Attributes.h revision 169d5270751597aed4095ead00401a3374906147
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) {} 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, Constant *Val = 0); 117 static Attribute get(LLVMContext &Context, Constant *Kind, Constant *Val = 0); 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 the kind of this attribute. 132 Constant *getAttributeKind() const; 133 134 /// \brief Return the value (if present) of the non-target-specific attribute. 135 ArrayRef<Constant*> getAttributeValues() const; 136 137 /// \brief Returns the alignment field of an attribute as a byte alignment 138 /// value. 139 unsigned getAlignment() const; 140 141 /// \brief Returns the stack alignment field of an attribute as a byte 142 /// alignment value. 143 unsigned getStackAlignment() const; 144 145 /// \brief The Attribute is converted to a string of equivalent mnemonic. This 146 /// is, presumably, for writing out the mnemonics for the assembly writer. 147 std::string getAsString() const; 148 149 /// \brief Equality and non-equality query methods. 150 bool operator==(AttrKind K) const; 151 bool operator!=(AttrKind K) const; 152 153 bool operator==(Attribute A) const { return pImpl == A.pImpl; } 154 bool operator!=(Attribute A) const { return pImpl != A.pImpl; } 155 156 /// \brief Less-than operator. Useful for sorting the attributes list. 157 bool operator<(Attribute A) const; 158 159 void Profile(FoldingSetNodeID &ID) const { 160 ID.AddPointer(pImpl); 161 } 162 163 // FIXME: Remove this. 164 uint64_t Raw() const; 165}; 166 167//===----------------------------------------------------------------------===// 168/// \class 169/// \brief This class manages the ref count for the opaque AttributeSetImpl 170/// object and provides accessors for it. 171class AttributeSet { 172public: 173 enum AttrIndex { 174 ReturnIndex = 0U, 175 FunctionIndex = ~0U 176 }; 177private: 178 friend class AttrBuilder; 179 friend class AttributeSetImpl; 180 181 /// \brief The attributes that we are managing. This can be null to represent 182 /// the empty attributes list. 183 AttributeSetImpl *pImpl; 184 185 /// \brief The attributes for the specified index are returned. 186 AttributeSetNode *getAttributes(unsigned Idx) const; 187 188 /// \brief Create an AttributeSet with the specified parameters in it. 189 static AttributeSet get(LLVMContext &C, 190 ArrayRef<std::pair<unsigned, Attribute> > Attrs); 191 static AttributeSet get(LLVMContext &C, 192 ArrayRef<std::pair<unsigned, 193 AttributeSetNode*> > Attrs); 194 195 static AttributeSet getImpl(LLVMContext &C, 196 ArrayRef<std::pair<unsigned, 197 AttributeSetNode*> > Attrs); 198 199 200 explicit AttributeSet(AttributeSetImpl *LI) : pImpl(LI) {} 201public: 202 AttributeSet() : pImpl(0) {} 203 AttributeSet(const AttributeSet &P) : pImpl(P.pImpl) {} 204 const AttributeSet &operator=(const AttributeSet &RHS) { 205 pImpl = RHS.pImpl; 206 return *this; 207 } 208 209 //===--------------------------------------------------------------------===// 210 // AttributeSet Construction and Mutation 211 //===--------------------------------------------------------------------===// 212 213 /// \brief Return an AttributeSet with the specified parameters in it. 214 static AttributeSet get(LLVMContext &C, ArrayRef<AttributeSet> Attrs); 215 static AttributeSet get(LLVMContext &C, unsigned Idx, 216 ArrayRef<Attribute::AttrKind> Kind); 217 static AttributeSet get(LLVMContext &C, unsigned Idx, AttrBuilder &B); 218 219 /// \brief Add an attribute to the attribute set at the given index. Since 220 /// attribute sets are immutable, this returns a new set. 221 AttributeSet addAttribute(LLVMContext &C, unsigned Idx, 222 Attribute::AttrKind Attr) const; 223 224 /// \brief Add attributes to the attribute set at the given index. Since 225 /// attribute sets are immutable, this returns a new set. 226 AttributeSet addAttributes(LLVMContext &C, unsigned Idx, 227 AttributeSet Attrs) const; 228 229 /// \brief Remove the specified attribute at the specified index from this 230 /// attribute list. Since attribute lists are immutable, this returns the new 231 /// list. 232 AttributeSet removeAttribute(LLVMContext &C, unsigned Idx, 233 Attribute::AttrKind Attr) const; 234 235 /// \brief Remove the specified attributes at the specified index from this 236 /// attribute list. Since attribute lists are immutable, this returns the new 237 /// list. 238 AttributeSet removeAttributes(LLVMContext &C, unsigned Idx, 239 AttributeSet Attrs) const; 240 241 //===--------------------------------------------------------------------===// 242 // AttributeSet Accessors 243 //===--------------------------------------------------------------------===// 244 245 /// \brief The attributes for the specified index are returned. 246 AttributeSet getParamAttributes(unsigned Idx) const; 247 248 /// \brief The attributes for the ret value are returned. 249 AttributeSet getRetAttributes() const; 250 251 /// \brief The function attributes are returned. 252 AttributeSet getFnAttributes() const; 253 254 /// \brief Return true if the attribute exists at the given index. 255 bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const; 256 257 /// \brief Return true if attribute exists at the given index. 258 bool hasAttributes(unsigned Index) const; 259 260 /// \brief Return true if the specified attribute is set for at least one 261 /// parameter or for the return value. 262 bool hasAttrSomewhere(Attribute::AttrKind Attr) const; 263 264 /// \brief Return the alignment for the specified function parameter. 265 unsigned getParamAlignment(unsigned Idx) const; 266 267 /// \brief Get the stack alignment. 268 unsigned getStackAlignment(unsigned Index) const; 269 270 /// \brief Return the attributes at the index as a string. 271 std::string getAsString(unsigned Index) const; 272 273 /// operator==/!= - Provide equality predicates. 274 bool operator==(const AttributeSet &RHS) const { 275 return pImpl == RHS.pImpl; 276 } 277 bool operator!=(const AttributeSet &RHS) const { 278 return pImpl != RHS.pImpl; 279 } 280 281 //===--------------------------------------------------------------------===// 282 // AttributeSet Introspection 283 //===--------------------------------------------------------------------===// 284 285 // FIXME: Remove this. 286 uint64_t Raw(unsigned Index) const; 287 288 /// \brief Return a raw pointer that uniquely identifies this attribute list. 289 void *getRawPointer() const { 290 return pImpl; 291 } 292 293 /// \brief Return true if there are no attributes. 294 bool isEmpty() const { 295 return getNumSlots() == 0; 296 } 297 298 /// \brief Return the number of slots used in this attribute list. This is 299 /// the number of arguments that have an attribute set on them (including the 300 /// function itself). 301 unsigned getNumSlots() const; 302 303 /// \brief Return the index for the given slot. 304 uint64_t getSlotIndex(unsigned Slot) const; 305 306 /// \brief Return the attributes at the given slot. 307 AttributeSet getSlotAttributes(unsigned Slot) const; 308 309 void dump() const; 310}; 311 312//===----------------------------------------------------------------------===// 313/// \class 314/// \brief Provide DenseMapInfo for Attribute::AttrKinds. This is used by 315/// AttrBuilder. 316template<> struct DenseMapInfo<Attribute::AttrKind> { 317 static inline Attribute::AttrKind getEmptyKey() { 318 return Attribute::AttrKindEmptyKey; 319 } 320 static inline Attribute::AttrKind getTombstoneKey() { 321 return Attribute::AttrKindTombstoneKey; 322 } 323 static unsigned getHashValue(const Attribute::AttrKind &Val) { 324 return Val * 37U; 325 } 326 static bool isEqual(const Attribute::AttrKind &LHS, 327 const Attribute::AttrKind &RHS) { 328 return LHS == RHS; 329 } 330}; 331 332//===----------------------------------------------------------------------===// 333/// \class 334/// \brief This class is used in conjunction with the Attribute::get method to 335/// create an Attribute object. The object itself is uniquified. The Builder's 336/// value, however, is not. So this can be used as a quick way to test for 337/// equality, presence of attributes, etc. 338class AttrBuilder { 339 DenseSet<Attribute::AttrKind> Attrs; 340 uint64_t Alignment; 341 uint64_t StackAlignment; 342public: 343 AttrBuilder() : Alignment(0), StackAlignment(0) {} 344 explicit AttrBuilder(uint64_t B) : Alignment(0), StackAlignment(0) { 345 addRawValue(B); 346 } 347 AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) { 348 addAttributes(A); 349 } 350 AttrBuilder(AttributeSet AS, unsigned Idx); 351 352 void clear(); 353 354 /// \brief Add an attribute to the builder. 355 AttrBuilder &addAttribute(Attribute::AttrKind Val); 356 357 /// \brief Remove an attribute from the builder. 358 AttrBuilder &removeAttribute(Attribute::AttrKind Val); 359 360 /// \brief Add the attributes to the builder. 361 AttrBuilder &addAttributes(Attribute A); 362 363 /// \brief Remove the attributes from the builder. 364 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index); 365 366 /// \brief Return true if the builder has the specified attribute. 367 bool contains(Attribute::AttrKind A) const; 368 369 /// \brief Return true if the builder has IR-level attributes. 370 bool hasAttributes() const; 371 372 /// \brief Return true if the builder has any attribute that's in the 373 /// specified attribute. 374 bool hasAttributes(AttributeSet A, uint64_t Index) const; 375 376 /// \brief Return true if the builder has an alignment attribute. 377 bool hasAlignmentAttr() const; 378 379 /// \brief Retrieve the alignment attribute, if it exists. 380 uint64_t getAlignment() const { return Alignment; } 381 382 /// \brief Retrieve the stack alignment attribute, if it exists. 383 uint64_t getStackAlignment() const { return StackAlignment; } 384 385 /// \brief This turns an int alignment (which must be a power of 2) into the 386 /// form used internally in Attribute. 387 AttrBuilder &addAlignmentAttr(unsigned Align); 388 389 /// \brief This turns an int stack alignment (which must be a power of 2) into 390 /// the form used internally in Attribute. 391 AttrBuilder &addStackAlignmentAttr(unsigned Align); 392 393 typedef DenseSet<Attribute::AttrKind>::iterator iterator; 394 typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator; 395 396 iterator begin() { return Attrs.begin(); } 397 iterator end() { return Attrs.end(); } 398 399 const_iterator begin() const { return Attrs.begin(); } 400 const_iterator end() const { return Attrs.end(); } 401 402 /// \brief Remove attributes that are used on functions only. 403 void removeFunctionOnlyAttrs() { 404 removeAttribute(Attribute::NoReturn) 405 .removeAttribute(Attribute::NoUnwind) 406 .removeAttribute(Attribute::ReadNone) 407 .removeAttribute(Attribute::ReadOnly) 408 .removeAttribute(Attribute::NoInline) 409 .removeAttribute(Attribute::AlwaysInline) 410 .removeAttribute(Attribute::OptimizeForSize) 411 .removeAttribute(Attribute::StackProtect) 412 .removeAttribute(Attribute::StackProtectReq) 413 .removeAttribute(Attribute::StackProtectStrong) 414 .removeAttribute(Attribute::NoRedZone) 415 .removeAttribute(Attribute::NoImplicitFloat) 416 .removeAttribute(Attribute::Naked) 417 .removeAttribute(Attribute::InlineHint) 418 .removeAttribute(Attribute::StackAlignment) 419 .removeAttribute(Attribute::UWTable) 420 .removeAttribute(Attribute::NonLazyBind) 421 .removeAttribute(Attribute::ReturnsTwice) 422 .removeAttribute(Attribute::AddressSafety) 423 .removeAttribute(Attribute::MinSize) 424 .removeAttribute(Attribute::NoDuplicate); 425 } 426 427 bool operator==(const AttrBuilder &B); 428 bool operator!=(const AttrBuilder &B) { 429 return !(*this == B); 430 } 431 432 // FIXME: Remove these. 433 434 /// \brief Add the raw value to the internal representation. 435 /// 436 /// N.B. This should be used ONLY for decoding LLVM bitcode! 437 AttrBuilder &addRawValue(uint64_t Val); 438 439 uint64_t Raw() const; 440}; 441 442namespace AttributeFuncs { 443 444/// \brief Which attributes cannot be applied to a type. 445AttributeSet typeIncompatible(Type *Ty, uint64_t Index); 446 447/// \brief This returns an integer containing an encoding of all the LLVM 448/// attributes found in the given attribute bitset. Any change to this encoding 449/// is a breaking change to bitcode compatibility. 450uint64_t encodeLLVMAttributesForBitcode(AttributeSet Attrs, unsigned Index); 451 452/// \brief This fills an AttrBuilder object with the LLVM attributes that have 453/// been decoded from the given integer. This function must stay in sync with 454/// 'encodeLLVMAttributesForBitcode'. 455/// N.B. This should be used only by the bitcode reader! 456void decodeLLVMAttributesForBitcode(LLVMContext &C, AttrBuilder &B, 457 uint64_t EncodedAttrs); 458 459} // end AttributeFuncs namespace 460 461} // end llvm namespace 462 463#endif 464