[llvm] r231050 - Revert "[ADT] fail-fast iterators for DenseMap"
Sanjoy Das
sanjoy at playingwithpointers.com
Mon Mar 2 17:59:38 PST 2015
Author: sanjoy
Date: Mon Mar 2 19:59:38 2015
New Revision: 231050
URL: http://llvm.org/viewvc/llvm-project?rev=231050&view=rev
Log:
Revert "[ADT] fail-fast iterators for DenseMap"
This reverts commit r231035. It breaks clang.
Removed:
llvm/trunk/include/llvm/ADT/EpochTracker.h
Modified:
llvm/trunk/include/llvm/ADT/DenseMap.h
Modified: llvm/trunk/include/llvm/ADT/DenseMap.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/DenseMap.h?rev=231050&r1=231049&r2=231050&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/DenseMap.h (original)
+++ llvm/trunk/include/llvm/ADT/DenseMap.h Mon Mar 2 19:59:38 2015
@@ -15,7 +15,6 @@
#define LLVM_ADT_DENSEMAP_H
#include "llvm/ADT/DenseMapInfo.h"
-#include "llvm/ADT/EpochTracker.h"
#include "llvm/Support/AlignOf.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/MathExtras.h"
@@ -51,7 +50,7 @@ class DenseMapIterator;
template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT,
typename BucketT>
-class DenseMapBase : public DebugEpochBase {
+class DenseMapBase {
public:
typedef unsigned size_type;
typedef KeyT key_type;
@@ -63,17 +62,16 @@ public:
const_iterator;
inline iterator begin() {
// When the map is empty, avoid the overhead of AdvancePastEmptyBuckets().
- return empty() ? end() : iterator(getBuckets(), getBucketsEnd(), *this);
+ return empty() ? end() : iterator(getBuckets(), getBucketsEnd());
}
inline iterator end() {
- return iterator(getBucketsEnd(), getBucketsEnd(), *this, true);
+ return iterator(getBucketsEnd(), getBucketsEnd(), true);
}
inline const_iterator begin() const {
- return empty() ? end()
- : const_iterator(getBuckets(), getBucketsEnd(), *this);
+ return empty() ? end() : const_iterator(getBuckets(), getBucketsEnd());
}
inline const_iterator end() const {
- return const_iterator(getBucketsEnd(), getBucketsEnd(), *this, true);
+ return const_iterator(getBucketsEnd(), getBucketsEnd(), true);
}
bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const {
@@ -83,13 +81,11 @@ public:
/// Grow the densemap so that it has at least Size buckets. Does not shrink
void resize(size_type Size) {
- incrementEpoch();
if (Size > getNumBuckets())
grow(Size);
}
void clear() {
- incrementEpoch();
if (getNumEntries() == 0 && getNumTombstones() == 0) return;
// If the capacity of the array is huge, and the # elements used is small,
@@ -122,13 +118,13 @@ public:
iterator find(const KeyT &Val) {
BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
- return iterator(TheBucket, getBucketsEnd(), *this, true);
+ return iterator(TheBucket, getBucketsEnd(), true);
return end();
}
const_iterator find(const KeyT &Val) const {
const BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
- return const_iterator(TheBucket, getBucketsEnd(), *this, true);
+ return const_iterator(TheBucket, getBucketsEnd(), true);
return end();
}
@@ -141,14 +137,14 @@ public:
iterator find_as(const LookupKeyT &Val) {
BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
- return iterator(TheBucket, getBucketsEnd(), *this, true);
+ return iterator(TheBucket, getBucketsEnd(), true);
return end();
}
template<class LookupKeyT>
const_iterator find_as(const LookupKeyT &Val) const {
const BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
- return const_iterator(TheBucket, getBucketsEnd(), *this, true);
+ return const_iterator(TheBucket, getBucketsEnd(), true);
return end();
}
@@ -167,13 +163,12 @@ public:
std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
BucketT *TheBucket;
if (LookupBucketFor(KV.first, TheBucket))
- return std::make_pair(iterator(TheBucket, getBucketsEnd(), *this, true),
+ return std::make_pair(iterator(TheBucket, getBucketsEnd(), true),
false); // Already in map.
// Otherwise, insert the new element.
TheBucket = InsertIntoBucket(KV.first, KV.second, TheBucket);
- return std::make_pair(iterator(TheBucket, getBucketsEnd(), *this, true),
- true);
+ return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), true);
}
// Inserts key,value pair into the map if the key isn't already in the map.
@@ -182,15 +177,14 @@ public:
std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) {
BucketT *TheBucket;
if (LookupBucketFor(KV.first, TheBucket))
- return std::make_pair(iterator(TheBucket, getBucketsEnd(), *this, true),
+ return std::make_pair(iterator(TheBucket, getBucketsEnd(), true),
false); // Already in map.
-
+
// Otherwise, insert the new element.
TheBucket = InsertIntoBucket(std::move(KV.first),
std::move(KV.second),
TheBucket);
- return std::make_pair(iterator(TheBucket, getBucketsEnd(), *this, true),
- true);
+ return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), true);
}
/// insert - Range insertion of pairs.
@@ -437,8 +431,6 @@ private:
}
BucketT *InsertIntoBucketImpl(const KeyT &Key, BucketT *TheBucket) {
- incrementEpoch();
-
// If the load of the hash table is more than 3/4, or if fewer than 1/8 of
// the buckets are empty (meaning that many are filled with tombstones),
// grow the table.
@@ -995,7 +987,7 @@ private:
template <typename KeyT, typename ValueT, typename KeyInfoT, typename Bucket,
bool IsConst>
-class DenseMapIterator : DebugEpochBase::HandleBase {
+class DenseMapIterator {
typedef DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true> ConstIterator;
friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>;
@@ -1011,10 +1003,8 @@ private:
public:
DenseMapIterator() : Ptr(nullptr), End(nullptr) {}
- DenseMapIterator(pointer Pos, pointer E, const DebugEpochBase &Epoch,
- bool NoAdvance = false)
- : DebugEpochBase::HandleBase(&Epoch), Ptr(Pos), End(E) {
- assert(isHandleInSync() && "invalid construction!");
+ DenseMapIterator(pointer Pos, pointer E, bool NoAdvance = false)
+ : Ptr(Pos), End(E) {
if (!NoAdvance) AdvancePastEmptyBuckets();
}
@@ -1023,14 +1013,12 @@ public:
// Otherwise this is a copy constructor for iterator.
DenseMapIterator(
const DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, false> &I)
- : DebugEpochBase::HandleBase(I), Ptr(I.Ptr), End(I.End) {}
+ : Ptr(I.Ptr), End(I.End) {}
reference operator*() const {
- assert(isHandleInSync() && "invalid iterator access!");
return *Ptr;
}
pointer operator->() const {
- assert(isHandleInSync() && "invalid iterator access!");
return Ptr;
}
@@ -1042,13 +1030,11 @@ public:
}
inline DenseMapIterator& operator++() { // Preincrement
- assert(isHandleInSync() && "invalid iterator access!");
++Ptr;
AdvancePastEmptyBuckets();
return *this;
}
DenseMapIterator operator++(int) { // Postincrement
- assert(isHandleInSync() && "invalid iterator access!");
DenseMapIterator tmp = *this; ++*this; return tmp;
}
Removed: llvm/trunk/include/llvm/ADT/EpochTracker.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/EpochTracker.h?rev=231049&view=auto
==============================================================================
--- llvm/trunk/include/llvm/ADT/EpochTracker.h (original)
+++ llvm/trunk/include/llvm/ADT/EpochTracker.h (removed)
@@ -1,91 +0,0 @@
-//===- llvm/ADT/EpochTracker.h - ADT epoch tracking --------------*- C++ -*-==//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file defines the DebugEpochBase and DebugEpochBase::HandleBase classes.
-// These can be used to write iterators that are fail-fast when LLVM is built
-// with asserts enabled.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_ADT_EPOCH_TRACKER_H
-#define LLVM_ADT_EPOCH_TRACKER_H
-
-#include <cstdint>
-
-namespace llvm {
-
-#ifdef NDEBUG
-
-class DebugEpochBase {
-public:
- void incrementEpoch() {}
-
- class HandleBase {
- public:
- HandleBase() {}
- explicit HandleBase(const DebugEpochBase *) {}
- bool isHandleInSync() { return true; }
- };
-};
-
-#else
-
-/// \brief A base class for data structure classes wishing to make iterators
-/// ("handles") pointing into themselves fail-fast. When building without
-/// asserts, this class is empty and does nothing.
-///
-/// DebugEpochBase does not by itself track handles pointing into itself. The
-/// expectation is that routines touching the handles will poll on
-/// isHandleInSync at appropriate points to assert that the handle they're using
-/// is still valid.
-///
-class DebugEpochBase {
- uint64_t Epoch;
-
-public:
- DebugEpochBase() : Epoch(0) {}
-
- /// \brief Calling incrementEpoch invalidates all handles pointing into the
- /// calling instance.
- void incrementEpoch() { ++Epoch; }
-
- /// \brief The destructor calls incrementEpoch to make use-after-free bugs
- /// more likely to crash deterministically.
- ~DebugEpochBase() { incrementEpoch(); }
-
- /// \brief A base class for iterator classes ("handles") that wish to poll for
- /// iterator invalidating modifications in the underlying data structure.
- /// When LLVM is built without asserts, this class is empty and does nothing.
- ///
- /// HandleBase does not track the parent data structure by itself. It expects
- /// the routines modifying the data structure to call incrementEpoch when they
- /// make an iterator-invalidating modification.
- ///
- class HandleBase {
- const uint64_t *EpochAddress;
- uint64_t EpochAtCreation;
-
- public:
- HandleBase() : EpochAddress(nullptr), EpochAtCreation(UINT64_MAX) {}
-
- explicit HandleBase(const DebugEpochBase *Parent)
- : EpochAddress(&Parent->Epoch), EpochAtCreation(Parent->Epoch) {}
-
- /// \brief Returns true if the DebugEpochBase this Handle is linked to has
- /// not called incrementEpoch on itself since the creation of this
- /// HandleBase instance.
- bool isHandleInSync() const { return *EpochAddress == EpochAtCreation; }
- };
-};
-
-#endif
-
-} // namespace llvm
-
-#endif
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