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      1 //===-- MCJIT.cpp - MC-based 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 #include "MCJIT.h"
     11 #include "llvm/ExecutionEngine/GenericValue.h"
     12 #include "llvm/ExecutionEngine/JITEventListener.h"
     13 #include "llvm/ExecutionEngine/JITMemoryManager.h"
     14 #include "llvm/ExecutionEngine/MCJIT.h"
     15 #include "llvm/ExecutionEngine/ObjectBuffer.h"
     16 #include "llvm/ExecutionEngine/ObjectImage.h"
     17 #include "llvm/IR/DataLayout.h"
     18 #include "llvm/IR/DerivedTypes.h"
     19 #include "llvm/IR/Function.h"
     20 #include "llvm/MC/MCAsmInfo.h"
     21 #include "llvm/Support/DynamicLibrary.h"
     22 #include "llvm/Support/ErrorHandling.h"
     23 #include "llvm/Support/MemoryBuffer.h"
     24 #include "llvm/Support/MutexGuard.h"
     25 
     26 using namespace llvm;
     27 
     28 namespace {
     29 
     30 static struct RegisterJIT {
     31   RegisterJIT() { MCJIT::Register(); }
     32 } JITRegistrator;
     33 
     34 }
     35 
     36 extern "C" void LLVMLinkInMCJIT() {
     37 }
     38 
     39 ExecutionEngine *MCJIT::createJIT(Module *M,
     40                                   std::string *ErrorStr,
     41                                   JITMemoryManager *JMM,
     42                                   bool GVsWithCode,
     43                                   TargetMachine *TM) {
     44   // Try to register the program as a source of symbols to resolve against.
     45   //
     46   // FIXME: Don't do this here.
     47   sys::DynamicLibrary::LoadLibraryPermanently(0, NULL);
     48 
     49   return new MCJIT(M, TM, JMM, GVsWithCode);
     50 }
     51 
     52 MCJIT::MCJIT(Module *m, TargetMachine *tm, RTDyldMemoryManager *MM,
     53              bool AllocateGVsWithCode)
     54   : ExecutionEngine(m), TM(tm), Ctx(0), MemMgr(MM), Dyld(MM),
     55     isCompiled(false), M(m)  {
     56 
     57   setDataLayout(TM->getDataLayout());
     58 }
     59 
     60 MCJIT::~MCJIT() {
     61   if (LoadedObject)
     62     NotifyFreeingObject(*LoadedObject.get());
     63   delete MemMgr;
     64   delete TM;
     65 }
     66 
     67 void MCJIT::emitObject(Module *m) {
     68   /// Currently, MCJIT only supports a single module and the module passed to
     69   /// this function call is expected to be the contained module.  The module
     70   /// is passed as a parameter here to prepare for multiple module support in
     71   /// the future.
     72   assert(M == m);
     73 
     74   // Get a thread lock to make sure we aren't trying to compile multiple times
     75   MutexGuard locked(lock);
     76 
     77   // FIXME: Track compilation state on a per-module basis when multiple modules
     78   //        are supported.
     79   // Re-compilation is not supported
     80   if (isCompiled)
     81     return;
     82 
     83   PassManager PM;
     84 
     85   PM.add(new DataLayout(*TM->getDataLayout()));
     86 
     87   // The RuntimeDyld will take ownership of this shortly
     88   OwningPtr<ObjectBufferStream> Buffer(new ObjectBufferStream());
     89 
     90   // Turn the machine code intermediate representation into bytes in memory
     91   // that may be executed.
     92   if (TM->addPassesToEmitMC(PM, Ctx, Buffer->getOStream(), false)) {
     93     report_fatal_error("Target does not support MC emission!");
     94   }
     95 
     96   // Initialize passes.
     97   PM.run(*m);
     98   // Flush the output buffer to get the generated code into memory
     99   Buffer->flush();
    100 
    101   // Load the object into the dynamic linker.
    102   // handing off ownership of the buffer
    103   LoadedObject.reset(Dyld.loadObject(Buffer.take()));
    104   if (!LoadedObject)
    105     report_fatal_error(Dyld.getErrorString());
    106 
    107   // Resolve any relocations.
    108   Dyld.resolveRelocations();
    109 
    110   // FIXME: Make this optional, maybe even move it to a JIT event listener
    111   LoadedObject->registerWithDebugger();
    112 
    113   NotifyObjectEmitted(*LoadedObject);
    114 
    115   // FIXME: Add support for per-module compilation state
    116   isCompiled = true;
    117 }
    118 
    119 // FIXME: Add a parameter to identify which object is being finalized when
    120 // MCJIT supports multiple modules.
    121 // FIXME: Provide a way to separate code emission, relocations and page
    122 // protection in the interface.
    123 void MCJIT::finalizeObject() {
    124   // If the module hasn't been compiled, just do that.
    125   if (!isCompiled) {
    126     // If the call to Dyld.resolveRelocations() is removed from emitObject()
    127     // we'll need to do that here.
    128     emitObject(M);
    129 
    130     // Set page permissions.
    131     MemMgr->applyPermissions();
    132 
    133     return;
    134   }
    135 
    136   // Resolve any relocations.
    137   Dyld.resolveRelocations();
    138 
    139   // Set page permissions.
    140   MemMgr->applyPermissions();
    141 }
    142 
    143 void *MCJIT::getPointerToBasicBlock(BasicBlock *BB) {
    144   report_fatal_error("not yet implemented");
    145 }
    146 
    147 void *MCJIT::getPointerToFunction(Function *F) {
    148   // FIXME: This should really return a uint64_t since it's a pointer in the
    149   // target address space, not our local address space. That's part of the
    150   // ExecutionEngine interface, though. Fix that when the old JIT finally
    151   // dies.
    152 
    153   // FIXME: Add support for per-module compilation state
    154   if (!isCompiled)
    155     emitObject(M);
    156 
    157   if (F->isDeclaration() || F->hasAvailableExternallyLinkage()) {
    158     bool AbortOnFailure = !F->hasExternalWeakLinkage();
    159     void *Addr = getPointerToNamedFunction(F->getName(), AbortOnFailure);
    160     addGlobalMapping(F, Addr);
    161     return Addr;
    162   }
    163 
    164   // FIXME: Should the Dyld be retaining module information? Probably not.
    165   // FIXME: Should we be using the mangler for this? Probably.
    166   //
    167   // This is the accessor for the target address, so make sure to check the
    168   // load address of the symbol, not the local address.
    169   StringRef BaseName = F->getName();
    170   if (BaseName[0] == '\1')
    171     return (void*)Dyld.getSymbolLoadAddress(BaseName.substr(1));
    172   return (void*)Dyld.getSymbolLoadAddress((TM->getMCAsmInfo()->getGlobalPrefix()
    173                                        + BaseName).str());
    174 }
    175 
    176 void *MCJIT::recompileAndRelinkFunction(Function *F) {
    177   report_fatal_error("not yet implemented");
    178 }
    179 
    180 void MCJIT::freeMachineCodeForFunction(Function *F) {
    181   report_fatal_error("not yet implemented");
    182 }
    183 
    184 GenericValue MCJIT::runFunction(Function *F,
    185                                 const std::vector<GenericValue> &ArgValues) {
    186   assert(F && "Function *F was null at entry to run()");
    187 
    188   void *FPtr = getPointerToFunction(F);
    189   assert(FPtr && "Pointer to fn's code was null after getPointerToFunction");
    190   FunctionType *FTy = F->getFunctionType();
    191   Type *RetTy = FTy->getReturnType();
    192 
    193   assert((FTy->getNumParams() == ArgValues.size() ||
    194           (FTy->isVarArg() && FTy->getNumParams() <= ArgValues.size())) &&
    195          "Wrong number of arguments passed into function!");
    196   assert(FTy->getNumParams() == ArgValues.size() &&
    197          "This doesn't support passing arguments through varargs (yet)!");
    198 
    199   // Handle some common cases first.  These cases correspond to common `main'
    200   // prototypes.
    201   if (RetTy->isIntegerTy(32) || RetTy->isVoidTy()) {
    202     switch (ArgValues.size()) {
    203     case 3:
    204       if (FTy->getParamType(0)->isIntegerTy(32) &&
    205           FTy->getParamType(1)->isPointerTy() &&
    206           FTy->getParamType(2)->isPointerTy()) {
    207         int (*PF)(int, char **, const char **) =
    208           (int(*)(int, char **, const char **))(intptr_t)FPtr;
    209 
    210         // Call the function.
    211         GenericValue rv;
    212         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
    213                                  (char **)GVTOP(ArgValues[1]),
    214                                  (const char **)GVTOP(ArgValues[2])));
    215         return rv;
    216       }
    217       break;
    218     case 2:
    219       if (FTy->getParamType(0)->isIntegerTy(32) &&
    220           FTy->getParamType(1)->isPointerTy()) {
    221         int (*PF)(int, char **) = (int(*)(int, char **))(intptr_t)FPtr;
    222 
    223         // Call the function.
    224         GenericValue rv;
    225         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue(),
    226                                  (char **)GVTOP(ArgValues[1])));
    227         return rv;
    228       }
    229       break;
    230     case 1:
    231       if (FTy->getNumParams() == 1 &&
    232           FTy->getParamType(0)->isIntegerTy(32)) {
    233         GenericValue rv;
    234         int (*PF)(int) = (int(*)(int))(intptr_t)FPtr;
    235         rv.IntVal = APInt(32, PF(ArgValues[0].IntVal.getZExtValue()));
    236         return rv;
    237       }
    238       break;
    239     }
    240   }
    241 
    242   // Handle cases where no arguments are passed first.
    243   if (ArgValues.empty()) {
    244     GenericValue rv;
    245     switch (RetTy->getTypeID()) {
    246     default: llvm_unreachable("Unknown return type for function call!");
    247     case Type::IntegerTyID: {
    248       unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
    249       if (BitWidth == 1)
    250         rv.IntVal = APInt(BitWidth, ((bool(*)())(intptr_t)FPtr)());
    251       else if (BitWidth <= 8)
    252         rv.IntVal = APInt(BitWidth, ((char(*)())(intptr_t)FPtr)());
    253       else if (BitWidth <= 16)
    254         rv.IntVal = APInt(BitWidth, ((short(*)())(intptr_t)FPtr)());
    255       else if (BitWidth <= 32)
    256         rv.IntVal = APInt(BitWidth, ((int(*)())(intptr_t)FPtr)());
    257       else if (BitWidth <= 64)
    258         rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
    259       else
    260         llvm_unreachable("Integer types > 64 bits not supported");
    261       return rv;
    262     }
    263     case Type::VoidTyID:
    264       rv.IntVal = APInt(32, ((int(*)())(intptr_t)FPtr)());
    265       return rv;
    266     case Type::FloatTyID:
    267       rv.FloatVal = ((float(*)())(intptr_t)FPtr)();
    268       return rv;
    269     case Type::DoubleTyID:
    270       rv.DoubleVal = ((double(*)())(intptr_t)FPtr)();
    271       return rv;
    272     case Type::X86_FP80TyID:
    273     case Type::FP128TyID:
    274     case Type::PPC_FP128TyID:
    275       llvm_unreachable("long double not supported yet");
    276     case Type::PointerTyID:
    277       return PTOGV(((void*(*)())(intptr_t)FPtr)());
    278     }
    279   }
    280 
    281   llvm_unreachable("Full-featured argument passing not supported yet!");
    282 }
    283 
    284 void *MCJIT::getPointerToNamedFunction(const std::string &Name,
    285                                        bool AbortOnFailure) {
    286   // FIXME: Add support for per-module compilation state
    287   if (!isCompiled)
    288     emitObject(M);
    289 
    290   if (!isSymbolSearchingDisabled() && MemMgr) {
    291     void *ptr = MemMgr->getPointerToNamedFunction(Name, false);
    292     if (ptr)
    293       return ptr;
    294   }
    295 
    296   /// If a LazyFunctionCreator is installed, use it to get/create the function.
    297   if (LazyFunctionCreator)
    298     if (void *RP = LazyFunctionCreator(Name))
    299       return RP;
    300 
    301   if (AbortOnFailure) {
    302     report_fatal_error("Program used external function '"+Name+
    303                        "' which could not be resolved!");
    304   }
    305   return 0;
    306 }
    307 
    308 void MCJIT::RegisterJITEventListener(JITEventListener *L) {
    309   if (L == NULL)
    310     return;
    311   MutexGuard locked(lock);
    312   EventListeners.push_back(L);
    313 }
    314 void MCJIT::UnregisterJITEventListener(JITEventListener *L) {
    315   if (L == NULL)
    316     return;
    317   MutexGuard locked(lock);
    318   SmallVector<JITEventListener*, 2>::reverse_iterator I=
    319       std::find(EventListeners.rbegin(), EventListeners.rend(), L);
    320   if (I != EventListeners.rend()) {
    321     std::swap(*I, EventListeners.back());
    322     EventListeners.pop_back();
    323   }
    324 }
    325 void MCJIT::NotifyObjectEmitted(const ObjectImage& Obj) {
    326   MutexGuard locked(lock);
    327   for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
    328     EventListeners[I]->NotifyObjectEmitted(Obj);
    329   }
    330 }
    331 void MCJIT::NotifyFreeingObject(const ObjectImage& Obj) {
    332   MutexGuard locked(lock);
    333   for (unsigned I = 0, S = EventListeners.size(); I < S; ++I) {
    334     EventListeners[I]->NotifyFreeingObject(Obj);
    335   }
    336 }
    337