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_VARIABLEREFERENCE 9 #define SKSL_VARIABLEREFERENCE 10 11 #include "src/sksl/ir/SkSLExpression.h" 12 13 namespace SkSL { 14 15 class IRGenerator; 16 class Variable; 17 18 enum class VariableRefKind : int8_t { 19 kRead, 20 kWrite, 21 kReadWrite, 22 // taking the address of a variable - we consider this a read & write but don't complain if 23 // the variable was not previously assigned 24 kPointer 25 }; 26 27 /** 28 * A reference to a variable, through which it can be read or written. In the statement: 29 * 30 * x = x + 1; 31 * 32 * there is only one Variable 'x', but two VariableReferences to it. 33 */ 34 class VariableReference final : public Expression { 35 public: 36 using RefKind = VariableRefKind; 37 38 static constexpr Kind kExpressionKind = Kind::kVariableReference; 39 40 VariableReference(int offset, const Variable* variable, RefKind refKind); 41 42 // Creates a VariableReference. There isn't much in the way of error-checking or optimization 43 // opportunities here. 44 static std::unique_ptr<Expression> Make(int offset, 45 const Variable* variable, 46 RefKind refKind = RefKind::kRead) { 47 SkASSERT(variable); 48 return std::make_unique<VariableReference>(offset, variable, refKind); 49 } 50 51 VariableReference(const VariableReference&) = delete; 52 VariableReference& operator=(const VariableReference&) = delete; 53 variable()54 const Variable* variable() const { 55 return fVariable; 56 } 57 refKind()58 RefKind refKind() const { 59 return fRefKind; 60 } 61 62 void setRefKind(RefKind refKind); 63 void setVariable(const Variable* variable); 64 65 bool hasProperty(Property property) const override; 66 67 bool isConstantOrUniform() const override; 68 clone()69 std::unique_ptr<Expression> clone() const override { 70 return std::make_unique<VariableReference>(fOffset, this->variable(), this->refKind()); 71 } 72 73 String description() const override; 74 75 private: 76 const Variable* fVariable; 77 VariableRefKind fRefKind; 78 79 using INHERITED = Expression; 80 }; 81 82 } // namespace SkSL 83 84 #endif 85