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fb449b9ea5
will soon be renamed) into their own file. The new file should not emit DEBUG output or have other side effects. The LiveInterval class also now doesn't know whether its working on registers or some other thing. In the future we will want to use the LiveInterval class and friends to do stack packing. In addition to a code simplification, this will allow us to do it more easily. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15134 91177308-0d34-0410-b5e6-96231b3b80d8
110 lines
3.7 KiB
C++
110 lines
3.7 KiB
C++
//===-- llvm/CodeGen/LiveInterval.h - Interval representation ---*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the LiveRange and LiveInterval classes. Given some
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// numbering of each the machine instructions an interval [i, j) is said to be a
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// live interval for register v if there is no instruction with number j' > j
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// such that v is live at j' abd there is no instruction with number i' < i such
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// that v is live at i'. In this implementation intervals can have holes,
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// i.e. an interval might look like [1,20), [50,65), [1000,1001). Each
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// individual range is represented as an instance of LiveRange, and the whole
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// interval is represented as an instance of LiveInterval.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CODEGEN_LIVEINTERVAL_H
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#define LLVM_CODEGEN_LIVEINTERVAL_H
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#include <iosfwd>
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#include <vector>
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#include <cassert>
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namespace llvm {
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/// LiveRange structure - This represents a simple register range in the
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/// program, with an inclusive start point and an exclusive end point.
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/// These ranges are rendered as [start,end).
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struct LiveRange {
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unsigned start; // Start point of the interval (inclusive)
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unsigned end; // End point of the interval (exclusive)
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LiveRange(unsigned S, unsigned E) : start(S), end(E) {
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assert(S < E && "Cannot create empty or backwards range");
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}
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bool operator<(const LiveRange &LR) const {
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return start < LR.start || (start == LR.start && end < LR.end);
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}
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bool operator==(const LiveRange &LR) const {
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return start == LR.start && end == LR.end;
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}
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private:
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LiveRange(); // DO NOT IMPLEMENT
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};
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std::ostream& operator<<(std::ostream& os, const LiveRange &LR);
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/// LiveInterval - This class represents some number of live ranges for a
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/// register or value. This class also contains a bit of register allocator
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/// state.
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struct LiveInterval {
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typedef std::vector<LiveRange> Ranges;
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unsigned reg; // the register of this interval
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float weight; // weight of this interval
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Ranges ranges; // the ranges in which this register is live
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bool isDefinedOnce; // True if this interval contains one value.
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LiveInterval(unsigned Reg, float Weight)
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: reg(Reg), weight(Weight), isDefinedOnce(false) {
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}
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bool containsOneValue() const { return isDefinedOnce; }
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bool empty() const { return ranges.empty(); }
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/// start - Return the lowest numbered slot covered by interval.
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unsigned start() const {
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assert(!empty() && "empty interval for register");
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return ranges.front().start;
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}
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/// end - return the maximum point of the interval of the whole,
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/// exclusive.
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unsigned end() const {
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assert(!empty() && "empty interval for register");
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return ranges.back().end;
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}
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bool expiredAt(unsigned index) const {
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return end() <= (index + 1);
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}
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bool liveAt(unsigned index) const;
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bool overlaps(const LiveInterval& other) const;
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void addRange(LiveRange R);
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void join(const LiveInterval& other);
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bool operator<(const LiveInterval& other) const {
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return start() < other.start();
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}
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bool operator==(const LiveInterval& other) const {
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return reg == other.reg;
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}
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private:
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Ranges::iterator mergeRangesForward(Ranges::iterator it);
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Ranges::iterator mergeRangesBackward(Ranges::iterator it);
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};
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std::ostream& operator<<(std::ostream& os, const LiveInterval& li);
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}
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#endif
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