1 /* DWARF2 exception handling and frame unwind runtime interface routines.
2 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 In addition to the permissions in the GNU General Public License, the
13 Free Software Foundation gives you unlimited permission to link the
14 compiled version of this file into combinations with other programs,
15 and to distribute those combinations without any restriction coming
16 from the use of this file. (The General Public License restrictions
17 do apply in other respects; for example, they cover modification of
18 the file, and distribution when not linked into a combined
21 GCC is distributed in the hope that it will be useful, but WITHOUT
22 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
23 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
24 License for more details.
26 You should have received a copy of the GNU General Public License
27 along with GCC; see the file COPYING. If not, write to the Free
28 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
33 #include "coretypes.h"
37 #ifdef __USING_SJLJ_EXCEPTIONS__
38 # define NO_SIZE_OF_ENCODED_VALUE
40 #include "unwind-pe.h"
41 #include "unwind-dw2-fde.h"
43 #include "unwind-dw2.h"
45 #ifndef __USING_SJLJ_EXCEPTIONS__
47 #ifndef STACK_GROWS_DOWNWARD
48 #define STACK_GROWS_DOWNWARD 0
50 #undef STACK_GROWS_DOWNWARD
51 #define STACK_GROWS_DOWNWARD 1
54 /* Dwarf frame registers used for pre gcc 3.0 compiled glibc. */
55 #ifndef PRE_GCC3_DWARF_FRAME_REGISTERS
56 #define PRE_GCC3_DWARF_FRAME_REGISTERS DWARF_FRAME_REGISTERS
59 #ifndef DWARF_REG_TO_UNWIND_COLUMN
60 #define DWARF_REG_TO_UNWIND_COLUMN(REGNO) (REGNO)
63 /* This is the register and unwind state for a particular frame. This
64 provides the information necessary to unwind up past a frame and return
66 struct _Unwind_Context
68 void *reg
[DWARF_FRAME_REGISTERS
+1];
72 struct dwarf_eh_bases bases
;
73 /* Signal frame context. */
74 #define SIGNAL_FRAME_BIT ((~(_Unwind_Word) 0 >> 1) + 1)
75 /* Context which has version/args_size/by_value fields. */
76 #define EXTENDED_CONTEXT_BIT ((~(_Unwind_Word) 0 >> 2) + 1)
78 /* 0 for now, can be increased when further fields are added to
79 struct _Unwind_Context. */
81 _Unwind_Word args_size
;
82 char by_value
[DWARF_FRAME_REGISTERS
+1];
85 /* Byte size of every register managed by these routines. */
86 static unsigned char dwarf_reg_size_table
[DWARF_FRAME_REGISTERS
+1];
89 /* Read unaligned data from the instruction buffer. */
94 unsigned u2
__attribute__ ((mode (HI
)));
95 unsigned u4
__attribute__ ((mode (SI
)));
96 unsigned u8
__attribute__ ((mode (DI
)));
97 signed s2
__attribute__ ((mode (HI
)));
98 signed s4
__attribute__ ((mode (SI
)));
99 signed s8
__attribute__ ((mode (DI
)));
100 } __attribute__ ((packed
));
102 static void uw_update_context (struct _Unwind_Context
*, _Unwind_FrameState
*);
103 static _Unwind_Reason_Code
uw_frame_state_for (struct _Unwind_Context
*,
104 _Unwind_FrameState
*);
107 read_pointer (const void *p
) { const union unaligned
*up
= p
; return up
->p
; }
110 read_1u (const void *p
) { return *(const unsigned char *) p
; }
113 read_1s (const void *p
) { return *(const signed char *) p
; }
116 read_2u (const void *p
) { const union unaligned
*up
= p
; return up
->u2
; }
119 read_2s (const void *p
) { const union unaligned
*up
= p
; return up
->s2
; }
121 static inline unsigned int
122 read_4u (const void *p
) { const union unaligned
*up
= p
; return up
->u4
; }
125 read_4s (const void *p
) { const union unaligned
*up
= p
; return up
->s4
; }
127 static inline unsigned long
128 read_8u (const void *p
) { const union unaligned
*up
= p
; return up
->u8
; }
130 static inline unsigned long
131 read_8s (const void *p
) { const union unaligned
*up
= p
; return up
->s8
; }
133 static inline _Unwind_Word
134 _Unwind_IsSignalFrame (struct _Unwind_Context
*context
)
136 return (context
->flags
& SIGNAL_FRAME_BIT
) ? 1 : 0;
140 _Unwind_SetSignalFrame (struct _Unwind_Context
*context
, int val
)
143 context
->flags
|= SIGNAL_FRAME_BIT
;
145 context
->flags
&= ~SIGNAL_FRAME_BIT
;
148 static inline _Unwind_Word
149 _Unwind_IsExtendedContext (struct _Unwind_Context
*context
)
151 return context
->flags
& EXTENDED_CONTEXT_BIT
;
154 /* Get the value of register INDEX as saved in CONTEXT. */
157 _Unwind_GetGR (struct _Unwind_Context
*context
, int index
)
162 #ifdef DWARF_ZERO_REG
163 if (index
== DWARF_ZERO_REG
)
167 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
168 gcc_assert (index
< (int) sizeof(dwarf_reg_size_table
));
169 size
= dwarf_reg_size_table
[index
];
170 ptr
= context
->reg
[index
];
172 if (_Unwind_IsExtendedContext (context
) && context
->by_value
[index
])
173 return (_Unwind_Word
) (_Unwind_Internal_Ptr
) ptr
;
175 /* This will segfault if the register hasn't been saved. */
176 if (size
== sizeof(_Unwind_Ptr
))
177 return * (_Unwind_Ptr
*) ptr
;
180 gcc_assert (size
== sizeof(_Unwind_Word
));
181 return * (_Unwind_Word
*) ptr
;
186 _Unwind_GetPtr (struct _Unwind_Context
*context
, int index
)
188 return (void *)(_Unwind_Ptr
) _Unwind_GetGR (context
, index
);
191 /* Get the value of the CFA as saved in CONTEXT. */
194 _Unwind_GetCFA (struct _Unwind_Context
*context
)
196 return (_Unwind_Ptr
) context
->cfa
;
199 /* Overwrite the saved value for register INDEX in CONTEXT with VAL. */
202 _Unwind_SetGR (struct _Unwind_Context
*context
, int index
, _Unwind_Word val
)
207 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
208 gcc_assert (index
< (int) sizeof(dwarf_reg_size_table
));
209 size
= dwarf_reg_size_table
[index
];
211 if (_Unwind_IsExtendedContext (context
) && context
->by_value
[index
])
213 context
->reg
[index
] = (void *) (_Unwind_Internal_Ptr
) val
;
217 ptr
= context
->reg
[index
];
219 if (size
== sizeof(_Unwind_Ptr
))
220 * (_Unwind_Ptr
*) ptr
= val
;
223 gcc_assert (size
== sizeof(_Unwind_Word
));
224 * (_Unwind_Word
*) ptr
= val
;
228 /* Get the pointer to a register INDEX as saved in CONTEXT. */
231 _Unwind_GetGRPtr (struct _Unwind_Context
*context
, int index
)
233 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
234 if (_Unwind_IsExtendedContext (context
) && context
->by_value
[index
])
235 return &context
->reg
[index
];
236 return context
->reg
[index
];
239 /* Set the pointer to a register INDEX as saved in CONTEXT. */
242 _Unwind_SetGRPtr (struct _Unwind_Context
*context
, int index
, void *p
)
244 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
245 if (_Unwind_IsExtendedContext (context
))
246 context
->by_value
[index
] = 0;
247 context
->reg
[index
] = p
;
250 /* Overwrite the saved value for register INDEX in CONTEXT with VAL. */
253 _Unwind_SetGRValue (struct _Unwind_Context
*context
, int index
,
256 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
257 gcc_assert (index
< (int) sizeof(dwarf_reg_size_table
));
258 gcc_assert (dwarf_reg_size_table
[index
] == sizeof (_Unwind_Ptr
));
260 context
->by_value
[index
] = 1;
261 context
->reg
[index
] = (void *) (_Unwind_Internal_Ptr
) val
;
264 /* Return nonzero if register INDEX is stored by value rather than
268 _Unwind_GRByValue (struct _Unwind_Context
*context
, int index
)
270 index
= DWARF_REG_TO_UNWIND_COLUMN (index
);
271 return context
->by_value
[index
];
274 /* Retrieve the return address for CONTEXT. */
277 _Unwind_GetIP (struct _Unwind_Context
*context
)
279 return (_Unwind_Ptr
) context
->ra
;
282 /* Retrieve the return address and flag whether that IP is before
283 or after first not yet fully executed instruction. */
286 _Unwind_GetIPInfo (struct _Unwind_Context
*context
, int *ip_before_insn
)
288 *ip_before_insn
= _Unwind_IsSignalFrame (context
);
289 return (_Unwind_Ptr
) context
->ra
;
292 /* Overwrite the return address for CONTEXT with VAL. */
295 _Unwind_SetIP (struct _Unwind_Context
*context
, _Unwind_Ptr val
)
297 context
->ra
= (void *) val
;
301 _Unwind_GetLanguageSpecificData (struct _Unwind_Context
*context
)
303 return context
->lsda
;
307 _Unwind_GetRegionStart (struct _Unwind_Context
*context
)
309 return (_Unwind_Ptr
) context
->bases
.func
;
313 _Unwind_FindEnclosingFunction (void *pc
)
315 struct dwarf_eh_bases bases
;
316 const struct dwarf_fde
*fde
= _Unwind_Find_FDE (pc
-1, &bases
);
325 _Unwind_GetDataRelBase (struct _Unwind_Context
*context
)
327 return (_Unwind_Ptr
) context
->bases
.dbase
;
331 _Unwind_GetTextRelBase (struct _Unwind_Context
*context
)
333 return (_Unwind_Ptr
) context
->bases
.tbase
;
337 #ifdef MD_UNWIND_SUPPORT
338 #include MD_UNWIND_SUPPORT
341 /* Extract any interesting information from the CIE for the translation
342 unit F belongs to. Return a pointer to the byte after the augmentation,
343 or NULL if we encountered an undecipherable augmentation. */
345 static const unsigned char *
346 extract_cie_info (const struct dwarf_cie
*cie
, struct _Unwind_Context
*context
,
347 _Unwind_FrameState
*fs
)
349 const unsigned char *aug
= cie
->augmentation
;
350 const unsigned char *p
= aug
+ strlen ((const char *)aug
) + 1;
351 const unsigned char *ret
= NULL
;
355 /* g++ v2 "eh" has pointer immediately following augmentation string,
356 so it must be handled first. */
357 if (aug
[0] == 'e' && aug
[1] == 'h')
359 fs
->eh_ptr
= read_pointer (p
);
360 p
+= sizeof (void *);
364 /* Immediately following the augmentation are the code and
365 data alignment and return address column. */
366 p
= read_uleb128 (p
, &utmp
);
367 fs
->code_align
= (_Unwind_Word
)utmp
;
368 p
= read_sleb128 (p
, &stmp
);
369 fs
->data_align
= (_Unwind_Sword
)stmp
;
370 if (cie
->version
== 1)
371 fs
->retaddr_column
= *p
++;
374 p
= read_uleb128 (p
, &utmp
);
375 fs
->retaddr_column
= (_Unwind_Word
)utmp
;
377 fs
->lsda_encoding
= DW_EH_PE_omit
;
379 /* If the augmentation starts with 'z', then a uleb128 immediately
380 follows containing the length of the augmentation field following
384 p
= read_uleb128 (p
, &utmp
);
391 /* Iterate over recognized augmentation subsequences. */
394 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
397 fs
->lsda_encoding
= *p
++;
401 /* "R" indicates a byte indicating how FDE addresses are encoded. */
402 else if (aug
[0] == 'R')
404 fs
->fde_encoding
= *p
++;
408 /* "P" indicates a personality routine in the CIE augmentation. */
409 else if (aug
[0] == 'P')
411 _Unwind_Ptr personality
;
413 p
= read_encoded_value (context
, *p
, p
+ 1, &personality
);
414 fs
->personality
= (_Unwind_Personality_Fn
) personality
;
418 /* "S" indicates a signal frame. */
419 else if (aug
[0] == 'S')
421 fs
->signal_frame
= 1;
425 /* Otherwise we have an unknown augmentation string.
426 Bail unless we saw a 'z' prefix. */
431 return ret
? ret
: p
;
435 /* Decode a DW_OP stack program. Return the top of stack. Push INITIAL
436 onto the stack to start. */
439 execute_stack_op (const unsigned char *op_ptr
, const unsigned char *op_end
,
440 struct _Unwind_Context
*context
, _Unwind_Word initial
)
442 _Unwind_Word stack
[64]; /* ??? Assume this is enough. */
448 while (op_ptr
< op_end
)
450 enum dwarf_location_atom op
= *op_ptr
++;
452 _uleb128_t reg
, utmp
;
453 _sleb128_t offset
, stmp
;
489 result
= op
- DW_OP_lit0
;
493 result
= (_Unwind_Word
) (_Unwind_Ptr
) read_pointer (op_ptr
);
494 op_ptr
+= sizeof (void *);
497 case DW_OP_GNU_encoded_addr
:
500 op_ptr
= read_encoded_value (context
, *op_ptr
, op_ptr
+1, &presult
);
506 result
= read_1u (op_ptr
);
510 result
= read_1s (op_ptr
);
514 result
= read_2u (op_ptr
);
518 result
= read_2s (op_ptr
);
522 result
= read_4u (op_ptr
);
526 result
= read_4s (op_ptr
);
530 result
= read_8u (op_ptr
);
534 result
= read_8s (op_ptr
);
538 op_ptr
= read_uleb128 (op_ptr
, &utmp
);
539 result
= (_Unwind_Word
)utmp
;
542 op_ptr
= read_sleb128 (op_ptr
, &stmp
);
543 result
= (_Unwind_Sword
)stmp
;
578 result
= _Unwind_GetGR (context
, op
- DW_OP_reg0
);
581 op_ptr
= read_uleb128 (op_ptr
, ®
);
582 result
= _Unwind_GetGR (context
, reg
);
617 op_ptr
= read_sleb128 (op_ptr
, &offset
);
618 result
= _Unwind_GetGR (context
, op
- DW_OP_breg0
) + offset
;
621 op_ptr
= read_uleb128 (op_ptr
, ®
);
622 op_ptr
= read_sleb128 (op_ptr
, &offset
);
623 result
= _Unwind_GetGR (context
, reg
) + (_Unwind_Word
)offset
;
627 gcc_assert (stack_elt
);
628 result
= stack
[stack_elt
- 1];
632 gcc_assert (stack_elt
);
638 gcc_assert (offset
< stack_elt
- 1);
639 result
= stack
[stack_elt
- 1 - offset
];
643 gcc_assert (stack_elt
>= 2);
644 result
= stack
[stack_elt
- 2];
650 gcc_assert (stack_elt
>= 2);
651 t
= stack
[stack_elt
- 1];
652 stack
[stack_elt
- 1] = stack
[stack_elt
- 2];
653 stack
[stack_elt
- 2] = t
;
659 _Unwind_Word t1
, t2
, t3
;
661 gcc_assert (stack_elt
>= 3);
662 t1
= stack
[stack_elt
- 1];
663 t2
= stack
[stack_elt
- 2];
664 t3
= stack
[stack_elt
- 3];
665 stack
[stack_elt
- 1] = t2
;
666 stack
[stack_elt
- 2] = t3
;
667 stack
[stack_elt
- 3] = t1
;
672 case DW_OP_deref_size
:
676 case DW_OP_plus_uconst
:
677 /* Unary operations. */
678 gcc_assert (stack_elt
);
681 result
= stack
[stack_elt
];
687 void *ptr
= (void *) (_Unwind_Ptr
) result
;
688 result
= (_Unwind_Ptr
) read_pointer (ptr
);
692 case DW_OP_deref_size
:
694 void *ptr
= (void *) (_Unwind_Ptr
) result
;
698 result
= read_1u (ptr
);
701 result
= read_2u (ptr
);
704 result
= read_4u (ptr
);
707 result
= read_8u (ptr
);
716 if ((_Unwind_Sword
) result
< 0)
725 case DW_OP_plus_uconst
:
726 op_ptr
= read_uleb128 (op_ptr
, &utmp
);
727 result
+= (_Unwind_Word
)utmp
;
753 /* Binary operations. */
754 _Unwind_Word first
, second
;
755 gcc_assert (stack_elt
>= 2);
758 second
= stack
[stack_elt
];
759 first
= stack
[stack_elt
+ 1];
764 result
= second
& first
;
767 result
= (_Unwind_Sword
) second
/ (_Unwind_Sword
) first
;
770 result
= second
- first
;
773 result
= (_Unwind_Sword
) second
% (_Unwind_Sword
) first
;
776 result
= second
* first
;
779 result
= second
| first
;
782 result
= second
+ first
;
785 result
= second
<< first
;
788 result
= second
>> first
;
791 result
= (_Unwind_Sword
) second
>> first
;
794 result
= second
^ first
;
797 result
= (_Unwind_Sword
) first
<= (_Unwind_Sword
) second
;
800 result
= (_Unwind_Sword
) first
>= (_Unwind_Sword
) second
;
803 result
= (_Unwind_Sword
) first
== (_Unwind_Sword
) second
;
806 result
= (_Unwind_Sword
) first
< (_Unwind_Sword
) second
;
809 result
= (_Unwind_Sword
) first
> (_Unwind_Sword
) second
;
812 result
= (_Unwind_Sword
) first
!= (_Unwind_Sword
) second
;
822 offset
= read_2s (op_ptr
);
828 gcc_assert (stack_elt
);
831 offset
= read_2s (op_ptr
);
833 if (stack
[stack_elt
] != 0)
844 /* Most things push a result value. */
845 gcc_assert ((size_t) stack_elt
< sizeof(stack
)/sizeof(*stack
));
846 stack
[stack_elt
++] = result
;
850 /* We were executing this program to get a value. It should be
852 gcc_assert (stack_elt
);
854 return stack
[stack_elt
];
858 /* Decode DWARF 2 call frame information. Takes pointers the
859 instruction sequence to decode, current register information and
860 CIE info, and the PC range to evaluate. */
863 execute_cfa_program (const unsigned char *insn_ptr
,
864 const unsigned char *insn_end
,
865 struct _Unwind_Context
*context
,
866 _Unwind_FrameState
*fs
)
868 struct frame_state_reg_info
*unused_rs
= NULL
;
870 /* Don't allow remember/restore between CIE and FDE programs. */
871 fs
->regs
.prev
= NULL
;
873 /* The comparison with the return address uses < rather than <= because
874 we are only interested in the effects of code before the call; for a
875 noreturn function, the return address may point to unrelated code with
876 a different stack configuration that we are not interested in. We
877 assume that the call itself is unwind info-neutral; if not, or if
878 there are delay instructions that adjust the stack, these must be
879 reflected at the point immediately before the call insn.
880 In signal frames, return address is after last completed instruction,
881 so we add 1 to return address to make the comparison <=. */
882 while (insn_ptr
< insn_end
883 && fs
->pc
< context
->ra
+ _Unwind_IsSignalFrame (context
))
885 unsigned char insn
= *insn_ptr
++;
886 _uleb128_t reg
, utmp
;
887 _sleb128_t offset
, stmp
;
889 if ((insn
& 0xc0) == DW_CFA_advance_loc
)
890 fs
->pc
+= (insn
& 0x3f) * fs
->code_align
;
891 else if ((insn
& 0xc0) == DW_CFA_offset
)
894 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
895 offset
= (_Unwind_Sword
) utmp
* fs
->data_align
;
896 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
898 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= offset
;
900 else if ((insn
& 0xc0) == DW_CFA_restore
)
903 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
= REG_UNSAVED
;
911 insn_ptr
= read_encoded_value (context
, fs
->fde_encoding
,
913 fs
->pc
= (void *) pc
;
917 case DW_CFA_advance_loc1
:
918 fs
->pc
+= read_1u (insn_ptr
) * fs
->code_align
;
921 case DW_CFA_advance_loc2
:
922 fs
->pc
+= read_2u (insn_ptr
) * fs
->code_align
;
925 case DW_CFA_advance_loc4
:
926 fs
->pc
+= read_4u (insn_ptr
) * fs
->code_align
;
930 case DW_CFA_offset_extended
:
931 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
932 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
933 offset
= (_Unwind_Sword
) utmp
* fs
->data_align
;
934 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
936 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= offset
;
939 case DW_CFA_restore_extended
:
940 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
941 /* FIXME, this is wrong; the CIE might have said that the
942 register was saved somewhere. */
943 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN(reg
)].how
= REG_UNSAVED
;
946 case DW_CFA_undefined
:
947 case DW_CFA_same_value
:
948 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
949 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN(reg
)].how
= REG_UNSAVED
;
955 case DW_CFA_register
:
958 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
959 insn_ptr
= read_uleb128 (insn_ptr
, ®2
);
960 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
= REG_SAVED_REG
;
961 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.reg
=
966 case DW_CFA_remember_state
:
968 struct frame_state_reg_info
*new_rs
;
972 unused_rs
= unused_rs
->prev
;
975 new_rs
= alloca (sizeof (struct frame_state_reg_info
));
978 fs
->regs
.prev
= new_rs
;
982 case DW_CFA_restore_state
:
984 struct frame_state_reg_info
*old_rs
= fs
->regs
.prev
;
986 old_rs
->prev
= unused_rs
;
992 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
993 fs
->regs
.cfa_reg
= (_Unwind_Word
)utmp
;
994 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
995 fs
->regs
.cfa_offset
= (_Unwind_Word
)utmp
;
996 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
999 case DW_CFA_def_cfa_register
:
1000 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1001 fs
->regs
.cfa_reg
= (_Unwind_Word
)utmp
;
1002 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
1005 case DW_CFA_def_cfa_offset
:
1006 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1007 fs
->regs
.cfa_offset
= utmp
;
1008 /* cfa_how deliberately not set. */
1011 case DW_CFA_def_cfa_expression
:
1012 fs
->regs
.cfa_exp
= insn_ptr
;
1013 fs
->regs
.cfa_how
= CFA_EXP
;
1014 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1018 case DW_CFA_expression
:
1019 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
1020 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
= REG_SAVED_EXP
;
1021 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.exp
= insn_ptr
;
1022 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1027 case DW_CFA_offset_extended_sf
:
1028 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
1029 insn_ptr
= read_sleb128 (insn_ptr
, &stmp
);
1030 offset
= stmp
* fs
->data_align
;
1031 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
1033 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= offset
;
1036 case DW_CFA_def_cfa_sf
:
1037 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1038 fs
->regs
.cfa_reg
= (_Unwind_Word
)utmp
;
1039 insn_ptr
= read_sleb128 (insn_ptr
, &stmp
);
1040 fs
->regs
.cfa_offset
= (_Unwind_Sword
)stmp
;
1041 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
1042 fs
->regs
.cfa_offset
*= fs
->data_align
;
1045 case DW_CFA_def_cfa_offset_sf
:
1046 insn_ptr
= read_sleb128 (insn_ptr
, &stmp
);
1047 fs
->regs
.cfa_offset
= (_Unwind_Sword
)stmp
;
1048 fs
->regs
.cfa_offset
*= fs
->data_align
;
1049 /* cfa_how deliberately not set. */
1052 case DW_CFA_val_offset
:
1053 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
1054 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1055 offset
= (_Unwind_Sword
) utmp
* fs
->data_align
;
1056 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
1057 = REG_SAVED_VAL_OFFSET
;
1058 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= offset
;
1061 case DW_CFA_val_offset_sf
:
1062 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
1063 insn_ptr
= read_sleb128 (insn_ptr
, &stmp
);
1064 offset
= stmp
* fs
->data_align
;
1065 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
1066 = REG_SAVED_VAL_OFFSET
;
1067 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= offset
;
1070 case DW_CFA_val_expression
:
1071 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
1072 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
1073 = REG_SAVED_VAL_EXP
;
1074 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.exp
= insn_ptr
;
1075 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1079 case DW_CFA_GNU_window_save
:
1080 /* ??? Hardcoded for SPARC register window configuration. */
1081 for (reg
= 16; reg
< 32; ++reg
)
1083 fs
->regs
.reg
[reg
].how
= REG_SAVED_OFFSET
;
1084 fs
->regs
.reg
[reg
].loc
.offset
= (reg
- 16) * sizeof (void *);
1088 case DW_CFA_GNU_args_size
:
1089 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1090 context
->args_size
= (_Unwind_Word
)utmp
;
1093 case DW_CFA_GNU_negative_offset_extended
:
1094 /* Obsoleted by DW_CFA_offset_extended_sf, but used by
1095 older PowerPC code. */
1096 insn_ptr
= read_uleb128 (insn_ptr
, ®
);
1097 insn_ptr
= read_uleb128 (insn_ptr
, &utmp
);
1098 offset
= (_Unwind_Word
) utmp
* fs
->data_align
;
1099 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].how
1101 fs
->regs
.reg
[DWARF_REG_TO_UNWIND_COLUMN (reg
)].loc
.offset
= -offset
;
1110 /* Given the _Unwind_Context CONTEXT for a stack frame, look up the FDE for
1111 its caller and decode it into FS. This function also sets the
1112 args_size and lsda members of CONTEXT, as they are really information
1113 about the caller's frame. */
1115 static _Unwind_Reason_Code
1116 uw_frame_state_for (struct _Unwind_Context
*context
, _Unwind_FrameState
*fs
)
1118 const struct dwarf_fde
*fde
;
1119 const struct dwarf_cie
*cie
;
1120 const unsigned char *aug
, *insn
, *end
;
1122 memset (fs
, 0, sizeof (*fs
));
1123 context
->args_size
= 0;
1126 if (context
->ra
== 0)
1127 return _URC_END_OF_STACK
;
1129 fde
= _Unwind_Find_FDE (context
->ra
+ _Unwind_IsSignalFrame (context
) - 1,
1133 #ifdef MD_FALLBACK_FRAME_STATE_FOR
1134 /* Couldn't find frame unwind info for this function. Try a
1135 target-specific fallback mechanism. This will necessarily
1136 not provide a personality routine or LSDA. */
1137 return MD_FALLBACK_FRAME_STATE_FOR (context
, fs
);
1139 return _URC_END_OF_STACK
;
1143 fs
->pc
= context
->bases
.func
;
1145 cie
= get_cie (fde
);
1146 insn
= extract_cie_info (cie
, context
, fs
);
1148 /* CIE contained unknown augmentation. */
1149 return _URC_FATAL_PHASE1_ERROR
;
1151 /* First decode all the insns in the CIE. */
1152 end
= (const unsigned char *) next_fde ((const struct dwarf_fde
*) cie
);
1153 execute_cfa_program (insn
, end
, context
, fs
);
1155 /* Locate augmentation for the fde. */
1156 aug
= (const unsigned char *) fde
+ sizeof (*fde
);
1157 aug
+= 2 * size_of_encoded_value (fs
->fde_encoding
);
1162 aug
= read_uleb128 (aug
, &i
);
1165 if (fs
->lsda_encoding
!= DW_EH_PE_omit
)
1169 aug
= read_encoded_value (context
, fs
->lsda_encoding
, aug
, &lsda
);
1170 context
->lsda
= (void *) lsda
;
1173 /* Then the insns in the FDE up to our target PC. */
1176 end
= (const unsigned char *) next_fde (fde
);
1177 execute_cfa_program (insn
, end
, context
, fs
);
1179 return _URC_NO_REASON
;
1182 typedef struct frame_state
1188 long reg_or_offset
[PRE_GCC3_DWARF_FRAME_REGISTERS
+1];
1189 unsigned short cfa_reg
;
1190 unsigned short retaddr_column
;
1191 char saved
[PRE_GCC3_DWARF_FRAME_REGISTERS
+1];
1194 struct frame_state
* __frame_state_for (void *, struct frame_state
*);
1196 /* Called from pre-G++ 3.0 __throw to find the registers to restore for
1197 a given PC_TARGET. The caller should allocate a local variable of
1198 `struct frame_state' and pass its address to STATE_IN. */
1200 struct frame_state
*
1201 __frame_state_for (void *pc_target
, struct frame_state
*state_in
)
1203 struct _Unwind_Context context
;
1204 _Unwind_FrameState fs
;
1207 memset (&context
, 0, sizeof (struct _Unwind_Context
));
1208 context
.flags
= EXTENDED_CONTEXT_BIT
;
1209 context
.ra
= pc_target
+ 1;
1211 if (uw_frame_state_for (&context
, &fs
) != _URC_NO_REASON
)
1214 /* We have no way to pass a location expression for the CFA to our
1215 caller. It wouldn't understand it anyway. */
1216 if (fs
.regs
.cfa_how
== CFA_EXP
)
1219 for (reg
= 0; reg
< PRE_GCC3_DWARF_FRAME_REGISTERS
+ 1; reg
++)
1221 state_in
->saved
[reg
] = fs
.regs
.reg
[reg
].how
;
1222 switch (state_in
->saved
[reg
])
1225 state_in
->reg_or_offset
[reg
] = fs
.regs
.reg
[reg
].loc
.reg
;
1227 case REG_SAVED_OFFSET
:
1228 state_in
->reg_or_offset
[reg
] = fs
.regs
.reg
[reg
].loc
.offset
;
1231 state_in
->reg_or_offset
[reg
] = 0;
1236 state_in
->cfa_offset
= fs
.regs
.cfa_offset
;
1237 state_in
->cfa_reg
= fs
.regs
.cfa_reg
;
1238 state_in
->retaddr_column
= fs
.retaddr_column
;
1239 state_in
->args_size
= context
.args_size
;
1240 state_in
->eh_ptr
= fs
.eh_ptr
;
1245 typedef union { _Unwind_Ptr ptr
; _Unwind_Word word
; } _Unwind_SpTmp
;
1248 _Unwind_SetSpColumn (struct _Unwind_Context
*context
, void *cfa
,
1249 _Unwind_SpTmp
*tmp_sp
)
1251 int size
= dwarf_reg_size_table
[__builtin_dwarf_sp_column ()];
1253 if (size
== sizeof(_Unwind_Ptr
))
1254 tmp_sp
->ptr
= (_Unwind_Ptr
) cfa
;
1257 gcc_assert (size
== sizeof(_Unwind_Word
));
1258 tmp_sp
->word
= (_Unwind_Ptr
) cfa
;
1260 _Unwind_SetGRPtr (context
, __builtin_dwarf_sp_column (), tmp_sp
);
1264 uw_update_context_1 (struct _Unwind_Context
*context
, _Unwind_FrameState
*fs
)
1266 struct _Unwind_Context orig_context
= *context
;
1270 #ifdef EH_RETURN_STACKADJ_RTX
1271 /* Special handling here: Many machines do not use a frame pointer,
1272 and track the CFA only through offsets from the stack pointer from
1273 one frame to the next. In this case, the stack pointer is never
1274 stored, so it has no saved address in the context. What we do
1275 have is the CFA from the previous stack frame.
1277 In very special situations (such as unwind info for signal return),
1278 there may be location expressions that use the stack pointer as well.
1280 Do this conditionally for one frame. This allows the unwind info
1281 for one frame to save a copy of the stack pointer from the previous
1282 frame, and be able to use much easier CFA mechanisms to do it.
1283 Always zap the saved stack pointer value for the next frame; carrying
1284 the value over from one frame to another doesn't make sense. */
1286 _Unwind_SpTmp tmp_sp
;
1288 if (!_Unwind_GetGRPtr (&orig_context
, __builtin_dwarf_sp_column ()))
1289 _Unwind_SetSpColumn (&orig_context
, context
->cfa
, &tmp_sp
);
1290 _Unwind_SetGRPtr (context
, __builtin_dwarf_sp_column (), NULL
);
1293 /* Compute this frame's CFA. */
1294 switch (fs
->regs
.cfa_how
)
1296 case CFA_REG_OFFSET
:
1297 cfa
= _Unwind_GetPtr (&orig_context
, fs
->regs
.cfa_reg
);
1298 cfa
+= fs
->regs
.cfa_offset
;
1303 const unsigned char *exp
= fs
->regs
.cfa_exp
;
1306 exp
= read_uleb128 (exp
, &len
);
1307 cfa
= (void *) (_Unwind_Ptr
)
1308 execute_stack_op (exp
, exp
+ len
, &orig_context
, 0);
1317 /* Compute the addresses of all registers saved in this frame. */
1318 for (i
= 0; i
< DWARF_FRAME_REGISTERS
+ 1; ++i
)
1319 switch (fs
->regs
.reg
[i
].how
)
1324 case REG_SAVED_OFFSET
:
1325 _Unwind_SetGRPtr (context
, i
,
1326 (void *) (cfa
+ fs
->regs
.reg
[i
].loc
.offset
));
1330 if (_Unwind_GRByValue (&orig_context
, fs
->regs
.reg
[i
].loc
.reg
))
1331 _Unwind_SetGRValue (context
, i
,
1332 _Unwind_GetGR (&orig_context
,
1333 fs
->regs
.reg
[i
].loc
.reg
));
1335 _Unwind_SetGRPtr (context
, i
,
1336 _Unwind_GetGRPtr (&orig_context
,
1337 fs
->regs
.reg
[i
].loc
.reg
));
1342 const unsigned char *exp
= fs
->regs
.reg
[i
].loc
.exp
;
1346 exp
= read_uleb128 (exp
, &len
);
1347 val
= execute_stack_op (exp
, exp
+ len
, &orig_context
,
1349 _Unwind_SetGRPtr (context
, i
, (void *) val
);
1353 case REG_SAVED_VAL_OFFSET
:
1354 _Unwind_SetGRValue (context
, i
,
1355 (_Unwind_Internal_Ptr
)
1356 (cfa
+ fs
->regs
.reg
[i
].loc
.offset
));
1359 case REG_SAVED_VAL_EXP
:
1361 const unsigned char *exp
= fs
->regs
.reg
[i
].loc
.exp
;
1365 exp
= read_uleb128 (exp
, &len
);
1366 val
= execute_stack_op (exp
, exp
+ len
, &orig_context
,
1368 _Unwind_SetGRValue (context
, i
, val
);
1373 _Unwind_SetSignalFrame (context
, fs
->signal_frame
);
1375 #ifdef MD_FROB_UPDATE_CONTEXT
1376 MD_FROB_UPDATE_CONTEXT (context
, fs
);
1380 /* CONTEXT describes the unwind state for a frame, and FS describes the FDE
1381 of its caller. Update CONTEXT to refer to the caller as well. Note
1382 that the args_size and lsda members are not updated here, but later in
1383 uw_frame_state_for. */
1386 uw_update_context (struct _Unwind_Context
*context
, _Unwind_FrameState
*fs
)
1388 uw_update_context_1 (context
, fs
);
1390 /* Compute the return address now, since the return address column
1391 can change from frame to frame. */
1392 context
->ra
= __builtin_extract_return_addr
1393 (_Unwind_GetPtr (context
, fs
->retaddr_column
));
1397 uw_advance_context (struct _Unwind_Context
*context
, _Unwind_FrameState
*fs
)
1399 uw_update_context (context
, fs
);
1402 /* Fill in CONTEXT for top-of-stack. The only valid registers at this
1403 level will be the return address and the CFA. */
1405 #define uw_init_context(CONTEXT) \
1408 /* Do any necessary initialization to access arbitrary stack frames. \
1409 On the SPARC, this means flushing the register windows. */ \
1410 __builtin_unwind_init (); \
1411 uw_init_context_1 (CONTEXT, __builtin_dwarf_cfa (), \
1412 __builtin_return_address (0)); \
1417 init_dwarf_reg_size_table (void)
1419 __builtin_init_dwarf_reg_size_table (dwarf_reg_size_table
);
1423 uw_init_context_1 (struct _Unwind_Context
*context
,
1424 void *outer_cfa
, void *outer_ra
)
1426 void *ra
= __builtin_extract_return_addr (__builtin_return_address (0));
1427 _Unwind_FrameState fs
;
1428 _Unwind_SpTmp sp_slot
;
1429 _Unwind_Reason_Code code
;
1431 memset (context
, 0, sizeof (struct _Unwind_Context
));
1433 context
->flags
= EXTENDED_CONTEXT_BIT
;
1435 code
= uw_frame_state_for (context
, &fs
);
1436 gcc_assert (code
== _URC_NO_REASON
);
1440 static __gthread_once_t once_regsizes
= __GTHREAD_ONCE_INIT
;
1441 if (__gthread_once (&once_regsizes
, init_dwarf_reg_size_table
) != 0
1442 && dwarf_reg_size_table
[0] == 0)
1443 init_dwarf_reg_size_table ();
1446 if (dwarf_reg_size_table
[0] == 0)
1447 init_dwarf_reg_size_table ();
1450 /* Force the frame state to use the known cfa value. */
1451 _Unwind_SetSpColumn (context
, outer_cfa
, &sp_slot
);
1452 fs
.regs
.cfa_how
= CFA_REG_OFFSET
;
1453 fs
.regs
.cfa_reg
= __builtin_dwarf_sp_column ();
1454 fs
.regs
.cfa_offset
= 0;
1456 uw_update_context_1 (context
, &fs
);
1458 /* If the return address column was saved in a register in the
1459 initialization context, then we can't see it in the given
1460 call frame data. So have the initialization context tell us. */
1461 context
->ra
= __builtin_extract_return_addr (outer_ra
);
1465 /* Install TARGET into CURRENT so that we can return to it. This is a
1466 macro because __builtin_eh_return must be invoked in the context of
1469 #define uw_install_context(CURRENT, TARGET) \
1472 long offset = uw_install_context_1 ((CURRENT), (TARGET)); \
1473 void *handler = __builtin_frob_return_addr ((TARGET)->ra); \
1474 __builtin_eh_return (offset, handler); \
1479 uw_install_context_1 (struct _Unwind_Context
*current
,
1480 struct _Unwind_Context
*target
)
1483 _Unwind_SpTmp sp_slot
;
1485 /* If the target frame does not have a saved stack pointer,
1486 then set up the target's CFA. */
1487 if (!_Unwind_GetGRPtr (target
, __builtin_dwarf_sp_column ()))
1488 _Unwind_SetSpColumn (target
, target
->cfa
, &sp_slot
);
1490 for (i
= 0; i
< DWARF_FRAME_REGISTERS
; ++i
)
1492 void *c
= current
->reg
[i
];
1493 void *t
= target
->reg
[i
];
1495 gcc_assert (current
->by_value
[i
] == 0);
1496 if (target
->by_value
[i
] && c
)
1500 if (dwarf_reg_size_table
[i
] == sizeof (_Unwind_Word
))
1502 w
= (_Unwind_Internal_Ptr
) t
;
1503 memcpy (c
, &w
, sizeof (_Unwind_Word
));
1507 gcc_assert (dwarf_reg_size_table
[i
] == sizeof (_Unwind_Ptr
));
1508 p
= (_Unwind_Internal_Ptr
) t
;
1509 memcpy (c
, &p
, sizeof (_Unwind_Ptr
));
1512 else if (t
&& c
&& t
!= c
)
1513 memcpy (c
, t
, dwarf_reg_size_table
[i
]);
1516 /* If the current frame doesn't have a saved stack pointer, then we
1517 need to rely on EH_RETURN_STACKADJ_RTX to get our target stack
1518 pointer value reloaded. */
1519 if (!_Unwind_GetGRPtr (current
, __builtin_dwarf_sp_column ()))
1523 target_cfa
= _Unwind_GetPtr (target
, __builtin_dwarf_sp_column ());
1525 /* We adjust SP by the difference between CURRENT and TARGET's CFA. */
1526 if (STACK_GROWS_DOWNWARD
)
1527 return target_cfa
- current
->cfa
+ target
->args_size
;
1529 return current
->cfa
- target_cfa
- target
->args_size
;
1534 static inline _Unwind_Ptr
1535 uw_identify_context (struct _Unwind_Context
*context
)
1537 return _Unwind_GetCFA (context
);
1541 #include "unwind.inc"
1543 #if defined (USE_GAS_SYMVER) && defined (SHARED) && defined (USE_LIBUNWIND_EXCEPTIONS)
1544 alias (_Unwind_Backtrace
);
1545 alias (_Unwind_DeleteException
);
1546 alias (_Unwind_FindEnclosingFunction
);
1547 alias (_Unwind_ForcedUnwind
);
1548 alias (_Unwind_GetDataRelBase
);
1549 alias (_Unwind_GetTextRelBase
);
1550 alias (_Unwind_GetCFA
);
1551 alias (_Unwind_GetGR
);
1552 alias (_Unwind_GetIP
);
1553 alias (_Unwind_GetLanguageSpecificData
);
1554 alias (_Unwind_GetRegionStart
);
1555 alias (_Unwind_RaiseException
);
1556 alias (_Unwind_Resume
);
1557 alias (_Unwind_Resume_or_Rethrow
);
1558 alias (_Unwind_SetGR
);
1559 alias (_Unwind_SetIP
);
1562 #endif /* !USING_SJLJ_EXCEPTIONS */