1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
6 Contributed by Mark Kettenis.
8 This file is part of GDB.
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program. If not, see <http://www.gnu.org/licenses/>. */
24 #include "dwarf2expr.h"
27 #include "frame-base.h"
28 #include "frame-unwind.h"
36 #include "gdb_assert.h"
37 #include "gdb_string.h"
39 #include "complaints.h"
40 #include "dwarf2-frame.h"
44 /* Call Frame Information (CFI). */
46 /* Common Information Entry (CIE). */
50 /* Computation Unit for this CIE. */
51 struct comp_unit
*unit
;
53 /* Offset into the .debug_frame section where this CIE was found.
54 Used to identify this CIE. */
57 /* Constant that is factored out of all advance location
59 ULONGEST code_alignment_factor
;
61 /* Constants that is factored out of all offset instructions. */
62 LONGEST data_alignment_factor
;
64 /* Return address column. */
65 ULONGEST return_address_register
;
67 /* Instruction sequence to initialize a register set. */
68 gdb_byte
*initial_instructions
;
71 /* Saved augmentation, in case it's needed later. */
74 /* Encoding of addresses. */
77 /* Target address size in bytes. */
80 /* True if a 'z' augmentation existed. */
81 unsigned char saw_z_augmentation
;
83 /* True if an 'S' augmentation existed. */
84 unsigned char signal_frame
;
86 /* The version recorded in the CIE. */
87 unsigned char version
;
90 struct dwarf2_cie_table
93 struct dwarf2_cie
**entries
;
96 /* Frame Description Entry (FDE). */
100 /* CIE for this FDE. */
101 struct dwarf2_cie
*cie
;
103 /* First location associated with this FDE. */
104 CORE_ADDR initial_location
;
106 /* Number of bytes of program instructions described by this FDE. */
107 CORE_ADDR address_range
;
109 /* Instruction sequence. */
110 gdb_byte
*instructions
;
113 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
115 unsigned char eh_frame_p
;
118 struct dwarf2_fde_table
121 struct dwarf2_fde
**entries
;
124 /* A minimal decoding of DWARF2 compilation units. We only decode
125 what's needed to get to the call frame information. */
129 /* Keep the bfd convenient. */
132 struct objfile
*objfile
;
134 /* Pointer to the .debug_frame section loaded into memory. */
135 gdb_byte
*dwarf_frame_buffer
;
137 /* Length of the loaded .debug_frame section. */
138 bfd_size_type dwarf_frame_size
;
140 /* Pointer to the .debug_frame section. */
141 asection
*dwarf_frame_section
;
143 /* Base for DW_EH_PE_datarel encodings. */
146 /* Base for DW_EH_PE_textrel encodings. */
150 static struct dwarf2_fde
*dwarf2_frame_find_fde (CORE_ADDR
*pc
);
152 static int dwarf2_frame_adjust_regnum (struct gdbarch
*gdbarch
, int regnum
,
155 static CORE_ADDR
read_encoded_value (struct comp_unit
*unit
, gdb_byte encoding
,
156 int ptr_len
, gdb_byte
*buf
,
157 unsigned int *bytes_read_ptr
,
158 CORE_ADDR func_base
);
161 /* Structure describing a frame state. */
163 struct dwarf2_frame_state
165 /* Each register save state can be described in terms of a CFA slot,
166 another register, or a location expression. */
167 struct dwarf2_frame_state_reg_info
169 struct dwarf2_frame_state_reg
*reg
;
181 /* Used to implement DW_CFA_remember_state. */
182 struct dwarf2_frame_state_reg_info
*prev
;
185 /* The PC described by the current frame state. */
188 /* Initial register set from the CIE.
189 Used to implement DW_CFA_restore. */
190 struct dwarf2_frame_state_reg_info initial
;
192 /* The information we care about from the CIE. */
195 ULONGEST retaddr_column
;
197 /* Flags for known producer quirks. */
199 /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa
200 and DW_CFA_def_cfa_offset takes a factored offset. */
201 int armcc_cfa_offsets_sf
;
203 /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
204 the CFA is defined as REG - OFFSET rather than REG + OFFSET. */
205 int armcc_cfa_offsets_reversed
;
208 /* Store the length the expression for the CFA in the `cfa_reg' field,
209 which is unused in that case. */
210 #define cfa_exp_len cfa_reg
212 /* Assert that the register set RS is large enough to store gdbarch_num_regs
213 columns. If necessary, enlarge the register set. */
216 dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info
*rs
,
219 size_t size
= sizeof (struct dwarf2_frame_state_reg
);
221 if (num_regs
<= rs
->num_regs
)
224 rs
->reg
= (struct dwarf2_frame_state_reg
*)
225 xrealloc (rs
->reg
, num_regs
* size
);
227 /* Initialize newly allocated registers. */
228 memset (rs
->reg
+ rs
->num_regs
, 0, (num_regs
- rs
->num_regs
) * size
);
229 rs
->num_regs
= num_regs
;
232 /* Copy the register columns in register set RS into newly allocated
233 memory and return a pointer to this newly created copy. */
235 static struct dwarf2_frame_state_reg
*
236 dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info
*rs
)
238 size_t size
= rs
->num_regs
* sizeof (struct dwarf2_frame_state_reg
);
239 struct dwarf2_frame_state_reg
*reg
;
241 reg
= (struct dwarf2_frame_state_reg
*) xmalloc (size
);
242 memcpy (reg
, rs
->reg
, size
);
247 /* Release the memory allocated to register set RS. */
250 dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info
*rs
)
254 dwarf2_frame_state_free_regs (rs
->prev
);
261 /* Release the memory allocated to the frame state FS. */
264 dwarf2_frame_state_free (void *p
)
266 struct dwarf2_frame_state
*fs
= p
;
268 dwarf2_frame_state_free_regs (fs
->initial
.prev
);
269 dwarf2_frame_state_free_regs (fs
->regs
.prev
);
270 xfree (fs
->initial
.reg
);
271 xfree (fs
->regs
.reg
);
276 /* Helper functions for execute_stack_op. */
279 read_reg (void *baton
, int reg
)
281 struct frame_info
*this_frame
= (struct frame_info
*) baton
;
282 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
286 regnum
= gdbarch_dwarf2_reg_to_regnum (gdbarch
, reg
);
288 buf
= alloca (register_size (gdbarch
, regnum
));
289 get_frame_register (this_frame
, regnum
, buf
);
291 /* Convert the register to an integer. This returns a LONGEST
292 rather than a CORE_ADDR, but unpack_pointer does the same thing
293 under the covers, and this makes more sense for non-pointer
294 registers. Maybe read_reg and the associated interfaces should
295 deal with "struct value" instead of CORE_ADDR. */
296 return unpack_long (register_type (gdbarch
, regnum
), buf
);
300 read_mem (void *baton
, gdb_byte
*buf
, CORE_ADDR addr
, size_t len
)
302 read_memory (addr
, buf
, len
);
306 no_get_frame_base (void *baton
, gdb_byte
**start
, size_t *length
)
308 internal_error (__FILE__
, __LINE__
,
309 _("Support for DW_OP_fbreg is unimplemented"));
312 /* Helper function for execute_stack_op. */
315 no_get_frame_cfa (void *baton
)
317 internal_error (__FILE__
, __LINE__
,
318 _("Support for DW_OP_call_frame_cfa is unimplemented"));
322 no_get_tls_address (void *baton
, CORE_ADDR offset
)
324 internal_error (__FILE__
, __LINE__
,
325 _("Support for DW_OP_GNU_push_tls_address is unimplemented"));
328 /* Execute the required actions for both the DW_CFA_restore and
329 DW_CFA_restore_extended instructions. */
331 dwarf2_restore_rule (struct gdbarch
*gdbarch
, ULONGEST reg_num
,
332 struct dwarf2_frame_state
*fs
, int eh_frame_p
)
336 gdb_assert (fs
->initial
.reg
);
337 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg_num
, eh_frame_p
);
338 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
340 /* Check if this register was explicitly initialized in the
341 CIE initial instructions. If not, default the rule to
343 if (reg
< fs
->initial
.num_regs
)
344 fs
->regs
.reg
[reg
] = fs
->initial
.reg
[reg
];
346 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNSPECIFIED
;
348 if (fs
->regs
.reg
[reg
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
349 complaint (&symfile_complaints
, _("\
350 incomplete CFI data; DW_CFA_restore unspecified\n\
351 register %s (#%d) at %s"),
352 gdbarch_register_name
353 (gdbarch
, gdbarch_dwarf2_reg_to_regnum (gdbarch
, reg
)),
354 gdbarch_dwarf2_reg_to_regnum (gdbarch
, reg
),
355 paddress (gdbarch
, fs
->pc
));
359 execute_stack_op (gdb_byte
*exp
, ULONGEST len
, int addr_size
,
360 struct frame_info
*this_frame
, CORE_ADDR initial
,
361 int initial_in_stack_memory
)
363 struct dwarf_expr_context
*ctx
;
365 struct cleanup
*old_chain
;
367 ctx
= new_dwarf_expr_context ();
368 old_chain
= make_cleanup_free_dwarf_expr_context (ctx
);
370 ctx
->gdbarch
= get_frame_arch (this_frame
);
371 ctx
->addr_size
= addr_size
;
372 ctx
->baton
= this_frame
;
373 ctx
->read_reg
= read_reg
;
374 ctx
->read_mem
= read_mem
;
375 ctx
->get_frame_base
= no_get_frame_base
;
376 ctx
->get_frame_cfa
= no_get_frame_cfa
;
377 ctx
->get_tls_address
= no_get_tls_address
;
379 dwarf_expr_push (ctx
, initial
, initial_in_stack_memory
);
380 dwarf_expr_eval (ctx
, exp
, len
);
381 result
= dwarf_expr_fetch (ctx
, 0);
383 if (ctx
->location
== DWARF_VALUE_REGISTER
)
384 result
= read_reg (this_frame
, result
);
385 else if (ctx
->location
!= DWARF_VALUE_MEMORY
)
387 /* This is actually invalid DWARF, but if we ever do run across
388 it somehow, we might as well support it. So, instead, report
389 it as unimplemented. */
390 error (_("Not implemented: computing unwound register using explicit value operator"));
393 do_cleanups (old_chain
);
400 execute_cfa_program (struct dwarf2_fde
*fde
, gdb_byte
*insn_ptr
,
401 gdb_byte
*insn_end
, struct frame_info
*this_frame
,
402 struct dwarf2_frame_state
*fs
)
404 int eh_frame_p
= fde
->eh_frame_p
;
405 CORE_ADDR pc
= get_frame_pc (this_frame
);
407 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
408 enum bfd_endian byte_order
= gdbarch_byte_order (gdbarch
);
410 while (insn_ptr
< insn_end
&& fs
->pc
<= pc
)
412 gdb_byte insn
= *insn_ptr
++;
416 if ((insn
& 0xc0) == DW_CFA_advance_loc
)
417 fs
->pc
+= (insn
& 0x3f) * fs
->code_align
;
418 else if ((insn
& 0xc0) == DW_CFA_offset
)
421 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
422 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
423 offset
= utmp
* fs
->data_align
;
424 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
425 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
426 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
428 else if ((insn
& 0xc0) == DW_CFA_restore
)
431 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
438 fs
->pc
= read_encoded_value (fde
->cie
->unit
, fde
->cie
->encoding
,
439 fde
->cie
->addr_size
, insn_ptr
,
440 &bytes_read
, fde
->initial_location
);
441 /* Apply the objfile offset for relocatable objects. */
442 fs
->pc
+= ANOFFSET (fde
->cie
->unit
->objfile
->section_offsets
,
443 SECT_OFF_TEXT (fde
->cie
->unit
->objfile
));
444 insn_ptr
+= bytes_read
;
447 case DW_CFA_advance_loc1
:
448 utmp
= extract_unsigned_integer (insn_ptr
, 1, byte_order
);
449 fs
->pc
+= utmp
* fs
->code_align
;
452 case DW_CFA_advance_loc2
:
453 utmp
= extract_unsigned_integer (insn_ptr
, 2, byte_order
);
454 fs
->pc
+= utmp
* fs
->code_align
;
457 case DW_CFA_advance_loc4
:
458 utmp
= extract_unsigned_integer (insn_ptr
, 4, byte_order
);
459 fs
->pc
+= utmp
* fs
->code_align
;
463 case DW_CFA_offset_extended
:
464 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
465 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
466 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
467 offset
= utmp
* fs
->data_align
;
468 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
469 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
470 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
473 case DW_CFA_restore_extended
:
474 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
475 dwarf2_restore_rule (gdbarch
, reg
, fs
, eh_frame_p
);
478 case DW_CFA_undefined
:
479 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
480 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
481 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
482 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNDEFINED
;
485 case DW_CFA_same_value
:
486 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
487 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
488 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
489 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAME_VALUE
;
492 case DW_CFA_register
:
493 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
494 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
495 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
496 utmp
= dwarf2_frame_adjust_regnum (gdbarch
, utmp
, eh_frame_p
);
497 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
498 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_REG
;
499 fs
->regs
.reg
[reg
].loc
.reg
= utmp
;
502 case DW_CFA_remember_state
:
504 struct dwarf2_frame_state_reg_info
*new_rs
;
506 new_rs
= XMALLOC (struct dwarf2_frame_state_reg_info
);
508 fs
->regs
.reg
= dwarf2_frame_state_copy_regs (&fs
->regs
);
509 fs
->regs
.prev
= new_rs
;
513 case DW_CFA_restore_state
:
515 struct dwarf2_frame_state_reg_info
*old_rs
= fs
->regs
.prev
;
519 complaint (&symfile_complaints
, _("\
520 bad CFI data; mismatched DW_CFA_restore_state at %s"),
521 paddress (gdbarch
, fs
->pc
));
525 xfree (fs
->regs
.reg
);
533 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &fs
->regs
.cfa_reg
);
534 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
536 if (fs
->armcc_cfa_offsets_sf
)
537 utmp
*= fs
->data_align
;
539 fs
->regs
.cfa_offset
= utmp
;
540 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
543 case DW_CFA_def_cfa_register
:
544 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &fs
->regs
.cfa_reg
);
545 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
,
548 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
551 case DW_CFA_def_cfa_offset
:
552 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
554 if (fs
->armcc_cfa_offsets_sf
)
555 utmp
*= fs
->data_align
;
557 fs
->regs
.cfa_offset
= utmp
;
558 /* cfa_how deliberately not set. */
564 case DW_CFA_def_cfa_expression
:
565 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
,
566 &fs
->regs
.cfa_exp_len
);
567 fs
->regs
.cfa_exp
= insn_ptr
;
568 fs
->regs
.cfa_how
= CFA_EXP
;
569 insn_ptr
+= fs
->regs
.cfa_exp_len
;
572 case DW_CFA_expression
:
573 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
574 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
575 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
576 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
577 fs
->regs
.reg
[reg
].loc
.exp
= insn_ptr
;
578 fs
->regs
.reg
[reg
].exp_len
= utmp
;
579 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_EXP
;
583 case DW_CFA_offset_extended_sf
:
584 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
585 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
586 insn_ptr
= read_sleb128 (insn_ptr
, insn_end
, &offset
);
587 offset
*= fs
->data_align
;
588 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
589 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
590 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
593 case DW_CFA_val_offset
:
594 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
595 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
596 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
597 offset
= utmp
* fs
->data_align
;
598 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_OFFSET
;
599 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
602 case DW_CFA_val_offset_sf
:
603 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
604 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
605 insn_ptr
= read_sleb128 (insn_ptr
, insn_end
, &offset
);
606 offset
*= fs
->data_align
;
607 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_OFFSET
;
608 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
611 case DW_CFA_val_expression
:
612 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
613 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
614 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
615 fs
->regs
.reg
[reg
].loc
.exp
= insn_ptr
;
616 fs
->regs
.reg
[reg
].exp_len
= utmp
;
617 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_VAL_EXP
;
621 case DW_CFA_def_cfa_sf
:
622 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &fs
->regs
.cfa_reg
);
623 fs
->regs
.cfa_reg
= dwarf2_frame_adjust_regnum (gdbarch
,
626 insn_ptr
= read_sleb128 (insn_ptr
, insn_end
, &offset
);
627 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
628 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
631 case DW_CFA_def_cfa_offset_sf
:
632 insn_ptr
= read_sleb128 (insn_ptr
, insn_end
, &offset
);
633 fs
->regs
.cfa_offset
= offset
* fs
->data_align
;
634 /* cfa_how deliberately not set. */
637 case DW_CFA_GNU_window_save
:
638 /* This is SPARC-specific code, and contains hard-coded
639 constants for the register numbering scheme used by
640 GCC. Rather than having a architecture-specific
641 operation that's only ever used by a single
642 architecture, we provide the implementation here.
643 Incidentally that's what GCC does too in its
646 int size
= register_size (gdbarch
, 0);
647 dwarf2_frame_state_alloc_regs (&fs
->regs
, 32);
648 for (reg
= 8; reg
< 16; reg
++)
650 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_REG
;
651 fs
->regs
.reg
[reg
].loc
.reg
= reg
+ 16;
653 for (reg
= 16; reg
< 32; reg
++)
655 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
656 fs
->regs
.reg
[reg
].loc
.offset
= (reg
- 16) * size
;
661 case DW_CFA_GNU_args_size
:
663 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
666 case DW_CFA_GNU_negative_offset_extended
:
667 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
668 reg
= dwarf2_frame_adjust_regnum (gdbarch
, reg
, eh_frame_p
);
669 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &offset
);
670 offset
*= fs
->data_align
;
671 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
672 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
673 fs
->regs
.reg
[reg
].loc
.offset
= -offset
;
677 internal_error (__FILE__
, __LINE__
, _("Unknown CFI encountered."));
682 /* Don't allow remember/restore between CIE and FDE programs. */
683 dwarf2_frame_state_free_regs (fs
->regs
.prev
);
684 fs
->regs
.prev
= NULL
;
688 /* Architecture-specific operations. */
690 /* Per-architecture data key. */
691 static struct gdbarch_data
*dwarf2_frame_data
;
693 struct dwarf2_frame_ops
695 /* Pre-initialize the register state REG for register REGNUM. */
696 void (*init_reg
) (struct gdbarch
*, int, struct dwarf2_frame_state_reg
*,
697 struct frame_info
*);
699 /* Check whether the THIS_FRAME is a signal trampoline. */
700 int (*signal_frame_p
) (struct gdbarch
*, struct frame_info
*);
702 /* Convert .eh_frame register number to DWARF register number, or
703 adjust .debug_frame register number. */
704 int (*adjust_regnum
) (struct gdbarch
*, int, int);
707 /* Default architecture-specific register state initialization
711 dwarf2_frame_default_init_reg (struct gdbarch
*gdbarch
, int regnum
,
712 struct dwarf2_frame_state_reg
*reg
,
713 struct frame_info
*this_frame
)
715 /* If we have a register that acts as a program counter, mark it as
716 a destination for the return address. If we have a register that
717 serves as the stack pointer, arrange for it to be filled with the
718 call frame address (CFA). The other registers are marked as
721 We copy the return address to the program counter, since many
722 parts in GDB assume that it is possible to get the return address
723 by unwinding the program counter register. However, on ISA's
724 with a dedicated return address register, the CFI usually only
725 contains information to unwind that return address register.
727 The reason we're treating the stack pointer special here is
728 because in many cases GCC doesn't emit CFI for the stack pointer
729 and implicitly assumes that it is equal to the CFA. This makes
730 some sense since the DWARF specification (version 3, draft 8,
733 "Typically, the CFA is defined to be the value of the stack
734 pointer at the call site in the previous frame (which may be
735 different from its value on entry to the current frame)."
737 However, this isn't true for all platforms supported by GCC
738 (e.g. IBM S/390 and zSeries). Those architectures should provide
739 their own architecture-specific initialization function. */
741 if (regnum
== gdbarch_pc_regnum (gdbarch
))
742 reg
->how
= DWARF2_FRAME_REG_RA
;
743 else if (regnum
== gdbarch_sp_regnum (gdbarch
))
744 reg
->how
= DWARF2_FRAME_REG_CFA
;
747 /* Return a default for the architecture-specific operations. */
750 dwarf2_frame_init (struct obstack
*obstack
)
752 struct dwarf2_frame_ops
*ops
;
754 ops
= OBSTACK_ZALLOC (obstack
, struct dwarf2_frame_ops
);
755 ops
->init_reg
= dwarf2_frame_default_init_reg
;
759 /* Set the architecture-specific register state initialization
760 function for GDBARCH to INIT_REG. */
763 dwarf2_frame_set_init_reg (struct gdbarch
*gdbarch
,
764 void (*init_reg
) (struct gdbarch
*, int,
765 struct dwarf2_frame_state_reg
*,
766 struct frame_info
*))
768 struct dwarf2_frame_ops
*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
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
782 ops
->init_reg (gdbarch
, regnum
, reg
, this_frame
);
785 /* Set the architecture-specific signal trampoline recognition
786 function for GDBARCH to SIGNAL_FRAME_P. */
789 dwarf2_frame_set_signal_frame_p (struct gdbarch
*gdbarch
,
790 int (*signal_frame_p
) (struct gdbarch
*,
791 struct frame_info
*))
793 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
795 ops
->signal_frame_p
= signal_frame_p
;
798 /* Query the architecture-specific signal frame recognizer for
802 dwarf2_frame_signal_frame_p (struct gdbarch
*gdbarch
,
803 struct frame_info
*this_frame
)
805 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
807 if (ops
->signal_frame_p
== NULL
)
809 return ops
->signal_frame_p (gdbarch
, this_frame
);
812 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
816 dwarf2_frame_set_adjust_regnum (struct gdbarch
*gdbarch
,
817 int (*adjust_regnum
) (struct gdbarch
*,
820 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
822 ops
->adjust_regnum
= adjust_regnum
;
825 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
829 dwarf2_frame_adjust_regnum (struct gdbarch
*gdbarch
, int regnum
, int eh_frame_p
)
831 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
833 if (ops
->adjust_regnum
== NULL
)
835 return ops
->adjust_regnum (gdbarch
, regnum
, eh_frame_p
);
839 dwarf2_frame_find_quirks (struct dwarf2_frame_state
*fs
,
840 struct dwarf2_fde
*fde
)
844 s
= find_pc_symtab (fs
->pc
);
848 if (producer_is_realview (s
->producer
))
850 if (fde
->cie
->version
== 1)
851 fs
->armcc_cfa_offsets_sf
= 1;
853 if (fde
->cie
->version
== 1)
854 fs
->armcc_cfa_offsets_reversed
= 1;
856 /* The reversed offset problem is present in some compilers
857 using DWARF3, but it was eventually fixed. Check the ARM
858 defined augmentations, which are in the format "armcc" followed
859 by a list of one-character options. The "+" option means
860 this problem is fixed (no quirk needed). If the armcc
861 augmentation is missing, the quirk is needed. */
862 if (fde
->cie
->version
== 3
863 && (strncmp (fde
->cie
->augmentation
, "armcc", 5) != 0
864 || strchr (fde
->cie
->augmentation
+ 5, '+') == NULL
))
865 fs
->armcc_cfa_offsets_reversed
= 1;
872 struct dwarf2_frame_cache
874 /* DWARF Call Frame Address. */
877 /* Set if the return address column was marked as undefined. */
878 int undefined_retaddr
;
880 /* Saved registers, indexed by GDB register number, not by DWARF
882 struct dwarf2_frame_state_reg
*reg
;
884 /* Return address register. */
885 struct dwarf2_frame_state_reg retaddr_reg
;
887 /* Target address size in bytes. */
891 static struct dwarf2_frame_cache
*
892 dwarf2_frame_cache (struct frame_info
*this_frame
, void **this_cache
)
894 struct cleanup
*old_chain
;
895 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
896 const int num_regs
= gdbarch_num_regs (gdbarch
)
897 + gdbarch_num_pseudo_regs (gdbarch
);
898 struct dwarf2_frame_cache
*cache
;
899 struct dwarf2_frame_state
*fs
;
900 struct dwarf2_fde
*fde
;
905 /* Allocate a new cache. */
906 cache
= FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache
);
907 cache
->reg
= FRAME_OBSTACK_CALLOC (num_regs
, struct dwarf2_frame_state_reg
);
909 /* Allocate and initialize the frame state. */
910 fs
= XMALLOC (struct dwarf2_frame_state
);
911 memset (fs
, 0, sizeof (struct dwarf2_frame_state
));
912 old_chain
= make_cleanup (dwarf2_frame_state_free
, fs
);
916 Note that if the next frame is never supposed to return (i.e. a call
917 to abort), the compiler might optimize away the instruction at
918 its return address. As a result the return address will
919 point at some random instruction, and the CFI for that
920 instruction is probably worthless to us. GCC's unwinder solves
921 this problem by substracting 1 from the return address to get an
922 address in the middle of a presumed call instruction (or the
923 instruction in the associated delay slot). This should only be
924 done for "normal" frames and not for resume-type frames (signal
925 handlers, sentinel frames, dummy frames). The function
926 get_frame_address_in_block does just this. It's not clear how
927 reliable the method is though; there is the potential for the
928 register state pre-call being different to that on return. */
929 fs
->pc
= get_frame_address_in_block (this_frame
);
931 /* Find the correct FDE. */
932 fde
= dwarf2_frame_find_fde (&fs
->pc
);
933 gdb_assert (fde
!= NULL
);
935 /* Extract any interesting information from the CIE. */
936 fs
->data_align
= fde
->cie
->data_alignment_factor
;
937 fs
->code_align
= fde
->cie
->code_alignment_factor
;
938 fs
->retaddr_column
= fde
->cie
->return_address_register
;
939 cache
->addr_size
= fde
->cie
->addr_size
;
941 /* Check for "quirks" - known bugs in producers. */
942 dwarf2_frame_find_quirks (fs
, fde
);
944 /* First decode all the insns in the CIE. */
945 execute_cfa_program (fde
, fde
->cie
->initial_instructions
,
946 fde
->cie
->end
, this_frame
, fs
);
948 /* Save the initialized register set. */
949 fs
->initial
= fs
->regs
;
950 fs
->initial
.reg
= dwarf2_frame_state_copy_regs (&fs
->regs
);
952 /* Then decode the insns in the FDE up to our target PC. */
953 execute_cfa_program (fde
, fde
->instructions
, fde
->end
, this_frame
, fs
);
955 /* Calculate the CFA. */
956 switch (fs
->regs
.cfa_how
)
959 cache
->cfa
= read_reg (this_frame
, fs
->regs
.cfa_reg
);
960 if (fs
->armcc_cfa_offsets_reversed
)
961 cache
->cfa
-= fs
->regs
.cfa_offset
;
963 cache
->cfa
+= fs
->regs
.cfa_offset
;
968 execute_stack_op (fs
->regs
.cfa_exp
, fs
->regs
.cfa_exp_len
,
969 cache
->addr_size
, this_frame
, 0, 0);
973 internal_error (__FILE__
, __LINE__
, _("Unknown CFA rule."));
976 /* Initialize the register state. */
980 for (regnum
= 0; regnum
< num_regs
; regnum
++)
981 dwarf2_frame_init_reg (gdbarch
, regnum
, &cache
->reg
[regnum
], this_frame
);
984 /* Go through the DWARF2 CFI generated table and save its register
985 location information in the cache. Note that we don't skip the
986 return address column; it's perfectly all right for it to
987 correspond to a real register. If it doesn't correspond to a
988 real register, or if we shouldn't treat it as such,
989 gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside
990 the range [0, gdbarch_num_regs). */
992 int column
; /* CFI speak for "register number". */
994 for (column
= 0; column
< fs
->regs
.num_regs
; column
++)
996 /* Use the GDB register number as the destination index. */
997 int regnum
= gdbarch_dwarf2_reg_to_regnum (gdbarch
, column
);
999 /* If there's no corresponding GDB register, ignore it. */
1000 if (regnum
< 0 || regnum
>= num_regs
)
1003 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1004 of all debug info registers. If it doesn't, complain (but
1005 not too loudly). It turns out that GCC assumes that an
1006 unspecified register implies "same value" when CFI (draft
1007 7) specifies nothing at all. Such a register could equally
1008 be interpreted as "undefined". Also note that this check
1009 isn't sufficient; it only checks that all registers in the
1010 range [0 .. max column] are specified, and won't detect
1011 problems when a debug info register falls outside of the
1012 table. We need a way of iterating through all the valid
1013 DWARF2 register numbers. */
1014 if (fs
->regs
.reg
[column
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
1016 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
1017 complaint (&symfile_complaints
, _("\
1018 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1019 gdbarch_register_name (gdbarch
, regnum
),
1020 paddress (gdbarch
, fs
->pc
));
1023 cache
->reg
[regnum
] = fs
->regs
.reg
[column
];
1027 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1028 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1032 for (regnum
= 0; regnum
< num_regs
; regnum
++)
1034 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
1035 || cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA_OFFSET
)
1037 struct dwarf2_frame_state_reg
*retaddr_reg
=
1038 &fs
->regs
.reg
[fs
->retaddr_column
];
1040 /* It seems rather bizarre to specify an "empty" column as
1041 the return adress column. However, this is exactly
1042 what GCC does on some targets. It turns out that GCC
1043 assumes that the return address can be found in the
1044 register corresponding to the return address column.
1045 Incidentally, that's how we should treat a return
1046 address column specifying "same value" too. */
1047 if (fs
->retaddr_column
< fs
->regs
.num_regs
1048 && retaddr_reg
->how
!= DWARF2_FRAME_REG_UNSPECIFIED
1049 && retaddr_reg
->how
!= DWARF2_FRAME_REG_SAME_VALUE
)
1051 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1052 cache
->reg
[regnum
] = *retaddr_reg
;
1054 cache
->retaddr_reg
= *retaddr_reg
;
1058 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
1060 cache
->reg
[regnum
].loc
.reg
= fs
->retaddr_column
;
1061 cache
->reg
[regnum
].how
= DWARF2_FRAME_REG_SAVED_REG
;
1065 cache
->retaddr_reg
.loc
.reg
= fs
->retaddr_column
;
1066 cache
->retaddr_reg
.how
= DWARF2_FRAME_REG_SAVED_REG
;
1073 if (fs
->retaddr_column
< fs
->regs
.num_regs
1074 && fs
->regs
.reg
[fs
->retaddr_column
].how
== DWARF2_FRAME_REG_UNDEFINED
)
1075 cache
->undefined_retaddr
= 1;
1077 do_cleanups (old_chain
);
1079 *this_cache
= cache
;
1084 dwarf2_frame_this_id (struct frame_info
*this_frame
, void **this_cache
,
1085 struct frame_id
*this_id
)
1087 struct dwarf2_frame_cache
*cache
=
1088 dwarf2_frame_cache (this_frame
, this_cache
);
1090 if (cache
->undefined_retaddr
)
1093 (*this_id
) = frame_id_build (cache
->cfa
, get_frame_func (this_frame
));
1096 static struct value
*
1097 dwarf2_frame_prev_register (struct frame_info
*this_frame
, void **this_cache
,
1100 struct gdbarch
*gdbarch
= get_frame_arch (this_frame
);
1101 struct dwarf2_frame_cache
*cache
=
1102 dwarf2_frame_cache (this_frame
, this_cache
);
1106 switch (cache
->reg
[regnum
].how
)
1108 case DWARF2_FRAME_REG_UNDEFINED
:
1109 /* If CFI explicitly specified that the value isn't defined,
1110 mark it as optimized away; the value isn't available. */
1111 return frame_unwind_got_optimized (this_frame
, regnum
);
1113 case DWARF2_FRAME_REG_SAVED_OFFSET
:
1114 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1115 return frame_unwind_got_memory (this_frame
, regnum
, addr
);
1117 case DWARF2_FRAME_REG_SAVED_REG
:
1119 = gdbarch_dwarf2_reg_to_regnum (gdbarch
, cache
->reg
[regnum
].loc
.reg
);
1120 return frame_unwind_got_register (this_frame
, regnum
, realnum
);
1122 case DWARF2_FRAME_REG_SAVED_EXP
:
1123 addr
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
,
1124 cache
->reg
[regnum
].exp_len
,
1125 cache
->addr_size
, this_frame
, cache
->cfa
, 1);
1126 return frame_unwind_got_memory (this_frame
, regnum
, addr
);
1128 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET
:
1129 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1130 return frame_unwind_got_constant (this_frame
, regnum
, addr
);
1132 case DWARF2_FRAME_REG_SAVED_VAL_EXP
:
1133 addr
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
,
1134 cache
->reg
[regnum
].exp_len
,
1135 cache
->addr_size
, this_frame
, cache
->cfa
, 1);
1136 return frame_unwind_got_constant (this_frame
, regnum
, addr
);
1138 case DWARF2_FRAME_REG_UNSPECIFIED
:
1139 /* GCC, in its infinite wisdom decided to not provide unwind
1140 information for registers that are "same value". Since
1141 DWARF2 (3 draft 7) doesn't define such behavior, said
1142 registers are actually undefined (which is different to CFI
1143 "undefined"). Code above issues a complaint about this.
1144 Here just fudge the books, assume GCC, and that the value is
1145 more inner on the stack. */
1146 return frame_unwind_got_register (this_frame
, regnum
, regnum
);
1148 case DWARF2_FRAME_REG_SAME_VALUE
:
1149 return frame_unwind_got_register (this_frame
, regnum
, regnum
);
1151 case DWARF2_FRAME_REG_CFA
:
1152 return frame_unwind_got_address (this_frame
, regnum
, cache
->cfa
);
1154 case DWARF2_FRAME_REG_CFA_OFFSET
:
1155 addr
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
1156 return frame_unwind_got_address (this_frame
, regnum
, addr
);
1158 case DWARF2_FRAME_REG_RA_OFFSET
:
1159 addr
= cache
->reg
[regnum
].loc
.offset
;
1160 regnum
= gdbarch_dwarf2_reg_to_regnum
1161 (gdbarch
, cache
->retaddr_reg
.loc
.reg
);
1162 addr
+= get_frame_register_unsigned (this_frame
, regnum
);
1163 return frame_unwind_got_address (this_frame
, regnum
, addr
);
1165 case DWARF2_FRAME_REG_FN
:
1166 return cache
->reg
[regnum
].loc
.fn (this_frame
, this_cache
, regnum
);
1169 internal_error (__FILE__
, __LINE__
, _("Unknown register rule."));
1174 dwarf2_frame_sniffer (const struct frame_unwind
*self
,
1175 struct frame_info
*this_frame
, void **this_cache
)
1177 /* Grab an address that is guarenteed to reside somewhere within the
1178 function. get_frame_pc(), with a no-return next function, can
1179 end up returning something past the end of this function's body.
1180 If the frame we're sniffing for is a signal frame whose start
1181 address is placed on the stack by the OS, its FDE must
1182 extend one byte before its start address or we could potentially
1183 select the FDE of the previous function. */
1184 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1185 struct dwarf2_fde
*fde
= dwarf2_frame_find_fde (&block_addr
);
1189 /* On some targets, signal trampolines may have unwind information.
1190 We need to recognize them so that we set the frame type
1193 if (fde
->cie
->signal_frame
1194 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame
),
1196 return self
->type
== SIGTRAMP_FRAME
;
1198 return self
->type
!= SIGTRAMP_FRAME
;
1201 static const struct frame_unwind dwarf2_frame_unwind
=
1204 dwarf2_frame_this_id
,
1205 dwarf2_frame_prev_register
,
1207 dwarf2_frame_sniffer
1210 static const struct frame_unwind dwarf2_signal_frame_unwind
=
1213 dwarf2_frame_this_id
,
1214 dwarf2_frame_prev_register
,
1216 dwarf2_frame_sniffer
1219 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1222 dwarf2_append_unwinders (struct gdbarch
*gdbarch
)
1224 frame_unwind_append_unwinder (gdbarch
, &dwarf2_frame_unwind
);
1225 frame_unwind_append_unwinder (gdbarch
, &dwarf2_signal_frame_unwind
);
1229 /* There is no explicitly defined relationship between the CFA and the
1230 location of frame's local variables and arguments/parameters.
1231 Therefore, frame base methods on this page should probably only be
1232 used as a last resort, just to avoid printing total garbage as a
1233 response to the "info frame" command. */
1236 dwarf2_frame_base_address (struct frame_info
*this_frame
, void **this_cache
)
1238 struct dwarf2_frame_cache
*cache
=
1239 dwarf2_frame_cache (this_frame
, this_cache
);
1244 static const struct frame_base dwarf2_frame_base
=
1246 &dwarf2_frame_unwind
,
1247 dwarf2_frame_base_address
,
1248 dwarf2_frame_base_address
,
1249 dwarf2_frame_base_address
1252 const struct frame_base
*
1253 dwarf2_frame_base_sniffer (struct frame_info
*this_frame
)
1255 CORE_ADDR block_addr
= get_frame_address_in_block (this_frame
);
1256 if (dwarf2_frame_find_fde (&block_addr
))
1257 return &dwarf2_frame_base
;
1262 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1263 the DWARF unwinder. This is used to implement
1264 DW_OP_call_frame_cfa. */
1267 dwarf2_frame_cfa (struct frame_info
*this_frame
)
1269 while (get_frame_type (this_frame
) == INLINE_FRAME
)
1270 this_frame
= get_prev_frame (this_frame
);
1271 /* This restriction could be lifted if other unwinders are known to
1272 compute the frame base in a way compatible with the DWARF
1274 if (! frame_unwinder_is (this_frame
, &dwarf2_frame_unwind
))
1275 error (_("can't compute CFA for this frame"));
1276 return get_frame_base (this_frame
);
1279 const struct objfile_data
*dwarf2_frame_objfile_data
;
1282 read_1_byte (bfd
*abfd
, gdb_byte
*buf
)
1284 return bfd_get_8 (abfd
, buf
);
1288 read_4_bytes (bfd
*abfd
, gdb_byte
*buf
)
1290 return bfd_get_32 (abfd
, buf
);
1294 read_8_bytes (bfd
*abfd
, gdb_byte
*buf
)
1296 return bfd_get_64 (abfd
, buf
);
1300 read_unsigned_leb128 (bfd
*abfd
, gdb_byte
*buf
, unsigned int *bytes_read_ptr
)
1303 unsigned int num_read
;
1313 byte
= bfd_get_8 (abfd
, (bfd_byte
*) buf
);
1316 result
|= ((byte
& 0x7f) << shift
);
1319 while (byte
& 0x80);
1321 *bytes_read_ptr
= num_read
;
1327 read_signed_leb128 (bfd
*abfd
, gdb_byte
*buf
, unsigned int *bytes_read_ptr
)
1331 unsigned int num_read
;
1340 byte
= bfd_get_8 (abfd
, (bfd_byte
*) buf
);
1343 result
|= ((byte
& 0x7f) << shift
);
1346 while (byte
& 0x80);
1348 if (shift
< 8 * sizeof (result
) && (byte
& 0x40))
1349 result
|= -(((LONGEST
)1) << shift
);
1351 *bytes_read_ptr
= num_read
;
1357 read_initial_length (bfd
*abfd
, gdb_byte
*buf
, unsigned int *bytes_read_ptr
)
1361 result
= bfd_get_32 (abfd
, buf
);
1362 if (result
== 0xffffffff)
1364 result
= bfd_get_64 (abfd
, buf
+ 4);
1365 *bytes_read_ptr
= 12;
1368 *bytes_read_ptr
= 4;
1374 /* Pointer encoding helper functions. */
1376 /* GCC supports exception handling based on DWARF2 CFI. However, for
1377 technical reasons, it encodes addresses in its FDE's in a different
1378 way. Several "pointer encodings" are supported. The encoding
1379 that's used for a particular FDE is determined by the 'R'
1380 augmentation in the associated CIE. The argument of this
1381 augmentation is a single byte.
1383 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1384 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1385 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1386 address should be interpreted (absolute, relative to the current
1387 position in the FDE, ...). Bit 7, indicates that the address
1388 should be dereferenced. */
1391 encoding_for_size (unsigned int size
)
1396 return DW_EH_PE_udata2
;
1398 return DW_EH_PE_udata4
;
1400 return DW_EH_PE_udata8
;
1402 internal_error (__FILE__
, __LINE__
, _("Unsupported address size"));
1407 read_encoded_value (struct comp_unit
*unit
, gdb_byte encoding
,
1408 int ptr_len
, gdb_byte
*buf
, unsigned int *bytes_read_ptr
,
1409 CORE_ADDR func_base
)
1414 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1416 if (encoding
& DW_EH_PE_indirect
)
1417 internal_error (__FILE__
, __LINE__
,
1418 _("Unsupported encoding: DW_EH_PE_indirect"));
1420 *bytes_read_ptr
= 0;
1422 switch (encoding
& 0x70)
1424 case DW_EH_PE_absptr
:
1427 case DW_EH_PE_pcrel
:
1428 base
= bfd_get_section_vma (unit
->abfd
, unit
->dwarf_frame_section
);
1429 base
+= (buf
- unit
->dwarf_frame_buffer
);
1431 case DW_EH_PE_datarel
:
1434 case DW_EH_PE_textrel
:
1437 case DW_EH_PE_funcrel
:
1440 case DW_EH_PE_aligned
:
1442 offset
= buf
- unit
->dwarf_frame_buffer
;
1443 if ((offset
% ptr_len
) != 0)
1445 *bytes_read_ptr
= ptr_len
- (offset
% ptr_len
);
1446 buf
+= *bytes_read_ptr
;
1450 internal_error (__FILE__
, __LINE__
, _("Invalid or unsupported encoding"));
1453 if ((encoding
& 0x07) == 0x00)
1455 encoding
|= encoding_for_size (ptr_len
);
1456 if (bfd_get_sign_extend_vma (unit
->abfd
))
1457 encoding
|= DW_EH_PE_signed
;
1460 switch (encoding
& 0x0f)
1462 case DW_EH_PE_uleb128
:
1465 gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1466 *bytes_read_ptr
+= read_uleb128 (buf
, end_buf
, &value
) - buf
;
1467 return base
+ value
;
1469 case DW_EH_PE_udata2
:
1470 *bytes_read_ptr
+= 2;
1471 return (base
+ bfd_get_16 (unit
->abfd
, (bfd_byte
*) buf
));
1472 case DW_EH_PE_udata4
:
1473 *bytes_read_ptr
+= 4;
1474 return (base
+ bfd_get_32 (unit
->abfd
, (bfd_byte
*) buf
));
1475 case DW_EH_PE_udata8
:
1476 *bytes_read_ptr
+= 8;
1477 return (base
+ bfd_get_64 (unit
->abfd
, (bfd_byte
*) buf
));
1478 case DW_EH_PE_sleb128
:
1481 gdb_byte
*end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1482 *bytes_read_ptr
+= read_sleb128 (buf
, end_buf
, &value
) - buf
;
1483 return base
+ value
;
1485 case DW_EH_PE_sdata2
:
1486 *bytes_read_ptr
+= 2;
1487 return (base
+ bfd_get_signed_16 (unit
->abfd
, (bfd_byte
*) buf
));
1488 case DW_EH_PE_sdata4
:
1489 *bytes_read_ptr
+= 4;
1490 return (base
+ bfd_get_signed_32 (unit
->abfd
, (bfd_byte
*) buf
));
1491 case DW_EH_PE_sdata8
:
1492 *bytes_read_ptr
+= 8;
1493 return (base
+ bfd_get_signed_64 (unit
->abfd
, (bfd_byte
*) buf
));
1495 internal_error (__FILE__
, __LINE__
, _("Invalid or unsupported encoding"));
1501 bsearch_cie_cmp (const void *key
, const void *element
)
1503 ULONGEST cie_pointer
= *(ULONGEST
*) key
;
1504 struct dwarf2_cie
*cie
= *(struct dwarf2_cie
**) element
;
1506 if (cie_pointer
== cie
->cie_pointer
)
1509 return (cie_pointer
< cie
->cie_pointer
) ? -1 : 1;
1512 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1513 static struct dwarf2_cie
*
1514 find_cie (struct dwarf2_cie_table
*cie_table
, ULONGEST cie_pointer
)
1516 struct dwarf2_cie
**p_cie
;
1518 /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
1519 bsearch be non-NULL. */
1520 if (cie_table
->entries
== NULL
)
1522 gdb_assert (cie_table
->num_entries
== 0);
1526 p_cie
= bsearch (&cie_pointer
, cie_table
->entries
, cie_table
->num_entries
,
1527 sizeof (cie_table
->entries
[0]), bsearch_cie_cmp
);
1533 /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1535 add_cie (struct dwarf2_cie_table
*cie_table
, struct dwarf2_cie
*cie
)
1537 const int n
= cie_table
->num_entries
;
1540 || cie_table
->entries
[n
- 1]->cie_pointer
< cie
->cie_pointer
);
1542 cie_table
->entries
=
1543 xrealloc (cie_table
->entries
, (n
+ 1) * sizeof (cie_table
->entries
[0]));
1544 cie_table
->entries
[n
] = cie
;
1545 cie_table
->num_entries
= n
+ 1;
1549 bsearch_fde_cmp (const void *key
, const void *element
)
1551 CORE_ADDR seek_pc
= *(CORE_ADDR
*) key
;
1552 struct dwarf2_fde
*fde
= *(struct dwarf2_fde
**) element
;
1553 if (seek_pc
< fde
->initial_location
)
1555 if (seek_pc
< fde
->initial_location
+ fde
->address_range
)
1560 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1561 inital location associated with it into *PC. */
1563 static struct dwarf2_fde
*
1564 dwarf2_frame_find_fde (CORE_ADDR
*pc
)
1566 struct objfile
*objfile
;
1568 ALL_OBJFILES (objfile
)
1570 struct dwarf2_fde_table
*fde_table
;
1571 struct dwarf2_fde
**p_fde
;
1575 fde_table
= objfile_data (objfile
, dwarf2_frame_objfile_data
);
1576 if (fde_table
== NULL
)
1578 dwarf2_build_frame_info (objfile
);
1579 fde_table
= objfile_data (objfile
, dwarf2_frame_objfile_data
);
1581 gdb_assert (fde_table
!= NULL
);
1583 if (fde_table
->num_entries
== 0)
1586 gdb_assert (objfile
->section_offsets
);
1587 offset
= ANOFFSET (objfile
->section_offsets
, SECT_OFF_TEXT (objfile
));
1589 gdb_assert (fde_table
->num_entries
> 0);
1590 if (*pc
< offset
+ fde_table
->entries
[0]->initial_location
)
1593 seek_pc
= *pc
- offset
;
1594 p_fde
= bsearch (&seek_pc
, fde_table
->entries
, fde_table
->num_entries
,
1595 sizeof (fde_table
->entries
[0]), bsearch_fde_cmp
);
1598 *pc
= (*p_fde
)->initial_location
+ offset
;
1605 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1607 add_fde (struct dwarf2_fde_table
*fde_table
, struct dwarf2_fde
*fde
)
1609 if (fde
->address_range
== 0)
1610 /* Discard useless FDEs. */
1613 fde_table
->num_entries
+= 1;
1614 fde_table
->entries
=
1615 xrealloc (fde_table
->entries
,
1616 fde_table
->num_entries
* sizeof (fde_table
->entries
[0]));
1617 fde_table
->entries
[fde_table
->num_entries
- 1] = fde
;
1620 #ifdef CC_HAS_LONG_LONG
1621 #define DW64_CIE_ID 0xffffffffffffffffULL
1623 #define DW64_CIE_ID ~0
1626 static gdb_byte
*decode_frame_entry (struct comp_unit
*unit
, gdb_byte
*start
,
1628 struct dwarf2_cie_table
*cie_table
,
1629 struct dwarf2_fde_table
*fde_table
);
1631 /* Decode the next CIE or FDE. Return NULL if invalid input, otherwise
1632 the next byte to be processed. */
1634 decode_frame_entry_1 (struct comp_unit
*unit
, gdb_byte
*start
, int eh_frame_p
,
1635 struct dwarf2_cie_table
*cie_table
,
1636 struct dwarf2_fde_table
*fde_table
)
1638 struct gdbarch
*gdbarch
= get_objfile_arch (unit
->objfile
);
1639 gdb_byte
*buf
, *end
;
1641 unsigned int bytes_read
;
1644 ULONGEST cie_pointer
;
1647 length
= read_initial_length (unit
->abfd
, buf
, &bytes_read
);
1651 /* Are we still within the section? */
1652 if (end
> unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
1658 /* Distinguish between 32 and 64-bit encoded frame info. */
1659 dwarf64_p
= (bytes_read
== 12);
1661 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1665 cie_id
= DW64_CIE_ID
;
1671 cie_pointer
= read_8_bytes (unit
->abfd
, buf
);
1676 cie_pointer
= read_4_bytes (unit
->abfd
, buf
);
1680 if (cie_pointer
== cie_id
)
1682 /* This is a CIE. */
1683 struct dwarf2_cie
*cie
;
1685 unsigned int cie_version
;
1687 /* Record the offset into the .debug_frame section of this CIE. */
1688 cie_pointer
= start
- unit
->dwarf_frame_buffer
;
1690 /* Check whether we've already read it. */
1691 if (find_cie (cie_table
, cie_pointer
))
1694 cie
= (struct dwarf2_cie
*)
1695 obstack_alloc (&unit
->objfile
->objfile_obstack
,
1696 sizeof (struct dwarf2_cie
));
1697 cie
->initial_instructions
= NULL
;
1698 cie
->cie_pointer
= cie_pointer
;
1700 /* The encoding for FDE's in a normal .debug_frame section
1701 depends on the target address size. */
1702 cie
->encoding
= DW_EH_PE_absptr
;
1704 /* The target address size. For .eh_frame FDEs this is considered
1705 equal to the size of a target pointer. For .dwarf_frame FDEs,
1706 this is supposed to be the target address size from the associated
1707 CU header. FIXME: We do not have a good way to determine the
1708 latter. Always use the target pointer size for now. */
1709 cie
->addr_size
= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1711 /* We'll determine the final value later, but we need to
1712 initialize it conservatively. */
1713 cie
->signal_frame
= 0;
1715 /* Check version number. */
1716 cie_version
= read_1_byte (unit
->abfd
, buf
);
1717 if (cie_version
!= 1 && cie_version
!= 3)
1719 cie
->version
= cie_version
;
1722 /* Interpret the interesting bits of the augmentation. */
1723 cie
->augmentation
= augmentation
= (char *) buf
;
1724 buf
+= (strlen (augmentation
) + 1);
1726 /* Ignore armcc augmentations. We only use them for quirks,
1727 and that doesn't happen until later. */
1728 if (strncmp (augmentation
, "armcc", 5) == 0)
1729 augmentation
+= strlen (augmentation
);
1731 /* The GCC 2.x "eh" augmentation has a pointer immediately
1732 following the augmentation string, so it must be handled
1734 if (augmentation
[0] == 'e' && augmentation
[1] == 'h')
1737 buf
+= gdbarch_ptr_bit (gdbarch
) / TARGET_CHAR_BIT
;
1741 cie
->code_alignment_factor
=
1742 read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1745 cie
->data_alignment_factor
=
1746 read_signed_leb128 (unit
->abfd
, buf
, &bytes_read
);
1749 if (cie_version
== 1)
1751 cie
->return_address_register
= read_1_byte (unit
->abfd
, buf
);
1755 cie
->return_address_register
= read_unsigned_leb128 (unit
->abfd
, buf
,
1757 cie
->return_address_register
1758 = dwarf2_frame_adjust_regnum (gdbarch
,
1759 cie
->return_address_register
,
1764 cie
->saw_z_augmentation
= (*augmentation
== 'z');
1765 if (cie
->saw_z_augmentation
)
1769 length
= read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1773 cie
->initial_instructions
= buf
+ length
;
1777 while (*augmentation
)
1779 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1780 if (*augmentation
== 'L')
1787 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1788 else if (*augmentation
== 'R')
1790 cie
->encoding
= *buf
++;
1794 /* "P" indicates a personality routine in the CIE augmentation. */
1795 else if (*augmentation
== 'P')
1797 /* Skip. Avoid indirection since we throw away the result. */
1798 gdb_byte encoding
= (*buf
++) & ~DW_EH_PE_indirect
;
1799 read_encoded_value (unit
, encoding
, cie
->addr_size
,
1800 buf
, &bytes_read
, 0);
1805 /* "S" indicates a signal frame, such that the return
1806 address must not be decremented to locate the call frame
1807 info for the previous frame; it might even be the first
1808 instruction of a function, so decrementing it would take
1809 us to a different function. */
1810 else if (*augmentation
== 'S')
1812 cie
->signal_frame
= 1;
1816 /* Otherwise we have an unknown augmentation. Assume that either
1817 there is no augmentation data, or we saw a 'z' prefix. */
1820 if (cie
->initial_instructions
)
1821 buf
= cie
->initial_instructions
;
1826 cie
->initial_instructions
= buf
;
1830 add_cie (cie_table
, cie
);
1834 /* This is a FDE. */
1835 struct dwarf2_fde
*fde
;
1837 /* In an .eh_frame section, the CIE pointer is the delta between the
1838 address within the FDE where the CIE pointer is stored and the
1839 address of the CIE. Convert it to an offset into the .eh_frame
1843 cie_pointer
= buf
- unit
->dwarf_frame_buffer
- cie_pointer
;
1844 cie_pointer
-= (dwarf64_p
? 8 : 4);
1847 /* In either case, validate the result is still within the section. */
1848 if (cie_pointer
>= unit
->dwarf_frame_size
)
1851 fde
= (struct dwarf2_fde
*)
1852 obstack_alloc (&unit
->objfile
->objfile_obstack
,
1853 sizeof (struct dwarf2_fde
));
1854 fde
->cie
= find_cie (cie_table
, cie_pointer
);
1855 if (fde
->cie
== NULL
)
1857 decode_frame_entry (unit
, unit
->dwarf_frame_buffer
+ cie_pointer
,
1858 eh_frame_p
, cie_table
, fde_table
);
1859 fde
->cie
= find_cie (cie_table
, cie_pointer
);
1862 gdb_assert (fde
->cie
!= NULL
);
1864 fde
->initial_location
=
1865 read_encoded_value (unit
, fde
->cie
->encoding
, fde
->cie
->addr_size
,
1866 buf
, &bytes_read
, 0);
1869 fde
->address_range
=
1870 read_encoded_value (unit
, fde
->cie
->encoding
& 0x0f,
1871 fde
->cie
->addr_size
, buf
, &bytes_read
, 0);
1874 /* A 'z' augmentation in the CIE implies the presence of an
1875 augmentation field in the FDE as well. The only thing known
1876 to be in here at present is the LSDA entry for EH. So we
1877 can skip the whole thing. */
1878 if (fde
->cie
->saw_z_augmentation
)
1882 length
= read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1883 buf
+= bytes_read
+ length
;
1888 fde
->instructions
= buf
;
1891 fde
->eh_frame_p
= eh_frame_p
;
1893 add_fde (fde_table
, fde
);
1899 /* Read a CIE or FDE in BUF and decode it. */
1901 decode_frame_entry (struct comp_unit
*unit
, gdb_byte
*start
, int eh_frame_p
,
1902 struct dwarf2_cie_table
*cie_table
,
1903 struct dwarf2_fde_table
*fde_table
)
1905 enum { NONE
, ALIGN4
, ALIGN8
, FAIL
} workaround
= NONE
;
1908 ptrdiff_t start_offset
;
1912 ret
= decode_frame_entry_1 (unit
, start
, eh_frame_p
,
1913 cie_table
, fde_table
);
1917 /* We have corrupt input data of some form. */
1919 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
1920 and mismatches wrt padding and alignment of debug sections. */
1921 /* Note that there is no requirement in the standard for any
1922 alignment at all in the frame unwind sections. Testing for
1923 alignment before trying to interpret data would be incorrect.
1925 However, GCC traditionally arranged for frame sections to be
1926 sized such that the FDE length and CIE fields happen to be
1927 aligned (in theory, for performance). This, unfortunately,
1928 was done with .align directives, which had the side effect of
1929 forcing the section to be aligned by the linker.
1931 This becomes a problem when you have some other producer that
1932 creates frame sections that are not as strictly aligned. That
1933 produces a hole in the frame info that gets filled by the
1936 The GCC behaviour is arguably a bug, but it's effectively now
1937 part of the ABI, so we're now stuck with it, at least at the
1938 object file level. A smart linker may decide, in the process
1939 of compressing duplicate CIE information, that it can rewrite
1940 the entire output section without this extra padding. */
1942 start_offset
= start
- unit
->dwarf_frame_buffer
;
1943 if (workaround
< ALIGN4
&& (start_offset
& 3) != 0)
1945 start
+= 4 - (start_offset
& 3);
1946 workaround
= ALIGN4
;
1949 if (workaround
< ALIGN8
&& (start_offset
& 7) != 0)
1951 start
+= 8 - (start_offset
& 7);
1952 workaround
= ALIGN8
;
1956 /* Nothing left to try. Arrange to return as if we've consumed
1957 the entire input section. Hopefully we'll get valid info from
1958 the other of .debug_frame/.eh_frame. */
1960 ret
= unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
;
1970 complaint (&symfile_complaints
,
1971 _("Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
1972 unit
->dwarf_frame_section
->owner
->filename
,
1973 unit
->dwarf_frame_section
->name
);
1977 complaint (&symfile_complaints
,
1978 _("Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
1979 unit
->dwarf_frame_section
->owner
->filename
,
1980 unit
->dwarf_frame_section
->name
);
1984 complaint (&symfile_complaints
,
1985 _("Corrupt data in %s:%s"),
1986 unit
->dwarf_frame_section
->owner
->filename
,
1987 unit
->dwarf_frame_section
->name
);
1995 /* Imported from dwarf2read.c. */
1996 extern void dwarf2_get_section_info (struct objfile
*, const char *, asection
**,
1997 gdb_byte
**, bfd_size_type
*);
2000 qsort_fde_cmp (const void *a
, const void *b
)
2002 struct dwarf2_fde
*aa
= *(struct dwarf2_fde
**)a
;
2003 struct dwarf2_fde
*bb
= *(struct dwarf2_fde
**)b
;
2005 if (aa
->initial_location
== bb
->initial_location
)
2007 if (aa
->address_range
!= bb
->address_range
2008 && aa
->eh_frame_p
== 0 && bb
->eh_frame_p
== 0)
2009 /* Linker bug, e.g. gold/10400.
2010 Work around it by keeping stable sort order. */
2011 return (a
< b
) ? -1 : 1;
2013 /* Put eh_frame entries after debug_frame ones. */
2014 return aa
->eh_frame_p
- bb
->eh_frame_p
;
2017 return (aa
->initial_location
< bb
->initial_location
) ? -1 : 1;
2021 dwarf2_build_frame_info (struct objfile
*objfile
)
2023 struct comp_unit
*unit
;
2024 gdb_byte
*frame_ptr
;
2025 struct dwarf2_cie_table cie_table
;
2026 struct dwarf2_fde_table fde_table
;
2027 struct dwarf2_fde_table
*fde_table2
;
2029 cie_table
.num_entries
= 0;
2030 cie_table
.entries
= NULL
;
2032 fde_table
.num_entries
= 0;
2033 fde_table
.entries
= NULL
;
2035 /* Build a minimal decoding of the DWARF2 compilation unit. */
2036 unit
= (struct comp_unit
*) obstack_alloc (&objfile
->objfile_obstack
,
2037 sizeof (struct comp_unit
));
2038 unit
->abfd
= objfile
->obfd
;
2039 unit
->objfile
= objfile
;
2043 dwarf2_get_section_info (objfile
, ".eh_frame",
2044 &unit
->dwarf_frame_section
,
2045 &unit
->dwarf_frame_buffer
,
2046 &unit
->dwarf_frame_size
);
2047 if (unit
->dwarf_frame_size
)
2049 asection
*got
, *txt
;
2051 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2052 that is used for the i386/amd64 target, which currently is
2053 the only target in GCC that supports/uses the
2054 DW_EH_PE_datarel encoding. */
2055 got
= bfd_get_section_by_name (unit
->abfd
, ".got");
2057 unit
->dbase
= got
->vma
;
2059 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2061 txt
= bfd_get_section_by_name (unit
->abfd
, ".text");
2063 unit
->tbase
= txt
->vma
;
2065 frame_ptr
= unit
->dwarf_frame_buffer
;
2066 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2067 frame_ptr
= decode_frame_entry (unit
, frame_ptr
, 1,
2068 &cie_table
, &fde_table
);
2070 if (cie_table
.num_entries
!= 0)
2072 /* Reinit cie_table: debug_frame has different CIEs. */
2073 xfree (cie_table
.entries
);
2074 cie_table
.num_entries
= 0;
2075 cie_table
.entries
= NULL
;
2079 dwarf2_get_section_info (objfile
, ".debug_frame",
2080 &unit
->dwarf_frame_section
,
2081 &unit
->dwarf_frame_buffer
,
2082 &unit
->dwarf_frame_size
);
2083 if (unit
->dwarf_frame_size
)
2085 frame_ptr
= unit
->dwarf_frame_buffer
;
2086 while (frame_ptr
< unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
2087 frame_ptr
= decode_frame_entry (unit
, frame_ptr
, 0,
2088 &cie_table
, &fde_table
);
2091 /* Discard the cie_table, it is no longer needed. */
2092 if (cie_table
.num_entries
!= 0)
2094 xfree (cie_table
.entries
);
2095 cie_table
.entries
= NULL
; /* Paranoia. */
2096 cie_table
.num_entries
= 0; /* Paranoia. */
2099 /* Copy fde_table to obstack: it is needed at runtime. */
2100 fde_table2
= (struct dwarf2_fde_table
*)
2101 obstack_alloc (&objfile
->objfile_obstack
, sizeof (*fde_table2
));
2103 if (fde_table
.num_entries
== 0)
2105 fde_table2
->entries
= NULL
;
2106 fde_table2
->num_entries
= 0;
2110 struct dwarf2_fde
*fde_prev
= NULL
;
2111 struct dwarf2_fde
*first_non_zero_fde
= NULL
;
2114 /* Prepare FDE table for lookups. */
2115 qsort (fde_table
.entries
, fde_table
.num_entries
,
2116 sizeof (fde_table
.entries
[0]), qsort_fde_cmp
);
2118 /* Check for leftovers from --gc-sections. The GNU linker sets
2119 the relevant symbols to zero, but doesn't zero the FDE *end*
2120 ranges because there's no relocation there. It's (offset,
2121 length), not (start, end). On targets where address zero is
2122 just another valid address this can be a problem, since the
2123 FDEs appear to be non-empty in the output --- we could pick
2124 out the wrong FDE. To work around this, when overlaps are
2125 detected, we prefer FDEs that do not start at zero.
2127 Start by finding the first FDE with non-zero start. Below
2128 we'll discard all FDEs that start at zero and overlap this
2130 for (i
= 0; i
< fde_table
.num_entries
; i
++)
2132 struct dwarf2_fde
*fde
= fde_table
.entries
[i
];
2134 if (fde
->initial_location
!= 0)
2136 first_non_zero_fde
= fde
;
2141 /* Since we'll be doing bsearch, squeeze out identical (except
2142 for eh_frame_p) fde entries so bsearch result is predictable.
2143 Also discard leftovers from --gc-sections. */
2144 fde_table2
->num_entries
= 0;
2145 for (i
= 0; i
< fde_table
.num_entries
; i
++)
2147 struct dwarf2_fde
*fde
= fde_table
.entries
[i
];
2149 if (fde
->initial_location
== 0
2150 && first_non_zero_fde
!= NULL
2151 && (first_non_zero_fde
->initial_location
2152 < fde
->initial_location
+ fde
->address_range
))
2155 if (fde_prev
!= NULL
2156 && fde_prev
->initial_location
== fde
->initial_location
)
2159 obstack_grow (&objfile
->objfile_obstack
, &fde_table
.entries
[i
],
2160 sizeof (fde_table
.entries
[0]));
2161 ++fde_table2
->num_entries
;
2164 fde_table2
->entries
= obstack_finish (&objfile
->objfile_obstack
);
2166 /* Discard the original fde_table. */
2167 xfree (fde_table
.entries
);
2170 set_objfile_data (objfile
, dwarf2_frame_objfile_data
, fde_table2
);
2173 /* Provide a prototype to silence -Wmissing-prototypes. */
2174 void _initialize_dwarf2_frame (void);
2177 _initialize_dwarf2_frame (void)
2179 dwarf2_frame_data
= gdbarch_data_register_pre_init (dwarf2_frame_init
);
2180 dwarf2_frame_objfile_data
= register_objfile_data ();