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 std::map<const DSNode*, DSNodeHandle> NodeMap;
506 RetNode = cloneInto(G, ScalarMap, NodeMap);
509 DSGraph::DSGraph(const DSGraph &G,
510 std::map<const DSNode*, DSNodeHandle> &NodeMap)
511 : Func(G.Func), GlobalsGraph(0) {
512 RetNode = cloneInto(G, ScalarMap, NodeMap);
515 DSGraph::~DSGraph() {
516 FunctionCalls.clear();
517 AuxFunctionCalls.clear();
521 // Drop all intra-node references, so that assertions don't fail...
522 std::for_each(Nodes.begin(), Nodes.end(),
523 std::mem_fun(&DSNode::dropAllReferences));
525 // Delete all of the nodes themselves...
526 std::for_each(Nodes.begin(), Nodes.end(), deleter<DSNode>);
529 // dump - Allow inspection of graph in a debugger.
530 void DSGraph::dump() const { print(std::cerr); }
533 /// remapLinks - Change all of the Links in the current node according to the
534 /// specified mapping.
536 void DSNode::remapLinks(std::map<const DSNode*, DSNodeHandle> &OldNodeMap) {
537 for (unsigned i = 0, e = Links.size(); i != e; ++i) {
538 DSNodeHandle &H = OldNodeMap[Links[i].getNode()];
539 Links[i].setNode(H.getNode());
540 Links[i].setOffset(Links[i].getOffset()+H.getOffset());
545 // cloneInto - Clone the specified DSGraph into the current graph, returning the
546 // Return node of the graph. The translated ScalarMap for the old function is
547 // filled into the OldValMap member. If StripAllocas is set to true, Alloca
548 // markers are removed from the graph, as the graph is being cloned into a
549 // calling function's graph.
551 DSNodeHandle DSGraph::cloneInto(const DSGraph &G,
552 std::map<Value*, DSNodeHandle> &OldValMap,
553 std::map<const DSNode*, DSNodeHandle> &OldNodeMap,
554 unsigned CloneFlags) {
555 assert(OldNodeMap.empty() && "Returned OldNodeMap should be empty!");
556 assert(&G != this && "Cannot clone graph into itself!");
558 unsigned FN = Nodes.size(); // First new node...
560 // Duplicate all of the nodes, populating the node map...
561 Nodes.reserve(FN+G.Nodes.size());
562 for (unsigned i = 0, e = G.Nodes.size(); i != e; ++i) {
563 DSNode *Old = G.Nodes[i];
564 DSNode *New = new DSNode(*Old);
565 New->NodeType &= ~DSNode::DEAD; // Clear dead flag...
566 Nodes.push_back(New);
567 OldNodeMap[Old] = New;
570 // Rewrite the links in the new nodes to point into the current graph now.
571 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
572 Nodes[i]->remapLinks(OldNodeMap);
574 // Remove alloca markers as specified
575 if (CloneFlags & StripAllocaBit)
576 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
577 Nodes[i]->NodeType &= ~DSNode::AllocaNode;
579 // Copy the value map... and merge all of the global nodes...
580 for (std::map<Value*, DSNodeHandle>::const_iterator I = G.ScalarMap.begin(),
581 E = G.ScalarMap.end(); I != E; ++I) {
582 DSNodeHandle &H = OldValMap[I->first];
583 DSNodeHandle &MappedNode = OldNodeMap[I->second.getNode()];
584 H.setNode(MappedNode.getNode());
585 H.setOffset(I->second.getOffset()+MappedNode.getOffset());
587 if (isa<GlobalValue>(I->first)) { // Is this a global?
588 std::map<Value*, DSNodeHandle>::iterator GVI = ScalarMap.find(I->first);
589 if (GVI != ScalarMap.end()) { // Is the global value in this fn already?
590 GVI->second.mergeWith(H);
592 ScalarMap[I->first] = H; // Add global pointer to this graph
597 if (!(CloneFlags & DontCloneCallNodes)) {
598 // Copy the function calls list...
599 unsigned FC = FunctionCalls.size(); // FirstCall
600 FunctionCalls.reserve(FC+G.FunctionCalls.size());
601 for (unsigned i = 0, ei = G.FunctionCalls.size(); i != ei; ++i)
602 FunctionCalls.push_back(DSCallSite(G.FunctionCalls[i], OldNodeMap));
605 if (!(CloneFlags & DontCloneAuxCallNodes)) {
606 // Copy the auxillary function calls list...
607 unsigned FC = AuxFunctionCalls.size(); // FirstCall
608 AuxFunctionCalls.reserve(FC+G.AuxFunctionCalls.size());
609 for (unsigned i = 0, ei = G.AuxFunctionCalls.size(); i != ei; ++i)
610 AuxFunctionCalls.push_back(DSCallSite(G.AuxFunctionCalls[i], OldNodeMap));
613 // Return the returned node pointer...
614 DSNodeHandle &MappedRet = OldNodeMap[G.RetNode.getNode()];
615 return DSNodeHandle(MappedRet.getNode(),
616 MappedRet.getOffset()+G.RetNode.getOffset());
619 /// mergeInGraph - The method is used for merging graphs together. If the
620 /// argument graph is not *this, it makes a clone of the specified graph, then
621 /// merges the nodes specified in the call site with the formal arguments in the
624 void DSGraph::mergeInGraph(DSCallSite &CS, const DSGraph &Graph,
625 unsigned CloneFlags) {
626 std::map<Value*, DSNodeHandle> OldValMap;
628 std::map<Value*, DSNodeHandle> *ScalarMap = &OldValMap;
630 // If this is not a recursive call, clone the graph into this graph...
631 if (&Graph != this) {
632 // Clone the callee's graph into the current graph, keeping
633 // track of where scalars in the old graph _used_ to point,
634 // and of the new nodes matching nodes of the old graph.
635 std::map<const DSNode*, DSNodeHandle> OldNodeMap;
637 // The clone call may invalidate any of the vectors in the data
638 // structure graph. Strip locals and don't copy the list of callers
639 RetVal = cloneInto(Graph, OldValMap, OldNodeMap, CloneFlags);
640 ScalarMap = &OldValMap;
642 RetVal = getRetNode();
643 ScalarMap = &getScalarMap();
646 // Merge the return value with the return value of the context...
647 RetVal.mergeWith(CS.getRetVal());
649 // Resolve all of the function arguments...
650 Function &F = Graph.getFunction();
651 Function::aiterator AI = F.abegin();
652 for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i, ++AI) {
653 // Advance the argument iterator to the first pointer argument...
654 while (!isPointerType(AI->getType())) {
658 std::cerr << "Bad call to Function: " << F.getName() << "\n";
660 assert(AI != F.aend() && "# Args provided is not # Args required!");
663 // Add the link from the argument scalar to the provided value
664 DSNodeHandle &NH = (*ScalarMap)[AI];
665 assert(NH.getNode() && "Pointer argument without scalarmap entry?");
666 NH.mergeWith(CS.getPtrArg(i));
671 // cloneGlobalInto - Clone the given global node and all its target links
672 // (and all their llinks, recursively).
674 DSNode *DSGraph::cloneGlobalInto(const DSNode *GNode) {
675 if (GNode == 0 || GNode->getGlobals().size() == 0) return 0;
677 // If a clone has already been created for GNode, return it.
678 DSNodeHandle& ValMapEntry = ScalarMap[GNode->getGlobals()[0]];
679 if (ValMapEntry != 0)
682 // Clone the node and update the ValMap.
683 DSNode* NewNode = new DSNode(*GNode);
684 ValMapEntry = NewNode; // j=0 case of loop below!
685 Nodes.push_back(NewNode);
686 for (unsigned j = 1, N = NewNode->getGlobals().size(); j < N; ++j)
687 ScalarMap[NewNode->getGlobals()[j]] = NewNode;
689 // Rewrite the links in the new node to point into the current graph.
690 for (unsigned j = 0, e = GNode->getNumLinks(); j != e; ++j)
691 NewNode->setLink(j, cloneGlobalInto(GNode->getLink(j)));
698 // markIncompleteNodes - Mark the specified node as having contents that are not
699 // known with the current analysis we have performed. Because a node makes all
700 // of the nodes it can reach imcomplete if the node itself is incomplete, we
701 // must recursively traverse the data structure graph, marking all reachable
702 // nodes as incomplete.
704 static void markIncompleteNode(DSNode *N) {
705 // Stop recursion if no node, or if node already marked...
706 if (N == 0 || (N->NodeType & DSNode::Incomplete)) return;
708 // Actually mark the node
709 N->NodeType |= DSNode::Incomplete;
711 // Recusively process children...
712 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
713 if (DSNode *DSN = N->getLink(i).getNode())
714 markIncompleteNode(DSN);
718 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
719 // modified by other functions that have not been resolved yet. This marks
720 // nodes that are reachable through three sources of "unknownness":
722 // Global Variables, Function Calls, and Incoming Arguments
724 // For any node that may have unknown components (because something outside the
725 // scope of current analysis may have modified it), the 'Incomplete' flag is
726 // added to the NodeType.
728 void DSGraph::markIncompleteNodes(bool markFormalArgs) {
729 // Mark any incoming arguments as incomplete...
730 if (markFormalArgs && Func)
731 for (Function::aiterator I = Func->abegin(), E = Func->aend(); I != E; ++I)
732 if (isPointerType(I->getType()) && ScalarMap.find(I) != ScalarMap.end())
733 markIncompleteNode(ScalarMap[I].getNode());
735 // Mark stuff passed into functions calls as being incomplete...
736 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
737 DSCallSite &Call = FunctionCalls[i];
738 // Then the return value is certainly incomplete!
739 markIncompleteNode(Call.getRetVal().getNode());
741 // All objects pointed to by function arguments are incomplete though!
742 for (unsigned i = 0, e = Call.getNumPtrArgs(); i != e; ++i)
743 markIncompleteNode(Call.getPtrArg(i).getNode());
746 // Mark all of the nodes pointed to by global nodes as incomplete...
747 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
748 if (Nodes[i]->NodeType & DSNode::GlobalNode) {
749 DSNode *N = Nodes[i];
750 // FIXME: Make more efficient by looking over Links directly
751 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
752 if (DSNode *DSN = N->getLink(i).getNode())
753 markIncompleteNode(DSN);
757 // removeRefsToGlobal - Helper function that removes globals from the
758 // ScalarMap so that the referrer count will go down to zero.
759 static void removeRefsToGlobal(DSNode* N,
760 std::map<Value*, DSNodeHandle> &ScalarMap) {
761 while (!N->getGlobals().empty()) {
762 GlobalValue *GV = N->getGlobals().back();
763 N->getGlobals().pop_back();
769 // isNodeDead - This method checks to see if a node is dead, and if it isn't, it
770 // checks to see if there are simple transformations that it can do to make it
773 bool DSGraph::isNodeDead(DSNode *N) {
774 // Is it a trivially dead shadow node...
775 if (N->getReferrers().empty() && (N->NodeType & ~DSNode::DEAD) == 0)
778 // Is it a function node or some other trivially unused global?
779 if ((N->NodeType & ~DSNode::GlobalNode) == 0 && N->getSize() == 0 &&
780 N->getReferrers().size() == N->getGlobals().size()) {
782 // Remove the globals from the ScalarMap, so that the referrer count will go
784 removeRefsToGlobal(N, ScalarMap);
785 assert(N->getReferrers().empty() && "Referrers should all be gone now!");
792 static void removeIdenticalCalls(vector<DSCallSite> &Calls,
793 const std::string &where) {
794 // Remove trivially identical function calls
795 unsigned NumFns = Calls.size();
796 std::sort(Calls.begin(), Calls.end());
797 Calls.erase(std::unique(Calls.begin(), Calls.end()),
800 // Track the number of call nodes merged away...
801 NumCallNodesMerged += NumFns-Calls.size();
803 DEBUG(if (NumFns != Calls.size())
804 std::cerr << "Merged " << (NumFns-Calls.size())
805 << " call nodes in " << where << "\n";);
808 // removeTriviallyDeadNodes - After the graph has been constructed, this method
809 // removes all unreachable nodes that are created because they got merged with
810 // other nodes in the graph. These nodes will all be trivially unreachable, so
811 // we don't have to perform any non-trivial analysis here.
813 void DSGraph::removeTriviallyDeadNodes() {
814 for (unsigned i = 0; i != Nodes.size(); ++i)
815 if (!(Nodes[i]->NodeType & DSNode::GlobalNode))
816 if (isNodeDead(Nodes[i])) { // This node is dead!
817 delete Nodes[i]; // Free memory...
818 Nodes.erase(Nodes.begin()+i--); // Remove from node list...
821 removeIdenticalCalls(FunctionCalls, Func ? Func->getName() : "");
825 // markAlive - Simple graph walker that recursively traverses the graph, marking
826 // stuff to be alive.
828 static void markAlive(DSNode *N, std::set<DSNode*> &Alive) {
832 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
833 if (DSNode *DSN = N->getLink(i).getNode())
834 if (!Alive.count(DSN))
835 markAlive(DSN, Alive);
838 static bool checkGlobalAlive(DSNode *N, std::set<DSNode*> &Alive,
839 std::set<DSNode*> &Visiting) {
840 if (N == 0) return false;
842 if (Visiting.count(N)) return false; // terminate recursion on a cycle
845 // If any immediate successor is alive, N is alive
846 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
847 if (DSNode *DSN = N->getLink(i).getNode())
848 if (Alive.count(DSN)) {
853 // Else if any successor reaches a live node, N is alive
854 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
855 if (DSNode *DSN = N->getLink(i).getNode())
856 if (checkGlobalAlive(DSN, Alive, Visiting)) {
857 Visiting.erase(N); return true;
865 // markGlobalsIteration - Recursive helper function for markGlobalsAlive().
866 // This would be unnecessary if function calls were real nodes! In that case,
867 // the simple iterative loop in the first few lines below suffice.
869 static void markGlobalsIteration(std::set<DSNode*>& GlobalNodes,
870 vector<DSCallSite> &Calls,
871 std::set<DSNode*> &Alive,
874 // Iterate, marking globals or cast nodes alive until no new live nodes
875 // are added to Alive
876 std::set<DSNode*> Visiting; // Used to identify cycles
877 std::set<DSNode*>::iterator I = GlobalNodes.begin(), E = GlobalNodes.end();
878 for (size_t liveCount = 0; liveCount < Alive.size(); ) {
879 liveCount = Alive.size();
881 if (Alive.count(*I) == 0) {
883 if (checkGlobalAlive(*I, Alive, Visiting))
884 markAlive(*I, Alive);
888 // Find function calls with some dead and some live nodes.
889 // Since all call nodes must be live if any one is live, we have to mark
890 // all nodes of the call as live and continue the iteration (via recursion).
892 bool Recurse = false;
893 for (unsigned i = 0, ei = Calls.size(); i < ei; ++i) {
894 bool CallIsDead = true, CallHasDeadArg = false;
895 DSCallSite &CS = Calls[i];
896 for (unsigned j = 0, ej = CS.getNumPtrArgs(); j != ej; ++j)
897 if (DSNode *N = CS.getPtrArg(j).getNode()) {
898 bool ArgIsDead = !Alive.count(N);
899 CallHasDeadArg |= ArgIsDead;
900 CallIsDead &= ArgIsDead;
903 if (DSNode *N = CS.getRetVal().getNode()) {
904 bool RetIsDead = !Alive.count(N);
905 CallHasDeadArg |= RetIsDead;
906 CallIsDead &= RetIsDead;
909 DSNode *N = CS.getCallee().getNode();
910 bool FnIsDead = !Alive.count(N);
911 CallHasDeadArg |= FnIsDead;
912 CallIsDead &= FnIsDead;
914 if (!CallIsDead && CallHasDeadArg) {
915 // Some node in this call is live and another is dead.
916 // Mark all nodes of call as live and iterate once more.
918 for (unsigned j = 0, ej = CS.getNumPtrArgs(); j != ej; ++j)
919 markAlive(CS.getPtrArg(j).getNode(), Alive);
920 markAlive(CS.getRetVal().getNode(), Alive);
921 markAlive(CS.getCallee().getNode(), Alive);
925 markGlobalsIteration(GlobalNodes, Calls, Alive, FilterCalls);
930 // markGlobalsAlive - Mark global nodes and cast nodes alive if they
931 // can reach any other live node. Since this can produce new live nodes,
932 // we use a simple iterative algorithm.
934 static void markGlobalsAlive(DSGraph &G, std::set<DSNode*> &Alive,
936 // Add global and cast nodes to a set so we don't walk all nodes every time
937 std::set<DSNode*> GlobalNodes;
938 for (unsigned i = 0, e = G.getNodes().size(); i != e; ++i)
939 if (G.getNodes()[i]->NodeType & DSNode::GlobalNode)
940 GlobalNodes.insert(G.getNodes()[i]);
942 // Add all call nodes to the same set
943 vector<DSCallSite> &Calls = G.getAuxFunctionCalls();
945 for (unsigned i = 0, e = Calls.size(); i != e; ++i) {
946 for (unsigned j = 0, e = Calls[i].getNumPtrArgs(); j != e; ++j)
947 if (DSNode *N = Calls[i].getPtrArg(j).getNode())
948 GlobalNodes.insert(N);
949 if (DSNode *N = Calls[i].getRetVal().getNode())
950 GlobalNodes.insert(N);
951 if (DSNode *N = Calls[i].getCallee().getNode())
952 GlobalNodes.insert(N);
956 // Iterate and recurse until no new live node are discovered.
957 // This would be a simple iterative loop if function calls were real nodes!
958 markGlobalsIteration(GlobalNodes, Calls, Alive, FilterCalls);
960 // Free up references to dead globals from the ScalarMap
961 std::set<DSNode*>::iterator I = GlobalNodes.begin(), E = GlobalNodes.end();
963 if (Alive.count(*I) == 0)
964 removeRefsToGlobal(*I, G.getScalarMap());
966 // Delete dead function calls
968 for (int ei = Calls.size(), i = ei-1; i >= 0; --i) {
969 bool CallIsDead = true;
970 for (unsigned j = 0, ej = Calls[i].getNumPtrArgs();
971 CallIsDead && j != ej; ++j)
972 CallIsDead = Alive.count(Calls[i].getPtrArg(j).getNode()) == 0;
974 Calls.erase(Calls.begin() + i); // remove the call entirely
978 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
979 // subgraphs that are unreachable. This often occurs because the data
980 // structure doesn't "escape" into it's caller, and thus should be eliminated
981 // from the caller's graph entirely. This is only appropriate to use when
984 void DSGraph::removeDeadNodes() {
985 // Reduce the amount of work we have to do...
986 removeTriviallyDeadNodes();
988 // FIXME: Merge nontrivially identical call nodes...
990 // Alive - a set that holds all nodes found to be reachable/alive.
991 std::set<DSNode*> Alive;
993 // If KeepCalls, mark all nodes reachable by call nodes as alive...
994 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
995 for (unsigned j = 0, e = FunctionCalls[i].getNumPtrArgs(); j != e; ++j)
996 markAlive(FunctionCalls[i].getPtrArg(j).getNode(), Alive);
997 markAlive(FunctionCalls[i].getRetVal().getNode(), Alive);
998 markAlive(FunctionCalls[i].getCallee().getNode(), Alive);
1000 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i) {
1001 for (unsigned j = 0, e = AuxFunctionCalls[i].getNumPtrArgs(); j != e; ++j)
1002 markAlive(AuxFunctionCalls[i].getPtrArg(j).getNode(), Alive);
1003 markAlive(AuxFunctionCalls[i].getRetVal().getNode(), Alive);
1004 markAlive(AuxFunctionCalls[i].getCallee().getNode(), Alive);
1007 // Mark all nodes reachable by scalar nodes as alive...
1008 for (std::map<Value*, DSNodeHandle>::iterator I = ScalarMap.begin(),
1009 E = ScalarMap.end(); I != E; ++I)
1010 markAlive(I->second.getNode(), Alive);
1012 // The return value is alive as well...
1013 markAlive(RetNode.getNode(), Alive);
1015 // Loop over all unreachable nodes, dropping their references...
1016 vector<DSNode*> DeadNodes;
1017 DeadNodes.reserve(Nodes.size()); // Only one allocation is allowed.
1018 for (unsigned i = 0; i != Nodes.size(); ++i)
1019 if (!Alive.count(Nodes[i])) {
1020 DSNode *N = Nodes[i];
1021 Nodes.erase(Nodes.begin()+i--); // Erase node from alive list.
1022 DeadNodes.push_back(N); // Add node to our list of dead nodes
1023 N->dropAllReferences(); // Drop all outgoing edges
1026 // Delete all dead nodes...
1027 std::for_each(DeadNodes.begin(), DeadNodes.end(), deleter<DSNode>);
1031 //===----------------------------------------------------------------------===//
1032 // GlobalDSGraph Implementation
1033 //===----------------------------------------------------------------------===//
1036 // Bits used in the next function
1037 static const char ExternalTypeBits = DSNode::GlobalNode | DSNode::HeapNode;
1040 // GlobalDSGraph::cloneNodeInto - Clone a global node and all its externally
1041 // visible target links (and recursively their such links) into this graph.
1042 // NodeCache maps the node being cloned to its clone in the Globals graph,
1043 // in order to track cycles.
1044 // GlobalsAreFinal is a flag that says whether it is safe to assume that
1045 // an existing global node is complete. This is important to avoid
1046 // reinserting all globals when inserting Calls to functions.
1047 // This is a helper function for cloneGlobals and cloneCalls.
1049 DSNode* GlobalDSGraph::cloneNodeInto(DSNode *OldNode,
1050 std::map<const DSNode*, DSNode*> &NodeCache,
1051 bool GlobalsAreFinal) {
1052 if (OldNode == 0) return 0;
1054 // The caller should check this is an external node. Just more efficient...
1055 assert((OldNode->NodeType & ExternalTypeBits) && "Non-external node");
1057 // If a clone has already been created for OldNode, return it.
1058 DSNode*& CacheEntry = NodeCache[OldNode];
1059 if (CacheEntry != 0)
1062 // The result value...
1063 DSNode* NewNode = 0;
1065 // If nodes already exist for any of the globals of OldNode,
1066 // merge all such nodes together since they are merged in OldNode.
1067 // If ValueCacheIsFinal==true, look for an existing node that has
1068 // an identical list of globals and return it if it exists.
1070 for (unsigned j = 0, N = OldNode->getGlobals().size(); j != N; ++j)
1071 if (DSNode *PrevNode = ScalarMap[OldNode->getGlobals()[j]].getNode()) {
1073 NewNode = PrevNode; // first existing node found
1074 if (GlobalsAreFinal && j == 0)
1075 if (OldNode->getGlobals() == PrevNode->getGlobals()) {
1076 CacheEntry = NewNode;
1080 else if (NewNode != PrevNode) { // found another, different from prev
1081 // update ValMap *before* merging PrevNode into NewNode
1082 for (unsigned k = 0, NK = PrevNode->getGlobals().size(); k < NK; ++k)
1083 ScalarMap[PrevNode->getGlobals()[k]] = NewNode;
1084 NewNode->mergeWith(PrevNode);
1086 } else if (NewNode != 0) {
1087 ScalarMap[OldNode->getGlobals()[j]] = NewNode; // add the merged node
1090 // If no existing node was found, clone the node and update the ValMap.
1092 NewNode = new DSNode(*OldNode);
1093 Nodes.push_back(NewNode);
1094 for (unsigned j = 0, e = NewNode->getNumLinks(); j != e; ++j)
1095 NewNode->setLink(j, 0);
1096 for (unsigned j = 0, N = NewNode->getGlobals().size(); j < N; ++j)
1097 ScalarMap[NewNode->getGlobals()[j]] = NewNode;
1100 NewNode->NodeType |= OldNode->NodeType; // Markers may be different!
1102 // Add the entry to NodeCache
1103 CacheEntry = NewNode;
1105 // Rewrite the links in the new node to point into the current graph,
1106 // but only for links to external nodes. Set other links to NULL.
1107 for (unsigned j = 0, e = OldNode->getNumLinks(); j != e; ++j) {
1108 DSNode* OldTarget = OldNode->getLink(j);
1109 if (OldTarget && (OldTarget->NodeType & ExternalTypeBits)) {
1110 DSNode* NewLink = this->cloneNodeInto(OldTarget, NodeCache);
1111 if (NewNode->getLink(j))
1112 NewNode->getLink(j)->mergeWith(NewLink);
1114 NewNode->setLink(j, NewLink);
1118 // Remove all local markers
1119 NewNode->NodeType &= ~(DSNode::AllocaNode | DSNode::ScalarNode);
1125 // GlobalDSGraph::cloneCalls - Clone function calls and their visible target
1126 // links (and recursively their such links) into this graph.
1128 void GlobalDSGraph::cloneCalls(DSGraph& Graph) {
1129 std::map<const DSNode*, DSNode*> NodeCache;
1130 vector<DSCallSite >& FromCalls =Graph.FunctionCalls;
1132 FunctionCalls.reserve(FunctionCalls.size() + FromCalls.size());
1134 for (int i = 0, ei = FromCalls.size(); i < ei; ++i) {
1135 DSCallSite& callCopy = FunctionCalls.back();
1136 callCopy.reserve(FromCalls[i].size());
1137 for (unsigned j = 0, ej = FromCalls[i].size(); j != ej; ++j)
1139 ((FromCalls[i][j] && (FromCalls[i][j]->NodeType & ExternalTypeBits))
1140 ? cloneNodeInto(FromCalls[i][j], NodeCache, true)
1144 // remove trivially identical function calls
1145 removeIdenticalCalls(FunctionCalls, "Globals Graph");