From 70af7aed88456b8c478e06d1d28b0d8523a46b38 Mon Sep 17 00:00:00 2001 From: Ralf Jung Date: Wed, 28 Oct 2020 12:51:25 +0100 Subject: [PATCH] expand flag docs --- README.md | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/README.md b/README.md index 0aa22a81ad..0c280edec0 100644 --- a/README.md +++ b/README.md @@ -240,9 +240,12 @@ environment variable: future use of it will error). This helps you in finding out why UB is happening and where in your code would be a good place to look for it. * `-Zmiri-track-raw-pointers` makes Stacked Borrows track a pointer tag even for - raw pointers. This can make valid code fail to pass the checks (when - integer-pointer casts are involved), but also can help identify latent - aliasing issues in code that Miri accepts by default. + raw pointers. This can make valid code fail to pass the checks, but also can + help identify latent aliasing issues in code that Miri accepts by default. You + can recognize false positives by "" occurring in the message -- this + indicates a pointer that was cast from an integer, so Miri was unable to track + this pointer. Make sure to use a non-Windows target with this flag, as the + Windows runtime makes use of integer-pointer casts. Some native rustc `-Z` flags are also very relevant for Miri: