Adding const As.* functions to statement class

Change-Id: Ie9c0cecfce1ebb7decf377cee7053fb7ae0dee9c
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/20260
Reviewed-by: David Neto <dneto@google.com>

src/ast/statement.cc

@@ -98,6 +98,76 @@ bool Statement::IsVariableDecl() const {
   return false;
 }
 
+const AssignmentStatement* Statement::AsAssign() const {
+  assert(IsAssign());
+  return static_cast<const AssignmentStatement*>(this);
+}
+
+const BreakStatement* Statement::AsBreak() const {
+  assert(IsBreak());
+  return static_cast<const BreakStatement*>(this);
+}
+
+const CaseStatement* Statement::AsCase() const {
+  assert(IsCase());
+  return static_cast<const CaseStatement*>(this);
+}
+
+const ContinueStatement* Statement::AsContinue() const {
+  assert(IsContinue());
+  return static_cast<const ContinueStatement*>(this);
+}
+
+const ElseStatement* Statement::AsElse() const {
+  assert(IsElse());
+  return static_cast<const ElseStatement*>(this);
+}
+
+const FallthroughStatement* Statement::AsFallthrough() const {
+  assert(IsFallthrough());
+  return static_cast<const FallthroughStatement*>(this);
+}
+
+const IfStatement* Statement::AsIf() const {
+  assert(IsIf());
+  return static_cast<const IfStatement*>(this);
+}
+
+const KillStatement* Statement::AsKill() const {
+  assert(IsKill());
+  return static_cast<const KillStatement*>(this);
+}
+
+const LoopStatement* Statement::AsLoop() const {
+  assert(IsLoop());
+  return static_cast<const LoopStatement*>(this);
+}
+
+const NopStatement* Statement::AsNop() const {
+  assert(IsNop());
+  return static_cast<const NopStatement*>(this);
+}
+
+const ReturnStatement* Statement::AsReturn() const {
+  assert(IsReturn());
+  return static_cast<const ReturnStatement*>(this);
+}
+
+const SwitchStatement* Statement::AsSwitch() const {
+  assert(IsSwitch());
+  return static_cast<const SwitchStatement*>(this);
+}
+
+const UnlessStatement* Statement::AsUnless() const {
+  assert(IsUnless());
+  return static_cast<const UnlessStatement*>(this);
+}
+
+const VariableDeclStatement* Statement::AsVariableDecl() const {
+  assert(IsVariableDecl());
+  return static_cast<const VariableDeclStatement*>(this);
+}
+
 AssignmentStatement* Statement::AsAssign() {
   assert(IsAssign());
   return static_cast<AssignmentStatement*>(this);

src/ast/statement.h

@@ -72,6 +72,35 @@ class Statement : public Node {
   /// @returns true if this is an variable statement
   virtual bool IsVariableDecl() const;
 
+  /// @returns the statement as a const assign statement
+  const AssignmentStatement* AsAssign() const;
+  /// @returns the statement as a const break statement
+  const BreakStatement* AsBreak() const;
+  /// @returns the statement as a const case statement
+  const CaseStatement* AsCase() const;
+  /// @returns the statement as a const continue statement
+  const ContinueStatement* AsContinue() const;
+  /// @returns the statement as a const else statement
+  const ElseStatement* AsElse() const;
+  /// @returns the statement as a const fallthrough statement
+  const FallthroughStatement* AsFallthrough() const;
+  /// @returns the statement as a const if statement
+  const IfStatement* AsIf() const;
+  /// @returns the statement as a const kill statement
+  const KillStatement* AsKill() const;
+  /// @returns the statement as a const loop statement
+  const LoopStatement* AsLoop() const;
+  /// @returns the statement as a const nop statement
+  const NopStatement* AsNop() const;
+  /// @returns the statement as a const return statement
+  const ReturnStatement* AsReturn() const;
+  /// @returns the statement as a const switch statement
+  const SwitchStatement* AsSwitch() const;
+  /// @returns the statement as a const unless statement
+  const UnlessStatement* AsUnless() const;
+  /// @returns the statement as a const variable statement
+  const VariableDeclStatement* AsVariableDecl() const;
+
   /// @returns the statement as an assign statement
   AssignmentStatement* AsAssign();
   /// @returns the statement as a break statement