libgcc/config/c6x/unwind-c6x.c

   1 /* C6X EABI compliant unwinding routines.
   2    Copyright (C) 2011-2021 Free Software Foundation, Inc.
   3
   4    This file is free software; you can redistribute it and/or modify it
   5    under the terms of the GNU General Public License as published by the
   6    Free Software Foundation; either version 3, or (at your option) any
   7    later version.
   8
   9    This file is distributed in the hope that it will be useful, but
  10    WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    General Public License for more details.
  13
  14    Under Section 7 of GPL version 3, you are granted additional
  15    permissions described in the GCC Runtime Library Exception, version
  16    3.1, as published by the Free Software Foundation.
  17
  18    You should have received a copy of the GNU General Public License and
  19    a copy of the GCC Runtime Library Exception along with this program;
  20    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  21    <http://www.gnu.org/licenses/>.  */
  22
  23 #include "unwind.h"
  24
  25 /* Misc constants.  */
  26 #define NUM_SAVED_REGS 32
  27 #define R_B0 16
  28 #define R_B3 (R_B0 + 3)
  29 #define R_B15 (R_B0 + 15)
  30 #define R_SP R_B15
  31 #define R_LR R_B3
  32 #define R_PC 33
  33
  34 #define VRS_PC(vrs) ((vrs)->core.pc)
  35 #define VRS_SP(vrs) ((vrs)->core.reg[R_SP])
  36 #define VRS_RETURN(vrs) ((vrs)->core.reg[R_B3])
  37
  38 struct core_regs
  39 {
  40   _uw reg[NUM_SAVED_REGS];
  41   _uw pc;
  42 };
  43
  44 typedef struct
  45 {
  46   /* The first fields must be the same as a phase2_vrs.  */
  47   _uw demand_save_flags; /* Currently always zero.  */
  48   struct core_regs core;
  49   _uw prev_sp; /* Only valid during forced unwinding.  */
  50 } phase1_vrs;
  51
  52 /* This must match the structure created by the assembly wrappers.  */
  53 typedef struct
  54 {
  55   _uw demand_save_flags;
  56   struct core_regs core;
  57 } phase2_vrs;
  58
  59 /* Coprocessor register state manipulation functions.  */
  60
  61 /* Restore coprocessor state after phase1 unwinding.  */
  62 static void
  63 restore_non_core_regs (phase1_vrs * vrs __attribute__((unused)))
  64 {
  65 }
  66
  67 #include "unwind-arm-common.inc"
  68
  69 /* ABI defined personality routines.  */
  70 extern _Unwind_Reason_Code __c6xabi_unwind_cpp_pr0 (_Unwind_State,
  71     _Unwind_Control_Block *, _Unwind_Context *);// __attribute__((weak));
  72 extern _Unwind_Reason_Code __c6xabi_unwind_cpp_pr1 (_Unwind_State,
  73     _Unwind_Control_Block *, _Unwind_Context *) __attribute__((weak));
  74 extern _Unwind_Reason_Code __c6xabi_unwind_cpp_pr2 (_Unwind_State,
  75     _Unwind_Control_Block *, _Unwind_Context *) __attribute__((weak));
  76 extern _Unwind_Reason_Code __c6xabi_unwind_cpp_pr3 (_Unwind_State,
  77     _Unwind_Control_Block *, _Unwind_Context *) __attribute__((weak));
  78 extern _Unwind_Reason_Code __c6xabi_unwind_cpp_pr4 (_Unwind_State,
  79     _Unwind_Control_Block *, _Unwind_Context *) __attribute__((weak));
  80
  81 /* ABI defined routine to store a virtual register to memory.  */
  82
  83 _Unwind_VRS_Result _Unwind_VRS_Get (_Unwind_Context *context,
  84                                     _Unwind_VRS_RegClass regclass,
  85                                     _uw regno,
  86                                     _Unwind_VRS_DataRepresentation representation,
  87                                     void *valuep)
  88 {
  89   phase1_vrs *vrs = (phase1_vrs *) context;
  90
  91   switch (regclass)
  92     {
  93     case _UVRSC_CORE:
  94       if (representation != _UVRSD_UINT32)
  95         return _UVRSR_FAILED;
  96       if (regno == R_PC)
  97         {
  98           *(_uw *) valuep = vrs->core.pc;
  99           return _UVRSR_OK;
 100         }
 101       if (regno >= NUM_SAVED_REGS)
 102         return _UVRSR_FAILED;
 103       *(_uw *) valuep = vrs->core.reg[regno];
 104       return _UVRSR_OK;
 105
 106     default:
 107       return _UVRSR_FAILED;
 108     }
 109 }
 110
 111
 112 /* ABI defined function to load a virtual register from memory.  */
 113
 114 _Unwind_VRS_Result _Unwind_VRS_Set (_Unwind_Context *context,
 115                                     _Unwind_VRS_RegClass regclass,
 116                                     _uw regno,
 117                                     _Unwind_VRS_DataRepresentation representation,
 118                                     void *valuep)
 119 {
 120   phase1_vrs *vrs = (phase1_vrs *) context;
 121
 122   switch (regclass)
 123     {
 124     case _UVRSC_CORE:
 125       if (representation != _UVRSD_UINT32)
 126         return _UVRSR_FAILED;
 127       if (regno == R_PC)
 128         {
 129           vrs->core.pc = *(_uw *) valuep;
 130           return _UVRSR_OK;
 131         }
 132       if (regno >= NUM_SAVED_REGS)
 133         return _UVRSR_FAILED;
 134
 135       vrs->core.reg[regno] = *(_uw *) valuep;
 136       return _UVRSR_OK;
 137
 138     default:
 139       return _UVRSR_FAILED;
 140     }
 141 }
 142
 143
 144 /* Core unwinding functions.  */
 145
 146 /* Calculate the address encoded by a 31-bit self-relative offset at address
 147    P.  */
 148 static inline _uw
 149 selfrel_offset31 (const _uw *p)
 150 {
 151   _uw offset;
 152
 153   offset = *p << 1;
 154   return offset + (_uw) p;
 155 }
 156
 157
 158 static _uw
 159 __gnu_unwind_get_pr_addr (int idx)
 160 {
 161   switch (idx)
 162     {
 163     case 0:
 164       return (_uw) &__c6xabi_unwind_cpp_pr0;
 165
 166     case 1:
 167       return (_uw) &__c6xabi_unwind_cpp_pr1;
 168
 169     case 2:
 170       return (_uw) &__c6xabi_unwind_cpp_pr2;
 171
 172     case 3:
 173       return (_uw) &__c6xabi_unwind_cpp_pr3;
 174
 175     case 4:
 176       return (_uw) &__c6xabi_unwind_cpp_pr4;
 177
 178     default:
 179        return 0;
 180     }
 181 }
 182
 183
 184 /* ABI defined personality routine entry points.  */
 185
 186 _Unwind_Reason_Code
 187 __c6xabi_unwind_cpp_pr0 (_Unwind_State state,
 188                         _Unwind_Control_Block *ucbp,
 189                         _Unwind_Context *context)
 190 {
 191   return __gnu_unwind_pr_common (state, ucbp, context, 0);
 192 }
 193
 194 _Unwind_Reason_Code
 195 __c6xabi_unwind_cpp_pr1 (_Unwind_State state,
 196                         _Unwind_Control_Block *ucbp,
 197                         _Unwind_Context *context)
 198 {
 199   return __gnu_unwind_pr_common (state, ucbp, context, 1);
 200 }
 201
 202 _Unwind_Reason_Code
 203 __c6xabi_unwind_cpp_pr2 (_Unwind_State state,
 204                         _Unwind_Control_Block *ucbp,
 205                         _Unwind_Context *context)
 206 {
 207   return __gnu_unwind_pr_common (state, ucbp, context, 2);
 208 }
 209
 210 _Unwind_Reason_Code
 211 __c6xabi_unwind_cpp_pr3 (_Unwind_State state,
 212                         _Unwind_Control_Block *ucbp,
 213                         _Unwind_Context *context)
 214 {
 215   return __gnu_unwind_pr_common (state, ucbp, context, 3);
 216 }
 217
 218 _Unwind_Reason_Code
 219 __c6xabi_unwind_cpp_pr4 (_Unwind_State state,
 220                         _Unwind_Control_Block *ucbp,
 221                         _Unwind_Context *context)
 222 {
 223   return __gnu_unwind_pr_common (state, ucbp, context, 4);
 224 }