This commit changes all MSVC rustc binaries to be compiled with
`-C target-feature=+crt-static` to link statically against the MSVCRT instead of
dynamically (as it does today). This also necessitates compiling LLVM in a
different fashion, ensuring it's compiled with `/MT` instead of `/MD`.
cc #37406
This commit switches the default build system for Rust from the makefiles to
rustbuild. The rustbuild build system has been in development for almost a year
now and has become quite mature over time. This commit is an implementation of
the proposal on [internals] which slates deletion of the makefiles on
2016-01-02.
[internals]: https://internals.rust-lang.org/t/proposal-for-promoting-rustbuild-to-official-status/4368
This commit also updates various documentation in `README.md`,
`CONTRIBUTING.md`, `src/bootstrap/README.md`, and throughout the source code of
rustbuild itself.
Closes#37858
We hope to move to AppVeyor in the near future off of Buildbot + EC2. This adds
an `appveyor.yml` configuration file which is ready to run builds on the auto
branch. This is also accompanied with a few minor fixes to the build system and
such to accomodate AppVeyor.
The intention is that we're not switching over to AppVeyor entirely just yet,
but rather we'll watch the builds for a week or so. If everything checks out
then we'll start gating on AppVeyor instead of Buildbot!
Point llvm @bitshifter branch until PR accepted
Use today's date for LLVM auto clean trigger
Update LLVM submodule to point at rust-lang fork.
Handle case when target is set
Currently the compiler has two relatively critical bugs in the implementation of
MSVC unwinding:
* #33112 - faults like segfaults and illegal instructions will run destructors
in Rust, meaning we keep running code after a super-fatal exception
has happened.
* #33116 - When compiling with LTO plus `-Z no-landing-pads` (or `-C
panic=abort` with the previous commit) LLVM won't remove all `invoke`
instructions, meaning that some landing pads stick around and
cleanups may be run due to the previous bug.
These both stem from the flavor of "personality function" that Rust uses for
unwinding on MSVC. On 32-bit this is `_except_handler3` and on 64-bit this is
`__C_specific_handler`, but they both essentially are the "most generic"
personality functions for catching exceptions and running cleanups. That is,
thse two personalities will run cleanups for all exceptions unconditionally, so
when we use them we run cleanups for **all SEH exceptions** (include things like
segfaults).
Note that this also explains why LLVM won't optimize away `invoke` instructions.
These functions can legitimately still unwind (the `nounwind` attribute only
seems to apply to "C++ exception-like unwining"). Also note that the standard
library only *catches* Rust exceptions, not others like segfaults and illegal
instructions.
LLVM has support for another personality, `__CxxFrameHandler3`, which does not
run cleanups for general exceptions, only C++ exceptions thrown by
`_CxxThrowException`. This essentially ideally matches our use case, so this
commit moves us over to using this well-known personality function as well as
exception-throwing function.
This doesn't *seem* to pull in any extra runtime dependencies just yet, but if
it does we can perhaps try to work out how to implement more of it in Rust
rather than relying on MSVCRT runtime bits.
More details about how this is actually implemented can be found in the changes
itself, but this...
Closes#33112Closes#33116
This commit fixes our support for cross compiling a compiler to run on FreeBSD.
Over the weekend I managed to get a cross compiler from Linux to FreeBSD [1]
which I hope to soon use to start producing FreeBSD nightly compilers. With the
`make dist` support added in #32237 we should be able to produce standard
rustc/rust-std packages for FreeBSD through a new slave with this cross compiler.
Currently, however, we don't "Just Work" when cross compiling FreeBSD and a
number of changes were required (part of this PR). They include:
* A few build fixes were needed in LLVM. Our own branch has been rebased on the
actual 3.8 release and I applied one extra commit [2] which contains two fixes:
1. The LLVM CMake build system passes the `-Wl,-z,defs` flag on many
platforms, but *not* when `CMAKE_SYSTEM_NAME` is "FreeBSD". Unfortunately
this doesn't take into account when we're cross compiling, and as predicted
the build will fail if `-Wl,-z,defs` is passed (see [3] for more info). To
fix this we test `TARGET_TRIPLE` instead of the `CMAKE_SYSTEM_NAME` which
is what we're compiling for which fixes the problem.
2. The `PATH_MAX` constant is apparently defined in a different location than
many other Unix systems, so a file which required this just needed some
help to keep compiling.
* Support for compiling compiler-rt with CMake has been added to rustbuild. It
looks like it just emulates Linux in what it compiles as it didn't seem to
naturally produce anything else... At least the architecture is right, so
seems good for now at least!
[1]: https://github.com/alexcrichton/port-of-rust/blob/master/prebuilt/freebsd/Dockerfile
[2]: https://github.com/rust-lang/llvm/commit/be89e4b5
[3]: https://bugs.webkit.org/show_bug.cgi?id=138420
This commit rebases our LLVM submodule on the most recent tip of the
`release_38` branch of LLVM. There's been a few fixes and this notably fixes the
assertion error in #31702.
This brings some routine upgrades to the bundled LLVM that we're using, the most
notable of which is a bug fix to the way we handle range asserts when loading
the discriminant of an enum. This fix ended up being very similar to f9d4149c
where we basically can't have a range assert when loading a discriminant due to
filling drop, and appropriate flags were added to communicate this to
`trans::adt`.
There's a number of goodies in this LLVM update:
* This contains a fix for https://llvm.org/bugs/show_bug.cgi?id=23957
which should help us bootstrap farther on 32-bit MSVC targets.
* There is better support for writing multiple flavors of archives, allowing us
to use the built-in LLVM support instead of the system `ar` on all current
platforms of the compiler.
* A number of other minor bug fixes and performance improvements to unblock
various other pieces of work.
This commit updates the LLVM submodule in use to the current HEAD of the LLVM
repository. This is primarily being done to start picking up unwinding support
for MSVC, which is currently unimplemented in the revision of LLVM we are using.
Along the way a few changes had to be made:
* As usual, lots of C++ debuginfo bindings in LLVM changed, so there were some
significant changes to our RustWrapper.cpp
* As usual, some pass management changed in LLVM, so clang was re-scrutinized to
ensure that we're doing the same thing as clang.
* Some optimization options are now passed directly into the
`PassManagerBuilder` instead of through CLI switches to LLVM.
* The `NoFramePointerElim` option was removed from LLVM, favoring instead the
`no-frame-pointer-elim` function attribute instead.
Additionally, LLVM has picked up some new optimizations which required fixing an
existing soundness hole in the IR we generate. It appears that the current LLVM
we use does not expose this hole. When an enum is moved, the previous slot in
memory is overwritten with a bit pattern corresponding to "dropped". When the
drop glue for this slot is run, however, the switch on the discriminant can
often start executing the `unreachable` block of the switch due to the
discriminant now being outside the normal range. This was patched over locally
for now by having the `unreachable` block just change to a `ret void`.
