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"
14 #include "Support/Timer.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...
84 // Loop over all of our referrers, making them point to our zero bytes of
86 for (vector<DSNodeHandle*>::iterator I = Referrers.begin(), E=Referrers.end();
90 // If we have links, merge all of our outgoing links together...
91 for (unsigned i = 1, e = Links.size(); i < e; ++i)
92 Links[0].mergeWith(Links[i]);
96 /// isNodeCompletelyFolded - Return true if this node has been completely
97 /// folded down to something that can never be expanded, effectively losing
98 /// all of the field sensitivity that may be present in the node.
100 bool DSNode::isNodeCompletelyFolded() const {
101 return getSize() == 1 && Ty == Type::VoidTy && isArray();
105 /// mergeTypeInfo - This method merges the specified type into the current node
106 /// at the specified offset. This may update the current node's type record if
107 /// this gives more information to the node, it may do nothing to the node if
108 /// this information is already known, or it may merge the node completely (and
109 /// return true) if the information is incompatible with what is already known.
111 /// This method returns true if the node is completely folded, otherwise false.
113 bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset) {
114 // Check to make sure the Size member is up-to-date. Size can be one of the
116 // Size = 0, Ty = Void: Nothing is known about this node.
117 // Size = 0, Ty = FnTy: FunctionPtr doesn't have a size, so we use zero
118 // Size = 1, Ty = Void, Array = 1: The node is collapsed
119 // Otherwise, sizeof(Ty) = Size
121 assert(((Size == 0 && Ty == Type::VoidTy && !isArray()) ||
122 (Size == 0 && !Ty->isSized() && !isArray()) ||
123 (Size == 1 && Ty == Type::VoidTy && isArray()) ||
124 (Size == 0 && !Ty->isSized() && !isArray()) ||
125 (TD.getTypeSize(Ty) == Size)) &&
126 "Size member of DSNode doesn't match the type structure!");
127 assert(NewTy != Type::VoidTy && "Cannot merge void type into DSNode!");
129 if (Offset == 0 && NewTy == Ty)
130 return false; // This should be a common case, handle it efficiently
132 // Return true immediately if the node is completely folded.
133 if (isNodeCompletelyFolded()) return true;
135 // If this is an array type, eliminate the outside arrays because they won't
136 // be used anyway. This greatly reduces the size of large static arrays used
137 // as global variables, for example.
139 bool WillBeArray = false;
140 while (const ArrayType *AT = dyn_cast<ArrayType>(NewTy)) {
141 // FIXME: we might want to keep small arrays, but must be careful about
142 // things like: [2 x [10000 x int*]]
143 NewTy = AT->getElementType();
147 // Figure out how big the new type we're merging in is...
148 unsigned NewTySize = NewTy->isSized() ? TD.getTypeSize(NewTy) : 0;
150 // Otherwise check to see if we can fold this type into the current node. If
151 // we can't, we fold the node completely, if we can, we potentially update our
154 if (Ty == Type::VoidTy) {
155 // If this is the first type that this node has seen, just accept it without
157 assert(Offset == 0 && "Cannot have an offset into a void node!");
158 assert(!isArray() && "This shouldn't happen!");
161 if (WillBeArray) NodeType |= Array;
164 // Calculate the number of outgoing links from this node.
165 Links.resize((Size+DS::PointerSize-1) >> DS::PointerShift);
169 // Handle node expansion case here...
170 if (Offset+NewTySize > Size) {
171 // It is illegal to grow this node if we have treated it as an array of
174 foldNodeCompletely();
178 if (Offset) { // We could handle this case, but we don't for now...
179 DEBUG(std::cerr << "UNIMP: Trying to merge a growth type into "
180 << "offset != 0: Collapsing!\n");
181 foldNodeCompletely();
185 // Okay, the situation is nice and simple, we are trying to merge a type in
186 // at offset 0 that is bigger than our current type. Implement this by
187 // switching to the new type and then merge in the smaller one, which should
188 // hit the other code path here. If the other code path decides it's not
189 // ok, it will collapse the node as appropriate.
191 const Type *OldTy = Ty;
194 if (WillBeArray) NodeType |= Array;
197 // Must grow links to be the appropriate size...
198 Links.resize((Size+DS::PointerSize-1) >> DS::PointerShift);
200 // Merge in the old type now... which is guaranteed to be smaller than the
202 return mergeTypeInfo(OldTy, 0);
205 assert(Offset <= Size &&
206 "Cannot merge something into a part of our type that doesn't exist!");
208 // Find the section of Ty that NewTy overlaps with... first we find the
209 // type that starts at offset Offset.
212 const Type *SubType = Ty;
214 assert(Offset-O < TD.getTypeSize(SubType) && "Offset out of range!");
216 switch (SubType->getPrimitiveID()) {
217 case Type::StructTyID: {
218 const StructType *STy = cast<StructType>(SubType);
219 const StructLayout &SL = *TD.getStructLayout(STy);
221 unsigned i = 0, e = SL.MemberOffsets.size();
222 for (; i+1 < e && SL.MemberOffsets[i+1] <= Offset-O; ++i)
225 // The offset we are looking for must be in the i'th element...
226 SubType = STy->getElementTypes()[i];
227 O += SL.MemberOffsets[i];
230 case Type::ArrayTyID: {
231 SubType = cast<ArrayType>(SubType)->getElementType();
232 unsigned ElSize = TD.getTypeSize(SubType);
233 unsigned Remainder = (Offset-O) % ElSize;
234 O = Offset-Remainder;
238 assert(0 && "Unknown type!");
242 assert(O == Offset && "Could not achieve the correct offset!");
244 // If we found our type exactly, early exit
245 if (SubType == NewTy) return false;
247 // Okay, so we found the leader type at the offset requested. Search the list
248 // of types that starts at this offset. If SubType is currently an array or
249 // structure, the type desired may actually be the first element of the
252 unsigned SubTypeSize = SubType->isSized() ? TD.getTypeSize(SubType) : 0;
253 unsigned PadSize = SubTypeSize; // Size, including pad memory which is ignored
254 while (SubType != NewTy) {
255 const Type *NextSubType = 0;
256 unsigned NextSubTypeSize = 0;
257 unsigned NextPadSize = 0;
258 switch (SubType->getPrimitiveID()) {
259 case Type::StructTyID: {
260 const StructType *STy = cast<StructType>(SubType);
261 const StructLayout &SL = *TD.getStructLayout(STy);
262 if (SL.MemberOffsets.size() > 1)
263 NextPadSize = SL.MemberOffsets[1];
265 NextPadSize = SubTypeSize;
266 NextSubType = STy->getElementTypes()[0];
267 NextSubTypeSize = TD.getTypeSize(NextSubType);
270 case Type::ArrayTyID:
271 NextSubType = cast<ArrayType>(SubType)->getElementType();
272 NextSubTypeSize = TD.getTypeSize(NextSubType);
273 NextPadSize = NextSubTypeSize;
279 if (NextSubType == 0)
280 break; // In the default case, break out of the loop
282 if (NextPadSize < NewTySize)
283 break; // Don't allow shrinking to a smaller type than NewTySize
284 SubType = NextSubType;
285 SubTypeSize = NextSubTypeSize;
286 PadSize = NextPadSize;
289 // If we found the type exactly, return it...
290 if (SubType == NewTy)
293 // Check to see if we have a compatible, but different type...
294 if (NewTySize == SubTypeSize) {
295 // Check to see if this type is obviously convertable... int -> uint f.e.
296 if (NewTy->isLosslesslyConvertableTo(SubType))
299 // Check to see if we have a pointer & integer mismatch going on here,
300 // loading a pointer as a long, for example.
302 if (SubType->isInteger() && isa<PointerType>(NewTy) ||
303 NewTy->isInteger() && isa<PointerType>(SubType))
305 } else if (NewTySize > SubTypeSize && NewTySize <= PadSize) {
306 // We are accessing the field, plus some structure padding. Ignore the
307 // structure padding.
312 DEBUG(std::cerr << "MergeTypeInfo Folding OrigTy: " << Ty
313 << "\n due to:" << NewTy << " @ " << Offset << "!\n"
314 << "SubType: " << SubType << "\n\n");
316 foldNodeCompletely();
322 // addEdgeTo - Add an edge from the current node to the specified node. This
323 // can cause merging of nodes in the graph.
325 void DSNode::addEdgeTo(unsigned Offset, const DSNodeHandle &NH) {
326 if (NH.getNode() == 0) return; // Nothing to do
328 DSNodeHandle &ExistingEdge = getLink(Offset);
329 if (ExistingEdge.getNode()) {
330 // Merge the two nodes...
331 ExistingEdge.mergeWith(NH);
332 } else { // No merging to perform...
333 setLink(Offset, NH); // Just force a link in there...
338 // MergeSortedVectors - Efficiently merge a vector into another vector where
339 // duplicates are not allowed and both are sorted. This assumes that 'T's are
340 // efficiently copyable and have sane comparison semantics.
342 static void MergeSortedVectors(vector<GlobalValue*> &Dest,
343 const vector<GlobalValue*> &Src) {
344 // By far, the most common cases will be the simple ones. In these cases,
345 // avoid having to allocate a temporary vector...
347 if (Src.empty()) { // Nothing to merge in...
349 } else if (Dest.empty()) { // Just copy the result in...
351 } else if (Src.size() == 1) { // Insert a single element...
352 const GlobalValue *V = Src[0];
353 vector<GlobalValue*>::iterator I =
354 std::lower_bound(Dest.begin(), Dest.end(), V);
355 if (I == Dest.end() || *I != Src[0]) // If not already contained...
356 Dest.insert(I, Src[0]);
357 } else if (Dest.size() == 1) {
358 GlobalValue *Tmp = Dest[0]; // Save value in temporary...
359 Dest = Src; // Copy over list...
360 vector<GlobalValue*>::iterator I =
361 std::lower_bound(Dest.begin(), Dest.end(), Tmp);
362 if (I == Dest.end() || *I != Tmp) // If not already contained...
366 // Make a copy to the side of Dest...
367 vector<GlobalValue*> Old(Dest);
369 // Make space for all of the type entries now...
370 Dest.resize(Dest.size()+Src.size());
372 // Merge the two sorted ranges together... into Dest.
373 std::merge(Old.begin(), Old.end(), Src.begin(), Src.end(), Dest.begin());
375 // Now erase any duplicate entries that may have accumulated into the
376 // vectors (because they were in both of the input sets)
377 Dest.erase(std::unique(Dest.begin(), Dest.end()), Dest.end());
382 // MergeNodes() - Helper function for DSNode::mergeWith().
383 // This function does the hard work of merging two nodes, CurNodeH
384 // and NH after filtering out trivial cases and making sure that
385 // CurNodeH.offset >= NH.offset.
388 // Since merging may cause either node to go away, we must always
389 // use the node-handles to refer to the nodes. These node handles are
390 // automatically updated during merging, so will always provide access
391 // to the correct node after a merge.
393 void DSNode::MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH) {
394 assert(CurNodeH.getOffset() >= NH.getOffset() &&
395 "This should have been enforced in the caller.");
397 // Now we know that Offset >= NH.Offset, so convert it so our "Offset" (with
398 // respect to NH.Offset) is now zero. NOffset is the distance from the base
399 // of our object that N starts from.
401 unsigned NOffset = CurNodeH.getOffset()-NH.getOffset();
402 unsigned NSize = NH.getNode()->getSize();
404 // Merge the type entries of the two nodes together...
405 if (NH.getNode()->Ty != Type::VoidTy) {
406 CurNodeH.getNode()->mergeTypeInfo(NH.getNode()->Ty, NOffset);
408 assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
410 // If we are merging a node with a completely folded node, then both nodes are
411 // now completely folded.
413 if (CurNodeH.getNode()->isNodeCompletelyFolded()) {
414 if (!NH.getNode()->isNodeCompletelyFolded()) {
415 NH.getNode()->foldNodeCompletely();
416 assert(NH.getOffset()==0 && "folding did not make offset 0?");
417 NOffset = NH.getOffset();
418 NSize = NH.getNode()->getSize();
419 assert(NOffset == 0 && NSize == 1);
421 } else if (NH.getNode()->isNodeCompletelyFolded()) {
422 CurNodeH.getNode()->foldNodeCompletely();
423 assert(CurNodeH.getOffset()==0 && "folding did not make offset 0?");
424 NOffset = NH.getOffset();
425 NSize = NH.getNode()->getSize();
426 assert(NOffset == 0 && NSize == 1);
429 if (CurNodeH.getNode() == NH.getNode() || NH.getNode() == 0) return;
430 assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
432 // Remove all edges pointing at N, causing them to point to 'this' instead.
433 // Make sure to adjust their offset, not just the node pointer.
434 // Also, be careful to use the DSNode* rather than NH since NH is one of
435 // the referrers and once NH refers to CurNodeH.getNode() this will
436 // become an infinite loop.
437 DSNode* N = NH.getNode();
438 unsigned OldNHOffset = NH.getOffset();
439 while (!N->Referrers.empty()) {
440 DSNodeHandle &Ref = *N->Referrers.back();
441 Ref = DSNodeHandle(CurNodeH.getNode(), NOffset+Ref.getOffset());
443 NH = DSNodeHandle(N, OldNHOffset); // reset NH to point back to where it was
445 assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
447 // Make all of the outgoing links of *NH now be outgoing links of
448 // this. This can cause recursive merging!
450 for (unsigned i = 0; i < NH.getNode()->getSize(); i += DS::PointerSize) {
451 DSNodeHandle &Link = NH.getNode()->getLink(i);
452 if (Link.getNode()) {
453 // Compute the offset into the current node at which to
454 // merge this link. In the common case, this is a linear
455 // relation to the offset in the original node (with
456 // wrapping), but if the current node gets collapsed due to
457 // recursive merging, we must make sure to merge in all remaining
458 // links at offset zero.
459 unsigned MergeOffset = 0;
460 if (CurNodeH.getNode()->Size != 1)
461 MergeOffset = (i+NOffset) % CurNodeH.getNode()->getSize();
462 CurNodeH.getNode()->addEdgeTo(MergeOffset, Link);
466 // Now that there are no outgoing edges, all of the Links are dead.
467 NH.getNode()->Links.clear();
468 NH.getNode()->Size = 0;
469 NH.getNode()->Ty = Type::VoidTy;
471 // Merge the node types
472 CurNodeH.getNode()->NodeType |= NH.getNode()->NodeType;
473 NH.getNode()->NodeType = DEAD; // NH is now a dead node.
475 // Merge the globals list...
476 if (!NH.getNode()->Globals.empty()) {
477 MergeSortedVectors(CurNodeH.getNode()->Globals, NH.getNode()->Globals);
479 // Delete the globals from the old node...
480 NH.getNode()->Globals.clear();
485 // mergeWith - Merge this node and the specified node, moving all links to and
486 // from the argument node into the current node, deleting the node argument.
487 // Offset indicates what offset the specified node is to be merged into the
490 // The specified node may be a null pointer (in which case, nothing happens).
492 void DSNode::mergeWith(const DSNodeHandle &NH, unsigned Offset) {
493 DSNode *N = NH.getNode();
494 if (N == 0 || (N == this && NH.getOffset() == Offset))
497 assert((N->NodeType & DSNode::DEAD) == 0);
498 assert((NodeType & DSNode::DEAD) == 0);
499 assert(!hasNoReferrers() && "Should not try to fold a useless node!");
502 // We cannot merge two pieces of the same node together, collapse the node
504 DEBUG(std::cerr << "Attempting to merge two chunks of"
505 << " the same node together!\n");
506 foldNodeCompletely();
510 // If both nodes are not at offset 0, make sure that we are merging the node
511 // at an later offset into the node with the zero offset.
513 if (Offset < NH.getOffset()) {
514 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
516 } else if (Offset == NH.getOffset() && getSize() < N->getSize()) {
517 // If the offsets are the same, merge the smaller node into the bigger node
518 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
522 // Ok, now we can merge the two nodes. Use a static helper that works with
523 // two node handles, since "this" may get merged away at intermediate steps.
524 DSNodeHandle CurNodeH(this, Offset);
525 DSNodeHandle NHCopy(NH);
526 DSNode::MergeNodes(CurNodeH, NHCopy);
529 //===----------------------------------------------------------------------===//
530 // DSCallSite Implementation
531 //===----------------------------------------------------------------------===//
533 // Define here to avoid including iOther.h and BasicBlock.h in DSGraph.h
534 Function &DSCallSite::getCaller() const {
535 return *Inst->getParent()->getParent();
539 //===----------------------------------------------------------------------===//
540 // DSGraph Implementation
541 //===----------------------------------------------------------------------===//
543 DSGraph::DSGraph(const DSGraph &G) : Func(G.Func), GlobalsGraph(0) {
544 PrintAuxCalls = false;
545 std::map<const DSNode*, DSNodeHandle> NodeMap;
546 RetNode = cloneInto(G, ScalarMap, NodeMap);
549 DSGraph::DSGraph(const DSGraph &G,
550 std::map<const DSNode*, DSNodeHandle> &NodeMap)
551 : Func(G.Func), GlobalsGraph(0) {
552 PrintAuxCalls = false;
553 RetNode = cloneInto(G, ScalarMap, NodeMap);
556 DSGraph::~DSGraph() {
557 FunctionCalls.clear();
558 AuxFunctionCalls.clear();
562 // Drop all intra-node references, so that assertions don't fail...
563 std::for_each(Nodes.begin(), Nodes.end(),
564 std::mem_fun(&DSNode::dropAllReferences));
566 // Delete all of the nodes themselves...
567 std::for_each(Nodes.begin(), Nodes.end(), deleter<DSNode>);
570 // dump - Allow inspection of graph in a debugger.
571 void DSGraph::dump() const { print(std::cerr); }
574 /// remapLinks - Change all of the Links in the current node according to the
575 /// specified mapping.
577 void DSNode::remapLinks(std::map<const DSNode*, DSNodeHandle> &OldNodeMap) {
578 for (unsigned i = 0, e = Links.size(); i != e; ++i) {
579 DSNodeHandle &H = OldNodeMap[Links[i].getNode()];
580 Links[i].setNode(H.getNode());
581 Links[i].setOffset(Links[i].getOffset()+H.getOffset());
586 // cloneInto - Clone the specified DSGraph into the current graph, returning the
587 // Return node of the graph. The translated ScalarMap for the old function is
588 // filled into the OldValMap member. If StripAllocas is set to true, Alloca
589 // markers are removed from the graph, as the graph is being cloned into a
590 // calling function's graph.
592 DSNodeHandle DSGraph::cloneInto(const DSGraph &G,
593 std::map<Value*, DSNodeHandle> &OldValMap,
594 std::map<const DSNode*, DSNodeHandle> &OldNodeMap,
595 unsigned CloneFlags) {
596 assert(OldNodeMap.empty() && "Returned OldNodeMap should be empty!");
597 assert(&G != this && "Cannot clone graph into itself!");
599 unsigned FN = Nodes.size(); // First new node...
601 // Duplicate all of the nodes, populating the node map...
602 Nodes.reserve(FN+G.Nodes.size());
603 for (unsigned i = 0, e = G.Nodes.size(); i != e; ++i) {
604 DSNode *Old = G.Nodes[i];
605 DSNode *New = new DSNode(*Old);
606 New->NodeType &= ~DSNode::DEAD; // Clear dead flag...
607 Nodes.push_back(New);
608 OldNodeMap[Old] = New;
612 Timer::addPeakMemoryMeasurement();
615 // Rewrite the links in the new nodes to point into the current graph now.
616 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
617 Nodes[i]->remapLinks(OldNodeMap);
619 // Remove alloca markers as specified
620 if (CloneFlags & (StripAllocaBit | StripModRefBits)) {
621 unsigned short clearBits = (CloneFlags & StripAllocaBit
622 ? DSNode::AllocaNode : 0)
623 | (CloneFlags & StripModRefBits
624 ? (DSNode::Modified | DSNode::Read) : 0);
625 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
626 Nodes[i]->NodeType &= ~clearBits;
629 // Copy the value map... and merge all of the global nodes...
630 for (std::map<Value*, DSNodeHandle>::const_iterator I = G.ScalarMap.begin(),
631 E = G.ScalarMap.end(); I != E; ++I) {
632 DSNodeHandle &H = OldValMap[I->first];
633 DSNodeHandle &MappedNode = OldNodeMap[I->second.getNode()];
634 H.setNode(MappedNode.getNode());
635 H.setOffset(I->second.getOffset()+MappedNode.getOffset());
637 if (isa<GlobalValue>(I->first)) { // Is this a global?
638 std::map<Value*, DSNodeHandle>::iterator GVI = ScalarMap.find(I->first);
639 if (GVI != ScalarMap.end()) { // Is the global value in this fn already?
640 GVI->second.mergeWith(H);
642 ScalarMap[I->first] = H; // Add global pointer to this graph
647 if (!(CloneFlags & DontCloneCallNodes)) {
648 // Copy the function calls list...
649 unsigned FC = FunctionCalls.size(); // FirstCall
650 FunctionCalls.reserve(FC+G.FunctionCalls.size());
651 for (unsigned i = 0, ei = G.FunctionCalls.size(); i != ei; ++i)
652 FunctionCalls.push_back(DSCallSite(G.FunctionCalls[i], OldNodeMap));
655 if (!(CloneFlags & DontCloneAuxCallNodes)) {
656 // Copy the auxillary function calls list...
657 unsigned FC = AuxFunctionCalls.size(); // FirstCall
658 AuxFunctionCalls.reserve(FC+G.AuxFunctionCalls.size());
659 for (unsigned i = 0, ei = G.AuxFunctionCalls.size(); i != ei; ++i)
660 AuxFunctionCalls.push_back(DSCallSite(G.AuxFunctionCalls[i], OldNodeMap));
663 // Return the returned node pointer...
664 DSNodeHandle &MappedRet = OldNodeMap[G.RetNode.getNode()];
665 return DSNodeHandle(MappedRet.getNode(),
666 MappedRet.getOffset()+G.RetNode.getOffset());
669 /// mergeInGraph - The method is used for merging graphs together. If the
670 /// argument graph is not *this, it makes a clone of the specified graph, then
671 /// merges the nodes specified in the call site with the formal arguments in the
674 void DSGraph::mergeInGraph(DSCallSite &CS, const DSGraph &Graph,
675 unsigned CloneFlags) {
676 std::map<Value*, DSNodeHandle> OldValMap;
678 std::map<Value*, DSNodeHandle> *ScalarMap = &OldValMap;
680 // If this is not a recursive call, clone the graph into this graph...
681 if (&Graph != this) {
682 // Clone the callee's graph into the current graph, keeping
683 // track of where scalars in the old graph _used_ to point,
684 // and of the new nodes matching nodes of the old graph.
685 std::map<const DSNode*, DSNodeHandle> OldNodeMap;
687 // The clone call may invalidate any of the vectors in the data
688 // structure graph. Strip locals and don't copy the list of callers
689 RetVal = cloneInto(Graph, OldValMap, OldNodeMap, CloneFlags);
690 ScalarMap = &OldValMap;
692 RetVal = getRetNode();
693 ScalarMap = &getScalarMap();
696 // Merge the return value with the return value of the context...
697 RetVal.mergeWith(CS.getRetVal());
699 // Resolve all of the function arguments...
700 Function &F = Graph.getFunction();
701 Function::aiterator AI = F.abegin();
703 for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i, ++AI) {
704 // Advance the argument iterator to the first pointer argument...
705 while (!isPointerType(AI->getType())) {
709 std::cerr << "Bad call to Function: " << F.getName() << "\n";
711 assert(AI != F.aend() && "# Args provided is not # Args required!");
714 // Add the link from the argument scalar to the provided value
715 DSNodeHandle &NH = (*ScalarMap)[AI];
716 assert(NH.getNode() && "Pointer argument without scalarmap entry?");
717 NH.mergeWith(CS.getPtrArg(i));
722 // cloneGlobalInto - Clone the given global node and all its target links
723 // (and all their llinks, recursively).
725 DSNode *DSGraph::cloneGlobalInto(const DSNode *GNode) {
726 if (GNode == 0 || GNode->getGlobals().size() == 0) return 0;
728 // If a clone has already been created for GNode, return it.
729 DSNodeHandle& ValMapEntry = ScalarMap[GNode->getGlobals()[0]];
730 if (ValMapEntry != 0)
733 // Clone the node and update the ValMap.
734 DSNode* NewNode = new DSNode(*GNode);
735 ValMapEntry = NewNode; // j=0 case of loop below!
736 Nodes.push_back(NewNode);
737 for (unsigned j = 1, N = NewNode->getGlobals().size(); j < N; ++j)
738 ScalarMap[NewNode->getGlobals()[j]] = NewNode;
740 // Rewrite the links in the new node to point into the current graph.
741 for (unsigned j = 0, e = GNode->getNumLinks(); j != e; ++j)
742 NewNode->setLink(j, cloneGlobalInto(GNode->getLink(j)));
749 // markIncompleteNodes - Mark the specified node as having contents that are not
750 // known with the current analysis we have performed. Because a node makes all
751 // of the nodes it can reach imcomplete if the node itself is incomplete, we
752 // must recursively traverse the data structure graph, marking all reachable
753 // nodes as incomplete.
755 static void markIncompleteNode(DSNode *N) {
756 // Stop recursion if no node, or if node already marked...
757 if (N == 0 || (N->NodeType & DSNode::Incomplete)) return;
759 // Actually mark the node
760 N->NodeType |= DSNode::Incomplete;
762 // Recusively process children...
763 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
764 if (DSNode *DSN = N->getLink(i).getNode())
765 markIncompleteNode(DSN);
768 static void markIncomplete(DSCallSite &Call) {
769 // Then the return value is certainly incomplete!
770 markIncompleteNode(Call.getRetVal().getNode());
772 // All objects pointed to by function arguments are incomplete!
773 for (unsigned i = 0, e = Call.getNumPtrArgs(); i != e; ++i)
774 markIncompleteNode(Call.getPtrArg(i).getNode());
777 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
778 // modified by other functions that have not been resolved yet. This marks
779 // nodes that are reachable through three sources of "unknownness":
781 // Global Variables, Function Calls, and Incoming Arguments
783 // For any node that may have unknown components (because something outside the
784 // scope of current analysis may have modified it), the 'Incomplete' flag is
785 // added to the NodeType.
787 void DSGraph::markIncompleteNodes(unsigned Flags) {
788 // Mark any incoming arguments as incomplete...
789 if ((Flags & DSGraph::MarkFormalArgs) && Func)
790 for (Function::aiterator I = Func->abegin(), E = Func->aend(); I != E; ++I)
791 if (isPointerType(I->getType()) && ScalarMap.find(I) != ScalarMap.end())
792 markIncompleteNode(ScalarMap[I].getNode());
794 // Mark stuff passed into functions calls as being incomplete...
795 if (!shouldPrintAuxCalls())
796 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
797 markIncomplete(FunctionCalls[i]);
799 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
800 markIncomplete(AuxFunctionCalls[i]);
803 // Mark all of the nodes pointed to by global nodes as incomplete...
804 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
805 if (Nodes[i]->NodeType & DSNode::GlobalNode) {
806 DSNode *N = Nodes[i];
807 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
808 if (DSNode *DSN = N->getLink(i).getNode())
809 markIncompleteNode(DSN);
813 // removeRefsToGlobal - Helper function that removes globals from the
814 // ScalarMap so that the referrer count will go down to zero.
815 static void removeRefsToGlobal(DSNode* N,
816 std::map<Value*, DSNodeHandle> &ScalarMap) {
817 while (!N->getGlobals().empty()) {
818 GlobalValue *GV = N->getGlobals().back();
819 N->getGlobals().pop_back();
825 // isNodeDead - This method checks to see if a node is dead, and if it isn't, it
826 // checks to see if there are simple transformations that it can do to make it
829 bool DSGraph::isNodeDead(DSNode *N) {
830 // Is it a trivially dead shadow node?
831 return N->getReferrers().empty() && (N->NodeType & ~DSNode::DEAD) == 0;
834 static inline void killIfUselessEdge(DSNodeHandle &Edge) {
835 if (DSNode *N = Edge.getNode()) // Is there an edge?
836 if (N->getReferrers().size() == 1) // Does it point to a lonely node?
837 if ((N->NodeType & ~DSNode::Incomplete) == 0 && // No interesting info?
838 N->getType() == Type::VoidTy && !N->isNodeCompletelyFolded())
839 Edge.setNode(0); // Kill the edge!
842 static inline bool nodeContainsExternalFunction(const DSNode *N) {
843 const std::vector<GlobalValue*> &Globals = N->getGlobals();
844 for (unsigned i = 0, e = Globals.size(); i != e; ++i)
845 if (Globals[i]->isExternal())
850 static void removeIdenticalCalls(vector<DSCallSite> &Calls,
851 const std::string &where) {
852 // Remove trivially identical function calls
853 unsigned NumFns = Calls.size();
854 std::sort(Calls.begin(), Calls.end()); // Sort by callee as primary key!
856 // Scan the call list cleaning it up as necessary...
857 DSNode *LastCalleeNode = 0;
858 unsigned NumDuplicateCalls = 0;
859 bool LastCalleeContainsExternalFunction = false;
860 for (unsigned i = 0; i != Calls.size(); ++i) {
861 DSCallSite &CS = Calls[i];
863 // If the Callee is a useless edge, this must be an unreachable call site,
865 killIfUselessEdge(CS.getCallee());
866 if (CS.getCallee().getNode() == 0) {
867 CS.swap(Calls.back());
871 // If the return value or any arguments point to a void node with no
872 // information at all in it, and the call node is the only node to point
873 // to it, remove the edge to the node (killing the node).
875 killIfUselessEdge(CS.getRetVal());
876 for (unsigned a = 0, e = CS.getNumPtrArgs(); a != e; ++a)
877 killIfUselessEdge(CS.getPtrArg(a));
879 // If this call site calls the same function as the last call site, and if
880 // the function pointer contains an external function, this node will
881 // never be resolved. Merge the arguments of the call node because no
882 // information will be lost.
884 if (CS.getCallee().getNode() == LastCalleeNode) {
886 if (NumDuplicateCalls == 1) {
887 LastCalleeContainsExternalFunction =
888 nodeContainsExternalFunction(LastCalleeNode);
891 if (LastCalleeContainsExternalFunction ||
892 // This should be more than enough context sensitivity!
893 // FIXME: Evaluate how many times this is tripped!
894 NumDuplicateCalls > 20) {
895 DSCallSite &OCS = Calls[i-1];
898 // The node will now be eliminated as a duplicate!
899 if (CS.getNumPtrArgs() < OCS.getNumPtrArgs())
901 else if (CS.getNumPtrArgs() > OCS.getNumPtrArgs())
905 LastCalleeNode = CS.getCallee().getNode();
906 NumDuplicateCalls = 0;
911 Calls.erase(std::unique(Calls.begin(), Calls.end()),
914 // Track the number of call nodes merged away...
915 NumCallNodesMerged += NumFns-Calls.size();
917 DEBUG(if (NumFns != Calls.size())
918 std::cerr << "Merged " << (NumFns-Calls.size())
919 << " call nodes in " << where << "\n";);
923 // removeTriviallyDeadNodes - After the graph has been constructed, this method
924 // removes all unreachable nodes that are created because they got merged with
925 // other nodes in the graph. These nodes will all be trivially unreachable, so
926 // we don't have to perform any non-trivial analysis here.
928 void DSGraph::removeTriviallyDeadNodes() {
929 removeIdenticalCalls(FunctionCalls, Func ? Func->getName() : "");
930 removeIdenticalCalls(AuxFunctionCalls, Func ? Func->getName() : "");
932 for (unsigned i = 0; i != Nodes.size(); ++i)
933 if (isNodeDead(Nodes[i])) { // This node is dead!
934 delete Nodes[i]; // Free memory...
935 Nodes.erase(Nodes.begin()+i--); // Remove from node list...
940 /// markReachableNodes - This method recursively traverses the specified
941 /// DSNodes, marking any nodes which are reachable. All reachable nodes it adds
942 /// to the set, which allows it to only traverse visited nodes once.
944 void DSNode::markReachableNodes(std::set<DSNode*> &ReachableNodes) {
945 if (this == 0) return;
946 std::set<DSNode*>::iterator I = ReachableNodes.lower_bound(this);
947 if (I != ReachableNodes.end() && *I == this)
948 return; // Already marked reachable
949 ReachableNodes.insert(I, this); // Is reachable now
951 for (unsigned i = 0, e = getSize(); i < e; i += DS::PointerSize)
952 getLink(i).getNode()->markReachableNodes(ReachableNodes);
955 void DSCallSite::markReachableNodes(std::set<DSNode*> &Nodes) {
956 getRetVal().getNode()->markReachableNodes(Nodes);
957 getCallee().getNode()->markReachableNodes(Nodes);
959 for (unsigned j = 0, e = getNumPtrArgs(); j != e; ++j)
960 getPtrArg(j).getNode()->markReachableNodes(Nodes);
963 // markAliveIfCanReachAlive - Simple graph walker that recursively traverses the
964 // graph looking for a node that is marked alive. If the node is marked alive,
965 // the recursive unwind marks node alive that can point to the alive node. This
966 // is basically just a post-order traversal.
968 // This function returns true if the specified node is alive.
970 static bool markAliveIfCanReachAlive(DSNode *N, std::set<DSNode*> &Alive,
971 std::set<DSNode*> &Visited) {
972 if (N == 0) return false;
974 // If we know that this node is alive, return so!
975 if (Alive.count(N)) return true;
977 // Otherwise, we don't think the node is alive yet, check for infinite
979 std::set<DSNode*>::iterator VI = Visited.lower_bound(N);
980 if (VI != Visited.end() && *VI == N) return false; // Found a cycle
981 // No recursion, insert into Visited...
982 Visited.insert(VI, N);
984 if (N->NodeType & DSNode::GlobalNode)
985 return false; // Global nodes will be marked on their own
987 bool ChildrenAreAlive = false;
989 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
990 ChildrenAreAlive |= markAliveIfCanReachAlive(N->getLink(i).getNode(),
992 if (ChildrenAreAlive)
993 N->markReachableNodes(Alive);
994 return ChildrenAreAlive;
997 static bool CallSiteUsesAliveArgs(DSCallSite &CS, std::set<DSNode*> &Alive,
998 std::set<DSNode*> &Visited) {
999 if (markAliveIfCanReachAlive(CS.getRetVal().getNode(), Alive, Visited) ||
1000 markAliveIfCanReachAlive(CS.getCallee().getNode(), Alive, Visited))
1002 for (unsigned j = 0, e = CS.getNumPtrArgs(); j != e; ++j)
1003 if (markAliveIfCanReachAlive(CS.getPtrArg(j).getNode(), Alive, Visited))
1008 // GlobalIsAlivenessRoot - Return true if the specified global node is
1009 // intrinsically alive in the context of the current graph (ie, it is a root of
1010 // aliveness). For TD graphs, no globals are. For the BU graphs all are unless
1011 // they are trivial globals...
1013 static bool GlobalIsAlivenessRoot(DSNode *N, unsigned Flags) {
1014 if (Flags & DSGraph::RemoveUnreachableGlobals)
1015 return false; // If we are to remove all globals, go for it.
1017 // Ok, we are keeping globals... hrm, we can still delete it if it has no
1018 // links, and no mod/ref or other info... If it is not modified, it can't
1021 if ((N->NodeType & ~(DSNode::Composition | DSNode::Array)) == 0)
1026 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
1027 // subgraphs that are unreachable. This often occurs because the data
1028 // structure doesn't "escape" into it's caller, and thus should be eliminated
1029 // from the caller's graph entirely. This is only appropriate to use when
1032 void DSGraph::removeDeadNodes(unsigned Flags) {
1033 // Reduce the amount of work we have to do...
1034 removeTriviallyDeadNodes();
1036 // FIXME: Merge nontrivially identical call nodes...
1038 // Alive - a set that holds all nodes found to be reachable/alive.
1039 std::set<DSNode*> Alive;
1040 std::vector<std::pair<Value*, DSNode*> > GlobalNodes;
1042 // Mark all nodes reachable by (non-global) scalar nodes as alive...
1043 for (std::map<Value*, DSNodeHandle>::iterator I = ScalarMap.begin(),
1044 E = ScalarMap.end(); I != E; ++I)
1045 if (!isa<GlobalValue>(I->first) ||
1046 GlobalIsAlivenessRoot(I->second.getNode(), Flags))
1047 I->second.getNode()->markReachableNodes(Alive);
1048 else // Keep track of global nodes
1049 GlobalNodes.push_back(std::make_pair(I->first, I->second.getNode()));
1051 // The return value is alive as well...
1052 RetNode.getNode()->markReachableNodes(Alive);
1054 // If any global nodes points to a non-global that is "alive", the global is
1055 // "alive" as well...
1057 std::set<DSNode*> Visited;
1058 for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
1059 markAliveIfCanReachAlive(GlobalNodes[i].second, Alive, Visited);
1061 std::vector<bool> FCallsAlive(FunctionCalls.size());
1062 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
1063 if (!(Flags & DSGraph::RemoveUnreachableGlobals) ||
1064 CallSiteUsesAliveArgs(FunctionCalls[i], Alive, Visited)) {
1065 FunctionCalls[i].markReachableNodes(Alive);
1066 FCallsAlive[i] = true;
1069 std::vector<bool> AuxFCallsAlive(AuxFunctionCalls.size());
1070 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
1071 if (CallSiteUsesAliveArgs(AuxFunctionCalls[i], Alive, Visited)) {
1072 AuxFunctionCalls[i].markReachableNodes(Alive);
1073 AuxFCallsAlive[i] = true;
1076 // Remove all dead function calls...
1077 unsigned CurIdx = 0;
1078 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
1080 FunctionCalls[CurIdx++].swap(FunctionCalls[i]);
1081 // Crop all the bad ones out...
1082 FunctionCalls.erase(FunctionCalls.begin()+CurIdx, FunctionCalls.end());
1084 // Remove all dead aux function calls...
1086 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
1087 if (AuxFCallsAlive[i])
1088 AuxFunctionCalls[CurIdx++].swap(AuxFunctionCalls[i]);
1089 // Crop all the bad ones out...
1090 AuxFunctionCalls.erase(AuxFunctionCalls.begin()+CurIdx,
1091 AuxFunctionCalls.end());
1094 // Remove all unreachable globals from the ScalarMap
1095 for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
1096 if (!Alive.count(GlobalNodes[i].second))
1097 ScalarMap.erase(GlobalNodes[i].first);
1099 // Loop over all unreachable nodes, dropping their references...
1100 vector<DSNode*> DeadNodes;
1101 DeadNodes.reserve(Nodes.size()); // Only one allocation is allowed.
1102 for (unsigned i = 0; i != Nodes.size(); ++i)
1103 if (!Alive.count(Nodes[i])) {
1104 DSNode *N = Nodes[i];
1105 Nodes.erase(Nodes.begin()+i--); // Erase node from alive list.
1106 DeadNodes.push_back(N); // Add node to our list of dead nodes
1107 N->dropAllReferences(); // Drop all outgoing edges
1110 // Delete all dead nodes...
1111 std::for_each(DeadNodes.begin(), DeadNodes.end(), deleter<DSNode>);
1115 //===----------------------------------------------------------------------===//
1116 // GlobalDSGraph Implementation
1117 //===----------------------------------------------------------------------===//
1120 // Bits used in the next function
1121 static const char ExternalTypeBits = DSNode::GlobalNode | DSNode::HeapNode;
1124 // GlobalDSGraph::cloneNodeInto - Clone a global node and all its externally
1125 // visible target links (and recursively their such links) into this graph.
1126 // NodeCache maps the node being cloned to its clone in the Globals graph,
1127 // in order to track cycles.
1128 // GlobalsAreFinal is a flag that says whether it is safe to assume that
1129 // an existing global node is complete. This is important to avoid
1130 // reinserting all globals when inserting Calls to functions.
1131 // This is a helper function for cloneGlobals and cloneCalls.
1133 DSNode* GlobalDSGraph::cloneNodeInto(DSNode *OldNode,
1134 std::map<const DSNode*, DSNode*> &NodeCache,
1135 bool GlobalsAreFinal) {
1136 if (OldNode == 0) return 0;
1138 // The caller should check this is an external node. Just more efficient...
1139 assert((OldNode->NodeType & ExternalTypeBits) && "Non-external node");
1141 // If a clone has already been created for OldNode, return it.
1142 DSNode*& CacheEntry = NodeCache[OldNode];
1143 if (CacheEntry != 0)
1146 // The result value...
1147 DSNode* NewNode = 0;
1149 // If nodes already exist for any of the globals of OldNode,
1150 // merge all such nodes together since they are merged in OldNode.
1151 // If ValueCacheIsFinal==true, look for an existing node that has
1152 // an identical list of globals and return it if it exists.
1154 for (unsigned j = 0, N = OldNode->getGlobals().size(); j != N; ++j)
1155 if (DSNode *PrevNode = ScalarMap[OldNode->getGlobals()[j]].getNode()) {
1157 NewNode = PrevNode; // first existing node found
1158 if (GlobalsAreFinal && j == 0)
1159 if (OldNode->getGlobals() == PrevNode->getGlobals()) {
1160 CacheEntry = NewNode;
1164 else if (NewNode != PrevNode) { // found another, different from prev
1165 // update ValMap *before* merging PrevNode into NewNode
1166 for (unsigned k = 0, NK = PrevNode->getGlobals().size(); k < NK; ++k)
1167 ScalarMap[PrevNode->getGlobals()[k]] = NewNode;
1168 NewNode->mergeWith(PrevNode);
1170 } else if (NewNode != 0) {
1171 ScalarMap[OldNode->getGlobals()[j]] = NewNode; // add the merged node
1174 // If no existing node was found, clone the node and update the ValMap.
1176 NewNode = new DSNode(*OldNode);
1177 Nodes.push_back(NewNode);
1178 for (unsigned j = 0, e = NewNode->getNumLinks(); j != e; ++j)
1179 NewNode->setLink(j, 0);
1180 for (unsigned j = 0, N = NewNode->getGlobals().size(); j < N; ++j)
1181 ScalarMap[NewNode->getGlobals()[j]] = NewNode;
1184 NewNode->NodeType |= OldNode->NodeType; // Markers may be different!
1186 // Add the entry to NodeCache
1187 CacheEntry = NewNode;
1189 // Rewrite the links in the new node to point into the current graph,
1190 // but only for links to external nodes. Set other links to NULL.
1191 for (unsigned j = 0, e = OldNode->getNumLinks(); j != e; ++j) {
1192 DSNode* OldTarget = OldNode->getLink(j);
1193 if (OldTarget && (OldTarget->NodeType & ExternalTypeBits)) {
1194 DSNode* NewLink = this->cloneNodeInto(OldTarget, NodeCache);
1195 if (NewNode->getLink(j))
1196 NewNode->getLink(j)->mergeWith(NewLink);
1198 NewNode->setLink(j, NewLink);
1202 // Remove all local markers
1203 NewNode->NodeType &= ~(DSNode::AllocaNode | DSNode::ScalarNode);
1209 // GlobalDSGraph::cloneCalls - Clone function calls and their visible target
1210 // links (and recursively their such links) into this graph.
1212 void GlobalDSGraph::cloneCalls(DSGraph& Graph) {
1213 std::map<const DSNode*, DSNode*> NodeCache;
1214 vector<DSCallSite >& FromCalls =Graph.FunctionCalls;
1216 FunctionCalls.reserve(FunctionCalls.size() + FromCalls.size());
1218 for (int i = 0, ei = FromCalls.size(); i < ei; ++i) {
1219 DSCallSite& callCopy = FunctionCalls.back();
1220 callCopy.reserve(FromCalls[i].size());
1221 for (unsigned j = 0, ej = FromCalls[i].size(); j != ej; ++j)
1223 ((FromCalls[i][j] && (FromCalls[i][j]->NodeType & ExternalTypeBits))
1224 ? cloneNodeInto(FromCalls[i][j], NodeCache, true)
1228 // remove trivially identical function calls
1229 removeIdenticalCalls(FunctionCalls, "Globals Graph");