Add spliceFunction to the CallGraph interface. This allows users to efficiently

update a callGraph when performing the common operation of splicing the body to
a new function and updating all callers (such as via RAUW).

No users yet, though this is intended for DeadArgumentElimination as part of
PR8887.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122728 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Analysis/CallGraph.h b/include/llvm/Analysis/CallGraph.h
index 9dfe89416ae476918151a964c348af7e21700752..089f322e4a86d3b85bed95e82f86b7322d07e95a 100644 (file)
--- a/include/llvm/Analysis/CallGraph.h
+++ b/include/llvm/Analysis/CallGraph.h
@@ -138,6 +138,13 @@ public:
   /// not already exist.
   CallGraphNode *getOrInsertFunction(const Function *F);
 
+  /// spliceFunction - Replace the function represented by this node by another.
+  /// This does not rescan the body of the function, so it is suitable when
+  /// splicing the body of one function to another while also updating all
+  /// callers from the old function to the new.
+  ///
+  void spliceFunction(const Function *From, const Function *To);
+
   //===---------------------------------------------------------------------
   // Pass infrastructure interface glue code.
   //
@@ -163,8 +170,10 @@ protected:
 // CallGraphNode class definition.
 //
 class CallGraphNode {
-  AssertingVH<Function> F;
+  friend class CallGraph;
   
+  AssertingVH<Function> F;
+
   // CallRecord - This is a pair of the calling instruction (a call or invoke)
   // and the callgraph node being called.
 public:

diff --git a/lib/Analysis/IPA/CallGraph.cpp b/lib/Analysis/IPA/CallGraph.cpp
index f2d747089d5abd02f275e002ea7001c5353372ba..690c4b4b6f1a63426283e3d43d79837f91dbb6f8 100644 (file)
--- a/lib/Analysis/IPA/CallGraph.cpp
+++ b/lib/Analysis/IPA/CallGraph.cpp
@@ -230,6 +230,21 @@ Function *CallGraph::removeFunctionFromModule(CallGraphNode *CGN) {
   return F;
 }
 
+/// spliceFunction - Replace the function represented by this node by another.
+/// This does not rescan the body of the function, so it is suitable when
+/// splicing the body of the old function to the new while also updating all
+/// callers from old to new.
+///
+void CallGraph::spliceFunction(const Function *From, const Function *To) {
+  assert(FunctionMap.count(From) && "No CallGraphNode for function!");
+  assert(!FunctionMap.count(To) &&
+         "Pointing CallGraphNode at a function that already exists");
+  FunctionMapTy::iterator I = FunctionMap.find(From);
+  I->second->F = const_cast<Function*>(To);
+  FunctionMap[To] = I->second;
+  FunctionMap.erase(I);
+}
+
 // getOrInsertFunction - This method is identical to calling operator[], but
 // it will insert a new CallGraphNode for the specified function if one does
 // not already exist.
@@ -276,7 +291,6 @@ void CallGraphNode::removeCallEdgeFor(CallSite CS) {
   }
 }
 
-
 // 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.