Update to current libcxxabi for new exception code.

25 files changed, 12080 insertions, 9785 deletions

diff --git a/system/lib/libcxxabi/src/Unwind/AddressSpace.hpp b/system/lib/libcxxabi/src/Unwind/AddressSpace.hpp
new file mode 100644
index 00000000..67b0973d
--- /dev/null
+++ b/system/lib/libcxxabi/src/Unwind/AddressSpace.hpp
@@ -0,0 +1,430 @@
+//===------------------------- AddressSpace.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.
+//
+//
+// Abstracts accessing local vs remote address spaces.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __ADDRESSSPACE_HPP__
+#define __ADDRESSSPACE_HPP__
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <dlfcn.h>
+
+#if __APPLE__
+#include <mach-o/getsect.h>
+namespace libunwind {
+   bool checkKeyMgrRegisteredFDEs(uintptr_t targetAddr, void *&fde);
+}
+#endif
+
+#include "libunwind.h"
+#include "config.h"
+#include "dwarf2.h"
+#include "Registers.hpp"
+
+namespace libunwind {
+
+/// Used by findUnwindSections() to return info about needed sections.
+struct UnwindInfoSections {
+  uintptr_t        dso_base;
+#if _LIBUNWIND_SUPPORT_DWARF_UNWIND
+  uintptr_t       dwarf_section;
+  uintptr_t       dwarf_section_length;
+#endif
+#if _LIBUNWIND_SUPPORT_DWARF_INDEX
+  uintptr_t       dwarf_index_section;
+  uintptr_t       dwarf_index_section_length;
+#endif
+#if _LIBUNWIND_SUPPORT_COMPACT_UNWIND
+  uintptr_t       compact_unwind_section;
+  uintptr_t       compact_unwind_section_length;
+#endif
+};
+
+
+/// LocalAddressSpace is used as a template parameter to UnwindCursor when
+/// unwinding a thread in the same process.  The wrappers compile away,
+/// making local unwinds fast.
+class __attribute__((visibility("hidden"))) LocalAddressSpace {
+public:
+#if __LP64__
+  typedef uint64_t pint_t;
+  typedef int64_t  sint_t;
+#else
+  typedef uint32_t pint_t;
+  typedef int32_t  sint_t;
+#endif
+  uint8_t         get8(pint_t addr)      { return *((uint8_t *)addr); }
+  uint16_t        get16(pint_t addr)     { return *((uint16_t *)addr); }
+  uint32_t        get32(pint_t addr)     { return *((uint32_t *)addr); }
+  uint64_t        get64(pint_t addr)     { return *((uint64_t *)addr); }
+  double          getDouble(pint_t addr) { return *((double *)addr); }
+  v128            getVector(pint_t addr) { return *((v128 *)addr); }
+  uintptr_t       getP(pint_t addr);
+  static uint64_t getULEB128(pint_t &addr, pint_t end);
+  static int64_t  getSLEB128(pint_t &addr, pint_t end);
+
+  pint_t getEncodedP(pint_t &addr, pint_t end, uint8_t encoding);
+  bool findFunctionName(pint_t addr, char *buf, size_t bufLen,
+                        unw_word_t *offset);
+  bool findUnwindSections(pint_t targetAddr, UnwindInfoSections &info);
+  bool findOtherFDE(pint_t targetAddr, pint_t &fde);
+
+  static LocalAddressSpace sThisAddressSpace;
+};
+
+
+inline uintptr_t LocalAddressSpace::getP(pint_t addr) {
+#if __LP64__
+  return get64(addr);
+#else
+  return get32(addr);
+#endif
+}
+
+/// Read a ULEB128 into a 64-bit word.
+inline uint64_t LocalAddressSpace::getULEB128(pint_t &addr, pint_t end) {
+  const uint8_t *p = (uint8_t *)addr;
+  const uint8_t *pend = (uint8_t *)end;
+  uint64_t result = 0;
+  int bit = 0;
+  do {
+    uint64_t b;
+
+    if (p == pend)
+      _LIBUNWIND_ABORT("truncated uleb128 expression");
+
+    b = *p & 0x7f;
+
+    if (bit >= 64 || b << bit >> bit != b) {
+      _LIBUNWIND_ABORT("malformed uleb128 expression");
+    } else {
+      result |= b << bit;
+      bit += 7;
+    }
+  } while (*p++ >= 0x80);
+  addr = (pint_t) p;
+  return result;
+}
+
+/// Read a SLEB128 into a 64-bit word.
+inline int64_t LocalAddressSpace::getSLEB128(pint_t &addr, pint_t end) {
+  const uint8_t *p = (uint8_t *)addr;
+  const uint8_t *pend = (uint8_t *)end;
+  int64_t result = 0;
+  int bit = 0;
+  uint8_t byte;
+  do {
+    if (p == pend)
+      _LIBUNWIND_ABORT("truncated sleb128 expression");
+    byte = *p++;
+    result |= ((byte & 0x7f) << bit);
+    bit += 7;
+  } while (byte & 0x80);
+  // sign extend negative numbers
+  if ((byte & 0x40) != 0)
+    result |= (-1LL) << bit;
+  addr = (pint_t) p;
+  return result;
+}
+
+inline LocalAddressSpace::pint_t LocalAddressSpace::getEncodedP(pint_t &addr,
+                                                         pint_t end,
+                                                         uint8_t encoding) {
+  pint_t startAddr = addr;
+  const uint8_t *p = (uint8_t *)addr;
+  pint_t result;
+
+  // first get value
+  switch (encoding & 0x0F) {
+  case DW_EH_PE_ptr:
+    result = getP(addr);
+    p += sizeof(pint_t);
+    addr = (pint_t) p;
+    break;
+  case DW_EH_PE_uleb128:
+    result = (pint_t)getULEB128(addr, end);
+    break;
+  case DW_EH_PE_udata2:
+    result = get16(addr);
+    p += 2;
+    addr = (pint_t) p;
+    break;
+  case DW_EH_PE_udata4:
+    result = get32(addr);
+    p += 4;
+    addr = (pint_t) p;
+    break;
+  case DW_EH_PE_udata8:
+    result = (pint_t)get64(addr);
+    p += 8;
+    addr = (pint_t) p;
+    break;
+  case DW_EH_PE_sleb128:
+    result = (pint_t)getSLEB128(addr, end);
+    break;
+  case DW_EH_PE_sdata2:
+    result = (uint16_t)get16(addr);
+    p += 2;
+    addr = (pint_t) p;
+    break;
+  case DW_EH_PE_sdata4:
+    result = (uint32_t)get32(addr);
+    p += 4;
+    addr = (pint_t) p;
+    break;
+  case DW_EH_PE_sdata8:
+    result = (pint_t)get64(addr);
+    p += 8;
+    addr = (pint_t) p;
+    break;
+  default:
+    _LIBUNWIND_ABORT("unknown pointer encoding");
+  }
+
+  // then add relative offset
+  switch (encoding & 0x70) {
+  case DW_EH_PE_absptr:
+    // do nothing
+    break;
+  case DW_EH_PE_pcrel:
+    result += startAddr;
+    break;
+  case DW_EH_PE_textrel:
+    _LIBUNWIND_ABORT("DW_EH_PE_textrel pointer encoding not supported");
+    break;
+  case DW_EH_PE_datarel:
+    _LIBUNWIND_ABORT("DW_EH_PE_datarel pointer encoding not supported");
+    break;
+  case DW_EH_PE_funcrel:
+    _LIBUNWIND_ABORT("DW_EH_PE_funcrel pointer encoding not supported");
+    break;
+  case DW_EH_PE_aligned:
+    _LIBUNWIND_ABORT("DW_EH_PE_aligned pointer encoding not supported");
+    break;
+  default:
+    _LIBUNWIND_ABORT("unknown pointer encoding");
+    break;
+  }
+
+  if (encoding & DW_EH_PE_indirect)
+    result = getP(result);
+
+  return result;
+}
+
+#if __APPLE__ 
+  struct dyld_unwind_sections
+  {
+    const struct mach_header*   mh;
+    const void*                 dwarf_section;
+    uintptr_t                   dwarf_section_length;
+    const void*                 compact_unwind_section;
+    uintptr_t                   compact_unwind_section_length;
+  };
+  #if defined(__MAC_OS_X_VERSION_MIN_REQUIRED) \
+                                  && (__MAC_OS_X_VERSION_MIN_REQUIRED >= 1070)
+    // In 10.7.0 or later, libSystem.dylib implements this function.
+    extern "C" bool _dyld_find_unwind_sections(void *, dyld_unwind_sections *);
+  #else
+    // In 10.6.x and earlier, we need to implement this functionality.
+    static inline bool _dyld_find_unwind_sections(void* addr, 
+                                                    dyld_unwind_sections* info) {
+      // Find mach-o image containing address.
+      Dl_info dlinfo;
+      if (!dladdr(addr, &dlinfo))
+        return false;
+      const mach_header *mh = (const mach_header *)dlinfo.dli_saddr;
+      
+      // Find dwarf unwind section in that image.
+      unsigned long size;
+      const uint8_t *p = getsectiondata(mh, "__TEXT", "__eh_frame", &size);
+      if (!p)
+        return false;
+      
+      // Fill in return struct.
+      info->mh = mh;
+      info->dwarf_section = p;
+      info->dwarf_section_length = size;
+      info->compact_unwind_section = 0;
+      info->compact_unwind_section_length = 0;
+     
+      return true;
+    }
+  #endif
+#endif
+
+inline bool LocalAddressSpace::findUnwindSections(pint_t targetAddr,
+                                                  UnwindInfoSections &info) {
+#if __APPLE__
+  dyld_unwind_sections dyldInfo;
+  if (_dyld_find_unwind_sections((void *)targetAddr, &dyldInfo)) {
+    info.dso_base                      = (uintptr_t)dyldInfo.mh;
+ #if _LIBUNWIND_SUPPORT_DWARF_UNWIND
+    info.dwarf_section                 = (uintptr_t)dyldInfo.dwarf_section;
+    info.dwarf_section_length          = dyldInfo.dwarf_section_length;
+ #endif
+    info.compact_unwind_section        = (uintptr_t)dyldInfo.compact_unwind_section;
+    info.compact_unwind_section_length = dyldInfo.compact_unwind_section_length;
+    return true;
+  }
+#else
+  // TO DO
+
+#endif
+
+  return false;
+}
+
+
+inline bool LocalAddressSpace::findOtherFDE(pint_t targetAddr, pint_t &fde) {
+#if __APPLE__
+  return checkKeyMgrRegisteredFDEs(targetAddr, *((void**)&fde));
+#else
+  // TO DO: if OS has way to dynamically register FDEs, check that.
+  return false;
+#endif
+}
+
+inline bool LocalAddressSpace::findFunctionName(pint_t addr, char *buf,
+                                                size_t bufLen,
+                                                unw_word_t *offset) {
+  dl_info dyldInfo;
+  if (dladdr((void *)addr, &dyldInfo)) {
+    if (dyldInfo.dli_sname != NULL) {
+      strlcpy(buf, dyldInfo.dli_sname, bufLen);
+      *offset = (addr - (pint_t) dyldInfo.dli_saddr);
+      return true;
+    }
+  }
+  return false;
+}
+
+
+
+#if UNW_REMOTE
+
+/// OtherAddressSpace is used as a template parameter to UnwindCursor when
+/// unwinding a thread in the another process.  The other process can be a
+/// different endianness and a different pointer size which is handled by
+/// the P template parameter.
+template <typename P>
+class OtherAddressSpace {
+public:
+  OtherAddressSpace(task_t task) : fTask(task) {}
+
+  typedef typename P::uint_t pint_t;
+
+  uint8_t   get8(pint_t addr);
+  uint16_t  get16(pint_t addr);
+  uint32_t  get32(pint_t addr);
+  uint64_t  get64(pint_t addr);
+  pint_t    getP(pint_t addr);
+  uint64_t  getULEB128(pint_t &addr, pint_t end);
+  int64_t   getSLEB128(pint_t &addr, pint_t end);
+  pint_t    getEncodedP(pint_t &addr, pint_t end, uint8_t encoding);
+  bool      findFunctionName(pint_t addr, char *buf, size_t bufLen,
+                        unw_word_t *offset);
+  bool      findUnwindSections(pint_t targetAddr, UnwindInfoSections &info);
+  bool      findOtherFDE(pint_t targetAddr, pint_t &fde);
+private:
+  void *localCopy(pint_t addr);
+
+  task_t fTask;
+};
+
+template <typename P> uint8_t OtherAddressSpace<P>::get8(pint_t addr) {
+  return *((uint8_t *)localCopy(addr));
+}
+
+template <typename P> uint16_t OtherAddressSpace<P>::get16(pint_t addr) {
+  return P::E::get16(*(uint16_t *)localCopy(addr));
+}
+
+template <typename P> uint32_t OtherAddressSpace<P>::get32(pint_t addr) {
+  return P::E::get32(*(uint32_t *)localCopy(addr));
+}
+
+template <typename P> uint64_t OtherAddressSpace<P>::get64(pint_t addr) {
+  return P::E::get64(*(uint64_t *)localCopy(addr));
+}
+
+template <typename P>
+typename P::uint_t OtherAddressSpace<P>::getP(pint_t addr) {
+  return P::getP(*(uint64_t *)localCopy(addr));
+}
+
+template <typename P>
+uint64_t OtherAddressSpace<P>::getULEB128(pint_t &addr, pint_t end) {
+  uintptr_t size = (end - addr);
+  LocalAddressSpace::pint_t laddr = (LocalAddressSpace::pint_t) localCopy(addr);
+  LocalAddressSpace::pint_t sladdr = laddr;
+  uint64_t result = LocalAddressSpace::getULEB128(laddr, laddr + size);
+  addr += (laddr - sladdr);
+  return result;
+}
+
+template <typename P>
+int64_t OtherAddressSpace<P>::getSLEB128(pint_t &addr, pint_t end) {
+  uintptr_t size = (end - addr);
+  LocalAddressSpace::pint_t laddr = (LocalAddressSpace::pint_t) localCopy(addr);
+  LocalAddressSpace::pint_t sladdr = laddr;
+  uint64_t result = LocalAddressSpace::getSLEB128(laddr, laddr + size);
+  addr += (laddr - sladdr);
+  return result;
+}
+
+template <typename P> void *OtherAddressSpace<P>::localCopy(pint_t addr) {
+  // FIX ME
+}
+
+template <typename P>
+bool OtherAddressSpace<P>::findFunctionName(pint_t addr, char *buf,
+                                            size_t bufLen, unw_word_t *offset) {
+  // FIX ME
+}
+
+/// unw_addr_space is the base class that abstract unw_addr_space_t type in
+/// libunwind.h points to.
+struct unw_addr_space {
+  cpu_type_t cpuType;
+  task_t taskPort;
+};
+
+/// unw_addr_space_i386 is the concrete instance that a unw_addr_space_t points
+/// to when examining
+/// a 32-bit intel process.
+struct unw_addr_space_i386 : public unw_addr_space {
+  unw_addr_space_i386(task_t task) : oas(task) {}
+  OtherAddressSpace<Pointer32<LittleEndian> > oas;
+};
+
+/// unw_addr_space_x86_64 is the concrete instance that a unw_addr_space_t
+/// points to when examining
+/// a 64-bit intel process.
+struct unw_addr_space_x86_64 : public unw_addr_space {
+  unw_addr_space_x86_64(task_t task) : oas(task) {}
+  OtherAddressSpace<Pointer64<LittleEndian> > oas;
+};
+
+/// unw_addr_space_ppc is the concrete instance that a unw_addr_space_t points
+/// to when examining
+/// a 32-bit PowerPC process.
+struct unw_addr_space_ppc : public unw_addr_space {
+  unw_addr_space_ppc(task_t task) : oas(task) {}
+  OtherAddressSpace<Pointer32<BigEndian> > oas;
+};
+
+#endif // UNW_REMOTE
+
+} // namespace libunwind
+
+#endif // __ADDRESSSPACE_HPP__
diff --git a/system/lib/libcxxabi/src/Unwind/CompactUnwinder.hpp b/system/lib/libcxxabi/src/Unwind/CompactUnwinder.hpp
new file mode 100644
index 00000000..0dc187f1
--- /dev/null
+++ b/system/lib/libcxxabi/src/Unwind/CompactUnwinder.hpp
@@ -0,0 +1,693 @@
+//===-------------------------- CompactUnwinder.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.
+//
+//
+//  Does runtime stack unwinding using compact unwind encodings.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __COMPACT_UNWINDER_HPP__
+#define __COMPACT_UNWINDER_HPP__
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#include <libunwind.h>
+#include <mach-o/compact_unwind_encoding.h>
+
+#include "AddressSpace.hpp"
+#include "Registers.hpp"
+
+#define EXTRACT_BITS(value, mask)                                              \
+  ((value >> __builtin_ctz(mask)) & (((1 << __builtin_popcount(mask))) - 1))
+
+namespace libunwind {
+
+/// CompactUnwinder_x86 uses a compact unwind info to virtually "step" (aka
+/// unwind) by modifying a Registers_x86 register set
+template <typename A>
+class CompactUnwinder_x86 {
+public:
+
+  static int stepWithCompactEncoding(compact_unwind_encoding_t info,
+                                     uint32_t functionStart, A &addressSpace,
+                                     Registers_x86 &registers);
+
+private:
+  typename A::pint_t pint_t;
+
+  static void frameUnwind(A &addressSpace, Registers_x86 &registers);
+  static void framelessUnwind(A &addressSpace,
+                              typename A::pint_t returnAddressLocation,
+                              Registers_x86 &registers);
+  static int
+      stepWithCompactEncodingEBPFrame(compact_unwind_encoding_t compactEncoding,
+                                      uint32_t functionStart, A &addressSpace,
+                                      Registers_x86 &registers);
+  static int stepWithCompactEncodingFrameless(
+      compact_unwind_encoding_t compactEncoding, uint32_t functionStart,
+      A &addressSpace, Registers_x86 &registers, bool indirectStackSize);
+};
+
+template <typename A>
+int CompactUnwinder_x86<A>::stepWithCompactEncoding(
+    compact_unwind_encoding_t compactEncoding, uint32_t functionStart,
+    A &addressSpace, Registers_x86 &registers) {
+  switch (compactEncoding & UNWIND_X86_MODE_MASK) {
+  case UNWIND_X86_MODE_EBP_FRAME:
+    return stepWithCompactEncodingEBPFrame(compactEncoding, functionStart,
+                                           addressSpace, registers);
+  case UNWIND_X86_MODE_STACK_IMMD:
+    return stepWithCompactEncodingFrameless(compactEncoding, functionStart,
+                                            addressSpace, registers, false);
+  case UNWIND_X86_MODE_STACK_IND:
+    return stepWithCompactEncodingFrameless(compactEncoding, functionStart,
+                                            addressSpace, registers, true);
+  }
+  _LIBUNWIND_ABORT("invalid compact unwind encoding");
+}
+
+template <typename A>
+int CompactUnwinder_x86<A>::stepWithCompactEncodingEBPFrame(
+    compact_unwind_encoding_t compactEncoding, uint32_t functionStart,
+    A &addressSpace, Registers_x86 &registers) {
+  uint32_t savedRegistersOffset =
+      EXTRACT_BITS(compactEncoding, UNWIND_X86_EBP_FRAME_OFFSET);
+  uint32_t savedRegistersLocations =
+      EXTRACT_BITS(compactEncoding, UNWIND_X86_EBP_FRAME_REGISTERS);
+
+  uint32_t savedRegisters = registers.getEBP() - 4 * savedRegistersOffset;
+  for (int i = 0; i < 5; ++i) {
+    switch (savedRegistersLocations & 0x7) {
+    case UNWIND_X86_REG_NONE:
+      // no register saved in this slot
+      break;
+    case UNWIND_X86_REG_EBX:
+      registers.setEBX(addressSpace.get32(savedRegisters));
+      break;
+    case UNWIND_X86_REG_ECX:
+      registers.setECX(addressSpace.get32(savedRegisters));
+      break;
+    case UNWIND_X86_REG_EDX:
+      registers.setEDX(addressSpace.get32(savedRegisters));
+      break;
+    case UNWIND_X86_REG_EDI:
+      registers.setEDI(addressSpace.get32(savedRegisters));
+      break;
+    case UNWIND_X86_REG_ESI:
+      registers.setESI(addressSpace.get32(savedRegisters));
+      break;
+    default:
+      (void)functionStart;
+      _LIBUNWIND_DEBUG_LOG("bad register for EBP frame, encoding=%08X for  "
+                           "function starting at 0x%X\n",
+                            compactEncoding, functionStart);
+      _LIBUNWIND_ABORT("invalid compact unwind encoding");
+    }
+    savedRegisters += 4;
+    savedRegistersLocations = (savedRegistersLocations >> 3);
+  }
+  frameUnwind(addressSpace, registers);
+  return UNW_STEP_SUCCESS;
+}
+
+template <typename A>
+int CompactUnwinder_x86<A>::stepWithCompactEncodingFrameless(
+    compact_unwind_encoding_t encoding, uint32_t functionStart,
+    A &addressSpace, Registers_x86 &registers, bool indirectStackSize) {
+  uint32_t stackSizeEncoded =
+      EXTRACT_BITS(encoding, UNWIND_X86_FRAMELESS_STACK_SIZE);
+  uint32_t stackAdjust =
+      EXTRACT_BITS(encoding, UNWIND_X86_FRAMELESS_STACK_ADJUST);
+  uint32_t regCount =
+      EXTRACT_BITS(encoding, UNWIND_X86_FRAMELESS_STACK_REG_COUNT);
+  uint32_t permutation =
+      EXTRACT_BITS(encoding, UNWIND_X86_FRAMELESS_STACK_REG_PERMUTATION);
+  uint32_t stackSize = stackSizeEncoded * 4;
+  if (indirectStackSize) {
+    // stack size is encoded in subl $xxx,%esp instruction
+    uint32_t subl = addressSpace.get32(functionStart + stackSizeEncoded);
+    stackSize = subl + 4 * stackAdjust;
+  }
+  // decompress permutation
+  uint32_t permunreg[6];
+  switch (regCount) {
+  case 6:
+    permunreg[0] = permutation / 120;
+    permutation -= (permunreg[0] * 120);
+    permunreg[1] = permutation / 24;
+    permutation -= (permunreg[1] * 24);
+    permunreg[2] = permutation / 6;
+    permutation -= (permunreg[2] * 6);
+    permunreg[3] = permutation / 2;
+    permutation -= (permunreg[3] * 2);
+    permunreg[4] = permutation;
+    permunreg[5] = 0;
+    break;
+  case 5:
+    permunreg[0] = permutation / 120;
+    permutation -= (permunreg[0] * 120);
+    permunreg[1] = permutation / 24;
+    permutation -= (permunreg[1] * 24);
+    permunreg[2] = permutation / 6;
+    permutation -= (permunreg[2] * 6);
+    permunreg[3] = permutation / 2;
+    permutation -= (permunreg[3] * 2);
+    permunreg[4] = permutation;
+    break;
+  case 4:
+    permunreg[0] = permutation / 60;
+    permutation -= (permunreg[0] * 60);
+    permunreg[1] = permutation / 12;
+    permutation -= (permunreg[1] * 12);
+    permunreg[2] = permutation / 3;
+    permutation -= (permunreg[2] * 3);
+    permunreg[3] = permutation;
+    break;
+  case 3:
+    permunreg[0] = permutation / 20;
+    permutation -= (permunreg[0] * 20);
+    permunreg[1] = permutation / 4;
+    permutation -= (permunreg[1] * 4);
+    permunreg[2] = permutation;
+    break;
+  case 2:
+    permunreg[0] = permutation / 5;
+    permutation -= (permunreg[0] * 5);
+    permunreg[1] = permutation;
+    break;
+  case 1:
+    permunreg[0] = permutation;
+    break;
+  }
+  // re-number registers back to standard numbers
+  int registersSaved[6];
+  bool used[7] = { false, false, false, false, false, false, false };
+  for (uint32_t i = 0; i < regCount; ++i) {
+    uint32_t renum = 0;
+    for (int u = 1; u < 7; ++u) {
+      if (!used[u]) {
+        if (renum == permunreg[i]) {
+          registersSaved[i] = u;
+          used[u] = true;
+          break;
+        }
+        ++renum;
+      }
+    }
+  }
+  uint32_t savedRegisters = registers.getSP() + stackSize - 4 - 4 * regCount;
+  for (uint32_t i = 0; i < regCount; ++i) {
+    switch (registersSaved[i]) {
+    case UNWIND_X86_REG_EBX:
+      registers.setEBX(addressSpace.get32(savedRegisters));
+      break;
+    case UNWIND_X86_REG_ECX:
+      registers.setECX(addressSpace.get32(savedRegisters));
+      break;
+    case UNWIND_X86_REG_EDX:
+      registers.setEDX(addressSpace.get32(savedRegisters));
+      break;
+    case UNWIND_X86_REG_EDI:
+      registers.setEDI(addressSpace.get32(savedRegisters));
+      break;
+    case UNWIND_X86_REG_ESI:
+      registers.setESI(addressSpace.get32(savedRegisters));
+      break;
+    case UNWIND_X86_REG_EBP:
+      registers.setEBP(addressSpace.get32(savedRegisters));
+      break;
+    default:
+      _LIBUNWIND_DEBUG_LOG("bad register for frameless, encoding=%08X for "
+                           "function starting at 0x%X\n",
+                           encoding, functionStart);
+      _LIBUNWIND_ABORT("invalid compact unwind encoding");
+    }
+    savedRegisters += 4;
+  }
+  framelessUnwind(addressSpace, savedRegisters, registers);
+  return UNW_STEP_SUCCESS;
+}
+
+
+template <typename A>
+void CompactUnwinder_x86<A>::frameUnwind(A &addressSpace,
+                                         Registers_x86 &registers) {
+  typename A::pint_t bp = registers.getEBP();
+  // ebp points to old ebp
+  registers.setEBP(addressSpace.get32(bp));
+  // old esp is ebp less saved ebp and return address
+  registers.setSP((uint32_t)bp + 8);
+  // pop return address into eip
+  registers.setIP(addressSpace.get32(bp + 4));
+}
+
+template <typename A>
+void CompactUnwinder_x86<A>::framelessUnwind(
+    A &addressSpace, typename A::pint_t returnAddressLocation,
+    Registers_x86 &registers) {
+  // return address is on stack after last saved register
+  registers.setIP(addressSpace.get32(returnAddressLocation));
+  // old esp is before return address
+  registers.setSP((uint32_t)returnAddressLocation + 4);
+}
+
+
+/// CompactUnwinder_x86_64 uses a compact unwind info to virtually "step" (aka
+/// unwind) by modifying a Registers_x86_64 register set
+template <typename A>
+class CompactUnwinder_x86_64 {
+public:
+
+  static int stepWithCompactEncoding(compact_unwind_encoding_t compactEncoding,
+                                     uint64_t functionStart, A &addressSpace,
+                                     Registers_x86_64 &registers);
+
+private:
+  typename A::pint_t pint_t;
+
+  static void frameUnwind(A &addressSpace, Registers_x86_64 &registers);
+  static void framelessUnwind(A &addressSpace, uint64_t returnAddressLocation,
+                              Registers_x86_64 &registers);
+  static int
+      stepWithCompactEncodingRBPFrame(compact_unwind_encoding_t compactEncoding,
+                                      uint64_t functionStart, A &addressSpace,
+                                      Registers_x86_64 &registers);
+  static int stepWithCompactEncodingFrameless(
+      compact_unwind_encoding_t compactEncoding, uint64_t functionStart,
+      A &addressSpace, Registers_x86_64 &registers, bool indirectStackSize);
+};
+
+template <typename A>
+int CompactUnwinder_x86_64<A>::stepWithCompactEncoding(
+    compact_unwind_encoding_t compactEncoding, uint64_t functionStart,
+    A &addressSpace, Registers_x86_64 &registers) {
+  switch (compactEncoding & UNWIND_X86_64_MODE_MASK) {
+  case UNWIND_X86_64_MODE_RBP_FRAME:
+    return stepWithCompactEncodingRBPFrame(compactEncoding, functionStart,
+                                           addressSpace, registers);
+  case UNWIND_X86_64_MODE_STACK_IMMD:
+    return stepWithCompactEncodingFrameless(compactEncoding, functionStart,
+                                            addressSpace, registers, false);
+  case UNWIND_X86_64_MODE_STACK_IND:
+    return stepWithCompactEncodingFrameless(compactEncoding, functionStart,
+                                            addressSpace, registers, true);
+  }
+  _LIBUNWIND_ABORT("invalid compact unwind encoding");
+}
+
+template <typename A>
+int CompactUnwinder_x86_64<A>::stepWithCompactEncodingRBPFrame(
+    compact_unwind_encoding_t compactEncoding, uint64_t functionStart,
+    A &addressSpace, Registers_x86_64 &registers) {
+  uint32_t savedRegistersOffset =
+      EXTRACT_BITS(compactEncoding, UNWIND_X86_64_RBP_FRAME_OFFSET);
+  uint32_t savedRegistersLocations =
+      EXTRACT_BITS(compactEncoding, UNWIND_X86_64_RBP_FRAME_REGISTERS);
+
+  uint64_t savedRegisters = registers.getRBP() - 8 * savedRegistersOffset;
+  for (int i = 0; i < 5; ++i) {
+    switch (savedRegistersLocations & 0x7) {
+    case UNWIND_X86_64_REG_NONE:
+      // no register saved in this slot
+      break;
+    case UNWIND_X86_64_REG_RBX:
+      registers.setRBX(addressSpace.get64(savedRegisters));
+      break;
+    case UNWIND_X86_64_REG_R12:
+      registers.setR12(addressSpace.get64(savedRegisters));
+      break;
+    case UNWIND_X86_64_REG_R13:
+      registers.setR13(addressSpace.get64(savedRegisters));
+      break;
+    case UNWIND_X86_64_REG_R14:
+      registers.setR14(addressSpace.get64(savedRegisters));
+      break;
+    case UNWIND_X86_64_REG_R15:
+      registers.setR15(addressSpace.get64(savedRegisters));
+      break;
+    default:
+      (void)functionStart;
+      _LIBUNWIND_DEBUG_LOG("bad register for RBP frame, encoding=%08X for "
+                           "function starting at 0x%llX\n",
+                            compactEncoding, functionStart);
+      _LIBUNWIND_ABORT("invalid compact unwind encoding");
+    }
+    savedRegisters += 8;
+    savedRegistersLocations = (savedRegistersLocations >> 3);
+  }
+  frameUnwind(addressSpace, registers);
+  return UNW_STEP_SUCCESS;
+}
+
+template <typename A>
+int CompactUnwinder_x86_64<A>::stepWithCompactEncodingFrameless(
+    compact_unwind_encoding_t encoding, uint64_t functionStart, A &addressSpace,
+    Registers_x86_64 &registers, bool indirectStackSize) {
+  uint32_t stackSizeEncoded =
+      EXTRACT_BITS(encoding, UNWIND_X86_64_FRAMELESS_STACK_SIZE);
+  uint32_t stackAdjust =
+      EXTRACT_BITS(encoding, UNWIND_X86_64_FRAMELESS_STACK_ADJUST);
+  uint32_t regCount =
+      EXTRACT_BITS(encoding, UNWIND_X86_64_FRAMELESS_STACK_REG_COUNT);
+  uint32_t permutation =
+      EXTRACT_BITS(encoding, UNWIND_X86_64_FRAMELESS_STACK_REG_PERMUTATION);
+  uint32_t stackSize = stackSizeEncoded * 8;
+  if (indirectStackSize) {
+    // stack size is encoded in subl $xxx,%esp instruction
+    uint32_t subl = addressSpace.get32(functionStart + stackSizeEncoded);
+    stackSize = subl + 8 * stackAdjust;
+  }
+  // decompress permutation
+  uint32_t permunreg[6];
+  switch (regCount) {
+  case 6:
+    permunreg[0] = permutation / 120;
+    permutation -= (permunreg[0] * 120);
+    permunreg[1] = permutation / 24;
+    permutation -= (permunreg[1] * 24);
+    permunreg[2] = permutation / 6;
+    permutation -= (permunreg[2] * 6);
+    permunreg[3] = permutation / 2;
+    permutation -= (permunreg[3] * 2);
+    permunreg[4] = permutation;
+    permunreg[5] = 0;
+    break;
+  case 5:
+    permunreg[0] = permutation / 120;
+    permutation -= (permunreg[0] * 120);
+    permunreg[1] = permutation / 24;
+    permutation -= (permunreg[1] * 24);
+    permunreg[2] = permutation / 6;
+    permutation -= (permunreg[2] * 6);
+    permunreg[3] = permutation / 2;
+    permutation -= (permunreg[3] * 2);
+    permunreg[4] = permutation;
+    break;
+  case 4:
+    permunreg[0] = permutation / 60;
+    permutation -= (permunreg[0] * 60);
+    permunreg[1] = permutation / 12;
+    permutation -= (permunreg[1] * 12);
+    permunreg[2] = permutation / 3;
+    permut