[llvm] Avoid a race condition in opt-viewer/optrecord (PR #131214)
Miro HronĨok via llvm-commits
llvm-commits at lists.llvm.org
Thu Mar 13 13:57:58 PDT 2025
https://github.com/hroncok updated https://github.com/llvm/llvm-project/pull/131214
>From 7086b50d632ad60d6335e3752accd00ae43ce847 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miro=20Hron=C4=8Dok?= <miro at hroncok.cz>
Date: Thu, 13 Mar 2025 21:53:05 +0100
Subject: [PATCH] Avoid a race condition in opt-viewer/optrecord
See https://bugzilla.redhat.com/2336915
See https://reviews.llvm.org/D41784?id=
See https://github.com/androm3da/optviewer-demo/issues/4#issuecomment-718787822
Fixes https://github.com/llvm/llvm-project/issues/62403
The race condition happened when the demangler_proc was being set.
The locking mechanism itself happened too late.
This way, the lock always exists (to avoid a race when creating it)
and is always used when *creating* demangler_proc.
I don't have any prior experience with the codebase
and I cannot guarantee the behavior is correct.
It appears to get rid of the race (which I was seeing consistently).
multiprocessing.pool.RemoteTraceback:
"""
Traceback (most recent call last):
File "/usr/lib64/python3.14/multiprocessing/pool.py", line 125, in worker
result = (True, func(*args, **kwds))
~~~~^^^^^^^^^^^^^^^
File "/usr/lib64/python3.14/multiprocessing/pool.py", line 48, in mapstar
return list(map(*args))
File "/builddir/build/BUILD/llvm-19.1.6-build/llvm-project-19.1.6.src/llvm/tools/opt-viewer/optpmap.py", line 25, in _wrapped_func
return func(argument, filter_)
File "/builddir/build/BUILD/llvm-19.1.6-build/llvm-project-19.1.6.src/llvm/tools/opt-viewer/opt-viewer.py", line 293, in _render_file
SourceFileRenderer(source_dir, output_dir, filename, no_highlight).render(remarks)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
File "/builddir/build/BUILD/llvm-19.1.6-build/llvm-project-19.1.6.src/llvm/tools/opt-viewer/opt-viewer.py", line 216, in render
self.render_source_lines(self.source_stream, line_remarks)
~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/builddir/build/BUILD/llvm-19.1.6-build/llvm-project-19.1.6.src/llvm/tools/opt-viewer/opt-viewer.py", line 123, in render_source_lines
self.render_inline_remarks(remark, html_line)
~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
File "/builddir/build/BUILD/llvm-19.1.6-build/llvm-project-19.1.6.src/llvm/tools/opt-viewer/opt-viewer.py", line 126, in render_inline_remarks
inlining_context = r.DemangledFunctionName
^^^^^^^^^^^^^^^^^^^^^^^
File "/builddir/build/BUILD/llvm-19.1.6-build/llvm-project-19.1.6.src/llvm/tools/opt-viewer/optrecord.py", line 153, in DemangledFunctionName
return self.demangle(self.Function)
~~~~~~~~~~~~~^^^^^^^^^^^^^^^
File "/builddir/build/BUILD/llvm-19.1.6-build/llvm-project-19.1.6.src/llvm/tools/opt-viewer/optrecord.py", line 77, in demangle
with cls.demangler_lock:
^^^^^^^^^^^^^^^^^^
AttributeError: type object 'Passed' has no attribute 'demangler_lock'. Did you mean: 'demangler_proc'?
"""
---
llvm/tools/opt-viewer/optrecord.py | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/llvm/tools/opt-viewer/optrecord.py b/llvm/tools/opt-viewer/optrecord.py
index 9e2fc7cb553b5..8014204a64f45 100644
--- a/llvm/tools/opt-viewer/optrecord.py
+++ b/llvm/tools/opt-viewer/optrecord.py
@@ -64,17 +64,19 @@ class Remark(yaml.YAMLObject):
default_demangler = "c++filt -n"
demangler_proc = None
+ demangler_lock = Lock()
@classmethod
def set_demangler(cls, demangler):
cls.demangler_proc = subprocess.Popen(
demangler.split(), stdin=subprocess.PIPE, stdout=subprocess.PIPE
)
- cls.demangler_lock = Lock()
@classmethod
def demangle(cls, name):
with cls.demangler_lock:
+ if not cls.demangler_proc:
+ cls.set_demangler(cls.default_demangler)
cls.demangler_proc.stdin.write((name + "\n").encode("utf-8"))
cls.demangler_proc.stdin.flush()
return cls.demangler_proc.stdout.readline().rstrip().decode("utf-8")
@@ -323,8 +325,6 @@ def get_remarks(input_file, filter_=None):
def gather_results(filenames, num_jobs, should_print_progress, filter_=None):
if should_print_progress:
print("Reading YAML files...")
- if not Remark.demangler_proc:
- Remark.set_demangler(Remark.default_demangler)
remarks = optpmap.pmap(
get_remarks, filenames, num_jobs, should_print_progress, filter_
)
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