llc.cpp revision baa26395ccf17fc988bb9cf62d6659ca8415ece9 
1//===-- llc.cpp - Implement the LLVM Native Code Generator ----------------===//
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 is the llc code generator driver. It provides a convenient
11// command-line interface for generating native assembly-language code
12// or C code, given LLVM bitcode.
13//
14//===----------------------------------------------------------------------===//
15
16#include "llvm/LLVMContext.h"
17#include "llvm/Module.h"
18#include "llvm/ModuleProvider.h"
19#include "llvm/PassManager.h"
20#include "llvm/Pass.h"
21#include "llvm/ADT/Triple.h"
22#include "llvm/Analysis/Verifier.h"
23#include "llvm/Bitcode/ReaderWriter.h"
24#include "llvm/CodeGen/FileWriters.h"
25#include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
26#include "llvm/CodeGen/LinkAllCodegenComponents.h"
27#include "llvm/CodeGen/ObjectCodeEmitter.h"
28#include "llvm/Config/config.h"
29#include "llvm/LinkAllVMCore.h"
30#include "llvm/Support/CommandLine.h"
31#include "llvm/Support/FileUtilities.h"
32#include "llvm/Support/FormattedStream.h"
33#include "llvm/Support/ManagedStatic.h"
34#include "llvm/Support/MemoryBuffer.h"
35#include "llvm/Support/PluginLoader.h"
36#include "llvm/Support/PrettyStackTrace.h"
37#include "llvm/System/Host.h"
38#include "llvm/System/Signals.h"
39#include "llvm/Target/SubtargetFeature.h"
40#include "llvm/Target/TargetData.h"
41#include "llvm/Target/TargetMachine.h"
42#include "llvm/Target/TargetRegistry.h"
43#include "llvm/Target/TargetSelect.h"
44#include "llvm/Transforms/Scalar.h"
45#include <memory>
46using namespace llvm;
47
48// General options for llc.  Other pass-specific options are specified
49// within the corresponding llc passes, and target-specific options
50// and back-end code generation options are specified with the target machine.
51//
52static cl::opt<std::string>
53InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
54
55static cl::opt<std::string>
56OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
57
58static cl::opt<bool>
59Force("f", cl::desc("Enable binary output on terminals"));
60
61// Determine optimization level.
62static cl::opt<char>
63OptLevel("O",
64         cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
65                  "(default = '-O2')"),
66         cl::Prefix,
67         cl::ZeroOrMore,
68         cl::init(' '));
69
70static cl::opt<std::string>
71TargetTriple("mtriple", cl::desc("Override target triple for module"));
72
73static cl::opt<std::string>
74MArch("march", cl::desc("Architecture to generate code for (see --version)"));
75
76static cl::opt<std::string>
77MCPU("mcpu",
78  cl::desc("Target a specific cpu type (-mcpu=help for details)"),
79  cl::value_desc("cpu-name"),
80  cl::init(""));
81
82static cl::list<std::string>
83MAttrs("mattr",
84  cl::CommaSeparated,
85  cl::desc("Target specific attributes (-mattr=help for details)"),
86  cl::value_desc("a1,+a2,-a3,..."));
87
88cl::opt<TargetMachine::CodeGenFileType>
89FileType("filetype", cl::init(TargetMachine::AssemblyFile),
90  cl::desc("Choose a file type (not all types are supported by all targets):"),
91  cl::values(
92       clEnumValN(TargetMachine::AssemblyFile, "asm",
93                  "Emit an assembly ('.s') file"),
94       clEnumValN(TargetMachine::ObjectFile, "obj",
95                  "Emit a native object ('.o') file [experimental]"),
96       clEnumValN(TargetMachine::DynamicLibrary, "dynlib",
97                  "Emit a native dynamic library ('.so') file"
98                  " [experimental]"),
99       clEnumValEnd));
100
101cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
102                       cl::desc("Do not verify input module"));
103
104
105static cl::opt<bool>
106DisableRedZone("disable-red-zone",
107  cl::desc("Do not emit code that uses the red zone."),
108  cl::init(false));
109
110static cl::opt<bool>
111NoImplicitFloats("no-implicit-float",
112  cl::desc("Don't generate implicit floating point instructions (x86-only)"),
113  cl::init(false));
114
115// GetFileNameRoot - Helper function to get the basename of a filename.
116static inline std::string
117GetFileNameRoot(const std::string &InputFilename) {
118  std::string IFN = InputFilename;
119  std::string outputFilename;
120  int Len = IFN.length();
121  if ((Len > 2) &&
122      IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c') {
123    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
124  } else {
125    outputFilename = IFN;
126  }
127  return outputFilename;
128}
129
130static formatted_raw_ostream *GetOutputStream(const char *TargetName,
131                                              const char *ProgName) {
132  if (OutputFilename != "") {
133    if (OutputFilename == "-")
134      return &fouts();
135
136    // Make sure that the Out file gets unlinked from the disk if we get a
137    // SIGINT
138    sys::RemoveFileOnSignal(sys::Path(OutputFilename));
139
140    std::string error;
141    raw_fd_ostream *FDOut =
142      new raw_fd_ostream(OutputFilename.c_str(), error,
143                         raw_fd_ostream::F_Binary);
144    if (!error.empty()) {
145      errs() << error << '\n';
146      delete FDOut;
147      return 0;
148    }
149    formatted_raw_ostream *Out =
150      new formatted_raw_ostream(*FDOut, formatted_raw_ostream::DELETE_STREAM);
151
152    return Out;
153  }
154
155  if (InputFilename == "-") {
156    OutputFilename = "-";
157    return &fouts();
158  }
159
160  OutputFilename = GetFileNameRoot(InputFilename);
161
162  bool Binary = false;
163  switch (FileType) {
164  case TargetMachine::AssemblyFile:
165    if (TargetName[0] == 'c') {
166      if (TargetName[1] == 0)
167        OutputFilename += ".cbe.c";
168      else if (TargetName[1] == 'p' && TargetName[2] == 'p')
169        OutputFilename += ".cpp";
170      else
171        OutputFilename += ".s";
172    } else
173      OutputFilename += ".s";
174    break;
175  case TargetMachine::ObjectFile:
176    OutputFilename += ".o";
177    Binary = true;
178    break;
179  case TargetMachine::DynamicLibrary:
180    OutputFilename += LTDL_SHLIB_EXT;
181    Binary = true;
182    break;
183  }
184
185  // Make sure that the Out file gets unlinked from the disk if we get a
186  // SIGINT
187  sys::RemoveFileOnSignal(sys::Path(OutputFilename));
188
189  std::string error;
190  unsigned OpenFlags = 0;
191  if (Binary) OpenFlags |= raw_fd_ostream::F_Binary;
192  raw_fd_ostream *FDOut = new raw_fd_ostream(OutputFilename.c_str(), error,
193                                             OpenFlags);
194  if (!error.empty()) {
195    errs() << error << '\n';
196    delete FDOut;
197    return 0;
198  }
199
200  formatted_raw_ostream *Out =
201    new formatted_raw_ostream(*FDOut, formatted_raw_ostream::DELETE_STREAM);
202
203  return Out;
204}
205
206// main - Entry point for the llc compiler.
207//
208int main(int argc, char **argv) {
209  sys::PrintStackTraceOnErrorSignal();
210  PrettyStackTraceProgram X(argc, argv);
211  LLVMContext &Context = getGlobalContext();
212  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
213
214  // Initialize targets first.
215  InitializeAllTargets();
216  InitializeAllAsmPrinters();
217
218  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
219
220  // Load the module to be compiled...
221  std::string ErrorMessage;
222  std::auto_ptr<Module> M;
223
224  std::auto_ptr<MemoryBuffer> Buffer(
225                   MemoryBuffer::getFileOrSTDIN(InputFilename, &ErrorMessage));
226  if (Buffer.get())
227    M.reset(ParseBitcodeFile(Buffer.get(), Context, &ErrorMessage));
228  if (M.get() == 0) {
229    errs() << argv[0] << ": bitcode didn't read correctly.\n";
230    errs() << "Reason: " << ErrorMessage << "\n";
231    return 1;
232  }
233  Module &mod = *M.get();
234
235  // If we are supposed to override the target triple, do so now.
236  if (!TargetTriple.empty())
237    mod.setTargetTriple(TargetTriple);
238
239  Triple TheTriple(mod.getTargetTriple());
240  if (TheTriple.getTriple().empty())
241    TheTriple.setTriple(sys::getHostTriple());
242
243  // Allocate target machine.  First, check whether the user has explicitly
244  // specified an architecture to compile for. If so we have to look it up by
245  // name, because it might be a backend that has no mapping to a target triple.
246  const Target *TheTarget = 0;
247  if (!MArch.empty()) {
248    for (TargetRegistry::iterator it = TargetRegistry::begin(),
249           ie = TargetRegistry::end(); it != ie; ++it) {
250      if (MArch == it->getName()) {
251        TheTarget = &*it;
252        break;
253      }
254    }
255
256    if (!TheTarget) {
257      errs() << argv[0] << ": error: invalid target '" << MArch << "'.\n";
258      return 1;
259    }
260
261    // Adjust the triple to match (if known), otherwise stick with the
262    // module/host triple.
263    Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
264    if (Type != Triple::UnknownArch)
265      TheTriple.setArch(Type);
266  } else {
267    std::string Err;
268    TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Err);
269    if (TheTarget == 0) {
270      errs() << argv[0] << ": error auto-selecting target for module '"
271             << Err << "'.  Please use the -march option to explicitly "
272             << "pick a target.\n";
273      return 1;
274    }
275  }
276
277  // Package up features to be passed to target/subtarget
278  std::string FeaturesStr;
279  if (MCPU.size() || MAttrs.size()) {
280    SubtargetFeatures Features;
281    Features.setCPU(MCPU);
282    for (unsigned i = 0; i != MAttrs.size(); ++i)
283      Features.AddFeature(MAttrs[i]);
284    FeaturesStr = Features.getString();
285  }
286
287  std::auto_ptr<TargetMachine>
288    target(TheTarget->createTargetMachine(TheTriple.getTriple(), FeaturesStr));
289  assert(target.get() && "Could not allocate target machine!");
290  TargetMachine &Target = *target.get();
291
292  // Figure out where we are going to send the output...
293  formatted_raw_ostream *Out = GetOutputStream(TheTarget->getName(), argv[0]);
294  if (Out == 0) return 1;
295
296  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
297  switch (OptLevel) {
298  default:
299    errs() << argv[0] << ": invalid optimization level.\n";
300    return 1;
301  case ' ': break;
302  case '0': OLvl = CodeGenOpt::None; break;
303  case '1':
304  case '2': OLvl = CodeGenOpt::Default; break;
305  case '3': OLvl = CodeGenOpt::Aggressive; break;
306  }
307
308  // If this target requires addPassesToEmitWholeFile, do it now.  This is
309  // used by strange things like the C backend.
310  if (Target.WantsWholeFile()) {
311    PassManager PM;
312
313    // Add the target data from the target machine, if it exists, or the module.
314    if (const TargetData *TD = Target.getTargetData())
315      PM.add(new TargetData(*TD));
316    else
317      PM.add(new TargetData(&mod));
318
319    if (!NoVerify)
320      PM.add(createVerifierPass());
321
322    // Ask the target to add backend passes as necessary.
323    if (Target.addPassesToEmitWholeFile(PM, *Out, FileType, OLvl)) {
324      errs() << argv[0] << ": target does not support generation of this"
325             << " file type!\n";
326      if (Out != &fouts()) delete Out;
327      // And the Out file is empty and useless, so remove it now.
328      sys::Path(OutputFilename).eraseFromDisk();
329      return 1;
330    }
331    PM.run(mod);
332  } else {
333    // Build up all of the passes that we want to do to the module.
334    ExistingModuleProvider Provider(M.release());
335    FunctionPassManager Passes(&Provider);
336
337    // Add the target data from the target machine, if it exists, or the module.
338    if (const TargetData *TD = Target.getTargetData())
339      Passes.add(new TargetData(*TD));
340    else
341      Passes.add(new TargetData(&mod));
342
343#ifndef NDEBUG
344    if (!NoVerify)
345      Passes.add(createVerifierPass());
346#endif
347
348    // Ask the target to add backend passes as necessary.
349    ObjectCodeEmitter *OCE = 0;
350
351    // Override default to generate verbose assembly.
352    Target.setAsmVerbosityDefault(true);
353
354    switch (Target.addPassesToEmitFile(Passes, *Out, FileType, OLvl)) {
355    default:
356      assert(0 && "Invalid file model!");
357      return 1;
358    case FileModel::Error:
359      errs() << argv[0] << ": target does not support generation of this"
360             << " file type!\n";
361      if (Out != &fouts()) delete Out;
362      // And the Out file is empty and useless, so remove it now.
363      sys::Path(OutputFilename).eraseFromDisk();
364      return 1;
365    case FileModel::AsmFile:
366      break;
367    case FileModel::MachOFile:
368      OCE = AddMachOWriter(Passes, *Out, Target);
369      break;
370    case FileModel::ElfFile:
371      OCE = AddELFWriter(Passes, *Out, Target);
372      break;
373    }
374
375    if (Target.addPassesToEmitFileFinish(Passes, OCE, OLvl)) {
376      errs() << argv[0] << ": target does not support generation of this"
377             << " file type!\n";
378      if (Out != &fouts()) delete Out;
379      // And the Out file is empty and useless, so remove it now.
380      sys::Path(OutputFilename).eraseFromDisk();
381      return 1;
382    }
383
384    Passes.doInitialization();
385
386    // Run our queue of passes all at once now, efficiently.
387    // TODO: this could lazily stream functions out of the module.
388    for (Module::iterator I = mod.begin(), E = mod.end(); I != E; ++I)
389      if (!I->isDeclaration()) {
390        if (DisableRedZone)
391          I->addFnAttr(Attribute::NoRedZone);
392        if (NoImplicitFloats)
393          I->addFnAttr(Attribute::NoImplicitFloat);
394        Passes.run(*I);
395      }
396
397    Passes.doFinalization();
398  }
399
400  Out->flush();
401
402  // Delete the ostream if it's not a stdout stream
403  if (Out != &fouts()) delete Out;
404
405  return 0;
406}
407