tools/llvm-exegesis/lib/AArch64/Target.cpp

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