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 }
149