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      1 // WebAssemblyMachineFunctionInfo.h-WebAssembly machine function info-*- 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 /// \file
     11 /// \brief This file declares WebAssembly-specific per-machine-function
     12 /// information.
     13 ///
     14 //===----------------------------------------------------------------------===//
     15 
     16 #ifndef LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYMACHINEFUNCTIONINFO_H
     17 #define LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYMACHINEFUNCTIONINFO_H
     18 
     19 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
     20 #include "llvm/CodeGen/MachineRegisterInfo.h"
     21 
     22 namespace llvm {
     23 
     24 /// This class is derived from MachineFunctionInfo and contains private
     25 /// WebAssembly-specific information for each MachineFunction.
     26 class WebAssemblyFunctionInfo final : public MachineFunctionInfo {
     27   MachineFunction &MF;
     28 
     29   std::vector<MVT> Params;
     30 
     31   /// A mapping from CodeGen vreg index to WebAssembly register number.
     32   std::vector<unsigned> WARegs;
     33 
     34   /// A mapping from CodeGen vreg index to a boolean value indicating whether
     35   /// the given register is considered to be "stackified", meaning it has been
     36   /// determined or made to meet the stack requirements:
     37   ///   - single use (per path)
     38   ///   - single def (per path)
     39   ///   - defined and used in LIFO order with other stack registers
     40   BitVector VRegStackified;
     41 
     42   // One entry for each possible target reg. we expect it to be small.
     43   std::vector<unsigned> PhysRegs;
     44 
     45 public:
     46   explicit WebAssemblyFunctionInfo(MachineFunction &MF) : MF(MF) {
     47     PhysRegs.resize(WebAssembly::NUM_TARGET_REGS, -1U);
     48   }
     49   ~WebAssemblyFunctionInfo() override;
     50 
     51   void addParam(MVT VT) { Params.push_back(VT); }
     52   const std::vector<MVT> &getParams() const { return Params; }
     53 
     54   static const unsigned UnusedReg = -1u;
     55 
     56   void stackifyVReg(unsigned VReg) {
     57     if (TargetRegisterInfo::virtReg2Index(VReg) >= VRegStackified.size())
     58       VRegStackified.resize(TargetRegisterInfo::virtReg2Index(VReg) + 1);
     59     VRegStackified.set(TargetRegisterInfo::virtReg2Index(VReg));
     60   }
     61   bool isVRegStackified(unsigned VReg) const {
     62     if (TargetRegisterInfo::virtReg2Index(VReg) >= VRegStackified.size())
     63       return false;
     64     return VRegStackified.test(TargetRegisterInfo::virtReg2Index(VReg));
     65   }
     66 
     67   void initWARegs();
     68   void setWAReg(unsigned VReg, unsigned WAReg) {
     69     assert(WAReg != UnusedReg);
     70     assert(TargetRegisterInfo::virtReg2Index(VReg) < WARegs.size());
     71     WARegs[TargetRegisterInfo::virtReg2Index(VReg)] = WAReg;
     72   }
     73   unsigned getWAReg(unsigned Reg) const {
     74     if (TargetRegisterInfo::isVirtualRegister(Reg)) {
     75       assert(TargetRegisterInfo::virtReg2Index(Reg) < WARegs.size());
     76       return WARegs[TargetRegisterInfo::virtReg2Index(Reg)];
     77     }
     78     return PhysRegs[Reg];
     79   }
     80   // If new virtual registers are created after initWARegs has been called,
     81   // this function can be used to add WebAssembly register mappings for them.
     82   void addWAReg(unsigned VReg, unsigned WAReg) {
     83     assert(VReg = WARegs.size());
     84     WARegs.push_back(WAReg);
     85   }
     86 
     87   void addPReg(unsigned PReg, unsigned WAReg) {
     88     assert(PReg < WebAssembly::NUM_TARGET_REGS);
     89     assert(WAReg < -1U);
     90     PhysRegs[PReg] = WAReg;
     91   }
     92   const std::vector<unsigned> &getPhysRegs() const { return PhysRegs; }
     93 };
     94 
     95 } // end namespace llvm
     96 
     97 #endif
     98