X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=docs%2FGettingStarted.html;h=0e871336deb83ca2aa1345113c8439ded797076a;hb=1d33bb310865528f5b1a303e33891366457bc0ef;hp=7a5fdf5408d0c291e2760f8e2da48d69fee864f0;hpb=7db3f52a9fdfa2d1148ba12a264bb2e24a5b86fe;p=oota-llvm.git diff --git a/docs/GettingStarted.html b/docs/GettingStarted.html index 7a5fdf5408d..0e871336deb 100644 --- a/docs/GettingStarted.html +++ b/docs/GettingStarted.html @@ -31,6 +31,7 @@
  • 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
  • @@ -51,6 +52,9 @@
  • An Example Using the LLVM Tool Chain +
      +
    1. Example with llvm-gcc4
    2. +
  • Common Problems
  • Links @@ -80,12 +84,12 @@ 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 +analyzer and bytecode optimizer. It also contains a test suite that can be used to test the LLVM tools and the GCC front end.

    The second piece is the GCC front end. This component provides a version of GCC that compiles C and C++ code into LLVM bytecode. Currently, the GCC front -end is a modified version of GCC 3.4 (we track the GCC 3.4 development). Once +end uses the GCC parser to convert code to LLVM. Once compiled into LLVM bytecode, a program can be manipulated with the LLVM tools from the LLVM suite.

    @@ -114,11 +118,11 @@ and performance.
  • Install the GCC front end if you intend to compile C or C++:
    1. cd where-you-want-the-C-front-end-to-live
    2. -
    3. gunzip --stdout cfrontend.platform.tar.gz | tar -xvf - +
    4. gunzip --stdout llvm-gcc.platform.tar.gz | tar -xvf -
    5. -
    6. cd cfrontend/platform
      +
    7. cd llvm-gcc3.4/platform (llvm-gcc3.4 only)
      ./fixheaders
    8. -
    9. Add the cfrontend's "bin" directory to your PATH variable
    10. +
    11. Add llvm-gcc's "bin" directory to your PATH variable.
  • Get the LLVM Source Code @@ -156,7 +160,7 @@ and performance. /usr/local).

  • --with-llvmgccdir=directory

    Optionally, specify for directory the full pathname of the - C/C++ FrontEnd installation to use with this LLVM configuration. If + C/C++ front end installation to use with this LLVM configuration. If not specified, the PATH will be searched.

  • --enable-spec2000=directory

    Enable the SPEC2000 benchmarks for testing. The SPEC2000 @@ -169,7 +173,8 @@ and performance.

    1. gmake -k |& tee gnumake.out    # this is csh or tcsh syntax
    2. -
    3. If you get an "internal compiler error (ICE)" see below.
    4. +
    5. If you get an "internal compiler error (ICE)" or test failures, see + below.
    @@ -205,7 +210,7 @@ software you will need.

    LLVM is known to work on the following platforms:

    - +
    @@ -231,14 +236,20 @@ software you will need.

    + + + + + + - + - + @@ -250,7 +261,7 @@ software you will need.

    LLVM has partial support for the following platforms:

    -
    OS Arch PowerPC GCC
    MacOS X2x86GCC
    Cygwin/Win32x861x861,8 GCC 3.4.X, binutils 2.15
    MinGW/Win32x861,6x861,6,8 GCC 3.4.X, binutils 2.15
    +
    @@ -270,39 +281,53 @@ software you will need.

    + + + + + + + + + + + + + + + +
    OS Arch PowerPC GCC
    Linux7AlphaGCC
    Linux7Itanium (IA-64)GCC
    HP-UX7Itanium (IA-64)HP aCC

    Notes:

    -
    -1 - Code generation supported for Pentium processors and up
    -2 - Code generation supported for 32-bit ABI only
    -3 - No native code generation
    -4 - Build is not complete: one or more tools don't link
    -5 - The GCC-based C/C++ frontend does not build
    -6 - The port is done using the MSYS shell. -Download and install -bison (excl. M4.exe) and flex in that order. Build binutils-2.15 from source, -if necessary. If you need to create a library for an MS DLL, do the following: +
      -
    1. pexports /C/WINNT/SYSTEM32/file.dll | sed "s/^_//" > -/C/MinGW/lib/file.def
    2. -
    3. Edit file and append @<ordinal> to the missing function name
    4. -
    5. dlltool.exe -k -d /C/MinGW/lib/file.def -l -/C/MinGW/lib/libfile.a.
    6. +
    7. Code generation supported for Pentium processors and +up
    8. +
    9. Code generation supported for 32-bit ABI only
    10. +
    11. No native code generation
    12. +
    13. Build is not complete: one or more tools don't link
    14. +
    15. The GCC-based C/C++ frontend does not build
    16. +
    17. The port is done using the MSYS shell. +Download and install +bison (excl. M4.exe) and flex in that order. Build binutils-2.15 from source, +if necessary. Bison & flex can be also grabbed from GNUWin32 sf.net +project.
    18. +
    19. Native code generation exists but is not complete.
    20. +
    21. Binutils up to post-2.17 has bug in bfd/cofflink.c + preventing LLVM from building correctly. Several workarounds have been + introduced into LLVM build system, but the bug can occur anytime in the + future. We highly recommend that you rebuild your current binutils with the + patch from + Binutils bugzilla, if it wasn't already applied.

    Note that you will need about 1-3 GB of space for a full LLVM build in Debug -mode, depending on the system (because of all the debug info), and the libraries -appear in more than one of the tools that get linked, so there is some -duplication. If you do not need many of the tools and you are space-conscious, +mode, depending on the system (it is so large because of all the debugging +information and the fact that the libraries are statically linked into multiple +tools). If you do not need many of the tools and you are space-conscious, you can disable them individually in llvm/tools/Makefile. The Release build requires considerably less space.

    @@ -326,7 +351,7 @@ href="CFEBuildInstrs.html">try to compile it on your platform.

    is the usual name for the software package that LLVM depends on. The Version column provides "known to work" versions of the package. The Notes column describes how LLVM uses the package and provides other details.

    - +
    @@ -338,7 +363,13 @@ href="CFEBuildInstrs.html">try to compile it on your platform.

    - + + + + + + + @@ -349,82 +380,84 @@ href="CFEBuildInstrs.html">try to compile it on your platform.

    - + + + + + + + - + - + - + + + + + + + - + - + - - - - - - - + - - - - - - - +
    PackageVersionNotes
    GCC 3.4.2C/C++ compiler (Note 3)C/C++ compiler1
    TeXinfo4.5For building the CFE
    Bison1.351.28, 1.35, 1.75, 1.875d, 2.0, or 2.1
    (not 1.85 or 1.875)
    YACC compiler
    CVS≥1.11CVS access to LLVM2
    DejaGnu 1.4.2Automated test suite (Note 2)Automated test suite3
    tcl 8.3, 8.4Automated test suite (Note 2)Automated test suite3
    expect 5.38.0Automated test suite (Note 2)Automated test suite3
    perl≥5.6.0Nightly tester, utilities
    GNU M4 1.4Macro processor for configuration (Note 1)Macro processor for configuration4
    GNU Autoconf 2.59Configuration script builder (Note 1)Configuration script builder4
    GNU Automake 1.9.2aclocal macro generator (Note 1)
    perl≥5.6.0Nightly tester, utilitiesaclocal macro generator4
    libtool 1.5.10Shared library manager (Note 1)
    CVS≥1.11CVS access to LLVM (Note 4)Shared library manager4
    -

    Notes:

    +

    Notes:

    + +

    Additionally, your compilation host is expected to have the usual plethora of Unix utilities. Specifically:

      @@ -465,8 +498,9 @@ href="CFEBuildInstrs.html">try to compile it on your platform.

      LLVM is very demanding of the host C++ compiler, and as such tends to expose bugs in the compiler. In particular, several versions of GCC crash when trying -to compile LLVM. We routinely use GCC 3.3.3 and GCC 3.4.0 and have had success -with them. Other versions of GCC will probably work as well. GCC versions listed +to compile LLVM. We routinely use GCC 3.3.3, 3.4.0, and Apple 4.0.1 +successfully with them (however, see below). Other versions of GCC will +probably work as well. GCC versions listed here are known to not work. If you are using one of these versions, please try to upgrade your GCC to something more recent. If you run into a problem with a version of GCC not listed here, please let @@ -483,6 +517,35 @@ problems in the STL that effectively prevent it from compiling LLVM.

      GCC 3.3.2: This version of GCC suffered from a serious bug which causes it to crash in the "convert_from_eh_region_ranges_1" GCC function.

      + +

      Cygwin GCC 3.3.3: The version of GCC 3.3.3 commonly shipped with + Cygwin does not work. Please upgrade + to a newer version if possible.

      +

      SuSE GCC 3.3.3: The version of GCC 3.3.3 shipped with SuSE 9.1 (and + possibly others) does not compile LLVM correctly (it appears that exception + handling is broken in some cases). Please download the FSF 3.3.3 or upgrade + to a newer version of GCC.

      +

      GCC 3.4.x on X86-64/amd64: GCC + miscompiles portions of LLVM.

      +

      IA-64 GCC 4.0.0: The IA-64 version of GCC 4.0.0 is known to + miscompile LLVM.

      +

      Apple Xcode 2.3: GCC crashes when compiling LLVM at -O3 (which is the + default with ENABLE_OPTIMIZED=1. To work around this, build with + "ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".

      +

      GCC 4.1.1: GCC fails to build LLVM with template concept check errors + compiling some files. At the time of this writing, GCC mainline (4.2) + did not share the problem.

      +

      GCC 4.1.1 on X86-64/amd64: GCC + miscompiles portions of LLVM when compiling llvm itself into 64-bit + code. LLVM will appear to mostly work but will be buggy, e.g. failing + portions of its testsuite.

      +

      GCC 4.1.2 on OpenSUSE: Seg faults during libstdc++ build and on x86_64 +platforms compiling md5.c gets a mangled constant.

      +

      GNU ld 2.16.X. Some 2.16.X versions of the ld linker will produce very +long warning messages complaining that some ".gnu.linkonce.t.*" symbol was +defined in a discarded section. You can safely ignore these messages as they are +erroneous and the linkage is correct. These messages disappear using ld +2.17.

    @@ -523,21 +586,21 @@ 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 where the LLVM GCC Front End is installed.

    For the pre-built GCC front end binaries, the LLVMGCCDIR is - cfrontend/platform/llvm-gcc. + llvm-gcc/platform/llvm-gcc. @@ -556,9 +619,10 @@ variables.

    LLVM_LIB_SEARCH_PATH=/path/to/your/bytecode/libs
    [Optional] This environment variable helps LLVM linking tools find the - locations of your bytecode libraries. It is provided only a + locations of your bytecode 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 use the bytecode files installed in its + tools and the C/C++ front-end will automatically use the bytecode files + installed in its lib directory.
    @@ -587,23 +651,19 @@ compressed with the gzip program.
    llvm-test-x.y.tar.gz
    Source release for the LLVM test suite.
    -
    cfrontend-x.y.source.tar.gz
    -
    Source release of the GCC front end.
    - -
    cfrontend-x.y.sparc-sun-solaris2.8.tar.gz
    -
    Binary release of the GCC front end for Solaris/Sparc. -
    - -
    cfrontend-x.y.i686-redhat-linux-gnu.tar.gz
    -
    Binary release of the GCC front end for Linux/x86.
    +
    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.
    -
    cfrontend-x.y.i386-unknown-freebsd5.1.tar.gz
    -
    Binary release of the GCC front end for FreeBSD/x86.
    +
    llvm-gcc4-x.y-platform.tar.gz
    +
    Binary release of the llvm-gcc4 front end for a specific platform.
    -
    cfrontend-x.y.powerpc-apple-darwin7.6.0.tar.gz
    -
    Binary release of the GCC front end for MacOS X/PPC.
    +

    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.

    + @@ -619,9 +679,9 @@ follows:

    @@ -634,6 +694,11 @@ revision), you can specify a label. The following releases have the following labels:

      +
    • Release 1.9: RELEASE_19
    • +
    • Release 1.8: RELEASE_18
    • +
    • Release 1.7: RELEASE_17
    • +
    • Release 1.6: RELEASE_16
    • +
    • Release 1.5: RELEASE_15
    • Release 1.4: RELEASE_14
    • Release 1.3: RELEASE_13
    • Release 1.2: RELEASE_12
    • @@ -645,40 +710,18 @@ labels:

      you get it from the CVS repository:

         cd llvm/projects
      -  cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-test
      +  cvs -z3 -d :pserver:anon@llvm.org:/var/cvs/llvm co llvm-test
       

      By placing it in the llvm/projects, it will be automatically configured by the LLVM configure script as well as automatically updated when you run cvs update.

      -

      If you would like to get the GCC front end source code, you can also get it -from the CVS repository:

      - -
      -  cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-gcc
      -
      - -

      Please note that you must follow these -instructions to successfully build the LLVM GCC front-end.

      +

      If you would like to get the GCC front end source code, you can also get it +and build it yourself. Please follow these +instructions to successfully get and build the LLVM GCC front-end.

      - - - -
      - -

      If the main CVS server is overloaded or inaccessible, you can try one of -these user-hosted mirrors:

      - - -
      -
      Install the GCC Front End @@ -686,23 +729,27 @@ Inc.
      -

      Before configuring and compiling the LLVM suite, you need to extract the LLVM -GCC front end from the binary distribution. It is used for building the -bytecode libraries later used by the GCC front end for linking programs, and its -location must be specified when the LLVM suite is configured.

      +

      Before configuring and compiling the LLVM suite, you can optionally extract the +LLVM GCC front end from the binary distribution. It is used for running the +llvm-test testsuite and for compiling C/C++ programs. Note that you can optionally +build llvm-gcc yourself after building the +main LLVM repository.

      To install the GCC front end, do the following:

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

      Next, you will need to fix your system header files:

      - -

      cd cfrontend/platform
      - ./fixheaders

      +

      Once the binary is uncompressed, you should add a symlink for llvm-gcc and +llvm-g++ to some directory in your path. When you configure LLVM, it will +automatically detect llvm-gcc's presence (if it is in your path) enabling its +use in llvm-test. Note that you can always build or install llvm-gcc at any +pointer after building the main LLVM repository: just reconfigure llvm and +llvm-test will pick it up. +

      The binary versions of the GCC front end may not suit all of your needs. For example, the binary distribution may include an old version of a system header @@ -711,7 +758,7 @@ linked with libraries not available on your system.

      In cases like these, you may want to try building the GCC front end from source. This is -not for the faint of heart, so be forewarned.

      +much easier now than it was in the past.

      @@ -731,7 +778,7 @@ the Makefiles needed to begin building LLVM.

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

      - +
      @@ -767,19 +814,25 @@ script to configure the build system:

      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 the tclsh can be +
      Path to the tcl include directory under which tclsh can be found. Use this if you have multiple tcl installations on your machine and you want to use a specific one (8.x) for LLVM. LLVM only uses tcl for running the dejagnu based test suite in llvm/test. If you don't specify this - option, the LLVM configure script will search for tcl 8.4 and 8.3 releases. -

      + option, the LLVM configure script will search for the tcl 8.4 and 8.3 + releases. +

      --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-debug-runtime
      +
      + Enables debug symbols in the runtime libraries. The default is to strip + debug symbols from the runtime libraries.
      --enable-jit
      @@ -787,13 +840,28 @@ script to configure the build system:

      available on all platforms. The default is dependent on platform, so it is best to explicitly enable it if you want it. -

      +

      +
      --enable-targets=target-option
      +
      Controls which targets will be built and linked into llc. The default + value for target_options is "all" which builds and links all + available targets. The value "host-only" can be specified to build only a + native compiler (no cross-compiler targets available). The "native" target is + selected as the target of the build host. You can also specify a comma + separated list of target names that you want available in llc. The target + names use all lower case. The current set of targets is:
      + alpha, ia64, powerpc, skeleton, sparc, x86. +

      --enable-doxygen
      Look for the doxygen program and enable construction of doxygen based documentation from the source code. This is disabled by default because generating the documentation can take a long time and producess 100s of megabytes of output.
      +
      --with-udis86
      +
      LLVM can use external disassembler library for various purposes (now it's + used only for examining code produced by JIT). This option will enable usage + of udis86 x86 (both 32 and 64 + bits) disassembler library.

      To configure LLVM, follow these steps:

      @@ -802,12 +870,12 @@ script to configure the build system:

    • Change directory into the object root directory:
      cd OBJ_ROOT -

      +

    • Run the configure script located in the LLVM source tree:
      SRC_ROOT/configure --prefix=/install/path [other options] -

      +

      @@ -829,7 +897,7 @@ builds:

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

      +

      Release (Optimized) Builds
      @@ -838,7 +906,7 @@ 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. -

      +

      Profile Builds
      @@ -871,14 +939,14 @@ source code:

      Removes all files generated by the build. This includes object files, generated C/C++ files, libraries, and executables. -

      +

      gmake dist-clean
      Removes everything that gmake clean does, but also removes files generated by configure. It attempts to return the source tree to the original state in which it was shipped. -

      +

      gmake install
      @@ -886,15 +954,15 @@ source code:

      hierarchy under $PREFIX, specified with ./configure --prefix=[dir], which defaults to /usr/local. -

      - +

      +

      gmake -C runtime install-bytecode
      Assuming you built LLVM into $OBJDIR, when this command is run, it will install 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. -

      +

      Please see the Makefile Guide for further @@ -908,22 +976,27 @@ declaring variables on the command line. The following are some examples:

      gmake ENABLE_OPTIMIZED=1
      Perform a Release (Optimized) build. -

      +

      + +

      gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1 +
      + Perform a Release (Optimized) build without assertions enabled. +

      gmake ENABLE_PROFILING=1
      Perform a Profiling build. -

      +

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

      +

      gmake TOOL_VERBOSE=1
      Ask each tool invoked by the makefiles to print out what it is doing on the standard output. This also implies VERBOSE=1. -

      +

      Every directory in the LLVM object tree includes a Makefile to build @@ -933,6 +1006,51 @@ that directory that is out of date.

      + + + +
      +

      It is possible to cross-compile LLVM. That is, you can create LLVM + executables and libraries for a platform different than the one one which you + are compiling. To do this, a few additional steps are + required. 1 To cross-compile LLVM, use + these instructions:

      +
        +
      1. 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.
        • +
        +
      2. +
      3. Copy the TableGen binary to somewhere safe (out of your build tree). +
      4. +
      5. 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.
      6. +
      7. Put the saved TableGen executable into the + into $LLVM_OBJ_ROOT/{BUILD_TYPE}/bin directory (e.g. into + .../Release/bin for a Release build).
      8. +
      9. Build LLVM as usual.
      10. +
      +

      The result of such a build will produce executables that are not executable + on your build host (--build option) but can be executed on your compile host + (--host option).

      +

      Notes:

      +
      +
        +
      1. Cross-compiling was tested only with Linux as + build platform and Windows as host using mingw32 cross-compiler. Other + combinations have not been tested.
      2. +
      +
      +
      +
      The Location of LLVM Object Files @@ -969,7 +1087,7 @@ named after the build type:

      Libraries
      OBJ_ROOT/Debug/lib -

      +

      Release Builds
      @@ -979,7 +1097,7 @@ named after the build type:

      Libraries
      OBJ_ROOT/Release/lib -

      +

      Profile Builds
      @@ -1035,7 +1153,7 @@ Cummings for pointing this out!

      One useful source of information about the LLVM source base is the LLVM doxygen documentation available at http://llvm.cs.uiuc.edu/doxygen/. +href="http://llvm.org/doxygen/">http://llvm.org/doxygen/. The following is a brief introduction to code layout:

      @@ -1115,9 +1233,9 @@ different tools.

      llvm/lib/Target/
      This directory contains files that describe various target architectures - for code generation. For example, the llvm/lib/Target/SparcV9 - directory holds the Sparc machine description while - llvm/lib/Target/CBackend implements the LLVM-to-C converter
      + for code generation. For example, the llvm/lib/Target/X86 + directory holds the X86 machine description while + llvm/lib/Target/CBackend implements the LLVM-to-C converter.
      llvm/lib/CodeGen/
      This directory contains the major parts of the code generator: Instruction @@ -1183,8 +1301,8 @@ end to compile.

      module contains a comprehensive correctness, performance, and benchmarking test suite for LLVM. It is a separate CVS module because not every LLVM user is - interested in downloading or building such a comprehensive test. For further - details on this test suite, please see the + interested in downloading or building such a comprehensive test suite. For + further details on this test suite, please see the Testing Guide document.

      @@ -1199,11 +1317,6 @@ following is a brief introduction to the most important tools. More detailed information is in the Command Guide.

      -
      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 @@ -1220,8 +1333,8 @@ information is in the Command Guide.

      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 is new in 1.4 and considered experimental. It will be - fully supported in 1.5.
      + note that this tool, while functional, is still experimental and not feature + complete.
      llvm-ar
      The archiver produces an archive containing @@ -1237,12 +1350,10 @@ information is in the Command Guide.

      LLVM assembly.
      llvm-ld
      -
      llvm-ld is very similar to gccld and provides a general purpose - and extensible linker for LLVM. This is the linker invoked by llvmc. - It allows optimization modules to be loaded so that language specific - optimizations can be applied at link time. Please note that this tool is new - in LLVM 1.4 and still considered experimental. It will be fully supported in - LLVM 1.5.
      +
      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.
      llvm-link
      llvm-link, not surprisingly, links multiple LLVM modules into @@ -1260,48 +1371,26 @@ information is in the Command Guide.

      llc
      llc is the LLVM backend compiler, which - translates LLVM bytecode to a SPARC or x86 assembly file, or to C code (with + translates LLVM bytecode 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 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 - llvm-gcc 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 llvm-gcc 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 - llvm-gcc -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.
      -
      -
      -
      +
      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 + 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.
      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.
      +
      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.
      +
      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 + debugging analyses, or familiarizing yourself with what an analysis does.
      @@ -1314,16 +1403,11 @@ of the utilities are actually required as part of the build process because they are code generators for parts of LLVM infrastructure.

      -
      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'.

      + 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 @@ -1331,21 +1415,21 @@ are code generators for parts of LLVM infrastructure.

      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.

      + 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.

      + 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.

      - + tree.

      +

      llvmgrep
      This little tool performs an "egrep -H -n" on each source file in LLVM and passes to it a regular expression provided on llvmgrep's command @@ -1358,24 +1442,24 @@ are code generators for parts of LLVM infrastructure.

      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.

      + 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.

      + 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.

      + 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.

      + the README file in that directory.

      @@ -1396,6 +1480,22 @@ are code generators for parts of LLVM infrastructure.

      +
      +

      This section gives an example of using LLVM. llvm-gcc3 is now obsolete, +so we only include instructiosn for llvm-gcc4. +

      + +

      Note: The gcc4 frontend's invocation is considerably different +from the previous gcc3 frontend. In particular, the gcc4 frontend does not +create bytecode by default: gcc4 produces native code. As the example below illustrates, +the '--emit-llvm' flag is needed to produce LLVM bytecode output. For makefiles and +configure scripts, the CFLAGS variable needs '--emit-llvm' to produce bytecode +output.

      +
      + + + +
        @@ -1408,33 +1508,40 @@ are code generators for parts of LLVM infrastructure.

        } -
      1. Next, compile the C file into a LLVM bytecode file:

        +
      2. Next, compile the C file into a native executable:

        +

        % llvm-gcc hello.c -o hello

        -

        Note that you should have already built the tools and they have to be - in your path, at least gccas and gccld.

        +

        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).

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

        +

        % 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.

        -

        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. Note that - all LLVM optimizations are enabled by default, so there is no need for a - "-O3" switch.

      4. +

        Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments. +

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

        +
      6. Run the program in both forms. To run the program, use:

        % ./hello

        -

        or

        +

        and

        -

        % lli hello.bc

      7. +

        % lli hello.bc

        + +

        The second examples shows how to invoke the LLVM JIT, lli.

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

        -

        % llvm-dis < hello.bc | less

      9. +

        % llvm-dis < hello.bc | less

      10. Compile the program to native assembly using the LLC code generator:

        @@ -1448,12 +1555,17 @@ are code generators for parts of LLVM infrastructure.

      11. Execute the native code program:

        -

        % ./hello.native

      12. +

        % ./hello.native

        + +

        Note that using llvm-gcc to compile directly to native code (i.e. when + the -emit-llvm option is not present) does steps 6/7/8 for you.

        +
      +
      Common Problems @@ -1483,9 +1595,9 @@ if you want to write something up!). For more information about LLVM, check out:

      @@ -1502,7 +1614,7 @@ out:

      Chris Lattner
      Reid Spencer
      - The LLVM Compiler Infrastructure
      + The LLVM Compiler Infrastructure
      Last modified: $Date$
    • VariablePurpose
      CC