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/Compiler.h" 22 #include "llvm/Support/PointerLikeTypeTraits.h" 23 #include <bitset> 24 #include <cassert> 25 #include <map> 26 #include <string> 27 28 namespace llvm { 29 30 class AttrBuilder; 31 class AttributeImpl; 32 class AttributeSetImpl; 33 class AttributeSetNode; 34 class Constant; 35 template<typename T> struct DenseMapInfo; 36 class LLVMContext; 37 class Type; 38 39 //===----------------------------------------------------------------------===// 40 /// \class 41 /// \brief Functions, function parameters, and return types can have attributes 42 /// to indicate how they should be treated by optimizations and code 43 /// generation. This class represents one of those attributes. It's light-weight 44 /// and should be passed around by-value. 45 class Attribute { 46 public: 47 /// This enumeration lists the attributes that can be associated with 48 /// parameters, function results, or the function itself. 49 /// 50 /// Note: The `uwtable' attribute is about the ABI or the user mandating an 51 /// entry in the unwind table. The `nounwind' attribute is about an exception 52 /// passing by the function. 53 /// 54 /// In a theoretical system that uses tables for profiling and SjLj for 55 /// exceptions, they would be fully independent. In a normal system that uses 56 /// tables for both, the semantics are: 57 /// 58 /// nil = Needs an entry because an exception might pass by. 59 /// nounwind = No need for an entry 60 /// uwtable = Needs an entry because the ABI says so and because 61 /// an exception might pass by. 62 /// uwtable + nounwind = Needs an entry because the ABI says so. 63 64 enum AttrKind { 65 // IR-Level Attributes 66 None, ///< No attributes have been set 67 Alignment, ///< Alignment of parameter (5 bits) 68 ///< stored as log2 of alignment with +1 bias 69 ///< 0 means unaligned (different from align(1)) 70 AlwaysInline, ///< inline=always 71 Builtin, ///< Callee is recognized as a builtin, despite 72 ///< nobuiltin attribute on its declaration. 73 ByVal, ///< Pass structure by value 74 InAlloca, ///< Pass structure in an alloca 75 Cold, ///< Marks function as being in a cold path. 76 InlineHint, ///< Source said inlining was desirable 77 InReg, ///< Force argument to be passed in register 78 JumpTable, ///< Build jump-instruction tables and replace refs. 79 MinSize, ///< Function must be optimized for size first 80 Naked, ///< Naked function 81 Nest, ///< Nested function static chain 82 NoAlias, ///< Considered to not alias after call 83 NoBuiltin, ///< Callee isn't recognized as a builtin 84 NoCapture, ///< Function creates no aliases of pointer 85 NoDuplicate, ///< Call cannot be duplicated 86 NoImplicitFloat, ///< Disable implicit floating point insts 87 NoInline, ///< inline=never 88 NonLazyBind, ///< Function is called early and/or 89 ///< often, so lazy binding isn't worthwhile 90 NonNull, ///< Pointer is known to be not null 91 Dereferenceable, ///< Pointer is known to be dereferenceable 92 NoRedZone, ///< Disable redzone 93 NoReturn, ///< Mark the function as not returning 94 NoUnwind, ///< Function doesn't unwind stack 95 OptimizeForSize, ///< opt_size 96 OptimizeNone, ///< Function must not be optimized. 97 ReadNone, ///< Function does not access memory 98 ReadOnly, ///< Function only reads from memory 99 Returned, ///< Return value is always equal to this argument 100 ReturnsTwice, ///< Function can return twice 101 SExt, ///< Sign extended before/after call 102 StackAlignment, ///< Alignment of stack for function (3 bits) 103 ///< stored as log2 of alignment with +1 bias 0 104 ///< means unaligned (different from 105 ///< alignstack=(1)) 106 StackProtect, ///< Stack protection. 107 StackProtectReq, ///< Stack protection required. 108 StackProtectStrong, ///< Strong Stack protection. 109 StructRet, ///< Hidden pointer to structure to return 110 SanitizeAddress, ///< AddressSanitizer is on. 111 SanitizeThread, ///< ThreadSanitizer is on. 112 SanitizeMemory, ///< MemorySanitizer is on. 113 UWTable, ///< Function must be in a unwind table 114 ZExt, ///< Zero extended before/after call 115 116 EndAttrKinds ///< Sentinal value useful for loops 117 }; 118 private: 119 AttributeImpl *pImpl; Attribute(AttributeImpl * A)120 Attribute(AttributeImpl *A) : pImpl(A) {} 121 public: Attribute()122 Attribute() : pImpl(nullptr) {} 123 124 //===--------------------------------------------------------------------===// 125 // Attribute Construction 126 //===--------------------------------------------------------------------===// 127 128 /// \brief Return a uniquified Attribute object. 129 static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0); 130 static Attribute get(LLVMContext &Context, StringRef Kind, 131 StringRef Val = StringRef()); 132 133 /// \brief Return a uniquified Attribute object that has the specific 134 /// alignment set. 135 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align); 136 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align); 137 static Attribute getWithDereferenceableBytes(LLVMContext &Context, 138 uint64_t Bytes); 139 140 //===--------------------------------------------------------------------===// 141 // Attribute Accessors 142 //===--------------------------------------------------------------------===// 143 144 /// \brief Return true if the attribute is an Attribute::AttrKind type. 145 bool isEnumAttribute() const; 146 147 /// \brief Return true if the attribute is an integer attribute. 148 bool isIntAttribute() const; 149 150 /// \brief Return true if the attribute is a string (target-dependent) 151 /// attribute. 152 bool isStringAttribute() const; 153 154 /// \brief Return true if the attribute is present. 155 bool hasAttribute(AttrKind Val) const; 156 157 /// \brief Return true if the target-dependent attribute is present. 158 bool hasAttribute(StringRef Val) const; 159 160 /// \brief Return the attribute's kind as an enum (Attribute::AttrKind). This 161 /// requires the attribute to be an enum or alignment attribute. 162 Attribute::AttrKind getKindAsEnum() const; 163 164 /// \brief Return the attribute's value as an integer. This requires that the 165 /// attribute be an alignment attribute. 166 uint64_t getValueAsInt() const; 167 168 /// \brief Return the attribute's kind as a string. This requires the 169 /// attribute to be a string attribute. 170 StringRef getKindAsString() const; 171 172 /// \brief Return the attribute's value as a string. This requires the 173 /// attribute to be a string attribute. 174 StringRef getValueAsString() const; 175 176 /// \brief Returns the alignment field of an attribute as a byte alignment 177 /// value. 178 unsigned getAlignment() const; 179 180 /// \brief Returns the stack alignment field of an attribute as a byte 181 /// alignment value. 182 unsigned getStackAlignment() const; 183 184 /// \brief Returns the number of dereferenceable bytes from the 185 /// dereferenceable attribute (or zero if unknown). 186 uint64_t getDereferenceableBytes() const; 187 188 /// \brief The Attribute is converted to a string of equivalent mnemonic. This 189 /// is, presumably, for writing out the mnemonics for the assembly writer. 190 std::string getAsString(bool InAttrGrp = false) const; 191 192 /// \brief Equality and non-equality operators. 193 bool operator==(Attribute A) const { return pImpl == A.pImpl; } 194 bool operator!=(Attribute A) const { return pImpl != A.pImpl; } 195 196 /// \brief Less-than operator. Useful for sorting the attributes list. 197 bool operator<(Attribute A) const; 198 Profile(FoldingSetNodeID & ID)199 void Profile(FoldingSetNodeID &ID) const { 200 ID.AddPointer(pImpl); 201 } 202 }; 203 204 //===----------------------------------------------------------------------===// 205 /// \class 206 /// \brief This class holds the attributes for a function, its return value, and 207 /// its parameters. You access the attributes for each of them via an index into 208 /// the AttributeSet object. The function attributes are at index 209 /// `AttributeSet::FunctionIndex', the return value is at index 210 /// `AttributeSet::ReturnIndex', and the attributes for the parameters start at 211 /// index `1'. 212 class AttributeSet { 213 public: 214 enum AttrIndex : unsigned { 215 ReturnIndex = 0U, 216 FunctionIndex = ~0U 217 }; 218 private: 219 friend class AttrBuilder; 220 friend class AttributeSetImpl; 221 template <typename Ty> friend struct DenseMapInfo; 222 223 /// \brief The attributes that we are managing. This can be null to represent 224 /// the empty attributes list. 225 AttributeSetImpl *pImpl; 226 227 /// \brief The attributes for the specified index are returned. 228 AttributeSetNode *getAttributes(unsigned Index) const; 229 230 /// \brief Create an AttributeSet with the specified parameters in it. 231 static AttributeSet get(LLVMContext &C, 232 ArrayRef<std::pair<unsigned, Attribute> > Attrs); 233 static AttributeSet get(LLVMContext &C, 234 ArrayRef<std::pair<unsigned, 235 AttributeSetNode*> > Attrs); 236 237 static AttributeSet getImpl(LLVMContext &C, 238 ArrayRef<std::pair<unsigned, 239 AttributeSetNode*> > Attrs); 240 241 AttributeSet(AttributeSetImpl * LI)242 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {} 243 public: AttributeSet()244 AttributeSet() : pImpl(nullptr) {} 245 246 //===--------------------------------------------------------------------===// 247 // AttributeSet Construction and Mutation 248 //===--------------------------------------------------------------------===// 249 250 /// \brief Return an AttributeSet with the specified parameters in it. 251 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs); 252 static AttributeSet get(LLVMContext &C, unsigned Index, 253 ArrayRef<Attribute::AttrKind> Kind); 254 static AttributeSet get(LLVMContext &C, unsigned Index, const AttrBuilder &B); 255 256 /// \brief Add an attribute to the attribute set at the given index. Since 257 /// attribute sets are immutable, this returns a new set. 258 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 259 Attribute::AttrKind Attr) const; 260 261 /// \brief Add an attribute to the attribute set at the given index. Since 262 /// attribute sets are immutable, this returns a new set. 263 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 264 StringRef Kind) const; 265 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 266 StringRef Kind, StringRef Value) const; 267 268 /// \brief Add attributes to the attribute set at the given index. Since 269 /// attribute sets are immutable, this returns a new set. 270 AttributeSet addAttributes(LLVMContext &C, unsigned Index, 271 AttributeSet Attrs) const; 272 273 /// \brief Remove the specified attribute at the specified index from this 274 /// attribute list. Since attribute lists are immutable, this returns the new 275 /// list. 276 AttributeSet removeAttribute(LLVMContext &C, unsigned Index, 277 Attribute::AttrKind Attr) const; 278 279 /// \brief Remove the specified attributes at the specified index from this 280 /// attribute list. Since attribute lists are immutable, this returns the new 281 /// list. 282 AttributeSet removeAttributes(LLVMContext &C, unsigned Index, 283 AttributeSet Attrs) const; 284 285 //===--------------------------------------------------------------------===// 286 // AttributeSet Accessors 287 //===--------------------------------------------------------------------===// 288 289 /// \brief Retrieve the LLVM context. 290 LLVMContext &getContext() const; 291 292 /// \brief The attributes for the specified index are returned. 293 AttributeSet getParamAttributes(unsigned Index) const; 294 295 /// \brief The attributes for the ret value are returned. 296 AttributeSet getRetAttributes() const; 297 298 /// \brief The function attributes are returned. 299 AttributeSet getFnAttributes() const; 300 301 /// \brief Return true if the attribute exists at the given index. 302 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const; 303 304 /// \brief Return true if the attribute exists at the given index. 305 bool hasAttribute(unsigned Index, StringRef Kind) const; 306 307 /// \brief Return true if attribute exists at the given index. 308 bool hasAttributes(unsigned Index) const; 309 310 /// \brief Return true if the specified attribute is set for at least one 311 /// parameter or for the return value. 312 bool hasAttrSomewhere(Attribute::AttrKind Attr) const; 313 314 /// \brief Return the attribute object that exists at the given index. 315 Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const; 316 317 /// \brief Return the attribute object that exists at the given index. 318 Attribute getAttribute(unsigned Index, StringRef Kind) const; 319 320 /// \brief Return the alignment for the specified function parameter. 321 unsigned getParamAlignment(unsigned Index) const; 322 323 /// \brief Get the stack alignment. 324 unsigned getStackAlignment(unsigned Index) const; 325 326 /// \brief Get the number of dereferenceable bytes (or zero if unknown). 327 uint64_t getDereferenceableBytes(unsigned Index) const; 328 329 /// \brief Return the attributes at the index as a string. 330 std::string getAsString(unsigned Index, bool InAttrGrp = false) const; 331 332 typedef ArrayRef<Attribute>::iterator iterator; 333 334 iterator begin(unsigned Slot) const; 335 iterator end(unsigned Slot) const; 336 337 /// operator==/!= - Provide equality predicates. 338 bool operator==(const AttributeSet &RHS) const { 339 return pImpl == RHS.pImpl; 340 } 341 bool operator!=(const AttributeSet &RHS) const { 342 return pImpl != RHS.pImpl; 343 } 344 345 //===--------------------------------------------------------------------===// 346 // AttributeSet Introspection 347 //===--------------------------------------------------------------------===// 348 349 // FIXME: Remove this. 350 uint64_t Raw(unsigned Index) const; 351 352 /// \brief Return a raw pointer that uniquely identifies this attribute list. getRawPointer()353 void *getRawPointer() const { 354 return pImpl; 355 } 356 357 /// \brief Return true if there are no attributes. isEmpty()358 bool isEmpty() const { 359 return getNumSlots() == 0; 360 } 361 362 /// \brief Return the number of slots used in this attribute list. This is 363 /// the number of arguments that have an attribute set on them (including the 364 /// function itself). 365 unsigned getNumSlots() const; 366 367 /// \brief Return the index for the given slot. 368 unsigned getSlotIndex(unsigned Slot) const; 369 370 /// \brief Return the attributes at the given slot. 371 AttributeSet getSlotAttributes(unsigned Slot) const; 372 373 void dump() const; 374 }; 375 376 //===----------------------------------------------------------------------===// 377 /// \class 378 /// \brief Provide DenseMapInfo for AttributeSet. 379 template<> struct DenseMapInfo<AttributeSet> { 380 static inline AttributeSet getEmptyKey() { 381 uintptr_t Val = static_cast<uintptr_t>(-1); 382 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 383 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 384 } 385 static inline AttributeSet getTombstoneKey() { 386 uintptr_t Val = static_cast<uintptr_t>(-2); 387 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 388 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 389 } 390 static unsigned getHashValue(AttributeSet AS) { 391 return (unsigned((uintptr_t)AS.pImpl) >> 4) ^ 392 (unsigned((uintptr_t)AS.pImpl) >> 9); 393 } 394 static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; } 395 }; 396 397 //===----------------------------------------------------------------------===// 398 /// \class 399 /// \brief This class is used in conjunction with the Attribute::get method to 400 /// create an Attribute object. The object itself is uniquified. The Builder's 401 /// value, however, is not. So this can be used as a quick way to test for 402 /// equality, presence of attributes, etc. 403 class AttrBuilder { 404 std::bitset<Attribute::EndAttrKinds> Attrs; 405 std::map<std::string, std::string> TargetDepAttrs; 406 uint64_t Alignment; 407 uint64_t StackAlignment; 408 uint64_t DerefBytes; 409 public: 410 AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) {} 411 explicit AttrBuilder(uint64_t Val) 412 : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) { 413 addRawValue(Val); 414 } 415 AttrBuilder(const Attribute &A) 416 : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) { 417 addAttribute(A); 418 } 419 AttrBuilder(AttributeSet AS, unsigned Idx); 420 421 void clear(); 422 423 /// \brief Add an attribute to the builder. 424 AttrBuilder &addAttribute(Attribute::AttrKind Val); 425 426 /// \brief Add the Attribute object to the builder. 427 AttrBuilder &addAttribute(Attribute A); 428 429 /// \brief Add the target-dependent attribute to the builder. 430 AttrBuilder &addAttribute(StringRef A, StringRef V = StringRef()); 431 432 /// \brief Remove an attribute from the builder. 433 AttrBuilder &removeAttribute(Attribute::AttrKind Val); 434 435 /// \brief Remove the attributes from the builder. 436 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index); 437 438 /// \brief Remove the target-dependent attribute to the builder. 439 AttrBuilder &removeAttribute(StringRef A); 440 441 /// \brief Add the attributes from the builder. 442 AttrBuilder &merge(const AttrBuilder &B); 443 444 /// \brief Return true if the builder has the specified attribute. 445 bool contains(Attribute::AttrKind A) const { 446 assert((unsigned)A < Attribute::EndAttrKinds && "Attribute out of range!"); 447 return Attrs[A]; 448 } 449 450 /// \brief Return true if the builder has the specified target-dependent 451 /// attribute. 452 bool contains(StringRef A) const; 453 454 /// \brief Return true if the builder has IR-level attributes. 455 bool hasAttributes() const; 456 457 /// \brief Return true if the builder has any attribute that's in the 458 /// specified attribute. 459 bool hasAttributes(AttributeSet A, uint64_t Index) const; 460 461 /// \brief Return true if the builder has an alignment attribute. 462 bool hasAlignmentAttr() const; 463 464 /// \brief Retrieve the alignment attribute, if it exists. 465 uint64_t getAlignment() const { return Alignment; } 466 467 /// \brief Retrieve the stack alignment attribute, if it exists. 468 uint64_t getStackAlignment() const { return StackAlignment; } 469 470 /// \brief Retrieve the number of dereferenceable bytes, if the dereferenceable 471 /// attribute exists (zero is returned otherwise). 472 uint64_t getDereferenceableBytes() const { return DerefBytes; } 473 474 /// \brief This turns an int alignment (which must be a power of 2) into the 475 /// form used internally in Attribute. 476 AttrBuilder &addAlignmentAttr(unsigned Align); 477 478 /// \brief This turns an int stack alignment (which must be a power of 2) into 479 /// the form used internally in Attribute. 480 AttrBuilder &addStackAlignmentAttr(unsigned Align); 481 482 /// \brief This turns the number of dereferenceable bytes into the form used 483 /// internally in Attribute. 484 AttrBuilder &addDereferenceableAttr(uint64_t Bytes); 485 486 /// \brief Return true if the builder contains no target-independent 487 /// attributes. 488 bool empty() const { return Attrs.none(); } 489 490 // Iterators for target-dependent attributes. 491 typedef std::pair<std::string, std::string> td_type; 492 typedef std::map<std::string, std::string>::iterator td_iterator; 493 typedef std::map<std::string, std::string>::const_iterator td_const_iterator; 494 typedef llvm::iterator_range<td_iterator> td_range; 495 typedef llvm::iterator_range<td_const_iterator> td_const_range; 496 497 td_iterator td_begin() { return TargetDepAttrs.begin(); } 498 td_iterator td_end() { return TargetDepAttrs.end(); } 499 500 td_const_iterator td_begin() const { return TargetDepAttrs.begin(); } 501 td_const_iterator td_end() const { return TargetDepAttrs.end(); } 502 503 td_range td_attrs() { return td_range(td_begin(), td_end()); } 504 td_const_range td_attrs() const { 505 return td_const_range(td_begin(), td_end()); 506 } 507 508 bool td_empty() const { return TargetDepAttrs.empty(); } 509 510 bool operator==(const AttrBuilder &B); 511 bool operator!=(const AttrBuilder &B) { 512 return !(*this == B); 513 } 514 515 // FIXME: Remove this in 4.0. 516 517 /// \brief Add the raw value to the internal representation. 518 AttrBuilder &addRawValue(uint64_t Val); 519 }; 520 521 namespace AttributeFuncs { 522 523 /// \brief Which attributes cannot be applied to a type. 524 AttributeSet typeIncompatible(Type *Ty, uint64_t Index); 525 526 } // end AttributeFuncs namespace 527 528 } // end llvm namespace 529 530 #endif 531