This file documents the port of Mercury to Mac OS X, i.e. the "*-apple-darwin*" configuration. -------- Contents -------- * Mercury on Mac OS X 10.5 to 10.9 * Note for users of Xcode 5 * Note for users of Xcode 4 * Mercury on Mac OS X 10.4 and 10.3 * Mercury on older versions of Mac OS X * Deployment Target Settings * PowerPC Linking Problems * Known bugs and unsupported features * Deep profiling on Mac OS X -------------------------------- Mercury on Mac OS X 10.5 to 10.9 -------------------------------- Mercury should build and install "out-of-the-box" on Intel Mac OS X systems from version 10.5 or later. For information about installing Mercury on versions of Mac OS X before 10.5, including on PowerPC systems, see the sections below. The 'asm_fast*' and 'reg*' grades are only available on 64-bit Intel Mac OS X systems and only when using GCC version 4.3 or later as the C compiler. (This has only been tested with the MacPorts builds of GCC however.) If clang is being used as the C compiler then the only low-level C grades available are the 'none*' grades. The high-level C, Java, Erlang and C# grades all work. The 'erlang' grade requires an Erlang installation to be available and the C# grades require the Mono .NET implementation. (See README.Erlang and README.CSharp for further details.) If the 'asm_fast.gc' grade is not available and unless otherwise directed, the 'hlc.gc' grade will be used as the default grade for compiling applications. By default, 64-bit versions of the executables and libraries in the Mercury system will be installed on x86-64 machines running Mac OS X 10.6 or later. To build a 32-bit installation on such a machine, you need to arrange to have the option "-m32" passed to clang or gcc. This can be done by invoking Mercury's configure script with the option: --with-cc="clang -m32" or: --with-cc="gcc -m32" By default, 32-bit versions of the executables and libraries are installed on x86-64 machines running Mac OS X 10.5. To build and install 64-bit Mercury on such a system you must pass the "-m64" option to the C compiler. Mercury cannot be compiled with llvm-gcc on Mac OS X. If, after installing Mercury, you encounter errors about missing .mih files, and you have fink installed, then try removing the fink components from your PATH (these usually start with /sw) and reinstalling. ------------------------- Note for users of Xcode 5 ------------------------- With Xcode 5.* the executable named "gcc" is actually just a synonym for clang. Mercury's configure script is aware of this and it should not cause any problems. If you wish to use actual GCC instead of clang you will need to install GCC (see the following section for further information). ------------------------- Note for users of Xcode 4 ------------------------- The default C compiler provided with Xcode 4.* is llvm-gcc. Mercury does NOT work with llvm-gcc. Note that with Xcode 4.* the executable named "gcc" is actually a symbolic link for llvm-gcc. In order to build Mercury you will need to use a C compiler other than llvm-gcc, for example clang (See README.clang for further details) or actual GCC. From version 4.2 Xcode no longer includes actual GCC, so if you wish to use that you will need to install it yourself. Mac OS X packages for GCC are provided by: * The MacPorts project * Homebrew * The Fink project As llvm-gcc is no longer supported as of version 3.0 of LLVM, we have no intention of ever supporting Mercury with it. --------------------------------- Mercury on Mac OS X 10.3 and 10.4 --------------------------------- Mercury should work on Mac OS X 10.3 (PowerPC) and 10.4 (both PowerPC and Intel), although it has not been tested with either of these for some time. Apple gcc 2.95 does not work with Mercury because it cannot handle the length of some of the identifier names that the Mercury compiler generates. Apple gcc 3.3 works with Mercury and there are no known issues (other than the problem with gcc's powerpc backend described below). We recommend that users of Mac OS X 10.3 and 10.4 use this version. Apple gcc 4.0 does not work with Mercury. Users of Mac OS X 10.4 should note that this version of gcc is the default one on their systems. On 10.3 and 10.4, if you are using an Apple build of gcc then you must use the gcc_select command to set the system's default gcc to that version of gcc. It is not sufficient to just point Mercury to a version of gcc using the configure script's `--with-cc' option. This restriction applies only to the builds of gcc supplied by Apple. Mainline gcc 3.3.X and 3.4.X are known to work with Mercury on 10.3. Mainline gcc 4.0.X does not. ------------------------------------- Mercury on older versions of Mac OS X ------------------------------------- There may be problems with building Mercury on versions of Mac OS X less than 10.3. In particular, building shared libraries with Mercury on these systems is not supported. The version of tar in /usr/bin/tar on some older versions of Mac OS X (e.g. 10.1) doesn't work properly -- it truncates long path names. Make sure you use GNU tar, which is available in /sw/bin/gtar, when unpacking the Mercury source or binary distributions. (Also, make sure to use GNU tar if/when *building* such distributions!) The version of tar that comes with Mac OS X 10.3.3 does not have this problem. Also, Apple's version of gcc includes support for precompiled headers. Unfortunately this support seems to be somewhat buggy, causing it to sometimes crash with mysterious errors when building Mercury. Furthermore, for the kinds of C code that the Mercury compiler generates, it results in a very big slow-down, rather than any speedup. Fortunately this can be disabled by using the `--traditional-cpp' option. The Mercury configure script should enable this option automatically if it is needed. -------------------------- Deployment Target Settings -------------------------- By default, the Mercury compiler is configured so that the Mac OS X deployment target (i.e. the value of the MACOSX_DEPLOYMENT_TARGET environment variable) for code generated by the Mercury compiler is set to the same version as that of the host system. You can specify a different deployment target at configuration time using the configure script's `--with-macosx-deployment-target' option. (See the ``SDK Compatibility Guide'' in the Apple developer documentation for further information about the deployment target setting.) ------------------------ PowerPC Linking Problems ------------------------ On PowerPC machines, the linker may have problems linking large executables (particularly in debug grades; technically when the program requires a branch larger than +/- 32 MB). It complains about relocation displacements being too large. The only known workaround for this problem is to replace the system-provided versions of crt1.o (Darwin module 'Csu') and crt2.o (part of gcc) with versions that are compiled with the gcc options `-mlongcall' and (if using gcc < ~ 3.4) `-mlong-branch'. C code generated by the Mercury compiler will also need to be compiled with the above options. This can be achieved by adding: EXTRA_CFLAGS=-mlongcall -mlong-branch to your Mercury.options or Mmakefile. ----------------------------------- Known bugs and unsupported features ----------------------------------- The 'asm_fast' grades will not work on *-apple-darwin machines, primarily because of a (long-standing) bug in gcc (GCC bug #10901). By default, the configure script will choose either 'reg' or 'none' as the default base grade. If you do not intend to use debugging (e.g. with production code), then you will probably get better performance by using the hlc.gc grade. Executables created by the Mercury compiler cannot be statically linked against the system libraries, on Mac OS X. Setting `MLFLAGS=-static' or invoking mmc with the `--linkage static' option will result in an error message like the following from the linker: ld: can't locate file for: -lcrt0.o The reason that this does not work is that static version of the system libraries are not installed on OS X systems by default. (See Technical Q&A QA118 for further details.) This restriction only applies to system libraries. Statically linking against Mercury libraries is fine. -------------------------- Deep profiling on Mac OS X -------------------------- The following discussion assumes a standard installation of Mac OS X. By default Apache should have been installed as the default webserver. In order to use the deep profiler you need to ensure that the deep profiling CGI "script" is installed and that the webserver is running. The deep profiling CGI script, mdprof_cgi, should be installed in the directory /Library/WebServer/CGI-Executables. Mercury's normal installation process should take care of this if deep profiling is enabled. To ensure the webserver is running: - Open the Apple Menu and open the System Preferences window. - In the `System Preferences' window, click on the icon labelled `Sharing'. - Make sure that `Personal Web Sharing' is enabled. If it is then the webserver should be running. The remaining instructions for using the deep profiler are the same as those found in the ``Mercury User's Guide''. We recommend against using Safari 1.5 as it has been found to be somewhat unstable with the deep profiler. Later versions of Safari are fine.