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
to reflect the new license. These used slightly different spellings that
defeated my regular expressions.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351648
The initial buildbot run found a few missing bits in the initial XFAIL list
for the no-exceptions libc++ variant. These discrepancies are as follows:
[1] Following two tests need XFAILs on the no-exceptions library variant.
My local runs had these two disabled for other reasons (unsupported):
- localization/locales/locale/locale.cons/char_pointer.pass.cpp
- numerics/complex.number/complex.ops/complex_divide_complex.pass.cpp
[2] These three does not need XFAILs, they were failing on my local runs for
other reasons:
- depr/depr.c.headers/uchar_h.pass.cpp
- input.output/iostreams.base/ios/basic.ios.members/copyfmt.pass.cpp
- .../category.collate/locale.collate.byname/transform.pass.cpp
(these are failing on my box for the default build as well)
The current patch fixes both the cases above. Additionally, I've run the
following scan to make sure I've covered all the cases:
> grep ' catch \| try \| throw ' -R . | perl -pe 's|(.*?):.*|\1|' | sort | \
uniq > 1.txt
> grep 'libcpp-no-exceptions' -R . | perl -pe 's|(.*?):.*|\1|' | sort | \
uniq > 2.txt
> diff 1.txt 2.txt
This showed up a few extra interesting cases:
[3] These two tests do not use try/catch/throw statements, but they fail at
runtime. Need to be investigated, I've left the XFAILs in.
- std/thread/futures/futures.shared_future/dtor.pass.cpp
- std/thread/futures/futures.unique_future/dtor.pass.cpp
[4] These tests use a macro named TEST_HAS_NO_EXCEPTIONS to conditionally
exclude try/catch/throw statements when running without exceptions. I'm not
entirely sure why this was needed (AFAIK, we didn't have a no-exceptions
library build before). The macro's defintion is quite similar to that of
_LIBCPP_NO_EXCEPTIONS. I will investigate if this can be reused for my test
fixes or if it should be replaced with _LIBCPP_NO_EXCEPTIONS.
- std/experimental/any/*
Change-Id: I9ad1e0edd78f305406eaa0ab148b1ab693f7e26a
llvm-svn: 252870
Fixes a small omission in libcxx that prevents libcxx being built when
-DLIBCXX_ENABLE_EXCEPTIONS=0 is specified.
This patch adds XFAILS to all those tests that are currently failing
on the new -fno-exceptions library variant. Follow-up patches will
update the tests (progressively) to cope with the new library variant.
Change-Id: I4b801bd8d8e4fe7193df9e55f39f1f393a8ba81a
llvm-svn: 252598
Marshall Clow