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
11 #include "llvm/Pass.h"
16 class DSNode; // Each node in the graph
17 class DSGraph; // A graph for a function
18 class DSNodeIterator; // Data structure graph traversal iterator
20 //===----------------------------------------------------------------------===//
21 /// DSNodeHandle - Implement a "handle" to a data structure node that takes care
22 /// of all of the add/un'refing of the node to prevent the backpointers in the
23 /// graph from getting out of date. This class represents a "pointer" in the
24 /// graph, whose destination is an indexed offset into a node.
30 // Allow construction, destruction, and assignment...
31 DSNodeHandle(DSNode *n = 0, unsigned offs = 0) : N(0), Offset(offs) {
34 DSNodeHandle(const DSNodeHandle &H) : N(0), Offset(H.Offset) { setNode(H.N); }
35 ~DSNodeHandle() { setNode((DSNode*)0); }
36 DSNodeHandle &operator=(const DSNodeHandle &H) {
37 setNode(H.N); Offset = H.Offset;
41 bool operator<(const DSNodeHandle &H) const { // Allow sorting
42 return N < H.N || (N == H.N && Offset < H.Offset);
44 bool operator==(const DSNodeHandle &H) const { // Allow comparison
45 return N == H.N && Offset == H.Offset;
47 bool operator!=(const DSNodeHandle &H) const { return !operator==(H); }
49 // Allow explicit conversion to DSNode...
50 DSNode *getNode() const { return N; }
51 unsigned getOffset() const { return Offset; }
53 inline void setNode(DSNode *N); // Defined inline later...
54 void setOffset(unsigned O) { Offset = O; }
56 void addEdgeTo(unsigned LinkNo, const DSNodeHandle &N);
57 void addEdgeTo(const DSNodeHandle &N) { addEdgeTo(0, N); }
59 /// mergeWith - Merge the logical node pointed to by 'this' with the node
60 /// pointed to by 'N'.
62 void mergeWith(const DSNodeHandle &N);
64 // hasLink - Return true if there is a link at the specified offset...
65 inline bool hasLink(unsigned Num) const;
67 /// getLink - Treat this current node pointer as a pointer to a structure of
68 /// some sort. This method will return the pointer a mem[this+Num]
70 inline const DSNodeHandle *getLink(unsigned Num) const;
71 inline DSNodeHandle *getLink(unsigned Num);
73 inline void setLink(unsigned Num, const DSNodeHandle &NH);
77 //===----------------------------------------------------------------------===//
78 /// DSNode - Data structure node class
80 /// This class represents an untyped memory object of Size bytes. It keeps
81 /// track of any pointers that have been stored into the object as well as the
82 /// different types represented in this object.
85 /// Links - Contains one entry for every _distinct_ pointer field in the
86 /// memory block. These are demand allocated and indexed by the MergeMap
89 std::vector<DSNodeHandle> Links;
91 /// MergeMap - Maps from every byte in the object to a signed byte number.
92 /// This map is neccesary due to the merging that is possible as part of the
93 /// unification algorithm. To merge two distinct bytes of the object together
94 /// into a single logical byte, the indexes for the two bytes are set to the
95 /// same value. This fully general merging is capable of representing all
96 /// manners of array merging if neccesary.
98 /// This map is also used to map outgoing pointers to various byte offsets in
99 /// this data structure node. If this value is >= 0, then it indicates that
100 /// the numbered entry in the Links vector contains the outgoing edge for this
101 /// byte offset. In this way, the Links vector can be demand allocated and
102 /// byte elements of the node may be merged without needing a Link allocated
105 /// Initially, each each element of the MergeMap is assigned a unique negative
106 /// number, which are then merged as the unification occurs.
108 std::vector<signed char> MergeMap;
110 /// Referrers - Keep track of all of the node handles that point to this
111 /// DSNode. These pointers may need to be updated to point to a different
112 /// node if this node gets merged with it.
114 std::vector<DSNodeHandle*> Referrers;
116 /// TypeEntries - As part of the merging process of this algorithm, nodes of
117 /// different types can be represented by this single DSNode. This vector is
120 typedef std::pair<const Type *, unsigned> TypeRec;
121 std::vector<TypeRec> TypeEntries;
123 /// Globals - The list of global values that are merged into this node.
125 std::vector<GlobalValue*> Globals;
127 void operator=(const DSNode &); // DO NOT IMPLEMENT
130 ShadowNode = 0, // Nothing is known about this node...
131 ScalarNode = 1 << 0, // Scalar of the current function contains this value
132 AllocaNode = 1 << 1, // This node was allocated with alloca
133 NewNode = 1 << 2, // This node was allocated with malloc
134 GlobalNode = 1 << 3, // This node was allocated by a global var decl
135 Incomplete = 1 << 4, // This node may not be complete
138 /// NodeType - A union of the above bits. "Shadow" nodes do not add any flags
139 /// to the nodes in the data structure graph, so it is possible to have nodes
140 /// with a value of 0 for their NodeType. Scalar and Alloca markers go away
141 /// when function graphs are inlined.
143 unsigned char NodeType;
145 DSNode(enum NodeTy NT, const Type *T);
146 DSNode(const DSNode &);
150 dropAllReferences(); // Only needed to satisfy assertion checks...
151 assert(Referrers.empty() && "Referrers to dead node exist!");
155 // Iterator for graph interface...
156 typedef DSNodeIterator iterator;
157 inline iterator begin(); // Defined in DataStructureGraph.h
158 inline iterator end();
160 //===--------------------------------------------------
163 // getSize - Return the maximum number of bytes occupied by this object...
164 unsigned getSize() const { return MergeMap.size(); }
166 // getTypeEntries - Return the possible types and their offsets in this object
167 const std::vector<TypeRec> &getTypeEntries() const { return TypeEntries; }
169 // getReferrers - Return a list of the pointers to this node...
170 const std::vector<DSNodeHandle*> &getReferrers() const { return Referrers; }
173 /// hasLink - Return true if this memory object has a link at the specified
176 bool hasLink(unsigned i) const {
177 assert(i < getSize() && "Field Link index is out of range!");
178 return MergeMap[i] >= 0;
181 DSNodeHandle *getLink(unsigned i) {
183 return &Links[MergeMap[i]];
186 const DSNodeHandle *getLink(unsigned i) const {
188 return &Links[MergeMap[i]];
192 /// setLink - Set the link at the specified offset to the specified
193 /// NodeHandle, replacing what was there. It is uncommon to use this method,
194 /// instead one of the higher level methods should be used, below.
196 void setLink(unsigned i, const DSNodeHandle &NH);
198 /// addEdgeTo - Add an edge from the current node to the specified node. This
199 /// can cause merging of nodes in the graph.
201 void addEdgeTo(unsigned Offset, const DSNodeHandle &NH);
203 /// mergeWith - Merge this node and the specified node, moving all links to
204 /// and from the argument node into the current node, deleting the node
205 /// argument. Offset indicates what offset the specified node is to be merged
206 /// into the current node.
208 /// The specified node may be a null pointer (in which case, nothing happens).
210 void mergeWith(const DSNodeHandle &NH, unsigned Offset);
212 /// addGlobal - Add an entry for a global value to the Globals list. This
213 /// also marks the node with the 'G' flag if it does not already have it.
215 void addGlobal(GlobalValue *GV);
216 const std::vector<GlobalValue*> &getGlobals() const { return Globals; }
217 std::vector<GlobalValue*> &getGlobals() { return Globals; }
219 void print(std::ostream &O, const DSGraph *G) const;
222 void dropAllReferences() {
226 /// remapLinks - Change all of the Links in the current node according to the
227 /// specified mapping.
228 void remapLinks(std::map<const DSNode*, DSNode*> &OldNodeMap);
231 friend class DSNodeHandle;
232 // addReferrer - Keep the referrer set up to date...
233 void addReferrer(DSNodeHandle *H) { Referrers.push_back(H); }
234 void removeReferrer(DSNodeHandle *H);
236 /// rewriteMergeMap - Loop over the mergemap, replacing any references to the
237 /// index From to be references to the index To.
239 void rewriteMergeMap(signed char From, signed char To) {
240 assert(From != To && "Cannot change something into itself!");
241 for (unsigned i = 0, e = MergeMap.size(); i != e; ++i)
242 if (MergeMap[i] == From)
246 /// mergeMappedValues - This is the higher level form of rewriteMergeMap. It
247 /// is fully capable of merging links together if neccesary as well as simply
248 /// rewriting the map entries.
250 void mergeMappedValues(signed char V1, signed char V2);
254 //===----------------------------------------------------------------------===//
255 // Define inline DSNodeHandle functions that depend on the definition of DSNode
258 inline void DSNodeHandle::setNode(DSNode *n) {
259 if (N) N->removeReferrer(this);
261 if (N) N->addReferrer(this);
264 inline bool DSNodeHandle::hasLink(unsigned Num) const {
265 assert(N && "DSNodeHandle does not point to a node yet!");
266 return N->hasLink(Num+Offset);
270 /// getLink - Treat this current node pointer as a pointer to a structure of
271 /// some sort. This method will return the pointer a mem[this+Num]
273 inline const DSNodeHandle *DSNodeHandle::getLink(unsigned Num) const {
274 assert(N && "DSNodeHandle does not point to a node yet!");
275 return N->getLink(Num+Offset);
277 inline DSNodeHandle *DSNodeHandle::getLink(unsigned Num) {
278 assert(N && "DSNodeHandle does not point to a node yet!");
279 return N->getLink(Num+Offset);
282 inline void DSNodeHandle::setLink(unsigned Num, const DSNodeHandle &NH) {
283 assert(N && "DSNodeHandle does not point to a node yet!");
284 N->setLink(Num+Offset, NH);
287 /// addEdgeTo - Add an edge from the current node to the specified node. This
288 /// can cause merging of nodes in the graph.
290 inline void DSNodeHandle::addEdgeTo(unsigned LinkNo, const DSNodeHandle &Node) {
291 assert(N && "DSNodeHandle does not point to a node yet!");
292 N->addEdgeTo(LinkNo+Offset, Node);
295 /// mergeWith - Merge the logical node pointed to by 'this' with the node
296 /// pointed to by 'N'.
298 inline void DSNodeHandle::mergeWith(const DSNodeHandle &Node) {
299 assert(N && "DSNodeHandle does not point to a node yet!");
300 N->mergeWith(Node, Offset);
304 //===----------------------------------------------------------------------===//
305 /// DSGraph - The graph that represents a function.
309 std::vector<DSNode*> Nodes;
310 DSNodeHandle RetNode; // Node that gets returned...
311 std::map<Value*, DSNodeHandle> ValueMap;
314 // GlobalsGraph -- Reference to the common graph of globally visible objects.
315 // This includes GlobalValues, New nodes, Cast nodes, and Calls.
317 GlobalDSGraph* GlobalsGraph;
320 // FunctionCalls - This vector maintains a single entry for each call
321 // instruction in the current graph. Each call entry contains DSNodeHandles
322 // that refer to the arguments that are passed into the function call. The
323 // first entry in the vector is the scalar that holds the return value for the
324 // call, the second is the function scalar being invoked, and the rest are
325 // pointer arguments to the function.
327 std::vector<std::vector<DSNodeHandle> > FunctionCalls;
330 // OrigFunctionCalls - This vector retains a copy of the original function
331 // calls of the current graph. This is needed to support top-down inlining
332 // after bottom-up inlining is complete, since the latter deletes call nodes.
334 std::vector<std::vector<DSNodeHandle> > OrigFunctionCalls;
336 // PendingCallers - This vector records all unresolved callers of the
337 // current function, i.e., ones whose graphs have not been inlined into
338 // the current graph. As long as there are unresolved callers, the nodes
339 // for formal arguments in the current graph cannot be eliminated, and
340 // nodes in the graph reachable from the formal argument nodes or
341 // global variable nodes must be considered incomplete.
342 std::set<Function*> PendingCallers;
348 // clone all the call nodes and save the copies in OrigFunctionCalls
349 void saveOrigFunctionCalls() {
350 assert(OrigFunctionCalls.size() == 0 && "Do this only once!");
351 OrigFunctionCalls = FunctionCalls;
354 // get the saved copies of the original function call nodes
355 std::vector<std::vector<DSNodeHandle> > &getOrigFunctionCalls() {
356 return OrigFunctionCalls;
360 void operator=(const DSGraph &); // DO NOT IMPLEMENT
362 DSGraph() : Func(0) {} // Create a new, empty, DSGraph.
363 DSGraph(Function &F); // Compute the local DSGraph
364 DSGraph(const DSGraph &DSG); // Copy ctor
367 bool hasFunction() const { return Func != 0; }
368 Function &getFunction() const { return *Func; }
370 /// getNodes - Get a vector of all the nodes in the graph
372 const std::vector<DSNode*> &getNodes() const { return Nodes; }
373 std::vector<DSNode*> &getNodes() { return Nodes; }
375 /// addNode - Add a new node to the graph.
377 void addNode(DSNode *N) { Nodes.push_back(N); }
379 /// getValueMap - Get a map that describes what the nodes the scalars in this
380 /// function point to...
382 std::map<Value*, DSNodeHandle> &getValueMap() { return ValueMap; }
383 const std::map<Value*, DSNodeHandle> &getValueMap() const { return ValueMap;}
385 std::vector<std::vector<DSNodeHandle> > &getFunctionCalls() {
386 return FunctionCalls;
388 const std::vector<std::vector<DSNodeHandle> > &getFunctionCalls() const {
389 return FunctionCalls;
392 const DSNodeHandle &getRetNode() const { return RetNode; }
393 DSNodeHandle &getRetNode() { return RetNode; }
395 unsigned getGraphSize() const {
399 void print(std::ostream &O) const;
401 void writeGraphToFile(std::ostream &O, const std::string &GraphName);
403 // maskNodeTypes - Apply a mask to all of the node types in the graph. This
404 // is useful for clearing out markers like Scalar or Incomplete.
406 void maskNodeTypes(unsigned char Mask);
407 void maskIncompleteMarkers() { maskNodeTypes(~DSNode::Incomplete); }
409 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
410 // modified by other functions that have not been resolved yet. This marks
411 // nodes that are reachable through three sources of "unknownness":
412 // Global Variables, Function Calls, and Incoming Arguments
414 // For any node that may have unknown components (because something outside
415 // the scope of current analysis may have modified it), the 'Incomplete' flag
416 // is added to the NodeType.
418 void markIncompleteNodes(bool markFormalArgs = true);
420 // removeTriviallyDeadNodes - After the graph has been constructed, this
421 // method removes all unreachable nodes that are created because they got
422 // merged with other nodes in the graph.
424 void removeTriviallyDeadNodes(bool KeepAllGlobals = false);
426 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
427 // subgraphs that are unreachable. This often occurs because the data
428 // structure doesn't "escape" into it's caller, and thus should be eliminated
429 // from the caller's graph entirely. This is only appropriate to use when
432 void removeDeadNodes(bool KeepAllGlobals = false, bool KeepCalls = true);
435 // AddCaller - add a known caller node into the graph and mark it pending.
436 // getCallers - get a vector of the functions that call this one
437 // getCallersPending - get a matching vector of bools indicating if each
438 // caller's DSGraph has been resolved into this one.
440 void addCaller(Function &caller) {
441 PendingCallers.insert(&caller);
443 std::set<Function*> &getPendingCallers() {
444 return PendingCallers;
448 // cloneInto - Clone the specified DSGraph into the current graph, returning
449 // the Return node of the graph. The translated ValueMap for the old function
450 // is filled into the OldValMap member.
451 // If StripScalars (StripAllocas) is set to true, Scalar (Alloca) markers
452 // are removed from the graph as the graph is being cloned.
453 // If CopyCallers is set to true, the PendingCallers list is copied.
454 // If CopyOrigCalls is set to true, the OrigFunctionCalls list is copied.
456 DSNodeHandle cloneInto(const DSGraph &G,
457 std::map<Value*, DSNodeHandle> &OldValMap,
458 std::map<const DSNode*, DSNode*> &OldNodeMap,
459 bool StripScalars = false, bool StripAllocas = false,
460 bool CopyCallers = true, bool CopyOrigCalls = true);
463 // cloneGlobalInto - Clone the given global node (or the node for the given
464 // GlobalValue) from the GlobalsGraph and all its target links (recursively).
466 DSNode* cloneGlobalInto(const DSNode* GNode);
467 DSNode* cloneGlobalInto(GlobalValue* GV) {
468 assert(!GV || (((DSGraph*) GlobalsGraph)->ValueMap[GV] != 0));
469 return GV? cloneGlobalInto(((DSGraph*) GlobalsGraph)->ValueMap[GV]) : 0;
474 bool isNodeDead(DSNode *N);