llc.cpp revision c58d01b235fb6aba9edb49f6dbe08edaa756a873 
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/Support/IRReader.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/Debug.h"
32#include "llvm/Support/FileUtilities.h"
33#include "llvm/Support/FormattedStream.h"
34#include "llvm/Support/ManagedStatic.h"
35#include "llvm/Support/MemoryBuffer.h"
36#include "llvm/Support/PluginLoader.h"
37#include "llvm/Support/PrettyStackTrace.h"
38#include "llvm/System/Host.h"
39#include "llvm/System/Signals.h"
40#include "llvm/Target/SubtargetFeature.h"
41#include "llvm/Target/TargetData.h"
42#include "llvm/Target/TargetMachine.h"
43#include "llvm/Target/TargetRegistry.h"
44#include "llvm/Target/TargetSelect.h"
45#include "llvm/Transforms/Scalar.h"
46#include <memory>
47using namespace llvm;
48
49// General options for llc.  Other pass-specific options are specified
50// within the corresponding llc passes, and target-specific options
51// and back-end code generation options are specified with the target machine.
52//
53static cl::opt<std::string>
54InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
55
56static cl::opt<std::string>
57OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
58
59static cl::opt<bool>
60Force("f", cl::desc("Enable binary output on terminals"));
61
62// Determine optimization level.
63static cl::opt<char>
64OptLevel("O",
65         cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
66                  "(default = '-O2')"),
67         cl::Prefix,
68         cl::ZeroOrMore,
69         cl::init(' '));
70
71static cl::opt<std::string>
72TargetTriple("mtriple", cl::desc("Override target triple for module"));
73
74static cl::opt<std::string>
75MArch("march", cl::desc("Architecture to generate code for (see --version)"));
76
77static cl::opt<std::string>
78MCPU("mcpu",
79  cl::desc("Target a specific cpu type (-mcpu=help for details)"),
80  cl::value_desc("cpu-name"),
81  cl::init(""));
82
83static cl::list<std::string>
84MAttrs("mattr",
85  cl::CommaSeparated,
86  cl::desc("Target specific attributes (-mattr=help for details)"),
87  cl::value_desc("a1,+a2,-a3,..."));
88
89cl::opt<TargetMachine::CodeGenFileType>
90FileType("filetype", cl::init(TargetMachine::AssemblyFile),
91  cl::desc("Choose a file type (not all types are supported by all targets):"),
92  cl::values(
93       clEnumValN(TargetMachine::AssemblyFile, "asm",
94                  "Emit an assembly ('.s') file"),
95       clEnumValN(TargetMachine::ObjectFile, "obj",
96                  "Emit a native object ('.o') file [experimental]"),
97       clEnumValN(TargetMachine::DynamicLibrary, "dynlib",
98                  "Emit a native dynamic library ('.so') file"
99                  " [experimental]"),
100       clEnumValEnd));
101
102cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
103                       cl::desc("Do not verify input module"));
104
105
106static cl::opt<bool>
107DisableRedZone("disable-red-zone",
108  cl::desc("Do not emit code that uses the red zone."),
109  cl::init(false));
110
111static cl::opt<bool>
112NoImplicitFloats("no-implicit-float",
113  cl::desc("Don't generate implicit floating point instructions (x86-only)"),
114  cl::init(false));
115
116// GetFileNameRoot - Helper function to get the basename of a filename.
117static inline std::string
118GetFileNameRoot(const std::string &InputFilename) {
119  std::string IFN = InputFilename;
120  std::string outputFilename;
121  int Len = IFN.length();
122  if ((Len > 2) &&
123      IFN[Len-3] == '.' &&
124      ((IFN[Len-2] == 'b' && IFN[Len-1] == 'c') ||
125       (IFN[Len-2] == 'l' && IFN[Len-1] == 'l'))) {
126    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
127  } else {
128    outputFilename = IFN;
129  }
130  return outputFilename;
131}
132
133static formatted_raw_ostream *GetOutputStream(const char *TargetName,
134                                              const char *ProgName) {
135  if (OutputFilename != "") {
136    if (OutputFilename == "-")
137      return &fouts();
138
139    // Make sure that the Out file gets unlinked from the disk if we get a
140    // SIGINT
141    sys::RemoveFileOnSignal(sys::Path(OutputFilename));
142
143    std::string error;
144    raw_fd_ostream *FDOut =
145      new raw_fd_ostream(OutputFilename.c_str(), error,
146                         raw_fd_ostream::F_Binary);
147    if (!error.empty()) {
148      errs() << error << '\n';
149      delete FDOut;
150      return 0;
151    }
152    formatted_raw_ostream *Out =
153      new formatted_raw_ostream(*FDOut, formatted_raw_ostream::DELETE_STREAM);
154
155    return Out;
156  }
157
158  if (InputFilename == "-") {
159    OutputFilename = "-";
160    return &fouts();
161  }
162
163  OutputFilename = GetFileNameRoot(InputFilename);
164
165  bool Binary = false;
166  switch (FileType) {
167  case TargetMachine::AssemblyFile:
168    if (TargetName[0] == 'c') {
169      if (TargetName[1] == 0)
170        OutputFilename += ".cbe.c";
171      else if (TargetName[1] == 'p' && TargetName[2] == 'p')
172        OutputFilename += ".cpp";
173      else
174        OutputFilename += ".s";
175    } else
176      OutputFilename += ".s";
177    break;
178  case TargetMachine::ObjectFile:
179    OutputFilename += ".o";
180    Binary = true;
181    break;
182  case TargetMachine::DynamicLibrary:
183    OutputFilename += LTDL_SHLIB_EXT;
184    Binary = true;
185    break;
186  }
187
188  // Make sure that the Out file gets unlinked from the disk if we get a
189  // SIGINT
190  sys::RemoveFileOnSignal(sys::Path(OutputFilename));
191
192  std::string error;
193  unsigned OpenFlags = 0;
194  if (Binary) OpenFlags |= raw_fd_ostream::F_Binary;
195  raw_fd_ostream *FDOut = new raw_fd_ostream(OutputFilename.c_str(), error,
196                                             OpenFlags);
197  if (!error.empty()) {
198    errs() << error << '\n';
199    delete FDOut;
200    return 0;
201  }
202
203  formatted_raw_ostream *Out =
204    new formatted_raw_ostream(*FDOut, formatted_raw_ostream::DELETE_STREAM);
205
206  return Out;
207}
208
209// main - Entry point for the llc compiler.
210//
211int main(int argc, char **argv) {
212  sys::PrintStackTraceOnErrorSignal();
213  PrettyStackTraceProgram X(argc, argv);
214
215  // Enable debug stream buffering.
216  EnableDebugBuffering = true;
217
218  LLVMContext &Context = getGlobalContext();
219  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
220
221  // Initialize targets first, so that --version shows registered targets.
222  InitializeAllTargets();
223  InitializeAllAsmPrinters();
224
225  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
226
227  // Load the module to be compiled...
228  SMDiagnostic Err;
229  std::auto_ptr<Module> M;
230
231  M.reset(ParseIRFile(InputFilename, Err, Context));
232  if (M.get() == 0) {
233    Err.Print(argv[0], errs());
234    return 1;
235  }
236  Module &mod = *M.get();
237
238  // If we are supposed to override the target triple, do so now.
239  if (!TargetTriple.empty())
240    mod.setTargetTriple(TargetTriple);
241
242  Triple TheTriple(mod.getTargetTriple());
243  if (TheTriple.getTriple().empty())
244    TheTriple.setTriple(sys::getHostTriple());
245
246  // Allocate target machine.  First, check whether the user has explicitly
247  // specified an architecture to compile for. If so we have to look it up by
248  // name, because it might be a backend that has no mapping to a target triple.
249  const Target *TheTarget = 0;
250  if (!MArch.empty()) {
251    for (TargetRegistry::iterator it = TargetRegistry::begin(),
252           ie = TargetRegistry::end(); it != ie; ++it) {
253      if (MArch == it->getName()) {
254        TheTarget = &*it;
255        break;
256      }
257    }
258
259    if (!TheTarget) {
260      errs() << argv[0] << ": error: invalid target '" << MArch << "'.\n";
261      return 1;
262    }
263
264    // Adjust the triple to match (if known), otherwise stick with the
265    // module/host triple.
266    Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
267    if (Type != Triple::UnknownArch)
268      TheTriple.setArch(Type);
269  } else {
270    std::string Err;
271    TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Err);
272    if (TheTarget == 0) {
273      errs() << argv[0] << ": error auto-selecting target for module '"
274             << Err << "'.  Please use the -march option to explicitly "
275             << "pick a target.\n";
276      return 1;
277    }
278  }
279
280  // Package up features to be passed to target/subtarget
281  std::string FeaturesStr;
282  if (MCPU.size() || MAttrs.size()) {
283    SubtargetFeatures Features;
284    Features.setCPU(MCPU);
285    for (unsigned i = 0; i != MAttrs.size(); ++i)
286      Features.AddFeature(MAttrs[i]);
287    FeaturesStr = Features.getString();
288  }
289
290  std::auto_ptr<TargetMachine>
291    target(TheTarget->createTargetMachine(TheTriple.getTriple(), FeaturesStr));
292  assert(target.get() && "Could not allocate target machine!");
293  TargetMachine &Target = *target.get();
294
295  // Figure out where we are going to send the output...
296  formatted_raw_ostream *Out = GetOutputStream(TheTarget->getName(), argv[0]);
297  if (Out == 0) return 1;
298
299  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
300  switch (OptLevel) {
301  default:
302    errs() << argv[0] << ": invalid optimization level.\n";
303    return 1;
304  case ' ': break;
305  case '0': OLvl = CodeGenOpt::None; break;
306  case '1': OLvl = CodeGenOpt::Less; break;
307  case '2': OLvl = CodeGenOpt::Default; break;
308  case '3': OLvl = CodeGenOpt::Aggressive; break;
309  }
310
311  // If this target requires addPassesToEmitWholeFile, do it now.  This is
312  // used by strange things like the C backend.
313  if (Target.WantsWholeFile()) {
314    PassManager PM;
315
316    // Add the target data from the target machine, if it exists, or the module.
317    if (const TargetData *TD = Target.getTargetData())
318      PM.add(new TargetData(*TD));
319    else
320      PM.add(new TargetData(&mod));
321
322    if (!NoVerify)
323      PM.add(createVerifierPass());
324
325    // Ask the target to add backend passes as necessary.
326    if (Target.addPassesToEmitWholeFile(PM, *Out, FileType, OLvl)) {
327      errs() << argv[0] << ": target does not support generation of this"
328             << " file type!\n";
329      if (Out != &fouts()) delete Out;
330      // And the Out file is empty and useless, so remove it now.
331      sys::Path(OutputFilename).eraseFromDisk();
332      return 1;
333    }
334    PM.run(mod);
335  } else {
336    // Build up all of the passes that we want to do to the module.
337    ExistingModuleProvider Provider(M.release());
338    FunctionPassManager Passes(&Provider);
339
340    // Add the target data from the target machine, if it exists, or the module.
341    if (const TargetData *TD = Target.getTargetData())
342      Passes.add(new TargetData(*TD));
343    else
344      Passes.add(new TargetData(&mod));
345
346#ifndef NDEBUG
347    if (!NoVerify)
348      Passes.add(createVerifierPass());
349#endif
350
351    // Ask the target to add backend passes as necessary.
352    ObjectCodeEmitter *OCE = 0;
353
354    // Override default to generate verbose assembly.
355    Target.setAsmVerbosityDefault(true);
356
357    switch (Target.addPassesToEmitFile(Passes, *Out, FileType, OLvl)) {
358    default:
359      assert(0 && "Invalid file model!");
360      return 1;
361    case FileModel::Error:
362      errs() << argv[0] << ": target does not support generation of this"
363             << " file type!\n";
364      if (Out != &fouts()) delete Out;
365      // And the Out file is empty and useless, so remove it now.
366      sys::Path(OutputFilename).eraseFromDisk();
367      return 1;
368    case FileModel::AsmFile:
369      break;
370    case FileModel::MachOFile:
371      OCE = AddMachOWriter(Passes, *Out, Target);
372      break;
373    case FileModel::ElfFile:
374      OCE = AddELFWriter(Passes, *Out, Target);
375      break;
376    }
377
378    if (Target.addPassesToEmitFileFinish(Passes, OCE, OLvl)) {
379      errs() << argv[0] << ": target does not support generation of this"
380             << " file type!\n";
381      if (Out != &fouts()) delete Out;
382      // And the Out file is empty and useless, so remove it now.
383      sys::Path(OutputFilename).eraseFromDisk();
384      return 1;
385    }
386
387    Passes.doInitialization();
388
389    // Run our queue of passes all at once now, efficiently.
390    // TODO: this could lazily stream functions out of the module.
391    for (Module::iterator I = mod.begin(), E = mod.end(); I != E; ++I)
392      if (!I->isDeclaration()) {
393        if (DisableRedZone)
394          I->addFnAttr(Attribute::NoRedZone);
395        if (NoImplicitFloats)
396          I->addFnAttr(Attribute::NoImplicitFloat);
397        Passes.run(*I);
398      }
399
400    Passes.doFinalization();
401  }
402
403  // Delete the ostream if it's not a stdout stream
404  if (Out != &fouts()) delete Out;
405
406  return 0;
407}
408