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 Statistic<> NumFolds ("dsnode", "Number of nodes completely folded");
21 Statistic<> NumCallNodesMerged("dsnode", "Number of call nodes merged");
24 namespace DS { // TODO: FIXME
29 //===----------------------------------------------------------------------===//
30 // DSNode Implementation
31 //===----------------------------------------------------------------------===//
33 DSNode::DSNode(enum NodeTy NT, const Type *T)
34 : Ty(Type::VoidTy), Size(0), NodeType(NT) {
35 // Add the type entry if it is specified...
36 if (T) mergeTypeInfo(T, 0);
39 // DSNode copy constructor... do not copy over the referrers list!
40 DSNode::DSNode(const DSNode &N)
41 : Links(N.Links), Globals(N.Globals), Ty(N.Ty), Size(N.Size),
42 NodeType(N.NodeType) {
45 void DSNode::removeReferrer(DSNodeHandle *H) {
46 // Search backwards, because we depopulate the list from the back for
47 // efficiency (because it's a vector).
48 vector<DSNodeHandle*>::reverse_iterator I =
49 std::find(Referrers.rbegin(), Referrers.rend(), H);
50 assert(I != Referrers.rend() && "Referrer not pointing to node!");
51 Referrers.erase(I.base()-1);
54 // addGlobal - Add an entry for a global value to the Globals list. This also
55 // marks the node with the 'G' flag if it does not already have it.
57 void DSNode::addGlobal(GlobalValue *GV) {
58 // Keep the list sorted.
59 vector<GlobalValue*>::iterator I =
60 std::lower_bound(Globals.begin(), Globals.end(), GV);
62 if (I == Globals.end() || *I != GV) {
63 //assert(GV->getType()->getElementType() == Ty);
64 Globals.insert(I, GV);
65 NodeType |= GlobalNode;
69 /// foldNodeCompletely - If we determine that this node has some funny
70 /// behavior happening to it that we cannot represent, we fold it down to a
71 /// single, completely pessimistic, node. This node is represented as a
72 /// single byte with a single TypeEntry of "void".
74 void DSNode::foldNodeCompletely() {
75 if (isNodeCompletelyFolded()) return;
79 // We are no longer typed at all...
80 Ty = DSTypeRec(Type::VoidTy, true);
83 // Loop over all of our referrers, making them point to our zero bytes of
85 for (vector<DSNodeHandle*>::iterator I = Referrers.begin(), E=Referrers.end();
89 // If we have links, merge all of our outgoing links together...
90 for (unsigned i = 1, e = Links.size(); i < e; ++i)
91 Links[0].mergeWith(Links[i]);
95 /// isNodeCompletelyFolded - Return true if this node has been completely
96 /// folded down to something that can never be expanded, effectively losing
97 /// all of the field sensitivity that may be present in the node.
99 bool DSNode::isNodeCompletelyFolded() const {
100 return getSize() == 1 && Ty.Ty == Type::VoidTy && Ty.isArray;
104 /// mergeTypeInfo - This method merges the specified type into the current node
105 /// at the specified offset. This may update the current node's type record if
106 /// this gives more information to the node, it may do nothing to the node if
107 /// this information is already known, or it may merge the node completely (and
108 /// return true) if the information is incompatible with what is already known.
110 /// This method returns true if the node is completely folded, otherwise false.
112 bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset) {
113 // Check to make sure the Size member is up-to-date. Size can be one of the
115 // Size = 0, Ty = Void: Nothing is known about this node.
116 // Size = 0, Ty = FnTy: FunctionPtr doesn't have a size, so we use zero
117 // Size = 1, Ty = Void, Array = 1: The node is collapsed
118 // Otherwise, sizeof(Ty) = Size
120 assert(((Size == 0 && Ty.Ty == Type::VoidTy && !Ty.isArray) ||
121 (Size == 0 && !Ty.Ty->isSized() && !Ty.isArray) ||
122 (Size == 1 && Ty.Ty == Type::VoidTy && Ty.isArray) ||
123 (Size == 0 && !Ty.Ty->isSized() && !Ty.isArray) ||
124 (TD.getTypeSize(Ty.Ty) == Size)) &&
125 "Size member of DSNode doesn't match the type structure!");
126 assert(NewTy != Type::VoidTy && "Cannot merge void type into DSNode!");
128 if (Offset == 0 && NewTy == Ty.Ty)
129 return false; // This should be a common case, handle it efficiently
131 // Return true immediately if the node is completely folded.
132 if (isNodeCompletelyFolded()) return true;
134 // If this is an array type, eliminate the outside arrays because they won't
135 // be used anyway. This greatly reduces the size of large static arrays used
136 // as global variables, for example.
138 bool WillBeArray = false;
139 while (const ArrayType *AT = dyn_cast<ArrayType>(NewTy)) {
140 // FIXME: we might want to keep small arrays, but must be careful about
141 // things like: [2 x [10000 x int*]]
142 NewTy = AT->getElementType();
146 // Figure out how big the new type we're merging in is...
147 unsigned NewTySize = NewTy->isSized() ? TD.getTypeSize(NewTy) : 0;
149 // Otherwise check to see if we can fold this type into the current node. If
150 // we can't, we fold the node completely, if we can, we potentially update our
153 if (Ty.Ty == Type::VoidTy) {
154 // If this is the first type that this node has seen, just accept it without
156 assert(Offset == 0 && "Cannot have an offset into a void node!");
157 assert(!Ty.isArray && "This shouldn't happen!");
159 Ty.isArray = WillBeArray;
162 // Calculate the number of outgoing links from this node.
163 Links.resize((Size+DS::PointerSize-1) >> DS::PointerShift);
167 // Handle node expansion case here...
168 if (Offset+NewTySize > Size) {
169 // It is illegal to grow this node if we have treated it as an array of
172 foldNodeCompletely();
176 if (Offset) { // We could handle this case, but we don't for now...
177 DEBUG(std::cerr << "UNIMP: Trying to merge a growth type into "
178 << "offset != 0: Collapsing!\n");
179 foldNodeCompletely();
183 // Okay, the situation is nice and simple, we are trying to merge a type in
184 // at offset 0 that is bigger than our current type. Implement this by
185 // switching to the new type and then merge in the smaller one, which should
186 // hit the other code path here. If the other code path decides it's not
187 // ok, it will collapse the node as appropriate.
189 const Type *OldTy = Ty.Ty;
191 Ty.isArray = WillBeArray;
194 // Must grow links to be the appropriate size...
195 Links.resize((Size+DS::PointerSize-1) >> DS::PointerShift);
197 // Merge in the old type now... which is guaranteed to be smaller than the
199 return mergeTypeInfo(OldTy, 0);
202 assert(Offset <= Size &&
203 "Cannot merge something into a part of our type that doesn't exist!");
205 // Find the section of Ty.Ty that NewTy overlaps with... first we find the
206 // type that starts at offset Offset.
209 const Type *SubType = Ty.Ty;
211 assert(Offset-O < TD.getTypeSize(SubType) && "Offset out of range!");
213 switch (SubType->getPrimitiveID()) {
214 case Type::StructTyID: {
215 const StructType *STy = cast<StructType>(SubType);
216 const StructLayout &SL = *TD.getStructLayout(STy);
218 unsigned i = 0, e = SL.MemberOffsets.size();
219 for (; i+1 < e && SL.MemberOffsets[i+1] <= Offset-O; ++i)
222 // The offset we are looking for must be in the i'th element...
223 SubType = STy->getElementTypes()[i];
224 O += SL.MemberOffsets[i];
227 case Type::ArrayTyID: {
228 SubType = cast<ArrayType>(SubType)->getElementType();
229 unsigned ElSize = TD.getTypeSize(SubType);
230 unsigned Remainder = (Offset-O) % ElSize;
231 O = Offset-Remainder;
235 assert(0 && "Unknown type!");
239 assert(O == Offset && "Could not achieve the correct offset!");
241 // If we found our type exactly, early exit
242 if (SubType == NewTy) return false;
244 // Okay, so we found the leader type at the offset requested. Search the list
245 // of types that starts at this offset. If SubType is currently an array or
246 // structure, the type desired may actually be the first element of the
249 unsigned SubTypeSize = SubType->isSized() ? TD.getTypeSize(SubType) : 0;
250 while (SubType != NewTy) {
251 const Type *NextSubType = 0;
252 unsigned NextSubTypeSize = 0;
253 switch (SubType->getPrimitiveID()) {
254 case Type::StructTyID:
255 NextSubType = cast<StructType>(SubType)->getElementTypes()[0];
256 NextSubTypeSize = TD.getTypeSize(SubType);
258 case Type::ArrayTyID:
259 NextSubType = cast<ArrayType>(SubType)->getElementType();
260 NextSubTypeSize = TD.getTypeSize(SubType);
266 if (NextSubType == 0)
267 break; // In the default case, break out of the loop
269 if (NextSubTypeSize < NewTySize)
270 break; // Don't allow shrinking to a smaller type than NewTySize
271 SubType = NextSubType;
272 SubTypeSize = NextSubTypeSize;
275 // If we found the type exactly, return it...
276 if (SubType == NewTy)
279 // Check to see if we have a compatible, but different type...
280 if (NewTySize == SubTypeSize) {
281 // Check to see if this type is obviously convertable... int -> uint f.e.
282 if (NewTy->isLosslesslyConvertableTo(SubType))
285 // Check to see if we have a pointer & integer mismatch going on here,
286 // loading a pointer as a long, for example.
288 if (SubType->isInteger() && isa<PointerType>(NewTy) ||
289 NewTy->isInteger() && isa<PointerType>(SubType))
295 DEBUG(std::cerr << "MergeTypeInfo Folding OrigTy: " << Ty.Ty
296 << "\n due to:" << NewTy << " @ " << Offset << "!\n"
297 << "SubType: " << SubType << "\n\n");
299 foldNodeCompletely();
305 // addEdgeTo - Add an edge from the current node to the specified node. This
306 // can cause merging of nodes in the graph.
308 void DSNode::addEdgeTo(unsigned Offset, const DSNodeHandle &NH) {
309 if (NH.getNode() == 0) return; // Nothing to do
311 DSNodeHandle &ExistingEdge = getLink(Offset);
312 if (ExistingEdge.getNode()) {
313 // Merge the two nodes...
314 ExistingEdge.mergeWith(NH);
315 } else { // No merging to perform...
316 setLink(Offset, NH); // Just force a link in there...
321 // MergeSortedVectors - Efficiently merge a vector into another vector where
322 // duplicates are not allowed and both are sorted. This assumes that 'T's are
323 // efficiently copyable and have sane comparison semantics.
326 void MergeSortedVectors(vector<T> &Dest, const vector<T> &Src) {
327 // By far, the most common cases will be the simple ones. In these cases,
328 // avoid having to allocate a temporary vector...
330 if (Src.empty()) { // Nothing to merge in...
332 } else if (Dest.empty()) { // Just copy the result in...
334 } else if (Src.size() == 1) { // Insert a single element...
336 typename vector<T>::iterator I =
337 std::lower_bound(Dest.begin(), Dest.end(), V);
338 if (I == Dest.end() || *I != Src[0]) // If not already contained...
339 Dest.insert(I, Src[0]);
340 } else if (Dest.size() == 1) {
341 T Tmp = Dest[0]; // Save value in temporary...
342 Dest = Src; // Copy over list...
343 typename vector<T>::iterator I =
344 std::lower_bound(Dest.begin(), Dest.end(),Tmp);
345 if (I == Dest.end() || *I != Src[0]) // If not already contained...
346 Dest.insert(I, Src[0]);
349 // Make a copy to the side of Dest...
352 // Make space for all of the type entries now...
353 Dest.resize(Dest.size()+Src.size());
355 // Merge the two sorted ranges together... into Dest.
356 std::merge(Old.begin(), Old.end(), Src.begin(), Src.end(), Dest.begin());
358 // Now erase any duplicate entries that may have accumulated into the
359 // vectors (because they were in both of the input sets)
360 Dest.erase(std::unique(Dest.begin(), Dest.end()), Dest.end());
365 // mergeWith - Merge this node and the specified node, moving all links to and
366 // from the argument node into the current node, deleting the node argument.
367 // Offset indicates what offset the specified node is to be merged into the
370 // The specified node may be a null pointer (in which case, nothing happens).
372 void DSNode::mergeWith(const DSNodeHandle &NH, unsigned Offset) {
373 DSNode *N = NH.getNode();
374 if (N == 0 || (N == this && NH.getOffset() == Offset))
377 assert((N->NodeType & DSNode::DEAD) == 0);
378 assert((NodeType & DSNode::DEAD) == 0);
379 assert(!hasNoReferrers() && "Should not try to fold a useless node!");
382 // We cannot merge two pieces of the same node together, collapse the node
384 DEBUG(std::cerr << "Attempting to merge two chunks of"
385 << " the same node together!\n");
386 foldNodeCompletely();
390 // Merge the type entries of the two nodes together...
391 if (N->Ty.Ty != Type::VoidTy) {
392 mergeTypeInfo(N->Ty.Ty, Offset);
394 // mergeTypeInfo can cause collapsing, which can cause this node to become
396 if (hasNoReferrers()) return;
398 assert((NodeType & DSNode::DEAD) == 0);
400 // If we are merging a node with a completely folded node, then both nodes are
401 // now completely folded.
403 if (isNodeCompletelyFolded()) {
404 if (!N->isNodeCompletelyFolded()) {
405 N->foldNodeCompletely();
406 if (hasNoReferrers()) return;
408 } else if (N->isNodeCompletelyFolded()) {
409 foldNodeCompletely();
411 if (hasNoReferrers()) return;
414 assert((NodeType & DSNode::DEAD) == 0);
416 if (this == N || N == 0) return;
417 assert((NodeType & DSNode::DEAD) == 0);
419 // If both nodes are not at offset 0, make sure that we are merging the node
420 // at an later offset into the node with the zero offset.
422 if (Offset > NH.getOffset()) {
423 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
425 } else if (Offset == NH.getOffset() && getSize() < N->getSize()) {
426 // If the offsets are the same, merge the smaller node into the bigger node
427 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
432 std::cerr << "\n\nMerging:\n";
433 N->print(std::cerr, 0);
434 std::cerr << " and:\n";
438 // Now we know that Offset <= NH.Offset, so convert it so our "Offset" (with
439 // respect to NH.Offset) is now zero.
441 unsigned NOffset = NH.getOffset()-Offset;
442 unsigned NSize = N->getSize();
444 assert((NodeType & DSNode::DEAD) == 0);
446 // Remove all edges pointing at N, causing them to point to 'this' instead.
447 // Make sure to adjust their offset, not just the node pointer.
449 while (!N->Referrers.empty()) {
450 DSNodeHandle &Ref = *N->Referrers.back();
451 Ref = DSNodeHandle(this, NOffset+Ref.getOffset());
453 assert((NodeType & DSNode::DEAD) == 0);
455 // Make all of the outgoing links of N now be outgoing links of this. This
456 // can cause recursive merging!
458 for (unsigned i = 0; i < NSize; i += DS::PointerSize) {
459 DSNodeHandle &Link = N->getLink(i);
460 if (Link.getNode()) {
461 addEdgeTo((i+NOffset) % getSize(), Link);
463 // It's possible that after adding the new edge that some recursive
464 // merging just occured, causing THIS node to get merged into oblivion.
465 // If that happens, we must not try to merge any more edges into it!
467 if (Size == 0) return;
471 // Now that there are no outgoing edges, all of the Links are dead.
474 N->Ty.Ty = Type::VoidTy;
475 N->Ty.isArray = false;
477 // Merge the node types
478 NodeType |= N->NodeType;
479 N->NodeType = DEAD; // N is now a dead node.
481 // Merge the globals list...
482 if (!N->Globals.empty()) {
483 MergeSortedVectors(Globals, N->Globals);
485 // Delete the globals from the old node...
490 //===----------------------------------------------------------------------===//
491 // DSCallSite Implementation
492 //===----------------------------------------------------------------------===//
494 // Define here to avoid including iOther.h and BasicBlock.h in DSGraph.h
495 Function &DSCallSite::getCaller() const {
496 return *Inst->getParent()->getParent();
500 //===----------------------------------------------------------------------===//
501 // DSGraph Implementation
502 //===----------------------------------------------------------------------===//
504 DSGraph::DSGraph(const DSGraph &G) : Func(G.Func), GlobalsGraph(0) {
505 PrintAuxCalls = false;
506 std::map<const DSNode*, DSNodeHandle> NodeMap;
507 RetNode = cloneInto(G, ScalarMap, NodeMap);
510 DSGraph::DSGraph(const DSGraph &G,
511 std::map<const DSNode*, DSNodeHandle> &NodeMap)
512 : Func(G.Func), GlobalsGraph(0) {
513 PrintAuxCalls = false;
514 RetNode = cloneInto(G, ScalarMap, NodeMap);
517 DSGraph::~DSGraph() {
518 FunctionCalls.clear();
519 AuxFunctionCalls.clear();
523 // Drop all intra-node references, so that assertions don't fail...
524 std::for_each(Nodes.begin(), Nodes.end(),
525 std::mem_fun(&DSNode::dropAllReferences));
527 // Delete all of the nodes themselves...
528 std::for_each(Nodes.begin(), Nodes.end(), deleter<DSNode>);
531 // dump - Allow inspection of graph in a debugger.
532 void DSGraph::dump() const { print(std::cerr); }
535 /// remapLinks - Change all of the Links in the current node according to the
536 /// specified mapping.
538 void DSNode::remapLinks(std::map<const DSNode*, DSNodeHandle> &OldNodeMap) {
539 for (unsigned i = 0, e = Links.size(); i != e; ++i) {
540 DSNodeHandle &H = OldNodeMap[Links[i].getNode()];
541 Links[i].setNode(H.getNode());
542 Links[i].setOffset(Links[i].getOffset()+H.getOffset());
547 // cloneInto - Clone the specified DSGraph into the current graph, returning the
548 // Return node of the graph. The translated ScalarMap for the old function is
549 // filled into the OldValMap member. If StripAllocas is set to true, Alloca
550 // markers are removed from the graph, as the graph is being cloned into a
551 // calling function's graph.
553 DSNodeHandle DSGraph::cloneInto(const DSGraph &G,
554 std::map<Value*, DSNodeHandle> &OldValMap,
555 std::map<const DSNode*, DSNodeHandle> &OldNodeMap,
556 unsigned CloneFlags) {
557 assert(OldNodeMap.empty() && "Returned OldNodeMap should be empty!");
558 assert(&G != this && "Cannot clone graph into itself!");
560 unsigned FN = Nodes.size(); // First new node...
562 // Duplicate all of the nodes, populating the node map...
563 Nodes.reserve(FN+G.Nodes.size());
564 for (unsigned i = 0, e = G.Nodes.size(); i != e; ++i) {
565 DSNode *Old = G.Nodes[i];
566 DSNode *New = new DSNode(*Old);
567 New->NodeType &= ~DSNode::DEAD; // Clear dead flag...
568 Nodes.push_back(New);
569 OldNodeMap[Old] = New;
572 // Rewrite the links in the new nodes to point into the current graph now.
573 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
574 Nodes[i]->remapLinks(OldNodeMap);
576 // Remove alloca markers as specified
577 if (CloneFlags & StripAllocaBit)
578 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
579 Nodes[i]->NodeType &= ~DSNode::AllocaNode;
581 // Copy the value map... and merge all of the global nodes...
582 for (std::map<Value*, DSNodeHandle>::const_iterator I = G.ScalarMap.begin(),
583 E = G.ScalarMap.end(); I != E; ++I) {
584 DSNodeHandle &H = OldValMap[I->first];
585 DSNodeHandle &MappedNode = OldNodeMap[I->second.getNode()];
586 H.setNode(MappedNode.getNode());
587 H.setOffset(I->second.getOffset()+MappedNode.getOffset());
589 if (isa<GlobalValue>(I->first)) { // Is this a global?
590 std::map<Value*, DSNodeHandle>::iterator GVI = ScalarMap.find(I->first);
591 if (GVI != ScalarMap.end()) { // Is the global value in this fn already?
592 GVI->second.mergeWith(H);
594 ScalarMap[I->first] = H; // Add global pointer to this graph
599 if (!(CloneFlags & DontCloneCallNodes)) {
600 // Copy the function calls list...
601 unsigned FC = FunctionCalls.size(); // FirstCall
602 FunctionCalls.reserve(FC+G.FunctionCalls.size());
603 for (unsigned i = 0, ei = G.FunctionCalls.size(); i != ei; ++i)
604 FunctionCalls.push_back(DSCallSite(G.FunctionCalls[i], OldNodeMap));
607 if (!(CloneFlags & DontCloneAuxCallNodes)) {
608 // Copy the auxillary function calls list...
609 unsigned FC = AuxFunctionCalls.size(); // FirstCall
610 AuxFunctionCalls.reserve(FC+G.AuxFunctionCalls.size());
611 for (unsigned i = 0, ei = G.AuxFunctionCalls.size(); i != ei; ++i)
612 AuxFunctionCalls.push_back(DSCallSite(G.AuxFunctionCalls[i], OldNodeMap));
615 // Return the returned node pointer...
616 DSNodeHandle &MappedRet = OldNodeMap[G.RetNode.getNode()];
617 return DSNodeHandle(MappedRet.getNode(),
618 MappedRet.getOffset()+G.RetNode.getOffset());
621 /// mergeInGraph - The method is used for merging graphs together. If the
622 /// argument graph is not *this, it makes a clone of the specified graph, then
623 /// merges the nodes specified in the call site with the formal arguments in the
626 void DSGraph::mergeInGraph(DSCallSite &CS, const DSGraph &Graph,
627 unsigned CloneFlags) {
628 std::map<Value*, DSNodeHandle> OldValMap;
630 std::map<Value*, DSNodeHandle> *ScalarMap = &OldValMap;
632 // If this is not a recursive call, clone the graph into this graph...
633 if (&Graph != this) {
634 // Clone the callee's graph into the current graph, keeping
635 // track of where scalars in the old graph _used_ to point,
636 // and of the new nodes matching nodes of the old graph.
637 std::map<const DSNode*, DSNodeHandle> OldNodeMap;
639 // The clone call may invalidate any of the vectors in the data
640 // structure graph. Strip locals and don't copy the list of callers
641 RetVal = cloneInto(Graph, OldValMap, OldNodeMap, CloneFlags);
642 ScalarMap = &OldValMap;
644 RetVal = getRetNode();
645 ScalarMap = &getScalarMap();
648 // Merge the return value with the return value of the context...
649 RetVal.mergeWith(CS.getRetVal());
651 // Resolve all of the function arguments...
652 Function &F = Graph.getFunction();
653 Function::aiterator AI = F.abegin();
654 for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i, ++AI) {
655 // Advance the argument iterator to the first pointer argument...
656 while (!isPointerType(AI->getType())) {
660 std::cerr << "Bad call to Function: " << F.getName() << "\n";
662 assert(AI != F.aend() && "# Args provided is not # Args required!");
665 // Add the link from the argument scalar to the provided value
666 DSNodeHandle &NH = (*ScalarMap)[AI];
667 assert(NH.getNode() && "Pointer argument without scalarmap entry?");
668 NH.mergeWith(CS.getPtrArg(i));
673 // cloneGlobalInto - Clone the given global node and all its target links
674 // (and all their llinks, recursively).
676 DSNode *DSGraph::cloneGlobalInto(const DSNode *GNode) {
677 if (GNode == 0 || GNode->getGlobals().size() == 0) return 0;
679 // If a clone has already been created for GNode, return it.
680 DSNodeHandle& ValMapEntry = ScalarMap[GNode->getGlobals()[0]];
681 if (ValMapEntry != 0)
684 // Clone the node and update the ValMap.
685 DSNode* NewNode = new DSNode(*GNode);
686 ValMapEntry = NewNode; // j=0 case of loop below!
687 Nodes.push_back(NewNode);
688 for (unsigned j = 1, N = NewNode->getGlobals().size(); j < N; ++j)
689 ScalarMap[NewNode->getGlobals()[j]] = NewNode;
691 // Rewrite the links in the new node to point into the current graph.
692 for (unsigned j = 0, e = GNode->getNumLinks(); j != e; ++j)
693 NewNode->setLink(j, cloneGlobalInto(GNode->getLink(j)));
700 // markIncompleteNodes - Mark the specified node as having contents that are not
701 // known with the current analysis we have performed. Because a node makes all
702 // of the nodes it can reach imcomplete if the node itself is incomplete, we
703 // must recursively traverse the data structure graph, marking all reachable
704 // nodes as incomplete.
706 static void markIncompleteNode(DSNode *N) {
707 // Stop recursion if no node, or if node already marked...
708 if (N == 0 || (N->NodeType & DSNode::Incomplete)) return;
710 // Actually mark the node
711 N->NodeType |= DSNode::Incomplete;
713 // Recusively process children...
714 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
715 if (DSNode *DSN = N->getLink(i).getNode())
716 markIncompleteNode(DSN);
720 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
721 // modified by other functions that have not been resolved yet. This marks
722 // nodes that are reachable through three sources of "unknownness":
724 // Global Variables, Function Calls, and Incoming Arguments
726 // For any node that may have unknown components (because something outside the
727 // scope of current analysis may have modified it), the 'Incomplete' flag is
728 // added to the NodeType.
730 void DSGraph::markIncompleteNodes(bool markFormalArgs) {
731 // Mark any incoming arguments as incomplete...
732 if (markFormalArgs && Func)
733 for (Function::aiterator I = Func->abegin(), E = Func->aend(); I != E; ++I)
734 if (isPointerType(I->getType()) && ScalarMap.find(I) != ScalarMap.end())
735 markIncompleteNode(ScalarMap[I].getNode());
737 // Mark stuff passed into functions calls as being incomplete...
738 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
739 DSCallSite &Call = FunctionCalls[i];
740 // Then the return value is certainly incomplete!
741 markIncompleteNode(Call.getRetVal().getNode());
743 // All objects pointed to by function arguments are incomplete!
744 for (unsigned i = 0, e = Call.getNumPtrArgs(); i != e; ++i)
745 markIncompleteNode(Call.getPtrArg(i).getNode());
748 // Mark all of the nodes pointed to by global nodes as incomplete...
749 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
750 if (Nodes[i]->NodeType & DSNode::GlobalNode) {
751 DSNode *N = Nodes[i];
752 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
753 if (DSNode *DSN = N->getLink(i).getNode())
754 markIncompleteNode(DSN);
758 // removeRefsToGlobal - Helper function that removes globals from the
759 // ScalarMap so that the referrer count will go down to zero.
760 static void removeRefsToGlobal(DSNode* N,
761 std::map<Value*, DSNodeHandle> &ScalarMap) {
762 while (!N->getGlobals().empty()) {
763 GlobalValue *GV = N->getGlobals().back();
764 N->getGlobals().pop_back();
770 // isNodeDead - This method checks to see if a node is dead, and if it isn't, it
771 // checks to see if there are simple transformations that it can do to make it
774 bool DSGraph::isNodeDead(DSNode *N) {
775 // Is it a trivially dead shadow node?
776 return N->getReferrers().empty() && (N->NodeType & ~DSNode::DEAD) == 0;
779 static inline void killIfUselessEdge(DSNodeHandle &Edge) {
780 if (DSNode *N = Edge.getNode()) // Is there an edge?
781 if (N->getReferrers().size() == 1) // Does it point to a lonely node?
782 if ((N->NodeType & ~DSNode::Incomplete) == 0 && // No interesting info?
783 N->getType().Ty == Type::VoidTy && !N->isNodeCompletelyFolded())
784 Edge.setNode(0); // Kill the edge!
787 static inline bool nodeContainsExternalFunction(const DSNode *N) {
788 const std::vector<GlobalValue*> &Globals = N->getGlobals();
789 for (unsigned i = 0, e = Globals.size(); i != e; ++i)
790 if (Globals[i]->isExternal())
795 static void removeIdenticalCalls(vector<DSCallSite> &Calls,
796 const std::string &where) {
797 // Remove trivially identical function calls
798 unsigned NumFns = Calls.size();
799 std::sort(Calls.begin(), Calls.end()); // Sort by callee as primary key!
801 // Scan the call list cleaning it up as necessary...
802 DSNode *LastCalleeNode = 0;
803 unsigned NumDuplicateCalls = 0;
804 bool LastCalleeContainsExternalFunction = false;
805 for (unsigned i = 0, e = Calls.size(); i != e; ++i) {
806 DSCallSite &CS = Calls[i];
808 // If the return value or any arguments point to a void node with no
809 // information at all in it, and the call node is the only node to point
810 // to it, remove the edge to the node (killing the node).
812 killIfUselessEdge(CS.getRetVal());
813 for (unsigned a = 0, e = CS.getNumPtrArgs(); a != e; ++a)
814 killIfUselessEdge(CS.getPtrArg(a));
816 // If this call site calls the same function as the last call site, and if
817 // the function pointer contains an external function, this node will never
818 // be resolved. Merge the arguments of the call node because no information
821 if (CS.getCallee().getNode() == LastCalleeNode) {
823 if (NumDuplicateCalls == 1) {
824 LastCalleeContainsExternalFunction =
825 nodeContainsExternalFunction(LastCalleeNode);
828 if (LastCalleeContainsExternalFunction ||
829 // This should be more than enough context sensitivity!
830 // FIXME: Evaluate how many times this is tripped!
831 NumDuplicateCalls > 20) {
832 DSCallSite &OCS = Calls[i-1];
835 // The node will now be eliminated as a duplicate!
836 if (CS.getNumPtrArgs() < OCS.getNumPtrArgs())
838 else if (CS.getNumPtrArgs() > OCS.getNumPtrArgs())
842 LastCalleeNode = CS.getCallee().getNode();
843 NumDuplicateCalls = 0;
847 Calls.erase(std::unique(Calls.begin(), Calls.end()),
850 // Track the number of call nodes merged away...
851 NumCallNodesMerged += NumFns-Calls.size();
853 DEBUG(if (NumFns != Calls.size())
854 std::cerr << "Merged " << (NumFns-Calls.size())
855 << " call nodes in " << where << "\n";);
859 // removeTriviallyDeadNodes - After the graph has been constructed, this method
860 // removes all unreachable nodes that are created because they got merged with
861 // other nodes in the graph. These nodes will all be trivially unreachable, so
862 // we don't have to perform any non-trivial analysis here.
864 void DSGraph::removeTriviallyDeadNodes() {
865 removeIdenticalCalls(FunctionCalls, Func ? Func->getName() : "");
866 removeIdenticalCalls(AuxFunctionCalls, Func ? Func->getName() : "");
868 for (unsigned i = 0; i != Nodes.size(); ++i)
869 if (isNodeDead(Nodes[i])) { // This node is dead!
870 delete Nodes[i]; // Free memory...
871 Nodes.erase(Nodes.begin()+i--); // Remove from node list...
876 // markAlive - Simple graph walker that recursively traverses the graph, marking
877 // stuff to be alive.
879 static void markAlive(DSNode *N, std::set<DSNode*> &Alive) {
881 std::set<DSNode*>::iterator I = Alive.lower_bound(N);
882 if (I != Alive.end() && *I == N) return; // Already marked alive
883 Alive.insert(I, N); // Is alive now
885 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
886 markAlive(N->getLink(i).getNode(), Alive);
889 // markAliveIfCanReachAlive - Simple graph walker that recursively traverses the
890 // graph looking for a node that is marked alive. If the node is marked alive,
891 // the recursive unwind marks node alive that can point to the alive node. This
892 // is basically just a post-order traversal.
894 // This function returns true if the specified node is alive.
896 static bool markAliveIfCanReachAlive(DSNode *N, std::set<DSNode*> &Alive,
897 std::set<DSNode*> &Visited) {
898 if (N == 0) return false;
900 // If we know that this node is alive, return so!
901 if (Alive.count(N)) return true;
903 // Otherwise, we don't think the node is alive yet, check for infinite
905 std::set<DSNode*>::iterator VI = Visited.lower_bound(N);
906 if (VI != Visited.end() && *VI == N) return false; // Found a cycle
907 // No recursion, insert into Visited...
908 Visited.insert(VI, N);
910 if (N->NodeType & DSNode::GlobalNode)
911 return false; // Global nodes will be marked on their own
913 bool ChildrenAreAlive = false;
915 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
916 ChildrenAreAlive |= markAliveIfCanReachAlive(N->getLink(i).getNode(),
918 if (ChildrenAreAlive)
920 return ChildrenAreAlive;
923 static bool CallSiteUsesAliveArgs(DSCallSite &CS, std::set<DSNode*> &Alive,
924 std::set<DSNode*> &Visited) {
925 if (markAliveIfCanReachAlive(CS.getRetVal().getNode(), Alive, Visited) ||
926 markAliveIfCanReachAlive(CS.getCallee().getNode(), Alive, Visited))
928 for (unsigned j = 0, e = CS.getNumPtrArgs(); j != e; ++j)
929 if (markAliveIfCanReachAlive(CS.getPtrArg(j).getNode(), Alive, Visited))
934 static void markAlive(DSCallSite &CS, std::set<DSNode*> &Alive) {
935 markAlive(CS.getRetVal().getNode(), Alive);
936 markAlive(CS.getCallee().getNode(), Alive);
938 for (unsigned j = 0, e = CS.getNumPtrArgs(); j != e; ++j)
939 markAlive(CS.getPtrArg(j).getNode(), Alive);
942 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
943 // subgraphs that are unreachable. This often occurs because the data
944 // structure doesn't "escape" into it's caller, and thus should be eliminated
945 // from the caller's graph entirely. This is only appropriate to use when
948 void DSGraph::removeDeadNodes() {
949 // Reduce the amount of work we have to do...
950 removeTriviallyDeadNodes();
952 // FIXME: Merge nontrivially identical call nodes...
954 // Alive - a set that holds all nodes found to be reachable/alive.
955 std::set<DSNode*> Alive;
956 std::vector<std::pair<Value*, DSNode*> > GlobalNodes;
958 // Mark all nodes reachable by (non-global) scalar nodes as alive...
959 for (std::map<Value*, DSNodeHandle>::iterator I = ScalarMap.begin(),
960 E = ScalarMap.end(); I != E; ++I)
961 if (!isa<GlobalValue>(I->first)) // Don't mark globals!
962 markAlive(I->second.getNode(), Alive);
963 else // Keep track of global nodes
964 GlobalNodes.push_back(std::make_pair(I->first, I->second.getNode()));
966 // The return value is alive as well...
967 markAlive(RetNode.getNode(), Alive);
969 // If any global nodes points to a non-global that is "alive", the global is
970 // "alive" as well...
972 std::set<DSNode*> Visited;
973 for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
974 markAliveIfCanReachAlive(GlobalNodes[i].second, Alive, Visited);
976 std::vector<bool> FCallsAlive(FunctionCalls.size());
977 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
978 if (CallSiteUsesAliveArgs(FunctionCalls[i], Alive, Visited)) {
979 markAlive(FunctionCalls[i], Alive);
980 FCallsAlive[i] = true;
983 std::vector<bool> AuxFCallsAlive(AuxFunctionCalls.size());
984 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
985 if (CallSiteUsesAliveArgs(AuxFunctionCalls[i], Alive, Visited)) {
986 markAlive(AuxFunctionCalls[i], Alive);
987 AuxFCallsAlive[i] = true;
990 // Remove all dead function calls...
992 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
994 FunctionCalls[CurIdx++].swap(FunctionCalls[i]);
995 // Crop all the bad ones out...
996 FunctionCalls.erase(FunctionCalls.begin()+CurIdx, FunctionCalls.end());
998 // Remove all dead aux function calls...
1000 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
1001 if (AuxFCallsAlive[i])
1002 AuxFunctionCalls[CurIdx++].swap(AuxFunctionCalls[i]);
1003 // Crop all the bad ones out...
1004 AuxFunctionCalls.erase(AuxFunctionCalls.begin()+CurIdx,
1005 AuxFunctionCalls.end());
1008 // Remove all unreachable globals from the ScalarMap
1009 for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
1010 if (!Alive.count(GlobalNodes[i].second))
1011 ScalarMap.erase(GlobalNodes[i].first);
1013 // Loop over all unreachable nodes, dropping their references...
1014 vector<DSNode*> DeadNodes;
1015 DeadNodes.reserve(Nodes.size()); // Only one allocation is allowed.
1016 for (unsigned i = 0; i != Nodes.size(); ++i)
1017 if (!Alive.count(Nodes[i])) {
1018 DSNode *N = Nodes[i];
1019 Nodes.erase(Nodes.begin()+i--); // Erase node from alive list.
1020 DeadNodes.push_back(N); // Add node to our list of dead nodes
1021 N->dropAllReferences(); // Drop all outgoing edges
1024 // Delete all dead nodes...
1025 std::for_each(DeadNodes.begin(), DeadNodes.end(), deleter<DSNode>);
1029 //===----------------------------------------------------------------------===//
1030 // GlobalDSGraph Implementation
1031 //===----------------------------------------------------------------------===//
1034 // Bits used in the next function
1035 static const char ExternalTypeBits = DSNode::GlobalNode | DSNode::HeapNode;
1038 // GlobalDSGraph::cloneNodeInto - Clone a global node and all its externally
1039 // visible target links (and recursively their such links) into this graph.
1040 // NodeCache maps the node being cloned to its clone in the Globals graph,
1041 // in order to track cycles.
1042 // GlobalsAreFinal is a flag that says whether it is safe to assume that
1043 // an existing global node is complete. This is important to avoid
1044 // reinserting all globals when inserting Calls to functions.
1045 // This is a helper function for cloneGlobals and cloneCalls.
1047 DSNode* GlobalDSGraph::cloneNodeInto(DSNode *OldNode,
1048 std::map<const DSNode*, DSNode*> &NodeCache,
1049 bool GlobalsAreFinal) {
1050 if (OldNode == 0) return 0;
1052 // The caller should check this is an external node. Just more efficient...
1053 assert((OldNode->NodeType & ExternalTypeBits) && "Non-external node");
1055 // If a clone has already been created for OldNode, return it.
1056 DSNode*& CacheEntry = NodeCache[OldNode];
1057 if (CacheEntry != 0)
1060 // The result value...
1061 DSNode* NewNode = 0;
1063 // If nodes already exist for any of the globals of OldNode,
1064 // merge all such nodes together since they are merged in OldNode.
1065 // If ValueCacheIsFinal==true, look for an existing node that has
1066 // an identical list of globals and return it if it exists.
1068 for (unsigned j = 0, N = OldNode->getGlobals().size(); j != N; ++j)
1069 if (DSNode *PrevNode = ScalarMap[OldNode->getGlobals()[j]].getNode()) {
1071 NewNode = PrevNode; // first existing node found
1072 if (GlobalsAreFinal && j == 0)
1073 if (OldNode->getGlobals() == PrevNode->getGlobals()) {
1074 CacheEntry = NewNode;
1078 else if (NewNode != PrevNode) { // found another, different from prev
1079 // update ValMap *before* merging PrevNode into NewNode
1080 for (unsigned k = 0, NK = PrevNode->getGlobals().size(); k < NK; ++k)
1081 ScalarMap[PrevNode->getGlobals()[k]] = NewNode;
1082 NewNode->mergeWith(PrevNode);
1084 } else if (NewNode != 0) {
1085 ScalarMap[OldNode->getGlobals()[j]] = NewNode; // add the merged node
1088 // If no existing node was found, clone the node and update the ValMap.
1090 NewNode = new DSNode(*OldNode);
1091 Nodes.push_back(NewNode);
1092 for (unsigned j = 0, e = NewNode->getNumLinks(); j != e; ++j)
1093 NewNode->setLink(j, 0);
1094 for (unsigned j = 0, N = NewNode->getGlobals().size(); j < N; ++j)
1095 ScalarMap[NewNode->getGlobals()[j]] = NewNode;
1098 NewNode->NodeType |= OldNode->NodeType; // Markers may be different!
1100 // Add the entry to NodeCache
1101 CacheEntry = NewNode;
1103 // Rewrite the links in the new node to point into the current graph,
1104 // but only for links to external nodes. Set other links to NULL.
1105 for (unsigned j = 0, e = OldNode->getNumLinks(); j != e; ++j) {
1106 DSNode* OldTarget = OldNode->getLink(j);
1107 if (OldTarget && (OldTarget->NodeType & ExternalTypeBits)) {
1108 DSNode* NewLink = this->cloneNodeInto(OldTarget, NodeCache);
1109 if (NewNode->getLink(j))
1110 NewNode->getLink(j)->mergeWith(NewLink);
1112 NewNode->setLink(j, NewLink);
1116 // Remove all local markers
1117 NewNode->NodeType &= ~(DSNode::AllocaNode | DSNode::ScalarNode);
1123 // GlobalDSGraph::cloneCalls - Clone function calls and their visible target
1124 // links (and recursively their such links) into this graph.
1126 void GlobalDSGraph::cloneCalls(DSGraph& Graph) {
1127 std::map<const DSNode*, DSNode*> NodeCache;
1128 vector<DSCallSite >& FromCalls =Graph.FunctionCalls;
1130 FunctionCalls.reserve(FunctionCalls.size() + FromCalls.size());
1132 for (int i = 0, ei = FromCalls.size(); i < ei; ++i) {
1133 DSCallSite& callCopy = FunctionCalls.back();
1134 callCopy.reserve(FromCalls[i].size());
1135 for (unsigned j = 0, ej = FromCalls[i].size(); j != ej; ++j)
1137 ((FromCalls[i][j] && (FromCalls[i][j]->NodeType & ExternalTypeBits))
1138 ? cloneNodeInto(FromCalls[i][j], NodeCache, true)
1142 // remove trivially identical function calls
1143 removeIdenticalCalls(FunctionCalls, "Globals Graph");