Implement the #[sanitize(..)] attribute

This change implements the #[sanitize(..)] attribute, which opts to
replace the currently unstable #[no_sanitize]. Essentially the new
attribute works similar as #[no_sanitize], just with more flexible
options regarding where it is applied. E.g. it is possible to turn
a certain sanitizer either on or off:
`#[sanitize(address = "on|off")]`

This attribute now also applies to more places, e.g. it is possible
to turn off a sanitizer for an entire module or impl block:
```rust
\#[sanitize(address = "off")]
mod foo {
    fn unsanitized(..) {}

    #[sanitize(address = "on")]
    fn sanitized(..) {}
}

\#[sanitize(thread = "off")]
impl MyTrait for () {
    ...
}
```

This attribute is enabled behind the unstable `sanitize` feature.

1 files changed, 11 insertions, 1 deletions

diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index f4d0120a2e7..3bb8353f49e 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -100,7 +100,7 @@ use rustc_session::lint::LintExpectationId;
 use rustc_span::def_id::LOCAL_CRATE;
 use rustc_span::source_map::Spanned;
 use rustc_span::{DUMMY_SP, Span, Symbol};
-use rustc_target::spec::PanicStrategy;
+use rustc_target::spec::{PanicStrategy, SanitizerSet};
 use {rustc_abi as abi, rustc_ast as ast, rustc_hir as hir};
 
 use crate::infer::canonical::{self, Canonical};
@@ -2686,6 +2686,16 @@ rustc_queries! {
         desc { |tcx| "looking up anon const kind of `{}`", tcx.def_path_str(def_id) }
         separate_provide_extern
     }
+
+    /// Checks for the nearest `#[sanitize(xyz = "off")]` or
+    /// `#[sanitize(xyz = "on")]` on this def and any enclosing defs, up to the
+    /// crate root.
+    ///
+    /// Returns the set of sanitizers that is explicitly disabled for this def.
+    query disabled_sanitizers_for(key: LocalDefId) -> SanitizerSet {
+        desc { |tcx| "checking what set of sanitizers are enabled on `{}`", tcx.def_path_str(key) }
+        feedable
+    }
 }
 
 rustc_with_all_queries! { define_callbacks! }