Fix build with CMake if LLVM_USE_INTEL_JITEVENTS option is enabled
[oota-llvm.git] / utils / llvm-build / llvmbuild / main.py
index 892242dc30ef2fd766765490faed529bb40d999d..36c7d53add1321df4c5775c871bb4bb6932324ef 100644 (file)
@@ -1,36 +1,89 @@
+from __future__ import absolute_import
 import os
 import sys
 
-import componentinfo
+import llvmbuild.componentinfo as componentinfo
+import llvmbuild.configutil as configutil
 
-from util import *
+from llvmbuild.util import fatal, note
+
+###
+
+def cmake_quote_string(value):
+    """
+    cmake_quote_string(value) -> str
+
+    Return a quoted form of the given value that is suitable for use in CMake
+    language files.
+    """
+
+    # Currently, we only handle escaping backslashes.
+    value = value.replace("\\", "\\\\")
+
+    return value
+
+def cmake_quote_path(value):
+    """
+    cmake_quote_path(value) -> str
+
+    Return a quoted form of the given value that is suitable for use in CMake
+    language files.
+    """
+
+    # CMake has a bug in it's Makefile generator that doesn't properly quote
+    # strings it generates. So instead of using proper quoting, we just use "/"
+    # style paths.  Currently, we only handle escaping backslashes.
+    value = value.replace("\\", "/")
+
+    return value
+
+def mk_quote_string_for_target(value):
+    """
+    mk_quote_string_for_target(target_name) -> str
+
+    Return a quoted form of the given target_name suitable for including in a
+    Makefile as a target name.
+    """
+
+    # The only quoting we currently perform is for ':', to support msys users.
+    return value.replace(":", "\\:")
+
+def make_install_dir(path):
+    """
+    make_install_dir(path) -> None
+
+    Create the given directory path for installation, including any parents.
+    """
+
+    # os.makedirs considers it an error to be called with an existent path.
+    if not os.path.exists(path):
+        os.makedirs(path)
 
 ###
 
 class LLVMProjectInfo(object):
     @staticmethod
     def load_infos_from_path(llvmbuild_source_root):
-        # FIXME: Implement a simple subpath file list cache, so we don't restat
-        # directories we have already traversed.
-
-        # First, discover all the LLVMBuild.txt files.
-        for dirpath,dirnames,filenames in os.walk(llvmbuild_source_root,
-                                                  followlinks = True):
-            # If there is no LLVMBuild.txt file in a directory, we don't recurse
-            # past it. This is a simple way to prune our search, although it
-            # makes it easy for users to add LLVMBuild.txt files in places they
-            # won't be seen.
-            if 'LLVMBuild.txt' not in filenames:
-                del dirnames[:]
-                continue
-
-            # Otherwise, load the LLVMBuild file in this directory.
-            assert dirpath.startswith(llvmbuild_source_root)
-            subpath = '/' + dirpath[len(llvmbuild_source_root)+1:]
-            llvmbuild_path = os.path.join(dirpath, 'LLVMBuild.txt')
-            for info in componentinfo.load_from_path(llvmbuild_path, subpath):
+        def recurse(subpath):
+            # Load the LLVMBuild file.
+            llvmbuild_path = os.path.join(llvmbuild_source_root + subpath,
+                                          'LLVMBuild.txt')
+            if not os.path.exists(llvmbuild_path):
+                fatal("missing LLVMBuild.txt file at: %r" % (llvmbuild_path,))
+
+            # Parse the components from it.
+            common,info_iter = componentinfo.load_from_path(llvmbuild_path,
+                                                            subpath)
+            for info in info_iter:
                 yield info
 
+            # Recurse into the specified subdirectories.
+            for subdir in common.get_list("subdirectories"):
+                for item in recurse(os.path.join(subpath, subdir)):
+                    yield item
+
+        return recurse("/")
+
     @staticmethod
     def load_from_path(source_root, llvmbuild_source_root):
         infos = list(
@@ -41,12 +94,26 @@ class LLVMProjectInfo(object):
     def __init__(self, source_root, component_infos):
         # Store our simple ivars.
         self.source_root = source_root
-        self.component_infos = component_infos
+        self.component_infos = list(component_infos)
+        self.component_info_map = None
+        self.ordered_component_infos = None
+
+    def validate_components(self):
+        """validate_components() -> None
+
+        Validate that the project components are well-defined. Among other
+        things, this checks that:
+          - Components have valid references.
+          - Components references do not form cycles.
+
+        We also construct the map from component names to info, and the
+        topological ordering of components.
+        """
 
         # Create the component info map and validate that component names are
         # unique.
         self.component_info_map = {}
-        for ci in component_infos:
+        for ci in self.component_infos:
             existing = self.component_info_map.get(ci.name)
             if existing is not None:
                 # We found a duplicate component name, report it and error out.
@@ -115,9 +182,11 @@ class LLVMProjectInfo(object):
         # out easily. If we don't, we should special case the check.
 
         self.ordered_component_infos = []
-        components_to_visit = set(component_infos)
+        components_to_visit = sorted(
+            set(self.component_infos),
+            key = lambda c: c.name)
         while components_to_visit:
-            visit_component_info(iter(components_to_visit).next(), [], set())
+            visit_component_info(components_to_visit[0], [], set())
 
         # Canonicalize children lists.
         for c in self.ordered_component_infos:
@@ -125,7 +194,7 @@ class LLVMProjectInfo(object):
 
     def print_tree(self):
         def visit(node, depth = 0):
-            print '%s%-40s (%s)' % ('  '*depth, node.name, node.type_name)
+            print('%s%-40s (%s)' % ('  '*depth, node.name, node.type_name))
             for c in node.children:
                 visit(c, depth + 1)
         visit(self.component_info_map['$ROOT'])
@@ -141,14 +210,45 @@ class LLVMProjectInfo(object):
 
             info_basedir[ci.subpath] = info_basedir.get(ci.subpath, []) + [ci]
 
+        # Compute the list of subdirectories to scan.
+        subpath_subdirs = {}
+        for ci in self.component_infos:
+            # Ignore root components.
+            if ci.subpath == '/':
+                continue
+
+            # Otherwise, append this subpath to the parent list.
+            parent_path = os.path.dirname(ci.subpath)
+            subpath_subdirs[parent_path] = parent_list = subpath_subdirs.get(
+                parent_path, set())
+            parent_list.add(os.path.basename(ci.subpath))
+
         # Generate the build files.
         for subpath, infos in info_basedir.items():
             # Order the components by name to have a canonical ordering.
             infos.sort(key = lambda ci: ci.name)
 
             # Format the components into llvmbuild fragments.
-            fragments = filter(None, [ci.get_llvmbuild_fragment()
-                                      for ci in infos])
+            fragments = []
+
+            # Add the common fragments.
+            subdirectories = subpath_subdirs.get(subpath)
+            if subdirectories:
+                fragment = """\
+subdirectories = %s
+""" % (" ".join(sorted(subdirectories)),)
+                fragments.append(("common", fragment))
+
+            # Add the component fragments.
+            num_common_fragments = len(fragments)
+            for ci in infos:
+                fragment = ci.get_llvmbuild_fragment()
+                if fragment is None:
+                    continue
+
+                name = "component_%d" % (len(fragments) - num_common_fragments)
+                fragments.append((name, fragment))
+
             if not fragments:
                 continue
 
@@ -159,35 +259,95 @@ class LLVMProjectInfo(object):
             if not os.path.exists(directory_path):
                 os.makedirs(directory_path)
 
-            # Create the LLVMBuild file.
+            # In an effort to preserve comments (which aren't parsed), read in
+            # the original file and extract the comments. We only know how to
+            # associate comments that prefix a section name.
+            f = open(infos[0]._source_path)
+            comments_map = {}
+            comment_block = ""
+            for ln in f:
+                if ln.startswith(';'):
+                    comment_block += ln
+                elif ln.startswith('[') and ln.endswith(']\n'):
+                    comments_map[ln[1:-2]] = comment_block
+                else:
+                    comment_block = ""
+            f.close()
+
+            # Create the LLVMBuild fil[e.
             file_path = os.path.join(directory_path, 'LLVMBuild.txt')
             f = open(file_path, "w")
-            for i,fragment in enumerate(fragments):
-                print >>f, '[component_%d]' % i
+
+            # Write the header.
+            header_fmt = ';===- %s %s-*- Conf -*--===;'
+            header_name = '.' + os.path.join(subpath, 'LLVMBuild.txt')
+            header_pad = '-' * (80 - len(header_fmt % (header_name, '')))
+            header_string = header_fmt % (header_name, header_pad)
+            f.write("""\
+%s
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+""" % header_string)
+
+            # Write out each fragment.each component fragment.
+            for name,fragment in fragments:
+                comment = comments_map.get(name)
+                if comment is not None:
+                    f.write(comment)
+                f.write("[%s]\n" % name)
                 f.write(fragment)
-                print >>f
+                if fragment is not fragments[-1][1]:
+                    f.write('\n')
+
             f.close()
 
-    def write_library_table(self, output_path):
+    def write_library_table(self, output_path, enabled_optional_components):
         # Write out the mapping from component names to required libraries.
         #
         # We do this in topological order so that we know we can append the
         # dependencies for added library groups.
         entries = {}
         for c in self.ordered_component_infos:
-            # Only Library and LibraryGroup components are in the table.
-            if c.type_name not in ('Library', 'LibraryGroup'):
+            # Skip optional components which are not enabled.
+            if c.type_name == 'OptionalLibrary' \
+                and c.name not in enabled_optional_components:
+                continue
+
+            # Skip target groups which are not enabled.
+            tg = c.get_parent_target_group()
+            if tg and not tg.enabled:
+                continue
+
+            # Only certain components are in the table.
+            if c.type_name not in ('Library', 'OptionalLibrary', \
+                                   'LibraryGroup', 'TargetGroup'):
                 continue
 
             # Compute the llvm-config "component name". For historical reasons,
             # this is lowercased based on the library name.
             llvmconfig_component_name = c.get_llvmconfig_component_name()
-            
+
             # Get the library name, or None for LibraryGroups.
-            if c.type_name == 'LibraryGroup':
-                library_name = None
+            if c.type_name == 'Library' or c.type_name == 'OptionalLibrary':
+                library_name = c.get_prefixed_library_name()
+                is_installed = c.installed
             else:
-                library_name = c.get_library_name()
+                library_name = None
+                is_installed = True
 
             # Get the component names of all the required libraries.
             required_llvmconfig_component_names = [
@@ -200,28 +360,30 @@ class LLVMProjectInfo(object):
 
             # Add the entry.
             entries[c.name] = (llvmconfig_component_name, library_name,
-                               required_llvmconfig_component_names)
+                               required_llvmconfig_component_names,
+                               is_installed)
 
         # Convert to a list of entries and sort by name.
-        entries = entries.values()
+        entries = list(entries.values())
 
         # Create an 'all' pseudo component. We keep the dependency list small by
         # only listing entries that have no other dependents.
         root_entries = set(e[0] for e in entries)
-        for _,_,deps in entries:
+        for _,_,deps,_ in entries:
             root_entries -= set(deps)
-        entries.append(('all', None, root_entries))
+        entries.append(('all', None, root_entries, True))
 
         entries.sort()
 
         # Compute the maximum number of required libraries, plus one so there is
         # always a sentinel.
         max_required_libraries = max(len(deps)
-                                     for _,_,deps in entries) + 1
+                                     for _,_,deps,_ in entries) + 1
 
         # Write out the library table.
+        make_install_dir(os.path.dirname(output_path))
         f = open(output_path, 'w')
-        print >>f, """\
+        f.write("""\
 //===- llvm-build generated file --------------------------------*- C++ -*-===//
 //
 // Component Library Depenedency Table
@@ -229,60 +391,488 @@ class LLVMProjectInfo(object):
 // Automatically generated file, do not edit!
 //
 //===----------------------------------------------------------------------===//
-"""
-        print >>f, 'struct AvailableComponent {'
-        print >>f, '  /// The name of the component.'
-        print >>f, '  const char *Name;'
-        print >>f, ''
-        print >>f, '  /// The name of the library for this component (or NULL).'
-        print >>f, '  const char *Library;'
-        print >>f, ''
-        print >>f, '\
-  /// The list of libraries required when linking this component.'
-        print >>f, '  const char *RequiredLibraries[%d];' % (
-            max_required_libraries)
-        print >>f, '} AvailableComponents[%d] = {' % len(entries)
-        for name,library_name,required_names in entries:
+
+""")
+        f.write('struct AvailableComponent {\n')
+        f.write('  /// The name of the component.\n')
+        f.write('  const char *Name;\n')
+        f.write('\n')
+        f.write('  /// The name of the library for this component (or NULL).\n')
+        f.write('  const char *Library;\n')
+        f.write('\n')
+        f.write('  /// Whether the component is installed.\n')
+        f.write('  bool IsInstalled;\n')
+        f.write('\n')
+        f.write('\
+  /// The list of libraries required when linking this component.\n')
+        f.write('  const char *RequiredLibraries[%d];\n' % (
+            max_required_libraries))
+        f.write('} AvailableComponents[%d] = {\n' % len(entries))
+        for name,library_name,required_names,is_installed in entries:
             if library_name is None:
                 library_name_as_cstr = '0'
             else:
-                # If we had a project level component, we could derive the
-                # library prefix.
-                library_name_as_cstr = '"libLLVM%s.a"' % library_name
-            print >>f, '  { "%s", %s, { %s } },' % (
-                name, library_name_as_cstr,
+                library_name_as_cstr = '"lib%s.a"' % library_name
+            f.write('  { "%s", %s, %d, { %s } },\n' % (
+                name, library_name_as_cstr, is_installed,
                 ', '.join('"%s"' % dep
-                          for dep in required_names))
-        print >>f, '};'
+                          for dep in required_names)))
+        f.write('};\n')
+        f.close()
+
+    def get_required_libraries_for_component(self, ci, traverse_groups = False):
+        """
+        get_required_libraries_for_component(component_info) -> iter
+
+        Given a Library component info descriptor, return an iterator over all
+        of the directly required libraries for linking with this component. If
+        traverse_groups is True, then library and target groups will be
+        traversed to include their required libraries.
+        """
+
+        assert ci.type_name in ('Library', 'OptionalLibrary', 'LibraryGroup', 'TargetGroup')
+
+        for name in ci.required_libraries:
+            # Get the dependency info.
+            dep = self.component_info_map[name]
+
+            # If it is a library, yield it.
+            if dep.type_name == 'Library' or dep.type_name == 'OptionalLibrary':
+                yield dep
+                continue
+
+            # Otherwise if it is a group, yield or traverse depending on what
+            # was requested.
+            if dep.type_name in ('LibraryGroup', 'TargetGroup'):
+                if not traverse_groups:
+                    yield dep
+                    continue
+
+                for res in self.get_required_libraries_for_component(dep, True):
+                    yield res
+
+    def get_fragment_dependencies(self):
+        """
+        get_fragment_dependencies() -> iter
+
+        Compute the list of files (as absolute paths) on which the output
+        fragments depend (i.e., files for which a modification should trigger a
+        rebuild of the fragment).
+        """
+
+        # Construct a list of all the dependencies of the Makefile fragment
+        # itself. These include all the LLVMBuild files themselves, as well as
+        # all of our own sources.
+        #
+        # Many components may come from the same file, so we make sure to unique
+        # these.
+        build_paths = set()
+        for ci in self.component_infos:
+            p = os.path.join(self.source_root, ci.subpath[1:], 'LLVMBuild.txt')
+            if p not in build_paths:
+                yield p
+                build_paths.add(p)
+
+        # Gather the list of necessary sources by just finding all loaded
+        # modules that are inside the LLVM source tree.
+        for module in sys.modules.values():
+            # Find the module path.
+            if not hasattr(module, '__file__'):
+                continue
+            path = getattr(module, '__file__')
+            if not path:
+                continue
+
+            # Strip off any compiled suffix.
+            if os.path.splitext(path)[1] in ['.pyc', '.pyo', '.pyd']:
+                path = path[:-1]
+
+            # If the path exists and is in the source tree, consider it a
+            # dependency.
+            if (path.startswith(self.source_root) and os.path.exists(path)):
+                yield path
+
+    def write_cmake_fragment(self, output_path, enabled_optional_components):
+        """
+        write_cmake_fragment(output_path) -> None
+
+        Generate a CMake fragment which includes all of the collated LLVMBuild
+        information in a format that is easily digestible by a CMake. The exact
+        contents of this are closely tied to how the CMake configuration
+        integrates LLVMBuild, see CMakeLists.txt in the top-level.
+        """
+
+        dependencies = list(self.get_fragment_dependencies())
+
+        # Write out the CMake fragment.
+        make_install_dir(os.path.dirname(output_path))
+        f = open(output_path, 'w')
+
+        # Write the header.
+        header_fmt = '\
+#===-- %s - LLVMBuild Configuration for LLVM %s-*- CMake -*--===#'
+        header_name = os.path.basename(output_path)
+        header_pad = '-' * (80 - len(header_fmt % (header_name, '')))
+        header_string = header_fmt % (header_name, header_pad)
+        f.write("""\
+%s
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===------------------------------------------------------------------------===#
+#
+# This file contains the LLVMBuild project information in a format easily
+# consumed by the CMake based build system.
+#
+# This file is autogenerated by llvm-build, do not edit!
+#
+#===------------------------------------------------------------------------===#
+
+""" % header_string)
+
+        # Write the dependency information in the best way we can.
+        f.write("""
+# LLVMBuild CMake fragment dependencies.
+#
+# CMake has no builtin way to declare that the configuration depends on
+# a particular file. However, a side effect of configure_file is to add
+# said input file to CMake's internal dependency list. So, we use that
+# and a dummy output file to communicate the dependency information to
+# CMake.
+#
+# FIXME: File a CMake RFE to get a properly supported version of this
+# feature.
+""")
+        for dep in dependencies:
+            f.write("""\
+configure_file(\"%s\"
+               ${CMAKE_CURRENT_BINARY_DIR}/DummyConfigureOutput)\n""" % (
+                cmake_quote_path(dep),))
+
+        # Write the properties we use to encode the required library dependency
+        # information in a form CMake can easily use directly.
+        f.write("""
+# Explicit library dependency information.
+#
+# The following property assignments effectively create a map from component
+# names to required libraries, in a way that is easily accessed from CMake.
+""")
+        for ci in self.ordered_component_infos:
+            # Skip optional components which are not enabled.
+            if ci.type_name == 'OptionalLibrary' \
+                and ci.name not in enabled_optional_components:
+                continue
+
+            # We only write the information for certain components currently.
+            if ci.type_name not in ('Library', 'OptionalLibrary'):
+                continue
+
+            f.write("""\
+set_property(GLOBAL PROPERTY LLVMBUILD_LIB_DEPS_%s %s)\n""" % (
+                ci.get_prefixed_library_name(), " ".join(sorted(
+                     dep.get_prefixed_library_name()
+                     for dep in self.get_required_libraries_for_component(ci)))))
+
+        f.close()
+
+    def write_cmake_exports_fragment(self, output_path, enabled_optional_components):
+        """
+        write_cmake_exports_fragment(output_path) -> None
+
+        Generate a CMake fragment which includes LLVMBuild library
+        dependencies expressed similarly to how CMake would write
+        them via install(EXPORT).
+        """
+
+        dependencies = list(self.get_fragment_dependencies())
+
+        # Write out the CMake exports fragment.
+        make_install_dir(os.path.dirname(output_path))
+        f = open(output_path, 'w')
+
+        f.write("""\
+# Explicit library dependency information.
+#
+# The following property assignments tell CMake about link
+# dependencies of libraries imported from LLVM.
+""")
+        for ci in self.ordered_component_infos:
+            # Skip optional components which are not enabled.
+            if ci.type_name == 'OptionalLibrary' \
+                and ci.name not in enabled_optional_components:
+                continue
+
+            # We only write the information for libraries currently.
+            if ci.type_name not in ('Library', 'OptionalLibrary'):
+                continue
+
+            # Skip disabled targets.
+            tg = ci.get_parent_target_group()
+            if tg and not tg.enabled:
+                continue
+
+            f.write("""\
+set_property(TARGET %s PROPERTY IMPORTED_LINK_INTERFACE_LIBRARIES %s)\n""" % (
+                ci.get_prefixed_library_name(), " ".join(sorted(
+                     dep.get_prefixed_library_name()
+                     for dep in self.get_required_libraries_for_component(ci)))))
+
         f.close()
 
+    def write_make_fragment(self, output_path):
+        """
+        write_make_fragment(output_path) -> None
+
+        Generate a Makefile fragment which includes all of the collated
+        LLVMBuild information in a format that is easily digestible by a
+        Makefile. The exact contents of this are closely tied to how the LLVM
+        Makefiles integrate LLVMBuild, see Makefile.rules in the top-level.
+        """
+
+        dependencies = list(self.get_fragment_dependencies())
+
+        # Write out the Makefile fragment.
+        make_install_dir(os.path.dirname(output_path))
+        f = open(output_path, 'w')
+
+        # Write the header.
+        header_fmt = '\
+#===-- %s - LLVMBuild Configuration for LLVM %s-*- Makefile -*--===#'
+        header_name = os.path.basename(output_path)
+        header_pad = '-' * (80 - len(header_fmt % (header_name, '')))
+        header_string = header_fmt % (header_name, header_pad)
+        f.write("""\
+%s
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+#===------------------------------------------------------------------------===#
+#
+# This file contains the LLVMBuild project information in a format easily
+# consumed by the Makefile based build system.
+#
+# This file is autogenerated by llvm-build, do not edit!
+#
+#===------------------------------------------------------------------------===#
+
+""" % header_string)
+
+        # Write the dependencies for the fragment.
+        #
+        # FIXME: Technically, we need to properly quote for Make here.
+        f.write("""\
+# Clients must explicitly enable LLVMBUILD_INCLUDE_DEPENDENCIES to get
+# these dependencies. This is a compromise to help improve the
+# performance of recursive Make systems.
+""")
+        f.write('ifeq ($(LLVMBUILD_INCLUDE_DEPENDENCIES),1)\n')
+        f.write("# The dependencies for this Makefile fragment itself.\n")
+        f.write("%s: \\\n" % (mk_quote_string_for_target(output_path),))
+        for dep in dependencies:
+            f.write("\t%s \\\n" % (dep,))
+        f.write('\n')
+
+        # Generate dummy rules for each of the dependencies, so that things
+        # continue to work correctly if any of those files are moved or removed.
+        f.write("""\
+# The dummy targets to allow proper regeneration even when files are moved or
+# removed.
+""")
+        for dep in dependencies:
+            f.write("%s:\n" % (mk_quote_string_for_target(dep),))
+        f.write('endif\n')
+
+        f.close()
+
+def add_magic_target_components(parser, project, opts):
+    """add_magic_target_components(project, opts) -> None
+
+    Add the "magic" target based components to the project, which can only be
+    determined based on the target configuration options.
+
+    This currently is responsible for populating the required_libraries list of
+    the "all-targets", "Native", "NativeCodeGen", and "Engine" components.
+    """
+
+    # Determine the available targets.
+    available_targets = dict((ci.name,ci)
+                             for ci in project.component_infos
+                             if ci.type_name == 'TargetGroup')
+
+    # Find the configured native target.
+
+    # We handle a few special cases of target names here for historical
+    # reasons, as these are the names configure currently comes up with.
+    native_target_name = { 'x86' : 'X86',
+                           'x86_64' : 'X86',
+                           'Unknown' : None }.get(opts.native_target,
+                                                  opts.native_target)
+    if native_target_name is None:
+        native_target = None
+    else:
+        native_target = available_targets.get(native_target_name)
+        if native_target is None:
+            parser.error("invalid native target: %r (not in project)" % (
+                    opts.native_target,))
+        if native_target.type_name != 'TargetGroup':
+            parser.error("invalid native target: %r (not a target)" % (
+                    opts.native_target,))
+
+    # Find the list of targets to enable.
+    if opts.enable_targets is None:
+        enable_targets = available_targets.values()
+    else:
+        # We support both space separated and semi-colon separated lists.
+        if opts.enable_targets == '':
+            enable_target_names = []
+        elif ' ' in opts.enable_targets:
+            enable_target_names = opts.enable_targets.split()
+        else:
+            enable_target_names = opts.enable_targets.split(';')
+
+        enable_targets = []
+        for name in enable_target_names:
+            target = available_targets.get(name)
+            if target is None:
+                parser.error("invalid target to enable: %r (not in project)" % (
+                        name,))
+            if target.type_name != 'TargetGroup':
+                parser.error("invalid target to enable: %r (not a target)" % (
+                        name,))
+            enable_targets.append(target)
+
+    # Find the special library groups we are going to populate. We enforce that
+    # these appear in the project (instead of just adding them) so that they at
+    # least have an explicit representation in the project LLVMBuild files (and
+    # comments explaining how they are populated).
+    def find_special_group(name):
+        info = info_map.get(name)
+        if info is None:
+            fatal("expected project to contain special %r component" % (
+                    name,))
+
+        if info.type_name != 'LibraryGroup':
+            fatal("special component %r should be a LibraryGroup" % (
+                    name,))
+
+        if info.required_libraries:
+            fatal("special component %r must have empty %r list" % (
+                    name, 'required_libraries'))
+        if info.add_to_library_groups:
+            fatal("special component %r must have empty %r list" % (
+                    name, 'add_to_library_groups'))
+
+        info._is_special_group = True
+        return info
+
+    info_map = dict((ci.name, ci) for ci in project.component_infos)
+    all_targets = find_special_group('all-targets')
+    native_group = find_special_group('Native')
+    native_codegen_group = find_special_group('NativeCodeGen')
+    engine_group = find_special_group('Engine')
+
+    # Set the enabled bit in all the target groups, and append to the
+    # all-targets list.
+    for ci in enable_targets:
+        all_targets.required_libraries.append(ci.name)
+        ci.enabled = True
+
+    # If we have a native target, then that defines the native and
+    # native_codegen libraries.
+    if native_target and native_target.enabled:
+        native_group.required_libraries.append(native_target.name)
+        native_codegen_group.required_libraries.append(
+            '%sCodeGen' % native_target.name)
+
+    # If we have a native target with a JIT, use that for the engine. Otherwise,
+    # use the interpreter.
+    if native_target and native_target.enabled and native_target.has_jit:
+        engine_group.required_libraries.append('MCJIT')
+        engine_group.required_libraries.append(native_group.name)
+    else:
+        engine_group.required_libraries.append('Interpreter')
+
 def main():
     from optparse import OptionParser, OptionGroup
     parser = OptionParser("usage: %prog [options]")
-    parser.add_option("", "--source-root", dest="source_root", metavar="PATH",
+
+    group = OptionGroup(parser, "Input Options")
+    group.add_option("", "--source-root", dest="source_root", metavar="PATH",
                       help="Path to the LLVM source (inferred if not given)",
                       action="store", default=None)
-    parser.add_option("", "--print-tree", dest="print_tree",
-                      help="Print out the project component tree [%default]",
-                      action="store_true", default=False)
-    parser.add_option("", "--write-llvmbuild", dest="write_llvmbuild",
+    group.add_option("", "--llvmbuild-source-root",
+                     dest="llvmbuild_source_root",
+                     help=(
+            "If given, an alternate path to search for LLVMBuild.txt files"),
+                     action="store", default=None, metavar="PATH")
+    group.add_option("", "--build-root", dest="build_root", metavar="PATH",
+                      help="Path to the build directory (if needed) [%default]",
+                      action="store", default=None)
+    parser.add_option_group(group)
+
+    group = OptionGroup(parser, "Output Options")
+    group.add_option("", "--print-tree", dest="print_tree",
+                     help="Print out the project component tree [%default]",
+                     action="store_true", default=False)
+    group.add_option("", "--write-llvmbuild", dest="write_llvmbuild",
                       help="Write out the LLVMBuild.txt files to PATH",
                       action="store", default=None, metavar="PATH")
-    parser.add_option("", "--write-library-table",
-                      dest="write_library_table", metavar="PATH",
-                      help="Write the C++ library dependency table to PATH",
+    group.add_option("", "--write-library-table",
+                     dest="write_library_table", metavar="PATH",
+                     help="Write the C++ library dependency table to PATH",
+                     action="store", default=None)
+    group.add_option("", "--write-cmake-fragment",
+                     dest="write_cmake_fragment", metavar="PATH",
+                     help="Write the CMake project information to PATH",
+                     action="store", default=None)
+    group.add_option("", "--write-cmake-exports-fragment",
+                     dest="write_cmake_exports_fragment", metavar="PATH",
+                     help="Write the CMake exports information to PATH",
+                     action="store", default=None)
+    group.add_option("", "--write-make-fragment",
+                      dest="write_make_fragment", metavar="PATH",
+                     help="Write the Makefile project information to PATH",
+                     action="store", default=None)
+    group.add_option("", "--configure-target-def-file",
+                     dest="configure_target_def_files",
+                     help="""Configure the given file at SUBPATH (relative to
+the inferred or given source root, and with a '.in' suffix) by replacing certain
+substitution variables with lists of targets that support certain features (for
+example, targets with AsmPrinters) and write the result to the build root (as
+given by --build-root) at the same SUBPATH""",
+                     metavar="SUBPATH", action="append", default=None)
+    parser.add_option_group(group)
+
+    group = OptionGroup(parser, "Configuration Options")
+    group.add_option("", "--native-target",
+                      dest="native_target", metavar="NAME",
+                      help=("Treat the named target as the 'native' one, if "
+                            "given [%default]"),
                       action="store", default=None)
-    parser.add_option("", "--llvmbuild-source-root",
-                      dest="llvmbuild_source_root",
-                      help=(
-            "If given, an alternate path to search for LLVMBuild.txt files"),
-                      action="store", default=None, metavar="PATH")
+    group.add_option("", "--enable-targets",
+                      dest="enable_targets", metavar="NAMES",
+                      help=("Enable the given space or semi-colon separated "
+                            "list of targets, or all targets if not present"),
+                      action="store", default=None)
+    group.add_option("", "--enable-optional-components",
+                      dest="optional_components", metavar="NAMES",
+                      help=("Enable the given space or semi-colon separated "
+                            "list of optional components"),
+                      action="store", default="")
+    parser.add_option_group(group)
+
     (opts, args) = parser.parse_args()
 
     # Determine the LLVM source path, if not given.
     source_root = opts.source_root
     if source_root:
-        if not os.path.exists(os.path.join(source_root, 'lib', 'VMCore',
+        if not os.path.exists(os.path.join(source_root, 'lib', 'IR',
                                            'Function.cpp')):
             parser.error('invalid LLVM source root: %r' % source_root)
     else:
@@ -290,7 +880,7 @@ def main():
         llvm_build_path = os.path.dirname(llvmbuild_path)
         utils_path = os.path.dirname(llvm_build_path)
         source_root = os.path.dirname(utils_path)
-        if not os.path.exists(os.path.join(source_root, 'lib', 'VMCore',
+        if not os.path.exists(os.path.join(source_root, 'lib', 'IR',
                                            'Function.cpp')):
             parser.error('unable to infer LLVM source root, please specify')
 
@@ -299,6 +889,12 @@ def main():
     project_info = LLVMProjectInfo.load_from_path(
         source_root, llvmbuild_source_root)
 
+    # Add the magic target based components.
+    add_magic_target_components(parser, project_info, opts)
+
+    # Validate the project component info.
+    project_info.validate_components()
+
     # Print the component tree, if requested.
     if opts.print_tree:
         project_info.print_tree()
@@ -308,9 +904,57 @@ def main():
     if opts.write_llvmbuild:
         project_info.write_components(opts.write_llvmbuild)
 
-    # Write out the required librariy, if requested.
+    # Write out the required library table, if requested.
     if opts.write_library_table:
-        project_info.write_library_table(opts.write_library_table)
+        project_info.write_library_table(opts.write_library_table,
+                                         opts.optional_components)
+
+    # Write out the make fragment, if requested.
+    if opts.write_make_fragment:
+        project_info.write_make_fragment(opts.write_make_fragment)
+
+    # Write out the cmake fragment, if requested.
+    if opts.write_cmake_fragment:
+        project_info.write_cmake_fragment(opts.write_cmake_fragment,
+                                          opts.optional_components)
+    if opts.write_cmake_exports_fragment:
+        project_info.write_cmake_exports_fragment(opts.write_cmake_exports_fragment,
+                                                  opts.optional_components)
+
+    # Configure target definition files, if requested.
+    if opts.configure_target_def_files:
+        # Verify we were given a build root.
+        if not opts.build_root:
+            parser.error("must specify --build-root when using "
+                         "--configure-target-def-file")
+
+        # Create the substitution list.
+        available_targets = [ci for ci in project_info.component_infos
+                             if ci.type_name == 'TargetGroup']
+        substitutions = [
+            ("@LLVM_ENUM_TARGETS@",
+             ' '.join('LLVM_TARGET(%s)' % ci.name
+                      for ci in available_targets)),
+            ("@LLVM_ENUM_ASM_PRINTERS@",
+             ' '.join('LLVM_ASM_PRINTER(%s)' % ci.name
+                      for ci in available_targets
+                      if ci.has_asmprinter)),
+            ("@LLVM_ENUM_ASM_PARSERS@",
+             ' '.join('LLVM_ASM_PARSER(%s)' % ci.name
+                      for ci in available_targets
+                      if ci.has_asmparser)),
+            ("@LLVM_ENUM_DISASSEMBLERS@",
+             ' '.join('LLVM_DISASSEMBLER(%s)' % ci.name
+                      for ci in available_targets
+                      if ci.has_disassembler))]
+
+        # Configure the given files.
+        for subpath in opts.configure_target_def_files:
+            inpath = os.path.join(source_root, subpath + '.in')
+            outpath = os.path.join(opts.build_root, subpath)
+            result = configutil.configure_file(inpath, outpath, substitutions)
+            if not result:
+                note("configured file %r hasn't changed" % outpath)
 
 if __name__=='__main__':
     main()