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      1 //===-- AttributeImpl.h - Attribute Internals -------------------*- 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 defines various helper methods and classes used by
     12 /// LLVMContextImpl for creating and managing attributes.
     13 ///
     14 //===----------------------------------------------------------------------===//
     15 
     16 #ifndef LLVM_LIB_IR_ATTRIBUTEIMPL_H
     17 #define LLVM_LIB_IR_ATTRIBUTEIMPL_H
     18 
     19 #include "llvm/ADT/FoldingSet.h"
     20 #include "llvm/IR/Attributes.h"
     21 #include <string>
     22 
     23 namespace llvm {
     24 
     25 class Constant;
     26 class LLVMContext;
     27 
     28 //===----------------------------------------------------------------------===//
     29 /// \class
     30 /// \brief This class represents a single, uniqued attribute. That attribute
     31 /// could be a single enum, a tuple, or a string.
     32 class AttributeImpl : public FoldingSetNode {
     33   unsigned char KindID; ///< Holds the AttrEntryKind of the attribute
     34 
     35   // AttributesImpl is uniqued, these should not be publicly available.
     36   void operator=(const AttributeImpl &) = delete;
     37   AttributeImpl(const AttributeImpl &) = delete;
     38 
     39 protected:
     40   enum AttrEntryKind {
     41     EnumAttrEntry,
     42     IntAttrEntry,
     43     StringAttrEntry
     44   };
     45 
     46   AttributeImpl(AttrEntryKind KindID) : KindID(KindID) {}
     47 
     48 public:
     49   virtual ~AttributeImpl();
     50 
     51   bool isEnumAttribute() const { return KindID == EnumAttrEntry; }
     52   bool isIntAttribute() const { return KindID == IntAttrEntry; }
     53   bool isStringAttribute() const { return KindID == StringAttrEntry; }
     54 
     55   bool hasAttribute(Attribute::AttrKind A) const;
     56   bool hasAttribute(StringRef Kind) const;
     57 
     58   Attribute::AttrKind getKindAsEnum() const;
     59   uint64_t getValueAsInt() const;
     60 
     61   StringRef getKindAsString() const;
     62   StringRef getValueAsString() const;
     63 
     64   /// \brief Used when sorting the attributes.
     65   bool operator<(const AttributeImpl &AI) const;
     66 
     67   void Profile(FoldingSetNodeID &ID) const {
     68     if (isEnumAttribute())
     69       Profile(ID, getKindAsEnum(), 0);
     70     else if (isIntAttribute())
     71       Profile(ID, getKindAsEnum(), getValueAsInt());
     72     else
     73       Profile(ID, getKindAsString(), getValueAsString());
     74   }
     75   static void Profile(FoldingSetNodeID &ID, Attribute::AttrKind Kind,
     76                       uint64_t Val) {
     77     ID.AddInteger(Kind);
     78     if (Val) ID.AddInteger(Val);
     79   }
     80   static void Profile(FoldingSetNodeID &ID, StringRef Kind, StringRef Values) {
     81     ID.AddString(Kind);
     82     if (!Values.empty()) ID.AddString(Values);
     83   }
     84 
     85   // FIXME: Remove this!
     86   static uint64_t getAttrMask(Attribute::AttrKind Val);
     87 };
     88 
     89 //===----------------------------------------------------------------------===//
     90 /// \class
     91 /// \brief A set of classes that contain the value of the
     92 /// attribute object. There are three main categories: enum attribute entries,
     93 /// represented by Attribute::AttrKind; alignment attribute entries; and string
     94 /// attribute enties, which are for target-dependent attributes.
     95 
     96 class EnumAttributeImpl : public AttributeImpl {
     97   virtual void anchor();
     98   Attribute::AttrKind Kind;
     99 
    100 protected:
    101   EnumAttributeImpl(AttrEntryKind ID, Attribute::AttrKind Kind)
    102       : AttributeImpl(ID), Kind(Kind) {}
    103 
    104 public:
    105   EnumAttributeImpl(Attribute::AttrKind Kind)
    106       : AttributeImpl(EnumAttrEntry), Kind(Kind) {}
    107 
    108   Attribute::AttrKind getEnumKind() const { return Kind; }
    109 };
    110 
    111 class IntAttributeImpl : public EnumAttributeImpl {
    112   void anchor() override;
    113   uint64_t Val;
    114 
    115 public:
    116   IntAttributeImpl(Attribute::AttrKind Kind, uint64_t Val)
    117       : EnumAttributeImpl(IntAttrEntry, Kind), Val(Val) {
    118     assert((Kind == Attribute::Alignment || Kind == Attribute::StackAlignment ||
    119             Kind == Attribute::Dereferenceable ||
    120             Kind == Attribute::DereferenceableOrNull) &&
    121            "Wrong kind for int attribute!");
    122   }
    123 
    124   uint64_t getValue() const { return Val; }
    125 };
    126 
    127 class StringAttributeImpl : public AttributeImpl {
    128   virtual void anchor();
    129   std::string Kind;
    130   std::string Val;
    131 
    132 public:
    133   StringAttributeImpl(StringRef Kind, StringRef Val = StringRef())
    134       : AttributeImpl(StringAttrEntry), Kind(Kind), Val(Val) {}
    135 
    136   StringRef getStringKind() const { return Kind; }
    137   StringRef getStringValue() const { return Val; }
    138 };
    139 
    140 //===----------------------------------------------------------------------===//
    141 /// \class
    142 /// \brief This class represents a group of attributes that apply to one
    143 /// element: function, return type, or parameter.
    144 class AttributeSetNode : public FoldingSetNode {
    145   unsigned NumAttrs; ///< Number of attributes in this node.
    146 
    147   AttributeSetNode(ArrayRef<Attribute> Attrs) : NumAttrs(Attrs.size()) {
    148     // There's memory after the node where we can store the entries in.
    149     std::copy(Attrs.begin(), Attrs.end(),
    150               reinterpret_cast<Attribute *>(this + 1));
    151   }
    152 
    153   // AttributesSetNode is uniqued, these should not be publicly available.
    154   void operator=(const AttributeSetNode &) = delete;
    155   AttributeSetNode(const AttributeSetNode &) = delete;
    156 public:
    157   static AttributeSetNode *get(LLVMContext &C, ArrayRef<Attribute> Attrs);
    158 
    159   bool hasAttribute(Attribute::AttrKind Kind) const;
    160   bool hasAttribute(StringRef Kind) const;
    161   bool hasAttributes() const { return NumAttrs != 0; }
    162 
    163   Attribute getAttribute(Attribute::AttrKind Kind) const;
    164   Attribute getAttribute(StringRef Kind) const;
    165 
    166   unsigned getAlignment() const;
    167   unsigned getStackAlignment() const;
    168   uint64_t getDereferenceableBytes() const;
    169   std::string getAsString(bool InAttrGrp) const;
    170 
    171   typedef const Attribute *iterator;
    172   iterator begin() const { return reinterpret_cast<iterator>(this + 1); }
    173   iterator end() const { return begin() + NumAttrs; }
    174 
    175   void Profile(FoldingSetNodeID &ID) const {
    176     Profile(ID, makeArrayRef(begin(), end()));
    177   }
    178   static void Profile(FoldingSetNodeID &ID, ArrayRef<Attribute> AttrList) {
    179     for (unsigned I = 0, E = AttrList.size(); I != E; ++I)
    180       AttrList[I].Profile(ID);
    181   }
    182 };
    183 
    184 //===----------------------------------------------------------------------===//
    185 /// \class
    186 /// \brief This class represents a set of attributes that apply to the function,
    187 /// return type, and parameters.
    188 class AttributeSetImpl : public FoldingSetNode {
    189   friend class AttributeSet;
    190 
    191   LLVMContext &Context;
    192 
    193   typedef std::pair<unsigned, AttributeSetNode*> IndexAttrPair;
    194   unsigned NumAttrs; ///< Number of entries in this set.
    195 
    196   /// \brief Return a pointer to the IndexAttrPair for the specified slot.
    197   const IndexAttrPair *getNode(unsigned Slot) const {
    198     return reinterpret_cast<const IndexAttrPair *>(this + 1) + Slot;
    199   }
    200 
    201   // AttributesSet is uniqued, these should not be publicly available.
    202   void operator=(const AttributeSetImpl &) = delete;
    203   AttributeSetImpl(const AttributeSetImpl &) = delete;
    204 public:
    205   AttributeSetImpl(LLVMContext &C,
    206                    ArrayRef<std::pair<unsigned, AttributeSetNode *> > Attrs)
    207       : Context(C), NumAttrs(Attrs.size()) {
    208 #ifndef NDEBUG
    209     if (Attrs.size() >= 2) {
    210       for (const std::pair<unsigned, AttributeSetNode *> *i = Attrs.begin() + 1,
    211                                                          *e = Attrs.end();
    212            i != e; ++i) {
    213         assert((i-1)->first <= i->first && "Attribute set not ordered!");
    214       }
    215     }
    216 #endif
    217     // There's memory after the node where we can store the entries in.
    218     std::copy(Attrs.begin(), Attrs.end(),
    219               reinterpret_cast<IndexAttrPair *>(this + 1));
    220   }
    221 
    222   /// \brief Get the context that created this AttributeSetImpl.
    223   LLVMContext &getContext() { return Context; }
    224 
    225   /// \brief Return the number of attributes this AttributeSet contains.
    226   unsigned getNumAttributes() const { return NumAttrs; }
    227 
    228   /// \brief Get the index of the given "slot" in the AttrNodes list. This index
    229   /// is the index of the return, parameter, or function object that the
    230   /// attributes are applied to, not the index into the AttrNodes list where the
    231   /// attributes reside.
    232   unsigned getSlotIndex(unsigned Slot) const {
    233     return getNode(Slot)->first;
    234   }
    235 
    236   /// \brief Retrieve the attributes for the given "slot" in the AttrNode list.
    237   /// \p Slot is an index into the AttrNodes list, not the index of the return /
    238   /// parameter/ function which the attributes apply to.
    239   AttributeSet getSlotAttributes(unsigned Slot) const {
    240     return AttributeSet::get(Context, *getNode(Slot));
    241   }
    242 
    243   /// \brief Retrieve the attribute set node for the given "slot" in the
    244   /// AttrNode list.
    245   AttributeSetNode *getSlotNode(unsigned Slot) const {
    246     return getNode(Slot)->second;
    247   }
    248 
    249   typedef AttributeSetNode::iterator iterator;
    250   iterator begin(unsigned Slot) const { return getSlotNode(Slot)->begin(); }
    251   iterator end(unsigned Slot) const { return getSlotNode(Slot)->end(); }
    252 
    253   void Profile(FoldingSetNodeID &ID) const {
    254     Profile(ID, makeArrayRef(getNode(0), getNumAttributes()));
    255   }
    256   static void Profile(FoldingSetNodeID &ID,
    257                       ArrayRef<std::pair<unsigned, AttributeSetNode*> > Nodes) {
    258     for (unsigned i = 0, e = Nodes.size(); i != e; ++i) {
    259       ID.AddInteger(Nodes[i].first);
    260       ID.AddPointer(Nodes[i].second);
    261     }
    262   }
    263 
    264   // FIXME: This atrocity is temporary.
    265   uint64_t Raw(unsigned Index) const;
    266 
    267   void dump() const;
    268 };
    269 
    270 } // end llvm namespace
    271 
    272 #endif
    273