1 //===- DataStructure.cpp - Implement the core data structure analysis -----===//
3 // This file implements the core data structure functionality.
5 //===----------------------------------------------------------------------===//
7 #include "llvm/Analysis/DSGraph.h"
8 #include "llvm/Function.h"
9 #include "llvm/iOther.h"
10 #include "llvm/DerivedTypes.h"
11 #include "llvm/Target/TargetData.h"
12 #include "Support/STLExtras.h"
13 #include "Support/Statistic.h"
20 namespace DataStructureAnalysis {
21 // isPointerType - Return true if this first class type is big enough to hold
24 bool isPointerType(const Type *Ty);
27 using namespace DataStructureAnalysis;
29 //===----------------------------------------------------------------------===//
30 // DSNode Implementation
31 //===----------------------------------------------------------------------===//
33 DSNode::DSNode(enum NodeTy NT, const Type *T) : NodeType(NT) {
34 // Add the type entry if it is specified...
35 if (T) getTypeRec(T, 0);
38 // DSNode copy constructor... do not copy over the referrers list!
39 DSNode::DSNode(const DSNode &N)
40 : Links(N.Links), MergeMap(N.MergeMap),
41 TypeEntries(N.TypeEntries), Globals(N.Globals), NodeType(N.NodeType) {
44 void DSNode::removeReferrer(DSNodeHandle *H) {
45 // Search backwards, because we depopulate the list from the back for
46 // efficiency (because it's a vector).
47 vector<DSNodeHandle*>::reverse_iterator I =
48 std::find(Referrers.rbegin(), Referrers.rend(), H);
49 assert(I != Referrers.rend() && "Referrer not pointing to node!");
50 Referrers.erase(I.base()-1);
53 // addGlobal - Add an entry for a global value to the Globals list. This also
54 // marks the node with the 'G' flag if it does not already have it.
56 void DSNode::addGlobal(GlobalValue *GV) {
57 // Keep the list sorted.
58 vector<GlobalValue*>::iterator I =
59 std::lower_bound(Globals.begin(), Globals.end(), GV);
61 if (I == Globals.end() || *I != GV) {
62 //assert(GV->getType()->getElementType() == Ty);
63 Globals.insert(I, GV);
64 NodeType |= GlobalNode;
68 /// foldNodeCompletely - If we determine that this node has some funny
69 /// behavior happening to it that we cannot represent, we fold it down to a
70 /// single, completely pessimistic, node. This node is represented as a
71 /// single byte with a single TypeEntry of "void".
73 void DSNode::foldNodeCompletely() {
74 // We are no longer typed at all...
76 TypeEntries.push_back(DSTypeRec(Type::VoidTy, 0));
78 // Loop over all of our referrers, making them point to our one byte of space.
79 for (vector<DSNodeHandle*>::iterator I = Referrers.begin(), E=Referrers.end();
83 // Fold the MergeMap down to a single byte of space...
87 // If we have links, merge all of our outgoing links together...
89 MergeMap[0] = 0; // We now contain an outgoing edge...
90 for (unsigned i = 1, e = Links.size(); i != e; ++i)
91 Links[0].mergeWith(Links[i]);
96 /// isNodeCompletelyFolded - Return true if this node has been completely
97 /// folded down to something that can never be expanded, effectively losing
98 /// all of the field sensitivity that may be present in the node.
100 bool DSNode::isNodeCompletelyFolded() const {
101 return getSize() == 1 && TypeEntries.size() == 1 &&
102 TypeEntries[0].Ty == Type::VoidTy;
107 /// setLink - Set the link at the specified offset to the specified
108 /// NodeHandle, replacing what was there. It is uncommon to use this method,
109 /// instead one of the higher level methods should be used, below.
111 void DSNode::setLink(unsigned i, const DSNodeHandle &NH) {
112 // Create a new entry in the Links vector to hold a new element for offset.
114 signed char NewIdx = Links.size();
115 // Check to see if we allocate more than 128 distinct links for this node.
116 // If so, just merge with the last one. This really shouldn't ever happen,
117 // but it should work regardless of whether it does or not.
120 Links.push_back(NH); // Allocate space: common case
121 } else { // Wrap around? Too many links?
122 NewIdx--; // Merge with whatever happened last
123 assert(NewIdx > 0 && "Should wrap back around");
124 std::cerr << "\n*** DSNode found that requires more than 128 "
125 << "active links at once!\n\n";
128 signed char OldIdx = MergeMap[i];
129 assert (OldIdx < 0 && "Shouldn't contain link!");
131 // Make sure that anything aliasing this field gets updated to point to the
133 rewriteMergeMap(OldIdx, NewIdx);
134 assert(MergeMap[i] == NewIdx && "Field not replaced!");
136 Links[MergeMap[i]] = NH;
140 // addEdgeTo - Add an edge from the current node to the specified node. This
141 // can cause merging of nodes in the graph.
143 void DSNode::addEdgeTo(unsigned Offset, const DSNodeHandle &NH) {
144 assert(Offset < getSize() && "Offset out of range!");
145 if (NH.getNode() == 0) return; // Nothing to do
147 if (DSNodeHandle *ExistingNH = getLink(Offset)) {
148 // Merge the two nodes...
149 ExistingNH->mergeWith(NH);
150 } else { // No merging to perform...
151 setLink(Offset, NH); // Just force a link in there...
155 /// getTypeRec - This method returns the specified type record if it exists.
156 /// If it does not yet exist, the method checks to see whether or not the
157 /// request would result in an untrackable state. If adding it would cause
158 /// untrackable state, we foldNodeCompletely the node and return the void
159 /// record, otherwise we add an new TypeEntry and return it.
161 DSTypeRec &DSNode::getTypeRec(const Type *Ty, unsigned Offset) {
162 // If the node is already collapsed, we can't do anything... bail out early
163 if (isNodeCompletelyFolded()) {
164 assert(TypeEntries.size() == 1 && "Node folded and Entries.size() != 1?");
165 return TypeEntries[0];
168 // First search to see if we already have a record for this...
169 DSTypeRec SearchFor(Ty, Offset);
171 std::vector<DSTypeRec>::iterator I;
172 if (TypeEntries.size() < 5) { // Linear search if we have few entries.
173 I = TypeEntries.begin();
174 while (I != TypeEntries.end() && *I < SearchFor)
177 I = std::lower_bound(TypeEntries.begin(), TypeEntries.end(), SearchFor);
180 // At this point, I either points to the right entry or it points to the entry
181 // we are to insert the new entry in front of...
183 if (I != TypeEntries.end() && *I == SearchFor)
186 // ASSUME that it's okay to add this type entry.
187 // FIXME: This should check to make sure it's ok.
189 // If the data size is different then our current size, try to resize the node
190 unsigned ReqSize = Ty->isSized() ? TD.getTypeSize(Ty) : 0;
191 if (getSize() < ReqSize) {
192 // If we are trying to make it bigger, and we can grow the node, do so.
193 if (growNode(ReqSize)) {
194 assert(isNodeCompletelyFolded() && "Node isn't folded?");
195 return TypeEntries[0];
198 } else if (getSize() > ReqSize) {
199 // If we are trying to make the node smaller, we don't have to do anything.
203 return *TypeEntries.insert(I, SearchFor);
206 /// growNode - Attempt to grow the node to the specified size. This may do one
208 /// 1. Grow the node, return false
209 /// 2. Refuse to grow the node, but maintain a trackable situation, return
211 /// 3. Be unable to track if node was that size, so collapse the node and
214 bool DSNode::growNode(unsigned ReqSize) {
215 unsigned OldSize = getSize();
218 // FIXME: DSNode::growNode() doesn't perform correct safety checks yet!
220 foldNodeCompletely();
224 assert(ReqSize > OldSize && "Not growing node!");
226 // Resize the merge map to have enough space...
227 MergeMap.resize(ReqSize);
229 // Assign unique values to all of the elements of MergeMap
231 // Handle the common case of reasonable size structures...
232 for (unsigned i = OldSize; i != ReqSize; ++i)
233 MergeMap[i] = -1-i; // Assign -1, -2, -3, ...
235 // It's possible that we have something really big here. In this case,
236 // divide the object into chunks until it will fit into 128 elements.
237 unsigned Multiple = ReqSize/128;
239 // It's probably an array, and probably some power of two in size.
240 // Because of this, find the biggest power of two that is bigger than
241 // multiple to use as our real Multiple.
242 unsigned RealMultiple = 2;
243 while (RealMultiple <= Multiple) RealMultiple <<= 1;
245 unsigned RealBound = ReqSize/RealMultiple;
246 assert(RealBound <= 128 && "Math didn't work out right");
248 // Now go through and assign indexes that are between -1 and -128
251 for (unsigned i = OldSize; i != ReqSize; ++i)
252 MergeMap[i] = -1-(i % RealBound); // Assign -1, -2, -3...
257 /// mergeMappedValues - This is the higher level form of rewriteMergeMap. It is
258 /// fully capable of merging links together if neccesary as well as simply
259 /// rewriting the map entries.
261 void DSNode::mergeMappedValues(signed char V1, signed char V2) {
262 assert(V1 != V2 && "Cannot merge two identical mapped values!");
264 if (V1 < 0) { // If there is no outgoing link from V1, merge it with V2
265 if (V2 < 0 && V1 > V2)
266 // If both are not linked, merge to the field closer to 0
267 rewriteMergeMap(V2, V1);
269 rewriteMergeMap(V1, V2);
270 } else if (V2 < 0) { // Is V2 < 0 && V1 >= 0?
271 rewriteMergeMap(V2, V1); // Merge into the one with the link...
272 } else { // Otherwise, links exist at both locations
273 // Merge Links[V1] with Links[V2] so they point to the same place now...
274 Links[V1].mergeWith(Links[V2]);
276 // Merge the V2 link into V1 so that we reduce the overall value of the
277 // links are reduced...
279 if (V2 < V1) std::swap(V1, V2); // Ensure V1 < V2
280 rewriteMergeMap(V2, V1); // After this, V2 is "dead"
282 // Change the user of the last link to use V2 instead
283 if ((unsigned)V2 != Links.size()-1) {
284 rewriteMergeMap(Links.size()-1, V2); // Point to V2 instead of last el...
285 // Make sure V2 points the right DSNode
286 Links[V2] = Links.back();
289 // Reduce the number of distinct outgoing links...
295 // MergeSortedVectors - Efficiently merge a vector into another vector where
296 // duplicates are not allowed and both are sorted. This assumes that 'T's are
297 // efficiently copyable and have sane comparison semantics.
300 void MergeSortedVectors(vector<T> &Dest, const vector<T> &Src) {
301 // By far, the most common cases will be the simple ones. In these cases,
302 // avoid having to allocate a temporary vector...
304 if (Src.empty()) { // Nothing to merge in...
306 } else if (Dest.empty()) { // Just copy the result in...
308 } else if (Src.size() == 1) { // Insert a single element...
310 typename vector<T>::iterator I =
311 std::lower_bound(Dest.begin(), Dest.end(), V);
312 if (I == Dest.end() || *I != Src[0]) // If not already contained...
313 Dest.insert(I, Src[0]);
314 } else if (Dest.size() == 1) {
315 T Tmp = Dest[0]; // Save value in temporary...
316 Dest = Src; // Copy over list...
317 typename vector<T>::iterator I =
318 std::lower_bound(Dest.begin(), Dest.end(),Tmp);
319 if (I == Dest.end() || *I != Src[0]) // If not already contained...
320 Dest.insert(I, Src[0]);
323 // Make a copy to the side of Dest...
326 // Make space for all of the type entries now...
327 Dest.resize(Dest.size()+Src.size());
329 // Merge the two sorted ranges together... into Dest.
330 std::merge(Old.begin(), Old.end(), Src.begin(), Src.end(), Dest.begin());
332 // Now erase any duplicate entries that may have accumulated into the
333 // vectors (because they were in both of the input sets)
334 Dest.erase(std::unique(Dest.begin(), Dest.end()), Dest.end());
339 // mergeWith - Merge this node and the specified node, moving all links to and
340 // from the argument node into the current node, deleting the node argument.
341 // Offset indicates what offset the specified node is to be merged into the
344 // The specified node may be a null pointer (in which case, nothing happens).
346 void DSNode::mergeWith(const DSNodeHandle &NH, unsigned Offset) {
347 DSNode *N = NH.getNode();
348 if (N == 0 || (N == this && NH.getOffset() == Offset))
351 assert(NH.getNode() != this &&
352 "Cannot merge two portions of the same node yet!");
354 // If we are merging a node with a completely folded node, then both nodes are
355 // now completely folded.
357 if (isNodeCompletelyFolded()) {
358 N->foldNodeCompletely();
359 } else if (NH.getNode()->isNodeCompletelyFolded()) {
360 foldNodeCompletely();
364 // If both nodes are not at offset 0, make sure that we are merging the node
365 // at an later offset into the node with the zero offset.
367 if (Offset > NH.getOffset()) {
368 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
370 } else if (Offset == NH.getOffset() && getSize() < N->getSize()) {
371 // If the offsets are the same, merge the smaller node into the bigger node
372 N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
377 std::cerr << "\n\nMerging:\n";
378 N->print(std::cerr, 0);
379 std::cerr << " and:\n";
383 // Now we know that Offset <= NH.Offset, so convert it so our "Offset" (with
384 // respect to NH.Offset) is now zero.
386 unsigned NOffset = NH.getOffset()-Offset;
388 // If our destination node is too small... try to grow it.
389 if (N->getSize()+NOffset > getSize() &&
390 growNode(N->getSize()+NOffset)) {
391 // Catastrophic failure occured and we had to collapse the node. In this
392 // case, collapse the other node as well.
393 N->foldNodeCompletely();
396 unsigned NSize = N->getSize();
398 // Remove all edges pointing at N, causing them to point to 'this' instead.
399 // Make sure to adjust their offset, not just the node pointer.
401 while (!N->Referrers.empty()) {
402 DSNodeHandle &Ref = *N->Referrers.back();
403 Ref = DSNodeHandle(this, NOffset+Ref.getOffset());
406 // We must merge fields in this node due to nodes merged in the source node.
407 // In order to handle this we build a map that converts from the source node's
408 // MergeMap values to our MergeMap values. This map is indexed by the
409 // expression: MergeMap[SMM+SourceNodeSize] so we need to allocate at least
410 // 2*SourceNodeSize elements of space for the mapping. We can do this because
411 // we know that there are at most SourceNodeSize outgoing links in the node
412 // (thus that many positive values) and at most SourceNodeSize distinct fields
413 // (thus that many negative values).
415 std::vector<signed char> MergeMapMap(NSize*2, 127);
417 // Loop through the structures, merging them together...
418 for (unsigned i = 0, e = NSize; i != e; ++i) {
419 // Get what this byte of N maps to...
420 signed char NElement = N->MergeMap[i];
422 // Get what we map this byte to...
423 signed char Element = MergeMap[i+NOffset];
424 // We use 127 as a sentinal and don't check for it's existence yet...
425 assert(Element != 127 && "MergeMapMap doesn't permit 127 values yet!");
427 signed char CurMappedVal = MergeMapMap[NElement+NSize];
428 if (CurMappedVal == 127) { // Haven't seen this NElement yet?
429 MergeMapMap[NElement+NSize] = Element; // Map the two together...
430 } else if (CurMappedVal != Element) {
431 // If we are mapping two different fields together this means that we need
432 // to merge fields in the current node due to merging in the source node.
434 mergeMappedValues(CurMappedVal, Element);
435 MergeMapMap[NElement+NSize] = MergeMap[i+NOffset];
439 // Make all of the outgoing links of N now be outgoing links of this. This
440 // can cause recursive merging!
442 for (unsigned i = 0, e = NSize; i != e; ++i)
443 if (DSNodeHandle *Link = N->getLink(i)) {
444 addEdgeTo(i+NOffset, *Link);
445 N->MergeMap[i] = -1; // Kill outgoing edge
448 // Now that there are no outgoing edges, all of the Links are dead.
451 // Merge the node types
452 NodeType |= N->NodeType;
453 N->NodeType = 0; // N is now a dead node.
455 // Adjust all of the type entries we are merging in by the offset...
457 if (NOffset != 0) { // This case is common enough to optimize for
458 // Offset all of the TypeEntries in N with their new offset
459 for (unsigned i = 0, e = N->TypeEntries.size(); i != e; ++i)
460 N->TypeEntries[i].Offset += NOffset;
463 // ... now add them to the TypeEntries list.
464 MergeSortedVectors(TypeEntries, N->TypeEntries);
465 N->TypeEntries.clear(); // N is dead, no type-entries need exist
467 // Merge the globals list...
468 if (!N->Globals.empty()) {
469 MergeSortedVectors(Globals, N->Globals);
471 // Delete the globals from the old node...
476 //===----------------------------------------------------------------------===//
477 // DSCallSite Implementation
478 //===----------------------------------------------------------------------===//
480 // Define here to avoid including iOther.h and BasicBlock.h in DSGraph.h
481 Function &DSCallSite::getCaller() const {
482 return *Inst->getParent()->getParent();
486 //===----------------------------------------------------------------------===//
487 // DSGraph Implementation
488 //===----------------------------------------------------------------------===//
490 DSGraph::DSGraph(const DSGraph &G) : Func(G.Func) {
491 std::map<const DSNode*, DSNode*> NodeMap;
492 RetNode = cloneInto(G, ValueMap, NodeMap);
495 DSGraph::DSGraph(const DSGraph &G, std::map<const DSNode*, DSNode*> &NodeMap)
497 RetNode = cloneInto(G, ValueMap, NodeMap);
500 DSGraph::~DSGraph() {
501 FunctionCalls.clear();
506 // Drop all intra-node references, so that assertions don't fail...
507 std::for_each(Nodes.begin(), Nodes.end(),
508 std::mem_fun(&DSNode::dropAllReferences));
511 // Delete all of the nodes themselves...
512 std::for_each(Nodes.begin(), Nodes.end(), deleter<DSNode>);
515 // dump - Allow inspection of graph in a debugger.
516 void DSGraph::dump() const { print(std::cerr); }
519 // Helper function used to clone a function list.
521 static void CopyFunctionCallsList(const vector<DSCallSite>& fromCalls,
522 vector<DSCallSite> &toCalls,
523 std::map<const DSNode*, DSNode*> &NodeMap) {
524 unsigned FC = toCalls.size(); // FirstCall
525 toCalls.reserve(FC+fromCalls.size());
526 for (unsigned i = 0, ei = fromCalls.size(); i != ei; ++i)
527 toCalls.push_back(DSCallSite(fromCalls[i], NodeMap));
530 /// remapLinks - Change all of the Links in the current node according to the
531 /// specified mapping.
533 void DSNode::remapLinks(std::map<const DSNode*, DSNode*> &OldNodeMap) {
534 for (unsigned i = 0, e = Links.size(); i != e; ++i)
535 Links[i].setNode(OldNodeMap[Links[i].getNode()]);
539 // cloneInto - Clone the specified DSGraph into the current graph, returning the
540 // Return node of the graph. The translated ValueMap for the old function is
541 // filled into the OldValMap member. If StripLocals is set to true, Scalar and
542 // Alloca markers are removed from the graph, as the graph is being cloned into
543 // a calling function's graph.
545 DSNodeHandle DSGraph::cloneInto(const DSGraph &G,
546 std::map<Value*, DSNodeHandle> &OldValMap,
547 std::map<const DSNode*, DSNode*> &OldNodeMap,
548 bool StripScalars, bool StripAllocas) {
549 assert(OldNodeMap.empty() && "Returned OldNodeMap should be empty!");
551 unsigned FN = Nodes.size(); // First new node...
553 // Duplicate all of the nodes, populating the node map...
554 Nodes.reserve(FN+G.Nodes.size());
555 for (unsigned i = 0, e = G.Nodes.size(); i != e; ++i) {
556 DSNode *Old = G.Nodes[i];
557 DSNode *New = new DSNode(*Old);
558 Nodes.push_back(New);
559 OldNodeMap[Old] = New;
562 // Rewrite the links in the new nodes to point into the current graph now.
563 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
564 Nodes[i]->remapLinks(OldNodeMap);
566 // Remove local markers as specified
567 unsigned char StripBits = (StripScalars ? DSNode::ScalarNode : 0) |
568 (StripAllocas ? DSNode::AllocaNode : 0);
570 for (unsigned i = FN, e = Nodes.size(); i != e; ++i)
571 Nodes[i]->NodeType &= ~StripBits;
573 // Copy the value map... and merge all of the global nodes...
574 for (std::map<Value*, DSNodeHandle>::const_iterator I = G.ValueMap.begin(),
575 E = G.ValueMap.end(); I != E; ++I) {
576 DSNodeHandle &H = OldValMap[I->first];
577 H = DSNodeHandle(OldNodeMap[I->second.getNode()], I->second.getOffset());
579 if (isa<GlobalValue>(I->first)) { // Is this a global?
580 std::map<Value*, DSNodeHandle>::iterator GVI = ValueMap.find(I->first);
581 if (GVI != ValueMap.end()) { // Is the global value in this fun already?
582 GVI->second.mergeWith(H);
584 ValueMap[I->first] = H; // Add global pointer to this graph
588 // Copy the function calls list...
589 CopyFunctionCallsList(G.FunctionCalls, FunctionCalls, OldNodeMap);
592 // Return the returned node pointer...
593 return DSNodeHandle(OldNodeMap[G.RetNode.getNode()], G.RetNode.getOffset());
597 // cloneGlobalInto - Clone the given global node and all its target links
598 // (and all their llinks, recursively).
600 DSNode *DSGraph::cloneGlobalInto(const DSNode *GNode) {
601 if (GNode == 0 || GNode->getGlobals().size() == 0) return 0;
603 // If a clone has already been created for GNode, return it.
604 DSNodeHandle& ValMapEntry = ValueMap[GNode->getGlobals()[0]];
605 if (ValMapEntry != 0)
608 // Clone the node and update the ValMap.
609 DSNode* NewNode = new DSNode(*GNode);
610 ValMapEntry = NewNode; // j=0 case of loop below!
611 Nodes.push_back(NewNode);
612 for (unsigned j = 1, N = NewNode->getGlobals().size(); j < N; ++j)
613 ValueMap[NewNode->getGlobals()[j]] = NewNode;
615 // Rewrite the links in the new node to point into the current graph.
616 for (unsigned j = 0, e = GNode->getNumLinks(); j != e; ++j)
617 NewNode->setLink(j, cloneGlobalInto(GNode->getLink(j)));
624 // markIncompleteNodes - Mark the specified node as having contents that are not
625 // known with the current analysis we have performed. Because a node makes all
626 // of the nodes it can reach imcomplete if the node itself is incomplete, we
627 // must recursively traverse the data structure graph, marking all reachable
628 // nodes as incomplete.
630 static void markIncompleteNode(DSNode *N) {
631 // Stop recursion if no node, or if node already marked...
632 if (N == 0 || (N->NodeType & DSNode::Incomplete)) return;
634 // Actually mark the node
635 N->NodeType |= DSNode::Incomplete;
637 // Recusively process children...
638 for (unsigned i = 0, e = N->getSize(); i != e; ++i)
639 if (DSNodeHandle *DSNH = N->getLink(i))
640 markIncompleteNode(DSNH->getNode());
644 // markIncompleteNodes - Traverse the graph, identifying nodes that may be
645 // modified by other functions that have not been resolved yet. This marks
646 // nodes that are reachable through three sources of "unknownness":
648 // Global Variables, Function Calls, and Incoming Arguments
650 // For any node that may have unknown components (because something outside the
651 // scope of current analysis may have modified it), the 'Incomplete' flag is
652 // added to the NodeType.
654 void DSGraph::markIncompleteNodes(bool markFormalArgs) {
655 // Mark any incoming arguments as incomplete...
656 if (markFormalArgs && Func)
657 for (Function::aiterator I = Func->abegin(), E = Func->aend(); I != E; ++I)
658 if (isPointerType(I->getType()) && ValueMap.find(I) != ValueMap.end()) {
659 DSNodeHandle &INH = ValueMap[I];
660 if (INH.getNode() && INH.hasLink(0))
661 markIncompleteNode(ValueMap[I].getLink(0)->getNode());
664 // Mark stuff passed into functions calls as being incomplete...
665 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
666 DSCallSite &Call = FunctionCalls[i];
667 // Then the return value is certainly incomplete!
668 markIncompleteNode(Call.getRetVal().getNode());
670 // The call does not make the function argument incomplete...
672 // All arguments to the function call are incomplete though!
673 for (unsigned i = 0, e = Call.getNumPtrArgs(); i != e; ++i)
674 markIncompleteNode(Call.getPtrArg(i).getNode());
677 // Mark all of the nodes pointed to by global or cast nodes as incomplete...
678 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
679 if (Nodes[i]->NodeType & DSNode::GlobalNode) {
680 DSNode *N = Nodes[i];
681 for (unsigned i = 0, e = N->getSize(); i != e; ++i)
682 if (DSNodeHandle *DSNH = N->getLink(i))
683 markIncompleteNode(DSNH->getNode());
687 // removeRefsToGlobal - Helper function that removes globals from the
688 // ValueMap so that the referrer count will go down to zero.
689 static void removeRefsToGlobal(DSNode* N,
690 std::map<Value*, DSNodeHandle> &ValueMap) {
691 while (!N->getGlobals().empty()) {
692 GlobalValue *GV = N->getGlobals().back();
693 N->getGlobals().pop_back();
699 // isNodeDead - This method checks to see if a node is dead, and if it isn't, it
700 // checks to see if there are simple transformations that it can do to make it
703 bool DSGraph::isNodeDead(DSNode *N) {
704 // Is it a trivially dead shadow node...
705 if (N->getReferrers().empty() && N->NodeType == 0)
708 // Is it a function node or some other trivially unused global?
709 if (N->NodeType != 0 &&
710 (N->NodeType & ~DSNode::GlobalNode) == 0 &&
712 N->getReferrers().size() == N->getGlobals().size()) {
714 // Remove the globals from the ValueMap, so that the referrer count will go
716 removeRefsToGlobal(N, ValueMap);
717 assert(N->getReferrers().empty() && "Referrers should all be gone now!");
724 static void removeIdenticalCalls(vector<DSCallSite> &Calls,
725 const std::string &where) {
726 // Remove trivially identical function calls
727 unsigned NumFns = Calls.size();
728 std::sort(Calls.begin(), Calls.end());
729 Calls.erase(std::unique(Calls.begin(), Calls.end()),
732 DEBUG(if (NumFns != Calls.size())
733 std::cerr << "Merged " << (NumFns-Calls.size())
734 << " call nodes in " << where << "\n";);
737 // removeTriviallyDeadNodes - After the graph has been constructed, this method
738 // removes all unreachable nodes that are created because they got merged with
739 // other nodes in the graph. These nodes will all be trivially unreachable, so
740 // we don't have to perform any non-trivial analysis here.
742 void DSGraph::removeTriviallyDeadNodes(bool KeepAllGlobals) {
743 for (unsigned i = 0; i != Nodes.size(); ++i)
744 if (!KeepAllGlobals || !(Nodes[i]->NodeType & DSNode::GlobalNode))
745 if (isNodeDead(Nodes[i])) { // This node is dead!
746 delete Nodes[i]; // Free memory...
747 Nodes.erase(Nodes.begin()+i--); // Remove from node list...
750 removeIdenticalCalls(FunctionCalls, Func ? Func->getName() : "");
754 // markAlive - Simple graph walker that recursively traverses the graph, marking
755 // stuff to be alive.
757 static void markAlive(DSNode *N, std::set<DSNode*> &Alive) {
761 for (unsigned i = 0, e = N->getSize(); i != e; ++i)
762 if (DSNodeHandle *DSNH = N->getLink(i))
763 if (!Alive.count(DSNH->getNode()))
764 markAlive(DSNH->getNode(), Alive);
767 static bool checkGlobalAlive(DSNode *N, std::set<DSNode*> &Alive,
768 std::set<DSNode*> &Visiting) {
769 if (N == 0) return false;
771 if (Visiting.count(N)) return false; // terminate recursion on a cycle
774 // If any immediate successor is alive, N is alive
775 for (unsigned i = 0, e = N->getSize(); i != e; ++i)
776 if (DSNodeHandle *DSNH = N->getLink(i))
777 if (Alive.count(DSNH->getNode())) {
782 // Else if any successor reaches a live node, N is alive
783 for (unsigned i = 0, e = N->getSize(); i != e; ++i)
784 if (DSNodeHandle *DSNH = N->getLink(i))
785 if (checkGlobalAlive(DSNH->getNode(), Alive, Visiting)) {
786 Visiting.erase(N); return true;
794 // markGlobalsIteration - Recursive helper function for markGlobalsAlive().
795 // This would be unnecessary if function calls were real nodes! In that case,
796 // the simple iterative loop in the first few lines below suffice.
798 static void markGlobalsIteration(std::set<DSNode*>& GlobalNodes,
799 vector<DSCallSite> &Calls,
800 std::set<DSNode*> &Alive,
803 // Iterate, marking globals or cast nodes alive until no new live nodes
804 // are added to Alive
805 std::set<DSNode*> Visiting; // Used to identify cycles
806 std::set<DSNode*>::iterator I = GlobalNodes.begin(), E = GlobalNodes.end();
807 for (size_t liveCount = 0; liveCount < Alive.size(); ) {
808 liveCount = Alive.size();
810 if (Alive.count(*I) == 0) {
812 if (checkGlobalAlive(*I, Alive, Visiting))
813 markAlive(*I, Alive);
817 // Find function calls with some dead and some live nodes.
818 // Since all call nodes must be live if any one is live, we have to mark
819 // all nodes of the call as live and continue the iteration (via recursion).
821 bool Recurse = false;
822 for (unsigned i = 0, ei = Calls.size(); i < ei; ++i) {
823 bool CallIsDead = true, CallHasDeadArg = false;
824 DSCallSite &CS = Calls[i];
825 for (unsigned j = 0, ej = CS.getNumPtrArgs(); j != ej; ++j)
826 if (DSNode *N = CS.getPtrArg(j).getNode()) {
827 bool ArgIsDead = !Alive.count(N);
828 CallHasDeadArg |= ArgIsDead;
829 CallIsDead &= ArgIsDead;
832 if (DSNode *N = CS.getRetVal().getNode()) {
833 bool RetIsDead = !Alive.count(N);
834 CallHasDeadArg |= RetIsDead;
835 CallIsDead &= RetIsDead;
838 DSNode *N = CS.getCallee().getNode();
839 bool FnIsDead = !Alive.count(N);
840 CallHasDeadArg |= FnIsDead;
841 CallIsDead &= FnIsDead;
843 if (!CallIsDead && CallHasDeadArg) {
844 // Some node in this call is live and another is dead.
845 // Mark all nodes of call as live and iterate once more.
847 for (unsigned j = 0, ej = CS.getNumPtrArgs(); j != ej; ++j)
848 markAlive(CS.getPtrArg(j).getNode(), Alive);
849 markAlive(CS.getRetVal().getNode(), Alive);
850 markAlive(CS.getCallee().getNode(), Alive);
854 markGlobalsIteration(GlobalNodes, Calls, Alive, FilterCalls);
859 // markGlobalsAlive - Mark global nodes and cast nodes alive if they
860 // can reach any other live node. Since this can produce new live nodes,
861 // we use a simple iterative algorithm.
863 static void markGlobalsAlive(DSGraph &G, std::set<DSNode*> &Alive,
865 // Add global and cast nodes to a set so we don't walk all nodes every time
866 std::set<DSNode*> GlobalNodes;
867 for (unsigned i = 0, e = G.getNodes().size(); i != e; ++i)
868 if (G.getNodes()[i]->NodeType & DSNode::GlobalNode)
869 GlobalNodes.insert(G.getNodes()[i]);
871 // Add all call nodes to the same set
872 vector<DSCallSite> &Calls = G.getFunctionCalls();
874 for (unsigned i = 0, e = Calls.size(); i != e; ++i) {
875 for (unsigned j = 0, e = Calls[i].getNumPtrArgs(); j != e; ++j)
876 if (DSNode *N = Calls[i].getPtrArg(j).getNode())
877 GlobalNodes.insert(N);
878 if (DSNode *N = Calls[i].getRetVal().getNode())
879 GlobalNodes.insert(N);
880 if (DSNode *N = Calls[i].getCallee().getNode())
881 GlobalNodes.insert(N);
885 // Iterate and recurse until no new live node are discovered.
886 // This would be a simple iterative loop if function calls were real nodes!
887 markGlobalsIteration(GlobalNodes, Calls, Alive, FilterCalls);
889 // Free up references to dead globals from the ValueMap
890 std::set<DSNode*>::iterator I=GlobalNodes.begin(), E=GlobalNodes.end();
892 if (Alive.count(*I) == 0)
893 removeRefsToGlobal(*I, G.getValueMap());
895 // Delete dead function calls
897 for (int ei = Calls.size(), i = ei-1; i >= 0; --i) {
898 bool CallIsDead = true;
899 for (unsigned j = 0, ej = Calls[i].getNumPtrArgs();
900 CallIsDead && j != ej; ++j)
901 CallIsDead = Alive.count(Calls[i].getPtrArg(j).getNode()) == 0;
903 Calls.erase(Calls.begin() + i); // remove the call entirely
907 // removeDeadNodes - Use a more powerful reachability analysis to eliminate
908 // subgraphs that are unreachable. This often occurs because the data
909 // structure doesn't "escape" into it's caller, and thus should be eliminated
910 // from the caller's graph entirely. This is only appropriate to use when
913 void DSGraph::removeDeadNodes(bool KeepAllGlobals, bool KeepCalls) {
914 assert((!KeepAllGlobals || KeepCalls) &&
915 "KeepAllGlobals without KeepCalls is meaningless");
917 // Reduce the amount of work we have to do...
918 removeTriviallyDeadNodes(KeepAllGlobals);
920 // FIXME: Merge nontrivially identical call nodes...
922 // Alive - a set that holds all nodes found to be reachable/alive.
923 std::set<DSNode*> Alive;
925 // If KeepCalls, mark all nodes reachable by call nodes as alive...
927 for (unsigned i = 0, e = FunctionCalls.size(); i != e; ++i) {
928 for (unsigned j = 0, e = FunctionCalls[i].getNumPtrArgs(); j != e; ++j)
929 markAlive(FunctionCalls[i].getPtrArg(j).getNode(), Alive);
930 markAlive(FunctionCalls[i].getRetVal().getNode(), Alive);
931 markAlive(FunctionCalls[i].getCallee().getNode(), Alive);
935 for (unsigned i = 0, e = OrigFunctionCalls.size(); i != e; ++i)
936 for (unsigned j = 0, e = OrigFunctionCalls[i].size(); j != e; ++j)
937 markAlive(OrigFunctionCalls[i][j].getNode(), Alive);
940 // Mark all nodes reachable by scalar nodes (and global nodes, if
941 // keeping them was specified) as alive...
942 unsigned char keepBits = DSNode::ScalarNode |
943 (KeepAllGlobals ? DSNode::GlobalNode : 0);
944 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
945 if (Nodes[i]->NodeType & keepBits)
946 markAlive(Nodes[i], Alive);
948 // The return value is alive as well...
949 markAlive(RetNode.getNode(), Alive);
951 // Mark all globals or cast nodes that can reach a live node as alive.
952 // This also marks all nodes reachable from such nodes as alive.
953 // Of course, if KeepAllGlobals is specified, they would be live already.
955 markGlobalsAlive(*this, Alive, ! KeepCalls);
957 // Loop over all unreachable nodes, dropping their references...
958 vector<DSNode*> DeadNodes;
959 DeadNodes.reserve(Nodes.size()); // Only one allocation is allowed.
960 for (unsigned i = 0; i != Nodes.size(); ++i)
961 if (!Alive.count(Nodes[i])) {
962 DSNode *N = Nodes[i];
963 Nodes.erase(Nodes.begin()+i--); // Erase node from alive list.
964 DeadNodes.push_back(N); // Add node to our list of dead nodes
965 N->dropAllReferences(); // Drop all outgoing edges
968 // Delete all dead nodes...
969 std::for_each(DeadNodes.begin(), DeadNodes.end(), deleter<DSNode>);
974 // maskNodeTypes - Apply a mask to all of the node types in the graph. This
975 // is useful for clearing out markers like Scalar or Incomplete.
977 void DSGraph::maskNodeTypes(unsigned char Mask) {
978 for (unsigned i = 0, e = Nodes.size(); i != e; ++i)
979 Nodes[i]->NodeType &= Mask;
984 //===----------------------------------------------------------------------===//
985 // GlobalDSGraph Implementation
986 //===----------------------------------------------------------------------===//
988 GlobalDSGraph::GlobalDSGraph() : DSGraph(*(Function*)0, this) {
991 GlobalDSGraph::~GlobalDSGraph() {
992 assert(Referrers.size() == 0 &&
993 "Deleting global graph while references from other graphs exist");
996 void GlobalDSGraph::addReference(const DSGraph* referrer) {
997 if (referrer != this)
998 Referrers.insert(referrer);
1001 void GlobalDSGraph::removeReference(const DSGraph* referrer) {
1002 if (referrer != this) {
1003 assert(Referrers.find(referrer) != Referrers.end() && "This is very bad!");
1004 Referrers.erase(referrer);
1005 if (Referrers.size() == 0)
1010 // Bits used in the next function
1011 static const char ExternalTypeBits = DSNode::GlobalNode | DSNode::NewNode;
1014 // GlobalDSGraph::cloneNodeInto - Clone a global node and all its externally
1015 // visible target links (and recursively their such links) into this graph.
1016 // NodeCache maps the node being cloned to its clone in the Globals graph,
1017 // in order to track cycles.
1018 // GlobalsAreFinal is a flag that says whether it is safe to assume that
1019 // an existing global node is complete. This is important to avoid
1020 // reinserting all globals when inserting Calls to functions.
1021 // This is a helper function for cloneGlobals and cloneCalls.
1023 DSNode* GlobalDSGraph::cloneNodeInto(DSNode *OldNode,
1024 std::map<const DSNode*, DSNode*> &NodeCache,
1025 bool GlobalsAreFinal) {
1026 if (OldNode == 0) return 0;
1028 // The caller should check this is an external node. Just more efficient...
1029 assert((OldNode->NodeType & ExternalTypeBits) && "Non-external node");
1031 // If a clone has already been created for OldNode, return it.
1032 DSNode*& CacheEntry = NodeCache[OldNode];
1033 if (CacheEntry != 0)
1036 // The result value...
1037 DSNode* NewNode = 0;
1039 // If nodes already exist for any of the globals of OldNode,
1040 // merge all such nodes together since they are merged in OldNode.
1041 // If ValueCacheIsFinal==true, look for an existing node that has
1042 // an identical list of globals and return it if it exists.
1044 for (unsigned j = 0, N = OldNode->getGlobals().size(); j != N; ++j)
1045 if (DSNode *PrevNode = ValueMap[OldNode->getGlobals()[j]].getNode()) {
1047 NewNode = PrevNode; // first existing node found
1048 if (GlobalsAreFinal && j == 0)
1049 if (OldNode->getGlobals() == PrevNode->getGlobals()) {
1050 CacheEntry = NewNode;
1054 else if (NewNode != PrevNode) { // found another, different from prev
1055 // update ValMap *before* merging PrevNode into NewNode
1056 for (unsigned k = 0, NK = PrevNode->getGlobals().size(); k < NK; ++k)
1057 ValueMap[PrevNode->getGlobals()[k]] = NewNode;
1058 NewNode->mergeWith(PrevNode);
1060 } else if (NewNode != 0) {
1061 ValueMap[OldNode->getGlobals()[j]] = NewNode; // add the merged node
1064 // If no existing node was found, clone the node and update the ValMap.
1066 NewNode = new DSNode(*OldNode);
1067 Nodes.push_back(NewNode);
1068 for (unsigned j = 0, e = NewNode->getNumLinks(); j != e; ++j)
1069 NewNode->setLink(j, 0);
1070 for (unsigned j = 0, N = NewNode->getGlobals().size(); j < N; ++j)
1071 ValueMap[NewNode->getGlobals()[j]] = NewNode;
1074 NewNode->NodeType |= OldNode->NodeType; // Markers may be different!
1076 // Add the entry to NodeCache
1077 CacheEntry = NewNode;
1079 // Rewrite the links in the new node to point into the current graph,
1080 // but only for links to external nodes. Set other links to NULL.
1081 for (unsigned j = 0, e = OldNode->getNumLinks(); j != e; ++j) {
1082 DSNode* OldTarget = OldNode->getLink(j);
1083 if (OldTarget && (OldTarget->NodeType & ExternalTypeBits)) {
1084 DSNode* NewLink = this->cloneNodeInto(OldTarget, NodeCache);
1085 if (NewNode->getLink(j))
1086 NewNode->getLink(j)->mergeWith(NewLink);
1088 NewNode->setLink(j, NewLink);
1092 // Remove all local markers
1093 NewNode->NodeType &= ~(DSNode::AllocaNode | DSNode::ScalarNode);
1099 // GlobalDSGraph::cloneGlobals - Clone global nodes and all their externally
1100 // visible target links (and recursively their such links) into this graph.
1102 void GlobalDSGraph::cloneGlobals(DSGraph& Graph, bool CloneCalls) {
1103 std::map<const DSNode*, DSNode*> NodeCache;
1105 for (unsigned i = 0, N = Graph.Nodes.size(); i < N; ++i)
1106 if (Graph.Nodes[i]->NodeType & DSNode::GlobalNode)
1107 GlobalsGraph->cloneNodeInto(Graph.Nodes[i], NodeCache, false);
1109 GlobalsGraph->cloneCalls(Graph);
1111 GlobalsGraph->removeDeadNodes(/*KeepAllGlobals*/ true, /*KeepCalls*/ true);
1116 // GlobalDSGraph::cloneCalls - Clone function calls and their visible target
1117 // links (and recursively their such links) into this graph.
1119 void GlobalDSGraph::cloneCalls(DSGraph& Graph) {
1120 std::map<const DSNode*, DSNode*> NodeCache;
1121 vector<DSCallSite >& FromCalls =Graph.FunctionCalls;
1123 FunctionCalls.reserve(FunctionCalls.size() + FromCalls.size());
1125 for (int i = 0, ei = FromCalls.size(); i < ei; ++i) {
1126 DSCallSite& callCopy = FunctionCalls.back();
1127 callCopy.reserve(FromCalls[i].size());
1128 for (unsigned j = 0, ej = FromCalls[i].size(); j != ej; ++j)
1130 ((FromCalls[i][j] && (FromCalls[i][j]->NodeType & ExternalTypeBits))
1131 ? cloneNodeInto(FromCalls[i][j], NodeCache, true)
1135 // remove trivially identical function calls
1136 removeIdenticalCalls(FunctionCalls, "Globals Graph");