Replace ArrayDecoration::(Is|As)Stride with Castable

Change-Id: I0a346226996c86a6f976b51f69ae4df32806a797
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/34305
Reviewed-by: dan sinclair <dsinclair@chromium.org>

src/ast/array_decoration.cc

@@ -31,14 +31,5 @@ DecorationKind ArrayDecoration::GetKind() const {
   return Kind;
 }
 
-bool ArrayDecoration::IsStride() const {
-  return false;
-}
-
-StrideDecoration* ArrayDecoration::AsStride() {
-  assert(IsStride());
-  return static_cast<StrideDecoration*>(this);
-}
-
 }  // namespace ast
 }  // namespace tint

src/ast/array_decoration.h

@@ -37,12 +37,6 @@ class ArrayDecoration : public Castable<ArrayDecoration, Decoration> {
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @returns true if this is a stride decoration
-  virtual bool IsStride() const;
-
-  /// @returns the decoration as a stride decoration
-  StrideDecoration* AsStride();
-
  protected:
   /// Constructor
   /// @param source the source of this decoration

src/ast/stride_decoration.cc

@@ -20,10 +20,6 @@ namespace ast {
 StrideDecoration::StrideDecoration(uint32_t stride, const Source& source)
     : Base(source), stride_(stride) {}
 
-bool StrideDecoration::IsStride() const {
-  return true;
-}
-
 StrideDecoration::~StrideDecoration() = default;
 
 void StrideDecoration::to_str(std::ostream& out, size_t indent) const {

src/ast/stride_decoration.h

@@ -33,9 +33,6 @@ class StrideDecoration : public Castable<StrideDecoration, ArrayDecoration> {
   StrideDecoration(uint32_t stride, const Source& source);
   ~StrideDecoration() override;
 
-  /// @returns true if this is a stride decoration
-  bool IsStride() const override;
-
   /// @returns the stride value
   uint32_t stride() const { return stride_; }
 

src/ast/stride_decoration_test.cc

@@ -29,7 +29,7 @@ TEST_F(StrideDecorationTest, Creation) {
 
 TEST_F(StrideDecorationTest, Is) {
   StrideDecoration d{2, Source{}};
-  EXPECT_TRUE(d.IsStride());
+  EXPECT_TRUE(d.Is<StrideDecoration>());
 }
 
 TEST_F(StrideDecorationTest, Source) {

src/ast/type/array_type.cc

@@ -65,8 +65,8 @@ uint64_t ArrayType::BaseAlignment(MemoryLayout mem_layout) const {
 
 uint32_t ArrayType::array_stride() const {
   for (auto* deco : decos_) {
-    if (deco->IsStride()) {
-      return deco->AsStride()->stride();
+    if (auto* stride = deco->As<ast::StrideDecoration>()) {
+      return stride->stride();
     }
   }
   return 0;
@@ -74,7 +74,7 @@ uint32_t ArrayType::array_stride() const {
 
 bool ArrayType::has_array_stride() const {
   for (auto* deco : decos_) {
-    if (deco->IsStride()) {
+    if (deco->Is<ast::StrideDecoration>()) {
       return true;
     }
   }