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Refactor calling convention settings. (#304)

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Add a calling-convention setting to the `Flags` used as part of the
`TargetIsa`. This allows Cretonne code that generates calls to use the
correct convention, such as when emitting libcalls during legalization
or when the wasm frontend is decoding functions. This setting can be
overridden per-function.

This also adds "fast", "cold", and "fastcall" conventions, with "fast"
as the new default. Note that "fast" and "cold" are not intended to be
ABI-compatible across Cretonne versions.

This will also ensure Windows users will get an `unimplemented!` rather
than silent calling-convention mismatches, which reflects the fact that
Windows calling conventions are not yet implemented.

This also renames SpiderWASM, which isn't camel-case, to Baldrdash,
which is, and which is also a more relevant name.
This commit is contained in:
Dan Gohman
2018-04-22 21:35:18 -07:00
committed by GitHub
parent 8a9e4b9cff
commit c5b15c2396
38 changed files with 226 additions and 161 deletions
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65
lib/codegen/src/ir/extfunc.rs
View File

@@ -7,6 +7,7 @@
use ir::{ArgumentLoc, ExternalName, SigRef, Type};
use isa::{RegInfo, RegUnit};
use settings::CallConv;
use std::cmp;
use std::fmt;
use std::str::FromStr;
@@ -342,47 +343,6 @@ impl fmt::Display for ExtFuncData {
}
}
/// A Calling convention.
///
/// A function's calling convention determines exactly how arguments and return values are passed,
/// and how stack frames are managed. Since all of these details depend on both the instruction set
/// architecture and possibly the operating system, a function's calling convention is only fully
/// determined by a `(TargetIsa, CallConv)` tuple.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub enum CallConv {
/// The System V-style calling convention.
///
/// This is the System V-style calling convention that a C compiler would
/// use on many platforms.
SystemV,
/// A JIT-compiled WebAssembly function in the SpiderMonkey VM.
SpiderWASM,
}
impl fmt::Display for CallConv {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
use self::CallConv::*;
f.write_str(match *self {
SystemV => "system_v",
SpiderWASM => "spiderwasm",
})
}
}
impl FromStr for CallConv {
type Err = ();
fn from_str(s: &str) -> Result<Self, Self::Err> {
use self::CallConv::*;
match s {
"system_v" => Ok(SystemV),
"spiderwasm" => Ok(SpiderWASM),
_ => Err(()),
}
}
}
#[cfg(test)]
mod tests {
use super::*;
@@ -418,23 +378,30 @@ mod tests {
#[test]
fn call_conv() {
for &cc in &[CallConv::SystemV, CallConv::SpiderWASM] {
for &cc in &[
CallConv::Fast,
CallConv::Cold,
CallConv::SystemV,
CallConv::Fastcall,
CallConv::Baldrdash,
]
{
assert_eq!(Ok(cc), cc.to_string().parse())
}
}
#[test]
fn signatures() {
let mut sig = Signature::new(CallConv::SpiderWASM);
assert_eq!(sig.to_string(), "() spiderwasm");
let mut sig = Signature::new(CallConv::Baldrdash);
assert_eq!(sig.to_string(), "() baldrdash");
sig.params.push(AbiParam::new(I32));
assert_eq!(sig.to_string(), "(i32) spiderwasm");
assert_eq!(sig.to_string(), "(i32) baldrdash");
sig.returns.push(AbiParam::new(F32));
assert_eq!(sig.to_string(), "(i32) -> f32 spiderwasm");
assert_eq!(sig.to_string(), "(i32) -> f32 baldrdash");
sig.params.push(AbiParam::new(I32.by(4).unwrap()));
assert_eq!(sig.to_string(), "(i32, i32x4) -> f32 spiderwasm");
assert_eq!(sig.to_string(), "(i32, i32x4) -> f32 baldrdash");
sig.returns.push(AbiParam::new(B8));
assert_eq!(sig.to_string(), "(i32, i32x4) -> f32, b8 spiderwasm");
assert_eq!(sig.to_string(), "(i32, i32x4) -> f32, b8 baldrdash");
// Test the offset computation algorithm.
assert_eq!(sig.argument_bytes, None);
@@ -450,7 +417,7 @@ mod tests {
// Writing ABI-annotated signatures.
assert_eq!(
sig.to_string(),
"(i32 [24], i32x4 [8]) -> f32, b8 spiderwasm"
"(i32 [24], i32x4 [8]) -> f32, b8 baldrdash"
);
}
}