Remove mulsf3.c and muldf3.c from compiler-rt.
mulsf3 and muldf3 have Rust implementations since 8970485. This PR removes the C implementations to avoid conflicts.
Without this I wasn't able to compile the crate with the "c" feature enabled, the errors being
`multiple definition of '__muldf3'` and `multiple definition of '__mulsf3'`.
Use the "volatile" option and the "memory" clobber on inline asm that does
things like return directly, to reduce the chances of compilers rearranging
the code.
This commit prepares the build script for a wasm32 target that doesn't use
Emcripten, notably forcing the `mem` feature to get activated and forcibly
ignoring the `c` feature, even if activated, for the wasm32 target.
drop binfmt_misc dependency
Instead use the Cargo runner feature. The binfmt_misc approach requires running a privileged
container for setup. Not all docker setups support privileged containers so the test suite should be
more accessible with this change as no privileged container is needed.
r? @alexcrichton
Instead use the Cargo runner feature. The binfmt_misc approach requires running a privileged
container for setup. Not all docker setups support privileged containers so the test suite should be
more accessible with this change as no privileged container is needed.
Add atomic support for pre-ARMv6 on Linux
This uses the [kernel user helpers](https://www.kernel.org/doc/Documentation/arm/kernel_user_helpers.txt) which are available starting from kernel 2.6.15. Since Rust currently requires 2.6.18 at a minimum, this should be fine in practice. I did not include support for 64-bit atomics since that functionality is only available in kernel 3.1.
This PR allows Rust to work on older ARM versions such as ARMv4 and ARMv5 with the full libstd.
Implement x86 chkstk in "rust"
cc #183
Basically the same as the x86_64 ones, except `__alloca` doesn't need to fix the parameter register. I've manually verified that the disassembly is the same, and that these work in a compiled rust program.
The second commit disables compiling probestack functions for `feature = mangled-names`. They aren't needed during testing because they aren't comparison tested and the unmangled versions are the ones that actually get used.
r? @alexcrichton
Update rustbuild commentary
r? @nikomatsakis
This is the reason that https://github.com/rust-lang/rust/pull/44509 doesn't work - the `rustbuild` feature _is_ actually used, it was just incorrectly documented here and I missed it.
