[PATCH] D106206: Lazy initialized the NotUnderValgrind flag

[Duncan P. N. Exon Smith via Phabricator via llvm-commits]

dexonsmith added inline comments.


================
Comment at: llvm/lib/Support/Valgrind.cpp:27-38
+namespace {
+struct CreateNotUnderValgrind {
+  static void *call() { return new bool{!RUNNING_ON_VALGRIND}; }
+};
+} // namespace
+static const llvm::ManagedStatic<bool, CreateNotUnderValgrind> NotUnderValgrind;
 
----------------
dexonsmith wrote:
> Can `NotUnderValgrind` be merged into `RunningOnValgrind`, skipping the managed static?
> 
> The only reason not to is if it `RUNNING_ON_VALGRIND` could return "true" on the first use, but "false" some time later in the same execution. I don't imagine that's possible...?
> 
> ... but if it //is// possible, maybe switching to ManagedStatic isn't safe either, since there would be a reason to cache the value at load-time instead of at first use.
(Based on https://www.valgrind.org/docs/manual/manual-core-adv.html I strongly doubt load-time is special in any way...)


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D106206/new/

https://reviews.llvm.org/D106206