llc.cpp revision 2388a588bdf32610e18a66c0c6ef248087fd1cdc 
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/Bitcode/ReaderWriter.h"
17#include "llvm/CodeGen/FileWriters.h"
18#include "llvm/CodeGen/LinkAllCodegenComponents.h"
19#include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
20#include "llvm/Target/SubtargetFeature.h"
21#include "llvm/Target/TargetData.h"
22#include "llvm/Target/TargetMachine.h"
23#include "llvm/Target/TargetMachineRegistry.h"
24#include "llvm/Transforms/Scalar.h"
25#include "llvm/Module.h"
26#include "llvm/ModuleProvider.h"
27#include "llvm/PassManager.h"
28#include "llvm/Pass.h"
29#include "llvm/Support/CommandLine.h"
30#include "llvm/Support/FileUtilities.h"
31#include "llvm/Support/ManagedStatic.h"
32#include "llvm/Support/MemoryBuffer.h"
33#include "llvm/Support/PluginLoader.h"
34#include "llvm/Support/RegistryParser.h"
35#include "llvm/Support/raw_ostream.h"
36#include "llvm/Analysis/Verifier.h"
37#include "llvm/System/Signals.h"
38#include "llvm/Config/config.h"
39#include "llvm/LinkAllVMCore.h"
40#include <fstream>
41#include <iostream>
42#include <memory>
43using namespace llvm;
44
45// General options for llc.  Other pass-specific options are specified
46// within the corresponding llc passes, and target-specific options
47// and back-end code generation options are specified with the target machine.
48//
49static cl::opt<std::string>
50InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
51
52static cl::opt<std::string>
53OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
54
55static cl::opt<bool> Force("f", cl::desc("Overwrite output files"));
56
57static cl::opt<bool> Fast("fast",
58      cl::desc("Generate code quickly, potentially sacrificing code quality"));
59
60static cl::opt<std::string>
61TargetTriple("mtriple", cl::desc("Override target triple for module"));
62
63static cl::opt<const TargetMachineRegistry::entry*, false,
64               RegistryParser<TargetMachine> >
65MArch("march", cl::desc("Architecture to generate code for:"));
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::AssemblyFile),
81  cl::desc("Choose a file type (not all types are supported by all targets):"),
82  cl::values(
83       clEnumValN(TargetMachine::AssemblyFile, "asm",
84                  "Emit an assembly ('.s') file"),
85       clEnumValN(TargetMachine::ObjectFile, "obj",
86                  "Emit a native object ('.o') file [experimental]"),
87       clEnumValN(TargetMachine::DynamicLibrary, "dynlib",
88                  "Emit a native dynamic library ('.so') file"
89                  " [experimental]"),
90       clEnumValEnd));
91
92cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
93                       cl::desc("Do not verify input module"));
94
95
96// GetFileNameRoot - Helper function to get the basename of a filename.
97static inline std::string
98GetFileNameRoot(const std::string &InputFilename) {
99  std::string IFN = InputFilename;
100  std::string outputFilename;
101  int Len = IFN.length();
102  if ((Len > 2) &&
103      IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c') {
104    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
105  } else {
106    outputFilename = IFN;
107  }
108  return outputFilename;
109}
110
111static raw_ostream *GetOutputStream(const char *ProgName) {
112  if (OutputFilename != "") {
113    if (OutputFilename == "-")
114      return &outs();
115
116    // Specified an output filename?
117    if (!Force && std::ifstream(OutputFilename.c_str())) {
118      // If force is not specified, make sure not to overwrite a file!
119      std::cerr << ProgName << ": error opening '" << OutputFilename
120                << "': file exists!\n"
121                << "Use -f command line argument to force output\n";
122      return 0;
123    }
124    // Make sure that the Out file gets unlinked from the disk if we get a
125    // SIGINT
126    sys::RemoveFileOnSignal(sys::Path(OutputFilename));
127
128    std::string error;
129    raw_ostream *Out = new raw_fd_ostream(OutputFilename.c_str(), true, error);
130    if (!error.empty()) {
131      std::cerr << error << '\n';
132      delete Out;
133      return 0;
134    }
135
136    return Out;
137  }
138
139  if (InputFilename == "-") {
140    OutputFilename = "-";
141    return &outs();
142  }
143
144  OutputFilename = GetFileNameRoot(InputFilename);
145
146  bool Binary = false;
147  switch (FileType) {
148  case TargetMachine::AssemblyFile:
149    if (MArch->Name[0] == 'c') {
150      if (MArch->Name[1] == 0)
151        OutputFilename += ".cbe.c";
152      else if (MArch->Name[1] == 'p' && MArch->Name[2] == 'p')
153        OutputFilename += ".cpp";
154      else
155        OutputFilename += ".s";
156    } else
157      OutputFilename += ".s";
158    break;
159  case TargetMachine::ObjectFile:
160    OutputFilename += ".o";
161    Binary = true;
162    break;
163  case TargetMachine::DynamicLibrary:
164    OutputFilename += LTDL_SHLIB_EXT;
165    Binary = true;
166    break;
167  }
168
169  if (!Force && std::ifstream(OutputFilename.c_str())) {
170    // If force is not specified, make sure not to overwrite a file!
171    std::cerr << ProgName << ": error opening '" << OutputFilename
172                          << "': file exists!\n"
173                          << "Use -f command line argument to force output\n";
174    return 0;
175  }
176
177  // Make sure that the Out file gets unlinked from the disk if we get a
178  // SIGINT
179  sys::RemoveFileOnSignal(sys::Path(OutputFilename));
180
181  std::string error;
182  raw_ostream *Out = new raw_fd_ostream(OutputFilename.c_str(), Binary, error);
183  if (!error.empty()) {
184    std::cerr << error << '\n';
185    delete Out;
186    return 0;
187  }
188
189  return Out;
190}
191
192// main - Entry point for the llc compiler.
193//
194int main(int argc, char **argv) {
195  llvm_shutdown_obj X;  // Call llvm_shutdown() on exit.
196  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
197  sys::PrintStackTraceOnErrorSignal();
198
199  // Load the module to be compiled...
200  std::string ErrorMessage;
201  std::auto_ptr<Module> M;
202
203  std::auto_ptr<MemoryBuffer> Buffer(
204                   MemoryBuffer::getFileOrSTDIN(InputFilename, &ErrorMessage));
205  if (Buffer.get())
206    M.reset(ParseBitcodeFile(Buffer.get(), &ErrorMessage));
207  if (M.get() == 0) {
208    std::cerr << argv[0] << ": bitcode didn't read correctly.\n";
209    std::cerr << "Reason: " << ErrorMessage << "\n";
210    return 1;
211  }
212  Module &mod = *M.get();
213
214  // If we are supposed to override the target triple, do so now.
215  if (!TargetTriple.empty())
216    mod.setTargetTriple(TargetTriple);
217
218  // Allocate target machine.  First, check whether the user has
219  // explicitly specified an architecture to compile for.
220  if (MArch == 0) {
221    std::string Err;
222    MArch = TargetMachineRegistry::getClosestStaticTargetForModule(mod, Err);
223    if (MArch == 0) {
224      std::cerr << argv[0] << ": error auto-selecting target for module '"
225                << Err << "'.  Please use the -march option to explicitly "
226                << "pick a target.\n";
227      return 1;
228    }
229  }
230
231  // Package up features to be passed to target/subtarget
232  std::string FeaturesStr;
233  if (MCPU.size() || MAttrs.size()) {
234    SubtargetFeatures Features;
235    Features.setCPU(MCPU);
236    for (unsigned i = 0; i != MAttrs.size(); ++i)
237      Features.AddFeature(MAttrs[i]);
238    FeaturesStr = Features.getString();
239  }
240
241  std::auto_ptr<TargetMachine> target(MArch->CtorFn(mod, FeaturesStr));
242  assert(target.get() && "Could not allocate target machine!");
243  TargetMachine &Target = *target.get();
244
245  // Figure out where we are going to send the output...
246  raw_ostream *Out = GetOutputStream(argv[0]);
247  if (Out == 0) return 1;
248
249  // If this target requires addPassesToEmitWholeFile, do it now.  This is
250  // used by strange things like the C backend.
251  if (Target.WantsWholeFile()) {
252    PassManager PM;
253    PM.add(new TargetData(*Target.getTargetData()));
254    if (!NoVerify)
255      PM.add(createVerifierPass());
256
257    // Ask the target to add backend passes as necessary.
258    if (Target.addPassesToEmitWholeFile(PM, *Out, FileType, Fast)) {
259      std::cerr << argv[0] << ": target does not support generation of this"
260                << " file type!\n";
261      if (Out != &outs()) delete Out;
262      // And the Out file is empty and useless, so remove it now.
263      sys::Path(OutputFilename).eraseFromDisk();
264      return 1;
265    }
266    PM.run(mod);
267  } else {
268    // Build up all of the passes that we want to do to the module.
269    ExistingModuleProvider Provider(M.release());
270    FunctionPassManager Passes(&Provider);
271    Passes.add(new TargetData(*Target.getTargetData()));
272
273#ifndef NDEBUG
274    if (!NoVerify)
275      Passes.add(createVerifierPass());
276#endif
277
278    // Ask the target to add backend passes as necessary.
279    MachineCodeEmitter *MCE = 0;
280
281    switch (Target.addPassesToEmitFile(Passes, *Out, FileType, Fast)) {
282    default:
283      assert(0 && "Invalid file model!");
284      return 1;
285    case FileModel::Error:
286      std::cerr << argv[0] << ": target does not support generation of this"
287                << " file type!\n";
288      if (Out != &outs()) delete Out;
289      // And the Out file is empty and useless, so remove it now.
290      sys::Path(OutputFilename).eraseFromDisk();
291      return 1;
292    case FileModel::AsmFile:
293      break;
294    case FileModel::MachOFile:
295      MCE = AddMachOWriter(Passes, *Out, Target);
296      break;
297    case FileModel::ElfFile:
298      MCE = AddELFWriter(Passes, *Out, Target);
299      break;
300    }
301
302    if (Target.addPassesToEmitFileFinish(Passes, MCE, Fast)) {
303      std::cerr << argv[0] << ": target does not support generation of this"
304                << " file type!\n";
305      if (Out != &outs()) delete Out;
306      // And the Out file is empty and useless, so remove it now.
307      sys::Path(OutputFilename).eraseFromDisk();
308      return 1;
309    }
310
311    Passes.doInitialization();
312
313    // Run our queue of passes all at once now, efficiently.
314    // TODO: this could lazily stream functions out of the module.
315    for (Module::iterator I = mod.begin(), E = mod.end(); I != E; ++I)
316      if (!I->isDeclaration())
317        Passes.run(*I);
318
319    Passes.doFinalization();
320  }
321
322  // Delete the ostream if it's not a stdout stream
323  if (Out != &outs()) delete Out;
324
325  return 0;
326}
327