[libc++] Stop using awk in transitive includes test

For some reason, that doesn't work as expected on Github-hosted
runners and in Docker-in-Docker setups.

Author: ldionne

libcxx/test/libcxx/transitive_includes.gen.py

@@ -55,7 +55,7 @@
 
     print(
         f"""\
-// RUN: %{{python}} %{{libcxx-dir}}/test/libcxx/transitive_includes_to_csv.py {' '.join(all_traces)} > %{{libcxx-dir}}/test/libcxx/transitive_includes/%{{cxx_std}}.csv
+// RUN: %{{python}} %{{libcxx-dir}}/test/libcxx/transitive_includes/to_csv.py {' '.join(all_traces)} > %{{libcxx-dir}}/test/libcxx/transitive_includes/%{{cxx_std}}.csv
 """
     )
 
@@ -64,9 +64,6 @@
         if header.endswith(".h"):  # Skip C compatibility or detail headers
             continue
 
-        # Escape slashes for the awk command below
-        escaped_header = header.replace("/", "\\/")
-
         print(
             f"""\
 //--- {header}.sh.cpp
@@ -92,9 +89,9 @@
 
 // RUN: mkdir %t
 // RUN: %{{cxx}} %s %{{flags}} %{{compile_flags}} --trace-includes -fshow-skipped-includes --preprocess > /dev/null 2> %t/trace-includes.txt
-// RUN: %{{python}} %{{libcxx-dir}}/test/libcxx/transitive_includes_to_csv.py %t/trace-includes.txt > %t/actual_transitive_includes.csv
-// RUN: cat %{{libcxx-dir}}/test/libcxx/transitive_includes/%{{cxx_std}}.csv | awk '/^{escaped_header} / {{ print }}' > %t/expected_transitive_includes.csv
-// RUN: diff -w %t/expected_transitive_includes.csv %t/actual_transitive_includes.csv
+// RUN: %{{python}} %{{libcxx-dir}}/test/libcxx/transitive_includes/to_csv.py %t/trace-includes.txt > %t/actual_transitive_includes.csv
+// RUN: %{{python}} %{{libcxx-dir}}/test/libcxx/transitive_includes/expected.py %{{cxx_std}} "{header}" > %t/expected_transitive_includes.csv
+// RUN: %{{python}} %{{libcxx-dir}}/test/libcxx/transitive_includes/diff.py %t/expected_transitive_includes.csv %t/actual_transitive_includes.csv
 #include <{header}>
 """
         )

libcxx/test/libcxx/transitive_includes/diff.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python
+# ===----------------------------------------------------------------------===##
+#
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# ===----------------------------------------------------------------------===##
+
+import argparse
+import os
+import sys
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="""Diff two files.""",
+    )
+    parser.add_argument("file1", default=None)
+    parser.add_argument("file2", default=None)
+    args = parser.parse_args()
+
+    def doread(f):
+        with open(f, 'r') as file:
+            content = file.read()
+        lines = [l.strip() for l in content.splitlines()]
+        return list(filter(None, lines))
+
+    content1 = doread(args.file1)
+    content2 = doread(args.file2)
+
+    for l1, l2 in zip(content1, content2):
+        if l1 != l2:
+            print("line not equal")
+            print(l1)
+            print(l2)
+            sys.exit(1)

libcxx/test/libcxx/transitive_includes/expected.py

@@ -0,0 +1,35 @@
+#!/usr/bin/env python
+# ===----------------------------------------------------------------------===##
+#
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# ===----------------------------------------------------------------------===##
+
+import argparse
+import os
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="""Extract the list of expected transitive includes for the given Standard and header.""",
+    )
+    parser.add_argument(
+        "standard",
+        default=None,
+        choices=["cxx03", "cxx11", "cxx14", "cxx20", "cxx23", "cxx26"],
+    )
+    parser.add_argument(
+        "header",
+        default=None,
+        help="The header to extract the expected transitive includes for."
+    )
+    args = parser.parse_args()
+
+    CSV_ROOT = os.path.dirname(__file__)
+    filename = os.path.join(CSV_ROOT, f"{args.standard}.csv")
+    with open(filename, 'r') as f:
+        for line in f.readlines():
+            if line.startswith(args.header + ' '):
+                print(line, end='') # lines already end in newline