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/Analysis/Passes.h"
19 #include "llvm/ADT/Statistic.h"
20 #include "llvm/IR/DebugInfo.h"
21 #include "llvm/IR/Function.h"
22 #include "llvm/Pass.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/raw_ostream.h"
25 using namespace llvm;
26 
27 namespace {
28   class ModuleDebugInfoPrinter : public ModulePass {
29     DebugInfoFinder Finder;
30   public:
31     static char ID; // Pass identification, replacement for typeid
ModuleDebugInfoPrinter()32     ModuleDebugInfoPrinter() : ModulePass(ID) {
33       initializeModuleDebugInfoPrinterPass(*PassRegistry::getPassRegistry());
34     }
35 
36     bool runOnModule(Module &M) override;
37 
getAnalysisUsage(AnalysisUsage & AU) const38     void getAnalysisUsage(AnalysisUsage &AU) const override {
39       AU.setPreservesAll();
40     }
41     void print(raw_ostream &O, const Module *M) const override;
42   };
43 }
44 
45 char ModuleDebugInfoPrinter::ID = 0;
46 INITIALIZE_PASS(ModuleDebugInfoPrinter, "module-debuginfo",
47                 "Decodes module-level debug info", false, true)
48 
createModuleDebugInfoPrinterPass()49 ModulePass *llvm::createModuleDebugInfoPrinterPass() {
50   return new ModuleDebugInfoPrinter();
51 }
52 
runOnModule(Module & M)53 bool ModuleDebugInfoPrinter::runOnModule(Module &M) {
54   Finder.processModule(M);
55   return false;
56 }
57 
printFile(raw_ostream & O,StringRef Filename,StringRef Directory,unsigned Line=0)58 static void printFile(raw_ostream &O, StringRef Filename, StringRef Directory,
59                       unsigned Line = 0) {
60   if (Filename.empty())
61     return;
62 
63   O << " from ";
64   if (!Directory.empty())
65     O << Directory << "/";
66   O << Filename;
67   if (Line)
68     O << ":" << Line;
69 }
70 
print(raw_ostream & O,const Module * M) const71 void ModuleDebugInfoPrinter::print(raw_ostream &O, const Module *M) const {
72   // Printing the nodes directly isn't particularly helpful (since they
73   // reference other nodes that won't be printed, particularly for the
74   // filenames), so just print a few useful things.
75   for (DICompileUnit *CU : Finder.compile_units()) {
76     O << "Compile unit: ";
77     if (const char *Lang = dwarf::LanguageString(CU->getSourceLanguage()))
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 (const DIGlobalVariable *GV : Finder.global_variables()) {
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       if (const char *Encoding =
109               dwarf::AttributeEncodingString(BT->getEncoding()))
110         O << Encoding;
111       else
112         O << "unknown-encoding(" << BT->getEncoding() << ')';
113     } else {
114       O << ' ';
115       if (const char *Tag = dwarf::TagString(T->getTag()))
116         O << Tag;
117       else
118         O << "unknown-tag(" << T->getTag() << ")";
119     }
120     if (auto *CT = dyn_cast<DICompositeType>(T)) {
121       if (auto *S = CT->getRawIdentifier())
122         O << " (identifier: '" << S->getString() << "')";
123     }
124     O << '\n';
125   }
126 }
127