1//===-lto.cpp - LLVM Link Time Optimizer ----------------------------------===//
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 file implements the Link Time Optimization library. This library is
11// intended to be used by linker to optimize code at link time.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm-c/lto.h"
16#include "llvm/ADT/STLExtras.h"
17#include "llvm/Bitcode/ReaderWriter.h"
18#include "llvm/CodeGen/CommandFlags.h"
19#include "llvm/IR/DiagnosticInfo.h"
20#include "llvm/IR/DiagnosticPrinter.h"
21#include "llvm/IR/LLVMContext.h"
22#include "llvm/LTO/legacy/LTOCodeGenerator.h"
23#include "llvm/LTO/legacy/LTOModule.h"
24#include "llvm/LTO/legacy/ThinLTOCodeGenerator.h"
25#include "llvm/Support/MemoryBuffer.h"
26#include "llvm/Support/Signals.h"
27#include "llvm/Support/TargetSelect.h"
28#include "llvm/Support/raw_ostream.h"
29
30// extra command-line flags needed for LTOCodeGenerator
31static cl::opt<char>
32OptLevel("O",
33         cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
34                  "(default = '-O2')"),
35         cl::Prefix,
36         cl::ZeroOrMore,
37         cl::init('2'));
38
39static cl::opt<bool>
40DisableInline("disable-inlining", cl::init(false),
41  cl::desc("Do not run the inliner pass"));
42
43static cl::opt<bool>
44DisableGVNLoadPRE("disable-gvn-loadpre", cl::init(false),
45  cl::desc("Do not run the GVN load PRE pass"));
46
47static cl::opt<bool>
48DisableLTOVectorization("disable-lto-vectorization", cl::init(false),
49  cl::desc("Do not run loop or slp vectorization during LTO"));
50
51#ifdef NDEBUG
52static bool VerifyByDefault = false;
53#else
54static bool VerifyByDefault = true;
55#endif
56
57static cl::opt<bool> DisableVerify(
58    "disable-llvm-verifier", cl::init(!VerifyByDefault),
59    cl::desc("Don't run the LLVM verifier during the optimization pipeline"));
60
61// Holds most recent error string.
62// *** Not thread safe ***
63static std::string sLastErrorString;
64
65// Holds the initialization state of the LTO module.
66// *** Not thread safe ***
67static bool initialized = false;
68
69// Holds the command-line option parsing state of the LTO module.
70static bool parsedOptions = false;
71
72static LLVMContext *LTOContext = nullptr;
73
74static void diagnosticHandler(const DiagnosticInfo &DI, void *Context) {
75  if (DI.getSeverity() != DS_Error) {
76    DiagnosticPrinterRawOStream DP(errs());
77    DI.print(DP);
78    errs() << '\n';
79    return;
80  }
81  sLastErrorString = "";
82  {
83    raw_string_ostream Stream(sLastErrorString);
84    DiagnosticPrinterRawOStream DP(Stream);
85    DI.print(DP);
86  }
87}
88
89// Initialize the configured targets if they have not been initialized.
90static void lto_initialize() {
91  if (!initialized) {
92#ifdef LLVM_ON_WIN32
93    // Dialog box on crash disabling doesn't work across DLL boundaries, so do
94    // it here.
95    llvm::sys::DisableSystemDialogsOnCrash();
96#endif
97
98    InitializeAllTargetInfos();
99    InitializeAllTargets();
100    InitializeAllTargetMCs();
101    InitializeAllAsmParsers();
102    InitializeAllAsmPrinters();
103    InitializeAllDisassemblers();
104
105    static LLVMContext Context;
106    LTOContext = &Context;
107    LTOContext->setDiagnosticHandler(diagnosticHandler, nullptr, true);
108    initialized = true;
109  }
110}
111
112namespace {
113
114static void handleLibLTODiagnostic(lto_codegen_diagnostic_severity_t Severity,
115                                   const char *Msg, void *) {
116  sLastErrorString = Msg;
117}
118
119// This derived class owns the native object file. This helps implement the
120// libLTO API semantics, which require that the code generator owns the object
121// file.
122struct LibLTOCodeGenerator : LTOCodeGenerator {
123  LibLTOCodeGenerator() : LTOCodeGenerator(*LTOContext) { init(); }
124  LibLTOCodeGenerator(std::unique_ptr<LLVMContext> Context)
125      : LTOCodeGenerator(*Context), OwnedContext(std::move(Context)) {
126    init();
127  }
128
129  // Reset the module first in case MergedModule is created in OwnedContext.
130  // Module must be destructed before its context gets destructed.
131  ~LibLTOCodeGenerator() { resetMergedModule(); }
132
133  void init() { setDiagnosticHandler(handleLibLTODiagnostic, nullptr); }
134
135  std::unique_ptr<MemoryBuffer> NativeObjectFile;
136  std::unique_ptr<LLVMContext> OwnedContext;
137};
138
139}
140
141DEFINE_SIMPLE_CONVERSION_FUNCTIONS(LibLTOCodeGenerator, lto_code_gen_t)
142DEFINE_SIMPLE_CONVERSION_FUNCTIONS(ThinLTOCodeGenerator, thinlto_code_gen_t)
143DEFINE_SIMPLE_CONVERSION_FUNCTIONS(LTOModule, lto_module_t)
144
145// Convert the subtarget features into a string to pass to LTOCodeGenerator.
146static void lto_add_attrs(lto_code_gen_t cg) {
147  LTOCodeGenerator *CG = unwrap(cg);
148  if (MAttrs.size()) {
149    std::string attrs;
150    for (unsigned i = 0; i < MAttrs.size(); ++i) {
151      if (i > 0)
152        attrs.append(",");
153      attrs.append(MAttrs[i]);
154    }
155
156    CG->setAttr(attrs.c_str());
157  }
158
159  if (OptLevel < '0' || OptLevel > '3')
160    report_fatal_error("Optimization level must be between 0 and 3");
161  CG->setOptLevel(OptLevel - '0');
162}
163
164extern const char* lto_get_version() {
165  return LTOCodeGenerator::getVersionString();
166}
167
168const char* lto_get_error_message() {
169  return sLastErrorString.c_str();
170}
171
172bool lto_module_is_object_file(const char* path) {
173  return LTOModule::isBitcodeFile(path);
174}
175
176bool lto_module_is_object_file_for_target(const char* path,
177                                          const char* target_triplet_prefix) {
178  ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer = MemoryBuffer::getFile(path);
179  if (!Buffer)
180    return false;
181  return LTOModule::isBitcodeForTarget(Buffer->get(), target_triplet_prefix);
182}
183
184bool lto_module_has_objc_category(const void *mem, size_t length) {
185  std::unique_ptr<MemoryBuffer> Buffer(LTOModule::makeBuffer(mem, length));
186  if (!Buffer)
187    return false;
188  LLVMContext Ctx;
189  return llvm::isBitcodeContainingObjCCategory(*Buffer, Ctx);
190}
191
192bool lto_module_is_object_file_in_memory(const void* mem, size_t length) {
193  return LTOModule::isBitcodeFile(mem, length);
194}
195
196bool
197lto_module_is_object_file_in_memory_for_target(const void* mem,
198                                            size_t length,
199                                            const char* target_triplet_prefix) {
200  std::unique_ptr<MemoryBuffer> buffer(LTOModule::makeBuffer(mem, length));
201  if (!buffer)
202    return false;
203  return LTOModule::isBitcodeForTarget(buffer.get(), target_triplet_prefix);
204}
205
206lto_module_t lto_module_create(const char* path) {
207  lto_initialize();
208  llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
209  ErrorOr<std::unique_ptr<LTOModule>> M =
210      LTOModule::createFromFile(*LTOContext, path, Options);
211  if (!M)
212    return nullptr;
213  return wrap(M->release());
214}
215
216lto_module_t lto_module_create_from_fd(int fd, const char *path, size_t size) {
217  lto_initialize();
218  llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
219  ErrorOr<std::unique_ptr<LTOModule>> M =
220      LTOModule::createFromOpenFile(*LTOContext, fd, path, size, Options);
221  if (!M)
222    return nullptr;
223  return wrap(M->release());
224}
225
226lto_module_t lto_module_create_from_fd_at_offset(int fd, const char *path,
227                                                 size_t file_size,
228                                                 size_t map_size,
229                                                 off_t offset) {
230  lto_initialize();
231  llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
232  ErrorOr<std::unique_ptr<LTOModule>> M = LTOModule::createFromOpenFileSlice(
233      *LTOContext, fd, path, map_size, offset, Options);
234  if (!M)
235    return nullptr;
236  return wrap(M->release());
237}
238
239lto_module_t lto_module_create_from_memory(const void* mem, size_t length) {
240  lto_initialize();
241  llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
242  ErrorOr<std::unique_ptr<LTOModule>> M =
243      LTOModule::createFromBuffer(*LTOContext, mem, length, Options);
244  if (!M)
245    return nullptr;
246  return wrap(M->release());
247}
248
249lto_module_t lto_module_create_from_memory_with_path(const void* mem,
250                                                     size_t length,
251                                                     const char *path) {
252  lto_initialize();
253  llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
254  ErrorOr<std::unique_ptr<LTOModule>> M =
255      LTOModule::createFromBuffer(*LTOContext, mem, length, Options, path);
256  if (!M)
257    return nullptr;
258  return wrap(M->release());
259}
260
261lto_module_t lto_module_create_in_local_context(const void *mem, size_t length,
262                                                const char *path) {
263  lto_initialize();
264  llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
265
266  // Create a local context. Ownership will be transfered to LTOModule.
267  std::unique_ptr<LLVMContext> Context = llvm::make_unique<LLVMContext>();
268  Context->setDiagnosticHandler(diagnosticHandler, nullptr, true);
269
270  ErrorOr<std::unique_ptr<LTOModule>> M =
271      LTOModule::createInLocalContext(std::move(Context), mem, length, Options,
272                                      path);
273  if (!M)
274    return nullptr;
275  return wrap(M->release());
276}
277
278lto_module_t lto_module_create_in_codegen_context(const void *mem,
279                                                  size_t length,
280                                                  const char *path,
281                                                  lto_code_gen_t cg) {
282  lto_initialize();
283  llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
284  ErrorOr<std::unique_ptr<LTOModule>> M = LTOModule::createFromBuffer(
285      unwrap(cg)->getContext(), mem, length, Options, path);
286  return wrap(M->release());
287}
288
289void lto_module_dispose(lto_module_t mod) { delete unwrap(mod); }
290
291const char* lto_module_get_target_triple(lto_module_t mod) {
292  return unwrap(mod)->getTargetTriple().c_str();
293}
294
295void lto_module_set_target_triple(lto_module_t mod, const char *triple) {
296  return unwrap(mod)->setTargetTriple(triple);
297}
298
299unsigned int lto_module_get_num_symbols(lto_module_t mod) {
300  return unwrap(mod)->getSymbolCount();
301}
302
303const char* lto_module_get_symbol_name(lto_module_t mod, unsigned int index) {
304  return unwrap(mod)->getSymbolName(index);
305}
306
307lto_symbol_attributes lto_module_get_symbol_attribute(lto_module_t mod,
308                                                      unsigned int index) {
309  return unwrap(mod)->getSymbolAttributes(index);
310}
311
312const char* lto_module_get_linkeropts(lto_module_t mod) {
313  return unwrap(mod)->getLinkerOpts();
314}
315
316void lto_codegen_set_diagnostic_handler(lto_code_gen_t cg,
317                                        lto_diagnostic_handler_t diag_handler,
318                                        void *ctxt) {
319  unwrap(cg)->setDiagnosticHandler(diag_handler, ctxt);
320}
321
322static lto_code_gen_t createCodeGen(bool InLocalContext) {
323  lto_initialize();
324
325  TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
326
327  LibLTOCodeGenerator *CodeGen =
328      InLocalContext ? new LibLTOCodeGenerator(make_unique<LLVMContext>())
329                     : new LibLTOCodeGenerator();
330  CodeGen->setTargetOptions(Options);
331  return wrap(CodeGen);
332}
333
334lto_code_gen_t lto_codegen_create(void) {
335  return createCodeGen(/* InLocalContext */ false);
336}
337
338lto_code_gen_t lto_codegen_create_in_local_context(void) {
339  return createCodeGen(/* InLocalContext */ true);
340}
341
342void lto_codegen_dispose(lto_code_gen_t cg) { delete unwrap(cg); }
343
344bool lto_codegen_add_module(lto_code_gen_t cg, lto_module_t mod) {
345  return !unwrap(cg)->addModule(unwrap(mod));
346}
347
348void lto_codegen_set_module(lto_code_gen_t cg, lto_module_t mod) {
349  unwrap(cg)->setModule(std::unique_ptr<LTOModule>(unwrap(mod)));
350}
351
352bool lto_codegen_set_debug_model(lto_code_gen_t cg, lto_debug_model debug) {
353  unwrap(cg)->setDebugInfo(debug);
354  return false;
355}
356
357bool lto_codegen_set_pic_model(lto_code_gen_t cg, lto_codegen_model model) {
358  switch (model) {
359  case LTO_CODEGEN_PIC_MODEL_STATIC:
360    unwrap(cg)->setCodePICModel(Reloc::Static);
361    return false;
362  case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
363    unwrap(cg)->setCodePICModel(Reloc::PIC_);
364    return false;
365  case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
366    unwrap(cg)->setCodePICModel(Reloc::DynamicNoPIC);
367    return false;
368  case LTO_CODEGEN_PIC_MODEL_DEFAULT:
369    unwrap(cg)->setCodePICModel(None);
370    return false;
371  }
372  sLastErrorString = "Unknown PIC model";
373  return true;
374}
375
376void lto_codegen_set_cpu(lto_code_gen_t cg, const char *cpu) {
377  return unwrap(cg)->setCpu(cpu);
378}
379
380void lto_codegen_set_assembler_path(lto_code_gen_t cg, const char *path) {
381  // In here only for backwards compatibility. We use MC now.
382}
383
384void lto_codegen_set_assembler_args(lto_code_gen_t cg, const char **args,
385                                    int nargs) {
386  // In here only for backwards compatibility. We use MC now.
387}
388
389void lto_codegen_add_must_preserve_symbol(lto_code_gen_t cg,
390                                          const char *symbol) {
391  unwrap(cg)->addMustPreserveSymbol(symbol);
392}
393
394static void maybeParseOptions(lto_code_gen_t cg) {
395  if (!parsedOptions) {
396    unwrap(cg)->parseCodeGenDebugOptions();
397    lto_add_attrs(cg);
398    parsedOptions = true;
399  }
400}
401
402bool lto_codegen_write_merged_modules(lto_code_gen_t cg, const char *path) {
403  maybeParseOptions(cg);
404  return !unwrap(cg)->writeMergedModules(path);
405}
406
407const void *lto_codegen_compile(lto_code_gen_t cg, size_t *length) {
408  maybeParseOptions(cg);
409  LibLTOCodeGenerator *CG = unwrap(cg);
410  CG->NativeObjectFile =
411      CG->compile(DisableVerify, DisableInline, DisableGVNLoadPRE,
412                  DisableLTOVectorization);
413  if (!CG->NativeObjectFile)
414    return nullptr;
415  *length = CG->NativeObjectFile->getBufferSize();
416  return CG->NativeObjectFile->getBufferStart();
417}
418
419bool lto_codegen_optimize(lto_code_gen_t cg) {
420  maybeParseOptions(cg);
421  return !unwrap(cg)->optimize(DisableVerify, DisableInline, DisableGVNLoadPRE,
422                               DisableLTOVectorization);
423}
424
425const void *lto_codegen_compile_optimized(lto_code_gen_t cg, size_t *length) {
426  maybeParseOptions(cg);
427  LibLTOCodeGenerator *CG = unwrap(cg);
428  CG->NativeObjectFile = CG->compileOptimized();
429  if (!CG->NativeObjectFile)
430    return nullptr;
431  *length = CG->NativeObjectFile->getBufferSize();
432  return CG->NativeObjectFile->getBufferStart();
433}
434
435bool lto_codegen_compile_to_file(lto_code_gen_t cg, const char **name) {
436  maybeParseOptions(cg);
437  return !unwrap(cg)->compile_to_file(
438      name, DisableVerify, DisableInline, DisableGVNLoadPRE,
439      DisableLTOVectorization);
440}
441
442void lto_codegen_debug_options(lto_code_gen_t cg, const char *opt) {
443  unwrap(cg)->setCodeGenDebugOptions(opt);
444}
445
446unsigned int lto_api_version() { return LTO_API_VERSION; }
447
448void lto_codegen_set_should_internalize(lto_code_gen_t cg,
449                                        bool ShouldInternalize) {
450  unwrap(cg)->setShouldInternalize(ShouldInternalize);
451}
452
453void lto_codegen_set_should_embed_uselists(lto_code_gen_t cg,
454                                           lto_bool_t ShouldEmbedUselists) {
455  unwrap(cg)->setShouldEmbedUselists(ShouldEmbedUselists);
456}
457
458// ThinLTO API below
459
460thinlto_code_gen_t thinlto_create_codegen(void) {
461  lto_initialize();
462  ThinLTOCodeGenerator *CodeGen = new ThinLTOCodeGenerator();
463  CodeGen->setTargetOptions(InitTargetOptionsFromCodeGenFlags());
464
465  return wrap(CodeGen);
466}
467
468void thinlto_codegen_dispose(thinlto_code_gen_t cg) { delete unwrap(cg); }
469
470void thinlto_codegen_add_module(thinlto_code_gen_t cg, const char *Identifier,
471                                const char *Data, int Length) {
472  unwrap(cg)->addModule(Identifier, StringRef(Data, Length));
473}
474
475void thinlto_codegen_process(thinlto_code_gen_t cg) { unwrap(cg)->run(); }
476
477unsigned int thinlto_module_get_num_objects(thinlto_code_gen_t cg) {
478  return unwrap(cg)->getProducedBinaries().size();
479}
480LTOObjectBuffer thinlto_module_get_object(thinlto_code_gen_t cg,
481                                          unsigned int index) {
482  assert(index < unwrap(cg)->getProducedBinaries().size() && "Index overflow");
483  auto &MemBuffer = unwrap(cg)->getProducedBinaries()[index];
484  return LTOObjectBuffer{MemBuffer->getBufferStart(),
485                         MemBuffer->getBufferSize()};
486}
487
488void thinlto_codegen_disable_codegen(thinlto_code_gen_t cg,
489                                     lto_bool_t disable) {
490  unwrap(cg)->disableCodeGen(disable);
491}
492
493void thinlto_codegen_set_codegen_only(thinlto_code_gen_t cg,
494                                      lto_bool_t CodeGenOnly) {
495  unwrap(cg)->setCodeGenOnly(CodeGenOnly);
496}
497
498void thinlto_debug_options(const char *const *options, int number) {
499  // if options were requested, set them
500  if (number && options) {
501    std::vector<const char *> CodegenArgv(1, "libLTO");
502    for (auto Arg : ArrayRef<const char *>(options, number))
503      CodegenArgv.push_back(Arg);
504    cl::ParseCommandLineOptions(CodegenArgv.size(), CodegenArgv.data());
505  }
506}
507
508lto_bool_t lto_module_is_thinlto(lto_module_t mod) {
509  return unwrap(mod)->isThinLTO();
510}
511
512void thinlto_codegen_add_must_preserve_symbol(thinlto_code_gen_t cg,
513                                              const char *Name, int Length) {
514  unwrap(cg)->preserveSymbol(StringRef(Name, Length));
515}
516
517void thinlto_codegen_add_cross_referenced_symbol(thinlto_code_gen_t cg,
518                                                 const char *Name, int Length) {
519  unwrap(cg)->crossReferenceSymbol(StringRef(Name, Length));
520}
521
522void thinlto_codegen_set_cpu(thinlto_code_gen_t cg, const char *cpu) {
523  return unwrap(cg)->setCpu(cpu);
524}
525
526void thinlto_codegen_set_cache_dir(thinlto_code_gen_t cg,
527                                   const char *cache_dir) {
528  return unwrap(cg)->setCacheDir(cache_dir);
529}
530
531void thinlto_codegen_set_cache_pruning_interval(thinlto_code_gen_t cg,
532                                                int interval) {
533  return unwrap(cg)->setCachePruningInterval(interval);
534}
535
536void thinlto_codegen_set_cache_entry_expiration(thinlto_code_gen_t cg,
537                                                unsigned expiration) {
538  return unwrap(cg)->setCacheEntryExpiration(expiration);
539}
540
541void thinlto_codegen_set_final_cache_size_relative_to_available_space(
542    thinlto_code_gen_t cg, unsigned Percentage) {
543  return unwrap(cg)->setMaxCacheSizeRelativeToAvailableSpace(Percentage);
544}
545
546void thinlto_codegen_set_savetemps_dir(thinlto_code_gen_t cg,
547                                       const char *save_temps_dir) {
548  return unwrap(cg)->setSaveTempsDir(save_temps_dir);
549}
550
551lto_bool_t thinlto_codegen_set_pic_model(thinlto_code_gen_t cg,
552                                         lto_codegen_model model) {
553  switch (model) {
554  case LTO_CODEGEN_PIC_MODEL_STATIC:
555    unwrap(cg)->setCodePICModel(Reloc::Static);
556    return false;
557  case LTO_CODEGEN_PIC_MODEL_DYNAMIC:
558    unwrap(cg)->setCodePICModel(Reloc::PIC_);
559    return false;
560  case LTO_CODEGEN_PIC_MODEL_DYNAMIC_NO_PIC:
561    unwrap(cg)->setCodePICModel(Reloc::DynamicNoPIC);
562    return false;
563  case LTO_CODEGEN_PIC_MODEL_DEFAULT:
564    unwrap(cg)->setCodePICModel(None);
565    return false;
566  }
567  sLastErrorString = "Unknown PIC model";
568  return true;
569}
570