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/ADT/Statistic.h"
  18 #include "llvm/Analysis/Passes.h"
  19 #include "llvm/IR/DebugInfo.h"
  20 #include "llvm/Pass.h"
  21 #include "llvm/Support/ErrorHandling.h"
  22 #include "llvm/Support/raw_ostream.h"
  23 using namespace llvm;
  24
  25 namespace {
  26   class ModuleDebugInfoPrinter : public ModulePass {
  27     DebugInfoFinder Finder;
  28   public:
  29     static char ID; // Pass identification, replacement for typeid
  30     ModuleDebugInfoPrinter() : ModulePass(ID) {
  31       initializeModuleDebugInfoPrinterPass(*PassRegistry::getPassRegistry());
  32     }
  33
  34     bool runOnModule(Module &M) override;
  35
  36     void getAnalysisUsage(AnalysisUsage &AU) const override {
  37       AU.setPreservesAll();
  38     }
  39     void print(raw_ostream &O, const Module *M) const override;
  40   };
  41 }
  42
  43 char ModuleDebugInfoPrinter::ID = 0;
  44 INITIALIZE_PASS(ModuleDebugInfoPrinter, "module-debuginfo",
  45                 "Decodes module-level debug info", false, true)
  46
  47 ModulePass *llvm::createModuleDebugInfoPrinterPass() {
  48   return new ModuleDebugInfoPrinter();
  49 }
  50
  51 bool ModuleDebugInfoPrinter::runOnModule(Module &M) {
  52   Finder.processModule(M);
  53   return false;
  54 }
  55
  56 static void printFile(raw_ostream &O, StringRef Filename, StringRef Directory,
  57                       unsigned Line = 0) {
  58   if (Filename.empty())
  59     return;
  60
  61   O << " from ";
  62   if (!Directory.empty())
  63     O << Directory << "/";
  64   O << Filename;
  65   if (Line)
  66     O << ":" << Line;
  67 }
  68
  69 void ModuleDebugInfoPrinter::print(raw_ostream &O, const Module *M) const {
  70   // Printing the nodes directly isn't particularly helpful (since they
  71   // reference other nodes that won't be printed, particularly for the
  72   // filenames), so just print a few useful things.
  73   for (DICompileUnit *CU : Finder.compile_units()) {
  74     O << "Compile unit: ";
  75     auto Lang = dwarf::LanguageString(CU->getSourceLanguage());
  76     if (!Lang.empty())
  77       O << Lang;
  78     else
  79       O << "unknown-language(" << CU->getSourceLanguage() << ")";
  80     printFile(O, CU->getFilename(), CU->getDirectory());
  81     O << '\n';
  82   }
  83
  84   for (DISubprogram *S : Finder.subprograms()) {
  85     O << "Subprogram: " << S->getName();
  86     printFile(O, S->getFilename(), S->getDirectory(), S->getLine());
  87     if (!S->getLinkageName().empty())
  88       O << " ('" << S->getLinkageName() << "')";
  89     O << '\n';
  90   }
  91
  92   for (auto GVU : Finder.global_variables()) {
  93     const auto *GV = GVU->getVariable();
  94     O << "Global variable: " << GV->getName();
  95     printFile(O, GV->getFilename(), GV->getDirectory(), GV->getLine());
  96     if (!GV->getLinkageName().empty())
  97       O << " ('" << GV->getLinkageName() << "')";
  98     O << '\n';
  99   }
 100
 101   for (const DIType *T : Finder.types()) {
 102     O << "Type:";
 103     if (!T->getName().empty())
 104       O << ' ' << T->getName();
 105     printFile(O, T->getFilename(), T->getDirectory(), T->getLine());
 106     if (auto *BT = dyn_cast<DIBasicType>(T)) {
 107       O << " ";
 108       auto Encoding = dwarf::AttributeEncodingString(BT->getEncoding());
 109       if (!Encoding.empty())
 110         O << Encoding;
 111       else
 112         O << "unknown-encoding(" << BT->getEncoding() << ')';
 113     } else {
 114       O << ' ';
 115       auto Tag = dwarf::TagString(T->getTag());
 116       if (!Tag.empty())
 117         O << Tag;
 118       else
 119         O << "unknown-tag(" << T->getTag() << ")";
 120     }
 121     if (auto *CT = dyn_cast<DICompositeType>(T)) {
 122       if (auto *S = CT->getRawIdentifier())
 123         O << " (identifier: '" << S->getString() << "')";
 124     }
 125     O << '\n';
 126   }
 127 }