tools/llvm-exegesis/lib/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
  10 #include "Latency.h"
  11 #include "Uops.h"
  12
  13 namespace llvm {
  14 namespace exegesis {
  15
  16 ExegesisTarget::~ExegesisTarget() {} // anchor.
  17
  18 static ExegesisTarget *FirstTarget = nullptr;
  19
  20 const ExegesisTarget *ExegesisTarget::lookup(llvm::Triple TT) {
  21   for (const ExegesisTarget *T = FirstTarget; T != nullptr; T = T->Next) {
  22     if (T->matchesArch(TT.getArch()))
  23       return T;
  24   }
  25   return nullptr;
  26 }
  27
  28 void ExegesisTarget::registerTarget(ExegesisTarget *Target) {
  29   if (FirstTarget == nullptr) {
  30     FirstTarget = Target;
  31     return;
  32   }
  33   if (Target->Next != nullptr)
  34     return; // Already registered.
  35   Target->Next = FirstTarget;
  36   FirstTarget = Target;
  37 }
  38
  39 std::unique_ptr<SnippetGenerator>
  40 ExegesisTarget::createSnippetGenerator(InstructionBenchmark::ModeE Mode,
  41                                        const LLVMState &State) const {
  42   switch (Mode) {
  43   case InstructionBenchmark::Unknown:
  44     return nullptr;
  45   case InstructionBenchmark::Latency:
  46     return createLatencySnippetGenerator(State);
  47   case InstructionBenchmark::Uops:
  48   case InstructionBenchmark::InverseThroughput:
  49     return createUopsSnippetGenerator(State);
  50   }
  51   return nullptr;
  52 }
  53
  54 std::unique_ptr<BenchmarkRunner>
  55 ExegesisTarget::createBenchmarkRunner(InstructionBenchmark::ModeE Mode,
  56                                       const LLVMState &State) const {
  57   switch (Mode) {
  58   case InstructionBenchmark::Unknown:
  59     return nullptr;
  60   case InstructionBenchmark::Latency:
  61   case InstructionBenchmark::InverseThroughput:
  62     return createLatencyBenchmarkRunner(State, Mode);
  63   case InstructionBenchmark::Uops:
  64     return createUopsBenchmarkRunner(State);
  65   }
  66   return nullptr;
  67 }
  68
  69 std::unique_ptr<SnippetGenerator>
  70 ExegesisTarget::createLatencySnippetGenerator(const LLVMState &State) const {
  71   return llvm::make_unique<LatencySnippetGenerator>(State);
  72 }
  73
  74 std::unique_ptr<SnippetGenerator>
  75 ExegesisTarget::createUopsSnippetGenerator(const LLVMState &State) const {
  76   return llvm::make_unique<UopsSnippetGenerator>(State);
  77 }
  78
  79 std::unique_ptr<BenchmarkRunner> ExegesisTarget::createLatencyBenchmarkRunner(
  80     const LLVMState &State, InstructionBenchmark::ModeE Mode) const {
  81   return llvm::make_unique<LatencyBenchmarkRunner>(State, Mode);
  82 }
  83
  84 std::unique_ptr<BenchmarkRunner>
  85 ExegesisTarget::createUopsBenchmarkRunner(const LLVMState &State) const {
  86   return llvm::make_unique<UopsBenchmarkRunner>(State);
  87 }
  88
  89 void ExegesisTarget::randomizeMCOperand(
  90     const Instruction &Instr, const Variable &Var,
  91     llvm::MCOperand &AssignedValue,
  92     const llvm::BitVector &ForbiddenRegs) const {
  93   const Operand &Op = Instr.getPrimaryOperand(Var);
  94   switch (Op.getExplicitOperandInfo().OperandType) {
  95   case llvm::MCOI::OperandType::OPERAND_IMMEDIATE:
  96     // FIXME: explore immediate values too.
  97     AssignedValue = llvm::MCOperand::createImm(1);
  98     break;
  99   case llvm::MCOI::OperandType::OPERAND_REGISTER: {
 100     assert(Op.isReg());
 101     auto AllowedRegs = Op.getRegisterAliasing().sourceBits();
 102     assert(AllowedRegs.size() == ForbiddenRegs.size());
 103     for (auto I : ForbiddenRegs.set_bits())
 104       AllowedRegs.reset(I);
 105     AssignedValue = llvm::MCOperand::createReg(randomBit(AllowedRegs));
 106     break;
 107   }
 108   default:
 109     break;
 110   }
 111 }
 112
 113 static_assert(std::is_pod<PfmCountersInfo>::value,
 114               "We shouldn't have dynamic initialization here");
 115 const PfmCountersInfo PfmCountersInfo::Default = {nullptr, nullptr, nullptr,
 116                                                   0u};
 117
 118 const PfmCountersInfo &
 119 ExegesisTarget::getPfmCounters(llvm::StringRef CpuName) const {
 120   assert(std::is_sorted(
 121              CpuPfmCounters.begin(), CpuPfmCounters.end(),
 122              [](const CpuAndPfmCounters &LHS, const CpuAndPfmCounters &RHS) {
 123                return strcmp(LHS.CpuName, RHS.CpuName) < 0;
 124              }) &&
 125          "CpuPfmCounters table is not sorted");
 126
 127   // Find entry
 128   auto Found =
 129       std::lower_bound(CpuPfmCounters.begin(), CpuPfmCounters.end(), CpuName);
 130   if (Found == CpuPfmCounters.end() ||
 131       llvm::StringRef(Found->CpuName) != CpuName) {
 132     // Use the default.
 133     if (CpuPfmCounters.begin() != CpuPfmCounters.end() &&
 134         CpuPfmCounters.begin()->CpuName[0] == '\0') {
 135       Found = CpuPfmCounters.begin(); // The target specifies a default.
 136     } else {
 137       return PfmCountersInfo::Default; // No default for the target.
 138     }
 139   }
 140   assert(Found->PCI && "Missing counters");
 141   return *Found->PCI;
 142 }
 143
 144 namespace {
 145
 146 // Default implementation.
 147 class ExegesisDefaultTarget : public ExegesisTarget {
 148 public:
 149   ExegesisDefaultTarget() : ExegesisTarget({}) {}
 150
 151 private:
 152   std::vector<llvm::MCInst> setRegTo(const llvm::MCSubtargetInfo &STI,
 153                                      unsigned Reg,
 154                                      const llvm::APInt &Value) const override {
 155     llvm_unreachable("Not yet implemented");
 156   }
 157
 158   bool matchesArch(llvm::Triple::ArchType Arch) const override {
 159     llvm_unreachable("never called");
 160     return false;
 161   }
 162 };
 163
 164 } // namespace
 165
 166 const ExegesisTarget &ExegesisTarget::getDefault() {
 167   static ExegesisDefaultTarget Target;
 168   return Target;
 169 }
 170
 171 } // namespace exegesis
 172 } // namespace llvm