[Flang] test_symbols.py module file fix

[ijan1]

Summary

Due to how the LIT deals with module files,
this change stores and runs the scripts in
their own temporary directory to prevent
interference in-between different tests.
It also makes `test_symbols.py` be more
consistent with the other scripts.

[awarzynski]

Males sense, thank you for working on this! I've made a couple of small suggestions.

flang/test/Semantics/test_symbols.py

5–11

I'm suggesting a small edit to make it clearer what the input arguments to this script are.

22

I'm suggesting a bit more descriptive variable here. tmp could mean a temporary file, directory, socket etc.

[Meinersbur]

Is there a reason to use lit's suggestion for a temporary directory instead using tempfile.TemporaryDirectory or tempfile.mkdtemp?

flang/test/Semantics/test_symbols.py

44–45

[ijan1]

In D107953#2941417, @Meinersbur wrote:

Is there a reason to use lit's suggestion for a temporary directory instead using tempfile.TemporaryDirectory or tempfile.mkdtemp?

I decided to use what's already in the LIT and it also more accurately reflects the behaviour of the bash script. Besides that, I don't see a reason why I couldn't use the tempfile library.

[awarzynski]

In D107953#2941417, @Meinersbur wrote:

Is there a reason to use lit's suggestion for a temporary directory instead using tempfile.TemporaryDirectory or tempfile.mkdtemp?

I like this suggestion - with tempfile.TemporaryDirectory the tests wouldn't require the extra argument (%t). Is the temporary directory name guaranteed to be unique to every test? That wasn't 100% obvious to me from the docs.

[Meinersbur]

In D107953#2942187, @awarzynski wrote:

Is the temporary directory name guaranteed to be unique to every test? That wasn't 100% obvious to me from the docs.

%t expands to <builddir>/tools/flang/test/<filename>.tmp. That is, it is unique for every test file, but that same for multiple RUN lines in the file and between make check invocations. However, I think it is better to always have a fresh temporary directory, flang-new does not need to see the leftover files from the previous make check run, those should be independent.

[awarzynski]

In D107953#2944145, @Meinersbur wrote:

%t expands to <builddir>/tools/flang/test/<filename>.tmp. That is, it is unique for every test file, but that same for multiple RUN lines in the file and between make check invocations. However, I think it is better to always have a fresh temporary directory, flang-new does not need to see the leftover files from the previous make check run, those should be independent.

+1 for this approach, thank you for the suggestion!

[ijan1]

Updated to use tempfile.TemporaryDirectory. Addressed comments by Andrzej.

[Meinersbur]

LGTM

flang/test/Semantics/test_symbols.py

 #!/usr/bin/env python3
 
 """Compiles a source file with "-fdebug-unparse-with-symbols' and verifies
 we get the right symbols in the output, i.e. the output should be
 the same as the input, except for the copyright comment.
-Expects a source file passed as the first argument;
-Expects the Flang frontend driver with options as second argument."""
+
+Parameters:
+    sys.argv[1]: a source file with contains the input and expected output
+    sys.argv[2]: the Flang frontend driver
+    sys.argv[3:]: Optional arguments to the Flang frontend driver"""
 
 import sys
+import tempfile
 import re
 import subprocess
 import common as cm
 
 from difflib import unified_diff
 
 cm.check_args(sys.argv)
 src = cm.set_source(sys.argv[1])
 diff1 = ""
 diff2 = ""
 
 flang_fc1 = cm.set_executable(sys.argv[2])
 flang_fc1_args = sys.argv[3:]
 flang_fc1_options = "-fdebug-unparse-with-symbols"
 
 # Strips out blank lines and all comments except for "!DEF:", "!REF:", "!$acc" and "!$omp"
 with open(src, 'r') as text_in:
     for line in text_in:
         text = re.sub(r"!(?![DR]EF:|\$omp|\$acc).*", "", line)
         text = re.sub(r"^\s*$", "", text)
         diff1 += text
 
 # Strips out "!DEF:" and "!REF:" comments
 for line in diff1:
     text = re.sub(r"![DR]EF:.*", "", line)
     diff2 += text
 
 # Compiles, inserting comments for symbols:
 cmd = [flang_fc1, *flang_fc1_args, flang_fc1_options]
-diff3 = subprocess.check_output(cmd, input=diff2, universal_newlines=True)
+with tempfile.TemporaryDirectory() as tmpdir:
+    diff3 = subprocess.check_output(cmd, input=diff2, universal_newlines=True, cwd=tmpdir)
 
 # Removes all whitespace to compare differences in files
 diff1 = diff1.replace(" ", "")
 diff3 = diff3.replace(" ", "")
 diff_check = ""
 
 # Compares the input with the output
 diff_check = "\n".join(unified_diff(diff1.split("\n"), diff3.split("\n"), n=999999,
                        fromfile="Expected_output", tofile="Actual_output"))