lib/Analysis/ModuleDebugInfoPrinter.cpp

   1 //===-- ModuleDebugInfoPrinter.cpp - Prints module debug info metadata ----===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This pass decodes the debug info metadata in a module and prints in a
  11 // (sufficiently-prepared-) human-readable form.
  12 //
  13 // For example, run this pass from opt along with the -analyze option, and
  14 // it'll print to standard output.
  15 //
  16 //===----------------------------------------------------------------------===//
  17
  18 #include "llvm/ADT/Statistic.h"
  19 #include "llvm/Analysis/Passes.h"
  20 #include "llvm/IR/DebugInfo.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 namespace {
  27   class ModuleDebugInfoPrinter : public ModulePass {
  28     DebugInfoFinder Finder;
  29   public:
  30     static char ID; // Pass identification, replacement for typeid
  31     ModuleDebugInfoPrinter() : ModulePass(ID) {
  32       initializeModuleDebugInfoPrinterPass(*PassRegistry::getPassRegistry());
  33     }
  34
  35     bool runOnModule(Module &M) override;
  36
  37     void getAnalysisUsage(AnalysisUsage &AU) const override {
  38       AU.setPreservesAll();
  39     }
  40     void print(raw_ostream &O, const Module *M) const override;
  41   };
  42 }
  43
  44 char ModuleDebugInfoPrinter::ID = 0;
  45 INITIALIZE_PASS(ModuleDebugInfoPrinter, "module-debuginfo",
  46                 "Decodes module-level debug info", false, true)
  47
  48 ModulePass *llvm::createModuleDebugInfoPrinterPass() {
  49   return new ModuleDebugInfoPrinter();
  50 }
  51
  52 bool ModuleDebugInfoPrinter::runOnModule(Module &M) {
  53   Finder.processModule(M);
  54   return false;
  55 }
  56
  57 static void printFile(raw_ostream &O, StringRef Filename, StringRef Directory,
  58                       unsigned Line = 0) {
  59   if (Filename.empty())
  60     return;
  61
  62   O << " from ";
  63   if (!Directory.empty())
  64     O << Directory << "/";
  65   O << Filename;
  66   if (Line)
  67     O << ":" << Line;
  68 }
  69
  70 void ModuleDebugInfoPrinter::print(raw_ostream &O, const Module *M) const {
  71   // Printing the nodes directly isn't particularly helpful (since they
  72   // reference other nodes that won't be printed, particularly for the
  73   // filenames), so just print a few useful things.
  74   for (DICompileUnit *CU : Finder.compile_units()) {
  75     O << "Compile unit: ";
  76     auto Lang = dwarf::LanguageString(CU->getSourceLanguage());
  77     if (!Lang.empty())
  78       O << Lang;
  79     else
  80       O << "unknown-language(" << CU->getSourceLanguage() << ")";
  81     printFile(O, CU->getFilename(), CU->getDirectory());
  82     O << '\n';
  83   }
  84
  85   for (DISubprogram *S : Finder.subprograms()) {
  86     O << "Subprogram: " << S->getName();
  87     printFile(O, S->getFilename(), S->getDirectory(), S->getLine());
  88     if (!S->getLinkageName().empty())
  89       O << " ('" << S->getLinkageName() << "')";
  90     O << '\n';
  91   }
  92
  93   for (auto GVU : Finder.global_variables()) {
  94     const auto *GV = GVU->getVariable();
  95     O << "Global variable: " << GV->getName();
  96     printFile(O, GV->getFilename(), GV->getDirectory(), GV->getLine());
  97     if (!GV->getLinkageName().empty())
  98       O << " ('" << GV->getLinkageName() << "')";
  99     O << '\n';
 100   }
 101
 102   for (const DIType *T : Finder.types()) {
 103     O << "Type:";
 104     if (!T->getName().empty())
 105       O << ' ' << T->getName();
 106     printFile(O, T->getFilename(), T->getDirectory(), T->getLine());
 107     if (auto *BT = dyn_cast<DIBasicType>(T)) {
 108       O << " ";
 109       auto Encoding = dwarf::AttributeEncodingString(BT->getEncoding());
 110       if (!Encoding.empty())
 111         O << Encoding;
 112       else
 113         O << "unknown-encoding(" << BT->getEncoding() << ')';
 114     } else {
 115       O << ' ';
 116       auto Tag = dwarf::TagString(T->getTag());
 117       if (!Tag.empty())
 118         O << Tag;
 119       else
 120         O << "unknown-tag(" << T->getTag() << ")";
 121     }
 122     if (auto *CT = dyn_cast<DICompositeType>(T)) {
 123       if (auto *S = CT->getRawIdentifier())
 124         O << " (identifier: '" << S->getString() << "')";
 125     }
 126     O << '\n';
 127   }
 128 }