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/ADT/Statistic.h"
  19 #include "llvm/Analysis/Passes.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 namespace {
  29 class ModuleDebugInfoLegacyPrinter : public ModulePass {
  30   DebugInfoFinder Finder;
  31
  32 public:
  33   static char ID; // Pass identification, replacement for typeid
  34   ModuleDebugInfoLegacyPrinter() : ModulePass(ID) {
  35     initializeModuleDebugInfoLegacyPrinterPass(
  36         *PassRegistry::getPassRegistry());
  37   }
  38
  39   bool runOnModule(Module &M) override;
  40
  41   void getAnalysisUsage(AnalysisUsage &AU) const override {
  42     AU.setPreservesAll();
  43   }
  44   void print(raw_ostream &O, const Module *M) const override;
  45 };
  46 }
  47
  48 char ModuleDebugInfoLegacyPrinter::ID = 0;
  49 INITIALIZE_PASS(ModuleDebugInfoLegacyPrinter, "module-debuginfo",
  50                 "Decodes module-level debug info", false, true)
  51
  52 ModulePass *llvm::createModuleDebugInfoPrinterPass() {
  53   return new ModuleDebugInfoLegacyPrinter();
  54 }
  55
  56 bool ModuleDebugInfoLegacyPrinter::runOnModule(Module &M) {
  57   Finder.processModule(M);
  58   return false;
  59 }
  60
  61 static void printFile(raw_ostream &O, StringRef Filename, StringRef Directory,
  62                       unsigned Line = 0) {
  63   if (Filename.empty())
  64     return;
  65
  66   O << " from ";
  67   if (!Directory.empty())
  68     O << Directory << "/";
  69   O << Filename;
  70   if (Line)
  71     O << ":" << Line;
  72 }
  73
  74 static void printModuleDebugInfo(raw_ostream &O, const Module *M,
  75                                  const DebugInfoFinder &Finder) {
  76   // Printing the nodes directly isn't particularly helpful (since they
  77   // reference other nodes that won't be printed, particularly for the
  78   // filenames), so just print a few useful things.
  79   for (DICompileUnit *CU : Finder.compile_units()) {
  80     O << "Compile unit: ";
  81     auto Lang = dwarf::LanguageString(CU->getSourceLanguage());
  82     if (!Lang.empty())
  83       O << Lang;
  84     else
  85       O << "unknown-language(" << CU->getSourceLanguage() << ")";
  86     printFile(O, CU->getFilename(), CU->getDirectory());
  87     O << '\n';
  88   }
  89
  90   for (DISubprogram *S : Finder.subprograms()) {
  91     O << "Subprogram: " << S->getName();
  92     printFile(O, S->getFilename(), S->getDirectory(), S->getLine());
  93     if (!S->getLinkageName().empty())
  94       O << " ('" << S->getLinkageName() << "')";
  95     O << '\n';
  96   }
  97
  98   for (auto GVU : Finder.global_variables()) {
  99     const auto *GV = GVU->getVariable();
 100     O << "Global variable: " << GV->getName();
 101     printFile(O, GV->getFilename(), GV->getDirectory(), GV->getLine());
 102     if (!GV->getLinkageName().empty())
 103       O << " ('" << GV->getLinkageName() << "')";
 104     O << '\n';
 105   }
 106
 107   for (const DIType *T : Finder.types()) {
 108     O << "Type:";
 109     if (!T->getName().empty())
 110       O << ' ' << T->getName();
 111     printFile(O, T->getFilename(), T->getDirectory(), T->getLine());
 112     if (auto *BT = dyn_cast<DIBasicType>(T)) {
 113       O << " ";
 114       auto Encoding = dwarf::AttributeEncodingString(BT->getEncoding());
 115       if (!Encoding.empty())
 116         O << Encoding;
 117       else
 118         O << "unknown-encoding(" << BT->getEncoding() << ')';
 119     } else {
 120       O << ' ';
 121       auto Tag = dwarf::TagString(T->getTag());
 122       if (!Tag.empty())
 123         O << Tag;
 124       else
 125         O << "unknown-tag(" << T->getTag() << ")";
 126     }
 127     if (auto *CT = dyn_cast<DICompositeType>(T)) {
 128       if (auto *S = CT->getRawIdentifier())
 129         O << " (identifier: '" << S->getString() << "')";
 130     }
 131     O << '\n';
 132   }
 133 }
 134
 135 void ModuleDebugInfoLegacyPrinter::print(raw_ostream &O,
 136                                          const Module *M) const {
 137   printModuleDebugInfo(O, M, Finder);
 138 }
 139
 140 ModuleDebugInfoPrinterPass::ModuleDebugInfoPrinterPass(raw_ostream &OS)
 141     : OS(OS) {}
 142
 143 PreservedAnalyses ModuleDebugInfoPrinterPass::run(Module &M,
 144                                                   ModuleAnalysisManager &AM) {
 145   Finder.processModule(M);
 146   printModuleDebugInfo(OS, &M, Finder);
 147   return PreservedAnalyses::all();
 148 }