Line data    Source code

       1             : // Copyright 2015 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #ifndef V8_INTERPRETER_BYTECODE_REGISTER_ALLOCATOR_H_
       6             : #define V8_INTERPRETER_BYTECODE_REGISTER_ALLOCATOR_H_
       7             : 
       8             : #include "src/interpreter/bytecode-register.h"
       9             : #include "src/interpreter/bytecodes.h"
      10             : #include "src/zone/zone-containers.h"
      11             : 
      12             : namespace v8 {
      13             : namespace internal {
      14             : namespace interpreter {
      15             : 
      16             : // A class that allows the allocation of contiguous temporary registers.
      17             : class BytecodeRegisterAllocator final {
      18             :  public:
      19             :   // Enables observation of register allocation and free events.
      20     2104165 :   class Observer {
      21             :    public:
      22           0 :     virtual ~Observer() {}
      23             :     virtual void RegisterAllocateEvent(Register reg) = 0;
      24             :     virtual void RegisterListAllocateEvent(RegisterList reg_list) = 0;
      25             :     virtual void RegisterListFreeEvent(RegisterList reg_list) = 0;
      26             :   };
      27             : 
      28             :   explicit BytecodeRegisterAllocator(int start_index)
      29             :       : next_register_index_(start_index),
      30             :         max_register_count_(start_index),
      31     2104900 :         observer_(nullptr) {}
      32             :   ~BytecodeRegisterAllocator() {}
      33             : 
      34             :   // Returns a new register.
      35    19436585 :   Register NewRegister() {
      36    19436585 :     Register reg(next_register_index_++);
      37    38873170 :     max_register_count_ = std::max(next_register_index_, max_register_count_);
      38    19436585 :     if (observer_) {
      39    19433607 :       observer_->RegisterAllocateEvent(reg);
      40             :     }
      41    19436585 :     return reg;
      42             :   }
      43             : 
      44             :   // Returns a consecutive list of |count| new registers.
      45      413628 :   RegisterList NewRegisterList(int count) {
      46      413628 :     RegisterList reg_list(next_register_index_, count);
      47      413628 :     next_register_index_ += count;
      48      827256 :     max_register_count_ = std::max(next_register_index_, max_register_count_);
      49      413628 :     if (observer_) {
      50      413229 :       observer_->RegisterListAllocateEvent(reg_list);
      51             :     }
      52      413628 :     return reg_list;
      53             :   }
      54             : 
      55             :   // Returns a growable register list.
      56             :   RegisterList NewGrowableRegisterList() {
      57             :     RegisterList reg_list(next_register_index_, 0);
      58             :     return reg_list;
      59             :   }
      60             : 
      61             :   // Appends a new register to |reg_list| increasing it's count by one and
      62             :   // returning the register added.
      63             :   //
      64             :   // Note: no other new registers must be currently allocated since the register
      65             :   // list was originally allocated.
      66     9010909 :   Register GrowRegisterList(RegisterList* reg_list) {
      67     9010909 :     Register reg(NewRegister());
      68             :     reg_list->IncrementRegisterCount();
      69             :     // If the following CHECK fails then a register was allocated (and not
      70             :     // freed) between the creation of the RegisterList and this call to add a
      71             :     // Register.
      72     9010906 :     CHECK_EQ(reg.index(), reg_list->last_register().index());
      73     9010906 :     return reg;
      74             :   }
      75             : 
      76             :   // Release all registers above |register_index|.
      77             :   void ReleaseRegisters(int register_index) {
      78    74677532 :     if (observer_) {
      79             :       observer_->RegisterListFreeEvent(
      80   149322062 :           RegisterList(register_index, next_register_index_ - register_index));
      81             :     }
      82    74677509 :     next_register_index_ = register_index;
      83             :   }
      84             : 
      85             :   // Returns true if the register |reg| is a live register.
      86             :   bool RegisterIsLive(Register reg) const {
      87           0 :     return reg.index() < next_register_index_;
      88             :   }
      89             : 
      90     2104165 :   void set_observer(Observer* observer) { observer_ = observer; }
      91             : 
      92             :   int next_register_index() const { return next_register_index_; }
      93             :   int maximum_register_count() const { return max_register_count_; }
      94             : 
      95             :  private:
      96             :   int next_register_index_;
      97             :   int max_register_count_;
      98             :   Observer* observer_;
      99             : 
     100             :   DISALLOW_COPY_AND_ASSIGN(BytecodeRegisterAllocator);
     101             : };
     102             : 
     103             : }  // namespace interpreter
     104             : }  // namespace internal
     105             : }  // namespace v8
     106             : 
     107             : 
     108             : #endif  // V8_INTERPRETER_BYTECODE_REGISTER_ALLOCATOR_H_