tools/llvm-config/llvm-config.in.in - llvm - Git at Google

 #!@PERL@
 ##===- tools/llvm-config ---------------------------------------*- perl -*-===##
 #
 #                     The LLVM Compiler Infrastructure
 #
 # This file was developed by Eric Kidd and is distributed under
 # the University of Illinois Open Source License. See LICENSE.TXT for details.
 #
 ##===----------------------------------------------------------------------===##
 #
 # Synopsis: Prints out compiler options needed to build against an installed
 #           copy of LLVM.
 #
 # Syntax:   llvm-config OPTIONS... [COMPONENTS...]
 #
 ##===----------------------------------------------------------------------===##

 use 5.006;
 use strict;
 use warnings;

 #---- begin autoconf values ----
 my $PACKAGE_NAME        = q{@PACKAGE_NAME@};
 my $VERSION             = q{@PACKAGE_VERSION@};
 my $PREFIX              = q{@LLVM_PREFIX@};
 my $LLVM_CONFIGTIME     = q{@LLVM_CONFIGTIME@};
 my $LLVM_SRC_ROOT       = q{@abs_top_srcdir@};
 my $LLVM_OBJ_ROOT       = q{@abs_top_builddir@};
 my $LLVM_ON_WIN32       = q{@LLVM_ON_WIN32@};
 my $LLVM_ON_UNIX        = q{@LLVM_ON_UNIX@};
 my $LLVMGCCDIR          = q{@LLVMGCCDIR@};
 my $LLVMGCC             = q{@LLVMGCC@};
 my $LLVMGXX             = q{@LLVMGXX@};
 my $LLVMGCC_VERSION     = q{@LLVMGCC_VERSION@};
 my $LLVMGCC_MAJVERS     = q{@LLVMGCC_MAJVERS@};
 my $ENDIAN              = q{@ENDIAN@};
 my $SHLIBEXT            = q{@SHLIBEXT@};
 my $EXEEXT              = q{@EXEEXT@};
 my $OS                  = q{@OS@};
 my $ARCH                = lc(q{@ARCH@});
 my $TARGET_TRIPLE       = q{@target@};
 my $TARGETS_TO_BUILD    = q{@TARGETS_TO_BUILD@};
 my $TARGET_HAS_JIT      = q{@TARGET_HAS_JIT@};
 my @TARGETS_BUILT       = map { lc($_) } qw{@TARGETS_TO_BUILD@};
 #---- end autoconf values ----

 # Must pretend x86_64 architecture is really x86, otherwise the native backend
 # won't get linked in.
 $ARCH = "x86" if $ARCH eq "x86_64";

 #---- begin Makefile values ----
 my $CFLAGS              = q{@LLVM_CFLAGS@};
 my $CXXFLAGS            = q{@LLVM_CXXFLAGS@};
 my $LDFLAGS             = q{@LLVM_LDFLAGS@};
 my $SYSTEM_LIBS         = q{@LIBS@};
 my $LLVM_BUILDMODE      = q{@LLVM_BUILDMODE@};
 #---- end Makefile values ----

 # Figure out where llvm-config is being run from.  Primarily, we care if it has
 # been installed, or is running from the build directory, which changes the
 # locations of some files.

 # Convert the current executable name into its directory (e.g. ".").
 my ($RUN_DIR) = ($0 =~ /^(.*)\/.*$/);

 # Turn the directory into an absolute directory on the file system, also pop up
 # from "bin" into the build or prefix dir.
 my $ABS_RUN_DIR = `cd $RUN_DIR/..; pwd`;
 chomp($ABS_RUN_DIR);

 # Compute the absolute object directory build, e.g. "foo/llvm/Debug".
 my $ABS_OBJ_ROOT = "$LLVM_OBJ_ROOT/$LLVM_BUILDMODE";
 $ABS_OBJ_ROOT = `cd $ABS_OBJ_ROOT; pwd` if (-d $ABS_OBJ_ROOT);
 chomp($ABS_OBJ_ROOT);

 my $INCLUDEDIR = "$ABS_RUN_DIR/include";
 my $LIBDIR     = "$ABS_RUN_DIR/lib";
 my $BINDIR     = "$ABS_RUN_DIR/bin";
 if ($ABS_RUN_DIR eq $ABS_OBJ_ROOT) {
   # If we are running out of the build directory, the include dir is in the
   # srcdir.
   $INCLUDEDIR = "$LLVM_SRC_ROOT/include";
 } else {
   # If installed, ignore the prefix the tree was configured with, use the
   # current prefix.
   $PREFIX = $ABS_RUN_DIR;
 }

 sub usage;
 sub fix_library_names (@);
 sub fix_library_files (@);
 sub expand_dependencies (@);
 sub name_map_entries;

 # Parse our command-line arguments.
 usage if @ARGV == 0;
 my @components;
 my $has_opt = 0;
 my $want_libs = 0;
 my $want_libnames = 0;
 my $want_libfiles = 0;
 my $want_components = 0;
 foreach my $arg (@ARGV) {
     if ($arg =~ /^-/) {
         if ($arg eq "--version") {
             $has_opt = 1; print "$VERSION\n";
         } elsif ($arg eq "--prefix") {
             $has_opt = 1; print "$PREFIX\n";
         } elsif ($arg eq "--bindir") {
             $has_opt = 1; print "$BINDIR\n";
         } elsif ($arg eq "--includedir") {
             $has_opt = 1; print "$INCLUDEDIR\n";
         } elsif ($arg eq "--libdir") {
             $has_opt = 1; print "$LIBDIR\n";
         } elsif ($arg eq "--cflags") {
             $has_opt = 1; print "-I$INCLUDEDIR $CFLAGS\n";
         } elsif ($arg eq "--cxxflags") {
             $has_opt = 1; print "-I$INCLUDEDIR $CXXFLAGS\n";
         } elsif ($arg eq "--ldflags") {
             $has_opt = 1; print "-L$LIBDIR $LDFLAGS $SYSTEM_LIBS\n";
         } elsif ($arg eq "--libs") {
             $has_opt = 1; $want_libs = 1;
         } elsif ($arg eq "--libnames") {
             $has_opt = 1; $want_libnames = 1;
         } elsif ($arg eq "--libfiles") {
             $has_opt = 1; $want_libfiles = 1;
         } elsif ($arg eq "--components") {
             $has_opt = 1; print join(' ', name_map_entries), "\n";
         } elsif ($arg eq "--targets-built") {
             $has_opt = 1; print join(' ', @TARGETS_BUILT), "\n";
         } elsif ($arg eq "--host-target") {
             $has_opt = 1; print "$TARGET_TRIPLE\n";
         } elsif ($arg eq "--build-mode") {
             $has_opt = 1; print "$LLVM_BUILDMODE\n";
         } elsif ($arg eq "--obj-root") {
             $has_opt = 1; print `cd $LLVM_OBJ_ROOT/; pwd`;
         } elsif ($arg eq "--src-root") {
             $has_opt = 1; print `cd $LLVM_SRC_ROOT/; pwd`;
         } else {
             usage();
         }
     } else {
         push @components, $arg;
     }
 }

 # If no options were specified, fail.
 usage unless $has_opt;

 # If no components were specified, default to 'all'.
 if (@components == 0) {
     push @components, 'all';
 }

 # Force component names to lower case.
 @components = map lc, @components;

 # Handle any arguments which require building our dependency graph.
 if ($want_libs || $want_libnames || $want_libfiles) {
     my @libs = expand_dependencies(@components);
     print join(' ', fix_library_names(@libs)), "\n" if ($want_libs);
     print join(' ',  @libs), "\n" if ($want_libnames);
     print join(' ', fix_library_files(@libs)), "\n" if ($want_libfiles);
 }

 exit 0;

 #==========================================================================
 #  Support Routines
 #==========================================================================

 sub usage {
     print STDERR <<__EOD__;
 Usage: llvm-config <OPTION>... [<COMPONENT>...]

 Get various configuration information needed to compile programs which use
 LLVM.  Typically called from 'configure' scripts.  Examples:
   llvm-config --cxxflags
   llvm-config --ldflags
   llvm-config --libs engine bcreader scalaropts

 Options:
   --version              Print LLVM version.
   --prefix               Print the installation prefix.
   --src-root             Print the source root LLVM was built from.
   --obj-root             Print the object root used to build LLVM.
   --bindir               Directory containing LLVM executables.
   --includedir           Directory containing LLVM headers.
   --libdir               Directory containing LLVM libraries.
   --cflags               C compiler flags for files that include LLVM headers.
   --cxxflags             C++ compiler flags for files that include LLVM headers.
   --ldflags              Print Linker flags.
   --libs                 Libraries needed to link against LLVM components.
   --libnames             Bare library names for in-tree builds.
   --libfiles             Fully qualified library filenames for makefile depends.
   --components           List of all possible components.
   --targets-built        List of all targets currently built.
   --host-target          Target triple used to configure LLVM.
   --build-mode           Print build mode of LLVM tree (e.g. Debug or Release).
 Typical components:
   all                    All LLVM libraries (default).
   backend                Either a native backend or the C backend.
   engine                 Either a native JIT or a bytecode interpreter.
 __EOD__
     exit(1);
 }

 # Use -lfoo instead of libfoo.a whenever possible, and add directories to
 # files which can't be found using -L.
 sub fix_library_names (@) {
     my @libs = @_;
     my @result;
     foreach my $lib (@libs) {
         # Transform the bare library name appropriately.
         my ($basename) = ($lib =~ /^lib([^.]*)\.a/);
         if (defined $basename) {
             push @result, "-l$basename";
         } else {
             push @result, "$LIBDIR/$lib";
         }
     }
     return @result;
 }

 # Turn the list of libraries into a list of files.
 sub fix_library_files(@) {
     my @libs = @_;
     my @result;
     foreach my $lib (@libs) {
         # Transform the bare library name into a filename.
         push @result, "$LIBDIR/$lib";
     }
     return @result;
 }

 #==========================================================================
 #  Library Dependency Analysis
 #==========================================================================
 #  Given a few human-readable library names, find all their dependencies
 #  and sort them into an order which the linker will like.  If we packed
 #  our libraries into fewer archives, we could make the linker do much
 #  of this work for us.
 #
 #  Libraries have two different types of names in this code: Human-friendly
 #  "component" names entered on the command-line, and the raw file names
 #  we use internally (and ultimately pass to the linker).
 #
 #  To understand this code, you'll need a working knowledge of Perl 5,
 #  and possibly some quality time with 'man perlref'.

 sub load_dependencies;
 sub build_name_map;
 sub have_native_backend;
 sub find_best_engine;
 sub expand_names (@);
 sub find_all_required_sets (@);
 sub find_all_required_sets_helper ($$@);

 # Each "set" contains one or more libraries which must be included as a
 # group (due to cyclic dependencies).  Sets are represented as a Perl array
 # reference pointing to a list of internal library names.
 my @SETS;

 # Various mapping tables.
 my %LIB_TO_SET_MAP; # Maps internal library names to their sets.
 my %SET_DEPS;       # Maps sets to a list of libraries they depend on.
 my %NAME_MAP;       # Maps human-entered names to internal names.

 # Have our dependencies been loaded yet?
 my $DEPENDENCIES_LOADED = 0;

 # Given a list of human-friendly component names, translate them into a
 # complete set of linker arguments.
 sub expand_dependencies (@) {
     my @libs = @_;
     load_dependencies;
     my @required_sets = find_all_required_sets(expand_names(@libs));
     my @sorted_sets = topologically_sort_sets(@required_sets);

     # Expand the library sets into libraries.
     my @result;
     foreach my $set (@sorted_sets) { push @result, @{$set}; }
     return @result;
 }

 # Load in the raw dependency data stored at the end of this file.
 sub load_dependencies {
     return if $DEPENDENCIES_LOADED;
     $DEPENDENCIES_LOADED = 1;
     while (<DATA>) {
         # Parse our line.
         my ($libs, $deps) = /^\s*([^:]+):\s*(.*)\s*$/;
         die "Malformed dependency data" unless defined $deps;
         my @libs = split(' ', $libs);
         my @deps = split(' ', $deps);

         # Record our dependency data.
         my $set = \@libs;
         push @SETS, $set;
         foreach my $lib (@libs) { $LIB_TO_SET_MAP{$lib} = $set; }
         $SET_DEPS{$set} = \@deps;
     }
     build_name_map;
 }

 # Build a map converting human-friendly component names into internal
 # library names.
 sub build_name_map {
     # Add entries for all the actual libraries.
     foreach my $set (@SETS) {
         foreach my $lib (sort @$set) {
             my $short_name = $lib;
             $short_name =~ s/^(lib)?LLVM([^.]*)\..*$/$2/;
             $short_name =~ tr/A-Z/a-z/;
             $NAME_MAP{$short_name} = [$lib];
         }
     }

     # Add virtual entries.
     $NAME_MAP{'native'}  = have_native_backend() ? [$ARCH] : [];
     $NAME_MAP{'backend'} = have_native_backend() ? ['native'] : ['cbackend'];
     $NAME_MAP{'engine'}  = find_best_engine;
     $NAME_MAP{'all'}     = [name_map_entries];   # Must be last.
 }

 # Return true if we have a native backend to use.
 sub have_native_backend {
     my %BUILT;
     foreach my $target (@TARGETS_BUILT) { $BUILT{$target} = 1; }
     return defined $NAME_MAP{$ARCH} && defined $BUILT{$ARCH};
 }

 # Find a working subclass of ExecutionEngine for this platform.
 sub find_best_engine {
     if (have_native_backend && $TARGET_HAS_JIT) {
         return ['jit', 'native'];
     } else {
         return ['interpreter'];
     }
 }

 # Get all the human-friendly component names.
 sub name_map_entries {
     load_dependencies;
     return sort keys %NAME_MAP;
 }

 # Map human-readable names to internal library names.
 sub expand_names (@) {
     my @names = @_;
     my @result;
     foreach my $name (@names) {
         if (defined $LIB_TO_SET_MAP{$name}) {
             # We've hit bottom: An actual library name.
             push @result, $name;
         } elsif (defined $NAME_MAP{$name}) {
             # We've found a short name to expand.
             push @result, expand_names(@{$NAME_MAP{$name}});
         } else {
             print STDERR "llvm-config: unknown component name: $name\n";
             exit(1);
         }
     }
     return @result;
 }

 # Given a list of internal library names, return all sets of libraries which
 # will need to be included by the linker (in no particular order).
 sub find_all_required_sets (@) {
     my @libs = @_;
     my %sets_added;
     my @result;
     find_all_required_sets_helper(\%sets_added, \@result, @libs);
     return @result;
 }

 # Recursive closures are pretty broken in Perl, so we're going to separate
 # this function from find_all_required_sets and pass in the state we need
 # manually, as references.  Yes, this is fairly unpleasant.
 sub find_all_required_sets_helper ($$@) {
     my ($sets_added, $result, @libs) = @_;
     foreach my $lib (@libs) {
         my $set = $LIB_TO_SET_MAP{$lib};
         next if defined $$sets_added{$set};
         $$sets_added{$set} = 1;
         push @$result, $set;
         find_all_required_sets_helper($sets_added, $result, @{$SET_DEPS{$set}});
     }
 }

 # Print a list of sets, with a label.  Used for debugging.
 sub print_sets ($@) {
     my ($label, @sets) = @_;
     my @output;
     foreach my $set (@sets) { push @output, join(',', @$set); }
     print "$label: ", join(';', @output), "\n";
 }

 # Returns true if $lib is a key in $added.
 sub has_lib_been_added ($$) {
     my ($added, $lib) = @_;
     return defined $$added{$LIB_TO_SET_MAP{$lib}};
 }

 # Returns true if all the dependencies of $set appear in $added.
 sub have_all_deps_been_added ($$) {
     my ($added, $set) = @_;
     #print_sets("  Checking", $set);
     #print_sets("     Wants", $SET_DEPS{$set});
     foreach my $lib (@{$SET_DEPS{$set}}) {
         return 0 unless has_lib_been_added($added, $lib);
     }
     return 1;
 }

 # Given a list of sets, topologically sort them using dependencies.
 sub topologically_sort_sets (@) {
     my @sets = @_;
     my %added;
     my @result;
     SCAN: while (@sets) { # We'll delete items from @sets as we go.
         #print_sets("So far", reverse(@result));
         #print_sets("Remaining", @sets);
         for (my $i = 0; $i < @sets; ++$i) {
             my $set = $sets[$i];
             if (have_all_deps_been_added(\%added, $set)) {
                 push @result, $set;
                 $added{$set} = 1;
                 #print "Removing $i.\n";
                 splice(@sets, $i, 1);
                 next SCAN; # Restart our scan.
             }
         }
         die "Can't find a library with no dependencies";
     }
     return reverse(@result);
 }

 # Our library dependency data will be added after the '__END__' token, and will
 # be read through the magic <DATA> filehandle.
 __END__
	#!@PERL@
	##===- tools/llvm-config ---------------------------------------- perl --===##
	#
	# The LLVM Compiler Infrastructure
	#
	# This file was developed by Eric Kidd and is distributed under
	# the University of Illinois Open Source License. See LICENSE.TXT for details.
	#
	##===----------------------------------------------------------------------===##
	#
	# Synopsis: Prints out compiler options needed to build against an installed
	# copy of LLVM.
	#
	# Syntax: llvm-config OPTIONS... [COMPONENTS...]
	#
	##===----------------------------------------------------------------------===##

	use 5.006;
	use strict;
	use warnings;

	#---- begin autoconf values ----
	my $PACKAGE_NAME = q{@PACKAGE_NAME@};
	my $VERSION = q{@PACKAGE_VERSION@};
	my $PREFIX = q{@LLVM_PREFIX@};
	my $LLVM_CONFIGTIME = q{@LLVM_CONFIGTIME@};
	my $LLVM_SRC_ROOT = q{@abs_top_srcdir@};
	my $LLVM_OBJ_ROOT = q{@abs_top_builddir@};
	my $LLVM_ON_WIN32 = q{@LLVM_ON_WIN32@};
	my $LLVM_ON_UNIX = q{@LLVM_ON_UNIX@};
	my $LLVMGCCDIR = q{@LLVMGCCDIR@};
	my $LLVMGCC = q{@LLVMGCC@};
	my $LLVMGXX = q{@LLVMGXX@};
	my $LLVMGCC_VERSION = q{@LLVMGCC_VERSION@};
	my $LLVMGCC_MAJVERS = q{@LLVMGCC_MAJVERS@};
	my $ENDIAN = q{@ENDIAN@};
	my $SHLIBEXT = q{@SHLIBEXT@};
	my $EXEEXT = q{@EXEEXT@};
	my $OS = q{@OS@};
	my $ARCH = lc(q{@ARCH@});
	my $TARGET_TRIPLE = q{@target@};
	my $TARGETS_TO_BUILD = q{@TARGETS_TO_BUILD@};
	my $TARGET_HAS_JIT = q{@TARGET_HAS_JIT@};
	my @TARGETS_BUILT = map { lc($_) } qw{@TARGETS_TO_BUILD@};
	#---- end autoconf values ----

	# Must pretend x86_64 architecture is really x86, otherwise the native backend
	# won't get linked in.
	$ARCH = "x86" if $ARCH eq "x86_64";

	#---- begin Makefile values ----
	my $CFLAGS = q{@LLVM_CFLAGS@};
	my $CXXFLAGS = q{@LLVM_CXXFLAGS@};
	my $LDFLAGS = q{@LLVM_LDFLAGS@};
	my $SYSTEM_LIBS = q{@LIBS@};
	my $LLVM_BUILDMODE = q{@LLVM_BUILDMODE@};
	#---- end Makefile values ----

	# Figure out where llvm-config is being run from. Primarily, we care if it has
	# been installed, or is running from the build directory, which changes the
	# locations of some files.

	# Convert the current executable name into its directory (e.g. ".").
	my ($RUN_DIR) = ($0 =~ /^(.)\/.$/);

	# Turn the directory into an absolute directory on the file system, also pop up
	# from "bin" into the build or prefix dir.
	my $ABS_RUN_DIR = `cd $RUN_DIR/..; pwd`;
	chomp($ABS_RUN_DIR);

	# Compute the absolute object directory build, e.g. "foo/llvm/Debug".
	my $ABS_OBJ_ROOT = "$LLVM_OBJ_ROOT/$LLVM_BUILDMODE";
	$ABS_OBJ_ROOT = `cd $ABS_OBJ_ROOT; pwd` if (-d $ABS_OBJ_ROOT);
	chomp($ABS_OBJ_ROOT);

	my $INCLUDEDIR = "$ABS_RUN_DIR/include";
	my $LIBDIR = "$ABS_RUN_DIR/lib";
	my $BINDIR = "$ABS_RUN_DIR/bin";
	if ($ABS_RUN_DIR eq $ABS_OBJ_ROOT) {
	# If we are running out of the build directory, the include dir is in the
	# srcdir.
	$INCLUDEDIR = "$LLVM_SRC_ROOT/include";
	} else {
	# If installed, ignore the prefix the tree was configured with, use the
	# current prefix.
	$PREFIX = $ABS_RUN_DIR;
	}

	sub usage;
	sub fix_library_names (@);
	sub fix_library_files (@);
	sub expand_dependencies (@);
	sub name_map_entries;

	# Parse our command-line arguments.
	usage if @ARGV == 0;
	my @components;
	my $has_opt = 0;
	my $want_libs = 0;
	my $want_libnames = 0;
	my $want_libfiles = 0;
	my $want_components = 0;
	foreach my $arg (@ARGV) {
	if ($arg =~ /^-/) {
	if ($arg eq "--version") {
	$has_opt = 1; print "$VERSION\n";
	} elsif ($arg eq "--prefix") {
	$has_opt = 1; print "$PREFIX\n";
	} elsif ($arg eq "--bindir") {
	$has_opt = 1; print "$BINDIR\n";
	} elsif ($arg eq "--includedir") {
	$has_opt = 1; print "$INCLUDEDIR\n";
	} elsif ($arg eq "--libdir") {
	$has_opt = 1; print "$LIBDIR\n";
	} elsif ($arg eq "--cflags") {
	$has_opt = 1; print "-I$INCLUDEDIR $CFLAGS\n";
	} elsif ($arg eq "--cxxflags") {
	$has_opt = 1; print "-I$INCLUDEDIR $CXXFLAGS\n";
	} elsif ($arg eq "--ldflags") {
	$has_opt = 1; print "-L$LIBDIR $LDFLAGS $SYSTEM_LIBS\n";
	} elsif ($arg eq "--libs") {
	$has_opt = 1; $want_libs = 1;
	} elsif ($arg eq "--libnames") {
	$has_opt = 1; $want_libnames = 1;
	} elsif ($arg eq "--libfiles") {
	$has_opt = 1; $want_libfiles = 1;
	} elsif ($arg eq "--components") {
	$has_opt = 1; print join(' ', name_map_entries), "\n";
	} elsif ($arg eq "--targets-built") {
	$has_opt = 1; print join(' ', @TARGETS_BUILT), "\n";
	} elsif ($arg eq "--host-target") {
	$has_opt = 1; print "$TARGET_TRIPLE\n";
	} elsif ($arg eq "--build-mode") {
	$has_opt = 1; print "$LLVM_BUILDMODE\n";
	} elsif ($arg eq "--obj-root") {
	$has_opt = 1; print `cd $LLVM_OBJ_ROOT/; pwd`;
	} elsif ($arg eq "--src-root") {
	$has_opt = 1; print `cd $LLVM_SRC_ROOT/; pwd`;
	} else {
	usage();
	}
	} else {
	push @components, $arg;
	}
	}

	# If no options were specified, fail.
	usage unless $has_opt;

	# If no components were specified, default to 'all'.
	if (@components == 0) {
	push @components, 'all';
	}

	# Force component names to lower case.
	@components = map lc, @components;

	# Handle any arguments which require building our dependency graph.
	if ($want_libs \|\| $want_libnames \|\| $want_libfiles) {
	my @libs = expand_dependencies(@components);
	print join(' ', fix_library_names(@libs)), "\n" if ($want_libs);
	print join(' ', @libs), "\n" if ($want_libnames);
	print join(' ', fix_library_files(@libs)), "\n" if ($want_libfiles);
	}

	exit 0;

	#==========================================================================
	# Support Routines
	#==========================================================================

	sub usage {
	print STDERR <<__EOD__;
	Usage: llvm-config <OPTION>... [<COMPONENT>...]

	Get various configuration information needed to compile programs which use
	LLVM. Typically called from 'configure' scripts. Examples:
	llvm-config --cxxflags
	llvm-config --ldflags
	llvm-config --libs engine bcreader scalaropts

	Options:
	--version Print LLVM version.
	--prefix Print the installation prefix.
	--src-root Print the source root LLVM was built from.
	--obj-root Print the object root used to build LLVM.
	--bindir Directory containing LLVM executables.
	--includedir Directory containing LLVM headers.
	--libdir Directory containing LLVM libraries.
	--cflags C compiler flags for files that include LLVM headers.
	--cxxflags C++ compiler flags for files that include LLVM headers.
	--ldflags Print Linker flags.
	--libs Libraries needed to link against LLVM components.
	--libnames Bare library names for in-tree builds.
	--libfiles Fully qualified library filenames for makefile depends.
	--components List of all possible components.
	--targets-built List of all targets currently built.
	--host-target Target triple used to configure LLVM.
	--build-mode Print build mode of LLVM tree (e.g. Debug or Release).
	Typical components:
	all All LLVM libraries (default).
	backend Either a native backend or the C backend.
	engine Either a native JIT or a bytecode interpreter.
	__EOD__
	exit(1);
	}

	# Use -lfoo instead of libfoo.a whenever possible, and add directories to
	# files which can't be found using -L.
	sub fix_library_names (@) {
	my @libs = @_;
	my @result;
	foreach my $lib (@libs) {
	# Transform the bare library name appropriately.
	my ($basename) = ($lib =~ /^lib([^.]*)\.a/);
	if (defined $basename) {
	push @result, "-l$basename";
	} else {
	push @result, "$LIBDIR/$lib";
	}
	}
	return @result;
	}

	# Turn the list of libraries into a list of files.
	sub fix_library_files(@) {
	my @libs = @_;
	my @result;
	foreach my $lib (@libs) {
	# Transform the bare library name into a filename.
	push @result, "$LIBDIR/$lib";
	}
	return @result;
	}

	#==========================================================================
	# Library Dependency Analysis
	#==========================================================================
	# Given a few human-readable library names, find all their dependencies
	# and sort them into an order which the linker will like. If we packed
	# our libraries into fewer archives, we could make the linker do much
	# of this work for us.
	#
	# Libraries have two different types of names in this code: Human-friendly
	# "component" names entered on the command-line, and the raw file names
	# we use internally (and ultimately pass to the linker).
	#
	# To understand this code, you'll need a working knowledge of Perl 5,
	# and possibly some quality time with 'man perlref'.

	sub load_dependencies;
	sub build_name_map;
	sub have_native_backend;
	sub find_best_engine;
	sub expand_names (@);
	sub find_all_required_sets (@);
	sub find_all_required_sets_helper ($$@);

	# Each "set" contains one or more libraries which must be included as a
	# group (due to cyclic dependencies). Sets are represented as a Perl array
	# reference pointing to a list of internal library names.
	my @SETS;

	# Various mapping tables.
	my %LIB_TO_SET_MAP; # Maps internal library names to their sets.
	my %SET_DEPS; # Maps sets to a list of libraries they depend on.
	my %NAME_MAP; # Maps human-entered names to internal names.

	# Have our dependencies been loaded yet?
	my $DEPENDENCIES_LOADED = 0;

	# Given a list of human-friendly component names, translate them into a
	# complete set of linker arguments.
	sub expand_dependencies (@) {
	my @libs = @_;
	load_dependencies;
	my @required_sets = find_all_required_sets(expand_names(@libs));
	my @sorted_sets = topologically_sort_sets(@required_sets);

	# Expand the library sets into libraries.
	my @result;
	foreach my $set (@sorted_sets) { push @result, @{$set}; }
	return @result;
	}

	# Load in the raw dependency data stored at the end of this file.
	sub load_dependencies {
	return if $DEPENDENCIES_LOADED;
	$DEPENDENCIES_LOADED = 1;
	while (<DATA>) {
	# Parse our line.
	my ($libs, $deps) = /^\s([^:]+):\s(.)\s$/;
	die "Malformed dependency data" unless defined $deps;
	my @libs = split(' ', $libs);
	my @deps = split(' ', $deps);

	# Record our dependency data.
	my $set = \@libs;
	push @SETS, $set;
	foreach my $lib (@libs) { $LIB_TO_SET_MAP{$lib} = $set; }
	$SET_DEPS{$set} = \@deps;
	}
	build_name_map;
	}

	# Build a map converting human-friendly component names into internal
	# library names.
	sub build_name_map {
	# Add entries for all the actual libraries.
	foreach my $set (@SETS) {
	foreach my $lib (sort @$set) {
	my $short_name = $lib;
	$short_name =~ s/^(lib)?LLVM([^.])\..$/$2/;
	$short_name =~ tr/A-Z/a-z/;
	$NAME_MAP{$short_name} = [$lib];
	}
	}

	# Add virtual entries.
	$NAME_MAP{'native'} = have_native_backend() ? [$ARCH] : [];
	$NAME_MAP{'backend'} = have_native_backend() ? ['native'] : ['cbackend'];
	$NAME_MAP{'engine'} = find_best_engine;
	$NAME_MAP{'all'} = [name_map_entries]; # Must be last.
	}

	# Return true if we have a native backend to use.
	sub have_native_backend {
	my %BUILT;
	foreach my $target (@TARGETS_BUILT) { $BUILT{$target} = 1; }
	return defined $NAME_MAP{$ARCH} && defined $BUILT{$ARCH};
	}

	# Find a working subclass of ExecutionEngine for this platform.
	sub find_best_engine {
	if (have_native_backend && $TARGET_HAS_JIT) {
	return ['jit', 'native'];
	} else {
	return ['interpreter'];
	}
	}

	# Get all the human-friendly component names.
	sub name_map_entries {
	load_dependencies;
	return sort keys %NAME_MAP;
	}

	# Map human-readable names to internal library names.
	sub expand_names (@) {
	my @names = @_;
	my @result;
	foreach my $name (@names) {
	if (defined $LIB_TO_SET_MAP{$name}) {
	# We've hit bottom: An actual library name.
	push @result, $name;
	} elsif (defined $NAME_MAP{$name}) {
	# We've found a short name to expand.
	push @result, expand_names(@{$NAME_MAP{$name}});
	} else {
	print STDERR "llvm-config: unknown component name: $name\n";
	exit(1);
	}
	}
	return @result;
	}

	# Given a list of internal library names, return all sets of libraries which
	# will need to be included by the linker (in no particular order).
	sub find_all_required_sets (@) {
	my @libs = @_;
	my %sets_added;
	my @result;
	find_all_required_sets_helper(\%sets_added, \@result, @libs);
	return @result;
	}

	# Recursive closures are pretty broken in Perl, so we're going to separate
	# this function from find_all_required_sets and pass in the state we need
	# manually, as references. Yes, this is fairly unpleasant.
	sub find_all_required_sets_helper ($$@) {
	my ($sets_added, $result, @libs) = @_;
	foreach my $lib (@libs) {
	my $set = $LIB_TO_SET_MAP{$lib};
	next if defined $$sets_added{$set};
	$$sets_added{$set} = 1;
	push @$result, $set;
	find_all_required_sets_helper($sets_added, $result, @{$SET_DEPS{$set}});
	}
	}

	# Print a list of sets, with a label. Used for debugging.
	sub print_sets ($@) {
	my ($label, @sets) = @_;
	my @output;
	foreach my $set (@sets) { push @output, join(',', @$set); }
	print "$label: ", join(';', @output), "\n";
	}

	# Returns true if $lib is a key in $added.
	sub has_lib_been_added ($$) {
	my ($added, $lib) = @_;
	return defined $$added{$LIB_TO_SET_MAP{$lib}};
	}

	# Returns true if all the dependencies of $set appear in $added.
	sub have_all_deps_been_added ($$) {
	my ($added, $set) = @_;
	#print_sets(" Checking", $set);
	#print_sets(" Wants", $SET_DEPS{$set});
	foreach my $lib (@{$SET_DEPS{$set}}) {
	return 0 unless has_lib_been_added($added, $lib);
	}
	return 1;
	}

	# Given a list of sets, topologically sort them using dependencies.
	sub topologically_sort_sets (@) {
	my @sets = @_;
	my %added;
	my @result;
	SCAN: while (@sets) { # We'll delete items from @sets as we go.
	#print_sets("So far", reverse(@result));
	#print_sets("Remaining", @sets);
	for (my $i = 0; $i < @sets; ++$i) {
	my $set = $sets[$i];
	if (have_all_deps_been_added(\%added, $set)) {
	push @result, $set;
	$added{$set} = 1;
	#print "Removing $i.\n";
	splice(@sets, $i, 1);
	next SCAN; # Restart our scan.
	}
	}
	die "Can't find a library with no dependencies";
	}
	return reverse(@result);
	}

	# Our library dependency data will be added after the '__END__' token, and will
	# be read through the magic <DATA> filehandle.
	__END__