llvm/lib/Analysis/ModuleDebugInfoPrinter.cpp

//===-- ModuleDebugInfoPrinter.cpp - Prints module debug info metadata ----===//
//
// 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 pass decodes the debug info metadata in a module and prints in a
// (sufficiently-prepared-) human-readable form.
//
// For example, run this pass from opt along with the -analyze option, and
// it'll print to standard output.
//
//===----------------------------------------------------------------------===//

#include "llvm/Analysis/ModuleDebugInfoPrinter.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;

static void printFile(raw_ostream &O, StringRef Filename, StringRef Directory,
                      unsigned Line = 0) {
  if (Filename.empty())
    return;

  O << " from ";
  if (!Directory.empty())
    O << Directory << "/";
  O << Filename;
  if (Line)
    O << ":" << Line;
}

static void printModuleDebugInfo(raw_ostream &O, const Module *M,
                                 const DebugInfoFinder &Finder) {
  // Printing the nodes directly isn't particularly helpful (since they
  // reference other nodes that won't be printed, particularly for the
  // filenames), so just print a few useful things.
  for (DICompileUnit *CU : Finder.compile_units()) {
    O << "Compile unit: ";

    DISourceLanguageName Lang = CU->getSourceLanguage();
    auto LangStr =
        Lang.hasVersionedName()
            ? dwarf::SourceLanguageNameString(
                  static_cast<llvm::dwarf::SourceLanguageName>(Lang.getName()))
            : dwarf::LanguageString(Lang.getName());

    if (!LangStr.empty())
      O << LangStr;
    else
      O << "unknown-language(" << CU->getSourceLanguage().getName() << ")";

    printFile(O, CU->getFilename(), CU->getDirectory());
    O << '\n';
  }

  for (DISubprogram *S : Finder.subprograms()) {
    O << "Subprogram: " << S->getName();
    printFile(O, S->getFilename(), S->getDirectory(), S->getLine());
    if (!S->getLinkageName().empty())
      O << " ('" << S->getLinkageName() << "')";
    O << '\n';
  }

  for (auto *GVU : Finder.global_variables()) {
    const auto *GV = GVU->getVariable();
    O << "Global variable: " << GV->getName();
    printFile(O, GV->getFilename(), GV->getDirectory(), GV->getLine());
    if (!GV->getLinkageName().empty())
      O << " ('" << GV->getLinkageName() << "')";
    O << '\n';
  }

  for (const DIType *T : Finder.types()) {
    O << "Type:";
    if (!T->getName().empty())
      O << ' ' << T->getName();
    printFile(O, T->getFilename(), T->getDirectory(), T->getLine());
    if (auto *BT = dyn_cast<DIBasicType>(T)) {
      O << " ";
      auto Encoding = dwarf::AttributeEncodingString(BT->getEncoding());
      if (!Encoding.empty())
        O << Encoding;
      else
        O << "unknown-encoding(" << BT->getEncoding() << ')';
    } else {
      O << ' ';
      auto Tag = dwarf::TagString(T->getTag());
      if (!Tag.empty())
        O << Tag;
      else
        O << "unknown-tag(" << T->getTag() << ")";
    }
    if (auto *CT = dyn_cast<DICompositeType>(T)) {
      if (auto *S = CT->getRawIdentifier())
        O << " (identifier: '" << S->getString() << "')";
    }
    O << '\n';
  }

  for (const auto &MacroEntry : Finder.macros()) {
    const DIMacro *Macro = MacroEntry.first;
    const DIMacroFile *MacroFile = MacroEntry.second;

    O << "Macro: ";
    auto MacroType = dwarf::MacinfoString(Macro->getMacinfoType());
    if (!MacroType.empty())
      O << MacroType;
    else
      O << "unknown-macinfo(" << Macro->getMacinfoType() << ")";

    O << " '" << Macro->getName() << "'";
    if (!Macro->getValue().empty())
      O << " = '" << Macro->getValue() << "'";

    if (MacroFile && MacroFile->getFile()) {
      const DIFile *File = MacroFile->getFile();
      printFile(O, File->getFilename(), File->getDirectory(),
                MacroFile->getLine());
    } else {
      O << " at line " << Macro->getLine();
    }
    O << '\n';
  }
}

ModuleDebugInfoPrinterPass::ModuleDebugInfoPrinterPass(raw_ostream &OS)
    : OS(OS) {}

PreservedAnalyses ModuleDebugInfoPrinterPass::run(Module &M,
                                                  ModuleAnalysisManager &AM) {
  Finder.processModule(M);
  printModuleDebugInfo(OS, &M, Finder);
  return PreservedAnalyses::all();
}