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/BinaryFormat/Dwarf.h"
19#include "llvm/IR/DebugInfo.h"
20#include "llvm/IR/PassManager.h"
21#include "llvm/Pass.h"
22#include "llvm/Support/ErrorHandling.h"
23#include "llvm/Support/raw_ostream.h"
24using namespace llvm;
25
26static void printFile(raw_ostream &O, StringRef Filename, StringRef Directory,
27 unsigned Line = 0) {
28 if (Filename.empty())
29 return;
30
31 O << " from ";
32 if (!Directory.empty())
33 O << Directory << "/";
34 O << Filename;
35 if (Line)
36 O << ":" << Line;
37}
38
39static void printModuleDebugInfo(raw_ostream &O, const Module *M,
40 const DebugInfoFinder &Finder) {
41 // Printing the nodes directly isn't particularly helpful (since they
42 // reference other nodes that won't be printed, particularly for the
43 // filenames), so just print a few useful things.
44 for (DICompileUnit *CU : Finder.compile_units()) {
45 O << "Compile unit: ";
46 auto Lang = dwarf::LanguageString(Language: CU->getSourceLanguage());
47 if (!Lang.empty())
48 O << Lang;
49 else
50 O << "unknown-language(" << CU->getSourceLanguage() << ")";
51 printFile(O, Filename: CU->getFilename(), Directory: CU->getDirectory());
52 O << '\n';
53 }
54
55 for (DISubprogram *S : Finder.subprograms()) {
56 O << "Subprogram: " << S->getName();
57 printFile(O, Filename: S->getFilename(), Directory: S->getDirectory(), Line: S->getLine());
58 if (!S->getLinkageName().empty())
59 O << " ('" << S->getLinkageName() << "')";
60 O << '\n';
61 }
62
63 for (auto *GVU : Finder.global_variables()) {
64 const auto *GV = GVU->getVariable();
65 O << "Global variable: " << GV->getName();
66 printFile(O, Filename: GV->getFilename(), Directory: GV->getDirectory(), Line: GV->getLine());
67 if (!GV->getLinkageName().empty())
68 O << " ('" << GV->getLinkageName() << "')";
69 O << '\n';
70 }
71
72 for (const DIType *T : Finder.types()) {
73 O << "Type:";
74 if (!T->getName().empty())
75 O << ' ' << T->getName();
76 printFile(O, Filename: T->getFilename(), Directory: T->getDirectory(), Line: T->getLine());
77 if (auto *BT = dyn_cast<DIBasicType>(Val: T)) {
78 O << " ";
79 auto Encoding = dwarf::AttributeEncodingString(Encoding: BT->getEncoding());
80 if (!Encoding.empty())
81 O << Encoding;
82 else
83 O << "unknown-encoding(" << BT->getEncoding() << ')';
84 } else {
85 O << ' ';
86 auto Tag = dwarf::TagString(Tag: T->getTag());
87 if (!Tag.empty())
88 O << Tag;
89 else
90 O << "unknown-tag(" << T->getTag() << ")";
91 }
92 if (auto *CT = dyn_cast<DICompositeType>(Val: T)) {
93 if (auto *S = CT->getRawIdentifier())
94 O << " (identifier: '" << S->getString() << "')";
95 }
96 O << '\n';
97 }
98}
99
100ModuleDebugInfoPrinterPass::ModuleDebugInfoPrinterPass(raw_ostream &OS)
101 : OS(OS) {}
102
103PreservedAnalyses ModuleDebugInfoPrinterPass::run(Module &M,
104 ModuleAnalysisManager &AM) {
105 Finder.processModule(M);
106 printModuleDebugInfo(O&: OS, M: &M, Finder);
107 return PreservedAnalyses::all();
108}
109