This patch is fairly large and contains a number of changes. The main change
is teaching '__hash_table' how to handle '__hash_value_type'. Unfortunately
this change is a rampant layering violation, but it's required to make
unordered_map conforming without re-writing all of __hash_table.
After this change 'unordered_map' can delegate to '__hash_table' in almost all cases.
The major changes found in this patch are:
* Teach __hash_table to differentiate between the true container value type
and the node value type by introducing the "__container_value_type" and
"__node_value_type" typedefs. In the case of unordered_map '__container_value_type'
is 'pair<const Key, Value>' and '__node_value_type' is '__hash_value_type'.
* Switch almost all overloads in '__hash_table' previously taking 'value_type'
(AKA '__node_value_type) to take '__container_value_type' instead. Previously
'pair<K, V>' would be implicitly converted to '__hash_value_type<K, V>' because
of the function signature.
* Add '__get_key', '__get_value', '__get_ptr', and '__move' static functions to
'__key_value_types'. These functions allow '__hash_table' to unwrap
'__node_value_type' objects into '__container_value_type' and its sub-parts.
* Pass '__hash_value_type::__value_' to 'a.construct(p, ...)' instead of
'__hash_value_type' itself. The C++14 standard requires that 'a.construct()'
and 'a.destroy()' are only ever instantiated for the containers value type.
* Remove '__hash_value_type's constructors and destructors. We should never
construct an instance of this type.
(TODO this is UB but we already do it in plenty of places).
* Add a generic "try-emplace" function to '__hash_table' called
'__emplace_unique_key_args(Key const&, Args...)'.
The following changes were done as cleanup:
* Introduce the '_LIBCPP_CXX03_LANG' macro to be used in place of
'_LIBCPP_HAS_NO_VARIADICS' or '_LIBCPP_HAS_NO_RVALUE_REFERENCE'.
* Cleanup C++11 only overloads that assume an incomplete C++11 implementation.
For example this patch removes the __construct_node overloads that do
manual pack expansion.
* Forward 'unordered_map::emplace' to '__hash_table' and remove dead code
resulting from the change. This includes almost all
'unordered_map::__construct_node' overloads.
The following changes are planed for future revisions:
* Fix LWG issue #2469 by delegating 'unordered_map::operator[]' to use
'__emplace_unique_key_args'.
* Rewrite 'unordered_map::try_emplace' in terms of '__emplace_unique_key_args'.
* Optimize '__emplace_unique' to call '__emplace_unique_key_args' when possible.
This prevent unneeded allocations when inserting duplicate entries.
The additional follow up work needed after this patch:
* Respect the lifetime rules for '__hash_value_type' by actually constructing it.
* Make '__insert_multi' act similar to '__insert_unique' for objects of type
'T&' and 'T const &&' with 'T = __container_value_type'.
llvm-svn: 260513
This time I kept <ext/hash_map> working!
This patch is the first in a series of patches that's meant to better
support unordered_map. unordered_map has a special "value_type" that
differs from pair<const Key, Value>. In order to meet the EmplaceConstructible
and CopyInsertable requirements we need to teach __hash_table about this
special value_type.
This patch creates a "__hash_node_types" traits class that contains
all of the typedefs needed by the unordered containers and it's iterators.
These typedefs include ones for each node type and node pointer type,
as well as special typedefs for "unordered_map"'s value type.
As a result of this change all of the unordered containers now all support
incomplete types.
As a drive-by fix I changed the difference_type in __hash_table to always
be ptrdiff_t. There is a corresponding change to size_type but it cannot
take affect until an ABI break.
This patch will be followed up shortly with fixes for various unordered_map
bugs and problems.
llvm-svn: 260431
This patch is the first in a series of patches that's meant to better
support unordered_map. unordered_map has a special "value_type" that
differs from pair<const Key, Value>. In order to meet the EmplaceConstructible
and CopyInsertable requirements we need to teach __hash_table about this
special value_type.
This patch creates a "__hash_node_types" traits class that contains
all of the typedefs needed by the unordered containers and it's iterators.
These typedefs include ones for each node type and node pointer type,
as well as special typedefs for "unordered_map"'s value type.
As a result of this change all of the unordered containers now all support
incomplete types.
As a drive-by fix I changed the difference_type in __hash_table to always
be ptrdiff_t. There is a corresponding change to size_type but it cannot
take affect until an ABI break.
This patch will be followed up shortly with fixes for various unordered_map
fixes.
llvm-svn: 260012
Rename the version of __construct_node() that takes a hash as an
argument to __construct_node_hash(), and use perfect-forwarding when
Rvalue references are available. The primary motivation is to allow
other types through, since unordered_map's value_type is different from
__hash_table's value_type -- a follow-up will take advantage of this --
but the rename is general "goodness".
There should be no functionality change here (aside from enabling the
follow-up).
llvm-svn: 258511
This change moves visibility attributes from out-of-class method
definitions to in-class declaration. This is needed for a switch to
attribute((internal_linkage)) (see http://reviews.llvm.org/D13925)
which can only appear on the first declaration.
This change does not touch istream/ostream/streambuf. They are
handled separately in http://reviews.llvm.org/D14409.
llvm-svn: 252385
Summary:
Throughout the libc++ headers, there are a few instances where
_VSTD::move() is used to return a local variable. Howard commented in
r189039 that these were there "for non-obvious reasons such as to help
things limp along in C++03 language mode".
However, when compiling these headers with warnings on, and in C++11 or
higher mode (like we do in FreeBSD), they cause the following complaints
about pessimizing moves:
In file included from tests.cpp:26:
In file included from tests.hpp:29:
/usr/include/c++/v1/map:1368:12: error: moving a local object in a return statement prevents copy elision [-Werror,-Wpessimizing-move]
return _VSTD::move(__h); // explicitly moved for C++03
^
/usr/include/c++/v1/__config:368:15: note: expanded from macro '_VSTD'
#define _VSTD std::_LIBCPP_NAMESPACE
^
Attempt to fix this by adding a _LIBCPP_EXPLICIT_MOVE() macro to
__config, which gets defined to _VSTD::move for pre-C++11, and to
nothing for C++11 and later.
I am not completely satisfied with the macro name (I also considered
_LIBCPP_COMPAT_MOVE and some other variants), so suggestions are
welcome. :)
Reviewers: mclow.lists, howard.hinnant, EricWF
Subscribers: arthur.j.odwyer, cfe-commits
Differential Revision: http://reviews.llvm.org/D11394
llvm-svn: 245421
Although CMake adds warning flags, they are ignored in the libc++ headers
because the headers '#pragma system header' themselves.
This patch disables the system header pragma when building libc++ and fixes
the warnings that arose.
The warnings fixed were:
1. <memory> - anonymous structs are a GNU extension
2. <functional> - anonymous structs are a GNU extension.
3. <__hash_table> - Embedded preprocessor directives have undefined behavior.
4. <string> - Definition is missing noexcept from declaration.
5. <__std_stream> - Unused variable.
llvm-svn: 242623
Summary:
when `unordered_set::insert(value_type&&)` was called it would be treated like `unordered_set::emplace(Args&&)` and it would allocate and construct a node before trying to insert it.
This caused unnecessary allocations when the value was already in the set. This patch adds an overload to `__hash_table::__insert_unique` that specifically handles `value_type&&` more link `value_type const &`.
This patch also adds a single unified insert function for values into `__hash_table` called `__insert_unique_value` that handles the cases for `__insert_unique(value_type&&)` and `__insert_unique(value_type const &)`.
This patch fixes PR12999: http://llvm.org/bugs/show_bug.cgi?id=12999.
Reviewers: mclow.lists, titus, danalbert
Reviewed By: danalbert
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D7570
llvm-svn: 239666
Visual Studio's SAL extension uses a macro named __deallocate. This macro is
used pervasively, and gets included through various different ways. This
conflicts with the similarly named interfaces in libc++. Introduce a undef
header similar to __undef_min_max to handle this. This fixes a number of errors
due to the macro replacing the function name.
llvm-svn: 229162
Things done in this patch:
1. Make __debug include __config since it uses macros from it.
2. The current method of defining _LIBCPP_ASSERT is prone to redefinitions. Move
the null _LIBCPP_ASSERT definition into the __debug header to prevent this.
3. Remove external <__debug> include gaurds. <__debug> guards almost all of its
contents internally. There is no reason to be doing it externally.
This patch should not change any functionality.
llvm-svn: 215332
1. I had been detecting and trapping iterator == and \!= among iterators
in different containers as an error. But the trapping itself is actually
an error.
Consider:
#include <iostream>
#include <vector>
#include <algorithm>
template <class C>
void
display(const C& c)
{
std::cout << "{";
bool first = true;
for (const auto& x : c)
{
if (\!first)
std::cout << ", ";
first = false;
std::cout << x;
}
std::cout << "}\n";
}
int
main()
{
typedef std::vector<int> V;
V v1 = {1, 3, 5};
V v2 = {2, 4, 6};
display(v1);
display(v2);
V::iterator i = std::find(v1.begin(), v1.end(), 1);
V::iterator j = std::find(v2.begin(), v2.end(), 2);
if (*i == *j)
i = j; // perfectly legal
// ...
if (i \!= j) // the only way to check
v2.push_back(*i);
display(v1);
display(v2);
}
It is legal to assign an iterator from one container to another of the
same type. This is required to work. One might want to test whether or
not such an assignment had been made. The way one performs such a check
is using the iterator's ==, \!= operator. This is a logical and necessary
function and does not constitute an error.
2. I had a header circular dependence bug when _LIBCPP_DEBUG2 is defined.
This caused a problem in several of the libc++ tests.
Fixed.
3. There is a serious problem when _LIBCPP_DEBUG2=1 at the moment in that
std::basic_string is inoperable. std::basic_string uses __wrap_iterator
to implement its iterators. __wrap_iterator has been rigged up in debug
mode to support vector. But string hasn't been rigged up yet. This means
that one gets false positives when using std::string in debug mode. I've
upped std::string's priority in www/debug_mode.html.
llvm-svn: 187636
There are actually two debug modes:
1. -D_LIBCPP_DEBUG2 or -D_LIBCPP_DEBUG2=1
This is a relatively expensive debug mode, but very thorough. This is normally what you want to debug with, but may turn O(1) operations into O(N) operations.
2. -D_LIBCPP_DEBUG2=0
This is "debug lite." Only preconditions that can be checked with O(1) expense are checked. For example range checking on an indexing operation. But not iterator validity.
llvm-svn: 187369
unordered_set, however it is not complete yet for unordered_multiset,
unordered_map or unordered_multimap. There has been a lot of work done
for these other three containers, however that work was done just to
keep all of the tests passing.
You can try this out with -D_LIBCPP_DEBUG2. You will have to link to a
libc++.dylib that has been compiled with src/debug.cpp. So far, vector
(but not vector<bool>), list, and unordered_set are treated. I hope to
get the other three unordered containers up fairly quickly now that
unordered_set is done.
The flag _LIBCPP_DEBUG2 will eventually be changed to _LIBCPP_DEBUG, but
not today. This is my second effort at getting debug mode going for
libc++, and I'm not quite yet ready to throw all of the work under the
first attempt away.
The basic design is that all of the debug information is kept in a
central database, instead of in the containers. This has been done as
an attempt to have debug mode and non-debug mode be ABI compatible with
each other. There are some circumstances where if you construct a
container in an environment without debug mode and pass it into debug
mode, the checking will get confused and let you know with a readable
error message. Passing containers the other way: from debug mode out to
a non-debugging mode container should be 100% safe (at least that is the
goal).
llvm-svn: 186991
Original change:
Destruct elements of hash tables when removing individual entries from
the hash_table. I think this is the correct solution to PR10507, but I'm
not sure since this is a little bit cargo-culted. Howard, please review.
llvm-svn: 136576
the hash_table. I think this is the correct solution to PR10507, but I'm
not sure since this is a little bit cargo-culted. Howard, please review.
llvm-svn: 136546
Eric Fiselier