The Tor Browser: tools/profiler/LulDwarfExt.h@97036ab72558 (annotated)

tools/profiler/LulDwarfExt.h@97036ab72558 (annotated)

tools/profiler/LulDwarfExt.h

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 // Copyright 2006, 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.
 // Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
 // This file is derived from the following files in
 // toolkit/crashreporter/google-breakpad:
 //   src/common/dwarf/types.h
 //   src/common/dwarf/dwarf2enums.h
 //   src/common/dwarf/bytereader.h
 //   src/common/dwarf_cfi_to_module.h
 //   src/common/dwarf/dwarf2reader.h
 #ifndef LulDwarfExt_h
 #define LulDwarfExt_h
 #include <stdint.h>
 #include "mozilla/Assertions.h"
 #include "LulDwarfSummariser.h"
 typedef signed char         int8;
 typedef short               int16;
 typedef int                 int32;
 typedef long long           int64;
 typedef unsigned char      uint8;
 typedef unsigned short     uint16;
 typedef unsigned int       uint32;
 typedef unsigned long long uint64;
 #ifdef __PTRDIFF_TYPE__
 typedef          __PTRDIFF_TYPE__ intptr;
 typedef unsigned __PTRDIFF_TYPE__ uintptr;
 #else
 #error "Can't find pointer-sized integral types."
 #endif
 namespace lul {
 // Exception handling frame description pointer formats, as described
 // by the Linux Standard Base Core Specification 4.0, section 11.5,
 // DWARF Extensions.
 enum DwarfPointerEncoding
   {
     DW_EH_PE_absptr	= 0x00,
     DW_EH_PE_omit	= 0xff,
     DW_EH_PE_uleb128    = 0x01,
     DW_EH_PE_udata2	= 0x02,
     DW_EH_PE_udata4	= 0x03,
     DW_EH_PE_udata8	= 0x04,
     DW_EH_PE_sleb128    = 0x09,
     DW_EH_PE_sdata2	= 0x0A,
     DW_EH_PE_sdata4	= 0x0B,
     DW_EH_PE_sdata8	= 0x0C,
     DW_EH_PE_pcrel	= 0x10,
     DW_EH_PE_textrel	= 0x20,
     DW_EH_PE_datarel	= 0x30,
     DW_EH_PE_funcrel	= 0x40,
     DW_EH_PE_aligned	= 0x50,
     // The GNU toolchain sources define this enum value as well,
     // simply to help classify the lower nybble values into signed and
     // unsigned groups.
     DW_EH_PE_signed	= 0x08,
     // This is not documented in LSB 4.0, but it is used in both the
     // Linux and OS X toolchains. It can be added to any other
     // encoding (except DW_EH_PE_aligned), and indicates that the
     // encoded value represents the address at which the true address
     // is stored, not the true address itself.
     DW_EH_PE_indirect	= 0x80
   };
 // We can't use the obvious name of LITTLE_ENDIAN and BIG_ENDIAN
 // because it conflicts with a macro
 enum Endianness {
   ENDIANNESS_BIG,
   ENDIANNESS_LITTLE
 };
 // A ByteReader knows how to read single- and multi-byte values of
 // various endiannesses, sizes, and encodings, as used in DWARF
 // debugging information and Linux C++ exception handling data.
 class ByteReader {
  public:
   // Construct a ByteReader capable of reading one-, two-, four-, and
   // eight-byte values according to ENDIANNESS, absolute machine-sized
   // addresses, DWARF-style "initial length" values, signed and
   // unsigned LEB128 numbers, and Linux C++ exception handling data's
   // encoded pointers.
   explicit ByteReader(enum Endianness endianness);
   virtual ~ByteReader();
   // Read a single byte from BUFFER and return it as an unsigned 8 bit
   // number.
   uint8 ReadOneByte(const char* buffer) const;
   // Read two bytes from BUFFER and return them as an unsigned 16 bit
   // number, using this ByteReader's endianness.
   uint16 ReadTwoBytes(const char* buffer) const;
   // Read four bytes from BUFFER and return them as an unsigned 32 bit
   // number, using this ByteReader's endianness. This function returns
   // a uint64 so that it is compatible with ReadAddress and
   // ReadOffset. The number it returns will never be outside the range
   // of an unsigned 32 bit integer.
   uint64 ReadFourBytes(const char* buffer) const;
   // Read eight bytes from BUFFER and return them as an unsigned 64
   // bit number, using this ByteReader's endianness.
   uint64 ReadEightBytes(const char* buffer) const;
   // Read an unsigned LEB128 (Little Endian Base 128) number from
   // BUFFER and return it as an unsigned 64 bit integer. Set LEN to
   // the number of bytes read.
   //
   // The unsigned LEB128 representation of an integer N is a variable
   // number of bytes:
   //
   // - If N is between 0 and 0x7f, then its unsigned LEB128
   //   representation is a single byte whose value is N.
   //
   // - Otherwise, its unsigned LEB128 representation is (N & 0x7f) |
   //   0x80, followed by the unsigned LEB128 representation of N /
   //   128, rounded towards negative infinity.
   //
   // In other words, we break VALUE into groups of seven bits, put
   // them in little-endian order, and then write them as eight-bit
   // bytes with the high bit on all but the last.
   uint64 ReadUnsignedLEB128(const char* buffer, size_t* len) const;
   // Read a signed LEB128 number from BUFFER and return it as an
   // signed 64 bit integer. Set LEN to the number of bytes read.
   //
   // The signed LEB128 representation of an integer N is a variable
   // number of bytes:
   //
   // - If N is between -0x40 and 0x3f, then its signed LEB128
   //   representation is a single byte whose value is N in two's
   //   complement.
   //
   // - Otherwise, its signed LEB128 representation is (N & 0x7f) |
   //   0x80, followed by the signed LEB128 representation of N / 128,
   //   rounded towards negative infinity.
   //
   // In other words, we break VALUE into groups of seven bits, put
   // them in little-endian order, and then write them as eight-bit
   // bytes with the high bit on all but the last.
   int64 ReadSignedLEB128(const char* buffer, size_t* len) const;
   // Indicate that addresses on this architecture are SIZE bytes long. SIZE
   // must be either 4 or 8. (DWARF allows addresses to be any number of
   // bytes in length from 1 to 255, but we only support 32- and 64-bit
   // addresses at the moment.) You must call this before using the
   // ReadAddress member function.
   //
   // For data in a .debug_info section, or something that .debug_info
   // refers to like line number or macro data, the compilation unit
   // header's address_size field indicates the address size to use. Call
   // frame information doesn't indicate its address size (a shortcoming of
   // the spec); you must supply the appropriate size based on the
   // architecture of the target machine.
   void SetAddressSize(uint8 size);
   // Return the current address size, in bytes. This is either 4,
   // indicating 32-bit addresses, or 8, indicating 64-bit addresses.
   uint8 AddressSize() const { return address_size_; }
   // Read an address from BUFFER and return it as an unsigned 64 bit
   // integer, respecting this ByteReader's endianness and address size. You
   // must call SetAddressSize before calling this function.
   uint64 ReadAddress(const char* buffer) const;
   // DWARF actually defines two slightly different formats: 32-bit DWARF
   // and 64-bit DWARF. This is *not* related to the size of registers or
   // addresses on the target machine; it refers only to the size of section
   // offsets and data lengths appearing in the DWARF data. One only needs
   // 64-bit DWARF when the debugging data itself is larger than 4GiB.
   // 32-bit DWARF can handle x86_64 or PPC64 code just fine, unless the
   // debugging data itself is very large.
   //
   // DWARF information identifies itself as 32-bit or 64-bit DWARF: each
   // compilation unit and call frame information entry begins with an
   // "initial length" field, which, in addition to giving the length of the
   // data, also indicates the size of section offsets and lengths appearing
   // in that data. The ReadInitialLength member function, below, reads an
   // initial length and sets the ByteReader's offset size as a side effect.
   // Thus, in the normal process of reading DWARF data, the appropriate
   // offset size is set automatically. So, you should only need to call
   // SetOffsetSize if you are using the same ByteReader to jump from the
   // midst of one block of DWARF data into another.
   // Read a DWARF "initial length" field from START, and return it as
   // an unsigned 64 bit integer, respecting this ByteReader's
   // endianness. Set *LEN to the length of the initial length in
   // bytes, either four or twelve. As a side effect, set this
   // ByteReader's offset size to either 4 (if we see a 32-bit DWARF
   // initial length) or 8 (if we see a 64-bit DWARF initial length).
   //
   // A DWARF initial length is either:
   //
   // - a byte count stored as an unsigned 32-bit value less than
   //   0xffffff00, indicating that the data whose length is being
   //   measured uses the 32-bit DWARF format, or
   //
   // - The 32-bit value 0xffffffff, followed by a 64-bit byte count,
   //   indicating that the data whose length is being measured uses
   //   the 64-bit DWARF format.
   uint64 ReadInitialLength(const char* start, size_t* len);
   // Read an offset from BUFFER and return it as an unsigned 64 bit
   // integer, respecting the ByteReader's endianness. In 32-bit DWARF, the
   // offset is 4 bytes long; in 64-bit DWARF, the offset is eight bytes
   // long. You must call ReadInitialLength or SetOffsetSize before calling
   // this function; see the comments above for details.
   uint64 ReadOffset(const char* buffer) const;
   // Return the current offset size, in bytes.
   // A return value of 4 indicates that we are reading 32-bit DWARF.
   // A return value of 8 indicates that we are reading 64-bit DWARF.
   uint8 OffsetSize() const { return offset_size_; }
   // Indicate that section offsets and lengths are SIZE bytes long. SIZE
   // must be either 4 (meaning 32-bit DWARF) or 8 (meaning 64-bit DWARF).
   // Usually, you should not call this function yourself; instead, let a
   // call to ReadInitialLength establish the data's offset size
   // automatically.
   void SetOffsetSize(uint8 size);
   // The Linux C++ ABI uses a variant of DWARF call frame information
   // for exception handling. This data is included in the program's
   // address space as the ".eh_frame" section, and intepreted at
   // runtime to walk the stack, find exception handlers, and run
   // cleanup code. The format is mostly the same as DWARF CFI, with
   // some adjustments made to provide the additional
   // exception-handling data, and to make the data easier to work with
   // in memory --- for example, to allow it to be placed in read-only
   // memory even when describing position-independent code.
   //
   // In particular, exception handling data can select a number of
   // different encodings for pointers that appear in the data, as
   // described by the DwarfPointerEncoding enum. There are actually
   // four axes(!) to the encoding:
   //
   // - The pointer size: pointers can be 2, 4, or 8 bytes long, or use
   //   the DWARF LEB128 encoding.
   //
   // - The pointer's signedness: pointers can be signed or unsigned.
   //
   // - The pointer's base address: the data stored in the exception
   //   handling data can be the actual address (that is, an absolute
   //   pointer), or relative to one of a number of different base
   //   addreses --- including that of the encoded pointer itself, for
   //   a form of "pc-relative" addressing.
   //
   // - The pointer may be indirect: it may be the address where the
   //   true pointer is stored. (This is used to refer to things via
   //   global offset table entries, program linkage table entries, or
   //   other tricks used in position-independent code.)
   //
   // There are also two options that fall outside that matrix
   // altogether: the pointer may be omitted, or it may have padding to
   // align it on an appropriate address boundary. (That last option
   // may seem like it should be just another axis, but it is not.)
   // Indicate that the exception handling data is loaded starting at
   // SECTION_BASE, and that the start of its buffer in our own memory
   // is BUFFER_BASE. This allows us to find the address that a given
   // byte in our buffer would have when loaded into the program the
   // data describes. We need this to resolve DW_EH_PE_pcrel pointers.
   void SetCFIDataBase(uint64 section_base, const char *buffer_base);
   // Indicate that the base address of the program's ".text" section
   // is TEXT_BASE. We need this to resolve DW_EH_PE_textrel pointers.
   void SetTextBase(uint64 text_base);
   // Indicate that the base address for DW_EH_PE_datarel pointers is
   // DATA_BASE. The proper value depends on the ABI; it is usually the
   // address of the global offset table, held in a designated register in
   // position-independent code. You will need to look at the startup code
   // for the target system to be sure. I tried; my eyes bled.
   void SetDataBase(uint64 data_base);
   // Indicate that the base address for the FDE we are processing is
   // FUNCTION_BASE. This is the start address of DW_EH_PE_funcrel
   // pointers. (This encoding does not seem to be used by the GNU
   // toolchain.)
   void SetFunctionBase(uint64 function_base);
   // Indicate that we are no longer processing any FDE, so any use of
   // a DW_EH_PE_funcrel encoding is an error.
   void ClearFunctionBase();
   // Return true if ENCODING is a valid pointer encoding.
   bool ValidEncoding(DwarfPointerEncoding encoding) const;
   // Return true if we have all the information we need to read a
   // pointer that uses ENCODING. This checks that the appropriate
   // SetFooBase function for ENCODING has been called.
   bool UsableEncoding(DwarfPointerEncoding encoding) const;
   // Read an encoded pointer from BUFFER using ENCODING; return the
   // absolute address it represents, and set *LEN to the pointer's
   // length in bytes, including any padding for aligned pointers.
   //
   // This function calls 'abort' if ENCODING is invalid or refers to a
   // base address this reader hasn't been given, so you should check
   // with ValidEncoding and UsableEncoding first if you would rather
   // die in a more helpful way.
   uint64 ReadEncodedPointer(const char *buffer, DwarfPointerEncoding encoding,
                             size_t *len) const;
  private:
   // Function pointer type for our address and offset readers.
   typedef uint64 (ByteReader::*AddressReader)(const char*) const;
   // Read an offset from BUFFER and return it as an unsigned 64 bit
   // integer.  DWARF2/3 define offsets as either 4 or 8 bytes,
   // generally depending on the amount of DWARF2/3 info present.
   // This function pointer gets set by SetOffsetSize.
   AddressReader offset_reader_;
   // Read an address from BUFFER and return it as an unsigned 64 bit
   // integer.  DWARF2/3 allow addresses to be any size from 0-255
   // bytes currently.  Internally we support 4 and 8 byte addresses,
   // and will CHECK on anything else.
   // This function pointer gets set by SetAddressSize.
   AddressReader address_reader_;
   Endianness endian_;
   uint8 address_size_;
   uint8 offset_size_;
   // Base addresses for Linux C++ exception handling data's encoded pointers.
   bool have_section_base_, have_text_base_, have_data_base_;
   bool have_function_base_;
   uint64 section_base_;
   uint64 text_base_, data_base_, function_base_;
   const char *buffer_base_;
 };
 inline uint8 ByteReader::ReadOneByte(const char* buffer) const {
   return buffer[0];
 }
 inline uint16 ByteReader::ReadTwoBytes(const char* signed_buffer) const {
   const unsigned char *buffer
     = reinterpret_cast<const unsigned char *>(signed_buffer);
   const uint16 buffer0 = buffer[0];
   const uint16 buffer1 = buffer[1];
   if (endian_ == ENDIANNESS_LITTLE) {
     return buffer0 | buffer1 << 8;
   } else {
     return buffer1 | buffer0 << 8;
   }
 }
 inline uint64 ByteReader::ReadFourBytes(const char* signed_buffer) const {
   const unsigned char *buffer
     = reinterpret_cast<const unsigned char *>(signed_buffer);
   const uint32 buffer0 = buffer[0];
   const uint32 buffer1 = buffer[1];
   const uint32 buffer2 = buffer[2];
   const uint32 buffer3 = buffer[3];
   if (endian_ == ENDIANNESS_LITTLE) {
     return buffer0 | buffer1 << 8 | buffer2 << 16 | buffer3 << 24;
   } else {
     return buffer3 | buffer2 << 8 | buffer1 << 16 | buffer0 << 24;
   }
 }
 inline uint64 ByteReader::ReadEightBytes(const char* signed_buffer) const {
   const unsigned char *buffer
     = reinterpret_cast<const unsigned char *>(signed_buffer);
   const uint64 buffer0 = buffer[0];
   const uint64 buffer1 = buffer[1];
   const uint64 buffer2 = buffer[2];
   const uint64 buffer3 = buffer[3];
   const uint64 buffer4 = buffer[4];
   const uint64 buffer5 = buffer[5];
   const uint64 buffer6 = buffer[6];
   const uint64 buffer7 = buffer[7];
   if (endian_ == ENDIANNESS_LITTLE) {
     return buffer0 | buffer1 << 8 | buffer2 << 16 | buffer3 << 24 |
       buffer4 << 32 | buffer5 << 40 | buffer6 << 48 | buffer7 << 56;
   } else {
     return buffer7 | buffer6 << 8 | buffer5 << 16 | buffer4 << 24 |
       buffer3 << 32 | buffer2 << 40 | buffer1 << 48 | buffer0 << 56;
   }
 }
 // Read an unsigned LEB128 number.  Each byte contains 7 bits of
 // information, plus one bit saying whether the number continues or
 // not.
 inline uint64 ByteReader::ReadUnsignedLEB128(const char* buffer,
                                              size_t* len) const {
   uint64 result = 0;
   size_t num_read = 0;
   unsigned int shift = 0;
   unsigned char byte;
   do {
     byte = *buffer++;
     num_read++;
     result |= (static_cast<uint64>(byte & 0x7f)) << shift;
     shift += 7;
   } while (byte & 0x80);
   *len = num_read;
   return result;
 }
 // Read a signed LEB128 number.  These are like regular LEB128
 // numbers, except the last byte may have a sign bit set.
 inline int64 ByteReader::ReadSignedLEB128(const char* buffer,
                                           size_t* len) const {
   int64 result = 0;
   unsigned int shift = 0;
   size_t num_read = 0;
   unsigned char byte;
   do {
       byte = *buffer++;
       num_read++;
       result |= (static_cast<uint64>(byte & 0x7f) << shift);
       shift += 7;
   } while (byte & 0x80);
   if ((shift < 8 * sizeof (result)) && (byte & 0x40))
     result |= -((static_cast<int64>(1)) << shift);
   *len = num_read;
   return result;
 }
 inline uint64 ByteReader::ReadOffset(const char* buffer) const {
   MOZ_ASSERT(this->offset_reader_);
   return (this->*offset_reader_)(buffer);
 }
 inline uint64 ByteReader::ReadAddress(const char* buffer) const {
   MOZ_ASSERT(this->address_reader_);
   return (this->*address_reader_)(buffer);
 }
 inline void ByteReader::SetCFIDataBase(uint64 section_base,
                                        const char *buffer_base) {
   section_base_ = section_base;
   buffer_base_ = buffer_base;
   have_section_base_ = true;
 }
 inline void ByteReader::SetTextBase(uint64 text_base) {
   text_base_ = text_base;
   have_text_base_ = true;
 }
 inline void ByteReader::SetDataBase(uint64 data_base) {
   data_base_ = data_base;
   have_data_base_ = true;
 }
 inline void ByteReader::SetFunctionBase(uint64 function_base) {
   function_base_ = function_base;
   have_function_base_ = true;
 }
 inline void ByteReader::ClearFunctionBase() {
   have_function_base_ = false;
 }
 // (derived from)
 // dwarf_cfi_to_module.h: Define the DwarfCFIToModule class, which
 // accepts parsed DWARF call frame info and adds it to a Summariser object.
 // This class is a reader for DWARF's Call Frame Information.  CFI
 // describes how to unwind stack frames --- even for functions that do
 // not follow fixed conventions for saving registers, whose frame size
 // varies as they execute, etc.
 //
 // CFI describes, at each machine instruction, how to compute the
 // stack frame's base address, how to find the return address, and
 // where to find the saved values of the caller's registers (if the
 // callee has stashed them somewhere to free up the registers for its
 // own use).
 //
 // For example, suppose we have a function whose machine code looks
 // like this (imagine an assembly language that looks like C, for a
 // machine with 32-bit registers, and a stack that grows towards lower
 // addresses):
 //
 // func:                                ; entry point; return address at sp
 // func+0:      sp = sp - 16            ; allocate space for stack frame
 // func+1:      sp[12] = r0             ; save r0 at sp+12
 // ...                                  ; other code, not frame-related
 // func+10:     sp -= 4; *sp = x        ; push some x on the stack
 // ...                                  ; other code, not frame-related
 // func+20:     r0 = sp[16]             ; restore saved r0
 // func+21:     sp += 20                ; pop whole stack frame
 // func+22:     pc = *sp; sp += 4       ; pop return address and jump to it
 //
 // DWARF CFI is (a very compressed representation of) a table with a
 // row for each machine instruction address and a column for each
 // register showing how to restore it, if possible.
 //
 // A special column named "CFA", for "Canonical Frame Address", tells how
 // to compute the base address of the frame; registers' entries may
 // refer to the CFA in describing where the registers are saved.
 //
 // Another special column, named "RA", represents the return address.
 //
 // For example, here is a complete (uncompressed) table describing the
 // function above:
 //
 //     insn      cfa    r0      r1 ...  ra
 //     =======================================
 //     func+0:   sp                     cfa[0]
 //     func+1:   sp+16                  cfa[0]
 //     func+2:   sp+16  cfa[-4]         cfa[0]
 //     func+11:  sp+20  cfa[-4]         cfa[0]
 //     func+21:  sp+20                  cfa[0]
 //     func+22:  sp                     cfa[0]
 //
 // Some things to note here:
 //
 // - Each row describes the state of affairs *before* executing the
 //   instruction at the given address.  Thus, the row for func+0
 //   describes the state before we allocate the stack frame.  In the
 //   next row, the formula for computing the CFA has changed,
 //   reflecting that allocation.
 //
 // - The other entries are written in terms of the CFA; this allows
 //   them to remain unchanged as the stack pointer gets bumped around.
 //   For example, the rule for recovering the return address (the "ra"
 //   column) remains unchanged throughout the function, even as the
 //   stack pointer takes on three different offsets from the return
 //   address.
 //
 // - Although we haven't shown it, most calling conventions designate
 //   "callee-saves" and "caller-saves" registers. The callee must
 //   preserve the values of callee-saves registers; if it uses them,
 //   it must save their original values somewhere, and restore them
 //   before it returns. In contrast, the callee is free to trash
 //   caller-saves registers; if the callee uses these, it will
 //   probably not bother to save them anywhere, and the CFI will
 //   probably mark their values as "unrecoverable".
 //
 //   (However, since the caller cannot assume the callee was going to
 //   save them, caller-saves registers are probably dead in the caller
 //   anyway, so compilers usually don't generate CFA for caller-saves
 //   registers.)
 //
 // - Exactly where the CFA points is a matter of convention that
 //   depends on the architecture and ABI in use. In the example, the
 //   CFA is the value the stack pointer had upon entry to the
 //   function, pointing at the saved return address. But on the x86,
 //   the call frame information generated by GCC follows the
 //   convention that the CFA is the address *after* the saved return
 //   address.
 //
 //   But by definition, the CFA remains constant throughout the
 //   lifetime of the frame. This makes it a useful value for other
 //   columns to refer to. It is also gives debuggers a useful handle
 //   for identifying a frame.
 //
 // If you look at the table above, you'll notice that a given entry is
 // often the same as the one immediately above it: most instructions
 // change only one or two aspects of the stack frame, if they affect
 // it at all. The DWARF format takes advantage of this fact, and
 // reduces the size of the data by mentioning only the addresses and
 // columns at which changes take place. So for the above, DWARF CFI
 // data would only actually mention the following:
 //
 //     insn      cfa    r0      r1 ...  ra
 //     =======================================
 //     func+0:   sp                     cfa[0]
 //     func+1:   sp+16
 //     func+2:          cfa[-4]
 //     func+11:  sp+20
 //     func+21:         r0
 //     func+22:  sp
 //
 // In fact, this is the way the parser reports CFI to the consumer: as
 // a series of statements of the form, "At address X, column Y changed
 // to Z," and related conventions for describing the initial state.
 //
 // Naturally, it would be impractical to have to scan the entire
 // program's CFI, noting changes as we go, just to recover the
 // unwinding rules in effect at one particular instruction. To avoid
 // this, CFI data is grouped into "entries", each of which covers a
 // specified range of addresses and begins with a complete statement
 // of the rules for all recoverable registers at that starting
 // address. Each entry typically covers a single function.
 //
 // Thus, to compute the contents of a given row of the table --- that
 // is, rules for recovering the CFA, RA, and registers at a given
 // instruction --- the consumer should find the entry that covers that
 // instruction's address, start with the initial state supplied at the
 // beginning of the entry, and work forward until it has processed all
 // the changes up to and including those for the present instruction.
 //
 // There are seven kinds of rules that can appear in an entry of the
 // table:
 //
 // - "undefined": The given register is not preserved by the callee;
 //   its value cannot be recovered.
 //
 // - "same value": This register has the same value it did in the callee.
 //
 // - offset(N): The register is saved at offset N from the CFA.
 //
 // - val_offset(N): The value the register had in the caller is the
 //   CFA plus offset N. (This is usually only useful for describing
 //   the stack pointer.)
 //
 // - register(R): The register's value was saved in another register R.
 //
 // - expression(E): Evaluating the DWARF expression E using the
 //   current frame's registers' values yields the address at which the
 //   register was saved.
 //
 // - val_expression(E): Evaluating the DWARF expression E using the
 //   current frame's registers' values yields the value the register
 //   had in the caller.
 class CallFrameInfo {
  public:
   // The different kinds of entries one finds in CFI. Used internally,
   // and for error reporting.
   enum EntryKind { kUnknown, kCIE, kFDE, kTerminator };
   // The handler class to which the parser hands the parsed call frame
   // information.  Defined below.
   class Handler;
   // A reporter class, which CallFrameInfo uses to report errors
   // encountered while parsing call frame information.  Defined below.
   class Reporter;
   // Create a DWARF CFI parser. BUFFER points to the contents of the
   // .debug_frame section to parse; BUFFER_LENGTH is its length in bytes.
   // REPORTER is an error reporter the parser should use to report
   // problems. READER is a ByteReader instance that has the endianness and
   // address size set properly. Report the data we find to HANDLER.
   //
   // This class can also parse Linux C++ exception handling data, as found
   // in '.eh_frame' sections. This data is a variant of DWARF CFI that is
   // placed in loadable segments so that it is present in the program's
   // address space, and is interpreted by the C++ runtime to search the
   // call stack for a handler interested in the exception being thrown,
   // actually pop the frames, and find cleanup code to run.
   //
   // There are two differences between the call frame information described
   // in the DWARF standard and the exception handling data Linux places in
   // the .eh_frame section:
   //
   // - Exception handling data uses uses a different format for call frame
   //   information entry headers. The distinguished CIE id, the way FDEs
   //   refer to their CIEs, and the way the end of the series of entries is
   //   determined are all slightly different.
   //
   //   If the constructor's EH_FRAME argument is true, then the
   //   CallFrameInfo parses the entry headers as Linux C++ exception
   //   handling data. If EH_FRAME is false or omitted, the CallFrameInfo
   //   parses standard DWARF call frame information.
   //
   // - Linux C++ exception handling data uses CIE augmentation strings
   //   beginning with 'z' to specify the presence of additional data after
   //   the CIE and FDE headers and special encodings used for addresses in
   //   frame description entries.
   //
   //   CallFrameInfo can handle 'z' augmentations in either DWARF CFI or
   //   exception handling data if you have supplied READER with the base
   //   addresses needed to interpret the pointer encodings that 'z'
   //   augmentations can specify. See the ByteReader interface for details
   //   about the base addresses. See the CallFrameInfo::Handler interface
   //   for details about the additional information one might find in
   //   'z'-augmented data.
   //
   // Thus:
   //
   // - If you are parsing standard DWARF CFI, as found in a .debug_frame
   //   section, you should pass false for the EH_FRAME argument, or omit
   //   it, and you need not worry about providing READER with the
   //   additional base addresses.
   //
   // - If you want to parse Linux C++ exception handling data from a
   //   .eh_frame section, you should pass EH_FRAME as true, and call
   //   READER's Set*Base member functions before calling our Start method.
   //
   // - If you want to parse DWARF CFI that uses the 'z' augmentations
   //   (although I don't think any toolchain ever emits such data), you
   //   could pass false for EH_FRAME, but call READER's Set*Base members.
   //
   // The extensions the Linux C++ ABI makes to DWARF for exception
   // handling are described here, rather poorly:
   // http://refspecs.linux-foundation.org/LSB_4.0.0/LSB-Core-generic/LSB-Core-generic/dwarfext.html
   // http://refspecs.linux-foundation.org/LSB_4.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html
   //
   // The mechanics of C++ exception handling, personality routines,
   // and language-specific data areas are described here, rather nicely:
   // http://www.codesourcery.com/public/cxx-abi/abi-eh.html
   CallFrameInfo(const char *buffer, size_t buffer_length,
                 ByteReader *reader, Handler *handler, Reporter *reporter,
                 bool eh_frame = false)
       : buffer_(buffer), buffer_length_(buffer_length),
         reader_(reader), handler_(handler), reporter_(reporter),
         eh_frame_(eh_frame) { }
   ~CallFrameInfo() { }
   // Parse the entries in BUFFER, reporting what we find to HANDLER.
   // Return true if we reach the end of the section successfully, or
   // false if we encounter an error.
   bool Start();
   // Return the textual name of KIND. For error reporting.
   static const char *KindName(EntryKind kind);
  private:
   struct CIE;
   // A CFI entry, either an FDE or a CIE.
   struct Entry {
     // The starting offset of the entry in the section, for error
     // reporting.
     size_t offset;
     // The start of this entry in the buffer.
     const char *start;
     // Which kind of entry this is.
     //
     // We want to be able to use this for error reporting even while we're
     // in the midst of parsing. Error reporting code may assume that kind,
     // offset, and start fields are valid, although kind may be kUnknown.
     EntryKind kind;
     // The end of this entry's common prologue (initial length and id), and
     // the start of this entry's kind-specific fields.
     const char *fields;
     // The start of this entry's instructions.
     const char *instructions;
     // The address past the entry's last byte in the buffer. (Note that
     // since offset points to the entry's initial length field, and the
     // length field is the number of bytes after that field, this is not
     // simply buffer_ + offset + length.)
     const char *end;
     // For both DWARF CFI and .eh_frame sections, this is the CIE id in a
     // CIE, and the offset of the associated CIE in an FDE.
     uint64 id;
     // The CIE that applies to this entry, if we've parsed it. If this is a
     // CIE, then this field points to this structure.
     CIE *cie;
   };
   // A common information entry (CIE).
   struct CIE: public Entry {
     uint8 version;                      // CFI data version number
     std::string augmentation;           // vendor format extension markers
     uint64 code_alignment_factor;       // scale for code address adjustments
     int data_alignment_factor;          // scale for stack pointer adjustments
     unsigned return_address_register;   // which register holds the return addr
     // True if this CIE includes Linux C++ ABI 'z' augmentation data.
     bool has_z_augmentation;
     // Parsed 'z' augmentation data. These are meaningful only if
     // has_z_augmentation is true.
     bool has_z_lsda;                    // The 'z' augmentation included 'L'.
     bool has_z_personality;             // The 'z' augmentation included 'P'.
     bool has_z_signal_frame;            // The 'z' augmentation included 'S'.
     // If has_z_lsda is true, this is the encoding to be used for language-
     // specific data area pointers in FDEs.
     DwarfPointerEncoding lsda_encoding;
     // If has_z_personality is true, this is the encoding used for the
     // personality routine pointer in the augmentation data.
     DwarfPointerEncoding personality_encoding;
     // If has_z_personality is true, this is the address of the personality
     // routine --- or, if personality_encoding & DW_EH_PE_indirect, the
     // address where the personality routine's address is stored.
     uint64 personality_address;
     // This is the encoding used for addresses in the FDE header and
     // in DW_CFA_set_loc instructions. This is always valid, whether
     // or not we saw a 'z' augmentation string; its default value is
     // DW_EH_PE_absptr, which is what normal DWARF CFI uses.
     DwarfPointerEncoding pointer_encoding;
   };
   // A frame description entry (FDE).
   struct FDE: public Entry {
     uint64 address;                     // start address of described code
     uint64 size;                        // size of described code, in bytes
     // If cie->has_z_lsda is true, then this is the language-specific data
     // area's address --- or its address's address, if cie->lsda_encoding
     // has the DW_EH_PE_indirect bit set.
     uint64 lsda_address;
   };
   // Internal use.
   class Rule;
   class UndefinedRule;
   class SameValueRule;
   class OffsetRule;
   class ValOffsetRule;
   class RegisterRule;
   class ExpressionRule;
   class ValExpressionRule;
   class RuleMap;
   class State;
   // Parse the initial length and id of a CFI entry, either a CIE, an FDE,
   // or a .eh_frame end-of-data mark. CURSOR points to the beginning of the
   // data to parse. On success, populate ENTRY as appropriate, and return
   // true. On failure, report the problem, and return false. Even if we
   // return false, set ENTRY->end to the first byte after the entry if we
   // were able to figure that out, or NULL if we weren't.
   bool ReadEntryPrologue(const char *cursor, Entry *entry);
   // Parse the fields of a CIE after the entry prologue, including any 'z'
   // augmentation data. Assume that the 'Entry' fields of CIE are
   // populated; use CIE->fields and CIE->end as the start and limit for
   // parsing. On success, populate the rest of *CIE, and return true; on
   // failure, report the problem and return false.
   bool ReadCIEFields(CIE *cie);
   // Parse the fields of an FDE after the entry prologue, including any 'z'
   // augmentation data. Assume that the 'Entry' fields of *FDE are
   // initialized; use FDE->fields and FDE->end as the start and limit for
   // parsing. Assume that FDE->cie is fully initialized. On success,
   // populate the rest of *FDE, and return true; on failure, report the
   // problem and return false.
   bool ReadFDEFields(FDE *fde);
   // Report that ENTRY is incomplete, and return false. This is just a
   // trivial wrapper for invoking reporter_->Incomplete; it provides a
   // little brevity.
   bool ReportIncomplete(Entry *entry);
   // Return true if ENCODING has the DW_EH_PE_indirect bit set.
   static bool IsIndirectEncoding(DwarfPointerEncoding encoding) {
     return encoding & DW_EH_PE_indirect;
   }
   // The contents of the DWARF .debug_info section we're parsing.
   const char *buffer_;
   size_t buffer_length_;
   // For reading multi-byte values with the appropriate endianness.
   ByteReader *reader_;
   // The handler to which we should report the data we find.
   Handler *handler_;
   // For reporting problems in the info we're parsing.
   Reporter *reporter_;
   // True if we are processing .eh_frame-format data.
   bool eh_frame_;
 };
 // The handler class for CallFrameInfo.  The a CFI parser calls the
 // member functions of a handler object to report the data it finds.
 class CallFrameInfo::Handler {
  public:
   // The pseudo-register number for the canonical frame address.
   enum { kCFARegister = DW_REG_CFA };
   Handler() { }
   virtual ~Handler() { }
   // The parser has found CFI for the machine code at ADDRESS,
   // extending for LENGTH bytes. OFFSET is the offset of the frame
   // description entry in the section, for use in error messages.
   // VERSION is the version number of the CFI format. AUGMENTATION is
   // a string describing any producer-specific extensions present in
   // the data. RETURN_ADDRESS is the number of the register that holds
   // the address to which the function should return.
   //
   // Entry should return true to process this CFI, or false to skip to
   // the next entry.
   //
   // The parser invokes Entry for each Frame Description Entry (FDE)
   // it finds.  The parser doesn't report Common Information Entries
   // to the handler explicitly; instead, if the handler elects to
   // process a given FDE, the parser reiterates the appropriate CIE's
   // contents at the beginning of the FDE's rules.
   virtual bool Entry(size_t offset, uint64 address, uint64 length,
                      uint8 version, const std::string &augmentation,
                      unsigned return_address) = 0;
   // When the Entry function returns true, the parser calls these
   // handler functions repeatedly to describe the rules for recovering
   // registers at each instruction in the given range of machine code.
   // Immediately after a call to Entry, the handler should assume that
   // the rule for each callee-saves register is "unchanged" --- that
   // is, that the register still has the value it had in the caller.
   //
   // If a *Rule function returns true, we continue processing this entry's
   // instructions. If a *Rule function returns false, we stop evaluating
   // instructions, and skip to the next entry. Either way, we call End
   // before going on to the next entry.
   //
   // In all of these functions, if the REG parameter is kCFARegister, then
   // the rule describes how to find the canonical frame address.
   // kCFARegister may be passed as a BASE_REGISTER argument, meaning that
   // the canonical frame address should be used as the base address for the
   // computation. All other REG values will be positive.
   // At ADDRESS, register REG's value is not recoverable.
   virtual bool UndefinedRule(uint64 address, int reg) = 0;
   // At ADDRESS, register REG's value is the same as that it had in
   // the caller.
   virtual bool SameValueRule(uint64 address, int reg) = 0;
   // At ADDRESS, register REG has been saved at offset OFFSET from
   // BASE_REGISTER.
   virtual bool OffsetRule(uint64 address, int reg,
                           int base_register, long offset) = 0;
   // At ADDRESS, the caller's value of register REG is the current
   // value of BASE_REGISTER plus OFFSET. (This rule doesn't provide an
   // address at which the register's value is saved.)
   virtual bool ValOffsetRule(uint64 address, int reg,
                              int base_register, long offset) = 0;
   // At ADDRESS, register REG has been saved in BASE_REGISTER. This differs
   // from ValOffsetRule(ADDRESS, REG, BASE_REGISTER, 0), in that
   // BASE_REGISTER is the "home" for REG's saved value: if you want to
   // assign to a variable whose home is REG in the calling frame, you
   // should put the value in BASE_REGISTER.
   virtual bool RegisterRule(uint64 address, int reg, int base_register) = 0;
   // At ADDRESS, the DWARF expression EXPRESSION yields the address at
   // which REG was saved.
   virtual bool ExpressionRule(uint64 address, int reg,
                               const std::string &expression) = 0;
   // At ADDRESS, the DWARF expression EXPRESSION yields the caller's
   // value for REG. (This rule doesn't provide an address at which the
   // register's value is saved.)
   virtual bool ValExpressionRule(uint64 address, int reg,
                                  const std::string &expression) = 0;
   // Indicate that the rules for the address range reported by the
   // last call to Entry are complete.  End should return true if
   // everything is okay, or false if an error has occurred and parsing
   // should stop.
   virtual bool End() = 0;
   // Handler functions for Linux C++ exception handling data. These are
   // only called if the data includes 'z' augmentation strings.
   // The Linux C++ ABI uses an extension of the DWARF CFI format to
   // walk the stack to propagate exceptions from the throw to the
   // appropriate catch, and do the appropriate cleanups along the way.
   // CFI entries used for exception handling have two additional data
   // associated with them:
   //
   // - The "language-specific data area" describes which exception
   //   types the function has 'catch' clauses for, and indicates how
   //   to go about re-entering the function at the appropriate catch
   //   clause. If the exception is not caught, it describes the
   //   destructors that must run before the frame is popped.
   //
   // - The "personality routine" is responsible for interpreting the
   //   language-specific data area's contents, and deciding whether
   //   the exception should continue to propagate down the stack,
   //   perhaps after doing some cleanup for this frame, or whether the
   //   exception will be caught here.
   //
   // In principle, the language-specific data area is opaque to
   // everybody but the personality routine. In practice, these values
   // may be useful or interesting to readers with extra context, and
   // we have to at least skip them anyway, so we might as well report
   // them to the handler.
   // This entry's exception handling personality routine's address is
   // ADDRESS. If INDIRECT is true, then ADDRESS is the address at
   // which the routine's address is stored. The default definition for
   // this handler function simply returns true, allowing parsing of
   // the entry to continue.
   virtual bool PersonalityRoutine(uint64 address, bool indirect) {
     return true;
   }
   // This entry's language-specific data area (LSDA) is located at
   // ADDRESS. If INDIRECT is true, then ADDRESS is the address at
   // which the area's address is stored. The default definition for
   // this handler function simply returns true, allowing parsing of
   // the entry to continue.
   virtual bool LanguageSpecificDataArea(uint64 address, bool indirect) {
     return true;
   }
   // This entry describes a signal trampoline --- this frame is the
   // caller of a signal handler. The default definition for this
   // handler function simply returns true, allowing parsing of the
   // entry to continue.
   //
   // The best description of the rationale for and meaning of signal
   // trampoline CFI entries seems to be in the GCC bug database:
   // http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26208
   virtual bool SignalHandler() { return true; }
 };
 // The CallFrameInfo class makes calls on an instance of this class to
 // report errors or warn about problems in the data it is parsing.
 // These messages are sent to the message sink |aLog| provided to the
 // constructor.
 class CallFrameInfo::Reporter {
  public:
   // Create an error reporter which attributes troubles to the section
   // named SECTION in FILENAME.
   //
   // Normally SECTION would be .debug_frame, but the Mac puts CFI data
   // in a Mach-O section named __debug_frame. If we support
   // Linux-style exception handling data, we could be reading an
   // .eh_frame section.
   Reporter(void (*aLog)(const char*),
            const std::string &filename,
            const std::string &section = ".debug_frame")
       : log_(aLog), filename_(filename), section_(section) { }
   virtual ~Reporter() { }
   // The CFI entry at OFFSET ends too early to be well-formed. KIND
   // indicates what kind of entry it is; KIND can be kUnknown if we
   // haven't parsed enough of the entry to tell yet.
   virtual void Incomplete(uint64 offset, CallFrameInfo::EntryKind kind);
   // The .eh_frame data has a four-byte zero at OFFSET where the next
   // entry's length would be; this is a terminator. However, the buffer
   // length as given to the CallFrameInfo constructor says there should be
   // more data.
   virtual void EarlyEHTerminator(uint64 offset);
   // The FDE at OFFSET refers to the CIE at CIE_OFFSET, but the
   // section is not that large.
   virtual void CIEPointerOutOfRange(uint64 offset, uint64 cie_offset);
   // The FDE at OFFSET refers to the CIE at CIE_OFFSET, but the entry
   // there is not a CIE.
   virtual void BadCIEId(uint64 offset, uint64 cie_offset);
   // The FDE at OFFSET refers to a CIE with version number VERSION,
   // which we don't recognize. We cannot parse DWARF CFI if it uses
   // a version number we don't recognize.
   virtual void UnrecognizedVersion(uint64 offset, int version);
   // The FDE at OFFSET refers to a CIE with augmentation AUGMENTATION,
   // which we don't recognize. We cannot parse DWARF CFI if it uses
   // augmentations we don't recognize.
   virtual void UnrecognizedAugmentation(uint64 offset,
                                         const std::string &augmentation);
   // The pointer encoding ENCODING, specified by the CIE at OFFSET, is not
   // a valid encoding.
   virtual void InvalidPointerEncoding(uint64 offset, uint8 encoding);
   // The pointer encoding ENCODING, specified by the CIE at OFFSET, depends
   // on a base address which has not been supplied.
   virtual void UnusablePointerEncoding(uint64 offset, uint8 encoding);
   // The CIE at OFFSET contains a DW_CFA_restore instruction at
   // INSN_OFFSET, which may not appear in a CIE.
   virtual void RestoreInCIE(uint64 offset, uint64 insn_offset);
   // The entry at OFFSET, of kind KIND, has an unrecognized
   // instruction at INSN_OFFSET.
   virtual void BadInstruction(uint64 offset, CallFrameInfo::EntryKind kind,
                               uint64 insn_offset);
   // The instruction at INSN_OFFSET in the entry at OFFSET, of kind
   // KIND, establishes a rule that cites the CFA, but we have not
   // established a CFA rule yet.
   virtual void NoCFARule(uint64 offset, CallFrameInfo::EntryKind kind,
                          uint64 insn_offset);
   // The instruction at INSN_OFFSET in the entry at OFFSET, of kind
   // KIND, is a DW_CFA_restore_state instruction, but the stack of
   // saved states is empty.
   virtual void EmptyStateStack(uint64 offset, CallFrameInfo::EntryKind kind,
                                uint64 insn_offset);
   // The DW_CFA_remember_state instruction at INSN_OFFSET in the entry
   // at OFFSET, of kind KIND, would restore a state that has no CFA
   // rule, whereas the current state does have a CFA rule. This is
   // bogus input, which the CallFrameInfo::Handler interface doesn't
   // (and shouldn't) have any way to report.
   virtual void ClearingCFARule(uint64 offset, CallFrameInfo::EntryKind kind,
                                uint64 insn_offset);
  private:
   // A logging sink function, as supplied by LUL's user.
   void (*log_)(const char*);
  protected:
   // The name of the file whose CFI we're reading.
   std::string filename_;
   // The name of the CFI section in that file.
   std::string section_;
 };
 using lul::CallFrameInfo;
 using lul::Summariser;
 // A class that accepts parsed call frame information from the DWARF
 // CFI parser and populates a google_breakpad::Module object with the
 // contents.
 class DwarfCFIToModule: public CallFrameInfo::Handler {
  public:
   // DwarfCFIToModule uses an instance of this class to report errors
   // detected while converting DWARF CFI to Breakpad STACK CFI records.
   class Reporter {
    public:
     // Create a reporter that writes messages to the message sink
     // |aLog|. FILE is the name of the file we're processing, and
     // SECTION is the name of the section within that file that we're
     // looking at (.debug_frame, .eh_frame, etc.).
     Reporter(void (*aLog)(const char*),
              const std::string &file, const std::string &section)
       : log_(aLog), file_(file), section_(section) { }
     virtual ~Reporter() { }
     // The DWARF CFI entry at OFFSET says that REG is undefined, but the
     // Breakpad symbol file format cannot express this.
     virtual void UndefinedNotSupported(size_t offset,
                                        const UniqueString* reg);
     // The DWARF CFI entry at OFFSET says that REG uses a DWARF
     // expression to find its value, but DwarfCFIToModule is not
     // capable of translating DWARF expressions to Breakpad postfix
     // expressions.
     virtual void ExpressionsNotSupported(size_t offset,
                                          const UniqueString* reg);
   private:
     // A logging sink function, as supplied by LUL's user.
     void (*log_)(const char*);
   protected:
     std::string file_, section_;
   };
   // Register name tables. If TABLE is a vector returned by one of these
   // functions, then TABLE[R] is the name of the register numbered R in
   // DWARF call frame information.
   class RegisterNames {
    public:
     // Intel's "x86" or IA-32.
     static const unsigned int I386();
     // AMD x86_64, AMD64, Intel EM64T, or Intel 64
     static const unsigned int X86_64();
     // ARM.
     static const unsigned int ARM();
   };
   // Create a handler for the dwarf2reader::CallFrameInfo parser that
   // records the stack unwinding information it receives in SUMM.
   //
   // Use REGISTER_NAMES[I] as the name of register number I; *this
   // keeps a reference to the vector, so the vector should remain
   // alive for as long as the DwarfCFIToModule does.
   //
   // Use REPORTER for reporting problems encountered in the conversion
   // process.
   DwarfCFIToModule(const unsigned int num_dw_regs,
                    Reporter *reporter,
                    /*OUT*/Summariser* summ)
       : summ_(summ), num_dw_regs_(num_dw_regs), reporter_(reporter),
         return_address_(-1) {
   }
   virtual ~DwarfCFIToModule() {}
   virtual bool Entry(size_t offset, uint64 address, uint64 length,
                      uint8 version, const std::string &augmentation,
                      unsigned return_address);
   virtual bool UndefinedRule(uint64 address, int reg);
   virtual bool SameValueRule(uint64 address, int reg);
   virtual bool OffsetRule(uint64 address, int reg,
                           int base_register, long offset);
   virtual bool ValOffsetRule(uint64 address, int reg,
                              int base_register, long offset);
   virtual bool RegisterRule(uint64 address, int reg, int base_register);
   virtual bool ExpressionRule(uint64 address, int reg,
                               const std::string &expression);
   virtual bool ValExpressionRule(uint64 address, int reg,
                                  const std::string &expression);
   virtual bool End();
  private:
   // Return the name to use for register REG.
   const UniqueString* RegisterName(int i);
   // The Summariser to which we should give entries
   Summariser* summ_;
   // The number of Dwarf-defined register names for this architecture.
   const unsigned int num_dw_regs_;
   // The reporter to use to report problems.
   Reporter *reporter_;
   // The section offset of the current frame description entry, for
   // use in error messages.
   size_t entry_offset_;
   // The return address column for that entry.
   unsigned return_address_;
 };
 } // namespace lul
 #endif // LulDwarfExt_h

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tools/profiler/LulDwarfExt.h@97036ab72558 (annotated)

tools/profiler/LulDwarfExt.h