1 /* 2 * Copyright 2016 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SKSL_EXPRESSION 9 #define SKSL_EXPRESSION 10 11 #include "SkSLType.h" 12 #include "SkSLVariable.h" 13 14 #include <unordered_map> 15 16 namespace SkSL { 17 18 struct Expression; 19 class IRGenerator; 20 21 typedef std::unordered_map<const Variable*, std::unique_ptr<Expression>*> DefinitionMap; 22 23 /** 24 * Abstract supertype of all expressions. 25 */ 26 struct Expression : public IRNode { 27 enum Kind { 28 kBinary_Kind, 29 kBoolLiteral_Kind, 30 kConstructor_Kind, 31 kIntLiteral_Kind, 32 kFieldAccess_Kind, 33 kFloatLiteral_Kind, 34 kFunctionReference_Kind, 35 kFunctionCall_Kind, 36 kIndex_Kind, 37 kPrefix_Kind, 38 kPostfix_Kind, 39 kSwizzle_Kind, 40 kVariableReference_Kind, 41 kTernary_Kind, 42 kTypeReference_Kind, 43 kDefined_Kind 44 }; 45 46 Expression(Position position, Kind kind, const Type& type) 47 : INHERITED(position) 48 , fKind(kind) 49 , fType(std::move(type)) {} 50 51 virtual bool isConstant() const { 52 return false; 53 } 54 55 /** 56 * Given a map of known constant variable values, substitute them in for references to those 57 * variables occurring in this expression and its subexpressions. Similar simplifications, such 58 * as folding a constant binary expression down to a single value, may also be performed. 59 * Returns a new expression which replaces this expression, or null if no replacements were 60 * made. If a new expression is returned, this expression is no longer valid. 61 */ 62 virtual std::unique_ptr<Expression> constantPropagate(const IRGenerator& irGenerator, 63 const DefinitionMap& definitions) { 64 return nullptr; 65 } 66 67 const Kind fKind; 68 const Type& fType; 69 70 typedef IRNode INHERITED; 71 }; 72 73 } // namespace 74 75 #endif 76
