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/Analysis/Passes.h"
19#include "llvm/BinaryFormat/Dwarf.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"
26using namespace llvm;
27
28static void printFile(raw_ostream &O, StringRef Filename, StringRef Directory,
29 unsigned Line = 0) {
30 if (Filename.empty())
31 return;
32
33 O << " from ";
34 if (!Directory.empty())
35 O << Directory << "/";
36 O << Filename;
37 if (Line)
38 O << ":" << Line;
39}
40
41static void printModuleDebugInfo(raw_ostream &O, const Module *M,
42 const DebugInfoFinder &Finder) {
43 // Printing the nodes directly isn't particularly helpful (since they
44 // reference other nodes that won't be printed, particularly for the
45 // filenames), so just print a few useful things.
46 for (DICompileUnit *CU : Finder.compile_units()) {
47 O << "Compile unit: ";
48 auto Lang = dwarf::LanguageString(Language: CU->getSourceLanguage());
49 if (!Lang.empty())
50 O << Lang;
51 else
52 O << "unknown-language(" << CU->getSourceLanguage() << ")";
53 printFile(O, Filename: CU->getFilename(), Directory: CU->getDirectory());
54 O << '\n';
55 }
56
57 for (DISubprogram *S : Finder.subprograms()) {
58 O << "Subprogram: " << S->getName();
59 printFile(O, Filename: S->getFilename(), Directory: S->getDirectory(), Line: S->getLine());
60 if (!S->getLinkageName().empty())
61 O << " ('" << S->getLinkageName() << "')";
62 O << '\n';
63 }
64
65 for (auto *GVU : Finder.global_variables()) {
66 const auto *GV = GVU->getVariable();
67 O << "Global variable: " << GV->getName();
68 printFile(O, Filename: GV->getFilename(), Directory: GV->getDirectory(), Line: GV->getLine());
69 if (!GV->getLinkageName().empty())
70 O << " ('" << GV->getLinkageName() << "')";
71 O << '\n';
72 }
73
74 for (const DIType *T : Finder.types()) {
75 O << "Type:";
76 if (!T->getName().empty())
77 O << ' ' << T->getName();
78 printFile(O, Filename: T->getFilename(), Directory: T->getDirectory(), Line: T->getLine());
79 if (auto *BT = dyn_cast<DIBasicType>(Val: T)) {
80 O << " ";
81 auto Encoding = dwarf::AttributeEncodingString(Encoding: BT->getEncoding());
82 if (!Encoding.empty())
83 O << Encoding;
84 else
85 O << "unknown-encoding(" << BT->getEncoding() << ')';
86 } else {
87 O << ' ';
88 auto Tag = dwarf::TagString(Tag: T->getTag());
89 if (!Tag.empty())
90 O << Tag;
91 else
92 O << "unknown-tag(" << T->getTag() << ")";
93 }
94 if (auto *CT = dyn_cast<DICompositeType>(Val: T)) {
95 if (auto *S = CT->getRawIdentifier())
96 O << " (identifier: '" << S->getString() << "')";
97 }
98 O << '\n';
99 }
100}
101
102ModuleDebugInfoPrinterPass::ModuleDebugInfoPrinterPass(raw_ostream &OS)
103 : OS(OS) {}
104
105PreservedAnalyses ModuleDebugInfoPrinterPass::run(Module &M,
106 ModuleAnalysisManager &AM) {
107 Finder.processModule(M);
108 printModuleDebugInfo(O&: OS, M: &M, Finder);
109 return PreservedAnalyses::all();
110}
111