Auto merge of #32080 - eddyb:transcendent, r=nikomatsakis

Refactor call & function handling in trans, enable MIR bootstrap.

Non-Rust and Rust ABIs were combined into a common codepath, which means:
* The ugly `__rust_abi` "clown shoes" shim for C->Rust FFI is gone, fixes #10116.
* Methods, *including virtual ones* support non-Rust ABIs, closes #30235.
* Non-Rust ABIs also pass fat pointers in two arguments; the result should be identical.
* Zero-sized types are never passed as arguments; again, behavior shouldn't change.

Additionally, MIR support for calling intrinsics (through old trans) was implemented.
Alongside assorted fixes, it enabled MIR to launch :rocket: and do a *complete* bootstrap.
To try it yourself, `./configure --enable-orbit` *or* `make RUSTFLAGS="-Z orbit"`.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index 5a2a043d6f1..e6f83498ab1 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -1008,6 +1008,7 @@ macro_rules! int_impl {
         /// ```
         #[stable(feature = "rust1", since = "1.0.0")]
         #[inline]
+        #[cfg_attr(not(stage0), rustc_no_mir)] // FIXME #29769 MIR overflow checking is TBD.
         pub fn pow(self, mut exp: u32) -> Self {
             let mut base = self;
             let mut acc = Self::one();
@@ -1049,6 +1050,7 @@ macro_rules! int_impl {
         /// ```
         #[stable(feature = "rust1", since = "1.0.0")]
         #[inline]
+        #[cfg_attr(not(stage0), rustc_no_mir)] // FIXME #29769 MIR overflow checking is TBD.
         pub fn abs(self) -> Self {
             if self.is_negative() {
                 // Note that the #[inline] above means that the overflow
@@ -2013,6 +2015,7 @@ macro_rules! uint_impl {
         /// ```
         #[stable(feature = "rust1", since = "1.0.0")]
         #[inline]
+        #[cfg_attr(not(stage0), rustc_no_mir)] // FIXME #29769 MIR overflow checking is TBD.
         pub fn pow(self, mut exp: u32) -> Self {
             let mut base = self;
             let mut acc = Self::one();