ast: Remove no-arg constructor for ast::LoopStatement

In a near-future change, AST nodes, such as ast::BlockStatement will no longer
be std::unique_ptrs, and will have to be constructed and owned by an external
class. This means AST nodes can no longer allocate default child nodes.

Bug: tint:322
Change-Id: I3db9b3c037896f07b84b14b7b8d4da0f066b69b0
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/32679
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>

src/ast/loop_statement.cc

@@ -17,11 +17,6 @@
 namespace tint {
 namespace ast {
 
-LoopStatement::LoopStatement()
-    : Statement(),
-      body_(std::make_unique<BlockStatement>()),
-      continuing_(std::make_unique<BlockStatement>()) {}
-
 LoopStatement::LoopStatement(std::unique_ptr<BlockStatement> body,
                              std::unique_ptr<BlockStatement> continuing)
     : Statement(), body_(std::move(body)), continuing_(std::move(continuing)) {}

src/ast/loop_statement.h

@@ -27,8 +27,6 @@ namespace ast {
 /// A loop statement
 class LoopStatement : public Statement {
  public:
-  /// Constructor
-  LoopStatement();
   /// Constructor
   /// @param body the body statements
   /// @param continuing the continuing statements

src/ast/loop_statement_test.cc

@@ -58,7 +58,7 @@ TEST_F(LoopStatementTest, Creation_WithSource) {
 }
 
 TEST_F(LoopStatementTest, IsLoop) {
-  LoopStatement l;
+  LoopStatement l(create<BlockStatement>(), create<BlockStatement>());
   EXPECT_TRUE(l.IsLoop());
 }
 

src/reader/spirv/function.cc

@@ -2207,7 +2207,10 @@ bool FunctionEmitter::EmitSwitchStart(const BlockInfo& block_info) {
 }
 
 bool FunctionEmitter::EmitLoopStart(const Construct* construct) {
-  auto* loop = AddStatement(std::make_unique<ast::LoopStatement>())->AsLoop();
+  auto* loop = AddStatement(std::make_unique<ast::LoopStatement>(
+                                std::make_unique<ast::BlockStatement>(),
+                                std::make_unique<ast::BlockStatement>()))
+                   ->AsLoop();
   PushNewStatementBlock(
       construct, construct->end_id,
       [loop](StatementBlock* s) { loop->set_body(std::move(s->statements_)); });

src/writer/spirv/builder_loop_test.cc

@@ -40,7 +40,8 @@ TEST_F(BuilderTest, Loop_Empty) {
   // loop {
   // }
 
-  ast::LoopStatement expr;
+  ast::LoopStatement expr(create<ast::BlockStatement>(),
+                          create<ast::BlockStatement>());
 
   ASSERT_TRUE(td.DetermineResultType(&expr)) << td.error();
   b.push_function(Function{});