[PATCH] D108029: [clang][Codegen] Introduce the no_sanitizer_instrumentation attribute

[Alexander Potapenko via Phabricator via llvm-commits]

glider added inline comments.


================
Comment at: clang/include/clang/Basic/AttrDocs.td:2601-2602
+
+This is not the same as ``__attribute__((no_sanitize(...)))``, which depending
+on the tool may still insert instrumentation to prevent false positive reports.
+  }];
----------------
aaron.ballman wrote:
> Has there been agreement that this isn't actually a bug? My understanding of `no_sanitize` is that it disables sanitizer support for a function or global. The documentation for that attribute says:
> ```
> Use the ``no_sanitize`` attribute on a function or a global variable
> declaration to specify that a particular instrumentation or set of
> instrumentations should not be applied.
> ```
> That sure reads like "do not instrument this at all" to me, and makes me think we don't need a second attribute that says "no, really, I mean it this time."
No, this isn't a bug, but might need to be better clarified in the docs.
ThreadSanitizer and MemorySanitizer do insert some instrumentation into ignore functions to prevent false positives:

> ThreadSanitizer still instruments such functions to avoid false positives and provide meaningful stack traces.

(https://clang.llvm.org/docs/ThreadSanitizer.html#attribute-no-sanitize-thread)

and 

> MemorySanitizer may still instrument such functions to avoid false positives.

(https://clang.llvm.org/docs/MemorySanitizer.html#attribute-no-sanitize-memory)

This is the behavior people rely onto, although at this point I don't think `no_sanitize(...)` is the best name for attribute not disabling instrumentation completely.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D108029/new/

https://reviews.llvm.org/D108029