llc.cpp revision 99dca4fde746eb76253e737cca166261c767412d 
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/Support/CommandLine.h"
27#include "llvm/Support/Debug.h"
28#include "llvm/Support/FormattedStream.h"
29#include "llvm/Support/ManagedStatic.h"
30#include "llvm/Support/PluginLoader.h"
31#include "llvm/Support/PrettyStackTrace.h"
32#include "llvm/System/Host.h"
33#include "llvm/System/Signals.h"
34#include "llvm/Target/SubtargetFeature.h"
35#include "llvm/Target/TargetData.h"
36#include "llvm/Target/TargetMachine.h"
37#include "llvm/Target/TargetRegistry.h"
38#include "llvm/Target/TargetSelect.h"
39#include <memory>
40using namespace llvm;
41
42// General options for llc.  Other pass-specific options are specified
43// within the corresponding llc passes, and target-specific options
44// and back-end code generation options are specified with the target machine.
45//
46static cl::opt<std::string>
47InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
48
49static cl::opt<std::string>
50OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
51
52// Determine optimization level.
53static cl::opt<char>
54OptLevel("O",
55         cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
56                  "(default = '-O2')"),
57         cl::Prefix,
58         cl::ZeroOrMore,
59         cl::init(' '));
60
61static cl::opt<std::string>
62TargetTriple("mtriple", cl::desc("Override target triple for module"));
63
64static cl::opt<std::string>
65MArch("march", cl::desc("Architecture to generate code for (see --version)"));
66
67static cl::opt<std::string>
68MCPU("mcpu",
69  cl::desc("Target a specific cpu type (-mcpu=help for details)"),
70  cl::value_desc("cpu-name"),
71  cl::init(""));
72
73static cl::list<std::string>
74MAttrs("mattr",
75  cl::CommaSeparated,
76  cl::desc("Target specific attributes (-mattr=help for details)"),
77  cl::value_desc("a1,+a2,-a3,..."));
78
79cl::opt<TargetMachine::CodeGenFileType>
80FileType("filetype", cl::init(TargetMachine::CGFT_AssemblyFile),
81  cl::desc("Choose a file type (not all types are supported by all targets):"),
82  cl::values(
83       clEnumValN(TargetMachine::CGFT_AssemblyFile, "asm",
84                  "Emit an assembly ('.s') file"),
85       clEnumValN(TargetMachine::CGFT_ObjectFile, "obj",
86                  "Emit a native object ('.o') file [experimental]"),
87       clEnumValN(TargetMachine::CGFT_Null, "null",
88                  "Emit nothing, for performance testing"),
89       clEnumValEnd));
90
91cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
92                       cl::desc("Do not verify input module"));
93
94
95static cl::opt<bool>
96DisableRedZone("disable-red-zone",
97  cl::desc("Do not emit code that uses the red zone."),
98  cl::init(false));
99
100static cl::opt<bool>
101NoImplicitFloats("no-implicit-float",
102  cl::desc("Don't generate implicit floating point instructions (x86-only)"),
103  cl::init(false));
104
105// GetFileNameRoot - Helper function to get the basename of a filename.
106static inline std::string
107GetFileNameRoot(const std::string &InputFilename) {
108  std::string IFN = InputFilename;
109  std::string outputFilename;
110  int Len = IFN.length();
111  if ((Len > 2) &&
112      IFN[Len-3] == '.' &&
113      ((IFN[Len-2] == 'b' && IFN[Len-1] == 'c') ||
114       (IFN[Len-2] == 'l' && IFN[Len-1] == 'l'))) {
115    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
116  } else {
117    outputFilename = IFN;
118  }
119  return outputFilename;
120}
121
122static formatted_raw_ostream *GetOutputStream(const char *TargetName,
123                                              Triple::OSType OS,
124                                              const char *ProgName) {
125  if (OutputFilename != "") {
126    if (OutputFilename == "-")
127      return &fouts();
128
129    // Make sure that the Out file gets unlinked from the disk if we get a
130    // SIGINT
131    sys::RemoveFileOnSignal(sys::Path(OutputFilename));
132
133    std::string error;
134    raw_fd_ostream *FDOut =
135      new raw_fd_ostream(OutputFilename.c_str(), error,
136                         raw_fd_ostream::F_Binary);
137    if (!error.empty()) {
138      errs() << error << '\n';
139      delete FDOut;
140      return 0;
141    }
142    formatted_raw_ostream *Out =
143      new formatted_raw_ostream(*FDOut, formatted_raw_ostream::DELETE_STREAM);
144
145    return Out;
146  }
147
148  if (InputFilename == "-") {
149    OutputFilename = "-";
150    return &fouts();
151  }
152
153  OutputFilename = GetFileNameRoot(InputFilename);
154
155  bool Binary = false;
156  switch (FileType) {
157  default: assert(0 && "Unknown file type");
158  case TargetMachine::CGFT_AssemblyFile:
159    if (TargetName[0] == 'c') {
160      if (TargetName[1] == 0)
161        OutputFilename += ".cbe.c";
162      else if (TargetName[1] == 'p' && TargetName[2] == 'p')
163        OutputFilename += ".cpp";
164      else
165        OutputFilename += ".s";
166    } else
167      OutputFilename += ".s";
168    break;
169  case TargetMachine::CGFT_ObjectFile:
170    if (OS == Triple::Win32)
171      OutputFilename += ".obj";
172    else
173      OutputFilename += ".o";
174    Binary = true;
175    break;
176  case TargetMachine::CGFT_Null:
177    OutputFilename += ".null";
178    Binary = true;
179    break;
180  }
181
182  // Make sure that the Out file gets unlinked from the disk if we get a
183  // SIGINT
184  sys::RemoveFileOnSignal(sys::Path(OutputFilename));
185
186  std::string error;
187  unsigned OpenFlags = 0;
188  if (Binary) OpenFlags |= raw_fd_ostream::F_Binary;
189  raw_fd_ostream *FDOut = new raw_fd_ostream(OutputFilename.c_str(), error,
190                                             OpenFlags);
191  if (!error.empty()) {
192    errs() << error << '\n';
193    delete FDOut;
194    return 0;
195  }
196
197  formatted_raw_ostream *Out =
198    new formatted_raw_ostream(*FDOut, formatted_raw_ostream::DELETE_STREAM);
199
200  return Out;
201}
202
203// main - Entry point for the llc compiler.
204//
205int main(int argc, char **argv) {
206  sys::PrintStackTraceOnErrorSignal();
207  PrettyStackTraceProgram X(argc, argv);
208
209  // Enable debug stream buffering.
210  EnableDebugBuffering = true;
211
212  LLVMContext &Context = getGlobalContext();
213  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
214
215  // Initialize targets first, so that --version shows registered targets.
216  InitializeAllTargets();
217  InitializeAllAsmPrinters();
218  InitializeAllAsmParsers();
219
220  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
221
222  // Load the module to be compiled...
223  SMDiagnostic Err;
224  std::auto_ptr<Module> M;
225
226  M.reset(ParseIRFile(InputFilename, Err, Context));
227  if (M.get() == 0) {
228    Err.Print(argv[0], errs());
229    return 1;
230  }
231  Module &mod = *M.get();
232
233  // If we are supposed to override the target triple, do so now.
234  if (!TargetTriple.empty())
235    mod.setTargetTriple(TargetTriple);
236
237  Triple TheTriple(mod.getTargetTriple());
238  if (TheTriple.getTriple().empty())
239    TheTriple.setTriple(sys::getHostTriple());
240
241  // Allocate target machine.  First, check whether the user has explicitly
242  // specified an architecture to compile for. If so we have to look it up by
243  // name, because it might be a backend that has no mapping to a target triple.
244  const Target *TheTarget = 0;
245  if (!MArch.empty()) {
246    for (TargetRegistry::iterator it = TargetRegistry::begin(),
247           ie = TargetRegistry::end(); it != ie; ++it) {
248      if (MArch == it->getName()) {
249        TheTarget = &*it;
250        break;
251      }
252    }
253
254    if (!TheTarget) {
255      errs() << argv[0] << ": error: invalid target '" << MArch << "'.\n";
256      return 1;
257    }
258
259    // Adjust the triple to match (if known), otherwise stick with the
260    // module/host triple.
261    Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
262    if (Type != Triple::UnknownArch)
263      TheTriple.setArch(Type);
264  } else {
265    std::string Err;
266    TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Err);
267    if (TheTarget == 0) {
268      errs() << argv[0] << ": error auto-selecting target for module '"
269             << Err << "'.  Please use the -march option to explicitly "
270             << "pick a target.\n";
271      return 1;
272    }
273  }
274
275  // Package up features to be passed to target/subtarget
276  std::string FeaturesStr;
277  if (MCPU.size() || MAttrs.size()) {
278    SubtargetFeatures Features;
279    Features.setCPU(MCPU);
280    for (unsigned i = 0; i != MAttrs.size(); ++i)
281      Features.AddFeature(MAttrs[i]);
282    FeaturesStr = Features.getString();
283  }
284
285  std::auto_ptr<TargetMachine>
286    target(TheTarget->createTargetMachine(TheTriple.getTriple(), FeaturesStr));
287  assert(target.get() && "Could not allocate target machine!");
288  TargetMachine &Target = *target.get();
289
290  // Figure out where we are going to send the output...
291  formatted_raw_ostream *Out = GetOutputStream(TheTarget->getName(),
292                                               TheTriple.getOS(), argv[0]);
293  if (Out == 0) return 1;
294
295  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
296  switch (OptLevel) {
297  default:
298    errs() << argv[0] << ": invalid optimization level.\n";
299    return 1;
300  case ' ': break;
301  case '0': OLvl = CodeGenOpt::None; break;
302  case '1': OLvl = CodeGenOpt::Less; break;
303  case '2': OLvl = CodeGenOpt::Default; break;
304  case '3': OLvl = CodeGenOpt::Aggressive; break;
305  }
306
307  // Request that addPassesToEmitFile run the Verifier after running
308  // passes which modify the IR.
309#ifndef NDEBUG
310  bool DisableVerify = false;
311#else
312  bool DisableVerify = true;
313#endif
314
315  // Build up all of the passes that we want to do to the module.
316  PassManager PM;
317
318  // Add the target data from the target machine, if it exists, or the module.
319  if (const TargetData *TD = Target.getTargetData())
320    PM.add(new TargetData(*TD));
321  else
322    PM.add(new TargetData(&mod));
323
324  if (!NoVerify)
325    PM.add(createVerifierPass());
326
327  // Override default to generate verbose assembly.
328  Target.setAsmVerbosityDefault(true);
329
330  // Ask the target to add backend passes as necessary.
331  if (Target.addPassesToEmitFile(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
341  PM.run(mod);
342
343  // Delete the ostream if it's not a stdout stream
344  if (Out != &fouts()) delete Out;
345
346  return 0;
347}
348