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 NoRedZone, ///< Disable redzone 92 NoReturn, ///< Mark the function as not returning 93 NoUnwind, ///< Function doesn't unwind stack 94 OptimizeForSize, ///< opt_size 95 OptimizeNone, ///< Function must not be optimized. 96 ReadNone, ///< Function does not access memory 97 ReadOnly, ///< Function only reads from memory 98 Returned, ///< Return value is always equal to this argument 99 ReturnsTwice, ///< Function can return twice 100 SExt, ///< Sign extended before/after call 101 StackAlignment, ///< Alignment of stack for function (3 bits) 102 ///< stored as log2 of alignment with +1 bias 0 103 ///< means unaligned (different from 104 ///< alignstack=(1)) 105 StackProtect, ///< Stack protection. 106 StackProtectReq, ///< Stack protection required. 107 StackProtectStrong, ///< Strong Stack protection. 108 StructRet, ///< Hidden pointer to structure to return 109 SanitizeAddress, ///< AddressSanitizer is on. 110 SanitizeThread, ///< ThreadSanitizer is on. 111 SanitizeMemory, ///< MemorySanitizer is on. 112 UWTable, ///< Function must be in a unwind table 113 ZExt, ///< Zero extended before/after call 114 115 EndAttrKinds ///< Sentinal value useful for loops 116 }; 117 private: 118 AttributeImpl *pImpl; 119 Attribute(AttributeImpl *A) : pImpl(A) {} 120 public: 121 Attribute() : pImpl(nullptr) {} 122 123 //===--------------------------------------------------------------------===// 124 // Attribute Construction 125 //===--------------------------------------------------------------------===// 126 127 /// \brief Return a uniquified Attribute object. 128 static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0); 129 static Attribute get(LLVMContext &Context, StringRef Kind, 130 StringRef Val = StringRef()); 131 132 /// \brief Return a uniquified Attribute object that has the specific 133 /// alignment set. 134 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align); 135 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align); 136 137 //===--------------------------------------------------------------------===// 138 // Attribute Accessors 139 //===--------------------------------------------------------------------===// 140 141 /// \brief Return true if the attribute is an Attribute::AttrKind type. 142 bool isEnumAttribute() const; 143 144 /// \brief Return true if the attribute is an alignment attribute. 145 bool isAlignAttribute() const; 146 147 /// \brief Return true if the attribute is a string (target-dependent) 148 /// attribute. 149 bool isStringAttribute() const; 150 151 /// \brief Return true if the attribute is present. 152 bool hasAttribute(AttrKind Val) const; 153 154 /// \brief Return true if the target-dependent attribute is present. 155 bool hasAttribute(StringRef Val) const; 156 157 /// \brief Return the attribute's kind as an enum (Attribute::AttrKind). This 158 /// requires the attribute to be an enum or alignment attribute. 159 Attribute::AttrKind getKindAsEnum() const; 160 161 /// \brief Return the attribute's value as an integer. This requires that the 162 /// attribute be an alignment attribute. 163 uint64_t getValueAsInt() const; 164 165 /// \brief Return the attribute's kind as a string. This requires the 166 /// attribute to be a string attribute. 167 StringRef getKindAsString() const; 168 169 /// \brief Return the attribute's value as a string. This requires the 170 /// attribute to be a string attribute. 171 StringRef getValueAsString() const; 172 173 /// \brief Returns the alignment field of an attribute as a byte alignment 174 /// value. 175 unsigned getAlignment() const; 176 177 /// \brief Returns the stack alignment field of an attribute as a byte 178 /// alignment value. 179 unsigned getStackAlignment() const; 180 181 /// \brief The Attribute is converted to a string of equivalent mnemonic. This 182 /// is, presumably, for writing out the mnemonics for the assembly writer. 183 std::string getAsString(bool InAttrGrp = false) const; 184 185 /// \brief Equality and non-equality operators. 186 bool operator==(Attribute A) const { return pImpl == A.pImpl; } 187 bool operator!=(Attribute A) const { return pImpl != A.pImpl; } 188 189 /// \brief Less-than operator. Useful for sorting the attributes list. 190 bool operator<(Attribute A) const; 191 192 void Profile(FoldingSetNodeID &ID) const { 193 ID.AddPointer(pImpl); 194 } 195 }; 196 197 //===----------------------------------------------------------------------===// 198 /// \class 199 /// \brief This class holds the attributes for a function, its return value, and 200 /// its parameters. You access the attributes for each of them via an index into 201 /// the AttributeSet object. The function attributes are at index 202 /// `AttributeSet::FunctionIndex', the return value is at index 203 /// `AttributeSet::ReturnIndex', and the attributes for the parameters start at 204 /// index `1'. 205 class AttributeSet { 206 public: 207 enum AttrIndex : unsigned { 208 ReturnIndex = 0U, 209 FunctionIndex = ~0U 210 }; 211 private: 212 friend class AttrBuilder; 213 friend class AttributeSetImpl; 214 template <typename Ty> friend struct DenseMapInfo; 215 216 /// \brief The attributes that we are managing. This can be null to represent 217 /// the empty attributes list. 218 AttributeSetImpl *pImpl; 219 220 /// \brief The attributes for the specified index are returned. 221 AttributeSetNode *getAttributes(unsigned Index) const; 222 223 /// \brief Create an AttributeSet with the specified parameters in it. 224 static AttributeSet get(LLVMContext &C, 225 ArrayRef<std::pair<unsigned, Attribute> > Attrs); 226 static AttributeSet get(LLVMContext &C, 227 ArrayRef<std::pair<unsigned, 228 AttributeSetNode*> > Attrs); 229 230 static AttributeSet getImpl(LLVMContext &C, 231 ArrayRef<std::pair<unsigned, 232 AttributeSetNode*> > Attrs); 233 234 235 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {} 236 public: 237 AttributeSet() : pImpl(nullptr) {} 238 239 //===--------------------------------------------------------------------===// 240 // AttributeSet Construction and Mutation 241 //===--------------------------------------------------------------------===// 242 243 /// \brief Return an AttributeSet with the specified parameters in it. 244 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs); 245 static AttributeSet get(LLVMContext &C, unsigned Index, 246 ArrayRef<Attribute::AttrKind> Kind); 247 static AttributeSet get(LLVMContext &C, unsigned Index, const AttrBuilder &B); 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 Attribute::AttrKind Attr) const; 253 254 /// \brief Add an attribute to the attribute set at the given index. Since 255 /// attribute sets are immutable, this returns a new set. 256 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 257 StringRef Kind) const; 258 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 259 StringRef Kind, StringRef Value) const; 260 261 /// \brief Add attributes to the attribute set at the given index. Since 262 /// attribute sets are immutable, this returns a new set. 263 AttributeSet addAttributes(LLVMContext &C, unsigned Index, 264 AttributeSet Attrs) const; 265 266 /// \brief Remove the specified attribute at the specified index from this 267 /// attribute list. Since attribute lists are immutable, this returns the new 268 /// list. 269 AttributeSet removeAttribute(LLVMContext &C, unsigned Index, 270 Attribute::AttrKind Attr) const; 271 272 /// \brief Remove the specified attributes at the specified index from this 273 /// attribute list. Since attribute lists are immutable, this returns the new 274 /// list. 275 AttributeSet removeAttributes(LLVMContext &C, unsigned Index, 276 AttributeSet Attrs) const; 277 278 //===--------------------------------------------------------------------===// 279 // AttributeSet Accessors 280 //===--------------------------------------------------------------------===// 281 282 /// \brief Retrieve the LLVM context. 283 LLVMContext &getContext() const; 284 285 /// \brief The attributes for the specified index are returned. 286 AttributeSet getParamAttributes(unsigned Index) const; 287 288 /// \brief The attributes for the ret value are returned. 289 AttributeSet getRetAttributes() const; 290 291 /// \brief The function attributes are returned. 292 AttributeSet getFnAttributes() const; 293 294 /// \brief Return true if the attribute exists at the given index. 295 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const; 296 297 /// \brief Return true if the attribute exists at the given index. 298 bool hasAttribute(unsigned Index, StringRef Kind) const; 299 300 /// \brief Return true if attribute exists at the given index. 301 bool hasAttributes(unsigned Index) const; 302 303 /// \brief Return true if the specified attribute is set for at least one 304 /// parameter or for the return value. 305 bool hasAttrSomewhere(Attribute::AttrKind Attr) const; 306 307 /// \brief Return the attribute object that exists at the given index. 308 Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const; 309 310 /// \brief Return the attribute object that exists at the given index. 311 Attribute getAttribute(unsigned Index, StringRef Kind) const; 312 313 /// \brief Return the alignment for the specified function parameter. 314 unsigned getParamAlignment(unsigned Index) const; 315 316 /// \brief Get the stack alignment. 317 unsigned getStackAlignment(unsigned Index) const; 318 319 /// \brief Return the attributes at the index as a string. 320 std::string getAsString(unsigned Index, bool InAttrGrp = false) const; 321 322 typedef ArrayRef<Attribute>::iterator iterator; 323 324 iterator begin(unsigned Slot) const; 325 iterator end(unsigned Slot) const; 326 327 /// operator==/!= - Provide equality predicates. 328 bool operator==(const AttributeSet &RHS) const { 329 return pImpl == RHS.pImpl; 330 } 331 bool operator!=(const AttributeSet &RHS) const { 332 return pImpl != RHS.pImpl; 333 } 334 335 //===--------------------------------------------------------------------===// 336 // AttributeSet Introspection 337 //===--------------------------------------------------------------------===// 338 339 // FIXME: Remove this. 340 uint64_t Raw(unsigned Index) const; 341 342 /// \brief Return a raw pointer that uniquely identifies this attribute list. 343 void *getRawPointer() const { 344 return pImpl; 345 } 346 347 /// \brief Return true if there are no attributes. 348 bool isEmpty() const { 349 return getNumSlots() == 0; 350 } 351 352 /// \brief Return the number of slots used in this attribute list. This is 353 /// the number of arguments that have an attribute set on them (including the 354 /// function itself). 355 unsigned getNumSlots() const; 356 357 /// \brief Return the index for the given slot. 358 unsigned getSlotIndex(unsigned Slot) const; 359 360 /// \brief Return the attributes at the given slot. 361 AttributeSet getSlotAttributes(unsigned Slot) const; 362 363 void dump() const; 364 }; 365 366 //===----------------------------------------------------------------------===// 367 /// \class 368 /// \brief Provide DenseMapInfo for AttributeSet. 369 template<> struct DenseMapInfo<AttributeSet> { 370 static inline AttributeSet getEmptyKey() { 371 uintptr_t Val = static_cast<uintptr_t>(-1); 372 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 373 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 374 } 375 static inline AttributeSet getTombstoneKey() { 376 uintptr_t Val = static_cast<uintptr_t>(-2); 377 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 378 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 379 } 380 static unsigned getHashValue(AttributeSet AS) { 381 return (unsigned((uintptr_t)AS.pImpl) >> 4) ^ 382 (unsigned((uintptr_t)AS.pImpl) >> 9); 383 } 384 static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; } 385 }; 386 387 //===----------------------------------------------------------------------===// 388 /// \class 389 /// \brief This class is used in conjunction with the Attribute::get method to 390 /// create an Attribute object. The object itself is uniquified. The Builder's 391 /// value, however, is not. So this can be used as a quick way to test for 392 /// equality, presence of attributes, etc. 393 class AttrBuilder { 394 std::bitset<Attribute::EndAttrKinds> Attrs; 395 std::map<std::string, std::string> TargetDepAttrs; 396 uint64_t Alignment; 397 uint64_t StackAlignment; 398 public: 399 AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0) {} 400 explicit AttrBuilder(uint64_t Val) 401 : Attrs(0), Alignment(0), StackAlignment(0) { 402 addRawValue(Val); 403 } 404 AttrBuilder(const Attribute &A) : Attrs(0), Alignment(0), StackAlignment(0) { 405 addAttribute(A); 406 } 407 AttrBuilder(AttributeSet AS, unsigned Idx); 408 409 void clear(); 410 411 /// \brief Add an attribute to the builder. 412 AttrBuilder &addAttribute(Attribute::AttrKind Val); 413 414 /// \brief Add the Attribute object to the builder. 415 AttrBuilder &addAttribute(Attribute A); 416 417 /// \brief Add the target-dependent attribute to the builder. 418 AttrBuilder &addAttribute(StringRef A, StringRef V = StringRef()); 419 420 /// \brief Remove an attribute from the builder. 421 AttrBuilder &removeAttribute(Attribute::AttrKind Val); 422 423 /// \brief Remove the attributes from the builder. 424 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index); 425 426 /// \brief Remove the target-dependent attribute to the builder. 427 AttrBuilder &removeAttribute(StringRef A); 428 429 /// \brief Add the attributes from the builder. 430 AttrBuilder &merge(const AttrBuilder &B); 431 432 /// \brief Return true if the builder has the specified attribute. 433 bool contains(Attribute::AttrKind A) const { 434 assert((unsigned)A < Attribute::EndAttrKinds && "Attribute out of range!"); 435 return Attrs[A]; 436 } 437 438 /// \brief Return true if the builder has the specified target-dependent 439 /// attribute. 440 bool contains(StringRef A) const; 441 442 /// \brief Return true if the builder has IR-level attributes. 443 bool hasAttributes() const; 444 445 /// \brief Return true if the builder has any attribute that's in the 446 /// specified attribute. 447 bool hasAttributes(AttributeSet A, uint64_t Index) const; 448 449 /// \brief Return true if the builder has an alignment attribute. 450 bool hasAlignmentAttr() const; 451 452 /// \brief Retrieve the alignment attribute, if it exists. 453 uint64_t getAlignment() const { return Alignment; } 454 455 /// \brief Retrieve the stack alignment attribute, if it exists. 456 uint64_t getStackAlignment() const { return StackAlignment; } 457 458 /// \brief This turns an int alignment (which must be a power of 2) into the 459 /// form used internally in Attribute. 460 AttrBuilder &addAlignmentAttr(unsigned Align); 461 462 /// \brief This turns an int stack alignment (which must be a power of 2) into 463 /// the form used internally in Attribute. 464 AttrBuilder &addStackAlignmentAttr(unsigned Align); 465 466 /// \brief Return true if the builder contains no target-independent 467 /// attributes. 468 bool empty() const { return Attrs.none(); } 469 470 // Iterators for target-dependent attributes. 471 typedef std::pair<std::string, std::string> td_type; 472 typedef std::map<std::string, std::string>::iterator td_iterator; 473 typedef std::map<std::string, std::string>::const_iterator td_const_iterator; 474 typedef llvm::iterator_range<td_iterator> td_range; 475 typedef llvm::iterator_range<td_const_iterator> td_const_range; 476 477 td_iterator td_begin() { return TargetDepAttrs.begin(); } 478 td_iterator td_end() { return TargetDepAttrs.end(); } 479 480 td_const_iterator td_begin() const { return TargetDepAttrs.begin(); } 481 td_const_iterator td_end() const { return TargetDepAttrs.end(); } 482 483 td_range td_attrs() { return td_range(td_begin(), td_end()); } 484 td_const_range td_attrs() const { 485 return td_const_range(td_begin(), td_end()); 486 } 487 488 bool td_empty() const { return TargetDepAttrs.empty(); } 489 490 bool operator==(const AttrBuilder &B); 491 bool operator!=(const AttrBuilder &B) { 492 return !(*this == B); 493 } 494 495 // FIXME: Remove this in 4.0. 496 497 /// \brief Add the raw value to the internal representation. 498 AttrBuilder &addRawValue(uint64_t Val); 499 }; 500 501 namespace AttributeFuncs { 502 503 /// \brief Which attributes cannot be applied to a type. 504 AttributeSet typeIncompatible(Type *Ty, uint64_t Index); 505 506 } // end AttributeFuncs namespace 507 508 } // end llvm namespace 509 510 #endif 511
