lib/CodeGen/PhysRegTracker.h

   1 //===-- llvm/CodeGen/PhysRegTracker.h - Physical Register Tracker -*- C++ -*-=//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements a physical register tracker. The tracker
  11 // tracks physical register usage through addRegUse and
  12 // delRegUse. isRegAvail checks if a physical register is available or
  13 // not taking into consideration register aliases.
  14 //
  15 //===----------------------------------------------------------------------===//
  16
  17 #ifndef LLVM_CODEGEN_PHYSREGTRACKER_H
  18 #define LLVM_CODEGEN_PHYSREGTRACKER_H
  19
  20 #include "llvm/Target/TargetRegisterInfo.h"
  21
  22 namespace llvm {
  23
  24     class PhysRegTracker {
  25         const TargetRegisterInfo* tri_;
  26         std::vector<unsigned> regUse_;
  27
  28     public:
  29         explicit PhysRegTracker(const TargetRegisterInfo& tri)
  30             : tri_(&tri),
  31               regUse_(tri_->getNumRegs(), 0) {
  32         }
  33
  34         PhysRegTracker(const PhysRegTracker& rhs)
  35             : tri_(rhs.tri_),
  36               regUse_(rhs.regUse_) {
  37         }
  38
  39         const PhysRegTracker& operator=(const PhysRegTracker& rhs) {
  40             tri_ = rhs.tri_;
  41             regUse_ = rhs.regUse_;
  42             return *this;
  43         }
  44
  45         void addRegUse(unsigned physReg) {
  46             assert(TargetRegisterInfo::isPhysicalRegister(physReg) &&
  47                    "should be physical register!");
  48             ++regUse_[physReg];
  49             for (const unsigned* as = tri_->getAliasSet(physReg); *as; ++as)
  50                 ++regUse_[*as];
  51         }
  52
  53         void delRegUse(unsigned physReg) {
  54             assert(TargetRegisterInfo::isPhysicalRegister(physReg) &&
  55                    "should be physical register!");
  56             assert(regUse_[physReg] != 0);
  57             --regUse_[physReg];
  58             for (const unsigned* as = tri_->getAliasSet(physReg); *as; ++as) {
  59                 assert(regUse_[*as] != 0);
  60                 --regUse_[*as];
  61             }
  62         }
  63
  64         bool isRegAvail(unsigned physReg) const {
  65             assert(TargetRegisterInfo::isPhysicalRegister(physReg) &&
  66                    "should be physical register!");
  67             return regUse_[physReg] == 0;
  68         }
  69     };
  70
  71 } // End llvm namespace
  72
  73 #endif