/* libunwind - a platform-independent unwind library

   Copyright (c) 2003, 2005 Hewlett-Packard Development Company, L.P.

        Contributed by David Mosberger-Tang <davidm@hpl.hp.com>

This file is part of libunwind.

Permission is hereby granted, free of charge, to any person obtaining

a copy of this software and associated documentation files (the

"Software"), to deal in the Software without restriction, including

without limitation the rights to use, copy, modify, merge, publish,

distribute, sublicense, and/or sell copies of the Software, and to

permit persons to whom the Software is furnished to do so, subject to

the following conditions:

The above copyright notice and this permission notice shall be

included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE

LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION

OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION

WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */

#include "dwarf_i.h"

#include "libunwind_i.h"

#include <stddef.h>

#include <limits.h>

#define alloc_reg_state()       (mempool_alloc (&dwarf_reg_state_pool))

#define free_reg_state(rs)      (mempool_free (&dwarf_reg_state_pool, rs))

#define DWARF_UNW_CACHE_SIZE(log_size)   (1 << log_size)

#define DWARF_UNW_HASH_SIZE(log_size)    (1 << (log_size + 1))

/* Read a register number that names the base register of the CFA.  The

   unwind cannot continue without it, so an unrepresentable one is fatal.  */

static inline int

read_cfa_regnum (unw_addr_space_t as, unw_accessors_t *a, unw_word_t *addr,

                 unw_word_t *valp, void *arg)

{

  int ret;

  if ((ret = dwarf_read_uleb128 (as, a, addr, valp, arg)) < 0)

    return ret;

  if (*valp >= DWARF_NUM_PRESERVED_REGS)

    {

      Debug (1, "Invalid CFA register number %u\n", (unsigned int) *valp);

      return -UNW_EBADREG;

    }

  return 0;

}

/* Read a register number that names a saved register.  A target need not

   have a slot for every register the producer describes, so the rule for

   one we cannot represent is dropped rather than failing the whole FDE.

   See set_savedreg().  */

static inline int

read_regnum (unw_addr_space_t as, unw_accessors_t *a, unw_word_t *addr,

             unw_word_t *valp, void *arg)

{

  return dwarf_read_uleb128 (as, a, addr, valp, arg);

}

static inline void

set_reg (dwarf_state_record_t *sr, unw_word_t regnum, dwarf_where_t where,

         unw_word_t val)

{

  sr->rs_current.reg.where[regnum] = where;

  sr->rs_current.reg.val[regnum] = val;

}

/* Record the rule for a saved register, ignoring registers this target has

   no slot for.  */

static inline void

set_savedreg (dwarf_state_record_t *sr, unw_word_t regnum, dwarf_where_t where,

              unw_word_t val)

{

  if (regnum >= DWARF_NUM_PRESERVED_REGS)

    {

      Debug (15, "ignoring rule for unrepresentable register r%lu\n",

             (long) regnum);

      return;

    }

  set_reg (sr, regnum, where, val);

}

/* Restore the rule a saved register had at the start of the FDE, ignoring

   registers this target has no slot for.  */

static inline void

restore_savedreg (dwarf_state_record_t *sr, unw_word_t regnum)

{

  if (regnum >= DWARF_NUM_PRESERVED_REGS)

    {

      Debug (15, "ignoring restore of unrepresentable register r%lu\n",

             (long) regnum);

      return;

    }

  sr->rs_current.reg.where[regnum] = sr->rs_initial.reg.where[regnum];

  sr->rs_current.reg.val[regnum] = sr->rs_initial.reg.val[regnum];

}

static inline int

push_rstate_stack(dwarf_stackable_reg_state_t **rs_stack)

{

  dwarf_stackable_reg_state_t *old_rs = *rs_stack;

  if (NULL == (*rs_stack = alloc_reg_state ()))

    {

      *rs_stack = old_rs;

      return -1;

    }

  (*rs_stack)->next = old_rs;

  return 0;

}

static inline void

pop_rstate_stack(dwarf_stackable_reg_state_t **rs_stack)

{

  dwarf_stackable_reg_state_t *old_rs = *rs_stack;

  *rs_stack = old_rs->next;

  free_reg_state (old_rs);

}

static inline void

empty_rstate_stack(dwarf_stackable_reg_state_t **rs_stack)

{

  while (*rs_stack)

    pop_rstate_stack(rs_stack);

}

#ifdef UNW_TARGET_AARCH64

static void

aarch64_negate_ra_sign_state(dwarf_state_record_t *sr);

#endif

/* Run a CFI program to update the register state.  */

static int

run_cfi_program (struct dwarf_cursor *c, dwarf_state_record_t *sr,

                 unw_word_t *ip, unw_word_t end_ip,

     unw_word_t *addr, unw_word_t end_addr,

     dwarf_stackable_reg_state_t **rs_stack,

                 struct dwarf_cie_info *dci)

{

  unw_addr_space_t as;

  void *arg;

  if (c->pi.flags & UNW_PI_FLAG_DEBUG_FRAME)

    {

      /* .debug_frame CFI is stored in local address space.  */

      as = unw_local_addr_space;

      arg = NULL;

    }

  else

    {

      as = c->as;

      arg = c->as_arg;

    }

  unw_accessors_t *a = unw_get_accessors_int (as);

  int ret = 0;

  while (*ip <= end_ip && *addr < end_addr && ret >= 0)

    {

      unw_word_t operand = 0, regnum, val, len;

      uint8_t u8, op;

      uint16_t u16;

      uint32_t u32;

      if ((ret = dwarf_readu8 (as, a, addr, &op, arg)) < 0)

        break;

      if (op & DWARF_CFA_OPCODE_MASK)

        {

          operand = op & DWARF_CFA_OPERAND_MASK;

          op &= ~DWARF_CFA_OPERAND_MASK;

        }

      switch ((dwarf_cfa_t) op)

        {

        case DW_CFA_advance_loc:

          *ip += operand * dci->code_align;

          Debug (15, "CFA_advance_loc to 0x%lx\n", (long) *ip);

          break;

        case DW_CFA_advance_loc1:

          if ((ret = dwarf_readu8 (as, a, addr, &u8, arg)) < 0)

            break;

          *ip += u8 * dci->code_align;

          Debug (15, "CFA_advance_loc1 to 0x%lx\n", (long) *ip);

          break;

        case DW_CFA_advance_loc2:

          if ((ret = dwarf_readu16 (as, a, addr, &u16, arg)) < 0)

            break;

          *ip += u16 * dci->code_align;

          Debug (15, "CFA_advance_loc2 to 0x%lx\n", (long) *ip);

          break;

        case DW_CFA_advance_loc4:

          if ((ret = dwarf_readu32 (as, a, addr, &u32, arg)) < 0)

            break;

          *ip += u32 * dci->code_align;

          Debug (15, "CFA_advance_loc4 to 0x%lx\n", (long) *ip);

          break;

        case DW_CFA_MIPS_advance_loc8:

#ifdef UNW_TARGET_MIPS

          {

            uint64_t u64 = 0;

            if ((ret = dwarf_readu64 (as, a, addr, &u64, arg)) < 0)

              break;

            *ip += u64 * dci->code_align;

            Debug (15, "CFA_MIPS_advance_loc8\n");

            break;

          }

#else

          Debug (1, "DW_CFA_MIPS_advance_loc8 on non-MIPS target\n");

          ret = -UNW_EINVAL;

          break;

#endif

        case DW_CFA_offset:

          regnum = operand;

          if ((ret = dwarf_read_uleb128 (as, a, addr, &val, arg)) < 0)

            break;

          set_savedreg (sr, regnum, DWARF_WHERE_CFAREL, val * dci->data_align);

          Debug (15, "CFA_offset r%lu at cfa+0x%lx\n",

                 (long) regnum, (long) (val * dci->data_align));

          break;

        case DW_CFA_offset_extended:

          if (((ret = read_regnum (as, a, addr, &regnum, arg)) < 0)

              || ((ret = dwarf_read_uleb128 (as, a, addr, &val, arg)) < 0))

            break;

          set_savedreg (sr, regnum, DWARF_WHERE_CFAREL, val * dci->data_align);

          Debug (15, "CFA_offset_extended r%lu at cf+0x%lx\n",

                 (long) regnum, (long) (val * dci->data_align));

          break;

        case DW_CFA_offset_extended_sf:

          if (((ret = read_regnum (as, a, addr, &regnum, arg)) < 0)

              || ((ret = dwarf_read_sleb128 (as, a, addr, &val, arg)) < 0))

            break;

          set_savedreg (sr, regnum, DWARF_WHERE_CFAREL, val * dci->data_align);

          Debug (15, "CFA_offset_extended_sf r%lu at cf+0x%lx\n",

                 (long) regnum, (long) (val * dci->data_align));

          break;

        case DW_CFA_restore:

          regnum = operand;

          restore_savedreg (sr, regnum);

          Debug (15, "CFA_restore r%lu\n", (long) regnum);

          break;

        case DW_CFA_restore_extended:

          if ((ret = dwarf_read_uleb128 (as, a, addr, &regnum, arg)) < 0)

            break;

          restore_savedreg (sr, regnum);

          Debug (15, "CFA_restore_extended r%lu\n", (long) regnum);

          break;

        case DW_CFA_nop:

          break;

        case DW_CFA_set_loc:

          if ((ret = dwarf_read_encoded_pointer (as, a, addr, dci->fde_encoding,

                                                 &c->pi, ip,

                                                 arg)) < 0)

            break;

          Debug (15, "CFA_set_loc to 0x%lx\n", (long) *ip);

          break;

        case DW_CFA_undefined:

          if ((ret = read_regnum (as, a, addr, &regnum, arg)) < 0)

            break;

          set_savedreg (sr, regnum, DWARF_WHERE_UNDEF, 0);

          Debug (15, "CFA_undefined r%lu\n", (long) regnum);

          break;

        case DW_CFA_same_value:

          if ((ret = read_regnum (as, a, addr, &regnum, arg)) < 0)

            break;

          set_savedreg (sr, regnum, DWARF_WHERE_SAME, 0);

          Debug (15, "CFA_same_value r%lu\n", (long) regnum);

          break;

        case DW_CFA_register:

          if (((ret = read_regnum (as, a, addr, &regnum, arg)) < 0)

              || ((ret = dwarf_read_uleb128 (as, a, addr, &val, arg)) < 0))

            break;

          set_savedreg (sr, regnum, DWARF_WHERE_REG, val);

          Debug (15, "CFA_register r%lu to r%lu\n", (long) regnum, (long) val);

          break;

        case DW_CFA_remember_state:

    if (push_rstate_stack(rs_stack) < 0)

      {

              Debug (1, "Out of memory in DW_CFA_remember_state\n");

              ret = -UNW_ENOMEM;

              break;

      }

          (*rs_stack)->state = sr->rs_current;

          Debug (15, "CFA_remember_state\n");

          break;

        case DW_CFA_restore_state:

          if (!*rs_stack)

            {

              Debug (1, "register-state stack underflow\n");

              ret = -UNW_EINVAL;

              break;

            }

          sr->rs_current = (*rs_stack)->state;

          pop_rstate_stack(rs_stack);

          Debug (15, "CFA_restore_state\n");

          break;

        case DW_CFA_def_cfa:

          if (((ret = read_cfa_regnum (as, a, addr, &regnum, arg)) < 0)

              || ((ret = dwarf_read_uleb128 (as, a, addr, &val, arg)) < 0))

            break;

          set_reg (sr, DWARF_CFA_REG_COLUMN, DWARF_WHERE_REG, regnum);

          set_reg (sr, DWARF_CFA_OFF_COLUMN, 0, val);   /* NOT factored! */

          Debug (15, "CFA_def_cfa r%lu+0x%lx\n", (long) regnum, (long) val);

          break;

        case DW_CFA_def_cfa_sf:

          if (((ret = read_cfa_regnum (as, a, addr, &regnum, arg)) < 0)

              || ((ret = dwarf_read_sleb128 (as, a, addr, &val, arg)) < 0))

            break;

          set_reg (sr, DWARF_CFA_REG_COLUMN, DWARF_WHERE_REG, regnum);

          set_reg (sr, DWARF_CFA_OFF_COLUMN, 0,

                   val * dci->data_align);              /* factored! */

          Debug (15, "CFA_def_cfa_sf r%lu+0x%lx\n",

                 (long) regnum, (long) (val * dci->data_align));

          break;

        case DW_CFA_def_cfa_register:

          if ((ret = read_cfa_regnum (as, a, addr, &regnum, arg)) < 0)

            break;

          set_reg (sr, DWARF_CFA_REG_COLUMN, DWARF_WHERE_REG, regnum);

          Debug (15, "CFA_def_cfa_register r%lu\n", (long) regnum);

          break;

        case DW_CFA_def_cfa_offset:

          if ((ret = dwarf_read_uleb128 (as, a, addr, &val, arg)) < 0)

            break;

          set_reg (sr, DWARF_CFA_OFF_COLUMN, 0, val);   /* NOT factored! */

          Debug (15, "CFA_def_cfa_offset 0x%lx\n", (long) val);

          break;

        case DW_CFA_def_cfa_offset_sf:

          if ((ret = dwarf_read_sleb128 (as, a, addr, &val, arg)) < 0)

            break;

          set_reg (sr, DWARF_CFA_OFF_COLUMN, 0,

                   val * dci->data_align);      /* factored! */

          Debug (15, "CFA_def_cfa_offset_sf 0x%lx\n",

                 (long) (val * dci->data_align));

          break;

        case DW_CFA_def_cfa_expression:

          /* Save the address of the DW_FORM_block for later evaluation. */

          set_reg (sr, DWARF_CFA_REG_COLUMN, DWARF_WHERE_EXPR, *addr);

          if ((ret = dwarf_read_uleb128 (as, a, addr, &len, arg)) < 0)

            break;

          Debug (15, "CFA_def_cfa_expr @ 0x%lx [%lu bytes]\n",

                 (long) *addr, (long) len);

          *addr += len;

          break;

        case DW_CFA_expression:

          if ((ret = read_regnum (as, a, addr, &regnum, arg)) < 0)

            break;

          /* Save the address of the DW_FORM_block for later evaluation. */

          set_savedreg (sr, regnum, DWARF_WHERE_EXPR, *addr);

          if ((ret = dwarf_read_uleb128 (as, a, addr, &len, arg)) < 0)

            break;

          Debug (15, "CFA_expression r%lu @ 0x%lx [%lu bytes]\n",

                 (long) regnum, (long) addr, (long) len);

          *addr += len;

          break;

        case DW_CFA_val_expression:

          if ((ret = read_regnum (as, a, addr, &regnum, arg)) < 0)

            break;

          /* Save the address of the DW_FORM_block for later evaluation. */

          set_savedreg (sr, regnum, DWARF_WHERE_VAL_EXPR, *addr);

          if ((ret = dwarf_read_uleb128 (as, a, addr, &len, arg)) < 0)

            break;

          Debug (15, "CFA_val_expression r%lu @ 0x%lx [%lu bytes]\n",

                 (long) regnum, (long) addr, (long) len);

          *addr += len;

          break;

        case DW_CFA_GNU_args_size:

          if ((ret = dwarf_read_uleb128 (as, a, addr, &val, arg)) < 0)

            break;

          sr->args_size = val;

          Debug (15, "CFA_GNU_args_size %lu\n", (long) val);

          break;

        case DW_CFA_GNU_negative_offset_extended:

          /* A comment in GCC says that this is obsoleted by

             DW_CFA_offset_extended_sf, but that it's used by older

             PowerPC code.  */

          if (((ret = read_regnum (as, a, addr, &regnum, arg)) < 0)

              || ((ret = dwarf_read_uleb128 (as, a, addr, &val, arg)) < 0))

            break;

          set_savedreg (sr, regnum, DWARF_WHERE_CFAREL, ~(val * dci->data_align) + 1);

          Debug (15, "CFA_GNU_negative_offset_extended cfa+0x%lx\n",

                 (long) (~(val * dci->data_align) + 1));

          break;

        case DW_CFA_GNU_window_save:

#ifdef UNW_TARGET_SPARC

          /* This is a special CFA to handle all 16 windowed registers

             on SPARC.  */

          for (regnum = 16; regnum < 32; ++regnum)

            set_savedreg (sr, regnum, DWARF_WHERE_CFAREL,

                     (regnum - 16) * sizeof (unw_word_t));

          Debug (15, "CFA_GNU_window_save\n");

          break;

#elif UNW_TARGET_AARCH64

          /* This is a specific opcode on aarch64, DW_CFA_AARCH64_negate_ra_state */

          Debug (15, "DW_CFA_AARCH64_negate_ra_state\n");

          aarch64_negate_ra_sign_state(sr);

          break;

#else

          /* FALL THROUGH */

#endif

        case DW_CFA_lo_user:

        case DW_CFA_hi_user:

          Debug (1, "Unexpected CFA opcode 0x%x\n", op);

          ret = -UNW_EINVAL;

          break;

        }

    }

  if (ret > 0)

    ret = 0;

  return ret;

}

static int

fetch_proc_info (struct dwarf_cursor *c, unw_word_t ip)

{

  int ret, dynamic = 1;

  /* The 'ip' can point either to the previous or next instruction

     depending on what type of frame we have: normal call or a place

     to resume execution (e.g. after signal frame).

     For a normal call frame we need to back up so we point within the

     call itself; this is important because a) the call might be the

     very last instruction of the function and the edge of the FDE,

     and b) so that run_cfi_program() runs locations up to the call

     but not more.

     For signal frame, we need to do the exact opposite and look

     up using the current 'ip' value.  That is where execution will

     continue, and it's important we get this right, as 'ip' could be

     right at the function entry and hence FDE edge, or at instruction

     that manipulates CFA (push/pop). */

  if (c->use_prev_instr)

    {

#if defined(__arm__)

      /* On arm, the least bit denotes thumb/arm mode, clear it. */

      ip &= ~(unw_word_t)0x1;

#endif

      --ip;

    }

  memset (&c->pi, 0, sizeof (c->pi));

  /* check dynamic info first --- it overrides everything else */

  ret = unwi_find_dynamic_proc_info (c->as, ip, &c->pi, 1,

                                     c->as_arg);

  if (ret == -UNW_ENOINFO)

    {

      dynamic = 0;

      if ((ret = tdep_find_proc_info (c, ip, 1)) < 0)

        return ret;

    }

  if (c->pi.format != UNW_INFO_FORMAT_DYNAMIC

      && c->pi.format != UNW_INFO_FORMAT_TABLE

      && c->pi.format != UNW_INFO_FORMAT_REMOTE_TABLE

#ifdef UNW_TARGET_ARM

      && c->pi.format != UNW_INFO_FORMAT_ARM_EXIDX

#endif

      )

    return -UNW_ENOINFO;

  c->pi_valid = 1;

  c->pi_is_dynamic = dynamic;

  /* Let system/machine-dependent code determine frame-specific attributes. */

  if (ret >= 0)

    tdep_fetch_frame (c, ip, 1);

  return ret;

}

static int

parse_dynamic (struct dwarf_cursor  *c UNUSED,

         unw_word_t            ip UNUSED,

               dwarf_state_record_t *sr UNUSED)

{

  Debug (1, "Not yet implemented\n");

  return -UNW_ENOINFO;

}

static inline void

put_unwind_info (struct dwarf_cursor *c, unw_proc_info_t *pi)

{

  if (c->pi_is_dynamic)

    unwi_put_dynamic_unwind_info (c->as, pi, c->as_arg);

  else if (pi->unwind_info && pi->format == UNW_INFO_FORMAT_TABLE)

    {

      mempool_free (&dwarf_cie_info_pool, pi->unwind_info);

      pi->unwind_info = NULL;

    }

  c->pi_valid = 0;

}

static inline int

setup_fde (struct dwarf_cursor *c, dwarf_state_record_t *sr)

{

  int i, ret;

  assert (c->pi_valid);

  memset (sr, 0, sizeof (*sr));

  for (i = 0; i < DWARF_NUM_PRESERVED_REGS + 2; ++i)

    set_reg (sr, i, DWARF_WHERE_SAME, 0);

#if !(defined(UNW_TARGET_MIPS) && _MIPS_SIM == _ABI64) \

    && !defined(UNW_TARGET_S390X)

  /* SP defaults to CFA. s390x excluded: CFA = R15+160, so this default gives

     caller's R15 = CFA instead of R15, breaking frameless functions like kill

     that never emit DW_CFA_offset for R15. */

  set_reg (sr, TDEP_DWARF_SP, DWARF_WHERE_CFA, 0);

#endif

  struct dwarf_cie_info *dci = c->pi.unwind_info;

  sr->rs_current.ret_addr_column  = dci->ret_addr_column;

  unw_word_t addr = dci->cie_instr_start;

  unw_word_t curr_ip = 0;

  dwarf_stackable_reg_state_t *rs_stack = NULL;

  ret = run_cfi_program (c, sr, &curr_ip, ~(unw_word_t) 0, &addr,

       dci->cie_instr_end,

       &rs_stack, dci);

  empty_rstate_stack(&rs_stack);

  if (ret < 0)

    return ret;

  memcpy (&sr->rs_initial, &sr->rs_current, sizeof (sr->rs_initial));

  return 0;

}

static inline int

parse_fde (struct dwarf_cursor *c, unw_word_t ip, dwarf_state_record_t *sr)

{

  int ret;

  struct dwarf_cie_info *dci = c->pi.unwind_info;

  unw_word_t addr = dci->fde_instr_start;

  unw_word_t curr_ip = c->pi.start_ip;

  dwarf_stackable_reg_state_t *rs_stack = NULL;

  /* Process up to current `ip` for signal frame and `ip - 1` for normal call frame

     See `c->use_prev_instr` use in `fetch_proc_info` for details. */

  ret = run_cfi_program (c, sr, &curr_ip, ip - c->use_prev_instr, &addr, dci->fde_instr_end,

       &rs_stack, dci);

  empty_rstate_stack(&rs_stack);

  if (ret < 0)

    return ret;

  return 0;

}

HIDDEN int

dwarf_flush_rs_cache (struct dwarf_rs_cache *cache)

{

  int i;

  if (cache->log_size == DWARF_DEFAULT_LOG_UNW_CACHE_SIZE

      || !cache->hash) {

    cache->hash = cache->default_hash;

    cache->buckets = cache->default_buckets;

    cache->links = cache->default_links;

    cache->log_size = DWARF_DEFAULT_LOG_UNW_CACHE_SIZE;

  } else {

    if (cache->hash && cache->hash != cache->default_hash)

      mi_munmap(cache->hash, DWARF_UNW_HASH_SIZE(cache->prev_log_size)

                              * sizeof (cache->hash[0]));

    if (cache->buckets && cache->buckets != cache->default_buckets)

      mi_munmap(cache->buckets, DWARF_UNW_CACHE_SIZE(cache->prev_log_size)

                              * sizeof (cache->buckets[0]));

    if (cache->links && cache->links != cache->default_links)

      mi_munmap(cache->links, DWARF_UNW_CACHE_SIZE(cache->prev_log_size)

                              * sizeof (cache->links[0]));

    GET_MEMORY(cache->hash, DWARF_UNW_HASH_SIZE(cache->log_size)

                             * sizeof (cache->hash[0]));

    GET_MEMORY(cache->buckets, DWARF_UNW_CACHE_SIZE(cache->log_size)

                                * sizeof (cache->buckets[0]));

    GET_MEMORY(cache->links, DWARF_UNW_CACHE_SIZE(cache->log_size)

                                * sizeof (cache->links[0]));

    if (!cache->hash || !cache->buckets || !cache->links)

      {

        Debug (1, "Unable to allocate cache memory");

        return -UNW_ENOMEM;

      }

    cache->prev_log_size = cache->log_size;

  }

  cache->rr_head = 0;

  for (i = 0; i < DWARF_UNW_CACHE_SIZE(cache->log_size); ++i)

    {

      cache->links[i].coll_chain = -1;

      cache->links[i].ip = 0;

      cache->links[i].valid = 0;

    }

  for (i = 0; i< DWARF_UNW_HASH_SIZE(cache->log_size); ++i)

    cache->hash[i] = -1;

  return 0;

}

static inline struct dwarf_rs_cache *

get_rs_cache (unw_addr_space_t as, intrmask_t *saved_maskp)

{

  struct dwarf_rs_cache *cache = &as->global_cache;

  unw_caching_policy_t caching = as->caching_policy;

  if (caching == UNW_CACHE_NONE)

    return NULL;

#if defined(HAVE___CACHE_PER_THREAD) && HAVE___CACHE_PER_THREAD

  if (likely (caching == UNW_CACHE_PER_THREAD))

    {

      static thread_local struct dwarf_rs_cache tls_cache __attribute__((tls_model("initial-exec")));

      Debug (16, "using TLS cache\n");

      cache = &tls_cache;

    }

  else

#else

  if (likely (caching == UNW_CACHE_GLOBAL))

#endif

    {

      Debug (16, "acquiring lock\n");

      lock_acquire (&cache->lock, *saved_maskp);

    }

  if ((atomic_load (&as->cache_generation) != atomic_load (&cache->generation))

       || !cache->hash)

    {

      /* cache_size is only set in the global_cache, copy it over before flushing */

      cache->log_size = as->global_cache.log_size;

      if (dwarf_flush_rs_cache (cache) < 0)

        return NULL;

      atomic_store (&cache->generation, atomic_load (&as->cache_generation));

    }

  return cache;

}

static inline void

put_rs_cache (unw_addr_space_t as, struct dwarf_rs_cache *cache,

                  intrmask_t *saved_maskp)

{

  assert (as->caching_policy != UNW_CACHE_NONE);

  Debug (16, "unmasking signals/interrupts and releasing lock\n");

  if (likely (as->caching_policy == UNW_CACHE_GLOBAL))

    lock_release (&cache->lock, *saved_maskp);

}

static inline unw_hash_index_t CONST_ATTR

hash (unw_word_t ip, unsigned short log_size)

{

  /* based on (sqrt(5)/2-1)*2^64 */

# define magic  ((unw_word_t) 0x9e3779b97f4a7c16ULL)

  return (unw_hash_index_t) (ip * magic >> ((sizeof(unw_word_t) * 8) - (log_size + 1)));

}

static inline long

cache_match (struct dwarf_rs_cache *cache, unsigned short index, unw_word_t ip)

{

  return (cache->links[index].valid && (ip == cache->links[index].ip));

}

static dwarf_reg_state_t *

rs_lookup (struct dwarf_rs_cache *cache, struct dwarf_cursor *c)

{

  unsigned short index;

  unw_word_t ip = c->ip;

  if (c->hint > 0)

    {

      index = c->hint - 1;

      if (cache_match (cache, index, ip))

  return &cache->buckets[index];

    }

  for (index = cache->hash[hash (ip, cache->log_size)];

       index < DWARF_UNW_CACHE_SIZE(cache->log_size);

       index = cache->links[index].coll_chain)

    {

      if (cache_match (cache, index, ip))

  return &cache->buckets[index];

    }

  return NULL;

}

static inline dwarf_reg_state_t *

rs_new (struct dwarf_rs_cache *cache, struct dwarf_cursor * c)

{

  unw_hash_index_t index;

  unsigned short head;

  head = cache->rr_head;

  cache->rr_head = (head + 1) & (DWARF_UNW_CACHE_SIZE(cache->log_size) - 1);

  /* remove the old rs from the hash table (if it's there): */

  if (cache->links[head].ip)

    {

      unsigned short *pindex;

      for (pindex = &cache->hash[hash (cache->links[head].ip, cache->log_size)];

     *pindex < DWARF_UNW_CACHE_SIZE(cache->log_size);

     pindex = &cache->links[*pindex].coll_chain)

  {

    if (*pindex == head)

      {

        *pindex = cache->links[*pindex].coll_chain;

        break;

      }

  }

    }

  /* enter new rs in the hash table */

  index = hash (c->ip, cache->log_size);

  cache->links[head].coll_chain = cache->hash[index];

  cache->hash[index] = head;

  cache->links[head].ip = c->ip;

  cache->links[head].valid = 1;

  cache->links[head].signal_frame = tdep_cache_frame(c) ? 1 : 0;

  cache->links[head].use_prev_instr = c->use_prev_instr;

  return cache->buckets + head;

}

static int

create_state_record_for (struct dwarf_cursor *c, dwarf_state_record_t *sr,

                         unw_word_t ip)

{

  int ret;

  switch (c->pi.format)

    {

    case UNW_INFO_FORMAT_TABLE:

    case UNW_INFO_FORMAT_REMOTE_TABLE:

      if ((ret = setup_fde(c, sr)) < 0)

  return ret;

      ret = parse_fde (c, ip, sr);

      break;

    case UNW_INFO_FORMAT_DYNAMIC:

      ret = parse_dynamic (c, ip, sr);

      break;

#ifdef UNW_TARGET_ARM

    case UNW_INFO_FORMAT_ARM_EXIDX:

      /* ARM exidx proc info is stepped by arm_exidx_step(), not the DWARF

         path; signal dwarf_step() to skip so the cursor is not advanced

         with an uninitialized state record. */

      ret = -UNW_ENOINFO;

      break;

#endif

    default:

      Debug (1, "Unexpected unwind-info format %d\n", c->pi.format);

      ret = -UNW_EINVAL;

    }

  return ret;

}

static inline int

eval_location_expr (struct dwarf_cursor *c, unw_word_t stack_val, unw_addr_space_t as,

                    unw_accessors_t *a, unw_word_t addr,

                    dwarf_loc_t *locp, void *arg)

{

  int ret, is_register;

  unw_word_t len, val;

  /* read the length of the expression: */

  if ((ret = dwarf_read_uleb128 (as, a, &addr, &len, arg)) < 0)

    return ret;

  /* evaluate the expression: */

  if ((ret = dwarf_eval_expr (c, stack_val, &addr, len, &val, &is_register)) < 0)

    return ret;

  if (is_register)

    *locp = DWARF_REG_LOC (c, dwarf_to_unw_regnum (val));

  else

    *locp = DWARF_MEM_LOC (c, val);

  return 0;

}

#ifdef UNW_TARGET_AARCH64

#include "libunwind-aarch64.h"

static void

aarch64_negate_ra_sign_state(dwarf_state_record_t *sr)

{

  unw_word_t ra_sign_state = sr->rs_current.reg.val[UNW_AARCH64_RA_SIGN_STATE];

  ra_sign_state ^= 0x1;

  set_reg(sr, UNW_AARCH64_RA_SIGN_STATE, DWARF_WHERE_SAME, ra_sign_state);

}

static unw_word_t

aarch64_get_ra_sign_state(struct dwarf_reg_state *rs)

{

   return rs->reg.val[UNW_AARCH64_RA_SIGN_STATE];

}

#endif

static int

apply_reg_state (struct dwarf_cursor *c, struct dwarf_reg_state *rs)

{

  unw_regnum_t regnum;

  unw_word_t addr, cfa, ip;

  unw_word_t prev_ip, prev_cfa;

  unw_addr_space_t as;

  dwarf_loc_t cfa_loc;

  unw_accessors_t *a;

  int i, ret;

  void *arg;

  /* In the case that we have incorrect CFI, the return address column may be

   * outside the valid range of data and will read invalid data.  Protect

   * against the errant read and indicate that we have a bad frame.  */

  if (rs->ret_addr_column >= DWARF_NUM_PRESERVED_REGS) {

    Dprintf ("%s: return address entry %zu is outside of range of CIE",

             __FUNCTION__, rs->ret_addr_column);

    return -UNW_EBADFRAME;

  }

  prev_ip = c->ip;

  prev_cfa = c->cfa;

  as = c->as;

  arg = c->as_arg;

  a = unw_get_accessors_int (as);

  /* Evaluate the CFA first, because it may be referred to by other

     expressions.  */

  if (rs->reg.where[DWARF_CFA_REG_COLUMN] == DWARF_WHERE_REG)

    {

      /* CFA is equal to [reg] + offset: */

      /* As a special-case, if the stack-pointer is the CFA and the

         stack-pointer wasn't saved, popping the CFA implicitly pops

         the stack-pointer as well.  */

      if ((rs->reg.val[DWARF_CFA_REG_COLUMN] == TDEP_DWARF_SP)

          && (TDEP_DWARF_SP < ARRAY_SIZE(rs->reg.val))

          && (DWARF_IS_NULL_LOC(c->loc[TDEP_DWARF_SP])))

          cfa = c->cfa;

      else

        {

          regnum = dwarf_to_unw_regnum ((unw_regnum_t) rs->reg.val[DWARF_CFA_REG_COLUMN]);

          if ((ret = unw_get_reg (dwarf_to_cursor(c), regnum, &cfa)) < 0)

            return ret;

        }

      cfa += rs->reg.val[DWARF_CFA_OFF_COLUMN];

    }

  else

    {

      /* CFA is equal to EXPR: */

      assert (rs->reg.where[DWARF_CFA_REG_COLUMN] == DWARF_WHERE_EXPR);

      addr = rs->reg.val[DWARF_CFA_REG_COLUMN];

      /* The dwarf standard doesn't specify an initial value to be pushed on */

      /* the stack before DW_CFA_def_cfa_expression evaluation. We push on a */

      /* dummy value (0) to keep the eval_location_expr function consistent. */

      if ((ret = eval_location_expr (c, 0, as, a, addr, &cfa_loc, arg)) < 0)

        return ret;

      /* the returned location better be a memory location... */

      if (DWARF_IS_REG_LOC (cfa_loc))

        return -UNW_EBADFRAME;

      cfa = DWARF_GET_LOC (cfa_loc);

    }

  dwarf_loc_t new_loc[DWARF_NUM_PRESERVED_REGS];

  memcpy(new_loc, c->loc, sizeof(new_loc));

  for (i = 0; i < DWARF_NUM_PRESERVED_REGS; ++i)

    {

      switch ((dwarf_where_t) rs->reg.where[i])

        {

        case DWARF_WHERE_UNDEF:

          new_loc[i] = DWARF_NULL_LOC;

          break;

        case DWARF_WHERE_SAME:

          break;

        case DWARF_WHERE_CFA:

          new_loc[i] = DWARF_VAL_LOC (c, cfa);

          break;

        case DWARF_WHERE_CFAREL:

          new_loc[i] = DWARF_MEM_LOC (c, cfa + rs->reg.val[i]);

          break;

        case DWARF_WHERE_REG:

#ifdef __s390x__

          /* GPRs can be saved in FPRs on s390x */

          if (unw_is_fpreg (dwarf_to_unw_regnum (rs->reg.val[i])))

            {

              new_loc[i] = DWARF_FPREG_LOC (c, dwarf_to_unw_regnum (rs->reg.val[i]));

              break;

            }

#endif

          new_loc[i] = new_loc[rs->reg.val[i]];

          break;

        case DWARF_WHERE_EXPR:

          addr = rs->reg.val[i];

          /* The dwarf standard requires the current CFA to be pushed on the */

          /* stack before DW_CFA_expression evaluation. */

          if ((ret = eval_location_expr (c, cfa, as, a, addr, new_loc + i, arg)) < 0)

            return ret;

          break;

        case DWARF_WHERE_VAL_EXPR:

          addr = rs->reg.val[i];

          /* The dwarf standard requires the current CFA to be pushed on the */

          /* stack before DW_CFA_val_expression evaluation. */

          if ((ret = eval_location_expr (c, cfa, as, a, addr, new_loc + i, arg)) < 0)

            return ret;

          new_loc[i] = DWARF_VAL_LOC (c, DWARF_GET_LOC (new_loc[i]));

          break;

        }

    }

  memcpy(c->loc, new_loc, sizeof(new_loc));

  c->cfa = cfa;

  /* DWARF spec says undefined return address location means end of stack. */

  if (DWARF_IS_NULL_LOC (c->loc[rs->ret_addr_column]))

    {

      c->ip = 0;

    }

  else

  {

    ret = dwarf_get (c, c->loc[rs->ret_addr_column], &ip);

    if (ret < 0)