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/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
43 DSNodeHandle ForwardNH;
45 /// Size - The current size of the node. This should be equal to the size of
46 /// the current type record.
50 /// ParentGraph - The graph this node is currently embedded into.
54 /// Ty - Keep track of the current outer most type of this object, in addition
55 /// to whether or not it has been indexed like an array or not. If the
56 /// isArray bit is set, the node cannot grow.
58 const Type *Ty; // The type itself...
60 /// Links - Contains one entry for every sizeof(void*) bytes in this memory
61 /// object. Note that if the node is not a multiple of size(void*) bytes
62 /// large, that there is an extra entry for the "remainder" of the node as
63 /// well. For this reason, nodes of 1 byte in size do have one link.
65 std::vector<DSNodeHandle> Links;
67 /// Globals - The list of global values that are merged into this node.
69 std::vector<GlobalValue*> Globals;
71 void operator=(const DSNode &); // DO NOT IMPLEMENT
72 DSNode(const DSNode &); // DO NOT IMPLEMENT
75 ShadowNode = 0, // Nothing is known about this node...
76 AllocaNode = 1 << 0, // This node was allocated with alloca
77 HeapNode = 1 << 1, // This node was allocated with malloc
78 GlobalNode = 1 << 2, // This node was allocated by a global var decl
79 UnknownNode = 1 << 3, // This node points to unknown allocated memory
80 Incomplete = 1 << 4, // This node may not be complete
82 Modified = 1 << 5, // This node is modified in this context
83 Read = 1 << 6, // This node is read in this context
85 Array = 1 << 7, // This node is treated like an array
87 DEAD = 1 << 8, // This node is dead and should not be pointed to
90 Composition = AllocaNode | HeapNode | GlobalNode | UnknownNode,
93 /// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
94 /// to the nodes in the data structure graph, so it is possible to have nodes
95 /// with a value of 0 for their NodeType.
98 unsigned short NodeType;
101 /// DSNode ctor - Create a node of the specified type, inserting it into the
103 DSNode(const Type *T, DSGraph *G);
105 /// DSNode "copy ctor" - Copy the specified node, inserting it into the
106 /// specified graph. If NullLinks is true, then null out all of the links,
107 /// but keep the same number of them. This can be used for efficiency if the
108 /// links are just going to be clobbered anyway.
109 DSNode(const DSNode &, DSGraph *G, bool NullLinks = false);
113 assert(hasNoReferrers() && "Referrers to dead node exist!");
116 // Iterator for graph interface... Defined in DSGraphTraits.h
117 typedef DSNodeIterator<DSNode> iterator;
118 typedef DSNodeIterator<const DSNode> const_iterator;
119 inline iterator begin();
120 inline iterator end();
121 inline const_iterator begin() const;
122 inline const_iterator end() const;
124 //===--------------------------------------------------
127 /// getSize - Return the maximum number of bytes occupied by this object...
129 unsigned getSize() const { return Size; }
131 // getType - Return the node type of this object...
132 const Type *getType() const { return Ty; }
133 bool isArray() const { return NodeType & Array; }
135 /// hasNoReferrers - Return true if nothing is pointing to this node at all.
137 bool hasNoReferrers() const { return getNumReferrers() == 0; }
139 /// getNumReferrers - This method returns the number of referrers to the
140 /// current node. Note that if this node is a forwarding node, this will
141 /// return the number of nodes forwarding over the node!
142 unsigned getNumReferrers() const { return NumReferrers; }
144 DSGraph *getParentGraph() const { return ParentGraph; }
145 void setParentGraph(DSGraph *G) { ParentGraph = G; }
148 /// getTargetData - Get the target data object used to construct this node.
150 const TargetData &getTargetData() const;
152 /// getForwardNode - This method returns the node that this node is forwarded
154 DSNode *getForwardNode() const { return ForwardNH.getNode(); }
156 /// isForwarding - Return true if this node is forwarding to another.
157 bool isForwarding() const { return !ForwardNH.isNull(); }
159 void stopForwarding() {
160 assert(isForwarding() &&
161 "Node isn't forwarding, cannot stopForwarding!");
162 ForwardNH.setNode(0);
165 /// hasLink - Return true if this memory object has a link in slot #LinkNo
167 bool hasLink(unsigned Offset) const {
168 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
169 "Pointer offset not aligned correctly!");
170 unsigned Index = Offset >> DS::PointerShift;
171 assert(Index < Links.size() && "Link index is out of range!");
172 return Links[Index].getNode();
175 /// getLink - Return the link at the specified offset.
176 DSNodeHandle &getLink(unsigned Offset) {
177 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
178 "Pointer offset not aligned correctly!");
179 unsigned Index = Offset >> DS::PointerShift;
180 assert(Index < Links.size() && "Link index is out of range!");
183 const DSNodeHandle &getLink(unsigned Offset) const {
184 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
185 "Pointer offset not aligned correctly!");
186 unsigned Index = Offset >> DS::PointerShift;
187 assert(Index < Links.size() && "Link index is out of range!");
191 /// getNumLinks - Return the number of links in a node...
193 unsigned getNumLinks() const { return Links.size(); }
195 /// mergeTypeInfo - This method merges the specified type into the current
196 /// node at the specified offset. This may update the current node's type
197 /// record if this gives more information to the node, it may do nothing to
198 /// the node if this information is already known, or it may merge the node
199 /// completely (and return true) if the information is incompatible with what
200 /// is already known.
202 /// This method returns true if the node is completely folded, otherwise
205 bool mergeTypeInfo(const Type *Ty, unsigned Offset,
206 bool FoldIfIncompatible = true);
208 /// foldNodeCompletely - If we determine that this node has some funny
209 /// behavior happening to it that we cannot represent, we fold it down to a
210 /// single, completely pessimistic, node. This node is represented as a
211 /// single byte with a single TypeEntry of "void" with isArray = true.
213 void foldNodeCompletely();
215 /// isNodeCompletelyFolded - Return true if this node has been completely
216 /// folded down to something that can never be expanded, effectively losing
217 /// all of the field sensitivity that may be present in the node.
219 bool isNodeCompletelyFolded() const;
221 /// setLink - Set the link at the specified offset to the specified
222 /// NodeHandle, replacing what was there. It is uncommon to use this method,
223 /// instead one of the higher level methods should be used, below.
225 void setLink(unsigned Offset, const DSNodeHandle &NH) {
226 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
227 "Pointer offset not aligned correctly!");
228 unsigned Index = Offset >> DS::PointerShift;
229 assert(Index < Links.size() && "Link index is out of range!");
233 /// getPointerSize - Return the size of a pointer for the current target.
235 unsigned getPointerSize() const { return DS::PointerSize; }
237 /// addEdgeTo - Add an edge from the current node to the specified node. This
238 /// can cause merging of nodes in the graph.
240 void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
242 /// mergeWith - Merge this node and the specified node, moving all links to
243 /// and from the argument node into the current node, deleting the node
244 /// argument. Offset indicates what offset the specified node is to be merged
245 /// into the current node.
247 /// The specified node may be a null pointer (in which case, nothing happens).
249 void mergeWith(const DSNodeHandle &NH, unsigned Offset);
251 /// addGlobal - Add an entry for a global value to the Globals list. This
252 /// also marks the node with the 'G' flag if it does not already have it.
254 void addGlobal(GlobalValue *GV);
255 void mergeGlobals(const std::vector<GlobalValue*> &RHS);
256 const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
258 typedef std::vector<GlobalValue*>::const_iterator global_iterator;
259 global_iterator global_begin() const { return Globals.begin(); }
260 global_iterator global_end() const { return Globals.end(); }
263 /// maskNodeTypes - Apply a mask to the node types bitfield.
265 void maskNodeTypes(unsigned Mask) {
269 void mergeNodeFlags(unsigned RHS) {
273 /// getNodeFlags - Return all of the flags set on the node. If the DEAD flag
274 /// is set, hide it from the caller.
275 unsigned getNodeFlags() const { return NodeType & ~DEAD; }
277 bool isAllocaNode() const { return NodeType & AllocaNode; }
278 bool isHeapNode() const { return NodeType & HeapNode; }
279 bool isGlobalNode() const { return NodeType & GlobalNode; }
280 bool isUnknownNode() const { return NodeType & UnknownNode; }
282 bool isModified() const { return NodeType & Modified; }
283 bool isRead() const { return NodeType & Read; }
285 bool isIncomplete() const { return NodeType & Incomplete; }
286 bool isComplete() const { return !isIncomplete(); }
287 bool isDeadNode() const { return NodeType & DEAD; }
289 DSNode *setAllocaNodeMarker() { NodeType |= AllocaNode; return this; }
290 DSNode *setHeapNodeMarker() { NodeType |= HeapNode; return this; }
291 DSNode *setGlobalNodeMarker() { NodeType |= GlobalNode; return this; }
292 DSNode *setUnknownNodeMarker() { NodeType |= UnknownNode; return this; }
294 DSNode *setIncompleteMarker() { NodeType |= Incomplete; return this; }
295 DSNode *setModifiedMarker() { NodeType |= Modified; return this; }
296 DSNode *setReadMarker() { NodeType |= Read; return this; }
298 void makeNodeDead() {
300 assert(hasNoReferrers() && "Dead node shouldn't have refs!");
304 /// forwardNode - Mark this node as being obsolete, and all references to it
305 /// should be forwarded to the specified node and offset.
307 void forwardNode(DSNode *To, unsigned Offset);
309 void print(std::ostream &O, const DSGraph *G) const;
312 void assertOK() const;
314 void dropAllReferences() {
317 ForwardNH.setNode(0);
320 /// remapLinks - Change all of the Links in the current node according to the
321 /// specified mapping.
322 void remapLinks(hash_map<const DSNode*, DSNodeHandle> &OldNodeMap);
324 /// markReachableNodes - This method recursively traverses the specified
325 /// DSNodes, marking any nodes which are reachable. All reachable nodes it
326 /// adds to the set, which allows it to only traverse visited nodes once.
328 void markReachableNodes(hash_set<DSNode*> &ReachableNodes);
331 friend class DSNodeHandle;
333 // static mergeNodes - Helper for mergeWith()
334 static void MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH);
338 //===----------------------------------------------------------------------===//
339 // Define inline DSNodeHandle functions that depend on the definition of DSNode
341 inline DSNode *DSNodeHandle::getNode() const {
342 assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
343 N->isForwarding()) && "Node handle offset out of range!");
344 if (N == 0 || !N->isForwarding())
347 return HandleForwarding();
350 inline void DSNodeHandle::setNode(DSNode *n) const {
351 assert(!n || !n->getForwardNode() && "Cannot set node to a forwarded node!");
352 if (N) N->NumReferrers--;
356 if (Offset >= N->Size) {
357 assert((Offset == 0 || N->Size == 1) &&
358 "Pointer to non-collapsed node with invalid offset!");
362 assert(!N || ((N->NodeType & DSNode::DEAD) == 0));
363 assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
364 N->isForwarding()) && "Node handle offset out of range!");
367 inline bool DSNodeHandle::hasLink(unsigned Num) const {
368 assert(N && "DSNodeHandle does not point to a node yet!");
369 return getNode()->hasLink(Num+Offset);
373 /// getLink - Treat this current node pointer as a pointer to a structure of
374 /// some sort. This method will return the pointer a mem[this+Num]
376 inline const DSNodeHandle &DSNodeHandle::getLink(unsigned Off) const {
377 assert(N && "DSNodeHandle does not point to a node yet!");
378 return getNode()->getLink(Offset+Off);
380 inline DSNodeHandle &DSNodeHandle::getLink(unsigned Off) {
381 assert(N && "DSNodeHandle does not point to a node yet!");
382 return getNode()->getLink(Off+Offset);
385 inline void DSNodeHandle::setLink(unsigned Off, const DSNodeHandle &NH) {
386 assert(N && "DSNodeHandle does not point to a node yet!");
387 getNode()->setLink(Off+Offset, NH);
390 /// addEdgeTo - Add an edge from the current node to the specified node. This
391 /// can cause merging of nodes in the graph.
393 inline void DSNodeHandle::addEdgeTo(unsigned Off, const DSNodeHandle &Node) {
394 assert(N && "DSNodeHandle does not point to a node yet!");
395 getNode()->addEdgeTo(Off+Offset, Node);
398 /// mergeWith - Merge the logical node pointed to by 'this' with the node
399 /// pointed to by 'N'.
401 inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) const {
403 getNode()->mergeWith(Node, Offset);
404 else { // No node to merge with, so just point to Node
406 setNode(Node.getNode());
407 Offset = Node.getOffset();
411 } // End llvm namespace