1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright 2003, 2004 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 2 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, write to the Free Software
21 Foundation, Inc., 59 Temple Place - Suite 330,
22 Boston, MA 02111-1307, USA. */
25 #include "dwarf2expr.h"
26 #include "elf/dwarf2.h"
28 #include "frame-base.h"
29 #include "frame-unwind.h"
36 #include "gdb_assert.h"
37 #include "gdb_string.h"
39 #include "complaints.h"
40 #include "dwarf2-frame.h"
42 /* Call Frame Information (CFI). */
44 /* Common Information Entry (CIE). */
48 /* Offset into the .debug_frame section where this CIE was found.
49 Used to identify this CIE. */
52 /* Constant that is factored out of all advance location
54 ULONGEST code_alignment_factor
;
56 /* Constants that is factored out of all offset instructions. */
57 LONGEST data_alignment_factor
;
59 /* Return address column. */
60 ULONGEST return_address_register
;
62 /* Instruction sequence to initialize a register set. */
63 unsigned char *initial_instructions
;
66 /* Encoding of addresses. */
67 unsigned char encoding
;
69 /* True if a 'z' augmentation existed. */
70 unsigned char saw_z_augmentation
;
72 struct dwarf2_cie
*next
;
75 /* Frame Description Entry (FDE). */
79 /* CIE for this FDE. */
80 struct dwarf2_cie
*cie
;
82 /* First location associated with this FDE. */
83 CORE_ADDR initial_location
;
85 /* Number of bytes of program instructions described by this FDE. */
86 CORE_ADDR address_range
;
88 /* Instruction sequence. */
89 unsigned char *instructions
;
92 struct dwarf2_fde
*next
;
95 static struct dwarf2_fde
*dwarf2_frame_find_fde (CORE_ADDR
*pc
);
98 /* Structure describing a frame state. */
100 struct dwarf2_frame_state
102 /* Each register save state can be described in terms of a CFA slot,
103 another register, or a location expression. */
104 struct dwarf2_frame_state_reg_info
106 struct dwarf2_frame_state_reg
*reg
;
109 /* Used to implement DW_CFA_remember_state. */
110 struct dwarf2_frame_state_reg_info
*prev
;
115 unsigned char *cfa_exp
;
122 /* The PC described by the current frame state. */
125 /* Initial register set from the CIE.
126 Used to implement DW_CFA_restore. */
127 struct dwarf2_frame_state_reg_info initial
;
129 /* The information we care about from the CIE. */
132 ULONGEST retaddr_column
;
135 /* Store the length the expression for the CFA in the `cfa_reg' field,
136 which is unused in that case. */
137 #define cfa_exp_len cfa_reg
139 /* Assert that the register set RS is large enough to store NUM_REGS
140 columns. If necessary, enlarge the register set. */
143 dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info
*rs
,
146 size_t size
= sizeof (struct dwarf2_frame_state_reg
);
148 if (num_regs
<= rs
->num_regs
)
151 rs
->reg
= (struct dwarf2_frame_state_reg
*)
152 xrealloc (rs
->reg
, num_regs
* size
);
154 /* Initialize newly allocated registers. */
155 memset (rs
->reg
+ rs
->num_regs
, 0, (num_regs
- rs
->num_regs
) * size
);
156 rs
->num_regs
= num_regs
;
159 /* Copy the register columns in register set RS into newly allocated
160 memory and return a pointer to this newly created copy. */
162 static struct dwarf2_frame_state_reg
*
163 dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info
*rs
)
165 size_t size
= rs
->num_regs
* sizeof (struct dwarf2_frame_state_reg
);
166 struct dwarf2_frame_state_reg
*reg
;
168 reg
= (struct dwarf2_frame_state_reg
*) xmalloc (size
);
169 memcpy (reg
, rs
->reg
, size
);
174 /* Release the memory allocated to register set RS. */
177 dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info
*rs
)
181 dwarf2_frame_state_free_regs (rs
->prev
);
188 /* Release the memory allocated to the frame state FS. */
191 dwarf2_frame_state_free (void *p
)
193 struct dwarf2_frame_state
*fs
= p
;
195 dwarf2_frame_state_free_regs (fs
->initial
.prev
);
196 dwarf2_frame_state_free_regs (fs
->regs
.prev
);
197 xfree (fs
->initial
.reg
);
198 xfree (fs
->regs
.reg
);
203 /* Helper functions for execute_stack_op. */
206 read_reg (void *baton
, int reg
)
208 struct frame_info
*next_frame
= (struct frame_info
*) baton
;
209 struct gdbarch
*gdbarch
= get_frame_arch (next_frame
);
213 regnum
= DWARF2_REG_TO_REGNUM (reg
);
215 buf
= (char *) alloca (register_size (gdbarch
, regnum
));
216 frame_unwind_register (next_frame
, regnum
, buf
);
217 return extract_typed_address (buf
, builtin_type_void_data_ptr
);
221 read_mem (void *baton
, char *buf
, CORE_ADDR addr
, size_t len
)
223 read_memory (addr
, buf
, len
);
227 no_get_frame_base (void *baton
, unsigned char **start
, size_t *length
)
229 internal_error (__FILE__
, __LINE__
,
230 "Support for DW_OP_fbreg is unimplemented");
234 no_get_tls_address (void *baton
, CORE_ADDR offset
)
236 internal_error (__FILE__
, __LINE__
,
237 "Support for DW_OP_GNU_push_tls_address is unimplemented");
241 execute_stack_op (unsigned char *exp
, ULONGEST len
,
242 struct frame_info
*next_frame
, CORE_ADDR initial
)
244 struct dwarf_expr_context
*ctx
;
247 ctx
= new_dwarf_expr_context ();
248 ctx
->baton
= next_frame
;
249 ctx
->read_reg
= read_reg
;
250 ctx
->read_mem
= read_mem
;
251 ctx
->get_frame_base
= no_get_frame_base
;
252 ctx
->get_tls_address
= no_get_tls_address
;
254 dwarf_expr_push (ctx
, initial
);
255 dwarf_expr_eval (ctx
, exp
, len
);
256 result
= dwarf_expr_fetch (ctx
, 0);
259 result
= read_reg (next_frame
, result
);
261 free_dwarf_expr_context (ctx
);
268 execute_cfa_program (unsigned char *insn_ptr
, unsigned char *insn_end
,
269 struct frame_info
*next_frame
,
270 struct dwarf2_frame_state
*fs
)
272 CORE_ADDR pc
= frame_pc_unwind (next_frame
);
275 while (insn_ptr
< insn_end
&& fs
->pc
<= pc
)
277 unsigned char insn
= *insn_ptr
++;
281 if ((insn
& 0xc0) == DW_CFA_advance_loc
)
282 fs
->pc
+= (insn
& 0x3f) * fs
->code_align
;
283 else if ((insn
& 0xc0) == DW_CFA_offset
)
286 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
287 offset
= utmp
* fs
->data_align
;
288 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
289 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
290 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
292 else if ((insn
& 0xc0) == DW_CFA_restore
)
294 gdb_assert (fs
->initial
.reg
);
296 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
297 fs
->regs
.reg
[reg
] = fs
->initial
.reg
[reg
];
304 fs
->pc
= dwarf2_read_address (insn_ptr
, insn_end
, &bytes_read
);
305 insn_ptr
+= bytes_read
;
308 case DW_CFA_advance_loc1
:
309 utmp
= extract_unsigned_integer (insn_ptr
, 1);
310 fs
->pc
+= utmp
* fs
->code_align
;
313 case DW_CFA_advance_loc2
:
314 utmp
= extract_unsigned_integer (insn_ptr
, 2);
315 fs
->pc
+= utmp
* fs
->code_align
;
318 case DW_CFA_advance_loc4
:
319 utmp
= extract_unsigned_integer (insn_ptr
, 4);
320 fs
->pc
+= utmp
* fs
->code_align
;
324 case DW_CFA_offset_extended
:
325 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
326 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
327 offset
= utmp
* fs
->data_align
;
328 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
329 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
330 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
333 case DW_CFA_restore_extended
:
334 gdb_assert (fs
->initial
.reg
);
335 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
336 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
337 fs
->regs
.reg
[reg
] = fs
->initial
.reg
[reg
];
340 case DW_CFA_undefined
:
341 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
342 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
343 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_UNDEFINED
;
346 case DW_CFA_same_value
:
347 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
348 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
349 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAME_VALUE
;
352 case DW_CFA_register
:
353 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
354 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
355 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
356 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_REG
;
357 fs
->regs
.reg
[reg
].loc
.reg
= utmp
;
360 case DW_CFA_remember_state
:
362 struct dwarf2_frame_state_reg_info
*new_rs
;
364 new_rs
= XMALLOC (struct dwarf2_frame_state_reg_info
);
366 fs
->regs
.reg
= dwarf2_frame_state_copy_regs (&fs
->regs
);
367 fs
->regs
.prev
= new_rs
;
371 case DW_CFA_restore_state
:
373 struct dwarf2_frame_state_reg_info
*old_rs
= fs
->regs
.prev
;
377 complaint (&symfile_complaints
, "\
378 bad CFI data; mismatched DW_CFA_restore_state at 0x%s", paddr (fs
->pc
));
382 xfree (fs
->regs
.reg
);
390 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &fs
->cfa_reg
);
391 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
392 fs
->cfa_offset
= utmp
;
393 fs
->cfa_how
= CFA_REG_OFFSET
;
396 case DW_CFA_def_cfa_register
:
397 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &fs
->cfa_reg
);
398 fs
->cfa_how
= CFA_REG_OFFSET
;
401 case DW_CFA_def_cfa_offset
:
402 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &fs
->cfa_offset
);
403 /* cfa_how deliberately not set. */
409 case DW_CFA_def_cfa_expression
:
410 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &fs
->cfa_exp_len
);
411 fs
->cfa_exp
= insn_ptr
;
412 fs
->cfa_how
= CFA_EXP
;
413 insn_ptr
+= fs
->cfa_exp_len
;
416 case DW_CFA_expression
:
417 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
418 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
419 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
420 fs
->regs
.reg
[reg
].loc
.exp
= insn_ptr
;
421 fs
->regs
.reg
[reg
].exp_len
= utmp
;
422 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_EXP
;
426 case DW_CFA_offset_extended_sf
:
427 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, ®
);
428 insn_ptr
= read_sleb128 (insn_ptr
, insn_end
, &offset
);
429 offset
*= fs
->data_align
;
430 dwarf2_frame_state_alloc_regs (&fs
->regs
, reg
+ 1);
431 fs
->regs
.reg
[reg
].how
= DWARF2_FRAME_REG_SAVED_OFFSET
;
432 fs
->regs
.reg
[reg
].loc
.offset
= offset
;
435 case DW_CFA_def_cfa_sf
:
436 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &fs
->cfa_reg
);
437 insn_ptr
= read_sleb128 (insn_ptr
, insn_end
, &offset
);
438 fs
->cfa_offset
= offset
* fs
->data_align
;
439 fs
->cfa_how
= CFA_REG_OFFSET
;
442 case DW_CFA_def_cfa_offset_sf
:
443 insn_ptr
= read_sleb128 (insn_ptr
, insn_end
, &offset
);
444 fs
->cfa_offset
= offset
* fs
->data_align
;
445 /* cfa_how deliberately not set. */
448 case DW_CFA_GNU_args_size
:
450 insn_ptr
= read_uleb128 (insn_ptr
, insn_end
, &utmp
);
454 internal_error (__FILE__
, __LINE__
, "Unknown CFI encountered.");
459 /* Don't allow remember/restore between CIE and FDE programs. */
460 dwarf2_frame_state_free_regs (fs
->regs
.prev
);
461 fs
->regs
.prev
= NULL
;
465 /* Architecture-specific operations. */
467 /* Per-architecture data key. */
468 static struct gdbarch_data
*dwarf2_frame_data
;
470 struct dwarf2_frame_ops
472 /* Pre-initialize the register state REG for register REGNUM. */
473 void (*init_reg
) (struct gdbarch
*, int, struct dwarf2_frame_state_reg
*);
475 /* Check whether the frame preceding NEXT_FRAME will be a signal
477 int (*signal_frame_p
) (struct gdbarch
*, struct frame_info
*);
480 /* Default architecture-specific register state initialization
484 dwarf2_frame_default_init_reg (struct gdbarch
*gdbarch
, int regnum
,
485 struct dwarf2_frame_state_reg
*reg
)
487 /* If we have a register that acts as a program counter, mark it as
488 a destination for the return address. If we have a register that
489 serves as the stack pointer, arrange for it to be filled with the
490 call frame address (CFA). The other registers are marked as
493 We copy the return address to the program counter, since many
494 parts in GDB assume that it is possible to get the return address
495 by unwinding the program counter register. However, on ISA's
496 with a dedicated return address register, the CFI usually only
497 contains information to unwind that return address register.
499 The reason we're treating the stack pointer special here is
500 because in many cases GCC doesn't emit CFI for the stack pointer
501 and implicitly assumes that it is equal to the CFA. This makes
502 some sense since the DWARF specification (version 3, draft 8,
505 "Typically, the CFA is defined to be the value of the stack
506 pointer at the call site in the previous frame (which may be
507 different from its value on entry to the current frame)."
509 However, this isn't true for all platforms supported by GCC
510 (e.g. IBM S/390 and zSeries). Those architectures should provide
511 their own architecture-specific initialization function. */
513 if (regnum
== PC_REGNUM
)
514 reg
->how
= DWARF2_FRAME_REG_RA
;
515 else if (regnum
== SP_REGNUM
)
516 reg
->how
= DWARF2_FRAME_REG_CFA
;
519 /* Return a default for the architecture-specific operations. */
522 dwarf2_frame_init (struct obstack
*obstack
)
524 struct dwarf2_frame_ops
*ops
;
526 ops
= OBSTACK_ZALLOC (obstack
, struct dwarf2_frame_ops
);
527 ops
->init_reg
= dwarf2_frame_default_init_reg
;
531 /* Set the architecture-specific register state initialization
532 function for GDBARCH to INIT_REG. */
535 dwarf2_frame_set_init_reg (struct gdbarch
*gdbarch
,
536 void (*init_reg
) (struct gdbarch
*, int,
537 struct dwarf2_frame_state_reg
*))
539 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
541 ops
->init_reg
= init_reg
;
544 /* Pre-initialize the register state REG for register REGNUM. */
547 dwarf2_frame_init_reg (struct gdbarch
*gdbarch
, int regnum
,
548 struct dwarf2_frame_state_reg
*reg
)
550 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
552 ops
->init_reg (gdbarch
, regnum
, reg
);
555 /* Set the architecture-specific signal trampoline recognition
556 function for GDBARCH to SIGNAL_FRAME_P. */
559 dwarf2_frame_set_signal_frame_p (struct gdbarch
*gdbarch
,
560 int (*signal_frame_p
) (struct gdbarch
*,
561 struct frame_info
*))
563 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
565 ops
->signal_frame_p
= signal_frame_p
;
568 /* Query the architecture-specific signal frame recognizer for
572 dwarf2_frame_signal_frame_p (struct gdbarch
*gdbarch
,
573 struct frame_info
*next_frame
)
575 struct dwarf2_frame_ops
*ops
= gdbarch_data (gdbarch
, dwarf2_frame_data
);
577 if (ops
->signal_frame_p
== NULL
)
579 return ops
->signal_frame_p (gdbarch
, next_frame
);
583 struct dwarf2_frame_cache
585 /* DWARF Call Frame Address. */
588 /* Saved registers, indexed by GDB register number, not by DWARF
590 struct dwarf2_frame_state_reg
*reg
;
593 static struct dwarf2_frame_cache
*
594 dwarf2_frame_cache (struct frame_info
*next_frame
, void **this_cache
)
596 struct cleanup
*old_chain
;
597 struct gdbarch
*gdbarch
= get_frame_arch (next_frame
);
598 const int num_regs
= NUM_REGS
+ NUM_PSEUDO_REGS
;
599 struct dwarf2_frame_cache
*cache
;
600 struct dwarf2_frame_state
*fs
;
601 struct dwarf2_fde
*fde
;
606 /* Allocate a new cache. */
607 cache
= FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache
);
608 cache
->reg
= FRAME_OBSTACK_CALLOC (num_regs
, struct dwarf2_frame_state_reg
);
610 /* Allocate and initialize the frame state. */
611 fs
= XMALLOC (struct dwarf2_frame_state
);
612 memset (fs
, 0, sizeof (struct dwarf2_frame_state
));
613 old_chain
= make_cleanup (dwarf2_frame_state_free
, fs
);
617 Note that if NEXT_FRAME is never supposed to return (i.e. a call
618 to abort), the compiler might optimize away the instruction at
619 NEXT_FRAME's return address. As a result the return address will
620 point at some random instruction, and the CFI for that
621 instruction is probably worthless to us. GCC's unwinder solves
622 this problem by substracting 1 from the return address to get an
623 address in the middle of a presumed call instruction (or the
624 instruction in the associated delay slot). This should only be
625 done for "normal" frames and not for resume-type frames (signal
626 handlers, sentinel frames, dummy frames). The function
627 frame_unwind_address_in_block does just this. It's not clear how
628 reliable the method is though; there is the potential for the
629 register state pre-call being different to that on return. */
630 fs
->pc
= frame_unwind_address_in_block (next_frame
);
632 /* Find the correct FDE. */
633 fde
= dwarf2_frame_find_fde (&fs
->pc
);
634 gdb_assert (fde
!= NULL
);
636 /* Extract any interesting information from the CIE. */
637 fs
->data_align
= fde
->cie
->data_alignment_factor
;
638 fs
->code_align
= fde
->cie
->code_alignment_factor
;
639 fs
->retaddr_column
= fde
->cie
->return_address_register
;
641 /* First decode all the insns in the CIE. */
642 execute_cfa_program (fde
->cie
->initial_instructions
,
643 fde
->cie
->end
, next_frame
, fs
);
645 /* Save the initialized register set. */
646 fs
->initial
= fs
->regs
;
647 fs
->initial
.reg
= dwarf2_frame_state_copy_regs (&fs
->regs
);
649 /* Then decode the insns in the FDE up to our target PC. */
650 execute_cfa_program (fde
->instructions
, fde
->end
, next_frame
, fs
);
652 /* Caclulate the CFA. */
656 cache
->cfa
= read_reg (next_frame
, fs
->cfa_reg
);
657 cache
->cfa
+= fs
->cfa_offset
;
662 execute_stack_op (fs
->cfa_exp
, fs
->cfa_exp_len
, next_frame
, 0);
666 internal_error (__FILE__
, __LINE__
, "Unknown CFA rule.");
669 /* Initialize the register state. */
673 for (regnum
= 0; regnum
< num_regs
; regnum
++)
674 dwarf2_frame_init_reg (gdbarch
, regnum
, &cache
->reg
[regnum
]);
677 /* Go through the DWARF2 CFI generated table and save its register
678 location information in the cache. Note that we don't skip the
679 return address column; it's perfectly all right for it to
680 correspond to a real register. If it doesn't correspond to a
681 real register, or if we shouldn't treat it as such,
682 DWARF2_REG_TO_REGNUM should be defined to return a number outside
683 the range [0, NUM_REGS). */
685 int column
; /* CFI speak for "register number". */
687 for (column
= 0; column
< fs
->regs
.num_regs
; column
++)
689 /* Use the GDB register number as the destination index. */
690 int regnum
= DWARF2_REG_TO_REGNUM (column
);
692 /* If there's no corresponding GDB register, ignore it. */
693 if (regnum
< 0 || regnum
>= num_regs
)
696 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
697 of all debug info registers. If it doesn't, complain (but
698 not too loudly). It turns out that GCC assumes that an
699 unspecified register implies "same value" when CFI (draft
700 7) specifies nothing at all. Such a register could equally
701 be interpreted as "undefined". Also note that this check
702 isn't sufficient; it only checks that all registers in the
703 range [0 .. max column] are specified, and won't detect
704 problems when a debug info register falls outside of the
705 table. We need a way of iterating through all the valid
706 DWARF2 register numbers. */
707 if (fs
->regs
.reg
[column
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
709 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
710 complaint (&symfile_complaints
, "\
711 incomplete CFI data; unspecified registers (e.g., %s) at 0x%s",
712 gdbarch_register_name (gdbarch
, regnum
),
716 cache
->reg
[regnum
] = fs
->regs
.reg
[column
];
720 /* Eliminate any DWARF2_FRAME_REG_RA rules. */
724 for (regnum
= 0; regnum
< num_regs
; regnum
++)
726 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
728 struct dwarf2_frame_state_reg
*retaddr_reg
=
729 &fs
->regs
.reg
[fs
->retaddr_column
];
731 /* It seems rather bizarre to specify an "empty" column as
732 the return adress column. However, this is exactly
733 what GCC does on some targets. It turns out that GCC
734 assumes that the return address can be found in the
735 register corresponding to the return address column.
736 Incidentally, that's how should treat a return address
737 column specifying "same value" too. */
738 if (fs
->retaddr_column
< fs
->regs
.num_regs
739 && retaddr_reg
->how
!= DWARF2_FRAME_REG_UNSPECIFIED
740 && retaddr_reg
->how
!= DWARF2_FRAME_REG_SAME_VALUE
)
741 cache
->reg
[regnum
] = *retaddr_reg
;
744 cache
->reg
[regnum
].loc
.reg
= fs
->retaddr_column
;
745 cache
->reg
[regnum
].how
= DWARF2_FRAME_REG_SAVED_REG
;
751 do_cleanups (old_chain
);
758 dwarf2_frame_this_id (struct frame_info
*next_frame
, void **this_cache
,
759 struct frame_id
*this_id
)
761 struct dwarf2_frame_cache
*cache
=
762 dwarf2_frame_cache (next_frame
, this_cache
);
764 (*this_id
) = frame_id_build (cache
->cfa
, frame_func_unwind (next_frame
));
768 dwarf2_frame_prev_register (struct frame_info
*next_frame
, void **this_cache
,
769 int regnum
, int *optimizedp
,
770 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
771 int *realnump
, void *valuep
)
773 struct gdbarch
*gdbarch
= get_frame_arch (next_frame
);
774 struct dwarf2_frame_cache
*cache
=
775 dwarf2_frame_cache (next_frame
, this_cache
);
777 switch (cache
->reg
[regnum
].how
)
779 case DWARF2_FRAME_REG_UNDEFINED
:
780 /* If CFI explicitly specified that the value isn't defined,
781 mark it as optimized away; the value isn't available. */
788 /* In some cases, for example %eflags on the i386, we have
789 to provide a sane value, even though this register wasn't
790 saved. Assume we can get it from NEXT_FRAME. */
791 frame_unwind_register (next_frame
, regnum
, valuep
);
795 case DWARF2_FRAME_REG_SAVED_OFFSET
:
797 *lvalp
= lval_memory
;
798 *addrp
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
802 /* Read the value in from memory. */
803 read_memory (*addrp
, valuep
, register_size (gdbarch
, regnum
));
807 case DWARF2_FRAME_REG_SAVED_REG
:
809 *lvalp
= lval_register
;
811 *realnump
= DWARF2_REG_TO_REGNUM (cache
->reg
[regnum
].loc
.reg
);
813 frame_unwind_register (next_frame
, (*realnump
), valuep
);
816 case DWARF2_FRAME_REG_SAVED_EXP
:
818 *lvalp
= lval_memory
;
819 *addrp
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
,
820 cache
->reg
[regnum
].exp_len
,
821 next_frame
, cache
->cfa
);
825 /* Read the value in from memory. */
826 read_memory (*addrp
, valuep
, register_size (gdbarch
, regnum
));
830 case DWARF2_FRAME_REG_UNSPECIFIED
:
831 /* GCC, in its infinite wisdom decided to not provide unwind
832 information for registers that are "same value". Since
833 DWARF2 (3 draft 7) doesn't define such behavior, said
834 registers are actually undefined (which is different to CFI
835 "undefined"). Code above issues a complaint about this.
836 Here just fudge the books, assume GCC, and that the value is
837 more inner on the stack. */
839 *lvalp
= lval_register
;
843 frame_unwind_register (next_frame
, (*realnump
), valuep
);
846 case DWARF2_FRAME_REG_SAME_VALUE
:
848 *lvalp
= lval_register
;
852 frame_unwind_register (next_frame
, (*realnump
), valuep
);
855 case DWARF2_FRAME_REG_CFA
:
862 /* Store the value. */
863 store_typed_address (valuep
, builtin_type_void_data_ptr
, cache
->cfa
);
868 internal_error (__FILE__
, __LINE__
, "Unknown register rule.");
872 static const struct frame_unwind dwarf2_frame_unwind
=
875 dwarf2_frame_this_id
,
876 dwarf2_frame_prev_register
879 static const struct frame_unwind dwarf2_signal_frame_unwind
=
882 dwarf2_frame_this_id
,
883 dwarf2_frame_prev_register
886 const struct frame_unwind
*
887 dwarf2_frame_sniffer (struct frame_info
*next_frame
)
889 /* Grab an address that is guarenteed to reside somewhere within the
890 function. frame_pc_unwind(), for a no-return next function, can
891 end up returning something past the end of this function's body. */
892 CORE_ADDR block_addr
= frame_unwind_address_in_block (next_frame
);
893 if (!dwarf2_frame_find_fde (&block_addr
))
896 /* On some targets, signal trampolines may have unwind information.
897 We need to recognize them so that we set the frame type
900 if (dwarf2_frame_signal_frame_p (get_frame_arch (next_frame
),
902 return &dwarf2_signal_frame_unwind
;
904 return &dwarf2_frame_unwind
;
908 /* There is no explicitly defined relationship between the CFA and the
909 location of frame's local variables and arguments/parameters.
910 Therefore, frame base methods on this page should probably only be
911 used as a last resort, just to avoid printing total garbage as a
912 response to the "info frame" command. */
915 dwarf2_frame_base_address (struct frame_info
*next_frame
, void **this_cache
)
917 struct dwarf2_frame_cache
*cache
=
918 dwarf2_frame_cache (next_frame
, this_cache
);
923 static const struct frame_base dwarf2_frame_base
=
925 &dwarf2_frame_unwind
,
926 dwarf2_frame_base_address
,
927 dwarf2_frame_base_address
,
928 dwarf2_frame_base_address
931 const struct frame_base
*
932 dwarf2_frame_base_sniffer (struct frame_info
*next_frame
)
934 CORE_ADDR pc
= frame_pc_unwind (next_frame
);
935 if (dwarf2_frame_find_fde (&pc
))
936 return &dwarf2_frame_base
;
941 /* A minimal decoding of DWARF2 compilation units. We only decode
942 what's needed to get to the call frame information. */
946 /* Keep the bfd convenient. */
949 struct objfile
*objfile
;
951 /* Linked list of CIEs for this object. */
952 struct dwarf2_cie
*cie
;
954 /* Pointer to the .debug_frame section loaded into memory. */
955 char *dwarf_frame_buffer
;
957 /* Length of the loaded .debug_frame section. */
958 unsigned long dwarf_frame_size
;
960 /* Pointer to the .debug_frame section. */
961 asection
*dwarf_frame_section
;
963 /* Base for DW_EH_PE_datarel encodings. */
966 /* Base for DW_EH_PE_textrel encodings. */
970 const struct objfile_data
*dwarf2_frame_objfile_data
;
973 read_1_byte (bfd
*bfd
, char *buf
)
975 return bfd_get_8 (abfd
, (bfd_byte
*) buf
);
979 read_4_bytes (bfd
*abfd
, char *buf
)
981 return bfd_get_32 (abfd
, (bfd_byte
*) buf
);
985 read_8_bytes (bfd
*abfd
, char *buf
)
987 return bfd_get_64 (abfd
, (bfd_byte
*) buf
);
991 read_unsigned_leb128 (bfd
*abfd
, char *buf
, unsigned int *bytes_read_ptr
)
994 unsigned int num_read
;
1004 byte
= bfd_get_8 (abfd
, (bfd_byte
*) buf
);
1007 result
|= ((byte
& 0x7f) << shift
);
1010 while (byte
& 0x80);
1012 *bytes_read_ptr
= num_read
;
1018 read_signed_leb128 (bfd
*abfd
, char *buf
, unsigned int *bytes_read_ptr
)
1022 unsigned int num_read
;
1031 byte
= bfd_get_8 (abfd
, (bfd_byte
*) buf
);
1034 result
|= ((byte
& 0x7f) << shift
);
1037 while (byte
& 0x80);
1039 if ((shift
< 32) && (byte
& 0x40))
1040 result
|= -(1 << shift
);
1042 *bytes_read_ptr
= num_read
;
1048 read_initial_length (bfd
*abfd
, char *buf
, unsigned int *bytes_read_ptr
)
1052 result
= bfd_get_32 (abfd
, (bfd_byte
*) buf
);
1053 if (result
== 0xffffffff)
1055 result
= bfd_get_64 (abfd
, (bfd_byte
*) buf
+ 4);
1056 *bytes_read_ptr
= 12;
1059 *bytes_read_ptr
= 4;
1065 /* Pointer encoding helper functions. */
1067 /* GCC supports exception handling based on DWARF2 CFI. However, for
1068 technical reasons, it encodes addresses in its FDE's in a different
1069 way. Several "pointer encodings" are supported. The encoding
1070 that's used for a particular FDE is determined by the 'R'
1071 augmentation in the associated CIE. The argument of this
1072 augmentation is a single byte.
1074 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1075 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1076 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1077 address should be interpreted (absolute, relative to the current
1078 position in the FDE, ...). Bit 7, indicates that the address
1079 should be dereferenced. */
1081 static unsigned char
1082 encoding_for_size (unsigned int size
)
1087 return DW_EH_PE_udata2
;
1089 return DW_EH_PE_udata4
;
1091 return DW_EH_PE_udata8
;
1093 internal_error (__FILE__
, __LINE__
, "Unsupported address size");
1098 size_of_encoded_value (unsigned char encoding
)
1100 if (encoding
== DW_EH_PE_omit
)
1103 switch (encoding
& 0x07)
1105 case DW_EH_PE_absptr
:
1106 return TYPE_LENGTH (builtin_type_void_data_ptr
);
1107 case DW_EH_PE_udata2
:
1109 case DW_EH_PE_udata4
:
1111 case DW_EH_PE_udata8
:
1114 internal_error (__FILE__
, __LINE__
, "Invalid or unsupported encoding");
1119 read_encoded_value (struct comp_unit
*unit
, unsigned char encoding
,
1120 unsigned char *buf
, unsigned int *bytes_read_ptr
)
1122 int ptr_len
= size_of_encoded_value (DW_EH_PE_absptr
);
1126 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1128 if (encoding
& DW_EH_PE_indirect
)
1129 internal_error (__FILE__
, __LINE__
,
1130 "Unsupported encoding: DW_EH_PE_indirect");
1132 *bytes_read_ptr
= 0;
1134 switch (encoding
& 0x70)
1136 case DW_EH_PE_absptr
:
1139 case DW_EH_PE_pcrel
:
1140 base
= bfd_get_section_vma (unit
->bfd
, unit
->dwarf_frame_section
);
1141 base
+= ((char *) buf
- unit
->dwarf_frame_buffer
);
1143 case DW_EH_PE_datarel
:
1146 case DW_EH_PE_textrel
:
1149 case DW_EH_PE_funcrel
:
1150 /* FIXME: kettenis/20040501: For now just pretend
1151 DW_EH_PE_funcrel is equivalent to DW_EH_PE_absptr. For
1152 reading the initial location of an FDE it should be treated
1153 as such, and currently that's the only place where this code
1157 case DW_EH_PE_aligned
:
1159 offset
= (char *) buf
- unit
->dwarf_frame_buffer
;
1160 if ((offset
% ptr_len
) != 0)
1162 *bytes_read_ptr
= ptr_len
- (offset
% ptr_len
);
1163 buf
+= *bytes_read_ptr
;
1167 internal_error (__FILE__
, __LINE__
, "Invalid or unsupported encoding");
1170 if ((encoding
& 0x07) == 0x00)
1171 encoding
|= encoding_for_size (ptr_len
);
1173 switch (encoding
& 0x0f)
1175 case DW_EH_PE_uleb128
:
1178 unsigned char *end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1179 *bytes_read_ptr
= read_uleb128 (buf
, end_buf
, &value
) - buf
;
1180 return base
+ value
;
1182 case DW_EH_PE_udata2
:
1183 *bytes_read_ptr
+= 2;
1184 return (base
+ bfd_get_16 (unit
->abfd
, (bfd_byte
*) buf
));
1185 case DW_EH_PE_udata4
:
1186 *bytes_read_ptr
+= 4;
1187 return (base
+ bfd_get_32 (unit
->abfd
, (bfd_byte
*) buf
));
1188 case DW_EH_PE_udata8
:
1189 *bytes_read_ptr
+= 8;
1190 return (base
+ bfd_get_64 (unit
->abfd
, (bfd_byte
*) buf
));
1191 case DW_EH_PE_sleb128
:
1194 char *end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1195 *bytes_read_ptr
= read_sleb128 (buf
, end_buf
, &value
) - buf
;
1196 return base
+ value
;
1198 case DW_EH_PE_sdata2
:
1199 *bytes_read_ptr
+= 2;
1200 return (base
+ bfd_get_signed_16 (unit
->abfd
, (bfd_byte
*) buf
));
1201 case DW_EH_PE_sdata4
:
1202 *bytes_read_ptr
+= 4;
1203 return (base
+ bfd_get_signed_32 (unit
->abfd
, (bfd_byte
*) buf
));
1204 case DW_EH_PE_sdata8
:
1205 *bytes_read_ptr
+= 8;
1206 return (base
+ bfd_get_signed_64 (unit
->abfd
, (bfd_byte
*) buf
));
1208 internal_error (__FILE__
, __LINE__
, "Invalid or unsupported encoding");
1213 /* GCC uses a single CIE for all FDEs in a .debug_frame section.
1214 That's why we use a simple linked list here. */
1216 static struct dwarf2_cie
*
1217 find_cie (struct comp_unit
*unit
, ULONGEST cie_pointer
)
1219 struct dwarf2_cie
*cie
= unit
->cie
;
1223 if (cie
->cie_pointer
== cie_pointer
)
1233 add_cie (struct comp_unit
*unit
, struct dwarf2_cie
*cie
)
1235 cie
->next
= unit
->cie
;
1239 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1240 inital location associated with it into *PC. */
1242 static struct dwarf2_fde
*
1243 dwarf2_frame_find_fde (CORE_ADDR
*pc
)
1245 struct objfile
*objfile
;
1247 ALL_OBJFILES (objfile
)
1249 struct dwarf2_fde
*fde
;
1252 fde
= objfile_data (objfile
, dwarf2_frame_objfile_data
);
1256 gdb_assert (objfile
->section_offsets
);
1257 offset
= ANOFFSET (objfile
->section_offsets
, SECT_OFF_TEXT (objfile
));
1261 if (*pc
>= fde
->initial_location
+ offset
1262 && *pc
< fde
->initial_location
+ offset
+ fde
->address_range
)
1264 *pc
= fde
->initial_location
+ offset
;
1276 add_fde (struct comp_unit
*unit
, struct dwarf2_fde
*fde
)
1278 fde
->next
= objfile_data (unit
->objfile
, dwarf2_frame_objfile_data
);
1279 set_objfile_data (unit
->objfile
, dwarf2_frame_objfile_data
, fde
);
1282 #ifdef CC_HAS_LONG_LONG
1283 #define DW64_CIE_ID 0xffffffffffffffffULL
1285 #define DW64_CIE_ID ~0
1288 static char *decode_frame_entry (struct comp_unit
*unit
, char *start
,
1291 /* Decode the next CIE or FDE. Return NULL if invalid input, otherwise
1292 the next byte to be processed. */
1294 decode_frame_entry_1 (struct comp_unit
*unit
, char *start
, int eh_frame_p
)
1298 unsigned int bytes_read
;
1301 ULONGEST cie_pointer
;
1305 length
= read_initial_length (unit
->abfd
, buf
, &bytes_read
);
1309 /* Are we still within the section? */
1310 if (end
> unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
1316 /* Distinguish between 32 and 64-bit encoded frame info. */
1317 dwarf64_p
= (bytes_read
== 12);
1319 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1323 cie_id
= DW64_CIE_ID
;
1329 cie_pointer
= read_8_bytes (unit
->abfd
, buf
);
1334 cie_pointer
= read_4_bytes (unit
->abfd
, buf
);
1338 if (cie_pointer
== cie_id
)
1340 /* This is a CIE. */
1341 struct dwarf2_cie
*cie
;
1343 unsigned int cie_version
;
1345 /* Record the offset into the .debug_frame section of this CIE. */
1346 cie_pointer
= start
- unit
->dwarf_frame_buffer
;
1348 /* Check whether we've already read it. */
1349 if (find_cie (unit
, cie_pointer
))
1352 cie
= (struct dwarf2_cie
*)
1353 obstack_alloc (&unit
->objfile
->objfile_obstack
,
1354 sizeof (struct dwarf2_cie
));
1355 cie
->initial_instructions
= NULL
;
1356 cie
->cie_pointer
= cie_pointer
;
1358 /* The encoding for FDE's in a normal .debug_frame section
1359 depends on the target address size. */
1360 cie
->encoding
= DW_EH_PE_absptr
;
1362 /* Check version number. */
1363 cie_version
= read_1_byte (unit
->abfd
, buf
);
1364 if (cie_version
!= 1 && cie_version
!= 3)
1368 /* Interpret the interesting bits of the augmentation. */
1370 buf
= augmentation
+ strlen (augmentation
) + 1;
1372 /* The GCC 2.x "eh" augmentation has a pointer immediately
1373 following the augmentation string, so it must be handled
1375 if (augmentation
[0] == 'e' && augmentation
[1] == 'h')
1378 buf
+= TYPE_LENGTH (builtin_type_void_data_ptr
);
1382 cie
->code_alignment_factor
=
1383 read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1386 cie
->data_alignment_factor
=
1387 read_signed_leb128 (unit
->abfd
, buf
, &bytes_read
);
1390 if (cie_version
== 1)
1392 cie
->return_address_register
= read_1_byte (unit
->abfd
, buf
);
1396 cie
->return_address_register
= read_unsigned_leb128 (unit
->abfd
, buf
,
1400 cie
->saw_z_augmentation
= (*augmentation
== 'z');
1401 if (cie
->saw_z_augmentation
)
1405 length
= read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1409 cie
->initial_instructions
= buf
+ length
;
1413 while (*augmentation
)
1415 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1416 if (*augmentation
== 'L')
1423 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1424 else if (*augmentation
== 'R')
1426 cie
->encoding
= *buf
++;
1430 /* "P" indicates a personality routine in the CIE augmentation. */
1431 else if (*augmentation
== 'P')
1433 /* Skip. Avoid indirection since we throw away the result. */
1434 unsigned char encoding
= (*buf
++) & ~DW_EH_PE_indirect
;
1435 read_encoded_value (unit
, encoding
, buf
, &bytes_read
);
1440 /* Otherwise we have an unknown augmentation.
1441 Bail out unless we saw a 'z' prefix. */
1444 if (cie
->initial_instructions
== NULL
)
1447 /* Skip unknown augmentations. */
1448 buf
= cie
->initial_instructions
;
1453 cie
->initial_instructions
= buf
;
1456 add_cie (unit
, cie
);
1460 /* This is a FDE. */
1461 struct dwarf2_fde
*fde
;
1463 /* In an .eh_frame section, the CIE pointer is the delta between the
1464 address within the FDE where the CIE pointer is stored and the
1465 address of the CIE. Convert it to an offset into the .eh_frame
1469 cie_pointer
= buf
- unit
->dwarf_frame_buffer
- cie_pointer
;
1470 cie_pointer
-= (dwarf64_p
? 8 : 4);
1473 /* In either case, validate the result is still within the section. */
1474 if (cie_pointer
>= unit
->dwarf_frame_size
)
1477 fde
= (struct dwarf2_fde
*)
1478 obstack_alloc (&unit
->objfile
->objfile_obstack
,
1479 sizeof (struct dwarf2_fde
));
1480 fde
->cie
= find_cie (unit
, cie_pointer
);
1481 if (fde
->cie
== NULL
)
1483 decode_frame_entry (unit
, unit
->dwarf_frame_buffer
+ cie_pointer
,
1485 fde
->cie
= find_cie (unit
, cie_pointer
);
1488 gdb_assert (fde
->cie
!= NULL
);
1490 fde
->initial_location
=
1491 read_encoded_value (unit
, fde
->cie
->encoding
, buf
, &bytes_read
);
1494 fde
->address_range
=
1495 read_encoded_value (unit
, fde
->cie
->encoding
& 0x0f, buf
, &bytes_read
);
1498 /* A 'z' augmentation in the CIE implies the presence of an
1499 augmentation field in the FDE as well. The only thing known
1500 to be in here at present is the LSDA entry for EH. So we
1501 can skip the whole thing. */
1502 if (fde
->cie
->saw_z_augmentation
)
1506 length
= read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1507 buf
+= bytes_read
+ length
;
1512 fde
->instructions
= buf
;
1515 add_fde (unit
, fde
);
1521 /* Read a CIE or FDE in BUF and decode it. */
1523 decode_frame_entry (struct comp_unit
*unit
, char *start
, int eh_frame_p
)
1525 enum { NONE
, ALIGN4
, ALIGN8
, FAIL
} workaround
= NONE
;
1528 ptrdiff_t start_offset
;
1532 ret
= decode_frame_entry_1 (unit
, start
, eh_frame_p
);
1536 /* We have corrupt input data of some form. */
1538 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
1539 and mismatches wrt padding and alignment of debug sections. */
1540 /* Note that there is no requirement in the standard for any
1541 alignment at all in the frame unwind sections. Testing for
1542 alignment before trying to interpret data would be incorrect.
1544 However, GCC traditionally arranged for frame sections to be
1545 sized such that the FDE length and CIE fields happen to be
1546 aligned (in theory, for performance). This, unfortunately,
1547 was done with .align directives, which had the side effect of
1548 forcing the section to be aligned by the linker.
1550 This becomes a problem when you have some other producer that
1551 creates frame sections that are not as strictly aligned. That
1552 produces a hole in the frame info that gets filled by the
1555 The GCC behaviour is arguably a bug, but it's effectively now
1556 part of the ABI, so we're now stuck with it, at least at the
1557 object file level. A smart linker may decide, in the process
1558 of compressing duplicate CIE information, that it can rewrite
1559 the entire output section without this extra padding. */
1561 start_offset
= start
- unit
->dwarf_frame_buffer
;
1562 if (workaround
< ALIGN4
&& (start_offset
& 3) != 0)
1564 start
+= 4 - (start_offset
& 3);
1565 workaround
= ALIGN4
;
1568 if (workaround
< ALIGN8
&& (start_offset
& 7) != 0)
1570 start
+= 8 - (start_offset
& 7);
1571 workaround
= ALIGN8
;
1575 /* Nothing left to try. Arrange to return as if we've consumed
1576 the entire input section. Hopefully we'll get valid info from
1577 the other of .debug_frame/.eh_frame. */
1579 ret
= unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
;
1589 complaint (&symfile_complaints
,
1590 "Corrupt data in %s:%s; align 4 workaround apparently succeeded",
1591 unit
->dwarf_frame_section
->owner
->filename
,
1592 unit
->dwarf_frame_section
->name
);
1596 complaint (&symfile_complaints
,
1597 "Corrupt data in %s:%s; align 8 workaround apparently succeeded",
1598 unit
->dwarf_frame_section
->owner
->filename
,
1599 unit
->dwarf_frame_section
->name
);
1603 complaint (&symfile_complaints
,
1604 "Corrupt data in %s:%s",
1605 unit
->dwarf_frame_section
->owner
->filename
,
1606 unit
->dwarf_frame_section
->name
);
1614 /* FIXME: kettenis/20030504: This still needs to be integrated with
1615 dwarf2read.c in a better way. */
1617 /* Imported from dwarf2read.c. */
1618 extern asection
*dwarf_frame_section
;
1619 extern asection
*dwarf_eh_frame_section
;
1621 /* Imported from dwarf2read.c. */
1622 extern char *dwarf2_read_section (struct objfile
*objfile
, asection
*sectp
);
1625 dwarf2_build_frame_info (struct objfile
*objfile
)
1627 struct comp_unit unit
;
1630 /* Build a minimal decoding of the DWARF2 compilation unit. */
1631 unit
.abfd
= objfile
->obfd
;
1632 unit
.objfile
= objfile
;
1636 /* First add the information from the .eh_frame section. That way,
1637 the FDEs from that section are searched last. */
1638 if (dwarf_eh_frame_section
)
1640 asection
*got
, *txt
;
1643 unit
.dwarf_frame_buffer
= dwarf2_read_section (objfile
,
1644 dwarf_eh_frame_section
);
1646 unit
.dwarf_frame_size
= bfd_get_section_size (dwarf_eh_frame_section
);
1647 unit
.dwarf_frame_section
= dwarf_eh_frame_section
;
1649 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
1650 that is used for the i386/amd64 target, which currently is
1651 the only target in GCC that supports/uses the
1652 DW_EH_PE_datarel encoding. */
1653 got
= bfd_get_section_by_name (unit
.abfd
, ".got");
1655 unit
.dbase
= got
->vma
;
1657 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
1659 txt
= bfd_get_section_by_name (unit
.abfd
, ".text");
1661 unit
.tbase
= txt
->vma
;
1663 frame_ptr
= unit
.dwarf_frame_buffer
;
1664 while (frame_ptr
< unit
.dwarf_frame_buffer
+ unit
.dwarf_frame_size
)
1665 frame_ptr
= decode_frame_entry (&unit
, frame_ptr
, 1);
1668 if (dwarf_frame_section
)
1671 unit
.dwarf_frame_buffer
= dwarf2_read_section (objfile
,
1672 dwarf_frame_section
);
1673 unit
.dwarf_frame_size
= bfd_get_section_size (dwarf_frame_section
);
1674 unit
.dwarf_frame_section
= dwarf_frame_section
;
1676 frame_ptr
= unit
.dwarf_frame_buffer
;
1677 while (frame_ptr
< unit
.dwarf_frame_buffer
+ unit
.dwarf_frame_size
)
1678 frame_ptr
= decode_frame_entry (&unit
, frame_ptr
, 0);
1682 /* Provide a prototype to silence -Wmissing-prototypes. */
1683 void _initialize_dwarf2_frame (void);
1686 _initialize_dwarf2_frame (void)
1688 dwarf2_frame_data
= gdbarch_data_register_pre_init (dwarf2_frame_init
);
1689 dwarf2_frame_objfile_data
= register_objfile_data ();