gold is an ELF linker. It is intended to have complete support for ELF and to run as fast as possible on modern systems. For normal use it is a drop-in replacement for the older GNU linker. gold is part of the GNU binutils. See ../binutils/README for more general notes, including where to send bug reports. gold was originally developed at Google, and was contributed to the Free Software Foundation in March 2008. At Google it was designed by Ian Lance Taylor, with major contributions by Cary Coutant, Craig Silverstein, and Andrew Chatham. The existing GNU linker manual is intended to be accurate documentation for features which gold supports. gold supports most of the features of the GNU linker for ELF targets. Notable omissions--features of the GNU linker not currently supported in gold--are: * MRI compatible linker scripts * cross-reference reports (--cref) * various other minor options Notes on the code ================= These are some notes which may be helpful to people working on the source code of gold itself. gold is written in C++. It is a GNU program, and therefore follows the GNU formatting standards as modified for C++. Source documents in order of decreasing precedence: http://www.gnu.org/prep/standards/ http://gcc.gnu.org/onlinedocs/libstdc++/manual/source_code_style.html http://www.zembu.com/eng/procs/c++style.html The linker is intended to have complete support for cross-compilation, while still supporting the normal case of native linking as fast as possible. In order to do this, many classes are actually templates whose parameter is the ELF file class (e.g., 32 bits or 64 bits). The C++ code is the same, but we don't pay the execution time cost of always using 64-bit integers if the target is 32 bits. Many of these class templates also have an endianness parameter: true for big-endian, false for little-endian. The linker is multi-threaded. The Task class represents a single unit of work. Task objects are stored on a single Workqueue object. Tasks communicate via Task_token objects. Task_token objects are only manipulated while holding the master Workqueue lock. Relatively few mutexes are used. Build requirements ================== The gold source code uses templates heavily. Building it requires a recent version of g++. g++ 4.0.3 and 4.1.3 are known to work. g++ 3.2, 3.4.3, and 4.1.2 are known to fail. The linker script parser uses features which are only in newer versions of bison. bison 2.3 is known to work. bison 1.26 is known to fail. If you are building gold from an official binutils release, the bison output should already be included. Copyright (C) 2012-2014 Free Software Foundation, Inc. Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.