rust/compiler/rustc_target/src/spec/i686_unknown_linux_musl.rs
Simonas Kazlauskas 9b67cba4f6 Add support for leaf fn frame pointer elimination
This PR adds ability for the target specifications to specify frame
pointer emission type that's not just “always” or “whatever cg decides”.

In particular there's a new mode that allows omission of the frame
pointer for leaf functions (those that don't call any other functions).

We then set this new mode for Aarch64-based Apple targets.

Fixes #86196
2021-06-30 19:45:17 +03:00

36 lines
1.5 KiB
Rust

use crate::spec::{FramePointer, LinkerFlavor, StackProbeType, Target};
pub fn target() -> Target {
let mut base = super::linux_musl_base::opts();
base.cpu = "pentium4".to_string();
base.max_atomic_width = Some(64);
base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m32".to_string());
base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-Wl,-melf_i386".to_string());
// don't use probe-stack=inline-asm until rust#83139 and rust#84667 are resolved
base.stack_probes = StackProbeType::Call;
// The unwinder used by i686-unknown-linux-musl, the LLVM libunwind
// implementation, apparently relies on frame pointers existing... somehow.
// It's not clear to me why nor where this dependency is introduced, but the
// test suite does not pass with frame pointers eliminated and it passes
// with frame pointers present.
//
// If you think that this is no longer necessary, then please feel free to
// ignore! If it still passes the test suite and the bots then sounds good
// to me.
//
// This may or may not be related to this bug:
// https://llvm.org/bugs/show_bug.cgi?id=30879
base.frame_pointer = FramePointer::Always;
Target {
llvm_target: "i686-unknown-linux-musl".to_string(),
pointer_width: 32,
data_layout: "e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-\
f64:32:64-f80:32-n8:16:32-S128"
.to_string(),
arch: "x86".to_string(),
options: base,
}
}