-*- mode: Text -*-

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C-Reduce

Before compiling C-Reduce yourself, you might want to see if your OS
comes with a precompiled package for C-Reduce.  Ubuntu, Debian, Gentoo,
and Mac OS X (Homebrew) all do.  For example, on OS X:

$ brew install creduce

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Prereqs:

C-Reduce is written in Perl, C++, and C.  To compile and run C-Reduce,
you will need a development environment that supports these languages.
C-Reduce's build system requires CMake or GNU Make (*not* BSD Make).

Beyond the basic compile/build tools, C-Reduce depends on a set of
third-party software packages, including LLVM.

On Ubuntu or Mint, the prerequisites other than LLVM can be installed
like this:

  sudo apt-get install \
    libexporter-lite-perl libfile-which-perl libgetopt-tabular-perl \
    libregexp-common-perl flex build-essential \
    zlib1g-dev

On OS X, Perlbrew provides an easy and flexible way to get Perl and
Perl modules installed:

  http://perlbrew.pl/

On FreeBSD 10.3 and 11.1, the prerequisites can be installed like this:

  sudo pkg install \
    llvm60 \
    p5-Exporter-Lite p5-File-Which p5-Getopt-Tabular p5-Regexp-Common \
    flex

Otherwise, install these packages either manually or using the package
manager:

Flex:
  http://flex.sourceforge.net/

LLVM/Clang 6.0.0:
  http://llvm.org/releases/download.html#6.0.0
  (No need to compile it: the appropriate "Clang binaries" package is
  all you need.  If you use one of the binary packages, you may need to
  install additional packages that the binary package depends on.  For
  example, the "Clang for x86_64 Ubuntu 14.04" binary package depends
  on "libtinfo5".  You may need to install this, e.g.:
  "sudo apt-get install libtinfo-dev".)

Perl modules:
  Exporter::Lite
  File::Which
  Getopt::Tabular
  Regexp::Common

For example, (perhaps as root):
  cpan -i 'Exporter::Lite'
  cpan -i 'File::Which'
  cpan -i 'Getopt::Tabular'
  cpan -i 'Regexp::Common'

zlib:
  http://www.zlib.net/

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Optional prereqs:

Term::ReadKey is optional; C-Reduce will use it if it is installed.

On Ubuntu:

  sudo apt-get install libterm-readkey-perl

On OS X (with Homebrew + Perlbrew installed):

  cpan -i 'Term::ReadKey'

On FreeBSD 10.3:

  sudo pkg install p5-Term-ReadKey

Otherwise, install the packages either manually or using the package
manager.

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Building and installing C-Reduce:

You can configure, build, and install C-Reduce with the provided
`configure' script or with CMake.

* Preface: If in Doubt, Compile With `clang++'

If you encounter weird C++ link-time errors while trying to compile
C-Reduce (in particular, while compiling its internal `clang_delta'
tool), please try compiling with `clang++'.

We have encountered link-time problems while trying to compile
C-Reduce with GCC 5.* and the precompiled LLVM binaries available
from <http://llvm.org/releases/download.html>.  If you encounter
similar problems, we strongly suggest that you use Clang instead of
GCC to compile C-Reduce and its internal tools.

If you are curious, for some discussion of this issue, see:
<https://github.com/csmith-project/creduce/issues/101>
<https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html>

* The `configure' Way

From either the source directory or a build directory:

  [source-path/]configure [options]
  make
  make install

The `configure' script was generated by GNU Autoconf, and therefore
accepts the usual options for naming the installation directories,
choosing the compilers you want to use, and so on.  `configure --help'
summarizes the command-line options.

If LLVM/Clang is not in your search path, you can tell the `configure'
script where to find LLVM/Clang:

  # Use the LLVM/Clang tree rooted at /opt/llvm
  configure --with-llvm=/opt/llvm

If you choose to build LLVM and Clang yourself, *and* if you choose to
keep your LLVM and Clang build trees separate, you can tell the
`configure' script where to find your separate Clang tree:

  # Use separate LLVM and Clang build trees, /work/my-{llvm,clang}
  configure --with-llvm=/work/my-llvm \
    --with-clang=/work/my-clang

You do *not* need to specify `--with-clang' if you build Clang within
your LLVM tree.  Also note that you must actually *build* LLVM and
Clang before building C-Reduce.

Note that assertions are enabled by default (which is probably what
you want).  To disable assertions:

  configure --disable-trans-assert

The generated Makefiles require GNU Make.  BSD Make will not work.
If you see weird make-time errors, please check that you are using
GNU Make.

* The CMake Way

From either the source directory or a build directory:

  cmake [source-dir] [options]
  make
  make install

If LLVM/Clang is not in your search path, you can tell CMake where to
find LLVM/Clang:

  # Use the LLVM/Clang tree rooted at /opt/llvm
  cmake [source-dir] -DCMAKE_PREFIX_PATH=/opt/llvm

Alternatively, if you choose to build LLVM and Clang yourself, you can
set the LLVM_DIR and/or Clang_DIR variables to paths where CMake can
find the `LLVMConfig.cmake' and/or `ClangConfig.cmake' files.  The
value of LLVM_DIR is usually "./lib/cmake/llvm", relative to your LLVM
build or install directory.  Similarly, the value of Clang_DIR is
usually "./lib/cmake/clang", relative to your Clang build or install
directory.  For example:

  # Use separate LLVM and Clang build trees, /work/my-{llvm,clang}
  cmake [source-dir] -DLLVM_DIR=/work/my-llvm/lib/cmake/llvm \
    -DClang_DIR=/work/my-clang/lib/cmake/clang

You do *not* need to set Clang_DIR if you build Clang within your LLVM
tree.  Also, note that you must actually *build* LLVM and Clang before
building C-Reduce.

Note that assertions are enabled by default (which is probably what
you want).  To disable assertions:

  cmake ... -DENABLE_TRANS_ASSERT=OFF

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Regarding LLVM versions:

Released versions of C-Reduce, and also our master branch at GitHub,
need to be compiled against specific released versions of LLVM, as
noted in this file.

Our GitHub repo usually also has a branch called llvm-svn-compatible
that supports building C-Reduce against LLVMs that are newer than the
last released version.  The most recent version of LLVM that the
llvm-svn-compatible branch is known to compile against is recorded in
LAST_KNOWN_WORKING_LLVM.  C-Reduce may happen to also build against
revisions before or after this, but we make no guarantees.

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