llvm-lto.cpp revision 438900938c3ac9d7fac2dd5d2c85ca4b9b2e35f7 
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/CodeGen/CommandFlags.h"
16#include "llvm/LTO/LTOCodeGenerator.h"
17#include "llvm/LTO/LTOModule.h"
18#include "llvm/Support/CommandLine.h"
19#include "llvm/Support/ManagedStatic.h"
20#include "llvm/Support/PrettyStackTrace.h"
21#include "llvm/Support/Signals.h"
22#include "llvm/Support/raw_ostream.h"
23#include "llvm/Support/TargetSelect.h"
24
25using namespace llvm;
26
27static cl::opt<bool>
28DisableOpt("disable-opt", cl::init(false),
29  cl::desc("Do not run any optimization passes"));
30
31static cl::opt<bool>
32DisableInline("disable-inlining", cl::init(false),
33  cl::desc("Do not run the inliner pass"));
34
35static cl::opt<bool>
36DisableGVNLoadPRE("disable-gvn-loadpre", cl::init(false),
37  cl::desc("Do not run the GVN load PRE pass"));
38
39static cl::list<std::string>
40InputFilenames(cl::Positional, cl::OneOrMore,
41  cl::desc("<input bitcode files>"));
42
43static cl::opt<std::string>
44OutputFilename("o", cl::init(""),
45  cl::desc("Override output filename"),
46  cl::value_desc("filename"));
47
48static cl::list<std::string>
49ExportedSymbols("exported-symbol",
50  cl::desc("Symbol to export from the resulting object file"),
51  cl::ZeroOrMore);
52
53static cl::list<std::string>
54DSOSymbols("dso-symbol",
55  cl::desc("Symbol to put in the symtab in the resulting dso"),
56  cl::ZeroOrMore);
57
58int main(int argc, char **argv) {
59  // Print a stack trace if we signal out.
60  sys::PrintStackTraceOnErrorSignal();
61  PrettyStackTraceProgram X(argc, argv);
62
63  llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
64  cl::ParseCommandLineOptions(argc, argv, "llvm LTO linker\n");
65
66  // Initialize the configured targets.
67  InitializeAllTargets();
68  InitializeAllTargetMCs();
69  InitializeAllAsmPrinters();
70  InitializeAllAsmParsers();
71
72  // set up the TargetOptions for the machine
73  TargetOptions Options;
74  Options.LessPreciseFPMADOption = EnableFPMAD;
75  Options.NoFramePointerElim = DisableFPElim;
76  Options.AllowFPOpFusion = FuseFPOps;
77  Options.UnsafeFPMath = EnableUnsafeFPMath;
78  Options.NoInfsFPMath = EnableNoInfsFPMath;
79  Options.NoNaNsFPMath = EnableNoNaNsFPMath;
80  Options.HonorSignDependentRoundingFPMathOption =
81    EnableHonorSignDependentRoundingFPMath;
82  Options.UseSoftFloat = GenerateSoftFloatCalls;
83  if (FloatABIForCalls != FloatABI::Default)
84    Options.FloatABIType = FloatABIForCalls;
85  Options.NoZerosInBSS = DontPlaceZerosInBSS;
86  Options.GuaranteedTailCallOpt = EnableGuaranteedTailCallOpt;
87  Options.DisableTailCalls = DisableTailCalls;
88  Options.StackAlignmentOverride = OverrideStackAlignment;
89  Options.TrapFuncName = TrapFuncName;
90  Options.PositionIndependentExecutable = EnablePIE;
91  Options.EnableSegmentedStacks = SegmentedStacks;
92  Options.UseInitArray = UseInitArray;
93
94  unsigned BaseArg = 0;
95
96  LTOCodeGenerator CodeGen;
97
98  CodeGen.setCodePICModel(LTO_CODEGEN_PIC_MODEL_DYNAMIC);
99  CodeGen.setDebugInfo(LTO_DEBUG_MODEL_DWARF);
100  CodeGen.setTargetOptions(Options);
101
102  for (unsigned i = BaseArg; i < InputFilenames.size(); ++i) {
103    std::string error;
104    OwningPtr<LTOModule> Module(LTOModule::makeLTOModule(InputFilenames[i].c_str(),
105                                                         Options, error));
106    if (!error.empty()) {
107      errs() << argv[0] << ": error loading file '" << InputFilenames[i]
108             << "': " << error << "\n";
109      return 1;
110    }
111
112
113    if (!CodeGen.addModule(Module.get(), error)) {
114      errs() << argv[0] << ": error adding file '" << InputFilenames[i]
115             << "': " << error << "\n";
116      return 1;
117    }
118  }
119
120  // Add all the exported symbols to the table of symbols to preserve.
121  for (unsigned i = 0; i < ExportedSymbols.size(); ++i)
122    CodeGen.addMustPreserveSymbol(ExportedSymbols[i].c_str());
123
124  // Add all the dso symbols to the table of symbols to expose.
125  for (unsigned i = 0; i < DSOSymbols.size(); ++i)
126    CodeGen.addDSOSymbol(DSOSymbols[i].c_str());
127
128  if (!OutputFilename.empty()) {
129    size_t len = 0;
130    std::string ErrorInfo;
131    const void *Code = CodeGen.compile(&len, DisableOpt, DisableInline,
132                                       DisableGVNLoadPRE, ErrorInfo);
133    if (Code == NULL) {
134      errs() << argv[0]
135             << ": error compiling the code: " << ErrorInfo << "\n";
136      return 1;
137    }
138
139    raw_fd_ostream FileStream(OutputFilename.c_str(), ErrorInfo);
140    if (!ErrorInfo.empty()) {
141      errs() << argv[0] << ": error opening the file '" << OutputFilename
142             << "': " << ErrorInfo << "\n";
143      return 1;
144    }
145
146    FileStream.write(reinterpret_cast<const char *>(Code), len);
147  } else {
148    std::string ErrorInfo;
149    const char *OutputName = NULL;
150    if (!CodeGen.compile_to_file(&OutputName, DisableOpt, DisableInline,
151                                 DisableGVNLoadPRE, ErrorInfo)) {
152      errs() << argv[0]
153             << ": error compiling the code: " << ErrorInfo
154             << "\n";
155      return 1;
156    }
157
158    outs() << "Wrote native object file '" << OutputName << "'\n";
159  }
160
161  return 0;
162}
163