1 /* DWARF2 exception handling and frame unwind runtime interface routines.
2 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
3 2008, 2009, 2010, 2011 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 3, or (at your option)
12 GCC is distributed in the hope that it will be useful, but WITHOUT
13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
15 License for more details.
17 Under Section 7 of GPL version 3, you are granted additional
18 permissions described in the GCC Runtime Library Exception, version
19 3.1, as published by the Free Software Foundation.
21 You should have received a copy of the GNU General Public License and
22 a copy of the GCC Runtime Library Exception along with this program;
23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 <http://www.gnu.org/licenses/>. */
28 #include "coretypes.h"
32 #ifdef __USING_SJLJ_EXCEPTIONS__
33 # define NO_SIZE_OF_ENCODED_VALUE
35 #include "unwind-pe.h"
36 #include "unwind-dw2-fde.h"
38 #include "unwind-dw2.h"
44 #ifndef __USING_SJLJ_EXCEPTIONS__
46 #ifndef STACK_GROWS_DOWNWARD
47 #define STACK_GROWS_DOWNWARD 0
49 #undef STACK_GROWS_DOWNWARD
50 #define STACK_GROWS_DOWNWARD 1
53 /* Dwarf frame registers used for pre gcc 3.0 compiled glibc. */
54 #ifndef PRE_GCC3_DWARF_FRAME_REGISTERS
55 #define PRE_GCC3_DWARF_FRAME_REGISTERS DWARF_FRAME_REGISTERS
58 #ifndef DWARF_REG_TO_UNWIND_COLUMN
59 #define DWARF_REG_TO_UNWIND_COLUMN(REGNO) (REGNO)
62 #ifdef REG_VALUE_IN_UNWIND_CONTEXT
63 typedef _Unwind_Word _Unwind_Context_Reg_Val;
65 #ifndef ASSUME_EXTENDED_UNWIND_CONTEXT
66 #define ASSUME_EXTENDED_UNWIND_CONTEXT 1
69 static inline _Unwind_Word
70 _Unwind_Get_Unwind_Word (_Unwind_Context_Reg_Val val)
75 static inline _Unwind_Context_Reg_Val
76 _Unwind_Get_Unwind_Context_Reg_Val (_Unwind_Word val)
81 typedef void *_Unwind_Context_Reg_Val;
83 static inline _Unwind_Word
84 _Unwind_Get_Unwind_Word (_Unwind_Context_Reg_Val val)
86 return (_Unwind_Word) (_Unwind_Internal_Ptr) val;
89 static inline _Unwind_Context_Reg_Val
90 _Unwind_Get_Unwind_Context_Reg_Val (_Unwind_Word val)
92 return (_Unwind_Context_Reg_Val) (_Unwind_Internal_Ptr) val;
96 #ifndef ASSUME_EXTENDED_UNWIND_CONTEXT
97 #define ASSUME_EXTENDED_UNWIND_CONTEXT 0
100 /* This is the register and unwind state for a particular frame. This
101 provides the information necessary to unwind up past a frame and return
103 struct _Unwind_Context
105 _Unwind_Context_Reg_Val reg[DWARF_FRAME_REGISTERS+1];
109 struct dwarf_eh_bases bases;
110 /* Signal frame context. */
111 #define SIGNAL_FRAME_BIT ((~(_Unwind_Word) 0 >> 1) + 1)
112 /* Context which has version/args_size/by_value fields. */
113 #define EXTENDED_CONTEXT_BIT ((~(_Unwind_Word) 0 >> 2) + 1)
115 /* 0 for now, can be increased when further fields are added to
116 struct _Unwind_Context. */
117 _Unwind_Word version;
118 _Unwind_Word args_size;
119 char by_value[DWARF_FRAME_REGISTERS+1];
122 /* Byte size of every register managed by these routines. */
123 static unsigned char dwarf_reg_size_table[DWARF_FRAME_REGISTERS+1];
126 /* Read unaligned data from the instruction buffer. */
131 unsigned u2 __attribute__ ((mode (HI)));
132 unsigned u4 __attribute__ ((mode (SI)));
133 unsigned u8 __attribute__ ((mode (DI)));
134 signed s2 __attribute__ ((mode (HI)));
135 signed s4 __attribute__ ((mode (SI)));
136 signed s8 __attribute__ ((mode (DI)));
137 } __attribute__ ((packed));
139 static void uw_update_context (struct _Unwind_Context *, _Unwind_FrameState *);
140 static _Unwind_Reason_Code uw_frame_state_for (struct _Unwind_Context *,
141 _Unwind_FrameState *);
144 read_pointer (const void *p) { const union unaligned *up = p; return up->p; }
147 read_1u (const void *p) { return *(const unsigned char *) p; }
150 read_1s (const void *p) { return *(const signed char *) p; }
153 read_2u (const void *p) { const union unaligned *up = p; return up->u2; }
156 read_2s (const void *p) { const union unaligned *up = p; return up->s2; }
158 static inline unsigned int
159 read_4u (const void *p) { const union unaligned *up = p; return up->u4; }
162 read_4s (const void *p) { const union unaligned *up = p; return up->s4; }
164 static inline unsigned long
165 read_8u (const void *p) { const union unaligned *up = p; return up->u8; }
167 static inline unsigned long
168 read_8s (const void *p) { const union unaligned *up = p; return up->s8; }
170 static inline _Unwind_Word
171 _Unwind_IsSignalFrame (struct _Unwind_Context *context)
173 return (context->flags & SIGNAL_FRAME_BIT) ? 1 : 0;
177 _Unwind_SetSignalFrame (struct _Unwind_Context *context, int val)
180 context->flags |= SIGNAL_FRAME_BIT;
182 context->flags &= ~SIGNAL_FRAME_BIT;
185 static inline _Unwind_Word
186 _Unwind_IsExtendedContext (struct _Unwind_Context *context)
188 return (ASSUME_EXTENDED_UNWIND_CONTEXT
189 || (context->flags & EXTENDED_CONTEXT_BIT));
192 /* Get the value of register INDEX as saved in CONTEXT. */
195 _Unwind_GetGR (struct _Unwind_Context *context, int index)
198 _Unwind_Context_Reg_Val val;
200 #ifdef DWARF_ZERO_REG
201 if (index == DWARF_ZERO_REG)
205 index = DWARF_REG_TO_UNWIND_COLUMN (index);
206 gcc_assert (index < (int) sizeof(dwarf_reg_size_table));
207 size = dwarf_reg_size_table[index];
208 val = context->reg[index];
210 if (_Unwind_IsExtendedContext (context) && context->by_value[index])
211 return _Unwind_Get_Unwind_Word (val);
213 /* This will segfault if the register hasn't been saved. */
214 if (size == sizeof(_Unwind_Ptr))
215 return * (_Unwind_Ptr *) (_Unwind_Internal_Ptr) val;
218 gcc_assert (size == sizeof(_Unwind_Word));
219 return * (_Unwind_Word *) (_Unwind_Internal_Ptr) val;
224 _Unwind_GetPtr (struct _Unwind_Context *context, int index)
226 return (void *)(_Unwind_Ptr) _Unwind_GetGR (context, index);
229 /* Get the value of the CFA as saved in CONTEXT. */
232 _Unwind_GetCFA (struct _Unwind_Context *context)
234 return (_Unwind_Ptr) context->cfa;
237 /* Overwrite the saved value for register INDEX in CONTEXT with VAL. */
240 _Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val)
245 index = DWARF_REG_TO_UNWIND_COLUMN (index);
246 gcc_assert (index < (int) sizeof(dwarf_reg_size_table));
247 size = dwarf_reg_size_table[index];
249 if (_Unwind_IsExtendedContext (context) && context->by_value[index])
251 context->reg[index] = _Unwind_Get_Unwind_Context_Reg_Val (val);
255 ptr = (void *) (_Unwind_Internal_Ptr) context->reg[index];
257 if (size == sizeof(_Unwind_Ptr))
258 * (_Unwind_Ptr *) ptr = val;
261 gcc_assert (size == sizeof(_Unwind_Word));
262 * (_Unwind_Word *) ptr = val;
266 /* Get the pointer to a register INDEX as saved in CONTEXT. */
269 _Unwind_GetGRPtr (struct _Unwind_Context *context, int index)
271 index = DWARF_REG_TO_UNWIND_COLUMN (index);
272 if (_Unwind_IsExtendedContext (context) && context->by_value[index])
273 return &context->reg[index];
274 return (void *) (_Unwind_Internal_Ptr) context->reg[index];
277 /* Set the pointer to a register INDEX as saved in CONTEXT. */
280 _Unwind_SetGRPtr (struct _Unwind_Context *context, int index, void *p)
282 index = DWARF_REG_TO_UNWIND_COLUMN (index);
283 if (_Unwind_IsExtendedContext (context))
284 context->by_value[index] = 0;
285 context->reg[index] = (_Unwind_Context_Reg_Val) (_Unwind_Internal_Ptr) p;
288 /* Overwrite the saved value for register INDEX in CONTEXT with VAL. */
291 _Unwind_SetGRValue (struct _Unwind_Context *context, int index,
294 index = DWARF_REG_TO_UNWIND_COLUMN (index);
295 gcc_assert (index < (int) sizeof(dwarf_reg_size_table));
296 gcc_assert (dwarf_reg_size_table[index] == sizeof (_Unwind_Context_Reg_Val));
298 context->by_value[index] = 1;
299 context->reg[index] = _Unwind_Get_Unwind_Context_Reg_Val (val);
302 /* Return nonzero if register INDEX is stored by value rather than
306 _Unwind_GRByValue (struct _Unwind_Context *context, int index)
308 index = DWARF_REG_TO_UNWIND_COLUMN (index);
309 return context->by_value[index];
312 /* Retrieve the return address for CONTEXT. */
315 _Unwind_GetIP (struct _Unwind_Context *context)
317 return (_Unwind_Ptr) context->ra;
320 /* Retrieve the return address and flag whether that IP is before
321 or after first not yet fully executed instruction. */
324 _Unwind_GetIPInfo (struct _Unwind_Context *context, int *ip_before_insn)
326 *ip_before_insn = _Unwind_IsSignalFrame (context);
327 return (_Unwind_Ptr) context->ra;
330 /* Overwrite the return address for CONTEXT with VAL. */
333 _Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val)
335 context->ra = (void *) val;
339 _Unwind_GetLanguageSpecificData (struct _Unwind_Context *context)
341 return context->lsda;
345 _Unwind_GetRegionStart (struct _Unwind_Context *context)
347 return (_Unwind_Ptr) context->bases.func;
351 _Unwind_FindEnclosingFunction (void *pc)
353 struct dwarf_eh_bases bases;
354 const struct dwarf_fde *fde = _Unwind_Find_FDE (pc-1, &bases);
363 _Unwind_GetDataRelBase (struct _Unwind_Context *context)
365 return (_Unwind_Ptr) context->bases.dbase;
369 _Unwind_GetTextRelBase (struct _Unwind_Context *context)
371 return (_Unwind_Ptr) context->bases.tbase;
375 #include "md-unwind-support.h"
377 /* Extract any interesting information from the CIE for the translation
378 unit F belongs to. Return a pointer to the byte after the augmentation,
379 or NULL if we encountered an undecipherable augmentation. */
381 static const unsigned char *
382 extract_cie_info (const struct dwarf_cie *cie, struct _Unwind_Context *context,
383 _Unwind_FrameState *fs)
385 const unsigned char *aug = cie->augmentation;
386 const unsigned char *p = aug + strlen ((const char *)aug) + 1;
387 const unsigned char *ret = NULL;
391 /* g++ v2 "eh" has pointer immediately following augmentation string,
392 so it must be handled first. */
393 if (aug[0] == 'e' && aug[1] == 'h')
395 fs->eh_ptr = read_pointer (p);
396 p += sizeof (void *);
400 /* After the augmentation resp. pointer for "eh" augmentation
401 follows for CIE version >= 4 address size byte and
402 segment size byte. */
403 if (__builtin_expect (cie->version >= 4, 0))
405 if (p[0] != sizeof (void *) || p[1] != 0)
409 /* Immediately following this are the code and
410 data alignment and return address column. */
411 p = read_uleb128 (p, &utmp);
412 fs->code_align = (_Unwind_Word)utmp;
413 p = read_sleb128 (p, &stmp);
414 fs->data_align = (_Unwind_Sword)stmp;
415 if (cie->version == 1)
416 fs->retaddr_column = *p++;
419 p = read_uleb128 (p, &utmp);
420 fs->retaddr_column = (_Unwind_Word)utmp;
422 fs->lsda_encoding = DW_EH_PE_omit;
424 /* If the augmentation starts with 'z', then a uleb128 immediately
425 follows containing the length of the augmentation field following
429 p = read_uleb128 (p, &utmp);
436 /* Iterate over recognized augmentation subsequences. */
439 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
442 fs->lsda_encoding = *p++;
446 /* "R" indicates a byte indicating how FDE addresses are encoded. */
447 else if (aug[0] == 'R')
449 fs->fde_encoding = *p++;
453 /* "P" indicates a personality routine in the CIE augmentation. */
454 else if (aug[0] == 'P')
456 _Unwind_Ptr personality;
458 p = read_encoded_value (context, *p, p + 1, &personality);
459 fs->personality = (_Unwind_Personality_Fn) personality;
463 /* "S" indicates a signal frame. */
464 else if (aug[0] == 'S')
466 fs->signal_frame = 1;
470 /* Otherwise we have an unknown augmentation string.
471 Bail unless we saw a 'z' prefix. */
476 return ret ? ret : p;
480 /* Decode a DW_OP stack program. Return the top of stack. Push INITIAL
481 onto the stack to start. */
484 execute_stack_op (const unsigned char *op_ptr, const unsigned char *op_end,
485 struct _Unwind_Context *context, _Unwind_Word initial)
487 _Unwind_Word stack[64]; /* ??? Assume this is enough. */
493 while (op_ptr < op_end)
495 enum dwarf_location_atom op = *op_ptr++;
497 _uleb128_t reg, utmp;
498 _sleb128_t offset, stmp;
534 result = op - DW_OP_lit0;
538 result = (_Unwind_Word) (_Unwind_Ptr) read_pointer (op_ptr);
539 op_ptr += sizeof (void *);
542 case DW_OP_GNU_encoded_addr:
545 op_ptr = read_encoded_value (context, *op_ptr, op_ptr+1, &presult);
551 result = read_1u (op_ptr);
555 result = read_1s (op_ptr);
559 result = read_2u (op_ptr);
563 result = read_2s (op_ptr);
567 result = read_4u (op_ptr);
571 result = read_4s (op_ptr);
575 result = read_8u (op_ptr);
579 result = read_8s (op_ptr);
583 op_ptr = read_uleb128 (op_ptr, &utmp);
584 result = (_Unwind_Word)utmp;
587 op_ptr = read_sleb128 (op_ptr, &stmp);
588 result = (_Unwind_Sword)stmp;
623 result = _Unwind_GetGR (context, op - DW_OP_reg0);
626 op_ptr = read_uleb128 (op_ptr, ®);
627 result = _Unwind_GetGR (context, reg);
662 op_ptr = read_sleb128 (op_ptr, &offset);
663 result = _Unwind_GetGR (context, op - DW_OP_breg0) + offset;
666 op_ptr = read_uleb128 (op_ptr, ®);
667 op_ptr = read_sleb128 (op_ptr, &offset);
668 result = _Unwind_GetGR (context, reg) + (_Unwind_Word)offset;
672 gcc_assert (stack_elt);
673 result = stack[stack_elt - 1];
677 gcc_assert (stack_elt);
683 gcc_assert (offset < stack_elt - 1);
684 result = stack[stack_elt - 1 - offset];
688 gcc_assert (stack_elt >= 2);
689 result = stack[stack_elt - 2];
695 gcc_assert (stack_elt >= 2);
696 t = stack[stack_elt - 1];
697 stack[stack_elt - 1] = stack[stack_elt - 2];
698 stack[stack_elt - 2] = t;
704 _Unwind_Word t1, t2, t3;
706 gcc_assert (stack_elt >= 3);
707 t1 = stack[stack_elt - 1];
708 t2 = stack[stack_elt - 2];
709 t3 = stack[stack_elt - 3];
710 stack[stack_elt - 1] = t2;
711 stack[stack_elt - 2] = t3;
712 stack[stack_elt - 3] = t1;
717 case DW_OP_deref_size:
721 case DW_OP_plus_uconst:
722 /* Unary operations. */
723 gcc_assert (stack_elt);
726 result = stack[stack_elt];
732 void *ptr = (void *) (_Unwind_Ptr) result;
733 result = (_Unwind_Ptr) read_pointer (ptr);
737 case DW_OP_deref_size:
739 void *ptr = (void *) (_Unwind_Ptr) result;
743 result = read_1u (ptr);
746 result = read_2u (ptr);
749 result = read_4u (ptr);
752 result = read_8u (ptr);
761 if ((_Unwind_Sword) result < 0)
770 case DW_OP_plus_uconst:
771 op_ptr = read_uleb128 (op_ptr, &utmp);
772 result += (_Unwind_Word)utmp;
798 /* Binary operations. */
799 _Unwind_Word first, second;
800 gcc_assert (stack_elt >= 2);
803 second = stack[stack_elt];
804 first = stack[stack_elt + 1];
809 result = second & first;
812 result = (_Unwind_Sword) second / (_Unwind_Sword) first;
815 result = second - first;
818 result = second % first;
821 result = second * first;
824 result = second | first;
827 result = second + first;
830 result = second << first;
833 result = second >> first;
836 result = (_Unwind_Sword) second >> first;
839 result = second ^ first;
842 result = (_Unwind_Sword) second <= (_Unwind_Sword) first;
845 result = (_Unwind_Sword) second >= (_Unwind_Sword) first;
848 result = (_Unwind_Sword) second == (_Unwind_Sword) first;
851 result = (_Unwind_Sword) second < (_Unwind_Sword) first;
854 result = (_Unwind_Sword) second > (_Unwind_Sword) first;
857 result = (_Unwind_Sword) second != (_Unwind_Sword) first;
867 offset = read_2s (op_ptr);
873 gcc_assert (stack_elt);
876 offset = read_2s (op_ptr);
878 if (stack[stack_elt] != 0)
889 /* Most things push a result value. */
890 gcc_assert ((size_t) stack_elt < sizeof(stack)/sizeof(*stack));
891 stack[stack_elt++] = result;
895 /* We were executing this program to get a value. It should be
897 gcc_assert (stack_elt);
899 return stack[stack_elt];
903 /* Decode DWARF 2 call frame information. Takes pointers the
904 instruction sequence to decode, current register information and
905 CIE info, and the PC range to evaluate. */
908 execute_cfa_program (const unsigned char *insn_ptr,
909 const unsigned char *insn_end,
910 struct _Unwind_Context *context,
911 _Unwind_FrameState *fs)
913 struct frame_state_reg_info *unused_rs = NULL;
915 /* Don't allow remember/restore between CIE and FDE programs. */
916 fs->regs.prev = NULL;
918 /* The comparison with the return address uses < rather than <= because
919 we are only interested in the effects of code before the call; for a
920 noreturn function, the return address may point to unrelated code with
921 a different stack configuration that we are not interested in. We
922 assume that the call itself is unwind info-neutral; if not, or if
923 there are delay instructions that adjust the stack, these must be
924 reflected at the point immediately before the call insn.
925 In signal frames, return address is after last completed instruction,
926 so we add 1 to return address to make the comparison <=. */
927 while (insn_ptr < insn_end
928 && fs->pc < context->ra + _Unwind_IsSignalFrame (context))
930 unsigned char insn = *insn_ptr++;
931 _uleb128_t reg, utmp;
932 _sleb128_t offset, stmp;
934 if ((insn & 0xc0) == DW_CFA_advance_loc)
935 fs->pc += (insn & 0x3f) * fs->code_align;
936 else if ((insn & 0xc0) == DW_CFA_offset)
939 insn_ptr = read_uleb128 (insn_ptr, &utmp);
940 offset = (_Unwind_Sword) utmp * fs->data_align;
941 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].how
943 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].loc.offset = offset;
945 else if ((insn & 0xc0) == DW_CFA_restore)
948 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].how = REG_UNSAVED;
956 insn_ptr = read_encoded_value (context, fs->fde_encoding,
958 fs->pc = (void *) pc;
962 case DW_CFA_advance_loc1:
963 fs->pc += read_1u (insn_ptr) * fs->code_align;
966 case DW_CFA_advance_loc2:
967 fs->pc += read_2u (insn_ptr) * fs->code_align;
970 case DW_CFA_advance_loc4:
971 fs->pc += read_4u (insn_ptr) * fs->code_align;
975 case DW_CFA_offset_extended:
976 insn_ptr = read_uleb128 (insn_ptr, ®);
977 insn_ptr = read_uleb128 (insn_ptr, &utmp);
978 offset = (_Unwind_Sword) utmp * fs->data_align;
979 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].how
981 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].loc.offset = offset;
984 case DW_CFA_restore_extended:
985 insn_ptr = read_uleb128 (insn_ptr, ®);
986 /* FIXME, this is wrong; the CIE might have said that the
987 register was saved somewhere. */
988 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN(reg)].how = REG_UNSAVED;
991 case DW_CFA_same_value:
992 insn_ptr = read_uleb128 (insn_ptr, ®);
993 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN(reg)].how = REG_UNSAVED;
996 case DW_CFA_undefined:
997 insn_ptr = read_uleb128 (insn_ptr, ®);
998 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN(reg)].how = REG_UNDEFINED;
1004 case DW_CFA_register:
1007 insn_ptr = read_uleb128 (insn_ptr, ®);
1008 insn_ptr = read_uleb128 (insn_ptr, ®2);
1009 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].how = REG_SAVED_REG;
1010 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].loc.reg =
1015 case DW_CFA_remember_state:
1017 struct frame_state_reg_info *new_rs;
1021 unused_rs = unused_rs->prev;
1024 new_rs = alloca (sizeof (struct frame_state_reg_info));
1027 fs->regs.prev = new_rs;
1031 case DW_CFA_restore_state:
1033 struct frame_state_reg_info *old_rs = fs->regs.prev;
1035 old_rs->prev = unused_rs;
1040 case DW_CFA_def_cfa:
1041 insn_ptr = read_uleb128 (insn_ptr, &utmp);
1042 fs->regs.cfa_reg = (_Unwind_Word)utmp;
1043 insn_ptr = read_uleb128 (insn_ptr, &utmp);
1044 fs->regs.cfa_offset = (_Unwind_Word)utmp;
1045 fs->regs.cfa_how = CFA_REG_OFFSET;
1048 case DW_CFA_def_cfa_register:
1049 insn_ptr = read_uleb128 (insn_ptr, &utmp);
1050 fs->regs.cfa_reg = (_Unwind_Word)utmp;
1051 fs->regs.cfa_how = CFA_REG_OFFSET;
1054 case DW_CFA_def_cfa_offset:
1055 insn_ptr = read_uleb128 (insn_ptr, &utmp);
1056 fs->regs.cfa_offset = utmp;
1057 /* cfa_how deliberately not set. */
1060 case DW_CFA_def_cfa_expression:
1061 fs->regs.cfa_exp = insn_ptr;
1062 fs->regs.cfa_how = CFA_EXP;
1063 insn_ptr = read_uleb128 (insn_ptr, &utmp);
1067 case DW_CFA_expression:
1068 insn_ptr = read_uleb128 (insn_ptr, ®);
1069 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].how = REG_SAVED_EXP;
1070 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].loc.exp = insn_ptr;
1071 insn_ptr = read_uleb128 (insn_ptr, &utmp);
1076 case DW_CFA_offset_extended_sf:
1077 insn_ptr = read_uleb128 (insn_ptr, ®);
1078 insn_ptr = read_sleb128 (insn_ptr, &stmp);
1079 offset = stmp * fs->data_align;
1080 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].how
1082 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].loc.offset = offset;
1085 case DW_CFA_def_cfa_sf:
1086 insn_ptr = read_uleb128 (insn_ptr, &utmp);
1087 fs->regs.cfa_reg = (_Unwind_Word)utmp;
1088 insn_ptr = read_sleb128 (insn_ptr, &stmp);
1089 fs->regs.cfa_offset = (_Unwind_Sword)stmp;
1090 fs->regs.cfa_how = CFA_REG_OFFSET;
1091 fs->regs.cfa_offset *= fs->data_align;
1094 case DW_CFA_def_cfa_offset_sf:
1095 insn_ptr = read_sleb128 (insn_ptr, &stmp);
1096 fs->regs.cfa_offset = (_Unwind_Sword)stmp;
1097 fs->regs.cfa_offset *= fs->data_align;
1098 /* cfa_how deliberately not set. */
1101 case DW_CFA_val_offset:
1102 insn_ptr = read_uleb128 (insn_ptr, ®);
1103 insn_ptr = read_uleb128 (insn_ptr, &utmp);
1104 offset = (_Unwind_Sword) utmp * fs->data_align;
1105 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].how
1106 = REG_SAVED_VAL_OFFSET;
1107 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].loc.offset = offset;
1110 case DW_CFA_val_offset_sf:
1111 insn_ptr = read_uleb128 (insn_ptr, ®);
1112 insn_ptr = read_sleb128 (insn_ptr, &stmp);
1113 offset = stmp * fs->data_align;
1114 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].how
1115 = REG_SAVED_VAL_OFFSET;
1116 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].loc.offset = offset;
1119 case DW_CFA_val_expression:
1120 insn_ptr = read_uleb128 (insn_ptr, ®);
1121 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].how
1122 = REG_SAVED_VAL_EXP;
1123 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].loc.exp = insn_ptr;
1124 insn_ptr = read_uleb128 (insn_ptr, &utmp);
1128 case DW_CFA_GNU_window_save:
1129 /* ??? Hardcoded for SPARC register window configuration. */
1130 for (reg = 16; reg < 32; ++reg)
1132 fs->regs.reg[reg].how = REG_SAVED_OFFSET;
1133 fs->regs.reg[reg].loc.offset = (reg - 16) * sizeof (void *);
1137 case DW_CFA_GNU_args_size:
1138 insn_ptr = read_uleb128 (insn_ptr, &utmp);
1139 context->args_size = (_Unwind_Word)utmp;
1142 case DW_CFA_GNU_negative_offset_extended:
1143 /* Obsoleted by DW_CFA_offset_extended_sf, but used by
1144 older PowerPC code. */
1145 insn_ptr = read_uleb128 (insn_ptr, ®);
1146 insn_ptr = read_uleb128 (insn_ptr, &utmp);
1147 offset = (_Unwind_Word) utmp * fs->data_align;
1148 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].how
1150 fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (reg)].loc.offset = -offset;
1159 /* Given the _Unwind_Context CONTEXT for a stack frame, look up the FDE for
1160 its caller and decode it into FS. This function also sets the
1161 args_size and lsda members of CONTEXT, as they are really information
1162 about the caller's frame. */
1164 static _Unwind_Reason_Code
1165 uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs)
1167 const struct dwarf_fde *fde;
1168 const struct dwarf_cie *cie;
1169 const unsigned char *aug, *insn, *end;
1171 memset (fs, 0, sizeof (*fs));
1172 context->args_size = 0;
1175 if (context->ra == 0)
1176 return _URC_END_OF_STACK;
1178 fde = _Unwind_Find_FDE (context->ra + _Unwind_IsSignalFrame (context) - 1,
1182 #ifdef MD_FALLBACK_FRAME_STATE_FOR
1183 /* Couldn't find frame unwind info for this function. Try a
1184 target-specific fallback mechanism. This will necessarily
1185 not provide a personality routine or LSDA. */
1186 return MD_FALLBACK_FRAME_STATE_FOR (context, fs);
1188 return _URC_END_OF_STACK;
1192 fs->pc = context->bases.func;
1194 cie = get_cie (fde);
1195 insn = extract_cie_info (cie, context, fs);
1197 /* CIE contained unknown augmentation. */
1198 return _URC_FATAL_PHASE1_ERROR;
1200 /* First decode all the insns in the CIE. */
1201 end = (const unsigned char *) next_fde ((const struct dwarf_fde *) cie);
1202 execute_cfa_program (insn, end, context, fs);
1204 /* Locate augmentation for the fde. */
1205 aug = (const unsigned char *) fde + sizeof (*fde);
1206 aug += 2 * size_of_encoded_value (fs->fde_encoding);
1211 aug = read_uleb128 (aug, &i);
1214 if (fs->lsda_encoding != DW_EH_PE_omit)
1218 aug = read_encoded_value (context, fs->lsda_encoding, aug, &lsda);
1219 context->lsda = (void *) lsda;
1222 /* Then the insns in the FDE up to our target PC. */
1225 end = (const unsigned char *) next_fde (fde);
1226 execute_cfa_program (insn, end, context, fs);
1228 return _URC_NO_REASON;
1231 typedef struct frame_state
1237 long reg_or_offset[PRE_GCC3_DWARF_FRAME_REGISTERS+1];
1238 unsigned short cfa_reg;
1239 unsigned short retaddr_column;
1240 char saved[PRE_GCC3_DWARF_FRAME_REGISTERS+1];
1243 struct frame_state * __frame_state_for (void *, struct frame_state *);
1245 /* Called from pre-G++ 3.0 __throw to find the registers to restore for
1246 a given PC_TARGET. The caller should allocate a local variable of
1247 `struct frame_state' and pass its address to STATE_IN. */
1249 struct frame_state *
1250 __frame_state_for (void *pc_target, struct frame_state *state_in)
1252 struct _Unwind_Context context;
1253 _Unwind_FrameState fs;
1256 memset (&context, 0, sizeof (struct _Unwind_Context));
1257 if (!ASSUME_EXTENDED_UNWIND_CONTEXT)
1258 context.flags = EXTENDED_CONTEXT_BIT;
1259 context.ra = pc_target + 1;
1261 if (uw_frame_state_for (&context, &fs) != _URC_NO_REASON)
1264 /* We have no way to pass a location expression for the CFA to our
1265 caller. It wouldn't understand it anyway. */
1266 if (fs.regs.cfa_how == CFA_EXP)
1269 for (reg = 0; reg < PRE_GCC3_DWARF_FRAME_REGISTERS + 1; reg++)
1271 state_in->saved[reg] = fs.regs.reg[reg].how;
1272 switch (state_in->saved[reg])
1275 state_in->reg_or_offset[reg] = fs.regs.reg[reg].loc.reg;
1277 case REG_SAVED_OFFSET:
1278 state_in->reg_or_offset[reg] = fs.regs.reg[reg].loc.offset;
1281 state_in->reg_or_offset[reg] = 0;
1286 state_in->cfa_offset = fs.regs.cfa_offset;
1287 state_in->cfa_reg = fs.regs.cfa_reg;
1288 state_in->retaddr_column = fs.retaddr_column;
1289 state_in->args_size = context.args_size;
1290 state_in->eh_ptr = fs.eh_ptr;
1295 typedef union { _Unwind_Ptr ptr; _Unwind_Word word; } _Unwind_SpTmp;
1298 _Unwind_SetSpColumn (struct _Unwind_Context *context, void *cfa,
1299 _Unwind_SpTmp *tmp_sp)
1301 int size = dwarf_reg_size_table[__builtin_dwarf_sp_column ()];
1303 if (size == sizeof(_Unwind_Ptr))
1304 tmp_sp->ptr = (_Unwind_Ptr) cfa;
1307 gcc_assert (size == sizeof(_Unwind_Word));
1308 tmp_sp->word = (_Unwind_Ptr) cfa;
1310 _Unwind_SetGRPtr (context, __builtin_dwarf_sp_column (), tmp_sp);
1314 uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
1316 struct _Unwind_Context orig_context = *context;
1320 #ifdef EH_RETURN_STACKADJ_RTX
1321 /* Special handling here: Many machines do not use a frame pointer,
1322 and track the CFA only through offsets from the stack pointer from
1323 one frame to the next. In this case, the stack pointer is never
1324 stored, so it has no saved address in the context. What we do
1325 have is the CFA from the previous stack frame.
1327 In very special situations (such as unwind info for signal return),
1328 there may be location expressions that use the stack pointer as well.
1330 Do this conditionally for one frame. This allows the unwind info
1331 for one frame to save a copy of the stack pointer from the previous
1332 frame, and be able to use much easier CFA mechanisms to do it.
1333 Always zap the saved stack pointer value for the next frame; carrying
1334 the value over from one frame to another doesn't make sense. */
1336 _Unwind_SpTmp tmp_sp;
1338 if (!_Unwind_GetGRPtr (&orig_context, __builtin_dwarf_sp_column ()))
1339 _Unwind_SetSpColumn (&orig_context, context->cfa, &tmp_sp);
1340 _Unwind_SetGRPtr (context, __builtin_dwarf_sp_column (), NULL);
1343 /* Compute this frame's CFA. */
1344 switch (fs->regs.cfa_how)
1346 case CFA_REG_OFFSET:
1347 cfa = _Unwind_GetPtr (&orig_context, fs->regs.cfa_reg);
1348 cfa += fs->regs.cfa_offset;
1353 const unsigned char *exp = fs->regs.cfa_exp;
1356 exp = read_uleb128 (exp, &len);
1357 cfa = (void *) (_Unwind_Ptr)
1358 execute_stack_op (exp, exp + len, &orig_context, 0);
1367 /* Compute the addresses of all registers saved in this frame. */
1368 for (i = 0; i < DWARF_FRAME_REGISTERS + 1; ++i)
1369 switch (fs->regs.reg[i].how)
1375 case REG_SAVED_OFFSET:
1376 _Unwind_SetGRPtr (context, i,
1377 (void *) (cfa + fs->regs.reg[i].loc.offset));
1381 if (_Unwind_GRByValue (&orig_context, fs->regs.reg[i].loc.reg))
1382 _Unwind_SetGRValue (context, i,
1383 _Unwind_GetGR (&orig_context,
1384 fs->regs.reg[i].loc.reg));
1386 _Unwind_SetGRPtr (context, i,
1387 _Unwind_GetGRPtr (&orig_context,
1388 fs->regs.reg[i].loc.reg));
1393 const unsigned char *exp = fs->regs.reg[i].loc.exp;
1397 exp = read_uleb128 (exp, &len);
1398 val = execute_stack_op (exp, exp + len, &orig_context,
1400 _Unwind_SetGRPtr (context, i, (void *) val);
1404 case REG_SAVED_VAL_OFFSET:
1405 _Unwind_SetGRValue (context, i,
1406 (_Unwind_Internal_Ptr)
1407 (cfa + fs->regs.reg[i].loc.offset));
1410 case REG_SAVED_VAL_EXP:
1412 const unsigned char *exp = fs->regs.reg[i].loc.exp;
1416 exp = read_uleb128 (exp, &len);
1417 val = execute_stack_op (exp, exp + len, &orig_context,
1419 _Unwind_SetGRValue (context, i, val);
1424 _Unwind_SetSignalFrame (context, fs->signal_frame);
1426 #ifdef MD_FROB_UPDATE_CONTEXT
1427 MD_FROB_UPDATE_CONTEXT (context, fs);
1431 /* CONTEXT describes the unwind state for a frame, and FS describes the FDE
1432 of its caller. Update CONTEXT to refer to the caller as well. Note
1433 that the args_size and lsda members are not updated here, but later in
1434 uw_frame_state_for. */
1437 uw_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
1439 uw_update_context_1 (context, fs);
1441 /* In general this unwinder doesn't make any distinction between
1442 undefined and same_value rule. Call-saved registers are assumed
1443 to have same_value rule by default and explicit undefined
1444 rule is handled like same_value. The only exception is
1445 DW_CFA_undefined on retaddr_column which is supposed to
1446 mark outermost frame in DWARF 3. */
1447 if (fs->regs.reg[DWARF_REG_TO_UNWIND_COLUMN (fs->retaddr_column)].how
1449 /* uw_frame_state_for uses context->ra == 0 check to find outermost
1453 /* Compute the return address now, since the return address column
1454 can change from frame to frame. */
1455 context->ra = __builtin_extract_return_addr
1456 (_Unwind_GetPtr (context, fs->retaddr_column));
1460 uw_advance_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
1462 uw_update_context (context, fs);
1465 /* Fill in CONTEXT for top-of-stack. The only valid registers at this
1466 level will be the return address and the CFA. */
1468 #define uw_init_context(CONTEXT) \
1471 /* Do any necessary initialization to access arbitrary stack frames. \
1472 On the SPARC, this means flushing the register windows. */ \
1473 __builtin_unwind_init (); \
1474 uw_init_context_1 (CONTEXT, __builtin_dwarf_cfa (), \
1475 __builtin_return_address (0)); \
1480 init_dwarf_reg_size_table (void)
1482 __builtin_init_dwarf_reg_size_table (dwarf_reg_size_table);
1485 static void __attribute__((noinline))
1486 uw_init_context_1 (struct _Unwind_Context *context,
1487 void *outer_cfa, void *outer_ra)
1489 void *ra = __builtin_extract_return_addr (__builtin_return_address (0));
1490 _Unwind_FrameState fs;
1491 _Unwind_SpTmp sp_slot;
1492 _Unwind_Reason_Code code;
1494 memset (context, 0, sizeof (struct _Unwind_Context));
1496 if (!ASSUME_EXTENDED_UNWIND_CONTEXT)
1497 context->flags = EXTENDED_CONTEXT_BIT;
1499 code = uw_frame_state_for (context, &fs);
1500 gcc_assert (code == _URC_NO_REASON);
1504 static __gthread_once_t once_regsizes = __GTHREAD_ONCE_INIT;
1505 if (__gthread_once (&once_regsizes, init_dwarf_reg_size_table) != 0
1506 && dwarf_reg_size_table[0] == 0)
1507 init_dwarf_reg_size_table ();
1510 if (dwarf_reg_size_table[0] == 0)
1511 init_dwarf_reg_size_table ();
1514 /* Force the frame state to use the known cfa value. */
1515 _Unwind_SetSpColumn (context, outer_cfa, &sp_slot);
1516 fs.regs.cfa_how = CFA_REG_OFFSET;
1517 fs.regs.cfa_reg = __builtin_dwarf_sp_column ();
1518 fs.regs.cfa_offset = 0;
1520 uw_update_context_1 (context, &fs);
1522 /* If the return address column was saved in a register in the
1523 initialization context, then we can't see it in the given
1524 call frame data. So have the initialization context tell us. */
1525 context->ra = __builtin_extract_return_addr (outer_ra);
1528 static void _Unwind_DebugHook (void *, void *)
1529 __attribute__ ((__noinline__, __used__, __noclone__));
1531 /* This function is called during unwinding. It is intended as a hook
1532 for a debugger to intercept exceptions. CFA is the CFA of the
1533 target frame. HANDLER is the PC to which control will be
1536 _Unwind_DebugHook (void *cfa __attribute__ ((__unused__)),
1537 void *handler __attribute__ ((__unused__)))
1539 /* We only want to use stap probes starting with v3. Earlier
1540 versions added too much startup cost. */
1541 #if defined (HAVE_SYS_SDT_H) && defined (STAP_PROBE2) && _SDT_NOTE_TYPE >= 3
1542 STAP_PROBE2 (libgcc, unwind, cfa, handler);
1548 /* Install TARGET into CURRENT so that we can return to it. This is a
1549 macro because __builtin_eh_return must be invoked in the context of
1552 #define uw_install_context(CURRENT, TARGET) \
1555 long offset = uw_install_context_1 ((CURRENT), (TARGET)); \
1556 void *handler = __builtin_frob_return_addr ((TARGET)->ra); \
1557 _Unwind_DebugHook ((TARGET)->cfa, handler); \
1558 __builtin_eh_return (offset, handler); \
1563 uw_install_context_1 (struct _Unwind_Context *current,
1564 struct _Unwind_Context *target)
1567 _Unwind_SpTmp sp_slot;
1569 /* If the target frame does not have a saved stack pointer,
1570 then set up the target's CFA. */
1571 if (!_Unwind_GetGRPtr (target, __builtin_dwarf_sp_column ()))
1572 _Unwind_SetSpColumn (target, target->cfa, &sp_slot);
1574 for (i = 0; i < DWARF_FRAME_REGISTERS; ++i)
1576 void *c = (void *) (_Unwind_Internal_Ptr) current->reg[i];
1577 void *t = (void *) (_Unwind_Internal_Ptr)target->reg[i];
1579 gcc_assert (current->by_value[i] == 0);
1580 if (target->by_value[i] && c)
1584 if (dwarf_reg_size_table[i] == sizeof (_Unwind_Word))
1586 w = (_Unwind_Internal_Ptr) t;
1587 memcpy (c, &w, sizeof (_Unwind_Word));
1591 gcc_assert (dwarf_reg_size_table[i] == sizeof (_Unwind_Ptr));
1592 p = (_Unwind_Internal_Ptr) t;
1593 memcpy (c, &p, sizeof (_Unwind_Ptr));
1596 else if (t && c && t != c)
1597 memcpy (c, t, dwarf_reg_size_table[i]);
1600 /* If the current frame doesn't have a saved stack pointer, then we
1601 need to rely on EH_RETURN_STACKADJ_RTX to get our target stack
1602 pointer value reloaded. */
1603 if (!_Unwind_GetGRPtr (current, __builtin_dwarf_sp_column ()))
1607 target_cfa = _Unwind_GetPtr (target, __builtin_dwarf_sp_column ());
1609 /* We adjust SP by the difference between CURRENT and TARGET's CFA. */
1610 if (STACK_GROWS_DOWNWARD)
1611 return target_cfa - current->cfa + target->args_size;
1613 return current->cfa - target_cfa - target->args_size;
1618 static inline _Unwind_Ptr
1619 uw_identify_context (struct _Unwind_Context *context)
1621 /* The CFA is not sufficient to disambiguate the context of a function
1622 interrupted by a signal before establishing its frame and the context
1623 of the signal itself. */
1624 if (STACK_GROWS_DOWNWARD)
1625 return _Unwind_GetCFA (context) - _Unwind_IsSignalFrame (context);
1627 return _Unwind_GetCFA (context) + _Unwind_IsSignalFrame (context);
1631 #include "unwind.inc"
1633 #if defined (USE_GAS_SYMVER) && defined (SHARED) && defined (USE_LIBUNWIND_EXCEPTIONS)
1634 alias (_Unwind_Backtrace);
1635 alias (_Unwind_DeleteException);
1636 alias (_Unwind_FindEnclosingFunction);
1637 alias (_Unwind_ForcedUnwind);
1638 alias (_Unwind_GetDataRelBase);
1639 alias (_Unwind_GetTextRelBase);
1640 alias (_Unwind_GetCFA);
1641 alias (_Unwind_GetGR);
1642 alias (_Unwind_GetIP);
1643 alias (_Unwind_GetLanguageSpecificData);
1644 alias (_Unwind_GetRegionStart);
1645 alias (_Unwind_RaiseException);
1646 alias (_Unwind_Resume);
1647 alias (_Unwind_Resume_or_Rethrow);
1648 alias (_Unwind_SetGR);
1649 alias (_Unwind_SetIP);
1652 #endif /* !USING_SJLJ_EXCEPTIONS */