1 //===- TopDownClosure.cpp - Compute the top-down interprocedure closure ---===//
3 // This file implements the TDDataStructures class, which represents the
4 // Top-down Interprocedural closure of the data structure graph over the
5 // program. This is useful (but not strictly necessary?) for applications
6 // like pointer analysis.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/Analysis/DataStructure.h"
11 #include "llvm/Analysis/DSGraph.h"
12 #include "llvm/Module.h"
13 #include "llvm/DerivedTypes.h"
14 #include "Support/Statistic.h"
16 static RegisterAnalysis<TDDataStructures>
17 Y("tddatastructure", "Top-down Data Structure Analysis Closure");
19 // releaseMemory - If the pass pipeline is done with this pass, we can release
20 // our memory... here...
22 void TDDataStructures::releaseMemory() {
23 for (std::map<const Function*, DSGraph*>::iterator I = DSInfo.begin(),
24 E = DSInfo.end(); I != E; ++I)
27 // Empty map so next time memory is released, data structures are not
32 // run - Calculate the top down data structure graphs for each function in the
35 bool TDDataStructures::run(Module &M) {
36 // Simply calculate the graphs for each function...
37 for (Module::reverse_iterator I = M.rbegin(), E = M.rend(); I != E; ++I)
43 /// ResolveCallSite - This method is used to link the actual arguments together
44 /// with the formal arguments for a function call in the top-down closure. This
45 /// method assumes that the call site arguments have been mapped into nodes
46 /// local to the specified graph.
48 void TDDataStructures::ResolveCallSite(DSGraph &Graph,
49 const DSCallSite &CallSite) {
50 // Resolve all of the function formal arguments...
51 Function &F = Graph.getFunction();
52 Function::aiterator AI = F.abegin();
54 for (unsigned i = 0, e = CallSite.getNumPtrArgs(); i != e; ++i, ++AI) {
55 // Advance the argument iterator to the first pointer argument...
56 while (!DataStructureAnalysis::isPointerType(AI->getType())) ++AI;
58 // TD ...Merge the formal arg scalar with the actual arg node
59 DSNodeHandle &NodeForFormal = Graph.getNodeForValue(AI);
60 if (NodeForFormal.getNode())
61 NodeForFormal.mergeWith(CallSite.getPtrArg(i));
64 // Merge returned node in the caller with the "return" node in callee
65 if (CallSite.getRetVal().getNode() && Graph.getRetNode().getNode())
66 Graph.getRetNode().mergeWith(CallSite.getRetVal());
70 static DSNodeHandle copyHelper(const DSNodeHandle* fromNode,
71 std::map<const DSNode*, DSNode*> *NodeMap) {
72 return DSNodeHandle((*NodeMap)[fromNode->getNode()], fromNode->getOffset());
76 DSGraph &TDDataStructures::calculateGraph(Function &F) {
77 // Make sure this graph has not already been calculated, or that we don't get
78 // into an infinite loop with mutually recursive functions.
80 DSGraph *&Graph = DSInfo[&F];
81 if (Graph) return *Graph;
83 BUDataStructures &BU = getAnalysis<BUDataStructures>();
84 DSGraph &BUGraph = BU.getDSGraph(F);
85 Graph = new DSGraph(BUGraph);
87 const std::vector<DSCallSite> *CallSitesP = BU.getCallSites(F);
88 if (CallSitesP == 0) {
89 DEBUG(std::cerr << " [TD] No callers for: " << F.getName() << "\n");
90 return *Graph; // If no call sites, the graph is the same as the BU graph!
93 // Loop over all call sites of this function, merging each one into this
96 DEBUG(std::cerr << " [TD] Inlining callers for: " << F.getName() << "\n");
97 const std::vector<DSCallSite> &CallSites = *CallSitesP;
98 for (unsigned c = 0, ce = CallSites.size(); c != ce; ++c) {
99 const DSCallSite &CallSite = CallSites[c]; // Copy
100 Function &Caller = CallSite.getCaller();
101 assert(!Caller.isExternal() && "Externals function cannot 'call'!");
103 DEBUG(std::cerr << "\t [TD] Inlining caller #" << c << " '"
104 << Caller.getName() << "' into callee: " << F.getName() << "\n");
107 // Self-recursive call: this can happen after a cycle of calls is inlined.
108 ResolveCallSite(*Graph, CallSite);
110 // Recursively compute the graph for the Caller. That should
111 // be fully resolved except if there is mutual recursion...
113 DSGraph &CG = calculateGraph(Caller); // Graph to inline
115 DEBUG(std::cerr << "\t\t[TD] Got graph for " << Caller.getName()
116 << " in: " << F.getName() << "\n");
118 // These two maps keep track of where scalars in the old graph _used_
119 // to point to, and of new nodes matching nodes of the old graph.
120 std::map<Value*, DSNodeHandle> OldValMap;
121 std::map<const DSNode*, DSNode*> OldNodeMap;
123 // Clone the Caller's graph into the current graph, keeping
124 // track of where scalars in the old graph _used_ to point...
125 // Do this here because it only needs to happens once for each Caller!
126 // Strip scalars but not allocas since they are alive in callee.
128 DSNodeHandle RetVal = Graph->cloneInto(CG, OldValMap, OldNodeMap,
129 /*StripScalars*/ true,
130 /*StripAllocas*/ false,
131 /*CopyCallers*/ true,
132 /*CopyOrigCalls*/false);
134 // Make a temporary copy of the call site, and transform the argument node
136 DSCallSite TmpCallSite(CallSite, std::bind2nd(std::ptr_fun(©Helper),
138 ResolveCallSite(*Graph, CallSite);
142 // Recompute the Incomplete markers and eliminate unreachable nodes.
143 Graph->maskIncompleteMarkers();
144 Graph->markIncompleteNodes(/*markFormals*/ !F.hasInternalLinkage()
145 /*&& FIXME: NEED TO CHECK IF ALL CALLERS FOUND!*/);
146 Graph->removeDeadNodes(/*KeepAllGlobals*/ false, /*KeepCalls*/ false);
148 DEBUG(std::cerr << " [TD] Done inlining callers for: " << F.getName() << " ["
149 << Graph->getGraphSize() << "+" << Graph->getFunctionCalls().size()