1 //===- DSGraph.h - Represent a collection of data structures ----*- C++ -*-===//
3 // This header defines the primative classes that make up a data structure
6 //===----------------------------------------------------------------------===//
8 #ifndef LLVM_ANALYSIS_DSGRAPH_H
9 #define LLVM_ANALYSIS_DSGRAPH_H
19 class DSNode; // Each node in the graph
20 class DSGraph; // A graph for a function
21 class DSNodeIterator; // Data structure graph traversal iterator
23 //===----------------------------------------------------------------------===//
24 /// DSNodeHandle - Implement a "handle" to a data structure node that takes care
25 /// of all of the add/un'refing of the node to prevent the backpointers in the
26 /// graph from getting out of date. This class represents a "pointer" in the
27 /// graph, whose destination is an indexed offset into a node.
33 // Allow construction, destruction, and assignment...
34 DSNodeHandle(DSNode *n = 0, unsigned offs = 0) : N(0), Offset(offs) {
37 DSNodeHandle(const DSNodeHandle &H) : N(0), Offset(H.Offset) { setNode(H.N); }
38 ~DSNodeHandle() { setNode((DSNode*)0); }
39 DSNodeHandle &operator=(const DSNodeHandle &H) {
40 setNode(H.N); Offset = H.Offset;
44 bool operator<(const DSNodeHandle &H) const { // Allow sorting
45 return N < H.N || (N == H.N && Offset < H.Offset);
47 bool operator==(const DSNodeHandle &H) const { // Allow comparison
48 return N == H.N && Offset == H.Offset;
50 bool operator!=(const DSNodeHandle &H) const { return !operator==(H); }
52 // Allow explicit conversion to DSNode...
53 DSNode *getNode() const { return N; }
54 unsigned getOffset() const { return Offset; }
56 inline void setNode(DSNode *N); // Defined inline later...
57 void setOffset(unsigned O) { Offset = O; }
59 void addEdgeTo(unsigned LinkNo, const DSNodeHandle &N);
60 void addEdgeTo(const DSNodeHandle &N) { addEdgeTo(0, N); }
62 /// mergeWith - Merge the logical node pointed to by 'this' with the node
63 /// pointed to by 'N'.
65 void mergeWith(const DSNodeHandle &N);
67 // hasLink - Return true if there is a link at the specified offset...
68 inline bool hasLink(unsigned Num) const;
70 /// getLink - Treat this current node pointer as a pointer to a structure of
71 /// some sort. This method will return the pointer a mem[this+Num]
73 inline const DSNodeHandle *getLink(unsigned Num) const;
74 inline DSNodeHandle *getLink(unsigned Num);
76 inline void setLink(unsigned Num, const DSNodeHandle &NH);
80 //===----------------------------------------------------------------------===//
81 /// DSNode - Data structure node class
83 /// This class represents an untyped memory object of Size bytes. It keeps
84 /// track of any pointers that have been stored into the object as well as the
85 /// different types represented in this object.
88 /// Links - Contains one entry for every _distinct_ pointer field in the
89 /// memory block. These are demand allocated and indexed by the MergeMap
92 std::vector<DSNodeHandle> Links;
94 /// MergeMap - Maps from every byte in the object to a signed byte number.
95 /// This map is neccesary due to the merging that is possible as part of the
96 /// unification algorithm. To merge two distinct bytes of the object together
97 /// into a single logical byte, the indexes for the two bytes are set to the
98 /// same value. This fully general merging is capable of representing all
99 /// manners of array merging if neccesary.
101 /// This map is also used to map outgoing pointers to various byte offsets in
102 /// this data structure node. If this value is >= 0, then it indicates that
103 /// the numbered entry in the Links vector contains the outgoing edge for this
104 /// byte offset. In this way, the Links vector can be demand allocated and
105 /// byte elements of the node may be merged without needing a Link allocated
108 /// Initially, each each element of the MergeMap is assigned a unique negative
109 /// number, which are then merged as the unification occurs.
111 std::vector<signed char> MergeMap;
113 /// Referrers - Keep track of all of the node handles that point to this
114 /// DSNode. These pointers may need to be updated to point to a different
115 /// node if this node gets merged with it.
117 std::vector<DSNodeHandle*> Referrers;
119 /// TypeEntries - As part of the merging process of this algorithm, nodes of
120 /// different types can be represented by this single DSNode. This vector is
127 TypeRec() : Ty(0), Offset(0) {}
128 TypeRec(const Type *T, unsigned O) : Ty(T), Offset(O) {}
130 bool operator<(const TypeRec &TR) const {
131 // Sort first by offset!
132 return Offset < TR.Offset || (Offset == TR.Offset && Ty < TR.Ty);
134 bool operator==(const TypeRec &TR) const {
135 return Ty == TR.Ty && Offset == TR.Offset;
137 bool operator!=(const TypeRec &TR) const { return !operator==(TR); }
140 std::vector<TypeRec> TypeEntries;
142 /// Globals - The list of global values that are merged into this node.
144 std::vector<GlobalValue*> Globals;
146 void operator=(const DSNode &); // DO NOT IMPLEMENT
149 ShadowNode = 0, // Nothing is known about this node...
150 ScalarNode = 1 << 0, // Scalar of the current function contains this value
151 AllocaNode = 1 << 1, // This node was allocated with alloca
152 NewNode = 1 << 2, // This node was allocated with malloc
153 GlobalNode = 1 << 3, // This node was allocated by a global var decl
154 Incomplete = 1 << 4, // This node may not be complete
155 Modified = 1 << 5, // This node is modified in this context
156 Read = 1 << 6, // This node is read in this context
159 /// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
160 /// to the nodes in the data structure graph, so it is possible to have nodes
161 /// with a value of 0 for their NodeType. Scalar and Alloca markers go away
162 /// when function graphs are inlined.
164 unsigned char NodeType;
166 DSNode(enum NodeTy NT, const Type *T);
167 DSNode(const DSNode &);
171 dropAllReferences(); // Only needed to satisfy assertion checks...
172 assert(Referrers.empty() && "Referrers to dead node exist!");
176 // Iterator for graph interface...
177 typedef DSNodeIterator iterator;
178 typedef DSNodeIterator const_iterator;
179 inline iterator begin() const; // Defined in DSGraphTraits.h
180 inline iterator end() const;
182 //===--------------------------------------------------
185 /// getSize - Return the maximum number of bytes occupied by this object...
187 unsigned getSize() const { return MergeMap.size(); }
189 // getTypeEntries - Return the possible types and their offsets in this object
190 const std::vector<TypeRec> &getTypeEntries() const { return TypeEntries; }
192 /// getReferrers - Return a list of the pointers to this node...
194 const std::vector<DSNodeHandle*> &getReferrers() const { return Referrers; }
196 /// isModified - Return true if this node may be modified in this context
198 bool isModified() const { return (NodeType & Modified) != 0; }
200 /// isRead - Return true if this node may be read in this context
202 bool isRead() const { return (NodeType & Read) != 0; }
205 /// hasLink - Return true if this memory object has a link at the specified
208 bool hasLink(unsigned i) const {
209 assert(i < getSize() && "Field Link index is out of range!");
210 return MergeMap[i] >= 0;
213 DSNodeHandle *getLink(unsigned i) {
215 return &Links[MergeMap[i]];
218 const DSNodeHandle *getLink(unsigned i) const {
220 return &Links[MergeMap[i]];
224 int getMergeMapLabel(unsigned i) const {
225 assert(i < MergeMap.size() && "MergeMap index out of range!");
229 /// setLink - Set the link at the specified offset to the specified
230 /// NodeHandle, replacing what was there. It is uncommon to use this method,
231 /// instead one of the higher level methods should be used, below.
233 void setLink(unsigned i, const DSNodeHandle &NH);
235 /// addEdgeTo - Add an edge from the current node to the specified node. This
236 /// can cause merging of nodes in the graph.
238 void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
240 /// mergeWith - Merge this node and the specified node, moving all links to
241 /// and from the argument node into the current node, deleting the node
242 /// argument. Offset indicates what offset the specified node is to be merged
243 /// into the current node.
245 /// The specified node may be a null pointer (in which case, nothing happens).
247 void mergeWith(const DSNodeHandle &NH, unsigned Offset);
249 /// mergeIndexes - If we discover that two indexes are equivalent and must be
250 /// merged, this function is used to do the dirty work.
252 void mergeIndexes(unsigned idx1, unsigned idx2) {
253 assert(idx1 < getSize() && idx2 < getSize() && "Indexes out of range!");
254 signed char MV1 = MergeMap[idx1];
255 signed char MV2 = MergeMap[idx2];
257 mergeMappedValues(MV1, MV2);
261 /// addGlobal - Add an entry for a global value to the Globals list. This
262 /// also marks the node with the 'G' flag if it does not already have it.
264 void addGlobal(GlobalValue *GV);
265 const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
266 std::vector<GlobalValue*> &getGlobals() { return Globals; }
268 void print(std::ostream &O, const DSGraph *G) const;
271 void dropAllReferences() {
275 /// remapLinks - Change all of the Links in the current node according to the
276 /// specified mapping.
277 void remapLinks(std::map<const DSNode*, DSNode*> &OldNodeMap);
280 friend class DSNodeHandle;
281 // addReferrer - Keep the referrer set up to date...
282 void addReferrer(DSNodeHandle *H) { Referrers.push_back(H); }
283 void removeReferrer(DSNodeHandle *H);
285 /// rewriteMergeMap - Loop over the mergemap, replacing any references to the
286 /// index From to be references to the index To.
288 void rewriteMergeMap(signed char From, signed char To) {
289 assert(From != To && "Cannot change something into itself!");
290 for (unsigned i = 0, e = MergeMap.size(); i != e; ++i)
291 if (MergeMap[i] == From)
295 /// mergeMappedValues - This is the higher level form of rewriteMergeMap. It
296 /// is fully capable of merging links together if neccesary as well as simply
297 /// rewriting the map entries.
299 void mergeMappedValues(signed char V1, signed char V2);
303 //===----------------------------------------------------------------------===//
304 // Define inline DSNodeHandle functions that depend on the definition of DSNode
307 inline void DSNodeHandle::setNode(DSNode *n) {
308 if (N) N->removeReferrer(this);
310 if (N) N->addReferrer(this);
313 inline bool DSNodeHandle::hasLink(unsigned Num) const {
314 assert(N && "DSNodeHandle does not point to a node yet!");
315 return N->hasLink(Num+Offset);
319 /// getLink - Treat this current node pointer as a pointer to a structure of
320 /// some sort. This method will return the pointer a mem[this+Num]
322 inline const DSNodeHandle *DSNodeHandle::getLink(unsigned Num) const {
323 assert(N && "DSNodeHandle does not point to a node yet!");
324 return N->getLink(Num+Offset);
326 inline DSNodeHandle *DSNodeHandle::getLink(unsigned Num) {
327 assert(N && "DSNodeHandle does not point to a node yet!");
328 return N->getLink(Num+Offset);
331 inline void DSNodeHandle::setLink(unsigned Num, const DSNodeHandle &NH) {
332 assert(N && "DSNodeHandle does not point to a node yet!");
333 N->setLink(Num+Offset, NH);
336 /// addEdgeTo - Add an edge from the current node to the specified node. This
337 /// can cause merging of nodes in the graph.
339 inline void DSNodeHandle::addEdgeTo(unsigned LinkNo, const DSNodeHandle &Node) {
340 assert(N && "DSNodeHandle does not point to a node yet!");
341 N->addEdgeTo(LinkNo+Offset, Node);
344 /// mergeWith - Merge the logical node pointed to by 'this' with the node
345 /// pointed to by 'N'.
347 inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) {
348 assert(N && "DSNodeHandle does not point to a node yet!");
349 N->mergeWith(Node, Offset);
353 //===----------------------------------------------------------------------===//
354 /// DSGraph - The graph that represents a function.
358 std::vector<DSNode*> Nodes;
359 DSNodeHandle RetNode; // Node that gets returned...
360 std::map<Value*, DSNodeHandle> ValueMap;
363 // GlobalsGraph -- Reference to the common graph of globally visible objects.
364 // This includes GlobalValues, New nodes, Cast nodes, and Calls.
366 GlobalDSGraph* GlobalsGraph;
369 // FunctionCalls - This vector maintains a single entry for each call
370 // instruction in the current graph. Each call entry contains DSNodeHandles
371 // that refer to the arguments that are passed into the function call. The
372 // first entry in the vector is the scalar that holds the return value for the
373 // call, the second is the function scalar being invoked, and the rest are
374 // pointer arguments to the function.
376 std::vector<std::vector<DSNodeHandle> > FunctionCalls;
378 void operator=(const DSGraph &); // DO NOT IMPLEMENT
380 DSGraph() : Func(0) {} // Create a new, empty, DSGraph.
381 DSGraph(Function &F); // Compute the local DSGraph
382 DSGraph(const DSGraph &DSG); // Copy ctor
385 bool hasFunction() const { return Func != 0; }
386 Function &getFunction() const { return *Func; }
388 /// getNodes - Get a vector of all the nodes in the graph
390 const std::vector<DSNode*> &getNodes() const { return Nodes; }
391 std::vector<DSNode*> &getNodes() { return Nodes; }
393 /// addNode - Add a new node to the graph.
395 void addNode(DSNode *N) { Nodes.push_back(N); }
397 /// getValueMap - Get a map that describes what the nodes the scalars in this
398 /// function point to...
400 std::map<Value*, DSNodeHandle> &getValueMap() { return ValueMap; }
401 const std::map<Value*, DSNodeHandle> &getValueMap() const { return ValueMap;}
403 std::vector<std::vector<DSNodeHandle> > &getFunctionCalls() {
404 return FunctionCalls;
406 const std::vector<std::vector<DSNodeHandle> > &getFunctionCalls() const {
407 return FunctionCalls;
410 /// getNodeForValue - Given a value that is used or defined in the body of the
411 /// current function, return the DSNode that it points to.
413 DSNodeHandle &getNodeForValue(Value *V) { return ValueMap[V]; }
415 const DSNodeHandle &getRetNode() const { return RetNode; }
416 DSNodeHandle &getRetNode() { return RetNode; }
418 unsigned getGraphSize() const {
422 void print(std::ostream &O) const;
424 void writeGraphToFile(std::ostream &O, const std::string &GraphName) const;
426 // maskNodeTypes - Apply a mask to all of the node types in the graph. This
427 // is useful for clearing out markers like Scalar or Incomplete.
429 void maskNodeTypes(unsigned char Mask);
430 void maskIncompleteMarkers() { maskNodeTypes(~DSNode::Incomplete); }
432 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
433 // modified by other functions that have not been resolved yet. This marks
434 // nodes that are reachable through three sources of "unknownness":
435 // Global Variables, Function Calls, and Incoming Arguments
437 // For any node that may have unknown components (because something outside
438 // the scope of current analysis may have modified it), the 'Incomplete' flag
439 // is added to the NodeType.
441 void markIncompleteNodes(bool markFormalArgs = true);
443 // removeTriviallyDeadNodes - After the graph has been constructed, this
444 // method removes all unreachable nodes that are created because they got
445 // merged with other nodes in the graph.
447 void removeTriviallyDeadNodes(bool KeepAllGlobals = false);
449 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
450 // subgraphs that are unreachable. This often occurs because the data
451 // structure doesn't "escape" into it's caller, and thus should be eliminated
452 // from the caller's graph entirely. This is only appropriate to use when
455 void removeDeadNodes(bool KeepAllGlobals = false, bool KeepCalls = true);
457 // cloneInto - Clone the specified DSGraph into the current graph, returning
458 // the Return node of the graph. The translated ValueMap for the old function
459 // is filled into the OldValMap member.
460 // If StripScalars (StripAllocas) is set to true, Scalar (Alloca) markers
461 // are removed from the graph as the graph is being cloned.
462 // If CopyCallers is set to true, the PendingCallers list is copied.
463 // If CopyOrigCalls is set to true, the OrigFunctionCalls list is copied.
465 DSNodeHandle cloneInto(const DSGraph &G,
466 std::map<Value*, DSNodeHandle> &OldValMap,
467 std::map<const DSNode*, DSNode*> &OldNodeMap,
468 bool StripScalars = false, bool StripAllocas = false,
469 bool CopyCallers = true, bool CopyOrigCalls = true);
472 // cloneGlobalInto - Clone the given global node (or the node for the given
473 // GlobalValue) from the GlobalsGraph and all its target links (recursively).
475 DSNode* cloneGlobalInto(const DSNode* GNode);
476 DSNode* cloneGlobalInto(GlobalValue* GV) {
477 assert(!GV || (((DSGraph*) GlobalsGraph)->ValueMap[GV] != 0));
478 return GV? cloneGlobalInto(((DSGraph*) GlobalsGraph)->ValueMap[GV]) : 0;
483 bool isNodeDead(DSNode *N);