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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 IR library.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "llvm/IR/Function.h"
     15 #include "LLVMContextImpl.h"
     16 #include "SymbolTableListTraitsImpl.h"
     17 #include "llvm/ADT/DenseMap.h"
     18 #include "llvm/ADT/STLExtras.h"
     19 #include "llvm/ADT/StringExtras.h"
     20 #include "llvm/CodeGen/ValueTypes.h"
     21 #include "llvm/IR/DerivedTypes.h"
     22 #include "llvm/IR/IntrinsicInst.h"
     23 #include "llvm/IR/LLVMContext.h"
     24 #include "llvm/IR/Module.h"
     25 #include "llvm/Support/CallSite.h"
     26 #include "llvm/Support/InstIterator.h"
     27 #include "llvm/Support/LeakDetector.h"
     28 #include "llvm/Support/ManagedStatic.h"
     29 #include "llvm/Support/RWMutex.h"
     30 #include "llvm/Support/StringPool.h"
     31 #include "llvm/Support/Threading.h"
     32 using namespace llvm;
     33 
     34 // Explicit instantiations of SymbolTableListTraits since some of the methods
     35 // are not in the public header file...
     36 template class llvm::SymbolTableListTraits<Argument, Function>;
     37 template class llvm::SymbolTableListTraits<BasicBlock, Function>;
     38 
     39 //===----------------------------------------------------------------------===//
     40 // Argument Implementation
     41 //===----------------------------------------------------------------------===//
     42 
     43 void Argument::anchor() { }
     44 
     45 Argument::Argument(Type *Ty, const Twine &Name, Function *Par)
     46   : Value(Ty, Value::ArgumentVal) {
     47   Parent = 0;
     48 
     49   // Make sure that we get added to a function
     50   LeakDetector::addGarbageObject(this);
     51 
     52   if (Par)
     53     Par->getArgumentList().push_back(this);
     54   setName(Name);
     55 }
     56 
     57 void Argument::setParent(Function *parent) {
     58   if (getParent())
     59     LeakDetector::addGarbageObject(this);
     60   Parent = parent;
     61   if (getParent())
     62     LeakDetector::removeGarbageObject(this);
     63 }
     64 
     65 /// getArgNo - Return the index of this formal argument in its containing
     66 /// function.  For example in "void foo(int a, float b)" a is 0 and b is 1.
     67 unsigned Argument::getArgNo() const {
     68   const Function *F = getParent();
     69   assert(F && "Argument is not in a function");
     70 
     71   Function::const_arg_iterator AI = F->arg_begin();
     72   unsigned ArgIdx = 0;
     73   for (; &*AI != this; ++AI)
     74     ++ArgIdx;
     75 
     76   return ArgIdx;
     77 }
     78 
     79 /// hasByValAttr - Return true if this argument has the byval attribute on it
     80 /// in its containing function.
     81 bool Argument::hasByValAttr() const {
     82   if (!getType()->isPointerTy()) return false;
     83   return getParent()->getAttributes().
     84     hasAttribute(getArgNo()+1, Attribute::ByVal);
     85 }
     86 
     87 unsigned Argument::getParamAlignment() const {
     88   assert(getType()->isPointerTy() && "Only pointers have alignments");
     89   return getParent()->getParamAlignment(getArgNo()+1);
     90 
     91 }
     92 
     93 /// hasNestAttr - Return true if this argument has the nest attribute on
     94 /// it in its containing function.
     95 bool Argument::hasNestAttr() const {
     96   if (!getType()->isPointerTy()) return false;
     97   return getParent()->getAttributes().
     98     hasAttribute(getArgNo()+1, Attribute::Nest);
     99 }
    100 
    101 /// hasNoAliasAttr - Return true if this argument has the noalias attribute on
    102 /// it in its containing function.
    103 bool Argument::hasNoAliasAttr() const {
    104   if (!getType()->isPointerTy()) return false;
    105   return getParent()->getAttributes().
    106     hasAttribute(getArgNo()+1, Attribute::NoAlias);
    107 }
    108 
    109 /// hasNoCaptureAttr - Return true if this argument has the nocapture attribute
    110 /// on it in its containing function.
    111 bool Argument::hasNoCaptureAttr() const {
    112   if (!getType()->isPointerTy()) return false;
    113   return getParent()->getAttributes().
    114     hasAttribute(getArgNo()+1, Attribute::NoCapture);
    115 }
    116 
    117 /// hasSRetAttr - Return true if this argument has the sret attribute on
    118 /// it in its containing function.
    119 bool Argument::hasStructRetAttr() const {
    120   if (!getType()->isPointerTy()) return false;
    121   if (this != getParent()->arg_begin())
    122     return false; // StructRet param must be first param
    123   return getParent()->getAttributes().
    124     hasAttribute(1, Attribute::StructRet);
    125 }
    126 
    127 /// addAttr - Add attributes to an argument.
    128 void Argument::addAttr(AttributeSet AS) {
    129   assert(AS.getNumSlots() <= 1 &&
    130          "Trying to add more than one attribute set to an argument!");
    131   AttrBuilder B(AS, AS.getSlotIndex(0));
    132   getParent()->addAttributes(getArgNo() + 1,
    133                              AttributeSet::get(Parent->getContext(),
    134                                                getArgNo() + 1, B));
    135 }
    136 
    137 /// removeAttr - Remove attributes from an argument.
    138 void Argument::removeAttr(AttributeSet AS) {
    139   assert(AS.getNumSlots() <= 1 &&
    140          "Trying to remove more than one attribute set from an argument!");
    141   AttrBuilder B(AS, AS.getSlotIndex(0));
    142   getParent()->removeAttributes(getArgNo() + 1,
    143                                 AttributeSet::get(Parent->getContext(),
    144                                                   getArgNo() + 1, B));
    145 }
    146 
    147 //===----------------------------------------------------------------------===//
    148 // Helper Methods in Function
    149 //===----------------------------------------------------------------------===//
    150 
    151 LLVMContext &Function::getContext() const {
    152   return getType()->getContext();
    153 }
    154 
    155 FunctionType *Function::getFunctionType() const {
    156   return cast<FunctionType>(getType()->getElementType());
    157 }
    158 
    159 bool Function::isVarArg() const {
    160   return getFunctionType()->isVarArg();
    161 }
    162 
    163 Type *Function::getReturnType() const {
    164   return getFunctionType()->getReturnType();
    165 }
    166 
    167 void Function::removeFromParent() {
    168   getParent()->getFunctionList().remove(this);
    169 }
    170 
    171 void Function::eraseFromParent() {
    172   getParent()->getFunctionList().erase(this);
    173 }
    174 
    175 //===----------------------------------------------------------------------===//
    176 // Function Implementation
    177 //===----------------------------------------------------------------------===//
    178 
    179 Function::Function(FunctionType *Ty, LinkageTypes Linkage,
    180                    const Twine &name, Module *ParentModule)
    181   : GlobalValue(PointerType::getUnqual(Ty),
    182                 Value::FunctionVal, 0, 0, Linkage, name) {
    183   assert(FunctionType::isValidReturnType(getReturnType()) &&
    184          "invalid return type");
    185   SymTab = new ValueSymbolTable();
    186 
    187   // If the function has arguments, mark them as lazily built.
    188   if (Ty->getNumParams())
    189     setValueSubclassData(1);   // Set the "has lazy arguments" bit.
    190 
    191   // Make sure that we get added to a function
    192   LeakDetector::addGarbageObject(this);
    193 
    194   if (ParentModule)
    195     ParentModule->getFunctionList().push_back(this);
    196 
    197   // Ensure intrinsics have the right parameter attributes.
    198   if (unsigned IID = getIntrinsicID())
    199     setAttributes(Intrinsic::getAttributes(getContext(), Intrinsic::ID(IID)));
    200 
    201 }
    202 
    203 Function::~Function() {
    204   dropAllReferences();    // After this it is safe to delete instructions.
    205 
    206   // Delete all of the method arguments and unlink from symbol table...
    207   ArgumentList.clear();
    208   delete SymTab;
    209 
    210   // Remove the function from the on-the-side GC table.
    211   clearGC();
    212 
    213   // Remove the intrinsicID from the Cache.
    214   if(getValueName() && isIntrinsic())
    215     getContext().pImpl->IntrinsicIDCache.erase(this);
    216 }
    217 
    218 void Function::BuildLazyArguments() const {
    219   // Create the arguments vector, all arguments start out unnamed.
    220   FunctionType *FT = getFunctionType();
    221   for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
    222     assert(!FT->getParamType(i)->isVoidTy() &&
    223            "Cannot have void typed arguments!");
    224     ArgumentList.push_back(new Argument(FT->getParamType(i)));
    225   }
    226 
    227   // Clear the lazy arguments bit.
    228   unsigned SDC = getSubclassDataFromValue();
    229   const_cast<Function*>(this)->setValueSubclassData(SDC &= ~1);
    230 }
    231 
    232 size_t Function::arg_size() const {
    233   return getFunctionType()->getNumParams();
    234 }
    235 bool Function::arg_empty() const {
    236   return getFunctionType()->getNumParams() == 0;
    237 }
    238 
    239 void Function::setParent(Module *parent) {
    240   if (getParent())
    241     LeakDetector::addGarbageObject(this);
    242   Parent = parent;
    243   if (getParent())
    244     LeakDetector::removeGarbageObject(this);
    245 }
    246 
    247 // dropAllReferences() - This function causes all the subinstructions to "let
    248 // go" of all references that they are maintaining.  This allows one to
    249 // 'delete' a whole class at a time, even though there may be circular
    250 // references... first all references are dropped, and all use counts go to
    251 // zero.  Then everything is deleted for real.  Note that no operations are
    252 // valid on an object that has "dropped all references", except operator
    253 // delete.
    254 //
    255 void Function::dropAllReferences() {
    256   for (iterator I = begin(), E = end(); I != E; ++I)
    257     I->dropAllReferences();
    258 
    259   // Delete all basic blocks. They are now unused, except possibly by
    260   // blockaddresses, but BasicBlock's destructor takes care of those.
    261   while (!BasicBlocks.empty())
    262     BasicBlocks.begin()->eraseFromParent();
    263 }
    264 
    265 void Function::addAttribute(unsigned i, Attribute::AttrKind attr) {
    266   AttributeSet PAL = getAttributes();
    267   PAL = PAL.addAttribute(getContext(), i, attr);
    268   setAttributes(PAL);
    269 }
    270 
    271 void Function::addAttributes(unsigned i, AttributeSet attrs) {
    272   AttributeSet PAL = getAttributes();
    273   PAL = PAL.addAttributes(getContext(), i, attrs);
    274   setAttributes(PAL);
    275 }
    276 
    277 void Function::removeAttributes(unsigned i, AttributeSet attrs) {
    278   AttributeSet PAL = getAttributes();
    279   PAL = PAL.removeAttributes(getContext(), i, attrs);
    280   setAttributes(PAL);
    281 }
    282 
    283 // Maintain the GC name for each function in an on-the-side table. This saves
    284 // allocating an additional word in Function for programs which do not use GC
    285 // (i.e., most programs) at the cost of increased overhead for clients which do
    286 // use GC.
    287 static DenseMap<const Function*,PooledStringPtr> *GCNames;
    288 static StringPool *GCNamePool;
    289 static ManagedStatic<sys::SmartRWMutex<true> > GCLock;
    290 
    291 bool Function::hasGC() const {
    292   sys::SmartScopedReader<true> Reader(*GCLock);
    293   return GCNames && GCNames->count(this);
    294 }
    295 
    296 const char *Function::getGC() const {
    297   assert(hasGC() && "Function has no collector");
    298   sys::SmartScopedReader<true> Reader(*GCLock);
    299   return *(*GCNames)[this];
    300 }
    301 
    302 void Function::setGC(const char *Str) {
    303   sys::SmartScopedWriter<true> Writer(*GCLock);
    304   if (!GCNamePool)
    305     GCNamePool = new StringPool();
    306   if (!GCNames)
    307     GCNames = new DenseMap<const Function*,PooledStringPtr>();
    308   (*GCNames)[this] = GCNamePool->intern(Str);
    309 }
    310 
    311 void Function::clearGC() {
    312   sys::SmartScopedWriter<true> Writer(*GCLock);
    313   if (GCNames) {
    314     GCNames->erase(this);
    315     if (GCNames->empty()) {
    316       delete GCNames;
    317       GCNames = 0;
    318       if (GCNamePool->empty()) {
    319         delete GCNamePool;
    320         GCNamePool = 0;
    321       }
    322     }
    323   }
    324 }
    325 
    326 /// copyAttributesFrom - copy all additional attributes (those not needed to
    327 /// create a Function) from the Function Src to this one.
    328 void Function::copyAttributesFrom(const GlobalValue *Src) {
    329   assert(isa<Function>(Src) && "Expected a Function!");
    330   GlobalValue::copyAttributesFrom(Src);
    331   const Function *SrcF = cast<Function>(Src);
    332   setCallingConv(SrcF->getCallingConv());
    333   setAttributes(SrcF->getAttributes());
    334   if (SrcF->hasGC())
    335     setGC(SrcF->getGC());
    336   else
    337     clearGC();
    338 }
    339 
    340 /// getIntrinsicID - This method returns the ID number of the specified
    341 /// function, or Intrinsic::not_intrinsic if the function is not an
    342 /// intrinsic, or if the pointer is null.  This value is always defined to be
    343 /// zero to allow easy checking for whether a function is intrinsic or not.  The
    344 /// particular intrinsic functions which correspond to this value are defined in
    345 /// llvm/Intrinsics.h.  Results are cached in the LLVM context, subsequent
    346 /// requests for the same ID return results much faster from the cache.
    347 ///
    348 unsigned Function::getIntrinsicID() const {
    349   const ValueName *ValName = this->getValueName();
    350   if (!ValName || !isIntrinsic())
    351     return 0;
    352 
    353   LLVMContextImpl::IntrinsicIDCacheTy &IntrinsicIDCache =
    354     getContext().pImpl->IntrinsicIDCache;
    355   if(!IntrinsicIDCache.count(this)) {
    356     unsigned Id = lookupIntrinsicID();
    357     IntrinsicIDCache[this]=Id;
    358     return Id;
    359   }
    360   return IntrinsicIDCache[this];
    361 }
    362 
    363 /// This private method does the actual lookup of an intrinsic ID when the query
    364 /// could not be answered from the cache.
    365 unsigned Function::lookupIntrinsicID() const {
    366   const ValueName *ValName = this->getValueName();
    367   unsigned Len = ValName->getKeyLength();
    368   const char *Name = ValName->getKeyData();
    369 
    370 #define GET_FUNCTION_RECOGNIZER
    371 #include "llvm/IR/Intrinsics.gen"
    372 #undef GET_FUNCTION_RECOGNIZER
    373 
    374   return 0;
    375 }
    376 
    377 std::string Intrinsic::getName(ID id, ArrayRef<Type*> Tys) {
    378   assert(id < num_intrinsics && "Invalid intrinsic ID!");
    379   static const char * const Table[] = {
    380     "not_intrinsic",
    381 #define GET_INTRINSIC_NAME_TABLE
    382 #include "llvm/IR/Intrinsics.gen"
    383 #undef GET_INTRINSIC_NAME_TABLE
    384   };
    385   if (Tys.empty())
    386     return Table[id];
    387   std::string Result(Table[id]);
    388   for (unsigned i = 0; i < Tys.size(); ++i) {
    389     if (PointerType* PTyp = dyn_cast<PointerType>(Tys[i])) {
    390       Result += ".p" + llvm::utostr(PTyp->getAddressSpace()) +
    391                 EVT::getEVT(PTyp->getElementType()).getEVTString();
    392     }
    393     else if (Tys[i])
    394       Result += "." + EVT::getEVT(Tys[i]).getEVTString();
    395   }
    396   return Result;
    397 }
    398 
    399 
    400 /// IIT_Info - These are enumerators that describe the entries returned by the
    401 /// getIntrinsicInfoTableEntries function.
    402 ///
    403 /// NOTE: This must be kept in synch with the copy in TblGen/IntrinsicEmitter!
    404 enum IIT_Info {
    405   // Common values should be encoded with 0-15.
    406   IIT_Done = 0,
    407   IIT_I1   = 1,
    408   IIT_I8   = 2,
    409   IIT_I16  = 3,
    410   IIT_I32  = 4,
    411   IIT_I64  = 5,
    412   IIT_F16  = 6,
    413   IIT_F32  = 7,
    414   IIT_F64  = 8,
    415   IIT_V2   = 9,
    416   IIT_V4   = 10,
    417   IIT_V8   = 11,
    418   IIT_V16  = 12,
    419   IIT_V32  = 13,
    420   IIT_PTR  = 14,
    421   IIT_ARG  = 15,
    422 
    423   // Values from 16+ are only encodable with the inefficient encoding.
    424   IIT_MMX  = 16,
    425   IIT_METADATA = 17,
    426   IIT_EMPTYSTRUCT = 18,
    427   IIT_STRUCT2 = 19,
    428   IIT_STRUCT3 = 20,
    429   IIT_STRUCT4 = 21,
    430   IIT_STRUCT5 = 22,
    431   IIT_EXTEND_VEC_ARG = 23,
    432   IIT_TRUNC_VEC_ARG = 24,
    433   IIT_ANYPTR = 25
    434 };
    435 
    436 
    437 static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
    438                       SmallVectorImpl<Intrinsic::IITDescriptor> &OutputTable) {
    439   IIT_Info Info = IIT_Info(Infos[NextElt++]);
    440   unsigned StructElts = 2;
    441   using namespace Intrinsic;
    442 
    443   switch (Info) {
    444   case IIT_Done:
    445     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Void, 0));
    446     return;
    447   case IIT_MMX:
    448     OutputTable.push_back(IITDescriptor::get(IITDescriptor::MMX, 0));
    449     return;
    450   case IIT_METADATA:
    451     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Metadata, 0));
    452     return;
    453   case IIT_F16:
    454     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Half, 0));
    455     return;
    456   case IIT_F32:
    457     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Float, 0));
    458     return;
    459   case IIT_F64:
    460     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Double, 0));
    461     return;
    462   case IIT_I1:
    463     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 1));
    464     return;
    465   case IIT_I8:
    466     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 8));
    467     return;
    468   case IIT_I16:
    469     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer,16));
    470     return;
    471   case IIT_I32:
    472     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 32));
    473     return;
    474   case IIT_I64:
    475     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 64));
    476     return;
    477   case IIT_V2:
    478     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 2));
    479     DecodeIITType(NextElt, Infos, OutputTable);
    480     return;
    481   case IIT_V4:
    482     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 4));
    483     DecodeIITType(NextElt, Infos, OutputTable);
    484     return;
    485   case IIT_V8:
    486     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 8));
    487     DecodeIITType(NextElt, Infos, OutputTable);
    488     return;
    489   case IIT_V16:
    490     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 16));
    491     DecodeIITType(NextElt, Infos, OutputTable);
    492     return;
    493   case IIT_V32:
    494     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 32));
    495     DecodeIITType(NextElt, Infos, OutputTable);
    496     return;
    497   case IIT_PTR:
    498     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer, 0));
    499     DecodeIITType(NextElt, Infos, OutputTable);
    500     return;
    501   case IIT_ANYPTR: {  // [ANYPTR addrspace, subtype]
    502     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer,
    503                                              Infos[NextElt++]));
    504     DecodeIITType(NextElt, Infos, OutputTable);
    505     return;
    506   }
    507   case IIT_ARG: {
    508     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    509     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Argument, ArgInfo));
    510     return;
    511   }
    512   case IIT_EXTEND_VEC_ARG: {
    513     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    514     OutputTable.push_back(IITDescriptor::get(IITDescriptor::ExtendVecArgument,
    515                                              ArgInfo));
    516     return;
    517   }
    518   case IIT_TRUNC_VEC_ARG: {
    519     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    520     OutputTable.push_back(IITDescriptor::get(IITDescriptor::TruncVecArgument,
    521                                              ArgInfo));
    522     return;
    523   }
    524   case IIT_EMPTYSTRUCT:
    525     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct, 0));
    526     return;
    527   case IIT_STRUCT5: ++StructElts; // FALL THROUGH.
    528   case IIT_STRUCT4: ++StructElts; // FALL THROUGH.
    529   case IIT_STRUCT3: ++StructElts; // FALL THROUGH.
    530   case IIT_STRUCT2: {
    531     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct,StructElts));
    532 
    533     for (unsigned i = 0; i != StructElts; ++i)
    534       DecodeIITType(NextElt, Infos, OutputTable);
    535     return;
    536   }
    537   }
    538   llvm_unreachable("unhandled");
    539 }
    540 
    541 
    542 #define GET_INTRINSIC_GENERATOR_GLOBAL
    543 #include "llvm/IR/Intrinsics.gen"
    544 #undef GET_INTRINSIC_GENERATOR_GLOBAL
    545 
    546 void Intrinsic::getIntrinsicInfoTableEntries(ID id,
    547                                              SmallVectorImpl<IITDescriptor> &T){
    548   // Check to see if the intrinsic's type was expressible by the table.
    549   unsigned TableVal = IIT_Table[id-1];
    550 
    551   // Decode the TableVal into an array of IITValues.
    552   SmallVector<unsigned char, 8> IITValues;
    553   ArrayRef<unsigned char> IITEntries;
    554   unsigned NextElt = 0;
    555   if ((TableVal >> 31) != 0) {
    556     // This is an offset into the IIT_LongEncodingTable.
    557     IITEntries = IIT_LongEncodingTable;
    558 
    559     // Strip sentinel bit.
    560     NextElt = (TableVal << 1) >> 1;
    561   } else {
    562     // Decode the TableVal into an array of IITValues.  If the entry was encoded
    563     // into a single word in the table itself, decode it now.
    564     do {
    565       IITValues.push_back(TableVal & 0xF);
    566       TableVal >>= 4;
    567     } while (TableVal);
    568 
    569     IITEntries = IITValues;
    570     NextElt = 0;
    571   }
    572 
    573   // Okay, decode the table into the output vector of IITDescriptors.
    574   DecodeIITType(NextElt, IITEntries, T);
    575   while (NextElt != IITEntries.size() && IITEntries[NextElt] != 0)
    576     DecodeIITType(NextElt, IITEntries, T);
    577 }
    578 
    579 
    580 static Type *DecodeFixedType(ArrayRef<Intrinsic::IITDescriptor> &Infos,
    581                              ArrayRef<Type*> Tys, LLVMContext &Context) {
    582   using namespace Intrinsic;
    583   IITDescriptor D = Infos.front();
    584   Infos = Infos.slice(1);
    585 
    586   switch (D.Kind) {
    587   case IITDescriptor::Void: return Type::getVoidTy(Context);
    588   case IITDescriptor::MMX: return Type::getX86_MMXTy(Context);
    589   case IITDescriptor::Metadata: return Type::getMetadataTy(Context);
    590   case IITDescriptor::Half: return Type::getHalfTy(Context);
    591   case IITDescriptor::Float: return Type::getFloatTy(Context);
    592   case IITDescriptor::Double: return Type::getDoubleTy(Context);
    593 
    594   case IITDescriptor::Integer:
    595     return IntegerType::get(Context, D.Integer_Width);
    596   case IITDescriptor::Vector:
    597     return VectorType::get(DecodeFixedType(Infos, Tys, Context),D.Vector_Width);
    598   case IITDescriptor::Pointer:
    599     return PointerType::get(DecodeFixedType(Infos, Tys, Context),
    600                             D.Pointer_AddressSpace);
    601   case IITDescriptor::Struct: {
    602     Type *Elts[5];
    603     assert(D.Struct_NumElements <= 5 && "Can't handle this yet");
    604     for (unsigned i = 0, e = D.Struct_NumElements; i != e; ++i)
    605       Elts[i] = DecodeFixedType(Infos, Tys, Context);
    606     return StructType::get(Context, ArrayRef<Type*>(Elts,D.Struct_NumElements));
    607   }
    608 
    609   case IITDescriptor::Argument:
    610     return Tys[D.getArgumentNumber()];
    611   case IITDescriptor::ExtendVecArgument:
    612     return VectorType::getExtendedElementVectorType(cast<VectorType>(
    613                                                   Tys[D.getArgumentNumber()]));
    614 
    615   case IITDescriptor::TruncVecArgument:
    616     return VectorType::getTruncatedElementVectorType(cast<VectorType>(
    617                                                   Tys[D.getArgumentNumber()]));
    618   }
    619   llvm_unreachable("unhandled");
    620 }
    621 
    622 
    623 
    624 FunctionType *Intrinsic::getType(LLVMContext &Context,
    625                                  ID id, ArrayRef<Type*> Tys) {
    626   SmallVector<IITDescriptor, 8> Table;
    627   getIntrinsicInfoTableEntries(id, Table);
    628 
    629   ArrayRef<IITDescriptor> TableRef = Table;
    630   Type *ResultTy = DecodeFixedType(TableRef, Tys, Context);
    631 
    632   SmallVector<Type*, 8> ArgTys;
    633   while (!TableRef.empty())
    634     ArgTys.push_back(DecodeFixedType(TableRef, Tys, Context));
    635 
    636   return FunctionType::get(ResultTy, ArgTys, false);
    637 }
    638 
    639 bool Intrinsic::isOverloaded(ID id) {
    640 #define GET_INTRINSIC_OVERLOAD_TABLE
    641 #include "llvm/IR/Intrinsics.gen"
    642 #undef GET_INTRINSIC_OVERLOAD_TABLE
    643 }
    644 
    645 /// This defines the "Intrinsic::getAttributes(ID id)" method.
    646 #define GET_INTRINSIC_ATTRIBUTES
    647 #include "llvm/IR/Intrinsics.gen"
    648 #undef GET_INTRINSIC_ATTRIBUTES
    649 
    650 Function *Intrinsic::getDeclaration(Module *M, ID id, ArrayRef<Type*> Tys) {
    651   // There can never be multiple globals with the same name of different types,
    652   // because intrinsics must be a specific type.
    653   return
    654     cast<Function>(M->getOrInsertFunction(getName(id, Tys),
    655                                           getType(M->getContext(), id, Tys)));
    656 }
    657 
    658 // This defines the "Intrinsic::getIntrinsicForGCCBuiltin()" method.
    659 #define GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
    660 #include "llvm/IR/Intrinsics.gen"
    661 #undef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
    662 
    663 /// hasAddressTaken - returns true if there are any uses of this function
    664 /// other than direct calls or invokes to it.
    665 bool Function::hasAddressTaken(const User* *PutOffender) const {
    666   for (Value::const_use_iterator I = use_begin(), E = use_end(); I != E; ++I) {
    667     const User *U = *I;
    668     if (isa<BlockAddress>(U))
    669       continue;
    670     if (!isa<CallInst>(U) && !isa<InvokeInst>(U))
    671       return PutOffender ? (*PutOffender = U, true) : true;
    672     ImmutableCallSite CS(cast<Instruction>(U));
    673     if (!CS.isCallee(I))
    674       return PutOffender ? (*PutOffender = U, true) : true;
    675   }
    676   return false;
    677 }
    678 
    679 bool Function::isDefTriviallyDead() const {
    680   // Check the linkage
    681   if (!hasLinkOnceLinkage() && !hasLocalLinkage() &&
    682       !hasAvailableExternallyLinkage())
    683     return false;
    684 
    685   // Check if the function is used by anything other than a blockaddress.
    686   for (Value::const_use_iterator I = use_begin(), E = use_end(); I != E; ++I)
    687     if (!isa<BlockAddress>(*I))
    688       return false;
    689 
    690   return true;
    691 }
    692 
    693 /// callsFunctionThatReturnsTwice - Return true if the function has a call to
    694 /// setjmp or other function that gcc recognizes as "returning twice".
    695 bool Function::callsFunctionThatReturnsTwice() const {
    696   for (const_inst_iterator
    697          I = inst_begin(this), E = inst_end(this); I != E; ++I) {
    698     const CallInst* callInst = dyn_cast<CallInst>(&*I);
    699     if (!callInst)
    700       continue;
    701     if (callInst->canReturnTwice())
    702       return true;
    703   }
    704 
    705   return false;
    706 }
    707 
    708