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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/CallSite.h"
     22 #include "llvm/IR/Constants.h"
     23 #include "llvm/IR/DerivedTypes.h"
     24 #include "llvm/IR/InstIterator.h"
     25 #include "llvm/IR/IntrinsicInst.h"
     26 #include "llvm/IR/LLVMContext.h"
     27 #include "llvm/IR/MDBuilder.h"
     28 #include "llvm/IR/Metadata.h"
     29 #include "llvm/IR/Module.h"
     30 #include "llvm/Support/ManagedStatic.h"
     31 #include "llvm/Support/RWMutex.h"
     32 #include "llvm/Support/StringPool.h"
     33 #include "llvm/Support/Threading.h"
     34 using namespace llvm;
     35 
     36 // Explicit instantiations of SymbolTableListTraits since some of the methods
     37 // are not in the public header file...
     38 template class llvm::SymbolTableListTraits<Argument>;
     39 template class llvm::SymbolTableListTraits<BasicBlock>;
     40 
     41 //===----------------------------------------------------------------------===//
     42 // Argument Implementation
     43 //===----------------------------------------------------------------------===//
     44 
     45 void Argument::anchor() { }
     46 
     47 Argument::Argument(Type *Ty, const Twine &Name, Function *Par)
     48   : Value(Ty, Value::ArgumentVal) {
     49   Parent = nullptr;
     50 
     51   if (Par)
     52     Par->getArgumentList().push_back(this);
     53   setName(Name);
     54 }
     55 
     56 void Argument::setParent(Function *parent) {
     57   Parent = parent;
     58 }
     59 
     60 /// getArgNo - Return the index of this formal argument in its containing
     61 /// function.  For example in "void foo(int a, float b)" a is 0 and b is 1.
     62 unsigned Argument::getArgNo() const {
     63   const Function *F = getParent();
     64   assert(F && "Argument is not in a function");
     65 
     66   Function::const_arg_iterator AI = F->arg_begin();
     67   unsigned ArgIdx = 0;
     68   for (; &*AI != this; ++AI)
     69     ++ArgIdx;
     70 
     71   return ArgIdx;
     72 }
     73 
     74 /// hasNonNullAttr - Return true if this argument has the nonnull attribute on
     75 /// it in its containing function. Also returns true if at least one byte is
     76 /// known to be dereferenceable and the pointer is in addrspace(0).
     77 bool Argument::hasNonNullAttr() const {
     78   if (!getType()->isPointerTy()) return false;
     79   if (getParent()->getAttributes().
     80         hasAttribute(getArgNo()+1, Attribute::NonNull))
     81     return true;
     82   else if (getDereferenceableBytes() > 0 &&
     83            getType()->getPointerAddressSpace() == 0)
     84     return true;
     85   return false;
     86 }
     87 
     88 /// hasByValAttr - Return true if this argument has the byval attribute on it
     89 /// in its containing function.
     90 bool Argument::hasByValAttr() const {
     91   if (!getType()->isPointerTy()) return false;
     92   return getParent()->getAttributes().
     93     hasAttribute(getArgNo()+1, Attribute::ByVal);
     94 }
     95 
     96 /// \brief Return true if this argument has the inalloca attribute on it in
     97 /// its containing function.
     98 bool Argument::hasInAllocaAttr() const {
     99   if (!getType()->isPointerTy()) return false;
    100   return getParent()->getAttributes().
    101     hasAttribute(getArgNo()+1, Attribute::InAlloca);
    102 }
    103 
    104 bool Argument::hasByValOrInAllocaAttr() const {
    105   if (!getType()->isPointerTy()) return false;
    106   AttributeSet Attrs = getParent()->getAttributes();
    107   return Attrs.hasAttribute(getArgNo() + 1, Attribute::ByVal) ||
    108          Attrs.hasAttribute(getArgNo() + 1, Attribute::InAlloca);
    109 }
    110 
    111 unsigned Argument::getParamAlignment() const {
    112   assert(getType()->isPointerTy() && "Only pointers have alignments");
    113   return getParent()->getParamAlignment(getArgNo()+1);
    114 
    115 }
    116 
    117 uint64_t Argument::getDereferenceableBytes() const {
    118   assert(getType()->isPointerTy() &&
    119          "Only pointers have dereferenceable bytes");
    120   return getParent()->getDereferenceableBytes(getArgNo()+1);
    121 }
    122 
    123 uint64_t Argument::getDereferenceableOrNullBytes() const {
    124   assert(getType()->isPointerTy() &&
    125          "Only pointers have dereferenceable bytes");
    126   return getParent()->getDereferenceableOrNullBytes(getArgNo()+1);
    127 }
    128 
    129 /// hasNestAttr - Return true if this argument has the nest attribute on
    130 /// it in its containing function.
    131 bool Argument::hasNestAttr() const {
    132   if (!getType()->isPointerTy()) return false;
    133   return getParent()->getAttributes().
    134     hasAttribute(getArgNo()+1, Attribute::Nest);
    135 }
    136 
    137 /// hasNoAliasAttr - Return true if this argument has the noalias attribute on
    138 /// it in its containing function.
    139 bool Argument::hasNoAliasAttr() const {
    140   if (!getType()->isPointerTy()) return false;
    141   return getParent()->getAttributes().
    142     hasAttribute(getArgNo()+1, Attribute::NoAlias);
    143 }
    144 
    145 /// hasNoCaptureAttr - Return true if this argument has the nocapture attribute
    146 /// on it in its containing function.
    147 bool Argument::hasNoCaptureAttr() const {
    148   if (!getType()->isPointerTy()) return false;
    149   return getParent()->getAttributes().
    150     hasAttribute(getArgNo()+1, Attribute::NoCapture);
    151 }
    152 
    153 /// hasSRetAttr - Return true if this argument has the sret attribute on
    154 /// it in its containing function.
    155 bool Argument::hasStructRetAttr() const {
    156   if (!getType()->isPointerTy()) return false;
    157   return getParent()->getAttributes().
    158     hasAttribute(getArgNo()+1, Attribute::StructRet);
    159 }
    160 
    161 /// hasReturnedAttr - Return true if this argument has the returned attribute on
    162 /// it in its containing function.
    163 bool Argument::hasReturnedAttr() const {
    164   return getParent()->getAttributes().
    165     hasAttribute(getArgNo()+1, Attribute::Returned);
    166 }
    167 
    168 /// hasZExtAttr - Return true if this argument has the zext attribute on it in
    169 /// its containing function.
    170 bool Argument::hasZExtAttr() const {
    171   return getParent()->getAttributes().
    172     hasAttribute(getArgNo()+1, Attribute::ZExt);
    173 }
    174 
    175 /// hasSExtAttr Return true if this argument has the sext attribute on it in its
    176 /// containing function.
    177 bool Argument::hasSExtAttr() const {
    178   return getParent()->getAttributes().
    179     hasAttribute(getArgNo()+1, Attribute::SExt);
    180 }
    181 
    182 /// Return true if this argument has the readonly or readnone attribute on it
    183 /// in its containing function.
    184 bool Argument::onlyReadsMemory() const {
    185   return getParent()->getAttributes().
    186       hasAttribute(getArgNo()+1, Attribute::ReadOnly) ||
    187       getParent()->getAttributes().
    188       hasAttribute(getArgNo()+1, Attribute::ReadNone);
    189 }
    190 
    191 /// addAttr - Add attributes to an argument.
    192 void Argument::addAttr(AttributeSet AS) {
    193   assert(AS.getNumSlots() <= 1 &&
    194          "Trying to add more than one attribute set to an argument!");
    195   AttrBuilder B(AS, AS.getSlotIndex(0));
    196   getParent()->addAttributes(getArgNo() + 1,
    197                              AttributeSet::get(Parent->getContext(),
    198                                                getArgNo() + 1, B));
    199 }
    200 
    201 /// removeAttr - Remove attributes from an argument.
    202 void Argument::removeAttr(AttributeSet AS) {
    203   assert(AS.getNumSlots() <= 1 &&
    204          "Trying to remove more than one attribute set from an argument!");
    205   AttrBuilder B(AS, AS.getSlotIndex(0));
    206   getParent()->removeAttributes(getArgNo() + 1,
    207                                 AttributeSet::get(Parent->getContext(),
    208                                                   getArgNo() + 1, B));
    209 }
    210 
    211 //===----------------------------------------------------------------------===//
    212 // Helper Methods in Function
    213 //===----------------------------------------------------------------------===//
    214 
    215 bool Function::isMaterializable() const {
    216   return getGlobalObjectSubClassData() & IsMaterializableBit;
    217 }
    218 
    219 void Function::setIsMaterializable(bool V) {
    220   setGlobalObjectBit(IsMaterializableBit, V);
    221 }
    222 
    223 LLVMContext &Function::getContext() const {
    224   return getType()->getContext();
    225 }
    226 
    227 FunctionType *Function::getFunctionType() const { return Ty; }
    228 
    229 bool Function::isVarArg() const {
    230   return getFunctionType()->isVarArg();
    231 }
    232 
    233 Type *Function::getReturnType() const {
    234   return getFunctionType()->getReturnType();
    235 }
    236 
    237 void Function::removeFromParent() {
    238   getParent()->getFunctionList().remove(getIterator());
    239 }
    240 
    241 void Function::eraseFromParent() {
    242   getParent()->getFunctionList().erase(getIterator());
    243 }
    244 
    245 //===----------------------------------------------------------------------===//
    246 // Function Implementation
    247 //===----------------------------------------------------------------------===//
    248 
    249 Function::Function(FunctionType *Ty, LinkageTypes Linkage, const Twine &name,
    250                    Module *ParentModule)
    251     : GlobalObject(Ty, Value::FunctionVal,
    252                    OperandTraits<Function>::op_begin(this), 0, Linkage, name),
    253       Ty(Ty) {
    254   assert(FunctionType::isValidReturnType(getReturnType()) &&
    255          "invalid return type");
    256   setGlobalObjectSubClassData(0);
    257   SymTab = new ValueSymbolTable();
    258 
    259   // If the function has arguments, mark them as lazily built.
    260   if (Ty->getNumParams())
    261     setValueSubclassData(1);   // Set the "has lazy arguments" bit.
    262 
    263   if (ParentModule)
    264     ParentModule->getFunctionList().push_back(this);
    265 
    266   // Ensure intrinsics have the right parameter attributes.
    267   // Note, the IntID field will have been set in Value::setName if this function
    268   // name is a valid intrinsic ID.
    269   if (IntID)
    270     setAttributes(Intrinsic::getAttributes(getContext(), IntID));
    271 }
    272 
    273 Function::~Function() {
    274   dropAllReferences();    // After this it is safe to delete instructions.
    275 
    276   // Delete all of the method arguments and unlink from symbol table...
    277   ArgumentList.clear();
    278   delete SymTab;
    279 
    280   // Remove the function from the on-the-side GC table.
    281   clearGC();
    282 }
    283 
    284 void Function::BuildLazyArguments() const {
    285   // Create the arguments vector, all arguments start out unnamed.
    286   FunctionType *FT = getFunctionType();
    287   for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
    288     assert(!FT->getParamType(i)->isVoidTy() &&
    289            "Cannot have void typed arguments!");
    290     ArgumentList.push_back(new Argument(FT->getParamType(i)));
    291   }
    292 
    293   // Clear the lazy arguments bit.
    294   unsigned SDC = getSubclassDataFromValue();
    295   const_cast<Function*>(this)->setValueSubclassData(SDC &= ~(1<<0));
    296 }
    297 
    298 size_t Function::arg_size() const {
    299   return getFunctionType()->getNumParams();
    300 }
    301 bool Function::arg_empty() const {
    302   return getFunctionType()->getNumParams() == 0;
    303 }
    304 
    305 void Function::setParent(Module *parent) {
    306   Parent = parent;
    307 }
    308 
    309 // dropAllReferences() - This function causes all the subinstructions to "let
    310 // go" of all references that they are maintaining.  This allows one to
    311 // 'delete' a whole class at a time, even though there may be circular
    312 // references... first all references are dropped, and all use counts go to
    313 // zero.  Then everything is deleted for real.  Note that no operations are
    314 // valid on an object that has "dropped all references", except operator
    315 // delete.
    316 //
    317 void Function::dropAllReferences() {
    318   setIsMaterializable(false);
    319 
    320   for (iterator I = begin(), E = end(); I != E; ++I)
    321     I->dropAllReferences();
    322 
    323   // Delete all basic blocks. They are now unused, except possibly by
    324   // blockaddresses, but BasicBlock's destructor takes care of those.
    325   while (!BasicBlocks.empty())
    326     BasicBlocks.begin()->eraseFromParent();
    327 
    328   // Drop uses of any optional data (real or placeholder).
    329   if (getNumOperands()) {
    330     User::dropAllReferences();
    331     setNumHungOffUseOperands(0);
    332     setValueSubclassData(getSubclassDataFromValue() & ~0xe);
    333   }
    334 
    335   // Metadata is stored in a side-table.
    336   clearMetadata();
    337 }
    338 
    339 void Function::addAttribute(unsigned i, Attribute::AttrKind attr) {
    340   AttributeSet PAL = getAttributes();
    341   PAL = PAL.addAttribute(getContext(), i, attr);
    342   setAttributes(PAL);
    343 }
    344 
    345 void Function::addAttributes(unsigned i, AttributeSet attrs) {
    346   AttributeSet PAL = getAttributes();
    347   PAL = PAL.addAttributes(getContext(), i, attrs);
    348   setAttributes(PAL);
    349 }
    350 
    351 void Function::removeAttributes(unsigned i, AttributeSet attrs) {
    352   AttributeSet PAL = getAttributes();
    353   PAL = PAL.removeAttributes(getContext(), i, attrs);
    354   setAttributes(PAL);
    355 }
    356 
    357 void Function::addDereferenceableAttr(unsigned i, uint64_t Bytes) {
    358   AttributeSet PAL = getAttributes();
    359   PAL = PAL.addDereferenceableAttr(getContext(), i, Bytes);
    360   setAttributes(PAL);
    361 }
    362 
    363 void Function::addDereferenceableOrNullAttr(unsigned i, uint64_t Bytes) {
    364   AttributeSet PAL = getAttributes();
    365   PAL = PAL.addDereferenceableOrNullAttr(getContext(), i, Bytes);
    366   setAttributes(PAL);
    367 }
    368 
    369 // Maintain the GC name for each function in an on-the-side table. This saves
    370 // allocating an additional word in Function for programs which do not use GC
    371 // (i.e., most programs) at the cost of increased overhead for clients which do
    372 // use GC.
    373 static DenseMap<const Function*,PooledStringPtr> *GCNames;
    374 static StringPool *GCNamePool;
    375 static ManagedStatic<sys::SmartRWMutex<true> > GCLock;
    376 
    377 bool Function::hasGC() const {
    378   sys::SmartScopedReader<true> Reader(*GCLock);
    379   return GCNames && GCNames->count(this);
    380 }
    381 
    382 const char *Function::getGC() const {
    383   assert(hasGC() && "Function has no collector");
    384   sys::SmartScopedReader<true> Reader(*GCLock);
    385   return *(*GCNames)[this];
    386 }
    387 
    388 void Function::setGC(const char *Str) {
    389   sys::SmartScopedWriter<true> Writer(*GCLock);
    390   if (!GCNamePool)
    391     GCNamePool = new StringPool();
    392   if (!GCNames)
    393     GCNames = new DenseMap<const Function*,PooledStringPtr>();
    394   (*GCNames)[this] = GCNamePool->intern(Str);
    395 }
    396 
    397 void Function::clearGC() {
    398   sys::SmartScopedWriter<true> Writer(*GCLock);
    399   if (GCNames) {
    400     GCNames->erase(this);
    401     if (GCNames->empty()) {
    402       delete GCNames;
    403       GCNames = nullptr;
    404       if (GCNamePool->empty()) {
    405         delete GCNamePool;
    406         GCNamePool = nullptr;
    407       }
    408     }
    409   }
    410 }
    411 
    412 /// Copy all additional attributes (those not needed to create a Function) from
    413 /// the Function Src to this one.
    414 void Function::copyAttributesFrom(const GlobalValue *Src) {
    415   GlobalObject::copyAttributesFrom(Src);
    416   const Function *SrcF = dyn_cast<Function>(Src);
    417   if (!SrcF)
    418     return;
    419 
    420   setCallingConv(SrcF->getCallingConv());
    421   setAttributes(SrcF->getAttributes());
    422   if (SrcF->hasGC())
    423     setGC(SrcF->getGC());
    424   else
    425     clearGC();
    426   if (SrcF->hasPersonalityFn())
    427     setPersonalityFn(SrcF->getPersonalityFn());
    428   if (SrcF->hasPrefixData())
    429     setPrefixData(SrcF->getPrefixData());
    430   if (SrcF->hasPrologueData())
    431     setPrologueData(SrcF->getPrologueData());
    432 }
    433 
    434 /// \brief This does the actual lookup of an intrinsic ID which
    435 /// matches the given function name.
    436 static Intrinsic::ID lookupIntrinsicID(const ValueName *ValName) {
    437   unsigned Len = ValName->getKeyLength();
    438   const char *Name = ValName->getKeyData();
    439 
    440 #define GET_FUNCTION_RECOGNIZER
    441 #include "llvm/IR/Intrinsics.gen"
    442 #undef GET_FUNCTION_RECOGNIZER
    443 
    444   return Intrinsic::not_intrinsic;
    445 }
    446 
    447 void Function::recalculateIntrinsicID() {
    448   const ValueName *ValName = this->getValueName();
    449   if (!ValName || !isIntrinsic()) {
    450     IntID = Intrinsic::not_intrinsic;
    451     return;
    452   }
    453   IntID = lookupIntrinsicID(ValName);
    454 }
    455 
    456 /// Returns a stable mangling for the type specified for use in the name
    457 /// mangling scheme used by 'any' types in intrinsic signatures.  The mangling
    458 /// of named types is simply their name.  Manglings for unnamed types consist
    459 /// of a prefix ('p' for pointers, 'a' for arrays, 'f_' for functions)
    460 /// combined with the mangling of their component types.  A vararg function
    461 /// type will have a suffix of 'vararg'.  Since function types can contain
    462 /// other function types, we close a function type mangling with suffix 'f'
    463 /// which can't be confused with it's prefix.  This ensures we don't have
    464 /// collisions between two unrelated function types. Otherwise, you might
    465 /// parse ffXX as f(fXX) or f(fX)X.  (X is a placeholder for any other type.)
    466 /// Manglings of integers, floats, and vectors ('i', 'f', and 'v' prefix in most
    467 /// cases) fall back to the MVT codepath, where they could be mangled to
    468 /// 'x86mmx', for example; matching on derived types is not sufficient to mangle
    469 /// everything.
    470 static std::string getMangledTypeStr(Type* Ty) {
    471   std::string Result;
    472   if (PointerType* PTyp = dyn_cast<PointerType>(Ty)) {
    473     Result += "p" + llvm::utostr(PTyp->getAddressSpace()) +
    474       getMangledTypeStr(PTyp->getElementType());
    475   } else if (ArrayType* ATyp = dyn_cast<ArrayType>(Ty)) {
    476     Result += "a" + llvm::utostr(ATyp->getNumElements()) +
    477       getMangledTypeStr(ATyp->getElementType());
    478   } else if (StructType* STyp = dyn_cast<StructType>(Ty)) {
    479     assert(!STyp->isLiteral() && "TODO: implement literal types");
    480     Result += STyp->getName();
    481   } else if (FunctionType* FT = dyn_cast<FunctionType>(Ty)) {
    482     Result += "f_" + getMangledTypeStr(FT->getReturnType());
    483     for (size_t i = 0; i < FT->getNumParams(); i++)
    484       Result += getMangledTypeStr(FT->getParamType(i));
    485     if (FT->isVarArg())
    486       Result += "vararg";
    487     // Ensure nested function types are distinguishable.
    488     Result += "f";
    489   } else if (isa<VectorType>(Ty))
    490     Result += "v" + utostr(Ty->getVectorNumElements()) +
    491       getMangledTypeStr(Ty->getVectorElementType());
    492   else if (Ty)
    493     Result += EVT::getEVT(Ty).getEVTString();
    494   return Result;
    495 }
    496 
    497 std::string Intrinsic::getName(ID id, ArrayRef<Type*> Tys) {
    498   assert(id < num_intrinsics && "Invalid intrinsic ID!");
    499   static const char * const Table[] = {
    500     "not_intrinsic",
    501 #define GET_INTRINSIC_NAME_TABLE
    502 #include "llvm/IR/Intrinsics.gen"
    503 #undef GET_INTRINSIC_NAME_TABLE
    504   };
    505   if (Tys.empty())
    506     return Table[id];
    507   std::string Result(Table[id]);
    508   for (unsigned i = 0; i < Tys.size(); ++i) {
    509     Result += "." + getMangledTypeStr(Tys[i]);
    510   }
    511   return Result;
    512 }
    513 
    514 
    515 /// IIT_Info - These are enumerators that describe the entries returned by the
    516 /// getIntrinsicInfoTableEntries function.
    517 ///
    518 /// NOTE: This must be kept in synch with the copy in TblGen/IntrinsicEmitter!
    519 enum IIT_Info {
    520   // Common values should be encoded with 0-15.
    521   IIT_Done = 0,
    522   IIT_I1   = 1,
    523   IIT_I8   = 2,
    524   IIT_I16  = 3,
    525   IIT_I32  = 4,
    526   IIT_I64  = 5,
    527   IIT_F16  = 6,
    528   IIT_F32  = 7,
    529   IIT_F64  = 8,
    530   IIT_V2   = 9,
    531   IIT_V4   = 10,
    532   IIT_V8   = 11,
    533   IIT_V16  = 12,
    534   IIT_V32  = 13,
    535   IIT_PTR  = 14,
    536   IIT_ARG  = 15,
    537 
    538   // Values from 16+ are only encodable with the inefficient encoding.
    539   IIT_V64  = 16,
    540   IIT_MMX  = 17,
    541   IIT_TOKEN = 18,
    542   IIT_METADATA = 19,
    543   IIT_EMPTYSTRUCT = 20,
    544   IIT_STRUCT2 = 21,
    545   IIT_STRUCT3 = 22,
    546   IIT_STRUCT4 = 23,
    547   IIT_STRUCT5 = 24,
    548   IIT_EXTEND_ARG = 25,
    549   IIT_TRUNC_ARG = 26,
    550   IIT_ANYPTR = 27,
    551   IIT_V1   = 28,
    552   IIT_VARARG = 29,
    553   IIT_HALF_VEC_ARG = 30,
    554   IIT_SAME_VEC_WIDTH_ARG = 31,
    555   IIT_PTR_TO_ARG = 32,
    556   IIT_VEC_OF_PTRS_TO_ELT = 33,
    557   IIT_I128 = 34,
    558   IIT_V512 = 35,
    559   IIT_V1024 = 36
    560 };
    561 
    562 
    563 static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
    564                       SmallVectorImpl<Intrinsic::IITDescriptor> &OutputTable) {
    565   IIT_Info Info = IIT_Info(Infos[NextElt++]);
    566   unsigned StructElts = 2;
    567   using namespace Intrinsic;
    568 
    569   switch (Info) {
    570   case IIT_Done:
    571     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Void, 0));
    572     return;
    573   case IIT_VARARG:
    574     OutputTable.push_back(IITDescriptor::get(IITDescriptor::VarArg, 0));
    575     return;
    576   case IIT_MMX:
    577     OutputTable.push_back(IITDescriptor::get(IITDescriptor::MMX, 0));
    578     return;
    579   case IIT_TOKEN:
    580     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Token, 0));
    581     return;
    582   case IIT_METADATA:
    583     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Metadata, 0));
    584     return;
    585   case IIT_F16:
    586     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Half, 0));
    587     return;
    588   case IIT_F32:
    589     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Float, 0));
    590     return;
    591   case IIT_F64:
    592     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Double, 0));
    593     return;
    594   case IIT_I1:
    595     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 1));
    596     return;
    597   case IIT_I8:
    598     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 8));
    599     return;
    600   case IIT_I16:
    601     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer,16));
    602     return;
    603   case IIT_I32:
    604     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 32));
    605     return;
    606   case IIT_I64:
    607     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 64));
    608     return;
    609   case IIT_I128:
    610     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Integer, 128));
    611     return;
    612   case IIT_V1:
    613     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 1));
    614     DecodeIITType(NextElt, Infos, OutputTable);
    615     return;
    616   case IIT_V2:
    617     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 2));
    618     DecodeIITType(NextElt, Infos, OutputTable);
    619     return;
    620   case IIT_V4:
    621     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 4));
    622     DecodeIITType(NextElt, Infos, OutputTable);
    623     return;
    624   case IIT_V8:
    625     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 8));
    626     DecodeIITType(NextElt, Infos, OutputTable);
    627     return;
    628   case IIT_V16:
    629     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 16));
    630     DecodeIITType(NextElt, Infos, OutputTable);
    631     return;
    632   case IIT_V32:
    633     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 32));
    634     DecodeIITType(NextElt, Infos, OutputTable);
    635     return;
    636   case IIT_V64:
    637     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 64));
    638     DecodeIITType(NextElt, Infos, OutputTable);
    639     return;
    640   case IIT_V512:
    641     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 512));
    642     DecodeIITType(NextElt, Infos, OutputTable);
    643     return;
    644   case IIT_V1024:
    645     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Vector, 1024));
    646     DecodeIITType(NextElt, Infos, OutputTable);
    647     return;
    648   case IIT_PTR:
    649     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer, 0));
    650     DecodeIITType(NextElt, Infos, OutputTable);
    651     return;
    652   case IIT_ANYPTR: {  // [ANYPTR addrspace, subtype]
    653     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Pointer,
    654                                              Infos[NextElt++]));
    655     DecodeIITType(NextElt, Infos, OutputTable);
    656     return;
    657   }
    658   case IIT_ARG: {
    659     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    660     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Argument, ArgInfo));
    661     return;
    662   }
    663   case IIT_EXTEND_ARG: {
    664     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    665     OutputTable.push_back(IITDescriptor::get(IITDescriptor::ExtendArgument,
    666                                              ArgInfo));
    667     return;
    668   }
    669   case IIT_TRUNC_ARG: {
    670     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    671     OutputTable.push_back(IITDescriptor::get(IITDescriptor::TruncArgument,
    672                                              ArgInfo));
    673     return;
    674   }
    675   case IIT_HALF_VEC_ARG: {
    676     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    677     OutputTable.push_back(IITDescriptor::get(IITDescriptor::HalfVecArgument,
    678                                              ArgInfo));
    679     return;
    680   }
    681   case IIT_SAME_VEC_WIDTH_ARG: {
    682     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    683     OutputTable.push_back(IITDescriptor::get(IITDescriptor::SameVecWidthArgument,
    684                                              ArgInfo));
    685     return;
    686   }
    687   case IIT_PTR_TO_ARG: {
    688     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    689     OutputTable.push_back(IITDescriptor::get(IITDescriptor::PtrToArgument,
    690                                              ArgInfo));
    691     return;
    692   }
    693   case IIT_VEC_OF_PTRS_TO_ELT: {
    694     unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
    695     OutputTable.push_back(IITDescriptor::get(IITDescriptor::VecOfPtrsToElt,
    696                                              ArgInfo));
    697     return;
    698   }
    699   case IIT_EMPTYSTRUCT:
    700     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct, 0));
    701     return;
    702   case IIT_STRUCT5: ++StructElts; // FALL THROUGH.
    703   case IIT_STRUCT4: ++StructElts; // FALL THROUGH.
    704   case IIT_STRUCT3: ++StructElts; // FALL THROUGH.
    705   case IIT_STRUCT2: {
    706     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct,StructElts));
    707 
    708     for (unsigned i = 0; i != StructElts; ++i)
    709       DecodeIITType(NextElt, Infos, OutputTable);
    710     return;
    711   }
    712   }
    713   llvm_unreachable("unhandled");
    714 }
    715 
    716 
    717 #define GET_INTRINSIC_GENERATOR_GLOBAL
    718 #include "llvm/IR/Intrinsics.gen"
    719 #undef GET_INTRINSIC_GENERATOR_GLOBAL
    720 
    721 void Intrinsic::getIntrinsicInfoTableEntries(ID id,
    722                                              SmallVectorImpl<IITDescriptor> &T){
    723   // Check to see if the intrinsic's type was expressible by the table.
    724   unsigned TableVal = IIT_Table[id-1];
    725 
    726   // Decode the TableVal into an array of IITValues.
    727   SmallVector<unsigned char, 8> IITValues;
    728   ArrayRef<unsigned char> IITEntries;
    729   unsigned NextElt = 0;
    730   if ((TableVal >> 31) != 0) {
    731     // This is an offset into the IIT_LongEncodingTable.
    732     IITEntries = IIT_LongEncodingTable;
    733 
    734     // Strip sentinel bit.
    735     NextElt = (TableVal << 1) >> 1;
    736   } else {
    737     // Decode the TableVal into an array of IITValues.  If the entry was encoded
    738     // into a single word in the table itself, decode it now.
    739     do {
    740       IITValues.push_back(TableVal & 0xF);
    741       TableVal >>= 4;
    742     } while (TableVal);
    743 
    744     IITEntries = IITValues;
    745     NextElt = 0;
    746   }
    747 
    748   // Okay, decode the table into the output vector of IITDescriptors.
    749   DecodeIITType(NextElt, IITEntries, T);
    750   while (NextElt != IITEntries.size() && IITEntries[NextElt] != 0)
    751     DecodeIITType(NextElt, IITEntries, T);
    752 }
    753 
    754 
    755 static Type *DecodeFixedType(ArrayRef<Intrinsic::IITDescriptor> &Infos,
    756                              ArrayRef<Type*> Tys, LLVMContext &Context) {
    757   using namespace Intrinsic;
    758   IITDescriptor D = Infos.front();
    759   Infos = Infos.slice(1);
    760 
    761   switch (D.Kind) {
    762   case IITDescriptor::Void: return Type::getVoidTy(Context);
    763   case IITDescriptor::VarArg: return Type::getVoidTy(Context);
    764   case IITDescriptor::MMX: return Type::getX86_MMXTy(Context);
    765   case IITDescriptor::Token: return Type::getTokenTy(Context);
    766   case IITDescriptor::Metadata: return Type::getMetadataTy(Context);
    767   case IITDescriptor::Half: return Type::getHalfTy(Context);
    768   case IITDescriptor::Float: return Type::getFloatTy(Context);
    769   case IITDescriptor::Double: return Type::getDoubleTy(Context);
    770 
    771   case IITDescriptor::Integer:
    772     return IntegerType::get(Context, D.Integer_Width);
    773   case IITDescriptor::Vector:
    774     return VectorType::get(DecodeFixedType(Infos, Tys, Context),D.Vector_Width);
    775   case IITDescriptor::Pointer:
    776     return PointerType::get(DecodeFixedType(Infos, Tys, Context),
    777                             D.Pointer_AddressSpace);
    778   case IITDescriptor::Struct: {
    779     Type *Elts[5];
    780     assert(D.Struct_NumElements <= 5 && "Can't handle this yet");
    781     for (unsigned i = 0, e = D.Struct_NumElements; i != e; ++i)
    782       Elts[i] = DecodeFixedType(Infos, Tys, Context);
    783     return StructType::get(Context, makeArrayRef(Elts,D.Struct_NumElements));
    784   }
    785 
    786   case IITDescriptor::Argument:
    787     return Tys[D.getArgumentNumber()];
    788   case IITDescriptor::ExtendArgument: {
    789     Type *Ty = Tys[D.getArgumentNumber()];
    790     if (VectorType *VTy = dyn_cast<VectorType>(Ty))
    791       return VectorType::getExtendedElementVectorType(VTy);
    792 
    793     return IntegerType::get(Context, 2 * cast<IntegerType>(Ty)->getBitWidth());
    794   }
    795   case IITDescriptor::TruncArgument: {
    796     Type *Ty = Tys[D.getArgumentNumber()];
    797     if (VectorType *VTy = dyn_cast<VectorType>(Ty))
    798       return VectorType::getTruncatedElementVectorType(VTy);
    799 
    800     IntegerType *ITy = cast<IntegerType>(Ty);
    801     assert(ITy->getBitWidth() % 2 == 0);
    802     return IntegerType::get(Context, ITy->getBitWidth() / 2);
    803   }
    804   case IITDescriptor::HalfVecArgument:
    805     return VectorType::getHalfElementsVectorType(cast<VectorType>(
    806                                                   Tys[D.getArgumentNumber()]));
    807   case IITDescriptor::SameVecWidthArgument: {
    808     Type *EltTy = DecodeFixedType(Infos, Tys, Context);
    809     Type *Ty = Tys[D.getArgumentNumber()];
    810     if (VectorType *VTy = dyn_cast<VectorType>(Ty)) {
    811       return VectorType::get(EltTy, VTy->getNumElements());
    812     }
    813     llvm_unreachable("unhandled");
    814   }
    815   case IITDescriptor::PtrToArgument: {
    816     Type *Ty = Tys[D.getArgumentNumber()];
    817     return PointerType::getUnqual(Ty);
    818   }
    819   case IITDescriptor::VecOfPtrsToElt: {
    820     Type *Ty = Tys[D.getArgumentNumber()];
    821     VectorType *VTy = dyn_cast<VectorType>(Ty);
    822     if (!VTy)
    823       llvm_unreachable("Expected an argument of Vector Type");
    824     Type *EltTy = VTy->getVectorElementType();
    825     return VectorType::get(PointerType::getUnqual(EltTy),
    826                            VTy->getNumElements());
    827   }
    828  }
    829   llvm_unreachable("unhandled");
    830 }
    831 
    832 
    833 
    834 FunctionType *Intrinsic::getType(LLVMContext &Context,
    835                                  ID id, ArrayRef<Type*> Tys) {
    836   SmallVector<IITDescriptor, 8> Table;
    837   getIntrinsicInfoTableEntries(id, Table);
    838 
    839   ArrayRef<IITDescriptor> TableRef = Table;
    840   Type *ResultTy = DecodeFixedType(TableRef, Tys, Context);
    841 
    842   SmallVector<Type*, 8> ArgTys;
    843   while (!TableRef.empty())
    844     ArgTys.push_back(DecodeFixedType(TableRef, Tys, Context));
    845 
    846   // DecodeFixedType returns Void for IITDescriptor::Void and IITDescriptor::VarArg
    847   // If we see void type as the type of the last argument, it is vararg intrinsic
    848   if (!ArgTys.empty() && ArgTys.back()->isVoidTy()) {
    849     ArgTys.pop_back();
    850     return FunctionType::get(ResultTy, ArgTys, true);
    851   }
    852   return FunctionType::get(ResultTy, ArgTys, false);
    853 }
    854 
    855 bool Intrinsic::isOverloaded(ID id) {
    856 #define GET_INTRINSIC_OVERLOAD_TABLE
    857 #include "llvm/IR/Intrinsics.gen"
    858 #undef GET_INTRINSIC_OVERLOAD_TABLE
    859 }
    860 
    861 bool Intrinsic::isLeaf(ID id) {
    862   switch (id) {
    863   default:
    864     return true;
    865 
    866   case Intrinsic::experimental_gc_statepoint:
    867   case Intrinsic::experimental_patchpoint_void:
    868   case Intrinsic::experimental_patchpoint_i64:
    869     return false;
    870   }
    871 }
    872 
    873 /// This defines the "Intrinsic::getAttributes(ID id)" method.
    874 #define GET_INTRINSIC_ATTRIBUTES
    875 #include "llvm/IR/Intrinsics.gen"
    876 #undef GET_INTRINSIC_ATTRIBUTES
    877 
    878 Function *Intrinsic::getDeclaration(Module *M, ID id, ArrayRef<Type*> Tys) {
    879   // There can never be multiple globals with the same name of different types,
    880   // because intrinsics must be a specific type.
    881   return
    882     cast<Function>(M->getOrInsertFunction(getName(id, Tys),
    883                                           getType(M->getContext(), id, Tys)));
    884 }
    885 
    886 // This defines the "Intrinsic::getIntrinsicForGCCBuiltin()" method.
    887 #define GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
    888 #include "llvm/IR/Intrinsics.gen"
    889 #undef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
    890 
    891 // This defines the "Intrinsic::getIntrinsicForMSBuiltin()" method.
    892 #define GET_LLVM_INTRINSIC_FOR_MS_BUILTIN
    893 #include "llvm/IR/Intrinsics.gen"
    894 #undef GET_LLVM_INTRINSIC_FOR_MS_BUILTIN
    895 
    896 /// hasAddressTaken - returns true if there are any uses of this function
    897 /// other than direct calls or invokes to it.
    898 bool Function::hasAddressTaken(const User* *PutOffender) const {
    899   for (const Use &U : uses()) {
    900     const User *FU = U.getUser();
    901     if (isa<BlockAddress>(FU))
    902       continue;
    903     if (!isa<CallInst>(FU) && !isa<InvokeInst>(FU))
    904       return PutOffender ? (*PutOffender = FU, true) : true;
    905     ImmutableCallSite CS(cast<Instruction>(FU));
    906     if (!CS.isCallee(&U))
    907       return PutOffender ? (*PutOffender = FU, true) : true;
    908   }
    909   return false;
    910 }
    911 
    912 bool Function::isDefTriviallyDead() const {
    913   // Check the linkage
    914   if (!hasLinkOnceLinkage() && !hasLocalLinkage() &&
    915       !hasAvailableExternallyLinkage())
    916     return false;
    917 
    918   // Check if the function is used by anything other than a blockaddress.
    919   for (const User *U : users())
    920     if (!isa<BlockAddress>(U))
    921       return false;
    922 
    923   return true;
    924 }
    925 
    926 /// callsFunctionThatReturnsTwice - Return true if the function has a call to
    927 /// setjmp or other function that gcc recognizes as "returning twice".
    928 bool Function::callsFunctionThatReturnsTwice() const {
    929   for (const_inst_iterator
    930          I = inst_begin(this), E = inst_end(this); I != E; ++I) {
    931     ImmutableCallSite CS(&*I);
    932     if (CS && CS.hasFnAttr(Attribute::ReturnsTwice))
    933       return true;
    934   }
    935 
    936   return false;
    937 }
    938 
    939 Constant *Function::getPersonalityFn() const {
    940   assert(hasPersonalityFn() && getNumOperands());
    941   return cast<Constant>(Op<0>());
    942 }
    943 
    944 void Function::setPersonalityFn(Constant *Fn) {
    945   if (Fn)
    946     setHungoffOperand<0>(Fn);
    947   setValueSubclassDataBit(3, Fn != nullptr);
    948 }
    949 
    950 Constant *Function::getPrefixData() const {
    951   assert(hasPrefixData() && getNumOperands());
    952   return cast<Constant>(Op<1>());
    953 }
    954 
    955 void Function::setPrefixData(Constant *PrefixData) {
    956   if (PrefixData)
    957     setHungoffOperand<1>(PrefixData);
    958   setValueSubclassDataBit(1, PrefixData != nullptr);
    959 }
    960 
    961 Constant *Function::getPrologueData() const {
    962   assert(hasPrologueData() && getNumOperands());
    963   return cast<Constant>(Op<2>());
    964 }
    965 
    966 void Function::setPrologueData(Constant *PrologueData) {
    967   if (PrologueData)
    968     setHungoffOperand<2>(PrologueData);
    969   setValueSubclassDataBit(2, PrologueData != nullptr);
    970 }
    971 
    972 void Function::allocHungoffUselist() {
    973   // If we've already allocated a uselist, stop here.
    974   if (getNumOperands())
    975     return;
    976 
    977   allocHungoffUses(3, /*IsPhi=*/ false);
    978   setNumHungOffUseOperands(3);
    979 
    980   // Initialize the uselist with placeholder operands to allow traversal.
    981   auto *CPN = ConstantPointerNull::get(Type::getInt1PtrTy(getContext(), 0));
    982   Op<0>().set(CPN);
    983   Op<1>().set(CPN);
    984   Op<2>().set(CPN);
    985 }
    986 
    987 template <int Idx>
    988 void Function::setHungoffOperand(Constant *C) {
    989   assert(C && "Cannot set hungoff operand to nullptr");
    990   allocHungoffUselist();
    991   Op<Idx>().set(C);
    992 }
    993 
    994 void Function::setValueSubclassDataBit(unsigned Bit, bool On) {
    995   assert(Bit < 16 && "SubclassData contains only 16 bits");
    996   if (On)
    997     setValueSubclassData(getSubclassDataFromValue() | (1 << Bit));
    998   else
    999     setValueSubclassData(getSubclassDataFromValue() & ~(1 << Bit));
   1000 }
   1001 
   1002 void Function::setEntryCount(uint64_t Count) {
   1003   MDBuilder MDB(getContext());
   1004   setMetadata(LLVMContext::MD_prof, MDB.createFunctionEntryCount(Count));
   1005 }
   1006 
   1007 Optional<uint64_t> Function::getEntryCount() const {
   1008   MDNode *MD = getMetadata(LLVMContext::MD_prof);
   1009   if (MD && MD->getOperand(0))
   1010     if (MDString *MDS = dyn_cast<MDString>(MD->getOperand(0)))
   1011       if (MDS->getString().equals("function_entry_count")) {
   1012         ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(1));
   1013         return CI->getValue().getZExtValue();
   1014       }
   1015   return None;
   1016 }
   1017