1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright (C) 2003-2019 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"
38 #include "dwarf2read.h"
40 #include "dwarf2loc.h"
41 #include "dwarf2-frame-tailcall.h"
43 #include "gdbsupport/selftest.h"
44 #include "selftest-arch.h"
46 #include <unordered_map>
52 /* Call Frame Information (CFI). */
54 /* Common Information Entry (CIE). */
58 /* Computation Unit for this CIE. */
59 struct comp_unit
*unit
;
61 /* Offset into the .debug_frame section where this CIE was found.
62 Used to identify this CIE. */
65 /* Constant that is factored out of all advance location
67 ULONGEST code_alignment_factor
;
69 /* Constants that is factored out of all offset instructions. */
70 LONGEST data_alignment_factor
;
72 /* Return address column. */
73 ULONGEST return_address_register
;
75 /* Instruction sequence to initialize a register set. */
76 const gdb_byte
*initial_instructions
;
79 /* Saved augmentation, in case it's needed later. */
82 /* Encoding of addresses. */
85 /* Target address size in bytes. */
88 /* Target pointer size in bytes. */
91 /* True if a 'z' augmentation existed. */
92 unsigned char saw_z_augmentation
;
94 /* True if an 'S' augmentation existed. */
95 unsigned char signal_frame
;
97 /* The version recorded in the CIE. */
98 unsigned char version
;
100 /* The segment size. */
101 unsigned char segment_size
;
104 /* The CIE table is used to find CIEs during parsing, but then
105 discarded. It maps from the CIE's offset to the CIE. */
106 typedef std::unordered_map
<ULONGEST
, dwarf2_cie
*> dwarf2_cie_table
;
108 /* Frame Description Entry (FDE). */
112 /* CIE for this FDE. */
113 struct dwarf2_cie
*cie
;
115 /* First location associated with this FDE. */
116 CORE_ADDR initial_location
;
118 /* Number of bytes of program instructions described by this FDE. */
119 CORE_ADDR address_range
;
121 /* Instruction sequence. */
122 const gdb_byte
*instructions
;
125 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
127 unsigned char eh_frame_p
;
130 struct dwarf2_fde_table
133 struct dwarf2_fde
**entries
;
136 /* A minimal decoding of DWARF2 compilation units. We only decode
137 what's needed to get to the call frame information. */
141 /* Keep the bfd convenient. */
144 struct objfile
*objfile
;
146 /* Pointer to the .debug_frame section loaded into memory. */
147 const gdb_byte
*dwarf_frame_buffer
;
149 /* Length of the loaded .debug_frame section. */
150 bfd_size_type dwarf_frame_size
;
152 /* Pointer to the .debug_frame section. */
153 asection
*dwarf_frame_section
;
155 /* Base for DW_EH_PE_datarel encodings. */
158 /* Base for DW_EH_PE_textrel encodings. */
162 static struct dwarf2_fde
*dwarf2_frame_find_fde (CORE_ADDR
*pc
,
163 CORE_ADDR
*out_offset
);
165 static int dwarf2_frame_adjust_regnum (struct gdbarch
*gdbarch
, int regnum
,
168 static CORE_ADDR
read_encoded_value (struct comp_unit
*unit
, gdb_byte encoding
,
169 int ptr_len
, const gdb_byte
*buf
,
170 unsigned int *bytes_read_ptr
,
171 CORE_ADDR func_base
);
174 /* See dwarf2-frame.h. */
175 bool dwarf2_frame_unwinders_enabled_p
= true;
177 /* Store the length the expression for the CFA in the `cfa_reg' field,
178 which is unused in that case. */
179 #define cfa_exp_len cfa_reg
181 dwarf2_frame_state::dwarf2_frame_state (CORE_ADDR pc_
, struct dwarf2_cie
*cie
)
182 : pc (pc_
), data_align (cie
->data_alignment_factor
),
183 code_align (cie
->code_alignment_factor
),
184 retaddr_column (cie
->return_address_register
)
189 /* Helper functions for execute_stack_op. */
192 read_addr_from_reg (struct frame_info
*this_frame
, int reg
)
194 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
195 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, reg
);
197 return address_from_register (regnum
, this_frame
);
200 /* Execute the required actions for both the DW_CFA_restore and
201 DW_CFA_restore_extended instructions. */
203 dwarf2_restore_rule (struct gdbarch
*gdbarch
, ULONGEST reg_num
,
204 struct dwarf2_frame_state
*fs
, int eh_frame_p
)
208 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg_num
, eh_frame_p
);
209 fs
->regs
.alloc_regs (reg
+ 1);
211 /* Check if this register was explicitly initialized in the
212 CIE initial instructions. If not, default the rule to
214 if (reg
< fs
->initial
.reg
.size ())
215 fs
->regs
.reg
[reg
] = fs
->initial
.reg
[reg
];
217 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNSPECIFIED
;
219 if (fs
->regs
.reg
[reg
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
221 int regnum
= dwarf_reg_to_regnum (gdbarch
, reg
);
224 incomplete CFI data; DW_CFA_restore unspecified\n\
225 register %s (#%d) at %s"),
226 gdbarch_register_name (gdbarch
, regnum
), regnum
,
227 paddress (gdbarch
, fs
->pc
));
231 class dwarf_expr_executor
: public dwarf_expr_context
235 struct frame_info
*this_frame
;
237 CORE_ADDR
read_addr_from_reg (int reg
) override
239 return ::read_addr_from_reg (this_frame
, reg
);
242 struct value
*get_reg_value (struct type
*type
, int reg
) override
244 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
245 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, reg
);
247 return value_from_register (type
, regnum
, this_frame
);
250 void read_mem (gdb_byte
*buf
, CORE_ADDR addr
, size_t len
) override
252 read_memory (addr
, buf
, len
);
255 void get_frame_base (const gdb_byte
**start
, size_t *length
) override
257 invalid ("DW_OP_fbreg");
260 void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind
,
261 union call_site_parameter_u kind_u
,
262 int deref_size
) override
264 invalid ("DW_OP_entry_value");
267 CORE_ADDR
get_object_address () override
269 invalid ("DW_OP_push_object_address");
272 CORE_ADDR
get_frame_cfa () override
274 invalid ("DW_OP_call_frame_cfa");
277 CORE_ADDR
get_tls_address (CORE_ADDR offset
) override
279 invalid ("DW_OP_form_tls_address");
282 void dwarf_call (cu_offset die_offset
) override
284 invalid ("DW_OP_call*");
287 struct value
*dwarf_variable_value (sect_offset sect_off
) override
289 invalid ("DW_OP_GNU_variable_value");
292 CORE_ADDR
get_addr_index (unsigned int index
) override
294 invalid ("DW_OP_addrx or DW_OP_GNU_addr_index");
299 void invalid (const char *op
) ATTRIBUTE_NORETURN
301 error (_("%s is invalid in this context"), op
);
306 execute_stack_op (const gdb_byte
*exp
, ULONGEST len
, int addr_size
,
307 CORE_ADDR offset
, struct frame_info
*this_frame
,
308 CORE_ADDR initial
, int initial_in_stack_memory
)
312 dwarf_expr_executor ctx
;
313 scoped_value_mark free_values
;
315 ctx
.this_frame
= this_frame
;
316 ctx
.gdbarch
= get_frame_arch (this_frame
);
317 ctx
.addr_size
= addr_size
;
318 ctx
.ref_addr_size
= -1;
321 ctx
.push_address (initial
, initial_in_stack_memory
);
324 if (ctx
.location
== DWARF_VALUE_MEMORY
)
325 result
= ctx
.fetch_address (0);
326 else if (ctx
.location
== DWARF_VALUE_REGISTER
)
327 result
= ctx
.read_addr_from_reg (value_as_long (ctx
.fetch (0)));
330 /* This is actually invalid DWARF, but if we ever do run across
331 it somehow, we might as well support it. So, instead, report
332 it as unimplemented. */
334 Not implemented: computing unwound register using explicit value operator"));
341 /* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior
342 PC. Modify FS state accordingly. Return current INSN_PTR where the
343 execution has stopped, one can resume it on the next call. */
345 static const gdb_byte
*
346 execute_cfa_program (struct dwarf2_fde
*fde
, const gdb_byte
*insn_ptr
,
347 const gdb_byte
*insn_end
, struct gdbarch
*gdbarch
,
348 CORE_ADDR pc
, struct dwarf2_frame_state
*fs
)
350 int eh_frame_p
= fde
->eh_frame_p
;
351 unsigned int bytes_read
;
352 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
354 while (insn_ptr
< insn_end
&& fs
->pc
<= pc
)
356 gdb_byte insn
= *insn_ptr
++;
360 if ((insn
& 0xc0) == DW_CFA_advance_loc
)
361 fs
->pc
+= (insn
& 0x3f) * fs
->code_align
;
362 else if ((insn
& 0xc0) == DW_CFA_offset
)
365 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
366 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
367 offset
= utmp
* fs
->data_align
;
368 fs
->regs
.alloc_regs (reg
+ 1);
369 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
370 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
372 else if ((insn
& 0xc0) == DW_CFA_restore
)
375 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
382 fs
->pc
= read_encoded_value (fde
->cie
->unit
, fde
->cie
->encoding
,
383 fde
->cie
->ptr_size
, insn_ptr
,
384 &bytes_read
, fde
->initial_location
);
385 /* Apply the objfile offset for relocatable objects. */
386 fs
->pc
+= ANOFFSET (fde
->cie
->unit
->objfile
->section_offsets
,
387 SECT_OFF_TEXT (fde
->cie
->unit
->objfile
));
388 insn_ptr
+= bytes_read
;
391 case DW_CFA_advance_loc1
:
392 utmp
= extract_unsigned_integer (insn_ptr
, 1, byte_order
);
393 fs
->pc
+= utmp
* fs
->code_align
;
396 case DW_CFA_advance_loc2
:
397 utmp
= extract_unsigned_integer (insn_ptr
, 2, byte_order
);
398 fs
->pc
+= utmp
* fs
->code_align
;
401 case DW_CFA_advance_loc4
:
402 utmp
= extract_unsigned_integer (insn_ptr
, 4, byte_order
);
403 fs
->pc
+= utmp
* fs
->code_align
;
407 case DW_CFA_offset_extended
:
408 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
409 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
410 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
411 offset
= utmp
* fs
->data_align
;
412 fs
->regs
.alloc_regs (reg
+ 1);
413 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
414 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
417 case DW_CFA_restore_extended
:
418 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
419 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
422 case DW_CFA_undefined
:
423 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
424 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
425 fs
->regs
.alloc_regs (reg
+ 1);
426 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNDEFINED
;
429 case DW_CFA_same_value
:
430 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
431 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
432 fs
->regs
.alloc_regs (reg
+ 1);
433 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAME_VALUE
;
436 case DW_CFA_register
:
437 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
438 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
439 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
440 utmp
= dwarf2_frame_adjust_regnum (gdbarch
, utmp
, eh_frame_p
);
441 fs
->regs
.alloc_regs (reg
+ 1);
442 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_REG
;
443 fs
->regs
.reg
[reg
].loc
.reg
= utmp
;
446 case DW_CFA_remember_state
:
448 struct dwarf2_frame_state_reg_info
*new_rs
;
450 new_rs
= new dwarf2_frame_state_reg_info (fs
->regs
);
451 fs
->regs
.prev
= new_rs
;
455 case DW_CFA_restore_state
:
457 struct dwarf2_frame_state_reg_info
*old_rs
= fs
->regs
.prev
;
462 bad CFI data; mismatched DW_CFA_restore_state at %s"),
463 paddress (gdbarch
, fs
->pc
));
466 fs
->regs
= std::move (*old_rs
);
471 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
472 fs
->regs
.cfa_reg
= reg
;
473 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
475 if (fs
->armcc_cfa_offsets_sf
)
476 utmp
*= fs
->data_align
;
478 fs
->regs
.cfa_offset
= utmp
;
479 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
482 case DW_CFA_def_cfa_register
:
483 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
484 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
,
486 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
489 case DW_CFA_def_cfa_offset
:
490 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
492 if (fs
->armcc_cfa_offsets_sf
)
493 utmp
*= fs
->data_align
;
495 fs
->regs
.cfa_offset
= utmp
;
496 /* cfa_how deliberately not set. */
502 case DW_CFA_def_cfa_expression
:
503 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
504 fs
->regs
.cfa_exp_len
= utmp
;
505 fs
->regs
.cfa_exp
= insn_ptr
;
506 fs
->regs
.cfa_how
= CFA_EXP
;
507 insn_ptr
+= fs
->regs
.cfa_exp_len
;
510 case DW_CFA_expression
:
511 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
512 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
513 fs
->regs
.alloc_regs (reg
+ 1);
514 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
515 fs
->regs
.reg
[reg
].loc
.exp
.start
= insn_ptr
;
516 fs
->regs
.reg
[reg
].loc
.exp
.len
= utmp
;
517 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_EXP
;
521 case DW_CFA_offset_extended_sf
:
522 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
523 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
524 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
525 offset
*= fs
->data_align
;
526 fs
->regs
.alloc_regs (reg
+ 1);
527 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
528 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
531 case DW_CFA_val_offset
:
532 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
533 fs
->regs
.alloc_regs (reg
+ 1);
534 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
535 offset
= utmp
* 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_offset_sf
:
541 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
542 fs
->regs
.alloc_regs (reg
+ 1);
543 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
544 offset
*= fs
->data_align
;
545 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_OFFSET
;
546 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
549 case DW_CFA_val_expression
:
550 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
551 fs
->regs
.alloc_regs (reg
+ 1);
552 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
553 fs
->regs
.reg
[reg
].loc
.exp
.start
= insn_ptr
;
554 fs
->regs
.reg
[reg
].loc
.exp
.len
= utmp
;
555 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_EXP
;
559 case DW_CFA_def_cfa_sf
:
560 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
561 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
,
563 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
564 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
565 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
568 case DW_CFA_def_cfa_offset_sf
:
569 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
570 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
571 /* cfa_how deliberately not set. */
574 case DW_CFA_GNU_args_size
:
576 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
579 case DW_CFA_GNU_negative_offset_extended
:
580 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
581 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
582 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
583 offset
= utmp
* fs
->data_align
;
584 fs
->regs
.alloc_regs (reg
+ 1);
585 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
586 fs
->regs
.reg
[reg
].loc
.offset
= -offset
;
590 if (insn
>= DW_CFA_lo_user
&& insn
<= DW_CFA_hi_user
)
592 /* Handle vendor-specific CFI for different architectures. */
593 if (!gdbarch_execute_dwarf_cfa_vendor_op (gdbarch
, insn
, fs
))
594 error (_("Call Frame Instruction op %d in vendor extension "
595 "space is not handled on this architecture."),
599 internal_error (__FILE__
, __LINE__
,
600 _("Unknown CFI encountered."));
605 if (fs
->initial
.reg
.empty ())
607 /* Don't allow remember/restore between CIE and FDE programs. */
608 delete fs
->regs
.prev
;
609 fs
->regs
.prev
= NULL
;
617 namespace selftests
{
619 /* Unit test to function execute_cfa_program. */
622 execute_cfa_program_test (struct gdbarch
*gdbarch
)
624 struct dwarf2_fde fde
;
625 struct dwarf2_cie cie
;
627 memset (&fde
, 0, sizeof fde
);
628 memset (&cie
, 0, sizeof cie
);
630 cie
.data_alignment_factor
= -4;
631 cie
.code_alignment_factor
= 2;
634 dwarf2_frame_state
fs (0, fde
.cie
);
638 DW_CFA_def_cfa
, 1, 4, /* DW_CFA_def_cfa: r1 ofs 4 */
639 DW_CFA_offset
| 0x2, 1, /* DW_CFA_offset: r2 at cfa-4 */
640 DW_CFA_remember_state
,
641 DW_CFA_restore_state
,
644 const gdb_byte
*insn_end
= insns
+ sizeof (insns
);
645 const gdb_byte
*out
= execute_cfa_program (&fde
, insns
, insn_end
, gdbarch
,
648 SELF_CHECK (out
== insn_end
);
649 SELF_CHECK (fs
.pc
== 0);
651 /* The instructions above only use r1 and r2, but the register numbers
652 used are adjusted by dwarf2_frame_adjust_regnum. */
653 auto r1
= dwarf2_frame_adjust_regnum (gdbarch
, 1, fde
.eh_frame_p
);
654 auto r2
= dwarf2_frame_adjust_regnum (gdbarch
, 2, fde
.eh_frame_p
);
656 SELF_CHECK (fs
.regs
.reg
.size () == (std::max (r1
, r2
) + 1));
658 SELF_CHECK (fs
.regs
.reg
[r2
].how
== DWARF2_FRAME_REG_SAVED_OFFSET
);
659 SELF_CHECK (fs
.regs
.reg
[r2
].loc
.offset
== -4);
661 for (auto i
= 0; i
< fs
.regs
.reg
.size (); i
++)
663 SELF_CHECK (fs
.regs
.reg
[i
].how
== DWARF2_FRAME_REG_UNSPECIFIED
);
665 SELF_CHECK (fs
.regs
.cfa_reg
== 1);
666 SELF_CHECK (fs
.regs
.cfa_offset
== 4);
667 SELF_CHECK (fs
.regs
.cfa_how
== CFA_REG_OFFSET
);
668 SELF_CHECK (fs
.regs
.cfa_exp
== NULL
);
669 SELF_CHECK (fs
.regs
.prev
== NULL
);
672 } // namespace selftests
673 #endif /* GDB_SELF_TEST */
677 /* Architecture-specific operations. */
679 /* Per-architecture data key. */
680 static struct gdbarch_data
*dwarf2_frame_data
;
682 struct dwarf2_frame_ops
684 /* Pre-initialize the register state REG for register REGNUM. */
685 void (*init_reg
) (struct gdbarch
*, int, struct dwarf2_frame_state_reg
*,
686 struct frame_info
*);
688 /* Check whether the THIS_FRAME is a signal trampoline. */
689 int (*signal_frame_p
) (struct gdbarch
*, struct frame_info
*);
691 /* Convert .eh_frame register number to DWARF register number, or
692 adjust .debug_frame register number. */
693 int (*adjust_regnum
) (struct gdbarch
*, int, int);
696 /* Default architecture-specific register state initialization
700 dwarf2_frame_default_init_reg (struct gdbarch
*gdbarch
, int regnum
,
701 struct dwarf2_frame_state_reg
*reg
,
702 struct frame_info
*this_frame
)
704 /* If we have a register that acts as a program counter, mark it as
705 a destination for the return address. If we have a register that
706 serves as the stack pointer, arrange for it to be filled with the
707 call frame address (CFA). The other registers are marked as
710 We copy the return address to the program counter, since many
711 parts in GDB assume that it is possible to get the return address
712 by unwinding the program counter register. However, on ISA's
713 with a dedicated return address register, the CFI usually only
714 contains information to unwind that return address register.
716 The reason we're treating the stack pointer special here is
717 because in many cases GCC doesn't emit CFI for the stack pointer
718 and implicitly assumes that it is equal to the CFA. This makes
719 some sense since the DWARF specification (version 3, draft 8,
722 "Typically, the CFA is defined to be the value of the stack
723 pointer at the call site in the previous frame (which may be
724 different from its value on entry to the current frame)."
726 However, this isn't true for all platforms supported by GCC
727 (e.g. IBM S/390 and zSeries). Those architectures should provide
728 their own architecture-specific initialization function. */
730 if (regnum
== gdbarch_pc_regnum (gdbarch
))
731 reg
->how
= DWARF2_FRAME_REG_RA
;
732 else if (regnum
== gdbarch_sp_regnum (gdbarch
))
733 reg
->how
= DWARF2_FRAME_REG_CFA
;
736 /* Return a default for the architecture-specific operations. */
739 dwarf2_frame_init (struct obstack
*obstack
)
741 struct dwarf2_frame_ops
*ops
;
743 ops
= OBSTACK_ZALLOC (obstack
, struct dwarf2_frame_ops
);
744 ops
->init_reg
= dwarf2_frame_default_init_reg
;
748 /* Set the architecture-specific register state initialization
749 function for GDBARCH to INIT_REG. */
752 dwarf2_frame_set_init_reg (struct gdbarch
*gdbarch
,
753 void (*init_reg
) (struct gdbarch
*, int,
754 struct dwarf2_frame_state_reg
*,
755 struct frame_info
*))
757 struct dwarf2_frame_ops
*ops
758 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
760 ops
->init_reg
= init_reg
;
763 /* Pre-initialize the register state REG for register REGNUM. */
766 dwarf2_frame_init_reg (struct gdbarch
*gdbarch
, int regnum
,
767 struct dwarf2_frame_state_reg
*reg
,
768 struct frame_info
*this_frame
)
770 struct dwarf2_frame_ops
*ops
771 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
773 ops
->init_reg (gdbarch
, regnum
, reg
, this_frame
);
776 /* Set the architecture-specific signal trampoline recognition
777 function for GDBARCH to SIGNAL_FRAME_P. */
780 dwarf2_frame_set_signal_frame_p (struct gdbarch
*gdbarch
,
781 int (*signal_frame_p
) (struct gdbarch
*,
782 struct frame_info
*))
784 struct dwarf2_frame_ops
*ops
785 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
787 ops
->signal_frame_p
= signal_frame_p
;
790 /* Query the architecture-specific signal frame recognizer for
794 dwarf2_frame_signal_frame_p (struct gdbarch
*gdbarch
,
795 struct frame_info
*this_frame
)
797 struct dwarf2_frame_ops
*ops
798 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
800 if (ops
->signal_frame_p
== NULL
)
802 return ops
->signal_frame_p (gdbarch
, this_frame
);
805 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
809 dwarf2_frame_set_adjust_regnum (struct gdbarch
*gdbarch
,
810 int (*adjust_regnum
) (struct gdbarch
*,
813 struct dwarf2_frame_ops
*ops
814 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
816 ops
->adjust_regnum
= adjust_regnum
;
819 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
823 dwarf2_frame_adjust_regnum (struct gdbarch
*gdbarch
,
824 int regnum
, int eh_frame_p
)
826 struct dwarf2_frame_ops
*ops
827 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
829 if (ops
->adjust_regnum
== NULL
)
831 return ops
->adjust_regnum (gdbarch
, regnum
, eh_frame_p
);
835 dwarf2_frame_find_quirks (struct dwarf2_frame_state
*fs
,
836 struct dwarf2_fde
*fde
)
838 struct compunit_symtab
*cust
;
840 cust
= find_pc_compunit_symtab (fs
->pc
);
844 if (producer_is_realview (COMPUNIT_PRODUCER (cust
)))
846 if (fde
->cie
->version
== 1)
847 fs
->armcc_cfa_offsets_sf
= 1;
849 if (fde
->cie
->version
== 1)
850 fs
->armcc_cfa_offsets_reversed
= 1;
852 /* The reversed offset problem is present in some compilers
853 using DWARF3, but it was eventually fixed. Check the ARM
854 defined augmentations, which are in the format "armcc" followed
855 by a list of one-character options. The "+" option means
856 this problem is fixed (no quirk needed). If the armcc
857 augmentation is missing, the quirk is needed. */
858 if (fde
->cie
->version
== 3
859 && (!startswith (fde
->cie
->augmentation
, "armcc")
860 || strchr (fde
->cie
->augmentation
+ 5, '+') == NULL
))
861 fs
->armcc_cfa_offsets_reversed
= 1;
868 /* See dwarf2-frame.h. */
871 dwarf2_fetch_cfa_info (struct gdbarch
*gdbarch
, CORE_ADDR pc
,
872 struct dwarf2_per_cu_data
*data
,
873 int *regnum_out
, LONGEST
*offset_out
,
874 CORE_ADDR
*text_offset_out
,
875 const gdb_byte
**cfa_start_out
,
876 const gdb_byte
**cfa_end_out
)
878 struct dwarf2_fde
*fde
;
879 CORE_ADDR text_offset
;
882 /* Find the correct FDE. */
883 fde
= dwarf2_frame_find_fde (&pc1
, &text_offset
);
885 error (_("Could not compute CFA; needed to translate this expression"));
887 dwarf2_frame_state
fs (pc1
, fde
->cie
);
889 /* Check for "quirks" - known bugs in producers. */
890 dwarf2_frame_find_quirks (&fs
, fde
);
892 /* First decode all the insns in the CIE. */
893 execute_cfa_program (fde
, fde
->cie
->initial_instructions
,
894 fde
->cie
->end
, gdbarch
, pc
, &fs
);
896 /* Save the initialized register set. */
897 fs
.initial
= fs
.regs
;
899 /* Then decode the insns in the FDE up to our target PC. */
900 execute_cfa_program (fde
, fde
->instructions
, fde
->end
, gdbarch
, pc
, &fs
);
902 /* Calculate the CFA. */
903 switch (fs
.regs
.cfa_how
)
907 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, fs
.regs
.cfa_reg
);
909 *regnum_out
= regnum
;
910 if (fs
.armcc_cfa_offsets_reversed
)
911 *offset_out
= -fs
.regs
.cfa_offset
;
913 *offset_out
= fs
.regs
.cfa_offset
;
918 *text_offset_out
= text_offset
;
919 *cfa_start_out
= fs
.regs
.cfa_exp
;
920 *cfa_end_out
= fs
.regs
.cfa_exp
+ fs
.regs
.cfa_exp_len
;
924 internal_error (__FILE__
, __LINE__
, _("Unknown CFA rule."));
929 struct dwarf2_frame_cache
931 /* DWARF Call Frame Address. */
934 /* Set if the return address column was marked as unavailable
935 (required non-collected memory or registers to compute). */
936 int unavailable_retaddr
;
938 /* Set if the return address column was marked as undefined. */
939 int undefined_retaddr
;
941 /* Saved registers, indexed by GDB register number, not by DWARF
943 struct dwarf2_frame_state_reg
*reg
;
945 /* Return address register. */
946 struct dwarf2_frame_state_reg retaddr_reg
;
948 /* Target address size in bytes. */
951 /* The .text offset. */
952 CORE_ADDR text_offset
;
954 /* True if we already checked whether this frame is the bottom frame
955 of a virtual tail call frame chain. */
956 int checked_tailcall_bottom
;
958 /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME
959 sequence. If NULL then it is a normal case with no TAILCALL_FRAME
960 involved. Non-bottom frames of a virtual tail call frames chain use
961 dwarf2_tailcall_frame_unwind unwinder so this field does not apply for
963 void *tailcall_cache
;
965 /* The number of bytes to subtract from TAILCALL_FRAME frames frame
966 base to get the SP, to simulate the return address pushed on the
968 LONGEST entry_cfa_sp_offset
;
969 int entry_cfa_sp_offset_p
;
972 static struct dwarf2_frame_cache
*
973 dwarf2_frame_cache (struct frame_info
*this_frame
, void **this_cache
)
975 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
976 const int num_regs
= gdbarch_num_cooked_regs (gdbarch
);
977 struct dwarf2_frame_cache
*cache
;
978 struct dwarf2_fde
*fde
;
980 const gdb_byte
*instr
;
983 return (struct dwarf2_frame_cache
*) *this_cache
;
985 /* Allocate a new cache. */
986 cache
= FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache
);
987 cache
->reg
= FRAME_OBSTACK_CALLOC (num_regs
, struct dwarf2_frame_state_reg
);
992 Note that if the next frame is never supposed to return (i.e. a call
993 to abort), the compiler might optimize away the instruction at
994 its return address. As a result the return address will
995 point at some random instruction, and the CFI for that
996 instruction is probably worthless to us. GCC's unwinder solves
997 this problem by substracting 1 from the return address to get an
998 address in the middle of a presumed call instruction (or the
999 instruction in the associated delay slot). This should only be
1000 done for "normal" frames and not for resume-type frames (signal
1001 handlers, sentinel frames, dummy frames). The function
1002 get_frame_address_in_block does just this. It's not clear how
1003 reliable the method is though; there is the potential for the
1004 register state pre-call being different to that on return. */
1005 CORE_ADDR pc1
= get_frame_address_in_block (this_frame
);
1007 /* Find the correct FDE. */
1008 fde
= dwarf2_frame_find_fde (&pc1
, &cache
->text_offset
);
1009 gdb_assert (fde
!= NULL
);
1011 /* Allocate and initialize the frame state. */
1012 struct dwarf2_frame_state
fs (pc1
, fde
->cie
);
1014 cache
->addr_size
= fde
->cie
->addr_size
;
1016 /* Check for "quirks" - known bugs in producers. */
1017 dwarf2_frame_find_quirks (&fs
, fde
);
1019 /* First decode all the insns in the CIE. */
1020 execute_cfa_program (fde
, fde
->cie
->initial_instructions
,
1021 fde
->cie
->end
, gdbarch
,
1022 get_frame_address_in_block (this_frame
), &fs
);
1024 /* Save the initialized register set. */
1025 fs
.initial
= fs
.regs
;
1027 /* Fetching the entry pc for THIS_FRAME won't necessarily result
1028 in an address that's within the range of FDE locations. This
1029 is due to the possibility of the function occupying non-contiguous
1031 if (get_frame_func_if_available (this_frame
, &entry_pc
)
1032 && fde
->initial_location
<= entry_pc
1033 && entry_pc
< fde
->initial_location
+ fde
->address_range
)
1035 /* Decode the insns in the FDE up to the entry PC. */
1036 instr
= execute_cfa_program (fde
, fde
->instructions
, fde
->end
, gdbarch
,
1039 if (fs
.regs
.cfa_how
== CFA_REG_OFFSET
1040 && (dwarf_reg_to_regnum (gdbarch
, fs
.regs
.cfa_reg
)
1041 == gdbarch_sp_regnum (gdbarch
)))
1043 cache
->entry_cfa_sp_offset
= fs
.regs
.cfa_offset
;
1044 cache
->entry_cfa_sp_offset_p
= 1;
1048 instr
= fde
->instructions
;
1050 /* Then decode the insns in the FDE up to our target PC. */
1051 execute_cfa_program (fde
, instr
, fde
->end
, gdbarch
,
1052 get_frame_address_in_block (this_frame
), &fs
);
1056 /* Calculate the CFA. */
1057 switch (fs
.regs
.cfa_how
)
1059 case CFA_REG_OFFSET
:
1060 cache
->cfa
= read_addr_from_reg (this_frame
, fs
.regs
.cfa_reg
);
1061 if (fs
.armcc_cfa_offsets_reversed
)
1062 cache
->cfa
-= fs
.regs
.cfa_offset
;
1064 cache
->cfa
+= fs
.regs
.cfa_offset
;
1069 execute_stack_op (fs
.regs
.cfa_exp
, fs
.regs
.cfa_exp_len
,
1070 cache
->addr_size
, cache
->text_offset
,
1075 internal_error (__FILE__
, __LINE__
, _("Unknown CFA rule."));
1078 catch (const gdb_exception_error
&ex
)
1080 if (ex
.error
== NOT_AVAILABLE_ERROR
)
1082 cache
->unavailable_retaddr
= 1;
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
.reg
.size (); 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
)
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 const std::vector
<struct dwarf2_frame_state_reg
> ®s
1149 ULONGEST retaddr_column
= fs
.retaddr_column
;
1151 /* It seems rather bizarre to specify an "empty" column as
1152 the return adress column. However, this is exactly
1153 what GCC does on some targets. It turns out that GCC
1154 assumes that the return address can be found in the
1155 register corresponding to the return address column.
1156 Incidentally, that's how we should treat a return
1157 address column specifying "same value" too. */
1158 if (fs
.retaddr_column
< fs
.regs
.reg
.size ()
1159 && regs
[retaddr_column
].how
!= DWARF2_FRAME_REG_UNSPECIFIED
1160 && regs
[retaddr_column
].how
!= DWARF2_FRAME_REG_SAME_VALUE
)
1162 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1163 cache
->reg
[regnum
] = regs
[retaddr_column
];
1165 cache
->retaddr_reg
= regs
[retaddr_column
];
1169 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1171 cache
->reg
[regnum
].loc
.reg
= fs
.retaddr_column
;
1172 cache
->reg
[regnum
].how
= DWARF2_FRAME_REG_SAVED_REG
;
1176 cache
->retaddr_reg
.loc
.reg
= fs
.retaddr_column
;
1177 cache
->retaddr_reg
.how
= DWARF2_FRAME_REG_SAVED_REG
;
1184 if (fs
.retaddr_column
< fs
.regs
.reg
.size ()
1185 && fs
.regs
.reg
[fs
.retaddr_column
].how
== DWARF2_FRAME_REG_UNDEFINED
)
1186 cache
->undefined_retaddr
= 1;
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 if (!dwarf2_frame_unwinders_enabled_p
)
1346 /* Grab an address that is guarenteed to reside somewhere within the
1347 function. get_frame_pc(), with a no-return next function, can
1348 end up returning something past the end of this function's body.
1349 If the frame we're sniffing for is a signal frame whose start
1350 address is placed on the stack by the OS, its FDE must
1351 extend one byte before its start address or we could potentially
1352 select the FDE of the previous function. */
1353 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1354 struct dwarf2_fde
*fde
= dwarf2_frame_find_fde (&block_addr
, NULL
);
1359 /* On some targets, signal trampolines may have unwind information.
1360 We need to recognize them so that we set the frame type
1363 if (fde
->cie
->signal_frame
1364 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame
),
1366 return self
->type
== SIGTRAMP_FRAME
;
1368 if (self
->type
!= NORMAL_FRAME
)
1374 static const struct frame_unwind dwarf2_frame_unwind
=
1377 dwarf2_frame_unwind_stop_reason
,
1378 dwarf2_frame_this_id
,
1379 dwarf2_frame_prev_register
,
1381 dwarf2_frame_sniffer
,
1382 dwarf2_frame_dealloc_cache
1385 static const struct frame_unwind dwarf2_signal_frame_unwind
=
1388 dwarf2_frame_unwind_stop_reason
,
1389 dwarf2_frame_this_id
,
1390 dwarf2_frame_prev_register
,
1392 dwarf2_frame_sniffer
,
1394 /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */
1398 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1401 dwarf2_append_unwinders (struct gdbarch
*gdbarch
)
1403 /* TAILCALL_FRAME must be first to find the record by
1404 dwarf2_tailcall_sniffer_first. */
1405 frame_unwind_append_unwinder (gdbarch
, &dwarf2_tailcall_frame_unwind
);
1407 frame_unwind_append_unwinder (gdbarch
, &dwarf2_frame_unwind
);
1408 frame_unwind_append_unwinder (gdbarch
, &dwarf2_signal_frame_unwind
);
1412 /* There is no explicitly defined relationship between the CFA and the
1413 location of frame's local variables and arguments/parameters.
1414 Therefore, frame base methods on this page should probably only be
1415 used as a last resort, just to avoid printing total garbage as a
1416 response to the "info frame" command. */
1419 dwarf2_frame_base_address (struct frame_info
*this_frame
, void **this_cache
)
1421 struct dwarf2_frame_cache
*cache
=
1422 dwarf2_frame_cache (this_frame
, this_cache
);
1427 static const struct frame_base dwarf2_frame_base
=
1429 &dwarf2_frame_unwind
,
1430 dwarf2_frame_base_address
,
1431 dwarf2_frame_base_address
,
1432 dwarf2_frame_base_address
1435 const struct frame_base
*
1436 dwarf2_frame_base_sniffer (struct frame_info
*this_frame
)
1438 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1440 if (dwarf2_frame_find_fde (&block_addr
, NULL
))
1441 return &dwarf2_frame_base
;
1446 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1447 the DWARF unwinder. This is used to implement
1448 DW_OP_call_frame_cfa. */
1451 dwarf2_frame_cfa (struct frame_info
*this_frame
)
1453 if (frame_unwinder_is (this_frame
, &record_btrace_tailcall_frame_unwind
)
1454 || frame_unwinder_is (this_frame
, &record_btrace_frame_unwind
))
1455 throw_error (NOT_AVAILABLE_ERROR
,
1456 _("cfa not available for record btrace target"));
1458 while (get_frame_type (this_frame
) == INLINE_FRAME
)
1459 this_frame
= get_prev_frame (this_frame
);
1460 if (get_frame_unwind_stop_reason (this_frame
) == UNWIND_UNAVAILABLE
)
1461 throw_error (NOT_AVAILABLE_ERROR
,
1462 _("can't compute CFA for this frame: "
1463 "required registers or memory are unavailable"));
1465 if (get_frame_id (this_frame
).stack_status
!= FID_STACK_VALID
)
1466 throw_error (NOT_AVAILABLE_ERROR
,
1467 _("can't compute CFA for this frame: "
1468 "frame base not available"));
1470 return get_frame_base (this_frame
);
1473 const struct objfile_key
<dwarf2_fde_table
,
1474 gdb::noop_deleter
<dwarf2_fde_table
>>
1475 dwarf2_frame_objfile_data
;
1478 read_1_byte (bfd
*abfd
, const gdb_byte
*buf
)
1480 return bfd_get_8 (abfd
, buf
);
1484 read_4_bytes (bfd
*abfd
, const gdb_byte
*buf
)
1486 return bfd_get_32 (abfd
, buf
);
1490 read_8_bytes (bfd
*abfd
, const gdb_byte
*buf
)
1492 return bfd_get_64 (abfd
, buf
);
1496 read_initial_length (bfd
*abfd
, const gdb_byte
*buf
,
1497 unsigned int *bytes_read_ptr
)
1501 result
= bfd_get_32 (abfd
, buf
);
1502 if (result
== 0xffffffff)
1504 result
= bfd_get_64 (abfd
, buf
+ 4);
1505 *bytes_read_ptr
= 12;
1508 *bytes_read_ptr
= 4;
1514 /* Pointer encoding helper functions. */
1516 /* GCC supports exception handling based on DWARF2 CFI. However, for
1517 technical reasons, it encodes addresses in its FDE's in a different
1518 way. Several "pointer encodings" are supported. The encoding
1519 that's used for a particular FDE is determined by the 'R'
1520 augmentation in the associated CIE. The argument of this
1521 augmentation is a single byte.
1523 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1524 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1525 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1526 address should be interpreted (absolute, relative to the current
1527 position in the FDE, ...). Bit 7, indicates that the address
1528 should be dereferenced. */
1531 encoding_for_size (unsigned int size
)
1536 return DW_EH_PE_udata2
;
1538 return DW_EH_PE_udata4
;
1540 return DW_EH_PE_udata8
;
1542 internal_error (__FILE__
, __LINE__
, _("Unsupported address size"));
1547 read_encoded_value (struct comp_unit
*unit
, gdb_byte encoding
,
1548 int ptr_len
, const gdb_byte
*buf
,
1549 unsigned int *bytes_read_ptr
,
1550 CORE_ADDR func_base
)
1555 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1557 if (encoding
& DW_EH_PE_indirect
)
1558 internal_error (__FILE__
, __LINE__
,
1559 _("Unsupported encoding: DW_EH_PE_indirect"));
1561 *bytes_read_ptr
= 0;
1563 switch (encoding
& 0x70)
1565 case DW_EH_PE_absptr
:
1568 case DW_EH_PE_pcrel
:
1569 base
= bfd_section_vma (unit
->dwarf_frame_section
);
1570 base
+= (buf
- unit
->dwarf_frame_buffer
);
1572 case DW_EH_PE_datarel
:
1575 case DW_EH_PE_textrel
:
1578 case DW_EH_PE_funcrel
:
1581 case DW_EH_PE_aligned
:
1583 offset
= buf
- unit
->dwarf_frame_buffer
;
1584 if ((offset
% ptr_len
) != 0)
1586 *bytes_read_ptr
= ptr_len
- (offset
% ptr_len
);
1587 buf
+= *bytes_read_ptr
;
1591 internal_error (__FILE__
, __LINE__
,
1592 _("Invalid or unsupported encoding"));
1595 if ((encoding
& 0x07) == 0x00)
1597 encoding
|= encoding_for_size (ptr_len
);
1598 if (bfd_get_sign_extend_vma (unit
->abfd
))
1599 encoding
|= DW_EH_PE_signed
;
1602 switch (encoding
& 0x0f)
1604 case DW_EH_PE_uleb128
:
1607 const gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1609 *bytes_read_ptr
+= safe_read_uleb128 (buf
, end_buf
, &value
) - buf
;
1610 return base
+ value
;
1612 case DW_EH_PE_udata2
:
1613 *bytes_read_ptr
+= 2;
1614 return (base
+ bfd_get_16 (unit
->abfd
, (bfd_byte
*) buf
));
1615 case DW_EH_PE_udata4
:
1616 *bytes_read_ptr
+= 4;
1617 return (base
+ bfd_get_32 (unit
->abfd
, (bfd_byte
*) buf
));
1618 case DW_EH_PE_udata8
:
1619 *bytes_read_ptr
+= 8;
1620 return (base
+ bfd_get_64 (unit
->abfd
, (bfd_byte
*) buf
));
1621 case DW_EH_PE_sleb128
:
1624 const gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1626 *bytes_read_ptr
+= safe_read_sleb128 (buf
, end_buf
, &value
) - buf
;
1627 return base
+ value
;
1629 case DW_EH_PE_sdata2
:
1630 *bytes_read_ptr
+= 2;
1631 return (base
+ bfd_get_signed_16 (unit
->abfd
, (bfd_byte
*) buf
));
1632 case DW_EH_PE_sdata4
:
1633 *bytes_read_ptr
+= 4;
1634 return (base
+ bfd_get_signed_32 (unit
->abfd
, (bfd_byte
*) buf
));
1635 case DW_EH_PE_sdata8
:
1636 *bytes_read_ptr
+= 8;
1637 return (base
+ bfd_get_signed_64 (unit
->abfd
, (bfd_byte
*) buf
));
1639 internal_error (__FILE__
, __LINE__
,
1640 _("Invalid or unsupported encoding"));
1645 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1646 static struct dwarf2_cie
*
1647 find_cie (const dwarf2_cie_table
&cie_table
, ULONGEST cie_pointer
)
1649 auto iter
= cie_table
.find (cie_pointer
);
1650 if (iter
!= cie_table
.end ())
1651 return iter
->second
;
1656 bsearch_fde_cmp (const void *key
, const void *element
)
1658 CORE_ADDR seek_pc
= *(CORE_ADDR
*) key
;
1659 struct dwarf2_fde
*fde
= *(struct dwarf2_fde
**) element
;
1661 if (seek_pc
< fde
->initial_location
)
1663 if (seek_pc
< fde
->initial_location
+ fde
->address_range
)
1668 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1669 initial location associated with it into *PC. */
1671 static struct dwarf2_fde
*
1672 dwarf2_frame_find_fde (CORE_ADDR
*pc
, CORE_ADDR
*out_offset
)
1674 for (objfile
*objfile
: current_program_space
->objfiles ())
1676 struct dwarf2_fde_table
*fde_table
;
1677 struct dwarf2_fde
**p_fde
;
1681 fde_table
= dwarf2_frame_objfile_data
.get (objfile
);
1682 if (fde_table
== NULL
)
1684 dwarf2_build_frame_info (objfile
);
1685 fde_table
= dwarf2_frame_objfile_data
.get (objfile
);
1687 gdb_assert (fde_table
!= NULL
);
1689 if (fde_table
->num_entries
== 0)
1692 gdb_assert (objfile
->section_offsets
);
1693 offset
= ANOFFSET (objfile
->section_offsets
, SECT_OFF_TEXT (objfile
));
1695 gdb_assert (fde_table
->num_entries
> 0);
1696 if (*pc
< offset
+ fde_table
->entries
[0]->initial_location
)
1699 seek_pc
= *pc
- offset
;
1700 p_fde
= ((struct dwarf2_fde
**)
1701 bsearch (&seek_pc
, fde_table
->entries
, fde_table
->num_entries
,
1702 sizeof (fde_table
->entries
[0]), bsearch_fde_cmp
));
1705 *pc
= (*p_fde
)->initial_location
+ offset
;
1707 *out_offset
= offset
;
1714 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1716 add_fde (struct dwarf2_fde_table
*fde_table
, struct dwarf2_fde
*fde
)
1718 if (fde
->address_range
== 0)
1719 /* Discard useless FDEs. */
1722 fde_table
->num_entries
+= 1;
1723 fde_table
->entries
= XRESIZEVEC (struct dwarf2_fde
*, fde_table
->entries
,
1724 fde_table
->num_entries
);
1725 fde_table
->entries
[fde_table
->num_entries
- 1] = fde
;
1728 #define DW64_CIE_ID 0xffffffffffffffffULL
1730 /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
1735 EH_CIE_TYPE_ID
= 1 << 0,
1736 EH_FDE_TYPE_ID
= 1 << 1,
1737 EH_CIE_OR_FDE_TYPE_ID
= EH_CIE_TYPE_ID
| EH_FDE_TYPE_ID
1740 static const gdb_byte
*decode_frame_entry (struct comp_unit
*unit
,
1741 const gdb_byte
*start
,
1743 dwarf2_cie_table
&cie_table
,
1744 struct dwarf2_fde_table
*fde_table
,
1745 enum eh_frame_type entry_type
);
1747 /* Decode the next CIE or FDE, entry_type specifies the expected type.
1748 Return NULL if invalid input, otherwise the next byte to be processed. */
1750 static const gdb_byte
*
1751 decode_frame_entry_1 (struct comp_unit
*unit
, const gdb_byte
*start
,
1753 dwarf2_cie_table
&cie_table
,
1754 struct dwarf2_fde_table
*fde_table
,
1755 enum eh_frame_type entry_type
)
1757 struct gdbarch
*gdbarch
= get_objfile_arch (unit
->objfile
);
1758 const gdb_byte
*buf
, *end
;
1760 unsigned int bytes_read
;
1763 ULONGEST cie_pointer
;
1768 length
= read_initial_length (unit
->abfd
, buf
, &bytes_read
);
1770 end
= buf
+ (size_t) length
;
1775 /* Are we still within the section? */
1776 if (end
<= buf
|| end
> unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
1779 /* Distinguish between 32 and 64-bit encoded frame info. */
1780 dwarf64_p
= (bytes_read
== 12);
1782 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1786 cie_id
= DW64_CIE_ID
;
1792 cie_pointer
= read_8_bytes (unit
->abfd
, buf
);
1797 cie_pointer
= read_4_bytes (unit
->abfd
, buf
);
1801 if (cie_pointer
== cie_id
)
1803 /* This is a CIE. */
1804 struct dwarf2_cie
*cie
;
1806 unsigned int cie_version
;
1808 /* Check that a CIE was expected. */
1809 if ((entry_type
& EH_CIE_TYPE_ID
) == 0)
1810 error (_("Found a CIE when not expecting it."));
1812 /* Record the offset into the .debug_frame section of this CIE. */
1813 cie_pointer
= start
- unit
->dwarf_frame_buffer
;
1815 /* Check whether we've already read it. */
1816 if (find_cie (cie_table
, cie_pointer
))
1819 cie
= XOBNEW (&unit
->objfile
->objfile_obstack
, struct dwarf2_cie
);
1820 cie
->initial_instructions
= NULL
;
1821 cie
->cie_pointer
= cie_pointer
;
1823 /* The encoding for FDE's in a normal .debug_frame section
1824 depends on the target address size. */
1825 cie
->encoding
= DW_EH_PE_absptr
;
1827 /* We'll determine the final value later, but we need to
1828 initialize it conservatively. */
1829 cie
->signal_frame
= 0;
1831 /* Check version number. */
1832 cie_version
= read_1_byte (unit
->abfd
, buf
);
1833 if (cie_version
!= 1 && cie_version
!= 3 && cie_version
!= 4)
1835 cie
->version
= cie_version
;
1838 /* Interpret the interesting bits of the augmentation. */
1839 cie
->augmentation
= augmentation
= (char *) buf
;
1840 buf
+= (strlen (augmentation
) + 1);
1842 /* Ignore armcc augmentations. We only use them for quirks,
1843 and that doesn't happen until later. */
1844 if (startswith (augmentation
, "armcc"))
1845 augmentation
+= strlen (augmentation
);
1847 /* The GCC 2.x "eh" augmentation has a pointer immediately
1848 following the augmentation string, so it must be handled
1850 if (augmentation
[0] == 'e' && augmentation
[1] == 'h')
1853 buf
+= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1857 if (cie
->version
>= 4)
1859 /* FIXME: check that this is the same as from the CU header. */
1860 cie
->addr_size
= read_1_byte (unit
->abfd
, buf
);
1862 cie
->segment_size
= read_1_byte (unit
->abfd
, buf
);
1867 cie
->addr_size
= gdbarch_dwarf2_addr_size (gdbarch
);
1868 cie
->segment_size
= 0;
1870 /* Address values in .eh_frame sections are defined to have the
1871 target's pointer size. Watchout: This breaks frame info for
1872 targets with pointer size < address size, unless a .debug_frame
1873 section exists as well. */
1875 cie
->ptr_size
= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1877 cie
->ptr_size
= cie
->addr_size
;
1879 buf
= gdb_read_uleb128 (buf
, end
, &uleb128
);
1882 cie
->code_alignment_factor
= uleb128
;
1884 buf
= gdb_read_sleb128 (buf
, end
, &sleb128
);
1887 cie
->data_alignment_factor
= sleb128
;
1889 if (cie_version
== 1)
1891 cie
->return_address_register
= read_1_byte (unit
->abfd
, buf
);
1896 buf
= gdb_read_uleb128 (buf
, end
, &uleb128
);
1899 cie
->return_address_register
= uleb128
;
1902 cie
->return_address_register
1903 = dwarf2_frame_adjust_regnum (gdbarch
,
1904 cie
->return_address_register
,
1907 cie
->saw_z_augmentation
= (*augmentation
== 'z');
1908 if (cie
->saw_z_augmentation
)
1910 uint64_t uleb_length
;
1912 buf
= gdb_read_uleb128 (buf
, end
, &uleb_length
);
1915 cie
->initial_instructions
= buf
+ uleb_length
;
1919 while (*augmentation
)
1921 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1922 if (*augmentation
== 'L')
1929 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1930 else if (*augmentation
== 'R')
1932 cie
->encoding
= *buf
++;
1936 /* "P" indicates a personality routine in the CIE augmentation. */
1937 else if (*augmentation
== 'P')
1939 /* Skip. Avoid indirection since we throw away the result. */
1940 gdb_byte encoding
= (*buf
++) & ~DW_EH_PE_indirect
;
1941 read_encoded_value (unit
, encoding
, cie
->ptr_size
,
1942 buf
, &bytes_read
, 0);
1947 /* "S" indicates a signal frame, such that the return
1948 address must not be decremented to locate the call frame
1949 info for the previous frame; it might even be the first
1950 instruction of a function, so decrementing it would take
1951 us to a different function. */
1952 else if (*augmentation
== 'S')
1954 cie
->signal_frame
= 1;
1958 /* Otherwise we have an unknown augmentation. Assume that either
1959 there is no augmentation data, or we saw a 'z' prefix. */
1962 if (cie
->initial_instructions
)
1963 buf
= cie
->initial_instructions
;
1968 cie
->initial_instructions
= buf
;
1972 cie_table
[cie
->cie_pointer
] = cie
;
1976 /* This is a FDE. */
1977 struct dwarf2_fde
*fde
;
1980 /* Check that an FDE was expected. */
1981 if ((entry_type
& EH_FDE_TYPE_ID
) == 0)
1982 error (_("Found an FDE when not expecting it."));
1984 /* In an .eh_frame section, the CIE pointer is the delta between the
1985 address within the FDE where the CIE pointer is stored and the
1986 address of the CIE. Convert it to an offset into the .eh_frame
1990 cie_pointer
= buf
- unit
->dwarf_frame_buffer
- cie_pointer
;
1991 cie_pointer
-= (dwarf64_p
? 8 : 4);
1994 /* In either case, validate the result is still within the section. */
1995 if (cie_pointer
>= unit
->dwarf_frame_size
)
1998 fde
= XOBNEW (&unit
->objfile
->objfile_obstack
, struct dwarf2_fde
);
1999 fde
->cie
= find_cie (cie_table
, cie_pointer
);
2000 if (fde
->cie
== NULL
)
2002 decode_frame_entry (unit
, unit
->dwarf_frame_buffer
+ cie_pointer
,
2003 eh_frame_p
, cie_table
, fde_table
,
2005 fde
->cie
= find_cie (cie_table
, cie_pointer
);
2008 gdb_assert (fde
->cie
!= NULL
);
2010 addr
= read_encoded_value (unit
, fde
->cie
->encoding
, fde
->cie
->ptr_size
,
2011 buf
, &bytes_read
, 0);
2012 fde
->initial_location
= gdbarch_adjust_dwarf2_addr (gdbarch
, addr
);
2015 fde
->address_range
=
2016 read_encoded_value (unit
, fde
->cie
->encoding
& 0x0f,
2017 fde
->cie
->ptr_size
, buf
, &bytes_read
, 0);
2018 addr
= gdbarch_adjust_dwarf2_addr (gdbarch
, addr
+ fde
->address_range
);
2019 fde
->address_range
= addr
- fde
->initial_location
;
2022 /* A 'z' augmentation in the CIE implies the presence of an
2023 augmentation field in the FDE as well. The only thing known
2024 to be in here at present is the LSDA entry for EH. So we
2025 can skip the whole thing. */
2026 if (fde
->cie
->saw_z_augmentation
)
2028 uint64_t uleb_length
;
2030 buf
= gdb_read_uleb128 (buf
, end
, &uleb_length
);
2038 fde
->instructions
= buf
;
2041 fde
->eh_frame_p
= eh_frame_p
;
2043 add_fde (fde_table
, fde
);
2049 /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
2050 expect an FDE or a CIE. */
2052 static const gdb_byte
*
2053 decode_frame_entry (struct comp_unit
*unit
, const gdb_byte
*start
,
2055 dwarf2_cie_table
&cie_table
,
2056 struct dwarf2_fde_table
*fde_table
,
2057 enum eh_frame_type entry_type
)
2059 enum { NONE
, ALIGN4
, ALIGN8
, FAIL
} workaround
= NONE
;
2060 const gdb_byte
*ret
;
2061 ptrdiff_t start_offset
;
2065 ret
= decode_frame_entry_1 (unit
, start
, eh_frame_p
,
2066 cie_table
, fde_table
, entry_type
);
2070 /* We have corrupt input data of some form. */
2072 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
2073 and mismatches wrt padding and alignment of debug sections. */
2074 /* Note that there is no requirement in the standard for any
2075 alignment at all in the frame unwind sections. Testing for
2076 alignment before trying to interpret data would be incorrect.
2078 However, GCC traditionally arranged for frame sections to be
2079 sized such that the FDE length and CIE fields happen to be
2080 aligned (in theory, for performance). This, unfortunately,
2081 was done with .align directives, which had the side effect of
2082 forcing the section to be aligned by the linker.
2084 This becomes a problem when you have some other producer that
2085 creates frame sections that are not as strictly aligned. That
2086 produces a hole in the frame info that gets filled by the
2089 The GCC behaviour is arguably a bug, but it's effectively now
2090 part of the ABI, so we're now stuck with it, at least at the
2091 object file level. A smart linker may decide, in the process
2092 of compressing duplicate CIE information, that it can rewrite
2093 the entire output section without this extra padding. */
2095 start_offset
= start
- unit
->dwarf_frame_buffer
;
2096 if (workaround
< ALIGN4
&& (start_offset
& 3) != 0)
2098 start
+= 4 - (start_offset
& 3);
2099 workaround
= ALIGN4
;
2102 if (workaround
< ALIGN8
&& (start_offset
& 7) != 0)
2104 start
+= 8 - (start_offset
& 7);
2105 workaround
= ALIGN8
;
2109 /* Nothing left to try. Arrange to return as if we've consumed
2110 the entire input section. Hopefully we'll get valid info from
2111 the other of .debug_frame/.eh_frame. */
2113 ret
= unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
;
2124 Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
2125 unit
->dwarf_frame_section
->owner
->filename
,
2126 unit
->dwarf_frame_section
->name
);
2131 Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
2132 unit
->dwarf_frame_section
->owner
->filename
,
2133 unit
->dwarf_frame_section
->name
);
2137 complaint (_("Corrupt data in %s:%s"),
2138 unit
->dwarf_frame_section
->owner
->filename
,
2139 unit
->dwarf_frame_section
->name
);
2147 fde_is_less_than (const dwarf2_fde
*aa
, const dwarf2_fde
*bb
)
2149 if (aa
->initial_location
== bb
->initial_location
)
2151 if (aa
->address_range
!= bb
->address_range
2152 && aa
->eh_frame_p
== 0 && bb
->eh_frame_p
== 0)
2153 /* Linker bug, e.g. gold/10400.
2154 Work around it by keeping stable sort order. */
2157 /* Put eh_frame entries after debug_frame ones. */
2158 return aa
->eh_frame_p
< bb
->eh_frame_p
;
2161 return aa
->initial_location
< bb
->initial_location
;
2165 dwarf2_build_frame_info (struct objfile
*objfile
)
2167 struct comp_unit
*unit
;
2168 const gdb_byte
*frame_ptr
;
2169 dwarf2_cie_table cie_table
;
2170 struct dwarf2_fde_table fde_table
;
2171 struct dwarf2_fde_table
*fde_table2
;
2173 fde_table
.num_entries
= 0;
2174 fde_table
.entries
= NULL
;
2176 /* Build a minimal decoding of the DWARF2 compilation unit. */
2177 unit
= XOBNEW (&objfile
->objfile_obstack
, comp_unit
);
2178 unit
->abfd
= objfile
->obfd
;
2179 unit
->objfile
= objfile
;
2183 if (objfile
->separate_debug_objfile_backlink
== NULL
)
2185 /* Do not read .eh_frame from separate file as they must be also
2186 present in the main file. */
2187 dwarf2_get_section_info (objfile
, DWARF2_EH_FRAME
,
2188 &unit
->dwarf_frame_section
,
2189 &unit
->dwarf_frame_buffer
,
2190 &unit
->dwarf_frame_size
);
2191 if (unit
->dwarf_frame_size
)
2193 asection
*got
, *txt
;
2195 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2196 that is used for the i386/amd64 target, which currently is
2197 the only target in GCC that supports/uses the
2198 DW_EH_PE_datarel encoding. */
2199 got
= bfd_get_section_by_name (unit
->abfd
, ".got");
2201 unit
->dbase
= got
->vma
;
2203 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2205 txt
= bfd_get_section_by_name (unit
->abfd
, ".text");
2207 unit
->tbase
= txt
->vma
;
2211 frame_ptr
= unit
->dwarf_frame_buffer
;
2212 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2213 frame_ptr
= decode_frame_entry (unit
, frame_ptr
, 1,
2214 cie_table
, &fde_table
,
2215 EH_CIE_OR_FDE_TYPE_ID
);
2218 catch (const gdb_exception_error
&e
)
2220 warning (_("skipping .eh_frame info of %s: %s"),
2221 objfile_name (objfile
), e
.what ());
2223 if (fde_table
.num_entries
!= 0)
2225 xfree (fde_table
.entries
);
2226 fde_table
.entries
= NULL
;
2227 fde_table
.num_entries
= 0;
2229 /* The cie_table is discarded below. */
2236 dwarf2_get_section_info (objfile
, DWARF2_DEBUG_FRAME
,
2237 &unit
->dwarf_frame_section
,
2238 &unit
->dwarf_frame_buffer
,
2239 &unit
->dwarf_frame_size
);
2240 if (unit
->dwarf_frame_size
)
2242 int num_old_fde_entries
= fde_table
.num_entries
;
2246 frame_ptr
= unit
->dwarf_frame_buffer
;
2247 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2248 frame_ptr
= decode_frame_entry (unit
, frame_ptr
, 0,
2249 cie_table
, &fde_table
,
2250 EH_CIE_OR_FDE_TYPE_ID
);
2252 catch (const gdb_exception_error
&e
)
2254 warning (_("skipping .debug_frame info of %s: %s"),
2255 objfile_name (objfile
), e
.what ());
2257 if (fde_table
.num_entries
!= 0)
2259 fde_table
.num_entries
= num_old_fde_entries
;
2260 if (num_old_fde_entries
== 0)
2262 xfree (fde_table
.entries
);
2263 fde_table
.entries
= NULL
;
2268 = XRESIZEVEC (struct dwarf2_fde
*, fde_table
.entries
,
2269 fde_table
.num_entries
);
2272 fde_table
.num_entries
= num_old_fde_entries
;
2276 /* Copy fde_table to obstack: it is needed at runtime. */
2277 fde_table2
= XOBNEW (&objfile
->objfile_obstack
, struct dwarf2_fde_table
);
2279 if (fde_table
.num_entries
== 0)
2281 fde_table2
->entries
= NULL
;
2282 fde_table2
->num_entries
= 0;
2286 struct dwarf2_fde
*fde_prev
= NULL
;
2287 struct dwarf2_fde
*first_non_zero_fde
= NULL
;
2290 /* Prepare FDE table for lookups. */
2291 std::sort (fde_table
.entries
, fde_table
.entries
+ fde_table
.num_entries
,
2294 /* Check for leftovers from --gc-sections. The GNU linker sets
2295 the relevant symbols to zero, but doesn't zero the FDE *end*
2296 ranges because there's no relocation there. It's (offset,
2297 length), not (start, end). On targets where address zero is
2298 just another valid address this can be a problem, since the
2299 FDEs appear to be non-empty in the output --- we could pick
2300 out the wrong FDE. To work around this, when overlaps are
2301 detected, we prefer FDEs that do not start at zero.
2303 Start by finding the first FDE with non-zero start. Below
2304 we'll discard all FDEs that start at zero and overlap this
2306 for (i
= 0; i
< fde_table
.num_entries
; i
++)
2308 struct dwarf2_fde
*fde
= fde_table
.entries
[i
];
2310 if (fde
->initial_location
!= 0)
2312 first_non_zero_fde
= fde
;
2317 /* Since we'll be doing bsearch, squeeze out identical (except
2318 for eh_frame_p) fde entries so bsearch result is predictable.
2319 Also discard leftovers from --gc-sections. */
2320 fde_table2
->num_entries
= 0;
2321 for (i
= 0; i
< fde_table
.num_entries
; i
++)
2323 struct dwarf2_fde
*fde
= fde_table
.entries
[i
];
2325 if (fde
->initial_location
== 0
2326 && first_non_zero_fde
!= NULL
2327 && (first_non_zero_fde
->initial_location
2328 < fde
->initial_location
+ fde
->address_range
))
2331 if (fde_prev
!= NULL
2332 && fde_prev
->initial_location
== fde
->initial_location
)
2335 obstack_grow (&objfile
->objfile_obstack
, &fde_table
.entries
[i
],
2336 sizeof (fde_table
.entries
[0]));
2337 ++fde_table2
->num_entries
;
2341 = (struct dwarf2_fde
**) obstack_finish (&objfile
->objfile_obstack
);
2343 /* Discard the original fde_table. */
2344 xfree (fde_table
.entries
);
2347 dwarf2_frame_objfile_data
.set (objfile
, fde_table2
);
2350 /* Handle 'maintenance show dwarf unwinders'. */
2353 show_dwarf_unwinders_enabled_p (struct ui_file
*file
, int from_tty
,
2354 struct cmd_list_element
*c
,
2357 fprintf_filtered (file
,
2358 _("The DWARF stack unwinders are currently %s.\n"),
2363 _initialize_dwarf2_frame (void)
2365 dwarf2_frame_data
= gdbarch_data_register_pre_init (dwarf2_frame_init
);
2367 add_setshow_boolean_cmd ("unwinders", class_obscure
,
2368 &dwarf2_frame_unwinders_enabled_p
, _("\
2369 Set whether the DWARF stack frame unwinders are used."), _("\
2370 Show whether the DWARF stack frame unwinders are used."), _("\
2371 When enabled the DWARF stack frame unwinders can be used for architectures\n\
2372 that support the DWARF unwinders. Enabling the DWARF unwinders for an\n\
2373 architecture that doesn't support them will have no effect."),
2375 show_dwarf_unwinders_enabled_p
,
2377 &show_dwarf_cmdlist
);
2380 selftests::register_test_foreach_arch ("execute_cfa_program",
2381 selftests::execute_cfa_program_test
);