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"
19 template<typename BaseType>
20 class DSNodeIterator; // Data structure graph traversal iterator
22 //===----------------------------------------------------------------------===//
23 /// DSNode - Data structure node class
25 /// This class represents an untyped memory object of Size bytes. It keeps
26 /// track of any pointers that have been stored into the object as well as the
27 /// different types represented in this object.
30 /// NumReferrers - The number of DSNodeHandles pointing to this node... if
31 /// this is a forwarding node, then this is the number of node handles which
32 /// are still forwarding over us.
34 unsigned NumReferrers;
36 /// ForwardNH - This NodeHandle contain the node (and offset into the node)
37 /// that this node really is. When nodes get folded together, the node to be
38 /// eliminated has these fields filled in, otherwise ForwardNH.getNode() is
40 DSNodeHandle ForwardNH;
42 /// Size - The current size of the node. This should be equal to the size of
43 /// the current type record.
47 /// ParentGraph - The graph this node is currently embedded into.
51 /// Ty - Keep track of the current outer most type of this object, in addition
52 /// to whether or not it has been indexed like an array or not. If the
53 /// isArray bit is set, the node cannot grow.
55 const Type *Ty; // The type itself...
57 /// Links - Contains one entry for every sizeof(void*) bytes in this memory
58 /// object. Note that if the node is not a multiple of size(void*) bytes
59 /// large, that there is an extra entry for the "remainder" of the node as
60 /// well. For this reason, nodes of 1 byte in size do have one link.
62 std::vector<DSNodeHandle> Links;
64 /// Globals - The list of global values that are merged into this node.
66 std::vector<GlobalValue*> Globals;
68 void operator=(const DSNode &); // DO NOT IMPLEMENT
69 DSNode(const DSNode &); // DO NOT IMPLEMENT
72 ShadowNode = 0, // Nothing is known about this node...
73 AllocaNode = 1 << 0, // This node was allocated with alloca
74 HeapNode = 1 << 1, // This node was allocated with malloc
75 GlobalNode = 1 << 2, // This node was allocated by a global var decl
76 UnknownNode = 1 << 3, // This node points to unknown allocated memory
77 Incomplete = 1 << 4, // This node may not be complete
79 Modified = 1 << 5, // This node is modified in this context
80 Read = 1 << 6, // This node is read in this context
82 Array = 1 << 7, // This node is treated like an array
84 DEAD = 1 << 8, // This node is dead and should not be pointed to
87 Composition = AllocaNode | HeapNode | GlobalNode | UnknownNode,
90 /// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
91 /// to the nodes in the data structure graph, so it is possible to have nodes
92 /// with a value of 0 for their NodeType.
95 unsigned short NodeType;
98 DSNode(const Type *T, DSGraph *G);
99 DSNode(const DSNode &, DSGraph *G);
103 assert(hasNoReferrers() && "Referrers to dead node exist!");
106 // Iterator for graph interface... Defined in DSGraphTraits.h
107 typedef DSNodeIterator<DSNode> iterator;
108 typedef DSNodeIterator<const DSNode> const_iterator;
109 inline iterator begin();
110 inline iterator end();
111 inline const_iterator begin() const;
112 inline const_iterator end() const;
114 //===--------------------------------------------------
117 /// getSize - Return the maximum number of bytes occupied by this object...
119 unsigned getSize() const { return Size; }
121 // getType - Return the node type of this object...
122 const Type *getType() const { return Ty; }
123 bool isArray() const { return NodeType & Array; }
125 /// hasNoReferrers - Return true if nothing is pointing to this node at all.
127 bool hasNoReferrers() const { return getNumReferrers() == 0; }
129 /// getNumReferrers - This method returns the number of referrers to the
130 /// current node. Note that if this node is a forwarding node, this will
131 /// return the number of nodes forwarding over the node!
132 unsigned getNumReferrers() const { return NumReferrers; }
134 DSGraph *getParentGraph() const { return ParentGraph; }
135 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; }
238 /// maskNodeTypes - Apply a mask to the node types bitfield.
240 void maskNodeTypes(unsigned Mask) {
244 /// getNodeFlags - Return all of the flags set on the node. If the DEAD flag
245 /// is set, hide it from the caller.
246 unsigned getNodeFlags() const { return NodeType & ~DEAD; }
248 bool isAllocaNode() const { return NodeType & AllocaNode; }
249 bool isHeapNode() const { return NodeType & HeapNode; }
250 bool isGlobalNode() const { return NodeType & GlobalNode; }
251 bool isUnknownNode() const { return NodeType & UnknownNode; }
253 bool isModified() const { return NodeType & Modified; }
254 bool isRead() const { return NodeType & Read; }
256 bool isIncomplete() const { return NodeType & Incomplete; }
257 bool isComplete() const { return !isIncomplete(); }
258 bool isDeadNode() const { return NodeType & DEAD; }
260 DSNode *setAllocaNodeMarker() { NodeType |= AllocaNode; return this; }
261 DSNode *setHeapNodeMarker() { NodeType |= HeapNode; return this; }
262 DSNode *setGlobalNodeMarker() { NodeType |= GlobalNode; return this; }
263 DSNode *setUnknownNodeMarker() { NodeType |= UnknownNode; return this; }
265 DSNode *setIncompleteMarker() { NodeType |= Incomplete; return this; }
266 DSNode *setModifiedMarker() { NodeType |= Modified; return this; }
267 DSNode *setReadMarker() { NodeType |= Read; return this; }
269 void makeNodeDead() {
271 assert(hasNoReferrers() && "Dead node shouldn't have refs!");
275 /// forwardNode - Mark this node as being obsolete, and all references to it
276 /// should be forwarded to the specified node and offset.
278 void forwardNode(DSNode *To, unsigned Offset);
280 void print(std::ostream &O, const DSGraph *G) const;
283 void assertOK() const;
285 void dropAllReferences() {
287 if (!ForwardNH.isNull())
288 ForwardNH.setNode(0);
291 /// remapLinks - Change all of the Links in the current node according to the
292 /// specified mapping.
293 void remapLinks(hash_map<const DSNode*, DSNodeHandle> &OldNodeMap);
295 /// markReachableNodes - This method recursively traverses the specified
296 /// DSNodes, marking any nodes which are reachable. All reachable nodes it
297 /// adds to the set, which allows it to only traverse visited nodes once.
299 void markReachableNodes(hash_set<DSNode*> &ReachableNodes);
302 friend class DSNodeHandle;
304 // static mergeNodes - Helper for mergeWith()
305 static void MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH);
309 //===----------------------------------------------------------------------===//
310 // Define inline DSNodeHandle functions that depend on the definition of DSNode
312 inline DSNode *DSNodeHandle::getNode() const {
313 assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
314 !N->ForwardNH.isNull()) && "Node handle offset out of range!");
315 if (!N || N->ForwardNH.isNull())
318 return HandleForwarding();
321 inline void DSNodeHandle::setNode(DSNode *n) {
322 assert(!n || !n->getForwardNode() && "Cannot set node to a forwarded node!");
323 if (N) N->NumReferrers--;
327 if (Offset >= N->Size) {
328 assert((Offset == 0 || N->Size == 1) &&
329 "Pointer to non-collapsed node with invalid offset!");
333 assert(!N || ((N->NodeType & DSNode::DEAD) == 0));
334 assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
335 !N->ForwardNH.isNull()) && "Node handle offset out of range!");
338 inline bool DSNodeHandle::hasLink(unsigned Num) const {
339 assert(N && "DSNodeHandle does not point to a node yet!");
340 return getNode()->hasLink(Num+Offset);
344 /// getLink - Treat this current node pointer as a pointer to a structure of
345 /// some sort. This method will return the pointer a mem[this+Num]
347 inline const DSNodeHandle &DSNodeHandle::getLink(unsigned Off) const {
348 assert(N && "DSNodeHandle does not point to a node yet!");
349 return getNode()->getLink(Offset+Off);
351 inline DSNodeHandle &DSNodeHandle::getLink(unsigned Off) {
352 assert(N && "DSNodeHandle does not point to a node yet!");
353 return getNode()->getLink(Off+Offset);
356 inline void DSNodeHandle::setLink(unsigned Off, const DSNodeHandle &NH) {
357 assert(N && "DSNodeHandle does not point to a node yet!");
358 getNode()->setLink(Off+Offset, NH);
361 /// addEdgeTo - Add an edge from the current node to the specified node. This
362 /// can cause merging of nodes in the graph.
364 inline void DSNodeHandle::addEdgeTo(unsigned Off, const DSNodeHandle &Node) {
365 assert(N && "DSNodeHandle does not point to a node yet!");
366 getNode()->addEdgeTo(Off+Offset, Node);
369 /// mergeWith - Merge the logical node pointed to by 'this' with the node
370 /// pointed to by 'N'.
372 inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) {
374 getNode()->mergeWith(Node, Offset);
375 else // No node to merge with, so just point to Node