Here using `"C"` the compiler will use `"aapcs"` or `"aapcs-vfp"`
depending on target configuration.
Of course this translates in a call to `__aeabi_fdiv` / `__aeabi_fmul`
on non-HF targets.
On `eabi` targets with +vfpv2/vfpv3 LLVM generate:
vmov s0, r1
vmov s2, r0
vdiv.f32 s0, s2, s0
vmov r0, s0
bx lr
On `eabihf` targets with +vfpv3-d16/d32/f32 +fp-only-sp LLVM generate:
vdiv.f32 s0, s0, s1
bx lr
That's exactly what We need for [div/mul][s/d]f3vfp.S
* I believe `__gtdf2` erroneously used `f32` instead of `f64`
* Most of these needed `#[arm_aeabi_alias]` to ensure they're correctly called
through the alias
* Some existing aliases were corrected with the right names
First of all aeabi_cdcmp and aeabi_cfcmp are never called LLVM.
Second are little-endian only, so build fail on big-endian targets.
Temporally workaround: exclude these files for big-endian targets.
Note that this changes semantics:
pub extern "C" fn __eqsf2(a: f32, b: f32) -> bool {
cmp(a, b).to_le_abi() != 0
}
is not the same as
pub extern "C" fn __eqsf2(a: f32, b: f32) -> i32 {
cmp(a, b).to_le_abi()
}
However, compiler-rt does the latter, so this is actually
an improvement.
E.g. take a look at the assembly output for:
pub fn comparesf2(a: f32, b: f32) -> bool { a > b }
pub fn comparedf2(a: f64, b: f64) -> bool { a > b }
which will include calls to __gtsf2 and __gtdf2.
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.
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.
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
