-.. _getting_started:
-
====================================
Getting Started with the LLVM System
====================================
+.. contents::
+ :local:
+
Overview
========
* ``../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``).
+ * ``--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`` ---
+ * ``--enable-optimized`` --- Compile with optimizations enabled (default
+ is NO).
- Compile with optimizations enabled (default is NO).
-
- * ``--enable-assertions`` ---
-
- Compile with assertion checks enabled (default is YES).
+ * ``--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
+ The ``--enable-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``.
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` |
-+-------------------+----------------------+-------------------------------------------+
+LLVM is known to work on the following host platforms:
+
+================== ===================== =============
+OS Arch Compilers
+================== ===================== =============
+AuroraUX x86\ :sup:`1` GCC
+Linux x86\ :sup:`1` GCC, Clang
+Linux amd64 GCC, Clang
+Linux ARM\ :sup:`4` GCC, Clang
+Linux PowerPC GCC, Clang
+Solaris V9 (Ultrasparc) GCC
+FreeBSD x86\ :sup:`1` GCC, Clang
+FreeBSD amd64 GCC, Clang
+MacOS X\ :sup:`2` PowerPC GCC
+MacOS X x86 GCC, Clang
+Cygwin/Win32 x86\ :sup:`1, 3` GCC
+Windows x86\ :sup:`1` Visual Studio
+Windows x64 x86-64 Visual Studio
+================== ===================== =============
.. 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.
+ #. MCJIT not working well pre-v7, old JIT engine not supported any more.
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
+--------------------------------------------------------------+-----------------+---------------------------------------------+
| `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 |
+| `python <http://www.python.org/>`_ | >=2.5 | Automated test suite\ :sup:`3` |
+--------------------------------------------------------------+-----------------+---------------------------------------------+
| `GNU M4 <http://savannah.gnu.org/projects/m4>`_ | 1.4 | Macro processor for configuration\ :sup:`4` |
+--------------------------------------------------------------+-----------------+---------------------------------------------+
+--------------------------------------------------------------+-----------------+---------------------------------------------+
| `libtool <http://savannah.gnu.org/projects/libtool>`_ | 1.5.22 | Shared library manager\ :sup:`4` |
+--------------------------------------------------------------+-----------------+---------------------------------------------+
+| `zlib <http://zlib.net>`_ | >=1.2.3.4 | Compression library\ :sup:`5` |
++--------------------------------------------------------------+-----------------+---------------------------------------------+
.. note::
#. 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.
+ #. Optional, adds compression/uncompression capabilities to selected LLVM
+ tools.
Additionally, your compilation host is expected to have the usual plethora of
Unix utilities. Specifically:
``-O0``. A test failure in ``test/Assembler/alignstack.ll`` is one symptom of
the problem.
+**GCC 4.6.3 on ARM**: Miscompiles ``llvm-readobj`` at ``-O3``. A test failure
+in ``test/Object/readobj-shared-object.test`` 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
symptom is an error about cyclic dependencies. We recommend upgrading to a
newer version of Gold.
+**Clang 3.0 with libstdc++ 4.7.x**: a few Linux distributions (Ubuntu 12.10,
+Fedora 17) have both Clang 3.0 and libstdc++ 4.7 in their repositories. Clang
+3.0 does not implement a few builtins that are used in this library. We
+recommend using the system GCC to compile LLVM and Clang in this case.
+
+**Clang 3.0 on Mageia 2**. There's a packaging issue: Clang can not find at
+least some (``cxxabi.h``) libstdc++ headers.
+
+**Clang in C++11 mode and libstdc++ 4.7.2**. This version of libstdc++
+contained `a bug <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53841>`__ which
+causes Clang to refuse to compile condition_variable header file. At the time
+of writing, this breaks LLD build.
+
.. _Getting Started with LLVM:
Getting Started with LLVM
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:
Checkout LLVM from Subversion
-----------------------------
following releases are located in the following subdirectories of the '``tags``'
directory:
+* Release 3.3: **RELEASE_33/final**
+* Release 3.2: **RELEASE_32/final**
* Release 3.1: **RELEASE_31/final**
* Release 3.0: **RELEASE_30/final**
* Release 2.9: **RELEASE_29/final**
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-block:: bash
+.. code-block:: console
% cd llvm/projects
% svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite
the LLVM configure script as well as automatically updated when you run ``svn
update``.
-GIT mirror
+Git Mirror
----------
-GIT mirrors are available for a number of LLVM subprojects. These mirrors sync
+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
+mirrors reflect only ``trunk`` for each project. You can do the read-only Git
clone of LLVM via:
-.. code-block:: bash
+.. code-block:: console
% git clone http://llvm.org/git/llvm.git
If you want to check out clang too, run:
-.. code-block:: bash
+.. code-block:: console
- % git clone http://llvm.org/git/llvm.git
% cd llvm/tools
% git clone http://llvm.org/git/clang.git
+If you want to check out compiler-rt too, run:
+
+.. code-block:: console
+
+ % cd llvm/projects
+ % git clone http://llvm.org/git/compiler-rt.git
+
+If you want to check out the Test Suite Source Code (optional), run:
+
+.. code-block:: console
+
+ % cd llvm/projects
+ % git clone http://llvm.org/git/test-suite.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-block:: bash
+.. code-block:: console
% git config branch.master.rebase true
branch, and ``mybranch`` is rebased onto ``master``. At first you may check
sanity of whitespaces:
-.. code-block:: bash
+.. code-block:: console
% git diff --check master..mybranch
The easiest way to generate a patch is as below:
-.. code-block:: bash
+.. code-block:: console
% git diff master..mybranch > /path/to/mybranch.diff
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-block:: bash
+.. code-block:: console
% 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-block:: bash
+.. code-block:: console
% git format-patch --attach master..mybranch --stdout | git imap-send
To set up clone from which you can submit code using ``git-svn``, run:
-.. code-block:: bash
+.. code-block:: console
% git clone http://llvm.org/git/llvm.git
% cd llvm
% git config svn-remote.svn.fetch :refs/remotes/origin/master
% git svn rebase -l
+Likewise for compiler-rt and test-suite.
+
To update this clone without generating git-svn tags that conflict with the
-upstream git repo, run:
+upstream Git repo, run:
-.. code-block:: bash
+.. code-block:: console
% git fetch && (cd tools/clang && git fetch) # Get matching revisions of both trees.
% git checkout master
git checkout master &&
git svn rebase -l)
+Likewise for compiler-rt and test-suite.
+
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.)
+parent branch.
+
+For those who wish to be able to update an llvm repo/revert patches easily using
+git-svn, please look in the directory for the scripts ``git-svnup`` and
+``git-svnrevert``.
+
+To perform the aforementioned update steps go into your source directory and
+just type ``git-svnup`` or ``git svnup`` and everything will just work.
+
+If one wishes to revert a commit with git-svn, but do not want the git hash to
+escape into the commit message, one can use the script ``git-svnrevert`` or
+``git svnrevert`` which will take in the git hash for the commit you want to
+revert, look up the appropriate svn revision, and output a message where all
+references to the git hash have been replaced with the svn revision.
+
+To commit back changes via git-svn, use ``git svn dcommit``:
+
+.. code-block:: console
+
+ % git svn dcommit
+
+Note that git-svn will create one SVN commit for each Git commit you have pending,
+so squash and edit each commit before executing ``dcommit`` to make sure they all
+conform to the coding standards and the developers' policy.
+
+On success, ``dcommit`` will rebase against the HEAD of SVN, so to avoid conflict,
+please make sure your current branch is up-to-date (via fetch/rebase) before
+proceeding.
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-block:: bash
+.. code-block:: console
% rm -rf .git/svn
% git svn rebase -l
+Please, refer to the Git-SVN manual (``man git-svn``) for more information.
+
Local LLVM Configuration
------------------------
| 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. |
+| | ``configure`` will check ``PATH`` for ``clang`` and GCC C |
+| | compilers (in this order). 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. |
+| | default, ``configure`` will check ``PATH`` for |
+| | ``clang++`` and GCC C++ compilers (in this order). Use |
+| | this variable to override ``configure``'s default |
+| | behavior. |
+------------+-----------------------------------------------------------+
The following options can be used to set or enable LLVM specific options:
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``.
+ ``arm, cpp, hexagon, mips, mipsel, msp430, powerpc, ptx, sparc, spu,
+ systemz, x86, x86_64, xcore``.
``--enable-doxygen``
#. Change directory into the object root directory:
- .. code-block:: bash
+ .. code-block:: console
% cd OBJ_ROOT
#. Run the ``configure`` script located in the LLVM source tree:
- .. code-block:: bash
+ .. code-block:: console
% SRC_ROOT/configure --prefix=/install/path [other options]
Once you have LLVM configured, you can build it by entering the *OBJ_ROOT*
directory and issuing the following command:
-.. code-block:: bash
+.. code-block:: console
% gmake
parallel build options provided by GNU Make. For example, you could use the
command:
-.. code-block:: bash
+.. code-block:: console
% gmake -j2
After following the instructions there for installing Sphinx, build the LLVM
HTML documentation by doing the following:
-.. code-block:: bash
+.. code-block:: console
$ cd SRC_ROOT/docs
$ make -f Makefile.sphinx
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).
+Check :doc:`HowToCrossCompileLLVM` and `Clang docs on how to cross-compile in general
+<http://clang.llvm.org/docs/CrossCompilation.html>`_ for more information
+about cross-compiling.
+
The Location of LLVM Object Files
---------------------------------
* Change directory to where the LLVM object files should live:
- .. code-block:: bash
+ .. code-block:: console
% cd OBJ_ROOT
* Run the ``configure`` script found in the LLVM source directory:
- .. code-block:: bash
+ .. code-block:: console
% SRC_ROOT/configure
----------------------------
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>`_
+<http://en.wikipedia.org/wiki/binfmt_misc>`_
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-block:: bash
+.. code-block:: console
% mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
% echo ':llvm:M::BC::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
This allows you to execute LLVM bitcode files directly. On Debian, you can also
use this command instead of the 'echo' command above:
-.. code-block:: bash
+.. code-block:: console
% sudo update-binfmts --install llvm /path/to/lli --magic 'BC'
This directory holds the source code for the LLVM assembly language parser
library.
-``llvm/lib/BitCode/``
+``llvm/lib/Bitcode/``
This directory holds code for reading and write LLVM bitcode.
#. Next, compile the C file into a native executable:
- .. code-block:: bash
+ .. code-block:: console
% clang hello.c -o hello
Clang works just like GCC by default. The standard -S and -c arguments
work as usual (producing a native .s or .o file, respectively).
-#. Next, compile the C file into a LLVM bitcode file:
+#. Next, compile the C file into an LLVM bitcode file:
- .. code-block:: bash
+ .. code-block:: console
% clang -O3 -emit-llvm hello.c -c -o hello.bc
#. Run the program in both forms. To run the program, use:
- .. code-block:: bash
+ .. code-block:: console
% ./hello
and
- .. code-block:: bash
+ .. code-block:: console
% lli hello.bc
#. Use the ``llvm-dis`` utility to take a look at the LLVM assembly code:
- .. code-block:: bash
+ .. code-block:: console
% llvm-dis < hello.bc | less
#. Compile the program to native assembly using the LLC code generator:
- .. code-block:: bash
+ .. code-block:: console
% llc hello.bc -o hello.s
#. Assemble the native assembly language file into a program:
- .. code-block:: bash
+ .. code-block:: console
- **Solaris:** % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
+ % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native # On Solaris
- **Others:** % gcc hello.s -o hello.native
+ % gcc hello.s -o hello.native # On others
#. Execute the native code program:
- .. code-block:: bash
+ .. code-block:: console
% ./hello.native
projects / oota-llvm.git / blobdiff