Attributes.h revision eddab1550ee10cce3bb26a26e88529cb19451aa3
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: The `uwtable' attribute is about the ABI or the user mandating an 47 /// entry in the unwind table. The `nounwind' attribute is about an exception 48 /// passing by the 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) {} 108 109 static Attribute get(LLVMContext &Context, AttrBuilder &B); 110public: 111 Attribute() : pImpl(0) {} 112 113 //===--------------------------------------------------------------------===// 114 // Attribute Construction 115 //===--------------------------------------------------------------------===// 116 117 /// \brief Return a uniquified Attribute object. 118 static Attribute get(LLVMContext &Context, AttrKind Kind); 119 120 /// \brief Return a uniquified Attribute object that has the specific 121 /// alignment set. 122 static Attribute getWithAlignment(LLVMContext &Context, uint64_t Align); 123 static Attribute getWithStackAlignment(LLVMContext &Context, uint64_t Align); 124 125 //===--------------------------------------------------------------------===// 126 // Attribute Accessors 127 //===--------------------------------------------------------------------===// 128 129 /// \brief Return true if the attribute is present. 130 bool hasAttribute(AttrKind Val) const; 131 132 /// \brief Return true if attributes exist 133 bool hasAttributes() const; 134 135 /// \brief Return the kind of this attribute. 136 Constant *getAttributeKind() const; 137 138 /// \brief Return the value (if present) of the non-target-specific attribute. 139 ArrayRef<Constant*> getAttributeValues() const; 140 141 /// \brief Returns the alignment field of an attribute as a byte alignment 142 /// value. 143 unsigned getAlignment() const; 144 145 /// \brief Returns the stack alignment field of an attribute as a byte 146 /// alignment value. 147 unsigned getStackAlignment() const; 148 149 /// \brief The Attribute is converted to a string of equivalent mnemonic. This 150 /// is, presumably, for writing out the mnemonics for the assembly writer. 151 std::string getAsString() const; 152 153 /// \brief Equality and non-equality query methods. 154 bool operator==(AttrKind K) const; 155 bool operator!=(AttrKind K) const; 156 157 bool operator==(Attribute A) const { return pImpl == A.pImpl; } 158 bool operator!=(Attribute A) const { return pImpl != A.pImpl; } 159 160 /// \brief Less-than operator. Useful for sorting the attributes list. 161 bool operator<(Attribute A) const; 162 163 void Profile(FoldingSetNodeID &ID) const { 164 ID.AddPointer(pImpl); 165 } 166 167 // FIXME: Remove this. 168 uint64_t Raw() const; 169}; 170 171//===----------------------------------------------------------------------===// 172/// \class 173/// \brief This class manages the ref count for the opaque AttributeSetImpl 174/// object and provides accessors for it. 175class AttributeSet { 176public: 177 enum AttrIndex { 178 ReturnIndex = 0U, 179 FunctionIndex = ~0U 180 }; 181private: 182 friend class AttrBuilder; 183 friend class AttributeSetImpl; 184 185 /// \brief The attributes that we are managing. This can be null to represent 186 /// the empty attributes list. 187 AttributeSetImpl *pImpl; 188 189 /// \brief The attributes for the specified index are returned. 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 Remove the specified attribute at the specified index from this 234 /// attribute list. Since attribute lists are immutable, this returns the new 235 /// list. 236 AttributeSet removeAttribute(LLVMContext &C, unsigned Idx, 237 Attribute::AttrKind Attr) const; 238 239 /// \brief Remove the specified attributes at the specified index from this 240 /// attribute list. Since attribute lists are immutable, this returns the new 241 /// list. 242 AttributeSet removeAttributes(LLVMContext &C, unsigned Idx, 243 AttributeSet Attrs) const; 244 245 //===--------------------------------------------------------------------===// 246 // AttributeSet Accessors 247 //===--------------------------------------------------------------------===// 248 249 /// \brief The attributes for the specified index are returned. 250 AttributeSet getParamAttributes(unsigned Idx) const; 251 252 /// \brief The attributes for the ret value are returned. 253 AttributeSet getRetAttributes() const; 254 255 /// \brief The function attributes are returned. 256 AttributeSet getFnAttributes() const; 257 258 /// \brief Return true if the attribute exists at the given index. 259 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const; 260 261 /// \brief Return true if attribute exists at the given index. 262 bool hasAttributes(unsigned Index) const; 263 264 /// \brief Return true if the specified attribute is set for at least one 265 /// parameter or for the return value. 266 bool hasAttrSomewhere(Attribute::AttrKind Attr) const; 267 268 /// \brief Return the alignment for the specified function parameter. 269 unsigned getParamAlignment(unsigned Idx) const; 270 271 /// \brief Get the stack alignment. 272 unsigned getStackAlignment(unsigned Index) const; 273 274 /// \brief Return the attributes at the index as a string. 275 std::string getAsString(unsigned Index) const; 276 277 /// operator==/!= - Provide equality predicates. 278 bool operator==(const AttributeSet &RHS) const { 279 return pImpl == RHS.pImpl; 280 } 281 bool operator!=(const AttributeSet &RHS) const { 282 return pImpl != RHS.pImpl; 283 } 284 285 //===--------------------------------------------------------------------===// 286 // AttributeSet Introspection 287 //===--------------------------------------------------------------------===// 288 289 // FIXME: Remove this. 290 uint64_t Raw(unsigned Index) const; 291 292 /// \brief Return a raw pointer that uniquely identifies this attribute list. 293 void *getRawPointer() const { 294 return pImpl; 295 } 296 297 /// \brief Return true if there are no attributes. 298 bool isEmpty() const { 299 return getNumSlots() == 0; 300 } 301 302 /// \brief Return the number of slots used in this attribute list. This is 303 /// the number of arguments that have an attribute set on them (including the 304 /// function itself). 305 unsigned getNumSlots() const; 306 307 /// \brief Return the index for the given slot. 308 uint64_t getSlotIndex(unsigned Slot) const; 309 310 /// \brief Return the attributes at the given slot. 311 AttributeSet getSlotAttributes(unsigned Slot) const; 312 313 void dump() const; 314}; 315 316//===----------------------------------------------------------------------===// 317/// \class 318/// \brief Provide DenseMapInfo for Attribute::AttrKinds. This is used by 319/// AttrBuilder. 320template<> struct DenseMapInfo<Attribute::AttrKind> { 321 static inline Attribute::AttrKind getEmptyKey() { 322 return Attribute::AttrKindEmptyKey; 323 } 324 static inline Attribute::AttrKind getTombstoneKey() { 325 return Attribute::AttrKindTombstoneKey; 326 } 327 static unsigned getHashValue(const Attribute::AttrKind &Val) { 328 return Val * 37U; 329 } 330 static bool isEqual(const Attribute::AttrKind &LHS, 331 const Attribute::AttrKind &RHS) { 332 return LHS == RHS; 333 } 334}; 335 336//===----------------------------------------------------------------------===// 337/// \class 338/// \brief This class is used in conjunction with the Attribute::get method to 339/// create an Attribute object. The object itself is uniquified. The Builder's 340/// value, however, is not. So this can be used as a quick way to test for 341/// equality, presence of attributes, etc. 342class AttrBuilder { 343 DenseSet<Attribute::AttrKind> Attrs; 344 uint64_t Alignment; 345 uint64_t StackAlignment; 346public: 347 AttrBuilder() : Alignment(0), StackAlignment(0) {} 348 explicit AttrBuilder(uint64_t B) : Alignment(0), StackAlignment(0) { 349 addRawValue(B); 350 } 351 AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) { 352 addAttributes(A); 353 } 354 AttrBuilder(AttributeSet AS, unsigned Idx); 355 356 void clear(); 357 358 /// \brief Add an attribute to the builder. 359 AttrBuilder &addAttribute(Attribute::AttrKind Val); 360 361 /// \brief Remove an attribute from the builder. 362 AttrBuilder &removeAttribute(Attribute::AttrKind Val); 363 364 /// \brief Add the attributes to the builder. 365 AttrBuilder &addAttributes(Attribute A); 366 367 /// \brief Remove the attributes from the builder. 368 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index); 369 370 /// \brief Return true if the builder has the specified attribute. 371 bool contains(Attribute::AttrKind A) const; 372 373 /// \brief Return true if the builder has IR-level attributes. 374 bool hasAttributes() const; 375 376 /// \brief Return true if the builder has any attribute that's in the 377 /// specified attribute. 378 bool hasAttributes(AttributeSet A, uint64_t Index) const; 379 380 /// \brief Return true if the builder has an alignment attribute. 381 bool hasAlignmentAttr() const; 382 383 /// \brief Retrieve the alignment attribute, if it exists. 384 uint64_t getAlignment() const { return Alignment; } 385 386 /// \brief Retrieve the stack alignment attribute, if it exists. 387 uint64_t getStackAlignment() const { return StackAlignment; } 388 389 /// \brief This turns an int alignment (which must be a power of 2) into the 390 /// form used internally in Attribute. 391 AttrBuilder &addAlignmentAttr(unsigned Align); 392 393 /// \brief This turns an int stack alignment (which must be a power of 2) into 394 /// the form used internally in Attribute. 395 AttrBuilder &addStackAlignmentAttr(unsigned Align); 396 397 typedef DenseSet<Attribute::AttrKind>::iterator iterator; 398 typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator; 399 400 iterator begin() { return Attrs.begin(); } 401 iterator end() { return Attrs.end(); } 402 403 const_iterator begin() const { return Attrs.begin(); } 404 const_iterator end() const { return Attrs.end(); } 405 406 /// \brief Remove attributes that are used on functions only. 407 void removeFunctionOnlyAttrs() { 408 removeAttribute(Attribute::NoReturn) 409 .removeAttribute(Attribute::NoUnwind) 410 .removeAttribute(Attribute::ReadNone) 411 .removeAttribute(Attribute::ReadOnly) 412 .removeAttribute(Attribute::NoInline) 413 .removeAttribute(Attribute::AlwaysInline) 414 .removeAttribute(Attribute::OptimizeForSize) 415 .removeAttribute(Attribute::StackProtect) 416 .removeAttribute(Attribute::StackProtectReq) 417 .removeAttribute(Attribute::StackProtectStrong) 418 .removeAttribute(Attribute::NoRedZone) 419 .removeAttribute(Attribute::NoImplicitFloat) 420 .removeAttribute(Attribute::Naked) 421 .removeAttribute(Attribute::InlineHint) 422 .removeAttribute(Attribute::StackAlignment) 423 .removeAttribute(Attribute::UWTable) 424 .removeAttribute(Attribute::NonLazyBind) 425 .removeAttribute(Attribute::ReturnsTwice) 426 .removeAttribute(Attribute::AddressSafety) 427 .removeAttribute(Attribute::MinSize) 428 .removeAttribute(Attribute::NoDuplicate); 429 } 430 431 bool operator==(const AttrBuilder &B); 432 bool operator!=(const AttrBuilder &B) { 433 return !(*this == B); 434 } 435 436 // FIXME: Remove these. 437 438 /// \brief Add the raw value to the internal representation. 439 /// 440 /// N.B. This should be used ONLY for decoding LLVM bitcode! 441 AttrBuilder &addRawValue(uint64_t Val); 442 443 uint64_t Raw() const; 444}; 445 446namespace AttributeFuncs { 447 448/// \brief Which attributes cannot be applied to a type. 449AttributeSet typeIncompatible(Type *Ty, uint64_t Index); 450 451/// \brief This returns an integer containing an encoding of all the LLVM 452/// attributes found in the given attribute bitset. Any change to this encoding 453/// is a breaking change to bitcode compatibility. 454uint64_t encodeLLVMAttributesForBitcode(AttributeSet Attrs, unsigned Index); 455 456/// \brief This fills an AttrBuilder object with the LLVM attributes that have 457/// been decoded from the given integer. This function must stay in sync with 458/// 'encodeLLVMAttributesForBitcode'. 459/// N.B. This should be used only by the bitcode reader! 460void decodeLLVMAttributesForBitcode(LLVMContext &C, AttrBuilder &B, 461 uint64_t EncodedAttrs); 462 463} // end AttributeFuncs namespace 464 465} // end llvm namespace 466 467#endif 468