This is an archive of the discontinued LLVM Phabricator instance.

Differential D124058

[msan] Update Use-after-destruction documentation
ClosedPublic

Authored by vitalybuka on Apr 19 2022, 6:42 PM.

Details

Reviewers
kda
eugenis
Commits
rGb580c0e01982: [msan] Update Use-after-destruction documentation

Diff Detail

Event Timeline

vitalybuka created this revision.Apr 19 2022, 6:42 PM
Herald added a project: Restricted Project. · View Herald TranscriptApr 19 2022, 6:42 PM
vitalybuka requested review of this revision.Apr 19 2022, 6:42 PM
Herald added a project: Restricted Project. · View Herald TranscriptApr 19 2022, 6:42 PM
Herald added a subscriber: cfe-commits. · View Herald Transcript
vitalybuka added reviewers: kda, eugenis.Apr 19 2022, 6:43 PM
Harbormaster completed remote builds in B160357: Diff 423783.Apr 19 2022, 7:28 PM
kda accepted this revision.Apr 20 2022, 2:26 PM
This revision is now accepted and ready to land.Apr 20 2022, 2:26 PM
eugenis accepted this revision.Apr 20 2022, 3:15 PM
Closed by commit rGb580c0e01982: [msan] Update Use-after-destruction documentation (authored by vitalybuka). · Explain WhyApr 21 2022, 2:02 PM
This revision was automatically updated to reflect the committed changes.
vitalybuka added a commit: rGb580c0e01982: [msan] Update Use-after-destruction documentation.

Revision Contents

PathSize
clang/
docs/
15 lines

Diff 424284

clang/docs/MemorySanitizer.rst

Show First 20 Lines • Show All 156 Lines • ▼ Show 20 Lines
Clang option ``-fsanitize-memory-track-origins=1`` enables a slightly Clang option ``-fsanitize-memory-track-origins=1`` enables a slightly
faster mode when MemorySanitizer collects only allocation points but faster mode when MemorySanitizer collects only allocation points but
not intermediate stores. not intermediate stores.
Use-after-destruction detection Use-after-destruction detection
=============================== ===============================
You can enable experimental use-after-destruction detection in MemorySanitizer. MemorySanitizer includes use-after-destruction detection. After invocation of
After invocation of the destructor, the object will be considered no longer the destructor, the object will be considered no longer readable, and using
readable, and using underlying memory will lead to error reports in runtime. underlying memory will lead to error reports in runtime. Refer to the standard
Refer to the standard for `lifetime <https://eel.is/c++draft/basic.life#1>`_ definition. for `lifetime <https://eel.is/c++draft/basic.life#1>`_ definition.
This feature is still experimental, in order to enable it at runtime you need This feature can be disabled with either:
to:
#. Pass addition Clang option ``-fsanitize-memory-use-after-dtor`` during #. Pass addition Clang option ``-fno-sanitize-memory-use-after-dtor`` during
compilation. compilation.
#. Set environment variable `MSAN_OPTIONS=poison_in_dtor=1` before running #. Set environment variable `MSAN_OPTIONS=poison_in_dtor=0` before running
the program. the program.
Handling external code Handling external code
====================== ======================
MemorySanitizer requires that all program code is instrumented. This MemorySanitizer requires that all program code is instrumented. This
also includes any libraries that the program depends on, even libc. also includes any libraries that the program depends on, even libc.
Failing to achieve this may result in false reports. Failing to achieve this may result in false reports.
▲ Show 20 Lines • Show All 48 Lines • Show Last 20 Lines