1 //===- DataStructure.cpp - Implement the core data structure analysis -----===//
3 // This file implements the core data structure functionality.
5 //===----------------------------------------------------------------------===//
7 #include "llvm/Analysis/DSGraph.h"
8 #include "llvm/Function.h"
9 #include "llvm/iOther.h"
10 #include "llvm/DerivedTypes.h"
11 #include "llvm/Target/TargetData.h"
12 #include "Support/STLExtras.h"
13 #include "Support/Statistic.h"
14 #include "Support/Timer.h"
21 Statistic<> NumFolds ("dsnode", "Number of nodes completely folded");
22 Statistic<> NumCallNodesMerged("dsnode", "Number of call nodes merged");
25 namespace DS { // TODO: FIXME
30 //===----------------------------------------------------------------------===//
31 // DSNode Implementation
32 //===----------------------------------------------------------------------===//
34 DSNode::DSNode(enum NodeTy NT, const Type *T)
35 : Ty(Type::VoidTy), Size(0), NodeType(NT) {
36 // Add the type entry if it is specified...
37 if (T) mergeTypeInfo(T, 0);
40 // DSNode copy constructor... do not copy over the referrers list!
41 DSNode::DSNode(const DSNode &N)
42 : Links(N.Links), Globals(N.Globals), Ty(N.Ty), Size(N.Size),
43 NodeType(N.NodeType) {
46 void DSNode::removeReferrer(DSNodeHandle *H) {
47 // Search backwards, because we depopulate the list from the back for
48 // efficiency (because it's a vector).
49 vector<DSNodeHandle*>::reverse_iterator I =
50 std::find(Referrers.rbegin(), Referrers.rend(), H);
51 assert(I != Referrers.rend() && "Referrer not pointing to node!");
52 Referrers.erase(I.base()-1);
55 // addGlobal - Add an entry for a global value to the Globals list. This also
56 // marks the node with the 'G' flag if it does not already have it.
58 void DSNode::addGlobal(GlobalValue *GV) {
59 // Keep the list sorted.
60 vector<GlobalValue*>::iterator I =
61 std::lower_bound(Globals.begin(), Globals.end(), GV);
63 if (I == Globals.end() || *I != GV) {
64 //assert(GV->getType()->getElementType() == Ty);
65 Globals.insert(I, GV);
66 NodeType |= GlobalNode;
70 /// foldNodeCompletely - If we determine that this node has some funny
71 /// behavior happening to it that we cannot represent, we fold it down to a
72 /// single, completely pessimistic, node. This node is represented as a
73 /// single byte with a single TypeEntry of "void".
75 void DSNode::foldNodeCompletely() {
76 if (isNodeCompletelyFolded()) return;
80 // We are no longer typed at all...
85 // Loop over all of our referrers, making them point to our zero bytes of
87 for (vector<DSNodeHandle*>::iterator I = Referrers.begin(), E=Referrers.end();
91 // If we have links, merge all of our outgoing links together...
92 for (unsigned i = 1, e = Links.size(); i < e; ++i)
93 Links[0].mergeWith(Links[i]);
97 /// isNodeCompletelyFolded - Return true if this node has been completely
98 /// folded down to something that can never be expanded, effectively losing
99 /// all of the field sensitivity that may be present in the node.
101 bool DSNode::isNodeCompletelyFolded() const {
102 return getSize() == 1 && Ty == Type::VoidTy && isArray();
106 /// mergeTypeInfo - This method merges the specified type into the current node
107 /// at the specified offset. This may update the current node's type record if
108 /// this gives more information to the node, it may do nothing to the node if
109 /// this information is already known, or it may merge the node completely (and
110 /// return true) if the information is incompatible with what is already known.
112 /// This method returns true if the node is completely folded, otherwise false.
114 bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset) {
115 // Check to make sure the Size member is up-to-date. Size can be one of the
117 // Size = 0, Ty = Void: Nothing is known about this node.
118 // Size = 0, Ty = FnTy: FunctionPtr doesn't have a size, so we use zero
119 // Size = 1, Ty = Void, Array = 1: The node is collapsed
120 // Otherwise, sizeof(Ty) = Size
122 assert(((Size == 0 && Ty == Type::VoidTy && !isArray()) ||
123 (Size == 0 && !Ty->isSized() && !isArray()) ||
124 (Size == 1 && Ty == Type::VoidTy && isArray()) ||
125 (Size == 0 && !Ty->isSized() && !isArray()) ||
126 (TD.getTypeSize(Ty) == Size)) &&
127 "Size member of DSNode doesn't match the type structure!");
128 assert(NewTy != Type::VoidTy && "Cannot merge void type into DSNode!");
130 if (Offset == 0 && NewTy == Ty)
131 return false; // This should be a common case, handle it efficiently
133 // Return true immediately if the node is completely folded.
134 if (isNodeCompletelyFolded()) return true;
136 // If this is an array type, eliminate the outside arrays because they won't
137 // be used anyway. This greatly reduces the size of large static arrays used
138 // as global variables, for example.
140 bool WillBeArray = false;
141 while (const ArrayType *AT = dyn_cast<ArrayType>(NewTy)) {
142 // FIXME: we might want to keep small arrays, but must be careful about
143 // things like: [2 x [10000 x int*]]
144 NewTy = AT->getElementType();
148 // Figure out how big the new type we're merging in is...
149 unsigned NewTySize = NewTy->isSized() ? TD.getTypeSize(NewTy) : 0;
151 // Otherwise check to see if we can fold this type into the current node. If
152 // we can't, we fold the node completely, if we can, we potentially update our
155 if (Ty == Type::VoidTy) {
156 // If this is the first type that this node has seen, just accept it without
158 assert(Offset == 0 && "Cannot have an offset into a void node!");
159 assert(!isArray() && "This shouldn't happen!");
162 if (WillBeArray) NodeType |= Array;
165 // Calculate the number of outgoing links from this node.
166 Links.resize((Size+DS::PointerSize-1) >> DS::PointerShift);
170 // Handle node expansion case here...
171 if (Offset+NewTySize > Size) {
172 // It is illegal to grow this node if we have treated it as an array of
175 foldNodeCompletely();
179 if (Offset) { // We could handle this case, but we don't for now...
180 DEBUG(std::cerr << "UNIMP: Trying to merge a growth type into "
181 << "offset != 0: Collapsing!\n");
182 foldNodeCompletely();
186 // Okay, the situation is nice and simple, we are trying to merge a type in
187 // at offset 0 that is bigger than our current type. Implement this by
188 // switching to the new type and then merge in the smaller one, which should
189 // hit the other code path here. If the other code path decides it's not
190 // ok, it will collapse the node as appropriate.
192 const Type *OldTy = Ty;
195 if (WillBeArray) NodeType |= Array;
198 // Must grow links to be the appropriate size...
199 Links.resize((Size+DS::PointerSize-1) >> DS::PointerShift);
201 // Merge in the old type now... which is guaranteed to be smaller than the
203 return mergeTypeInfo(OldTy, 0);
206 assert(Offset <= Size &&
207 "Cannot merge something into a part of our type that doesn't exist!");
209 // Find the section of Ty that NewTy overlaps with... first we find the
210 // type that starts at offset Offset.
213 const Type *SubType = Ty;
215 assert(Offset-O < TD.getTypeSize(SubType) && "Offset out of range!");
217 switch (SubType->getPrimitiveID()) {
218 case Type::StructTyID: {
219 const StructType *STy = cast<StructType>(SubType);
220 const StructLayout &SL = *TD.getStructLayout(STy);
222 unsigned i = 0, e = SL.MemberOffsets.size();
223 for (; i+1 < e && SL.MemberOffsets[i+1] <= Offset-O; ++i)
226 // The offset we are looking for must be in the i'th element...
227 SubType = STy->getElementTypes()[i];
228 O += SL.MemberOffsets[i];
231 case Type::ArrayTyID: {
232 SubType = cast<ArrayType>(SubType)->getElementType();
233 unsigned ElSize = TD.getTypeSize(SubType);
234 unsigned Remainder = (Offset-O) % ElSize;
235 O = Offset-Remainder;
239 assert(0 && "Unknown type!");
243 assert(O == Offset && "Could not achieve the correct offset!");
245 // If we found our type exactly, early exit
246 if (SubType == NewTy) return false;
248 // Okay, so we found the leader type at the offset requested. Search the list
249 // of types that starts at this offset. If SubType is currently an array or
250 // structure, the type desired may actually be the first element of the
253 unsigned SubTypeSize = SubType->isSized() ? TD.getTypeSize(SubType) : 0;
254 unsigned PadSize = SubTypeSize; // Size, including pad memory which is ignored
255 while (SubType != NewTy) {
256 const Type *NextSubType = 0;
257 unsigned NextSubTypeSize = 0;
258 unsigned NextPadSize = 0;
259 switch (SubType->getPrimitiveID()) {
260 case Type::StructTyID: {
261 const StructType *STy = cast<StructType>(SubType);
262 const StructLayout &SL = *TD.getStructLayout(STy);
263 if (SL.MemberOffsets.size() > 1)
264 NextPadSize = SL.MemberOffsets[1];
266 NextPadSize = SubTypeSize;
267 NextSubType = STy->getElementTypes()[0];
268 NextSubTypeSize = TD.getTypeSize(NextSubType);
271 case Type::ArrayTyID:
272 NextSubType = cast<ArrayType>(SubType)->getElementType();
273 NextSubTypeSize = TD.getTypeSize(NextSubType);
274 NextPadSize = NextSubTypeSize;
280 if (NextSubType == 0)
281 break; // In the default case, break out of the loop
283 if (NextPadSize < NewTySize)
284 break; // Don't allow shrinking to a smaller type than NewTySize
285 SubType = NextSubType;
286 SubTypeSize = NextSubTypeSize;
287 PadSize = NextPadSize;
290 // If we found the type exactly, return it...
291 if (SubType == NewTy)
294 // Check to see if we have a compatible, but different type...
295 if (NewTySize == SubTypeSize) {
296 // Check to see if this type is obviously convertable... int -> uint f.e.
297 if (NewTy->isLosslesslyConvertableTo(SubType))
300 // Check to see if we have a pointer & integer mismatch going on here,
301 // loading a pointer as a long, for example.
303 if (SubType->isInteger() && isa<PointerType>(NewTy) ||
304 NewTy->isInteger() && isa<PointerType>(SubType))
306 } else if (NewTySize > SubTypeSize && NewTySize <= PadSize) {
307 // We are accessing the field, plus some structure padding. Ignore the
308 // structure padding.
313 DEBUG(std::cerr << "MergeTypeInfo Folding OrigTy: " << Ty
314 << "\n due to:" << NewTy << " @ " << Offset << "!\n"
315 << "SubType: " << SubType << "\n\n");
317 foldNodeCompletely();
323 // addEdgeTo - Add an edge from the current node to the specified node. This
324 // can cause merging of nodes in the graph.
326 void DSNode::addEdgeTo(unsigned Offset, const DSNodeHandle &NH) {
327 if (NH.getNode() == 0) return; // Nothing to do
329 DSNodeHandle &ExistingEdge = getLink(Offset);
330 if (ExistingEdge.getNode()) {
331 // Merge the two nodes...
332 ExistingEdge.mergeWith(NH);
333 } else { // No merging to perform...
334 setLink(Offset, NH); // Just force a link in there...
339 // MergeSortedVectors - Efficiently merge a vector into another vector where
340 // duplicates are not allowed and both are sorted. This assumes that 'T's are
341 // efficiently copyable and have sane comparison semantics.
343 static void MergeSortedVectors(vector<GlobalValue*> &Dest,
344 const vector<GlobalValue*> &Src) {
345 // By far, the most common cases will be the simple ones. In these cases,
346 // avoid having to allocate a temporary vector...
348 if (Src.empty()) { // Nothing to merge in...
350 } else if (Dest.empty()) { // Just copy the result in...
352 } else if (Src.size() == 1) { // Insert a single element...
353 const GlobalValue *V = Src[0];
354 vector<GlobalValue*>::iterator I =
355 std::lower_bound(Dest.begin(), Dest.end(), V);
356 if (I == Dest.end() || *I != Src[0]) // If not already contained...
357 Dest.insert(I, Src[0]);
358 } else if (Dest.size() == 1) {
359 GlobalValue *Tmp = Dest[0]; // Save value in temporary...
360 Dest = Src; // Copy over list...
361 vector<GlobalValue*>::iterator I =
362 std::lower_bound(Dest.begin(), Dest.end(), Tmp);
363 if (I == Dest.end() || *I != Tmp) // If not already contained...
367 // Make a copy to the side of Dest...
368 vector<GlobalValue*> Old(Dest);
370 // Make space for all of the type entries now...
371 Dest.resize(Dest.size()+Src.size());
373 // Merge the two sorted ranges together... into Dest.
374 std::merge(Old.begin(), Old.end(), Src.begin(), Src.end(), Dest.begin());
376 // Now erase any duplicate entries that may have accumulated into the
377 // vectors (because they were in both of the input sets)
378 Dest.erase(std::unique(Dest.begin(), Dest.end()), Dest.end());
383 // MergeNodes() - Helper function for DSNode::mergeWith().
384 // This function does the hard work of merging two nodes, CurNodeH
385 // and NH after filtering out trivial cases and making sure that
386 // CurNodeH.offset >= NH.offset.
389 // Since merging may cause either node to go away, we must always
390 // use the node-handles to refer to the nodes. These node handles are
391 // automatically updated during merging, so will always provide access
392 // to the correct node after a merge.
394 void DSNode::MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH) {
395 assert(CurNodeH.getOffset() >= NH.getOffset() &&
396 "This should have been enforced in the caller.");
398 // Now we know that Offset >= NH.Offset, so convert it so our "Offset" (with
399 // respect to NH.Offset) is now zero. NOffset is the distance from the base
400 // of our object that N starts from.
402 unsigned NOffset = CurNodeH.getOffset()-NH.getOffset();
403 unsigned NSize = NH.getNode()->getSize();
405 // Merge the type entries of the two nodes together...
406 if (NH.getNode()->Ty != Type::VoidTy) {
407 CurNodeH.getNode()->mergeTypeInfo(NH.getNode()->Ty, NOffset);
409 assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
411 // If we are merging a node with a completely folded node, then both nodes are
412 // now completely folded.
414 if (CurNodeH.getNode()->isNodeCompletelyFolded()) {
415 if (!NH.getNode()->isNodeCompletelyFolded()) {
416 NH.getNode()->foldNodeCompletely();
417 assert(NH.getOffset()==0 && "folding did not make offset 0?");
418 NOffset = NH.getOffset();
419 NSize = NH.getNode()->getSize();
420 assert(NOffset == 0 && NSize == 1);
422 } else if (NH.getNode()->isNodeCompletelyFolded()) {
423 CurNodeH.getNode()->foldNodeCompletely();
424 assert(CurNodeH.getOffset()==0 && "folding did not make offset 0?");
425 NOffset = NH.getOffset();
426 NSize = NH.getNode()->getSize();
427 assert(NOffset == 0 && NSize == 1);
430 if (CurNodeH.getNode() == NH.getNode() || NH.getNode() == 0) return;
431 assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
433 // Remove all edges pointing at N, causing them to point to 'this' instead.
434 // Make sure to adjust their offset, not just the node pointer.
435 // Also, be careful to use the DSNode* rather than NH since NH is one of
436 // the referrers and once NH refers to CurNodeH.getNode() this will
437 // become an infinite loop.
438 DSNode* N = NH.getNode();
439 unsigned OldNHOffset = NH.getOffset();
440 while (!N->Referrers.empty()) {
441 DSNodeHandle &Ref = *N->Referrers.back();
442 Ref = DSNodeHandle(CurNodeH.getNode(), NOffset+Ref.getOffset());
444 NH = DSNodeHandle(N, OldNHOffset); // reset NH to point back to where it was
446 assert((CurNodeH.getNode()->NodeType & DSNode::DEAD) == 0);
448 // Make all of the outgoing links of *NH now be outgoing links of
449 // this. This can cause recursive merging!
451 for (unsigned i = 0; i < NH.getNode()->getSize(); i += DS::PointerSize) {
452 DSNodeHandle &Link = NH.getNode()->getLink(i);
453 if (Link.getNode()) {
454 // Compute the offset into the current node at which to
455 // merge this link. In the common case, this is a linear
456 // relation to the offset in the original node (with
457 // wrapping), but if the current node gets collapsed due to
458 // recursive merging, we must make sure to merge in all remaining
459 // links at offset zero.
460 unsigned MergeOffset = 0;
461 if (CurNodeH.getNode()->Size != 1)
462 MergeOffset = (i+NOffset) % CurNodeH.getNode()->getSize();
463 CurNodeH.getNode()->addEdgeTo(MergeOffset, Link);
467 // Now that there are no outgoing edges, all of the Links are dead.
468 NH.getNode()->Links.clear();
469 NH.getNode()->Size = 0;
470 NH.getNode()->Ty = Type::VoidTy;
472 // Merge the node types
473 CurNodeH.getNode()->NodeType |= NH.getNode()->NodeType;
474 NH.getNode()->NodeType = DEAD; // NH is now a dead node.
476 // Merge the globals list...
477 if (!NH.getNode()->Globals.empty()) {
478 MergeSortedVectors(CurNodeH.getNode()->Globals, NH.getNode()->Globals);
480 // Delete the globals from the old node...
481 NH.getNode()->Globals.clear();
486 // mergeWith - Merge this node and the specified node, moving all links to and
487 // from the argument node into the current node, deleting the node argument.
488 // Offset indicates what offset the specified node is to be merged into the
491 // The specified node may be a null pointer (in which case, nothing happens).
493 void DSNode::mergeWith(const DSNodeHandle &NH, unsigned Offset) {
494 DSNode *N = NH.getNode();
495 if (N == 0 || (N == this && NH.getOffset() == Offset))
498 assert((N->NodeType & DSNode::DEAD) == 0);
499 assert((NodeType & DSNode::DEAD) == 0);
500 assert(!hasNoReferrers() && "Should not try to fold a useless node!");
503 // We cannot merge two pieces of the same node together, collapse the node
505 DEBUG(std::cerr << "Attempting to merge two chunks of"
506 << " the same node together!\n");
507 foldNodeCompletely();
511 // If both nodes are not at offset 0, make sure that we are merging the node
512 // at an later offset into the node with the zero offset.
514 if (Offset < NH.getOffset()) {
515 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
517 } else if (Offset == NH.getOffset() && getSize() < N->getSize()) {
518 // If the offsets are the same, merge the smaller node into the bigger node
519 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
523 // Ok, now we can merge the two nodes. Use a static helper that works with
524 // two node handles, since "this" may get merged away at intermediate steps.
525 DSNodeHandle CurNodeH(this, Offset);
526 DSNodeHandle NHCopy(NH);
527 DSNode::MergeNodes(CurNodeH, NHCopy);
530 //===----------------------------------------------------------------------===//
531 // DSCallSite Implementation
532 //===----------------------------------------------------------------------===//
534 // Define here to avoid including iOther.h and BasicBlock.h in DSGraph.h
535 Function &DSCallSite::getCaller() const {
536 return *Inst->getParent()->getParent();
540 //===----------------------------------------------------------------------===//
541 // DSGraph Implementation
542 //===----------------------------------------------------------------------===//
544 DSGraph::DSGraph(const DSGraph &G) : Func(G.Func), GlobalsGraph(0) {
545 PrintAuxCalls = false;
546 std::map<const DSNode*, DSNodeHandle> NodeMap;
547 RetNode = cloneInto(G, ScalarMap, NodeMap);
550 DSGraph::DSGraph(const DSGraph &G,
551 std::map<const DSNode*, DSNodeHandle> &NodeMap)
552 : Func(G.Func), GlobalsGraph(0) {
553 PrintAuxCalls = false;
554 RetNode = cloneInto(G, ScalarMap, NodeMap);
557 DSGraph::~DSGraph() {
558 FunctionCalls.clear();
559 AuxFunctionCalls.clear();
563 // Drop all intra-node references, so that assertions don't fail...
564 std::for_each(Nodes.begin(), Nodes.end(),
565 std::mem_fun(&DSNode::dropAllReferences));
567 // Delete all of the nodes themselves...
568 std::for_each(Nodes.begin(), Nodes.end(), deleter<DSNode>);
571 // dump - Allow inspection of graph in a debugger.
572 void DSGraph::dump() const { print(std::cerr); }
575 /// remapLinks - Change all of the Links in the current node according to the
576 /// specified mapping.
578 void DSNode::remapLinks(std::map<const DSNode*, DSNodeHandle> &OldNodeMap) {
579 for (unsigned i = 0, e = Links.size(); i != e; ++i) {
580 DSNodeHandle &H = OldNodeMap[Links[i].getNode()];
581 Links[i].setNode(H.getNode());
582 Links[i].setOffset(Links[i].getOffset()+H.getOffset());
587 // cloneInto - Clone the specified DSGraph into the current graph, returning the
588 // Return node of the graph. The translated ScalarMap for the old function is
589 // filled into the OldValMap member. If StripAllocas is set to true, Alloca
590 // markers are removed from the graph, as the graph is being cloned into a
591 // calling function's graph.
593 DSNodeHandle DSGraph::cloneInto(const DSGraph &G,
594 std::map<Value*, DSNodeHandle> &OldValMap,
595 std::map<const DSNode*, DSNodeHandle> &OldNodeMap,
596 unsigned CloneFlags) {
597 assert(OldNodeMap.empty() && "Returned OldNodeMap should be empty!");
598 assert(&G != this && "Cannot clone graph into itself!");
600 unsigned FN = Nodes.size(); // First new node...
602 // Duplicate all of the nodes, populating the node map...
603 Nodes.reserve(FN+G.Nodes.size());
604 for (unsigned i = 0, e = G.Nodes.size(); i != e; ++i) {
605 DSNode *Old = G.Nodes[i];
606 DSNode *New = new DSNode(*Old);
607 New->NodeType &= ~DSNode::DEAD; // Clear dead flag...
608 Nodes.push_back(New);
609 OldNodeMap[Old] = New;
613 Timer::addPeakMemoryMeasurement();
616 // Rewrite the links in the new nodes to point into the current graph now.
617 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
618 Nodes[i]->remapLinks(OldNodeMap);
620 // Remove alloca markers as specified
621 if (CloneFlags & (StripAllocaBit | StripModRefBits)) {
622 unsigned short clearBits = (CloneFlags & StripAllocaBit
623 ? DSNode::AllocaNode : 0)
624 | (CloneFlags & StripModRefBits
625 ? (DSNode::Modified | DSNode::Read) : 0);
626 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
627 Nodes[i]->NodeType &= ~clearBits;
630 // Copy the value map... and merge all of the global nodes...
631 for (std::map<Value*, DSNodeHandle>::const_iterator I = G.ScalarMap.begin(),
632 E = G.ScalarMap.end(); I != E; ++I) {
633 DSNodeHandle &H = OldValMap[I->first];
634 DSNodeHandle &MappedNode = OldNodeMap[I->second.getNode()];
635 H.setNode(MappedNode.getNode());
636 H.setOffset(I->second.getOffset()+MappedNode.getOffset());
638 if (isa<GlobalValue>(I->first)) { // Is this a global?
639 std::map<Value*, DSNodeHandle>::iterator GVI = ScalarMap.find(I->first);
640 if (GVI != ScalarMap.end()) { // Is the global value in this fn already?
641 GVI->second.mergeWith(H);
643 ScalarMap[I->first] = H; // Add global pointer to this graph
648 if (!(CloneFlags & DontCloneCallNodes)) {
649 // Copy the function calls list...
650 unsigned FC = FunctionCalls.size(); // FirstCall
651 FunctionCalls.reserve(FC+G.FunctionCalls.size());
652 for (unsigned i = 0, ei = G.FunctionCalls.size(); i != ei; ++i)
653 FunctionCalls.push_back(DSCallSite(G.FunctionCalls[i], OldNodeMap));
656 if (!(CloneFlags & DontCloneAuxCallNodes)) {
657 // Copy the auxillary function calls list...
658 unsigned FC = AuxFunctionCalls.size(); // FirstCall
659 AuxFunctionCalls.reserve(FC+G.AuxFunctionCalls.size());
660 for (unsigned i = 0, ei = G.AuxFunctionCalls.size(); i != ei; ++i)
661 AuxFunctionCalls.push_back(DSCallSite(G.AuxFunctionCalls[i], OldNodeMap));
664 // Return the returned node pointer...
665 DSNodeHandle &MappedRet = OldNodeMap[G.RetNode.getNode()];
666 return DSNodeHandle(MappedRet.getNode(),
667 MappedRet.getOffset()+G.RetNode.getOffset());
670 /// mergeInGraph - The method is used for merging graphs together. If the
671 /// argument graph is not *this, it makes a clone of the specified graph, then
672 /// merges the nodes specified in the call site with the formal arguments in the
675 void DSGraph::mergeInGraph(DSCallSite &CS, const DSGraph &Graph,
676 unsigned CloneFlags) {
677 std::map<Value*, DSNodeHandle> OldValMap;
679 std::map<Value*, DSNodeHandle> *ScalarMap = &OldValMap;
681 // If this is not a recursive call, clone the graph into this graph...
682 if (&Graph != this) {
683 // Clone the callee's graph into the current graph, keeping
684 // track of where scalars in the old graph _used_ to point,
685 // and of the new nodes matching nodes of the old graph.
686 std::map<const DSNode*, DSNodeHandle> OldNodeMap;
688 // The clone call may invalidate any of the vectors in the data
689 // structure graph. Strip locals and don't copy the list of callers
690 RetVal = cloneInto(Graph, OldValMap, OldNodeMap, CloneFlags);
691 ScalarMap = &OldValMap;
693 RetVal = getRetNode();
694 ScalarMap = &getScalarMap();
697 // Merge the return value with the return value of the context...
698 RetVal.mergeWith(CS.getRetVal());
700 // Resolve all of the function arguments...
701 Function &F = Graph.getFunction();
702 Function::aiterator AI = F.abegin();
704 for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i, ++AI) {
705 // Advance the argument iterator to the first pointer argument...
706 while (!isPointerType(AI->getType())) {
710 std::cerr << "Bad call to Function: " << F.getName() << "\n";
712 assert(AI != F.aend() && "# Args provided is not # Args required!");
715 // Add the link from the argument scalar to the provided value
716 DSNodeHandle &NH = (*ScalarMap)[AI];
717 assert(NH.getNode() && "Pointer argument without scalarmap entry?");
718 NH.mergeWith(CS.getPtrArg(i));
723 // cloneGlobalInto - Clone the given global node and all its target links
724 // (and all their llinks, recursively).
726 DSNode *DSGraph::cloneGlobalInto(const DSNode *GNode) {
727 if (GNode == 0 || GNode->getGlobals().size() == 0) return 0;
729 // If a clone has already been created for GNode, return it.
730 DSNodeHandle& ValMapEntry = ScalarMap[GNode->getGlobals()[0]];
731 if (ValMapEntry != 0)
734 // Clone the node and update the ValMap.
735 DSNode* NewNode = new DSNode(*GNode);
736 ValMapEntry = NewNode; // j=0 case of loop below!
737 Nodes.push_back(NewNode);
738 for (unsigned j = 1, N = NewNode->getGlobals().size(); j < N; ++j)
739 ScalarMap[NewNode->getGlobals()[j]] = NewNode;
741 // Rewrite the links in the new node to point into the current graph.
742 for (unsigned j = 0, e = GNode->getNumLinks(); j != e; ++j)
743 NewNode->setLink(j, cloneGlobalInto(GNode->getLink(j)));
750 // markIncompleteNodes - Mark the specified node as having contents that are not
751 // known with the current analysis we have performed. Because a node makes all
752 // of the nodes it can reach imcomplete if the node itself is incomplete, we
753 // must recursively traverse the data structure graph, marking all reachable
754 // nodes as incomplete.
756 static void markIncompleteNode(DSNode *N) {
757 // Stop recursion if no node, or if node already marked...
758 if (N == 0 || (N->NodeType & DSNode::Incomplete)) return;
760 // Actually mark the node
761 N->NodeType |= DSNode::Incomplete;
763 // Recusively process children...
764 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
765 if (DSNode *DSN = N->getLink(i).getNode())
766 markIncompleteNode(DSN);
769 static void markIncomplete(DSCallSite &Call) {
770 // Then the return value is certainly incomplete!
771 markIncompleteNode(Call.getRetVal().getNode());
773 // All objects pointed to by function arguments are incomplete!
774 for (unsigned i = 0, e = Call.getNumPtrArgs(); i != e; ++i)
775 markIncompleteNode(Call.getPtrArg(i).getNode());
778 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
779 // modified by other functions that have not been resolved yet. This marks
780 // nodes that are reachable through three sources of "unknownness":
782 // Global Variables, Function Calls, and Incoming Arguments
784 // For any node that may have unknown components (because something outside the
785 // scope of current analysis may have modified it), the 'Incomplete' flag is
786 // added to the NodeType.
788 void DSGraph::markIncompleteNodes(unsigned Flags) {
789 // Mark any incoming arguments as incomplete...
790 if ((Flags & DSGraph::MarkFormalArgs) && Func)
791 for (Function::aiterator I = Func->abegin(), E = Func->aend(); I != E; ++I)
792 if (isPointerType(I->getType()) && ScalarMap.find(I) != ScalarMap.end())
793 markIncompleteNode(ScalarMap[I].getNode());
795 // Mark stuff passed into functions calls as being incomplete...
796 if (!shouldPrintAuxCalls())
797 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
798 markIncomplete(FunctionCalls[i]);
800 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
801 markIncomplete(AuxFunctionCalls[i]);
804 // Mark all of the nodes pointed to by global nodes as incomplete...
805 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
806 if (Nodes[i]->NodeType & DSNode::GlobalNode) {
807 DSNode *N = Nodes[i];
808 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
809 if (DSNode *DSN = N->getLink(i).getNode())
810 markIncompleteNode(DSN);
814 // removeRefsToGlobal - Helper function that removes globals from the
815 // ScalarMap so that the referrer count will go down to zero.
816 static void removeRefsToGlobal(DSNode* N,
817 std::map<Value*, DSNodeHandle> &ScalarMap) {
818 while (!N->getGlobals().empty()) {
819 GlobalValue *GV = N->getGlobals().back();
820 N->getGlobals().pop_back();
826 // isNodeDead - This method checks to see if a node is dead, and if it isn't, it
827 // checks to see if there are simple transformations that it can do to make it
830 bool DSGraph::isNodeDead(DSNode *N) {
831 // Is it a trivially dead shadow node?
832 return N->getReferrers().empty() && (N->NodeType & ~DSNode::DEAD) == 0;
835 static inline void killIfUselessEdge(DSNodeHandle &Edge) {
836 if (DSNode *N = Edge.getNode()) // Is there an edge?
837 if (N->getReferrers().size() == 1) // Does it point to a lonely node?
838 if ((N->NodeType & ~DSNode::Incomplete) == 0 && // No interesting info?
839 N->getType() == Type::VoidTy && !N->isNodeCompletelyFolded())
840 Edge.setNode(0); // Kill the edge!
843 static inline bool nodeContainsExternalFunction(const DSNode *N) {
844 const std::vector<GlobalValue*> &Globals = N->getGlobals();
845 for (unsigned i = 0, e = Globals.size(); i != e; ++i)
846 if (Globals[i]->isExternal())
851 static void removeIdenticalCalls(vector<DSCallSite> &Calls,
852 const std::string &where) {
853 // Remove trivially identical function calls
854 unsigned NumFns = Calls.size();
855 std::sort(Calls.begin(), Calls.end()); // Sort by callee as primary key!
857 // Scan the call list cleaning it up as necessary...
858 DSNode *LastCalleeNode = 0;
859 unsigned NumDuplicateCalls = 0;
860 bool LastCalleeContainsExternalFunction = false;
861 for (unsigned i = 0; i != Calls.size(); ++i) {
862 DSCallSite &CS = Calls[i];
864 // If the Callee is a useless edge, this must be an unreachable call site,
866 killIfUselessEdge(CS.getCallee());
867 if (CS.getCallee().getNode() == 0) {
868 CS.swap(Calls.back());
872 // If the return value or any arguments point to a void node with no
873 // information at all in it, and the call node is the only node to point
874 // to it, remove the edge to the node (killing the node).
876 killIfUselessEdge(CS.getRetVal());
877 for (unsigned a = 0, e = CS.getNumPtrArgs(); a != e; ++a)
878 killIfUselessEdge(CS.getPtrArg(a));
880 // If this call site calls the same function as the last call site, and if
881 // the function pointer contains an external function, this node will
882 // never be resolved. Merge the arguments of the call node because no
883 // information will be lost.
885 if (CS.getCallee().getNode() == LastCalleeNode) {
887 if (NumDuplicateCalls == 1) {
888 LastCalleeContainsExternalFunction =
889 nodeContainsExternalFunction(LastCalleeNode);
892 if (LastCalleeContainsExternalFunction ||
893 // This should be more than enough context sensitivity!
894 // FIXME: Evaluate how many times this is tripped!
895 NumDuplicateCalls > 20) {
896 DSCallSite &OCS = Calls[i-1];
899 // The node will now be eliminated as a duplicate!
900 if (CS.getNumPtrArgs() < OCS.getNumPtrArgs())
902 else if (CS.getNumPtrArgs() > OCS.getNumPtrArgs())
906 LastCalleeNode = CS.getCallee().getNode();
907 NumDuplicateCalls = 0;
912 Calls.erase(std::unique(Calls.begin(), Calls.end()),
915 // Track the number of call nodes merged away...
916 NumCallNodesMerged += NumFns-Calls.size();
918 DEBUG(if (NumFns != Calls.size())
919 std::cerr << "Merged " << (NumFns-Calls.size())
920 << " call nodes in " << where << "\n";);
924 // removeTriviallyDeadNodes - After the graph has been constructed, this method
925 // removes all unreachable nodes that are created because they got merged with
926 // other nodes in the graph. These nodes will all be trivially unreachable, so
927 // we don't have to perform any non-trivial analysis here.
929 void DSGraph::removeTriviallyDeadNodes() {
930 removeIdenticalCalls(FunctionCalls, Func ? Func->getName() : "");
931 removeIdenticalCalls(AuxFunctionCalls, Func ? Func->getName() : "");
933 for (unsigned i = 0; i != Nodes.size(); ++i)
934 if (isNodeDead(Nodes[i])) { // This node is dead!
935 delete Nodes[i]; // Free memory...
936 Nodes.erase(Nodes.begin()+i--); // Remove from node list...
941 // markAlive - Simple graph walker that recursively traverses the graph, marking
942 // stuff to be alive.
944 static void markAlive(DSNode *N, std::set<DSNode*> &Alive) {
946 std::set<DSNode*>::iterator I = Alive.lower_bound(N);
947 if (I != Alive.end() && *I == N) return; // Already marked alive
948 Alive.insert(I, N); // Is alive now
950 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
951 markAlive(N->getLink(i).getNode(), Alive);
954 // markAliveIfCanReachAlive - Simple graph walker that recursively traverses the
955 // graph looking for a node that is marked alive. If the node is marked alive,
956 // the recursive unwind marks node alive that can point to the alive node. This
957 // is basically just a post-order traversal.
959 // This function returns true if the specified node is alive.
961 static bool markAliveIfCanReachAlive(DSNode *N, std::set<DSNode*> &Alive,
962 std::set<DSNode*> &Visited) {
963 if (N == 0) return false;
965 // If we know that this node is alive, return so!
966 if (Alive.count(N)) return true;
968 // Otherwise, we don't think the node is alive yet, check for infinite
970 std::set<DSNode*>::iterator VI = Visited.lower_bound(N);
971 if (VI != Visited.end() && *VI == N) return false; // Found a cycle
972 // No recursion, insert into Visited...
973 Visited.insert(VI, N);
975 if (N->NodeType & DSNode::GlobalNode)
976 return false; // Global nodes will be marked on their own
978 bool ChildrenAreAlive = false;
980 for (unsigned i = 0, e = N->getSize(); i < e; i += DS::PointerSize)
981 ChildrenAreAlive |= markAliveIfCanReachAlive(N->getLink(i).getNode(),
983 if (ChildrenAreAlive)
985 return ChildrenAreAlive;
988 static bool CallSiteUsesAliveArgs(DSCallSite &CS, std::set<DSNode*> &Alive,
989 std::set<DSNode*> &Visited) {
990 if (markAliveIfCanReachAlive(CS.getRetVal().getNode(), Alive, Visited) ||
991 markAliveIfCanReachAlive(CS.getCallee().getNode(), Alive, Visited))
993 for (unsigned j = 0, e = CS.getNumPtrArgs(); j != e; ++j)
994 if (markAliveIfCanReachAlive(CS.getPtrArg(j).getNode(), Alive, Visited))
999 static void markAlive(DSCallSite &CS, std::set<DSNode*> &Alive) {
1000 markAlive(CS.getRetVal().getNode(), Alive);
1001 markAlive(CS.getCallee().getNode(), Alive);
1003 for (unsigned j = 0, e = CS.getNumPtrArgs(); j != e; ++j)
1004 markAlive(CS.getPtrArg(j).getNode(), Alive);
1007 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
1008 // subgraphs that are unreachable. This often occurs because the data
1009 // structure doesn't "escape" into it's caller, and thus should be eliminated
1010 // from the caller's graph entirely. This is only appropriate to use when
1013 void DSGraph::removeDeadNodes(unsigned Flags) {
1014 // Reduce the amount of work we have to do...
1015 removeTriviallyDeadNodes();
1017 // FIXME: Merge nontrivially identical call nodes...
1019 // Alive - a set that holds all nodes found to be reachable/alive.
1020 std::set<DSNode*> Alive;
1021 std::vector<std::pair<Value*, DSNode*> > GlobalNodes;
1023 // Mark all nodes reachable by (non-global) scalar nodes as alive...
1024 for (std::map<Value*, DSNodeHandle>::iterator I = ScalarMap.begin(),
1025 E = ScalarMap.end(); I != E; ++I)
1026 if (!(Flags & DSGraph::RemoveUnreachableGlobals) ||
1027 !isa<GlobalValue>(I->first)) // Don't mark globals!
1028 markAlive(I->second.getNode(), Alive);
1029 else // Keep track of global nodes
1030 GlobalNodes.push_back(std::make_pair(I->first, I->second.getNode()));
1032 // The return value is alive as well...
1033 markAlive(RetNode.getNode(), Alive);
1035 // If any global nodes points to a non-global that is "alive", the global is
1036 // "alive" as well...
1038 std::set<DSNode*> Visited;
1039 for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
1040 markAliveIfCanReachAlive(GlobalNodes[i].second, Alive, Visited);
1042 std::vector<bool> FCallsAlive(FunctionCalls.size());
1043 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
1044 if (CallSiteUsesAliveArgs(FunctionCalls[i], Alive, Visited)) {
1045 markAlive(FunctionCalls[i], Alive);
1046 FCallsAlive[i] = true;
1049 std::vector<bool> AuxFCallsAlive(AuxFunctionCalls.size());
1050 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
1051 if (CallSiteUsesAliveArgs(AuxFunctionCalls[i], Alive, Visited)) {
1052 markAlive(AuxFunctionCalls[i], Alive);
1053 AuxFCallsAlive[i] = true;
1056 // Remove all dead function calls...
1057 unsigned CurIdx = 0;
1058 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i)
1060 FunctionCalls[CurIdx++].swap(FunctionCalls[i]);
1061 // Crop all the bad ones out...
1062 FunctionCalls.erase(FunctionCalls.begin()+CurIdx, FunctionCalls.end());
1064 // Remove all dead aux function calls...
1066 for (unsigned i = 0, e = AuxFunctionCalls.size(); i != e; ++i)
1067 if (AuxFCallsAlive[i])
1068 AuxFunctionCalls[CurIdx++].swap(AuxFunctionCalls[i]);
1069 // Crop all the bad ones out...
1070 AuxFunctionCalls.erase(AuxFunctionCalls.begin()+CurIdx,
1071 AuxFunctionCalls.end());
1074 // Remove all unreachable globals from the ScalarMap
1075 for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
1076 if (!Alive.count(GlobalNodes[i].second))
1077 ScalarMap.erase(GlobalNodes[i].first);
1079 // Loop over all unreachable nodes, dropping their references...
1080 vector<DSNode*> DeadNodes;
1081 DeadNodes.reserve(Nodes.size()); // Only one allocation is allowed.
1082 for (unsigned i = 0; i != Nodes.size(); ++i)
1083 if (!Alive.count(Nodes[i])) {
1084 DSNode *N = Nodes[i];
1085 Nodes.erase(Nodes.begin()+i--); // Erase node from alive list.
1086 DeadNodes.push_back(N); // Add node to our list of dead nodes
1087 N->dropAllReferences(); // Drop all outgoing edges
1090 // Delete all dead nodes...
1091 std::for_each(DeadNodes.begin(), DeadNodes.end(), deleter<DSNode>);
1095 //===----------------------------------------------------------------------===//
1096 // GlobalDSGraph Implementation
1097 //===----------------------------------------------------------------------===//
1100 // Bits used in the next function
1101 static const char ExternalTypeBits = DSNode::GlobalNode | DSNode::HeapNode;
1104 // GlobalDSGraph::cloneNodeInto - Clone a global node and all its externally
1105 // visible target links (and recursively their such links) into this graph.
1106 // NodeCache maps the node being cloned to its clone in the Globals graph,
1107 // in order to track cycles.
1108 // GlobalsAreFinal is a flag that says whether it is safe to assume that
1109 // an existing global node is complete. This is important to avoid
1110 // reinserting all globals when inserting Calls to functions.
1111 // This is a helper function for cloneGlobals and cloneCalls.
1113 DSNode* GlobalDSGraph::cloneNodeInto(DSNode *OldNode,
1114 std::map<const DSNode*, DSNode*> &NodeCache,
1115 bool GlobalsAreFinal) {
1116 if (OldNode == 0) return 0;
1118 // The caller should check this is an external node. Just more efficient...
1119 assert((OldNode->NodeType & ExternalTypeBits) && "Non-external node");
1121 // If a clone has already been created for OldNode, return it.
1122 DSNode*& CacheEntry = NodeCache[OldNode];
1123 if (CacheEntry != 0)
1126 // The result value...
1127 DSNode* NewNode = 0;
1129 // If nodes already exist for any of the globals of OldNode,
1130 // merge all such nodes together since they are merged in OldNode.
1131 // If ValueCacheIsFinal==true, look for an existing node that has
1132 // an identical list of globals and return it if it exists.
1134 for (unsigned j = 0, N = OldNode->getGlobals().size(); j != N; ++j)
1135 if (DSNode *PrevNode = ScalarMap[OldNode->getGlobals()[j]].getNode()) {
1137 NewNode = PrevNode; // first existing node found
1138 if (GlobalsAreFinal && j == 0)
1139 if (OldNode->getGlobals() == PrevNode->getGlobals()) {
1140 CacheEntry = NewNode;
1144 else if (NewNode != PrevNode) { // found another, different from prev
1145 // update ValMap *before* merging PrevNode into NewNode
1146 for (unsigned k = 0, NK = PrevNode->getGlobals().size(); k < NK; ++k)
1147 ScalarMap[PrevNode->getGlobals()[k]] = NewNode;
1148 NewNode->mergeWith(PrevNode);
1150 } else if (NewNode != 0) {
1151 ScalarMap[OldNode->getGlobals()[j]] = NewNode; // add the merged node
1154 // If no existing node was found, clone the node and update the ValMap.
1156 NewNode = new DSNode(*OldNode);
1157 Nodes.push_back(NewNode);
1158 for (unsigned j = 0, e = NewNode->getNumLinks(); j != e; ++j)
1159 NewNode->setLink(j, 0);
1160 for (unsigned j = 0, N = NewNode->getGlobals().size(); j < N; ++j)
1161 ScalarMap[NewNode->getGlobals()[j]] = NewNode;
1164 NewNode->NodeType |= OldNode->NodeType; // Markers may be different!
1166 // Add the entry to NodeCache
1167 CacheEntry = NewNode;
1169 // Rewrite the links in the new node to point into the current graph,
1170 // but only for links to external nodes. Set other links to NULL.
1171 for (unsigned j = 0, e = OldNode->getNumLinks(); j != e; ++j) {
1172 DSNode* OldTarget = OldNode->getLink(j);
1173 if (OldTarget && (OldTarget->NodeType & ExternalTypeBits)) {
1174 DSNode* NewLink = this->cloneNodeInto(OldTarget, NodeCache);
1175 if (NewNode->getLink(j))
1176 NewNode->getLink(j)->mergeWith(NewLink);
1178 NewNode->setLink(j, NewLink);
1182 // Remove all local markers
1183 NewNode->NodeType &= ~(DSNode::AllocaNode | DSNode::ScalarNode);
1189 // GlobalDSGraph::cloneCalls - Clone function calls and their visible target
1190 // links (and recursively their such links) into this graph.
1192 void GlobalDSGraph::cloneCalls(DSGraph& Graph) {
1193 std::map<const DSNode*, DSNode*> NodeCache;
1194 vector<DSCallSite >& FromCalls =Graph.FunctionCalls;
1196 FunctionCalls.reserve(FunctionCalls.size() + FromCalls.size());
1198 for (int i = 0, ei = FromCalls.size(); i < ei; ++i) {
1199 DSCallSite& callCopy = FunctionCalls.back();
1200 callCopy.reserve(FromCalls[i].size());
1201 for (unsigned j = 0, ej = FromCalls[i].size(); j != ej; ++j)
1203 ((FromCalls[i][j] && (FromCalls[i][j]->NodeType & ExternalTypeBits))
1204 ? cloneNodeInto(FromCalls[i][j], NodeCache, true)
1208 // remove trivially identical function calls
1209 removeIdenticalCalls(FunctionCalls, "Globals Graph");