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_PREFIXEXPRESSION 9 #define SKSL_PREFIXEXPRESSION 10 11 #include "SkSLExpression.h" 12 #include "SkSLFloatLiteral.h" 13 #include "SkSLIRGenerator.h" 14 #include "SkSLToken.h" 15 16 namespace SkSL { 17 18 /** 19 * An expression modified by a unary operator appearing before it, such as '!flag'. 20 */ 21 struct PrefixExpression : public Expression { 22 PrefixExpression(Token::Kind op, std::unique_ptr<Expression> operand) 23 : INHERITED(operand->fPosition, kPrefix_Kind, operand->fType) 24 , fOperand(std::move(operand)) 25 , fOperator(op) {} 26 27 bool isConstant() const override { 28 return fOperator == Token::MINUS && fOperand->isConstant(); 29 } 30 31 bool hasSideEffects() const override { 32 return fOperator == Token::PLUSPLUS || fOperator == Token::MINUSMINUS || 33 fOperand->hasSideEffects(); 34 } 35 36 std::unique_ptr<Expression> constantPropagate(const IRGenerator& irGenerator, 37 const DefinitionMap& definitions) override { 38 if (fOperand->fKind == Expression::kFloatLiteral_Kind) { 39 return std::unique_ptr<Expression>(new FloatLiteral( 40 irGenerator.fContext, 41 Position(), 42 -((FloatLiteral&) *fOperand).fValue)); 43 44 } 45 return nullptr; 46 } 47 48 String description() const override { 49 return Token::OperatorName(fOperator) + fOperand->description(); 50 } 51 52 std::unique_ptr<Expression> fOperand; 53 const Token::Kind fOperator; 54 55 typedef Expression INHERITED; 56 }; 57 58 } // namespace 59 60 #endif 61
