Resubmit "[lit] Force site configs to run before source-tree configs"

This is a resubmission of r313270.  It broke standalone builds of
compiler-rt because we were not correctly generating the llvm-lit
script in the standalone build directory.

The fixes incorporated here attempt to find llvm/utils/llvm-lit
from the source tree returned by llvm-config.  If present, it
will generate llvm-lit into the output directory.  Regardless,
the user can specify -DLLVM_EXTERNAL_LIT to point to a specific
lit.py on their file system.  This supports the use case of
someone installing lit via a package manager.  If it cannot find
a source tree, and -DLLVM_EXTERNAL_LIT is either unspecified or
invalid, then we print a warning that tests will not be able
to run.

Differential Revision: https://reviews.llvm.org/D37756

llvm-svn: 313407

24 files changed, 254 insertions, 801 deletions

diff --git a/clang-tools-extra/test/Unit/lit.cfg b/clang-tools-extra/test/Unit/lit.cfg
index 3a1da187eb4..fc63afdbe86 100644
--- a/clang-tools-extra/test/Unit/lit.cfg
+++ b/clang-tools-extra/test/Unit/lit.cfg
@@ -9,10 +9,9 @@ config.suffixes = [] # Seems not to matter for google tests?
 
 # Test Source and Exec root dirs both point to the same directory where google
 # test binaries are built.
-extra_tools_obj_dir = getattr(config, 'extra_tools_obj_dir', None)
-if extra_tools_obj_dir is not None:
-  config.test_source_root = extra_tools_obj_dir
-  config.test_exec_root = config.test_source_root
+
+config.test_source_root = config.extra_tools_obj_dir
+config.test_exec_root = config.test_source_root
 
 # All GoogleTests are named to have 'Tests' as their suffix. The '.' option is
 # a special value for GoogleTest indicating that it should look through the
@@ -20,18 +19,6 @@ if extra_tools_obj_dir is not None:
 # ;-separated list of subdirectories).
 config.test_format = lit.formats.GoogleTest('.', 'Tests')
 
-# If the site-specific configuration wasn't loaded (e.g. the build system failed
-# to create it or the user is running a test file directly) try to come up with
-# sane config options.
-if config.test_exec_root is None:
-  # Look for a --param=extra_tools_unit_site_config option.
-  site_cfg = lit_config.params.get('extra_tools_unit_site_config', None)
-  if site_cfg and os.path.exists(site_cfg):
-      lit_config.load_config(config, site_cfg)
-      raise SystemExit
-
-  # FIXME: Support out-of-tree builds? See clang/test/Unit/lit.cfg if we care.
-
 shlibpath_var = ''
 if platform.system() == 'Linux':
     shlibpath_var = 'LD_LIBRARY_PATH'
@@ -41,17 +28,11 @@ elif platform.system() == 'Windows':
     shlibpath_var = 'PATH'
 
 # Point the dynamic loader at dynamic libraries in 'lib'.
-shlibdir = getattr(config, 'shlibdir', None)
-if not shlibdir:
-    lit_config.fatal('No shlibdir set!')
-llvm_libs_dir = getattr(config, 'llvm_libs_dir', None)
-if not llvm_libs_dir:
-    lit_config.fatal('No LLVM libs dir set!')
-shlibpath = os.path.pathsep.join((shlibdir, llvm_libs_dir,
+shlibpath = os.path.pathsep.join((config.shlibdir, config.llvm_libs_dir,
                                  config.environment.get(shlibpath_var,'')))
 
 # Win32 seeks DLLs along %PATH%.
-if sys.platform in ['win32', 'cygwin'] and os.path.isdir(shlibdir):
-    shlibpath = os.path.pathsep.join((shlibdir, shlibpath))
+if sys.platform in ['win32', 'cygwin'] and os.path.isdir(config.shlibdir):
+    shlibpath = os.path.pathsep.join((config.shlibdir, shlibpath))
 
 config.environment[shlibpath_var] = shlibpath
diff --git a/clang-tools-extra/test/lit.cfg b/clang-tools-extra/test/lit.cfg
index 25f29189bc9..3bffbdbdf4d 100644
--- a/clang-tools-extra/test/lit.cfg
+++ b/clang-tools-extra/test/lit.cfg
@@ -54,9 +54,7 @@ config.excludes = ['Inputs']
 config.test_source_root = os.path.dirname(__file__)
 
 # test_exec_root: The root path where tests should be run.
-clang_tools_binary_dir = getattr(config, 'clang_tools_binary_dir', None)
-if clang_tools_binary_dir is not None:
-    config.test_exec_root = os.path.join(clang_tools_binary_dir, 'test')
+config.test_exec_root = os.path.join(config.clang_tools_binary_dir, 'test')
 
 # Clear some environment variables that might affect Clang.
 #
@@ -88,92 +86,19 @@ for name in possibly_dangerous_env_vars:
     del config.environment[name]
 
 # Tweak the PATH to include the tools dir and the scripts dir.
-if clang_tools_binary_dir is not None:
-    clang_tools_dir = getattr(config, 'clang_tools_dir', None)
-    if not clang_tools_dir:
-        lit_config.fatal('No Clang tools dir set!')
-    llvm_tools_dir = getattr(config, 'llvm_tools_dir', None)
-    if not llvm_tools_dir:
-        lit_config.fatal('No LLVM tools dir set!')
-    path = os.path.pathsep.join((
-            clang_tools_dir, llvm_tools_dir, config.environment['PATH']))
-    config.environment['PATH'] = path
-
-    clang_libs_dir = getattr(config, 'clang_libs_dir', None)
-    if not clang_libs_dir:
-        lit_config.fatal('No Clang libs dir set!')
-    llvm_libs_dir = getattr(config, 'llvm_libs_dir', None)
-    if not llvm_libs_dir:
-        lit_config.fatal('No LLVM libs dir set!')
-    path = os.path.pathsep.join((clang_libs_dir, llvm_libs_dir,
-                                 config.environment.get('LD_LIBRARY_PATH','')))
-    config.environment['LD_LIBRARY_PATH'] = path
-
-###
-
-# Check that the object root is known.
-if config.test_exec_root is None:
-    # Otherwise, we haven't loaded the site specific configuration (the user is
-    # probably trying to run on a test file directly, and either the site
-    # configuration hasn't been created by the build system, or we are in an
-    # out-of-tree build situation).
-
-    # Check for 'clang_site_config' user parameter, and use that if available.
-    site_cfg = lit_config.params.get('clang_tools_extra_site_config', None)
-    if site_cfg and os.path.exists(site_cfg):
-        lit_config.load_config(config, site_cfg)
-        raise SystemExit
-
-    # Try to detect the situation where we are using an out-of-tree build by
-    # looking for 'llvm-config'.
-    #
-    # FIXME: I debated (i.e., wrote and threw away) adding logic to
-    # automagically generate the lit.site.cfg if we are in some kind of fresh
-    # build situation. This means knowing how to invoke the build system though,
-    # and I decided it was too much magic. We should solve this by just having
-    # the .cfg files generated during the configuration step.
-
-    llvm_config = lit.util.which('llvm-config', config.environment['PATH'])
-    if not llvm_config:
-        lit_config.fatal('No site specific configuration available!')
-
-    # Get the source and object roots.
-    llvm_src_root = lit.util.capture(['llvm-config', '--src-root']).strip()
-    llvm_obj_root = lit.util.capture(['llvm-config', '--obj-root']).strip()
-    clang_src_root = os.path.join(llvm_src_root, "tools", "clang")
-    clang_obj_root = os.path.join(llvm_obj_root, "tools", "clang")
-
-    clang_tools_extra_src_root = os.path.join(clang_src_root, "tools", "extra")
-    clang_tools_extra_obj_root = os.path.join(clang_obj_root, "tools", "extra")
-    # Validate that we got a tree which points to here, using the standard
-    # tools/clang layout.
-    this_src_root = os.path.dirname(config.test_source_root)
-    if os.path.realpath(clang_tools_extra_src_root) != os.path.realpath(this_src_root):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Check that the site specific configuration exists.
-    site_cfg = os.path.join(clang_tools_extra_obj_root, 'test', 'lit.site.cfg')
-    if not os.path.exists(site_cfg):
-        lit_config.fatal(
-            'No site specific configuration available! You may need to '
-            'run "make test" in your Clang build directory.')
-
-    # Okay, that worked. Notify the user of the automagic, and reconfigure.
-    lit_config.note('using out-of-tree build at %r' % clang_obj_root)
-    lit_config.load_config(config, site_cfg)
-    raise SystemExit
-
-###
+path = os.path.pathsep.join((
+        config.clang_tools_dir, config.llvm_tools_dir, config.environment['PATH']))
+config.environment['PATH'] = path
 
-import os
+path = os.path.pathsep.join((config.clang_libs_dir, config.llvm_libs_dir,
+                              config.environment.get('LD_LIBRARY_PATH','')))
+config.environment['LD_LIBRARY_PATH'] = path
 
 # When running under valgrind, we mangle '-vg' onto the end of the triple so we
 # can check it with XFAIL and XTARGET.
 if lit_config.useValgrind:
     config.target_triple += '-vg'
 
-###
-
 # Set available features we allow tests to conditionalize on.
 #
 # As of 2011.08, crash-recovery tests still do not pass on FreeBSD.
diff --git a/clang/runtime/CMakeLists.txt b/clang/runtime/CMakeLists.txt
index 470f190209b..f89cd4903fb 100644
--- a/clang/runtime/CMakeLists.txt
+++ b/clang/runtime/CMakeLists.txt
@@ -77,6 +77,7 @@ if(LLVM_BUILD_EXTERNAL_COMPILER_RT AND EXISTS ${COMPILER_RT_SRC_ROOT}/)
                -DCOMPILER_RT_INCLUDE_TESTS=${LLVM_INCLUDE_TESTS}
                -DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}
                -DLLVM_LIBDIR_SUFFIX=${LLVM_LIBDIR_SUFFIX}
+               -DLLVM_RUNTIME_OUTPUT_INTDIR=${LLVM_RUNTIME_OUTPUT_INTDIR}
                -DCMAKE_OSX_DEPLOYMENT_TARGET=${CMAKE_OSX_DEPLOYMENT_TARGET}
                -DCMAKE_OSX_SYSROOT:PATH=${CMAKE_OSX_SYSROOT}
                ${COMPILER_RT_PASSTHROUGH_VARIABLES}
diff --git a/clang/test/Unit/lit.cfg b/clang/test/Unit/lit.cfg
index 90eb2ac604a..c4794ccbe58 100644
--- a/clang/test/Unit/lit.cfg
+++ b/clang/test/Unit/lit.cfg
@@ -17,14 +17,11 @@ config.suffixes = []
 
 # test_source_root: The root path where tests are located.
 # test_exec_root: The root path where tests should be run.
-clang_obj_root = getattr(config, 'clang_obj_root', None)
-if clang_obj_root is not None:
-    config.test_exec_root = os.path.join(clang_obj_root, 'unittests')
-    config.test_source_root = config.test_exec_root
+config.test_exec_root = os.path.join(config.clang_obj_root, 'unittests')
+config.test_source_root = config.test_exec_root
 
 # testFormat: The test format to use to interpret tests.
-llvm_build_mode = getattr(config, 'llvm_build_mode', "Debug")
-config.test_format = lit.formats.GoogleTest(llvm_build_mode, 'Tests')
+config.test_format = lit.formats.GoogleTest(config.llvm_build_mode, 'Tests')
 
 # Propagate the temp directory. Windows requires this because it uses \Windows\
 # if none of these are present.
@@ -38,55 +35,6 @@ for symbolizer in ['ASAN_SYMBOLIZER_PATH', 'MSAN_SYMBOLIZER_PATH']:
     if symbolizer in os.environ:
         config.environment[symbolizer] = os.environ[symbolizer]
 
-###
-
-# Check that the object root is known.
-if config.test_exec_root is None:
-    # Otherwise, we haven't loaded the site specific configuration (the user is
-    # probably trying to run on a test file directly, and either the site
-    # configuration hasn't been created by the build system, or we are in an
-    # out-of-tree build situation).
-
-    # Check for 'clang_unit_site_config' user parameter, and use that if available.
-    site_cfg = lit_config.params.get('clang_unit_site_config', None)
-    if site_cfg and os.path.exists(site_cfg):
-        lit_config.load_config(config, site_cfg)
-        raise SystemExit
-
-    # Try to detect the situation where we are using an out-of-tree build by
-    # looking for 'llvm-config'.
-    #
-    # FIXME: I debated (i.e., wrote and threw away) adding logic to
-    # automagically generate the lit.site.cfg if we are in some kind of fresh
-    # build situation. This means knowing how to invoke the build system
-    # though, and I decided it was too much magic.
-
-    llvm_config = lit.util.which('llvm-config', config.environment['PATH'])
-    if not llvm_config:
-        lit_config.fatal('No site specific configuration available!')
-
-    # Get the source and object roots.
-    llvm_src_root = subprocess.check_output(['llvm-config', '--src-root']).strip()
-    llvm_obj_root = subprocess.check_output(['llvm-config', '--obj-root']).strip()
-    clang_src_root = os.path.join(llvm_src_root, "tools", "clang")
-    clang_obj_root = os.path.join(llvm_obj_root, "tools", "clang")
-
-    # Validate that we got a tree which points to here, using the standard
-    # tools/clang layout.
-    this_src_root = os.path.join(os.path.dirname(__file__),'..','..')
-    if os.path.realpath(clang_src_root) != os.path.realpath(this_src_root):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Check that the site specific configuration exists.
-    site_cfg = os.path.join(clang_obj_root, 'test', 'Unit', 'lit.site.cfg')
-    if not os.path.exists(site_cfg):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Okay, that worked. Notify the user of the automagic, and reconfigure.
-    lit_config.note('using out-of-tree build at %r' % clang_obj_root)
-    lit_config.load_config(config, site_cfg)
-    raise SystemExit
-
 shlibpath_var = ''
 if platform.system() == 'Linux':
     shlibpath_var = 'LD_LIBRARY_PATH'
@@ -97,14 +45,7 @@ elif platform.system() == 'Windows':
 
 # in stand-alone builds, shlibdir is clang's build tree
 # while llvm_libs_dir is installed LLVM (and possibly older clang)
-llvm_shlib_dir = getattr(config, 'shlibdir', None)
-if not llvm_shlib_dir:
-    lit_config.fatal('No shlibdir set!')
-# Point the dynamic loader at dynamic libraries in 'lib'.
-llvm_libs_dir = getattr(config, 'llvm_libs_dir', None)
-if not llvm_libs_dir:
-    lit_config.fatal('No LLVM libs dir set!')
-shlibpath = os.path.pathsep.join((llvm_shlib_dir, llvm_libs_dir,
+shlibpath = os.path.pathsep.join((config.shlibdir, config.llvm_libs_dir,
                                  config.environment.get(shlibpath_var,'')))
 
 config.environment[shlibpath_var] = shlibpath
diff --git a/clang/test/lit.cfg b/clang/test/lit.cfg
index 6b7159ced8d..d258286274e 100644
--- a/clang/test/lit.cfg
+++ b/clang/test/lit.cfg
@@ -55,13 +55,7 @@ config.excludes = ['Inputs', 'CMakeLists.txt', 'README.txt', 'LICENSE.txt']
 config.test_source_root = os.path.dirname(__file__)
 
 # test_exec_root: The root path where tests should be run.
-clang_obj_root = getattr(config, 'clang_obj_root', None)
-if clang_obj_root is not None:
-    config.test_exec_root = os.path.join(clang_obj_root, 'test')
-
-# Set llvm_{src,obj}_root for use by others.
-config.llvm_src_root = getattr(config, 'llvm_src_root', None)
-config.llvm_obj_root = getattr(config, 'llvm_obj_root', None)
+config.test_exec_root = os.path.join(config.clang_obj_root, 'test')
 
 # Clear some environment variables that might affect Clang.
 #
@@ -92,91 +86,20 @@ for name in possibly_dangerous_env_vars:
     del config.environment[name]
 
 # Tweak the PATH to include the tools dir and the scripts dir.
-if clang_obj_root is not None:
-    clang_tools_dir = getattr(config, 'clang_tools_dir', None)
-    if not clang_tools_dir:
-        lit_config.fatal('No Clang tools dir set!')
-    llvm_tools_dir = getattr(config, 'llvm_tools_dir', None)
-    if not llvm_tools_dir:
-        lit_config.fatal('No LLVM tools dir set!')
-    path = os.path.pathsep.join((
-            clang_tools_dir, llvm_tools_dir, config.environment['PATH']))
-    config.environment['PATH'] = path
-    # in stand-alone builds, llvm_shlib_dir is clang's build tree
-    # while llvm_libs_dir is installed LLVM (and possibly older clang)
-    llvm_shlib_dir = getattr(config, 'llvm_shlib_dir', None)
-    if not llvm_shlib_dir:
-        lit_config.fatal('No LLVM shlib dir set!')
-    llvm_libs_dir = getattr(config, 'llvm_libs_dir', None)
-    if not llvm_libs_dir:
-        lit_config.fatal('No LLVM libs dir set!')
-    path = os.path.pathsep.join((llvm_shlib_dir, llvm_libs_dir,
-                                 config.environment.get('LD_LIBRARY_PATH','')))
-    config.environment['LD_LIBRARY_PATH'] = path
+path = os.path.pathsep.join((
+        config.clang_tools_dir, config.llvm_tools_dir, config.environment['PATH']))
+config.environment['PATH'] = path
+path = os.path.pathsep.join((config.llvm_shlib_dir, config.llvm_libs_dir,
+                              config.environment.get('LD_LIBRARY_PATH','')))
+config.environment['LD_LIBRARY_PATH'] = path
 
 # Propagate path to symbolizer for ASan/MSan.
 for symbolizer in ['ASAN_SYMBOLIZER_PATH', 'MSAN_SYMBOLIZER_PATH']:
     if symbolizer in os.environ:
         config.environment[symbolizer] = os.environ[symbolizer]
 
-###
-
-# Check that the object root is known.
-if config.test_exec_root is None:
-    # Otherwise, we haven't loaded the site specific configuration (the user is
-    # probably trying to run on a test file directly, and either the site
-    # configuration hasn't been created by the build system, or we are in an
-    # out-of-tree build situation).
-
-    # Check for 'clang_site_config' user parameter, and use that if available.
-    site_cfg = lit_config.params.get('clang_site_config', None)
-    if site_cfg and os.path.exists(site_cfg):
-        lit_config.load_config(config, site_cfg)
-        raise SystemExit
-
-    # Try to detect the situation where we are using an out-of-tree build by
-    # looking for 'llvm-config'.
-    #
-    # FIXME: I debated (i.e., wrote and threw away) adding logic to
-    # automagically generate the lit.site.cfg if we are in some kind of fresh
-    # build situation. This means knowing how to invoke the build system though,
-    # and I decided it was too much magic. We should solve this by just having
-    # the .cfg files generated during the configuration step.
-
-    llvm_config = lit.util.which('llvm-config', config.environment['PATH'])
-    if not llvm_config:
-        lit_config.fatal('No site specific configuration available!')
-
-    # Get the source and object roots.
-    llvm_src_root = subprocess.check_output(['llvm-config', '--src-root']).strip()
-    llvm_obj_root = subprocess.check_output(['llvm-config', '--obj-root']).strip()
-    clang_src_root = os.path.join(llvm_src_root, "tools", "clang")
-    clang_obj_root = os.path.join(llvm_obj_root, "tools", "clang")
-
-    # Validate that we got a tree which points to here, using the standard
-    # tools/clang layout.
-    this_src_root = os.path.dirname(config.test_source_root)
-    if os.path.realpath(clang_src_root) != os.path.realpath(this_src_root):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Check that the site specific configuration exists.
-    site_cfg = os.path.join(clang_obj_root, 'test', 'lit.site.cfg')
-    if not os.path.exists(site_cfg):
-        lit_config.fatal(
-            'No site specific configuration available! You may need to '
-            'run "make test" in your Clang build directory.')
-
-    # Okay, that worked. Notify the user of the automagic, and reconfigure.
-    lit_config.note('using out-of-tree build at %r' % clang_obj_root)
-    lit_config.load_config(config, site_cfg)
-    raise SystemExit
-
-###
-
 # Discover the 'clang' and 'clangcc' to use.
 
-import os
-
 def inferClang(PATH):
     # Determine which clang to use.
     clang = os.getenv('CLANG')
@@ -315,7 +238,7 @@ config.substitutions.append(
 # with the full path to the build directory holding that tool.  This
 # ensures that we are testing the tools just built and not some random
 # tools that might happen to be in the user's PATH.
-tool_dirs = os.path.pathsep.join((clang_tools_dir, llvm_tools_dir))
+tool_dirs = os.path.pathsep.join((config.clang_tools_dir, config.llvm_tools_dir))
 
 # Regex assertions to reject neighbor hyphens/dots (seen in some tests).
 # For example, don't match 'clang-check-' or '.clang-format'.
@@ -351,7 +274,7 @@ for pattern in tool_patterns:
     if not tool_path:
         # Warn, but still provide a substitution.
         lit_config.note('Did not find ' + tool_name + ' in ' + tool_dirs)
-        tool_path = clang_tools_dir + '/' + tool_name
+        tool_path = config.clang_tools_dir + '/' + tool_name
     config.substitutions.append((pattern, tool_pipe + tool_path))
 
 ###
@@ -451,7 +374,7 @@ def get_llvm_config_props():
 
     cmd = subprocess.Popen(
         [
-            os.path.join(llvm_tools_dir, 'llvm-config'),
+            os.path.join(config.llvm_tools_dir, 'llvm-config'),
             '--assertion-mode',
             '--targets-built',
             '--cxxflags'
diff --git a/compiler-rt/CMakeLists.txt b/compiler-rt/CMakeLists.txt
index 90cdac73a33..e021bf84af0 100644
--- a/compiler-rt/CMakeLists.txt
+++ b/compiler-rt/CMakeLists.txt
@@ -62,6 +62,7 @@ if (COMPILER_RT_STANDALONE_BUILD)
     set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT} --no-progress-bar")
   endif()
   set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING "Default options for lit")
+  set(LLVM_LIT_OUTPUT_DIR "${COMPILER_RT_EXEC_OUTPUT_DIR}")
 endif()
 
 construct_compiler_rt_default_triple()
@@ -228,7 +229,7 @@ append_list_if(COMPILER_RT_DEBUG -DSANITIZER_DEBUG=1 SANITIZER_COMMON_CFLAGS)
 # always respect the optimization flags set by CMAKE_BUILD_TYPE instead.
 if (NOT MSVC)
 
-  # Build with optimization, unless we're in debug mode. 
+  # Build with optimization, unless we're in debug mode.
   if(COMPILER_RT_DEBUG)
     list(APPEND SANITIZER_COMMON_CFLAGS -O0)
   else()
@@ -348,4 +349,15 @@ add_subdirectory(lib)
 if(COMPILER_RT_INCLUDE_TESTS)
   add_subdirectory(unittests)
   add_subdirectory(test)
+  if (COMPILER_RT_STANDALONE_BUILD)
+    # If we have a valid source tree, generate llvm-lit into the bin directory.
+    # The user can still choose to have the check targets *use* a different lit
+    # by specifying -DLLVM_EXTERNAL_LIT, but we generate it regardless.
+    if (EXISTS ${LLVM_MAIN_SRC_DIR}/utils/llvm-lit)
+      add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/llvm-lit ${CMAKE_CURRENT_BINARY_DIR}/llvm-lit)
+    elseif(NOT EXISTS ${LLVM_EXTERNAL_LIT})
+      message(WARNING "Could not find LLVM source directory and LLVM_EXTERNAL_LIT does not"
+                       "point to a valid file.  You will not be able to run tests.")
+    endif()
+  endif()
 endif()
diff --git a/compiler-rt/test/lit.common.cfg b/compiler-rt/test/lit.common.cfg
index 4f23ab28550..6c07ca66195 100644
--- a/compiler-rt/test/lit.common.cfg
+++ b/compiler-rt/test/lit.common.cfg
@@ -73,10 +73,9 @@ for name in possibly_dangerous_env_vars:
     del config.environment[name]
 
 # Tweak PATH to include llvm tools dir.
-llvm_tools_dir = getattr(config, 'llvm_tools_dir', None)
-if (not llvm_tools_dir) or (not os.path.exists(llvm_tools_dir)):
-  lit_config.fatal("Invalid llvm_tools_dir config attribute: %r" % llvm_tools_dir)
-path = os.path.pathsep.join((llvm_tools_dir, config.environment['PATH']))
+if (not config.llvm_tools_dir) or (not os.path.exists(config.llvm_tools_dir)):
+  lit_config.fatal("Invalid llvm_tools_dir config attribute: %r" % config.llvm_tools_dir)
+path = os.path.pathsep.join((config.llvm_tools_dir, config.environment['PATH']))
 config.environment['PATH'] = path
 
 # Help MSVS link.exe find the standard libraries.
@@ -193,7 +192,7 @@ if config.host_os == 'Darwin':
 else:
   config.substitutions.append( ("%macos_min_target_10_11", "") )
 
-sancovcc_path = os.path.join(llvm_tools_dir, "sancov") 
+sancovcc_path = os.path.join(config.llvm_tools_dir, "sancov")
 if os.path.exists(sancovcc_path):
   config.available_features.add("has_sancovcc")
   config.substitutions.append( ("%sancovcc ", sancovcc_path) )
@@ -254,7 +253,7 @@ try:
       stdout = subprocess.PIPE,
       env=config.environment)
 except OSError:
-  print("Could not find llvm-config in " + llvm_tools_dir)
+  print("Could not find llvm-config in " + config.llvm_tools_dir)
   exit(42)
 
 if re.search(r'ON', llvm_config_cmd.stdout.read().decode('ascii')):
diff --git a/compiler-rt/test/profile/lit.cfg b/compiler-rt/test/profile/lit.cfg
index 9ca394212e9..7f0d95a9a39 100644
--- a/compiler-rt/test/profile/lit.cfg
+++ b/compiler-rt/test/profile/lit.cfg
@@ -22,17 +22,6 @@ if hasattr(config, 'profile_lit_binary_dir') and \
         config.profile_lit_binary_dir is not None:
     config.test_exec_root = os.path.join(config.profile_lit_binary_dir, config.name)
 
-# If the above check didn't work, we're probably in the source tree.  Use some
-# magic to re-execute from the build tree.
-if config.test_exec_root is None:
-    # The magic relies on knowing compilerrt_site_basedir.
-    compilerrt_basedir = lit_config.params.get('compilerrt_site_basedir', None)
-    if compilerrt_basedir:
-        site_cfg = os.path.join(compilerrt_basedir, 'profile', 'lit.site.cfg')
-        if os.path.exists(site_cfg):
-            lit_config.load_config(config, site_cfg)
-            raise SystemExit
-
 if config.host_os in ['Linux']:
   extra_link_flags = ["-ldl"]
 else:
diff --git a/compiler-rt/unittests/lit.common.unit.cfg b/compiler-rt/unittests/lit.common.unit.cfg
index b08c1fe1283..31206e913bf 100644
--- a/compiler-rt/unittests/lit.common.unit.cfg
+++ b/compiler-rt/unittests/lit.common.unit.cfg
@@ -16,7 +16,7 @@ config.test_format = lit.formats.GoogleTest(llvm_build_mode, "Test")
 config.suffixes = []
 
 # Tweak PATH to include llvm tools dir.
-llvm_tools_dir = getattr(config, 'llvm_tools_dir', None)
+llvm_tools_dir = config.llvm_tools_dir
 if (not llvm_tools_dir) or (not os.path.exists(llvm_tools_dir)):
   lit_config.fatal("Invalid llvm_tools_dir config attribute: %r" % llvm_tools_dir)
 path = os.path.pathsep.join((llvm_tools_dir, config.environment['PATH']))
diff --git a/lld/test/Unit/lit.cfg b/lld/test/Unit/lit.cfg
index 4bc973a58ed..dac9f5dc6c3 100644
--- a/lld/test/Unit/lit.cfg
+++ b/lld/test/Unit/lit.cfg
@@ -17,7 +17,21 @@ config.suffixes =  []
 config.test_source_root = os.path.join(config.lld_obj_root, 'unittests')
 config.test_exec_root = config.test_source_root
 
+
+# Tweak the PATH to include the tools dir.
+path = os.path.pathsep.join((config.lld_tools_dir, config.llvm_tools_dir, config.environment['PATH']))
+config.environment['PATH'] = path
+
+path = os.path.pathsep.join((config.lld_libs_dir, config.llvm_libs_dir,
+                              config.environment.get('LD_LIBRARY_PATH','')))
+config.environment['LD_LIBRARY_PATH'] = path
+
+# Propagate LLVM_SRC_ROOT into the environment.
+config.environment['LLVM_SRC_ROOT'] = config.llvm_src_root
+
+# Propagate PYTHON_EXECUTABLE into the environment
+config.environment['PYTHON_EXECUTABLE'] = sys.executable
+
+
 # testFormat: The test format to use to interpret tests.
-if not hasattr(config, 'llvm_build_mode'):
-    lit_config.fatal("unable to find llvm_build_mode value on config")
 config.test_format = lit.formats.GoogleTest(config.llvm_build_mode, 'Tests')
diff --git a/lld/test/Unit/lit.site.cfg.in b/lld/test/Unit/lit.site.cfg.in
index c2f3054a2d5..30e8933eb5f 100644
--- a/lld/test/Unit/lit.site.cfg.in
+++ b/lld/test/Unit/lit.site.cfg.in
@@ -8,6 +8,8 @@ config.llvm_build_mode = "@LLVM_BUILD_MODE@"
 config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@"
 config.lld_obj_root = "@LLD_BINARY_DIR@"
 config.lld_src_root = "@LLD_SOURCE_DIR@"
+config.lld_libs_dir = "@LLVM_LIBRARY_OUTPUT_INTDIR@"
+config.lld_tools_dir = "@LLVM_RUNTIME_OUTPUT_INTDIR@"
 config.target_triple = "@TARGET_TRIPLE@"
 config.python_executable = "@PYTHON_EXECUTABLE@"
 
diff --git a/lld/test/lit.cfg b/lld/test/lit.cfg
index 2a6cdd6341e..e27d0903d46 100644
--- a/lld/test/lit.cfg
+++ b/lld/test/lit.cfg
@@ -55,95 +55,23 @@ config.excludes = ['Inputs']
 # test_source_root: The root path where tests are located.
 config.test_source_root = os.path.dirname(__file__)
 
-# test_exec_root: The root path where tests should be run.
-lld_obj_root = getattr(config, 'lld_obj_root', None)
-if lld_obj_root is not None:
-    config.test_exec_root = os.path.join(lld_obj_root, 'test')
+config.test_exec_root = os.path.join(config.lld_obj_root, 'test')
 
-# Set llvm_{src,obj}_root for use by others.
-config.llvm_src_root = getattr(config, 'llvm_src_root', None)
-config.llvm_obj_root = getattr(config, 'llvm_obj_root', None)
 
 # Tweak the PATH to include the tools dir and the scripts dir.
-if lld_obj_root is not None:
-    lld_tools_dir = getattr(config, 'lld_tools_dir', None)
-    if not lld_tools_dir:
-        lit_config.fatal('No LLD tools dir set!')
-    llvm_tools_dir = getattr(config, 'llvm_tools_dir', None)
-    if not llvm_tools_dir:
-        lit_config.fatal('No LLVM tools dir set!')
-    path = os.path.pathsep.join((lld_tools_dir, llvm_tools_dir, config.environment['PATH']))
-    path = os.path.pathsep.join((os.path.join(getattr(config, 'llvm_src_root', None),'test','Scripts'),path))
-
-    config.environment['PATH'] = path
-
-    lld_libs_dir = getattr(config, 'lld_libs_dir', None)
-    if not lld_libs_dir:
-        lit_config.fatal('No LLD libs dir set!')
-    llvm_libs_dir = getattr(config, 'llvm_libs_dir', None)
-    if not llvm_libs_dir:
-        lit_config.fatal('No LLVM libs dir set!')
-    path = os.path.pathsep.join((lld_libs_dir, llvm_libs_dir,
-                                 config.environment.get('LD_LIBRARY_PATH','')))
-    config.environment['LD_LIBRARY_PATH'] = path
-
-    # Propagate LLVM_SRC_ROOT into the environment.
-    config.environment['LLVM_SRC_ROOT'] = getattr(config, 'llvm_src_root', '')
-
-    # Propagate PYTHON_EXECUTABLE into the environment
-    config.environment['PYTHON_EXECUTABLE'] = getattr(config, 'python_executable',
-                                                      '')
-###
+path = os.path.pathsep.join((config.lld_tools_dir, config.llvm_tools_dir, config.environment['PATH']))
+
+config.environment['PATH'] = path
+
+path = os.path.pathsep.join((config.lld_libs_dir, config.llvm_libs_dir,
+                              config.environment.get('LD_LIBRARY_PATH','')))
+config.environment['LD_LIBRARY_PATH'] = path
+
+# Propagate LLVM_SRC_ROOT into the environment.
+config.environment['LLVM_SRC_ROOT'] = config.llvm_src_root
 
-# Check that the object root is known.
-if config.test_exec_root is None:
-    # Otherwise, we haven't loaded the site specific configuration (the user is
-    # probably trying to run on a test file directly, and either the site
-    # configuration hasn't been created by the build system, or we are in an
-    # out-of-tree build situation).
-
-    # Check for 'lld_site_config' user parameter, and use that if available.
-    site_cfg = lit_config.params.get('lld_site_config', None)
-    if site_cfg and os.path.exists(site_cfg):
-        lit_config.load_config(config, site_cfg)
-        raise SystemExit
-
-    # Try to detect the situation where we are using an out-of-tree build by
-    # looking for 'llvm-config'.
-    #
-    # FIXME: I debated (i.e., wrote and threw away) adding logic to
-    # automagically generate the lit.site.cfg if we are in some kind of fresh
-    # build situation. This means knowing how to invoke the build system though,
-    # and I decided it was too much magic. We should solve this by just having
-    # the .cfg files generated during the configuration step.
-
-    llvm_config = lit.util.which('llvm-config', config.environment['PATH'])
-    if not llvm_config:
-        lit_config.fatal('No site specific configuration available!')
-
-    # Get the source and object roots.
-    llvm_src_root = subprocess.check_output(['llvm-config', '--src-root']).strip()
-    llvm_obj_root = subprocess.check_output(['llvm-config', '--obj-root']).strip()
-    lld_src_root = os.path.join(llvm_src_root, "tools", "lld")
-    lld_obj_root = os.path.join(llvm_obj_root, "tools", "lld")
-
-    # Validate that we got a tree which points to here, using the standard
-    # tools/lld layout.
-    this_src_root = os.path.dirname(config.test_source_root)
-    if os.path.realpath(lld_src_root) != os.path.realpath(this_src_root):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Check that the site specific configuration exists.
-    site_cfg = os.path.join(lld_obj_root, 'test', 'lit.site.cfg')
-    if not os.path.exists(site_cfg):
-        lit_config.fatal(
-            'No site specific configuration available! You may need to '
-            'run "make test" in your lld build directory.')
-
-    # Okay, that worked. Notify the user of the automagic, and reconfigure.
-    lit_config.note('using out-of-tree build at %r' % lld_obj_root)
-    lit_config.load_config(config, site_cfg)
-    raise SystemExit
+# Propagate PYTHON_EXECUTABLE into the environment
+config.environment['PYTHON_EXECUTABLE'] = sys.executable
 
 # For each occurrence of a lld tool name as its own word, replace it
 # with the full path to the build directory holding that tool.  This
@@ -185,7 +113,7 @@ for pattern in tool_patterns:
     if not tool_path:
         # Warn, but still provide a substitution.
         lit_config.note('Did not find ' + tool_name + ' in ' + path)
-        tool_path = llvm_tools_dir + '/' + tool_name
+        tool_path = config.llvm_tools_dir + '/' + tool_name
     config.substitutions.append((pattern, tool_pipe + tool_path))
 
 # Add site-specific substitutions.
@@ -227,11 +155,11 @@ if platform.system() not in ['Windows']:
 import subprocess
 try:
     llvm_config_cmd = \
-     subprocess.Popen([os.path.join(llvm_tools_dir, 'llvm-config'),
+     subprocess.Popen([os.path.join(config.llvm_tools_dir, 'llvm-config'),
                      '--build-mode', '--assertion-mode', '--targets-built'],
                       stdout = subprocess.PIPE)
 except OSError as why:
-    print("Could not find llvm-config in " + llvm_tools_dir)
+    print("Could not find llvm-config in " + config.llvm_tools_dir)
     exit(42)
 
 llvm_config_output = llvm_config_cmd.stdout.read().decode('utf_8')
diff --git a/lldb/lit/Unit/lit.cfg b/lldb/lit/Unit/lit.cfg
index 7dfb344e6fa..338adfd7bd9 100644
--- a/lldb/lit/Unit/lit.cfg
+++ b/lldb/lit/Unit/lit.cfg
@@ -6,19 +6,6 @@ import os
 
 import lit.formats
 
-# Check that the object root is known.
-if config.test_exec_root is None:
-    # Otherwise, we haven't loaded the site specific configuration (the user is
-    # probably trying to run on a test file directly, and either the site
-    # configuration hasn't been created by the build system, or we are in an
-    # out-of-tree build situation).
-
-    # Check for 'llvm_unit_site_config' user parameter, and use that if available.
-    site_cfg = lit_config.params.get('lldb_unit_site_config', None)
-    if site_cfg and os.path.exists(site_cfg):
-        lit_config.load_config(config, site_cfg)
-        raise SystemExit
-
 # name: The name of this test suite.
 config.name = 'lldb-Unit'
 
@@ -31,6 +18,4 @@ config.test_source_root = os.path.join(config.lldb_obj_root, 'unittests')
 config.test_exec_root = config.test_source_root
 
 # testFormat: The test format to use to interpret tests.
-if not hasattr(config, 'llvm_build_mode'):
-    lit_config.fatal("unable to find llvm_build_mode value on config")
 config.test_format = lit.formats.GoogleTest(config.llvm_build_mode, 'Tests')
diff --git a/lldb/lit/lit.cfg b/lldb/lit/lit.cfg
index 8dea61b2716..51f795313f3 100644
--- a/lldb/lit/lit.cfg
+++ b/lldb/lit/lit.cfg
@@ -29,94 +29,24 @@ config.suffixes = []
 config.test_source_root = os.path.dirname(__file__)
 
 # test_exec_root: The root path where tests should be run.
-lldb_obj_root = getattr(config, 'lldb_obj_root', None)
-if lldb_obj_root is not None:
-    config.test_exec_root = os.path.join(lldb_obj_root, 'lit')
-
-# Set llvm_{src,obj}_root for use by others.
-config.llvm_src_root = getattr(config, 'llvm_src_root', None)
-config.llvm_obj_root = getattr(config, 'llvm_obj_root', None)
+config.test_exec_root = os.path.join(config.lldb_obj_root, 'lit')
 
 # Tweak the PATH to include the tools dir and the scripts dir.
-if lldb_obj_root is not None:
-    lldb_tools_dir = getattr(config, 'lldb_tools_dir', None)
-    if not lldb_tools_dir:
-        lit_config.fatal('No LLDB tools dir set!')
-    llvm_tools_dir = getattr(config, 'llvm_tools_dir', None)
-    if not llvm_tools_dir:
-        lit_config.fatal('No LLVM tools dir set!')
-    path = os.path.pathsep.join((lldb_tools_dir, llvm_tools_dir, config.environment['PATH']))
-    path = os.path.pathsep.join((os.path.join(getattr(config, 'llvm_src_root', None),'test','Scripts'),path))
-
-    config.environment['PATH'] = path
-
-    lldb_libs_dir = getattr(config, 'lldb_libs_dir', None)
-    if not lldb_libs_dir:
-        lit_config.fatal('No LLDB libs dir set!')
-    llvm_libs_dir = getattr(config, 'llvm_libs_dir', None)
-    if not llvm_libs_dir:
-        lit_config.fatal('No LLVM libs dir set!')
-    path = os.path.pathsep.join((lldb_libs_dir, llvm_libs_dir,
-                                 config.environment.get('LD_LIBRARY_PATH','')))
-    config.environment['LD_LIBRARY_PATH'] = path
-
-    # Propagate LLVM_SRC_ROOT into the environment.
-    config.environment['LLVM_SRC_ROOT'] = getattr(config, 'llvm_src_root', '')
-
-    # Propagate PYTHON_EXECUTABLE into the environment
-    config.environment['PYTHON_EXECUTABLE'] = getattr(config, 'python_executable',
-                                                      '')
-###
-
-# Check that the object root is known.
-if config.test_exec_root is None:
-    # Otherwise, we haven't loaded the site specific configuration (the user is
-    # probably trying to run on a test file directly, and either the site
-    # configuration hasn't been created by the build system, or we are in an
-    # out-of-tree build situation).
-
-    # Check for 'lldb_site_config' user parameter, and use that if available.
-    site_cfg = lit_config.params.get('lldb_site_config', None)
-    if site_cfg and os.path.exists(site_cfg):
-        lit_config.load_config(config, site_cfg)
-        raise SystemExit
-
-    # Try to detect the situation where we are using an out-of-tree build by
-    # looking for 'llvm-config'.
-    #
-    # FIXME: I debated (i.e., wrote and threw away) adding logic to
-    # automagically generate the lit.site.cfg if we are in some kind of fresh
-    # build situation. This means knowing how to invoke the build system though,
-    # and I decided it was too much magic. We should solve this by just having
-    # the .cfg files generated during the configuration step.
-
-    llvm_config = lit.util.which('llvm-config', config.environment['PATH'])
-    if not llvm_config:
-        lit_config.fatal('No site specific configuration available!')
-
-    # Get the source and object roots.
-    llvm_src_root = subprocess.check_output(['llvm-config', '--src-root']).strip()
-    llvm_obj_root = subprocess.check_output(['llvm-config', '--obj-root']).strip()
-    lldb_src_root = os.path.join(llvm_src_root, "tools", "lldb")
-    lldb_obj_root = os.path.join(llvm_obj_root, "tools", "lldb")
-
-    # Validate that we got a tree which points to here, using the standard
-    # tools/lldb layout.
-    this_src_root = os.path.dirname(config.test_source_root)
-    if os.path.realpath(lldb_src_root) != os.path.realpath(this_src_root):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Check that the site specific configuration exists.
-    site_cfg = os.path.join(lldb_obj_root, 'test', 'lit.site.cfg')
-    if not os.path.exists(site_cfg):
-        lit_config.fatal(
-            'No site specific configuration available! You may need to '
-            'run "make test" in your lldb build directory.')
-
-    # Okay, that worked. Notify the user of the automagic, and reconfigure.
-    lit_config.note('using out-of-tree build at %r' % lldb_obj_root)
-    lit_config.load_config(config, site_cfg)
-    raise SystemExit
+lldb_tools_dir = config.lldb_tools_dir
+llvm_tools_dir = config.llvm_tools_dir
+path = os.path.pathsep.join((config.lldb_tools_dir, config.llvm_tools_dir, config.environment['PATH']))
+
+config.environment['PATH'] = path
+
+path = os.path.pathsep.join((config.lldb_libs_dir, config.llvm_libs_dir,
+                              config.environment.get('LD_LIBRARY_PATH','')))
+config.environment['LD_LIBRARY_PATH'] = path
+
+# Propagate LLVM_SRC_ROOT into the environment.
+config.environment['LLVM_SRC_ROOT'] = getattr(config, 'llvm_src_root', '')
+
+# Propagate PYTHON_EXECUTABLE into the environment
+config.environment['PYTHON_EXECUTABLE'] = getattr(config, 'python_executable', '')
 
 # Register substitutions
 config.substitutions.append(('%python', config.python_executable))
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index d08fd67ddaf..76d66b99fc8 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -845,7 +845,6 @@ if( LLVM_INCLUDE_UTILS )
   add_subdirectory(utils/PerfectShuffle)
   add_subdirectory(utils/count)
   add_subdirectory(utils/not)
-  add_subdirectory(utils/llvm-lit)
   add_subdirectory(utils/yaml-bench)
 else()
   if ( LLVM_INCLUDE_TESTS )
@@ -932,6 +931,11 @@ endif()
 
 add_subdirectory(cmake/modules)
 
+# Do this last so that all lit targets have already been created.
+if (LLVM_INCLUDE_UTILS)
+  add_subdirectory(utils/llvm-lit)
+endif()
+
 if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
   install(DIRECTORY include/llvm include/llvm-c
     DESTINATION include
diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
index 66abb2486d9..54807dc81c4 100644
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -687,7 +687,7 @@ macro(add_llvm_executable name)
     # it forces Xcode to properly link the static library.
     list(APPEND ALL_FILES "${LLVM_MAIN_SRC_DIR}/cmake/dummy.cpp")
   endif()
-  
+
   if( EXCLUDE_FROM_ALL )
     add_executable(${name} EXCLUDE_FROM_ALL ${ALL_FILES})
   else()
@@ -1174,6 +1174,60 @@ function(configure_lit_site_cfg input output)
   endif()
 
   configure_file(${input} ${output} @ONLY)
+  get_filename_component(INPUT_DIR ${input} DIRECTORY)
+  if (EXISTS "${INPUT_DIR}/lit.cfg")
+    set(PYTHON_STATEMENT "map_config('${INPUT_DIR}/lit.cfg', '${output}')")
+    get_property(LLVM_LIT_CONFIG_MAP GLOBAL PROPERTY LLVM_LIT_CONFIG_MAP)
+    set(LLVM_LIT_CONFIG_MAP "${LLVM_LIT_CONFIG_MAP}\n${PYTHON_STATEMENT}")
+    set_property(GLOBAL PROPERTY LLVM_LIT_CONFIG_MAP ${LLVM_LIT_CONFIG_MAP})
+  endif()
+endfunction()
+
+function(get_llvm_lit_path base_dir file_name)
+  cmake_parse_arguments(ARG "ALLOW_EXTERNAL" "" "" ${ARGN})
+
+  if (ARG_ALLOW_EXTERNAL)
+    set (LLVM_EXTERNAL_LIT "" CACHE STRING "Command used to spawn lit")
+    if (NOT "${LLVM_EXTERNAL_LIT}" STREQUAL "")
+      if (EXISTS ${LLVM_EXTERNAL_LIT})
+        get_filename_component(LIT_FILE_NAME ${LLVM_EXTERNAL_LIT} NAME)
+        get_filename_component(LIT_BASE_DIR ${LLVM_EXTERNAL_LIT} DIRECTORY)
+        set(${file_name} ${LIT_FILE_NAME} PARENT_SCOPE)
+        set(${base_dir} ${LIT_BASE_DIR} PARENT_SCOPE)
+        return()
+      else()
+        message(WARN "LLVM_EXTERNAL_LIT set to ${LLVM_EXTERNAL_LIT}, but the path does not exist.")
+      endif()
+    endif()
+  endif()
+
+  set(lit_file_name "llvm-lit")
+  if (WIN32 AND NOT CYGWIN)
+    # llvm-lit needs suffix.py for multiprocess to find a main module.
+    set(lit_file_name "${lit_file_name}.py")
+  endif ()
+  set(${file_name} ${lit_file_name} PARENT_SCOPE)
+
+  get_property(LLVM_LIT_BASE_DIR GLOBAL PROPERTY LLVM_LIT_BASE_DIR)
+  if (NOT "${LLVM_LIT_BASE_DIR}" STREQUAL "")
+    set(${base_dir} ${LLVM_LIT_BASE_DIR} PARENT_SCOPE)
+  endif()
+
+  # Allow individual projects to provide an override
+  if (NOT "${LLVM_LIT_OUTPUT_DIR}" STREQUAL "")
+    set(LLVM_LIT_BASE_DIR ${LLVM_LIT_OUTPUT_DIR})
+  elseif(NOT "${LLVM_RUNTIME_OUTPUT_INTDIR}" STREQUAL "")
+    set(LLVM_LIT_BASE_DIR ${LLVM_RUNTIME_OUTPUT_INTDIR})
+  else()
+    message(WARNING "Could not find suitable output location for llvm-lit."
+                    "Using default ${CMAKE_CURRENT_BINARY_DIR}/llvm-lit")
+    set(LLVM_LIT_BASE_DIR ${CMAKE_CURRENT_BINARY_DIR}/llvm-lit)
+  endif()
+
+  # Cache this so we don't have to do it again and have subsequent calls
+  # potentially disagree on the value.
+  set_property(GLOBAL PROPERTY LLVM_LIT_BASE_DIR ${LLVM_LIT_BASE_DIR})
+  set(${base_dir} ${LLVM_LIT_BASE_DIR} PARENT_SCOPE)
 endfunction()
 
 # A raw function to create a lit target. This is used to implement the testuite
@@ -1185,12 +1239,16 @@ function(add_lit_target target comment)
   if (NOT CMAKE_CFG_INTDIR STREQUAL ".")
     list(APPEND LIT_ARGS --param build_mode=${CMAKE_CFG_INTDIR})
   endif ()
-  if (EXISTS ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
-    set (LIT_COMMAND "${PYTHON_EXECUTABLE};${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py"
-         CACHE STRING "Command used to spawn llvm-lit")
-  else()
-    find_program(LIT_COMMAND NAMES llvm-lit lit.py lit)
-  endif ()
+
+  # Get the path to the lit to *run* tests with.  This can be overriden by
+  # the user by specifying -DLLVM_EXTERNAL_LIT=<path-to-lit.py>
+  get_llvm_lit_path(
+    lit_base_dir
+    lit_file_name
+    ALLOW_EXTERNAL
+    )
+
+  set(LIT_COMMAND "${PYTHON_EXECUTABLE};${lit_base_dir}/${lit_file_name}")
   list(APPEND LIT_COMMAND ${LIT_ARGS})
   foreach(param ${ARG_PARAMS})
     list(APPEND LIT_COMMAND --param ${param})
@@ -1350,7 +1408,7 @@ function(add_llvm_tool_symlink link_name target)
   # magic. First we grab one of the types, and a type-specific path. Then from
   # the type-specific path we find the last occurrence of the type in the path,
   # and replace it with CMAKE_CFG_INTDIR. This allows the build step to be type
-  # agnostic again. 
+  # agnostic again.
   if(NOT ARG_OUTPUT_DIR)
     # If you're not overriding the OUTPUT_DIR, we can make the link relative in
     # the same directory.
diff --git a/llvm/test/Unit/lit.cfg b/llvm/test/Unit/lit.cfg
index 9da82f5f2c9..609408d1dd8 100644
--- a/llvm/test/Unit/lit.cfg
+++ b/llvm/test/Unit/lit.cfg
@@ -18,14 +18,11 @@ config.is_early = True
 
 # test_source_root: The root path where tests are located.
 # test_exec_root: The root path where tests should be run.
-llvm_obj_root = getattr(config, 'llvm_obj_root', None)
-if llvm_obj_root is not None:
-    config.test_exec_root = os.path.join(llvm_obj_root, 'unittests')
-    config.test_source_root = config.test_exec_root
+config.test_exec_root = os.path.join(config.llvm_obj_root, 'unittests')
+config.test_source_root = config.test_exec_root
 
 # testFormat: The test format to use to interpret tests.
-llvm_build_mode = getattr(config, 'llvm_build_mode', "Debug")
-config.test_format = lit.formats.GoogleTest(llvm_build_mode, 'Tests')
+config.test_format = lit.formats.GoogleTest(config.llvm_build_mode, 'Tests')
 
 # Propagate the temp directory. Windows requires this because it uses \Windows\
 # if none of these are present.
@@ -47,49 +44,3 @@ if sys.platform in ['win32', 'cygwin'] and os.path.isdir(config.shlibdir):
 # Win32 may use %SYSTEMDRIVE% during file system shell operations, so propogate.
 if sys.platform == 'win32' and 'SYSTEMDRIVE' in os.environ:
     config.environment['SYSTEMDRIVE'] = os.environ['SYSTEMDRIVE']
-
-###
-
-# Check that the object root is known.
-if config.test_exec_root is None:
-    # Otherwise, we haven't loaded the site specific configuration (the user is
-    # probably trying to run on a test file directly, and either the site
-    # configuration hasn't been created by the build system, or we are in an
-    # out-of-tree build situation).
-
-    # Check for 'llvm_unit_site_config' user parameter, and use that if available.
-    site_cfg = lit_config.params.get('llvm_unit_site_config', None)
-    if site_cfg and os.path.exists(site_cfg):
-        lit_config.load_config(config, site_cfg)
-        raise SystemExit
-
-    # Try to detect the situation where we are using an out-of-tree build by
-    # looking for 'llvm-config'.
-    #
-    # FIXME: I debated (i.e., wrote and threw away) adding logic to
-    # automagically generate the lit.site.cfg if we are in some kind of fresh
-    # build situation. This means knowing how to invoke the build system
-    # though, and I decided it was too much magic.
-
-    llvm_config = lit.util.which('llvm-config', config.environment['PATH'])
-    if not llvm_config:
-        lit_config.fatal('No site specific configuration available!')
-
-    # Get the source and object roots.
-    llvm_src_root = subprocess.check_output(['llvm-config', '--src-root']).strip()
-    llvm_obj_root = subprocess.check_output(['llvm-config', '--obj-root']).strip()
-
-    # Validate that we got a tree which points to here.
-    this_src_root = os.path.join(os.path.dirname(__file__),'..','..')
-    if os.path.realpath(llvm_src_root) != os.path.realpath(this_src_root):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Check that the site specific configuration exists.
-    site_cfg = os.path.join(llvm_obj_root, 'test', 'Unit', 'lit.site.cfg')
-    if not os.path.exists(site_cfg):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Okay, that worked. Notify the user of the automagic, and reconfigure.
-    lit_config.note('using out-of-tree build at %r' % llvm_obj_root)
-    lit_config.load_config(config, site_cfg)
-    raise SystemExit
diff --git a/llvm/test/lit.cfg b/llvm/test/lit.cfg
index 7d298f64a5f..05176dc6711 100644
--- a/llvm/test/lit.cfg
+++ b/llvm/test/lit.cfg
@@ -53,17 +53,11 @@ config.excludes = ['Inputs', 'CMakeLists.txt', 'README.txt', 'LICENSE.txt']
 config.test_source_root = os.path.dirname(__file__)
 
 # test_exec_root: The root path where tests should be run.
-llvm_obj_root = getattr(config, 'llvm_obj_root', None)
-if llvm_obj_root is not None:
-    config.test_exec_root = os.path.join(llvm_obj_root, 'test')
+config.test_exec_root = os.path.join(config.llvm_obj_root, 'test')
 
 # Tweak the PATH to include the tools dir.
-if llvm_obj_root is not None:
-    llvm_tools_dir = getattr(config, 'llvm_tools_dir', None)
-    if not llvm_tools_dir:
-        lit_config.fatal('No LLVM tools dir set!')
-    path = os.path.pathsep.join((llvm_tools_dir, config.environment['PATH']))
-    config.environment['PATH'] = path
+path = os.path.pathsep.join((config.llvm_tools_dir, config.environment['PATH']))
+config.environment['PATH'] = path
 
 # Propagate 'HOME' through the environment.
 if 'HOME' in os.environ:
@@ -85,7 +79,7 @@ if 'TEMP' in os.environ:
     config.environment['TEMP'] = os.environ['TEMP']
 
 # Propagate LLVM_SRC_ROOT into the environment.
-config.environment['LLVM_SRC_ROOT'] = getattr(config, 'llvm_src_root', '')
+config.environment['LLVM_SRC_ROOT'] = config.llvm_src_root
 
 # Propagate PYTHON_EXECUTABLE into the environment
 config.environment['PYTHON_EXECUTABLE'] = getattr(config, 'python_executable',
@@ -97,80 +91,23 @@ for symbolizer in ['ASAN_SYMBOLIZER_PATH', 'MSAN_SYMBOLIZER_PATH']:
         config.environment[symbolizer] = os.environ[symbolizer]
 
 # Set up OCAMLPATH to include newly built OCaml libraries.
-llvm_lib_dir = getattr(config, 'llvm_lib_dir', None)
-if llvm_lib_dir is None:
-    if llvm_obj_root is not None:
-        llvm_lib_dir = os.path.join(llvm_obj_root, 'lib')
-
-if llvm_lib_dir is not None:
-    top_ocaml_lib = os.path.join(llvm_lib_dir, 'ocaml')
-    llvm_ocaml_lib = os.path.join(top_ocaml_lib, 'llvm')
-    if llvm_ocaml_lib is not None:
-        ocamlpath = os.path.pathsep.join((llvm_ocaml_lib, top_ocaml_lib))
-        if 'OCAMLPATH' in os.environ:
-            ocamlpath = os.path.pathsep.join((ocamlpath, os.environ['OCAMLPATH']))
-        config.environment['OCAMLPATH'] = ocamlpath
-
-        if 'CAML_LD_LIBRARY_PATH' in os.environ:
-            caml_ld_library_path = os.path.pathsep.join((llvm_ocaml_lib,
-                                        os.environ['CAML_LD_LIBRARY_PATH']))
-            config.environment['CAML_LD_LIBRARY_PATH'] = caml_ld_library_path
-        else:
-            config.environment['CAML_LD_LIBRARY_PATH'] = llvm_ocaml_lib
+top_ocaml_lib = os.path.join(config.llvm_lib_dir, 'ocaml')
+llvm_ocaml_lib = os.path.join(top_ocaml_lib, 'llvm')
+ocamlpath = os.path.pathsep.join((llvm_ocaml_lib, top_ocaml_lib))
+if 'OCAMLPATH' in os.environ:
+    ocamlpath = os.path.pathsep.join((ocamlpath, os.environ['OCAMLPATH']))
+config.environment['OCAMLPATH'] = ocamlpath
+
+if 'CAML_LD_LIBRARY_PATH' in os.environ:
+    caml_ld_library_path = os.path.pathsep.join((llvm_ocaml_lib,
+                                os.environ['CAML_LD_LIBRARY_PATH']))
+    config.environment['CAML_LD_LIBRARY_PATH'] = caml_ld_library_path
+else:
+    config.environment['CAML_LD_LIBRARY_PATH'] = llvm_ocaml_lib
 
 # Set up OCAMLRUNPARAM to enable backtraces in OCaml tests.
 config.environment['OCAMLRUNPARAM'] = 'b'
 
-###
-
-import os
-
-# Check that the object root is known.
-if config.test_exec_root is None:
-    # Otherwise, we haven't loaded the site specific configuration (the user is
-    # probably trying to run on a test file directly, and either the site
-    # configuration hasn't been created by the build system, or we are in an
-    # out-of-tree build situation).
-
-    # Check for 'llvm_site_config' user parameter, and use that if available.
-    site_cfg = lit_config.params.get('llvm_site_config', None)
-    if site_cfg and os.path.exists(site_cfg):
-        lit_config.load_config(config, site_cfg)
-        raise SystemExit
-
-    # Try to detect the situation where we are using an out-of-tree build by
-    # looking for 'llvm-config'.
-    #
-    # FIXME: I debated (i.e., wrote and threw away) adding logic to
-    # automagically generate the lit.site.cfg if we are in some kind of fresh
-    # build situation. This means knowing how to invoke the build system
-    # though, and I decided it was too much magic.
-
-    llvm_config = lit.util.which('llvm-config', config.environment['PATH'])
-    if not llvm_config:
-        lit_config.fatal('No site specific configuration available!')
-
-    # Get the source and object roots.
-    llvm_src_root = subprocess.check_output(['llvm-config', '--src-root']).strip()
-    llvm_obj_root = subprocess.check_output(['llvm-config', '--obj-root']).strip()
-
-    # Validate that we got a tree which points to here.
-    this_src_root = os.path.dirname(config.test_source_root)
-    if os.path.realpath(llvm_src_root) != os.path.realpath(this_src_root):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Check that the site specific configuration exists.
-    site_cfg = os.path.join(llvm_obj_root, 'test', 'lit.site.cfg')
-    if not os.path.exists(site_cfg):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Okay, that worked. Notify the user of the automagic, and reconfigure.
-    lit_config.note('using out-of-tree build at %r' % llvm_obj_root)
-    lit_config.load_config(config, site_cfg)
-    raise SystemExit
-
-###
-
 # Provide the path to asan runtime lib 'libclang_rt.asan_osx_dynamic.dylib' if
 # available. This is darwin specific since it's currently only needed on darwin.
 def get_asan_rtlib():
@@ -231,11 +168,11 @@ config.substitutions.append( ('%ld64', ld64_cmd) )
 # Support tests for both native and bytecode builds.
 config.substitutions.append( ('%ocamlc',
     "%s ocamlc -cclib -L%s %s" %
-        (config.ocamlfind_executable, llvm_lib_dir, config.ocaml_flags)) )
+        (config.ocamlfind_executable, config.llvm_lib_dir, config.ocaml_flags)) )
 if config.have_ocamlopt:
     config.substitutions.append( ('%ocamlopt',
         "%s ocamlopt -cclib -L%s -cclib -Wl,-rpath,%s %s" %
-            (config.ocamlfind_executable, llvm_lib_dir, llvm_lib_dir, config.ocaml_flags)) )
+            (config.ocamlfind_executable, config.llvm_lib_dir, config.llvm_lib_dir, config.ocaml_flags)) )
 else:
     config.substitutions.append( ('%ocamlopt', "true" ) )
 
@@ -267,7 +204,7 @@ def find_tool_substitution(pattern):
     # llvm-lit "-Dllc=llc -enable-misched -verify-machineinstrs"
     tool_path = lit_config.params.get(tool_name)
     if tool_path is None:
-        tool_path = lit.util.which(tool_name, llvm_tools_dir)
+        tool_path = lit.util.which(tool_name, config.llvm_tools_dir)
         if tool_path is None:
             return tool_name, tool_path, tool_pipe
     if (tool_name == "llc" and
@@ -333,8 +270,8 @@ for pattern in [r"\bbugpoint\b(?!-)",
     tool_name, tool_path, tool_pipe = find_tool_substitution(pattern)
     if not tool_path:
         # Warn, but still provide a substitution.
-        lit_config.note('Did not find ' + tool_name + ' in ' + llvm_tools_dir)
-        tool_path = llvm_tools_dir + '/' + tool_name
+        lit_config.note('Did not find ' + tool_name + ' in ' + config.llvm_tools_dir)
+        tool_path = config.llvm_tools_dir + '/' + tool_name
     config.substitutions.append((pattern, tool_pipe + tool_path))
 
 # For tools that are optional depending on the config, we won't warn
@@ -350,7 +287,7 @@ for pattern in [r"\bllvm-go\b",
     tool_name, tool_path, tool_pipe = find_tool_substitution(pattern)
     if not tool_path:
         # Provide a substitution anyway, for the sake of consistent errors.
-        tool_path = llvm_tools_dir + '/' + tool_name
+        tool_path = config.llvm_tools_dir + '/' + tool_name
     config.substitutions.append((pattern, tool_pipe + tool_path))
 
 
@@ -482,11 +419,11 @@ if have_ld64_plugin_support():
 # Ask llvm-config about assertion mode.
 try:
     llvm_config_cmd = subprocess.Popen(
-        [os.path.join(llvm_tools_dir, 'llvm-config'), '--assertion-mode'],
+        [os.path.join(config.llvm_tools_dir, 'llvm-config'), '--assertion-mode'],
         stdout = subprocess.PIPE,
         env=config.environment)
 except OSError:
-    print("Could not find llvm-config in " + llvm_tools_dir)
+    print("Could not find llvm-config in " + config.llvm_tools_dir)
     exit(42)
 
 if re.search(r'ON', llvm_config_cmd.stdout.read().decode('ascii')):
@@ -538,11 +475,11 @@ if use_gmalloc:
 # Ask llvm-config about global-isel.
 try:
     llvm_config_cmd = subprocess.Popen(
-        [os.path.join(llvm_tools_dir, 'llvm-config'), '--has-global-isel'],
+        [os.path.join(config.llvm_tools_dir, 'llvm-config'), '--has-global-isel'],
         stdout = subprocess.PIPE,
         env=config.environment)
 except OSError:
-    print("Could not find llvm-config in " + llvm_tools_dir)
+    print("Could not find llvm-config in " + config.llvm_tools_dir)
     exit(42)
 
 if re.search(r'ON', llvm_config_cmd.stdout.read().decode('ascii')):
diff --git a/llvm/utils/lit/lit/discovery.py b/llvm/utils/lit/lit/discovery.py
index 8876dcba8f2..3b5d0517cff 100644
--- a/llvm/utils/lit/lit/discovery.py
+++ b/llvm/utils/lit/lit/discovery.py
@@ -40,6 +40,20 @@ def getTestSuite(item, litConfig, cache):
             ts, relative = search(parent)
             return (ts, relative + (base,))
 
+        # This is a private builtin parameter which can be used to perform
+        # translation of configuration paths.  Specifically, this parameter
+        # can be set to a dictionary that the discovery process will consult
+        # when it finds a configuration it is about to load.  If the given
+        # path is in the map, the value of that key is a path to the
+        # configuration to load instead.
+        config_map = litConfig.params.get('config_map')
+        if config_map:
+            cfgpath = os.path.normpath(cfgpath)
+            cfgpath = os.path.normcase(cfgpath)
+            target = config_map.get(cfgpath)
+            if target:
+                cfgpath = target
+
         # We found a test suite, create a new config for it and load it.
         if litConfig.debug:
             litConfig.note('loading suite config %r' % cfgpath)
@@ -212,7 +226,7 @@ def find_tests_for_inputs(lit_config, inputs):
                 f.close()
         else:
             actual_inputs.append(input)
-                    
+
     # Load the tests from the inputs.
     tests = []
     test_suite_cache = {}
diff --git a/llvm/utils/lit/tests/lit.cfg b/llvm/utils/lit/tests/lit.cfg
index 0c98299285a..f2ecaa6d417 100644
--- a/llvm/utils/lit/tests/lit.cfg
+++ b/llvm/utils/lit/tests/lit.cfg
@@ -65,7 +65,6 @@ if sys.platform.startswith('win') or sys.platform.startswith('cygwin'):
     config.available_features.add('windows')
 
 # Add llvm tools directory if this config is being loaded indirectly
-llvm_tools_dir = getattr(config, 'llvm_tools_dir', None)
-if llvm_tools_dir != None:
-    path = os.path.pathsep.join((llvm_tools_dir, config.environment['PATH']))
+if config.llvm_tools_dir is not None:
+    path = os.path.pathsep.join((config.llvm_tools_dir, config.environment['PATH']))
     config.environment['PATH'] = path
diff --git a/llvm/utils/llvm-lit/CMakeLists.txt b/llvm/utils/llvm-lit/CMakeLists.txt
index 4b10354cfde..670175c8185 100644
--- a/llvm/utils/llvm-lit/CMakeLists.txt
+++ b/llvm/utils/llvm-lit/CMakeLists.txt
@@ -1,12 +1,13 @@
-if (WIN32 AND NOT CYGWIN)
-  # llvm-lit needs suffix.py for multiprocess to find a main module.
-  set(suffix .py)
-endif ()
-set(llvm_lit_path ${LLVM_RUNTIME_OUTPUT_INTDIR}/llvm-lit${suffix})
+get_property(LLVM_LIT_CONFIG_MAP GLOBAL PROPERTY LLVM_LIT_CONFIG_MAP)
+
+get_llvm_lit_path(LIT_BASE_DIR LIT_FILE_NAME)
+
+set(LLVM_SOURCE_DIR ${LLVM_MAIN_SRC_DIR})
 
 if(NOT "${CMAKE_CFG_INTDIR}" STREQUAL ".")
   foreach(BUILD_MODE ${CMAKE_CONFIGURATION_TYPES})
-    string(REPLACE ${CMAKE_CFG_INTDIR} ${BUILD_MODE} bi ${llvm_lit_path})
+    string(REPLACE ${CMAKE_CFG_INTDIR} ${BUILD_MODE} bi ${LIT_BASE_DIR})
+    set(bi "${bi}/${LIT_FILE_NAME}")
     configure_file(
       llvm-lit.in
       ${bi}
@@ -16,6 +17,6 @@ else()
   set(BUILD_MODE .)
   configure_file(
     llvm-lit.in
-    ${llvm_lit_path}
+    ${LIT_BASE_DIR}/${LIT_FILE_NAME}
     )
 endif()
diff --git a/llvm/utils/llvm-lit/llvm-lit.in b/llvm/utils/llvm-lit/llvm-lit.in
index 08a2a670b21..efad97ade7e 100755
--- a/llvm/utils/llvm-lit/llvm-lit.in
+++ b/llvm/utils/llvm-lit/llvm-lit.in
@@ -3,6 +3,15 @@
 import os
 import sys
 
+config_map = {}
+
+def map_config(source_dir, site_config):
+    global config_map
+    source_dir = os.path.normpath(source_dir)
+    source_dir = os.path.normcase(source_dir)
+    site_config = os.path.normpath(site_config)
+    config_map[source_dir] = site_config
+
 # Variables configured at build time.
 llvm_source_root = "@LLVM_SOURCE_DIR@"
 llvm_obj_root = "@LLVM_BINARY_DIR@"
@@ -12,42 +21,11 @@ sys.path.insert(0, os.path.join(llvm_source_root, 'utils', 'lit'))
 
 # Set up some builtin parameters, so that by default the LLVM test suite
 # configuration file knows how to find the object tree.
-builtin_parameters = {
-    'build_mode' : "@BUILD_MODE@",
-    'llvm_site_config' : os.path.join(llvm_obj_root, 'test', 'lit.site.cfg'),
-    'llvm_unit_site_config' : os.path.join(llvm_obj_root, 'test', 'Unit',
-                                           'lit.site.cfg')
-    }
-
-clang_obj_root = os.path.join(llvm_obj_root, 'tools', 'clang')
-
-if os.path.exists(clang_obj_root):
-    builtin_parameters['clang_site_config'] = \
-        os.path.join(clang_obj_root, 'test', 'lit.site.cfg')
-    clang_tools_extra_obj_root = os.path.join(clang_obj_root, 'tools', 'extra')
-    if os.path.exists(clang_tools_extra_obj_root):
-        builtin_parameters['clang_tools_extra_site_config'] = \
-            os.path.join(clang_tools_extra_obj_root, 'test', 'lit.site.cfg')
-
-lld_obj_root = os.path.join(llvm_obj_root, 'tools', 'lld')
-if os.path.exists(lld_obj_root):
-    builtin_parameters['lld_site_config'] = \
-        os.path.join(lld_obj_root, 'test', 'lit.site.cfg')
-
-compilerrt_obj_root = os.path.join(llvm_obj_root, 'projects', 'compiler-rt')
-if os.path.exists(compilerrt_obj_root):
-    builtin_parameters['compilerrt_site_basedir'] = \
-            os.path.join(compilerrt_obj_root, 'test')
-
-libcxx_obj_root = os.path.join(llvm_obj_root, 'projects', 'libcxx')
-if os.path.exists(libcxx_obj_root):
-    builtin_parameters['libcxx_site_config'] = \
-        os.path.join(libcxx_obj_root, 'test', 'lit.site.cfg')
-
-libcxxabi_obj_root = os.path.join(llvm_obj_root, 'projects', 'libcxxabi')
-if os.path.exists(libcxxabi_obj_root):
-    builtin_parameters['libcxxabi_site_config'] = \
-        os.path.join(libcxxabi_obj_root, 'test', 'lit.site.cfg')
+builtin_parameters = { 'build_mode' : "@BUILD_MODE@" }
+
+@LLVM_LIT_CONFIG_MAP@
+
+builtin_parameters['config_map'] = config_map
 
 if __name__=='__main__':
     from lit.main import main
diff --git a/polly/test/Unit/lit.cfg b/polly/test/Unit/lit.cfg
index 9ac67f3acf4..315b70e7581 100644
--- a/polly/test/Unit/lit.cfg
+++ b/polly/test/Unit/lit.cfg
@@ -19,14 +19,11 @@ config.suffixes = []
 
 # test_source_root: The root path where tests are located.
 # test_exec_root: The root path where tests should be run.
-polly_obj_root = getattr(config, 'polly_obj_root', None)
-if polly_obj_root is not None:
-    config.test_exec_root = os.path.join(polly_obj_root, 'unittests')
-    config.test_source_root = config.test_exec_root
+config.test_exec_root = os.path.join(config.polly_obj_root, 'unittests')
+config.test_source_root = config.test_exec_root
 
 # testFormat: The test format to use to interpret tests.
-llvm_build_mode = getattr(config, 'llvm_build_mode', "Debug")
-config.test_format = lit.formats.GoogleTest(llvm_build_mode, 'Tests')
+config.test_format = lit.formats.GoogleTest(config.llvm_build_mode, 'Tests')
 
 # Propagate the temp directory. Windows requires this because it uses \Windows\
 # if none of these are present.
@@ -40,55 +37,6 @@ for symbolizer in ['ASAN_SYMBOLIZER_PATH', 'MSAN_SYMBOLIZER_PATH']:
     if symbolizer in os.environ:
         config.environment[symbolizer] = os.environ[symbolizer]
 
-###
-
-# Check that the object root is known.
-if config.test_exec_root is None:
-    # Otherwise, we haven't loaded the site specific configuration (the user is
-    # probably trying to run on a test file directly, and either the site
-    # configuration hasn't been created by the build system, or we are in an
-    # out-of-tree build situation).
-
-    # Check for 'polly_unit_site_config' user parameter, and use that if available.
-    site_cfg = lit_config.params.get('polly_unit_site_config', None)
-    if site_cfg and os.path.exists(site_cfg):
-        lit_config.load_config(config, site_cfg)
-        raise SystemExit
-
-    # Try to detect the situation where we are using an out-of-tree build by
-    # looking for 'llvm-config'.
-    #
-    # FIXME: I debated (i.e., wrote and threw away) adding logic to
-    # automagically generate the lit.site.cfg if we are in some kind of fresh
-    # build situation. This means knowing how to invoke the build system
-    # though, and I decided it was too much magic.
-
-    llvm_config = lit.util.which('llvm-config', config.environment['PATH'])
-    if not llvm_config:
-        lit_config.fatal('No site specific configuration available!')
-
-    # Get the source and object roots.
-    llvm_src_root = lit.util.capture(['llvm-config', '--src-root']).strip()
-    llvm_obj_root = lit.util.capture(['llvm-config', '--obj-root']).strip()
-    polly_src_root = os.path.join(llvm_src_root, "tools", "polly")
-    polly_obj_root = os.path.join(llvm_obj_root, "tools", "polly")
-
-    # Validate that we got a tree which points to here, using the standard
-    # tools/clang layout.
-    this_src_root = os.path.join(os.path.dirname(__file__),'..','..')
-    if os.path.realpath(polly_src_root) != os.path.realpath(this_src_root):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Check that the site specific configuration exists.
-    site_cfg = os.path.join(polly_obj_root, 'test', 'Unit', 'lit.site.cfg')
-    if not os.path.exists(site_cfg):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Okay, that worked. Notify the user of the automagic, and reconfigure.
-    lit_config.note('using out-of-tree build at %r' % polly_obj_root)
-    lit_config.load_config(config, site_cfg)
-    raise SystemExit
-
 shlibpath_var = ''
 if platform.system() == 'Linux':
     shlibpath_var = 'LD_LIBRARY_PATH'
@@ -98,10 +46,7 @@ elif platform.system() == 'Windows':
     shlibpath_var = 'PATH'
 
 # Point the dynamic loader at dynamic libraries in 'lib'.
-llvm_libs_dir = getattr(config, 'llvm_libs_dir', None)
-if not llvm_libs_dir:
-    lit_config.fatal('No LLVM libs dir set!')
-shlibpath = os.path.pathsep.join((llvm_libs_dir,
+shlibpath = os.path.pathsep.join((config.llvm_libs_dir,
                                  config.environment.get(shlibpath_var,'')))
 
 # Win32 seeks DLLs along %PATH%.
diff --git a/polly/test/lit.cfg b/polly/test/lit.cfg
index ac4eeee52a7..293b4267392 100644
--- a/polly/test/lit.cfg
+++ b/polly/test/lit.cfg
@@ -27,90 +27,25 @@ config.suffixes = ['.ll']
 config.test_source_root = os.path.dirname(__file__)
 
 # test_exec_root: The root path where tests should be run.
-polly_obj_root = getattr(config, 'polly_obj_root', None)
-if polly_obj_root is not None:
-    config.test_exec_root = os.path.join(polly_obj_root, 'test')
-
-# Set llvm_{src,obj}_root for use by others.
-config.llvm_src_root = getattr(config, 'llvm_src_root', None)
-config.llvm_obj_root = getattr(config, 'llvm_obj_root', None)
+config.test_exec_root = os.path.join(config.polly_obj_root, 'test')
 
 # Tweak the PATH to include the tools dir and the scripts dir.
-if polly_obj_root is not None:
-    llvm_tools_dir = getattr(config, 'llvm_tools_dir', None)
-    if not llvm_tools_dir:
-        lit_config.fatal('No LLVM tools dir set!')
-    extra_paths = getattr(config, 'extra_paths', [])
-    base_paths = [llvm_tools_dir, config.environment['PATH']]
-    path = os.path.pathsep.join(base_paths + extra_paths)
-    config.environment['PATH'] = path
-
-    llvm_libs_dir = getattr(config, 'llvm_libs_dir', None)
-    if not llvm_libs_dir:
-        lit_config.fatal('No LLVM libs dir set!')
-    path = os.path.pathsep.join((llvm_libs_dir,
-                                 config.environment.get('LD_LIBRARY_PATH','')))
-    config.environment['LD_LIBRARY_PATH'] = path
-
-###
-
-# Check that the object root is known.
-if config.test_exec_root is None:
-    # Otherwise, we haven't loaded the site specific configuration (the user is
-    # probably trying to run on a test file directly, and either the site
-    # configuration hasn't been created by the build system, or we are in an
-    # out-of-tree build situation).
-
-    # Check for 'polly_site_config' user parameter, and use that if available.
-    site_cfg = lit_config.params.get('polly_site_config', None)
-    if site_cfg and os.path.exists(site_cfg):
-        lit_config.load_config(config, site_cfg)
-        raise SystemExit
-
-    # Try to detect the situation where we are using an out-of-tree build by
-    # looking for 'llvm-config'.
-    #
-    # FIXME: I debated (i.e., wrote and threw away) adding logic to
-    # automagically generate the lit.site.cfg if we are in some kind of fresh
-    # build situation. This means knowing how to invoke the build system though,
-    # and I decided it was too much magic. We should solve this by just having
-    # the .cfg files generated during the configuration step.
-
-    llvm_config = lit.util.which('llvm-config', config.environment['PATH'])
-    if not llvm_config:
-        lit_config.fatal('No site specific configuration available!')
-
-    # Get the source and object roots.
-    llvm_src_root = subprocess.check_output(['llvm-config', '--src-root']).decode("utf-8").strip()
-    llvm_obj_root = subprocess.check_output(['llvm-config', '--obj-root']).decode("utf-8").strip()
-
-    polly_src_root = os.path.join(llvm_src_root, "tools", "polly")
-    polly_obj_root = os.path.join(llvm_obj_root, "tools", "polly")
-
-    # Validate that we got a tree which points to here, using the standard
-    # tools/polly layout.
-    this_src_root = os.path.dirname(config.test_source_root)
-    if os.path.realpath(polly_src_root) != os.path.realpath(this_src_root):
-        lit_config.fatal('No site specific configuration available!')
-
-    # Check that the site specific configuration exists.
-    site_cfg = os.path.join(polly_obj_root, 'test', 'lit.site.cfg')
-    if not os.path.exists(site_cfg):
-        lit_config.fatal('No site specific configuration available!')
+base_paths = [config.llvm_tools_dir, config.environment['PATH']]
+path = os.path.pathsep.join(base_paths + config.extra_paths)
+config.environment['PATH'] = path
 
-    # Okay, that worked. Notify the user of the automagic, and reconfigure.
-    lit_config.note('using out-of-tree build at %r' % polly_obj_root)
-    lit_config.load_config(config, site_cfg)
-    raise SystemExit
+path = os.path.pathsep.join((config.llvm_libs_dir,
+                              config.environment.get('LD_LIBRARY_PATH','')))
+config.environment['LD_LIBRARY_PATH'] = path
 
 # opt knows whether it is compiled with -DNDEBUG.
 import subprocess
 try:
-    opt_cmd = subprocess.Popen([os.path.join(llvm_tools_dir, 'opt'), '-version'],
+    opt_cmd = subprocess.Popen([os.path.join(config.llvm_tools_dir, 'opt'), '-version'],
                            stdout = subprocess.PIPE,
                            env=config.environment)
 except OSError:
-    print("Could not find opt in " + llvm_tools_dir)
+    print("Could not find opt in " + config.llvm_tools_dir)
     exit(42)
 
 if re.search(r'with assertions', opt_cmd.stdout.read().decode('ascii')):
@@ -118,13 +53,14 @@ if re.search(r'with assertions', opt_cmd.stdout.read().decode('ascii')):
 opt_cmd.wait()
 
 try:
-    llvm_config_cmd = subprocess.Popen([os.path.join(llvm_tools_dir,
-                                                     'llvm-config'),
+    llvm_config_cmd = subprocess.Popen([os.path.join(
+                                        config.llvm_tools_dir,
+                                        'llvm-config'),
                                         '--targets-built'],
                                        stdout = subprocess.PIPE,
                                        env=config.environment)
 except OSError:
-    print("Could not find llvm-config in " + llvm_tools_dir)
+    print("Could not find llvm-config in " + config.llvm_tools_dir)
     exit(42)
 
 if re.search(r'NVPTX', llvm_config_cmd.stdout.read().decode('ascii')):