1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright 2003, 2004, 2005 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
;
592 /* Return address register. */
593 struct dwarf2_frame_state_reg retaddr_reg
;
596 static struct dwarf2_frame_cache
*
597 dwarf2_frame_cache (struct frame_info
*next_frame
, void **this_cache
)
599 struct cleanup
*old_chain
;
600 struct gdbarch
*gdbarch
= get_frame_arch (next_frame
);
601 const int num_regs
= NUM_REGS
+ NUM_PSEUDO_REGS
;
602 struct dwarf2_frame_cache
*cache
;
603 struct dwarf2_frame_state
*fs
;
604 struct dwarf2_fde
*fde
;
609 /* Allocate a new cache. */
610 cache
= FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache
);
611 cache
->reg
= FRAME_OBSTACK_CALLOC (num_regs
, struct dwarf2_frame_state_reg
);
613 /* Allocate and initialize the frame state. */
614 fs
= XMALLOC (struct dwarf2_frame_state
);
615 memset (fs
, 0, sizeof (struct dwarf2_frame_state
));
616 old_chain
= make_cleanup (dwarf2_frame_state_free
, fs
);
620 Note that if NEXT_FRAME is never supposed to return (i.e. a call
621 to abort), the compiler might optimize away the instruction at
622 NEXT_FRAME's return address. As a result the return address will
623 point at some random instruction, and the CFI for that
624 instruction is probably worthless to us. GCC's unwinder solves
625 this problem by substracting 1 from the return address to get an
626 address in the middle of a presumed call instruction (or the
627 instruction in the associated delay slot). This should only be
628 done for "normal" frames and not for resume-type frames (signal
629 handlers, sentinel frames, dummy frames). The function
630 frame_unwind_address_in_block does just this. It's not clear how
631 reliable the method is though; there is the potential for the
632 register state pre-call being different to that on return. */
633 fs
->pc
= frame_unwind_address_in_block (next_frame
);
635 /* Find the correct FDE. */
636 fde
= dwarf2_frame_find_fde (&fs
->pc
);
637 gdb_assert (fde
!= NULL
);
639 /* Extract any interesting information from the CIE. */
640 fs
->data_align
= fde
->cie
->data_alignment_factor
;
641 fs
->code_align
= fde
->cie
->code_alignment_factor
;
642 fs
->retaddr_column
= fde
->cie
->return_address_register
;
644 /* First decode all the insns in the CIE. */
645 execute_cfa_program (fde
->cie
->initial_instructions
,
646 fde
->cie
->end
, next_frame
, fs
);
648 /* Save the initialized register set. */
649 fs
->initial
= fs
->regs
;
650 fs
->initial
.reg
= dwarf2_frame_state_copy_regs (&fs
->regs
);
652 /* Then decode the insns in the FDE up to our target PC. */
653 execute_cfa_program (fde
->instructions
, fde
->end
, next_frame
, fs
);
655 /* Caclulate the CFA. */
659 cache
->cfa
= read_reg (next_frame
, fs
->cfa_reg
);
660 cache
->cfa
+= fs
->cfa_offset
;
665 execute_stack_op (fs
->cfa_exp
, fs
->cfa_exp_len
, next_frame
, 0);
669 internal_error (__FILE__
, __LINE__
, _("Unknown CFA rule."));
672 /* Initialize the register state. */
676 for (regnum
= 0; regnum
< num_regs
; regnum
++)
677 dwarf2_frame_init_reg (gdbarch
, regnum
, &cache
->reg
[regnum
]);
680 /* Go through the DWARF2 CFI generated table and save its register
681 location information in the cache. Note that we don't skip the
682 return address column; it's perfectly all right for it to
683 correspond to a real register. If it doesn't correspond to a
684 real register, or if we shouldn't treat it as such,
685 DWARF2_REG_TO_REGNUM should be defined to return a number outside
686 the range [0, NUM_REGS). */
688 int column
; /* CFI speak for "register number". */
690 for (column
= 0; column
< fs
->regs
.num_regs
; column
++)
692 /* Use the GDB register number as the destination index. */
693 int regnum
= DWARF2_REG_TO_REGNUM (column
);
695 /* If there's no corresponding GDB register, ignore it. */
696 if (regnum
< 0 || regnum
>= num_regs
)
699 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
700 of all debug info registers. If it doesn't, complain (but
701 not too loudly). It turns out that GCC assumes that an
702 unspecified register implies "same value" when CFI (draft
703 7) specifies nothing at all. Such a register could equally
704 be interpreted as "undefined". Also note that this check
705 isn't sufficient; it only checks that all registers in the
706 range [0 .. max column] are specified, and won't detect
707 problems when a debug info register falls outside of the
708 table. We need a way of iterating through all the valid
709 DWARF2 register numbers. */
710 if (fs
->regs
.reg
[column
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
712 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_UNSPECIFIED
)
713 complaint (&symfile_complaints
, _("\
714 incomplete CFI data; unspecified registers (e.g., %s) at 0x%s"),
715 gdbarch_register_name (gdbarch
, regnum
),
719 cache
->reg
[regnum
] = fs
->regs
.reg
[column
];
723 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
724 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
728 for (regnum
= 0; regnum
< num_regs
; regnum
++)
730 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
731 || cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA_OFFSET
)
733 struct dwarf2_frame_state_reg
*retaddr_reg
=
734 &fs
->regs
.reg
[fs
->retaddr_column
];
736 /* It seems rather bizarre to specify an "empty" column as
737 the return adress column. However, this is exactly
738 what GCC does on some targets. It turns out that GCC
739 assumes that the return address can be found in the
740 register corresponding to the return address column.
741 Incidentally, that's how we should treat a return
742 address column specifying "same value" too. */
743 if (fs
->retaddr_column
< fs
->regs
.num_regs
744 && retaddr_reg
->how
!= DWARF2_FRAME_REG_UNSPECIFIED
745 && retaddr_reg
->how
!= DWARF2_FRAME_REG_SAME_VALUE
)
747 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
748 cache
->reg
[regnum
] = *retaddr_reg
;
750 cache
->retaddr_reg
= *retaddr_reg
;
754 if (cache
->reg
[regnum
].how
== DWARF2_FRAME_REG_RA
)
756 cache
->reg
[regnum
].loc
.reg
= fs
->retaddr_column
;
757 cache
->reg
[regnum
].how
= DWARF2_FRAME_REG_SAVED_REG
;
761 cache
->retaddr_reg
.loc
.reg
= fs
->retaddr_column
;
762 cache
->retaddr_reg
.how
= DWARF2_FRAME_REG_SAVED_REG
;
769 do_cleanups (old_chain
);
776 dwarf2_frame_this_id (struct frame_info
*next_frame
, void **this_cache
,
777 struct frame_id
*this_id
)
779 struct dwarf2_frame_cache
*cache
=
780 dwarf2_frame_cache (next_frame
, this_cache
);
782 (*this_id
) = frame_id_build (cache
->cfa
, frame_func_unwind (next_frame
));
786 dwarf2_frame_prev_register (struct frame_info
*next_frame
, void **this_cache
,
787 int regnum
, int *optimizedp
,
788 enum lval_type
*lvalp
, CORE_ADDR
*addrp
,
789 int *realnump
, void *valuep
)
791 struct gdbarch
*gdbarch
= get_frame_arch (next_frame
);
792 struct dwarf2_frame_cache
*cache
=
793 dwarf2_frame_cache (next_frame
, this_cache
);
795 switch (cache
->reg
[regnum
].how
)
797 case DWARF2_FRAME_REG_UNDEFINED
:
798 /* If CFI explicitly specified that the value isn't defined,
799 mark it as optimized away; the value isn't available. */
806 /* In some cases, for example %eflags on the i386, we have
807 to provide a sane value, even though this register wasn't
808 saved. Assume we can get it from NEXT_FRAME. */
809 frame_unwind_register (next_frame
, regnum
, valuep
);
813 case DWARF2_FRAME_REG_SAVED_OFFSET
:
815 *lvalp
= lval_memory
;
816 *addrp
= cache
->cfa
+ cache
->reg
[regnum
].loc
.offset
;
820 /* Read the value in from memory. */
821 read_memory (*addrp
, valuep
, register_size (gdbarch
, regnum
));
825 case DWARF2_FRAME_REG_SAVED_REG
:
827 *lvalp
= lval_register
;
829 *realnump
= DWARF2_REG_TO_REGNUM (cache
->reg
[regnum
].loc
.reg
);
831 frame_unwind_register (next_frame
, (*realnump
), valuep
);
834 case DWARF2_FRAME_REG_SAVED_EXP
:
836 *lvalp
= lval_memory
;
837 *addrp
= execute_stack_op (cache
->reg
[regnum
].loc
.exp
,
838 cache
->reg
[regnum
].exp_len
,
839 next_frame
, cache
->cfa
);
843 /* Read the value in from memory. */
844 read_memory (*addrp
, valuep
, register_size (gdbarch
, regnum
));
848 case DWARF2_FRAME_REG_UNSPECIFIED
:
849 /* GCC, in its infinite wisdom decided to not provide unwind
850 information for registers that are "same value". Since
851 DWARF2 (3 draft 7) doesn't define such behavior, said
852 registers are actually undefined (which is different to CFI
853 "undefined"). Code above issues a complaint about this.
854 Here just fudge the books, assume GCC, and that the value is
855 more inner on the stack. */
857 *lvalp
= lval_register
;
861 frame_unwind_register (next_frame
, (*realnump
), valuep
);
864 case DWARF2_FRAME_REG_SAME_VALUE
:
866 *lvalp
= lval_register
;
870 frame_unwind_register (next_frame
, (*realnump
), valuep
);
873 case DWARF2_FRAME_REG_CFA
:
880 /* Store the value. */
881 store_typed_address (valuep
, builtin_type_void_data_ptr
, cache
->cfa
);
885 case DWARF2_FRAME_REG_RA_OFFSET
:
892 CORE_ADDR pc
= cache
->reg
[regnum
].loc
.offset
;
894 regnum
= DWARF2_REG_TO_REGNUM (cache
->retaddr_reg
.loc
.reg
);
895 pc
+= frame_unwind_register_unsigned (next_frame
, regnum
);
896 store_typed_address (valuep
, builtin_type_void_func_ptr
, pc
);
901 internal_error (__FILE__
, __LINE__
, _("Unknown register rule."));
905 static const struct frame_unwind dwarf2_frame_unwind
=
908 dwarf2_frame_this_id
,
909 dwarf2_frame_prev_register
912 static const struct frame_unwind dwarf2_signal_frame_unwind
=
915 dwarf2_frame_this_id
,
916 dwarf2_frame_prev_register
919 const struct frame_unwind
*
920 dwarf2_frame_sniffer (struct frame_info
*next_frame
)
922 /* Grab an address that is guarenteed to reside somewhere within the
923 function. frame_pc_unwind(), for a no-return next function, can
924 end up returning something past the end of this function's body. */
925 CORE_ADDR block_addr
= frame_unwind_address_in_block (next_frame
);
926 if (!dwarf2_frame_find_fde (&block_addr
))
929 /* On some targets, signal trampolines may have unwind information.
930 We need to recognize them so that we set the frame type
933 if (dwarf2_frame_signal_frame_p (get_frame_arch (next_frame
),
935 return &dwarf2_signal_frame_unwind
;
937 return &dwarf2_frame_unwind
;
941 /* There is no explicitly defined relationship between the CFA and the
942 location of frame's local variables and arguments/parameters.
943 Therefore, frame base methods on this page should probably only be
944 used as a last resort, just to avoid printing total garbage as a
945 response to the "info frame" command. */
948 dwarf2_frame_base_address (struct frame_info
*next_frame
, void **this_cache
)
950 struct dwarf2_frame_cache
*cache
=
951 dwarf2_frame_cache (next_frame
, this_cache
);
956 static const struct frame_base dwarf2_frame_base
=
958 &dwarf2_frame_unwind
,
959 dwarf2_frame_base_address
,
960 dwarf2_frame_base_address
,
961 dwarf2_frame_base_address
964 const struct frame_base
*
965 dwarf2_frame_base_sniffer (struct frame_info
*next_frame
)
967 CORE_ADDR pc
= frame_pc_unwind (next_frame
);
968 if (dwarf2_frame_find_fde (&pc
))
969 return &dwarf2_frame_base
;
974 /* A minimal decoding of DWARF2 compilation units. We only decode
975 what's needed to get to the call frame information. */
979 /* Keep the bfd convenient. */
982 struct objfile
*objfile
;
984 /* Linked list of CIEs for this object. */
985 struct dwarf2_cie
*cie
;
987 /* Pointer to the .debug_frame section loaded into memory. */
988 char *dwarf_frame_buffer
;
990 /* Length of the loaded .debug_frame section. */
991 unsigned long dwarf_frame_size
;
993 /* Pointer to the .debug_frame section. */
994 asection
*dwarf_frame_section
;
996 /* Base for DW_EH_PE_datarel encodings. */
999 /* Base for DW_EH_PE_textrel encodings. */
1003 const struct objfile_data
*dwarf2_frame_objfile_data
;
1006 read_1_byte (bfd
*bfd
, char *buf
)
1008 return bfd_get_8 (abfd
, (bfd_byte
*) buf
);
1012 read_4_bytes (bfd
*abfd
, char *buf
)
1014 return bfd_get_32 (abfd
, (bfd_byte
*) buf
);
1018 read_8_bytes (bfd
*abfd
, char *buf
)
1020 return bfd_get_64 (abfd
, (bfd_byte
*) buf
);
1024 read_unsigned_leb128 (bfd
*abfd
, char *buf
, unsigned int *bytes_read_ptr
)
1027 unsigned int num_read
;
1037 byte
= bfd_get_8 (abfd
, (bfd_byte
*) buf
);
1040 result
|= ((byte
& 0x7f) << shift
);
1043 while (byte
& 0x80);
1045 *bytes_read_ptr
= num_read
;
1051 read_signed_leb128 (bfd
*abfd
, char *buf
, unsigned int *bytes_read_ptr
)
1055 unsigned int num_read
;
1064 byte
= bfd_get_8 (abfd
, (bfd_byte
*) buf
);
1067 result
|= ((byte
& 0x7f) << shift
);
1070 while (byte
& 0x80);
1072 if ((shift
< 32) && (byte
& 0x40))
1073 result
|= -(1 << shift
);
1075 *bytes_read_ptr
= num_read
;
1081 read_initial_length (bfd
*abfd
, char *buf
, unsigned int *bytes_read_ptr
)
1085 result
= bfd_get_32 (abfd
, (bfd_byte
*) buf
);
1086 if (result
== 0xffffffff)
1088 result
= bfd_get_64 (abfd
, (bfd_byte
*) buf
+ 4);
1089 *bytes_read_ptr
= 12;
1092 *bytes_read_ptr
= 4;
1098 /* Pointer encoding helper functions. */
1100 /* GCC supports exception handling based on DWARF2 CFI. However, for
1101 technical reasons, it encodes addresses in its FDE's in a different
1102 way. Several "pointer encodings" are supported. The encoding
1103 that's used for a particular FDE is determined by the 'R'
1104 augmentation in the associated CIE. The argument of this
1105 augmentation is a single byte.
1107 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1108 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1109 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1110 address should be interpreted (absolute, relative to the current
1111 position in the FDE, ...). Bit 7, indicates that the address
1112 should be dereferenced. */
1114 static unsigned char
1115 encoding_for_size (unsigned int size
)
1120 return DW_EH_PE_udata2
;
1122 return DW_EH_PE_udata4
;
1124 return DW_EH_PE_udata8
;
1126 internal_error (__FILE__
, __LINE__
, _("Unsupported address size"));
1131 size_of_encoded_value (unsigned char encoding
)
1133 if (encoding
== DW_EH_PE_omit
)
1136 switch (encoding
& 0x07)
1138 case DW_EH_PE_absptr
:
1139 return TYPE_LENGTH (builtin_type_void_data_ptr
);
1140 case DW_EH_PE_udata2
:
1142 case DW_EH_PE_udata4
:
1144 case DW_EH_PE_udata8
:
1147 internal_error (__FILE__
, __LINE__
, _("Invalid or unsupported encoding"));
1152 read_encoded_value (struct comp_unit
*unit
, unsigned char encoding
,
1153 unsigned char *buf
, unsigned int *bytes_read_ptr
)
1155 int ptr_len
= size_of_encoded_value (DW_EH_PE_absptr
);
1159 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1161 if (encoding
& DW_EH_PE_indirect
)
1162 internal_error (__FILE__
, __LINE__
,
1163 _("Unsupported encoding: DW_EH_PE_indirect"));
1165 *bytes_read_ptr
= 0;
1167 switch (encoding
& 0x70)
1169 case DW_EH_PE_absptr
:
1172 case DW_EH_PE_pcrel
:
1173 base
= bfd_get_section_vma (unit
->bfd
, unit
->dwarf_frame_section
);
1174 base
+= ((char *) buf
- unit
->dwarf_frame_buffer
);
1176 case DW_EH_PE_datarel
:
1179 case DW_EH_PE_textrel
:
1182 case DW_EH_PE_funcrel
:
1183 /* FIXME: kettenis/20040501: For now just pretend
1184 DW_EH_PE_funcrel is equivalent to DW_EH_PE_absptr. For
1185 reading the initial location of an FDE it should be treated
1186 as such, and currently that's the only place where this code
1190 case DW_EH_PE_aligned
:
1192 offset
= (char *) buf
- unit
->dwarf_frame_buffer
;
1193 if ((offset
% ptr_len
) != 0)
1195 *bytes_read_ptr
= ptr_len
- (offset
% ptr_len
);
1196 buf
+= *bytes_read_ptr
;
1200 internal_error (__FILE__
, __LINE__
, _("Invalid or unsupported encoding"));
1203 if ((encoding
& 0x07) == 0x00)
1204 encoding
|= encoding_for_size (ptr_len
);
1206 switch (encoding
& 0x0f)
1208 case DW_EH_PE_uleb128
:
1211 unsigned char *end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1212 *bytes_read_ptr
+= read_uleb128 (buf
, end_buf
, &value
) - buf
;
1213 return base
+ value
;
1215 case DW_EH_PE_udata2
:
1216 *bytes_read_ptr
+= 2;
1217 return (base
+ bfd_get_16 (unit
->abfd
, (bfd_byte
*) buf
));
1218 case DW_EH_PE_udata4
:
1219 *bytes_read_ptr
+= 4;
1220 return (base
+ bfd_get_32 (unit
->abfd
, (bfd_byte
*) buf
));
1221 case DW_EH_PE_udata8
:
1222 *bytes_read_ptr
+= 8;
1223 return (base
+ bfd_get_64 (unit
->abfd
, (bfd_byte
*) buf
));
1224 case DW_EH_PE_sleb128
:
1227 char *end_buf
= buf
+ (sizeof (value
) + 1) * 8 / 7;
1228 *bytes_read_ptr
+= read_sleb128 (buf
, end_buf
, &value
) - buf
;
1229 return base
+ value
;
1231 case DW_EH_PE_sdata2
:
1232 *bytes_read_ptr
+= 2;
1233 return (base
+ bfd_get_signed_16 (unit
->abfd
, (bfd_byte
*) buf
));
1234 case DW_EH_PE_sdata4
:
1235 *bytes_read_ptr
+= 4;
1236 return (base
+ bfd_get_signed_32 (unit
->abfd
, (bfd_byte
*) buf
));
1237 case DW_EH_PE_sdata8
:
1238 *bytes_read_ptr
+= 8;
1239 return (base
+ bfd_get_signed_64 (unit
->abfd
, (bfd_byte
*) buf
));
1241 internal_error (__FILE__
, __LINE__
, _("Invalid or unsupported encoding"));
1246 /* GCC uses a single CIE for all FDEs in a .debug_frame section.
1247 That's why we use a simple linked list here. */
1249 static struct dwarf2_cie
*
1250 find_cie (struct comp_unit
*unit
, ULONGEST cie_pointer
)
1252 struct dwarf2_cie
*cie
= unit
->cie
;
1256 if (cie
->cie_pointer
== cie_pointer
)
1266 add_cie (struct comp_unit
*unit
, struct dwarf2_cie
*cie
)
1268 cie
->next
= unit
->cie
;
1272 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1273 inital location associated with it into *PC. */
1275 static struct dwarf2_fde
*
1276 dwarf2_frame_find_fde (CORE_ADDR
*pc
)
1278 struct objfile
*objfile
;
1280 ALL_OBJFILES (objfile
)
1282 struct dwarf2_fde
*fde
;
1285 fde
= objfile_data (objfile
, dwarf2_frame_objfile_data
);
1289 gdb_assert (objfile
->section_offsets
);
1290 offset
= ANOFFSET (objfile
->section_offsets
, SECT_OFF_TEXT (objfile
));
1294 if (*pc
>= fde
->initial_location
+ offset
1295 && *pc
< fde
->initial_location
+ offset
+ fde
->address_range
)
1297 *pc
= fde
->initial_location
+ offset
;
1309 add_fde (struct comp_unit
*unit
, struct dwarf2_fde
*fde
)
1311 fde
->next
= objfile_data (unit
->objfile
, dwarf2_frame_objfile_data
);
1312 set_objfile_data (unit
->objfile
, dwarf2_frame_objfile_data
, fde
);
1315 #ifdef CC_HAS_LONG_LONG
1316 #define DW64_CIE_ID 0xffffffffffffffffULL
1318 #define DW64_CIE_ID ~0
1321 static char *decode_frame_entry (struct comp_unit
*unit
, char *start
,
1324 /* Decode the next CIE or FDE. Return NULL if invalid input, otherwise
1325 the next byte to be processed. */
1327 decode_frame_entry_1 (struct comp_unit
*unit
, char *start
, int eh_frame_p
)
1331 unsigned int bytes_read
;
1334 ULONGEST cie_pointer
;
1338 length
= read_initial_length (unit
->abfd
, buf
, &bytes_read
);
1342 /* Are we still within the section? */
1343 if (end
> unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
)
1349 /* Distinguish between 32 and 64-bit encoded frame info. */
1350 dwarf64_p
= (bytes_read
== 12);
1352 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1356 cie_id
= DW64_CIE_ID
;
1362 cie_pointer
= read_8_bytes (unit
->abfd
, buf
);
1367 cie_pointer
= read_4_bytes (unit
->abfd
, buf
);
1371 if (cie_pointer
== cie_id
)
1373 /* This is a CIE. */
1374 struct dwarf2_cie
*cie
;
1376 unsigned int cie_version
;
1378 /* Record the offset into the .debug_frame section of this CIE. */
1379 cie_pointer
= start
- unit
->dwarf_frame_buffer
;
1381 /* Check whether we've already read it. */
1382 if (find_cie (unit
, cie_pointer
))
1385 cie
= (struct dwarf2_cie
*)
1386 obstack_alloc (&unit
->objfile
->objfile_obstack
,
1387 sizeof (struct dwarf2_cie
));
1388 cie
->initial_instructions
= NULL
;
1389 cie
->cie_pointer
= cie_pointer
;
1391 /* The encoding for FDE's in a normal .debug_frame section
1392 depends on the target address size. */
1393 cie
->encoding
= DW_EH_PE_absptr
;
1395 /* Check version number. */
1396 cie_version
= read_1_byte (unit
->abfd
, buf
);
1397 if (cie_version
!= 1 && cie_version
!= 3)
1401 /* Interpret the interesting bits of the augmentation. */
1403 buf
= augmentation
+ strlen (augmentation
) + 1;
1405 /* The GCC 2.x "eh" augmentation has a pointer immediately
1406 following the augmentation string, so it must be handled
1408 if (augmentation
[0] == 'e' && augmentation
[1] == 'h')
1411 buf
+= TYPE_LENGTH (builtin_type_void_data_ptr
);
1415 cie
->code_alignment_factor
=
1416 read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1419 cie
->data_alignment_factor
=
1420 read_signed_leb128 (unit
->abfd
, buf
, &bytes_read
);
1423 if (cie_version
== 1)
1425 cie
->return_address_register
= read_1_byte (unit
->abfd
, buf
);
1429 cie
->return_address_register
= read_unsigned_leb128 (unit
->abfd
, buf
,
1433 cie
->saw_z_augmentation
= (*augmentation
== 'z');
1434 if (cie
->saw_z_augmentation
)
1438 length
= read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1442 cie
->initial_instructions
= buf
+ length
;
1446 while (*augmentation
)
1448 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1449 if (*augmentation
== 'L')
1456 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1457 else if (*augmentation
== 'R')
1459 cie
->encoding
= *buf
++;
1463 /* "P" indicates a personality routine in the CIE augmentation. */
1464 else if (*augmentation
== 'P')
1466 /* Skip. Avoid indirection since we throw away the result. */
1467 unsigned char encoding
= (*buf
++) & ~DW_EH_PE_indirect
;
1468 read_encoded_value (unit
, encoding
, buf
, &bytes_read
);
1473 /* Otherwise we have an unknown augmentation.
1474 Bail out unless we saw a 'z' prefix. */
1477 if (cie
->initial_instructions
== NULL
)
1480 /* Skip unknown augmentations. */
1481 buf
= cie
->initial_instructions
;
1486 cie
->initial_instructions
= buf
;
1489 add_cie (unit
, cie
);
1493 /* This is a FDE. */
1494 struct dwarf2_fde
*fde
;
1496 /* In an .eh_frame section, the CIE pointer is the delta between the
1497 address within the FDE where the CIE pointer is stored and the
1498 address of the CIE. Convert it to an offset into the .eh_frame
1502 cie_pointer
= buf
- unit
->dwarf_frame_buffer
- cie_pointer
;
1503 cie_pointer
-= (dwarf64_p
? 8 : 4);
1506 /* In either case, validate the result is still within the section. */
1507 if (cie_pointer
>= unit
->dwarf_frame_size
)
1510 fde
= (struct dwarf2_fde
*)
1511 obstack_alloc (&unit
->objfile
->objfile_obstack
,
1512 sizeof (struct dwarf2_fde
));
1513 fde
->cie
= find_cie (unit
, cie_pointer
);
1514 if (fde
->cie
== NULL
)
1516 decode_frame_entry (unit
, unit
->dwarf_frame_buffer
+ cie_pointer
,
1518 fde
->cie
= find_cie (unit
, cie_pointer
);
1521 gdb_assert (fde
->cie
!= NULL
);
1523 fde
->initial_location
=
1524 read_encoded_value (unit
, fde
->cie
->encoding
, buf
, &bytes_read
);
1527 fde
->address_range
=
1528 read_encoded_value (unit
, fde
->cie
->encoding
& 0x0f, buf
, &bytes_read
);
1531 /* A 'z' augmentation in the CIE implies the presence of an
1532 augmentation field in the FDE as well. The only thing known
1533 to be in here at present is the LSDA entry for EH. So we
1534 can skip the whole thing. */
1535 if (fde
->cie
->saw_z_augmentation
)
1539 length
= read_unsigned_leb128 (unit
->abfd
, buf
, &bytes_read
);
1540 buf
+= bytes_read
+ length
;
1545 fde
->instructions
= buf
;
1548 add_fde (unit
, fde
);
1554 /* Read a CIE or FDE in BUF and decode it. */
1556 decode_frame_entry (struct comp_unit
*unit
, char *start
, int eh_frame_p
)
1558 enum { NONE
, ALIGN4
, ALIGN8
, FAIL
} workaround
= NONE
;
1561 ptrdiff_t start_offset
;
1565 ret
= decode_frame_entry_1 (unit
, start
, eh_frame_p
);
1569 /* We have corrupt input data of some form. */
1571 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
1572 and mismatches wrt padding and alignment of debug sections. */
1573 /* Note that there is no requirement in the standard for any
1574 alignment at all in the frame unwind sections. Testing for
1575 alignment before trying to interpret data would be incorrect.
1577 However, GCC traditionally arranged for frame sections to be
1578 sized such that the FDE length and CIE fields happen to be
1579 aligned (in theory, for performance). This, unfortunately,
1580 was done with .align directives, which had the side effect of
1581 forcing the section to be aligned by the linker.
1583 This becomes a problem when you have some other producer that
1584 creates frame sections that are not as strictly aligned. That
1585 produces a hole in the frame info that gets filled by the
1588 The GCC behaviour is arguably a bug, but it's effectively now
1589 part of the ABI, so we're now stuck with it, at least at the
1590 object file level. A smart linker may decide, in the process
1591 of compressing duplicate CIE information, that it can rewrite
1592 the entire output section without this extra padding. */
1594 start_offset
= start
- unit
->dwarf_frame_buffer
;
1595 if (workaround
< ALIGN4
&& (start_offset
& 3) != 0)
1597 start
+= 4 - (start_offset
& 3);
1598 workaround
= ALIGN4
;
1601 if (workaround
< ALIGN8
&& (start_offset
& 7) != 0)
1603 start
+= 8 - (start_offset
& 7);
1604 workaround
= ALIGN8
;
1608 /* Nothing left to try. Arrange to return as if we've consumed
1609 the entire input section. Hopefully we'll get valid info from
1610 the other of .debug_frame/.eh_frame. */
1612 ret
= unit
->dwarf_frame_buffer
+ unit
->dwarf_frame_size
;
1622 complaint (&symfile_complaints
,
1623 _("Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
1624 unit
->dwarf_frame_section
->owner
->filename
,
1625 unit
->dwarf_frame_section
->name
);
1629 complaint (&symfile_complaints
,
1630 _("Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
1631 unit
->dwarf_frame_section
->owner
->filename
,
1632 unit
->dwarf_frame_section
->name
);
1636 complaint (&symfile_complaints
,
1637 _("Corrupt data in %s:%s"),
1638 unit
->dwarf_frame_section
->owner
->filename
,
1639 unit
->dwarf_frame_section
->name
);
1647 /* FIXME: kettenis/20030504: This still needs to be integrated with
1648 dwarf2read.c in a better way. */
1650 /* Imported from dwarf2read.c. */
1651 extern asection
*dwarf_frame_section
;
1652 extern asection
*dwarf_eh_frame_section
;
1654 /* Imported from dwarf2read.c. */
1655 extern char *dwarf2_read_section (struct objfile
*objfile
, asection
*sectp
);
1658 dwarf2_build_frame_info (struct objfile
*objfile
)
1660 struct comp_unit unit
;
1663 /* Build a minimal decoding of the DWARF2 compilation unit. */
1664 unit
.abfd
= objfile
->obfd
;
1665 unit
.objfile
= objfile
;
1669 /* First add the information from the .eh_frame section. That way,
1670 the FDEs from that section are searched last. */
1671 if (dwarf_eh_frame_section
)
1673 asection
*got
, *txt
;
1676 unit
.dwarf_frame_buffer
= dwarf2_read_section (objfile
,
1677 dwarf_eh_frame_section
);
1679 unit
.dwarf_frame_size
= bfd_get_section_size (dwarf_eh_frame_section
);
1680 unit
.dwarf_frame_section
= dwarf_eh_frame_section
;
1682 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
1683 that is used for the i386/amd64 target, which currently is
1684 the only target in GCC that supports/uses the
1685 DW_EH_PE_datarel encoding. */
1686 got
= bfd_get_section_by_name (unit
.abfd
, ".got");
1688 unit
.dbase
= got
->vma
;
1690 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
1692 txt
= bfd_get_section_by_name (unit
.abfd
, ".text");
1694 unit
.tbase
= txt
->vma
;
1696 frame_ptr
= unit
.dwarf_frame_buffer
;
1697 while (frame_ptr
< unit
.dwarf_frame_buffer
+ unit
.dwarf_frame_size
)
1698 frame_ptr
= decode_frame_entry (&unit
, frame_ptr
, 1);
1701 if (dwarf_frame_section
)
1704 unit
.dwarf_frame_buffer
= dwarf2_read_section (objfile
,
1705 dwarf_frame_section
);
1706 unit
.dwarf_frame_size
= bfd_get_section_size (dwarf_frame_section
);
1707 unit
.dwarf_frame_section
= dwarf_frame_section
;
1709 frame_ptr
= unit
.dwarf_frame_buffer
;
1710 while (frame_ptr
< unit
.dwarf_frame_buffer
+ unit
.dwarf_frame_size
)
1711 frame_ptr
= decode_frame_entry (&unit
, frame_ptr
, 0);
1715 /* Provide a prototype to silence -Wmissing-prototypes. */
1716 void _initialize_dwarf2_frame (void);
1719 _initialize_dwarf2_frame (void)
1721 dwarf2_frame_data
= gdbarch_data_register_pre_init (dwarf2_frame_init
);
1722 dwarf2_frame_objfile_data
= register_objfile_data ();