Instrumentor.cpp

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//===-- Instrumentor.cpp - Highly configurable instrumentation pass -------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// The implementation of the Instrumentor, a highly configurable instrumentation
// pass.
//
//===----------------------------------------------------------------------===//
 
#include "llvm/Transforms/IPO/Instrumentor.h"
#include "IPOOptions.h"
#include "llvm/Transforms/IPO/InstrumentorConfigFile.h"
#include "llvm/Transforms/IPO/InstrumentorRuntimeHelper.h"
#include "llvm/Transforms/IPO/InstrumentorStubPrinter.h"
 
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/iterator.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Demangle/Demangle.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/Verifier.h"
#include "llvm/IRReader/IRReader.h"
#include "llvm/Linker/Linker.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Regex.h"
#include "llvm/Support/VirtualFileSystem.h"
#include "llvm/Transforms/IPO/InstrumentorUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
#include "llvm/Transforms/Utils/PromoteMemToReg.h"
 
#include <cassert>
#include <cstdint>
#include <functional>
#include <iterator>
#include <memory>
#include <string>
#include <type_traits>
 
using namespace llvm;
using namespace llvm::instrumentor;
 
#define DEBUG_TYPE "instrumentor"
 
namespace {
 
/// The user option to specify input JSON files to read the configuration from.
static cl::list<std::string>
    ConfigFiles("instrumentor-read-config-files",
                cl::desc("Read the instrumentor configuration from the "
                         "specified JSON files (comma separated)"),
                cl::CommaSeparated);
 
/// Set the debug location, if not set, after changing the insertion point of
/// the IR builder \p IRB.
template <typename IRBuilderTy> void ensureDbgLoc(IRBuilderTy &IRB) {
  if (IRB.getCurrentDebugLocation())
    return;
  auto *BB = IRB.GetInsertBlock();
  if (auto *SP = BB->getParent()->getSubprogram())
    IRB.SetCurrentDebugLocation(DILocation::get(BB->getContext(), 0, 0, SP));
}
 
/// Attempt to cast \p V to type \p Ty using only bit-preserving casts.
/// This ensures that floating-point values are converted via bitcast (not
/// fptosi/fptoui) to preserve their exact bit representation.
template <typename IRBTy>
Value *tryToCast(IRBTy &IRB, Value *V, Type *Ty, const DataLayout &DL,
                 bool AllowTruncate = false) {
  if (!V)
    return Constant::getAllOnesValue(Ty);
  Type *VTy = V->getType();
  if (VTy == Ty)
    return V;
  if (VTy->isAggregateType() || VTy->isVectorTy())
    return V;
  if (VTy->isPointerTy() && Ty->isPointerTy())
    return IRB.CreatePointerBitCastOrAddrSpaceCast(V, Ty);
  TypeSize RequestedSize = DL.getTypeSizeInBits(Ty);
  TypeSize ValueSize = DL.getTypeSizeInBits(VTy);
  bool ShouldTruncate = RequestedSize < ValueSize;
  if (ShouldTruncate && !AllowTruncate)
    return V;
  if (ShouldTruncate && AllowTruncate) {
    // First convert to integer of the same size if needed.
    Value *IntV = V;
    if (VTy->isFloatingPointTy())
      IntV = IRB.CreateBitCast(V, IRB.getIntNTy(ValueSize));
    return tryToCast(IRB,
                     IRB.CreateIntCast(IntV, IRB.getIntNTy(RequestedSize),
                                       /*IsSigned=*/false),
                     Ty, DL, AllowTruncate);
  }
  if (VTy->isIntegerTy() && Ty->isIntegerTy())
    return IRB.CreateIntCast(V, Ty, /*IsSigned=*/false);
  // Use bit-preserving casts for floating-point values: convert float to int
  // of the same size via bitcast, then extend/truncate the integer if needed.
  if (VTy->isFloatingPointTy() && Ty->isIntOrPtrTy()) {
    return tryToCast(IRB, IRB.CreateBitCast(V, IRB.getIntNTy(ValueSize)), Ty,
                     DL, AllowTruncate);
  }
  // When converting int to float, never use sitofp/uitofp as they perform value
  // conversion, not bit-preserving cast.
  if (VTy->isIntegerTy() && Ty->isFloatingPointTy()) {
    if (ValueSize == RequestedSize)
      return IRB.CreateBitCast(V, Ty);
    return tryToCast(
        IRB,
        IRB.CreateIntCast(V, IRB.getIntNTy(RequestedSize), /*IsSigned=*/false),
        Ty, DL, AllowTruncate);
  }
  return IRB.CreateBitOrPointerCast(V, Ty);
}
 
/// Get a constant integer/boolean of type \p IT and value \p Val.
template <typename Ty>
Constant *getCI(Type *IT, Ty Val, bool IsSigned = false) {
  return ConstantInt::get(IT, Val, IsSigned);
}
 
Constant *getSubTypeID(Type &OpTy, Type &ReqTy) {
  switch (OpTy.getTypeID()) {
  case Type::TypeID::ArrayTyID:
  case Type::TypeID::FixedVectorTyID:
  case Type::TypeID::ScalableVectorTyID:
    return getCI(&ReqTy, OpTy.getContainedType(0)->getTypeID());
  default:
    break;
  }
 
  return getCI(&ReqTy, -1, /*IsSigned=*/true);
}
 
/// The core of the instrumentor pass, which instruments the module as the
/// instrumentation configuration mandates.
class InstrumentorImpl final {
public:
  /// Construct an instrumentor implementation using the configuration \p IConf.
  InstrumentorImpl(InstrumentationConfig &IConf, InstrumentorIRBuilderTy &IIRB,
                   Module &M)
      : IConf(IConf), M(M), IIRB(IIRB) {}
 
  /// Instrument the module, public entry point.
  bool instrument();
 
  // Reset the state to allow reuse of the instrumentor with a different
  // configuration.
  void clear() {
    InstChoicesPRE.clear();
    InstChoicesPOST.clear();
    ParsedFunctionRegex = Regex();
  }
 
private:
  /// Link the runtime bitcodes into the module. Returns true if the module
  /// was changed.
  bool linkRuntime();
 
  /// Indicate if the module should be instrumented based on the target.
  bool shouldInstrumentTarget();
 
  /// Indicate if the function \p Fn should be instrumented.
  bool shouldInstrumentFunction(Function &Fn);
  bool shouldInstrumentGlobalVariable(GlobalVariable &GV);
 
  /// Instrument instruction \p I if needed, and use the argument caches in \p
  /// ICaches.
  bool instrumentInstruction(Instruction &I, InstrumentationCaches &ICaches);
 
  /// Instrument function \p Fn.
  bool instrumentFunction(Function &Fn);
  bool instrumentModule();
 
  /// The instrumentation opportunities for instructions indexed by
  /// their opcode.
  DenseMap<unsigned, InstrumentationOpportunity *> InstChoicesPRE,
      InstChoicesPOST;
 
  /// The instrumentor configuration.
  InstrumentationConfig &IConf;
 
  /// The function regex filter, if any.
  Regex ParsedFunctionRegex;
 
  /// The underlying module.
  Module &M;
 
protected:
  /// A special IR builder that keeps track of the inserted instructions.
  InstrumentorIRBuilderTy &IIRB;
};
 
} // end anonymous namespace
 
static Regex createRegex(StringRef Str, StringRef Name, LLVMContext &Ctx) {
  if (!Str.empty()) {
    Regex RX(Str);
    std::string ErrMsg;
    if (!RX.isValid(ErrMsg)) {
      Ctx.diagnose(DiagnosticInfoInstrumentation(
          Twine("failed to parse ") + Name + " regex: " + ErrMsg, DS_Error));
      return Regex();
    }
    return RX;
  }
  return Regex();
}
 
bool InstrumentorImpl::linkRuntime() {
  ArrayRef<StringRef> RuntimeBitcodes = IConf.RuntimeBitcodes->getStringList();
  if (RuntimeBitcodes.empty())
    return false;
 
  bool Changed = false;
 
  for (StringRef RuntimeBitcode : RuntimeBitcodes) {
    if (RuntimeBitcode.empty())
      continue;
 
    SMDiagnostic Err;
    auto RTM = parseIRFile(RuntimeBitcode, Err, M.getContext());
    if (!RTM) {
      IIRB.Ctx.diagnose(DiagnosticInfoInstrumentation(
          Twine("Failed to parse runtime bitcode file '") + RuntimeBitcode +
              Twine("': ") + Err.getMessage(),
          DS_Error));
      return Changed;
    }
 
    if (Linker::linkModules(M, std::move(RTM))) {
      IIRB.Ctx.diagnose(DiagnosticInfoInstrumentation(
          Twine("Failed to link in runtime bitcode file '") + RuntimeBitcode +
              "'",
          DS_Error));
      return Changed;
    }
    Changed = true;
  }
 
  if (!IConf.InlineRuntimeEagerly->getBool())
    return Changed;
 
  for (auto [I, _] : IIRB.NewInsts) {
    auto *CI = dyn_cast<CallInst>(I);
    if (!CI || isa<IntrinsicInst>(CI))
      continue;
 
    InlineFunctionInfo IFI;
    auto InlineResult = InlineFunction(*CI, IFI);
    if (!InlineResult.isSuccess()) {
      std::string WarnMsg;
      raw_string_ostream SS(WarnMsg);
      SS << "Inlining of runtime call failed: "
         << CI->getCalledFunction()->getName() << "\n";
      SS << "Reason: " << InlineResult.getFailureReason() << "\n";
      SS << "Signatures: " << *CI->getFunctionType() << " vs "
         << *CI->getCalledFunction()->getFunctionType() << "\n";
      IIRB.Ctx.diagnose(DiagnosticInfoInstrumentation(WarnMsg, DS_Warning));
    }
  }
 
  // Promote any eligible instrumentor-associated allocas to registers.
  for (auto It : IIRB.AllocaMap) {
    auto *Fn = It.first.first;
    DominatorTree DT(*Fn);
    auto &Allocas = *It.second;
    erase_if(Allocas,
             [](const AllocaInst *AI) { return !isAllocaPromotable(AI); });
    PromoteMemToReg(Allocas, DT);
    delete It.second;
  }
  IIRB.AllocaMap.clear();
  return Changed;
}
 
bool InstrumentorImpl::shouldInstrumentTarget() {
  const Triple &T = M.getTargetTriple();
  const bool IsGPU = T.isAMDGPU() || T.isNVPTX();
 
  bool RegexMatches = true;
  Regex RX = createRegex(IConf.TargetRegex->getString(), "target", IIRB.Ctx);
  if (RX.isValid())
    RegexMatches = RX.match(T.str());
 
  // Only instrument the module if the target has to be instrumented.
  return ((IsGPU && IConf.GPUEnabled->getBool()) ||
          (!IsGPU && IConf.HostEnabled->getBool())) &&
         RegexMatches;
}
 
bool InstrumentorImpl::shouldInstrumentFunction(Function &Fn) {
  if (Fn.isDeclaration())
    return false;
  if (Fn.hasFnAttribute(Attribute::DisableSanitizerInstrumentation))
    return false;
  bool RegexMatches = true;
  if (ParsedFunctionRegex.isValid())
    RegexMatches = ParsedFunctionRegex.match(Fn.getName());
  return (RegexMatches && !Fn.getName().starts_with(IConf.getRTName())) ||
         Fn.hasFnAttribute("instrument");
}
 
bool InstrumentorImpl::shouldInstrumentGlobalVariable(GlobalVariable &GV) {
  return !GV.getName().starts_with("llvm.") &&
         !GV.getName().starts_with(IConf.getRTName());
}
 
bool InstrumentorImpl::instrumentInstruction(Instruction &I,
                                             InstrumentationCaches &ICaches) {
  bool Changed = false;
 
  // Skip instrumentation instructions.
  if (IIRB.NewInsts.contains(&I))
    return Changed;
 
  // Count epochs eagerly.
  ++IIRB.Epoch;
 
  Value *IPtr = &I;
  if (auto *IO = InstChoicesPRE.lookup(I.getOpcode())) {
    IIRB.IRB.SetInsertPoint(&I);
    ensureDbgLoc(IIRB.IRB);
    IO->instrument(IPtr, Changed, IConf, IIRB, ICaches);
  }
 
  if (auto *IO = InstChoicesPOST.lookup(I.getOpcode())) {
    IIRB.IRB.SetInsertPoint(I.getNextNode());
    ensureDbgLoc(IIRB.IRB);
    IO->instrument(IPtr, Changed, IConf, IIRB, ICaches);
  }
  IIRB.returnAllocas();
 
  return Changed;
}
 
bool InstrumentorImpl::instrumentFunction(Function &Fn) {
  bool Changed = false;
  if (!shouldInstrumentFunction(Fn))
    return Changed;
 
  InstrumentationCaches ICaches;
  SmallVector<Instruction *> FinalTIs;
  ReversePostOrderTraversal<Function *> RPOT(&Fn);
  for (auto &It : RPOT) {
    for (auto &I : *It)
      Changed |= instrumentInstruction(I, ICaches);
 
    auto *TI = It->getTerminator();
    if (!TI->getNumSuccessors())
      FinalTIs.push_back(TI);
  }
 
  Value *FPtr = &Fn;
  for (auto &[Name, IO] :
       IConf.IChoices[InstrumentationLocation::FUNCTION_PRE]) {
    if (!IO->Enabled)
      continue;
    // Count epochs eagerly.
    ++IIRB.Epoch;
 
    IIRB.IRB.SetInsertPoint(
        cast<Function>(FPtr)->getEntryBlock().getFirstNonPHIOrAlloca());
    ensureDbgLoc(IIRB.IRB);
    IO->instrument(FPtr, Changed, IConf, IIRB, ICaches);
    IIRB.returnAllocas();
  }
 
  for (auto &[Name, IO] :
       IConf.IChoices[InstrumentationLocation::FUNCTION_POST]) {
    if (!IO->Enabled)
      continue;
    // Count epochs eagerly.
    ++IIRB.Epoch;
 
    for (Instruction *FinalTI : FinalTIs) {
      IIRB.IRB.SetInsertPoint(FinalTI);
      ensureDbgLoc(IIRB.IRB);
      IO->instrument(FPtr, Changed, IConf, IIRB, ICaches);
      IIRB.returnAllocas();
    }
  }
  return Changed;
}
 
bool InstrumentorImpl::instrumentModule() {
  SmallVector<GlobalVariable *> Globals;
  Globals.reserve(M.global_size());
  for (GlobalVariable &GV : M.globals()) {
    // llvm.metadata contains globals such as llvm.used.
    if (GV.getSection() == "llvm.metadata" ||
        GV.getName() == "llvm.global_dtors" ||
        GV.getName() == "llvm.global_ctors")
      continue;
    Globals.push_back(&GV);
  }
 
  auto CreateYtor = [&](bool Ctor) {
    Function *YtorFn = Function::Create(
        FunctionType::get(IIRB.VoidTy, false), GlobalValue::PrivateLinkage,
        IConf.getRTName(Ctor ? "ctor" : "dtor", ""), M);
 
    auto *EntryBB = BasicBlock::Create(IIRB.Ctx, "entry", YtorFn);
    IIRB.IRB.SetInsertPoint(EntryBB->begin());
    ensureDbgLoc(IIRB.IRB);
    IIRB.IRB.CreateRetVoid();
 
    if (Ctor)
      appendToGlobalCtors(M, YtorFn, 1000);
    else
      appendToGlobalDtors(M, YtorFn, 1000);
    return YtorFn;
  };
 
  InstrumentationCaches ICaches;
 
  Function *CtorFn = nullptr, *DtorFn = nullptr;
  bool Changed = false;
  for (auto Loc : {InstrumentationLocation::MODULE_PRE,
                   InstrumentationLocation::MODULE_POST}) {
    bool IsPRE = InstrumentationLocation::isPRE(Loc);
    Function *&YtorFn = IsPRE ? CtorFn : DtorFn;
    for (auto &ChoiceIt : IConf.IChoices[Loc]) {
      auto *IO = ChoiceIt.second;
      if (!IO->Enabled)
        continue;
      if (!YtorFn) {
        YtorFn = CreateYtor(IsPRE);
        Changed = true;
      }
      IIRB.IRB.SetInsertPointPastAllocas(YtorFn);
      ensureDbgLoc(IIRB.IRB);
      Value *YtorPtr = YtorFn;
 
      // Count epochs eagerly.
      ++IIRB.Epoch;
 
      IO->instrument(YtorPtr, Changed, IConf, IIRB, ICaches);
      IIRB.returnAllocas();
    }
  }
 
  for (auto Loc : {InstrumentationLocation::GLOBAL_PRE,
                   InstrumentationLocation::GLOBAL_POST}) {
    bool IsPRE = InstrumentationLocation::isPRE(Loc);
    Function *&YtorFn = IsPRE ? CtorFn : DtorFn;
    for (auto &ChoiceIt : IConf.IChoices[Loc]) {
      auto *IO = ChoiceIt.second;
      if (!IO->Enabled)
        continue;
      if (!YtorFn) {
        YtorFn = CreateYtor(IsPRE);
        Changed = true;
      }
      for (GlobalVariable *GV : Globals) {
        if (!shouldInstrumentGlobalVariable(*GV))
          continue;
        if (IsPRE)
          IIRB.IRB.SetInsertPoint(YtorFn->getEntryBlock().getTerminator());
        else
          IIRB.IRB.SetInsertPointPastAllocas(YtorFn);
        ensureDbgLoc(IIRB.IRB);
        Value *GVPtr = GV;
 
        // Count epochs eagerly.
        ++IIRB.Epoch;
 
        IO->instrument(GVPtr, Changed, IConf, IIRB, ICaches);
        IIRB.returnAllocas();
      }
    }
  }
 
  return Changed;
}
 
bool InstrumentorImpl::instrument() {
  bool Changed = false;
  if (!shouldInstrumentTarget())
    return Changed;
 
  StringRef FunctionRegexStr = IConf.FunctionRegex->getString();
  ParsedFunctionRegex = createRegex(FunctionRegexStr, "function", IIRB.Ctx);
 
  // Helper to register an IO for all its opcodes.
  auto RegisterForAllOpcodes = [](auto &InstChoices,
                                  InstrumentationOpportunity *IO) {
    ArrayRef<unsigned> Opcodes = IO->getAllOpcodes();
    // Register for all opcodes.
    for (unsigned Opcode : Opcodes)
      InstChoices[Opcode] = IO;
  };
 
  for (auto &[Name, IO] :
       IConf.IChoices[InstrumentationLocation::INSTRUCTION_PRE])
    if (IO->Enabled)
      RegisterForAllOpcodes(InstChoicesPRE, IO);
  for (auto &[Name, IO] :
       IConf.IChoices[InstrumentationLocation::INSTRUCTION_POST])
    if (IO->Enabled)
      RegisterForAllOpcodes(InstChoicesPOST, IO);
  Changed |= instrumentModule();
 
  for (Function &Fn : M)
    Changed |= instrumentFunction(Fn);
 
  Changed |= linkRuntime();
 
  return Changed;
}
 
InstrumentorPass::InstrumentorPass(IntrusiveRefCntPtr<vfs::FileSystem> FS,
                                   InstrumentationConfig *IC,
                                   InstrumentorIRBuilderTy *IIRB)
    : FS(FS), UserIConf(IC), UserIIRB(IIRB) {
  if (!FS)
    this->FS = vfs::getRealFileSystem();
}
 
PreservedAnalyses InstrumentorPass::run(Module &M, InstrumentationConfig &IConf,
                                        InstrumentorIRBuilderTy &IIRB,
                                        bool ReadConfig) {
  const IPOOptions &Opts = getIPOOptions(M);
  bool Changed = false;
  InstrumentorImpl Impl(IConf, IIRB, M);
 
  // If this is a configuration driven run, iterate over all configurations
  // provided by the user, if not, use the config as is and run the instrumentor
  // once.
  if (ReadConfig)
    readConfigPathsFile(Opts.instrumentor_read_config_paths_file, ConfigFiles,
                        IIRB.Ctx, *FS);
 
  bool MultipleConfigs = ConfigFiles.size() > 1;
  unsigned Idx = 0;
  do {
    std::string ConfigFile =
        ReadConfig && !ConfigFiles.empty() ? ConfigFiles[Idx] : "";
 
    // Initialize the config to the base state but keep the caches around.
    Impl.clear();
    IConf.init(IIRB);
 
    if (!readConfigFromJSON(IConf, ConfigFile, IIRB.Ctx, *FS))
      continue;
 
    writeConfigToJSON(
        IConf,
        MultipleConfigs
            ? (Opts.instrumentor_write_config_file + "." + std::to_string(Idx))
                  .str()
            : Opts.instrumentor_write_config_file.str(),
        IIRB.Ctx);
 
    printRuntimeStub(IConf, IConf.RuntimeStubsFile->getString(), IIRB.Ctx);
 
    Changed |= Impl.instrument();
  } while (++Idx < ConfigFiles.size());
 
  if (!Changed)
    return PreservedAnalyses::all();
  return PreservedAnalyses::none();
}
 
PreservedAnalyses InstrumentorPass::run(Module &M, ModuleAnalysisManager &MAM) {
  // Only create them if the user did not provide them.
  std::unique_ptr<InstrumentationConfig> IConfInt(
      !UserIConf ? new InstrumentationConfig() : nullptr);
  std::unique_ptr<InstrumentorIRBuilderTy> IIRBInt(
      !UserIIRB ? new InstrumentorIRBuilderTy(M) : nullptr);
 
  auto *IConf = IConfInt ? IConfInt.get() : UserIConf;
  auto *IIRB = IIRBInt ? IIRBInt.get() : UserIIRB;
 
  auto PA = run(M, *IConf, *IIRB, !UserIConf);
 
  assert(!verifyModule(M, &errs()));
  return PA;
}
 
std::unique_ptr<BaseConfigurationOption>
BaseConfigurationOption::createBoolOption(InstrumentationConfig &IConf,
                                          StringRef Name, StringRef Description,
                                          bool DefaultValue) {
  auto BCO =
      std::make_unique<BaseConfigurationOption>(Name, Description, BOOLEAN);
  BCO->setBool(DefaultValue);
  IConf.addBaseChoice(BCO.get());
  return BCO;
}
 
std::unique_ptr<BaseConfigurationOption>
BaseConfigurationOption::createStringOption(InstrumentationConfig &IConf,
                                            StringRef Name,
                                            StringRef Description,
                                            StringRef DefaultValue) {
  auto BCO =
      std::make_unique<BaseConfigurationOption>(Name, Description, STRING);
  BCO->setString(DefaultValue);
  IConf.addBaseChoice(BCO.get());
  return BCO;
}
 
std::unique_ptr<BaseConfigurationOption>
BaseConfigurationOption::createStringListOption(
    InstrumentationConfig &IConf, StringRef Name, StringRef Description,
    ArrayRef<StringRef> DefaultValue) {
  auto BCO =
      std::make_unique<BaseConfigurationOption>(Name, Description, STRING_LIST);
  BCO->setStringList(DefaultValue);
  IConf.addBaseChoice(BCO.get());
  return BCO;
}
 
void InstrumentationConfig::populate(InstrumentorIRBuilderTy &IIRB) {
  /// List of all instrumentation opportunities.
  BasePointerIO::populate(*this, IIRB);
  ModuleIO::populate(*this, IIRB);
  GlobalVarIO::populate(*this, IIRB);
  FunctionIO::populate(*this, IIRB);
  AllocaIO::populate(*this, IIRB);
  UnreachableIO::populate(*this, IIRB);
  LoadIO::populate(*this, IIRB);
  StoreIO::populate(*this, IIRB);
  CastIO::populate(*this, IIRB);
  NumericIO::populate(*this, IIRB);
  CompareIO::populate(*this, IIRB);
}
 
void InstrumentationConfig::addChoice(InstrumentationOpportunity &IO,
                                      LLVMContext &Ctx) {
  auto *&ICPtr = IChoices[IO.getLocationKind()][IO.getName()];
  if (ICPtr) {
    Ctx.diagnose(DiagnosticInfoInstrumentation(
        Twine("registered two instrumentation opportunities for the same "
              "location (") +
            ICPtr->getName() + Twine(" vs ") + IO.getName() + Twine(")"),
        DS_Warning));
  }
  ICPtr = &IO;
}
 
Value *
InstrumentationConfig::getBasePointerInfo(Value &V,
                                          InstrumentorIRBuilderTy &IIRB) {
  Function *Fn = IIRB.IRB.GetInsertBlock()->getParent();
 
  Value *Obj;
  {
    Value *&UnderlyingObj = UnderlyingObjsMap[&V];
    if (!UnderlyingObj)
      UnderlyingObj = const_cast<Value *>(getUnderlyingObjectAggressive(&V));
    Obj = UnderlyingObj;
  }
 
  Value *&BPI = BasePointerInfoMap[{Obj, Fn}];
  if (BPI)
    return BPI;
 
  auto *BPIO =
      IChoices[InstrumentationLocation::SPECIAL_VALUE]["base_pointer_info"];
  if (!BPIO || !BPIO->Enabled) {
    IIRB.Ctx.diagnose(DiagnosticInfoInstrumentation(
        "Base pointer info disabled but required, passing nullptr.",
        DS_Warning));
    return BPI = Constant::getNullValue(BPIO->getRetTy(IIRB.Ctx));
  }
 
  IRBuilderBase::InsertPointGuard IP(IIRB.IRB);
  if (auto *BasePtrI = dyn_cast<Instruction>(Obj)) {
    std::optional<BasicBlock::iterator> IP =
        BasePtrI->getInsertionPointAfterDef();
    if (IP) {
      IIRB.IRB.SetInsertPoint(*IP);
    } else {
      IIRB.Ctx.diagnose(DiagnosticInfoInstrumentation(
          "Base pointer info could not be placed, passing nullptr.",
          DS_Warning));
      return BPI = Constant::getNullValue(BPIO->getRetTy(IIRB.Ctx));
    }
  } else if (isa<Constant>(Obj) || isa<Argument>(Obj)) {
    IIRB.IRB.SetInsertPointPastAllocas(IIRB.IRB.GetInsertBlock()->getParent());
  } else {
    LLVM_DEBUG(Obj->dump());
    llvm_unreachable("Unexpected base pointer!");
  }
  ensureDbgLoc(IIRB.IRB);
 
  // Use fresh caches for safety, as this function may be called from
  // another instrumentation opportunity.
  bool Changed;
  InstrumentationCaches ICaches;
  BPI = BPIO->instrument(Obj, Changed, *this, IIRB, ICaches);
  IIRB.returnAllocas();
  if (!BPI)
    BPI = Constant::getNullValue(BPIO->getRetTy(IIRB.Ctx));
  return BPI;
}
 
Value *InstrumentationOpportunity::getIdPre(Value &V, Type &Ty,
                                            InstrumentationConfig &IConf,
                                            InstrumentorIRBuilderTy &IIRB) {
  return getCI(&Ty, getIdFromEpoch(IIRB.Epoch));
}
 
Value *InstrumentationOpportunity::getIdPost(Value &V, Type &Ty,
                                             InstrumentationConfig &IConf,
                                             InstrumentorIRBuilderTy &IIRB) {
  return getCI(&Ty, -getIdFromEpoch(IIRB.Epoch), /*IsSigned=*/true);
}
 
Value *InstrumentationOpportunity::forceCast(Value &V, Type &Ty,
                                             InstrumentorIRBuilderTy &IIRB) {
  if (V.getType()->isVoidTy())
    return Ty.isVoidTy() ? &V : Constant::getNullValue(&Ty);
  return tryToCast(IIRB.IRB, &V, &Ty, IIRB.IRB.getDataLayout());
}
 
Value *InstrumentationOpportunity::replaceValue(Value &V, Value &NewV,
                                                InstrumentationConfig &IConf,
                                                InstrumentorIRBuilderTy &IIRB) {
  if (V.getType()->isVoidTy())
    return &V;
 
  auto *NewVCasted = &NewV;
  if (auto *I = dyn_cast<Instruction>(&NewV)) {
    IRBuilderBase::InsertPointGuard IPG(IIRB.IRB);
    IIRB.IRB.SetInsertPoint(I->getNextNode());
    ensureDbgLoc(IIRB.IRB);
    NewVCasted = tryToCast(IIRB.IRB, &NewV, V.getType(), IIRB.DL,
                           /*AllowTruncate=*/true);
  }
  V.replaceUsesWithIf(NewVCasted, [&](Use &U) {
    if (IIRB.NewInsts.lookup(cast<Instruction>(U.getUser())) == IIRB.Epoch)
      return false;
    return !isa<LifetimeIntrinsic>(U.getUser()) && !U.getUser()->isDroppable();
  });
 
  return &V;
}
 
IRTCallDescription::IRTCallDescription(InstrumentationOpportunity &IO,
                                       Type *RetTy)
    : IO(IO), RetTy(RetTy) {
  for (auto &It : IO.IRTArgs) {
    if (!It.Enabled)
      continue;
    NumReplaceableArgs += bool(It.Flags & IRTArg::REPLACABLE);
    MightRequireIndirection |= It.Flags & IRTArg::POTENTIALLY_INDIRECT;
  }
  if (NumReplaceableArgs > 1)
    MightRequireIndirection = RequiresIndirection = true;
}
 
FunctionType *IRTCallDescription::createLLVMSignature(
    InstrumentationConfig &IConf, InstrumentorIRBuilderTy &IIRB,
    const DataLayout &DL, bool ForceIndirection) {
  assert(((ForceIndirection && MightRequireIndirection) ||
          (!ForceIndirection && !RequiresIndirection)) &&
         "Wrong indirection setting!");
 
  SmallVector<Type *> ParamTypes;
  for (auto &It : IO.IRTArgs) {
    if (!It.Enabled)
      continue;
    if (!ForceIndirection || !isPotentiallyIndirect(It)) {
      ParamTypes.push_back(It.Ty);
      if (!RetTy && NumReplaceableArgs == 1 && (It.Flags & IRTArg::REPLACABLE))
        RetTy = It.Ty;
      continue;
    }
 
    // The indirection pointer and the size of the value.
    ParamTypes.push_back(IIRB.PtrTy);
    if (!(It.Flags & IRTArg::INDIRECT_HAS_SIZE))
      ParamTypes.push_back(IIRB.Int32Ty);
  }
  if (!RetTy)
    RetTy = IIRB.VoidTy;
 
  return FunctionType::get(RetTy, ParamTypes, /*isVarArg=*/false);
}
 
CallInst *IRTCallDescription::createLLVMCall(Value *&V,
                                             InstrumentationConfig &IConf,
                                             InstrumentorIRBuilderTy &IIRB,
                                             const DataLayout &DL,
                                             InstrumentationCaches &ICaches) {
  SmallVector<Value *> CallParams;
 
  IRBuilderBase::InsertPointGuard IRP(IIRB.IRB);
  auto IP = IIRB.IRB.GetInsertPoint();
 
  bool ForceIndirection = RequiresIndirection;
  for (auto &It : IO.IRTArgs) {
    if (!It.Enabled)
      continue;
    auto *&Param = ICaches.DirectArgCache[{IIRB.Epoch, IO.getName(), It.Name}];
    if (!Param || It.NoCache)
      // Avoid passing the caches to the getter.
      Param = It.GetterCB(*V, *It.Ty, IConf, IIRB);
    assert(Param);
 
    if (Param->getType()->isVoidTy()) {
      Param = Constant::getNullValue(It.Ty);
    } else if (Param->getType()->isAggregateType() ||
               Param->getType()->isVectorTy() ||
               DL.getTypeSizeInBits(Param->getType()) >
                   DL.getTypeSizeInBits(It.Ty)) {
      if (!isPotentiallyIndirect(It)) {
        IIRB.Ctx.diagnose(DiagnosticInfoInstrumentation(
            Twine("indirection needed for ") + It.Name + Twine(" in ") +
                IO.getName() +
                Twine(", but not indicated. Instrumentation is skipped"),
            DS_Warning));
        return nullptr;
      }
      ForceIndirection = true;
    } else {
      Param = tryToCast(IIRB.IRB, Param, It.Ty, DL);
    }
    CallParams.push_back(Param);
  }
 
  if (ForceIndirection) {
    Function *Fn = IIRB.IRB.GetInsertBlock()->getParent();
 
    unsigned Offset = 0;
    for (auto &It : IO.IRTArgs) {
      if (!It.Enabled)
        continue;
 
      if (!isPotentiallyIndirect(It)) {
        ++Offset;
        continue;
      }
      auto *&CallParam = CallParams[Offset++];
      if (!(It.Flags & IRTArg::INDIRECT_HAS_SIZE)) {
        CallParams.insert(&CallParam + 1, IIRB.IRB.getInt32(DL.getTypeStoreSize(
                                              CallParam->getType())));
        Offset += 1;
      }
 
      auto *&CachedParam =
          ICaches.IndirectArgCache[{IIRB.Epoch, IO.getName(), It.Name}];
      if (CachedParam) {
        CallParam = CachedParam;
        continue;
      }
 
      auto *AI = IIRB.getAlloca(Fn, CallParam->getType());
      IIRB.IRB.CreateStore(CallParam, AI);
      CallParam = CachedParam = tryToCast(IIRB.IRB, AI, IIRB.PtrTy, DL);
    }
  }
 
  if (!ForceIndirection)
    IIRB.IRB.SetInsertPoint(IP);
  ensureDbgLoc(IIRB.IRB);
 
  auto *FnTy = createLLVMSignature(IConf, IIRB, DL, ForceIndirection);
  auto CompleteName =
      IConf.getRTName(IO.IP.isPRE() ? "pre_" : "post_", IO.getName(),
                      ForceIndirection ? "_ind" : "");
  auto FC = IIRB.IRB.getModule()->getOrInsertFunction(CompleteName, FnTy);
  auto *CI = IIRB.IRB.CreateCall(FC, CallParams);
  CI->addFnAttr(Attribute::get(IIRB.Ctx, Attribute::WillReturn));
 
  for (unsigned I = 0, E = IO.IRTArgs.size(); I < E; ++I) {
    if (!IO.IRTArgs[I].Enabled)
      continue;
    if (!isReplacable(IO.IRTArgs[I]))
      continue;
    bool IsCustomReplaceable = IO.IRTArgs[I].Flags & IRTArg::REPLACABLE_CUSTOM;
    Value *NewValue = FnTy->isVoidTy() || IsCustomReplaceable
                          ? ICaches.DirectArgCache[{IIRB.Epoch, IO.getName(),
                                                    IO.IRTArgs[I].Name}]
                          : CI;
    assert(NewValue);
    if (ForceIndirection && !IsCustomReplaceable &&
        isPotentiallyIndirect(IO.IRTArgs[I])) {
      auto *Q =
          ICaches
              .IndirectArgCache[{IIRB.Epoch, IO.getName(), IO.IRTArgs[I].Name}];
      NewValue = IIRB.IRB.CreateLoad(V->getType(), Q);
    }
    V = IO.IRTArgs[I].SetterCB(*V, *NewValue, IConf, IIRB);
  }
  return CI;
}
 
template <typename Ty> constexpr static Value *getValue(Ty &ValueOrUse) {
  if constexpr (std::is_same<Ty, Use>::value)
    return ValueOrUse.get();
  else
    return static_cast<Value *>(&ValueOrUse);
}
 
template <typename Range>
static Value *createValuePack(const Range &R, InstrumentationConfig &IConf,
                              InstrumentorIRBuilderTy &IIRB) {
  auto *Fn = IIRB.IRB.GetInsertBlock()->getParent();
  auto *I32Ty = IIRB.IRB.getInt32Ty();
  SmallVector<Constant *> ConstantValues;
  SmallVector<std::pair<Value *, uint32_t>> Values;
  SmallVector<Type *> Types;
  for (auto &RE : R) {
    Value *V = getValue(RE);
    if (!V->getType()->isSized())
      continue;
    auto VSize = IIRB.DL.getTypeAllocSize(V->getType());
    ConstantValues.push_back(getCI(I32Ty, VSize));
    Types.push_back(I32Ty);
    ConstantValues.push_back(getCI(I32Ty, V->getType()->getTypeID()));
    Types.push_back(I32Ty);
    if (uint32_t MisAlign = VSize % 8) {
      Types.push_back(ArrayType::get(IIRB.Int8Ty, 8 - MisAlign));
      ConstantValues.push_back(ConstantArray::getNullValue(Types.back()));
    }
    Types.push_back(V->getType());
    if (auto *C = dyn_cast<Constant>(V)) {
      ConstantValues.push_back(C);
      continue;
    }
    Values.push_back({V, ConstantValues.size()});
    ConstantValues.push_back(Constant::getNullValue(V->getType()));
  }
  if (Types.empty())
    return ConstantPointerNull::get(IIRB.PtrTy);
 
  StructType *STy = StructType::get(Fn->getContext(), Types, /*isPacked=*/true);
  Constant *Initializer = ConstantStruct::get(STy, ConstantValues);
 
  GlobalVariable *&GV = IConf.ConstantGlobalsCache[Initializer];
  if (!GV)
    GV = new GlobalVariable(*Fn->getParent(), STy, false,
                            GlobalValue::InternalLinkage, Initializer,
                            IConf.getRTName("", "value_pack"));
 
  auto *AI = IIRB.getAlloca(Fn, STy);
  IIRB.IRB.CreateMemCpy(AI, AI->getAlign(), GV, GV->getAlign(),
                        IIRB.DL.getTypeAllocSize(STy));
  for (auto [Param, Idx] : Values) {
    auto *Ptr = IIRB.IRB.CreateStructGEP(STy, AI, Idx);
    IIRB.IRB.CreateStore(Param, Ptr);
  }
  return AI;
}
 
template <typename Range>
static void readValuePack(const Range &R, Value &Pack,
                          InstrumentorIRBuilderTy &IIRB,
                          function_ref<void(int, Value *)> SetterCB) {
  auto *Fn = IIRB.IRB.GetInsertBlock()->getParent();
  auto &DL = Fn->getDataLayout();
  unsigned Offset = 0;
  for (const auto &[Idx, RE] : enumerate(R)) {
    Value *V = getValue(RE);
    if (!V->getType()->isSized())
      continue;
    Offset += 8;
    auto VSize = DL.getTypeAllocSize(V->getType());
    auto Padding = alignTo(VSize, 8) - VSize;
    Offset += Padding;
    auto *Ptr = IIRB.IRB.CreateConstInBoundsGEP1_32(IIRB.Int8Ty, &Pack, Offset);
    auto *NewV = IIRB.IRB.CreateLoad(V->getType(), Ptr);
    SetterCB(Idx, NewV);
    Offset += VSize;
  }
}
 
Value *BaseInstructionIO::getOpcode(Value &V, Type &Ty,
                                    InstrumentationConfig &IConf,
                                    InstrumentorIRBuilderTy &IIRB) {
  auto &I = cast<Instruction>(V);
  return getCI(&Ty, I.getOpcode());
}
 
Value *BaseInstructionIO::getTypeSize(Value &V, Type &Ty,
                                      InstrumentationConfig &IConf,
                                      InstrumentorIRBuilderTy &IIRB) {
  auto &I = cast<Instruction>(V);
  auto &DL = I.getDataLayout();
  return getCI(&Ty, DL.getTypeStoreSize(V.getType()));
}
 
Value *BaseInstructionIO::getLeftOperand(Value &V, Type &Ty,
                                         InstrumentationConfig &IConf,
                                         InstrumentorIRBuilderTy &IIRB) {
  auto &I = cast<Instruction>(V);
  return I.getOperand(0);
}
 
Value *BaseInstructionIO::getRightOperand(Value &V, Type &Ty,
                                          InstrumentationConfig &IConf,
                                          InstrumentorIRBuilderTy &IIRB) {
  auto &I = cast<Instruction>(V);
  if (I.getNumOperands() > 1)
    return I.getOperand(1);
  return PoisonValue::get(&Ty);
}
 
Value *BaseInstructionIO::getTypeId(Value &V, Type &Ty,
                                    InstrumentationConfig &IConf,
                                    InstrumentorIRBuilderTy &IIRB) {
  return getCI(&Ty, V.getType()->getTypeID());
}
 
Value *BaseInstructionIO::getSubTypeId(Value &V, Type &Ty,
                                       InstrumentationConfig &IConf,
                                       InstrumentorIRBuilderTy &IIRB) {
  return getSubTypeID(*V.getType(), Ty);
}
 
/// FunctionIO
/// {
void FunctionIO::init(InstrumentationConfig &IConf,
                      InstrumentorIRBuilderTy &IIRB, ConfigTy *UserConfig) {
  using namespace std::placeholders;
  if (UserConfig)
    Config = *UserConfig;
 
  bool IsPRE = getLocationKind() == InstrumentationLocation::FUNCTION_PRE;
  if (Config.has(PassAddress))
    IRTArgs.push_back(IRTArg(IIRB.PtrTy, "address", "The function address.",
                             IRTArg::NONE, getFunctionAddress));
  if (Config.has(PassName))
    IRTArgs.push_back(IRTArg(IIRB.PtrTy, "name", "The function name.",
                             IRTArg::STRING, getFunctionName));
  if (Config.has(PassNumArguments))
    IRTArgs.push_back(
        IRTArg(IIRB.Int32Ty, "num_arguments",
               "Number of function arguments (without varargs).", IRTArg::NONE,
               std::bind(&FunctionIO::getNumArguments, this, _1, _2, _3, _4)));
  if (Config.has(PassArguments))
    IRTArgs.push_back(IRTArg(
        IIRB.PtrTy, "arguments", "Description of the arguments.",
        (IsPRE && Config.has(ReplaceArguments) ? IRTArg::REPLACABLE_CUSTOM
                                               : IRTArg::NONE) |
            IRTArg::VALUE_PACK,
        std::bind(&FunctionIO::getArguments, this, _1, _2, _3, _4),
        std::bind(&FunctionIO::setArguments, this, _1, _2, _3, _4)));
  if (Config.has(PassIsMain))
    IRTArgs.push_back(IRTArg(IIRB.Int8Ty, "is_main",
                             "Flag to indicate it is the main function.",
                             IRTArg::NONE, isMainFunction));
  addCommonArgs(IConf, IIRB.Ctx, Config.has(PassId));
  IConf.addChoice(*this, IIRB.Ctx);
}
 
Value *FunctionIO::getFunctionAddress(Value &V, Type &Ty,
                                      InstrumentationConfig &IConf,
                                      InstrumentorIRBuilderTy &IIRB) {
  auto &Fn = cast<Function>(V);
  if (Fn.isIntrinsic())
    return Constant::getNullValue(&Ty);
  return &V;
}
Value *FunctionIO::getFunctionName(Value &V, Type &Ty,
                                   InstrumentationConfig &IConf,
                                   InstrumentorIRBuilderTy &IIRB) {
  auto &Fn = cast<Function>(V);
  return IConf.getGlobalString(IConf.DemangleFunctionNames->getBool()
                                   ? demangle(Fn.getName())
                                   : Fn.getName(),
                               IIRB);
}
Value *FunctionIO::getNumArguments(Value &V, Type &Ty,
                                   InstrumentationConfig &IConf,
                                   InstrumentorIRBuilderTy &IIRB) {
  auto &Fn = cast<Function>(V);
  if (!Config.ArgFilter)
    return getCI(&Ty, Fn.arg_size());
  auto FRange = make_filter_range(Fn.args(), Config.ArgFilter);
  return getCI(&Ty, std::distance(FRange.begin(), FRange.end()));
}
Value *FunctionIO::getArguments(Value &V, Type &Ty,
                                InstrumentationConfig &IConf,
                                InstrumentorIRBuilderTy &IIRB) {
  auto &Fn = cast<Function>(V);
  if (!Config.ArgFilter)
    return createValuePack(Fn.args(), IConf, IIRB);
  return createValuePack(make_filter_range(Fn.args(), Config.ArgFilter), IConf,
                         IIRB);
}
Value *FunctionIO::setArguments(Value &V, Value &NewV,
                                InstrumentationConfig &IConf,
                                InstrumentorIRBuilderTy &IIRB) {
  auto &Fn = cast<Function>(V);
  auto *AIt = Fn.arg_begin();
  auto CB = [&](int Idx, Value *ReplV) {
    while (Config.ArgFilter && !Config.ArgFilter(*AIt))
      ++AIt;
    Fn.getArg(Idx)->replaceUsesWithIf(ReplV, [&](Use &U) {
      return IIRB.NewInsts.lookup(cast<Instruction>(U.getUser())) != IIRB.Epoch;
    });
    ++AIt;
  };
  if (!Config.ArgFilter)
    readValuePack(Fn.args(), NewV, IIRB, CB);
  else
    readValuePack(make_filter_range(Fn.args(), Config.ArgFilter), NewV, IIRB,
                  CB);
  return &Fn;
}
Value *FunctionIO::isMainFunction(Value &V, Type &Ty,
                                  InstrumentationConfig &IConf,
                                  InstrumentorIRBuilderTy &IIRB) {
  auto &Fn = cast<Function>(V);
  return getCI(&Ty, Fn.getName() == "main");
}
 
/// UnreachableIO
///{
void UnreachableIO::init(InstrumentationConfig &IConf,
                         InstrumentorIRBuilderTy &IIRB, ConfigTy *UserConfig) {
  if (UserConfig)
    Config = *UserConfig;
  addCommonArgs(IConf, IIRB.Ctx, Config.has(PassId));
  IConf.addChoice(*this, IIRB.Ctx);
}
///}
 
/// AllocaIO
///{
void AllocaIO::init(InstrumentationConfig &IConf, InstrumentorIRBuilderTy &IIRB,
                    ConfigTy *UserConfig) {
  if (UserConfig)
    Config = *UserConfig;
 
  bool IsPRE = getLocationKind() == InstrumentationLocation::INSTRUCTION_PRE;
  if (!IsPRE && Config.has(PassAddress))
    IRTArgs.push_back(
        IRTArg(IIRB.PtrTy, "address", "The allocated memory address.",
               Config.has(ReplaceAddress) ? IRTArg::REPLACABLE : IRTArg::NONE,
               InstrumentationOpportunity::getValue,
               InstrumentationOpportunity::replaceValue));
  if (Config.has(PassSize))
    IRTArgs.push_back(IRTArg(
        IIRB.Int64Ty, "size", "The allocation size.",
        (IsPRE && Config.has(ReplaceSize)) ? IRTArg::REPLACABLE : IRTArg::NONE,
        getSize, setSize));
  if (Config.has(PassAlignment))
    IRTArgs.push_back(IRTArg(IIRB.Int64Ty, "alignment",
                             "The allocation alignment.", IRTArg::NONE,
                             getAlignment));
 
  addCommonArgs(IConf, IIRB.Ctx, Config.has(PassId));
  IConf.addChoice(*this, IIRB.Ctx);
}
 
Value *AllocaIO::getSize(Value &V, Type &Ty, InstrumentationConfig &IO,
                         InstrumentorIRBuilderTy &IIRB) {
  auto &AI = cast<AllocaInst>(V);
  return IIRB.IRB.CreateAllocationSize(&Ty, &AI);
}
 
Value *AllocaIO::setSize(Value &V, Value &NewV, InstrumentationConfig &IO,
                         InstrumentorIRBuilderTy &IIRB) {
  auto &AI = cast<AllocaInst>(V);
  const DataLayout &DL = AI.getDataLayout();
  auto *NewAI = IIRB.IRB.CreateAlloca(IIRB.IRB.getInt8Ty(),
                                      DL.getAllocaAddrSpace(), &NewV);
  NewAI->setAlignment(AI.getAlign());
  AI.replaceAllUsesWith(NewAI);
  IIRB.eraseLater(&AI);
  return NewAI;
}
 
Value *AllocaIO::getAlignment(Value &V, Type &Ty, InstrumentationConfig &IConf,
                              InstrumentorIRBuilderTy &IIRB) {
  return getCI(&Ty, cast<AllocaInst>(V).getAlign().value());
}
///}
 
void StoreIO::init(InstrumentationConfig &IConf, InstrumentorIRBuilderTy &IIRB,
                   ConfigTy *UserConfig) {
  if (UserConfig)
    Config = *UserConfig;
 
  bool IsPRE = getLocationKind() == InstrumentationLocation::INSTRUCTION_PRE;
  if (Config.has(PassPointer)) {
    IRTArgs.push_back(
        IRTArg(IIRB.PtrTy, "pointer", "The accessed pointer.",
               ((IsPRE && Config.has(ReplacePointer)) ? IRTArg::REPLACABLE
                                                      : IRTArg::NONE),
               getPointer, setPointer));
  }
  if (Config.has(PassPointerAS)) {
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "pointer_as",
                             "The address space of the accessed pointer.",
                             IRTArg::NONE, getPointerAS));
  }
  if (Config.has(PassBasePointerInfo)) {
    IRTArgs.push_back(IRTArg(IIRB.PtrTy, "base_pointer_info",
                             "The runtime provided base pointer info.",
                             IRTArg::NONE, getBasePointerInfo));
  }
  if (Config.has(PassStoredValue)) {
    IRTArgs.push_back(
        IRTArg(getValueType(IIRB), "value", "The stored value.",
               IRTArg::POTENTIALLY_INDIRECT |
                   (Config.has(PassStoredValueSize) ? IRTArg::INDIRECT_HAS_SIZE
                                                    : IRTArg::NONE),
               getValue));
  }
  if (Config.has(PassStoredValueSize)) {
    IRTArgs.push_back(IRTArg(IIRB.Int64Ty, "value_size",
                             "The size of the stored value.", IRTArg::NONE,
                             getValueSize));
  }
  if (Config.has(PassAlignment)) {
    IRTArgs.push_back(IRTArg(IIRB.Int64Ty, "alignment",
                             "The known access alignment.", IRTArg::NONE,
                             getAlignment));
  }
  if (Config.has(PassValueTypeId)) {
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "value_type_id",
                             "The type id of the stored value.", IRTArg::TYPEID,
                             getValueTypeId));
  }
  if (Config.has(PassValueSubTypeId)) {
    IRTArgs.push_back(IRTArg(
        IIRB.Int32Ty, "value_sub_type_id",
        "The type id of the stored value (for arrays and vectors, or -1).",
        IRTArg::TYPEID, getValueSubTypeId));
  }
  if (Config.has(PassAtomicityOrdering)) {
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "atomicity_ordering",
                             "The atomicity ordering of the store.",
                             IRTArg::NONE, getAtomicityOrdering));
  }
  if (Config.has(PassSyncScopeId)) {
    IRTArgs.push_back(IRTArg(IIRB.Int8Ty, "sync_scope_id",
                             "The sync scope id of the store.", IRTArg::NONE,
                             getSyncScopeId));
  }
  if (Config.has(PassIsVolatile)) {
    IRTArgs.push_back(IRTArg(IIRB.Int8Ty, "is_volatile",
                             "Flag indicating a volatile store.", IRTArg::NONE,
                             isVolatile));
  }
 
  addCommonArgs(IConf, IIRB.Ctx, Config.has(PassId));
  IConf.addChoice(*this, IIRB.Ctx);
}
 
Value *StoreIO::getPointer(Value &V, Type &Ty, InstrumentationConfig &IConf,
                           InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  return SI.getPointerOperand();
}
 
Value *StoreIO::setPointer(Value &V, Value &NewV, InstrumentationConfig &IConf,
                           InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  SI.setOperand(SI.getPointerOperandIndex(), &NewV);
  return &SI;
}
 
Value *StoreIO::getPointerAS(Value &V, Type &Ty, InstrumentationConfig &IConf,
                             InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  return getCI(&Ty, SI.getPointerAddressSpace());
}
 
Value *StoreIO::getBasePointerInfo(Value &V, Type &Ty,
                                   InstrumentationConfig &IConf,
                                   InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  return IConf.getBasePointerInfo(*SI.getPointerOperand(), IIRB);
}
 
Value *StoreIO::getValue(Value &V, Type &Ty, InstrumentationConfig &IConf,
                         InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  return SI.getValueOperand();
}
 
Value *StoreIO::getValueSize(Value &V, Type &Ty, InstrumentationConfig &IConf,
                             InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  auto &DL = SI.getDataLayout();
  return getCI(&Ty, DL.getTypeStoreSize(SI.getValueOperand()->getType()));
}
 
Value *StoreIO::getAlignment(Value &V, Type &Ty, InstrumentationConfig &IConf,
                             InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  return getCI(&Ty, SI.getAlign().value());
}
 
Value *StoreIO::getValueTypeId(Value &V, Type &Ty, InstrumentationConfig &IConf,
                               InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  return getCI(&Ty, SI.getValueOperand()->getType()->getTypeID());
}
 
Value *StoreIO::getValueSubTypeId(Value &V, Type &Ty,
                                  InstrumentationConfig &IConf,
                                  InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  return getSubTypeID(*SI.getValueOperand()->getType(), Ty);
}
 
Value *StoreIO::getAtomicityOrdering(Value &V, Type &Ty,
                                     InstrumentationConfig &IConf,
                                     InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  return getCI(&Ty, uint64_t(SI.getOrdering()));
}
 
Value *StoreIO::getSyncScopeId(Value &V, Type &Ty, InstrumentationConfig &IConf,
                               InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  return getCI(&Ty, uint64_t(SI.getSyncScopeID()));
}
 
Value *StoreIO::isVolatile(Value &V, Type &Ty, InstrumentationConfig &IConf,
                           InstrumentorIRBuilderTy &IIRB) {
  auto &SI = cast<StoreInst>(V);
  return getCI(&Ty, SI.isVolatile());
}
 
void LoadIO::init(InstrumentationConfig &IConf, InstrumentorIRBuilderTy &IIRB,
                  ConfigTy *UserConfig) {
  bool IsPRE = getLocationKind() == InstrumentationLocation::INSTRUCTION_PRE;
  if (UserConfig)
    Config = *UserConfig;
  if (Config.has(PassPointer)) {
    IRTArgs.push_back(
        IRTArg(IIRB.PtrTy, "pointer", "The accessed pointer.",
               ((IsPRE && Config.has(ReplacePointer)) ? IRTArg::REPLACABLE
                                                      : IRTArg::NONE),
               getPointer, setPointer));
  }
  if (Config.has(PassPointerAS)) {
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "pointer_as",
                             "The address space of the accessed pointer.",
                             IRTArg::NONE, getPointerAS));
  }
  if (Config.has(PassBasePointerInfo)) {
    IRTArgs.push_back(IRTArg(IIRB.PtrTy, "base_pointer_info",
                             "The runtime provided base pointer info.",
                             IRTArg::NONE, getBasePointerInfo));
  }
  if (!IsPRE && Config.has(PassValue)) {
    IRTArgs.push_back(
        IRTArg(getValueType(IIRB), "value", "The loaded value.",
               Config.has(ReplaceValue)
                   ? IRTArg::REPLACABLE | IRTArg::POTENTIALLY_INDIRECT |
                         (Config.has(PassValueSize) ? IRTArg::INDIRECT_HAS_SIZE
                                                    : IRTArg::NONE)
                   : IRTArg::NONE,
               getValue, Config.has(ReplaceValue) ? replaceValue : nullptr));
  }
  if (Config.has(PassValueSize)) {
    IRTArgs.push_back(IRTArg(IIRB.Int64Ty, "value_size",
                             "The size of the loaded value.", IRTArg::NONE,
                             getValueSize));
  }
  if (Config.has(PassAlignment)) {
    IRTArgs.push_back(IRTArg(IIRB.Int64Ty, "alignment",
                             "The known access alignment.", IRTArg::NONE,
                             getAlignment));
  }
  if (Config.has(PassValueTypeId)) {
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "value_type_id",
                             "The type id of the loaded value.", IRTArg::TYPEID,
                             getValueTypeId));
  }
  if (Config.has(PassValueSubTypeId)) {
    IRTArgs.push_back(IRTArg(
        IIRB.Int32Ty, "value_sub_type_id",
        "The sub type id of the loaded value (for arrays and vectors, or -1).",
        IRTArg::TYPEID, getValueSubTypeId));
  }
  if (Config.has(PassAtomicityOrdering)) {
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "atomicity_ordering",
                             "The atomicity ordering of the load.",
                             IRTArg::NONE, getAtomicityOrdering));
  }
  if (Config.has(PassSyncScopeId)) {
    IRTArgs.push_back(IRTArg(IIRB.Int8Ty, "sync_scope_id",
                             "The sync scope id of the load.", IRTArg::NONE,
                             getSyncScopeId));
  }
  if (Config.has(PassIsVolatile)) {
    IRTArgs.push_back(IRTArg(IIRB.Int8Ty, "is_volatile",
                             "Flag indicating a volatile load.", IRTArg::NONE,
                             isVolatile));
  }
 
  addCommonArgs(IConf, IIRB.Ctx, Config.has(PassId));
  IConf.addChoice(*this, IIRB.Ctx);
}
 
Value *LoadIO::getPointer(Value &V, Type &Ty, InstrumentationConfig &IConf,
                          InstrumentorIRBuilderTy &IIRB) {
  auto &LI = cast<LoadInst>(V);
  return LI.getPointerOperand();
}
 
Value *LoadIO::setPointer(Value &V, Value &NewV, InstrumentationConfig &IConf,
                          InstrumentorIRBuilderTy &IIRB) {
  auto &LI = cast<LoadInst>(V);
  LI.setOperand(LI.getPointerOperandIndex(), &NewV);
  return &LI;
}
 
Value *LoadIO::getPointerAS(Value &V, Type &Ty, InstrumentationConfig &IConf,
                            InstrumentorIRBuilderTy &IIRB) {
  auto &LI = cast<LoadInst>(V);
  return getCI(&Ty, LI.getPointerAddressSpace());
}
 
Value *LoadIO::getBasePointerInfo(Value &V, Type &Ty,
                                  InstrumentationConfig &IConf,
                                  InstrumentorIRBuilderTy &IIRB) {
  auto &LI = cast<LoadInst>(V);
  return IConf.getBasePointerInfo(*LI.getPointerOperand(), IIRB);
}
 
Value *LoadIO::getValue(Value &V, Type &Ty, InstrumentationConfig &IConf,
                        InstrumentorIRBuilderTy &IIRB) {
  return &V;
}
 
Value *LoadIO::getValueSize(Value &V, Type &Ty, InstrumentationConfig &IConf,
                            InstrumentorIRBuilderTy &IIRB) {
  auto &LI = cast<LoadInst>(V);
  auto &DL = LI.getDataLayout();
  return getCI(&Ty, DL.getTypeStoreSize(LI.getType()));
}
 
Value *LoadIO::getAlignment(Value &V, Type &Ty, InstrumentationConfig &IConf,
                            InstrumentorIRBuilderTy &IIRB) {
  auto &LI = cast<LoadInst>(V);
  return getCI(&Ty, LI.getAlign().value());
}
 
Value *LoadIO::getValueTypeId(Value &V, Type &Ty, InstrumentationConfig &IConf,
                              InstrumentorIRBuilderTy &IIRB) {
  auto &LI = cast<LoadInst>(V);
  return getCI(&Ty, LI.getType()->getTypeID());
}
 
Value *LoadIO::getValueSubTypeId(Value &V, Type &Ty,
                                 InstrumentationConfig &IConf,
                                 InstrumentorIRBuilderTy &IIRB) {
  auto &LI = cast<LoadInst>(V);
  return getSubTypeID(*LI.getType(), Ty);
}
 
Value *LoadIO::getAtomicityOrdering(Value &V, Type &Ty,
                                    InstrumentationConfig &IConf,
                                    InstrumentorIRBuilderTy &IIRB) {
  auto &LI = cast<LoadInst>(V);
  return getCI(&Ty, uint64_t(LI.getOrdering()));
}
 
Value *LoadIO::getSyncScopeId(Value &V, Type &Ty, InstrumentationConfig &IConf,
                              InstrumentorIRBuilderTy &IIRB) {
  auto &LI = cast<LoadInst>(V);
  return getCI(&Ty, uint64_t(LI.getSyncScopeID()));
}
 
Value *LoadIO::isVolatile(Value &V, Type &Ty, InstrumentationConfig &IConf,
                          InstrumentorIRBuilderTy &IIRB) {
  auto &LI = cast<LoadInst>(V);
  return getCI(&Ty, LI.isVolatile());
}
 
void BasePointerIO::init(InstrumentationConfig &IConf,
                         InstrumentorIRBuilderTy &IIRB, ConfigTy *UserConfig) {
  if (UserConfig)
    Config = *UserConfig;
  if (Config.has(PassPointer))
    IRTArgs.push_back(IRTArg(IIRB.PtrTy, "base_pointer",
                             "The base pointer in question.",
                             IRTArg::REPLACABLE, getValue, setValueNoop));
  if (Config.has(PassPointerKind))
    IRTArgs.push_back(IRTArg(
        IIRB.Int32Ty, "base_pointer_kind",
        "The base pointer kind (argument, global, instruction, unknown).",
        IRTArg::NONE, getPointerKind));
  addCommonArgs(IConf, IIRB.Ctx, Config.has(PassId));
  IConf.addChoice(*this, IIRB.Ctx);
}
 
Value *BasePointerIO::getPointerKind(Value &V, Type &Ty,
                                     InstrumentationConfig &IConf,
                                     InstrumentorIRBuilderTy &IIRB) {
  if (isa<Argument>(V))
    return getCI(&Ty, 0);
  if (isa<GlobalValue>(V))
    return getCI(&Ty, 1);
  if (isa<Instruction>(V))
    return getCI(&Ty, 2);
  return getCI(&Ty, 3);
}
 
void ModuleIO::init(InstrumentationConfig &IConf, InstrumentorIRBuilderTy &IIRB,
                    ConfigTy *UserConfig) {
  if (UserConfig)
    Config = *UserConfig;
 
  if (Config.has(PassName))
    IRTArgs.push_back(IRTArg(IIRB.PtrTy, "module_name",
                             "The module/translation unit name.",
                             IRTArg::STRING, getModuleName));
  if (Config.has(PassTargetTriple))
    IRTArgs.push_back(IRTArg(IIRB.PtrTy, "target_triple", "The target triple.",
                             IRTArg::STRING, getTargetTriple));
 
  addCommonArgs(IConf, IIRB.Ctx, Config.has(PassId));
  IConf.addChoice(*this, IIRB.Ctx);
}
Value *ModuleIO::getModuleName(Value &V, Type &Ty, InstrumentationConfig &IConf,
                               InstrumentorIRBuilderTy &IIRB) {
  // V is a constructor or destructor of the module we can place code in.
  auto &Fn = cast<Function>(V);
  return IConf.getGlobalString(Fn.getParent()->getName(), IIRB);
}
Value *ModuleIO::getTargetTriple(Value &V, Type &Ty,
                                 InstrumentationConfig &IConf,
                                 InstrumentorIRBuilderTy &IIRB) {
  // V is a constructor or destructor of the module we can place code in.
  auto &Fn = cast<Function>(V);
  return IConf.getGlobalString(Fn.getParent()->getTargetTriple().getTriple(),
                               IIRB);
}
 
void GlobalVarIO::init(InstrumentationConfig &IConf,
                       InstrumentorIRBuilderTy &IIRB, ConfigTy *UserConfig) {
  if (UserConfig)
    Config = *UserConfig;
  bool IsPRE = InstrumentationLocation::isPRE(getLocationKind());
  if (Config.has(PassAddress))
    IRTArgs.push_back(IRTArg(
        IIRB.PtrTy, "address",
        "The address of the global (replaceable for definitions).",
        IsPRE && Config.has(ReplaceAddress) ? IRTArg::REPLACABLE : IRTArg::NONE,
        getAddress, setAddress));
  if (Config.has(PassAS))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "address_space",
                             "The address space of the global.", IRTArg::NONE,
                             getAS));
  if (Config.has(PassDeclaredSize))
    IRTArgs.push_back(IRTArg(IIRB.Int64Ty, "declared_size",
                             "The size of the declared type of the global.",
                             IRTArg::NONE, getDeclaredSize));
  if (Config.has(PassAlignment))
    IRTArgs.push_back(IRTArg(IIRB.Int64Ty, "alignment",
                             "The allocation alignment.", IRTArg::NONE,
                             getAlignment));
  if (Config.has(PassName))
    IRTArgs.push_back(IRTArg(IIRB.PtrTy, "name", "The name of the global.",
                             IRTArg::STRING, getSymbolName));
  if (Config.has(PassInitialValue))
    IRTArgs.push_back(IRTArg(
        IIRB.Int64Ty, "initial_value", "The initial value of the global.",
        IRTArg::POTENTIALLY_INDIRECT | IRTArg::INDIRECT_HAS_SIZE,
        getInitialValue));
  if (Config.has(PassIsConstant))
    IRTArgs.push_back(IRTArg(IIRB.Int8Ty, "is_constant",
                             "Flag to indicate constant globals.", IRTArg::NONE,
                             isConstant));
  if (Config.has(PassIsDefinition))
    IRTArgs.push_back(IRTArg(IIRB.Int8Ty, "is_definition",
                             "Flag to indicate global definitions.",
                             IRTArg::NONE, isDefinition));
  addCommonArgs(IConf, IIRB.Ctx, Config.has(PassId));
  IConf.addChoice(*this, IIRB.Ctx);
}
Value *GlobalVarIO::getAddress(Value &V, Type &Ty, InstrumentationConfig &IConf,
                               InstrumentorIRBuilderTy &IIRB) {
  GlobalVariable &GV = cast<GlobalVariable>(V);
  if (GV.getAddressSpace())
    return ConstantExpr::getAddrSpaceCast(&GV, IIRB.PtrTy);
  return &GV;
}
Value *GlobalVarIO::setAddress(Value &V, Value &NewV,
                               InstrumentationConfig &IConf,
                               InstrumentorIRBuilderTy &IIRB) {
  GlobalVariable &GV = cast<GlobalVariable>(V);
 
  GlobalVariable *ShadowGV = nullptr;
  auto ShadowName = IConf.getRTName("shadow.", GV.getName());
  auto &DL = GV.getDataLayout();
  if (GV.isDeclaration()) {
    ShadowGV = new GlobalVariable(*GV.getParent(), GV.getType(), false,
                                  GlobalVariable::WeakODRLinkage, &GV,
                                  ShadowName, &GV, GV.getThreadLocalMode(),
                                  DL.getDefaultGlobalsAddressSpace());
  } else {
    ShadowGV = new GlobalVariable(
        *GV.getParent(), NewV.getType(), false, GV.getLinkage(),
        PoisonValue::get(NewV.getType()), ShadowName, &GV);
    IIRB.IRB.CreateStore(&NewV, ShadowGV);
  }
 
  SmallVector<Use *> Worklist(make_pointer_range(GV.uses()));
  SmallPtrSet<Use *, 32> Done;
  DenseMap<Value *, Instruction *> ConstToInstMap;
  DenseMap<Function *, Instruction *> ReloadMap;
 
  auto MakeInstForConst = [&](Use &U) {
    Instruction *&I = ConstToInstMap[U];
    if (I)
      return;
    if (U == &GV) {
    } else if (auto *CE = dyn_cast<ConstantExpr>(U)) {
      I = CE->getAsInstruction();
    }
  };
 
  auto InsertConsts = [&](Instruction *UserI, Use &UserU) {
    SmallVector<std::pair<Instruction *, Use *>> Worklist;
    auto *&Reload = ReloadMap[UserI->getFunction()];
    if (!Reload) {
      Reload = new LoadInst(
          GV.getType(), ShadowGV, GV.getName() + ".shadow_load",
          UserI->getFunction()->getEntryBlock().getFirstNonPHIOrAlloca());
      IIRB.NewInsts.insert({Reload, IIRB.Epoch});
    }
    Worklist.push_back({UserI, &UserU});
    while (!Worklist.empty()) {
      auto [I, U] = Worklist.pop_back_val();
      if (*U == &GV) {
        U->set(ReloadMap[I->getFunction()]);
        continue;
      }
      if (auto *CI = ConstToInstMap[*U]) {
        auto *CIClone = CI->clone();
        IIRB.NewInsts.insert({CIClone, IIRB.Epoch});
        if (auto *PHI = dyn_cast<PHINode>(I)) {
          auto *BB = PHI->getIncomingBlock(U->getOperandNo());
          CIClone->insertBefore(BB->getTerminator()->getIterator());
        } else {
          CIClone->insertBefore(I->getIterator());
        }
        U->set(CIClone);
        for (auto &CICUse : CIClone->operands()) {
          Worklist.push_back({CIClone, &CICUse});
        }
      }
    }
  };
 
  while (!Worklist.empty()) {
    Use *U = Worklist.pop_back_val();
    if (!Done.insert(U).second)
      continue;
    MakeInstForConst(*U);
    auto *I = dyn_cast<Instruction>(U->getUser());
    if (!I) {
      append_range(Worklist, make_pointer_range(U->getUser()->uses()));
      continue;
    }
    if (IIRB.NewInsts.lookup(I) == IIRB.Epoch)
      continue;
    if (isa<LandingPadInst>(I))
      continue;
    if (auto *II = dyn_cast<IntrinsicInst>(I))
      if (II->getIntrinsicID() == Intrinsic::eh_typeid_for)
        continue;
    if (I->getParent())
      InsertConsts(I, *U);
  }
 
  for (auto &It : ConstToInstMap)
    if (It.second)
      It.second->deleteValue();
 
  return &V;
}
Value *GlobalVarIO::getAS(Value &V, Type &Ty, InstrumentationConfig &IConf,
                          InstrumentorIRBuilderTy &IIRB) {
  GlobalVariable &GV = cast<GlobalVariable>(V);
  return getCI(&Ty, GV.getAddressSpace());
}
Value *GlobalVarIO::getAlignment(Value &V, Type &Ty,
                                 InstrumentationConfig &IConf,
                                 InstrumentorIRBuilderTy &IIRB) {
  GlobalVariable &GV = cast<GlobalVariable>(V);
  MaybeAlign Alignment = GV.getAlign();
  return getCI(&Ty, Alignment ? Alignment->value() : 0);
}
Value *GlobalVarIO::getDeclaredSize(Value &V, Type &Ty,
                                    InstrumentationConfig &IConf,
                                    InstrumentorIRBuilderTy &IIRB) {
  GlobalVariable &GV = cast<GlobalVariable>(V);
  auto &DL = GV.getDataLayout();
  return getCI(&Ty, DL.getTypeAllocSize(GV.getValueType()));
}
Value *GlobalVarIO::getSymbolName(Value &V, Type &Ty,
                                  InstrumentationConfig &IConf,
                                  InstrumentorIRBuilderTy &IIRB) {
  GlobalVariable &GV = cast<GlobalVariable>(V);
  return IConf.getGlobalString(GV.getName(), IIRB);
}
Value *GlobalVarIO::getInitialValue(Value &V, Type &Ty,
                                    InstrumentationConfig &IConf,
                                    InstrumentorIRBuilderTy &IIRB) {
  GlobalVariable &GV = cast<GlobalVariable>(V);
  return GV.hasInitializer() ? GV.getInitializer()
                             : Constant::getNullValue(&Ty);
}
Value *GlobalVarIO::isConstant(Value &V, Type &Ty, InstrumentationConfig &IConf,
                               InstrumentorIRBuilderTy &IIRB) {
  GlobalVariable &GV = cast<GlobalVariable>(V);
  return getCI(&Ty, GV.isConstant());
}
Value *GlobalVarIO::isDefinition(Value &V, Type &Ty,
                                 InstrumentationConfig &IConf,
                                 InstrumentorIRBuilderTy &IIRB) {
  GlobalVariable &GV = cast<GlobalVariable>(V);
  return getCI(&Ty, !GV.isDeclaration());
}
 
/// CastIO
/// {
void CastIO::init(InstrumentationConfig &IConf, InstrumentorIRBuilderTy &IIRB,
                  ConfigTy *UserConfig) {
  if (UserConfig)
    Config = *UserConfig;
  bool IsPRE = getLocationKind() == InstrumentationLocation::INSTRUCTION_PRE;
  if (Config.has(PassInput))
    IRTArgs.push_back(
        IRTArg(IIRB.Int64Ty, "input", "Input value of the cast.",
               IRTArg::POTENTIALLY_INDIRECT |
                   (Config.has(PassResultSize) ? IRTArg::INDIRECT_HAS_SIZE
                                               : IRTArg::NONE),
               getInput));
  if (Config.has(PassInputTypeId))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "input_type_id",
                             "The type id of the input value.", IRTArg::TYPEID,
                             getInputTypeId));
  if (Config.has(PassInputSubTypeId))
    IRTArgs.push_back(IRTArg(
        IIRB.Int32Ty, "input_sub_type_id",
        "The sub type id of the input value (for arrays and vectors, or -1).",
        IRTArg::TYPEID, getInputSubTypeId));
  if (Config.has(PassInputSize))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "input_size",
                             "The size of the input value.", IRTArg::NONE,
                             getInputSize));
  if (!IsPRE && Config.has(PassResult))
    IRTArgs.push_back(
        IRTArg(IIRB.Int64Ty, "result", "Result of the cast.",
               (IRTArg::REPLACABLE | IRTArg::POTENTIALLY_INDIRECT) |
                   (Config.has(PassResultSize) ? IRTArg::INDIRECT_HAS_SIZE
                                               : IRTArg::NONE),
               getValue, Config.has(ReplaceResult) ? replaceValue : nullptr));
  if (Config.has(PassResultTypeId))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "result_type_id",
                             "The type id of the result value.", IRTArg::TYPEID,
                             getResultTypeId));
  if (Config.has(PassResultSubTypeId))
    IRTArgs.push_back(IRTArg(
        IIRB.Int32Ty, "result_sub_type_id",
        "The sub type id of the result value (for arrays and vectors, or -1).",
        IRTArg::TYPEID, getResultSubTypeId));
  if (Config.has(PassResultSize))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "result_size",
                             "The size of the result value.", IRTArg::NONE,
                             getResultSize));
  if (Config.has(PassOpcode))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "opcode",
                             "The opcode of the cast instruction.",
                             IRTArg::NONE, getOpcode));
 
  addCommonArgs(IConf, IIRB.Ctx, Config.has(PassId));
  IConf.addChoice(*this, IIRB.Ctx);
}
 
Value *CastIO::getInput(Value &V, Type &Ty, InstrumentationConfig &IConf,
                        InstrumentorIRBuilderTy &IIRB) {
  auto &CI = cast<CastInst>(V);
  return CI.getOperand(0);
}
 
Value *CastIO::getInputTypeId(Value &V, Type &Ty, InstrumentationConfig &IConf,
                              InstrumentorIRBuilderTy &IIRB) {
  auto &CI = cast<CastInst>(V);
  return getCI(&Ty, CI.getSrcTy()->getTypeID());
}
 
Value *CastIO::getInputSubTypeId(Value &V, Type &Ty,
                                 InstrumentationConfig &IConf,
                                 InstrumentorIRBuilderTy &IIRB) {
  auto &CI = cast<CastInst>(V);
  return getSubTypeID(*CI.getSrcTy(), Ty);
}
 
Value *CastIO::getInputSize(Value &V, Type &Ty, InstrumentationConfig &IConf,
                            InstrumentorIRBuilderTy &IIRB) {
  auto &CI = cast<CastInst>(V);
  auto &DL = CI.getDataLayout();
  return getCI(&Ty, DL.getTypeStoreSize(CI.getSrcTy()));
}
 
Value *CastIO::getResultTypeId(Value &V, Type &Ty, InstrumentationConfig &IConf,
                               InstrumentorIRBuilderTy &IIRB) {
  auto &CI = cast<CastInst>(V);
  return getCI(&Ty, CI.getDestTy()->getTypeID());
}
 
Value *CastIO::getResultSubTypeId(Value &V, Type &Ty,
                                  InstrumentationConfig &IConf,
                                  InstrumentorIRBuilderTy &IIRB) {
  auto &CI = cast<CastInst>(V);
  return getSubTypeID(*CI.getDestTy(), Ty);
}
 
Value *CastIO::getResultSize(Value &V, Type &Ty, InstrumentationConfig &IConf,
                             InstrumentorIRBuilderTy &IIRB) {
  auto &CI = cast<CastInst>(V);
  auto &DL = CI.getDataLayout();
  return getCI(&Ty, DL.getTypeStoreSize(CI.getDestTy()));
}
///}
 
Value *NumericIO::getFlags(Value &V, Type &Ty, InstrumentationConfig &IConf,
                           InstrumentorIRBuilderTy &IIRB) {
  auto &I = cast<Instruction>(V);
  uint64_t Flag = NUMERIC_FLAG_NONE;
 
  switch (I.getOpcode()) {
  case Instruction::Add:
  case Instruction::Sub:
  case Instruction::Mul:
  case Instruction::Shl:
    if (I.hasNoSignedWrap())
      Flag |= NUMERIC_FLAG_NO_SIGNED_WRAP;
    if (I.hasNoUnsignedWrap())
      Flag |= NUMERIC_FLAG_NO_UNSIGNED_WRAP;
    break;
  case Instruction::FAdd:
  case Instruction::FSub:
  case Instruction::FMul:
  case Instruction::FDiv:
  case Instruction::FNeg:
    if (I.hasNoNaNs())
      Flag |= NUMERIC_FLAG_HAS_NO_NANS;
    if (I.hasNoInfs())
      Flag |= NUMERIC_FLAG_HAS_NO_INFS;
    if (I.hasNoSignedZeros())
      Flag |= NUMERIC_FLAG_HAS_NO_SIGNED_ZEROS;
    break;
  case Instruction::AShr:
  case Instruction::LShr:
  case Instruction::SDiv:
  case Instruction::UDiv:
    if (I.isExact())
      Flag |= NUMERIC_FLAG_IS_EXACT;
    break;
  }
 
  if (auto *DI = dyn_cast<PossiblyDisjointInst>(&V))
    if (DI->isDisjoint())
      Flag |= NUMERIC_FLAG_IS_DISJOINT;
 
  return getCI(&Ty, Flag);
}
 
void NumericIO::addFlagNames() {
  FlagNames["nsw"] = NUMERIC_FLAG_NO_SIGNED_WRAP;
  FlagNames["nuw"] = NUMERIC_FLAG_NO_UNSIGNED_WRAP;
  FlagNames["nnan"] = NUMERIC_FLAG_HAS_NO_NANS;
  FlagNames["ninf"] = NUMERIC_FLAG_HAS_NO_INFS;
  FlagNames["nsz"] = NUMERIC_FLAG_HAS_NO_SIGNED_ZEROS;
  FlagNames["exact"] = NUMERIC_FLAG_IS_EXACT;
}
 
void NumericIO::init(InstrumentationConfig &IConf,
                     InstrumentorIRBuilderTy &IIRB, ConfigTy *UserConfig) {
  if (UserConfig)
    Config = UserConfig;
  bool IsPRE = getLocationKind() == InstrumentationLocation::INSTRUCTION_PRE;
  const auto ValArgOpts =
      IRTArg::POTENTIALLY_INDIRECT |
      (Config.has(PassSize) ? IRTArg::INDIRECT_HAS_SIZE : IRTArg::NONE);
  if (Config.has(PassTypeId))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "type_id",
                             "The operation's type id.", IRTArg::TYPEID,
                             getTypeId));
  if (Config.has(PassSubTypeId))
    IRTArgs.push_back(
        IRTArg(IIRB.Int32Ty, "sub_type_id",
               "The operation's sub type id (for arrays and vectors, or -1).",
               IRTArg::TYPEID, getSubTypeId));
  if (Config.has(PassSize))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "size", "The operation's type size.",
                             IRTArg::NONE, getTypeSize));
  if (Config.has(PassOpcode))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "opcode", "The instruction opcode.",
                             IRTArg::NONE, getOpcode));
  if (Config.has(PassLeft))
    IRTArgs.push_back(IRTArg(IIRB.Int64Ty, "left",
                             "The operation's left operand.", ValArgOpts,
                             getLeftOperand));
  if (Config.has(PassRight))
    IRTArgs.push_back(IRTArg(IIRB.Int64Ty, "right",
                             "The operation's right operand. This value is "
                             "poison for unary operations.",
                             ValArgOpts, getRightOperand));
  if (!IsPRE && Config.has(PassResult))
    IRTArgs.push_back(
        IRTArg(IIRB.Int64Ty, "result", "Result of the operation.",
               IRTArg::REPLACABLE | ValArgOpts, getValue,
               Config.has(ReplaceResult) ? replaceValue : nullptr));
  if (Config.has(PassFlags))
    IRTArgs.push_back(
        IRTArg(IIRB.Int64Ty, "flags",
               "A bitmask value signaling which instruction flags are present.",
               IRTArg::NONE, getFlags));
  addCommonArgs(IConf, IIRB.Ctx, Config.has(PassId));
  addFlagNames();
  IConf.addChoice(*this, IIRB.Ctx);
}
 
Value *CompareIO::getOperandTypeId(Value &V, Type &Ty,
                                   InstrumentationConfig &IConf,
                                   InstrumentorIRBuilderTy &IIRB) {
  auto &I = cast<Instruction>(V);
  return getCI(&Ty, I.getOperand(0)->getType()->getTypeID());
}
 
Value *CompareIO::getOperandSize(Value &V, Type &Ty,
                                 InstrumentationConfig &IConf,
                                 InstrumentorIRBuilderTy &IIRB) {
  auto &I = cast<Instruction>(V);
  auto &DL = I.getDataLayout();
  return getCI(&Ty, DL.getTypeStoreSize(I.getOperand(0)->getType()));
}
 
Value *CompareIO::getPredicate(Value &V, Type &Ty, InstrumentationConfig &IConf,
                               InstrumentorIRBuilderTy &IIRB) {
  auto *CI = dyn_cast<CmpInst>(&V);
  return getCI(&Ty, CI->getPredicate());
}
 
void CompareIO::addFlagNames() {
  FlagNames["samesign"] = COMPARE_FLAG_SAMESIGN;
  FlagNames["nnan"] = COMPARE_FLAG_HAS_NO_NANS;
  FlagNames["ninf"] = COMPARE_FLAG_HAS_NO_INFS;
  FlagNames["nsz"] = COMPARE_FLAG_HAS_NO_SIGNED_ZEROS;
}
 
Value *CompareIO::getFlags(Value &V, Type &Ty, InstrumentationConfig &IConf,
                           InstrumentorIRBuilderTy &IIRB) {
  auto &I = cast<Instruction>(V);
  uint64_t Flag = NUMERIC_FLAG_NONE;
 
  switch (I.getOpcode()) {
  case Instruction::ICmp:
    if (dyn_cast<ICmpInst>(&V)->hasSameSign())
      Flag |= COMPARE_FLAG_SAMESIGN;
    break;
  case Instruction::FCmp:
    if (I.hasNoNaNs())
      Flag |= COMPARE_FLAG_HAS_NO_NANS;
    if (I.hasNoInfs())
      Flag |= COMPARE_FLAG_HAS_NO_INFS;
    if (I.hasNoSignedZeros())
      Flag |= COMPARE_FLAG_HAS_NO_SIGNED_ZEROS;
    break;
  }
 
  return getCI(&Ty, Flag);
}
 
void CompareIO::init(InstrumentationConfig &IConf,
                     InstrumentorIRBuilderTy &IIRB, ConfigTy *UserConfig) {
  if (UserConfig)
    Config = UserConfig;
  bool IsPRE = getLocationKind() == InstrumentationLocation::INSTRUCTION_PRE;
  const auto OperandArgOpts =
      IRTArg::POTENTIALLY_INDIRECT |
      (Config.has(PassOpSize) ? IRTArg::INDIRECT_HAS_SIZE : IRTArg::NONE);
  if (Config.has(PassOpTypeId))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "operand_type_id",
                             "The operand type id.", IRTArg::NONE,
                             getOperandTypeId));
  if (Config.has(PassOpSize))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "operand_size",
                             "The operand type size.", IRTArg::NONE,
                             getOperandSize));
  if (Config.has(PassOpcode))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "opcode", "The instruction opcode.",
                             IRTArg::NONE, getOpcode));
  if (Config.has(PassPredicate))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "predicate",
                             "The comparison predicate ID.", IRTArg::NONE,
                             getPredicate));
  if (Config.has(PassLeft))
    IRTArgs.push_back(IRTArg(IIRB.Int64Ty, "left",
                             "The comparison's left operand.", OperandArgOpts,
                             getLeftOperand));
  if (Config.has(PassRight))
    IRTArgs.push_back(IRTArg(IIRB.Int64Ty, "right",
                             "The comparison's right operand.", OperandArgOpts,
                             getRightOperand));
  if (!IsPRE && Config.has(PassResultSize))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "result_type_id",
                             "The result value's type ID.", IRTArg::NONE,
                             getTypeId));
  if (!IsPRE && Config.has(PassResultSize))
    IRTArgs.push_back(IRTArg(IIRB.Int32Ty, "result_size",
                             "Size of the result value.", IRTArg::NONE,
                             getTypeSize));
  if (!IsPRE && Config.has(PassResult))
    IRTArgs.push_back(
        IRTArg(IIRB.Int64Ty, "result", "Result of the operation.",
               IRTArg::REPLACABLE | IRTArg::POTENTIALLY_INDIRECT |
                   (Config.has(PassResultSize) ? IRTArg::INDIRECT_HAS_SIZE
                                               : IRTArg::NONE),
               getValue, Config.has(ReplaceResult) ? replaceValue : nullptr));
  if (Config.has(PassFlags))
    IRTArgs.push_back(
        IRTArg(IIRB.Int64Ty, "flags",
               "A bitmask value signaling which instruction flags are present.",
               IRTArg::NONE, getFlags));
  addFlagNames();
  addCommonArgs(IConf, IIRB.Ctx, Config.has(PassId));
  IConf.addChoice(*this, IIRB.Ctx);
}