llvm/lib/Analysis/ModuleDebugInfoPrinter.cpp

   1 //===-- ModuleDebugInfoPrinter.cpp - Prints module debug info metadata ----===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This pass decodes the debug info metadata in a module and prints in a
  10 // (sufficiently-prepared-) human-readable form.
  11 //
  12 // For example, run this pass from opt along with the -analyze option, and
  13 // it'll print to standard output.
  14 //
  15 //===----------------------------------------------------------------------===//
  16
  17 #include "llvm/Analysis/ModuleDebugInfoPrinter.h"
  18 #include "llvm/Analysis/Passes.h"
  19 #include "llvm/BinaryFormat/Dwarf.h"
  20 #include "llvm/IR/DebugInfo.h"
  21 #include "llvm/IR/PassManager.h"
  22 #include "llvm/InitializePasses.h"
  23 #include "llvm/Pass.h"
  24 #include "llvm/Support/ErrorHandling.h"
  25 #include "llvm/Support/raw_ostream.h"
  26 using namespace llvm;
  27
  28 static void printFile(raw_ostream &O, StringRef Filename, StringRef Directory,
  29                       unsigned Line = 0) {
  30   if (Filename.empty())
  31     return;
  32
  33   O << " from ";
  34   if (!Directory.empty())
  35     O << Directory << "/";
  36   O << Filename;
  37   if (Line)
  38     O << ":" << Line;
  39 }
  40
  41 static void printModuleDebugInfo(raw_ostream &O, const Module *M,
  42                                  const DebugInfoFinder &Finder) {
  43   // Printing the nodes directly isn't particularly helpful (since they
  44   // reference other nodes that won't be printed, particularly for the
  45   // filenames), so just print a few useful things.
  46   for (DICompileUnit *CU : Finder.compile_units()) {
  47     O << "Compile unit: ";
  48     auto Lang = dwarf::LanguageString(CU->getSourceLanguage());
  49     if (!Lang.empty())
  50       O << Lang;
  51     else
  52       O << "unknown-language(" << CU->getSourceLanguage() << ")";
  53     printFile(O, CU->getFilename(), CU->getDirectory());
  54     O << '\n';
  55   }
  56
  57   for (DISubprogram *S : Finder.subprograms()) {
  58     O << "Subprogram: " << S->getName();
  59     printFile(O, S->getFilename(), S->getDirectory(), S->getLine());
  60     if (!S->getLinkageName().empty())
  61       O << " ('" << S->getLinkageName() << "')";
  62     O << '\n';
  63   }
  64
  65   for (auto *GVU : Finder.global_variables()) {
  66     const auto *GV = GVU->getVariable();
  67     O << "Global variable: " << GV->getName();
  68     printFile(O, GV->getFilename(), GV->getDirectory(), GV->getLine());
  69     if (!GV->getLinkageName().empty())
  70       O << " ('" << GV->getLinkageName() << "')";
  71     O << '\n';
  72   }
  73
  74   for (const DIType *T : Finder.types()) {
  75     O << "Type:";
  76     if (!T->getName().empty())
  77       O << ' ' << T->getName();
  78     printFile(O, T->getFilename(), T->getDirectory(), T->getLine());
  79     if (auto *BT = dyn_cast<DIBasicType>(T)) {
  80       O << " ";
  81       auto Encoding = dwarf::AttributeEncodingString(BT->getEncoding());
  82       if (!Encoding.empty())
  83         O << Encoding;
  84       else
  85         O << "unknown-encoding(" << BT->getEncoding() << ')';
  86     } else {
  87       O << ' ';
  88       auto Tag = dwarf::TagString(T->getTag());
  89       if (!Tag.empty())
  90         O << Tag;
  91       else
  92         O << "unknown-tag(" << T->getTag() << ")";
  93     }
  94     if (auto *CT = dyn_cast<DICompositeType>(T)) {
  95       if (auto *S = CT->getRawIdentifier())
  96         O << " (identifier: '" << S->getString() << "')";
  97     }
  98     O << '\n';
  99   }
 100 }
 101
 102 ModuleDebugInfoPrinterPass::ModuleDebugInfoPrinterPass(raw_ostream &OS)
 103     : OS(OS) {}
 104
 105 PreservedAnalyses ModuleDebugInfoPrinterPass::run(Module &M,
 106                                                   ModuleAnalysisManager &AM) {
 107   Finder.processModule(M);
 108   printModuleDebugInfo(OS, &M, Finder);
 109   return PreservedAnalyses::all();
 110 }