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      1 //===-- Target.cpp ----------------------------------------------*- C++ -*-===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 #include "../Target.h"
      9 #include "AArch64.h"
     10 #include "AArch64RegisterInfo.h"
     11 
     12 namespace llvm {
     13 namespace exegesis {
     14 
     15 static unsigned getLoadImmediateOpcode(unsigned RegBitWidth) {
     16   switch (RegBitWidth) {
     17   case 32:
     18     return AArch64::MOVi32imm;
     19   case 64:
     20     return AArch64::MOVi64imm;
     21   }
     22   llvm_unreachable("Invalid Value Width");
     23 }
     24 
     25 // Generates instruction to load an immediate value into a register.
     26 static MCInst loadImmediate(unsigned Reg, unsigned RegBitWidth,
     27                             const APInt &Value) {
     28   if (Value.getBitWidth() > RegBitWidth)
     29     llvm_unreachable("Value must fit in the Register");
     30   return MCInstBuilder(getLoadImmediateOpcode(RegBitWidth))
     31       .addReg(Reg)
     32       .addImm(Value.getZExtValue());
     33 }
     34 
     35 #include "AArch64GenExegesis.inc"
     36 
     37 namespace {
     38 
     39 class ExegesisAArch64Target : public ExegesisTarget {
     40 public:
     41   ExegesisAArch64Target() : ExegesisTarget(AArch64CpuPfmCounters) {}
     42 
     43 private:
     44   std::vector<MCInst> setRegTo(const MCSubtargetInfo &STI, unsigned Reg,
     45                                const APInt &Value) const override {
     46     if (AArch64::GPR32RegClass.contains(Reg))
     47       return {loadImmediate(Reg, 32, Value)};
     48     if (AArch64::GPR64RegClass.contains(Reg))
     49       return {loadImmediate(Reg, 64, Value)};
     50     errs() << "setRegTo is not implemented, results will be unreliable\n";
     51     return {};
     52   }
     53 
     54   bool matchesArch(Triple::ArchType Arch) const override {
     55     return Arch == Triple::aarch64 || Arch == Triple::aarch64_be;
     56   }
     57 
     58   void addTargetSpecificPasses(PassManagerBase &PM) const override {
     59     // Function return is a pseudo-instruction that needs to be expanded
     60     PM.add(createAArch64ExpandPseudoPass());
     61   }
     62 };
     63 
     64 } // namespace
     65 
     66 static ExegesisTarget *getTheExegesisAArch64Target() {
     67   static ExegesisAArch64Target Target;
     68   return &Target;
     69 }
     70 
     71 void InitializeAArch64ExegesisTarget() {
     72   ExegesisTarget::registerTarget(getTheExegesisAArch64Target());
     73 }
     74 
     75 } // namespace exegesis
     76 } // namespace llvm
     77