[llvm] r206450 - [LCG] Just move the allocator (now that we can) when moving a call

[Chandler Carruth]

Author: chandlerc
Date: Thu Apr 17 02:25:59 2014
New Revision: 206450

URL: http://llvm.org/viewvc/llvm-project?rev=206450&view=rev
Log:
[LCG] Just move the allocator (now that we can) when moving a call
graph. This simplifies the custom move constructor operation to one of
walking the graph and updating the 'up' pointers to point to the new
location of the graph. Switch the nodes from a reference to a pointer
for the 'up' edge to facilitate this.

Modified:
    llvm/trunk/include/llvm/Analysis/LazyCallGraph.h
    llvm/trunk/lib/Analysis/LazyCallGraph.cpp

Modified: llvm/trunk/include/llvm/Analysis/LazyCallGraph.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/LazyCallGraph.h?rev=206450&r1=206449&r2=206450&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/LazyCallGraph.h (original)
+++ llvm/trunk/include/llvm/Analysis/LazyCallGraph.h Thu Apr 17 02:25:59 2014
@@ -230,9 +230,6 @@ private:
 
   /// \brief Helper to copy a node from another graph into this one.
   Node *copyInto(const Node &OtherN);
-
-  /// \brief Helper to move a node from another graph into this one.
-  Node *moveInto(Node &&OtherN);
 };
 
 /// \brief A node in the call graph.
@@ -243,7 +240,7 @@ private:
 class LazyCallGraph::Node {
   friend class LazyCallGraph;
 
-  LazyCallGraph &G;
+  LazyCallGraph *G;
   Function &F;
   mutable NodeVectorT Callees;
   SmallPtrSet<Function *, 4> CalleeSet;
@@ -265,8 +262,8 @@ public:
     return F;
   };
 
-  iterator begin() const { return iterator(G, Callees); }
-  iterator end() const { return iterator(G, Callees, iterator::IsAtEndT()); }
+  iterator begin() const { return iterator(*G, Callees); }
+  iterator end() const { return iterator(*G, Callees, iterator::IsAtEndT()); }
 
   /// Equality is defined as address equality.
   bool operator==(const Node &N) const { return this == &N; }

Modified: llvm/trunk/lib/Analysis/LazyCallGraph.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LazyCallGraph.cpp?rev=206450&r1=206449&r2=206450&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LazyCallGraph.cpp (original)
+++ llvm/trunk/lib/Analysis/LazyCallGraph.cpp Thu Apr 17 02:25:59 2014
@@ -46,7 +46,7 @@ static void findCallees(
   }
 }
 
-LazyCallGraph::Node::Node(LazyCallGraph &G, Function &F) : G(G), F(F) {
+LazyCallGraph::Node::Node(LazyCallGraph &G, Function &F) : G(&G), F(F) {
   SmallVector<Constant *, 16> Worklist;
   SmallPtrSet<Constant *, 16> Visited;
   // Find all the potential callees in this function. First walk the
@@ -65,7 +65,7 @@ LazyCallGraph::Node::Node(LazyCallGraph
 }
 
 LazyCallGraph::Node::Node(LazyCallGraph &G, const Node &OtherN)
-    : G(G), F(OtherN.F), CalleeSet(OtherN.CalleeSet) {
+    : G(&G), F(OtherN.F), CalleeSet(OtherN.CalleeSet) {
   // Loop over the other node's callees, adding the Function*s to our list
   // directly, and recursing to add the Node*s.
   Callees.reserve(OtherN.Callees.size());
@@ -76,16 +76,6 @@ LazyCallGraph::Node::Node(LazyCallGraph
       Callees.push_back(G.copyInto(*OtherCallee.get<Node *>()));
 }
 
-LazyCallGraph::Node::Node(LazyCallGraph &G, Node &&OtherN)
-    : G(G), F(OtherN.F), Callees(std::move(OtherN.Callees)),
-      CalleeSet(std::move(OtherN.CalleeSet)) {
-  // Loop over our Callees. They've been moved from another node, but we need
-  // to move the Node*s to live under our bump ptr allocator.
-  for (auto &Callee : Callees)
-    if (Node *ChildN = Callee.dyn_cast<Node *>())
-      Callee = G.moveInto(std::move(*ChildN));
-}
-
 LazyCallGraph::LazyCallGraph(Module &M) {
   for (Function &F : M)
     if (!F.isDeclaration() && !F.hasLocalLinkage())
@@ -113,18 +103,22 @@ LazyCallGraph::LazyCallGraph(const LazyC
       EntryNodes.push_back(copyInto(*EntryNode.get<Node *>()));
 }
 
-// FIXME: This would be crazy simpler if BumpPtrAllocator were movable without
-// invalidating any of the allocated memory. We should make that be the case at
-// some point and delete this.
 LazyCallGraph::LazyCallGraph(LazyCallGraph &&G)
-    : EntryNodes(std::move(G.EntryNodes)),
+    : BPA(std::move(G.BPA)), EntryNodes(std::move(G.EntryNodes)),
       EntryNodeSet(std::move(G.EntryNodeSet)) {
-  // Loop over our EntryNodes. They've been moved from another graph, so we
-  // need to move the Node*s to live under our bump ptr allocator. We can just
-  // do this in-place.
+  // Process all nodes updating the graph pointers.
+  SmallVector<Node *, 16> Worklist;
   for (auto &Entry : EntryNodes)
     if (Node *EntryN = Entry.dyn_cast<Node *>())
-      Entry = moveInto(std::move(*EntryN));
+      Worklist.push_back(EntryN);
+
+  while (!Worklist.empty()) {
+    Node *N = Worklist.pop_back_val();
+    N->G = this;
+    for (auto &Callee : N->Callees)
+      if (Node *CalleeN = Callee.dyn_cast<Node *>())
+        Worklist.push_back(CalleeN);
+  }
 }
 
 LazyCallGraph::Node *LazyCallGraph::insertInto(Function &F, Node *&MappedN) {
@@ -139,14 +133,6 @@ LazyCallGraph::Node *LazyCallGraph::copy
   return new (N = BPA.Allocate()) Node(*this, OtherN);
 }
 
-LazyCallGraph::Node *LazyCallGraph::moveInto(Node &&OtherN) {
-  Node *&N = NodeMap[&OtherN.F];
-  if (N)
-    return N;
-
-  return new (N = BPA.Allocate()) Node(*this, std::move(OtherN));
-}
-
 char LazyCallGraphAnalysis::PassID;
 
 LazyCallGraphPrinterPass::LazyCallGraphPrinterPass(raw_ostream &OS) : OS(OS) {}