llvm-project/llvm/lib/DebugInfo/LogicalView/Core/LVReader.cpp

//===-- LVReader.cpp ------------------------------------------------------===//
//
// 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 implements the LVReader class.
//
//===----------------------------------------------------------------------===//

#include "llvm/DebugInfo/LogicalView/Core/LVReader.h"
#include "llvm/DebugInfo/LogicalView/Core/LVLine.h"
#include "llvm/DebugInfo/LogicalView/Core/LVScope.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FormatAdapters.h"
#include "llvm/Support/FormatVariadic.h"
#include <tuple>

using namespace llvm;
using namespace llvm::logicalview;

#define DEBUG_TYPE "Reader"

//===----------------------------------------------------------------------===//
// Class to represent a split context.
//===----------------------------------------------------------------------===//
Error LVSplitContext::createSplitFolder(StringRef Where) {
  // The 'location' will represent the root directory for the output created
  // by the context. It will contain the different CUs files, that will be
  // extracted from a single ELF.
  Location = std::string(Where);

  // Add a trailing slash, if there is none.
  size_t Pos = Location.find_last_of('/');
  if (Location.length() != Pos + 1)
    Location.append("/");

  // Make sure the new directory exists, creating it if necessary.
  if (std::error_code EC = llvm::sys::fs::create_directories(Location))
    return createStringError(EC, "Error: could not create directory %s",
                             Location.c_str());

  return Error::success();
}

std::error_code LVSplitContext::open(std::string ContextName,
                                     std::string Extension, raw_ostream &OS) {
  assert(OutputFile == nullptr && "OutputFile already set.");

  // Transforms '/', '\', '.', ':' into '_'.
  std::string Name(flattenedFilePath(ContextName));
  Name.append(Extension);
  // Add the split context location folder name.
  if (!Location.empty())
    Name.insert(0, Location);

  std::error_code EC;
  OutputFile = std::make_unique<ToolOutputFile>(Name, EC, sys::fs::OF_None);
  if (EC)
    return EC;

  // Don't remove output file.
  OutputFile->keep();
  return std::error_code();
}

LVReader *CurrentReader = nullptr;
LVReader &LVReader::getInstance() {
  if (CurrentReader)
    return *CurrentReader;
  outs() << "Invalid instance reader.\n";
  llvm_unreachable("Invalid instance reader.");
}
void LVReader::setInstance(LVReader *Reader) { CurrentReader = Reader; }

Error LVReader::createSplitFolder() {
  if (OutputSplit) {
    // If the '--output=split' was specified, but no '--split-folder'
    // option, use the input file as base for the split location.
    if (options().getOutputFolder().empty())
      options().setOutputFolder(getFilename().str() + "_cus");

    SmallString<128> SplitFolder;
    SplitFolder = options().getOutputFolder();
    sys::fs::make_absolute(SplitFolder);

    // Return error if unable to create a split context location.
    if (Error Err = SplitContext.createSplitFolder(SplitFolder))
      return Err;

    OS << "\nSplit View Location: '" << SplitContext.getLocation() << "'\n";
  }

  return Error::success();
}

// Get the filename for given object.
StringRef LVReader::getFilename(LVObject *Object, size_t Index) const {
  if (CompileUnits.size()) {
    // Get Compile Unit for the given object.
    LVCompileUnits::const_iterator Iter =
        std::prev(CompileUnits.lower_bound(Object->getOffset()));
    if (Iter != CompileUnits.end())
      return Iter->second->getFilename(Index);
  }

  return CompileUnit ? CompileUnit->getFilename(Index) : StringRef();
}

// The Reader is the module that creates the logical view using the debug
// information contained in the binary file specified in the command line.
// This is the main entry point for the Reader and performs the following
// steps:
// - Process any patterns collected from the '--select' options.
// - For each compile unit in the debug information:
//   * Create the logical elements (scopes, symbols, types, lines).
//   * Collect debug ranges and debug locations.
//   * Move the collected logical lines to their associated scopes.
// - Once all the compile units have been processed, traverse the scopes
//   tree in order to:
//   * Calculate symbol coverage.
//   * Detect invalid ranges and locations.
//   * "resolve" the logical elements. During this pass, the names and
//      file information are updated, to reflect any dependency with other
//     logical elements.
Error LVReader::doLoad() {
  // Set current Reader instance.
  setInstance(this);

  // Delegate the scope tree creation to the specific reader.
  if (Error Err = createScopes())
    return Err;

  // As the elements can depend on elements from a different compile unit,
  // information such as name and file/line source information needs to be
  // updated.
  Root->resolveElements();

  sortScopes();
  return Error::success();
}

// Default handler for a generic reader.
Error LVReader::doPrint() {
  // Set current Reader instance.
  setInstance(this);

  return printScopes();
}

Error LVReader::printScopes() {
  if (bool DoPrint = options().getPrintExecute()) {
    if (Error Err = createSplitFolder())
      return Err;

    // Start printing from the root.
    bool DoMatch = false;
    return Root->doPrint(OutputSplit, DoMatch, DoPrint, OS);
  }

  return Error::success();
}

Error LVReader::printMatchedElements(bool UseMatchedElements) {
  if (Error Err = createSplitFolder())
    return Err;

  return Root->doPrintMatches(OutputSplit, OS, UseMatchedElements);
}

void LVReader::print(raw_ostream &OS) const {
  OS << "LVReader\n";
  LLVM_DEBUG(dbgs() << "PrintReader\n");
}