1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
// 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 {
#define TRACE(...) \
do { \
if (FLAG_trace_alloc) PrintF(__VA_ARGS__); \
} while (false)
const float CoalescedLiveRanges::kAllocatedRangeMultiplier = 10.0;
void CoalescedLiveRanges::AllocateRange(LiveRange* range) {
UpdateWeightAtAllocation(range);
for (auto interval = range->first_interval(); interval != nullptr;
interval = interval->next()) {
storage().insert({interval->start(), interval->end(), range});
}
}
void CoalescedLiveRanges::Remove(LiveRange* range) {
for (auto interval = range->first_interval(); interval != nullptr;
interval = interval->next()) {
storage().erase({interval->start(), interval->end(), nullptr});
}
range->UnsetAssignedRegister();
}
float CoalescedLiveRanges::GetMaximumConflictingWeight(
const LiveRange* range) const {
float ret = LiveRange::kInvalidWeight;
auto end = storage().end();
for (auto query = range->first_interval(); query != nullptr;
query = query->next()) {
auto conflict = GetFirstConflict(query);
if (conflict == end) continue;
for (; QueryIntersectsAllocatedInterval(query, conflict); ++conflict) {
// It is possible we'll visit the same range multiple times, because
// successive (not necessarily consecutive) intervals belong to the same
// range, or because different intervals of the query range have the same
// range as conflict.
DCHECK_NE(conflict->range->weight(), LiveRange::kInvalidWeight);
ret = Max(ret, conflict->range->weight());
if (ret == LiveRange::kMaxWeight) break;
}
}
return ret;
}
void CoalescedLiveRanges::EvictAndRescheduleConflicts(
LiveRange* range, AllocationScheduler* scheduler) {
auto end = storage().end();
for (auto query = range->first_interval(); query != nullptr;
query = query->next()) {
auto conflict = GetFirstConflict(query);
if (conflict == end) continue;
while (QueryIntersectsAllocatedInterval(query, conflict)) {
LiveRange* range_to_evict = conflict->range;
// Bypass successive intervals belonging to the same range, because we're
// about to remove this range, and we don't want the storage iterator to
// become invalid.
while (conflict != end && conflict->range == range_to_evict) {
++conflict;
}
DCHECK(range_to_evict->HasRegisterAssigned());
CHECK(!range_to_evict->IsFixed());
Remove(range_to_evict);
UpdateWeightAtEviction(range_to_evict);
TRACE("Evicted range %d.\n", range_to_evict->id());
scheduler->Schedule(range_to_evict);
}
}
}
bool CoalescedLiveRanges::VerifyAllocationsAreValid() const {
LifetimePosition last_end = LifetimePosition::GapFromInstructionIndex(0);
for (auto i : storage_) {
if (i.start < last_end) {
return false;
}
last_end = i.end;
}
return true;
}
void CoalescedLiveRanges::UpdateWeightAtAllocation(LiveRange* range) {
DCHECK_NE(range->weight(), LiveRange::kInvalidWeight);
range->set_weight(range->weight() * kAllocatedRangeMultiplier);
}
void CoalescedLiveRanges::UpdateWeightAtEviction(LiveRange* range) {
DCHECK_NE(range->weight(), LiveRange::kInvalidWeight);
range->set_weight(range->weight() / kAllocatedRangeMultiplier);
}
CoalescedLiveRanges::interval_iterator CoalescedLiveRanges::GetFirstConflict(
const UseInterval* query) const {
DCHECK(query != nullptr);
auto end = storage().end();
LifetimePosition q_start = query->start();
LifetimePosition q_end = query->end();
if (storage().empty() || storage().rbegin()->end <= q_start ||
storage().begin()->start >= q_end) {
return end;
}
auto ret = storage().upper_bound(AsAllocatedInterval(q_start));
// ret 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 (ret != storage().begin()) {
--ret;
if (!QueryIntersectsAllocatedInterval(query, ret)) {
// The interval behind wasn't intersecting, so move back.
++ret;
}
}
if (ret != end && QueryIntersectsAllocatedInterval(query, ret)) return ret;
return end;
}
} // namespace compiler
} // namespace internal
} // namespace v8
|
