Revert of Reland: Remove register index/code indirection

src/lithium-allocator.cc

 // Copyright 2012 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/lithium-allocator.h"
 
 #include "src/hydrogen.h"
 #include "src/lithium-inl.h"
 #include "src/lithium-allocator-inl.h"
-#include "src/register-configuration.h"
 #include "src/string-stream.h"
 
 namespace v8 {
 namespace internal {
 
 static inline LifetimePosition Min(LifetimePosition a, LifetimePosition b) {
   return a.Value() < b.Value() ? a : b;
 }
 
 
@@ skipping 558 matching lines @@
   while (!iterator.Done()) {
     int operand_index = iterator.Current();
     LiveRange* range = LiveRangeFor(operand_index);
     range->AddUseInterval(start, end, zone());
     iterator.Advance();
   }
 }
 
 
 int LAllocator::FixedDoubleLiveRangeID(int index) {
-  return -index - 1 - Register::kNumRegisters;
+  return -index - 1 - Register::kMaxNumAllocatableRegisters;
 }
 
 
 LOperand* LAllocator::AllocateFixed(LUnallocated* operand,
                                     int pos,
                                     bool is_tagged) {
   TraceAlloc("Allocating fixed reg for op %d\n", operand->virtual_register());
   DCHECK(operand->HasFixedPolicy());
   if (operand->HasFixedSlotPolicy()) {
     operand->ConvertTo(LOperand::STACK_SLOT, operand->fixed_slot_index());
@@ skipping 11 matching lines @@
     LInstruction* instr = InstructionAt(pos);
     if (instr->HasPointerMap()) {
       instr->pointer_map()->RecordPointer(operand, chunk()->zone());
     }
   }
   return operand;
 }
 
 
 LiveRange* LAllocator::FixedLiveRangeFor(int index) {
-  DCHECK(index < Register::kNumRegisters);
+  DCHECK(index < Register::kMaxNumAllocatableRegisters);
   LiveRange* result = fixed_live_ranges_[index];
   if (result == NULL) {
     result = new(zone()) LiveRange(FixedLiveRangeID(index), chunk()->zone());
     DCHECK(result->IsFixed());
     result->kind_ = GENERAL_REGISTERS;
     SetLiveRangeAssignedRegister(result, index);
     fixed_live_ranges_[index] = result;
   }
   return result;
 }
 
 
 LiveRange* LAllocator::FixedDoubleLiveRangeFor(int index) {
-  DCHECK(index < DoubleRegister::kMaxNumRegisters);
+  DCHECK(index < DoubleRegister::NumAllocatableRegisters());
   LiveRange* result = fixed_double_live_ranges_[index];
   if (result == NULL) {
     result = new(zone()) LiveRange(FixedDoubleLiveRangeID(index),
                                    chunk()->zone());
     DCHECK(result->IsFixed());
     result->kind_ = DOUBLE_REGISTERS;
     SetLiveRangeAssignedRegister(result, index);
     fixed_double_live_ranges_[index] = result;
   }
   return result;
@@ skipping 287 matching lines @@
       if (instr != NULL) {
         LOperand* output = instr->Output();
         if (output != NULL) {
           if (output->IsUnallocated()) {
             live->Remove(LUnallocated::cast(output)->virtual_register());
           }
           Define(curr_position, output, NULL);
         }
 
         if (instr->ClobbersRegisters()) {
-          for (int i = 0; i < Register::kNumRegisters; ++i) {
-            if (Register::from_code(i).IsAllocatable()) {
-              if (output == NULL || !output->IsRegister() ||
-                  output->index() != i) {
-                LiveRange* range = FixedLiveRangeFor(i);
-                range->AddUseInterval(curr_position,
-                                      curr_position.InstructionEnd(), zone());
-              }
+          for (int i = 0; i < Register::kMaxNumAllocatableRegisters; ++i) {
+            if (output == NULL || !output->IsRegister() ||
+                output->index() != i) {
+              LiveRange* range = FixedLiveRangeFor(i);
+              range->AddUseInterval(curr_position,
+                                    curr_position.InstructionEnd(),
+                                    zone());
             }
           }
         }
 
         if (instr->ClobbersDoubleRegisters(isolate())) {
-          for (int i = 0; i < DoubleRegister::kMaxNumRegisters; ++i) {
-            if (DoubleRegister::from_code(i).IsAllocatable()) {
-              if (output == NULL || !output->IsDoubleRegister() ||
-                  output->index() != i) {
-                LiveRange* range = FixedDoubleLiveRangeFor(i);
-                range->AddUseInterval(curr_position,
-                                      curr_position.InstructionEnd(), zone());
-              }
+          for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); ++i) {
+            if (output == NULL || !output->IsDoubleRegister() ||
+                output->index() != i) {
+              LiveRange* range = FixedDoubleLiveRangeFor(i);
+              range->AddUseInterval(curr_position,
+                                    curr_position.InstructionEnd(),
+                                    zone());
             }
           }
         }
 
         for (UseIterator it(instr); !it.Done(); it.Advance()) {
           LOperand* input = it.Current();
 
           LifetimePosition use_pos;
           if (input->IsUnallocated() &&
               LUnallocated::cast(input)->IsUsedAtStart()) {
@@ skipping 91 matching lines @@
         AddMove(phi_operand, live_range->GetSpillOperand(), chunk()->zone());
     live_range->SetSpillStartIndex(phi->block()->first_instruction_index());
   }
 }
 
 
 bool LAllocator::Allocate(LChunk* chunk) {
   DCHECK(chunk_ == NULL);
   chunk_ = static_cast<LPlatformChunk*>(chunk);
   assigned_registers_ =
-      new (chunk->zone()) BitVector(Register::kNumRegisters, chunk->zone());
-  assigned_double_registers_ = new (chunk->zone())
-      BitVector(DoubleRegister::kMaxNumRegisters, chunk->zone());
+      new(chunk->zone()) BitVector(Register::NumAllocatableRegisters(),
+                                   chunk->zone());
+  assigned_double_registers_ =
+      new(chunk->zone()) BitVector(DoubleRegister::NumAllocatableRegisters(),
+                                   chunk->zone());
   MeetRegisterConstraints();
   if (!AllocationOk()) return false;
   ResolvePhis();
   BuildLiveRanges();
   AllocateGeneralRegisters();
   if (!AllocationOk()) return false;
   AllocateDoubleRegisters();
   if (!AllocationOk()) return false;
   PopulatePointerMaps();
   ConnectRanges();
@@ skipping 366 matching lines @@
         DCHECK(!operand->IsStackSlot());
         map->RecordPointer(operand, chunk()->zone());
       }
     }
   }
 }
 
 
 void LAllocator::AllocateGeneralRegisters() {
   LAllocatorPhase phase("L_Allocate general registers", this);
-  num_registers_ =
-      RegisterConfiguration::ArchDefault()->num_allocatable_general_registers();
-  allocatable_register_codes_ =
-      RegisterConfiguration::ArchDefault()->allocatable_general_codes();
+  num_registers_ = Register::NumAllocatableRegisters();
   mode_ = GENERAL_REGISTERS;
   AllocateRegisters();
 }
 
 
 void LAllocator::AllocateDoubleRegisters() {
   LAllocatorPhase phase("L_Allocate double registers", this);
-  num_registers_ =
-      RegisterConfiguration::ArchDefault()->num_allocatable_double_registers();
-  allocatable_register_codes_ =
-      RegisterConfiguration::ArchDefault()->allocatable_double_codes();
+  num_registers_ = DoubleRegister::NumAllocatableRegisters();
   mode_ = DOUBLE_REGISTERS;
   AllocateRegisters();
 }
 
 
 void LAllocator::AllocateRegisters() {
   DCHECK(unhandled_live_ranges_.is_empty());
 
   for (int i = 0; i < live_ranges_.length(); ++i) {
     if (live_ranges_[i] != NULL) {
       if (live_ranges_[i]->Kind() == mode_) {
         AddToUnhandledUnsorted(live_ranges_[i]);
       }
     }
   }
   SortUnhandled();
   DCHECK(UnhandledIsSorted());
 
   DCHECK(reusable_slots_.is_empty());
   DCHECK(active_live_ranges_.is_empty());
   DCHECK(inactive_live_ranges_.is_empty());
 
   if (mode_ == DOUBLE_REGISTERS) {
-    for (int i = 0; i < fixed_double_live_ranges_.length(); ++i) {
+    for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); ++i) {
       LiveRange* current = fixed_double_live_ranges_.at(i);
       if (current != NULL) {
         AddToInactive(current);
       }
     }
   } else {
     DCHECK(mode_ == GENERAL_REGISTERS);
     for (int i = 0; i < fixed_live_ranges_.length(); ++i) {
       LiveRange* current = fixed_live_ranges_.at(i);
       if (current != NULL) {
@@ skipping 73 matching lines @@
   }
 
   reusable_slots_.Rewind(0);
   active_live_ranges_.Rewind(0);
   inactive_live_ranges_.Rewind(0);
 }
 
 
 const char* LAllocator::RegisterName(int allocation_index) {
   if (mode_ == GENERAL_REGISTERS) {
-    return Register::from_code(allocation_index).ToString();
+    return Register::AllocationIndexToString(allocation_index);
   } else {
-    return DoubleRegister::from_code(allocation_index).ToString();
+    return DoubleRegister::AllocationIndexToString(allocation_index);
   }
 }
 
 
 void LAllocator::TraceAlloc(const char* msg, ...) {
   if (FLAG_trace_alloc) {
     va_list arguments;
     va_start(arguments, msg);
     base::OS::VPrint(msg, arguments);
     va_end(arguments);
@@ skipping 141 matching lines @@
 
 
 void LAllocator::InactiveToActive(LiveRange* range) {
   DCHECK(inactive_live_ranges_.Contains(range));
   inactive_live_ranges_.RemoveElement(range);
   active_live_ranges_.Add(range, zone());
   TraceAlloc("Moving live range %d from inactive to active\n", range->id());
 }
 
 
+// TryAllocateFreeReg and AllocateBlockedReg assume this
+// when allocating local arrays.
+STATIC_ASSERT(DoubleRegister::kMaxNumAllocatableRegisters >=
+              Register::kMaxNumAllocatableRegisters);
+
+
 bool LAllocator::TryAllocateFreeReg(LiveRange* current) {
-  DCHECK(DoubleRegister::kMaxNumRegisters >= Register::kNumRegisters);
+  LifetimePosition free_until_pos[DoubleRegister::kMaxNumAllocatableRegisters];
 
-  LifetimePosition free_until_pos[DoubleRegister::kMaxNumRegisters];
-
-  for (int i = 0; i < DoubleRegister::kMaxNumRegisters; i++) {
+  for (int i = 0; i < num_registers_; i++) {
     free_until_pos[i] = LifetimePosition::MaxPosition();
   }
 
   for (int i = 0; i < active_live_ranges_.length(); ++i) {
     LiveRange* cur_active = active_live_ranges_.at(i);
     free_until_pos[cur_active->assigned_register()] =
         LifetimePosition::FromInstructionIndex(0);
   }
 
   for (int i = 0; i < inactive_live_ranges_.length(); ++i) {
@@ skipping 20 matching lines @@
     if (free_until_pos[register_index].Value() >= current->End().Value()) {
       TraceAlloc("Assigning preferred reg %s to live range %d\n",
                  RegisterName(register_index),
                  current->id());
       SetLiveRangeAssignedRegister(current, register_index);
       return true;
     }
   }
 
   // Find the register which stays free for the longest time.
-  int reg = allocatable_register_codes_[0];
+  int reg = 0;
   for (int i = 1; i < RegisterCount(); ++i) {
-    int code = allocatable_register_codes_[i];
-    if (free_until_pos[code].Value() > free_until_pos[reg].Value()) {
-      reg = code;
+    if (free_until_pos[i].Value() > free_until_pos[reg].Value()) {
+      reg = i;
     }
   }
 
   LifetimePosition pos = free_until_pos[reg];
 
   if (pos.Value() <= current->Start().Value()) {
     // All registers are blocked.
     return false;
   }
 
@@ skipping 21 matching lines @@
 void LAllocator::AllocateBlockedReg(LiveRange* current) {
   UsePosition* register_use = current->NextRegisterPosition(current->Start());
   if (register_use == NULL) {
     // There is no use in the current live range that requires a register.
     // We can just spill it.
     Spill(current);
     return;
   }
 
 
-  LifetimePosition use_pos[DoubleRegister::kMaxNumRegisters];
-  LifetimePosition block_pos[DoubleRegister::kMaxNumRegisters];
+  LifetimePosition use_pos[DoubleRegister::kMaxNumAllocatableRegisters];
+  LifetimePosition block_pos[DoubleRegister::kMaxNumAllocatableRegisters];
 
-  for (int i = 0; i < DoubleRegister::kMaxNumRegisters; i++) {
+  for (int i = 0; i < num_registers_; i++) {
     use_pos[i] = block_pos[i] = LifetimePosition::MaxPosition();
   }
 
   for (int i = 0; i < active_live_ranges_.length(); ++i) {
     LiveRange* range = active_live_ranges_[i];
     int cur_reg = range->assigned_register();
     if (range->IsFixed() || !range->CanBeSpilled(current->Start())) {
       block_pos[cur_reg] = use_pos[cur_reg] =
           LifetimePosition::FromInstructionIndex(0);
     } else {
@@ skipping 14 matching lines @@
     if (!next_intersection.IsValid()) continue;
     int cur_reg = range->assigned_register();
     if (range->IsFixed()) {
       block_pos[cur_reg] = Min(block_pos[cur_reg], next_intersection);
       use_pos[cur_reg] = Min(block_pos[cur_reg], use_pos[cur_reg]);
     } else {
       use_pos[cur_reg] = Min(use_pos[cur_reg], next_intersection);
     }
   }
 
-  int reg = allocatable_register_codes_[0];
+  int reg = 0;
   for (int i = 1; i < RegisterCount(); ++i) {
-    int code = allocatable_register_codes_[i];
-    if (use_pos[code].Value() > use_pos[reg].Value()) {
-      reg = code;
+    if (use_pos[i].Value() > use_pos[reg].Value()) {
+      reg = i;
     }
   }
 
   LifetimePosition pos = use_pos[reg];
 
   if (pos.Value() < register_use->pos().Value()) {
     // All registers are blocked before the first use that requires a register.
     // Spill starting part of live range up to that use.
     SpillBetween(current, current->Start(), register_use->pos());
     return;
@@ skipping 280 matching lines @@
   }
 
 #ifdef DEBUG
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 
 }  // namespace internal
 }  // namespace v8