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/CodeGen/MachineFunctionPass.h"
25 #include "llvm/CodeGen/MachineModuleInfo.h"
26 #include "llvm/CodeGen/TargetPassConfig.h"
27 #include "llvm/IR/DataLayout.h"
28 #include "llvm/IR/DiagnosticInfo.h"
29 #include "llvm/IR/DiagnosticPrinter.h"
30 #include "llvm/IR/IRPrintingPasses.h"
31 #include "llvm/IR/LLVMContext.h"
32 #include "llvm/IR/LegacyPassManager.h"
33 #include "llvm/IR/Module.h"
34 #include "llvm/IR/Verifier.h"
35 #include "llvm/IRReader/IRReader.h"
36 #include "llvm/MC/SubtargetFeature.h"
37 #include "llvm/Pass.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Support/FileSystem.h"
41 #include "llvm/Support/FormattedStream.h"
42 #include "llvm/Support/Host.h"
43 #include "llvm/Support/ManagedStatic.h"
44 #include "llvm/Support/PluginLoader.h"
45 #include "llvm/Support/PrettyStackTrace.h"
46 #include "llvm/Support/Signals.h"
47 #include "llvm/Support/SourceMgr.h"
48 #include "llvm/Support/TargetRegistry.h"
49 #include "llvm/Support/TargetSelect.h"
50 #include "llvm/Support/ToolOutputFile.h"
51 #include "llvm/Target/TargetMachine.h"
52 #include "llvm/Target/TargetSubtargetInfo.h"
53 #include "llvm/Transforms/Utils/Cloning.h"
54 #include <memory>
55 using namespace llvm;
56
57 // General options for llc. Other pass-specific options are specified
58 // within the corresponding llc passes, and target-specific options
59 // and back-end code generation options are specified with the target machine.
60 //
61 static cl::opt<std::string>
62 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
63
64 static cl::opt<std::string>
65 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
66
67 static cl::opt<unsigned>
68 TimeCompilations("time-compilations", cl::Hidden, cl::init(1u),
69 cl::value_desc("N"),
70 cl::desc("Repeat compilation N times for timing"));
71
72 static cl::opt<bool>
73 NoIntegratedAssembler("no-integrated-as", cl::Hidden,
74 cl::desc("Disable integrated assembler"));
75
76 static cl::opt<bool>
77 PreserveComments("preserve-as-comments", cl::Hidden,
78 cl::desc("Preserve Comments in outputted assembly"),
79 cl::init(true));
80
81 // Determine optimization level.
82 static cl::opt<char>
83 OptLevel("O",
84 cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
85 "(default = '-O2')"),
86 cl::Prefix,
87 cl::ZeroOrMore,
88 cl::init(' '));
89
90 static cl::opt<std::string>
91 TargetTriple("mtriple", cl::desc("Override target triple for module"));
92
93 static cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
94 cl::desc("Do not verify input module"));
95
96 static cl::opt<bool> DisableSimplifyLibCalls("disable-simplify-libcalls",
97 cl::desc("Disable simplify-libcalls"));
98
99 static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden,
100 cl::desc("Show encoding in .s output"));
101
102 static cl::opt<bool> EnableDwarfDirectory(
103 "enable-dwarf-directory", cl::Hidden,
104 cl::desc("Use .file directives with an explicit directory."));
105
106 static cl::opt<bool> AsmVerbose("asm-verbose",
107 cl::desc("Add comments to directives."),
108 cl::init(true));
109
110 static cl::opt<bool>
111 CompileTwice("compile-twice", cl::Hidden,
112 cl::desc("Run everything twice, re-using the same pass "
113 "manager and verify the result is the same."),
114 cl::init(false));
115
116 static cl::opt<bool> DiscardValueNames(
117 "discard-value-names",
118 cl::desc("Discard names from Value (other than GlobalValue)."),
119 cl::init(false), cl::Hidden);
120
121 namespace {
122 static ManagedStatic<std::vector<std::string>> RunPassNames;
123
124 struct RunPassOption {
operator =__anone0092ce70111::RunPassOption125 void operator=(const std::string &Val) const {
126 if (Val.empty())
127 return;
128 SmallVector<StringRef, 8> PassNames;
129 StringRef(Val).split(PassNames, ',', -1, false);
130 for (auto PassName : PassNames)
131 RunPassNames->push_back(PassName);
132 }
133 };
134 }
135
136 static RunPassOption RunPassOpt;
137
138 static cl::opt<RunPassOption, true, cl::parser<std::string>> RunPass(
139 "run-pass",
140 cl::desc("Run compiler only for specified passes (comma separated list)"),
141 cl::value_desc("pass-name"), cl::ZeroOrMore, cl::location(RunPassOpt));
142
143 static int compileModule(char **, LLVMContext &);
144
145 static std::unique_ptr<tool_output_file>
GetOutputStream(const char * TargetName,Triple::OSType OS,const char * ProgName)146 GetOutputStream(const char *TargetName, Triple::OSType OS,
147 const char *ProgName) {
148 // If we don't yet have an output filename, make one.
149 if (OutputFilename.empty()) {
150 if (InputFilename == "-")
151 OutputFilename = "-";
152 else {
153 // If InputFilename ends in .bc or .ll, remove it.
154 StringRef IFN = InputFilename;
155 if (IFN.endswith(".bc") || IFN.endswith(".ll"))
156 OutputFilename = IFN.drop_back(3);
157 else if (IFN.endswith(".mir"))
158 OutputFilename = IFN.drop_back(4);
159 else
160 OutputFilename = IFN;
161
162 switch (FileType) {
163 case TargetMachine::CGFT_AssemblyFile:
164 if (TargetName[0] == 'c') {
165 if (TargetName[1] == 0)
166 OutputFilename += ".cbe.c";
167 else if (TargetName[1] == 'p' && TargetName[2] == 'p')
168 OutputFilename += ".cpp";
169 else
170 OutputFilename += ".s";
171 } else
172 OutputFilename += ".s";
173 break;
174 case TargetMachine::CGFT_ObjectFile:
175 if (OS == Triple::Win32)
176 OutputFilename += ".obj";
177 else
178 OutputFilename += ".o";
179 break;
180 case TargetMachine::CGFT_Null:
181 OutputFilename += ".null";
182 break;
183 }
184 }
185 }
186
187 // Decide if we need "binary" output.
188 bool Binary = false;
189 switch (FileType) {
190 case TargetMachine::CGFT_AssemblyFile:
191 break;
192 case TargetMachine::CGFT_ObjectFile:
193 case TargetMachine::CGFT_Null:
194 Binary = true;
195 break;
196 }
197
198 // Open the file.
199 std::error_code EC;
200 sys::fs::OpenFlags OpenFlags = sys::fs::F_None;
201 if (!Binary)
202 OpenFlags |= sys::fs::F_Text;
203 auto FDOut = llvm::make_unique<tool_output_file>(OutputFilename, EC,
204 OpenFlags);
205 if (EC) {
206 errs() << EC.message() << '\n';
207 return nullptr;
208 }
209
210 return FDOut;
211 }
212
DiagnosticHandler(const DiagnosticInfo & DI,void * Context)213 static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context) {
214 bool *HasError = static_cast<bool *>(Context);
215 if (DI.getSeverity() == DS_Error)
216 *HasError = true;
217
218 DiagnosticPrinterRawOStream DP(errs());
219 errs() << LLVMContext::getDiagnosticMessagePrefix(DI.getSeverity()) << ": ";
220 DI.print(DP);
221 errs() << "\n";
222 }
223
224 // main - Entry point for the llc compiler.
225 //
main(int argc,char ** argv)226 int main(int argc, char **argv) {
227 sys::PrintStackTraceOnErrorSignal(argv[0]);
228 PrettyStackTraceProgram X(argc, argv);
229
230 // Enable debug stream buffering.
231 EnableDebugBuffering = true;
232
233 LLVMContext Context;
234 llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
235
236 // Initialize targets first, so that --version shows registered targets.
237 InitializeAllTargets();
238 InitializeAllTargetMCs();
239 InitializeAllAsmPrinters();
240 InitializeAllAsmParsers();
241
242 // Initialize codegen and IR passes used by llc so that the -print-after,
243 // -print-before, and -stop-after options work.
244 PassRegistry *Registry = PassRegistry::getPassRegistry();
245 initializeCore(*Registry);
246 initializeCodeGen(*Registry);
247 initializeLoopStrengthReducePass(*Registry);
248 initializeLowerIntrinsicsPass(*Registry);
249 initializeUnreachableBlockElimLegacyPassPass(*Registry);
250
251 // Register the target printer for --version.
252 cl::AddExtraVersionPrinter(TargetRegistry::printRegisteredTargetsForVersion);
253
254 cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
255
256 Context.setDiscardValueNames(DiscardValueNames);
257
258 // Set a diagnostic handler that doesn't exit on the first error
259 bool HasError = false;
260 Context.setDiagnosticHandler(DiagnosticHandler, &HasError);
261
262 // Compile the module TimeCompilations times to give better compile time
263 // metrics.
264 for (unsigned I = TimeCompilations; I; --I)
265 if (int RetVal = compileModule(argv, Context))
266 return RetVal;
267 return 0;
268 }
269
compileModule(char ** argv,LLVMContext & Context)270 static int compileModule(char **argv, LLVMContext &Context) {
271 // Load the module to be compiled...
272 SMDiagnostic Err;
273 std::unique_ptr<Module> M;
274 std::unique_ptr<MIRParser> MIR;
275 Triple TheTriple;
276
277 bool SkipModule = MCPU == "help" ||
278 (!MAttrs.empty() && MAttrs.front() == "help");
279
280 // If user just wants to list available options, skip module loading
281 if (!SkipModule) {
282 if (StringRef(InputFilename).endswith_lower(".mir")) {
283 MIR = createMIRParserFromFile(InputFilename, Err, Context);
284 if (MIR)
285 M = MIR->parseLLVMModule();
286 } else
287 M = parseIRFile(InputFilename, Err, Context);
288 if (!M) {
289 Err.print(argv[0], errs());
290 return 1;
291 }
292
293 // Verify module immediately to catch problems before doInitialization() is
294 // called on any passes.
295 if (!NoVerify && verifyModule(*M, &errs())) {
296 errs() << argv[0] << ": " << InputFilename
297 << ": error: input module is broken!\n";
298 return 1;
299 }
300
301 // If we are supposed to override the target triple, do so now.
302 if (!TargetTriple.empty())
303 M->setTargetTriple(Triple::normalize(TargetTriple));
304 TheTriple = Triple(M->getTargetTriple());
305 } else {
306 TheTriple = Triple(Triple::normalize(TargetTriple));
307 }
308
309 if (TheTriple.getTriple().empty())
310 TheTriple.setTriple(sys::getDefaultTargetTriple());
311
312 // Get the target specific parser.
313 std::string Error;
314 const Target *TheTarget = TargetRegistry::lookupTarget(MArch, TheTriple,
315 Error);
316 if (!TheTarget) {
317 errs() << argv[0] << ": " << Error;
318 return 1;
319 }
320
321 std::string CPUStr = getCPUStr(), FeaturesStr = getFeaturesStr();
322
323 CodeGenOpt::Level OLvl = CodeGenOpt::Default;
324 switch (OptLevel) {
325 default:
326 errs() << argv[0] << ": invalid optimization level.\n";
327 return 1;
328 case ' ': break;
329 case '0': OLvl = CodeGenOpt::None; break;
330 case '1': OLvl = CodeGenOpt::Less; break;
331 case '2': OLvl = CodeGenOpt::Default; break;
332 case '3': OLvl = CodeGenOpt::Aggressive; break;
333 }
334
335 TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
336 Options.DisableIntegratedAS = NoIntegratedAssembler;
337 Options.MCOptions.ShowMCEncoding = ShowMCEncoding;
338 Options.MCOptions.MCUseDwarfDirectory = EnableDwarfDirectory;
339 Options.MCOptions.AsmVerbose = AsmVerbose;
340 Options.MCOptions.PreserveAsmComments = PreserveComments;
341
342 std::unique_ptr<TargetMachine> Target(
343 TheTarget->createTargetMachine(TheTriple.getTriple(), CPUStr, FeaturesStr,
344 Options, getRelocModel(), CMModel, OLvl));
345
346 assert(Target && "Could not allocate target machine!");
347
348 // If we don't have a module then just exit now. We do this down
349 // here since the CPU/Feature help is underneath the target machine
350 // creation.
351 if (SkipModule)
352 return 0;
353
354 assert(M && "Should have exited if we didn't have a module!");
355 if (FloatABIForCalls != FloatABI::Default)
356 Options.FloatABIType = FloatABIForCalls;
357
358 // Figure out where we are going to send the output.
359 std::unique_ptr<tool_output_file> Out =
360 GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]);
361 if (!Out) return 1;
362
363 // Build up all of the passes that we want to do to the module.
364 legacy::PassManager PM;
365
366 // Add an appropriate TargetLibraryInfo pass for the module's triple.
367 TargetLibraryInfoImpl TLII(Triple(M->getTargetTriple()));
368
369 // The -disable-simplify-libcalls flag actually disables all builtin optzns.
370 if (DisableSimplifyLibCalls)
371 TLII.disableAllFunctions();
372 PM.add(new TargetLibraryInfoWrapperPass(TLII));
373
374 // Add the target data from the target machine, if it exists, or the module.
375 M->setDataLayout(Target->createDataLayout());
376
377 // Override function attributes based on CPUStr, FeaturesStr, and command line
378 // flags.
379 setFunctionAttributes(CPUStr, FeaturesStr, *M);
380
381 if (RelaxAll.getNumOccurrences() > 0 &&
382 FileType != TargetMachine::CGFT_ObjectFile)
383 errs() << argv[0]
384 << ": warning: ignoring -mc-relax-all because filetype != obj";
385
386 {
387 raw_pwrite_stream *OS = &Out->os();
388
389 // Manually do the buffering rather than using buffer_ostream,
390 // so we can memcmp the contents in CompileTwice mode
391 SmallVector<char, 0> Buffer;
392 std::unique_ptr<raw_svector_ostream> BOS;
393 if ((FileType != TargetMachine::CGFT_AssemblyFile &&
394 !Out->os().supportsSeeking()) ||
395 CompileTwice) {
396 BOS = make_unique<raw_svector_ostream>(Buffer);
397 OS = BOS.get();
398 }
399
400 AnalysisID StartBeforeID = nullptr;
401 AnalysisID StartAfterID = nullptr;
402 AnalysisID StopAfterID = nullptr;
403 const PassRegistry *PR = PassRegistry::getPassRegistry();
404 if (!RunPassNames->empty()) {
405 if (!StartAfter.empty() || !StopAfter.empty()) {
406 errs() << argv[0] << ": start-after and/or stop-after passes are "
407 "redundant when run-pass is specified.\n";
408 return 1;
409 }
410 if (!MIR) {
411 errs() << argv[0] << ": run-pass needs a .mir input.\n";
412 return 1;
413 }
414 LLVMTargetMachine &LLVMTM = static_cast<LLVMTargetMachine&>(*Target);
415 TargetPassConfig *TPC = LLVMTM.createPassConfig(PM);
416 PM.add(TPC);
417 LLVMTM.addMachineModuleInfo(PM);
418 LLVMTM.addMachineFunctionAnalysis(PM, MIR.get());
419 TPC->printAndVerify("");
420
421 for (std::string &RunPassName : *RunPassNames) {
422 const PassInfo *PI = PR->getPassInfo(RunPassName);
423 if (!PI) {
424 errs() << argv[0] << ": run-pass " << RunPassName << " is not registered.\n";
425 return 1;
426 }
427
428 Pass *P;
429 if (PI->getTargetMachineCtor())
430 P = PI->getTargetMachineCtor()(Target.get());
431 else if (PI->getNormalCtor())
432 P = PI->getNormalCtor()();
433 else {
434 errs() << argv[0] << ": cannot create pass: "
435 << PI->getPassName() << "\n";
436 return 1;
437 }
438 std::string Banner
439 = std::string("After ") + std::string(P->getPassName());
440 PM.add(P);
441 TPC->printAndVerify(Banner);
442 }
443 PM.add(createPrintMIRPass(*OS));
444 } else {
445 if (!StartAfter.empty()) {
446 const PassInfo *PI = PR->getPassInfo(StartAfter);
447 if (!PI) {
448 errs() << argv[0] << ": start-after pass is not registered.\n";
449 return 1;
450 }
451 StartAfterID = PI->getTypeInfo();
452 }
453 if (!StopAfter.empty()) {
454 const PassInfo *PI = PR->getPassInfo(StopAfter);
455 if (!PI) {
456 errs() << argv[0] << ": stop-after pass is not registered.\n";
457 return 1;
458 }
459 StopAfterID = PI->getTypeInfo();
460 }
461
462 // Ask the target to add backend passes as necessary.
463 if (Target->addPassesToEmitFile(PM, *OS, FileType, NoVerify,
464 StartBeforeID, StartAfterID, StopAfterID,
465 MIR.get())) {
466 errs() << argv[0] << ": target does not support generation of this"
467 << " file type!\n";
468 return 1;
469 }
470 }
471
472 // Before executing passes, print the final values of the LLVM options.
473 cl::PrintOptionValues();
474
475 // If requested, run the pass manager over the same module again,
476 // to catch any bugs due to persistent state in the passes. Note that
477 // opt has the same functionality, so it may be worth abstracting this out
478 // in the future.
479 SmallVector<char, 0> CompileTwiceBuffer;
480 if (CompileTwice) {
481 std::unique_ptr<Module> M2(llvm::CloneModule(M.get()));
482 PM.run(*M2);
483 CompileTwiceBuffer = Buffer;
484 Buffer.clear();
485 }
486
487 PM.run(*M);
488
489 auto HasError = *static_cast<bool *>(Context.getDiagnosticContext());
490 if (HasError)
491 return 1;
492
493 // Compare the two outputs and make sure they're the same
494 if (CompileTwice) {
495 if (Buffer.size() != CompileTwiceBuffer.size() ||
496 (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) !=
497 0)) {
498 errs()
499 << "Running the pass manager twice changed the output.\n"
500 "Writing the result of the second run to the specified output\n"
501 "To generate the one-run comparison binary, just run without\n"
502 "the compile-twice option\n";
503 Out->os() << Buffer;
504 Out->keep();
505 return 1;
506 }
507 }
508
509 if (BOS) {
510 Out->os() << Buffer;
511 }
512 }
513
514 // Declare success.
515 Out->keep();
516
517 return 0;
518 }
519