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/BinaryFormat/Dwarf.h"
  19 #include "llvm/IR/DebugInfo.h"
  20 #include "llvm/IR/PassManager.h"
  21 #include "llvm/Pass.h"
  22 #include "llvm/Support/ErrorHandling.h"
  23 #include "llvm/Support/raw_ostream.h"
  24 using namespace llvm;
  25
  26 static void printFile(raw_ostream &O, StringRef Filename, StringRef Directory,
  27                       unsigned Line = 0) {
  28   if (Filename.empty())
  29     return;
  30
  31   O << " from ";
  32   if (!Directory.empty())
  33     O << Directory << "/";
  34   O << Filename;
  35   if (Line)
  36     O << ":" << Line;
  37 }
  38
  39 static void printModuleDebugInfo(raw_ostream &O, const Module *M,
  40                                  const DebugInfoFinder &Finder) {
  41   // Printing the nodes directly isn't particularly helpful (since they
  42   // reference other nodes that won't be printed, particularly for the
  43   // filenames), so just print a few useful things.
  44   for (DICompileUnit *CU : Finder.compile_units()) {
  45     O << "Compile unit: ";
  46     auto Lang = dwarf::LanguageString(CU->getSourceLanguage());
  47     if (!Lang.empty())
  48       O << Lang;
  49     else
  50       O << "unknown-language(" << CU->getSourceLanguage() << ")";
  51     printFile(O, CU->getFilename(), CU->getDirectory());
  52     O << '\n';
  53   }
  54
  55   for (DISubprogram *S : Finder.subprograms()) {
  56     O << "Subprogram: " << S->getName();
  57     printFile(O, S->getFilename(), S->getDirectory(), S->getLine());
  58     if (!S->getLinkageName().empty())
  59       O << " ('" << S->getLinkageName() << "')";
  60     O << '\n';
  61   }
  62
  63   for (auto *GVU : Finder.global_variables()) {
  64     const auto *GV = GVU->getVariable();
  65     O << "Global variable: " << GV->getName();
  66     printFile(O, GV->getFilename(), GV->getDirectory(), GV->getLine());
  67     if (!GV->getLinkageName().empty())
  68       O << " ('" << GV->getLinkageName() << "')";
  69     O << '\n';
  70   }
  71
  72   for (const DIType *T : Finder.types()) {
  73     O << "Type:";
  74     if (!T->getName().empty())
  75       O << ' ' << T->getName();
  76     printFile(O, T->getFilename(), T->getDirectory(), T->getLine());
  77     if (auto *BT = dyn_cast<DIBasicType>(T)) {
  78       O << " ";
  79       auto Encoding = dwarf::AttributeEncodingString(BT->getEncoding());
  80       if (!Encoding.empty())
  81         O << Encoding;
  82       else
  83         O << "unknown-encoding(" << BT->getEncoding() << ')';
  84     } else {
  85       O << ' ';
  86       auto Tag = dwarf::TagString(T->getTag());
  87       if (!Tag.empty())
  88         O << Tag;
  89       else
  90         O << "unknown-tag(" << T->getTag() << ")";
  91     }
  92     if (auto *CT = dyn_cast<DICompositeType>(T)) {
  93       if (auto *S = CT->getRawIdentifier())
  94         O << " (identifier: '" << S->getString() << "')";
  95     }
  96     O << '\n';
  97   }
  98 }
  99
 100 ModuleDebugInfoPrinterPass::ModuleDebugInfoPrinterPass(raw_ostream &OS)
 101     : OS(OS) {}
 102
 103 PreservedAnalyses ModuleDebugInfoPrinterPass::run(Module &M,
 104                                                   ModuleAnalysisManager &AM) {
 105   Finder.processModule(M);
 106   printModuleDebugInfo(OS, &M, Finder);
 107   return PreservedAnalyses::all();
 108 }