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      1 //===-- Function.cpp - Implement the Global object classes ----------------===//
      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 Function class for the VMCore library.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "llvm/Module.h"
     15 #include "llvm/DerivedTypes.h"
     16 #include "llvm/IntrinsicInst.h"
     17 #include "llvm/LLVMContext.h"
     18 #include "llvm/CodeGen/ValueTypes.h"
     19 #include "llvm/Support/CallSite.h"
     20 #include "llvm/Support/InstIterator.h"
     21 #include "llvm/Support/LeakDetector.h"
     22 #include "llvm/Support/ManagedStatic.h"
     23 #include "llvm/Support/StringPool.h"
     24 #include "llvm/Support/RWMutex.h"
     25 #include "llvm/Support/Threading.h"
     26 #include "SymbolTableListTraitsImpl.h"
     27 #include "llvm/ADT/DenseMap.h"
     28 #include "llvm/ADT/STLExtras.h"
     29 #include "llvm/ADT/StringExtras.h"
     30 using namespace llvm;
     31 
     32 // Explicit instantiations of SymbolTableListTraits since some of the methods
     33 // are not in the public header file...
     34 template class llvm::SymbolTableListTraits<Argument, Function>;
     35 template class llvm::SymbolTableListTraits<BasicBlock, Function>;
     36 
     37 //===----------------------------------------------------------------------===//
     38 // Argument Implementation
     39 //===----------------------------------------------------------------------===//
     40 
     41 void Argument::anchor() { }
     42 
     43 Argument::Argument(Type *Ty, const Twine &Name, Function *Par)
     44   : Value(Ty, Value::ArgumentVal) {
     45   Parent = 0;
     46 
     47   // Make sure that we get added to a function
     48   LeakDetector::addGarbageObject(this);
     49 
     50   if (Par)
     51     Par->getArgumentList().push_back(this);
     52   setName(Name);
     53 }
     54 
     55 void Argument::setParent(Function *parent) {
     56   if (getParent())
     57     LeakDetector::addGarbageObject(this);
     58   Parent = parent;
     59   if (getParent())
     60     LeakDetector::removeGarbageObject(this);
     61 }
     62 
     63 /// getArgNo - Return the index of this formal argument in its containing
     64 /// function.  For example in "void foo(int a, float b)" a is 0 and b is 1.
     65 unsigned Argument::getArgNo() const {
     66   const Function *F = getParent();
     67   assert(F && "Argument is not in a function");
     68 
     69   Function::const_arg_iterator AI = F->arg_begin();
     70   unsigned ArgIdx = 0;
     71   for (; &*AI != this; ++AI)
     72     ++ArgIdx;
     73 
     74   return ArgIdx;
     75 }
     76 
     77 /// hasByValAttr - Return true if this argument has the byval attribute on it
     78 /// in its containing function.
     79 bool Argument::hasByValAttr() const {
     80   if (!getType()->isPointerTy()) return false;
     81   return getParent()->paramHasAttr(getArgNo()+1, Attribute::ByVal);
     82 }
     83 
     84 unsigned Argument::getParamAlignment() const {
     85   assert(getType()->isPointerTy() && "Only pointers have alignments");
     86   return getParent()->getParamAlignment(getArgNo()+1);
     87 
     88 }
     89 
     90 /// hasNestAttr - Return true if this argument has the nest attribute on
     91 /// it in its containing function.
     92 bool Argument::hasNestAttr() const {
     93   if (!getType()->isPointerTy()) return false;
     94   return getParent()->paramHasAttr(getArgNo()+1, Attribute::Nest);
     95 }
     96 
     97 /// hasNoAliasAttr - Return true if this argument has the noalias attribute on
     98 /// it in its containing function.
     99 bool Argument::hasNoAliasAttr() const {
    100   if (!getType()->isPointerTy()) return false;
    101   return getParent()->paramHasAttr(getArgNo()+1, Attribute::NoAlias);
    102 }
    103 
    104 /// hasNoCaptureAttr - Return true if this argument has the nocapture attribute
    105 /// on it in its containing function.
    106 bool Argument::hasNoCaptureAttr() const {
    107   if (!getType()->isPointerTy()) return false;
    108   return getParent()->paramHasAttr(getArgNo()+1, Attribute::NoCapture);
    109 }
    110 
    111 /// hasSRetAttr - Return true if this argument has the sret attribute on
    112 /// it in its containing function.
    113 bool Argument::hasStructRetAttr() const {
    114   if (!getType()->isPointerTy()) return false;
    115   if (this != getParent()->arg_begin())
    116     return false; // StructRet param must be first param
    117   return getParent()->paramHasAttr(1, Attribute::StructRet);
    118 }
    119 
    120 /// addAttr - Add a Attribute to an argument
    121 void Argument::addAttr(Attributes attr) {
    122   getParent()->addAttribute(getArgNo() + 1, attr);
    123 }
    124 
    125 /// removeAttr - Remove a Attribute from an argument
    126 void Argument::removeAttr(Attributes attr) {
    127   getParent()->removeAttribute(getArgNo() + 1, attr);
    128 }
    129 
    130 
    131 //===----------------------------------------------------------------------===//
    132 // Helper Methods in Function
    133 //===----------------------------------------------------------------------===//
    134 
    135 LLVMContext &Function::getContext() const {
    136   return getType()->getContext();
    137 }
    138 
    139 FunctionType *Function::getFunctionType() const {
    140   return cast<FunctionType>(getType()->getElementType());
    141 }
    142 
    143 bool Function::isVarArg() const {
    144   return getFunctionType()->isVarArg();
    145 }
    146 
    147 Type *Function::getReturnType() const {
    148   return getFunctionType()->getReturnType();
    149 }
    150 
    151 void Function::removeFromParent() {
    152   getParent()->getFunctionList().remove(this);
    153 }
    154 
    155 void Function::eraseFromParent() {
    156   getParent()->getFunctionList().erase(this);
    157 }
    158 
    159 //===----------------------------------------------------------------------===//
    160 // Function Implementation
    161 //===----------------------------------------------------------------------===//
    162 
    163 Function::Function(FunctionType *Ty, LinkageTypes Linkage,
    164                    const Twine &name, Module *ParentModule)
    165   : GlobalValue(PointerType::getUnqual(Ty),
    166                 Value::FunctionVal, 0, 0, Linkage, name) {
    167   assert(FunctionType::isValidReturnType(getReturnType()) &&
    168          "invalid return type");
    169   SymTab = new ValueSymbolTable();
    170 
    171   // If the function has arguments, mark them as lazily built.
    172   if (Ty->getNumParams())
    173     setValueSubclassData(1);   // Set the "has lazy arguments" bit.
    174 
    175   // Make sure that we get added to a function
    176   LeakDetector::addGarbageObject(this);
    177 
    178   if (ParentModule)
    179     ParentModule->getFunctionList().push_back(this);
    180 
    181   // Ensure intrinsics have the right parameter attributes.
    182   if (unsigned IID = getIntrinsicID())
    183     setAttributes(Intrinsic::getAttributes(Intrinsic::ID(IID)));
    184 
    185 }
    186 
    187 Function::~Function() {
    188   dropAllReferences();    // After this it is safe to delete instructions.
    189 
    190   // Delete all of the method arguments and unlink from symbol table...
    191   ArgumentList.clear();
    192   delete SymTab;
    193 
    194   // Remove the function from the on-the-side GC table.
    195   clearGC();
    196 }
    197 
    198 void Function::BuildLazyArguments() const {
    199   // Create the arguments vector, all arguments start out unnamed.
    200   FunctionType *FT = getFunctionType();
    201   for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
    202     assert(!FT->getParamType(i)->isVoidTy() &&
    203            "Cannot have void typed arguments!");
    204     ArgumentList.push_back(new Argument(FT->getParamType(i)));
    205   }
    206 
    207   // Clear the lazy arguments bit.
    208   unsigned SDC = getSubclassDataFromValue();
    209   const_cast<Function*>(this)->setValueSubclassData(SDC &= ~1);
    210 }
    211 
    212 size_t Function::arg_size() const {
    213   return getFunctionType()->getNumParams();
    214 }
    215 bool Function::arg_empty() const {
    216   return getFunctionType()->getNumParams() == 0;
    217 }
    218 
    219 void Function::setParent(Module *parent) {
    220   if (getParent())
    221     LeakDetector::addGarbageObject(this);
    222   Parent = parent;
    223   if (getParent())
    224     LeakDetector::removeGarbageObject(this);
    225 }
    226 
    227 // dropAllReferences() - This function causes all the subinstructions to "let
    228 // go" of all references that they are maintaining.  This allows one to
    229 // 'delete' a whole class at a time, even though there may be circular
    230 // references... first all references are dropped, and all use counts go to
    231 // zero.  Then everything is deleted for real.  Note that no operations are
    232 // valid on an object that has "dropped all references", except operator
    233 // delete.
    234 //
    235 void Function::dropAllReferences() {
    236   for (iterator I = begin(), E = end(); I != E; ++I)
    237     I->dropAllReferences();
    238 
    239   // Delete all basic blocks. They are now unused, except possibly by
    240   // blockaddresses, but BasicBlock's destructor takes care of those.
    241   while (!BasicBlocks.empty())
    242     BasicBlocks.begin()->eraseFromParent();
    243 }
    244 
    245 void Function::addAttribute(unsigned i, Attributes attr) {
    246   AttrListPtr PAL = getAttributes();
    247   PAL = PAL.addAttr(i, attr);
    248   setAttributes(PAL);
    249 }
    250 
    251 void Function::removeAttribute(unsigned i, Attributes attr) {
    252   AttrListPtr PAL = getAttributes();
    253   PAL = PAL.removeAttr(i, attr);
    254   setAttributes(PAL);
    255 }
    256 
    257 // Maintain the GC name for each function in an on-the-side table. This saves
    258 // allocating an additional word in Function for programs which do not use GC
    259 // (i.e., most programs) at the cost of increased overhead for clients which do
    260 // use GC.
    261 static DenseMap<const Function*,PooledStringPtr> *GCNames;
    262 static StringPool *GCNamePool;
    263 static ManagedStatic<sys::SmartRWMutex<true> > GCLock;
    264 
    265 bool Function::hasGC() const {
    266   sys::SmartScopedReader<true> Reader(*GCLock);
    267   return GCNames && GCNames->count(this);
    268 }
    269 
    270 const char *Function::getGC() const {
    271   assert(hasGC() && "Function has no collector");
    272   sys::SmartScopedReader<true> Reader(*GCLock);
    273   return *(*GCNames)[this];
    274 }
    275 
    276 void Function::setGC(const char *Str) {
    277   sys::SmartScopedWriter<true> Writer(*GCLock);
    278   if (!GCNamePool)
    279     GCNamePool = new StringPool();
    280   if (!GCNames)
    281     GCNames = new DenseMap<const Function*,PooledStringPtr>();
    282   (*GCNames)[this] = GCNamePool->intern(Str);
    283 }
    284 
    285 void Function::clearGC() {
    286   sys::SmartScopedWriter<true> Writer(*GCLock);
    287   if (GCNames) {
    288     GCNames->erase(this);
    289     if (GCNames->empty()) {
    290       delete GCNames;
    291       GCNames = 0;
    292       if (GCNamePool->empty()) {
    293         delete GCNamePool;
    294         GCNamePool = 0;
    295       }
    296     }
    297   }
    298 }
    299 
    300 /// copyAttributesFrom - copy all additional attributes (those not needed to
    301 /// create a Function) from the Function Src to this one.
    302 void Function::copyAttributesFrom(const GlobalValue *Src) {
    303   assert(isa<Function>(Src) && "Expected a Function!");
    304   GlobalValue::copyAttributesFrom(Src);
    305   const Function *SrcF = cast<Function>(Src);
    306   setCallingConv(SrcF->getCallingConv());
    307   setAttributes(SrcF->getAttributes());
    308   if (SrcF->hasGC())
    309     setGC(SrcF->getGC());
    310   else
    311     clearGC();
    312 }
    313 
    314 /// getIntrinsicID - This method returns the ID number of the specified
    315 /// function, or Intrinsic::not_intrinsic if the function is not an
    316 /// intrinsic, or if the pointer is null.  This value is always defined to be
    317 /// zero to allow easy checking for whether a function is intrinsic or not.  The
    318 /// particular intrinsic functions which correspond to this value are defined in
    319 /// llvm/Intrinsics.h.
    320 ///
    321 unsigned Function::getIntrinsicID() const {
    322   const ValueName *ValName = this->getValueName();
    323   if (!ValName)
    324     return 0;
    325   unsigned Len = ValName->getKeyLength();
    326   const char *Name = ValName->getKeyData();
    327 
    328   if (Len < 5 || Name[4] != '.' || Name[0] != 'l' || Name[1] != 'l'
    329       || Name[2] != 'v' || Name[3] != 'm')
    330     return 0;  // All intrinsics start with 'llvm.'
    331 
    332 #define GET_FUNCTION_RECOGNIZER
    333 #include "llvm/Intrinsics.gen"
    334 #undef GET_FUNCTION_RECOGNIZER
    335   return 0;
    336 }
    337 
    338 std::string Intrinsic::getName(ID id, ArrayRef<Type*> Tys) {
    339   assert(id < num_intrinsics && "Invalid intrinsic ID!");
    340   static const char * const Table[] = {
    341     "not_intrinsic",
    342 #define GET_INTRINSIC_NAME_TABLE
    343 #include "llvm/Intrinsics.gen"
    344 #undef GET_INTRINSIC_NAME_TABLE
    345   };
    346   if (Tys.empty())
    347     return Table[id];
    348   std::string Result(Table[id]);
    349   for (unsigned i = 0; i < Tys.size(); ++i) {
    350     if (PointerType* PTyp = dyn_cast<PointerType>(Tys[i])) {
    351       Result += ".p" + llvm::utostr(PTyp->getAddressSpace()) +
    352                 EVT::getEVT(PTyp->getElementType()).getEVTString();
    353     }
    354     else if (Tys[i])
    355       Result += "." + EVT::getEVT(Tys[i]).getEVTString();
    356   }
    357   return Result;
    358 }
    359 
    360 
    361 /// IIT_Info - These are enumerators that describe the entries returned by the
    362 /// getIntrinsicInfoTableEntries function.
    363 ///
    364 /// NOTE: This must be kept in synch with the copy in TblGen/IntrinsicEmitter!
    365 enum IIT_Info {
    366   // Common values should be encoded with 0-15.
    367   IIT_Done = 0,
    368   IIT_I1   = 1,
    369   IIT_I8   = 2,
    370   IIT_I16  = 3,
    371   IIT_I32  = 4,
    372   IIT_I64  = 5,
    373   IIT_F32  = 6,
    374   IIT_F64  = 7,
    375   IIT_V2   = 8,
    376   IIT_V4   = 9,
    377   IIT_V8   = 10,
    378   IIT_V16  = 11,
    379   IIT_V32  = 12,
    380   IIT_MMX  = 13,
    381   IIT_PTR  = 14,
    382   IIT_ARG  = 15,
    383 
    384   // Values from 16+ are only encodable with the inefficient encoding.
    385   IIT_METADATA = 16,
    386   IIT_EMPTYSTRUCT = 17,
    387   IIT_STRUCT2 = 18,
    388   IIT_STRUCT3 = 19,
    389   IIT_STRUCT4 = 20,
    390   IIT_STRUCT5 = 21,
    391   IIT_EXTEND_VEC_ARG = 22,
    392   IIT_TRUNC_VEC_ARG = 23,
    393   IIT_ANYPTR = 24
    394 };
    395 
    396 
    397 static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
    398                       SmallVectorImpl<Intrinsic::IITDescriptor> &OutputTable) {
    399   IIT_Info Info = IIT_Info(Infos[NextElt++]);
    400   unsigned StructElts = 2;
    401   using namespace Intrinsic;
    402 
    403   switch (Info) {
    404   case IIT_Done:
    405     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Void, 0));
    406     return;
    407   case IIT_MMX:
    408     OutputTable.push_back(IITDescriptor::get(IITDescriptor::MMX, 0));
    409     return;
    410   case IIT_METADATA:
    411     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Metadata, 0));
    412     return;
    413   case IIT_F32:
    414     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Float, 0));
    415     return;
    416   case IIT_F64:
    417     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Double, 0));
    418     return;
    419   case IIT_I1:
    420     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 1));
    421     return;
    422   case IIT_I8:
    423     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 8));
    424     return;
    425   case IIT_I16:
    426     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer,16));
    427     return;
    428   case IIT_I32:
    429     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 32));
    430     return;
    431   case IIT_I64:
    432     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 64));
    433     return;
    434   case IIT_V2:
    435     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 2));
    436     DecodeIITType(NextElt, Infos, OutputTable);
    437     return;
    438   case IIT_V4:
    439     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 4));
    440     DecodeIITType(NextElt, Infos, OutputTable);
    441     return;
    442   case IIT_V8:
    443     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 8));
    444     DecodeIITType(NextElt, Infos, OutputTable);
    445     return;
    446   case IIT_V16:
    447     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 16));
    448     DecodeIITType(NextElt, Infos, OutputTable);
    449     return;
    450   case IIT_V32:
    451     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 32));
    452     DecodeIITType(NextElt, Infos, OutputTable);
    453     return;
    454   case IIT_PTR:
    455     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer, 0));
    456     DecodeIITType(NextElt, Infos, OutputTable);
    457     return;
    458   case IIT_ANYPTR: {  // [ANYPTR addrspace, subtype]
    459     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer,
    460                                              Infos[NextElt++]));
    461     DecodeIITType(NextElt, Infos, OutputTable);
    462     return;
    463   }
    464   case IIT_ARG: {
    465     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    466     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Argument, ArgInfo));
    467     return;
    468   }
    469   case IIT_EXTEND_VEC_ARG: {
    470     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    471     OutputTable.push_back(IITDescriptor::get(IITDescriptor::ExtendVecArgument,
    472                                              ArgInfo));
    473     return;
    474   }
    475   case IIT_TRUNC_VEC_ARG: {
    476     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    477     OutputTable.push_back(IITDescriptor::get(IITDescriptor::TruncVecArgument,
    478                                              ArgInfo));
    479     return;
    480   }
    481   case IIT_EMPTYSTRUCT:
    482     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct, 0));
    483     return;
    484   case IIT_STRUCT5: ++StructElts; // FALL THROUGH.
    485   case IIT_STRUCT4: ++StructElts; // FALL THROUGH.
    486   case IIT_STRUCT3: ++StructElts; // FALL THROUGH.
    487   case IIT_STRUCT2: {
    488     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct,StructElts));
    489 
    490     for (unsigned i = 0; i != StructElts; ++i)
    491       DecodeIITType(NextElt, Infos, OutputTable);
    492     return;
    493   }
    494   }
    495   llvm_unreachable("unhandled");
    496 }
    497 
    498 
    499 #define GET_INTRINSIC_GENERATOR_GLOBAL
    500 #include "llvm/Intrinsics.gen"
    501 #undef GET_INTRINSIC_GENERATOR_GLOBAL
    502 
    503 void Intrinsic::getIntrinsicInfoTableEntries(ID id,
    504                                              SmallVectorImpl<IITDescriptor> &T){
    505   // Check to see if the intrinsic's type was expressible by the table.
    506   unsigned TableVal = IIT_Table[id-1];
    507 
    508   // Decode the TableVal into an array of IITValues.
    509   SmallVector<unsigned char, 8> IITValues;
    510   ArrayRef<unsigned char> IITEntries;
    511   unsigned NextElt = 0;
    512   if ((TableVal >> 31) != 0) {
    513     // This is an offset into the IIT_LongEncodingTable.
    514     IITEntries = IIT_LongEncodingTable;
    515 
    516     // Strip sentinel bit.
    517     NextElt = (TableVal << 1) >> 1;
    518   } else {
    519     // Decode the TableVal into an array of IITValues.  If the entry was encoded
    520     // into a single word in the table itself, decode it now.
    521     do {
    522       IITValues.push_back(TableVal & 0xF);
    523       TableVal >>= 4;
    524     } while (TableVal);
    525 
    526     IITEntries = IITValues;
    527     NextElt = 0;
    528   }
    529 
    530   // Okay, decode the table into the output vector of IITDescriptors.
    531   DecodeIITType(NextElt, IITEntries, T);
    532   while (NextElt != IITEntries.size() && IITEntries[NextElt] != 0)
    533     DecodeIITType(NextElt, IITEntries, T);
    534 }
    535 
    536 
    537 static Type *DecodeFixedType(ArrayRef<Intrinsic::IITDescriptor> &Infos,
    538                              ArrayRef<Type*> Tys, LLVMContext &Context) {
    539   using namespace Intrinsic;
    540   IITDescriptor D = Infos.front();
    541   Infos = Infos.slice(1);
    542 
    543   switch (D.Kind) {
    544   case IITDescriptor::Void: return Type::getVoidTy(Context);
    545   case IITDescriptor::MMX: return Type::getX86_MMXTy(Context);
    546   case IITDescriptor::Metadata: return Type::getMetadataTy(Context);
    547   case IITDescriptor::Float: return Type::getFloatTy(Context);
    548   case IITDescriptor::Double: return Type::getDoubleTy(Context);
    549 
    550   case IITDescriptor::Integer:
    551     return IntegerType::get(Context, D.Integer_Width);
    552   case IITDescriptor::Vector:
    553     return VectorType::get(DecodeFixedType(Infos, Tys, Context),D.Vector_Width);
    554   case IITDescriptor::Pointer:
    555     return PointerType::get(DecodeFixedType(Infos, Tys, Context),
    556                             D.Pointer_AddressSpace);
    557   case IITDescriptor::Struct: {
    558     Type *Elts[5];
    559     assert(D.Struct_NumElements <= 5 && "Can't handle this yet");
    560     for (unsigned i = 0, e = D.Struct_NumElements; i != e; ++i)
    561       Elts[i] = DecodeFixedType(Infos, Tys, Context);
    562     return StructType::get(Context, ArrayRef<Type*>(Elts,D.Struct_NumElements));
    563   }
    564 
    565   case IITDescriptor::Argument:
    566     return Tys[D.getArgumentNumber()];
    567   case IITDescriptor::ExtendVecArgument:
    568     return VectorType::getExtendedElementVectorType(cast<VectorType>(
    569                                                   Tys[D.getArgumentNumber()]));
    570 
    571   case IITDescriptor::TruncVecArgument:
    572     return VectorType::getTruncatedElementVectorType(cast<VectorType>(
    573                                                   Tys[D.getArgumentNumber()]));
    574   }
    575   llvm_unreachable("unhandled");
    576 }
    577 
    578 
    579 
    580 FunctionType *Intrinsic::getType(LLVMContext &Context,
    581                                  ID id, ArrayRef<Type*> Tys) {
    582   SmallVector<IITDescriptor, 8> Table;
    583   getIntrinsicInfoTableEntries(id, Table);
    584 
    585   ArrayRef<IITDescriptor> TableRef = Table;
    586   Type *ResultTy = DecodeFixedType(TableRef, Tys, Context);
    587 
    588   SmallVector<Type*, 8> ArgTys;
    589   while (!TableRef.empty())
    590     ArgTys.push_back(DecodeFixedType(TableRef, Tys, Context));
    591 
    592   return FunctionType::get(ResultTy, ArgTys, false);
    593 }
    594 
    595 bool Intrinsic::isOverloaded(ID id) {
    596 #define GET_INTRINSIC_OVERLOAD_TABLE
    597 #include "llvm/Intrinsics.gen"
    598 #undef GET_INTRINSIC_OVERLOAD_TABLE
    599 }
    600 
    601 /// This defines the "Intrinsic::getAttributes(ID id)" method.
    602 #define GET_INTRINSIC_ATTRIBUTES
    603 #include "llvm/Intrinsics.gen"
    604 #undef GET_INTRINSIC_ATTRIBUTES
    605 
    606 Function *Intrinsic::getDeclaration(Module *M, ID id, ArrayRef<Type*> Tys) {
    607   // There can never be multiple globals with the same name of different types,
    608   // because intrinsics must be a specific type.
    609   return
    610     cast<Function>(M->getOrInsertFunction(getName(id, Tys),
    611                                           getType(M->getContext(), id, Tys)));
    612 }
    613 
    614 // This defines the "Intrinsic::getIntrinsicForGCCBuiltin()" method.
    615 #define GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
    616 #include "llvm/Intrinsics.gen"
    617 #undef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
    618 
    619 /// hasAddressTaken - returns true if there are any uses of this function
    620 /// other than direct calls or invokes to it.
    621 bool Function::hasAddressTaken(const User* *PutOffender) const {
    622   for (Value::const_use_iterator I = use_begin(), E = use_end(); I != E; ++I) {
    623     const User *U = *I;
    624     if (isa<BlockAddress>(U))
    625       continue;
    626     if (!isa<CallInst>(U) && !isa<InvokeInst>(U))
    627       return PutOffender ? (*PutOffender = U, true) : true;
    628     ImmutableCallSite CS(cast<Instruction>(U));
    629     if (!CS.isCallee(I))
    630       return PutOffender ? (*PutOffender = U, true) : true;
    631   }
    632   return false;
    633 }
    634 
    635 bool Function::isDefTriviallyDead() const {
    636   // Check the linkage
    637   if (!hasLinkOnceLinkage() && !hasLocalLinkage() &&
    638       !hasAvailableExternallyLinkage())
    639     return false;
    640 
    641   // Check if the function is used by anything other than a blockaddress.
    642   for (Value::const_use_iterator I = use_begin(), E = use_end(); I != E; ++I)
    643     if (!isa<BlockAddress>(*I))
    644       return false;
    645 
    646   return true;
    647 }
    648 
    649 /// callsFunctionThatReturnsTwice - Return true if the function has a call to
    650 /// setjmp or other function that gcc recognizes as "returning twice".
    651 bool Function::callsFunctionThatReturnsTwice() const {
    652   for (const_inst_iterator
    653          I = inst_begin(this), E = inst_end(this); I != E; ++I) {
    654     const CallInst* callInst = dyn_cast<CallInst>(&*I);
    655     if (!callInst)
    656       continue;
    657     if (callInst->canReturnTwice())
    658       return true;
    659   }
    660 
    661   return false;
    662 }
    663 
    664