Add while statement parsing.

This CL adds parsing for the WGSL `while` statement.

Bug: tint:1425
Change-Id: Ibce5e28568935ca4f51b5ac33e7a60af7a916b4a
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/93540
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>

src/tint/sem/type_mappings.h

@@ -34,6 +34,7 @@ class SwitchStatement;
 class Type;
 class TypeDecl;
 class Variable;
+class WhileStatement;
 }  // namespace tint::ast
 namespace tint::sem {
 class Array;
@@ -50,6 +51,7 @@ class StructMember;
 class SwitchStatement;
 class Type;
 class Variable;
+class WhileStatement;
 }  // namespace tint::sem
 
 namespace tint::sem {
@@ -74,6 +76,7 @@ struct TypeMappings {
     Type* operator()(ast::Type*);
     Type* operator()(ast::TypeDecl*);
     Variable* operator()(ast::Variable*);
+    WhileStatement* operator()(ast::WhileStatement*);
     //! @endcond
 };
 

src/tint/sem/while_statement.cc

@@ -0,0 +1,34 @@
+// Copyright 2022 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "src/tint/sem/while_statement.h"
+
+#include "src/tint/program_builder.h"
+
+TINT_INSTANTIATE_TYPEINFO(tint::sem::WhileStatement);
+
+namespace tint::sem {
+
+WhileStatement::WhileStatement(const ast::WhileStatement* declaration,
+                               const CompoundStatement* parent,
+                               const sem::Function* function)
+    : Base(declaration, parent, function) {}
+
+WhileStatement::~WhileStatement() = default;
+
+const ast::WhileStatement* WhileStatement::Declaration() const {
+    return static_cast<const ast::WhileStatement*>(Base::Declaration());
+}
+
+}  // namespace tint::sem

src/tint/sem/while_statement.h

@@ -0,0 +1,60 @@
+// Copyright 2022 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0(the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef SRC_TINT_SEM_WHILE_STATEMENT_H_
+#define SRC_TINT_SEM_WHILE_STATEMENT_H_
+
+#include "src/tint/sem/statement.h"
+
+// Forward declarations
+namespace tint::ast {
+class WhileStatement;
+}  // namespace tint::ast
+namespace tint::sem {
+class Expression;
+}  // namespace tint::sem
+
+namespace tint::sem {
+
+/// Holds semantic information about a while statement
+class WhileStatement final : public Castable<WhileStatement, CompoundStatement> {
+  public:
+    /// Constructor
+    /// @param declaration the AST node for this while statement
+    /// @param parent the owning statement
+    /// @param function the owning function
+    WhileStatement(const ast::WhileStatement* declaration,
+                   const CompoundStatement* parent,
+                   const sem::Function* function);
+
+    /// Destructor
+    ~WhileStatement() override;
+
+    /// @returns the AST node
+    const ast::WhileStatement* Declaration() const;
+
+    /// @returns the whilecondition expression
+    const Expression* Condition() const { return condition_; }
+
+    /// Sets the while condition expression
+    /// @param condition the while condition expression
+    void SetCondition(const Expression* condition) { condition_ = condition; }
+
+  private:
+    const Expression* condition_ = nullptr;
+};
+
+}  // namespace tint::sem
+
+#endif  // SRC_TINT_SEM_WHILE_STATEMENT_H_