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
21 class DSNode; // Each node in the graph
22 class DSGraph; // A graph for a function
23 class DSNodeIterator; // Data structure graph traversal iterator
26 //===----------------------------------------------------------------------===//
27 /// DSNodeHandle - Implement a "handle" to a data structure node that takes care
28 /// of all of the add/un'refing of the node to prevent the backpointers in the
29 /// graph from getting out of date. This class represents a "pointer" in the
30 /// graph, whose destination is an indexed offset into a node.
36 // Allow construction, destruction, and assignment...
37 DSNodeHandle(DSNode *n = 0, unsigned offs = 0) : N(0), Offset(offs) {
40 DSNodeHandle(const DSNodeHandle &H) : N(0), Offset(H.Offset) { setNode(H.N); }
41 ~DSNodeHandle() { setNode((DSNode*)0); }
42 DSNodeHandle &operator=(const DSNodeHandle &H) {
43 setNode(H.N); Offset = H.Offset;
47 bool operator<(const DSNodeHandle &H) const { // Allow sorting
48 return N < H.N || (N == H.N && Offset < H.Offset);
50 bool operator>(const DSNodeHandle &H) const { return H < *this; }
51 bool operator==(const DSNodeHandle &H) const { // Allow comparison
52 return N == H.N && Offset == H.Offset;
54 bool operator!=(const DSNodeHandle &H) const { return !operator==(H); }
56 // Allow explicit conversion to DSNode...
57 DSNode *getNode() const { return N; }
58 unsigned getOffset() const { return Offset; }
60 inline void setNode(DSNode *N); // Defined inline later...
61 void setOffset(unsigned O) { Offset = O; }
63 void addEdgeTo(unsigned LinkNo, const DSNodeHandle &N);
64 void addEdgeTo(const DSNodeHandle &N) { addEdgeTo(0, N); }
66 /// mergeWith - Merge the logical node pointed to by 'this' with the node
67 /// pointed to by 'N'.
69 void mergeWith(const DSNodeHandle &N);
71 // hasLink - Return true if there is a link at the specified offset...
72 inline bool hasLink(unsigned Num) const;
74 /// getLink - Treat this current node pointer as a pointer to a structure of
75 /// some sort. This method will return the pointer a mem[this+Num]
77 inline const DSNodeHandle *getLink(unsigned Num) const;
78 inline DSNodeHandle *getLink(unsigned Num);
80 inline void setLink(unsigned Num, const DSNodeHandle &NH);
84 //===----------------------------------------------------------------------===//
85 /// DSNode - Data structure node class
87 /// This class represents an untyped memory object of Size bytes. It keeps
88 /// track of any pointers that have been stored into the object as well as the
89 /// different types represented in this object.
92 /// Links - Contains one entry for every _distinct_ pointer field in the
93 /// memory block. These are demand allocated and indexed by the MergeMap
96 std::vector<DSNodeHandle> Links;
98 /// MergeMap - Maps from every byte in the object to a signed byte number.
99 /// This map is neccesary due to the merging that is possible as part of the
100 /// unification algorithm. To merge two distinct bytes of the object together
101 /// into a single logical byte, the indexes for the two bytes are set to the
102 /// same value. This fully general merging is capable of representing all
103 /// manners of array merging if neccesary.
105 /// This map is also used to map outgoing pointers to various byte offsets in
106 /// this data structure node. If this value is >= 0, then it indicates that
107 /// the numbered entry in the Links vector contains the outgoing edge for this
108 /// byte offset. In this way, the Links vector can be demand allocated and
109 /// byte elements of the node may be merged without needing a Link allocated
112 /// Initially, each each element of the MergeMap is assigned a unique negative
113 /// number, which are then merged as the unification occurs.
115 std::vector<signed char> MergeMap;
117 /// Referrers - Keep track of all of the node handles that point to this
118 /// DSNode. These pointers may need to be updated to point to a different
119 /// node if this node gets merged with it.
121 std::vector<DSNodeHandle*> Referrers;
123 /// TypeRec - This structure is used to represent a single type that is held
126 const Type *Ty; // The type itself...
127 unsigned Offset; // The offset in the node
128 bool isArray; // Have we accessed an array of elements?
130 TypeRec() : Ty(0), Offset(0), isArray(false) {}
131 TypeRec(const Type *T, unsigned O) : Ty(T), Offset(O), isArray(false) {}
133 bool operator<(const TypeRec &TR) const {
134 // Sort first by offset!
135 return Offset < TR.Offset || (Offset == TR.Offset && Ty < TR.Ty);
137 bool operator==(const TypeRec &TR) const {
138 return Ty == TR.Ty && Offset == TR.Offset;
140 bool operator!=(const TypeRec &TR) const { return !operator==(TR); }
143 /// TypeEntries - As part of the merging process of this algorithm, nodes of
144 /// different types can be represented by this single DSNode. This vector is
147 std::vector<TypeRec> TypeEntries;
149 /// Globals - The list of global values that are merged into this node.
151 std::vector<GlobalValue*> Globals;
153 void operator=(const DSNode &); // DO NOT IMPLEMENT
156 ShadowNode = 0, // Nothing is known about this node...
157 ScalarNode = 1 << 0, // Scalar of the current function contains this value
158 AllocaNode = 1 << 1, // This node was allocated with alloca
159 NewNode = 1 << 2, // This node was allocated with malloc
160 GlobalNode = 1 << 3, // This node was allocated by a global var decl
161 Incomplete = 1 << 4, // This node may not be complete
162 Modified = 1 << 5, // This node is modified in this context
163 Read = 1 << 6, // This node is read in this context
166 /// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
167 /// to the nodes in the data structure graph, so it is possible to have nodes
168 /// with a value of 0 for their NodeType. Scalar and Alloca markers go away
169 /// when function graphs are inlined.
171 unsigned char NodeType;
173 DSNode(enum NodeTy NT, const Type *T);
174 DSNode(const DSNode &);
178 dropAllReferences(); // Only needed to satisfy assertion checks...
179 assert(Referrers.empty() && "Referrers to dead node exist!");
183 // Iterator for graph interface...
184 typedef DSNodeIterator iterator;
185 typedef DSNodeIterator const_iterator;
186 inline iterator begin() const; // Defined in DSGraphTraits.h
187 inline iterator end() const;
189 //===--------------------------------------------------
192 /// getSize - Return the maximum number of bytes occupied by this object...
194 unsigned getSize() const { return MergeMap.size(); }
196 // getTypeEntries - Return the possible types and their offsets in this object
197 const std::vector<TypeRec> &getTypeEntries() const { return TypeEntries; }
199 /// getReferrers - Return a list of the pointers to this node...
201 const std::vector<DSNodeHandle*> &getReferrers() const { return Referrers; }
203 /// isModified - Return true if this node may be modified in this context
205 bool isModified() const { return (NodeType & Modified) != 0; }
207 /// isRead - Return true if this node may be read in this context
209 bool isRead() const { return (NodeType & Read) != 0; }
212 /// hasLink - Return true if this memory object has a link at the specified
215 bool hasLink(unsigned i) const {
216 assert(i < getSize() && "Field Link index is out of range!");
217 return MergeMap[i] >= 0;
220 DSNodeHandle *getLink(unsigned i) {
222 return &Links[MergeMap[i]];
225 const DSNodeHandle *getLink(unsigned i) const {
227 return &Links[MergeMap[i]];
231 int getMergeMapLabel(unsigned i) const {
232 assert(i < MergeMap.size() && "MergeMap index out of range!");
236 /// setLink - Set the link at the specified offset to the specified
237 /// NodeHandle, replacing what was there. It is uncommon to use this method,
238 /// instead one of the higher level methods should be used, below.
240 void setLink(unsigned i, const DSNodeHandle &NH);
242 /// addEdgeTo - Add an edge from the current node to the specified node. This
243 /// can cause merging of nodes in the graph.
245 void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
247 /// mergeWith - Merge this node and the specified node, moving all links to
248 /// and from the argument node into the current node, deleting the node
249 /// argument. Offset indicates what offset the specified node is to be merged
250 /// into the current node.
252 /// The specified node may be a null pointer (in which case, nothing happens).
254 void mergeWith(const DSNodeHandle &NH, unsigned Offset);
256 /// mergeIndexes - If we discover that two indexes are equivalent and must be
257 /// merged, this function is used to do the dirty work.
259 void mergeIndexes(unsigned idx1, unsigned idx2) {
260 assert(idx1 < getSize() && idx2 < getSize() && "Indexes out of range!");
261 signed char MV1 = MergeMap[idx1];
262 signed char MV2 = MergeMap[idx2];
264 mergeMappedValues(MV1, MV2);
268 /// addGlobal - Add an entry for a global value to the Globals list. This
269 /// also marks the node with the 'G' flag if it does not already have it.
271 void addGlobal(GlobalValue *GV);
272 const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
273 std::vector<GlobalValue*> &getGlobals() { return Globals; }
275 void print(std::ostream &O, const DSGraph *G) const;
278 void dropAllReferences() {
282 /// remapLinks - Change all of the Links in the current node according to the
283 /// specified mapping.
284 void remapLinks(std::map<const DSNode*, DSNode*> &OldNodeMap);
287 friend class DSNodeHandle;
288 // addReferrer - Keep the referrer set up to date...
289 void addReferrer(DSNodeHandle *H) { Referrers.push_back(H); }
290 void removeReferrer(DSNodeHandle *H);
292 /// rewriteMergeMap - Loop over the mergemap, replacing any references to the
293 /// index From to be references to the index To.
295 void rewriteMergeMap(signed char From, signed char To) {
296 assert(From != To && "Cannot change something into itself!");
297 for (unsigned i = 0, e = MergeMap.size(); i != e; ++i)
298 if (MergeMap[i] == From)
302 /// mergeMappedValues - This is the higher level form of rewriteMergeMap. It
303 /// is fully capable of merging links together if neccesary as well as simply
304 /// rewriting the map entries.
306 void mergeMappedValues(signed char V1, signed char V2);
310 //===----------------------------------------------------------------------===//
311 // Define inline DSNodeHandle functions that depend on the definition of DSNode
314 inline void DSNodeHandle::setNode(DSNode *n) {
315 if (N) N->removeReferrer(this);
317 if (N) N->addReferrer(this);
320 inline bool DSNodeHandle::hasLink(unsigned Num) const {
321 assert(N && "DSNodeHandle does not point to a node yet!");
322 return N->hasLink(Num+Offset);
326 /// getLink - Treat this current node pointer as a pointer to a structure of
327 /// some sort. This method will return the pointer a mem[this+Num]
329 inline const DSNodeHandle *DSNodeHandle::getLink(unsigned Num) const {
330 assert(N && "DSNodeHandle does not point to a node yet!");
331 return N->getLink(Num+Offset);
333 inline DSNodeHandle *DSNodeHandle::getLink(unsigned Num) {
334 assert(N && "DSNodeHandle does not point to a node yet!");
335 return N->getLink(Num+Offset);
338 inline void DSNodeHandle::setLink(unsigned Num, const DSNodeHandle &NH) {
339 assert(N && "DSNodeHandle does not point to a node yet!");
340 N->setLink(Num+Offset, NH);
343 /// addEdgeTo - Add an edge from the current node to the specified node. This
344 /// can cause merging of nodes in the graph.
346 inline void DSNodeHandle::addEdgeTo(unsigned LinkNo, const DSNodeHandle &Node) {
347 assert(N && "DSNodeHandle does not point to a node yet!");
348 N->addEdgeTo(LinkNo+Offset, Node);
351 /// mergeWith - Merge the logical node pointed to by 'this' with the node
352 /// pointed to by 'N'.
354 inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) {
355 assert(N && "DSNodeHandle does not point to a node yet!");
356 N->mergeWith(Node, Offset);
360 //===----------------------------------------------------------------------===//
361 /// DSCallSite - Representation of a call site via its call instruction,
362 /// the DSNode handle for the callee function (or function pointer), and
363 /// the DSNode handles for the function arguments.
366 CallInst *Inst; // Actual call site
367 DSNodeHandle RetVal; // Returned value
368 DSNodeHandle Callee; // The function node called
369 std::vector<DSNodeHandle> CallArgs; // The pointer arguments
371 static DSNode *mapLookup(const DSNode *Node,
372 const std::map<const DSNode*, DSNode*> &NodeMap) {
373 if (Node == 0) return 0;
374 std::map<const DSNode*, DSNode*>::const_iterator I = NodeMap.find(Node);
375 assert(I != NodeMap.end() && "Not not in mapping!");
379 DSCallSite(); // DO NOT IMPLEMENT
381 /// Constructor. Note - This ctor destroys the argument vector passed in. On
382 /// exit, the argument vector is empty.
384 DSCallSite(CallInst &inst, const DSNodeHandle &rv, const DSNodeHandle &callee,
385 std::vector<DSNodeHandle> &Args)
386 : Inst(&inst), RetVal(rv), Callee(callee) {
390 DSCallSite(const DSCallSite &DSCS) // Simple copy ctor
391 : Inst(DSCS.Inst), RetVal(DSCS.RetVal),
392 Callee(DSCS.Callee), CallArgs(DSCS.CallArgs) {}
394 /// Mapping copy constructor - This constructor takes a preexisting call site
395 /// to copy plus a map that specifies how the links should be transformed.
396 /// This is useful when moving a call site from one graph to another.
398 DSCallSite(const DSCallSite &FromCall,
399 const std::map<const DSNode*, DSNode*> &NodeMap) {
400 Inst = FromCall.Inst;
401 RetVal.setOffset(FromCall.RetVal.getOffset());
402 RetVal.setNode(mapLookup(FromCall.RetVal.getNode(), NodeMap));
403 Callee.setOffset(FromCall.Callee.getOffset());
404 Callee.setNode(mapLookup(FromCall.Callee.getNode(), NodeMap));
405 CallArgs.reserve(FromCall.CallArgs.size());
407 for (unsigned i = 0, e = FromCall.CallArgs.size(); i != e; ++i) {
408 const DSNodeHandle &OldNH = FromCall.CallArgs[i];
409 CallArgs.push_back(DSNodeHandle(mapLookup(OldNH.getNode(), NodeMap),
414 // Accessor functions...
415 Function &getCaller() const;
416 CallInst &getCallInst() const { return *Inst; }
417 DSNodeHandle &getRetVal() { return RetVal; }
418 DSNodeHandle &getCallee() { return Callee; }
419 const DSNodeHandle &getRetVal() const { return RetVal; }
420 const DSNodeHandle &getCallee() const { return Callee; }
421 unsigned getNumPtrArgs() const { return CallArgs.size(); }
423 DSNodeHandle &getPtrArg(unsigned i) {
424 assert(i < CallArgs.size() && "Argument to getPtrArgNode is out of range!");
427 const DSNodeHandle &getPtrArg(unsigned i) const {
428 assert(i < CallArgs.size() && "Argument to getPtrArgNode is out of range!");
432 bool operator<(const DSCallSite &CS) const {
433 if (RetVal < CS.RetVal) return true;
434 if (RetVal > CS.RetVal) return false;
435 if (Callee < CS.Callee) return true;
436 if (Callee > CS.Callee) return false;
437 return CallArgs < CS.CallArgs;
440 bool operator==(const DSCallSite &CS) const {
441 return RetVal == CS.RetVal && Callee == CS.Callee &&
442 CallArgs == CS.CallArgs;
447 //===----------------------------------------------------------------------===//
448 /// DSGraph - The graph that represents a function.
452 std::vector<DSNode*> Nodes;
453 DSNodeHandle RetNode; // Node that gets returned...
454 std::map<Value*, DSNodeHandle> ValueMap;
457 // GlobalsGraph -- Reference to the common graph of globally visible objects.
458 // This includes GlobalValues, New nodes, Cast nodes, and Calls.
460 GlobalDSGraph* GlobalsGraph;
463 // FunctionCalls - This vector maintains a single entry for each call
464 // instruction in the current graph. Each call entry contains DSNodeHandles
465 // that refer to the arguments that are passed into the function call. The
466 // first entry in the vector is the scalar that holds the return value for the
467 // call, the second is the function scalar being invoked, and the rest are
468 // pointer arguments to the function.
470 std::vector<DSCallSite> FunctionCalls;
472 void operator=(const DSGraph &); // DO NOT IMPLEMENT
474 DSGraph() : Func(0) {} // Create a new, empty, DSGraph.
475 DSGraph(Function &F); // Compute the local DSGraph
476 DSGraph(const DSGraph &DSG); // Copy ctor
479 bool hasFunction() const { return Func != 0; }
480 Function &getFunction() const { return *Func; }
482 /// getNodes - Get a vector of all the nodes in the graph
484 const std::vector<DSNode*> &getNodes() const { return Nodes; }
485 std::vector<DSNode*> &getNodes() { return Nodes; }
487 /// addNode - Add a new node to the graph.
489 void addNode(DSNode *N) { Nodes.push_back(N); }
491 /// getValueMap - Get a map that describes what the nodes the scalars in this
492 /// function point to...
494 std::map<Value*, DSNodeHandle> &getValueMap() { return ValueMap; }
495 const std::map<Value*, DSNodeHandle> &getValueMap() const { return ValueMap;}
497 std::vector<DSCallSite> &getFunctionCalls() {
498 return FunctionCalls;
500 const std::vector<DSCallSite> &getFunctionCalls() const {
501 return FunctionCalls;
504 /// getNodeForValue - Given a value that is used or defined in the body of the
505 /// current function, return the DSNode that it points to.
507 DSNodeHandle &getNodeForValue(Value *V) { return ValueMap[V]; }
509 const DSNodeHandle &getRetNode() const { return RetNode; }
510 DSNodeHandle &getRetNode() { return RetNode; }
512 unsigned getGraphSize() const {
516 void print(std::ostream &O) const;
518 void writeGraphToFile(std::ostream &O, const std::string &GraphName) const;
520 // maskNodeTypes - Apply a mask to all of the node types in the graph. This
521 // is useful for clearing out markers like Scalar or Incomplete.
523 void maskNodeTypes(unsigned char Mask);
524 void maskIncompleteMarkers() { maskNodeTypes(~DSNode::Incomplete); }
526 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
527 // modified by other functions that have not been resolved yet. This marks
528 // nodes that are reachable through three sources of "unknownness":
529 // Global Variables, Function Calls, and Incoming Arguments
531 // For any node that may have unknown components (because something outside
532 // the scope of current analysis may have modified it), the 'Incomplete' flag
533 // is added to the NodeType.
535 void markIncompleteNodes(bool markFormalArgs = true);
537 // removeTriviallyDeadNodes - After the graph has been constructed, this
538 // method removes all unreachable nodes that are created because they got
539 // merged with other nodes in the graph.
541 void removeTriviallyDeadNodes(bool KeepAllGlobals = false);
543 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
544 // subgraphs that are unreachable. This often occurs because the data
545 // structure doesn't "escape" into it's caller, and thus should be eliminated
546 // from the caller's graph entirely. This is only appropriate to use when
549 void removeDeadNodes(bool KeepAllGlobals = false, bool KeepCalls = true);
551 // cloneInto - Clone the specified DSGraph into the current graph, returning
552 // the Return node of the graph. The translated ValueMap for the old function
553 // is filled into the OldValMap member.
554 // If StripScalars (StripAllocas) is set to true, Scalar (Alloca) markers
555 // are removed from the graph as the graph is being cloned.
556 // If CopyCallers is set to true, the PendingCallers list is copied.
557 // If CopyOrigCalls is set to true, the OrigFunctionCalls list is copied.
559 DSNodeHandle cloneInto(const DSGraph &G,
560 std::map<Value*, DSNodeHandle> &OldValMap,
561 std::map<const DSNode*, DSNode*> &OldNodeMap,
562 bool StripScalars = false, bool StripAllocas = false,
563 bool CopyCallers = true, bool CopyOrigCalls = true);
566 // cloneGlobalInto - Clone the given global node (or the node for the given
567 // GlobalValue) from the GlobalsGraph and all its target links (recursively).
569 DSNode* cloneGlobalInto(const DSNode* GNode);
570 DSNode* cloneGlobalInto(GlobalValue* GV) {
571 assert(!GV || (((DSGraph*) GlobalsGraph)->ValueMap[GV] != 0));
572 return GV? cloneGlobalInto(((DSGraph*) GlobalsGraph)->ValueMap[GV]) : 0;
577 bool isNodeDead(DSNode *N);