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

This patch is still breaking several multi-stage compiler-rt bots.
I already know what the fix is, but I want to get the bots green
for now and then try re-applying in the morning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313335 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 52 insertions, 3 deletions

diff --git a/test/Unit/lit.cfg b/test/Unit/lit.cfg
index 609408d1dd8..9da82f5f2c9 100644
--- a/test/Unit/lit.cfg
+++ b/test/Unit/lit.cfg
@@ -18,11 +18,14 @@ 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.
-config.test_exec_root = os.path.join(config.llvm_obj_root, 'unittests')
-config.test_source_root = config.test_exec_root
+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
 
 # testFormat: The test format to use to interpret tests.
-config.test_format = lit.formats.GoogleTest(config.llvm_build_mode, 'Tests')
+llvm_build_mode = getattr(config, 'llvm_build_mode', "Debug")
+config.test_format = lit.formats.GoogleTest(llvm_build_mode, 'Tests')
 
 # Propagate the temp directory. Windows requires this because it uses \Windows\
 # if none of these are present.
@@ -44,3 +47,49 @@ 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