Libc++ is used as a system library on macOS and iOS (amongst others). In order
for users to be able to compile a binary that is intended to be deployed to an
older version of the platform, clang provides the
availability attribute <https://clang.llvm.org/docs/AttributeReference.html#availability>_
that can be placed on declarations to describe the lifecycle of a symbol in the
library.
See docs/DesignDocs/AvailabilityMarkup.rst for more information.
Differential Revision: https://reviews.llvm.org/D31739
llvm-svn: 302172
When the libc++ extern template macros were added, the intent was for it
to be possible for consumers of the headers to disable extern templates
(via `-D_LIBCPP_EXTERN_TEMPLATE(...)=`). Unfortunately, support for
specifying function-like macros varies on the command line varies across
compilers (e.g. MSVC doesn't support it at all), and cmake doesn't allow
it for the same reason. Add a non-function macro for this purpose.
The intended use is for libraries which want to use the libc++ headers
without taking a dependency on the libc++ library itself. I can name the
macro something which reflects its intent rather than its behavior (e.g.
`_LIBCPP_HEADER_ONLY`) if desired.
Differential Revision: https://reviews.llvm.org/D31725
llvm-svn: 300246
Summary:
Most classes annotated with _LIBCPP_TYPE_VIS need to have at least some
of their members exported, otherwise we have a lot of link errors when
linking against a libc++ built with hidden visibility. This also makes
_LIBCPP_TYPE_VIS be consistent across platforms, since on Windows it
already exports members.
With this change made, any template methods of a class marked
_LIBCPP_TYPE_VIS will also get default visibility when instantiatied,
which is not desirable for clients of libc++ headers who wish to control
their visibility; this is the same issue as PR30642. Annotate all
problematic methods with an explicit visibility specifier to avoid this.
The problematic methods were found by running bad-visibility-finder [1]
against the libc++ headers after making the _LIBCPP_TYPE_VIS change. The
small methods were marked for inlining; the larger ones hidden.
[1] https://github.com/smeenai/bad-visibility-finder
Reviewers: mclow.lists, EricWF
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D25208
llvm-svn: 296732
When building libc++ with hidden visibility, we want explicit template
instantiations to export members. This is consistent with existing
Windows behavior, and is necessary for clients to be able to link
against a hidden visibility built libc++ without running into lots of
missing symbols.
An unfortunate side effect, however, is that any template methods of a
class with an explicit instantiation will get default visibility when
instantiated, unless the methods are explicitly marked inline or hidden
visibility. This is not desirable for clients of libc++ headers who wish
to control their visibility, and led to PR30642.
Annotate all problematic methods with an explicit visibility specifier
to avoid this. The problematic methods were found by running
https://github.com/smeenai/bad-visibility-finder against the libc++
headers after making the _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS change. The
methods were marked with the new _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
macro, which was created for this purpose.
It should be noted that _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS was originally
intended to expand to default visibility, and was changed to expanding
to default type visibility to fix PR30642. The visibility macro
documentation was not updated accordingly, however, so this change makes
the macro consistent with its documentation again, while explicitly
fixing the methods which resulted in that PR.
Differential Revision: https://reviews.llvm.org/D29157
llvm-svn: 296731
Summary:
This patch implements [P0003R5](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0003r5.html) which removes exception specifications from C++17.
The only changes to the library are removing `set_unexpected`, `get_unexpected`, `unexpected`, and `unexpected_handler`. These functions can be re-enabled in C++17 using `_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS`.
@mclow.lists what do you think about removing stuff is this way?
Reviewers: mclow.lists
Reviewed By: mclow.lists
Subscribers: mclow.lists, cfe-commits
Differential Revision: https://reviews.llvm.org/D28172
llvm-svn: 295406
This covers how to build libc++ for Windows. This allows others to
replicate the MS ABI style build for libc++. It only depends on msvcrt
as it uses the Windows threading model and the Windows ABI and can serve
as an ABI compatible replacement for msvcprt.
llvm-svn: 294705
Summary: On Windows tests that use `_LIBCPP_ASSERT` fail to link because the assertion handler function isn't correctly exported from the libc++ dylib. This patch fixes the dll import/export issues by introducing a new visibility macro `_LIBCPP_EXTERN_VIS` for use on external variables.
Reviewers: compnerd, smeenai, EricWF
Reviewed By: EricWF
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D28728
llvm-svn: 292158
Clang recently added a `diagnose_if(cond, msg, type)` attribute
which can be used to generate diagnostics when `cond` is a constant
expression that evaluates to true. Otherwise no attribute has no
effect.
This patch adds _LIBCPP_DIAGNOSE_ERROR/WARNING macros which
use this new attribute. Additionally this patch implements
a diagnostic message when a non-const-callable comparator is
given to a container.
Note: For now the warning version of the diagnostic is useless
within libc++ since warning diagnostics are suppressed by the
system header pragma. I'm going to work on fixing this.
llvm-svn: 291961
Summary:
This patch attempts to clean up the macro configuration mess in `<__threading_support>`, specifically the mess involving external threading variants. Additionally this patch adds design documentation for `<__threading_support>` and the configuration macros it uses.
The primary change in this patch is separating the idea of an "external API" provided by `<__external_threading>` and the idea of having an external threading library. Now `_LIBCPP_HAS_THREAD_API_EXTERNAL` means that libc++ should use `<__external_threading>` and that the header is expected to exist. Additionally the new macro `_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL` is now used to configure for using an "external library" with the default threading API.
Reviewers: compnerd, rmaprath
Subscribers: smeenai, cfe-commits, mgorny
Differential Revision: https://reviews.llvm.org/D28316
llvm-svn: 291275
The name _LIBCPP_TYPE_VIS_ONLY is no longer accurate because both
_LIBCPP_TYPE_VIS and _LIBCPP_TYPE_VIS_ONLY expand to
__attribute__((__type_visibility__)) with Clang. The only remaining difference
is that _LIBCPP_TYPE_VIS_ONLY can be applied to templates whereas
_LIBCPP_TYPE_VIS cannot (due to dllimport/dllexport not being allowed on
templates).
This patch renames _LIBCPP_TYPE_VIS_ONLY to _LIBCPP_TEMPLATE_VIS.
llvm-svn: 291035
This patch implements changes to allow _LIBCPP_ASSERT to throw on failure
instead of aborting. The main changes needed to do this are:
1. Change _LIBCPP_ASSERT to call a handler via a replacable function pointer
instead of calling abort directly. Additionally this patch implements two
handler functions, one which aborts and another that throws an exception.
2. Add _NOEXCEPT_DEBUG macro for disabling noexcept spec on function which
contain _LIBCPP_ASSERT. This is required in order to prevent assertion
failures throwing through a noexcept function. This macro has no effect
unless _LIBCPP_DEBUG_USE_EXCEPTIONS is defined.
Having a non-aborting _LIBCPP_ASSERT is very important to allow sane testing of
debug mode. Currently we can only have one test case per file, since the test
case will cause the program to abort. Testing debug mode this way would require
thousands of test files, most of which would be 95% boiler plate. I don't think
this is a feasible strategy. Fortunately using a throwing debug handler solves
these issues.
Additionally this patch rewrites the documentation for debug mode.
llvm-svn: 290651
This patch removes libc++'s tuple extension which allowed it to be
constructed from fewer initializers than elements; with the remaining
elements being default constructed. However the implicit version of
this extension breaks conforming code. For example:
int fun(std::string);
int fun(std::tuple<std::string, int>);
int x = fun("hello"); // ambigious
Because existing code may already depend on this extension it can be re-enabled
by defining _LIBCPP_ENABLE_TUPLE_IMPLICIT_REDUCED_ARITY_EXTENSION.
Note that the explicit version of this extension is still supported,
although it's somewhat less useful than the implicit one.
llvm-svn: 289158
It's useful to be able to disable visibility annotations entirely; for
example, if we're building libc++ static to include in another library,
and we don't want any libc++ functions getting exported out of that
library. This is a generalization of _LIBCPP_DISABLE_DLL_IMPORT_EXPORT.
Differential Revision: https://reviews.llvm.org/D26934
llvm-svn: 288690
This is a generalization of `_LIBCPP_NEW_DELETE_VIS`; the new macro name
captures the semantics better, and also allows us to get rid of the
`_WIN32` check in `include/new`. No functional change.
Differential Revision: https://reviews.llvm.org/D26702
llvm-svn: 287164
This prevent the symbols from being both externally available and hidden, which
causes them to be linked incorrectly. This is only a problem when the address
of the function is explicitly taken since it will always be inlined otherwise.
This patch fixes the issues that caused r285456 to be reverted, and can
now be reapplied.
llvm-svn: 285531
The behavior of this macro actually needs to apply universally on
Windows and not just when using the Microsoft CRT. Update the macro
definition and documentation accordingly.
Differential Revision: https://reviews.llvm.org/D25145
llvm-svn: 284016
Replace a stale reference to cxx_EXPORTS with _LIBCPP_BUILDING_LIBRARY,
and clarify why the operator new and delete family of functions are
marked dllexport when building but *not* dllimport when including the
header externally.
The new code is identical to the intent of the old code (and would be
functionally equivalent were cxx_EXPORTS still defined when building
libc++). The overall behavior is not ideal, since Microsoft's operator
new and delete functions will get called instead of libc++'s, but I
think consistently calling msvcrt's functions is better than either
calling msvcrt's or libc++'s functions depending on header inclusion.
Differential Revision: https://reviews.llvm.org/D25042
llvm-svn: 282644
On Windows, marking an `extern template class` declaration as exported
actually forces an instantiation, which is not the desired behavior.
Instead, the actual explicit instantiations need to be exported.
Differential Revision: https://reviews.llvm.org/D24679
llvm-svn: 281925
Summary:
This patch fixes a number of problems with the visibility macros across GCC (on Unix) and Windows (DLL import/export semantics). All of the visibility macros are now documented under `DesignDocs/VisibilityMacros.rst`. Now I'll no longer forget the subtleties of each!
This patch adds two new visibility macros:
* `_LIBCPP_ENUM_VIS` for controlling the typeinfo of enum types. Only Clang supports this.
* `_LIBCPP_EXTERN_TEMPLATE_TYPE_VIS` for redefining visibility on explicit instantiation declarations. Clang and Windows require this.
After applying this patch GCC only emits one -Wattribute warning opposed to 30+.
Reviewers: mclow.lists, EricWF
Subscribers: beanz, mgorny, cfe-commits
Differential Revision: https://reviews.llvm.org/D24602
llvm-svn: 281673
When libc++experimental was originally created it was empty and therefore there
was no reason to install it. Now that the library contains
<experimental/memory_resource> and <experimental/filesystem> there is a good
reason to install it.
Specifically this patch enables the installation whenever LIBCXX_INSTALL_LIBRARY
is true and LIBCPP_ENABLE_EXPERIMENTAL_LIBRARY is true.
llvm-svn: 280773
This patch enables the `cxx-benchmarks` target by default. Note that the target
still has to be manually invoked since it isn't included in the default 'make'
rule.
This patch also gets the benchmarks building w/ GCC. The build previously
required the '-stdlib=libc++' flag but upstream patches to Google Benchmark
now allow the library to build w/ libc++ and GCC.
These changes should make the benchmarks easier to build and test.
llvm-svn: 279999
This change allows building both shared and static version of libc++
in a single build, sharing object files between both versions.
Differential Revision: https://reviews.llvm.org/D23232
llvm-svn: 278068
Summary:
This patch does the following:
1. Checks in a copy of the Google Benchmark library into the libc++ repo under `utils/google-benchmark`.
2. Teaches libc++ how to build Google Benchmark against both (A) in-tree libc++ and (B) the platforms native STL.
3. Allows performance benchmarks to be built as part of the libc++ build.
Building the benchmarks (and Google Benchmark) is off by default. It must be enabled using the CMake option `-DLIBCXX_INCLUDE_BENCHMARKS=ON`. When this option is enabled the tests under `libcxx/benchmarks` can be built using the `libcxx-benchmarks` target.
On Linux platforms where libstdc++ is the default STL the CMake option `-DLIBCXX_BUILD_BENCHMARKS_NATIVE_STDLIB=ON` can be used to build each benchmark test against libstdc++ as well. This is useful for comparing performance between standard libraries.
Support for benchmarks is currently very minimal. They must be manually run by the user and there is no mechanism for detecting performance regressions.
Known Issues:
* `-DLIBCXX_INCLUDE_BENCHMARKS=ON` is only supported for Clang, and not GCC, since the `-stdlib=libc++` option is needed to build Google Benchmark.
Reviewers: danalbert, dberlin, chandlerc, mclow.lists, jroelofs
Subscribers: chandlerc, dberlin, tberghammer, danalbert, srhines, hfinkel
Differential Revision: https://reviews.llvm.org/D22240
llvm-svn: 276049
Add the completed std::experimental::filesystem implementation and tests.
The implementation supports C++11 or newer.
The TS is built as part of 'libc++experimental.a'. Users of the TS need to
manually link this library. Building and testing the TS can be disabled using
the CMake option '-DLIBCXX_ENABLE_FILESYSTEM=OFF'.
Currently 'libc++experimental.a' is not installed by default. To turn on the
installation of the library use '-DLIBCXX_INSTALL_EXPERIMENTAL_LIBRARY=ON'.
llvm-svn: 273034
Summary:
Currently much of the libcxx website is duplicated between the old www/ documentation and newer Sphinx docs. This patch changes the main libc++ webpage so that it links to the new documentation where possible. This means removing numerous sections from the landing page.
@mclow.lists What do you think?
Reviewers: mclow.lists
Subscribers: cfe-commits, mclow.lists
Differential Revision: http://reviews.llvm.org/D19250
llvm-svn: 271469
Eric Fiselier