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
22 class DSNode; // Each node in the graph
23 class DSGraph; // A graph for a function
24 class DSNodeIterator; // Data structure graph traversal iterator
27 //===----------------------------------------------------------------------===//
28 /// DSNodeHandle - Implement a "handle" to a data structure node that takes care
29 /// of all of the add/un'refing of the node to prevent the backpointers in the
30 /// graph from getting out of date. This class represents a "pointer" in the
31 /// graph, whose destination is an indexed offset into a node.
37 // Allow construction, destruction, and assignment...
38 DSNodeHandle(DSNode *n = 0, unsigned offs = 0) : N(0), Offset(offs) {
41 DSNodeHandle(const DSNodeHandle &H) : N(0), Offset(H.Offset) { setNode(H.N); }
42 ~DSNodeHandle() { setNode((DSNode*)0); }
43 DSNodeHandle &operator=(const DSNodeHandle &H) {
44 setNode(H.N); Offset = H.Offset;
48 bool operator<(const DSNodeHandle &H) const { // Allow sorting
49 return N < H.N || (N == H.N && Offset < H.Offset);
51 bool operator>(const DSNodeHandle &H) const { return H < *this; }
52 bool operator==(const DSNodeHandle &H) const { // Allow comparison
53 return N == H.N && Offset == H.Offset;
55 bool operator!=(const DSNodeHandle &H) const { return !operator==(H); }
57 // Allow explicit conversion to DSNode...
58 DSNode *getNode() const { return N; }
59 unsigned getOffset() const { return Offset; }
61 inline void setNode(DSNode *N); // Defined inline later...
62 void setOffset(unsigned O) { Offset = O; }
64 void addEdgeTo(unsigned LinkNo, const DSNodeHandle &N);
65 void addEdgeTo(const DSNodeHandle &N) { addEdgeTo(0, N); }
67 /// mergeWith - Merge the logical node pointed to by 'this' with the node
68 /// pointed to by 'N'.
70 void mergeWith(const DSNodeHandle &N);
72 // hasLink - Return true if there is a link at the specified offset...
73 inline bool hasLink(unsigned Num) const;
75 /// getLink - Treat this current node pointer as a pointer to a structure of
76 /// some sort. This method will return the pointer a mem[this+Num]
78 inline const DSNodeHandle *getLink(unsigned Num) const;
79 inline DSNodeHandle *getLink(unsigned Num);
81 inline void setLink(unsigned Num, const DSNodeHandle &NH);
85 //===----------------------------------------------------------------------===//
86 /// DSNode - Data structure node class
88 /// This class represents an untyped memory object of Size bytes. It keeps
89 /// track of any pointers that have been stored into the object as well as the
90 /// different types represented in this object.
93 /// Links - Contains one entry for every _distinct_ pointer field in the
94 /// memory block. These are demand allocated and indexed by the MergeMap
97 std::vector<DSNodeHandle> Links;
99 /// MergeMap - Maps from every byte in the object to a signed byte number.
100 /// This map is neccesary due to the merging that is possible as part of the
101 /// unification algorithm. To merge two distinct bytes of the object together
102 /// into a single logical byte, the indexes for the two bytes are set to the
103 /// same value. This fully general merging is capable of representing all
104 /// manners of array merging if neccesary.
106 /// This map is also used to map outgoing pointers to various byte offsets in
107 /// this data structure node. If this value is >= 0, then it indicates that
108 /// the numbered entry in the Links vector contains the outgoing edge for this
109 /// byte offset. In this way, the Links vector can be demand allocated and
110 /// byte elements of the node may be merged without needing a Link allocated
113 /// Initially, each each element of the MergeMap is assigned a unique negative
114 /// number, which are then merged as the unification occurs.
116 std::vector<signed char> MergeMap;
118 /// Referrers - Keep track of all of the node handles that point to this
119 /// DSNode. These pointers may need to be updated to point to a different
120 /// node if this node gets merged with it.
122 std::vector<DSNodeHandle*> Referrers;
124 /// TypeRec - This structure is used to represent a single type that is held
127 const Type *Ty; // The type itself...
128 unsigned Offset; // The offset in the node
129 bool isArray; // Have we accessed an array of elements?
131 TypeRec() : Ty(0), Offset(0), isArray(false) {}
132 TypeRec(const Type *T, unsigned O) : Ty(T), Offset(O), isArray(false) {}
134 bool operator<(const TypeRec &TR) const {
135 // Sort first by offset!
136 return Offset < TR.Offset || (Offset == TR.Offset && Ty < TR.Ty);
138 bool operator==(const TypeRec &TR) const {
139 return Ty == TR.Ty && Offset == TR.Offset;
141 bool operator!=(const TypeRec &TR) const { return !operator==(TR); }
144 /// TypeEntries - As part of the merging process of this algorithm, nodes of
145 /// different types can be represented by this single DSNode. This vector is
148 std::vector<TypeRec> TypeEntries;
150 /// Globals - The list of global values that are merged into this node.
152 std::vector<GlobalValue*> Globals;
154 void operator=(const DSNode &); // DO NOT IMPLEMENT
157 ShadowNode = 0, // Nothing is known about this node...
158 ScalarNode = 1 << 0, // Scalar of the current function contains this value
159 AllocaNode = 1 << 1, // This node was allocated with alloca
160 NewNode = 1 << 2, // This node was allocated with malloc
161 GlobalNode = 1 << 3, // This node was allocated by a global var decl
162 Incomplete = 1 << 4, // This node may not be complete
163 Modified = 1 << 5, // This node is modified in this context
164 Read = 1 << 6, // This node is read in this context
167 /// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
168 /// to the nodes in the data structure graph, so it is possible to have nodes
169 /// with a value of 0 for their NodeType. Scalar and Alloca markers go away
170 /// when function graphs are inlined.
172 unsigned char NodeType;
174 DSNode(enum NodeTy NT, const Type *T);
175 DSNode(const DSNode &);
179 dropAllReferences(); // Only needed to satisfy assertion checks...
180 assert(Referrers.empty() && "Referrers to dead node exist!");
184 // Iterator for graph interface...
185 typedef DSNodeIterator iterator;
186 typedef DSNodeIterator const_iterator;
187 inline iterator begin() const; // Defined in DSGraphTraits.h
188 inline iterator end() const;
190 //===--------------------------------------------------
193 /// getSize - Return the maximum number of bytes occupied by this object...
195 unsigned getSize() const { return MergeMap.size(); }
197 // getTypeEntries - Return the possible types and their offsets in this object
198 const std::vector<TypeRec> &getTypeEntries() const { return TypeEntries; }
200 /// getReferrers - Return a list of the pointers to this node...
202 const std::vector<DSNodeHandle*> &getReferrers() const { return Referrers; }
204 /// isModified - Return true if this node may be modified in this context
206 bool isModified() const { return (NodeType & Modified) != 0; }
208 /// isRead - Return true if this node may be read in this context
210 bool isRead() const { return (NodeType & Read) != 0; }
213 /// hasLink - Return true if this memory object has a link at the specified
216 bool hasLink(unsigned i) const {
217 assert(i < getSize() && "Field Link index is out of range!");
218 return MergeMap[i] >= 0;
221 DSNodeHandle *getLink(unsigned i) {
223 return &Links[MergeMap[i]];
226 const DSNodeHandle *getLink(unsigned i) const {
228 return &Links[MergeMap[i]];
232 int getMergeMapLabel(unsigned i) const {
233 assert(i < MergeMap.size() && "MergeMap index out of range!");
237 /// setLink - Set the link at the specified offset to the specified
238 /// NodeHandle, replacing what was there. It is uncommon to use this method,
239 /// instead one of the higher level methods should be used, below.
241 void setLink(unsigned i, const DSNodeHandle &NH);
243 /// addEdgeTo - Add an edge from the current node to the specified node. This
244 /// can cause merging of nodes in the graph.
246 void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
248 /// mergeWith - Merge this node and the specified node, moving all links to
249 /// and from the argument node into the current node, deleting the node
250 /// argument. Offset indicates what offset the specified node is to be merged
251 /// into the current node.
253 /// The specified node may be a null pointer (in which case, nothing happens).
255 void mergeWith(const DSNodeHandle &NH, unsigned Offset);
257 /// mergeIndexes - If we discover that two indexes are equivalent and must be
258 /// merged, this function is used to do the dirty work.
260 void mergeIndexes(unsigned idx1, unsigned idx2) {
261 assert(idx1 < getSize() && idx2 < getSize() && "Indexes out of range!");
262 signed char MV1 = MergeMap[idx1];
263 signed char MV2 = MergeMap[idx2];
265 mergeMappedValues(MV1, MV2);
269 /// addGlobal - Add an entry for a global value to the Globals list. This
270 /// also marks the node with the 'G' flag if it does not already have it.
272 void addGlobal(GlobalValue *GV);
273 const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
274 std::vector<GlobalValue*> &getGlobals() { return Globals; }
276 void print(std::ostream &O, const DSGraph *G) const;
279 void dropAllReferences() {
283 /// remapLinks - Change all of the Links in the current node according to the
284 /// specified mapping.
285 void remapLinks(std::map<const DSNode*, DSNode*> &OldNodeMap);
288 friend class DSNodeHandle;
289 // addReferrer - Keep the referrer set up to date...
290 void addReferrer(DSNodeHandle *H) { Referrers.push_back(H); }
291 void removeReferrer(DSNodeHandle *H);
293 /// rewriteMergeMap - Loop over the mergemap, replacing any references to the
294 /// index From to be references to the index To.
296 void rewriteMergeMap(signed char From, signed char To) {
297 assert(From != To && "Cannot change something into itself!");
298 for (unsigned i = 0, e = MergeMap.size(); i != e; ++i)
299 if (MergeMap[i] == From)
303 /// mergeMappedValues - This is the higher level form of rewriteMergeMap. It
304 /// is fully capable of merging links together if neccesary as well as simply
305 /// rewriting the map entries.
307 void mergeMappedValues(signed char V1, signed char V2);
311 //===----------------------------------------------------------------------===//
312 // Define inline DSNodeHandle functions that depend on the definition of DSNode
315 inline void DSNodeHandle::setNode(DSNode *n) {
316 if (N) N->removeReferrer(this);
318 if (N) N->addReferrer(this);
321 inline bool DSNodeHandle::hasLink(unsigned Num) const {
322 assert(N && "DSNodeHandle does not point to a node yet!");
323 return N->hasLink(Num+Offset);
327 /// getLink - Treat this current node pointer as a pointer to a structure of
328 /// some sort. This method will return the pointer a mem[this+Num]
330 inline const DSNodeHandle *DSNodeHandle::getLink(unsigned Num) const {
331 assert(N && "DSNodeHandle does not point to a node yet!");
332 return N->getLink(Num+Offset);
334 inline DSNodeHandle *DSNodeHandle::getLink(unsigned Num) {
335 assert(N && "DSNodeHandle does not point to a node yet!");
336 return N->getLink(Num+Offset);
339 inline void DSNodeHandle::setLink(unsigned Num, const DSNodeHandle &NH) {
340 assert(N && "DSNodeHandle does not point to a node yet!");
341 N->setLink(Num+Offset, NH);
344 /// addEdgeTo - Add an edge from the current node to the specified node. This
345 /// can cause merging of nodes in the graph.
347 inline void DSNodeHandle::addEdgeTo(unsigned LinkNo, const DSNodeHandle &Node) {
348 assert(N && "DSNodeHandle does not point to a node yet!");
349 N->addEdgeTo(LinkNo+Offset, Node);
352 /// mergeWith - Merge the logical node pointed to by 'this' with the node
353 /// pointed to by 'N'.
355 inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) {
356 assert(N && "DSNodeHandle does not point to a node yet!");
357 N->mergeWith(Node, Offset);
361 //===----------------------------------------------------------------------===//
362 /// DSCallSite - Representation of a call site via its call instruction,
363 /// the DSNode handle for the callee function (or function pointer), and
364 /// the DSNode handles for the function arguments.
366 /// One unusual aspect of this callsite record is the ResolvingCaller member.
367 /// If this is non-null, then it indicates the function that allowed a call-site
368 /// to finally be resolved. Because of indirect calls, this function may not
369 /// actually be the function that contains the Call instruction itself. This is
370 /// used by the BU and TD passes to communicate.
373 CallInst *Inst; // Actual call site
374 DSNodeHandle RetVal; // Returned value
375 DSNodeHandle Callee; // The function node called
376 std::vector<DSNodeHandle> CallArgs; // The pointer arguments
377 Function *ResolvingCaller; // See comments above
379 static void InitNH(DSNodeHandle &NH, const DSNodeHandle &Src,
380 const std::map<const DSNode*, DSNode*> &NodeMap) {
381 if (DSNode *N = Src.getNode()) {
382 std::map<const DSNode*, DSNode*>::const_iterator I = NodeMap.find(N);
383 assert(I != NodeMap.end() && "Not not in mapping!");
385 NH.setOffset(Src.getOffset());
386 NH.setNode(I->second);
390 static void InitNH(DSNodeHandle &NH, const DSNodeHandle &Src,
391 const std::map<const DSNode*, DSNodeHandle> &NodeMap) {
392 if (DSNode *N = Src.getNode()) {
393 std::map<const DSNode*, DSNodeHandle>::const_iterator I = NodeMap.find(N);
394 assert(I != NodeMap.end() && "Not not in mapping!");
396 NH.setOffset(Src.getOffset()+I->second.getOffset());
397 NH.setNode(I->second.getNode());
401 DSCallSite(); // DO NOT IMPLEMENT
403 /// Constructor. Note - This ctor destroys the argument vector passed in. On
404 /// exit, the argument vector is empty.
406 DSCallSite(CallInst &inst, const DSNodeHandle &rv, const DSNodeHandle &callee,
407 std::vector<DSNodeHandle> &Args)
408 : Inst(&inst), RetVal(rv), Callee(callee), ResolvingCaller(0) {
412 DSCallSite(const DSCallSite &DSCS) // Simple copy ctor
413 : Inst(DSCS.Inst), RetVal(DSCS.RetVal),
414 Callee(DSCS.Callee), CallArgs(DSCS.CallArgs),
415 ResolvingCaller(DSCS.ResolvingCaller) {}
417 /// Mapping copy constructor - This constructor takes a preexisting call site
418 /// to copy plus a map that specifies how the links should be transformed.
419 /// This is useful when moving a call site from one graph to another.
421 template<typename MapTy>
422 DSCallSite(const DSCallSite &FromCall, const MapTy &NodeMap) {
423 Inst = FromCall.Inst;
424 InitNH(RetVal, FromCall.RetVal, NodeMap);
425 InitNH(Callee, FromCall.Callee, NodeMap);
427 CallArgs.resize(FromCall.CallArgs.size());
428 for (unsigned i = 0, e = FromCall.CallArgs.size(); i != e; ++i)
429 InitNH(CallArgs[i], FromCall.CallArgs[i], NodeMap);
430 ResolvingCaller = FromCall.ResolvingCaller;
433 // Accessor functions...
434 Function &getCaller() const;
435 CallInst &getCallInst() const { return *Inst; }
436 DSNodeHandle &getRetVal() { return RetVal; }
437 DSNodeHandle &getCallee() { return Callee; }
438 const DSNodeHandle &getRetVal() const { return RetVal; }
439 const DSNodeHandle &getCallee() const { return Callee; }
440 void setCallee(const DSNodeHandle &H) { Callee = H; }
442 unsigned getNumPtrArgs() const { return CallArgs.size(); }
444 Function *getResolvingCaller() const { return ResolvingCaller; }
445 void setResolvingCaller(Function *F) { ResolvingCaller = F; }
447 DSNodeHandle &getPtrArg(unsigned i) {
448 assert(i < CallArgs.size() && "Argument to getPtrArgNode is out of range!");
451 const DSNodeHandle &getPtrArg(unsigned i) const {
452 assert(i < CallArgs.size() && "Argument to getPtrArgNode is out of range!");
456 bool operator<(const DSCallSite &CS) const {
457 if (RetVal < CS.RetVal) return true;
458 if (RetVal > CS.RetVal) return false;
459 if (Callee < CS.Callee) return true;
460 if (Callee > CS.Callee) return false;
461 return CallArgs < CS.CallArgs;
464 bool operator==(const DSCallSite &CS) const {
465 return RetVal == CS.RetVal && Callee == CS.Callee &&
466 CallArgs == CS.CallArgs;
471 //===----------------------------------------------------------------------===//
472 /// DSGraph - The graph that represents a function.
476 std::vector<DSNode*> Nodes;
477 DSNodeHandle RetNode; // Node that gets returned...
478 std::map<Value*, DSNodeHandle> ValueMap;
481 // GlobalsGraph -- Reference to the common graph of globally visible objects.
482 // This includes GlobalValues, New nodes, Cast nodes, and Calls.
484 GlobalDSGraph* GlobalsGraph;
487 // FunctionCalls - This vector maintains a single entry for each call
488 // instruction in the current graph. Each call entry contains DSNodeHandles
489 // that refer to the arguments that are passed into the function call. The
490 // first entry in the vector is the scalar that holds the return value for the
491 // call, the second is the function scalar being invoked, and the rest are
492 // pointer arguments to the function.
494 std::vector<DSCallSite> FunctionCalls;
496 void operator=(const DSGraph &); // DO NOT IMPLEMENT
498 DSGraph() : Func(0) {} // Create a new, empty, DSGraph.
499 DSGraph(Function &F); // Compute the local DSGraph
501 // Copy ctor - If you want to capture the node mapping between the source and
502 // destination graph, you may optionally do this by specifying a map to record
504 DSGraph(const DSGraph &DSG);
505 DSGraph(const DSGraph &DSG, std::map<const DSNode*, DSNode*> &BUNodeMap);
508 bool hasFunction() const { return Func != 0; }
509 Function &getFunction() const { return *Func; }
511 /// getNodes - Get a vector of all the nodes in the graph
513 const std::vector<DSNode*> &getNodes() const { return Nodes; }
514 std::vector<DSNode*> &getNodes() { return Nodes; }
516 /// addNode - Add a new node to the graph.
518 void addNode(DSNode *N) { Nodes.push_back(N); }
520 /// getValueMap - Get a map that describes what the nodes the scalars in this
521 /// function point to...
523 std::map<Value*, DSNodeHandle> &getValueMap() { return ValueMap; }
524 const std::map<Value*, DSNodeHandle> &getValueMap() const { return ValueMap;}
526 std::vector<DSCallSite> &getFunctionCalls() {
527 return FunctionCalls;
529 const std::vector<DSCallSite> &getFunctionCalls() const {
530 return FunctionCalls;
533 /// getNodeForValue - Given a value that is used or defined in the body of the
534 /// current function, return the DSNode that it points to.
536 DSNodeHandle &getNodeForValue(Value *V) { return ValueMap[V]; }
538 const DSNodeHandle &getRetNode() const { return RetNode; }
539 DSNodeHandle &getRetNode() { return RetNode; }
541 unsigned getGraphSize() const {
545 void print(std::ostream &O) const;
547 void writeGraphToFile(std::ostream &O, const std::string &GraphName) const;
549 // maskNodeTypes - Apply a mask to all of the node types in the graph. This
550 // is useful for clearing out markers like Scalar or Incomplete.
552 void maskNodeTypes(unsigned char Mask);
553 void maskIncompleteMarkers() { maskNodeTypes(~DSNode::Incomplete); }
555 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
556 // modified by other functions that have not been resolved yet. This marks
557 // nodes that are reachable through three sources of "unknownness":
558 // Global Variables, Function Calls, and Incoming Arguments
560 // For any node that may have unknown components (because something outside
561 // the scope of current analysis may have modified it), the 'Incomplete' flag
562 // is added to the NodeType.
564 void markIncompleteNodes(bool markFormalArgs = true);
566 // removeTriviallyDeadNodes - After the graph has been constructed, this
567 // method removes all unreachable nodes that are created because they got
568 // merged with other nodes in the graph.
570 void removeTriviallyDeadNodes(bool KeepAllGlobals = false);
572 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
573 // subgraphs that are unreachable. This often occurs because the data
574 // structure doesn't "escape" into it's caller, and thus should be eliminated
575 // from the caller's graph entirely. This is only appropriate to use when
578 void removeDeadNodes(bool KeepAllGlobals = false, bool KeepCalls = true);
580 // cloneInto - Clone the specified DSGraph into the current graph, returning
581 // the Return node of the graph. The translated ValueMap for the old function
582 // is filled into the OldValMap member.
583 // If StripScalars (StripAllocas) is set to true, Scalar (Alloca) markers
584 // are removed from the graph as the graph is being cloned.
586 DSNodeHandle cloneInto(const DSGraph &G,
587 std::map<Value*, DSNodeHandle> &OldValMap,
588 std::map<const DSNode*, DSNode*> &OldNodeMap,
589 bool StripScalars = false, bool StripAllocas = false);
592 // cloneGlobalInto - Clone the given global node (or the node for the given
593 // GlobalValue) from the GlobalsGraph and all its target links (recursively).
595 DSNode* cloneGlobalInto(const DSNode* GNode);
596 DSNode* cloneGlobalInto(GlobalValue* GV) {
597 assert(!GV || (((DSGraph*) GlobalsGraph)->ValueMap[GV] != 0));
598 return GV? cloneGlobalInto(((DSGraph*) GlobalsGraph)->ValueMap[GV]) : 0;
603 bool isNodeDead(DSNode *N);