1 //===- DataStructure.cpp - Implement the core data structure analysis -----===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the core data structure functionality.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Analysis/DataStructure/DSGraphTraits.h"
15 #include "llvm/Constants.h"
16 #include "llvm/Function.h"
17 #include "llvm/GlobalVariable.h"
18 #include "llvm/Instructions.h"
19 #include "llvm/DerivedTypes.h"
20 #include "llvm/Target/TargetData.h"
21 #include "llvm/Assembly/Writer.h"
22 #include "llvm/Support/CommandLine.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/ADT/DepthFirstIterator.h"
25 #include "llvm/ADT/STLExtras.h"
26 #include "llvm/ADT/SCCIterator.h"
27 #include "llvm/ADT/Statistic.h"
28 #include "llvm/Support/Timer.h"
32 #define COLLAPSE_ARRAYS_AGGRESSIVELY 0
35 Statistic<> NumFolds ("dsa", "Number of nodes completely folded");
36 Statistic<> NumCallNodesMerged("dsa", "Number of call nodes merged");
37 Statistic<> NumNodeAllocated ("dsa", "Number of nodes allocated");
38 Statistic<> NumDNE ("dsa", "Number of nodes removed by reachability");
39 Statistic<> NumTrivialDNE ("dsa", "Number of nodes trivially removed");
40 Statistic<> NumTrivialGlobalDNE("dsa", "Number of globals trivially removed");
44 #define TIME_REGION(VARNAME, DESC) \
45 NamedRegionTimer VARNAME(DESC)
47 #define TIME_REGION(VARNAME, DESC)
52 /// isForwarding - Return true if this NodeHandle is forwarding to another
54 bool DSNodeHandle::isForwarding() const {
55 return N && N->isForwarding();
58 DSNode *DSNodeHandle::HandleForwarding() const {
59 assert(N->isForwarding() && "Can only be invoked if forwarding!");
61 // Handle node forwarding here!
62 DSNode *Next = N->ForwardNH.getNode(); // Cause recursive shrinkage
63 Offset += N->ForwardNH.getOffset();
65 if (--N->NumReferrers == 0) {
66 // Removing the last referrer to the node, sever the forwarding link
72 if (N->Size <= Offset) {
73 assert(N->Size <= 1 && "Forwarded to shrunk but not collapsed node?");
79 //===----------------------------------------------------------------------===//
80 // DSScalarMap Implementation
81 //===----------------------------------------------------------------------===//
83 DSNodeHandle &DSScalarMap::AddGlobal(GlobalValue *GV) {
84 assert(ValueMap.count(GV) == 0 && "GV already exists!");
86 // If the node doesn't exist, check to see if it's a global that is
87 // equated to another global in the program.
88 EquivalenceClasses<GlobalValue*>::iterator ECI = GlobalECs.findValue(GV);
89 if (ECI != GlobalECs.end()) {
90 GlobalValue *Leader = *GlobalECs.findLeader(ECI);
93 iterator I = ValueMap.find(GV);
94 if (I != ValueMap.end())
99 // Okay, this is either not an equivalenced global or it is the leader, it
100 // will be inserted into the scalar map now.
101 GlobalSet.insert(GV);
103 return ValueMap.insert(std::make_pair(GV, DSNodeHandle())).first->second;
107 //===----------------------------------------------------------------------===//
108 // DSNode Implementation
109 //===----------------------------------------------------------------------===//
111 DSNode::DSNode(const Type *T, DSGraph *G)
112 : NumReferrers(0), Size(0), ParentGraph(G), Ty(Type::VoidTy), NodeType(0) {
113 // Add the type entry if it is specified...
114 if (T) mergeTypeInfo(T, 0);
115 if (G) G->addNode(this);
119 // DSNode copy constructor... do not copy over the referrers list!
120 DSNode::DSNode(const DSNode &N, DSGraph *G, bool NullLinks)
121 : NumReferrers(0), Size(N.Size), ParentGraph(G),
122 Ty(N.Ty), Globals(N.Globals), NodeType(N.NodeType) {
126 Links.resize(N.Links.size()); // Create the appropriate number of null links
131 /// getTargetData - Get the target data object used to construct this node.
133 const TargetData &DSNode::getTargetData() const {
134 return ParentGraph->getTargetData();
137 void DSNode::assertOK() const {
138 assert((Ty != Type::VoidTy ||
139 Ty == Type::VoidTy && (Size == 0 ||
140 (NodeType & DSNode::Array))) &&
143 assert(ParentGraph && "Node has no parent?");
144 const DSScalarMap &SM = ParentGraph->getScalarMap();
145 for (unsigned i = 0, e = Globals.size(); i != e; ++i) {
146 assert(SM.global_count(Globals[i]));
147 assert(SM.find(Globals[i])->second.getNode() == this);
151 /// forwardNode - Mark this node as being obsolete, and all references to it
152 /// should be forwarded to the specified node and offset.
154 void DSNode::forwardNode(DSNode *To, unsigned Offset) {
155 assert(this != To && "Cannot forward a node to itself!");
156 assert(ForwardNH.isNull() && "Already forwarding from this node!");
157 if (To->Size <= 1) Offset = 0;
158 assert((Offset < To->Size || (Offset == To->Size && Offset == 0)) &&
159 "Forwarded offset is wrong!");
160 ForwardNH.setTo(To, Offset);
165 // Remove this node from the parent graph's Nodes list.
166 ParentGraph->unlinkNode(this);
170 // addGlobal - Add an entry for a global value to the Globals list. This also
171 // marks the node with the 'G' flag if it does not already have it.
173 void DSNode::addGlobal(GlobalValue *GV) {
174 // First, check to make sure this is the leader if the global is in an
175 // equivalence class.
176 GV = getParentGraph()->getScalarMap().getLeaderForGlobal(GV);
178 // Keep the list sorted.
179 std::vector<GlobalValue*>::iterator I =
180 std::lower_bound(Globals.begin(), Globals.end(), GV);
182 if (I == Globals.end() || *I != GV) {
183 Globals.insert(I, GV);
184 NodeType |= GlobalNode;
188 // removeGlobal - Remove the specified global that is explicitly in the globals
190 void DSNode::removeGlobal(GlobalValue *GV) {
191 std::vector<GlobalValue*>::iterator I =
192 std::lower_bound(Globals.begin(), Globals.end(), GV);
193 assert(I != Globals.end() && *I == GV && "Global not in node!");
197 /// foldNodeCompletely - If we determine that this node has some funny
198 /// behavior happening to it that we cannot represent, we fold it down to a
199 /// single, completely pessimistic, node. This node is represented as a
200 /// single byte with a single TypeEntry of "void".
202 void DSNode::foldNodeCompletely() {
203 if (isNodeCompletelyFolded()) return; // If this node is already folded...
207 // If this node has a size that is <= 1, we don't need to create a forwarding
209 if (getSize() <= 1) {
210 NodeType |= DSNode::Array;
213 assert(Links.size() <= 1 && "Size is 1, but has more links?");
216 // Create the node we are going to forward to. This is required because
217 // some referrers may have an offset that is > 0. By forcing them to
218 // forward, the forwarder has the opportunity to correct the offset.
219 DSNode *DestNode = new DSNode(0, ParentGraph);
220 DestNode->NodeType = NodeType|DSNode::Array;
221 DestNode->Ty = Type::VoidTy;
223 DestNode->Globals.swap(Globals);
225 // Start forwarding to the destination node...
226 forwardNode(DestNode, 0);
228 if (!Links.empty()) {
229 DestNode->Links.reserve(1);
231 DSNodeHandle NH(DestNode);
232 DestNode->Links.push_back(Links[0]);
234 // If we have links, merge all of our outgoing links together...
235 for (unsigned i = Links.size()-1; i != 0; --i)
236 NH.getNode()->Links[0].mergeWith(Links[i]);
239 DestNode->Links.resize(1);
244 /// isNodeCompletelyFolded - Return true if this node has been completely
245 /// folded down to something that can never be expanded, effectively losing
246 /// all of the field sensitivity that may be present in the node.
248 bool DSNode::isNodeCompletelyFolded() const {
249 return getSize() == 1 && Ty == Type::VoidTy && isArray();
252 /// addFullGlobalsList - Compute the full set of global values that are
253 /// represented by this node. Unlike getGlobalsList(), this requires fair
254 /// amount of work to compute, so don't treat this method call as free.
255 void DSNode::addFullGlobalsList(std::vector<GlobalValue*> &List) const {
256 if (globals_begin() == globals_end()) return;
258 EquivalenceClasses<GlobalValue*> &EC = getParentGraph()->getGlobalECs();
260 for (globals_iterator I = globals_begin(), E = globals_end(); I != E; ++I) {
261 EquivalenceClasses<GlobalValue*>::iterator ECI = EC.findValue(*I);
265 List.insert(List.end(), EC.member_begin(ECI), EC.member_end());
269 /// addFullFunctionList - Identical to addFullGlobalsList, but only return the
270 /// functions in the full list.
271 void DSNode::addFullFunctionList(std::vector<Function*> &List) const {
272 if (globals_begin() == globals_end()) return;
274 EquivalenceClasses<GlobalValue*> &EC = getParentGraph()->getGlobalECs();
276 for (globals_iterator I = globals_begin(), E = globals_end(); I != E; ++I) {
277 EquivalenceClasses<GlobalValue*>::iterator ECI = EC.findValue(*I);
278 if (ECI == EC.end()) {
279 if (Function *F = dyn_cast<Function>(*I))
282 for (EquivalenceClasses<GlobalValue*>::member_iterator MI =
283 EC.member_begin(ECI), E = EC.member_end(); MI != E; ++MI)
284 if (Function *F = dyn_cast<Function>(*MI))
291 /// TypeElementWalker Class - Used for implementation of physical subtyping...
293 class TypeElementWalker {
298 StackState(const Type *T, unsigned Off = 0)
299 : Ty(T), Offset(Off), Idx(0) {}
302 std::vector<StackState> Stack;
303 const TargetData &TD;
305 TypeElementWalker(const Type *T, const TargetData &td) : TD(td) {
310 bool isDone() const { return Stack.empty(); }
311 const Type *getCurrentType() const { return Stack.back().Ty; }
312 unsigned getCurrentOffset() const { return Stack.back().Offset; }
314 void StepToNextType() {
315 PopStackAndAdvance();
320 /// PopStackAndAdvance - Pop the current element off of the stack and
321 /// advance the underlying element to the next contained member.
322 void PopStackAndAdvance() {
323 assert(!Stack.empty() && "Cannot pop an empty stack!");
325 while (!Stack.empty()) {
326 StackState &SS = Stack.back();
327 if (const StructType *ST = dyn_cast<StructType>(SS.Ty)) {
329 if (SS.Idx != ST->getNumElements()) {
330 const StructLayout *SL = TD.getStructLayout(ST);
332 unsigned(SL->MemberOffsets[SS.Idx]-SL->MemberOffsets[SS.Idx-1]);
335 Stack.pop_back(); // At the end of the structure
337 const ArrayType *AT = cast<ArrayType>(SS.Ty);
339 if (SS.Idx != AT->getNumElements()) {
340 SS.Offset += unsigned(TD.getTypeSize(AT->getElementType()));
343 Stack.pop_back(); // At the end of the array
348 /// StepToLeaf - Used by physical subtyping to move to the first leaf node
349 /// on the type stack.
351 if (Stack.empty()) return;
352 while (!Stack.empty() && !Stack.back().Ty->isFirstClassType()) {
353 StackState &SS = Stack.back();
354 if (const StructType *ST = dyn_cast<StructType>(SS.Ty)) {
355 if (ST->getNumElements() == 0) {
357 PopStackAndAdvance();
359 // Step into the structure...
360 assert(SS.Idx < ST->getNumElements());
361 const StructLayout *SL = TD.getStructLayout(ST);
362 Stack.push_back(StackState(ST->getElementType(SS.Idx),
363 SS.Offset+unsigned(SL->MemberOffsets[SS.Idx])));
366 const ArrayType *AT = cast<ArrayType>(SS.Ty);
367 if (AT->getNumElements() == 0) {
369 PopStackAndAdvance();
371 // Step into the array...
372 assert(SS.Idx < AT->getNumElements());
373 Stack.push_back(StackState(AT->getElementType(),
375 unsigned(TD.getTypeSize(AT->getElementType()))));
381 } // end anonymous namespace
383 /// ElementTypesAreCompatible - Check to see if the specified types are
384 /// "physically" compatible. If so, return true, else return false. We only
385 /// have to check the fields in T1: T2 may be larger than T1. If AllowLargerT1
386 /// is true, then we also allow a larger T1.
388 static bool ElementTypesAreCompatible(const Type *T1, const Type *T2,
389 bool AllowLargerT1, const TargetData &TD){
390 TypeElementWalker T1W(T1, TD), T2W(T2, TD);
392 while (!T1W.isDone() && !T2W.isDone()) {
393 if (T1W.getCurrentOffset() != T2W.getCurrentOffset())
396 const Type *T1 = T1W.getCurrentType();
397 const Type *T2 = T2W.getCurrentType();
398 if (T1 != T2 && !T1->isLosslesslyConvertibleTo(T2))
401 T1W.StepToNextType();
402 T2W.StepToNextType();
405 return AllowLargerT1 || T1W.isDone();
409 /// mergeTypeInfo - This method merges the specified type into the current node
410 /// at the specified offset. This may update the current node's type record if
411 /// this gives more information to the node, it may do nothing to the node if
412 /// this information is already known, or it may merge the node completely (and
413 /// return true) if the information is incompatible with what is already known.
415 /// This method returns true if the node is completely folded, otherwise false.
417 bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset,
418 bool FoldIfIncompatible) {
419 const TargetData &TD = getTargetData();
420 // Check to make sure the Size member is up-to-date. Size can be one of the
422 // Size = 0, Ty = Void: Nothing is known about this node.
423 // Size = 0, Ty = FnTy: FunctionPtr doesn't have a size, so we use zero
424 // Size = 1, Ty = Void, Array = 1: The node is collapsed
425 // Otherwise, sizeof(Ty) = Size
427 assert(((Size == 0 && Ty == Type::VoidTy && !isArray()) ||
428 (Size == 0 && !Ty->isSized() && !isArray()) ||
429 (Size == 1 && Ty == Type::VoidTy && isArray()) ||
430 (Size == 0 && !Ty->isSized() && !isArray()) ||
431 (TD.getTypeSize(Ty) == Size)) &&
432 "Size member of DSNode doesn't match the type structure!");
433 assert(NewTy != Type::VoidTy && "Cannot merge void type into DSNode!");
435 if (Offset == 0 && NewTy == Ty)
436 return false; // This should be a common case, handle it efficiently
438 // Return true immediately if the node is completely folded.
439 if (isNodeCompletelyFolded()) return true;
441 // If this is an array type, eliminate the outside arrays because they won't
442 // be used anyway. This greatly reduces the size of large static arrays used
443 // as global variables, for example.
445 bool WillBeArray = false;
446 while (const ArrayType *AT = dyn_cast<ArrayType>(NewTy)) {
447 // FIXME: we might want to keep small arrays, but must be careful about
448 // things like: [2 x [10000 x int*]]
449 NewTy = AT->getElementType();
453 // Figure out how big the new type we're merging in is...
454 unsigned NewTySize = NewTy->isSized() ? (unsigned)TD.getTypeSize(NewTy) : 0;
456 // Otherwise check to see if we can fold this type into the current node. If
457 // we can't, we fold the node completely, if we can, we potentially update our
460 if (Ty == Type::VoidTy) {
461 // If this is the first type that this node has seen, just accept it without
463 assert(Offset == 0 && !isArray() &&
464 "Cannot have an offset into a void node!");
466 // If this node would have to have an unreasonable number of fields, just
467 // collapse it. This can occur for fortran common blocks, which have stupid
468 // things like { [100000000 x double], [1000000 x double] }.
469 unsigned NumFields = (NewTySize+DS::PointerSize-1) >> DS::PointerShift;
470 if (NumFields > 256) {
471 foldNodeCompletely();
477 if (WillBeArray) NodeType |= Array;
480 // Calculate the number of outgoing links from this node.
481 Links.resize(NumFields);
485 // Handle node expansion case here...
486 if (Offset+NewTySize > Size) {
487 // It is illegal to grow this node if we have treated it as an array of
490 if (FoldIfIncompatible) foldNodeCompletely();
494 if (Offset) { // We could handle this case, but we don't for now...
495 std::cerr << "UNIMP: Trying to merge a growth type into "
496 << "offset != 0: Collapsing!\n";
497 if (FoldIfIncompatible) foldNodeCompletely();
501 // Okay, the situation is nice and simple, we are trying to merge a type in
502 // at offset 0 that is bigger than our current type. Implement this by
503 // switching to the new type and then merge in the smaller one, which should
504 // hit the other code path here. If the other code path decides it's not
505 // ok, it will collapse the node as appropriate.
508 // If this node would have to have an unreasonable number of fields, just
509 // collapse it. This can occur for fortran common blocks, which have stupid
510 // things like { [100000000 x double], [1000000 x double] }.
511 unsigned NumFields = (NewTySize+DS::PointerSize-1) >> DS::PointerShift;
512 if (NumFields > 256) {
513 foldNodeCompletely();
517 const Type *OldTy = Ty;
520 if (WillBeArray) NodeType |= Array;
523 // Must grow links to be the appropriate size...
524 Links.resize(NumFields);
526 // Merge in the old type now... which is guaranteed to be smaller than the
528 return mergeTypeInfo(OldTy, 0);
531 assert(Offset <= Size &&
532 "Cannot merge something into a part of our type that doesn't exist!");
534 // Find the section of Ty that NewTy overlaps with... first we find the
535 // type that starts at offset Offset.
538 const Type *SubType = Ty;
540 assert(Offset-O < TD.getTypeSize(SubType) && "Offset out of range!");
542 switch (SubType->getTypeID()) {
543 case Type::StructTyID: {
544 const StructType *STy = cast<StructType>(SubType);
545 const StructLayout &SL = *TD.getStructLayout(STy);
546 unsigned i = SL.getElementContainingOffset(Offset-O);
548 // The offset we are looking for must be in the i'th element...
549 SubType = STy->getElementType(i);
550 O += (unsigned)SL.MemberOffsets[i];
553 case Type::ArrayTyID: {
554 SubType = cast<ArrayType>(SubType)->getElementType();
555 unsigned ElSize = (unsigned)TD.getTypeSize(SubType);
556 unsigned Remainder = (Offset-O) % ElSize;
557 O = Offset-Remainder;
561 if (FoldIfIncompatible) foldNodeCompletely();
566 assert(O == Offset && "Could not achieve the correct offset!");
568 // If we found our type exactly, early exit
569 if (SubType == NewTy) return false;
571 // Differing function types don't require us to merge. They are not values
573 if (isa<FunctionType>(SubType) &&
574 isa<FunctionType>(NewTy)) return false;
576 unsigned SubTypeSize = SubType->isSized() ?
577 (unsigned)TD.getTypeSize(SubType) : 0;
579 // Ok, we are getting desperate now. Check for physical subtyping, where we
580 // just require each element in the node to be compatible.
581 if (NewTySize <= SubTypeSize && NewTySize && NewTySize < 256 &&
582 SubTypeSize && SubTypeSize < 256 &&
583 ElementTypesAreCompatible(NewTy, SubType, !isArray(), TD))
586 // Okay, so we found the leader type at the offset requested. Search the list
587 // of types that starts at this offset. If SubType is currently an array or
588 // structure, the type desired may actually be the first element of the
591 unsigned PadSize = SubTypeSize; // Size, including pad memory which is ignored
592 while (SubType != NewTy) {
593 const Type *NextSubType = 0;
594 unsigned NextSubTypeSize = 0;
595 unsigned NextPadSize = 0;
596 switch (SubType->getTypeID()) {
597 case Type::StructTyID: {
598 const StructType *STy = cast<StructType>(SubType);
599 const StructLayout &SL = *TD.getStructLayout(STy);
600 if (SL.MemberOffsets.size() > 1)
601 NextPadSize = (unsigned)SL.MemberOffsets[1];
603 NextPadSize = SubTypeSize;
604 NextSubType = STy->getElementType(0);
605 NextSubTypeSize = (unsigned)TD.getTypeSize(NextSubType);
608 case Type::ArrayTyID:
609 NextSubType = cast<ArrayType>(SubType)->getElementType();
610 NextSubTypeSize = (unsigned)TD.getTypeSize(NextSubType);
611 NextPadSize = NextSubTypeSize;
617 if (NextSubType == 0)
618 break; // In the default case, break out of the loop
620 if (NextPadSize < NewTySize)
621 break; // Don't allow shrinking to a smaller type than NewTySize
622 SubType = NextSubType;
623 SubTypeSize = NextSubTypeSize;
624 PadSize = NextPadSize;
627 // If we found the type exactly, return it...
628 if (SubType == NewTy)
631 // Check to see if we have a compatible, but different type...
632 if (NewTySize == SubTypeSize) {
633 // Check to see if this type is obviously convertible... int -> uint f.e.
634 if (NewTy->isLosslesslyConvertibleTo(SubType))
637 // Check to see if we have a pointer & integer mismatch going on here,
638 // loading a pointer as a long, for example.
640 if (SubType->isInteger() && isa<PointerType>(NewTy) ||
641 NewTy->isInteger() && isa<PointerType>(SubType))
643 } else if (NewTySize > SubTypeSize && NewTySize <= PadSize) {
644 // We are accessing the field, plus some structure padding. Ignore the
645 // structure padding.
650 if (getParentGraph()->retnodes_begin() != getParentGraph()->retnodes_end())
651 M = getParentGraph()->retnodes_begin()->first->getParent();
652 DEBUG(std::cerr << "MergeTypeInfo Folding OrigTy: ";
653 WriteTypeSymbolic(std::cerr, Ty, M) << "\n due to:";
654 WriteTypeSymbolic(std::cerr, NewTy, M) << " @ " << Offset << "!\n"
656 WriteTypeSymbolic(std::cerr, SubType, M) << "\n\n");
658 if (FoldIfIncompatible) foldNodeCompletely();
664 /// addEdgeTo - Add an edge from the current node to the specified node. This
665 /// can cause merging of nodes in the graph.
667 void DSNode::addEdgeTo(unsigned Offset, const DSNodeHandle &NH) {
668 if (NH.isNull()) return; // Nothing to do
670 DSNodeHandle &ExistingEdge = getLink(Offset);
671 if (!ExistingEdge.isNull()) {
672 // Merge the two nodes...
673 ExistingEdge.mergeWith(NH);
674 } else { // No merging to perform...
675 setLink(Offset, NH); // Just force a link in there...
680 /// MergeSortedVectors - Efficiently merge a vector into another vector where
681 /// duplicates are not allowed and both are sorted. This assumes that 'T's are
682 /// efficiently copyable and have sane comparison semantics.
684 static void MergeSortedVectors(std::vector<GlobalValue*> &Dest,
685 const std::vector<GlobalValue*> &Src) {
686 // By far, the most common cases will be the simple ones. In these cases,
687 // avoid having to allocate a temporary vector...
689 if (Src.empty()) { // Nothing to merge in...
691 } else if (Dest.empty()) { // Just copy the result in...
693 } else if (Src.size() == 1) { // Insert a single element...
694 const GlobalValue *V = Src[0];
695 std::vector<GlobalValue*>::iterator I =
696 std::lower_bound(Dest.begin(), Dest.end(), V);
697 if (I == Dest.end() || *I != Src[0]) // If not already contained...
698 Dest.insert(I, Src[0]);
699 } else if (Dest.size() == 1) {
700 GlobalValue *Tmp = Dest[0]; // Save value in temporary...
701 Dest = Src; // Copy over list...
702 std::vector<GlobalValue*>::iterator I =
703 std::lower_bound(Dest.begin(), Dest.end(), Tmp);
704 if (I == Dest.end() || *I != Tmp) // If not already contained...
708 // Make a copy to the side of Dest...
709 std::vector<GlobalValue*> Old(Dest);
711 // Make space for all of the type entries now...
712 Dest.resize(Dest.size()+Src.size());
714 // Merge the two sorted ranges together... into Dest.
715 std::merge(Old.begin(), Old.end(), Src.begin(), Src.end(), Dest.begin());
717 // Now erase any duplicate entries that may have accumulated into the
718 // vectors (because they were in both of the input sets)
719 Dest.erase(std::unique(Dest.begin(), Dest.end()), Dest.end());
723 void DSNode::mergeGlobals(const std::vector<GlobalValue*> &RHS) {
724 MergeSortedVectors(Globals, RHS);
727 // MergeNodes - Helper function for DSNode::mergeWith().
728 // This function does the hard work of merging two nodes, CurNodeH
729 // and NH after filtering out trivial cases and making sure that
730 // CurNodeH.offset >= NH.offset.
733 // Since merging may cause either node to go away, we must always
734 // use the node-handles to refer to the nodes. These node handles are
735 // automatically updated during merging, so will always provide access
736 // to the correct node after a merge.
738 void DSNode::MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH) {
739 assert(CurNodeH.getOffset() >= NH.getOffset() &&
740 "This should have been enforced in the caller.");
741 assert(CurNodeH.getNode()->getParentGraph()==NH.getNode()->getParentGraph() &&
742 "Cannot merge two nodes that are not in the same graph!");
744 // Now we know that Offset >= NH.Offset, so convert it so our "Offset" (with
745 // respect to NH.Offset) is now zero. NOffset is the distance from the base
746 // of our object that N starts from.
748 unsigned NOffset = CurNodeH.getOffset()-NH.getOffset();
749 unsigned NSize = NH.getNode()->getSize();
751 // If the two nodes are of different size, and the smaller node has the array
752 // bit set, collapse!
753 if (NSize != CurNodeH.getNode()->getSize()) {
754 #if COLLAPSE_ARRAYS_AGGRESSIVELY
755 if (NSize < CurNodeH.getNode()->getSize()) {
756 if (NH.getNode()->isArray())
757 NH.getNode()->foldNodeCompletely();
758 } else if (CurNodeH.getNode()->isArray()) {
759 NH.getNode()->foldNodeCompletely();
764 // Merge the type entries of the two nodes together...
765 if (NH.getNode()->Ty != Type::VoidTy)
766 CurNodeH.getNode()->mergeTypeInfo(NH.getNode()->Ty, NOffset);
767 assert(!CurNodeH.getNode()->isDeadNode());
769 // If we are merging a node with a completely folded node, then both nodes are
770 // now completely folded.
772 if (CurNodeH.getNode()->isNodeCompletelyFolded()) {
773 if (!NH.getNode()->isNodeCompletelyFolded()) {
774 NH.getNode()->foldNodeCompletely();
775 assert(NH.getNode() && NH.getOffset() == 0 &&
776 "folding did not make offset 0?");
777 NOffset = NH.getOffset();
778 NSize = NH.getNode()->getSize();
779 assert(NOffset == 0 && NSize == 1);
781 } else if (NH.getNode()->isNodeCompletelyFolded()) {
782 CurNodeH.getNode()->foldNodeCompletely();
783 assert(CurNodeH.getNode() && CurNodeH.getOffset() == 0 &&
784 "folding did not make offset 0?");
785 NSize = NH.getNode()->getSize();
786 NOffset = NH.getOffset();
787 assert(NOffset == 0 && NSize == 1);
790 DSNode *N = NH.getNode();
791 if (CurNodeH.getNode() == N || N == 0) return;
792 assert(!CurNodeH.getNode()->isDeadNode());
794 // Merge the NodeType information.
795 CurNodeH.getNode()->NodeType |= N->NodeType;
797 // Start forwarding to the new node!
798 N->forwardNode(CurNodeH.getNode(), NOffset);
799 assert(!CurNodeH.getNode()->isDeadNode());
801 // Make all of the outgoing links of N now be outgoing links of CurNodeH.
803 for (unsigned i = 0; i < N->getNumLinks(); ++i) {
804 DSNodeHandle &Link = N->getLink(i << DS::PointerShift);
805 if (Link.getNode()) {
806 // Compute the offset into the current node at which to
807 // merge this link. In the common case, this is a linear
808 // relation to the offset in the original node (with
809 // wrapping), but if the current node gets collapsed due to
810 // recursive merging, we must make sure to merge in all remaining
811 // links at offset zero.
812 unsigned MergeOffset = 0;
813 DSNode *CN = CurNodeH.getNode();
815 MergeOffset = ((i << DS::PointerShift)+NOffset) % CN->getSize();
816 CN->addEdgeTo(MergeOffset, Link);
820 // Now that there are no outgoing edges, all of the Links are dead.
823 // Merge the globals list...
824 if (!N->Globals.empty()) {
825 CurNodeH.getNode()->mergeGlobals(N->Globals);
827 // Delete the globals from the old node...
828 std::vector<GlobalValue*>().swap(N->Globals);
833 /// mergeWith - Merge this node and the specified node, moving all links to and
834 /// from the argument node into the current node, deleting the node argument.
835 /// Offset indicates what offset the specified node is to be merged into the
838 /// The specified node may be a null pointer (in which case, we update it to
839 /// point to this node).
841 void DSNode::mergeWith(const DSNodeHandle &NH, unsigned Offset) {
842 DSNode *N = NH.getNode();
843 if (N == this && NH.getOffset() == Offset)
846 // If the RHS is a null node, make it point to this node!
848 NH.mergeWith(DSNodeHandle(this, Offset));
852 assert(!N->isDeadNode() && !isDeadNode());
853 assert(!hasNoReferrers() && "Should not try to fold a useless node!");
856 // We cannot merge two pieces of the same node together, collapse the node
858 DEBUG(std::cerr << "Attempting to merge two chunks of"
859 << " the same node together!\n");
860 foldNodeCompletely();
864 // If both nodes are not at offset 0, make sure that we are merging the node
865 // at an later offset into the node with the zero offset.
867 if (Offset < NH.getOffset()) {
868 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
870 } else if (Offset == NH.getOffset() && getSize() < N->getSize()) {
871 // If the offsets are the same, merge the smaller node into the bigger node
872 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
876 // Ok, now we can merge the two nodes. Use a static helper that works with
877 // two node handles, since "this" may get merged away at intermediate steps.
878 DSNodeHandle CurNodeH(this, Offset);
879 DSNodeHandle NHCopy(NH);
880 DSNode::MergeNodes(CurNodeH, NHCopy);
884 //===----------------------------------------------------------------------===//
885 // ReachabilityCloner Implementation
886 //===----------------------------------------------------------------------===//
888 DSNodeHandle ReachabilityCloner::getClonedNH(const DSNodeHandle &SrcNH) {
889 if (SrcNH.isNull()) return DSNodeHandle();
890 const DSNode *SN = SrcNH.getNode();
892 DSNodeHandle &NH = NodeMap[SN];
893 if (!NH.isNull()) { // Node already mapped?
894 DSNode *NHN = NH.getNode();
895 return DSNodeHandle(NHN, NH.getOffset()+SrcNH.getOffset());
898 // If SrcNH has globals and the destination graph has one of the same globals,
899 // merge this node with the destination node, which is much more efficient.
900 if (SN->globals_begin() != SN->globals_end()) {
901 DSScalarMap &DestSM = Dest.getScalarMap();
902 for (DSNode::globals_iterator I = SN->globals_begin(),E = SN->globals_end();
904 GlobalValue *GV = *I;
905 DSScalarMap::iterator GI = DestSM.find(GV);
906 if (GI != DestSM.end() && !GI->second.isNull()) {
907 // We found one, use merge instead!
908 merge(GI->second, Src.getNodeForValue(GV));
909 assert(!NH.isNull() && "Didn't merge node!");
910 DSNode *NHN = NH.getNode();
911 return DSNodeHandle(NHN, NH.getOffset()+SrcNH.getOffset());
916 DSNode *DN = new DSNode(*SN, &Dest, true /* Null out all links */);
917 DN->maskNodeTypes(BitsToKeep);
920 // Next, recursively clone all outgoing links as necessary. Note that
921 // adding these links can cause the node to collapse itself at any time, and
922 // the current node may be merged with arbitrary other nodes. For this
923 // reason, we must always go through NH.
925 for (unsigned i = 0, e = SN->getNumLinks(); i != e; ++i) {
926 const DSNodeHandle &SrcEdge = SN->getLink(i << DS::PointerShift);
927 if (!SrcEdge.isNull()) {
928 const DSNodeHandle &DestEdge = getClonedNH(SrcEdge);
929 // Compute the offset into the current node at which to
930 // merge this link. In the common case, this is a linear
931 // relation to the offset in the original node (with
932 // wrapping), but if the current node gets collapsed due to
933 // recursive merging, we must make sure to merge in all remaining
934 // links at offset zero.
935 unsigned MergeOffset = 0;
936 DSNode *CN = NH.getNode();
937 if (CN->getSize() != 1)
938 MergeOffset = ((i << DS::PointerShift)+NH.getOffset()) % CN->getSize();
939 CN->addEdgeTo(MergeOffset, DestEdge);
943 // If this node contains any globals, make sure they end up in the scalar
944 // map with the correct offset.
945 for (DSNode::globals_iterator I = SN->globals_begin(), E = SN->globals_end();
947 GlobalValue *GV = *I;
948 const DSNodeHandle &SrcGNH = Src.getNodeForValue(GV);
949 DSNodeHandle &DestGNH = NodeMap[SrcGNH.getNode()];
950 assert(DestGNH.getNode() == NH.getNode() &&"Global mapping inconsistent");
951 Dest.getNodeForValue(GV).mergeWith(DSNodeHandle(DestGNH.getNode(),
952 DestGNH.getOffset()+SrcGNH.getOffset()));
954 NH.getNode()->mergeGlobals(SN->getGlobalsList());
956 return DSNodeHandle(NH.getNode(), NH.getOffset()+SrcNH.getOffset());
959 void ReachabilityCloner::merge(const DSNodeHandle &NH,
960 const DSNodeHandle &SrcNH) {
961 if (SrcNH.isNull()) return; // Noop
963 // If there is no destination node, just clone the source and assign the
964 // destination node to be it.
965 NH.mergeWith(getClonedNH(SrcNH));
969 // Okay, at this point, we know that we have both a destination and a source
970 // node that need to be merged. Check to see if the source node has already
972 const DSNode *SN = SrcNH.getNode();
973 DSNodeHandle &SCNH = NodeMap[SN]; // SourceClonedNodeHandle
974 if (!SCNH.isNull()) { // Node already cloned?
975 DSNode *SCNHN = SCNH.getNode();
976 NH.mergeWith(DSNodeHandle(SCNHN,
977 SCNH.getOffset()+SrcNH.getOffset()));
978 return; // Nothing to do!
981 // Okay, so the source node has not already been cloned. Instead of creating
982 // a new DSNode, only to merge it into the one we already have, try to perform
983 // the merge in-place. The only case we cannot handle here is when the offset
984 // into the existing node is less than the offset into the virtual node we are
985 // merging in. In this case, we have to extend the existing node, which
986 // requires an allocation anyway.
987 DSNode *DN = NH.getNode(); // Make sure the Offset is up-to-date
988 if (NH.getOffset() >= SrcNH.getOffset()) {
989 if (!DN->isNodeCompletelyFolded()) {
990 // Make sure the destination node is folded if the source node is folded.
991 if (SN->isNodeCompletelyFolded()) {
992 DN->foldNodeCompletely();
994 } else if (SN->getSize() != DN->getSize()) {
995 // If the two nodes are of different size, and the smaller node has the
996 // array bit set, collapse!
997 #if COLLAPSE_ARRAYS_AGGRESSIVELY
998 if (SN->getSize() < DN->getSize()) {
1000 DN->foldNodeCompletely();
1003 } else if (DN->isArray()) {
1004 DN->foldNodeCompletely();
1010 // Merge the type entries of the two nodes together...
1011 if (SN->getType() != Type::VoidTy && !DN->isNodeCompletelyFolded()) {
1012 DN->mergeTypeInfo(SN->getType(), NH.getOffset()-SrcNH.getOffset());
1017 assert(!DN->isDeadNode());
1019 // Merge the NodeType information.
1020 DN->mergeNodeFlags(SN->getNodeFlags() & BitsToKeep);
1022 // Before we start merging outgoing links and updating the scalar map, make
1023 // sure it is known that this is the representative node for the src node.
1024 SCNH = DSNodeHandle(DN, NH.getOffset()-SrcNH.getOffset());
1026 // If the source node contains any globals, make sure they end up in the
1027 // scalar map with the correct offset.
1028 if (SN->globals_begin() != SN->globals_end()) {
1029 // Update the globals in the destination node itself.
1030 DN->mergeGlobals(SN->getGlobalsList());
1032 // Update the scalar map for the graph we are merging the source node
1034 for (DSNode::globals_iterator I = SN->globals_begin(),
1035 E = SN->globals_end(); I != E; ++I) {
1036 GlobalValue *GV = *I;
1037 const DSNodeHandle &SrcGNH = Src.getNodeForValue(GV);
1038 DSNodeHandle &DestGNH = NodeMap[SrcGNH.getNode()];
1039 assert(DestGNH.getNode()==NH.getNode() &&"Global mapping inconsistent");
1040 Dest.getNodeForValue(GV).mergeWith(DSNodeHandle(DestGNH.getNode(),
1041 DestGNH.getOffset()+SrcGNH.getOffset()));
1043 NH.getNode()->mergeGlobals(SN->getGlobalsList());
1046 // We cannot handle this case without allocating a temporary node. Fall
1047 // back on being simple.
1048 DSNode *NewDN = new DSNode(*SN, &Dest, true /* Null out all links */);
1049 NewDN->maskNodeTypes(BitsToKeep);
1051 unsigned NHOffset = NH.getOffset();
1052 NH.mergeWith(DSNodeHandle(NewDN, SrcNH.getOffset()));
1054 assert(NH.getNode() &&
1055 (NH.getOffset() > NHOffset ||
1056 (NH.getOffset() == 0 && NH.getNode()->isNodeCompletelyFolded())) &&
1057 "Merging did not adjust the offset!");
1059 // Before we start merging outgoing links and updating the scalar map, make
1060 // sure it is known that this is the representative node for the src node.
1061 SCNH = DSNodeHandle(NH.getNode(), NH.getOffset()-SrcNH.getOffset());
1063 // If the source node contained any globals, make sure to create entries
1064 // in the scalar map for them!
1065 for (DSNode::globals_iterator I = SN->globals_begin(),
1066 E = SN->globals_end(); I != E; ++I) {
1067 GlobalValue *GV = *I;
1068 const DSNodeHandle &SrcGNH = Src.getNodeForValue(GV);
1069 DSNodeHandle &DestGNH = NodeMap[SrcGNH.getNode()];
1070 assert(DestGNH.getNode()==NH.getNode() &&"Global mapping inconsistent");
1071 assert(SrcGNH.getNode() == SN && "Global mapping inconsistent");
1072 Dest.getNodeForValue(GV).mergeWith(DSNodeHandle(DestGNH.getNode(),
1073 DestGNH.getOffset()+SrcGNH.getOffset()));
1078 // Next, recursively merge all outgoing links as necessary. Note that
1079 // adding these links can cause the destination node to collapse itself at
1080 // any time, and the current node may be merged with arbitrary other nodes.
1081 // For this reason, we must always go through NH.
1083 for (unsigned i = 0, e = SN->getNumLinks(); i != e; ++i) {
1084 const DSNodeHandle &SrcEdge = SN->getLink(i << DS::PointerShift);
1085 if (!SrcEdge.isNull()) {
1086 // Compute the offset into the current node at which to
1087 // merge this link. In the common case, this is a linear
1088 // relation to the offset in the original node (with
1089 // wrapping), but if the current node gets collapsed due to
1090 // recursive merging, we must make sure to merge in all remaining
1091 // links at offset zero.
1092 DSNode *CN = SCNH.getNode();
1093 unsigned MergeOffset =
1094 ((i << DS::PointerShift)+SCNH.getOffset()) % CN->getSize();
1096 DSNodeHandle Tmp = CN->getLink(MergeOffset);
1097 if (!Tmp.isNull()) {
1098 // Perform the recursive merging. Make sure to create a temporary NH,
1099 // because the Link can disappear in the process of recursive merging.
1100 merge(Tmp, SrcEdge);
1102 Tmp.mergeWith(getClonedNH(SrcEdge));
1103 // Merging this could cause all kinds of recursive things to happen,
1104 // culminating in the current node being eliminated. Since this is
1105 // possible, make sure to reaquire the link from 'CN'.
1107 unsigned MergeOffset = 0;
1108 CN = SCNH.getNode();
1109 MergeOffset = ((i << DS::PointerShift)+SCNH.getOffset()) %CN->getSize();
1110 CN->getLink(MergeOffset).mergeWith(Tmp);
1116 /// mergeCallSite - Merge the nodes reachable from the specified src call
1117 /// site into the nodes reachable from DestCS.
1118 void ReachabilityCloner::mergeCallSite(DSCallSite &DestCS,
1119 const DSCallSite &SrcCS) {
1120 merge(DestCS.getRetVal(), SrcCS.getRetVal());
1121 unsigned MinArgs = DestCS.getNumPtrArgs();
1122 if (SrcCS.getNumPtrArgs() < MinArgs) MinArgs = SrcCS.getNumPtrArgs();
1124 for (unsigned a = 0; a != MinArgs; ++a)
1125 merge(DestCS.getPtrArg(a), SrcCS.getPtrArg(a));
1127 for (unsigned a = MinArgs, e = SrcCS.getNumPtrArgs(); a != e; ++a)
1128 DestCS.addPtrArg(getClonedNH(SrcCS.getPtrArg(a)));
1132 //===----------------------------------------------------------------------===//
1133 // DSCallSite Implementation
1134 //===----------------------------------------------------------------------===//
1136 // Define here to avoid including iOther.h and BasicBlock.h in DSGraph.h
1137 Function &DSCallSite::getCaller() const {
1138 return *Site.getInstruction()->getParent()->getParent();
1141 void DSCallSite::InitNH(DSNodeHandle &NH, const DSNodeHandle &Src,
1142 ReachabilityCloner &RC) {
1143 NH = RC.getClonedNH(Src);
1146 //===----------------------------------------------------------------------===//
1147 // DSGraph Implementation
1148 //===----------------------------------------------------------------------===//
1150 /// getFunctionNames - Return a space separated list of the name of the
1151 /// functions in this graph (if any)
1152 std::string DSGraph::getFunctionNames() const {
1153 switch (getReturnNodes().size()) {
1154 case 0: return "Globals graph";
1155 case 1: return retnodes_begin()->first->getName();
1158 for (DSGraph::retnodes_iterator I = retnodes_begin();
1159 I != retnodes_end(); ++I)
1160 Return += I->first->getName() + " ";
1161 Return.erase(Return.end()-1, Return.end()); // Remove last space character
1167 DSGraph::DSGraph(const DSGraph &G, EquivalenceClasses<GlobalValue*> &ECs,
1168 unsigned CloneFlags)
1169 : GlobalsGraph(0), ScalarMap(ECs), TD(G.TD) {
1170 PrintAuxCalls = false;
1171 cloneInto(G, CloneFlags);
1174 DSGraph::~DSGraph() {
1175 FunctionCalls.clear();
1176 AuxFunctionCalls.clear();
1178 ReturnNodes.clear();
1180 // Drop all intra-node references, so that assertions don't fail...
1181 for (node_iterator NI = node_begin(), E = node_end(); NI != E; ++NI)
1182 NI->dropAllReferences();
1184 // Free all of the nodes.
1188 // dump - Allow inspection of graph in a debugger.
1189 void DSGraph::dump() const { print(std::cerr); }
1192 /// remapLinks - Change all of the Links in the current node according to the
1193 /// specified mapping.
1195 void DSNode::remapLinks(DSGraph::NodeMapTy &OldNodeMap) {
1196 for (unsigned i = 0, e = Links.size(); i != e; ++i)
1197 if (DSNode *N = Links[i].getNode()) {
1198 DSGraph::NodeMapTy::const_iterator ONMI = OldNodeMap.find(N);
1199 if (ONMI != OldNodeMap.end()) {
1200 DSNode *ONMIN = ONMI->second.getNode();
1201 Links[i].setTo(ONMIN, Links[i].getOffset()+ONMI->second.getOffset());
1206 /// addObjectToGraph - This method can be used to add global, stack, and heap
1207 /// objects to the graph. This can be used when updating DSGraphs due to the
1208 /// introduction of new temporary objects. The new object is not pointed to
1209 /// and does not point to any other objects in the graph.
1210 DSNode *DSGraph::addObjectToGraph(Value *Ptr, bool UseDeclaredType) {
1211 assert(isa<PointerType>(Ptr->getType()) && "Ptr is not a pointer!");
1212 const Type *Ty = cast<PointerType>(Ptr->getType())->getElementType();
1213 DSNode *N = new DSNode(UseDeclaredType ? Ty : 0, this);
1214 assert(ScalarMap[Ptr].isNull() && "Object already in this graph!");
1217 if (GlobalValue *GV = dyn_cast<GlobalValue>(Ptr)) {
1219 } else if (MallocInst *MI = dyn_cast<MallocInst>(Ptr)) {
1220 N->setHeapNodeMarker();
1221 } else if (AllocaInst *AI = dyn_cast<AllocaInst>(Ptr)) {
1222 N->setAllocaNodeMarker();
1224 assert(0 && "Illegal memory object input!");
1230 /// cloneInto - Clone the specified DSGraph into the current graph. The
1231 /// translated ScalarMap for the old function is filled into the ScalarMap
1232 /// for the graph, and the translated ReturnNodes map is returned into
1235 /// The CloneFlags member controls various aspects of the cloning process.
1237 void DSGraph::cloneInto(const DSGraph &G, unsigned CloneFlags) {
1238 TIME_REGION(X, "cloneInto");
1239 assert(&G != this && "Cannot clone graph into itself!");
1241 NodeMapTy OldNodeMap;
1243 // Remove alloca or mod/ref bits as specified...
1244 unsigned BitsToClear = ((CloneFlags & StripAllocaBit)? DSNode::AllocaNode : 0)
1245 | ((CloneFlags & StripModRefBits)? (DSNode::Modified | DSNode::Read) : 0)
1246 | ((CloneFlags & StripIncompleteBit)? DSNode::Incomplete : 0);
1247 BitsToClear |= DSNode::DEAD; // Clear dead flag...
1249 for (node_const_iterator I = G.node_begin(), E = G.node_end(); I != E; ++I) {
1250 assert(!I->isForwarding() &&
1251 "Forward nodes shouldn't be in node list!");
1252 DSNode *New = new DSNode(*I, this);
1253 New->maskNodeTypes(~BitsToClear);
1254 OldNodeMap[I] = New;
1258 Timer::addPeakMemoryMeasurement();
1261 // Rewrite the links in the new nodes to point into the current graph now.
1262 // Note that we don't loop over the node's list to do this. The problem is
1263 // that remaping links can cause recursive merging to happen, which means
1264 // that node_iterator's can get easily invalidated! Because of this, we
1265 // loop over the OldNodeMap, which contains all of the new nodes as the
1266 // .second element of the map elements. Also note that if we remap a node
1267 // more than once, we won't break anything.
1268 for (NodeMapTy::iterator I = OldNodeMap.begin(), E = OldNodeMap.end();
1270 I->second.getNode()->remapLinks(OldNodeMap);
1272 // Copy the scalar map... merging all of the global nodes...
1273 for (DSScalarMap::const_iterator I = G.ScalarMap.begin(),
1274 E = G.ScalarMap.end(); I != E; ++I) {
1275 DSNodeHandle &MappedNode = OldNodeMap[I->second.getNode()];
1276 DSNodeHandle &H = ScalarMap.getRawEntryRef(I->first);
1277 DSNode *MappedNodeN = MappedNode.getNode();
1278 H.mergeWith(DSNodeHandle(MappedNodeN,
1279 I->second.getOffset()+MappedNode.getOffset()));
1282 if (!(CloneFlags & DontCloneCallNodes)) {
1283 // Copy the function calls list.
1284 for (fc_iterator I = G.fc_begin(), E = G.fc_end(); I != E; ++I)
1285 FunctionCalls.push_back(DSCallSite(*I, OldNodeMap));
1288 if (!(CloneFlags & DontCloneAuxCallNodes)) {
1289 // Copy the auxiliary function calls list.
1290 for (afc_iterator I = G.afc_begin(), E = G.afc_end(); I != E; ++I)
1291 AuxFunctionCalls.push_back(DSCallSite(*I, OldNodeMap));
1294 // Map the return node pointers over...
1295 for (retnodes_iterator I = G.retnodes_begin(),
1296 E = G.retnodes_end(); I != E; ++I) {
1297 const DSNodeHandle &Ret = I->second;
1298 DSNodeHandle &MappedRet = OldNodeMap[Ret.getNode()];
1299 DSNode *MappedRetN = MappedRet.getNode();
1300 ReturnNodes.insert(std::make_pair(I->first,
1301 DSNodeHandle(MappedRetN,
1302 MappedRet.getOffset()+Ret.getOffset())));
1306 /// spliceFrom - Logically perform the operation of cloning the RHS graph into
1307 /// this graph, then clearing the RHS graph. Instead of performing this as
1308 /// two seperate operations, do it as a single, much faster, one.
1310 void DSGraph::spliceFrom(DSGraph &RHS) {
1311 // Change all of the nodes in RHS to think we are their parent.
1312 for (NodeListTy::iterator I = RHS.Nodes.begin(), E = RHS.Nodes.end();
1314 I->setParentGraph(this);
1315 // Take all of the nodes.
1316 Nodes.splice(Nodes.end(), RHS.Nodes);
1318 // Take all of the calls.
1319 FunctionCalls.splice(FunctionCalls.end(), RHS.FunctionCalls);
1320 AuxFunctionCalls.splice(AuxFunctionCalls.end(), RHS.AuxFunctionCalls);
1322 // Take all of the return nodes.
1323 if (ReturnNodes.empty()) {
1324 ReturnNodes.swap(RHS.ReturnNodes);
1326 ReturnNodes.insert(RHS.ReturnNodes.begin(), RHS.ReturnNodes.end());
1327 RHS.ReturnNodes.clear();
1330 // Merge the scalar map in.
1331 ScalarMap.spliceFrom(RHS.ScalarMap);
1334 /// spliceFrom - Copy all entries from RHS, then clear RHS.
1336 void DSScalarMap::spliceFrom(DSScalarMap &RHS) {
1337 // Special case if this is empty.
1338 if (ValueMap.empty()) {
1339 ValueMap.swap(RHS.ValueMap);
1340 GlobalSet.swap(RHS.GlobalSet);
1342 GlobalSet.insert(RHS.GlobalSet.begin(), RHS.GlobalSet.end());
1343 for (ValueMapTy::iterator I = RHS.ValueMap.begin(), E = RHS.ValueMap.end();
1345 ValueMap[I->first].mergeWith(I->second);
1346 RHS.ValueMap.clear();
1351 /// getFunctionArgumentsForCall - Given a function that is currently in this
1352 /// graph, return the DSNodeHandles that correspond to the pointer-compatible
1353 /// function arguments. The vector is filled in with the return value (or
1354 /// null if it is not pointer compatible), followed by all of the
1355 /// pointer-compatible arguments.
1356 void DSGraph::getFunctionArgumentsForCall(Function *F,
1357 std::vector<DSNodeHandle> &Args) const {
1358 Args.push_back(getReturnNodeFor(*F));
1359 for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
1361 if (isPointerType(AI->getType())) {
1362 Args.push_back(getNodeForValue(AI));
1363 assert(!Args.back().isNull() && "Pointer argument w/o scalarmap entry!?");
1368 // HackedGraphSCCFinder - This is used to find nodes that have a path from the
1369 // node to a node cloned by the ReachabilityCloner object contained. To be
1370 // extra obnoxious it ignores edges from nodes that are globals, and truncates
1371 // search at RC marked nodes. This is designed as an object so that
1372 // intermediate results can be memoized across invocations of
1373 // PathExistsToClonedNode.
1374 struct HackedGraphSCCFinder {
1375 ReachabilityCloner &RC;
1377 std::vector<const DSNode*> SCCStack;
1378 std::map<const DSNode*, std::pair<unsigned, bool> > NodeInfo;
1380 HackedGraphSCCFinder(ReachabilityCloner &rc) : RC(rc), CurNodeId(1) {
1381 // Remove null pointer as a special case.
1382 NodeInfo[0] = std::make_pair(0, false);
1385 std::pair<unsigned, bool> &VisitForSCCs(const DSNode *N);
1387 bool PathExistsToClonedNode(const DSNode *N) {
1388 return VisitForSCCs(N).second;
1391 bool PathExistsToClonedNode(const DSCallSite &CS) {
1392 if (PathExistsToClonedNode(CS.getRetVal().getNode()))
1394 for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i)
1395 if (PathExistsToClonedNode(CS.getPtrArg(i).getNode()))
1402 std::pair<unsigned, bool> &HackedGraphSCCFinder::
1403 VisitForSCCs(const DSNode *N) {
1404 std::map<const DSNode*, std::pair<unsigned, bool> >::iterator
1405 NodeInfoIt = NodeInfo.lower_bound(N);
1406 if (NodeInfoIt != NodeInfo.end() && NodeInfoIt->first == N)
1407 return NodeInfoIt->second;
1409 unsigned Min = CurNodeId++;
1410 unsigned MyId = Min;
1411 std::pair<unsigned, bool> &ThisNodeInfo =
1412 NodeInfo.insert(NodeInfoIt,
1413 std::make_pair(N, std::make_pair(MyId, false)))->second;
1415 // Base case: if we find a global, this doesn't reach the cloned graph
1417 if (N->isGlobalNode()) {
1418 ThisNodeInfo.second = false;
1419 return ThisNodeInfo;
1422 // Base case: if this does reach the cloned graph portion... it does. :)
1423 if (RC.hasClonedNode(N)) {
1424 ThisNodeInfo.second = true;
1425 return ThisNodeInfo;
1428 SCCStack.push_back(N);
1430 // Otherwise, check all successors.
1431 bool AnyDirectSuccessorsReachClonedNodes = false;
1432 for (DSNode::const_edge_iterator EI = N->edge_begin(), EE = N->edge_end();
1434 std::pair<unsigned, bool> &SuccInfo = VisitForSCCs(EI->getNode());
1435 if (SuccInfo.first < Min) Min = SuccInfo.first;
1436 AnyDirectSuccessorsReachClonedNodes |= SuccInfo.second;
1440 return ThisNodeInfo; // Part of a large SCC. Leave self on stack.
1442 if (SCCStack.back() == N) { // Special case single node SCC.
1443 SCCStack.pop_back();
1444 ThisNodeInfo.second = AnyDirectSuccessorsReachClonedNodes;
1445 return ThisNodeInfo;
1448 // Find out if any direct successors of any node reach cloned nodes.
1449 if (!AnyDirectSuccessorsReachClonedNodes)
1450 for (unsigned i = SCCStack.size()-1; SCCStack[i] != N; --i)
1451 for (DSNode::const_edge_iterator EI = N->edge_begin(), EE = N->edge_end();
1453 if (DSNode *N = EI->getNode())
1454 if (NodeInfo[N].second) {
1455 AnyDirectSuccessorsReachClonedNodes = true;
1459 // If any successor reaches a cloned node, mark all nodes in this SCC as
1460 // reaching the cloned node.
1461 if (AnyDirectSuccessorsReachClonedNodes)
1462 while (SCCStack.back() != N) {
1463 NodeInfo[SCCStack.back()].second = true;
1464 SCCStack.pop_back();
1466 SCCStack.pop_back();
1467 ThisNodeInfo.second = true;
1468 return ThisNodeInfo;
1471 /// mergeInCallFromOtherGraph - This graph merges in the minimal number of
1472 /// nodes from G2 into 'this' graph, merging the bindings specified by the
1473 /// call site (in this graph) with the bindings specified by the vector in G2.
1474 /// The two DSGraphs must be different.
1476 void DSGraph::mergeInGraph(const DSCallSite &CS,
1477 std::vector<DSNodeHandle> &Args,
1478 const DSGraph &Graph, unsigned CloneFlags) {
1479 TIME_REGION(X, "mergeInGraph");
1481 assert((CloneFlags & DontCloneCallNodes) &&
1482 "Doesn't support copying of call nodes!");
1484 // If this is not a recursive call, clone the graph into this graph...
1485 if (&Graph == this) {
1486 // Merge the return value with the return value of the context.
1487 Args[0].mergeWith(CS.getRetVal());
1489 // Resolve all of the function arguments.
1490 for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i) {
1491 if (i == Args.size()-1)
1494 // Add the link from the argument scalar to the provided value.
1495 Args[i+1].mergeWith(CS.getPtrArg(i));
1500 // Clone the callee's graph into the current graph, keeping track of where
1501 // scalars in the old graph _used_ to point, and of the new nodes matching
1502 // nodes of the old graph.
1503 ReachabilityCloner RC(*this, Graph, CloneFlags);
1505 // Map the return node pointer over.
1506 if (!CS.getRetVal().isNull())
1507 RC.merge(CS.getRetVal(), Args[0]);
1509 // Map over all of the arguments.
1510 for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i) {
1511 if (i == Args.size()-1)
1514 // Add the link from the argument scalar to the provided value.
1515 RC.merge(CS.getPtrArg(i), Args[i+1]);
1518 // We generally don't want to copy global nodes or aux calls from the callee
1519 // graph to the caller graph. However, we have to copy them if there is a
1520 // path from the node to a node we have already copied which does not go
1521 // through another global. Compute the set of node that can reach globals and
1522 // aux call nodes to copy over, then do it.
1523 std::vector<const DSCallSite*> AuxCallToCopy;
1524 std::vector<GlobalValue*> GlobalsToCopy;
1526 // NodesReachCopiedNodes - Memoize results for efficiency. Contains a
1527 // true/false value for every visited node that reaches a copied node without
1528 // going through a global.
1529 HackedGraphSCCFinder SCCFinder(RC);
1531 if (!(CloneFlags & DontCloneAuxCallNodes))
1532 for (afc_iterator I = Graph.afc_begin(), E = Graph.afc_end(); I!=E; ++I)
1533 if (SCCFinder.PathExistsToClonedNode(*I))
1534 AuxCallToCopy.push_back(&*I);
1536 const DSScalarMap &GSM = Graph.getScalarMap();
1537 for (DSScalarMap::global_iterator GI = GSM.global_begin(),
1538 E = GSM.global_end(); GI != E; ++GI) {
1539 DSNode *GlobalNode = Graph.getNodeForValue(*GI).getNode();
1540 for (DSNode::edge_iterator EI = GlobalNode->edge_begin(),
1541 EE = GlobalNode->edge_end(); EI != EE; ++EI)
1542 if (SCCFinder.PathExistsToClonedNode(EI->getNode())) {
1543 GlobalsToCopy.push_back(*GI);
1548 // Copy aux calls that are needed.
1549 for (unsigned i = 0, e = AuxCallToCopy.size(); i != e; ++i)
1550 AuxFunctionCalls.push_back(DSCallSite(*AuxCallToCopy[i], RC));
1552 // Copy globals that are needed.
1553 for (unsigned i = 0, e = GlobalsToCopy.size(); i != e; ++i)
1554 RC.getClonedNH(Graph.getNodeForValue(GlobalsToCopy[i]));
1559 /// mergeInGraph - The method is used for merging graphs together. If the
1560 /// argument graph is not *this, it makes a clone of the specified graph, then
1561 /// merges the nodes specified in the call site with the formal arguments in the
1564 void DSGraph::mergeInGraph(const DSCallSite &CS, Function &F,
1565 const DSGraph &Graph, unsigned CloneFlags) {
1566 // Set up argument bindings.
1567 std::vector<DSNodeHandle> Args;
1568 Graph.getFunctionArgumentsForCall(&F, Args);
1570 mergeInGraph(CS, Args, Graph, CloneFlags);
1573 /// getCallSiteForArguments - Get the arguments and return value bindings for
1574 /// the specified function in the current graph.
1576 DSCallSite DSGraph::getCallSiteForArguments(Function &F) const {
1577 std::vector<DSNodeHandle> Args;
1579 for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I)
1580 if (isPointerType(I->getType()))
1581 Args.push_back(getNodeForValue(I));
1583 return DSCallSite(CallSite(), getReturnNodeFor(F), &F, Args);
1586 /// getDSCallSiteForCallSite - Given an LLVM CallSite object that is live in
1587 /// the context of this graph, return the DSCallSite for it.
1588 DSCallSite DSGraph::getDSCallSiteForCallSite(CallSite CS) const {
1589 DSNodeHandle RetVal;
1590 Instruction *I = CS.getInstruction();
1591 if (isPointerType(I->getType()))
1592 RetVal = getNodeForValue(I);
1594 std::vector<DSNodeHandle> Args;
1595 Args.reserve(CS.arg_end()-CS.arg_begin());
1597 // Calculate the arguments vector...
1598 for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); I != E; ++I)
1599 if (isPointerType((*I)->getType()))
1600 if (isa<ConstantPointerNull>(*I))
1601 Args.push_back(DSNodeHandle());
1603 Args.push_back(getNodeForValue(*I));
1605 // Add a new function call entry...
1606 if (Function *F = CS.getCalledFunction())
1607 return DSCallSite(CS, RetVal, F, Args);
1609 return DSCallSite(CS, RetVal,
1610 getNodeForValue(CS.getCalledValue()).getNode(), Args);
1615 // markIncompleteNodes - Mark the specified node as having contents that are not
1616 // known with the current analysis we have performed. Because a node makes all
1617 // of the nodes it can reach incomplete if the node itself is incomplete, we
1618 // must recursively traverse the data structure graph, marking all reachable
1619 // nodes as incomplete.
1621 static void markIncompleteNode(DSNode *N) {
1622 // Stop recursion if no node, or if node already marked...
1623 if (N == 0 || N->isIncomplete()) return;
1625 // Actually mark the node
1626 N->setIncompleteMarker();
1628 // Recursively process children...
1629 for (DSNode::edge_iterator I = N->edge_begin(),E = N->edge_end(); I != E; ++I)
1630 if (DSNode *DSN = I->getNode())
1631 markIncompleteNode(DSN);
1634 static void markIncomplete(DSCallSite &Call) {
1635 // Then the return value is certainly incomplete!
1636 markIncompleteNode(Call.getRetVal().getNode());
1638 // All objects pointed to by function arguments are incomplete!
1639 for (unsigned i = 0, e = Call.getNumPtrArgs(); i != e; ++i)
1640 markIncompleteNode(Call.getPtrArg(i).getNode());
1643 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
1644 // modified by other functions that have not been resolved yet. This marks
1645 // nodes that are reachable through three sources of "unknownness":
1647 // Global Variables, Function Calls, and Incoming Arguments
1649 // For any node that may have unknown components (because something outside the
1650 // scope of current analysis may have modified it), the 'Incomplete' flag is
1651 // added to the NodeType.
1653 void DSGraph::markIncompleteNodes(unsigned Flags) {
1654 // Mark any incoming arguments as incomplete.
1655 if (Flags & DSGraph::MarkFormalArgs)
1656 for (ReturnNodesTy::iterator FI = ReturnNodes.begin(), E =ReturnNodes.end();
1658 Function &F = *FI->first;
1659 for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end();
1661 if (isPointerType(I->getType()))
1662 markIncompleteNode(getNodeForValue(I).getNode());
1663 markIncompleteNode(FI->second.getNode());
1666 // Mark stuff passed into functions calls as being incomplete.
1667 if (!shouldPrintAuxCalls())
1668 for (std::list<DSCallSite>::iterator I = FunctionCalls.begin(),
1669 E = FunctionCalls.end(); I != E; ++I)
1672 for (std::list<DSCallSite>::iterator I = AuxFunctionCalls.begin(),
1673 E = AuxFunctionCalls.end(); I != E; ++I)
1676 // Mark all global nodes as incomplete.
1677 for (DSScalarMap::global_iterator I = ScalarMap.global_begin(),
1678 E = ScalarMap.global_end(); I != E; ++I)
1679 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(*I))
1680 if (!GV->hasInitializer() || // Always mark external globals incomp.
1681 (!GV->isConstant() && (Flags & DSGraph::IgnoreGlobals) == 0))
1682 markIncompleteNode(ScalarMap[GV].getNode());
1685 static inline void killIfUselessEdge(DSNodeHandle &Edge) {
1686 if (DSNode *N = Edge.getNode()) // Is there an edge?
1687 if (N->getNumReferrers() == 1) // Does it point to a lonely node?
1688 // No interesting info?
1689 if ((N->getNodeFlags() & ~DSNode::Incomplete) == 0 &&
1690 N->getType() == Type::VoidTy && !N->isNodeCompletelyFolded())
1691 Edge.setTo(0, 0); // Kill the edge!
1694 static inline bool nodeContainsExternalFunction(const DSNode *N) {
1695 std::vector<Function*> Funcs;
1696 N->addFullFunctionList(Funcs);
1697 for (unsigned i = 0, e = Funcs.size(); i != e; ++i)
1698 if (Funcs[i]->isExternal()) return true;
1702 static void removeIdenticalCalls(std::list<DSCallSite> &Calls) {
1703 // Remove trivially identical function calls
1704 Calls.sort(); // Sort by callee as primary key!
1706 // Scan the call list cleaning it up as necessary...
1707 DSNodeHandle LastCalleeNode;
1708 Function *LastCalleeFunc = 0;
1709 unsigned NumDuplicateCalls = 0;
1710 bool LastCalleeContainsExternalFunction = false;
1712 unsigned NumDeleted = 0;
1713 for (std::list<DSCallSite>::iterator I = Calls.begin(), E = Calls.end();
1715 DSCallSite &CS = *I;
1716 std::list<DSCallSite>::iterator OldIt = I++;
1718 if (!CS.isIndirectCall()) {
1721 DSNode *Callee = CS.getCalleeNode();
1723 // If the Callee is a useless edge, this must be an unreachable call site,
1725 if (Callee->getNumReferrers() == 1 && Callee->isComplete() &&
1726 Callee->getGlobalsList().empty()) { // No useful info?
1728 std::cerr << "WARNING: Useless call site found.\n";
1735 // If the last call site in the list has the same callee as this one, and
1736 // if the callee contains an external function, it will never be
1737 // resolvable, just merge the call sites.
1738 if (!LastCalleeNode.isNull() && LastCalleeNode.getNode() == Callee) {
1739 LastCalleeContainsExternalFunction =
1740 nodeContainsExternalFunction(Callee);
1742 std::list<DSCallSite>::iterator PrevIt = OldIt;
1744 PrevIt->mergeWith(CS);
1746 // No need to keep this call anymore.
1751 LastCalleeNode = Callee;
1755 // If the return value or any arguments point to a void node with no
1756 // information at all in it, and the call node is the only node to point
1757 // to it, remove the edge to the node (killing the node).
1759 killIfUselessEdge(CS.getRetVal());
1760 for (unsigned a = 0, e = CS.getNumPtrArgs(); a != e; ++a)
1761 killIfUselessEdge(CS.getPtrArg(a));
1764 // If this call site calls the same function as the last call site, and if
1765 // the function pointer contains an external function, this node will
1766 // never be resolved. Merge the arguments of the call node because no
1767 // information will be lost.
1769 if ((CS.isDirectCall() && CS.getCalleeFunc() == LastCalleeFunc) ||
1770 (CS.isIndirectCall() && CS.getCalleeNode() == LastCalleeNode)) {
1771 ++NumDuplicateCalls;
1772 if (NumDuplicateCalls == 1) {
1774 LastCalleeContainsExternalFunction =
1775 nodeContainsExternalFunction(LastCalleeNode);
1777 LastCalleeContainsExternalFunction = LastCalleeFunc->isExternal();
1780 // It is not clear why, but enabling this code makes DSA really
1781 // sensitive to node forwarding. Basically, with this enabled, DSA
1782 // performs different number of inlinings based on which nodes are
1783 // forwarding or not. This is clearly a problem, so this code is
1784 // disabled until this can be resolved.
1786 if (LastCalleeContainsExternalFunction
1789 // This should be more than enough context sensitivity!
1790 // FIXME: Evaluate how many times this is tripped!
1791 NumDuplicateCalls > 20
1795 std::list<DSCallSite>::iterator PrevIt = OldIt;
1797 PrevIt->mergeWith(CS);
1799 // No need to keep this call anymore.
1806 if (CS.isDirectCall()) {
1807 LastCalleeFunc = CS.getCalleeFunc();
1810 LastCalleeNode = CS.getCalleeNode();
1813 NumDuplicateCalls = 0;
1817 if (I != Calls.end() && CS == *I) {
1825 // Resort now that we simplified things.
1828 // Now that we are in sorted order, eliminate duplicates.
1829 std::list<DSCallSite>::iterator CI = Calls.begin(), CE = Calls.end();
1832 std::list<DSCallSite>::iterator OldIt = CI++;
1833 if (CI == CE) break;
1835 // If this call site is now the same as the previous one, we can delete it
1837 if (*OldIt == *CI) {
1844 //Calls.erase(std::unique(Calls.begin(), Calls.end()), Calls.end());
1846 // Track the number of call nodes merged away...
1847 NumCallNodesMerged += NumDeleted;
1849 DEBUG(if (NumDeleted)
1850 std::cerr << "Merged " << NumDeleted << " call nodes.\n";);
1854 // removeTriviallyDeadNodes - After the graph has been constructed, this method
1855 // removes all unreachable nodes that are created because they got merged with
1856 // other nodes in the graph. These nodes will all be trivially unreachable, so
1857 // we don't have to perform any non-trivial analysis here.
1859 void DSGraph::removeTriviallyDeadNodes() {
1860 TIME_REGION(X, "removeTriviallyDeadNodes");
1863 /// NOTE: This code is disabled. This slows down DSA on 177.mesa
1866 // Loop over all of the nodes in the graph, calling getNode on each field.
1867 // This will cause all nodes to update their forwarding edges, causing
1868 // forwarded nodes to be delete-able.
1869 { TIME_REGION(X, "removeTriviallyDeadNodes:node_iterate");
1870 for (node_iterator NI = node_begin(), E = node_end(); NI != E; ++NI) {
1872 for (unsigned l = 0, e = N.getNumLinks(); l != e; ++l)
1873 N.getLink(l*N.getPointerSize()).getNode();
1877 // NOTE: This code is disabled. Though it should, in theory, allow us to
1878 // remove more nodes down below, the scan of the scalar map is incredibly
1879 // expensive for certain programs (with large SCCs). In the future, if we can
1880 // make the scalar map scan more efficient, then we can reenable this.
1881 { TIME_REGION(X, "removeTriviallyDeadNodes:scalarmap");
1883 // Likewise, forward any edges from the scalar nodes. While we are at it,
1884 // clean house a bit.
1885 for (DSScalarMap::iterator I = ScalarMap.begin(),E = ScalarMap.end();I != E;){
1886 I->second.getNode();
1891 bool isGlobalsGraph = !GlobalsGraph;
1893 for (NodeListTy::iterator NI = Nodes.begin(), E = Nodes.end(); NI != E; ) {
1896 // Do not remove *any* global nodes in the globals graph.
1897 // This is a special case because such nodes may not have I, M, R flags set.
1898 if (Node.isGlobalNode() && isGlobalsGraph) {
1903 if (Node.isComplete() && !Node.isModified() && !Node.isRead()) {
1904 // This is a useless node if it has no mod/ref info (checked above),
1905 // outgoing edges (which it cannot, as it is not modified in this
1906 // context), and it has no incoming edges. If it is a global node it may
1907 // have all of these properties and still have incoming edges, due to the
1908 // scalar map, so we check those now.
1910 if (Node.getNumReferrers() == Node.getGlobalsList().size()) {
1911 const std::vector<GlobalValue*> &Globals = Node.getGlobalsList();
1913 // Loop through and make sure all of the globals are referring directly
1915 for (unsigned j = 0, e = Globals.size(); j != e; ++j) {
1916 DSNode *N = getNodeForValue(Globals[j]).getNode();
1917 assert(N == &Node && "ScalarMap doesn't match globals list!");
1920 // Make sure NumReferrers still agrees, if so, the node is truly dead.
1921 if (Node.getNumReferrers() == Globals.size()) {
1922 for (unsigned j = 0, e = Globals.size(); j != e; ++j)
1923 ScalarMap.erase(Globals[j]);
1924 Node.makeNodeDead();
1925 ++NumTrivialGlobalDNE;
1930 if (Node.getNodeFlags() == 0 && Node.hasNoReferrers()) {
1931 // This node is dead!
1932 NI = Nodes.erase(NI); // Erase & remove from node list.
1939 removeIdenticalCalls(FunctionCalls);
1940 removeIdenticalCalls(AuxFunctionCalls);
1944 /// markReachableNodes - This method recursively traverses the specified
1945 /// DSNodes, marking any nodes which are reachable. All reachable nodes it adds
1946 /// to the set, which allows it to only traverse visited nodes once.
1948 void DSNode::markReachableNodes(hash_set<const DSNode*> &ReachableNodes) const {
1949 if (this == 0) return;
1950 assert(getForwardNode() == 0 && "Cannot mark a forwarded node!");
1951 if (ReachableNodes.insert(this).second) // Is newly reachable?
1952 for (DSNode::const_edge_iterator I = edge_begin(), E = edge_end();
1954 I->getNode()->markReachableNodes(ReachableNodes);
1957 void DSCallSite::markReachableNodes(hash_set<const DSNode*> &Nodes) const {
1958 getRetVal().getNode()->markReachableNodes(Nodes);
1959 if (isIndirectCall()) getCalleeNode()->markReachableNodes(Nodes);
1961 for (unsigned i = 0, e = getNumPtrArgs(); i != e; ++i)
1962 getPtrArg(i).getNode()->markReachableNodes(Nodes);
1965 // CanReachAliveNodes - Simple graph walker that recursively traverses the graph
1966 // looking for a node that is marked alive. If an alive node is found, return
1967 // true, otherwise return false. If an alive node is reachable, this node is
1968 // marked as alive...
1970 static bool CanReachAliveNodes(DSNode *N, hash_set<const DSNode*> &Alive,
1971 hash_set<const DSNode*> &Visited,
1972 bool IgnoreGlobals) {
1973 if (N == 0) return false;
1974 assert(N->getForwardNode() == 0 && "Cannot mark a forwarded node!");
1976 // If this is a global node, it will end up in the globals graph anyway, so we
1977 // don't need to worry about it.
1978 if (IgnoreGlobals && N->isGlobalNode()) return false;
1980 // If we know that this node is alive, return so!
1981 if (Alive.count(N)) return true;
1983 // Otherwise, we don't think the node is alive yet, check for infinite
1985 if (Visited.count(N)) return false; // Found a cycle
1986 Visited.insert(N); // No recursion, insert into Visited...
1988 for (DSNode::edge_iterator I = N->edge_begin(),E = N->edge_end(); I != E; ++I)
1989 if (CanReachAliveNodes(I->getNode(), Alive, Visited, IgnoreGlobals)) {
1990 N->markReachableNodes(Alive);
1996 // CallSiteUsesAliveArgs - Return true if the specified call site can reach any
1999 static bool CallSiteUsesAliveArgs(const DSCallSite &CS,
2000 hash_set<const DSNode*> &Alive,
2001 hash_set<const DSNode*> &Visited,
2002 bool IgnoreGlobals) {
2003 if (CanReachAliveNodes(CS.getRetVal().getNode(), Alive, Visited,
2006 if (CS.isIndirectCall() &&
2007 CanReachAliveNodes(CS.getCalleeNode(), Alive, Visited, IgnoreGlobals))
2009 for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i)
2010 if (CanReachAliveNodes(CS.getPtrArg(i).getNode(), Alive, Visited,
2016 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
2017 // subgraphs that are unreachable. This often occurs because the data
2018 // structure doesn't "escape" into it's caller, and thus should be eliminated
2019 // from the caller's graph entirely. This is only appropriate to use when
2022 void DSGraph::removeDeadNodes(unsigned Flags) {
2023 DEBUG(AssertGraphOK(); if (GlobalsGraph) GlobalsGraph->AssertGraphOK());
2025 // Reduce the amount of work we have to do... remove dummy nodes left over by
2027 removeTriviallyDeadNodes();
2029 TIME_REGION(X, "removeDeadNodes");
2031 // FIXME: Merge non-trivially identical call nodes...
2033 // Alive - a set that holds all nodes found to be reachable/alive.
2034 hash_set<const DSNode*> Alive;
2035 std::vector<std::pair<Value*, DSNode*> > GlobalNodes;
2037 // Copy and merge all information about globals to the GlobalsGraph if this is
2038 // not a final pass (where unreachable globals are removed).
2040 // Strip all alloca bits since the current function is only for the BU pass.
2041 // Strip all incomplete bits since they are short-lived properties and they
2042 // will be correctly computed when rematerializing nodes into the functions.
2044 ReachabilityCloner GGCloner(*GlobalsGraph, *this, DSGraph::StripAllocaBit |
2045 DSGraph::StripIncompleteBit);
2047 // Mark all nodes reachable by (non-global) scalar nodes as alive...
2048 { TIME_REGION(Y, "removeDeadNodes:scalarscan");
2049 for (DSScalarMap::iterator I = ScalarMap.begin(), E = ScalarMap.end();
2051 if (isa<GlobalValue>(I->first)) { // Keep track of global nodes
2052 assert(!I->second.isNull() && "Null global node?");
2053 assert(I->second.getNode()->isGlobalNode() && "Should be a global node!");
2054 GlobalNodes.push_back(std::make_pair(I->first, I->second.getNode()));
2056 // Make sure that all globals are cloned over as roots.
2057 if (!(Flags & DSGraph::RemoveUnreachableGlobals) && GlobalsGraph) {
2058 DSGraph::ScalarMapTy::iterator SMI =
2059 GlobalsGraph->getScalarMap().find(I->first);
2060 if (SMI != GlobalsGraph->getScalarMap().end())
2061 GGCloner.merge(SMI->second, I->second);
2063 GGCloner.getClonedNH(I->second);
2066 I->second.getNode()->markReachableNodes(Alive);
2070 // The return values are alive as well.
2071 for (ReturnNodesTy::iterator I = ReturnNodes.begin(), E = ReturnNodes.end();
2073 I->second.getNode()->markReachableNodes(Alive);
2075 // Mark any nodes reachable by primary calls as alive...
2076 for (fc_iterator I = fc_begin(), E = fc_end(); I != E; ++I)
2077 I->markReachableNodes(Alive);
2080 // Now find globals and aux call nodes that are already live or reach a live
2081 // value (which makes them live in turn), and continue till no more are found.
2084 hash_set<const DSNode*> Visited;
2085 hash_set<const DSCallSite*> AuxFCallsAlive;
2088 // If any global node points to a non-global that is "alive", the global is
2089 // "alive" as well... Remove it from the GlobalNodes list so we only have
2090 // unreachable globals in the list.
2093 if (!(Flags & DSGraph::RemoveUnreachableGlobals))
2094 for (unsigned i = 0; i != GlobalNodes.size(); ++i)
2095 if (CanReachAliveNodes(GlobalNodes[i].second, Alive, Visited,
2096 Flags & DSGraph::RemoveUnreachableGlobals)) {
2097 std::swap(GlobalNodes[i--], GlobalNodes.back()); // Move to end to...
2098 GlobalNodes.pop_back(); // erase efficiently
2102 // Mark only unresolvable call nodes for moving to the GlobalsGraph since
2103 // call nodes that get resolved will be difficult to remove from that graph.
2104 // The final unresolved call nodes must be handled specially at the end of
2105 // the BU pass (i.e., in main or other roots of the call graph).
2106 for (afc_iterator CI = afc_begin(), E = afc_end(); CI != E; ++CI)
2107 if (!AuxFCallsAlive.count(&*CI) &&
2108 (CI->isIndirectCall()
2109 || CallSiteUsesAliveArgs(*CI, Alive, Visited,
2110 Flags & DSGraph::RemoveUnreachableGlobals))) {
2111 CI->markReachableNodes(Alive);
2112 AuxFCallsAlive.insert(&*CI);
2117 // Move dead aux function calls to the end of the list
2118 unsigned CurIdx = 0;
2119 for (std::list<DSCallSite>::iterator CI = AuxFunctionCalls.begin(),
2120 E = AuxFunctionCalls.end(); CI != E; )
2121 if (AuxFCallsAlive.count(&*CI))
2124 // Copy and merge global nodes and dead aux call nodes into the
2125 // GlobalsGraph, and all nodes reachable from those nodes. Update their
2126 // target pointers using the GGCloner.
2128 if (!(Flags & DSGraph::RemoveUnreachableGlobals))
2129 GlobalsGraph->AuxFunctionCalls.push_back(DSCallSite(*CI, GGCloner));
2131 AuxFunctionCalls.erase(CI++);
2134 // We are finally done with the GGCloner so we can destroy it.
2137 // At this point, any nodes which are visited, but not alive, are nodes
2138 // which can be removed. Loop over all nodes, eliminating completely
2139 // unreachable nodes.
2141 std::vector<DSNode*> DeadNodes;
2142 DeadNodes.reserve(Nodes.size());
2143 for (NodeListTy::iterator NI = Nodes.begin(), E = Nodes.end(); NI != E;) {
2145 assert(!N->isForwarding() && "Forwarded node in nodes list?");
2147 if (!Alive.count(N)) {
2149 assert(!N->isForwarding() && "Cannot remove a forwarding node!");
2150 DeadNodes.push_back(N);
2151 N->dropAllReferences();
2156 // Remove all unreachable globals from the ScalarMap.
2157 // If flag RemoveUnreachableGlobals is set, GlobalNodes has only dead nodes.
2158 // In either case, the dead nodes will not be in the set Alive.
2159 for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
2160 if (!Alive.count(GlobalNodes[i].second))
2161 ScalarMap.erase(GlobalNodes[i].first);
2163 assert((Flags & DSGraph::RemoveUnreachableGlobals) && "non-dead global");
2165 // Delete all dead nodes now since their referrer counts are zero.
2166 for (unsigned i = 0, e = DeadNodes.size(); i != e; ++i)
2167 delete DeadNodes[i];
2169 DEBUG(AssertGraphOK(); GlobalsGraph->AssertGraphOK());
2172 void DSGraph::AssertNodeContainsGlobal(const DSNode *N, GlobalValue *GV) const {
2173 assert(std::find(N->globals_begin(),N->globals_end(), GV) !=
2174 N->globals_end() && "Global value not in node!");
2177 void DSGraph::AssertCallSiteInGraph(const DSCallSite &CS) const {
2178 if (CS.isIndirectCall()) {
2179 AssertNodeInGraph(CS.getCalleeNode());
2181 if (CS.getNumPtrArgs() && CS.getCalleeNode() == CS.getPtrArg(0).getNode() &&
2182 CS.getCalleeNode() && CS.getCalleeNode()->getGlobals().empty())
2183 std::cerr << "WARNING: WEIRD CALL SITE FOUND!\n";
2186 AssertNodeInGraph(CS.getRetVal().getNode());
2187 for (unsigned j = 0, e = CS.getNumPtrArgs(); j != e; ++j)
2188 AssertNodeInGraph(CS.getPtrArg(j).getNode());
2191 void DSGraph::AssertCallNodesInGraph() const {
2192 for (fc_iterator I = fc_begin(), E = fc_end(); I != E; ++I)
2193 AssertCallSiteInGraph(*I);
2195 void DSGraph::AssertAuxCallNodesInGraph() const {
2196 for (afc_iterator I = afc_begin(), E = afc_end(); I != E; ++I)
2197 AssertCallSiteInGraph(*I);
2200 void DSGraph::AssertGraphOK() const {
2201 for (node_const_iterator NI = node_begin(), E = node_end(); NI != E; ++NI)
2204 for (ScalarMapTy::const_iterator I = ScalarMap.begin(),
2205 E = ScalarMap.end(); I != E; ++I) {
2206 assert(!I->second.isNull() && "Null node in scalarmap!");
2207 AssertNodeInGraph(I->second.getNode());
2208 if (GlobalValue *GV = dyn_cast<GlobalValue>(I->first)) {
2209 assert(I->second.getNode()->isGlobalNode() &&
2210 "Global points to node, but node isn't global?");
2211 AssertNodeContainsGlobal(I->second.getNode(), GV);
2214 AssertCallNodesInGraph();
2215 AssertAuxCallNodesInGraph();
2217 // Check that all pointer arguments to any functions in this graph have
2219 for (ReturnNodesTy::const_iterator RI = ReturnNodes.begin(),
2220 E = ReturnNodes.end();
2222 Function &F = *RI->first;
2223 for (Function::arg_iterator AI = F.arg_begin(); AI != F.arg_end(); ++AI)
2224 if (isPointerType(AI->getType()))
2225 assert(!getNodeForValue(AI).isNull() &&
2226 "Pointer argument must be in the scalar map!");
2230 /// computeNodeMapping - Given roots in two different DSGraphs, traverse the
2231 /// nodes reachable from the two graphs, computing the mapping of nodes from the
2232 /// first to the second graph. This mapping may be many-to-one (i.e. the first
2233 /// graph may have multiple nodes representing one node in the second graph),
2234 /// but it will not work if there is a one-to-many or many-to-many mapping.
2236 void DSGraph::computeNodeMapping(const DSNodeHandle &NH1,
2237 const DSNodeHandle &NH2, NodeMapTy &NodeMap,
2238 bool StrictChecking) {
2239 DSNode *N1 = NH1.getNode(), *N2 = NH2.getNode();
2240 if (N1 == 0 || N2 == 0) return;
2242 DSNodeHandle &Entry = NodeMap[N1];
2243 if (!Entry.isNull()) {
2244 // Termination of recursion!
2245 if (StrictChecking) {
2246 assert(Entry.getNode() == N2 && "Inconsistent mapping detected!");
2247 assert((Entry.getOffset() == (NH2.getOffset()-NH1.getOffset()) ||
2248 Entry.getNode()->isNodeCompletelyFolded()) &&
2249 "Inconsistent mapping detected!");
2254 Entry.setTo(N2, NH2.getOffset()-NH1.getOffset());
2256 // Loop over all of the fields that N1 and N2 have in common, recursively
2257 // mapping the edges together now.
2258 int N2Idx = NH2.getOffset()-NH1.getOffset();
2259 unsigned N2Size = N2->getSize();
2260 if (N2Size == 0) return; // No edges to map to.
2262 for (unsigned i = 0, e = N1->getSize(); i < e; i += DS::PointerSize) {
2263 const DSNodeHandle &N1NH = N1->getLink(i);
2264 // Don't call N2->getLink if not needed (avoiding crash if N2Idx is not
2266 if (!N1NH.isNull()) {
2267 if (unsigned(N2Idx)+i < N2Size)
2268 computeNodeMapping(N1NH, N2->getLink(N2Idx+i), NodeMap);
2270 computeNodeMapping(N1NH,
2271 N2->getLink(unsigned(N2Idx+i) % N2Size), NodeMap);
2277 /// computeGToGGMapping - Compute the mapping of nodes in the global graph to
2278 /// nodes in this graph.
2279 void DSGraph::computeGToGGMapping(NodeMapTy &NodeMap) {
2280 DSGraph &GG = *getGlobalsGraph();
2282 DSScalarMap &SM = getScalarMap();
2283 for (DSScalarMap::global_iterator I = SM.global_begin(),
2284 E = SM.global_end(); I != E; ++I)
2285 DSGraph::computeNodeMapping(SM[*I], GG.getNodeForValue(*I), NodeMap);
2288 /// computeGGToGMapping - Compute the mapping of nodes in the global graph to
2289 /// nodes in this graph. Note that any uses of this method are probably bugs,
2290 /// unless it is known that the globals graph has been merged into this graph!
2291 void DSGraph::computeGGToGMapping(InvNodeMapTy &InvNodeMap) {
2293 computeGToGGMapping(NodeMap);
2295 while (!NodeMap.empty()) {
2296 InvNodeMap.insert(std::make_pair(NodeMap.begin()->second,
2297 NodeMap.begin()->first));
2298 NodeMap.erase(NodeMap.begin());
2303 /// computeCalleeCallerMapping - Given a call from a function in the current
2304 /// graph to the 'Callee' function (which lives in 'CalleeGraph'), compute the
2305 /// mapping of nodes from the callee to nodes in the caller.
2306 void DSGraph::computeCalleeCallerMapping(DSCallSite CS, const Function &Callee,
2307 DSGraph &CalleeGraph,
2308 NodeMapTy &NodeMap) {
2310 DSCallSite CalleeArgs =
2311 CalleeGraph.getCallSiteForArguments(const_cast<Function&>(Callee));
2313 computeNodeMapping(CalleeArgs.getRetVal(), CS.getRetVal(), NodeMap);
2315 unsigned NumArgs = CS.getNumPtrArgs();
2316 if (NumArgs > CalleeArgs.getNumPtrArgs())
2317 NumArgs = CalleeArgs.getNumPtrArgs();
2319 for (unsigned i = 0; i != NumArgs; ++i)
2320 computeNodeMapping(CalleeArgs.getPtrArg(i), CS.getPtrArg(i), NodeMap);
2322 // Map the nodes that are pointed to by globals.
2323 DSScalarMap &CalleeSM = CalleeGraph.getScalarMap();
2324 DSScalarMap &CallerSM = getScalarMap();
2326 if (CalleeSM.global_size() >= CallerSM.global_size()) {
2327 for (DSScalarMap::global_iterator GI = CallerSM.global_begin(),
2328 E = CallerSM.global_end(); GI != E; ++GI)
2329 if (CalleeSM.global_count(*GI))
2330 computeNodeMapping(CalleeSM[*GI], CallerSM[*GI], NodeMap);
2332 for (DSScalarMap::global_iterator GI = CalleeSM.global_begin(),
2333 E = CalleeSM.global_end(); GI != E; ++GI)
2334 if (CallerSM.global_count(*GI))
2335 computeNodeMapping(CalleeSM[*GI], CallerSM[*GI], NodeMap);