//===- FunctionIndexObjectFile.cpp - Function index file implementation ---===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Part of the FunctionIndexObjectFile class implementation.
//
//===----------------------------------------------------------------------===//

#include "llvm/Object/FunctionIndexObjectFile.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/IR/FunctionInfo.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
using namespace object;

FunctionIndexObjectFile::FunctionIndexObjectFile(
    MemoryBufferRef Object, std::unique_ptr<FunctionInfoIndex> I)
    : SymbolicFile(Binary::ID_FunctionIndex, Object), Index(std::move(I)) {}

FunctionIndexObjectFile::~FunctionIndexObjectFile() {}

std::unique_ptr<FunctionInfoIndex> FunctionIndexObjectFile::takeIndex() {
  return std::move(Index);
}

ErrorOr<MemoryBufferRef>
FunctionIndexObjectFile::findBitcodeInObject(const ObjectFile &Obj) {
  for (const SectionRef &Sec : Obj.sections()) {
    StringRef SecName;
    if (std::error_code EC = Sec.getName(SecName))
      return EC;
    if (SecName == ".llvmbc") {
      StringRef SecContents;
      if (std::error_code EC = Sec.getContents(SecContents))
        return EC;
      return MemoryBufferRef(SecContents, Obj.getFileName());
    }
  }

  return object_error::bitcode_section_not_found;
}

ErrorOr<MemoryBufferRef>
FunctionIndexObjectFile::findBitcodeInMemBuffer(MemoryBufferRef Object) {
  sys::fs::file_magic Type = sys::fs::identify_magic(Object.getBuffer());
  switch (Type) {
  case sys::fs::file_magic::bitcode:
    return Object;
  case sys::fs::file_magic::elf_relocatable:
  case sys::fs::file_magic::macho_object:
  case sys::fs::file_magic::coff_object: {
    ErrorOr<std::unique_ptr<ObjectFile>> ObjFile =
        ObjectFile::createObjectFile(Object, Type);
    if (!ObjFile)
      return ObjFile.getError();
    return findBitcodeInObject(*ObjFile->get());
  }
  default:
    return object_error::invalid_file_type;
  }
}

// Looks for function index in the given memory buffer.
// returns true if found, else false.
bool FunctionIndexObjectFile::hasFunctionSummaryInMemBuffer(
    MemoryBufferRef Object, DiagnosticHandlerFunction DiagnosticHandler) {
  ErrorOr<MemoryBufferRef> BCOrErr = findBitcodeInMemBuffer(Object);
  if (!BCOrErr)
    return false;

  return hasFunctionSummary(BCOrErr.get(), DiagnosticHandler);
}

// Parse function index in the given memory buffer.
// Return new FunctionIndexObjectFile instance containing parsed
// function summary/index.
ErrorOr<std::unique_ptr<FunctionIndexObjectFile>>
FunctionIndexObjectFile::create(MemoryBufferRef Object,
                                DiagnosticHandlerFunction DiagnosticHandler,
                                bool IsLazy) {
  std::unique_ptr<FunctionInfoIndex> Index;

  ErrorOr<MemoryBufferRef> BCOrErr = findBitcodeInMemBuffer(Object);
  if (!BCOrErr)
    return BCOrErr.getError();

  ErrorOr<std::unique_ptr<FunctionInfoIndex>> IOrErr = getFunctionInfoIndex(
      BCOrErr.get(), DiagnosticHandler, IsLazy);

  if (std::error_code EC = IOrErr.getError())
    return EC;

  Index = std::move(IOrErr.get());

  return llvm::make_unique<FunctionIndexObjectFile>(Object, std::move(Index));
}

// Parse the function summary information for function with the
// given name out of the given buffer. Parsed information is
// stored on the index object saved in this object.
std::error_code FunctionIndexObjectFile::findFunctionSummaryInMemBuffer(
    MemoryBufferRef Object, DiagnosticHandlerFunction DiagnosticHandler,
    StringRef FunctionName) {
  sys::fs::file_magic Type = sys::fs::identify_magic(Object.getBuffer());
  switch (Type) {
  case sys::fs::file_magic::bitcode: {
    return readFunctionSummary(Object, DiagnosticHandler, FunctionName,
                               std::move(Index));
  }
  default:
    return object_error::invalid_file_type;
  }
}

// Parse the function index out of an IR file and return the function
// index object if found, or nullptr if not.
ErrorOr<std::unique_ptr<FunctionInfoIndex>>
llvm::getFunctionIndexForFile(StringRef Path,
                              DiagnosticHandlerFunction DiagnosticHandler) {
  ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
      MemoryBuffer::getFileOrSTDIN(Path);
  std::error_code EC = FileOrErr.getError();
  if (EC)
    return EC;
  MemoryBufferRef BufferRef = (FileOrErr.get())->getMemBufferRef();
  ErrorOr<std::unique_ptr<object::FunctionIndexObjectFile>> ObjOrErr =
      object::FunctionIndexObjectFile::create(BufferRef, DiagnosticHandler);
  EC = ObjOrErr.getError();
  if (EC)
    return EC;

  object::FunctionIndexObjectFile &Obj = **ObjOrErr;
  return Obj.takeIndex();
}