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Diffstat (limited to 'toolkit/crashreporter/google-breakpad/src/common/dwarf/bytereader.h')
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1 files changed, 0 insertions, 315 deletions
diff --git a/toolkit/crashreporter/google-breakpad/src/common/dwarf/bytereader.h b/toolkit/crashreporter/google-breakpad/src/common/dwarf/bytereader.h deleted file mode 100644 index 59d430348..000000000 --- a/toolkit/crashreporter/google-breakpad/src/common/dwarf/bytereader.h +++ /dev/null @@ -1,315 +0,0 @@ -// -*- mode: C++ -*- - -// 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. - -#ifndef COMMON_DWARF_BYTEREADER_H__ -#define COMMON_DWARF_BYTEREADER_H__ - -#include <stdint.h> - -#include <string> - -#include "common/dwarf/types.h" -#include "common/dwarf/dwarf2enums.h" - -namespace dwarf2reader { - -// 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 uint8_t *buffer) const; - - // Read two bytes from BUFFER and return them as an unsigned 16 bit - // number, using this ByteReader's endianness. - uint16 ReadTwoBytes(const uint8_t *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 uint8_t *buffer) const; - - // Read eight bytes from BUFFER and return them as an unsigned 64 - // bit number, using this ByteReader's endianness. - uint64 ReadEightBytes(const uint8_t *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 uint8_t *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 uint8_t *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 uint8_t *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 uint8_t *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 uint8_t *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 uint8_t *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 uint8_t *buffer, - DwarfPointerEncoding encoding, - size_t *len) const; - - Endianness GetEndianness() const; - private: - - // Function pointer type for our address and offset readers. - typedef uint64 (ByteReader::*AddressReader)(const uint8_t *) 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_, text_base_, data_base_, function_base_; - const uint8_t *buffer_base_; -}; - -} // namespace dwarf2reader - -#endif // COMMON_DWARF_BYTEREADER_H__ |