1 files changed, 219 insertions, 0 deletions
diff --git a/lib/Analysis/IPA/CallGraph.cpp b/lib/Analysis/IPA/CallGraph.cpp
new file mode 100644
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+++ b/lib/Analysis/IPA/CallGraph.cpp
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+//===- CallGraph.cpp - Build a Module's call graph ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the CallGraph class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/CallGraph.h"
+#include "llvm/Module.h"
+#include "llvm/Instructions.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/ADT/STLExtras.h"
+#include <iostream>
+using namespace llvm;
+
+static RegisterAnalysis<CallGraph> X("callgraph", "Call Graph Construction");
+
+// getNodeFor - Return the node for the specified function or create one if it
+// does not already exist.
+//
+CallGraphNode *CallGraph::getNodeFor(Function *F) {
+  CallGraphNode *&CGN = FunctionMap[F];
+  if (CGN) return CGN;
+
+  assert((!F || F->getParent() == Mod) && "Function not in current module!");
+  return CGN = new CallGraphNode(F);
+}
+
+static bool isOnlyADirectCall(Function *F, CallSite CS) {
+  if (!CS.getInstruction()) return false;
+  for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); I != E; ++I)
+    if (*I == F) return false;
+  return true;
+}
+
+// addToCallGraph - Add a function to the call graph, and link the node to all
+// of the functions that it calls.
+//
+void CallGraph::addToCallGraph(Function *F) {
+  CallGraphNode *Node = getNodeFor(F);
+
+  // If this function has external linkage, anything could call it...
+  if (!F->hasInternalLinkage()) {
+    ExternalCallingNode->addCalledFunction(Node);
+
+    // Found the entry point?
+    if (F->getName() == "main") {
+      if (Root)    // Found multiple external mains?  Don't pick one.
+        Root = ExternalCallingNode;
+      else
+        Root = Node;          // Found a main, keep track of it!
+    }
+  }
+
+  // If this function is not defined in this translation unit, it could call
+  // anything.
+  if (F->isExternal() && !F->getIntrinsicID())
+    Node->addCalledFunction(CallsExternalNode);
+
+  // Loop over all of the users of the function... looking for callers...
+  //
+  bool isUsedExternally = false;
+  for (Value::use_iterator I = F->use_begin(), E = F->use_end(); I != E; ++I) {
+    if (Instruction *Inst = dyn_cast<Instruction>(*I)) {
+      if (isOnlyADirectCall(F, CallSite::get(Inst)))
+        getNodeFor(Inst->getParent()->getParent())->addCalledFunction(Node);
+      else
+        isUsedExternally = true;
+    } else if (GlobalValue *GV = dyn_cast<GlobalValue>(*I)) {
+      for (Value::use_iterator I = GV->use_begin(), E = GV->use_end();
+           I != E; ++I)
+        if (Instruction *Inst = dyn_cast<Instruction>(*I)) {
+          if (isOnlyADirectCall(F, CallSite::get(Inst)))
+            getNodeFor(Inst->getParent()->getParent())->addCalledFunction(Node);
+          else
+            isUsedExternally = true;
+        } else {
+          isUsedExternally = true;
+        }
+    } else {                        // Can't classify the user!
+      isUsedExternally = true;
+    }
+  }
+  if (isUsedExternally)
+    ExternalCallingNode->addCalledFunction(Node);
+
+  // Look for an indirect function call...
+  for (Function::iterator BB = F->begin(), BBE = F->end(); BB != BBE; ++BB)
+    for (BasicBlock::iterator II = BB->begin(), IE = BB->end(); II != IE; ++II){
+      CallSite CS = CallSite::get(II);
+      if (CS.getInstruction() && !CS.getCalledFunction())
+        Node->addCalledFunction(CallsExternalNode);
+    }
+}
+
+bool CallGraph::runOnModule(Module &M) {
+  destroy();
+
+  Mod = &M;
+  ExternalCallingNode = getNodeFor(0);
+  CallsExternalNode = new CallGraphNode(0);
+  Root = 0;
+
+  // Add every function to the call graph...
+  for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
+    addToCallGraph(I);
+
+  // If we didn't find a main function, use the external call graph node
+  if (Root == 0) Root = ExternalCallingNode;
+
+  return false;
+}
+
+void CallGraph::destroy() {
+  for (FunctionMapTy::iterator I = FunctionMap.begin(), E = FunctionMap.end();
+       I != E; ++I)
+    delete I->second;
+  FunctionMap.clear();
+  delete CallsExternalNode;
+  CallsExternalNode = 0;
+}
+
+void CallGraphNode::print(std::ostream &OS) const {
+  if (Function *F = getFunction())
+    OS << "Call graph node for function: '" << F->getName() <<"'\n";
+  else
+    OS << "Call graph node <<null function: 0x" << this << ">>:\n";
+
+  for (const_iterator I = begin(), E = end(); I != E; ++I)
+    if ((*I)->getFunction())
+      OS << "  Calls function '" << (*I)->getFunction()->getName() << "'\n";
+    else
+      OS << "  Calls external node\n";
+  OS << "\n";
+}
+
+void CallGraphNode::dump() const { print(std::cerr); }
+
+void CallGraph::print(std::ostream &OS, const Module *M) const {
+  OS << "CallGraph Root is: ";
+  if (Function *F = getRoot()->getFunction())
+    OS << F->getName() << "\n";
+  else
+    OS << "<<null function: 0x" << getRoot() << ">>\n";
+
+  for (CallGraph::const_iterator I = begin(), E = end(); I != E; ++I)
+    I->second->print(OS);
+}
+
+void CallGraph::dump() const {
+  print(std::cerr, 0);
+}
+
+
+//===----------------------------------------------------------------------===//
+// Implementations of public modification methods
+//
+
+// removeFunctionFromModule - Unlink the function from this module, returning
+// it.  Because this removes the function from the module, the call graph node
+// is destroyed.  This is only valid if the function does not call any other
+// functions (ie, there are no edges in it's CGN).  The easiest way to do this
+// is to dropAllReferences before calling this.
+//
+Function *CallGraph::removeFunctionFromModule(CallGraphNode *CGN) {
+  assert(CGN->CalledFunctions.empty() && "Cannot remove function from call "
+         "graph if it references other functions!");
+  Function *F = CGN->getFunction(); // Get the function for the call graph node
+  delete CGN;                       // Delete the call graph node for this func
+  FunctionMap.erase(F);             // Remove the call graph node from the map
+
+  Mod->getFunctionList().remove(F);
+  return F;
+}
+
+// changeFunction - This method changes the function associated with this
+// CallGraphNode, for use by transformations that need to change the prototype
+// of a Function (thus they must create a new Function and move the old code
+// over).
+void CallGraph::changeFunction(Function *OldF, Function *NewF) {
+  iterator I = FunctionMap.find(OldF);
+  CallGraphNode *&New = FunctionMap[NewF];
+  assert(I != FunctionMap.end() && I->second && !New &&
+         "OldF didn't exist in CG or NewF already does!");
+  New = I->second;
+  New->F = NewF;
+  FunctionMap.erase(I);
+}
+
+
+void CallGraph::stub() {}
+
+void CallGraphNode::removeCallEdgeTo(CallGraphNode *Callee) {
+  for (unsigned i = CalledFunctions.size(); ; --i) {
+    assert(i && "Cannot find callee to remove!");
+    if (CalledFunctions[i-1] == Callee) {
+      CalledFunctions.erase(CalledFunctions.begin()+i-1);
+      return;
+    }
+  }
+}
+
+// removeAnyCallEdgeTo - This method removes any call edges from this node to
+// the specified callee function.  This takes more time to execute than
+// removeCallEdgeTo, so it should not be used unless necessary.
+void CallGraphNode::removeAnyCallEdgeTo(CallGraphNode *Callee) {
+  for (unsigned i = 0, e = CalledFunctions.size(); i != e; ++i)
+    if (CalledFunctions[i] == Callee) {
+      CalledFunctions[i] = CalledFunctions.back();
+      CalledFunctions.pop_back();
+      --i; --e;
+    }
+}