michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef jit_StupidAllocator_h
michael@0: #define jit_StupidAllocator_h
michael@0: 
michael@0: #include "jit/RegisterAllocator.h"
michael@0: 
michael@0: // Simple register allocator that only carries registers within basic blocks.
michael@0: 
michael@0: namespace js {
michael@0: namespace jit {
michael@0: 
michael@0: class StupidAllocator : public RegisterAllocator
michael@0: {
michael@0:     static const uint32_t MAX_REGISTERS = Registers::Allocatable + FloatRegisters::Allocatable;
michael@0:     static const uint32_t MISSING_ALLOCATION = UINT32_MAX;
michael@0: 
michael@0:     struct AllocatedRegister {
michael@0:         AnyRegister reg;
michael@0: 
michael@0:         // The type of the value in the register.
michael@0:         LDefinition::Type type;
michael@0: 
michael@0:         // Virtual register this physical reg backs, or MISSING_ALLOCATION.
michael@0:         uint32_t vreg;
michael@0: 
michael@0:         // id of the instruction which most recently used this register.
michael@0:         uint32_t age;
michael@0: 
michael@0:         // Whether the physical register is not synced with the backing stack slot.
michael@0:         bool dirty;
michael@0: 
michael@0:         void set(uint32_t vreg, LInstruction *ins = nullptr, bool dirty = false) {
michael@0:             this->vreg = vreg;
michael@0:             this->age = ins ? ins->id() : 0;
michael@0:             this->dirty = dirty;
michael@0:         }
michael@0:     };
michael@0: 
michael@0:     // Active allocation for the current code position.
michael@0:     mozilla::Array<AllocatedRegister, MAX_REGISTERS> registers;
michael@0:     uint32_t registerCount;
michael@0: 
michael@0:     // Type indicating an index into registers.
michael@0:     typedef uint32_t RegisterIndex;
michael@0: 
michael@0:     // Information about each virtual register.
michael@0:     Vector<LDefinition*, 0, SystemAllocPolicy> virtualRegisters;
michael@0: 
michael@0:   public:
michael@0:     StupidAllocator(MIRGenerator *mir, LIRGenerator *lir, LIRGraph &graph)
michael@0:       : RegisterAllocator(mir, lir, graph)
michael@0:     {
michael@0:     }
michael@0: 
michael@0:     bool go();
michael@0: 
michael@0:   private:
michael@0:     bool init();
michael@0: 
michael@0:     void syncForBlockEnd(LBlock *block, LInstruction *ins);
michael@0:     void allocateForInstruction(LInstruction *ins);
michael@0:     void allocateForDefinition(LInstruction *ins, LDefinition *def);
michael@0: 
michael@0:     LAllocation *stackLocation(uint32_t vreg);
michael@0: 
michael@0:     RegisterIndex registerIndex(AnyRegister reg);
michael@0: 
michael@0:     AnyRegister ensureHasRegister(LInstruction *ins, uint32_t vreg);
michael@0:     RegisterIndex allocateRegister(LInstruction *ins, uint32_t vreg);
michael@0: 
michael@0:     void syncRegister(LInstruction *ins, RegisterIndex index);
michael@0:     void evictRegister(LInstruction *ins, RegisterIndex index);
michael@0:     void loadRegister(LInstruction *ins, uint32_t vreg, RegisterIndex index, LDefinition::Type type);
michael@0: 
michael@0:     RegisterIndex findExistingRegister(uint32_t vreg);
michael@0: 
michael@0:     bool allocationRequiresRegister(const LAllocation *alloc, AnyRegister reg);
michael@0:     bool registerIsReserved(LInstruction *ins, AnyRegister reg);
michael@0: };
michael@0: 
michael@0: } // namespace jit
michael@0: } // namespace js
michael@0: 
michael@0: #endif /* jit_StupidAllocator_h */