lib/ExecutionEngine/JIT/JIT.cpp

   1 //===-- JIT.cpp - LLVM Just in Time Compiler ------------------------------===//
   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 tool implements a just-in-time compiler for LLVM, allowing direct
  11 // execution of LLVM bitcode in an efficient manner.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "JIT.h"
  16 #include "llvm/Constants.h"
  17 #include "llvm/DerivedTypes.h"
  18 #include "llvm/Function.h"
  19 #include "llvm/GlobalVariable.h"
  20 #include "llvm/Instructions.h"
  21 #include "llvm/ModuleProvider.h"
  22 #include "llvm/CodeGen/JITCodeEmitter.h"
  23 #include "llvm/CodeGen/MachineCodeInfo.h"
  24 #include "llvm/ExecutionEngine/GenericValue.h"
  25 #include "llvm/ExecutionEngine/JITEventListener.h"
  26 #include "llvm/Target/TargetData.h"
  27 #include "llvm/Target/TargetMachine.h"
  28 #include "llvm/Target/TargetJITInfo.h"
  29 #include "llvm/Support/Dwarf.h"
  30 #include "llvm/Support/ErrorHandling.h"
  31 #include "llvm/Support/MutexGuard.h"
  32 #include "llvm/System/DynamicLibrary.h"
  33 #include "llvm/Config/config.h"
  34
  35 using namespace llvm;
  36
  37 #ifdef __APPLE__
  38 // Apple gcc defaults to -fuse-cxa-atexit (i.e. calls __cxa_atexit instead
  39 // of atexit). It passes the address of linker generated symbol __dso_handle
  40 // to the function.
  41 // This configuration change happened at version 5330.
  42 # include <AvailabilityMacros.h>
  43 # if defined(MAC_OS_X_VERSION_10_4) && \
  44      ((MAC_OS_X_VERSION_MIN_REQUIRED > MAC_OS_X_VERSION_10_4) || \
  45       (MAC_OS_X_VERSION_MIN_REQUIRED == MAC_OS_X_VERSION_10_4 && \
  46        __APPLE_CC__ >= 5330))
  47 #  ifndef HAVE___DSO_HANDLE
  48 #   define HAVE___DSO_HANDLE 1
  49 #  endif
  50 # endif
  51 #endif
  52
  53 #if HAVE___DSO_HANDLE
  54 extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
  55 #endif
  56
  57 namespace {
  58
  59 static struct RegisterJIT {
  60   RegisterJIT() { JIT::Register(); }
  61 } JITRegistrator;
  62
  63 }
  64
  65 extern "C" void LLVMLinkInJIT() {
  66 }
  67
  68
  69 #if defined(__GNUC__) && !defined(__ARM__EABI__)
  70
  71 // libgcc defines the __register_frame function to dynamically register new
  72 // dwarf frames for exception handling. This functionality is not portable
  73 // across compilers and is only provided by GCC. We use the __register_frame
  74 // function here so that code generated by the JIT cooperates with the unwinding
  75 // runtime of libgcc. When JITting with exception handling enable, LLVM
  76 // generates dwarf frames and registers it to libgcc with __register_frame.
  77 //
  78 // The __register_frame function works with Linux.
  79 //
  80 // Unfortunately, this functionality seems to be in libgcc after the unwinding
  81 // library of libgcc for darwin was written. The code for darwin overwrites the
  82 // value updated by __register_frame with a value fetched with "keymgr".
  83 // "keymgr" is an obsolete functionality, which should be rewritten some day.
  84 // In the meantime, since "keymgr" is on all libgccs shipped with apple-gcc, we
  85 // need a workaround in LLVM which uses the "keymgr" to dynamically modify the
  86 // values of an opaque key, used by libgcc to find dwarf tables.
  87
  88 extern "C" void __register_frame(void*);
  89
  90 #if defined(__APPLE__) && MAC_OS_X_VERSION_MAX_ALLOWED <= 1050
  91 # define USE_KEYMGR 1
  92 #else
  93 # define USE_KEYMGR 0
  94 #endif
  95
  96 #if USE_KEYMGR
  97
  98 namespace {
  99
 100 // LibgccObject - This is the structure defined in libgcc. There is no #include
 101 // provided for this structure, so we also define it here. libgcc calls it
 102 // "struct object". The structure is undocumented in libgcc.
 103 struct LibgccObject {
 104   void *unused1;
 105   void *unused2;
 106   void *unused3;
 107
 108   /// frame - Pointer to the exception table.
 109   void *frame;
 110
 111   /// encoding -  The encoding of the object?
 112   union {
 113     struct {
 114       unsigned long sorted : 1;
 115       unsigned long from_array : 1;
 116       unsigned long mixed_encoding : 1;
 117       unsigned long encoding : 8;
 118       unsigned long count : 21;
 119     } b;
 120     size_t i;
 121   } encoding;
 122
 123   /// fde_end - libgcc defines this field only if some macro is defined. We
 124   /// include this field even if it may not there, to make libgcc happy.
 125   char *fde_end;
 126
 127   /// next - At least we know it's a chained list!
 128   struct LibgccObject *next;
 129 };
 130
 131 // "kemgr" stuff. Apparently, all frame tables are stored there.
 132 extern "C" void _keymgr_set_and_unlock_processwide_ptr(int, void *);
 133 extern "C" void *_keymgr_get_and_lock_processwide_ptr(int);
 134 #define KEYMGR_GCC3_DW2_OBJ_LIST        302     /* Dwarf2 object list  */
 135
 136 /// LibgccObjectInfo - libgcc defines this struct as km_object_info. It
 137 /// probably contains all dwarf tables that are loaded.
 138 struct LibgccObjectInfo {
 139
 140   /// seenObjects - LibgccObjects already parsed by the unwinding runtime.
 141   ///
 142   struct LibgccObject* seenObjects;
 143
 144   /// unseenObjects - LibgccObjects not parsed yet by the unwinding runtime.
 145   ///
 146   struct LibgccObject* unseenObjects;
 147
 148   unsigned unused[2];
 149 };
 150
 151 /// darwin_register_frame - Since __register_frame does not work with darwin's
 152 /// libgcc,we provide our own function, which "tricks" libgcc by modifying the
 153 /// "Dwarf2 object list" key.
 154 void DarwinRegisterFrame(void* FrameBegin) {
 155   // Get the key.
 156   LibgccObjectInfo* LOI = (struct LibgccObjectInfo*)
 157     _keymgr_get_and_lock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
 158   assert(LOI && "This should be preallocated by the runtime");
 159
 160   // Allocate a new LibgccObject to represent this frame. Deallocation of this
 161   // object may be impossible: since darwin code in libgcc was written after
 162   // the ability to dynamically register frames, things may crash if we
 163   // deallocate it.
 164   struct LibgccObject* ob = (struct LibgccObject*)
 165     malloc(sizeof(struct LibgccObject));
 166
 167   // Do like libgcc for the values of the field.
 168   ob->unused1 = (void *)-1;
 169   ob->unused2 = 0;
 170   ob->unused3 = 0;
 171   ob->frame = FrameBegin;
 172   ob->encoding.i = 0;
 173   ob->encoding.b.encoding = llvm::dwarf::DW_EH_PE_omit;
 174
 175   // Put the info on both places, as libgcc uses the first or the the second
 176   // field. Note that we rely on having two pointers here. If fde_end was a
 177   // char, things would get complicated.
 178   ob->fde_end = (char*)LOI->unseenObjects;
 179   ob->next = LOI->unseenObjects;
 180
 181   // Update the key's unseenObjects list.
 182   LOI->unseenObjects = ob;
 183
 184   // Finally update the "key". Apparently, libgcc requires it.
 185   _keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST,
 186                                          LOI);
 187
 188 }
 189
 190 }
 191 #endif // __APPLE__
 192 #endif // __GNUC__
 193
 194 /// createJIT - This is the factory method for creating a JIT for the current
 195 /// machine, it does not fall back to the interpreter.  This takes ownership
 196 /// of the module provider.
 197 ExecutionEngine *ExecutionEngine::createJIT(ModuleProvider *MP,
 198                                             std::string *ErrorStr,
 199                                             JITMemoryManager *JMM,
 200                                             CodeGenOpt::Level OptLevel,
 201                                             bool GVsWithCode) {
 202     return JIT::createJIT(MP, ErrorStr, JMM, OptLevel, GVsWithCode);
 203 }
 204
 205 ExecutionEngine *JIT::createJIT(ModuleProvider *MP,
 206                                 std::string *ErrorStr,
 207                                 JITMemoryManager *JMM,
 208                                 CodeGenOpt::Level OptLevel,
 209                                 bool GVsWithCode) {
 210   // Make sure we can resolve symbols in the program as well. The zero arg
 211   // to the function tells DynamicLibrary to load the program, not a library.
 212   if (sys::DynamicLibrary::LoadLibraryPermanently(0, ErrorStr))
 213     return 0;
 214
 215   // Pick a target either via -march or by guessing the native arch.
 216   TargetMachine *TM = JIT::selectTarget(MP, ErrorStr);
 217   if (!TM || (ErrorStr && ErrorStr->length() > 0)) return 0;
 218
 219   // If the target supports JIT code generation, create a the JIT.
 220   if (TargetJITInfo *TJ = TM->getJITInfo()) {
 221     return new JIT(MP, *TM, *TJ, JMM, OptLevel, GVsWithCode);
 222   } else {
 223     if (ErrorStr)
 224       *ErrorStr = "target does not support JIT code generation";
 225     return 0;
 226   }
 227 }
 228
 229 JIT::JIT(ModuleProvider *MP, TargetMachine &tm, TargetJITInfo &tji,
 230          JITMemoryManager *JMM, CodeGenOpt::Level OptLevel, bool GVsWithCode)
 231   : ExecutionEngine(MP), TM(tm), TJI(tji), AllocateGVsWithCode(GVsWithCode) {
 232   setTargetData(TM.getTargetData());
 233
 234   jitstate = new JITState(MP);
 235
 236   // Initialize JCE
 237   JCE = createEmitter(*this, JMM);
 238
 239   // Add target data
 240   MutexGuard locked(lock);
 241   FunctionPassManager &PM = jitstate->getPM(locked);
 242   PM.add(new TargetData(*TM.getTargetData()));
 243
 244   // Turn the machine code intermediate representation into bytes in memory that
 245   // may be executed.
 246   if (TM.addPassesToEmitMachineCode(PM, *JCE, OptLevel)) {
 247     llvm_report_error("Target does not support machine code emission!");
 248   }
 249
 250   // Register routine for informing unwinding runtime about new EH frames
 251 #if defined(__GNUC__) && !defined(__ARM_EABI__)
 252 #if USE_KEYMGR
 253   struct LibgccObjectInfo* LOI = (struct LibgccObjectInfo*)
 254     _keymgr_get_and_lock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
 255
 256   // The key is created on demand, and libgcc creates it the first time an
 257   // exception occurs. Since we need the key to register frames, we create
 258   // it now.
 259   if (!LOI)
 260     LOI = (LibgccObjectInfo*)calloc(sizeof(struct LibgccObjectInfo), 1);
 261   _keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST, LOI);
 262   InstallExceptionTableRegister(DarwinRegisterFrame);
 263 #else
 264   InstallExceptionTableRegister(__register_frame);
 265 #endif // __APPLE__
 266 #endif // __GNUC__
 267
 268   // Initialize passes.
 269   PM.doInitialization();
 270 }
 271
 272 JIT::~JIT() {
 273   delete jitstate;
 274   delete JCE;
 275   delete &TM;
 276 }
 277
 278 /// addModuleProvider - Add a new ModuleProvider to the JIT.  If we previously
 279 /// removed the last ModuleProvider, we need re-initialize jitstate with a valid
 280 /// ModuleProvider.
 281 void JIT::addModuleProvider(ModuleProvider *MP) {
 282   MutexGuard locked(lock);
 283
 284   if (Modules.empty()) {
 285     assert(!jitstate && "jitstate should be NULL if Modules vector is empty!");
 286
 287     jitstate = new JITState(MP);
 288
 289     FunctionPassManager &PM = jitstate->getPM(locked);
 290     PM.add(new TargetData(*TM.getTargetData()));
 291
 292     // Turn the machine code intermediate representation into bytes in memory
 293     // that may be executed.
 294     if (TM.addPassesToEmitMachineCode(PM, *JCE, CodeGenOpt::Default)) {
 295       llvm_report_error("Target does not support machine code emission!");
 296     }
 297
 298     // Initialize passes.
 299     PM.doInitialization();
 300   }
 301
 302   ExecutionEngine::addModuleProvider(MP);
 303 }
 304
 305 /// removeModuleProvider - If we are removing the last ModuleProvider,
 306 /// invalidate the jitstate since the PassManager it contains references a
 307 /// released ModuleProvider.
 308 Module *JIT::removeModuleProvider(ModuleProvider *MP, std::string *E) {
 309   Module *result = ExecutionEngine::removeModuleProvider(MP, E);
 310
 311   MutexGuard locked(lock);
 312
 313   if (jitstate->getMP() == MP) {
 314     delete jitstate;
 315     jitstate = 0;
 316   }
 317
 318   if (!jitstate && !Modules.empty()) {
 319     jitstate = new JITState(Modules[0]);
 320
 321     FunctionPassManager &PM = jitstate->getPM(locked);
 322     PM.add(new TargetData(*TM.getTargetData()));
 323
 324     // Turn the machine code intermediate representation into bytes in memory
 325     // that may be executed.
 326     if (TM.addPassesToEmitMachineCode(PM, *JCE, CodeGenOpt::Default)) {
 327       llvm_report_error("Target does not support machine code emission!");
 328     }
 329
 330     // Initialize passes.
 331     PM.doInitialization();
 332   }
 333   return result;
 334 }
 335
 336 /// deleteModuleProvider - Remove a ModuleProvider from the list of modules,
 337 /// and deletes the ModuleProvider and owned Module.  Avoids materializing
 338 /// the underlying module.
 339 void JIT::deleteModuleProvider(ModuleProvider *MP, std::string *E) {
 340   ExecutionEngine::deleteModuleProvider(MP, E);
 341
 342   MutexGuard locked(lock);
 343
 344   if (jitstate->getMP() == MP) {
 345     delete jitstate;
 346     jitstate = 0;
 347   }
 348
 349   if (!jitstate && !Modules.empty()) {
 350     jitstate = new JITState(Modules[0]);
 351
 352     FunctionPassManager &PM = jitstate->getPM(locked);
 353     PM.add(new TargetData(*TM.getTargetData()));
 354
 355     // Turn the machine code intermediate representation into bytes in memory
 356     // that may be executed.
 357     if (TM.addPassesToEmitMachineCode(PM, *JCE, CodeGenOpt::Default)) {
 358       llvm_report_error("Target does not support machine code emission!");
 359     }
 360
 361     // Initialize passes.
 362     PM.doInitialization();
 363   }
 364 }
 365
 366 /// run - Start execution with the specified function and arguments.
 367 ///
 368 GenericValue JIT::runFunction(Function *F,
 369                               const std::vector<GenericValue> &ArgValues) {
 370   assert(F && "Function *F was null at entry to run()");
 371
 372   void *FPtr = getPointerToFunction(F);
 373   assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
 374   const FunctionType *FTy = F->getFunctionType();
 375   const Type *RetTy = FTy->getReturnType();
 376
 377   assert((FTy->getNumParams() == ArgValues.size() ||
 378           (FTy->isVarArg() && FTy->getNumParams() <= ArgValues.size())) &&
 379          "Wrong number of arguments passed into function!");
 380   assert(FTy->getNumParams() == ArgValues.size() &&
 381          "This doesn't support passing arguments through varargs (yet)!");
 382
 383   // Handle some common cases first.  These cases correspond to common `main'
 384   // prototypes.
 385   if (RetTy == Type::getInt32Ty(F->getContext()) ||
 386       RetTy == Type::getVoidTy(F->getContext())) {
 387     switch (ArgValues.size()) {
 388     case 3:
 389       if (FTy->getParamType(0) == Type::getInt32Ty(F->getContext()) &&
 390           isa<PointerType>(FTy->getParamType(1)) &&
 391           isa<PointerType>(FTy->getParamType(2))) {
 392         int (*PF)(int, char **, const char **) =
 393           (int(*)(int, char **, const char **))(intptr_t)FPtr;
 394
 395         // Call the function.
 396         GenericValue rv;
 397         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
 398                                  (char **)GVTOP(ArgValues[1]),
 399                                  (const char **)GVTOP(ArgValues[2])));
 400         return rv;
 401       }
 402       break;
 403     case 2:
 404       if (FTy->getParamType(0) == Type::getInt32Ty(F->getContext()) &&
 405           isa<PointerType>(FTy->getParamType(1))) {
 406         int (*PF)(int, char **) = (int(*)(int, char **))(intptr_t)FPtr;
 407
 408         // Call the function.
 409         GenericValue rv;
 410         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
 411                                  (char **)GVTOP(ArgValues[1])));
 412         return rv;
 413       }
 414       break;
 415     case 1:
 416       if (FTy->getNumParams() == 1 &&
 417           FTy->getParamType(0) == Type::getInt32Ty(F->getContext())) {
 418         GenericValue rv;
 419         int (*PF)(int) = (int(*)(int))(intptr_t)FPtr;
 420         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
 421         return rv;
 422       }
 423       break;
 424     }
 425   }
 426
 427   // Handle cases where no arguments are passed first.
 428   if (ArgValues.empty()) {
 429     GenericValue rv;
 430     switch (RetTy->getTypeID()) {
 431     default: llvm_unreachable("Unknown return type for function call!");
 432     case Type::IntegerTyID: {
 433       unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
 434       if (BitWidth == 1)
 435         rv.IntVal = APInt(BitWidth, ((bool(*)())(intptr_t)FPtr)());
 436       else if (BitWidth <= 8)
 437         rv.IntVal = APInt(BitWidth, ((char(*)())(intptr_t)FPtr)());
 438       else if (BitWidth <= 16)
 439         rv.IntVal = APInt(BitWidth, ((short(*)())(intptr_t)FPtr)());
 440       else if (BitWidth <= 32)
 441         rv.IntVal = APInt(BitWidth, ((int(*)())(intptr_t)FPtr)());
 442       else if (BitWidth <= 64)
 443         rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
 444       else
 445         llvm_unreachable("Integer types > 64 bits not supported");
 446       return rv;
 447     }
 448     case Type::VoidTyID:
 449       rv.IntVal = APInt(32, ((int(*)())(intptr_t)FPtr)());
 450       return rv;
 451     case Type::FloatTyID:
 452       rv.FloatVal = ((float(*)())(intptr_t)FPtr)();
 453       return rv;
 454     case Type::DoubleTyID:
 455       rv.DoubleVal = ((double(*)())(intptr_t)FPtr)();
 456       return rv;
 457     case Type::X86_FP80TyID:
 458     case Type::FP128TyID:
 459     case Type::PPC_FP128TyID:
 460       llvm_unreachable("long double not supported yet");
 461       return rv;
 462     case Type::PointerTyID:
 463       return PTOGV(((void*(*)())(intptr_t)FPtr)());
 464     }
 465   }
 466
 467   // Okay, this is not one of our quick and easy cases.  Because we don't have a
 468   // full FFI, we have to codegen a nullary stub function that just calls the
 469   // function we are interested in, passing in constants for all of the
 470   // arguments.  Make this function and return.
 471
 472   // First, create the function.
 473   FunctionType *STy=FunctionType::get(RetTy, false);
 474   Function *Stub = Function::Create(STy, Function::InternalLinkage, "",
 475                                     F->getParent());
 476
 477   // Insert a basic block.
 478   BasicBlock *StubBB = BasicBlock::Create(F->getContext(), "", Stub);
 479
 480   // Convert all of the GenericValue arguments over to constants.  Note that we
 481   // currently don't support varargs.
 482   SmallVector<Value*, 8> Args;
 483   for (unsigned i = 0, e = ArgValues.size(); i != e; ++i) {
 484     Constant *C = 0;
 485     const Type *ArgTy = FTy->getParamType(i);
 486     const GenericValue &AV = ArgValues[i];
 487     switch (ArgTy->getTypeID()) {
 488     default: llvm_unreachable("Unknown argument type for function call!");
 489     case Type::IntegerTyID:
 490         C = ConstantInt::get(F->getContext(), AV.IntVal);
 491         break;
 492     case Type::FloatTyID:
 493         C = ConstantFP::get(F->getContext(), APFloat(AV.FloatVal));
 494         break;
 495     case Type::DoubleTyID:
 496         C = ConstantFP::get(F->getContext(), APFloat(AV.DoubleVal));
 497         break;
 498     case Type::PPC_FP128TyID:
 499     case Type::X86_FP80TyID:
 500     case Type::FP128TyID:
 501         C = ConstantFP::get(F->getContext(), APFloat(AV.IntVal));
 502         break;
 503     case Type::PointerTyID:
 504       void *ArgPtr = GVTOP(AV);
 505       if (sizeof(void*) == 4)
 506         C = ConstantInt::get(Type::getInt32Ty(F->getContext()),
 507                              (int)(intptr_t)ArgPtr);
 508       else
 509         C = ConstantInt::get(Type::getInt64Ty(F->getContext()),
 510                              (intptr_t)ArgPtr);
 511       // Cast the integer to pointer
 512       C = ConstantExpr::getIntToPtr(C, ArgTy);
 513       break;
 514     }
 515     Args.push_back(C);
 516   }
 517
 518   CallInst *TheCall = CallInst::Create(F, Args.begin(), Args.end(),
 519                                        "", StubBB);
 520   TheCall->setCallingConv(F->getCallingConv());
 521   TheCall->setTailCall();
 522   if (TheCall->getType() != Type::getVoidTy(F->getContext()))
 523     // Return result of the call.
 524     ReturnInst::Create(F->getContext(), TheCall, StubBB);
 525   else
 526     ReturnInst::Create(F->getContext(), StubBB);           // Just return void.
 527
 528   // Finally, return the value returned by our nullary stub function.
 529   return runFunction(Stub, std::vector<GenericValue>());
 530 }
 531
 532 void JIT::RegisterJITEventListener(JITEventListener *L) {
 533   if (L == NULL)
 534     return;
 535   MutexGuard locked(lock);
 536   EventListeners.push_back(L);
 537 }
 538 void JIT::UnregisterJITEventListener(JITEventListener *L) {
 539   if (L == NULL)
 540     return;
 541   MutexGuard locked(lock);
 542   std::vector<JITEventListener*>::reverse_iterator I=
 543       std::find(EventListeners.rbegin(), EventListeners.rend(), L);
 544   if (I != EventListeners.rend()) {
 545     std::swap(*I, EventListeners.back());
 546     EventListeners.pop_back();
 547   }
 548 }
 549 void JIT::NotifyFunctionEmitted(
 550     const Function &F,
 551     void *Code, size_t Size,
 552     const JITEvent_EmittedFunctionDetails &Details) {
 553   MutexGuard locked(lock);
 554   for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
 555     EventListeners[I]->NotifyFunctionEmitted(F, Code, Size, Details);
 556   }
 557 }
 558
 559 void JIT::NotifyFreeingMachineCode(const Function &F, void *OldPtr) {
 560   MutexGuard locked(lock);
 561   for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
 562     EventListeners[I]->NotifyFreeingMachineCode(F, OldPtr);
 563   }
 564 }
 565
 566 /// runJITOnFunction - Run the FunctionPassManager full of
 567 /// just-in-time compilation passes on F, hopefully filling in
 568 /// GlobalAddress[F] with the address of F's machine code.
 569 ///
 570 void JIT::runJITOnFunction(Function *F, MachineCodeInfo *MCI) {
 571   MutexGuard locked(lock);
 572
 573   class MCIListener : public JITEventListener {
 574     MachineCodeInfo *const MCI;
 575    public:
 576     MCIListener(MachineCodeInfo *mci) : MCI(mci) {}
 577     virtual void NotifyFunctionEmitted(const Function &,
 578                                        void *Code, size_t Size,
 579                                        const EmittedFunctionDetails &) {
 580       MCI->setAddress(Code);
 581       MCI->setSize(Size);
 582     }
 583   };
 584   MCIListener MCIL(MCI);
 585   RegisterJITEventListener(&MCIL);
 586
 587   runJITOnFunctionUnlocked(F, locked);
 588
 589   UnregisterJITEventListener(&MCIL);
 590 }
 591
 592 void JIT::runJITOnFunctionUnlocked(Function *F, const MutexGuard &locked) {
 593   static bool isAlreadyCodeGenerating = false;
 594   assert(!isAlreadyCodeGenerating && "Error: Recursive compilation detected!");
 595
 596   // JIT the function
 597   isAlreadyCodeGenerating = true;
 598   jitstate->getPM(locked).run(*F);
 599   isAlreadyCodeGenerating = false;
 600
 601   // If the function referred to another function that had not yet been
 602   // read from bitcode, but we are jitting non-lazily, emit it now.
 603   while (!jitstate->getPendingFunctions(locked).empty()) {
 604     Function *PF = jitstate->getPendingFunctions(locked).back();
 605     jitstate->getPendingFunctions(locked).pop_back();
 606
 607     // JIT the function
 608     isAlreadyCodeGenerating = true;
 609     jitstate->getPM(locked).run(*PF);
 610     isAlreadyCodeGenerating = false;
 611
 612     // Now that the function has been jitted, ask the JITEmitter to rewrite
 613     // the stub with real address of the function.
 614     updateFunctionStub(PF);
 615   }
 616
 617   // If the JIT is configured to emit info so that dlsym can be used to
 618   // rewrite stubs to external globals, do so now.
 619   if (areDlsymStubsEnabled() && isLazyCompilationDisabled())
 620     updateDlsymStubTable();
 621 }
 622
 623 /// getPointerToFunction - This method is used to get the address of the
 624 /// specified function, compiling it if neccesary.
 625 ///
 626 void *JIT::getPointerToFunction(Function *F) {
 627
 628   if (void *Addr = getPointerToGlobalIfAvailable(F))
 629     return Addr;   // Check if function already code gen'd
 630
 631   MutexGuard locked(lock);
 632
 633   // Now that this thread owns the lock, check if another thread has already
 634   // code gen'd the function.
 635   if (void *Addr = getPointerToGlobalIfAvailable(F))
 636     return Addr;
 637
 638   // Make sure we read in the function if it exists in this Module.
 639   if (F->hasNotBeenReadFromBitcode()) {
 640     // Determine the module provider this function is provided by.
 641     Module *M = F->getParent();
 642     ModuleProvider *MP = 0;
 643     for (unsigned i = 0, e = Modules.size(); i != e; ++i) {
 644       if (Modules[i]->getModule() == M) {
 645         MP = Modules[i];
 646         break;
 647       }
 648     }
 649     assert(MP && "Function isn't in a module we know about!");
 650
 651     std::string ErrorMsg;
 652     if (MP->materializeFunction(F, &ErrorMsg)) {
 653       llvm_report_error("Error reading function '" + F->getName()+
 654                         "' from bitcode file: " + ErrorMsg);
 655     }
 656
 657     // Now retry to get the address.
 658     if (void *Addr = getPointerToGlobalIfAvailable(F))
 659       return Addr;
 660   }
 661
 662   if (F->isDeclaration()) {
 663     bool AbortOnFailure =
 664       !areDlsymStubsEnabled() && !F->hasExternalWeakLinkage();
 665     void *Addr = getPointerToNamedFunction(F->getName(), AbortOnFailure);
 666     addGlobalMapping(F, Addr);
 667     return Addr;
 668   }
 669
 670   runJITOnFunctionUnlocked(F, locked);
 671
 672   void *Addr = getPointerToGlobalIfAvailable(F);
 673   assert(Addr && "Code generation didn't add function to GlobalAddress table!");
 674   return Addr;
 675 }
 676
 677 /// getOrEmitGlobalVariable - Return the address of the specified global
 678 /// variable, possibly emitting it to memory if needed.  This is used by the
 679 /// Emitter.
 680 void *JIT::getOrEmitGlobalVariable(const GlobalVariable *GV) {
 681   MutexGuard locked(lock);
 682
 683   void *Ptr = getPointerToGlobalIfAvailable(GV);
 684   if (Ptr) return Ptr;
 685
 686   // If the global is external, just remember the address.
 687   if (GV->isDeclaration()) {
 688 #if HAVE___DSO_HANDLE
 689     if (GV->getName() == "__dso_handle")
 690       return (void*)&__dso_handle;
 691 #endif
 692     Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(GV->getName());
 693     if (Ptr == 0 && !areDlsymStubsEnabled()) {
 694       llvm_report_error("Could not resolve external global address: "
 695                         +GV->getName());
 696     }
 697     addGlobalMapping(GV, Ptr);
 698   } else {
 699     // If the global hasn't been emitted to memory yet, allocate space and
 700     // emit it into memory.
 701     Ptr = getMemoryForGV(GV);
 702     addGlobalMapping(GV, Ptr);
 703     EmitGlobalVariable(GV);  // Initialize the variable.
 704   }
 705   return Ptr;
 706 }
 707
 708 /// recompileAndRelinkFunction - This method is used to force a function
 709 /// which has already been compiled, to be compiled again, possibly
 710 /// after it has been modified. Then the entry to the old copy is overwritten
 711 /// with a branch to the new copy. If there was no old copy, this acts
 712 /// just like JIT::getPointerToFunction().
 713 ///
 714 void *JIT::recompileAndRelinkFunction(Function *F) {
 715   void *OldAddr = getPointerToGlobalIfAvailable(F);
 716
 717   // If it's not already compiled there is no reason to patch it up.
 718   if (OldAddr == 0) { return getPointerToFunction(F); }
 719
 720   // Delete the old function mapping.
 721   addGlobalMapping(F, 0);
 722
 723   // Recodegen the function
 724   runJITOnFunction(F);
 725
 726   // Update state, forward the old function to the new function.
 727   void *Addr = getPointerToGlobalIfAvailable(F);
 728   assert(Addr && "Code generation didn't add function to GlobalAddress table!");
 729   TJI.replaceMachineCodeForFunction(OldAddr, Addr);
 730   return Addr;
 731 }
 732
 733 /// getMemoryForGV - This method abstracts memory allocation of global
 734 /// variable so that the JIT can allocate thread local variables depending
 735 /// on the target.
 736 ///
 737 char* JIT::getMemoryForGV(const GlobalVariable* GV) {
 738   char *Ptr;
 739
 740   // GlobalVariable's which are not "constant" will cause trouble in a server
 741   // situation. It's returned in the same block of memory as code which may
 742   // not be writable.
 743   if (isGVCompilationDisabled() && !GV->isConstant()) {
 744     llvm_report_error("Compilation of non-internal GlobalValue is disabled!");
 745   }
 746
 747   // Some applications require globals and code to live together, so they may
 748   // be allocated into the same buffer, but in general globals are allocated
 749   // through the memory manager which puts them near the code but not in the
 750   // same buffer.
 751   const Type *GlobalType = GV->getType()->getElementType();
 752   size_t S = getTargetData()->getTypeAllocSize(GlobalType);
 753   size_t A = getTargetData()->getPreferredAlignment(GV);
 754   if (GV->isThreadLocal()) {
 755     MutexGuard locked(lock);
 756     Ptr = TJI.allocateThreadLocalMemory(S);
 757   } else if (TJI.allocateSeparateGVMemory()) {
 758     if (A <= 8) {
 759       Ptr = (char*)malloc(S);
 760     } else {
 761       // Allocate S+A bytes of memory, then use an aligned pointer within that
 762       // space.
 763       Ptr = (char*)malloc(S+A);
 764       unsigned MisAligned = ((intptr_t)Ptr & (A-1));
 765       Ptr = Ptr + (MisAligned ? (A-MisAligned) : 0);
 766     }
 767   } else if (AllocateGVsWithCode) {
 768     Ptr = (char*)JCE->allocateSpace(S, A);
 769   } else {
 770     Ptr = (char*)JCE->allocateGlobal(S, A);
 771   }
 772   return Ptr;
 773 }
 774
 775 void JIT::addPendingFunction(Function *F) {
 776   MutexGuard locked(lock);
 777   jitstate->getPendingFunctions(locked).push_back(F);
 778 }
 779
 780
 781 JITEventListener::~JITEventListener() {}