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/*
* Copyright 2020 Google LLC
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SKSL_CONSTANT_FOLDER
#define SKSL_CONSTANT_FOLDER
#include <memory>
#include "include/private/SkSLDefines.h"
#include "include/sksl/SkSLOperator.h"
namespace SkSL {
class Context;
class Expression;
class Position;
class Type;
/**
* Performs constant folding on IR expressions. This simplifies expressions containing
* compile-time constants, such as replacing `Literal(2) + Literal(2)` with `Literal(4)`.
*/
class ConstantFolder {
public:
/**
* If value is an int literal or const int variable with a known value, returns true and stores
* the value in out. Otherwise returns false.
*/
static bool GetConstantInt(const Expression& value, SKSL_INT* out);
/**
* If value is a literal or const scalar variable with a known value, returns true and stores
* the value in out. Otherwise returns false.
*/
static bool GetConstantValue(const Expression& value, double* out);
/**
* If the expression is a const variable with a known compile-time-constant value, returns that
* value. If not, returns the original expression as-is.
*/
static const Expression* GetConstantValueForVariable(const Expression& value);
/**
* If the expression is a const variable with a known compile-time-constant value, returns that
* value. If not, returns null.
*/
static const Expression* GetConstantValueOrNullForVariable(const Expression& value);
/**
* If the expression is a const variable with a known compile-time-constant value, returns a
* clone of that value. If not, returns the original expression as-is.
*/
static std::unique_ptr<Expression> MakeConstantValueForVariable(Position pos,
std::unique_ptr<Expression> expr);
/** Simplifies the binary expression `left OP right`. Returns null if it can't be simplified. */
static std::unique_ptr<Expression> Simplify(const Context& context,
Position pos,
const Expression& left,
Operator op,
const Expression& right,
const Type& resultType);
};
} // namespace SkSL
#endif // SKSL_CONSTANT_FOLDER
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