1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright (C) 2003-2020 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 "dwarf2/expr.h"
25 #include "dwarf2/leb.h"
27 #include "frame-base.h"
28 #include "frame-unwind.h"
37 #include "complaints.h"
38 #include "dwarf2/frame.h"
39 #include "dwarf2/read.h"
41 #include "dwarf2/loc.h"
42 #include "dwarf2/frame-tailcall.h"
43 #include "gdbsupport/gdb_binary_search.h"
45 #include "gdbsupport/selftest.h"
46 #include "selftest-arch.h"
48 #include <unordered_map>
54 /* Call Frame Information (CFI). */
56 /* Common Information Entry (CIE). */
60 /* Computation Unit for this CIE. */
61 struct comp_unit
*unit
;
63 /* Offset into the .debug_frame section where this CIE was found.
64 Used to identify this CIE. */
67 /* Constant that is factored out of all advance location
69 ULONGEST code_alignment_factor
;
71 /* Constants that is factored out of all offset instructions. */
72 LONGEST data_alignment_factor
;
74 /* Return address column. */
75 ULONGEST return_address_register
;
77 /* Instruction sequence to initialize a register set. */
78 const gdb_byte
*initial_instructions
;
81 /* Saved augmentation, in case it's needed later. */
84 /* Encoding of addresses. */
87 /* Target address size in bytes. */
90 /* Target pointer size in bytes. */
93 /* True if a 'z' augmentation existed. */
94 unsigned char saw_z_augmentation
;
96 /* True if an 'S' augmentation existed. */
97 unsigned char signal_frame
;
99 /* The version recorded in the CIE. */
100 unsigned char version
;
102 /* The segment size. */
103 unsigned char segment_size
;
106 /* The CIE table is used to find CIEs during parsing, but then
107 discarded. It maps from the CIE's offset to the CIE. */
108 typedef std::unordered_map
<ULONGEST
, dwarf2_cie
*> dwarf2_cie_table
;
110 /* Frame Description Entry (FDE). */
114 /* CIE for this FDE. */
115 struct dwarf2_cie
*cie
;
117 /* First location associated with this FDE. */
118 CORE_ADDR initial_location
;
120 /* Number of bytes of program instructions described by this FDE. */
121 CORE_ADDR address_range
;
123 /* Instruction sequence. */
124 const gdb_byte
*instructions
;
127 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
129 unsigned char eh_frame_p
;
132 typedef std::vector
<dwarf2_fde
*> dwarf2_fde_table
;
134 /* A minimal decoding of DWARF2 compilation units. We only decode
135 what's needed to get to the call frame information. */
139 comp_unit (struct objfile
*objf
)
144 /* Keep the bfd convenient. */
147 /* Pointer to the .debug_frame section loaded into memory. */
148 const gdb_byte
*dwarf_frame_buffer
= nullptr;
150 /* Length of the loaded .debug_frame section. */
151 bfd_size_type dwarf_frame_size
= 0;
153 /* Pointer to the .debug_frame section. */
154 asection
*dwarf_frame_section
= nullptr;
156 /* Base for DW_EH_PE_datarel encodings. */
159 /* Base for DW_EH_PE_textrel encodings. */
163 dwarf2_fde_table fde_table
;
165 /* Hold data used by this module. */
166 auto_obstack obstack
;
169 static struct dwarf2_fde
*dwarf2_frame_find_fde
170 (CORE_ADDR
*pc
, dwarf2_per_objfile
**out_per_objfile
);
172 static int dwarf2_frame_adjust_regnum (struct gdbarch
*gdbarch
, int regnum
,
175 static CORE_ADDR
read_encoded_value (struct comp_unit
*unit
, gdb_byte encoding
,
176 int ptr_len
, const gdb_byte
*buf
,
177 unsigned int *bytes_read_ptr
,
178 CORE_ADDR func_base
);
181 /* See dwarf2-frame.h. */
182 bool dwarf2_frame_unwinders_enabled_p
= true;
184 /* Store the length the expression for the CFA in the `cfa_reg' field,
185 which is unused in that case. */
186 #define cfa_exp_len cfa_reg
188 dwarf2_frame_state::dwarf2_frame_state (CORE_ADDR pc_
, struct dwarf2_cie
*cie
)
189 : pc (pc_
), data_align (cie
->data_alignment_factor
),
190 code_align (cie
->code_alignment_factor
),
191 retaddr_column (cie
->return_address_register
)
196 /* Helper functions for execute_stack_op. */
199 read_addr_from_reg (struct frame_info
*this_frame
, int reg
)
201 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
202 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, reg
);
204 return address_from_register (regnum
, this_frame
);
207 /* Execute the required actions for both the DW_CFA_restore and
208 DW_CFA_restore_extended instructions. */
210 dwarf2_restore_rule (struct gdbarch
*gdbarch
, ULONGEST reg_num
,
211 struct dwarf2_frame_state
*fs
, int eh_frame_p
)
215 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg_num
, eh_frame_p
);
216 fs
->regs
.alloc_regs (reg
+ 1);
218 /* Check if this register was explicitly initialized in the
219 CIE initial instructions. If not, default the rule to
221 if (reg
< fs
->initial
.reg
.size ())
222 fs
->regs
.reg
[reg
] = fs
->initial
.reg
[reg
];
224 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNSPECIFIED
;
226 if (fs
->regs
.reg
[reg
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
228 int regnum
= dwarf_reg_to_regnum (gdbarch
, reg
);
231 incomplete CFI data; DW_CFA_restore unspecified\n\
232 register %s (#%d) at %s"),
233 gdbarch_register_name (gdbarch
, regnum
), regnum
,
234 paddress (gdbarch
, fs
->pc
));
238 class dwarf_expr_executor
: public dwarf_expr_context
242 dwarf_expr_executor (dwarf2_per_objfile
*per_objfile
)
243 : dwarf_expr_context (per_objfile
)
246 struct frame_info
*this_frame
;
248 CORE_ADDR
read_addr_from_reg (int reg
) override
250 return ::read_addr_from_reg (this_frame
, reg
);
253 struct value
*get_reg_value (struct type
*type
, int reg
) override
255 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
256 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, reg
);
258 return value_from_register (type
, regnum
, this_frame
);
261 void read_mem (gdb_byte
*buf
, CORE_ADDR addr
, size_t len
) override
263 read_memory (addr
, buf
, len
);
266 void get_frame_base (const gdb_byte
**start
, size_t *length
) override
268 invalid ("DW_OP_fbreg");
271 void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind
,
272 union call_site_parameter_u kind_u
,
273 int deref_size
) override
275 invalid ("DW_OP_entry_value");
278 CORE_ADDR
get_object_address () override
280 invalid ("DW_OP_push_object_address");
283 CORE_ADDR
get_frame_cfa () override
285 invalid ("DW_OP_call_frame_cfa");
288 CORE_ADDR
get_tls_address (CORE_ADDR offset
) override
290 invalid ("DW_OP_form_tls_address");
293 void dwarf_call (cu_offset die_offset
) override
295 invalid ("DW_OP_call*");
298 struct value
*dwarf_variable_value (sect_offset sect_off
) override
300 invalid ("DW_OP_GNU_variable_value");
303 CORE_ADDR
get_addr_index (unsigned int index
) override
305 invalid ("DW_OP_addrx or DW_OP_GNU_addr_index");
310 void invalid (const char *op
) ATTRIBUTE_NORETURN
312 error (_("%s is invalid in this context"), op
);
317 execute_stack_op (const gdb_byte
*exp
, ULONGEST len
, int addr_size
,
318 struct frame_info
*this_frame
, CORE_ADDR initial
,
319 int initial_in_stack_memory
, dwarf2_per_objfile
*per_objfile
)
323 dwarf_expr_executor
ctx (per_objfile
);
324 scoped_value_mark free_values
;
326 ctx
.this_frame
= this_frame
;
327 ctx
.gdbarch
= get_frame_arch (this_frame
);
328 ctx
.addr_size
= addr_size
;
329 ctx
.ref_addr_size
= -1;
331 ctx
.push_address (initial
, initial_in_stack_memory
);
334 if (ctx
.location
== DWARF_VALUE_MEMORY
)
335 result
= ctx
.fetch_address (0);
336 else if (ctx
.location
== DWARF_VALUE_REGISTER
)
337 result
= ctx
.read_addr_from_reg (value_as_long (ctx
.fetch (0)));
340 /* This is actually invalid DWARF, but if we ever do run across
341 it somehow, we might as well support it. So, instead, report
342 it as unimplemented. */
344 Not implemented: computing unwound register using explicit value operator"));
351 /* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior
352 PC. Modify FS state accordingly. Return current INSN_PTR where the
353 execution has stopped, one can resume it on the next call. */
355 static const gdb_byte
*
356 execute_cfa_program (struct dwarf2_fde
*fde
, const gdb_byte
*insn_ptr
,
357 const gdb_byte
*insn_end
, struct gdbarch
*gdbarch
,
358 CORE_ADDR pc
, struct dwarf2_frame_state
*fs
,
359 CORE_ADDR text_offset
)
361 int eh_frame_p
= fde
->eh_frame_p
;
362 unsigned int bytes_read
;
363 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
365 while (insn_ptr
< insn_end
&& fs
->pc
<= pc
)
367 gdb_byte insn
= *insn_ptr
++;
371 if ((insn
& 0xc0) == DW_CFA_advance_loc
)
372 fs
->pc
+= (insn
& 0x3f) * fs
->code_align
;
373 else if ((insn
& 0xc0) == DW_CFA_offset
)
376 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
377 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
378 offset
= utmp
* fs
->data_align
;
379 fs
->regs
.alloc_regs (reg
+ 1);
380 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
381 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
383 else if ((insn
& 0xc0) == DW_CFA_restore
)
386 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
393 fs
->pc
= read_encoded_value (fde
->cie
->unit
, fde
->cie
->encoding
,
394 fde
->cie
->ptr_size
, insn_ptr
,
395 &bytes_read
, fde
->initial_location
);
396 /* Apply the text offset for relocatable objects. */
397 fs
->pc
+= text_offset
;
398 insn_ptr
+= bytes_read
;
401 case DW_CFA_advance_loc1
:
402 utmp
= extract_unsigned_integer (insn_ptr
, 1, byte_order
);
403 fs
->pc
+= utmp
* fs
->code_align
;
406 case DW_CFA_advance_loc2
:
407 utmp
= extract_unsigned_integer (insn_ptr
, 2, byte_order
);
408 fs
->pc
+= utmp
* fs
->code_align
;
411 case DW_CFA_advance_loc4
:
412 utmp
= extract_unsigned_integer (insn_ptr
, 4, byte_order
);
413 fs
->pc
+= utmp
* fs
->code_align
;
417 case DW_CFA_offset_extended
:
418 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
419 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
420 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
421 offset
= utmp
* fs
->data_align
;
422 fs
->regs
.alloc_regs (reg
+ 1);
423 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
424 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
427 case DW_CFA_restore_extended
:
428 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
429 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
432 case DW_CFA_undefined
:
433 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
434 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
435 fs
->regs
.alloc_regs (reg
+ 1);
436 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNDEFINED
;
439 case DW_CFA_same_value
:
440 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
441 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
442 fs
->regs
.alloc_regs (reg
+ 1);
443 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAME_VALUE
;
446 case DW_CFA_register
:
447 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
448 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
449 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
450 utmp
= dwarf2_frame_adjust_regnum (gdbarch
, utmp
, eh_frame_p
);
451 fs
->regs
.alloc_regs (reg
+ 1);
452 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_REG
;
453 fs
->regs
.reg
[reg
].loc
.reg
= utmp
;
456 case DW_CFA_remember_state
:
458 struct dwarf2_frame_state_reg_info
*new_rs
;
460 new_rs
= new dwarf2_frame_state_reg_info (fs
->regs
);
461 fs
->regs
.prev
= new_rs
;
465 case DW_CFA_restore_state
:
467 struct dwarf2_frame_state_reg_info
*old_rs
= fs
->regs
.prev
;
472 bad CFI data; mismatched DW_CFA_restore_state at %s"),
473 paddress (gdbarch
, fs
->pc
));
476 fs
->regs
= std::move (*old_rs
);
481 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
482 fs
->regs
.cfa_reg
= reg
;
483 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
485 if (fs
->armcc_cfa_offsets_sf
)
486 utmp
*= fs
->data_align
;
488 fs
->regs
.cfa_offset
= utmp
;
489 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
492 case DW_CFA_def_cfa_register
:
493 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
494 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
,
496 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
499 case DW_CFA_def_cfa_offset
:
500 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
502 if (fs
->armcc_cfa_offsets_sf
)
503 utmp
*= fs
->data_align
;
505 fs
->regs
.cfa_offset
= utmp
;
506 /* cfa_how deliberately not set. */
512 case DW_CFA_def_cfa_expression
:
513 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
514 fs
->regs
.cfa_exp_len
= utmp
;
515 fs
->regs
.cfa_exp
= insn_ptr
;
516 fs
->regs
.cfa_how
= CFA_EXP
;
517 insn_ptr
+= fs
->regs
.cfa_exp_len
;
520 case DW_CFA_expression
:
521 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
522 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
523 fs
->regs
.alloc_regs (reg
+ 1);
524 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
525 fs
->regs
.reg
[reg
].loc
.exp
.start
= insn_ptr
;
526 fs
->regs
.reg
[reg
].loc
.exp
.len
= utmp
;
527 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_EXP
;
531 case DW_CFA_offset_extended_sf
:
532 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
533 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
534 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
535 offset
*= fs
->data_align
;
536 fs
->regs
.alloc_regs (reg
+ 1);
537 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
538 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
541 case DW_CFA_val_offset
:
542 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
543 fs
->regs
.alloc_regs (reg
+ 1);
544 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
545 offset
= utmp
* fs
->data_align
;
546 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_OFFSET
;
547 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
550 case DW_CFA_val_offset_sf
:
551 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
552 fs
->regs
.alloc_regs (reg
+ 1);
553 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
554 offset
*= fs
->data_align
;
555 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_OFFSET
;
556 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
559 case DW_CFA_val_expression
:
560 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
561 fs
->regs
.alloc_regs (reg
+ 1);
562 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
563 fs
->regs
.reg
[reg
].loc
.exp
.start
= insn_ptr
;
564 fs
->regs
.reg
[reg
].loc
.exp
.len
= utmp
;
565 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_EXP
;
569 case DW_CFA_def_cfa_sf
:
570 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
571 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
,
573 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
574 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
575 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
578 case DW_CFA_def_cfa_offset_sf
:
579 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
580 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
581 /* cfa_how deliberately not set. */
584 case DW_CFA_GNU_args_size
:
586 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
589 case DW_CFA_GNU_negative_offset_extended
:
590 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
591 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
592 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
593 offset
= utmp
* fs
->data_align
;
594 fs
->regs
.alloc_regs (reg
+ 1);
595 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
596 fs
->regs
.reg
[reg
].loc
.offset
= -offset
;
600 if (insn
>= DW_CFA_lo_user
&& insn
<= DW_CFA_hi_user
)
602 /* Handle vendor-specific CFI for different architectures. */
603 if (!gdbarch_execute_dwarf_cfa_vendor_op (gdbarch
, insn
, fs
))
604 error (_("Call Frame Instruction op %d in vendor extension "
605 "space is not handled on this architecture."),
609 internal_error (__FILE__
, __LINE__
,
610 _("Unknown CFI encountered."));
615 if (fs
->initial
.reg
.empty ())
617 /* Don't allow remember/restore between CIE and FDE programs. */
618 delete fs
->regs
.prev
;
619 fs
->regs
.prev
= NULL
;
627 namespace selftests
{
629 /* Unit test to function execute_cfa_program. */
632 execute_cfa_program_test (struct gdbarch
*gdbarch
)
634 struct dwarf2_fde fde
;
635 struct dwarf2_cie cie
;
637 memset (&fde
, 0, sizeof fde
);
638 memset (&cie
, 0, sizeof cie
);
640 cie
.data_alignment_factor
= -4;
641 cie
.code_alignment_factor
= 2;
644 dwarf2_frame_state
fs (0, fde
.cie
);
648 DW_CFA_def_cfa
, 1, 4, /* DW_CFA_def_cfa: r1 ofs 4 */
649 DW_CFA_offset
| 0x2, 1, /* DW_CFA_offset: r2 at cfa-4 */
650 DW_CFA_remember_state
,
651 DW_CFA_restore_state
,
654 const gdb_byte
*insn_end
= insns
+ sizeof (insns
);
655 const gdb_byte
*out
= execute_cfa_program (&fde
, insns
, insn_end
, gdbarch
,
658 SELF_CHECK (out
== insn_end
);
659 SELF_CHECK (fs
.pc
== 0);
661 /* The instructions above only use r1 and r2, but the register numbers
662 used are adjusted by dwarf2_frame_adjust_regnum. */
663 auto r1
= dwarf2_frame_adjust_regnum (gdbarch
, 1, fde
.eh_frame_p
);
664 auto r2
= dwarf2_frame_adjust_regnum (gdbarch
, 2, fde
.eh_frame_p
);
666 SELF_CHECK (fs
.regs
.reg
.size () == (std::max (r1
, r2
) + 1));
668 SELF_CHECK (fs
.regs
.reg
[r2
].how
== DWARF2_FRAME_REG_SAVED_OFFSET
);
669 SELF_CHECK (fs
.regs
.reg
[r2
].loc
.offset
== -4);
671 for (auto i
= 0; i
< fs
.regs
.reg
.size (); i
++)
673 SELF_CHECK (fs
.regs
.reg
[i
].how
== DWARF2_FRAME_REG_UNSPECIFIED
);
675 SELF_CHECK (fs
.regs
.cfa_reg
== 1);
676 SELF_CHECK (fs
.regs
.cfa_offset
== 4);
677 SELF_CHECK (fs
.regs
.cfa_how
== CFA_REG_OFFSET
);
678 SELF_CHECK (fs
.regs
.cfa_exp
== NULL
);
679 SELF_CHECK (fs
.regs
.prev
== NULL
);
682 } // namespace selftests
683 #endif /* GDB_SELF_TEST */
687 /* Architecture-specific operations. */
689 /* Per-architecture data key. */
690 static struct gdbarch_data
*dwarf2_frame_data
;
692 struct dwarf2_frame_ops
694 /* Pre-initialize the register state REG for register REGNUM. */
695 void (*init_reg
) (struct gdbarch
*, int, struct dwarf2_frame_state_reg
*,
696 struct frame_info
*);
698 /* Check whether the THIS_FRAME is a signal trampoline. */
699 int (*signal_frame_p
) (struct gdbarch
*, struct frame_info
*);
701 /* Convert .eh_frame register number to DWARF register number, or
702 adjust .debug_frame register number. */
703 int (*adjust_regnum
) (struct gdbarch
*, int, int);
706 /* Default architecture-specific register state initialization
710 dwarf2_frame_default_init_reg (struct gdbarch
*gdbarch
, int regnum
,
711 struct dwarf2_frame_state_reg
*reg
,
712 struct frame_info
*this_frame
)
714 /* If we have a register that acts as a program counter, mark it as
715 a destination for the return address. If we have a register that
716 serves as the stack pointer, arrange for it to be filled with the
717 call frame address (CFA). The other registers are marked as
720 We copy the return address to the program counter, since many
721 parts in GDB assume that it is possible to get the return address
722 by unwinding the program counter register. However, on ISA's
723 with a dedicated return address register, the CFI usually only
724 contains information to unwind that return address register.
726 The reason we're treating the stack pointer special here is
727 because in many cases GCC doesn't emit CFI for the stack pointer
728 and implicitly assumes that it is equal to the CFA. This makes
729 some sense since the DWARF specification (version 3, draft 8,
732 "Typically, the CFA is defined to be the value of the stack
733 pointer at the call site in the previous frame (which may be
734 different from its value on entry to the current frame)."
736 However, this isn't true for all platforms supported by GCC
737 (e.g. IBM S/390 and zSeries). Those architectures should provide
738 their own architecture-specific initialization function. */
740 if (regnum
== gdbarch_pc_regnum (gdbarch
))
741 reg
->how
= DWARF2_FRAME_REG_RA
;
742 else if (regnum
== gdbarch_sp_regnum (gdbarch
))
743 reg
->how
= DWARF2_FRAME_REG_CFA
;
746 /* Return a default for the architecture-specific operations. */
749 dwarf2_frame_init (struct obstack
*obstack
)
751 struct dwarf2_frame_ops
*ops
;
753 ops
= OBSTACK_ZALLOC (obstack
, struct dwarf2_frame_ops
);
754 ops
->init_reg
= dwarf2_frame_default_init_reg
;
758 /* Set the architecture-specific register state initialization
759 function for GDBARCH to INIT_REG. */
762 dwarf2_frame_set_init_reg (struct gdbarch
*gdbarch
,
763 void (*init_reg
) (struct gdbarch
*, int,
764 struct dwarf2_frame_state_reg
*,
765 struct frame_info
*))
767 struct dwarf2_frame_ops
*ops
768 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
770 ops
->init_reg
= init_reg
;
773 /* Pre-initialize the register state REG for register REGNUM. */
776 dwarf2_frame_init_reg (struct gdbarch
*gdbarch
, int regnum
,
777 struct dwarf2_frame_state_reg
*reg
,
778 struct frame_info
*this_frame
)
780 struct dwarf2_frame_ops
*ops
781 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
783 ops
->init_reg (gdbarch
, regnum
, reg
, this_frame
);
786 /* Set the architecture-specific signal trampoline recognition
787 function for GDBARCH to SIGNAL_FRAME_P. */
790 dwarf2_frame_set_signal_frame_p (struct gdbarch
*gdbarch
,
791 int (*signal_frame_p
) (struct gdbarch
*,
792 struct frame_info
*))
794 struct dwarf2_frame_ops
*ops
795 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
797 ops
->signal_frame_p
= signal_frame_p
;
800 /* Query the architecture-specific signal frame recognizer for
804 dwarf2_frame_signal_frame_p (struct gdbarch
*gdbarch
,
805 struct frame_info
*this_frame
)
807 struct dwarf2_frame_ops
*ops
808 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
810 if (ops
->signal_frame_p
== NULL
)
812 return ops
->signal_frame_p (gdbarch
, this_frame
);
815 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
819 dwarf2_frame_set_adjust_regnum (struct gdbarch
*gdbarch
,
820 int (*adjust_regnum
) (struct gdbarch
*,
823 struct dwarf2_frame_ops
*ops
824 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
826 ops
->adjust_regnum
= adjust_regnum
;
829 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
833 dwarf2_frame_adjust_regnum (struct gdbarch
*gdbarch
,
834 int regnum
, int eh_frame_p
)
836 struct dwarf2_frame_ops
*ops
837 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
839 if (ops
->adjust_regnum
== NULL
)
841 return ops
->adjust_regnum (gdbarch
, regnum
, eh_frame_p
);
845 dwarf2_frame_find_quirks (struct dwarf2_frame_state
*fs
,
846 struct dwarf2_fde
*fde
)
848 struct compunit_symtab
*cust
;
850 cust
= find_pc_compunit_symtab (fs
->pc
);
854 if (producer_is_realview (COMPUNIT_PRODUCER (cust
)))
856 if (fde
->cie
->version
== 1)
857 fs
->armcc_cfa_offsets_sf
= 1;
859 if (fde
->cie
->version
== 1)
860 fs
->armcc_cfa_offsets_reversed
= 1;
862 /* The reversed offset problem is present in some compilers
863 using DWARF3, but it was eventually fixed. Check the ARM
864 defined augmentations, which are in the format "armcc" followed
865 by a list of one-character options. The "+" option means
866 this problem is fixed (no quirk needed). If the armcc
867 augmentation is missing, the quirk is needed. */
868 if (fde
->cie
->version
== 3
869 && (!startswith (fde
->cie
->augmentation
, "armcc")
870 || strchr (fde
->cie
->augmentation
+ 5, '+') == NULL
))
871 fs
->armcc_cfa_offsets_reversed
= 1;
878 /* See dwarf2-frame.h. */
881 dwarf2_fetch_cfa_info (struct gdbarch
*gdbarch
, CORE_ADDR pc
,
882 struct dwarf2_per_cu_data
*data
,
883 int *regnum_out
, LONGEST
*offset_out
,
884 CORE_ADDR
*text_offset_out
,
885 const gdb_byte
**cfa_start_out
,
886 const gdb_byte
**cfa_end_out
)
888 struct dwarf2_fde
*fde
;
889 dwarf2_per_objfile
*per_objfile
;
892 /* Find the correct FDE. */
893 fde
= dwarf2_frame_find_fde (&pc1
, &per_objfile
);
895 error (_("Could not compute CFA; needed to translate this expression"));
897 gdb_assert (per_objfile
!= nullptr);
899 dwarf2_frame_state
fs (pc1
, fde
->cie
);
901 /* Check for "quirks" - known bugs in producers. */
902 dwarf2_frame_find_quirks (&fs
, fde
);
904 /* First decode all the insns in the CIE. */
905 execute_cfa_program (fde
, fde
->cie
->initial_instructions
,
906 fde
->cie
->end
, gdbarch
, pc
, &fs
,
907 per_objfile
->objfile
->text_section_offset ());
909 /* Save the initialized register set. */
910 fs
.initial
= fs
.regs
;
912 /* Then decode the insns in the FDE up to our target PC. */
913 execute_cfa_program (fde
, fde
->instructions
, fde
->end
, gdbarch
, pc
, &fs
,
914 per_objfile
->objfile
->text_section_offset ());
916 /* Calculate the CFA. */
917 switch (fs
.regs
.cfa_how
)
921 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, fs
.regs
.cfa_reg
);
923 *regnum_out
= regnum
;
924 if (fs
.armcc_cfa_offsets_reversed
)
925 *offset_out
= -fs
.regs
.cfa_offset
;
927 *offset_out
= fs
.regs
.cfa_offset
;
932 *text_offset_out
= per_objfile
->objfile
->text_section_offset ();
933 *cfa_start_out
= fs
.regs
.cfa_exp
;
934 *cfa_end_out
= fs
.regs
.cfa_exp
+ fs
.regs
.cfa_exp_len
;
938 internal_error (__FILE__
, __LINE__
, _("Unknown CFA rule."));
943 struct dwarf2_frame_cache
945 /* DWARF Call Frame Address. */
948 /* Set if the return address column was marked as unavailable
949 (required non-collected memory or registers to compute). */
950 int unavailable_retaddr
;
952 /* Set if the return address column was marked as undefined. */
953 int undefined_retaddr
;
955 /* Saved registers, indexed by GDB register number, not by DWARF
957 struct dwarf2_frame_state_reg
*reg
;
959 /* Return address register. */
960 struct dwarf2_frame_state_reg retaddr_reg
;
962 /* Target address size in bytes. */
965 /* The dwarf2_per_objfile from which this frame description came. */
966 dwarf2_per_objfile
*per_objfile
;
968 /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME
969 sequence. If NULL then it is a normal case with no TAILCALL_FRAME
970 involved. Non-bottom frames of a virtual tail call frames chain use
971 dwarf2_tailcall_frame_unwind unwinder so this field does not apply for
973 void *tailcall_cache
;
976 static struct dwarf2_frame_cache
*
977 dwarf2_frame_cache (struct frame_info
*this_frame
, void **this_cache
)
979 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
980 const int num_regs
= gdbarch_num_cooked_regs (gdbarch
);
981 struct dwarf2_frame_cache
*cache
;
982 struct dwarf2_fde
*fde
;
984 const gdb_byte
*instr
;
987 return (struct dwarf2_frame_cache
*) *this_cache
;
989 /* Allocate a new cache. */
990 cache
= FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache
);
991 cache
->reg
= FRAME_OBSTACK_CALLOC (num_regs
, struct dwarf2_frame_state_reg
);
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
->per_objfile
);
1013 gdb_assert (fde
!= NULL
);
1014 gdb_assert (cache
->per_objfile
!= nullptr);
1016 /* Allocate and initialize the frame state. */
1017 struct dwarf2_frame_state
fs (pc1
, fde
->cie
);
1019 cache
->addr_size
= fde
->cie
->addr_size
;
1021 /* Check for "quirks" - known bugs in producers. */
1022 dwarf2_frame_find_quirks (&fs
, fde
);
1024 /* First decode all the insns in the CIE. */
1025 execute_cfa_program (fde
, fde
->cie
->initial_instructions
,
1026 fde
->cie
->end
, gdbarch
,
1027 get_frame_address_in_block (this_frame
), &fs
,
1028 cache
->per_objfile
->objfile
->text_section_offset ());
1030 /* Save the initialized register set. */
1031 fs
.initial
= fs
.regs
;
1033 /* Fetching the entry pc for THIS_FRAME won't necessarily result
1034 in an address that's within the range of FDE locations. This
1035 is due to the possibility of the function occupying non-contiguous
1037 LONGEST entry_cfa_sp_offset
;
1038 int entry_cfa_sp_offset_p
= 0;
1039 if (get_frame_func_if_available (this_frame
, &entry_pc
)
1040 && fde
->initial_location
<= entry_pc
1041 && entry_pc
< fde
->initial_location
+ fde
->address_range
)
1043 /* Decode the insns in the FDE up to the entry PC. */
1044 instr
= execute_cfa_program
1045 (fde
, fde
->instructions
, fde
->end
, gdbarch
, entry_pc
, &fs
,
1046 cache
->per_objfile
->objfile
->text_section_offset ());
1048 if (fs
.regs
.cfa_how
== CFA_REG_OFFSET
1049 && (dwarf_reg_to_regnum (gdbarch
, fs
.regs
.cfa_reg
)
1050 == gdbarch_sp_regnum (gdbarch
)))
1052 entry_cfa_sp_offset
= fs
.regs
.cfa_offset
;
1053 entry_cfa_sp_offset_p
= 1;
1057 instr
= fde
->instructions
;
1059 /* Then decode the insns in the FDE up to our target PC. */
1060 execute_cfa_program (fde
, instr
, fde
->end
, gdbarch
,
1061 get_frame_address_in_block (this_frame
), &fs
,
1062 cache
->per_objfile
->objfile
->text_section_offset ());
1066 /* Calculate the CFA. */
1067 switch (fs
.regs
.cfa_how
)
1069 case CFA_REG_OFFSET
:
1070 cache
->cfa
= read_addr_from_reg (this_frame
, fs
.regs
.cfa_reg
);
1071 if (fs
.armcc_cfa_offsets_reversed
)
1072 cache
->cfa
-= fs
.regs
.cfa_offset
;
1074 cache
->cfa
+= fs
.regs
.cfa_offset
;
1079 execute_stack_op (fs
.regs
.cfa_exp
, fs
.regs
.cfa_exp_len
,
1080 cache
->addr_size
, this_frame
, 0, 0,
1081 cache
->per_objfile
);
1085 internal_error (__FILE__
, __LINE__
, _("Unknown CFA rule."));
1088 catch (const gdb_exception_error
&ex
)
1090 if (ex
.error
== NOT_AVAILABLE_ERROR
)
1092 cache
->unavailable_retaddr
= 1;
1099 /* Initialize the register state. */
1103 for (regnum
= 0; regnum
< num_regs
; regnum
++)
1104 dwarf2_frame_init_reg (gdbarch
, regnum
, &cache
->reg
[regnum
], this_frame
);
1107 /* Go through the DWARF2 CFI generated table and save its register
1108 location information in the cache. Note that we don't skip the
1109 return address column; it's perfectly all right for it to
1110 correspond to a real register. */
1112 int column
; /* CFI speak for "register number". */
1114 for (column
= 0; column
< fs
.regs
.reg
.size (); column
++)
1116 /* Use the GDB register number as the destination index. */
1117 int regnum
= dwarf_reg_to_regnum (gdbarch
, column
);
1119 /* Protect against a target returning a bad register. */
1120 if (regnum
< 0 || regnum
>= num_regs
)
1123 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1124 of all debug info registers. If it doesn't, complain (but
1125 not too loudly). It turns out that GCC assumes that an
1126 unspecified register implies "same value" when CFI (draft
1127 7) specifies nothing at all. Such a register could equally
1128 be interpreted as "undefined". Also note that this check
1129 isn't sufficient; it only checks that all registers in the
1130 range [0 .. max column] are specified, and won't detect
1131 problems when a debug info register falls outside of the
1132 table. We need a way of iterating through all the valid
1133 DWARF2 register numbers. */
1134 if (fs
.regs
.reg
[column
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
1136 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
1138 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1139 gdbarch_register_name (gdbarch
, regnum
),
1140 paddress (gdbarch
, fs
.pc
));
1143 cache
->reg
[regnum
] = fs
.regs
.reg
[column
];
1147 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1148 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1152 for (regnum
= 0; regnum
< num_regs
; regnum
++)
1154 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
1155 || cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA_OFFSET
)
1157 const std::vector
<struct dwarf2_frame_state_reg
> ®s
1159 ULONGEST retaddr_column
= fs
.retaddr_column
;
1161 /* It seems rather bizarre to specify an "empty" column as
1162 the return adress column. However, this is exactly
1163 what GCC does on some targets. It turns out that GCC
1164 assumes that the return address can be found in the
1165 register corresponding to the return address column.
1166 Incidentally, that's how we should treat a return
1167 address column specifying "same value" too. */
1168 if (fs
.retaddr_column
< fs
.regs
.reg
.size ()
1169 && regs
[retaddr_column
].how
!= DWARF2_FRAME_REG_UNSPECIFIED
1170 && regs
[retaddr_column
].how
!= DWARF2_FRAME_REG_SAME_VALUE
)
1172 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1173 cache
->reg
[regnum
] = regs
[retaddr_column
];
1175 cache
->retaddr_reg
= regs
[retaddr_column
];
1179 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1181 cache
->reg
[regnum
].loc
.reg
= fs
.retaddr_column
;
1182 cache
->reg
[regnum
].how
= DWARF2_FRAME_REG_SAVED_REG
;
1186 cache
->retaddr_reg
.loc
.reg
= fs
.retaddr_column
;
1187 cache
->retaddr_reg
.how
= DWARF2_FRAME_REG_SAVED_REG
;
1194 if (fs
.retaddr_column
< fs
.regs
.reg
.size ()
1195 && fs
.regs
.reg
[fs
.retaddr_column
].how
== DWARF2_FRAME_REG_UNDEFINED
)
1196 cache
->undefined_retaddr
= 1;
1198 dwarf2_tailcall_sniffer_first (this_frame
, &cache
->tailcall_cache
,
1199 (entry_cfa_sp_offset_p
1200 ? &entry_cfa_sp_offset
: NULL
));
1205 static enum unwind_stop_reason
1206 dwarf2_frame_unwind_stop_reason (struct frame_info
*this_frame
,
1209 struct dwarf2_frame_cache
*cache
1210 = dwarf2_frame_cache (this_frame
, this_cache
);
1212 if (cache
->unavailable_retaddr
)
1213 return UNWIND_UNAVAILABLE
;
1215 if (cache
->undefined_retaddr
)
1216 return UNWIND_OUTERMOST
;
1218 return UNWIND_NO_REASON
;
1222 dwarf2_frame_this_id (struct frame_info
*this_frame
, void **this_cache
,
1223 struct frame_id
*this_id
)
1225 struct dwarf2_frame_cache
*cache
=
1226 dwarf2_frame_cache (this_frame
, this_cache
);
1228 if (cache
->unavailable_retaddr
)
1229 (*this_id
) = frame_id_build_unavailable_stack (get_frame_func (this_frame
));
1230 else if (cache
->undefined_retaddr
)
1233 (*this_id
) = frame_id_build (cache
->cfa
, get_frame_func (this_frame
));
1236 static struct value
*
1237 dwarf2_frame_prev_register (struct frame_info
*this_frame
, void **this_cache
,
1240 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
1241 struct dwarf2_frame_cache
*cache
=
1242 dwarf2_frame_cache (this_frame
, this_cache
);
1246 /* Non-bottom frames of a virtual tail call frames chain use
1247 dwarf2_tailcall_frame_unwind unwinder so this code does not apply for
1248 them. If dwarf2_tailcall_prev_register_first does not have specific value
1249 unwind the register, tail call frames are assumed to have the register set
1250 of the top caller. */
1251 if (cache
->tailcall_cache
)
1255 val
= dwarf2_tailcall_prev_register_first (this_frame
,
1256 &cache
->tailcall_cache
,
1262 switch (cache
->reg
[regnum
].how
)
1264 case DWARF2_FRAME_REG_UNDEFINED
:
1265 /* If CFI explicitly specified that the value isn't defined,
1266 mark it as optimized away; the value isn't available. */
1267 return frame_unwind_got_optimized (this_frame
, regnum
);
1269 case DWARF2_FRAME_REG_SAVED_OFFSET
:
1270 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1271 return frame_unwind_got_memory (this_frame
, regnum
, addr
);
1273 case DWARF2_FRAME_REG_SAVED_REG
:
1274 realnum
= dwarf_reg_to_regnum_or_error
1275 (gdbarch
, cache
->reg
[regnum
].loc
.reg
);
1276 return frame_unwind_got_register (this_frame
, regnum
, realnum
);
1278 case DWARF2_FRAME_REG_SAVED_EXP
:
1279 addr
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
.start
,
1280 cache
->reg
[regnum
].loc
.exp
.len
,
1282 this_frame
, cache
->cfa
, 1,
1283 cache
->per_objfile
);
1284 return frame_unwind_got_memory (this_frame
, regnum
, addr
);
1286 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET
:
1287 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1288 return frame_unwind_got_constant (this_frame
, regnum
, addr
);
1290 case DWARF2_FRAME_REG_SAVED_VAL_EXP
:
1291 addr
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
.start
,
1292 cache
->reg
[regnum
].loc
.exp
.len
,
1294 this_frame
, cache
->cfa
, 1,
1295 cache
->per_objfile
);
1296 return frame_unwind_got_constant (this_frame
, regnum
, addr
);
1298 case DWARF2_FRAME_REG_UNSPECIFIED
:
1299 /* GCC, in its infinite wisdom decided to not provide unwind
1300 information for registers that are "same value". Since
1301 DWARF2 (3 draft 7) doesn't define such behavior, said
1302 registers are actually undefined (which is different to CFI
1303 "undefined"). Code above issues a complaint about this.
1304 Here just fudge the books, assume GCC, and that the value is
1305 more inner on the stack. */
1306 return frame_unwind_got_register (this_frame
, regnum
, regnum
);
1308 case DWARF2_FRAME_REG_SAME_VALUE
:
1309 return frame_unwind_got_register (this_frame
, regnum
, regnum
);
1311 case DWARF2_FRAME_REG_CFA
:
1312 return frame_unwind_got_address (this_frame
, regnum
, cache
->cfa
);
1314 case DWARF2_FRAME_REG_CFA_OFFSET
:
1315 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1316 return frame_unwind_got_address (this_frame
, regnum
, addr
);
1318 case DWARF2_FRAME_REG_RA_OFFSET
:
1319 addr
= cache
->reg
[regnum
].loc
.offset
;
1320 regnum
= dwarf_reg_to_regnum_or_error
1321 (gdbarch
, cache
->retaddr_reg
.loc
.reg
);
1322 addr
+= get_frame_register_unsigned (this_frame
, regnum
);
1323 return frame_unwind_got_address (this_frame
, regnum
, addr
);
1325 case DWARF2_FRAME_REG_FN
:
1326 return cache
->reg
[regnum
].loc
.fn (this_frame
, this_cache
, regnum
);
1329 internal_error (__FILE__
, __LINE__
, _("Unknown register rule."));
1333 /* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail
1334 call frames chain. */
1337 dwarf2_frame_dealloc_cache (struct frame_info
*self
, void *this_cache
)
1339 struct dwarf2_frame_cache
*cache
= dwarf2_frame_cache (self
, &this_cache
);
1341 if (cache
->tailcall_cache
)
1342 dwarf2_tailcall_frame_unwind
.dealloc_cache (self
, cache
->tailcall_cache
);
1346 dwarf2_frame_sniffer (const struct frame_unwind
*self
,
1347 struct frame_info
*this_frame
, void **this_cache
)
1349 if (!dwarf2_frame_unwinders_enabled_p
)
1352 /* Grab an address that is guaranteed to reside somewhere within the
1353 function. get_frame_pc(), with a no-return next function, can
1354 end up returning something past the end of this function's body.
1355 If the frame we're sniffing for is a signal frame whose start
1356 address is placed on the stack by the OS, its FDE must
1357 extend one byte before its start address or we could potentially
1358 select the FDE of the previous function. */
1359 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1360 struct dwarf2_fde
*fde
= dwarf2_frame_find_fde (&block_addr
, NULL
);
1365 /* On some targets, signal trampolines may have unwind information.
1366 We need to recognize them so that we set the frame type
1369 if (fde
->cie
->signal_frame
1370 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame
),
1372 return self
->type
== SIGTRAMP_FRAME
;
1374 if (self
->type
!= NORMAL_FRAME
)
1380 static const struct frame_unwind dwarf2_frame_unwind
=
1383 dwarf2_frame_unwind_stop_reason
,
1384 dwarf2_frame_this_id
,
1385 dwarf2_frame_prev_register
,
1387 dwarf2_frame_sniffer
,
1388 dwarf2_frame_dealloc_cache
1391 static const struct frame_unwind dwarf2_signal_frame_unwind
=
1394 dwarf2_frame_unwind_stop_reason
,
1395 dwarf2_frame_this_id
,
1396 dwarf2_frame_prev_register
,
1398 dwarf2_frame_sniffer
,
1400 /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */
1404 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1407 dwarf2_append_unwinders (struct gdbarch
*gdbarch
)
1409 frame_unwind_append_unwinder (gdbarch
, &dwarf2_frame_unwind
);
1410 frame_unwind_append_unwinder (gdbarch
, &dwarf2_signal_frame_unwind
);
1414 /* There is no explicitly defined relationship between the CFA and the
1415 location of frame's local variables and arguments/parameters.
1416 Therefore, frame base methods on this page should probably only be
1417 used as a last resort, just to avoid printing total garbage as a
1418 response to the "info frame" command. */
1421 dwarf2_frame_base_address (struct frame_info
*this_frame
, void **this_cache
)
1423 struct dwarf2_frame_cache
*cache
=
1424 dwarf2_frame_cache (this_frame
, this_cache
);
1429 static const struct frame_base dwarf2_frame_base
=
1431 &dwarf2_frame_unwind
,
1432 dwarf2_frame_base_address
,
1433 dwarf2_frame_base_address
,
1434 dwarf2_frame_base_address
1437 const struct frame_base
*
1438 dwarf2_frame_base_sniffer (struct frame_info
*this_frame
)
1440 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1442 if (dwarf2_frame_find_fde (&block_addr
, NULL
))
1443 return &dwarf2_frame_base
;
1448 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1449 the DWARF unwinder. This is used to implement
1450 DW_OP_call_frame_cfa. */
1453 dwarf2_frame_cfa (struct frame_info
*this_frame
)
1455 if (frame_unwinder_is (this_frame
, &record_btrace_tailcall_frame_unwind
)
1456 || frame_unwinder_is (this_frame
, &record_btrace_frame_unwind
))
1457 throw_error (NOT_AVAILABLE_ERROR
,
1458 _("cfa not available for record btrace target"));
1460 while (get_frame_type (this_frame
) == INLINE_FRAME
)
1461 this_frame
= get_prev_frame (this_frame
);
1462 if (get_frame_unwind_stop_reason (this_frame
) == UNWIND_UNAVAILABLE
)
1463 throw_error (NOT_AVAILABLE_ERROR
,
1464 _("can't compute CFA for this frame: "
1465 "required registers or memory are unavailable"));
1467 if (get_frame_id (this_frame
).stack_status
!= FID_STACK_VALID
)
1468 throw_error (NOT_AVAILABLE_ERROR
,
1469 _("can't compute CFA for this frame: "
1470 "frame base not available"));
1472 return get_frame_base (this_frame
);
1475 /* We store the frame data on the BFD. This is only done if it is
1476 independent of the address space and so can be shared. */
1477 static const struct bfd_key
<comp_unit
> dwarf2_frame_bfd_data
;
1479 /* If any BFD sections require relocations (note; really should be if
1480 any debug info requires relocations), then we store the frame data
1481 on the objfile instead, and do not share it. */
1482 const struct objfile_key
<comp_unit
> dwarf2_frame_objfile_data
;
1485 /* Pointer encoding helper functions. */
1487 /* GCC supports exception handling based on DWARF2 CFI. However, for
1488 technical reasons, it encodes addresses in its FDE's in a different
1489 way. Several "pointer encodings" are supported. The encoding
1490 that's used for a particular FDE is determined by the 'R'
1491 augmentation in the associated CIE. The argument of this
1492 augmentation is a single byte.
1494 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1495 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1496 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1497 address should be interpreted (absolute, relative to the current
1498 position in the FDE, ...). Bit 7, indicates that the address
1499 should be dereferenced. */
1502 encoding_for_size (unsigned int size
)
1507 return DW_EH_PE_udata2
;
1509 return DW_EH_PE_udata4
;
1511 return DW_EH_PE_udata8
;
1513 internal_error (__FILE__
, __LINE__
, _("Unsupported address size"));
1518 read_encoded_value (struct comp_unit
*unit
, gdb_byte encoding
,
1519 int ptr_len
, const gdb_byte
*buf
,
1520 unsigned int *bytes_read_ptr
,
1521 CORE_ADDR func_base
)
1526 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1528 if (encoding
& DW_EH_PE_indirect
)
1529 internal_error (__FILE__
, __LINE__
,
1530 _("Unsupported encoding: DW_EH_PE_indirect"));
1532 *bytes_read_ptr
= 0;
1534 switch (encoding
& 0x70)
1536 case DW_EH_PE_absptr
:
1539 case DW_EH_PE_pcrel
:
1540 base
= bfd_section_vma (unit
->dwarf_frame_section
);
1541 base
+= (buf
- unit
->dwarf_frame_buffer
);
1543 case DW_EH_PE_datarel
:
1546 case DW_EH_PE_textrel
:
1549 case DW_EH_PE_funcrel
:
1552 case DW_EH_PE_aligned
:
1554 offset
= buf
- unit
->dwarf_frame_buffer
;
1555 if ((offset
% ptr_len
) != 0)
1557 *bytes_read_ptr
= ptr_len
- (offset
% ptr_len
);
1558 buf
+= *bytes_read_ptr
;
1562 internal_error (__FILE__
, __LINE__
,
1563 _("Invalid or unsupported encoding"));
1566 if ((encoding
& 0x07) == 0x00)
1568 encoding
|= encoding_for_size (ptr_len
);
1569 if (bfd_get_sign_extend_vma (unit
->abfd
))
1570 encoding
|= DW_EH_PE_signed
;
1573 switch (encoding
& 0x0f)
1575 case DW_EH_PE_uleb128
:
1578 const gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1580 *bytes_read_ptr
+= safe_read_uleb128 (buf
, end_buf
, &value
) - buf
;
1581 return base
+ value
;
1583 case DW_EH_PE_udata2
:
1584 *bytes_read_ptr
+= 2;
1585 return (base
+ bfd_get_16 (unit
->abfd
, (bfd_byte
*) buf
));
1586 case DW_EH_PE_udata4
:
1587 *bytes_read_ptr
+= 4;
1588 return (base
+ bfd_get_32 (unit
->abfd
, (bfd_byte
*) buf
));
1589 case DW_EH_PE_udata8
:
1590 *bytes_read_ptr
+= 8;
1591 return (base
+ bfd_get_64 (unit
->abfd
, (bfd_byte
*) buf
));
1592 case DW_EH_PE_sleb128
:
1595 const gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1597 *bytes_read_ptr
+= safe_read_sleb128 (buf
, end_buf
, &value
) - buf
;
1598 return base
+ value
;
1600 case DW_EH_PE_sdata2
:
1601 *bytes_read_ptr
+= 2;
1602 return (base
+ bfd_get_signed_16 (unit
->abfd
, (bfd_byte
*) buf
));
1603 case DW_EH_PE_sdata4
:
1604 *bytes_read_ptr
+= 4;
1605 return (base
+ bfd_get_signed_32 (unit
->abfd
, (bfd_byte
*) buf
));
1606 case DW_EH_PE_sdata8
:
1607 *bytes_read_ptr
+= 8;
1608 return (base
+ bfd_get_signed_64 (unit
->abfd
, (bfd_byte
*) buf
));
1610 internal_error (__FILE__
, __LINE__
,
1611 _("Invalid or unsupported encoding"));
1616 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1617 static struct dwarf2_cie
*
1618 find_cie (const dwarf2_cie_table
&cie_table
, ULONGEST cie_pointer
)
1620 auto iter
= cie_table
.find (cie_pointer
);
1621 if (iter
!= cie_table
.end ())
1622 return iter
->second
;
1627 bsearch_fde_cmp (const dwarf2_fde
*fde
, CORE_ADDR seek_pc
)
1629 if (fde
->initial_location
+ fde
->address_range
<= seek_pc
)
1631 if (fde
->initial_location
<= seek_pc
)
1636 /* Find an existing comp_unit for an objfile, if any. */
1639 find_comp_unit (struct objfile
*objfile
)
1641 bfd
*abfd
= objfile
->obfd
;
1642 if (gdb_bfd_requires_relocations (abfd
))
1643 return dwarf2_frame_bfd_data
.get (abfd
);
1644 return dwarf2_frame_objfile_data
.get (objfile
);
1647 /* Store the comp_unit on OBJFILE, or the corresponding BFD, as
1651 set_comp_unit (struct objfile
*objfile
, struct comp_unit
*unit
)
1653 bfd
*abfd
= objfile
->obfd
;
1654 if (gdb_bfd_requires_relocations (abfd
))
1655 return dwarf2_frame_bfd_data
.set (abfd
, unit
);
1656 return dwarf2_frame_objfile_data
.set (objfile
, unit
);
1659 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1660 initial location associated with it into *PC. */
1662 static struct dwarf2_fde
*
1663 dwarf2_frame_find_fde (CORE_ADDR
*pc
, dwarf2_per_objfile
**out_per_objfile
)
1665 for (objfile
*objfile
: current_program_space
->objfiles ())
1670 comp_unit
*unit
= find_comp_unit (objfile
);
1673 dwarf2_build_frame_info (objfile
);
1674 unit
= find_comp_unit (objfile
);
1676 gdb_assert (unit
!= NULL
);
1678 dwarf2_fde_table
*fde_table
= &unit
->fde_table
;
1679 if (fde_table
->empty ())
1682 gdb_assert (!objfile
->section_offsets
.empty ());
1683 offset
= objfile
->text_section_offset ();
1685 gdb_assert (!fde_table
->empty ());
1686 if (*pc
< offset
+ (*fde_table
)[0]->initial_location
)
1689 seek_pc
= *pc
- offset
;
1690 auto it
= gdb::binary_search (fde_table
->begin (), fde_table
->end (),
1691 seek_pc
, bsearch_fde_cmp
);
1692 if (it
!= fde_table
->end ())
1694 *pc
= (*it
)->initial_location
+ offset
;
1695 if (out_per_objfile
!= nullptr)
1696 *out_per_objfile
= get_dwarf2_per_objfile (objfile
);
1704 /* Add FDE to FDE_TABLE. */
1706 add_fde (dwarf2_fde_table
*fde_table
, struct dwarf2_fde
*fde
)
1708 if (fde
->address_range
== 0)
1709 /* Discard useless FDEs. */
1712 fde_table
->push_back (fde
);
1715 #define DW64_CIE_ID 0xffffffffffffffffULL
1717 /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
1722 EH_CIE_TYPE_ID
= 1 << 0,
1723 EH_FDE_TYPE_ID
= 1 << 1,
1724 EH_CIE_OR_FDE_TYPE_ID
= EH_CIE_TYPE_ID
| EH_FDE_TYPE_ID
1727 static const gdb_byte
*decode_frame_entry (struct gdbarch
*gdbarch
,
1728 struct comp_unit
*unit
,
1729 const gdb_byte
*start
,
1731 dwarf2_cie_table
&cie_table
,
1732 dwarf2_fde_table
*fde_table
,
1733 enum eh_frame_type entry_type
);
1735 /* Decode the next CIE or FDE, entry_type specifies the expected type.
1736 Return NULL if invalid input, otherwise the next byte to be processed. */
1738 static const gdb_byte
*
1739 decode_frame_entry_1 (struct gdbarch
*gdbarch
,
1740 struct comp_unit
*unit
, const gdb_byte
*start
,
1742 dwarf2_cie_table
&cie_table
,
1743 dwarf2_fde_table
*fde_table
,
1744 enum eh_frame_type entry_type
)
1746 const gdb_byte
*buf
, *end
;
1748 unsigned int bytes_read
;
1751 ULONGEST cie_pointer
;
1756 length
= read_initial_length (unit
->abfd
, buf
, &bytes_read
, false);
1758 end
= buf
+ (size_t) length
;
1763 /* Are we still within the section? */
1764 if (end
<= buf
|| end
> unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
1767 /* Distinguish between 32 and 64-bit encoded frame info. */
1768 dwarf64_p
= (bytes_read
== 12);
1770 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1774 cie_id
= DW64_CIE_ID
;
1780 cie_pointer
= read_8_bytes (unit
->abfd
, buf
);
1785 cie_pointer
= read_4_bytes (unit
->abfd
, buf
);
1789 if (cie_pointer
== cie_id
)
1791 /* This is a CIE. */
1792 struct dwarf2_cie
*cie
;
1794 unsigned int cie_version
;
1796 /* Check that a CIE was expected. */
1797 if ((entry_type
& EH_CIE_TYPE_ID
) == 0)
1798 error (_("Found a CIE when not expecting it."));
1800 /* Record the offset into the .debug_frame section of this CIE. */
1801 cie_pointer
= start
- unit
->dwarf_frame_buffer
;
1803 /* Check whether we've already read it. */
1804 if (find_cie (cie_table
, cie_pointer
))
1807 cie
= XOBNEW (&unit
->obstack
, struct dwarf2_cie
);
1808 cie
->initial_instructions
= NULL
;
1809 cie
->cie_pointer
= cie_pointer
;
1811 /* The encoding for FDE's in a normal .debug_frame section
1812 depends on the target address size. */
1813 cie
->encoding
= DW_EH_PE_absptr
;
1815 /* We'll determine the final value later, but we need to
1816 initialize it conservatively. */
1817 cie
->signal_frame
= 0;
1819 /* Check version number. */
1820 cie_version
= read_1_byte (unit
->abfd
, buf
);
1821 if (cie_version
!= 1 && cie_version
!= 3 && cie_version
!= 4)
1823 cie
->version
= cie_version
;
1826 /* Interpret the interesting bits of the augmentation. */
1827 cie
->augmentation
= augmentation
= (char *) buf
;
1828 buf
+= (strlen (augmentation
) + 1);
1830 /* Ignore armcc augmentations. We only use them for quirks,
1831 and that doesn't happen until later. */
1832 if (startswith (augmentation
, "armcc"))
1833 augmentation
+= strlen (augmentation
);
1835 /* The GCC 2.x "eh" augmentation has a pointer immediately
1836 following the augmentation string, so it must be handled
1838 if (augmentation
[0] == 'e' && augmentation
[1] == 'h')
1841 buf
+= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1845 if (cie
->version
>= 4)
1847 /* FIXME: check that this is the same as from the CU header. */
1848 cie
->addr_size
= read_1_byte (unit
->abfd
, buf
);
1850 cie
->segment_size
= read_1_byte (unit
->abfd
, buf
);
1855 cie
->addr_size
= gdbarch_dwarf2_addr_size (gdbarch
);
1856 cie
->segment_size
= 0;
1858 /* Address values in .eh_frame sections are defined to have the
1859 target's pointer size. Watchout: This breaks frame info for
1860 targets with pointer size < address size, unless a .debug_frame
1861 section exists as well. */
1863 cie
->ptr_size
= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1865 cie
->ptr_size
= cie
->addr_size
;
1867 buf
= gdb_read_uleb128 (buf
, end
, &uleb128
);
1870 cie
->code_alignment_factor
= uleb128
;
1872 buf
= gdb_read_sleb128 (buf
, end
, &sleb128
);
1875 cie
->data_alignment_factor
= sleb128
;
1877 if (cie_version
== 1)
1879 cie
->return_address_register
= read_1_byte (unit
->abfd
, buf
);
1884 buf
= gdb_read_uleb128 (buf
, end
, &uleb128
);
1887 cie
->return_address_register
= uleb128
;
1890 cie
->return_address_register
1891 = dwarf2_frame_adjust_regnum (gdbarch
,
1892 cie
->return_address_register
,
1895 cie
->saw_z_augmentation
= (*augmentation
== 'z');
1896 if (cie
->saw_z_augmentation
)
1898 uint64_t uleb_length
;
1900 buf
= gdb_read_uleb128 (buf
, end
, &uleb_length
);
1903 cie
->initial_instructions
= buf
+ uleb_length
;
1907 while (*augmentation
)
1909 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1910 if (*augmentation
== 'L')
1917 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1918 else if (*augmentation
== 'R')
1920 cie
->encoding
= *buf
++;
1924 /* "P" indicates a personality routine in the CIE augmentation. */
1925 else if (*augmentation
== 'P')
1927 /* Skip. Avoid indirection since we throw away the result. */
1928 gdb_byte encoding
= (*buf
++) & ~DW_EH_PE_indirect
;
1929 read_encoded_value (unit
, encoding
, cie
->ptr_size
,
1930 buf
, &bytes_read
, 0);
1935 /* "S" indicates a signal frame, such that the return
1936 address must not be decremented to locate the call frame
1937 info for the previous frame; it might even be the first
1938 instruction of a function, so decrementing it would take
1939 us to a different function. */
1940 else if (*augmentation
== 'S')
1942 cie
->signal_frame
= 1;
1946 /* Otherwise we have an unknown augmentation. Assume that either
1947 there is no augmentation data, or we saw a 'z' prefix. */
1950 if (cie
->initial_instructions
)
1951 buf
= cie
->initial_instructions
;
1956 cie
->initial_instructions
= buf
;
1960 cie_table
[cie
->cie_pointer
] = cie
;
1964 /* This is a FDE. */
1965 struct dwarf2_fde
*fde
;
1968 /* Check that an FDE was expected. */
1969 if ((entry_type
& EH_FDE_TYPE_ID
) == 0)
1970 error (_("Found an FDE when not expecting it."));
1972 /* In an .eh_frame section, the CIE pointer is the delta between the
1973 address within the FDE where the CIE pointer is stored and the
1974 address of the CIE. Convert it to an offset into the .eh_frame
1978 cie_pointer
= buf
- unit
->dwarf_frame_buffer
- cie_pointer
;
1979 cie_pointer
-= (dwarf64_p
? 8 : 4);
1982 /* In either case, validate the result is still within the section. */
1983 if (cie_pointer
>= unit
->dwarf_frame_size
)
1986 fde
= XOBNEW (&unit
->obstack
, struct dwarf2_fde
);
1987 fde
->cie
= find_cie (cie_table
, cie_pointer
);
1988 if (fde
->cie
== NULL
)
1990 decode_frame_entry (gdbarch
, unit
,
1991 unit
->dwarf_frame_buffer
+ cie_pointer
,
1992 eh_frame_p
, cie_table
, fde_table
,
1994 fde
->cie
= find_cie (cie_table
, cie_pointer
);
1997 gdb_assert (fde
->cie
!= NULL
);
1999 addr
= read_encoded_value (unit
, fde
->cie
->encoding
, fde
->cie
->ptr_size
,
2000 buf
, &bytes_read
, 0);
2001 fde
->initial_location
= gdbarch_adjust_dwarf2_addr (gdbarch
, addr
);
2004 fde
->address_range
=
2005 read_encoded_value (unit
, fde
->cie
->encoding
& 0x0f,
2006 fde
->cie
->ptr_size
, buf
, &bytes_read
, 0);
2007 addr
= gdbarch_adjust_dwarf2_addr (gdbarch
, addr
+ fde
->address_range
);
2008 fde
->address_range
= addr
- fde
->initial_location
;
2011 /* A 'z' augmentation in the CIE implies the presence of an
2012 augmentation field in the FDE as well. The only thing known
2013 to be in here at present is the LSDA entry for EH. So we
2014 can skip the whole thing. */
2015 if (fde
->cie
->saw_z_augmentation
)
2017 uint64_t uleb_length
;
2019 buf
= gdb_read_uleb128 (buf
, end
, &uleb_length
);
2027 fde
->instructions
= buf
;
2030 fde
->eh_frame_p
= eh_frame_p
;
2032 add_fde (fde_table
, fde
);
2038 /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
2039 expect an FDE or a CIE. */
2041 static const gdb_byte
*
2042 decode_frame_entry (struct gdbarch
*gdbarch
,
2043 struct comp_unit
*unit
, const gdb_byte
*start
,
2045 dwarf2_cie_table
&cie_table
,
2046 dwarf2_fde_table
*fde_table
,
2047 enum eh_frame_type entry_type
)
2049 enum { NONE
, ALIGN4
, ALIGN8
, FAIL
} workaround
= NONE
;
2050 const gdb_byte
*ret
;
2051 ptrdiff_t start_offset
;
2055 ret
= decode_frame_entry_1 (gdbarch
, unit
, start
, eh_frame_p
,
2056 cie_table
, fde_table
, entry_type
);
2060 /* We have corrupt input data of some form. */
2062 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
2063 and mismatches wrt padding and alignment of debug sections. */
2064 /* Note that there is no requirement in the standard for any
2065 alignment at all in the frame unwind sections. Testing for
2066 alignment before trying to interpret data would be incorrect.
2068 However, GCC traditionally arranged for frame sections to be
2069 sized such that the FDE length and CIE fields happen to be
2070 aligned (in theory, for performance). This, unfortunately,
2071 was done with .align directives, which had the side effect of
2072 forcing the section to be aligned by the linker.
2074 This becomes a problem when you have some other producer that
2075 creates frame sections that are not as strictly aligned. That
2076 produces a hole in the frame info that gets filled by the
2079 The GCC behaviour is arguably a bug, but it's effectively now
2080 part of the ABI, so we're now stuck with it, at least at the
2081 object file level. A smart linker may decide, in the process
2082 of compressing duplicate CIE information, that it can rewrite
2083 the entire output section without this extra padding. */
2085 start_offset
= start
- unit
->dwarf_frame_buffer
;
2086 if (workaround
< ALIGN4
&& (start_offset
& 3) != 0)
2088 start
+= 4 - (start_offset
& 3);
2089 workaround
= ALIGN4
;
2092 if (workaround
< ALIGN8
&& (start_offset
& 7) != 0)
2094 start
+= 8 - (start_offset
& 7);
2095 workaround
= ALIGN8
;
2099 /* Nothing left to try. Arrange to return as if we've consumed
2100 the entire input section. Hopefully we'll get valid info from
2101 the other of .debug_frame/.eh_frame. */
2103 ret
= unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
;
2114 Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
2115 bfd_get_filename (unit
->dwarf_frame_section
->owner
),
2116 bfd_section_name (unit
->dwarf_frame_section
));
2121 Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
2122 bfd_get_filename (unit
->dwarf_frame_section
->owner
),
2123 bfd_section_name (unit
->dwarf_frame_section
));
2127 complaint (_("Corrupt data in %s:%s"),
2128 bfd_get_filename (unit
->dwarf_frame_section
->owner
),
2129 bfd_section_name (unit
->dwarf_frame_section
));
2137 fde_is_less_than (const dwarf2_fde
*aa
, const dwarf2_fde
*bb
)
2139 if (aa
->initial_location
== bb
->initial_location
)
2141 if (aa
->address_range
!= bb
->address_range
2142 && aa
->eh_frame_p
== 0 && bb
->eh_frame_p
== 0)
2143 /* Linker bug, e.g. gold/10400.
2144 Work around it by keeping stable sort order. */
2147 /* Put eh_frame entries after debug_frame ones. */
2148 return aa
->eh_frame_p
< bb
->eh_frame_p
;
2151 return aa
->initial_location
< bb
->initial_location
;
2155 dwarf2_build_frame_info (struct objfile
*objfile
)
2157 const gdb_byte
*frame_ptr
;
2158 dwarf2_cie_table cie_table
;
2159 dwarf2_fde_table fde_table
;
2161 struct gdbarch
*gdbarch
= objfile
->arch ();
2163 /* Build a minimal decoding of the DWARF2 compilation unit. */
2164 std::unique_ptr
<comp_unit
> unit (new comp_unit (objfile
));
2166 if (objfile
->separate_debug_objfile_backlink
== NULL
)
2168 /* Do not read .eh_frame from separate file as they must be also
2169 present in the main file. */
2170 dwarf2_get_section_info (objfile
, DWARF2_EH_FRAME
,
2171 &unit
->dwarf_frame_section
,
2172 &unit
->dwarf_frame_buffer
,
2173 &unit
->dwarf_frame_size
);
2174 if (unit
->dwarf_frame_size
)
2176 asection
*got
, *txt
;
2178 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2179 that is used for the i386/amd64 target, which currently is
2180 the only target in GCC that supports/uses the
2181 DW_EH_PE_datarel encoding. */
2182 got
= bfd_get_section_by_name (unit
->abfd
, ".got");
2184 unit
->dbase
= got
->vma
;
2186 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2188 txt
= bfd_get_section_by_name (unit
->abfd
, ".text");
2190 unit
->tbase
= txt
->vma
;
2194 frame_ptr
= unit
->dwarf_frame_buffer
;
2195 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2196 frame_ptr
= decode_frame_entry (gdbarch
, unit
.get (),
2198 cie_table
, &fde_table
,
2199 EH_CIE_OR_FDE_TYPE_ID
);
2202 catch (const gdb_exception_error
&e
)
2204 warning (_("skipping .eh_frame info of %s: %s"),
2205 objfile_name (objfile
), e
.what ());
2208 /* The cie_table is discarded below. */
2215 dwarf2_get_section_info (objfile
, DWARF2_DEBUG_FRAME
,
2216 &unit
->dwarf_frame_section
,
2217 &unit
->dwarf_frame_buffer
,
2218 &unit
->dwarf_frame_size
);
2219 if (unit
->dwarf_frame_size
)
2221 size_t num_old_fde_entries
= fde_table
.size ();
2225 frame_ptr
= unit
->dwarf_frame_buffer
;
2226 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2227 frame_ptr
= decode_frame_entry (gdbarch
, unit
.get (), frame_ptr
, 0,
2228 cie_table
, &fde_table
,
2229 EH_CIE_OR_FDE_TYPE_ID
);
2231 catch (const gdb_exception_error
&e
)
2233 warning (_("skipping .debug_frame info of %s: %s"),
2234 objfile_name (objfile
), e
.what ());
2236 fde_table
.resize (num_old_fde_entries
);
2240 struct dwarf2_fde
*fde_prev
= NULL
;
2241 struct dwarf2_fde
*first_non_zero_fde
= NULL
;
2243 /* Prepare FDE table for lookups. */
2244 std::sort (fde_table
.begin (), fde_table
.end (), fde_is_less_than
);
2246 /* Check for leftovers from --gc-sections. The GNU linker sets
2247 the relevant symbols to zero, but doesn't zero the FDE *end*
2248 ranges because there's no relocation there. It's (offset,
2249 length), not (start, end). On targets where address zero is
2250 just another valid address this can be a problem, since the
2251 FDEs appear to be non-empty in the output --- we could pick
2252 out the wrong FDE. To work around this, when overlaps are
2253 detected, we prefer FDEs that do not start at zero.
2255 Start by finding the first FDE with non-zero start. Below
2256 we'll discard all FDEs that start at zero and overlap this
2258 for (struct dwarf2_fde
*fde
: fde_table
)
2260 if (fde
->initial_location
!= 0)
2262 first_non_zero_fde
= fde
;
2267 /* Since we'll be doing bsearch, squeeze out identical (except
2268 for eh_frame_p) fde entries so bsearch result is predictable.
2269 Also discard leftovers from --gc-sections. */
2270 for (struct dwarf2_fde
*fde
: fde_table
)
2272 if (fde
->initial_location
== 0
2273 && first_non_zero_fde
!= NULL
2274 && (first_non_zero_fde
->initial_location
2275 < fde
->initial_location
+ fde
->address_range
))
2278 if (fde_prev
!= NULL
2279 && fde_prev
->initial_location
== fde
->initial_location
)
2282 unit
->fde_table
.push_back (fde
);
2285 unit
->fde_table
.shrink_to_fit ();
2287 set_comp_unit (objfile
, unit
.release ());
2290 /* Handle 'maintenance show dwarf unwinders'. */
2293 show_dwarf_unwinders_enabled_p (struct ui_file
*file
, int from_tty
,
2294 struct cmd_list_element
*c
,
2297 fprintf_filtered (file
,
2298 _("The DWARF stack unwinders are currently %s.\n"),
2302 void _initialize_dwarf2_frame ();
2304 _initialize_dwarf2_frame ()
2306 dwarf2_frame_data
= gdbarch_data_register_pre_init (dwarf2_frame_init
);
2308 add_setshow_boolean_cmd ("unwinders", class_obscure
,
2309 &dwarf2_frame_unwinders_enabled_p
, _("\
2310 Set whether the DWARF stack frame unwinders are used."), _("\
2311 Show whether the DWARF stack frame unwinders are used."), _("\
2312 When enabled the DWARF stack frame unwinders can be used for architectures\n\
2313 that support the DWARF unwinders. Enabling the DWARF unwinders for an\n\
2314 architecture that doesn't support them will have no effect."),
2316 show_dwarf_unwinders_enabled_p
,
2318 &show_dwarf_cmdlist
);
2321 selftests::register_test_foreach_arch ("execute_cfa_program",
2322 selftests::execute_cfa_program_test
);