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_FUNCTION_H 19 #define LLVM_FUNCTION_H 20 21 #include "llvm/GlobalValue.h" 22 #include "llvm/CallingConv.h" 23 #include "llvm/BasicBlock.h" 24 #include "llvm/Argument.h" 25 #include "llvm/Attributes.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 AttrListPtr AttributeList; ///< 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 unsigned intrinsicID; ///< ID of intrinsic, 0 otherwise 97 98 friend class SymbolTableListTraits<Function, Module>; 99 100 void setParent(Module *parent); 101 102 /// hasLazyArguments/CheckLazyArguments - The argument list of a function is 103 /// built on demand, so that the list isn't allocated until the first client 104 /// needs it. The hasLazyArguments predicate returns true if the arg list 105 /// hasn't been set up yet. 106 bool hasLazyArguments() const { 107 return getSubclassDataFromValue() & 1; 108 } 109 void CheckLazyArguments() const { 110 if (hasLazyArguments()) 111 BuildLazyArguments(); 112 } 113 void BuildLazyArguments() const; 114 115 unsigned initIntrinsicID() const; 116 117 Function(const Function&); // DO NOT IMPLEMENT 118 void operator=(const Function&); // DO NOT IMPLEMENT 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 /// instrinsic, 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. 152 /// 153 unsigned getIntrinsicID() const { return intrinsicID; } 154 bool isIntrinsic() const { return intrinsicID != 0; } 155 156 /// getCallingConv()/setCallingConv(CC) - These method get and set the 157 /// calling convention of this function. The enum values for the known 158 /// calling conventions are defined in CallingConv.h. 159 CallingConv::ID getCallingConv() const { 160 return static_cast<CallingConv::ID>(getSubclassDataFromValue() >> 1); 161 } 162 void setCallingConv(CallingConv::ID CC) { 163 setValueSubclassData((getSubclassDataFromValue() & 1) | 164 (static_cast<unsigned>(CC) << 1)); 165 } 166 167 /// getAttributes - Return the attribute list for this Function. 168 /// 169 const AttrListPtr &getAttributes() const { return AttributeList; } 170 171 /// setAttributes - Set the attribute list for this Function. 172 /// 173 void setAttributes(const AttrListPtr &attrs) { AttributeList = attrs; } 174 175 /// hasFnAttr - Return true if this function has the given attribute. 176 bool hasFnAttr(Attributes N) const { 177 // Function Attributes are stored at ~0 index 178 return AttributeList.paramHasAttr(~0U, N); 179 } 180 181 /// addFnAttr - Add function attributes to this function. 182 /// 183 void addFnAttr(Attributes N) { 184 // Function Attributes are stored at ~0 index 185 addAttribute(~0U, N); 186 } 187 188 /// removeFnAttr - Remove function attributes from this function. 189 /// 190 void removeFnAttr(Attributes N) { 191 // Function Attributes are stored at ~0 index 192 removeAttribute(~0U, N); 193 } 194 195 /// hasGC/getGC/setGC/clearGC - The name of the garbage collection algorithm 196 /// to use during code generation. 197 bool hasGC() const; 198 const char *getGC() const; 199 void setGC(const char *Str); 200 void clearGC(); 201 202 /// @brief Determine whether the function has the given attribute. 203 bool paramHasAttr(unsigned i, Attributes attr) const { 204 return AttributeList.paramHasAttr(i, attr); 205 } 206 207 /// addAttribute - adds the attribute to the list of attributes. 208 void addAttribute(unsigned i, Attributes attr); 209 210 /// removeAttribute - removes the attribute from the list of attributes. 211 void removeAttribute(unsigned i, Attributes attr); 212 213 /// @brief Extract the alignment for a call or parameter (0=unknown). 214 unsigned getParamAlignment(unsigned i) const { 215 return AttributeList.getParamAlignment(i); 216 } 217 218 /// @brief Determine if the function does not access memory. 219 bool doesNotAccessMemory() const { 220 return hasFnAttr(Attribute::ReadNone); 221 } 222 void setDoesNotAccessMemory(bool DoesNotAccessMemory = true) { 223 if (DoesNotAccessMemory) addFnAttr(Attribute::ReadNone); 224 else removeFnAttr(Attribute::ReadNone); 225 } 226 227 /// @brief Determine if the function does not access or only reads memory. 228 bool onlyReadsMemory() const { 229 return doesNotAccessMemory() || hasFnAttr(Attribute::ReadOnly); 230 } 231 void setOnlyReadsMemory(bool OnlyReadsMemory = true) { 232 if (OnlyReadsMemory) addFnAttr(Attribute::ReadOnly); 233 else removeFnAttr(Attribute::ReadOnly | Attribute::ReadNone); 234 } 235 236 /// @brief Determine if the function cannot return. 237 bool doesNotReturn() const { 238 return hasFnAttr(Attribute::NoReturn); 239 } 240 void setDoesNotReturn(bool DoesNotReturn = true) { 241 if (DoesNotReturn) addFnAttr(Attribute::NoReturn); 242 else removeFnAttr(Attribute::NoReturn); 243 } 244 245 /// @brief Determine if the function cannot unwind. 246 bool doesNotThrow() const { 247 return hasFnAttr(Attribute::NoUnwind); 248 } 249 void setDoesNotThrow(bool DoesNotThrow = true) { 250 if (DoesNotThrow) addFnAttr(Attribute::NoUnwind); 251 else removeFnAttr(Attribute::NoUnwind); 252 } 253 254 /// @brief True if the ABI mandates (or the user requested) that this 255 /// function be in a unwind table. 256 bool hasUWTable() const { 257 return hasFnAttr(Attribute::UWTable); 258 } 259 void setHasUWTable(bool HasUWTable = true) { 260 if (HasUWTable) 261 addFnAttr(Attribute::UWTable); 262 else 263 removeFnAttr(Attribute::UWTable); 264 } 265 266 /// @brief True if this function needs an unwind table. 267 bool needsUnwindTableEntry() const { 268 return hasUWTable() || !doesNotThrow(); 269 } 270 271 /// @brief Determine if the function returns a structure through first 272 /// pointer argument. 273 bool hasStructRetAttr() const { 274 return paramHasAttr(1, Attribute::StructRet); 275 } 276 277 /// @brief Determine if the parameter does not alias other parameters. 278 /// @param n The parameter to check. 1 is the first parameter, 0 is the return 279 bool doesNotAlias(unsigned n) const { 280 return paramHasAttr(n, Attribute::NoAlias); 281 } 282 void setDoesNotAlias(unsigned n, bool DoesNotAlias = true) { 283 if (DoesNotAlias) addAttribute(n, Attribute::NoAlias); 284 else removeAttribute(n, Attribute::NoAlias); 285 } 286 287 /// @brief Determine if the parameter can be captured. 288 /// @param n The parameter to check. 1 is the first parameter, 0 is the return 289 bool doesNotCapture(unsigned n) const { 290 return paramHasAttr(n, Attribute::NoCapture); 291 } 292 void setDoesNotCapture(unsigned n, bool DoesNotCapture = true) { 293 if (DoesNotCapture) addAttribute(n, Attribute::NoCapture); 294 else removeAttribute(n, Attribute::NoCapture); 295 } 296 297 /// copyAttributesFrom - copy all additional attributes (those not needed to 298 /// create a Function) from the Function Src to this one. 299 void copyAttributesFrom(const GlobalValue *Src); 300 301 /// deleteBody - This method deletes the body of the function, and converts 302 /// the linkage to external. 303 /// 304 void deleteBody() { 305 dropAllReferences(); 306 setLinkage(ExternalLinkage); 307 } 308 309 /// removeFromParent - This method unlinks 'this' from the containing module, 310 /// but does not delete it. 311 /// 312 virtual void removeFromParent(); 313 314 /// eraseFromParent - This method unlinks 'this' from the containing module 315 /// and deletes it. 316 /// 317 virtual void eraseFromParent(); 318 319 320 /// Get the underlying elements of the Function... the basic block list is 321 /// empty for external functions. 322 /// 323 const ArgumentListType &getArgumentList() const { 324 CheckLazyArguments(); 325 return ArgumentList; 326 } 327 ArgumentListType &getArgumentList() { 328 CheckLazyArguments(); 329 return ArgumentList; 330 } 331 static iplist<Argument> Function::*getSublistAccess(Argument*) { 332 return &Function::ArgumentList; 333 } 334 335 const BasicBlockListType &getBasicBlockList() const { return BasicBlocks; } 336 BasicBlockListType &getBasicBlockList() { return BasicBlocks; } 337 static iplist<BasicBlock> Function::*getSublistAccess(BasicBlock*) { 338 return &Function::BasicBlocks; 339 } 340 341 const BasicBlock &getEntryBlock() const { return front(); } 342 BasicBlock &getEntryBlock() { return front(); } 343 344 //===--------------------------------------------------------------------===// 345 // Symbol Table Accessing functions... 346 347 /// getSymbolTable() - Return the symbol table... 348 /// 349 inline ValueSymbolTable &getValueSymbolTable() { return *SymTab; } 350 inline const ValueSymbolTable &getValueSymbolTable() const { return *SymTab; } 351 352 353 //===--------------------------------------------------------------------===// 354 // BasicBlock iterator forwarding functions 355 // 356 iterator begin() { return BasicBlocks.begin(); } 357 const_iterator begin() const { return BasicBlocks.begin(); } 358 iterator end () { return BasicBlocks.end(); } 359 const_iterator end () const { return BasicBlocks.end(); } 360 361 size_t size() const { return BasicBlocks.size(); } 362 bool empty() const { return BasicBlocks.empty(); } 363 const BasicBlock &front() const { return BasicBlocks.front(); } 364 BasicBlock &front() { return BasicBlocks.front(); } 365 const BasicBlock &back() const { return BasicBlocks.back(); } 366 BasicBlock &back() { return BasicBlocks.back(); } 367 368 //===--------------------------------------------------------------------===// 369 // Argument iterator forwarding functions 370 // 371 arg_iterator arg_begin() { 372 CheckLazyArguments(); 373 return ArgumentList.begin(); 374 } 375 const_arg_iterator arg_begin() const { 376 CheckLazyArguments(); 377 return ArgumentList.begin(); 378 } 379 arg_iterator arg_end() { 380 CheckLazyArguments(); 381 return ArgumentList.end(); 382 } 383 const_arg_iterator arg_end() const { 384 CheckLazyArguments(); 385 return ArgumentList.end(); 386 } 387 388 size_t arg_size() const; 389 bool arg_empty() const; 390 391 /// viewCFG - This function is meant for use from the debugger. You can just 392 /// say 'call F->viewCFG()' and a ghostview window should pop up from the 393 /// program, displaying the CFG of the current function with the code for each 394 /// basic block inside. This depends on there being a 'dot' and 'gv' program 395 /// in your path. 396 /// 397 void viewCFG() const; 398 399 /// viewCFGOnly - This function is meant for use from the debugger. It works 400 /// just like viewCFG, but it does not include the contents of basic blocks 401 /// into the nodes, just the label. If you are only interested in the CFG 402 /// this can make the graph smaller. 403 /// 404 void viewCFGOnly() const; 405 406 /// Methods for support type inquiry through isa, cast, and dyn_cast: 407 static inline bool classof(const Function *) { return true; } 408 static inline bool classof(const Value *V) { 409 return V->getValueID() == Value::FunctionVal; 410 } 411 412 /// dropAllReferences() - This method causes all the subinstructions to "let 413 /// go" of all references that they are maintaining. This allows one to 414 /// 'delete' a whole module at a time, even though there may be circular 415 /// references... first all references are dropped, and all use counts go to 416 /// zero. Then everything is deleted for real. Note that no operations are 417 /// valid on an object that has "dropped all references", except operator 418 /// delete. 419 /// 420 /// Since no other object in the module can have references into the body of a 421 /// function, dropping all references deletes the entire body of the function, 422 /// including any contained basic blocks. 423 /// 424 void dropAllReferences(); 425 426 /// hasAddressTaken - returns true if there are any uses of this function 427 /// other than direct calls or invokes to it. Optionally passes back the 428 /// offending user for diagnostic purposes. 429 /// 430 bool hasAddressTaken(const User** = 0) const; 431 432 /// callsFunctionThatReturnsTwice - Return true if the function has a call to 433 /// setjmp or other function that gcc recognizes as "returning twice". 434 bool callsFunctionThatReturnsTwice() const; 435 436 private: 437 // Shadow Value::setValueSubclassData with a private forwarding method so that 438 // subclasses cannot accidentally use it. 439 void setValueSubclassData(unsigned short D) { 440 Value::setValueSubclassData(D); 441 } 442 }; 443 444 inline ValueSymbolTable * 445 ilist_traits<BasicBlock>::getSymTab(Function *F) { 446 return F ? &F->getValueSymbolTable() : 0; 447 } 448 449 inline ValueSymbolTable * 450 ilist_traits<Argument>::getSymTab(Function *F) { 451 return F ? &F->getValueSymbolTable() : 0; 452 } 453 454 } // End llvm namespace 455 456 #endif 457