Subzero: Refactor some common TargetLowering initializations.

src/IceTargetLoweringMIPS32.cpp

 //===- subzero/src/IceTargetLoweringMIPS32.cpp - MIPS32 lowering ----------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 23 matching lines @@
 
 using llvm::isInt;
 
 namespace {
 
 // The maximum number of arguments to pass in GPR registers.
 constexpr uint32_t MIPS32_MAX_GPR_ARG = 4;
 
 } // end of anonymous namespace
 
-TargetMIPS32::TargetMIPS32(Cfg *Func) : TargetLowering(Func) {
-  // TODO: Don't initialize IntegerRegisters and friends every time. Instead,
-  // initialize in some sort of static initializer for the class.
+TargetMIPS32::TargetMIPS32(Cfg *Func) : TargetLowering(Func) {}
 
+void TargetMIPS32::staticInit() {
   llvm::SmallBitVector IntegerRegisters(RegMIPS32::Reg_NUM);
   llvm::SmallBitVector I64PairRegisters(RegMIPS32::Reg_NUM);
   llvm::SmallBitVector Float32Registers(RegMIPS32::Reg_NUM);
   llvm::SmallBitVector Float64Registers(RegMIPS32::Reg_NUM);
   llvm::SmallBitVector VectorRegisters(RegMIPS32::Reg_NUM);
   llvm::SmallBitVector InvalidRegisters(RegMIPS32::Reg_NUM);
   ScratchRegs.resize(RegMIPS32::Reg_NUM);
 #define X(val, encode, name, scratch, preserved, stackptr, frameptr, isInt,    \
           isI64Pair, isFP32, isFP64, isVec128, alias_init)                     \
   IntegerRegisters[RegMIPS32::val] = isInt;                                    \
@@ skipping 990 matching lines @@
 TargetHeaderMIPS32::TargetHeaderMIPS32(GlobalContext *Ctx)
     : TargetHeaderLowering(Ctx) {}
 
 void TargetHeaderMIPS32::lower() {
   OstreamLocker L(Ctx);
   Ostream &Str = Ctx->getStrEmit();
   Str << "\t.set\tnomicromips\n";
   Str << "\t.set\tnomips16\n";
 }
 
+llvm::SmallBitVector TargetMIPS32::TypeToRegisterSet[IceType_NUM];
+llvm::SmallBitVector TargetMIPS32::RegisterAliases[RegMIPS32::Reg_NUM];
+llvm::SmallBitVector TargetMIPS32::ScratchRegs;
+
 } // end of namespace Ice