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 also contains a test suite that can be used
- to test the LLVM tools and the GCC front end.
+ 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 code into LLVM bytecode. Currently, the C 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.
+ 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.
+
+
+
+ The GCC front end is not very portable at the moment. If you want to get
+ it to work on another platform, you can always request
+ a copy of the source
+ and try to compile it on your platform.
+
-
+ Bison
+
There are some additional tools that you may want to have when working with
@@ -160,78 +236,39 @@
- - GNU Autoconf
-
- GNU M4
+
- GNU Autoconf
+
- GNU M4
If you want to make changes to the configure scripts, you will need
- GNU autoconf (2.53 or higher), and consequently, GNU M4 (version 1.4
+ 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 next section of this guide is meant to get
- you up and running with LLVM and to give you some basic information about
- the LLVM environment. The first subsection gives
- a short summary for those who are already familiar with the system and
- want to get started as quickly as possible.
+
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 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.
-
+
+
-
-
-
-
- Here's the short story for getting up and running quickly with LLVM:
-
- - Build the LLVM suite
-
- - Find the path to the CVS repository containing LLVM (we'll call this CVSROOTDIR).
-
- cd where-you-want-llvm-to-live
-
- cvs -d CVSROOTDIR checkout llvm
-
- cd llvm
-
- Run configure to configure the Makefiles and header files.
- Useful options include:
-
- - --with-objroot=directory
-
- Specify where object files should be placed during the build.
-
- - --with-llvmgccdir=directory
-
- Specify where the LLVM C frontend is going to be installed.
-
- - Set your LLVM_LIB_SEARCH_PATH environment variable.
-
- gmake -k |& tee gnumake.out
- # this is csh or tcsh syntax
-
-
-
- Build the LLVM C Front End (optional)
-
- - Create a directory for the object files to live.
-
- cd object file directory
-
- Run Pathname-to-where-the-source-code-lives/configure --prefix=LLVMGCCDIR to configure GCC.
-
- make bootstrap
-
- make install
-
-
-
- See Setting up your environment on tips to
- simplify working with the LLVM front-end and compiled tools. See the
- other sub-sections below for other useful details in working with LLVM,
- or go straight to Program Layout to learn about the
- layout of the source code tree.
-
@@ -243,44 +280,28 @@
each of these names with the appropriate pathname on your local system.
All these paths are absolute:
- - CVSROOTDIR
+
- SRC_ROOT
-
- This is the path for the CVS repository containing the LLVM source
- code. Ask the person responsible for your local LLVM installation to
- give you this path.
+ This is the top level directory of the LLVM source tree.
- OBJ_ROOT
-
- This is the top level directory for where the LLVM suite object files
- will be placed during the build.
+ 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 pathname to the location where the LLVM C Front End will
- be installed. Note that the C front end does not need to be installed
- during the LLVM suite build; you will just need to know where it will
- go for configuring the build system and running the test suite later.
+ This is the where the LLVM GCC Front End is installed.
- For the pre-built C front end binaries, the LLVMGCCDIR is
+ For the pre-built GCC front end binaries, the LLVMGCCDIR is
cfrontend/platform/llvm-gcc.
-
-
- GCCSRC
-
-
- This is the pathname of the directory where the LLVM C front end source
- code can be found.
-
-
-
- GCCOBJ
-
-
- This is the pathname of the directory where the LLVM C front end object
- code will be placed during the build. It can be safely removed once
- the build is complete.
-
+
@@ -292,40 +313,15 @@
- LLVM_LIB_SEARCH_PATH=LLVMGCCDIR/llvm-gcc/bytecode-libs
-
- This environment variable helps the LLVM C front end find bytecode
+ This environment variable helps the LLVM GCC front end find bytecode
libraries that it will need for compilation.
-
- PATH=${PATH}:OBJ_ROOT/llvm/tools/Debug
-
-
- Adding this directory to the end of your path will allow the
- compilation of the C front end to find the LLVM tools. The LLVM tools
- are needed for the C front end compile.
-
-
-
- CC=Pathname to your GCC compiler
-
-
- The GCC compiler that you want to use must be the first C compiler in
- your PATH. Otherwise, set this variable so that
- configure will use the GCC compiler that you want to use.
-
-
-
- CXX=Pathname to your GCC C++ compiler
+
- alias llvmgcc LLVMGCCDIR/llvm-gcc/bin/gcc
+
- alias llvmg++ LLVMGCCDIR/llvm-gcc/bin/g++
-
- The GCC compiler that you want to use must be the first C++ compiler in
- your PATH. Otherwise, set this variable so that
- configure will use the GCC compiler that you want to use.
-
-
-
- CVSROOT=CVSROOT
-
-
- This environment variable tells CVS where to find the CVS repository.
-
-
-
- alias llvmgcc LLVMGCCDIR/bin/llvm-gcc
-
-
- This alias allows you to use the LLVM C front end without putting it in
- your PATH or typing in its complete pathname.
+ 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.
@@ -334,42 +330,24 @@
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 four files. Each
+ 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 four files are the following:
+
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 C front end for Solaris/Sparc.
+
- This is the binary release of the GCC front end for Solaris/Sparc.
- cfrontend.x86.tar.gz
-
- This is the binary release of the C front end for Linux/x86.
-
-
-
- cfrontend-src.tar.gz
-
- This is the source code release of the C front end.
-
+
- This is the binary release of the GCC front end for Linux/x86.
-
- To unpack the files, take each one, unzip it, and then untar it. A fast
- way to do that is with the following:
-
-
- gunzip --stdout name of file | tar -xvf -
-
-
- For example, to extract the LLVM source code, use the following command:
-
-
- gunzip --stdout llvm.tar.gz | tar -xvf -
-
@@ -379,7 +357,9 @@
follows:
- cd where-you-want-llvm-to-live
-
- cvs -d CVSROOTDIR checkout llvm
+
- 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
@@ -387,11 +367,29 @@
test directories, and local copies of documentation files.
- Note that the C front end is not included in the CVS repository. You
- should have either downloaded the source, or better yet, downloaded the
- binary distribution for your platform.
+ Note that the GCC front end is not included in the CVS repository. You
+ should have downloaded the binary distribution for your platform.
+
+
+
+
+
+ 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:
+
+ - cd where-you-want-the-front-end-to-live
+
- gunzip --stdout cfrontend.platform.tar.gz | tar -xvf
+ -
+
+
@@ -399,32 +397,48 @@
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.
+ llvm/include/Config/config.h. It also populates OBJ_ROOT
+ with the Makefiles needed to build LLVM.
- The following environment variables are used by configure to
- configure Makefile.config:
+ The following environment variables are used by the configure
+ script to configure the build system:
-
- - CXX = Pathname of the C++ compiler to use.
-
- CC = Pathname of the C compiler to use.
-
+
+
+ | 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.
+ |
+
+
+
The following options can be used to set or enable LLVM specific options:
+
- - --with-objroot=OBJ_ROOT
-
-
- Path to the directory where
- object files, libraries, and executables should be placed.
- If this is set to ., then the object files will be placed
- within the source code tree. If left unspecified, the default value is
- ..
- (See the Section on
- The location for LLVM object files
- for more information.)
-
- --with-llvmgccdir=LLVMGCCDIR
-
Path to the location where the LLVM C front end binaries and
@@ -432,26 +446,51 @@
- --enable-optimized
-
- Enables optimized compilation (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 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:
+
+ - Change directory into the object root directory:
+
+ cd OBJ_ROOT
+
+
+
- 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 C front-end
- install, or LLVMGCCDIR/llvm-gcc/bytecode-libs. For example, one might
+ to the absolute path for the bytecode-libs subdirectory of the GCC front end
+ install, or LLVMGCCDIR/llvm-gcc/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 C front-end on our research machines.
+ version of the GCC front end on our research machines.
@@ -463,30 +502,33 @@
- Debug Builds
-
- These builds are the default. They compile the tools and libraries
- with debugging information.
+ 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. They compile the tools and libraries with GCC
- optimizer flags on and strip debugging information from the libraries
- and executables it generates.
+ 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 setting variables on the
- make command line.
+ 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 top level
- llvm directory and issuing the following command:
+ Once you have LLVM configured, you can build it by entering the
+ OBJ_ROOT directory and issuing the following command:
- make
+ gmake
If you have multiple processors in your machine, you may wish to use some
@@ -495,126 +537,81 @@
- make -j2
+ gmake -j2
- There are several other targets which are useful when working with the LLVM
+ There are several special targets which are useful when working with the LLVM
source code:
- - make clean
+
- gmake clean
-
Removes all files generated by the build. This includes object files,
generated C/C++ files, libraries, and executables.
-
- make distclean
+
- gmake distclean
-
- Removes everything that make clean does, but also removes
+ 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:
- - make ENABLE_OPTIMIZED=1
+
- gmake ENABLE_OPTIMIZED=1
-
Perform a Release (Optimized) build.
-
- make ENABLE_PROFILING=1
+
- gmake ENABLE_PROFILING=1
-
Perform a Profiling build.
-
- make VERBOSE=1
+
- gmake VERBOSE=1
-
- Print what make is doing on standard output.
+ Print what gmake is doing on standard output.
- Every directory in the LLVM source tree includes a Makefile to
+ 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 source tree and typing make should rebuild
+ inside the LLVM object tree and typing gmake should rebuild
anything in or below that directory that is out of date.
-
+
-
-
- This step is optional if you have the C front end binary distrubtion for
- your platform.
-
-
-
- Now that you have the LLVM Suite built, you can build the C front end. For
- those of you that have built GCC before, the process is very similar.
- Be forewarned, though: the build system for the C front end is not as
- polished as the rest of the LLVM code, so there will be many warnings and
- errors that you will need to ignore for now:
-
-
- - Ensure that OBJ_ROOT/llvm/tools/Debug is at the
- end of your PATH environment variable.
-
-
- cd GCCOBJ
-
-
- Configure the source code:
-
- - On Linux/x86, use
-
- - GCCSRC/configure --prefix=LLVMGCCDIR
- --enable-languages=c
-
-
- - On Solaris/Sparc, use
-
- - GCCSRC/configure --prefix=LLVMGCCDIR
- --enable-languages=c --target=sparcv9-sun-solaris2
-
-
-
- - make bootstrap
-
-
- The build will eventually fail. Don't worry; chances are good that
- everything that needed to build is built.
-
-
- make install
-
-
- At this point, you should have a working copy of the LLVM C front end
- installed in LLVMGCCDIR.
-
-
-
-
-
- The LLVM build system sends most output files generated during the build
- into the directory defined by the variable OBJ_ROOT in
- llvm/Makefile.config, which is set by the --with-objroot
- option in configure. This can be either just your normal LLVM
- source tree or some other directory writable by you. You may wish to put
- object files on a different filesystem either to keep them from being backed
- up or to speed up local builds.
-
+ 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.
- If OBJ_ROOT is specified, then the build system will create a
- directory tree underneath it that resembles the source code's pathname
- relative to your home directory.
-
+ This is accomplished in the typical autoconf manner:
+
+ - Change directory to where the LLVM object files should live:
+
+ cd OBJ_ROOT
-
- For example, suppose that OBJ_ROOT is set to /tmp and the
- LLVM suite source code is located in /usr/home/joe/src/llvm, where
- /usr/home/joe is the home directory of a user named Joe. Then,
- the object files will be placed in /tmp/src/llvm.
-
+ - Run the configure script found in the LLVM source directory:
+
+ SRC_ROOT/configure
+
The LLVM build will place files underneath OBJ_ROOT in directories
@@ -626,9 +623,9 @@
- Tools
-
- OBJ_ROOT/llvm/tools/Debug
+
- OBJ_ROOT/tools/Debug
- Libraries
-
- OBJ_ROOT/llvm/lib/Debug
+
- OBJ_ROOT/lib/Debug
@@ -636,9 +633,9 @@
- Tools
-
- OBJ_ROOT/llvm/tools/Release
+
- OBJ_ROOT/tools/Release
- Libraries
-
- OBJ_ROOT/llvm/lib/Release
+
- OBJ_ROOT/lib/Release
@@ -646,9 +643,9 @@
- Tools
-
- OBJ_ROOT/llvm/tools/Profile
+
- OBJ_ROOT/tools/Profile
- Libraries
-
- OBJ_ROOT/llvm/lib/Profile
+
- OBJ_ROOT/lib/Profile
@@ -656,13 +653,15 @@
+
- One useful source of information about the LLVM source base is the LLVM
+ 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:
-
+ href="http://llvm.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/.
+ The following is a brief introduction to code layout:
+
@@ -683,18 +682,18 @@
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,
- Reoptimizer, Target, Transforms, etc...
+ Target, Transforms, etc...
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.
+ library store their header files here.
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.
+ automatically take care of the conditional #includes that the
+ configure script generates.
@@ -702,7 +701,7 @@
This directory contains most of the source files of the LLVM system. In
- LLVM almost all
+ LLVM, almost all
code exists in libraries, making it very easy to share code among the
different tools.
@@ -727,8 +726,7 @@
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
- Invarient Code Motion, Dead Global Elimination, Pool Allocation, and many
- others...
+ 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,
@@ -739,20 +737,34 @@
of the code generator: Instruction Selector, Instruction Scheduling, and
Register Allocation.
- llvm/lib/Reoptimizer/ This directory holds code related
- to the runtime reoptimizer framework that is currently under development.
-
llvm/lib/Support/ This directory contains the source code
that corresponds to the header files located in
llvm/include/Support/.
+
+
+
+
+
+ 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.
+
+
This directory contains regression tests and source code that is used to
- test the LLVM infrastructure...
+ test the LLVM infrastructure.
+
@@ -764,50 +776,70 @@
following is a brief introduction to the most important tools.
- - as
- The assembler transforms the human readable
+
-
+
+
- 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.
-
- 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-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 is also has debugger and tracing
- modes (entered by specifying -debug or -trace on the
- command line, respectively). 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.
+ 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
+
- 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
+ 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.
+ 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
+ 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.
@@ -818,16 +850,81 @@
command is a good way to get a list of the program transformations
available in LLVM.
-
-
- 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.
+
+
+
+
+
+ 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.
+
-
+
-
+
+
@@ -859,10 +956,10 @@
% lli hello.bc
- - Use the dis utility to take a look at the LLVM assembly
+
- Use the llvm-dis utility to take a look at the LLVM assembly
code:
- % dis < hello.bc | less
+ % llvm-dis < hello.bc | less
- Compile the program to native Sparc assembly using the code
generator (assuming you are currently on a Sparc system):
@@ -881,59 +978,19 @@
-
+
+
- Below are common problems and their remedies:
-
-
- - When I run configure, it finds the wrong C compiler.
-
-
- The configure script attempts to locate first gcc and
- then cc, unless it finds compiler paths set in CC and
- CXX for the C and C++ compiler, respectively.
-
- If configure finds the wrong compiler, either adjust your
- PATH environment variable or set CC and CXX
- explicitly.
-
-
- - I compile the code, and I get some error about /localhome.
-
-
- There are several possible causes for this. The first is that you
- didn't set a pathname properly when using configure, and it
- defaulted to a pathname that we use on our research machines.
-
- Another possibility is that we hardcoded a path in our Makefiles. If
- you see this, please email the LLVM bug mailing list with the name of
- the offending Makefile and a description of what is wrong with it.
-
- - The configure script finds the right C compiler, but it
- uses the LLVM linker from a previous build. What do I do?
-
-
- The configure script uses the PATH to find
- executables, so if it's grabbing the wrong linker/assembler/etc, there
- are two ways to fix it:
-
- - Adjust your PATH environment variable so that the
- correct program appears first in the PATH. This may work,
- but may not be convenient when you want them first in your
- path for other work.
-
-
- - Run configure with an alternative PATH that
- is correct. In a Borne compatible shell, the syntax would be:
-
- PATH= ./configure ...
-
- This is still somewhat inconvenient, but it allows
- configure to do its work without having to adjust your
- PATH permanently.
-
-
+ 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
@@ -956,7 +1013,7 @@
-Last modified: Tue Jun 3 22:06:43 CDT 2003
+Last modified: Mon Aug 11 13:52:22 CDT 2003
|