Auto merge of #1748 - jrvanwhy:track-raw-pointers-doc, r=RalfJung

Improvements to the README item on `-Zmiri-track-raw-pointers`.

[Rendered](https://github.com/jrvanwhy/miri/tree/track-raw-pointers-doc)

Minor change: I changed the quotes around `<untagged>` into backticks, so they render correctly in markdown.

~~Significant change: I documented that `-Zmiri-track-raw-pointers` is a strictly more restrictive model that "normal" Stacked Borrows. **I am not confident this change is correct, please verify it.** If this change is not correct, let me know, and I'll update this PR to document that :-)~~

EDIT: I was wrong, `-Zmiri-track-raw-pointers` may not be strictly more restrictive. I added the following sentence to prevent others from making the same assumption that I did:

> Note that it is not currently guaranteed that code that works with `-Zmiri-track-raw-pointers` also works without `-Zmiri-track-raw-pointers`.
This commit is contained in:
bors 2021-03-25 08:27:25 +00:00
commit 91aeb04408

View File

@ -252,9 +252,11 @@ environment variable:
* `-Zmiri-track-raw-pointers` makes Stacked Borrows track a pointer tag even for * `-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, but also can 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 help identify latent aliasing issues in code that Miri accepts by default. You
can recognize false positives by "<untagged>" occurring in the message -- this can recognize false positives by `<untagged>` occurring in the message -- this
indicates a pointer that was cast from an integer, so Miri was unable to track indicates a pointer that was cast from an integer, so Miri was unable to track
this pointer. this pointer. Note that it is not currently guaranteed that code that works
with `-Zmiri-track-raw-pointers` also works without
`-Zmiri-track-raw-pointers`, but for the vast majority of code, this will be the case.
Some native rustc `-Z` flags are also very relevant for Miri: Some native rustc `-Z` flags are also very relevant for Miri: