include/llvm/IR/Attributes.h

   1 //===- llvm/Attributes.h - Container for Attributes -------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 /// \file
  10 /// This file contains the simple types necessary to represent the
  11 /// attributes associated with functions and their calls.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef LLVM_IR_ATTRIBUTES_H
  16 #define LLVM_IR_ATTRIBUTES_H
  17
  18 #include "llvm-c/Types.h"
  19 #include "llvm/ADT/ArrayRef.h"
  20 #include "llvm/ADT/FoldingSet.h"
  21 #include "llvm/ADT/Optional.h"
  22 #include "llvm/ADT/StringRef.h"
  23 #include "llvm/ADT/iterator_range.h"
  24 #include "llvm/Config/llvm-config.h"
  25 #include "llvm/Support/Alignment.h"
  26 #include "llvm/Support/PointerLikeTypeTraits.h"
  27 #include <bitset>
  28 #include <cassert>
  29 #include <cstdint>
  30 #include <map>
  31 #include <string>
  32 #include <utility>
  33
  34 namespace llvm {
  35
  36 class AttrBuilder;
  37 class AttributeImpl;
  38 class AttributeListImpl;
  39 class AttributeSetNode;
  40 template<typename T> struct DenseMapInfo;
  41 class Function;
  42 class LLVMContext;
  43 class Type;
  44
  45 //===----------------------------------------------------------------------===//
  46 /// \class
  47 /// Functions, function parameters, and return types can have attributes
  48 /// to indicate how they should be treated by optimizations and code
  49 /// generation. This class represents one of those attributes. It's light-weight
  50 /// and should be passed around by-value.
  51 class Attribute {
  52 public:
  53   /// This enumeration lists the attributes that can be associated with
  54   /// parameters, function results, or the function itself.
  55   ///
  56   /// Note: The `uwtable' attribute is about the ABI or the user mandating an
  57   /// entry in the unwind table. The `nounwind' attribute is about an exception
  58   /// passing by the function.
  59   ///
  60   /// In a theoretical system that uses tables for profiling and SjLj for
  61   /// exceptions, they would be fully independent. In a normal system that uses
  62   /// tables for both, the semantics are:
  63   ///
  64   /// nil                = Needs an entry because an exception might pass by.
  65   /// nounwind           = No need for an entry
  66   /// uwtable            = Needs an entry because the ABI says so and because
  67   ///                      an exception might pass by.
  68   /// uwtable + nounwind = Needs an entry because the ABI says so.
  69
  70   enum AttrKind {
  71     // IR-Level Attributes
  72     None,                  ///< No attributes have been set
  73     #define GET_ATTR_ENUM
  74     #include "llvm/IR/Attributes.inc"
  75     EndAttrKinds           ///< Sentinal value useful for loops
  76   };
  77
  78 private:
  79   AttributeImpl *pImpl = nullptr;
  80
  81   Attribute(AttributeImpl *A) : pImpl(A) {}
  82
  83 public:
  84   Attribute() = default;
  85
  86   //===--------------------------------------------------------------------===//
  87   // Attribute Construction
  88   //===--------------------------------------------------------------------===//
  89
  90   /// Return a uniquified Attribute object.
  91   static Attribute get(LLVMContext &Context, AttrKind Kind, uint64_t Val = 0);
  92   static Attribute get(LLVMContext &Context, StringRef Kind,
  93                        StringRef Val = StringRef());
  94   static Attribute get(LLVMContext &Context, AttrKind Kind, Type *Ty);
  95
  96   /// Return a uniquified Attribute object that has the specific
  97   /// alignment set.
  98   static Attribute getWithAlignment(LLVMContext &Context, Align Alignment);
  99   static Attribute getWithStackAlignment(LLVMContext &Context, Align Alignment);
 100   static Attribute getWithDereferenceableBytes(LLVMContext &Context,
 101                                               uint64_t Bytes);
 102   static Attribute getWithDereferenceableOrNullBytes(LLVMContext &Context,
 103                                                      uint64_t Bytes);
 104   static Attribute getWithAllocSizeArgs(LLVMContext &Context,
 105                                         unsigned ElemSizeArg,
 106                                         const Optional<unsigned> &NumElemsArg);
 107   static Attribute getWithByValType(LLVMContext &Context, Type *Ty);
 108
 109   //===--------------------------------------------------------------------===//
 110   // Attribute Accessors
 111   //===--------------------------------------------------------------------===//
 112
 113   /// Return true if the attribute is an Attribute::AttrKind type.
 114   bool isEnumAttribute() const;
 115
 116   /// Return true if the attribute is an integer attribute.
 117   bool isIntAttribute() const;
 118
 119   /// Return true if the attribute is a string (target-dependent)
 120   /// attribute.
 121   bool isStringAttribute() const;
 122
 123   /// Return true if the attribute is a type attribute.
 124   bool isTypeAttribute() const;
 125
 126   /// Return true if the attribute is present.
 127   bool hasAttribute(AttrKind Val) const;
 128
 129   /// Return true if the target-dependent attribute is present.
 130   bool hasAttribute(StringRef Val) const;
 131
 132   /// Return the attribute's kind as an enum (Attribute::AttrKind). This
 133   /// requires the attribute to be an enum or integer attribute.
 134   Attribute::AttrKind getKindAsEnum() const;
 135
 136   /// Return the attribute's value as an integer. This requires that the
 137   /// attribute be an integer attribute.
 138   uint64_t getValueAsInt() const;
 139
 140   /// Return the attribute's kind as a string. This requires the
 141   /// attribute to be a string attribute.
 142   StringRef getKindAsString() const;
 143
 144   /// Return the attribute's value as a string. This requires the
 145   /// attribute to be a string attribute.
 146   StringRef getValueAsString() const;
 147
 148   /// Return the attribute's value as a Type. This requires the attribute to be
 149   /// a type attribute.
 150   Type *getValueAsType() const;
 151
 152   /// Returns the alignment field of an attribute as a byte alignment
 153   /// value.
 154   MaybeAlign getAlignment() const;
 155
 156   /// Returns the stack alignment field of an attribute as a byte
 157   /// alignment value.
 158   MaybeAlign getStackAlignment() const;
 159
 160   /// Returns the number of dereferenceable bytes from the
 161   /// dereferenceable attribute.
 162   uint64_t getDereferenceableBytes() const;
 163
 164   /// Returns the number of dereferenceable_or_null bytes from the
 165   /// dereferenceable_or_null attribute.
 166   uint64_t getDereferenceableOrNullBytes() const;
 167
 168   /// Returns the argument numbers for the allocsize attribute (or pair(0, 0)
 169   /// if not known).
 170   std::pair<unsigned, Optional<unsigned>> getAllocSizeArgs() const;
 171
 172   /// The Attribute is converted to a string of equivalent mnemonic. This
 173   /// is, presumably, for writing out the mnemonics for the assembly writer.
 174   std::string getAsString(bool InAttrGrp = false) const;
 175
 176   /// Equality and non-equality operators.
 177   bool operator==(Attribute A) const { return pImpl == A.pImpl; }
 178   bool operator!=(Attribute A) const { return pImpl != A.pImpl; }
 179
 180   /// Less-than operator. Useful for sorting the attributes list.
 181   bool operator<(Attribute A) const;
 182
 183   void Profile(FoldingSetNodeID &ID) const {
 184     ID.AddPointer(pImpl);
 185   }
 186
 187   /// Return a raw pointer that uniquely identifies this attribute.
 188   void *getRawPointer() const {
 189     return pImpl;
 190   }
 191
 192   /// Get an attribute from a raw pointer created by getRawPointer.
 193   static Attribute fromRawPointer(void *RawPtr) {
 194     return Attribute(reinterpret_cast<AttributeImpl*>(RawPtr));
 195   }
 196 };
 197
 198 // Specialized opaque value conversions.
 199 inline LLVMAttributeRef wrap(Attribute Attr) {
 200   return reinterpret_cast<LLVMAttributeRef>(Attr.getRawPointer());
 201 }
 202
 203 // Specialized opaque value conversions.
 204 inline Attribute unwrap(LLVMAttributeRef Attr) {
 205   return Attribute::fromRawPointer(Attr);
 206 }
 207
 208 //===----------------------------------------------------------------------===//
 209 /// \class
 210 /// This class holds the attributes for a particular argument, parameter,
 211 /// function, or return value. It is an immutable value type that is cheap to
 212 /// copy. Adding and removing enum attributes is intended to be fast, but adding
 213 /// and removing string or integer attributes involves a FoldingSet lookup.
 214 class AttributeSet {
 215   friend AttributeListImpl;
 216   template <typename Ty> friend struct DenseMapInfo;
 217
 218   // TODO: Extract AvailableAttrs from AttributeSetNode and store them here.
 219   // This will allow an efficient implementation of addAttribute and
 220   // removeAttribute for enum attrs.
 221
 222   /// Private implementation pointer.
 223   AttributeSetNode *SetNode = nullptr;
 224
 225 private:
 226   explicit AttributeSet(AttributeSetNode *ASN) : SetNode(ASN) {}
 227
 228 public:
 229   /// AttributeSet is a trivially copyable value type.
 230   AttributeSet() = default;
 231   AttributeSet(const AttributeSet &) = default;
 232   ~AttributeSet() = default;
 233
 234   static AttributeSet get(LLVMContext &C, const AttrBuilder &B);
 235   static AttributeSet get(LLVMContext &C, ArrayRef<Attribute> Attrs);
 236
 237   bool operator==(const AttributeSet &O) const { return SetNode == O.SetNode; }
 238   bool operator!=(const AttributeSet &O) const { return !(*this == O); }
 239
 240   /// Add an argument attribute. Returns a new set because attribute sets are
 241   /// immutable.
 242   LLVM_NODISCARD AttributeSet addAttribute(LLVMContext &C,
 243                                            Attribute::AttrKind Kind) const;
 244
 245   /// Add a target-dependent attribute. Returns a new set because attribute sets
 246   /// are immutable.
 247   LLVM_NODISCARD AttributeSet addAttribute(LLVMContext &C, StringRef Kind,
 248                                            StringRef Value = StringRef()) const;
 249
 250   /// Add attributes to the attribute set. Returns a new set because attribute
 251   /// sets are immutable.
 252   LLVM_NODISCARD AttributeSet addAttributes(LLVMContext &C,
 253                                             AttributeSet AS) const;
 254
 255   /// Remove the specified attribute from this set. Returns a new set because
 256   /// attribute sets are immutable.
 257   LLVM_NODISCARD AttributeSet removeAttribute(LLVMContext &C,
 258                                               Attribute::AttrKind Kind) const;
 259
 260   /// Remove the specified attribute from this set. Returns a new set because
 261   /// attribute sets are immutable.
 262   LLVM_NODISCARD AttributeSet removeAttribute(LLVMContext &C,
 263                                               StringRef Kind) const;
 264
 265   /// Remove the specified attributes from this set. Returns a new set because
 266   /// attribute sets are immutable.
 267   LLVM_NODISCARD AttributeSet
 268   removeAttributes(LLVMContext &C, const AttrBuilder &AttrsToRemove) const;
 269
 270   /// Return the number of attributes in this set.
 271   unsigned getNumAttributes() const;
 272
 273   /// Return true if attributes exists in this set.
 274   bool hasAttributes() const { return SetNode != nullptr; }
 275
 276   /// Return true if the attribute exists in this set.
 277   bool hasAttribute(Attribute::AttrKind Kind) const;
 278
 279   /// Return true if the attribute exists in this set.
 280   bool hasAttribute(StringRef Kind) const;
 281
 282   /// Return the attribute object.
 283   Attribute getAttribute(Attribute::AttrKind Kind) const;
 284
 285   /// Return the target-dependent attribute object.
 286   Attribute getAttribute(StringRef Kind) const;
 287
 288   MaybeAlign getAlignment() const;
 289   MaybeAlign getStackAlignment() const;
 290   uint64_t getDereferenceableBytes() const;
 291   uint64_t getDereferenceableOrNullBytes() const;
 292   Type *getByValType() const;
 293   std::pair<unsigned, Optional<unsigned>> getAllocSizeArgs() const;
 294   std::string getAsString(bool InAttrGrp = false) const;
 295
 296   using iterator = const Attribute *;
 297
 298   iterator begin() const;
 299   iterator end() const;
 300 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 301   void dump() const;
 302 #endif
 303 };
 304
 305 //===----------------------------------------------------------------------===//
 306 /// \class
 307 /// Provide DenseMapInfo for AttributeSet.
 308 template <> struct DenseMapInfo<AttributeSet> {
 309   static AttributeSet getEmptyKey() {
 310     auto Val = static_cast<uintptr_t>(-1);
 311     Val <<= PointerLikeTypeTraits<void *>::NumLowBitsAvailable;
 312     return AttributeSet(reinterpret_cast<AttributeSetNode *>(Val));
 313   }
 314
 315   static AttributeSet getTombstoneKey() {
 316     auto Val = static_cast<uintptr_t>(-2);
 317     Val <<= PointerLikeTypeTraits<void *>::NumLowBitsAvailable;
 318     return AttributeSet(reinterpret_cast<AttributeSetNode *>(Val));
 319   }
 320
 321   static unsigned getHashValue(AttributeSet AS) {
 322     return (unsigned((uintptr_t)AS.SetNode) >> 4) ^
 323            (unsigned((uintptr_t)AS.SetNode) >> 9);
 324   }
 325
 326   static bool isEqual(AttributeSet LHS, AttributeSet RHS) { return LHS == RHS; }
 327 };
 328
 329 //===----------------------------------------------------------------------===//
 330 /// \class
 331 /// This class holds the attributes for a function, its return value, and
 332 /// its parameters. You access the attributes for each of them via an index into
 333 /// the AttributeList object. The function attributes are at index
 334 /// `AttributeList::FunctionIndex', the return value is at index
 335 /// `AttributeList::ReturnIndex', and the attributes for the parameters start at
 336 /// index `AttributeList::FirstArgIndex'.
 337 class AttributeList {
 338 public:
 339   enum AttrIndex : unsigned {
 340     ReturnIndex = 0U,
 341     FunctionIndex = ~0U,
 342     FirstArgIndex = 1,
 343   };
 344
 345 private:
 346   friend class AttrBuilder;
 347   friend class AttributeListImpl;
 348   friend class AttributeSet;
 349   friend class AttributeSetNode;
 350   template <typename Ty> friend struct DenseMapInfo;
 351
 352   /// The attributes that we are managing. This can be null to represent
 353   /// the empty attributes list.
 354   AttributeListImpl *pImpl = nullptr;
 355
 356 public:
 357   /// Create an AttributeList with the specified parameters in it.
 358   static AttributeList get(LLVMContext &C,
 359                            ArrayRef<std::pair<unsigned, Attribute>> Attrs);
 360   static AttributeList get(LLVMContext &C,
 361                            ArrayRef<std::pair<unsigned, AttributeSet>> Attrs);
 362
 363   /// Create an AttributeList from attribute sets for a function, its
 364   /// return value, and all of its arguments.
 365   static AttributeList get(LLVMContext &C, AttributeSet FnAttrs,
 366                            AttributeSet RetAttrs,
 367                            ArrayRef<AttributeSet> ArgAttrs);
 368
 369 private:
 370   explicit AttributeList(AttributeListImpl *LI) : pImpl(LI) {}
 371
 372   static AttributeList getImpl(LLVMContext &C, ArrayRef<AttributeSet> AttrSets);
 373
 374 public:
 375   AttributeList() = default;
 376
 377   //===--------------------------------------------------------------------===//
 378   // AttributeList Construction and Mutation
 379   //===--------------------------------------------------------------------===//
 380
 381   /// Return an AttributeList with the specified parameters in it.
 382   static AttributeList get(LLVMContext &C, ArrayRef<AttributeList> Attrs);
 383   static AttributeList get(LLVMContext &C, unsigned Index,
 384                            ArrayRef<Attribute::AttrKind> Kinds);
 385   static AttributeList get(LLVMContext &C, unsigned Index,
 386                            ArrayRef<StringRef> Kind);
 387   static AttributeList get(LLVMContext &C, unsigned Index,
 388                            const AttrBuilder &B);
 389
 390   /// Add an attribute to the attribute set at the given index.
 391   /// Returns a new list because attribute lists are immutable.
 392   LLVM_NODISCARD AttributeList addAttribute(LLVMContext &C, unsigned Index,
 393                                             Attribute::AttrKind Kind) const;
 394
 395   /// Add an attribute to the attribute set at the given index.
 396   /// Returns a new list because attribute lists are immutable.
 397   LLVM_NODISCARD AttributeList
 398   addAttribute(LLVMContext &C, unsigned Index, StringRef Kind,
 399                StringRef Value = StringRef()) const;
 400
 401   /// Add an attribute to the attribute set at the given index.
 402   /// Returns a new list because attribute lists are immutable.
 403   LLVM_NODISCARD AttributeList addAttribute(LLVMContext &C, unsigned Index,
 404                                             Attribute A) const;
 405
 406   /// Add attributes to the attribute set at the given index.
 407   /// Returns a new list because attribute lists are immutable.
 408   LLVM_NODISCARD AttributeList addAttributes(LLVMContext &C, unsigned Index,
 409                                              const AttrBuilder &B) const;
 410
 411   /// Add an argument attribute to the list. Returns a new list because
 412   /// attribute lists are immutable.
 413   LLVM_NODISCARD AttributeList addParamAttribute(
 414       LLVMContext &C, unsigned ArgNo, Attribute::AttrKind Kind) const {
 415     return addAttribute(C, ArgNo + FirstArgIndex, Kind);
 416   }
 417
 418   /// Add an argument attribute to the list. Returns a new list because
 419   /// attribute lists are immutable.
 420   LLVM_NODISCARD AttributeList
 421   addParamAttribute(LLVMContext &C, unsigned ArgNo, StringRef Kind,
 422                     StringRef Value = StringRef()) const {
 423     return addAttribute(C, ArgNo + FirstArgIndex, Kind, Value);
 424   }
 425
 426   /// Add an attribute to the attribute list at the given arg indices. Returns a
 427   /// new list because attribute lists are immutable.
 428   LLVM_NODISCARD AttributeList addParamAttribute(LLVMContext &C,
 429                                                  ArrayRef<unsigned> ArgNos,
 430                                                  Attribute A) const;
 431
 432   /// Add an argument attribute to the list. Returns a new list because
 433   /// attribute lists are immutable.
 434   LLVM_NODISCARD AttributeList addParamAttributes(LLVMContext &C,
 435                                                   unsigned ArgNo,
 436                                                   const AttrBuilder &B) const {
 437     return addAttributes(C, ArgNo + FirstArgIndex, B);
 438   }
 439
 440   /// Remove the specified attribute at the specified index from this
 441   /// attribute list. Returns a new list because attribute lists are immutable.
 442   LLVM_NODISCARD AttributeList removeAttribute(LLVMContext &C, unsigned Index,
 443                                                Attribute::AttrKind Kind) const;
 444
 445   /// Remove the specified attribute at the specified index from this
 446   /// attribute list. Returns a new list because attribute lists are immutable.
 447   LLVM_NODISCARD AttributeList removeAttribute(LLVMContext &C, unsigned Index,
 448                                                StringRef Kind) const;
 449
 450   /// Remove the specified attributes at the specified index from this
 451   /// attribute list. Returns a new list because attribute lists are immutable.
 452   LLVM_NODISCARD AttributeList removeAttributes(
 453       LLVMContext &C, unsigned Index, const AttrBuilder &AttrsToRemove) const;
 454
 455   /// Remove all attributes at the specified index from this
 456   /// attribute list. Returns a new list because attribute lists are immutable.
 457   LLVM_NODISCARD AttributeList removeAttributes(LLVMContext &C,
 458                                                 unsigned Index) const;
 459
 460   /// Remove the specified attribute at the specified arg index from this
 461   /// attribute list. Returns a new list because attribute lists are immutable.
 462   LLVM_NODISCARD AttributeList removeParamAttribute(
 463       LLVMContext &C, unsigned ArgNo, Attribute::AttrKind Kind) const {
 464     return removeAttribute(C, ArgNo + FirstArgIndex, Kind);
 465   }
 466
 467   /// Remove the specified attribute at the specified arg index from this
 468   /// attribute list. Returns a new list because attribute lists are immutable.
 469   LLVM_NODISCARD AttributeList removeParamAttribute(LLVMContext &C,
 470                                                     unsigned ArgNo,
 471                                                     StringRef Kind) const {
 472     return removeAttribute(C, ArgNo + FirstArgIndex, Kind);
 473   }
 474
 475   /// Remove the specified attribute at the specified arg index from this
 476   /// attribute list. Returns a new list because attribute lists are immutable.
 477   LLVM_NODISCARD AttributeList removeParamAttributes(
 478       LLVMContext &C, unsigned ArgNo, const AttrBuilder &AttrsToRemove) const {
 479     return removeAttributes(C, ArgNo + FirstArgIndex, AttrsToRemove);
 480   }
 481
 482   /// Remove all attributes at the specified arg index from this
 483   /// attribute list. Returns a new list because attribute lists are immutable.
 484   LLVM_NODISCARD AttributeList removeParamAttributes(LLVMContext &C,
 485                                                      unsigned ArgNo) const {
 486     return removeAttributes(C, ArgNo + FirstArgIndex);
 487   }
 488
 489   /// \brief Add the dereferenceable attribute to the attribute set at the given
 490   /// index. Returns a new list because attribute lists are immutable.
 491   LLVM_NODISCARD AttributeList addDereferenceableAttr(LLVMContext &C,
 492                                                       unsigned Index,
 493                                                       uint64_t Bytes) const;
 494
 495   /// \brief Add the dereferenceable attribute to the attribute set at the given
 496   /// arg index. Returns a new list because attribute lists are immutable.
 497   LLVM_NODISCARD AttributeList addDereferenceableParamAttr(
 498       LLVMContext &C, unsigned ArgNo, uint64_t Bytes) const {
 499     return addDereferenceableAttr(C, ArgNo + FirstArgIndex, Bytes);
 500   }
 501
 502   /// Add the dereferenceable_or_null attribute to the attribute set at
 503   /// the given index. Returns a new list because attribute lists are immutable.
 504   LLVM_NODISCARD AttributeList addDereferenceableOrNullAttr(
 505       LLVMContext &C, unsigned Index, uint64_t Bytes) const;
 506
 507   /// Add the dereferenceable_or_null attribute to the attribute set at
 508   /// the given arg index. Returns a new list because attribute lists are
 509   /// immutable.
 510   LLVM_NODISCARD AttributeList addDereferenceableOrNullParamAttr(
 511       LLVMContext &C, unsigned ArgNo, uint64_t Bytes) const {
 512     return addDereferenceableOrNullAttr(C, ArgNo + FirstArgIndex, Bytes);
 513   }
 514
 515   /// Add the allocsize attribute to the attribute set at the given index.
 516   /// Returns a new list because attribute lists are immutable.
 517   LLVM_NODISCARD AttributeList
 518   addAllocSizeAttr(LLVMContext &C, unsigned Index, unsigned ElemSizeArg,
 519                    const Optional<unsigned> &NumElemsArg);
 520
 521   /// Add the allocsize attribute to the attribute set at the given arg index.
 522   /// Returns a new list because attribute lists are immutable.
 523   LLVM_NODISCARD AttributeList
 524   addAllocSizeParamAttr(LLVMContext &C, unsigned ArgNo, unsigned ElemSizeArg,
 525                         const Optional<unsigned> &NumElemsArg) {
 526     return addAllocSizeAttr(C, ArgNo + FirstArgIndex, ElemSizeArg, NumElemsArg);
 527   }
 528
 529   //===--------------------------------------------------------------------===//
 530   // AttributeList Accessors
 531   //===--------------------------------------------------------------------===//
 532
 533   /// Retrieve the LLVM context.
 534   LLVMContext &getContext() const;
 535
 536   /// The attributes for the specified index are returned.
 537   AttributeSet getAttributes(unsigned Index) const;
 538
 539   /// The attributes for the argument or parameter at the given index are
 540   /// returned.
 541   AttributeSet getParamAttributes(unsigned ArgNo) const;
 542
 543   /// The attributes for the ret value are returned.
 544   AttributeSet getRetAttributes() const;
 545
 546   /// The function attributes are returned.
 547   AttributeSet getFnAttributes() const;
 548
 549   /// Return true if the attribute exists at the given index.
 550   bool hasAttribute(unsigned Index, Attribute::AttrKind Kind) const;
 551
 552   /// Return true if the attribute exists at the given index.
 553   bool hasAttribute(unsigned Index, StringRef Kind) const;
 554
 555   /// Return true if attribute exists at the given index.
 556   bool hasAttributes(unsigned Index) const;
 557
 558   /// Return true if the attribute exists for the given argument
 559   bool hasParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) const {
 560     return hasAttribute(ArgNo + FirstArgIndex, Kind);
 561   }
 562
 563   /// Return true if the attribute exists for the given argument
 564   bool hasParamAttr(unsigned ArgNo, StringRef Kind) const {
 565     return hasAttribute(ArgNo + FirstArgIndex, Kind);
 566   }
 567
 568   /// Return true if attributes exists for the given argument
 569   bool hasParamAttrs(unsigned ArgNo) const {
 570     return hasAttributes(ArgNo + FirstArgIndex);
 571   }
 572
 573   /// Equivalent to hasAttribute(AttributeList::FunctionIndex, Kind) but
 574   /// may be faster.
 575   bool hasFnAttribute(Attribute::AttrKind Kind) const;
 576
 577   /// Equivalent to hasAttribute(AttributeList::FunctionIndex, Kind) but
 578   /// may be faster.
 579   bool hasFnAttribute(StringRef Kind) const;
 580
 581   /// Equivalent to hasAttribute(ArgNo + FirstArgIndex, Kind).
 582   bool hasParamAttribute(unsigned ArgNo, Attribute::AttrKind Kind) const;
 583
 584   /// Return true if the specified attribute is set for at least one
 585   /// parameter or for the return value. If Index is not nullptr, the index
 586   /// of a parameter with the specified attribute is provided.
 587   bool hasAttrSomewhere(Attribute::AttrKind Kind,
 588                         unsigned *Index = nullptr) const;
 589
 590   /// Return the attribute object that exists at the given index.
 591   Attribute getAttribute(unsigned Index, Attribute::AttrKind Kind) const;
 592
 593   /// Return the attribute object that exists at the given index.
 594   Attribute getAttribute(unsigned Index, StringRef Kind) const;
 595
 596   /// Return the attribute object that exists at the arg index.
 597   Attribute getParamAttr(unsigned ArgNo, Attribute::AttrKind Kind) const {
 598     return getAttribute(ArgNo + FirstArgIndex, Kind);
 599   }
 600
 601   /// Return the attribute object that exists at the given index.
 602   Attribute getParamAttr(unsigned ArgNo, StringRef Kind) const {
 603     return getAttribute(ArgNo + FirstArgIndex, Kind);
 604   }
 605
 606   /// Return the alignment of the return value.
 607   MaybeAlign getRetAlignment() const;
 608
 609   /// Return the alignment for the specified function parameter.
 610   MaybeAlign getParamAlignment(unsigned ArgNo) const;
 611
 612   /// Return the byval type for the specified function parameter.
 613   Type *getParamByValType(unsigned ArgNo) const;
 614
 615   /// Get the stack alignment.
 616   MaybeAlign getStackAlignment(unsigned Index) const;
 617
 618   /// Get the number of dereferenceable bytes (or zero if unknown).
 619   uint64_t getDereferenceableBytes(unsigned Index) const;
 620
 621   /// Get the number of dereferenceable bytes (or zero if unknown) of an
 622   /// arg.
 623   uint64_t getParamDereferenceableBytes(unsigned ArgNo) const {
 624     return getDereferenceableBytes(ArgNo + FirstArgIndex);
 625   }
 626
 627   /// Get the number of dereferenceable_or_null bytes (or zero if
 628   /// unknown).
 629   uint64_t getDereferenceableOrNullBytes(unsigned Index) const;
 630
 631   /// Get the number of dereferenceable_or_null bytes (or zero if
 632   /// unknown) of an arg.
 633   uint64_t getParamDereferenceableOrNullBytes(unsigned ArgNo) const {
 634     return getDereferenceableOrNullBytes(ArgNo + FirstArgIndex);
 635   }
 636
 637   /// Get the allocsize argument numbers (or pair(0, 0) if unknown).
 638   std::pair<unsigned, Optional<unsigned>>
 639   getAllocSizeArgs(unsigned Index) const;
 640
 641   /// Return the attributes at the index as a string.
 642   std::string getAsString(unsigned Index, bool InAttrGrp = false) const;
 643
 644   //===--------------------------------------------------------------------===//
 645   // AttributeList Introspection
 646   //===--------------------------------------------------------------------===//
 647
 648   using iterator = const AttributeSet *;
 649
 650   iterator begin() const;
 651   iterator end() const;
 652
 653   unsigned getNumAttrSets() const;
 654
 655   /// Use these to iterate over the valid attribute indices.
 656   unsigned index_begin() const { return AttributeList::FunctionIndex; }
 657   unsigned index_end() const { return getNumAttrSets() - 1; }
 658
 659   /// operator==/!= - Provide equality predicates.
 660   bool operator==(const AttributeList &RHS) const { return pImpl == RHS.pImpl; }
 661   bool operator!=(const AttributeList &RHS) const { return pImpl != RHS.pImpl; }
 662
 663   /// Return a raw pointer that uniquely identifies this attribute list.
 664   void *getRawPointer() const {
 665     return pImpl;
 666   }
 667
 668   /// Return true if there are no attributes.
 669   bool isEmpty() const { return pImpl == nullptr; }
 670
 671   void dump() const;
 672 };
 673
 674 //===----------------------------------------------------------------------===//
 675 /// \class
 676 /// Provide DenseMapInfo for AttributeList.
 677 template <> struct DenseMapInfo<AttributeList> {
 678   static AttributeList getEmptyKey() {
 679     auto Val = static_cast<uintptr_t>(-1);
 680     Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
 681     return AttributeList(reinterpret_cast<AttributeListImpl *>(Val));
 682   }
 683
 684   static AttributeList getTombstoneKey() {
 685     auto Val = static_cast<uintptr_t>(-2);
 686     Val <<= PointerLikeTypeTraits<void*>::NumLowBitsAvailable;
 687     return AttributeList(reinterpret_cast<AttributeListImpl *>(Val));
 688   }
 689
 690   static unsigned getHashValue(AttributeList AS) {
 691     return (unsigned((uintptr_t)AS.pImpl) >> 4) ^
 692            (unsigned((uintptr_t)AS.pImpl) >> 9);
 693   }
 694
 695   static bool isEqual(AttributeList LHS, AttributeList RHS) {
 696     return LHS == RHS;
 697   }
 698 };
 699
 700 //===----------------------------------------------------------------------===//
 701 /// \class
 702 /// This class is used in conjunction with the Attribute::get method to
 703 /// create an Attribute object. The object itself is uniquified. The Builder's
 704 /// value, however, is not. So this can be used as a quick way to test for
 705 /// equality, presence of attributes, etc.
 706 class AttrBuilder {
 707   std::bitset<Attribute::EndAttrKinds> Attrs;
 708   std::map<std::string, std::string, std::less<>> TargetDepAttrs;
 709   MaybeAlign Alignment;
 710   MaybeAlign StackAlignment;
 711   uint64_t DerefBytes = 0;
 712   uint64_t DerefOrNullBytes = 0;
 713   uint64_t AllocSizeArgs = 0;
 714   Type *ByValType = nullptr;
 715
 716 public:
 717   AttrBuilder() = default;
 718
 719   AttrBuilder(const Attribute &A) {
 720     addAttribute(A);
 721   }
 722
 723   AttrBuilder(AttributeList AS, unsigned Idx);
 724   AttrBuilder(AttributeSet AS);
 725
 726   void clear();
 727
 728   /// Add an attribute to the builder.
 729   AttrBuilder &addAttribute(Attribute::AttrKind Val);
 730
 731   /// Add the Attribute object to the builder.
 732   AttrBuilder &addAttribute(Attribute A);
 733
 734   /// Add the target-dependent attribute to the builder.
 735   AttrBuilder &addAttribute(StringRef A, StringRef V = StringRef());
 736
 737   /// Remove an attribute from the builder.
 738   AttrBuilder &removeAttribute(Attribute::AttrKind Val);
 739
 740   /// Remove the attributes from the builder.
 741   AttrBuilder &removeAttributes(AttributeList A, uint64_t WithoutIndex);
 742
 743   /// Remove the target-dependent attribute to the builder.
 744   AttrBuilder &removeAttribute(StringRef A);
 745
 746   /// Add the attributes from the builder.
 747   AttrBuilder &merge(const AttrBuilder &B);
 748
 749   /// Remove the attributes from the builder.
 750   AttrBuilder &remove(const AttrBuilder &B);
 751
 752   /// Return true if the builder has any attribute that's in the
 753   /// specified builder.
 754   bool overlaps(const AttrBuilder &B) const;
 755
 756   /// Return true if the builder has the specified attribute.
 757   bool contains(Attribute::AttrKind A) const {
 758     assert((unsigned)A < Attribute::EndAttrKinds && "Attribute out of range!");
 759     return Attrs[A];
 760   }
 761
 762   /// Return true if the builder has the specified target-dependent
 763   /// attribute.
 764   bool contains(StringRef A) const;
 765
 766   /// Return true if the builder has IR-level attributes.
 767   bool hasAttributes() const;
 768
 769   /// Return true if the builder has any attribute that's in the
 770   /// specified attribute.
 771   bool hasAttributes(AttributeList A, uint64_t Index) const;
 772
 773   /// Return true if the builder has an alignment attribute.
 774   bool hasAlignmentAttr() const;
 775
 776   /// Retrieve the alignment attribute, if it exists.
 777   MaybeAlign getAlignment() const { return Alignment; }
 778
 779   /// Retrieve the stack alignment attribute, if it exists.
 780   MaybeAlign getStackAlignment() const { return StackAlignment; }
 781
 782   /// Retrieve the number of dereferenceable bytes, if the
 783   /// dereferenceable attribute exists (zero is returned otherwise).
 784   uint64_t getDereferenceableBytes() const { return DerefBytes; }
 785
 786   /// Retrieve the number of dereferenceable_or_null bytes, if the
 787   /// dereferenceable_or_null attribute exists (zero is returned otherwise).
 788   uint64_t getDereferenceableOrNullBytes() const { return DerefOrNullBytes; }
 789
 790   /// Retrieve the byval type.
 791   Type *getByValType() const { return ByValType; }
 792
 793   /// Retrieve the allocsize args, if the allocsize attribute exists.  If it
 794   /// doesn't exist, pair(0, 0) is returned.
 795   std::pair<unsigned, Optional<unsigned>> getAllocSizeArgs() const;
 796
 797   /// This turns an alignment into the form used internally in Attribute.
 798   /// This call has no effect if Align is not set.
 799   AttrBuilder &addAlignmentAttr(MaybeAlign Align);
 800
 801   /// This turns an int alignment (which must be a power of 2) into the
 802   /// form used internally in Attribute.
 803   /// This call has no effect if Align is 0.
 804   /// Deprecated, use the version using a MaybeAlign.
 805   inline AttrBuilder &addAlignmentAttr(unsigned Align) {
 806     return addAlignmentAttr(MaybeAlign(Align));
 807   }
 808
 809   /// This turns a stack alignment into the form used internally in Attribute.
 810   /// This call has no effect if Align is not set.
 811   AttrBuilder &addStackAlignmentAttr(MaybeAlign Align);
 812
 813   /// This turns an int stack alignment (which must be a power of 2) into
 814   /// the form used internally in Attribute.
 815   /// This call has no effect if Align is 0.
 816   /// Deprecated, use the version using a MaybeAlign.
 817   inline AttrBuilder &addStackAlignmentAttr(unsigned Align) {
 818     return addStackAlignmentAttr(MaybeAlign(Align));
 819   }
 820
 821   /// This turns the number of dereferenceable bytes into the form used
 822   /// internally in Attribute.
 823   AttrBuilder &addDereferenceableAttr(uint64_t Bytes);
 824
 825   /// This turns the number of dereferenceable_or_null bytes into the
 826   /// form used internally in Attribute.
 827   AttrBuilder &addDereferenceableOrNullAttr(uint64_t Bytes);
 828
 829   /// This turns one (or two) ints into the form used internally in Attribute.
 830   AttrBuilder &addAllocSizeAttr(unsigned ElemSizeArg,
 831                                 const Optional<unsigned> &NumElemsArg);
 832
 833   /// This turns a byval type into the form used internally in Attribute.
 834   AttrBuilder &addByValAttr(Type *Ty);
 835
 836   /// Add an allocsize attribute, using the representation returned by
 837   /// Attribute.getIntValue().
 838   AttrBuilder &addAllocSizeAttrFromRawRepr(uint64_t RawAllocSizeRepr);
 839
 840   /// Return true if the builder contains no target-independent
 841   /// attributes.
 842   bool empty() const { return Attrs.none(); }
 843
 844   // Iterators for target-dependent attributes.
 845   using td_type = std::pair<std::string, std::string>;
 846   using td_iterator = std::map<std::string, std::string>::iterator;
 847   using td_const_iterator = std::map<std::string, std::string>::const_iterator;
 848   using td_range = iterator_range<td_iterator>;
 849   using td_const_range = iterator_range<td_const_iterator>;
 850
 851   td_iterator td_begin() { return TargetDepAttrs.begin(); }
 852   td_iterator td_end() { return TargetDepAttrs.end(); }
 853
 854   td_const_iterator td_begin() const { return TargetDepAttrs.begin(); }
 855   td_const_iterator td_end() const { return TargetDepAttrs.end(); }
 856
 857   td_range td_attrs() { return td_range(td_begin(), td_end()); }
 858
 859   td_const_range td_attrs() const {
 860     return td_const_range(td_begin(), td_end());
 861   }
 862
 863   bool td_empty() const { return TargetDepAttrs.empty(); }
 864
 865   bool operator==(const AttrBuilder &B);
 866   bool operator!=(const AttrBuilder &B) {
 867     return !(*this == B);
 868   }
 869 };
 870
 871 namespace AttributeFuncs {
 872
 873 /// Which attributes cannot be applied to a type.
 874 AttrBuilder typeIncompatible(Type *Ty);
 875
 876 /// \returns Return true if the two functions have compatible target-independent
 877 /// attributes for inlining purposes.
 878 bool areInlineCompatible(const Function &Caller, const Function &Callee);
 879
 880 /// Merge caller's and callee's attributes.
 881 void mergeAttributesForInlining(Function &Caller, const Function &Callee);
 882
 883 } // end namespace AttributeFuncs
 884
 885 } // end namespace llvm
 886
 887 #endif // LLVM_IR_ATTRIBUTES_H