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Turn on -Wunused and -Wno-unused-parameter. Clean up most of the resulting fall out by removing unused variables. Remaining warnings have to do with unused functions (I didn't want to delete code without review) and unused variables in generated code. Maintainers should clean up the remaining issues when they see them. All changes pass DejaGnu tests and Olden. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31380 91177308-0d34-0410-b5e6-96231b3b80d8
513 lines
17 KiB
C++
513 lines
17 KiB
C++
//===-- LiveInterval.cpp - Live Interval Representation -------------------===//
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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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#include "llvm/CodeGen/LiveInterval.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Target/MRegisterInfo.h"
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#include <algorithm>
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#include <iostream>
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#include <map>
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using namespace llvm;
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// An example for liveAt():
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//
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// this = [1,4), liveAt(0) will return false. The instruction defining this
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// spans slots [0,3]. The interval belongs to an spilled definition of the
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// variable it represents. This is because slot 1 is used (def slot) and spans
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// up to slot 3 (store slot).
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//
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bool LiveInterval::liveAt(unsigned I) const {
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Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I);
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if (r == ranges.begin())
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return false;
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--r;
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return r->contains(I);
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}
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// overlaps - Return true if the intersection of the two live intervals is
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// not empty.
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//
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// An example for overlaps():
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//
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// 0: A = ...
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// 4: B = ...
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// 8: C = A + B ;; last use of A
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//
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// The live intervals should look like:
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//
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// A = [3, 11)
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// B = [7, x)
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// C = [11, y)
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//
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// A->overlaps(C) should return false since we want to be able to join
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// A and C.
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//
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bool LiveInterval::overlapsFrom(const LiveInterval& other,
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const_iterator StartPos) const {
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const_iterator i = begin();
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const_iterator ie = end();
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const_iterator j = StartPos;
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const_iterator je = other.end();
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assert((StartPos->start <= i->start || StartPos == other.begin()) &&
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StartPos != other.end() && "Bogus start position hint!");
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if (i->start < j->start) {
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i = std::upper_bound(i, ie, j->start);
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if (i != ranges.begin()) --i;
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} else if (j->start < i->start) {
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++StartPos;
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if (StartPos != other.end() && StartPos->start <= i->start) {
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assert(StartPos < other.end() && i < end());
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j = std::upper_bound(j, je, i->start);
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if (j != other.ranges.begin()) --j;
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}
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} else {
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return true;
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}
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if (j == je) return false;
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while (i != ie) {
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if (i->start > j->start) {
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std::swap(i, j);
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std::swap(ie, je);
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}
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if (i->end > j->start)
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return true;
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++i;
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}
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return false;
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}
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/// extendIntervalEndTo - This method is used when we want to extend the range
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/// specified by I to end at the specified endpoint. To do this, we should
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/// merge and eliminate all ranges that this will overlap with. The iterator is
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/// not invalidated.
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void LiveInterval::extendIntervalEndTo(Ranges::iterator I, unsigned NewEnd) {
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assert(I != ranges.end() && "Not a valid interval!");
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unsigned ValId = I->ValId;
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// Search for the first interval that we can't merge with.
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Ranges::iterator MergeTo = next(I);
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for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo) {
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assert(MergeTo->ValId == ValId && "Cannot merge with differing values!");
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}
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// If NewEnd was in the middle of an interval, make sure to get its endpoint.
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I->end = std::max(NewEnd, prior(MergeTo)->end);
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// Erase any dead ranges.
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ranges.erase(next(I), MergeTo);
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// If the newly formed range now touches the range after it and if they have
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// the same value number, merge the two ranges into one range.
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Ranges::iterator Next = next(I);
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if (Next != ranges.end() && Next->start <= I->end && Next->ValId == ValId) {
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I->end = Next->end;
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ranges.erase(Next);
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}
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}
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/// extendIntervalStartTo - This method is used when we want to extend the range
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/// specified by I to start at the specified endpoint. To do this, we should
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/// merge and eliminate all ranges that this will overlap with.
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LiveInterval::Ranges::iterator
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LiveInterval::extendIntervalStartTo(Ranges::iterator I, unsigned NewStart) {
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assert(I != ranges.end() && "Not a valid interval!");
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unsigned ValId = I->ValId;
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// Search for the first interval that we can't merge with.
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Ranges::iterator MergeTo = I;
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do {
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if (MergeTo == ranges.begin()) {
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I->start = NewStart;
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ranges.erase(MergeTo, I);
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return I;
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}
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assert(MergeTo->ValId == ValId && "Cannot merge with differing values!");
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--MergeTo;
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} while (NewStart <= MergeTo->start);
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// If we start in the middle of another interval, just delete a range and
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// extend that interval.
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if (MergeTo->end >= NewStart && MergeTo->ValId == ValId) {
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MergeTo->end = I->end;
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} else {
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// Otherwise, extend the interval right after.
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++MergeTo;
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MergeTo->start = NewStart;
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MergeTo->end = I->end;
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}
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ranges.erase(next(MergeTo), next(I));
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return MergeTo;
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}
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LiveInterval::iterator
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LiveInterval::addRangeFrom(LiveRange LR, iterator From) {
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unsigned Start = LR.start, End = LR.end;
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iterator it = std::upper_bound(From, ranges.end(), Start);
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// If the inserted interval starts in the middle or right at the end of
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// another interval, just extend that interval to contain the range of LR.
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if (it != ranges.begin()) {
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iterator B = prior(it);
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if (LR.ValId == B->ValId) {
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if (B->start <= Start && B->end >= Start) {
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extendIntervalEndTo(B, End);
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return B;
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}
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} else {
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// Check to make sure that we are not overlapping two live ranges with
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// different ValId's.
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assert(B->end <= Start &&
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"Cannot overlap two LiveRanges with differing ValID's"
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" (did you def the same reg twice in a MachineInstr?)");
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}
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}
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// Otherwise, if this range ends in the middle of, or right next to, another
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// interval, merge it into that interval.
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if (it != ranges.end())
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if (LR.ValId == it->ValId) {
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if (it->start <= End) {
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it = extendIntervalStartTo(it, Start);
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// If LR is a complete superset of an interval, we may need to grow its
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// endpoint as well.
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if (End > it->end)
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extendIntervalEndTo(it, End);
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return it;
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}
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} else {
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// Check to make sure that we are not overlapping two live ranges with
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// different ValId's.
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assert(it->start >= End &&
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"Cannot overlap two LiveRanges with differing ValID's");
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}
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// Otherwise, this is just a new range that doesn't interact with anything.
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// Insert it.
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return ranges.insert(it, LR);
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}
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/// removeRange - Remove the specified range from this interval. Note that
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/// the range must already be in this interval in its entirety.
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void LiveInterval::removeRange(unsigned Start, unsigned End) {
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// Find the LiveRange containing this span.
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Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start);
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assert(I != ranges.begin() && "Range is not in interval!");
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--I;
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assert(I->contains(Start) && I->contains(End-1) &&
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"Range is not entirely in interval!");
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// If the span we are removing is at the start of the LiveRange, adjust it.
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if (I->start == Start) {
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if (I->end == End)
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ranges.erase(I); // Removed the whole LiveRange.
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else
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I->start = End;
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return;
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}
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// Otherwise if the span we are removing is at the end of the LiveRange,
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// adjust the other way.
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if (I->end == End) {
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I->end = Start;
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return;
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}
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// Otherwise, we are splitting the LiveRange into two pieces.
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unsigned OldEnd = I->end;
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I->end = Start; // Trim the old interval.
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// Insert the new one.
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ranges.insert(next(I), LiveRange(End, OldEnd, I->ValId));
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}
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/// getLiveRangeContaining - Return the live range that contains the
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/// specified index, or null if there is none.
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LiveInterval::const_iterator
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LiveInterval::FindLiveRangeContaining(unsigned Idx) const {
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const_iterator It = std::upper_bound(begin(), end(), Idx);
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if (It != ranges.begin()) {
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--It;
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if (It->contains(Idx))
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return It;
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}
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return end();
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}
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LiveInterval::iterator
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LiveInterval::FindLiveRangeContaining(unsigned Idx) {
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iterator It = std::upper_bound(begin(), end(), Idx);
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if (It != begin()) {
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--It;
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if (It->contains(Idx))
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return It;
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}
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return end();
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}
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/// join - Join two live intervals (this, and other) together. This applies
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/// mappings to the value numbers in the LHS/RHS intervals as specified. If
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/// the intervals are not joinable, this aborts.
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void LiveInterval::join(LiveInterval &Other, int *LHSValNoAssignments,
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int *RHSValNoAssignments,
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SmallVector<std::pair<unsigned,
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unsigned>, 16> &NewValueNumberInfo) {
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// Try to do the least amount of work possible. In particular, if there are
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// more liverange chunks in the other set than there are in the 'this' set,
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// swap sets to merge the fewest chunks in possible.
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//
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// Also, if one range is a physreg and one is a vreg, we always merge from the
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// vreg into the physreg, which leaves the vreg intervals pristine.
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if ((Other.ranges.size() > ranges.size() &&
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MRegisterInfo::isVirtualRegister(reg)) ||
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MRegisterInfo::isPhysicalRegister(Other.reg)) {
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swap(Other);
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std::swap(LHSValNoAssignments, RHSValNoAssignments);
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}
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// Determine if any of our live range values are mapped. This is uncommon, so
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// we want to avoid the interval scan if not.
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bool MustMapCurValNos = false;
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for (unsigned i = 0, e = getNumValNums(); i != e; ++i) {
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if (ValueNumberInfo[i].first == ~2U) continue; // tombstone value #
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if (i != (unsigned)LHSValNoAssignments[i]) {
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MustMapCurValNos = true;
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break;
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}
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}
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// If we have to apply a mapping to our base interval assignment, rewrite it
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// now.
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if (MustMapCurValNos) {
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// Map the first live range.
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iterator OutIt = begin();
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OutIt->ValId = LHSValNoAssignments[OutIt->ValId];
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++OutIt;
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for (iterator I = OutIt, E = end(); I != E; ++I) {
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OutIt->ValId = LHSValNoAssignments[I->ValId];
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// If this live range has the same value # as its immediate predecessor,
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// and if they are neighbors, remove one LiveRange. This happens when we
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// have [0,3:0)[4,7:1) and map 0/1 onto the same value #.
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if (OutIt->ValId == (OutIt-1)->ValId && (OutIt-1)->end == OutIt->start) {
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(OutIt-1)->end = OutIt->end;
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} else {
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if (I != OutIt) {
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OutIt->start = I->start;
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OutIt->end = I->end;
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}
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// Didn't merge, on to the next one.
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++OutIt;
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}
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}
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// If we merge some live ranges, chop off the end.
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ranges.erase(OutIt, end());
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}
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// Okay, now insert the RHS live ranges into the LHS.
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iterator InsertPos = begin();
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for (iterator I = Other.begin(), E = Other.end(); I != E; ++I) {
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// Map the ValId in the other live range to the current live range.
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I->ValId = RHSValNoAssignments[I->ValId];
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InsertPos = addRangeFrom(*I, InsertPos);
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}
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ValueNumberInfo.clear();
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ValueNumberInfo.append(NewValueNumberInfo.begin(), NewValueNumberInfo.end());
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weight += Other.weight;
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}
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/// MergeRangesInAsValue - Merge all of the intervals in RHS into this live
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/// interval as the specified value number. The LiveRanges in RHS are
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/// allowed to overlap with LiveRanges in the current interval, but only if
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/// the overlapping LiveRanges have the specified value number.
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void LiveInterval::MergeRangesInAsValue(const LiveInterval &RHS,
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unsigned LHSValNo) {
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// TODO: Make this more efficient.
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iterator InsertPos = begin();
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for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) {
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// Map the ValId in the other live range to the current live range.
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LiveRange Tmp = *I;
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Tmp.ValId = LHSValNo;
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InsertPos = addRangeFrom(Tmp, InsertPos);
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}
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}
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/// MergeInClobberRanges - For any live ranges that are not defined in the
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/// current interval, but are defined in the Clobbers interval, mark them
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/// used with an unknown definition value.
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void LiveInterval::MergeInClobberRanges(const LiveInterval &Clobbers) {
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if (Clobbers.begin() == Clobbers.end()) return;
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// Find a value # to use for the clobber ranges. If there is already a value#
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// for unknown values, use it.
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// FIXME: Use a single sentinal number for these!
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unsigned ClobberValNo = getNextValue(~0U, 0);
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iterator IP = begin();
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for (const_iterator I = Clobbers.begin(), E = Clobbers.end(); I != E; ++I) {
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unsigned Start = I->start, End = I->end;
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IP = std::upper_bound(IP, end(), Start);
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// If the start of this range overlaps with an existing liverange, trim it.
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if (IP != begin() && IP[-1].end > Start) {
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Start = IP[-1].end;
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// Trimmed away the whole range?
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if (Start >= End) continue;
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}
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// If the end of this range overlaps with an existing liverange, trim it.
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if (IP != end() && End > IP->start) {
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End = IP->start;
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// If this trimmed away the whole range, ignore it.
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if (Start == End) continue;
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}
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// Insert the clobber interval.
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IP = addRangeFrom(LiveRange(Start, End, ClobberValNo), IP);
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}
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}
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/// MergeValueNumberInto - This method is called when two value nubmers
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/// are found to be equivalent. This eliminates V1, replacing all
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/// LiveRanges with the V1 value number with the V2 value number. This can
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/// cause merging of V1/V2 values numbers and compaction of the value space.
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void LiveInterval::MergeValueNumberInto(unsigned V1, unsigned V2) {
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assert(V1 != V2 && "Identical value#'s are always equivalent!");
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// This code actually merges the (numerically) larger value number into the
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// smaller value number, which is likely to allow us to compactify the value
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// space. The only thing we have to be careful of is to preserve the
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// instruction that defines the result value.
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// Make sure V2 is smaller than V1.
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if (V1 < V2) {
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setValueNumberInfo(V1, getValNumInfo(V2));
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std::swap(V1, V2);
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}
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// Merge V1 live ranges into V2.
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for (iterator I = begin(); I != end(); ) {
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iterator LR = I++;
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if (LR->ValId != V1) continue; // Not a V1 LiveRange.
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// Okay, we found a V1 live range. If it had a previous, touching, V2 live
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// range, extend it.
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if (LR != begin()) {
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iterator Prev = LR-1;
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if (Prev->ValId == V2 && Prev->end == LR->start) {
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Prev->end = LR->end;
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// Erase this live-range.
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ranges.erase(LR);
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I = Prev+1;
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LR = Prev;
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}
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}
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// Okay, now we have a V1 or V2 live range that is maximally merged forward.
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// Ensure that it is a V2 live-range.
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LR->ValId = V2;
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// If we can merge it into later V2 live ranges, do so now. We ignore any
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// following V1 live ranges, as they will be merged in subsequent iterations
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// of the loop.
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if (I != end()) {
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if (I->start == LR->end && I->ValId == V2) {
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LR->end = I->end;
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ranges.erase(I);
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I = LR+1;
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}
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}
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}
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// Now that V1 is dead, remove it. If it is the largest value number, just
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// nuke it (and any other deleted values neighboring it), otherwise mark it as
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// ~1U so it can be nuked later.
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if (V1 == getNumValNums()-1) {
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do {
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ValueNumberInfo.pop_back();
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} while (ValueNumberInfo.back().first == ~1U);
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} else {
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ValueNumberInfo[V1].first = ~1U;
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}
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}
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std::ostream& llvm::operator<<(std::ostream& os, const LiveRange &LR) {
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return os << '[' << LR.start << ',' << LR.end << ':' << LR.ValId << ")";
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}
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void LiveRange::dump() const {
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std::cerr << *this << "\n";
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}
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void LiveInterval::print(std::ostream &OS, const MRegisterInfo *MRI) const {
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if (MRI && MRegisterInfo::isPhysicalRegister(reg))
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OS << MRI->getName(reg);
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else
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OS << "%reg" << reg;
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OS << ',' << weight;
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if (empty())
|
|
OS << "EMPTY";
|
|
else {
|
|
OS << " = ";
|
|
for (LiveInterval::Ranges::const_iterator I = ranges.begin(),
|
|
E = ranges.end(); I != E; ++I)
|
|
OS << *I;
|
|
}
|
|
|
|
// Print value number info.
|
|
if (getNumValNums()) {
|
|
OS << " ";
|
|
for (unsigned i = 0; i != getNumValNums(); ++i) {
|
|
if (i) OS << " ";
|
|
OS << i << "@";
|
|
if (ValueNumberInfo[i].first == ~0U) {
|
|
OS << "?";
|
|
} else {
|
|
OS << ValueNumberInfo[i].first;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void LiveInterval::dump() const {
|
|
std::cerr << *this << "\n";
|
|
}
|