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DSCallSiteIterator.h

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00001 //===- DSCallSiteIterator.h - Iterator for DSGraph call sites ---*- C++ -*-===//
00002 // 
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 // 
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This file implements an iterator for complete call sites in DSGraphs.  This
00011 // code can either iterator over the normal call list or the aux calls list, and
00012 // is used by the TD and BU passes.
00013 //
00014 //===----------------------------------------------------------------------===//
00015 
00016 #ifndef DSCALLSITEITERATOR_H
00017 #define DSCALLSITEITERATOR_H
00018 
00019 #include "llvm/Analysis/DataStructure/DSGraph.h"
00020 #include "llvm/Function.h"
00021 
00022 namespace llvm {
00023 
00024 struct DSCallSiteIterator {
00025   // FCs are the edges out of the current node are the call site targets...
00026   const std::vector<DSCallSite> *FCs;
00027   unsigned CallSite;
00028   unsigned CallSiteEntry;
00029 
00030   DSCallSiteIterator(const std::vector<DSCallSite> &CS) : FCs(&CS) {
00031     CallSite = 0; CallSiteEntry = 0;
00032     advanceToValidCallee();
00033   }
00034 
00035   // End iterator ctor...
00036   DSCallSiteIterator(const std::vector<DSCallSite> &CS, bool) : FCs(&CS) {
00037     CallSite = FCs->size(); CallSiteEntry = 0;
00038   }
00039 
00040   static bool isVAHackFn(const Function *F) {
00041     return F->getName() == "printf"  || F->getName() == "sscanf" ||
00042       F->getName() == "fprintf" || F->getName() == "open" ||
00043       F->getName() == "sprintf" || F->getName() == "fputs" ||
00044       F->getName() == "fscanf";
00045   }
00046 
00047   // isUnresolvableFunction - Return true if this is an unresolvable
00048   // external function.  A direct or indirect call to this cannot be resolved.
00049   // 
00050   static bool isUnresolvableFunc(const Function* callee) {
00051     return callee->isExternal() && !isVAHackFn(callee);
00052   } 
00053 
00054   void advanceToValidCallee() {
00055     while (CallSite < FCs->size()) {
00056       if ((*FCs)[CallSite].isDirectCall()) {
00057         if (CallSiteEntry == 0 &&        // direct call only has one target...
00058             ! isUnresolvableFunc((*FCs)[CallSite].getCalleeFunc()))
00059           return;                       // and not an unresolvable external func
00060       } else {
00061         DSNode *CalleeNode = (*FCs)[CallSite].getCalleeNode();
00062         if (CallSiteEntry || isCompleteNode(CalleeNode)) {
00063           const std::vector<GlobalValue*> &Callees = CalleeNode->getGlobals();
00064           while (CallSiteEntry < Callees.size()) {
00065             if (isa<Function>(Callees[CallSiteEntry]))
00066               return;
00067             ++CallSiteEntry;
00068           }
00069         }
00070       }
00071       CallSiteEntry = 0;
00072       ++CallSite;
00073     }
00074   }
00075   
00076   // isCompleteNode - Return true if we know all of the targets of this node,
00077   // and if the call sites are not external.
00078   //
00079   static inline bool isCompleteNode(DSNode *N) {
00080     if (N->isIncomplete()) return false;
00081     const std::vector<GlobalValue*> &Callees = N->getGlobals();
00082     for (unsigned i = 0, e = Callees.size(); i != e; ++i)
00083       if (isUnresolvableFunc(cast<Function>(Callees[i])))
00084         return false;               // Unresolvable external function found...
00085     return true;  // otherwise ok
00086   }
00087 
00088 public:
00089   static DSCallSiteIterator begin_aux(DSGraph &G) {
00090     return G.getAuxFunctionCalls();
00091   }
00092   static DSCallSiteIterator end_aux(DSGraph &G) {
00093     return DSCallSiteIterator(G.getAuxFunctionCalls(), true);
00094   }
00095   static DSCallSiteIterator begin_std(DSGraph &G) {
00096     return G.getFunctionCalls();
00097   }
00098   static DSCallSiteIterator end_std(DSGraph &G) {
00099     return DSCallSiteIterator(G.getFunctionCalls(), true);
00100   }
00101   static DSCallSiteIterator begin(std::vector<DSCallSite> &CSs) { return CSs; }
00102   static DSCallSiteIterator end(std::vector<DSCallSite> &CSs) {
00103     return DSCallSiteIterator(CSs, true);
00104   }
00105   bool operator==(const DSCallSiteIterator &CSI) const {
00106     return CallSite == CSI.CallSite && CallSiteEntry == CSI.CallSiteEntry;
00107   }
00108   bool operator!=(const DSCallSiteIterator &CSI) const {
00109     return !operator==(CSI);
00110   }
00111 
00112   unsigned getCallSiteIdx() const { return CallSite; }
00113   const DSCallSite &getCallSite() const { return (*FCs)[CallSite]; }
00114 
00115   Function *operator*() const {
00116     if ((*FCs)[CallSite].isDirectCall()) {
00117       return (*FCs)[CallSite].getCalleeFunc();
00118     } else {
00119       DSNode *Node = (*FCs)[CallSite].getCalleeNode();
00120       return cast<Function>(Node->getGlobals()[CallSiteEntry]);
00121     }
00122   }
00123 
00124   DSCallSiteIterator& operator++() {                // Preincrement
00125     ++CallSiteEntry;
00126     advanceToValidCallee();
00127     return *this;
00128   }
00129   DSCallSiteIterator operator++(int) { // Postincrement
00130     DSCallSiteIterator tmp = *this; ++*this; return tmp; 
00131   }
00132 };
00133 
00134 } // End llvm namespace
00135 
00136 #endif