code review commits (use rustc_data_structures::fx::FxHashSet, prepare_for_native_write, document write_wildcards

Author: Strophox

compiler/rustc_const_eval/src/interpret/memory.rs

@@ -952,7 +952,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         // Expose provenance of the root allocation.
         M::expose_provenance(self, initial_prov)?;
 
-        let mut done = rustc_data_structures::fx::FxHashSet::default();
+        let mut done = FxHashSet::default();
         let mut todo = vec![id];
         while let Some(id) = todo.pop() {
             if !done.insert(id) {
@@ -979,7 +979,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             if info.mutbl.is_mut() {
                 self.get_alloc_raw_mut(id)?
                     .0
-                    .prepare_for_native_call()
+                    .prepare_for_native_write()
                     .map_err(|e| e.to_interp_error(id))?;
             }
         }

compiler/rustc_middle/src/mir/interpret/allocation.rs

@@ -646,7 +646,7 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
     /// Initialize all previously uninitialized bytes in the entire allocation, and set
     /// provenance of everything to `Wildcard`. Before calling this, make sure all
     /// provenance in this allocation is exposed!
-    pub fn prepare_for_native_call(&mut self) -> AllocResult {
+    pub fn prepare_for_native_write(&mut self) -> AllocResult {
         let full_range = AllocRange { start: Size::ZERO, size: Size::from_bytes(self.len()) };
         // Overwrite uninitialized bytes with 0, to ensure we don't leak whatever their value happens to be.
         for chunk in self.init_mask.range_as_init_chunks(full_range) {

compiler/rustc_middle/src/mir/interpret/allocation/provenance_map.rs

@@ -195,8 +195,11 @@ impl<Prov: Provenance> ProvenanceMap<Prov> {
 
         Ok(())
     }
+
+    /// Overwrites all provenance in the allocation with wildcard provenance.
+    ///
+    /// Provided for usage in Miri and panics otherwise.
     pub fn write_wildcards(&mut self, alloc_size: usize) {
-        // We can only write wildcards in Miri.
         assert!(
             Prov::OFFSET_IS_ADDR,
             "writing wildcard provenance is not supported when `OFFSET_IS_ADDR` is false"

src/tools/miri/tests/native-lib/ptr_write_access.c

@@ -51,4 +51,4 @@ EXPORT void overwrite_ptr(const int **pptr) {
 
 EXPORT void blackbox(__attribute__((unused)) const int ***_ppptr) {
   return;
-}
+}