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