Attributes.h revision ea59f896a672c2e1ef9f02277bce60257aa60989
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 <map> 24#include <string> 25 26namespace llvm { 27 28class AttrBuilder; 29class AttributeImpl; 30class AttributeSetImpl; 31class AttributeSetNode; 32class Constant; 33class LLVMContext; 34class Type; 35 36//===----------------------------------------------------------------------===// 37/// \class 38/// \brief Functions, function parameters, and return types can have attributes 39/// to indicate how they should be treated by optimizations and code 40/// generation. This class represents one of those attributes. It's light-weight 41/// and should be passed around by-value. 42class Attribute { 43public: 44 /// This enumeration lists the attributes that can be associated with 45 /// parameters, function results, or the function itself. 46 /// 47 /// Note: The `uwtable' attribute is about the ABI or the user mandating an 48 /// entry in the unwind table. The `nounwind' attribute is about an exception 49 /// passing by the function. 50 /// 51 /// In a theoretical system that uses tables for profiling and SjLj for 52 /// exceptions, they would be fully independent. In a normal system that uses 53 /// tables for both, the semantics are: 54 /// 55 /// nil = Needs an entry because an exception might pass by. 56 /// nounwind = No need for an entry 57 /// uwtable = Needs an entry because the ABI says so and because 58 /// an exception might pass by. 59 /// uwtable + nounwind = Needs an entry because the ABI says so. 60 61 enum AttrKind { 62 // IR-Level Attributes 63 None, ///< No attributes have been set 64 AddressSafety, ///< Address safety checking is on. 65 Alignment, ///< Alignment of parameter (5 bits) 66 ///< stored as log2 of alignment with +1 bias 67 ///< 0 means unaligned (different from align(1)) 68 AlwaysInline, ///< inline=always 69 ByVal, ///< Pass structure by value 70 InlineHint, ///< Source said inlining was desirable 71 InReg, ///< Force argument to be passed in register 72 MinSize, ///< Function must be optimized for size first 73 Naked, ///< Naked function 74 Nest, ///< Nested function static chain 75 NoAlias, ///< Considered to not alias after call 76 NoCapture, ///< Function creates no aliases of pointer 77 NoDuplicate, ///< Call cannot be duplicated 78 NoImplicitFloat, ///< Disable implicit floating point insts 79 NoInline, ///< inline=never 80 NonLazyBind, ///< Function is called early and/or 81 ///< often, so lazy binding isn't worthwhile 82 NoRedZone, ///< Disable redzone 83 NoReturn, ///< Mark the function as not returning 84 NoUnwind, ///< Function doesn't unwind stack 85 OptimizeForSize, ///< opt_size 86 ReadNone, ///< Function does not access memory 87 ReadOnly, ///< Function only reads from memory 88 ReturnsTwice, ///< Function can return twice 89 SExt, ///< Sign extended before/after call 90 StackAlignment, ///< Alignment of stack for function (3 bits) 91 ///< stored as log2 of alignment with +1 bias 0 92 ///< means unaligned (different from 93 ///< alignstack=(1)) 94 StackProtect, ///< Stack protection. 95 StackProtectReq, ///< Stack protection required. 96 StackProtectStrong, ///< Strong Stack protection. 97 StructRet, ///< Hidden pointer to structure to return 98 UWTable, ///< Function must be in a unwind table 99 ZExt, ///< Zero extended before/after call 100 101 EndAttrKinds, ///< Sentinal value useful for loops 102 103 AttrKindEmptyKey, ///< Empty key value for DenseMapInfo 104 AttrKindTombstoneKey ///< Tombstone key value for DenseMapInfo 105 }; 106private: 107 AttributeImpl *pImpl; 108 Attribute(AttributeImpl *A) : pImpl(A) {} 109public: 110 Attribute() : pImpl(0) {} 111 112 //===--------------------------------------------------------------------===// 113 // Attribute Construction 114 //===--------------------------------------------------------------------===// 115 116 /// \brief Return a uniquified Attribute object. 117 static Attribute get(LLVMContext &Context, AttrKind Kind, Constant *Val = 0); 118 static Attribute get(LLVMContext &Context, Constant *Kind, Constant *Val = 0); 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 the kind of this attribute: enum or string. 133 Constant *getAttributeKind() const; 134 135 /// \brief Return the values (if present) of the attribute. This may be a 136 /// ConstantVector to represent a list of values associated with the 137 /// attribute. 138 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}; 166 167//===----------------------------------------------------------------------===// 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 typedef ArrayRef<Attribute>::iterator iterator; 274 275 iterator begin(unsigned Idx) const; 276 iterator end(unsigned Idx) const; 277 278 /// operator==/!= - Provide equality predicates. 279 bool operator==(const AttributeSet &RHS) const { 280 return pImpl == RHS.pImpl; 281 } 282 bool operator!=(const AttributeSet &RHS) const { 283 return pImpl != RHS.pImpl; 284 } 285 286 //===--------------------------------------------------------------------===// 287 // AttributeSet Introspection 288 //===--------------------------------------------------------------------===// 289 290 // FIXME: Remove this. 291 uint64_t Raw(unsigned Index) const; 292 293 /// \brief Return a raw pointer that uniquely identifies this attribute list. 294 void *getRawPointer() const { 295 return pImpl; 296 } 297 298 /// \brief Return true if there are no attributes. 299 bool isEmpty() const { 300 return getNumSlots() == 0; 301 } 302 303 /// \brief Return the number of slots used in this attribute list. This is 304 /// the number of arguments that have an attribute set on them (including the 305 /// function itself). 306 unsigned getNumSlots() const; 307 308 /// \brief Return the index for the given slot. 309 uint64_t getSlotIndex(unsigned Slot) const; 310 311 /// \brief Return the attributes at the given slot. 312 AttributeSet getSlotAttributes(unsigned Slot) const; 313 314 void dump() const; 315}; 316 317//===----------------------------------------------------------------------===// 318/// \class 319/// \brief Provide DenseMapInfo for Attribute::AttrKinds. This is used by 320/// AttrBuilder. 321template<> struct DenseMapInfo<Attribute::AttrKind> { 322 static inline Attribute::AttrKind getEmptyKey() { 323 return Attribute::AttrKindEmptyKey; 324 } 325 static inline Attribute::AttrKind getTombstoneKey() { 326 return Attribute::AttrKindTombstoneKey; 327 } 328 static unsigned getHashValue(const Attribute::AttrKind &Val) { 329 return Val * 37U; 330 } 331 static bool isEqual(const Attribute::AttrKind &LHS, 332 const Attribute::AttrKind &RHS) { 333 return LHS == RHS; 334 } 335}; 336 337//===----------------------------------------------------------------------===// 338/// \class 339/// \brief This class is used in conjunction with the Attribute::get method to 340/// create an Attribute object. The object itself is uniquified. The Builder's 341/// value, however, is not. So this can be used as a quick way to test for 342/// equality, presence of attributes, etc. 343class AttrBuilder { 344 DenseSet<Attribute::AttrKind> Attrs; 345 std::map<std::string, std::string> TargetDepAttrs; 346 uint64_t Alignment; 347 uint64_t StackAlignment; 348public: 349 AttrBuilder() : Alignment(0), StackAlignment(0) {} 350 explicit AttrBuilder(uint64_t Val) : Alignment(0), StackAlignment(0) { 351 addRawValue(Val); 352 } 353 AttrBuilder(const Attribute &A) : Alignment(0), StackAlignment(0) { 354 addAttribute(A); 355 } 356 AttrBuilder(AttributeSet AS, unsigned Idx); 357 358 void clear(); 359 360 /// \brief Add an attribute to the builder. 361 AttrBuilder &addAttribute(Attribute::AttrKind Val); 362 363 /// \brief Add the Attribute object to the builder. 364 AttrBuilder &addAttribute(Attribute A); 365 366 /// \brief Add the target-dependent attribute to the builder. 367 AttrBuilder &addAttribute(StringRef A, StringRef V); 368 369 /// \brief Remove an attribute from the builder. 370 AttrBuilder &removeAttribute(Attribute::AttrKind Val); 371 372 /// \brief Remove the attributes from the builder. 373 AttrBuilder &removeAttributes(AttributeSet A, uint64_t Index); 374 375 /// \brief Remove the target-dependent attribute to the builder. 376 AttrBuilder &removeAttribute(StringRef A); 377 378 /// \brief Return true if the builder has the specified attribute. 379 bool contains(Attribute::AttrKind A) const; 380 381 /// \brief Return true if the builder has IR-level attributes. 382 bool hasAttributes() const; 383 384 /// \brief Return true if the builder has any attribute that's in the 385 /// specified attribute. 386 bool hasAttributes(AttributeSet A, uint64_t Index) const; 387 388 /// \brief Return true if the builder has an alignment attribute. 389 bool hasAlignmentAttr() const; 390 391 /// \brief Retrieve the alignment attribute, if it exists. 392 uint64_t getAlignment() const { return Alignment; } 393 394 /// \brief Retrieve the stack alignment attribute, if it exists. 395 uint64_t getStackAlignment() const { return StackAlignment; } 396 397 /// \brief This turns an int alignment (which must be a power of 2) into the 398 /// form used internally in Attribute. 399 AttrBuilder &addAlignmentAttr(unsigned Align); 400 401 /// \brief This turns an int stack alignment (which must be a power of 2) into 402 /// the form used internally in Attribute. 403 AttrBuilder &addStackAlignmentAttr(unsigned Align); 404 405 typedef DenseSet<Attribute::AttrKind>::iterator iterator; 406 typedef DenseSet<Attribute::AttrKind>::const_iterator const_iterator; 407 408 iterator begin() { return Attrs.begin(); } 409 iterator end() { return Attrs.end(); } 410 411 const_iterator begin() const { return Attrs.begin(); } 412 const_iterator end() const { return Attrs.end(); } 413 414 /// \brief Remove attributes that are used on functions only. 415 void removeFunctionOnlyAttrs() { 416 removeAttribute(Attribute::NoReturn) 417 .removeAttribute(Attribute::NoUnwind) 418 .removeAttribute(Attribute::ReadNone) 419 .removeAttribute(Attribute::ReadOnly) 420 .removeAttribute(Attribute::NoInline) 421 .removeAttribute(Attribute::AlwaysInline) 422 .removeAttribute(Attribute::OptimizeForSize) 423 .removeAttribute(Attribute::StackProtect) 424 .removeAttribute(Attribute::StackProtectReq) 425 .removeAttribute(Attribute::StackProtectStrong) 426 .removeAttribute(Attribute::NoRedZone) 427 .removeAttribute(Attribute::NoImplicitFloat) 428 .removeAttribute(Attribute::Naked) 429 .removeAttribute(Attribute::InlineHint) 430 .removeAttribute(Attribute::StackAlignment) 431 .removeAttribute(Attribute::UWTable) 432 .removeAttribute(Attribute::NonLazyBind) 433 .removeAttribute(Attribute::ReturnsTwice) 434 .removeAttribute(Attribute::AddressSafety) 435 .removeAttribute(Attribute::MinSize) 436 .removeAttribute(Attribute::NoDuplicate); 437 } 438 439 bool operator==(const AttrBuilder &B); 440 bool operator!=(const AttrBuilder &B) { 441 return !(*this == B); 442 } 443 444 // FIXME: Remove this in 4.0. 445 446 /// \brief Add the raw value to the internal representation. 447 AttrBuilder &addRawValue(uint64_t Val); 448}; 449 450namespace AttributeFuncs { 451 452/// \brief Which attributes cannot be applied to a type. 453AttributeSet typeIncompatible(Type *Ty, uint64_t Index); 454 455} // end AttributeFuncs namespace 456 457} // end llvm namespace 458 459#endif 460