SkSL performance improvements

src/sksl/ir/SkSLSwizzle.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
  
 #ifndef SKSL_SWIZZLE
 #define SKSL_SWIZZLE
 
 #include "SkSLExpression.h"
 #include "SkSLUtil.h"
 
 namespace SkSL {
 
 /**
  * Given a type and a swizzle component count, returns the type that will result from swizzling. For 
  * instance, swizzling a vec3 with two components will result in a vec2. It is possible to swizzle
  * with more components than the source vector, as in 'vec2(1).xxxx'.
  */
-static std::shared_ptr<Type> get_type(Expression& value, 
-                                      size_t count) {
-    std::shared_ptr<Type> base = value.fType->componentType();
+static const Type& get_type(Expression& value, size_t count) {
+    const Type& base = value.fType.componentType();
     if (count == 1) {
         return base;
     }
     if (base == kFloat_Type) {
         switch (count) {
             case 2: return kVec2_Type;
             case 3: return kVec3_Type;
             case 4: return kVec4_Type;
         }
     } else if (base == kDouble_Type) {
@@ skipping 45 matching lines @@
 
     const std::unique_ptr<Expression> fBase;
     const std::vector<int> fComponents;
 
     typedef Expression INHERITED;
 };
 
 } // namespace
 
 #endif