//===-- IntelJITEventListener.cpp - Tell Intel profiler about JITed code --===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file defines a JITEventListener object to tell Intel(R) VTune(TM)
// Amplifier XE 2011 about JITted functions.
//
//===----------------------------------------------------------------------===//

#include "IntelJITEventsWrapper.h"
#include "ittnotify.h"
#include "llvm-c/ExecutionEngine.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/Config/config.h"
#include "llvm/DebugInfo/DIContext.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/ExecutionEngine/JITEventListener.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Object/ELFObjectFile.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Object/SymbolSize.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Errno.h"
#include "llvm/Support/raw_ostream.h"

using namespace llvm;
using namespace llvm::object;

#define DEBUG_TYPE "amplifier-jit-event-listener"

namespace {

class IntelIttnotifyInfo {
  std::string ModuleName;
  std::vector<std::string> SectionNamesVector;
  std::vector<__itt_section_info> SectionInfoVector;
  __itt_module_object *ModuleObject;
  IntelJITEventsWrapper &WrapperRef;

public:
  IntelIttnotifyInfo(IntelJITEventsWrapper &Wrapper)
      : ModuleObject(NULL), WrapperRef(Wrapper){};
  ~IntelIttnotifyInfo() { delete ModuleObject; };

  void setModuleName(const char *Name) { ModuleName = std::string(Name); }

  const char *getModuleName() { return ModuleName.c_str(); }

  void setModuleObject(__itt_module_object *ModuleObj) {
    ModuleObject = ModuleObj;
  }

  __itt_module_object *getModuleObject() { return ModuleObject; }

  __itt_section_info *getSectionInfoVectorBegin() {
    if (SectionInfoVector.size())
      return &SectionInfoVector[0];
    return NULL;
  }

  void reportSection(llvm::IttEventType EventType, const char *SectionName,
                     unsigned int SectionSize) {
    WrapperRef.iJitIttNotifyInfo(EventType, SectionName, SectionSize);
  }

  int fillSectionInformation(const ObjectFile &Obj,
                             const RuntimeDyld::LoadedObjectInfo &L) {

    int SectionCounter = 0;

    for (auto &Section : Obj.sections()) {
      uint64_t SectionLoadAddr = L.getSectionLoadAddress(Section);
      if (SectionLoadAddr) {
        object::ELFSectionRef ElfSection(Section);

        __itt_section_info SectionInfo;
        memset(&SectionInfo, 0, sizeof(SectionInfo));
        SectionInfo.start_addr = reinterpret_cast<void *>(SectionLoadAddr);
        SectionInfo.file_offset = ElfSection.getOffset();
        SectionInfo.flags = ElfSection.getFlags();

        StringRef SectionName("");
        auto SectionNameOrError = ElfSection.getName();
        if (SectionNameOrError)
          SectionName = *SectionNameOrError;

        SectionNamesVector.push_back(SectionName.str());
        SectionInfo.size = ElfSection.getSize();
        reportSection(llvm::LoadBinarySection, SectionName.str().c_str(),
                      SectionInfo.size);

        if (ElfSection.isBSS()) {
          SectionInfo.type = itt_section_type_bss;
        } else if (ElfSection.isData()) {
          SectionInfo.type = itt_section_type_data;
        } else if (ElfSection.isText()) {
          SectionInfo.type = itt_section_type_text;
        }
        SectionInfoVector.push_back(SectionInfo);
        ++SectionCounter;
      }
    }
    // Hereinafter: don't change SectionNamesVector content to avoid vector
    // reallocation - reallocation invalidates all the references, pointers, and
    // iterators referring to the elements in the sequence.
    for (int I = 0; I < SectionCounter; ++I) {
      SectionInfoVector[I].name = SectionNamesVector[I].c_str();
    }
    return SectionCounter;
  }
};

class IntelJITEventListener : public JITEventListener {
  typedef DenseMap<void*, unsigned int> MethodIDMap;

  std::unique_ptr<IntelJITEventsWrapper> Wrapper;
  MethodIDMap MethodIDs;

  typedef SmallVector<const void *, 64> MethodAddressVector;
  typedef DenseMap<const void *, MethodAddressVector>  ObjectMap;

  ObjectMap  LoadedObjectMap;
  std::map<ObjectKey, OwningBinary<ObjectFile>> DebugObjects;

  std::map<ObjectKey, std::unique_ptr<IntelIttnotifyInfo>> KeyToIttnotify;

public:
  IntelJITEventListener(IntelJITEventsWrapper* libraryWrapper) {
      Wrapper.reset(libraryWrapper);
  }

  ~IntelJITEventListener() {
  }

  void notifyObjectLoaded(ObjectKey Key, const ObjectFile &Obj,
                          const RuntimeDyld::LoadedObjectInfo &L) override;

  void notifyFreeingObject(ObjectKey Key) override;
};

static LineNumberInfo DILineInfoToIntelJITFormat(uintptr_t StartAddress,
                                                 uintptr_t Address,
                                                 DILineInfo Line) {
  LineNumberInfo Result;

  Result.Offset = Address - StartAddress;
  Result.LineNumber = Line.Line;

  return Result;
}

static iJIT_Method_Load FunctionDescToIntelJITFormat(
    IntelJITEventsWrapper& Wrapper,
    const char* FnName,
    uintptr_t FnStart,
    size_t FnSize) {
  iJIT_Method_Load Result;
  memset(&Result, 0, sizeof(iJIT_Method_Load));

  Result.method_id = Wrapper.iJIT_GetNewMethodID();
  Result.method_name = const_cast<char*>(FnName);
  Result.method_load_address = reinterpret_cast<void*>(FnStart);
  Result.method_size = FnSize;

  Result.class_id = 0;
  Result.class_file_name = NULL;
  Result.user_data = NULL;
  Result.user_data_size = 0;
  Result.env = iJDE_JittingAPI;

  return Result;
}

int getBackwardCompatibilityMode() {

  char *BackwardCompatibilityEnv = getenv("INTEL_JIT_BACKWARD_COMPATIBILITY");
  int BackwardCompatibilityMode = 0;
  if (BackwardCompatibilityEnv) {
    StringRef(BackwardCompatibilityEnv)
        .getAsInteger(10, BackwardCompatibilityMode);
  }
  return BackwardCompatibilityMode;
}

void IntelJITEventListener::notifyObjectLoaded(
    ObjectKey Key, const ObjectFile &Obj,
    const RuntimeDyld::LoadedObjectInfo &L) {

  int BackwardCompatibilityMode = getBackwardCompatibilityMode();
  if (BackwardCompatibilityMode == 0) {
    if (Obj.isELF()) {
      std::unique_ptr<IntelIttnotifyInfo> ModuleIttnotify =
          std::make_unique<IntelIttnotifyInfo>(*Wrapper);
      ModuleIttnotify->setModuleName(
          StringRef(llvm::utohexstr(
                        MD5Hash(Obj.getMemoryBufferRef().getBuffer()), true))
              .str()
              .c_str());

      __itt_module_object *ModuleObject = new __itt_module_object();
      ModuleObject->module_name = ModuleIttnotify->getModuleName();
      ModuleObject->module_size = Obj.getMemoryBufferRef().getBufferSize();
      Wrapper->iJitIttNotifyInfo(llvm::LoadBinaryModule,
                                 ModuleObject->module_name,
                                 ModuleObject->module_size);
      ModuleObject->module_type = __itt_module_type_elf;
      ModuleObject->section_number =
          ModuleIttnotify->fillSectionInformation(Obj, L);
      ModuleObject->module_buffer =
          (void *)const_cast<char *>(Obj.getMemoryBufferRef().getBufferStart());
      ModuleObject->module_id =
          __itt_id_make((void *)&(*ModuleObject), ModuleObject->module_size);
      ModuleObject->section_array =
          ModuleIttnotify->getSectionInfoVectorBegin();
      ModuleIttnotify->setModuleObject(ModuleObject);

      __itt_module_load_with_sections(ModuleObject);

      KeyToIttnotify[Key] = std::move(ModuleIttnotify);
    }
  } else if (BackwardCompatibilityMode == 1) {

    OwningBinary<ObjectFile> DebugObjOwner = L.getObjectForDebug(Obj);
    const ObjectFile *DebugObj = DebugObjOwner.getBinary();
    if (!DebugObj)
      return;

    // Get the address of the object image for use as a unique identifier
    const void *ObjData = DebugObj->getData().data();
    std::unique_ptr<DIContext> Context = DWARFContext::create(*DebugObj);
    MethodAddressVector Functions;

    // Use symbol info to iterate functions in the object.
    for (const std::pair<SymbolRef, uint64_t> &P :
         computeSymbolSizes(*DebugObj)) {
      SymbolRef Sym = P.first;
      std::vector<LineNumberInfo> LineInfo;
      std::string SourceFileName;

      Expected<SymbolRef::Type> SymTypeOrErr = Sym.getType();
      if (!SymTypeOrErr) {
        // TODO: Actually report errors helpfully.
        consumeError(SymTypeOrErr.takeError());
        continue;
      }
      SymbolRef::Type SymType = *SymTypeOrErr;
      if (SymType != SymbolRef::ST_Function)
        continue;

      Expected<StringRef> Name = Sym.getName();
      if (!Name) {
        // TODO: Actually report errors helpfully.
        consumeError(Name.takeError());
        continue;
      }

      Expected<uint64_t> AddrOrErr = Sym.getAddress();
      if (!AddrOrErr) {
        // TODO: Actually report errors helpfully.
        consumeError(AddrOrErr.takeError());
        continue;
      }
      uint64_t Addr = *AddrOrErr;
      uint64_t Size = P.second;

      auto SecOrErr = Sym.getSection();
      if (!SecOrErr) {
        // TODO: Actually report errors helpfully.
        consumeError(SecOrErr.takeError());
        continue;
      }
      object::section_iterator Sec = *SecOrErr;
      if (Sec == Obj.section_end())
        continue;
      uint64_t Index = Sec->getIndex();

      // Record this address in a local vector
      Functions.push_back((void *)Addr);

      // Build the function loaded notification message
      iJIT_Method_Load FunctionMessage =
          FunctionDescToIntelJITFormat(*Wrapper, Name->data(), Addr, Size);
      DILineInfoTable Lines =
          Context->getLineInfoForAddressRange({Addr, Index}, Size);
      DILineInfoTable::iterator Begin = Lines.begin();
      DILineInfoTable::iterator End = Lines.end();
      for (DILineInfoTable::iterator It = Begin; It != End; ++It) {
        LineInfo.push_back(
            DILineInfoToIntelJITFormat((uintptr_t)Addr, It->first, It->second));
      }
      if (LineInfo.size() == 0) {
        FunctionMessage.source_file_name = 0;
        FunctionMessage.line_number_size = 0;
        FunctionMessage.line_number_table = 0;
      } else {
        // Source line information for the address range is provided as
        // a code offset for the start of the corresponding sub-range and
        // a source line. JIT API treats offsets in LineNumberInfo structures
        // as the end of the corresponding code region. The start of the code
        // is taken from the previous element. Need to shift the elements.

        LineNumberInfo last = LineInfo.back();
        last.Offset = FunctionMessage.method_size;
        LineInfo.push_back(last);
        for (size_t i = LineInfo.size() - 2; i > 0; --i)
          LineInfo[i].LineNumber = LineInfo[i - 1].LineNumber;

        SourceFileName = Lines.front().second.FileName;
        FunctionMessage.source_file_name =
            const_cast<char *>(SourceFileName.c_str());
        FunctionMessage.line_number_size = LineInfo.size();
        FunctionMessage.line_number_table = &*LineInfo.begin();
      }

      Wrapper->iJIT_NotifyEvent(iJVM_EVENT_TYPE_METHOD_LOAD_FINISHED,
                                &FunctionMessage);
      MethodIDs[(void *)Addr] = FunctionMessage.method_id;
    }

    // To support object unload notification, we need to keep a list of
    // registered function addresses for each loaded object.  We will
    // use the MethodIDs map to get the registered ID for each function.
    LoadedObjectMap[ObjData] = Functions;
    DebugObjects[Key] = std::move(DebugObjOwner);
  }
}

void IntelJITEventListener::notifyFreeingObject(ObjectKey Key) {

  int BackwardCompatibilityMode = getBackwardCompatibilityMode();
  if (BackwardCompatibilityMode == 0) {
    if (KeyToIttnotify.find(Key) == KeyToIttnotify.end())
      return;
    __itt_module_unload_with_sections(KeyToIttnotify[Key]->getModuleObject());
    Wrapper->iJitIttNotifyInfo(
        llvm::UnloadBinaryModule,
        KeyToIttnotify[Key]->getModuleObject()->module_name,
        KeyToIttnotify[Key]->getModuleObject()->module_size);
    KeyToIttnotify.erase(Key);
  } else if (BackwardCompatibilityMode == 1) {
    // This object may not have been registered with the listener. If it wasn't,
    // bail out.
    if (DebugObjects.find(Key) == DebugObjects.end())
      return;

    // Get the address of the object image for use as a unique identifier
    const ObjectFile &DebugObj = *DebugObjects[Key].getBinary();
    const void *ObjData = DebugObj.getData().data();

    // Get the object's function list from LoadedObjectMap
    ObjectMap::iterator OI = LoadedObjectMap.find(ObjData);
    if (OI == LoadedObjectMap.end())
      return;
    MethodAddressVector &Functions = OI->second;

    // Walk the function list, unregistering each function
    for (MethodAddressVector::iterator FI = Functions.begin(),
                                       FE = Functions.end();
         FI != FE; ++FI) {
      void *FnStart = const_cast<void *>(*FI);
      MethodIDMap::iterator MI = MethodIDs.find(FnStart);
      if (MI != MethodIDs.end()) {
        Wrapper->iJIT_NotifyEvent(iJVM_EVENT_TYPE_METHOD_UNLOAD_START,
                                  &MI->second);
        MethodIDs.erase(MI);
      }
    }

    // Erase the object from LoadedObjectMap
    LoadedObjectMap.erase(OI);
    DebugObjects.erase(Key);
  }
}

}  // anonymous namespace.

namespace llvm {
JITEventListener *JITEventListener::createIntelJITEventListener() {
  return new IntelJITEventListener(new IntelJITEventsWrapper);
}

// for testing
JITEventListener *JITEventListener::createIntelJITEventListener(
                                      IntelJITEventsWrapper* TestImpl) {
  return new IntelJITEventListener(TestImpl);
}

} // namespace llvm

LLVMJITEventListenerRef LLVMCreateIntelJITEventListener(void)
{
  return wrap(JITEventListener::createIntelJITEventListener());
}