codegen: fix OperandRef subtype handling

compiler/rustc_codegen_ssa/src/mir/mod.rs

@@ -1,21 +1,31 @@
 use crate::base;
 use crate::traits::*;
+use rustc_index::bit_set::BitSet;
+use rustc_index::IndexVec;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::ErrorHandled;
+use rustc_middle::mir::traversal;
 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt, TyAndLayout};
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt, TypeFoldable, TypeVisitableExt};
 use rustc_target::abi::call::{FnAbi, PassMode};
 
 use std::iter;
 
-use rustc_index::bit_set::BitSet;
-use rustc_index::IndexVec;
+mod analyze;
+mod block;
+pub mod constant;
+pub mod coverageinfo;
+pub mod debuginfo;
+mod intrinsic;
+mod locals;
+pub mod operand;
+pub mod place;
+mod rvalue;
+mod statement;
 
 use self::debuginfo::{FunctionDebugContext, PerLocalVarDebugInfo};
-use self::place::PlaceRef;
-use rustc_middle::mir::traversal;
-
 use self::operand::{OperandRef, OperandValue};
+use self::place::PlaceRef;
 
 // Used for tracking the state of generated basic blocks.
 enum CachedLlbb<T> {
@@ -91,7 +101,7 @@ pub struct FunctionCx<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
     ///
     /// Avoiding allocs can also be important for certain intrinsics,
     /// notably `expect`.
-    locals: IndexVec<mir::Local, LocalRef<'tcx, Bx::Value>>,
+    locals: locals::Locals<'tcx, Bx::Value>,
 
     /// All `VarDebugInfo` from the MIR body, partitioned by `Local`.
     /// This is `None` if no var`#[non_exhaustive]`iable debuginfo/names are needed.
@@ -192,7 +202,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         cleanup_kinds,
         landing_pads: IndexVec::from_elem(None, &mir.basic_blocks),
         funclets: IndexVec::from_fn_n(|_| None, mir.basic_blocks.len()),
-        locals: IndexVec::new(),
+        locals: locals::Locals::empty(),
         debug_context,
         per_local_var_debug_info: None,
         caller_location: None,
@@ -223,7 +233,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     let memory_locals = analyze::non_ssa_locals(&fx);
 
     // Allocate variable and temp allocas
-    fx.locals = {
+    let local_values = {
         let args = arg_local_refs(&mut start_bx, &mut fx, &memory_locals);
 
         let mut allocate_local = |local| {
@@ -256,6 +266,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
             .chain(mir.vars_and_temps_iter().map(allocate_local))
             .collect()
     };
+    fx.initialize_locals(local_values);
 
     // Apply debuginfo to the newly allocated locals.
     fx.debug_introduce_locals(&mut start_bx);
@@ -289,14 +300,13 @@ fn arg_local_refs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         .enumerate()
         .map(|(arg_index, local)| {
             let arg_decl = &mir.local_decls[local];
+            let arg_ty = fx.monomorphize(arg_decl.ty);
 
             if Some(local) == mir.spread_arg {
                 // This argument (e.g., the last argument in the "rust-call" ABI)
                 // is a tuple that was spread at the ABI level and now we have
                 // to reconstruct it into a tuple local variable, from multiple
                 // individual LLVM function arguments.
-
-                let arg_ty = fx.monomorphize(arg_decl.ty);
                 let ty::Tuple(tupled_arg_tys) = arg_ty.kind() else {
                     bug!("spread argument isn't a tuple?!");
                 };
@@ -331,8 +341,6 @@ fn arg_local_refs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
             }
 
             if fx.fn_abi.c_variadic && arg_index == fx.fn_abi.args.len() {
-                let arg_ty = fx.monomorphize(arg_decl.ty);
-
                 let va_list = PlaceRef::alloca(bx, bx.layout_of(arg_ty));
                 bx.va_start(va_list.llval);
 
@@ -429,14 +437,3 @@ fn arg_local_refs<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 
     args
 }
-
-mod analyze;
-mod block;
-pub mod constant;
-pub mod coverageinfo;
-pub mod debuginfo;
-mod intrinsic;
-pub mod operand;
-pub mod place;
-mod rvalue;
-mod statement;