[SmallPtrSet] Add iterator epoch tracking.

This will detect invalid iterators when ABI breaking checks are enabled.

llvm-svn: 315746

llvm/include/llvm/ADT/SmallPtrSet.h

@@ -15,6 +15,7 @@
 #ifndef LLVM_ADT_SMALLPTRSET_H
 #define LLVM_ADT_SMALLPTRSET_H
 
+#include "llvm/ADT/EpochTracker.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/ReverseIteration.h"
 #include "llvm/Support/type_traits.h"
@@ -46,7 +47,7 @@ namespace llvm {
 /// (-2), to allow deletion.  The hash table is resized when the table is 3/4 or
 /// more.  When this happens, the table is doubled in size.
 ///
-class SmallPtrSetImplBase {
+class SmallPtrSetImplBase : public DebugEpochBase {
   friend class SmallPtrSetIteratorImpl;
 
 protected:
@@ -92,6 +93,7 @@ public:
   size_type size() const { return NumNonEmpty - NumTombstones; }
 
   void clear() {
+    incrementEpoch();
     // If the capacity of the array is huge, and the # elements used is small,
     // shrink the array.
     if (!isSmall()) {
@@ -138,12 +140,14 @@ protected:
       if (LastTombstone != nullptr) {
         *LastTombstone = Ptr;
         --NumTombstones;
+        incrementEpoch();
         return std::make_pair(LastTombstone, true);
       }
 
       // Nope, there isn't.  If we stay small, just 'pushback' now.
       if (NumNonEmpty < CurArraySize) {
         SmallArray[NumNonEmpty++] = Ptr;
+        incrementEpoch();
         return std::make_pair(SmallArray + (NumNonEmpty - 1), true);
       }
       // Otherwise, hit the big set case, which will call grow.
@@ -259,8 +263,9 @@ protected:
 };
 
 /// SmallPtrSetIterator - This implements a const_iterator for SmallPtrSet.
-template<typename PtrTy>
-class SmallPtrSetIterator : public SmallPtrSetIteratorImpl {
+template <typename PtrTy>
+class SmallPtrSetIterator : public SmallPtrSetIteratorImpl,
+                            DebugEpochBase::HandleBase {
   using PtrTraits = PointerLikeTypeTraits<PtrTy>;
 
 public:
@@ -270,12 +275,14 @@ public:
   using difference_type = std::ptrdiff_t;
   using iterator_category = std::forward_iterator_tag;
 
-  explicit SmallPtrSetIterator(const void *const *BP, const void *const *E)
-    : SmallPtrSetIteratorImpl(BP, E) {}
+  explicit SmallPtrSetIterator(const void *const *BP, const void *const *E,
+                               const DebugEpochBase &Epoch)
+      : SmallPtrSetIteratorImpl(BP, E), DebugEpochBase::HandleBase(&Epoch) {}
 
   // Most methods provided by baseclass.
 
   const PtrTy operator*() const {
+    assert(isHandleInSync() && "invalid iterator access!");
     if (shouldReverseIterate()) {
       assert(Bucket > End);
       return PtrTraits::getFromVoidPointer(const_cast<void *>(Bucket[-1]));
@@ -285,6 +292,7 @@ public:
   }
 
   inline SmallPtrSetIterator& operator++() {          // Preincrement
+    assert(isHandleInSync() && "invalid iterator access!");
     if (shouldReverseIterate()) {
       --Bucket;
       RetreatIfNotValid();
@@ -397,8 +405,8 @@ private:
   /// Create an iterator that dereferences to same place as the given pointer.
   iterator makeIterator(const void *const *P) const {
     if (shouldReverseIterate())
-      return iterator(P == EndPointer() ? CurArray : P + 1, CurArray);
-    return iterator(P, EndPointer());
+      return iterator(P == EndPointer() ? CurArray : P + 1, CurArray, *this);
+    return iterator(P, EndPointer(), *this);
   }
 };
 

llvm/lib/Support/SmallPtrSet.cpp

@@ -61,6 +61,7 @@ SmallPtrSetImplBase::insert_imp_big(const void *Ptr) {
   else
     ++NumNonEmpty; // Track density.
   *Bucket = Ptr;
+  incrementEpoch();
   return std::make_pair(Bucket, true);
 }