1 //===- DSNode.h - Node definition for datastructure graphs ------*- C++ -*-===//
3 // Data structure graph nodes and some implementation of DSNodeHandle.
5 //===----------------------------------------------------------------------===//
7 #ifndef LLVM_ANALYSIS_DSNODE_H
8 #define LLVM_ANALYSIS_DSNODE_H
12 #include "llvm/Analysis/DSSupport.h"
13 template<typename BaseType>
14 class DSNodeIterator; // Data structure graph traversal iterator
16 //===----------------------------------------------------------------------===//
17 /// DSNode - Data structure node class
19 /// This class represents an untyped memory object of Size bytes. It keeps
20 /// track of any pointers that have been stored into the object as well as the
21 /// different types represented in this object.
24 /// NumReferrers - The number of DSNodeHandles pointing to this node... if
25 /// this is a forwarding node, then this is the number of node handles which
26 /// are still forwarding over us.
28 unsigned NumReferrers;
30 /// ForwardNH - This NodeHandle contain the node (and offset into the node)
31 /// that this node really is. When nodes get folded together, the node to be
32 /// eliminated has these fields filled in, otherwise ForwardNH.getNode() is
34 DSNodeHandle ForwardNH;
36 /// Size - The current size of the node. This should be equal to the size of
37 /// the current type record.
41 /// ParentGraph - The graph this node is currently embedded into.
45 /// Ty - Keep track of the current outer most type of this object, in addition
46 /// to whether or not it has been indexed like an array or not. If the
47 /// isArray bit is set, the node cannot grow.
49 const Type *Ty; // The type itself...
51 /// Links - Contains one entry for every sizeof(void*) bytes in this memory
52 /// object. Note that if the node is not a multiple of size(void*) bytes
53 /// large, that there is an extra entry for the "remainder" of the node as
54 /// well. For this reason, nodes of 1 byte in size do have one link.
56 std::vector<DSNodeHandle> Links;
58 /// Globals - The list of global values that are merged into this node.
60 std::vector<GlobalValue*> Globals;
62 void operator=(const DSNode &); // DO NOT IMPLEMENT
63 DSNode(const DSNode &); // DO NOT IMPLEMENT
66 ShadowNode = 0, // Nothing is known about this node...
67 AllocaNode = 1 << 0, // This node was allocated with alloca
68 HeapNode = 1 << 1, // This node was allocated with malloc
69 GlobalNode = 1 << 2, // This node was allocated by a global var decl
70 UnknownNode = 1 << 3, // This node points to unknown allocated memory
71 Incomplete = 1 << 4, // This node may not be complete
72 Modified = 1 << 5, // This node is modified in this context
73 Read = 1 << 6, // This node is read in this context
74 Array = 1 << 7, // This node is treated like an array
76 DEAD = 1 << 8, // This node is dead and should not be pointed to
79 Composition = AllocaNode | HeapNode | GlobalNode | UnknownNode,
82 /// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
83 /// to the nodes in the data structure graph, so it is possible to have nodes
84 /// with a value of 0 for their NodeType. Scalar and Alloca markers go away
85 /// when function graphs are inlined.
87 unsigned short NodeType;
89 DSNode(unsigned NodeTy, const Type *T, DSGraph *G);
90 DSNode(const DSNode &, DSGraph *G);
94 assert(hasNoReferrers() && "Referrers to dead node exist!");
97 // Iterator for graph interface... Defined in DSGraphTraits.h
98 typedef DSNodeIterator<DSNode> iterator;
99 typedef DSNodeIterator<const DSNode> const_iterator;
100 inline iterator begin();
101 inline iterator end();
102 inline const_iterator begin() const;
103 inline const_iterator end() const;
105 //===--------------------------------------------------
108 /// getSize - Return the maximum number of bytes occupied by this object...
110 unsigned getSize() const { return Size; }
112 // getType - Return the node type of this object...
113 const Type *getType() const { return Ty; }
114 bool isArray() const { return NodeType & Array; }
116 /// hasNoReferrers - Return true if nothing is pointing to this node at all.
118 bool hasNoReferrers() const { return getNumReferrers() == 0; }
120 /// getNumReferrers - This method returns the number of referrers to the
121 /// current node. Note that if this node is a forwarding node, this will
122 /// return the number of nodes forwarding over the node!
123 unsigned getNumReferrers() const { return NumReferrers; }
125 /// isModified - Return true if this node may be modified in this context
127 bool isModified() const { return (NodeType & Modified) != 0; }
129 /// isRead - Return true if this node may be read in this context
131 bool isRead() const { return (NodeType & Read) != 0; }
133 DSGraph *getParentGraph() const { return ParentGraph; }
134 void setParentGraph(DSGraph *G) { ParentGraph = G; }
137 /// getForwardNode - This method returns the node that this node is forwarded
139 DSNode *getForwardNode() const { return ForwardNH.getNode(); }
140 void stopForwarding() {
141 assert(!ForwardNH.isNull() &&
142 "Node isn't forwarding, cannot stopForwarding!");
143 ForwardNH.setNode(0);
146 /// hasLink - Return true if this memory object has a link in slot #LinkNo
148 bool hasLink(unsigned Offset) const {
149 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
150 "Pointer offset not aligned correctly!");
151 unsigned Index = Offset >> DS::PointerShift;
152 assert(Index < Links.size() && "Link index is out of range!");
153 return Links[Index].getNode();
156 /// getLink - Return the link at the specified offset.
157 DSNodeHandle &getLink(unsigned Offset) {
158 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
159 "Pointer offset not aligned correctly!");
160 unsigned Index = Offset >> DS::PointerShift;
161 assert(Index < Links.size() && "Link index is out of range!");
164 const DSNodeHandle &getLink(unsigned Offset) const {
165 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
166 "Pointer offset not aligned correctly!");
167 unsigned Index = Offset >> DS::PointerShift;
168 assert(Index < Links.size() && "Link index is out of range!");
172 /// getNumLinks - Return the number of links in a node...
174 unsigned getNumLinks() const { return Links.size(); }
176 /// mergeTypeInfo - This method merges the specified type into the current
177 /// node at the specified offset. This may update the current node's type
178 /// record if this gives more information to the node, it may do nothing to
179 /// the node if this information is already known, or it may merge the node
180 /// completely (and return true) if the information is incompatible with what
181 /// is already known.
183 /// This method returns true if the node is completely folded, otherwise
186 bool mergeTypeInfo(const Type *Ty, unsigned Offset,
187 bool FoldIfIncompatible = true);
189 /// foldNodeCompletely - If we determine that this node has some funny
190 /// behavior happening to it that we cannot represent, we fold it down to a
191 /// single, completely pessimistic, node. This node is represented as a
192 /// single byte with a single TypeEntry of "void" with isArray = true.
194 void foldNodeCompletely();
196 /// isNodeCompletelyFolded - Return true if this node has been completely
197 /// folded down to something that can never be expanded, effectively losing
198 /// all of the field sensitivity that may be present in the node.
200 bool isNodeCompletelyFolded() const;
202 /// setLink - Set the link at the specified offset to the specified
203 /// NodeHandle, replacing what was there. It is uncommon to use this method,
204 /// instead one of the higher level methods should be used, below.
206 void setLink(unsigned Offset, const DSNodeHandle &NH) {
207 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
208 "Pointer offset not aligned correctly!");
209 unsigned Index = Offset >> DS::PointerShift;
210 assert(Index < Links.size() && "Link index is out of range!");
214 /// getPointerSize - Return the size of a pointer for the current target.
216 unsigned getPointerSize() const { return DS::PointerSize; }
218 /// addEdgeTo - Add an edge from the current node to the specified node. This
219 /// can cause merging of nodes in the graph.
221 void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
223 /// mergeWith - Merge this node and the specified node, moving all links to
224 /// and from the argument node into the current node, deleting the node
225 /// argument. Offset indicates what offset the specified node is to be merged
226 /// into the current node.
228 /// The specified node may be a null pointer (in which case, nothing happens).
230 void mergeWith(const DSNodeHandle &NH, unsigned Offset);
232 /// addGlobal - Add an entry for a global value to the Globals list. This
233 /// also marks the node with the 'G' flag if it does not already have it.
235 void addGlobal(GlobalValue *GV);
236 const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
237 std::vector<GlobalValue*> &getGlobals() { return Globals; }
239 /// forwardNode - Mark this node as being obsolete, and all references to it
240 /// should be forwarded to the specified node and offset.
242 void forwardNode(DSNode *To, unsigned Offset);
244 void print(std::ostream &O, const DSGraph *G) const;
247 void assertOK() const;
249 void dropAllReferences() {
251 if (!ForwardNH.isNull())
252 ForwardNH.setNode(0);
255 /// remapLinks - Change all of the Links in the current node according to the
256 /// specified mapping.
257 void remapLinks(hash_map<const DSNode*, DSNodeHandle> &OldNodeMap);
259 /// markReachableNodes - This method recursively traverses the specified
260 /// DSNodes, marking any nodes which are reachable. All reachable nodes it
261 /// adds to the set, which allows it to only traverse visited nodes once.
263 void markReachableNodes(hash_set<DSNode*> &ReachableNodes);
266 friend class DSNodeHandle;
268 // static mergeNodes - Helper for mergeWith()
269 static void MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH);
273 //===----------------------------------------------------------------------===//
274 // Define inline DSNodeHandle functions that depend on the definition of DSNode
276 inline DSNode *DSNodeHandle::getNode() const {
277 assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
278 !N->ForwardNH.isNull()) && "Node handle offset out of range!");
279 if (!N || N->ForwardNH.isNull())
282 return HandleForwarding();
285 inline void DSNodeHandle::setNode(DSNode *n) {
286 assert(!n || !n->getForwardNode() && "Cannot set node to a forwarded node!");
287 if (N) N->NumReferrers--;
291 if (Offset >= N->Size) {
292 assert((Offset == 0 || N->Size == 1) &&
293 "Pointer to non-collapsed node with invalid offset!");
297 assert(!N || ((N->NodeType & DSNode::DEAD) == 0));
299 assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
300 !N->ForwardNH.isNull()) && "Node handle offset out of range!");
303 inline bool DSNodeHandle::hasLink(unsigned Num) const {
304 assert(N && "DSNodeHandle does not point to a node yet!");
305 return getNode()->hasLink(Num+Offset);
309 /// getLink - Treat this current node pointer as a pointer to a structure of
310 /// some sort. This method will return the pointer a mem[this+Num]
312 inline const DSNodeHandle &DSNodeHandle::getLink(unsigned Off) const {
313 assert(N && "DSNodeHandle does not point to a node yet!");
314 return getNode()->getLink(Offset+Off);
316 inline DSNodeHandle &DSNodeHandle::getLink(unsigned Off) {
317 assert(N && "DSNodeHandle does not point to a node yet!");
318 return getNode()->getLink(Off+Offset);
321 inline void DSNodeHandle::setLink(unsigned Off, const DSNodeHandle &NH) {
322 assert(N && "DSNodeHandle does not point to a node yet!");
323 getNode()->setLink(Off+Offset, NH);
326 /// addEdgeTo - Add an edge from the current node to the specified node. This
327 /// can cause merging of nodes in the graph.
329 inline void DSNodeHandle::addEdgeTo(unsigned Off, const DSNodeHandle &Node) {
330 assert(N && "DSNodeHandle does not point to a node yet!");
331 getNode()->addEdgeTo(Off+Offset, Node);
334 /// mergeWith - Merge the logical node pointed to by 'this' with the node
335 /// pointed to by 'N'.
337 inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) {
339 getNode()->mergeWith(Node, Offset);
340 else // No node to merge with, so just point to Node