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