1 //===-- llvm-lto: a simple command-line program to link modules with LTO --===//
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 program takes in a list of bitcode files, links them, performs link-time
11 // optimization, and outputs an object file.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "llvm/ADT/StringSet.h"
16 #include "llvm/CodeGen/CommandFlags.h"
17 #include "llvm/LTO/LTOCodeGenerator.h"
18 #include "llvm/LTO/LTOModule.h"
19 #include "llvm/Support/CommandLine.h"
20 #include "llvm/Support/FileSystem.h"
21 #include "llvm/Support/ManagedStatic.h"
22 #include "llvm/Support/PrettyStackTrace.h"
23 #include "llvm/Support/Signals.h"
24 #include "llvm/Support/TargetSelect.h"
25 #include "llvm/Support/raw_ostream.h"
26
27 using namespace llvm;
28
29 static cl::opt<bool>
30 DisableOpt("disable-opt", cl::init(false),
31 cl::desc("Do not run any optimization passes"));
32
33 static cl::opt<bool>
34 DisableInline("disable-inlining", cl::init(false),
35 cl::desc("Do not run the inliner pass"));
36
37 static cl::opt<bool>
38 DisableGVNLoadPRE("disable-gvn-loadpre", cl::init(false),
39 cl::desc("Do not run the GVN load PRE pass"));
40
41 static cl::opt<bool>
42 DisableLTOVectorization("disable-lto-vectorization", cl::init(false),
43 cl::desc("Do not run loop or slp vectorization during LTO"));
44
45 static cl::opt<bool>
46 UseDiagnosticHandler("use-diagnostic-handler", cl::init(false),
47 cl::desc("Use a diagnostic handler to test the handler interface"));
48
49 static cl::list<std::string>
50 InputFilenames(cl::Positional, cl::OneOrMore,
51 cl::desc("<input bitcode files>"));
52
53 static cl::opt<std::string>
54 OutputFilename("o", cl::init(""),
55 cl::desc("Override output filename"),
56 cl::value_desc("filename"));
57
58 static cl::list<std::string>
59 ExportedSymbols("exported-symbol",
60 cl::desc("Symbol to export from the resulting object file"),
61 cl::ZeroOrMore);
62
63 static cl::list<std::string>
64 DSOSymbols("dso-symbol",
65 cl::desc("Symbol to put in the symtab in the resulting dso"),
66 cl::ZeroOrMore);
67
68 static cl::opt<bool> ListSymbolsOnly(
69 "list-symbols-only", cl::init(false),
70 cl::desc("Instead of running LTO, list the symbols in each IR file"));
71
72 namespace {
73 struct ModuleInfo {
74 std::vector<bool> CanBeHidden;
75 };
76 }
77
handleDiagnostics(lto_codegen_diagnostic_severity_t Severity,const char * Msg,void *)78 void handleDiagnostics(lto_codegen_diagnostic_severity_t Severity,
79 const char *Msg, void *) {
80 switch (Severity) {
81 case LTO_DS_NOTE:
82 errs() << "note: ";
83 break;
84 case LTO_DS_REMARK:
85 errs() << "remark: ";
86 break;
87 case LTO_DS_ERROR:
88 errs() << "error: ";
89 break;
90 case LTO_DS_WARNING:
91 errs() << "warning: ";
92 break;
93 }
94 errs() << Msg << "\n";
95 }
96
97 std::unique_ptr<LTOModule>
getLocalLTOModule(StringRef Path,std::unique_ptr<MemoryBuffer> & Buffer,const TargetOptions & Options,std::string & Error)98 getLocalLTOModule(StringRef Path, std::unique_ptr<MemoryBuffer> &Buffer,
99 const TargetOptions &Options, std::string &Error) {
100 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
101 MemoryBuffer::getFile(Path);
102 if (std::error_code EC = BufferOrErr.getError()) {
103 Error = EC.message();
104 return nullptr;
105 }
106 Buffer = std::move(BufferOrErr.get());
107 return std::unique_ptr<LTOModule>(LTOModule::createInLocalContext(
108 Buffer->getBufferStart(), Buffer->getBufferSize(), Options, Error, Path));
109 }
110
111 /// \brief List symbols in each IR file.
112 ///
113 /// The main point here is to provide lit-testable coverage for the LTOModule
114 /// functionality that's exposed by the C API to list symbols. Moreover, this
115 /// provides testing coverage for modules that have been created in their own
116 /// contexts.
listSymbols(StringRef Command,const TargetOptions & Options)117 int listSymbols(StringRef Command, const TargetOptions &Options) {
118 for (auto &Filename : InputFilenames) {
119 std::string Error;
120 std::unique_ptr<MemoryBuffer> Buffer;
121 std::unique_ptr<LTOModule> Module =
122 getLocalLTOModule(Filename, Buffer, Options, Error);
123 if (!Module) {
124 errs() << Command << ": error loading file '" << Filename
125 << "': " << Error << "\n";
126 return 1;
127 }
128
129 // List the symbols.
130 outs() << Filename << ":\n";
131 for (int I = 0, E = Module->getSymbolCount(); I != E; ++I)
132 outs() << Module->getSymbolName(I) << "\n";
133 }
134 return 0;
135 }
136
main(int argc,char ** argv)137 int main(int argc, char **argv) {
138 // Print a stack trace if we signal out.
139 sys::PrintStackTraceOnErrorSignal();
140 PrettyStackTraceProgram X(argc, argv);
141
142 llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
143 cl::ParseCommandLineOptions(argc, argv, "llvm LTO linker\n");
144
145 // Initialize the configured targets.
146 InitializeAllTargets();
147 InitializeAllTargetMCs();
148 InitializeAllAsmPrinters();
149 InitializeAllAsmParsers();
150
151 // set up the TargetOptions for the machine
152 TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
153
154 if (ListSymbolsOnly)
155 return listSymbols(argv[0], Options);
156
157 unsigned BaseArg = 0;
158
159 LTOCodeGenerator CodeGen;
160
161 if (UseDiagnosticHandler)
162 CodeGen.setDiagnosticHandler(handleDiagnostics, nullptr);
163
164 switch (RelocModel) {
165 case Reloc::Static:
166 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_STATIC);
167 break;
168 case Reloc::PIC_:
169 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC);
170 break;
171 case Reloc::DynamicNoPIC:
172 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC);
173 break;
174 default:
175 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DEFAULT);
176 }
177
178 CodeGen.setDebugInfo(LTO_DEBUG_MODEL_DWARF);
179 CodeGen.setTargetOptions(Options);
180
181 llvm::StringSet<llvm::MallocAllocator> DSOSymbolsSet;
182 for (unsigned i = 0; i < DSOSymbols.size(); ++i)
183 DSOSymbolsSet.insert(DSOSymbols[i]);
184
185 std::vector<std::string> KeptDSOSyms;
186
187 for (unsigned i = BaseArg; i < InputFilenames.size(); ++i) {
188 std::string error;
189 std::unique_ptr<LTOModule> Module(
190 LTOModule::createFromFile(InputFilenames[i].c_str(), Options, error));
191 if (!error.empty()) {
192 errs() << argv[0] << ": error loading file '" << InputFilenames[i]
193 << "': " << error << "\n";
194 return 1;
195 }
196
197 if (!CodeGen.addModule(Module.get()))
198 return 1;
199
200 unsigned NumSyms = Module->getSymbolCount();
201 for (unsigned I = 0; I < NumSyms; ++I) {
202 StringRef Name = Module->getSymbolName(I);
203 if (!DSOSymbolsSet.count(Name))
204 continue;
205 lto_symbol_attributes Attrs = Module->getSymbolAttributes(I);
206 unsigned Scope = Attrs & LTO_SYMBOL_SCOPE_MASK;
207 if (Scope != LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN)
208 KeptDSOSyms.push_back(Name);
209 }
210 }
211
212 // Add all the exported symbols to the table of symbols to preserve.
213 for (unsigned i = 0; i < ExportedSymbols.size(); ++i)
214 CodeGen.addMustPreserveSymbol(ExportedSymbols[i].c_str());
215
216 // Add all the dso symbols to the table of symbols to expose.
217 for (unsigned i = 0; i < KeptDSOSyms.size(); ++i)
218 CodeGen.addMustPreserveSymbol(KeptDSOSyms[i].c_str());
219
220 std::string attrs;
221 for (unsigned i = 0; i < MAttrs.size(); ++i) {
222 if (i > 0)
223 attrs.append(",");
224 attrs.append(MAttrs[i]);
225 }
226
227 if (!attrs.empty())
228 CodeGen.setAttr(attrs.c_str());
229
230 if (!OutputFilename.empty()) {
231 size_t len = 0;
232 std::string ErrorInfo;
233 const void *Code =
234 CodeGen.compile(&len, DisableOpt, DisableInline, DisableGVNLoadPRE,
235 DisableLTOVectorization, ErrorInfo);
236 if (!Code) {
237 errs() << argv[0]
238 << ": error compiling the code: " << ErrorInfo << "\n";
239 return 1;
240 }
241
242 std::error_code EC;
243 raw_fd_ostream FileStream(OutputFilename, EC, sys::fs::F_None);
244 if (EC) {
245 errs() << argv[0] << ": error opening the file '" << OutputFilename
246 << "': " << EC.message() << "\n";
247 return 1;
248 }
249
250 FileStream.write(reinterpret_cast<const char *>(Code), len);
251 } else {
252 std::string ErrorInfo;
253 const char *OutputName = nullptr;
254 if (!CodeGen.compile_to_file(&OutputName, DisableOpt, DisableInline,
255 DisableGVNLoadPRE, DisableLTOVectorization,
256 ErrorInfo)) {
257 errs() << argv[0]
258 << ": error compiling the code: " << ErrorInfo
259 << "\n";
260 return 1;
261 }
262
263 outs() << "Wrote native object file '" << OutputName << "'\n";
264 }
265
266 return 0;
267 }
268