1 //===-- llvm/Function.h - Class to represent a single function --*- C++ -*-===// 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 contains the declaration of the Function class, which represents a 11 // single function/procedure in LLVM. 12 // 13 // A function basically consists of a list of basic blocks, a list of arguments, 14 // and a symbol table. 15 // 16 //===----------------------------------------------------------------------===// 17 18 #ifndef LLVM_IR_FUNCTION_H 19 #define LLVM_IR_FUNCTION_H 20 21 #include "llvm/IR/Argument.h" 22 #include "llvm/IR/Attributes.h" 23 #include "llvm/IR/BasicBlock.h" 24 #include "llvm/IR/CallingConv.h" 25 #include "llvm/IR/GlobalValue.h" 26 #include "llvm/Support/Compiler.h" 27 28 namespace llvm { 29 30 class FunctionType; 31 class LLVMContext; 32 33 // Traits for intrusive list of basic blocks... 34 template<> struct ilist_traits<BasicBlock> 35 : public SymbolTableListTraits<BasicBlock, Function> { 36 37 // createSentinel is used to get hold of the node that marks the end of the 38 // list... (same trick used here as in ilist_traits<Instruction>) 39 BasicBlock *createSentinel() const { 40 return static_cast<BasicBlock*>(&Sentinel); 41 } 42 static void destroySentinel(BasicBlock*) {} 43 44 BasicBlock *provideInitialHead() const { return createSentinel(); } 45 BasicBlock *ensureHead(BasicBlock*) const { return createSentinel(); } 46 static void noteHead(BasicBlock*, BasicBlock*) {} 47 48 static ValueSymbolTable *getSymTab(Function *ItemParent); 49 private: 50 mutable ilist_half_node<BasicBlock> Sentinel; 51 }; 52 53 template<> struct ilist_traits<Argument> 54 : public SymbolTableListTraits<Argument, Function> { 55 56 Argument *createSentinel() const { 57 return static_cast<Argument*>(&Sentinel); 58 } 59 static void destroySentinel(Argument*) {} 60 61 Argument *provideInitialHead() const { return createSentinel(); } 62 Argument *ensureHead(Argument*) const { return createSentinel(); } 63 static void noteHead(Argument*, Argument*) {} 64 65 static ValueSymbolTable *getSymTab(Function *ItemParent); 66 private: 67 mutable ilist_half_node<Argument> Sentinel; 68 }; 69 70 class Function : public GlobalValue, 71 public ilist_node<Function> { 72 public: 73 typedef iplist<Argument> ArgumentListType; 74 typedef iplist<BasicBlock> BasicBlockListType; 75 76 // BasicBlock iterators... 77 typedef BasicBlockListType::iterator iterator; 78 typedef BasicBlockListType::const_iterator const_iterator; 79 80 typedef ArgumentListType::iterator arg_iterator; 81 typedef ArgumentListType::const_iterator const_arg_iterator; 82 83 private: 84 // Important things that make up a function! 85 BasicBlockListType BasicBlocks; ///< The basic blocks 86 mutable ArgumentListType ArgumentList; ///< The formal arguments 87 ValueSymbolTable *SymTab; ///< Symbol table of args/instructions 88 AttributeSet AttributeSets; ///< Parameter attributes 89 90 // HasLazyArguments is stored in Value::SubclassData. 91 /*bool HasLazyArguments;*/ 92 93 // The Calling Convention is stored in Value::SubclassData. 94 /*CallingConv::ID CallingConvention;*/ 95 96 friend class SymbolTableListTraits<Function, Module>; 97 98 void setParent(Module *parent); 99 100 /// hasLazyArguments/CheckLazyArguments - The argument list of a function is 101 /// built on demand, so that the list isn't allocated until the first client 102 /// needs it. The hasLazyArguments predicate returns true if the arg list 103 /// hasn't been set up yet. 104 bool hasLazyArguments() const { 105 return getSubclassDataFromValue() & 1; 106 } 107 void CheckLazyArguments() const { 108 if (hasLazyArguments()) 109 BuildLazyArguments(); 110 } 111 void BuildLazyArguments() const; 112 113 Function(const Function&) LLVM_DELETED_FUNCTION; 114 void operator=(const Function&) LLVM_DELETED_FUNCTION; 115 116 /// Do the actual lookup of an intrinsic ID when the query could not be 117 /// answered from the cache. 118 unsigned lookupIntrinsicID() const LLVM_READONLY; 119 120 /// Function ctor - If the (optional) Module argument is specified, the 121 /// function is automatically inserted into the end of the function list for 122 /// the module. 123 /// 124 Function(FunctionType *Ty, LinkageTypes Linkage, 125 const Twine &N = "", Module *M = 0); 126 127 public: 128 static Function *Create(FunctionType *Ty, LinkageTypes Linkage, 129 const Twine &N = "", Module *M = 0) { 130 return new(0) Function(Ty, Linkage, N, M); 131 } 132 133 ~Function(); 134 135 Type *getReturnType() const; // Return the type of the ret val 136 FunctionType *getFunctionType() const; // Return the FunctionType for me 137 138 /// getContext - Return a pointer to the LLVMContext associated with this 139 /// function, or NULL if this function is not bound to a context yet. 140 LLVMContext &getContext() const; 141 142 /// isVarArg - Return true if this function takes a variable number of 143 /// arguments. 144 bool isVarArg() const; 145 146 /// getIntrinsicID - This method returns the ID number of the specified 147 /// function, or Intrinsic::not_intrinsic if the function is not an 148 /// intrinsic, or if the pointer is null. This value is always defined to be 149 /// zero to allow easy checking for whether a function is intrinsic or not. 150 /// The particular intrinsic functions which correspond to this value are 151 /// defined in llvm/Intrinsics.h. Results are cached in the LLVM context, 152 /// subsequent requests for the same ID return results much faster from the 153 /// cache. 154 /// 155 unsigned getIntrinsicID() const LLVM_READONLY; 156 bool isIntrinsic() const { return getName().startswith("llvm."); } 157 158 /// getCallingConv()/setCallingConv(CC) - These method get and set the 159 /// calling convention of this function. The enum values for the known 160 /// calling conventions are defined in CallingConv.h. 161 CallingConv::ID getCallingConv() const { 162 return static_cast<CallingConv::ID>(getSubclassDataFromValue() >> 1); 163 } 164 void setCallingConv(CallingConv::ID CC) { 165 setValueSubclassData((getSubclassDataFromValue() & 1) | 166 (static_cast<unsigned>(CC) << 1)); 167 } 168 169 /// getAttributes - Return the attribute list for this Function. 170 /// 171 AttributeSet getAttributes() const { return AttributeSets; } 172 173 /// setAttributes - Set the attribute list for this Function. 174 /// 175 void setAttributes(AttributeSet attrs) { AttributeSets = attrs; } 176 177 /// addFnAttr - Add function attributes to this function. 178 /// 179 void addFnAttr(Attribute::AttrKind N) { 180 setAttributes(AttributeSets.addAttribute(getContext(), 181 AttributeSet::FunctionIndex, N)); 182 } 183 184 /// addFnAttr - Add function attributes to this function. 185 /// 186 void addFnAttr(StringRef Kind) { 187 setAttributes( 188 AttributeSets.addAttribute(getContext(), 189 AttributeSet::FunctionIndex, Kind)); 190 } 191 192 /// \brief Return true if the function has the attribute. 193 bool hasFnAttribute(Attribute::AttrKind Kind) const { 194 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex, Kind); 195 } 196 bool hasFnAttribute(StringRef Kind) const { 197 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex, Kind); 198 } 199 200 /// hasGC/getGC/setGC/clearGC - The name of the garbage collection algorithm 201 /// to use during code generation. 202 bool hasGC() const; 203 const char *getGC() const; 204 void setGC(const char *Str); 205 void clearGC(); 206 207 /// @brief adds the attribute to the list of attributes. 208 void addAttribute(unsigned i, Attribute::AttrKind attr); 209 210 /// @brief adds the attributes to the list of attributes. 211 void addAttributes(unsigned i, AttributeSet attrs); 212 213 /// @brief removes the attributes from the list of attributes. 214 void removeAttributes(unsigned i, AttributeSet attr); 215 216 /// @brief Extract the alignment for a call or parameter (0=unknown). 217 unsigned getParamAlignment(unsigned i) const { 218 return AttributeSets.getParamAlignment(i); 219 } 220 221 /// @brief Determine if the function does not access memory. 222 bool doesNotAccessMemory() const { 223 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex, 224 Attribute::ReadNone); 225 } 226 void setDoesNotAccessMemory() { 227 addFnAttr(Attribute::ReadNone); 228 } 229 230 /// @brief Determine if the function does not access or only reads memory. 231 bool onlyReadsMemory() const { 232 return doesNotAccessMemory() || 233 AttributeSets.hasAttribute(AttributeSet::FunctionIndex, 234 Attribute::ReadOnly); 235 } 236 void setOnlyReadsMemory() { 237 addFnAttr(Attribute::ReadOnly); 238 } 239 240 /// @brief Determine if the function cannot return. 241 bool doesNotReturn() const { 242 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex, 243 Attribute::NoReturn); 244 } 245 void setDoesNotReturn() { 246 addFnAttr(Attribute::NoReturn); 247 } 248 249 /// @brief Determine if the function cannot unwind. 250 bool doesNotThrow() const { 251 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex, 252 Attribute::NoUnwind); 253 } 254 void setDoesNotThrow() { 255 addFnAttr(Attribute::NoUnwind); 256 } 257 258 /// @brief Determine if the call cannot be duplicated. 259 bool cannotDuplicate() const { 260 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex, 261 Attribute::NoDuplicate); 262 } 263 void setCannotDuplicate() { 264 addFnAttr(Attribute::NoDuplicate); 265 } 266 267 /// @brief True if the ABI mandates (or the user requested) that this 268 /// function be in a unwind table. 269 bool hasUWTable() const { 270 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex, 271 Attribute::UWTable); 272 } 273 void setHasUWTable() { 274 addFnAttr(Attribute::UWTable); 275 } 276 277 /// @brief True if this function needs an unwind table. 278 bool needsUnwindTableEntry() const { 279 return hasUWTable() || !doesNotThrow(); 280 } 281 282 /// @brief Determine if the function returns a structure through first 283 /// pointer argument. 284 bool hasStructRetAttr() const { 285 return AttributeSets.hasAttribute(1, Attribute::StructRet); 286 } 287 288 /// @brief Determine if the parameter does not alias other parameters. 289 /// @param n The parameter to check. 1 is the first parameter, 0 is the return 290 bool doesNotAlias(unsigned n) const { 291 return AttributeSets.hasAttribute(n, Attribute::NoAlias); 292 } 293 void setDoesNotAlias(unsigned n) { 294 addAttribute(n, Attribute::NoAlias); 295 } 296 297 /// @brief Determine if the parameter can be captured. 298 /// @param n The parameter to check. 1 is the first parameter, 0 is the return 299 bool doesNotCapture(unsigned n) const { 300 return AttributeSets.hasAttribute(n, Attribute::NoCapture); 301 } 302 void setDoesNotCapture(unsigned n) { 303 addAttribute(n, Attribute::NoCapture); 304 } 305 306 /// copyAttributesFrom - copy all additional attributes (those not needed to 307 /// create a Function) from the Function Src to this one. 308 void copyAttributesFrom(const GlobalValue *Src); 309 310 /// deleteBody - This method deletes the body of the function, and converts 311 /// the linkage to external. 312 /// 313 void deleteBody() { 314 dropAllReferences(); 315 setLinkage(ExternalLinkage); 316 } 317 318 /// removeFromParent - This method unlinks 'this' from the containing module, 319 /// but does not delete it. 320 /// 321 virtual void removeFromParent(); 322 323 /// eraseFromParent - This method unlinks 'this' from the containing module 324 /// and deletes it. 325 /// 326 virtual void eraseFromParent(); 327 328 329 /// Get the underlying elements of the Function... the basic block list is 330 /// empty for external functions. 331 /// 332 const ArgumentListType &getArgumentList() const { 333 CheckLazyArguments(); 334 return ArgumentList; 335 } 336 ArgumentListType &getArgumentList() { 337 CheckLazyArguments(); 338 return ArgumentList; 339 } 340 static iplist<Argument> Function::*getSublistAccess(Argument*) { 341 return &Function::ArgumentList; 342 } 343 344 const BasicBlockListType &getBasicBlockList() const { return BasicBlocks; } 345 BasicBlockListType &getBasicBlockList() { return BasicBlocks; } 346 static iplist<BasicBlock> Function::*getSublistAccess(BasicBlock*) { 347 return &Function::BasicBlocks; 348 } 349 350 const BasicBlock &getEntryBlock() const { return front(); } 351 BasicBlock &getEntryBlock() { return front(); } 352 353 //===--------------------------------------------------------------------===// 354 // Symbol Table Accessing functions... 355 356 /// getSymbolTable() - Return the symbol table... 357 /// 358 inline ValueSymbolTable &getValueSymbolTable() { return *SymTab; } 359 inline const ValueSymbolTable &getValueSymbolTable() const { return *SymTab; } 360 361 362 //===--------------------------------------------------------------------===// 363 // BasicBlock iterator forwarding functions 364 // 365 iterator begin() { return BasicBlocks.begin(); } 366 const_iterator begin() const { return BasicBlocks.begin(); } 367 iterator end () { return BasicBlocks.end(); } 368 const_iterator end () const { return BasicBlocks.end(); } 369 370 size_t size() const { return BasicBlocks.size(); } 371 bool empty() const { return BasicBlocks.empty(); } 372 const BasicBlock &front() const { return BasicBlocks.front(); } 373 BasicBlock &front() { return BasicBlocks.front(); } 374 const BasicBlock &back() const { return BasicBlocks.back(); } 375 BasicBlock &back() { return BasicBlocks.back(); } 376 377 //===--------------------------------------------------------------------===// 378 // Argument iterator forwarding functions 379 // 380 arg_iterator arg_begin() { 381 CheckLazyArguments(); 382 return ArgumentList.begin(); 383 } 384 const_arg_iterator arg_begin() const { 385 CheckLazyArguments(); 386 return ArgumentList.begin(); 387 } 388 arg_iterator arg_end() { 389 CheckLazyArguments(); 390 return ArgumentList.end(); 391 } 392 const_arg_iterator arg_end() const { 393 CheckLazyArguments(); 394 return ArgumentList.end(); 395 } 396 397 size_t arg_size() const; 398 bool arg_empty() const; 399 400 /// viewCFG - This function is meant for use from the debugger. You can just 401 /// say 'call F->viewCFG()' and a ghostview window should pop up from the 402 /// program, displaying the CFG of the current function with the code for each 403 /// basic block inside. This depends on there being a 'dot' and 'gv' program 404 /// in your path. 405 /// 406 void viewCFG() const; 407 408 /// viewCFGOnly - This function is meant for use from the debugger. It works 409 /// just like viewCFG, but it does not include the contents of basic blocks 410 /// into the nodes, just the label. If you are only interested in the CFG 411 /// this can make the graph smaller. 412 /// 413 void viewCFGOnly() const; 414 415 /// Methods for support type inquiry through isa, cast, and dyn_cast: 416 static inline bool classof(const Value *V) { 417 return V->getValueID() == Value::FunctionVal; 418 } 419 420 /// dropAllReferences() - This method causes all the subinstructions to "let 421 /// go" of all references that they are maintaining. This allows one to 422 /// 'delete' a whole module at a time, even though there may be circular 423 /// references... first all references are dropped, and all use counts go to 424 /// zero. Then everything is deleted for real. Note that no operations are 425 /// valid on an object that has "dropped all references", except operator 426 /// delete. 427 /// 428 /// Since no other object in the module can have references into the body of a 429 /// function, dropping all references deletes the entire body of the function, 430 /// including any contained basic blocks. 431 /// 432 void dropAllReferences(); 433 434 /// hasAddressTaken - returns true if there are any uses of this function 435 /// other than direct calls or invokes to it, or blockaddress expressions. 436 /// Optionally passes back an offending user for diagnostic purposes. 437 /// 438 bool hasAddressTaken(const User** = 0) const; 439 440 /// isDefTriviallyDead - Return true if it is trivially safe to remove 441 /// this function definition from the module (because it isn't externally 442 /// visible, does not have its address taken, and has no callers). To make 443 /// this more accurate, call removeDeadConstantUsers first. 444 bool isDefTriviallyDead() const; 445 446 /// callsFunctionThatReturnsTwice - Return true if the function has a call to 447 /// setjmp or other function that gcc recognizes as "returning twice". 448 bool callsFunctionThatReturnsTwice() const; 449 450 private: 451 // Shadow Value::setValueSubclassData with a private forwarding method so that 452 // subclasses cannot accidentally use it. 453 void setValueSubclassData(unsigned short D) { 454 Value::setValueSubclassData(D); 455 } 456 }; 457 458 inline ValueSymbolTable * 459 ilist_traits<BasicBlock>::getSymTab(Function *F) { 460 return F ? &F->getValueSymbolTable() : 0; 461 } 462 463 inline ValueSymbolTable * 464 ilist_traits<Argument>::getSymTab(Function *F) { 465 return F ? &F->getValueSymbolTable() : 0; 466 } 467 468 } // End llvm namespace 469 470 #endif 471