1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009
4 Free Software Foundation, Inc.
6 Contributed by Mark Kettenis.
8 This file is part of GDB.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "dwarf2expr.h"
27 #include "frame-base.h"
28 #include "frame-unwind.h"
36 #include "gdb_assert.h"
37 #include "gdb_string.h"
39 #include "complaints.h"
40 #include "dwarf2-frame.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 gdb_byte *initial_instructions;
71 /* Saved augmentation, in case it's needed later. */
74 /* Encoding of addresses. */
77 /* Target address size in bytes. */
80 /* True if a 'z' augmentation existed. */
81 unsigned char saw_z_augmentation;
83 /* True if an 'S' augmentation existed. */
84 unsigned char signal_frame;
86 /* The version recorded in the CIE. */
87 unsigned char version;
90 struct dwarf2_cie_table
93 struct dwarf2_cie **entries;
96 /* Frame Description Entry (FDE). */
100 /* CIE for this FDE. */
101 struct dwarf2_cie *cie;
103 /* First location associated with this FDE. */
104 CORE_ADDR initial_location;
106 /* Number of bytes of program instructions described by this FDE. */
107 CORE_ADDR address_range;
109 /* Instruction sequence. */
110 gdb_byte *instructions;
113 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
115 unsigned char eh_frame_p;
118 struct dwarf2_fde_table
121 struct dwarf2_fde **entries;
124 /* A minimal decoding of DWARF2 compilation units. We only decode
125 what's needed to get to the call frame information. */
129 /* Keep the bfd convenient. */
132 struct objfile *objfile;
134 /* Pointer to the .debug_frame section loaded into memory. */
135 gdb_byte *dwarf_frame_buffer;
137 /* Length of the loaded .debug_frame section. */
138 bfd_size_type dwarf_frame_size;
140 /* Pointer to the .debug_frame section. */
141 asection *dwarf_frame_section;
143 /* Base for DW_EH_PE_datarel encodings. */
146 /* Base for DW_EH_PE_textrel encodings. */
150 static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc);
152 static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum,
155 static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
156 int ptr_len, gdb_byte *buf,
157 unsigned int *bytes_read_ptr,
158 CORE_ADDR func_base);
161 /* Structure describing a frame state. */
163 struct dwarf2_frame_state
165 /* Each register save state can be described in terms of a CFA slot,
166 another register, or a location expression. */
167 struct dwarf2_frame_state_reg_info
169 struct dwarf2_frame_state_reg *reg;
181 /* Used to implement DW_CFA_remember_state. */
182 struct dwarf2_frame_state_reg_info *prev;
185 /* The PC described by the current frame state. */
188 /* Initial register set from the CIE.
189 Used to implement DW_CFA_restore. */
190 struct dwarf2_frame_state_reg_info initial;
192 /* The information we care about from the CIE. */
195 ULONGEST retaddr_column;
197 /* Flags for known producer quirks. */
199 /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa
200 and DW_CFA_def_cfa_offset takes a factored offset. */
201 int armcc_cfa_offsets_sf;
203 /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
204 the CFA is defined as REG - OFFSET rather than REG + OFFSET. */
205 int armcc_cfa_offsets_reversed;
208 /* Store the length the expression for the CFA in the `cfa_reg' field,
209 which is unused in that case. */
210 #define cfa_exp_len cfa_reg
212 /* Assert that the register set RS is large enough to store gdbarch_num_regs
213 columns. If necessary, enlarge the register set. */
216 dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs,
219 size_t size = sizeof (struct dwarf2_frame_state_reg);
221 if (num_regs <= rs->num_regs)
224 rs->reg = (struct dwarf2_frame_state_reg *)
225 xrealloc (rs->reg, num_regs * size);
227 /* Initialize newly allocated registers. */
228 memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size);
229 rs->num_regs = num_regs;
232 /* Copy the register columns in register set RS into newly allocated
233 memory and return a pointer to this newly created copy. */
235 static struct dwarf2_frame_state_reg *
236 dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs)
238 size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg);
239 struct dwarf2_frame_state_reg *reg;
241 reg = (struct dwarf2_frame_state_reg *) xmalloc (size);
242 memcpy (reg, rs->reg, size);
247 /* Release the memory allocated to register set RS. */
250 dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs)
254 dwarf2_frame_state_free_regs (rs->prev);
261 /* Release the memory allocated to the frame state FS. */
264 dwarf2_frame_state_free (void *p)
266 struct dwarf2_frame_state *fs = p;
268 dwarf2_frame_state_free_regs (fs->initial.prev);
269 dwarf2_frame_state_free_regs (fs->regs.prev);
270 xfree (fs->initial.reg);
271 xfree (fs->regs.reg);
276 /* Helper functions for execute_stack_op. */
279 read_reg (void *baton, int reg)
281 struct frame_info *this_frame = (struct frame_info *) baton;
282 struct gdbarch *gdbarch = get_frame_arch (this_frame);
286 regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
288 buf = alloca (register_size (gdbarch, regnum));
289 get_frame_register (this_frame, regnum, buf);
291 /* Convert the register to an integer. This returns a LONGEST
292 rather than a CORE_ADDR, but unpack_pointer does the same thing
293 under the covers, and this makes more sense for non-pointer
294 registers. Maybe read_reg and the associated interfaces should
295 deal with "struct value" instead of CORE_ADDR. */
296 return unpack_long (register_type (gdbarch, regnum), buf);
300 read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
302 read_memory (addr, buf, len);
306 no_get_frame_base (void *baton, gdb_byte **start, size_t *length)
308 internal_error (__FILE__, __LINE__,
309 _("Support for DW_OP_fbreg is unimplemented"));
312 /* Helper function for execute_stack_op. */
315 no_get_frame_cfa (void *baton)
317 internal_error (__FILE__, __LINE__,
318 _("Support for DW_OP_call_frame_cfa is unimplemented"));
322 no_get_tls_address (void *baton, CORE_ADDR offset)
324 internal_error (__FILE__, __LINE__,
325 _("Support for DW_OP_GNU_push_tls_address is unimplemented"));
328 /* Execute the required actions for both the DW_CFA_restore and
329 DW_CFA_restore_extended instructions. */
331 dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
332 struct dwarf2_frame_state *fs, int eh_frame_p)
336 gdb_assert (fs->initial.reg);
337 reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
338 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
340 /* Check if this register was explicitly initialized in the
341 CIE initial instructions. If not, default the rule to
343 if (reg < fs->initial.num_regs)
344 fs->regs.reg[reg] = fs->initial.reg[reg];
346 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;
348 if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED)
349 complaint (&symfile_complaints, _("\
350 incomplete CFI data; DW_CFA_restore unspecified\n\
351 register %s (#%d) at %s"),
352 gdbarch_register_name
353 (gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)),
354 gdbarch_dwarf2_reg_to_regnum (gdbarch, reg),
355 paddress (gdbarch, fs->pc));
359 execute_stack_op (gdb_byte *exp, ULONGEST len, int addr_size,
360 struct frame_info *this_frame, CORE_ADDR initial)
362 struct dwarf_expr_context *ctx;
364 struct cleanup *old_chain;
366 ctx = new_dwarf_expr_context ();
367 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
369 ctx->gdbarch = get_frame_arch (this_frame);
370 ctx->addr_size = addr_size;
371 ctx->baton = this_frame;
372 ctx->read_reg = read_reg;
373 ctx->read_mem = read_mem;
374 ctx->get_frame_base = no_get_frame_base;
375 ctx->get_frame_cfa = no_get_frame_cfa;
376 ctx->get_tls_address = no_get_tls_address;
378 dwarf_expr_push (ctx, initial);
379 dwarf_expr_eval (ctx, exp, len);
380 result = dwarf_expr_fetch (ctx, 0);
382 if (ctx->location == DWARF_VALUE_REGISTER)
383 result = read_reg (this_frame, result);
384 else if (ctx->location != DWARF_VALUE_MEMORY)
386 /* This is actually invalid DWARF, but if we ever do run across
387 it somehow, we might as well support it. So, instead, report
388 it as unimplemented. */
389 error (_("Not implemented: computing unwound register using explicit value operator"));
392 do_cleanups (old_chain);
399 execute_cfa_program (struct dwarf2_fde *fde, gdb_byte *insn_ptr,
400 gdb_byte *insn_end, struct frame_info *this_frame,
401 struct dwarf2_frame_state *fs)
403 int eh_frame_p = fde->eh_frame_p;
404 CORE_ADDR pc = get_frame_pc (this_frame);
406 struct gdbarch *gdbarch = get_frame_arch (this_frame);
407 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
409 while (insn_ptr < insn_end && fs->pc <= pc)
411 gdb_byte insn = *insn_ptr++;
415 if ((insn & 0xc0) == DW_CFA_advance_loc)
416 fs->pc += (insn & 0x3f) * fs->code_align;
417 else if ((insn & 0xc0) == DW_CFA_offset)
420 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
421 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
422 offset = utmp * fs->data_align;
423 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
424 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
425 fs->regs.reg[reg].loc.offset = offset;
427 else if ((insn & 0xc0) == DW_CFA_restore)
430 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
437 fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
438 fde->cie->addr_size, insn_ptr,
439 &bytes_read, fde->initial_location);
440 /* Apply the objfile offset for relocatable objects. */
441 fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets,
442 SECT_OFF_TEXT (fde->cie->unit->objfile));
443 insn_ptr += bytes_read;
446 case DW_CFA_advance_loc1:
447 utmp = extract_unsigned_integer (insn_ptr, 1, byte_order);
448 fs->pc += utmp * fs->code_align;
451 case DW_CFA_advance_loc2:
452 utmp = extract_unsigned_integer (insn_ptr, 2, byte_order);
453 fs->pc += utmp * fs->code_align;
456 case DW_CFA_advance_loc4:
457 utmp = extract_unsigned_integer (insn_ptr, 4, byte_order);
458 fs->pc += utmp * fs->code_align;
462 case DW_CFA_offset_extended:
463 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
464 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
465 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
466 offset = utmp * fs->data_align;
467 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
468 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
469 fs->regs.reg[reg].loc.offset = offset;
472 case DW_CFA_restore_extended:
473 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
474 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
477 case DW_CFA_undefined:
478 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
479 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
480 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
481 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
484 case DW_CFA_same_value:
485 insn_ptr = 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_SAME_VALUE;
491 case DW_CFA_register:
492 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
493 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
494 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
495 utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p);
496 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
497 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
498 fs->regs.reg[reg].loc.reg = utmp;
501 case DW_CFA_remember_state:
503 struct dwarf2_frame_state_reg_info *new_rs;
505 new_rs = XMALLOC (struct dwarf2_frame_state_reg_info);
507 fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs);
508 fs->regs.prev = new_rs;
512 case DW_CFA_restore_state:
514 struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;
518 complaint (&symfile_complaints, _("\
519 bad CFI data; mismatched DW_CFA_restore_state at %s"),
520 paddress (gdbarch, fs->pc));
524 xfree (fs->regs.reg);
532 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
533 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
535 if (fs->armcc_cfa_offsets_sf)
536 utmp *= fs->data_align;
538 fs->regs.cfa_offset = utmp;
539 fs->regs.cfa_how = CFA_REG_OFFSET;
542 case DW_CFA_def_cfa_register:
543 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
544 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch,
547 fs->regs.cfa_how = CFA_REG_OFFSET;
550 case DW_CFA_def_cfa_offset:
551 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
553 if (fs->armcc_cfa_offsets_sf)
554 utmp *= fs->data_align;
556 fs->regs.cfa_offset = utmp;
557 /* cfa_how deliberately not set. */
563 case DW_CFA_def_cfa_expression:
564 insn_ptr = read_uleb128 (insn_ptr, insn_end,
565 &fs->regs.cfa_exp_len);
566 fs->regs.cfa_exp = insn_ptr;
567 fs->regs.cfa_how = CFA_EXP;
568 insn_ptr += fs->regs.cfa_exp_len;
571 case DW_CFA_expression:
572 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
573 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
574 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
575 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
576 fs->regs.reg[reg].loc.exp = insn_ptr;
577 fs->regs.reg[reg].exp_len = utmp;
578 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
582 case DW_CFA_offset_extended_sf:
583 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
584 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
585 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
586 offset *= fs->data_align;
587 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
588 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
589 fs->regs.reg[reg].loc.offset = offset;
592 case DW_CFA_val_offset:
593 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
594 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
595 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
596 offset = utmp * fs->data_align;
597 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
598 fs->regs.reg[reg].loc.offset = offset;
601 case DW_CFA_val_offset_sf:
602 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
603 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
604 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
605 offset *= fs->data_align;
606 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
607 fs->regs.reg[reg].loc.offset = offset;
610 case DW_CFA_val_expression:
611 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
612 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
613 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
614 fs->regs.reg[reg].loc.exp = insn_ptr;
615 fs->regs.reg[reg].exp_len = utmp;
616 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP;
620 case DW_CFA_def_cfa_sf:
621 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
622 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch,
625 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
626 fs->regs.cfa_offset = offset * fs->data_align;
627 fs->regs.cfa_how = CFA_REG_OFFSET;
630 case DW_CFA_def_cfa_offset_sf:
631 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
632 fs->regs.cfa_offset = offset * fs->data_align;
633 /* cfa_how deliberately not set. */
636 case DW_CFA_GNU_window_save:
637 /* This is SPARC-specific code, and contains hard-coded
638 constants for the register numbering scheme used by
639 GCC. Rather than having a architecture-specific
640 operation that's only ever used by a single
641 architecture, we provide the implementation here.
642 Incidentally that's what GCC does too in its
645 int size = register_size (gdbarch, 0);
646 dwarf2_frame_state_alloc_regs (&fs->regs, 32);
647 for (reg = 8; reg < 16; reg++)
649 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
650 fs->regs.reg[reg].loc.reg = reg + 16;
652 for (reg = 16; reg < 32; reg++)
654 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
655 fs->regs.reg[reg].loc.offset = (reg - 16) * size;
660 case DW_CFA_GNU_args_size:
662 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
665 case DW_CFA_GNU_negative_offset_extended:
666 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
667 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
668 insn_ptr = read_uleb128 (insn_ptr, insn_end, &offset);
669 offset *= fs->data_align;
670 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
671 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
672 fs->regs.reg[reg].loc.offset = -offset;
676 internal_error (__FILE__, __LINE__, _("Unknown CFI encountered."));
681 /* Don't allow remember/restore between CIE and FDE programs. */
682 dwarf2_frame_state_free_regs (fs->regs.prev);
683 fs->regs.prev = NULL;
687 /* Architecture-specific operations. */
689 /* Per-architecture data key. */
690 static struct gdbarch_data *dwarf2_frame_data;
692 struct dwarf2_frame_ops
694 /* Pre-initialize the register state REG for register REGNUM. */
695 void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *,
696 struct frame_info *);
698 /* Check whether the THIS_FRAME is a signal trampoline. */
699 int (*signal_frame_p) (struct gdbarch *, struct frame_info *);
701 /* Convert .eh_frame register number to DWARF register number, or
702 adjust .debug_frame register number. */
703 int (*adjust_regnum) (struct gdbarch *, int, int);
706 /* Default architecture-specific register state initialization
710 dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
711 struct dwarf2_frame_state_reg *reg,
712 struct frame_info *this_frame)
714 /* If we have a register that acts as a program counter, mark it as
715 a destination for the return address. If we have a register that
716 serves as the stack pointer, arrange for it to be filled with the
717 call frame address (CFA). The other registers are marked as
720 We copy the return address to the program counter, since many
721 parts in GDB assume that it is possible to get the return address
722 by unwinding the program counter register. However, on ISA's
723 with a dedicated return address register, the CFI usually only
724 contains information to unwind that return address register.
726 The reason we're treating the stack pointer special here is
727 because in many cases GCC doesn't emit CFI for the stack pointer
728 and implicitly assumes that it is equal to the CFA. This makes
729 some sense since the DWARF specification (version 3, draft 8,
732 "Typically, the CFA is defined to be the value of the stack
733 pointer at the call site in the previous frame (which may be
734 different from its value on entry to the current frame)."
736 However, this isn't true for all platforms supported by GCC
737 (e.g. IBM S/390 and zSeries). Those architectures should provide
738 their own architecture-specific initialization function. */
740 if (regnum == gdbarch_pc_regnum (gdbarch))
741 reg->how = DWARF2_FRAME_REG_RA;
742 else if (regnum == gdbarch_sp_regnum (gdbarch))
743 reg->how = DWARF2_FRAME_REG_CFA;
746 /* Return a default for the architecture-specific operations. */
749 dwarf2_frame_init (struct obstack *obstack)
751 struct dwarf2_frame_ops *ops;
753 ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
754 ops->init_reg = dwarf2_frame_default_init_reg;
758 /* Set the architecture-specific register state initialization
759 function for GDBARCH to INIT_REG. */
762 dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
763 void (*init_reg) (struct gdbarch *, int,
764 struct dwarf2_frame_state_reg *,
765 struct frame_info *))
767 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
769 ops->init_reg = init_reg;
772 /* Pre-initialize the register state REG for register REGNUM. */
775 dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
776 struct dwarf2_frame_state_reg *reg,
777 struct frame_info *this_frame)
779 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
781 ops->init_reg (gdbarch, regnum, reg, this_frame);
784 /* Set the architecture-specific signal trampoline recognition
785 function for GDBARCH to SIGNAL_FRAME_P. */
788 dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
789 int (*signal_frame_p) (struct gdbarch *,
790 struct frame_info *))
792 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
794 ops->signal_frame_p = signal_frame_p;
797 /* Query the architecture-specific signal frame recognizer for
801 dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
802 struct frame_info *this_frame)
804 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
806 if (ops->signal_frame_p == NULL)
808 return ops->signal_frame_p (gdbarch, this_frame);
811 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
815 dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
816 int (*adjust_regnum) (struct gdbarch *,
819 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
821 ops->adjust_regnum = adjust_regnum;
824 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
828 dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum, int eh_frame_p)
830 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
832 if (ops->adjust_regnum == NULL)
834 return ops->adjust_regnum (gdbarch, regnum, eh_frame_p);
838 dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
839 struct dwarf2_fde *fde)
841 static const char *arm_idents[] = {
842 "ARM C Compiler, ADS",
843 "Thumb C Compiler, ADS",
844 "ARM C++ Compiler, ADS",
845 "Thumb C++ Compiler, ADS",
846 "ARM/Thumb C/C++ Compiler, RVCT"
852 s = find_pc_symtab (fs->pc);
853 if (s == NULL || s->producer == NULL)
856 for (i = 0; i < ARRAY_SIZE (arm_idents); i++)
857 if (strncmp (s->producer, arm_idents[i], strlen (arm_idents[i])) == 0)
859 if (fde->cie->version == 1)
860 fs->armcc_cfa_offsets_sf = 1;
862 if (fde->cie->version == 1)
863 fs->armcc_cfa_offsets_reversed = 1;
865 /* The reversed offset problem is present in some compilers
866 using DWARF3, but it was eventually fixed. Check the ARM
867 defined augmentations, which are in the format "armcc" followed
868 by a list of one-character options. The "+" option means
869 this problem is fixed (no quirk needed). If the armcc
870 augmentation is missing, the quirk is needed. */
871 if (fde->cie->version == 3
872 && (strncmp (fde->cie->augmentation, "armcc", 5) != 0
873 || strchr (fde->cie->augmentation + 5, '+') == NULL))
874 fs->armcc_cfa_offsets_reversed = 1;
881 struct dwarf2_frame_cache
883 /* DWARF Call Frame Address. */
886 /* Set if the return address column was marked as undefined. */
887 int undefined_retaddr;
889 /* Saved registers, indexed by GDB register number, not by DWARF
891 struct dwarf2_frame_state_reg *reg;
893 /* Return address register. */
894 struct dwarf2_frame_state_reg retaddr_reg;
896 /* Target address size in bytes. */
900 static struct dwarf2_frame_cache *
901 dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
903 struct cleanup *old_chain;
904 struct gdbarch *gdbarch = get_frame_arch (this_frame);
905 const int num_regs = gdbarch_num_regs (gdbarch)
906 + gdbarch_num_pseudo_regs (gdbarch);
907 struct dwarf2_frame_cache *cache;
908 struct dwarf2_frame_state *fs;
909 struct dwarf2_fde *fde;
914 /* Allocate a new cache. */
915 cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
916 cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
918 /* Allocate and initialize the frame state. */
919 fs = XMALLOC (struct dwarf2_frame_state);
920 memset (fs, 0, sizeof (struct dwarf2_frame_state));
921 old_chain = make_cleanup (dwarf2_frame_state_free, fs);
925 Note that if the next frame is never supposed to return (i.e. a call
926 to abort), the compiler might optimize away the instruction at
927 its return address. As a result the return address will
928 point at some random instruction, and the CFI for that
929 instruction is probably worthless to us. GCC's unwinder solves
930 this problem by substracting 1 from the return address to get an
931 address in the middle of a presumed call instruction (or the
932 instruction in the associated delay slot). This should only be
933 done for "normal" frames and not for resume-type frames (signal
934 handlers, sentinel frames, dummy frames). The function
935 get_frame_address_in_block does just this. It's not clear how
936 reliable the method is though; there is the potential for the
937 register state pre-call being different to that on return. */
938 fs->pc = get_frame_address_in_block (this_frame);
940 /* Find the correct FDE. */
941 fde = dwarf2_frame_find_fde (&fs->pc);
942 gdb_assert (fde != NULL);
944 /* Extract any interesting information from the CIE. */
945 fs->data_align = fde->cie->data_alignment_factor;
946 fs->code_align = fde->cie->code_alignment_factor;
947 fs->retaddr_column = fde->cie->return_address_register;
948 cache->addr_size = fde->cie->addr_size;
950 /* Check for "quirks" - known bugs in producers. */
951 dwarf2_frame_find_quirks (fs, fde);
953 /* First decode all the insns in the CIE. */
954 execute_cfa_program (fde, fde->cie->initial_instructions,
955 fde->cie->end, this_frame, fs);
957 /* Save the initialized register set. */
958 fs->initial = fs->regs;
959 fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs);
961 /* Then decode the insns in the FDE up to our target PC. */
962 execute_cfa_program (fde, fde->instructions, fde->end, this_frame, fs);
964 /* Calculate the CFA. */
965 switch (fs->regs.cfa_how)
968 cache->cfa = read_reg (this_frame, fs->regs.cfa_reg);
969 if (fs->armcc_cfa_offsets_reversed)
970 cache->cfa -= fs->regs.cfa_offset;
972 cache->cfa += fs->regs.cfa_offset;
977 execute_stack_op (fs->regs.cfa_exp, fs->regs.cfa_exp_len,
978 cache->addr_size, this_frame, 0);
982 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
985 /* Initialize the register state. */
989 for (regnum = 0; regnum < num_regs; regnum++)
990 dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame);
993 /* Go through the DWARF2 CFI generated table and save its register
994 location information in the cache. Note that we don't skip the
995 return address column; it's perfectly all right for it to
996 correspond to a real register. If it doesn't correspond to a
997 real register, or if we shouldn't treat it as such,
998 gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside
999 the range [0, gdbarch_num_regs). */
1001 int column; /* CFI speak for "register number". */
1003 for (column = 0; column < fs->regs.num_regs; column++)
1005 /* Use the GDB register number as the destination index. */
1006 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, column);
1008 /* If there's no corresponding GDB register, ignore it. */
1009 if (regnum < 0 || regnum >= num_regs)
1012 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1013 of all debug info registers. If it doesn't, complain (but
1014 not too loudly). It turns out that GCC assumes that an
1015 unspecified register implies "same value" when CFI (draft
1016 7) specifies nothing at all. Such a register could equally
1017 be interpreted as "undefined". Also note that this check
1018 isn't sufficient; it only checks that all registers in the
1019 range [0 .. max column] are specified, and won't detect
1020 problems when a debug info register falls outside of the
1021 table. We need a way of iterating through all the valid
1022 DWARF2 register numbers. */
1023 if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
1025 if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED)
1026 complaint (&symfile_complaints, _("\
1027 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1028 gdbarch_register_name (gdbarch, regnum),
1029 paddress (gdbarch, fs->pc));
1032 cache->reg[regnum] = fs->regs.reg[column];
1036 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1037 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1041 for (regnum = 0; regnum < num_regs; regnum++)
1043 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
1044 || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
1046 struct dwarf2_frame_state_reg *retaddr_reg =
1047 &fs->regs.reg[fs->retaddr_column];
1049 /* It seems rather bizarre to specify an "empty" column as
1050 the return adress column. However, this is exactly
1051 what GCC does on some targets. It turns out that GCC
1052 assumes that the return address can be found in the
1053 register corresponding to the return address column.
1054 Incidentally, that's how we should treat a return
1055 address column specifying "same value" too. */
1056 if (fs->retaddr_column < fs->regs.num_regs
1057 && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
1058 && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
1060 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1061 cache->reg[regnum] = *retaddr_reg;
1063 cache->retaddr_reg = *retaddr_reg;
1067 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1069 cache->reg[regnum].loc.reg = fs->retaddr_column;
1070 cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
1074 cache->retaddr_reg.loc.reg = fs->retaddr_column;
1075 cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG;
1082 if (fs->retaddr_column < fs->regs.num_regs
1083 && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
1084 cache->undefined_retaddr = 1;
1086 do_cleanups (old_chain);
1088 *this_cache = cache;
1093 dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
1094 struct frame_id *this_id)
1096 struct dwarf2_frame_cache *cache =
1097 dwarf2_frame_cache (this_frame, this_cache);
1099 if (cache->undefined_retaddr)
1102 (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
1105 static struct value *
1106 dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache,
1109 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1110 struct dwarf2_frame_cache *cache =
1111 dwarf2_frame_cache (this_frame, this_cache);
1115 switch (cache->reg[regnum].how)
1117 case DWARF2_FRAME_REG_UNDEFINED:
1118 /* If CFI explicitly specified that the value isn't defined,
1119 mark it as optimized away; the value isn't available. */
1120 return frame_unwind_got_optimized (this_frame, regnum);
1122 case DWARF2_FRAME_REG_SAVED_OFFSET:
1123 addr = cache->cfa + cache->reg[regnum].loc.offset;
1124 return frame_unwind_got_memory (this_frame, regnum, addr);
1126 case DWARF2_FRAME_REG_SAVED_REG:
1128 = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg);
1129 return frame_unwind_got_register (this_frame, regnum, realnum);
1131 case DWARF2_FRAME_REG_SAVED_EXP:
1132 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1133 cache->reg[regnum].exp_len,
1134 cache->addr_size, this_frame, cache->cfa);
1135 return frame_unwind_got_memory (this_frame, regnum, addr);
1137 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET:
1138 addr = cache->cfa + cache->reg[regnum].loc.offset;
1139 return frame_unwind_got_constant (this_frame, regnum, addr);
1141 case DWARF2_FRAME_REG_SAVED_VAL_EXP:
1142 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1143 cache->reg[regnum].exp_len,
1144 cache->addr_size, this_frame, cache->cfa);
1145 return frame_unwind_got_constant (this_frame, regnum, addr);
1147 case DWARF2_FRAME_REG_UNSPECIFIED:
1148 /* GCC, in its infinite wisdom decided to not provide unwind
1149 information for registers that are "same value". Since
1150 DWARF2 (3 draft 7) doesn't define such behavior, said
1151 registers are actually undefined (which is different to CFI
1152 "undefined"). Code above issues a complaint about this.
1153 Here just fudge the books, assume GCC, and that the value is
1154 more inner on the stack. */
1155 return frame_unwind_got_register (this_frame, regnum, regnum);
1157 case DWARF2_FRAME_REG_SAME_VALUE:
1158 return frame_unwind_got_register (this_frame, regnum, regnum);
1160 case DWARF2_FRAME_REG_CFA:
1161 return frame_unwind_got_address (this_frame, regnum, cache->cfa);
1163 case DWARF2_FRAME_REG_CFA_OFFSET:
1164 addr = cache->cfa + cache->reg[regnum].loc.offset;
1165 return frame_unwind_got_address (this_frame, regnum, addr);
1167 case DWARF2_FRAME_REG_RA_OFFSET:
1168 addr = cache->reg[regnum].loc.offset;
1169 regnum = gdbarch_dwarf2_reg_to_regnum
1170 (gdbarch, cache->retaddr_reg.loc.reg);
1171 addr += get_frame_register_unsigned (this_frame, regnum);
1172 return frame_unwind_got_address (this_frame, regnum, addr);
1174 case DWARF2_FRAME_REG_FN:
1175 return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum);
1178 internal_error (__FILE__, __LINE__, _("Unknown register rule."));
1183 dwarf2_frame_sniffer (const struct frame_unwind *self,
1184 struct frame_info *this_frame, void **this_cache)
1186 /* Grab an address that is guarenteed to reside somewhere within the
1187 function. get_frame_pc(), with a no-return next function, can
1188 end up returning something past the end of this function's body.
1189 If the frame we're sniffing for is a signal frame whose start
1190 address is placed on the stack by the OS, its FDE must
1191 extend one byte before its start address or we could potentially
1192 select the FDE of the previous function. */
1193 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1194 struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr);
1198 /* On some targets, signal trampolines may have unwind information.
1199 We need to recognize them so that we set the frame type
1202 if (fde->cie->signal_frame
1203 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame),
1205 return self->type == SIGTRAMP_FRAME;
1207 return self->type != SIGTRAMP_FRAME;
1210 static const struct frame_unwind dwarf2_frame_unwind =
1213 dwarf2_frame_this_id,
1214 dwarf2_frame_prev_register,
1216 dwarf2_frame_sniffer
1219 static const struct frame_unwind dwarf2_signal_frame_unwind =
1222 dwarf2_frame_this_id,
1223 dwarf2_frame_prev_register,
1225 dwarf2_frame_sniffer
1228 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1231 dwarf2_append_unwinders (struct gdbarch *gdbarch)
1233 frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind);
1234 frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind);
1238 /* There is no explicitly defined relationship between the CFA and the
1239 location of frame's local variables and arguments/parameters.
1240 Therefore, frame base methods on this page should probably only be
1241 used as a last resort, just to avoid printing total garbage as a
1242 response to the "info frame" command. */
1245 dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache)
1247 struct dwarf2_frame_cache *cache =
1248 dwarf2_frame_cache (this_frame, this_cache);
1253 static const struct frame_base dwarf2_frame_base =
1255 &dwarf2_frame_unwind,
1256 dwarf2_frame_base_address,
1257 dwarf2_frame_base_address,
1258 dwarf2_frame_base_address
1261 const struct frame_base *
1262 dwarf2_frame_base_sniffer (struct frame_info *this_frame)
1264 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1265 if (dwarf2_frame_find_fde (&block_addr))
1266 return &dwarf2_frame_base;
1271 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1272 the DWARF unwinder. This is used to implement
1273 DW_OP_call_frame_cfa. */
1276 dwarf2_frame_cfa (struct frame_info *this_frame)
1278 while (get_frame_type (this_frame) == INLINE_FRAME)
1279 this_frame = get_prev_frame (this_frame);
1280 /* This restriction could be lifted if other unwinders are known to
1281 compute the frame base in a way compatible with the DWARF
1283 if (! frame_unwinder_is (this_frame, &dwarf2_frame_unwind))
1284 error (_("can't compute CFA for this frame"));
1285 return get_frame_base (this_frame);
1288 const struct objfile_data *dwarf2_frame_objfile_data;
1291 read_1_byte (bfd *abfd, gdb_byte *buf)
1293 return bfd_get_8 (abfd, buf);
1297 read_4_bytes (bfd *abfd, gdb_byte *buf)
1299 return bfd_get_32 (abfd, buf);
1303 read_8_bytes (bfd *abfd, gdb_byte *buf)
1305 return bfd_get_64 (abfd, buf);
1309 read_unsigned_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1312 unsigned int num_read;
1322 byte = bfd_get_8 (abfd, (bfd_byte *) buf);
1325 result |= ((byte & 0x7f) << shift);
1328 while (byte & 0x80);
1330 *bytes_read_ptr = num_read;
1336 read_signed_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1340 unsigned int num_read;
1349 byte = bfd_get_8 (abfd, (bfd_byte *) buf);
1352 result |= ((byte & 0x7f) << shift);
1355 while (byte & 0x80);
1357 if (shift < 8 * sizeof (result) && (byte & 0x40))
1358 result |= -(((LONGEST)1) << shift);
1360 *bytes_read_ptr = num_read;
1366 read_initial_length (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1370 result = bfd_get_32 (abfd, buf);
1371 if (result == 0xffffffff)
1373 result = bfd_get_64 (abfd, buf + 4);
1374 *bytes_read_ptr = 12;
1377 *bytes_read_ptr = 4;
1383 /* Pointer encoding helper functions. */
1385 /* GCC supports exception handling based on DWARF2 CFI. However, for
1386 technical reasons, it encodes addresses in its FDE's in a different
1387 way. Several "pointer encodings" are supported. The encoding
1388 that's used for a particular FDE is determined by the 'R'
1389 augmentation in the associated CIE. The argument of this
1390 augmentation is a single byte.
1392 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1393 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1394 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1395 address should be interpreted (absolute, relative to the current
1396 position in the FDE, ...). Bit 7, indicates that the address
1397 should be dereferenced. */
1400 encoding_for_size (unsigned int size)
1405 return DW_EH_PE_udata2;
1407 return DW_EH_PE_udata4;
1409 return DW_EH_PE_udata8;
1411 internal_error (__FILE__, __LINE__, _("Unsupported address size"));
1416 read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
1417 int ptr_len, gdb_byte *buf, unsigned int *bytes_read_ptr,
1418 CORE_ADDR func_base)
1423 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1425 if (encoding & DW_EH_PE_indirect)
1426 internal_error (__FILE__, __LINE__,
1427 _("Unsupported encoding: DW_EH_PE_indirect"));
1429 *bytes_read_ptr = 0;
1431 switch (encoding & 0x70)
1433 case DW_EH_PE_absptr:
1436 case DW_EH_PE_pcrel:
1437 base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section);
1438 base += (buf - unit->dwarf_frame_buffer);
1440 case DW_EH_PE_datarel:
1443 case DW_EH_PE_textrel:
1446 case DW_EH_PE_funcrel:
1449 case DW_EH_PE_aligned:
1451 offset = buf - unit->dwarf_frame_buffer;
1452 if ((offset % ptr_len) != 0)
1454 *bytes_read_ptr = ptr_len - (offset % ptr_len);
1455 buf += *bytes_read_ptr;
1459 internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding"));
1462 if ((encoding & 0x07) == 0x00)
1464 encoding |= encoding_for_size (ptr_len);
1465 if (bfd_get_sign_extend_vma (unit->abfd))
1466 encoding |= DW_EH_PE_signed;
1469 switch (encoding & 0x0f)
1471 case DW_EH_PE_uleb128:
1474 gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1475 *bytes_read_ptr += read_uleb128 (buf, end_buf, &value) - buf;
1476 return base + value;
1478 case DW_EH_PE_udata2:
1479 *bytes_read_ptr += 2;
1480 return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf));
1481 case DW_EH_PE_udata4:
1482 *bytes_read_ptr += 4;
1483 return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf));
1484 case DW_EH_PE_udata8:
1485 *bytes_read_ptr += 8;
1486 return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf));
1487 case DW_EH_PE_sleb128:
1490 gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1491 *bytes_read_ptr += read_sleb128 (buf, end_buf, &value) - buf;
1492 return base + value;
1494 case DW_EH_PE_sdata2:
1495 *bytes_read_ptr += 2;
1496 return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf));
1497 case DW_EH_PE_sdata4:
1498 *bytes_read_ptr += 4;
1499 return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf));
1500 case DW_EH_PE_sdata8:
1501 *bytes_read_ptr += 8;
1502 return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf));
1504 internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding"));
1510 bsearch_cie_cmp (const void *key, const void *element)
1512 ULONGEST cie_pointer = *(ULONGEST *) key;
1513 struct dwarf2_cie *cie = *(struct dwarf2_cie **) element;
1515 if (cie_pointer == cie->cie_pointer)
1518 return (cie_pointer < cie->cie_pointer) ? -1 : 1;
1521 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1522 static struct dwarf2_cie *
1523 find_cie (struct dwarf2_cie_table *cie_table, ULONGEST cie_pointer)
1525 struct dwarf2_cie **p_cie;
1527 p_cie = bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries,
1528 sizeof (cie_table->entries[0]), bsearch_cie_cmp);
1534 /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1536 add_cie (struct dwarf2_cie_table *cie_table, struct dwarf2_cie *cie)
1538 const int n = cie_table->num_entries;
1541 || cie_table->entries[n - 1]->cie_pointer < cie->cie_pointer);
1543 cie_table->entries =
1544 xrealloc (cie_table->entries, (n + 1) * sizeof (cie_table->entries[0]));
1545 cie_table->entries[n] = cie;
1546 cie_table->num_entries = n + 1;
1550 bsearch_fde_cmp (const void *key, const void *element)
1552 CORE_ADDR seek_pc = *(CORE_ADDR *) key;
1553 struct dwarf2_fde *fde = *(struct dwarf2_fde **) element;
1554 if (seek_pc < fde->initial_location)
1556 if (seek_pc < fde->initial_location + fde->address_range)
1561 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1562 inital location associated with it into *PC. */
1564 static struct dwarf2_fde *
1565 dwarf2_frame_find_fde (CORE_ADDR *pc)
1567 struct objfile *objfile;
1569 ALL_OBJFILES (objfile)
1571 struct dwarf2_fde_table *fde_table;
1572 struct dwarf2_fde **p_fde;
1576 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1577 if (fde_table == NULL)
1580 gdb_assert (objfile->section_offsets);
1581 offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
1583 gdb_assert (fde_table->num_entries > 0);
1584 if (*pc < offset + fde_table->entries[0]->initial_location)
1587 seek_pc = *pc - offset;
1588 p_fde = bsearch (&seek_pc, fde_table->entries, fde_table->num_entries,
1589 sizeof (fde_table->entries[0]), bsearch_fde_cmp);
1592 *pc = (*p_fde)->initial_location + offset;
1599 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1601 add_fde (struct dwarf2_fde_table *fde_table, struct dwarf2_fde *fde)
1603 if (fde->address_range == 0)
1604 /* Discard useless FDEs. */
1607 fde_table->num_entries += 1;
1608 fde_table->entries =
1609 xrealloc (fde_table->entries,
1610 fde_table->num_entries * sizeof (fde_table->entries[0]));
1611 fde_table->entries[fde_table->num_entries - 1] = fde;
1614 #ifdef CC_HAS_LONG_LONG
1615 #define DW64_CIE_ID 0xffffffffffffffffULL
1617 #define DW64_CIE_ID ~0
1620 static gdb_byte *decode_frame_entry (struct comp_unit *unit, gdb_byte *start,
1622 struct dwarf2_cie_table *cie_table,
1623 struct dwarf2_fde_table *fde_table);
1625 /* Decode the next CIE or FDE. Return NULL if invalid input, otherwise
1626 the next byte to be processed. */
1628 decode_frame_entry_1 (struct comp_unit *unit, gdb_byte *start, int eh_frame_p,
1629 struct dwarf2_cie_table *cie_table,
1630 struct dwarf2_fde_table *fde_table)
1632 struct gdbarch *gdbarch = get_objfile_arch (unit->objfile);
1633 gdb_byte *buf, *end;
1635 unsigned int bytes_read;
1638 ULONGEST cie_pointer;
1641 length = read_initial_length (unit->abfd, buf, &bytes_read);
1645 /* Are we still within the section? */
1646 if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
1652 /* Distinguish between 32 and 64-bit encoded frame info. */
1653 dwarf64_p = (bytes_read == 12);
1655 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1659 cie_id = DW64_CIE_ID;
1665 cie_pointer = read_8_bytes (unit->abfd, buf);
1670 cie_pointer = read_4_bytes (unit->abfd, buf);
1674 if (cie_pointer == cie_id)
1676 /* This is a CIE. */
1677 struct dwarf2_cie *cie;
1679 unsigned int cie_version;
1681 /* Record the offset into the .debug_frame section of this CIE. */
1682 cie_pointer = start - unit->dwarf_frame_buffer;
1684 /* Check whether we've already read it. */
1685 if (find_cie (cie_table, cie_pointer))
1688 cie = (struct dwarf2_cie *)
1689 obstack_alloc (&unit->objfile->objfile_obstack,
1690 sizeof (struct dwarf2_cie));
1691 cie->initial_instructions = NULL;
1692 cie->cie_pointer = cie_pointer;
1694 /* The encoding for FDE's in a normal .debug_frame section
1695 depends on the target address size. */
1696 cie->encoding = DW_EH_PE_absptr;
1698 /* The target address size. For .eh_frame FDEs this is considered
1699 equal to the size of a target pointer. For .dwarf_frame FDEs,
1700 this is supposed to be the target address size from the associated
1701 CU header. FIXME: We do not have a good way to determine the
1702 latter. Always use the target pointer size for now. */
1703 cie->addr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1705 /* We'll determine the final value later, but we need to
1706 initialize it conservatively. */
1707 cie->signal_frame = 0;
1709 /* Check version number. */
1710 cie_version = read_1_byte (unit->abfd, buf);
1711 if (cie_version != 1 && cie_version != 3)
1713 cie->version = cie_version;
1716 /* Interpret the interesting bits of the augmentation. */
1717 cie->augmentation = augmentation = (char *) buf;
1718 buf += (strlen (augmentation) + 1);
1720 /* Ignore armcc augmentations. We only use them for quirks,
1721 and that doesn't happen until later. */
1722 if (strncmp (augmentation, "armcc", 5) == 0)
1723 augmentation += strlen (augmentation);
1725 /* The GCC 2.x "eh" augmentation has a pointer immediately
1726 following the augmentation string, so it must be handled
1728 if (augmentation[0] == 'e' && augmentation[1] == 'h')
1731 buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1735 cie->code_alignment_factor =
1736 read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
1739 cie->data_alignment_factor =
1740 read_signed_leb128 (unit->abfd, buf, &bytes_read);
1743 if (cie_version == 1)
1745 cie->return_address_register = read_1_byte (unit->abfd, buf);
1749 cie->return_address_register = read_unsigned_leb128 (unit->abfd, buf,
1751 cie->return_address_register
1752 = dwarf2_frame_adjust_regnum (gdbarch,
1753 cie->return_address_register,
1758 cie->saw_z_augmentation = (*augmentation == 'z');
1759 if (cie->saw_z_augmentation)
1763 length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
1767 cie->initial_instructions = buf + length;
1771 while (*augmentation)
1773 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1774 if (*augmentation == 'L')
1781 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1782 else if (*augmentation == 'R')
1784 cie->encoding = *buf++;
1788 /* "P" indicates a personality routine in the CIE augmentation. */
1789 else if (*augmentation == 'P')
1791 /* Skip. Avoid indirection since we throw away the result. */
1792 gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect;
1793 read_encoded_value (unit, encoding, cie->addr_size,
1794 buf, &bytes_read, 0);
1799 /* "S" indicates a signal frame, such that the return
1800 address must not be decremented to locate the call frame
1801 info for the previous frame; it might even be the first
1802 instruction of a function, so decrementing it would take
1803 us to a different function. */
1804 else if (*augmentation == 'S')
1806 cie->signal_frame = 1;
1810 /* Otherwise we have an unknown augmentation. Assume that either
1811 there is no augmentation data, or we saw a 'z' prefix. */
1814 if (cie->initial_instructions)
1815 buf = cie->initial_instructions;
1820 cie->initial_instructions = buf;
1824 add_cie (cie_table, cie);
1828 /* This is a FDE. */
1829 struct dwarf2_fde *fde;
1831 /* In an .eh_frame section, the CIE pointer is the delta between the
1832 address within the FDE where the CIE pointer is stored and the
1833 address of the CIE. Convert it to an offset into the .eh_frame
1837 cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
1838 cie_pointer -= (dwarf64_p ? 8 : 4);
1841 /* In either case, validate the result is still within the section. */
1842 if (cie_pointer >= unit->dwarf_frame_size)
1845 fde = (struct dwarf2_fde *)
1846 obstack_alloc (&unit->objfile->objfile_obstack,
1847 sizeof (struct dwarf2_fde));
1848 fde->cie = find_cie (cie_table, cie_pointer);
1849 if (fde->cie == NULL)
1851 decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer,
1852 eh_frame_p, cie_table, fde_table);
1853 fde->cie = find_cie (cie_table, cie_pointer);
1856 gdb_assert (fde->cie != NULL);
1858 fde->initial_location =
1859 read_encoded_value (unit, fde->cie->encoding, fde->cie->addr_size,
1860 buf, &bytes_read, 0);
1863 fde->address_range =
1864 read_encoded_value (unit, fde->cie->encoding & 0x0f,
1865 fde->cie->addr_size, buf, &bytes_read, 0);
1868 /* A 'z' augmentation in the CIE implies the presence of an
1869 augmentation field in the FDE as well. The only thing known
1870 to be in here at present is the LSDA entry for EH. So we
1871 can skip the whole thing. */
1872 if (fde->cie->saw_z_augmentation)
1876 length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
1877 buf += bytes_read + length;
1882 fde->instructions = buf;
1885 fde->eh_frame_p = eh_frame_p;
1887 add_fde (fde_table, fde);
1893 /* Read a CIE or FDE in BUF and decode it. */
1895 decode_frame_entry (struct comp_unit *unit, gdb_byte *start, int eh_frame_p,
1896 struct dwarf2_cie_table *cie_table,
1897 struct dwarf2_fde_table *fde_table)
1899 enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
1902 ptrdiff_t start_offset;
1906 ret = decode_frame_entry_1 (unit, start, eh_frame_p,
1907 cie_table, fde_table);
1911 /* We have corrupt input data of some form. */
1913 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
1914 and mismatches wrt padding and alignment of debug sections. */
1915 /* Note that there is no requirement in the standard for any
1916 alignment at all in the frame unwind sections. Testing for
1917 alignment before trying to interpret data would be incorrect.
1919 However, GCC traditionally arranged for frame sections to be
1920 sized such that the FDE length and CIE fields happen to be
1921 aligned (in theory, for performance). This, unfortunately,
1922 was done with .align directives, which had the side effect of
1923 forcing the section to be aligned by the linker.
1925 This becomes a problem when you have some other producer that
1926 creates frame sections that are not as strictly aligned. That
1927 produces a hole in the frame info that gets filled by the
1930 The GCC behaviour is arguably a bug, but it's effectively now
1931 part of the ABI, so we're now stuck with it, at least at the
1932 object file level. A smart linker may decide, in the process
1933 of compressing duplicate CIE information, that it can rewrite
1934 the entire output section without this extra padding. */
1936 start_offset = start - unit->dwarf_frame_buffer;
1937 if (workaround < ALIGN4 && (start_offset & 3) != 0)
1939 start += 4 - (start_offset & 3);
1940 workaround = ALIGN4;
1943 if (workaround < ALIGN8 && (start_offset & 7) != 0)
1945 start += 8 - (start_offset & 7);
1946 workaround = ALIGN8;
1950 /* Nothing left to try. Arrange to return as if we've consumed
1951 the entire input section. Hopefully we'll get valid info from
1952 the other of .debug_frame/.eh_frame. */
1954 ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
1964 complaint (&symfile_complaints,
1965 _("Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
1966 unit->dwarf_frame_section->owner->filename,
1967 unit->dwarf_frame_section->name);
1971 complaint (&symfile_complaints,
1972 _("Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
1973 unit->dwarf_frame_section->owner->filename,
1974 unit->dwarf_frame_section->name);
1978 complaint (&symfile_complaints,
1979 _("Corrupt data in %s:%s"),
1980 unit->dwarf_frame_section->owner->filename,
1981 unit->dwarf_frame_section->name);
1989 /* Imported from dwarf2read.c. */
1990 extern void dwarf2_get_section_info (struct objfile *, const char *, asection **,
1991 gdb_byte **, bfd_size_type *);
1994 qsort_fde_cmp (const void *a, const void *b)
1996 struct dwarf2_fde *aa = *(struct dwarf2_fde **)a;
1997 struct dwarf2_fde *bb = *(struct dwarf2_fde **)b;
1999 if (aa->initial_location == bb->initial_location)
2001 if (aa->address_range != bb->address_range
2002 && aa->eh_frame_p == 0 && bb->eh_frame_p == 0)
2003 /* Linker bug, e.g. gold/10400.
2004 Work around it by keeping stable sort order. */
2005 return (a < b) ? -1 : 1;
2007 /* Put eh_frame entries after debug_frame ones. */
2008 return aa->eh_frame_p - bb->eh_frame_p;
2011 return (aa->initial_location < bb->initial_location) ? -1 : 1;
2015 dwarf2_build_frame_info (struct objfile *objfile)
2017 struct comp_unit *unit;
2018 gdb_byte *frame_ptr;
2019 struct dwarf2_cie_table cie_table;
2020 struct dwarf2_fde_table fde_table;
2022 cie_table.num_entries = 0;
2023 cie_table.entries = NULL;
2025 fde_table.num_entries = 0;
2026 fde_table.entries = NULL;
2028 /* Build a minimal decoding of the DWARF2 compilation unit. */
2029 unit = (struct comp_unit *) obstack_alloc (&objfile->objfile_obstack,
2030 sizeof (struct comp_unit));
2031 unit->abfd = objfile->obfd;
2032 unit->objfile = objfile;
2036 dwarf2_get_section_info (objfile, ".eh_frame",
2037 &unit->dwarf_frame_section,
2038 &unit->dwarf_frame_buffer,
2039 &unit->dwarf_frame_size);
2040 if (unit->dwarf_frame_size)
2042 asection *got, *txt;
2044 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2045 that is used for the i386/amd64 target, which currently is
2046 the only target in GCC that supports/uses the
2047 DW_EH_PE_datarel encoding. */
2048 got = bfd_get_section_by_name (unit->abfd, ".got");
2050 unit->dbase = got->vma;
2052 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2054 txt = bfd_get_section_by_name (unit->abfd, ".text");
2056 unit->tbase = txt->vma;
2058 frame_ptr = unit->dwarf_frame_buffer;
2059 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2060 frame_ptr = decode_frame_entry (unit, frame_ptr, 1,
2061 &cie_table, &fde_table);
2063 if (cie_table.num_entries != 0)
2065 /* Reinit cie_table: debug_frame has different CIEs. */
2066 xfree (cie_table.entries);
2067 cie_table.num_entries = 0;
2068 cie_table.entries = NULL;
2072 dwarf2_get_section_info (objfile, ".debug_frame",
2073 &unit->dwarf_frame_section,
2074 &unit->dwarf_frame_buffer,
2075 &unit->dwarf_frame_size);
2076 if (unit->dwarf_frame_size)
2078 frame_ptr = unit->dwarf_frame_buffer;
2079 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2080 frame_ptr = decode_frame_entry (unit, frame_ptr, 0,
2081 &cie_table, &fde_table);
2084 /* Discard the cie_table, it is no longer needed. */
2085 if (cie_table.num_entries != 0)
2087 xfree (cie_table.entries);
2088 cie_table.entries = NULL; /* Paranoia. */
2089 cie_table.num_entries = 0; /* Paranoia. */
2092 if (fde_table.num_entries != 0)
2094 struct dwarf2_fde_table *fde_table2;
2097 /* Prepare FDE table for lookups. */
2098 qsort (fde_table.entries, fde_table.num_entries,
2099 sizeof (fde_table.entries[0]), qsort_fde_cmp);
2101 /* Copy fde_table to obstack: it is needed at runtime. */
2102 fde_table2 = (struct dwarf2_fde_table *)
2103 obstack_alloc (&objfile->objfile_obstack, sizeof (*fde_table2));
2105 /* Since we'll be doing bsearch, squeeze out identical (except for
2106 eh_frame_p) fde entries so bsearch result is predictable. */
2107 for (i = 0, j = 0; j < fde_table.num_entries; ++i)
2111 obstack_grow (&objfile->objfile_obstack, &fde_table.entries[j],
2112 sizeof (fde_table.entries[0]));
2113 while (++j < fde_table.num_entries
2114 && (fde_table.entries[k]->initial_location ==
2115 fde_table.entries[j]->initial_location))
2118 fde_table2->entries = obstack_finish (&objfile->objfile_obstack);
2119 fde_table2->num_entries = i;
2120 set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2);
2122 /* Discard the original fde_table. */
2123 xfree (fde_table.entries);
2127 /* Provide a prototype to silence -Wmissing-prototypes. */
2128 void _initialize_dwarf2_frame (void);
2131 _initialize_dwarf2_frame (void)
2133 dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
2134 dwarf2_frame_objfile_data = register_objfile_data ();