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
23 //===----------------------------------------------------------------------===//
24 /// DSNode - Data structure node class
26 /// This class represents an untyped memory object of Size bytes. It keeps
27 /// track of any pointers that have been stored into the object as well as the
28 /// different types represented in this object.
31 /// NumReferrers - The number of DSNodeHandles pointing to this node... if
32 /// this is a forwarding node, then this is the number of node handles which
33 /// are still forwarding over us.
35 unsigned NumReferrers;
37 /// ForwardNH - This NodeHandle contain the node (and offset into the node)
38 /// that this node really is. When nodes get folded together, the node to be
39 /// eliminated has these fields filled in, otherwise ForwardNH.getNode() is
41 DSNodeHandle ForwardNH;
43 /// Size - The current size of the node. This should be equal to the size of
44 /// the current type record.
48 /// ParentGraph - The graph this node is currently embedded into.
52 /// Ty - Keep track of the current outer most type of this object, in addition
53 /// to whether or not it has been indexed like an array or not. If the
54 /// isArray bit is set, the node cannot grow.
56 const Type *Ty; // The type itself...
58 /// Links - Contains one entry for every sizeof(void*) bytes in this memory
59 /// object. Note that if the node is not a multiple of size(void*) bytes
60 /// large, that there is an extra entry for the "remainder" of the node as
61 /// well. For this reason, nodes of 1 byte in size do have one link.
63 std::vector<DSNodeHandle> Links;
65 /// Globals - The list of global values that are merged into this node.
67 std::vector<GlobalValue*> Globals;
69 void operator=(const DSNode &); // DO NOT IMPLEMENT
70 DSNode(const DSNode &); // DO NOT IMPLEMENT
73 ShadowNode = 0, // Nothing is known about this node...
74 AllocaNode = 1 << 0, // This node was allocated with alloca
75 HeapNode = 1 << 1, // This node was allocated with malloc
76 GlobalNode = 1 << 2, // This node was allocated by a global var decl
77 UnknownNode = 1 << 3, // This node points to unknown allocated memory
78 Incomplete = 1 << 4, // This node may not be complete
80 Modified = 1 << 5, // This node is modified in this context
81 Read = 1 << 6, // This node is read in this context
83 Array = 1 << 7, // This node is treated like an array
85 DEAD = 1 << 8, // This node is dead and should not be pointed to
88 Composition = AllocaNode | HeapNode | GlobalNode | UnknownNode,
91 /// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
92 /// to the nodes in the data structure graph, so it is possible to have nodes
93 /// with a value of 0 for their NodeType.
96 unsigned short NodeType;
99 DSNode(const Type *T, DSGraph *G);
100 DSNode(const DSNode &, DSGraph *G);
104 assert(hasNoReferrers() && "Referrers to dead node exist!");
107 // Iterator for graph interface... Defined in DSGraphTraits.h
108 typedef DSNodeIterator<DSNode> iterator;
109 typedef DSNodeIterator<const DSNode> const_iterator;
110 inline iterator begin();
111 inline iterator end();
112 inline const_iterator begin() const;
113 inline const_iterator end() const;
115 //===--------------------------------------------------
118 /// getSize - Return the maximum number of bytes occupied by this object...
120 unsigned getSize() const { return Size; }
122 // getType - Return the node type of this object...
123 const Type *getType() const { return Ty; }
124 bool isArray() const { return NodeType & Array; }
126 /// hasNoReferrers - Return true if nothing is pointing to this node at all.
128 bool hasNoReferrers() const { return getNumReferrers() == 0; }
130 /// getNumReferrers - This method returns the number of referrers to the
131 /// current node. Note that if this node is a forwarding node, this will
132 /// return the number of nodes forwarding over the node!
133 unsigned getNumReferrers() const { return NumReferrers; }
135 DSGraph *getParentGraph() const { return ParentGraph; }
136 void setParentGraph(DSGraph *G) { ParentGraph = G; }
139 /// getTargetData - Get the target data object used to construct this node.
141 const TargetData &getTargetData() const;
143 /// getForwardNode - This method returns the node that this node is forwarded
145 DSNode *getForwardNode() const { return ForwardNH.getNode(); }
146 void stopForwarding() {
147 assert(!ForwardNH.isNull() &&
148 "Node isn't forwarding, cannot stopForwarding!");
149 ForwardNH.setNode(0);
152 /// hasLink - Return true if this memory object has a link in slot #LinkNo
154 bool hasLink(unsigned Offset) const {
155 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
156 "Pointer offset not aligned correctly!");
157 unsigned Index = Offset >> DS::PointerShift;
158 assert(Index < Links.size() && "Link index is out of range!");
159 return Links[Index].getNode();
162 /// getLink - Return the link at the specified offset.
163 DSNodeHandle &getLink(unsigned Offset) {
164 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
165 "Pointer offset not aligned correctly!");
166 unsigned Index = Offset >> DS::PointerShift;
167 assert(Index < Links.size() && "Link index is out of range!");
170 const DSNodeHandle &getLink(unsigned Offset) const {
171 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
172 "Pointer offset not aligned correctly!");
173 unsigned Index = Offset >> DS::PointerShift;
174 assert(Index < Links.size() && "Link index is out of range!");
178 /// getNumLinks - Return the number of links in a node...
180 unsigned getNumLinks() const { return Links.size(); }
182 /// mergeTypeInfo - This method merges the specified type into the current
183 /// node at the specified offset. This may update the current node's type
184 /// record if this gives more information to the node, it may do nothing to
185 /// the node if this information is already known, or it may merge the node
186 /// completely (and return true) if the information is incompatible with what
187 /// is already known.
189 /// This method returns true if the node is completely folded, otherwise
192 bool mergeTypeInfo(const Type *Ty, unsigned Offset,
193 bool FoldIfIncompatible = true);
195 /// foldNodeCompletely - If we determine that this node has some funny
196 /// behavior happening to it that we cannot represent, we fold it down to a
197 /// single, completely pessimistic, node. This node is represented as a
198 /// single byte with a single TypeEntry of "void" with isArray = true.
200 void foldNodeCompletely();
202 /// isNodeCompletelyFolded - Return true if this node has been completely
203 /// folded down to something that can never be expanded, effectively losing
204 /// all of the field sensitivity that may be present in the node.
206 bool isNodeCompletelyFolded() const;
208 /// setLink - Set the link at the specified offset to the specified
209 /// NodeHandle, replacing what was there. It is uncommon to use this method,
210 /// instead one of the higher level methods should be used, below.
212 void setLink(unsigned Offset, const DSNodeHandle &NH) {
213 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
214 "Pointer offset not aligned correctly!");
215 unsigned Index = Offset >> DS::PointerShift;
216 assert(Index < Links.size() && "Link index is out of range!");
220 /// getPointerSize - Return the size of a pointer for the current target.
222 unsigned getPointerSize() const { return DS::PointerSize; }
224 /// addEdgeTo - Add an edge from the current node to the specified node. This
225 /// can cause merging of nodes in the graph.
227 void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
229 /// mergeWith - Merge this node and the specified node, moving all links to
230 /// and from the argument node into the current node, deleting the node
231 /// argument. Offset indicates what offset the specified node is to be merged
232 /// into the current node.
234 /// The specified node may be a null pointer (in which case, nothing happens).
236 void mergeWith(const DSNodeHandle &NH, unsigned Offset);
238 /// addGlobal - Add an entry for a global value to the Globals list. This
239 /// also marks the node with the 'G' flag if it does not already have it.
241 void addGlobal(GlobalValue *GV);
242 const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
244 /// maskNodeTypes - Apply a mask to the node types bitfield.
246 void maskNodeTypes(unsigned Mask) {
250 /// getNodeFlags - Return all of the flags set on the node. If the DEAD flag
251 /// is set, hide it from the caller.
252 unsigned getNodeFlags() const { return NodeType & ~DEAD; }
254 bool isAllocaNode() const { return NodeType & AllocaNode; }
255 bool isHeapNode() const { return NodeType & HeapNode; }
256 bool isGlobalNode() const { return NodeType & GlobalNode; }
257 bool isUnknownNode() const { return NodeType & UnknownNode; }
259 bool isModified() const { return NodeType & Modified; }
260 bool isRead() const { return NodeType & Read; }
262 bool isIncomplete() const { return NodeType & Incomplete; }
263 bool isComplete() const { return !isIncomplete(); }
264 bool isDeadNode() const { return NodeType & DEAD; }
266 DSNode *setAllocaNodeMarker() { NodeType |= AllocaNode; return this; }
267 DSNode *setHeapNodeMarker() { NodeType |= HeapNode; return this; }
268 DSNode *setGlobalNodeMarker() { NodeType |= GlobalNode; return this; }
269 DSNode *setUnknownNodeMarker() { NodeType |= UnknownNode; return this; }
271 DSNode *setIncompleteMarker() { NodeType |= Incomplete; return this; }
272 DSNode *setModifiedMarker() { NodeType |= Modified; return this; }
273 DSNode *setReadMarker() { NodeType |= Read; return this; }
275 void makeNodeDead() {
277 assert(hasNoReferrers() && "Dead node shouldn't have refs!");
281 /// forwardNode - Mark this node as being obsolete, and all references to it
282 /// should be forwarded to the specified node and offset.
284 void forwardNode(DSNode *To, unsigned Offset);
286 void print(std::ostream &O, const DSGraph *G) const;
289 void assertOK() const;
291 void dropAllReferences() {
293 if (!ForwardNH.isNull())
294 ForwardNH.setNode(0);
297 /// remapLinks - Change all of the Links in the current node according to the
298 /// specified mapping.
299 void remapLinks(hash_map<const DSNode*, DSNodeHandle> &OldNodeMap);
301 /// markReachableNodes - This method recursively traverses the specified
302 /// DSNodes, marking any nodes which are reachable. All reachable nodes it
303 /// adds to the set, which allows it to only traverse visited nodes once.
305 void markReachableNodes(hash_set<DSNode*> &ReachableNodes);
308 friend class DSNodeHandle;
310 // static mergeNodes - Helper for mergeWith()
311 static void MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH);
315 //===----------------------------------------------------------------------===//
316 // Define inline DSNodeHandle functions that depend on the definition of DSNode
318 inline DSNode *DSNodeHandle::getNode() const {
319 assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
320 !N->ForwardNH.isNull()) && "Node handle offset out of range!");
321 if (!N || N->ForwardNH.isNull())
324 return HandleForwarding();
327 inline void DSNodeHandle::setNode(DSNode *n) {
328 assert(!n || !n->getForwardNode() && "Cannot set node to a forwarded node!");
329 if (N) N->NumReferrers--;
333 if (Offset >= N->Size) {
334 assert((Offset == 0 || N->Size == 1) &&
335 "Pointer to non-collapsed node with invalid offset!");
339 assert(!N || ((N->NodeType & DSNode::DEAD) == 0));
340 assert((!N || Offset < N->Size || (N->Size == 0 && Offset == 0) ||
341 !N->ForwardNH.isNull()) && "Node handle offset out of range!");
344 inline bool DSNodeHandle::hasLink(unsigned Num) const {
345 assert(N && "DSNodeHandle does not point to a node yet!");
346 return getNode()->hasLink(Num+Offset);
350 /// getLink - Treat this current node pointer as a pointer to a structure of
351 /// some sort. This method will return the pointer a mem[this+Num]
353 inline const DSNodeHandle &DSNodeHandle::getLink(unsigned Off) const {
354 assert(N && "DSNodeHandle does not point to a node yet!");
355 return getNode()->getLink(Offset+Off);
357 inline DSNodeHandle &DSNodeHandle::getLink(unsigned Off) {
358 assert(N && "DSNodeHandle does not point to a node yet!");
359 return getNode()->getLink(Off+Offset);
362 inline void DSNodeHandle::setLink(unsigned Off, const DSNodeHandle &NH) {
363 assert(N && "DSNodeHandle does not point to a node yet!");
364 getNode()->setLink(Off+Offset, NH);
367 /// addEdgeTo - Add an edge from the current node to the specified node. This
368 /// can cause merging of nodes in the graph.
370 inline void DSNodeHandle::addEdgeTo(unsigned Off, const DSNodeHandle &Node) {
371 assert(N && "DSNodeHandle does not point to a node yet!");
372 getNode()->addEdgeTo(Off+Offset, Node);
375 /// mergeWith - Merge the logical node pointed to by 'this' with the node
376 /// pointed to by 'N'.
378 inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) {
380 getNode()->mergeWith(Node, Offset);
381 else // No node to merge with, so just point to Node