Add the ability to "intern" FoldingSetNodeID data into a
BumpPtrAllocator-allocated region to allow it to be stored in a more
compact form and to avoid the need for a non-trivial destructor call.

Use this new mechanism in ScalarEvolution instead of
FastFoldingSetNode to avoid leaking memory in the case where a
FoldingSetNodeID uses heap storage, and to reduce overall memory
usage.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98829 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/ADT/FoldingSet.h b/include/llvm/ADT/FoldingSet.h
index 81dc469..e8979bb 100644
--- a/include/llvm/ADT/FoldingSet.h
+++ b/include/llvm/ADT/FoldingSet.h
@@ -23,6 +23,7 @@
 namespace llvm {
   class APFloat;
   class APInt;
+  class BumpPtrAllocator;
 
 /// This folding set used for two purposes:
 ///   1. Given information about a node we want to create, look up the unique
@@ -198,6 +199,23 @@
 };
 
 //===--------------------------------------------------------------------===//
+/// FoldingSetNodeIDRef - This class describes a reference to an interned
+/// FoldingSetNodeID, which can be a useful to store node id data rather
+/// than using plain FoldingSetNodeIDs, since the 32-element SmallVector
+/// is often much larger than necessary, and the possibility of heap
+/// allocation means it requires a non-trivial destructor call.
+class FoldingSetNodeIDRef {
+  unsigned* Data;
+  size_t Size;
+public:
+  FoldingSetNodeIDRef() : Data(0), Size(0) {}
+  FoldingSetNodeIDRef(unsigned *D, size_t S) : Data(D), Size(S) {}
+
+  unsigned *getData() const { return Data; }
+  size_t getSize() const { return Size; }
+};
+
+//===--------------------------------------------------------------------===//
 /// FoldingSetNodeID - This class is used to gather all the unique data bits of
 /// a node.  When all the bits are gathered this class is used to produce a
 /// hash value for the node.
@@ -210,11 +228,8 @@
 public:
   FoldingSetNodeID() {}
 
-  /// getRawData - Return the ith entry in the Bits data.
-  ///
-  unsigned getRawData(unsigned i) const {
-    return Bits[i];
-  }
+  FoldingSetNodeID(FoldingSetNodeIDRef Ref)
+    : Bits(Ref.getData(), Ref.getData() + Ref.getSize()) {}
 
   /// Add* - Add various data types to Bit data.
   ///
@@ -242,6 +257,11 @@
   /// operator== - Used to compare two nodes to each other.
   ///
   bool operator==(const FoldingSetNodeID &RHS) const;
+
+  /// Intern - Copy this node's data to a memory region allocated from the
+  /// given allocator and return a FoldingSetNodeIDRef describing the
+  /// interned data.
+  FoldingSetNodeIDRef Intern(BumpPtrAllocator &Allocator) const;
 };
 
 // Convenience type to hide the implementation of the folding set.
diff --git a/include/llvm/Analysis/ScalarEvolution.h b/include/llvm/Analysis/ScalarEvolution.h
index 96d29ba..ab13a9d 100644
--- a/include/llvm/Analysis/ScalarEvolution.h
+++ b/include/llvm/Analysis/ScalarEvolution.h
@@ -49,7 +49,11 @@
   /// are opaque objects that the client is not allowed to do much with
   /// directly.
   ///
-  class SCEV : public FastFoldingSetNode {
+  class SCEV : public FoldingSetNode {
+    /// FastID - A reference to an Interned FoldingSetNodeID for this node.
+    /// The ScalarEvolution's BumpPtrAllocator holds the data.
+    FoldingSetNodeIDRef FastID;
+
     // The SCEV baseclass this node corresponds to
     const unsigned short SCEVType;
 
@@ -64,11 +68,14 @@
   protected:
     virtual ~SCEV();
   public:
-    explicit SCEV(const FoldingSetNodeID &ID, unsigned SCEVTy) :
-      FastFoldingSetNode(ID), SCEVType(SCEVTy), SubclassData(0) {}
+    explicit SCEV(const FoldingSetNodeIDRef ID, unsigned SCEVTy) :
+      FastID(ID), SCEVType(SCEVTy), SubclassData(0) {}
 
     unsigned getSCEVType() const { return SCEVType; }
 
+    /// Profile - FoldingSet support.
+    void Profile(FoldingSetNodeID& ID) { ID = FastID; }
+
     /// isLoopInvariant - Return true if the value of this SCEV is unchanging in
     /// the specified loop.
     virtual bool isLoopInvariant(const Loop *L) const = 0;
diff --git a/include/llvm/Analysis/ScalarEvolutionExpressions.h b/include/llvm/Analysis/ScalarEvolutionExpressions.h
index 27539a3..7424203 100644
--- a/include/llvm/Analysis/ScalarEvolutionExpressions.h
+++ b/include/llvm/Analysis/ScalarEvolutionExpressions.h
@@ -37,7 +37,7 @@
     friend class ScalarEvolution;
 
     ConstantInt *V;
-    SCEVConstant(const FoldingSetNodeID &ID, ConstantInt *v) :
+    SCEVConstant(const FoldingSetNodeIDRef ID, ConstantInt *v) :
       SCEV(ID, scConstant), V(v) {}
   public:
     ConstantInt *getValue() const { return V; }
@@ -81,7 +81,7 @@
     const SCEV *Op;
     const Type *Ty;
 
-    SCEVCastExpr(const FoldingSetNodeID &ID,
+    SCEVCastExpr(const FoldingSetNodeIDRef ID,
                  unsigned SCEVTy, const SCEV *op, const Type *ty);
 
   public:
@@ -120,7 +120,7 @@
   class SCEVTruncateExpr : public SCEVCastExpr {
     friend class ScalarEvolution;
 
-    SCEVTruncateExpr(const FoldingSetNodeID &ID,
+    SCEVTruncateExpr(const FoldingSetNodeIDRef ID,
                      const SCEV *op, const Type *ty);
 
   public:
@@ -140,7 +140,7 @@
   class SCEVZeroExtendExpr : public SCEVCastExpr {
     friend class ScalarEvolution;
 
-    SCEVZeroExtendExpr(const FoldingSetNodeID &ID,
+    SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID,
                        const SCEV *op, const Type *ty);
 
   public:
@@ -160,7 +160,7 @@
   class SCEVSignExtendExpr : public SCEVCastExpr {
     friend class ScalarEvolution;
 
-    SCEVSignExtendExpr(const FoldingSetNodeID &ID,
+    SCEVSignExtendExpr(const FoldingSetNodeIDRef ID,
                        const SCEV *op, const Type *ty);
 
   public:
@@ -187,7 +187,7 @@
     const SCEV *const *Operands;
     size_t NumOperands;
 
-    SCEVNAryExpr(const FoldingSetNodeID &ID,
+    SCEVNAryExpr(const FoldingSetNodeIDRef ID,
                  enum SCEVTypes T, const SCEV *const *O, size_t N)
       : SCEV(ID, T), Operands(O), NumOperands(N) {}
 
@@ -262,9 +262,8 @@
   ///
   class SCEVCommutativeExpr : public SCEVNAryExpr {
   protected:
-    SCEVCommutativeExpr(const FoldingSetNodeID &ID,
-                        enum SCEVTypes T,
-                        const SCEV *const *O, size_t N)
+    SCEVCommutativeExpr(const FoldingSetNodeIDRef ID,
+                        enum SCEVTypes T, const SCEV *const *O, size_t N)
       : SCEVNAryExpr(ID, T, O, N) {}
 
   public:
@@ -289,7 +288,7 @@
   class SCEVAddExpr : public SCEVCommutativeExpr {
     friend class ScalarEvolution;
 
-    SCEVAddExpr(const FoldingSetNodeID &ID,
+    SCEVAddExpr(const FoldingSetNodeIDRef ID,
                 const SCEV *const *O, size_t N)
       : SCEVCommutativeExpr(ID, scAddExpr, O, N) {
     }
@@ -317,7 +316,7 @@
   class SCEVMulExpr : public SCEVCommutativeExpr {
     friend class ScalarEvolution;
 
-    SCEVMulExpr(const FoldingSetNodeID &ID,
+    SCEVMulExpr(const FoldingSetNodeIDRef ID,
                 const SCEV *const *O, size_t N)
       : SCEVCommutativeExpr(ID, scMulExpr, O, N) {
     }
@@ -341,7 +340,7 @@
 
     const SCEV *LHS;
     const SCEV *RHS;
-    SCEVUDivExpr(const FoldingSetNodeID &ID, const SCEV *lhs, const SCEV *rhs)
+    SCEVUDivExpr(const FoldingSetNodeIDRef ID, const SCEV *lhs, const SCEV *rhs)
       : SCEV(ID, scUDivExpr), LHS(lhs), RHS(rhs) {}
 
   public:
@@ -391,7 +390,7 @@
 
     const Loop *L;
 
-    SCEVAddRecExpr(const FoldingSetNodeID &ID,
+    SCEVAddRecExpr(const FoldingSetNodeIDRef ID,
                    const SCEV *const *O, size_t N, const Loop *l)
       : SCEVNAryExpr(ID, scAddRecExpr, O, N), L(l) {
       for (size_t i = 0, e = NumOperands; i != e; ++i)
@@ -473,7 +472,7 @@
   class SCEVSMaxExpr : public SCEVCommutativeExpr {
     friend class ScalarEvolution;
 
-    SCEVSMaxExpr(const FoldingSetNodeID &ID,
+    SCEVSMaxExpr(const FoldingSetNodeIDRef ID,
                  const SCEV *const *O, size_t N)
       : SCEVCommutativeExpr(ID, scSMaxExpr, O, N) {
       // Max never overflows.
@@ -498,7 +497,7 @@
   class SCEVUMaxExpr : public SCEVCommutativeExpr {
     friend class ScalarEvolution;
 
-    SCEVUMaxExpr(const FoldingSetNodeID &ID,
+    SCEVUMaxExpr(const FoldingSetNodeIDRef ID,
                  const SCEV *const *O, size_t N)
       : SCEVCommutativeExpr(ID, scUMaxExpr, O, N) {
       // Max never overflows.
@@ -525,7 +524,7 @@
     friend class ScalarEvolution;
 
     Value *V;
-    SCEVUnknown(const FoldingSetNodeID &ID, Value *v) :
+    SCEVUnknown(const FoldingSetNodeIDRef ID, Value *v) :
       SCEV(ID, scUnknown), V(v) {}
 
   public:
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 12042c2..4c58131 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -141,7 +141,7 @@
 }
 
 SCEVCouldNotCompute::SCEVCouldNotCompute() :
-  SCEV(FoldingSetNodeID(), scCouldNotCompute) {}
+  SCEV(FoldingSetNodeIDRef(), scCouldNotCompute) {}
 
 bool SCEVCouldNotCompute::isLoopInvariant(const Loop *L) const {
   llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
@@ -178,7 +178,7 @@
   void *IP = 0;
   if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
   SCEV *S = SCEVAllocator.Allocate<SCEVConstant>();
-  new (S) SCEVConstant(ID, V);
+  new (S) SCEVConstant(ID.Intern(SCEVAllocator), V);
   UniqueSCEVs.InsertNode(S, IP);
   return S;
 }
@@ -199,7 +199,7 @@
   WriteAsOperand(OS, V, false);
 }
 
-SCEVCastExpr::SCEVCastExpr(const FoldingSetNodeID &ID,
+SCEVCastExpr::SCEVCastExpr(const FoldingSetNodeIDRef ID,
                            unsigned SCEVTy, const SCEV *op, const Type *ty)
   : SCEV(ID, SCEVTy), Op(op), Ty(ty) {}
 
@@ -211,7 +211,7 @@
   return Op->properlyDominates(BB, DT);
 }
 
-SCEVTruncateExpr::SCEVTruncateExpr(const FoldingSetNodeID &ID,
+SCEVTruncateExpr::SCEVTruncateExpr(const FoldingSetNodeIDRef ID,
                                    const SCEV *op, const Type *ty)
   : SCEVCastExpr(ID, scTruncate, op, ty) {
   assert((Op->getType()->isIntegerTy() || Op->getType()->isPointerTy()) &&
@@ -223,7 +223,7 @@
   OS << "(trunc " << *Op->getType() << " " << *Op << " to " << *Ty << ")";
 }
 
-SCEVZeroExtendExpr::SCEVZeroExtendExpr(const FoldingSetNodeID &ID,
+SCEVZeroExtendExpr::SCEVZeroExtendExpr(const FoldingSetNodeIDRef ID,
                                        const SCEV *op, const Type *ty)
   : SCEVCastExpr(ID, scZeroExtend, op, ty) {
   assert((Op->getType()->isIntegerTy() || Op->getType()->isPointerTy()) &&
@@ -235,7 +235,7 @@
   OS << "(zext " << *Op->getType() << " " << *Op << " to " << *Ty << ")";
 }
 
-SCEVSignExtendExpr::SCEVSignExtendExpr(const FoldingSetNodeID &ID,
+SCEVSignExtendExpr::SCEVSignExtendExpr(const FoldingSetNodeIDRef ID,
                                        const SCEV *op, const Type *ty)
   : SCEVCastExpr(ID, scSignExtend, op, ty) {
   assert((Op->getType()->isIntegerTy() || Op->getType()->isPointerTy()) &&
@@ -847,7 +847,7 @@
   // Recompute the insert position, as it may have been invalidated.
   if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
   SCEV *S = SCEVAllocator.Allocate<SCEVTruncateExpr>();
-  new (S) SCEVTruncateExpr(ID, Op, Ty);
+  new (S) SCEVTruncateExpr(ID.Intern(SCEVAllocator), Op, Ty);
   UniqueSCEVs.InsertNode(S, IP);
   return S;
 }
@@ -982,7 +982,7 @@
   // Recompute the insert position, as it may have been invalidated.
   if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
   SCEV *S = SCEVAllocator.Allocate<SCEVZeroExtendExpr>();
-  new (S) SCEVZeroExtendExpr(ID, Op, Ty);
+  new (S) SCEVZeroExtendExpr(ID.Intern(SCEVAllocator), Op, Ty);
   UniqueSCEVs.InsertNode(S, IP);
   return S;
 }
@@ -1117,7 +1117,7 @@
   // Recompute the insert position, as it may have been invalidated.
   if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
   SCEV *S = SCEVAllocator.Allocate<SCEVSignExtendExpr>();
-  new (S) SCEVSignExtendExpr(ID, Op, Ty);
+  new (S) SCEVSignExtendExpr(ID.Intern(SCEVAllocator), Op, Ty);
   UniqueSCEVs.InsertNode(S, IP);
   return S;
 }
@@ -1615,7 +1615,7 @@
     S = SCEVAllocator.Allocate<SCEVAddExpr>();
     const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
     std::uninitialized_copy(Ops.begin(), Ops.end(), O);
-    new (S) SCEVAddExpr(ID, O, Ops.size());
+    new (S) SCEVAddExpr(ID.Intern(SCEVAllocator), O, Ops.size());
     UniqueSCEVs.InsertNode(S, IP);
   }
   if (HasNUW) S->setHasNoUnsignedWrap(true);
@@ -1825,7 +1825,7 @@
     S = SCEVAllocator.Allocate<SCEVMulExpr>();
     const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
     std::uninitialized_copy(Ops.begin(), Ops.end(), O);
-    new (S) SCEVMulExpr(ID, O, Ops.size());
+    new (S) SCEVMulExpr(ID.Intern(SCEVAllocator), O, Ops.size());
     UniqueSCEVs.InsertNode(S, IP);
   }
   if (HasNUW) S->setHasNoUnsignedWrap(true);
@@ -1925,7 +1925,7 @@
   void *IP = 0;
   if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
   SCEV *S = SCEVAllocator.Allocate<SCEVUDivExpr>();
-  new (S) SCEVUDivExpr(ID, LHS, RHS);
+  new (S) SCEVUDivExpr(ID.Intern(SCEVAllocator), LHS, RHS);
   UniqueSCEVs.InsertNode(S, IP);
   return S;
 }
@@ -2036,7 +2036,7 @@
     S = SCEVAllocator.Allocate<SCEVAddRecExpr>();
     const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Operands.size());
     std::uninitialized_copy(Operands.begin(), Operands.end(), O);
-    new (S) SCEVAddRecExpr(ID, O, Operands.size(), L);
+    new (S) SCEVAddRecExpr(ID.Intern(SCEVAllocator), O, Operands.size(), L);
     UniqueSCEVs.InsertNode(S, IP);
   }
   if (HasNUW) S->setHasNoUnsignedWrap(true);
@@ -2138,7 +2138,7 @@
   SCEV *S = SCEVAllocator.Allocate<SCEVSMaxExpr>();
   const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
   std::uninitialized_copy(Ops.begin(), Ops.end(), O);
-  new (S) SCEVSMaxExpr(ID, O, Ops.size());
+  new (S) SCEVSMaxExpr(ID.Intern(SCEVAllocator), O, Ops.size());
   UniqueSCEVs.InsertNode(S, IP);
   return S;
 }
@@ -2237,7 +2237,7 @@
   SCEV *S = SCEVAllocator.Allocate<SCEVUMaxExpr>();
   const SCEV **O = SCEVAllocator.Allocate<const SCEV *>(Ops.size());
   std::uninitialized_copy(Ops.begin(), Ops.end(), O);
-  new (S) SCEVUMaxExpr(ID, O, Ops.size());
+  new (S) SCEVUMaxExpr(ID.Intern(SCEVAllocator), O, Ops.size());
   UniqueSCEVs.InsertNode(S, IP);
   return S;
 }
@@ -2300,7 +2300,7 @@
   void *IP = 0;
   if (const SCEV *S = UniqueSCEVs.FindNodeOrInsertPos(ID, IP)) return S;
   SCEV *S = SCEVAllocator.Allocate<SCEVUnknown>();
-  new (S) SCEVUnknown(ID, V);
+  new (S) SCEVUnknown(ID.Intern(SCEVAllocator), V);
   UniqueSCEVs.InsertNode(S, IP);
   return S;
 }
diff --git a/lib/Support/FoldingSet.cpp b/lib/Support/FoldingSet.cpp
index 954dc77..3f467fe 100644
--- a/lib/Support/FoldingSet.cpp
+++ b/lib/Support/FoldingSet.cpp
@@ -15,6 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/FoldingSet.h"
+#include "llvm/Support/Allocator.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include <cassert>
@@ -130,6 +131,15 @@
   return memcmp(&Bits[0], &RHS.Bits[0], Bits.size()*sizeof(Bits[0])) == 0;
 }
 
+/// Intern - Copy this node's data to a memory region allocated from the
+/// given allocator and return a FoldingSetNodeIDRef describing the
+/// interned data.
+FoldingSetNodeIDRef
+FoldingSetNodeID::Intern(BumpPtrAllocator &Allocator) const {
+  unsigned *New = Allocator.Allocate<unsigned>(Bits.size());
+  std::uninitialized_copy(Bits.begin(), Bits.end(), New);
+  return FoldingSetNodeIDRef(New, Bits.size());
+}
 
 //===----------------------------------------------------------------------===//
 /// Helper functions for FoldingSetImpl.