@@ -493,8 +504,8 @@ 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, 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
+successfully with them (however, see important notes 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
@@ -506,24 +517,79 @@ of GCC you are using.
problems in the STL that effectively prevent it from compiling LLVM.
-
GCC 3.2.2: This version of GCC fails to compile LLVM.
+
GCC 3.2.2 and 3.2.3: These versions of GCC fails to compile LLVM with
+a bogus template error. This was fixed in later GCCs.
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
+ 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 3.4.0 on linux/x86 (32-bit): GCC miscompiles portions of the
+ code generator, causing an infinite loop in the llvm-gcc build when built
+ with optimizations enabled (i.e. a release build).
+
GCC 3.4.2 on linux/x86 (32-bit): GCC miscompiles portions of the
+ code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
+ correctly compiles LLVM at -O2. A work around is to build release LLVM
+ builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."
+
GCC 3.4.x on X86-64/amd64: GCC
+ miscompiles portions of LLVM.
+
GCC 3.4.4 (CodeSourcery ARM 2005q3-2): this compiler miscompiles LLVM
+ when building with optimizations enabled. It appears to work with
+ "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1" or build a debug
+ build.
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.
+
GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian: Appears
+to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining
+about symbols remaining in the table on destruction.
+
GCC 4.1.2 20071124 (Red Hat 4.1.2-42): Suffers from the same symptoms
+as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).
+
Cygwin GCC 4.3.2 20080827 (beta) 2:
+ Users reported various problems related
+ with link errors when using this GCC version.
+
Debian GCC 4.3.2 on X86: Crashes building some files in LLVM 2.6.
+
GCC 4.3.3 (Debian 4.3.3-10) on ARM: Miscompiles parts of LLVM 2.6
+when optimizations are turned on. The symptom is an infinite loop in
+FoldingSetImpl::RemoveNode while running the code generator.
+
GCC 4.3.5 and GCC 4.4.5 on ARM: These can miscompile value >>
+1 even at -O0. A test failure in test/Assembler/alignstack.ll is
+one symptom of the problem.
+
GNU ld 2.16.X. Some 2.16.X versions of the ld linker will produce very
+long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
+defined in a discarded section. You can safely ignore these messages as they are
+erroneous and the linkage is correct. These messages disappear using ld
+2.17.
+
+
GNU binutils 2.17: Binutils 2.17 contains a bug which
+causes huge link times (minutes instead of seconds) when building LLVM. We
+recommend upgrading to a newer version (2.17.50.0.4 or later).
+
+
GNU Binutils 2.19.1 Gold: This version of Gold contained
+a bug
+which causes intermittent failures when building LLVM with position independent
+code. The symptom is an error about cyclic dependencies. We recommend
+upgrading to a newer version of Gold.
+
@@ -564,21 +630,21 @@ All these paths are absolute:
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.
@@ -595,11 +661,11 @@ In order to compile and use LLVM, you may need to set some environment
variables.
- - LLVM_LIB_SEARCH_PATH=/path/to/your/bytecode/libs
+ - LLVM_LIB_SEARCH_PATH=/path/to/your/bitcode/libs
- [Optional] This environment variable helps LLVM linking tools find the
- locations of your bytecode libraries. It is provided only as a
+ locations of your bitcode libraries. It is provided only as a
convenience since you can specify the paths using the -L options of the
- tools and the C/C++ front-end will automatically use the bytecode files
+ tools and the C/C++ front-end will automatically use the bitcode files
installed in its
lib directory.
@@ -624,62 +690,62 @@ compressed with the gzip program.
The files are as follows, with x.y marking the version number:
- llvm-x.y.tar.gz
- - Source release for the LLVM libraries and tools.
+ - Source release for the LLVM libraries and tools.
- llvm-test-x.y.tar.gz
- - Source release for the LLVM test suite.
+ - Source release for the LLVM test-suite.
- - cfrontend-x.y.source.tar.gz
- - Source release of the GCC front end.
+ - llvm-gcc-4.2-x.y.source.tar.gz
+ - Source release of the llvm-gcc-4.2 front end. See README.LLVM in the root
+ directory for build instructions.
- - cfrontend-x.y.i686-redhat-linux-gnu.tar.gz
- - Binary release of the GCC front end for Linux/x86.
+ - llvm-gcc-4.2-x.y-platform.tar.gz
+ - Binary release of the llvm-gcc-4.2 front end for a specific platform.
- - llvm-gcc4-x.y.source.tar.gz
- - Source release of the llvm-gcc4 front end. See README.LLVM in the root
- directory for build instructions.
-
- - llvm-gcc4-x.y.powerpc-apple-darwin8.6.0.tar.gz
- - Binary release of the llvm-gcc4 front end for MacOS X/PowerPC.
-
- - llvm-gcc4-x.y.i686-apple-darwin8.6.1.tar.gz
- - Binary release of the llvm-gcc4 front end for MacOS X/X86.
-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.
-
-
-
If you have access to our CVS repository, you can get a fresh copy of
-the entire source code. All you need to do is check it out from CVS as
+
If you have access to our Subversion repository, you can get a fresh copy of
+the entire source code. All you need to do is check it out from Subversion as
follows:
-- cd where-you-want-llvm-to-live
-
- cvs -d :pserver:anon@llvm-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
+
- cd where-you-want-llvm-to-live
+ - Read-Only: svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm
+ - Read-Write:svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
+ llvm
+
This will create an 'llvm' directory in the current
directory and fully populate it with the LLVM source code, Makefiles,
test directories, and local copies of documentation files.
If you want to get a specific release (as opposed to the most recent
-revision), you can specify a label. The following releases have the following
-labels:
+revision), you can checkout it from the '
tags' directory (instead of
+'
trunk'). The following releases are located in the following
+subdirectories of the '
tags' directory:
+- Release 2.8: RELEASE_28
+- Release 2.7: RELEASE_27
+- Release 2.6: RELEASE_26
+- Release 2.5: RELEASE_25
+- Release 2.4: RELEASE_24
+- Release 2.3: RELEASE_23
+- Release 2.2: RELEASE_22
+- Release 2.1: RELEASE_21
+- Release 2.0: RELEASE_20
+- Release 1.9: RELEASE_19
+- Release 1.8: RELEASE_18
- Release 1.7: RELEASE_17
- Release 1.6: RELEASE_16
- Release 1.5: RELEASE_15
@@ -691,23 +757,22 @@ labels:
If you would like to get the LLVM test suite (a separate package as of 1.4),
-you get it from the CVS repository:
+you get it from the Subversion repository:
+
+
- cd llvm/projects
- cvs -z3 -d :pserver:anon@llvm-cvs.cs.uiuc.edu:/var/cvs/llvm co llvm-test
+% cd llvm/projects
+% svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite
+
+
By placing it in the llvm/projects, it will be automatically
configured by the LLVM configure script as well as automatically updated when
-you run cvs update.
-
-
If you would like to get the GCC 3.4 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
-
+you run
svn update.
-
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.
@@ -718,32 +783,66 @@ instructions to successfully build the LLVM 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.
+
Before configuring and compiling the LLVM suite (or if you want to use just the LLVM
+GCC front end) you can optionally extract the front end from the binary distribution.
+It is used for running the LLVM test-suite and for compiling C/C++ programs. Note that
+you can optionally build llvm-gcc yourself after building the
+main LLVM repository.
-
To install the GCC front end, do the following:
+
To install the GCC front end, do the following (on Windows, use an archival tool
+like 7-zip that understands gzipped tars):
- cd where-you-want-the-front-end-to-live
- - gunzip --stdout cfrontend-version.platform.tar.gz | tar -xvf
+
- gunzip --stdout llvm-gcc-4.2-version-platform.tar.gz | tar -xvf
-
-
Next, you will need to fix your system header files:
+
Once the binary is uncompressed, if you're using a *nix-based system, add a symlink for
+llvm-gcc and llvm-g++ to some directory in your path. If you're using a
+Windows-based system, add the bin subdirectory of your front end installation directory
+to your PATH environment variable. For example, if you uncompressed the binary to
+c:\llvm-gcc, add c:\llvm-gcc\bin to your PATH.
+
+
If you now want to build LLVM from source, when you configure LLVM, it will
+automatically detect llvm-gcc's presence (if it is in your path) enabling its
+use in test-suite. Note that you can always build or install llvm-gcc at any
+point after building the main LLVM repository: just reconfigure llvm and
+test-suite will pick it up.
+
-
cd cfrontend/platform
- ./fixheaders
+
As a convenience for Windows users, the front end binaries for MinGW/x86 include
+versions of the required w32api and mingw-runtime binaries. The last remaining step for
+Windows users is to simply uncompress the binary binutils package from
+MinGW into your front end installation directory. While the
+front end installation steps are not quite the same as a typical manual MinGW installation,
+they should be similar enough to those who have previously installed MinGW on Windows systems.
-
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.
+
To install binutils on Windows:
-
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.
+
+ - download GNU Binutils from MinGW Downloads
+ - cd where-you-uncompressed-the-front-end
+ - uncompress archived binutils directories (not the tar file) into the current directory
+
+
+
The binary versions of the LLVM GCC front end may not suit all of your needs. For
+example, the binary distribution may include an old version of a system header
+file, not "fix" a header file that needs to be fixed for GCC, or it may be linked with
+libraries not available on your system. In cases like these, you may want to try
+building the GCC front end from source. Thankfully,
+this is much easier now than it was in the past.
+
+
We also do not currently support updating of the GCC front end by manually overlaying
+newer versions of the w32api and mingw-runtime binary packages that may become available
+from MinGW. At this time, it's best to think of the MinGW LLVM GCC front end binary as
+a self-contained convenience package that requires Windows users to simply download and
+uncompress the GNU Binutils binary package from the MinGW project.
+
+
Regardless of your platform, if you discover that installing the LLVM GCC front end
+binaries is not as easy as previously described, or you would like to suggest improvements,
+please let us know how you would like to see things improved by dropping us a note on our
+mailing list.
@@ -754,7 +853,8 @@ not for the faint of heart, so be forewarned.
-
Once checked out from the CVS repository, the LLVM suite source code must be
+
Once checked out from the Subversion repository, the LLVM suite source
+ code must be
configured via the configure script. This script sets variables in the
various *.in files, most notably llvm/Makefile.config and
llvm/include/Config/config.h. It also populates OBJ_ROOT with
@@ -763,7 +863,7 @@ the Makefiles needed to begin building LLVM.
The following environment variables are used by the configure
script to configure the build system:
-
+
Variable | Purpose |
CC |
@@ -796,7 +896,7 @@ script to configure the build system:
will fail as these libraries require llvm-gcc and llvm-g++. See
Install the GCC Front End for details on installing
the C/C++ Front End. See
- Bootstrapping the LLVM C/C++ Front-End
+ Bootstrapping the LLVM C/C++ Front-End
for details on building the C/C++ Front End.
--with-tclinclude
Path to the tcl include directory under which tclsh can be
@@ -805,14 +905,16 @@ script to configure the build system:
dejagnu based test suite in llvm/test. If you don't specify this
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).
-
+ Enables optimized compilation (debugging symbols are removed
+ and GCC optimization flags are enabled). Note that this is the default
+ setting if you are using the LLVM distribution. The default behavior
+ of an Subversion checkout is to use an unoptimized build (also known as a
+ debug build).
+
--enable-debug-runtime
@@ -825,7 +927,7 @@ 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
@@ -834,28 +936,34 @@ script to configure the build system:
native compiler (no cross-compiler targets available). The "native" target is
selected as the target of the build host. You can also specify a comma
separated list of target names that you want available in llc. The target
- names use all lower case. The current set of targets is:
+ names use all lower case. The current set of targets is:
alpha, ia64, powerpc, skeleton, sparc, x86.
-
+
--enable-doxygen
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:
- - Change directory into the object root directory:
-
- cd OBJ_ROOT
-
+
Change directory into the object root directory:
- - Run the configure script located in the LLVM source tree:
-
- SRC_ROOT/configure --prefix=/install/path [other options]
-
+
+
+ Run the configure script located in the LLVM source
+ tree:
+
+
+
% SRC_ROOT/configure --prefix=/install/path [other options]
+
@@ -873,11 +981,13 @@ builds:
- Debug Builds
-
- These builds are the default when one types gmake (unless the
- --enable-optimized option was used during configuration). The
- build system will compile the tools and libraries with debugging
- information.
-
+ These builds are the default when one is using an Subversion checkout and
+ types gmake (unless the --enable-optimized option was
+ used during configuration). The build system will compile the tools and
+ libraries with debugging information. To get a Debug Build using the
+ LLVM distribution the --disable-optimized option must be passed
+ to configure.
+
- Release (Optimized) Builds
-
@@ -886,7 +996,8 @@ builds:
gmake command line. For these builds, the build system will
compile the tools and libraries with GCC optimizations enabled and strip
debugging information from the libraries and executables it generates.
-
+ Note that Release Builds are default when using an LLVM distribution.
+
- Profile Builds
-
@@ -899,7 +1010,7 @@ builds:
Once you have LLVM configured, you can build it by entering the
OBJ_ROOT directory and issuing the following command:
-gmake
+
If the build fails, please check here to see if you
are using a version of GCC that is known not to compile LLVM.
@@ -909,7 +1020,7 @@ If you have multiple processors in your machine, you may wish to use some of
the parallel build options provided by GNU Make. For example, you could use the
command:
-gmake -j2
+
There are several special targets which are useful when working with the LLVM
source code:
@@ -919,14 +1030,14 @@ 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
-
@@ -934,15 +1045,15 @@ 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,
+ install bitcode libraries into the GCC front end's bitcode library
+ directory. If you need to update your bitcode libraries,
this is the target to use once you've built them.
-
+
Please see the Makefile Guide for further
@@ -956,27 +1067,32 @@ 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_OPTIMIZED=0
+
+ Perform a Debug build.
+
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
@@ -986,6 +1102,24 @@ that directory that is out of date.
+
+
+
+
+
It is possible to cross-compile LLVM itself. That is, you can create LLVM
+ executables and libraries to be hosted on a platform different from the
+ platform where they are build (a Canadian Cross build). To configure a
+ cross-compile, supply the configure script with --build and
+ --host options that are different. The values of these options must
+ be legal target triples that your GCC compiler supports.
+
+
The result of such a build is executables that are not runnable on
+ on the build host (--build option) but can be executed on the compile host
+ (--host option).
+
+
The Location of LLVM Object Files
@@ -1002,27 +1136,27 @@ platforms or configurations using the same source tree.
The LLVM build will place files underneath OBJ_ROOT in directories
named after the build type:
- - Debug Builds
+
- Debug Builds with assertions enabled (the default)
-
- Tools
-
- OBJ_ROOT/Debug/bin
+
- OBJ_ROOT/Debug+Asserts/bin
- Libraries
-
- OBJ_ROOT/Debug/lib
+
- OBJ_ROOT/Debug+Asserts/lib
-
+
- Release Builds
-
@@ -1032,7 +1166,7 @@ named after the build type:
- Libraries
- OBJ_ROOT/Release/lib
-
+
Profile Builds
@@ -1055,28 +1189,32 @@ named after the build type:
If you're running on a Linux system that supports the "
- binfmt_misc"
+href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc"
module, and you have root access on the system, you can set your system up to
-execute LLVM bytecode files directly. To do this, use commands like this (the
+execute LLVM bitcode files directly. To do this, use commands like this (the
first command may not be required if you are already using the module):
- $ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
- $ echo ':llvm:M::llvm::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
- $ chmod u+x hello.bc (if needed)
- $ ./hello.bc
+$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
+$ echo ':llvm:M::BC::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
+$ chmod u+x hello.bc (if needed)
+$ ./hello.bc
-This allows you to execute LLVM bytecode files directly. Thanks to Jack
-Cummings for pointing this out!
+This allows you to execute LLVM bitcode files directly. On Debian, you
+can also use this command instead of the 'echo' command above:
+
+
+$ sudo update-binfmts --install llvm /path/to/lli --magic 'BC'
+
+
@@ -1093,13 +1231,6 @@ The following is a brief introduction to code layout:
-
-
-
-
Every directory checked out of CVS will contain a CVS directory; for
-the most part these can just be ignored.
-
-
@@ -1152,8 +1283,8 @@ different
tools.
This directory holds the source code for the LLVM assembly language parser
library.
-
llvm/lib/ByteCode/
-
This directory holds code for reading and write LLVM bytecode.
+
llvm/lib/BitCode/
+
This directory holds code for reading and write LLVM bitcode.
llvm/lib/Analysis/This directory contains a variety of
different program analyses, such as Dominator Information, Call Graphs,
@@ -1182,7 +1313,7 @@ different tools.
source code locations at which the program is executing.
llvm/lib/ExecutionEngine/
-
This directory contains libraries for executing LLVM bytecode directly
+ This directory contains libraries for executing LLVM bitcode directly
at runtime in both interpreted and JIT compiled fashions.
llvm/lib/Support/
@@ -1202,15 +1333,14 @@ different
tools.
This directory contains projects that are not strictly part of LLVM but are
shipped with LLVM. This is also the directory where you should create your own
LLVM-based projects. See llvm/projects/sample for an example of how
- to set up your own project. See llvm/projects/Stacker for a fully
- functional example of a compiler front end.
+ to set up your own project.
-
This directory contains libraries which are compiled into LLVM bytecode and
+
This directory contains libraries which are compiled into LLVM bitcode and
used when linking programs with the GCC front end. Most of these libraries are
skeleton versions of real libraries; for example, libc is a stripped down
version of glibc.
@@ -1229,13 +1359,16 @@ end to compile.
-
+
-
This is not a directory in the normal llvm module; it is a separate CVS
- module that must be checked out (usually to projects/llvm-test). This
+
This is not a directory in the normal llvm module; it is a separate
+ Subversion
+ module that must be checked out (usually to projects/test-suite).
+ This
module contains a comprehensive correctness, performance, and benchmarking
test
- suite for LLVM. It is a separate CVS module because not every LLVM user is
+ suite for LLVM. It is a separate Subversion module because not every LLVM
+ user is
interested in downloading or building such a comprehensive test suite. For
further details on this test suite, please see the
Testing Guide document.
@@ -1247,16 +1380,11 @@ end to compile.
The tools directory contains the executables built out of the
libraries above, which form the main part of the user interface. You can
-always get help for a tool by typing tool_name --help. The
+always get help for a tool by typing tool_name -help. The
following is a brief introduction to the most important tools. More detailed
information is in the Command Guide.
- - 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
@@ -1271,30 +1399,29 @@ information is in the Command Guide.
be configured to utilize both LLVM and non-LLVM compilation tools to enable
pre-processing, translation, optimization, assembly, and linking of programs
all from one command line. llvmc also takes care of processing the
- dependent libraries found in bytecode. This reduces the need to get the
+ dependent libraries found in bitcode. This reduces the need to get the
traditional -l<name> options right on the command line. Please
note that this tool, while functional, is still experimental and not feature
complete.
- llvm-ar
- The archiver produces an archive containing
- the given LLVM bytecode files, optionally with an index for faster
+ the given LLVM bitcode files, optionally with an index for faster
lookup.
- llvm-as
- The assembler transforms the human readable LLVM assembly to LLVM
- bytecode.
+ bitcode.
- llvm-dis
- - The disassembler transforms the LLVM bytecode to human readable
+
- The disassembler transforms the LLVM bitcode to human readable
LLVM assembly.
- llvm-ld
- - llvm-ld is 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. This tool is considered
- experimental.
+ - llvm-ld is a general purpose and extensible linker for LLVM.
+ This is the linker invoked by llvmc. It performs standard link time
+ optimizations and allows optimization modules to be loaded and run so that
+ language specific optimizations can be applied at link time.
- llvm-link
- llvm-link, not surprisingly, links multiple LLVM modules into
@@ -1302,57 +1429,33 @@ information is in the Command Guide.
- lli
- lli is the LLVM interpreter, which
- can directly execute LLVM bytecode (although very slowly...). In addition
- to a simple interpreter, lli also has a tracing mode (entered by
- specifying -trace on the command line). Finally, for
- architectures that support it (currently x86, Sparc, and PowerPC), by default,
- lli will function as a Just-In-Time compiler (if the
- functionality was compiled in), and will execute the code much
- faster than the interpreter.
+ can directly execute LLVM bitcode (although very slowly...). For architectures
+ that support it (currently x86, Sparc, and PowerPC), by default, lli
+ will function as a Just-In-Time compiler (if the functionality was compiled
+ in), and will execute the code much faster than the interpreter.
- llc
- llc is the LLVM backend compiler, which
- translates LLVM bytecode to a native code assembly file or to C code (with
+ translates LLVM bitcode to a native code assembly file or to C code (with
the -march=c option).
- llvm-gcc
- - llvm-gcc is a GCC-based C frontend
- that has been retargeted to 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 available as a separate CVS module.
-
-
- - 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
+ bitcode or assembly (with the -emit-llvm option) instead of the
+ usual machine code output. It works just like any other GCC compiler,
+ taking the typical -c, -S, -E, -o options that are typically used.
+ Additionally, the the source code for llvm-gcc is available as a
+ separate Subversion 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 bitcode, applies a series of LLVM to LLVM
+ transformations (which are specified on the command line), and then outputs
+ the resultant bitcode. The 'opt -help' command is a good way to
+ get a list of the program transformations available in LLVM.
+ - opt can also be used to run a specific analysis on an input
+ LLVM bitcode file and print out the results. It is primarily useful for
+ debugging analyses, or familiarizing yourself with what an analysis does.
@@ -1369,29 +1472,21 @@ are code generators for parts of LLVM infrastructure.
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.
+ manual, run `perldoc codegen-diff'.
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
@@ -1404,102 +1499,133 @@ 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
+ NewNightlyTest.pl and
NightlyTestTemplate.html These files are used in a
cron script to generate nightly status reports of the functionality of
tools, and the results can be seen by following the appropriate link on
- 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.
-
-
-
-
This directory contains build scripts and project files for use with
- Visual C++. This allows developers on Windows to build LLVM without the need
- for Cygwin. The contents of this directory should be considered experimental
- at this time.
-
-
+
+
This section gives an example of using LLVM. llvm-gcc3 is now obsolete,
+so we only include instructions for llvm-gcc4.
+
+
+
Note: The gcc4 frontend's invocation is considerably different
+from the previous gcc3 frontend. In particular, the gcc4 frontend does not
+create bitcode by default: gcc4 produces native code. As the example below illustrates,
+the '--emit-llvm' flag is needed to produce LLVM bitcode output. For makefiles and
+configure scripts, the CFLAGS variable needs '--emit-llvm' to produce bitcode
+output.
+
+
+
+
+
- - First, create a simple C file, name it 'hello.c':
-
- #include <stdio.h>
- int main() {
- printf("hello world\n");
- return 0;
- }
-
-
- Next, compile the C file into a LLVM bytecode file:
- % 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.
-
- 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.
-
- Run the program. To make sure the program ran, execute one of the
- following commands:
+ First, create a simple C file, name it 'hello.c':
+
+
+
+#include <stdio.h>
+
+int main() {
+ printf("hello world\n");
+ return 0;
+}
+
+
+ Next, compile the C file into a native executable:
+
+ % llvm-gcc hello.c -o hello
+
+ 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).
+
+ Next, compile the C file into a LLVM bitcode 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 bitcode file.
+
+ Unlike llvm-gcc3, llvm-gcc4 correctly responds to -O[0123] arguments.
+
+
+ Run the program in both forms. To run the program, use:
- % ./hello
+
- or
+ and
+
+
- % lli hello.bc
+ The second examples shows how to invoke the LLVM JIT, lli.
Use the llvm-dis utility to take a look at the LLVM assembly
code:
- % llvm-dis < hello.bc | less
+
+
llvm-dis < hello.bc | less
+
Compile the program to native assembly using the LLC code
generator:
- % llc hello.bc -o hello.s
+ % llc hello.bc -o hello.s
Assemble the native assembly language file into a program:
- Solaris:% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
- Others:% gcc hello.s -o hello.native
+
+
+Solaris: % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
+
+Others: % gcc hello.s -o hello.native
+
+
Execute the native code program:
- % ./hello.native
+
+
+ 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
@@ -1522,7 +1648,7 @@ Asked Questions page.
-
This document is just an introduction to how to use LLVM to do
+
This document is just an introduction on how to use LLVM to do
some simple things... there are many more interesting and complicated things
that you can do that aren't documented here (but we'll gladly accept a patch
if you want to write something up!). For more information about LLVM, check
@@ -1542,9 +1668,9 @@ out:
+ src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS">
+ src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01">
Chris Lattner
Reid Spencer