1 //===- AttributeImpl.h - Attribute Internals --------------------*- 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 defines various helper methods and classes used by
11 /// LLVMContextImpl for creating and managing attributes.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_LIB_IR_ATTRIBUTEIMPL_H
16 #define LLVM_LIB_IR_ATTRIBUTEIMPL_H
17 
18 #include "llvm/ADT/ArrayRef.h"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/ADT/FoldingSet.h"
21 #include "llvm/ADT/StringRef.h"
22 #include "llvm/IR/Attributes.h"
23 #include "llvm/Support/TrailingObjects.h"
24 #include <cassert>
25 #include <cstddef>
26 #include <cstdint>
27 #include <string>
28 #include <utility>
29 
30 namespace llvm {
31 
32 class LLVMContext;
33 class Type;
34 
35 //===----------------------------------------------------------------------===//
36 /// \class
37 /// This class represents a single, uniqued attribute. That attribute
38 /// could be a single enum, a tuple, or a string.
39 class AttributeImpl : public FoldingSetNode {
40   unsigned char KindID; ///< Holds the AttrEntryKind of the attribute
41 
42 protected:
43   enum AttrEntryKind {
44     EnumAttrEntry,
45     IntAttrEntry,
46     StringAttrEntry,
47     TypeAttrEntry,
48   };
49 
50   AttributeImpl(AttrEntryKind KindID) : KindID(KindID) {}
51 
52 public:
53   // AttributesImpl is uniqued, these should not be available.
54   AttributeImpl(const AttributeImpl &) = delete;
55   AttributeImpl &operator=(const AttributeImpl &) = delete;
56 
57   bool isEnumAttribute() const { return KindID == EnumAttrEntry; }
58   bool isIntAttribute() const { return KindID == IntAttrEntry; }
59   bool isStringAttribute() const { return KindID == StringAttrEntry; }
60   bool isTypeAttribute() const { return KindID == TypeAttrEntry; }
61 
62   bool hasAttribute(Attribute::AttrKind A) const;
63   bool hasAttribute(StringRef Kind) const;
64 
65   Attribute::AttrKind getKindAsEnum() const;
66   uint64_t getValueAsInt() const;
67   bool getValueAsBool() const;
68 
69   StringRef getKindAsString() const;
70   StringRef getValueAsString() const;
71 
72   Type *getValueAsType() const;
73 
74   /// Used when sorting the attributes.
75   bool operator<(const AttributeImpl &AI) const;
76 
77   void Profile(FoldingSetNodeID &ID) const {
78     if (isEnumAttribute())
79       Profile(ID, getKindAsEnum(), static_cast<uint64_t>(0));
80     else if (isIntAttribute())
81       Profile(ID, getKindAsEnum(), getValueAsInt());
82     else if (isStringAttribute())
83       Profile(ID, getKindAsString(), getValueAsString());
84     else
85       Profile(ID, getKindAsEnum(), getValueAsType());
86   }
87 
88   static void Profile(FoldingSetNodeID &ID, Attribute::AttrKind Kind,
89                       uint64_t Val) {
90     ID.AddInteger(Kind);
91     if (Val) ID.AddInteger(Val);
92   }
93 
94   static void Profile(FoldingSetNodeID &ID, StringRef Kind, StringRef Values) {
95     ID.AddString(Kind);
96     if (!Values.empty()) ID.AddString(Values);
97   }
98 
99   static void Profile(FoldingSetNodeID &ID, Attribute::AttrKind Kind,
100                       Type *Ty) {
101     ID.AddInteger(Kind);
102     ID.AddPointer(Ty);
103   }
104 };
105 
106 static_assert(std::is_trivially_destructible<AttributeImpl>::value,
107               "AttributeImpl should be trivially destructible");
108 
109 //===----------------------------------------------------------------------===//
110 /// \class
111 /// A set of classes that contain the value of the
112 /// attribute object. There are three main categories: enum attribute entries,
113 /// represented by Attribute::AttrKind; alignment attribute entries; and string
114 /// attribute enties, which are for target-dependent attributes.
115 
116 class EnumAttributeImpl : public AttributeImpl {
117   Attribute::AttrKind Kind;
118 
119 protected:
120   EnumAttributeImpl(AttrEntryKind ID, Attribute::AttrKind Kind)
121       : AttributeImpl(ID), Kind(Kind) {}
122 
123 public:
124   EnumAttributeImpl(Attribute::AttrKind Kind)
125       : AttributeImpl(EnumAttrEntry), Kind(Kind) {
126     assert(Kind != Attribute::AttrKind::None &&
127            "Can't create a None attribute!");
128   }
129 
130   Attribute::AttrKind getEnumKind() const { return Kind; }
131 };
132 
133 class IntAttributeImpl : public EnumAttributeImpl {
134   uint64_t Val;
135 
136 public:
137   IntAttributeImpl(Attribute::AttrKind Kind, uint64_t Val)
138       : EnumAttributeImpl(IntAttrEntry, Kind), Val(Val) {
139     assert(Attribute::isIntAttrKind(Kind) &&
140            "Wrong kind for int attribute!");
141   }
142 
143   uint64_t getValue() const { return Val; }
144 };
145 
146 class StringAttributeImpl final
147     : public AttributeImpl,
148       private TrailingObjects<StringAttributeImpl, char> {
149   friend TrailingObjects;
150 
151   unsigned KindSize;
152   unsigned ValSize;
153   size_t numTrailingObjects(OverloadToken<char>) const {
154     return KindSize + 1 + ValSize + 1;
155   }
156 
157 public:
158   StringAttributeImpl(StringRef Kind, StringRef Val = StringRef())
159       : AttributeImpl(StringAttrEntry), KindSize(Kind.size()),
160         ValSize(Val.size()) {
161     char *TrailingString = getTrailingObjects<char>();
162     // Some users rely on zero-termination.
163     llvm::copy(Kind, TrailingString);
164     TrailingString[KindSize] = '\0';
165     llvm::copy(Val, &TrailingString[KindSize + 1]);
166     TrailingString[KindSize + 1 + ValSize] = '\0';
167   }
168 
169   StringRef getStringKind() const {
170     return StringRef(getTrailingObjects<char>(), KindSize);
171   }
172   StringRef getStringValue() const {
173     return StringRef(getTrailingObjects<char>() + KindSize + 1, ValSize);
174   }
175 
176   static size_t totalSizeToAlloc(StringRef Kind, StringRef Val) {
177     return TrailingObjects::totalSizeToAlloc<char>(Kind.size() + 1 +
178                                                    Val.size() + 1);
179   }
180 };
181 
182 class TypeAttributeImpl : public EnumAttributeImpl {
183   Type *Ty;
184 
185 public:
186   TypeAttributeImpl(Attribute::AttrKind Kind, Type *Ty)
187       : EnumAttributeImpl(TypeAttrEntry, Kind), Ty(Ty) {}
188 
189   Type *getTypeValue() const { return Ty; }
190 };
191 
192 class AttributeBitSet {
193   /// Bitset with a bit for each available attribute Attribute::AttrKind.
194   uint8_t AvailableAttrs[12] = {};
195   static_assert(Attribute::EndAttrKinds <= sizeof(AvailableAttrs) * CHAR_BIT,
196                 "Too many attributes");
197 
198 public:
199   bool hasAttribute(Attribute::AttrKind Kind) const {
200     return AvailableAttrs[Kind / 8] & (1 << (Kind % 8));
201   }
202 
203   void addAttribute(Attribute::AttrKind Kind) {
204     AvailableAttrs[Kind / 8] |= 1 << (Kind % 8);
205   }
206 };
207 
208 //===----------------------------------------------------------------------===//
209 /// \class
210 /// This class represents a group of attributes that apply to one
211 /// element: function, return type, or parameter.
212 class AttributeSetNode final
213     : public FoldingSetNode,
214       private TrailingObjects<AttributeSetNode, Attribute> {
215   friend TrailingObjects;
216 
217   unsigned NumAttrs; ///< Number of attributes in this node.
218   AttributeBitSet AvailableAttrs; ///< Available enum attributes.
219 
220   DenseMap<StringRef, Attribute> StringAttrs;
221 
222   AttributeSetNode(ArrayRef<Attribute> Attrs);
223 
224   static AttributeSetNode *getSorted(LLVMContext &C,
225                                      ArrayRef<Attribute> SortedAttrs);
226   Optional<Attribute> findEnumAttribute(Attribute::AttrKind Kind) const;
227 
228 public:
229   // AttributesSetNode is uniqued, these should not be available.
230   AttributeSetNode(const AttributeSetNode &) = delete;
231   AttributeSetNode &operator=(const AttributeSetNode &) = delete;
232 
233   void operator delete(void *p) { ::operator delete(p); }
234 
235   static AttributeSetNode *get(LLVMContext &C, const AttrBuilder &B);
236 
237   static AttributeSetNode *get(LLVMContext &C, ArrayRef<Attribute> Attrs);
238 
239   /// Return the number of attributes this AttributeList contains.
240   unsigned getNumAttributes() const { return NumAttrs; }
241 
242   bool hasAttribute(Attribute::AttrKind Kind) const {
243     return AvailableAttrs.hasAttribute(Kind);
244   }
245   bool hasAttribute(StringRef Kind) const;
246   bool hasAttributes() const { return NumAttrs != 0; }
247 
248   Attribute getAttribute(Attribute::AttrKind Kind) const;
249   Attribute getAttribute(StringRef Kind) const;
250 
251   MaybeAlign getAlignment() const;
252   MaybeAlign getStackAlignment() const;
253   uint64_t getDereferenceableBytes() const;
254   uint64_t getDereferenceableOrNullBytes() const;
255   std::pair<unsigned, Optional<unsigned>> getAllocSizeArgs() const;
256   unsigned getVScaleRangeMin() const;
257   Optional<unsigned> getVScaleRangeMax() const;
258   UWTableKind getUWTableKind() const;
259   AllocFnKind getAllocKind() const;
260   std::string getAsString(bool InAttrGrp) const;
261   Type *getAttributeType(Attribute::AttrKind Kind) const;
262 
263   using iterator = const Attribute *;
264 
265   iterator begin() const { return getTrailingObjects<Attribute>(); }
266   iterator end() const { return begin() + NumAttrs; }
267 
268   void Profile(FoldingSetNodeID &ID) const {
269     Profile(ID, makeArrayRef(begin(), end()));
270   }
271 
272   static void Profile(FoldingSetNodeID &ID, ArrayRef<Attribute> AttrList) {
273     for (const auto &Attr : AttrList)
274       Attr.Profile(ID);
275   }
276 };
277 
278 //===----------------------------------------------------------------------===//
279 /// \class
280 /// This class represents a set of attributes that apply to the function,
281 /// return type, and parameters.
282 class AttributeListImpl final
283     : public FoldingSetNode,
284       private TrailingObjects<AttributeListImpl, AttributeSet> {
285   friend class AttributeList;
286   friend TrailingObjects;
287 
288 private:
289   unsigned NumAttrSets; ///< Number of entries in this set.
290   /// Available enum function attributes.
291   AttributeBitSet AvailableFunctionAttrs;
292   /// Union of enum attributes available at any index.
293   AttributeBitSet AvailableSomewhereAttrs;
294 
295   // Helper fn for TrailingObjects class.
296   size_t numTrailingObjects(OverloadToken<AttributeSet>) { return NumAttrSets; }
297 
298 public:
299   AttributeListImpl(ArrayRef<AttributeSet> Sets);
300 
301   // AttributesSetImpt is uniqued, these should not be available.
302   AttributeListImpl(const AttributeListImpl &) = delete;
303   AttributeListImpl &operator=(const AttributeListImpl &) = delete;
304 
305   /// Return true if the AttributeSet or the FunctionIndex has an
306   /// enum attribute of the given kind.
307   bool hasFnAttribute(Attribute::AttrKind Kind) const {
308     return AvailableFunctionAttrs.hasAttribute(Kind);
309   }
310 
311   /// Return true if the specified attribute is set for at least one
312   /// parameter or for the return value. If Index is not nullptr, the index
313   /// of a parameter with the specified attribute is provided.
314   bool hasAttrSomewhere(Attribute::AttrKind Kind,
315                         unsigned *Index = nullptr) const;
316 
317   using iterator = const AttributeSet *;
318 
319   iterator begin() const { return getTrailingObjects<AttributeSet>(); }
320   iterator end() const { return begin() + NumAttrSets; }
321 
322   void Profile(FoldingSetNodeID &ID) const;
323   static void Profile(FoldingSetNodeID &ID, ArrayRef<AttributeSet> Nodes);
324 
325   void dump() const;
326 };
327 
328 static_assert(std::is_trivially_destructible<AttributeListImpl>::value,
329               "AttributeListImpl should be trivially destructible");
330 
331 } // end namespace llvm
332 
333 #endif // LLVM_LIB_IR_ATTRIBUTEIMPL_H
334