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diff --git a/docs/GettingStarted.rst b/docs/GettingStarted.rst new file mode 100644 index 0000000000..d78c78f1cc --- /dev/null +++ b/docs/GettingStarted.rst @@ -0,0 +1,1304 @@ +.. _getting_started: + +==================================== +Getting Started with the LLVM System +==================================== + +Overview +======== + +Welcome to LLVM! In order to get started, you first need to know some basic +information. + +First, LLVM comes in three pieces. The first piece is the LLVM suite. This +contains all of the tools, libraries, and header files needed to use LLVM. It +contains an assembler, disassembler, bitcode analyzer and bitcode optimizer. It +also contains basic regression tests that can be used to test the LLVM tools and +the Clang front end. + +The second piece is the `Clang <http://clang.llvm.org/>`_ front end. This +component compiles C, C++, Objective C, and Objective C++ code into LLVM +bitcode. Once compiled into LLVM bitcode, a program can be manipulated with the +LLVM tools from the LLVM suite. + +There is a third, optional piece called Test Suite. It is a suite of programs +with a testing harness that can be used to further test LLVM's functionality +and performance. + +Getting Started Quickly (A Summary) +=================================== + +The LLVM Getting Started documentation may be out of date. So, the `Clang +Getting Started <http://clang.llvm.org/get_started.html>`_ page might also be a +good place to start. + +Here's the short story for getting up and running quickly with LLVM: + +#. Read the documentation. +#. Read the documentation. +#. Remember that you were warned twice about reading the documentation. +#. Checkout LLVM: + + * ``cd where-you-want-llvm-to-live`` + * ``svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm`` + +#. Checkout Clang: + + * ``cd where-you-want-llvm-to-live`` + * ``cd llvm/tools`` + * ``svn co http://llvm.org/svn/llvm-project/cfe/trunk clang`` + +#. Checkout Compiler-RT: + + * ``cd where-you-want-llvm-to-live`` + * ``cd llvm/projects`` + * ``svn co http://llvm.org/svn/llvm-project/compiler-rt/trunk compiler-rt`` + +#. Get the Test Suite Source Code **[Optional]** + + * ``cd where-you-want-llvm-to-live`` + * ``cd llvm/projects`` + * ``svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite`` + +#. Configure and build LLVM and Clang: + + * ``cd where-you-want-to-build-llvm`` + * ``mkdir build`` (for building without polluting the source dir) + * ``cd build`` + * ``../llvm/configure [options]`` + Some common options: + + * ``--prefix=directory`` --- + + Specify for *directory* the full pathname of where you want the LLVM + tools and libraries to be installed (default ``/usr/local``). + + * ``--enable-optimized`` --- + + Compile with optimizations enabled (default is NO). + + * ``--enable-assertions`` --- + + Compile with assertion checks enabled (default is YES). + + * ``make [-j]`` --- The ``-j`` specifies the number of jobs (commands) to run + simultaneously. This builds both LLVM and Clang for Debug+Asserts mode. + The --enabled-optimized configure option is used to specify a Release + build. + + * ``make check-all`` --- This run the regression tests to ensure everything + is in working order. + + * ``make update`` --- This command is used to update all the svn repositories + at once, rather then having to ``cd`` into the individual repositories and + running ``svn update``. + + * It is also possible to use CMake instead of the makefiles. With CMake it is + also possible to generate project files for several IDEs: Eclipse CDT4, + CodeBlocks, Qt-Creator (use the CodeBlocks generator), KDevelop3. + + * If you get an "internal compiler error (ICE)" or test failures, see + `below`. + +Consult the `Getting Started with LLVM`_ section for detailed information on +configuring and compiling LLVM. See `Setting Up Your Environment`_ for tips +that simplify working with the Clang front end and LLVM tools. Go to `Program +Layout`_ to learn about the layout of the source code tree. + +Requirements +============ + +Before you begin to use the LLVM system, review the requirements given below. +This may save you some trouble by knowing ahead of time what hardware and +software you will need. + +Hardware +-------- + +LLVM is known to work on the following platforms: + ++-----------------+----------------------+-------------------------+ +|OS | Arch | Compilers | ++=================+======================+=========================+ +|AuroraUX | x86\ :sup:`1` | GCC | ++-----------------+----------------------+-------------------------+ +|Linux | x86\ :sup:`1` | GCC | ++-----------------+----------------------+-------------------------+ +|Linux | amd64 | GCC | ++-----------------+----------------------+-------------------------+ +|Solaris | V9 (Ultrasparc) | GCC | ++-----------------+----------------------+-------------------------+ +|FreeBSD | x86\ :sup:`1` | GCC | ++-----------------+----------------------+-------------------------+ +|FreeBSD | amd64 | GCC | ++-----------------+----------------------+-------------------------+ +|MacOS X\ :sup:`2`| PowerPC | GCC | ++-----------------+----------------------+-------------------------+ +|MacOS X\ :sup:`9`| x86 | GCC | ++-----------------+----------------------+-------------------------+ +|Cygwin/Win32 | x86\ :sup:`1, 8, 11` | GCC 3.4.X, binutils 2.20| ++-----------------+----------------------+-------------------------+ + +LLVM has partial support for the following platforms: + ++-------------------+----------------------+-------------------------------------------+ +|OS | Arch | Compilers | ++===================+======================+===========================================+ +| Windows | x86\ :sup:`1` | Visual Studio 2000 or higher\ :sup:`4,5` | ++-------------------+----------------------+-------------------------------------------+ +| AIX\ :sup:`3,4` | PowerPC | GCC | ++-------------------+----------------------+-------------------------------------------+ +| Linux\ :sup:`3,5` | PowerPC | GCC | ++-------------------+----------------------+-------------------------------------------+ +| Linux\ :sup:`7` | Alpha | GCC | ++-------------------+----------------------+-------------------------------------------+ +| Linux\ :sup:`7` | Itanium (IA-64) | GCC | ++-------------------+----------------------+-------------------------------------------+ +| HP-UX\ :sup:`7` | Itanium (IA-64) | HP aCC | ++-------------------+----------------------+-------------------------------------------+ +| Windows x64 | x86-64 | mingw-w64's GCC-4.5.x\ :sup:`12` | ++-------------------+----------------------+-------------------------------------------+ + +.. note:: + + Code generation supported for Pentium processors and up + + #. Code generation supported for Pentium processors and up + #. Code generation supported for 32-bit ABI only + #. No native code generation + #. Build is not complete: one or more tools do not link or function + #. The GCC-based C/C++ frontend does not build + #. The port is done using the MSYS shell. + #. Native code generation exists but is not complete. + #. Binutils 2.20 or later is required to build the assembler generated by LLVM properly. + #. Xcode 2.5 and gcc 4.0.1 (Apple Build 5370) will trip internal LLVM assert + messages when compiled for Release at optimization levels greater than 0 + (i.e., ``-O1`` and higher). Add ``OPTIMIZE_OPTION="-O0"`` to the build + command line if compiling for LLVM Release or bootstrapping the LLVM + toolchain. + #. For MSYS/MinGW on Windows, be sure to install the MSYS version of the perl + package, and be sure it appears in your path before any Windows-based + versions such as Strawberry Perl and ActivePerl, as these have + Windows-specifics that will cause the build to fail. + #. To use LLVM modules on Win32-based system, you may configure LLVM + with ``--enable-shared``. + + #. To compile SPU backend, you need to add ``LDFLAGS=-Wl,--stack,16777216`` to + configure. + +Note that you will need about 1-3 GB of space for a full LLVM build in Debug +mode, depending on the system (it is so large because of all the debugging +information and the fact that the libraries are statically linked into multiple +tools). If you do not need many of the tools and you are space-conscious, you +can pass ``ONLY_TOOLS="tools you need"`` to make. The Release build requires +considerably less space. + +The LLVM suite *may* compile on other platforms, but it is not guaranteed to do +so. If compilation is successful, the LLVM utilities should be able to +assemble, disassemble, analyze, and optimize LLVM bitcode. Code generation +should work as well, although the generated native code may not work on your +platform. + +Software +-------- + +Compiling LLVM requires that you have several software packages installed. The +table below lists those required packages. The Package column is the usual name +for the software package that LLVM depends on. The Version column provides +"known to work" versions of the package. The Notes column describes how LLVM +uses the package and provides other details. + ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| Package | Version | Notes | ++==============================================================+=================+=============================================+ +| `GNU Make <http://savannah.gnu.org/projects/make>`_ | 3.79, 3.79.1 | Makefile/build processor | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| `GCC <http://gcc.gnu.org/>`_ | 3.4.2 | C/C++ compiler\ :sup:`1` | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| `TeXinfo <http://www.gnu.org/software/texinfo/>`_ | 4.5 | For building the CFE | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| `SVN <http://subversion.tigris.org/project_packages.html>`_ | >=1.3 | Subversion access to LLVM\ :sup:`2` | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| `DejaGnu <http://savannah.gnu.org/projects/dejagnu>`_ | 1.4.2 | Automated test suite\ :sup:`3` | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| `tcl <http://www.tcl.tk/software/tcltk/>`_ | 8.3, 8.4 | Automated test suite\ :sup:`3` | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| `expect <http://expect.nist.gov/>`_ | 5.38.0 | Automated test suite\ :sup:`3` | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| `perl <http://www.perl.com/download.csp>`_ | >=5.6.0 | Utilities | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| `GNU M4 <http://savannah.gnu.org/projects/m4>`_ | 1.4 | Macro processor for configuration\ :sup:`4` | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| `GNU Autoconf <http://www.gnu.org/software/autoconf/>`_ | 2.60 | Configuration script builder\ :sup:`4` | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| `GNU Automake <http://www.gnu.org/software/automake/>`_ | 1.9.6 | aclocal macro generator\ :sup:`4` | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ +| `libtool <http://savannah.gnu.org/projects/libtool>`_ | 1.5.22 | Shared library manager\ :sup:`4` | ++--------------------------------------------------------------+-----------------+---------------------------------------------+ + +.. note:: + + #. Only the C and C++ languages are needed so there's no need to build the + other languages for LLVM's purposes. See `below` for specific version + info. + #. You only need Subversion if you intend to build from the latest LLVM + sources. If you're working from a release distribution, you don't need + Subversion. + #. Only needed if you want to run the automated test suite in the + ``llvm/test`` directory. + #. If you want to make changes to the configure scripts, you will need GNU + autoconf (2.60), and consequently, GNU M4 (version 1.4 or higher). You + will also need automake (1.9.6). We only use aclocal from that package. + +Additionally, your compilation host is expected to have the usual plethora of +Unix utilities. Specifically: + +* **ar** --- archive library builder +* **bzip2** --- bzip2 command for distribution generation +* **bunzip2** --- bunzip2 command for distribution checking +* **chmod** --- change permissions on a file +* **cat** --- output concatenation utility +* **cp** --- copy files +* **date** --- print the current date/time +* **echo** --- print to standard output +* **egrep** --- extended regular expression search utility +* **find** --- find files/dirs in a file system +* **grep** --- regular expression search utility +* **gzip** --- gzip command for distribution generation +* **gunzip** --- gunzip command for distribution checking +* **install** --- install directories/files +* **mkdir** --- create a directory +* **mv** --- move (rename) files +* **ranlib** --- symbol table builder for archive libraries +* **rm** --- remove (delete) files and directories +* **sed** --- stream editor for transforming output +* **sh** --- Bourne shell for make build scripts +* **tar** --- tape archive for distribution generation +* **test** --- test things in file system +* **unzip** --- unzip command for distribution checking +* **zip** --- zip command for distribution generation + +.. _below: +.. _check here: + +Broken versions of GCC and other tools +-------------------------------------- + +LLVM is very demanding of the host C++ compiler, and as such tends to expose +bugs in the compiler. In particular, several versions of GCC crash when trying +to compile LLVM. We routinely use GCC 4.2 (and higher) or Clang. Other +versions of GCC will probably work as well. GCC versions listed here are known +to not work. If you are using one of these versions, please try to upgrade your +GCC to something more recent. If you run into a problem with a version of GCC +not listed here, please `let us know <mailto:llvmdev@cs.uiuc.edu>`_. Please use +the "``gcc -v``" command to find out which version of GCC you are using. + +**GCC versions prior to 3.0**: GCC 2.96.x and before had several problems in the +STL that effectively prevent it from compiling LLVM. + +**GCC 3.2.2 and 3.2.3**: These versions of GCC fails to compile LLVM with a +bogus template error. This was fixed in later GCCs. + +**GCC 3.3.2**: This version of GCC suffered from a `serious bug +<http://gcc.gnu.org/PR13392>`_ which causes it to crash in the +"``convert_from_eh_region_ranges_1``" GCC function. + +**Cygwin GCC 3.3.3**: The version of GCC 3.3.3 commonly shipped with Cygwin does +not work. + +**SuSE GCC 3.3.3**: The version of GCC 3.3.3 shipped with SuSE 9.1 (and possibly +others) does not compile LLVM correctly (it appears that exception handling is +broken in some cases). Please download the FSF 3.3.3 or upgrade to a newer +version of GCC. + +**GCC 3.4.0 on linux/x86 (32-bit)**: GCC miscompiles portions of the code +generator, causing an infinite loop in the llvm-gcc build when built with +optimizations enabled (i.e. a release build). + +**GCC 3.4.2 on linux/x86 (32-bit)**: GCC miscompiles portions of the code +generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0) correctly +compiles LLVM at -O2. A work around is to build release LLVM builds with +"``make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ...``" + +**GCC 3.4.x on X86-64/amd64**: GCC `miscompiles portions of LLVM +<http://llvm.org/PR1056>`__. + +**GCC 3.4.4 (CodeSourcery ARM 2005q3-2)**: this compiler miscompiles LLVM when +building with optimizations enabled. It appears to work with "``make +ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1``" or build a debug build. + +**IA-64 GCC 4.0.0**: The IA-64 version of GCC 4.0.0 is known to miscompile LLVM. + +**Apple Xcode 2.3**: GCC crashes when compiling LLVM at -O3 (which is the +default with ENABLE_OPTIMIZED=1. To work around this, build with +"``ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2``". + +**GCC 4.1.1**: GCC fails to build LLVM with template concept check errors +compiling some files. At the time of this writing, GCC mainline (4.2) did not +share the problem. + +**GCC 4.1.1 on X86-64/amd64**: GCC `miscompiles portions of LLVM +<http://llvm.org/PR1063>`__ when compiling llvm itself into 64-bit code. LLVM +will appear to mostly work but will be buggy, e.g. failing portions of its +testsuite. + +**GCC 4.1.2 on OpenSUSE**: Seg faults during libstdc++ build and on x86_64 +platforms compiling md5.c gets a mangled constant. + +**GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian**: Appears to +miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining about +symbols remaining in the table on destruction. + +**GCC 4.1.2 20071124 (Red Hat 4.1.2-42)**: Suffers from the same symptoms as the +previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default). + +**Cygwin GCC 4.3.2 20080827 (beta) 2**: Users `reported +<http://llvm.org/PR4145>`_ various problems related with link errors when using +this GCC version. + +**Debian GCC 4.3.2 on X86**: Crashes building some files in LLVM 2.6. + +**GCC 4.3.3 (Debian 4.3.3-10) on ARM**: Miscompiles parts of LLVM 2.6 when +optimizations are turned on. The symptom is an infinite loop in +``FoldingSetImpl::RemoveNode`` while running the code generator. + +**SUSE 11 GCC 4.3.4**: Miscompiles LLVM, causing crashes in ValueHandle logic. + +**GCC 4.3.5 and GCC 4.4.5 on ARM**: These can miscompile ``value >> 1`` even at +``-O0``. A test failure in ``test/Assembler/alignstack.ll`` is one symptom of +the problem. + +**GNU ld 2.16.X**. Some 2.16.X versions of the ld linker will produce very long +warning messages complaining that some "``.gnu.linkonce.t.*``" symbol was +defined in a discarded section. You can safely ignore these messages as they are +erroneous and the linkage is correct. These messages disappear using ld 2.17. + +**GNU binutils 2.17**: Binutils 2.17 contains `a bug +<http://sourceware.org/bugzilla/show_bug.cgi?id=3111>`__ which causes huge link +times (minutes instead of seconds) when building LLVM. We recommend upgrading +to a newer version (2.17.50.0.4 or later). + +**GNU Binutils 2.19.1 Gold**: This version of Gold contained `a bug +<http://sourceware.org/bugzilla/show_bug.cgi?id=9836>`__ which causes +intermittent failures when building LLVM with position independent code. The +symptom is an error about cyclic dependencies. We recommend upgrading to a +newer version of Gold. + +.. _Getting Started with LLVM: + +Getting Started with LLVM +========================= + +The remainder of this guide is meant to get you up and running with LLVM and to +give you some basic information about the LLVM environment. + +The later sections of this guide describe the `general layout`_ of the LLVM +source tree, a `simple example`_ using the LLVM tool chain, and `links`_ to find +more information about LLVM or to get help via e-mail. + +Terminology and Notation +------------------------ + +Throughout this manual, the following names are used to denote paths specific to +the local system and working environment. *These are not environment variables +you need to set but just strings used in the rest of this document below*. In +any of the examples below, simply replace each of these names with the +appropriate pathname on your local system. All these paths are absolute: + +``SRC_ROOT`` + + This is the top level directory of the LLVM source tree. + +``OBJ_ROOT`` + + This is the top level directory of the LLVM object tree (i.e. the tree where + object files and compiled programs will be placed. It can be the same as + SRC_ROOT). + +.. _Setting Up Your Environment: + +Setting Up Your Environment +--------------------------- + +In order to compile and use LLVM, you may need to set some environment +variables. + +``LLVM_LIB_SEARCH_PATH=/path/to/your/bitcode/libs`` + + [Optional] This environment variable helps LLVM linking tools find the + locations of your bitcode libraries. It is provided only as a convenience + since you can specify the paths using the -L options of the tools and the + C/C++ front-end will automatically use the bitcode files installed in its + ``lib`` directory. + +Unpacking the LLVM Archives +--------------------------- + +If you have the LLVM distribution, you will need to unpack it before you can +begin to compile it. LLVM is distributed as a set of two files: the LLVM suite +and the LLVM GCC front end compiled for your platform. There is an additional +test suite that is optional. Each file is a TAR archive that is compressed with +the gzip program. + +The files are as follows, with *x.y* marking the version number: + +``llvm-x.y.tar.gz`` + + Source release for the LLVM libraries and tools. + +``llvm-test-x.y.tar.gz`` + + Source release for the LLVM test-suite. + +``llvm-gcc-4.2-x.y.source.tar.gz`` + + Source release of the llvm-gcc-4.2 front end. See README.LLVM in the root + directory for build instructions. + +``llvm-gcc-4.2-x.y-platform.tar.gz`` + + Binary release of the llvm-gcc-4.2 front end for a specific platform. + +Checkout LLVM from Subversion +----------------------------- + +If you have access to our Subversion repository, you can get a fresh copy of the +entire source code. All you need to do is check it out from Subversion as +follows: + +* ``cd where-you-want-llvm-to-live`` +* Read-Only: ``svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm`` +* Read-Write:``svn co https://user@llvm.org/svn/llvm-project/llvm/trunk llvm`` + +This will create an '``llvm``' directory in the current directory and fully +populate it with the LLVM source code, Makefiles, test directories, and local +copies of documentation files. + +If you want to get a specific release (as opposed to the most recent revision), +you can checkout it from the '``tags``' directory (instead of '``trunk``'). The +following releases are located in the following subdirectories of the '``tags``' +directory: + +* Release 3.1: **RELEASE_31/final** +* Release 3.0: **RELEASE_30/final** +* Release 2.9: **RELEASE_29/final** +* Release 2.8: **RELEASE_28** +* Release 2.7: **RELEASE_27** +* Release 2.6: **RELEASE_26** +* Release 2.5: **RELEASE_25** +* Release 2.4: **RELEASE_24** +* Release 2.3: **RELEASE_23** +* Release 2.2: **RELEASE_22** +* Release 2.1: **RELEASE_21** +* Release 2.0: **RELEASE_20** +* Release 1.9: **RELEASE_19** +* Release 1.8: **RELEASE_18** +* Release 1.7: **RELEASE_17** +* Release 1.6: **RELEASE_16** +* Release 1.5: **RELEASE_15** +* Release 1.4: **RELEASE_14** +* Release 1.3: **RELEASE_13** +* Release 1.2: **RELEASE_12** +* Release 1.1: **RELEASE_11** +* Release 1.0: **RELEASE_1** + +If you would like to get the LLVM test suite (a separate package as of 1.4), you +get it from the Subversion repository: + +.. code:: bash + + % cd llvm/projects + % svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite + +By placing it in the ``llvm/projects``, it will be automatically configured by +the LLVM configure script as well as automatically updated when you run ``svn +update``. + +GIT mirror +---------- + +GIT mirrors are available for a number of LLVM subprojects. These mirrors sync +automatically with each Subversion commit and contain all necessary git-svn +marks (so, you can recreate git-svn metadata locally). Note that right now +mirrors reflect only ``trunk`` for each project. You can do the read-only GIT +clone of LLVM via: + +.. code:: bash + + % git clone http://llvm.org/git/llvm.git + +If you want to check out clang too, run: + +.. code:: bash + + % git clone http://llvm.org/git/llvm.git + % cd llvm/tools + % git clone http://llvm.org/git/clang.git + +Since the upstream repository is in Subversion, you should use ``git +pull --rebase`` instead of ``git pull`` to avoid generating a non-linear history +in your clone. To configure ``git pull`` to pass ``--rebase`` by default on the +master branch, run the following command: + +.. code:: bash + + % git config branch.master.rebase true + +Sending patches with Git +^^^^^^^^^^^^^^^^^^^^^^^^ + +Please read `Developer Policy <DeveloperPolicy.html#patches>`_, too. + +Assume ``master`` points the upstream and ``mybranch`` points your working +branch, and ``mybranch`` is rebased onto ``master``. At first you may check +sanity of whitespaces: + +.. code:: bash + + % git diff --check master..mybranch + +The easiest way to generate a patch is as below: + +.. code:: bash + + % git diff master..mybranch > /path/to/mybranch.diff + +It is a little different from svn-generated diff. git-diff-generated diff has +prefixes like ``a/`` and ``b/``. Don't worry, most developers might know it +could be accepted with ``patch -p1 -N``. + +But you may generate patchset with git-format-patch. It generates by-each-commit +patchset. To generate patch files to attach to your article: + +.. code:: bash + + % git format-patch --no-attach master..mybranch -o /path/to/your/patchset + +If you would like to send patches directly, you may use git-send-email or +git-imap-send. Here is an example to generate the patchset in Gmail's [Drafts]. + +.. code:: bash + + % git format-patch --attach master..mybranch --stdout | git imap-send + +Then, your .git/config should have [imap] sections. + +.. code:: bash + + [imap] + host = imaps://imap.gmail.com + user = your.gmail.account@gmail.com + pass = himitsu! + port = 993 + sslverify = false + ; in English + folder = "[Gmail]/Drafts" + ; example for Japanese, "Modified UTF-7" encoded. + folder = "[Gmail]/&Tgtm+DBN-" + ; example for Traditional Chinese + folder = "[Gmail]/&g0l6Pw-" + +For developers to work with git-svn +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +To set up clone from which you can submit code using ``git-svn``, run: + +.. code:: bash + + % git clone http://llvm.org/git/llvm.git + % cd llvm + % git svn init https://llvm.org/svn/llvm-project/llvm/trunk --username=<username> + % git config svn-remote.svn.fetch :refs/remotes/origin/master + % git svn rebase -l # -l avoids fetching ahead of the git mirror. + + # If you have clang too: + % cd tools + % git clone http://llvm.org/git/clang.git + % cd clang + % git svn init https://llvm.org/svn/llvm-project/cfe/trunk --username=<username> + % git config svn-remote.svn.fetch :refs/remotes/origin/master + % git svn rebase -l + +To update this clone without generating git-svn tags that conflict with the +upstream git repo, run: + +.. code:: bash + + % git fetch && (cd tools/clang && git fetch) # Get matching revisions of both trees. + % git checkout master + % git svn rebase -l + % (cd tools/clang && + git checkout master && + git svn rebase -l) + +This leaves your working directories on their master branches, so you'll need to +``checkout`` each working branch individually and ``rebase`` it on top of its +parent branch. (Note: This script is intended for relative newbies to git. If +you have more experience, you can likely improve on it.) + +The git-svn metadata can get out of sync after you mess around with branches and +``dcommit``. When that happens, ``git svn dcommit`` stops working, complaining +about files with uncommitted changes. The fix is to rebuild the metadata: + +.. code:: bash + + % rm -rf .git/svn + % git svn rebase -l + +Local LLVM Configuration +------------------------ + +Once checked out from the Subversion repository, the LLVM suite source code must +be configured via the ``configure`` script. This script sets variables in the +various ``*.in`` files, most notably ``llvm/Makefile.config`` and +``llvm/include/Config/config.h``. It also populates *OBJ_ROOT* with the +Makefiles needed to begin building LLVM. + +The following environment variables are used by the ``configure`` script to +configure the build system: + ++------------+-----------------------------------------------------------+ +| Variable | Purpose | ++============+===========================================================+ +| CC | Tells ``configure`` which C compiler to use. By default, | +| | ``configure`` will look for the first GCC C compiler in | +| | ``PATH``. Use this variable to override ``configure``\'s | +| | default behavior. | ++------------+-----------------------------------------------------------+ +| CXX | Tells ``configure`` which C++ compiler to use. By | +| | default, ``configure`` will look for the first GCC C++ | +| | compiler in ``PATH``. Use this variable to override | +| | ``configure``'s default behavior. | ++------------+-----------------------------------------------------------+ + +The following options can be used to set or enable LLVM specific options: + +``--enable-optimized`` + + Enables optimized compilation (debugging symbols are removed and GCC + optimization flags are enabled). Note that this is the default setting if you + are using the LLVM distribution. The default behavior of an Subversion + checkout is to use an unoptimized build (also known as a debug build). + +``--enable-debug-runtime`` + + Enables debug symbols in the runtime libraries. The default is to strip debug + symbols from the runtime libraries. + +``--enable-jit`` + + Compile the Just In Time (JIT) compiler functionality. This is not available + on all platforms. The default is dependent on platform, so it is best to + explicitly enable it if you want it. + +``--enable-targets=target-option`` + + Controls which targets will be built and linked into llc. The default value + for ``target_options`` is "all" which builds and links all available targets. + The value "host-only" can be specified to build only a native compiler (no + cross-compiler targets available). The "native" target is selected as the + target of the build host. You can also specify a comma separated list of + target names that you want available in llc. The target names use all lower + case. The current set of targets is: + + ``arm, cpp, hexagon, mblaze, mips, mipsel, msp430, powerpc, ptx, sparc, spu, + x86, x86_64, xcore``. + +``--enable-doxygen`` + + Look for the doxygen program and enable construction of doxygen based + documentation from the source code. This is disabled by default because + generating the documentation can take a long time and producess 100s of + megabytes of output. + +``--with-udis86`` + + LLVM can use external disassembler library for various purposes (now it's used + only for examining code produced by JIT). This option will enable usage of + `udis86 <http://udis86.sourceforge.net/>`_ x86 (both 32 and 64 bits) + disassembler library. + +To configure LLVM, follow these steps: + +#. Change directory into the object root directory: + + .. code:: bash + + % cd OBJ_ROOT + +#. Run the ``configure`` script located in the LLVM source tree: + + .. code:: bash + + % SRC_ROOT/configure --prefix=/install/path [other options] + +Compiling the LLVM Suite Source Code +------------------------------------ + +Once you have configured LLVM, you can build it. There are three types of +builds: + +Debug Builds + + These builds are the default when one is using an Subversion checkout and + types ``gmake`` (unless the ``--enable-optimized`` option was used during + configuration). The build system will compile the tools and libraries with + debugging information. To get a Debug Build using the LLVM distribution the + ``--disable-optimized`` option must be passed to ``configure``. + +Release (Optimized) Builds + + These builds are enabled with the ``--enable-optimized`` option to + ``configure`` or by specifying ``ENABLE_OPTIMIZED=1`` on the ``gmake`` command + line. For these builds, the build system will compile the tools and libraries + with GCC optimizations enabled and strip debugging information from the + libraries and executables it generates. Note that Release Builds are default + when using an LLVM distribution. + +Profile Builds + + These builds are for use with profiling. They compile profiling information + into the code for use with programs like ``gprof``. Profile builds must be + started by specifying ``ENABLE_PROFILING=1`` on the ``gmake`` command line. + +Once you have LLVM configured, you can build it by entering the *OBJ_ROOT* +directory and issuing the following command: + +.. code:: bash + + % gmake + +If the build fails, please `check here`_ to see if you are using a version of +GCC that is known not to compile LLVM. + +If you have multiple processors in your machine, you may wish to use some of the +parallel build options provided by GNU Make. For example, you could use the +command: + +.. code:: bash + + % gmake -j2 + +There are several special targets which are useful when working with the LLVM +source code: + +``gmake clean`` + + Removes all files generated by the build. This includes object files, + generated C/C++ files, libraries, and executables. + +``gmake dist-clean`` + + Removes everything that ``gmake clean`` does, but also removes files generated + by ``configure``. It attempts to return the source tree to the original state + in which it was shipped. + +``gmake install`` + + Installs LLVM header files, libraries, tools, and documentation in a hierarchy + under ``$PREFIX``, specified with ``./configure --prefix=[dir]``, which + defaults to ``/usr/local``. + +``gmake -C runtime install-bytecode`` + + Assuming you built LLVM into $OBJDIR, when this command is run, it will + install bitcode libraries into the GCC front end's bitcode library directory. + If you need to update your bitcode libraries, this is the target to use once + you've built them. + +Please see the `Makefile Guide <MakefileGuide.html>`_ for further details on +these ``make`` targets and descriptions of other targets available. + +It is also possible to override default values from ``configure`` by declaring +variables on the command line. The following are some examples: + +``gmake ENABLE_OPTIMIZED=1`` + + Perform a Release (Optimized) build. + +``gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1`` + + Perform a Release (Optimized) build without assertions enabled. + +``gmake ENABLE_OPTIMIZED=0`` + + Perform a Debug build. + +``gmake ENABLE_PROFILING=1`` + + Perform a Profiling build. + +``gmake VERBOSE=1`` + + Print what ``gmake`` is doing on standard output. + +``gmake TOOL_VERBOSE=1`` + + Ask each tool invoked by the makefiles to print out what it is doing on + the standard output. This also implies ``VERBOSE=1``. + +Every directory in the LLVM object tree includes a ``Makefile`` to build it and +any subdirectories that it contains. Entering any directory inside the LLVM +object tree and typing ``gmake`` should rebuild anything in or below that +directory that is out of date. + +Cross-Compiling LLVM +-------------------- + +It is possible to cross-compile LLVM itself. That is, you can create LLVM +executables and libraries to be hosted on a platform different from the platform +where they are build (a Canadian Cross build). To configure a cross-compile, +supply the configure script with ``--build`` and ``--host`` options that are +different. The values of these options must be legal target triples that your +GCC compiler supports. + +The result of such a build is executables that are not runnable on on the build +host (--build option) but can be executed on the compile host (--host option). + +The Location of LLVM Object Files +--------------------------------- + +The LLVM build system is capable of sharing a single LLVM source tree among +several LLVM builds. Hence, it is possible to build LLVM for several different +platforms or configurations using the same source tree. + +This is accomplished in the typical autoconf manner: + +* Change directory to where the LLVM object files should live: + + .. code:: bash + + % cd OBJ_ROOT + +* Run the ``configure`` script found in the LLVM source directory: + + .. code:: bash + + % SRC_ROOT/configure + +The LLVM build will place files underneath *OBJ_ROOT* in directories named after +the build type: + +Debug Builds with assertions enabled (the default) + + Tools + + ``OBJ_ROOT/Debug+Asserts/bin`` + + Libraries + + ``OBJ_ROOT/Debug+Asserts/lib`` + +Release Builds + + Tools + + ``OBJ_ROOT/Release/bin`` + + Libraries + + ``OBJ_ROOT/Release/lib`` + +Profile Builds + + Tools + + ``OBJ_ROOT/Profile/bin`` + + Libraries + + ``OBJ_ROOT/Profile/lib`` + +Optional Configuration Items +---------------------------- + +If you're running on a Linux system that supports the `binfmt_misc +<http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html>`_ +module, and you have root access on the system, you can set your system up to +execute LLVM bitcode files directly. To do this, use commands like this (the +first command may not be required if you are already using the module): + +.. code:: bash + + % mount -t binfmt_misc none /proc/sys/fs/binfmt_misc + % echo ':llvm:M::BC::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register + % chmod u+x hello.bc (if needed) + % ./hello.bc + +This al |