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/CallSite.h"
  20 #include "llvm/Support/LeakDetector.h"
  21 #include "llvm/Support/ManagedStatic.h"
  22 #include "llvm/Support/StringPool.h"
  23 #include "llvm/Support/RWMutex.h"
  24 #include "llvm/Support/Threading.h"
  25 #include "SymbolTableListTraitsImpl.h"
  26 #include "llvm/ADT/DenseMap.h"
  27 #include "llvm/ADT/StringExtras.h"
  28 using namespace llvm;
  29
  30
  31 // Explicit instantiations of SymbolTableListTraits since some of the methods
  32 // are not in the public header file...
  33 template class llvm::SymbolTableListTraits<Argument, Function>;
  34 template class llvm::SymbolTableListTraits<BasicBlock, Function>;
  35
  36 //===----------------------------------------------------------------------===//
  37 // Argument Implementation
  38 //===----------------------------------------------------------------------===//
  39
  40 Argument::Argument(const Type *Ty, const Twine &Name, Function *Par)
  41   : Value(Ty, Value::ArgumentVal) {
  42   Parent = 0;
  43
  44   // Make sure that we get added to a function
  45   LeakDetector::addGarbageObject(this);
  46
  47   if (Par)
  48     Par->getArgumentList().push_back(this);
  49   setName(Name);
  50 }
  51
  52 void Argument::setParent(Function *parent) {
  53   if (getParent())
  54     LeakDetector::addGarbageObject(this);
  55   Parent = parent;
  56   if (getParent())
  57     LeakDetector::removeGarbageObject(this);
  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 /// hasByValAttr - Return true if this argument has the byval attribute on it
  75 /// in its containing function.
  76 bool Argument::hasByValAttr() const {
  77   if (!getType()->isPointerTy()) return false;
  78   return getParent()->paramHasAttr(getArgNo()+1, Attribute::ByVal);
  79 }
  80
  81 /// hasNestAttr - Return true if this argument has the nest attribute on
  82 /// it in its containing function.
  83 bool Argument::hasNestAttr() const {
  84   if (!getType()->isPointerTy()) return false;
  85   return getParent()->paramHasAttr(getArgNo()+1, Attribute::Nest);
  86 }
  87
  88 /// hasNoAliasAttr - Return true if this argument has the noalias attribute on
  89 /// it in its containing function.
  90 bool Argument::hasNoAliasAttr() const {
  91   if (!getType()->isPointerTy()) return false;
  92   return getParent()->paramHasAttr(getArgNo()+1, Attribute::NoAlias);
  93 }
  94
  95 /// hasNoCaptureAttr - Return true if this argument has the nocapture attribute
  96 /// on it in its containing function.
  97 bool Argument::hasNoCaptureAttr() const {
  98   if (!getType()->isPointerTy()) return false;
  99   return getParent()->paramHasAttr(getArgNo()+1, Attribute::NoCapture);
 100 }
 101
 102 /// hasSRetAttr - Return true if this argument has the sret attribute on
 103 /// it in its containing function.
 104 bool Argument::hasStructRetAttr() const {
 105   if (!getType()->isPointerTy()) return false;
 106   if (this != getParent()->arg_begin())
 107     return false; // StructRet param must be first param
 108   return getParent()->paramHasAttr(1, Attribute::StructRet);
 109 }
 110
 111 /// addAttr - Add a Attribute to an argument
 112 void Argument::addAttr(Attributes attr) {
 113   getParent()->addAttribute(getArgNo() + 1, attr);
 114 }
 115
 116 /// removeAttr - Remove a Attribute from an argument
 117 void Argument::removeAttr(Attributes attr) {
 118   getParent()->removeAttribute(getArgNo() + 1, attr);
 119 }
 120
 121
 122 //===----------------------------------------------------------------------===//
 123 // Helper Methods in Function
 124 //===----------------------------------------------------------------------===//
 125
 126 LLVMContext &Function::getContext() const {
 127   return getType()->getContext();
 128 }
 129
 130 const FunctionType *Function::getFunctionType() const {
 131   return cast<FunctionType>(getType()->getElementType());
 132 }
 133
 134 bool Function::isVarArg() const {
 135   return getFunctionType()->isVarArg();
 136 }
 137
 138 const Type *Function::getReturnType() const {
 139   return getFunctionType()->getReturnType();
 140 }
 141
 142 void Function::removeFromParent() {
 143   getParent()->getFunctionList().remove(this);
 144 }
 145
 146 void Function::eraseFromParent() {
 147   getParent()->getFunctionList().erase(this);
 148 }
 149
 150 //===----------------------------------------------------------------------===//
 151 // Function Implementation
 152 //===----------------------------------------------------------------------===//
 153
 154 Function::Function(const FunctionType *Ty, LinkageTypes Linkage,
 155                    const Twine &name, Module *ParentModule)
 156   : GlobalValue(PointerType::getUnqual(Ty),
 157                 Value::FunctionVal, 0, 0, Linkage, name) {
 158   assert(FunctionType::isValidReturnType(getReturnType()) &&
 159          !getReturnType()->isOpaqueTy() && "invalid return type");
 160   SymTab = new ValueSymbolTable();
 161
 162   // If the function has arguments, mark them as lazily built.
 163   if (Ty->getNumParams())
 164     setValueSubclassData(1);   // Set the "has lazy arguments" bit.
 165
 166   // Make sure that we get added to a function
 167   LeakDetector::addGarbageObject(this);
 168
 169   if (ParentModule)
 170     ParentModule->getFunctionList().push_back(this);
 171
 172   // Ensure intrinsics have the right parameter attributes.
 173   if (unsigned IID = getIntrinsicID())
 174     setAttributes(Intrinsic::getAttributes(Intrinsic::ID(IID)));
 175
 176 }
 177
 178 Function::~Function() {
 179   dropAllReferences();    // After this it is safe to delete instructions.
 180
 181   // Delete all of the method arguments and unlink from symbol table...
 182   ArgumentList.clear();
 183   delete SymTab;
 184
 185   // Remove the function from the on-the-side GC table.
 186   clearGC();
 187 }
 188
 189 void Function::BuildLazyArguments() const {
 190   // Create the arguments vector, all arguments start out unnamed.
 191   const FunctionType *FT = getFunctionType();
 192   for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i) {
 193     assert(!FT->getParamType(i)->isVoidTy() &&
 194            "Cannot have void typed arguments!");
 195     ArgumentList.push_back(new Argument(FT->getParamType(i)));
 196   }
 197
 198   // Clear the lazy arguments bit.
 199   unsigned SDC = getSubclassDataFromValue();
 200   const_cast<Function*>(this)->setValueSubclassData(SDC &= ~1);
 201 }
 202
 203 size_t Function::arg_size() const {
 204   return getFunctionType()->getNumParams();
 205 }
 206 bool Function::arg_empty() const {
 207   return getFunctionType()->getNumParams() == 0;
 208 }
 209
 210 void Function::setParent(Module *parent) {
 211   if (getParent())
 212     LeakDetector::addGarbageObject(this);
 213   Parent = parent;
 214   if (getParent())
 215     LeakDetector::removeGarbageObject(this);
 216 }
 217
 218 // dropAllReferences() - This function causes all the subinstructions to "let
 219 // go" of all references that they are maintaining.  This allows one to
 220 // 'delete' a whole class at a time, even though there may be circular
 221 // references... first all references are dropped, and all use counts go to
 222 // zero.  Then everything is deleted for real.  Note that no operations are
 223 // valid on an object that has "dropped all references", except operator
 224 // delete.
 225 //
 226 void Function::dropAllReferences() {
 227   for (iterator I = begin(), E = end(); I != E; ++I)
 228     I->dropAllReferences();
 229
 230   // Delete all basic blocks. They are now unused, except possibly by
 231   // blockaddresses, but BasicBlock's destructor takes care of those.
 232   while (!BasicBlocks.empty())
 233     BasicBlocks.begin()->eraseFromParent();
 234 }
 235
 236 void Function::addAttribute(unsigned i, Attributes attr) {
 237   AttrListPtr PAL = getAttributes();
 238   PAL = PAL.addAttr(i, attr);
 239   setAttributes(PAL);
 240 }
 241
 242 void Function::removeAttribute(unsigned i, Attributes attr) {
 243   AttrListPtr PAL = getAttributes();
 244   PAL = PAL.removeAttr(i, attr);
 245   setAttributes(PAL);
 246 }
 247
 248 // Maintain the GC name for each function in an on-the-side table. This saves
 249 // allocating an additional word in Function for programs which do not use GC
 250 // (i.e., most programs) at the cost of increased overhead for clients which do
 251 // use GC.
 252 static DenseMap<const Function*,PooledStringPtr> *GCNames;
 253 static StringPool *GCNamePool;
 254 static ManagedStatic<sys::SmartRWMutex<true> > GCLock;
 255
 256 bool Function::hasGC() const {
 257   sys::SmartScopedReader<true> Reader(*GCLock);
 258   return GCNames && GCNames->count(this);
 259 }
 260
 261 const char *Function::getGC() const {
 262   assert(hasGC() && "Function has no collector");
 263   sys::SmartScopedReader<true> Reader(*GCLock);
 264   return *(*GCNames)[this];
 265 }
 266
 267 void Function::setGC(const char *Str) {
 268   sys::SmartScopedWriter<true> Writer(*GCLock);
 269   if (!GCNamePool)
 270     GCNamePool = new StringPool();
 271   if (!GCNames)
 272     GCNames = new DenseMap<const Function*,PooledStringPtr>();
 273   (*GCNames)[this] = GCNamePool->intern(Str);
 274 }
 275
 276 void Function::clearGC() {
 277   sys::SmartScopedWriter<true> Writer(*GCLock);
 278   if (GCNames) {
 279     GCNames->erase(this);
 280     if (GCNames->empty()) {
 281       delete GCNames;
 282       GCNames = 0;
 283       if (GCNamePool->empty()) {
 284         delete GCNamePool;
 285         GCNamePool = 0;
 286       }
 287     }
 288   }
 289 }
 290
 291 /// copyAttributesFrom - copy all additional attributes (those not needed to
 292 /// create a Function) from the Function Src to this one.
 293 void Function::copyAttributesFrom(const GlobalValue *Src) {
 294   assert(isa<Function>(Src) && "Expected a Function!");
 295   GlobalValue::copyAttributesFrom(Src);
 296   const Function *SrcF = cast<Function>(Src);
 297   setCallingConv(SrcF->getCallingConv());
 298   setAttributes(SrcF->getAttributes());
 299   if (SrcF->hasGC())
 300     setGC(SrcF->getGC());
 301   else
 302     clearGC();
 303 }
 304
 305 /// getIntrinsicID - This method returns the ID number of the specified
 306 /// function, or Intrinsic::not_intrinsic if the function is not an
 307 /// intrinsic, or if the pointer is null.  This value is always defined to be
 308 /// zero to allow easy checking for whether a function is intrinsic or not.  The
 309 /// particular intrinsic functions which correspond to this value are defined in
 310 /// llvm/Intrinsics.h.
 311 ///
 312 unsigned Function::getIntrinsicID() const {
 313   const ValueName *ValName = this->getValueName();
 314   if (!ValName)
 315     return 0;
 316   unsigned Len = ValName->getKeyLength();
 317   const char *Name = ValName->getKeyData();
 318
 319   if (Len < 5 || Name[4] != '.' || Name[0] != 'l' || Name[1] != 'l'
 320       || Name[2] != 'v' || Name[3] != 'm')
 321     return 0;  // All intrinsics start with 'llvm.'
 322
 323 #define GET_FUNCTION_RECOGNIZER
 324 #include "llvm/Intrinsics.gen"
 325 #undef GET_FUNCTION_RECOGNIZER
 326   return 0;
 327 }
 328
 329 std::string Intrinsic::getName(ID id, const Type **Tys, unsigned numTys) {
 330   assert(id < num_intrinsics && "Invalid intrinsic ID!");
 331   const char * const Table[] = {
 332     "not_intrinsic",
 333 #define GET_INTRINSIC_NAME_TABLE
 334 #include "llvm/Intrinsics.gen"
 335 #undef GET_INTRINSIC_NAME_TABLE
 336   };
 337   if (numTys == 0)
 338     return Table[id];
 339   std::string Result(Table[id]);
 340   for (unsigned i = 0; i < numTys; ++i) {
 341     if (const PointerType* PTyp = dyn_cast<PointerType>(Tys[i])) {
 342       Result += ".p" + llvm::utostr(PTyp->getAddressSpace()) +
 343                 EVT::getEVT(PTyp->getElementType()).getEVTString();
 344     }
 345     else if (Tys[i])
 346       Result += "." + EVT::getEVT(Tys[i]).getEVTString();
 347   }
 348   return Result;
 349 }
 350
 351 const FunctionType *Intrinsic::getType(LLVMContext &Context,
 352                                        ID id, const Type **Tys,
 353                                        unsigned numTys) {
 354   const Type *ResultTy = NULL;
 355   std::vector<const Type*> ArgTys;
 356   bool IsVarArg = false;
 357
 358 #define GET_INTRINSIC_GENERATOR
 359 #include "llvm/Intrinsics.gen"
 360 #undef GET_INTRINSIC_GENERATOR
 361
 362   return FunctionType::get(ResultTy, ArgTys, IsVarArg);
 363 }
 364
 365 bool Intrinsic::isOverloaded(ID id) {
 366   const bool OTable[] = {
 367     false,
 368 #define GET_INTRINSIC_OVERLOAD_TABLE
 369 #include "llvm/Intrinsics.gen"
 370 #undef GET_INTRINSIC_OVERLOAD_TABLE
 371   };
 372   return OTable[id];
 373 }
 374
 375 /// This defines the "Intrinsic::getAttributes(ID id)" method.
 376 #define GET_INTRINSIC_ATTRIBUTES
 377 #include "llvm/Intrinsics.gen"
 378 #undef GET_INTRINSIC_ATTRIBUTES
 379
 380 Function *Intrinsic::getDeclaration(Module *M, ID id, const Type **Tys,
 381                                     unsigned numTys) {
 382   // There can never be multiple globals with the same name of different types,
 383   // because intrinsics must be a specific type.
 384   return
 385     cast<Function>(M->getOrInsertFunction(getName(id, Tys, numTys),
 386                                           getType(M->getContext(),
 387                                                   id, Tys, numTys)));
 388 }
 389
 390 // This defines the "Intrinsic::getIntrinsicForGCCBuiltin()" method.
 391 #define GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
 392 #include "llvm/Intrinsics.gen"
 393 #undef GET_LLVM_INTRINSIC_FOR_GCC_BUILTIN
 394
 395 /// hasAddressTaken - returns true if there are any uses of this function
 396 /// other than direct calls or invokes to it.
 397 bool Function::hasAddressTaken(const User* *PutOffender) const {
 398   for (Value::const_use_iterator I = use_begin(), E = use_end(); I != E; ++I) {
 399     const User *U = *I;
 400     if (!isa<CallInst>(U) && !isa<InvokeInst>(U))
 401       return PutOffender ? (*PutOffender = U, true) : true;
 402     ImmutableCallSite CS(cast<Instruction>(U));
 403     if (!CS.isCallee(I))
 404       return PutOffender ? (*PutOffender = U, true) : true;
 405   }
 406   return false;
 407 }
 408
 409 // vim: sw=2 ai