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