[turbofan] Unit tests for live range conflicts.

src/compiler/greedy-allocator.cc

 // 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/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 GreedyAllocator::kAllocatedRangeMultiplier = 10.0;
+
+
 namespace {
 
 
 void UpdateOperands(LiveRange* range, RegisterAllocationData* data) {
   int reg_id = range->assigned_register();
   range->SetUseHints(reg_id);
   if (range->is_phi()) {
     data->GetPhiMapValueFor(range->id())->set_assigned_register(reg_id);
   }
 }
@@ skipping 96 matching lines @@
       allocations_(local_zone),
       scheduler_(local_zone) {}
 
 
 void GreedyAllocator::AssignRangeToRegister(int reg_id, LiveRange* range) {
   TRACE("Assigning register %s to live range %d\n", RegisterName(reg_id),
         range->id());
 
   DCHECK(!range->HasRegisterAssigned());
 
-  current_allocations(reg_id)->AllocateRange(range);
+  AllocateRegisterToRange(reg_id, range);
 
   TRACE("Assigning %s to range %d\n", RegisterName(reg_id), range->id());
   range->set_assigned_register(reg_id);
-
-  DCHECK(current_allocations(reg_id)->VerifyAllocationsAreValid());
 }
 
 
 void GreedyAllocator::PreallocateFixedRanges() {
   allocations_.resize(num_registers());
   for (int i = 0; i < num_registers(); i++) {
     allocations_[i] = new (local_zone()) CoalescedLiveRanges(local_zone());
   }
 
   for (LiveRange* fixed_range : GetFixedRegisters()) {
     if (fixed_range != nullptr) {
       DCHECK_EQ(mode(), fixed_range->kind());
       DCHECK(fixed_range->IsFixed());
 
       int reg_nr = fixed_range->assigned_register();
       EnsureValidRangeWeight(fixed_range);
-      current_allocations(reg_nr)->AllocateRange(fixed_range);
+      AllocateRegisterToRange(reg_nr, fixed_range);
     }
   }
 }
 
 
 void GreedyAllocator::ScheduleAllocationCandidates() {
   for (auto range : data()->live_ranges()) {
     if (CanProcessRange(range) && !range->spilled()) {
       scheduler().Schedule(range);
     }
@@ skipping 16 matching lines @@
   int evictable_reg = -1;
   EnsureValidRangeWeight(range);
   DCHECK(range->weight() != LiveRange::kInvalidWeight);
 
   float smallest_weight = LiveRange::kMaxWeight;
 
   // Seek either the first free register, or, from the set of registers
   // where the maximum conflict is lower than the candidate's weight, the one
   // with the smallest such weight.
   for (int i = 0; i < num_registers(); i++) {
-    float max_conflict_weight =
-        current_allocations(i)->GetMaximumConflictingWeight(range);
+    float max_conflict_weight = GetMaximumConflictingWeight(i, range);
     if (max_conflict_weight == LiveRange::kInvalidWeight) {
       free_reg = i;
       break;
     }
     if (max_conflict_weight < range->weight() &&
         max_conflict_weight < smallest_weight) {
       smallest_weight = max_conflict_weight;
       evictable_reg = i;
     }
   }
 
   // We have a free register, so we use it.
   if (free_reg >= 0) {
     TRACE("Found free register %s for live range %d\n", RegisterName(free_reg),
           range->id());
     AssignRangeToRegister(free_reg, range);
     return;
   }
 
   // We found a register to perform evictions, so we evict and allocate our
   // candidate.
   if (evictable_reg >= 0) {
     TRACE("Found evictable register %s for live range %d\n",
           RegisterName(free_reg), range->id());
-    current_allocations(evictable_reg)
-        ->EvictAndRescheduleConflicts(range, &scheduler());
+    EvictAndRescheduleConflicts(evictable_reg, range);
     AssignRangeToRegister(evictable_reg, range);
     return;
   }
 
   // The range needs to be split or spilled.
   SplitOrSpillBlockedRange(range);
 }
 
 
+void GreedyAllocator::EvictAndRescheduleConflicts(unsigned reg_id,
+                                                  const LiveRange* range) {
+  auto conflicts = current_allocations(reg_id)->GetConflicts(range);
+  for (LiveRange* conflict = conflicts.Current(); conflict != nullptr;
+       conflict = conflicts.RemoveCurrentAndGetNext()) {
+    DCHECK(conflict->HasRegisterAssigned());
+    CHECK(!conflict->IsFixed());
+    conflict->UnsetAssignedRegister();
+    UpdateWeightAtEviction(conflict);
+    scheduler().Schedule(conflict);
+    TRACE("Evicted range %d.\n", conflict->id());
+  }
+}
+
+
 void GreedyAllocator::SplitAndSpillRangesDefinedByMemoryOperand() {
   size_t initial_range_count = data()->live_ranges().size();
   for (size_t i = 0; i < initial_range_count; ++i) {
     auto range = data()->live_ranges()[i];
     if (!CanProcessRange(range)) continue;
     if (range->HasNoSpillType()) continue;
 
     LifetimePosition start = range->Start();
     TRACE("Live range %d is defined by a spill operand.\n", range->id());
     auto next_pos = start;
@@ skipping 51 matching lines @@
       data()->MarkAllocated(mode(), static_cast<int>(i));
     }
   }
   allocations_.clear();
 
   TRACE("End allocating function %s with the Greedy Allocator\n",
         data()->debug_name());
 }
 
 
+float GreedyAllocator::GetMaximumConflictingWeight(
+    unsigned reg_id, const LiveRange* range) const {
+  float ret = LiveRange::kInvalidWeight;
+
+  auto conflicts = current_allocations(reg_id)->GetConflicts(range);
+  for (LiveRange* conflict = conflicts.Current(); conflict != nullptr;
+       conflict = conflicts.GetNext()) {
+    DCHECK_NE(conflict->weight(), LiveRange::kInvalidWeight);
+    ret = Max(ret, conflict->weight());
+    if (ret == LiveRange::kMaxWeight) return ret;
+  }
+
+  return ret;
+}
+
+
 void GreedyAllocator::EnsureValidRangeWeight(LiveRange* range) {
   // The live range weight will be invalidated when ranges are created or split.
   // Otherwise, it is consistently updated when the range is allocated or
   // unallocated.
   if (range->weight() != LiveRange::kInvalidWeight) return;
 
   if (range->IsFixed()) {
     range->set_weight(LiveRange::kMaxWeight);
     return;
   }
@@ skipping 30 matching lines @@
     scheduler().Schedule(range);
     return;
   }
   SpillRangeAsLastResort(range);
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8