The Tor Browser: toolkit/crashreporter/breakpad-patches/12-bug863475.patch@6474c204b198 (annotated)

toolkit/crashreporter/breakpad-patches/12-bug863475.patch@6474c204b198 (annotated)

toolkit/crashreporter/breakpad-patches/12-bug863475.patch

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 # HG changeset patch
 # User Julian Seward <jseward@acm.org>
 # Date 1371190160 -7200
 #      Fri Jun 14 08:09:20 2013 +0200
 # Node ID e74de3db7dd27ffda8f4772f892cfb52c5c35649
 # Parent  4dcd4220c31068e116d88a58e5b396fbb01719dd
 Bug 863475 - integrate ARM EXIDX unwind parsing into Breakpad.  r=glandium,ted
 diff --git a/Makefile.am b/Makefile.am
 --- a/Makefile.am
 +++ b/Makefile.am
@@ -428,16 +428,18 @@ src_tools_linux_dump_syms_dump_syms_SOUR
  	src/common/dwarf_line_to_module.cc \
  	src/common/language.cc \
  	src/common/module.cc \
  	src/common/stabs_reader.cc \
  	src/common/stabs_to_module.cc \
  	src/common/dwarf/bytereader.cc \
  	src/common/dwarf/dwarf2diehandler.cc \
  	src/common/dwarf/dwarf2reader.cc \
 +        src/common/arm_ex_reader.cc \
 +        src/common/arm_ex_to_module.cc \
  	src/common/linux/dump_symbols.cc \
  	src/common/linux/elf_symbols_to_module.cc \
  	src/common/linux/elfutils.cc \
  	src/common/linux/file_id.cc \
  	src/common/linux/linux_libc_support.cc \
  	src/common/linux/memory_mapped_file.cc \
  	src/common/linux/safe_readlink.cc \
  	src/tools/linux/dump_syms/dump_syms.cc
@@ -1010,16 +1012,20 @@ EXTRA_DIST = \
  	src/client/windows/handler/exception_handler.vcproj \
  	src/client/windows/sender/crash_report_sender.cc \
  	src/client/windows/sender/crash_report_sender.h \
  	src/client/windows/sender/crash_report_sender.vcproj \
  	src/common/convert_UTF.c \
  	src/common/convert_UTF.h \
  	src/common/linux/dump_symbols.cc \
  	src/common/linux/dump_symbols.h \
 +        src/common/arm_ex_reader.cc \
 +        src/common/arm_ex_reader.h \
 +        src/common/arm_ex_to_module.cc \
 +        src/common/arm_ex_to_module.h \
  	src/common/linux/elf_symbols_to_module.cc \
  	src/common/linux/elf_symbols_to_module.h \
  	src/common/linux/elfutils.cc \
  	src/common/linux/elfutils.h \
  	src/common/linux/file_id.cc \
  	src/common/linux/file_id.h \
  	src/common/linux/guid_creator.cc \
  	src/common/linux/guid_creator.h \
 diff --git a/src/common/arm_ex_reader.cc b/src/common/arm_ex_reader.cc
 new file mode 100644
 --- /dev/null
 +++ b/src/common/arm_ex_reader.cc
@@ -0,0 +1,502 @@
 +
 +/* libunwind - a platform-independent unwind library
 +   Copyright 2011 Linaro Limited
 +
 +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.  */
 +
 +// Copyright (c) 2010 Google Inc.
 +// All rights reserved.
 +//
 +// Redistribution and use in source and binary forms, with or without
 +// modification, are permitted provided that the following conditions are
 +// met:
 +//
 +//     * Redistributions of source code must retain the above copyright
 +// notice, this list of conditions and the following disclaimer.
 +//     * Redistributions in binary form must reproduce the above
 +// copyright notice, this list of conditions and the following disclaimer
 +// in the documentation and/or other materials provided with the
 +// distribution.
 +//     * Neither the name of Google Inc. nor the names of its
 +// contributors may be used to endorse or promote products derived from
 +// this software without specific prior written permission.
 +//
 +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 +
 +
 +// Derived from libunwind, with extensive modifications.
 +
 +
 +#include "common/arm_ex_reader.h"
 +#include "common/logging.h"
 +
 +#include <assert.h>
 +
 +// This file, in conjunction with arm_ex_to_module.cc, translates
 +// EXIDX unwind information into the same format that Breakpad uses
 +// for CFI information.  Hence Breakpad's CFI unwinding abilities
 +// also become usable for EXIDX.
 +//
 +// See: "Exception Handling ABI for the ARM Architecture", ARM IHI 0038A
 +// http://infocenter.arm.com/help/topic/com.arm.doc.ihi0038a/IHI0038A_ehabi.pdf
 +
 +// EXIDX data is presented in two parts:
 +//
 +// * an index table.  This contains two words per routine,
 +//   the first of which identifies the routine, and the second
 +//   of which is a reference to the unwind bytecode.  If the
 +//   bytecode is very compact -- 3 bytes or less -- it can be
 +//   stored directly in the second word.
 +//
 +// * an area containing the unwind bytecodes.
 +
 +// General flow is: ExceptionTableInfo::Start iterates over all
 +// of the index table entries (pairs).  For each entry, it:
 +//
 +// * calls ExceptionTableInfo::ExtabEntryExtract to copy the bytecode
 +//   out into an intermediate buffer.
 +
 +// * uses ExceptionTableInfo::ExtabEntryDecode to parse the intermediate
 +//   buffer.  Each bytecode instruction is bundled into a
 +//   arm_ex_to_module::extab_data structure, and handed to ..
 +//
 +// * .. ARMExToModule::ImproveStackFrame, which in turn hands it to
 +//   ARMExToModule::TranslateCmd, and that generates the pseudo-CFI
 +//   records that Breakpad stores.
 +
 +#define ARM_EXIDX_CANT_UNWIND 0x00000001
 +#define ARM_EXIDX_COMPACT     0x80000000
 +#define ARM_EXTBL_OP_FINISH   0xb0
 +#define ARM_EXIDX_TABLE_LIMIT (255*4)
 +
 +namespace arm_ex_reader {
 +
 +using arm_ex_to_module::ARM_EXIDX_CMD_FINISH;
 +using arm_ex_to_module::ARM_EXIDX_CMD_SUB_FROM_VSP;
 +using arm_ex_to_module::ARM_EXIDX_CMD_ADD_TO_VSP;
 +using arm_ex_to_module::ARM_EXIDX_CMD_REG_POP;
 +using arm_ex_to_module::ARM_EXIDX_CMD_REG_TO_SP;
 +using arm_ex_to_module::ARM_EXIDX_CMD_VFP_POP;
 +using arm_ex_to_module::ARM_EXIDX_CMD_WREG_POP;
 +using arm_ex_to_module::ARM_EXIDX_CMD_WCGR_POP;
 +using arm_ex_to_module::ARM_EXIDX_CMD_RESERVED;
 +using arm_ex_to_module::ARM_EXIDX_CMD_REFUSED;
 +using arm_ex_to_module::exidx_entry;
 +using arm_ex_to_module::ARM_EXIDX_VFP_SHIFT_16;
 +using arm_ex_to_module::ARM_EXIDX_VFP_FSTMD;
 +using google_breakpad::MemoryRange;
 +
 +
 +static void* Prel31ToAddr(const void* addr)
 +{
 +  uint32_t offset32 = *reinterpret_cast<const uint32_t*>(addr);
 +  // sign extend offset32[30:0] to 64 bits -- copy bit 30 to positions
 +  // 63:31 inclusive.
 +  uint64_t offset64 = offset32;
 +  if (offset64 & (1ULL << 30))
 +    offset64 |= 0xFFFFFFFF80000000ULL;
 +  else
 +    offset64 &= 0x000000007FFFFFFFULL;
 +  return ((char*)addr) + (uintptr_t)offset64;
 +}
 +
 +
 +// Extract unwind bytecode for the function denoted by |entry| into |buf|,
 +// and return the number of bytes of |buf| written, along with a code
 +// indicating the outcome.
 +
 +ExceptionTableInfo::ExExtractResult
 +ExceptionTableInfo::ExtabEntryExtract(const struct exidx_entry* entry,
 +                                      uint8_t* buf, size_t buf_size,
 +                                      /*OUT*/size_t* buf_used)
 +{
 +  MemoryRange mr_out(buf, buf_size);
 +
 +  *buf_used = 0;
 +
 +# define PUT_BUF_U8(_byte) \
 +  do { if (!mr_out.Covers(*buf_used, 1)) return ExOutBufOverflow; \
 +       buf[(*buf_used)++] = (_byte); } while (0)
 +
 +# define GET_EX_U32(_lval, _addr, _sec_mr) \
 +  do { if (!(_sec_mr).Covers(reinterpret_cast<const uint8_t*>(_addr) \
 +                             - (_sec_mr).data(), 4)) \
 +         return ExInBufOverflow; \
 +       (_lval) = *(reinterpret_cast<const uint32_t*>(_addr)); } while (0)
 +
 +# define GET_EXIDX_U32(_lval, _addr) \
 +            GET_EX_U32(_lval, _addr, mr_exidx_)
 +# define GET_EXTAB_U32(_lval, _addr) \
 +            GET_EX_U32(_lval, _addr, mr_extab_)
 +
 +  uint32_t data;
 +  GET_EXIDX_U32(data, &entry->data);
 +
 +  // A function can be marked CANT_UNWIND if (eg) it is known to be
 +  // at the bottom of the stack.
 +  if (data == ARM_EXIDX_CANT_UNWIND)
 +    return ExCantUnwind;
 +
 +  uint32_t  pers;          // personality number
 +  uint32_t  extra;         // number of extra data words required
 +  uint32_t  extra_allowed; // number of extra data words allowed
 +  uint32_t* extbl_data;    // the handler entry, if not inlined
 +
 +  if (data & ARM_EXIDX_COMPACT) {
 +    // The handler table entry has been inlined into the index table entry.
 +    // In this case it can only be an ARM-defined compact model, since
 +    // bit 31 is 1.  Only personalities 0, 1 and 2 are defined for the
 +    // ARM compact model, but 1 and 2 are "Long format" and may require
 +    // extra data words.  Hence the allowable personalities here are:
 +    //   personality 0, in which case 'extra' has no meaning
 +    //   personality 1, with zero extra words
 +    //   personality 2, with zero extra words
 +    extbl_data = NULL;
 +    pers  = (data >> 24) & 0x0F;
 +    extra = (data >> 16) & 0xFF;
 +    extra_allowed = 0;
 +  }
 +  else {
 +    // The index table entry is a pointer to the handler entry.  Note
 +    // that Prel31ToAddr will read the given address, but we already
 +    // range-checked above.
 +    extbl_data = reinterpret_cast<uint32_t*>(Prel31ToAddr(&entry->data));
 +    GET_EXTAB_U32(data, extbl_data);
 +    if (!(data & ARM_EXIDX_COMPACT)) {
 +      // This denotes a "generic model" handler.  That will involve
 +      // executing arbitary machine code, which is something we
 +      // can't represent here; hence reject it.
 +      return ExCantRepresent;
 +    }
 +    // So we have a compact model representation.  Again, 3 possible
 +    // personalities, but this time up to 255 allowable extra words.
 +    pers  = (data >> 24) & 0x0F;
 +    extra = (data >> 16) & 0xFF;
 +    extra_allowed = 255;
 +    extbl_data++;
 +  }
 +
 +  // Now look at the the handler table entry.  The first word is
 +  // |data| and subsequent words start at |*extbl_data|.  The number
 +  // of extra words to use is |extra|, provided that the personality
 +  // allows extra words.  Even if it does, none may be available --
 +  // extra_allowed is the maximum number of extra words allowed. */
 +  if (pers == 0) {
 +    // "Su16" in the documentation -- 3 unwinding insn bytes
 +    // |extra| has no meaning here; instead that byte is an unwind-info byte
 +    PUT_BUF_U8(data >> 16);
 +    PUT_BUF_U8(data >> 8);
 +    PUT_BUF_U8(data);
 +  }
 +  else if ((pers == 1 || pers == 2) && extra <= extra_allowed) {
 +    // "Lu16" or "Lu32" respectively -- 2 unwinding insn bytes,
 +    // and up to 255 extra words.
 +    PUT_BUF_U8(data >> 8);
 +    PUT_BUF_U8(data);
 +    for (uint32_t j = 0; j < extra; j++) {
 +      GET_EXTAB_U32(data, extbl_data);
 +      extbl_data++;
 +      PUT_BUF_U8(data >> 24);
 +      PUT_BUF_U8(data >> 16);
 +      PUT_BUF_U8(data >> 8);
 +      PUT_BUF_U8(data >> 0);
 +    }
 +  }
 +  else {
 +    // The entry is invalid.
 +    return ExInvalid;
 +  }
 +
 +  // Make sure the entry is terminated with "FINISH"
 +  if (*buf_used > 0 && buf[(*buf_used) - 1] != ARM_EXTBL_OP_FINISH)
 +    PUT_BUF_U8(ARM_EXTBL_OP_FINISH);
 +
 +  return ExSuccess;
 +
 +# undef GET_EXTAB_U32
 +# undef GET_EXIDX_U32
 +# undef GET_U32
 +# undef PUT_BUF_U8
 +}
 +
 +
 +// Take the unwind information extracted by ExtabEntryExtract
 +// and parse it into frame-unwind instructions.  These are as
 +// specified in "Table 4, ARM-defined frame-unwinding instructions"
 +// in the specification document detailed in comments at the top
 +// of this file.
 +//
 +// This reads from |buf[0, +data_size)|.  It checks for overruns of
 +// the input buffer and returns a negative value if that happens, or
 +// for any other failure cases.  It returns zero in case of success.
 +int ExceptionTableInfo::ExtabEntryDecode(const uint8_t* buf, size_t buf_size)
 +{
 +  if (buf == NULL || buf_size == 0)
 +    return -1;
 +
 +  MemoryRange mr_in(buf, buf_size);
 +  const uint8_t* buf_initially = buf;
 +
 +# define GET_BUF_U8(_lval) \
 +  do { if (!mr_in.Covers(buf - buf_initially, 1)) return -1; \
 +       (_lval) = *(buf++); } while (0)
 +
 +  const uint8_t* end = buf + buf_size;
 +
 +  while (buf < end) {
 +    struct arm_ex_to_module::extab_data edata;
 +    memset(&edata, 0, sizeof(edata));
 +
 +    uint8_t op;
 +    GET_BUF_U8(op);
 +    if ((op & 0xc0) == 0x00) {
 +      // vsp = vsp + (xxxxxx << 2) + 4
 +      edata.cmd = ARM_EXIDX_CMD_ADD_TO_VSP;
 +      edata.data = (((int)op & 0x3f) << 2) + 4;
 +    }
 +    else if ((op & 0xc0) == 0x40) {
 +      // vsp = vsp - (xxxxxx << 2) - 4
 +      edata.cmd = ARM_EXIDX_CMD_SUB_FROM_VSP;
 +      edata.data = (((int)op & 0x3f) << 2) + 4;
 +    }
 +    else if ((op & 0xf0) == 0x80) {
 +      uint8_t op2;
 +      GET_BUF_U8(op2);
 +      if (op == 0x80 && op2 == 0x00) {
 +        // Refuse to unwind
 +        edata.cmd = ARM_EXIDX_CMD_REFUSED;
 +      } else {
 +        // Pop up to 12 integer registers under masks {r15-r12},{r11-r4}
 +        edata.cmd = ARM_EXIDX_CMD_REG_POP;
 +        edata.data = ((op & 0xf) << 8) | op2;
 +        edata.data = edata.data << 4;
 +      }
 +    }
 +    else if ((op & 0xf0) == 0x90) {
 +      if (op == 0x9d || op == 0x9f) {
 +        // 9d: Reserved as prefix for ARM register to register moves
 +        // 9f: Reserved as perfix for Intel Wireless MMX reg to reg moves
 +        edata.cmd = ARM_EXIDX_CMD_RESERVED;
 +      } else {
 +        // Set vsp = r[nnnn]
 +        edata.cmd = ARM_EXIDX_CMD_REG_TO_SP;
 +        edata.data = op & 0x0f;
 +      }
 +    }
 +    else if ((op & 0xf0) == 0xa0) {
 +      // Pop r4 to r[4+nnn],          or
 +      // Pop r4 to r[4+nnn] and r14   or
 +      unsigned end = (op & 0x07);
 +      edata.data = (1 << (end + 1)) - 1;
 +      edata.data = edata.data << 4;
 +      if (op & 0x08) edata.data |= 1 << 14;
 +      edata.cmd = ARM_EXIDX_CMD_REG_POP;
 +    }
 +    else if (op == ARM_EXTBL_OP_FINISH) {
 +      // Finish
 +      edata.cmd = ARM_EXIDX_CMD_FINISH;
 +      buf = end;
 +    }
 +    else if (op == 0xb1) {
 +      uint8_t op2;
 +      GET_BUF_U8(op2);
 +      if (op2 == 0 || (op2 & 0xf0)) {
 +        // Spare
 +        edata.cmd = ARM_EXIDX_CMD_RESERVED;
 +      } else {
 +        // Pop integer registers under mask {r3,r2,r1,r0}
 +        edata.cmd = ARM_EXIDX_CMD_REG_POP;
 +        edata.data = op2 & 0x0f;
 +      }
 +    }
 +    else if (op == 0xb2) {
 +      // vsp = vsp + 0x204 + (uleb128 << 2)
 +      uint64_t offset = 0;
 +      uint8_t byte, shift = 0;
 +      do {
 +        GET_BUF_U8(byte);
 +        offset |= (byte & 0x7f) << shift;
 +        shift += 7;
 +      } while ((byte & 0x80) && buf < end);
 +      edata.data = offset * 4 + 0x204;
 +      edata.cmd = ARM_EXIDX_CMD_ADD_TO_VSP;
 +    }
 +    else if (op == 0xb3 || op == 0xc8 || op == 0xc9) {
 +      // b3: Pop VFP regs D[ssss]    to D[ssss+cccc],    FSTMFDX-ishly
 +      // c8: Pop VFP regs D[16+ssss] to D[16+ssss+cccc], FSTMFDD-ishly
 +      // c9: Pop VFP regs D[ssss]    to D[ssss+cccc],    FSTMFDD-ishly
 +      edata.cmd = ARM_EXIDX_CMD_VFP_POP;
 +      GET_BUF_U8(edata.data);
 +      if (op == 0xc8) edata.data |= ARM_EXIDX_VFP_SHIFT_16;
 +      if (op != 0xb3) edata.data |= ARM_EXIDX_VFP_FSTMD;
 +    }
 +    else if ((op & 0xf8) == 0xb8 || (op & 0xf8) == 0xd0) {
 +      // b8: Pop VFP regs D[8] to D[8+nnn], FSTMFDX-ishly
 +      // d0: Pop VFP regs D[8] to D[8+nnn], FSTMFDD-ishly
 +      edata.cmd = ARM_EXIDX_CMD_VFP_POP;
 +      edata.data = 0x80 | (op & 0x07);
 +      if ((op & 0xf8) == 0xd0) edata.data |= ARM_EXIDX_VFP_FSTMD;
 +    }
 +    else if (op >= 0xc0 && op <= 0xc5) {
 +      // Intel Wireless MMX pop wR[10]-wr[10+nnn], nnn != 6,7
 +      edata.cmd = ARM_EXIDX_CMD_WREG_POP;
 +      edata.data = 0xa0 | (op & 0x07);
 +    }
 +    else if (op == 0xc6) {
 +      // Intel Wireless MMX pop wR[ssss] to wR[ssss+cccc]
 +      edata.cmd = ARM_EXIDX_CMD_WREG_POP;
 +      GET_BUF_U8(edata.data);
 +    }
 +    else if (op == 0xc7) {
 +      uint8_t op2;
 +      GET_BUF_U8(op2);
 +      if (op2 == 0 || (op2 & 0xf0)) {
 +        // Spare
 +        edata.cmd = ARM_EXIDX_CMD_RESERVED;
 +      } else {
 +        // Intel Wireless MMX pop wCGR registers under mask {wCGR3,2,1,0}
 +        edata.cmd = ARM_EXIDX_CMD_WCGR_POP;
 +        edata.data = op2 & 0x0f;
 +      }
 +    }
 +    else {
 +      // Spare
 +      edata.cmd = ARM_EXIDX_CMD_RESERVED;
 +    }
 +
 +    int ret = handler_->ImproveStackFrame(&edata);
 +    if (ret < 0) return ret;
 +  }
 +  return 0;
 +
 +# undef GET_BUF_U8
 +}
 +
 +void ExceptionTableInfo::Start()
 +{
 +  const struct exidx_entry* start
 +    = reinterpret_cast<const struct exidx_entry*>(mr_exidx_.data());
 +  const struct exidx_entry* end
 +    = reinterpret_cast<const struct exidx_entry*>(mr_exidx_.data()
 +                                                  + mr_exidx_.length());
 +
 +  // Iterate over each of the EXIDX entries (pairs of 32-bit words).
 +  // These occupy the entire .exidx section.
 +  for (const struct exidx_entry* entry = start; entry < end; ++entry) {
 +
 +    // Figure out the code address range that this table entry is
 +    // associated with.
 +    uint32_t addr = (reinterpret_cast<char*>(Prel31ToAddr(&entry->addr))
 +                     - mapping_addr_ + loading_addr_) & 0x7fffffff;
 +    uint32_t next_addr;
 +    if (entry < end - 1)
 +      next_addr = (reinterpret_cast<char*>(Prel31ToAddr(&((entry + 1)->addr)))
 +                   - mapping_addr_ + loading_addr_) & 0x7fffffff;
 +    else {
 +      // This is the last EXIDX entry in the sequence, so we don't
 +      // have an address for the start of the next function, to limit
 +      // this one.  Instead use the address of the last byte of the
 +      // text section associated with this .exidx section, that we
 +      // have been given.  So as to avoid junking up the CFI unwind
 +      // tables with absurdly large address ranges in the case where
 +      // text_last_svma_ is wrong, only use the value if it is nonzero
 +      // and within one page of |addr|.  Otherwise assume a length of 1.
 +      //
 +      // In some cases, gcc has been observed to finish the exidx
 +      // section with an entry of length 1 marked CANT_UNWIND,
 +      // presumably exactly for the purpose of giving a definite
 +      // length for the last real entry, without having to look at
 +      // text segment boundaries.
 +      bool plausible = false;
 +      next_addr = addr + 1;
 +      if (text_last_svma_ != 0) {
 +        uint32_t maybe_next_addr = text_last_svma_ + 1;
 +        if (maybe_next_addr > addr && maybe_next_addr - addr <= 4096) {
 +          next_addr = maybe_next_addr;
 +          plausible = true;
 +        }
 +      }
 +      if (!plausible)
 +        BPLOG(INFO) << "ExceptionTableInfo: implausible EXIDX last entry size "
 +                    << (int32_t)(text_last_svma_ - addr)
 +                    << "; using 1 instead.";
 +    }
 +
 +    // Extract the unwind info into |buf|.  This might fail for
 +    // various reasons.  It involves reading both the .exidx and
 +    // .extab sections.  All accesses to those sections are
 +    // bounds-checked.
 +    uint8_t buf[ARM_EXIDX_TABLE_LIMIT];
 +    size_t buf_used = 0;
 +    ExExtractResult res = ExtabEntryExtract(entry, buf, sizeof(buf), &buf_used);
 +    if (res != ExSuccess) {
 +      // Couldn't extract the unwind info, for some reason.  Move on.
 +      switch (res) {
 +        case ExInBufOverflow:
 +          BPLOG(INFO) << "ExtabEntryExtract: .exidx/.extab section overrun";
 +          break;
 +        case ExOutBufOverflow:
 +          BPLOG(INFO) << "ExtabEntryExtract: bytecode buffer overflow";
 +          break;
 +        case ExCantUnwind:
 +          BPLOG(INFO) << "ExtabEntryExtract: function is marked CANT_UNWIND";
 +          break;
 +        case ExCantRepresent:
 +          BPLOG(INFO) << "ExtabEntryExtract: bytecode can't be represented";
 +          break;
 +        case ExInvalid:
 +          BPLOG(INFO) << "ExtabEntryExtract: index table entry is invalid";
 +          break;
 +        default:
 +          BPLOG(INFO) << "ExtabEntryExtract: unknown error: " << (int)res;
 +          break;
 +      }
 +      continue;
 +    }
 +
 +    // Finally, work through the unwind instructions in |buf| and
 +    // create CFI entries that Breakpad can use.  This can also fail.
 +    // First, add a new stack frame entry, into which ExtabEntryDecode
 +    // will write the CFI entries.
 +    handler_->AddStackFrame(addr, next_addr - addr);
 +    int ret = ExtabEntryDecode(buf, buf_used);
 +    if (ret < 0) {
 +      handler_->DeleteStackFrame();
 +      BPLOG(INFO) << "ExtabEntryDecode: failed with error code: " << ret;
 +      continue;
 +    }
 +    handler_->SubmitStackFrame();
 +
 +  } /* iterating over .exidx */
 +}
 +
 +} // arm_ex_reader
 diff --git a/src/common/arm_ex_reader.h b/src/common/arm_ex_reader.h
 new file mode 100644
 --- /dev/null
 +++ b/src/common/arm_ex_reader.h
@@ -0,0 +1,115 @@
 +
 +/* libunwind - a platform-independent unwind library
 +   Copyright 2011 Linaro Limited
 +
 +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.  */
 +
 +// Copyright (c) 2010 Google Inc.
 +// All rights reserved.
 +//
 +// Redistribution and use in source and binary forms, with or without
 +// modification, are permitted provided that the following conditions are
 +// met:
 +//
 +//     * Redistributions of source code must retain the above copyright
 +// notice, this list of conditions and the following disclaimer.
 +//     * Redistributions in binary form must reproduce the above
 +// copyright notice, this list of conditions and the following disclaimer
 +// in the documentation and/or other materials provided with the
 +// distribution.
 +//     * Neither the name of Google Inc. nor the names of its
 +// contributors may be used to endorse or promote products derived from
 +// this software without specific prior written permission.
 +//
 +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 +
 +
 +// Derived from libunwind, with extensive modifications.
 +
 +#ifndef COMMON_ARM_EX_READER_H__
 +#define COMMON_ARM_EX_READER_H__
 +
 +#include "common/arm_ex_to_module.h"
 +#include "common/memory_range.h"
 +
 +namespace arm_ex_reader {
 +
 +// This class is a reader for ARM unwind information
 +// from .ARM.exidx and .ARM.extab sections.
 +class ExceptionTableInfo {
 + public:
 +  ExceptionTableInfo(const char* exidx, size_t exidx_size,
 +                     const char* extab, size_t extab_size,
 +                     uint32_t text_last_svma,
 +                     arm_ex_to_module::ARMExToModule* handler,
 +                     const char* mapping_addr,
 +                     uint32_t loading_addr)
 +      : mr_exidx_(google_breakpad::MemoryRange(exidx, exidx_size)),
 +        mr_extab_(google_breakpad::MemoryRange(extab, extab_size)),
 +        text_last_svma_(text_last_svma),
 +        handler_(handler), mapping_addr_(mapping_addr),
 +        loading_addr_(loading_addr) { }
 +
 +  ~ExceptionTableInfo() { }
 +
 +  // Parses the entries in .ARM.exidx and possibly
 +  // in .ARM.extab tables, reports what we find to
 +  // arm_ex_to_module::ARMExToModule.
 +  void Start();
 +
 + private:
 +  google_breakpad::MemoryRange mr_exidx_;
 +  google_breakpad::MemoryRange mr_extab_;
 +  uint32_t text_last_svma_;
 +  arm_ex_to_module::ARMExToModule* handler_;
 +  const char* mapping_addr_;
 +  uint32_t loading_addr_;
 +
 +  enum ExExtractResult {
 +    ExSuccess,        // success
 +    ExInBufOverflow,  // out-of-range while reading .exidx
 +    ExOutBufOverflow, // output buffer is too small
 +    ExCantUnwind,     // this function is marked CANT_UNWIND
 +    ExCantRepresent,  // entry valid, but we can't represent it
 +    ExInvalid         // entry is invalid
 +  };
 +  ExExtractResult
 +    ExtabEntryExtract(const struct arm_ex_to_module::exidx_entry* entry,
 +                      uint8_t* buf, size_t buf_size,
 +                      /*OUT*/size_t* buf_used);
 +
 +  int ExtabEntryDecode(const uint8_t* buf, size_t buf_size);
 +};
 +
 +} // namespace arm_ex_reader
 +
 +#endif // COMMON_ARM_EX_READER_H__
 diff --git a/src/common/arm_ex_to_module.cc b/src/common/arm_ex_to_module.cc
 new file mode 100644
 --- /dev/null
 +++ b/src/common/arm_ex_to_module.cc
@@ -0,0 +1,206 @@
 +
 +/* libunwind - a platform-independent unwind library
 +   Copyright 2011 Linaro Limited
 +
 +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.  */
 +
 +// Copyright (c) 2010 Google Inc.
 +// All rights reserved.
 +//
 +// Redistribution and use in source and binary forms, with or without
 +// modification, are permitted provided that the following conditions are
 +// met:
 +//
 +//     * Redistributions of source code must retain the above copyright
 +// notice, this list of conditions and the following disclaimer.
 +//     * Redistributions in binary form must reproduce the above
 +// copyright notice, this list of conditions and the following disclaimer
 +// in the documentation and/or other materials provided with the
 +// distribution.
 +//     * Neither the name of Google Inc. nor the names of its
 +// contributors may be used to endorse or promote products derived from
 +// this software without specific prior written permission.
 +//
 +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 +
 +
 +// Derived from libunwind, with extensive modifications.
 +
 +#include "common/unique_string.h"
 +#include "common/arm_ex_to_module.h"
 +
 +#include <stdio.h>
 +#include <assert.h>
 +
 +// For big-picture comments on how the EXIDX reader works,
 +// see arm_ex_reader.cc.
 +
 +#define ARM_EXBUF_START(x) (((x) >> 4) & 0x0f)
 +#define ARM_EXBUF_COUNT(x) ((x) & 0x0f)
 +#define ARM_EXBUF_END(x)   (ARM_EXBUF_START(x) + ARM_EXBUF_COUNT(x))
 +
 +using google_breakpad::ustr__pc;
 +using google_breakpad::ustr__lr;
 +using google_breakpad::ustr__sp;
 +using google_breakpad::Module;
 +using google_breakpad::ToUniqueString;
 +using google_breakpad::UniqueString;
 +
 +namespace arm_ex_to_module {
 +
 +// Translate command from extab_data to command for Module.
 +int ARMExToModule::TranslateCmd(const struct extab_data* edata,
 +                                Module::StackFrameEntry* entry, string& vsp) {
 +  int ret = 0;
 +  switch (edata->cmd) {
 +    case ARM_EXIDX_CMD_FINISH:
 +      /* Copy LR to PC if there isn't currently a rule for PC in force. */
 +      if (entry->initial_rules.find(ustr__pc())
 +          == entry->initial_rules.end()) {
 +        if (entry->initial_rules.find(ustr__lr())
 +            == entry->initial_rules.end()) {
 +          entry->initial_rules[ustr__pc()] = Module::Expr("lr");
 +        } else {
 +          entry->initial_rules[ustr__pc()] = entry->initial_rules[ustr__lr()];
 +        }
 +      }
 +      break;
 +    case ARM_EXIDX_CMD_SUB_FROM_VSP:
 +      {
 +        char c[16];
 +        sprintf(c, " %d -", edata->data);
 +        vsp += c;
 +      }
 +      break;
 +    case ARM_EXIDX_CMD_ADD_TO_VSP:
 +      {
 +        char c[16];
 +        sprintf(c, " %d +", edata->data);
 +        vsp += c;
 +      }
 +      break;
 +    case ARM_EXIDX_CMD_REG_POP:
 +      for (unsigned int i = 0; i < 16; i++) {
 +        if (edata->data & (1 << i)) {
 +          entry->initial_rules[ToUniqueString(regnames[i])]
 +            = Module::Expr(vsp + " ^");
 +          vsp += " 4 +";
 +        }
 +      }
 +      /* Set cfa in case the SP got popped. */
 +      if (edata->data & (1 << 13)) {
 +        Module::Expr& vsp_expr = entry->initial_rules[ustr__sp()];
 +        // It must be a postfix expression (we don't generate anything
 +        // else here), so return -1 to fail out if it isn't.
 +        if (!vsp_expr.isExprPostfix()) {
 +          ret = -1;
 +          break;
 +        };
 +        vsp = vsp_expr.getExprPostfix();
 +      }
 +      break;
 +    case ARM_EXIDX_CMD_REG_TO_SP: {
 +      assert (edata->data < 16);
 +      const char* const regname = regnames[edata->data];
 +      const UniqueString* regname_us = ToUniqueString(regname);
 +      if (entry->initial_rules.find(regname_us) == entry->initial_rules.end()) {
 +        entry->initial_rules[ustr__sp()] = Module::Expr(regname);
 +      } else {
 +        entry->initial_rules[ustr__sp()] = entry->initial_rules[regname_us];
 +      }
 +      Module::Expr& vsp_expr = entry->initial_rules[ustr__sp()];
 +      if (!vsp_expr.isExprPostfix()) {
 +        ret = -1;
 +        break;
 +      };
 +      vsp = vsp_expr.getExprPostfix();
 +      break;
 +    }
 +    case ARM_EXIDX_CMD_VFP_POP:
 +      /* Don't recover VFP registers, but be sure to adjust the stack
 +         pointer. */
 +      for (unsigned int i = ARM_EXBUF_START(edata->data);
 +           i <= ARM_EXBUF_END(edata->data); i++) {
 +        vsp += " 8 +";
 +      }
 +      if (!(edata->data & ARM_EXIDX_VFP_FSTMD)) {
 +        vsp += " 4 +";
 +      }
 +      break;
 +    case ARM_EXIDX_CMD_WREG_POP:
 +      for (unsigned int i = ARM_EXBUF_START(edata->data);
 +           i <= ARM_EXBUF_END(edata->data); i++) {
 +        vsp += " 8 +";
 +      }
 +      break;
 +    case ARM_EXIDX_CMD_WCGR_POP:
 +      // Pop wCGR registers under mask {wCGR3,2,1,0}, hence "i < 4"
 +      for (unsigned int i = 0; i < 4; i++) {
 +        if (edata->data & (1 << i)) {
 +          vsp += " 4 +";
 +        }
 +      }
 +      break;
 +    case ARM_EXIDX_CMD_REFUSED:
 +    case ARM_EXIDX_CMD_RESERVED:
 +      ret = -1;
 +      break;
 +  }
 +  return ret;
 +}
 +
 +void ARMExToModule::AddStackFrame(uintptr_t addr, size_t size) {
 +  stack_frame_entry_ = new Module::StackFrameEntry;
 +  stack_frame_entry_->address = addr;
 +  stack_frame_entry_->size = size;
 +  stack_frame_entry_->initial_rules[ToUniqueString(kCFA)] = Module::Expr("sp");
 +  vsp_ = "sp";
 +}
 +
 +int ARMExToModule::ImproveStackFrame(const struct extab_data* edata) {
 +  return TranslateCmd(edata, stack_frame_entry_, vsp_) ;
 +}
 +
 +void ARMExToModule::DeleteStackFrame() {
 +  delete stack_frame_entry_;
 +}
 +
 +void ARMExToModule::SubmitStackFrame() {
 +  // return address always winds up in pc
 +  stack_frame_entry_->initial_rules[ToUniqueString(kRA)]
 +    = stack_frame_entry_->initial_rules[ustr__pc()];
 +  // the final value of vsp is the new value of sp
 +  stack_frame_entry_->initial_rules[ustr__sp()] = vsp_;
 +  module_->AddStackFrameEntry(stack_frame_entry_);
 +}
 +
 +} // namespace arm_ex_to_module
 diff --git a/src/common/arm_ex_to_module.h b/src/common/arm_ex_to_module.h
 new file mode 100644
 --- /dev/null
 +++ b/src/common/arm_ex_to_module.h
@@ -0,0 +1,129 @@
 +
 +/* libunwind - a platform-independent unwind library
 +   Copyright 2011 Linaro Limited
 +
 +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.  */
 +
 +// Copyright (c) 2010 Google Inc.
 +// All rights reserved.
 +//
 +// Redistribution and use in source and binary forms, with or without
 +// modification, are permitted provided that the following conditions are
 +// met:
 +//
 +//     * Redistributions of source code must retain the above copyright
 +// notice, this list of conditions and the following disclaimer.
 +//     * Redistributions in binary form must reproduce the above
 +// copyright notice, this list of conditions and the following disclaimer
 +// in the documentation and/or other materials provided with the
 +// distribution.
 +//     * Neither the name of Google Inc. nor the names of its
 +// contributors may be used to endorse or promote products derived from
 +// this software without specific prior written permission.
 +//
 +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 +
 +
 +// Derived from libunwind, with extensive modifications.
 +
 +#ifndef COMMON_ARM_EX_TO_MODULE__
 +#define COMMON_ARM_EX_TO_MODULE__
 +
 +#include "common/module.h"
 +
 +#include <string.h>
 +
 +namespace arm_ex_to_module {
 +
 +using google_breakpad::Module;
 +
 +typedef enum extab_cmd {
 +  ARM_EXIDX_CMD_FINISH,
 +  ARM_EXIDX_CMD_SUB_FROM_VSP,
 +  ARM_EXIDX_CMD_ADD_TO_VSP,
 +  ARM_EXIDX_CMD_REG_POP,
 +  ARM_EXIDX_CMD_REG_TO_SP,
 +  ARM_EXIDX_CMD_VFP_POP,
 +  ARM_EXIDX_CMD_WREG_POP,
 +  ARM_EXIDX_CMD_WCGR_POP,
 +  ARM_EXIDX_CMD_RESERVED,
 +  ARM_EXIDX_CMD_REFUSED,
 +} extab_cmd_t;
 +
 +struct exidx_entry {
 +  uint32_t addr;
 +  uint32_t data;
 +};
 +
 +struct extab_data {
 +  extab_cmd_t cmd;
 +  uint32_t data;
 +};
 +
 +enum extab_cmd_flags {
 +  ARM_EXIDX_VFP_SHIFT_16 = 1 << 16,
 +  ARM_EXIDX_VFP_FSTMD = 1 << 17, // distinguishes FSTMxxD from FSTMxxX
 +};
 +
 +const string kRA = ".ra";
 +const string kCFA = ".cfa";
 +
 +static const char* const regnames[] = {
 + "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
 + "r8", "r9", "r10", "r11", "r12", "sp", "lr", "pc",
 + "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7",
 + "fps", "cpsr"
 +};
 +
 +// Receives information from arm_ex_reader::ExceptionTableInfo
 +// and adds it to the Module object
 +class ARMExToModule {
 + public:
 +  ARMExToModule(Module* module)
 +      : module_(module) { }
 +  ~ARMExToModule() { }
 +  void AddStackFrame(uintptr_t addr, size_t size);
 +  int ImproveStackFrame(const struct extab_data* edata);
 +  void DeleteStackFrame();
 +  void SubmitStackFrame();
 + private:
 +  Module* module_;
 +  Module::StackFrameEntry* stack_frame_entry_;
 +  string vsp_;
 +  int TranslateCmd(const struct extab_data* edata,
 +                   Module::StackFrameEntry* entry,
 +                   string& vsp);
 +};
 +
 +} // namespace arm_ex_to_module
 +
 +#endif // COMMON_ARM_EX_TO_MODULE__
 diff --git a/src/common/linux/dump_symbols.cc b/src/common/linux/dump_symbols.cc
 --- a/src/common/linux/dump_symbols.cc
 +++ b/src/common/linux/dump_symbols.cc
@@ -47,16 +47,17 @@
  #include <unistd.h>
  #include <iostream>
  #include <set>
  #include <string>
  #include <utility>
  #include <vector>
 +#include "common/arm_ex_reader.h"
  #include "common/dwarf/bytereader-inl.h"
  #include "common/dwarf/dwarf2diehandler.h"
  #include "common/dwarf_cfi_to_module.h"
  #include "common/dwarf_cu_to_module.h"
  #include "common/dwarf_line_to_module.h"
  #include "common/linux/elfutils.h"
  #include "common/linux/elfutils-inl.h"
  #include "common/linux/elf_symbols_to_module.h"
@@ -65,16 +66,20 @@
  #include "common/scoped_ptr.h"
  #ifndef NO_STABS_SUPPORT
  #include "common/stabs_reader.h"
  #include "common/stabs_to_module.h"
  #endif
  #include "common/using_std_string.h"
  #include "common/logging.h"
 +#if defined(__ANDROID__) && !defined(SHT_ARM_EXIDX)
 +# define SHT_ARM_EXIDX (SHT_LOPROC + 1)
 +#endif
 +
  // This namespace contains helper functions.
  namespace {
  using google_breakpad::DwarfCFIToModule;
  using google_breakpad::DwarfCUToModule;
  using google_breakpad::DwarfLineToModule;
  using google_breakpad::ElfClass;
  using google_breakpad::ElfClass32;
@@ -340,16 +345,62 @@ bool LoadDwarfCFI(const string& dwarf_fi
                                                         section_name);
    dwarf2reader::CallFrameInfo parser(cfi, cfi_size,
                                       &byte_reader, &handler, &dwarf_reporter,
                                       eh_frame);
    parser.Start();
    return true;
  }
 +template<typename ElfClass>
 +bool LoadARMexidx(const typename ElfClass::Ehdr* elf_header,
 +                  const typename ElfClass::Shdr* exidx_section,
 +                  const typename ElfClass::Shdr* extab_section,
 +                  uint32_t loading_addr,
 +                  Module* module) {
 +  // To do this properly we need to know:
 +  // * the bounds of the .ARM.exidx section in the mapped image
 +  // * the bounds of the .ARM.extab section in the mapped image
 +  // * the vma of the last byte in the text section associated with the .exidx
 +  // The first two are easy.  The third is a bit tricky.  If we can't
 +  // figure out what it is, just pass in zero.
 +  const char *exidx_img
 +    = GetOffset<ElfClass, char>(elf_header, exidx_section->sh_offset);
 +  size_t exidx_size = exidx_section->sh_size;
 +  const char *extab_img
 +    = GetOffset<ElfClass, char>(elf_header, extab_section->sh_offset);
 +  size_t extab_size = extab_section->sh_size;
 +
 +  // The sh_link field of the exidx section gives the section number
 +  // for the associated text section.
 +  uint32_t exidx_text_last_svma = 0;
 +  int exidx_text_sno = exidx_section->sh_link;
 +  typedef typename ElfClass::Shdr Shdr;
 +  // |sections| points to the section header table
 +  const Shdr* sections
 +    = GetOffset<ElfClass, Shdr>(elf_header, elf_header->e_shoff);
 +  const int num_sections = elf_header->e_shnum;
 +  if (exidx_text_sno >= 0 && exidx_text_sno < num_sections) {
 +    const Shdr* exidx_text_shdr = &sections[exidx_text_sno];
 +    if (exidx_text_shdr->sh_size > 0) {
 +      exidx_text_last_svma
 +        = exidx_text_shdr->sh_addr + exidx_text_shdr->sh_size - 1;
 +    }
 +  }
 +
 +  arm_ex_to_module::ARMExToModule handler(module);
 +  arm_ex_reader::ExceptionTableInfo
 +    parser(exidx_img, exidx_size, extab_img, extab_size, exidx_text_last_svma,
 +           &handler,
 +           reinterpret_cast<const char*>(elf_header),
 +           loading_addr);
 +  parser.Start();
 +  return true;
 +}
 +
  bool LoadELF(const string& obj_file, MmapWrapper* map_wrapper,
               void** elf_header) {
    int obj_fd = open(obj_file.c_str(), O_RDONLY);
    if (obj_fd < 0) {
      fprintf(stderr, "Failed to open ELF file '%s': %s\n",
              obj_file.c_str(), strerror(errno));
      return false;
    }
@@ -629,16 +680,39 @@ bool LoadSymbols(const string& obj_file,
                                   eh_frame_section, true,
                                   got_section, text_section, big_endian, module);
        found_usable_info = found_usable_info || result;
        if (result)
          BPLOG(INFO) << "LoadSymbols:   read CFI from .eh_frame";
      }
    }
 +  // ARM has special unwind tables that can be used.
 +  const Shdr* arm_exidx_section =
 +      FindElfSectionByName<ElfClass>(".ARM.exidx", SHT_ARM_EXIDX,
 +                                     sections, names, names_end,
 +                                     elf_header->e_shnum);
 +  const Shdr* arm_extab_section =
 +      FindElfSectionByName<ElfClass>(".ARM.extab", SHT_PROGBITS,
 +                                     sections, names, names_end,
 +                                     elf_header->e_shnum);
 +  // Only load information from this section if there isn't a .debug_info
 +  // section.
 +  if (!found_debug_info_section
 +      && arm_exidx_section && arm_extab_section && symbol_data != NO_CFI) {
 +    info->LoadedSection(".ARM.exidx");
 +    info->LoadedSection(".ARM.extab");
 +    bool result = LoadARMexidx<ElfClass>(elf_header,
 +                                         arm_exidx_section, arm_extab_section,
 +                                         loading_addr, module);
 +    found_usable_info = found_usable_info || result;
 +    if (result)
 +      BPLOG(INFO) << "LoadSymbols:   read EXIDX from .ARM.{exidx,extab}";
 +  }
 +
    if (!found_debug_info_section && symbol_data != ONLY_CFI) {
      fprintf(stderr, "%s: file contains no debugging information"
              " (no \".stab\" or \".debug_info\" sections)\n",
              obj_file.c_str());
      // Failed, but maybe there's a .gnu_debuglink section?
      if (read_gnu_debug_link) {
        const Shdr* gnu_debuglink_section
 diff --git a/src/common/module.cc b/src/common/module.cc
 --- a/src/common/module.cc
 +++ b/src/common/module.cc
@@ -253,17 +253,17 @@ void Module::AssignSourceIds() {
  bool Module::ReportError() {
    fprintf(stderr, "error writing symbol file: %s\n",
            strerror(errno));
    return false;
  }
  std::ostream& operator<<(std::ostream& stream, const Module::Expr& expr) {
 -  assert(!expr.invalid());
 +  assert(!expr.isExprInvalid());
    switch (expr.how_) {
      case Module::kExprSimple:
        stream << FromUniqueString(expr.ident_) << " " << expr.offset_ << " +";
        break;
      case Module::kExprSimpleMem:
        stream << FromUniqueString(expr.ident_) << " " << expr.offset_ << " + ^";
        break;
      case Module::kExprPostfix:
 diff --git a/src/common/module.h b/src/common/module.h
 --- a/src/common/module.h
 +++ b/src/common/module.h
@@ -160,17 +160,24 @@ class Module {
      }
      // Construct an invalid expression
      Expr() {
        postfix_ = "";
        ident_ = NULL;
        offset_ = 0;
        how_ = kExprInvalid;
      }
 -    bool invalid() const { return how_ == kExprInvalid; }
 +    bool isExprInvalid() const { return how_ == kExprInvalid; }
 +    bool isExprPostfix() const { return how_ == kExprPostfix; }
 +
 +    // Return the postfix expression string.  This is only
 +    // meaningful on Exprs for which isExprPostfix returns true.
 +    // In all other cases it returns an empty string.
 +    string getExprPostfix() const { return postfix_; }
 +
      bool operator==(const Expr& other) const {
        return how_ == other.how_ &&
            ident_ == other.ident_ &&
            offset_ == other.offset_ &&
            postfix_ == other.postfix_;
      }
      // The identifier that gives the starting value for simple expressions.
 diff --git a/src/common/unique_string.h b/src/common/unique_string.h
 --- a/src/common/unique_string.h
 +++ b/src/common/unique_string.h
@@ -230,16 +230,37 @@ inline static const UniqueString* ustr__
  // ".ra"
  inline static const UniqueString* ustr__ZDra() {
    static const UniqueString* us = NULL;
    if (!us) us = ToUniqueString(".ra");
    return us;
  }
 +// "pc"
 +inline static const UniqueString* ustr__pc() {
 +  static const UniqueString* us = NULL;
 +  if (!us) us = ToUniqueString("pc");
 +  return us;
 +}
 +
 +// "lr"
 +inline static const UniqueString* ustr__lr() {
 +  static const UniqueString* us = NULL;
 +  if (!us) us = ToUniqueString("lr");
 +  return us;
 +}
 +
 +// "sp"
 +inline static const UniqueString* ustr__sp() {
 +  static const UniqueString* us = NULL;
 +  if (!us) us = ToUniqueString("sp");
 +  return us;
 +}
 +
  template <typename ValueType>
  class UniqueStringMap
  {
   private:
    static const int N_FIXED = 10;
   public:
    UniqueStringMap() : n_fixed_(0), n_sets_(0), n_gets_(0), n_clears_(0) {};
 diff --git a/src/processor/cfi_frame_info.cc b/src/processor/cfi_frame_info.cc
 --- a/src/processor/cfi_frame_info.cc
 +++ b/src/processor/cfi_frame_info.cc
@@ -49,17 +49,17 @@ namespace google_breakpad {
  #endif
  template<typename V>
  bool CFIFrameInfo::FindCallerRegs(const RegisterValueMap<V> &registers,
                                    const MemoryRegion &memory,
                                    RegisterValueMap<V> *caller_registers) const {
    // If there are not rules for both .ra and .cfa in effect at this address,
    // don't use this CFI data for stack walking.
 -  if (cfa_rule_.invalid() || ra_rule_.invalid())
 +  if (cfa_rule_.isExprInvalid() || ra_rule_.isExprInvalid())
      return false;
    RegisterValueMap<V> working;
    PostfixEvaluator<V> evaluator(&working, &memory);
    caller_registers->clear();
    // First, compute the CFA.
@@ -100,20 +100,20 @@ template bool CFIFrameInfo::FindCallerRe
  template bool CFIFrameInfo::FindCallerRegs<uint64_t>(
      const RegisterValueMap<uint64_t> &registers,
      const MemoryRegion &memory,
      RegisterValueMap<uint64_t> *caller_registers) const;
  string CFIFrameInfo::Serialize() const {
    std::ostringstream stream;
 -  if (!cfa_rule_.invalid()) {
 +  if (!cfa_rule_.isExprInvalid()) {
      stream << ".cfa: " << cfa_rule_;
    }
 -  if (!ra_rule_.invalid()) {
 +  if (!ra_rule_.isExprInvalid()) {
      if (static_cast<std::streamoff>(stream.tellp()) != 0)
        stream << " ";
      stream << ".ra: " << ra_rule_;
    }
    // Visit the register rules in alphabetical order.  Because
    // register_rules_ has the elements in some arbitrary order,
    // get the names out into a vector, sort them, and visit in

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toolkit/crashreporter/breakpad-patches/12-bug863475.patch@6474c204b198 (annotated)

toolkit/crashreporter/breakpad-patches/12-bug863475.patch