Couple of changes to run rustc in miri

compiler/rustc_data_structures/src/memmap.rs

@@ -3,13 +3,13 @@
 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 @@ pub unsafe fn map(file: File) -> io::Result<Self> {
     }
 }
 
-#[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 @@ fn as_ref(&self) -> &[u8] {
     }
 }
 
-#[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 @@ pub fn make_read_only(self) -> std::io::Result<Mmap> {
     }
 }
 
-#[cfg(target_arch = "wasm32")]
+#[cfg(any(miri, target_arch = "wasm32"))]
 impl MmapMut {
     #[inline]
     pub fn map_anon(len: usize) -> io::Result<Self> {

compiler/rustc_data_structures/src/stack.rs

@@ -17,6 +17,18 @@
 ///
 /// 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()
+}

compiler/rustc_driver_impl/src/lib.rs

@@ -89,10 +89,10 @@
 #[macro_use]
 mod print;
 mod session_diagnostics;
-#[cfg(all(unix, any(target_env = "gnu", target_os = "macos")))]
+#[cfg(all(not(miri), unix, any(target_env = "gnu", target_os = "macos")))]
 mod signal_handler;
 
-#[cfg(not(all(unix, any(target_env = "gnu", target_os = "macos"))))]
+#[cfg(not(all(not(miri), unix, any(target_env = "gnu", target_os = "macos"))))]
 mod signal_handler {
     /// On platforms which don't support our signal handler's requirements,
     /// simply use the default signal handler provided by std.
@@ -1474,7 +1474,7 @@ pub fn init_logger(early_dcx: &EarlyDiagCtxt, cfg: rustc_log::LoggerConfig) {
 /// Install our usual `ctrlc` handler, which sets [`rustc_const_eval::CTRL_C_RECEIVED`].
 /// Making this handler optional lets tools can install a different handler, if they wish.
 pub fn install_ctrlc_handler() {
-    #[cfg(not(target_family = "wasm"))]
+    #[cfg(all(not(miri), not(target_family = "wasm")))]
     ctrlc::set_handler(move || {
         // Indicate that we have been signaled to stop, then give the rest of the compiler a bit of
         // time to check CTRL_C_RECEIVED and run its own shutdown logic, but after a short amount

compiler/rustc_errors/src/emitter.rs

@@ -1764,7 +1764,7 @@ fn emit_messages_default_inner(
 
                 let column_width = if let Some(width) = self.diagnostic_width {
                     width.saturating_sub(code_offset)
-                } else if self.ui_testing {
+                } else if self.ui_testing || cfg!(miri) {
                     DEFAULT_COLUMN_WIDTH
                 } else {
                     termize::dimensions()