ast: Replace NamedType with TypeDecl

TypeDecls (alias, structure) are not a types - they declare types.
ast::TypeName is what's used for a ast::Type.

Previously we were trying to automatically convert these to TypeNames in the builder, but having these inherit from ast::Type was extremely error prone.

reader/spirv was actually constructing ast::Structs and using them as types, which is invalid.

Change-Id: I05773ad6d488626606019015b84217a5a55a8e8a
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/53802
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>

src/transform/decompose_storage_access.cc

@@ -332,7 +332,7 @@ void InsertGlobal(CloneContext& ctx,
 }
 
 /// @returns the unwrapped, user-declared constructed type of ty.
-const ast::NamedType* ConstructedTypeOf(const sem::Type* ty) {
+const ast::TypeDecl* ConstructedTypeOf(const sem::Type* ty) {
   while (true) {
     if (auto* ref = ty->As<sem::Reference>()) {
       ty = ref->StoreType();
@@ -414,7 +414,7 @@ struct DecomposeStorageAccess::State {
   /// @param var_user the variable user
   /// @return the name of the function that performs the load
   Symbol LoadFunc(CloneContext& ctx,
-                  const ast::NamedType* insert_after,
+                  const ast::TypeDecl* insert_after,
                   const sem::Type* buf_ty,
                   const sem::Type* el_ty,
                   const sem::VariableUser* var_user) {
@@ -490,7 +490,7 @@ struct DecomposeStorageAccess::State {
   /// @param var_user the variable user
   /// @return the name of the function that performs the store
   Symbol StoreFunc(CloneContext& ctx,
-                   const ast::NamedType* insert_after,
+                   const ast::TypeDecl* insert_after,
                    const sem::Type* buf_ty,
                    const sem::Type* el_ty,
                    const sem::VariableUser* var_user) {

src/transform/first_index_offset.cc

@@ -133,14 +133,14 @@ Output FirstIndexOffset::Run(const Program* in, const DataMap& data) {
       instance_index_offset = offset;
       offset += 4;
     }
-    auto* struct_type =
+    auto* struct_ =
         ctx.dst->Structure(ctx.dst->Sym(), std::move(members),
                            {ctx.dst->create<ast::StructBlockDecoration>()});
 
     // Create a global to hold the uniform buffer
     Symbol buffer_name = ctx.dst->Sym();
-    ctx.dst->Global(buffer_name, struct_type, ast::StorageClass::kUniform,
-                    nullptr,
+    ctx.dst->Global(buffer_name, ctx.dst->ty.Of(struct_),
+                    ast::StorageClass::kUniform, nullptr,
                     ast::DecorationList{
                         ctx.dst->create<ast::BindingDecoration>(ub_binding),
                         ctx.dst->create<ast::GroupDecoration>(ub_group),

src/transform/single_entry_point.cc

@@ -69,7 +69,7 @@ Output SingleEntryPoint::Run(const Program* in, const DataMap& data) {
   // Clone any module-scope variables, types, and functions that are statically
   // referenced by the target entry point.
   for (auto* decl : in->AST().GlobalDeclarations()) {
-    if (auto* ty = decl->As<ast::NamedType>()) {
+    if (auto* ty = decl->As<ast::TypeDecl>()) {
       // TODO(jrprice): Strip unused types.
       out.AST().AddConstructedType(ctx.Clone(ty));
     } else if (auto* var = decl->As<ast::Variable>()) {

src/transform/vertex_pulling.cc

@@ -216,8 +216,8 @@ struct State {
     for (uint32_t i = 0; i < cfg.vertex_state.size(); ++i) {
       // The decorated variable with struct type
       ctx.dst->Global(
-          GetVertexBufferName(i), struct_type, ast::StorageClass::kStorage,
-          ast::Access::kRead,
+          GetVertexBufferName(i), ctx.dst->ty.Of(struct_type),
+          ast::StorageClass::kStorage, ast::Access::kRead,
           ast::DecorationList{
               ctx.dst->create<ast::BindingDecoration>(i),
               ctx.dst->create<ast::GroupDecoration>(cfg.pulling_group),
@@ -485,7 +485,8 @@ struct State {
       auto* new_struct = ctx.dst->Structure(ctx.dst->Sym(), new_members);
 
       // Create a new function parameter with this struct.
-      auto* new_param = ctx.dst->Param(ctx.dst->Sym(), new_struct);
+      auto* new_param =
+          ctx.dst->Param(ctx.dst->Sym(), ctx.dst->ty.Of(new_struct));
       new_function_parameters.push_back(new_param);
 
       // Copy values from the new parameter to the function-scope variable.