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
10 #include "llvm/Analysis/DSSupport.h"
12 //===----------------------------------------------------------------------===//
13 /// DSNode - Data structure node class
15 /// This class represents an untyped memory object of Size bytes. It keeps
16 /// track of any pointers that have been stored into the object as well as the
17 /// different types represented in this object.
20 /// Referrers - Keep track of all of the node handles that point to this
21 /// DSNode. These pointers may need to be updated to point to a different
22 /// node if this node gets merged with it.
24 std::vector<DSNodeHandle*> Referrers;
26 /// Links - Contains one entry for every sizeof(void*) bytes in this memory
27 /// object. Note that if the node is not a multiple of size(void*) bytes
28 /// large, that there is an extra entry for the "remainder" of the node as
29 /// well. For this reason, nodes of 1 byte in size do have one link.
31 std::vector<DSNodeHandle> Links;
33 /// Globals - The list of global values that are merged into this node.
35 std::vector<GlobalValue*> Globals;
37 /// Type - Keep track of the current outer most type of this object, in
38 /// addition to whether or not it has been indexed like an array or not. If
39 /// the isArray bit is set, the node cannot grow.
43 /// Size - The current size of the node. This should be equal to the size of
44 /// the current type record.
48 void operator=(const DSNode &); // DO NOT IMPLEMENT
51 ShadowNode = 0, // Nothing is known about this node...
52 AllocaNode = 1 << 0, // This node was allocated with alloca
53 HeapNode = 1 << 1, // This node was allocated with malloc
54 GlobalNode = 1 << 2, // This node was allocated by a global var decl
55 UnknownNode = 1 << 3, // This node points to unknown allocated memory
56 Incomplete = 1 << 4, // This node may not be complete
57 Modified = 1 << 5, // This node is modified in this context
58 Read = 1 << 6, // This node is read in this context
60 DEAD = 1 << 7, // This node is dead and should not be pointed to
64 /// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
65 /// to the nodes in the data structure graph, so it is possible to have nodes
66 /// with a value of 0 for their NodeType. Scalar and Alloca markers go away
67 /// when function graphs are inlined.
69 unsigned char NodeType;
71 DSNode(enum NodeTy NT, const Type *T);
72 DSNode(const DSNode &);
76 assert(Referrers.empty() && "Referrers to dead node exist!");
79 // Iterator for graph interface...
80 typedef DSNodeIterator iterator;
81 typedef DSNodeIterator const_iterator;
82 inline iterator begin() const; // Defined in DSGraphTraits.h
83 inline iterator end() const;
85 //===--------------------------------------------------
88 /// getSize - Return the maximum number of bytes occupied by this object...
90 unsigned getSize() const { return Size; }
92 // getType - Return the node type of this object...
93 const DSTypeRec &getType() const { return Ty; }
95 /// getReferrers - Return a list of the pointers to this node...
97 const std::vector<DSNodeHandle*> &getReferrers() const { return Referrers; }
99 /// hasNoReferrers - Return true if nothing is pointing to this node at all.
101 bool hasNoReferrers() const { return Referrers.empty(); }
103 /// isModified - Return true if this node may be modified in this context
105 bool isModified() const { return (NodeType & Modified) != 0; }
107 /// isRead - Return true if this node may be read in this context
109 bool isRead() const { return (NodeType & Read) != 0; }
112 /// hasLink - Return true if this memory object has a link in slot #LinkNo
114 bool hasLink(unsigned Offset) const {
115 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
116 "Pointer offset not aligned correctly!");
117 unsigned Index = Offset >> DS::PointerShift;
118 assert(Index < Links.size() && "Link index is out of range!");
119 return Links[Index].getNode();
122 /// getLink - Return the link at the specified offset.
123 DSNodeHandle &getLink(unsigned Offset) {
124 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
125 "Pointer offset not aligned correctly!");
126 unsigned Index = Offset >> DS::PointerShift;
127 assert(Index < Links.size() && "Link index is out of range!");
130 const DSNodeHandle &getLink(unsigned Offset) const {
131 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
132 "Pointer offset not aligned correctly!");
133 unsigned Index = Offset >> DS::PointerShift;
134 assert(Index < Links.size() && "Link index is out of range!");
138 /// getNumLinks - Return the number of links in a node...
140 unsigned getNumLinks() const { return Links.size(); }
142 /// mergeTypeInfo - This method merges the specified type into the current
143 /// node at the specified offset. This may update the current node's type
144 /// record if this gives more information to the node, it may do nothing to
145 /// the node if this information is already known, or it may merge the node
146 /// completely (and return true) if the information is incompatible with what
147 /// is already known.
149 /// This method returns true if the node is completely folded, otherwise
152 bool mergeTypeInfo(const Type *Ty, unsigned Offset);
154 /// foldNodeCompletely - If we determine that this node has some funny
155 /// behavior happening to it that we cannot represent, we fold it down to a
156 /// single, completely pessimistic, node. This node is represented as a
157 /// single byte with a single TypeEntry of "void" with isArray = true.
159 void foldNodeCompletely();
161 /// isNodeCompletelyFolded - Return true if this node has been completely
162 /// folded down to something that can never be expanded, effectively losing
163 /// all of the field sensitivity that may be present in the node.
165 bool isNodeCompletelyFolded() const;
167 /// setLink - Set the link at the specified offset to the specified
168 /// NodeHandle, replacing what was there. It is uncommon to use this method,
169 /// instead one of the higher level methods should be used, below.
171 void setLink(unsigned Offset, const DSNodeHandle &NH) {
172 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
173 "Pointer offset not aligned correctly!");
174 unsigned Index = Offset >> DS::PointerShift;
175 assert(Index < Links.size() && "Link index is out of range!");
179 /// getPointerSize - Return the size of a pointer for the current target.
181 unsigned getPointerSize() const { return DS::PointerSize; }
183 /// addEdgeTo - Add an edge from the current node to the specified node. This
184 /// can cause merging of nodes in the graph.
186 void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
188 /// mergeWith - Merge this node and the specified node, moving all links to
189 /// and from the argument node into the current node, deleting the node
190 /// argument. Offset indicates what offset the specified node is to be merged
191 /// into the current node.
193 /// The specified node may be a null pointer (in which case, nothing happens).
195 void mergeWith(const DSNodeHandle &NH, unsigned Offset);
197 /// addGlobal - Add an entry for a global value to the Globals list. This
198 /// also marks the node with the 'G' flag if it does not already have it.
200 void addGlobal(GlobalValue *GV);
201 const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
202 std::vector<GlobalValue*> &getGlobals() { return Globals; }
204 void print(std::ostream &O, const DSGraph *G) const;
207 void dropAllReferences() {
211 /// remapLinks - Change all of the Links in the current node according to the
212 /// specified mapping.
213 void remapLinks(std::map<const DSNode*, DSNodeHandle> &OldNodeMap);
216 friend class DSNodeHandle;
217 // addReferrer - Keep the referrer set up to date...
218 void addReferrer(DSNodeHandle *H) { Referrers.push_back(H); }
219 void removeReferrer(DSNodeHandle *H);
223 //===----------------------------------------------------------------------===//
224 // Define inline DSNodeHandle functions that depend on the definition of DSNode
226 inline void DSNodeHandle::setNode(DSNode *n) {
227 if (N) N->removeReferrer(this);
229 if (N) N->addReferrer(this);
230 assert(!N || ((N->NodeType & DSNode::DEAD) == 0));
233 inline bool DSNodeHandle::hasLink(unsigned Num) const {
234 assert(N && "DSNodeHandle does not point to a node yet!");
235 return N->hasLink(Num+Offset);
239 /// getLink - Treat this current node pointer as a pointer to a structure of
240 /// some sort. This method will return the pointer a mem[this+Num]
242 inline const DSNodeHandle &DSNodeHandle::getLink(unsigned Off) const {
243 assert(N && "DSNodeHandle does not point to a node yet!");
244 return N->getLink(Offset+Off);
246 inline DSNodeHandle &DSNodeHandle::getLink(unsigned Off) {
247 assert(N && "DSNodeHandle does not point to a node yet!");
248 return N->getLink(Off+Offset);
251 inline void DSNodeHandle::setLink(unsigned Off, const DSNodeHandle &NH) {
252 assert(N && "DSNodeHandle does not point to a node yet!");
253 N->setLink(Off+Offset, NH);
256 /// addEdgeTo - Add an edge from the current node to the specified node. This
257 /// can cause merging of nodes in the graph.
259 inline void DSNodeHandle::addEdgeTo(unsigned Off, const DSNodeHandle &Node) {
260 assert(N && "DSNodeHandle does not point to a node yet!");
261 N->addEdgeTo(Off+Offset, Node);
264 /// mergeWith - Merge the logical node pointed to by 'this' with the node
265 /// pointed to by 'N'.
267 inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) {
269 N->mergeWith(Node, Offset);
270 else // No node to merge with, so just point to Node
274 inline void DSNodeHandle::swap(DSNodeHandle &NH) {
275 std::swap(Offset, NH.Offset);
278 N->removeReferrer(this);
282 N->removeReferrer(&NH);
283 N->addReferrer(this);