1 //===-- llvm-dis.cpp - The low-level LLVM disassembler --------------------===//
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 utility may be invoked in the following manner:
10 //  llvm-dis [options]      - Read LLVM bitcode from stdin, write asm to stdout
11 //  llvm-dis [options] x.bc - Read LLVM bitcode from the x.bc file, write asm
12 //                            to the x.ll file.
13 //  Options:
14 //      --help   - Output information about command line switches
15 //
16 //===----------------------------------------------------------------------===//
17 
18 #include "llvm/Bitcode/BitcodeReader.h"
19 #include "llvm/IR/AssemblyAnnotationWriter.h"
20 #include "llvm/IR/DebugInfo.h"
21 #include "llvm/IR/DiagnosticInfo.h"
22 #include "llvm/IR/DiagnosticPrinter.h"
23 #include "llvm/IR/IntrinsicInst.h"
24 #include "llvm/IR/LLVMContext.h"
25 #include "llvm/IR/Module.h"
26 #include "llvm/IR/ModuleSummaryIndex.h"
27 #include "llvm/IR/Type.h"
28 #include "llvm/Support/CommandLine.h"
29 #include "llvm/Support/Error.h"
30 #include "llvm/Support/FileSystem.h"
31 #include "llvm/Support/FormattedStream.h"
32 #include "llvm/Support/InitLLVM.h"
33 #include "llvm/Support/MemoryBuffer.h"
34 #include "llvm/Support/ToolOutputFile.h"
35 #include "llvm/Support/WithColor.h"
36 #include <system_error>
37 using namespace llvm;
38 
39 static cl::OptionCategory DisCategory("Disassembler Options");
40 
41 static cl::list<std::string> InputFilenames(cl::Positional,
42                                             cl::desc("[input bitcode]..."),
43                                             cl::cat(DisCategory));
44 
45 static cl::opt<std::string> OutputFilename("o",
46                                            cl::desc("Override output filename"),
47                                            cl::value_desc("filename"),
48                                            cl::cat(DisCategory));
49 
50 static cl::opt<bool> Force("f", cl::desc("Enable binary output on terminals"),
51                            cl::cat(DisCategory));
52 
53 static cl::opt<bool> DontPrint("disable-output",
54                                cl::desc("Don't output the .ll file"),
55                                cl::Hidden, cl::cat(DisCategory));
56 
57 static cl::opt<bool>
58     SetImporting("set-importing",
59                  cl::desc("Set lazy loading to pretend to import a module"),
60                  cl::Hidden, cl::cat(DisCategory));
61 
62 static cl::opt<bool>
63     ShowAnnotations("show-annotations",
64                     cl::desc("Add informational comments to the .ll file"),
65                     cl::cat(DisCategory));
66 
67 static cl::opt<bool> PreserveAssemblyUseListOrder(
68     "preserve-ll-uselistorder",
69     cl::desc("Preserve use-list order when writing LLVM assembly."),
70     cl::init(false), cl::Hidden, cl::cat(DisCategory));
71 
72 static cl::opt<bool>
73     MaterializeMetadata("materialize-metadata",
74                         cl::desc("Load module without materializing metadata, "
75                                  "then materialize only the metadata"),
76                         cl::cat(DisCategory));
77 
78 static cl::opt<bool> PrintThinLTOIndexOnly(
79     "print-thinlto-index-only",
80     cl::desc("Only read thinlto index and print the index as LLVM assembly."),
81     cl::init(false), cl::Hidden, cl::cat(DisCategory));
82 
83 namespace {
84 
85 static void printDebugLoc(const DebugLoc &DL, formatted_raw_ostream &OS) {
86   OS << DL.getLine() << ":" << DL.getCol();
87   if (DILocation *IDL = DL.getInlinedAt()) {
88     OS << "@";
89     printDebugLoc(IDL, OS);
90   }
91 }
92 class CommentWriter : public AssemblyAnnotationWriter {
93 public:
94   void emitFunctionAnnot(const Function *F,
95                          formatted_raw_ostream &OS) override {
96     OS << "; [#uses=" << F->getNumUses() << ']';  // Output # uses
97     OS << '\n';
98   }
99   void printInfoComment(const Value &V, formatted_raw_ostream &OS) override {
100     bool Padded = false;
101     if (!V.getType()->isVoidTy()) {
102       OS.PadToColumn(50);
103       Padded = true;
104       // Output # uses and type
105       OS << "; [#uses=" << V.getNumUses() << " type=" << *V.getType() << "]";
106     }
107     if (const Instruction *I = dyn_cast<Instruction>(&V)) {
108       if (const DebugLoc &DL = I->getDebugLoc()) {
109         if (!Padded) {
110           OS.PadToColumn(50);
111           Padded = true;
112           OS << ";";
113         }
114         OS << " [debug line = ";
115         printDebugLoc(DL,OS);
116         OS << "]";
117       }
118       if (const DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I)) {
119         if (!Padded) {
120           OS.PadToColumn(50);
121           OS << ";";
122         }
123         OS << " [debug variable = " << DDI->getVariable()->getName() << "]";
124       }
125       else if (const DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) {
126         if (!Padded) {
127           OS.PadToColumn(50);
128           OS << ";";
129         }
130         OS << " [debug variable = " << DVI->getVariable()->getName() << "]";
131       }
132     }
133   }
134 };
135 
136 struct LLVMDisDiagnosticHandler : public DiagnosticHandler {
137   char *Prefix;
138   LLVMDisDiagnosticHandler(char *PrefixPtr) : Prefix(PrefixPtr) {}
139   bool handleDiagnostics(const DiagnosticInfo &DI) override {
140     raw_ostream &OS = errs();
141     OS << Prefix << ": ";
142     switch (DI.getSeverity()) {
143       case DS_Error: WithColor::error(OS); break;
144       case DS_Warning: WithColor::warning(OS); break;
145       case DS_Remark: OS << "remark: "; break;
146       case DS_Note: WithColor::note(OS); break;
147     }
148 
149     DiagnosticPrinterRawOStream DP(OS);
150     DI.print(DP);
151     OS << '\n';
152 
153     if (DI.getSeverity() == DS_Error)
154       exit(1);
155     return true;
156   }
157 };
158 } // end anon namespace
159 
160 static ExitOnError ExitOnErr;
161 
162 int main(int argc, char **argv) {
163   InitLLVM X(argc, argv);
164 
165   ExitOnErr.setBanner(std::string(argv[0]) + ": error: ");
166 
167   cl::HideUnrelatedOptions({&DisCategory, &getColorCategory()});
168   cl::ParseCommandLineOptions(argc, argv, "llvm .bc -> .ll disassembler\n");
169 
170   LLVMContext Context;
171   Context.setDiagnosticHandler(
172       std::make_unique<LLVMDisDiagnosticHandler>(argv[0]));
173 
174   if (InputFilenames.size() < 1) {
175     InputFilenames.push_back("-");
176   } else if (InputFilenames.size() > 1 && !OutputFilename.empty()) {
177     errs()
178         << "error: output file name cannot be set for multiple input files\n";
179     return 1;
180   }
181 
182   for (std::string InputFilename : InputFilenames) {
183     ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
184         MemoryBuffer::getFileOrSTDIN(InputFilename);
185     if (std::error_code EC = BufferOrErr.getError()) {
186       WithColor::error() << InputFilename << ": " << EC.message() << '\n';
187       return 1;
188     }
189     std::unique_ptr<MemoryBuffer> MB = std::move(BufferOrErr.get());
190 
191     BitcodeFileContents IF = ExitOnErr(llvm::getBitcodeFileContents(*MB));
192 
193     const size_t N = IF.Mods.size();
194 
195     if (OutputFilename == "-" && N > 1)
196       errs() << "only single module bitcode files can be written to stdout\n";
197 
198     for (size_t I = 0; I < N; ++I) {
199       BitcodeModule MB = IF.Mods[I];
200 
201       std::unique_ptr<Module> M;
202 
203       if (!PrintThinLTOIndexOnly) {
204         M = ExitOnErr(
205             MB.getLazyModule(Context, MaterializeMetadata, SetImporting));
206         if (MaterializeMetadata)
207           ExitOnErr(M->materializeMetadata());
208         else
209           ExitOnErr(M->materializeAll());
210       }
211 
212       BitcodeLTOInfo LTOInfo = ExitOnErr(MB.getLTOInfo());
213       std::unique_ptr<ModuleSummaryIndex> Index;
214       if (LTOInfo.HasSummary)
215         Index = ExitOnErr(MB.getSummary());
216 
217       std::string FinalFilename(OutputFilename);
218 
219       // Just use stdout.  We won't actually print anything on it.
220       if (DontPrint)
221         FinalFilename = "-";
222 
223       if (FinalFilename.empty()) { // Unspecified output, infer it.
224         if (InputFilename == "-") {
225           FinalFilename = "-";
226         } else {
227           StringRef IFN = InputFilename;
228           FinalFilename = (IFN.endswith(".bc") ? IFN.drop_back(3) : IFN).str();
229           if (N > 1)
230             FinalFilename += std::string(".") + std::to_string(I);
231           FinalFilename += ".ll";
232         }
233       } else {
234         if (N > 1)
235           FinalFilename += std::string(".") + std::to_string(I);
236       }
237 
238       std::error_code EC;
239       std::unique_ptr<ToolOutputFile> Out(
240           new ToolOutputFile(FinalFilename, EC, sys::fs::OF_TextWithCRLF));
241       if (EC) {
242         errs() << EC.message() << '\n';
243         return 1;
244       }
245 
246       std::unique_ptr<AssemblyAnnotationWriter> Annotator;
247       if (ShowAnnotations)
248         Annotator.reset(new CommentWriter());
249 
250       // All that llvm-dis does is write the assembly to a file.
251       if (!DontPrint) {
252         if (M)
253           M->print(Out->os(), Annotator.get(), PreserveAssemblyUseListOrder);
254         if (Index)
255           Index->print(Out->os());
256       }
257 
258       // Declare success.
259       Out->keep();
260     }
261   }
262 
263   return 0;
264 }
265