First, LLVM comes in two pieces. The first piece is the LLVM suite. This contains all of the tools, libraries, and header files needed to use the low level virtual machine. It contains an assembler, disassembler, bytecode -analyzer, and bytecode optimizer. It also contains a test suite that can be +analyzer and bytecode optimizer. It also contains a test suite that can be used to test the LLVM tools and the GCC front end.
The second piece is the GCC front end. This component provides a version of GCC that compiles C and C++ code into LLVM bytecode. Currently, the GCC front -end is a modified version of GCC 3.4 (we track the GCC 3.4 development). Once +end uses the GCC parser to convert code to LLVM. Once compiled into LLVM bytecode, a program can be manipulated with the LLVM tools from the LLVM suite.
++There is a third, optional piece called llvm-test. It is a suite of programs +with a testing harness that can be used to further test LLVM's functionality +and performance. +
+ @@ -97,45 +112,56 @@ from the LLVM suite.Here's the short story for getting up and running quickly with LLVM:
Specify for directory the full pathname of where you + want the LLVM tools and libraries to be installed (default + /usr/local).
Specify the full pathname of where the LLVM GCC frontend is - installed.
Optionally, specify for directory the full pathname of the + C/C++ front end installation to use with this LLVM configuration. If + not specified, the PATH will be searched.
Enable the SPEC2000 benchmarks for testing. The SPEC2000 benchmarks should be available in @@ -145,10 +171,10 @@ from the LLVM suite.
LLVM is known to work on the following platforms:
-| OS | +Arch | +Compilers | +
|---|---|---|
| Linux | +x861 | +GCC | +
| Solaris | +V9 (Ultrasparc) | +GCC | +
| FreeBSD | +x861 | +GCC | +
| MacOS X2 | +PowerPC | +GCC | +
| MacOS X2 | +x86 | +GCC | + +
| Cygwin/Win32 | +x861,8 | +GCC 3.4.X, binutils 2.15 | +
| MinGW/Win32 | +x861,6,8 | +GCC 3.4.X, binutils 2.15 | +
| Linux | +amd643 | +GCC | +
LLVM has partial support for the following platforms:
+ +| OS | +Arch | +Compilers | +
|---|---|---|
| Windows | +x861 | +Visual Studio .NET4,5 | +
| AIX3,4 | +PowerPC | +GCC | +
| Linux3,5 | +PowerPC | +GCC | +
| Linux7 | +Alpha | +GCC | +
| Linux7 | +Itanium (IA-64) | +GCC | +
| HP-UX7 | +Itanium (IA-64) | +HP aCC | +
Notes:
-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 disable them individually in llvm/tools/Makefile. 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 @@ -240,64 +338,155 @@ generation should work as well, although the generated native code may not work on your platform.
The GCC front end is not very portable at the moment. If you want to get it -to work on another platform, you can download a copy of the source and try to compile it on your platform.
+to work on another platform, you can download a copy of the source and try to compile it on your platform. -Compiling LLVM requires that you have several software packages -installed:
- -There are some additional tools that you may want to have when working with -LLVM:
- -If you want to make changes to the configure scripts, you will need GNU - autoconf (2.57 or higher), and consequently, GNU M4 (version 1.4 or - higher). You will also need automake. Any old version of - automake from 1.4p5 on should work; we only use aclocal from that - package.
- These are needed to use the LLVM test suite. Please note that newer - versions of QMTest may not work with the LLVM test suite. QMTest 2.0.3 - can be retrieved from the QMTest CVS repository using the following - commands:
-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 | +3.79, 3.79.1 | +Makefile/build processor | +
| GCC | +3.4.2 | +C/C++ compiler1 | +
| TeXinfo | +4.5 | +For building the CFE | +
| Flex | +2.5.4 | +LEX compiler | +
| Bison | +1.28, 1.35, 1.75, 1.875d, 2.0, or 2.1 (not 1.85 or 1.875) |
+ YACC compiler | +
| CVS | +≥1.11 | +CVS access to LLVM2 | +
| DejaGnu | +1.4.2 | +Automated test suite3 | +
| tcl | +8.3, 8.4 | +Automated test suite3 | +
| expect | +5.38.0 | +Automated test suite3 | +
| perl | +≥5.6.0 | +Nightly tester, utilities | +
| GNU M4 + | 1.4 | +Macro processor for configuration4 | +
| GNU Autoconf | +2.59 | +Configuration script builder4 | +
| GNU Automake | +1.9.2 | +aclocal macro generator4 | +
| libtool | +1.5.10 | +Shared library manager4 | +
Notes:
+Additionally, your compilation host is expected to have the usual + plethora of Unix utilities. Specifically:
+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 3.3.3 and GCC 3.4.0 and have had success -with them. Other versions of GCC will probably work as well. GCC versions listed +to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1 +successfully with them (however, see below). 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 @@ -322,10 +512,40 @@ of GCC you are using. problems in the STL that effectively prevent it from compiling LLVM.
+GCC 3.2.2: This version of GCC fails to compile LLVM.
+GCC 3.3.2: This version of GCC suffered from a serious bug 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. Please upgrade + to a newer version if possible.
+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.x on X86-64/amd64: GCC + miscompiles portions of LLVM.
+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 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.
+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.
@@ -366,21 +586,21 @@ All these paths are absolute:
+
+
For the pre-built GCC front end binaries, the LLVMGCCDIR is - cfrontend/platform/llvm-gcc. + llvm-gcc/platform/llvm-gcc. @@ -393,23 +613,17 @@ All these paths are absolute:
-In order to compile and use LLVM, you will need to set some environment -variables. There are also some shell aliases which you may find useful. -You can set these on the command line, or better yet, set them in your -.cshrc or .profile. +In order to compile and use LLVM, you may need to set some environment +variables.
- -
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. Each -file is a TAR archive that is compressed with the gzip program. +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: +
The files are as follows, with x.y marking the version number:
+
+
+
+
It is also possible to download the sources of the llvm-gcc4 front end from a +read-only subversion mirror at +svn://anonsvn.opensource.apple.com/svn/llvm/trunk.
+ @@ -465,9 +679,9 @@ follows:If you want to get a specific release (as opposed to the most recent revision), you can specify a label. The following releases have the following -label:
+labels:If you would like to get the GCC front end source code, you can also get it -from the CVS repository:
- +If you would like to get the LLVM test suite (a separate package as of 1.4), +you get it from the CVS repository:
- cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-gcc + cd llvm/projects + cvs -z3 -d :pserver:anon@llvm.org:/var/cvs/llvm co llvm-test+
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 cvs update.
-Please note that you must follow these -instructions to successfully build the LLVM C front-end.
+If you would like to get the GCC front end source code, you can also get it +and build it yourself. Please follow these +instructions to successfully get and build the LLVM GCC front-end.
- -If the main CVS server is overloaded or inaccessible, you can try one of -these user-hosted mirrors:
- - -Before configuring and compiling the LLVM suite, you need to extract the LLVM -GCC front end from the binary distribution. It is used for building the -bytecode libraries later used by the GCC front end for linking programs, and its -location must be specified when the LLVM suite is configured.
+Before configuring and compiling the LLVM suite, you can optionally extract the +LLVM GCC front end from the binary distribution. It is used for running the +llvm-test testsuite and for compiling C/C++ programs. Note that you can optionally +build llvm-gcc yourself after building the +main LLVM repository.
To install the GCC front end, do the following:
If you are using Solaris/Sparc or MacOS X/PPC, you will need to fix the -header files:
- -cd cfrontend/platform
- ./fixheaders
Once the binary is uncompressed, you should add a symlink for llvm-gcc and +llvm-g++ to some directory in your path. When you configure LLVM, it will +automatically detect llvm-gcc's presence (if it is in your path) enabling its +use in llvm-test. Note that you can always build or install llvm-gcc at any +pointer after building the main LLVM repository: just reconfigure llvm and +llvm-test will pick it up. +
The binary versions of the GCC front end may not suit all of your needs. For example, the binary distribution may include an old version of a system header @@ -546,7 +758,7 @@ linked with libraries not available on your system.
In cases like these, you may want to try building the GCC front end from source. This is -not for the faint of heart, so be forewarned.
+much easier now than it was in the past.Once checked out from the CVS repository, the LLVM suite source code must be -configured via the configure script. This script sets variables in -llvm/Makefile.config and llvm/include/Config/config.h. It -also populates OBJ_ROOT with the Makefiles needed to begin building -LLVM.
+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 | -
|---|
| Variable | Purpose |
|---|---|
| CC | Tells configure which C compiler to use. By default, @@ -579,7 +787,6 @@ script to configure the build system: PATH. Use this variable to override configure's default behavior. |
| CXX | Tells configure which C++ compiler to use. By default,
@@ -592,47 +799,69 @@ script to configure the build system:
The following options can be used to set or enable LLVM specific options:
To configure LLVM, follow these steps: @@ -641,24 +870,14 @@ script to configure the build system:cd OBJ_ROOT -
+ - SRC_ROOT/configure -
+ SRC_ROOT/configure --prefix=/install/path [other options]
+ In addition to running configure, you must set the -LLVM_LIB_SEARCH_PATH environment variable in your startup scripts. -This environment variable is used to locate "system" libraries like -"-lc" and "-lm" when linking. This variable should be set to -the absolute path of the bytecode-libs subdirectory of the GCC front -end, or LLVMGCCDIR/bytecode-libs. For example, one might set -LLVM_LIB_SEARCH_PATH to -/home/vadve/lattner/local/x86/llvm-gcc/bytecode-libs for the x86 -version of the GCC front end on our research machines. - @@ -678,7 +897,7 @@ builds: --enable-optimized option was used during configuration). The build system will compile the tools and libraries with debugging information. -
+
+ gmake If the build fails, please check here to see if you -are using a known broken version of GCC to compile LLVM with. +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 @@ -720,25 +939,36 @@ source code:
+
+ 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.
+
+ Installs LLVM header files, libraries, tools, and documentation in a
+ hierarchy
+ under $PREFIX, specified with ./configure --prefix=[dir], which
+ defaults to /usr/local.
+ + Please see the Makefile Guide 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: @@ -746,17 +976,27 @@ declaring variables on the command line. The following are some examples:
+
+
+ Every directory in the LLVM object tree includes a Makefile to build @@ -766,6 +1006,51 @@ that directory that is out of date. + + + +
+
+
It is possible to cross-compile LLVM. That is, you can create LLVM + executables and libraries for a platform different than the one one which you + are compiling. To do this, a few additional steps are + required. 1 To cross-compile LLVM, use + these instructions: +
The result of such a build will produce executables that are not executable + on your build host (--build option) but can be executed on your compile host + (--host option). +Notes: +
+
+
The Location of LLVM Object Files
@@ -798,29 +1083,29 @@ named after the build type:
+
+
-If you're running on a linux system that supports the "binfmt_misc" +If you're running on a Linux system that supports the " + binfmt_misc" module, and you have root access on the system, you can set your system up to execute LLVM bytecode files directly. To do this, use commands like this (the first command may not be required if you are already using the module): +
$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
- $ echo ':llvm:M::llvm::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
+ $ echo ':llvm:M::llvm::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
$ chmod u+x hello.bc (if needed)
$ ./hello.bc
+This allows you to execute LLVM bytecode files directly. Thanks to Jack @@ -865,58 +1153,55 @@ Cummings for pointing this out! One useful source of information about the LLVM source base is the LLVM doxygen documentation available at http://llvm.cs.uiuc.edu/doxygen/. +href="http://llvm.org/doxygen/">http://llvm.org/doxygen/. The following is a brief introduction to code layout:
- CVS directories
-
-
+
-
-Every directory checked out of CVS will contain a CVS directory; for the most part these can just be ignored. -
- llvm/include
+
+
+
+
+
This directory contains some simple examples of how to use the LLVM IR and + JIT. This directory contains public header files exported from the LLVM library. The three main subdirectories of this directory are: -
- llvm/lib
-
-
+
This directory contains most of the source files of the LLVM system. In LLVM, @@ -924,49 +1209,70 @@ almost all code exists in libraries, making it very easy to share code among the different tools.
- llvm/runtime
+
+
+
+
+
This directory contains projects that are not strictly part of LLVM but are + shipped with LLVM. This is also the directory where you should create your own + LLVM-based projects. See llvm/projects/sample for an example of how + to set up your own project. See llvm/projects/Stacker for a fully + functional example of a compiler front end. This directory contains libraries which are compiled into LLVM bytecode and @@ -980,112 +1286,116 @@ end to compile.
- llvm/test
-
-
+
-
-
-This directory contains regression tests and source code that is used to test -the LLVM infrastructure. - +This directory contains feature and regression tests and other basic sanity + checks on the LLVM infrastructure. These are intended to run quickly and cover + a lot of territory without being exhaustive.
- llvm/tools
+
+
+
+
+
This is not a directory in the normal llvm module; it is a separate CVS + module that must be checked out (usually to projects/llvm-test). This + module contains a comprehensive correctness, performance, and benchmarking + test + suite for LLVM. It is a separate CVS module because not every LLVM user is + interested in downloading or building such a comprehensive test suite. For + further details on this test suite, please see the + Testing Guide document. The tools directory contains the executables built out of the libraries above, which form the main part of the user interface. You can always get help for a tool by typing tool_name --help. The -following is a brief introduction to the most important tools: +following is a brief introduction to the most important tools. More detailed +information is in the Command Guide.
- llvm/utils
-
-
+
This directory contains utilities for working with LLVM source code, and some @@ -1093,16 +1403,11 @@ of the utilities are actually required as part of the build process because they are code generators for parts of LLVM infrastructure.
+
+This directory contains build scripts and project files for use with + Visual C++. This allows developers on Windows to build LLVM without the need + for Cygwin. The contents of this directory should be considered experimental + at this time. + +
+
+
+
+
+
This section gives an example of using LLVM. llvm-gcc3 is now obsolete, +so we only include instructiosn for llvm-gcc4. + + +Note: The gcc4 frontend's invocation is considerably different +from the previous gcc3 frontend. In particular, the gcc4 frontend does not +create bytecode by default: gcc4 produces native code. As the example below illustrates, +the '--emit-llvm' flag is needed to produce LLVM bytecode output. For makefiles and +configure scripts, the CFLAGS variable needs '--emit-llvm' to produce bytecode +output. +
Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments. + -% lli hello.bc + +The second examples shows how to invoke the LLVM JIT, lli. % llvm-dis < hello.bc | less % ./hello.native + +Note that using llvm-gcc to compile directly to native code (i.e. when + the -emit-llvm option is not present) does steps 6/7/8 for you. +
Common Problems
@@ -1247,9 +1595,9 @@ if you want to write something up!). For more information about LLVM, check
out:
- The LLVM Compiler Infrastructure + Reid Spencer + The LLVM Compiler Infrastructure Last modified: $Date$ - |