Fold the useful features of alist and alist_node into ilist, and

a new ilist_node class, and remove them. Unlike alist_node,
ilist_node doesn't attempt to manage storage itself, so it avoids
the associated problems, including being opaque in gdb.

Adjust the Recycler class so that it doesn't depend on alist_node.
Also, change it to use explicit Size and Align parameters, allowing
it to work when the largest-sized node doesn't have the greatest
alignment requirement.

Change MachineInstr's MachineMemOperand list from a pool-backed
alist to a std::list for now.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54146 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 54 insertions, 38 deletions

diff --git a/include/llvm/Support/Recycler.h b/include/llvm/Support/Recycler.h
index 4750a6d..3f235b6 100644
--- a/include/llvm/Support/Recycler.h
+++ b/include/llvm/Support/Recycler.h
@@ -15,62 +15,81 @@
 #ifndef LLVM_SUPPORT_RECYCLER_H
 #define LLVM_SUPPORT_RECYCLER_H
 
-#include "llvm/ADT/alist_node.h"
+#include "llvm/ADT/ilist.h"
+#include "llvm/Support/AlignOf.h"
+#include <cassert>
 
 namespace llvm {
 
 /// PrintRecyclingAllocatorStats - Helper for RecyclingAllocator for
 /// printing statistics.
 ///
-void PrintRecyclerStats(size_t LargestTypeSize, size_t FreeListSize);
+void PrintRecyclerStats(size_t Size, size_t Align, size_t FreeListSize);
+
+/// RecyclerStruct - Implementation detail for Recycler. This is a
+/// class that the recycler imposes on free'd memory to carve out
+/// next/prev pointers.
+struct RecyclerStruct {
+  RecyclerStruct *Prev, *Next;
+};
+
+template<>
+struct ilist_traits<RecyclerStruct> : ilist_default_traits<RecyclerStruct> {
+  static RecyclerStruct *getPrev(const RecyclerStruct *t) { return t->Prev; }
+  static RecyclerStruct *getNext(const RecyclerStruct *t) { return t->Next; }
+  static void setPrev(RecyclerStruct *t, RecyclerStruct *p) { t->Prev = p; }
+  static void setNext(RecyclerStruct *t, RecyclerStruct *n) { t->Next = n; }
+
+  mutable RecyclerStruct Sentinel;
+  RecyclerStruct *createSentinel() const {
+    return &Sentinel;
+  }
+  static void destroySentinel(RecyclerStruct *) {}
+
+  static void deleteNode(RecyclerStruct *) {
+    assert(0 && "Recycler's ilist_traits shouldn't see a deleteNode call!");
+  }
+};
 
 /// Recycler - This class manages a linked-list of deallocated nodes
 /// and facilitates reusing deallocated memory in place of allocating
-/// new memory. The objects it allocates are stored in alist_node
-/// containers, so they may be used in alists.
+/// new memory.
 ///
-template<class T, class LargestT = T>
+template<class T, size_t Size = sizeof(T), size_t Align = AlignOf<T>::Alignment>
 class Recycler {
-  typedef alist_node<T, LargestT> NodeTy;
-
-  /// FreeListTraits - ilist traits for FreeList.
-  ///
-  struct FreeListTraits : ilist_traits<alist_node<T, LargestT> > {
-    NodeTy &getSentinel() { return this->Sentinel; }
-  };
-
   /// FreeList - Doubly-linked list of nodes that have deleted contents and
   /// are not in active use.
   ///
-  iplist<NodeTy, FreeListTraits> FreeList;
-
-  /// CreateNewNode - Allocate a new node object and initialize its
-  /// prev and next pointers to 0.
-  ///
-  template<class AllocatorType>
-  NodeTy *CreateNewNode(AllocatorType &Allocator) {
-    // Note that we're calling new on the *node*, to initialize its
-    // Next/Prev pointers, not new on the end-user object.
-    return new (Allocator.Allocate<NodeTy>()) NodeTy();
-  }
+  iplist<RecyclerStruct> FreeList;
 
 public:
-  ~Recycler() { assert(FreeList.empty()); }
+  ~Recycler() {
+    // If this fails, either the callee has lost track of some allocation,
+    // or the callee isn't tracking allocations and should just call
+    // clear() before deleting the Recycler.
+    assert(FreeList.empty() && "Non-empty recycler deleted!");
+  }
 
+  /// clear - Release all the tracked allocations to the allocator. The
+  /// recycler must be free of any tracked allocations before being
+  /// deleted; calling clear is one way to ensure this.
   template<class AllocatorType>
   void clear(AllocatorType &Allocator) {
-    while (!FreeList.empty())
-      Allocator.Deallocate(FreeList.remove(FreeList.begin()));
+    while (!FreeList.empty()) {
+      T *t = reinterpret_cast<T *>(FreeList.remove(FreeList.begin()));
+      Allocator.Deallocate(t);
+    }
   }
 
   template<class SubClass, class AllocatorType>
   SubClass *Allocate(AllocatorType &Allocator) {
-    NodeTy *N = !FreeList.empty() ?
-                FreeList.remove(FreeList.front()) :
-                CreateNewNode(Allocator);
-    assert(N->getPrev() == 0);
-    assert(N->getNext() == 0);
-    return N->getElement((SubClass*)0);
+    assert(sizeof(SubClass) <= Size &&
+           "Recycler allocation size is less than object size!");
+    assert(AlignOf<SubClass>::Alignment <= Align &&
+           "Recycler allocation alignment is less than object alignment!");
+    return !FreeList.empty() ?
+           reinterpret_cast<SubClass *>(FreeList.remove(FreeList.begin())) :
+           static_cast<SubClass *>(Allocator.Allocate(Size, Align));
   }
 
   template<class AllocatorType>
@@ -80,14 +99,11 @@ public:
 
   template<class SubClass, class AllocatorType>
   void Deallocate(AllocatorType & /*Allocator*/, SubClass* Element) {
-    NodeTy *N = NodeTy::getNode(Element);
-    assert(N->getPrev() == 0);
-    assert(N->getNext() == 0);
-    FreeList.push_front(N);
+    FreeList.push_front(reinterpret_cast<RecyclerStruct *>(Element));
   }
 
   void PrintStats() {
-    PrintRecyclerStats(sizeof(LargestT), FreeList.size());
+    PrintRecyclerStats(Size, Align, FreeList.size());
   }
 };