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/ReaderWriter.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/DataStream.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 namespace {
63 
printDebugLoc(const DebugLoc & DL,formatted_raw_ostream & OS)64 static void printDebugLoc(const DebugLoc &DL, formatted_raw_ostream &OS) {
65   OS << DL.getLine() << ":" << DL.getCol();
66   if (MDLocation *IDL = DL.getInlinedAt()) {
67     OS << "@";
68     printDebugLoc(IDL, OS);
69   }
70 }
71 class CommentWriter : public AssemblyAnnotationWriter {
72 public:
emitFunctionAnnot(const Function * F,formatted_raw_ostream & OS)73   void emitFunctionAnnot(const Function *F,
74                          formatted_raw_ostream &OS) override {
75     OS << "; [#uses=" << F->getNumUses() << ']';  // Output # uses
76     OS << '\n';
77   }
printInfoComment(const Value & V,formatted_raw_ostream & OS)78   void printInfoComment(const Value &V, formatted_raw_ostream &OS) override {
79     bool Padded = false;
80     if (!V.getType()->isVoidTy()) {
81       OS.PadToColumn(50);
82       Padded = true;
83       OS << "; [#uses=" << V.getNumUses() << " type=" << *V.getType() << "]";  // Output # uses and type
84     }
85     if (const Instruction *I = dyn_cast<Instruction>(&V)) {
86       if (const DebugLoc &DL = I->getDebugLoc()) {
87         if (!Padded) {
88           OS.PadToColumn(50);
89           Padded = true;
90           OS << ";";
91         }
92         OS << " [debug line = ";
93         printDebugLoc(DL,OS);
94         OS << "]";
95       }
96       if (const DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I)) {
97         DIVariable Var(DDI->getVariable());
98         if (!Padded) {
99           OS.PadToColumn(50);
100           OS << ";";
101         }
102         OS << " [debug variable = " << Var->getName() << "]";
103       }
104       else if (const DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) {
105         DIVariable Var(DVI->getVariable());
106         if (!Padded) {
107           OS.PadToColumn(50);
108           OS << ";";
109         }
110         OS << " [debug variable = " << Var->getName() << "]";
111       }
112     }
113   }
114 };
115 
116 } // end anon namespace
117 
diagnosticHandler(const DiagnosticInfo & DI,void * Context)118 static void diagnosticHandler(const DiagnosticInfo &DI, void *Context) {
119   raw_ostream &OS = errs();
120   OS << (char *)Context << ": ";
121   switch (DI.getSeverity()) {
122   case DS_Error: OS << "error: "; break;
123   case DS_Warning: OS << "warning: "; break;
124   case DS_Remark: OS << "remark: "; break;
125   case DS_Note: OS << "note: "; break;
126   }
127 
128   DiagnosticPrinterRawOStream DP(OS);
129   DI.print(DP);
130   OS << '\n';
131 
132   if (DI.getSeverity() == DS_Error)
133     exit(1);
134 }
135 
main(int argc,char ** argv)136 int main(int argc, char **argv) {
137   // Print a stack trace if we signal out.
138   sys::PrintStackTraceOnErrorSignal();
139   PrettyStackTraceProgram X(argc, argv);
140 
141   LLVMContext &Context = getGlobalContext();
142   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
143 
144   Context.setDiagnosticHandler(diagnosticHandler, argv[0]);
145 
146   cl::ParseCommandLineOptions(argc, argv, "llvm .bc -> .ll disassembler\n");
147 
148   std::string ErrorMessage;
149   std::unique_ptr<Module> M;
150 
151   // Use the bitcode streaming interface
152   DataStreamer *Streamer = getDataFileStreamer(InputFilename, &ErrorMessage);
153   if (Streamer) {
154     std::string DisplayFilename;
155     if (InputFilename == "-")
156       DisplayFilename = "<stdin>";
157     else
158       DisplayFilename = InputFilename;
159     ErrorOr<std::unique_ptr<Module>> MOrErr =
160         getStreamedBitcodeModule(DisplayFilename, Streamer, Context);
161     M = std::move(*MOrErr);
162     M->materializeAllPermanently();
163   }
164 
165   // Just use stdout.  We won't actually print anything on it.
166   if (DontPrint)
167     OutputFilename = "-";
168 
169   if (OutputFilename.empty()) { // Unspecified output, infer it.
170     if (InputFilename == "-") {
171       OutputFilename = "-";
172     } else {
173       const std::string &IFN = InputFilename;
174       int Len = IFN.length();
175       // If the source ends in .bc, strip it off.
176       if (IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c')
177         OutputFilename = std::string(IFN.begin(), IFN.end()-3)+".ll";
178       else
179         OutputFilename = IFN+".ll";
180     }
181   }
182 
183   std::error_code EC;
184   std::unique_ptr<tool_output_file> Out(
185       new tool_output_file(OutputFilename, EC, sys::fs::F_None));
186   if (EC) {
187     errs() << EC.message() << '\n';
188     return 1;
189   }
190 
191   std::unique_ptr<AssemblyAnnotationWriter> Annotator;
192   if (ShowAnnotations)
193     Annotator.reset(new CommentWriter());
194 
195   // All that llvm-dis does is write the assembly to a file.
196   if (!DontPrint)
197     M->print(Out->os(), Annotator.get(), PreserveAssemblyUseListOrder);
198 
199   // Declare success.
200   Out->keep();
201 
202   return 0;
203 }
204