4.6. Binutils-2.42¶

The Binutils package contains a linker, an assembler, and other tools for handling object files.

4.6.1. Installation of Cross Binutils¶

It is important that Binutils be the first package compiled because both the C library and GCC perform various tests on the available linker and assembler to determine which of their own features to enable.

The Binutils documentation recommends building Binutils outside of the source directory in a dedicated build directory:

mkdir -v ../binutils-build
cd ../binutils-build

Prepare Binutils for compilation:

../binutils-2.42/configure \
  --prefix=${CLFS}/cross-tools \
  --target=${CLFS_TARGET} \
  --with-sysroot=${CLFS}/cross-tools/${CLFS_TARGET} \
  --disable-nls \
  --enable-gprofng=no \
  --disable-multilib

The meaning of the configure options:

--prefix=${CLFS}/cross-tools: This tells the configure script to prepare to install the package in the ${CLFS}/cross-tools directory.
--target=${CLFS_TARGET}: This creates a cross-architecture executable that creates files for ${CLFS_TARGET} but runs on the host system.
--with-sysroot=${CLFS}/cross-tools/${CLFS_TARGET}: This tells configure that ${CLFS} is going to be the root of our system. It will now use the specified sysroot, ${CLFS}, as a prefix of the default search paths.
--disable-nls: This disables internationalization as i18n is not needed for the cross-compile tools.
--disable-multilib: This option disables the building of a multilib capable binutils.

Compile the package:

make configure-host
make

The meaning of the make options:

configure-host: This checks the host environment and makes sure all the necessary tools are available to compile Binutils.

Install the package:

make install

4.6.2. Contents of Binutils¶

Installed programs: addr2line, ar, as, c++filt, elfedit, gprof, ld, nm, objcopy, objdump, ranlib, readelf, size, strings, and strip

Installed libraries: libiberty.a, libbfd.[a,so], and libopcodes.[a,so]

Short Descriptions¶

addr2line: Translates program addresses to file names and line numbers; given an address and the name of an executable, it uses the debugging information in the executable to determine which source file and line number are associated with the address

ar: Creates, modifies, and extracts from archives

as: An assembler that assembles the output of gcc into object files

c++filt: Used by the linker to de-mangle C++ and Java symbols and to keep overloaded functions from clashing

elfedit: Examine and modify ELF metadata within an ELF object

gprof: Displays call graph profile data

ld: A linker that combines a number of object and archive files into a single file, relocating their data and tying up symbol references

nm: Lists the symbols occurring in a given object file

objcopy: Copy the contents of one object file to another

objdump: Displays information about the given object file, with options controlling the particular information to display; the information shown is useful to programmers who are working on the compilation tools

ranlib: Generates an index of the contents of an archive and stores it in the archive; the index lists all of the symbols defined by archive members that are relocatable object files

readelf: Displays information about ELF type binaries

size: Lists the section sizes and the total size for the given object files

strings: Outputs, for each given file, the sequences of printable characters that are of at least the specified length (defaulting to four); for object files, it prints, by default, only the strings from the initializing and loading sections while for other types of files, it scans the entire file

strip: Discards symbols from object files
libiberty: Contains routines used by various GNU programs, including getopt, obstack, strerror, strtol, and strtoul
libbfd: The Binary File Descriptor library
libopcodes: A library for dealing with opcodes—the “readable text” versions of instructions for the processor; it is used for building utilities like objdump.