When porting large bodies of code from using const char*
to StringRef, it is helpful to be able to treat nullptr
as an empty string, since that it is often what it is used
to indicate in C-style code.
Differential Revision: https://reviews.llvm.org/D24697
llvm-svn: 281906
Remove createNode() and any API that depending on it, and add
HasCreateNode to the list of checks for HasObsoleteCustomizations. Now
an ilist *never* allocates (this was already true for iplist).
This factors out all the differences between iplist and ilist. I'll aim
to rename both to "owning_ilist" eventually, to call out the interesting
(not exactly intrusive) ownership semantics. In the meantime, I've left
both names around to reduce code churn.
One of the deleted APIs is the ilist copy constructor. I've lifted up
and tested iplist::cloneFrom (ala simple_ilist::cloneFrom) as a
replacement.
Users of ilist<> and iplist<> that want the list to allocate nodes have
a few options:
- use std::list;
- use AllocatorList or BumpPtrList (or build a similarly trivial list);
- use cloneFrom (which is explicit at the call site); or
- allocate at the call site.
See r280573, r281177, r281181, and r281182 for examples of what to do if
you're updating out-of-tree code.
llvm-svn: 281184
- Add AllocatorList, a non-intrusive list that owns an LLVM-style
allocator and provides a std::list-like interface (trivially built on
top of simple_ilist),
- add a typedef (and unit tests) for BumpPtrList, and
- use BumpPtrList for the list of llvm::yaml::Token (i.e., TokenQueueT).
TokenQueueT has no need for the complexity of an intrusive list. The
only reason to inherit from ilist was to customize the allocator.
TokenQueueT was the only example in-tree of using ilist<> in a truly
non-intrusive way.
Moreover, this removes the final use of the non-intrusive
ilist_traits<>::createNode (after r280573, r281177, and r281181). I
have a WIP patch that removes this customization point (and the API that
relies on it) that I plan to commit soon.
Note: AllocatorList owns the allocator, which limits the viable API
(e.g., splicing must be on the same list). For now I've left out
any problematic API. It wouldn't be hard to split AllocatorList into
two layers: an Impl class that calls DerivedT::getAlloc (via CRTP), and
derived classes that handle Allocator ownership/reference/etc semantics;
and then implement splice with appropriate assertions; but TBH we should
probably just customize the std::list allocators at that point.
llvm-svn: 281182
Force IVUsers to be moved instead of copied, properly update Parent
pointers in IVStrideUse when IVUsers is moved, and make sure we have
move constructors available in iplist and ilist.
I came across this in a WIP patch that deleted the copy constructors
from ilist. I was surprised to find that IVUsersAnalysis couldn't be
registered in the new pass manager.
It's not clear to me whether IVUsers was getting moved only when empty,
but if it was being moved when it was non-empty then this fixes a
pointer invalidation bug and should give some sort of speedup. Note
that the bugfix would be necessary even for a copy constructor.
llvm-svn: 281181
ilist_iterator::reset was unnecessary API, and wasn't any clearer (or
safer) at the call site than constructing a temporary and assigning it
to the iterator.
llvm-svn: 281175
Add an assertion to the MachineInstrBundleIterator from instr_iterator
that the underlying iterator is valid. This is possible know that we
can check ilist_node::isSentinel (since r281168), and is consistent with
the constructors from MachineInstr* and MachineInstr&.
Avoiding the new assertion in operator== and operator!= requires four
(!!!!) new overloads each.
(As an aside, I'm strongly in favour of:
- making the conversion from instr_iterator explicit;
- making the conversion from pointer explicit;
- making the conversion from reference explicit; and
- removing all the extra overloads of operator== and operator!= except
const_instr_iterator.
I'm not signing up for that at this point, but being clear about when
something is an MachineInstr-iterator (possibly instr_end()) vs
MachineInstr-bundle-iterator (possibly end()) vs MachineInstr* (possibly
nullptr) vs MachineInstr& (known valid) would surely make code
cleaner... and it would remove a ton of boilerplate from
MachineInstrBundleIterator operators.)
llvm-svn: 281170
This adds two declarative configuration options for intrusive lists
(available for simple_ilist, iplist, and ilist). Both of these options
affect ilist_node interoperability and need to be passed both to the
node and the list. Instead of adding a new traits class, they're
specified as optional template parameters (in any order).
The two options:
1. Pass ilist_sentinel_tracking<true> or ilist_sentinel_tracking<false>
to control whether there's a bit on ilist_node "prev" pointer
indicating whether it's the sentinel. The default behaviour is to
use a bit if and only if LLVM_ENABLE_ABI_BREAKING_CHECKS.
2. Pass ilist_tag<TagA> and ilist_tag<TagB> to allow insertion of a
single node into two different lists (simultaneously).
I have an immediate use-case for (1) ilist_sentinel_tracking: fixing the
validation semantics of MachineBasicBlock::reverse_iterator to match
ilist::reverse_iterator (ala r280032: see the comments at the end of the
commit message there). I'm adding (2) ilist_tag in the same commit to
validate that the options framework supports expansion. Justin Bogner
mentioned this might enable a possible cleanup in SelectionDAG, but I'll
leave this to others to explore. In the meantime, the unit tests and
the comments for simple_ilist and ilist_node have usage examples.
Note that there's a layer of indirection to support optional,
out-of-order, template paramaters. Internal classes are templated on an
instantiation of the non-variadic ilist_detail::node_options.
User-facing classes use ilist_detail::compute_node_options to compute
the correct instantiation of ilist_detail::node_options.
The comments for ilist_detail::is_valid_option describe how to add new
options (e.g., ilist_packed_int<int NumBits>).
llvm-svn: 281167
... and make a few ilist-internal API changes, in preparation for
changing how ilist_node is templated. The only effect for ilist users
should be changing the friend target from llvm::ilist_node_access to
llvm::ilist_detail::NodeAccess (which is only necessary when they
inherit privately from ilist_node).
- Split out SpecificNodeAccess, which has overloads of getNodePtr and
getValuePtr that are untemplated.
- Use more typedefs to prevent more changes later.
- Force inheritance to use *NodeAccess (to emphasize that ilist *users*
shouldn't be doing this).
There should be no functionality change here.
llvm-svn: 281142
The latest MSVC update apparently resolve the call from the
const ref variant to itself, leading to an infinite
recursion. It is not clear to me why the r-value overload is
not selected. `ValueT` is a pointer type, and the functional-style
cast in the call `insert_as(ValueT(V), LookupKey);` should result
in a r-value ref. A bug in MSVC?
Differential Revision: https://reviews.llvm.org/D23956
llvm-svn: 280685
The only intrusive thing about SparseBitVector's usage of ilist<> was
that new was usually called externally. There were no custom traits.
It seems like the reason to switch to ilist in r41855 was to avoid
pointer invalidation, but std::list<> has that feature too. Maybe
std::list<>::emplace makes this a little more obvious than it was then.
Switch over to std::list<> and simplify the code.
llvm-svn: 280573
Inheriting from std::iterator uses more boiler-plate than manual
typedefs. Avoid that in both ilist_iterator and
MachineInstrBundleIterator.
This has the side effect of removing ilist_iterator from certain ADL
lookups in namespace std; calls to std::next need to be qualified by
"std::" that didn't have to before. The one case of this in-tree was
operating on a temporary, so I used the more compact operator++.
llvm-svn: 280570
Split out iplist_impl from iplist, and change SymbolTableList to inherit
directly from iplist_impl. This makes it more straightforward to add
new template paramaters to iplist [*]:
- iplist_impl takes a "base" list that provides the intrusive
functionality (usually simple_ilist<T>) and a traits class.
- iplist no longer takes a "Traits" template parameter. It only takes
the value_type, T, and instantiates iplist_impl with simple_ilist<T>
and ilist_traits<T>.
- SymbolTableList now inherits from iplist_impl, instead of iplist.
Note for out-of-tree code: if you have an iplist whose second template
parameter was *not* the default (i.e., not ilist_traits<YourT>), you
have three options:
- Stop using a custom traits class, and instead specialize
ilist_traits<YourT>. This is the usual thing to do.
- Specialize iplist<YourT> to pass your custom traits class into
iplist_impl.
- Create your own trivial list type that passes your custom traits class
into iplist_impl (see SymbolTableList<> for an example).
[*]: The eventual goal is to start tracking a sentinel bit on the
MachineInstr list even when LLVM_ENABLE_ABI_BREAKING_CHECKS is off,
which will enable MachineBasicBlock::reverse_iterator to have normal
list invalidation semantics that matching the new
iplist<>::reverse_iterator from r280032.
llvm-svn: 280569
This test was using the wrong type, and so not actually testing much.
ilist_iterator constructors weren't going through ilist_node_access, so
they didn't actually work with private inheritance.
llvm-svn: 280564
If an attribute name has special characters such as '\01', it is not
properly printed in LLVM assembly language format. Since the format
expects the special characters are printed as it is, it has to contain
escape characters to make it printable.
Before:
attributes #0 = { ... "counting-function"="^A__gnu_mcount_nc" ...
After:
attributes #0 = { ... "counting-function"="\01__gnu_mcount_nc" ...
Reviewers: hfinkel, rengolin, rjmccall, compnerd
Subscribers: nemanjai, mcrosier, hans, shenhan, majnemer, llvm-commits
Differential Revision: https://reviews.llvm.org/D23792
llvm-svn: 280357
Many lists want to override only allocation semantics, or callbacks for
iplist. Split these up to prevent code duplication.
- Specialize ilist_alloc_traits to change the implementations of
deleteNode() and createNode().
- One common desire is to do nothing deleteNode() and disable
createNode(). Specialize ilist_alloc_traits to inherit from
ilist_noalloc_traits for that behaviour.
- Specialize ilist_callback_traits to use the addNodeToList(),
removeNodeFromList(), and transferNodesFromList() callbacks.
As a drive-by, add some coverage to the callback-related unit tests.
llvm-svn: 280128
Guarantee that ilist_traits<T>::transferNodesFromList is only called
when nodes are actually changing lists.
I also moved all the callbacks to occur *first*, before the operation.
This is the only choice for iplist<T>::merge, so we might as well be
consistent. I expect this to have no effect in practice, although it
simplifies the logic in both iplist<T>::transfer and iplist<T>::insert.
llvm-svn: 280122
This is a prep commit before splitting up ilist_node_traits and
updating/simplifying call sites.
- Move to top of file (I considered moving to a different file,
llvm/ADT/ilist_traits.h, but it's really not much code).
- Clang-format.
- Convert comments to doxygen, clean them up, and add TODOs for what I'm
doing next.
llvm-svn: 280109
Split out a new, low-level intrusive list type with clear semantics.
Unlike iplist (and ilist), all operations on simple_ilist are intrusive,
and simple_ilist never takes ownership of its nodes. This enables an
intuitive API that has the right defaults for intrusive lists.
- insert() takes references (not pointers!) to nodes (in iplist/ilist,
passing a reference will cause the node to be copied).
- erase() takes only iterators (like std::list), and does not destroy
the nodes.
- remove() takes only references and has the same behaviour as erase().
- clear() does not destroy the nodes.
- The destructor does not destroy the nodes.
- New API {erase,remove,clear}AndDispose() take an extra Disposer
functor for callsites that want to call some disposal routine (e.g.,
std::default_delete).
This list is not currently configurable, and has no callbacks.
The initial motivation was to fix iplist<>::sort to work correctly (even
with callbacks in ilist_traits<>). iplist<> uses simple_ilist<>::sort
directly. The new test in unittests/IR/ModuleTest.cpp crashes without
this commit.
Fixing sort() via a low-level layer provided a good opportunity to:
- Unit test the low-level functionality thoroughly.
- Modernize the API, largely inspired by other intrusive list
implementations.
Here's a sketch of a longer-term plan:
- Create BumpPtrList<>, a non-intrusive list implemented using
simple_ilist<>, and use it for the Token list in
lib/Support/YAMLParser.cpp. This will factor out the only real use of
createNode().
- Evolve the iplist<> and ilist<> APIs in the direction of
simple_ilist<>, making allocation/deallocation explicit at call sites
(similar to simple_ilist<>::eraseAndDispose()).
- Factor out remaining calls to createNode() and deleteNode() and remove
the customization from ilist_traits<>.
- Transition uses of iplist<>/ilist<> that don't need callbacks over to
simple_ilist<>.
llvm-svn: 280107
I'm working on a lower-level intrusive list that can be used
stand-alone, and splitting the files up a bit will make the code easier
to organize. Explode the ilist headers in advance to improve blame
lists in the future.
- Move ilist_node_base from ilist_node.h to ilist_node_base.h.
- Move ilist_base from ilist.h to ilist_base.h.
- Move ilist_iterator from ilist.h to ilist_iterator.h.
- Move ilist_node_access from ilist.h to ilist_node.h to support
ilist_iterator.
- Update unit tests to #include smaller headers.
- Clang-format the moved things.
I noticed in transit that there is a simplify_type specialization for
ilist_iterator. Since there is no longer an implicit conversion from
ilist<T>::iterator to T*, this doesn't make sense (effectively it's a
form of implicit conversion). For now I've added a FIXME.
llvm-svn: 280047
Reverse iterators to doubly-linked lists can be simpler (and cheaper)
than std::reverse_iterator. Make it so.
In particular, change ilist<T>::reverse_iterator so that it is *never*
invalidated unless the node it references is deleted. This matches the
guarantees of ilist<T>::iterator.
(Note: MachineBasicBlock::iterator is *not* an ilist iterator, but a
MachineInstrBundleIterator<MachineInstr>. This commit does not change
MachineBasicBlock::reverse_iterator, but it does update
MachineBasicBlock::reverse_instr_iterator. See note at end of commit
message for details on bundle iterators.)
Given the list (with the Sentinel showing twice for simplicity):
[Sentinel] <-> A <-> B <-> [Sentinel]
the following is now true:
1. begin() represents A.
2. begin() holds the pointer for A.
3. end() represents [Sentinel].
4. end() holds the poitner for [Sentinel].
5. rbegin() represents B.
6. rbegin() holds the pointer for B.
7. rend() represents [Sentinel].
8. rend() holds the pointer for [Sentinel].
The changes are #6 and #8. Here are some properties from the old
scheme (which used std::reverse_iterator):
- rbegin() held the pointer for [Sentinel] and rend() held the pointer
for A;
- operator*() cost two dereferences instead of one;
- converting from a valid iterator to its valid reverse_iterator
involved a confusing increment; and
- "RI++->erase()" left RI invalid. The unintuitive replacement was
"RI->erase(), RE = end()".
With vector-like data structures these properties are hard to avoid
(since past-the-beginning is not a valid pointer), and don't impose a
real cost (since there's still only one dereference, and all iterators
are invalidated on erase). But with lists, this was a poor design.
Specifically, the following code (which obviously works with normal
iterators) now works with ilist::reverse_iterator as well:
for (auto RI = L.rbegin(), RE = L.rend(); RI != RE;)
fooThatMightRemoveArgFromList(*RI++);
Converting between iterator and reverse_iterator for the same node uses
the getReverse() function.
reverse_iterator iterator::getReverse();
iterator reverse_iterator::getReverse();
Why doesn't iterator <=> reverse_iterator conversion use constructors?
In order to catch and update old code, reverse_iterator does not even
have an explicit conversion from iterator. It wouldn't be safe because
there would be no reasonable way to catch all the bugs from the changed
semantic (see the changes at call sites that are part of this patch).
Old code used this API:
std::reverse_iterator::reverse_iterator(iterator);
iterator std::reverse_iterator::base();
Here's how to update from old code to new (that incorporates the
semantic change), assuming I is an ilist<>::iterator and RI is an
ilist<>::reverse_iterator:
[Old] ==> [New]
reverse_iterator(I) (--I).getReverse()
reverse_iterator(I) ++I.getReverse()
--reverse_iterator(I) I.getReverse()
reverse_iterator(++I) I.getReverse()
RI.base() (--RI).getReverse()
RI.base() ++RI.getReverse()
--RI.base() RI.getReverse()
(++RI).base() RI.getReverse()
delete &*RI, RE = end() delete &*RI++
RI->erase(), RE = end() RI++->erase()
=======================================
Note: bundle iterators are out of scope
=======================================
MachineBasicBlock::iterator, also known as
MachineInstrBundleIterator<MachineInstr>, is a wrapper to represent
MachineInstr bundles. The idea is that each operator++ takes you to the
beginning of the next bundle. Implementing a sane reverse iterator for
this is harder than ilist. Here are the options:
- Use std::reverse_iterator<MBB::i>. Store a handle to the beginning of
the next bundle. A call to operator*() runs a loop (usually
operator--() will be called 1 time, for unbundled instructions).
Increment/decrement just works. This is the status quo.
- Store a handle to the final node in the bundle. A call to operator*()
still runs a loop, but it iterates one time fewer (usually
operator--() will be called 0 times, for unbundled instructions).
Increment/decrement just works.
- Make the ilist_sentinel<MachineInstr> *always* store that it's the
sentinel (instead of just in asserts mode). Then the bundle iterator
can sniff the sentinel bit in operator++().
I initially tried implementing the end() option as part of this commit,
but updating iterator/reverse_iterator conversion call sites was
error-prone. I have a WIP series of patches that implements the final
option.
llvm-svn: 280032
Separate algorithms in iplist<T> that don't depend on T into ilist_base,
and unit test them.
While I was adding unit tests for these algorithms anyway, I also added
unit tests for ilist_node_base and ilist_sentinel<T>.
To make the algorithms and unit tests easier to write, I also did the
following minor changes as a drive-by:
- encapsulate Prev/Next in ilist_node_base to so that algorithms are
easier to read, and
- update ilist_node_access API to take nodes by reference.
There should be no real functionality change here.
llvm-svn: 279484
Summary: Before the change, *Opt never actually gets updated by the end
of toNext(), so for every next time the loop has to start over from
child_begin(). This bug doesn't affect the correctness, since Visited prevents
it from re-entering the same node again; but it's slow.
Reviewers: dberris, dblaikie, dannyb
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D23649
llvm-svn: 279482
Remove all the dead code around ilist_*sentinel_traits. This is a
follow-up to gutting them as part of r279314 (originally r278974),
staged to prevent broken builds in sub-projects.
Uses were removed from clang in r279457 and lld in r279458.
llvm-svn: 279473
Currently nodes_iterator may dereference to a NodeType* or a NodeType&. Make them all dereference to NodeType*, which is NodeRef later.
Differential Revision: https://reviews.llvm.org/D23704
Differential Revision: https://reviews.llvm.org/D23705
llvm-svn: 279326
This reverts commit r279053, reapplying r278974 after fixing PR29035
with r279104.
Note that r279312 has been committed in the meantime, and this has been
rebased on top of that. Otherwise it's identical to r278974.
Note for maintainers of out-of-tree code (that I missed in the original
message): if the new isKnownSentinel() assertion is firing from
ilist_iterator<>::operator*(), this patch has identified a bug in your
code. There are a few common patterns:
- Some IR-related APIs htake an IRUnit* that might be nullptr, and pass
in an incremented iterator as an insertion point. Some old code was
using "&*++I", which in the case of end() only worked by fluke. If
the IRUnit in question inherits from ilist_node_with_parent<>, you can
use "I->getNextNode()". Otherwise, use "List.getNextNode(*I)".
- In most other cases, crashes on &*I just need to check for I==end()
before dereferencing.
- There's also occasional code that sends iterators into a function, and
then starts calling I->getOperand() (or other API). Either check for
end() before the entering the function, or early exit.
Note for if the static_assert with HasObsoleteCustomization is firing
for you:
- r278513 has examples of how to stop using custom sentinel traits.
- r278532 removed ilist_nextprev_traits since no one was using it. See
lld's r278469 for the only migration I needed to do.
Original commit message follows.
----
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.
llvm-svn: 279314
This spiritually reapplies r279012 (reverted in r279052) without the
r278974 parts. The differences:
- Only the HasGetNext trait exists here, so I've only cleaned up (and
tested) it. I still added HasObsoleteCustomization since I know
this will be expanding when r278974 is reapplied.
- I changed the unit tests to use static_assert to catch problems
earlier in the build.
- I added negative tests for the type traits.
Original commit message follows.
----
Change the ilist traits to use decltype instead of sizeof, and add
HasObsoleteCustomization so that additions to this list don't
need to be added in two places.
I suspect this will now work with MSVC, since the trait tested in
r278991 seems to work. If for some reason it continues to fail on
Windows I'll follow up by adding back the #ifndef _MSC_VER.
llvm-svn: 279312
This is a little class template that just builds an inheritance chain of
empty classes. Despite how simple this is, it can be used to really
nicely create ranked overload sets. I've added a unittest as much to
document this as test it. You can pass an object of this type as an
argument to a function overload set an it will call the first viable and
enabled candidate at or below the rank of the object.
I'm planning to use this in a subsequent commit to more clearly rank
overload candidates used for SFINAE. All credit for this technique and
both lines of code here to Richard Smith who was helping me rewrite the
SFINAE check in question to much more effectively capture the intended
set of checks.
llvm-svn: 279197
This reverts commit r279086, reapplying r279084. I'm not sure what I
ran before, because the compile failure for ADTTests reproduced locally.
The problem is that TestRev is calling BidirectionalVector::rbegin()
when the BidirectionalVector is const, but rbegin() is always non-const.
I've updated BidirectionalVector::rbegin() to be callable from const.
Original commit message follows.
--
As a follow-up to r278991, add some tests that check that
decltype(reverse(R).begin()) == decltype(R.rbegin()), and get them
passing by adding std::remove_reference to has_rbegin.
I'm using static_assert instead of EXPECT_TRUE (and updated the other
has_rbegin check from r278991 in the same way) since I figure that's
more helpful.
llvm-svn: 279091
As a follow-up to r278991, add some tests that check that
decltype(reverse(R).begin()) == decltype(R.rbegin()), and get them
passing by adding std::remove_reference to has_rbegin.
I'm using static_assert instead of EXPECT_TRUE (and updated the other
has_rbegin check from r278991 in the same way) since I figure that's
more helpful.
llvm-svn: 279084
Change the ilist traits to use decltype instead of sizeof, and add
HasObsoleteCustomization so that additions to this list don't need to be
added in two places.
I suspect this will now work with MSVC, since the trait tested in
r278991 seems to work. If for some reason it continues to fail on
Windows I'll follow up by adding back the #ifndef _MSC_VER.
llvm-svn: 279012
Duncan found that reverse worked on mutable rbegin(), but the has_rbegin
trait didn't work with a const method. See http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160815/382890.html
for more details.
Turns out this was already solved in clang with has_getDecl. Copied that and made it work for rbegin.
This includes the tests Duncan attached to that thread, including the traits test.
llvm-svn: 278991
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.
llvm-svn: 278974
Summary:
Looking at the implementation, GenericDomTree has more specific
requirements on NodeRef, e.g. NodeRefObject->getParent() should compile,
and NodeRef should be a pointer. We can remove the pointer requirement,
but it seems to have little gain, given the limited use cases.
Also changed GraphTraits<Inverse<Inverse<T>> to be more accurate.
Reviewers: dblaikie, chandlerc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D23593
llvm-svn: 278961
Summary: This is similiar to r278752, where I found that the std::iterator<...> base can be normal.
Reviewers: dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D23527
llvm-svn: 278753
No one is using the capability to implement next and prev another way
(since lld stopped doing it in r278468). Remove the customization point
by moving the API from ilist_nextprev_traits<T> to ilist_node_access.
The old traits class is still useful/necessary API as a target for
friends of node types that inherit privately from ilist_node.
Eventually I plan to either remove it entirely or move the template
parameters to the methods.
(Note: if there's desire to bring back customization of next/prev
pointers in the future (e.g., to pack some bits in there), I think a
traits class like this is an awkward way to accomplish it. Instead, we
should change ilist<T> to be ilist<ilist_node<T>>, and give an extra
template parameter to ilist_node.)
llvm-svn: 278532
Share code for the (mostly problematic) embedded sentinel traits.
- Move the LLVM_NO_SANITIZE("object-size") attribute to
ilist_half_embedded_sentinel_traits and ilist_embedded_sentinel_traits
(previously it spread throughout the code duplication).
- Add an ilist_full_embedded_sentinel_traits which has no UB (but has
the downside of storing the complete node).
- Replace all the custom sentinel traits in LLVM with a declaration of
ilist_sentinel_traits that inherits from one of the embedded sentinel
traits classes.
There are still custom sentinel traits in other LLVM subprojects. I'll
remove those in a follow-up.
Nothing at all should be changing here, this is just rearranging code.
Note that the final goal here is to remove the sentinel traits
altogether, settling on the memory layout of
ilist_half_embedded_sentinel_traits without the UB. This intermediate
step moves the logic into ilist.h.
llvm-svn: 278513
Remove all ilist_iterator to pointer casts. There were two reasons for
casts:
- Checking for an uninitialized (i.e., null) iterator. I added
MachineInstrBundleIterator::isValid() to check for that case.
- Comparing an iterator against the underlying pointer value while
avoiding converting the pointer value to an iterator. This is
occasionally necessary in MachineInstrBundleIterator, since there is
an assertion in the constructors that the underlying MachineInstr is
not bundled (but we don't care about that if we're just checking for
pointer equality).
To support the latter case, I rewrote the == and != operators for
ilist_iterator and MachineInstrBundleIterator.
- The implicit constructors now use enable_if to exclude
const-iterator => non-const-iterator conversions from overload
resolution (previously it was a compiler error on instantiation, now
it's SFINAE).
- The == and != operators are now global (friends), and are not
templated.
- MachineInstrBundleIterator has overloads to compare against both
const_pointer and const_reference. This avoids the implicit
conversions to MachineInstrBundleIterator that assert, instead just
checking the address (and I added unit tests to confirm this).
Notably, the only remaining uses of ilist_iterator::getNodePtrUnchecked
are in ilist.h, and no code outside of ilist*.h directly relies on this
UB end-iterator-to-pointer conversion anymore. It's still needed for
ilist_*sentinel_traits, but I'll clean that up soon.
llvm-svn: 278478
Allow an ilist_iterator to be constructed from an ilist_node, and give
access to the underlying ilist_node as well.
This will be used immediately in lld to support a type-erasure use case.
Longer term, they'll stick around once the iterator is using
ilist_node<NodeTy>* instead of NodeTy*.
llvm-svn: 278467
Summary:
Notice that the data layout is changed: instead of using
std::pair<PointerIntPair<NodeType*, 1>, ChildItTy>, now use
std::pair<NodeRef, Optional<ChildItTy>>.
A NFC but worth noticing change is operator==(), since we only compare
an iterator against end(), it's better to put an assert there and make
people noticed when it fails.
Reviewers: dblaikie, chandlerc
Subscribers: mzolotukhin, llvm-commits
Differential Revision: https://reviews.llvm.org/D23146
llvm-svn: 278437
Summary: Make Optional's behavior the same as the coming std::optional.
Reviewers: dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D23178
llvm-svn: 278397
Summary: make_scope_exit() is described in C++ proposal p0052r2, which uses RAII to do cleanup works at scope exit.
Reviewers: chandlerc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D22796
llvm-svn: 278251
Summary: By generalize the interface, users are able to inject more flexible Node token into the algorithm, for example, a pair of vector<Node>* and index integer. Currently I only migrated SCCIterator to use NodeRef, but more is coming. It's a NFC.
Reviewers: dblaikie, chandlerc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D22937
llvm-svn: 277399
are very handy when parsing text.
They are essentially a combination of startswith and a self-modifying
drop_front, or endswith and drop_back respectively.
Differential Revision: https://reviews.llvm.org/D22723
llvm-svn: 277288
MSVC won't provide the body of this move constructor and assignment
operator, possibly because the copy constructor is banned. Just write
it manually.
llvm-svn: 276685
This prevents StringSwitch from being used with 'auto', which is
important because the inferred type is StringSwitch rather than the
result type. This is a problem because StringSwitch stores addresses
of temporary values rather than copying or moving the value into its
own storage.
This is a compromise that still allows wrapping StringSwitch in other
temporary structures, which (unlike StringSwitch) may be non-trivial
to set up and therefore want to at least be movable. (For an example,
see QueryParser.cpp in clang-tools-extra.)
Changing this uncovered the bug in PassBuilder, also in this patch.
Clang doesn't seem to have any occurrences of the issue.
Re-commit of r276652.
llvm-svn: 276671
...but most importantly, it cannot be used well with 'auto', because
the inferred type is StringSwitch rather than the result type. This
is a problem because StringSwitch stores addresses of temporary
values rather than copying or moving the value into its own storage.
Changing this uncovered the bug in PassBuilder, also in this patch.
Clang doesn't seem to have any occurrences of the issue.
llvm-svn: 276652
This adds versions of operator + and - which are optimized for the LHS/RHS of the
operator being RValue's. When an RValue is available, we can use its storage space
instead of allocating new space.
On code such as ConstantRange which makes heavy use of APInt's over 64-bits in size,
this results in significant numbers of saved allocations.
Thanks to David Blaikie for all the review and most of the code here.
llvm-svn: 276470
This provides an elegant pattern to solve the "construct if not in map
already" problem we have many times in LLVM. Without try_emplace we
either have to rely on a sentinel value (nullptr) or do two lookups.
llvm-svn: 276277
Summary:
Functions like "slice" and "drop_front" sound like they might mutate the
underlying object, but they don't. Warning on unused results would have
saved me an hour yesterday, and I'm sure I'm not the only one.
LLVM and Clang are clean wrt this warning after D22540.
Reviewers: majnemer
Subscribers: sanjoy, chandlerc, llvm-commits
Differential Revision: https://reviews.llvm.org/D22541
llvm-svn: 276058
Summary:
The triple used for this distribution is mips64el-linux-gnuabi64.
Reviewers: sdardis
Subscribers: sdardis, llvm-commits
Differential Revision: https://reviews.llvm.org/D22406
llvm-svn: 275966
Summary: Normally when you do a bitwise operation on an enum value, you
get back an instance of the underlying type (e.g. int). But using this
macro, bitwise ops on your enum will return you back instances of the
enum. This is particularly useful for enums which represent a
combination of flags.
Suppose you have a function which takes an int and a set of flags. One
way to do this would be to take two numeric params:
enum SomeFlags { F1 = 1, F2 = 2, F3 = 4, ... };
void Fn(int Num, int Flags);
void foo() {
Fn(42, F2 | F3);
}
But now if you get the order of arguments wrong, you won't get an error.
You might try to fix this by changing the signature of Fn so it accepts
a SomeFlags arg:
enum SomeFlags { F1 = 1, F2 = 2, F3 = 4, ... };
void Fn(int Num, SomeFlags Flags);
void foo() {
Fn(42, static_cast<SomeFlags>(F2 | F3));
}
But now we need a static cast after doing "F2 | F3" because the result
of that computation is the enum's underlying type.
This patch adds a mechanism which gives us the safety of the second
approach with the brevity of the first.
enum SomeFlags {
F1 = 1, F2 = 2, F3 = 4, ..., F_MAX = 128,
LLVM_MARK_AS_BITMASK_ENUM(F_MAX)
};
void Fn(int Num, SomeFlags Flags);
void foo() {
Fn(42, F2 | F3); // No static_cast.
}
The LLVM_MARK_AS_BITMASK_ENUM macro enables overloads for bitwise
operators on SomeFlags. Critically, these operators return the enum
type, not its underlying type, so you don't need any static_casts.
An advantage of this solution over the previously-proposed BitMask class
[0, 1] is that we don't need any wrapper classes -- we can operate
directly on the enum itself.
The approach here is somewhat similar to OpenOffice's typed_flags_set
[2]. But we skirt the need for a wrapper class (and a good deal of
complexity) by judicious use of enable_if. We SFINAE on the presence of
a particular enumerator (added by the LLVM_MARK_AS_BITMASK_ENUM macro)
instead of using a traits class so that it's impossible to use the enum
before the overloads are present. The solution here also seamlessly
works across multiple namespaces.
[0] http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20150622/283369.html
[1] http://lists.llvm.org/pipermail/llvm-commits/attachments/20150623/073434b6/attachment.obj
[2] https://cgit.freedesktop.org/libreoffice/core/tree/include/o3tl/typed_flags_set.hxx
Reviewers: chandlerc, rsmith
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D22279
llvm-svn: 275292
Summary:
Add renderscript32 and renderscript64 ArchTypes. This is to configure
the ABI requirement on 32-bit RenderScript that 'long' types have 64-bit
size and alignment. 64-bit RenderScript is the same as AArch64, but is
added here for completeness.
Reviewers: echristo, rsmith
Subscribers: aemerson, jfb, rampitec, dschuff, mehdi_amini, llvm-commits, srhines
Differential Revision: http://reviews.llvm.org/D21333
llvm-svn: 274412
re-insertion of entries into the worklist moves them to the end.
This is fairly similar to a SetVector, but helps in the case where in
addition to not inserting duplicates you want to adjust the sequence of
a pop-off-the-back worklist.
I'm not at all attached to the name of this data structure if others
have better suggestions, but this is one that David Majnemer brought up
in IRC discussions that seems plausible.
I've trimmed the interface down somewhat from SetVector's interface
because several things make less sense here IMO: iteration primarily.
I'd prefer to add these back as we have users that need them. My use
case doesn't even need all of what is provided here. =]
I've also included a basic unittest to make sure this functions
reasonably.
Differential Revision: http://reviews.llvm.org/D21866
llvm-svn: 274198
This allows us to query about the endianness without having to
look at DataLayout. The API will be used (and tested) in lld,
in order to find out the endianness of BitcodeFiles.
Briefly discussed with Rafael.
llvm-svn: 274090
Summary:
canCombineSinCosLibcall() would previously combine sin+cos into sincos for
GNUX32/GNUEABI/GNUEABIHF regardless of whether UnsafeFPMath were set or not.
However, GNU would only combine them for UnsafeFPMath because sincos does not
set errno like sin and cos do. It seems likely that this is an oversight.
Reviewers: t.p.northover
Subscribers: t.p.northover, aemerson, llvm-commits, rengolin
Differential Revision: http://reviews.llvm.org/D21431
llvm-svn: 273259
- We lacked a short unique identifier for a statistics, so I renamed the
current "Name" field that just contained the DEBUG_TYPE name of the
current file to DebugType and added a new "Name" field that contains
the C++ identifier of the statistic variable.
- Add the -stats-json option which outputs statistics in json format.
Differential Revision: http://reviews.llvm.org/D20995
llvm-svn: 272826
