1 //===- DSNode.h - Node definition for datastructure graphs ------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Data structure graph nodes and some implementation of DSNodeHandle.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ANALYSIS_DSNODE_H
15 #define LLVM_ANALYSIS_DSNODE_H
17 #include "llvm/Analysis/DataStructure/DSSupport.h"
21 template<typename BaseType>
22 class DSNodeIterator; // Data structure graph traversal iterator
25 //===----------------------------------------------------------------------===//
26 /// DSNode - Data structure node class
28 /// This class represents an untyped memory object of Size bytes. It keeps
29 /// track of any pointers that have been stored into the object as well as the
30 /// different types represented in this object.
33 /// NumReferrers - The number of DSNodeHandles pointing to this node... if
34 /// this is a forwarding node, then this is the number of node handles which
35 /// are still forwarding over us.
37 unsigned NumReferrers;
39 /// ForwardNH - This NodeHandle contain the node (and offset into the node)
40 /// that this node really is. When nodes get folded together, the node to be
41 /// eliminated has these fields filled in, otherwise ForwardNH.getNode() is
44 DSNodeHandle ForwardNH;
46 /// Next, Prev - These instance variables are used to keep the node on a
47 /// doubly-linked ilist in the DSGraph.
50 friend class ilist_traits<DSNode>;
52 /// Size - The current size of the node. This should be equal to the size of
53 /// the current type record.
57 /// ParentGraph - The graph this node is currently embedded into.
61 /// Ty - Keep track of the current outer most type of this object, in addition
62 /// to whether or not it has been indexed like an array or not. If the
63 /// isArray bit is set, the node cannot grow.
65 const Type *Ty; // The type itself...
67 /// Links - Contains one entry for every sizeof(void*) bytes in this memory
68 /// object. Note that if the node is not a multiple of size(void*) bytes
69 /// large, that there is an extra entry for the "remainder" of the node as
70 /// well. For this reason, nodes of 1 byte in size do have one link.
72 std::vector<DSNodeHandle> Links;
74 /// Globals - The list of global values that are merged into this node.
76 std::vector<GlobalValue*> Globals;
78 void operator=(const DSNode &); // DO NOT IMPLEMENT
79 DSNode(const DSNode &); // DO NOT IMPLEMENT
82 ShadowNode = 0, // Nothing is known about this node...
83 AllocaNode = 1 << 0, // This node was allocated with alloca
84 HeapNode = 1 << 1, // This node was allocated with malloc
85 GlobalNode = 1 << 2, // This node was allocated by a global var decl
86 UnknownNode = 1 << 3, // This node points to unknown allocated memory
87 Incomplete = 1 << 4, // This node may not be complete
89 Modified = 1 << 5, // This node is modified in this context
90 Read = 1 << 6, // This node is read in this context
92 Array = 1 << 7, // This node is treated like an array
94 DEAD = 1 << 8, // This node is dead and should not be pointed to
97 Composition = AllocaNode | HeapNode | GlobalNode | UnknownNode,
100 /// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
101 /// to the nodes in the data structure graph, so it is possible to have nodes
102 /// with a value of 0 for their NodeType.
105 unsigned short NodeType;
108 /// DSNode ctor - Create a node of the specified type, inserting it into the
111 DSNode(const Type *T, DSGraph *G);
113 /// DSNode "copy ctor" - Copy the specified node, inserting it into the
114 /// specified graph. If NullLinks is true, then null out all of the links,
115 /// but keep the same number of them. This can be used for efficiency if the
116 /// links are just going to be clobbered anyway.
118 DSNode(const DSNode &, DSGraph *G, bool NullLinks = false);
122 assert(hasNoReferrers() && "Referrers to dead node exist!");
125 // Iterator for graph interface... Defined in DSGraphTraits.h
126 typedef DSNodeIterator<DSNode> iterator;
127 typedef DSNodeIterator<const DSNode> const_iterator;
128 inline iterator begin();
129 inline iterator end();
130 inline const_iterator begin() const;
131 inline const_iterator end() const;
133 //===--------------------------------------------------
136 /// getSize - Return the maximum number of bytes occupied by this object...
138 unsigned getSize() const { return Size; }
140 /// getType - Return the node type of this object...
142 const Type *getType() const { return Ty; }
144 bool isArray() const { return NodeType & Array; }
146 /// hasNoReferrers - Return true if nothing is pointing to this node at all.
148 bool hasNoReferrers() const { return getNumReferrers() == 0; }
150 /// getNumReferrers - This method returns the number of referrers to the
151 /// current node. Note that if this node is a forwarding node, this will
152 /// return the number of nodes forwarding over the node!
153 unsigned getNumReferrers() const { return NumReferrers; }
155 DSGraph *getParentGraph() const { return ParentGraph; }
156 void setParentGraph(DSGraph *G) { ParentGraph = G; }
159 /// getTargetData - Get the target data object used to construct this node.
161 const TargetData &getTargetData() const;
163 /// getForwardNode - This method returns the node that this node is forwarded
166 DSNode *getForwardNode() const { return ForwardNH.getNode(); }
168 /// isForwarding - Return true if this node is forwarding to another.
170 bool isForwarding() const { return !ForwardNH.isNull(); }
172 /// stopForwarding - When the last reference to this forwarding node has been
173 /// dropped, delete the node.
175 void stopForwarding() {
176 assert(isForwarding() &&
177 "Node isn't forwarding, cannot stopForwarding()!");
178 ForwardNH.setTo(0, 0);
179 assert(ParentGraph == 0 &&
180 "Forwarding nodes must have been removed from graph!");
184 /// hasLink - Return true if this memory object has a link in slot #LinkNo
186 bool hasLink(unsigned Offset) const {
187 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
188 "Pointer offset not aligned correctly!");
189 unsigned Index = Offset >> DS::PointerShift;
190 assert(Index < Links.size() && "Link index is out of range!");
191 return Links[Index].getNode();
194 /// getLink - Return the link at the specified offset.
196 DSNodeHandle &getLink(unsigned Offset) {
197 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
198 "Pointer offset not aligned correctly!");
199 unsigned Index = Offset >> DS::PointerShift;
200 assert(Index < Links.size() && "Link index is out of range!");
203 const DSNodeHandle &getLink(unsigned Offset) const {
204 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
205 "Pointer offset not aligned correctly!");
206 unsigned Index = Offset >> DS::PointerShift;
207 assert(Index < Links.size() && "Link index is out of range!");
211 /// getNumLinks - Return the number of links in a node...
213 unsigned getNumLinks() const { return Links.size(); }
215 /// mergeTypeInfo - This method merges the specified type into the current
216 /// node at the specified offset. This may update the current node's type
217 /// record if this gives more information to the node, it may do nothing to
218 /// the node if this information is already known, or it may merge the node
219 /// completely (and return true) if the information is incompatible with what
220 /// is already known.
222 /// This method returns true if the node is completely folded, otherwise
225 bool mergeTypeInfo(const Type *Ty, unsigned Offset,
226 bool FoldIfIncompatible = true);
228 /// foldNodeCompletely - If we determine that this node has some funny
229 /// behavior happening to it that we cannot represent, we fold it down to a
230 /// single, completely pessimistic, node. This node is represented as a
231 /// single byte with a single TypeEntry of "void" with isArray = true.
233 void foldNodeCompletely();
235 /// isNodeCompletelyFolded - Return true if this node has been completely
236 /// folded down to something that can never be expanded, effectively losing
237 /// all of the field sensitivity that may be present in the node.
239 bool isNodeCompletelyFolded() const;
241 /// setLink - Set the link at the specified offset to the specified
242 /// NodeHandle, replacing what was there. It is uncommon to use this method,
243 /// instead one of the higher level methods should be used, below.
245 void setLink(unsigned Offset, const DSNodeHandle &NH) {
246 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
247 "Pointer offset not aligned correctly!");
248 unsigned Index = Offset >> DS::PointerShift;
249 assert(Index < Links.size() && "Link index is out of range!");
253 /// getPointerSize - Return the size of a pointer for the current target.
255 unsigned getPointerSize() const { return DS::PointerSize; }
257 /// addEdgeTo - Add an edge from the current node to the specified node. This
258 /// can cause merging of nodes in the graph.
260 void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
262 /// mergeWith - Merge this node and the specified node, moving all links to
263 /// and from the argument node into the current node, deleting the node
264 /// argument. Offset indicates what offset the specified node is to be merged
265 /// into the current node.
267 /// The specified node may be a null pointer (in which case, nothing happens).
269 void mergeWith(const DSNodeHandle &NH, unsigned Offset);
271 /// addGlobal - Add an entry for a global value to the Globals list. This
272 /// also marks the node with the 'G' flag if it does not already have it.
274 void addGlobal(GlobalValue *GV);
275 void mergeGlobals(const std::vector<GlobalValue*> &RHS);
276 const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
278 typedef std::vector<GlobalValue*>::const_iterator global_iterator;
279 global_iterator global_begin() const { return Globals.begin(); }
280 global_iterator global_end() const { return Globals.end(); }
283 /// maskNodeTypes - Apply a mask to the node types bitfield.
285 void maskNodeTypes(unsigned Mask) {
289 void mergeNodeFlags(unsigned RHS) {
293 /// getNodeFlags - Return all of the flags set on the node. If the DEAD flag
294 /// is set, hide it from the caller.
296 unsigned getNodeFlags() const { return NodeType & ~DEAD; }
298 bool isAllocaNode() const { return NodeType & AllocaNode; }
299 bool isHeapNode() const { return NodeType & HeapNode; }
300 bool isGlobalNode() const { return NodeType & GlobalNode; }
301 bool isUnknownNode() const { return NodeType & UnknownNode; }
303 bool isModified() const { return NodeType & Modified; }
304 bool isRead() const { return NodeType & Read; }
306 bool isIncomplete() const { return NodeType & Incomplete; }
307 bool isComplete() const { return !isIncomplete(); }
308 bool isDeadNode() const { return NodeType & DEAD; }
310 DSNode *setAllocaNodeMarker() { NodeType |= AllocaNode; return this; }
311 DSNode *setHeapNodeMarker() { NodeType |= HeapNode; return this; }
312 DSNode *setGlobalNodeMarker() { NodeType |= GlobalNode; return this; }
313 DSNode *setUnknownNodeMarker() { NodeType |= UnknownNode; return this; }
315 DSNode *setIncompleteMarker() { NodeType |= Incomplete; return this; }
316 DSNode *setModifiedMarker() { NodeType |= Modified; return this; }
317 DSNode *setReadMarker() { NodeType |= Read; return this; }
318 DSNode *setArrayMarker() { NodeType |= Array; return this; }
320 void makeNodeDead() {
322 assert(hasNoReferrers() && "Dead node shouldn't have refs!");
326 /// forwardNode - Mark this node as being obsolete, and all references to it
327 /// should be forwarded to the specified node and offset.
329 void forwardNode(DSNode *To, unsigned Offset);
331 void print(std::ostream &O, const DSGraph *G) const;
334 void assertOK() const;
336 void dropAllReferences() {
339 ForwardNH.setTo(0, 0);
342 /// remapLinks - Change all of the Links in the current node according to the
343 /// specified mapping.
345 void remapLinks(hash_map<const DSNode*, DSNodeHandle> &OldNodeMap);
347 /// markReachableNodes - This method recursively traverses the specified
348 /// DSNodes, marking any nodes which are reachable. All reachable nodes it
349 /// adds to the set, which allows it to only traverse visited nodes once.
351 void markReachableNodes(hash_set<DSNode*> &ReachableNodes);
354 friend class DSNodeHandle;
356 // static mergeNodes - Helper for mergeWith()
357 static void MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH);
360 //===----------------------------------------------------------------------===//
361 // Define the ilist_traits specialization for the DSGraph ilist.
364 struct ilist_traits<DSNode> {
365 static DSNode *getPrev(const DSNode *N) { return N->Prev; }
366 static DSNode *getNext(const DSNode *N) { return N->Next; }
368 static void setPrev(DSNode *N, DSNode *Prev) { N->Prev = Prev; }
369 static void setNext(DSNode *N, DSNode *Next) { N->Next = Next; }
371 static DSNode *createNode() { return new DSNode(0,0); }
372 //static DSNode *createNode(const DSNode &V) { return new DSNode(V); }
375 void addNodeToList(DSNode *NTy) {}
376 void removeNodeFromList(DSNode *NTy) {}
377 void transferNodesFromList(iplist<DSNode, ilist_traits> &L2,
378 ilist_iterator<DSNode> first,
379 ilist_iterator<DSNode> last) {}
383 struct ilist_traits<const DSNode> : public ilist_traits<DSNode> {};
385 //===----------------------------------------------------------------------===//
386 // Define inline DSNodeHandle functions that depend on the definition of DSNode
388 inline DSNode *DSNodeHandle::getNode() const {
389 // Disabling this assertion because it is failing on a "magic" struct
390 // in named (from bind). The fourth field is an array of length 0,
391 // presumably used to create struct instances of different sizes.
393 N->isNodeCompletelyFolded() ||
394 (N->Size == 0 && Offset == 0) ||
395 (int(Offset) >= 0 && Offset < N->Size) ||
396 (int(Offset) < 0 && -int(Offset) < int(N->Size)) ||
397 N->isForwarding()) && "Node handle offset out of range!");
398 if (N == 0 || !N->isForwarding())
401 return HandleForwarding();
404 inline void DSNodeHandle::setTo(DSNode *n, unsigned NewOffset) const {
405 assert(!n || !n->isForwarding() && "Cannot set node to a forwarded node!");
406 if (N) getNode()->NumReferrers--;
411 if (Offset >= N->Size) {
412 assert((Offset == 0 || N->Size == 1) &&
413 "Pointer to non-collapsed node with invalid offset!");
417 assert(!N || ((N->NodeType & DSNode::DEAD) == 0));
418 assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
419 N->isForwarding()) && "Node handle offset out of range!");
422 inline bool DSNodeHandle::hasLink(unsigned Num) const {
423 assert(N && "DSNodeHandle does not point to a node yet!");
424 return getNode()->hasLink(Num+Offset);
428 /// getLink - Treat this current node pointer as a pointer to a structure of
429 /// some sort. This method will return the pointer a mem[this+Num]
431 inline const DSNodeHandle &DSNodeHandle::getLink(unsigned Off) const {
432 assert(N && "DSNodeHandle does not point to a node yet!");
433 return getNode()->getLink(Offset+Off);
435 inline DSNodeHandle &DSNodeHandle::getLink(unsigned Off) {
436 assert(N && "DSNodeHandle does not point to a node yet!");
437 return getNode()->getLink(Off+Offset);
440 inline void DSNodeHandle::setLink(unsigned Off, const DSNodeHandle &NH) {
441 assert(N && "DSNodeHandle does not point to a node yet!");
442 getNode()->setLink(Off+Offset, NH);
445 /// addEdgeTo - Add an edge from the current node to the specified node. This
446 /// can cause merging of nodes in the graph.
448 inline void DSNodeHandle::addEdgeTo(unsigned Off, const DSNodeHandle &Node) {
449 assert(N && "DSNodeHandle does not point to a node yet!");
450 getNode()->addEdgeTo(Off+Offset, Node);
453 /// mergeWith - Merge the logical node pointed to by 'this' with the node
454 /// pointed to by 'N'.
456 inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) const {
458 getNode()->mergeWith(Node, Offset);
459 else { // No node to merge with, so just point to Node
461 DSNode *NN = Node.getNode();
462 setTo(NN, Node.getOffset());
466 } // End llvm namespace