1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright (C) 2003-2017 Free Software Foundation, Inc.
5 Contributed by Mark Kettenis.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "dwarf2expr.h"
26 #include "frame-base.h"
27 #include "frame-unwind.h"
36 #include "complaints.h"
37 #include "dwarf2-frame.h"
39 #include "dwarf2loc.h"
40 #include "dwarf2-frame-tailcall.h"
43 #include "selftest-arch.h"
48 /* Call Frame Information (CFI). */
50 /* Common Information Entry (CIE). */
54 /* Computation Unit for this CIE. */
55 struct comp_unit
*unit
;
57 /* Offset into the .debug_frame section where this CIE was found.
58 Used to identify this CIE. */
61 /* Constant that is factored out of all advance location
63 ULONGEST code_alignment_factor
;
65 /* Constants that is factored out of all offset instructions. */
66 LONGEST data_alignment_factor
;
68 /* Return address column. */
69 ULONGEST return_address_register
;
71 /* Instruction sequence to initialize a register set. */
72 const gdb_byte
*initial_instructions
;
75 /* Saved augmentation, in case it's needed later. */
78 /* Encoding of addresses. */
81 /* Target address size in bytes. */
84 /* Target pointer size in bytes. */
87 /* True if a 'z' augmentation existed. */
88 unsigned char saw_z_augmentation
;
90 /* True if an 'S' augmentation existed. */
91 unsigned char signal_frame
;
93 /* The version recorded in the CIE. */
94 unsigned char version
;
96 /* The segment size. */
97 unsigned char segment_size
;
100 struct dwarf2_cie_table
103 struct dwarf2_cie
**entries
;
106 /* Frame Description Entry (FDE). */
110 /* CIE for this FDE. */
111 struct dwarf2_cie
*cie
;
113 /* First location associated with this FDE. */
114 CORE_ADDR initial_location
;
116 /* Number of bytes of program instructions described by this FDE. */
117 CORE_ADDR address_range
;
119 /* Instruction sequence. */
120 const gdb_byte
*instructions
;
123 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
125 unsigned char eh_frame_p
;
128 struct dwarf2_fde_table
131 struct dwarf2_fde
**entries
;
134 /* A minimal decoding of DWARF2 compilation units. We only decode
135 what's needed to get to the call frame information. */
139 /* Keep the bfd convenient. */
142 struct objfile
*objfile
;
144 /* Pointer to the .debug_frame section loaded into memory. */
145 const gdb_byte
*dwarf_frame_buffer
;
147 /* Length of the loaded .debug_frame section. */
148 bfd_size_type dwarf_frame_size
;
150 /* Pointer to the .debug_frame section. */
151 asection
*dwarf_frame_section
;
153 /* Base for DW_EH_PE_datarel encodings. */
156 /* Base for DW_EH_PE_textrel encodings. */
160 static struct dwarf2_fde
*dwarf2_frame_find_fde (CORE_ADDR
*pc
,
161 CORE_ADDR
*out_offset
);
163 static int dwarf2_frame_adjust_regnum (struct gdbarch
*gdbarch
, int regnum
,
166 static CORE_ADDR
read_encoded_value (struct comp_unit
*unit
, gdb_byte encoding
,
167 int ptr_len
, const gdb_byte
*buf
,
168 unsigned int *bytes_read_ptr
,
169 CORE_ADDR func_base
);
172 /* Store the length the expression for the CFA in the `cfa_reg' field,
173 which is unused in that case. */
174 #define cfa_exp_len cfa_reg
176 dwarf2_frame_state::dwarf2_frame_state (CORE_ADDR pc_
, struct dwarf2_cie
*cie
)
177 : pc (pc_
), data_align (cie
->data_alignment_factor
),
178 code_align (cie
->code_alignment_factor
),
179 retaddr_column (cie
->return_address_register
)
184 /* Helper functions for execute_stack_op. */
187 read_addr_from_reg (struct frame_info
*this_frame
, int reg
)
189 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
190 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, reg
);
192 return address_from_register (regnum
, this_frame
);
195 /* Execute the required actions for both the DW_CFA_restore and
196 DW_CFA_restore_extended instructions. */
198 dwarf2_restore_rule (struct gdbarch
*gdbarch
, ULONGEST reg_num
,
199 struct dwarf2_frame_state
*fs
, int eh_frame_p
)
203 gdb_assert (fs
->initial
.reg
);
204 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg_num
, eh_frame_p
);
205 fs
->regs
.alloc_regs (reg
+ 1);
207 /* Check if this register was explicitly initialized in the
208 CIE initial instructions. If not, default the rule to
210 if (reg
< fs
->initial
.num_regs
)
211 fs
->regs
.reg
[reg
] = fs
->initial
.reg
[reg
];
213 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNSPECIFIED
;
215 if (fs
->regs
.reg
[reg
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
217 int regnum
= dwarf_reg_to_regnum (gdbarch
, reg
);
219 complaint (&symfile_complaints
, _("\
220 incomplete CFI data; DW_CFA_restore unspecified\n\
221 register %s (#%d) at %s"),
222 gdbarch_register_name (gdbarch
, regnum
), regnum
,
223 paddress (gdbarch
, fs
->pc
));
227 class dwarf_expr_executor
: public dwarf_expr_context
231 struct frame_info
*this_frame
;
233 CORE_ADDR
read_addr_from_reg (int reg
) OVERRIDE
235 return ::read_addr_from_reg (this_frame
, reg
);
238 struct value
*get_reg_value (struct type
*type
, int reg
) OVERRIDE
240 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
241 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, reg
);
243 return value_from_register (type
, regnum
, this_frame
);
246 void read_mem (gdb_byte
*buf
, CORE_ADDR addr
, size_t len
) OVERRIDE
248 read_memory (addr
, buf
, len
);
251 void get_frame_base (const gdb_byte
**start
, size_t *length
) OVERRIDE
253 invalid ("DW_OP_fbreg");
256 void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind
,
257 union call_site_parameter_u kind_u
,
258 int deref_size
) OVERRIDE
260 invalid ("DW_OP_entry_value");
263 CORE_ADDR
get_object_address () OVERRIDE
265 invalid ("DW_OP_push_object_address");
268 CORE_ADDR
get_frame_cfa () OVERRIDE
270 invalid ("DW_OP_call_frame_cfa");
273 CORE_ADDR
get_tls_address (CORE_ADDR offset
) OVERRIDE
275 invalid ("DW_OP_form_tls_address");
278 void dwarf_call (cu_offset die_offset
) OVERRIDE
280 invalid ("DW_OP_call*");
283 CORE_ADDR
get_addr_index (unsigned int index
)
285 invalid ("DW_OP_GNU_addr_index");
290 void invalid (const char *op
) ATTRIBUTE_NORETURN
292 error (_("%s is invalid in this context"), op
);
297 execute_stack_op (const gdb_byte
*exp
, ULONGEST len
, int addr_size
,
298 CORE_ADDR offset
, struct frame_info
*this_frame
,
299 CORE_ADDR initial
, int initial_in_stack_memory
)
303 dwarf_expr_executor ctx
;
304 scoped_value_mark free_values
;
306 ctx
.this_frame
= this_frame
;
307 ctx
.gdbarch
= get_frame_arch (this_frame
);
308 ctx
.addr_size
= addr_size
;
309 ctx
.ref_addr_size
= -1;
312 ctx
.push_address (initial
, initial_in_stack_memory
);
315 if (ctx
.location
== DWARF_VALUE_MEMORY
)
316 result
= ctx
.fetch_address (0);
317 else if (ctx
.location
== DWARF_VALUE_REGISTER
)
318 result
= ctx
.read_addr_from_reg (value_as_long (ctx
.fetch (0)));
321 /* This is actually invalid DWARF, but if we ever do run across
322 it somehow, we might as well support it. So, instead, report
323 it as unimplemented. */
325 Not implemented: computing unwound register using explicit value operator"));
332 /* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior
333 PC. Modify FS state accordingly. Return current INSN_PTR where the
334 execution has stopped, one can resume it on the next call. */
336 static const gdb_byte
*
337 execute_cfa_program (struct dwarf2_fde
*fde
, const gdb_byte
*insn_ptr
,
338 const gdb_byte
*insn_end
, struct gdbarch
*gdbarch
,
339 CORE_ADDR pc
, struct dwarf2_frame_state
*fs
)
341 int eh_frame_p
= fde
->eh_frame_p
;
342 unsigned int bytes_read
;
343 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
345 while (insn_ptr
< insn_end
&& fs
->pc
<= pc
)
347 gdb_byte insn
= *insn_ptr
++;
351 if ((insn
& 0xc0) == DW_CFA_advance_loc
)
352 fs
->pc
+= (insn
& 0x3f) * fs
->code_align
;
353 else if ((insn
& 0xc0) == DW_CFA_offset
)
356 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
357 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
358 offset
= utmp
* fs
->data_align
;
359 fs
->regs
.alloc_regs (reg
+ 1);
360 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
361 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
363 else if ((insn
& 0xc0) == DW_CFA_restore
)
366 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
373 fs
->pc
= read_encoded_value (fde
->cie
->unit
, fde
->cie
->encoding
,
374 fde
->cie
->ptr_size
, insn_ptr
,
375 &bytes_read
, fde
->initial_location
);
376 /* Apply the objfile offset for relocatable objects. */
377 fs
->pc
+= ANOFFSET (fde
->cie
->unit
->objfile
->section_offsets
,
378 SECT_OFF_TEXT (fde
->cie
->unit
->objfile
));
379 insn_ptr
+= bytes_read
;
382 case DW_CFA_advance_loc1
:
383 utmp
= extract_unsigned_integer (insn_ptr
, 1, byte_order
);
384 fs
->pc
+= utmp
* fs
->code_align
;
387 case DW_CFA_advance_loc2
:
388 utmp
= extract_unsigned_integer (insn_ptr
, 2, byte_order
);
389 fs
->pc
+= utmp
* fs
->code_align
;
392 case DW_CFA_advance_loc4
:
393 utmp
= extract_unsigned_integer (insn_ptr
, 4, byte_order
);
394 fs
->pc
+= utmp
* fs
->code_align
;
398 case DW_CFA_offset_extended
:
399 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
400 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
401 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
402 offset
= utmp
* fs
->data_align
;
403 fs
->regs
.alloc_regs (reg
+ 1);
404 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
405 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
408 case DW_CFA_restore_extended
:
409 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
410 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
413 case DW_CFA_undefined
:
414 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
415 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
416 fs
->regs
.alloc_regs (reg
+ 1);
417 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNDEFINED
;
420 case DW_CFA_same_value
:
421 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
422 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
423 fs
->regs
.alloc_regs (reg
+ 1);
424 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAME_VALUE
;
427 case DW_CFA_register
:
428 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
429 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
430 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
431 utmp
= dwarf2_frame_adjust_regnum (gdbarch
, utmp
, eh_frame_p
);
432 fs
->regs
.alloc_regs (reg
+ 1);
433 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_REG
;
434 fs
->regs
.reg
[reg
].loc
.reg
= utmp
;
437 case DW_CFA_remember_state
:
439 struct dwarf2_frame_state_reg_info
*new_rs
;
441 new_rs
= new dwarf2_frame_state_reg_info (fs
->regs
);
442 fs
->regs
.prev
= new_rs
;
446 case DW_CFA_restore_state
:
448 struct dwarf2_frame_state_reg_info
*old_rs
= fs
->regs
.prev
;
452 complaint (&symfile_complaints
, _("\
453 bad CFI data; mismatched DW_CFA_restore_state at %s"),
454 paddress (gdbarch
, fs
->pc
));
457 fs
->regs
= std::move (*old_rs
);
462 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
463 fs
->regs
.cfa_reg
= reg
;
464 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
466 if (fs
->armcc_cfa_offsets_sf
)
467 utmp
*= fs
->data_align
;
469 fs
->regs
.cfa_offset
= utmp
;
470 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
473 case DW_CFA_def_cfa_register
:
474 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
475 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
,
477 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
480 case DW_CFA_def_cfa_offset
:
481 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
483 if (fs
->armcc_cfa_offsets_sf
)
484 utmp
*= fs
->data_align
;
486 fs
->regs
.cfa_offset
= utmp
;
487 /* cfa_how deliberately not set. */
493 case DW_CFA_def_cfa_expression
:
494 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
495 fs
->regs
.cfa_exp_len
= utmp
;
496 fs
->regs
.cfa_exp
= insn_ptr
;
497 fs
->regs
.cfa_how
= CFA_EXP
;
498 insn_ptr
+= fs
->regs
.cfa_exp_len
;
501 case DW_CFA_expression
:
502 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
503 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
504 fs
->regs
.alloc_regs (reg
+ 1);
505 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
506 fs
->regs
.reg
[reg
].loc
.exp
.start
= insn_ptr
;
507 fs
->regs
.reg
[reg
].loc
.exp
.len
= utmp
;
508 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_EXP
;
512 case DW_CFA_offset_extended_sf
:
513 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
514 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
515 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
516 offset
*= fs
->data_align
;
517 fs
->regs
.alloc_regs (reg
+ 1);
518 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
519 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
522 case DW_CFA_val_offset
:
523 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
524 fs
->regs
.alloc_regs (reg
+ 1);
525 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
526 offset
= utmp
* fs
->data_align
;
527 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_OFFSET
;
528 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
531 case DW_CFA_val_offset_sf
:
532 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
533 fs
->regs
.alloc_regs (reg
+ 1);
534 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
535 offset
*= fs
->data_align
;
536 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_OFFSET
;
537 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
540 case DW_CFA_val_expression
:
541 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
542 fs
->regs
.alloc_regs (reg
+ 1);
543 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
544 fs
->regs
.reg
[reg
].loc
.exp
.start
= insn_ptr
;
545 fs
->regs
.reg
[reg
].loc
.exp
.len
= utmp
;
546 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_EXP
;
550 case DW_CFA_def_cfa_sf
:
551 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
552 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
,
554 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
555 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
556 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
559 case DW_CFA_def_cfa_offset_sf
:
560 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
561 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
562 /* cfa_how deliberately not set. */
565 case DW_CFA_GNU_args_size
:
567 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
570 case DW_CFA_GNU_negative_offset_extended
:
571 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
572 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
573 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
574 offset
= utmp
* fs
->data_align
;
575 fs
->regs
.alloc_regs (reg
+ 1);
576 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
577 fs
->regs
.reg
[reg
].loc
.offset
= -offset
;
581 if (insn
>= DW_CFA_lo_user
&& insn
<= DW_CFA_hi_user
)
583 /* Handle vendor-specific CFI for different architectures. */
584 if (!gdbarch_execute_dwarf_cfa_vendor_op (gdbarch
, insn
, fs
))
585 error (_("Call Frame Instruction op %d in vendor extension "
586 "space is not handled on this architecture."),
590 internal_error (__FILE__
, __LINE__
,
591 _("Unknown CFI encountered."));
596 if (fs
->initial
.reg
== NULL
)
598 /* Don't allow remember/restore between CIE and FDE programs. */
599 delete fs
->regs
.prev
;
600 fs
->regs
.prev
= NULL
;
608 namespace selftests
{
610 /* Unit test to function execute_cfa_program. */
613 execute_cfa_program_test (struct gdbarch
*gdbarch
)
615 struct dwarf2_fde fde
;
616 struct dwarf2_cie cie
;
618 memset (&fde
, 0, sizeof fde
);
619 memset (&cie
, 0, sizeof cie
);
621 cie
.data_alignment_factor
= -4;
622 cie
.code_alignment_factor
= 2;
625 dwarf2_frame_state
fs (0, fde
.cie
);
629 DW_CFA_def_cfa
, 1, 4, /* DW_CFA_def_cfa: r1 ofs 4 */
630 DW_CFA_offset
| 0x2, 1, /* DW_CFA_offset: r2 at cfa-4 */
631 DW_CFA_remember_state
,
632 DW_CFA_restore_state
,
635 const gdb_byte
*insn_end
= insns
+ sizeof (insns
);
636 const gdb_byte
*out
= execute_cfa_program (&fde
, insns
, insn_end
, gdbarch
,
639 SELF_CHECK (out
== insn_end
);
640 SELF_CHECK (fs
.pc
== 0);
642 /* The instructions above only use r1 and r2, but the register numbers
643 used are adjusted by dwarf2_frame_adjust_regnum. */
644 auto r1
= dwarf2_frame_adjust_regnum (gdbarch
, 1, fde
.eh_frame_p
);
645 auto r2
= dwarf2_frame_adjust_regnum (gdbarch
, 2, fde
.eh_frame_p
);
647 SELF_CHECK (fs
.regs
.num_regs
== (std::max (r1
, r2
) + 1));
649 SELF_CHECK (fs
.regs
.reg
[r2
].how
== DWARF2_FRAME_REG_SAVED_OFFSET
);
650 SELF_CHECK (fs
.regs
.reg
[r2
].loc
.offset
== -4);
652 for (auto i
= 0; i
< fs
.regs
.num_regs
; i
++)
654 SELF_CHECK (fs
.regs
.reg
[i
].how
== DWARF2_FRAME_REG_UNSPECIFIED
);
656 SELF_CHECK (fs
.regs
.cfa_reg
== 1);
657 SELF_CHECK (fs
.regs
.cfa_offset
== 4);
658 SELF_CHECK (fs
.regs
.cfa_how
== CFA_REG_OFFSET
);
659 SELF_CHECK (fs
.regs
.cfa_exp
== NULL
);
660 SELF_CHECK (fs
.regs
.prev
== NULL
);
663 } // namespace selftests
664 #endif /* GDB_SELF_TEST */
668 /* Architecture-specific operations. */
670 /* Per-architecture data key. */
671 static struct gdbarch_data
*dwarf2_frame_data
;
673 struct dwarf2_frame_ops
675 /* Pre-initialize the register state REG for register REGNUM. */
676 void (*init_reg
) (struct gdbarch
*, int, struct dwarf2_frame_state_reg
*,
677 struct frame_info
*);
679 /* Check whether the THIS_FRAME is a signal trampoline. */
680 int (*signal_frame_p
) (struct gdbarch
*, struct frame_info
*);
682 /* Convert .eh_frame register number to DWARF register number, or
683 adjust .debug_frame register number. */
684 int (*adjust_regnum
) (struct gdbarch
*, int, int);
687 /* Default architecture-specific register state initialization
691 dwarf2_frame_default_init_reg (struct gdbarch
*gdbarch
, int regnum
,
692 struct dwarf2_frame_state_reg
*reg
,
693 struct frame_info
*this_frame
)
695 /* If we have a register that acts as a program counter, mark it as
696 a destination for the return address. If we have a register that
697 serves as the stack pointer, arrange for it to be filled with the
698 call frame address (CFA). The other registers are marked as
701 We copy the return address to the program counter, since many
702 parts in GDB assume that it is possible to get the return address
703 by unwinding the program counter register. However, on ISA's
704 with a dedicated return address register, the CFI usually only
705 contains information to unwind that return address register.
707 The reason we're treating the stack pointer special here is
708 because in many cases GCC doesn't emit CFI for the stack pointer
709 and implicitly assumes that it is equal to the CFA. This makes
710 some sense since the DWARF specification (version 3, draft 8,
713 "Typically, the CFA is defined to be the value of the stack
714 pointer at the call site in the previous frame (which may be
715 different from its value on entry to the current frame)."
717 However, this isn't true for all platforms supported by GCC
718 (e.g. IBM S/390 and zSeries). Those architectures should provide
719 their own architecture-specific initialization function. */
721 if (regnum
== gdbarch_pc_regnum (gdbarch
))
722 reg
->how
= DWARF2_FRAME_REG_RA
;
723 else if (regnum
== gdbarch_sp_regnum (gdbarch
))
724 reg
->how
= DWARF2_FRAME_REG_CFA
;
727 /* Return a default for the architecture-specific operations. */
730 dwarf2_frame_init (struct obstack
*obstack
)
732 struct dwarf2_frame_ops
*ops
;
734 ops
= OBSTACK_ZALLOC (obstack
, struct dwarf2_frame_ops
);
735 ops
->init_reg
= dwarf2_frame_default_init_reg
;
739 /* Set the architecture-specific register state initialization
740 function for GDBARCH to INIT_REG. */
743 dwarf2_frame_set_init_reg (struct gdbarch
*gdbarch
,
744 void (*init_reg
) (struct gdbarch
*, int,
745 struct dwarf2_frame_state_reg
*,
746 struct frame_info
*))
748 struct dwarf2_frame_ops
*ops
749 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
751 ops
->init_reg
= init_reg
;
754 /* Pre-initialize the register state REG for register REGNUM. */
757 dwarf2_frame_init_reg (struct gdbarch
*gdbarch
, int regnum
,
758 struct dwarf2_frame_state_reg
*reg
,
759 struct frame_info
*this_frame
)
761 struct dwarf2_frame_ops
*ops
762 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
764 ops
->init_reg (gdbarch
, regnum
, reg
, this_frame
);
767 /* Set the architecture-specific signal trampoline recognition
768 function for GDBARCH to SIGNAL_FRAME_P. */
771 dwarf2_frame_set_signal_frame_p (struct gdbarch
*gdbarch
,
772 int (*signal_frame_p
) (struct gdbarch
*,
773 struct frame_info
*))
775 struct dwarf2_frame_ops
*ops
776 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
778 ops
->signal_frame_p
= signal_frame_p
;
781 /* Query the architecture-specific signal frame recognizer for
785 dwarf2_frame_signal_frame_p (struct gdbarch
*gdbarch
,
786 struct frame_info
*this_frame
)
788 struct dwarf2_frame_ops
*ops
789 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
791 if (ops
->signal_frame_p
== NULL
)
793 return ops
->signal_frame_p (gdbarch
, this_frame
);
796 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
800 dwarf2_frame_set_adjust_regnum (struct gdbarch
*gdbarch
,
801 int (*adjust_regnum
) (struct gdbarch
*,
804 struct dwarf2_frame_ops
*ops
805 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
807 ops
->adjust_regnum
= adjust_regnum
;
810 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
814 dwarf2_frame_adjust_regnum (struct gdbarch
*gdbarch
,
815 int regnum
, int eh_frame_p
)
817 struct dwarf2_frame_ops
*ops
818 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
820 if (ops
->adjust_regnum
== NULL
)
822 return ops
->adjust_regnum (gdbarch
, regnum
, eh_frame_p
);
826 dwarf2_frame_find_quirks (struct dwarf2_frame_state
*fs
,
827 struct dwarf2_fde
*fde
)
829 struct compunit_symtab
*cust
;
831 cust
= find_pc_compunit_symtab (fs
->pc
);
835 if (producer_is_realview (COMPUNIT_PRODUCER (cust
)))
837 if (fde
->cie
->version
== 1)
838 fs
->armcc_cfa_offsets_sf
= 1;
840 if (fde
->cie
->version
== 1)
841 fs
->armcc_cfa_offsets_reversed
= 1;
843 /* The reversed offset problem is present in some compilers
844 using DWARF3, but it was eventually fixed. Check the ARM
845 defined augmentations, which are in the format "armcc" followed
846 by a list of one-character options. The "+" option means
847 this problem is fixed (no quirk needed). If the armcc
848 augmentation is missing, the quirk is needed. */
849 if (fde
->cie
->version
== 3
850 && (!startswith (fde
->cie
->augmentation
, "armcc")
851 || strchr (fde
->cie
->augmentation
+ 5, '+') == NULL
))
852 fs
->armcc_cfa_offsets_reversed
= 1;
859 /* See dwarf2-frame.h. */
862 dwarf2_fetch_cfa_info (struct gdbarch
*gdbarch
, CORE_ADDR pc
,
863 struct dwarf2_per_cu_data
*data
,
864 int *regnum_out
, LONGEST
*offset_out
,
865 CORE_ADDR
*text_offset_out
,
866 const gdb_byte
**cfa_start_out
,
867 const gdb_byte
**cfa_end_out
)
869 struct dwarf2_fde
*fde
;
870 CORE_ADDR text_offset
;
873 /* Find the correct FDE. */
874 fde
= dwarf2_frame_find_fde (&pc1
, &text_offset
);
876 error (_("Could not compute CFA; needed to translate this expression"));
878 dwarf2_frame_state
fs (pc1
, fde
->cie
);
880 /* Check for "quirks" - known bugs in producers. */
881 dwarf2_frame_find_quirks (&fs
, fde
);
883 /* First decode all the insns in the CIE. */
884 execute_cfa_program (fde
, fde
->cie
->initial_instructions
,
885 fde
->cie
->end
, gdbarch
, pc
, &fs
);
887 /* Save the initialized register set. */
888 fs
.initial
= fs
.regs
;
890 /* Then decode the insns in the FDE up to our target PC. */
891 execute_cfa_program (fde
, fde
->instructions
, fde
->end
, gdbarch
, pc
, &fs
);
893 /* Calculate the CFA. */
894 switch (fs
.regs
.cfa_how
)
898 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, fs
.regs
.cfa_reg
);
900 *regnum_out
= regnum
;
901 if (fs
.armcc_cfa_offsets_reversed
)
902 *offset_out
= -fs
.regs
.cfa_offset
;
904 *offset_out
= fs
.regs
.cfa_offset
;
909 *text_offset_out
= text_offset
;
910 *cfa_start_out
= fs
.regs
.cfa_exp
;
911 *cfa_end_out
= fs
.regs
.cfa_exp
+ fs
.regs
.cfa_exp_len
;
915 internal_error (__FILE__
, __LINE__
, _("Unknown CFA rule."));
920 struct dwarf2_frame_cache
922 /* DWARF Call Frame Address. */
925 /* Set if the return address column was marked as unavailable
926 (required non-collected memory or registers to compute). */
927 int unavailable_retaddr
;
929 /* Set if the return address column was marked as undefined. */
930 int undefined_retaddr
;
932 /* Saved registers, indexed by GDB register number, not by DWARF
934 struct dwarf2_frame_state_reg
*reg
;
936 /* Return address register. */
937 struct dwarf2_frame_state_reg retaddr_reg
;
939 /* Target address size in bytes. */
942 /* The .text offset. */
943 CORE_ADDR text_offset
;
945 /* True if we already checked whether this frame is the bottom frame
946 of a virtual tail call frame chain. */
947 int checked_tailcall_bottom
;
949 /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME
950 sequence. If NULL then it is a normal case with no TAILCALL_FRAME
951 involved. Non-bottom frames of a virtual tail call frames chain use
952 dwarf2_tailcall_frame_unwind unwinder so this field does not apply for
954 void *tailcall_cache
;
956 /* The number of bytes to subtract from TAILCALL_FRAME frames frame
957 base to get the SP, to simulate the return address pushed on the
959 LONGEST entry_cfa_sp_offset
;
960 int entry_cfa_sp_offset_p
;
963 /* A cleanup that sets a pointer to NULL. */
966 clear_pointer_cleanup (void *arg
)
968 void **ptr
= (void **) arg
;
973 static struct dwarf2_frame_cache
*
974 dwarf2_frame_cache (struct frame_info
*this_frame
, void **this_cache
)
976 struct cleanup
*reset_cache_cleanup
;
977 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
978 const int num_regs
= gdbarch_num_regs (gdbarch
)
979 + gdbarch_num_pseudo_regs (gdbarch
);
980 struct dwarf2_frame_cache
*cache
;
981 struct dwarf2_fde
*fde
;
983 const gdb_byte
*instr
;
986 return (struct dwarf2_frame_cache
*) *this_cache
;
988 /* Allocate a new cache. */
989 cache
= FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache
);
990 cache
->reg
= FRAME_OBSTACK_CALLOC (num_regs
, struct dwarf2_frame_state_reg
);
992 reset_cache_cleanup
= make_cleanup (clear_pointer_cleanup
, this_cache
);
996 Note that if the next frame is never supposed to return (i.e. a call
997 to abort), the compiler might optimize away the instruction at
998 its return address. As a result the return address will
999 point at some random instruction, and the CFI for that
1000 instruction is probably worthless to us. GCC's unwinder solves
1001 this problem by substracting 1 from the return address to get an
1002 address in the middle of a presumed call instruction (or the
1003 instruction in the associated delay slot). This should only be
1004 done for "normal" frames and not for resume-type frames (signal
1005 handlers, sentinel frames, dummy frames). The function
1006 get_frame_address_in_block does just this. It's not clear how
1007 reliable the method is though; there is the potential for the
1008 register state pre-call being different to that on return. */
1009 CORE_ADDR pc1
= get_frame_address_in_block (this_frame
);
1011 /* Find the correct FDE. */
1012 fde
= dwarf2_frame_find_fde (&pc1
, &cache
->text_offset
);
1013 gdb_assert (fde
!= NULL
);
1015 /* Allocate and initialize the frame state. */
1016 struct dwarf2_frame_state
fs (pc1
, fde
->cie
);
1018 cache
->addr_size
= fde
->cie
->addr_size
;
1020 /* Check for "quirks" - known bugs in producers. */
1021 dwarf2_frame_find_quirks (&fs
, fde
);
1023 /* First decode all the insns in the CIE. */
1024 execute_cfa_program (fde
, fde
->cie
->initial_instructions
,
1025 fde
->cie
->end
, gdbarch
,
1026 get_frame_address_in_block (this_frame
), &fs
);
1028 /* Save the initialized register set. */
1029 fs
.initial
= fs
.regs
;
1031 if (get_frame_func_if_available (this_frame
, &entry_pc
))
1033 /* Decode the insns in the FDE up to the entry PC. */
1034 instr
= execute_cfa_program (fde
, fde
->instructions
, fde
->end
, gdbarch
,
1037 if (fs
.regs
.cfa_how
== CFA_REG_OFFSET
1038 && (dwarf_reg_to_regnum (gdbarch
, fs
.regs
.cfa_reg
)
1039 == gdbarch_sp_regnum (gdbarch
)))
1041 cache
->entry_cfa_sp_offset
= fs
.regs
.cfa_offset
;
1042 cache
->entry_cfa_sp_offset_p
= 1;
1046 instr
= fde
->instructions
;
1048 /* Then decode the insns in the FDE up to our target PC. */
1049 execute_cfa_program (fde
, instr
, fde
->end
, gdbarch
,
1050 get_frame_address_in_block (this_frame
), &fs
);
1054 /* Calculate the CFA. */
1055 switch (fs
.regs
.cfa_how
)
1057 case CFA_REG_OFFSET
:
1058 cache
->cfa
= read_addr_from_reg (this_frame
, fs
.regs
.cfa_reg
);
1059 if (fs
.armcc_cfa_offsets_reversed
)
1060 cache
->cfa
-= fs
.regs
.cfa_offset
;
1062 cache
->cfa
+= fs
.regs
.cfa_offset
;
1067 execute_stack_op (fs
.regs
.cfa_exp
, fs
.regs
.cfa_exp_len
,
1068 cache
->addr_size
, cache
->text_offset
,
1073 internal_error (__FILE__
, __LINE__
, _("Unknown CFA rule."));
1076 CATCH (ex
, RETURN_MASK_ERROR
)
1078 if (ex
.error
== NOT_AVAILABLE_ERROR
)
1080 cache
->unavailable_retaddr
= 1;
1081 discard_cleanups (reset_cache_cleanup
);
1085 throw_exception (ex
);
1089 /* Initialize the register state. */
1093 for (regnum
= 0; regnum
< num_regs
; regnum
++)
1094 dwarf2_frame_init_reg (gdbarch
, regnum
, &cache
->reg
[regnum
], this_frame
);
1097 /* Go through the DWARF2 CFI generated table and save its register
1098 location information in the cache. Note that we don't skip the
1099 return address column; it's perfectly all right for it to
1100 correspond to a real register. */
1102 int column
; /* CFI speak for "register number". */
1104 for (column
= 0; column
< fs
.regs
.num_regs
; column
++)
1106 /* Use the GDB register number as the destination index. */
1107 int regnum
= dwarf_reg_to_regnum (gdbarch
, column
);
1109 /* Protect against a target returning a bad register. */
1110 if (regnum
< 0 || regnum
>= num_regs
)
1113 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1114 of all debug info registers. If it doesn't, complain (but
1115 not too loudly). It turns out that GCC assumes that an
1116 unspecified register implies "same value" when CFI (draft
1117 7) specifies nothing at all. Such a register could equally
1118 be interpreted as "undefined". Also note that this check
1119 isn't sufficient; it only checks that all registers in the
1120 range [0 .. max column] are specified, and won't detect
1121 problems when a debug info register falls outside of the
1122 table. We need a way of iterating through all the valid
1123 DWARF2 register numbers. */
1124 if (fs
.regs
.reg
[column
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
1126 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
1127 complaint (&symfile_complaints
, _("\
1128 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1129 gdbarch_register_name (gdbarch
, regnum
),
1130 paddress (gdbarch
, fs
.pc
));
1133 cache
->reg
[regnum
] = fs
.regs
.reg
[column
];
1137 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1138 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1142 for (regnum
= 0; regnum
< num_regs
; regnum
++)
1144 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
1145 || cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA_OFFSET
)
1147 struct dwarf2_frame_state_reg
*retaddr_reg
=
1148 &fs
.regs
.reg
[fs
.retaddr_column
];
1150 /* It seems rather bizarre to specify an "empty" column as
1151 the return adress column. However, this is exactly
1152 what GCC does on some targets. It turns out that GCC
1153 assumes that the return address can be found in the
1154 register corresponding to the return address column.
1155 Incidentally, that's how we should treat a return
1156 address column specifying "same value" too. */
1157 if (fs
.retaddr_column
< fs
.regs
.num_regs
1158 && retaddr_reg
->how
!= DWARF2_FRAME_REG_UNSPECIFIED
1159 && retaddr_reg
->how
!= DWARF2_FRAME_REG_SAME_VALUE
)
1161 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1162 cache
->reg
[regnum
] = *retaddr_reg
;
1164 cache
->retaddr_reg
= *retaddr_reg
;
1168 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1170 cache
->reg
[regnum
].loc
.reg
= fs
.retaddr_column
;
1171 cache
->reg
[regnum
].how
= DWARF2_FRAME_REG_SAVED_REG
;
1175 cache
->retaddr_reg
.loc
.reg
= fs
.retaddr_column
;
1176 cache
->retaddr_reg
.how
= DWARF2_FRAME_REG_SAVED_REG
;
1183 if (fs
.retaddr_column
< fs
.regs
.num_regs
1184 && fs
.regs
.reg
[fs
.retaddr_column
].how
== DWARF2_FRAME_REG_UNDEFINED
)
1185 cache
->undefined_retaddr
= 1;
1187 discard_cleanups (reset_cache_cleanup
);
1191 static enum unwind_stop_reason
1192 dwarf2_frame_unwind_stop_reason (struct frame_info
*this_frame
,
1195 struct dwarf2_frame_cache
*cache
1196 = dwarf2_frame_cache (this_frame
, this_cache
);
1198 if (cache
->unavailable_retaddr
)
1199 return UNWIND_UNAVAILABLE
;
1201 if (cache
->undefined_retaddr
)
1202 return UNWIND_OUTERMOST
;
1204 return UNWIND_NO_REASON
;
1208 dwarf2_frame_this_id (struct frame_info
*this_frame
, void **this_cache
,
1209 struct frame_id
*this_id
)
1211 struct dwarf2_frame_cache
*cache
=
1212 dwarf2_frame_cache (this_frame
, this_cache
);
1214 if (cache
->unavailable_retaddr
)
1215 (*this_id
) = frame_id_build_unavailable_stack (get_frame_func (this_frame
));
1216 else if (cache
->undefined_retaddr
)
1219 (*this_id
) = frame_id_build (cache
->cfa
, get_frame_func (this_frame
));
1222 static struct value
*
1223 dwarf2_frame_prev_register (struct frame_info
*this_frame
, void **this_cache
,
1226 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
1227 struct dwarf2_frame_cache
*cache
=
1228 dwarf2_frame_cache (this_frame
, this_cache
);
1232 /* Check whether THIS_FRAME is the bottom frame of a virtual tail
1233 call frame chain. */
1234 if (!cache
->checked_tailcall_bottom
)
1236 cache
->checked_tailcall_bottom
= 1;
1237 dwarf2_tailcall_sniffer_first (this_frame
, &cache
->tailcall_cache
,
1238 (cache
->entry_cfa_sp_offset_p
1239 ? &cache
->entry_cfa_sp_offset
: NULL
));
1242 /* Non-bottom frames of a virtual tail call frames chain use
1243 dwarf2_tailcall_frame_unwind unwinder so this code does not apply for
1244 them. If dwarf2_tailcall_prev_register_first does not have specific value
1245 unwind the register, tail call frames are assumed to have the register set
1246 of the top caller. */
1247 if (cache
->tailcall_cache
)
1251 val
= dwarf2_tailcall_prev_register_first (this_frame
,
1252 &cache
->tailcall_cache
,
1258 switch (cache
->reg
[regnum
].how
)
1260 case DWARF2_FRAME_REG_UNDEFINED
:
1261 /* If CFI explicitly specified that the value isn't defined,
1262 mark it as optimized away; the value isn't available. */
1263 return frame_unwind_got_optimized (this_frame
, regnum
);
1265 case DWARF2_FRAME_REG_SAVED_OFFSET
:
1266 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1267 return frame_unwind_got_memory (this_frame
, regnum
, addr
);
1269 case DWARF2_FRAME_REG_SAVED_REG
:
1270 realnum
= dwarf_reg_to_regnum_or_error
1271 (gdbarch
, cache
->reg
[regnum
].loc
.reg
);
1272 return frame_unwind_got_register (this_frame
, regnum
, realnum
);
1274 case DWARF2_FRAME_REG_SAVED_EXP
:
1275 addr
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
.start
,
1276 cache
->reg
[regnum
].loc
.exp
.len
,
1277 cache
->addr_size
, cache
->text_offset
,
1278 this_frame
, cache
->cfa
, 1);
1279 return frame_unwind_got_memory (this_frame
, regnum
, addr
);
1281 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET
:
1282 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1283 return frame_unwind_got_constant (this_frame
, regnum
, addr
);
1285 case DWARF2_FRAME_REG_SAVED_VAL_EXP
:
1286 addr
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
.start
,
1287 cache
->reg
[regnum
].loc
.exp
.len
,
1288 cache
->addr_size
, cache
->text_offset
,
1289 this_frame
, cache
->cfa
, 1);
1290 return frame_unwind_got_constant (this_frame
, regnum
, addr
);
1292 case DWARF2_FRAME_REG_UNSPECIFIED
:
1293 /* GCC, in its infinite wisdom decided to not provide unwind
1294 information for registers that are "same value". Since
1295 DWARF2 (3 draft 7) doesn't define such behavior, said
1296 registers are actually undefined (which is different to CFI
1297 "undefined"). Code above issues a complaint about this.
1298 Here just fudge the books, assume GCC, and that the value is
1299 more inner on the stack. */
1300 return frame_unwind_got_register (this_frame
, regnum
, regnum
);
1302 case DWARF2_FRAME_REG_SAME_VALUE
:
1303 return frame_unwind_got_register (this_frame
, regnum
, regnum
);
1305 case DWARF2_FRAME_REG_CFA
:
1306 return frame_unwind_got_address (this_frame
, regnum
, cache
->cfa
);
1308 case DWARF2_FRAME_REG_CFA_OFFSET
:
1309 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1310 return frame_unwind_got_address (this_frame
, regnum
, addr
);
1312 case DWARF2_FRAME_REG_RA_OFFSET
:
1313 addr
= cache
->reg
[regnum
].loc
.offset
;
1314 regnum
= dwarf_reg_to_regnum_or_error
1315 (gdbarch
, cache
->retaddr_reg
.loc
.reg
);
1316 addr
+= get_frame_register_unsigned (this_frame
, regnum
);
1317 return frame_unwind_got_address (this_frame
, regnum
, addr
);
1319 case DWARF2_FRAME_REG_FN
:
1320 return cache
->reg
[regnum
].loc
.fn (this_frame
, this_cache
, regnum
);
1323 internal_error (__FILE__
, __LINE__
, _("Unknown register rule."));
1327 /* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail
1328 call frames chain. */
1331 dwarf2_frame_dealloc_cache (struct frame_info
*self
, void *this_cache
)
1333 struct dwarf2_frame_cache
*cache
= dwarf2_frame_cache (self
, &this_cache
);
1335 if (cache
->tailcall_cache
)
1336 dwarf2_tailcall_frame_unwind
.dealloc_cache (self
, cache
->tailcall_cache
);
1340 dwarf2_frame_sniffer (const struct frame_unwind
*self
,
1341 struct frame_info
*this_frame
, void **this_cache
)
1343 /* Grab an address that is guarenteed to reside somewhere within the
1344 function. get_frame_pc(), with a no-return next function, can
1345 end up returning something past the end of this function's body.
1346 If the frame we're sniffing for is a signal frame whose start
1347 address is placed on the stack by the OS, its FDE must
1348 extend one byte before its start address or we could potentially
1349 select the FDE of the previous function. */
1350 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1351 struct dwarf2_fde
*fde
= dwarf2_frame_find_fde (&block_addr
, NULL
);
1356 /* On some targets, signal trampolines may have unwind information.
1357 We need to recognize them so that we set the frame type
1360 if (fde
->cie
->signal_frame
1361 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame
),
1363 return self
->type
== SIGTRAMP_FRAME
;
1365 if (self
->type
!= NORMAL_FRAME
)
1371 static const struct frame_unwind dwarf2_frame_unwind
=
1374 dwarf2_frame_unwind_stop_reason
,
1375 dwarf2_frame_this_id
,
1376 dwarf2_frame_prev_register
,
1378 dwarf2_frame_sniffer
,
1379 dwarf2_frame_dealloc_cache
1382 static const struct frame_unwind dwarf2_signal_frame_unwind
=
1385 dwarf2_frame_unwind_stop_reason
,
1386 dwarf2_frame_this_id
,
1387 dwarf2_frame_prev_register
,
1389 dwarf2_frame_sniffer
,
1391 /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */
1395 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1398 dwarf2_append_unwinders (struct gdbarch
*gdbarch
)
1400 /* TAILCALL_FRAME must be first to find the record by
1401 dwarf2_tailcall_sniffer_first. */
1402 frame_unwind_append_unwinder (gdbarch
, &dwarf2_tailcall_frame_unwind
);
1404 frame_unwind_append_unwinder (gdbarch
, &dwarf2_frame_unwind
);
1405 frame_unwind_append_unwinder (gdbarch
, &dwarf2_signal_frame_unwind
);
1409 /* There is no explicitly defined relationship between the CFA and the
1410 location of frame's local variables and arguments/parameters.
1411 Therefore, frame base methods on this page should probably only be
1412 used as a last resort, just to avoid printing total garbage as a
1413 response to the "info frame" command. */
1416 dwarf2_frame_base_address (struct frame_info
*this_frame
, void **this_cache
)
1418 struct dwarf2_frame_cache
*cache
=
1419 dwarf2_frame_cache (this_frame
, this_cache
);
1424 static const struct frame_base dwarf2_frame_base
=
1426 &dwarf2_frame_unwind
,
1427 dwarf2_frame_base_address
,
1428 dwarf2_frame_base_address
,
1429 dwarf2_frame_base_address
1432 const struct frame_base
*
1433 dwarf2_frame_base_sniffer (struct frame_info
*this_frame
)
1435 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1437 if (dwarf2_frame_find_fde (&block_addr
, NULL
))
1438 return &dwarf2_frame_base
;
1443 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1444 the DWARF unwinder. This is used to implement
1445 DW_OP_call_frame_cfa. */
1448 dwarf2_frame_cfa (struct frame_info
*this_frame
)
1450 if (frame_unwinder_is (this_frame
, &record_btrace_tailcall_frame_unwind
)
1451 || frame_unwinder_is (this_frame
, &record_btrace_frame_unwind
))
1452 throw_error (NOT_AVAILABLE_ERROR
,
1453 _("cfa not available for record btrace target"));
1455 while (get_frame_type (this_frame
) == INLINE_FRAME
)
1456 this_frame
= get_prev_frame (this_frame
);
1457 if (get_frame_unwind_stop_reason (this_frame
) == UNWIND_UNAVAILABLE
)
1458 throw_error (NOT_AVAILABLE_ERROR
,
1459 _("can't compute CFA for this frame: "
1460 "required registers or memory are unavailable"));
1462 if (get_frame_id (this_frame
).stack_status
!= FID_STACK_VALID
)
1463 throw_error (NOT_AVAILABLE_ERROR
,
1464 _("can't compute CFA for this frame: "
1465 "frame base not available"));
1467 return get_frame_base (this_frame
);
1470 const struct objfile_data
*dwarf2_frame_objfile_data
;
1473 read_1_byte (bfd
*abfd
, const gdb_byte
*buf
)
1475 return bfd_get_8 (abfd
, buf
);
1479 read_4_bytes (bfd
*abfd
, const gdb_byte
*buf
)
1481 return bfd_get_32 (abfd
, buf
);
1485 read_8_bytes (bfd
*abfd
, const gdb_byte
*buf
)
1487 return bfd_get_64 (abfd
, buf
);
1491 read_initial_length (bfd
*abfd
, const gdb_byte
*buf
,
1492 unsigned int *bytes_read_ptr
)
1496 result
= bfd_get_32 (abfd
, buf
);
1497 if (result
== 0xffffffff)
1499 result
= bfd_get_64 (abfd
, buf
+ 4);
1500 *bytes_read_ptr
= 12;
1503 *bytes_read_ptr
= 4;
1509 /* Pointer encoding helper functions. */
1511 /* GCC supports exception handling based on DWARF2 CFI. However, for
1512 technical reasons, it encodes addresses in its FDE's in a different
1513 way. Several "pointer encodings" are supported. The encoding
1514 that's used for a particular FDE is determined by the 'R'
1515 augmentation in the associated CIE. The argument of this
1516 augmentation is a single byte.
1518 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1519 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1520 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1521 address should be interpreted (absolute, relative to the current
1522 position in the FDE, ...). Bit 7, indicates that the address
1523 should be dereferenced. */
1526 encoding_for_size (unsigned int size
)
1531 return DW_EH_PE_udata2
;
1533 return DW_EH_PE_udata4
;
1535 return DW_EH_PE_udata8
;
1537 internal_error (__FILE__
, __LINE__
, _("Unsupported address size"));
1542 read_encoded_value (struct comp_unit
*unit
, gdb_byte encoding
,
1543 int ptr_len
, const gdb_byte
*buf
,
1544 unsigned int *bytes_read_ptr
,
1545 CORE_ADDR func_base
)
1550 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1552 if (encoding
& DW_EH_PE_indirect
)
1553 internal_error (__FILE__
, __LINE__
,
1554 _("Unsupported encoding: DW_EH_PE_indirect"));
1556 *bytes_read_ptr
= 0;
1558 switch (encoding
& 0x70)
1560 case DW_EH_PE_absptr
:
1563 case DW_EH_PE_pcrel
:
1564 base
= bfd_get_section_vma (unit
->abfd
, unit
->dwarf_frame_section
);
1565 base
+= (buf
- unit
->dwarf_frame_buffer
);
1567 case DW_EH_PE_datarel
:
1570 case DW_EH_PE_textrel
:
1573 case DW_EH_PE_funcrel
:
1576 case DW_EH_PE_aligned
:
1578 offset
= buf
- unit
->dwarf_frame_buffer
;
1579 if ((offset
% ptr_len
) != 0)
1581 *bytes_read_ptr
= ptr_len
- (offset
% ptr_len
);
1582 buf
+= *bytes_read_ptr
;
1586 internal_error (__FILE__
, __LINE__
,
1587 _("Invalid or unsupported encoding"));
1590 if ((encoding
& 0x07) == 0x00)
1592 encoding
|= encoding_for_size (ptr_len
);
1593 if (bfd_get_sign_extend_vma (unit
->abfd
))
1594 encoding
|= DW_EH_PE_signed
;
1597 switch (encoding
& 0x0f)
1599 case DW_EH_PE_uleb128
:
1602 const gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1604 *bytes_read_ptr
+= safe_read_uleb128 (buf
, end_buf
, &value
) - buf
;
1605 return base
+ value
;
1607 case DW_EH_PE_udata2
:
1608 *bytes_read_ptr
+= 2;
1609 return (base
+ bfd_get_16 (unit
->abfd
, (bfd_byte
*) buf
));
1610 case DW_EH_PE_udata4
:
1611 *bytes_read_ptr
+= 4;
1612 return (base
+ bfd_get_32 (unit
->abfd
, (bfd_byte
*) buf
));
1613 case DW_EH_PE_udata8
:
1614 *bytes_read_ptr
+= 8;
1615 return (base
+ bfd_get_64 (unit
->abfd
, (bfd_byte
*) buf
));
1616 case DW_EH_PE_sleb128
:
1619 const gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1621 *bytes_read_ptr
+= safe_read_sleb128 (buf
, end_buf
, &value
) - buf
;
1622 return base
+ value
;
1624 case DW_EH_PE_sdata2
:
1625 *bytes_read_ptr
+= 2;
1626 return (base
+ bfd_get_signed_16 (unit
->abfd
, (bfd_byte
*) buf
));
1627 case DW_EH_PE_sdata4
:
1628 *bytes_read_ptr
+= 4;
1629 return (base
+ bfd_get_signed_32 (unit
->abfd
, (bfd_byte
*) buf
));
1630 case DW_EH_PE_sdata8
:
1631 *bytes_read_ptr
+= 8;
1632 return (base
+ bfd_get_signed_64 (unit
->abfd
, (bfd_byte
*) buf
));
1634 internal_error (__FILE__
, __LINE__
,
1635 _("Invalid or unsupported encoding"));
1641 bsearch_cie_cmp (const void *key
, const void *element
)
1643 ULONGEST cie_pointer
= *(ULONGEST
*) key
;
1644 struct dwarf2_cie
*cie
= *(struct dwarf2_cie
**) element
;
1646 if (cie_pointer
== cie
->cie_pointer
)
1649 return (cie_pointer
< cie
->cie_pointer
) ? -1 : 1;
1652 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1653 static struct dwarf2_cie
*
1654 find_cie (struct dwarf2_cie_table
*cie_table
, ULONGEST cie_pointer
)
1656 struct dwarf2_cie
**p_cie
;
1658 /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
1659 bsearch be non-NULL. */
1660 if (cie_table
->entries
== NULL
)
1662 gdb_assert (cie_table
->num_entries
== 0);
1666 p_cie
= ((struct dwarf2_cie
**)
1667 bsearch (&cie_pointer
, cie_table
->entries
, cie_table
->num_entries
,
1668 sizeof (cie_table
->entries
[0]), bsearch_cie_cmp
));
1674 /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1676 add_cie (struct dwarf2_cie_table
*cie_table
, struct dwarf2_cie
*cie
)
1678 const int n
= cie_table
->num_entries
;
1681 || cie_table
->entries
[n
- 1]->cie_pointer
< cie
->cie_pointer
);
1684 = XRESIZEVEC (struct dwarf2_cie
*, cie_table
->entries
, n
+ 1);
1685 cie_table
->entries
[n
] = cie
;
1686 cie_table
->num_entries
= n
+ 1;
1690 bsearch_fde_cmp (const void *key
, const void *element
)
1692 CORE_ADDR seek_pc
= *(CORE_ADDR
*) key
;
1693 struct dwarf2_fde
*fde
= *(struct dwarf2_fde
**) element
;
1695 if (seek_pc
< fde
->initial_location
)
1697 if (seek_pc
< fde
->initial_location
+ fde
->address_range
)
1702 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1703 inital location associated with it into *PC. */
1705 static struct dwarf2_fde
*
1706 dwarf2_frame_find_fde (CORE_ADDR
*pc
, CORE_ADDR
*out_offset
)
1708 struct objfile
*objfile
;
1710 ALL_OBJFILES (objfile
)
1712 struct dwarf2_fde_table
*fde_table
;
1713 struct dwarf2_fde
**p_fde
;
1717 fde_table
= ((struct dwarf2_fde_table
*)
1718 objfile_data (objfile
, dwarf2_frame_objfile_data
));
1719 if (fde_table
== NULL
)
1721 dwarf2_build_frame_info (objfile
);
1722 fde_table
= ((struct dwarf2_fde_table
*)
1723 objfile_data (objfile
, dwarf2_frame_objfile_data
));
1725 gdb_assert (fde_table
!= NULL
);
1727 if (fde_table
->num_entries
== 0)
1730 gdb_assert (objfile
->section_offsets
);
1731 offset
= ANOFFSET (objfile
->section_offsets
, SECT_OFF_TEXT (objfile
));
1733 gdb_assert (fde_table
->num_entries
> 0);
1734 if (*pc
< offset
+ fde_table
->entries
[0]->initial_location
)
1737 seek_pc
= *pc
- offset
;
1738 p_fde
= ((struct dwarf2_fde
**)
1739 bsearch (&seek_pc
, fde_table
->entries
, fde_table
->num_entries
,
1740 sizeof (fde_table
->entries
[0]), bsearch_fde_cmp
));
1743 *pc
= (*p_fde
)->initial_location
+ offset
;
1745 *out_offset
= offset
;
1752 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1754 add_fde (struct dwarf2_fde_table
*fde_table
, struct dwarf2_fde
*fde
)
1756 if (fde
->address_range
== 0)
1757 /* Discard useless FDEs. */
1760 fde_table
->num_entries
+= 1;
1761 fde_table
->entries
= XRESIZEVEC (struct dwarf2_fde
*, fde_table
->entries
,
1762 fde_table
->num_entries
);
1763 fde_table
->entries
[fde_table
->num_entries
- 1] = fde
;
1766 #define DW64_CIE_ID 0xffffffffffffffffULL
1768 /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
1773 EH_CIE_TYPE_ID
= 1 << 0,
1774 EH_FDE_TYPE_ID
= 1 << 1,
1775 EH_CIE_OR_FDE_TYPE_ID
= EH_CIE_TYPE_ID
| EH_FDE_TYPE_ID
1778 static const gdb_byte
*decode_frame_entry (struct comp_unit
*unit
,
1779 const gdb_byte
*start
,
1781 struct dwarf2_cie_table
*cie_table
,
1782 struct dwarf2_fde_table
*fde_table
,
1783 enum eh_frame_type entry_type
);
1785 /* Decode the next CIE or FDE, entry_type specifies the expected type.
1786 Return NULL if invalid input, otherwise the next byte to be processed. */
1788 static const gdb_byte
*
1789 decode_frame_entry_1 (struct comp_unit
*unit
, const gdb_byte
*start
,
1791 struct dwarf2_cie_table
*cie_table
,
1792 struct dwarf2_fde_table
*fde_table
,
1793 enum eh_frame_type entry_type
)
1795 struct gdbarch
*gdbarch
= get_objfile_arch (unit
->objfile
);
1796 const gdb_byte
*buf
, *end
;
1798 unsigned int bytes_read
;
1801 ULONGEST cie_pointer
;
1806 length
= read_initial_length (unit
->abfd
, buf
, &bytes_read
);
1810 /* Are we still within the section? */
1811 if (end
> unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
1817 /* Distinguish between 32 and 64-bit encoded frame info. */
1818 dwarf64_p
= (bytes_read
== 12);
1820 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1824 cie_id
= DW64_CIE_ID
;
1830 cie_pointer
= read_8_bytes (unit
->abfd
, buf
);
1835 cie_pointer
= read_4_bytes (unit
->abfd
, buf
);
1839 if (cie_pointer
== cie_id
)
1841 /* This is a CIE. */
1842 struct dwarf2_cie
*cie
;
1844 unsigned int cie_version
;
1846 /* Check that a CIE was expected. */
1847 if ((entry_type
& EH_CIE_TYPE_ID
) == 0)
1848 error (_("Found a CIE when not expecting it."));
1850 /* Record the offset into the .debug_frame section of this CIE. */
1851 cie_pointer
= start
- unit
->dwarf_frame_buffer
;
1853 /* Check whether we've already read it. */
1854 if (find_cie (cie_table
, cie_pointer
))
1857 cie
= XOBNEW (&unit
->objfile
->objfile_obstack
, struct dwarf2_cie
);
1858 cie
->initial_instructions
= NULL
;
1859 cie
->cie_pointer
= cie_pointer
;
1861 /* The encoding for FDE's in a normal .debug_frame section
1862 depends on the target address size. */
1863 cie
->encoding
= DW_EH_PE_absptr
;
1865 /* We'll determine the final value later, but we need to
1866 initialize it conservatively. */
1867 cie
->signal_frame
= 0;
1869 /* Check version number. */
1870 cie_version
= read_1_byte (unit
->abfd
, buf
);
1871 if (cie_version
!= 1 && cie_version
!= 3 && cie_version
!= 4)
1873 cie
->version
= cie_version
;
1876 /* Interpret the interesting bits of the augmentation. */
1877 cie
->augmentation
= augmentation
= (char *) buf
;
1878 buf
+= (strlen (augmentation
) + 1);
1880 /* Ignore armcc augmentations. We only use them for quirks,
1881 and that doesn't happen until later. */
1882 if (startswith (augmentation
, "armcc"))
1883 augmentation
+= strlen (augmentation
);
1885 /* The GCC 2.x "eh" augmentation has a pointer immediately
1886 following the augmentation string, so it must be handled
1888 if (augmentation
[0] == 'e' && augmentation
[1] == 'h')
1891 buf
+= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1895 if (cie
->version
>= 4)
1897 /* FIXME: check that this is the same as from the CU header. */
1898 cie
->addr_size
= read_1_byte (unit
->abfd
, buf
);
1900 cie
->segment_size
= read_1_byte (unit
->abfd
, buf
);
1905 cie
->addr_size
= gdbarch_dwarf2_addr_size (gdbarch
);
1906 cie
->segment_size
= 0;
1908 /* Address values in .eh_frame sections are defined to have the
1909 target's pointer size. Watchout: This breaks frame info for
1910 targets with pointer size < address size, unless a .debug_frame
1911 section exists as well. */
1913 cie
->ptr_size
= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1915 cie
->ptr_size
= cie
->addr_size
;
1917 buf
= gdb_read_uleb128 (buf
, end
, &uleb128
);
1920 cie
->code_alignment_factor
= uleb128
;
1922 buf
= gdb_read_sleb128 (buf
, end
, &sleb128
);
1925 cie
->data_alignment_factor
= sleb128
;
1927 if (cie_version
== 1)
1929 cie
->return_address_register
= read_1_byte (unit
->abfd
, buf
);
1934 buf
= gdb_read_uleb128 (buf
, end
, &uleb128
);
1937 cie
->return_address_register
= uleb128
;
1940 cie
->return_address_register
1941 = dwarf2_frame_adjust_regnum (gdbarch
,
1942 cie
->return_address_register
,
1945 cie
->saw_z_augmentation
= (*augmentation
== 'z');
1946 if (cie
->saw_z_augmentation
)
1950 buf
= gdb_read_uleb128 (buf
, end
, &length
);
1953 cie
->initial_instructions
= buf
+ length
;
1957 while (*augmentation
)
1959 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1960 if (*augmentation
== 'L')
1967 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1968 else if (*augmentation
== 'R')
1970 cie
->encoding
= *buf
++;
1974 /* "P" indicates a personality routine in the CIE augmentation. */
1975 else if (*augmentation
== 'P')
1977 /* Skip. Avoid indirection since we throw away the result. */
1978 gdb_byte encoding
= (*buf
++) & ~DW_EH_PE_indirect
;
1979 read_encoded_value (unit
, encoding
, cie
->ptr_size
,
1980 buf
, &bytes_read
, 0);
1985 /* "S" indicates a signal frame, such that the return
1986 address must not be decremented to locate the call frame
1987 info for the previous frame; it might even be the first
1988 instruction of a function, so decrementing it would take
1989 us to a different function. */
1990 else if (*augmentation
== 'S')
1992 cie
->signal_frame
= 1;
1996 /* Otherwise we have an unknown augmentation. Assume that either
1997 there is no augmentation data, or we saw a 'z' prefix. */
2000 if (cie
->initial_instructions
)
2001 buf
= cie
->initial_instructions
;
2006 cie
->initial_instructions
= buf
;
2010 add_cie (cie_table
, cie
);
2014 /* This is a FDE. */
2015 struct dwarf2_fde
*fde
;
2018 /* Check that an FDE was expected. */
2019 if ((entry_type
& EH_FDE_TYPE_ID
) == 0)
2020 error (_("Found an FDE when not expecting it."));
2022 /* In an .eh_frame section, the CIE pointer is the delta between the
2023 address within the FDE where the CIE pointer is stored and the
2024 address of the CIE. Convert it to an offset into the .eh_frame
2028 cie_pointer
= buf
- unit
->dwarf_frame_buffer
- cie_pointer
;
2029 cie_pointer
-= (dwarf64_p
? 8 : 4);
2032 /* In either case, validate the result is still within the section. */
2033 if (cie_pointer
>= unit
->dwarf_frame_size
)
2036 fde
= XOBNEW (&unit
->objfile
->objfile_obstack
, struct dwarf2_fde
);
2037 fde
->cie
= find_cie (cie_table
, cie_pointer
);
2038 if (fde
->cie
== NULL
)
2040 decode_frame_entry (unit
, unit
->dwarf_frame_buffer
+ cie_pointer
,
2041 eh_frame_p
, cie_table
, fde_table
,
2043 fde
->cie
= find_cie (cie_table
, cie_pointer
);
2046 gdb_assert (fde
->cie
!= NULL
);
2048 addr
= read_encoded_value (unit
, fde
->cie
->encoding
, fde
->cie
->ptr_size
,
2049 buf
, &bytes_read
, 0);
2050 fde
->initial_location
= gdbarch_adjust_dwarf2_addr (gdbarch
, addr
);
2053 fde
->address_range
=
2054 read_encoded_value (unit
, fde
->cie
->encoding
& 0x0f,
2055 fde
->cie
->ptr_size
, buf
, &bytes_read
, 0);
2056 addr
= gdbarch_adjust_dwarf2_addr (gdbarch
, addr
+ fde
->address_range
);
2057 fde
->address_range
= addr
- fde
->initial_location
;
2060 /* A 'z' augmentation in the CIE implies the presence of an
2061 augmentation field in the FDE as well. The only thing known
2062 to be in here at present is the LSDA entry for EH. So we
2063 can skip the whole thing. */
2064 if (fde
->cie
->saw_z_augmentation
)
2068 buf
= gdb_read_uleb128 (buf
, end
, &length
);
2076 fde
->instructions
= buf
;
2079 fde
->eh_frame_p
= eh_frame_p
;
2081 add_fde (fde_table
, fde
);
2087 /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
2088 expect an FDE or a CIE. */
2090 static const gdb_byte
*
2091 decode_frame_entry (struct comp_unit
*unit
, const gdb_byte
*start
,
2093 struct dwarf2_cie_table
*cie_table
,
2094 struct dwarf2_fde_table
*fde_table
,
2095 enum eh_frame_type entry_type
)
2097 enum { NONE
, ALIGN4
, ALIGN8
, FAIL
} workaround
= NONE
;
2098 const gdb_byte
*ret
;
2099 ptrdiff_t start_offset
;
2103 ret
= decode_frame_entry_1 (unit
, start
, eh_frame_p
,
2104 cie_table
, fde_table
, entry_type
);
2108 /* We have corrupt input data of some form. */
2110 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
2111 and mismatches wrt padding and alignment of debug sections. */
2112 /* Note that there is no requirement in the standard for any
2113 alignment at all in the frame unwind sections. Testing for
2114 alignment before trying to interpret data would be incorrect.
2116 However, GCC traditionally arranged for frame sections to be
2117 sized such that the FDE length and CIE fields happen to be
2118 aligned (in theory, for performance). This, unfortunately,
2119 was done with .align directives, which had the side effect of
2120 forcing the section to be aligned by the linker.
2122 This becomes a problem when you have some other producer that
2123 creates frame sections that are not as strictly aligned. That
2124 produces a hole in the frame info that gets filled by the
2127 The GCC behaviour is arguably a bug, but it's effectively now
2128 part of the ABI, so we're now stuck with it, at least at the
2129 object file level. A smart linker may decide, in the process
2130 of compressing duplicate CIE information, that it can rewrite
2131 the entire output section without this extra padding. */
2133 start_offset
= start
- unit
->dwarf_frame_buffer
;
2134 if (workaround
< ALIGN4
&& (start_offset
& 3) != 0)
2136 start
+= 4 - (start_offset
& 3);
2137 workaround
= ALIGN4
;
2140 if (workaround
< ALIGN8
&& (start_offset
& 7) != 0)
2142 start
+= 8 - (start_offset
& 7);
2143 workaround
= ALIGN8
;
2147 /* Nothing left to try. Arrange to return as if we've consumed
2148 the entire input section. Hopefully we'll get valid info from
2149 the other of .debug_frame/.eh_frame. */
2151 ret
= unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
;
2161 complaint (&symfile_complaints
, _("\
2162 Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
2163 unit
->dwarf_frame_section
->owner
->filename
,
2164 unit
->dwarf_frame_section
->name
);
2168 complaint (&symfile_complaints
, _("\
2169 Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
2170 unit
->dwarf_frame_section
->owner
->filename
,
2171 unit
->dwarf_frame_section
->name
);
2175 complaint (&symfile_complaints
,
2176 _("Corrupt data in %s:%s"),
2177 unit
->dwarf_frame_section
->owner
->filename
,
2178 unit
->dwarf_frame_section
->name
);
2186 qsort_fde_cmp (const void *a
, const void *b
)
2188 struct dwarf2_fde
*aa
= *(struct dwarf2_fde
**)a
;
2189 struct dwarf2_fde
*bb
= *(struct dwarf2_fde
**)b
;
2191 if (aa
->initial_location
== bb
->initial_location
)
2193 if (aa
->address_range
!= bb
->address_range
2194 && aa
->eh_frame_p
== 0 && bb
->eh_frame_p
== 0)
2195 /* Linker bug, e.g. gold/10400.
2196 Work around it by keeping stable sort order. */
2197 return (a
< b
) ? -1 : 1;
2199 /* Put eh_frame entries after debug_frame ones. */
2200 return aa
->eh_frame_p
- bb
->eh_frame_p
;
2203 return (aa
->initial_location
< bb
->initial_location
) ? -1 : 1;
2207 dwarf2_build_frame_info (struct objfile
*objfile
)
2209 struct comp_unit
*unit
;
2210 const gdb_byte
*frame_ptr
;
2211 struct dwarf2_cie_table cie_table
;
2212 struct dwarf2_fde_table fde_table
;
2213 struct dwarf2_fde_table
*fde_table2
;
2215 cie_table
.num_entries
= 0;
2216 cie_table
.entries
= NULL
;
2218 fde_table
.num_entries
= 0;
2219 fde_table
.entries
= NULL
;
2221 /* Build a minimal decoding of the DWARF2 compilation unit. */
2222 unit
= (struct comp_unit
*) obstack_alloc (&objfile
->objfile_obstack
,
2223 sizeof (struct comp_unit
));
2224 unit
->abfd
= objfile
->obfd
;
2225 unit
->objfile
= objfile
;
2229 if (objfile
->separate_debug_objfile_backlink
== NULL
)
2231 /* Do not read .eh_frame from separate file as they must be also
2232 present in the main file. */
2233 dwarf2_get_section_info (objfile
, DWARF2_EH_FRAME
,
2234 &unit
->dwarf_frame_section
,
2235 &unit
->dwarf_frame_buffer
,
2236 &unit
->dwarf_frame_size
);
2237 if (unit
->dwarf_frame_size
)
2239 asection
*got
, *txt
;
2241 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2242 that is used for the i386/amd64 target, which currently is
2243 the only target in GCC that supports/uses the
2244 DW_EH_PE_datarel encoding. */
2245 got
= bfd_get_section_by_name (unit
->abfd
, ".got");
2247 unit
->dbase
= got
->vma
;
2249 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2251 txt
= bfd_get_section_by_name (unit
->abfd
, ".text");
2253 unit
->tbase
= txt
->vma
;
2257 frame_ptr
= unit
->dwarf_frame_buffer
;
2258 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2259 frame_ptr
= decode_frame_entry (unit
, frame_ptr
, 1,
2260 &cie_table
, &fde_table
,
2261 EH_CIE_OR_FDE_TYPE_ID
);
2264 CATCH (e
, RETURN_MASK_ERROR
)
2266 warning (_("skipping .eh_frame info of %s: %s"),
2267 objfile_name (objfile
), e
.message
);
2269 if (fde_table
.num_entries
!= 0)
2271 xfree (fde_table
.entries
);
2272 fde_table
.entries
= NULL
;
2273 fde_table
.num_entries
= 0;
2275 /* The cie_table is discarded by the next if. */
2279 if (cie_table
.num_entries
!= 0)
2281 /* Reinit cie_table: debug_frame has different CIEs. */
2282 xfree (cie_table
.entries
);
2283 cie_table
.num_entries
= 0;
2284 cie_table
.entries
= NULL
;
2289 dwarf2_get_section_info (objfile
, DWARF2_DEBUG_FRAME
,
2290 &unit
->dwarf_frame_section
,
2291 &unit
->dwarf_frame_buffer
,
2292 &unit
->dwarf_frame_size
);
2293 if (unit
->dwarf_frame_size
)
2295 int num_old_fde_entries
= fde_table
.num_entries
;
2299 frame_ptr
= unit
->dwarf_frame_buffer
;
2300 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2301 frame_ptr
= decode_frame_entry (unit
, frame_ptr
, 0,
2302 &cie_table
, &fde_table
,
2303 EH_CIE_OR_FDE_TYPE_ID
);
2305 CATCH (e
, RETURN_MASK_ERROR
)
2307 warning (_("skipping .debug_frame info of %s: %s"),
2308 objfile_name (objfile
), e
.message
);
2310 if (fde_table
.num_entries
!= 0)
2312 fde_table
.num_entries
= num_old_fde_entries
;
2313 if (num_old_fde_entries
== 0)
2315 xfree (fde_table
.entries
);
2316 fde_table
.entries
= NULL
;
2321 = XRESIZEVEC (struct dwarf2_fde
*, fde_table
.entries
,
2322 fde_table
.num_entries
);
2325 fde_table
.num_entries
= num_old_fde_entries
;
2326 /* The cie_table is discarded by the next if. */
2331 /* Discard the cie_table, it is no longer needed. */
2332 if (cie_table
.num_entries
!= 0)
2334 xfree (cie_table
.entries
);
2335 cie_table
.entries
= NULL
; /* Paranoia. */
2336 cie_table
.num_entries
= 0; /* Paranoia. */
2339 /* Copy fde_table to obstack: it is needed at runtime. */
2340 fde_table2
= XOBNEW (&objfile
->objfile_obstack
, struct dwarf2_fde_table
);
2342 if (fde_table
.num_entries
== 0)
2344 fde_table2
->entries
= NULL
;
2345 fde_table2
->num_entries
= 0;
2349 struct dwarf2_fde
*fde_prev
= NULL
;
2350 struct dwarf2_fde
*first_non_zero_fde
= NULL
;
2353 /* Prepare FDE table for lookups. */
2354 qsort (fde_table
.entries
, fde_table
.num_entries
,
2355 sizeof (fde_table
.entries
[0]), qsort_fde_cmp
);
2357 /* Check for leftovers from --gc-sections. The GNU linker sets
2358 the relevant symbols to zero, but doesn't zero the FDE *end*
2359 ranges because there's no relocation there. It's (offset,
2360 length), not (start, end). On targets where address zero is
2361 just another valid address this can be a problem, since the
2362 FDEs appear to be non-empty in the output --- we could pick
2363 out the wrong FDE. To work around this, when overlaps are
2364 detected, we prefer FDEs that do not start at zero.
2366 Start by finding the first FDE with non-zero start. Below
2367 we'll discard all FDEs that start at zero and overlap this
2369 for (i
= 0; i
< fde_table
.num_entries
; i
++)
2371 struct dwarf2_fde
*fde
= fde_table
.entries
[i
];
2373 if (fde
->initial_location
!= 0)
2375 first_non_zero_fde
= fde
;
2380 /* Since we'll be doing bsearch, squeeze out identical (except
2381 for eh_frame_p) fde entries so bsearch result is predictable.
2382 Also discard leftovers from --gc-sections. */
2383 fde_table2
->num_entries
= 0;
2384 for (i
= 0; i
< fde_table
.num_entries
; i
++)
2386 struct dwarf2_fde
*fde
= fde_table
.entries
[i
];
2388 if (fde
->initial_location
== 0
2389 && first_non_zero_fde
!= NULL
2390 && (first_non_zero_fde
->initial_location
2391 < fde
->initial_location
+ fde
->address_range
))
2394 if (fde_prev
!= NULL
2395 && fde_prev
->initial_location
== fde
->initial_location
)
2398 obstack_grow (&objfile
->objfile_obstack
, &fde_table
.entries
[i
],
2399 sizeof (fde_table
.entries
[0]));
2400 ++fde_table2
->num_entries
;
2404 = (struct dwarf2_fde
**) obstack_finish (&objfile
->objfile_obstack
);
2406 /* Discard the original fde_table. */
2407 xfree (fde_table
.entries
);
2410 set_objfile_data (objfile
, dwarf2_frame_objfile_data
, fde_table2
);
2413 /* Provide a prototype to silence -Wmissing-prototypes. */
2414 void _initialize_dwarf2_frame (void);
2417 _initialize_dwarf2_frame (void)
2419 dwarf2_frame_data
= gdbarch_data_register_pre_init (dwarf2_frame_init
);
2420 dwarf2_frame_objfile_data
= register_objfile_data ();
2423 register_self_test_foreach_arch (selftests::execute_cfa_program_test
);