2 files changed, 20 insertions, 8 deletions
diff --git a/compiler/rustc_data_structures/src/memmap.rs b/compiler/rustc_data_structures/src/memmap.rs
index c7f66b2fee8..d64a5862f4e 100644
--- a/compiler/rustc_data_structures/src/memmap.rs
+++ b/compiler/rustc_data_structures/src/memmap.rs
@@ -3,13 +3,13 @@ use std::io;
 use std::ops::{Deref, DerefMut};
 
 /// A trivial wrapper for [`memmap2::Mmap`] (or `Vec<u8>` on WASM).
-#[cfg(not(target_arch = "wasm32"))]
+#[cfg(not(any(miri, target_arch = "wasm32")))]
 pub struct Mmap(memmap2::Mmap);
 
-#[cfg(target_arch = "wasm32")]
+#[cfg(any(miri, target_arch = "wasm32"))]
 pub struct Mmap(Vec<u8>);
 
-#[cfg(not(target_arch = "wasm32"))]
+#[cfg(not(any(miri, target_arch = "wasm32")))]
 impl Mmap {
     /// # Safety
     ///
@@ -29,7 +29,7 @@ impl Mmap {
     }
 }
 
-#[cfg(target_arch = "wasm32")]
+#[cfg(any(miri, target_arch = "wasm32"))]
 impl Mmap {
     #[inline]
     pub unsafe fn map(mut file: File) -> io::Result<Self> {
@@ -56,13 +56,13 @@ impl AsRef<[u8]> for Mmap {
     }
 }
 
-#[cfg(not(target_arch = "wasm32"))]
+#[cfg(not(any(miri, target_arch = "wasm32")))]
 pub struct MmapMut(memmap2::MmapMut);
 
-#[cfg(target_arch = "wasm32")]
+#[cfg(any(miri, target_arch = "wasm32"))]
 pub struct MmapMut(Vec<u8>);
 
-#[cfg(not(target_arch = "wasm32"))]
+#[cfg(not(any(miri, target_arch = "wasm32")))]
 impl MmapMut {
     #[inline]
     pub fn map_anon(len: usize) -> io::Result<Self> {
@@ -82,7 +82,7 @@ impl MmapMut {
     }
 }
 
-#[cfg(target_arch = "wasm32")]
+#[cfg(any(miri, target_arch = "wasm32"))]
 impl MmapMut {
     #[inline]
     pub fn map_anon(len: usize) -> io::Result<Self> {
diff --git a/compiler/rustc_data_structures/src/stack.rs b/compiler/rustc_data_structures/src/stack.rs
index 3d6d0003483..102b3640911 100644
--- a/compiler/rustc_data_structures/src/stack.rs
+++ b/compiler/rustc_data_structures/src/stack.rs
@@ -17,6 +17,18 @@ const STACK_PER_RECURSION: usize = 16 * 1024 * 1024; // 16MB
 ///
 /// Should not be sprinkled around carelessly, as it causes a little bit of overhead.
 #[inline]
+#[cfg(not(miri))]
 pub fn ensure_sufficient_stack<R>(f: impl FnOnce() -> R) -> R {
     stacker::maybe_grow(RED_ZONE, STACK_PER_RECURSION, f)
 }
+
+/// Grows the stack on demand to prevent stack overflow. Call this in strategic locations
+/// to "break up" recursive calls. E.g. almost any call to `visit_expr` or equivalent can benefit
+/// from this.
+///
+/// Should not be sprinkled around carelessly, as it causes a little bit of overhead.
+#[cfg(miri)]
+#[inline]
+pub fn ensure_sufficient_stack<R>(f: impl FnOnce() -> R) -> R {
+    f()
+}