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.

@@ -562,14 +622,13 @@ href="#layout">general layout of the 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 @@ -602,22 +661,22 @@ All these paths are absolute:

-
+
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/bytecode/libs
+
LLVM_LIB_SEARCH_PATH=/path/to/your/bitcode/libs

[Optional] This environment variable helps LLVM linking tools find the - locations of your bytecode libraries. It is provided only as a + 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 bytecode files + tools and the C/C++ front-end will automatically use the bitcode files installed in its lib directory.

@@ -625,11 +684,11 @@ variables.
-
+
Unpacking the LLVM Archives -
+ -
+

If you have the LLVM distribution, you will need to unpack it before you @@ -642,54 +701,61 @@ 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.
+
Source release for the LLVM libraries and tools.

llvm-test-x.y.tar.gz
-
Source release for the LLVM test suite.
+
Source release for the LLVM test-suite.
-
llvm-gcc4-x.y.source.tar.gz
-
Source release of the llvm-gcc4 front end. See README.LLVM in the root - directory for build instructions.
+
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-gcc4-x.y-platform.tar.gz
-
Binary release of the llvm-gcc4 front end for a specific platform.
+
llvm-gcc-4.2-x.y-platform.tar.gz
+
Binary release of the llvm-gcc-4.2 front end for a specific platform.

-
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.
-
-
- Checkout LLVM from CVS -
+
+ Checkout LLVM from Subversion +
-
+
-
If you have access to our CVS repository, you can get a fresh copy of -the entire source code. All you need to do is check it out from CVS as +
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 -
cvs -d :pserver:anon@llvm.org:/var/cvs/llvm login -
Hit the return key when prompted for the password. -
cvs -z3 -d :pserver:anon@llvm.org:/var/cvs/llvm co - llvm +
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 specify a label. The following releases have the following -labels:
+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 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
@@ -703,74 +769,265 @@ labels:

If you would like to get the LLVM test suite (a separate package as of 1.4), -you get it from the CVS repository:
+you get it from the Subversion repository:
+ +

- cd llvm/projects - cvs -z3 -d :pserver:anon@llvm.org:/var/cvs/llvm co llvm-test +% 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 cvs update.
+you run svn update.
-
If you would like to get the GCC 3.4 front end source code, you can also get it from the CVS repository:
+
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.
-
- cvs -z3 -d :pserver:anon@llvm.org:/var/cvs/llvm co llvm-gcc +
+ + +
+ 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:
+ +
+git clone http://llvm.org/git/llvm.git +
+ +
If you want to check out clang too, run:
+ +
+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: +
+ +
+git config branch.master.rebase true +
+ +
Sending patches with Git
+
+
+Please read Developer Policy, 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: +
+ +
+git diff --check master..mybranch +
+ +
+The easiest way to generate a patch is as below: +
+ +
+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: +
+ +
+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]. +
+ +
+git format-patch --attach master..mybranch --stdout | git imap-send +
+ +
+Then, your .git/config should have [imap] sections. +
+ +
+[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:
+ +
+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:
+ +
+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)
-
Please note that you must follow these -instructions to successfully build the LLVM GCC front-end.
+
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:
+ +
+rm -rf .git/svn +git svn rebase -l +
+ +

-
+
Install the GCC Front End -
+ -
+
-
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 +
Before configuring and compiling the LLVM suite (or if you want to use just the LLVM +GCC front end) you can optionally extract the front end from the binary distribution. +It is used for running the LLVM test-suite 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:
+
To install the GCC front end, do the following (on Windows, use an archival tool +like 7-zip that understands gzipped tars):

cd where-you-want-the-front-end-to-live
-
gunzip --stdout llvmgcc-version.platform.tar.gz | tar -xvf +
gunzip --stdout llvm-gcc-4.2-version-platform.tar.gz | tar -xvf -
-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. + Once the binary is uncompressed, if you're using a *nix-based system, add a symlink for +llvm-gcc and llvm-g++ to some directory in your path. If you're using a +Windows-based system, add the bin subdirectory of your front end installation directory +to your PATH environment variable. For example, if you uncompressed the binary to +c:\llvm-gcc, add c:\llvm-gcc\bin to your PATH. + +If you now want to build LLVM from source, when you configure LLVM, it will +automatically detect llvm-gcc's presence (if it is in your path) enabling its +use in test-suite. Note that you can always build or install llvm-gcc at any +point after building the main LLVM repository: just reconfigure llvm and +test-suite 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 -file, not "fix" a header file that needs to be fixed for GCC, or it may be -linked with libraries not available on your system. +As a convenience for Windows users, the front end binaries for MinGW/x86 include +versions of the required w32api and mingw-runtime binaries. The last remaining step for +Windows users is to simply uncompress the binary binutils package from +MinGW into your front end installation directory. While the +front end installation steps are not quite the same as a typical manual MinGW installation, +they should be similar enough to those who have previously installed MinGW on Windows systems. -In cases like these, you may want to try building the GCC front end from source. This is -much easier now than it was in the past. +To install binutils on Windows: + + + download GNU Binutils from MinGW Downloads + cd where-you-uncompressed-the-front-end + uncompress archived binutils directories (not the tar file) into the current directory + + +The binary versions of the LLVM GCC front end may not suit all of your needs. For +example, the binary distribution may include an old version of a system header +file, not "fix" a header file that needs to be fixed for GCC, or it may be linked with +libraries not available on your system. In cases like these, you may want to try +building the GCC front end from source. Thankfully, +this is much easier now than it was in the past. + +We also do not currently support updating of the GCC front end by manually overlaying +newer versions of the w32api and mingw-runtime binary packages that may become available +from MinGW. At this time, it's best to think of the MinGW LLVM GCC front end binary as +a self-contained convenience package that requires Windows users to simply download and +uncompress the GNU Binutils binary package from the MinGW project. + +Regardless of your platform, if you discover that installing the LLVM GCC front end +binaries is not as easy as previously described, or you would like to suggest improvements, +please let us know how you would like to see things improved by dropping us a note on our +mailing list.
- + Local LLVM Configuration - + - + -Once checked out from the CVS repository, the LLVM suite source code must be + 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 @@ -812,7 +1069,7 @@ script to configure the build system: will fail as these libraries require llvm-gcc and llvm-g++. See Install the GCC Front End for details on installing the C/C++ Front End. See - Bootstrapping the LLVM C/C++ Front-End + Bootstrapping the LLVM C/C++ Front-End for details on building the C/C++ Front End. --with-tclinclude Path to the tcl include directory under which tclsh can be @@ -825,9 +1082,11 @@ script to configure the build system: --enable-optimized - Enables optimized compilation by default (debugging symbols are removed - and GCC optimization flags are enabled). The default is to use an - unoptimized build (also known as a debug build). + 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 @@ -850,7 +1109,7 @@ script to configure the build system: 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: + names use all lower case. The current set of targets is: alpha, ia64, powerpc, skeleton, sparc, x86. --enable-doxygen @@ -868,25 +1127,26 @@ script to configure the build system: To configure LLVM, follow these steps: - Change directory into the object root directory: - - cd OBJ_ROOT - + Change directory into the object root directory: - Run the configure script located in the LLVM source tree: - - SRC_ROOT/configure --prefix=/install/path [other options] - + % cd OBJ_ROOT + + Run the configure script located in the LLVM source + tree: + + + % 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: @@ -894,10 +1154,12 @@ builds: Debug Builds - These builds are the default when one types gmake (unless the - --enable-optimized option was used during configuration). The - build system will compile the tools and libraries with debugging - information. + 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 @@ -907,6 +1169,7 @@ builds: 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 @@ -920,7 +1183,7 @@ builds: Once you have LLVM configured, you can build it by entering the OBJ_ROOT directory and issuing the following command: -gmake +% 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. @@ -930,7 +1193,7 @@ 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: -gmake -j2 +% gmake -j2 There are several special targets which are useful when working with the LLVM source code: @@ -960,8 +1223,8 @@ source code: gmake -C runtime install-bytecode Assuming you built LLVM into $OBJDIR, when this command is run, it will - install bytecode libraries into the GCC front end's bytecode library - directory. If you need to update your bytecode libraries, + 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. @@ -983,6 +1246,11 @@ declaring variables on the command line. The following are some examples: Perform a Release (Optimized) build without assertions enabled. + + gmake ENABLE_OPTIMIZED=0 + + Perform a Debug build. + gmake ENABLE_PROFILING=1 @@ -1008,56 +1276,29 @@ that directory that is out of date. - + Cross-Compiling LLVM - - - - 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: - - Configure and build LLVM as a native compiler. You will need - just TableGen from that build. - - If you have $LLVM_OBJ_ROOT=$LLVM_SRC_ROOT just execute - make -C utils/TableGen after configuring. - Otherwise you will need to monitor building process and terminate - it just after TableGen was built. - - - Copy the TableGen binary to somewhere safe (out of your build tree). - - Configure LLVM to build with a cross-compiler. To do this, 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. - Put the saved TableGen executable into the - into $LLVM_OBJ_ROOT/{BUILD_TYPE}/bin directory (e.g. into - .../Release/bin for a Release build). - Build LLVM as usual. - - 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 + + + + 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). - Notes: - - - Cross-compiling was tested only with Linux as - build platform and Windows as host using mingw32 cross-compiler. Other - combinations have not been tested. - - - + 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 @@ -1068,25 +1309,25 @@ platforms or configurations using the same source tree. Change directory to where the LLVM object files should live: - cd OBJ_ROOT + % cd OBJ_ROOT Run the configure script found in the LLVM source directory: - SRC_ROOT/configure + % SRC_ROOT/configure The LLVM build will place files underneath OBJ_ROOT in directories named after the build type: - Debug Builds + Debug Builds with assertions enabled (the default) Tools - OBJ_ROOT/Debug/bin + OBJ_ROOT/Debug+Asserts/bin Libraries - OBJ_ROOT/Debug/lib + OBJ_ROOT/Debug+Asserts/lib @@ -1113,69 +1354,72 @@ named after the build type: - + Optional Configuration Items - + - + If you're running on a Linux system that supports the " - binfmt_misc" +href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">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 +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): - $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc - $ echo ':llvm:M::llvm::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register - $ chmod u+x hello.bc (if needed) - $ ./hello.bc +$ 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 allows you to execute LLVM bytecode files directly. Thanks to Jack -Cummings for pointing this out! +This allows you to execute LLVM bitcode files directly. On Debian, you +can also use this command instead of the 'echo' command above: + ++$ sudo update-binfmts --install llvm /path/to/lli --magic 'BC' + + - - - Program Layout + + + + Program Layout + - + One useful source of information about the LLVM source base is the LLVM doxygen documentation available at doxygen documentation available at 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/examples + - -llvm/examples - + This directory contains some simple examples of how to use the LLVM IR and JIT. -llvm/include - + + llvm/include + + + This directory contains public header files exported from the LLVM library. The three main subdirectories of this directory are: @@ -1202,8 +1446,11 @@ library. The three main subdirectories of this directory are: -llvm/lib - + + llvm/lib + + + This directory contains most of the source files of the LLVM system. In LLVM, almost all code exists in libraries, making it very easy to share code among the @@ -1218,8 +1465,8 @@ different tools. This directory holds the source code for the LLVM assembly language parser library. - llvm/lib/ByteCode/ - This directory holds code for reading and write LLVM bytecode. + llvm/lib/BitCode/ + This directory holds code for reading and write LLVM bitcode. llvm/lib/Analysis/ This directory contains a variety of different program analyses, such as Dominator Information, Call Graphs, @@ -1242,41 +1489,47 @@ different tools. This directory contains the major parts of the code generator: Instruction Selector, Instruction Scheduling, and Register Allocation. + llvm/lib/MC/ + (FIXME: T.B.D.) + + llvm/lib/Debugger/ This directory contains the source level debugger library that makes it possible to instrument LLVM programs so that a debugger could identify source code locations at which the program is executing. llvm/lib/ExecutionEngine/ - This directory contains libraries for executing LLVM bytecode directly + This directory contains libraries for executing LLVM bitcode directly at runtime in both interpreted and JIT compiled fashions. llvm/lib/Support/ - This directory contains the source code that corresponds to the header - files located in llvm/include/Support/. - - llvm/lib/System/ - This directory contains the operating system abstraction layer that - shields LLVM from platform-specific coding. + This directory contains the source code that corresponds to the header + files located in llvm/include/ADT/ + and llvm/include/Support/. -llvm/projects - + + llvm/projects + + + 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. + to set up your own project. -llvm/runtime - + + llvm/runtime + -This directory contains libraries which are compiled into LLVM bytecode and + + +This directory contains libraries which are compiled into LLVM bitcode and used when linking programs with the GCC front end. Most of these libraries are skeleton versions of real libraries; for example, libc is a stripped down version of glibc. @@ -1287,33 +1540,45 @@ end to compile. -llvm/test - + + llvm/test + + + 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-test - - 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 + + test-suite + + + + This is not a directory in the normal llvm module; it is a separate + Subversion + module that must be checked out (usually to projects/test-suite). + 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 + suite for LLVM. It is a separate Subversion 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. -llvm/tools - + + llvm/tools + + + 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 +always get help for a tool by typing tool_name -help. The following is a brief introduction to the most important tools. More detailed information is in the Command Guide. @@ -1327,34 +1592,24 @@ information is in the Command Guide. href="HowToSubmitABug.html">HowToSubmitABug.html for more information on using bugpoint. - llvmc - The LLVM Compiler Driver. This program can - be configured to utilize both LLVM and non-LLVM compilation tools to enable - pre-processing, translation, optimization, assembly, and linking of programs - all from one command line. llvmc also takes care of processing the - dependent libraries found in bytecode. This reduces the need to get the - traditional -l<name> options right on the command line. Please - note that this tool, while functional, is still experimental and not feature - complete. - llvm-ar The archiver produces an archive containing - the given LLVM bytecode files, optionally with an index for faster + the given LLVM bitcode files, optionally with an index for faster lookup. llvm-as The assembler transforms the human readable LLVM assembly to LLVM - bytecode. + bitcode. llvm-dis - The disassembler transforms the LLVM bytecode to human readable + The disassembler transforms the LLVM bitcode to human readable LLVM assembly. llvm-ld llvm-ld is a general purpose and extensible linker for LLVM. - This is the linker invoked by llvmc. It performsn standard link time - optimizations and allows optimization modules to be loaded and run so that - language specific optimizations can be applied at link time. + It performs standard link time optimizations and allows optimization + modules to be loaded and run so that language specific optimizations can + be applied at link time. llvm-link llvm-link, not surprisingly, links multiple LLVM modules into @@ -1362,42 +1617,42 @@ information is in the Command Guide. lli lli is the LLVM interpreter, which - can directly execute LLVM bytecode (although very slowly...). In addition - to a simple interpreter, lli also has a tracing mode (entered by - specifying -trace on the command line). Finally, for - architectures that support it (currently x86, Sparc, and PowerPC), by default, - lli will function as a Just-In-Time compiler (if the - functionality was compiled in), and will execute the code much - faster than the interpreter. + can directly execute LLVM bitcode (although very slowly...). For architectures + that support it (currently x86, Sparc, and PowerPC), by default, lli + will function as a Just-In-Time compiler (if the functionality was compiled + in), and will execute the code much faster than the interpreter. llc llc is the LLVM backend compiler, which - translates LLVM bytecode to a native code assembly file or to C code (with + translates LLVM bitcode to a native code assembly file or to C code (with the -march=c option). llvm-gcc llvm-gcc is a GCC-based C frontend that has been retargeted to use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM - byte code or assembly (with the -emit-llvm option) instead of the + bitcode or assembly (with the -emit-llvm option) instead of the usual machine code output. It works just like any other GCC compiler, taking the typical -c, -S, -E, -o options that are typically used. Additionally, the the source code for llvm-gcc is available as a - separate CVS module. + separate Subversion module. opt - opt reads LLVM bytecode, applies a series of LLVM to LLVM + opt reads LLVM bitcode, applies a series of LLVM to LLVM transformations (which are specified on the command line), and then outputs - the resultant bytecode. The 'opt --help' command is a good way to - get a list of the program transformations available in LLVM. + the resultant bitcode. The 'opt -help' command is a good way to + get a list of the program transformations available in LLVM. opt can also be used to run a specific analysis on an input - LLVM bytecode file and print out the results. It is primarily useful for + LLVM bitcode file and print out the results. It is primarily useful for debugging analyses, or familiarizing yourself with what an analysis does. -llvm/utils - + + llvm/utils + + + This directory contains utilities for working with LLVM source code, and some of the utilities are actually required as part of the build process because they @@ -1410,14 +1665,6 @@ are code generators for parts of LLVM infrastructure. assuming that the other generates correct output. For the full user manual, run `perldoc codegen-diff'. - cvsupdate cvsupdate is a script that will - update your CVS tree, but produce a much cleaner and more organized output - than simply running `cvs -z3 up -dP' will. For example, it will group - together all the new and updated files and modified files in separate - sections, so you can see at a glance what has changed. If you are at the - top of your LLVM CVS tree, running utils/cvsupdate is the - preferred way of updating the tree. - emacs/ The emacs directory contains syntax-highlighting files which will work with Emacs and XEmacs editors, providing syntax highlighting support for LLVM assembly files and TableGen @@ -1445,7 +1692,7 @@ are code generators for parts of LLVM infrastructure. directory, switch to directory llvm/tools/llc and build it, causing a re-linking of LLC. - NightlyTest.pl and + NewNightlyTest.pl and NightlyTestTemplate.html These files are used in a cron script to generate nightly status reports of the functionality of tools, and the results can be seen by following the appropriate link on @@ -1466,75 +1713,74 @@ are code generators for parts of LLVM infrastructure. - -llvm/win32 - - 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. - + - + An Example Using the LLVM Tool Chain - + - + This section gives an example of using LLVM. llvm-gcc3 is now obsolete, -so we only include instructiosn for llvm-gcc4. +so we only include instructions 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 +create bitcode by default: gcc4 produces native code. As the example below illustrates, +the '--emit-llvm' flag is needed to produce LLVM bitcode output. For makefiles and +configure scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode output. - -Example with llvm-gcc4 + + Example with llvm-gcc4 + - + - First, create a simple C file, name it 'hello.c': - - #include <stdio.h> - int main() { - printf("hello world\n"); - return 0; - } - + First, create a simple C file, name it 'hello.c': + + ++#include <stdio.h> + +int main() { + printf("hello world\n"); + return 0; +} + Next, compile the C file into a native executable: - % llvm-gcc hello.c -o hello + % llvm-gcc hello.c -o hello Note that llvm-gcc works just like GCC by default. The standard -S and -c arguments work as usual (producing a native .s or .o file, - respectively). + respectively). + + Next, compile the C file into a LLVM bitcode file: - Next, compile the C file into a LLVM bytecode file: - % llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc + + % llvm-gcc -O3 -emit-llvm hello.c -c -o hello.bc The -emit-llvm option can be used with the -S or -c options to emit an LLVM ".ll" or ".bc" file (respectively) for the code. This allows you to use the standard LLVM tools on - the bytecode file. + the bitcode file. Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments. Run the program in both forms. To run the program, use: - % ./hello + % ./hello and - % lli hello.bc + % lli hello.bc The second examples shows how to invoke the LLVM JIT, lli. @@ -1542,21 +1788,28 @@ output. Use the llvm-dis utility to take a look at the LLVM assembly code: - % llvm-dis < hello.bc | less + +llvm-dis < hello.bc | less + Compile the program to native assembly using the LLC code generator: - % llc hello.bc -o hello.s + % llc hello.bc -o hello.s Assemble the native assembly language file into a program: - Solaris:% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native - Others:% gcc hello.s -o hello.native + ++Solaris: % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native + +Others: % gcc hello.s -o hello.native + + Execute the native code program: - % ./hello.native + % ./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. @@ -1566,14 +1819,15 @@ output. + - + Common Problems - + - + If you are having problems building or using LLVM, or if you have any other general questions about LLVM, please consult the Frequently @@ -1582,14 +1836,14 @@ Asked Questions page. - + Links - + - + -This document is just an introduction to how to use LLVM to do + This document is just an introduction on how to use LLVM to do some simple things... there are many more interesting and complicated things that you can do that aren't documented here (but we'll gladly accept a patch if you want to write something up!). For more information about LLVM, check @@ -1609,13 +1863,13 @@ out: + src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"> + src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"> Chris Lattner Reid Spencer - The LLVM Compiler Infrastructure + The LLVM Compiler Infrastructure Last modified: $Date$

Getting Started with the LLVM System -

+ Overview +

+ Getting Started Quickly (A Summary) +

+ Requirements +

+ Hardware +

+ Software +

+ Broken versions of GCC and other tools +

+ Getting Started with LLVM +

Terminology and Notation -

Setting Up Your Environment -

Unpacking the LLVM Archives -

+ Checkout LLVM from Subversion +

+ GIT mirror +

Sending patches with Git

For developers to work with git-svn

Install the GCC Front End -

Local LLVM Configuration -

Compiling the LLVM Suite Source Code -

Cross-Compiling LLVM -

The Location of LLVM Object Files -

Optional Configuration Items -

+ Program Layout +

+ `llvm/examples` +

+ `llvm/include` +

+ `llvm/lib` +

+ `llvm/projects` +

+ `llvm/runtime` +

+ `llvm/test` +

+ `test-suite` +

+ `llvm/tools` +

+ `llvm/utils` +

An Example Using the LLVM Tool Chain -

+ Example with llvm-gcc4 +

Common Problems -

Links -