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/*
* 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_VARIABLEREFERENCE
#define SKSL_VARIABLEREFERENCE
#include "src/sksl/ir/SkSLExpression.h"
namespace SkSL {
class IRGenerator;
/**
* A reference to a variable, through which it can be read or written. In the statement:
*
* x = x + 1;
*
* there is only one Variable 'x', but two VariableReferences to it.
*/
struct VariableReference : public Expression {
enum RefKind {
kRead_RefKind,
kWrite_RefKind,
kReadWrite_RefKind,
// taking the address of a variable - we consider this a read & write but don't complain if
// the variable was not previously assigned
kPointer_RefKind
};
VariableReference(int offset, const Variable& variable, RefKind refKind = kRead_RefKind);
~VariableReference() override;
VariableReference(const VariableReference&) = delete;
VariableReference& operator=(const VariableReference&) = delete;
RefKind refKind() const {
return fRefKind;
}
void setRefKind(RefKind refKind);
bool hasProperty(Property property) const override {
switch (property) {
case Property::kSideEffects: return false;
case Property::kContainsRTAdjust: return fVariable.fName == "sk_RTAdjust";
default:
SkASSERT(false);
return false;
}
}
bool isConstant() const override {
return 0 != (fVariable.fModifiers.fFlags & Modifiers::kConst_Flag);
}
bool isConstantOrUniform() const override {
return (fVariable.fModifiers.fFlags & Modifiers::kUniform_Flag) != 0;
}
int nodeCount() const override {
return 1;
}
std::unique_ptr<Expression> clone() const override {
return std::unique_ptr<Expression>(new VariableReference(fOffset, fVariable, fRefKind));
}
String description() const override {
return fVariable.fName;
}
static std::unique_ptr<Expression> copy_constant(const IRGenerator& irGenerator,
const Expression* expr);
std::unique_ptr<Expression> constantPropagate(const IRGenerator& irGenerator,
const DefinitionMap& definitions) override;
const Variable& fVariable;
RefKind fRefKind;
private:
typedef Expression INHERITED;
};
} // namespace
#endif