Factor out the cache-related parts of Stack

Author: saethlin

src/lib.rs

@@ -86,8 +86,8 @@ pub use crate::mono_hash_map::MonoHashMap;
 pub use crate::operator::EvalContextExt as OperatorEvalContextExt;
 pub use crate::range_map::RangeMap;
 pub use crate::stacked_borrows::{
-    CallId, EvalContextExt as StackedBorEvalContextExt, Item, Permission, PtrId, SbTag, Stack,
-    Stacks,
+    stack::Stack, CallId, EvalContextExt as StackedBorEvalContextExt, Item, Permission, PtrId,
+    SbTag, Stacks,
 };
 pub use crate::sync::{CondvarId, EvalContextExt as SyncEvalContextExt, MutexId, RwLockId};
 pub use crate::thread::{

src/machine.rs

@@ -25,7 +25,7 @@ use rustc_middle::{
     },
 };
 use rustc_span::def_id::{CrateNum, DefId};
-use rustc_span::Symbol;
+use rustc_span::{Span, Symbol};
 use rustc_target::abi::Size;
 use rustc_target::spec::abi::Abi;
 
@@ -415,6 +415,10 @@ impl<'mir, 'tcx> Evaluator<'mir, 'tcx> {
         let def_id = frame.instance.def_id();
         def_id.is_local() || self.local_crates.contains(&def_id.krate)
     }
+
+    pub(crate) fn current_span(&self) -> CurrentSpan<'_, 'mir, 'tcx> {
+        CurrentSpan { span: None, machine: self }
+    }
 }
 
 /// A rustc InterpCx for Miri.
@@ -580,8 +584,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
                 alloc.size(),
                 stacked_borrows,
                 kind,
-                &ecx.machine.threads,
-                ecx.machine.local_crates.clone(),
+                ecx.machine.current_span(),
             ))
         } else {
             None
@@ -663,7 +666,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
                 tag,
                 range,
                 machine.stacked_borrows.as_ref().unwrap(),
-                &machine.threads,
+                machine.current_span(),
             )
         } else {
             Ok(())
@@ -687,7 +690,7 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
                 tag,
                 range,
                 machine.stacked_borrows.as_ref().unwrap(),
-                &machine.threads,
+                machine.current_span(),
             )
         } else {
             Ok(())
@@ -789,3 +792,33 @@ impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
         res
     }
 }
+
+#[derive(Clone)]
+pub struct CurrentSpan<'a, 'tcx, 'mir> {
+    span: Option<Span>,
+    machine: &'a Evaluator<'tcx, 'mir>,
+}
+
+impl<'a, 'tcx, 'mir> CurrentSpan<'a, 'tcx, 'mir> {
+    pub fn get(&mut self) -> rustc_span::Span {
+        if self.span.is_none() {
+            self.span = Some(self.current_span());
+        }
+        self.span.unwrap()
+    }
+
+    #[inline(never)]
+    fn current_span(&self) -> Span {
+        self.machine
+            .threads
+            .active_thread_stack()
+            .into_iter()
+            .rev()
+            .find(|frame| {
+                let def_id = frame.instance.def_id();
+                def_id.is_local() || self.machine.local_crates.contains(&def_id.krate)
+            })
+            .map(|frame| frame.current_span())
+            .unwrap_or(rustc_span::DUMMY_SP)
+    }
+}