1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009, 2010
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;
89 /* The segment size. */
90 unsigned char segment_size;
93 struct dwarf2_cie_table
96 struct dwarf2_cie **entries;
99 /* Frame Description Entry (FDE). */
103 /* CIE for this FDE. */
104 struct dwarf2_cie *cie;
106 /* First location associated with this FDE. */
107 CORE_ADDR initial_location;
109 /* Number of bytes of program instructions described by this FDE. */
110 CORE_ADDR address_range;
112 /* Instruction sequence. */
113 gdb_byte *instructions;
116 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
118 unsigned char eh_frame_p;
121 struct dwarf2_fde_table
124 struct dwarf2_fde **entries;
127 /* A minimal decoding of DWARF2 compilation units. We only decode
128 what's needed to get to the call frame information. */
132 /* Keep the bfd convenient. */
135 struct objfile *objfile;
137 /* Pointer to the .debug_frame section loaded into memory. */
138 gdb_byte *dwarf_frame_buffer;
140 /* Length of the loaded .debug_frame section. */
141 bfd_size_type dwarf_frame_size;
143 /* Pointer to the .debug_frame section. */
144 asection *dwarf_frame_section;
146 /* Base for DW_EH_PE_datarel encodings. */
149 /* Base for DW_EH_PE_textrel encodings. */
153 static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc);
155 static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum,
158 static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
159 int ptr_len, const gdb_byte *buf,
160 unsigned int *bytes_read_ptr,
161 CORE_ADDR func_base);
164 /* Structure describing a frame state. */
166 struct dwarf2_frame_state
168 /* Each register save state can be described in terms of a CFA slot,
169 another register, or a location expression. */
170 struct dwarf2_frame_state_reg_info
172 struct dwarf2_frame_state_reg *reg;
182 const gdb_byte *cfa_exp;
184 /* Used to implement DW_CFA_remember_state. */
185 struct dwarf2_frame_state_reg_info *prev;
188 /* The PC described by the current frame state. */
191 /* Initial register set from the CIE.
192 Used to implement DW_CFA_restore. */
193 struct dwarf2_frame_state_reg_info initial;
195 /* The information we care about from the CIE. */
198 ULONGEST retaddr_column;
200 /* Flags for known producer quirks. */
202 /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa
203 and DW_CFA_def_cfa_offset takes a factored offset. */
204 int armcc_cfa_offsets_sf;
206 /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
207 the CFA is defined as REG - OFFSET rather than REG + OFFSET. */
208 int armcc_cfa_offsets_reversed;
211 /* Store the length the expression for the CFA in the `cfa_reg' field,
212 which is unused in that case. */
213 #define cfa_exp_len cfa_reg
215 /* Assert that the register set RS is large enough to store gdbarch_num_regs
216 columns. If necessary, enlarge the register set. */
219 dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs,
222 size_t size = sizeof (struct dwarf2_frame_state_reg);
224 if (num_regs <= rs->num_regs)
227 rs->reg = (struct dwarf2_frame_state_reg *)
228 xrealloc (rs->reg, num_regs * size);
230 /* Initialize newly allocated registers. */
231 memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size);
232 rs->num_regs = num_regs;
235 /* Copy the register columns in register set RS into newly allocated
236 memory and return a pointer to this newly created copy. */
238 static struct dwarf2_frame_state_reg *
239 dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs)
241 size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg);
242 struct dwarf2_frame_state_reg *reg;
244 reg = (struct dwarf2_frame_state_reg *) xmalloc (size);
245 memcpy (reg, rs->reg, size);
250 /* Release the memory allocated to register set RS. */
253 dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs)
257 dwarf2_frame_state_free_regs (rs->prev);
264 /* Release the memory allocated to the frame state FS. */
267 dwarf2_frame_state_free (void *p)
269 struct dwarf2_frame_state *fs = p;
271 dwarf2_frame_state_free_regs (fs->initial.prev);
272 dwarf2_frame_state_free_regs (fs->regs.prev);
273 xfree (fs->initial.reg);
274 xfree (fs->regs.reg);
279 /* Helper functions for execute_stack_op. */
282 read_reg (void *baton, int reg)
284 struct frame_info *this_frame = (struct frame_info *) baton;
285 struct gdbarch *gdbarch = get_frame_arch (this_frame);
289 regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
291 buf = alloca (register_size (gdbarch, regnum));
292 get_frame_register (this_frame, regnum, buf);
294 /* Convert the register to an integer. This returns a LONGEST
295 rather than a CORE_ADDR, but unpack_pointer does the same thing
296 under the covers, and this makes more sense for non-pointer
297 registers. Maybe read_reg and the associated interfaces should
298 deal with "struct value" instead of CORE_ADDR. */
299 return unpack_long (register_type (gdbarch, regnum), buf);
303 read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
305 read_memory (addr, buf, len);
309 no_get_frame_base (void *baton, const gdb_byte **start, size_t *length)
311 internal_error (__FILE__, __LINE__,
312 _("Support for DW_OP_fbreg is unimplemented"));
315 /* Helper function for execute_stack_op. */
318 no_get_frame_cfa (void *baton)
320 internal_error (__FILE__, __LINE__,
321 _("Support for DW_OP_call_frame_cfa is unimplemented"));
325 no_get_tls_address (void *baton, CORE_ADDR offset)
327 internal_error (__FILE__, __LINE__,
328 _("Support for DW_OP_GNU_push_tls_address is unimplemented"));
331 /* Execute the required actions for both the DW_CFA_restore and
332 DW_CFA_restore_extended instructions. */
334 dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
335 struct dwarf2_frame_state *fs, int eh_frame_p)
339 gdb_assert (fs->initial.reg);
340 reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
341 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
343 /* Check if this register was explicitly initialized in the
344 CIE initial instructions. If not, default the rule to
346 if (reg < fs->initial.num_regs)
347 fs->regs.reg[reg] = fs->initial.reg[reg];
349 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;
351 if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED)
352 complaint (&symfile_complaints, _("\
353 incomplete CFI data; DW_CFA_restore unspecified\n\
354 register %s (#%d) at %s"),
355 gdbarch_register_name
356 (gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)),
357 gdbarch_dwarf2_reg_to_regnum (gdbarch, reg),
358 paddress (gdbarch, fs->pc));
362 execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
363 struct frame_info *this_frame, CORE_ADDR initial,
364 int initial_in_stack_memory)
366 struct dwarf_expr_context *ctx;
368 struct cleanup *old_chain;
370 ctx = new_dwarf_expr_context ();
371 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
373 ctx->gdbarch = get_frame_arch (this_frame);
374 ctx->addr_size = addr_size;
375 ctx->baton = this_frame;
376 ctx->read_reg = read_reg;
377 ctx->read_mem = read_mem;
378 ctx->get_frame_base = no_get_frame_base;
379 ctx->get_frame_cfa = no_get_frame_cfa;
380 ctx->get_tls_address = no_get_tls_address;
382 dwarf_expr_push (ctx, initial, initial_in_stack_memory);
383 dwarf_expr_eval (ctx, exp, len);
384 result = dwarf_expr_fetch (ctx, 0);
386 if (ctx->location == DWARF_VALUE_REGISTER)
387 result = read_reg (this_frame, result);
388 else if (ctx->location != DWARF_VALUE_MEMORY)
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. */
393 error (_("Not implemented: computing unwound register using explicit value operator"));
396 do_cleanups (old_chain);
403 execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,
404 const gdb_byte *insn_end, struct frame_info *this_frame,
405 struct dwarf2_frame_state *fs)
407 int eh_frame_p = fde->eh_frame_p;
408 CORE_ADDR pc = get_frame_pc (this_frame);
410 struct gdbarch *gdbarch = get_frame_arch (this_frame);
411 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
413 while (insn_ptr < insn_end && fs->pc <= pc)
415 gdb_byte insn = *insn_ptr++;
419 if ((insn & 0xc0) == DW_CFA_advance_loc)
420 fs->pc += (insn & 0x3f) * fs->code_align;
421 else if ((insn & 0xc0) == DW_CFA_offset)
424 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
425 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
426 offset = utmp * fs->data_align;
427 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
428 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
429 fs->regs.reg[reg].loc.offset = offset;
431 else if ((insn & 0xc0) == DW_CFA_restore)
434 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
441 fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
442 fde->cie->addr_size, insn_ptr,
443 &bytes_read, fde->initial_location);
444 /* Apply the objfile offset for relocatable objects. */
445 fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets,
446 SECT_OFF_TEXT (fde->cie->unit->objfile));
447 insn_ptr += bytes_read;
450 case DW_CFA_advance_loc1:
451 utmp = extract_unsigned_integer (insn_ptr, 1, byte_order);
452 fs->pc += utmp * fs->code_align;
455 case DW_CFA_advance_loc2:
456 utmp = extract_unsigned_integer (insn_ptr, 2, byte_order);
457 fs->pc += utmp * fs->code_align;
460 case DW_CFA_advance_loc4:
461 utmp = extract_unsigned_integer (insn_ptr, 4, byte_order);
462 fs->pc += utmp * fs->code_align;
466 case DW_CFA_offset_extended:
467 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
468 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
469 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
470 offset = utmp * fs->data_align;
471 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
472 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
473 fs->regs.reg[reg].loc.offset = offset;
476 case DW_CFA_restore_extended:
477 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
478 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
481 case DW_CFA_undefined:
482 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
483 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
484 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
485 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
488 case DW_CFA_same_value:
489 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
490 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
491 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
492 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE;
495 case DW_CFA_register:
496 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
497 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
498 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
499 utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p);
500 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
501 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
502 fs->regs.reg[reg].loc.reg = utmp;
505 case DW_CFA_remember_state:
507 struct dwarf2_frame_state_reg_info *new_rs;
509 new_rs = XMALLOC (struct dwarf2_frame_state_reg_info);
511 fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs);
512 fs->regs.prev = new_rs;
516 case DW_CFA_restore_state:
518 struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;
522 complaint (&symfile_complaints, _("\
523 bad CFI data; mismatched DW_CFA_restore_state at %s"),
524 paddress (gdbarch, fs->pc));
528 xfree (fs->regs.reg);
536 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
537 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
539 if (fs->armcc_cfa_offsets_sf)
540 utmp *= fs->data_align;
542 fs->regs.cfa_offset = utmp;
543 fs->regs.cfa_how = CFA_REG_OFFSET;
546 case DW_CFA_def_cfa_register:
547 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
548 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch,
551 fs->regs.cfa_how = CFA_REG_OFFSET;
554 case DW_CFA_def_cfa_offset:
555 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
557 if (fs->armcc_cfa_offsets_sf)
558 utmp *= fs->data_align;
560 fs->regs.cfa_offset = utmp;
561 /* cfa_how deliberately not set. */
567 case DW_CFA_def_cfa_expression:
568 insn_ptr = read_uleb128 (insn_ptr, insn_end,
569 &fs->regs.cfa_exp_len);
570 fs->regs.cfa_exp = insn_ptr;
571 fs->regs.cfa_how = CFA_EXP;
572 insn_ptr += fs->regs.cfa_exp_len;
575 case DW_CFA_expression:
576 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
577 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
578 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
579 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
580 fs->regs.reg[reg].loc.exp = insn_ptr;
581 fs->regs.reg[reg].exp_len = utmp;
582 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
586 case DW_CFA_offset_extended_sf:
587 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
588 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
589 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
590 offset *= fs->data_align;
591 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
592 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
593 fs->regs.reg[reg].loc.offset = offset;
596 case DW_CFA_val_offset:
597 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
598 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
599 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
600 offset = utmp * fs->data_align;
601 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
602 fs->regs.reg[reg].loc.offset = offset;
605 case DW_CFA_val_offset_sf:
606 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
607 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
608 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
609 offset *= fs->data_align;
610 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
611 fs->regs.reg[reg].loc.offset = offset;
614 case DW_CFA_val_expression:
615 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
616 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
617 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
618 fs->regs.reg[reg].loc.exp = insn_ptr;
619 fs->regs.reg[reg].exp_len = utmp;
620 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP;
624 case DW_CFA_def_cfa_sf:
625 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
626 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch,
629 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
630 fs->regs.cfa_offset = offset * fs->data_align;
631 fs->regs.cfa_how = CFA_REG_OFFSET;
634 case DW_CFA_def_cfa_offset_sf:
635 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
636 fs->regs.cfa_offset = offset * fs->data_align;
637 /* cfa_how deliberately not set. */
640 case DW_CFA_GNU_window_save:
641 /* This is SPARC-specific code, and contains hard-coded
642 constants for the register numbering scheme used by
643 GCC. Rather than having a architecture-specific
644 operation that's only ever used by a single
645 architecture, we provide the implementation here.
646 Incidentally that's what GCC does too in its
649 int size = register_size (gdbarch, 0);
651 dwarf2_frame_state_alloc_regs (&fs->regs, 32);
652 for (reg = 8; reg < 16; reg++)
654 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
655 fs->regs.reg[reg].loc.reg = reg + 16;
657 for (reg = 16; reg < 32; reg++)
659 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
660 fs->regs.reg[reg].loc.offset = (reg - 16) * size;
665 case DW_CFA_GNU_args_size:
667 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
670 case DW_CFA_GNU_negative_offset_extended:
671 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
672 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
673 insn_ptr = read_uleb128 (insn_ptr, insn_end, &offset);
674 offset *= fs->data_align;
675 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
676 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
677 fs->regs.reg[reg].loc.offset = -offset;
681 internal_error (__FILE__, __LINE__, _("Unknown CFI encountered."));
686 /* Don't allow remember/restore between CIE and FDE programs. */
687 dwarf2_frame_state_free_regs (fs->regs.prev);
688 fs->regs.prev = NULL;
692 /* Architecture-specific operations. */
694 /* Per-architecture data key. */
695 static struct gdbarch_data *dwarf2_frame_data;
697 struct dwarf2_frame_ops
699 /* Pre-initialize the register state REG for register REGNUM. */
700 void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *,
701 struct frame_info *);
703 /* Check whether the THIS_FRAME is a signal trampoline. */
704 int (*signal_frame_p) (struct gdbarch *, struct frame_info *);
706 /* Convert .eh_frame register number to DWARF register number, or
707 adjust .debug_frame register number. */
708 int (*adjust_regnum) (struct gdbarch *, int, int);
711 /* Default architecture-specific register state initialization
715 dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
716 struct dwarf2_frame_state_reg *reg,
717 struct frame_info *this_frame)
719 /* If we have a register that acts as a program counter, mark it as
720 a destination for the return address. If we have a register that
721 serves as the stack pointer, arrange for it to be filled with the
722 call frame address (CFA). The other registers are marked as
725 We copy the return address to the program counter, since many
726 parts in GDB assume that it is possible to get the return address
727 by unwinding the program counter register. However, on ISA's
728 with a dedicated return address register, the CFI usually only
729 contains information to unwind that return address register.
731 The reason we're treating the stack pointer special here is
732 because in many cases GCC doesn't emit CFI for the stack pointer
733 and implicitly assumes that it is equal to the CFA. This makes
734 some sense since the DWARF specification (version 3, draft 8,
737 "Typically, the CFA is defined to be the value of the stack
738 pointer at the call site in the previous frame (which may be
739 different from its value on entry to the current frame)."
741 However, this isn't true for all platforms supported by GCC
742 (e.g. IBM S/390 and zSeries). Those architectures should provide
743 their own architecture-specific initialization function. */
745 if (regnum == gdbarch_pc_regnum (gdbarch))
746 reg->how = DWARF2_FRAME_REG_RA;
747 else if (regnum == gdbarch_sp_regnum (gdbarch))
748 reg->how = DWARF2_FRAME_REG_CFA;
751 /* Return a default for the architecture-specific operations. */
754 dwarf2_frame_init (struct obstack *obstack)
756 struct dwarf2_frame_ops *ops;
758 ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
759 ops->init_reg = dwarf2_frame_default_init_reg;
763 /* Set the architecture-specific register state initialization
764 function for GDBARCH to INIT_REG. */
767 dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
768 void (*init_reg) (struct gdbarch *, int,
769 struct dwarf2_frame_state_reg *,
770 struct frame_info *))
772 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
774 ops->init_reg = init_reg;
777 /* Pre-initialize the register state REG for register REGNUM. */
780 dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
781 struct dwarf2_frame_state_reg *reg,
782 struct frame_info *this_frame)
784 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
786 ops->init_reg (gdbarch, regnum, reg, this_frame);
789 /* Set the architecture-specific signal trampoline recognition
790 function for GDBARCH to SIGNAL_FRAME_P. */
793 dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
794 int (*signal_frame_p) (struct gdbarch *,
795 struct frame_info *))
797 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
799 ops->signal_frame_p = signal_frame_p;
802 /* Query the architecture-specific signal frame recognizer for
806 dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
807 struct frame_info *this_frame)
809 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
811 if (ops->signal_frame_p == NULL)
813 return ops->signal_frame_p (gdbarch, this_frame);
816 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
820 dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
821 int (*adjust_regnum) (struct gdbarch *,
824 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
826 ops->adjust_regnum = adjust_regnum;
829 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
833 dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum, int eh_frame_p)
835 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
837 if (ops->adjust_regnum == NULL)
839 return ops->adjust_regnum (gdbarch, regnum, eh_frame_p);
843 dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
844 struct dwarf2_fde *fde)
848 s = find_pc_symtab (fs->pc);
852 if (producer_is_realview (s->producer))
854 if (fde->cie->version == 1)
855 fs->armcc_cfa_offsets_sf = 1;
857 if (fde->cie->version == 1)
858 fs->armcc_cfa_offsets_reversed = 1;
860 /* The reversed offset problem is present in some compilers
861 using DWARF3, but it was eventually fixed. Check the ARM
862 defined augmentations, which are in the format "armcc" followed
863 by a list of one-character options. The "+" option means
864 this problem is fixed (no quirk needed). If the armcc
865 augmentation is missing, the quirk is needed. */
866 if (fde->cie->version == 3
867 && (strncmp (fde->cie->augmentation, "armcc", 5) != 0
868 || strchr (fde->cie->augmentation + 5, '+') == NULL))
869 fs->armcc_cfa_offsets_reversed = 1;
876 struct dwarf2_frame_cache
878 /* DWARF Call Frame Address. */
881 /* Set if the return address column was marked as undefined. */
882 int undefined_retaddr;
884 /* Saved registers, indexed by GDB register number, not by DWARF
886 struct dwarf2_frame_state_reg *reg;
888 /* Return address register. */
889 struct dwarf2_frame_state_reg retaddr_reg;
891 /* Target address size in bytes. */
895 static struct dwarf2_frame_cache *
896 dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
898 struct cleanup *old_chain;
899 struct gdbarch *gdbarch = get_frame_arch (this_frame);
900 const int num_regs = gdbarch_num_regs (gdbarch)
901 + gdbarch_num_pseudo_regs (gdbarch);
902 struct dwarf2_frame_cache *cache;
903 struct dwarf2_frame_state *fs;
904 struct dwarf2_fde *fde;
909 /* Allocate a new cache. */
910 cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
911 cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
913 /* Allocate and initialize the frame state. */
914 fs = XMALLOC (struct dwarf2_frame_state);
915 memset (fs, 0, sizeof (struct dwarf2_frame_state));
916 old_chain = make_cleanup (dwarf2_frame_state_free, fs);
920 Note that if the next frame is never supposed to return (i.e. a call
921 to abort), the compiler might optimize away the instruction at
922 its return address. As a result the return address will
923 point at some random instruction, and the CFI for that
924 instruction is probably worthless to us. GCC's unwinder solves
925 this problem by substracting 1 from the return address to get an
926 address in the middle of a presumed call instruction (or the
927 instruction in the associated delay slot). This should only be
928 done for "normal" frames and not for resume-type frames (signal
929 handlers, sentinel frames, dummy frames). The function
930 get_frame_address_in_block does just this. It's not clear how
931 reliable the method is though; there is the potential for the
932 register state pre-call being different to that on return. */
933 fs->pc = get_frame_address_in_block (this_frame);
935 /* Find the correct FDE. */
936 fde = dwarf2_frame_find_fde (&fs->pc);
937 gdb_assert (fde != NULL);
939 /* Extract any interesting information from the CIE. */
940 fs->data_align = fde->cie->data_alignment_factor;
941 fs->code_align = fde->cie->code_alignment_factor;
942 fs->retaddr_column = fde->cie->return_address_register;
943 cache->addr_size = fde->cie->addr_size;
945 /* Check for "quirks" - known bugs in producers. */
946 dwarf2_frame_find_quirks (fs, fde);
948 /* First decode all the insns in the CIE. */
949 execute_cfa_program (fde, fde->cie->initial_instructions,
950 fde->cie->end, this_frame, fs);
952 /* Save the initialized register set. */
953 fs->initial = fs->regs;
954 fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs);
956 /* Then decode the insns in the FDE up to our target PC. */
957 execute_cfa_program (fde, fde->instructions, fde->end, this_frame, fs);
959 /* Calculate the CFA. */
960 switch (fs->regs.cfa_how)
963 cache->cfa = read_reg (this_frame, fs->regs.cfa_reg);
964 if (fs->armcc_cfa_offsets_reversed)
965 cache->cfa -= fs->regs.cfa_offset;
967 cache->cfa += fs->regs.cfa_offset;
972 execute_stack_op (fs->regs.cfa_exp, fs->regs.cfa_exp_len,
973 cache->addr_size, this_frame, 0, 0);
977 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
980 /* Initialize the register state. */
984 for (regnum = 0; regnum < num_regs; regnum++)
985 dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame);
988 /* Go through the DWARF2 CFI generated table and save its register
989 location information in the cache. Note that we don't skip the
990 return address column; it's perfectly all right for it to
991 correspond to a real register. If it doesn't correspond to a
992 real register, or if we shouldn't treat it as such,
993 gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside
994 the range [0, gdbarch_num_regs). */
996 int column; /* CFI speak for "register number". */
998 for (column = 0; column < fs->regs.num_regs; column++)
1000 /* Use the GDB register number as the destination index. */
1001 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, column);
1003 /* If there's no corresponding GDB register, ignore it. */
1004 if (regnum < 0 || regnum >= num_regs)
1007 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1008 of all debug info registers. If it doesn't, complain (but
1009 not too loudly). It turns out that GCC assumes that an
1010 unspecified register implies "same value" when CFI (draft
1011 7) specifies nothing at all. Such a register could equally
1012 be interpreted as "undefined". Also note that this check
1013 isn't sufficient; it only checks that all registers in the
1014 range [0 .. max column] are specified, and won't detect
1015 problems when a debug info register falls outside of the
1016 table. We need a way of iterating through all the valid
1017 DWARF2 register numbers. */
1018 if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
1020 if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED)
1021 complaint (&symfile_complaints, _("\
1022 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1023 gdbarch_register_name (gdbarch, regnum),
1024 paddress (gdbarch, fs->pc));
1027 cache->reg[regnum] = fs->regs.reg[column];
1031 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1032 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1036 for (regnum = 0; regnum < num_regs; regnum++)
1038 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
1039 || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
1041 struct dwarf2_frame_state_reg *retaddr_reg =
1042 &fs->regs.reg[fs->retaddr_column];
1044 /* It seems rather bizarre to specify an "empty" column as
1045 the return adress column. However, this is exactly
1046 what GCC does on some targets. It turns out that GCC
1047 assumes that the return address can be found in the
1048 register corresponding to the return address column.
1049 Incidentally, that's how we should treat a return
1050 address column specifying "same value" too. */
1051 if (fs->retaddr_column < fs->regs.num_regs
1052 && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
1053 && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
1055 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1056 cache->reg[regnum] = *retaddr_reg;
1058 cache->retaddr_reg = *retaddr_reg;
1062 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1064 cache->reg[regnum].loc.reg = fs->retaddr_column;
1065 cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
1069 cache->retaddr_reg.loc.reg = fs->retaddr_column;
1070 cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG;
1077 if (fs->retaddr_column < fs->regs.num_regs
1078 && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
1079 cache->undefined_retaddr = 1;
1081 do_cleanups (old_chain);
1083 *this_cache = cache;
1088 dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
1089 struct frame_id *this_id)
1091 struct dwarf2_frame_cache *cache =
1092 dwarf2_frame_cache (this_frame, this_cache);
1094 if (cache->undefined_retaddr)
1097 (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
1100 static struct value *
1101 dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache,
1104 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1105 struct dwarf2_frame_cache *cache =
1106 dwarf2_frame_cache (this_frame, this_cache);
1110 switch (cache->reg[regnum].how)
1112 case DWARF2_FRAME_REG_UNDEFINED:
1113 /* If CFI explicitly specified that the value isn't defined,
1114 mark it as optimized away; the value isn't available. */
1115 return frame_unwind_got_optimized (this_frame, regnum);
1117 case DWARF2_FRAME_REG_SAVED_OFFSET:
1118 addr = cache->cfa + cache->reg[regnum].loc.offset;
1119 return frame_unwind_got_memory (this_frame, regnum, addr);
1121 case DWARF2_FRAME_REG_SAVED_REG:
1123 = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg);
1124 return frame_unwind_got_register (this_frame, regnum, realnum);
1126 case DWARF2_FRAME_REG_SAVED_EXP:
1127 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1128 cache->reg[regnum].exp_len,
1129 cache->addr_size, this_frame, cache->cfa, 1);
1130 return frame_unwind_got_memory (this_frame, regnum, addr);
1132 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET:
1133 addr = cache->cfa + cache->reg[regnum].loc.offset;
1134 return frame_unwind_got_constant (this_frame, regnum, addr);
1136 case DWARF2_FRAME_REG_SAVED_VAL_EXP:
1137 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1138 cache->reg[regnum].exp_len,
1139 cache->addr_size, this_frame, cache->cfa, 1);
1140 return frame_unwind_got_constant (this_frame, regnum, addr);
1142 case DWARF2_FRAME_REG_UNSPECIFIED:
1143 /* GCC, in its infinite wisdom decided to not provide unwind
1144 information for registers that are "same value". Since
1145 DWARF2 (3 draft 7) doesn't define such behavior, said
1146 registers are actually undefined (which is different to CFI
1147 "undefined"). Code above issues a complaint about this.
1148 Here just fudge the books, assume GCC, and that the value is
1149 more inner on the stack. */
1150 return frame_unwind_got_register (this_frame, regnum, regnum);
1152 case DWARF2_FRAME_REG_SAME_VALUE:
1153 return frame_unwind_got_register (this_frame, regnum, regnum);
1155 case DWARF2_FRAME_REG_CFA:
1156 return frame_unwind_got_address (this_frame, regnum, cache->cfa);
1158 case DWARF2_FRAME_REG_CFA_OFFSET:
1159 addr = cache->cfa + cache->reg[regnum].loc.offset;
1160 return frame_unwind_got_address (this_frame, regnum, addr);
1162 case DWARF2_FRAME_REG_RA_OFFSET:
1163 addr = cache->reg[regnum].loc.offset;
1164 regnum = gdbarch_dwarf2_reg_to_regnum
1165 (gdbarch, cache->retaddr_reg.loc.reg);
1166 addr += get_frame_register_unsigned (this_frame, regnum);
1167 return frame_unwind_got_address (this_frame, regnum, addr);
1169 case DWARF2_FRAME_REG_FN:
1170 return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum);
1173 internal_error (__FILE__, __LINE__, _("Unknown register rule."));
1178 dwarf2_frame_sniffer (const struct frame_unwind *self,
1179 struct frame_info *this_frame, void **this_cache)
1181 /* Grab an address that is guarenteed to reside somewhere within the
1182 function. get_frame_pc(), with a no-return next function, can
1183 end up returning something past the end of this function's body.
1184 If the frame we're sniffing for is a signal frame whose start
1185 address is placed on the stack by the OS, its FDE must
1186 extend one byte before its start address or we could potentially
1187 select the FDE of the previous function. */
1188 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1189 struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr);
1194 /* On some targets, signal trampolines may have unwind information.
1195 We need to recognize them so that we set the frame type
1198 if (fde->cie->signal_frame
1199 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame),
1201 return self->type == SIGTRAMP_FRAME;
1203 return self->type != SIGTRAMP_FRAME;
1206 static const struct frame_unwind dwarf2_frame_unwind =
1209 dwarf2_frame_this_id,
1210 dwarf2_frame_prev_register,
1212 dwarf2_frame_sniffer
1215 static const struct frame_unwind dwarf2_signal_frame_unwind =
1218 dwarf2_frame_this_id,
1219 dwarf2_frame_prev_register,
1221 dwarf2_frame_sniffer
1224 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1227 dwarf2_append_unwinders (struct gdbarch *gdbarch)
1229 frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind);
1230 frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind);
1234 /* There is no explicitly defined relationship between the CFA and the
1235 location of frame's local variables and arguments/parameters.
1236 Therefore, frame base methods on this page should probably only be
1237 used as a last resort, just to avoid printing total garbage as a
1238 response to the "info frame" command. */
1241 dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache)
1243 struct dwarf2_frame_cache *cache =
1244 dwarf2_frame_cache (this_frame, this_cache);
1249 static const struct frame_base dwarf2_frame_base =
1251 &dwarf2_frame_unwind,
1252 dwarf2_frame_base_address,
1253 dwarf2_frame_base_address,
1254 dwarf2_frame_base_address
1257 const struct frame_base *
1258 dwarf2_frame_base_sniffer (struct frame_info *this_frame)
1260 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1262 if (dwarf2_frame_find_fde (&block_addr))
1263 return &dwarf2_frame_base;
1268 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1269 the DWARF unwinder. This is used to implement
1270 DW_OP_call_frame_cfa. */
1273 dwarf2_frame_cfa (struct frame_info *this_frame)
1275 while (get_frame_type (this_frame) == INLINE_FRAME)
1276 this_frame = get_prev_frame (this_frame);
1277 /* This restriction could be lifted if other unwinders are known to
1278 compute the frame base in a way compatible with the DWARF
1280 if (! frame_unwinder_is (this_frame, &dwarf2_frame_unwind))
1281 error (_("can't compute CFA for this frame"));
1282 return get_frame_base (this_frame);
1285 const struct objfile_data *dwarf2_frame_objfile_data;
1288 read_1_byte (bfd *abfd, gdb_byte *buf)
1290 return bfd_get_8 (abfd, buf);
1294 read_4_bytes (bfd *abfd, gdb_byte *buf)
1296 return bfd_get_32 (abfd, buf);
1300 read_8_bytes (bfd *abfd, gdb_byte *buf)
1302 return bfd_get_64 (abfd, buf);
1306 read_unsigned_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1309 unsigned int num_read;
1319 byte = bfd_get_8 (abfd, (bfd_byte *) buf);
1322 result |= ((byte & 0x7f) << shift);
1325 while (byte & 0x80);
1327 *bytes_read_ptr = num_read;
1333 read_signed_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1337 unsigned int num_read;
1346 byte = bfd_get_8 (abfd, (bfd_byte *) buf);
1349 result |= ((byte & 0x7f) << shift);
1352 while (byte & 0x80);
1354 if (shift < 8 * sizeof (result) && (byte & 0x40))
1355 result |= -(((LONGEST)1) << shift);
1357 *bytes_read_ptr = num_read;
1363 read_initial_length (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1367 result = bfd_get_32 (abfd, buf);
1368 if (result == 0xffffffff)
1370 result = bfd_get_64 (abfd, buf + 4);
1371 *bytes_read_ptr = 12;
1374 *bytes_read_ptr = 4;
1380 /* Pointer encoding helper functions. */
1382 /* GCC supports exception handling based on DWARF2 CFI. However, for
1383 technical reasons, it encodes addresses in its FDE's in a different
1384 way. Several "pointer encodings" are supported. The encoding
1385 that's used for a particular FDE is determined by the 'R'
1386 augmentation in the associated CIE. The argument of this
1387 augmentation is a single byte.
1389 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1390 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1391 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1392 address should be interpreted (absolute, relative to the current
1393 position in the FDE, ...). Bit 7, indicates that the address
1394 should be dereferenced. */
1397 encoding_for_size (unsigned int size)
1402 return DW_EH_PE_udata2;
1404 return DW_EH_PE_udata4;
1406 return DW_EH_PE_udata8;
1408 internal_error (__FILE__, __LINE__, _("Unsupported address size"));
1413 read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
1414 int ptr_len, const gdb_byte *buf,
1415 unsigned int *bytes_read_ptr,
1416 CORE_ADDR func_base)
1421 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1423 if (encoding & DW_EH_PE_indirect)
1424 internal_error (__FILE__, __LINE__,
1425 _("Unsupported encoding: DW_EH_PE_indirect"));
1427 *bytes_read_ptr = 0;
1429 switch (encoding & 0x70)
1431 case DW_EH_PE_absptr:
1434 case DW_EH_PE_pcrel:
1435 base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section);
1436 base += (buf - unit->dwarf_frame_buffer);
1438 case DW_EH_PE_datarel:
1441 case DW_EH_PE_textrel:
1444 case DW_EH_PE_funcrel:
1447 case DW_EH_PE_aligned:
1449 offset = buf - unit->dwarf_frame_buffer;
1450 if ((offset % ptr_len) != 0)
1452 *bytes_read_ptr = ptr_len - (offset % ptr_len);
1453 buf += *bytes_read_ptr;
1457 internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding"));
1460 if ((encoding & 0x07) == 0x00)
1462 encoding |= encoding_for_size (ptr_len);
1463 if (bfd_get_sign_extend_vma (unit->abfd))
1464 encoding |= DW_EH_PE_signed;
1467 switch (encoding & 0x0f)
1469 case DW_EH_PE_uleb128:
1472 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1474 *bytes_read_ptr += read_uleb128 (buf, end_buf, &value) - buf;
1475 return base + value;
1477 case DW_EH_PE_udata2:
1478 *bytes_read_ptr += 2;
1479 return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf));
1480 case DW_EH_PE_udata4:
1481 *bytes_read_ptr += 4;
1482 return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf));
1483 case DW_EH_PE_udata8:
1484 *bytes_read_ptr += 8;
1485 return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf));
1486 case DW_EH_PE_sleb128:
1489 const 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 /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
1528 bsearch be non-NULL. */
1529 if (cie_table->entries == NULL)
1531 gdb_assert (cie_table->num_entries == 0);
1535 p_cie = bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries,
1536 sizeof (cie_table->entries[0]), bsearch_cie_cmp);
1542 /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1544 add_cie (struct dwarf2_cie_table *cie_table, struct dwarf2_cie *cie)
1546 const int n = cie_table->num_entries;
1549 || cie_table->entries[n - 1]->cie_pointer < cie->cie_pointer);
1551 cie_table->entries =
1552 xrealloc (cie_table->entries, (n + 1) * sizeof (cie_table->entries[0]));
1553 cie_table->entries[n] = cie;
1554 cie_table->num_entries = n + 1;
1558 bsearch_fde_cmp (const void *key, const void *element)
1560 CORE_ADDR seek_pc = *(CORE_ADDR *) key;
1561 struct dwarf2_fde *fde = *(struct dwarf2_fde **) element;
1563 if (seek_pc < fde->initial_location)
1565 if (seek_pc < fde->initial_location + fde->address_range)
1570 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1571 inital location associated with it into *PC. */
1573 static struct dwarf2_fde *
1574 dwarf2_frame_find_fde (CORE_ADDR *pc)
1576 struct objfile *objfile;
1578 ALL_OBJFILES (objfile)
1580 struct dwarf2_fde_table *fde_table;
1581 struct dwarf2_fde **p_fde;
1585 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1586 if (fde_table == NULL)
1588 dwarf2_build_frame_info (objfile);
1589 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1591 gdb_assert (fde_table != NULL);
1593 if (fde_table->num_entries == 0)
1596 gdb_assert (objfile->section_offsets);
1597 offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
1599 gdb_assert (fde_table->num_entries > 0);
1600 if (*pc < offset + fde_table->entries[0]->initial_location)
1603 seek_pc = *pc - offset;
1604 p_fde = bsearch (&seek_pc, fde_table->entries, fde_table->num_entries,
1605 sizeof (fde_table->entries[0]), bsearch_fde_cmp);
1608 *pc = (*p_fde)->initial_location + offset;
1615 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1617 add_fde (struct dwarf2_fde_table *fde_table, struct dwarf2_fde *fde)
1619 if (fde->address_range == 0)
1620 /* Discard useless FDEs. */
1623 fde_table->num_entries += 1;
1624 fde_table->entries =
1625 xrealloc (fde_table->entries,
1626 fde_table->num_entries * sizeof (fde_table->entries[0]));
1627 fde_table->entries[fde_table->num_entries - 1] = fde;
1630 #ifdef CC_HAS_LONG_LONG
1631 #define DW64_CIE_ID 0xffffffffffffffffULL
1633 #define DW64_CIE_ID ~0
1636 static gdb_byte *decode_frame_entry (struct comp_unit *unit, gdb_byte *start,
1638 struct dwarf2_cie_table *cie_table,
1639 struct dwarf2_fde_table *fde_table);
1641 /* Decode the next CIE or FDE. Return NULL if invalid input, otherwise
1642 the next byte to be processed. */
1644 decode_frame_entry_1 (struct comp_unit *unit, gdb_byte *start, int eh_frame_p,
1645 struct dwarf2_cie_table *cie_table,
1646 struct dwarf2_fde_table *fde_table)
1648 struct gdbarch *gdbarch = get_objfile_arch (unit->objfile);
1649 gdb_byte *buf, *end;
1651 unsigned int bytes_read;
1654 ULONGEST cie_pointer;
1657 length = read_initial_length (unit->abfd, buf, &bytes_read);
1661 /* Are we still within the section? */
1662 if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
1668 /* Distinguish between 32 and 64-bit encoded frame info. */
1669 dwarf64_p = (bytes_read == 12);
1671 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1675 cie_id = DW64_CIE_ID;
1681 cie_pointer = read_8_bytes (unit->abfd, buf);
1686 cie_pointer = read_4_bytes (unit->abfd, buf);
1690 if (cie_pointer == cie_id)
1692 /* This is a CIE. */
1693 struct dwarf2_cie *cie;
1695 unsigned int cie_version;
1697 /* Record the offset into the .debug_frame section of this CIE. */
1698 cie_pointer = start - unit->dwarf_frame_buffer;
1700 /* Check whether we've already read it. */
1701 if (find_cie (cie_table, cie_pointer))
1704 cie = (struct dwarf2_cie *)
1705 obstack_alloc (&unit->objfile->objfile_obstack,
1706 sizeof (struct dwarf2_cie));
1707 cie->initial_instructions = NULL;
1708 cie->cie_pointer = cie_pointer;
1710 /* The encoding for FDE's in a normal .debug_frame section
1711 depends on the target address size. */
1712 cie->encoding = DW_EH_PE_absptr;
1714 /* The target address size. For .eh_frame FDEs this is considered
1715 equal to the size of a target pointer. For .dwarf_frame FDEs,
1716 this is supposed to be the target address size from the associated
1717 CU header. FIXME: We do not have a good way to determine the
1718 latter. Always use the target pointer size for now. */
1719 cie->addr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1721 /* We'll determine the final value later, but we need to
1722 initialize it conservatively. */
1723 cie->signal_frame = 0;
1725 /* Check version number. */
1726 cie_version = read_1_byte (unit->abfd, buf);
1727 if (cie_version != 1 && cie_version != 3 && cie_version != 4)
1729 cie->version = cie_version;
1732 /* Interpret the interesting bits of the augmentation. */
1733 cie->augmentation = augmentation = (char *) buf;
1734 buf += (strlen (augmentation) + 1);
1736 /* Ignore armcc augmentations. We only use them for quirks,
1737 and that doesn't happen until later. */
1738 if (strncmp (augmentation, "armcc", 5) == 0)
1739 augmentation += strlen (augmentation);
1741 /* The GCC 2.x "eh" augmentation has a pointer immediately
1742 following the augmentation string, so it must be handled
1744 if (augmentation[0] == 'e' && augmentation[1] == 'h')
1747 buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1751 if (cie->version >= 4)
1753 /* FIXME: check that this is the same as from the CU header. */
1754 cie->addr_size = read_1_byte (unit->abfd, buf);
1756 cie->segment_size = read_1_byte (unit->abfd, buf);
1761 cie->addr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1762 cie->segment_size = 0;
1765 cie->code_alignment_factor =
1766 read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
1769 cie->data_alignment_factor =
1770 read_signed_leb128 (unit->abfd, buf, &bytes_read);
1773 if (cie_version == 1)
1775 cie->return_address_register = read_1_byte (unit->abfd, buf);
1779 cie->return_address_register = read_unsigned_leb128 (unit->abfd, buf,
1781 cie->return_address_register
1782 = dwarf2_frame_adjust_regnum (gdbarch,
1783 cie->return_address_register,
1788 cie->saw_z_augmentation = (*augmentation == 'z');
1789 if (cie->saw_z_augmentation)
1793 length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
1797 cie->initial_instructions = buf + length;
1801 while (*augmentation)
1803 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1804 if (*augmentation == 'L')
1811 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1812 else if (*augmentation == 'R')
1814 cie->encoding = *buf++;
1818 /* "P" indicates a personality routine in the CIE augmentation. */
1819 else if (*augmentation == 'P')
1821 /* Skip. Avoid indirection since we throw away the result. */
1822 gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect;
1823 read_encoded_value (unit, encoding, cie->addr_size,
1824 buf, &bytes_read, 0);
1829 /* "S" indicates a signal frame, such that the return
1830 address must not be decremented to locate the call frame
1831 info for the previous frame; it might even be the first
1832 instruction of a function, so decrementing it would take
1833 us to a different function. */
1834 else if (*augmentation == 'S')
1836 cie->signal_frame = 1;
1840 /* Otherwise we have an unknown augmentation. Assume that either
1841 there is no augmentation data, or we saw a 'z' prefix. */
1844 if (cie->initial_instructions)
1845 buf = cie->initial_instructions;
1850 cie->initial_instructions = buf;
1854 add_cie (cie_table, cie);
1858 /* This is a FDE. */
1859 struct dwarf2_fde *fde;
1861 /* In an .eh_frame section, the CIE pointer is the delta between the
1862 address within the FDE where the CIE pointer is stored and the
1863 address of the CIE. Convert it to an offset into the .eh_frame
1867 cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
1868 cie_pointer -= (dwarf64_p ? 8 : 4);
1871 /* In either case, validate the result is still within the section. */
1872 if (cie_pointer >= unit->dwarf_frame_size)
1875 fde = (struct dwarf2_fde *)
1876 obstack_alloc (&unit->objfile->objfile_obstack,
1877 sizeof (struct dwarf2_fde));
1878 fde->cie = find_cie (cie_table, cie_pointer);
1879 if (fde->cie == NULL)
1881 decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer,
1882 eh_frame_p, cie_table, fde_table);
1883 fde->cie = find_cie (cie_table, cie_pointer);
1886 gdb_assert (fde->cie != NULL);
1888 fde->initial_location =
1889 read_encoded_value (unit, fde->cie->encoding, fde->cie->addr_size,
1890 buf, &bytes_read, 0);
1893 fde->address_range =
1894 read_encoded_value (unit, fde->cie->encoding & 0x0f,
1895 fde->cie->addr_size, buf, &bytes_read, 0);
1898 /* A 'z' augmentation in the CIE implies the presence of an
1899 augmentation field in the FDE as well. The only thing known
1900 to be in here at present is the LSDA entry for EH. So we
1901 can skip the whole thing. */
1902 if (fde->cie->saw_z_augmentation)
1906 length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
1907 buf += bytes_read + length;
1912 fde->instructions = buf;
1915 fde->eh_frame_p = eh_frame_p;
1917 add_fde (fde_table, fde);
1923 /* Read a CIE or FDE in BUF and decode it. */
1925 decode_frame_entry (struct comp_unit *unit, gdb_byte *start, int eh_frame_p,
1926 struct dwarf2_cie_table *cie_table,
1927 struct dwarf2_fde_table *fde_table)
1929 enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
1931 ptrdiff_t start_offset;
1935 ret = decode_frame_entry_1 (unit, start, eh_frame_p,
1936 cie_table, fde_table);
1940 /* We have corrupt input data of some form. */
1942 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
1943 and mismatches wrt padding and alignment of debug sections. */
1944 /* Note that there is no requirement in the standard for any
1945 alignment at all in the frame unwind sections. Testing for
1946 alignment before trying to interpret data would be incorrect.
1948 However, GCC traditionally arranged for frame sections to be
1949 sized such that the FDE length and CIE fields happen to be
1950 aligned (in theory, for performance). This, unfortunately,
1951 was done with .align directives, which had the side effect of
1952 forcing the section to be aligned by the linker.
1954 This becomes a problem when you have some other producer that
1955 creates frame sections that are not as strictly aligned. That
1956 produces a hole in the frame info that gets filled by the
1959 The GCC behaviour is arguably a bug, but it's effectively now
1960 part of the ABI, so we're now stuck with it, at least at the
1961 object file level. A smart linker may decide, in the process
1962 of compressing duplicate CIE information, that it can rewrite
1963 the entire output section without this extra padding. */
1965 start_offset = start - unit->dwarf_frame_buffer;
1966 if (workaround < ALIGN4 && (start_offset & 3) != 0)
1968 start += 4 - (start_offset & 3);
1969 workaround = ALIGN4;
1972 if (workaround < ALIGN8 && (start_offset & 7) != 0)
1974 start += 8 - (start_offset & 7);
1975 workaround = ALIGN8;
1979 /* Nothing left to try. Arrange to return as if we've consumed
1980 the entire input section. Hopefully we'll get valid info from
1981 the other of .debug_frame/.eh_frame. */
1983 ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
1993 complaint (&symfile_complaints,
1994 _("Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
1995 unit->dwarf_frame_section->owner->filename,
1996 unit->dwarf_frame_section->name);
2000 complaint (&symfile_complaints,
2001 _("Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
2002 unit->dwarf_frame_section->owner->filename,
2003 unit->dwarf_frame_section->name);
2007 complaint (&symfile_complaints,
2008 _("Corrupt data in %s:%s"),
2009 unit->dwarf_frame_section->owner->filename,
2010 unit->dwarf_frame_section->name);
2018 /* Imported from dwarf2read.c. */
2019 extern void dwarf2_get_section_info (struct objfile *, const char *, asection **,
2020 gdb_byte **, bfd_size_type *);
2023 qsort_fde_cmp (const void *a, const void *b)
2025 struct dwarf2_fde *aa = *(struct dwarf2_fde **)a;
2026 struct dwarf2_fde *bb = *(struct dwarf2_fde **)b;
2028 if (aa->initial_location == bb->initial_location)
2030 if (aa->address_range != bb->address_range
2031 && aa->eh_frame_p == 0 && bb->eh_frame_p == 0)
2032 /* Linker bug, e.g. gold/10400.
2033 Work around it by keeping stable sort order. */
2034 return (a < b) ? -1 : 1;
2036 /* Put eh_frame entries after debug_frame ones. */
2037 return aa->eh_frame_p - bb->eh_frame_p;
2040 return (aa->initial_location < bb->initial_location) ? -1 : 1;
2044 dwarf2_build_frame_info (struct objfile *objfile)
2046 struct comp_unit *unit;
2047 gdb_byte *frame_ptr;
2048 struct dwarf2_cie_table cie_table;
2049 struct dwarf2_fde_table fde_table;
2050 struct dwarf2_fde_table *fde_table2;
2052 cie_table.num_entries = 0;
2053 cie_table.entries = NULL;
2055 fde_table.num_entries = 0;
2056 fde_table.entries = NULL;
2058 /* Build a minimal decoding of the DWARF2 compilation unit. */
2059 unit = (struct comp_unit *) obstack_alloc (&objfile->objfile_obstack,
2060 sizeof (struct comp_unit));
2061 unit->abfd = objfile->obfd;
2062 unit->objfile = objfile;
2066 dwarf2_get_section_info (objfile, ".eh_frame",
2067 &unit->dwarf_frame_section,
2068 &unit->dwarf_frame_buffer,
2069 &unit->dwarf_frame_size);
2070 if (unit->dwarf_frame_size)
2072 asection *got, *txt;
2074 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2075 that is used for the i386/amd64 target, which currently is
2076 the only target in GCC that supports/uses the
2077 DW_EH_PE_datarel encoding. */
2078 got = bfd_get_section_by_name (unit->abfd, ".got");
2080 unit->dbase = got->vma;
2082 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2084 txt = bfd_get_section_by_name (unit->abfd, ".text");
2086 unit->tbase = txt->vma;
2088 frame_ptr = unit->dwarf_frame_buffer;
2089 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2090 frame_ptr = decode_frame_entry (unit, frame_ptr, 1,
2091 &cie_table, &fde_table);
2093 if (cie_table.num_entries != 0)
2095 /* Reinit cie_table: debug_frame has different CIEs. */
2096 xfree (cie_table.entries);
2097 cie_table.num_entries = 0;
2098 cie_table.entries = NULL;
2102 dwarf2_get_section_info (objfile, ".debug_frame",
2103 &unit->dwarf_frame_section,
2104 &unit->dwarf_frame_buffer,
2105 &unit->dwarf_frame_size);
2106 if (unit->dwarf_frame_size)
2108 frame_ptr = unit->dwarf_frame_buffer;
2109 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2110 frame_ptr = decode_frame_entry (unit, frame_ptr, 0,
2111 &cie_table, &fde_table);
2114 /* Discard the cie_table, it is no longer needed. */
2115 if (cie_table.num_entries != 0)
2117 xfree (cie_table.entries);
2118 cie_table.entries = NULL; /* Paranoia. */
2119 cie_table.num_entries = 0; /* Paranoia. */
2122 /* Copy fde_table to obstack: it is needed at runtime. */
2123 fde_table2 = (struct dwarf2_fde_table *)
2124 obstack_alloc (&objfile->objfile_obstack, sizeof (*fde_table2));
2126 if (fde_table.num_entries == 0)
2128 fde_table2->entries = NULL;
2129 fde_table2->num_entries = 0;
2133 struct dwarf2_fde *fde_prev = NULL;
2134 struct dwarf2_fde *first_non_zero_fde = NULL;
2137 /* Prepare FDE table for lookups. */
2138 qsort (fde_table.entries, fde_table.num_entries,
2139 sizeof (fde_table.entries[0]), qsort_fde_cmp);
2141 /* Check for leftovers from --gc-sections. The GNU linker sets
2142 the relevant symbols to zero, but doesn't zero the FDE *end*
2143 ranges because there's no relocation there. It's (offset,
2144 length), not (start, end). On targets where address zero is
2145 just another valid address this can be a problem, since the
2146 FDEs appear to be non-empty in the output --- we could pick
2147 out the wrong FDE. To work around this, when overlaps are
2148 detected, we prefer FDEs that do not start at zero.
2150 Start by finding the first FDE with non-zero start. Below
2151 we'll discard all FDEs that start at zero and overlap this
2153 for (i = 0; i < fde_table.num_entries; i++)
2155 struct dwarf2_fde *fde = fde_table.entries[i];
2157 if (fde->initial_location != 0)
2159 first_non_zero_fde = fde;
2164 /* Since we'll be doing bsearch, squeeze out identical (except
2165 for eh_frame_p) fde entries so bsearch result is predictable.
2166 Also discard leftovers from --gc-sections. */
2167 fde_table2->num_entries = 0;
2168 for (i = 0; i < fde_table.num_entries; i++)
2170 struct dwarf2_fde *fde = fde_table.entries[i];
2172 if (fde->initial_location == 0
2173 && first_non_zero_fde != NULL
2174 && (first_non_zero_fde->initial_location
2175 < fde->initial_location + fde->address_range))
2178 if (fde_prev != NULL
2179 && fde_prev->initial_location == fde->initial_location)
2182 obstack_grow (&objfile->objfile_obstack, &fde_table.entries[i],
2183 sizeof (fde_table.entries[0]));
2184 ++fde_table2->num_entries;
2187 fde_table2->entries = obstack_finish (&objfile->objfile_obstack);
2189 /* Discard the original fde_table. */
2190 xfree (fde_table.entries);
2193 set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2);
2196 /* Provide a prototype to silence -Wmissing-prototypes. */
2197 void _initialize_dwarf2_frame (void);
2200 _initialize_dwarf2_frame (void)
2202 dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
2203 dwarf2_frame_objfile_data = register_objfile_data ();