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

2 files changed, 17 insertions, 4 deletions

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