_CIE_OR_FDE_TYPE_ID);
2360 warning (_("skipping .debug_frame info of %s: %s"),
2361 objfile_name (objfile), e.message);
2363 if (fde_table.num_entries != 0)
2365 fde_table.num_entries = num_old_fde_entries;
2366 if (num_old_fde_entries == 0)
2368 xfree (fde_table.entries);
2369 fde_table.entries = NULL;
2373 fde_table.entries = xrealloc (fde_table.entries,
2374 fde_table.num_entries *
2375 sizeof (fde_table.entries[0]));
2378 fde_table.num_entries = num_old_fde_entries;
2379 /* The cie_table is discarded by the next if. */
2383 /* Discard the cie_table, it is no longer needed. */
2384 if (cie_table.num_entries != 0)
2386 xfree (cie_table.entries);
2387 cie_table.entries = NULL; /* Paranoia. */
2388 cie_table.num_entries = 0; /* Paranoia. */
2391 /* Copy fde_table to obstack: it is needed at runtime. */
2392 fde_table2 = (struct dwarf2_fde_table *)
2393 obstack_alloc (&objfile->objfile_obstack, sizeof (*fde_table2));
2395 if (fde_table.num_entries == 0)
2397 fde_table2->entries = NULL;
2398 fde_table2->num_entries = 0;
2402 struct dwarf2_fde *fde_prev = NULL;
2403 struct dwarf2_fde *first_non_zero_fde = NULL;
2406 /* Prepare FDE table for lookups. */
2407 qsort (fde_table.entries, fde_table.num_entries,
2408 sizeof (fde_table.entries[0]), qsort_fde_cmp);
2410 /* Check for leftovers from --gc-sections. The GNU linker sets
2411 the relevant symbols to zero, but doesn't zero the FDE *end*
2412 ranges because there's no relocation there. It's (offset,
2413 length), not (start, end). On targets where address zero is
2414 just another valid address this can be a problem, since the
2415 FDEs appear to be non-empty in the output --- we could pick
2416 out the wrong FDE. To work around this, when overlaps are
2417 detected, we prefer FDEs that do not start at zero.
2419 Start by finding the first FDE with non-zero start. Below
2420 we'll discard all FDEs that start at zero and overlap this
2422 for (i = 0; i < fde_table.num_entries; i++)
2424 struct dwarf2_fde *fde = fde_table.entries[i];
2426 if (fde->initial_location != 0)
2428 first_non_zero_fde = fde;
2433 /* Since we'll be doing bsearch, squeeze out identical (except
2434 for eh_frame_p) fde entries so bsearch result is predictable.
2435 Also discard leftovers from --gc-sections. */
2436 fde_table2->num_entries = 0;
2437 for (i = 0; i < fde_table.num_entries; i++)
2439 struct dwarf2_fde *fde = fde_table.entries[i];
2441 if (fde->initial_location == 0
2442 && first_non_zero_fde != NULL
2443 && (first_non_zero_fde->initial_location
2444 < fde->initial_location + fde->address_range))
2447 if (fde_prev != NULL
2448 && fde_prev->initial_location == fde->initial_location)
2451 obstack_grow (&objfile->objfile_obstack, &fde_table.entries[i],
2452 sizeof (fde_table.entries[0]));
2453 ++fde_table2->num_entries;
2456 fde_table2->entries = obstack_finish (&objfile->objfile_obstack);
2458 /* Discard the original fde_table. */
2459 xfree (fde_table.entries);
2462 set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2);
2465 /* Provide a prototype to silence -Wmissing-prototypes. */
2466 void _initialize_dwarf2_frame (void);
2469 _initialize_dwarf2_frame (void)
2471 dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
2472 dwarf2_frame_objfile_data = register_objfile_data ();