WIP

carbon-language · Nov 12, 2024 · 1439655 · 1439655
1 parent 8335d1e
commit 1439655
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Showing 3 changed files with 14 additions and 6 deletions.
diff --git a/MODULE.bazel.lock b/MODULE.bazel.lock
diff --git a/common/array_stack.h b/common/array_stack.h
@@ -47,6 +47,13 @@ class ArrayStack {
     return llvm::ArrayRef(values_).slice(array_offsets_.back());
   }
 
+  // Returns the top array from the stack in such a way that the array's
+  // contents can be modified by the caller.
+  auto PeekMutableArray() -> llvm::MutableArrayRef<ValueT> {
+    CARBON_CHECK(!array_offsets_.empty());
+    return llvm::MutableArrayRef(values_).slice(array_offsets_.back());
+  }
+
   // Returns the array at a specific index.
   auto PeekArrayAt(int index) const -> llvm::ArrayRef<ValueT> {
     auto ref = llvm::ArrayRef(values_).slice(array_offsets_[index]);

diff --git a/toolchain/check/handle_class.cpp b/toolchain/check/handle_class.cpp
@@ -296,6 +296,8 @@ auto HandleParseNode(Context& context, Parse::ClassDefinitionStartId node_id)
   context.inst_block_stack().Push();
   context.node_stack().Push(node_id, class_id);
   context.struct_type_fields_stack().PushArray();
+  context.struct_type_fields_stack().AppendToTop(
+      {.name_id = SemIR::NameId::Vptr, .type_id = context.GetTupleType({})});
 
   // TODO: Handle the case where there's control flow in the class body. For
   // example:
@@ -668,10 +670,9 @@ static auto CheckCompleteClassType(Context& context, Parse::NodeId node_id,
   }
 
   if (defining_vtable_ptr) {
-    context.struct_type_fields_stack().PrependToTop(
-        {.name_id = SemIR::NameId::Vptr,
-         .type_id = context.GetPointerType(
-             context.GetBuiltinType(SemIR::BuiltinInstKind::VtableType))});
+    context.struct_type_fields_stack().PeekMutableArray().front().type_id =
+        context.GetPointerType(
+            context.GetBuiltinType(SemIR::BuiltinInstKind::VtableType));
   }
 
   auto fields_id = context.struct_type_fields().AddCanonical(