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"));
313 no_get_tls_address (void *baton
, CORE_ADDR offset
)
315 internal_error (__FILE__
, __LINE__
,
316 _("Support for DW_OP_GNU_push_tls_address is unimplemented"));
319 /* Execute the required actions for both the DW_CFA_restore and
320 DW_CFA_restore_extended instructions. */
322 dwarf2_restore_rule (struct gdbarch
*gdbarch
, ULONGEST reg_num
,
323 struct dwarf2_frame_state
*fs
, int eh_frame_p
)
327 gdb_assert (fs
->initial
.reg
);
328 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg_num
, eh_frame_p
);
329 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
331 /* Check if this register was explicitly initialized in the
332 CIE initial instructions. If not, default the rule to
334 if (reg
< fs
->initial
.num_regs
)
335 fs
->regs
.reg
[reg
] = fs
->initial
.reg
[reg
];
337 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNSPECIFIED
;
339 if (fs
->regs
.reg
[reg
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
340 complaint (&symfile_complaints
, _("\
341 incomplete CFI data; DW_CFA_restore unspecified\n\
342 register %s (#%d) at %s"),
343 gdbarch_register_name
344 (gdbarch
, gdbarch_dwarf2_reg_to_regnum (gdbarch
, reg
)),
345 gdbarch_dwarf2_reg_to_regnum (gdbarch
, reg
),
346 paddress (gdbarch
, fs
->pc
));
350 execute_stack_op (gdb_byte
*exp
, ULONGEST len
, int addr_size
,
351 struct frame_info
*this_frame
, CORE_ADDR initial
)
353 struct dwarf_expr_context
*ctx
;
356 ctx
= new_dwarf_expr_context ();
357 ctx
->gdbarch
= get_frame_arch (this_frame
);
358 ctx
->addr_size
= addr_size
;
359 ctx
->baton
= this_frame
;
360 ctx
->read_reg
= read_reg
;
361 ctx
->read_mem
= read_mem
;
362 ctx
->get_frame_base
= no_get_frame_base
;
363 ctx
->get_tls_address
= no_get_tls_address
;
365 dwarf_expr_push (ctx
, initial
);
366 dwarf_expr_eval (ctx
, exp
, len
);
367 result
= dwarf_expr_fetch (ctx
, 0);
370 result
= read_reg (this_frame
, result
);
372 free_dwarf_expr_context (ctx
);
379 execute_cfa_program (struct dwarf2_fde
*fde
, gdb_byte
*insn_ptr
,
380 gdb_byte
*insn_end
, struct frame_info
*this_frame
,
381 struct dwarf2_frame_state
*fs
)
383 int eh_frame_p
= fde
->eh_frame_p
;
384 CORE_ADDR pc
= get_frame_pc (this_frame
);
386 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
387 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
389 while (insn_ptr
< insn_end
&& fs
->pc
<= pc
)
391 gdb_byte insn
= *insn_ptr
++;
395 if ((insn
& 0xc0) == DW_CFA_advance_loc
)
396 fs
->pc
+= (insn
& 0x3f) * fs
->code_align
;
397 else if ((insn
& 0xc0) == DW_CFA_offset
)
400 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
401 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
402 offset
= utmp
* fs
->data_align
;
403 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
404 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
405 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
407 else if ((insn
& 0xc0) == DW_CFA_restore
)
410 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
417 fs
->pc
= read_encoded_value (fde
->cie
->unit
, fde
->cie
->encoding
,
418 fde
->cie
->addr_size
, insn_ptr
,
419 &bytes_read
, fde
->initial_location
);
420 /* Apply the objfile offset for relocatable objects. */
421 fs
->pc
+= ANOFFSET (fde
->cie
->unit
->objfile
->section_offsets
,
422 SECT_OFF_TEXT (fde
->cie
->unit
->objfile
));
423 insn_ptr
+= bytes_read
;
426 case DW_CFA_advance_loc1
:
427 utmp
= extract_unsigned_integer (insn_ptr
, 1, byte_order
);
428 fs
->pc
+= utmp
* fs
->code_align
;
431 case DW_CFA_advance_loc2
:
432 utmp
= extract_unsigned_integer (insn_ptr
, 2, byte_order
);
433 fs
->pc
+= utmp
* fs
->code_align
;
436 case DW_CFA_advance_loc4
:
437 utmp
= extract_unsigned_integer (insn_ptr
, 4, byte_order
);
438 fs
->pc
+= utmp
* fs
->code_align
;
442 case DW_CFA_offset_extended
:
443 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
444 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
445 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
446 offset
= utmp
* fs
->data_align
;
447 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
448 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
449 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
452 case DW_CFA_restore_extended
:
453 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
454 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
457 case DW_CFA_undefined
:
458 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
459 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
460 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
461 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNDEFINED
;
464 case DW_CFA_same_value
:
465 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
466 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
467 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
468 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAME_VALUE
;
471 case DW_CFA_register
:
472 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
473 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
474 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
475 utmp
= dwarf2_frame_adjust_regnum (gdbarch
, utmp
, eh_frame_p
);
476 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
477 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_REG
;
478 fs
->regs
.reg
[reg
].loc
.reg
= utmp
;
481 case DW_CFA_remember_state
:
483 struct dwarf2_frame_state_reg_info
*new_rs
;
485 new_rs
= XMALLOC (struct dwarf2_frame_state_reg_info
);
487 fs
->regs
.reg
= dwarf2_frame_state_copy_regs (&fs
->regs
);
488 fs
->regs
.prev
= new_rs
;
492 case DW_CFA_restore_state
:
494 struct dwarf2_frame_state_reg_info
*old_rs
= fs
->regs
.prev
;
498 complaint (&symfile_complaints
, _("\
499 bad CFI data; mismatched DW_CFA_restore_state at %s"),
500 paddress (gdbarch
, fs
->pc
));
504 xfree (fs
->regs
.reg
);
512 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &fs
->regs
.cfa_reg
);
513 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
515 if (fs
->armcc_cfa_offsets_sf
)
516 utmp
*= fs
->data_align
;
518 fs
->regs
.cfa_offset
= utmp
;
519 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
522 case DW_CFA_def_cfa_register
:
523 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &fs
->regs
.cfa_reg
);
524 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
,
527 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
530 case DW_CFA_def_cfa_offset
:
531 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
533 if (fs
->armcc_cfa_offsets_sf
)
534 utmp
*= fs
->data_align
;
536 fs
->regs
.cfa_offset
= utmp
;
537 /* cfa_how deliberately not set. */
543 case DW_CFA_def_cfa_expression
:
544 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
,
545 &fs
->regs
.cfa_exp_len
);
546 fs
->regs
.cfa_exp
= insn_ptr
;
547 fs
->regs
.cfa_how
= CFA_EXP
;
548 insn_ptr
+= fs
->regs
.cfa_exp_len
;
551 case DW_CFA_expression
:
552 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
553 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
554 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
555 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
556 fs
->regs
.reg
[reg
].loc
.exp
= insn_ptr
;
557 fs
->regs
.reg
[reg
].exp_len
= utmp
;
558 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_EXP
;
562 case DW_CFA_offset_extended_sf
:
563 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
564 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
565 insn_ptr
= read_sleb128 (insn_ptr
, insn_end
, &offset
);
566 offset
*= fs
->data_align
;
567 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
568 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
569 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
572 case DW_CFA_val_offset
:
573 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
574 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
575 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
576 offset
= utmp
* fs
->data_align
;
577 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_OFFSET
;
578 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
581 case DW_CFA_val_offset_sf
:
582 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
583 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
584 insn_ptr
= read_sleb128 (insn_ptr
, insn_end
, &offset
);
585 offset
*= fs
->data_align
;
586 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_OFFSET
;
587 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
590 case DW_CFA_val_expression
:
591 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
592 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
593 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
594 fs
->regs
.reg
[reg
].loc
.exp
= insn_ptr
;
595 fs
->regs
.reg
[reg
].exp_len
= utmp
;
596 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_EXP
;
600 case DW_CFA_def_cfa_sf
:
601 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &fs
->regs
.cfa_reg
);
602 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
,
605 insn_ptr
= read_sleb128 (insn_ptr
, insn_end
, &offset
);
606 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
607 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
610 case DW_CFA_def_cfa_offset_sf
:
611 insn_ptr
= read_sleb128 (insn_ptr
, insn_end
, &offset
);
612 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
613 /* cfa_how deliberately not set. */
616 case DW_CFA_GNU_window_save
:
617 /* This is SPARC-specific code, and contains hard-coded
618 constants for the register numbering scheme used by
619 GCC. Rather than having a architecture-specific
620 operation that's only ever used by a single
621 architecture, we provide the implementation here.
622 Incidentally that's what GCC does too in its
625 int size
= register_size (gdbarch
, 0);
626 dwarf2_frame_state_alloc_regs (&fs
->regs
, 32);
627 for (reg
= 8; reg
< 16; reg
++)
629 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_REG
;
630 fs
->regs
.reg
[reg
].loc
.reg
= reg
+ 16;
632 for (reg
= 16; reg
< 32; reg
++)
634 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
635 fs
->regs
.reg
[reg
].loc
.offset
= (reg
- 16) * size
;
640 case DW_CFA_GNU_args_size
:
642 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
645 case DW_CFA_GNU_negative_offset_extended
:
646 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
647 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
648 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &offset
);
649 offset
*= fs
->data_align
;
650 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
651 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
652 fs
->regs
.reg
[reg
].loc
.offset
= -offset
;
656 internal_error (__FILE__
, __LINE__
, _("Unknown CFI encountered."));
661 /* Don't allow remember/restore between CIE and FDE programs. */
662 dwarf2_frame_state_free_regs (fs
->regs
.prev
);
663 fs
->regs
.prev
= NULL
;
667 /* Architecture-specific operations. */
669 /* Per-architecture data key. */
670 static struct gdbarch_data
*dwarf2_frame_data
;
672 struct dwarf2_frame_ops
674 /* Pre-initialize the register state REG for register REGNUM. */
675 void (*init_reg
) (struct gdbarch
*, int, struct dwarf2_frame_state_reg
*,
676 struct frame_info
*);
678 /* Check whether the THIS_FRAME is a signal trampoline. */
679 int (*signal_frame_p
) (struct gdbarch
*, struct frame_info
*);
681 /* Convert .eh_frame register number to DWARF register number, or
682 adjust .debug_frame register number. */
683 int (*adjust_regnum
) (struct gdbarch
*, int, int);
686 /* Default architecture-specific register state initialization
690 dwarf2_frame_default_init_reg (struct gdbarch
*gdbarch
, int regnum
,
691 struct dwarf2_frame_state_reg
*reg
,
692 struct frame_info
*this_frame
)
694 /* If we have a register that acts as a program counter, mark it as
695 a destination for the return address. If we have a register that
696 serves as the stack pointer, arrange for it to be filled with the
697 call frame address (CFA). The other registers are marked as
700 We copy the return address to the program counter, since many
701 parts in GDB assume that it is possible to get the return address
702 by unwinding the program counter register. However, on ISA's
703 with a dedicated return address register, the CFI usually only
704 contains information to unwind that return address register.
706 The reason we're treating the stack pointer special here is
707 because in many cases GCC doesn't emit CFI for the stack pointer
708 and implicitly assumes that it is equal to the CFA. This makes
709 some sense since the DWARF specification (version 3, draft 8,
712 "Typically, the CFA is defined to be the value of the stack
713 pointer at the call site in the previous frame (which may be
714 different from its value on entry to the current frame)."
716 However, this isn't true for all platforms supported by GCC
717 (e.g. IBM S/390 and zSeries). Those architectures should provide
718 their own architecture-specific initialization function. */
720 if (regnum
== gdbarch_pc_regnum (gdbarch
))
721 reg
->how
= DWARF2_FRAME_REG_RA
;
722 else if (regnum
== gdbarch_sp_regnum (gdbarch
))
723 reg
->how
= DWARF2_FRAME_REG_CFA
;
726 /* Return a default for the architecture-specific operations. */
729 dwarf2_frame_init (struct obstack
*obstack
)
731 struct dwarf2_frame_ops
*ops
;
733 ops
= OBSTACK_ZALLOC (obstack
, struct dwarf2_frame_ops
);
734 ops
->init_reg
= dwarf2_frame_default_init_reg
;
738 /* Set the architecture-specific register state initialization
739 function for GDBARCH to INIT_REG. */
742 dwarf2_frame_set_init_reg (struct gdbarch
*gdbarch
,
743 void (*init_reg
) (struct gdbarch
*, int,
744 struct dwarf2_frame_state_reg
*,
745 struct frame_info
*))
747 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
749 ops
->init_reg
= init_reg
;
752 /* Pre-initialize the register state REG for register REGNUM. */
755 dwarf2_frame_init_reg (struct gdbarch
*gdbarch
, int regnum
,
756 struct dwarf2_frame_state_reg
*reg
,
757 struct frame_info
*this_frame
)
759 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
761 ops
->init_reg (gdbarch
, regnum
, reg
, this_frame
);
764 /* Set the architecture-specific signal trampoline recognition
765 function for GDBARCH to SIGNAL_FRAME_P. */
768 dwarf2_frame_set_signal_frame_p (struct gdbarch
*gdbarch
,
769 int (*signal_frame_p
) (struct gdbarch
*,
770 struct frame_info
*))
772 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
774 ops
->signal_frame_p
= signal_frame_p
;
777 /* Query the architecture-specific signal frame recognizer for
781 dwarf2_frame_signal_frame_p (struct gdbarch
*gdbarch
,
782 struct frame_info
*this_frame
)
784 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
786 if (ops
->signal_frame_p
== NULL
)
788 return ops
->signal_frame_p (gdbarch
, this_frame
);
791 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
795 dwarf2_frame_set_adjust_regnum (struct gdbarch
*gdbarch
,
796 int (*adjust_regnum
) (struct gdbarch
*,
799 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
801 ops
->adjust_regnum
= adjust_regnum
;
804 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
808 dwarf2_frame_adjust_regnum (struct gdbarch
*gdbarch
, int regnum
, int eh_frame_p
)
810 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
812 if (ops
->adjust_regnum
== NULL
)
814 return ops
->adjust_regnum (gdbarch
, regnum
, eh_frame_p
);
818 dwarf2_frame_find_quirks (struct dwarf2_frame_state
*fs
,
819 struct dwarf2_fde
*fde
)
821 static const char *arm_idents
[] = {
822 "ARM C Compiler, ADS",
823 "Thumb C Compiler, ADS",
824 "ARM C++ Compiler, ADS",
825 "Thumb C++ Compiler, ADS",
826 "ARM/Thumb C/C++ Compiler, RVCT"
832 s
= find_pc_symtab (fs
->pc
);
833 if (s
== NULL
|| s
->producer
== NULL
)
836 for (i
= 0; i
< ARRAY_SIZE (arm_idents
); i
++)
837 if (strncmp (s
->producer
, arm_idents
[i
], strlen (arm_idents
[i
])) == 0)
839 if (fde
->cie
->version
== 1)
840 fs
->armcc_cfa_offsets_sf
= 1;
842 if (fde
->cie
->version
== 1)
843 fs
->armcc_cfa_offsets_reversed
= 1;
845 /* The reversed offset problem is present in some compilers
846 using DWARF3, but it was eventually fixed. Check the ARM
847 defined augmentations, which are in the format "armcc" followed
848 by a list of one-character options. The "+" option means
849 this problem is fixed (no quirk needed). If the armcc
850 augmentation is missing, the quirk is needed. */
851 if (fde
->cie
->version
== 3
852 && (strncmp (fde
->cie
->augmentation
, "armcc", 5) != 0
853 || strchr (fde
->cie
->augmentation
+ 5, '+') == NULL
))
854 fs
->armcc_cfa_offsets_reversed
= 1;
861 struct dwarf2_frame_cache
863 /* DWARF Call Frame Address. */
866 /* Set if the return address column was marked as undefined. */
867 int undefined_retaddr
;
869 /* Saved registers, indexed by GDB register number, not by DWARF
871 struct dwarf2_frame_state_reg
*reg
;
873 /* Return address register. */
874 struct dwarf2_frame_state_reg retaddr_reg
;
876 /* Target address size in bytes. */
880 static struct dwarf2_frame_cache
*
881 dwarf2_frame_cache (struct frame_info
*this_frame
, void **this_cache
)
883 struct cleanup
*old_chain
;
884 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
885 const int num_regs
= gdbarch_num_regs (gdbarch
)
886 + gdbarch_num_pseudo_regs (gdbarch
);
887 struct dwarf2_frame_cache
*cache
;
888 struct dwarf2_frame_state
*fs
;
889 struct dwarf2_fde
*fde
;
894 /* Allocate a new cache. */
895 cache
= FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache
);
896 cache
->reg
= FRAME_OBSTACK_CALLOC (num_regs
, struct dwarf2_frame_state_reg
);
898 /* Allocate and initialize the frame state. */
899 fs
= XMALLOC (struct dwarf2_frame_state
);
900 memset (fs
, 0, sizeof (struct dwarf2_frame_state
));
901 old_chain
= make_cleanup (dwarf2_frame_state_free
, fs
);
905 Note that if the next frame is never supposed to return (i.e. a call
906 to abort), the compiler might optimize away the instruction at
907 its return address. As a result the return address will
908 point at some random instruction, and the CFI for that
909 instruction is probably worthless to us. GCC's unwinder solves
910 this problem by substracting 1 from the return address to get an
911 address in the middle of a presumed call instruction (or the
912 instruction in the associated delay slot). This should only be
913 done for "normal" frames and not for resume-type frames (signal
914 handlers, sentinel frames, dummy frames). The function
915 get_frame_address_in_block does just this. It's not clear how
916 reliable the method is though; there is the potential for the
917 register state pre-call being different to that on return. */
918 fs
->pc
= get_frame_address_in_block (this_frame
);
920 /* Find the correct FDE. */
921 fde
= dwarf2_frame_find_fde (&fs
->pc
);
922 gdb_assert (fde
!= NULL
);
924 /* Extract any interesting information from the CIE. */
925 fs
->data_align
= fde
->cie
->data_alignment_factor
;
926 fs
->code_align
= fde
->cie
->code_alignment_factor
;
927 fs
->retaddr_column
= fde
->cie
->return_address_register
;
928 cache
->addr_size
= fde
->cie
->addr_size
;
930 /* Check for "quirks" - known bugs in producers. */
931 dwarf2_frame_find_quirks (fs
, fde
);
933 /* First decode all the insns in the CIE. */
934 execute_cfa_program (fde
, fde
->cie
->initial_instructions
,
935 fde
->cie
->end
, this_frame
, fs
);
937 /* Save the initialized register set. */
938 fs
->initial
= fs
->regs
;
939 fs
->initial
.reg
= dwarf2_frame_state_copy_regs (&fs
->regs
);
941 /* Then decode the insns in the FDE up to our target PC. */
942 execute_cfa_program (fde
, fde
->instructions
, fde
->end
, this_frame
, fs
);
944 /* Calculate the CFA. */
945 switch (fs
->regs
.cfa_how
)
948 cache
->cfa
= read_reg (this_frame
, fs
->regs
.cfa_reg
);
949 if (fs
->armcc_cfa_offsets_reversed
)
950 cache
->cfa
-= fs
->regs
.cfa_offset
;
952 cache
->cfa
+= fs
->regs
.cfa_offset
;
957 execute_stack_op (fs
->regs
.cfa_exp
, fs
->regs
.cfa_exp_len
,
958 cache
->addr_size
, this_frame
, 0);
962 internal_error (__FILE__
, __LINE__
, _("Unknown CFA rule."));
965 /* Initialize the register state. */
969 for (regnum
= 0; regnum
< num_regs
; regnum
++)
970 dwarf2_frame_init_reg (gdbarch
, regnum
, &cache
->reg
[regnum
], this_frame
);
973 /* Go through the DWARF2 CFI generated table and save its register
974 location information in the cache. Note that we don't skip the
975 return address column; it's perfectly all right for it to
976 correspond to a real register. If it doesn't correspond to a
977 real register, or if we shouldn't treat it as such,
978 gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside
979 the range [0, gdbarch_num_regs). */
981 int column
; /* CFI speak for "register number". */
983 for (column
= 0; column
< fs
->regs
.num_regs
; column
++)
985 /* Use the GDB register number as the destination index. */
986 int regnum
= gdbarch_dwarf2_reg_to_regnum (gdbarch
, column
);
988 /* If there's no corresponding GDB register, ignore it. */
989 if (regnum
< 0 || regnum
>= num_regs
)
992 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
993 of all debug info registers. If it doesn't, complain (but
994 not too loudly). It turns out that GCC assumes that an
995 unspecified register implies "same value" when CFI (draft
996 7) specifies nothing at all. Such a register could equally
997 be interpreted as "undefined". Also note that this check
998 isn't sufficient; it only checks that all registers in the
999 range [0 .. max column] are specified, and won't detect
1000 problems when a debug info register falls outside of the
1001 table. We need a way of iterating through all the valid
1002 DWARF2 register numbers. */
1003 if (fs
->regs
.reg
[column
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
1005 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
1006 complaint (&symfile_complaints
, _("\
1007 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1008 gdbarch_register_name (gdbarch
, regnum
),
1009 paddress (gdbarch
, fs
->pc
));
1012 cache
->reg
[regnum
] = fs
->regs
.reg
[column
];
1016 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1017 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1021 for (regnum
= 0; regnum
< num_regs
; regnum
++)
1023 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
1024 || cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA_OFFSET
)
1026 struct dwarf2_frame_state_reg
*retaddr_reg
=
1027 &fs
->regs
.reg
[fs
->retaddr_column
];
1029 /* It seems rather bizarre to specify an "empty" column as
1030 the return adress column. However, this is exactly
1031 what GCC does on some targets. It turns out that GCC
1032 assumes that the return address can be found in the
1033 register corresponding to the return address column.
1034 Incidentally, that's how we should treat a return
1035 address column specifying "same value" too. */
1036 if (fs
->retaddr_column
< fs
->regs
.num_regs
1037 && retaddr_reg
->how
!= DWARF2_FRAME_REG_UNSPECIFIED
1038 && retaddr_reg
->how
!= DWARF2_FRAME_REG_SAME_VALUE
)
1040 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1041 cache
->reg
[regnum
] = *retaddr_reg
;
1043 cache
->retaddr_reg
= *retaddr_reg
;
1047 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1049 cache
->reg
[regnum
].loc
.reg
= fs
->retaddr_column
;
1050 cache
->reg
[regnum
].how
= DWARF2_FRAME_REG_SAVED_REG
;
1054 cache
->retaddr_reg
.loc
.reg
= fs
->retaddr_column
;
1055 cache
->retaddr_reg
.how
= DWARF2_FRAME_REG_SAVED_REG
;
1062 if (fs
->retaddr_column
< fs
->regs
.num_regs
1063 && fs
->regs
.reg
[fs
->retaddr_column
].how
== DWARF2_FRAME_REG_UNDEFINED
)
1064 cache
->undefined_retaddr
= 1;
1066 do_cleanups (old_chain
);
1068 *this_cache
= cache
;
1073 dwarf2_frame_this_id (struct frame_info
*this_frame
, void **this_cache
,
1074 struct frame_id
*this_id
)
1076 struct dwarf2_frame_cache
*cache
=
1077 dwarf2_frame_cache (this_frame
, this_cache
);
1079 if (cache
->undefined_retaddr
)
1082 (*this_id
) = frame_id_build (cache
->cfa
, get_frame_func (this_frame
));
1085 static struct value
*
1086 dwarf2_frame_prev_register (struct frame_info
*this_frame
, void **this_cache
,
1089 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
1090 struct dwarf2_frame_cache
*cache
=
1091 dwarf2_frame_cache (this_frame
, this_cache
);
1095 switch (cache
->reg
[regnum
].how
)
1097 case DWARF2_FRAME_REG_UNDEFINED
:
1098 /* If CFI explicitly specified that the value isn't defined,
1099 mark it as optimized away; the value isn't available. */
1100 return frame_unwind_got_optimized (this_frame
, regnum
);
1102 case DWARF2_FRAME_REG_SAVED_OFFSET
:
1103 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1104 return frame_unwind_got_memory (this_frame
, regnum
, addr
);
1106 case DWARF2_FRAME_REG_SAVED_REG
:
1108 = gdbarch_dwarf2_reg_to_regnum (gdbarch
, cache
->reg
[regnum
].loc
.reg
);
1109 return frame_unwind_got_register (this_frame
, regnum
, realnum
);
1111 case DWARF2_FRAME_REG_SAVED_EXP
:
1112 addr
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
,
1113 cache
->reg
[regnum
].exp_len
,
1114 cache
->addr_size
, this_frame
, cache
->cfa
);
1115 return frame_unwind_got_memory (this_frame
, regnum
, addr
);
1117 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET
:
1118 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1119 return frame_unwind_got_constant (this_frame
, regnum
, addr
);
1121 case DWARF2_FRAME_REG_SAVED_VAL_EXP
:
1122 addr
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
,
1123 cache
->reg
[regnum
].exp_len
,
1124 cache
->addr_size
, this_frame
, cache
->cfa
);
1125 return frame_unwind_got_constant (this_frame
, regnum
, addr
);
1127 case DWARF2_FRAME_REG_UNSPECIFIED
:
1128 /* GCC, in its infinite wisdom decided to not provide unwind
1129 information for registers that are "same value". Since
1130 DWARF2 (3 draft 7) doesn't define such behavior, said
1131 registers are actually undefined (which is different to CFI
1132 "undefined"). Code above issues a complaint about this.
1133 Here just fudge the books, assume GCC, and that the value is
1134 more inner on the stack. */
1135 return frame_unwind_got_register (this_frame
, regnum
, regnum
);
1137 case DWARF2_FRAME_REG_SAME_VALUE
:
1138 return frame_unwind_got_register (this_frame
, regnum
, regnum
);
1140 case DWARF2_FRAME_REG_CFA
:
1141 return frame_unwind_got_address (this_frame
, regnum
, cache
->cfa
);
1143 case DWARF2_FRAME_REG_CFA_OFFSET
:
1144 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1145 return frame_unwind_got_address (this_frame
, regnum
, addr
);
1147 case DWARF2_FRAME_REG_RA_OFFSET
:
1148 addr
= cache
->reg
[regnum
].loc
.offset
;
1149 regnum
= gdbarch_dwarf2_reg_to_regnum
1150 (gdbarch
, cache
->retaddr_reg
.loc
.reg
);
1151 addr
+= get_frame_register_unsigned (this_frame
, regnum
);
1152 return frame_unwind_got_address (this_frame
, regnum
, addr
);
1154 case DWARF2_FRAME_REG_FN
:
1155 return cache
->reg
[regnum
].loc
.fn (this_frame
, this_cache
, regnum
);
1158 internal_error (__FILE__
, __LINE__
, _("Unknown register rule."));
1163 dwarf2_frame_sniffer (const struct frame_unwind
*self
,
1164 struct frame_info
*this_frame
, void **this_cache
)
1166 /* Grab an address that is guarenteed to reside somewhere within the
1167 function. get_frame_pc(), with a no-return next function, can
1168 end up returning something past the end of this function's body.
1169 If the frame we're sniffing for is a signal frame whose start
1170 address is placed on the stack by the OS, its FDE must
1171 extend one byte before its start address or we could potentially
1172 select the FDE of the previous function. */
1173 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1174 struct dwarf2_fde
*fde
= dwarf2_frame_find_fde (&block_addr
);
1178 /* On some targets, signal trampolines may have unwind information.
1179 We need to recognize them so that we set the frame type
1182 if (fde
->cie
->signal_frame
1183 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame
),
1185 return self
->type
== SIGTRAMP_FRAME
;
1187 return self
->type
!= SIGTRAMP_FRAME
;
1190 static const struct frame_unwind dwarf2_frame_unwind
=
1193 dwarf2_frame_this_id
,
1194 dwarf2_frame_prev_register
,
1196 dwarf2_frame_sniffer
1199 static const struct frame_unwind dwarf2_signal_frame_unwind
=
1202 dwarf2_frame_this_id
,
1203 dwarf2_frame_prev_register
,
1205 dwarf2_frame_sniffer
1208 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1211 dwarf2_append_unwinders (struct gdbarch
*gdbarch
)
1213 frame_unwind_append_unwinder (gdbarch
, &dwarf2_frame_unwind
);
1214 frame_unwind_append_unwinder (gdbarch
, &dwarf2_signal_frame_unwind
);
1218 /* There is no explicitly defined relationship between the CFA and the
1219 location of frame's local variables and arguments/parameters.
1220 Therefore, frame base methods on this page should probably only be
1221 used as a last resort, just to avoid printing total garbage as a
1222 response to the "info frame" command. */
1225 dwarf2_frame_base_address (struct frame_info
*this_frame
, void **this_cache
)
1227 struct dwarf2_frame_cache
*cache
=
1228 dwarf2_frame_cache (this_frame
, this_cache
);
1233 static const struct frame_base dwarf2_frame_base
=
1235 &dwarf2_frame_unwind
,
1236 dwarf2_frame_base_address
,
1237 dwarf2_frame_base_address
,
1238 dwarf2_frame_base_address
1241 const struct frame_base
*
1242 dwarf2_frame_base_sniffer (struct frame_info
*this_frame
)
1244 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1245 if (dwarf2_frame_find_fde (&block_addr
))
1246 return &dwarf2_frame_base
;
1251 const struct objfile_data
*dwarf2_frame_objfile_data
;
1254 read_1_byte (bfd
*abfd
, gdb_byte
*buf
)
1256 return bfd_get_8 (abfd
, buf
);
1260 read_4_bytes (bfd
*abfd
, gdb_byte
*buf
)
1262 return bfd_get_32 (abfd
, buf
);
1266 read_8_bytes (bfd
*abfd
, gdb_byte
*buf
)
1268 return bfd_get_64 (abfd
, buf
);
1272 read_unsigned_leb128 (bfd
*abfd
, gdb_byte
*buf
, unsigned int *bytes_read_ptr
)
1275 unsigned int num_read
;
1285 byte
= bfd_get_8 (abfd
, (bfd_byte
*) buf
);
1288 result
|= ((byte
& 0x7f) << shift
);
1291 while (byte
& 0x80);
1293 *bytes_read_ptr
= num_read
;
1299 read_signed_leb128 (bfd
*abfd
, gdb_byte
*buf
, unsigned int *bytes_read_ptr
)
1303 unsigned int num_read
;
1312 byte
= bfd_get_8 (abfd
, (bfd_byte
*) buf
);
1315 result
|= ((byte
& 0x7f) << shift
);
1318 while (byte
& 0x80);
1320 if (shift
< 8 * sizeof (result
) && (byte
& 0x40))
1321 result
|= -(((LONGEST
)1) << shift
);
1323 *bytes_read_ptr
= num_read
;
1329 read_initial_length (bfd
*abfd
, gdb_byte
*buf
, unsigned int *bytes_read_ptr
)
1333 result
= bfd_get_32 (abfd
, buf
);
1334 if (result
== 0xffffffff)
1336 result
= bfd_get_64 (abfd
, buf
+ 4);
1337 *bytes_read_ptr
= 12;
1340 *bytes_read_ptr
= 4;
1346 /* Pointer encoding helper functions. */
1348 /* GCC supports exception handling based on DWARF2 CFI. However, for
1349 technical reasons, it encodes addresses in its FDE's in a different
1350 way. Several "pointer encodings" are supported. The encoding
1351 that's used for a particular FDE is determined by the 'R'
1352 augmentation in the associated CIE. The argument of this
1353 augmentation is a single byte.
1355 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1356 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1357 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1358 address should be interpreted (absolute, relative to the current
1359 position in the FDE, ...). Bit 7, indicates that the address
1360 should be dereferenced. */
1363 encoding_for_size (unsigned int size
)
1368 return DW_EH_PE_udata2
;
1370 return DW_EH_PE_udata4
;
1372 return DW_EH_PE_udata8
;
1374 internal_error (__FILE__
, __LINE__
, _("Unsupported address size"));
1379 read_encoded_value (struct comp_unit
*unit
, gdb_byte encoding
,
1380 int ptr_len
, gdb_byte
*buf
, unsigned int *bytes_read_ptr
,
1381 CORE_ADDR func_base
)
1386 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1388 if (encoding
& DW_EH_PE_indirect
)
1389 internal_error (__FILE__
, __LINE__
,
1390 _("Unsupported encoding: DW_EH_PE_indirect"));
1392 *bytes_read_ptr
= 0;
1394 switch (encoding
& 0x70)
1396 case DW_EH_PE_absptr
:
1399 case DW_EH_PE_pcrel
:
1400 base
= bfd_get_section_vma (unit
->abfd
, unit
->dwarf_frame_section
);
1401 base
+= (buf
- unit
->dwarf_frame_buffer
);
1403 case DW_EH_PE_datarel
:
1406 case DW_EH_PE_textrel
:
1409 case DW_EH_PE_funcrel
:
1412 case DW_EH_PE_aligned
:
1414 offset
= buf
- unit
->dwarf_frame_buffer
;
1415 if ((offset
% ptr_len
) != 0)
1417 *bytes_read_ptr
= ptr_len
- (offset
% ptr_len
);
1418 buf
+= *bytes_read_ptr
;
1422 internal_error (__FILE__
, __LINE__
, _("Invalid or unsupported encoding"));
1425 if ((encoding
& 0x07) == 0x00)
1427 encoding
|= encoding_for_size (ptr_len
);
1428 if (bfd_get_sign_extend_vma (unit
->abfd
))
1429 encoding
|= DW_EH_PE_signed
;
1432 switch (encoding
& 0x0f)
1434 case DW_EH_PE_uleb128
:
1437 gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1438 *bytes_read_ptr
+= read_uleb128 (buf
, end_buf
, &value
) - buf
;
1439 return base
+ value
;
1441 case DW_EH_PE_udata2
:
1442 *bytes_read_ptr
+= 2;
1443 return (base
+ bfd_get_16 (unit
->abfd
, (bfd_byte
*) buf
));
1444 case DW_EH_PE_udata4
:
1445 *bytes_read_ptr
+= 4;
1446 return (base
+ bfd_get_32 (unit
->abfd
, (bfd_byte
*) buf
));
1447 case DW_EH_PE_udata8
:
1448 *bytes_read_ptr
+= 8;
1449 return (base
+ bfd_get_64 (unit
->abfd
, (bfd_byte
*) buf
));
1450 case DW_EH_PE_sleb128
:
1453 gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1454 *bytes_read_ptr
+= read_sleb128 (buf
, end_buf
, &value
) - buf
;
1455 return base
+ value
;
1457 case DW_EH_PE_sdata2
:
1458 *bytes_read_ptr
+= 2;
1459 return (base
+ bfd_get_signed_16 (unit
->abfd
, (bfd_byte
*) buf
));
1460 case DW_EH_PE_sdata4
:
1461 *bytes_read_ptr
+= 4;
1462 return (base
+ bfd_get_signed_32 (unit
->abfd
, (bfd_byte
*) buf
));
1463 case DW_EH_PE_sdata8
:
1464 *bytes_read_ptr
+= 8;
1465 return (base
+ bfd_get_signed_64 (unit
->abfd
, (bfd_byte
*) buf
));
1467 internal_error (__FILE__
, __LINE__
, _("Invalid or unsupported encoding"));
1473 bsearch_cie_cmp (const void *key
, const void *element
)
1475 ULONGEST cie_pointer
= *(ULONGEST
*) key
;
1476 struct dwarf2_cie
*cie
= *(struct dwarf2_cie
**) element
;
1478 if (cie_pointer
== cie
->cie_pointer
)
1481 return (cie_pointer
< cie
->cie_pointer
) ? -1 : 1;
1484 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1485 static struct dwarf2_cie
*
1486 find_cie (struct dwarf2_cie_table
*cie_table
, ULONGEST cie_pointer
)
1488 struct dwarf2_cie
**p_cie
;
1490 p_cie
= bsearch (&cie_pointer
, cie_table
->entries
, cie_table
->num_entries
,
1491 sizeof (cie_table
->entries
[0]), bsearch_cie_cmp
);
1497 /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1499 add_cie (struct dwarf2_cie_table
*cie_table
, struct dwarf2_cie
*cie
)
1501 const int n
= cie_table
->num_entries
;
1504 || cie_table
->entries
[n
- 1]->cie_pointer
< cie
->cie_pointer
);
1506 cie_table
->entries
=
1507 xrealloc (cie_table
->entries
, (n
+ 1) * sizeof (cie_table
->entries
[0]));
1508 cie_table
->entries
[n
] = cie
;
1509 cie_table
->num_entries
= n
+ 1;
1513 bsearch_fde_cmp (const void *key
, const void *element
)
1515 CORE_ADDR seek_pc
= *(CORE_ADDR
*) key
;
1516 struct dwarf2_fde
*fde
= *(struct dwarf2_fde
**) element
;
1517 if (seek_pc
< fde
->initial_location
)
1519 if (seek_pc
< fde
->initial_location
+ fde
->address_range
)
1524 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1525 inital location associated with it into *PC. */
1527 static struct dwarf2_fde
*
1528 dwarf2_frame_find_fde (CORE_ADDR
*pc
)
1530 struct objfile
*objfile
;
1532 ALL_OBJFILES (objfile
)
1534 struct dwarf2_fde_table
*fde_table
;
1535 struct dwarf2_fde
**p_fde
;
1539 fde_table
= objfile_data (objfile
, dwarf2_frame_objfile_data
);
1540 if (fde_table
== NULL
)
1543 gdb_assert (objfile
->section_offsets
);
1544 offset
= ANOFFSET (objfile
->section_offsets
, SECT_OFF_TEXT (objfile
));
1546 gdb_assert (fde_table
->num_entries
> 0);
1547 if (*pc
< offset
+ fde_table
->entries
[0]->initial_location
)
1550 seek_pc
= *pc
- offset
;
1551 p_fde
= bsearch (&seek_pc
, fde_table
->entries
, fde_table
->num_entries
,
1552 sizeof (fde_table
->entries
[0]), bsearch_fde_cmp
);
1555 *pc
= (*p_fde
)->initial_location
+ offset
;
1562 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1564 add_fde (struct dwarf2_fde_table
*fde_table
, struct dwarf2_fde
*fde
)
1566 if (fde
->address_range
== 0)
1567 /* Discard useless FDEs. */
1570 fde_table
->num_entries
+= 1;
1571 fde_table
->entries
=
1572 xrealloc (fde_table
->entries
,
1573 fde_table
->num_entries
* sizeof (fde_table
->entries
[0]));
1574 fde_table
->entries
[fde_table
->num_entries
- 1] = fde
;
1577 #ifdef CC_HAS_LONG_LONG
1578 #define DW64_CIE_ID 0xffffffffffffffffULL
1580 #define DW64_CIE_ID ~0
1583 static gdb_byte
*decode_frame_entry (struct comp_unit
*unit
, gdb_byte
*start
,
1585 struct dwarf2_cie_table
*cie_table
,
1586 struct dwarf2_fde_table
*fde_table
);
1588 /* Decode the next CIE or FDE. Return NULL if invalid input, otherwise
1589 the next byte to be processed. */
1591 decode_frame_entry_1 (struct comp_unit
*unit
, gdb_byte
*start
, int eh_frame_p
,
1592 struct dwarf2_cie_table
*cie_table
,
1593 struct dwarf2_fde_table
*fde_table
)
1595 struct gdbarch
*gdbarch
= get_objfile_arch (unit
->objfile
);
1596 gdb_byte
*buf
, *end
;
1598 unsigned int bytes_read
;
1601 ULONGEST cie_pointer
;
1604 length
= read_initial_length (unit
->abfd
, buf
, &bytes_read
);
1608 /* Are we still within the section? */
1609 if (end
> unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
1615 /* Distinguish between 32 and 64-bit encoded frame info. */
1616 dwarf64_p
= (bytes_read
== 12);
1618 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1622 cie_id
= DW64_CIE_ID
;
1628 cie_pointer
= read_8_bytes (unit
->abfd
, buf
);
1633 cie_pointer
= read_4_bytes (unit
->abfd
, buf
);
1637 if (cie_pointer
== cie_id
)
1639 /* This is a CIE. */
1640 struct dwarf2_cie
*cie
;
1642 unsigned int cie_version
;
1644 /* Record the offset into the .debug_frame section of this CIE. */
1645 cie_pointer
= start
- unit
->dwarf_frame_buffer
;
1647 /* Check whether we've already read it. */
1648 if (find_cie (cie_table
, cie_pointer
))
1651 cie
= (struct dwarf2_cie
*)
1652 obstack_alloc (&unit
->objfile
->objfile_obstack
,
1653 sizeof (struct dwarf2_cie
));
1654 cie
->initial_instructions
= NULL
;
1655 cie
->cie_pointer
= cie_pointer
;
1657 /* The encoding for FDE's in a normal .debug_frame section
1658 depends on the target address size. */
1659 cie
->encoding
= DW_EH_PE_absptr
;
1661 /* The target address size. For .eh_frame FDEs this is considered
1662 equal to the size of a target pointer. For .dwarf_frame FDEs,
1663 this is supposed to be the target address size from the associated
1664 CU header. FIXME: We do not have a good way to determine the
1665 latter. Always use the target pointer size for now. */
1666 cie
->addr_size
= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1668 /* We'll determine the final value later, but we need to
1669 initialize it conservatively. */
1670 cie
->signal_frame
= 0;
1672 /* Check version number. */
1673 cie_version
= read_1_byte (unit
->abfd
, buf
);
1674 if (cie_version
!= 1 && cie_version
!= 3)
1676 cie
->version
= cie_version
;
1679 /* Interpret the interesting bits of the augmentation. */
1680 cie
->augmentation
= augmentation
= (char *) buf
;
1681 buf
+= (strlen (augmentation
) + 1);
1683 /* Ignore armcc augmentations. We only use them for quirks,
1684 and that doesn't happen until later. */
1685 if (strncmp (augmentation
, "armcc", 5) == 0)
1686 augmentation
+= strlen (augmentation
);
1688 /* The GCC 2.x "eh" augmentation has a pointer immediately
1689 following the augmentation string, so it must be handled
1691 if (augmentation
[0] == 'e' && augmentation
[1] == 'h')
1694 buf
+= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1698 cie
->code_alignment_factor
=
1699 read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1702 cie
->data_alignment_factor
=
1703 read_signed_leb128 (unit
->abfd
, buf
, &bytes_read
);
1706 if (cie_version
== 1)
1708 cie
->return_address_register
= read_1_byte (unit
->abfd
, buf
);
1712 cie
->return_address_register
= read_unsigned_leb128 (unit
->abfd
, buf
,
1714 cie
->return_address_register
1715 = dwarf2_frame_adjust_regnum (gdbarch
,
1716 cie
->return_address_register
,
1721 cie
->saw_z_augmentation
= (*augmentation
== 'z');
1722 if (cie
->saw_z_augmentation
)
1726 length
= read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1730 cie
->initial_instructions
= buf
+ length
;
1734 while (*augmentation
)
1736 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1737 if (*augmentation
== 'L')
1744 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1745 else if (*augmentation
== 'R')
1747 cie
->encoding
= *buf
++;
1751 /* "P" indicates a personality routine in the CIE augmentation. */
1752 else if (*augmentation
== 'P')
1754 /* Skip. Avoid indirection since we throw away the result. */
1755 gdb_byte encoding
= (*buf
++) & ~DW_EH_PE_indirect
;
1756 read_encoded_value (unit
, encoding
, cie
->addr_size
,
1757 buf
, &bytes_read
, 0);
1762 /* "S" indicates a signal frame, such that the return
1763 address must not be decremented to locate the call frame
1764 info for the previous frame; it might even be the first
1765 instruction of a function, so decrementing it would take
1766 us to a different function. */
1767 else if (*augmentation
== 'S')
1769 cie
->signal_frame
= 1;
1773 /* Otherwise we have an unknown augmentation. Assume that either
1774 there is no augmentation data, or we saw a 'z' prefix. */
1777 if (cie
->initial_instructions
)
1778 buf
= cie
->initial_instructions
;
1783 cie
->initial_instructions
= buf
;
1787 add_cie (cie_table
, cie
);
1791 /* This is a FDE. */
1792 struct dwarf2_fde
*fde
;
1794 /* In an .eh_frame section, the CIE pointer is the delta between the
1795 address within the FDE where the CIE pointer is stored and the
1796 address of the CIE. Convert it to an offset into the .eh_frame
1800 cie_pointer
= buf
- unit
->dwarf_frame_buffer
- cie_pointer
;
1801 cie_pointer
-= (dwarf64_p
? 8 : 4);
1804 /* In either case, validate the result is still within the section. */
1805 if (cie_pointer
>= unit
->dwarf_frame_size
)
1808 fde
= (struct dwarf2_fde
*)
1809 obstack_alloc (&unit
->objfile
->objfile_obstack
,
1810 sizeof (struct dwarf2_fde
));
1811 fde
->cie
= find_cie (cie_table
, cie_pointer
);
1812 if (fde
->cie
== NULL
)
1814 decode_frame_entry (unit
, unit
->dwarf_frame_buffer
+ cie_pointer
,
1815 eh_frame_p
, cie_table
, fde_table
);
1816 fde
->cie
= find_cie (cie_table
, cie_pointer
);
1819 gdb_assert (fde
->cie
!= NULL
);
1821 fde
->initial_location
=
1822 read_encoded_value (unit
, fde
->cie
->encoding
, fde
->cie
->addr_size
,
1823 buf
, &bytes_read
, 0);
1826 fde
->address_range
=
1827 read_encoded_value (unit
, fde
->cie
->encoding
& 0x0f,
1828 fde
->cie
->addr_size
, buf
, &bytes_read
, 0);
1831 /* A 'z' augmentation in the CIE implies the presence of an
1832 augmentation field in the FDE as well. The only thing known
1833 to be in here at present is the LSDA entry for EH. So we
1834 can skip the whole thing. */
1835 if (fde
->cie
->saw_z_augmentation
)
1839 length
= read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1840 buf
+= bytes_read
+ length
;
1845 fde
->instructions
= buf
;
1848 fde
->eh_frame_p
= eh_frame_p
;
1850 add_fde (fde_table
, fde
);
1856 /* Read a CIE or FDE in BUF and decode it. */
1858 decode_frame_entry (struct comp_unit
*unit
, gdb_byte
*start
, int eh_frame_p
,
1859 struct dwarf2_cie_table
*cie_table
,
1860 struct dwarf2_fde_table
*fde_table
)
1862 enum { NONE
, ALIGN4
, ALIGN8
, FAIL
} workaround
= NONE
;
1865 ptrdiff_t start_offset
;
1869 ret
= decode_frame_entry_1 (unit
, start
, eh_frame_p
,
1870 cie_table
, fde_table
);
1874 /* We have corrupt input data of some form. */
1876 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
1877 and mismatches wrt padding and alignment of debug sections. */
1878 /* Note that there is no requirement in the standard for any
1879 alignment at all in the frame unwind sections. Testing for
1880 alignment before trying to interpret data would be incorrect.
1882 However, GCC traditionally arranged for frame sections to be
1883 sized such that the FDE length and CIE fields happen to be
1884 aligned (in theory, for performance). This, unfortunately,
1885 was done with .align directives, which had the side effect of
1886 forcing the section to be aligned by the linker.
1888 This becomes a problem when you have some other producer that
1889 creates frame sections that are not as strictly aligned. That
1890 produces a hole in the frame info that gets filled by the
1893 The GCC behaviour is arguably a bug, but it's effectively now
1894 part of the ABI, so we're now stuck with it, at least at the
1895 object file level. A smart linker may decide, in the process
1896 of compressing duplicate CIE information, that it can rewrite
1897 the entire output section without this extra padding. */
1899 start_offset
= start
- unit
->dwarf_frame_buffer
;
1900 if (workaround
< ALIGN4
&& (start_offset
& 3) != 0)
1902 start
+= 4 - (start_offset
& 3);
1903 workaround
= ALIGN4
;
1906 if (workaround
< ALIGN8
&& (start_offset
& 7) != 0)
1908 start
+= 8 - (start_offset
& 7);
1909 workaround
= ALIGN8
;
1913 /* Nothing left to try. Arrange to return as if we've consumed
1914 the entire input section. Hopefully we'll get valid info from
1915 the other of .debug_frame/.eh_frame. */
1917 ret
= unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
;
1927 complaint (&symfile_complaints
,
1928 _("Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
1929 unit
->dwarf_frame_section
->owner
->filename
,
1930 unit
->dwarf_frame_section
->name
);
1934 complaint (&symfile_complaints
,
1935 _("Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
1936 unit
->dwarf_frame_section
->owner
->filename
,
1937 unit
->dwarf_frame_section
->name
);
1941 complaint (&symfile_complaints
,
1942 _("Corrupt data in %s:%s"),
1943 unit
->dwarf_frame_section
->owner
->filename
,
1944 unit
->dwarf_frame_section
->name
);
1952 /* Imported from dwarf2read.c. */
1953 extern void dwarf2_get_section_info (struct objfile
*, const char *, asection
**,
1954 gdb_byte
**, bfd_size_type
*);
1957 qsort_fde_cmp (const void *a
, const void *b
)
1959 struct dwarf2_fde
*aa
= *(struct dwarf2_fde
**)a
;
1960 struct dwarf2_fde
*bb
= *(struct dwarf2_fde
**)b
;
1961 if (aa
->initial_location
== bb
->initial_location
)
1962 /* Put eh_frame entries after debug_frame ones. */
1963 return aa
->eh_frame_p
- bb
->eh_frame_p
;
1965 return (aa
->initial_location
< bb
->initial_location
) ? -1 : 1;
1969 dwarf2_build_frame_info (struct objfile
*objfile
)
1971 struct comp_unit
*unit
;
1972 gdb_byte
*frame_ptr
;
1973 struct dwarf2_cie_table cie_table
;
1974 struct dwarf2_fde_table fde_table
;
1976 cie_table
.num_entries
= 0;
1977 cie_table
.entries
= NULL
;
1979 fde_table
.num_entries
= 0;
1980 fde_table
.entries
= NULL
;
1982 /* Build a minimal decoding of the DWARF2 compilation unit. */
1983 unit
= (struct comp_unit
*) obstack_alloc (&objfile
->objfile_obstack
,
1984 sizeof (struct comp_unit
));
1985 unit
->abfd
= objfile
->obfd
;
1986 unit
->objfile
= objfile
;
1990 dwarf2_get_section_info (objfile
, ".eh_frame",
1991 &unit
->dwarf_frame_section
,
1992 &unit
->dwarf_frame_buffer
,
1993 &unit
->dwarf_frame_size
);
1994 if (unit
->dwarf_frame_size
)
1996 asection
*got
, *txt
;
1998 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
1999 that is used for the i386/amd64 target, which currently is
2000 the only target in GCC that supports/uses the
2001 DW_EH_PE_datarel encoding. */
2002 got
= bfd_get_section_by_name (unit
->abfd
, ".got");
2004 unit
->dbase
= got
->vma
;
2006 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2008 txt
= bfd_get_section_by_name (unit
->abfd
, ".text");
2010 unit
->tbase
= txt
->vma
;
2012 frame_ptr
= unit
->dwarf_frame_buffer
;
2013 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2014 frame_ptr
= decode_frame_entry (unit
, frame_ptr
, 1,
2015 &cie_table
, &fde_table
);
2017 if (cie_table
.num_entries
!= 0)
2019 /* Reinit cie_table: debug_frame has different CIEs. */
2020 xfree (cie_table
.entries
);
2021 cie_table
.num_entries
= 0;
2022 cie_table
.entries
= NULL
;
2026 dwarf2_get_section_info (objfile
, ".debug_frame",
2027 &unit
->dwarf_frame_section
,
2028 &unit
->dwarf_frame_buffer
,
2029 &unit
->dwarf_frame_size
);
2030 if (unit
->dwarf_frame_size
)
2032 frame_ptr
= unit
->dwarf_frame_buffer
;
2033 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2034 frame_ptr
= decode_frame_entry (unit
, frame_ptr
, 0,
2035 &cie_table
, &fde_table
);
2038 /* Discard the cie_table, it is no longer needed. */
2039 if (cie_table
.num_entries
!= 0)
2041 xfree (cie_table
.entries
);
2042 cie_table
.entries
= NULL
; /* Paranoia. */
2043 cie_table
.num_entries
= 0; /* Paranoia. */
2046 if (fde_table
.num_entries
!= 0)
2048 struct dwarf2_fde_table
*fde_table2
;
2051 /* Prepare FDE table for lookups. */
2052 qsort (fde_table
.entries
, fde_table
.num_entries
,
2053 sizeof (fde_table
.entries
[0]), qsort_fde_cmp
);
2055 /* Copy fde_table to obstack: it is needed at runtime. */
2056 fde_table2
= (struct dwarf2_fde_table
*)
2057 obstack_alloc (&objfile
->objfile_obstack
, sizeof (*fde_table2
));
2059 /* Since we'll be doing bsearch, squeeze out identical (except for
2060 eh_frame_p) fde entries so bsearch result is predictable. */
2061 for (i
= 0, j
= 0; j
< fde_table
.num_entries
; ++i
)
2065 obstack_grow (&objfile
->objfile_obstack
, &fde_table
.entries
[j
],
2066 sizeof (fde_table
.entries
[0]));
2067 while (++j
< fde_table
.num_entries
2068 && (fde_table
.entries
[k
]->initial_location
==
2069 fde_table
.entries
[j
]->initial_location
))
2072 fde_table2
->entries
= obstack_finish (&objfile
->objfile_obstack
);
2073 fde_table2
->num_entries
= i
;
2074 set_objfile_data (objfile
, dwarf2_frame_objfile_data
, fde_table2
);
2076 /* Discard the original fde_table. */
2077 xfree (fde_table
.entries
);
2081 /* Provide a prototype to silence -Wmissing-prototypes. */
2082 void _initialize_dwarf2_frame (void);
2085 _initialize_dwarf2_frame (void)
2087 dwarf2_frame_data
= gdbarch_data_register_pre_init (dwarf2_frame_init
);
2088 dwarf2_frame_objfile_data
= register_objfile_data ();