1 //===-- llvm-dis.cpp - The low-level LLVM disassembler --------------------===//
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 utility may be invoked in the following manner:
11 //  llvm-dis [options]      - Read LLVM bitcode from stdin, write asm to stdout
12 //  llvm-dis [options] x.bc - Read LLVM bitcode from the x.bc file, write asm
13 //                            to the x.ll file.
14 //  Options:
15 //      --help   - Output information about command line switches
16 //
17 //===----------------------------------------------------------------------===//
18 
19 #include "llvm/IR/LLVMContext.h"
20 #include "llvm/Bitcode/BitcodeReader.h"
21 #include "llvm/IR/AssemblyAnnotationWriter.h"
22 #include "llvm/IR/DebugInfo.h"
23 #include "llvm/IR/DiagnosticInfo.h"
24 #include "llvm/IR/DiagnosticPrinter.h"
25 #include "llvm/IR/IntrinsicInst.h"
26 #include "llvm/IR/Module.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/ManagedStatic.h"
33 #include "llvm/Support/MemoryBuffer.h"
34 #include "llvm/Support/PrettyStackTrace.h"
35 #include "llvm/Support/Signals.h"
36 #include "llvm/Support/ToolOutputFile.h"
37 #include <system_error>
38 using namespace llvm;
39 
40 static cl::opt<std::string>
41 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
42 
43 static cl::opt<std::string>
44 OutputFilename("o", cl::desc("Override output filename"),
45                cl::value_desc("filename"));
46 
47 static cl::opt<bool>
48 Force("f", cl::desc("Enable binary output on terminals"));
49 
50 static cl::opt<bool>
51 DontPrint("disable-output", cl::desc("Don't output the .ll file"), cl::Hidden);
52 
53 static cl::opt<bool>
54 ShowAnnotations("show-annotations",
55                 cl::desc("Add informational comments to the .ll file"));
56 
57 static cl::opt<bool> PreserveAssemblyUseListOrder(
58     "preserve-ll-uselistorder",
59     cl::desc("Preserve use-list order when writing LLVM assembly."),
60     cl::init(false), cl::Hidden);
61 
62 static cl::opt<bool>
63     MaterializeMetadata("materialize-metadata",
64                         cl::desc("Load module without materializing metadata, "
65                                  "then materialize only the metadata"));
66 
67 namespace {
68 
69 static void printDebugLoc(const DebugLoc &DL, formatted_raw_ostream &OS) {
70   OS << DL.getLine() << ":" << DL.getCol();
71   if (DILocation *IDL = DL.getInlinedAt()) {
72     OS << "@";
73     printDebugLoc(IDL, OS);
74   }
75 }
76 class CommentWriter : public AssemblyAnnotationWriter {
77 public:
78   void emitFunctionAnnot(const Function *F,
79                          formatted_raw_ostream &OS) override {
80     OS << "; [#uses=" << F->getNumUses() << ']';  // Output # uses
81     OS << '\n';
82   }
83   void printInfoComment(const Value &V, formatted_raw_ostream &OS) override {
84     bool Padded = false;
85     if (!V.getType()->isVoidTy()) {
86       OS.PadToColumn(50);
87       Padded = true;
88       // Output # uses and type
89       OS << "; [#uses=" << V.getNumUses() << " type=" << *V.getType() << "]";
90     }
91     if (const Instruction *I = dyn_cast<Instruction>(&V)) {
92       if (const DebugLoc &DL = I->getDebugLoc()) {
93         if (!Padded) {
94           OS.PadToColumn(50);
95           Padded = true;
96           OS << ";";
97         }
98         OS << " [debug line = ";
99         printDebugLoc(DL,OS);
100         OS << "]";
101       }
102       if (const DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I)) {
103         if (!Padded) {
104           OS.PadToColumn(50);
105           OS << ";";
106         }
107         OS << " [debug variable = " << DDI->getVariable()->getName() << "]";
108       }
109       else if (const DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) {
110         if (!Padded) {
111           OS.PadToColumn(50);
112           OS << ";";
113         }
114         OS << " [debug variable = " << DVI->getVariable()->getName() << "]";
115       }
116     }
117   }
118 };
119 
120 } // end anon namespace
121 
122 static void diagnosticHandler(const DiagnosticInfo &DI, void *Context) {
123   raw_ostream &OS = errs();
124   OS << (char *)Context << ": ";
125   switch (DI.getSeverity()) {
126   case DS_Error: OS << "error: "; break;
127   case DS_Warning: OS << "warning: "; break;
128   case DS_Remark: OS << "remark: "; break;
129   case DS_Note: OS << "note: "; break;
130   }
131 
132   DiagnosticPrinterRawOStream DP(OS);
133   DI.print(DP);
134   OS << '\n';
135 
136   if (DI.getSeverity() == DS_Error)
137     exit(1);
138 }
139 
140 static ExitOnError ExitOnErr;
141 
142 static std::unique_ptr<Module> openInputFile(LLVMContext &Context) {
143   std::unique_ptr<MemoryBuffer> MB =
144       ExitOnErr(errorOrToExpected(MemoryBuffer::getFileOrSTDIN(InputFilename)));
145   std::unique_ptr<Module> M =
146       ExitOnErr(getOwningLazyBitcodeModule(std::move(MB), Context,
147                                            /*ShouldLazyLoadMetadata=*/true));
148   if (MaterializeMetadata)
149     ExitOnErr(M->materializeMetadata());
150   else
151     ExitOnErr(M->materializeAll());
152   return M;
153 }
154 
155 int main(int argc, char **argv) {
156   // Print a stack trace if we signal out.
157   sys::PrintStackTraceOnErrorSignal(argv[0]);
158   PrettyStackTraceProgram X(argc, argv);
159 
160   ExitOnErr.setBanner(std::string(argv[0]) + ": error: ");
161 
162   LLVMContext Context;
163   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
164 
165   Context.setDiagnosticHandler(diagnosticHandler, argv[0]);
166 
167   cl::ParseCommandLineOptions(argc, argv, "llvm .bc -> .ll disassembler\n");
168 
169   std::unique_ptr<Module> M = openInputFile(Context);
170 
171   // Just use stdout.  We won't actually print anything on it.
172   if (DontPrint)
173     OutputFilename = "-";
174 
175   if (OutputFilename.empty()) { // Unspecified output, infer it.
176     if (InputFilename == "-") {
177       OutputFilename = "-";
178     } else {
179       StringRef IFN = InputFilename;
180       OutputFilename = (IFN.endswith(".bc") ? IFN.drop_back(3) : IFN).str();
181       OutputFilename += ".ll";
182     }
183   }
184 
185   std::error_code EC;
186   std::unique_ptr<tool_output_file> Out(
187       new tool_output_file(OutputFilename, EC, sys::fs::F_None));
188   if (EC) {
189     errs() << EC.message() << '\n';
190     return 1;
191   }
192 
193   std::unique_ptr<AssemblyAnnotationWriter> Annotator;
194   if (ShowAnnotations)
195     Annotator.reset(new CommentWriter());
196 
197   // All that llvm-dis does is write the assembly to a file.
198   if (!DontPrint)
199     M->print(Out->os(), Annotator.get(), PreserveAssemblyUseListOrder);
200 
201   // Declare success.
202   Out->keep();
203 
204   return 0;
205 }
206