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      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/CodeGen/CommandFlags.h"
     18 #include "llvm/IR/LLVMContext.h"
     19 #include "llvm/LTO/LTOCodeGenerator.h"
     20 #include "llvm/LTO/LTOModule.h"
     21 #include "llvm/Support/MemoryBuffer.h"
     22 #include "llvm/Support/Signals.h"
     23 #include "llvm/Support/TargetSelect.h"
     24 
     25 // extra command-line flags needed for LTOCodeGenerator
     26 static cl::opt<char>
     27 OptLevel("O",
     28          cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
     29                   "(default = '-O2')"),
     30          cl::Prefix,
     31          cl::ZeroOrMore,
     32          cl::init('2'));
     33 
     34 static cl::opt<bool>
     35 DisableInline("disable-inlining", cl::init(false),
     36   cl::desc("Do not run the inliner pass"));
     37 
     38 static cl::opt<bool>
     39 DisableGVNLoadPRE("disable-gvn-loadpre", cl::init(false),
     40   cl::desc("Do not run the GVN load PRE pass"));
     41 
     42 static cl::opt<bool>
     43 DisableLTOVectorization("disable-lto-vectorization", cl::init(false),
     44   cl::desc("Do not run loop or slp vectorization during LTO"));
     45 
     46 // Holds most recent error string.
     47 // *** Not thread safe ***
     48 static std::string sLastErrorString;
     49 
     50 // Holds the initialization state of the LTO module.
     51 // *** Not thread safe ***
     52 static bool initialized = false;
     53 
     54 // Holds the command-line option parsing state of the LTO module.
     55 static bool parsedOptions = false;
     56 
     57 // Initialize the configured targets if they have not been initialized.
     58 static void lto_initialize() {
     59   if (!initialized) {
     60 #ifdef LLVM_ON_WIN32
     61     // Dialog box on crash disabling doesn't work across DLL boundaries, so do
     62     // it here.
     63     llvm::sys::DisableSystemDialogsOnCrash();
     64 #endif
     65 
     66     InitializeAllTargetInfos();
     67     InitializeAllTargets();
     68     InitializeAllTargetMCs();
     69     InitializeAllAsmParsers();
     70     InitializeAllAsmPrinters();
     71     InitializeAllDisassemblers();
     72     initialized = true;
     73   }
     74 }
     75 
     76 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(LTOCodeGenerator, lto_code_gen_t)
     77 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(LTOModule, lto_module_t)
     78 
     79 // Convert the subtarget features into a string to pass to LTOCodeGenerator.
     80 static void lto_add_attrs(lto_code_gen_t cg) {
     81   LTOCodeGenerator *CG = unwrap(cg);
     82   if (MAttrs.size()) {
     83     std::string attrs;
     84     for (unsigned i = 0; i < MAttrs.size(); ++i) {
     85       if (i > 0)
     86         attrs.append(",");
     87       attrs.append(MAttrs[i]);
     88     }
     89 
     90     CG->setAttr(attrs.c_str());
     91   }
     92 
     93   if (OptLevel < '0' || OptLevel > '3')
     94     report_fatal_error("Optimization level must be between 0 and 3");
     95   CG->setOptLevel(OptLevel - '0');
     96 }
     97 
     98 extern const char* lto_get_version() {
     99   return LTOCodeGenerator::getVersionString();
    100 }
    101 
    102 const char* lto_get_error_message() {
    103   return sLastErrorString.c_str();
    104 }
    105 
    106 bool lto_module_is_object_file(const char* path) {
    107   return LTOModule::isBitcodeFile(path);
    108 }
    109 
    110 bool lto_module_is_object_file_for_target(const char* path,
    111                                           const char* target_triplet_prefix) {
    112   ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer = MemoryBuffer::getFile(path);
    113   if (!Buffer)
    114     return false;
    115   return LTOModule::isBitcodeForTarget(Buffer->get(), target_triplet_prefix);
    116 }
    117 
    118 bool lto_module_is_object_file_in_memory(const void* mem, size_t length) {
    119   return LTOModule::isBitcodeFile(mem, length);
    120 }
    121 
    122 bool
    123 lto_module_is_object_file_in_memory_for_target(const void* mem,
    124                                             size_t length,
    125                                             const char* target_triplet_prefix) {
    126   std::unique_ptr<MemoryBuffer> buffer(LTOModule::makeBuffer(mem, length));
    127   if (!buffer)
    128     return false;
    129   return LTOModule::isBitcodeForTarget(buffer.get(), target_triplet_prefix);
    130 }
    131 
    132 lto_module_t lto_module_create(const char* path) {
    133   lto_initialize();
    134   llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
    135   return wrap(LTOModule::createFromFile(path, Options, sLastErrorString));
    136 }
    137 
    138 lto_module_t lto_module_create_from_fd(int fd, const char *path, size_t size) {
    139   lto_initialize();
    140   llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
    141   return wrap(
    142       LTOModule::createFromOpenFile(fd, path, size, Options, sLastErrorString));
    143 }
    144 
    145 lto_module_t lto_module_create_from_fd_at_offset(int fd, const char *path,
    146                                                  size_t file_size,
    147                                                  size_t map_size,
    148                                                  off_t offset) {
    149   lto_initialize();
    150   llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
    151   return wrap(LTOModule::createFromOpenFileSlice(fd, path, map_size, offset,
    152                                                  Options, sLastErrorString));
    153 }
    154 
    155 lto_module_t lto_module_create_from_memory(const void* mem, size_t length) {
    156   lto_initialize();
    157   llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
    158   return wrap(LTOModule::createFromBuffer(mem, length, Options, sLastErrorString));
    159 }
    160 
    161 lto_module_t lto_module_create_from_memory_with_path(const void* mem,
    162                                                      size_t length,
    163                                                      const char *path) {
    164   lto_initialize();
    165   llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
    166   return wrap(
    167       LTOModule::createFromBuffer(mem, length, Options, sLastErrorString, path));
    168 }
    169 
    170 lto_module_t lto_module_create_in_local_context(const void *mem, size_t length,
    171                                                 const char *path) {
    172   lto_initialize();
    173   llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
    174   return wrap(LTOModule::createInLocalContext(mem, length, Options,
    175                                               sLastErrorString, path));
    176 }
    177 
    178 lto_module_t lto_module_create_in_codegen_context(const void *mem,
    179                                                   size_t length,
    180                                                   const char *path,
    181                                                   lto_code_gen_t cg) {
    182   lto_initialize();
    183   llvm::TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
    184   return wrap(LTOModule::createInContext(mem, length, Options, sLastErrorString,
    185                                          path, &unwrap(cg)->getContext()));
    186 }
    187 
    188 void lto_module_dispose(lto_module_t mod) { delete unwrap(mod); }
    189 
    190 const char* lto_module_get_target_triple(lto_module_t mod) {
    191   return unwrap(mod)->getTargetTriple().c_str();
    192 }
    193 
    194 void lto_module_set_target_triple(lto_module_t mod, const char *triple) {
    195   return unwrap(mod)->setTargetTriple(triple);
    196 }
    197 
    198 unsigned int lto_module_get_num_symbols(lto_module_t mod) {
    199   return unwrap(mod)->getSymbolCount();
    200 }
    201 
    202 const char* lto_module_get_symbol_name(lto_module_t mod, unsigned int index) {
    203   return unwrap(mod)->getSymbolName(index);
    204 }
    205 
    206 lto_symbol_attributes lto_module_get_symbol_attribute(lto_module_t mod,
    207                                                       unsigned int index) {
    208   return unwrap(mod)->getSymbolAttributes(index);
    209 }
    210 
    211 unsigned int lto_module_get_num_deplibs(lto_module_t mod) {
    212   return unwrap(mod)->getDependentLibraryCount();
    213 }
    214 
    215 const char* lto_module_get_deplib(lto_module_t mod, unsigned int index) {
    216   return unwrap(mod)->getDependentLibrary(index);
    217 }
    218 
    219 unsigned int lto_module_get_num_linkeropts(lto_module_t mod) {
    220   return unwrap(mod)->getLinkerOptCount();
    221 }
    222 
    223 const char* lto_module_get_linkeropt(lto_module_t mod, unsigned int index) {
    224   return unwrap(mod)->getLinkerOpt(index);
    225 }
    226 
    227 void lto_codegen_set_diagnostic_handler(lto_code_gen_t cg,
    228                                         lto_diagnostic_handler_t diag_handler,
    229                                         void *ctxt) {
    230   unwrap(cg)->setDiagnosticHandler(diag_handler, ctxt);
    231 }
    232 
    233 static lto_code_gen_t createCodeGen(bool InLocalContext) {
    234   lto_initialize();
    235 
    236   TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
    237 
    238   LTOCodeGenerator *CodeGen =
    239       InLocalContext ? new LTOCodeGenerator(make_unique<LLVMContext>())
    240                      : new LTOCodeGenerator();
    241   if (CodeGen)
    242     CodeGen->setTargetOptions(Options);
    243   return wrap(CodeGen);
    244 }
    245 
    246 lto_code_gen_t lto_codegen_create(void) {
    247   return createCodeGen(/* InLocalContext */ false);
    248 }
    249 
    250 lto_code_gen_t lto_codegen_create_in_local_context(void) {
    251   return createCodeGen(/* InLocalContext */ true);
    252 }
    253 
    254 void lto_codegen_dispose(lto_code_gen_t cg) { delete unwrap(cg); }
    255 
    256 bool lto_codegen_add_module(lto_code_gen_t cg, lto_module_t mod) {
    257   return !unwrap(cg)->addModule(unwrap(mod));
    258 }
    259 
    260 void lto_codegen_set_module(lto_code_gen_t cg, lto_module_t mod) {
    261   unwrap(cg)->setModule(unwrap(mod));
    262 }
    263 
    264 bool lto_codegen_set_debug_model(lto_code_gen_t cg, lto_debug_model debug) {
    265   unwrap(cg)->setDebugInfo(debug);
    266   return false;
    267 }
    268 
    269 bool lto_codegen_set_pic_model(lto_code_gen_t cg, lto_codegen_model model) {
    270   unwrap(cg)->setCodePICModel(model);
    271   return false;
    272 }
    273 
    274 void lto_codegen_set_cpu(lto_code_gen_t cg, const char *cpu) {
    275   return unwrap(cg)->setCpu(cpu);
    276 }
    277 
    278 void lto_codegen_set_assembler_path(lto_code_gen_t cg, const char *path) {
    279   // In here only for backwards compatibility. We use MC now.
    280 }
    281 
    282 void lto_codegen_set_assembler_args(lto_code_gen_t cg, const char **args,
    283                                     int nargs) {
    284   // In here only for backwards compatibility. We use MC now.
    285 }
    286 
    287 void lto_codegen_add_must_preserve_symbol(lto_code_gen_t cg,
    288                                           const char *symbol) {
    289   unwrap(cg)->addMustPreserveSymbol(symbol);
    290 }
    291 
    292 static void maybeParseOptions(lto_code_gen_t cg) {
    293   if (!parsedOptions) {
    294     unwrap(cg)->parseCodeGenDebugOptions();
    295     lto_add_attrs(cg);
    296     parsedOptions = true;
    297   }
    298 }
    299 
    300 bool lto_codegen_write_merged_modules(lto_code_gen_t cg, const char *path) {
    301   maybeParseOptions(cg);
    302   return !unwrap(cg)->writeMergedModules(path, sLastErrorString);
    303 }
    304 
    305 const void *lto_codegen_compile(lto_code_gen_t cg, size_t *length) {
    306   maybeParseOptions(cg);
    307   return unwrap(cg)->compile(length, DisableInline,
    308                              DisableGVNLoadPRE, DisableLTOVectorization,
    309                              sLastErrorString);
    310 }
    311 
    312 bool lto_codegen_optimize(lto_code_gen_t cg) {
    313   maybeParseOptions(cg);
    314   return !unwrap(cg)->optimize(DisableInline,
    315                                DisableGVNLoadPRE, DisableLTOVectorization,
    316                                sLastErrorString);
    317 }
    318 
    319 const void *lto_codegen_compile_optimized(lto_code_gen_t cg, size_t *length) {
    320   maybeParseOptions(cg);
    321   return unwrap(cg)->compileOptimized(length, sLastErrorString);
    322 }
    323 
    324 bool lto_codegen_compile_to_file(lto_code_gen_t cg, const char **name) {
    325   maybeParseOptions(cg);
    326   return !unwrap(cg)->compile_to_file(
    327       name, DisableInline, DisableGVNLoadPRE,
    328       DisableLTOVectorization, sLastErrorString);
    329 }
    330 
    331 void lto_codegen_debug_options(lto_code_gen_t cg, const char *opt) {
    332   unwrap(cg)->setCodeGenDebugOptions(opt);
    333 }
    334 
    335 unsigned int lto_api_version() { return LTO_API_VERSION; }
    336