1 //===-- llvm/Metadata.h - Metadata definitions ------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// This file contains the declarations for metadata subclasses.
12 /// They represent the different flavors of metadata that live in LLVM.
14 //===----------------------------------------------------------------------===//
19 #include "llvm/User.h"
20 #include "llvm/Type.h"
21 #include "llvm/OperandTraits.h"
22 #include "llvm/ADT/FoldingSet.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/SmallPtrSet.h"
25 #include "llvm/ADT/ilist_node.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include "llvm/Support/ValueHandle.h"
33 //===----------------------------------------------------------------------===//
34 // MetadataBase - A base class for MDNode, MDString and NamedMDNode.
35 class MetadataBase : public User {
37 /// ReservedSpace - The number of operands actually allocated. NumOperands is
38 /// the number actually in use.
39 unsigned ReservedSpace;
42 MetadataBase(const Type *Ty, unsigned scid)
43 : User(Ty, scid, NULL, 0), ReservedSpace(0) {}
45 void resizeOperands(unsigned NumOps);
47 /// isNullValue - Return true if this is the value that would be returned by
48 /// getNullValue. This always returns false because getNullValue will never
50 virtual bool isNullValue() const {
54 /// Methods for support type inquiry through isa, cast, and dyn_cast:
55 static inline bool classof(const MetadataBase *) { return true; }
56 static bool classof(const Value *V) {
57 return V->getValueID() == MDStringVal || V->getValueID() == MDNodeVal
58 || V->getValueID() == NamedMDNodeVal;
62 //===----------------------------------------------------------------------===//
63 /// MDString - a single uniqued string.
64 /// These are used to efficiently contain a byte sequence for metadata.
65 /// MDString is always unnamd.
66 class MDString : public MetadataBase {
67 MDString(const MDString &); // DO NOT IMPLEMENT
68 void *operator new(size_t, unsigned); // DO NOT IMPLEMENT
69 unsigned getNumOperands(); // DO NOT IMPLEMENT
73 explicit MDString(LLVMContext &C, const char *begin, unsigned l)
74 : MetadataBase(Type::getMetadataTy(C), Value::MDStringVal), Str(begin, l) {}
77 // Do not allocate any space for operands.
78 void *operator new(size_t s) {
79 return User::operator new(s, 0);
81 static MDString *get(LLVMContext &Context, const StringRef &Str);
83 StringRef getString() const { return Str; }
85 unsigned length() const { return Str.size(); }
87 /// begin() - Pointer to the first byte of the string.
89 const char *begin() const { return Str.begin(); }
91 /// end() - Pointer to one byte past the end of the string.
93 const char *end() const { return Str.end(); }
95 /// Methods for support type inquiry through isa, cast, and dyn_cast:
96 static inline bool classof(const MDString *) { return true; }
97 static bool classof(const Value *V) {
98 return V->getValueID() == MDStringVal;
102 //===----------------------------------------------------------------------===//
103 /// MDNode - a tuple of other values.
104 /// These contain a list of the values that represent the metadata.
105 /// MDNode is always unnamed.
106 class MDNode : public MetadataBase, public FoldingSetNode {
107 MDNode(const MDNode &); // DO NOT IMPLEMENT
108 void *operator new(size_t, unsigned); // DO NOT IMPLEMENT
109 // getNumOperands - Make this only available for private uses.
110 unsigned getNumOperands() { return User::getNumOperands(); }
112 friend class ElementVH;
113 // Use CallbackVH to hold MDNOde elements.
114 struct ElementVH : public CallbackVH {
116 ElementVH(Value *V, MDNode *P) : CallbackVH(V), Parent(P) {}
119 virtual void deleted() {
120 Parent->replaceElement(this->operator Value*(), 0);
123 virtual void allUsesReplacedWith(Value *NV) {
124 Parent->replaceElement(this->operator Value*(), NV);
127 // Replace each instance of F from the element list of this node with T.
128 void replaceElement(Value *F, Value *T);
130 SmallVector<ElementVH, 4> Node;
133 explicit MDNode(LLVMContext &C, Value*const* Vals, unsigned NumVals);
135 // Do not allocate any space for operands.
136 void *operator new(size_t s) {
137 return User::operator new(s, 0);
139 // Constructors and destructors.
140 static MDNode *get(LLVMContext &Context,
141 Value* const* Vals, unsigned NumVals);
143 /// dropAllReferences - Remove all uses and clear node vector.
144 void dropAllReferences();
146 /// ~MDNode - Destroy MDNode.
149 /// getElement - Return specified element.
150 Value *getElement(unsigned i) const {
151 assert (getNumElements() > i && "Invalid element number!");
155 /// getNumElements - Return number of MDNode elements.
156 unsigned getNumElements() const {
161 typedef SmallVectorImpl<ElementVH>::const_iterator const_elem_iterator;
162 typedef SmallVectorImpl<ElementVH>::iterator elem_iterator;
163 /// elem_empty - Return true if MDNode is empty.
164 bool elem_empty() const { return Node.empty(); }
165 const_elem_iterator elem_begin() const { return Node.begin(); }
166 const_elem_iterator elem_end() const { return Node.end(); }
167 elem_iterator elem_begin() { return Node.begin(); }
168 elem_iterator elem_end() { return Node.end(); }
170 /// isNullValue - Return true if this is the value that would be returned by
171 /// getNullValue. This always returns false because getNullValue will never
172 /// produce metadata.
173 virtual bool isNullValue() const {
177 /// Profile - calculate a unique identifier for this MDNode to collapse
179 void Profile(FoldingSetNodeID &ID) const;
181 virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U) {
182 llvm_unreachable("This should never be called because MDNodes have no ops");
185 /// Methods for support type inquiry through isa, cast, and dyn_cast:
186 static inline bool classof(const MDNode *) { return true; }
187 static bool classof(const Value *V) {
188 return V->getValueID() == MDNodeVal;
192 //===----------------------------------------------------------------------===//
193 /// WeakMetadataVH - a weak value handle for metadata.
194 class WeakMetadataVH : public WeakVH {
196 WeakMetadataVH() : WeakVH() {}
197 WeakMetadataVH(MetadataBase *M) : WeakVH(M) {}
198 WeakMetadataVH(const WeakMetadataVH &RHS) : WeakVH(RHS) {}
200 operator Value*() const {
201 llvm_unreachable("WeakMetadataVH only handles Metadata");
204 operator MetadataBase*() const {
205 return dyn_cast_or_null<MetadataBase>(getValPtr());
209 //===----------------------------------------------------------------------===//
210 /// NamedMDNode - a tuple of other metadata.
211 /// NamedMDNode is always named. All NamedMDNode element has a type of metadata.
212 template<typename ValueSubClass, typename ItemParentClass>
213 class SymbolTableListTraits;
215 class NamedMDNode : public MetadataBase, public ilist_node<NamedMDNode> {
216 friend class SymbolTableListTraits<NamedMDNode, Module>;
217 friend class LLVMContextImpl;
219 NamedMDNode(const NamedMDNode &); // DO NOT IMPLEMENT
220 void *operator new(size_t, unsigned); // DO NOT IMPLEMENT
221 // getNumOperands - Make this only available for private uses.
222 unsigned getNumOperands() { return User::getNumOperands(); }
225 SmallVector<WeakMetadataVH, 4> Node;
226 typedef SmallVectorImpl<WeakMetadataVH>::iterator elem_iterator;
229 explicit NamedMDNode(LLVMContext &C, const Twine &N, MetadataBase*const* Vals,
230 unsigned NumVals, Module *M = 0);
232 // Do not allocate any space for operands.
233 void *operator new(size_t s) {
234 return User::operator new(s, 0);
236 static NamedMDNode *Create(LLVMContext &C, const Twine &N,
237 MetadataBase*const*MDs,
238 unsigned NumMDs, Module *M = 0) {
239 return new NamedMDNode(C, N, MDs, NumMDs, M);
242 static NamedMDNode *Create(const NamedMDNode *NMD, Module *M = 0);
244 /// eraseFromParent - Drop all references and remove the node from parent
246 void eraseFromParent();
248 /// dropAllReferences - Remove all uses and clear node vector.
249 void dropAllReferences();
251 /// ~NamedMDNode - Destroy NamedMDNode.
254 /// getParent - Get the module that holds this named metadata collection.
255 inline Module *getParent() { return Parent; }
256 inline const Module *getParent() const { return Parent; }
257 void setParent(Module *M) { Parent = M; }
259 /// getElement - Return specified element.
260 MetadataBase *getElement(unsigned i) const {
261 assert (getNumElements() > i && "Invalid element number!");
265 /// getNumElements - Return number of NamedMDNode elements.
266 unsigned getNumElements() const {
270 /// addElement - Add metadata element.
271 void addElement(MetadataBase *M) {
273 OperandList[NumOperands++] = M;
274 Node.push_back(WeakMetadataVH(M));
277 typedef SmallVectorImpl<WeakMetadataVH>::const_iterator const_elem_iterator;
278 bool elem_empty() const { return Node.empty(); }
279 const_elem_iterator elem_begin() const { return Node.begin(); }
280 const_elem_iterator elem_end() const { return Node.end(); }
281 elem_iterator elem_begin() { return Node.begin(); }
282 elem_iterator elem_end() { return Node.end(); }
284 /// isNullValue - Return true if this is the value that would be returned by
285 /// getNullValue. This always returns false because getNullValue will never
286 /// produce metadata.
287 virtual bool isNullValue() const {
291 virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U) {
293 "This should never be called because NamedMDNodes have no ops");
296 /// Methods for support type inquiry through isa, cast, and dyn_cast:
297 static inline bool classof(const NamedMDNode *) { return true; }
298 static bool classof(const Value *V) {
299 return V->getValueID() == NamedMDNodeVal;
303 } // end llvm namespace