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/*
* Copyright (C) 2015 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef B3HeapRange_h
#define B3HeapRange_h
#if ENABLE(B3_JIT)
#include <limits.h>
#include <wtf/MathExtras.h>
#include <wtf/PrintStream.h>
namespace JSC { namespace B3 {
// Alias analysis in B3 is done by checking if two integer ranges overlap. This is powerful enough
// to be used for TBAA-style alias analysis used by the DFG, FTL, and LLVM: you just turn each node
// in the tree of abstract heaps into a pre/post range.
//
// Note that the 'begin' is inclusive, while the 'end' is exclusive. These two ranges are non-
// overlapping:
//
// rangeA = 0...8
// rangeB = 8...16
class HeapRange {
public:
typedef unsigned Type;
HeapRange()
: m_begin(0)
, m_end(0)
{
}
explicit HeapRange(unsigned value)
: m_begin(value)
, m_end(value + 1)
{
ASSERT(m_end >= m_begin);
}
HeapRange(unsigned begin, unsigned end)
: m_begin(begin)
, m_end(end)
{
ASSERT(m_end >= m_begin);
if (m_begin == m_end) {
// Canonicalize empty ranges.
m_begin = 0;
m_end = 0;
}
}
static HeapRange top()
{
return HeapRange(0, UINT_MAX);
}
bool operator==(const HeapRange& other) const
{
return m_begin == other.m_begin
&& m_end == other.m_end;
}
bool operator!=(const HeapRange& other) const
{
return !(*this == other);
}
explicit operator bool() const { return m_begin != m_end; }
unsigned begin() const { return m_begin; }
unsigned end() const { return m_end; }
bool overlaps(const HeapRange& other) const
{
return WTF::rangesOverlap(m_begin, m_end, other.m_begin, other.m_end);
}
void dump(PrintStream& out) const;
private:
unsigned m_begin;
unsigned m_end;
};
} } // namespace JSC::B3
#endif // ENABLE(B3_JIT)
#endif // B3HeapRange_h
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