From 00c73d2e2110e957c5e9395efadbd73cbac3a05b Mon Sep 17 00:00:00 2001 From: Misha Brukman Date: Fri, 7 Nov 2003 19:43:14 +0000 Subject: [PATCH] Completely hacked apart the file and put it back together using stylesheets. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9786 91177308-0d34-0410-b5e6-96231b3b80d8 --- docs/GettingStarted.html | 2032 +++++++++++++++++++------------------- 1 file changed, 1040 insertions(+), 992 deletions(-) diff --git a/docs/GettingStarted.html b/docs/GettingStarted.html index 3aab1932ffb..3eae0d10bb6 100644 --- a/docs/GettingStarted.html +++ b/docs/GettingStarted.html @@ -1,1049 +1,1097 @@ - + - - Getting Started with LLVM System - + + Getting Started with LLVM System + + + - -

Getting Started with the LLVM System
By: Guochun Shi, - Chris Lattner, - John Criswell, - Misha Brukman, and - Vikram Adve -

+
+ Getting Started with the LLVM System +
- -

Contents

- - - - - - -
-

Overview

-
-
- - - Welcome to LLVM! In order to get started, you first need to know some - basic information. - -

- 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 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 compiled into LLVM bytecode, a program can be - manipulated with the LLVM tools from the LLVM suite. - - -

-

Getting Started Quickly (A Summary)

-
-
- - - Here's the short story for getting up and running quickly with LLVM: + - -

- -

  • Configure the LLVM Build Environment -
      -
    1. Change directory to where you want to store the LLVM object - files and run configure to configure the Makefiles and - header files for the default platform. - Useful options include: -
        -
      • --with-llvmgccdir=directory -
        - Specify where the LLVM GCC frontend is installed. -

        - -

      • --enable-spec2000=directory -
        - Enable the SPEC2000 benchmarks for testing. The SPEC2000 - benchmarks should be available in directory. -
      -
    - -

    - -

  • Build the LLVM Suite -
      -
    1. Set your LLVM_LIB_SEARCH_PATH environment variable. -
    2. gmake -k |& tee gnumake.out -    # this is csh or tcsh syntax -
    - -

    - - - -

    - 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 GCC 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: - - - 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 - bytecode. Code 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. -

    - - -

    Software

    - -

    - - 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: -

    - - - - -

    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. - A complete guide to installation is provided in the - next section. - -

    The later sections of this guide describe the 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. - - -

    -

    Getting Started with LLVM

    -
    -
    - - - -

    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). -

    - -

    LLVMGCCDIR -
    - This is the where the LLVM GCC Front End is installed. -

    - For the pre-built GCC front end binaries, the LLVMGCCDIR is - cfrontend/platform/llvm-gcc. -

    - - -

    Setting Up Your Environment

    - - -

    - 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. - -

    -
    LLVM_LIB_SEARCH_PATH=LLVMGCCDIR/bytecode-libs -
    - This environment variable helps the LLVM GCC front end find bytecode - libraries that it will need for compilation. -

    - -

    alias llvmgcc LLVMGCCDIR/bin/gcc -
    alias llvmg++ LLVMGCCDIR/bin/g++ -
    - This alias allows you to use the LLVM C and C++ front ends without putting - them in your PATH or typing in their complete pathnames. -
    - - -

    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 three files. Each - file is a TAR archive that is compressed with the gzip program. -

    - -

    The three files are as follows: -

    -
    llvm.tar.gz -
    This is the source code to the LLVM suite. -

    - -

    cfrontend.sparc.tar.gz -
    This is the binary release of the GCC front end for Solaris/Sparc. -

    - -

    cfrontend.x86.tar.gz -
    This is the binary release of the GCC front end for Linux/x86. -
    - - -

    Checkout LLVM from CVS

    - - -

    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 - follows: -

    - -

    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.

    - -

    - Note that the GCC front end is not included in the CVS repository. You - should have downloaded the binary distribution for your platform. -

    - - -

    Install the GCC Front End

    - - -

    - 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. -

    - -

    - To install the GCC front end, do the following: +

  • Getting Started with LLVM
      -
    1. cd where-you-want-the-front-end-to-live -
    2. gunzip --stdout cfrontend.platform.tar.gz | tar -xvf - - -
    +
  • Terminology and Notation +
  • Setting Up Your Environment +
  • Unpacking the LLVM Archives +
  • Checkout LLVM from CVS +
  • Install the GCC Front End +
  • Local LLVM Configuration +
  • Compiling the LLVM Suite Source Code +
  • The Location of LLVM Object Files +
    • - If you are on a Sparc/Solaris machine, you will need to fix the header - files: +
  • Program layout +
      +
    1. CVS directories +
    2. llvm/include +
    3. llvm/lib +
    4. llvm/runtime +
    5. llvm/test +
    6. llvm/tools +
    7. llvm/utils +
    • +
  • An Example Using the LLVM Tool Chain +
  • Common Problems +
  • Links + + +

    By: + Guochun Shi, + Chris Lattner, + John Criswell, + Misha Brukman, and + Vikram Adve.

    + + + +
    + Overview +
    + + +
    + +

    Welcome to LLVM! In order to get started, you first need to know some +basic information.

    + +

    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 +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 +compiled into LLVM bytecode, a program can be manipulated with the LLVM tools +from the LLVM suite.

    + +
    + + +
    + Getting Started Quickly (A Summary) +
    + + +
    + +

    Here's the short story for getting up and running quickly with LLVM:

    + +
      +
    1. Install the GCC front end: +
        +
      1. cd where-you-want-the-C-front-end-to-live +
      2. gunzip --stdout cfrontend.platform.tar.gz | tar -xvf - +
      3. Sparc Only:
        + cd cfrontend/sparc
        + ./fixheaders         +
      2. + +
    2. Get the Source Code +
        +
      • With the distributed files: +
          +
        1. cd where-you-want-llvm-to-live +
        2. gunzip --stdout llvm.tar.gz | tar -xvf - +
        3. cd llvm +
        • + +
      • With anonymous CVS access: +
          +
        1. cd where-you-want-llvm-to-live
          2. +
        2. cvs -d + :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login
          3. +
        3. Hit the return key when prompted for the password. +
        4. cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm + co llvm
          5. +
        5. cd llvm
          6. +
        • +
      3. + +
    3. Configure the LLVM Build Environment +
        +
      1. Change directory to where you want to store the LLVM object + files and run configure to configure the Makefiles and + header files for the default platform. Useful options include: +
          +
        • --with-llvmgccdir=directory +

          Specify where the LLVM GCC frontend is installed.

          • +
        • --enable-spec2000=directory +

          Enable the SPEC2000 benchmarks for testing. The SPEC2000 + benchmarks should be available in + directory.

          • +
        +
      4. + +
    4. Build the LLVM Suite: +
        +
      1. Set your LLVM_LIB_SEARCH_PATH environment variable. +
      2. gmake -k |& tee gnumake.out +    # this is csh or tcsh syntax +
      + +
    + +

    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 GCC 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:

    + +
      + +
    • Linux on x86 (Pentium and above) +
        +
      • Approximately 760 MB of Free Disk Space +
          +
        • Source code: 30 MB
          • +
        • Object code: 670 MB
          • +
        • GCC front end: 60 MB
          • +
        • +
      • + +
    • Solaris on SparcV9 (Ultrasparc) +
        +
      • Approximately 1.24 GB of Free Disk Space +
          +
        • Source code: 30 MB
          • +
        • Object code: 1000 MB
          • +
        • GCC front end: 210 MB
          • +
        • +
      • + +
    + +

    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 bytecode. Code +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.

    + +
    + + +
    + Software +
    + +
    + +

    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:

    + +
      +
    • GNU Autoconf +
    • GNU M4 + +

      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).

      • + +
    • QMTest
      • +
    • Python + +

      These are needed to use the LLVM test suite.

      • + +
    + + +

    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. +A complete guide to installation is provided in the +next section.

    + +

    The later sections of this guide describe the 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.

    + +
    + + +
    + Getting Started with LLVM +
    + + + +
    + 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.

    - - cd cfrontend/sparc +

    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). +

    + +

    LLVMGCCDIR +
    + This is the where the LLVM GCC Front End is installed. +

    + For the pre-built GCC front end binaries, the LLVMGCCDIR is + cfrontend/platform/llvm-gcc. +

    + +
    + + +
    + Setting Up Your Environment +
    + +
    + +

    +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. + +

    +
    LLVM_LIB_SEARCH_PATH=LLVMGCCDIR/bytecode-libs +
    + This environment variable helps the LLVM GCC front end find bytecode + libraries that it will need for compilation. +

    + +

    alias llvmgcc LLVMGCCDIR/bin/gcc +
    alias llvmg++ LLVMGCCDIR/bin/g++ +
    + This alias allows you to use the LLVM C and C++ front ends without putting + them in your PATH or typing in their complete pathnames. +
    + +
    + + +
    + 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 three files. Each +file is a TAR archive that is compressed with the gzip program. +

    + +

    The three files are as follows: +

    +
    llvm.tar.gz +
    This is the source code to the LLVM suite. +

    + +

    cfrontend.sparc.tar.gz +
    This is the binary release of the GCC front end for Solaris/Sparc. +

    + +

    cfrontend.x86.tar.gz +
    This is the binary release of the GCC front end for Linux/x86. +
    + +
    + + +
    + Checkout LLVM from CVS +
    + +
    + +

    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 +follows:

    + +
      +
    • cd where-you-want-llvm-to-live +
    • cvs -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm login +
    • Hit the return key when prompted for the password. +
    • cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co + 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.

    + +

    Note that the GCC front end is not included in the CVS repository. You +should have downloaded the binary distribution for your platform.

    + +
    + + +
    + Install the GCC Front End +
    + +
    + +

    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.

    + +

    To install the GCC front end, do the following:

    + +
      +
    1. cd where-you-want-the-front-end-to-live
      2. +
    2. gunzip --stdout cfrontend.platform.tar.gz | tar -xvf + -
      3. +
    + +

    If you are on a Sparc/Solaris machine, you will need to fix the header +files:

    + +

    cd cfrontend/sparc
    + ./fixheaders

    + +

    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.

    + +

    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.

    + +
    + + +
    + Local LLVM Configuration +
    + +
    + +

    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 build LLVM.

    + +

    The following environment variables are used by the configure +script to configure the build system:

    + + + + + + + + + + + + + + + + +
    VariablePurpose
    CCTells 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.
    CXXTells 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:

    + +
    +
    --with-llvmgccdir=LLVMGCCDIR +
    + Path to the location where the LLVM C front end binaries and + associated libraries will be installed. +

    +

    --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). +

    +

    --enable-jit +
    + Compile the Just In Time (JIT) 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-spec2000 +
    --enable-spec2000=<directory> +
    + Enable the use of SPEC2000 when testing LLVM. This is disabled by default + (unless configure finds SPEC2000 installed). By specifying + directory, you can tell configure where to find the SPEC2000 + benchmarks. If directory is left unspecified, configure + uses the default value + /home/vadve/shared/benchmarks/speccpu2000/benchspec. +
    + +

    To configure LLVM, follow these steps:

    + +
      +
    1. Change directory into the object root directory:
      - ./fixheaders -       - + cd OBJ_ROOT

      - 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. -

      +
    2. Run the configure script located in the LLVM source tree: +
      + SRC_ROOT/configure

      - 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. -

      - -

      Local LLVM Configuration

      - +
    -

    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 build LLVM. +

    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 for the bytecode-libs subdirectory of the GCC front end +install, 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.

    -

    - The following environment variables are used by the configure - script to configure the build system: -

    +
    - - - - - + +
    + Compiling the LLVM Suite Source Code +
    - - - - +
    -
    - - - -
    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. -
    +

    Once you have configured LLVM, you can build it. There are three types of +builds:

    -

    - The following options can be used to set or enable LLVM specific options: -

    - -
    -
    --with-llvmgccdir=LLVMGCCDIR +
    +
    Debug Builds
    - Path to the location where the LLVM C front end binaries and - associated libraries will be installed. -

    -

    --enable-optimized + 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. +

    + +

    Release (Optimized) Builds
    - 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). -

    -

    --enable-jit + 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. +

    + +

    Profile Builds
    - Compile the Just In Time (JIT) 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-spec2000 -
    --enable-spec2000=<directory> -
    - Enable the use of SPEC2000 when testing LLVM. This is disabled by default - (unless configure finds SPEC2000 installed). By specifying - directory, you can tell configure where to find the SPEC2000 - benchmarks. If directory is left unspecified, configure - uses the default value - /home/vadve/shared/benchmarks/speccpu2000/benchspec. -
    - -

    - To configure LLVM, follow these steps: -

      -
    1. Change directory into the object root directory: -
      - cd OBJ_ROOT -

      - -

    2. Run the configure script located in the LLVM source tree: -
      - SRC_ROOT/configure -

      -

    -

    - - 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 for the bytecode-libs subdirectory of the GCC front end - install, 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.

    - - -

    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 types gmake (unless the - --enable-optimized option was used during configuration). The - build system will compile the tools and libraries with debugging - information. -

    - -

    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. -

    - -

    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: -

    - gmake - -

    - 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 - -

    - 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 distclean -
    - 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 files into the proper location. For the most part, - this does nothing, but it does install bytecode libraries into the - GCC front end's bytecode library directory. If you need to update - your bytecode libraries, this is the target to use once you've built - them. -

    - -

    - - 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_PROFILING=1 -
    - Perform a Profiling build. -

    - -

    gmake VERBOSE=1 -
    - Print what gmake is doing on standard output. -

    -

    - - 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. - - -

    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: -

      - cd OBJ_ROOT - -

    • Run the configure script found in the LLVM source directory: -

      - SRC_ROOT/configure -

    - -

    - The LLVM build will place files underneath OBJ_ROOT in directories - named after the build type: -

    - -
    -
    Debug Builds -
    -
    -
    Tools -
    OBJ_ROOT/tools/Debug -
    Libraries -
    OBJ_ROOT/lib/Debug -
    -

    - -

    Release Builds -
    -
    -
    Tools -
    OBJ_ROOT/tools/Release -
    Libraries -
    OBJ_ROOT/lib/Release -
    -

    - -

    Profile Builds -
    -
    -
    Tools -
    OBJ_ROOT/tools/Profile -
    Libraries -
    OBJ_ROOT/lib/Profile -
    -
    - - -
    -

    Program Layout

    -
    -
    - - -

    - One useful source of information about the LLVM source base is the LLVM doxygen documentation, available at http://llvm.cs.uiuc.edu/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 public header files exported from the LLVM - library. The three main subdirectories of this directory are:

    - -

      -
    1. llvm/include/llvm - This directory contains all of the LLVM - specific header files. This directory also has subdirectories for - different portions of LLVM: Analysis, CodeGen, - Target, Transforms, etc... - -
    2. llvm/include/Support - This directory contains generic - support libraries that are independent of LLVM, but are used by LLVM. - For example, some C++ STL utilities and a Command Line option processing - library store their header files here. - -
    3. llvm/include/Config - This directory contains header files - configured by the configure script. They wrap "standard" UNIX - and C header files. Source code can include these header files which - automatically take care of the conditional #includes that the - configure script generates. -
    - - -

    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 - different tools.

    - -

    -
    llvm/lib/VMCore/
    This directory holds the core LLVM - source files that implement core classes like Instruction and BasicBlock. - -
    llvm/lib/AsmParser/
    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/CWriter/
    This directory implements the LLVM to C - converter. - -
    llvm/lib/Analysis/
    This directory contains a variety of - different program analyses, such as Dominator Information, Call Graphs, - Induction Variables, Interval Identification, Natural Loop Identification, - etc... - -
    llvm/lib/Transforms/
    This directory contains the source - code for the LLVM to LLVM program transformations, such as Aggressive Dead - Code Elimination, Sparse Conditional Constant Propagation, Inlining, Loop - Invariant Code Motion, Dead Global Elimination, and many others... - -
    llvm/lib/Target/
    This directory contains files that - describe various target architectures for code generation. For example, - the llvm/lib/Target/Sparc directory holds the Sparc machine - description.
    - -
    llvm/lib/CodeGen/
    This directory contains the major parts - of the code generator: Instruction Selector, Instruction Scheduling, and - Register Allocation. - -
    llvm/lib/Support/
    This directory contains the source code - that corresponds to the header files located in - llvm/include/Support/. -
    - - -

    llvm/runtime

    - - -

    - This directory contains libraries which are compiled into LLVM bytecode 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. -

    - -

    - Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front end - to compile. -

    - - -

    llvm/test

    - - -

    This directory contains regression tests and source code that is used to - test the LLVM infrastructure. -

    - - -

    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 - following is a brief introduction to the most important tools.

    - -
    -
    - -
    analyze
    analyze is used to run a specific - analysis on an input LLVM bytecode file and print out the results. It is - primarily useful for debugging analyses, or familiarizing yourself with - what an analysis does.

    - -

    bugpoint
    bugpoint is used to debug - optimization passes or code generation backends by narrowing down the - given test case to the minimum number of passes and/or instructions that - still cause a problem, whether it is a crash or miscompilation. See HowToSubmitABug.html for more information - on using bugpoint.

    - -

    llvm-ar
    The archiver produces an archive containing - the given LLVM bytecode files, optionally with an index for faster - lookup.

    - -

    llvm-as
    The assembler transforms the human readable - LLVM assembly to LLVM bytecode.

    - -

    llvm-dis
    The disassembler transforms the LLVM - bytecode to human readable LLVM assembly. Additionally, it can convert - LLVM bytecode to C, which is enabled with the -c option.

    - -

    llvm-link
    llvm-link, not surprisingly, - links multiple LLVM modules into a single program.

    - -

    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 only x86 and Sparc), 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 SPARC or x86 assembly file.

    - -

    llvmgcc
    llvmgcc is a GCC-based C frontend - that has been retargeted to emit LLVM code as the machine code output. It - works just like any other GCC compiler, taking the typical -c, -S, -E, - -o options that are typically used. The source code for the - llvmgcc tool is currently not included in the LLVM CVS tree - because it is quite large and not very interesting.

    - -

      -
      gccas
      This tool is invoked by the - llvmgcc frontend as the "assembler" part of the compiler. This - tool actually assembles LLVM assembly to LLVM bytecode, - performs a variety of optimizations, and outputs LLVM bytecode. Thus - when you invoke llvmgcc -c x.c -o x.o, you are causing - gccas to be run, which writes the x.o file (which is - an LLVM bytecode file that can be disassembled or manipulated just like - any other bytecode file). The command line interface to gccas - is designed to be as close as possible to the system - `as' utility so that the gcc frontend itself did not have to be - modified to interface to a "weird" assembler.

      - -

      gccld
      gccld links together several LLVM - bytecode files into one bytecode file and does some optimization. It is - the linker invoked by the GCC frontend when multiple .o files need to be - linked together. Like gccas, the command line interface of - gccld is designed to match the system linker, to aid - interfacing with the GCC frontend.

      -

    - -
    opt
    opt reads LLVM bytecode, 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.

    - -

    - - -

    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 are code generators for parts of LLVM infrastructure. - -
    - Burg/
    Burg is an instruction selector - generator -- it builds trees on which it then performs pattern-matching to - select instructions according to the patterns the user has specified. Burg - is currently used in the Sparc V9 backend.

    - -

    codegen-diff
    codegen-diff is a script - that finds differences between code that LLC generates and code that LLI - generates. This is a useful tool if you are debugging one of them, - 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 - description files. For information on how to use the syntax files, consult - the README file in that directory.

    - -

    getsrcs.sh
    The getsrcs.sh script finds - and outputs all non-generated source files, which is useful if one wishes - to do a lot of development across directories and does not want to - individually find each file. One way to use it is to run, for example: - xemacs `utils/getsources.sh` from the top of your LLVM source - tree.

    - -

    makellvm
    The makellvm script compiles all - files in the current directory and then compiles and links the tool that - is the first argument. For example, assuming you are in the directory - llvm/lib/Target/Sparc, if makellvm is in your path, - simply running makellvm llc will make a build of the current - directory, switch to directory llvm/tools/llc and build it, - causing a re-linking of LLC.

    - -

    NightlyTest.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 - the LLVM homepage.

    - -

    TableGen/
    The TableGen directory contains - the tool used to generate register descriptions, instruction set - descriptions, and even assemblers from common TableGen description - files.

    - -

    vim/
    The vim directory contains - syntax-highlighting files which will work with the VIM editor, providing - syntax highlighting support for LLVM assembly files and TableGen - description files. For information on how to use the syntax files, consult - the README file in that directory.

    - -

    - - -

    -
    An Example Using the LLVM Tool Chain
    -

    -
    - - -
      -
    1. First, create a simple C file, name it 'hello.c': + 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:

    + +

    gmake

    + +

    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

    + +

    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 distclean +
    + 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 files into the proper location. For the most part, + this does nothing, but it does install bytecode libraries into the + GCC front end's bytecode library directory. If you need to update + your bytecode libraries, this is the target to use once you've built + them. +

    +

    + +

    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_PROFILING=1 +
    + Perform a Profiling build. +

    + +

    gmake VERBOSE=1 +
    + Print what gmake is doing on standard output. +

    +

    + +

    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.

    + + + + +
    + 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:

      + +

      cd OBJ_ROOT

      • + +

    • Run the configure script found in the LLVM source + directory:

      + +

      SRC_ROOT/configure

      • +
    + +

    The LLVM build will place files underneath OBJ_ROOT in directories +named after the build type:

    + +
    +
    Debug Builds +
    +
    +
    Tools +
    OBJ_ROOT/tools/Debug +
    Libraries +
    OBJ_ROOT/lib/Debug +
    +

    + +

    Release Builds +
    +
    +
    Tools +
    OBJ_ROOT/tools/Release +
    Libraries +
    OBJ_ROOT/lib/Release +
    +

    + +

    Profile Builds +
    +
    +
    Tools +
    OBJ_ROOT/tools/Profile +
    Libraries +
    OBJ_ROOT/lib/Profile +
    +
    + +
    + + +
    + Program Layout +
    + + +
    + +

    One useful source of information about the LLVM source base is the LLVM doxygen documentation, available at http://llvm.cs.uiuc.edu/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 public header files exported from the LLVM +library. The three main subdirectories of this directory are:

    + +
      +
    1. llvm/include/llvm - This directory contains all of the LLVM + specific header files. This directory also has subdirectories for + different portions of LLVM: Analysis, CodeGen, + Target, Transforms, etc...
      2. + +
    2. llvm/include/Support - This directory contains generic + support libraries that are independent of LLVM, but are used by LLVM. + For example, some C++ STL utilities and a Command Line option processing + library store their header files here.
      3. + +
    3. llvm/include/Config - This directory contains header files + configured by the configure script. They wrap "standard" UNIX + and C header files. Source code can include these header files which + automatically take care of the conditional #includes that the + configure script generates.
      4. +
    + +
    + + +
    + 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 +different tools.

    + +
    +
    llvm/lib/VMCore/
    This directory holds the core LLVM + source files that implement core classes like Instruction and BasicBlock. + +
    llvm/lib/AsmParser/
    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/CWriter/
    This directory implements the LLVM to C + converter. + +
    llvm/lib/Analysis/
    This directory contains a variety of + different program analyses, such as Dominator Information, Call Graphs, + Induction Variables, Interval Identification, Natural Loop Identification, + etc... + +
    llvm/lib/Transforms/
    This directory contains the source + code for the LLVM to LLVM program transformations, such as Aggressive Dead + Code Elimination, Sparse Conditional Constant Propagation, Inlining, Loop + Invariant Code Motion, Dead Global Elimination, and many others... + +
    llvm/lib/Target/
    This directory contains files that + describe various target architectures for code generation. For example, + the llvm/lib/Target/Sparc directory holds the Sparc machine + description.
    + +
    llvm/lib/CodeGen/
    This directory contains the major parts + of the code generator: Instruction Selector, Instruction Scheduling, and + Register Allocation. + +
    llvm/lib/Support/
    This directory contains the source code + that corresponds to the header files located in + llvm/include/Support/. +
    + +
    + + +
    + llvm/runtime +
    + +
    + +

    This directory contains libraries which are compiled into LLVM bytecode 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.

    + +

    Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front +end to compile.

    + +
    + + +
    + llvm/test +
    + +
    + +

    This directory contains regression tests and source code that is used to test +the LLVM infrastructure.

    + +
    + + +
    + 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 +following is a brief introduction to the most important tools.

    + +
    +
    + +
    analyze
    analyze is used to run a specific + analysis on an input LLVM bytecode file and print out the results. It is + primarily useful for debugging analyses, or familiarizing yourself with + what an analysis does.

    + +

    bugpoint
    bugpoint is used to debug + optimization passes or code generation backends by narrowing down the + given test case to the minimum number of passes and/or instructions that + still cause a problem, whether it is a crash or miscompilation. See HowToSubmitABug.html for more information + on using bugpoint.

    + +

    llvm-ar
    The archiver produces an archive containing + the given LLVM bytecode files, optionally with an index for faster + lookup.

    + +

    llvm-as
    The assembler transforms the human readable + LLVM assembly to LLVM bytecode.

    + +

    llvm-dis
    The disassembler transforms the LLVM + bytecode to human readable LLVM assembly. Additionally, it can convert + LLVM bytecode to C, which is enabled with the -c option.

    + +

    llvm-link
    llvm-link, not surprisingly, + links multiple LLVM modules into a single program.

    + +

    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 only x86 and Sparc), 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 SPARC or x86 assembly file.

    + +

    llvmgcc
    llvmgcc is a GCC-based C frontend + that has been retargeted to emit LLVM code as the machine code output. It + works just like any other GCC compiler, taking the typical -c, -S, -E, + -o options that are typically used. The source code for the + llvmgcc tool is currently not included in the LLVM CVS tree + because it is quite large and not very interesting.

    + +

      +
      gccas
      This tool is invoked by the + llvmgcc frontend as the "assembler" part of the compiler. This + tool actually assembles LLVM assembly to LLVM bytecode, + performs a variety of optimizations, and outputs LLVM bytecode. Thus + when you invoke llvmgcc -c x.c -o x.o, you are causing + gccas to be run, which writes the x.o file (which is + an LLVM bytecode file that can be disassembled or manipulated just like + any other bytecode file). The command line interface to gccas + is designed to be as close as possible to the system + `as' utility so that the gcc frontend itself did not have to be + modified to interface to a "weird" assembler.

      + +

      gccld
      gccld links together several LLVM + bytecode files into one bytecode file and does some optimization. It is + the linker invoked by the GCC frontend when multiple .o files need to be + linked together. Like gccas, the command line interface of + gccld is designed to match the system linker, to aid + interfacing with the GCC frontend.

      +

    + +
    opt
    opt reads LLVM bytecode, 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.

    + +

    + +
    + + +
    + 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 +are code generators for parts of LLVM infrastructure.

    + +
    + Burg/
    Burg is an instruction selector + generator -- it builds trees on which it then performs pattern-matching to + select instructions according to the patterns the user has specified. Burg + is currently used in the Sparc V9 backend.

    + +

    codegen-diff
    codegen-diff is a script + that finds differences between code that LLC generates and code that LLI + generates. This is a useful tool if you are debugging one of them, + 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 + description files. For information on how to use the syntax files, consult + the README file in that directory.

    + +

    getsrcs.sh
    The getsrcs.sh script finds + and outputs all non-generated source files, which is useful if one wishes + to do a lot of development across directories and does not want to + individually find each file. One way to use it is to run, for example: + xemacs `utils/getsources.sh` from the top of your LLVM source + tree.

    + +

    makellvm
    The makellvm script compiles all + files in the current directory and then compiles and links the tool that + is the first argument. For example, assuming you are in the directory + llvm/lib/Target/Sparc, if makellvm is in your path, + simply running makellvm llc will make a build of the current + directory, switch to directory llvm/tools/llc and build it, + causing a re-linking of LLC.

    + +

    NightlyTest.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 + the LLVM homepage.

    + +

    TableGen/
    The TableGen directory contains + the tool used to generate register descriptions, instruction set + descriptions, and even assemblers from common TableGen description + files.

    + +

    vim/
    The vim directory contains + syntax-highlighting files which will work with the VIM editor, providing + syntax highlighting support for LLVM assembly files and TableGen + description files. For information on how to use the syntax files, consult + the README file in that directory.

    + +

    + +
    + + +
    + An Example Using the LLVM Tool Chain +
    + + +
    + +
      +
    1. First, create a simple C file, name it 'hello.c': 
          #include <stdio.h>
    int main() {
      printf("hello world\n");
      return 0;
    }
-
      +
      2. -
    2. Next, compile the C file into a LLVM bytecode file:

      +

    3. Next, compile the C file into a LLVM bytecode file:

      +

      % llvmgcc hello.c -o hello

      - % llvmgcc hello.c -o hello

      - - This will create two result files: hello and +

      This will create two result files: hello and hello.bc. The hello.bc is the LLVM bytecode that corresponds the the compiled program and the library facilities that it required. hello is a simple shell script that runs the bytecode - file with lli, making the result directly executable.

      + file with lli, making the result directly executable.

      4. -
    4. Run the program. To make sure the program ran, execute one of the - following commands:

      +

    5. Run the program. To make sure the program ran, execute one of the + following commands:

      - % ./hello

      +

      % ./hello

      - or

      +

      or

      - % lli hello.bc

      +

      % lli hello.bc

      6. -
    6. Use the llvm-dis utility to take a look at the LLVM assembly - code:

      +

    7. Use the llvm-dis utility to take a look at the LLVM assembly + code:

      - % llvm-dis < hello.bc | less

      +

      % llvm-dis < hello.bc | less

      8. -
    8. Compile the program to native Sparc assembly using the code - generator (assuming you are currently on a Sparc system):

      +

    9. Compile the program to native Sparc assembly using the code + generator (assuming you are currently on a Sparc system):

      - % llc hello.bc -o hello.s

      +

      % llc hello.bc -o hello.s

      -
    10. Assemble the native sparc assemble file into a program:

      +

    11. Assemble the native sparc assemble file into a program:

      - % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.sparc

      +

      % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.sparc

      -
    12. Execute the native sparc program:

      +

    13. Execute the native sparc program:

      - % ./hello.sparc

      +

      % ./hello.sparc

      14. -
    + +
    - -

    -
    Common Problems
    -

    -
    - + +
    + 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 Asked Questions page. +
    - -

    Links

    -
    - +

    If you are having problems building or using LLVM, or if you have any other +general questions about LLVM, please consult the Frequently +Asked Questions page.

    -

    This document is just an introduction to 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 - out:

    +
    - + +
    + Links +
    + -
    +
    - If you have any questions or run into any snags (or you have any - additions...), please send an email to - Chris Lattner.

    - The LLVM Compiler Infrastructure -
    +

    This document is just an introduction to 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 +out:

    - - -Last modified: Thu Nov 6 14:50:33 CST 2003 - - + + +
    + + + +
    +
    +
    Chris Lattner
    + The LLVM Compiler Infrastructure +
    + Last modified: $Date$ +
    + +