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 dropAllReferences(); // Only needed to satisfy assertion checks...
77 assert(Referrers.empty() && "Referrers to dead node exist!");
81 // Iterator for graph interface...
82 typedef DSNodeIterator iterator;
83 typedef DSNodeIterator const_iterator;
84 inline iterator begin() const; // Defined in DSGraphTraits.h
85 inline iterator end() const;
87 //===--------------------------------------------------
90 /// getSize - Return the maximum number of bytes occupied by this object...
92 unsigned getSize() const { return Size; }
94 // getType - Return the node type of this object...
95 const DSTypeRec &getType() const { return Ty; }
97 /// getReferrers - Return a list of the pointers to this node...
99 const std::vector<DSNodeHandle*> &getReferrers() const { return Referrers; }
101 /// hasNoReferrers - Return true if nothing is pointing to this node at all.
103 bool hasNoReferrers() const { return Referrers.empty(); }
105 /// isModified - Return true if this node may be modified in this context
107 bool isModified() const { return (NodeType & Modified) != 0; }
109 /// isRead - Return true if this node may be read in this context
111 bool isRead() const { return (NodeType & Read) != 0; }
114 /// hasLink - Return true if this memory object has a link in slot #LinkNo
116 bool hasLink(unsigned Offset) const {
117 assert((Offset & ((1 << DS::PointerShift)-1)) == 0 &&
118 "Pointer offset not aligned correctly!");
119 unsigned Index = Offset >> DS::PointerShift;
120 assert(Index < Links.size() && "Link index is out of range!");
121 return Links[Index].getNode();
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 /// mergeTypeInfo - This method merges the specified type into the current
139 /// node at the specified offset. This may update the current node's type
140 /// record if this gives more information to the node, it may do nothing to
141 /// the node if this information is already known, or it may merge the node
142 /// completely (and return true) if the information is incompatible with what
143 /// is already known.
145 /// This method returns true if the node is completely folded, otherwise
148 bool mergeTypeInfo(const Type *Ty, unsigned Offset);
150 /// foldNodeCompletely - If we determine that this node has some funny
151 /// behavior happening to it that we cannot represent, we fold it down to a
152 /// single, completely pessimistic, node. This node is represented as a
153 /// single byte with a single TypeEntry of "void" with isArray = true.
155 void foldNodeCompletely();
157 /// isNodeCompletelyFolded - Return true if this node has been completely
158 /// folded down to something that can never be expanded, effectively losing
159 /// all of the field sensitivity that may be present in the node.
161 bool isNodeCompletelyFolded() const;
163 /// setLink - Set the link at the specified offset to the specified
164 /// NodeHandle, replacing what was there. It is uncommon to use this method,
165 /// instead one of the higher level methods should be used, below.
167 void setLink(unsigned Offset, const DSNodeHandle &NH) {
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!");
175 /// addEdgeTo - Add an edge from the current node to the specified node. This
176 /// can cause merging of nodes in the graph.
178 void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
180 /// mergeWith - Merge this node and the specified node, moving all links to
181 /// and from the argument node into the current node, deleting the node
182 /// argument. Offset indicates what offset the specified node is to be merged
183 /// into the current node.
185 /// The specified node may be a null pointer (in which case, nothing happens).
187 void mergeWith(const DSNodeHandle &NH, unsigned Offset);
189 /// addGlobal - Add an entry for a global value to the Globals list. This
190 /// also marks the node with the 'G' flag if it does not already have it.
192 void addGlobal(GlobalValue *GV);
193 const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
194 std::vector<GlobalValue*> &getGlobals() { return Globals; }
196 void print(std::ostream &O, const DSGraph *G) const;
199 void dropAllReferences() {
203 /// remapLinks - Change all of the Links in the current node according to the
204 /// specified mapping.
205 void remapLinks(std::map<const DSNode*, DSNodeHandle> &OldNodeMap);
208 friend class DSNodeHandle;
209 // addReferrer - Keep the referrer set up to date...
210 void addReferrer(DSNodeHandle *H) { Referrers.push_back(H); }
211 void removeReferrer(DSNodeHandle *H);
215 //===----------------------------------------------------------------------===//
216 // Define inline DSNodeHandle functions that depend on the definition of DSNode
218 inline void DSNodeHandle::setNode(DSNode *n) {
219 if (N) N->removeReferrer(this);
221 if (N) N->addReferrer(this);
222 assert(!N || ((N->NodeType & DSNode::DEAD) == 0));
225 inline bool DSNodeHandle::hasLink(unsigned Num) const {
226 assert(N && "DSNodeHandle does not point to a node yet!");
227 return N->hasLink(Num+Offset);
231 /// getLink - Treat this current node pointer as a pointer to a structure of
232 /// some sort. This method will return the pointer a mem[this+Num]
234 inline const DSNodeHandle &DSNodeHandle::getLink(unsigned Off) const {
235 assert(N && "DSNodeHandle does not point to a node yet!");
236 return N->getLink(Offset+Off);
238 inline DSNodeHandle &DSNodeHandle::getLink(unsigned Off) {
239 assert(N && "DSNodeHandle does not point to a node yet!");
240 return N->getLink(Off+Offset);
243 inline void DSNodeHandle::setLink(unsigned Off, const DSNodeHandle &NH) {
244 assert(N && "DSNodeHandle does not point to a node yet!");
245 N->setLink(Off+Offset, NH);
248 /// addEdgeTo - Add an edge from the current node to the specified node. This
249 /// can cause merging of nodes in the graph.
251 inline void DSNodeHandle::addEdgeTo(unsigned Off, const DSNodeHandle &Node) {
252 assert(N && "DSNodeHandle does not point to a node yet!");
253 N->addEdgeTo(Off+Offset, Node);
256 /// mergeWith - Merge the logical node pointed to by 'this' with the node
257 /// pointed to by 'N'.
259 inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) {
261 N->mergeWith(Node, Offset);
262 else // No node to merge with, so just point to Node