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<char>
30 OptLevel("O",
31 cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
32 "(default = '-O2')"),
33 cl::Prefix,
34 cl::ZeroOrMore,
35 cl::init('2'));
36
37 static cl::opt<bool>
38 DisableInline("disable-inlining", cl::init(false),
39 cl::desc("Do not run the inliner pass"));
40
41 static cl::opt<bool>
42 DisableGVNLoadPRE("disable-gvn-loadpre", cl::init(false),
43 cl::desc("Do not run the GVN load PRE pass"));
44
45 static cl::opt<bool>
46 DisableLTOVectorization("disable-lto-vectorization", cl::init(false),
47 cl::desc("Do not run loop or slp vectorization during LTO"));
48
49 static cl::opt<bool>
50 UseDiagnosticHandler("use-diagnostic-handler", cl::init(false),
51 cl::desc("Use a diagnostic handler to test the handler interface"));
52
53 static cl::list<std::string>
54 InputFilenames(cl::Positional, cl::OneOrMore,
55 cl::desc("<input bitcode files>"));
56
57 static cl::opt<std::string>
58 OutputFilename("o", cl::init(""),
59 cl::desc("Override output filename"),
60 cl::value_desc("filename"));
61
62 static cl::list<std::string>
63 ExportedSymbols("exported-symbol",
64 cl::desc("Symbol to export from the resulting object file"),
65 cl::ZeroOrMore);
66
67 static cl::list<std::string>
68 DSOSymbols("dso-symbol",
69 cl::desc("Symbol to put in the symtab in the resulting dso"),
70 cl::ZeroOrMore);
71
72 static cl::opt<bool> ListSymbolsOnly(
73 "list-symbols-only", cl::init(false),
74 cl::desc("Instead of running LTO, list the symbols in each IR file"));
75
76 static cl::opt<bool> SetMergedModule(
77 "set-merged-module", cl::init(false),
78 cl::desc("Use the first input module as the merged module"));
79
80 namespace {
81 struct ModuleInfo {
82 std::vector<bool> CanBeHidden;
83 };
84 }
85
handleDiagnostics(lto_codegen_diagnostic_severity_t Severity,const char * Msg,void *)86 static void handleDiagnostics(lto_codegen_diagnostic_severity_t Severity,
87 const char *Msg, void *) {
88 switch (Severity) {
89 case LTO_DS_NOTE:
90 errs() << "note: ";
91 break;
92 case LTO_DS_REMARK:
93 errs() << "remark: ";
94 break;
95 case LTO_DS_ERROR:
96 errs() << "error: ";
97 break;
98 case LTO_DS_WARNING:
99 errs() << "warning: ";
100 break;
101 }
102 errs() << Msg << "\n";
103 }
104
105 static std::unique_ptr<LTOModule>
getLocalLTOModule(StringRef Path,std::unique_ptr<MemoryBuffer> & Buffer,const TargetOptions & Options,std::string & Error)106 getLocalLTOModule(StringRef Path, std::unique_ptr<MemoryBuffer> &Buffer,
107 const TargetOptions &Options, std::string &Error) {
108 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
109 MemoryBuffer::getFile(Path);
110 if (std::error_code EC = BufferOrErr.getError()) {
111 Error = EC.message();
112 return nullptr;
113 }
114 Buffer = std::move(BufferOrErr.get());
115 return std::unique_ptr<LTOModule>(LTOModule::createInLocalContext(
116 Buffer->getBufferStart(), Buffer->getBufferSize(), Options, Error, Path));
117 }
118
119 /// \brief List symbols in each IR file.
120 ///
121 /// The main point here is to provide lit-testable coverage for the LTOModule
122 /// functionality that's exposed by the C API to list symbols. Moreover, this
123 /// provides testing coverage for modules that have been created in their own
124 /// contexts.
listSymbols(StringRef Command,const TargetOptions & Options)125 static int listSymbols(StringRef Command, const TargetOptions &Options) {
126 for (auto &Filename : InputFilenames) {
127 std::string Error;
128 std::unique_ptr<MemoryBuffer> Buffer;
129 std::unique_ptr<LTOModule> Module =
130 getLocalLTOModule(Filename, Buffer, Options, Error);
131 if (!Module) {
132 errs() << Command << ": error loading file '" << Filename
133 << "': " << Error << "\n";
134 return 1;
135 }
136
137 // List the symbols.
138 outs() << Filename << ":\n";
139 for (int I = 0, E = Module->getSymbolCount(); I != E; ++I)
140 outs() << Module->getSymbolName(I) << "\n";
141 }
142 return 0;
143 }
144
main(int argc,char ** argv)145 int main(int argc, char **argv) {
146 // Print a stack trace if we signal out.
147 sys::PrintStackTraceOnErrorSignal();
148 PrettyStackTraceProgram X(argc, argv);
149
150 llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
151 cl::ParseCommandLineOptions(argc, argv, "llvm LTO linker\n");
152
153 if (OptLevel < '0' || OptLevel > '3') {
154 errs() << argv[0] << ": optimization level must be between 0 and 3\n";
155 return 1;
156 }
157
158 // Initialize the configured targets.
159 InitializeAllTargets();
160 InitializeAllTargetMCs();
161 InitializeAllAsmPrinters();
162 InitializeAllAsmParsers();
163
164 // set up the TargetOptions for the machine
165 TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
166
167 if (ListSymbolsOnly)
168 return listSymbols(argv[0], Options);
169
170 unsigned BaseArg = 0;
171
172 LTOCodeGenerator CodeGen;
173
174 if (UseDiagnosticHandler)
175 CodeGen.setDiagnosticHandler(handleDiagnostics, nullptr);
176
177 switch (RelocModel) {
178 case Reloc::Static:
179 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_STATIC);
180 break;
181 case Reloc::PIC_:
182 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC);
183 break;
184 case Reloc::DynamicNoPIC:
185 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC);
186 break;
187 default:
188 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DEFAULT);
189 }
190
191 CodeGen.setDebugInfo(LTO_DEBUG_MODEL_DWARF);
192 CodeGen.setTargetOptions(Options);
193
194 llvm::StringSet<llvm::MallocAllocator> DSOSymbolsSet;
195 for (unsigned i = 0; i < DSOSymbols.size(); ++i)
196 DSOSymbolsSet.insert(DSOSymbols[i]);
197
198 std::vector<std::string> KeptDSOSyms;
199
200 for (unsigned i = BaseArg; i < InputFilenames.size(); ++i) {
201 std::string error;
202 std::unique_ptr<LTOModule> Module(
203 LTOModule::createFromFile(InputFilenames[i].c_str(), Options, error));
204 if (!error.empty()) {
205 errs() << argv[0] << ": error loading file '" << InputFilenames[i]
206 << "': " << error << "\n";
207 return 1;
208 }
209
210 LTOModule *LTOMod = Module.get();
211
212 // We use the first input module as the destination module when
213 // SetMergedModule is true.
214 if (SetMergedModule && i == BaseArg) {
215 // Transfer ownership to the code generator.
216 CodeGen.setModule(Module.release());
217 } else if (!CodeGen.addModule(Module.get()))
218 return 1;
219
220 unsigned NumSyms = LTOMod->getSymbolCount();
221 for (unsigned I = 0; I < NumSyms; ++I) {
222 StringRef Name = LTOMod->getSymbolName(I);
223 if (!DSOSymbolsSet.count(Name))
224 continue;
225 lto_symbol_attributes Attrs = LTOMod->getSymbolAttributes(I);
226 unsigned Scope = Attrs & LTO_SYMBOL_SCOPE_MASK;
227 if (Scope != LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN)
228 KeptDSOSyms.push_back(Name);
229 }
230 }
231
232 // Add all the exported symbols to the table of symbols to preserve.
233 for (unsigned i = 0; i < ExportedSymbols.size(); ++i)
234 CodeGen.addMustPreserveSymbol(ExportedSymbols[i].c_str());
235
236 // Add all the dso symbols to the table of symbols to expose.
237 for (unsigned i = 0; i < KeptDSOSyms.size(); ++i)
238 CodeGen.addMustPreserveSymbol(KeptDSOSyms[i].c_str());
239
240 // Set cpu and attrs strings for the default target/subtarget.
241 CodeGen.setCpu(MCPU.c_str());
242
243 CodeGen.setOptLevel(OptLevel - '0');
244
245 std::string attrs;
246 for (unsigned i = 0; i < MAttrs.size(); ++i) {
247 if (i > 0)
248 attrs.append(",");
249 attrs.append(MAttrs[i]);
250 }
251
252 if (!attrs.empty())
253 CodeGen.setAttr(attrs.c_str());
254
255 if (!OutputFilename.empty()) {
256 size_t len = 0;
257 std::string ErrorInfo;
258 const void *Code =
259 CodeGen.compile(&len, DisableInline, DisableGVNLoadPRE,
260 DisableLTOVectorization, ErrorInfo);
261 if (!Code) {
262 errs() << argv[0]
263 << ": error compiling the code: " << ErrorInfo << "\n";
264 return 1;
265 }
266
267 std::error_code EC;
268 raw_fd_ostream FileStream(OutputFilename, EC, sys::fs::F_None);
269 if (EC) {
270 errs() << argv[0] << ": error opening the file '" << OutputFilename
271 << "': " << EC.message() << "\n";
272 return 1;
273 }
274
275 FileStream.write(reinterpret_cast<const char *>(Code), len);
276 } else {
277 std::string ErrorInfo;
278 const char *OutputName = nullptr;
279 if (!CodeGen.compile_to_file(&OutputName, DisableInline,
280 DisableGVNLoadPRE, DisableLTOVectorization,
281 ErrorInfo)) {
282 errs() << argv[0]
283 << ": error compiling the code: " << ErrorInfo
284 << "\n";
285 return 1;
286 }
287
288 outs() << "Wrote native object file '" << OutputName << "'\n";
289 }
290
291 return 0;
292 }
293