Add support for x86-interrupt calling convention

Tracking issue: https://github.com/rust-lang/rust/issues/40180

This calling convention can be used for definining interrupt handlers on
32-bit and 64-bit x86 targets. The compiler then uses `iret` instead of
`ret` for returning and ensures that all registers are restored to their
original values.

Usage:

```
extern "x86-interrupt" fn handler(stack_frame: &ExceptionStackFrame) {…}
```

for interrupts and exceptions without error code and

```
extern "x86-interrupt" fn page_fault_handler(stack_frame: &ExceptionStackFrame,
                                             error_code: u64) {…}
```

for exceptions that push an error code (e.g., page faults or general
protection faults). The programmer must ensure that the correct version
is used for each interrupt.

For more details see the [LLVM PR][1] and the corresponding [proposal][2].

[1]: https://reviews.llvm.org/D15567
[2]: http://lists.llvm.org/pipermail/cfe-dev/2015-September/045171.html

1 files changed, 28 insertions, 0 deletions

diff --git a/src/test/codegen/abi-x86-interrupt.rs b/src/test/codegen/abi-x86-interrupt.rs
new file mode 100644
index 00000000000..838cd4bf6d7
--- /dev/null
+++ b/src/test/codegen/abi-x86-interrupt.rs
@@ -0,0 +1,28 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Checks if the correct annotation for the x86-interrupt ABI is passed to
+// llvm. Also checks that the abi_x86_interrupt feature gate allows usage
+// of the x86-interrupt abi.
+
+// ignore-arm
+// ignore-aarch64
+// min-llvm-version 3.8
+
+// compile-flags: -C no-prepopulate-passes
+
+#![crate_type = "lib"]
+#![feature(abi_x86_interrupt)]
+
+// CHECK: define x86_intrcc i64 @has_x86_interrupt_abi
+#[no_mangle]
+pub extern "x86-interrupt" fn has_x86_interrupt_abi(a: i64) -> i64 {
+    a * 2
+}