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/DSGraph.h"
15 #include "llvm/Function.h"
16 #include "llvm/iOther.h"
17 #include "llvm/DerivedTypes.h"
18 #include "llvm/Target/TargetData.h"
19 #include "llvm/Assembly/Writer.h"
20 #include "Support/Debug.h"
21 #include "Support/STLExtras.h"
22 #include "Support/Statistic.h"
23 #include "Support/Timer.h"
27 Statistic<> NumFolds ("dsnode", "Number of nodes completely folded");
28 Statistic<> NumCallNodesMerged("dsnode", "Number of call nodes merged");
31 namespace DS { // TODO: FIXME
36 DSNode *DSNodeHandle::HandleForwarding() const {
37 assert(!N->ForwardNH.isNull() && "Can only be invoked if forwarding!");
39 // Handle node forwarding here!
40 DSNode *Next = N->ForwardNH.getNode(); // Cause recursive shrinkage
41 Offset += N->ForwardNH.getOffset();
43 if (--N->NumReferrers == 0) {
44 // Removing the last referrer to the node, sever the forwarding link
50 if (N->Size <= Offset) {
51 assert(N->Size <= 1 && "Forwarded to shrunk but not collapsed node?");
57 //===----------------------------------------------------------------------===//
58 // DSNode Implementation
59 //===----------------------------------------------------------------------===//
61 DSNode::DSNode(const Type *T, DSGraph *G)
62 : NumReferrers(0), Size(0), ParentGraph(G), Ty(Type::VoidTy), NodeType(0) {
63 // Add the type entry if it is specified...
64 if (T) mergeTypeInfo(T, 0);
65 G->getNodes().push_back(this);
68 // DSNode copy constructor... do not copy over the referrers list!
69 DSNode::DSNode(const DSNode &N, DSGraph *G)
70 : NumReferrers(0), Size(N.Size), ParentGraph(G),
71 Ty(N.Ty), Links(N.Links), Globals(N.Globals), NodeType(N.NodeType) {
72 G->getNodes().push_back(this);
75 void DSNode::assertOK() const {
76 assert((Ty != Type::VoidTy ||
77 Ty == Type::VoidTy && (Size == 0 ||
78 (NodeType & DSNode::Array))) &&
81 assert(ParentGraph && "Node has no parent?");
82 const DSGraph::ScalarMapTy &SM = ParentGraph->getScalarMap();
83 for (unsigned i = 0, e = Globals.size(); i != e; ++i) {
84 assert(SM.find(Globals[i]) != SM.end());
85 assert(SM.find(Globals[i])->second.getNode() == this);
89 /// forwardNode - Mark this node as being obsolete, and all references to it
90 /// should be forwarded to the specified node and offset.
92 void DSNode::forwardNode(DSNode *To, unsigned Offset) {
93 assert(this != To && "Cannot forward a node to itself!");
94 assert(ForwardNH.isNull() && "Already forwarding from this node!");
95 if (To->Size <= 1) Offset = 0;
96 assert((Offset < To->Size || (Offset == To->Size && Offset == 0)) &&
97 "Forwarded offset is wrong!");
98 ForwardNH.setNode(To);
99 ForwardNH.setOffset(Offset);
105 // addGlobal - Add an entry for a global value to the Globals list. This also
106 // marks the node with the 'G' flag if it does not already have it.
108 void DSNode::addGlobal(GlobalValue *GV) {
109 // Keep the list sorted.
110 std::vector<GlobalValue*>::iterator I =
111 std::lower_bound(Globals.begin(), Globals.end(), GV);
113 if (I == Globals.end() || *I != GV) {
114 //assert(GV->getType()->getElementType() == Ty);
115 Globals.insert(I, GV);
116 NodeType |= GlobalNode;
120 /// foldNodeCompletely - If we determine that this node has some funny
121 /// behavior happening to it that we cannot represent, we fold it down to a
122 /// single, completely pessimistic, node. This node is represented as a
123 /// single byte with a single TypeEntry of "void".
125 void DSNode::foldNodeCompletely() {
126 if (isNodeCompletelyFolded()) return; // If this node is already folded...
130 // Create the node we are going to forward to...
131 DSNode *DestNode = new DSNode(0, ParentGraph);
132 DestNode->NodeType = NodeType|DSNode::Array;
133 DestNode->Ty = Type::VoidTy;
135 DestNode->Globals.swap(Globals);
137 // Start forwarding to the destination node...
138 forwardNode(DestNode, 0);
141 DestNode->Links.push_back(Links[0]);
142 DSNodeHandle NH(DestNode);
144 // If we have links, merge all of our outgoing links together...
145 for (unsigned i = Links.size()-1; i != 0; --i)
146 NH.getNode()->Links[0].mergeWith(Links[i]);
149 DestNode->Links.resize(1);
153 /// isNodeCompletelyFolded - Return true if this node has been completely
154 /// folded down to something that can never be expanded, effectively losing
155 /// all of the field sensitivity that may be present in the node.
157 bool DSNode::isNodeCompletelyFolded() const {
158 return getSize() == 1 && Ty == Type::VoidTy && isArray();
163 /// TypeElementWalker Class - Used for implementation of physical subtyping...
165 class TypeElementWalker {
170 StackState(const Type *T, unsigned Off = 0)
171 : Ty(T), Offset(Off), Idx(0) {}
174 std::vector<StackState> Stack;
176 TypeElementWalker(const Type *T) {
181 bool isDone() const { return Stack.empty(); }
182 const Type *getCurrentType() const { return Stack.back().Ty; }
183 unsigned getCurrentOffset() const { return Stack.back().Offset; }
185 void StepToNextType() {
186 PopStackAndAdvance();
191 /// PopStackAndAdvance - Pop the current element off of the stack and
192 /// advance the underlying element to the next contained member.
193 void PopStackAndAdvance() {
194 assert(!Stack.empty() && "Cannot pop an empty stack!");
196 while (!Stack.empty()) {
197 StackState &SS = Stack.back();
198 if (const StructType *ST = dyn_cast<StructType>(SS.Ty)) {
200 if (SS.Idx != ST->getElementTypes().size()) {
201 const StructLayout *SL = TD.getStructLayout(ST);
202 SS.Offset += SL->MemberOffsets[SS.Idx]-SL->MemberOffsets[SS.Idx-1];
205 Stack.pop_back(); // At the end of the structure
207 const ArrayType *AT = cast<ArrayType>(SS.Ty);
209 if (SS.Idx != AT->getNumElements()) {
210 SS.Offset += TD.getTypeSize(AT->getElementType());
213 Stack.pop_back(); // At the end of the array
218 /// StepToLeaf - Used by physical subtyping to move to the first leaf node
219 /// on the type stack.
221 if (Stack.empty()) return;
222 while (!Stack.empty() && !Stack.back().Ty->isFirstClassType()) {
223 StackState &SS = Stack.back();
224 if (const StructType *ST = dyn_cast<StructType>(SS.Ty)) {
225 if (ST->getElementTypes().empty()) {
227 PopStackAndAdvance();
229 // Step into the structure...
230 assert(SS.Idx < ST->getElementTypes().size());
231 const StructLayout *SL = TD.getStructLayout(ST);
232 Stack.push_back(StackState(ST->getElementTypes()[SS.Idx],
233 SS.Offset+SL->MemberOffsets[SS.Idx]));
236 const ArrayType *AT = cast<ArrayType>(SS.Ty);
237 if (AT->getNumElements() == 0) {
239 PopStackAndAdvance();
241 // Step into the array...
242 assert(SS.Idx < AT->getNumElements());
243 Stack.push_back(StackState(AT->getElementType(),
245 TD.getTypeSize(AT->getElementType())));
253 /// ElementTypesAreCompatible - Check to see if the specified types are
254 /// "physically" compatible. If so, return true, else return false. We only
255 /// have to check the fields in T1: T2 may be larger than T1.
257 static bool ElementTypesAreCompatible(const Type *T1, const Type *T2) {
258 TypeElementWalker T1W(T1), T2W(T2);
260 while (!T1W.isDone() && !T2W.isDone()) {
261 if (T1W.getCurrentOffset() != T2W.getCurrentOffset())
264 const Type *T1 = T1W.getCurrentType();
265 const Type *T2 = T2W.getCurrentType();
266 if (T1 != T2 && !T1->isLosslesslyConvertibleTo(T2))
269 T1W.StepToNextType();
270 T2W.StepToNextType();
277 /// mergeTypeInfo - This method merges the specified type into the current node
278 /// at the specified offset. This may update the current node's type record if
279 /// this gives more information to the node, it may do nothing to the node if
280 /// this information is already known, or it may merge the node completely (and
281 /// return true) if the information is incompatible with what is already known.
283 /// This method returns true if the node is completely folded, otherwise false.
285 bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset,
286 bool FoldIfIncompatible) {
287 // Check to make sure the Size member is up-to-date. Size can be one of the
289 // Size = 0, Ty = Void: Nothing is known about this node.
290 // Size = 0, Ty = FnTy: FunctionPtr doesn't have a size, so we use zero
291 // Size = 1, Ty = Void, Array = 1: The node is collapsed
292 // Otherwise, sizeof(Ty) = Size
294 assert(((Size == 0 && Ty == Type::VoidTy && !isArray()) ||
295 (Size == 0 && !Ty->isSized() && !isArray()) ||
296 (Size == 1 && Ty == Type::VoidTy && isArray()) ||
297 (Size == 0 && !Ty->isSized() && !isArray()) ||
298 (TD.getTypeSize(Ty) == Size)) &&
299 "Size member of DSNode doesn't match the type structure!");
300 assert(NewTy != Type::VoidTy && "Cannot merge void type into DSNode!");
302 if (Offset == 0 && NewTy == Ty)
303 return false; // This should be a common case, handle it efficiently
305 // Return true immediately if the node is completely folded.
306 if (isNodeCompletelyFolded()) return true;
308 // If this is an array type, eliminate the outside arrays because they won't
309 // be used anyway. This greatly reduces the size of large static arrays used
310 // as global variables, for example.
312 bool WillBeArray = false;
313 while (const ArrayType *AT = dyn_cast<ArrayType>(NewTy)) {
314 // FIXME: we might want to keep small arrays, but must be careful about
315 // things like: [2 x [10000 x int*]]
316 NewTy = AT->getElementType();
320 // Figure out how big the new type we're merging in is...
321 unsigned NewTySize = NewTy->isSized() ? TD.getTypeSize(NewTy) : 0;
323 // Otherwise check to see if we can fold this type into the current node. If
324 // we can't, we fold the node completely, if we can, we potentially update our
327 if (Ty == Type::VoidTy) {
328 // If this is the first type that this node has seen, just accept it without
330 assert(Offset == 0 && "Cannot have an offset into a void node!");
331 assert(!isArray() && "This shouldn't happen!");
334 if (WillBeArray) NodeType |= Array;
337 // Calculate the number of outgoing links from this node.
338 Links.resize((Size+DS::PointerSize-1) >> DS::PointerShift);
342 // Handle node expansion case here...
343 if (Offset+NewTySize > Size) {
344 // It is illegal to grow this node if we have treated it as an array of
347 if (FoldIfIncompatible) foldNodeCompletely();
351 if (Offset) { // We could handle this case, but we don't for now...
352 std::cerr << "UNIMP: Trying to merge a growth type into "
353 << "offset != 0: Collapsing!\n";
354 if (FoldIfIncompatible) foldNodeCompletely();
358 // Okay, the situation is nice and simple, we are trying to merge a type in
359 // at offset 0 that is bigger than our current type. Implement this by
360 // switching to the new type and then merge in the smaller one, which should
361 // hit the other code path here. If the other code path decides it's not
362 // ok, it will collapse the node as appropriate.
364 const Type *OldTy = Ty;
367 if (WillBeArray) NodeType |= Array;
370 // Must grow links to be the appropriate size...
371 Links.resize((Size+DS::PointerSize-1) >> DS::PointerShift);
373 // Merge in the old type now... which is guaranteed to be smaller than the
375 return mergeTypeInfo(OldTy, 0);
378 assert(Offset <= Size &&
379 "Cannot merge something into a part of our type that doesn't exist!");
381 // Find the section of Ty that NewTy overlaps with... first we find the
382 // type that starts at offset Offset.
385 const Type *SubType = Ty;
387 assert(Offset-O < TD.getTypeSize(SubType) && "Offset out of range!");
389 switch (SubType->getPrimitiveID()) {
390 case Type::StructTyID: {
391 const StructType *STy = cast<StructType>(SubType);
392 const StructLayout &SL = *TD.getStructLayout(STy);
394 unsigned i = 0, e = SL.MemberOffsets.size();
395 for (; i+1 < e && SL.MemberOffsets[i+1] <= Offset-O; ++i)
398 // The offset we are looking for must be in the i'th element...
399 SubType = STy->getElementTypes()[i];
400 O += SL.MemberOffsets[i];
403 case Type::ArrayTyID: {
404 SubType = cast<ArrayType>(SubType)->getElementType();
405 unsigned ElSize = TD.getTypeSize(SubType);
406 unsigned Remainder = (Offset-O) % ElSize;
407 O = Offset-Remainder;
411 if (FoldIfIncompatible) foldNodeCompletely();
416 assert(O == Offset && "Could not achieve the correct offset!");
418 // If we found our type exactly, early exit
419 if (SubType == NewTy) return false;
421 unsigned SubTypeSize = SubType->isSized() ? TD.getTypeSize(SubType) : 0;
423 // Ok, we are getting desperate now. Check for physical subtyping, where we
424 // just require each element in the node to be compatible.
425 if (NewTySize <= SubTypeSize && NewTySize && NewTySize < 256 &&
426 SubTypeSize && SubTypeSize < 256 &&
427 ElementTypesAreCompatible(NewTy, SubType))
430 // Okay, so we found the leader type at the offset requested. Search the list
431 // of types that starts at this offset. If SubType is currently an array or
432 // structure, the type desired may actually be the first element of the
435 unsigned PadSize = SubTypeSize; // Size, including pad memory which is ignored
436 while (SubType != NewTy) {
437 const Type *NextSubType = 0;
438 unsigned NextSubTypeSize = 0;
439 unsigned NextPadSize = 0;
440 switch (SubType->getPrimitiveID()) {
441 case Type::StructTyID: {
442 const StructType *STy = cast<StructType>(SubType);
443 const StructLayout &SL = *TD.getStructLayout(STy);
444 if (SL.MemberOffsets.size() > 1)
445 NextPadSize = SL.MemberOffsets[1];
447 NextPadSize = SubTypeSize;
448 NextSubType = STy->getElementTypes()[0];
449 NextSubTypeSize = TD.getTypeSize(NextSubType);
452 case Type::ArrayTyID:
453 NextSubType = cast<ArrayType>(SubType)->getElementType();
454 NextSubTypeSize = TD.getTypeSize(NextSubType);
455 NextPadSize = NextSubTypeSize;
461 if (NextSubType == 0)
462 break; // In the default case, break out of the loop
464 if (NextPadSize < NewTySize)
465 break; // Don't allow shrinking to a smaller type than NewTySize
466 SubType = NextSubType;
467 SubTypeSize = NextSubTypeSize;
468 PadSize = NextPadSize;
471 // If we found the type exactly, return it...
472 if (SubType == NewTy)
475 // Check to see if we have a compatible, but different type...
476 if (NewTySize == SubTypeSize) {
477 // Check to see if this type is obviously convertible... int -> uint f.e.
478 if (NewTy->isLosslesslyConvertibleTo(SubType))
481 // Check to see if we have a pointer & integer mismatch going on here,
482 // loading a pointer as a long, for example.
484 if (SubType->isInteger() && isa<PointerType>(NewTy) ||
485 NewTy->isInteger() && isa<PointerType>(SubType))
487 } else if (NewTySize > SubTypeSize && NewTySize <= PadSize) {
488 // We are accessing the field, plus some structure padding. Ignore the
489 // structure padding.
494 if (getParentGraph()->getReturnNodes().size())
495 M = getParentGraph()->getReturnNodes().begin()->first->getParent();
496 DEBUG(std::cerr << "MergeTypeInfo Folding OrigTy: ";
497 WriteTypeSymbolic(std::cerr, Ty, M) << "\n due to:";
498 WriteTypeSymbolic(std::cerr, NewTy, M) << " @ " << Offset << "!\n"
500 WriteTypeSymbolic(std::cerr, SubType, M) << "\n\n");
502 if (FoldIfIncompatible) foldNodeCompletely();
508 // addEdgeTo - Add an edge from the current node to the specified node. This
509 // can cause merging of nodes in the graph.
511 void DSNode::addEdgeTo(unsigned Offset, const DSNodeHandle &NH) {
512 if (NH.getNode() == 0) return; // Nothing to do
514 DSNodeHandle &ExistingEdge = getLink(Offset);
515 if (ExistingEdge.getNode()) {
516 // Merge the two nodes...
517 ExistingEdge.mergeWith(NH);
518 } else { // No merging to perform...
519 setLink(Offset, NH); // Just force a link in there...
524 // MergeSortedVectors - Efficiently merge a vector into another vector where
525 // duplicates are not allowed and both are sorted. This assumes that 'T's are
526 // efficiently copyable and have sane comparison semantics.
528 static void MergeSortedVectors(std::vector<GlobalValue*> &Dest,
529 const std::vector<GlobalValue*> &Src) {
530 // By far, the most common cases will be the simple ones. In these cases,
531 // avoid having to allocate a temporary vector...
533 if (Src.empty()) { // Nothing to merge in...
535 } else if (Dest.empty()) { // Just copy the result in...
537 } else if (Src.size() == 1) { // Insert a single element...
538 const GlobalValue *V = Src[0];
539 std::vector<GlobalValue*>::iterator I =
540 std::lower_bound(Dest.begin(), Dest.end(), V);
541 if (I == Dest.end() || *I != Src[0]) // If not already contained...
542 Dest.insert(I, Src[0]);
543 } else if (Dest.size() == 1) {
544 GlobalValue *Tmp = Dest[0]; // Save value in temporary...
545 Dest = Src; // Copy over list...
546 std::vector<GlobalValue*>::iterator I =
547 std::lower_bound(Dest.begin(), Dest.end(), Tmp);
548 if (I == Dest.end() || *I != Tmp) // If not already contained...
552 // Make a copy to the side of Dest...
553 std::vector<GlobalValue*> Old(Dest);
555 // Make space for all of the type entries now...
556 Dest.resize(Dest.size()+Src.size());
558 // Merge the two sorted ranges together... into Dest.
559 std::merge(Old.begin(), Old.end(), Src.begin(), Src.end(), Dest.begin());
561 // Now erase any duplicate entries that may have accumulated into the
562 // vectors (because they were in both of the input sets)
563 Dest.erase(std::unique(Dest.begin(), Dest.end()), Dest.end());
568 // MergeNodes() - Helper function for DSNode::mergeWith().
569 // This function does the hard work of merging two nodes, CurNodeH
570 // and NH after filtering out trivial cases and making sure that
571 // CurNodeH.offset >= NH.offset.
574 // Since merging may cause either node to go away, we must always
575 // use the node-handles to refer to the nodes. These node handles are
576 // automatically updated during merging, so will always provide access
577 // to the correct node after a merge.
579 void DSNode::MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH) {
580 assert(CurNodeH.getOffset() >= NH.getOffset() &&
581 "This should have been enforced in the caller.");
583 // Now we know that Offset >= NH.Offset, so convert it so our "Offset" (with
584 // respect to NH.Offset) is now zero. NOffset is the distance from the base
585 // of our object that N starts from.
587 unsigned NOffset = CurNodeH.getOffset()-NH.getOffset();
588 unsigned NSize = NH.getNode()->getSize();
590 // If the two nodes are of different size, and the smaller node has the array
591 // bit set, collapse!
592 if (NSize != CurNodeH.getNode()->getSize()) {
593 if (NSize < CurNodeH.getNode()->getSize()) {
594 if (NH.getNode()->isArray())
595 NH.getNode()->foldNodeCompletely();
596 } else if (CurNodeH.getNode()->isArray()) {
597 NH.getNode()->foldNodeCompletely();
601 // Merge the type entries of the two nodes together...
602 if (NH.getNode()->Ty != Type::VoidTy)
603 CurNodeH.getNode()->mergeTypeInfo(NH.getNode()->Ty, NOffset);
604 assert(!CurNodeH.getNode()->isDeadNode());
606 // If we are merging a node with a completely folded node, then both nodes are
607 // now completely folded.
609 if (CurNodeH.getNode()->isNodeCompletelyFolded()) {
610 if (!NH.getNode()->isNodeCompletelyFolded()) {
611 NH.getNode()->foldNodeCompletely();
612 assert(NH.getNode() && NH.getOffset() == 0 &&
613 "folding did not make offset 0?");
614 NOffset = NH.getOffset();
615 NSize = NH.getNode()->getSize();
616 assert(NOffset == 0 && NSize == 1);
618 } else if (NH.getNode()->isNodeCompletelyFolded()) {
619 CurNodeH.getNode()->foldNodeCompletely();
620 assert(CurNodeH.getNode() && CurNodeH.getOffset() == 0 &&
621 "folding did not make offset 0?");
622 NOffset = NH.getOffset();
623 NSize = NH.getNode()->getSize();
624 assert(NOffset == 0 && NSize == 1);
627 DSNode *N = NH.getNode();
628 if (CurNodeH.getNode() == N || N == 0) return;
629 assert(!CurNodeH.getNode()->isDeadNode());
631 // Merge the NodeType information...
632 CurNodeH.getNode()->NodeType |= N->NodeType;
634 // Start forwarding to the new node!
635 N->forwardNode(CurNodeH.getNode(), NOffset);
636 assert(!CurNodeH.getNode()->isDeadNode());
638 // Make all of the outgoing links of N now be outgoing links of CurNodeH.
640 for (unsigned i = 0; i < N->getNumLinks(); ++i) {
641 DSNodeHandle &Link = N->getLink(i << DS::PointerShift);
642 if (Link.getNode()) {
643 // Compute the offset into the current node at which to
644 // merge this link. In the common case, this is a linear
645 // relation to the offset in the original node (with
646 // wrapping), but if the current node gets collapsed due to
647 // recursive merging, we must make sure to merge in all remaining
648 // links at offset zero.
649 unsigned MergeOffset = 0;
650 DSNode *CN = CurNodeH.getNode();
652 MergeOffset = ((i << DS::PointerShift)+NOffset) % CN->getSize();
653 CN->addEdgeTo(MergeOffset, Link);
657 // Now that there are no outgoing edges, all of the Links are dead.
660 // Merge the globals list...
661 if (!N->Globals.empty()) {
662 MergeSortedVectors(CurNodeH.getNode()->Globals, N->Globals);
664 // Delete the globals from the old node...
665 std::vector<GlobalValue*>().swap(N->Globals);
670 // mergeWith - Merge this node and the specified node, moving all links to and
671 // from the argument node into the current node, deleting the node argument.
672 // Offset indicates what offset the specified node is to be merged into the
675 // The specified node may be a null pointer (in which case, nothing happens).
677 void DSNode::mergeWith(const DSNodeHandle &NH, unsigned Offset) {
678 DSNode *N = NH.getNode();
679 if (N == 0 || (N == this && NH.getOffset() == Offset))
682 assert(!N->isDeadNode() && !isDeadNode());
683 assert(!hasNoReferrers() && "Should not try to fold a useless node!");
686 // We cannot merge two pieces of the same node together, collapse the node
688 DEBUG(std::cerr << "Attempting to merge two chunks of"
689 << " the same node together!\n");
690 foldNodeCompletely();
694 // If both nodes are not at offset 0, make sure that we are merging the node
695 // at an later offset into the node with the zero offset.
697 if (Offset < NH.getOffset()) {
698 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
700 } else if (Offset == NH.getOffset() && getSize() < N->getSize()) {
701 // If the offsets are the same, merge the smaller node into the bigger node
702 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
706 // Ok, now we can merge the two nodes. Use a static helper that works with
707 // two node handles, since "this" may get merged away at intermediate steps.
708 DSNodeHandle CurNodeH(this, Offset);
709 DSNodeHandle NHCopy(NH);
710 DSNode::MergeNodes(CurNodeH, NHCopy);
713 //===----------------------------------------------------------------------===//
714 // DSCallSite Implementation
715 //===----------------------------------------------------------------------===//
717 // Define here to avoid including iOther.h and BasicBlock.h in DSGraph.h
718 Function &DSCallSite::getCaller() const {
719 return *Site.getInstruction()->getParent()->getParent();
723 //===----------------------------------------------------------------------===//
724 // DSGraph Implementation
725 //===----------------------------------------------------------------------===//
727 /// getFunctionNames - Return a space separated list of the name of the
728 /// functions in this graph (if any)
729 std::string DSGraph::getFunctionNames() const {
730 switch (getReturnNodes().size()) {
731 case 0: return "Globals graph";
732 case 1: return getReturnNodes().begin()->first->getName();
735 for (DSGraph::ReturnNodesTy::const_iterator I = getReturnNodes().begin();
736 I != getReturnNodes().end(); ++I)
737 Return += I->first->getName() + " ";
738 Return.erase(Return.end()-1, Return.end()); // Remove last space character
744 DSGraph::DSGraph(const DSGraph &G) : GlobalsGraph(0) {
745 PrintAuxCalls = false;
747 cloneInto(G, ScalarMap, ReturnNodes, NodeMap);
748 InlinedGlobals.clear(); // clear set of "up-to-date" globals
751 DSGraph::DSGraph(const DSGraph &G, NodeMapTy &NodeMap)
753 PrintAuxCalls = false;
754 cloneInto(G, ScalarMap, ReturnNodes, NodeMap);
755 InlinedGlobals.clear(); // clear set of "up-to-date" globals
758 DSGraph::~DSGraph() {
759 FunctionCalls.clear();
760 AuxFunctionCalls.clear();
761 InlinedGlobals.clear();
765 // Drop all intra-node references, so that assertions don't fail...
766 std::for_each(Nodes.begin(), Nodes.end(),
767 std::mem_fun(&DSNode::dropAllReferences));
769 // Delete all of the nodes themselves...
770 std::for_each(Nodes.begin(), Nodes.end(), deleter<DSNode>);
773 // dump - Allow inspection of graph in a debugger.
774 void DSGraph::dump() const { print(std::cerr); }
777 /// remapLinks - Change all of the Links in the current node according to the
778 /// specified mapping.
780 void DSNode::remapLinks(DSGraph::NodeMapTy &OldNodeMap) {
781 for (unsigned i = 0, e = Links.size(); i != e; ++i) {
782 DSNodeHandle &H = OldNodeMap[Links[i].getNode()];
783 Links[i].setNode(H.getNode());
784 Links[i].setOffset(Links[i].getOffset()+H.getOffset());
789 /// cloneReachableNodes - Clone all reachable nodes from *Node into the
790 /// current graph. This is a recursive function. The map OldNodeMap is a
791 /// map from the original nodes to their clones.
793 void DSGraph::cloneReachableNodes(const DSNode* Node,
794 unsigned BitsToClear,
795 NodeMapTy& OldNodeMap,
796 NodeMapTy& CompletedNodeMap) {
797 if (CompletedNodeMap.find(Node) != CompletedNodeMap.end())
800 DSNodeHandle& NH = OldNodeMap[Node];
801 if (NH.getNode() != NULL)
804 // else Node has not yet been cloned: clone it and clear the specified bits
805 NH = new DSNode(*Node, this); // enters in OldNodeMap
806 NH.getNode()->maskNodeTypes(~BitsToClear);
808 // now recursively clone nodes pointed to by this node
809 for (unsigned i = 0, e = Node->getNumLinks(); i != e; ++i) {
810 const DSNodeHandle &Link = Node->getLink(i << DS::PointerShift);
811 if (const DSNode* nextNode = Link.getNode())
812 cloneReachableNodes(nextNode, BitsToClear, OldNodeMap, CompletedNodeMap);
816 void DSGraph::cloneReachableSubgraph(const DSGraph& G,
817 const hash_set<const DSNode*>& RootNodes,
818 NodeMapTy& OldNodeMap,
819 NodeMapTy& CompletedNodeMap,
820 unsigned CloneFlags) {
821 if (RootNodes.empty())
824 assert(OldNodeMap.empty() && "Returned OldNodeMap should be empty!");
825 assert(&G != this && "Cannot clone graph into itself!");
826 assert((*RootNodes.begin())->getParentGraph() == &G &&
827 "Root nodes do not belong to this graph!");
829 // Remove alloca or mod/ref bits as specified...
830 unsigned BitsToClear = ((CloneFlags & StripAllocaBit)? DSNode::AllocaNode : 0)
831 | ((CloneFlags & StripModRefBits)? (DSNode::Modified | DSNode::Read) : 0)
832 | ((CloneFlags & StripIncompleteBit)? DSNode::Incomplete : 0);
833 BitsToClear |= DSNode::DEAD; // Clear dead flag...
835 // Clone all nodes reachable from each root node, using a recursive helper
836 for (hash_set<const DSNode*>::const_iterator I = RootNodes.begin(),
837 E = RootNodes.end(); I != E; ++I)
838 cloneReachableNodes(*I, BitsToClear, OldNodeMap, CompletedNodeMap);
840 // Merge the map entries in OldNodeMap and CompletedNodeMap to remap links
841 NodeMapTy MergedMap(OldNodeMap);
842 MergedMap.insert(CompletedNodeMap.begin(), CompletedNodeMap.end());
844 // Rewrite the links in the newly created nodes (the nodes in OldNodeMap)
845 // to point into the current graph. MergedMap gives the full mapping.
846 for (NodeMapTy::iterator I=OldNodeMap.begin(), E=OldNodeMap.end(); I!= E; ++I)
847 I->second.getNode()->remapLinks(MergedMap);
849 // Now merge cloned global nodes with their copies in the current graph
850 // Just look through OldNodeMap to find such nodes!
851 for (NodeMapTy::iterator I=OldNodeMap.begin(), E=OldNodeMap.end(); I!= E; ++I)
852 if (I->first->isGlobalNode()) {
853 DSNodeHandle &GClone = I->second;
854 assert(GClone.getNode() != NULL && "NULL node in OldNodeMap?");
855 const std::vector<GlobalValue*> &Globals = I->first->getGlobals();
856 for (unsigned gi = 0, ge = Globals.size(); gi != ge; ++gi) {
857 DSNodeHandle &GH = ScalarMap[Globals[gi]];
858 GH.mergeWith(GClone);
864 /// updateFromGlobalGraph - This function rematerializes global nodes and
865 /// nodes reachable from them from the globals graph into the current graph.
866 /// It invokes cloneReachableSubgraph, using the globals in the current graph
867 /// as the roots. It also uses the vector InlinedGlobals to avoid cloning and
868 /// merging globals that are already up-to-date in the current graph. In
869 /// practice, in the TD pass, this is likely to be a large fraction of the
870 /// live global nodes in each function (since most live nodes are likely to
871 /// have been brought up-to-date in at _some_ caller or callee).
873 void DSGraph::updateFromGlobalGraph() {
875 // Use a map to keep track of the mapping between nodes in the globals graph
876 // and this graph for up-to-date global nodes, which do not need to be cloned.
877 NodeMapTy CompletedMap;
879 // Put the live, non-up-to-date global nodes into a set and the up-to-date
880 // ones in the map above, mapping node in GlobalsGraph to the up-to-date node.
881 hash_set<const DSNode*> GlobalNodeSet;
882 for (ScalarMapTy::const_iterator I = getScalarMap().begin(),
883 E = getScalarMap().end(); I != E; ++I)
884 if (GlobalValue* GV = dyn_cast<GlobalValue>(I->first)) {
885 DSNode* GNode = I->second.getNode();
886 assert(GNode && "No node for live global in current Graph?");
887 if (const DSNode* GGNode = GlobalsGraph->ScalarMap[GV].getNode())
888 if (InlinedGlobals.count(GV) == 0) // GNode is not up-to-date
889 GlobalNodeSet.insert(GGNode);
890 else { // GNode is up-to-date
891 CompletedMap[GGNode] = I->second;
892 assert(GGNode->getNumLinks() == GNode->getNumLinks() &&
893 "Links dont match in a node that is supposed to be up-to-date?"
894 "\nremapLinks() will not work if the links don't match!");
898 // Clone the subgraph reachable from the vector of nodes in GlobalNodes
899 // and merge the cloned global nodes with the corresponding ones, if any.
900 NodeMapTy OldNodeMap;
901 cloneReachableSubgraph(*GlobalsGraph, GlobalNodeSet, OldNodeMap,CompletedMap);
903 // Merging global nodes leaves behind unused nodes: get rid of them now.
904 OldNodeMap.clear(); // remove references before dead node cleanup
905 CompletedMap.clear(); // remove references before dead node cleanup
906 removeTriviallyDeadNodes();
909 /// cloneInto - Clone the specified DSGraph into the current graph. The
910 /// translated ScalarMap for the old function is filled into the OldValMap
911 /// member, and the translated ReturnNodes map is returned into ReturnNodes.
913 /// The CloneFlags member controls various aspects of the cloning process.
915 void DSGraph::cloneInto(const DSGraph &G, ScalarMapTy &OldValMap,
916 ReturnNodesTy &OldReturnNodes, NodeMapTy &OldNodeMap,
917 unsigned CloneFlags) {
918 assert(OldNodeMap.empty() && "Returned OldNodeMap should be empty!");
919 assert(&G != this && "Cannot clone graph into itself!");
921 unsigned FN = Nodes.size(); // First new node...
923 // Duplicate all of the nodes, populating the node map...
924 Nodes.reserve(FN+G.Nodes.size());
926 // Remove alloca or mod/ref bits as specified...
927 unsigned BitsToClear = ((CloneFlags & StripAllocaBit)? DSNode::AllocaNode : 0)
928 | ((CloneFlags & StripModRefBits)? (DSNode::Modified | DSNode::Read) : 0)
929 | ((CloneFlags & StripIncompleteBit)? DSNode::Incomplete : 0);
930 BitsToClear |= DSNode::DEAD; // Clear dead flag...
931 for (unsigned i = 0, e = G.Nodes.size(); i != e; ++i) {
932 DSNode *Old = G.Nodes[i];
933 DSNode *New = new DSNode(*Old, this);
934 New->maskNodeTypes(~BitsToClear);
935 OldNodeMap[Old] = New;
939 Timer::addPeakMemoryMeasurement();
942 // Rewrite the links in the new nodes to point into the current graph now.
943 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
944 Nodes[i]->remapLinks(OldNodeMap);
946 // Copy the scalar map... merging all of the global nodes...
947 for (ScalarMapTy::const_iterator I = G.ScalarMap.begin(),
948 E = G.ScalarMap.end(); I != E; ++I) {
949 DSNodeHandle &MappedNode = OldNodeMap[I->second.getNode()];
950 DSNodeHandle &H = OldValMap[I->first];
951 H.mergeWith(DSNodeHandle(MappedNode.getNode(),
952 I->second.getOffset()+MappedNode.getOffset()));
954 // If this is a global, add the global to this fn or merge if already exists
955 if (GlobalValue* GV = dyn_cast<GlobalValue>(I->first)) {
956 ScalarMap[GV].mergeWith(H);
957 InlinedGlobals.insert(GV);
961 if (!(CloneFlags & DontCloneCallNodes)) {
962 // Copy the function calls list...
963 unsigned FC = FunctionCalls.size(); // FirstCall
964 FunctionCalls.reserve(FC+G.FunctionCalls.size());
965 for (unsigned i = 0, ei = G.FunctionCalls.size(); i != ei; ++i)
966 FunctionCalls.push_back(DSCallSite(G.FunctionCalls[i], OldNodeMap));
969 if (!(CloneFlags & DontCloneAuxCallNodes)) {
970 // Copy the auxiliary function calls list...
971 unsigned FC = AuxFunctionCalls.size(); // FirstCall
972 AuxFunctionCalls.reserve(FC+G.AuxFunctionCalls.size());
973 for (unsigned i = 0, ei = G.AuxFunctionCalls.size(); i != ei; ++i)
974 AuxFunctionCalls.push_back(DSCallSite(G.AuxFunctionCalls[i], OldNodeMap));
977 // Map the return node pointers over...
978 for (ReturnNodesTy::const_iterator I = G.getReturnNodes().begin(),
979 E = G.getReturnNodes().end(); I != E; ++I) {
980 const DSNodeHandle &Ret = I->second;
981 DSNodeHandle &MappedRet = OldNodeMap[Ret.getNode()];
982 OldReturnNodes.insert(std::make_pair(I->first,
983 DSNodeHandle(MappedRet.getNode(),
984 MappedRet.getOffset()+Ret.getOffset())));
988 /// mergeInGraph - The method is used for merging graphs together. If the
989 /// argument graph is not *this, it makes a clone of the specified graph, then
990 /// merges the nodes specified in the call site with the formal arguments in the
993 void DSGraph::mergeInGraph(const DSCallSite &CS, Function &F,
994 const DSGraph &Graph, unsigned CloneFlags) {
995 ScalarMapTy OldValMap, *ScalarMap;
998 // If this is not a recursive call, clone the graph into this graph...
999 if (&Graph != this) {
1000 // Clone the callee's graph into the current graph, keeping
1001 // track of where scalars in the old graph _used_ to point,
1002 // and of the new nodes matching nodes of the old graph.
1003 NodeMapTy OldNodeMap;
1005 // The clone call may invalidate any of the vectors in the data
1006 // structure graph. Strip locals and don't copy the list of callers
1007 ReturnNodesTy OldRetNodes;
1008 cloneInto(Graph, OldValMap, OldRetNodes, OldNodeMap, CloneFlags);
1010 // We need to map the arguments for the function to the cloned nodes old
1011 // argument values. Do this now.
1012 RetVal = OldRetNodes[&F];
1013 ScalarMap = &OldValMap;
1015 RetVal = getReturnNodeFor(F);
1016 ScalarMap = &getScalarMap();
1019 // Merge the return value with the return value of the context...
1020 RetVal.mergeWith(CS.getRetVal());
1022 // Resolve all of the function arguments...
1023 Function::aiterator AI = F.abegin();
1025 for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i, ++AI) {
1026 // Advance the argument iterator to the first pointer argument...
1027 while (AI != F.aend() && !isPointerType(AI->getType())) {
1031 std::cerr << "Bad call to Function: " << F.getName() << "\n";
1034 if (AI == F.aend()) break;
1036 // Add the link from the argument scalar to the provided value
1037 assert(ScalarMap->count(AI) && "Argument not in scalar map?");
1038 DSNodeHandle &NH = (*ScalarMap)[AI];
1039 assert(NH.getNode() && "Pointer argument without scalarmap entry?");
1040 NH.mergeWith(CS.getPtrArg(i));
1044 /// getCallSiteForArguments - Get the arguments and return value bindings for
1045 /// the specified function in the current graph.
1047 DSCallSite DSGraph::getCallSiteForArguments(Function &F) const {
1048 std::vector<DSNodeHandle> Args;
1050 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I)
1051 if (isPointerType(I->getType()))
1052 Args.push_back(getScalarMap().find(I)->second);
1054 return DSCallSite(CallSite(), getReturnNodeFor(F), &F, Args);
1059 // markIncompleteNodes - Mark the specified node as having contents that are not
1060 // known with the current analysis we have performed. Because a node makes all
1061 // of the nodes it can reach incomplete if the node itself is incomplete, we
1062 // must recursively traverse the data structure graph, marking all reachable
1063 // nodes as incomplete.
1065 static void markIncompleteNode(DSNode *N) {
1066 // Stop recursion if no node, or if node already marked...
1067 if (N == 0 || N->isIncomplete()) return;
1069 // Actually mark the node
1070 N->setIncompleteMarker();
1072 // Recursively process children...
1073 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
1074 if (DSNode *DSN = N->getLink(i).getNode())
1075 markIncompleteNode(DSN);
1078 static void markIncomplete(DSCallSite &Call) {
1079 // Then the return value is certainly incomplete!
1080 markIncompleteNode(Call.getRetVal().getNode());
1082 // All objects pointed to by function arguments are incomplete!
1083 for (unsigned i = 0, e = Call.getNumPtrArgs(); i != e; ++i)
1084 markIncompleteNode(Call.getPtrArg(i).getNode());
1087 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
1088 // modified by other functions that have not been resolved yet. This marks
1089 // nodes that are reachable through three sources of "unknownness":
1091 // Global Variables, Function Calls, and Incoming Arguments
1093 // For any node that may have unknown components (because something outside the
1094 // scope of current analysis may have modified it), the 'Incomplete' flag is
1095 // added to the NodeType.
1097 void DSGraph::markIncompleteNodes(unsigned Flags) {
1098 // Mark any incoming arguments as incomplete...
1099 if (Flags & DSGraph::MarkFormalArgs)
1100 for (ReturnNodesTy::iterator FI = ReturnNodes.begin(), E =ReturnNodes.end();
1102 Function &F = *FI->first;
1103 if (F.getName() != "main")
1104 for (Function::aiterator I = F.abegin(), E = F.aend(); I != E; ++I)
1105 if (isPointerType(I->getType()) &&
1106 ScalarMap.find(I) != ScalarMap.end())
1107 markIncompleteNode(ScalarMap[I].getNode());
1110 // Mark stuff passed into functions calls as being incomplete...
1111 if (!shouldPrintAuxCalls())
1112 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
1113 markIncomplete(FunctionCalls[i]);
1115 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
1116 markIncomplete(AuxFunctionCalls[i]);
1119 // Mark all global nodes as incomplete...
1120 if ((Flags & DSGraph::IgnoreGlobals) == 0)
1121 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
1122 if (Nodes[i]->isGlobalNode() && Nodes[i]->getNumLinks())
1123 markIncompleteNode(Nodes[i]);
1126 static inline void killIfUselessEdge(DSNodeHandle &Edge) {
1127 if (DSNode *N = Edge.getNode()) // Is there an edge?
1128 if (N->getNumReferrers() == 1) // Does it point to a lonely node?
1129 // No interesting info?
1130 if ((N->getNodeFlags() & ~DSNode::Incomplete) == 0 &&
1131 N->getType() == Type::VoidTy && !N->isNodeCompletelyFolded())
1132 Edge.setNode(0); // Kill the edge!
1135 static inline bool nodeContainsExternalFunction(const DSNode *N) {
1136 const std::vector<GlobalValue*> &Globals = N->getGlobals();
1137 for (unsigned i = 0, e = Globals.size(); i != e; ++i)
1138 if (Globals[i]->isExternal())
1143 static void removeIdenticalCalls(std::vector<DSCallSite> &Calls) {
1145 // Remove trivially identical function calls
1146 unsigned NumFns = Calls.size();
1147 std::sort(Calls.begin(), Calls.end()); // Sort by callee as primary key!
1149 // Scan the call list cleaning it up as necessary...
1150 DSNode *LastCalleeNode = 0;
1151 Function *LastCalleeFunc = 0;
1152 unsigned NumDuplicateCalls = 0;
1153 bool LastCalleeContainsExternalFunction = false;
1154 for (unsigned i = 0; i != Calls.size(); ++i) {
1155 DSCallSite &CS = Calls[i];
1157 // If the Callee is a useless edge, this must be an unreachable call site,
1159 if (CS.isIndirectCall() && CS.getCalleeNode()->getNumReferrers() == 1 &&
1160 CS.getCalleeNode()->getNodeFlags() == 0) { // No useful info?
1161 std::cerr << "WARNING: Useless call site found??\n";
1162 CS.swap(Calls.back());
1166 // If the return value or any arguments point to a void node with no
1167 // information at all in it, and the call node is the only node to point
1168 // to it, remove the edge to the node (killing the node).
1170 killIfUselessEdge(CS.getRetVal());
1171 for (unsigned a = 0, e = CS.getNumPtrArgs(); a != e; ++a)
1172 killIfUselessEdge(CS.getPtrArg(a));
1174 // If this call site calls the same function as the last call site, and if
1175 // the function pointer contains an external function, this node will
1176 // never be resolved. Merge the arguments of the call node because no
1177 // information will be lost.
1179 if ((CS.isDirectCall() && CS.getCalleeFunc() == LastCalleeFunc) ||
1180 (CS.isIndirectCall() && CS.getCalleeNode() == LastCalleeNode)) {
1181 ++NumDuplicateCalls;
1182 if (NumDuplicateCalls == 1) {
1184 LastCalleeContainsExternalFunction =
1185 nodeContainsExternalFunction(LastCalleeNode);
1187 LastCalleeContainsExternalFunction = LastCalleeFunc->isExternal();
1191 if (LastCalleeContainsExternalFunction ||
1192 // This should be more than enough context sensitivity!
1193 // FIXME: Evaluate how many times this is tripped!
1194 NumDuplicateCalls > 20) {
1195 DSCallSite &OCS = Calls[i-1];
1198 // The node will now be eliminated as a duplicate!
1199 if (CS.getNumPtrArgs() < OCS.getNumPtrArgs())
1201 else if (CS.getNumPtrArgs() > OCS.getNumPtrArgs())
1206 if (CS.isDirectCall()) {
1207 LastCalleeFunc = CS.getCalleeFunc();
1210 LastCalleeNode = CS.getCalleeNode();
1213 NumDuplicateCalls = 0;
1218 Calls.erase(std::unique(Calls.begin(), Calls.end()),
1221 // Track the number of call nodes merged away...
1222 NumCallNodesMerged += NumFns-Calls.size();
1224 DEBUG(if (NumFns != Calls.size())
1225 std::cerr << "Merged " << (NumFns-Calls.size()) << " call nodes.\n";);
1229 // removeTriviallyDeadNodes - After the graph has been constructed, this method
1230 // removes all unreachable nodes that are created because they got merged with
1231 // other nodes in the graph. These nodes will all be trivially unreachable, so
1232 // we don't have to perform any non-trivial analysis here.
1234 void DSGraph::removeTriviallyDeadNodes() {
1235 removeIdenticalCalls(FunctionCalls);
1236 removeIdenticalCalls(AuxFunctionCalls);
1238 // Loop over all of the nodes in the graph, calling getNode on each field.
1239 // This will cause all nodes to update their forwarding edges, causing
1240 // forwarded nodes to be delete-able.
1241 for (unsigned i = 0, e = Nodes.size(); i != e; ++i) {
1242 DSNode *N = Nodes[i];
1243 for (unsigned l = 0, e = N->getNumLinks(); l != e; ++l)
1244 N->getLink(l*N->getPointerSize()).getNode();
1247 // Likewise, forward any edges from the scalar nodes...
1248 for (ScalarMapTy::iterator I = ScalarMap.begin(), E = ScalarMap.end();
1250 I->second.getNode();
1252 bool isGlobalsGraph = !GlobalsGraph;
1254 for (unsigned i = 0; i != Nodes.size(); ++i) {
1255 DSNode *Node = Nodes[i];
1257 // Do not remove *any* global nodes in the globals graph.
1258 // This is a special case because such nodes may not have I, M, R flags set.
1259 if (Node->isGlobalNode() && isGlobalsGraph)
1262 if (Node->isComplete() && !Node->isModified() && !Node->isRead()) {
1263 // This is a useless node if it has no mod/ref info (checked above),
1264 // outgoing edges (which it cannot, as it is not modified in this
1265 // context), and it has no incoming edges. If it is a global node it may
1266 // have all of these properties and still have incoming edges, due to the
1267 // scalar map, so we check those now.
1269 if (Node->getNumReferrers() == Node->getGlobals().size()) {
1270 const std::vector<GlobalValue*> &Globals = Node->getGlobals();
1272 // Loop through and make sure all of the globals are referring directly
1274 for (unsigned j = 0, e = Globals.size(); j != e; ++j) {
1275 DSNode *N = ScalarMap.find(Globals[j])->second.getNode();
1276 assert(N == Node && "ScalarMap doesn't match globals list!");
1279 // Make sure NumReferrers still agrees, if so, the node is truly dead.
1280 if (Node->getNumReferrers() == Globals.size()) {
1281 for (unsigned j = 0, e = Globals.size(); j != e; ++j)
1282 ScalarMap.erase(Globals[j]);
1283 Node->makeNodeDead();
1287 #ifdef SANER_CODE_FOR_CHECKING_IF_ALL_REFERRERS_ARE_FROM_SCALARMAP
1289 // *** It seems to me that we should be able to simply check if
1290 // *** there are fewer or equal #referrers as #globals and make
1291 // *** sure that all those referrers are in the scalar map?
1293 if (Node->getNumReferrers() <= Node->getGlobals().size()) {
1294 const std::vector<GlobalValue*> &Globals = Node->getGlobals();
1297 // Loop through and make sure all of the globals are referring directly
1299 for (unsigned j = 0, e = Globals.size(); j != e; ++j) {
1300 DSNode *N = ScalarMap.find(Globals[j])->second.getNode();
1301 assert(N == Node && "ScalarMap doesn't match globals list!");
1305 // Make sure NumReferrers still agrees. The node is truly dead.
1306 assert(Node->getNumReferrers() == Globals.size());
1307 for (unsigned j = 0, e = Globals.size(); j != e; ++j)
1308 ScalarMap.erase(Globals[j]);
1309 Node->makeNodeDead();
1314 if (Node->getNodeFlags() == 0 && Node->hasNoReferrers()) {
1315 // This node is dead!
1316 delete Node; // Free memory...
1317 Nodes[i--] = Nodes.back();
1318 Nodes.pop_back(); // Remove from node list...
1324 /// markReachableNodes - This method recursively traverses the specified
1325 /// DSNodes, marking any nodes which are reachable. All reachable nodes it adds
1326 /// to the set, which allows it to only traverse visited nodes once.
1328 void DSNode::markReachableNodes(hash_set<DSNode*> &ReachableNodes) {
1329 if (this == 0) return;
1330 assert(getForwardNode() == 0 && "Cannot mark a forwarded node!");
1331 if (ReachableNodes.count(this)) return; // Already marked reachable
1332 ReachableNodes.insert(this); // Is reachable now
1334 for (unsigned i = 0, e = getSize(); i < e; i += DS::PointerSize)
1335 getLink(i).getNode()->markReachableNodes(ReachableNodes);
1338 void DSCallSite::markReachableNodes(hash_set<DSNode*> &Nodes) {
1339 getRetVal().getNode()->markReachableNodes(Nodes);
1340 if (isIndirectCall()) getCalleeNode()->markReachableNodes(Nodes);
1342 for (unsigned i = 0, e = getNumPtrArgs(); i != e; ++i)
1343 getPtrArg(i).getNode()->markReachableNodes(Nodes);
1346 // CanReachAliveNodes - Simple graph walker that recursively traverses the graph
1347 // looking for a node that is marked alive. If an alive node is found, return
1348 // true, otherwise return false. If an alive node is reachable, this node is
1349 // marked as alive...
1351 static bool CanReachAliveNodes(DSNode *N, hash_set<DSNode*> &Alive,
1352 hash_set<DSNode*> &Visited,
1353 bool IgnoreGlobals) {
1354 if (N == 0) return false;
1355 assert(N->getForwardNode() == 0 && "Cannot mark a forwarded node!");
1357 // If this is a global node, it will end up in the globals graph anyway, so we
1358 // don't need to worry about it.
1359 if (IgnoreGlobals && N->isGlobalNode()) return false;
1361 // If we know that this node is alive, return so!
1362 if (Alive.count(N)) return true;
1364 // Otherwise, we don't think the node is alive yet, check for infinite
1366 if (Visited.count(N)) return false; // Found a cycle
1367 Visited.insert(N); // No recursion, insert into Visited...
1369 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
1370 if (CanReachAliveNodes(N->getLink(i).getNode(), Alive, Visited,
1372 N->markReachableNodes(Alive);
1378 // CallSiteUsesAliveArgs - Return true if the specified call site can reach any
1381 static bool CallSiteUsesAliveArgs(DSCallSite &CS, hash_set<DSNode*> &Alive,
1382 hash_set<DSNode*> &Visited,
1383 bool IgnoreGlobals) {
1384 if (CanReachAliveNodes(CS.getRetVal().getNode(), Alive, Visited,
1387 if (CS.isIndirectCall() &&
1388 CanReachAliveNodes(CS.getCalleeNode(), Alive, Visited, IgnoreGlobals))
1390 for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i)
1391 if (CanReachAliveNodes(CS.getPtrArg(i).getNode(), Alive, Visited,
1397 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
1398 // subgraphs that are unreachable. This often occurs because the data
1399 // structure doesn't "escape" into it's caller, and thus should be eliminated
1400 // from the caller's graph entirely. This is only appropriate to use when
1403 void DSGraph::removeDeadNodes(unsigned Flags) {
1404 DEBUG(AssertGraphOK(); GlobalsGraph->AssertGraphOK());
1406 // Reduce the amount of work we have to do... remove dummy nodes left over by
1408 removeTriviallyDeadNodes();
1410 // FIXME: Merge non-trivially identical call nodes...
1412 // Alive - a set that holds all nodes found to be reachable/alive.
1413 hash_set<DSNode*> Alive;
1414 std::vector<std::pair<Value*, DSNode*> > GlobalNodes;
1416 // Mark all nodes reachable by (non-global) scalar nodes as alive...
1417 for (ScalarMapTy::iterator I = ScalarMap.begin(), E = ScalarMap.end(); I !=E;)
1418 if (isa<GlobalValue>(I->first)) { // Keep track of global nodes
1419 assert(I->second.getNode() && "Null global node?");
1420 assert(I->second.getNode()->isGlobalNode() && "Should be a global node!");
1421 GlobalNodes.push_back(std::make_pair(I->first, I->second.getNode()));
1424 // Check to see if this is a worthless node generated for non-pointer
1425 // values, such as integers. Consider an addition of long types: A+B.
1426 // Assuming we can track all uses of the value in this context, and it is
1427 // NOT used as a pointer, we can delete the node. We will be able to
1428 // detect this situation if the node pointed to ONLY has Unknown bit set
1429 // in the node. In this case, the node is not incomplete, does not point
1430 // to any other nodes (no mod/ref bits set), and is therefore
1431 // uninteresting for data structure analysis. If we run across one of
1432 // these, prune the scalar pointing to it.
1434 DSNode *N = I->second.getNode();
1435 if (N->getNodeFlags() == DSNode::UnknownNode && !isa<Argument>(I->first)){
1436 ScalarMap.erase(I++);
1438 I->second.getNode()->markReachableNodes(Alive);
1443 // The return value is alive as well...
1444 for (ReturnNodesTy::iterator I = ReturnNodes.begin(), E = ReturnNodes.end();
1446 I->second.getNode()->markReachableNodes(Alive);
1448 // Mark any nodes reachable by primary calls as alive...
1449 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
1450 FunctionCalls[i].markReachableNodes(Alive);
1452 // Copy and merge all information about globals to the GlobalsGraph
1453 // if this is not a final pass (where unreachable globals are removed)
1454 NodeMapTy GlobalNodeMap;
1455 hash_set<const DSNode*> GlobalNodeSet;
1457 for (std::vector<std::pair<Value*, DSNode*> >::const_iterator
1458 I = GlobalNodes.begin(), E = GlobalNodes.end(); I != E; ++I)
1459 GlobalNodeSet.insert(I->second); // put global nodes into a set
1461 // Now find globals and aux call nodes that are already live or reach a live
1462 // value (which makes them live in turn), and continue till no more are found.
1465 hash_set<DSNode*> Visited;
1466 std::vector<unsigned char> AuxFCallsAlive(AuxFunctionCalls.size());
1469 // If any global node points to a non-global that is "alive", the global is
1470 // "alive" as well... Remove it from the GlobalNodes list so we only have
1471 // unreachable globals in the list.
1474 if (!(Flags & DSGraph::RemoveUnreachableGlobals))
1475 for (unsigned i = 0; i != GlobalNodes.size(); ++i)
1476 if (CanReachAliveNodes(GlobalNodes[i].second, Alive, Visited,
1477 Flags & DSGraph::RemoveUnreachableGlobals)) {
1478 std::swap(GlobalNodes[i--], GlobalNodes.back()); // Move to end to...
1479 GlobalNodes.pop_back(); // erase efficiently
1483 // Mark only unresolvable call nodes for moving to the GlobalsGraph since
1484 // call nodes that get resolved will be difficult to remove from that graph.
1485 // The final unresolved call nodes must be handled specially at the end of
1486 // the BU pass (i.e., in main or other roots of the call graph).
1487 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
1488 if (!AuxFCallsAlive[i] &&
1489 (AuxFunctionCalls[i].isIndirectCall()
1490 || CallSiteUsesAliveArgs(AuxFunctionCalls[i], Alive, Visited,
1491 Flags & DSGraph::RemoveUnreachableGlobals))) {
1492 AuxFunctionCalls[i].markReachableNodes(Alive);
1493 AuxFCallsAlive[i] = true;
1498 // Move dead aux function calls to the end of the list
1499 unsigned CurIdx = 0;
1500 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
1501 if (AuxFCallsAlive[i])
1502 AuxFunctionCalls[CurIdx++].swap(AuxFunctionCalls[i]);
1504 // Copy and merge all global nodes and dead aux call nodes into the
1505 // GlobalsGraph, and all nodes reachable from those nodes
1507 if (!(Flags & DSGraph::RemoveUnreachableGlobals)) {
1509 // First, add the dead aux call nodes to the set of root nodes for cloning
1510 // -- return value at this call site, if any
1511 // -- actual arguments passed at this call site
1512 // -- callee node at this call site, if this is an indirect call
1513 for (unsigned i = CurIdx, e = AuxFunctionCalls.size(); i != e; ++i) {
1514 if (const DSNode* RetNode = AuxFunctionCalls[i].getRetVal().getNode())
1515 GlobalNodeSet.insert(RetNode);
1516 for (unsigned j=0, N=AuxFunctionCalls[i].getNumPtrArgs(); j < N; ++j)
1517 if (const DSNode* ArgTarget=AuxFunctionCalls[i].getPtrArg(j).getNode())
1518 GlobalNodeSet.insert(ArgTarget);
1519 if (AuxFunctionCalls[i].isIndirectCall())
1520 GlobalNodeSet.insert(AuxFunctionCalls[i].getCalleeNode());
1523 // There are no "pre-completed" nodes so use any empty map for those.
1524 // Strip all alloca bits since the current function is only for the BU pass.
1525 // Strip all incomplete bits since they are short-lived properties and they
1526 // will be correctly computed when rematerializing nodes into the functions.
1528 NodeMapTy CompletedMap;
1529 GlobalsGraph->cloneReachableSubgraph(*this, GlobalNodeSet,
1530 GlobalNodeMap, CompletedMap,
1531 (DSGraph::StripAllocaBit |
1532 DSGraph::StripIncompleteBit));
1535 // Remove all dead aux function calls...
1536 if (!(Flags & DSGraph::RemoveUnreachableGlobals)) {
1537 assert(GlobalsGraph && "No globals graph available??");
1539 // Copy the unreachable call nodes to the globals graph, updating
1540 // their target pointers using the GlobalNodeMap
1541 for (unsigned i = CurIdx, e = AuxFunctionCalls.size(); i != e; ++i)
1542 GlobalsGraph->AuxFunctionCalls.push_back(DSCallSite(AuxFunctionCalls[i],
1545 // Crop all the useless ones out...
1546 AuxFunctionCalls.erase(AuxFunctionCalls.begin()+CurIdx,
1547 AuxFunctionCalls.end());
1549 // We are finally done with the GlobalNodeMap so we can clear it and
1550 // then get rid of unused nodes in the GlobalsGraph produced by merging.
1551 GlobalNodeMap.clear();
1552 GlobalsGraph->removeTriviallyDeadNodes();
1554 // At this point, any nodes which are visited, but not alive, are nodes
1555 // which can be removed. Loop over all nodes, eliminating completely
1556 // unreachable nodes.
1558 std::vector<DSNode*> DeadNodes;
1559 DeadNodes.reserve(Nodes.size());
1560 for (unsigned i = 0; i != Nodes.size(); ++i)
1561 if (!Alive.count(Nodes[i])) {
1562 DSNode *N = Nodes[i];
1563 Nodes[i--] = Nodes.back(); // move node to end of vector
1564 Nodes.pop_back(); // Erase node from alive list.
1565 DeadNodes.push_back(N);
1566 N->dropAllReferences();
1568 assert(Nodes[i]->getForwardNode() == 0 && "Alive forwarded node?");
1571 // Remove all unreachable globals from the ScalarMap.
1572 // If flag RemoveUnreachableGlobals is set, GlobalNodes has only dead nodes.
1573 // In either case, the dead nodes will not be in the set Alive.
1574 for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i) {
1575 assert(((Flags & DSGraph::RemoveUnreachableGlobals) ||
1576 !Alive.count(GlobalNodes[i].second)) && "huh? non-dead global");
1577 if (!Alive.count(GlobalNodes[i].second))
1578 ScalarMap.erase(GlobalNodes[i].first);
1581 // Delete all dead nodes now since their referrer counts are zero.
1582 for (unsigned i = 0, e = DeadNodes.size(); i != e; ++i)
1583 delete DeadNodes[i];
1585 DEBUG(AssertGraphOK(); GlobalsGraph->AssertGraphOK());
1588 void DSGraph::AssertGraphOK() const {
1589 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
1590 Nodes[i]->assertOK();
1592 for (ScalarMapTy::const_iterator I = ScalarMap.begin(),
1593 E = ScalarMap.end(); I != E; ++I) {
1594 assert(I->second.getNode() && "Null node in scalarmap!");
1595 AssertNodeInGraph(I->second.getNode());
1596 if (GlobalValue *GV = dyn_cast<GlobalValue>(I->first)) {
1597 assert(I->second.getNode()->isGlobalNode() &&
1598 "Global points to node, but node isn't global?");
1599 AssertNodeContainsGlobal(I->second.getNode(), GV);
1602 AssertCallNodesInGraph();
1603 AssertAuxCallNodesInGraph();
1606 /// mergeInGlobalsGraph - This method is useful for clients to incorporate the
1607 /// globals graph into the DS, BU or TD graph for a function. This code retains
1608 /// all globals, i.e., does not delete unreachable globals after they are
1611 void DSGraph::mergeInGlobalsGraph() {
1612 NodeMapTy GlobalNodeMap;
1613 ScalarMapTy OldValMap;
1614 ReturnNodesTy OldRetNodes;
1615 cloneInto(*GlobalsGraph, OldValMap, OldRetNodes, GlobalNodeMap,
1616 DSGraph::KeepAllocaBit | DSGraph::DontCloneCallNodes |
1617 DSGraph::DontCloneAuxCallNodes);
1619 // Now merge existing global nodes in the GlobalsGraph with their copies
1620 for (ScalarMapTy::iterator I = ScalarMap.begin(), E = ScalarMap.end();
1622 if (isa<GlobalValue>(I->first)) { // Found a global node
1623 DSNodeHandle &GH = I->second;
1624 DSNodeHandle &GGNodeH = GlobalsGraph->getScalarMap()[I->first];
1625 GH.mergeWith(GlobalNodeMap[GGNodeH.getNode()]);
1628 // Merging leaves behind unused nodes: get rid of them now.
1629 GlobalNodeMap.clear();
1631 OldRetNodes.clear();
1632 removeTriviallyDeadNodes();