[HACK(eddyb)] arena-allocate but don't intern FnAbis.

compiler/rustc_middle/src/ty/context.rs

@@ -55,7 +55,6 @@ use rustc_span::def_id::{DefPathHash, StableCrateId};
 use rustc_span::source_map::{MultiSpan, SourceMap};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
-use rustc_target::abi::call::FnAbi;
 use rustc_target::abi::{Layout, TargetDataLayout, VariantIdx};
 use rustc_target::spec::abi;
 
@@ -136,7 +135,6 @@ pub struct CtxtInterners<'tcx> {
     const_allocation: InternedSet<'tcx, Allocation>,
     bound_variable_kinds: InternedSet<'tcx, List<ty::BoundVariableKind>>,
     layout: InternedSet<'tcx, Layout>,
-    fn_abi: InternedSet<'tcx, FnAbi<'tcx, Ty<'tcx>>>,
 }
 
 impl<'tcx> CtxtInterners<'tcx> {
@@ -157,7 +155,6 @@ impl<'tcx> CtxtInterners<'tcx> {
             const_allocation: Default::default(),
             bound_variable_kinds: Default::default(),
             layout: Default::default(),
-            fn_abi: Default::default(),
         }
     }
 
@@ -1962,7 +1959,6 @@ impl<'tcx> TyCtxt<'tcx> {
                     self.0.interners.const_allocation.len()
                 )?;
                 writeln!(fmt, "Layout interner: #{}", self.0.interners.layout.len())?;
-                writeln!(fmt, "FnAbi interner: #{}", self.0.interners.fn_abi.len())?;
 
                 Ok(())
             }
@@ -2087,7 +2083,6 @@ direct_interners! {
     const_: mk_const(Const<'tcx>),
     const_allocation: intern_const_alloc(Allocation),
     layout: intern_layout(Layout),
-    fn_abi: intern_fn_abi(FnAbi<'tcx, Ty<'tcx>>),
 }
 
 macro_rules! slice_interners {

compiler/rustc_middle/src/ty/layout.rs

@@ -3118,7 +3118,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
         };
         self.fn_abi_adjust_for_abi(&mut fn_abi, sig.abi)?;
         debug!("fn_abi_new_uncached = {:?}", fn_abi);
-        Ok(self.tcx.intern_fn_abi(fn_abi))
+        Ok(self.tcx.arena.alloc(fn_abi))
     }
 
     fn fn_abi_adjust_for_abi(