Summary:
Freestanding is *weird*. The standard allows it to differ in a bunch of odd
manners from regular C++, and the committee would like to improve that
situation. I'd like to make libc++ behave better with what freestanding should
be, so that it can be a tool we use in improving the standard. To do that we
need to try stuff out, both with "freestanding the language mode" and
"freestanding the library subset".
Let's start with the super basic: run the libc++ tests in freestanding, using
clang as the compiler, and see what works. The easiest hack to do this:
In utils/libcxx/test/config.py add:
self.cxx.compile_flags += ['-ffreestanding']
Run the tests and they all fail.
Why? Because in freestanding `main` isn't special. This "not special" property
has two effects: main doesn't get mangled, and main isn't allowed to omit its
`return` statement. The first means main gets mangled and the linker can't
create a valid executable for us to test. The second means we spew out warnings
(ew) and the compiler doesn't insert the `return` we omitted, and main just
falls of the end and does whatever undefined behavior (if you're luck, ud2
leading to non-zero return code).
Let's start my work with the basics. This patch changes all libc++ tests to
declare `main` as `int main(int, char**` so it mangles consistently (enabling us
to declare another `extern "C"` main for freestanding which calls the mangled
one), and adds `return 0;` to all places where it was missing. This touches 6124
files, and I apologize.
The former was done with The Magic Of Sed.
The later was done with a (not quite correct but decent) clang tool:
https://gist.github.com/jfbastien/793819ff360baa845483dde81170feed
This works for most tests, though I did have to adjust a few places when e.g.
the test runs with `-x c`, macros are used for main (such as for the filesystem
tests), etc.
Once this is in we can create a freestanding bot which will prevent further
regressions. After that, we can start the real work of supporting C++
freestanding fairly well in libc++.
<rdar://problem/47754795>
Reviewers: ldionne, mclow.lists, EricWF
Subscribers: christof, jkorous, dexonsmith, arphaman, miyuki, libcxx-commits
Differential Revision: https://reviews.llvm.org/D57624
llvm-svn: 353086
Refactor the get_llvm_lit_path() logic to respect LLVM_EXTERNAL_LIT,
and require the fallback to be defined explicitly
as LLVM_DEFAULT_EXTERNAL_LIT. This fixes building libcxx standalone
after r346888.
The old logic was using LLVM_EXTERNAL_LIT both as user-defined cache
variable and an optional pre-definition of default value from caller
(e.g. libcxx). It included a hack to make this work by assigning
the value back and forth but it was fragile and stopped working
in libcxx.
The new logic is simpler and more transparent. Default value is
provided in a separate variable, and used only when user-specified
variable is empty (i.e. not overriden).
Differential Revision: https://reviews.llvm.org/D57282
llvm-svn: 352374
The check_library_exists CMake uses a custom symbol definition. This
is a problem when checking for C library symbols because Clang
recognizes many of them as builtins, and returns the
-Wbuiltin-requires-header (or -Wincompatible-library-redeclaration)
error. When building with -Werror which is the default, this causes
the check_library_exists check fail making the build think that C
library isn't available.
To avoid this issue, we should use a symbol that isn't recognized by
Clang and wouldn't cause the same issue. __libc_start_main seems like
reasonable choice that fits the bill.
Differential Revision: https://reviews.llvm.org/D57142
llvm-svn: 352341
This is needed when cross-compiling for a different target since
CFLAGS may contain additional flags like -resource-dir which
change the location in which compiler-rt builtins are found.
Differential Revision: https://reviews.llvm.org/D54371
llvm-svn: 346820
This patch adds the cxx-benchmark-unittests target so we can start
getting test coverage on the benchmarks, including building with
sanitizers. Because we're only looking for test-coverage, the benchmarks
run for the shortest time possible, and in parallel.
The target is excluded from all by default. It only
builds and runs the libcxx configurations of the benchmarks, and not
any versions built against the systems native standard library.
llvm-svn: 346811
This avoids duplicate directories when the filename includes path.
Fixes PR39145
Differential Revision: https://reviews.llvm.org/D52762
llvm-svn: 343753
Although libc++ doesn't yet support Windows we still have Windows
builders to track our progress.
Currently the clang-cl configuration seems broken because it doesn't
support -std=c++11 and instead requires /std:c++11. This patch attempts
to fix this.
llvm-svn: 343431
This is a refinement on r337833. Previously we were installing two
copies of c++abi headers in libc++ build directory, one in
include/c++build and another one in include/c++/v1. However, the
second copy is unnecessary when building libc++ standalone.
Differential Revision: https://reviews.llvm.org/D49752
llvm-svn: 337979
This is an alternative approach to r337727 which broke the build
because libc++ headers were copied into the location outside of
directories used by Clang. This change sets LIBCXX_HEADER_DIR to
different values depending on whether libc++ is being built as
part of LLVM w/ per-target multiarch runtime, LLVM or standalone.
Differential Revision: https://reviews.llvm.org/D49711
llvm-svn: 337833
Currently it's possible to select whether to statically link unwinder
or the C++ ABI library, but this option applies to both the shared
and static library. However, in some scenarios it may be desirable to
only statically link unwinder and C++ ABI library into static C++
library since for shared C++ library we can rely on dynamic linking
and linker scripts. This change enables selectively enabling or
disabling statically linking only to shared or static library.
Differential Revision: https://reviews.llvm.org/D49502
llvm-svn: 337668
This is a follow-up to r335809 and r337118. While libc++ headers are now
installed into the right location in both standard as well as multiarch
runtimes layout, turned out C++ ABI headers are still installed into the
old location in the latter case. This change addresses that.
Differential Revision: https://reviews.llvm.org/D49584
llvm-svn: 337630
This change adds a support for multiarch style runtimes layout, so in
addition to the existing layout where runtimes get installed to:
lib/clang/$version/lib/$os
Clang now allows runtimes to be installed to:
lib/clang/$version/$target/lib
This also includes libc++, libc++abi and libunwind; today those are
assumed to be in Clang library directory built for host, with the
new layout it is possible to install libc++, libc++abi and libunwind
into the runtime directory built for different targets.
The use of new layout is enabled by setting the
LLVM_ENABLE_RUNTIME_TARGET_DIR CMake variable and is supported by both
projects and runtimes layouts. The runtimes CMake build has been further
modified to use the new layout when building runtimes for multiple
targets.
Differential Revision: https://reviews.llvm.org/D45604
llvm-svn: 335809
The paths output from llvm-config --cmakedir and from clang
--print-libgcc-file-name can contain backslashes, while CMake
can't handle the paths in this form.
This matches what compiler-rt already does (since SVN r203789
and r293195).
Differential Revision: https://reviews.llvm.org/D48356
llvm-svn: 335172
Using file(COPY FILE...) has several downsides. Since the file command
is only executed at configuration time, any changes to headers made
after the initial CMake execution are ignored. This can lead to subtle
errors since the just built Clang will be using stale libc++ headers.
Furthermore, since the headers are copied prior to executing the build
system, this may hide missing dependencies on libc++ from other LLVM
components.
This changes replaces the use of file(COPY FILE...) command with a
custom command and target which addresses all aforementioned issues and
matches the implementation already used by other LLVM components that
also install headers like Clang builtin headers.
Differential Revision: https://reviews.llvm.org/D44773
llvm-svn: 334468
Using file(COPY FILE...) has several downsides. Since the file command
is only executed at configuration time, any changes to headers made
after the initial CMake execution are ignored. This can lead to subtle
errors since the just built Clang will be using stale libc++ headers.
Furthermore, since the headers are copied prior to executing the build
system, this may hide missing dependencies on libc++ from other LLVM
components.
This changes replaces the use of file(COPY FILE...) command with a
custom command and target which addresses all aforementioned issues and
matches the implementation already used by other LLVM components that
also install headers like Clang builtin headers.
Differential Revision: https://reviews.llvm.org/D44773
llvm-svn: 329544
When libcxx is built in tree for a host which requires libatomic, LLVM's
configuration steps will determine it is required and add it to
CMAKE_REQUIRED_LIBRARIES. When libcxx is later configured, it tests if it
has C++ atomics without libatomic. The test erroneously passes as libatomic
is already part of the set of required libraries.
In turn, a number of the atomic tests will fail as they require libatomic
but the test suite is configured not to use libatomic.
Address this by always dropping libatomic from the set of required libraries
before determining if LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB is true,
then restoring the set of required libraries.
Reviewers: EricWF
Differential Revision: https://reviews.llvm.org/D43509
llvm-svn: 329167
Previously, the install command for the cxxabi headers specified
the wrong component, and therefore they were not being included
in the install-cxx command.
This patch corrects the component name.
llvm-svn: 318989
Despite a strong CMake warning that this is an unsupported
libcxx build configuration, some bots still rely on being
able to check out lit and libcxx independently with no
LLVM sources, and then run lit against libcxx.
A previous patch broke that workflow, so this is making it work
again. Unfortunately, it breaks generation of the llvm-lit
script for libcxx, but we will just have to live with that until
a solution is found that allows libcxx to make more use of
llvm build pieces. libcxx can still run tests by using the
ninja check target, or by running lit.py directly against the
build tree or source tree.
Differential Revision: https://reviews.llvm.org/D38057
llvm-svn: 313763
After speaking with the libcxx owners, they agreed that this is
a bug in the bot that needs to be fixed by the bot owners, and
the CMake changes are correct.
llvm-svn: 313643
This reverts commit 4ad71811d45268d81b60f27e3b8b2bcbc23bd7b9.
There is a bot that is checking out libcxx and lit with nothing
else and then running lit.py against the test tree. Since there's
no LLVM source tree, there's no LLVM CMake. CMake actually
reports this as a warning saying unsupported libcxx configuration,
but I guess someone is depending on it anyway.
llvm-svn: 313607
This is going to be used by the runtime build in the multi-target
setup to allow using different install prefix for each target.
Differential Revision: https://reviews.llvm.org/D33762
llvm-svn: 307615
CMake has the problem with the single dash variant because of the
space, so use the double dash with equal sign version. We also
don't have to pass the target triple when checking for compiler-rt
since that flag is already included in compile flags now.
Differential Revision: https://reviews.llvm.org/D32068
llvm-svn: 300409
We're using -nodefaultlibs to avoid the dependency on C++ library
when using check_cxx_compiler_flag, and as such we cannot use
check_cxx_compiler_flag to check the availability of -nodefaultlibs
itself.
llvm-svn: 299711
When compiler-rt is requested, we should attempt to link compiler-rt
builtins library rather than gcc_s.
Differential Revision: https://reviews.llvm.org/D31617
llvm-svn: 299599
Summary:
mingw64 has lots of default libs that libc++ and its test programs
should link against.
With this patch, cmake now runs successfully with GCC on Windows.
Reviewers: mati865, EricWF
Subscribers: mgorny, cfe-commits
Differential Revision: https://reviews.llvm.org/D31518
llvm-svn: 299144
Clang doesn't produce gcov compatible coverage files. This
causes lcov to break because it uses gcov by default. This
patch switches lcov to use llvm-cov as the gcov-tool.
Unfortunatly llvm-cov doesn't provide a gcov like interface by
default so it won't work with lcov. However `llvm-cov gcov` does.
For this reason we generate 'llvm-cov-wrapper' script that always
passes the gcov flag.
llvm-svn: 297553
This recommits r294707 with additional fixes. The main difference is
libc++ now correctly builds without any ABI library.
exception.cpp is a bloody mess. It's full of confusing #ifdef branches for
each different ABI library we support, and it's getting unmaintainable.
This patch breaks down exception.cpp into multiple different header files,
roughly one per implementation. Additionally it moves the definitions of
exceptions in new.cpp into the correct implementation header.
This patch also removes an unmaintained libc++abi configuration.
This configuration may still be used by Apple internally but there
are no other possible users. If it turns out that Apple still uses
this configuration internally I will re-add it in a later commit.
See http://llvm.org/PR31904.
llvm-svn: 294730
This patch contains multiple cleanups and fixes to better support building on
Windows.
* [Test] Fix handling of library runtime search paths by correctly adding them
to the PATH variable when running the tests.
* [Test] Don't explicitly force "--target=i686-pc-windows" when running the
test suite. Clang++ seems to deduce the correct target.
* [Test] Fix `.sh.cpp` tests on Windows by properly escaping flags used in
shell commands. Specifically windows style paths which included spaces
were causing these tests to fail.
* [CMake] Add "vcruntime" to the list of supported C++ ABI libraries in CMake, and
teach the test suite how to handle it. For now libc++ defaults to using
"vcruntime" on Windows except when libc++abi is in tree; That is probably
a bug and should be changed to always use vcruntime, at least for now.
* [Misc] Move the "c++-build" include directory to the libc++ binary dir
instead of the top level project dir and rename it "c++build". This is just
misc cleanup. Libc++ shouldn't be creating internal build files and directories
at the top-level projects root.
* [Misc] Build type_info's destructor when building for MSVC. This is a temporary
work around to prevent link errors until we have a proper type_info
implementation.
llvm-svn: 292157
Summary:
This patch attempts to fix the libc++ build/link so that it doesn't use an default C++ libraries on Windows. This is needed to prevent linking to MSVC's STL library.
Additionally this patch changes libc++ so that it is always linked with the non-debug DLL's (e.g. `/MD`). This is needed so that the test suite can correctly link the same libraries without needing to know which configuration `c++.dll` was linked with.
Reviewers: compnerd, rnk, majnemer, kimgr, awson, halyavin, smeenai
Subscribers: cfe-commits, mgorny
Differential Revision: https://reviews.llvm.org/D28441
llvm-svn: 292001
This patch adjusts the out-of-tree CMake configuration so that
the stderr output is ignored when an old llvm-config is found
that doesn't support --cmakedir.
llvm-svn: 291991
This is to make sure this check is called even when building as
part of LLVM runtimes when we are doing standalone but not out of
tree build.
Differential Revision: https://reviews.llvm.org/D28392
llvm-svn: 291592
Use the new --cmakedir option to obtain LLVM_CMAKE_PATH straight from
llvm-config. Fallback to local reconstruction if llvm-config does not
support this option.
llvm-svn: 291508
This patch re-commits a previous attempt to support building libc++ w/o
an ABI library. That patch was originally reverted because:
1) It forgot to teach the test suite about "default" ABI libraries.
2) Some LLVM builders don't clear the CMake cache between builds. The previous
patch caused those builders to fail since their old cache entry for
LIBCXX_CXX_ABI="" is no longer valid.
The updated patch addresses both issues. It works around (2) by adding
a hack to force the builders to update their cache entries. The hack will
be removed shortly once all LLVM builders have run.
Original commit message
-----------------------
Typically libc++ uses libc++abi or libcxxrt to provide the ABI and runtime bits
of the C++ STL. However we also support building w/o an ABI library entirely.
This patch fixes building libc++ w/o an ABI library (and incorporates the
`~type_info()` fix in D28211).
The main changes in this patch are:
1) Add `-DLIBCXX_CXX_ABI=default` instead of using the empty string to mean "default".
2) Fix CMake bits which treated "none" as "default" on OS X.
3) Teach the source files to respect `-D_LIBCPP_BUILDING_HAS_NO_ABI_LIBRARY`.
4) Define ~type_info() when _LIBCPP_BUILDING_HAS_NO_ABI_LIBRARY is defined.
Unfortunately this patch doesn't help clean up the macro mess that we use to
configure for different ABI libraries.
llvm-svn: 290849
JF Bastien