tint: add parse_hlsl_errors.py to help triage hlsl errors

Change-Id: If160a8c72c407874060024c365faca83722b541f
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/103760
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>

test/tint/parse_hlsl_errors.py

@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+
+# Copyright 2021 The Tint Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Parses expected.*.hlsl files for errors and outputs a report.
+#
+# Usage:
+#    parse_hlsl_erors
+
+import glob
+import re
+import argparse
+
+parser = argparse.ArgumentParser()
+parser.add_argument('--list-files', dest='list_files', action='store_true')
+parser.add_argument('--no-list-files', dest='list_files', action='store_false')
+parser.set_defaults(list_files=True)
+args = parser.parse_args()
+
+def add_error(error_to_file, error, file):
+    if not error in error_to_file:
+        error_to_file[error] = [file]
+    else:
+        error_to_file[error].append(file)
+
+def find_and_print_errors(glob_pathname):
+    files = glob.glob(glob_pathname, recursive=True)
+    error_to_file = {}
+
+    for f in files:
+        found_error = False
+        with open(f, "r") as fs:
+            first_line = fs.readline()
+            if not first_line.startswith("SKIP:"):
+                continue
+            for line in fs:
+                m = re.search('error( X[0-9]+)*?:(.*)', line)
+                if m:
+                    add_error(error_to_file, m.group(), f)
+                    found_error = True
+                else:
+                    if "exit status" in line:
+                        add_error(error_to_file, line, f)
+                        found_error = True
+                if found_error:
+                    break # Stop on first error string found
+
+        if not found_error:
+            # If no error message was found, add the SKIP line as it may contain the reason for skipping
+            add_error(error_to_file, first_line.strip(), f)
+
+    for error,files in sorted(error_to_file.items()):
+        print('{} (count: {})'.format(error, len(files)))
+        if args.list_files:
+            for f in files:
+                print('\t{}'.format(f))
+
+print("=== FXC ===")
+find_and_print_errors('./**/*.fxc.hlsl')
+
+print("=== DXC ===")
+find_and_print_errors('./**/*.dxc.hlsl')