lib/VMCore/Function.cpp

   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/LeakDetector.h"
  20 #include "llvm/Support/ManagedStatic.h"
  21 #include "llvm/Support/StringPool.h"
  22 #include "llvm/System/RWMutex.h"
  23 #include "llvm/System/Threading.h"
  24 #include "SymbolTableListTraitsImpl.h"
  25 #include "llvm/ADT/DenseMap.h"
  26 #include "llvm/ADT/StringExtras.h"
  27 using namespace llvm;
  28
  29
  30 // Explicit instantiations of SymbolTableListTraits since some of the methods
  31 // are not in the public header file...
  32 template class SymbolTableListTraits<Argument, Function>;
  33 template class SymbolTableListTraits<BasicBlock, Function>;
  34
  35 //===----------------------------------------------------------------------===//
  36 // Argument Implementation
  37 //===----------------------------------------------------------------------===//
  38
  39 Argument::Argument(const Type *Ty, const Twine &Name, Function *Par)
  40   : Value(Ty, Value::ArgumentVal) {
  41   Parent = 0;
  42
  43   // Make sure that we get added to a function
  44   LeakDetector::addGarbageObject(this);
  45
  46   if (Par)
  47     Par->getArgumentList().push_back(this);
  48   setName(Name);
  49 }
  50
  51 void Argument::setParent(Function *parent) {
  52   if (getParent())
  53     LeakDetector::addGarbageObject(this);
  54   Parent = parent;
  55   if (getParent())
  56     LeakDetector::removeGarbageObject(this);
  57 }
  58
  59 /// getArgNo - Return the index of this formal argument in its containing
  60 /// function.  For example in "void foo(int a, float b)" a is 0 and b is 1.
  61 unsigned Argument::getArgNo() const {
  62   const Function *F = getParent();
  63   assert(F && "Argument is not in a function");
  64
  65   Function::const_arg_iterator AI = F->arg_begin();
  66   unsigned ArgIdx = 0;
  67   for (; &*AI != this; ++AI)
  68     ++ArgIdx;
  69
  70   return ArgIdx;
  71 }
  72
  73 /// hasByValAttr - Return true if this argument has the byval attribute on it
  74 /// in its containing function.
  75 bool Argument::hasByValAttr() const {
  76   if (!isa<PointerType>(getType())) return false;
  77   return getParent()->paramHasAttr(getArgNo()+1, Attribute::ByVal);
  78 }
  79
  80 /// hasNoAliasAttr - Return true if this argument has the noalias attribute on
  81 /// it in its containing function.
  82 bool Argument::hasNoAliasAttr() const {
  83   if (!isa<PointerType>(getType())) return false;
  84   return getParent()->paramHasAttr(getArgNo()+1, Attribute::NoAlias);
  85 }
  86
  87 /// hasNoCaptureAttr - Return true if this argument has the nocapture attribute
  88 /// on it in its containing function.
  89 bool Argument::hasNoCaptureAttr() const {
  90   if (!isa<PointerType>(getType())) return false;
  91   return getParent()->paramHasAttr(getArgNo()+1, Attribute::NoCapture);
  92 }
  93
  94 /// hasSRetAttr - Return true if this argument has the sret attribute on
  95 /// it in its containing function.
  96 bool Argument::hasStructRetAttr() const {
  97   if (!isa<PointerType>(getType())) return false;
  98   if (this != getParent()->arg_begin())
  99     return false; // StructRet param must be first param
 100   return getParent()->paramHasAttr(1, Attribute::StructRet);
 101 }
 102
 103 /// addAttr - Add a Attribute to an argument
 104 void Argument::addAttr(Attributes attr) {
 105   getParent()->addAttribute(getArgNo() + 1, attr);
 106 }
 107
 108 /// removeAttr - Remove a Attribute from an argument
 109 void Argument::removeAttr(Attributes attr) {
 110   getParent()->removeAttribute(getArgNo() + 1, attr);
 111 }
 112
 113
 114 //===----------------------------------------------------------------------===//
 115 // Helper Methods in Function
 116 //===----------------------------------------------------------------------===//
 117
 118 LLVMContext &Function::getContext() const {
 119   return getType()->getContext();
 120 }
 121
 122 const FunctionType *Function::getFunctionType() const {
 123   return cast<FunctionType>(getType()->getElementType());
 124 }
 125
 126 bool Function::isVarArg() const {
 127   return getFunctionType()->isVarArg();
 128 }
 129
 130 const Type *Function::getReturnType() const {
 131   return getFunctionType()->getReturnType();
 132 }
 133
 134 void Function::removeFromParent() {
 135   getParent()->getFunctionList().remove(this);
 136 }
 137
 138 void Function::eraseFromParent() {
 139   getParent()->getFunctionList().erase(this);
 140 }
 141
 142 //===----------------------------------------------------------------------===//
 143 // Function Implementation
 144 //===----------------------------------------------------------------------===//
 145
 146 Function::Function(const FunctionType *Ty, LinkageTypes Linkage,
 147                    const Twine &name, Module *ParentModule)
 148   : GlobalValue(PointerType::getUnqual(Ty),
 149                 Value::FunctionVal, 0, 0, Linkage, name) {
 150   assert(FunctionType::isValidReturnType(getReturnType()) &&
 151          !isa<OpaqueType>(getReturnType()) && "invalid return type");
 152   SymTab = new ValueSymbolTable();
 153
 154   // If the function has arguments, mark them as lazily built.
 155   if (Ty->getNumParams())
 156     SubclassData = 1;   // Set the "has lazy arguments" bit.
 157
 158   // Make sure that we get added to a function
 159   LeakDetector::addGarbageObject(this);
 160
 161   if (ParentModule)
 162     ParentModule->getFunctionList().push_back(this);
 163
 164   // Ensure intrinsics have the right parameter attributes.
 165   if (unsigned IID = getIntrinsicID())
 166     setAttributes(Intrinsic::getAttributes(Intrinsic::ID(IID)));
 167
 168 }
 169
 170 Function::~Function() {
 171   dropAllReferences();    // After this it is safe to delete instructions.
 172
 173   // Delete all of the method arguments and unlink from symbol table...
 174   ArgumentList.clear();
 175   delete SymTab;
 176
 177   // Remove the function from the on-the-side GC table.
 178   clearGC();
 179 }
 180
 181 void Function::BuildLazyArguments() const {
 182   // Create the arguments vector, all arguments start out unnamed.
 183   const FunctionType *FT = getFunctionType();
 184   for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
 185     assert(FT->getParamType(i) != Type::getVoidTy(FT->getContext()) &&
 186            "Cannot have void typed arguments!");
 187     ArgumentList.push_back(new Argument(FT->getParamType(i)));
 188   }
 189
 190   // Clear the lazy arguments bit.
 191   const_cast<Function*>(this)->SubclassData &= ~1;
 192 }
 193
 194 size_t Function::arg_size() const {
 195   return getFunctionType()->getNumParams();
 196 }
 197 bool Function::arg_empty() const {
 198   return getFunctionType()->getNumParams() == 0;
 199 }
 200
 201 void Function::setParent(Module *parent) {
 202   if (getParent())
 203     LeakDetector::addGarbageObject(this);
 204   Parent = parent;
 205   if (getParent())
 206     LeakDetector::removeGarbageObject(this);
 207 }
 208
 209 // dropAllReferences() - This function causes all the subinstructions to "let
 210 // go" of all references that they are maintaining.  This allows one to
 211 // 'delete' a whole class at a time, even though there may be circular
 212 // references... first all references are dropped, and all use counts go to
 213 // zero.  Then everything is deleted for real.  Note that no operations are
 214 // valid on an object that has "dropped all references", except operator
 215 // delete.
 216 //
 217 void Function::dropAllReferences() {
 218   for (iterator I = begin(), E = end(); I != E; ++I)
 219     I->dropAllReferences();
 220   BasicBlocks.clear();    // Delete all basic blocks...
 221 }
 222
 223 void Function::addAttribute(unsigned i, Attributes attr) {
 224   AttrListPtr PAL = getAttributes();
 225   PAL = PAL.addAttr(i, attr);
 226   setAttributes(PAL);
 227 }
 228
 229 void Function::removeAttribute(unsigned i, Attributes attr) {
 230   AttrListPtr PAL = getAttributes();
 231   PAL = PAL.removeAttr(i, attr);
 232   setAttributes(PAL);
 233 }
 234
 235 // Maintain the GC name for each function in an on-the-side table. This saves
 236 // allocating an additional word in Function for programs which do not use GC
 237 // (i.e., most programs) at the cost of increased overhead for clients which do
 238 // use GC.
 239 static DenseMap<const Function*,PooledStringPtr> *GCNames;
 240 static StringPool *GCNamePool;
 241 static ManagedStatic<sys::SmartRWMutex<true> > GCLock;
 242
 243 bool Function::hasGC() const {
 244   sys::SmartScopedReader<true> Reader(*GCLock);
 245   return GCNames && GCNames->count(this);
 246 }
 247
 248 const char *Function::getGC() const {
 249   assert(hasGC() && "Function has no collector");
 250   sys::SmartScopedReader<true> Reader(*GCLock);
 251   return *(*GCNames)[this];
 252 }
 253
 254 void Function::setGC(const char *Str) {
 255   sys::SmartScopedWriter<true> Writer(*GCLock);
 256   if (!GCNamePool)
 257     GCNamePool = new StringPool();
 258   if (!GCNames)
 259     GCNames = new DenseMap<const Function*,PooledStringPtr>();
 260   (*GCNames)[this] = GCNamePool->intern(Str);
 261 }
 262
 263 void Function::clearGC() {
 264   sys::SmartScopedWriter<true> Writer(*GCLock);
 265   if (GCNames) {
 266     GCNames->erase(this);
 267     if (GCNames->empty()) {
 268       delete GCNames;
 269       GCNames = 0;
 270       if (GCNamePool->empty()) {
 271         delete GCNamePool;
 272         GCNamePool = 0;
 273       }
 274     }
 275   }
 276 }
 277
 278 /// copyAttributesFrom - copy all additional attributes (those not needed to
 279 /// create a Function) from the Function Src to this one.
 280 void Function::copyAttributesFrom(const GlobalValue *Src) {
 281   assert(isa<Function>(Src) && "Expected a Function!");
 282   GlobalValue::copyAttributesFrom(Src);
 283   const Function *SrcF = cast<Function>(Src);
 284   setCallingConv(SrcF->getCallingConv());
 285   setAttributes(SrcF->getAttributes());
 286   if (SrcF->hasGC())
 287     setGC(SrcF->getGC());
 288   else
 289     clearGC();
 290 }
 291
 292 /// getIntrinsicID - This method returns the ID number of the specified
 293 /// function, or Intrinsic::not_intrinsic if the function is not an
 294 /// intrinsic, or if the pointer is null.  This value is always defined to be
 295 /// zero to allow easy checking for whether a function is intrinsic or not.  The
 296 /// particular intrinsic functions which correspond to this value are defined in
 297 /// llvm/Intrinsics.h.
 298 ///
 299 unsigned Function::getIntrinsicID() const {
 300   const ValueName *ValName = this->getValueName();
 301   if (!ValName)
 302     return 0;
 303   unsigned Len = ValName->getKeyLength();
 304   const char *Name = ValName->getKeyData();
 305
 306   if (Len < 5 || Name[4] != '.' || Name[0] != 'l' || Name[1] != 'l'
 307       || Name[2] != 'v' || Name[3] != 'm')
 308     return 0;  // All intrinsics start with 'llvm.'
 309
 310 #define GET_FUNCTION_RECOGNIZER
 311 #include "llvm/Intrinsics.gen"
 312 #undef GET_FUNCTION_RECOGNIZER
 313   return 0;
 314 }
 315
 316 std::string Intrinsic::getName(ID id, const Type **Tys, unsigned numTys) {
 317   assert(id < num_intrinsics && "Invalid intrinsic ID!");
 318   const char * const Table[] = {
 319     "not_intrinsic",
 320 #define GET_INTRINSIC_NAME_TABLE
 321 #include "llvm/Intrinsics.gen"
 322 #undef GET_INTRINSIC_NAME_TABLE
 323   };
 324   if (numTys == 0)
 325     return Table[id];
 326   std::string Result(Table[id]);
 327   for (unsigned i = 0; i < numTys; ++i) {
 328     if (const PointerType* PTyp = dyn_cast<PointerType>(Tys[i])) {
 329       Result += ".p" + llvm::utostr(PTyp->getAddressSpace()) +
 330                 EVT::getEVT(PTyp->getElementType()).getEVTString();
 331     }
 332     else if (Tys[i])
 333       Result += "." + EVT::getEVT(Tys[i]).getEVTString();
 334   }
 335   return Result;
 336 }
 337
 338 const FunctionType *Intrinsic::getType(LLVMContext &Context,
 339                                        ID id, const Type **Tys,
 340                                        unsigned numTys) {
 341   const Type *ResultTy = NULL;
 342   std::vector<const Type*> ArgTys;
 343   bool IsVarArg = false;
 344
 345 #define GET_INTRINSIC_GENERATOR
 346 #include "llvm/Intrinsics.gen"
 347 #undef GET_INTRINSIC_GENERATOR
 348
 349   return FunctionType::get(ResultTy, ArgTys, IsVarArg);
 350 }
 351
 352 bool Intrinsic::isOverloaded(ID id) {
 353   const bool OTable[] = {
 354     false,
 355 #define GET_INTRINSIC_OVERLOAD_TABLE
 356 #include "llvm/Intrinsics.gen"
 357 #undef GET_INTRINSIC_OVERLOAD_TABLE
 358   };
 359   return OTable[id];
 360 }
 361
 362 /// This defines the "Intrinsic::getAttributes(ID id)" method.
 363 #define GET_INTRINSIC_ATTRIBUTES
 364 #include "llvm/Intrinsics.gen"
 365 #undef GET_INTRINSIC_ATTRIBUTES
 366
 367 Function *Intrinsic::getDeclaration(Module *M, ID id, const Type **Tys,
 368                                     unsigned numTys) {
 369   // There can never be multiple globals with the same name of different types,
 370   // because intrinsics must be a specific type.
 371   return
 372     cast<Function>(M->getOrInsertFunction(getName(id, Tys, numTys),
 373                                           getType(M->getContext(),
 374                                                   id, Tys, numTys)));
 375 }
 376
 377 // This defines the "Intrinsic::getIntrinsicForGCCBuiltin()" method.
 378 #define GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
 379 #include "llvm/Intrinsics.gen"
 380 #undef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
 381
 382   /// hasAddressTaken - returns true if there are any uses of this function
 383   /// other than direct calls or invokes to it.
 384 bool Function::hasAddressTaken() const {
 385   for (Value::use_const_iterator I = use_begin(), E = use_end(); I != E; ++I) {
 386     if (I.getOperandNo() != 0 ||
 387         (!isa<CallInst>(*I) && !isa<InvokeInst>(*I)))
 388       return true;
 389   }
 390   return false;
 391 }
 392
 393 // vim: sw=2 ai