Replace VariableDecoration::(Is|As)Builtin with Castable

Change-Id: I49d970301c46cfe29d7b22e18abb443daa0c8073
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/34307
Reviewed-by: dan sinclair <dsinclair@chromium.org>

src/ast/binding_decoration_test.cc

@@ -28,12 +28,13 @@ TEST_F(BindingDecorationTest, Creation) {
 }
 
 TEST_F(BindingDecorationTest, Is) {
-  BindingDecoration d{2, Source{}};
-  EXPECT_TRUE(d.Is<BindingDecoration>());
-  EXPECT_FALSE(d.IsBuiltin());
-  EXPECT_FALSE(d.IsConstantId());
-  EXPECT_FALSE(d.IsLocation());
-  EXPECT_FALSE(d.IsSet());
+  BindingDecoration bd{2, Source{}};
+  Decoration* d = &bd;
+  EXPECT_TRUE(d->Is<BindingDecoration>());
+  EXPECT_FALSE(d->Is<BuiltinDecoration>());
+  EXPECT_FALSE(bd.IsConstantId());
+  EXPECT_FALSE(bd.IsLocation());
+  EXPECT_FALSE(bd.IsSet());
 }
 
 TEST_F(BindingDecorationTest, ToStr) {

src/ast/builtin_decoration.cc

@@ -22,10 +22,6 @@ BuiltinDecoration::BuiltinDecoration(Builtin builtin, const Source& source)
 
 BuiltinDecoration::~BuiltinDecoration() = default;
 
-bool BuiltinDecoration::IsBuiltin() const {
-  return true;
-}
-
 void BuiltinDecoration::to_str(std::ostream& out, size_t indent) const {
   make_indent(out, indent);
   out << "BuiltinDecoration{" << builtin_ << "}" << std::endl;

src/ast/builtin_decoration.h

@@ -31,9 +31,6 @@ class BuiltinDecoration
   BuiltinDecoration(Builtin builtin, const Source& source);
   ~BuiltinDecoration() override;
 
-  /// @returns true if this is a builtin decoration
-  bool IsBuiltin() const override;
-
   /// @returns the builtin value
   Builtin value() const { return builtin_; }
 

src/ast/builtin_decoration_test.cc

@@ -31,7 +31,7 @@ TEST_F(BuiltinDecorationTest, Is) {
   BuiltinDecoration bd{Builtin::kFragDepth, Source{}};
   Decoration* d = &bd;
   EXPECT_FALSE(d->Is<BindingDecoration>());
-  EXPECT_TRUE(bd.IsBuiltin());
+  EXPECT_TRUE(d->Is<BuiltinDecoration>());
   EXPECT_FALSE(bd.IsConstantId());
   EXPECT_FALSE(bd.IsLocation());
   EXPECT_FALSE(bd.IsSet());

src/ast/constant_id_decoration_test.cc

@@ -31,7 +31,7 @@ TEST_F(ConstantIdDecorationTest, Is) {
   ConstantIdDecoration cd{27, Source{}};
   Decoration* d = &cd;
   EXPECT_FALSE(d->Is<BindingDecoration>());
-  EXPECT_FALSE(cd.IsBuiltin());
+  EXPECT_FALSE(d->Is<BuiltinDecoration>());
   EXPECT_TRUE(cd.IsConstantId());
   EXPECT_FALSE(cd.IsLocation());
   EXPECT_FALSE(cd.IsSet());

src/ast/decorated_variable.cc

@@ -16,6 +16,7 @@
 
 #include <cassert>
 
+#include "src/ast/builtin_decoration.h"
 #include "src/ast/constant_id_decoration.h"
 
 namespace tint {
@@ -41,7 +42,7 @@ bool DecoratedVariable::HasLocationDecoration() const {
 
 bool DecoratedVariable::HasBuiltinDecoration() const {
   for (auto* deco : decorations_) {
-    if (deco->IsBuiltin()) {
+    if (deco->Is<BuiltinDecoration>()) {
       return true;
     }
   }

src/ast/function.cc

@@ -163,8 +163,8 @@ Function::referenced_builtin_variables() const {
       continue;
     }
     for (auto* deco : var->AsDecorated()->decorations()) {
-      if (deco->IsBuiltin()) {
-        ret.push_back({var, deco->AsBuiltin()});
+      if (auto* builtin = deco->As<BuiltinDecoration>()) {
+        ret.push_back({var, builtin});
         break;
       }
     }

src/ast/location_decoration_test.cc

@@ -33,7 +33,7 @@ TEST_F(LocationDecorationTest, Is) {
   LocationDecoration ld{2, Source{}};
   Decoration* d = &ld;
   EXPECT_FALSE(d->Is<BindingDecoration>());
-  EXPECT_FALSE(ld.IsBuiltin());
+  EXPECT_FALSE(d->Is<BuiltinDecoration>());
   EXPECT_FALSE(ld.IsConstantId());
   EXPECT_TRUE(ld.IsLocation());
   EXPECT_FALSE(ld.IsSet());

src/ast/set_decoration_test.cc

@@ -31,7 +31,7 @@ TEST_F(SetDecorationTest, Is) {
   SetDecoration sd{2, Source{}};
   Decoration* d = &sd;
   EXPECT_FALSE(d->Is<BindingDecoration>());
-  EXPECT_FALSE(sd.IsBuiltin());
+  EXPECT_FALSE(d->Is<BuiltinDecoration>());
   EXPECT_FALSE(sd.IsConstantId());
   EXPECT_FALSE(sd.IsLocation());
   EXPECT_TRUE(sd.IsSet());

src/ast/variable_decoration.cc

@@ -35,10 +35,6 @@ DecorationKind VariableDecoration::GetKind() const {
   return Kind;
 }
 
-bool VariableDecoration::IsBuiltin() const {
-  return false;
-}
-
 bool VariableDecoration::IsLocation() const {
   return false;
 }
@@ -51,11 +47,6 @@ bool VariableDecoration::IsSet() const {
   return false;
 }
 
-BuiltinDecoration* VariableDecoration::AsBuiltin() {
-  assert(IsBuiltin());
-  return static_cast<BuiltinDecoration*>(this);
-}
-
 ConstantIdDecoration* VariableDecoration::AsConstantId() {
   assert(IsConstantId());
   return static_cast<ConstantIdDecoration*>(this);

src/ast/variable_decoration.h

@@ -25,7 +25,6 @@
 namespace tint {
 namespace ast {
 
-class BuiltinDecoration;
 class ConstantIdDecoration;
 class LocationDecoration;
 class SetDecoration;
@@ -41,8 +40,6 @@ class VariableDecoration : public Castable<VariableDecoration, Decoration> {
   /// @return the decoration kind
   DecorationKind GetKind() const override;
 
-  /// @returns true if this is a builtin decoration
-  virtual bool IsBuiltin() const;
   /// @returns true if this is a constant id decoration
   virtual bool IsConstantId() const;
   /// @returns true if this is a location decoration
@@ -50,8 +47,6 @@ class VariableDecoration : public Castable<VariableDecoration, Decoration> {
   /// @returns true if this is a set decoration
   virtual bool IsSet() const;
 
-  /// @returns the decoration as a builtin decoration
-  BuiltinDecoration* AsBuiltin();
   /// @returns the decoration as a constant id decoration
   ConstantIdDecoration* AsConstantId();
   /// @returns the decoration as a location decoration