llc.cpp revision 204642 
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/PassManager.h"
19#include "llvm/Pass.h"
20#include "llvm/ADT/Triple.h"
21#include "llvm/Analysis/Verifier.h"
22#include "llvm/Support/IRReader.h"
23#include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
24#include "llvm/CodeGen/LinkAllCodegenComponents.h"
25#include "llvm/Config/config.h"
26#include "llvm/LinkAllVMCore.h"
27#include "llvm/Support/CommandLine.h"
28#include "llvm/Support/Debug.h"
29#include "llvm/Support/FileUtilities.h"
30#include "llvm/Support/FormattedStream.h"
31#include "llvm/Support/ManagedStatic.h"
32#include "llvm/Support/MemoryBuffer.h"
33#include "llvm/Support/PluginLoader.h"
34#include "llvm/Support/PrettyStackTrace.h"
35#include "llvm/System/Host.h"
36#include "llvm/System/Signals.h"
37#include "llvm/Target/SubtargetFeature.h"
38#include "llvm/Target/TargetData.h"
39#include "llvm/Target/TargetMachine.h"
40#include "llvm/Target/TargetRegistry.h"
41#include "llvm/Target/TargetSelect.h"
42#include "llvm/Transforms/Scalar.h"
43#include <memory>
44using namespace llvm;
45
46// General options for llc.  Other pass-specific options are specified
47// within the corresponding llc passes, and target-specific options
48// and back-end code generation options are specified with the target machine.
49//
50static cl::opt<std::string>
51InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
52
53static cl::opt<std::string>
54OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
55
56static cl::opt<bool>
57Force("f", cl::desc("Enable binary output on terminals"));
58
59// Determine optimization level.
60static cl::opt<char>
61OptLevel("O",
62         cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
63                  "(default = '-O2')"),
64         cl::Prefix,
65         cl::ZeroOrMore,
66         cl::init(' '));
67
68static cl::opt<std::string>
69TargetTriple("mtriple", cl::desc("Override target triple for module"));
70
71static cl::opt<std::string>
72MArch("march", cl::desc("Architecture to generate code for (see --version)"));
73
74static cl::opt<std::string>
75MCPU("mcpu",
76  cl::desc("Target a specific cpu type (-mcpu=help for details)"),
77  cl::value_desc("cpu-name"),
78  cl::init(""));
79
80static cl::list<std::string>
81MAttrs("mattr",
82  cl::CommaSeparated,
83  cl::desc("Target specific attributes (-mattr=help for details)"),
84  cl::value_desc("a1,+a2,-a3,..."));
85
86cl::opt<TargetMachine::CodeGenFileType>
87FileType("filetype", cl::init(TargetMachine::CGFT_AssemblyFile),
88  cl::desc("Choose a file type (not all types are supported by all targets):"),
89  cl::values(
90       clEnumValN(TargetMachine::CGFT_AssemblyFile, "asm",
91                  "Emit an assembly ('.s') file"),
92       clEnumValN(TargetMachine::CGFT_ObjectFile, "obj",
93                  "Emit a native object ('.o') file [experimental]"),
94       clEnumValN(TargetMachine::CGFT_Null, "null",
95                  "Emit nothing, for performance testing"),
96       clEnumValEnd));
97
98cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
99                       cl::desc("Do not verify input module"));
100
101
102static cl::opt<bool>
103DisableRedZone("disable-red-zone",
104  cl::desc("Do not emit code that uses the red zone."),
105  cl::init(false));
106
107static cl::opt<bool>
108NoImplicitFloats("no-implicit-float",
109  cl::desc("Don't generate implicit floating point instructions (x86-only)"),
110  cl::init(false));
111
112// GetFileNameRoot - Helper function to get the basename of a filename.
113static inline std::string
114GetFileNameRoot(const std::string &InputFilename) {
115  std::string IFN = InputFilename;
116  std::string outputFilename;
117  int Len = IFN.length();
118  if ((Len > 2) &&
119      IFN[Len-3] == '.' &&
120      ((IFN[Len-2] == 'b' && IFN[Len-1] == 'c') ||
121       (IFN[Len-2] == 'l' && IFN[Len-1] == 'l'))) {
122    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
123  } else {
124    outputFilename = IFN;
125  }
126  return outputFilename;
127}
128
129static formatted_raw_ostream *GetOutputStream(const char *TargetName,
130                                              const char *ProgName) {
131  if (OutputFilename != "") {
132    if (OutputFilename == "-")
133      return &fouts();
134
135    // Make sure that the Out file gets unlinked from the disk if we get a
136    // SIGINT
137    sys::RemoveFileOnSignal(sys::Path(OutputFilename));
138
139    std::string error;
140    raw_fd_ostream *FDOut =
141      new raw_fd_ostream(OutputFilename.c_str(), error,
142                         raw_fd_ostream::F_Binary);
143    if (!error.empty()) {
144      errs() << error << '\n';
145      delete FDOut;
146      return 0;
147    }
148    formatted_raw_ostream *Out =
149      new formatted_raw_ostream(*FDOut, formatted_raw_ostream::DELETE_STREAM);
150
151    return Out;
152  }
153
154  if (InputFilename == "-") {
155    OutputFilename = "-";
156    return &fouts();
157  }
158
159  OutputFilename = GetFileNameRoot(InputFilename);
160
161  bool Binary = false;
162  switch (FileType) {
163  default: assert(0 && "Unknown file type");
164  case TargetMachine::CGFT_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::CGFT_ObjectFile:
176    OutputFilename += ".o";
177    Binary = true;
178    break;
179  case TargetMachine::CGFT_Null:
180    OutputFilename += ".null";
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
212  // Enable debug stream buffering.
213  EnableDebugBuffering = true;
214
215  LLVMContext &Context = getGlobalContext();
216  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
217
218  // Initialize targets first, so that --version shows registered targets.
219  InitializeAllTargets();
220  InitializeAllAsmPrinters();
221
222  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
223
224  // Load the module to be compiled...
225  SMDiagnostic Err;
226  std::auto_ptr<Module> M;
227
228  M.reset(ParseIRFile(InputFilename, Err, Context));
229  if (M.get() == 0) {
230    Err.Print(argv[0], errs());
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': OLvl = CodeGenOpt::Less; break;
304  case '2': OLvl = CodeGenOpt::Default; break;
305  case '3': OLvl = CodeGenOpt::Aggressive; break;
306  }
307
308  // Request that addPassesToEmitFile run the Verifier after running
309  // passes which modify the IR.
310#ifndef NDEBUG
311  bool DisableVerify = false;
312#else
313  bool DisableVerify = true;
314#endif
315
316  // If this target requires addPassesToEmitWholeFile, do it now.  This is
317  // used by strange things like the C backend.
318  if (Target.WantsWholeFile()) {
319    PassManager PM;
320
321    // Add the target data from the target machine, if it exists, or the module.
322    if (const TargetData *TD = Target.getTargetData())
323      PM.add(new TargetData(*TD));
324    else
325      PM.add(new TargetData(&mod));
326
327    if (!NoVerify)
328      PM.add(createVerifierPass());
329
330    // Ask the target to add backend passes as necessary.
331    if (Target.addPassesToEmitWholeFile(PM, *Out, FileType, OLvl,
332                                        DisableVerify)) {
333      errs() << argv[0] << ": target does not support generation of this"
334             << " file type!\n";
335      if (Out != &fouts()) delete Out;
336      // And the Out file is empty and useless, so remove it now.
337      sys::Path(OutputFilename).eraseFromDisk();
338      return 1;
339    }
340    PM.run(mod);
341  } else {
342    // Build up all of the passes that we want to do to the module.
343    FunctionPassManager Passes(M.get());
344
345    // Add the target data from the target machine, if it exists, or the module.
346    if (const TargetData *TD = Target.getTargetData())
347      Passes.add(new TargetData(*TD));
348    else
349      Passes.add(new TargetData(&mod));
350
351#ifndef NDEBUG
352    if (!NoVerify)
353      Passes.add(createVerifierPass());
354#endif
355
356    // Override default to generate verbose assembly.
357    Target.setAsmVerbosityDefault(true);
358
359    if (Target.addPassesToEmitFile(Passes, *Out, FileType, OLvl,
360                                   DisableVerify)) {
361      errs() << argv[0] << ": target does not support generation of this"
362             << " file type!\n";
363      if (Out != &fouts()) delete Out;
364      // And the Out file is empty and useless, so remove it now.
365      sys::Path(OutputFilename).eraseFromDisk();
366      return 1;
367    }
368
369    Passes.doInitialization();
370
371    // Run our queue of passes all at once now, efficiently.
372    // TODO: this could lazily stream functions out of the module.
373    for (Module::iterator I = mod.begin(), E = mod.end(); I != E; ++I)
374      if (!I->isDeclaration()) {
375        if (DisableRedZone)
376          I->addFnAttr(Attribute::NoRedZone);
377        if (NoImplicitFloats)
378          I->addFnAttr(Attribute::NoImplicitFloat);
379        Passes.run(*I);
380      }
381
382    Passes.doFinalization();
383  }
384
385  // Delete the ostream if it's not a stdout stream
386  if (Out != &fouts()) delete Out;
387
388  return 0;
389}
390