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 DereferenceableOrNull, ///< Pointer is either null or dereferenceable 93 NoRedZone, ///< Disable redzone 94 NoReturn, ///< Mark the function as not returning 95 NoUnwind, ///< Function doesn't unwind stack 96 OptimizeForSize, ///< opt_size 97 OptimizeNone, ///< Function must not be optimized. 98 ReadNone, ///< Function does not access memory 99 ReadOnly, ///< Function only reads from memory 100 Returned, ///< Return value is always equal to this argument 101 ReturnsTwice, ///< Function can return twice 102 SExt, ///< Sign extended before/after call 103 StackAlignment, ///< Alignment of stack for function (3 bits) 104 ///< stored as log2 of alignment with +1 bias 0 105 ///< means unaligned (different from 106 ///< alignstack=(1)) 107 StackProtect, ///< Stack protection. 108 StackProtectReq, ///< Stack protection required. 109 StackProtectStrong, ///< Strong Stack protection. 110 StructRet, ///< Hidden pointer to structure to return 111 SanitizeAddress, ///< AddressSanitizer is on. 112 SanitizeThread, ///< ThreadSanitizer is on. 113 SanitizeMemory, ///< MemorySanitizer is on. 114 UWTable, ///< Function must be in a unwind table 115 ZExt, ///< Zero extended before/after call 116 117 EndAttrKinds ///< Sentinal value useful for loops 118 }; 119 private: 120 AttributeImpl *pImpl; 121 Attribute(AttributeImpl *A) : pImpl(A) {} 122 public: 123 Attribute() : pImpl(nullptr) {} 124 125 //===--------------------------------------------------------------------===// 126 // Attribute Construction 127 //===--------------------------------------------------------------------===// 128 129 /// \brief Return a uniquified Attribute object. 130 static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0); 131 static Attribute get(LLVMContext &Context, StringRef Kind, 132 StringRef Val = StringRef()); 133 134 /// \brief Return a uniquified Attribute object that has the specific 135 /// alignment set. 136 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align); 137 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align); 138 static Attribute getWithDereferenceableBytes(LLVMContext &Context, 139 uint64_t Bytes); 140 static Attribute getWithDereferenceableOrNullBytes(LLVMContext &Context, 141 uint64_t Bytes); 142 143 //===--------------------------------------------------------------------===// 144 // Attribute Accessors 145 //===--------------------------------------------------------------------===// 146 147 /// \brief Return true if the attribute is an Attribute::AttrKind type. 148 bool isEnumAttribute() const; 149 150 /// \brief Return true if the attribute is an integer attribute. 151 bool isIntAttribute() const; 152 153 /// \brief Return true if the attribute is a string (target-dependent) 154 /// attribute. 155 bool isStringAttribute() const; 156 157 /// \brief Return true if the attribute is present. 158 bool hasAttribute(AttrKind Val) const; 159 160 /// \brief Return true if the target-dependent attribute is present. 161 bool hasAttribute(StringRef Val) const; 162 163 /// \brief Return the attribute's kind as an enum (Attribute::AttrKind). This 164 /// requires the attribute to be an enum or alignment attribute. 165 Attribute::AttrKind getKindAsEnum() const; 166 167 /// \brief Return the attribute's value as an integer. This requires that the 168 /// attribute be an alignment attribute. 169 uint64_t getValueAsInt() const; 170 171 /// \brief Return the attribute's kind as a string. This requires the 172 /// attribute to be a string attribute. 173 StringRef getKindAsString() const; 174 175 /// \brief Return the attribute's value as a string. This requires the 176 /// attribute to be a string attribute. 177 StringRef getValueAsString() const; 178 179 /// \brief Returns the alignment field of an attribute as a byte alignment 180 /// value. 181 unsigned getAlignment() const; 182 183 /// \brief Returns the stack alignment field of an attribute as a byte 184 /// alignment value. 185 unsigned getStackAlignment() const; 186 187 /// \brief Returns the number of dereferenceable bytes from the 188 /// dereferenceable attribute (or zero if unknown). 189 uint64_t getDereferenceableBytes() const; 190 191 /// \brief Returns the number of dereferenceable_or_null bytes from the 192 /// dereferenceable_or_null attribute (or zero if unknown). 193 uint64_t getDereferenceableOrNullBytes() const; 194 195 /// \brief The Attribute is converted to a string of equivalent mnemonic. This 196 /// is, presumably, for writing out the mnemonics for the assembly writer. 197 std::string getAsString(bool InAttrGrp = false) const; 198 199 /// \brief Equality and non-equality operators. 200 bool operator==(Attribute A) const { return pImpl == A.pImpl; } 201 bool operator!=(Attribute A) const { return pImpl != A.pImpl; } 202 203 /// \brief Less-than operator. Useful for sorting the attributes list. 204 bool operator<(Attribute A) const; 205 206 void Profile(FoldingSetNodeID &ID) const { 207 ID.AddPointer(pImpl); 208 } 209 }; 210 211 //===----------------------------------------------------------------------===// 212 /// \class 213 /// \brief This class holds the attributes for a function, its return value, and 214 /// its parameters. You access the attributes for each of them via an index into 215 /// the AttributeSet object. The function attributes are at index 216 /// `AttributeSet::FunctionIndex', the return value is at index 217 /// `AttributeSet::ReturnIndex', and the attributes for the parameters start at 218 /// index `1'. 219 class AttributeSet { 220 public: 221 enum AttrIndex : unsigned { 222 ReturnIndex = 0U, 223 FunctionIndex = ~0U 224 }; 225 private: 226 friend class AttrBuilder; 227 friend class AttributeSetImpl; 228 template <typename Ty> friend struct DenseMapInfo; 229 230 /// \brief The attributes that we are managing. This can be null to represent 231 /// the empty attributes list. 232 AttributeSetImpl *pImpl; 233 234 /// \brief The attributes for the specified index are returned. 235 AttributeSetNode *getAttributes(unsigned Index) const; 236 237 /// \brief Create an AttributeSet with the specified parameters in it. 238 static AttributeSet get(LLVMContext &C, 239 ArrayRef<std::pair<unsigned, Attribute> > Attrs); 240 static AttributeSet get(LLVMContext &C, 241 ArrayRef<std::pair<unsigned, 242 AttributeSetNode*> > Attrs); 243 244 static AttributeSet getImpl(LLVMContext &C, 245 ArrayRef<std::pair<unsigned, 246 AttributeSetNode*> > Attrs); 247 248 249 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {} 250 public: 251 AttributeSet() : pImpl(nullptr) {} 252 253 //===--------------------------------------------------------------------===// 254 // AttributeSet Construction and Mutation 255 //===--------------------------------------------------------------------===// 256 257 /// \brief Return an AttributeSet with the specified parameters in it. 258 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs); 259 static AttributeSet get(LLVMContext &C, unsigned Index, 260 ArrayRef<Attribute::AttrKind> Kind); 261 static AttributeSet get(LLVMContext &C, unsigned Index, const AttrBuilder &B); 262 263 /// \brief Add an attribute to the attribute set at the given index. Since 264 /// attribute sets are immutable, this returns a new set. 265 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 266 Attribute::AttrKind Attr) const; 267 268 /// \brief Add an attribute to the attribute set at the given index. Since 269 /// attribute sets are immutable, this returns a new set. 270 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 271 StringRef Kind) const; 272 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 273 StringRef Kind, StringRef Value) const; 274 275 /// \brief Add attributes to the attribute set at the given index. Since 276 /// attribute sets are immutable, this returns a new set. 277 AttributeSet addAttributes(LLVMContext &C, unsigned Index, 278 AttributeSet Attrs) const; 279 280 /// \brief Remove the specified attribute at the specified index from this 281 /// attribute list. Since attribute lists are immutable, this returns the new 282 /// list. 283 AttributeSet removeAttribute(LLVMContext &C, unsigned Index, 284 Attribute::AttrKind Attr) const; 285 286 /// \brief Remove the specified attributes at the specified index from this 287 /// attribute list. Since attribute lists are immutable, this returns the new 288 /// list. 289 AttributeSet removeAttributes(LLVMContext &C, unsigned Index, 290 AttributeSet Attrs) const; 291 292 /// \brief Add the dereferenceable attribute to the attribute set at the given 293 /// index. Since attribute sets are immutable, this returns a new set. 294 AttributeSet addDereferenceableAttr(LLVMContext &C, unsigned Index, 295 uint64_t Bytes) const; 296 297 /// \brief Add the dereferenceable_or_null attribute to the attribute set at 298 /// the given index. Since attribute sets are immutable, this returns a new 299 /// set. 300 AttributeSet addDereferenceableOrNullAttr(LLVMContext &C, unsigned Index, 301 uint64_t Bytes) const; 302 303 //===--------------------------------------------------------------------===// 304 // AttributeSet Accessors 305 //===--------------------------------------------------------------------===// 306 307 /// \brief Retrieve the LLVM context. 308 LLVMContext &getContext() const; 309 310 /// \brief The attributes for the specified index are returned. 311 AttributeSet getParamAttributes(unsigned Index) const; 312 313 /// \brief The attributes for the ret value are returned. 314 AttributeSet getRetAttributes() const; 315 316 /// \brief The function attributes are returned. 317 AttributeSet getFnAttributes() const; 318 319 /// \brief Return true if the attribute exists at the given index. 320 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const; 321 322 /// \brief Return true if the attribute exists at the given index. 323 bool hasAttribute(unsigned Index, StringRef Kind) const; 324 325 /// \brief Return true if attribute exists at the given index. 326 bool hasAttributes(unsigned Index) const; 327 328 /// \brief Return true if the specified attribute is set for at least one 329 /// parameter or for the return value. 330 bool hasAttrSomewhere(Attribute::AttrKind Attr) const; 331 332 /// \brief Return the attribute object that exists at the given index. 333 Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const; 334 335 /// \brief Return the attribute object that exists at the given index. 336 Attribute getAttribute(unsigned Index, StringRef Kind) const; 337 338 /// \brief Return the alignment for the specified function parameter. 339 unsigned getParamAlignment(unsigned Index) const; 340 341 /// \brief Get the stack alignment. 342 unsigned getStackAlignment(unsigned Index) const; 343 344 /// \brief Get the number of dereferenceable bytes (or zero if unknown). 345 uint64_t getDereferenceableBytes(unsigned Index) const; 346 347 /// \brief Get the number of dereferenceable_or_null bytes (or zero if 348 /// unknown). 349 uint64_t getDereferenceableOrNullBytes(unsigned Index) const; 350 351 /// \brief Return the attributes at the index as a string. 352 std::string getAsString(unsigned Index, bool InAttrGrp = false) const; 353 354 typedef ArrayRef<Attribute>::iterator iterator; 355 356 iterator begin(unsigned Slot) const; 357 iterator end(unsigned Slot) const; 358 359 /// operator==/!= - Provide equality predicates. 360 bool operator==(const AttributeSet &RHS) const { 361 return pImpl == RHS.pImpl; 362 } 363 bool operator!=(const AttributeSet &RHS) const { 364 return pImpl != RHS.pImpl; 365 } 366 367 //===--------------------------------------------------------------------===// 368 // AttributeSet Introspection 369 //===--------------------------------------------------------------------===// 370 371 // FIXME: Remove this. 372 uint64_t Raw(unsigned Index) const; 373 374 /// \brief Return a raw pointer that uniquely identifies this attribute list. 375 void *getRawPointer() const { 376 return pImpl; 377 } 378 379 /// \brief Return true if there are no attributes. 380 bool isEmpty() const { 381 return getNumSlots() == 0; 382 } 383 384 /// \brief Return the number of slots used in this attribute list. This is 385 /// the number of arguments that have an attribute set on them (including the 386 /// function itself). 387 unsigned getNumSlots() const; 388 389 /// \brief Return the index for the given slot. 390 unsigned getSlotIndex(unsigned Slot) const; 391 392 /// \brief Return the attributes at the given slot. 393 AttributeSet getSlotAttributes(unsigned Slot) const; 394 395 void dump() const; 396 }; 397 398 //===----------------------------------------------------------------------===// 399 /// \class 400 /// \brief Provide DenseMapInfo for AttributeSet. 401 template<> struct DenseMapInfo<AttributeSet> { 402 static inline AttributeSet getEmptyKey() { 403 uintptr_t Val = static_cast<uintptr_t>(-1); 404 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 405 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 406 } 407 static inline AttributeSet getTombstoneKey() { 408 uintptr_t Val = static_cast<uintptr_t>(-2); 409 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 410 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 411 } 412 static unsigned getHashValue(AttributeSet AS) { 413 return (unsigned((uintptr_t)AS.pImpl) >> 4) ^ 414 (unsigned((uintptr_t)AS.pImpl) >> 9); 415 } 416 static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; } 417 }; 418 419 //===----------------------------------------------------------------------===// 420 /// \class 421 /// \brief This class is used in conjunction with the Attribute::get method to 422 /// create an Attribute object. The object itself is uniquified. The Builder's 423 /// value, however, is not. So this can be used as a quick way to test for 424 /// equality, presence of attributes, etc. 425 class AttrBuilder { 426 std::bitset<Attribute::EndAttrKinds> Attrs; 427 std::map<std::string, std::string> TargetDepAttrs; 428 uint64_t Alignment; 429 uint64_t StackAlignment; 430 uint64_t DerefBytes; 431 uint64_t DerefOrNullBytes; 432 public: 433 AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) {} 434 explicit AttrBuilder(uint64_t Val) 435 : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) { 436 addRawValue(Val); 437 } 438 AttrBuilder(const Attribute &A) 439 : Attrs(0), Alignment(0), StackAlignment(0), DerefBytes(0) { 440 addAttribute(A); 441 } 442 AttrBuilder(AttributeSet AS, unsigned Idx); 443 444 void clear(); 445 446 /// \brief Add an attribute to the builder. 447 AttrBuilder &addAttribute(Attribute::AttrKind Val); 448 449 /// \brief Add the Attribute object to the builder. 450 AttrBuilder &addAttribute(Attribute A); 451 452 /// \brief Add the target-dependent attribute to the builder. 453 AttrBuilder &addAttribute(StringRef A, StringRef V = StringRef()); 454 455 /// \brief Remove an attribute from the builder. 456 AttrBuilder &removeAttribute(Attribute::AttrKind Val); 457 458 /// \brief Remove the attributes from the builder. 459 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index); 460 461 /// \brief Remove the target-dependent attribute to the builder. 462 AttrBuilder &removeAttribute(StringRef A); 463 464 /// \brief Add the attributes from the builder. 465 AttrBuilder &merge(const AttrBuilder &B); 466 467 /// \brief Return true if the builder has the specified attribute. 468 bool contains(Attribute::AttrKind A) const { 469 assert((unsigned)A < Attribute::EndAttrKinds && "Attribute out of range!"); 470 return Attrs[A]; 471 } 472 473 /// \brief Return true if the builder has the specified target-dependent 474 /// attribute. 475 bool contains(StringRef A) const; 476 477 /// \brief Return true if the builder has IR-level attributes. 478 bool hasAttributes() const; 479 480 /// \brief Return true if the builder has any attribute that's in the 481 /// specified attribute. 482 bool hasAttributes(AttributeSet A, uint64_t Index) const; 483 484 /// \brief Return true if the builder has an alignment attribute. 485 bool hasAlignmentAttr() const; 486 487 /// \brief Retrieve the alignment attribute, if it exists. 488 uint64_t getAlignment() const { return Alignment; } 489 490 /// \brief Retrieve the stack alignment attribute, if it exists. 491 uint64_t getStackAlignment() const { return StackAlignment; } 492 493 /// \brief Retrieve the number of dereferenceable bytes, if the dereferenceable 494 /// attribute exists (zero is returned otherwise). 495 uint64_t getDereferenceableBytes() const { return DerefBytes; } 496 497 /// \brief Retrieve the number of dereferenceable_or_null bytes, if the 498 /// dereferenceable_or_null attribute exists (zero is returned otherwise). 499 uint64_t getDereferenceableOrNullBytes() const { return DerefOrNullBytes; } 500 501 /// \brief This turns an int alignment (which must be a power of 2) into the 502 /// form used internally in Attribute. 503 AttrBuilder &addAlignmentAttr(unsigned Align); 504 505 /// \brief This turns an int stack alignment (which must be a power of 2) into 506 /// the form used internally in Attribute. 507 AttrBuilder &addStackAlignmentAttr(unsigned Align); 508 509 /// \brief This turns the number of dereferenceable bytes into the form used 510 /// internally in Attribute. 511 AttrBuilder &addDereferenceableAttr(uint64_t Bytes); 512 513 /// \brief This turns the number of dereferenceable_or_null bytes into the 514 /// form used internally in Attribute. 515 AttrBuilder &addDereferenceableOrNullAttr(uint64_t Bytes); 516 517 /// \brief Return true if the builder contains no target-independent 518 /// attributes. 519 bool empty() const { return Attrs.none(); } 520 521 // Iterators for target-dependent attributes. 522 typedef std::pair<std::string, std::string> td_type; 523 typedef std::map<std::string, std::string>::iterator td_iterator; 524 typedef std::map<std::string, std::string>::const_iterator td_const_iterator; 525 typedef llvm::iterator_range<td_iterator> td_range; 526 typedef llvm::iterator_range<td_const_iterator> td_const_range; 527 528 td_iterator td_begin() { return TargetDepAttrs.begin(); } 529 td_iterator td_end() { return TargetDepAttrs.end(); } 530 531 td_const_iterator td_begin() const { return TargetDepAttrs.begin(); } 532 td_const_iterator td_end() const { return TargetDepAttrs.end(); } 533 534 td_range td_attrs() { return td_range(td_begin(), td_end()); } 535 td_const_range td_attrs() const { 536 return td_const_range(td_begin(), td_end()); 537 } 538 539 bool td_empty() const { return TargetDepAttrs.empty(); } 540 541 bool operator==(const AttrBuilder &B); 542 bool operator!=(const AttrBuilder &B) { 543 return !(*this == B); 544 } 545 546 // FIXME: Remove this in 4.0. 547 548 /// \brief Add the raw value to the internal representation. 549 AttrBuilder &addRawValue(uint64_t Val); 550 }; 551 552 namespace AttributeFuncs { 553 554 /// \brief Which attributes cannot be applied to a type. 555 AttributeSet typeIncompatible(Type *Ty, uint64_t Index); 556 557 } // end AttributeFuncs namespace 558 559 } // end llvm namespace 560 561 #endif 562
