[UTC] Escape multiple {{ or }} in input for check lines.

[fhahn]

SCEV expressions may contain multiple {{ or }} in the debug output, which needs escaping.

See llvm/test/Analysis/LoopAccessAnalysis/loops-with-indirect-reads-and-writes.ll for a test that needs escaping.

[llvmbot]

@llvm/pr-subscribers-llvm-analysis

@llvm/pr-subscribers-testing-tools

Author: Florian Hahn (fhahn)

Changes

SCEV expressions may contain multiple {{ or }} in the debug output, which needs escaping.

See llvm/test/Analysis/LoopAccessAnalysis/loops-with-indirect-reads-and-writes.ll for a test that needs escaping.

---

Full diff: https://github.com/llvm/llvm-project/pull/71790.diff

1 Files Affected:

• (modified) llvm/utils/UpdateTestChecks/common.py (+5)

diff --git a/llvm/utils/UpdateTestChecks/common.py b/llvm/utils/UpdateTestChecks/common.py
index 74044f925aadde4..e8d8d99257e81d0 100644
--- a/llvm/utils/UpdateTestChecks/common.py
+++ b/llvm/utils/UpdateTestChecks/common.py
@@ -1171,6 +1171,7 @@ def transform_line_vars(match):
         return match.group(1) + rv + match.group(match.lastindex)
 
     lines_with_def = []
+    multiple_braces_re = re.compile(r"(({{+)|(}}+))")
 
     for i, line in enumerate(lines):
         if not is_asm and not is_analyze:
@@ -1200,6 +1201,10 @@ def transform_line_vars(match):
                 (lines[i], changed) = nameless_value_regex.subn(
                     transform_line_vars, lines[i], count=1
                 )
+        if is_analyze:
+            # Escape multiple {{ or }} as {{}} denotes a FileCheck regex.
+            scrubbed_line = multiple_braces_re.sub(r"{{\\\1}}", lines[i])
+            lines[i] = scrubbed_line
     return lines
 
 

[nikic]

Can you please add a UTC test for this (or adjust an existing one to exercise this)?

[fhahn]

Can you please add a UTC test for this (or adjust an existing one to exercise this)?

Thanks, added test in 129a91e.

[nikic]

Is this the correct result? Shouldn't this be {{\{\{}}?

[fhahn]

It works for {{, but not for {{{ or more. I updated the code to use a replacement function that escapes each { in the sequence; not sure if there's some python regex magic that does that without a separate function

[github-actions]

⚠️ Python code formatter, darker found issues in your code. ⚠️

You can test this locally with the following command:

darker --check --diff -r 129a91ec01a975e73aaaa9b5010f4085f4ad3cb9..acbd908b61f81cd8bb180f363c167dedf7d0c38d llvm/utils/UpdateTestChecks/common.py

View the diff from darker here.

--- common.py	2023-11-09 17:05:52.000000 +0000
+++ common.py	2023-11-09 17:17:23.933791 +0000
@@ -1170,12 +1170,13 @@
         # including the commas and spaces.
         return match.group(1) + rv + match.group(match.lastindex)
 
     lines_with_def = []
     multiple_braces_re = re.compile(r"({{+)|(}}+)")
+
     def escape_braces(match_obj):
-        return '{{' + re.escape(match_obj.group(0)) + '}}'
+        return "{{" + re.escape(match_obj.group(0)) + "}}"
 
     for i, line in enumerate(lines):
         if not is_asm and not is_analyze:
             # An IR variable named '%.' matches the FileCheck regex string.
             line = line.replace("%.", "%dot")

[nikic]

Suggested change

	s = match_obj.group(0)
	escaped = ''
	if s[0] == '{':
	escaped = s.replace('{', '\\{')
	else:
	escaped = s.replace('}', '\\}')
	return ''.join(['{{', escaped, '}}'])
	return re.escape(match_obj.group(0))

I think something like this would work? As we are actually escaping for use in a regex, the use of re.escape seems appropriate.

[fhahn]

That works well, we just need to manually add the wrapping {{ / }}

[nikic]

LGTM