1 //===-- llvm/Attributes.h - Container for Attributes ------------*- 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 /// \file 11 /// \brief This file contains the simple types necessary to represent the 12 /// attributes associated with functions and their calls. 13 /// 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_IR_ATTRIBUTES_H 17 #define LLVM_IR_ATTRIBUTES_H 18 19 #include "llvm/ADT/ArrayRef.h" 20 #include "llvm/ADT/FoldingSet.h" 21 #include "llvm/Support/PointerLikeTypeTraits.h" 22 #include <bitset> 23 #include <cassert> 24 #include <map> 25 #include <string> 26 27 namespace llvm { 28 29 class AttrBuilder; 30 class AttributeImpl; 31 class AttributeSetImpl; 32 class AttributeSetNode; 33 class Constant; 34 template<typename T> struct DenseMapInfo; 35 class LLVMContext; 36 class Type; 37 38 //===----------------------------------------------------------------------===// 39 /// \class 40 /// \brief Functions, function parameters, and return types can have attributes 41 /// to indicate how they should be treated by optimizations and code 42 /// generation. This class represents one of those attributes. It's light-weight 43 /// and should be passed around by-value. 44 class Attribute { 45 public: 46 /// This enumeration lists the attributes that can be associated with 47 /// parameters, function results, or the function itself. 48 /// 49 /// Note: The `uwtable' attribute is about the ABI or the user mandating an 50 /// entry in the unwind table. The `nounwind' attribute is about an exception 51 /// passing by the function. 52 /// 53 /// In a theoretical system that uses tables for profiling and SjLj for 54 /// exceptions, they would be fully independent. In a normal system that uses 55 /// tables for both, the semantics are: 56 /// 57 /// nil = Needs an entry because an exception might pass by. 58 /// nounwind = No need for an entry 59 /// uwtable = Needs an entry because the ABI says so and because 60 /// an exception might pass by. 61 /// uwtable + nounwind = Needs an entry because the ABI says so. 62 63 enum AttrKind { 64 // IR-Level Attributes 65 None, ///< No attributes have been set 66 Alignment, ///< Alignment of parameter (5 bits) 67 ///< stored as log2 of alignment with +1 bias 68 ///< 0 means unaligned (different from align(1)) 69 AlwaysInline, ///< inline=always 70 Builtin, ///< Callee is recognized as a builtin, despite 71 ///< nobuiltin attribute on its declaration. 72 ByVal, ///< Pass structure by value 73 Cold, ///< Marks function as being in a cold path. 74 InlineHint, ///< Source said inlining was desirable 75 InReg, ///< Force argument to be passed in register 76 MinSize, ///< Function must be optimized for size first 77 Naked, ///< Naked function 78 Nest, ///< Nested function static chain 79 NoAlias, ///< Considered to not alias after call 80 NoBuiltin, ///< Callee isn't recognized as a builtin 81 NoCapture, ///< Function creates no aliases of pointer 82 NoDuplicate, ///< Call cannot be duplicated 83 NoImplicitFloat, ///< Disable implicit floating point insts 84 NoInline, ///< inline=never 85 NonLazyBind, ///< Function is called early and/or 86 ///< often, so lazy binding isn't worthwhile 87 NoRedZone, ///< Disable redzone 88 NoReturn, ///< Mark the function as not returning 89 NoUnwind, ///< Function doesn't unwind stack 90 OptimizeForSize, ///< opt_size 91 ReadNone, ///< Function does not access memory 92 ReadOnly, ///< Function only reads from memory 93 Returned, ///< Return value is always equal to this argument 94 ReturnsTwice, ///< Function can return twice 95 SExt, ///< Sign extended before/after call 96 StackAlignment, ///< Alignment of stack for function (3 bits) 97 ///< stored as log2 of alignment with +1 bias 0 98 ///< means unaligned (different from 99 ///< alignstack=(1)) 100 StackProtect, ///< Stack protection. 101 StackProtectReq, ///< Stack protection required. 102 StackProtectStrong, ///< Strong Stack protection. 103 StructRet, ///< Hidden pointer to structure to return 104 SanitizeAddress, ///< AddressSanitizer is on. 105 SanitizeThread, ///< ThreadSanitizer is on. 106 SanitizeMemory, ///< MemorySanitizer is on. 107 UWTable, ///< Function must be in a unwind table 108 ZExt, ///< Zero extended before/after call 109 110 EndAttrKinds ///< Sentinal value useful for loops 111 }; 112 private: 113 AttributeImpl *pImpl; 114 Attribute(AttributeImpl *A) : pImpl(A) {} 115 public: 116 Attribute() : pImpl(0) {} 117 118 //===--------------------------------------------------------------------===// 119 // Attribute Construction 120 //===--------------------------------------------------------------------===// 121 122 /// \brief Return a uniquified Attribute object. 123 static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0); 124 static Attribute get(LLVMContext &Context, StringRef Kind, 125 StringRef Val = StringRef()); 126 127 /// \brief Return a uniquified Attribute object that has the specific 128 /// alignment set. 129 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align); 130 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align); 131 132 //===--------------------------------------------------------------------===// 133 // Attribute Accessors 134 //===--------------------------------------------------------------------===// 135 136 /// \brief Return true if the attribute is an Attribute::AttrKind type. 137 bool isEnumAttribute() const; 138 139 /// \brief Return true if the attribute is an alignment attribute. 140 bool isAlignAttribute() const; 141 142 /// \brief Return true if the attribute is a string (target-dependent) 143 /// attribute. 144 bool isStringAttribute() const; 145 146 /// \brief Return true if the attribute is present. 147 bool hasAttribute(AttrKind Val) const; 148 149 /// \brief Return true if the target-dependent attribute is present. 150 bool hasAttribute(StringRef Val) const; 151 152 /// \brief Return the attribute's kind as an enum (Attribute::AttrKind). This 153 /// requires the attribute to be an enum or alignment attribute. 154 Attribute::AttrKind getKindAsEnum() const; 155 156 /// \brief Return the attribute's value as an integer. This requires that the 157 /// attribute be an alignment attribute. 158 uint64_t getValueAsInt() const; 159 160 /// \brief Return the attribute's kind as a string. This requires the 161 /// attribute to be a string attribute. 162 StringRef getKindAsString() const; 163 164 /// \brief Return the attribute's value as a string. This requires the 165 /// attribute to be a string attribute. 166 StringRef getValueAsString() const; 167 168 /// \brief Returns the alignment field of an attribute as a byte alignment 169 /// value. 170 unsigned getAlignment() const; 171 172 /// \brief Returns the stack alignment field of an attribute as a byte 173 /// alignment value. 174 unsigned getStackAlignment() const; 175 176 /// \brief The Attribute is converted to a string of equivalent mnemonic. This 177 /// is, presumably, for writing out the mnemonics for the assembly writer. 178 std::string getAsString(bool InAttrGrp = false) const; 179 180 /// \brief Equality and non-equality operators. 181 bool operator==(Attribute A) const { return pImpl == A.pImpl; } 182 bool operator!=(Attribute A) const { return pImpl != A.pImpl; } 183 184 /// \brief Less-than operator. Useful for sorting the attributes list. 185 bool operator<(Attribute A) const; 186 187 void Profile(FoldingSetNodeID &ID) const { 188 ID.AddPointer(pImpl); 189 } 190 }; 191 192 //===----------------------------------------------------------------------===// 193 /// \class 194 /// \brief This class holds the attributes for a function, its return value, and 195 /// its parameters. You access the attributes for each of them via an index into 196 /// the AttributeSet object. The function attributes are at index 197 /// `AttributeSet::FunctionIndex', the return value is at index 198 /// `AttributeSet::ReturnIndex', and the attributes for the parameters start at 199 /// index `1'. 200 class AttributeSet { 201 public: 202 enum AttrIndex { 203 ReturnIndex = 0U, 204 FunctionIndex = ~0U 205 }; 206 private: 207 friend class AttrBuilder; 208 friend class AttributeSetImpl; 209 template <typename Ty> friend struct DenseMapInfo; 210 211 /// \brief The attributes that we are managing. This can be null to represent 212 /// the empty attributes list. 213 AttributeSetImpl *pImpl; 214 215 /// \brief The attributes for the specified index are returned. 216 AttributeSetNode *getAttributes(unsigned Index) const; 217 218 /// \brief Create an AttributeSet with the specified parameters in it. 219 static AttributeSet get(LLVMContext &C, 220 ArrayRef<std::pair<unsigned, Attribute> > Attrs); 221 static AttributeSet get(LLVMContext &C, 222 ArrayRef<std::pair<unsigned, 223 AttributeSetNode*> > Attrs); 224 225 static AttributeSet getImpl(LLVMContext &C, 226 ArrayRef<std::pair<unsigned, 227 AttributeSetNode*> > Attrs); 228 229 230 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {} 231 public: 232 AttributeSet() : pImpl(0) {} 233 234 //===--------------------------------------------------------------------===// 235 // AttributeSet Construction and Mutation 236 //===--------------------------------------------------------------------===// 237 238 /// \brief Return an AttributeSet with the specified parameters in it. 239 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs); 240 static AttributeSet get(LLVMContext &C, unsigned Index, 241 ArrayRef<Attribute::AttrKind> Kind); 242 static AttributeSet get(LLVMContext &C, unsigned Index, AttrBuilder &B); 243 244 /// \brief Add an attribute to the attribute set at the given index. Since 245 /// attribute sets are immutable, this returns a new set. 246 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 247 Attribute::AttrKind Attr) const; 248 249 /// \brief Add an attribute to the attribute set at the given index. Since 250 /// attribute sets are immutable, this returns a new set. 251 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 252 StringRef Kind) const; 253 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 254 StringRef Kind, StringRef Value) const; 255 256 /// \brief Add attributes to the attribute set at the given index. Since 257 /// attribute sets are immutable, this returns a new set. 258 AttributeSet addAttributes(LLVMContext &C, unsigned Index, 259 AttributeSet Attrs) const; 260 261 /// \brief Remove the specified attribute at the specified index from this 262 /// attribute list. Since attribute lists are immutable, this returns the new 263 /// list. 264 AttributeSet removeAttribute(LLVMContext &C, unsigned Index, 265 Attribute::AttrKind Attr) const; 266 267 /// \brief Remove the specified attributes at the specified index from this 268 /// attribute list. Since attribute lists are immutable, this returns the new 269 /// list. 270 AttributeSet removeAttributes(LLVMContext &C, unsigned Index, 271 AttributeSet Attrs) const; 272 273 //===--------------------------------------------------------------------===// 274 // AttributeSet Accessors 275 //===--------------------------------------------------------------------===// 276 277 /// \brief Retrieve the LLVM context. 278 LLVMContext &getContext() const; 279 280 /// \brief The attributes for the specified index are returned. 281 AttributeSet getParamAttributes(unsigned Index) const; 282 283 /// \brief The attributes for the ret value are returned. 284 AttributeSet getRetAttributes() const; 285 286 /// \brief The function attributes are returned. 287 AttributeSet getFnAttributes() const; 288 289 /// \brief Return true if the attribute exists at the given index. 290 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const; 291 292 /// \brief Return true if the attribute exists at the given index. 293 bool hasAttribute(unsigned Index, StringRef Kind) const; 294 295 /// \brief Return true if attribute exists at the given index. 296 bool hasAttributes(unsigned Index) const; 297 298 /// \brief Return true if the specified attribute is set for at least one 299 /// parameter or for the return value. 300 bool hasAttrSomewhere(Attribute::AttrKind Attr) const; 301 302 /// \brief Return the attribute object that exists at the given index. 303 Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const; 304 305 /// \brief Return the attribute object that exists at the given index. 306 Attribute getAttribute(unsigned Index, StringRef Kind) const; 307 308 /// \brief Return the alignment for the specified function parameter. 309 unsigned getParamAlignment(unsigned Index) const; 310 311 /// \brief Get the stack alignment. 312 unsigned getStackAlignment(unsigned Index) const; 313 314 /// \brief Return the attributes at the index as a string. 315 std::string getAsString(unsigned Index, bool InAttrGrp = false) const; 316 317 typedef ArrayRef<Attribute>::iterator iterator; 318 319 iterator begin(unsigned Slot) const; 320 iterator end(unsigned Slot) const; 321 322 /// operator==/!= - Provide equality predicates. 323 bool operator==(const AttributeSet &RHS) const { 324 return pImpl == RHS.pImpl; 325 } 326 bool operator!=(const AttributeSet &RHS) const { 327 return pImpl != RHS.pImpl; 328 } 329 330 //===--------------------------------------------------------------------===// 331 // AttributeSet Introspection 332 //===--------------------------------------------------------------------===// 333 334 // FIXME: Remove this. 335 uint64_t Raw(unsigned Index) const; 336 337 /// \brief Return a raw pointer that uniquely identifies this attribute list. 338 void *getRawPointer() const { 339 return pImpl; 340 } 341 342 /// \brief Return true if there are no attributes. 343 bool isEmpty() const { 344 return getNumSlots() == 0; 345 } 346 347 /// \brief Return the number of slots used in this attribute list. This is 348 /// the number of arguments that have an attribute set on them (including the 349 /// function itself). 350 unsigned getNumSlots() const; 351 352 /// \brief Return the index for the given slot. 353 unsigned getSlotIndex(unsigned Slot) const; 354 355 /// \brief Return the attributes at the given slot. 356 AttributeSet getSlotAttributes(unsigned Slot) const; 357 358 void dump() const; 359 }; 360 361 //===----------------------------------------------------------------------===// 362 /// \class 363 /// \brief Provide DenseMapInfo for AttributeSet. 364 template<> struct DenseMapInfo<AttributeSet> { 365 static inline AttributeSet getEmptyKey() { 366 uintptr_t Val = static_cast<uintptr_t>(-1); 367 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 368 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 369 } 370 static inline AttributeSet getTombstoneKey() { 371 uintptr_t Val = static_cast<uintptr_t>(-2); 372 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 373 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 374 } 375 static unsigned getHashValue(AttributeSet AS) { 376 return (unsigned((uintptr_t)AS.pImpl) >> 4) ^ 377 (unsigned((uintptr_t)AS.pImpl) >> 9); 378 } 379 static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; } 380 }; 381 382 //===----------------------------------------------------------------------===// 383 /// \class 384 /// \brief This class is used in conjunction with the Attribute::get method to 385 /// create an Attribute object. The object itself is uniquified. The Builder's 386 /// value, however, is not. So this can be used as a quick way to test for 387 /// equality, presence of attributes, etc. 388 class AttrBuilder { 389 std::bitset<Attribute::EndAttrKinds> Attrs; 390 std::map<std::string, std::string> TargetDepAttrs; 391 uint64_t Alignment; 392 uint64_t StackAlignment; 393 public: 394 AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0) {} 395 explicit AttrBuilder(uint64_t Val) 396 : Attrs(0), Alignment(0), StackAlignment(0) { 397 addRawValue(Val); 398 } 399 AttrBuilder(const Attribute &A) : Attrs(0), Alignment(0), StackAlignment(0) { 400 addAttribute(A); 401 } 402 AttrBuilder(AttributeSet AS, unsigned Idx); 403 AttrBuilder(const AttrBuilder &B) 404 : Attrs(B.Attrs), 405 TargetDepAttrs(B.TargetDepAttrs.begin(), B.TargetDepAttrs.end()), 406 Alignment(B.Alignment), StackAlignment(B.StackAlignment) {} 407 408 void clear(); 409 410 /// \brief Add an attribute to the builder. 411 AttrBuilder &addAttribute(Attribute::AttrKind Val); 412 413 /// \brief Add the Attribute object to the builder. 414 AttrBuilder &addAttribute(Attribute A); 415 416 /// \brief Add the target-dependent attribute to the builder. 417 AttrBuilder &addAttribute(StringRef A, StringRef V = StringRef()); 418 419 /// \brief Remove an attribute from the builder. 420 AttrBuilder &removeAttribute(Attribute::AttrKind Val); 421 422 /// \brief Remove the attributes from the builder. 423 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index); 424 425 /// \brief Remove the target-dependent attribute to the builder. 426 AttrBuilder &removeAttribute(StringRef A); 427 428 /// \brief Add the attributes from the builder. 429 AttrBuilder &merge(const AttrBuilder &B); 430 431 /// \brief Return true if the builder has the specified attribute. 432 bool contains(Attribute::AttrKind A) const { 433 assert((unsigned)A < Attribute::EndAttrKinds && "Attribute out of range!"); 434 return Attrs[A]; 435 } 436 437 /// \brief Return true if the builder has the specified target-dependent 438 /// attribute. 439 bool contains(StringRef A) const; 440 441 /// \brief Return true if the builder has IR-level attributes. 442 bool hasAttributes() const; 443 444 /// \brief Return true if the builder has any attribute that's in the 445 /// specified attribute. 446 bool hasAttributes(AttributeSet A, uint64_t Index) const; 447 448 /// \brief Return true if the builder has an alignment attribute. 449 bool hasAlignmentAttr() const; 450 451 /// \brief Retrieve the alignment attribute, if it exists. 452 uint64_t getAlignment() const { return Alignment; } 453 454 /// \brief Retrieve the stack alignment attribute, if it exists. 455 uint64_t getStackAlignment() const { return StackAlignment; } 456 457 /// \brief This turns an int alignment (which must be a power of 2) into the 458 /// form used internally in Attribute. 459 AttrBuilder &addAlignmentAttr(unsigned Align); 460 461 /// \brief This turns an int stack alignment (which must be a power of 2) into 462 /// the form used internally in Attribute. 463 AttrBuilder &addStackAlignmentAttr(unsigned Align); 464 465 /// \brief Return true if the builder contains no target-independent 466 /// attributes. 467 bool empty() const { return Attrs.none(); } 468 469 // Iterators for target-dependent attributes. 470 typedef std::pair<std::string, std::string> td_type; 471 typedef std::map<std::string, std::string>::iterator td_iterator; 472 typedef std::map<std::string, std::string>::const_iterator td_const_iterator; 473 474 td_iterator td_begin() { return TargetDepAttrs.begin(); } 475 td_iterator td_end() { return TargetDepAttrs.end(); } 476 477 td_const_iterator td_begin() const { return TargetDepAttrs.begin(); } 478 td_const_iterator td_end() const { return TargetDepAttrs.end(); } 479 480 bool td_empty() const { return TargetDepAttrs.empty(); } 481 482 bool operator==(const AttrBuilder &B); 483 bool operator!=(const AttrBuilder &B) { 484 return !(*this == B); 485 } 486 487 // FIXME: Remove this in 4.0. 488 489 /// \brief Add the raw value to the internal representation. 490 AttrBuilder &addRawValue(uint64_t Val); 491 }; 492 493 namespace AttributeFuncs { 494 495 /// \brief Which attributes cannot be applied to a type. 496 AttributeSet typeIncompatible(Type *Ty, uint64_t Index); 497 498 } // end AttributeFuncs namespace 499 500 } // end llvm namespace 501 502 #endif 503
