[PATCH] D54469: Introduce new `disable_init` ASan option that is only supported on platforms where `SANITIZER_SUPPORTS_DISABLED_INIT` is true. Currently this is only supported on Darwin.

[Kuba (Brecka) Mracek via Phabricator via llvm-commits]

kubamracek added inline comments.


================
Comment at: lib/sanitizer_common/sanitizer_platform.h:348-352
+#if SANITIZER_MAC
+#define SANITIZER_SUPPORTS_INIT_FOR_DLOPEN 1
+#else
+#define SANITIZER_SUPPORTS_INIT_FOR_DLOPEN 0
+#endif
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delcypher wrote:
> kubamracek wrote:
> > Why do we need this? I'd remove it.
> Two reasons:
> 
> 1. I wanted the feature to be zero-cost for platforms that don't use it. You can see it's used in the `if` condition in `AsanInitInternal()`. It's a compile time constant so for platforms that don't support this feature the branch should just be folded away and so it won't even be checked at runtime.
> 2. We need to something to let us switch between the definitions of  `InitIsViaDlopen()` and ` HandleDlopenInit()`. This macro is used for this.
> 
> If you have a clean solution to handle the second reason without `SANITIZER_SUPPORTS_INIT_FOR_DLOPEN` then I can implement it.
We're trying to minimize compile-time constants, as that adds complexity. Why not just have this behavior (reading an env var to skip initialization) on all platforms?


Repository:
  rCRT Compiler Runtime

https://reviews.llvm.org/D54469