Rollup merge of #134498 - oli-obk:push-wmxynprsyxvr, r=compiler-errors

Fix cycle error only occurring with -Zdump-mir

fixes #134205

During mir dumping, we evaluate static items to render their allocations. If a static item refers to itself, its own MIR will have a reference to itself, so during mir dumping we end up evaluating the static again, causing us to try to build MIR again (mir dumping happens during MIR building).

Thus I disabled evaluation of statics during MIR dumps in case the MIR body isn't far enough along yet to be able to be guaranteed cycle free.

1 files changed, 15 insertions, 9 deletions

diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs
index 47522f00bb1..24d2478f770 100644
--- a/compiler/rustc_middle/src/mir/pretty.rs
+++ b/compiler/rustc_middle/src/mir/pretty.rs
@@ -1555,16 +1555,22 @@ pub fn write_allocations<'tcx>(
                 write!(w, " (vtable: impl {dyn_ty} for {ty})")?
             }
             Some(GlobalAlloc::Static(did)) if !tcx.is_foreign_item(did) => {
-                match tcx.eval_static_initializer(did) {
-                    Ok(alloc) => {
-                        write!(w, " (static: {}, ", tcx.def_path_str(did))?;
-                        write_allocation_track_relocs(w, alloc)?;
+                write!(w, " (static: {}", tcx.def_path_str(did))?;
+                if body.phase <= MirPhase::Runtime(RuntimePhase::PostCleanup)
+                    && tcx.hir().body_const_context(body.source.def_id()).is_some()
+                {
+                    // Statics may be cyclic and evaluating them too early
+                    // in the MIR pipeline may cause cycle errors even though
+                    // normal compilation is fine.
+                    write!(w, ")")?;
+                } else {
+                    match tcx.eval_static_initializer(did) {
+                        Ok(alloc) => {
+                            write!(w, ", ")?;
+                            write_allocation_track_relocs(w, alloc)?;
+                        }
+                        Err(_) => write!(w, ", error during initializer evaluation)")?,
                     }
-                    Err(_) => write!(
-                        w,
-                        " (static: {}, error during initializer evaluation)",
-                        tcx.def_path_str(did)
-                    )?,
                 }
             }
             Some(GlobalAlloc::Static(did)) => {