Attributes.h revision 6dc3781d44e56f0addf28b06232a50f3f9e6b1af
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/DenseSet.h" 21#include "llvm/ADT/FoldingSet.h" 22#include <cassert> 23#include <string> 24 25namespace llvm { 26 27class AttrBuilder; 28class AttributeImpl; 29class AttributeSetImpl; 30class AttributeSetNode; 31class Constant; 32class LLVMContext; 33class Type; 34 35//===----------------------------------------------------------------------===// 36/// \class 37/// \brief Functions, function parameters, and return types can have attributes 38/// to indicate how they should be treated by optimizations and code 39/// generation. This class represents one of those attributes. It's light-weight 40/// and should be passed around by-value. 41class Attribute { 42public: 43 /// This enumeration lists the attributes that can be associated with 44 /// parameters, function results or the function itself. 45 /// 46 /// Note: uwtable is about the ABI or the user mandating an entry in the 47 /// unwind table. The nounwind attribute is about an exception passing by the 48 /// function. 49 /// 50 /// In a theoretical system that uses tables for profiling and sjlj for 51 /// exceptions, they would be fully independent. In a normal system that uses 52 /// tables for both, the semantics are: 53 /// 54 /// nil = Needs an entry because an exception might pass by. 55 /// nounwind = No need for an entry 56 /// uwtable = Needs an entry because the ABI says so and because 57 /// an exception might pass by. 58 /// uwtable + nounwind = Needs an entry because the ABI says so. 59 60 enum AttrKind { 61 // IR-Level Attributes 62 None, ///< No attributes have been set 63 AddressSafety, ///< Address safety checking is on. 64 Alignment, ///< Alignment of parameter (5 bits) 65 ///< stored as log2 of alignment with +1 bias 66 ///< 0 means unaligned (different from align(1)) 67 AlwaysInline, ///< inline=always 68 ByVal, ///< Pass structure by value 69 InlineHint, ///< Source said inlining was desirable 70 InReg, ///< Force argument to be passed in register 71 MinSize, ///< Function must be optimized for size first 72 Naked, ///< Naked function 73 Nest, ///< Nested function static chain 74 NoAlias, ///< Considered to not alias after call 75 NoCapture, ///< Function creates no aliases of pointer 76 NoDuplicate, ///< Call cannot be duplicated 77 NoImplicitFloat, ///< Disable implicit floating point insts 78 NoInline, ///< inline=never 79 NonLazyBind, ///< Function is called early and/or 80 ///< often, so lazy binding isn't worthwhile 81 NoRedZone, ///< Disable redzone 82 NoReturn, ///< Mark the function as not returning 83 NoUnwind, ///< Function doesn't unwind stack 84 OptimizeForSize, ///< opt_size 85 ReadNone, ///< Function does not access memory 86 ReadOnly, ///< Function only reads from memory 87 ReturnsTwice, ///< Function can return twice 88 SExt, ///< Sign extended before/after call 89 StackAlignment, ///< Alignment of stack for function (3 bits) 90 ///< stored as log2 of alignment with +1 bias 0 91 ///< means unaligned (different from 92 ///< alignstack=(1)) 93 StackProtect, ///< Stack protection. 94 StackProtectReq, ///< Stack protection required. 95 StackProtectStrong, ///< Strong Stack protection. 96 StructRet, ///< Hidden pointer to structure to return 97 UWTable, ///< Function must be in a unwind table 98 ZExt, ///< Zero extended before/after call 99 100 EndAttrKinds, ///< Sentinal value useful for loops 101 102 AttrKindEmptyKey, ///< Empty key value for DenseMapInfo 103 AttrKindTombstoneKey ///< Tombstone key value for DenseMapInfo 104 }; 105private: 106 AttributeImpl *pImpl; 107 Attribute(AttributeImpl *A) : pImpl(A) {} 108public: 109 Attribute() : pImpl(0) {} 110 111 //===--------------------------------------------------------------------===// 112 // Attribute Construction 113 //===--------------------------------------------------------------------===// 114 115 /// \brief Return a uniquified Attribute object. 116 static Attribute get(LLVMContext &Context, AttrKind Kind); 117 static Attribute get(LLVMContext &Context, AttrBuilder &B); 118 119 /// \brief Return a uniquified Attribute object that has the specific 120 /// alignment set. 121 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align); 122 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align); 123 124 //===--------------------------------------------------------------------===// 125 // Attribute Accessors 126 //===--------------------------------------------------------------------===// 127 128 /// \brief Return true if the attribute is present. 129 bool hasAttribute(AttrKind Val) const; 130 131 /// \brief Return true if attributes exist 132 bool hasAttributes() const; 133 134 /// \brief Return the kind of this attribute. 135 Constant *getAttributeKind() const; 136 137 /// \brief Return the value (if present) of the non-target-specific attribute. 138 ArrayRef<Constant*> getAttributeValues() const; 139 140 /// \brief Returns the alignment field of an attribute as a byte alignment 141 /// value. 142 unsigned getAlignment() const; 143 144 /// \brief Returns the stack alignment field of an attribute as a byte 145 /// alignment value. 146 unsigned getStackAlignment() const; 147 148 /// \brief The Attribute is converted to a string of equivalent mnemonic. This 149 /// is, presumably, for writing out the mnemonics for the assembly writer. 150 std::string getAsString() const; 151 152 /// \brief Equality and non-equality query methods. 153 bool operator==(AttrKind K) const; 154 bool operator!=(AttrKind K) const; 155 156 bool operator==(Attribute A) const { return pImpl == A.pImpl; } 157 bool operator!=(Attribute A) const { return pImpl != A.pImpl; } 158 159 /// \brief Less-than operator. Useful for sorting the attributes list. 160 bool operator<(Attribute A) const; 161 162 void Profile(FoldingSetNodeID &ID) const { 163 ID.AddPointer(pImpl); 164 } 165 166 // FIXME: Remove this. 167 uint64_t Raw() const; 168}; 169 170//===----------------------------------------------------------------------===// 171/// \class 172/// \brief This class manages the ref count for the opaque AttributeSetImpl 173/// object and provides accessors for it. 174class AttributeSet { 175public: 176 enum AttrIndex { 177 ReturnIndex = 0U, 178 FunctionIndex = ~0U 179 }; 180private: 181 friend class AttrBuilder; 182 friend class AttributeSetImpl; 183 184 /// \brief The attributes that we are managing. This can be null to represent 185 /// the empty attributes list. 186 AttributeSetImpl *pImpl; 187 188 /// \brief The attributes for the specified index are returned. Attributes 189 /// for the result are denoted with Idx = 0. 190 AttributeSetNode *getAttributes(unsigned Idx) const; 191 192 /// \brief Create an AttributeSet with the specified parameters in it. 193 static AttributeSet get(LLVMContext &C, 194 ArrayRef<std::pair<unsigned, Attribute> > Attrs); 195 static AttributeSet get(LLVMContext &C, 196 ArrayRef<std::pair<unsigned, 197 AttributeSetNode*> > Attrs); 198 199 static AttributeSet getImpl(LLVMContext &C, 200 ArrayRef<std::pair<unsigned, 201 AttributeSetNode*> > Attrs); 202 203 204 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {} 205public: 206 AttributeSet() : pImpl(0) {} 207 AttributeSet(const AttributeSet &P) : pImpl(P.pImpl) {} 208 const AttributeSet &operator=(const AttributeSet &RHS) { 209 pImpl = RHS.pImpl; 210 return *this; 211 } 212 213 //===--------------------------------------------------------------------===// 214 // AttributeSet Construction and Mutation 215 //===--------------------------------------------------------------------===// 216 217 /// \brief Return an AttributeSet with the specified parameters in it. 218 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs); 219 static AttributeSet get(LLVMContext &C, unsigned Idx, 220 ArrayRef<Attribute::AttrKind> Kind); 221 static AttributeSet get(LLVMContext &C, unsigned Idx, AttrBuilder &B); 222 223 /// \brief Add an attribute to the attribute set at the given index. Since 224 /// attribute sets are immutable, this returns a new set. 225 AttributeSet addAttribute(LLVMContext &C, unsigned Idx, 226 Attribute::AttrKind Attr) const; 227 228 /// \brief Add attributes to the attribute set at the given index. Since 229 /// attribute sets are immutable, this returns a new set. 230 AttributeSet addAttributes(LLVMContext &C, unsigned Idx, 231 AttributeSet Attrs) const; 232 233 /// \brief Add return attributes to this attribute set. Since attribute sets 234 /// are immutable, this returns a new set. 235 AttributeSet addRetAttributes(LLVMContext &C, AttributeSet Attrs) const { 236 return addAttributes(C, ReturnIndex, Attrs); 237 } 238 239 /// \brief Add function attributes to this attribute set. Since attribute sets 240 /// are immutable, this returns a new set. 241 AttributeSet addFnAttributes(LLVMContext &C, AttributeSet Attrs) const { 242 return addAttributes(C, FunctionIndex, Attrs); 243 } 244 245 /// \brief Remove the specified attribute at the specified index from this 246 /// attribute list. Since attribute lists are immutable, this returns the new 247 /// list. 248 AttributeSet removeAttribute(LLVMContext &C, unsigned Idx, 249 Attribute::AttrKind Attr) const; 250 251 /// \brief Remove the specified attributes at the specified index from this 252 /// attribute list. Since attribute lists are immutable, this returns the new 253 /// list. 254 AttributeSet removeAttributes(LLVMContext &C, unsigned Idx, 255 AttributeSet Attrs) const; 256 257 //===--------------------------------------------------------------------===// 258 // AttributeSet Accessors 259 //===--------------------------------------------------------------------===// 260 261 /// \brief The attributes for the specified index are returned. 262 AttributeSet getParamAttributes(unsigned Idx) const; 263 264 /// \brief The attributes for the ret value are returned. 265 AttributeSet getRetAttributes() const; 266 267 /// \brief The function attributes are returned. 268 AttributeSet getFnAttributes() const; 269 270 /// \brief Return true if the attribute exists at the given index. 271 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const; 272 273 /// \brief Return true if attribute exists at the given index. 274 bool hasAttributes(unsigned Index) const; 275 276 /// \brief Return true if the specified attribute is set for at least one 277 /// parameter or for the return value. 278 bool hasAttrSomewhere(Attribute::AttrKind Attr) const; 279 280 /// \brief Return the alignment for the specified function parameter. 281 unsigned getParamAlignment(unsigned Idx) const; 282 283 /// \brief Get the stack alignment. 284 unsigned getStackAlignment(unsigned Index) const; 285 286 /// \brief Return the attributes at the index as a string. 287 std::string getAsString(unsigned Index) const; 288 289 /// operator==/!= - Provide equality predicates. 290 bool operator==(const AttributeSet &RHS) const { 291 return pImpl == RHS.pImpl; 292 } 293 bool operator!=(const AttributeSet &RHS) const { 294 return pImpl != RHS.pImpl; 295 } 296 297 //===--------------------------------------------------------------------===// 298 // AttributeSet Introspection 299 //===--------------------------------------------------------------------===// 300 301 // FIXME: Remove this. 302 uint64_t Raw(unsigned Index) const; 303 304 /// \brief Return a raw pointer that uniquely identifies this attribute list. 305 void *getRawPointer() const { 306 return pImpl; 307 } 308 309 /// \brief Return true if there are no attributes. 310 bool isEmpty() const { 311 return pImpl == 0; 312 } 313 314 /// \brief Return the number of slots used in this attribute list. This is 315 /// the number of arguments that have an attribute set on them (including the 316 /// function itself). 317 unsigned getNumSlots() const; 318 319 /// \brief Return the index for the given slot. 320 uint64_t getSlotIndex(unsigned Slot) const; 321 322 /// \brief Return the attributes at the given slot. 323 AttributeSet getSlotAttributes(unsigned Slot) const; 324 325 void dump() const; 326}; 327 328//===----------------------------------------------------------------------===// 329/// \class 330/// \brief Provide DenseMapInfo for Attribute::AttrKinds. This is used by 331/// AttrBuilder. 332template<> struct DenseMapInfo<Attribute::AttrKind> { 333 static inline Attribute::AttrKind getEmptyKey() { 334 return Attribute::AttrKindEmptyKey; 335 } 336 static inline Attribute::AttrKind getTombstoneKey() { 337 return Attribute::AttrKindTombstoneKey; 338 } 339 static unsigned getHashValue(const Attribute::AttrKind &Val) { 340 return Val * 37U; 341 } 342 static bool isEqual(const Attribute::AttrKind &LHS, 343 const Attribute::AttrKind &RHS) { 344 return LHS == RHS; 345 } 346}; 347 348//===----------------------------------------------------------------------===// 349/// \class 350/// \brief This class is used in conjunction with the Attribute::get method to 351/// create an Attribute object. The object itself is uniquified. The Builder's 352/// value, however, is not. So this can be used as a quick way to test for 353/// equality, presence of attributes, etc. 354class AttrBuilder { 355 DenseSet<Attribute::AttrKind> Attrs; 356 uint64_t Alignment; 357 uint64_t StackAlignment; 358public: 359 AttrBuilder() : Alignment(0), StackAlignment(0) {} 360 explicit AttrBuilder(uint64_t B) : Alignment(0), StackAlignment(0) { 361 addRawValue(B); 362 } 363 AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) { 364 addAttributes(A); 365 } 366 AttrBuilder(AttributeSet AS, unsigned Idx); 367 368 void clear(); 369 370 /// \brief Add an attribute to the builder. 371 AttrBuilder &addAttribute(Attribute::AttrKind Val); 372 373 /// \brief Remove an attribute from the builder. 374 AttrBuilder &removeAttribute(Attribute::AttrKind Val); 375 376 /// \brief Add the attributes to the builder. 377 AttrBuilder &addAttributes(Attribute A); 378 379 /// \brief Remove the attributes from the builder. 380 AttrBuilder &removeAttributes(Attribute A); 381 382 /// \brief Add the attributes to the builder. 383 AttrBuilder &addAttributes(AttributeSet A); 384 385 /// \brief Return true if the builder has the specified attribute. 386 bool contains(Attribute::AttrKind A) const; 387 388 /// \brief Return true if the builder has IR-level attributes. 389 bool hasAttributes() const; 390 391 /// \brief Return true if the builder has any attribute that's in the 392 /// specified attribute. 393 bool hasAttributes(const Attribute &A) const; 394 395 /// \brief Return true if the builder has an alignment attribute. 396 bool hasAlignmentAttr() const; 397 398 /// \brief Retrieve the alignment attribute, if it exists. 399 uint64_t getAlignment() const { return Alignment; } 400 401 /// \brief Retrieve the stack alignment attribute, if it exists. 402 uint64_t getStackAlignment() const { return StackAlignment; } 403 404 /// \brief This turns an int alignment (which must be a power of 2) into the 405 /// form used internally in Attribute. 406 AttrBuilder &addAlignmentAttr(unsigned Align); 407 408 /// \brief This turns an int stack alignment (which must be a power of 2) into 409 /// the form used internally in Attribute. 410 AttrBuilder &addStackAlignmentAttr(unsigned Align); 411 412 typedef DenseSet<Attribute::AttrKind>::iterator iterator; 413 typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator; 414 415 iterator begin() { return Attrs.begin(); } 416 iterator end() { return Attrs.end(); } 417 418 const_iterator begin() const { return Attrs.begin(); } 419 const_iterator end() const { return Attrs.end(); } 420 421 /// \brief Remove attributes that are used on functions only. 422 void removeFunctionOnlyAttrs() { 423 removeAttribute(Attribute::NoReturn) 424 .removeAttribute(Attribute::NoUnwind) 425 .removeAttribute(Attribute::ReadNone) 426 .removeAttribute(Attribute::ReadOnly) 427 .removeAttribute(Attribute::NoInline) 428 .removeAttribute(Attribute::AlwaysInline) 429 .removeAttribute(Attribute::OptimizeForSize) 430 .removeAttribute(Attribute::StackProtect) 431 .removeAttribute(Attribute::StackProtectReq) 432 .removeAttribute(Attribute::StackProtectStrong) 433 .removeAttribute(Attribute::NoRedZone) 434 .removeAttribute(Attribute::NoImplicitFloat) 435 .removeAttribute(Attribute::Naked) 436 .removeAttribute(Attribute::InlineHint) 437 .removeAttribute(Attribute::StackAlignment) 438 .removeAttribute(Attribute::UWTable) 439 .removeAttribute(Attribute::NonLazyBind) 440 .removeAttribute(Attribute::ReturnsTwice) 441 .removeAttribute(Attribute::AddressSafety) 442 .removeAttribute(Attribute::MinSize) 443 .removeAttribute(Attribute::NoDuplicate); 444 } 445 446 bool operator==(const AttrBuilder &B); 447 bool operator!=(const AttrBuilder &B) { 448 return !(*this == B); 449 } 450 451 // FIXME: Remove these. 452 453 /// \brief Add the raw value to the internal representation. 454 /// 455 /// N.B. This should be used ONLY for decoding LLVM bitcode! 456 AttrBuilder &addRawValue(uint64_t Val); 457 458 uint64_t Raw() const; 459}; 460 461namespace AttributeFuncs { 462 463/// \brief Which attributes cannot be applied to a type. 464Attribute typeIncompatible(Type *Ty); 465 466/// \brief This returns an integer containing an encoding of all the LLVM 467/// attributes found in the given attribute bitset. Any change to this encoding 468/// is a breaking change to bitcode compatibility. 469uint64_t encodeLLVMAttributesForBitcode(AttributeSet Attrs, unsigned Index); 470 471/// \brief This fills an AttrBuilder object with the LLVM attributes that have 472/// been decoded from the given integer. This function must stay in sync with 473/// 'encodeLLVMAttributesForBitcode'. 474/// N.B. This should be used only by the bitcode reader! 475void decodeLLVMAttributesForBitcode(LLVMContext &C, AttrBuilder &B, 476 uint64_t EncodedAttrs); 477 478} // end AttributeFuncs namespace 479 480} // end llvm namespace 481 482#endif 483