Attributes.h revision 76f103e02164d27b41bd92a9767c7012482ba31a
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 27namespace llvm { 28 29class AttrBuilder; 30class AttributeImpl; 31class AttributeSetImpl; 32class AttributeSetNode; 33class Constant; 34template<typename T> struct DenseMapInfo; 35class LLVMContext; 36class 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. 44class Attribute { 45public: 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 Returned, ///< Return value is always equal to this argument 91 ReturnsTwice, ///< Function can return twice 92 SExt, ///< Sign extended before/after call 93 StackAlignment, ///< Alignment of stack for function (3 bits) 94 ///< stored as log2 of alignment with +1 bias 0 95 ///< means unaligned (different from 96 ///< alignstack=(1)) 97 StackProtect, ///< Stack protection. 98 StackProtectReq, ///< Stack protection required. 99 StackProtectStrong, ///< Strong Stack protection. 100 StructRet, ///< Hidden pointer to structure to return 101 SanitizeAddress, ///< AddressSanitizer is on. 102 SanitizeThread, ///< ThreadSanitizer is on. 103 SanitizeMemory, ///< MemorySanitizer is on. 104 UWTable, ///< Function must be in a unwind table 105 ZExt, ///< Zero extended before/after call 106 107 EndAttrKinds ///< Sentinal value useful for loops 108 }; 109private: 110 AttributeImpl *pImpl; 111 Attribute(AttributeImpl *A) : pImpl(A) {} 112public: 113 Attribute() : pImpl(0) {} 114 115 //===--------------------------------------------------------------------===// 116 // Attribute Construction 117 //===--------------------------------------------------------------------===// 118 119 /// \brief Return a uniquified Attribute object. 120 static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0); 121 static Attribute get(LLVMContext &Context, StringRef Kind, 122 StringRef Val = StringRef()); 123 124 /// \brief Return a uniquified Attribute object that has the specific 125 /// alignment set. 126 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align); 127 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align); 128 129 //===--------------------------------------------------------------------===// 130 // Attribute Accessors 131 //===--------------------------------------------------------------------===// 132 133 /// \brief Return true if the attribute is an Attribute::AttrKind type. 134 bool isEnumAttribute() const; 135 136 /// \brief Return true if the attribute is an alignment attribute. 137 bool isAlignAttribute() const; 138 139 /// \brief Return true if the attribute is a string (target-dependent) 140 /// attribute. 141 bool isStringAttribute() const; 142 143 /// \brief Return true if the attribute is present. 144 bool hasAttribute(AttrKind Val) const; 145 146 /// \brief Return true if the target-dependent attribute is present. 147 bool hasAttribute(StringRef Val) const; 148 149 /// \brief Return the attribute's kind as an enum (Attribute::AttrKind). This 150 /// requires the attribute to be an enum or alignment attribute. 151 Attribute::AttrKind getKindAsEnum() const; 152 153 /// \brief Return the attribute's value as an integer. This requires that the 154 /// attribute be an alignment attribute. 155 uint64_t getValueAsInt() const; 156 157 /// \brief Return the attribute's kind as a string. This requires the 158 /// attribute to be a string attribute. 159 StringRef getKindAsString() const; 160 161 /// \brief Return the attribute's value as a string. This requires the 162 /// attribute to be a string attribute. 163 StringRef getValueAsString() const; 164 165 /// \brief Returns the alignment field of an attribute as a byte alignment 166 /// value. 167 unsigned getAlignment() const; 168 169 /// \brief Returns the stack alignment field of an attribute as a byte 170 /// alignment value. 171 unsigned getStackAlignment() const; 172 173 /// \brief The Attribute is converted to a string of equivalent mnemonic. This 174 /// is, presumably, for writing out the mnemonics for the assembly writer. 175 std::string getAsString(bool InAttrGrp = false) const; 176 177 /// \brief Equality and non-equality operators. 178 bool operator==(Attribute A) const { return pImpl == A.pImpl; } 179 bool operator!=(Attribute A) const { return pImpl != A.pImpl; } 180 181 /// \brief Less-than operator. Useful for sorting the attributes list. 182 bool operator<(Attribute A) const; 183 184 void Profile(FoldingSetNodeID &ID) const { 185 ID.AddPointer(pImpl); 186 } 187}; 188 189//===----------------------------------------------------------------------===// 190/// \class 191/// \brief This class holds the attributes for a function, its return value, and 192/// its parameters. You access the attributes for each of them via an index into 193/// the AttributeSet object. The function attributes are at index 194/// `AttributeSet::FunctionIndex', the return value is at index 195/// `AttributeSet::ReturnIndex', and the attributes for the parameters start at 196/// index `1'. 197class AttributeSet { 198public: 199 enum AttrIndex { 200 ReturnIndex = 0U, 201 FunctionIndex = ~0U 202 }; 203private: 204 friend class AttrBuilder; 205 friend class AttributeSetImpl; 206 template <typename Ty> friend struct DenseMapInfo; 207 208 /// \brief The attributes that we are managing. This can be null to represent 209 /// the empty attributes list. 210 AttributeSetImpl *pImpl; 211 212 /// \brief The attributes for the specified index are returned. 213 AttributeSetNode *getAttributes(unsigned Index) const; 214 215 /// \brief Create an AttributeSet with the specified parameters in it. 216 static AttributeSet get(LLVMContext &C, 217 ArrayRef<std::pair<unsigned, Attribute> > Attrs); 218 static AttributeSet get(LLVMContext &C, 219 ArrayRef<std::pair<unsigned, 220 AttributeSetNode*> > Attrs); 221 222 static AttributeSet getImpl(LLVMContext &C, 223 ArrayRef<std::pair<unsigned, 224 AttributeSetNode*> > Attrs); 225 226 227 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {} 228public: 229 AttributeSet() : pImpl(0) {} 230 231 //===--------------------------------------------------------------------===// 232 // AttributeSet Construction and Mutation 233 //===--------------------------------------------------------------------===// 234 235 /// \brief Return an AttributeSet with the specified parameters in it. 236 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs); 237 static AttributeSet get(LLVMContext &C, unsigned Index, 238 ArrayRef<Attribute::AttrKind> Kind); 239 static AttributeSet get(LLVMContext &C, unsigned Index, AttrBuilder &B); 240 241 /// \brief Add an attribute to the attribute set at the given index. Since 242 /// attribute sets are immutable, this returns a new set. 243 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 244 Attribute::AttrKind Attr) const; 245 246 /// \brief Add an attribute to the attribute set at the given index. Since 247 /// attribute sets are immutable, this returns a new set. 248 AttributeSet addAttribute(LLVMContext &C, unsigned Index, 249 StringRef Kind) const; 250 251 /// \brief Add attributes to the attribute set at the given index. Since 252 /// attribute sets are immutable, this returns a new set. 253 AttributeSet addAttributes(LLVMContext &C, unsigned Index, 254 AttributeSet Attrs) const; 255 256 /// \brief Remove the specified attribute at the specified index from this 257 /// attribute list. Since attribute lists are immutable, this returns the new 258 /// list. 259 AttributeSet removeAttribute(LLVMContext &C, unsigned Index, 260 Attribute::AttrKind Attr) const; 261 262 /// \brief Remove the specified attributes at the specified index from this 263 /// attribute list. Since attribute lists are immutable, this returns the new 264 /// list. 265 AttributeSet removeAttributes(LLVMContext &C, unsigned Index, 266 AttributeSet Attrs) const; 267 268 //===--------------------------------------------------------------------===// 269 // AttributeSet Accessors 270 //===--------------------------------------------------------------------===// 271 272 /// \brief Retrieve the LLVM context. 273 LLVMContext &getContext() const; 274 275 /// \brief The attributes for the specified index are returned. 276 AttributeSet getParamAttributes(unsigned Index) const; 277 278 /// \brief The attributes for the ret value are returned. 279 AttributeSet getRetAttributes() const; 280 281 /// \brief The function attributes are returned. 282 AttributeSet getFnAttributes() const; 283 284 /// \brief Return true if the attribute exists at the given index. 285 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const; 286 287 /// \brief Return true if the attribute exists at the given index. 288 bool hasAttribute(unsigned Index, StringRef Kind) const; 289 290 /// \brief Return true if attribute exists at the given index. 291 bool hasAttributes(unsigned Index) const; 292 293 /// \brief Return true if the specified attribute is set for at least one 294 /// parameter or for the return value. 295 bool hasAttrSomewhere(Attribute::AttrKind Attr) const; 296 297 /// \brief Return the attribute object that exists at the given index. 298 Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const; 299 300 /// \brief Return the attribute object that exists at the given index. 301 Attribute getAttribute(unsigned Index, StringRef Kind) const; 302 303 /// \brief Return the alignment for the specified function parameter. 304 unsigned getParamAlignment(unsigned Index) const; 305 306 /// \brief Get the stack alignment. 307 unsigned getStackAlignment(unsigned Index) const; 308 309 /// \brief Return the attributes at the index as a string. 310 std::string getAsString(unsigned Index, bool TargetIndependent = true, 311 bool InAttrGrp = false) const; 312 313 typedef ArrayRef<Attribute>::iterator iterator; 314 315 iterator begin(unsigned Slot) const; 316 iterator end(unsigned Slot) const; 317 318 /// operator==/!= - Provide equality predicates. 319 bool operator==(const AttributeSet &RHS) const { 320 return pImpl == RHS.pImpl; 321 } 322 bool operator!=(const AttributeSet &RHS) const { 323 return pImpl != RHS.pImpl; 324 } 325 326 //===--------------------------------------------------------------------===// 327 // AttributeSet Introspection 328 //===--------------------------------------------------------------------===// 329 330 // FIXME: Remove this. 331 uint64_t Raw(unsigned Index) const; 332 333 /// \brief Return a raw pointer that uniquely identifies this attribute list. 334 void *getRawPointer() const { 335 return pImpl; 336 } 337 338 /// \brief Return true if there are no attributes. 339 bool isEmpty() const { 340 return getNumSlots() == 0; 341 } 342 343 /// \brief Return the number of slots used in this attribute list. This is 344 /// the number of arguments that have an attribute set on them (including the 345 /// function itself). 346 unsigned getNumSlots() const; 347 348 /// \brief Return the index for the given slot. 349 unsigned getSlotIndex(unsigned Slot) const; 350 351 /// \brief Return the attributes at the given slot. 352 AttributeSet getSlotAttributes(unsigned Slot) const; 353 354 void dump() const; 355}; 356 357//===----------------------------------------------------------------------===// 358/// \class 359/// \brief Provide DenseMapInfo for AttributeSet. 360template<> struct DenseMapInfo<AttributeSet> { 361 static inline AttributeSet getEmptyKey() { 362 uintptr_t Val = static_cast<uintptr_t>(-1); 363 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 364 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 365 } 366 static inline AttributeSet getTombstoneKey() { 367 uintptr_t Val = static_cast<uintptr_t>(-2); 368 Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable; 369 return AttributeSet(reinterpret_cast<AttributeSetImpl*>(Val)); 370 } 371 static unsigned getHashValue(AttributeSet AS) { 372 return (unsigned((uintptr_t)AS.pImpl) >> 4) ^ 373 (unsigned((uintptr_t)AS.pImpl) >> 9); 374 } 375 static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; } 376}; 377 378//===----------------------------------------------------------------------===// 379/// \class 380/// \brief This class is used in conjunction with the Attribute::get method to 381/// create an Attribute object. The object itself is uniquified. The Builder's 382/// value, however, is not. So this can be used as a quick way to test for 383/// equality, presence of attributes, etc. 384class AttrBuilder { 385 std::bitset<Attribute::EndAttrKinds> Attrs; 386 std::map<std::string, std::string> TargetDepAttrs; 387 uint64_t Alignment; 388 uint64_t StackAlignment; 389public: 390 AttrBuilder() : Attrs(0), Alignment(0), StackAlignment(0) {} 391 explicit AttrBuilder(uint64_t Val) 392 : Attrs(0), Alignment(0), StackAlignment(0) { 393 addRawValue(Val); 394 } 395 AttrBuilder(const Attribute &A) : Attrs(0), Alignment(0), StackAlignment(0) { 396 addAttribute(A); 397 } 398 AttrBuilder(AttributeSet AS, unsigned Idx); 399 AttrBuilder(const AttrBuilder &B) 400 : Attrs(B.Attrs), 401 TargetDepAttrs(B.TargetDepAttrs.begin(), B.TargetDepAttrs.end()), 402 Alignment(B.Alignment), StackAlignment(B.StackAlignment) {} 403 404 void clear(); 405 406 /// \brief Add an attribute to the builder. 407 AttrBuilder &addAttribute(Attribute::AttrKind Val); 408 409 /// \brief Add the Attribute object to the builder. 410 AttrBuilder &addAttribute(Attribute A); 411 412 /// \brief Add the target-dependent attribute to the builder. 413 AttrBuilder &addAttribute(StringRef A, StringRef V = StringRef()); 414 415 /// \brief Remove an attribute from the builder. 416 AttrBuilder &removeAttribute(Attribute::AttrKind Val); 417 418 /// \brief Remove the attributes from the builder. 419 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index); 420 421 /// \brief Remove the target-dependent attribute to the builder. 422 AttrBuilder &removeAttribute(StringRef A); 423 424 /// \brief Add the attributes from the builder. 425 AttrBuilder &merge(const AttrBuilder &B); 426 427 /// \brief Return true if the builder has the specified attribute. 428 bool contains(Attribute::AttrKind A) const { 429 assert((unsigned)A < Attribute::EndAttrKinds && "Attribute out of range!"); 430 return Attrs[A]; 431 } 432 433 /// \brief Return true if the builder has the specified target-dependent 434 /// attribute. 435 bool contains(StringRef A) const; 436 437 /// \brief Return true if the builder has IR-level attributes. 438 bool hasAttributes() const; 439 440 /// \brief Return true if the builder has any attribute that's in the 441 /// specified attribute. 442 bool hasAttributes(AttributeSet A, uint64_t Index) const; 443 444 /// \brief Return true if the builder has an alignment attribute. 445 bool hasAlignmentAttr() const; 446 447 /// \brief Retrieve the alignment attribute, if it exists. 448 uint64_t getAlignment() const { return Alignment; } 449 450 /// \brief Retrieve the stack alignment attribute, if it exists. 451 uint64_t getStackAlignment() const { return StackAlignment; } 452 453 /// \brief This turns an int alignment (which must be a power of 2) into the 454 /// form used internally in Attribute. 455 AttrBuilder &addAlignmentAttr(unsigned Align); 456 457 /// \brief This turns an int stack alignment (which must be a power of 2) into 458 /// the form used internally in Attribute. 459 AttrBuilder &addStackAlignmentAttr(unsigned Align); 460 461 /// \brief Return true if the builder contains no target-independent 462 /// attributes. 463 bool empty() const { return Attrs.none(); } 464 465 // Iterators for target-dependent attributes. 466 typedef std::pair<std::string, std::string> td_type; 467 typedef std::map<std::string, std::string>::iterator td_iterator; 468 typedef std::map<std::string, std::string>::const_iterator td_const_iterator; 469 470 td_iterator td_begin() { return TargetDepAttrs.begin(); } 471 td_iterator td_end() { return TargetDepAttrs.end(); } 472 473 td_const_iterator td_begin() const { return TargetDepAttrs.begin(); } 474 td_const_iterator td_end() const { return TargetDepAttrs.end(); } 475 476 bool td_empty() const { return TargetDepAttrs.empty(); } 477 478 bool operator==(const AttrBuilder &B); 479 bool operator!=(const AttrBuilder &B) { 480 return !(*this == B); 481 } 482 483 // FIXME: Remove this in 4.0. 484 485 /// \brief Add the raw value to the internal representation. 486 AttrBuilder &addRawValue(uint64_t Val); 487}; 488 489namespace AttributeFuncs { 490 491/// \brief Which attributes cannot be applied to a type. 492AttributeSet typeIncompatible(Type *Ty, uint64_t Index); 493 494} // end AttributeFuncs namespace 495 496} // end llvm namespace 497 498#endif 499