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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#ifndef frontend_ValueUsage_h
#define frontend_ValueUsage_h
namespace js {
namespace frontend {
// Used to control whether the expression result is used. This enables various
// optimizations, for example it allows to emit JSOp::CallIgnoresRv for function
// calls.
enum class ValueUsage {
// Assume the value of the current expression may be used. This is always
// correct but prohibits optimizations like JSOp::CallIgnoresRv.
WantValue,
// Pass this when emitting an expression if the expression's value is
// definitely unused by later instructions. You must make sure the next
// instruction is JSOp::Pop, a jump to a JSOp::Pop, or something similar.
IgnoreValue
};
} /* namespace frontend */
} /* namespace js */
#endif /* frontend_ValueUsage_h */