1 //===- DataStructure.cpp - Implement the core data structure analysis -----===//
3 // This file implements the core data structure functionality.
5 //===----------------------------------------------------------------------===//
7 #include "llvm/Analysis/DSGraph.h"
8 #include "llvm/Function.h"
9 #include "llvm/iOther.h"
10 #include "llvm/DerivedTypes.h"
11 #include "llvm/Target/TargetData.h"
12 #include "Support/STLExtras.h"
13 #include "Support/Statistic.h"
20 namespace DataStructureAnalysis {
21 // isPointerType - Return true if this first class type is big enough to hold
24 bool isPointerType(const Type *Ty);
27 using namespace DataStructureAnalysis;
29 //===----------------------------------------------------------------------===//
30 // DSNode Implementation
31 //===----------------------------------------------------------------------===//
33 DSNode::DSNode(enum NodeTy NT, const Type *T) : NodeType(NT) {
34 // If this node is big enough to have pointer fields, add space for them now.
35 if (T != Type::VoidTy && !isa<FunctionType>(T)) { // Avoid TargetData assert's
36 MergeMap.resize(TD.getTypeSize(T));
38 // Assign unique values to all of the elements of MergeMap
39 if (MergeMap.size() < 128) {
40 // Handle the common case of reasonable size structures...
41 for (unsigned i = 0, e = MergeMap.size(); i != e; ++i)
42 MergeMap[i] = -1-i; // Assign -1, -2, -3, ...
44 // It's possible that we have something really big here. In this case,
45 // divide the object into chunks until it will fit into 128 elements.
46 unsigned Multiple = MergeMap.size()/128;
48 // It's probably an array, and probably some power of two in size.
49 // Because of this, find the biggest power of two that is bigger than
50 // multiple to use as our real Multiple.
51 unsigned RealMultiple = 2;
52 while (RealMultiple <= Multiple) RealMultiple <<= 1;
54 unsigned RealBound = MergeMap.size()/RealMultiple;
55 assert(RealBound <= 128 && "Math didn't work out right");
57 // Now go through and assign indexes that are between -1 and -128
60 for (unsigned i = 0, e = MergeMap.size(); i != e; ++i)
61 MergeMap[i] = -1-(i % RealBound); // Assign -1, -2, -3...
65 TypeEntries.push_back(TypeRec(T, 0));
68 // DSNode copy constructor... do not copy over the referrers list!
69 DSNode::DSNode(const DSNode &N)
70 : Links(N.Links), MergeMap(N.MergeMap),
71 TypeEntries(N.TypeEntries), Globals(N.Globals), NodeType(N.NodeType) {
74 void DSNode::removeReferrer(DSNodeHandle *H) {
75 // Search backwards, because we depopulate the list from the back for
76 // efficiency (because it's a vector).
77 vector<DSNodeHandle*>::reverse_iterator I =
78 std::find(Referrers.rbegin(), Referrers.rend(), H);
79 assert(I != Referrers.rend() && "Referrer not pointing to node!");
80 Referrers.erase(I.base()-1);
83 // addGlobal - Add an entry for a global value to the Globals list. This also
84 // marks the node with the 'G' flag if it does not already have it.
86 void DSNode::addGlobal(GlobalValue *GV) {
87 // Keep the list sorted.
88 vector<GlobalValue*>::iterator I =
89 std::lower_bound(Globals.begin(), Globals.end(), GV);
91 if (I == Globals.end() || *I != GV) {
92 //assert(GV->getType()->getElementType() == Ty);
93 Globals.insert(I, GV);
94 NodeType |= GlobalNode;
99 /// setLink - Set the link at the specified offset to the specified
100 /// NodeHandle, replacing what was there. It is uncommon to use this method,
101 /// instead one of the higher level methods should be used, below.
103 void DSNode::setLink(unsigned i, const DSNodeHandle &NH) {
104 // Create a new entry in the Links vector to hold a new element for offset.
106 signed char NewIdx = Links.size();
107 // Check to see if we allocate more than 128 distinct links for this node.
108 // If so, just merge with the last one. This really shouldn't ever happen,
109 // but it should work regardless of whether it does or not.
112 Links.push_back(NH); // Allocate space: common case
113 } else { // Wrap around? Too many links?
114 NewIdx--; // Merge with whatever happened last
115 assert(NewIdx > 0 && "Should wrap back around");
116 std::cerr << "\n*** DSNode found that requires more than 128 "
117 << "active links at once!\n\n";
120 signed char OldIdx = MergeMap[i];
121 assert (OldIdx < 0 && "Shouldn't contain link!");
123 // Make sure that anything aliasing this field gets updated to point to the
125 rewriteMergeMap(OldIdx, NewIdx);
126 assert(MergeMap[i] == NewIdx && "Field not replaced!");
128 Links[MergeMap[i]] = NH;
132 // addEdgeTo - Add an edge from the current node to the specified node. This
133 // can cause merging of nodes in the graph.
135 void DSNode::addEdgeTo(unsigned Offset, const DSNodeHandle &NH) {
136 assert(Offset < getSize() && "Offset out of range!");
137 if (NH.getNode() == 0) return; // Nothing to do
139 if (DSNodeHandle *ExistingNH = getLink(Offset)) {
140 // Merge the two nodes...
141 ExistingNH->mergeWith(NH);
142 } else { // No merging to perform...
143 setLink(Offset, NH); // Just force a link in there...
147 /// mergeMappedValues - This is the higher level form of rewriteMergeMap. It is
148 /// fully capable of merging links together if neccesary as well as simply
149 /// rewriting the map entries.
151 void DSNode::mergeMappedValues(signed char V1, signed char V2) {
152 assert(V1 != V2 && "Cannot merge two identical mapped values!");
154 if (V1 < 0) { // If there is no outgoing link from V1, merge it with V2
155 if (V2 < 0 && V1 > V2)
156 // If both are not linked, merge to the field closer to 0
157 rewriteMergeMap(V2, V1);
159 rewriteMergeMap(V1, V2);
160 } else if (V2 < 0) { // Is V2 < 0 && V1 >= 0?
161 rewriteMergeMap(V2, V1); // Merge into the one with the link...
162 } else { // Otherwise, links exist at both locations
163 // Merge Links[V1] with Links[V2] so they point to the same place now...
164 Links[V1].mergeWith(Links[V2]);
166 // Merge the V2 link into V1 so that we reduce the overall value of the
167 // links are reduced...
169 if (V2 < V1) std::swap(V1, V2); // Ensure V1 < V2
170 rewriteMergeMap(V2, V1); // After this, V2 is "dead"
172 // Change the user of the last link to use V2 instead
173 if ((unsigned)V2 != Links.size()-1) {
174 rewriteMergeMap(Links.size()-1, V2); // Point to V2 instead of last el...
175 // Make sure V2 points the right DSNode
176 Links[V2] = Links.back();
179 // Reduce the number of distinct outgoing links...
185 // MergeSortedVectors - Efficiently merge a vector into another vector where
186 // duplicates are not allowed and both are sorted. This assumes that 'T's are
187 // efficiently copyable and have sane comparison semantics.
190 void MergeSortedVectors(vector<T> &Dest, const vector<T> &Src) {
191 // By far, the most common cases will be the simple ones. In these cases,
192 // avoid having to allocate a temporary vector...
194 if (Src.empty()) { // Nothing to merge in...
196 } else if (Dest.empty()) { // Just copy the result in...
198 } else if (Src.size() == 1) { // Insert a single element...
200 typename vector<T>::iterator I =
201 std::lower_bound(Dest.begin(), Dest.end(), V);
202 if (I == Dest.end() || *I != Src[0]) // If not already contained...
203 Dest.insert(I, Src[0]);
204 } else if (Dest.size() == 1) {
205 T Tmp = Dest[0]; // Save value in temporary...
206 Dest = Src; // Copy over list...
207 typename vector<T>::iterator I =
208 std::lower_bound(Dest.begin(), Dest.end(),Tmp);
209 if (I == Dest.end() || *I != Src[0]) // If not already contained...
210 Dest.insert(I, Src[0]);
213 // Make a copy to the side of Dest...
216 // Make space for all of the type entries now...
217 Dest.resize(Dest.size()+Src.size());
219 // Merge the two sorted ranges together... into Dest.
220 std::merge(Old.begin(), Old.end(), Src.begin(), Src.end(), Dest.begin());
222 // Now erase any duplicate entries that may have accumulated into the
223 // vectors (because they were in both of the input sets)
224 Dest.erase(std::unique(Dest.begin(), Dest.end()), Dest.end());
229 // mergeWith - Merge this node and the specified node, moving all links to and
230 // from the argument node into the current node, deleting the node argument.
231 // Offset indicates what offset the specified node is to be merged into the
234 // The specified node may be a null pointer (in which case, nothing happens).
236 void DSNode::mergeWith(const DSNodeHandle &NH, unsigned Offset) {
237 DSNode *N = NH.getNode();
238 if (N == 0 || (N == this && NH.getOffset() == Offset))
241 assert(NH.getNode() != this &&
242 "Cannot merge two portions of the same node yet!");
244 // If both nodes are not at offset 0, make sure that we are merging the node
245 // at an later offset into the node with the zero offset.
247 if (Offset > NH.getOffset()) {
248 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
253 std::cerr << "\n\nMerging:\n";
254 N->print(std::cerr, 0);
255 std::cerr << " and:\n";
259 // Now we know that Offset <= NH.Offset, so convert it so our "Offset" (with
260 // respect to NH.Offset) is now zero.
262 unsigned NOffset = NH.getOffset()-Offset;
264 unsigned NSize = N->getSize();
265 assert(NSize+NOffset <= getSize() &&
266 "Don't know how to merge extend a merged nodes size yet!");
268 // Remove all edges pointing at N, causing them to point to 'this' instead.
269 // Make sure to adjust their offset, not just the node pointer.
271 while (!N->Referrers.empty()) {
272 DSNodeHandle &Ref = *N->Referrers.back();
273 Ref = DSNodeHandle(this, NOffset+Ref.getOffset());
276 // We must merge fields in this node due to nodes merged in the source node.
277 // In order to handle this we build a map that converts from the source node's
278 // MergeMap values to our MergeMap values. This map is indexed by the
279 // expression: MergeMap[SMM+SourceNodeSize] so we need to allocate at least
280 // 2*SourceNodeSize elements of space for the mapping. We can do this because
281 // we know that there are at most SourceNodeSize outgoing links in the node
282 // (thus that many positive values) and at most SourceNodeSize distinct fields
283 // (thus that many negative values).
285 std::vector<signed char> MergeMapMap(NSize*2, 127);
287 // Loop through the structures, merging them together...
288 for (unsigned i = 0, e = NSize; i != e; ++i) {
289 // Get what this byte of N maps to...
290 signed char NElement = N->MergeMap[i];
292 // Get what we map this byte to...
293 signed char Element = MergeMap[i+NOffset];
294 // We use 127 as a sentinal and don't check for it's existence yet...
295 assert(Element != 127 && "MergeMapMap doesn't permit 127 values yet!");
297 signed char CurMappedVal = MergeMapMap[NElement+NSize];
298 if (CurMappedVal == 127) { // Haven't seen this NElement yet?
299 MergeMapMap[NElement+NSize] = Element; // Map the two together...
300 } else if (CurMappedVal != Element) {
301 // If we are mapping two different fields together this means that we need
302 // to merge fields in the current node due to merging in the source node.
304 mergeMappedValues(CurMappedVal, Element);
305 MergeMapMap[NElement+NSize] = MergeMap[i+NOffset];
309 // Make all of the outgoing links of N now be outgoing links of this. This
310 // can cause recursive merging!
312 for (unsigned i = 0, e = NSize; i != e; ++i)
313 if (DSNodeHandle *Link = N->getLink(i)) {
314 addEdgeTo(i+NOffset, *Link);
315 N->MergeMap[i] = -1; // Kill outgoing edge
318 // Now that there are no outgoing edges, all of the Links are dead.
321 // Merge the node types
322 NodeType |= N->NodeType;
323 N->NodeType = 0; // N is now a dead node.
325 // If this merging into node has more than just void nodes in it, merge!
326 assert(!N->TypeEntries.empty() && "TypeEntries is empty for a node?");
327 if (N->TypeEntries.size() != 1 || N->TypeEntries[0].Ty != Type::VoidTy) {
328 // If the current node just has a Void entry in it, remove it.
329 if (TypeEntries.size() == 1 && TypeEntries[0].Ty == Type::VoidTy)
332 // Adjust all of the type entries we are merging in by the offset... and add
333 // them to the TypeEntries list.
335 if (NOffset != 0) { // This case is common enough to optimize for
336 // Offset all of the TypeEntries in N with their new offset
337 for (unsigned i = 0, e = N->TypeEntries.size(); i != e; ++i)
338 N->TypeEntries[i].Offset += NOffset;
341 MergeSortedVectors(TypeEntries, N->TypeEntries);
343 N->TypeEntries.clear();
346 // Merge the globals list...
347 if (!N->Globals.empty()) {
348 MergeSortedVectors(Globals, N->Globals);
350 // Delete the globals from the old node...
355 //===----------------------------------------------------------------------===//
356 // DSCallSite Implementation
357 //===----------------------------------------------------------------------===//
359 // Define here to avoid including iOther.h and BasicBlock.h in DSGraph.h
360 Function &DSCallSite::getCaller() const {
361 return *Inst->getParent()->getParent();
364 template <typename CopyFunctor>
365 DSCallSite::DSCallSite(const DSCallSite &FromCall, CopyFunctor nodeCopier)
366 : Inst(FromCall.Inst) {
368 RetVal = nodeCopier(&FromCall.RetVal);
369 Callee = nodeCopier(&FromCall.Callee);
371 CallArgs.reserve(FromCall.CallArgs.size());
372 for (unsigned j = 0, ej = FromCall.CallArgs.size(); j != ej; ++j)
373 CallArgs.push_back(nodeCopier(&FromCall.CallArgs[j]));
377 //===----------------------------------------------------------------------===//
378 // DSGraph Implementation
379 //===----------------------------------------------------------------------===//
381 DSGraph::DSGraph(const DSGraph &G) : Func(G.Func) {
382 std::map<const DSNode*, DSNode*> NodeMap;
383 RetNode = cloneInto(G, ValueMap, NodeMap);
386 DSGraph::~DSGraph() {
387 FunctionCalls.clear();
392 // Drop all intra-node references, so that assertions don't fail...
393 std::for_each(Nodes.begin(), Nodes.end(),
394 std::mem_fun(&DSNode::dropAllReferences));
397 // Delete all of the nodes themselves...
398 std::for_each(Nodes.begin(), Nodes.end(), deleter<DSNode>);
401 // dump - Allow inspection of graph in a debugger.
402 void DSGraph::dump() const { print(std::cerr); }
405 static DSNodeHandle copyHelper(const DSNodeHandle* fromNode,
406 std::map<const DSNode*, DSNode*> *NodeMap) {
407 return DSNodeHandle((*NodeMap)[fromNode->getNode()], fromNode->getOffset());
410 // Helper function used to clone a function list.
412 static void CopyFunctionCallsList(const vector<DSCallSite>& fromCalls,
413 vector<DSCallSite> &toCalls,
414 std::map<const DSNode*, DSNode*> &NodeMap) {
415 unsigned FC = toCalls.size(); // FirstCall
416 toCalls.reserve(FC+fromCalls.size());
417 for (unsigned i = 0, ei = fromCalls.size(); i != ei; ++i)
418 toCalls.push_back(DSCallSite(fromCalls[i],
419 std::bind2nd(std::ptr_fun(©Helper), &NodeMap)));
422 /// remapLinks - Change all of the Links in the current node according to the
423 /// specified mapping.
424 void DSNode::remapLinks(std::map<const DSNode*, DSNode*> &OldNodeMap) {
425 for (unsigned i = 0, e = Links.size(); i != e; ++i)
426 Links[i].setNode(OldNodeMap[Links[i].getNode()]);
430 // cloneInto - Clone the specified DSGraph into the current graph, returning the
431 // Return node of the graph. The translated ValueMap for the old function is
432 // filled into the OldValMap member. If StripLocals is set to true, Scalar and
433 // Alloca markers are removed from the graph, as the graph is being cloned into
434 // a calling function's graph.
436 DSNodeHandle DSGraph::cloneInto(const DSGraph &G,
437 std::map<Value*, DSNodeHandle> &OldValMap,
438 std::map<const DSNode*, DSNode*> &OldNodeMap,
439 bool StripScalars, bool StripAllocas,
440 bool CopyCallers, bool CopyOrigCalls) {
441 assert(OldNodeMap.empty() && "Returned OldNodeMap should be empty!");
443 unsigned FN = Nodes.size(); // First new node...
445 // Duplicate all of the nodes, populating the node map...
446 Nodes.reserve(FN+G.Nodes.size());
447 for (unsigned i = 0, e = G.Nodes.size(); i != e; ++i) {
448 DSNode *Old = G.Nodes[i];
449 DSNode *New = new DSNode(*Old);
450 Nodes.push_back(New);
451 OldNodeMap[Old] = New;
454 // Rewrite the links in the new nodes to point into the current graph now.
455 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
456 Nodes[i]->remapLinks(OldNodeMap);
458 // Remove local markers as specified
459 unsigned char StripBits = (StripScalars ? DSNode::ScalarNode : 0) |
460 (StripAllocas ? DSNode::AllocaNode : 0);
462 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
463 Nodes[i]->NodeType &= ~StripBits;
465 // Copy the value map... and merge all of the global nodes...
466 for (std::map<Value*, DSNodeHandle>::const_iterator I = G.ValueMap.begin(),
467 E = G.ValueMap.end(); I != E; ++I) {
468 DSNodeHandle &H = OldValMap[I->first];
469 H = DSNodeHandle(OldNodeMap[I->second.getNode()], I->second.getOffset());
471 if (isa<GlobalValue>(I->first)) { // Is this a global?
472 std::map<Value*, DSNodeHandle>::iterator GVI = ValueMap.find(I->first);
473 if (GVI != ValueMap.end()) { // Is the global value in this fun already?
474 GVI->second.mergeWith(H);
476 ValueMap[I->first] = H; // Add global pointer to this graph
480 // Copy the function calls list...
481 CopyFunctionCallsList(G.FunctionCalls, FunctionCalls, OldNodeMap);
484 // Return the returned node pointer...
485 return DSNodeHandle(OldNodeMap[G.RetNode.getNode()], G.RetNode.getOffset());
489 // cloneGlobalInto - Clone the given global node and all its target links
490 // (and all their llinks, recursively).
492 DSNode *DSGraph::cloneGlobalInto(const DSNode *GNode) {
493 if (GNode == 0 || GNode->getGlobals().size() == 0) return 0;
495 // If a clone has already been created for GNode, return it.
496 DSNodeHandle& ValMapEntry = ValueMap[GNode->getGlobals()[0]];
497 if (ValMapEntry != 0)
500 // Clone the node and update the ValMap.
501 DSNode* NewNode = new DSNode(*GNode);
502 ValMapEntry = NewNode; // j=0 case of loop below!
503 Nodes.push_back(NewNode);
504 for (unsigned j = 1, N = NewNode->getGlobals().size(); j < N; ++j)
505 ValueMap[NewNode->getGlobals()[j]] = NewNode;
507 // Rewrite the links in the new node to point into the current graph.
508 for (unsigned j = 0, e = GNode->getNumLinks(); j != e; ++j)
509 NewNode->setLink(j, cloneGlobalInto(GNode->getLink(j)));
516 // markIncompleteNodes - Mark the specified node as having contents that are not
517 // known with the current analysis we have performed. Because a node makes all
518 // of the nodes it can reach imcomplete if the node itself is incomplete, we
519 // must recursively traverse the data structure graph, marking all reachable
520 // nodes as incomplete.
522 static void markIncompleteNode(DSNode *N) {
523 // Stop recursion if no node, or if node already marked...
524 if (N == 0 || (N->NodeType & DSNode::Incomplete)) return;
526 // Actually mark the node
527 N->NodeType |= DSNode::Incomplete;
529 // Recusively process children...
530 for (unsigned i = 0, e = N->getSize(); i != e; ++i)
531 if (DSNodeHandle *DSNH = N->getLink(i))
532 markIncompleteNode(DSNH->getNode());
536 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
537 // modified by other functions that have not been resolved yet. This marks
538 // nodes that are reachable through three sources of "unknownness":
540 // Global Variables, Function Calls, and Incoming Arguments
542 // For any node that may have unknown components (because something outside the
543 // scope of current analysis may have modified it), the 'Incomplete' flag is
544 // added to the NodeType.
546 void DSGraph::markIncompleteNodes(bool markFormalArgs) {
547 // Mark any incoming arguments as incomplete...
548 if (markFormalArgs && Func)
549 for (Function::aiterator I = Func->abegin(), E = Func->aend(); I != E; ++I)
550 if (isPointerType(I->getType()) && ValueMap.find(I) != ValueMap.end()) {
551 DSNodeHandle &INH = ValueMap[I];
552 if (INH.getNode() && INH.hasLink(0))
553 markIncompleteNode(ValueMap[I].getLink(0)->getNode());
556 // Mark stuff passed into functions calls as being incomplete...
557 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
558 DSCallSite &Call = FunctionCalls[i];
559 // Then the return value is certainly incomplete!
560 markIncompleteNode(Call.getRetVal().getNode());
562 // The call does not make the function argument incomplete...
564 // All arguments to the function call are incomplete though!
565 for (unsigned i = 0, e = Call.getNumPtrArgs(); i != e; ++i)
566 markIncompleteNode(Call.getPtrArg(i).getNode());
569 // Mark all of the nodes pointed to by global or cast nodes as incomplete...
570 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
571 if (Nodes[i]->NodeType & DSNode::GlobalNode) {
572 DSNode *N = Nodes[i];
573 for (unsigned i = 0, e = N->getSize(); i != e; ++i)
574 if (DSNodeHandle *DSNH = N->getLink(i))
575 markIncompleteNode(DSNH->getNode());
579 // removeRefsToGlobal - Helper function that removes globals from the
580 // ValueMap so that the referrer count will go down to zero.
581 static void removeRefsToGlobal(DSNode* N,
582 std::map<Value*, DSNodeHandle> &ValueMap) {
583 while (!N->getGlobals().empty()) {
584 GlobalValue *GV = N->getGlobals().back();
585 N->getGlobals().pop_back();
591 // isNodeDead - This method checks to see if a node is dead, and if it isn't, it
592 // checks to see if there are simple transformations that it can do to make it
595 bool DSGraph::isNodeDead(DSNode *N) {
596 // Is it a trivially dead shadow node...
597 if (N->getReferrers().empty() && N->NodeType == 0)
600 // Is it a function node or some other trivially unused global?
601 if (N->NodeType != 0 &&
602 (N->NodeType & ~DSNode::GlobalNode) == 0 &&
604 N->getReferrers().size() == N->getGlobals().size()) {
606 // Remove the globals from the ValueMap, so that the referrer count will go
608 removeRefsToGlobal(N, ValueMap);
609 assert(N->getReferrers().empty() && "Referrers should all be gone now!");
616 static void removeIdenticalCalls(vector<DSCallSite> &Calls,
617 const std::string &where) {
618 // Remove trivially identical function calls
619 unsigned NumFns = Calls.size();
620 std::sort(Calls.begin(), Calls.end());
621 Calls.erase(std::unique(Calls.begin(), Calls.end()),
624 DEBUG(if (NumFns != Calls.size())
625 std::cerr << "Merged " << (NumFns-Calls.size())
626 << " call nodes in " << where << "\n";);
629 // removeTriviallyDeadNodes - After the graph has been constructed, this method
630 // removes all unreachable nodes that are created because they got merged with
631 // other nodes in the graph. These nodes will all be trivially unreachable, so
632 // we don't have to perform any non-trivial analysis here.
634 void DSGraph::removeTriviallyDeadNodes(bool KeepAllGlobals) {
635 for (unsigned i = 0; i != Nodes.size(); ++i)
636 if (!KeepAllGlobals || !(Nodes[i]->NodeType & DSNode::GlobalNode))
637 if (isNodeDead(Nodes[i])) { // This node is dead!
638 delete Nodes[i]; // Free memory...
639 Nodes.erase(Nodes.begin()+i--); // Remove from node list...
642 removeIdenticalCalls(FunctionCalls, Func ? Func->getName() : "");
646 // markAlive - Simple graph walker that recursively traverses the graph, marking
647 // stuff to be alive.
649 static void markAlive(DSNode *N, std::set<DSNode*> &Alive) {
653 for (unsigned i = 0, e = N->getSize(); i != e; ++i)
654 if (DSNodeHandle *DSNH = N->getLink(i))
655 if (!Alive.count(DSNH->getNode()))
656 markAlive(DSNH->getNode(), Alive);
659 static bool checkGlobalAlive(DSNode *N, std::set<DSNode*> &Alive,
660 std::set<DSNode*> &Visiting) {
661 if (N == 0) return false;
663 if (Visiting.count(N)) return false; // terminate recursion on a cycle
666 // If any immediate successor is alive, N is alive
667 for (unsigned i = 0, e = N->getSize(); i != e; ++i)
668 if (DSNodeHandle *DSNH = N->getLink(i))
669 if (Alive.count(DSNH->getNode())) {
674 // Else if any successor reaches a live node, N is alive
675 for (unsigned i = 0, e = N->getSize(); i != e; ++i)
676 if (DSNodeHandle *DSNH = N->getLink(i))
677 if (checkGlobalAlive(DSNH->getNode(), Alive, Visiting)) {
678 Visiting.erase(N); return true;
686 // markGlobalsIteration - Recursive helper function for markGlobalsAlive().
687 // This would be unnecessary if function calls were real nodes! In that case,
688 // the simple iterative loop in the first few lines below suffice.
690 static void markGlobalsIteration(std::set<DSNode*>& GlobalNodes,
691 vector<DSCallSite> &Calls,
692 std::set<DSNode*> &Alive,
695 // Iterate, marking globals or cast nodes alive until no new live nodes
696 // are added to Alive
697 std::set<DSNode*> Visiting; // Used to identify cycles
698 std::set<DSNode*>::iterator I = GlobalNodes.begin(), E = GlobalNodes.end();
699 for (size_t liveCount = 0; liveCount < Alive.size(); ) {
700 liveCount = Alive.size();
702 if (Alive.count(*I) == 0) {
704 if (checkGlobalAlive(*I, Alive, Visiting))
705 markAlive(*I, Alive);
709 // Find function calls with some dead and some live nodes.
710 // Since all call nodes must be live if any one is live, we have to mark
711 // all nodes of the call as live and continue the iteration (via recursion).
713 bool Recurse = false;
714 for (unsigned i = 0, ei = Calls.size(); i < ei; ++i) {
715 bool CallIsDead = true, CallHasDeadArg = false;
716 DSCallSite &CS = Calls[i];
717 for (unsigned j = 0, ej = CS.getNumPtrArgs(); j != ej; ++j)
718 if (DSNode *N = CS.getPtrArg(j).getNode()) {
719 bool ArgIsDead = !Alive.count(N);
720 CallHasDeadArg |= ArgIsDead;
721 CallIsDead &= ArgIsDead;
724 if (DSNode *N = CS.getRetVal().getNode()) {
725 bool RetIsDead = !Alive.count(N);
726 CallHasDeadArg |= RetIsDead;
727 CallIsDead &= RetIsDead;
730 DSNode *N = CS.getCallee().getNode();
731 bool FnIsDead = !Alive.count(N);
732 CallHasDeadArg |= FnIsDead;
733 CallIsDead &= FnIsDead;
735 if (!CallIsDead && CallHasDeadArg) {
736 // Some node in this call is live and another is dead.
737 // Mark all nodes of call as live and iterate once more.
739 for (unsigned j = 0, ej = CS.getNumPtrArgs(); j != ej; ++j)
740 markAlive(CS.getPtrArg(j).getNode(), Alive);
741 markAlive(CS.getRetVal().getNode(), Alive);
742 markAlive(CS.getCallee().getNode(), Alive);
746 markGlobalsIteration(GlobalNodes, Calls, Alive, FilterCalls);
751 // markGlobalsAlive - Mark global nodes and cast nodes alive if they
752 // can reach any other live node. Since this can produce new live nodes,
753 // we use a simple iterative algorithm.
755 static void markGlobalsAlive(DSGraph &G, std::set<DSNode*> &Alive,
757 // Add global and cast nodes to a set so we don't walk all nodes every time
758 std::set<DSNode*> GlobalNodes;
759 for (unsigned i = 0, e = G.getNodes().size(); i != e; ++i)
760 if (G.getNodes()[i]->NodeType & DSNode::GlobalNode)
761 GlobalNodes.insert(G.getNodes()[i]);
763 // Add all call nodes to the same set
764 vector<DSCallSite> &Calls = G.getFunctionCalls();
766 for (unsigned i = 0, e = Calls.size(); i != e; ++i) {
767 for (unsigned j = 0, e = Calls[i].getNumPtrArgs(); j != e; ++j)
768 if (DSNode *N = Calls[i].getPtrArg(j).getNode())
769 GlobalNodes.insert(N);
770 if (DSNode *N = Calls[i].getRetVal().getNode())
771 GlobalNodes.insert(N);
772 if (DSNode *N = Calls[i].getCallee().getNode())
773 GlobalNodes.insert(N);
777 // Iterate and recurse until no new live node are discovered.
778 // This would be a simple iterative loop if function calls were real nodes!
779 markGlobalsIteration(GlobalNodes, Calls, Alive, FilterCalls);
781 // Free up references to dead globals from the ValueMap
782 std::set<DSNode*>::iterator I=GlobalNodes.begin(), E=GlobalNodes.end();
784 if (Alive.count(*I) == 0)
785 removeRefsToGlobal(*I, G.getValueMap());
787 // Delete dead function calls
789 for (int ei = Calls.size(), i = ei-1; i >= 0; --i) {
790 bool CallIsDead = true;
791 for (unsigned j = 0, ej = Calls[i].getNumPtrArgs();
792 CallIsDead && j != ej; ++j)
793 CallIsDead = Alive.count(Calls[i].getPtrArg(j).getNode()) == 0;
795 Calls.erase(Calls.begin() + i); // remove the call entirely
799 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
800 // subgraphs that are unreachable. This often occurs because the data
801 // structure doesn't "escape" into it's caller, and thus should be eliminated
802 // from the caller's graph entirely. This is only appropriate to use when
805 void DSGraph::removeDeadNodes(bool KeepAllGlobals, bool KeepCalls) {
806 assert((!KeepAllGlobals || KeepCalls) &&
807 "KeepAllGlobals without KeepCalls is meaningless");
809 // Reduce the amount of work we have to do...
810 removeTriviallyDeadNodes(KeepAllGlobals);
812 // FIXME: Merge nontrivially identical call nodes...
814 // Alive - a set that holds all nodes found to be reachable/alive.
815 std::set<DSNode*> Alive;
817 // If KeepCalls, mark all nodes reachable by call nodes as alive...
819 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
820 for (unsigned j = 0, e = FunctionCalls[i].getNumPtrArgs(); j != e; ++j)
821 markAlive(FunctionCalls[i].getPtrArg(j).getNode(), Alive);
822 markAlive(FunctionCalls[i].getRetVal().getNode(), Alive);
823 markAlive(FunctionCalls[i].getCallee().getNode(), Alive);
827 for (unsigned i = 0, e = OrigFunctionCalls.size(); i != e; ++i)
828 for (unsigned j = 0, e = OrigFunctionCalls[i].size(); j != e; ++j)
829 markAlive(OrigFunctionCalls[i][j].getNode(), Alive);
832 // Mark all nodes reachable by scalar nodes (and global nodes, if
833 // keeping them was specified) as alive...
834 unsigned char keepBits = DSNode::ScalarNode |
835 (KeepAllGlobals ? DSNode::GlobalNode : 0);
836 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
837 if (Nodes[i]->NodeType & keepBits)
838 markAlive(Nodes[i], Alive);
840 // The return value is alive as well...
841 markAlive(RetNode.getNode(), Alive);
843 // Mark all globals or cast nodes that can reach a live node as alive.
844 // This also marks all nodes reachable from such nodes as alive.
845 // Of course, if KeepAllGlobals is specified, they would be live already.
847 markGlobalsAlive(*this, Alive, ! KeepCalls);
849 // Loop over all unreachable nodes, dropping their references...
850 vector<DSNode*> DeadNodes;
851 DeadNodes.reserve(Nodes.size()); // Only one allocation is allowed.
852 for (unsigned i = 0; i != Nodes.size(); ++i)
853 if (!Alive.count(Nodes[i])) {
854 DSNode *N = Nodes[i];
855 Nodes.erase(Nodes.begin()+i--); // Erase node from alive list.
856 DeadNodes.push_back(N); // Add node to our list of dead nodes
857 N->dropAllReferences(); // Drop all outgoing edges
860 // Delete all dead nodes...
861 std::for_each(DeadNodes.begin(), DeadNodes.end(), deleter<DSNode>);
866 // maskNodeTypes - Apply a mask to all of the node types in the graph. This
867 // is useful for clearing out markers like Scalar or Incomplete.
869 void DSGraph::maskNodeTypes(unsigned char Mask) {
870 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
871 Nodes[i]->NodeType &= Mask;
876 //===----------------------------------------------------------------------===//
877 // GlobalDSGraph Implementation
878 //===----------------------------------------------------------------------===//
880 GlobalDSGraph::GlobalDSGraph() : DSGraph(*(Function*)0, this) {
883 GlobalDSGraph::~GlobalDSGraph() {
884 assert(Referrers.size() == 0 &&
885 "Deleting global graph while references from other graphs exist");
888 void GlobalDSGraph::addReference(const DSGraph* referrer) {
889 if (referrer != this)
890 Referrers.insert(referrer);
893 void GlobalDSGraph::removeReference(const DSGraph* referrer) {
894 if (referrer != this) {
895 assert(Referrers.find(referrer) != Referrers.end() && "This is very bad!");
896 Referrers.erase(referrer);
897 if (Referrers.size() == 0)
902 // Bits used in the next function
903 static const char ExternalTypeBits = DSNode::GlobalNode | DSNode::NewNode;
906 // GlobalDSGraph::cloneNodeInto - Clone a global node and all its externally
907 // visible target links (and recursively their such links) into this graph.
908 // NodeCache maps the node being cloned to its clone in the Globals graph,
909 // in order to track cycles.
910 // GlobalsAreFinal is a flag that says whether it is safe to assume that
911 // an existing global node is complete. This is important to avoid
912 // reinserting all globals when inserting Calls to functions.
913 // This is a helper function for cloneGlobals and cloneCalls.
915 DSNode* GlobalDSGraph::cloneNodeInto(DSNode *OldNode,
916 std::map<const DSNode*, DSNode*> &NodeCache,
917 bool GlobalsAreFinal) {
918 if (OldNode == 0) return 0;
920 // The caller should check this is an external node. Just more efficient...
921 assert((OldNode->NodeType & ExternalTypeBits) && "Non-external node");
923 // If a clone has already been created for OldNode, return it.
924 DSNode*& CacheEntry = NodeCache[OldNode];
928 // The result value...
931 // If nodes already exist for any of the globals of OldNode,
932 // merge all such nodes together since they are merged in OldNode.
933 // If ValueCacheIsFinal==true, look for an existing node that has
934 // an identical list of globals and return it if it exists.
936 for (unsigned j = 0, N = OldNode->getGlobals().size(); j != N; ++j)
937 if (DSNode *PrevNode = ValueMap[OldNode->getGlobals()[j]].getNode()) {
939 NewNode = PrevNode; // first existing node found
940 if (GlobalsAreFinal && j == 0)
941 if (OldNode->getGlobals() == PrevNode->getGlobals()) {
942 CacheEntry = NewNode;
946 else if (NewNode != PrevNode) { // found another, different from prev
947 // update ValMap *before* merging PrevNode into NewNode
948 for (unsigned k = 0, NK = PrevNode->getGlobals().size(); k < NK; ++k)
949 ValueMap[PrevNode->getGlobals()[k]] = NewNode;
950 NewNode->mergeWith(PrevNode);
952 } else if (NewNode != 0) {
953 ValueMap[OldNode->getGlobals()[j]] = NewNode; // add the merged node
956 // If no existing node was found, clone the node and update the ValMap.
958 NewNode = new DSNode(*OldNode);
959 Nodes.push_back(NewNode);
960 for (unsigned j = 0, e = NewNode->getNumLinks(); j != e; ++j)
961 NewNode->setLink(j, 0);
962 for (unsigned j = 0, N = NewNode->getGlobals().size(); j < N; ++j)
963 ValueMap[NewNode->getGlobals()[j]] = NewNode;
966 NewNode->NodeType |= OldNode->NodeType; // Markers may be different!
968 // Add the entry to NodeCache
969 CacheEntry = NewNode;
971 // Rewrite the links in the new node to point into the current graph,
972 // but only for links to external nodes. Set other links to NULL.
973 for (unsigned j = 0, e = OldNode->getNumLinks(); j != e; ++j) {
974 DSNode* OldTarget = OldNode->getLink(j);
975 if (OldTarget && (OldTarget->NodeType & ExternalTypeBits)) {
976 DSNode* NewLink = this->cloneNodeInto(OldTarget, NodeCache);
977 if (NewNode->getLink(j))
978 NewNode->getLink(j)->mergeWith(NewLink);
980 NewNode->setLink(j, NewLink);
984 // Remove all local markers
985 NewNode->NodeType &= ~(DSNode::AllocaNode | DSNode::ScalarNode);
991 // GlobalDSGraph::cloneGlobals - Clone global nodes and all their externally
992 // visible target links (and recursively their such links) into this graph.
994 void GlobalDSGraph::cloneGlobals(DSGraph& Graph, bool CloneCalls) {
995 std::map<const DSNode*, DSNode*> NodeCache;
997 for (unsigned i = 0, N = Graph.Nodes.size(); i < N; ++i)
998 if (Graph.Nodes[i]->NodeType & DSNode::GlobalNode)
999 GlobalsGraph->cloneNodeInto(Graph.Nodes[i], NodeCache, false);
1001 GlobalsGraph->cloneCalls(Graph);
1003 GlobalsGraph->removeDeadNodes(/*KeepAllGlobals*/ true, /*KeepCalls*/ true);
1008 // GlobalDSGraph::cloneCalls - Clone function calls and their visible target
1009 // links (and recursively their such links) into this graph.
1011 void GlobalDSGraph::cloneCalls(DSGraph& Graph) {
1012 std::map<const DSNode*, DSNode*> NodeCache;
1013 vector<DSCallSite >& FromCalls =Graph.FunctionCalls;
1015 FunctionCalls.reserve(FunctionCalls.size() + FromCalls.size());
1017 for (int i = 0, ei = FromCalls.size(); i < ei; ++i) {
1018 DSCallSite& callCopy = FunctionCalls.back();
1019 callCopy.reserve(FromCalls[i].size());
1020 for (unsigned j = 0, ej = FromCalls[i].size(); j != ej; ++j)
1022 ((FromCalls[i][j] && (FromCalls[i][j]->NodeType & ExternalTypeBits))
1023 ? cloneNodeInto(FromCalls[i][j], NodeCache, true)
1027 // remove trivially identical function calls
1028 removeIdenticalCalls(FunctionCalls, "Globals Graph");