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 struct dwarf2_fde_table
135 struct dwarf2_fde
**entries
;
138 /* A minimal decoding of DWARF2 compilation units. We only decode
139 what's needed to get to the call frame information. */
143 /* Keep the bfd convenient. */
146 struct objfile
*objfile
;
148 /* Pointer to the .debug_frame section loaded into memory. */
149 const gdb_byte
*dwarf_frame_buffer
;
151 /* Length of the loaded .debug_frame section. */
152 bfd_size_type dwarf_frame_size
;
154 /* Pointer to the .debug_frame section. */
155 asection
*dwarf_frame_section
;
157 /* Base for DW_EH_PE_datarel encodings. */
160 /* Base for DW_EH_PE_textrel encodings. */
164 static struct dwarf2_fde
*dwarf2_frame_find_fde (CORE_ADDR
*pc
,
165 CORE_ADDR
*out_offset
);
167 static int dwarf2_frame_adjust_regnum (struct gdbarch
*gdbarch
, int regnum
,
170 static CORE_ADDR
read_encoded_value (struct comp_unit
*unit
, gdb_byte encoding
,
171 int ptr_len
, const gdb_byte
*buf
,
172 unsigned int *bytes_read_ptr
,
173 CORE_ADDR func_base
);
176 /* See dwarf2-frame.h. */
177 bool dwarf2_frame_unwinders_enabled_p
= true;
179 /* Store the length the expression for the CFA in the `cfa_reg' field,
180 which is unused in that case. */
181 #define cfa_exp_len cfa_reg
183 dwarf2_frame_state::dwarf2_frame_state (CORE_ADDR pc_
, struct dwarf2_cie
*cie
)
184 : pc (pc_
), data_align (cie
->data_alignment_factor
),
185 code_align (cie
->code_alignment_factor
),
186 retaddr_column (cie
->return_address_register
)
191 /* Helper functions for execute_stack_op. */
194 read_addr_from_reg (struct frame_info
*this_frame
, int reg
)
196 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
197 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, reg
);
199 return address_from_register (regnum
, this_frame
);
202 /* Execute the required actions for both the DW_CFA_restore and
203 DW_CFA_restore_extended instructions. */
205 dwarf2_restore_rule (struct gdbarch
*gdbarch
, ULONGEST reg_num
,
206 struct dwarf2_frame_state
*fs
, int eh_frame_p
)
210 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg_num
, eh_frame_p
);
211 fs
->regs
.alloc_regs (reg
+ 1);
213 /* Check if this register was explicitly initialized in the
214 CIE initial instructions. If not, default the rule to
216 if (reg
< fs
->initial
.reg
.size ())
217 fs
->regs
.reg
[reg
] = fs
->initial
.reg
[reg
];
219 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNSPECIFIED
;
221 if (fs
->regs
.reg
[reg
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
223 int regnum
= dwarf_reg_to_regnum (gdbarch
, reg
);
226 incomplete CFI data; DW_CFA_restore unspecified\n\
227 register %s (#%d) at %s"),
228 gdbarch_register_name (gdbarch
, regnum
), regnum
,
229 paddress (gdbarch
, fs
->pc
));
233 class dwarf_expr_executor
: public dwarf_expr_context
237 struct frame_info
*this_frame
;
239 CORE_ADDR
read_addr_from_reg (int reg
) override
241 return ::read_addr_from_reg (this_frame
, reg
);
244 struct value
*get_reg_value (struct type
*type
, int reg
) override
246 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
247 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, reg
);
249 return value_from_register (type
, regnum
, this_frame
);
252 void read_mem (gdb_byte
*buf
, CORE_ADDR addr
, size_t len
) override
254 read_memory (addr
, buf
, len
);
257 void get_frame_base (const gdb_byte
**start
, size_t *length
) override
259 invalid ("DW_OP_fbreg");
262 void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind
,
263 union call_site_parameter_u kind_u
,
264 int deref_size
) override
266 invalid ("DW_OP_entry_value");
269 CORE_ADDR
get_object_address () override
271 invalid ("DW_OP_push_object_address");
274 CORE_ADDR
get_frame_cfa () override
276 invalid ("DW_OP_call_frame_cfa");
279 CORE_ADDR
get_tls_address (CORE_ADDR offset
) override
281 invalid ("DW_OP_form_tls_address");
284 void dwarf_call (cu_offset die_offset
) override
286 invalid ("DW_OP_call*");
289 struct value
*dwarf_variable_value (sect_offset sect_off
) override
291 invalid ("DW_OP_GNU_variable_value");
294 CORE_ADDR
get_addr_index (unsigned int index
) override
296 invalid ("DW_OP_addrx or DW_OP_GNU_addr_index");
301 void invalid (const char *op
) ATTRIBUTE_NORETURN
303 error (_("%s is invalid in this context"), op
);
308 execute_stack_op (const gdb_byte
*exp
, ULONGEST len
, int addr_size
,
309 CORE_ADDR offset
, struct frame_info
*this_frame
,
310 CORE_ADDR initial
, int initial_in_stack_memory
)
314 dwarf_expr_executor ctx
;
315 scoped_value_mark free_values
;
317 ctx
.this_frame
= this_frame
;
318 ctx
.gdbarch
= get_frame_arch (this_frame
);
319 ctx
.addr_size
= addr_size
;
320 ctx
.ref_addr_size
= -1;
323 ctx
.push_address (initial
, initial_in_stack_memory
);
326 if (ctx
.location
== DWARF_VALUE_MEMORY
)
327 result
= ctx
.fetch_address (0);
328 else if (ctx
.location
== DWARF_VALUE_REGISTER
)
329 result
= ctx
.read_addr_from_reg (value_as_long (ctx
.fetch (0)));
332 /* This is actually invalid DWARF, but if we ever do run across
333 it somehow, we might as well support it. So, instead, report
334 it as unimplemented. */
336 Not implemented: computing unwound register using explicit value operator"));
343 /* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior
344 PC. Modify FS state accordingly. Return current INSN_PTR where the
345 execution has stopped, one can resume it on the next call. */
347 static const gdb_byte
*
348 execute_cfa_program (struct dwarf2_fde
*fde
, const gdb_byte
*insn_ptr
,
349 const gdb_byte
*insn_end
, struct gdbarch
*gdbarch
,
350 CORE_ADDR pc
, struct dwarf2_frame_state
*fs
)
352 int eh_frame_p
= fde
->eh_frame_p
;
353 unsigned int bytes_read
;
354 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
356 while (insn_ptr
< insn_end
&& fs
->pc
<= pc
)
358 gdb_byte insn
= *insn_ptr
++;
362 if ((insn
& 0xc0) == DW_CFA_advance_loc
)
363 fs
->pc
+= (insn
& 0x3f) * fs
->code_align
;
364 else if ((insn
& 0xc0) == DW_CFA_offset
)
367 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
368 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
369 offset
= utmp
* fs
->data_align
;
370 fs
->regs
.alloc_regs (reg
+ 1);
371 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
372 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
374 else if ((insn
& 0xc0) == DW_CFA_restore
)
377 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
384 fs
->pc
= read_encoded_value (fde
->cie
->unit
, fde
->cie
->encoding
,
385 fde
->cie
->ptr_size
, insn_ptr
,
386 &bytes_read
, fde
->initial_location
);
387 /* Apply the objfile offset for relocatable objects. */
388 fs
->pc
+= fde
->cie
->unit
->objfile
->text_section_offset ();
389 insn_ptr
+= bytes_read
;
392 case DW_CFA_advance_loc1
:
393 utmp
= extract_unsigned_integer (insn_ptr
, 1, byte_order
);
394 fs
->pc
+= utmp
* fs
->code_align
;
397 case DW_CFA_advance_loc2
:
398 utmp
= extract_unsigned_integer (insn_ptr
, 2, byte_order
);
399 fs
->pc
+= utmp
* fs
->code_align
;
402 case DW_CFA_advance_loc4
:
403 utmp
= extract_unsigned_integer (insn_ptr
, 4, byte_order
);
404 fs
->pc
+= utmp
* fs
->code_align
;
408 case DW_CFA_offset_extended
:
409 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
410 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
411 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
412 offset
= utmp
* fs
->data_align
;
413 fs
->regs
.alloc_regs (reg
+ 1);
414 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
415 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
418 case DW_CFA_restore_extended
:
419 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
420 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
423 case DW_CFA_undefined
:
424 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
425 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
426 fs
->regs
.alloc_regs (reg
+ 1);
427 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNDEFINED
;
430 case DW_CFA_same_value
:
431 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
432 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
433 fs
->regs
.alloc_regs (reg
+ 1);
434 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAME_VALUE
;
437 case DW_CFA_register
:
438 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
439 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
440 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
441 utmp
= dwarf2_frame_adjust_regnum (gdbarch
, utmp
, eh_frame_p
);
442 fs
->regs
.alloc_regs (reg
+ 1);
443 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_REG
;
444 fs
->regs
.reg
[reg
].loc
.reg
= utmp
;
447 case DW_CFA_remember_state
:
449 struct dwarf2_frame_state_reg_info
*new_rs
;
451 new_rs
= new dwarf2_frame_state_reg_info (fs
->regs
);
452 fs
->regs
.prev
= new_rs
;
456 case DW_CFA_restore_state
:
458 struct dwarf2_frame_state_reg_info
*old_rs
= fs
->regs
.prev
;
463 bad CFI data; mismatched DW_CFA_restore_state at %s"),
464 paddress (gdbarch
, fs
->pc
));
467 fs
->regs
= std::move (*old_rs
);
472 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
473 fs
->regs
.cfa_reg
= reg
;
474 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
476 if (fs
->armcc_cfa_offsets_sf
)
477 utmp
*= fs
->data_align
;
479 fs
->regs
.cfa_offset
= utmp
;
480 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
483 case DW_CFA_def_cfa_register
:
484 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
485 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
,
487 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
490 case DW_CFA_def_cfa_offset
:
491 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
493 if (fs
->armcc_cfa_offsets_sf
)
494 utmp
*= fs
->data_align
;
496 fs
->regs
.cfa_offset
= utmp
;
497 /* cfa_how deliberately not set. */
503 case DW_CFA_def_cfa_expression
:
504 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
505 fs
->regs
.cfa_exp_len
= utmp
;
506 fs
->regs
.cfa_exp
= insn_ptr
;
507 fs
->regs
.cfa_how
= CFA_EXP
;
508 insn_ptr
+= fs
->regs
.cfa_exp_len
;
511 case DW_CFA_expression
:
512 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
513 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
514 fs
->regs
.alloc_regs (reg
+ 1);
515 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
516 fs
->regs
.reg
[reg
].loc
.exp
.start
= insn_ptr
;
517 fs
->regs
.reg
[reg
].loc
.exp
.len
= utmp
;
518 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_EXP
;
522 case DW_CFA_offset_extended_sf
:
523 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
524 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
525 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
526 offset
*= fs
->data_align
;
527 fs
->regs
.alloc_regs (reg
+ 1);
528 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
529 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
532 case DW_CFA_val_offset
:
533 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
534 fs
->regs
.alloc_regs (reg
+ 1);
535 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
536 offset
= utmp
* fs
->data_align
;
537 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_OFFSET
;
538 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
541 case DW_CFA_val_offset_sf
:
542 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
543 fs
->regs
.alloc_regs (reg
+ 1);
544 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
545 offset
*= 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_expression
:
551 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
552 fs
->regs
.alloc_regs (reg
+ 1);
553 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
554 fs
->regs
.reg
[reg
].loc
.exp
.start
= insn_ptr
;
555 fs
->regs
.reg
[reg
].loc
.exp
.len
= utmp
;
556 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_EXP
;
560 case DW_CFA_def_cfa_sf
:
561 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
562 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
,
564 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
565 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
566 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
569 case DW_CFA_def_cfa_offset_sf
:
570 insn_ptr
= safe_read_sleb128 (insn_ptr
, insn_end
, &offset
);
571 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
572 /* cfa_how deliberately not set. */
575 case DW_CFA_GNU_args_size
:
577 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
580 case DW_CFA_GNU_negative_offset_extended
:
581 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, ®
);
582 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
583 insn_ptr
= safe_read_uleb128 (insn_ptr
, insn_end
, &utmp
);
584 offset
= utmp
* fs
->data_align
;
585 fs
->regs
.alloc_regs (reg
+ 1);
586 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
587 fs
->regs
.reg
[reg
].loc
.offset
= -offset
;
591 if (insn
>= DW_CFA_lo_user
&& insn
<= DW_CFA_hi_user
)
593 /* Handle vendor-specific CFI for different architectures. */
594 if (!gdbarch_execute_dwarf_cfa_vendor_op (gdbarch
, insn
, fs
))
595 error (_("Call Frame Instruction op %d in vendor extension "
596 "space is not handled on this architecture."),
600 internal_error (__FILE__
, __LINE__
,
601 _("Unknown CFI encountered."));
606 if (fs
->initial
.reg
.empty ())
608 /* Don't allow remember/restore between CIE and FDE programs. */
609 delete fs
->regs
.prev
;
610 fs
->regs
.prev
= NULL
;
618 namespace selftests
{
620 /* Unit test to function execute_cfa_program. */
623 execute_cfa_program_test (struct gdbarch
*gdbarch
)
625 struct dwarf2_fde fde
;
626 struct dwarf2_cie cie
;
628 memset (&fde
, 0, sizeof fde
);
629 memset (&cie
, 0, sizeof cie
);
631 cie
.data_alignment_factor
= -4;
632 cie
.code_alignment_factor
= 2;
635 dwarf2_frame_state
fs (0, fde
.cie
);
639 DW_CFA_def_cfa
, 1, 4, /* DW_CFA_def_cfa: r1 ofs 4 */
640 DW_CFA_offset
| 0x2, 1, /* DW_CFA_offset: r2 at cfa-4 */
641 DW_CFA_remember_state
,
642 DW_CFA_restore_state
,
645 const gdb_byte
*insn_end
= insns
+ sizeof (insns
);
646 const gdb_byte
*out
= execute_cfa_program (&fde
, insns
, insn_end
, gdbarch
,
649 SELF_CHECK (out
== insn_end
);
650 SELF_CHECK (fs
.pc
== 0);
652 /* The instructions above only use r1 and r2, but the register numbers
653 used are adjusted by dwarf2_frame_adjust_regnum. */
654 auto r1
= dwarf2_frame_adjust_regnum (gdbarch
, 1, fde
.eh_frame_p
);
655 auto r2
= dwarf2_frame_adjust_regnum (gdbarch
, 2, fde
.eh_frame_p
);
657 SELF_CHECK (fs
.regs
.reg
.size () == (std::max (r1
, r2
) + 1));
659 SELF_CHECK (fs
.regs
.reg
[r2
].how
== DWARF2_FRAME_REG_SAVED_OFFSET
);
660 SELF_CHECK (fs
.regs
.reg
[r2
].loc
.offset
== -4);
662 for (auto i
= 0; i
< fs
.regs
.reg
.size (); i
++)
664 SELF_CHECK (fs
.regs
.reg
[i
].how
== DWARF2_FRAME_REG_UNSPECIFIED
);
666 SELF_CHECK (fs
.regs
.cfa_reg
== 1);
667 SELF_CHECK (fs
.regs
.cfa_offset
== 4);
668 SELF_CHECK (fs
.regs
.cfa_how
== CFA_REG_OFFSET
);
669 SELF_CHECK (fs
.regs
.cfa_exp
== NULL
);
670 SELF_CHECK (fs
.regs
.prev
== NULL
);
673 } // namespace selftests
674 #endif /* GDB_SELF_TEST */
678 /* Architecture-specific operations. */
680 /* Per-architecture data key. */
681 static struct gdbarch_data
*dwarf2_frame_data
;
683 struct dwarf2_frame_ops
685 /* Pre-initialize the register state REG for register REGNUM. */
686 void (*init_reg
) (struct gdbarch
*, int, struct dwarf2_frame_state_reg
*,
687 struct frame_info
*);
689 /* Check whether the THIS_FRAME is a signal trampoline. */
690 int (*signal_frame_p
) (struct gdbarch
*, struct frame_info
*);
692 /* Convert .eh_frame register number to DWARF register number, or
693 adjust .debug_frame register number. */
694 int (*adjust_regnum
) (struct gdbarch
*, int, int);
697 /* Default architecture-specific register state initialization
701 dwarf2_frame_default_init_reg (struct gdbarch
*gdbarch
, int regnum
,
702 struct dwarf2_frame_state_reg
*reg
,
703 struct frame_info
*this_frame
)
705 /* If we have a register that acts as a program counter, mark it as
706 a destination for the return address. If we have a register that
707 serves as the stack pointer, arrange for it to be filled with the
708 call frame address (CFA). The other registers are marked as
711 We copy the return address to the program counter, since many
712 parts in GDB assume that it is possible to get the return address
713 by unwinding the program counter register. However, on ISA's
714 with a dedicated return address register, the CFI usually only
715 contains information to unwind that return address register.
717 The reason we're treating the stack pointer special here is
718 because in many cases GCC doesn't emit CFI for the stack pointer
719 and implicitly assumes that it is equal to the CFA. This makes
720 some sense since the DWARF specification (version 3, draft 8,
723 "Typically, the CFA is defined to be the value of the stack
724 pointer at the call site in the previous frame (which may be
725 different from its value on entry to the current frame)."
727 However, this isn't true for all platforms supported by GCC
728 (e.g. IBM S/390 and zSeries). Those architectures should provide
729 their own architecture-specific initialization function. */
731 if (regnum
== gdbarch_pc_regnum (gdbarch
))
732 reg
->how
= DWARF2_FRAME_REG_RA
;
733 else if (regnum
== gdbarch_sp_regnum (gdbarch
))
734 reg
->how
= DWARF2_FRAME_REG_CFA
;
737 /* Return a default for the architecture-specific operations. */
740 dwarf2_frame_init (struct obstack
*obstack
)
742 struct dwarf2_frame_ops
*ops
;
744 ops
= OBSTACK_ZALLOC (obstack
, struct dwarf2_frame_ops
);
745 ops
->init_reg
= dwarf2_frame_default_init_reg
;
749 /* Set the architecture-specific register state initialization
750 function for GDBARCH to INIT_REG. */
753 dwarf2_frame_set_init_reg (struct gdbarch
*gdbarch
,
754 void (*init_reg
) (struct gdbarch
*, int,
755 struct dwarf2_frame_state_reg
*,
756 struct frame_info
*))
758 struct dwarf2_frame_ops
*ops
759 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
761 ops
->init_reg
= init_reg
;
764 /* Pre-initialize the register state REG for register REGNUM. */
767 dwarf2_frame_init_reg (struct gdbarch
*gdbarch
, int regnum
,
768 struct dwarf2_frame_state_reg
*reg
,
769 struct frame_info
*this_frame
)
771 struct dwarf2_frame_ops
*ops
772 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
774 ops
->init_reg (gdbarch
, regnum
, reg
, this_frame
);
777 /* Set the architecture-specific signal trampoline recognition
778 function for GDBARCH to SIGNAL_FRAME_P. */
781 dwarf2_frame_set_signal_frame_p (struct gdbarch
*gdbarch
,
782 int (*signal_frame_p
) (struct gdbarch
*,
783 struct frame_info
*))
785 struct dwarf2_frame_ops
*ops
786 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
788 ops
->signal_frame_p
= signal_frame_p
;
791 /* Query the architecture-specific signal frame recognizer for
795 dwarf2_frame_signal_frame_p (struct gdbarch
*gdbarch
,
796 struct frame_info
*this_frame
)
798 struct dwarf2_frame_ops
*ops
799 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
801 if (ops
->signal_frame_p
== NULL
)
803 return ops
->signal_frame_p (gdbarch
, this_frame
);
806 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
810 dwarf2_frame_set_adjust_regnum (struct gdbarch
*gdbarch
,
811 int (*adjust_regnum
) (struct gdbarch
*,
814 struct dwarf2_frame_ops
*ops
815 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
817 ops
->adjust_regnum
= adjust_regnum
;
820 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
824 dwarf2_frame_adjust_regnum (struct gdbarch
*gdbarch
,
825 int regnum
, int eh_frame_p
)
827 struct dwarf2_frame_ops
*ops
828 = (struct dwarf2_frame_ops
*) gdbarch_data (gdbarch
, dwarf2_frame_data
);
830 if (ops
->adjust_regnum
== NULL
)
832 return ops
->adjust_regnum (gdbarch
, regnum
, eh_frame_p
);
836 dwarf2_frame_find_quirks (struct dwarf2_frame_state
*fs
,
837 struct dwarf2_fde
*fde
)
839 struct compunit_symtab
*cust
;
841 cust
= find_pc_compunit_symtab (fs
->pc
);
845 if (producer_is_realview (COMPUNIT_PRODUCER (cust
)))
847 if (fde
->cie
->version
== 1)
848 fs
->armcc_cfa_offsets_sf
= 1;
850 if (fde
->cie
->version
== 1)
851 fs
->armcc_cfa_offsets_reversed
= 1;
853 /* The reversed offset problem is present in some compilers
854 using DWARF3, but it was eventually fixed. Check the ARM
855 defined augmentations, which are in the format "armcc" followed
856 by a list of one-character options. The "+" option means
857 this problem is fixed (no quirk needed). If the armcc
858 augmentation is missing, the quirk is needed. */
859 if (fde
->cie
->version
== 3
860 && (!startswith (fde
->cie
->augmentation
, "armcc")
861 || strchr (fde
->cie
->augmentation
+ 5, '+') == NULL
))
862 fs
->armcc_cfa_offsets_reversed
= 1;
869 /* See dwarf2-frame.h. */
872 dwarf2_fetch_cfa_info (struct gdbarch
*gdbarch
, CORE_ADDR pc
,
873 struct dwarf2_per_cu_data
*data
,
874 int *regnum_out
, LONGEST
*offset_out
,
875 CORE_ADDR
*text_offset_out
,
876 const gdb_byte
**cfa_start_out
,
877 const gdb_byte
**cfa_end_out
)
879 struct dwarf2_fde
*fde
;
880 CORE_ADDR text_offset
;
883 /* Find the correct FDE. */
884 fde
= dwarf2_frame_find_fde (&pc1
, &text_offset
);
886 error (_("Could not compute CFA; needed to translate this expression"));
888 dwarf2_frame_state
fs (pc1
, fde
->cie
);
890 /* Check for "quirks" - known bugs in producers. */
891 dwarf2_frame_find_quirks (&fs
, fde
);
893 /* First decode all the insns in the CIE. */
894 execute_cfa_program (fde
, fde
->cie
->initial_instructions
,
895 fde
->cie
->end
, gdbarch
, pc
, &fs
);
897 /* Save the initialized register set. */
898 fs
.initial
= fs
.regs
;
900 /* Then decode the insns in the FDE up to our target PC. */
901 execute_cfa_program (fde
, fde
->instructions
, fde
->end
, gdbarch
, pc
, &fs
);
903 /* Calculate the CFA. */
904 switch (fs
.regs
.cfa_how
)
908 int regnum
= dwarf_reg_to_regnum_or_error (gdbarch
, fs
.regs
.cfa_reg
);
910 *regnum_out
= regnum
;
911 if (fs
.armcc_cfa_offsets_reversed
)
912 *offset_out
= -fs
.regs
.cfa_offset
;
914 *offset_out
= fs
.regs
.cfa_offset
;
919 *text_offset_out
= text_offset
;
920 *cfa_start_out
= fs
.regs
.cfa_exp
;
921 *cfa_end_out
= fs
.regs
.cfa_exp
+ fs
.regs
.cfa_exp_len
;
925 internal_error (__FILE__
, __LINE__
, _("Unknown CFA rule."));
930 struct dwarf2_frame_cache
932 /* DWARF Call Frame Address. */
935 /* Set if the return address column was marked as unavailable
936 (required non-collected memory or registers to compute). */
937 int unavailable_retaddr
;
939 /* Set if the return address column was marked as undefined. */
940 int undefined_retaddr
;
942 /* Saved registers, indexed by GDB register number, not by DWARF
944 struct dwarf2_frame_state_reg
*reg
;
946 /* Return address register. */
947 struct dwarf2_frame_state_reg retaddr_reg
;
949 /* Target address size in bytes. */
952 /* The .text offset. */
953 CORE_ADDR text_offset
;
955 /* True if we already checked whether this frame is the bottom frame
956 of a virtual tail call frame chain. */
957 int checked_tailcall_bottom
;
959 /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME
960 sequence. If NULL then it is a normal case with no TAILCALL_FRAME
961 involved. Non-bottom frames of a virtual tail call frames chain use
962 dwarf2_tailcall_frame_unwind unwinder so this field does not apply for
964 void *tailcall_cache
;
966 /* The number of bytes to subtract from TAILCALL_FRAME frames frame
967 base to get the SP, to simulate the return address pushed on the
969 LONGEST entry_cfa_sp_offset
;
970 int entry_cfa_sp_offset_p
;
973 static struct dwarf2_frame_cache
*
974 dwarf2_frame_cache (struct frame_info
*this_frame
, void **this_cache
)
976 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
977 const int num_regs
= gdbarch_num_cooked_regs (gdbarch
);
978 struct dwarf2_frame_cache
*cache
;
979 struct dwarf2_fde
*fde
;
981 const gdb_byte
*instr
;
984 return (struct dwarf2_frame_cache
*) *this_cache
;
986 /* Allocate a new cache. */
987 cache
= FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache
);
988 cache
->reg
= FRAME_OBSTACK_CALLOC (num_regs
, struct dwarf2_frame_state_reg
);
993 Note that if the next frame is never supposed to return (i.e. a call
994 to abort), the compiler might optimize away the instruction at
995 its return address. As a result the return address will
996 point at some random instruction, and the CFI for that
997 instruction is probably worthless to us. GCC's unwinder solves
998 this problem by substracting 1 from the return address to get an
999 address in the middle of a presumed call instruction (or the
1000 instruction in the associated delay slot). This should only be
1001 done for "normal" frames and not for resume-type frames (signal
1002 handlers, sentinel frames, dummy frames). The function
1003 get_frame_address_in_block does just this. It's not clear how
1004 reliable the method is though; there is the potential for the
1005 register state pre-call being different to that on return. */
1006 CORE_ADDR pc1
= get_frame_address_in_block (this_frame
);
1008 /* Find the correct FDE. */
1009 fde
= dwarf2_frame_find_fde (&pc1
, &cache
->text_offset
);
1010 gdb_assert (fde
!= NULL
);
1012 /* Allocate and initialize the frame state. */
1013 struct dwarf2_frame_state
fs (pc1
, fde
->cie
);
1015 cache
->addr_size
= fde
->cie
->addr_size
;
1017 /* Check for "quirks" - known bugs in producers. */
1018 dwarf2_frame_find_quirks (&fs
, fde
);
1020 /* First decode all the insns in the CIE. */
1021 execute_cfa_program (fde
, fde
->cie
->initial_instructions
,
1022 fde
->cie
->end
, gdbarch
,
1023 get_frame_address_in_block (this_frame
), &fs
);
1025 /* Save the initialized register set. */
1026 fs
.initial
= fs
.regs
;
1028 /* Fetching the entry pc for THIS_FRAME won't necessarily result
1029 in an address that's within the range of FDE locations. This
1030 is due to the possibility of the function occupying non-contiguous
1032 if (get_frame_func_if_available (this_frame
, &entry_pc
)
1033 && fde
->initial_location
<= entry_pc
1034 && entry_pc
< fde
->initial_location
+ fde
->address_range
)
1036 /* Decode the insns in the FDE up to the entry PC. */
1037 instr
= execute_cfa_program (fde
, fde
->instructions
, fde
->end
, gdbarch
,
1040 if (fs
.regs
.cfa_how
== CFA_REG_OFFSET
1041 && (dwarf_reg_to_regnum (gdbarch
, fs
.regs
.cfa_reg
)
1042 == gdbarch_sp_regnum (gdbarch
)))
1044 cache
->entry_cfa_sp_offset
= fs
.regs
.cfa_offset
;
1045 cache
->entry_cfa_sp_offset_p
= 1;
1049 instr
= fde
->instructions
;
1051 /* Then decode the insns in the FDE up to our target PC. */
1052 execute_cfa_program (fde
, instr
, fde
->end
, gdbarch
,
1053 get_frame_address_in_block (this_frame
), &fs
);
1057 /* Calculate the CFA. */
1058 switch (fs
.regs
.cfa_how
)
1060 case CFA_REG_OFFSET
:
1061 cache
->cfa
= read_addr_from_reg (this_frame
, fs
.regs
.cfa_reg
);
1062 if (fs
.armcc_cfa_offsets_reversed
)
1063 cache
->cfa
-= fs
.regs
.cfa_offset
;
1065 cache
->cfa
+= fs
.regs
.cfa_offset
;
1070 execute_stack_op (fs
.regs
.cfa_exp
, fs
.regs
.cfa_exp_len
,
1071 cache
->addr_size
, cache
->text_offset
,
1076 internal_error (__FILE__
, __LINE__
, _("Unknown CFA rule."));
1079 catch (const gdb_exception_error
&ex
)
1081 if (ex
.error
== NOT_AVAILABLE_ERROR
)
1083 cache
->unavailable_retaddr
= 1;
1090 /* Initialize the register state. */
1094 for (regnum
= 0; regnum
< num_regs
; regnum
++)
1095 dwarf2_frame_init_reg (gdbarch
, regnum
, &cache
->reg
[regnum
], this_frame
);
1098 /* Go through the DWARF2 CFI generated table and save its register
1099 location information in the cache. Note that we don't skip the
1100 return address column; it's perfectly all right for it to
1101 correspond to a real register. */
1103 int column
; /* CFI speak for "register number". */
1105 for (column
= 0; column
< fs
.regs
.reg
.size (); column
++)
1107 /* Use the GDB register number as the destination index. */
1108 int regnum
= dwarf_reg_to_regnum (gdbarch
, column
);
1110 /* Protect against a target returning a bad register. */
1111 if (regnum
< 0 || regnum
>= num_regs
)
1114 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1115 of all debug info registers. If it doesn't, complain (but
1116 not too loudly). It turns out that GCC assumes that an
1117 unspecified register implies "same value" when CFI (draft
1118 7) specifies nothing at all. Such a register could equally
1119 be interpreted as "undefined". Also note that this check
1120 isn't sufficient; it only checks that all registers in the
1121 range [0 .. max column] are specified, and won't detect
1122 problems when a debug info register falls outside of the
1123 table. We need a way of iterating through all the valid
1124 DWARF2 register numbers. */
1125 if (fs
.regs
.reg
[column
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
1127 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
1129 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1130 gdbarch_register_name (gdbarch
, regnum
),
1131 paddress (gdbarch
, fs
.pc
));
1134 cache
->reg
[regnum
] = fs
.regs
.reg
[column
];
1138 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1139 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1143 for (regnum
= 0; regnum
< num_regs
; regnum
++)
1145 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
1146 || cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA_OFFSET
)
1148 const std::vector
<struct dwarf2_frame_state_reg
> ®s
1150 ULONGEST retaddr_column
= fs
.retaddr_column
;
1152 /* It seems rather bizarre to specify an "empty" column as
1153 the return adress column. However, this is exactly
1154 what GCC does on some targets. It turns out that GCC
1155 assumes that the return address can be found in the
1156 register corresponding to the return address column.
1157 Incidentally, that's how we should treat a return
1158 address column specifying "same value" too. */
1159 if (fs
.retaddr_column
< fs
.regs
.reg
.size ()
1160 && regs
[retaddr_column
].how
!= DWARF2_FRAME_REG_UNSPECIFIED
1161 && regs
[retaddr_column
].how
!= DWARF2_FRAME_REG_SAME_VALUE
)
1163 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1164 cache
->reg
[regnum
] = regs
[retaddr_column
];
1166 cache
->retaddr_reg
= regs
[retaddr_column
];
1170 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1172 cache
->reg
[regnum
].loc
.reg
= fs
.retaddr_column
;
1173 cache
->reg
[regnum
].how
= DWARF2_FRAME_REG_SAVED_REG
;
1177 cache
->retaddr_reg
.loc
.reg
= fs
.retaddr_column
;
1178 cache
->retaddr_reg
.how
= DWARF2_FRAME_REG_SAVED_REG
;
1185 if (fs
.retaddr_column
< fs
.regs
.reg
.size ()
1186 && fs
.regs
.reg
[fs
.retaddr_column
].how
== DWARF2_FRAME_REG_UNDEFINED
)
1187 cache
->undefined_retaddr
= 1;
1192 static enum unwind_stop_reason
1193 dwarf2_frame_unwind_stop_reason (struct frame_info
*this_frame
,
1196 struct dwarf2_frame_cache
*cache
1197 = dwarf2_frame_cache (this_frame
, this_cache
);
1199 if (cache
->unavailable_retaddr
)
1200 return UNWIND_UNAVAILABLE
;
1202 if (cache
->undefined_retaddr
)
1203 return UNWIND_OUTERMOST
;
1205 return UNWIND_NO_REASON
;
1209 dwarf2_frame_this_id (struct frame_info
*this_frame
, void **this_cache
,
1210 struct frame_id
*this_id
)
1212 struct dwarf2_frame_cache
*cache
=
1213 dwarf2_frame_cache (this_frame
, this_cache
);
1215 if (cache
->unavailable_retaddr
)
1216 (*this_id
) = frame_id_build_unavailable_stack (get_frame_func (this_frame
));
1217 else if (cache
->undefined_retaddr
)
1220 (*this_id
) = frame_id_build (cache
->cfa
, get_frame_func (this_frame
));
1223 static struct value
*
1224 dwarf2_frame_prev_register (struct frame_info
*this_frame
, void **this_cache
,
1227 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
1228 struct dwarf2_frame_cache
*cache
=
1229 dwarf2_frame_cache (this_frame
, this_cache
);
1233 /* Check whether THIS_FRAME is the bottom frame of a virtual tail
1234 call frame chain. */
1235 if (!cache
->checked_tailcall_bottom
)
1237 cache
->checked_tailcall_bottom
= 1;
1238 dwarf2_tailcall_sniffer_first (this_frame
, &cache
->tailcall_cache
,
1239 (cache
->entry_cfa_sp_offset_p
1240 ? &cache
->entry_cfa_sp_offset
: NULL
));
1243 /* Non-bottom frames of a virtual tail call frames chain use
1244 dwarf2_tailcall_frame_unwind unwinder so this code does not apply for
1245 them. If dwarf2_tailcall_prev_register_first does not have specific value
1246 unwind the register, tail call frames are assumed to have the register set
1247 of the top caller. */
1248 if (cache
->tailcall_cache
)
1252 val
= dwarf2_tailcall_prev_register_first (this_frame
,
1253 &cache
->tailcall_cache
,
1259 switch (cache
->reg
[regnum
].how
)
1261 case DWARF2_FRAME_REG_UNDEFINED
:
1262 /* If CFI explicitly specified that the value isn't defined,
1263 mark it as optimized away; the value isn't available. */
1264 return frame_unwind_got_optimized (this_frame
, regnum
);
1266 case DWARF2_FRAME_REG_SAVED_OFFSET
:
1267 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1268 return frame_unwind_got_memory (this_frame
, regnum
, addr
);
1270 case DWARF2_FRAME_REG_SAVED_REG
:
1271 realnum
= dwarf_reg_to_regnum_or_error
1272 (gdbarch
, cache
->reg
[regnum
].loc
.reg
);
1273 return frame_unwind_got_register (this_frame
, regnum
, realnum
);
1275 case DWARF2_FRAME_REG_SAVED_EXP
:
1276 addr
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
.start
,
1277 cache
->reg
[regnum
].loc
.exp
.len
,
1278 cache
->addr_size
, cache
->text_offset
,
1279 this_frame
, cache
->cfa
, 1);
1280 return frame_unwind_got_memory (this_frame
, regnum
, addr
);
1282 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET
:
1283 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1284 return frame_unwind_got_constant (this_frame
, regnum
, addr
);
1286 case DWARF2_FRAME_REG_SAVED_VAL_EXP
:
1287 addr
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
.start
,
1288 cache
->reg
[regnum
].loc
.exp
.len
,
1289 cache
->addr_size
, cache
->text_offset
,
1290 this_frame
, cache
->cfa
, 1);
1291 return frame_unwind_got_constant (this_frame
, regnum
, addr
);
1293 case DWARF2_FRAME_REG_UNSPECIFIED
:
1294 /* GCC, in its infinite wisdom decided to not provide unwind
1295 information for registers that are "same value". Since
1296 DWARF2 (3 draft 7) doesn't define such behavior, said
1297 registers are actually undefined (which is different to CFI
1298 "undefined"). Code above issues a complaint about this.
1299 Here just fudge the books, assume GCC, and that the value is
1300 more inner on the stack. */
1301 return frame_unwind_got_register (this_frame
, regnum
, regnum
);
1303 case DWARF2_FRAME_REG_SAME_VALUE
:
1304 return frame_unwind_got_register (this_frame
, regnum
, regnum
);
1306 case DWARF2_FRAME_REG_CFA
:
1307 return frame_unwind_got_address (this_frame
, regnum
, cache
->cfa
);
1309 case DWARF2_FRAME_REG_CFA_OFFSET
:
1310 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1311 return frame_unwind_got_address (this_frame
, regnum
, addr
);
1313 case DWARF2_FRAME_REG_RA_OFFSET
:
1314 addr
= cache
->reg
[regnum
].loc
.offset
;
1315 regnum
= dwarf_reg_to_regnum_or_error
1316 (gdbarch
, cache
->retaddr_reg
.loc
.reg
);
1317 addr
+= get_frame_register_unsigned (this_frame
, regnum
);
1318 return frame_unwind_got_address (this_frame
, regnum
, addr
);
1320 case DWARF2_FRAME_REG_FN
:
1321 return cache
->reg
[regnum
].loc
.fn (this_frame
, this_cache
, regnum
);
1324 internal_error (__FILE__
, __LINE__
, _("Unknown register rule."));
1328 /* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail
1329 call frames chain. */
1332 dwarf2_frame_dealloc_cache (struct frame_info
*self
, void *this_cache
)
1334 struct dwarf2_frame_cache
*cache
= dwarf2_frame_cache (self
, &this_cache
);
1336 if (cache
->tailcall_cache
)
1337 dwarf2_tailcall_frame_unwind
.dealloc_cache (self
, cache
->tailcall_cache
);
1341 dwarf2_frame_sniffer (const struct frame_unwind
*self
,
1342 struct frame_info
*this_frame
, void **this_cache
)
1344 if (!dwarf2_frame_unwinders_enabled_p
)
1347 /* Grab an address that is guaranteed to reside somewhere within the
1348 function. get_frame_pc(), with a no-return next function, can
1349 end up returning something past the end of this function's body.
1350 If the frame we're sniffing for is a signal frame whose start
1351 address is placed on the stack by the OS, its FDE must
1352 extend one byte before its start address or we could potentially
1353 select the FDE of the previous function. */
1354 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1355 struct dwarf2_fde
*fde
= dwarf2_frame_find_fde (&block_addr
, NULL
);
1360 /* On some targets, signal trampolines may have unwind information.
1361 We need to recognize them so that we set the frame type
1364 if (fde
->cie
->signal_frame
1365 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame
),
1367 return self
->type
== SIGTRAMP_FRAME
;
1369 if (self
->type
!= NORMAL_FRAME
)
1375 static const struct frame_unwind dwarf2_frame_unwind
=
1378 dwarf2_frame_unwind_stop_reason
,
1379 dwarf2_frame_this_id
,
1380 dwarf2_frame_prev_register
,
1382 dwarf2_frame_sniffer
,
1383 dwarf2_frame_dealloc_cache
1386 static const struct frame_unwind dwarf2_signal_frame_unwind
=
1389 dwarf2_frame_unwind_stop_reason
,
1390 dwarf2_frame_this_id
,
1391 dwarf2_frame_prev_register
,
1393 dwarf2_frame_sniffer
,
1395 /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */
1399 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1402 dwarf2_append_unwinders (struct gdbarch
*gdbarch
)
1404 /* TAILCALL_FRAME must be first to find the record by
1405 dwarf2_tailcall_sniffer_first. */
1406 frame_unwind_append_unwinder (gdbarch
, &dwarf2_tailcall_frame_unwind
);
1408 frame_unwind_append_unwinder (gdbarch
, &dwarf2_frame_unwind
);
1409 frame_unwind_append_unwinder (gdbarch
, &dwarf2_signal_frame_unwind
);
1413 /* There is no explicitly defined relationship between the CFA and the
1414 location of frame's local variables and arguments/parameters.
1415 Therefore, frame base methods on this page should probably only be
1416 used as a last resort, just to avoid printing total garbage as a
1417 response to the "info frame" command. */
1420 dwarf2_frame_base_address (struct frame_info
*this_frame
, void **this_cache
)
1422 struct dwarf2_frame_cache
*cache
=
1423 dwarf2_frame_cache (this_frame
, this_cache
);
1428 static const struct frame_base dwarf2_frame_base
=
1430 &dwarf2_frame_unwind
,
1431 dwarf2_frame_base_address
,
1432 dwarf2_frame_base_address
,
1433 dwarf2_frame_base_address
1436 const struct frame_base
*
1437 dwarf2_frame_base_sniffer (struct frame_info
*this_frame
)
1439 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1441 if (dwarf2_frame_find_fde (&block_addr
, NULL
))
1442 return &dwarf2_frame_base
;
1447 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1448 the DWARF unwinder. This is used to implement
1449 DW_OP_call_frame_cfa. */
1452 dwarf2_frame_cfa (struct frame_info
*this_frame
)
1454 if (frame_unwinder_is (this_frame
, &record_btrace_tailcall_frame_unwind
)
1455 || frame_unwinder_is (this_frame
, &record_btrace_frame_unwind
))
1456 throw_error (NOT_AVAILABLE_ERROR
,
1457 _("cfa not available for record btrace target"));
1459 while (get_frame_type (this_frame
) == INLINE_FRAME
)
1460 this_frame
= get_prev_frame (this_frame
);
1461 if (get_frame_unwind_stop_reason (this_frame
) == UNWIND_UNAVAILABLE
)
1462 throw_error (NOT_AVAILABLE_ERROR
,
1463 _("can't compute CFA for this frame: "
1464 "required registers or memory are unavailable"));
1466 if (get_frame_id (this_frame
).stack_status
!= FID_STACK_VALID
)
1467 throw_error (NOT_AVAILABLE_ERROR
,
1468 _("can't compute CFA for this frame: "
1469 "frame base not available"));
1471 return get_frame_base (this_frame
);
1474 const struct objfile_key
<dwarf2_fde_table
,
1475 gdb::noop_deleter
<dwarf2_fde_table
>>
1476 dwarf2_frame_objfile_data
;
1480 /* Pointer encoding helper functions. */
1482 /* GCC supports exception handling based on DWARF2 CFI. However, for
1483 technical reasons, it encodes addresses in its FDE's in a different
1484 way. Several "pointer encodings" are supported. The encoding
1485 that's used for a particular FDE is determined by the 'R'
1486 augmentation in the associated CIE. The argument of this
1487 augmentation is a single byte.
1489 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1490 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1491 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1492 address should be interpreted (absolute, relative to the current
1493 position in the FDE, ...). Bit 7, indicates that the address
1494 should be dereferenced. */
1497 encoding_for_size (unsigned int size
)
1502 return DW_EH_PE_udata2
;
1504 return DW_EH_PE_udata4
;
1506 return DW_EH_PE_udata8
;
1508 internal_error (__FILE__
, __LINE__
, _("Unsupported address size"));
1513 read_encoded_value (struct comp_unit
*unit
, gdb_byte encoding
,
1514 int ptr_len
, const gdb_byte
*buf
,
1515 unsigned int *bytes_read_ptr
,
1516 CORE_ADDR func_base
)
1521 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1523 if (encoding
& DW_EH_PE_indirect
)
1524 internal_error (__FILE__
, __LINE__
,
1525 _("Unsupported encoding: DW_EH_PE_indirect"));
1527 *bytes_read_ptr
= 0;
1529 switch (encoding
& 0x70)
1531 case DW_EH_PE_absptr
:
1534 case DW_EH_PE_pcrel
:
1535 base
= bfd_section_vma (unit
->dwarf_frame_section
);
1536 base
+= (buf
- unit
->dwarf_frame_buffer
);
1538 case DW_EH_PE_datarel
:
1541 case DW_EH_PE_textrel
:
1544 case DW_EH_PE_funcrel
:
1547 case DW_EH_PE_aligned
:
1549 offset
= buf
- unit
->dwarf_frame_buffer
;
1550 if ((offset
% ptr_len
) != 0)
1552 *bytes_read_ptr
= ptr_len
- (offset
% ptr_len
);
1553 buf
+= *bytes_read_ptr
;
1557 internal_error (__FILE__
, __LINE__
,
1558 _("Invalid or unsupported encoding"));
1561 if ((encoding
& 0x07) == 0x00)
1563 encoding
|= encoding_for_size (ptr_len
);
1564 if (bfd_get_sign_extend_vma (unit
->abfd
))
1565 encoding
|= DW_EH_PE_signed
;
1568 switch (encoding
& 0x0f)
1570 case DW_EH_PE_uleb128
:
1573 const gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1575 *bytes_read_ptr
+= safe_read_uleb128 (buf
, end_buf
, &value
) - buf
;
1576 return base
+ value
;
1578 case DW_EH_PE_udata2
:
1579 *bytes_read_ptr
+= 2;
1580 return (base
+ bfd_get_16 (unit
->abfd
, (bfd_byte
*) buf
));
1581 case DW_EH_PE_udata4
:
1582 *bytes_read_ptr
+= 4;
1583 return (base
+ bfd_get_32 (unit
->abfd
, (bfd_byte
*) buf
));
1584 case DW_EH_PE_udata8
:
1585 *bytes_read_ptr
+= 8;
1586 return (base
+ bfd_get_64 (unit
->abfd
, (bfd_byte
*) buf
));
1587 case DW_EH_PE_sleb128
:
1590 const gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1592 *bytes_read_ptr
+= safe_read_sleb128 (buf
, end_buf
, &value
) - buf
;
1593 return base
+ value
;
1595 case DW_EH_PE_sdata2
:
1596 *bytes_read_ptr
+= 2;
1597 return (base
+ bfd_get_signed_16 (unit
->abfd
, (bfd_byte
*) buf
));
1598 case DW_EH_PE_sdata4
:
1599 *bytes_read_ptr
+= 4;
1600 return (base
+ bfd_get_signed_32 (unit
->abfd
, (bfd_byte
*) buf
));
1601 case DW_EH_PE_sdata8
:
1602 *bytes_read_ptr
+= 8;
1603 return (base
+ bfd_get_signed_64 (unit
->abfd
, (bfd_byte
*) buf
));
1605 internal_error (__FILE__
, __LINE__
,
1606 _("Invalid or unsupported encoding"));
1611 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1612 static struct dwarf2_cie
*
1613 find_cie (const dwarf2_cie_table
&cie_table
, ULONGEST cie_pointer
)
1615 auto iter
= cie_table
.find (cie_pointer
);
1616 if (iter
!= cie_table
.end ())
1617 return iter
->second
;
1622 bsearch_fde_cmp (const dwarf2_fde
*fde
, CORE_ADDR seek_pc
)
1624 if (fde
->initial_location
+ fde
->address_range
<= seek_pc
)
1626 if (fde
->initial_location
<= seek_pc
)
1631 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1632 initial location associated with it into *PC. */
1634 static struct dwarf2_fde
*
1635 dwarf2_frame_find_fde (CORE_ADDR
*pc
, CORE_ADDR
*out_offset
)
1637 for (objfile
*objfile
: current_program_space
->objfiles ())
1639 struct dwarf2_fde_table
*fde_table
;
1643 fde_table
= dwarf2_frame_objfile_data
.get (objfile
);
1644 if (fde_table
== NULL
)
1646 dwarf2_build_frame_info (objfile
);
1647 fde_table
= dwarf2_frame_objfile_data
.get (objfile
);
1649 gdb_assert (fde_table
!= NULL
);
1651 if (fde_table
->num_entries
== 0)
1654 gdb_assert (!objfile
->section_offsets
.empty ());
1655 offset
= objfile
->text_section_offset ();
1657 gdb_assert (fde_table
->num_entries
> 0);
1658 if (*pc
< offset
+ fde_table
->entries
[0]->initial_location
)
1661 seek_pc
= *pc
- offset
;
1662 auto end
= fde_table
->entries
+ fde_table
->num_entries
;
1663 auto it
= gdb::binary_search (fde_table
->entries
, end
, seek_pc
, bsearch_fde_cmp
);
1666 *pc
= (*it
)->initial_location
+ offset
;
1668 *out_offset
= offset
;
1675 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1677 add_fde (struct dwarf2_fde_table
*fde_table
, struct dwarf2_fde
*fde
)
1679 if (fde
->address_range
== 0)
1680 /* Discard useless FDEs. */
1683 fde_table
->num_entries
+= 1;
1684 fde_table
->entries
= XRESIZEVEC (struct dwarf2_fde
*, fde_table
->entries
,
1685 fde_table
->num_entries
);
1686 fde_table
->entries
[fde_table
->num_entries
- 1] = fde
;
1689 #define DW64_CIE_ID 0xffffffffffffffffULL
1691 /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
1696 EH_CIE_TYPE_ID
= 1 << 0,
1697 EH_FDE_TYPE_ID
= 1 << 1,
1698 EH_CIE_OR_FDE_TYPE_ID
= EH_CIE_TYPE_ID
| EH_FDE_TYPE_ID
1701 static const gdb_byte
*decode_frame_entry (struct comp_unit
*unit
,
1702 const gdb_byte
*start
,
1704 dwarf2_cie_table
&cie_table
,
1705 struct dwarf2_fde_table
*fde_table
,
1706 enum eh_frame_type entry_type
);
1708 /* Decode the next CIE or FDE, entry_type specifies the expected type.
1709 Return NULL if invalid input, otherwise the next byte to be processed. */
1711 static const gdb_byte
*
1712 decode_frame_entry_1 (struct comp_unit
*unit
, const gdb_byte
*start
,
1714 dwarf2_cie_table
&cie_table
,
1715 struct dwarf2_fde_table
*fde_table
,
1716 enum eh_frame_type entry_type
)
1718 struct gdbarch
*gdbarch
= get_objfile_arch (unit
->objfile
);
1719 const gdb_byte
*buf
, *end
;
1721 unsigned int bytes_read
;
1724 ULONGEST cie_pointer
;
1729 length
= read_initial_length (unit
->abfd
, buf
, &bytes_read
, false);
1731 end
= buf
+ (size_t) length
;
1736 /* Are we still within the section? */
1737 if (end
<= buf
|| end
> unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
1740 /* Distinguish between 32 and 64-bit encoded frame info. */
1741 dwarf64_p
= (bytes_read
== 12);
1743 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1747 cie_id
= DW64_CIE_ID
;
1753 cie_pointer
= read_8_bytes (unit
->abfd
, buf
);
1758 cie_pointer
= read_4_bytes (unit
->abfd
, buf
);
1762 if (cie_pointer
== cie_id
)
1764 /* This is a CIE. */
1765 struct dwarf2_cie
*cie
;
1767 unsigned int cie_version
;
1769 /* Check that a CIE was expected. */
1770 if ((entry_type
& EH_CIE_TYPE_ID
) == 0)
1771 error (_("Found a CIE when not expecting it."));
1773 /* Record the offset into the .debug_frame section of this CIE. */
1774 cie_pointer
= start
- unit
->dwarf_frame_buffer
;
1776 /* Check whether we've already read it. */
1777 if (find_cie (cie_table
, cie_pointer
))
1780 cie
= XOBNEW (&unit
->objfile
->objfile_obstack
, struct dwarf2_cie
);
1781 cie
->initial_instructions
= NULL
;
1782 cie
->cie_pointer
= cie_pointer
;
1784 /* The encoding for FDE's in a normal .debug_frame section
1785 depends on the target address size. */
1786 cie
->encoding
= DW_EH_PE_absptr
;
1788 /* We'll determine the final value later, but we need to
1789 initialize it conservatively. */
1790 cie
->signal_frame
= 0;
1792 /* Check version number. */
1793 cie_version
= read_1_byte (unit
->abfd
, buf
);
1794 if (cie_version
!= 1 && cie_version
!= 3 && cie_version
!= 4)
1796 cie
->version
= cie_version
;
1799 /* Interpret the interesting bits of the augmentation. */
1800 cie
->augmentation
= augmentation
= (char *) buf
;
1801 buf
+= (strlen (augmentation
) + 1);
1803 /* Ignore armcc augmentations. We only use them for quirks,
1804 and that doesn't happen until later. */
1805 if (startswith (augmentation
, "armcc"))
1806 augmentation
+= strlen (augmentation
);
1808 /* The GCC 2.x "eh" augmentation has a pointer immediately
1809 following the augmentation string, so it must be handled
1811 if (augmentation
[0] == 'e' && augmentation
[1] == 'h')
1814 buf
+= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1818 if (cie
->version
>= 4)
1820 /* FIXME: check that this is the same as from the CU header. */
1821 cie
->addr_size
= read_1_byte (unit
->abfd
, buf
);
1823 cie
->segment_size
= read_1_byte (unit
->abfd
, buf
);
1828 cie
->addr_size
= gdbarch_dwarf2_addr_size (gdbarch
);
1829 cie
->segment_size
= 0;
1831 /* Address values in .eh_frame sections are defined to have the
1832 target's pointer size. Watchout: This breaks frame info for
1833 targets with pointer size < address size, unless a .debug_frame
1834 section exists as well. */
1836 cie
->ptr_size
= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1838 cie
->ptr_size
= cie
->addr_size
;
1840 buf
= gdb_read_uleb128 (buf
, end
, &uleb128
);
1843 cie
->code_alignment_factor
= uleb128
;
1845 buf
= gdb_read_sleb128 (buf
, end
, &sleb128
);
1848 cie
->data_alignment_factor
= sleb128
;
1850 if (cie_version
== 1)
1852 cie
->return_address_register
= read_1_byte (unit
->abfd
, buf
);
1857 buf
= gdb_read_uleb128 (buf
, end
, &uleb128
);
1860 cie
->return_address_register
= uleb128
;
1863 cie
->return_address_register
1864 = dwarf2_frame_adjust_regnum (gdbarch
,
1865 cie
->return_address_register
,
1868 cie
->saw_z_augmentation
= (*augmentation
== 'z');
1869 if (cie
->saw_z_augmentation
)
1871 uint64_t uleb_length
;
1873 buf
= gdb_read_uleb128 (buf
, end
, &uleb_length
);
1876 cie
->initial_instructions
= buf
+ uleb_length
;
1880 while (*augmentation
)
1882 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1883 if (*augmentation
== 'L')
1890 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1891 else if (*augmentation
== 'R')
1893 cie
->encoding
= *buf
++;
1897 /* "P" indicates a personality routine in the CIE augmentation. */
1898 else if (*augmentation
== 'P')
1900 /* Skip. Avoid indirection since we throw away the result. */
1901 gdb_byte encoding
= (*buf
++) & ~DW_EH_PE_indirect
;
1902 read_encoded_value (unit
, encoding
, cie
->ptr_size
,
1903 buf
, &bytes_read
, 0);
1908 /* "S" indicates a signal frame, such that the return
1909 address must not be decremented to locate the call frame
1910 info for the previous frame; it might even be the first
1911 instruction of a function, so decrementing it would take
1912 us to a different function. */
1913 else if (*augmentation
== 'S')
1915 cie
->signal_frame
= 1;
1919 /* Otherwise we have an unknown augmentation. Assume that either
1920 there is no augmentation data, or we saw a 'z' prefix. */
1923 if (cie
->initial_instructions
)
1924 buf
= cie
->initial_instructions
;
1929 cie
->initial_instructions
= buf
;
1933 cie_table
[cie
->cie_pointer
] = cie
;
1937 /* This is a FDE. */
1938 struct dwarf2_fde
*fde
;
1941 /* Check that an FDE was expected. */
1942 if ((entry_type
& EH_FDE_TYPE_ID
) == 0)
1943 error (_("Found an FDE when not expecting it."));
1945 /* In an .eh_frame section, the CIE pointer is the delta between the
1946 address within the FDE where the CIE pointer is stored and the
1947 address of the CIE. Convert it to an offset into the .eh_frame
1951 cie_pointer
= buf
- unit
->dwarf_frame_buffer
- cie_pointer
;
1952 cie_pointer
-= (dwarf64_p
? 8 : 4);
1955 /* In either case, validate the result is still within the section. */
1956 if (cie_pointer
>= unit
->dwarf_frame_size
)
1959 fde
= XOBNEW (&unit
->objfile
->objfile_obstack
, struct dwarf2_fde
);
1960 fde
->cie
= find_cie (cie_table
, cie_pointer
);
1961 if (fde
->cie
== NULL
)
1963 decode_frame_entry (unit
, unit
->dwarf_frame_buffer
+ cie_pointer
,
1964 eh_frame_p
, cie_table
, fde_table
,
1966 fde
->cie
= find_cie (cie_table
, cie_pointer
);
1969 gdb_assert (fde
->cie
!= NULL
);
1971 addr
= read_encoded_value (unit
, fde
->cie
->encoding
, fde
->cie
->ptr_size
,
1972 buf
, &bytes_read
, 0);
1973 fde
->initial_location
= gdbarch_adjust_dwarf2_addr (gdbarch
, addr
);
1976 fde
->address_range
=
1977 read_encoded_value (unit
, fde
->cie
->encoding
& 0x0f,
1978 fde
->cie
->ptr_size
, buf
, &bytes_read
, 0);
1979 addr
= gdbarch_adjust_dwarf2_addr (gdbarch
, addr
+ fde
->address_range
);
1980 fde
->address_range
= addr
- fde
->initial_location
;
1983 /* A 'z' augmentation in the CIE implies the presence of an
1984 augmentation field in the FDE as well. The only thing known
1985 to be in here at present is the LSDA entry for EH. So we
1986 can skip the whole thing. */
1987 if (fde
->cie
->saw_z_augmentation
)
1989 uint64_t uleb_length
;
1991 buf
= gdb_read_uleb128 (buf
, end
, &uleb_length
);
1999 fde
->instructions
= buf
;
2002 fde
->eh_frame_p
= eh_frame_p
;
2004 add_fde (fde_table
, fde
);
2010 /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
2011 expect an FDE or a CIE. */
2013 static const gdb_byte
*
2014 decode_frame_entry (struct comp_unit
*unit
, const gdb_byte
*start
,
2016 dwarf2_cie_table
&cie_table
,
2017 struct dwarf2_fde_table
*fde_table
,
2018 enum eh_frame_type entry_type
)
2020 enum { NONE
, ALIGN4
, ALIGN8
, FAIL
} workaround
= NONE
;
2021 const gdb_byte
*ret
;
2022 ptrdiff_t start_offset
;
2026 ret
= decode_frame_entry_1 (unit
, start
, eh_frame_p
,
2027 cie_table
, fde_table
, entry_type
);
2031 /* We have corrupt input data of some form. */
2033 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
2034 and mismatches wrt padding and alignment of debug sections. */
2035 /* Note that there is no requirement in the standard for any
2036 alignment at all in the frame unwind sections. Testing for
2037 alignment before trying to interpret data would be incorrect.
2039 However, GCC traditionally arranged for frame sections to be
2040 sized such that the FDE length and CIE fields happen to be
2041 aligned (in theory, for performance). This, unfortunately,
2042 was done with .align directives, which had the side effect of
2043 forcing the section to be aligned by the linker.
2045 This becomes a problem when you have some other producer that
2046 creates frame sections that are not as strictly aligned. That
2047 produces a hole in the frame info that gets filled by the
2050 The GCC behaviour is arguably a bug, but it's effectively now
2051 part of the ABI, so we're now stuck with it, at least at the
2052 object file level. A smart linker may decide, in the process
2053 of compressing duplicate CIE information, that it can rewrite
2054 the entire output section without this extra padding. */
2056 start_offset
= start
- unit
->dwarf_frame_buffer
;
2057 if (workaround
< ALIGN4
&& (start_offset
& 3) != 0)
2059 start
+= 4 - (start_offset
& 3);
2060 workaround
= ALIGN4
;
2063 if (workaround
< ALIGN8
&& (start_offset
& 7) != 0)
2065 start
+= 8 - (start_offset
& 7);
2066 workaround
= ALIGN8
;
2070 /* Nothing left to try. Arrange to return as if we've consumed
2071 the entire input section. Hopefully we'll get valid info from
2072 the other of .debug_frame/.eh_frame. */
2074 ret
= unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
;
2085 Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
2086 unit
->dwarf_frame_section
->owner
->filename
,
2087 unit
->dwarf_frame_section
->name
);
2092 Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
2093 unit
->dwarf_frame_section
->owner
->filename
,
2094 unit
->dwarf_frame_section
->name
);
2098 complaint (_("Corrupt data in %s:%s"),
2099 unit
->dwarf_frame_section
->owner
->filename
,
2100 unit
->dwarf_frame_section
->name
);
2108 fde_is_less_than (const dwarf2_fde
*aa
, const dwarf2_fde
*bb
)
2110 if (aa
->initial_location
== bb
->initial_location
)
2112 if (aa
->address_range
!= bb
->address_range
2113 && aa
->eh_frame_p
== 0 && bb
->eh_frame_p
== 0)
2114 /* Linker bug, e.g. gold/10400.
2115 Work around it by keeping stable sort order. */
2118 /* Put eh_frame entries after debug_frame ones. */
2119 return aa
->eh_frame_p
< bb
->eh_frame_p
;
2122 return aa
->initial_location
< bb
->initial_location
;
2126 dwarf2_build_frame_info (struct objfile
*objfile
)
2128 struct comp_unit
*unit
;
2129 const gdb_byte
*frame_ptr
;
2130 dwarf2_cie_table cie_table
;
2131 struct dwarf2_fde_table fde_table
;
2132 struct dwarf2_fde_table
*fde_table2
;
2134 fde_table
.num_entries
= 0;
2135 fde_table
.entries
= NULL
;
2137 /* Build a minimal decoding of the DWARF2 compilation unit. */
2138 unit
= XOBNEW (&objfile
->objfile_obstack
, comp_unit
);
2139 unit
->abfd
= objfile
->obfd
;
2140 unit
->objfile
= objfile
;
2144 if (objfile
->separate_debug_objfile_backlink
== NULL
)
2146 /* Do not read .eh_frame from separate file as they must be also
2147 present in the main file. */
2148 dwarf2_get_section_info (objfile
, DWARF2_EH_FRAME
,
2149 &unit
->dwarf_frame_section
,
2150 &unit
->dwarf_frame_buffer
,
2151 &unit
->dwarf_frame_size
);
2152 if (unit
->dwarf_frame_size
)
2154 asection
*got
, *txt
;
2156 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2157 that is used for the i386/amd64 target, which currently is
2158 the only target in GCC that supports/uses the
2159 DW_EH_PE_datarel encoding. */
2160 got
= bfd_get_section_by_name (unit
->abfd
, ".got");
2162 unit
->dbase
= got
->vma
;
2164 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2166 txt
= bfd_get_section_by_name (unit
->abfd
, ".text");
2168 unit
->tbase
= txt
->vma
;
2172 frame_ptr
= unit
->dwarf_frame_buffer
;
2173 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2174 frame_ptr
= decode_frame_entry (unit
, frame_ptr
, 1,
2175 cie_table
, &fde_table
,
2176 EH_CIE_OR_FDE_TYPE_ID
);
2179 catch (const gdb_exception_error
&e
)
2181 warning (_("skipping .eh_frame info of %s: %s"),
2182 objfile_name (objfile
), e
.what ());
2184 if (fde_table
.num_entries
!= 0)
2186 xfree (fde_table
.entries
);
2187 fde_table
.entries
= NULL
;
2188 fde_table
.num_entries
= 0;
2190 /* The cie_table is discarded below. */
2197 dwarf2_get_section_info (objfile
, DWARF2_DEBUG_FRAME
,
2198 &unit
->dwarf_frame_section
,
2199 &unit
->dwarf_frame_buffer
,
2200 &unit
->dwarf_frame_size
);
2201 if (unit
->dwarf_frame_size
)
2203 int num_old_fde_entries
= fde_table
.num_entries
;
2207 frame_ptr
= unit
->dwarf_frame_buffer
;
2208 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2209 frame_ptr
= decode_frame_entry (unit
, frame_ptr
, 0,
2210 cie_table
, &fde_table
,
2211 EH_CIE_OR_FDE_TYPE_ID
);
2213 catch (const gdb_exception_error
&e
)
2215 warning (_("skipping .debug_frame info of %s: %s"),
2216 objfile_name (objfile
), e
.what ());
2218 if (fde_table
.num_entries
!= 0)
2220 fde_table
.num_entries
= num_old_fde_entries
;
2221 if (num_old_fde_entries
== 0)
2223 xfree (fde_table
.entries
);
2224 fde_table
.entries
= NULL
;
2229 = XRESIZEVEC (struct dwarf2_fde
*, fde_table
.entries
,
2230 fde_table
.num_entries
);
2233 fde_table
.num_entries
= num_old_fde_entries
;
2237 /* Copy fde_table to obstack: it is needed at runtime. */
2238 fde_table2
= XOBNEW (&objfile
->objfile_obstack
, struct dwarf2_fde_table
);
2240 if (fde_table
.num_entries
== 0)
2242 fde_table2
->entries
= NULL
;
2243 fde_table2
->num_entries
= 0;
2247 struct dwarf2_fde
*fde_prev
= NULL
;
2248 struct dwarf2_fde
*first_non_zero_fde
= NULL
;
2251 /* Prepare FDE table for lookups. */
2252 std::sort (fde_table
.entries
, fde_table
.entries
+ fde_table
.num_entries
,
2255 /* Check for leftovers from --gc-sections. The GNU linker sets
2256 the relevant symbols to zero, but doesn't zero the FDE *end*
2257 ranges because there's no relocation there. It's (offset,
2258 length), not (start, end). On targets where address zero is
2259 just another valid address this can be a problem, since the
2260 FDEs appear to be non-empty in the output --- we could pick
2261 out the wrong FDE. To work around this, when overlaps are
2262 detected, we prefer FDEs that do not start at zero.
2264 Start by finding the first FDE with non-zero start. Below
2265 we'll discard all FDEs that start at zero and overlap this
2267 for (i
= 0; i
< fde_table
.num_entries
; i
++)
2269 struct dwarf2_fde
*fde
= fde_table
.entries
[i
];
2271 if (fde
->initial_location
!= 0)
2273 first_non_zero_fde
= fde
;
2278 /* Since we'll be doing bsearch, squeeze out identical (except
2279 for eh_frame_p) fde entries so bsearch result is predictable.
2280 Also discard leftovers from --gc-sections. */
2281 fde_table2
->num_entries
= 0;
2282 for (i
= 0; i
< fde_table
.num_entries
; i
++)
2284 struct dwarf2_fde
*fde
= fde_table
.entries
[i
];
2286 if (fde
->initial_location
== 0
2287 && first_non_zero_fde
!= NULL
2288 && (first_non_zero_fde
->initial_location
2289 < fde
->initial_location
+ fde
->address_range
))
2292 if (fde_prev
!= NULL
2293 && fde_prev
->initial_location
== fde
->initial_location
)
2296 obstack_grow (&objfile
->objfile_obstack
, &fde_table
.entries
[i
],
2297 sizeof (fde_table
.entries
[0]));
2298 ++fde_table2
->num_entries
;
2302 = (struct dwarf2_fde
**) obstack_finish (&objfile
->objfile_obstack
);
2304 /* Discard the original fde_table. */
2305 xfree (fde_table
.entries
);
2308 dwarf2_frame_objfile_data
.set (objfile
, fde_table2
);
2311 /* Handle 'maintenance show dwarf unwinders'. */
2314 show_dwarf_unwinders_enabled_p (struct ui_file
*file
, int from_tty
,
2315 struct cmd_list_element
*c
,
2318 fprintf_filtered (file
,
2319 _("The DWARF stack unwinders are currently %s.\n"),
2323 void _initialize_dwarf2_frame ();
2325 _initialize_dwarf2_frame ()
2327 dwarf2_frame_data
= gdbarch_data_register_pre_init (dwarf2_frame_init
);
2329 add_setshow_boolean_cmd ("unwinders", class_obscure
,
2330 &dwarf2_frame_unwinders_enabled_p
, _("\
2331 Set whether the DWARF stack frame unwinders are used."), _("\
2332 Show whether the DWARF stack frame unwinders are used."), _("\
2333 When enabled the DWARF stack frame unwinders can be used for architectures\n\
2334 that support the DWARF unwinders. Enabling the DWARF unwinders for an\n\
2335 architecture that doesn't support them will have no effect."),
2337 show_dwarf_unwinders_enabled_p
,
2339 &show_dwarf_cmdlist
);
2342 selftests::register_test_foreach_arch ("execute_cfa_program",
2343 selftests::execute_cfa_program_test
);