1 /* DWARF2 exception handling and frame unwind runtime interface routines.
2 Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
25 #include "unwind-pe.h"
26 #include "unwind-dw2-fde.h"
30 #ifndef __USING_SJLJ_EXCEPTIONS__
32 #ifndef STACK_GROWS_DOWNWARD
33 #define STACK_GROWS_DOWNWARD 0
35 #undef STACK_GROWS_DOWNWARD
36 #define STACK_GROWS_DOWNWARD 1
39 /* A target can override (perhaps for backward compatibility) how
40 many dwarf2 columns are unwound. */
41 #ifndef DWARF_FRAME_REGISTERS
42 #define DWARF_FRAME_REGISTERS FIRST_PSEUDO_REGISTER
45 /* Dwarf frame registers used for pre gcc 3.0 compiled glibc. */
46 #ifndef PRE_GCC3_DWARF_FRAME_REGISTERS
47 #define PRE_GCC3_DWARF_FRAME_REGISTERS DWARF_FRAME_REGISTERS
50 /* This is the register and unwind state for a particular frame. */
51 struct _Unwind_Context
53 void *reg[DWARF_FRAME_REGISTERS+1];
57 struct dwarf_eh_bases bases;
58 _Unwind_Word args_size;
61 /* Byte size of every register managed by these routines. */
62 static unsigned char dwarf_reg_size_table[DWARF_FRAME_REGISTERS];
65 /* The result of interpreting the frame unwind info for a frame.
66 This is all symbolic at this point, as none of the values can
67 be resolved until the target pc is located. */
70 /* Each register save state can be described in terms of a CFA slot,
71 another register, or a location expression. */
72 struct frame_state_reg_info
78 const unsigned char *exp;
86 } reg[DWARF_FRAME_REGISTERS+1];
88 /* Used to implement DW_CFA_remember_state. */
89 struct frame_state_reg_info *prev;
92 /* The CFA can be described in terms of a reg+offset or a
93 location expression. */
94 _Unwind_Sword cfa_offset;
96 const unsigned char *cfa_exp;
103 /* The PC described by the current frame state. */
106 /* The information we care about from the CIE/FDE. */
107 _Unwind_Personality_Fn personality;
108 _Unwind_Sword data_align;
109 _Unwind_Word code_align;
110 unsigned char retaddr_column;
111 unsigned char fde_encoding;
112 unsigned char lsda_encoding;
115 } _Unwind_FrameState;
117 /* Read unaligned data from the instruction buffer. */
122 unsigned u2 __attribute__ ((mode (HI)));
123 unsigned u4 __attribute__ ((mode (SI)));
124 unsigned u8 __attribute__ ((mode (DI)));
125 signed s2 __attribute__ ((mode (HI)));
126 signed s4 __attribute__ ((mode (SI)));
127 signed s8 __attribute__ ((mode (DI)));
128 } __attribute__ ((packed));
131 read_pointer (const void *p) { const union unaligned *up = p; return up->p; }
134 read_1u (const void *p) { return *(const unsigned char *)p; }
137 read_1s (const void *p) { return *(const signed char *)p; }
140 read_2u (const void *p) { const union unaligned *up = p; return up->u2; }
143 read_2s (const void *p) { const union unaligned *up = p; return up->s2; }
145 static inline unsigned int
146 read_4u (const void *p) { const union unaligned *up = p; return up->u4; }
149 read_4s (const void *p) { const union unaligned *up = p; return up->s4; }
151 static inline unsigned long
152 read_8u (const void *p) { const union unaligned *up = p; return up->u8; }
154 static inline unsigned long
155 read_8s (const void *p) { const union unaligned *up = p; return up->s8; }
157 /* Get the value of register REG as saved in CONTEXT. */
160 _Unwind_GetGR (struct _Unwind_Context *context, int index)
162 /* This will segfault if the register hasn't been saved. */
163 return * (_Unwind_Word *) context->reg[index];
166 /* Overwrite the saved value for register REG in CONTEXT with VAL. */
169 _Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val)
171 * (_Unwind_Word *) context->reg[index] = val;
174 /* Retrieve the return address for CONTEXT. */
177 _Unwind_GetIP (struct _Unwind_Context *context)
179 return (_Unwind_Ptr) context->ra;
182 /* Overwrite the return address for CONTEXT with VAL. */
185 _Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val)
187 context->ra = (void *) val;
191 _Unwind_GetLanguageSpecificData (struct _Unwind_Context *context)
193 return context->lsda;
197 _Unwind_GetRegionStart (struct _Unwind_Context *context)
199 return (_Unwind_Ptr) context->bases.func;
204 _Unwind_GetDataRelBase (struct _Unwind_Context *context)
206 return (_Unwind_Ptr) context->bases.dbase;
210 _Unwind_GetTextRelBase (struct _Unwind_Context *context)
212 return (_Unwind_Ptr) context->bases.tbase;
216 /* Extract any interesting information from the CIE for the translation
217 unit F belongs to. Return a pointer to the byte after the augmentation,
218 or NULL if we encountered an undecipherable augmentation. */
220 static const unsigned char *
221 extract_cie_info (struct dwarf_cie *cie, struct _Unwind_Context *context,
222 _Unwind_FrameState *fs)
224 const unsigned char *aug = cie->augmentation;
225 const unsigned char *p = aug + strlen (aug) + 1;
226 const unsigned char *ret = NULL;
229 /* g++ v2 "eh" has pointer immediately following augmentation string,
230 so it must be handled first. */
231 if (aug[0] == 'e' && aug[1] == 'h')
233 fs->eh_ptr = read_pointer (p);
234 p += sizeof (void *);
238 /* Immediately following the augmentation are the code and
239 data alignment and return address column. */
240 p = read_uleb128 (p, &fs->code_align);
241 p = read_sleb128 (p, &fs->data_align);
242 fs->retaddr_column = *p++;
243 fs->lsda_encoding = DW_EH_PE_omit;
245 /* If the augmentation starts with 'z', then a uleb128 immediately
246 follows containing the length of the augmentation field following
250 p = read_uleb128 (p, &utmp);
257 /* Iterate over recognized augmentation subsequences. */
260 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
263 fs->lsda_encoding = *p++;
267 /* "R" indicates a byte indicating how FDE addresses are encoded. */
268 else if (aug[0] == 'R')
270 fs->fde_encoding = *p++;
274 /* "P" indicates a personality routine in the CIE augmentation. */
275 else if (aug[0] == 'P')
277 p = read_encoded_value (context, *p, p + 1,
278 (_Unwind_Ptr *) &fs->personality);
282 /* Otherwise we have an unknown augmentation string.
283 Bail unless we saw a 'z' prefix. */
288 return ret ? ret : p;
292 /* Decode a DW_OP stack program. Return the top of stack. Push INITIAL
293 onto the stack to start. */
296 execute_stack_op (const unsigned char *op_ptr, const unsigned char *op_end,
297 struct _Unwind_Context *context, _Unwind_Word initial)
299 _Unwind_Word stack[64]; /* ??? Assume this is enough. */
305 while (op_ptr < op_end)
307 enum dwarf_location_atom op = *op_ptr++;
308 _Unwind_Word result, reg, utmp;
309 _Unwind_Sword offset, stmp;
345 result = op - DW_OP_lit0;
349 result = (_Unwind_Word) (_Unwind_Ptr) read_pointer (op_ptr);
350 op_ptr += sizeof (void *);
354 result = read_1u (op_ptr);
358 result = read_1s (op_ptr);
362 result = read_2u (op_ptr);
366 result = read_2s (op_ptr);
370 result = read_4u (op_ptr);
374 result = read_4s (op_ptr);
378 result = read_8u (op_ptr);
382 result = read_8s (op_ptr);
386 op_ptr = read_uleb128 (op_ptr, &result);
389 op_ptr = read_sleb128 (op_ptr, &stmp);
425 result = _Unwind_GetGR (context, op - DW_OP_reg0);
428 op_ptr = read_uleb128 (op_ptr, ®);
429 result = _Unwind_GetGR (context, reg);
464 op_ptr = read_sleb128 (op_ptr, &offset);
465 result = _Unwind_GetGR (context, op - DW_OP_breg0) + offset;
468 op_ptr = read_uleb128 (op_ptr, ®);
469 op_ptr = read_sleb128 (op_ptr, &offset);
470 result = _Unwind_GetGR (context, reg) + offset;
476 result = stack[stack_elt - 1];
486 if (offset >= stack_elt - 1)
488 result = stack[stack_elt - 1 - offset];
494 result = stack[stack_elt - 2];
499 _Unwind_Word t1, t2, t3;
503 t1 = stack[stack_elt - 1];
504 t2 = stack[stack_elt - 2];
505 t3 = stack[stack_elt - 3];
506 stack[stack_elt - 1] = t2;
507 stack[stack_elt - 2] = t3;
508 stack[stack_elt - 3] = t1;
513 case DW_OP_deref_size:
517 case DW_OP_plus_uconst:
518 /* Unary operations. */
521 result = stack[stack_elt];
527 void *ptr = (void *)(_Unwind_Ptr) result;
528 result = (_Unwind_Ptr) read_pointer (ptr);
532 case DW_OP_deref_size:
534 void *ptr = (void *)(_Unwind_Ptr) result;
538 result = read_1u (ptr);
541 result = read_2u (ptr);
544 result = read_4u (ptr);
547 result = read_8u (ptr);
556 if ((_Unwind_Sword) result < 0)
565 case DW_OP_plus_uconst:
566 op_ptr = read_uleb128 (op_ptr, &utmp);
589 /* Binary operations. */
590 _Unwind_Word first, second;
591 if ((stack_elt -= 2) < 0)
593 second = stack[stack_elt];
594 first = stack[stack_elt + 1];
599 result = second & first;
602 result = (_Unwind_Sword)second / (_Unwind_Sword)first;
605 result = second - first;
608 result = (_Unwind_Sword)second % (_Unwind_Sword)first;
611 result = second * first;
614 result = second | first;
617 result = second + first;
620 result = second << first;
623 result = second >> first;
626 result = (_Unwind_Sword)second >> first;
629 result = second ^ first;
632 result = (_Unwind_Sword)first <= (_Unwind_Sword)second;
635 result = (_Unwind_Sword)first >= (_Unwind_Sword)second;
638 result = (_Unwind_Sword)first == (_Unwind_Sword)second;
641 result = (_Unwind_Sword)first < (_Unwind_Sword)second;
644 result = (_Unwind_Sword)first > (_Unwind_Sword)second;
647 result = (_Unwind_Sword)first != (_Unwind_Sword)second;
657 offset = read_2s (op_ptr);
665 offset = read_2s (op_ptr);
667 if (stack[stack_elt] != 0)
678 /* Most things push a result value. */
679 if ((size_t) stack_elt >= sizeof(stack)/sizeof(*stack))
681 stack[++stack_elt] = result;
685 /* We were executing this program to get a value. It should be
689 return stack[stack_elt];
693 /* Decode DWARF 2 call frame information. Takes pointers the
694 instruction sequence to decode, current register information and
695 CIE info, and the PC range to evaluate. */
698 execute_cfa_program (const unsigned char *insn_ptr,
699 const unsigned char *insn_end,
700 struct _Unwind_Context *context,
701 _Unwind_FrameState *fs)
703 struct frame_state_reg_info *unused_rs = NULL;
705 /* Don't allow remember/restore between CIE and FDE programs. */
706 fs->regs.prev = NULL;
708 /* The comparison with the return address uses < rather than <= because
709 we are only interested in the effects of code before the call; for a
710 noreturn function, the return address may point to unrelated code with
711 a different stack configuration that we are not interested in. We
712 assume that the call itself is unwind info-neutral; if not, or if
713 there are delay instructions that adjust the stack, these must be
714 reflected at the point immediately before the call insn. */
715 while (insn_ptr < insn_end && fs->pc < context->ra)
717 unsigned char insn = *insn_ptr++;
718 _Unwind_Word reg, utmp;
719 _Unwind_Sword offset, stmp;
721 if ((insn & 0xc0) == DW_CFA_advance_loc)
722 fs->pc += (insn & 0x3f) * fs->code_align;
723 else if ((insn & 0xc0) == DW_CFA_offset)
726 insn_ptr = read_uleb128 (insn_ptr, &utmp);
727 offset = (_Unwind_Sword)utmp * fs->data_align;
728 fs->regs.reg[reg].how = REG_SAVED_OFFSET;
729 fs->regs.reg[reg].loc.offset = offset;
731 else if ((insn & 0xc0) == DW_CFA_restore)
734 fs->regs.reg[reg].how = REG_UNSAVED;
739 insn_ptr = read_encoded_value (context, fs->fde_encoding,
740 insn_ptr, (_Unwind_Ptr *) &fs->pc);
743 case DW_CFA_advance_loc1:
744 fs->pc += read_1u (insn_ptr) * fs->code_align;
747 case DW_CFA_advance_loc2:
748 fs->pc += read_2u (insn_ptr) * fs->code_align;
751 case DW_CFA_advance_loc4:
752 fs->pc += read_4u (insn_ptr) * fs->code_align;
756 case DW_CFA_offset_extended:
757 insn_ptr = read_uleb128 (insn_ptr, ®);
758 insn_ptr = read_uleb128 (insn_ptr, &utmp);
759 offset = (_Unwind_Sword)utmp * fs->data_align;
760 fs->regs.reg[reg].how = REG_SAVED_OFFSET;
761 fs->regs.reg[reg].loc.offset = offset;
764 case DW_CFA_restore_extended:
765 insn_ptr = read_uleb128 (insn_ptr, ®);
766 fs->regs.reg[reg].how = REG_UNSAVED;
769 case DW_CFA_undefined:
770 case DW_CFA_same_value:
774 case DW_CFA_register:
777 insn_ptr = read_uleb128 (insn_ptr, ®);
778 insn_ptr = read_uleb128 (insn_ptr, ®2);
779 fs->regs.reg[reg].how = REG_SAVED_REG;
780 fs->regs.reg[reg].loc.reg = reg2;
784 case DW_CFA_remember_state:
786 struct frame_state_reg_info *new_rs;
790 unused_rs = unused_rs->prev;
793 new_rs = __builtin_alloca (sizeof (struct frame_state_reg_info));
796 fs->regs.prev = new_rs;
800 case DW_CFA_restore_state:
802 struct frame_state_reg_info *old_rs = fs->regs.prev;
804 old_rs->prev = unused_rs;
810 insn_ptr = read_uleb128 (insn_ptr, &fs->cfa_reg);
811 insn_ptr = read_uleb128 (insn_ptr, &utmp);
812 fs->cfa_offset = utmp;
813 fs->cfa_how = CFA_REG_OFFSET;
816 case DW_CFA_def_cfa_register:
817 insn_ptr = read_uleb128 (insn_ptr, &fs->cfa_reg);
818 fs->cfa_how = CFA_REG_OFFSET;
821 case DW_CFA_def_cfa_offset:
822 insn_ptr = read_uleb128 (insn_ptr, &utmp);
823 fs->cfa_offset = utmp;
824 /* cfa_how deliberately not set. */
827 case DW_CFA_def_cfa_expression:
828 insn_ptr = read_uleb128 (insn_ptr, &utmp);
829 fs->cfa_exp = insn_ptr;
830 fs->cfa_how = CFA_EXP;
834 case DW_CFA_expression:
835 insn_ptr = read_uleb128 (insn_ptr, ®);
836 insn_ptr = read_uleb128 (insn_ptr, &utmp);
837 fs->regs.reg[reg].how = REG_SAVED_EXP;
838 fs->regs.reg[reg].loc.exp = insn_ptr;
842 /* From the 2.1 draft. */
843 case DW_CFA_offset_extended_sf:
844 insn_ptr = read_uleb128 (insn_ptr, ®);
845 insn_ptr = read_sleb128 (insn_ptr, &stmp);
846 offset = stmp * fs->data_align;
847 fs->regs.reg[reg].how = REG_SAVED_OFFSET;
848 fs->regs.reg[reg].loc.offset = offset;
851 case DW_CFA_def_cfa_sf:
852 insn_ptr = read_uleb128 (insn_ptr, &fs->cfa_reg);
853 insn_ptr = read_sleb128 (insn_ptr, &fs->cfa_offset);
854 fs->cfa_how = CFA_REG_OFFSET;
857 case DW_CFA_def_cfa_offset_sf:
858 insn_ptr = read_sleb128 (insn_ptr, &fs->cfa_offset);
859 /* cfa_how deliberately not set. */
862 case DW_CFA_GNU_window_save:
863 /* ??? Hardcoded for SPARC register window configuration. */
864 for (reg = 16; reg < 32; ++reg)
866 fs->regs.reg[reg].how = REG_SAVED_OFFSET;
867 fs->regs.reg[reg].loc.offset = (reg - 16) * sizeof (void *);
871 case DW_CFA_GNU_args_size:
872 insn_ptr = read_uleb128 (insn_ptr, &context->args_size);
875 case DW_CFA_GNU_negative_offset_extended:
876 /* Obsoleted by DW_CFA_offset_extended_sf, but used by
877 older PowerPC code. */
878 insn_ptr = read_uleb128 (insn_ptr, ®);
879 insn_ptr = read_uleb128 (insn_ptr, &utmp);
880 offset = (_Unwind_Word)utmp * fs->data_align;
881 fs->regs.reg[reg].how = REG_SAVED_OFFSET;
882 fs->regs.reg[reg].loc.offset = -offset;
891 static _Unwind_Reason_Code
892 uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs)
894 struct dwarf_fde *fde;
895 struct dwarf_cie *cie;
896 const unsigned char *aug, *insn, *end;
898 memset (fs, 0, sizeof (*fs));
899 context->args_size = 0;
902 fde = _Unwind_Find_FDE (context->ra - 1, &context->bases);
905 /* Couldn't find frame unwind info for this function. Try a
906 target-specific fallback mechanism. This will necessarily
907 not provide a personality routine or LSDA. */
908 #ifdef MD_FALLBACK_FRAME_STATE_FOR
909 MD_FALLBACK_FRAME_STATE_FOR (context, fs, success);
910 return _URC_END_OF_STACK;
912 return _URC_NO_REASON;
914 return _URC_END_OF_STACK;
918 fs->pc = context->bases.func;
921 insn = extract_cie_info (cie, context, fs);
923 /* CIE contained unknown augmentation. */
924 return _URC_FATAL_PHASE1_ERROR;
926 /* First decode all the insns in the CIE. */
927 end = (unsigned char *) next_fde ((struct dwarf_fde *) cie);
928 execute_cfa_program (insn, end, context, fs);
930 /* Locate augmentation for the fde. */
931 aug = (unsigned char *)fde + sizeof (*fde);
932 aug += 2 * size_of_encoded_value (fs->fde_encoding);
937 aug = read_uleb128 (aug, &i);
940 if (fs->lsda_encoding != DW_EH_PE_omit)
941 aug = read_encoded_value (context, fs->lsda_encoding, aug,
942 (_Unwind_Ptr *) &context->lsda);
944 /* Then the insns in the FDE up to our target PC. */
947 end = (unsigned char *) next_fde (fde);
948 execute_cfa_program (insn, end, context, fs);
950 return _URC_NO_REASON;
953 typedef struct frame_state
959 long reg_or_offset[PRE_GCC3_DWARF_FRAME_REGISTERS+1];
960 unsigned short cfa_reg;
961 unsigned short retaddr_column;
962 char saved[PRE_GCC3_DWARF_FRAME_REGISTERS+1];
965 struct frame_state * __frame_state_for (void *, struct frame_state *);
967 /* Called from pre-G++ 3.0 __throw to find the registers to restore for
968 a given PC_TARGET. The caller should allocate a local variable of
969 `struct frame_state' and pass its address to STATE_IN. */
972 __frame_state_for (void *pc_target, struct frame_state *state_in)
974 struct _Unwind_Context context;
975 _Unwind_FrameState fs;
978 memset (&context, 0, sizeof (struct _Unwind_Context));
979 context.ra = pc_target + 1;
981 if (uw_frame_state_for (&context, &fs) != _URC_NO_REASON)
984 /* We have no way to pass a location expression for the CFA to our
985 caller. It wouldn't understand it anyway. */
986 if (fs.cfa_how == CFA_EXP)
989 for (reg = 0; reg < PRE_GCC3_DWARF_FRAME_REGISTERS + 1; reg++)
991 state_in->saved[reg] = fs.regs.reg[reg].how;
992 switch (state_in->saved[reg])
995 state_in->reg_or_offset[reg] = fs.regs.reg[reg].loc.reg;
997 case REG_SAVED_OFFSET:
998 state_in->reg_or_offset[reg] = fs.regs.reg[reg].loc.offset;
1001 state_in->reg_or_offset[reg] = 0;
1006 state_in->cfa_offset = fs.cfa_offset;
1007 state_in->cfa_reg = fs.cfa_reg;
1008 state_in->retaddr_column = fs.retaddr_column;
1009 state_in->args_size = context.args_size;
1010 state_in->eh_ptr = fs.eh_ptr;
1016 uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
1018 struct _Unwind_Context orig_context = *context;
1022 /* Compute this frame's CFA. */
1023 switch (fs->cfa_how)
1025 case CFA_REG_OFFSET:
1026 /* Special handling here: Many machines do not use a frame pointer,
1027 and track the CFA only through offsets from the stack pointer from
1028 one frame to the next. In this case, the stack pointer is never
1029 stored, so it has no saved address in the context. What we do
1030 have is the CFA from the previous stack frame. */
1031 if (context->reg[fs->cfa_reg] == NULL)
1034 cfa = (void *) (_Unwind_Ptr) _Unwind_GetGR (context, fs->cfa_reg);
1035 cfa += fs->cfa_offset;
1039 /* ??? No way of knowing what register number is the stack pointer
1040 to do the same sort of handling as above. Assume that if the
1041 CFA calculation is so complicated as to require a stack program
1042 that this will not be a problem. */
1044 const unsigned char *exp = fs->cfa_exp;
1047 exp = read_uleb128 (exp, &len);
1048 cfa = (void *) (_Unwind_Ptr)
1049 execute_stack_op (exp, exp + len, context, 0);
1058 /* Compute the addresses of all registers saved in this frame. */
1059 for (i = 0; i < DWARF_FRAME_REGISTERS + 1; ++i)
1060 switch (fs->regs.reg[i].how)
1064 case REG_SAVED_OFFSET:
1065 context->reg[i] = cfa + fs->regs.reg[i].loc.offset;
1068 context->reg[i] = orig_context.reg[fs->regs.reg[i].loc.reg];
1072 const unsigned char *exp = fs->regs.reg[i].loc.exp;
1076 exp = read_uleb128 (exp, &len);
1077 val = execute_stack_op (exp, exp + len, &orig_context,
1079 context->reg[i] = (void *) val;
1086 uw_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
1088 uw_update_context_1 (context, fs);
1090 /* Compute the return address now, since the return address column
1091 can change from frame to frame. */
1092 context->ra = __builtin_extract_return_addr
1093 ((void *) (_Unwind_Ptr) _Unwind_GetGR (context, fs->retaddr_column));
1096 /* Fill in CONTEXT for top-of-stack. The only valid registers at this
1097 level will be the return address and the CFA. */
1099 #define uw_init_context(CONTEXT) \
1101 /* Do any necessary initialization to access arbitrary stack frames. \
1102 On the SPARC, this means flushing the register windows. */ \
1103 __builtin_unwind_init (); \
1104 uw_init_context_1 (CONTEXT, __builtin_dwarf_cfa (), \
1105 __builtin_return_address (0)); \
1109 uw_init_context_1 (struct _Unwind_Context *context,
1110 void *outer_cfa, void *outer_ra)
1112 void *ra = __builtin_extract_return_addr (__builtin_return_address (0));
1113 _Unwind_FrameState fs;
1115 memset (context, 0, sizeof (struct _Unwind_Context));
1118 if (uw_frame_state_for (context, &fs) != _URC_NO_REASON)
1121 /* Force the frame state to use the known cfa value. */
1122 context->cfa = outer_cfa;
1123 fs.cfa_how = CFA_REG_OFFSET;
1127 uw_update_context_1 (context, &fs);
1129 /* If the return address column was saved in a register in the
1130 initialization context, then we can't see it in the given
1131 call frame data. So have the initialization context tell us. */
1132 context->ra = __builtin_extract_return_addr (outer_ra);
1136 /* Install TARGET into CURRENT so that we can return to it. This is a
1137 macro because __builtin_eh_return must be invoked in the context of
1140 #define uw_install_context(CURRENT, TARGET) \
1142 long offset = uw_install_context_1 ((CURRENT), (TARGET)); \
1143 void *handler = __builtin_frob_return_addr ((TARGET)->ra); \
1144 __builtin_eh_return (offset, handler); \
1148 init_dwarf_reg_size_table (void)
1150 __builtin_init_dwarf_reg_size_table (dwarf_reg_size_table);
1154 uw_install_context_1 (struct _Unwind_Context *current,
1155 struct _Unwind_Context *target)
1161 static __gthread_once_t once_regsizes = __GTHREAD_ONCE_INIT;
1162 if (__gthread_once (&once_regsizes, init_dwarf_reg_size_table) != 0
1163 || dwarf_reg_size_table[0] == 0)
1164 init_dwarf_reg_size_table ();
1167 if (dwarf_reg_size_table[0] == 0)
1168 init_dwarf_reg_size_table ();
1171 for (i = 0; i < DWARF_FRAME_REGISTERS; ++i)
1173 void *c = current->reg[i];
1174 void *t = target->reg[i];
1175 if (t && c && t != c)
1176 memcpy (c, t, dwarf_reg_size_table[i]);
1179 /* We adjust SP by the difference between CURRENT and TARGET's CFA. */
1180 if (STACK_GROWS_DOWNWARD)
1181 return target->cfa - current->cfa + target->args_size;
1183 return current->cfa - target->cfa - target->args_size;
1186 static inline _Unwind_Ptr
1187 uw_identify_context (struct _Unwind_Context *context)
1189 return _Unwind_GetIP (context);
1193 #include "unwind.inc"
1195 #endif /* !USING_SJLJ_EXCEPTIONS */