llc.cpp revision c9234c583573cfc0b19a94ecd766e2521e75e91c 
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
79static cl::opt<bool>
80RelaxAll("mc-relax-all",
81  cl::desc("When used with filetype=obj, "
82           "relax all fixups in the emitted object file"));
83
84cl::opt<TargetMachine::CodeGenFileType>
85FileType("filetype", cl::init(TargetMachine::CGFT_AssemblyFile),
86  cl::desc("Choose a file type (not all types are supported by all targets):"),
87  cl::values(
88       clEnumValN(TargetMachine::CGFT_AssemblyFile, "asm",
89                  "Emit an assembly ('.s') file"),
90       clEnumValN(TargetMachine::CGFT_ObjectFile, "obj",
91                  "Emit a native object ('.o') file [experimental]"),
92       clEnumValN(TargetMachine::CGFT_Null, "null",
93                  "Emit nothing, for performance testing"),
94       clEnumValEnd));
95
96cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
97                       cl::desc("Do not verify input module"));
98
99
100static cl::opt<bool>
101DisableRedZone("disable-red-zone",
102  cl::desc("Do not emit code that uses the red zone."),
103  cl::init(false));
104
105static cl::opt<bool>
106NoImplicitFloats("no-implicit-float",
107  cl::desc("Don't generate implicit floating point instructions (x86-only)"),
108  cl::init(false));
109
110// GetFileNameRoot - Helper function to get the basename of a filename.
111static inline std::string
112GetFileNameRoot(const std::string &InputFilename) {
113  std::string IFN = InputFilename;
114  std::string outputFilename;
115  int Len = IFN.length();
116  if ((Len > 2) &&
117      IFN[Len-3] == '.' &&
118      ((IFN[Len-2] == 'b' && IFN[Len-1] == 'c') ||
119       (IFN[Len-2] == 'l' && IFN[Len-1] == 'l'))) {
120    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
121  } else {
122    outputFilename = IFN;
123  }
124  return outputFilename;
125}
126
127static formatted_raw_ostream *GetOutputStream(const char *TargetName,
128                                              Triple::OSType OS,
129                                              const char *ProgName) {
130  if (OutputFilename != "") {
131    if (OutputFilename == "-")
132      return new formatted_raw_ostream(outs(),
133                                       formatted_raw_ostream::PRESERVE_STREAM);
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 new formatted_raw_ostream(outs(),
157                                     formatted_raw_ostream::PRESERVE_STREAM);
158  }
159
160  OutputFilename = GetFileNameRoot(InputFilename);
161
162  bool Binary = false;
163  switch (FileType) {
164  default: assert(0 && "Unknown file type");
165  case TargetMachine::CGFT_AssemblyFile:
166    if (TargetName[0] == 'c') {
167      if (TargetName[1] == 0)
168        OutputFilename += ".cbe.c";
169      else if (TargetName[1] == 'p' && TargetName[2] == 'p')
170        OutputFilename += ".cpp";
171      else
172        OutputFilename += ".s";
173    } else
174      OutputFilename += ".s";
175    break;
176  case TargetMachine::CGFT_ObjectFile:
177    if (OS == Triple::Win32)
178      OutputFilename += ".obj";
179    else
180      OutputFilename += ".o";
181    Binary = true;
182    break;
183  case TargetMachine::CGFT_Null:
184    OutputFilename += ".null";
185    Binary = true;
186    break;
187  }
188
189  // Make sure that the Out file gets unlinked from the disk if we get a
190  // SIGINT
191  sys::RemoveFileOnSignal(sys::Path(OutputFilename));
192
193  std::string error;
194  unsigned OpenFlags = 0;
195  if (Binary) OpenFlags |= raw_fd_ostream::F_Binary;
196  raw_fd_ostream *FDOut = new raw_fd_ostream(OutputFilename.c_str(), error,
197                                             OpenFlags);
198  if (!error.empty()) {
199    errs() << error << '\n';
200    delete FDOut;
201    return 0;
202  }
203
204  formatted_raw_ostream *Out =
205    new formatted_raw_ostream(*FDOut, formatted_raw_ostream::DELETE_STREAM);
206
207  return Out;
208}
209
210// main - Entry point for the llc compiler.
211//
212int main(int argc, char **argv) {
213  sys::PrintStackTraceOnErrorSignal();
214  PrettyStackTraceProgram X(argc, argv);
215
216  // Enable debug stream buffering.
217  EnableDebugBuffering = true;
218
219  LLVMContext &Context = getGlobalContext();
220  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
221
222  // Initialize targets first, so that --version shows registered targets.
223  InitializeAllTargets();
224  InitializeAllAsmPrinters();
225  InitializeAllAsmParsers();
226
227  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
228
229  // Load the module to be compiled...
230  SMDiagnostic Err;
231  std::auto_ptr<Module> M;
232
233  M.reset(ParseIRFile(InputFilename, Err, Context));
234  if (M.get() == 0) {
235    Err.Print(argv[0], errs());
236    return 1;
237  }
238  Module &mod = *M.get();
239
240  // If we are supposed to override the target triple, do so now.
241  if (!TargetTriple.empty())
242    mod.setTargetTriple(TargetTriple);
243
244  Triple TheTriple(mod.getTargetTriple());
245  if (TheTriple.getTriple().empty())
246    TheTriple.setTriple(sys::getHostTriple());
247
248  // Allocate target machine.  First, check whether the user has explicitly
249  // specified an architecture to compile for. If so we have to look it up by
250  // name, because it might be a backend that has no mapping to a target triple.
251  const Target *TheTarget = 0;
252  if (!MArch.empty()) {
253    for (TargetRegistry::iterator it = TargetRegistry::begin(),
254           ie = TargetRegistry::end(); it != ie; ++it) {
255      if (MArch == it->getName()) {
256        TheTarget = &*it;
257        break;
258      }
259    }
260
261    if (!TheTarget) {
262      errs() << argv[0] << ": error: invalid target '" << MArch << "'.\n";
263      return 1;
264    }
265
266    // Adjust the triple to match (if known), otherwise stick with the
267    // module/host triple.
268    Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
269    if (Type != Triple::UnknownArch)
270      TheTriple.setArch(Type);
271  } else {
272    std::string Err;
273    TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Err);
274    if (TheTarget == 0) {
275      errs() << argv[0] << ": error auto-selecting target for module '"
276             << Err << "'.  Please use the -march option to explicitly "
277             << "pick a target.\n";
278      return 1;
279    }
280  }
281
282  // Package up features to be passed to target/subtarget
283  std::string FeaturesStr;
284  if (MCPU.size() || MAttrs.size()) {
285    SubtargetFeatures Features;
286    Features.setCPU(MCPU);
287    for (unsigned i = 0; i != MAttrs.size(); ++i)
288      Features.AddFeature(MAttrs[i]);
289    FeaturesStr = Features.getString();
290  }
291
292  std::auto_ptr<TargetMachine>
293    target(TheTarget->createTargetMachine(TheTriple.getTriple(), FeaturesStr));
294  assert(target.get() && "Could not allocate target machine!");
295  TargetMachine &Target = *target.get();
296
297  // Figure out where we are going to send the output...
298  formatted_raw_ostream *Out = GetOutputStream(TheTarget->getName(),
299                                               TheTriple.getOS(), argv[0]);
300  if (Out == 0) return 1;
301
302  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
303  switch (OptLevel) {
304  default:
305    errs() << argv[0] << ": invalid optimization level.\n";
306    return 1;
307  case ' ': break;
308  case '0': OLvl = CodeGenOpt::None; break;
309  case '1': OLvl = CodeGenOpt::Less; break;
310  case '2': OLvl = CodeGenOpt::Default; break;
311  case '3': OLvl = CodeGenOpt::Aggressive; break;
312  }
313
314  // Request that addPassesToEmitFile run the Verifier after running
315  // passes which modify the IR.
316#ifndef NDEBUG
317  bool DisableVerify = false;
318#else
319  bool DisableVerify = true;
320#endif
321
322  // Build up all of the passes that we want to do to the module.
323  PassManager PM;
324
325  // Add the target data from the target machine, if it exists, or the module.
326  if (const TargetData *TD = Target.getTargetData())
327    PM.add(new TargetData(*TD));
328  else
329    PM.add(new TargetData(&mod));
330
331  if (!NoVerify)
332    PM.add(createVerifierPass());
333
334  // Override default to generate verbose assembly.
335  Target.setAsmVerbosityDefault(true);
336
337  if (RelaxAll) {
338    if (FileType != TargetMachine::CGFT_ObjectFile)
339      errs() << argv[0]
340             << ": warning: ignoring -mc-relax-all because filetype != obj";
341    else
342      Target.setMCRelaxAll(true);
343  }
344
345  // Ask the target to add backend passes as necessary.
346  if (Target.addPassesToEmitFile(PM, *Out, FileType, OLvl,
347                                 DisableVerify)) {
348    errs() << argv[0] << ": target does not support generation of this"
349           << " file type!\n";
350    delete Out;
351    // And the Out file is empty and useless, so remove it now.
352    sys::Path(OutputFilename).eraseFromDisk();
353    return 1;
354  }
355
356  PM.run(mod);
357
358  // Delete the ostream.
359  delete Out;
360
361  return 0;
362}
363