[lit] Modify LIT to accept environment variable LIT_FILTER to select tests.

This is especially useful when lit is invoked indirectly by the build
system, and additional arguments can not be easily specified.

Differential Revision: https://reviews.llvm.org/D35091

llvm-svn: 307339

2 files changed, 7 insertions, 1 deletions

diff --git a/llvm/utils/lit/lit/main.py b/llvm/utils/lit/lit/main.py
index a7f407fc210..530f962d336 100755
--- a/llvm/utils/lit/lit/main.py
+++ b/llvm/utils/lit/lit/main.py
@@ -262,7 +262,8 @@ def main_with_tmp(builtinParameters):
     selection_group.add_argument("--filter", metavar="REGEX",
                      help=("Only run tests with paths matching the given "
                            "regular expression"),
-                     action="store", default=None)
+                     action="store",
+                     default=os.environ.get("LIT_FILTER"))
     selection_group.add_argument("--num-shards", dest="numShards", metavar="M",
                      help="Split testsuite into M pieces and only run one",
                      action="store", type=int,
diff --git a/llvm/utils/lit/tests/selecting.py b/llvm/utils/lit/tests/selecting.py
index 72d6fbabdc9..19ba240f9b0 100644
--- a/llvm/utils/lit/tests/selecting.py
+++ b/llvm/utils/lit/tests/selecting.py
@@ -7,6 +7,11 @@
 # RUN: %{lit} --filter 'o[a-z]e' %{inputs}/discovery | FileCheck --check-prefix=CHECK-FILTER %s
 # CHECK-FILTER: Testing: 2 of 5 tests
 
+# Check that regex-filtering based on environment variables work.
+#
+# RUN: LIT_FILTER='o[a-z]e' %{lit} %{inputs}/discovery | FileCheck --check-prefix=CHECK-FILTER-ENV %s
+# CHECK-FILTER-ENV: Testing: 2 of 5 tests
+
 
 # Check that maximum counts work
 #