Add libc++ and libc++abi to third-party.

third_party/libc++abi/src/Unwind/DwarfInstructions.hpp

Index: third_party/libc++abi/src/Unwind/DwarfInstructions.hpp
===================================================================
--- third_party/libc++abi/src/Unwind/DwarfInstructions.hpp	(revision 0)
+++ third_party/libc++abi/src/Unwind/DwarfInstructions.hpp	(revision 0)
@@ -0,0 +1,888 @@
+//===-------------------------- DwarfInstructions.hpp ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//
+//  Processor specific interpretation of dwarf unwind info.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __DWARF_INSTRUCTIONS_HPP__
+#define __DWARF_INSTRUCTIONS_HPP__
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "dwarf2.h"
+#include "AddressSpace.hpp"
+#include "Registers.hpp"
+#include "DwarfParser.hpp"
+#include "config.h"
+
+
+namespace libunwind {
+
+
+/// DwarfInstructions maps abtract dwarf unwind instructions to a particular
+/// architecture
+template <typename A, typename R>
+class DwarfInstructions {
+public:
+  typedef typename A::pint_t pint_t;
+  typedef typename A::sint_t sint_t;
+
+  static int stepWithDwarf(A &addressSpace, pint_t pc, pint_t fdeStart,
+                           R &registers);
+
+private:
+
+  enum {
+    DW_X86_64_RET_ADDR = 16
+  };
+
+  enum {
+    DW_X86_RET_ADDR = 8
+  };
+
+  typedef typename CFI_Parser<A>::RegisterLocation  RegisterLocation;
+  typedef typename CFI_Parser<A>::PrologInfo        PrologInfo;
+  typedef typename CFI_Parser<A>::FDE_Info          FDE_Info;
+  typedef typename CFI_Parser<A>::CIE_Info          CIE_Info;
+
+  static pint_t evaluateExpression(pint_t expression, A &addressSpace,
+                                   const R &registers,
+                                   pint_t initialStackValue);
+  static pint_t getSavedRegister(A &addressSpace, const R &registers,
+                                 pint_t cfa, const RegisterLocation &savedReg);
+  static double getSavedFloatRegister(A &addressSpace, const R &registers,
+                                  pint_t cfa, const RegisterLocation &savedReg);
+  static v128 getSavedVectorRegister(A &addressSpace, const R &registers,
+                                  pint_t cfa, const RegisterLocation &savedReg);
+
+  // x86 specific variants
+  static int lastRestoreReg(const Registers_x86 &);
+  static bool isReturnAddressRegister(int regNum, const Registers_x86 &);
+  static pint_t getCFA(A &addressSpace, const PrologInfo &prolog,
+                       const Registers_x86 &);
+
+  // x86_64 specific variants
+  static int lastRestoreReg(const Registers_x86_64 &);
+  static bool isReturnAddressRegister(int regNum, const Registers_x86_64 &);
+  static pint_t getCFA(A &addressSpace,
+                       const PrologInfo &prolog,
+                       const Registers_x86_64 &);
+
+  // ppc specific variants
+  static int lastRestoreReg(const Registers_ppc &);
+  static bool isReturnAddressRegister(int regNum, const Registers_ppc &);
+  static pint_t getCFA(A &addressSpace,
+                       const PrologInfo &prolog,
+                       const Registers_ppc &);
+
+  // arm64 specific variants
+  static bool isReturnAddressRegister(int regNum, const Registers_arm64 &);
+  static int lastRestoreReg(const Registers_arm64 &);
+  static pint_t getCFA(A &addressSpace,
+                       const PrologInfo &prolog,
+                       const Registers_arm64 &);
+
+};
+
+
+template <typename A, typename R>
+typename A::pint_t DwarfInstructions<A, R>::getSavedRegister(
+    A &addressSpace, const R &registers, pint_t cfa,
+    const RegisterLocation &savedReg) {
+  switch (savedReg.location) {
+  case CFI_Parser<A>::kRegisterInCFA:
+    return addressSpace.getP(cfa + (pint_t)savedReg.value);
+
+  case CFI_Parser<A>::kRegisterAtExpression:
+    return addressSpace.getP(
+        evaluateExpression((pint_t)savedReg.value, addressSpace,
+                            registers, cfa));
+
+  case CFI_Parser<A>::kRegisterIsExpression:
+    return evaluateExpression((pint_t)savedReg.value, addressSpace,
+                              registers, cfa);
+
+  case CFI_Parser<A>::kRegisterInRegister:
+    return registers.getRegister((int)savedReg.value);
+
+  case CFI_Parser<A>::kRegisterUnused:
+  case CFI_Parser<A>::kRegisterOffsetFromCFA:
+    // FIX ME
+    break;
+  }
+  _LIBUNWIND_ABORT("unsupported restore location for register");
+}
+
+template <typename A, typename R>
+double DwarfInstructions<A, R>::getSavedFloatRegister(
+    A &addressSpace, const R &registers, pint_t cfa,
+    const RegisterLocation &savedReg) {
+  switch (savedReg.location) {
+  case CFI_Parser<A>::kRegisterInCFA:
+    return addressSpace.getDouble(cfa + (pint_t)savedReg.value);
+
+  case CFI_Parser<A>::kRegisterAtExpression:
+    return addressSpace.getDouble(
+        evaluateExpression((pint_t)savedReg.value, addressSpace,
+                            registers, cfa));
+
+  case CFI_Parser<A>::kRegisterIsExpression:
+  case CFI_Parser<A>::kRegisterUnused:
+  case CFI_Parser<A>::kRegisterOffsetFromCFA:
+  case CFI_Parser<A>::kRegisterInRegister:
+    // FIX ME
+    break;
+  }
+  _LIBUNWIND_ABORT("unsupported restore location for float register");
+}
+
+template <typename A, typename R>
+v128 DwarfInstructions<A, R>::getSavedVectorRegister(
+    A &addressSpace, const R &registers, pint_t cfa,
+    const RegisterLocation &savedReg) {
+  switch (savedReg.location) {
+  case CFI_Parser<A>::kRegisterInCFA:
+    return addressSpace.getVector(cfa + (pint_t)savedReg.value);
+
+  case CFI_Parser<A>::kRegisterAtExpression:
+    return addressSpace.getVector(
+        evaluateExpression((pint_t)savedReg.value, addressSpace,
+                            registers, cfa));
+
+  case CFI_Parser<A>::kRegisterIsExpression:
+  case CFI_Parser<A>::kRegisterUnused:
+  case CFI_Parser<A>::kRegisterOffsetFromCFA:
+  case CFI_Parser<A>::kRegisterInRegister:
+    // FIX ME
+    break;
+  }
+  _LIBUNWIND_ABORT("unsupported restore location for vector register");
+}
+
+template <typename A, typename R>
+int DwarfInstructions<A, R>::stepWithDwarf(A &addressSpace, pint_t pc,
+                                           pint_t fdeStart, R &registers) {
+  FDE_Info fdeInfo;
+  CIE_Info cieInfo;
+  if (CFI_Parser<A>::decodeFDE(addressSpace, fdeStart,
+                                                  &fdeInfo, &cieInfo) == NULL) {
+    PrologInfo prolog;
+    if (CFI_Parser<A>::parseFDEInstructions(addressSpace, fdeInfo, cieInfo, pc,
+                                                                     &prolog)) {
+      R newRegisters = registers;
+
+      // get pointer to cfa (architecture specific)
+      pint_t cfa = getCFA(addressSpace, prolog, registers);
+
+      // restore registers that dwarf says were saved
+      pint_t returnAddress = 0;
+      for (int i = 0; i <= lastRestoreReg(newRegisters); ++i) {
+        if (prolog.savedRegisters[i].location !=
+            CFI_Parser<A>::kRegisterUnused) {
+          if (registers.validFloatRegister(i))
+            newRegisters.setFloatRegister(
+                i, getSavedFloatRegister(addressSpace, registers, cfa,
+                                         prolog.savedRegisters[i]));
+          else if (registers.validVectorRegister(i))
+            newRegisters.setVectorRegister(
+                i, getSavedVectorRegister(addressSpace, registers, cfa,
+                                          prolog.savedRegisters[i]));
+          else if (isReturnAddressRegister(i, registers))
+            returnAddress = getSavedRegister(addressSpace, registers, cfa,
+                                             prolog.savedRegisters[i]);
+          else if (registers.validRegister(i))
+            newRegisters.setRegister(
+                i, getSavedRegister(addressSpace, registers, cfa,
+                                    prolog.savedRegisters[i]));
+          else
+            return UNW_EBADREG;
+        }
+      }
+
+      // By definition, the CFA is the stack pointer at the call site, so
+      // restoring SP means setting it to CFA.
+      newRegisters.setSP(cfa);
+
+      // Return address is address after call site instruction, so setting IP to
+      // that does simualates a return.
+      newRegisters.setIP(returnAddress);
+
+      // Simulate the step by replacing the register set with the new ones.
+      registers = newRegisters;
+
+      return UNW_STEP_SUCCESS;
+    }
+  }
+  return UNW_EBADFRAME;
+}
+
+template <typename A, typename R>
+typename A::pint_t
+DwarfInstructions<A, R>::evaluateExpression(pint_t expression, A &addressSpace,
+                                            const R &registers,
+                                            pint_t initialStackValue) {
+  const bool log = false;
+  pint_t p = expression;
+  pint_t expressionEnd = expression + 20; // temp, until len read
+  pint_t length = (pint_t)addressSpace.getULEB128(p, expressionEnd);
+  expressionEnd = p + length;
+  if (log)
+    fprintf(stderr, "evaluateExpression(): length=%llu\n", (uint64_t)length);
+  pint_t stack[100];
+  pint_t *sp = stack;
+  *(++sp) = initialStackValue;
+
+  while (p < expressionEnd) {
+    if (log) {
+      for (pint_t *t = sp; t > stack; --t) {
+        fprintf(stderr, "sp[] = 0x%llX\n", (uint64_t)(*t));
+      }
+    }
+    uint8_t opcode = addressSpace.get8(p++);
+    sint_t svalue, svalue2;
+    pint_t value;
+    uint32_t reg;
+    switch (opcode) {
+    case DW_OP_addr:
+      // push immediate address sized value
+      value = addressSpace.getP(p);
+      p += sizeof(pint_t);
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "push 0x%llX\n", (uint64_t) value);
+      break;
+
+    case DW_OP_deref:
+      // pop stack, dereference, push result
+      value = *sp--;
+      *(++sp) = addressSpace.getP(value);
+      if (log)
+        fprintf(stderr, "dereference 0x%llX\n", (uint64_t) value);
+      break;
+
+    case DW_OP_const1u:
+      // push immediate 1 byte value
+      value = addressSpace.get8(p);
+      p += 1;
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "push 0x%llX\n", (uint64_t) value);
+      break;
+
+    case DW_OP_const1s:
+      // push immediate 1 byte signed value
+      svalue = (int8_t) addressSpace.get8(p);
+      p += 1;
+      *(++sp) = (pint_t)svalue;
+      if (log)
+        fprintf(stderr, "push 0x%llX\n", (uint64_t) svalue);
+      break;
+
+    case DW_OP_const2u:
+      // push immediate 2 byte value
+      value = addressSpace.get16(p);
+      p += 2;
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "push 0x%llX\n", (uint64_t) value);
+      break;
+
+    case DW_OP_const2s:
+      // push immediate 2 byte signed value
+      svalue = (int16_t) addressSpace.get16(p);
+      p += 2;
+      *(++sp) = (pint_t)svalue;
+      if (log)
+        fprintf(stderr, "push 0x%llX\n", (uint64_t) svalue);
+      break;
+
+    case DW_OP_const4u:
+      // push immediate 4 byte value
+      value = addressSpace.get32(p);
+      p += 4;
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "push 0x%llX\n", (uint64_t) value);
+      break;
+
+    case DW_OP_const4s:
+      // push immediate 4 byte signed value
+      svalue = (int32_t)addressSpace.get32(p);
+      p += 4;
+      *(++sp) = (pint_t)svalue;
+      if (log)
+        fprintf(stderr, "push 0x%llX\n", (uint64_t) svalue);
+      break;
+
+    case DW_OP_const8u:
+      // push immediate 8 byte value
+      value = (pint_t)addressSpace.get64(p);
+      p += 8;
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "push 0x%llX\n", (uint64_t) value);
+      break;
+
+    case DW_OP_const8s:
+      // push immediate 8 byte signed value
+      value = (pint_t)addressSpace.get64(p);
+      p += 8;
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "push 0x%llX\n", (uint64_t) value);
+      break;
+
+    case DW_OP_constu:
+      // push immediate ULEB128 value
+      value = (pint_t)addressSpace.getULEB128(p, expressionEnd);
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "push 0x%llX\n", (uint64_t) value);
+      break;
+
+    case DW_OP_consts:
+      // push immediate SLEB128 value
+      svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
+      *(++sp) = (pint_t)svalue;
+      if (log)
+        fprintf(stderr, "push 0x%llX\n", (uint64_t) svalue);
+      break;
+
+    case DW_OP_dup:
+      // push top of stack
+      value = *sp;
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "duplicate top of stack\n");
+      break;
+
+    case DW_OP_drop:
+      // pop
+      --sp;
+      if (log)
+        fprintf(stderr, "pop top of stack\n");
+      break;
+
+    case DW_OP_over:
+      // dup second
+      value = sp[-1];
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "duplicate second in stack\n");
+      break;
+
+    case DW_OP_pick:
+      // pick from
+      reg = addressSpace.get8(p);
+      p += 1;
+      value = sp[-reg];
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "duplicate %d in stack\n", reg);
+      break;
+
+    case DW_OP_swap:
+      // swap top two
+      value = sp[0];
+      sp[0] = sp[-1];
+      sp[-1] = value;
+      if (log)
+        fprintf(stderr, "swap top of stack\n");
+      break;
+
+    case DW_OP_rot:
+      // rotate top three
+      value = sp[0];
+      sp[0] = sp[-1];
+      sp[-1] = sp[-2];
+      sp[-2] = value;
+      if (log)
+        fprintf(stderr, "rotate top three of stack\n");
+      break;
+
+    case DW_OP_xderef:
+      // pop stack, dereference, push result
+      value = *sp--;
+      *sp = *((pint_t*)value);
+      if (log)
+        fprintf(stderr, "x-dereference 0x%llX\n", (uint64_t) value);
+      break;
+
+    case DW_OP_abs:
+      svalue = (sint_t)*sp;
+      if (svalue < 0)
+        *sp = (pint_t)(-svalue);
+      if (log)
+        fprintf(stderr, "abs\n");
+      break;
+
+    case DW_OP_and:
+      value = *sp--;
+      *sp &= value;
+      if (log)
+        fprintf(stderr, "and\n");
+      break;
+
+    case DW_OP_div:
+      svalue = (sint_t)(*sp--);
+      svalue2 = (sint_t)*sp;
+      *sp = (pint_t)(svalue2 / svalue);
+      if (log)
+        fprintf(stderr, "div\n");
+      break;
+
+    case DW_OP_minus:
+      value = *sp--;
+      *sp = *sp - value;
+      if (log)
+        fprintf(stderr, "minus\n");
+      break;
+
+    case DW_OP_mod:
+      svalue = (sint_t)(*sp--);
+      svalue2 = (sint_t)*sp;
+      *sp = (pint_t)(svalue2 % svalue);
+      if (log)
+        fprintf(stderr, "module\n");
+      break;
+
+    case DW_OP_mul:
+      svalue = (sint_t)(*sp--);
+      svalue2 = (sint_t)*sp;
+      *sp = (pint_t)(svalue2 * svalue);
+      if (log)
+        fprintf(stderr, "mul\n");
+      break;
+
+    case DW_OP_neg:
+      *sp = 0 - *sp;
+      if (log)
+        fprintf(stderr, "neg\n");
+      break;
+
+    case DW_OP_not:
+      svalue = (sint_t)(*sp);
+      *sp = (pint_t)(~svalue);
+      if (log)
+        fprintf(stderr, "not\n");
+      break;
+
+    case DW_OP_or:
+      value = *sp--;
+      *sp |= value;
+      if (log)
+        fprintf(stderr, "or\n");
+      break;
+
+    case DW_OP_plus:
+      value = *sp--;
+      *sp += value;
+      if (log)
+        fprintf(stderr, "plus\n");
+      break;
+
+    case DW_OP_plus_uconst:
+      // pop stack, add uelb128 constant, push result
+      *sp += addressSpace.getULEB128(p, expressionEnd);
+      if (log)
+        fprintf(stderr, "add constant\n");
+      break;
+
+    case DW_OP_shl:
+      value = *sp--;
+      *sp = *sp << value;
+      if (log)
+        fprintf(stderr, "shift left\n");
+      break;
+
+    case DW_OP_shr:
+      value = *sp--;
+      *sp = *sp >> value;
+      if (log)
+        fprintf(stderr, "shift left\n");
+      break;
+
+    case DW_OP_shra:
+      value = *sp--;
+      svalue = (sint_t)*sp;
+      *sp = (pint_t)(svalue >> value);
+      if (log)
+        fprintf(stderr, "shift left arithmetric\n");
+      break;
+
+    case DW_OP_xor:
+      value = *sp--;
+      *sp ^= value;
+      if (log)
+        fprintf(stderr, "xor\n");
+      break;
+
+    case DW_OP_skip:
+      svalue = (int16_t) addressSpace.get16(p);
+      p += 2;
+      p = (pint_t)((sint_t)p + svalue);
+      if (log)
+        fprintf(stderr, "skip %lld\n", (uint64_t) svalue);
+      break;
+
+    case DW_OP_bra:
+      svalue = (int16_t) addressSpace.get16(p);
+      p += 2;
+      if (*sp--)
+        p = (pint_t)((sint_t)p + svalue);
+      if (log)
+        fprintf(stderr, "bra %lld\n", (uint64_t) svalue);
+      break;
+
+    case DW_OP_eq:
+      value = *sp--;
+      *sp = (*sp == value);
+      if (log)
+        fprintf(stderr, "eq\n");
+      break;
+
+    case DW_OP_ge:
+      value = *sp--;
+      *sp = (*sp >= value);
+      if (log)
+        fprintf(stderr, "ge\n");
+      break;
+
+    case DW_OP_gt:
+      value = *sp--;
+      *sp = (*sp > value);
+      if (log)
+        fprintf(stderr, "gt\n");
+      break;
+
+    case DW_OP_le:
+      value = *sp--;
+      *sp = (*sp <= value);
+      if (log)
+        fprintf(stderr, "le\n");
+      break;
+
+    case DW_OP_lt:
+      value = *sp--;
+      *sp = (*sp < value);
+      if (log)
+        fprintf(stderr, "lt\n");
+      break;
+
+    case DW_OP_ne:
+      value = *sp--;
+      *sp = (*sp != value);
+      if (log)
+        fprintf(stderr, "ne\n");
+      break;
+
+    case DW_OP_lit0:
+    case DW_OP_lit1:
+    case DW_OP_lit2:
+    case DW_OP_lit3:
+    case DW_OP_lit4:
+    case DW_OP_lit5:
+    case DW_OP_lit6:
+    case DW_OP_lit7:
+    case DW_OP_lit8:
+    case DW_OP_lit9:
+    case DW_OP_lit10:
+    case DW_OP_lit11:
+    case DW_OP_lit12:
+    case DW_OP_lit13:
+    case DW_OP_lit14:
+    case DW_OP_lit15:
+    case DW_OP_lit16:
+    case DW_OP_lit17:
+    case DW_OP_lit18:
+    case DW_OP_lit19:
+    case DW_OP_lit20:
+    case DW_OP_lit21:
+    case DW_OP_lit22:
+    case DW_OP_lit23:
+    case DW_OP_lit24:
+    case DW_OP_lit25:
+    case DW_OP_lit26:
+    case DW_OP_lit27:
+    case DW_OP_lit28:
+    case DW_OP_lit29:
+    case DW_OP_lit30:
+    case DW_OP_lit31:
+      value = opcode - DW_OP_lit0;
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "push literal 0x%llX\n", (uint64_t) value);
+      break;
+
+    case DW_OP_reg0:
+    case DW_OP_reg1:
+    case DW_OP_reg2:
+    case DW_OP_reg3:
+    case DW_OP_reg4:
+    case DW_OP_reg5:
+    case DW_OP_reg6:
+    case DW_OP_reg7:
+    case DW_OP_reg8:
+    case DW_OP_reg9:
+    case DW_OP_reg10:
+    case DW_OP_reg11:
+    case DW_OP_reg12:
+    case DW_OP_reg13:
+    case DW_OP_reg14:
+    case DW_OP_reg15:
+    case DW_OP_reg16:
+    case DW_OP_reg17:
+    case DW_OP_reg18:
+    case DW_OP_reg19:
+    case DW_OP_reg20:
+    case DW_OP_reg21:
+    case DW_OP_reg22:
+    case DW_OP_reg23:
+    case DW_OP_reg24:
+    case DW_OP_reg25:
+    case DW_OP_reg26:
+    case DW_OP_reg27:
+    case DW_OP_reg28:
+    case DW_OP_reg29:
+    case DW_OP_reg30:
+    case DW_OP_reg31:
+      reg = opcode - DW_OP_reg0;
+      *(++sp) = registers.getRegister((int)reg);
+      if (log)
+        fprintf(stderr, "push reg %d\n", reg);
+      break;
+
+    case DW_OP_regx:
+      reg = (uint32_t)addressSpace.getULEB128(p, expressionEnd);
+      *(++sp) = registers.getRegister((int)reg);
+      if (log)
+        fprintf(stderr, "push reg %d + 0x%llX\n", reg, (uint64_t) svalue);
+      break;
+
+    case DW_OP_breg0:
+    case DW_OP_breg1:
+    case DW_OP_breg2:
+    case DW_OP_breg3:
+    case DW_OP_breg4:
+    case DW_OP_breg5:
+    case DW_OP_breg6:
+    case DW_OP_breg7:
+    case DW_OP_breg8:
+    case DW_OP_breg9:
+    case DW_OP_breg10:
+    case DW_OP_breg11:
+    case DW_OP_breg12:
+    case DW_OP_breg13:
+    case DW_OP_breg14:
+    case DW_OP_breg15:
+    case DW_OP_breg16:
+    case DW_OP_breg17:
+    case DW_OP_breg18:
+    case DW_OP_breg19:
+    case DW_OP_breg20:
+    case DW_OP_breg21:
+    case DW_OP_breg22:
+    case DW_OP_breg23:
+    case DW_OP_breg24:
+    case DW_OP_breg25:
+    case DW_OP_breg26:
+    case DW_OP_breg27:
+    case DW_OP_breg28:
+    case DW_OP_breg29:
+    case DW_OP_breg30:
+    case DW_OP_breg31:
+      reg = opcode - DW_OP_breg0;
+      svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
+      svalue += registers.getRegister((int)reg);
+      *(++sp) = (pint_t)(svalue);
+      if (log)
+        fprintf(stderr, "push reg %d + 0x%llX\n", reg, (uint64_t) svalue);
+      break;
+
+    case DW_OP_bregx:
+      reg = (uint32_t)addressSpace.getULEB128(p, expressionEnd);
+      svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
+      svalue += registers.getRegister((int)reg);
+      *(++sp) = (pint_t)(svalue);
+      if (log)
+        fprintf(stderr, "push reg %d + 0x%llX\n", reg, (uint64_t) svalue);
+      break;
+
+    case DW_OP_fbreg:
+      _LIBUNWIND_ABORT("DW_OP_fbreg not implemented");
+      break;
+
+    case DW_OP_piece:
+      _LIBUNWIND_ABORT("DW_OP_piece not implemented");
+      break;
+
+    case DW_OP_deref_size:
+      // pop stack, dereference, push result
+      value = *sp--;
+      switch (addressSpace.get8(p++)) {
+      case 1:
+        value = addressSpace.get8(value);
+        break;
+      case 2:
+        value = addressSpace.get16(value);
+        break;
+      case 4:
+        value = addressSpace.get32(value);
+        break;
+      case 8:
+        value = (pint_t)addressSpace.get64(value);
+        break;
+      default:
+        _LIBUNWIND_ABORT("DW_OP_deref_size with bad size");
+      }
+      *(++sp) = value;
+      if (log)
+        fprintf(stderr, "sized dereference 0x%llX\n", (uint64_t) value);
+      break;
+
+    case DW_OP_xderef_size:
+    case DW_OP_nop:
+    case DW_OP_push_object_addres:
+    case DW_OP_call2:
+    case DW_OP_call4:
+    case DW_OP_call_ref:
+    default:
+      _LIBUNWIND_ABORT("dwarf opcode not implemented");
+    }
+
+  }
+  if (log)
+    fprintf(stderr, "expression evaluates to 0x%llX\n", (uint64_t) * sp);
+  return *sp;
+}
+
+//
+//  x86_64 specific functions
+//
+template <typename A, typename R>
+int DwarfInstructions<A, R>::lastRestoreReg(const Registers_x86_64 &) {
+  static_assert((int)CFI_Parser<A>::kMaxRegisterNumber
+              > (int)DW_X86_64_RET_ADDR, "register number out of range");
+  return DW_X86_64_RET_ADDR;
+}
+
+template <typename A, typename R>
+bool
+DwarfInstructions<A, R>::isReturnAddressRegister(int regNum,
+                                                 const Registers_x86_64 &) {
+  return (regNum == DW_X86_64_RET_ADDR);
+}
+
+template <typename A, typename R>
+typename A::pint_t DwarfInstructions<A, R>::getCFA(
+    A &addressSpace, const PrologInfo &prolog,
+    const Registers_x86_64 &registers) {
+  if (prolog.cfaRegister != 0)
+    return (pint_t)((sint_t)registers.getRegister((int)prolog.cfaRegister)
+                                                    + prolog.cfaRegisterOffset);
+  else if (prolog.cfaExpression != 0)
+    return evaluateExpression((pint_t)prolog.cfaExpression, addressSpace, registers, 0);
+  else
+    _LIBUNWIND_ABORT("getCFA(): unknown location for x86_64 cfa");
+}
+
+
+//
+//  x86 specific functions
+//
+template <typename A, typename R>
+int DwarfInstructions<A, R>::lastRestoreReg(const Registers_x86 &) {
+  static_assert((int)CFI_Parser<A>::kMaxRegisterNumber
+              > (int)DW_X86_RET_ADDR, "register number out of range");
+  return DW_X86_RET_ADDR;
+}
+
+template <typename A, typename R>
+bool DwarfInstructions<A, R>::isReturnAddressRegister(int regNum,
+                                                      const Registers_x86 &) {
+  return (regNum == DW_X86_RET_ADDR);
+}
+
+template <typename A, typename R>
+typename A::pint_t DwarfInstructions<A, R>::getCFA(
+    A &addressSpace, const PrologInfo &prolog,
+    const Registers_x86 &registers) {
+  if (prolog.cfaRegister != 0)
+    return (pint_t)((sint_t)registers.getRegister((int)prolog.cfaRegister)
+                                                    + prolog.cfaRegisterOffset);
+  else if (prolog.cfaExpression != 0)
+    return evaluateExpression((pint_t)prolog.cfaExpression, addressSpace,
+                                                                  registers, 0);
+  else
+    _LIBUNWIND_ABORT("getCFA(): unknown location for x86 cfa");
+}
+
+
+//
+//  ppc specific functions
+//
+template <typename A, typename R>
+int DwarfInstructions<A, R>::lastRestoreReg(const Registers_ppc &) {
+  static_assert((int)CFI_Parser<A>::kMaxRegisterNumber
+              > (int)UNW_PPC_SPEFSCR, "register number out of range");
+  return UNW_PPC_SPEFSCR;
+}
+
+template <typename A, typename R>
+bool DwarfInstructions<A, R>::isReturnAddressRegister(int regNum,
+                                                      const Registers_ppc &) {
+  return (regNum == UNW_PPC_LR);
+}
+
+template <typename A, typename R>
+typename A::pint_t DwarfInstructions<A, R>::getCFA(
+    A &addressSpace, const PrologInfo &prolog,
+    const Registers_ppc &registers) {
+  if (prolog.cfaRegister != 0)
+    return registers.getRegister(prolog.cfaRegister) + prolog.cfaRegisterOffset;
+  else if (prolog.cfaExpression != 0)
+    return evaluateExpression((pint_t)prolog.cfaExpression, addressSpace,
+                                                                  registers, 0);
+  else
+    _LIBUNWIND_ABORT("getCFA(): unknown location for ppc cfa");
+}
+
+
+
+//
+// arm64 specific functions
+//
+template <typename A, typename R>
+bool DwarfInstructions<A, R>::isReturnAddressRegister(int regNum,
+                                                      const Registers_arm64 &) {
+  return (regNum == UNW_ARM64_LR);
+}
+
+template <typename A, typename R>
+int DwarfInstructions<A, R>::lastRestoreReg(const Registers_arm64 &) {
+  static_assert((int)CFI_Parser<A>::kMaxRegisterNumber
+              > (int)UNW_ARM64_D31, "register number out of range");
+  return UNW_ARM64_D31;
+}
+
+template <typename A, typename R>
+typename A::pint_t DwarfInstructions<A, R>::getCFA(A&, const PrologInfo &prolog,
+                                             const Registers_arm64 &registers) {
+  if (prolog.cfaRegister != 0)
+    return registers.getRegister(prolog.cfaRegister) + prolog.cfaRegisterOffset;
+  else
+    _LIBUNWIND_ABORT("getCFA(): unsupported location for arm64 cfa");
+}
+
+
+} // namespace libunwind
+
+#endif // __DWARF_INSTRUCTIONS_HPP__