Rollup merge of #143634 - nia-e:init-and-wildcards, r=RalfJung

interpret/allocation: expose init + write_wildcards on a range

Part of https://github.com/rust-lang/miri/pull/4456, so that we can mark down when a foreign access to our memory happened. Should this also move `prepare_for_native_access()` itself into Miri, given that everything there can be implemented on Miri's side?

r? `````@RalfJung`````

1 files changed, 4 insertions, 3 deletions

diff --git a/src/tools/miri/src/shims/native_lib/mod.rs b/src/tools/miri/src/shims/native_lib/mod.rs
index 9b30d8ce78b..02c3bde036d 100644
--- a/src/tools/miri/src/shims/native_lib/mod.rs
+++ b/src/tools/miri/src/shims/native_lib/mod.rs
@@ -231,7 +231,8 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             .collect::<Vec<libffi::high::Arg<'_>>>();
 
         // Prepare all exposed memory (both previously exposed, and just newly exposed since a
-        // pointer was passed as argument).
+        // pointer was passed as argument). Uninitialised memory is left as-is, but any data
+        // exposed this way is garbage anyway.
         this.visit_reachable_allocs(this.exposed_allocs(), |this, alloc_id, info| {
             // If there is no data behind this pointer, skip this.
             if !matches!(info.kind, AllocKind::LiveData) {
@@ -251,8 +252,8 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
 
             // Prepare for possible write from native code if mutable.
             if info.mutbl.is_mut() {
-                let alloc = &mut this.get_alloc_raw_mut(alloc_id)?.0;
-                alloc.prepare_for_native_access();
+                let (alloc, cx) = this.get_alloc_raw_mut(alloc_id)?;
+                alloc.process_native_write(&cx.tcx, None);
                 // Also expose *mutable* provenance for the interpreter-level allocation.
                 std::hint::black_box(alloc.get_bytes_unchecked_raw_mut().expose_provenance());
             }