llc.cpp revision 288943 
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
17#include "llvm/ADT/STLExtras.h"
18#include "llvm/ADT/Triple.h"
19#include "llvm/Analysis/TargetLibraryInfo.h"
20#include "llvm/CodeGen/CommandFlags.h"
21#include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
22#include "llvm/CodeGen/LinkAllCodegenComponents.h"
23#include "llvm/CodeGen/MIRParser/MIRParser.h"
24#include "llvm/IR/DataLayout.h"
25#include "llvm/IR/IRPrintingPasses.h"
26#include "llvm/IR/LLVMContext.h"
27#include "llvm/IR/LegacyPassManager.h"
28#include "llvm/IR/Module.h"
29#include "llvm/IR/Verifier.h"
30#include "llvm/IRReader/IRReader.h"
31#include "llvm/MC/SubtargetFeature.h"
32#include "llvm/Pass.h"
33#include "llvm/Support/CommandLine.h"
34#include "llvm/Support/Debug.h"
35#include "llvm/Support/FileSystem.h"
36#include "llvm/Support/FormattedStream.h"
37#include "llvm/Support/Host.h"
38#include "llvm/Support/ManagedStatic.h"
39#include "llvm/Support/PluginLoader.h"
40#include "llvm/Support/PrettyStackTrace.h"
41#include "llvm/Support/Signals.h"
42#include "llvm/Support/SourceMgr.h"
43#include "llvm/Support/TargetRegistry.h"
44#include "llvm/Support/TargetSelect.h"
45#include "llvm/Support/ToolOutputFile.h"
46#include "llvm/Target/TargetMachine.h"
47#include "llvm/Target/TargetSubtargetInfo.h"
48#include <memory>
49using namespace llvm;
50
51// General options for llc.  Other pass-specific options are specified
52// within the corresponding llc passes, and target-specific options
53// and back-end code generation options are specified with the target machine.
54//
55static cl::opt<std::string>
56InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
57
58static cl::opt<std::string>
59OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
60
61static cl::opt<unsigned>
62TimeCompilations("time-compilations", cl::Hidden, cl::init(1u),
63                 cl::value_desc("N"),
64                 cl::desc("Repeat compilation N times for timing"));
65
66static cl::opt<bool>
67NoIntegratedAssembler("no-integrated-as", cl::Hidden,
68                      cl::desc("Disable integrated assembler"));
69
70// Determine optimization level.
71static cl::opt<char>
72OptLevel("O",
73         cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
74                  "(default = '-O2')"),
75         cl::Prefix,
76         cl::ZeroOrMore,
77         cl::init(' '));
78
79static cl::opt<std::string>
80TargetTriple("mtriple", cl::desc("Override target triple for module"));
81
82static cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
83                              cl::desc("Do not verify input module"));
84
85static cl::opt<bool> DisableSimplifyLibCalls("disable-simplify-libcalls",
86                                             cl::desc("Disable simplify-libcalls"));
87
88static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden,
89                                    cl::desc("Show encoding in .s output"));
90
91static cl::opt<bool> EnableDwarfDirectory(
92    "enable-dwarf-directory", cl::Hidden,
93    cl::desc("Use .file directives with an explicit directory."));
94
95static cl::opt<bool> AsmVerbose("asm-verbose",
96                                cl::desc("Add comments to directives."),
97                                cl::init(true));
98
99static int compileModule(char **, LLVMContext &);
100
101static std::unique_ptr<tool_output_file>
102GetOutputStream(const char *TargetName, Triple::OSType OS,
103                const char *ProgName) {
104  // If we don't yet have an output filename, make one.
105  if (OutputFilename.empty()) {
106    if (InputFilename == "-")
107      OutputFilename = "-";
108    else {
109      // If InputFilename ends in .bc or .ll, remove it.
110      StringRef IFN = InputFilename;
111      if (IFN.endswith(".bc") || IFN.endswith(".ll"))
112        OutputFilename = IFN.drop_back(3);
113      else if (IFN.endswith(".mir"))
114        OutputFilename = IFN.drop_back(4);
115      else
116        OutputFilename = IFN;
117
118      switch (FileType) {
119      case TargetMachine::CGFT_AssemblyFile:
120        if (TargetName[0] == 'c') {
121          if (TargetName[1] == 0)
122            OutputFilename += ".cbe.c";
123          else if (TargetName[1] == 'p' && TargetName[2] == 'p')
124            OutputFilename += ".cpp";
125          else
126            OutputFilename += ".s";
127        } else
128          OutputFilename += ".s";
129        break;
130      case TargetMachine::CGFT_ObjectFile:
131        if (OS == Triple::Win32)
132          OutputFilename += ".obj";
133        else
134          OutputFilename += ".o";
135        break;
136      case TargetMachine::CGFT_Null:
137        OutputFilename += ".null";
138        break;
139      }
140    }
141  }
142
143  // Decide if we need "binary" output.
144  bool Binary = false;
145  switch (FileType) {
146  case TargetMachine::CGFT_AssemblyFile:
147    break;
148  case TargetMachine::CGFT_ObjectFile:
149  case TargetMachine::CGFT_Null:
150    Binary = true;
151    break;
152  }
153
154  // Open the file.
155  std::error_code EC;
156  sys::fs::OpenFlags OpenFlags = sys::fs::F_None;
157  if (!Binary)
158    OpenFlags |= sys::fs::F_Text;
159  auto FDOut = llvm::make_unique<tool_output_file>(OutputFilename, EC,
160                                                   OpenFlags);
161  if (EC) {
162    errs() << EC.message() << '\n';
163    return nullptr;
164  }
165
166  return FDOut;
167}
168
169// main - Entry point for the llc compiler.
170//
171int main(int argc, char **argv) {
172  sys::PrintStackTraceOnErrorSignal();
173  PrettyStackTraceProgram X(argc, argv);
174
175  // Enable debug stream buffering.
176  EnableDebugBuffering = true;
177
178  LLVMContext &Context = getGlobalContext();
179  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
180
181  // Initialize targets first, so that --version shows registered targets.
182  InitializeAllTargets();
183  InitializeAllTargetMCs();
184  InitializeAllAsmPrinters();
185  InitializeAllAsmParsers();
186
187  // Initialize codegen and IR passes used by llc so that the -print-after,
188  // -print-before, and -stop-after options work.
189  PassRegistry *Registry = PassRegistry::getPassRegistry();
190  initializeCore(*Registry);
191  initializeCodeGen(*Registry);
192  initializeLoopStrengthReducePass(*Registry);
193  initializeLowerIntrinsicsPass(*Registry);
194  initializeUnreachableBlockElimPass(*Registry);
195
196  // Register the target printer for --version.
197  cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
198
199  cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
200
201  // Compile the module TimeCompilations times to give better compile time
202  // metrics.
203  for (unsigned I = TimeCompilations; I; --I)
204    if (int RetVal = compileModule(argv, Context))
205      return RetVal;
206  return 0;
207}
208
209static int compileModule(char **argv, LLVMContext &Context) {
210  // Load the module to be compiled...
211  SMDiagnostic Err;
212  std::unique_ptr<Module> M;
213  std::unique_ptr<MIRParser> MIR;
214  Triple TheTriple;
215
216  bool SkipModule = MCPU == "help" ||
217                    (!MAttrs.empty() && MAttrs.front() == "help");
218
219  // If user just wants to list available options, skip module loading
220  if (!SkipModule) {
221    if (StringRef(InputFilename).endswith_lower(".mir")) {
222      MIR = createMIRParserFromFile(InputFilename, Err, Context);
223      if (MIR) {
224        M = MIR->parseLLVMModule();
225        assert(M && "parseLLVMModule should exit on failure");
226      }
227    } else
228      M = parseIRFile(InputFilename, Err, Context);
229    if (!M) {
230      Err.print(argv[0], errs());
231      return 1;
232    }
233
234    // Verify module immediately to catch problems before doInitialization() is
235    // called on any passes.
236    if (!NoVerify && verifyModule(*M, &errs())) {
237      errs() << argv[0] << ": " << InputFilename
238             << ": error: input module is broken!\n";
239      return 1;
240    }
241
242    // If we are supposed to override the target triple, do so now.
243    if (!TargetTriple.empty())
244      M->setTargetTriple(Triple::normalize(TargetTriple));
245    TheTriple = Triple(M->getTargetTriple());
246  } else {
247    TheTriple = Triple(Triple::normalize(TargetTriple));
248  }
249
250  if (TheTriple.getTriple().empty())
251    TheTriple.setTriple(sys::getDefaultTargetTriple());
252
253  // Get the target specific parser.
254  std::string Error;
255  const Target *TheTarget = TargetRegistry::lookupTarget(MArch, TheTriple,
256                                                         Error);
257  if (!TheTarget) {
258    errs() << argv[0] << ": " << Error;
259    return 1;
260  }
261
262  std::string CPUStr = getCPUStr(), FeaturesStr = getFeaturesStr();
263
264  CodeGenOpt::Level OLvl = CodeGenOpt::Default;
265  switch (OptLevel) {
266  default:
267    errs() << argv[0] << ": invalid optimization level.\n";
268    return 1;
269  case ' ': break;
270  case '0': OLvl = CodeGenOpt::None; break;
271  case '1': OLvl = CodeGenOpt::Less; break;
272  case '2': OLvl = CodeGenOpt::Default; break;
273  case '3': OLvl = CodeGenOpt::Aggressive; break;
274  }
275
276  TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
277  Options.DisableIntegratedAS = NoIntegratedAssembler;
278  Options.MCOptions.ShowMCEncoding = ShowMCEncoding;
279  Options.MCOptions.MCUseDwarfDirectory = EnableDwarfDirectory;
280  Options.MCOptions.AsmVerbose = AsmVerbose;
281
282  std::unique_ptr<TargetMachine> Target(
283      TheTarget->createTargetMachine(TheTriple.getTriple(), CPUStr, FeaturesStr,
284                                     Options, RelocModel, CMModel, OLvl));
285
286  assert(Target && "Could not allocate target machine!");
287
288  // If we don't have a module then just exit now. We do this down
289  // here since the CPU/Feature help is underneath the target machine
290  // creation.
291  if (SkipModule)
292    return 0;
293
294  assert(M && "Should have exited if we didn't have a module!");
295  if (FloatABIForCalls != FloatABI::Default)
296    Options.FloatABIType = FloatABIForCalls;
297
298  // Figure out where we are going to send the output.
299  std::unique_ptr<tool_output_file> Out =
300      GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]);
301  if (!Out) return 1;
302
303  // Build up all of the passes that we want to do to the module.
304  legacy::PassManager PM;
305
306  // Add an appropriate TargetLibraryInfo pass for the module's triple.
307  TargetLibraryInfoImpl TLII(Triple(M->getTargetTriple()));
308
309  // The -disable-simplify-libcalls flag actually disables all builtin optzns.
310  if (DisableSimplifyLibCalls)
311    TLII.disableAllFunctions();
312  PM.add(new TargetLibraryInfoWrapperPass(TLII));
313
314  // Add the target data from the target machine, if it exists, or the module.
315  if (const DataLayout *DL = Target->getDataLayout())
316    M->setDataLayout(*DL);
317
318  // Override function attributes based on CPUStr, FeaturesStr, and command line
319  // flags.
320  setFunctionAttributes(CPUStr, FeaturesStr, *M);
321
322  if (RelaxAll.getNumOccurrences() > 0 &&
323      FileType != TargetMachine::CGFT_ObjectFile)
324    errs() << argv[0]
325             << ": warning: ignoring -mc-relax-all because filetype != obj";
326
327  {
328    raw_pwrite_stream *OS = &Out->os();
329    std::unique_ptr<buffer_ostream> BOS;
330    if (FileType != TargetMachine::CGFT_AssemblyFile &&
331        !Out->os().supportsSeeking()) {
332      BOS = make_unique<buffer_ostream>(*OS);
333      OS = BOS.get();
334    }
335
336    AnalysisID StartBeforeID = nullptr;
337    AnalysisID StartAfterID = nullptr;
338    AnalysisID StopAfterID = nullptr;
339    const PassRegistry *PR = PassRegistry::getPassRegistry();
340    if (!RunPass.empty()) {
341      if (!StartAfter.empty() || !StopAfter.empty()) {
342        errs() << argv[0] << ": start-after and/or stop-after passes are "
343                             "redundant when run-pass is specified.\n";
344        return 1;
345      }
346      const PassInfo *PI = PR->getPassInfo(RunPass);
347      if (!PI) {
348        errs() << argv[0] << ": run-pass pass is not registered.\n";
349        return 1;
350      }
351      StopAfterID = StartBeforeID = PI->getTypeInfo();
352    } else {
353      if (!StartAfter.empty()) {
354        const PassInfo *PI = PR->getPassInfo(StartAfter);
355        if (!PI) {
356          errs() << argv[0] << ": start-after pass is not registered.\n";
357          return 1;
358        }
359        StartAfterID = PI->getTypeInfo();
360      }
361      if (!StopAfter.empty()) {
362        const PassInfo *PI = PR->getPassInfo(StopAfter);
363        if (!PI) {
364          errs() << argv[0] << ": stop-after pass is not registered.\n";
365          return 1;
366        }
367        StopAfterID = PI->getTypeInfo();
368      }
369    }
370
371    // Ask the target to add backend passes as necessary.
372    if (Target->addPassesToEmitFile(PM, *OS, FileType, NoVerify, StartBeforeID,
373                                    StartAfterID, StopAfterID, MIR.get())) {
374      errs() << argv[0] << ": target does not support generation of this"
375             << " file type!\n";
376      return 1;
377    }
378
379    // Before executing passes, print the final values of the LLVM options.
380    cl::PrintOptionValues();
381
382    PM.run(*M);
383  }
384
385  // Declare success.
386  Out->keep();
387
388  return 0;
389}
390