From 3ffb556c58ba69b4f52ae50fa92424300bd58bd1 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Fri, 26 Oct 2012 20:14:19 -0400 Subject: update documentation --- INSTALL | 65 +++++++++++++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 49 insertions(+), 16 deletions(-) (limited to 'INSTALL') diff --git a/INSTALL b/INSTALL index 5c923ee5..017900df 100644 --- a/INSTALL +++ b/INSTALL @@ -5,35 +5,68 @@ musl may be installed either as an alternate C library alongside the existing libraries on a system, or as the primary C library for a new or existing musl-based system. -First, some prerequisites: +This document covers the prerequisites and procedures for compiling +and installation. -- A C99 compiler with gcc-style inline assembly support, support for - weak aliases, and support for building stand-alone assembly files. - gcc 3.x and 4.x are known to work. pcc and LLVM/clang may work but - are untested, and pcc is known to have some bugs. -- GNU make -- Linux, preferably 2.6.22 or later. Older versions are known to have - serious bugs that will make some interfaces non-conformant, but if - you don't need threads or POSIX 2008 features, even 2.4 is probably - okay. +==== Build Prerequisites ==== -- A supported CPU architecture (currently i386, x86_64, arm, or mips). +The only build-time prerequisites for musl are GNU Make and a +freestanding C99 compiler toolchain targeting the desired instruction +set architecture and ABI, with support for gcc-style inline assembly, +weak aliases, and stand-alone assembly source files. -- If you want to use dynamic linking, it's recommended that you have - permissions to write to /lib and /etc. Otherwise your binaries will - have to use a nonstandard dynamic linker path. +The system used to build musl does not need to be Linux-based, nor do +the Linux kernel headers need to be available. +If support for dynamic linking is desired, some further requriements +are placed on the compiler and linker. In particular, the linker must +support the -Bsymbolic-functions option. +At present, GCC 4.6 or later is the recommended compiler for building +musl. Any earlier version of GCC with full C99 support should also +work, but may be subject to minor floating point conformance issues on +i386 targets. Sufficiently recent versions of PCC and LLVM/clang are +also believed to work, but have not been tested as heavily; prior to +Fall 2012, both had known bugs that affected musl. -== Option 1: Installing musl as an alternate C library == + + +=== Supported Targets ==== + +musl can be built for the following CPU instruction set architecture +and ABI combinations: + +- i386 (requires 387 math and 486 cmpxchg instructions) +- x86_64 +- arm (EABI) +- mips (o32 ABI, requires fpu or float emulation in kernel) +- microblaze (requires a cpu with lwx/swx instructions) + +For architectures with both little- and big-endian options, both are +supported unless otherwise noted. + +In general, musl assumes the availability of all Linux syscall +interfaces available in Linux 2.6.0. Some programs that do not use +threads or other modern functionality may be able to run on 2.4.x +kernels. Other kernels (such as BSD) that provide a Linux-compatible +syscall ABI should also work but have not been extensively tested. + + + +==== Option 1: Installing musl as an alternate C library ==== In this setup, musl and any third-party libraries linked to musl will reside under an alternate prefix such as /usr/local/musl or /opt/musl. A wrapper script for gcc, called musl-gcc, can be used in place of gcc to compile and link programs and libraries against musl. +(Note: There are not yet corresponding wrapper scripts for other +compilers, so if you wish to compile and link against musl using +another compiler, you are responsible for providing the correct +options to override the default include and library search paths.) + To install musl as an alternate libc, follow these steps: 1. Configure musl's build with a command similar to: @@ -92,7 +125,7 @@ source/build tree. -== Option 2: Installing musl as the primary C library == +==== Option 2: Installing musl as the primary C library ==== In this setup, you will need an existing compiler/toolchain. It shouldnt matter whether it was configured for glibc, uClibc, musl, or -- cgit v1.2.1