From 1ad92131abbed3d2992d5996969274a8e1ae9a6b Mon Sep 17 00:00:00 2001
From: Daniel Dunbar <daniel@zuster.org>
Date: Thu, 10 Nov 2011 19:59:35 +0000
Subject: Revert r144300 "llvm-config: Replace with C++ version (was
 llvm-config-2).", which didn't appear ready for prime time.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144309 91177308-0d34-0410-b5e6-96231b3b80d8
---
 CMakeLists.txt                            |   2 +-
 Makefile                                  |   6 +-
 Makefile.rules                            |   7 +-
 configure                                 |   2 +-
 tools/CMakeLists.txt                      |  11 +-
 tools/Makefile                            |   2 +-
 tools/llvm-config-2/BuildVariables.inc.in |  26 ++
 tools/llvm-config-2/CMakeLists.txt        |  41 +++
 tools/llvm-config-2/Makefile              |  57 ++++
 tools/llvm-config-2/llvm-config.cpp       | 324 +++++++++++++++++++++
 tools/llvm-config/BuildVariables.inc.in   |  26 --
 tools/llvm-config/CMakeLists.txt          | 151 ++++++++--
 tools/llvm-config/Makefile                |  92 ++++--
 tools/llvm-config/find-cycles.pl          | 170 +++++++++++
 tools/llvm-config/llvm-config.cpp         | 324 ---------------------
 tools/llvm-config/llvm-config.in.in       | 466 ++++++++++++++++++++++++++++++
 16 files changed, 1288 insertions(+), 419 deletions(-)
 create mode 100644 tools/llvm-config-2/BuildVariables.inc.in
 create mode 100644 tools/llvm-config-2/CMakeLists.txt
 create mode 100644 tools/llvm-config-2/Makefile
 create mode 100644 tools/llvm-config-2/llvm-config.cpp
 delete mode 100644 tools/llvm-config/BuildVariables.inc.in
 create mode 100755 tools/llvm-config/find-cycles.pl
 delete mode 100644 tools/llvm-config/llvm-config.cpp
 create mode 100644 tools/llvm-config/llvm-config.in.in

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6dd8169ebc..5d36f5fc10 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -230,7 +230,7 @@ endif()
 
 set(LLVMBUILDTOOL "${LLVM_MAIN_SRC_DIR}/utils/llvm-build/llvm-build")
 set(LLVMCONFIGLIBRARYDEPENDENCIESINC
-  "${LLVM_BINARY_DIR}/tools/llvm-config/LibraryDependencies.inc")
+  "${LLVM_BINARY_DIR}/tools/llvm-config-2/LibraryDependencies.inc")
 set(LLVMBUILDCMAKEFRAG
   "${LLVM_BINARY_DIR}/LLVMBuild.cmake")
 message(STATUS "Constructing LLVMBuild project information")
diff --git a/Makefile b/Makefile
index 3590d5c6cf..dae41cf56a 100644
--- a/Makefile
+++ b/Makefile
@@ -10,12 +10,12 @@
 LEVEL := .
 
 # Top-Level LLVM Build Stages:
-#   0. Execute llvm-build, to construct llvm-config library dependencies.
 #   1. Build lib/Support and lib/TableGen, which are used by utils (tblgen).
 #   2. Build utils, which is used by VMCore.
 #   3. Build VMCore, which builds the Intrinsics.inc file used by libs.
-#   4. Build llvm-config, which determines inter-lib dependencies for tools.
-#   5. Build tools, runtime, docs.
+#   4. Build libs, which are needed by llvm-config.
+#   5. Build llvm-config, which determines inter-lib dependencies for tools.
+#   6. Build tools, runtime, docs.
 #
 # When cross-compiling, there are some things (tablegen) that need to
 # be build for the build system first.
diff --git a/Makefile.rules b/Makefile.rules
index b2132f11cb..78d1f97e14 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -79,7 +79,7 @@ LLVMBuildTool	:= $(PROJ_SRC_ROOT)/utils/llvm-build/llvm-build
 # The files we are going to generate using llvm-build.
 LLVMBuildMakeFrag := $(PROJ_OBJ_ROOT)/Makefile.llvmbuild
 LLVMConfigLibraryDependenciesInc := \
-	$(PROJ_OBJ_ROOT)/tools/llvm-config/LibraryDependencies.inc
+	$(PROJ_OBJ_ROOT)/tools/llvm-config-2/LibraryDependencies.inc
 
 # The rule to create the LLVMBuild Makefile fragment as well as the llvm-config
 # library table.
@@ -1006,16 +1006,11 @@ ifdef LINK_COMPONENTS
 
 # If LLVM_CONFIG doesn't exist, build it.  This can happen if you do a make
 # clean in tools, then do a make in tools (instead of at the top level).
-#
-# We don't want these targets when actually building the LLVM_CONFIG tool
-# itself, of course.
-ifneq ($(TOOLNAME),llvm-config)
 $(LLVM_CONFIG):
 	@echo "*** llvm-config doesn't exist - rebuilding it."
 	@$(MAKE) -C $(PROJ_OBJ_ROOT)/tools/llvm-config
 
 $(ToolDir)/$(strip $(TOOLNAME))$(EXEEXT): $(LLVM_CONFIG)
-endif
 
 ifeq ($(ENABLE_SHARED), 1)
 # We can take the "auto-import" feature to get rid of using dllimport.
diff --git a/configure b/configure
index 46182ff624..ae6be9d535 100755
--- a/configure
+++ b/configure
@@ -21065,7 +21065,7 @@ if test -f ${srcdir}/tools/clang/README.txt; then
 
 fi
 
-
+ac_config_files="$ac_config_files tools/llvm-config/llvm-config.in"
 
 
 ac_config_files="$ac_config_files bindings/ocaml/llvm/META.llvm"
diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index 46d08a4b17..28b36dcdfd 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -11,9 +11,16 @@ if( EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/polly/CMakeLists.txt )
 endif( EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/polly/CMakeLists.txt )
 
 if( NOT WIN32 OR MSYS OR CYGWIN )
-  # We currently require 'sed' to build llvm-config, so don't try to build it on
-  # pure Win32.
+  # It is useful to build llvm-config before the other tools, so we
+  # have a fresh LibDeps.txt for regenerating the hard-coded library
+  # dependencies. llvm-config/CMakeLists.txt takes care of this but we
+  # must keep llvm-config as the first entry on the list of tools to
+  # be built.
   add_subdirectory(llvm-config)
+
+  # We currently require 'sed' to build llvm-config-2, so don't try to build it
+  # on pure Win32.
+  add_subdirectory(llvm-config-2)
 endif()
 
 add_subdirectory(opt)
diff --git a/tools/Makefile b/tools/Makefile
index 2da3917781..278546bc16 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -34,7 +34,7 @@ PARALLEL_DIRS := opt llvm-as llvm-dis \
                  bugpoint llvm-bcanalyzer llvm-stub \
                  llvm-diff macho-dump llvm-objdump \
 	         llvm-rtdyld llvm-dwarfdump llvm-cov \
-	         llvm-size
+	         llvm-size llvm-config-2
 
 # Let users override the set of tools to build from the command line.
 ifdef ONLY_TOOLS
diff --git a/tools/llvm-config-2/BuildVariables.inc.in b/tools/llvm-config-2/BuildVariables.inc.in
new file mode 100644
index 0000000000..5969772c9d
--- /dev/null
+++ b/tools/llvm-config-2/BuildVariables.inc.in
@@ -0,0 +1,26 @@
+//===-- BuildVariables.inc.in - llvm-config build variables -*- C++ -*-----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is configured by the build system to define the variables
+// llvm-config wants to report to the user, but which can only be determined at
+// build time.
+//
+// The non .in variant of this file has been autogenerated by the LLVM build. Do
+// not edit!
+//
+//===----------------------------------------------------------------------===//
+
+#define LLVM_SRC_ROOT "@LLVM_SRC_ROOT@"
+#define LLVM_OBJ_ROOT "@LLVM_OBJ_ROOT@"
+#define LLVM_CPPFLAGS "@LLVM_CPPFLAGS@"
+#define LLVM_CFLAGS "@LLVM_CFLAGS@"
+#define LLVM_LDFLAGS "@LLVM_LDFLAGS@"
+#define LLVM_CXXFLAGS "@LLVM_CXXFLAGS@"
+#define LLVM_BUILDMODE "@LLVM_BUILDMODE@"
+#define LLVM_SYSTEM_LIBS "@LLVM_SYSTEM_LIBS@"
diff --git a/tools/llvm-config-2/CMakeLists.txt b/tools/llvm-config-2/CMakeLists.txt
new file mode 100644
index 0000000000..3c7169d382
--- /dev/null
+++ b/tools/llvm-config-2/CMakeLists.txt
@@ -0,0 +1,41 @@
+set(LLVM_LINK_COMPONENTS support)
+
+# We need to generate the BuildVariables.inc file containing values which are
+# only defined when under certain build modes. Unfortunately, that precludes
+# doing this inside CMake so we have to shell out to sed. For now, that means we
+# can't expect to build llvm-config on Window.s
+set(BUILDVARIABLES_SRCPATH ${CMAKE_CURRENT_SOURCE_DIR}/BuildVariables.inc.in)
+set(BUILDVARIABLES_OBJPATH ${CMAKE_CURRENT_BINARY_DIR}/BuildVariables.inc)
+set(SEDSCRIPT_OBJPATH ${CMAKE_CURRENT_BINARY_DIR}/BuildVariables.configure.sed)
+
+# Compute the substitution values for various items.
+get_system_libs(LLVM_SYSTEM_LIBS_LIST)
+foreach(l ${LLVM_SYSTEM_LIBS_LIST})
+  set(SYSTEM_LIBS ${SYSTEM_LIBS} "-l${l}")
+endforeach()
+set(C_FLGS "${CMAKE_C_FLAGS} ${CMAKE_C_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
+set(CXX_FLGS "${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
+set(CPP_FLGS "${CMAKE_CPP_FLAGS} ${CMAKE_CPP_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
+
+add_custom_command(OUTPUT ${BUILDVARIABLES_OBJPATH}
+  COMMAND echo s!@LLVM_SRC_ROOT@!${LLVM_MAIN_SRC_DIR}! > ${SEDSCRIPT_OBJPATH}
+  COMMAND echo s!@LLVM_OBJ_ROOT@!${LLVM_BINARY_DIR}! >> ${SEDSCRIPT_OBJPATH}
+  COMMAND echo s!@LLVM_CPPFLAGS@!${CPP_FLGS}! >> ${SEDSCRIPT_OBJPATH}
+  COMMAND echo s!@LLVM_CFLAGS@!${C_FLGS}! >> ${SEDSCRIPT_OBJPATH}
+  COMMAND echo s!@LLVM_CXXFLAGS@!${CXX_FLGS}! >> ${SEDSCRIPT_OBJPATH}
+  # TODO: Use general flags for linking! not just for shared libs:
+  COMMAND echo s!@LLVM_LDFLAGS@!${CMAKE_SHARED_LINKER_FLAGS}! >> ${SEDSCRIPT_OBJPATH}
+  COMMAND echo s!@LLVM_BUILDMODE@!${CMAKE_BUILD_TYPE}! >> ${SEDSCRIPT_OBJPATH}
+  COMMAND echo s!@LLVM_SYSTEM_LIBS@!${SYSTEM_LIBS}! >> ${SEDSCRIPT_OBJPATH}
+  COMMAND sed -f ${SEDSCRIPT_OBJPATH} < ${BUILDVARIABLES_SRCPATH} > ${BUILDVARIABLES_OBJPATH}
+  VERBATIM
+  COMMENT "Building BuildVariables.inc include."
+  )
+
+# Add the llvm-config tool.
+add_llvm_tool(llvm-config-2
+  llvm-config.cpp
+  )
+
+# Add the dependency on the generation step.
+add_file_dependencies(${CMAKE_CURRENT_SOURCE_DIR}/llvm-config.cpp ${BUILDVARIABLES_OBJPATH})
diff --git a/tools/llvm-config-2/Makefile b/tools/llvm-config-2/Makefile
new file mode 100644
index 0000000000..08e084429d
--- /dev/null
+++ b/tools/llvm-config-2/Makefile
@@ -0,0 +1,57 @@
+##===- tools/llvm-config/Makefile---------------------------*- Makefile -*-===##
+# 
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+# 
+##===----------------------------------------------------------------------===##
+
+LEVEL := ../..
+TOOLNAME := llvm-config-2
+USEDLIBS := LLVMSupport.a
+
+# We generate sources in the build directory, make sure it is in the include
+# paths.
+INCLUDE_BUILD_DIR := 1
+
+# This tool has no plugins, optimize startup time.
+TOOL_NO_EXPORTS := 1
+
+# Note that we have to use lazy expansion here.
+BUILDVARIABLES_SRCPATH = $(PROJ_SRC_ROOT)/tools/$(TOOLNAME)/BuildVariables.inc.in
+BUILDVARIABLES_OBJPATH = $(ObjDir)/BuildVariables.inc
+BUILT_SOURCES = $(BUILDVARIABLES_OBJPATH)
+
+include $(LEVEL)/Makefile.common
+
+# Combine preprocessor flags (except for -I) and CXX flags.
+SUB_CPPFLAGS := ${CPP.BaseFlags}
+SUB_CFLAGS   := ${CPP.BaseFlags} ${C.Flags}
+SUB_CXXFLAGS := ${CPP.BaseFlags} ${CXX.Flags}
+
+# This is blank for now.  We need to be careful about adding stuff here:
+# LDFLAGS tend not to be portable, and we don't currently require the
+# user to use libtool when linking against LLVM.
+SUB_LDFLAGS :=
+
+$(ObjDir)/BuildVariables.inc: $(BUILDVARIABLES_SRCPATH) Makefile $(ObjDir)/.dir
+	$(Echo) "Building llvm-config BuildVariables.inc file."
+	$(Verb) $(ECHO) 's/@LLVM_SRC_ROOT@/$(subst /,\/,$(LLVM_SRC_ROOT))/' \
+	  > temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_OBJ_ROOT@/$(subst /,\/,$(LLVM_OBJ_ROOT))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_CPPFLAGS@/$(subst /,\/,$(SUB_CPPFLAGS))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_CFLAGS@/$(subst /,\/,$(SUB_CFLAGS))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_CXXFLAGS@/$(subst /,\/,$(SUB_CXXFLAGS))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_LDFLAGS@/$(subst /,\/,$(SUB_LDFLAGS))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_BUILDMODE@/$(subst /,\/,$(BuildMode))/' \
+	  >> temp.sed
+	$(Verb) $(ECHO) 's/@LLVM_SYSTEM_LIBS@/$(subst /,\/,$(LIBS))/' \
+	  >> temp.sed
+	$(Verb) $(SED) -f temp.sed < $< > $@
+	$(Verb) $(RM) temp.sed
diff --git a/tools/llvm-config-2/llvm-config.cpp b/tools/llvm-config-2/llvm-config.cpp
new file mode 100644
index 0000000000..30ace56f4c
--- /dev/null
+++ b/tools/llvm-config-2/llvm-config.cpp
@@ -0,0 +1,324 @@
+//===-- llvm-config.cpp - LLVM project configuration utility --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This tool encapsulates information about an LLVM project configuration for
+// use by other project's build environments (to determine installed path,
+// available features, required libraries, etc.).
+//
+// Note that although this tool *may* be used by some parts of LLVM's build
+// itself (i.e., the Makefiles use it to compute required libraries when linking
+// tools), this tool is primarily designed to support external projects.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/Config/config.h"
+#include "llvm/Config/llvm-config.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cstdlib>
+#include <set>
+#include <vector>
+
+using namespace llvm;
+
+// Include the build time variables we can report to the user. This is generated
+// at build time from the BuildVariables.inc.in file by the build system.
+#include "BuildVariables.inc"
+
+// Include the component table. This creates an array of struct
+// AvailableComponent entries, which record the component name, library name,
+// and required components for all of the available libraries.
+//
+// Not all components define a library, we also use "library groups" as a way to
+// create entries for pseudo groups like x86 or all-targets.
+#include "LibraryDependencies.inc"
+
+/// \brief Traverse a single component adding to the topological ordering in
+/// \arg RequiredLibs.
+///
+/// \param Name - The component to traverse.
+/// \param ComponentMap - A prebuilt map of component names to descriptors.
+/// \param VisitedComponents [in] [out] - The set of already visited components.
+/// \param RequiredLibs [out] - The ordered list of required libraries.
+static void VisitComponent(StringRef Name,
+                           const StringMap<AvailableComponent*> &ComponentMap,
+                           std::set<AvailableComponent*> &VisitedComponents,
+                           std::vector<StringRef> &RequiredLibs) {
+  // Lookup the component.
+  AvailableComponent *AC = ComponentMap.lookup(Name);
+  assert(AC && "Invalid component name!");
+
+  // Add to the visited table.
+  if (!VisitedComponents.insert(AC).second) {
+    // We are done if the component has already been visited.
+    return;
+  }
+
+  // Otherwise, visit all the dependencies.
+  for (unsigned i = 0; AC->RequiredLibraries[i]; ++i) {
+    VisitComponent(AC->RequiredLibraries[i], ComponentMap, VisitedComponents,
+                   RequiredLibs);
+  }
+
+  // Add to the required library list.
+  if (AC->Library)
+    RequiredLibs.push_back(AC->Library);
+}
+
+/// \brief Compute the list of required libraries for a given list of
+/// components, in an order suitable for passing to a linker (that is, libraries
+/// appear prior to their dependencies).
+///
+/// \param Components - The names of the components to find libraries for.
+/// \param RequiredLibs [out] - On return, the ordered list of libraries that
+/// are required to link the given components.
+void ComputeLibsForComponents(const std::vector<StringRef> &Components,
+                              std::vector<StringRef> &RequiredLibs) {
+  std::set<AvailableComponent*> VisitedComponents;
+
+  // Build a map of component names to information.
+  StringMap<AvailableComponent*> ComponentMap;
+  for (unsigned i = 0; i != array_lengthof(AvailableComponents); ++i) {
+    AvailableComponent *AC = &AvailableComponents[i];
+    ComponentMap[AC->Name] = AC;
+  }
+
+  // Visit the components.
+  for (unsigned i = 0, e = Components.size(); i != e; ++i) {
+    // Users are allowed to provide mixed case component names.
+    std::string ComponentLower = Components[i].lower();
+
+    // Validate that the user supplied a valid component name.
+    if (!ComponentMap.count(ComponentLower)) {
+      llvm::errs() << "llvm-config: unknown component name: " << Components[i]
+                   << "\n";
+      exit(1);
+    }
+
+    VisitComponent(ComponentLower, ComponentMap, VisitedComponents,
+                   RequiredLibs);
+  }
+
+  // The list is now ordered with leafs first, we want the libraries to printed
+  // in the reverse order of dependency.
+  std::reverse(RequiredLibs.begin(), RequiredLibs.end());
+}
+
+/* *** */
+
+void usage() {
+  errs() << "\
+usage: llvm-config <OPTION>... [<COMPONENT>...]\n\
+\n\
+Get various configuration information needed to compile programs which use\n\
+LLVM.  Typically called from 'configure' scripts.  Examples:\n\
+  llvm-config --cxxflags\n\
+  llvm-config --ldflags\n\
+  llvm-config --libs engine bcreader scalaropts\n\
+\n\
+Options:\n\
+  --version         Print LLVM version.\n\
+  --prefix          Print the installation prefix.\n\
+  --src-root        Print the source root LLVM was built from.\n\
+  --obj-root        Print the object root used to build LLVM.\n\
+  --bindir          Directory containing LLVM executables.\n\
+  --includedir      Directory containing LLVM headers.\n\
+  --libdir          Directory containing LLVM libraries.\n\
+  --cppflags        C preprocessor flags for files that include LLVM headers.\n\
+  --cflags          C compiler flags for files that include LLVM headers.\n\
+  --cxxflags        C++ compiler flags for files that include LLVM headers.\n\
+  --ldflags         Print Linker flags.\n\
+  --libs            Libraries needed to link against LLVM components.\n\
+  --libnames        Bare library names for in-tree builds.\n\
+  --libfiles        Fully qualified library filenames for makefile depends.\n\
+  --components      List of all possible components.\n\
+  --targets-built   List of all targets currently built.\n\
+  --host-target     Target triple used to configure LLVM.\n\
+  --build-mode      Print build mode of LLVM tree (e.g. Debug or Release).\n\
+Typical components:\n\
+  all               All LLVM libraries (default).\n\
+  backend           Either a native backend or the C backend.\n\
+  engine            Either a native JIT or a bitcode interpreter.\n";
+  exit(1);
+}
+
+/// \brief Compute the path to the main executable.
+llvm::sys::Path GetExecutablePath(const char *Argv0) {
+  // This just needs to be some symbol in the binary; C++ doesn't
+  // allow taking the address of ::main however.
+  void *P = (void*) (intptr_t) GetExecutablePath;
+  return llvm::sys::Path::GetMainExecutable(Argv0, P);
+}
+
+int main(int argc, char **argv) {
+  std::vector<StringRef> Components;
+  bool PrintLibs = false, PrintLibNames = false, PrintLibFiles = false;
+  bool HasAnyOption = false;
+
+  // llvm-config is designed to support being run both from a development tree
+  // and from an installed path. We try and auto-detect which case we are in so
+  // that we can report the correct information when run from a development
+  // tree.
+  bool IsInDevelopmentTree, DevelopmentTreeLayoutIsCMakeStyle;
+  llvm::SmallString<256> CurrentPath(GetExecutablePath(argv[0]).str());
+  std::string CurrentExecPrefix;
+
+  // Create an absolute path, and pop up one directory (we expect to be inside a
+  // bin dir).
+  sys::fs::make_absolute(CurrentPath);
+  CurrentExecPrefix = sys::path::parent_path(
+    sys::path::parent_path(CurrentPath)).str();
+
+  // Check to see if we are inside a development tree by comparing to possible
+  // locations (prefix style or CMake style). This could be wrong in the face of
+  // symbolic links, but is good enough.
+  if (CurrentExecPrefix == std::string(LLVM_OBJ_ROOT) + "/" + LLVM_BUILDMODE) {
+    IsInDevelopmentTree = true;
+    DevelopmentTreeLayoutIsCMakeStyle = false;
+  } else if (CurrentExecPrefix == std::string(LLVM_OBJ_ROOT) + "/bin") {
+    IsInDevelopmentTree = true;
+    DevelopmentTreeLayoutIsCMakeStyle = true;
+  } else {
+    IsInDevelopmentTree = false;
+  }
+
+  // Compute various directory locations based on the derived location
+  // information.
+  std::string ActivePrefix, ActiveBinDir, ActiveIncludeDir, ActiveLibDir;
+  std::string ActiveIncludeOption;
+  if (IsInDevelopmentTree) {
+    ActivePrefix = CurrentExecPrefix;
+
+    // CMake organizes the products differently than a normal prefix style
+    // layout.
+    if (DevelopmentTreeLayoutIsCMakeStyle) {
+      ActiveIncludeDir = std::string(LLVM_OBJ_ROOT) + "/include";
+      ActiveBinDir = std::string(LLVM_OBJ_ROOT) + "/bin/" + LLVM_BUILDMODE;
+      ActiveLibDir = std::string(LLVM_OBJ_ROOT) + "/lib/" + LLVM_BUILDMODE;
+    } else {
+        ActiveIncludeDir = std::string(LLVM_OBJ_ROOT) + "/include";
+      ActiveBinDir = std::string(LLVM_OBJ_ROOT) + "/" + LLVM_BUILDMODE + "/bin";
+      ActiveLibDir = std::string(LLVM_OBJ_ROOT) + "/" + LLVM_BUILDMODE + "/lib";
+    }
+
+    // We need to include files from both the source and object trees.
+    ActiveIncludeOption = ("-I" + ActiveIncludeDir + " " +
+                           "-I" + LLVM_OBJ_ROOT + "/include");
+  } else {
+    ActivePrefix = CurrentExecPrefix;
+    ActiveIncludeDir = ActivePrefix + "/include";
+    ActiveBinDir = ActivePrefix + "/bin";
+    ActiveLibDir = ActivePrefix + "/lib";
+    ActiveIncludeOption = "-I" + ActiveIncludeDir;
+  }
+
+  raw_ostream &OS = outs();
+  for (int i = 1; i != argc; ++i) {
+    StringRef Arg = argv[i];
+
+    if (Arg.startswith("-")) {
+      HasAnyOption = true;
+      if (Arg == "--version") {
+        OS << PACKAGE_VERSION << '\n';
+      } else if (Arg == "--prefix") {
+        OS << ActivePrefix << '\n';
+      } else if (Arg == "--bindir") {
+        OS << ActiveBinDir << '\n';
+      } else if (Arg == "--includedir") {
+        OS << ActiveIncludeDir << '\n';
+      } else if (Arg == "--libdir") {
+        OS << ActiveLibDir << '\n';
+      } else if (Arg == "--cppflags") {
+        OS << ActiveIncludeOption << ' ' << LLVM_CPPFLAGS << '\n';
+      } else if (Arg == "--cflags") {
+        OS << ActiveIncludeOption << ' ' << LLVM_CFLAGS << '\n';
+      } else if (Arg == "--cxxflags") {
+        OS << ActiveIncludeOption << ' ' << LLVM_CXXFLAGS << '\n';
+      } else if (Arg == "--ldflags") {
+        OS << "-L" << ActiveLibDir << ' ' << LLVM_LDFLAGS
+           << ' ' << LLVM_SYSTEM_LIBS << '\n';
+      } else if (Arg == "--libs") {
+        PrintLibs = true;
+      } else if (Arg == "--libnames") {
+        PrintLibNames = true;
+      } else if (Arg == "--libfiles") {
+        PrintLibFiles = true;
+      } else if (Arg == "--components") {
+        for (unsigned j = 0; j != array_lengthof(AvailableComponents); ++j) {
+          OS << ' ';
+          OS << AvailableComponents[j].Name;
+        }
+        OS << '\n';
+      } else if (Arg == "--targets-built") {
+        bool First = true;
+        for (TargetRegistry::iterator I = TargetRegistry::begin(),
+               E = TargetRegistry::end(); I != E; First = false, ++I) {
+          if (!First)
+            OS << ' ';
+          OS << I->getName();
+        }
+        OS << '\n';
+      } else if (Arg == "--host-target") {
+        OS << LLVM_DEFAULT_TARGET_TRIPLE << '\n';
+      } else if (Arg == "--build-mode") {
+        OS << LLVM_BUILDMODE << '\n';
+      } else if (Arg == "--obj-root") {
+        OS << LLVM_OBJ_ROOT << '\n';
+      } else if (Arg == "--src-root") {
+        OS << LLVM_SRC_ROOT << '\n';
+      } else {
+        usage();
+      }
+    } else {
+      Components.push_back(Arg);
+    }
+  }
+
+  if (!HasAnyOption)
+    usage();
+
+  if (PrintLibs || PrintLibNames || PrintLibFiles) {
+    // Construct the list of all the required libraries.
+    std::vector<StringRef> RequiredLibs;
+    ComputeLibsForComponents(Components, RequiredLibs);
+
+    for (unsigned i = 0, e = RequiredLibs.size(); i != e; ++i) {
+      StringRef Lib = RequiredLibs[i];
+      if (i)
+        OS << ' ';
+
+      if (PrintLibNames) {
+        OS << Lib;
+      } else if (PrintLibFiles) {
+        OS << ActiveLibDir << '/' << Lib;
+      } else if (PrintLibs) {
+        // If this is a typical library name, include it using -l.
+        if (Lib.startswith("lib") && Lib.endswith(".a")) {
+          OS << "-l" << Lib.slice(3, Lib.size()-2);
+          continue;
+        }
+
+        // Otherwise, print the full path.
+        OS << ActiveLibDir << '/' << Lib;
+      }
+    }
+    OS << '\n';
+  } else if (!Components.empty()) {
+    errs() << "llvm-config: error: components given, but unused\n\n";
+    usage();
+  }
+
+  return 0;
+}
diff --git a/tools/llvm-config/BuildVariables.inc.in b/tools/llvm-config/BuildVariables.inc.in
deleted file mode 100644
index 5969772c9d..0000000000
--- a/tools/llvm-config/BuildVariables.inc.in
+++ /dev/null
@@ -1,26 +0,0 @@
-//===-- BuildVariables.inc.in - llvm-config build variables -*- C++ -*-----===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file is configured by the build system to define the variables
-// llvm-config wants to report to the user, but which can only be determined at
-// build time.
-//
-// The non .in variant of this file has been autogenerated by the LLVM build. Do
-// not edit!
-//
-//===----------------------------------------------------------------------===//
-
-#define LLVM_SRC_ROOT "@LLVM_SRC_ROOT@"
-#define LLVM_OBJ_ROOT "@LLVM_OBJ_ROOT@"
-#define LLVM_CPPFLAGS "@LLVM_CPPFLAGS@"
-#define LLVM_CFLAGS "@LLVM_CFLAGS@"
-#define LLVM_LDFLAGS "@LLVM_LDFLAGS@"
-#define LLVM_CXXFLAGS "@LLVM_CXXFLAGS@"
-#define LLVM_BUILDMODE "@LLVM_BUILDMODE@"
-#define LLVM_SYSTEM_LIBS "@LLVM_SYSTEM_LIBS@"
diff --git a/tools/llvm-config/CMakeLists.txt b/tools/llvm-config/CMakeLists.txt
index ed26ba9555..53f00846b7 100644
--- a/tools/llvm-config/CMakeLists.txt
+++ b/tools/llvm-config/CMakeLists.txt
@@ -1,41 +1,138 @@
-set(LLVM_LINK_COMPONENTS support)
+include(TestBigEndian)
 
-# We need to generate the BuildVariables.inc file containing values which are
-# only defined when under certain build modes. Unfortunately, that precludes
-# doing this inside CMake so we have to shell out to sed. For now, that means we
-# can't expect to build llvm-config on Window.s
-set(BUILDVARIABLES_SRCPATH ${CMAKE_CURRENT_SOURCE_DIR}/BuildVariables.inc.in)
-set(BUILDVARIABLES_OBJPATH ${CMAKE_CURRENT_BINARY_DIR}/BuildVariables.inc)
-set(SEDSCRIPT_OBJPATH ${CMAKE_CURRENT_BINARY_DIR}/BuildVariables.configure.sed)
+include(FindPerl)
+if( NOT PERL_FOUND )
+  message(FATAL_ERROR "Perl required but not found!")
+endif( NOT PERL_FOUND )
+
+set(PERL ${PERL_EXECUTABLE})
+set(VERSION PACKAGE_VERSION)
+set(PREFIX ${CMAKE_INSTALL_PREFIX})
+set(abs_top_srcdir ${LLVM_MAIN_SRC_DIR})
+set(abs_top_builddir ${LLVM_BINARY_DIR})
+execute_process(COMMAND date
+  OUTPUT_VARIABLE LLVM_CONFIGTIME
+  OUTPUT_STRIP_TRAILING_WHITESPACE)
+# LLVM_ON_UNIX and LLVM_ON_WIN32 already set.
+# those are set to blank by `autoconf' on MinGW, so it seems they are not required:
+#set(LLVMGCCDIR "")
+#set(LLVMGCC "")
+#set(LLVMGXX "")
+test_big_endian(IS_BIG_ENDIAN)
+if( IS_BIG_ENDIAN )
+  set(ENDIAN "big")
+else( IS_BIG_ENDIAN )
+  set(ENDIAN "little")
+endif( IS_BIG_ENDIAN )
+set(SHLIBEXT ${LTDL_SHLIB_EXT})
+#EXEEXT already set.
+set(OS "${CMAKE_SYSTEM}")
+set(target "${TARGET_TRIPLE}")
+set(ARCH "${LLVM_NATIVE_ARCH}")
 
-# Compute the substitution values for various items.
 get_system_libs(LLVM_SYSTEM_LIBS_LIST)
 foreach(l ${LLVM_SYSTEM_LIBS_LIST})
-  set(SYSTEM_LIBS ${SYSTEM_LIBS} "-l${l}")
+  set(LLVM_SYSTEM_LIBS ${LLVM_SYSTEM_LIBS} "-l${l}")
 endforeach()
+
+foreach(c ${LLVM_TARGETS_TO_BUILD})
+  set(TARGETS_BUILT "${TARGETS_BUILT} ${c}")
+endforeach(c)
+set(TARGETS_TO_BUILD ${TARGETS_BUILT})
+set(TARGET_HAS_JIT "1")  # TODO
+
+# Avoids replacement at config-time:
+set(LLVM_CPPFLAGS "@LLVM_CPPFLAGS@")
+set(LLVM_CFLAGS "@LLVM_CFLAGS@")
+set(LLVM_CXXFLAGS "@LLVM_CXXFLAGS@")
+set(LLVM_LDFLAGS "@LLVM_LDFLAGS@")
+set(LIBS "@LIBS@")
+set(LLVM_BUILDMODE "@LLVM_BUILDMODE@")
+set(LLVM_OBJ_SUFFIX "@LLVM_OBJ_SUFFIX@")
+
+configure_file(
+  ${CMAKE_CURRENT_SOURCE_DIR}/llvm-config.in.in
+  ${CMAKE_CURRENT_BINARY_DIR}/llvm-config.in
+  @ONLY
+)
+
+set(LIBDEPS LibDeps.txt)
+set(LIBDEPS_TMP LibDeps.txt.tmp)
+set(FINAL_LIBDEPS FinalLibDeps.txt)
+set(LLVM_CONFIG ${LLVM_TOOLS_BINARY_DIR}/llvm-config)
+set(LLVM_CONFIG_IN ${CMAKE_CURRENT_BINARY_DIR}/llvm-config.in)
+
+if( CMAKE_CROSSCOMPILING )
+  set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM ONLY)
+endif()
+
+find_program(NM_PATH nm PATH_SUFFIXES /bin)
+
+if( NOT NM_PATH )
+  message(FATAL_ERROR "`nm' not found")
+endif()
+
+get_property(llvm_libs GLOBAL PROPERTY LLVM_LIBS)
+
+add_custom_command(OUTPUT ${LIBDEPS_TMP}
+  COMMAND ${PERL_EXECUTABLE} ${LLVM_MAIN_SRC_DIR}/utils/GenLibDeps.pl -flat ${CMAKE_ARCHIVE_OUTPUT_DIRECTORY}/${CMAKE_CFG_INTDIR} ${NM_PATH} > ${LIBDEPS_TMP}
+  DEPENDS ${llvm_libs}
+  COMMENT "Regenerating ${LIBDEPS_TMP}")
+
+add_custom_command(OUTPUT ${LIBDEPS}
+  COMMAND ${CMAKE_COMMAND} -E copy_if_different ${LIBDEPS_TMP} ${LIBDEPS}
+  DEPENDS ${LIBDEPS_TMP}
+  COMMENT "Updating ${LIBDEPS} if necessary...")
+
+# This must stop the build if find-cycles.pl returns error:
+add_custom_command(OUTPUT ${FINAL_LIBDEPS}
+  COMMAND ${CMAKE_COMMAND} -E remove -f ${FINAL_LIBDEPS} ${FINAL_LIBDEPS}.tmp
+  COMMAND ${PERL_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/find-cycles.pl < ${LIBDEPS} > ${FINAL_LIBDEPS}.tmp
+  COMMAND ${CMAKE_COMMAND} -E copy ${FINAL_LIBDEPS}.tmp ${FINAL_LIBDEPS}
+  DEPENDS ${LIBDEPS}
+  COMMENT "Checking for cyclic dependencies between LLVM libraries.")
+
 set(C_FLGS "${CMAKE_C_FLAGS} ${CMAKE_C_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
 set(CXX_FLGS "${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
 set(CPP_FLGS "${CMAKE_CPP_FLAGS} ${CMAKE_CPP_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}")
 
-add_custom_command(OUTPUT ${BUILDVARIABLES_OBJPATH}
-  COMMAND echo s!@LLVM_SRC_ROOT@!${LLVM_MAIN_SRC_DIR}! > ${SEDSCRIPT_OBJPATH}
-  COMMAND echo s!@LLVM_OBJ_ROOT@!${LLVM_BINARY_DIR}! >> ${SEDSCRIPT_OBJPATH}
-  COMMAND echo s!@LLVM_CPPFLAGS@!${CPP_FLGS}! >> ${SEDSCRIPT_OBJPATH}
-  COMMAND echo s!@LLVM_CFLAGS@!${C_FLGS}! >> ${SEDSCRIPT_OBJPATH}
-  COMMAND echo s!@LLVM_CXXFLAGS@!${CXX_FLGS}! >> ${SEDSCRIPT_OBJPATH}
+# We don't want certain flags on the output of
+# llvm-config --cflags --cxxflags
+macro(remove_option_from_llvm_config option)
+  llvm_replace_compiler_option(C_FLGS "${option}" "")
+  llvm_replace_compiler_option(CXX_FLGS "${option}" "")
+  llvm_replace_compiler_option(CPP_FLGS "${option}" "")
+endmacro(remove_option_from_llvm_config)
+remove_option_from_llvm_config("-pedantic")
+remove_option_from_llvm_config("-Wall")
+remove_option_from_llvm_config("-W")
+
+add_custom_command(OUTPUT ${LLVM_CONFIG}
+  COMMAND echo s!@LLVM_CPPFLAGS@!${CPP_FLGS}! > temp.sed
+  COMMAND echo s!@LLVM_CFLAGS@!${C_FLGS}! >> temp.sed
+  COMMAND echo s!@LLVM_CXXFLAGS@!${CXX_FLGS}! >> temp.sed
   # TODO: Use general flags for linking! not just for shared libs:
-  COMMAND echo s!@LLVM_LDFLAGS@!${CMAKE_SHARED_LINKER_FLAGS}! >> ${SEDSCRIPT_OBJPATH}
-  COMMAND echo s!@LLVM_BUILDMODE@!${CMAKE_BUILD_TYPE}! >> ${SEDSCRIPT_OBJPATH}
-  COMMAND echo s!@LLVM_SYSTEM_LIBS@!${SYSTEM_LIBS}! >> ${SEDSCRIPT_OBJPATH}
-  COMMAND sed -f ${SEDSCRIPT_OBJPATH} < ${BUILDVARIABLES_SRCPATH} > ${BUILDVARIABLES_OBJPATH}
+  COMMAND echo s!@LLVM_LDFLAGS@!${CMAKE_SHARED_LINKER_FLAGS}! >> temp.sed
+  COMMAND echo s!@LIBS@!${LLVM_SYSTEM_LIBS}! >> temp.sed
+  COMMAND echo s!@LLVM_BUILDMODE@!${CMAKE_BUILD_TYPE}! >> temp.sed
+  COMMAND echo s!@LLVM_OBJ_SUFFIX@!! >> temp.sed
+  COMMAND sed -f temp.sed < ${LLVM_CONFIG_IN} > ${LLVM_CONFIG}
+  COMMAND ${CMAKE_COMMAND} -E remove -f temp.sed
+  COMMAND cat ${FINAL_LIBDEPS} >> ${LLVM_CONFIG}
+  COMMAND chmod +x ${LLVM_CONFIG}
   VERBATIM
-  COMMENT "Building BuildVariables.inc include."
+  DEPENDS ${FINAL_LIBDEPS} ${LLVM_CONFIG_IN}
+  COMMENT "Building llvm-config script."
   )
 
-# Add the llvm-config tool.
-add_llvm_tool(llvm-config
-  llvm-config.cpp
-  )
+add_custom_target(llvm-config.target ALL
+  DEPENDS ${LLVM_CONFIG})
+
+# Ensure we build llvm-config after we build all of the libraries so that we
+# have their full dependencies.
+add_dependencies(llvm-config.target ${llvm_libs})
 
-# Add the dependency on the generation step.
-add_file_dependencies(${CMAKE_CURRENT_SOURCE_DIR}/llvm-config.cpp ${BUILDVARIABLES_OBJPATH})
+install(FILES ${LLVM_CONFIG}
+  PERMISSIONS OWNER_READ OWNER_WRITE OWNER_EXECUTE GROUP_READ GROUP_EXECUTE
+  WORLD_READ WORLD_EXECUTE
+  DESTINATION bin)
diff --git a/tools/llvm-config/Makefile b/tools/llvm-config/Makefile
index a7a2a63f99..184919ea97 100644
--- a/tools/llvm-config/Makefile
+++ b/tools/llvm-config/Makefile
@@ -1,5 +1,5 @@
-##===- tools/llvm-config/Makefile---------------------------*- Makefile -*-===##
-# 
+##===- tools/llvm-config/Makefile --------------------------*- Makefile -*-===##
+#
 #                     The LLVM Compiler Infrastructure
 #
 # This file is distributed under the University of Illinois Open Source
@@ -7,42 +7,57 @@
 # 
 ##===----------------------------------------------------------------------===##
 
-LEVEL := ../..
-TOOLNAME := llvm-config
-USEDLIBS := LLVMSupport.a
-
-# We generate sources in the build directory, make sure it is in the include
-# paths.
-INCLUDE_BUILD_DIR := 1
+LEVEL = ../..
 
-# This tool has no plugins, optimize startup time.
-TOOL_NO_EXPORTS := 1
-
-# Note that we have to use lazy expansion here.
-BUILDVARIABLES_SRCPATH = $(PROJ_SRC_ROOT)/tools/$(TOOLNAME)/BuildVariables.inc.in
-BUILDVARIABLES_OBJPATH = $(ObjDir)/BuildVariables.inc
-BUILT_SOURCES = $(BUILDVARIABLES_OBJPATH)
+EXTRA_DIST = LibDeps.txt FinalLibDeps.txt llvm-config.in.in find-cycles.pl
 
 include $(LEVEL)/Makefile.common
 
+# If we don't have Perl, we can't generate the library dependencies upon which 
+# llvm-config depends. Therefore, only if we detect perl will we do anything
+# useful.
+ifeq ($(HAVE_PERL),1)
+
 # Combine preprocessor flags (except for -I) and CXX flags.
-SUB_CPPFLAGS := ${CPP.BaseFlags}
-SUB_CFLAGS   := ${CPP.BaseFlags} ${C.Flags}
-SUB_CXXFLAGS := ${CPP.BaseFlags} ${CXX.Flags}
+SUB_CPPFLAGS = ${CPP.BaseFlags}
+SUB_CFLAGS   = ${CPP.BaseFlags} ${C.Flags}
+SUB_CXXFLAGS = ${CPP.BaseFlags} ${CXX.Flags}
 
 # This is blank for now.  We need to be careful about adding stuff here:
 # LDFLAGS tend not to be portable, and we don't currently require the
 # user to use libtool when linking against LLVM.
-SUB_LDFLAGS :=
+SUB_LDFLAGS = 
 
-$(ObjDir)/BuildVariables.inc: $(BUILDVARIABLES_SRCPATH) Makefile $(ObjDir)/.dir
-	$(Echo) "Building llvm-config BuildVariables.inc file."
-	$(Verb) $(ECHO) 's/@LLVM_SRC_ROOT@/$(subst /,\/,$(LLVM_SRC_ROOT))/' \
-	  > temp.sed
-	$(Verb) $(ECHO) 's/@LLVM_OBJ_ROOT@/$(subst /,\/,$(LLVM_OBJ_ROOT))/' \
-	  >> temp.sed
+FinalLibDeps = $(PROJ_OBJ_DIR)/FinalLibDeps.txt
+LibDeps      = $(PROJ_OBJ_DIR)/LibDeps.txt
+LibDepsTemp  = $(PROJ_OBJ_DIR)/LibDeps.txt.tmp
+GenLibDeps   = $(PROJ_SRC_ROOT)/utils/GenLibDeps.pl
+
+$(LibDepsTemp): $(GenLibDeps) $(LibDir) $(wildcard $(LibDir)/*.a $(LibDir)/*.o)
+	$(Echo) "Regenerating LibDeps.txt.tmp"
+	$(Verb) $(PERL) $(GenLibDeps) -flat $(LibDir) "$(NM_PATH)" > $(LibDepsTemp)
+
+$(LibDeps): $(LibDepsTemp)
+	$(Verb) $(CMP) -s $@ $< || ( $(CP) $< $@ && \
+	  $(EchoCmd) Updated LibDeps.txt because dependencies changed )
+
+# Find all the cyclic dependencies between various LLVM libraries, so we
+# don't have to process them at runtime.
+$(FinalLibDeps): find-cycles.pl $(LibDeps)
+	$(Echo) "Checking for cyclic dependencies between LLVM libraries."
+	$(Verb) $(PERL) $< < $(LibDeps) > $@ || rm -f $@
+
+# Rerun our configure substitutions as needed.
+ConfigInIn = $(PROJ_SRC_DIR)/llvm-config.in.in
+llvm-config.in: $(ConfigInIn) $(ConfigStatusScript)
+	$(Verb) cd $(PROJ_OBJ_ROOT) ; \
+		$(ConfigStatusScript) tools/llvm-config/llvm-config.in
+
+# Build our final script.
+$(ToolDir)/llvm-config: llvm-config.in $(FinalLibDeps)
+	$(Echo) "Building llvm-config script."
 	$(Verb) $(ECHO) 's/@LLVM_CPPFLAGS@/$(subst /,\/,$(SUB_CPPFLAGS))/' \
-	  >> temp.sed
+	  > temp.sed
 	$(Verb) $(ECHO) 's/@LLVM_CFLAGS@/$(subst /,\/,$(SUB_CFLAGS))/' \
 	  >> temp.sed
 	$(Verb) $(ECHO) 's/@LLVM_CXXFLAGS@/$(subst /,\/,$(SUB_CXXFLAGS))/' \
@@ -51,7 +66,28 @@ $(ObjDir)/BuildVariables.inc: $(BUILDVARIABLES_SRCPATH) Makefile $(ObjDir)/.dir
 	  >> temp.sed
 	$(Verb) $(ECHO) 's/@LLVM_BUILDMODE@/$(subst /,\/,$(BuildMode))/' \
 	  >> temp.sed
-	$(Verb) $(ECHO) 's/@LLVM_SYSTEM_LIBS@/$(subst /,\/,$(LIBS))/' \
+	$(Verb) $(ECHO) 's/@LLVM_OBJ_SUFFIX@/$(subst /,\/,/$(BuildMode))/' \
 	  >> temp.sed
 	$(Verb) $(SED) -f temp.sed < $< > $@
 	$(Verb) $(RM) temp.sed
+	$(Verb) cat $(FinalLibDeps) >> $@
+	$(Verb) chmod +x $@
+
+else
+# We don't have perl, just generate a dummy llvm-config
+$(ToolDir)/llvm-config:
+	$(Echo) "Building place holder llvm-config script."
+	$(Verb) $(ECHO) 'echo llvm-config: Perl not found so llvm-config could not be generated' >> $@
+	$(Verb) chmod +x $@
+
+endif
+# Hook into the standard Makefile rules.
+all-local:: $(ToolDir)/llvm-config
+clean-local::
+	$(Verb) $(RM) -f $(ToolDir)/llvm-config llvm-config.in $(FinalLibDeps) \
+	  $(LibDeps) GenLibDeps.out
+install-local:: all-local
+	$(Echo) Installing llvm-config
+	$(Verb) $(MKDIR) $(DESTDIR)$(PROJ_bindir)
+	$(Verb) $(ScriptInstall) $(ToolDir)/llvm-config $(DESTDIR)$(PROJ_bindir)
+
diff --git a/tools/llvm-config/find-cycles.pl b/tools/llvm-config/find-cycles.pl
new file mode 100755
index 0000000000..5cbf5b4b27
--- /dev/null
+++ b/tools/llvm-config/find-cycles.pl
@@ -0,0 +1,170 @@
+#!/usr/bin/perl
+#
+# Program:  find-cycles.pl
+#
+# Synopsis: Given a list of possibly cyclic dependencies, merge all the
+#           cycles.  This makes it possible to topologically sort the
+#           dependencies between different parts of LLVM.
+#
+# Syntax:   find-cycles.pl < LibDeps.txt > FinalLibDeps.txt
+#
+# Input:    cycmem1: cycmem2 dep1 dep2
+#           cycmem2: cycmem1 dep3 dep4
+#           boring: dep4
+#
+# Output:   cycmem1 cycmem2: dep1 dep2 dep3 dep4
+#           boring: dep4
+#
+# This file was written by Eric Kidd, and is placed into the public domain.
+#
+
+use 5.006;
+use strict;
+use warnings;
+
+my %DEPS;
+my @CYCLES;
+sub find_all_cycles;
+
+# Read our dependency information.
+while (<>) {
+    chomp;
+    my ($module, $dependency_str) = /^\s*([^:]+):\s*(.*)\s*$/;
+    die "Malformed data: $_" unless defined $dependency_str;
+    my @dependencies = split(/ /, $dependency_str);
+    $DEPS{$module} = \@dependencies;
+}
+
+# Partition our raw dependencies into sets of cyclically-connected nodes.
+find_all_cycles();
+
+# Print out the finished cycles, with their dependencies.
+my @output;
+my $cycles_found = 0;
+foreach my $cycle (@CYCLES) {
+    my @modules = sort keys %{$cycle};
+
+    # Merge the dependencies of all modules in this cycle.
+    my %dependencies;
+    foreach my $module (@modules) {
+        @dependencies{@{$DEPS{$module}}} = 1;
+    }
+
+    # Prune the known cyclic dependencies.
+    foreach my $module (@modules) {
+        delete $dependencies{$module};
+    }
+
+    # Warn about possible linker problems.
+    my @archives = grep(/\.a$/, @modules);
+    if (@archives > 1) {
+        $cycles_found = $cycles_found + 1;
+        print STDERR "find-cycles.pl: Circular dependency between *.a files:\n";
+        print STDERR "find-cycles.pl:   ", join(' ', @archives), "\n";
+        push @modules, @archives; # WORKAROUND: Duplicate *.a files. Ick.
+    } elsif (@modules > 1) {
+        $cycles_found = $cycles_found + 1;
+        print STDERR "find-cycles.pl: Circular dependency between *.o files:\n";
+        print STDERR "find-cycles.pl:   ", join(' ', @modules), "\n";
+        push @modules, @modules; # WORKAROUND: Duplicate *.o files. Ick.
+    }
+
+    # Add to our output.  (@modules is already as sorted as we need it to be.)
+    push @output, (join(' ', @modules) . ': ' .
+                   join(' ', sort keys %dependencies) . "\n");
+}
+print sort @output;
+
+exit $cycles_found;
+
+#==========================================================================
+#  Depedency Cycle Support
+#==========================================================================
+#  For now, we have cycles in our dependency graph.  Ideally, each cycle
+#  would be collapsed down to a single *.a file, saving us all this work.
+#
+#  To understand this code, you'll need a working knowledge of Perl 5,
+#  and possibly some quality time with 'man perlref'.
+
+my %SEEN;
+my %CYCLES;
+sub find_cycles ($@);
+sub found_cycles ($@);
+
+sub find_all_cycles {
+    # Find all multi-item cycles.
+    my @modules = sort keys %DEPS;
+    foreach my $module (@modules) { find_cycles($module); }
+
+    # Build fake one-item "cycles" for the remaining modules, so we can
+    # treat them uniformly.
+    foreach my $module (@modules) {
+        unless (defined $CYCLES{$module}) {
+            my %cycle = ($module, 1);
+            $CYCLES{$module} = \%cycle;
+        }
+    }
+
+    # Find all our unique cycles.  We have to do this the hard way because
+    # we apparently can't store hash references as hash keys without making
+    # 'strict refs' sad.
+    my %seen;
+    foreach my $cycle (values %CYCLES) {
+        unless ($seen{$cycle}) {
+            $seen{$cycle} = 1;
+            push @CYCLES, $cycle;
+        }
+    }
+}
+
+# Walk through our graph depth-first (keeping a trail in @path), and report
+# any cycles we find.
+sub find_cycles ($@) {
+    my ($module, @path) = @_;
+    if (str_in_list($module, @path)) {
+        found_cycle($module, @path);
+    } else {
+        return if defined $SEEN{$module};
+        $SEEN{$module} = 1;
+        foreach my $dep (@{$DEPS{$module}}) {
+            find_cycles($dep, @path, $module);
+        }
+    }
+}
+
+# Give a cycle, attempt to merge it with pre-existing cycle data.
+sub found_cycle ($@) {
+    my ($module, @path) = @_;
+
+    # Pop any modules which aren't part of our cycle.
+    while ($path[0] ne $module) { shift @path; }
+    #print join("->", @path, $module) . "\n";
+
+    # Collect the modules in our cycle into a hash.
+    my %cycle;
+    foreach my $item (@path) {
+        $cycle{$item} = 1;
+        if (defined $CYCLES{$item}) {
+            # Looks like we intersect with an existing cycle, so merge
+            # all those in, too.
+            foreach my $old_item (keys %{$CYCLES{$item}}) {
+                $cycle{$old_item} = 1;
+            }
+        }
+    }
+
+    # Update our global cycle table.
+    my $cycle_ref = \%cycle;
+    foreach my $item (keys %cycle) {
+        $CYCLES{$item} = $cycle_ref;
+    }
+    #print join(":", sort keys %cycle) . "\n";
+}
+
+sub str_in_list ($@) {
+    my ($str, @list) = @_;
+    foreach my $item (@list) {
+        return 1 if ($item eq $str);
+    }
+    return 0;
+}
diff --git a/tools/llvm-config/llvm-config.cpp b/tools/llvm-config/llvm-config.cpp
deleted file mode 100644
index 30ace56f4c..0000000000
--- a/tools/llvm-config/llvm-config.cpp
+++ /dev/null
@@ -1,324 +0,0 @@
-//===-- llvm-config.cpp - LLVM project configuration utility --------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This tool encapsulates information about an LLVM project configuration for
-// use by other project's build environments (to determine installed path,
-// available features, required libraries, etc.).
-//
-// Note that although this tool *may* be used by some parts of LLVM's build
-// itself (i.e., the Makefiles use it to compute required libraries when linking
-// tools), this tool is primarily designed to support external projects.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/ADT/StringMap.h"
-#include "llvm/ADT/StringRef.h"
-#include "llvm/ADT/Twine.h"
-#include "llvm/Config/config.h"
-#include "llvm/Config/llvm-config.h"
-#include "llvm/Support/FileSystem.h"
-#include "llvm/Support/Path.h"
-#include "llvm/Support/TargetRegistry.h"
-#include "llvm/Support/raw_ostream.h"
-#include <cstdlib>
-#include <set>
-#include <vector>
-
-using namespace llvm;
-
-// Include the build time variables we can report to the user. This is generated
-// at build time from the BuildVariables.inc.in file by the build system.
-#include "BuildVariables.inc"
-
-// Include the component table. This creates an array of struct
-// AvailableComponent entries, which record the component name, library name,
-// and required components for all of the available libraries.
-//
-// Not all components define a library, we also use "library groups" as a way to
-// create entries for pseudo groups like x86 or all-targets.
-#include "LibraryDependencies.inc"
-
-/// \brief Traverse a single component adding to the topological ordering in
-/// \arg RequiredLibs.
-///
-/// \param Name - The component to traverse.
-/// \param ComponentMap - A prebuilt map of component names to descriptors.
-/// \param VisitedComponents [in] [out] - The set of already visited components.
-/// \param RequiredLibs [out] - The ordered list of required libraries.
-static void VisitComponent(StringRef Name,
-                           const StringMap<AvailableComponent*> &ComponentMap,
-                           std::set<AvailableComponent*> &VisitedComponents,
-                           std::vector<StringRef> &RequiredLibs) {
-  // Lookup the component.
-  AvailableComponent *AC = ComponentMap.lookup(Name);
-  assert(AC && "Invalid component name!");
-
-  // Add to the visited table.
-  if (!VisitedComponents.insert(AC).second) {
-    // We are done if the component has already been visited.
-    return;
-  }
-
-  // Otherwise, visit all the dependencies.
-  for (unsigned i = 0; AC->RequiredLibraries[i]; ++i) {
-    VisitComponent(AC->RequiredLibraries[i], ComponentMap, VisitedComponents,
-                   RequiredLibs);
-  }
-
-  // Add to the required library list.
-  if (AC->Library)
-    RequiredLibs.push_back(AC->Library);
-}
-
-/// \brief Compute the list of required libraries for a given list of
-/// components, in an order suitable for passing to a linker (that is, libraries
-/// appear prior to their dependencies).
-///
-/// \param Components - The names of the components to find libraries for.
-/// \param RequiredLibs [out] - On return, the ordered list of libraries that
-/// are required to link the given components.
-void ComputeLibsForComponents(const std::vector<StringRef> &Components,
-                              std::vector<StringRef> &RequiredLibs) {
-  std::set<AvailableComponent*> VisitedComponents;
-
-  // Build a map of component names to information.
-  StringMap<AvailableComponent*> ComponentMap;
-  for (unsigned i = 0; i != array_lengthof(AvailableComponents); ++i) {
-    AvailableComponent *AC = &AvailableComponents[i];
-    ComponentMap[AC->Name] = AC;
-  }
-
-  // Visit the components.
-  for (unsigned i = 0, e = Components.size(); i != e; ++i) {
-    // Users are allowed to provide mixed case component names.
-    std::string ComponentLower = Components[i].lower();
-
-    // Validate that the user supplied a valid component name.
-    if (!ComponentMap.count(ComponentLower)) {
-      llvm::errs() << "llvm-config: unknown component name: " << Components[i]
-                   << "\n";
-      exit(1);
-    }
-
-    VisitComponent(ComponentLower, ComponentMap, VisitedComponents,
-                   RequiredLibs);
-  }
-
-  // The list is now ordered with leafs first, we want the libraries to printed
-  // in the reverse order of dependency.
-  std::reverse(RequiredLibs.begin(), RequiredLibs.end());
-}
-
-/* *** */
-
-void usage() {
-  errs() << "\
-usage: llvm-config <OPTION>... [<COMPONENT>...]\n\
-\n\
-Get various configuration information needed to compile programs which use\n\
-LLVM.  Typically called from 'configure' scripts.  Examples:\n\
-  llvm-config --cxxflags\n\
-  llvm-config --ldflags\n\
-  llvm-config --libs engine bcreader scalaropts\n\
-\n\
-Options:\n\
-  --version         Print LLVM version.\n\
-  --prefix          Print the installation prefix.\n\
-  --src-root        Print the source root LLVM was built from.\n\
-  --obj-root        Print the object root used to build LLVM.\n\
-  --bindir          Directory containing LLVM executables.\n\
-  --includedir      Directory containing LLVM headers.\n\
-  --libdir          Directory containing LLVM libraries.\n\
-  --cppflags        C preprocessor flags for files that include LLVM headers.\n\
-  --cflags          C compiler flags for files that include LLVM headers.\n\
-  --cxxflags        C++ compiler flags for files that include LLVM headers.\n\
-  --ldflags         Print Linker flags.\n\
-  --libs            Libraries needed to link against LLVM components.\n\
-  --libnames        Bare library names for in-tree builds.\n\
-  --libfiles        Fully qualified library filenames for makefile depends.\n\
-  --components      List of all possible components.\n\
-  --targets-built   List of all targets currently built.\n\
-  --host-target     Target triple used to configure LLVM.\n\
-  --build-mode      Print build mode of LLVM tree (e.g. Debug or Release).\n\
-Typical components:\n\
-  all               All LLVM libraries (default).\n\
-  backend           Either a native backend or the C backend.\n\
-  engine            Either a native JIT or a bitcode interpreter.\n";
-  exit(1);
-}
-
-/// \brief Compute the path to the main executable.
-llvm::sys::Path GetExecutablePath(const char *Argv0) {
-  // This just needs to be some symbol in the binary; C++ doesn't
-  // allow taking the address of ::main however.
-  void *P = (void*) (intptr_t) GetExecutablePath;
-  return llvm::sys::Path::GetMainExecutable(Argv0, P);
-}
-
-int main(int argc, char **argv) {
-  std::vector<StringRef> Components;
-  bool PrintLibs = false, PrintLibNames = false, PrintLibFiles = false;
-  bool HasAnyOption = false;
-
-  // llvm-config is designed to support being run both from a development tree
-  // and from an installed path. We try and auto-detect which case we are in so
-  // that we can report the correct information when run from a development
-  // tree.
-  bool IsInDevelopmentTree, DevelopmentTreeLayoutIsCMakeStyle;
-  llvm::SmallString<256> CurrentPath(GetExecutablePath(argv[0]).str());
-  std::string CurrentExecPrefix;
-
-  // Create an absolute path, and pop up one directory (we expect to be inside a
-  // bin dir).
-  sys::fs::make_absolute(CurrentPath);
-  CurrentExecPrefix = sys::path::parent_path(
-    sys::path::parent_path(CurrentPath)).str();
-
-  // Check to see if we are inside a development tree by comparing to possible
-  // locations (prefix style or CMake style). This could be wrong in the face of
-  // symbolic links, but is good enough.
-  if (CurrentExecPrefix == std::string(LLVM_OBJ_ROOT) + "/" + LLVM_BUILDMODE) {
-    IsInDevelopmentTree = true;
-    DevelopmentTreeLayoutIsCMakeStyle = false;
-  } else if (CurrentExecPrefix == std::string(LLVM_OBJ_ROOT) + "/bin") {
-    IsInDevelopmentTree = true;
-    DevelopmentTreeLayoutIsCMakeStyle = true;
-  } else {
-    IsInDevelopmentTree = false;
-  }
-
-  // Compute various directory locations based on the derived location
-  // information.
-  std::string ActivePrefix, ActiveBinDir, ActiveIncludeDir, ActiveLibDir;
-  std::string ActiveIncludeOption;
-  if (IsInDevelopmentTree) {
-    ActivePrefix = CurrentExecPrefix;
-
-    // CMake organizes the products differently than a normal prefix style
-    // layout.
-    if (DevelopmentTreeLayoutIsCMakeStyle) {
-      ActiveIncludeDir = std::string(LLVM_OBJ_ROOT) + "/include";
-      ActiveBinDir = std::string(LLVM_OBJ_ROOT) + "/bin/" + LLVM_BUILDMODE;
-      ActiveLibDir = std::string(LLVM_OBJ_ROOT) + "/lib/" + LLVM_BUILDMODE;
-    } else {
-        ActiveIncludeDir = std::string(LLVM_OBJ_ROOT) + "/include";
-      ActiveBinDir = std::string(LLVM_OBJ_ROOT) + "/" + LLVM_BUILDMODE + "/bin";
-      ActiveLibDir = std::string(LLVM_OBJ_ROOT) + "/" + LLVM_BUILDMODE + "/lib";
-    }
-
-    // We need to include files from both the source and object trees.
-    ActiveIncludeOption = ("-I" + ActiveIncludeDir + " " +
-                           "-I" + LLVM_OBJ_ROOT + "/include");
-  } else {
-    ActivePrefix = CurrentExecPrefix;
-    ActiveIncludeDir = ActivePrefix + "/include";
-    ActiveBinDir = ActivePrefix + "/bin";
-    ActiveLibDir = ActivePrefix + "/lib";
-    ActiveIncludeOption = "-I" + ActiveIncludeDir;
-  }
-
-  raw_ostream &OS = outs();
-  for (int i = 1; i != argc; ++i) {
-    StringRef Arg = argv[i];
-
-    if (Arg.startswith("-")) {
-      HasAnyOption = true;
-      if (Arg == "--version") {
-        OS << PACKAGE_VERSION << '\n';
-      } else if (Arg == "--prefix") {
-        OS << ActivePrefix << '\n';
-      } else if (Arg == "--bindir") {
-        OS << ActiveBinDir << '\n';
-      } else if (Arg == "--includedir") {
-        OS << ActiveIncludeDir << '\n';
-      } else if (Arg == "--libdir") {
-        OS << ActiveLibDir << '\n';
-      } else if (Arg == "--cppflags") {
-        OS << ActiveIncludeOption << ' ' << LLVM_CPPFLAGS << '\n';
-      } else if (Arg == "--cflags") {
-        OS << ActiveIncludeOption << ' ' << LLVM_CFLAGS << '\n';
-      } else if (Arg == "--cxxflags") {
-        OS << ActiveIncludeOption << ' ' << LLVM_CXXFLAGS << '\n';
-      } else if (Arg == "--ldflags") {
-        OS << "-L" << ActiveLibDir << ' ' << LLVM_LDFLAGS
-           << ' ' << LLVM_SYSTEM_LIBS << '\n';
-      } else if (Arg == "--libs") {
-        PrintLibs = true;
-      } else if (Arg == "--libnames") {
-        PrintLibNames = true;
-      } else if (Arg == "--libfiles") {
-        PrintLibFiles = true;
-      } else if (Arg == "--components") {
-        for (unsigned j = 0; j != array_lengthof(AvailableComponents); ++j) {
-          OS << ' ';
-          OS << AvailableComponents[j].Name;
-        }
-        OS << '\n';
-      } else if (Arg == "--targets-built") {
-        bool First = true;
-        for (TargetRegistry::iterator I = TargetRegistry::begin(),
-               E = TargetRegistry::end(); I != E; First = false, ++I) {
-          if (!First)
-            OS << ' ';
-          OS << I->getName();
-        }
-        OS << '\n';
-      } else if (Arg == "--host-target") {
-        OS << LLVM_DEFAULT_TARGET_TRIPLE << '\n';
-      } else if (Arg == "--build-mode") {
-        OS << LLVM_BUILDMODE << '\n';
-      } else if (Arg == "--obj-root") {
-        OS << LLVM_OBJ_ROOT << '\n';
-      } else if (Arg == "--src-root") {
-        OS << LLVM_SRC_ROOT << '\n';
-      } else {
-        usage();
-      }
-    } else {
-      Components.push_back(Arg);
-    }
-  }
-
-  if (!HasAnyOption)
-    usage();
-
-  if (PrintLibs || PrintLibNames || PrintLibFiles) {
-    // Construct the list of all the required libraries.
-    std::vector<StringRef> RequiredLibs;
-    ComputeLibsForComponents(Components, RequiredLibs);
-
-    for (unsigned i = 0, e = RequiredLibs.size(); i != e; ++i) {
-      StringRef Lib = RequiredLibs[i];
-      if (i)
-        OS << ' ';
-
-      if (PrintLibNames) {
-        OS << Lib;
-      } else if (PrintLibFiles) {
-        OS << ActiveLibDir << '/' << Lib;
-      } else if (PrintLibs) {
-        // If this is a typical library name, include it using -l.
-        if (Lib.startswith("lib") && Lib.endswith(".a")) {
-          OS << "-l" << Lib.slice(3, Lib.size()-2);
-          continue;
-        }
-
-        // Otherwise, print the full path.
-        OS << ActiveLibDir << '/' << Lib;
-      }
-    }
-    OS << '\n';
-  } else if (!Components.empty()) {
-    errs() << "llvm-config: error: components given, but unused\n\n";
-    usage();
-  }
-
-  return 0;
-}
diff --git a/tools/llvm-config/llvm-config.in.in b/tools/llvm-config/llvm-config.in.in
new file mode 100644
index 0000000000..d811e59abb
--- /dev/null
+++ b/tools/llvm-config/llvm-config.in.in
@@ -0,0 +1,466 @@
+#!@PERL@
+##===- tools/llvm-config ---------------------------------------*- perl -*-===##
+# 
+#                     The LLVM Compiler Infrastructure
+#
+# This file 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;
+use Cwd 'abs_path';
+
+#---- 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 $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 $CPPFLAGS            = q{@LLVM_CPPFLAGS@};
+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@};
+my $LLVM_OBJ_SUFFIX     = q{@LLVM_OBJ_SUFFIX@};
+#---- end Makefile values ----
+
+# Figure out where llvm-config is being run from.  Primarily, we care if it has
+# been installed, or is running from the build directory, which changes the
+# locations of some files.
+
+# Convert the current executable name into its directory (e.g. ".").
+my ($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 $ABS_RUN_DIR = abs_path("$RUN_DIR/..");
+chomp($ABS_RUN_DIR);
+
+# Compute the absolute object directory build, e.g. "foo/llvm/Debug".
+my $ABS_OBJ_ROOT = "$LLVM_OBJ_ROOT$LLVM_OBJ_SUFFIX";
+$ABS_OBJ_ROOT = abs_path("$ABS_OBJ_ROOT") if (-d $ABS_OBJ_ROOT);
+chomp($ABS_OBJ_ROOT);
+
+my $INCLUDEDIR = "$ABS_RUN_DIR/include";
+my $INCLUDEOPTION = "-I$INCLUDEDIR";
+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";
+  # We need include files from both the srcdir and objdir.
+  $INCLUDEOPTION = "-I$INCLUDEDIR -I$LLVM_OBJ_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 "--cppflags") {
+            $has_opt = 1; print "$INCLUDEOPTION $CPPFLAGS\n";
+        } elsif ($arg eq "--cflags") {
+            $has_opt = 1; print "$INCLUDEOPTION $CFLAGS\n";
+        } elsif ($arg eq "--cxxflags") {
+            $has_opt = 1; print "$INCLUDEOPTION $CXXFLAGS\n";
+        } elsif ($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") {
+            $has_opt = 1; print abs_path("$LLVM_OBJ_ROOT/");
+        } elsif ($arg eq "--src-root") {
+            $has_opt = 1; print abs_path("$LLVM_SRC_ROOT/");
+        } 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.
+  --cppflags         C preprocessor flags for files that include LLVM headers.
+  --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).
+  engine             Either a native JIT or a bitcode 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 target-specific entries
+    my @all_targets;
+    foreach my $target (@TARGETS_BUILT) {
+        # FIXME: Temporary, until we don't switch all targets
+        if (defined $NAME_MAP{$target.'asmprinter'}) {
+            $NAME_MAP{$target} = [$target.'info',
+                                  $target.'asmprinter', 
+                                  $target.'codegen']
+        } elsif (defined $NAME_MAP{$target.'codegen'}) {
+            $NAME_MAP{$target} = [$target.'info',
+                                  $target.'codegen']
+        } else {
+            $NAME_MAP{$target} = [$target.'info',
+                                  $NAME_MAP{$target}[0]]
+        }
+
+        if (defined $NAME_MAP{$target.'asmparser'}) {
+            push @{$NAME_MAP{$target}},$target.'asmparser'
+        }
+
+        if (defined $NAME_MAP{$target.'disassembler'}) {
+            push @{$NAME_MAP{$target}},$target.'disassembler'
+        }
+
+        push @all_targets, $target;
+    }
+
+    # Add virtual entries.
+    $NAME_MAP{'native'}  = have_native_backend() ? [$ARCH] : [];
+    $NAME_MAP{'nativecodegen'} = have_native_backend() ? [$ARCH.'codegen'] : [];
+    $NAME_MAP{'engine'}  = find_best_engine;
+    $NAME_MAP{'all-targets'}     = \@all_targets;
+    $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__
-- 
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