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(const Context& context, Expression& value, size_t count) {
+    const Type& base = value.fType.componentType();
     if (count == 1) {
         return base;
     }
-    if (base == kFloat_Type) {
+    if (base == *context.fFloat_Type) {
         switch (count) {
-            case 2: return kVec2_Type;
-            case 3: return kVec3_Type;
-            case 4: return kVec4_Type;
+            case 2: return *context.fVec2_Type;
+            case 3: return *context.fVec3_Type;
+            case 4: return *context.fVec4_Type;
         }
-    } else if (base == kDouble_Type) {
+    } else if (base == *context.fDouble_Type) {
         switch (count) {
-            case 2: return kDVec2_Type;
-            case 3: return kDVec3_Type;
-            case 4: return kDVec4_Type;
+            case 2: return *context.fDVec2_Type;
+            case 3: return *context.fDVec3_Type;
+            case 4: return *context.fDVec4_Type;
         }
-    } else if (base == kInt_Type) {
+    } else if (base == *context.fInt_Type) {
         switch (count) {
-            case 2: return kIVec2_Type;
-            case 3: return kIVec3_Type;
-            case 4: return kIVec4_Type;
+            case 2: return *context.fIVec2_Type;
+            case 3: return *context.fIVec3_Type;
+            case 4: return *context.fIVec4_Type;
         }
-    } else if (base == kUInt_Type) {
+    } else if (base == *context.fUInt_Type) {
         switch (count) {
-            case 2: return kUVec2_Type;
-            case 3: return kUVec3_Type;
-            case 4: return kUVec4_Type;
+            case 2: return *context.fUVec2_Type;
+            case 3: return *context.fUVec3_Type;
+            case 4: return *context.fUVec4_Type;
         }
-    } else if (base == kBool_Type) {
+    } else if (base == *context.fBool_Type) {
         switch (count) {
-            case 2: return kBVec2_Type;
-            case 3: return kBVec3_Type;
-            case 4: return kBVec4_Type;
+            case 2: return *context.fBVec2_Type;
+            case 3: return *context.fBVec3_Type;
+            case 4: return *context.fBVec4_Type;
         }
     }
     ABORT("cannot swizzle %s\n", value.description().c_str());
 }
 
 /**
  * Represents a vector swizzle operation such as 'vec2(1, 2, 3).zyx'.
  */
 struct Swizzle : public Expression {
-    Swizzle(std::unique_ptr<Expression> base, std::vector<int> components)
-    : INHERITED(base->fPosition, kSwizzle_Kind, get_type(*base, components.size()))
+    Swizzle(const Context& context, std::unique_ptr<Expression> base, std::vector<int> components)
+    : INHERITED(base->fPosition, kSwizzle_Kind, get_type(context, *base, components.size()))
     , fBase(std::move(base))
     , fComponents(std::move(components)) {
         ASSERT(fComponents.size() >= 1 && fComponents.size() <= 4);
     }
 
     std::string description() const override {
         std::string result = fBase->description() + ".";
         for (int x : fComponents) {
             result += "xyzw"[x];
         }
         return result;
     }
 
     const std::unique_ptr<Expression> fBase;
     const std::vector<int> fComponents;
 
     typedef Expression INHERITED;
 };
 
 } // namespace
 
 #endif