cranelift_codegen/isa/
call_conv.rs

1use crate::settings::{self, LibcallCallConv};
2use core::fmt;
3use core::str;
4use target_lexicon::{CallingConvention, Triple};
5
6#[cfg(feature = "enable-serde")]
7use serde_derive::{Deserialize, Serialize};
8
9/// Calling convention identifiers.
10#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
11#[cfg_attr(feature = "enable-serde", derive(Serialize, Deserialize))]
12pub enum CallConv {
13    /// Best performance, not ABI-stable.
14    Fast,
15    /// Smallest caller code size, not ABI-stable.
16    Cold,
17    /// Supports tail calls, not ABI-stable.
18    //
19    // Currently, this is basically sys-v except that callees pop stack
20    // arguments, rather than callers. Expected to change even more in the
21    // future, however!
22    Tail,
23    /// System V-style convention used on many platforms.
24    SystemV,
25    /// Windows "fastcall" convention, also used for x64 and ARM.
26    WindowsFastcall,
27    /// Mac aarch64 calling convention, which is a tweaked aarch64 ABI.
28    AppleAarch64,
29    /// Specialized convention for the probestack function.
30    Probestack,
31    /// The winch calling convention, not ABI-stable.
32    ///
33    /// The main difference to SystemV is that the winch calling convention
34    /// defines no callee-save registers, and restricts the number of return
35    /// registers to one integer, and one floating point.
36    Winch,
37}
38
39impl CallConv {
40    /// Return the default calling convention for the given target triple.
41    pub fn triple_default(triple: &Triple) -> Self {
42        match triple.default_calling_convention() {
43            // Default to System V for unknown targets because most everything
44            // uses System V.
45            Ok(CallingConvention::SystemV) | Err(()) => Self::SystemV,
46            Ok(CallingConvention::AppleAarch64) => Self::AppleAarch64,
47            Ok(CallingConvention::WindowsFastcall) => Self::WindowsFastcall,
48            Ok(unimp) => unimplemented!("calling convention: {:?}", unimp),
49        }
50    }
51
52    /// Returns the calling convention used for libcalls according to the current flags.
53    pub fn for_libcall(flags: &settings::Flags, default_call_conv: CallConv) -> Self {
54        match flags.libcall_call_conv() {
55            LibcallCallConv::IsaDefault => default_call_conv,
56            LibcallCallConv::Fast => Self::Fast,
57            LibcallCallConv::Cold => Self::Cold,
58            LibcallCallConv::SystemV => Self::SystemV,
59            LibcallCallConv::WindowsFastcall => Self::WindowsFastcall,
60            LibcallCallConv::AppleAarch64 => Self::AppleAarch64,
61            LibcallCallConv::Probestack => Self::Probestack,
62        }
63    }
64
65    /// Does this calling convention support tail calls?
66    pub fn supports_tail_calls(&self) -> bool {
67        match self {
68            CallConv::Tail => true,
69            _ => false,
70        }
71    }
72}
73
74impl fmt::Display for CallConv {
75    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
76        f.write_str(match *self {
77            Self::Fast => "fast",
78            Self::Cold => "cold",
79            Self::Tail => "tail",
80            Self::SystemV => "system_v",
81            Self::WindowsFastcall => "windows_fastcall",
82            Self::AppleAarch64 => "apple_aarch64",
83            Self::Probestack => "probestack",
84            Self::Winch => "winch",
85        })
86    }
87}
88
89impl str::FromStr for CallConv {
90    type Err = ();
91    fn from_str(s: &str) -> Result<Self, Self::Err> {
92        match s {
93            "fast" => Ok(Self::Fast),
94            "cold" => Ok(Self::Cold),
95            "tail" => Ok(Self::Tail),
96            "system_v" => Ok(Self::SystemV),
97            "windows_fastcall" => Ok(Self::WindowsFastcall),
98            "apple_aarch64" => Ok(Self::AppleAarch64),
99            "probestack" => Ok(Self::Probestack),
100            "winch" => Ok(Self::Winch),
101            _ => Err(()),
102        }
103    }
104}
cranelift_codegen/isa/call_conv.rs

cranelift_codegen/isa/
call_conv.rs
