1 //===- Local.cpp - Compute a local data structure graph for a function ----===//
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 // Compute the local version of the data structure graph for a function. The
11 // external interface to this file is the DSGraph constructor.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Analysis/DataStructure.h"
16 #include "llvm/Analysis/DSGraph.h"
17 #include "llvm/Constants.h"
18 #include "llvm/DerivedTypes.h"
19 #include "llvm/Instructions.h"
20 #include "llvm/Intrinsics.h"
21 #include "llvm/Support/GetElementPtrTypeIterator.h"
22 #include "llvm/Support/InstVisitor.h"
23 #include "llvm/Target/TargetData.h"
24 #include "Support/CommandLine.h"
25 #include "Support/Debug.h"
26 #include "Support/Timer.h"
28 // FIXME: This should eventually be a FunctionPass that is automatically
29 // aggregated into a Pass.
31 #include "llvm/Module.h"
35 static RegisterAnalysis<LocalDataStructures>
36 X("datastructure", "Local Data Structure Analysis");
39 TrackIntegersAsPointers("dsa-track-integers",
40 cl::desc("If this is set, track integers as potential pointers"));
44 // isPointerType - Return true if this type is big enough to hold a pointer.
45 bool isPointerType(const Type *Ty) {
46 if (isa<PointerType>(Ty))
48 else if (TrackIntegersAsPointers && Ty->isPrimitiveType() &&Ty->isInteger())
49 return Ty->getPrimitiveSize() >= PointerSize;
58 DisableDirectCallOpt("disable-direct-call-dsopt", cl::Hidden,
59 cl::desc("Disable direct call optimization in "
60 "DSGraph construction"));
62 DisableFieldSensitivity("disable-ds-field-sensitivity", cl::Hidden,
63 cl::desc("Disable field sensitivity in DSGraphs"));
65 //===--------------------------------------------------------------------===//
67 //===--------------------------------------------------------------------===//
69 /// This class is the builder class that constructs the local data structure
70 /// graph by performing a single pass over the function in question.
72 class GraphBuilder : InstVisitor<GraphBuilder> {
74 DSNodeHandle *RetNode; // Node that gets returned...
75 DSScalarMap &ScalarMap;
76 std::vector<DSCallSite> *FunctionCalls;
79 GraphBuilder(Function &f, DSGraph &g, DSNodeHandle &retNode,
80 std::vector<DSCallSite> &fc)
81 : G(g), RetNode(&retNode), ScalarMap(G.getScalarMap()),
84 // Create scalar nodes for all pointer arguments...
85 for (Function::aiterator I = f.abegin(), E = f.aend(); I != E; ++I)
86 if (isPointerType(I->getType()))
89 visit(f); // Single pass over the function
92 // GraphBuilder ctor for working on the globals graph
93 GraphBuilder(DSGraph &g)
94 : G(g), RetNode(0), ScalarMap(G.getScalarMap()), FunctionCalls(0) {
97 void mergeInGlobalInitializer(GlobalVariable *GV);
100 // Visitor functions, used to handle each instruction type we encounter...
101 friend class InstVisitor<GraphBuilder>;
102 void visitMallocInst(MallocInst &MI) { handleAlloc(MI, true); }
103 void visitAllocaInst(AllocaInst &AI) { handleAlloc(AI, false); }
104 void handleAlloc(AllocationInst &AI, bool isHeap);
106 void visitPHINode(PHINode &PN);
108 void visitGetElementPtrInst(User &GEP);
109 void visitReturnInst(ReturnInst &RI);
110 void visitLoadInst(LoadInst &LI);
111 void visitStoreInst(StoreInst &SI);
112 void visitCallInst(CallInst &CI);
113 void visitInvokeInst(InvokeInst &II);
114 void visitSetCondInst(SetCondInst &SCI) {} // SetEQ & friends are ignored
115 void visitFreeInst(FreeInst &FI);
116 void visitCastInst(CastInst &CI);
117 void visitInstruction(Instruction &I);
119 void visitCallSite(CallSite CS);
120 void visitVANextInst(VANextInst &I);
121 void visitVAArgInst(VAArgInst &I);
123 void MergeConstantInitIntoNode(DSNodeHandle &NH, Constant *C);
125 // Helper functions used to implement the visitation functions...
127 /// createNode - Create a new DSNode, ensuring that it is properly added to
130 DSNode *createNode(const Type *Ty = 0) {
131 DSNode *N = new DSNode(Ty, &G); // Create the node
132 if (DisableFieldSensitivity) {
133 N->foldNodeCompletely();
134 if (DSNode *FN = N->getForwardNode())
140 /// setDestTo - Set the ScalarMap entry for the specified value to point to
141 /// the specified destination. If the Value already points to a node, make
142 /// sure to merge the two destinations together.
144 void setDestTo(Value &V, const DSNodeHandle &NH);
146 /// getValueDest - Return the DSNode that the actual value points to.
148 DSNodeHandle getValueDest(Value &V);
150 /// getLink - This method is used to return the specified link in the
151 /// specified node if one exists. If a link does not already exist (it's
152 /// null), then we create a new node, link it, then return it.
154 DSNodeHandle &getLink(const DSNodeHandle &Node, unsigned Link = 0);
160 //===----------------------------------------------------------------------===//
161 // DSGraph constructor - Simply use the GraphBuilder to construct the local
163 DSGraph::DSGraph(const TargetData &td, Function &F, DSGraph *GG)
164 : GlobalsGraph(GG), TD(td) {
165 PrintAuxCalls = false;
167 DEBUG(std::cerr << " [Loc] Calculating graph for: " << F.getName() << "\n");
169 // Use the graph builder to construct the local version of the graph
170 GraphBuilder B(F, *this, ReturnNodes[&F], FunctionCalls);
172 Timer::addPeakMemoryMeasurement();
175 // Remove all integral constants from the scalarmap!
176 for (DSScalarMap::iterator I = ScalarMap.begin(); I != ScalarMap.end();)
177 if (isa<ConstantIntegral>(I->first))
178 ScalarMap.erase(I++);
182 // If there are any constant globals referenced in this function, merge their
183 // initializers into the local graph from the globals graph.
184 if (ScalarMap.global_begin() != ScalarMap.global_end()) {
185 ReachabilityCloner RC(*this, *GG, 0);
187 for (DSScalarMap::global_iterator I = ScalarMap.global_begin();
188 I != ScalarMap.global_end(); ++I)
189 if (GlobalVariable *GV = dyn_cast<GlobalVariable>(*I))
190 if (!GV->isExternal() && GV->isConstant())
191 RC.merge(ScalarMap[GV], GG->ScalarMap[GV]);
194 markIncompleteNodes(DSGraph::MarkFormalArgs);
196 // Remove any nodes made dead due to merging...
197 removeDeadNodes(DSGraph::KeepUnreachableGlobals);
201 //===----------------------------------------------------------------------===//
202 // Helper method implementations...
205 /// getValueDest - Return the DSNode that the actual value points to.
207 DSNodeHandle GraphBuilder::getValueDest(Value &Val) {
209 if (V == Constant::getNullValue(V->getType()))
210 return 0; // Null doesn't point to anything, don't add to ScalarMap!
212 DSNodeHandle &NH = ScalarMap[V];
214 return NH; // Already have a node? Just return it...
216 // Otherwise we need to create a new node to point to.
217 // Check first for constant expressions that must be traversed to
218 // extract the actual value.
219 if (Constant *C = dyn_cast<Constant>(V))
220 if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(C)) {
221 return NH = getValueDest(*CPR->getValue());
222 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
223 if (CE->getOpcode() == Instruction::Cast)
224 NH = getValueDest(*CE->getOperand(0));
225 else if (CE->getOpcode() == Instruction::GetElementPtr) {
226 visitGetElementPtrInst(*CE);
227 DSScalarMap::iterator I = ScalarMap.find(CE);
228 assert(I != ScalarMap.end() && "GEP didn't get processed right?");
231 // This returns a conservative unknown node for any unhandled ConstExpr
232 return NH = createNode()->setUnknownNodeMarker();
234 if (NH.getNode() == 0) { // (getelementptr null, X) returns null
240 } else if (ConstantIntegral *CI = dyn_cast<ConstantIntegral>(C)) {
241 // Random constants are unknown mem
242 return NH = createNode()->setUnknownNodeMarker();
244 assert(0 && "Unknown constant type!");
247 // Otherwise we need to create a new node to point to...
249 if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
250 // Create a new global node for this global variable...
251 N = createNode(GV->getType()->getElementType());
254 // Otherwise just create a shadow node
258 NH.setNode(N); // Remember that we are pointing to it...
264 /// getLink - This method is used to return the specified link in the
265 /// specified node if one exists. If a link does not already exist (it's
266 /// null), then we create a new node, link it, then return it. We must
267 /// specify the type of the Node field we are accessing so that we know what
268 /// type should be linked to if we need to create a new node.
270 DSNodeHandle &GraphBuilder::getLink(const DSNodeHandle &node, unsigned LinkNo) {
271 DSNodeHandle &Node = const_cast<DSNodeHandle&>(node);
272 DSNodeHandle &Link = Node.getLink(LinkNo);
273 if (!Link.getNode()) {
274 // If the link hasn't been created yet, make and return a new shadow node
281 /// setDestTo - Set the ScalarMap entry for the specified value to point to the
282 /// specified destination. If the Value already points to a node, make sure to
283 /// merge the two destinations together.
285 void GraphBuilder::setDestTo(Value &V, const DSNodeHandle &NH) {
286 ScalarMap[&V].mergeWith(NH);
290 //===----------------------------------------------------------------------===//
291 // Specific instruction type handler implementations...
294 /// Alloca & Malloc instruction implementation - Simply create a new memory
295 /// object, pointing the scalar to it.
297 void GraphBuilder::handleAlloc(AllocationInst &AI, bool isHeap) {
298 DSNode *N = createNode();
300 N->setHeapNodeMarker();
302 N->setAllocaNodeMarker();
306 // PHINode - Make the scalar for the PHI node point to all of the things the
307 // incoming values point to... which effectively causes them to be merged.
309 void GraphBuilder::visitPHINode(PHINode &PN) {
310 if (!isPointerType(PN.getType())) return; // Only pointer PHIs
312 DSNodeHandle &PNDest = ScalarMap[&PN];
313 for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
314 PNDest.mergeWith(getValueDest(*PN.getIncomingValue(i)));
317 void GraphBuilder::visitGetElementPtrInst(User &GEP) {
318 DSNodeHandle Value = getValueDest(*GEP.getOperand(0));
319 if (Value.getNode() == 0) return;
321 // As a special case, if all of the index operands of GEP are constant zeros,
322 // handle this just like we handle casts (ie, don't do much).
323 bool AllZeros = true;
324 for (unsigned i = 1, e = GEP.getNumOperands(); i != e; ++i)
325 if (GEP.getOperand(i) !=
326 Constant::getNullValue(GEP.getOperand(i)->getType())) {
331 // If all of the indices are zero, the result points to the operand without
332 // applying the type.
334 setDestTo(GEP, Value);
339 const PointerType *PTy = cast<PointerType>(GEP.getOperand(0)->getType());
340 const Type *CurTy = PTy->getElementType();
342 if (Value.getNode()->mergeTypeInfo(CurTy, Value.getOffset())) {
343 // If the node had to be folded... exit quickly
344 setDestTo(GEP, Value); // GEP result points to folded node
348 const TargetData &TD = Value.getNode()->getTargetData();
351 // Handle the pointer index specially...
352 if (GEP.getNumOperands() > 1 &&
353 GEP.getOperand(1) != ConstantSInt::getNullValue(Type::LongTy)) {
355 // If we already know this is an array being accessed, don't do anything...
356 if (!TopTypeRec.isArray) {
357 TopTypeRec.isArray = true;
359 // If we are treating some inner field pointer as an array, fold the node
360 // up because we cannot handle it right. This can come because of
361 // something like this: &((&Pt->X)[1]) == &Pt->Y
363 if (Value.getOffset()) {
364 // Value is now the pointer we want to GEP to be...
365 Value.getNode()->foldNodeCompletely();
366 setDestTo(GEP, Value); // GEP result points to folded node
369 // This is a pointer to the first byte of the node. Make sure that we
370 // are pointing to the outter most type in the node.
371 // FIXME: We need to check one more case here...
377 // All of these subscripts are indexing INTO the elements we have...
379 for (gep_type_iterator I = gep_type_begin(GEP), E = gep_type_end(GEP);
381 if (const StructType *STy = dyn_cast<StructType>(*I)) {
382 unsigned FieldNo = cast<ConstantUInt>(I.getOperand())->getValue();
383 Offset += TD.getStructLayout(STy)->MemberOffsets[FieldNo];
384 } else if (const PointerType *PTy = dyn_cast<PointerType>(*I)) {
385 if (!isa<Constant>(I.getOperand()) ||
386 !cast<Constant>(I.getOperand())->isNullValue())
387 Value.getNode()->setArrayMarker();
392 if (const SequentialType *STy = cast<SequentialType>(*I)) {
393 CurTy = STy->getElementType();
394 if (ConstantSInt *CS = dyn_cast<ConstantSInt>(GEP.getOperand(i))) {
395 Offset += CS->getValue()*TD.getTypeSize(CurTy);
397 // Variable index into a node. We must merge all of the elements of the
398 // sequential type here.
399 if (isa<PointerType>(STy))
400 std::cerr << "Pointer indexing not handled yet!\n";
402 const ArrayType *ATy = cast<ArrayType>(STy);
403 unsigned ElSize = TD.getTypeSize(CurTy);
404 DSNode *N = Value.getNode();
405 assert(N && "Value must have a node!");
406 unsigned RawOffset = Offset+Value.getOffset();
408 // Loop over all of the elements of the array, merging them into the
410 for (unsigned i = 1, e = ATy->getNumElements(); i != e; ++i)
411 // Merge all of the byte components of this array element
412 for (unsigned j = 0; j != ElSize; ++j)
413 N->mergeIndexes(RawOffset+j, RawOffset+i*ElSize+j);
419 // Add in the offset calculated...
420 Value.setOffset(Value.getOffset()+Offset);
422 // Value is now the pointer we want to GEP to be...
423 setDestTo(GEP, Value);
426 void GraphBuilder::visitLoadInst(LoadInst &LI) {
427 DSNodeHandle Ptr = getValueDest(*LI.getOperand(0));
428 if (Ptr.getNode() == 0) return;
430 // Make that the node is read from...
431 Ptr.getNode()->setReadMarker();
433 // Ensure a typerecord exists...
434 Ptr.getNode()->mergeTypeInfo(LI.getType(), Ptr.getOffset(), false);
436 if (isPointerType(LI.getType()))
437 setDestTo(LI, getLink(Ptr));
440 void GraphBuilder::visitStoreInst(StoreInst &SI) {
441 const Type *StoredTy = SI.getOperand(0)->getType();
442 DSNodeHandle Dest = getValueDest(*SI.getOperand(1));
443 if (Dest.isNull()) return;
445 // Mark that the node is written to...
446 Dest.getNode()->setModifiedMarker();
448 // Ensure a type-record exists...
449 Dest.getNode()->mergeTypeInfo(StoredTy, Dest.getOffset());
451 // Avoid adding edges from null, or processing non-"pointer" stores
452 if (isPointerType(StoredTy))
453 Dest.addEdgeTo(getValueDest(*SI.getOperand(0)));
456 void GraphBuilder::visitReturnInst(ReturnInst &RI) {
457 if (RI.getNumOperands() && isPointerType(RI.getOperand(0)->getType()))
458 RetNode->mergeWith(getValueDest(*RI.getOperand(0)));
461 void GraphBuilder::visitVANextInst(VANextInst &I) {
462 getValueDest(*I.getOperand(0)).mergeWith(getValueDest(I));
465 void GraphBuilder::visitVAArgInst(VAArgInst &I) {
466 DSNodeHandle Ptr = getValueDest(*I.getOperand(0));
467 if (Ptr.isNull()) return;
469 // Make that the node is read from.
470 Ptr.getNode()->setReadMarker();
472 // Ensure a typerecord exists...
473 Ptr.getNode()->mergeTypeInfo(I.getType(), Ptr.getOffset(), false);
475 if (isPointerType(I.getType()))
476 setDestTo(I, getLink(Ptr));
480 void GraphBuilder::visitCallInst(CallInst &CI) {
484 void GraphBuilder::visitInvokeInst(InvokeInst &II) {
488 void GraphBuilder::visitCallSite(CallSite CS) {
489 Value *Callee = CS.getCalledValue();
490 if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(Callee))
491 Callee = CPR->getValue();
493 // Special case handling of certain libc allocation functions here.
494 if (Function *F = dyn_cast<Function>(Callee))
496 switch (F->getIntrinsicID()) {
497 case Intrinsic::va_start:
498 getValueDest(*CS.getInstruction()).getNode()->setAllocaNodeMarker();
500 case Intrinsic::va_copy:
501 getValueDest(*CS.getInstruction()).
502 mergeWith(getValueDest(**(CS.arg_begin())));
504 case Intrinsic::va_end:
506 case Intrinsic::memmove:
507 case Intrinsic::memcpy: {
508 // Merge the first & second arguments, and mark the memory read and
510 DSNodeHandle RetNH = getValueDest(**CS.arg_begin());
511 RetNH.mergeWith(getValueDest(**(CS.arg_begin()+1)));
512 if (DSNode *N = RetNH.getNode())
513 N->setModifiedMarker()->setReadMarker();
516 case Intrinsic::memset:
517 // Mark the memory modified.
518 if (DSNode *N = getValueDest(**CS.arg_begin()).getNode())
519 N->setModifiedMarker();
522 if (F->getName() == "calloc") {
523 setDestTo(*CS.getInstruction(),
524 createNode()->setHeapNodeMarker()->setModifiedMarker());
526 } else if (F->getName() == "realloc") {
527 DSNodeHandle RetNH = getValueDest(*CS.getInstruction());
528 RetNH.mergeWith(getValueDest(**CS.arg_begin()));
529 if (DSNode *N = RetNH.getNode())
530 N->setHeapNodeMarker()->setModifiedMarker()->setReadMarker();
532 } else if (F->getName() == "memmove") {
533 // Merge the first & second arguments, and mark the memory read and
535 DSNodeHandle RetNH = getValueDest(**CS.arg_begin());
536 RetNH.mergeWith(getValueDest(**(CS.arg_begin()+1)));
537 if (DSNode *N = RetNH.getNode())
538 N->setModifiedMarker()->setReadMarker();
541 } else if (F->getName() == "atoi" || F->getName() == "atof" ||
542 F->getName() == "atol" || F->getName() == "atoll" ||
543 F->getName() == "remove" || F->getName() == "unlink" ||
544 F->getName() == "rename" || F->getName() == "memcmp" ||
545 F->getName() == "strcmp" || F->getName() == "strncmp" ||
546 F->getName() == "execl" || F->getName() == "execlp" ||
547 F->getName() == "execle" || F->getName() == "execv" ||
548 F->getName() == "execvp" || F->getName() == "chmod" ||
549 F->getName() == "puts" || F->getName() == "write" ||
550 F->getName() == "open" || F->getName() == "create" ||
551 F->getName() == "truncate" || F->getName() == "chdir" ||
552 F->getName() == "mkdir" || F->getName() == "rmdir") {
553 // These functions read all of their pointer operands.
554 for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
556 if (isPointerType((*AI)->getType()))
557 if (DSNode *N = getValueDest(**AI).getNode())
561 } else if (F->getName() == "read" || F->getName() == "pipe" ||
562 F->getName() == "wait" || F->getName() == "time") {
563 // These functions write all of their pointer operands.
564 for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
566 if (isPointerType((*AI)->getType()))
567 if (DSNode *N = getValueDest(**AI).getNode())
568 N->setModifiedMarker();
571 } else if (F->getName() == "stat" || F->getName() == "fstat" ||
572 F->getName() == "lstat") {
573 // These functions read their first operand if its a pointer.
574 CallSite::arg_iterator AI = CS.arg_begin();
575 if (isPointerType((*AI)->getType())) {
576 DSNodeHandle Path = getValueDest(**AI);
577 if (DSNode *N = Path.getNode()) N->setReadMarker();
580 // Then they write into the stat buffer.
581 DSNodeHandle StatBuf = getValueDest(**++AI);
582 if (DSNode *N = StatBuf.getNode()) {
583 N->setModifiedMarker();
584 const Type *StatTy = F->getFunctionType()->getParamType(1);
585 if (const PointerType *PTy = dyn_cast<PointerType>(StatTy))
586 N->mergeTypeInfo(PTy->getElementType(), StatBuf.getOffset());
589 } else if (F->getName() == "fopen" || F->getName() == "fdopen" ||
590 F->getName() == "freopen") {
591 // These functions read all of their pointer operands.
592 for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
594 if (isPointerType((*AI)->getType()))
595 if (DSNode *N = getValueDest(**AI).getNode())
598 // fopen allocates in an unknown way and writes to the file
599 // descriptor. Also, merge the allocated type into the node.
600 DSNodeHandle Result = getValueDest(*CS.getInstruction());
601 if (DSNode *N = Result.getNode()) {
602 N->setModifiedMarker()->setUnknownNodeMarker();
603 const Type *RetTy = F->getFunctionType()->getReturnType();
604 if (const PointerType *PTy = dyn_cast<PointerType>(RetTy))
605 N->mergeTypeInfo(PTy->getElementType(), Result.getOffset());
608 // If this is freopen, merge the file descriptor passed in with the
610 if (F->getName() == "freopen")
611 Result.mergeWith(getValueDest(**--CS.arg_end()));
614 } else if (F->getName() == "fclose" && CS.arg_end()-CS.arg_begin() ==1){
615 // fclose reads and deallocates the memory in an unknown way for the
616 // file descriptor. It merges the FILE type into the descriptor.
617 DSNodeHandle H = getValueDest(**CS.arg_begin());
618 if (DSNode *N = H.getNode()) {
619 N->setReadMarker()->setUnknownNodeMarker();
620 const Type *ArgTy = F->getFunctionType()->getParamType(0);
621 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
622 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
625 } else if (CS.arg_end()-CS.arg_begin() == 1 &&
626 (F->getName() == "fflush" || F->getName() == "feof" ||
627 F->getName() == "fileno" || F->getName() == "clearerr" ||
628 F->getName() == "rewind" || F->getName() == "ftell" ||
629 F->getName() == "ferror" || F->getName() == "fgetc" ||
630 F->getName() == "fgetc" || F->getName() == "_IO_getc")) {
631 // fflush reads and writes the memory for the file descriptor. It
632 // merges the FILE type into the descriptor.
633 DSNodeHandle H = getValueDest(**CS.arg_begin());
634 if (DSNode *N = H.getNode()) {
635 N->setReadMarker()->setModifiedMarker();
637 const Type *ArgTy = F->getFunctionType()->getParamType(0);
638 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
639 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
642 } else if (CS.arg_end()-CS.arg_begin() == 4 &&
643 (F->getName() == "fwrite" || F->getName() == "fread")) {
644 // fread writes the first operand, fwrite reads it. They both
645 // read/write the FILE descriptor, and merges the FILE type.
646 DSNodeHandle H = getValueDest(**--CS.arg_end());
647 if (DSNode *N = H.getNode()) {
648 N->setReadMarker()->setModifiedMarker();
649 const Type *ArgTy = F->getFunctionType()->getParamType(3);
650 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
651 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
654 H = getValueDest(**CS.arg_begin());
655 if (DSNode *N = H.getNode())
656 if (F->getName() == "fwrite")
659 N->setModifiedMarker();
661 } else if (F->getName() == "fgets" && CS.arg_end()-CS.arg_begin() == 3){
662 // fgets reads and writes the memory for the file descriptor. It
663 // merges the FILE type into the descriptor, and writes to the
664 // argument. It returns the argument as well.
665 CallSite::arg_iterator AI = CS.arg_begin();
666 DSNodeHandle H = getValueDest(**AI);
667 if (DSNode *N = H.getNode())
668 N->setModifiedMarker(); // Writes buffer
669 H.mergeWith(getValueDest(*CS.getInstruction())); // Returns buffer
672 // Reads and writes file descriptor, merge in FILE type.
673 H = getValueDest(**AI);
674 if (DSNode *N = H.getNode()) {
675 N->setReadMarker()->setModifiedMarker();
676 const Type *ArgTy = F->getFunctionType()->getParamType(2);
677 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
678 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
681 } else if (F->getName() == "ungetc" || F->getName() == "fputc" ||
682 F->getName() == "fputs" || F->getName() == "putc" ||
683 F->getName() == "ftell" || F->getName() == "rewind" ||
684 F->getName() == "_IO_putc") {
685 // These functions read and write the memory for the file descriptor,
686 // which is passes as the last argument.
687 DSNodeHandle H = getValueDest(**--CS.arg_end());
688 if (DSNode *N = H.getNode()) {
689 N->setReadMarker()->setModifiedMarker();
690 const Type *ArgTy = *--F->getFunctionType()->param_end();
691 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
692 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
695 // Any pointer arguments are read.
696 for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
698 if (isPointerType((*AI)->getType()))
699 if (DSNode *N = getValueDest(**AI).getNode())
702 } else if (F->getName() == "fseek" || F->getName() == "fgetpos" ||
703 F->getName() == "fsetpos") {
704 // These functions read and write the memory for the file descriptor,
705 // and read/write all other arguments.
706 DSNodeHandle H = getValueDest(**CS.arg_begin());
707 if (DSNode *N = H.getNode()) {
708 const Type *ArgTy = *--F->getFunctionType()->param_end();
709 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
710 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
713 // Any pointer arguments are read.
714 for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
716 if (isPointerType((*AI)->getType()))
717 if (DSNode *N = getValueDest(**AI).getNode())
718 N->setReadMarker()->setModifiedMarker();
720 } else if (F->getName() == "printf" || F->getName() == "fprintf" ||
721 F->getName() == "sprintf") {
722 CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
724 if (F->getName() == "fprintf") {
725 // fprintf reads and writes the FILE argument, and applies the type
727 DSNodeHandle H = getValueDest(**AI);
728 if (DSNode *N = H.getNode()) {
729 N->setModifiedMarker();
730 const Type *ArgTy = (*AI)->getType();
731 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
732 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
734 } else if (F->getName() == "sprintf") {
735 // sprintf writes the first string argument.
736 DSNodeHandle H = getValueDest(**AI++);
737 if (DSNode *N = H.getNode()) {
738 N->setModifiedMarker();
739 const Type *ArgTy = (*AI)->getType();
740 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
741 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
745 for (; AI != E; ++AI) {
746 // printf reads all pointer arguments.
747 if (isPointerType((*AI)->getType()))
748 if (DSNode *N = getValueDest(**AI).getNode())
752 } else if (F->getName() == "scanf" || F->getName() == "fscanf" ||
753 F->getName() == "sscanf") {
754 CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
756 if (F->getName() == "fscanf") {
757 // fscanf reads and writes the FILE argument, and applies the type
759 DSNodeHandle H = getValueDest(**AI);
760 if (DSNode *N = H.getNode()) {
762 const Type *ArgTy = (*AI)->getType();
763 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
764 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
766 } else if (F->getName() == "sscanf") {
767 // sscanf reads the first string argument.
768 DSNodeHandle H = getValueDest(**AI++);
769 if (DSNode *N = H.getNode()) {
771 const Type *ArgTy = (*AI)->getType();
772 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
773 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
777 for (; AI != E; ++AI) {
778 // scanf writes all pointer arguments.
779 if (isPointerType((*AI)->getType()))
780 if (DSNode *N = getValueDest(**AI).getNode())
781 N->setModifiedMarker();
784 } else if (F->getName() == "strtok") {
785 // strtok reads and writes the first argument, returning it. It reads
786 // its second arg. FIXME: strtok also modifies some hidden static
787 // data. Someday this might matter.
788 CallSite::arg_iterator AI = CS.arg_begin();
789 DSNodeHandle H = getValueDest(**AI++);
790 if (DSNode *N = H.getNode()) {
791 N->setReadMarker()->setModifiedMarker(); // Reads/Writes buffer
792 const Type *ArgTy = F->getFunctionType()->getParamType(0);
793 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
794 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
796 H.mergeWith(getValueDest(*CS.getInstruction())); // Returns buffer
798 H = getValueDest(**AI); // Reads delimiter
799 if (DSNode *N = H.getNode()) {
801 const Type *ArgTy = F->getFunctionType()->getParamType(1);
802 if (const PointerType *PTy = dyn_cast<PointerType>(ArgTy))
803 N->mergeTypeInfo(PTy->getElementType(), H.getOffset());
806 } else if (F->getName() == "strchr" || F->getName() == "strrchr" ||
807 F->getName() == "strstr") {
808 // These read their arguments, and return the first one
809 DSNodeHandle H = getValueDest(**CS.arg_begin());
810 H.mergeWith(getValueDest(*CS.getInstruction())); // Returns buffer
812 for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end();
814 if (isPointerType((*AI)->getType()))
815 if (DSNode *N = getValueDest(**AI).getNode())
818 if (DSNode *N = H.getNode())
821 } else if (F->getName() == "modf" && CS.arg_end()-CS.arg_begin() == 2) {
822 // This writes its second argument, and forces it to double.
823 DSNodeHandle H = getValueDest(**--CS.arg_end());
824 if (DSNode *N = H.getNode()) {
825 N->setModifiedMarker();
826 N->mergeTypeInfo(Type::DoubleTy, H.getOffset());
830 // Unknown function, warn if it returns a pointer type or takes a
832 bool Warn = isPointerType(CS.getInstruction()->getType());
834 for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
836 if (isPointerType((*I)->getType())) {
841 std::cerr << "WARNING: Call to unknown external function '"
842 << F->getName() << "' will cause pessimistic results!\n";
847 // Set up the return value...
849 Instruction *I = CS.getInstruction();
850 if (isPointerType(I->getType()))
851 RetVal = getValueDest(*I);
853 DSNode *CalleeNode = 0;
854 if (DisableDirectCallOpt || !isa<Function>(Callee)) {
855 CalleeNode = getValueDest(*Callee).getNode();
856 if (CalleeNode == 0) {
857 std::cerr << "WARNING: Program is calling through a null pointer?\n"<< *I;
858 return; // Calling a null pointer?
862 std::vector<DSNodeHandle> Args;
863 Args.reserve(CS.arg_end()-CS.arg_begin());
865 // Calculate the arguments vector...
866 for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); I != E; ++I)
867 if (isPointerType((*I)->getType()))
868 Args.push_back(getValueDest(**I));
870 // Add a new function call entry...
872 FunctionCalls->push_back(DSCallSite(CS, RetVal, CalleeNode, Args));
874 FunctionCalls->push_back(DSCallSite(CS, RetVal, cast<Function>(Callee),
878 void GraphBuilder::visitFreeInst(FreeInst &FI) {
879 // Mark that the node is written to...
880 if (DSNode *N = getValueDest(*FI.getOperand(0)).getNode())
881 N->setModifiedMarker()->setHeapNodeMarker();
885 void GraphBuilder::visitCastInst(CastInst &CI) {
886 if (isPointerType(CI.getType()))
887 if (isPointerType(CI.getOperand(0)->getType())) {
888 // Cast one pointer to the other, just act like a copy instruction
889 setDestTo(CI, getValueDest(*CI.getOperand(0)));
891 // Cast something (floating point, small integer) to a pointer. We need
892 // to track the fact that the node points to SOMETHING, just something we
893 // don't know about. Make an "Unknown" node.
895 setDestTo(CI, createNode()->setUnknownNodeMarker());
900 // visitInstruction - For all other instruction types, if we have any arguments
901 // that are of pointer type, make them have unknown composition bits, and merge
902 // the nodes together.
903 void GraphBuilder::visitInstruction(Instruction &Inst) {
904 DSNodeHandle CurNode;
905 if (isPointerType(Inst.getType()))
906 CurNode = getValueDest(Inst);
907 for (User::op_iterator I = Inst.op_begin(), E = Inst.op_end(); I != E; ++I)
908 if (isPointerType((*I)->getType()))
909 CurNode.mergeWith(getValueDest(**I));
911 if (CurNode.getNode())
912 CurNode.getNode()->setUnknownNodeMarker();
917 //===----------------------------------------------------------------------===//
918 // LocalDataStructures Implementation
919 //===----------------------------------------------------------------------===//
921 // MergeConstantInitIntoNode - Merge the specified constant into the node
923 void GraphBuilder::MergeConstantInitIntoNode(DSNodeHandle &NH, Constant *C) {
924 // Ensure a type-record exists...
925 NH.getNode()->mergeTypeInfo(C->getType(), NH.getOffset());
927 if (C->getType()->isFirstClassType()) {
928 if (isPointerType(C->getType()))
929 // Avoid adding edges from null, or processing non-"pointer" stores
930 NH.addEdgeTo(getValueDest(*C));
934 const TargetData &TD = NH.getNode()->getTargetData();
936 if (ConstantArray *CA = dyn_cast<ConstantArray>(C)) {
937 for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
938 // We don't currently do any indexing for arrays...
939 MergeConstantInitIntoNode(NH, cast<Constant>(CA->getOperand(i)));
940 } else if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C)) {
941 const StructLayout *SL = TD.getStructLayout(CS->getType());
942 for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
943 DSNodeHandle NewNH(NH.getNode(), NH.getOffset()+SL->MemberOffsets[i]);
944 MergeConstantInitIntoNode(NewNH, cast<Constant>(CS->getOperand(i)));
946 } else if (ConstantAggregateZero *CAZ = dyn_cast<ConstantAggregateZero>(C)) {
949 assert(0 && "Unknown constant type!");
953 void GraphBuilder::mergeInGlobalInitializer(GlobalVariable *GV) {
954 assert(!GV->isExternal() && "Cannot merge in external global!");
955 // Get a node handle to the global node and merge the initializer into it.
956 DSNodeHandle NH = getValueDest(*GV);
957 MergeConstantInitIntoNode(NH, GV->getInitializer());
961 bool LocalDataStructures::run(Module &M) {
962 GlobalsGraph = new DSGraph(getAnalysis<TargetData>());
964 const TargetData &TD = getAnalysis<TargetData>();
967 GraphBuilder GGB(*GlobalsGraph);
969 // Add initializers for all of the globals to the globals graph...
970 for (Module::giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
971 if (!I->isExternal())
972 GGB.mergeInGlobalInitializer(I);
975 // Calculate all of the graphs...
976 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
977 if (!I->isExternal())
978 DSInfo.insert(std::make_pair(I, new DSGraph(TD, *I, GlobalsGraph)));
980 GlobalsGraph->removeTriviallyDeadNodes();
981 GlobalsGraph->markIncompleteNodes(DSGraph::MarkFormalArgs);
985 // releaseMemory - If the pass pipeline is done with this pass, we can release
986 // our memory... here...
988 void LocalDataStructures::releaseMemory() {
989 for (hash_map<Function*, DSGraph*>::iterator I = DSInfo.begin(),
990 E = DSInfo.end(); I != E; ++I) {
991 I->second->getReturnNodes().erase(I->first);
992 if (I->second->getReturnNodes().empty())
996 // Empty map so next time memory is released, data structures are not