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::list<std::string>
42 InputFilenames(cl::Positional, cl::OneOrMore,
43 cl::desc("<input bitcode files>"));
44
45 static cl::opt<std::string>
46 OutputFilename("o", cl::init(""),
47 cl::desc("Override output filename"),
48 cl::value_desc("filename"));
49
50 static cl::list<std::string>
51 ExportedSymbols("exported-symbol",
52 cl::desc("Symbol to export from the resulting object file"),
53 cl::ZeroOrMore);
54
55 static cl::list<std::string>
56 DSOSymbols("dso-symbol",
57 cl::desc("Symbol to put in the symtab in the resulting dso"),
58 cl::ZeroOrMore);
59
60 namespace {
61 struct ModuleInfo {
62 std::vector<bool> CanBeHidden;
63 };
64 }
65
main(int argc,char ** argv)66 int main(int argc, char **argv) {
67 // Print a stack trace if we signal out.
68 sys::PrintStackTraceOnErrorSignal();
69 PrettyStackTraceProgram X(argc, argv);
70
71 llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
72 cl::ParseCommandLineOptions(argc, argv, "llvm LTO linker\n");
73
74 // Initialize the configured targets.
75 InitializeAllTargets();
76 InitializeAllTargetMCs();
77 InitializeAllAsmPrinters();
78 InitializeAllAsmParsers();
79
80 // set up the TargetOptions for the machine
81 TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
82
83 unsigned BaseArg = 0;
84
85 LTOCodeGenerator CodeGen;
86
87 switch (RelocModel) {
88 case Reloc::Static:
89 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_STATIC);
90 break;
91 case Reloc::PIC_:
92 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC);
93 break;
94 case Reloc::DynamicNoPIC:
95 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC);
96 break;
97 default:
98 CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DEFAULT);
99 }
100
101 CodeGen.setDebugInfo(LTO_DEBUG_MODEL_DWARF);
102 CodeGen.setTargetOptions(Options);
103
104 llvm::StringSet<llvm::MallocAllocator> DSOSymbolsSet;
105 for (unsigned i = 0; i < DSOSymbols.size(); ++i)
106 DSOSymbolsSet.insert(DSOSymbols[i]);
107
108 std::vector<std::string> KeptDSOSyms;
109
110 for (unsigned i = BaseArg; i < InputFilenames.size(); ++i) {
111 std::string error;
112 std::unique_ptr<LTOModule> Module(
113 LTOModule::createFromFile(InputFilenames[i].c_str(), Options, error));
114 if (!error.empty()) {
115 errs() << argv[0] << ": error loading file '" << InputFilenames[i]
116 << "': " << error << "\n";
117 return 1;
118 }
119
120
121 if (!CodeGen.addModule(Module.get(), error)) {
122 errs() << argv[0] << ": error adding file '" << InputFilenames[i]
123 << "': " << error << "\n";
124 return 1;
125 }
126
127 unsigned NumSyms = Module->getSymbolCount();
128 for (unsigned I = 0; I < NumSyms; ++I) {
129 StringRef Name = Module->getSymbolName(I);
130 if (!DSOSymbolsSet.count(Name))
131 continue;
132 lto_symbol_attributes Attrs = Module->getSymbolAttributes(I);
133 unsigned Scope = Attrs & LTO_SYMBOL_SCOPE_MASK;
134 if (Scope != LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN)
135 KeptDSOSyms.push_back(Name);
136 }
137 }
138
139 // Add all the exported symbols to the table of symbols to preserve.
140 for (unsigned i = 0; i < ExportedSymbols.size(); ++i)
141 CodeGen.addMustPreserveSymbol(ExportedSymbols[i].c_str());
142
143 // Add all the dso symbols to the table of symbols to expose.
144 for (unsigned i = 0; i < KeptDSOSyms.size(); ++i)
145 CodeGen.addMustPreserveSymbol(KeptDSOSyms[i].c_str());
146
147 std::string attrs;
148 for (unsigned i = 0; i < MAttrs.size(); ++i) {
149 if (i > 0)
150 attrs.append(",");
151 attrs.append(MAttrs[i]);
152 }
153
154 if (!attrs.empty())
155 CodeGen.setAttr(attrs.c_str());
156
157 if (!OutputFilename.empty()) {
158 size_t len = 0;
159 std::string ErrorInfo;
160 const void *Code = CodeGen.compile(&len, DisableOpt, DisableInline,
161 DisableGVNLoadPRE, ErrorInfo);
162 if (!Code) {
163 errs() << argv[0]
164 << ": error compiling the code: " << ErrorInfo << "\n";
165 return 1;
166 }
167
168 raw_fd_ostream FileStream(OutputFilename.c_str(), ErrorInfo,
169 sys::fs::F_None);
170 if (!ErrorInfo.empty()) {
171 errs() << argv[0] << ": error opening the file '" << OutputFilename
172 << "': " << ErrorInfo << "\n";
173 return 1;
174 }
175
176 FileStream.write(reinterpret_cast<const char *>(Code), len);
177 } else {
178 std::string ErrorInfo;
179 const char *OutputName = nullptr;
180 if (!CodeGen.compile_to_file(&OutputName, DisableOpt, DisableInline,
181 DisableGVNLoadPRE, ErrorInfo)) {
182 errs() << argv[0]
183 << ": error compiling the code: " << ErrorInfo
184 << "\n";
185 return 1;
186 }
187
188 outs() << "Wrote native object file '" << OutputName << "'\n";
189 }
190
191 return 0;
192 }
193