예제 #1
0
void RTAssociate::ProcessFunctionBody(Function &F, Function &NewF, DSGraph* G,
                                      DataStructures* DS) {
  if (G->node_begin() == G->node_end()) return; // Quick exit if nothing to do.

  FuncInfo &FI = *getFuncInfo(&F);

  // Calculate which DSNodes are reachable from globals.  If a node is reachable
  // from a global, we will create a global pool for it, so no argument passage
  // is required.

  G->getGlobalsGraph();

  // Map all node reachable from this global to the corresponding nodes in
  // the globals graph.
  DSGraph::NodeMapTy GlobalsGraphNodeMapping;
  G->computeGToGGMapping(GlobalsGraphNodeMapping);

  // Loop over all of the nodes which are non-escaping, adding pool-allocatable
  // ones to the NodesToPA vector.
  for (DSGraph::node_iterator I = G->node_begin(), E = G->node_end(); I != E; ++I) {
    DSNode *N = I;
    if (GlobalsGraphNodeMapping.count(N)) {
      // If it is a global pool, set up the pool descriptor appropriately.
      DSNode *GGN = GlobalsGraphNodeMapping[N].getNode();
      assert(getFuncInfo(0)->PoolDescriptors[GGN] && "Should be in global mapping!");
      FI.PoolDescriptors[N] = getFuncInfo(0)->PoolDescriptors[GGN];
    } else if (!FI.PoolDescriptors[N]) {
      // Otherwise, if it was not passed in from outside the function, it must
      // be a local pool!
      assert(!N->isGlobalNode() && "Should be in global mapping!");
      FI.PoolDescriptors[N] = CreateLocalPool(N, NewF);
    }
  }
  TransformBody(NewF, FI, DS);
}
예제 #2
0
//
// Method: visitCallSite()
//
// Description:
//  This method transforms a call site.  A call site may either be a call
//  instruction or an invoke instruction.
//
// Inputs:
//  CS - The call site representing the instruction that should be transformed.
//
void FuncTransform::visitCallSite(CallSite& CS) {
  const Function *CF = CS.getCalledFunction();
  Instruction *TheCall = CS.getInstruction();
  bool thread_creation_point = false;

  //
  // Get the value that is called at this call site.  Strip away any pointer
  // casts that do not change the representation of the data (i.e., are
  // lossless casts).
  //
  Value * CalledValue = CS.getCalledValue()->stripPointerCasts();

  //
  // The CallSite::getCalledFunction() method is not guaranteed to strip off
  // pointer casts.  If no called function was found, manually strip pointer
  // casts off of the called value and see if we get a function.  If so, this
  // is a direct call, and we want to update CF accordingly.
  //
  if (!CF) CF = dyn_cast<Function>(CalledValue);

  //
  // Do not change any inline assembly code.
  //
  if (isa<InlineAsm>(TheCall->getOperand(0))) {
    errs() << "INLINE ASM: ignoring.  Hoping that's safe.\n";
    return;
  }

  //
  // Ignore calls to NULL pointers or undefined values.
  //
  if ((isa<ConstantPointerNull>(CalledValue)) ||
      (isa<UndefValue>(CalledValue))) {
    errs() << "WARNING: Ignoring call using NULL/Undef function pointer.\n";
    return;
  }

  // If this function is one of the memory manipulating functions built into
  // libc, emulate it with pool calls as appropriate.
  if (CF && CF->isDeclaration()) {
    std::string Name = CF->getName();

    if (Name == "free" || Name == "cfree") {
      visitFreeCall(CS);
      return;
    } else if (Name == "malloc") {
      visitMallocCall(CS);
      return;
    } else if (Name == "calloc") {
      visitCallocCall(CS);
      return;
    } else if (Name == "realloc") {
      visitReallocCall(CS);
      return;
    } else if (Name == "memalign" || Name == "posix_memalign") {
      visitMemAlignCall(CS);
      return;
    } else if (Name == "strdup") {
      visitStrdupCall(CS);
      return;
    } else if (Name == "valloc") {
      errs() << "VALLOC USED BUT NOT HANDLED!\n";
      abort();
    } else if (unsigned PoolArgc = PAInfo.getNumInitialPoolArguments(Name)) {
      visitRuntimeCheck(CS, PoolArgc);
      return;
    } else if (Name == "pthread_create") {
      thread_creation_point = true;

      //
      // Get DSNode representing the DSNode of the function pointer Value of
      // the pthread_create call
      //
      DSNode* thread_callee_node = G->getNodeForValue(CS.getArgument(2)).getNode();
      if (!thread_callee_node) {
    	  assert(0 && "apparently you need this code");
    	  FuncInfo *CFI = PAInfo.getFuncInfo(*CF);
    	  thread_callee_node = G->getNodeForValue(CFI->MapValueToOriginal(CS.getArgument(2))).getNode();
      }

      // Fill in CF with the name of one of the functions in thread_callee_node
      CF = const_cast<Function*>(dyn_cast<Function>(*thread_callee_node->globals_begin()));
    }
  }

  //
  // We need to figure out which local pool descriptors correspond to the pool
  // descriptor arguments passed into the function call.  Calculate a mapping
  // from callee DSNodes to caller DSNodes.  We construct a partial isomophism
  // between the graphs to figure out which pool descriptors need to be passed
  // in.  The roots of this mapping is found from arguments and return values.
  //
  DataStructures& Graphs = PAInfo.getGraphs();
  DSGraph::NodeMapTy NodeMapping;
  Instruction *NewCall;
  Value *NewCallee;
  std::vector<const DSNode*> ArgNodes;
  DSGraph *CalleeGraph;  // The callee graph

  // For indirect callees, find any callee since all DS graphs have been
  // merged.
  if (CF) {   // Direct calls are nice and simple.
    DEBUG(errs() << "  Handling direct call: " << *TheCall << "\n");

    //
    // Do not try to add pool handles to the function if it:
    //  a) Already calls a cloned function; or
    //  b) Calls a function which was never cloned.
    //
    // For such a call, just replace any arguments that take original functions
    // with their cloned function poiner values.
    //
    FuncInfo *CFI = PAInfo.getFuncInfo(*CF);
    if (CFI == 0 || CFI->Clone == 0) {   // Nothing to transform...
      visitInstruction(*TheCall);
      return;
    }

    //
    // Oh, dear.  We must add pool descriptors to this direct call.
    //
    NewCallee = CFI->Clone;
    ArgNodes = CFI->ArgNodes;
    
    assert ((Graphs.hasDSGraph (*CF)) && "Function has no ECGraph!\n");
    CalleeGraph = Graphs.getDSGraph(*CF);
  } else {
    DEBUG(errs() << "  Handling indirect call: " << *TheCall << "\n");
    DSGraph *G =  Graphs.getGlobalsGraph();
    DSGraph::ScalarMapTy& SM = G->getScalarMap();

    // Here we fill in CF with one of the possible called functions.  Because we
    // merged together all of the arguments to all of the functions in the
    // equivalence set, it doesn't really matter which one we pick.
    // (If the function was cloned, we have to map the cloned call instruction
    // in CS back to the original call instruction.)
    Instruction *OrigInst =
      cast<Instruction>(getOldValueIfAvailable(CS.getInstruction()));

    //
    // Attempt to get one of the function targets of this indirect call site by
    // looking at the call graph constructed by the points-to analysis.  Be
    // sure to use the original call site from the original function; the
    // points-to analysis has no information on the clones we've created.
    //
    // Also, look for the target that has the greatest number of arguments that
    // have associated DSNodes.  This ensures that we pass the maximum number
    // of pools possible and prevents us from eliding a pool because we're
    // examining a target that doesn't need it.
    //
    const DSCallGraph & callGraph = Graphs.getCallGraph();

    DSCallGraph::callee_iterator I = callGraph.callee_begin(OrigInst);
    for (; I != callGraph.callee_end(OrigInst); ++I) {
      for(DSCallGraph::scc_iterator sccii = callGraph.scc_begin(*I),
                           sccee = callGraph.scc_end(*I); sccii != sccee; ++sccii){
        if(SM.find(SM.getLeaderForGlobal(*sccii)) == SM.end())
          continue;
        //
        // Get the information for this function.  Since this is coming from
        // DSA, it should be an original function.
        //
        // This call site calls a function, that is not defined in this module
        if (!(Graphs.hasDSGraph(**sccii))) return;

        // For all other cases Func Info must exist.
        PAInfo.getFuncInfo(**sccii);

        //
        // If this target takes more DSNodes than the last one we found, then
        // make *this* target our canonical target.
        //
        CF = *sccii;
        break;
      }
    }
    if(!CF){
    const Function *F1 = OrigInst->getParent()->getParent();
    F1 = callGraph.sccLeader(&*F1);

    for(DSCallGraph::scc_iterator sccii = callGraph.scc_begin(F1),
                           sccee = callGraph.scc_end(F1); sccii != sccee; ++sccii){
        if(SM.find(SM.getLeaderForGlobal(*sccii)) == SM.end())
          continue;
        //
        // Get the information for this function.  Since this is coming from DSA,
        // it should be an original function.
        //
        // This call site calls a function, that is not defined in this module
        if (!(Graphs.hasDSGraph(**sccii))) return;
        // For all other cases Func Info must exist.
        PAInfo.getFuncInfo(**sccii);

        //
        // If this target takes more DSNodes than the last one we found, then
        // make *this* target our canonical target.
        //
        CF = *sccii;
      }
    }
    
    // Assuming the call graph is always correct. And if the call graph reports,
    // no callees, we can assume that it is right.
    //
    // If we didn't find the callee in the constructed call graph, try
    // checking in the DSNode itself.
    // This isn't ideal as it means that this call site didn't have inlining
    // happen.
    //

    //
    // If we still haven't been able to find a target function of the call site
    // to transform, do nothing.
    //
    // One may be tempted to think that we should always have at least one
    // target, but this is not true.  There are perfectly acceptable (but
    // strange) programs for which no function targets exist.  Function
    // pointers loaded from undef values, for example, will have no targets.
    //
    if (!CF) return;

    //
    // It's possible that this program has indirect call targets that are
    // not defined in this module.  Do not transformation for such functions.
    //
    if (!(Graphs.hasDSGraph(*CF))) return;

    //
    // Get the common graph for the set of functions this call may invoke.
    //
    assert ((Graphs.hasDSGraph(*CF)) && "Function has no DSGraph!\n");
    CalleeGraph = Graphs.getDSGraph(*CF);

#ifndef NDEBUG
    // Verify that all potential callees at call site have the same DS graph.
    DSCallGraph::callee_iterator E = Graphs.getCallGraph().callee_end(OrigInst);
    for (; I != E; ++I) {
      const Function * F = *I;
      assert (F);
      if (!(F)->isDeclaration())
        assert(CalleeGraph == Graphs.getDSGraph(**I) &&
               "Callees at call site do not have a common graph!");
    }
#endif    

    // Find the DS nodes for the arguments that need to be added, if any.
    FuncInfo *CFI = PAInfo.getFuncInfo(*CF);
    assert(CFI && "No function info for callee at indirect call?");
    ArgNodes = CFI->ArgNodes;

    if (ArgNodes.empty())
      return;           // No arguments to add?  Transformation is a noop!

    // Cast the function pointer to an appropriate type!
    std::vector<Type*> ArgTys(ArgNodes.size(),
                                    PoolAllocate::PoolDescPtrTy);
    for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
         I != E; ++I)
      ArgTys.push_back((*I)->getType());
    
    FunctionType *FTy = FunctionType::get(TheCall->getType(), ArgTys, false);
    PointerType *PFTy = PointerType::getUnqual(FTy);
    
    // If there are any pool arguments cast the func ptr to the right type.
    NewCallee = CastInst::CreatePointerCast(CS.getCalledValue(), PFTy, "tmp", TheCall);
  }

  //
  // FIXME: Why do we disable strict checking when calling the
  //        DSGraph::computeNodeMapping() method?
  //
  Function::const_arg_iterator FAI = CF->arg_begin(), E = CF->arg_end();
  CallSite::arg_iterator AI = CS.arg_begin() + (thread_creation_point ? 3 : 0);
  CallSite::arg_iterator AE = CS.arg_end();
  for ( ; FAI != E && AI != AE; ++FAI, ++AI)
    if (!isa<Constant>(*AI)) {
      DSGraph::computeNodeMapping(CalleeGraph->getNodeForValue(FAI),
                                  getDSNodeHFor(*AI), NodeMapping, false);
    }

  //assert(AI == AE && "Varargs calls not handled yet!");

  // Map the return value as well...
  if (isa<PointerType>(TheCall->getType()))
    DSGraph::computeNodeMapping(CalleeGraph->getReturnNodeFor(*CF),
                                getDSNodeHFor(TheCall), NodeMapping, false);

  // This code seems redundant (and crashes occasionally)
  // There is no reason to map globals here, since they are not passed as
  // arguments

//   // Map the nodes that are pointed to by globals.
//    DSScalarMap &CalleeSM = CalleeGraph->getScalarMap();
//    for (DSScalarMap::global_iterator GI = G.getScalarMap().global_begin(), 
//           E = G.getScalarMap().global_end(); GI != E; ++GI)
//      if (CalleeSM.count(*GI))
//        DSGraph::computeNodeMapping(CalleeGraph->getNodeForValue(*GI),
//                                    getDSNodeHFor(*GI),
//                                    NodeMapping, false);

  //
  // Okay, now that we have established our mapping, we can figure out which
  // pool descriptors to pass in...
  //
  // Note:
  // There used to be code here that would create a new pool before the
  // function call and destroy it after the function call.  This could would
  // get triggered if bounds checking was disbled or the DSNode for the
  // argument was an array value.
  //
  // I believe that code was incorrect; an argument may have a NULL pool handle
  // (i.e., no pool handle) because the pool allocation heuristic used simply
  // decided not to assign that value a pool.  The argument may alias data
  // that should not be freed after the function call is complete, so calling
  // pooldestroy() after the call would free data, causing dangling pointer
  // dereference errors.
  //
  std::vector<Value*> Args;
  for (unsigned i = 0, e = ArgNodes.size(); i != e; ++i) {
    Value *ArgVal = Constant::getNullValue(PoolAllocate::PoolDescPtrTy);
    if (NodeMapping.count(ArgNodes[i])) {
      if (DSNode *LocalNode = NodeMapping[ArgNodes[i]].getNode())
        if (FI.PoolDescriptors.count(LocalNode))
          ArgVal = FI.PoolDescriptors.find(LocalNode)->second;
    }
    Args.push_back(ArgVal);
  }

  // Add the rest of the arguments unless we're a thread creation point, in which case we only need the pools
  if(!thread_creation_point)
	  Args.insert(Args.end(), CS.arg_begin(), CS.arg_end());
    
  //
  // There are circumstances where a function is casted to another type and
  // then called (que horible).  We need to perform a similar cast if the
  // type doesn't match the number of arguments.
  //
  if (Function * NewFunction = dyn_cast<Function>(NewCallee)) {
    FunctionType * NewCalleeType = NewFunction->getFunctionType();
    if (NewCalleeType->getNumParams() != Args.size()) {
      std::vector<Type *> Types;
      Type * FuncTy = FunctionType::get (NewCalleeType->getReturnType(),
                                         Types,
                                         true);
      FuncTy = PointerType::getUnqual (FuncTy);
      NewCallee = new BitCastInst (NewCallee, FuncTy, "", TheCall);
    }
  }

  std::string Name = TheCall->getName();    TheCall->setName("");

  if(thread_creation_point) {
	Module *M = CS.getInstruction()->getParent()->getParent()->getParent();
	Value* pthread_replacement = M->getFunction("poolalloc_pthread_create");
	std::vector<Value*> thread_args;

	//Push back original thread arguments through the callee
	thread_args.push_back(CS.getArgument(0));
	thread_args.push_back(CS.getArgument(1));
	thread_args.push_back(CS.getArgument(2));

	//Push back the integer argument saying how many uses there are
	thread_args.push_back(Constant::getIntegerValue(llvm::Type::getInt32Ty(M->getContext()),APInt(32,Args.size())));
	thread_args.insert(thread_args.end(),Args.begin(),Args.end());
	thread_args.push_back(CS.getArgument(3));

	//Make the thread creation call
	NewCall = CallInst::Create(pthread_replacement,
							   thread_args,
							   Name,TheCall);
  }
  else if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
    NewCall = InvokeInst::Create (NewCallee, II->getNormalDest(),
                                  II->getUnwindDest(),
                                  Args, Name, TheCall);
  } else {
    NewCall = CallInst::Create (NewCallee, Args, Name,
                                TheCall);
  }

  // Add all of the uses of the pool descriptor
  for (unsigned i = 0, e = ArgNodes.size(); i != e; ++i)
    AddPoolUse(*NewCall, Args[i], PoolUses);

  TheCall->replaceAllUsesWith(NewCall);
  DEBUG(errs() << "  Result Call: " << *NewCall << "\n");

  if (!TheCall->getType()->isVoidTy()) {
    // If we are modifying the original function, update the DSGraph... 
    DSGraph::ScalarMapTy &SM = G->getScalarMap();
    DSGraph::ScalarMapTy::iterator CII = SM.find(TheCall);
    if (CII != SM.end()) {
      SM[NewCall] = CII->second;
      SM.erase(CII);                     // Destroy the CallInst
    } else if (!FI.NewToOldValueMap.empty()) {
      // Otherwise, if this is a clone, update the NewToOldValueMap with the new
      // CI return value.
      UpdateNewToOldValueMap(TheCall, NewCall);
    }
  } else if (!FI.NewToOldValueMap.empty()) {
    UpdateNewToOldValueMap(TheCall, NewCall);
  }

  //
  // Copy over the calling convention and attributes of the original call
  // instruction to the new call instruction.
  //
  CallSite(NewCall).setCallingConv(CallSite(TheCall).getCallingConv());

  TheCall->eraseFromParent();
  visitInstruction(*NewCall);
}
예제 #3
0
void RTAssociate::replaceCall(CallSite CS, FuncInfo& FI, DataStructures* DS) {
  const Function *CF = CS.getCalledFunction();
  Instruction *TheCall = CS.getInstruction();

  // If the called function is casted from one function type to another, peer
  // into the cast instruction and pull out the actual function being called.
  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(CS.getCalledValue()))
    if (CE->getOpcode() == Instruction::BitCast &&
        isa<Function>(CE->getOperand(0)))
      CF = cast<Function>(CE->getOperand(0));

  if (isa<InlineAsm>(TheCall->getOperand(0))) {
    errs() << "INLINE ASM: ignoring.  Hoping that's safe.\n";
    return;
  }

  // Ignore calls to NULL pointers.
  if (isa<ConstantPointerNull>(CS.getCalledValue())) {
    errs() << "WARNING: Ignoring call using NULL function pointer.\n";
    return;
  }
  // We need to figure out which local pool descriptors correspond to the pool
  // descriptor arguments passed into the function call.  Calculate a mapping
  // from callee DSNodes to caller DSNodes.  We construct a partial isomophism
  // between the graphs to figure out which pool descriptors need to be passed
  // in.  The roots of this mapping is found from arguments and return values.
  //
  DSGraph::NodeMapTy NodeMapping;
  Instruction *NewCall;
  Value *NewCallee;
  std::vector<const DSNode*> ArgNodes;
  DSGraph *CalleeGraph;  // The callee graph

  // For indirect callees, find any callee since all DS graphs have been
  // merged.
  if (CF) { // Direct calls are nice and simple.
    DEBUG(errs() << "  Handling direct call: " << *TheCall);
    FuncInfo *CFI = getFuncInfo(CF);
    if (CFI == 0 || CFI->Clone == 0) // Nothing to transform...
      return;

    NewCallee = CFI->Clone;
    ArgNodes = CFI->ArgNodes;

    assert ((DS->hasDSGraph (*CF)) && "Function has no ECGraph!\n");
    CalleeGraph = DS->getDSGraph(*CF);
  } else {
    DEBUG(errs() << "  Handling indirect call: " << *TheCall);

    // Here we fill in CF with one of the possible called functions.  Because we
    // merged together all of the arguments to all of the functions in the
    // equivalence set, it doesn't really matter which one we pick.
    // (If the function was cloned, we have to map the cloned call instruction
    // in CS back to the original call instruction.)
    Instruction *OrigInst =
      cast<Instruction>(FI.getOldValueIfAvailable(CS.getInstruction()));

    DSCallGraph::callee_iterator I = DS->getCallGraph().callee_begin(CS);
    if (I != DS->getCallGraph().callee_end(CS))
      CF = *I;

    // If we didn't find the callee in the constructed call graph, try
    // checking in the DSNode itself.
    // This isn't ideal as it means that this call site didn't have inlining
    // happen.
    if (!CF) {
      DSGraph* dg = DS->getDSGraph(*OrigInst->getParent()->getParent());
      DSNode* d = dg->getNodeForValue(OrigInst->getOperand(0)).getNode();
      assert (d && "No DSNode!\n");
      std::vector<const Function*> g;
      d->addFullFunctionList(g);
      if (g.size()) {
        EquivalenceClasses< const GlobalValue *> & EC = dg->getGlobalECs();
        for(std::vector<const Function*>::const_iterator ii = g.begin(), ee = g.end();
            !CF && ii != ee; ++ii) {
          for (EquivalenceClasses<const GlobalValue *>::member_iterator MI = EC.findLeader(*ii);
               MI != EC.member_end(); ++MI) // Loop over members in this set.
            if ((CF = dyn_cast<Function>(*MI))) {
              break;
            }
        }
      }
    }

    //
    // Do an assert unless we're bugpointing something.
    //
//    if ((UsingBugpoint) && (!CF)) return;
    if (!CF)
      errs() << "No Graph for CallSite in "
      << TheCall->getParent()->getParent()->getName().str()
      << " originally "
      << OrigInst->getParent()->getParent()->getName().str()
      << "\n";

    assert (CF && "No call graph info");

    // Get the common graph for the set of functions this call may invoke.
//    if (UsingBugpoint && (!(Graphs.hasDSGraph(*CF)))) return;
    assert ((DS->hasDSGraph(*CF)) && "Function has no DSGraph!\n");
    CalleeGraph = DS->getDSGraph(*CF);

#ifndef NDEBUG
    // Verify that all potential callees at call site have the same DS graph.
    DSCallGraph::callee_iterator E = DS->getCallGraph().callee_end(CS);
    for (; I != E; ++I)
      if (!(*I)->isDeclaration())
        assert(CalleeGraph == DS->getDSGraph(**I) &&
               "Callees at call site do not have a common graph!");
#endif

    // Find the DS nodes for the arguments that need to be added, if any.
    FuncInfo *CFI = getFuncInfo(CF);
    assert(CFI && "No function info for callee at indirect call?");
    ArgNodes = CFI->ArgNodes;

    if (ArgNodes.empty())
      return;           // No arguments to add?  Transformation is a noop!

    // Cast the function pointer to an appropriate type!
    std::vector<Type*> ArgTys(ArgNodes.size(), PoolDescPtrTy);
    for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
         I != E; ++I)
      ArgTys.push_back((*I)->getType());

    FunctionType *FTy = FunctionType::get(TheCall->getType(), ArgTys, false);
    PointerType *PFTy = PointerType::getUnqual(FTy);

    // If there are any pool arguments cast the func ptr to the right type.
    NewCallee = CastInst::CreatePointerCast(CS.getCalledValue(), PFTy, "tmp", TheCall);
  }

  Function::const_arg_iterator FAI = CF->arg_begin(), E = CF->arg_end();
  CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
  for ( ; FAI != E && AI != AE; ++FAI, ++AI)
    if (!isa<Constant>(*AI))
      DSGraph::computeNodeMapping(CalleeGraph->getNodeForValue(FAI),
                                  FI.getDSNodeHFor(*AI), NodeMapping, false);

  assert(AI == AE && "Varargs calls not handled yet!");

  // Map the return value as well...
  if (isa<PointerType>(TheCall->getType()))
    DSGraph::computeNodeMapping(CalleeGraph->getReturnNodeFor(*CF),
                                FI.getDSNodeHFor(TheCall), NodeMapping, false);

  // Okay, now that we have established our mapping, we can figure out which
  // pool descriptors to pass in...
  std::vector<Value*> Args;
  for (unsigned i = 0, e = ArgNodes.size(); i != e; ++i) {
    Value *ArgVal = Constant::getNullValue(PoolDescPtrTy);
    if (NodeMapping.count(ArgNodes[i]))
      if (DSNode *LocalNode = NodeMapping[ArgNodes[i]].getNode())
        if (FI.PoolDescriptors.count(LocalNode))
          ArgVal = FI.PoolDescriptors.find(LocalNode)->second;
    if (isa<Constant > (ArgVal) && cast<Constant > (ArgVal)->isNullValue())
      errs() << "WARNING: NULL POOL ARGUMENTS ARE PASSED IN!\n";
    Args.push_back(ArgVal);
  }

  // Add the rest of the arguments...
  Args.insert(Args.end(), CS.arg_begin(), CS.arg_end());

  //
  // There are circumstances where a function is casted to another type and
  // then called (que horible).  We need to perform a similar cast if the
  // type doesn't match the number of arguments.
  //
  if (Function * NewFunction = dyn_cast<Function>(NewCallee)) {
    FunctionType * NewCalleeType = NewFunction->getFunctionType();
    if (NewCalleeType->getNumParams() != Args.size()) {
      std::vector<Type *> Types;
      Type * FuncTy = FunctionType::get (NewCalleeType->getReturnType(),
                                         Types,
                                         true);
      FuncTy = PointerType::getUnqual (FuncTy);
      NewCallee = new BitCastInst (NewCallee, FuncTy, "", TheCall);
    }
  }

  std::string Name = TheCall->getName();    TheCall->setName("");

  if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
    NewCall = InvokeInst::Create (NewCallee, II->getNormalDest(),
                                  II->getUnwindDest(),
                                  Args, Name, TheCall);
  } else {
    NewCall = CallInst::Create (NewCallee, Args, Name,
                                TheCall);
  }

  TheCall->replaceAllUsesWith(NewCall);
  DEBUG(errs() << "  Result Call: " << *NewCall);

  if (TheCall->getType()->getTypeID() != Type::VoidTyID) {
    // If we are modifying the original function, update the DSGraph...
    DSGraph::ScalarMapTy &SM = FI.G->getScalarMap();
    DSGraph::ScalarMapTy::iterator CII = SM.find(TheCall);
    if (CII != SM.end()) {
      SM[NewCall] = CII->second;
      SM.erase(CII);                     // Destroy the CallInst
    } else if (!FI.NewToOldValueMap.empty()) {
      // Otherwise, if this is a clone, update the NewToOldValueMap with the new
      // CI return value.
      FI.UpdateNewToOldValueMap(TheCall, NewCall);
    }
  } else if (!FI.NewToOldValueMap.empty()) {
    FI.UpdateNewToOldValueMap(TheCall, NewCall);
  }

  //FIXME: attributes on call?
  CallSite(NewCall).setCallingConv(CallSite(TheCall).getCallingConv());

  TheCall->eraseFromParent();
}
예제 #4
0
/// visitGraph - Visit the functions in the specified graph, updating the
/// specified lattice values for all of their uses.
///
void StructureFieldVisitorBase::
visitGraph(DSGraph &DSG, std::multimap<DSNode*, LatticeValue*> &NodeLVs) {
  assert(!NodeLVs.empty() && "No lattice values to compute!");

  // To visit a graph, first step, we visit the instruction making up each
  // function in the graph, but ignore calls when processing them.  We handle
  // call nodes explicitly by looking at call nodes in the graph if needed.  We
  // handle instructions before calls to avoid interprocedural analysis if we
  // can drive lattice values to bottom early.
  //
  SFVInstVisitor IV(DSG, Callbacks, NodeLVs);

  for (DSGraph::retnodes_iterator FI = DSG.retnodes_begin(),
         E = DSG.retnodes_end(); FI != E; ++FI)
    for (Function::iterator BB = FI->first->begin(), E = FI->first->end();
         BB != E; ++BB)
      for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
        if (IV.visit(*I) && NodeLVs.empty())
          return;  // Nothing left to analyze.

  // Keep track of which actual direct callees are handled.
  std::set<Function*> CalleesHandled;

  // Once we have visited all of the instructions in the function bodies, if
  // there are lattice values that have not been driven to bottom, see if any of
  // the nodes involved are passed into function calls.  If so, we potentially
  // have to recursively traverse the call graph.
  for (DSGraph::fc_iterator CS = DSG.fc_begin(), E = DSG.fc_end();
       CS != E; ++CS) {
    // Figure out the mapping from a node in the caller (potentially several)
    // nodes in the callee.
    DSGraph::NodeMapTy CallNodeMap;

    Instruction *TheCall = CS->getCallSite().getInstruction();

    // If this is an indirect function call, assume nothing gets passed through
    // it. FIXME: THIS IS BROKEN!  Just get the ECG for the fn ptr if it's not
    // direct.
    if (CS->isIndirectCall())
      continue;

    // If this is an external function call, it cannot be involved with this
    // node, because otherwise the node would be marked incomplete!
    if (CS->getCalleeFunc()->isExternal())
      continue;

    // If we can handle this function call, remove it from the set of direct
    // calls found by the visitor.
    CalleesHandled.insert(CS->getCalleeFunc());

    std::vector<DSNodeHandle> Args;

    DSGraph *CG = &ECG.getDSGraph(*CS->getCalleeFunc());
    CG->getFunctionArgumentsForCall(CS->getCalleeFunc(), Args);

    if (!CS->getRetVal().isNull())
      DSGraph::computeNodeMapping(Args[0], CS->getRetVal(), CallNodeMap);
    for (unsigned i = 0, e = CS->getNumPtrArgs(); i != e; ++i) {
      if (i == Args.size()-1) break;
      DSGraph::computeNodeMapping(Args[i+1], CS->getPtrArg(i), CallNodeMap);
    }
    Args.clear();

    // The mapping we just computed maps from nodes in the callee to nodes in
    // the caller, so we can't query it efficiently.  Instead of going through
    // the trouble of inverting the map to do this (linear time with the size of
    // the mapping), we just do a linear search to see if any affected nodes are
    // passed into this call.
    bool CallCanModifyDataFlow = false;
    for (DSGraph::NodeMapTy::iterator MI = CallNodeMap.begin(),
           E = CallNodeMap.end(); MI != E; ++MI)
      if (NodeLVs.count(MI->second.getNode()))
        // Okay, the node is passed in, check to see if the call might do
        // something interesting to it (i.e. if analyzing the call can produce
        // anything other than "top").
        if ((CallCanModifyDataFlow = NodeCanPossiblyBeInteresting(MI->first,
                                                                  Callbacks)))
          break;

    // If this function call cannot impact the analysis (either because the
    // nodes we are tracking are not passed into the call, or the DSGraph for
    // the callee tells us that analysis of the callee can't provide interesting
    // information), ignore it.
    if (!CallCanModifyDataFlow)
      continue;

    // Okay, either compute analysis results for the callee function, or reuse
    // results previously computed.
    std::multimap<DSNode*, LatticeValue*> &CalleeFacts = getCalleeFacts(*CG);

    // Merge all of the facts for the callee into the facts for the caller.  If
    // this reduces anything in the caller to 'bottom', remove them.
    for (DSGraph::NodeMapTy::iterator MI = CallNodeMap.begin(),
           E = CallNodeMap.end(); MI != E; ++MI) {
      // If we have Lattice facts in the caller for this node in the callee,
      // merge any information from the callee into the caller.

      // If the node is not accessed in the callee at all, don't update.
      if (MI->first->getType() == Type::VoidTy)
        continue;

      // If there are no data-flow facts live in the caller for this node, don't
      // both processing it.
      std::multimap<DSNode*, LatticeValue*>::iterator NLVI =
        NodeLVs.find(MI->second.getNode());
      if (NLVI == NodeLVs.end()) continue;
          
          
      // Iterate over all of the lattice values that have corresponding fields
      // in the callee, merging in information as we go.  Be careful about the
      // fact that the callee may get passed the address of a substructure and
      // other funny games.
      //if (CalleeFacts.count(const_cast<DSNode*>(MI->first)) == 0) {

      DSNode *CalleeNode = const_cast<DSNode*>(MI->first);

      unsigned CalleeNodeOffset = MI->second.getOffset();
      while (NLVI->first == MI->second.getNode()) {
        // Figure out what offset in the callee this field would land.
        unsigned FieldOff = NLVI->second->getFieldOffset()+CalleeNodeOffset;

        // If the field is not within the callee node, ignore it.
        if (FieldOff >= CalleeNode->getSize()) {
          ++NLVI;
          continue;
        }

        // Okay, check to see if we have a lattice value for the field at offset
        // FieldOff in the callee node.
        const LatticeValue *CalleeLV = 0;

        std::multimap<DSNode*, LatticeValue*>::iterator CFI = 
          CalleeFacts.lower_bound(CalleeNode);
        for (; CFI != CalleeFacts.end() && CFI->first == CalleeNode; ++CFI)
          if (CFI->second->getFieldOffset() == FieldOff) {
            CalleeLV = CFI->second;   // Found it!
            break;
          }
        
        // If we don't, the lattice value hit bottom and we should remove the
        // lattice value in the caller.
        if (!CalleeLV) {
          delete NLVI->second;   // The lattice value hit bottom.
          NodeLVs.erase(NLVI++);
          continue;
        }

        // Finally, if we did find a corresponding entry, merge the information
        // into the caller's lattice value and keep going.
        if (NLVI->second->mergeInValue(CalleeLV)) {
          // Okay, merging these two caused the caller value to hit bottom.
          // Remove it.
          delete NLVI->second;   // The lattice value hit bottom.
          NodeLVs.erase(NLVI++);
        }

        ++NLVI;  // We successfully merged in some information!
      }

      // If we ran out of facts to prove, just exit.
      if (NodeLVs.empty()) return;
    }
  }

  // The local analysis pass inconveniently discards many local function calls
  // from the graph if they are to known functions.  Loop over direct function
  // calls not handled above and visit them as appropriate.
  while (!IV.DirectCallSites.empty()) {
    Instruction *Call = *IV.DirectCallSites.begin();
    IV.DirectCallSites.erase(IV.DirectCallSites.begin());

    // Is this one actually handled by DSA?
    if (CalleesHandled.count(cast<Function>(Call->getOperand(0))))
      continue;

    // Collect the pointers involved in this call.    
    std::vector<Value*> Pointers;
    if (isa<PointerType>(Call->getType()))
      Pointers.push_back(Call);
    for (unsigned i = 1, e = Call->getNumOperands(); i != e; ++i)
      if (isa<PointerType>(Call->getOperand(i)->getType()))
        Pointers.push_back(Call->getOperand(i));

    // If this is an intrinsic function call, figure out which one.
    unsigned IID = cast<Function>(Call->getOperand(0))->getIntrinsicID();

    for (unsigned i = 0, e = Pointers.size(); i != e; ++i) {
      // If any of our lattice values are passed into this call, which is
      // specially handled by the local analyzer, inform the lattice function.
      DSNode *N = DSG.getNodeForValue(Pointers[i]).getNode();
      for (std::multimap<DSNode*, LatticeValue*>::iterator LVI =
             NodeLVs.lower_bound(N); LVI != NodeLVs.end() && LVI->first == N;) {
        bool AtBottom = false;
        switch (IID) {
        default:
          AtBottom = LVI->second->visitRecognizedCall(*Call);
          break;
        case Intrinsic::memset:
          if (Callbacks & Visit::Stores)
            AtBottom = LVI->second->visitMemSet(*cast<CallInst>(Call));
          break;
        }

        if (AtBottom) {
          delete LVI->second;
          NodeLVs.erase(LVI++);
        } else {
          ++LVI;
        }
      }
    }
  }
}
예제 #5
0
/// ProcessNodesReachableFromGlobals - If we inferred anything about nodes
/// reachable from globals, we have to make sure that we incorporate data for
/// all graphs that include those globals due to the nature of the globals
/// graph.
///
void StructureFieldVisitorBase::
ProcessNodesReachableFromGlobals(DSGraph &DSG,
                                 std::multimap<DSNode*,LatticeValue*> &NodeLVs){
  // Start by marking all nodes reachable from globals.
  DSScalarMap &SM = DSG.getScalarMap();
  if (SM.global_begin() == SM.global_end()) return;

  hash_set<const DSNode*> Reachable;
  for (DSScalarMap::global_iterator GI = SM.global_begin(),
         E = SM.global_end(); GI != E; ++GI)
    SM[*GI].getNode()->markReachableNodes(Reachable);
  if (Reachable.empty()) return;
  
  // If any of the nodes with dataflow facts are reachable from the globals
  // graph, we have to do the GG processing step.
  bool MustProcessThroughGlobalsGraph = false;
  for (std::multimap<DSNode*, LatticeValue*>::iterator I = NodeLVs.begin(),
         E = NodeLVs.end(); I != E; ++I)
    if (Reachable.count(I->first)) {
      MustProcessThroughGlobalsGraph = true;
      break;
    }
  
  if (!MustProcessThroughGlobalsGraph) return;
  Reachable.clear();

  // Compute the mapping from DSG to the globals graph.
  DSGraph::NodeMapTy DSGToGGMap;
  DSG.computeGToGGMapping(DSGToGGMap);

  // Most of the times when we find facts about things reachable from globals we
  // we are in the main graph.  This means that we have *all* of the globals
  // graph in this DSG.  To be efficient, we compute the minimum set of globals
  // that can reach any of the NodeLVs facts.
  //
  // I'm not aware of any wonderful way of computing the set of globals that
  // points to the set of nodes in NodeLVs that is not N^2 in either NodeLVs or
  // the number of globals, except to compute the inverse of DSG.  As such, we
  // compute the inverse graph of DSG, which basically has the edges going from
  // pointed to nodes to pointing nodes.  Because we only care about one
  // connectedness properties, we ignore field info.  In addition, we only
  // compute inverse of the portion of the graph reachable from the globals.
  std::set<std::pair<DSNode*,DSNode*> > InverseGraph;

  for (DSScalarMap::global_iterator GI = SM.global_begin(),
         E = SM.global_end(); GI != E; ++GI)
    ComputeInverseGraphFrom(SM[*GI].getNode(), InverseGraph);

  // Okay, now that we have our bastardized inverse graph, compute the set of
  // globals nodes reachable from our lattice nodes.
  for (std::multimap<DSNode*, LatticeValue*>::iterator I = NodeLVs.begin(),
         E = NodeLVs.end(); I != E; ++I)
    ComputeNodesReachableFrom(I->first, InverseGraph, Reachable);
 
  // Now that we know which nodes point to the data flow facts, figure out which
  // globals point to the data flow facts.
  std::set<GlobalValue*> Globals;
  for (hash_set<const DSNode*>::iterator I = Reachable.begin(),
         E = Reachable.end(); I != E; ++I)
    Globals.insert((*I)->globals_begin(), (*I)->globals_end());

  // Finally, loop over all of the DSGraphs for the program, computing
  // information for the graph if not done already, mapping the result into our
  // context.
  for (hash_map<const Function*, DSGraph*>::iterator GI = ECG.DSInfo.begin(),
         E = ECG.DSInfo.end(); GI != E; ++GI) {
    DSGraph &FG = *GI->second;
    // Graphs can contain multiple functions, only process the graph once.
    if (GI->first != FG.retnodes_begin()->first ||
        // Also, do not bother reprocessing DSG.
        &FG == &DSG)
      continue;

    bool GraphUsesGlobal = false;
    for (std::set<GlobalValue*>::iterator I = Globals.begin(),
           E = Globals.end(); I != E; ++I)
      if (FG.getScalarMap().count(*I)) {
        GraphUsesGlobal = true;
        break;
      }

    // If this graph does not contain the global at all, there is no reason to
    // even think about it.
    if (!GraphUsesGlobal) continue;

    // Otherwise, compute the full set of dataflow effects of the function.
    std::multimap<DSNode*, LatticeValue*> &FGF = getCalleeFacts(FG);
    //std::cerr << "Computed: " << FG.getFunctionNames() << "\n";

#if 0
    for (std::multimap<DSNode*, LatticeValue*>::iterator I = FGF.begin(),
           E = FGF.end(); I != E; ++I)
      I->second->dump();
#endif
    // Compute the mapping of nodes in the globals graph to the function's
    // graph.  Note that this function graph may not have nodes (or may have
    // fragments of full nodes) in the globals graph, and we don't want this to
    // pessimize the analysis.
    std::multimap<const DSNode*, std::pair<DSNode*,int> > GraphMap;
    DSGraph::NodeMapTy GraphToGGMap;
    FG.computeGToGGMapping(GraphToGGMap);

    // "Invert" the mapping.  We compute the mapping from the start of a global
    // graph node to a place in the graph's node.  Note that not all of the GG
    // node may be present in the graphs node, so there may be a negative offset
    // involved.
    while (!GraphToGGMap.empty()) {
      DSNode *GN = const_cast<DSNode*>(GraphToGGMap.begin()->first);
      DSNodeHandle &GGNH = GraphToGGMap.begin()->second;
      GraphMap.insert(std::make_pair(GGNH.getNode(),
                                     std::make_pair(GN, -GGNH.getOffset())));
      GraphToGGMap.erase(GraphToGGMap.begin());
    }

    // Loop over all of the dataflow facts that we have computed, mapping them
    // to the globals graph.
    for (std::multimap<DSNode*, LatticeValue*>::iterator I = NodeLVs.begin(),
           E = NodeLVs.end(); I != E; ) {
      bool FactHitBottom = false;

      //I->second->dump();

      assert(I->first->getParentGraph() == &DSG);
      assert(I->second->getNode()->getParentGraph() == &DSG);

      // Node is in the GG?
      DSGraph::NodeMapTy::iterator DSGToGGMapI = DSGToGGMap.find(I->first);
      if (DSGToGGMapI != DSGToGGMap.end()) {
        DSNodeHandle &GGNH = DSGToGGMapI->second;
        const DSNode *GGNode = GGNH.getNode();
        unsigned DSGToGGOffset = GGNH.getOffset();

        // See if there is a node in FG that corresponds to this one.  If not,
        // no information will be computed in this scope, as the memory is not
        // accessed.
        std::multimap<const DSNode*, std::pair<DSNode*,int> >::iterator GMI =
          GraphMap.find(GGNode);

        // LatticeValOffset - The offset from the start of the GG Node to the
        // start of the field we are interested in.
        unsigned LatticeValOffset = I->second->getFieldOffset()+DSGToGGOffset;

        // Loop over all of the nodes in FG that correspond to this single node
        // in the GG.
        for (; GMI != GraphMap.end() && GMI->first == GGNode; ++GMI) {
          // Compute the offset to the field in the user graph.
          unsigned FieldOffset = LatticeValOffset - GMI->second.second;

          // If the field is within the amount of memory accessed by this scope,
          // then there must be a corresponding lattice value.
          DSNode *FGNode = GMI->second.first;
          if (FieldOffset < FGNode->getSize()) {
            LatticeValue *CorrespondingLV = 0;

            std::multimap<DSNode*, LatticeValue*>::iterator FGFI =
              FGF.find(FGNode);
            for (; FGFI != FGF.end() && FGFI->first == FGNode; ++FGFI)
              if (FGFI->second->getFieldOffset() == FieldOffset) {
                CorrespondingLV = FGFI->second;
                break;
              }

            // Finally, if either there was no corresponding fact (because it
            // hit bottom in this scope), or if merging the two pieces of
            // information makes it hit bottom, remember this.
            if (CorrespondingLV == 0 ||
                I->second->mergeInValue(CorrespondingLV))
              FactHitBottom = true;
          }
        }
      }

      if (FactHitBottom) {
        delete I->second;
        NodeLVs.erase(I++);
        if (NodeLVs.empty()) return;
      } else {
        ++I;
      }
    }
  }
}