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// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/compiler/coalesced-live-ranges.h"
#include "src/compiler/greedy-allocator.h"
#include "src/compiler/register-allocator.h"
namespace v8 {
namespace internal {
namespace compiler {
LiveRangeConflictIterator::LiveRangeConflictIterator(const LiveRange* range,
IntervalStore* storage)
: query_(range->first_interval()),
pos_(storage->end()),
intervals_(storage) {
MovePosAndQueryToFirstConflict();
}
LiveRange* LiveRangeConflictIterator::Current() const {
if (IsFinished()) return nullptr;
return pos_->range_;
}
void LiveRangeConflictIterator::MovePosToFirstConflictForQuery() {
DCHECK(query_ != nullptr);
auto end = intervals_->end();
LifetimePosition q_start = query_->start();
LifetimePosition q_end = query_->end();
if (intervals_->empty() || intervals_->rbegin()->end_ <= q_start ||
intervals_->begin()->start_ >= q_end) {
pos_ = end;
return;
}
pos_ = intervals_->upper_bound(AsAllocatedInterval(q_start));
// pos is either at the end (no start strictly greater than q_start) or
// at some position with the aforementioned property. In either case, the
// allocated interval before this one may intersect our query:
// either because, although it starts before this query's start, it ends
// after; or because it starts exactly at the query start. So unless we're
// right at the beginning of the storage - meaning the first allocated
// interval is also starting after this query's start - see what's behind.
if (pos_ != intervals_->begin()) {
--pos_;
if (!QueryIntersectsAllocatedInterval()) {
// The interval behind wasn't intersecting, so move back.
++pos_;
}
}
if (pos_ == end || !QueryIntersectsAllocatedInterval()) {
pos_ = end;
}
}
void LiveRangeConflictIterator::MovePosAndQueryToFirstConflict() {
auto end = intervals_->end();
for (; query_ != nullptr; query_ = query_->next()) {
MovePosToFirstConflictForQuery();
if (pos_ != end) {
DCHECK(QueryIntersectsAllocatedInterval());
return;
}
}
Invalidate();
}
void LiveRangeConflictIterator::IncrementPosAndSkipOverRepetitions() {
auto end = intervals_->end();
DCHECK(pos_ != end);
LiveRange* current_conflict = Current();
while (pos_ != end && pos_->range_ == current_conflict) {
++pos_;
}
}
LiveRange* LiveRangeConflictIterator::InternalGetNext(bool clean_behind) {
if (IsFinished()) return nullptr;
LiveRange* to_clear = Current();
IncrementPosAndSkipOverRepetitions();
// At this point, pos_ is either at the end, or on an interval that doesn't
// correspond to the same range as to_clear. This interval may not even be
// a conflict.
if (clean_behind) {
// Since we parked pos_ on an iterator that won't be affected by removal,
// we can safely delete to_clear's intervals.
for (auto interval = to_clear->first_interval(); interval != nullptr;
interval = interval->next()) {
AllocatedInterval erase_key(interval->start(), interval->end(), nullptr);
intervals_->erase(erase_key);
}
}
// We may have parked pos_ at the end, or on a non-conflict. In that case,
// move to the next query and reinitialize pos and query. This may invalidate
// the iterator, if no more conflicts are available.
if (!QueryIntersectsAllocatedInterval()) {
query_ = query_->next();
MovePosAndQueryToFirstConflict();
}
return Current();
}
LiveRangeConflictIterator CoalescedLiveRanges::GetConflicts(
const LiveRange* range) {
return LiveRangeConflictIterator(range, &intervals());
}
void CoalescedLiveRanges::AllocateRange(LiveRange* range) {
for (auto interval = range->first_interval(); interval != nullptr;
interval = interval->next()) {
AllocatedInterval to_insert(interval->start(), interval->end(), range);
intervals().insert(to_insert);
}
}
bool CoalescedLiveRanges::VerifyAllocationsAreValidForTesting() const {
LifetimePosition last_end = LifetimePosition::GapFromInstructionIndex(0);
for (auto i : intervals_) {
if (i.start_ < last_end) {
return false;
}
last_end = i.end_;
}
return true;
}
} // namespace compiler
} // namespace internal
} // namespace v8
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