[llvm] r278974 - ADT: Remove UB in ilist (and use a circular linked list)
Diana Picus via llvm-commits
llvm-commits at lists.llvm.org
Fri Aug 19 04:26:37 PDT 2016
Finally got hold of a machine to run this on. It's currently in
progress, I'll let you know how it goes.
On 19 August 2016 at 13:27, Diana Picus <diana.picus at linaro.org> wrote:
> Hi Duncan,
>
> Sorry about that, our machines are currently a bit busy bisecting
> another bot failure / running tests for the release candidate. As soon
> as those are done, I'll give it a run.
>
> Thanks,
> Diana
>
> On 19 August 2016 at 03:14, Duncan P. N. Exon Smith
> <dexonsmith at apple.com> wrote:
>> Hi Diana, any update? Are you able to test pre-commit, or should I just commit and let the bots do the work?
>>
>>> On 2016-Aug-18, at 11:09, Duncan P. N. Exon Smith via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>>>
>>> Hi Diana,
>>>
>>> I fixed PR29035 in r279104. Are you able to test that revision with r278974 cherry-picked on top to be sure the assertion isn't firing elsewhere?
>>>
>>> Thanks,
>>> Duncan
>>>
>>>> On 2016-Aug-18, at 06:19, Duncan Exon Smith via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>>>>
>>>> Please attach the reproducer mentioned in the log message:
>>>>
>>>> clang-4.0: note: diagnostic msg: PLEASE submit a bug report to http://llvm.org/bugs/ and include the crash backtrace, preprocessed source, and associated run script.
>>>> clang-4.0: note: diagnostic msg:
>>>> ********************
>>>> PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
>>>> Preprocessed source(s) and associated run script(s) are located at:
>>>> clang-4.0: note: diagnostic msg: /tmp/gtest-all-78e9e5.cpp
>>>> clang-4.0: note: diagnostic msg: /tmp/gtest-all-78e9e5.sh
>>>> clang-4.0: note: diagnostic msg:
>>>> ********************
>>>>
>>>> -- dpnes
>>>>
>>>> On Aug 18, 2016, at 04:32, Diana Picus <diana.picus at linaro.org> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I had to revert this because it was breaking some of the bots. I also
>>>>> reverted r279012 because it was in the way (and it looked like a fixup
>>>>> for this revision anyway).
>>>>> I've attached a log of the failure to this bug:
>>>>> https://llvm.org/bugs/show_bug.cgi?id=29035
>>>>> Please let me know if you need anything else to debug this.
>>>>>
>>>>> Thanks,
>>>>> Diana
>>>>>
>>>>>
>>>>>
>>>>> On 17 August 2016 at 23:44, Duncan P. N. Exon Smith via llvm-commits
>>>>> <llvm-commits at lists.llvm.org> wrote:
>>>>>> Author: dexonsmith
>>>>>> Date: Wed Aug 17 15:44:33 2016
>>>>>> New Revision: 278974
>>>>>>
>>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=278974&view=rev
>>>>>> Log:
>>>>>> ADT: Remove UB in ilist (and use a circular linked list)
>>>>>>
>>>>>> This removes the undefined behaviour (UB) in ilist/ilist_node/etc.,
>>>>>> mainly by removing (gutting) the ilist_sentinel_traits customization
>>>>>> point and canonicalizing on a single, efficient memory layout. This
>>>>>> fixes PR26753.
>>>>>>
>>>>>> The new ilist is a doubly-linked circular list.
>>>>>> - ilist_node_base has two ilist_node_base*: Next and Prev. Size-of: two
>>>>>> pointers.
>>>>>> - ilist_node<T> (size-of: two pointers) is a type-safe wrapper around
>>>>>> ilist_node_base.
>>>>>> - ilist_iterator<T> (size-of: two pointers) operates on an
>>>>>> ilist_node<T>*, and downcasts to T* on dereference.
>>>>>> - ilist_sentinel<T> (size-of: two pointers) is a wrapper around
>>>>>> ilist_node<T> that has some extra API for list management.
>>>>>> - ilist<T> (size-of: two pointers) has an ilist_sentinel<T>, whose
>>>>>> address is returned for end().
>>>>>>
>>>>>> The new memory layout matches ilist_half_embedded_sentinel_traits<T>
>>>>>> exactly. The Head pointer that previously lived in ilist<T> is
>>>>>> effectively glued to the ilist_half_node<T> that lived in
>>>>>> ilist_half_embedded_sentinel_traits<T>, becoming the Next and Prev in
>>>>>> the ilist_sentinel_node<T>, respectively. sizeof(ilist<T>) is now the
>>>>>> size of two pointers, and there is never any additional storage for a
>>>>>> sentinel.
>>>>>>
>>>>>> This is a much simpler design for a doubly-linked list, removing most of
>>>>>> the corner cases of list manipulation (add, remove, etc.). In follow-up
>>>>>> commits, I intend to move as many algorithms as possible into a
>>>>>> non-templated base class (ilist_base) to reduce code size.
>>>>>>
>>>>>> Moreover, this fixes the UB in ilist_iterator/getNext/getPrev
>>>>>> operations. Previously, ilist_iterator<T> operated on a T*, even when
>>>>>> the sentinel was not of type T (i.e., ilist_embedded_sentinel_traits and
>>>>>> ilist_half_embedded_sentinel_traits). This added UB to all operations
>>>>>> involving end(). Now, ilist_iterator<T> operates on an ilist_node<T>*,
>>>>>> and only downcasts when the full type is guaranteed to be T*.
>>>>>>
>>>>>> What did we lose? There used to be a crash (in some configurations) on
>>>>>> ++end(). Curiously (via UB), ++end() would return begin() for users of
>>>>>> ilist_half_embedded_sentinel_traits<T>, but otherwise ++end() would
>>>>>> cause a nice dependable nullptr dereference, crashing instead of a
>>>>>> possible infinite loop. Options:
>>>>>> 1. Lose that behaviour.
>>>>>> 2. Keep it, by stealing a bit from Prev in asserts builds.
>>>>>> 3. Crash on dereference instead, using the same technique.
>>>>>>
>>>>>> Hans convinced me (because of the number of problems this and r278532
>>>>>> exposed on Windows) that we really need some assertion here, at least in
>>>>>> the short term. I've opted for #3 since I think it catches more bugs.
>>>>>>
>>>>>> I added only a couple of unit tests to root out specific bugs I hit
>>>>>> during bring-up, but otherwise this is tested implicitly via the
>>>>>> extensive usage throughout LLVM.
>>>>>>
>>>>>> Planned follow-ups:
>>>>>> - Remove ilist_*sentinel_traits<T>. Here I've just gutted them to
>>>>>> prevent build failures in sub-projects. Once I stop referring to them
>>>>>> in sub-projects, I'll come back and delete them.
>>>>>> - Add ilist_base and move algorithms there.
>>>>>> - Check and fix move construction and assignment.
>>>>>>
>>>>>> Eventually, there are other interesting directions:
>>>>>> - Rewrite reverse iterators, so that rbegin().getNodePtr()==&*rbegin().
>>>>>> This allows much simpler logic when erasing elements during a reverse
>>>>>> traversal.
>>>>>> - Remove ilist_traits::createNode, by deleting the remaining API that
>>>>>> creates nodes. Intrusive lists shouldn't be creating nodes
>>>>>> themselves.
>>>>>> - Remove ilist_traits::deleteNode, by (1) asserting that lists are empty
>>>>>> on destruction and (2) changing API that calls it to take a Deleter
>>>>>> functor (intrusive lists shouldn't be in the memory management
>>>>>> business).
>>>>>> - Reconfigure the remaining callback traits (addNodeToList, etc.) to be
>>>>>> higher-level, pulling out a simple_ilist<T> that is much easier to
>>>>>> read and understand.
>>>>>> - Allow tags (e.g., ilist_node<T,tag1> and ilist_node<T,tag2>) so that T
>>>>>> can be a member of multiple intrusive lists.
>>>>>>
>>>>>> Modified:
>>>>>> llvm/trunk/include/llvm/ADT/ilist.h
>>>>>> llvm/trunk/include/llvm/ADT/ilist_node.h
>>>>>> llvm/trunk/unittests/ADT/ilistTest.cpp
>>>>>>
>>>>>> Modified: llvm/trunk/include/llvm/ADT/ilist.h
>>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/ilist.h?rev=278974&r1=278973&r2=278974&view=diff
>>>>>> ==============================================================================
>>>>>> --- llvm/trunk/include/llvm/ADT/ilist.h (original)
>>>>>> +++ llvm/trunk/include/llvm/ADT/ilist.h Wed Aug 17 15:44:33 2016
>>>>>> @@ -15,17 +15,16 @@
>>>>>> // replacement does not provide a constant time size() method, so be careful to
>>>>>> // use empty() when you really want to know if it's empty.
>>>>>> //
>>>>>> -// The ilist class is implemented by allocating a 'tail' node when the list is
>>>>>> -// created (using ilist_traits<>::createSentinel()). This tail node is
>>>>>> -// absolutely required because the user must be able to compute end()-1. Because
>>>>>> -// of this, users of the direct next/prev links will see an extra link on the
>>>>>> -// end of the list, which should be ignored.
>>>>>> +// The ilist class is implemented as a circular list. The list itself contains
>>>>>> +// a sentinel node, whose Next points at begin() and whose Prev points at
>>>>>> +// rbegin(). The sentinel node itself serves as end() and rend().
>>>>>> //
>>>>>> //===----------------------------------------------------------------------===//
>>>>>>
>>>>>> #ifndef LLVM_ADT_ILIST_H
>>>>>> #define LLVM_ADT_ILIST_H
>>>>>>
>>>>>> +#include "llvm/ADT/ilist_node.h"
>>>>>> #include "llvm/Support/Compiler.h"
>>>>>> #include <algorithm>
>>>>>> #include <cassert>
>>>>>> @@ -38,37 +37,42 @@ namespace llvm {
>>>>>> template<typename NodeTy, typename Traits> class iplist;
>>>>>> template<typename NodeTy> class ilist_iterator;
>>>>>>
>>>>>> -/// An access class for next/prev on ilist_nodes.
>>>>>> +/// An access class for ilist_node private API.
>>>>>> ///
>>>>>> /// This gives access to the private parts of ilist nodes. Nodes for an ilist
>>>>>> /// should friend this class if they inherit privately from ilist_node.
>>>>>> ///
>>>>>> -/// It's strongly discouraged to *use* this class outside of ilist
>>>>>> +/// It's strongly discouraged to *use* this class outside of the ilist
>>>>>> /// implementation.
>>>>>> struct ilist_node_access {
>>>>>> - template <typename NodeTy> static NodeTy *getPrev(NodeTy *N) {
>>>>>> + template <typename T> static ilist_node<T> *getNodePtr(T *N) { return N; }
>>>>>> + template <typename T> static const ilist_node<T> *getNodePtr(const T *N) {
>>>>>> + return N;
>>>>>> + }
>>>>>> +
>>>>>> + template <typename T> static ilist_node<T> *getPrev(ilist_node<T> *N) {
>>>>>> return N->getPrev();
>>>>>> }
>>>>>> - template <typename NodeTy> static NodeTy *getNext(NodeTy *N) {
>>>>>> + template <typename T> static ilist_node<T> *getNext(ilist_node<T> *N) {
>>>>>> return N->getNext();
>>>>>> }
>>>>>> - template <typename NodeTy> static const NodeTy *getPrev(const NodeTy *N) {
>>>>>> + template <typename T> static const ilist_node<T> *getPrev(const ilist_node<T> *N) {
>>>>>> return N->getPrev();
>>>>>> }
>>>>>> - template <typename NodeTy> static const NodeTy *getNext(const NodeTy *N) {
>>>>>> + template <typename T> static const ilist_node<T> *getNext(const ilist_node<T> *N) {
>>>>>> return N->getNext();
>>>>>> }
>>>>>>
>>>>>> - template <typename NodeTy> static void setPrev(NodeTy *N, NodeTy *Prev) {
>>>>>> + template <typename T> static void setPrev(ilist_node<T> *N, ilist_node<T> *Prev) {
>>>>>> N->setPrev(Prev);
>>>>>> }
>>>>>> - template <typename NodeTy> static void setNext(NodeTy *N, NodeTy *Next) {
>>>>>> + template <typename T> static void setNext(ilist_node<T> *N, ilist_node<T> *Next) {
>>>>>> N->setNext(Next);
>>>>>> }
>>>>>> - template <typename NodeTy> static void setPrev(NodeTy *N, std::nullptr_t) {
>>>>>> + template <typename T> static void setPrev(ilist_node<T> *N, std::nullptr_t) {
>>>>>> N->setPrev(nullptr);
>>>>>> }
>>>>>> - template <typename NodeTy> static void setNext(NodeTy *N, std::nullptr_t) {
>>>>>> + template <typename T> static void setNext(ilist_node<T> *N, std::nullptr_t) {
>>>>>> N->setNext(nullptr);
>>>>>> }
>>>>>> };
>>>>>> @@ -93,111 +97,31 @@ template <class TraitsT, class NodeT> st
>>>>>> static const bool value = sizeof(hasGetNext<TraitsT>(nullptr)) == sizeof(Yes);
>>>>>> };
>>>>>>
>>>>>> -} // end namespace ilist_detail
>>>>>> -
>>>>>> -template<typename NodeTy>
>>>>>> -struct ilist_traits;
>>>>>> -
>>>>>> -/// ilist_sentinel_traits - A fragment for template traits for intrusive list
>>>>>> -/// that provides default sentinel implementations for common operations.
>>>>>> -///
>>>>>> -/// ilist_sentinel_traits implements a lazy dynamic sentinel allocation
>>>>>> -/// strategy. The sentinel is stored in the prev field of ilist's Head.
>>>>>> -///
>>>>>> -template<typename NodeTy>
>>>>>> -struct ilist_sentinel_traits {
>>>>>> - /// createSentinel - create the dynamic sentinel
>>>>>> - static NodeTy *createSentinel() { return new NodeTy(); }
>>>>>> -
>>>>>> - /// destroySentinel - deallocate the dynamic sentinel
>>>>>> - static void destroySentinel(NodeTy *N) { delete N; }
>>>>>> -
>>>>>> - /// provideInitialHead - when constructing an ilist, provide a starting
>>>>>> - /// value for its Head
>>>>>> - /// @return null node to indicate that it needs to be allocated later
>>>>>> - static NodeTy *provideInitialHead() { return nullptr; }
>>>>>> -
>>>>>> - /// ensureHead - make sure that Head is either already
>>>>>> - /// initialized or assigned a fresh sentinel
>>>>>> - /// @return the sentinel
>>>>>> - static NodeTy *ensureHead(NodeTy *&Head) {
>>>>>> - if (!Head) {
>>>>>> - Head = ilist_traits<NodeTy>::createSentinel();
>>>>>> - ilist_traits<NodeTy>::noteHead(Head, Head);
>>>>>> - ilist_node_access::setNext(Head, nullptr);
>>>>>> - return Head;
>>>>>> - }
>>>>>> - return ilist_node_access::getPrev(Head);
>>>>>> - }
>>>>>> -
>>>>>> - /// noteHead - stash the sentinel into its default location
>>>>>> - static void noteHead(NodeTy *NewHead, NodeTy *Sentinel) {
>>>>>> - ilist_node_access::setPrev(NewHead, Sentinel);
>>>>>> - }
>>>>>> -};
>>>>>> -
>>>>>> -template <typename NodeTy> class ilist_half_node;
>>>>>> -template <typename NodeTy> class ilist_node;
>>>>>> +/// Type trait to check for a traits class that has a createSentinel member (as
>>>>>> +/// a canary for any of the ilist_sentinel_traits API).
>>>>>> +template <class TraitsT> struct HasCreateSentinel {
>>>>>> + typedef char Yes[1];
>>>>>> + typedef char No[2];
>>>>>> + template <size_t N> struct SFINAE {};
>>>>>>
>>>>>> -/// Traits with an embedded ilist_node as a sentinel.
>>>>>> -template <typename NodeTy> struct ilist_embedded_sentinel_traits {
>>>>>> - /// Get hold of the node that marks the end of the list.
>>>>>> - ///
>>>>>> - /// FIXME: This downcast is UB. See llvm.org/PR26753.
>>>>>> - LLVM_NO_SANITIZE("object-size")
>>>>>> - NodeTy *createSentinel() const {
>>>>>> - // Since i(p)lists always publicly derive from their corresponding traits,
>>>>>> - // placing a data member in this class will augment the i(p)list. But since
>>>>>> - // the NodeTy is expected to be publicly derive from ilist_node<NodeTy>,
>>>>>> - // there is a legal viable downcast from it to NodeTy. We use this trick to
>>>>>> - // superimpose an i(p)list with a "ghostly" NodeTy, which becomes the
>>>>>> - // sentinel. Dereferencing the sentinel is forbidden (save the
>>>>>> - // ilist_node<NodeTy>), so no one will ever notice the superposition.
>>>>>> - return static_cast<NodeTy *>(&Sentinel);
>>>>>> - }
>>>>>> - static void destroySentinel(NodeTy *) {}
>>>>>> -
>>>>>> - NodeTy *provideInitialHead() const { return createSentinel(); }
>>>>>> - NodeTy *ensureHead(NodeTy *) const { return createSentinel(); }
>>>>>> - static void noteHead(NodeTy *, NodeTy *) {}
>>>>>> + template <class U>
>>>>>> + static Yes &
>>>>>> + hasCreateSentinel(SFINAE<sizeof(make<U>().createSentinel())> * = 0);
>>>>>> + template <class U> static No &hasCreateSentinel(...);
>>>>>>
>>>>>> -private:
>>>>>> - mutable ilist_node<NodeTy> Sentinel;
>>>>>> + static const bool value =
>>>>>> + sizeof(hasCreateSentinel<TraitsT>(nullptr)) == sizeof(Yes);
>>>>>> };
>>>>>>
>>>>>> -/// Trait with an embedded ilist_half_node as a sentinel.
>>>>>> -template <typename NodeTy> struct ilist_half_embedded_sentinel_traits {
>>>>>> - /// Get hold of the node that marks the end of the list.
>>>>>> - ///
>>>>>> - /// FIXME: This downcast is UB. See llvm.org/PR26753.
>>>>>> - LLVM_NO_SANITIZE("object-size")
>>>>>> - NodeTy *createSentinel() const {
>>>>>> - // See comment in ilist_embedded_sentinel_traits::createSentinel().
>>>>>> - return static_cast<NodeTy *>(&Sentinel);
>>>>>> - }
>>>>>> - static void destroySentinel(NodeTy *) {}
>>>>>> -
>>>>>> - NodeTy *provideInitialHead() const { return createSentinel(); }
>>>>>> - NodeTy *ensureHead(NodeTy *) const { return createSentinel(); }
>>>>>> - static void noteHead(NodeTy *, NodeTy *) {}
>>>>>> -
>>>>>> -private:
>>>>>> - mutable ilist_half_node<NodeTy> Sentinel;
>>>>>> -};
>>>>>> +} // end namespace ilist_detail
>>>>>>
>>>>>> -/// Traits with an embedded full node as a sentinel.
>>>>>> -template <typename NodeTy> struct ilist_full_embedded_sentinel_traits {
>>>>>> - /// Get hold of the node that marks the end of the list.
>>>>>> - NodeTy *createSentinel() const { return &Sentinel; }
>>>>>> - static void destroySentinel(NodeTy *) {}
>>>>>> -
>>>>>> - NodeTy *provideInitialHead() const { return createSentinel(); }
>>>>>> - NodeTy *ensureHead(NodeTy *) const { return createSentinel(); }
>>>>>> - static void noteHead(NodeTy *, NodeTy *) {}
>>>>>> +template <typename NodeTy> struct ilist_traits;
>>>>>>
>>>>>> -private:
>>>>>> - mutable NodeTy Sentinel;
>>>>>> -};
>>>>>> +// TODO: Delete uses from subprojects, then delete these.
>>>>>> +template <typename NodeTy> struct ilist_sentinel_traits {};
>>>>>> +template <typename NodeTy> struct ilist_embedded_sentinel_traits {};
>>>>>> +template <typename NodeTy> struct ilist_half_embedded_sentinel_traits {};
>>>>>> +template <typename NodeTy> struct ilist_full_embedded_sentinel_traits {};
>>>>>>
>>>>>> /// ilist_node_traits - A fragment for template traits for intrusive list
>>>>>> /// that provides default node related operations.
>>>>>> @@ -219,8 +143,7 @@ struct ilist_node_traits {
>>>>>> /// for all common operations.
>>>>>> ///
>>>>>> template <typename NodeTy>
>>>>>> -struct ilist_default_traits : public ilist_sentinel_traits<NodeTy>,
>>>>>> - public ilist_node_traits<NodeTy> {};
>>>>>> +struct ilist_default_traits : public ilist_node_traits<NodeTy> {};
>>>>>>
>>>>>> // Template traits for intrusive list. By specializing this template class, you
>>>>>> // can change what next/prev fields are used to store the links...
>>>>>> @@ -263,16 +186,15 @@ public:
>>>>>> typedef node_type &node_reference;
>>>>>>
>>>>>> private:
>>>>>> - pointer NodePtr;
>>>>>> + node_pointer NodePtr = nullptr;
>>>>>>
>>>>>> public:
>>>>>> /// Create from an ilist_node.
>>>>>> - explicit ilist_iterator(node_reference N)
>>>>>> - : NodePtr(static_cast<NodeTy *>(&N)) {}
>>>>>> + explicit ilist_iterator(node_reference N) : NodePtr(&N) {}
>>>>>>
>>>>>> explicit ilist_iterator(pointer NP) : NodePtr(NP) {}
>>>>>> explicit ilist_iterator(reference NR) : NodePtr(&NR) {}
>>>>>> - ilist_iterator() : NodePtr(nullptr) {}
>>>>>> + ilist_iterator() = default;
>>>>>>
>>>>>> // This is templated so that we can allow constructing a const iterator from
>>>>>> // a nonconst iterator...
>>>>>> @@ -281,20 +203,23 @@ public:
>>>>>> const ilist_iterator<node_ty> &RHS,
>>>>>> typename std::enable_if<std::is_convertible<node_ty *, NodeTy *>::value,
>>>>>> void *>::type = nullptr)
>>>>>> - : NodePtr(RHS.getNodePtrUnchecked()) {}
>>>>>> + : NodePtr(RHS.getNodePtr()) {}
>>>>>>
>>>>>> // This is templated so that we can allow assigning to a const iterator from
>>>>>> // a nonconst iterator...
>>>>>> template <class node_ty>
>>>>>> const ilist_iterator &operator=(const ilist_iterator<node_ty> &RHS) {
>>>>>> - NodePtr = RHS.getNodePtrUnchecked();
>>>>>> + NodePtr = RHS.getNodePtr();
>>>>>> return *this;
>>>>>> }
>>>>>>
>>>>>> void reset(pointer NP) { NodePtr = NP; }
>>>>>>
>>>>>> // Accessors...
>>>>>> - reference operator*() const { return *NodePtr; }
>>>>>> + reference operator*() const {
>>>>>> + assert(!NodePtr->isKnownSentinel());
>>>>>> + return static_cast<NodeTy &>(*getNodePtr());
>>>>>> + }
>>>>>> pointer operator->() const { return &operator*(); }
>>>>>>
>>>>>> // Comparison operators
>>>>>> @@ -328,9 +253,6 @@ public:
>>>>>>
>>>>>> /// Get the underlying ilist_node.
>>>>>> node_pointer getNodePtr() const { return static_cast<node_pointer>(NodePtr); }
>>>>>> -
>>>>>> - // Internal interface, do not use...
>>>>>> - pointer getNodePtrUnchecked() const { return NodePtr; }
>>>>>> };
>>>>>>
>>>>>> // Allow ilist_iterators to convert into pointers to a node automatically when
>>>>>> @@ -356,56 +278,33 @@ template<typename NodeTy> struct simplif
>>>>>>
>>>>>> //===----------------------------------------------------------------------===//
>>>>>> //
>>>>>> -/// iplist - The subset of list functionality that can safely be used on nodes
>>>>>> -/// of polymorphic types, i.e. a heterogeneous list with a common base class that
>>>>>> -/// holds the next/prev pointers. The only state of the list itself is a single
>>>>>> -/// pointer to the head of the list.
>>>>>> -///
>>>>>> -/// This list can be in one of three interesting states:
>>>>>> -/// 1. The list may be completely unconstructed. In this case, the head
>>>>>> -/// pointer is null. When in this form, any query for an iterator (e.g.
>>>>>> -/// begin() or end()) causes the list to transparently change to state #2.
>>>>>> -/// 2. The list may be empty, but contain a sentinel for the end iterator. This
>>>>>> -/// sentinel is created by the Traits::createSentinel method and is a link
>>>>>> -/// in the list. When the list is empty, the pointer in the iplist points
>>>>>> -/// to the sentinel. Once the sentinel is constructed, it
>>>>>> -/// is not destroyed until the list is.
>>>>>> -/// 3. The list may contain actual objects in it, which are stored as a doubly
>>>>>> -/// linked list of nodes. One invariant of the list is that the predecessor
>>>>>> -/// of the first node in the list always points to the last node in the list,
>>>>>> -/// and the successor pointer for the sentinel (which always stays at the
>>>>>> -/// end of the list) is always null.
>>>>>> -///
>>>>>> +/// The subset of list functionality that can safely be used on nodes of
>>>>>> +/// polymorphic types, i.e. a heterogeneous list with a common base class that
>>>>>> +/// holds the next/prev pointers. The only state of the list itself is an
>>>>>> +/// ilist_sentinel, which holds pointers to the first and last nodes in the
>>>>>> +/// list.
>>>>>> template <typename NodeTy, typename Traits = ilist_traits<NodeTy>>
>>>>>> class iplist : public Traits, ilist_node_access {
>>>>>> + // TODO: Drop these assertions anytime after 4.0 is branched (keep them for
>>>>>> + // one release to help out-of-tree code update).
>>>>>> #if !defined(_MSC_VER)
>>>>>> // FIXME: This fails in MSVC, but it's worth keeping around to help
>>>>>> // non-Windows users root out bugs in their ilist_traits.
>>>>>> static_assert(!ilist_detail::HasGetNext<Traits, NodeTy>::value,
>>>>>> "ilist next and prev links are not customizable!");
>>>>>> + static_assert(!ilist_detail::HasCreateSentinel<Traits>::value,
>>>>>> + "ilist sentinel is not customizable!");
>>>>>> #endif
>>>>>>
>>>>>> - mutable NodeTy *Head;
>>>>>> + ilist_sentinel<NodeTy> Sentinel;
>>>>>>
>>>>>> - // Use the prev node pointer of 'head' as the tail pointer. This is really a
>>>>>> - // circularly linked list where we snip the 'next' link from the sentinel node
>>>>>> - // back to the first node in the list (to preserve assertions about going off
>>>>>> - // the end of the list).
>>>>>> - NodeTy *getTail() { return this->ensureHead(Head); }
>>>>>> - const NodeTy *getTail() const { return this->ensureHead(Head); }
>>>>>> - void setTail(NodeTy *N) const { this->noteHead(Head, N); }
>>>>>> -
>>>>>> - /// CreateLazySentinel - This method verifies whether the sentinel for the
>>>>>> - /// list has been created and lazily makes it if not.
>>>>>> - void CreateLazySentinel() const {
>>>>>> - this->ensureHead(Head);
>>>>>> - }
>>>>>> + typedef ilist_node<NodeTy> node_type;
>>>>>> + typedef const ilist_node<NodeTy> const_node_type;
>>>>>>
>>>>>> static bool op_less(NodeTy &L, NodeTy &R) { return L < R; }
>>>>>> static bool op_equal(NodeTy &L, NodeTy &R) { return L == R; }
>>>>>>
>>>>>> - // No fundamental reason why iplist can't be copyable, but the default
>>>>>> - // copy/copy-assign won't do.
>>>>>> + // Copying intrusively linked nodes doesn't make sense.
>>>>>> iplist(const iplist &) = delete;
>>>>>> void operator=(const iplist &) = delete;
>>>>>>
>>>>>> @@ -422,30 +321,14 @@ public:
>>>>>> typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
>>>>>> typedef std::reverse_iterator<iterator> reverse_iterator;
>>>>>>
>>>>>> - iplist() : Head(this->provideInitialHead()) {}
>>>>>> - ~iplist() {
>>>>>> - if (!Head) return;
>>>>>> - clear();
>>>>>> - Traits::destroySentinel(getTail());
>>>>>> - }
>>>>>> + iplist() = default;
>>>>>> + ~iplist() { clear(); }
>>>>>>
>>>>>> // Iterator creation methods.
>>>>>> - iterator begin() {
>>>>>> - CreateLazySentinel();
>>>>>> - return iterator(Head);
>>>>>> - }
>>>>>> - const_iterator begin() const {
>>>>>> - CreateLazySentinel();
>>>>>> - return const_iterator(Head);
>>>>>> - }
>>>>>> - iterator end() {
>>>>>> - CreateLazySentinel();
>>>>>> - return iterator(getTail());
>>>>>> - }
>>>>>> - const_iterator end() const {
>>>>>> - CreateLazySentinel();
>>>>>> - return const_iterator(getTail());
>>>>>> - }
>>>>>> + iterator begin() { return ++iterator(Sentinel); }
>>>>>> + const_iterator begin() const { return ++const_iterator(Sentinel); }
>>>>>> + iterator end() { return iterator(Sentinel); }
>>>>>> + const_iterator end() const { return const_iterator(Sentinel); }
>>>>>>
>>>>>> // reverse iterator creation methods.
>>>>>> reverse_iterator rbegin() { return reverse_iterator(end()); }
>>>>>> @@ -456,44 +339,39 @@ public:
>>>>>>
>>>>>> // Miscellaneous inspection routines.
>>>>>> size_type max_size() const { return size_type(-1); }
>>>>>> - bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const {
>>>>>> - return !Head || Head == getTail();
>>>>>> - }
>>>>>> + bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const { return Sentinel.empty(); }
>>>>>>
>>>>>> // Front and back accessor functions...
>>>>>> reference front() {
>>>>>> assert(!empty() && "Called front() on empty list!");
>>>>>> - return *Head;
>>>>>> + return *begin();
>>>>>> }
>>>>>> const_reference front() const {
>>>>>> assert(!empty() && "Called front() on empty list!");
>>>>>> - return *Head;
>>>>>> + return *begin();
>>>>>> }
>>>>>> reference back() {
>>>>>> assert(!empty() && "Called back() on empty list!");
>>>>>> - return *this->getPrev(getTail());
>>>>>> + return *--end();
>>>>>> }
>>>>>> const_reference back() const {
>>>>>> assert(!empty() && "Called back() on empty list!");
>>>>>> - return *this->getPrev(getTail());
>>>>>> + return *--end();
>>>>>> }
>>>>>>
>>>>>> void swap(iplist &RHS) {
>>>>>> assert(0 && "Swap does not use list traits callback correctly yet!");
>>>>>> - std::swap(Head, RHS.Head);
>>>>>> + std::swap(Sentinel, RHS.Sentinel);
>>>>>> }
>>>>>>
>>>>>> iterator insert(iterator where, NodeTy *New) {
>>>>>> - NodeTy *CurNode = where.getNodePtrUnchecked();
>>>>>> - NodeTy *PrevNode = this->getPrev(CurNode);
>>>>>> - this->setNext(New, CurNode);
>>>>>> - this->setPrev(New, PrevNode);
>>>>>> -
>>>>>> - if (CurNode != Head) // Is PrevNode off the beginning of the list?
>>>>>> - this->setNext(PrevNode, New);
>>>>>> - else
>>>>>> - Head = New;
>>>>>> - this->setPrev(CurNode, New);
>>>>>> + node_type *NewN = this->getNodePtr(New);
>>>>>> + node_type *Next = where.getNodePtr();
>>>>>> + node_type *Prev = this->getPrev(Next);
>>>>>> + this->setNext(NewN, Next);
>>>>>> + this->setPrev(NewN, Prev);
>>>>>> + this->setNext(Prev, NewN);
>>>>>> + this->setPrev(Next, NewN);
>>>>>>
>>>>>> this->addNodeToList(New); // Notify traits that we added a node...
>>>>>> return iterator(New);
>>>>>> @@ -513,24 +391,23 @@ public:
>>>>>> NodeTy *remove(iterator &IT) {
>>>>>> assert(IT != end() && "Cannot remove end of list!");
>>>>>> NodeTy *Node = &*IT;
>>>>>> - NodeTy *NextNode = this->getNext(Node);
>>>>>> - NodeTy *PrevNode = this->getPrev(Node);
>>>>>> -
>>>>>> - if (Node != Head) // Is PrevNode off the beginning of the list?
>>>>>> - this->setNext(PrevNode, NextNode);
>>>>>> - else
>>>>>> - Head = NextNode;
>>>>>> - this->setPrev(NextNode, PrevNode);
>>>>>> - IT.reset(NextNode);
>>>>>> + node_type *Base = this->getNodePtr(Node);
>>>>>> + node_type *Next = this->getNext(Base);
>>>>>> + node_type *Prev = this->getPrev(Base);
>>>>>> +
>>>>>> + this->setNext(Prev, Next);
>>>>>> + this->setPrev(Next, Prev);
>>>>>> + IT = iterator(*Next);
>>>>>> this->removeNodeFromList(Node); // Notify traits that we removed a node...
>>>>>>
>>>>>> // Set the next/prev pointers of the current node to null. This isn't
>>>>>> // strictly required, but this catches errors where a node is removed from
>>>>>> // an ilist (and potentially deleted) with iterators still pointing at it.
>>>>>> - // When those iterators are incremented or decremented, they will assert on
>>>>>> - // the null next/prev pointer instead of "usually working".
>>>>>> - this->setNext(Node, nullptr);
>>>>>> - this->setPrev(Node, nullptr);
>>>>>> + // After those iterators are incremented or decremented, they become
>>>>>> + // default-constructed iterators, and will assert on increment, decrement,
>>>>>> + // and dereference instead of "usually working".
>>>>>> + this->setNext(Base, nullptr);
>>>>>> + this->setPrev(Base, nullptr);
>>>>>> return Node;
>>>>>> }
>>>>>>
>>>>>> @@ -556,12 +433,7 @@ public:
>>>>>> ///
>>>>>> /// This should only be used immediately before freeing nodes in bulk to
>>>>>> /// avoid traversing the list and bringing all the nodes into cache.
>>>>>> - void clearAndLeakNodesUnsafely() {
>>>>>> - if (Head) {
>>>>>> - Head = getTail();
>>>>>> - this->setPrev(Head, Head);
>>>>>> - }
>>>>>> - }
>>>>>> + void clearAndLeakNodesUnsafely() { Sentinel.reset(); }
>>>>>>
>>>>>> private:
>>>>>> // transfer - The heart of the splice function. Move linked list nodes from
>>>>>> @@ -570,48 +442,34 @@ private:
>>>>>> void transfer(iterator position, iplist &L2, iterator first, iterator last) {
>>>>>> assert(first != last && "Should be checked by callers");
>>>>>> // Position cannot be contained in the range to be transferred.
>>>>>> - // Check for the most common mistake.
>>>>>> assert(position != first &&
>>>>>> + // Check for the most common mistake.
>>>>>> "Insertion point can't be one of the transferred nodes");
>>>>>>
>>>>>> - if (position != last) {
>>>>>> - // Note: we have to be careful about the case when we move the first node
>>>>>> - // in the list. This node is the list sentinel node and we can't move it.
>>>>>> - NodeTy *ThisSentinel = getTail();
>>>>>> - setTail(nullptr);
>>>>>> - NodeTy *L2Sentinel = L2.getTail();
>>>>>> - L2.setTail(nullptr);
>>>>>> -
>>>>>> - // Remove [first, last) from its old position.
>>>>>> - NodeTy *First = &*first, *Prev = this->getPrev(First);
>>>>>> - NodeTy *Next = last.getNodePtrUnchecked(), *Last = this->getPrev(Next);
>>>>>> - if (Prev)
>>>>>> - this->setNext(Prev, Next);
>>>>>> - else
>>>>>> - L2.Head = Next;
>>>>>> - this->setPrev(Next, Prev);
>>>>>> -
>>>>>> - // Splice [first, last) into its new position.
>>>>>> - NodeTy *PosNext = position.getNodePtrUnchecked();
>>>>>> - NodeTy *PosPrev = this->getPrev(PosNext);
>>>>>> -
>>>>>> - // Fix head of list...
>>>>>> - if (PosPrev)
>>>>>> - this->setNext(PosPrev, First);
>>>>>> - else
>>>>>> - Head = First;
>>>>>> - this->setPrev(First, PosPrev);
>>>>>> -
>>>>>> - // Fix end of list...
>>>>>> - this->setNext(Last, PosNext);
>>>>>> - this->setPrev(PosNext, Last);
>>>>>> -
>>>>>> - this->transferNodesFromList(L2, iterator(First), iterator(PosNext));
>>>>>> -
>>>>>> - // Now that everything is set, restore the pointers to the list sentinels.
>>>>>> - L2.setTail(L2Sentinel);
>>>>>> - setTail(ThisSentinel);
>>>>>> - }
>>>>>> + if (position == last)
>>>>>> + return;
>>>>>> +
>>>>>> + // Get raw hooks to the first and final nodes being transferred.
>>>>>> + node_type *First = first.getNodePtr();
>>>>>> + node_type *Final = (--last).getNodePtr();
>>>>>> +
>>>>>> + // Detach from old list/position.
>>>>>> + node_type *Prev = this->getPrev(First);
>>>>>> + node_type *Next = this->getNext(Final);
>>>>>> + this->setNext(Prev, Next);
>>>>>> + this->setPrev(Next, Prev);
>>>>>> +
>>>>>> + // Splice [First, Final] into its new list/position.
>>>>>> + Next = position.getNodePtr();
>>>>>> + Prev = this->getPrev(Next);
>>>>>> + this->setNext(Final, Next);
>>>>>> + this->setPrev(First, Prev);
>>>>>> + this->setNext(Prev, First);
>>>>>> + this->setPrev(Next, Final);
>>>>>> +
>>>>>> + // Callback. Note that the nodes have moved from before-last to
>>>>>> + // before-position.
>>>>>> + this->transferNodesFromList(L2, first, position);
>>>>>> }
>>>>>>
>>>>>> public:
>>>>>> @@ -621,7 +479,6 @@ public:
>>>>>> //
>>>>>>
>>>>>> size_type LLVM_ATTRIBUTE_UNUSED_RESULT size() const {
>>>>>> - if (!Head) return 0; // Don't require construction of sentinel if empty.
>>>>>> return std::distance(begin(), end());
>>>>>> }
>>>>>>
>>>>>> @@ -631,7 +488,7 @@ public:
>>>>>> return last;
>>>>>> }
>>>>>>
>>>>>> - void clear() { if (Head) erase(begin(), end()); }
>>>>>> + void clear() { erase(begin(), end()); }
>>>>>>
>>>>>> // Front and back inserters...
>>>>>> void push_front(NodeTy *val) { insert(begin(), val); }
>>>>>>
>>>>>> Modified: llvm/trunk/include/llvm/ADT/ilist_node.h
>>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/ilist_node.h?rev=278974&r1=278973&r2=278974&view=diff
>>>>>> ==============================================================================
>>>>>> --- llvm/trunk/include/llvm/ADT/ilist_node.h (original)
>>>>>> +++ llvm/trunk/include/llvm/ADT/ilist_node.h Wed Aug 17 15:44:33 2016
>>>>>> @@ -15,6 +15,8 @@
>>>>>> #ifndef LLVM_ADT_ILIST_NODE_H
>>>>>> #define LLVM_ADT_ILIST_NODE_H
>>>>>>
>>>>>> +#include <llvm/ADT/PointerIntPair.h>
>>>>>> +
>>>>>> namespace llvm {
>>>>>>
>>>>>> template<typename NodeTy>
>>>>>> @@ -22,46 +24,81 @@ struct ilist_traits;
>>>>>> template <typename NodeTy> struct ilist_embedded_sentinel_traits;
>>>>>> template <typename NodeTy> struct ilist_half_embedded_sentinel_traits;
>>>>>>
>>>>>> -/// ilist_half_node - Base class that provides prev services for sentinels.
>>>>>> -///
>>>>>> -template<typename NodeTy>
>>>>>> -class ilist_half_node {
>>>>>> - friend struct ilist_traits<NodeTy>;
>>>>>> - friend struct ilist_half_embedded_sentinel_traits<NodeTy>;
>>>>>> - NodeTy *Prev;
>>>>>> -protected:
>>>>>> - NodeTy *getPrev() { return Prev; }
>>>>>> - const NodeTy *getPrev() const { return Prev; }
>>>>>> - void setPrev(NodeTy *P) { Prev = P; }
>>>>>> - ilist_half_node() : Prev(nullptr) {}
>>>>>> +/// Base class for ilist nodes.
>>>>>> +struct ilist_node_base {
>>>>>> +#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
>>>>>> + PointerIntPair<ilist_node_base *, 1> PrevAndSentinel;
>>>>>> +
>>>>>> + void setPrev(ilist_node_base *Prev) { PrevAndSentinel.setPointer(Prev); }
>>>>>> + ilist_node_base *getPrev() const { return PrevAndSentinel.getPointer(); }
>>>>>> +
>>>>>> + bool isKnownSentinel() const { return PrevAndSentinel.getInt(); }
>>>>>> + void initializeSentinel() { PrevAndSentinel.setInt(true); }
>>>>>> +#else
>>>>>> + ilist_node_base *Prev = nullptr;
>>>>>> +
>>>>>> + void setPrev(ilist_node_base *Prev) { this->Prev = Prev; }
>>>>>> + ilist_node_base *getPrev() const { return Prev; }
>>>>>> +
>>>>>> + bool isKnownSentinel() const { return false; }
>>>>>> + void initializeSentinel() {}
>>>>>> +#endif
>>>>>> +
>>>>>> + ilist_node_base *Next = nullptr;
>>>>>> };
>>>>>>
>>>>>> struct ilist_node_access;
>>>>>> template <typename NodeTy> class ilist_iterator;
>>>>>> +template <typename NodeTy> class ilist_sentinel;
>>>>>>
>>>>>> -/// Base class that provides next/prev services for ilist nodes.
>>>>>> -template<typename NodeTy>
>>>>>> -class ilist_node : private ilist_half_node<NodeTy> {
>>>>>> +/// Templated wrapper class.
>>>>>> +template <typename NodeTy> class ilist_node : ilist_node_base {
>>>>>> friend struct ilist_node_access;
>>>>>> friend struct ilist_traits<NodeTy>;
>>>>>> friend struct ilist_half_embedded_sentinel_traits<NodeTy>;
>>>>>> friend struct ilist_embedded_sentinel_traits<NodeTy>;
>>>>>> - NodeTy *Next;
>>>>>> - NodeTy *getNext() { return Next; }
>>>>>> - const NodeTy *getNext() const { return Next; }
>>>>>> - void setNext(NodeTy *N) { Next = N; }
>>>>>> + friend class ilist_iterator<NodeTy>;
>>>>>> + friend class ilist_sentinel<NodeTy>;
>>>>>> +
>>>>>> protected:
>>>>>> - ilist_node() : Next(nullptr) {}
>>>>>> + ilist_node() = default;
>>>>>>
>>>>>> -public:
>>>>>> - ilist_iterator<NodeTy> getIterator() {
>>>>>> - // FIXME: Stop downcasting to create the iterator (potential UB).
>>>>>> - return ilist_iterator<NodeTy>(static_cast<NodeTy *>(this));
>>>>>> +private:
>>>>>> + ilist_node *getPrev() {
>>>>>> + return static_cast<ilist_node *>(ilist_node_base::getPrev());
>>>>>> + }
>>>>>> + ilist_node *getNext() { return static_cast<ilist_node *>(Next); }
>>>>>> +
>>>>>> + const ilist_node *getPrev() const {
>>>>>> + return static_cast<ilist_node *>(ilist_node_base::getPrev());
>>>>>> }
>>>>>> + const ilist_node *getNext() const { return static_cast<ilist_node *>(Next); }
>>>>>> +
>>>>>> + void setPrev(ilist_node *N) { ilist_node_base::setPrev(N); }
>>>>>> + void setNext(ilist_node *N) { Next = N; }
>>>>>> +
>>>>>> +public:
>>>>>> + ilist_iterator<NodeTy> getIterator() { return ilist_iterator<NodeTy>(*this); }
>>>>>> ilist_iterator<const NodeTy> getIterator() const {
>>>>>> - // FIXME: Stop downcasting to create the iterator (potential UB).
>>>>>> - return ilist_iterator<const NodeTy>(static_cast<const NodeTy *>(this));
>>>>>> + return ilist_iterator<const NodeTy>(*this);
>>>>>> }
>>>>>> +
>>>>>> + using ilist_node_base::isKnownSentinel;
>>>>>> +};
>>>>>> +
>>>>>> +template <typename NodeTy> class ilist_sentinel : public ilist_node<NodeTy> {
>>>>>> +public:
>>>>>> + ilist_sentinel() {
>>>>>> + ilist_node_base::initializeSentinel();
>>>>>> + reset();
>>>>>> + }
>>>>>> +
>>>>>> + void reset() {
>>>>>> + this->setPrev(this);
>>>>>> + this->setNext(this);
>>>>>> + }
>>>>>> +
>>>>>> + bool empty() const { return this == this->getPrev(); }
>>>>>> };
>>>>>>
>>>>>> /// An ilist node that can access its parent list.
>>>>>>
>>>>>> Modified: llvm/trunk/unittests/ADT/ilistTest.cpp
>>>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/ilistTest.cpp?rev=278974&r1=278973&r2=278974&view=diff
>>>>>> ==============================================================================
>>>>>> --- llvm/trunk/unittests/ADT/ilistTest.cpp (original)
>>>>>> +++ llvm/trunk/unittests/ADT/ilistTest.cpp Wed Aug 17 15:44:33 2016
>>>>>> @@ -128,4 +128,66 @@ TEST(ilistTest, UnsafeClear) {
>>>>>> EXPECT_EQ(6, List.back().Value);
>>>>>> }
>>>>>>
>>>>>> +struct NodeWithCallback : ilist_node<NodeWithCallback> {
>>>>>> + int Value = 0;
>>>>>> + bool IsInList = false;
>>>>>> +
>>>>>> + NodeWithCallback() = default;
>>>>>> + NodeWithCallback(int Value) : Value(Value) {}
>>>>>> + NodeWithCallback(const NodeWithCallback &) = delete;
>>>>>> +};
>>>>>> +
>>>>>> +} // end namespace
>>>>>> +
>>>>>> +namespace llvm {
>>>>>> +template <>
>>>>>> +struct ilist_traits<NodeWithCallback>
>>>>>> + : public ilist_node_traits<NodeWithCallback> {
>>>>>> + void addNodeToList(NodeWithCallback *N) { N->IsInList = true; }
>>>>>> + void removeNodeFromList(NodeWithCallback *N) { N->IsInList = false; }
>>>>>> +};
>>>>>> +} // end namespace llvm
>>>>>> +
>>>>>> +namespace {
>>>>>> +
>>>>>> +TEST(ilistTest, addNodeToList) {
>>>>>> + ilist<NodeWithCallback> L;
>>>>>> + NodeWithCallback N(7);
>>>>>> + ASSERT_FALSE(N.IsInList);
>>>>>> +
>>>>>> + L.insert(L.begin(), &N);
>>>>>> + ASSERT_EQ(1u, L.size());
>>>>>> + ASSERT_EQ(&N, &*L.begin());
>>>>>> + ASSERT_TRUE(N.IsInList);
>>>>>> +
>>>>>> + L.remove(&N);
>>>>>> + ASSERT_EQ(0u, L.size());
>>>>>> + ASSERT_FALSE(N.IsInList);
>>>>>> }
>>>>>> +
>>>>>> +struct PrivateNode : private ilist_node<PrivateNode> {
>>>>>> + friend struct llvm::ilist_node_access;
>>>>>> +
>>>>>> + int Value = 0;
>>>>>> +
>>>>>> + PrivateNode() = default;
>>>>>> + PrivateNode(int Value) : Value(Value) {}
>>>>>> + PrivateNode(const PrivateNode &) = delete;
>>>>>> +};
>>>>>> +
>>>>>> +TEST(ilistTest, privateNode) {
>>>>>> + // Instantiate various APIs to be sure they're callable when ilist_node is
>>>>>> + // inherited privately.
>>>>>> + ilist<NodeWithCallback> L;
>>>>>> + NodeWithCallback N(7);
>>>>>> + L.insert(L.begin(), &N);
>>>>>> + ++L.begin();
>>>>>> + (void)*L.begin();
>>>>>> + (void)(L.begin() == L.end());
>>>>>> +
>>>>>> + ilist<NodeWithCallback> L2;
>>>>>> + L2.splice(L2.end(), L);
>>>>>> + L2.remove(&N);
>>>>>> +}
>>>>>> +
>>>>>> +} // end namespace
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> llvm-commits mailing list
>>>>>> llvm-commits at lists.llvm.org
>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>>> _______________________________________________
>>>> llvm-commits mailing list
>>>> llvm-commits at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>>
>>> _______________________________________________
>>> llvm-commits mailing list
>>> llvm-commits at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>
More information about the llvm-commits
mailing list