| // Copyright 2014-2016 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. |
| |
| // FIXME: |
| // Alignment of 128 bit types is not currently handled, this will |
| // need to be fixed when PowerPC vector support is added. |
| |
| use abi::{FnType, ArgType, LayoutExt, Reg, RegKind, Uniform}; |
| use context::CrateContext; |
| use rustc::ty::layout; |
| |
| #[derive(Debug, Clone, Copy, PartialEq)] |
| enum ABI { |
| ELFv1, // original ABI used for powerpc64 (big-endian) |
| ELFv2, // newer ABI used for powerpc64le |
| } |
| use self::ABI::*; |
| |
| fn is_homogeneous_aggregate<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, |
| arg: &mut ArgType<'tcx>, |
| abi: ABI) |
| -> Option<Uniform> { |
| arg.layout.homogeneous_aggregate(ccx).and_then(|unit| { |
| // ELFv1 only passes one-member aggregates transparently. |
| // ELFv2 passes up to eight uniquely addressable members. |
| if (abi == ELFv1 && arg.layout.size > unit.size) |
| || arg.layout.size > unit.size.checked_mul(8, ccx).unwrap() { |
| return None; |
| } |
| |
| let valid_unit = match unit.kind { |
| RegKind::Integer => false, |
| RegKind::Float => true, |
| RegKind::Vector => arg.layout.size.bits() == 128 |
| }; |
| |
| if valid_unit { |
| Some(Uniform { |
| unit, |
| total: arg.layout.size |
| }) |
| } else { |
| None |
| } |
| }) |
| } |
| |
| fn classify_ret_ty<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, ret: &mut ArgType<'tcx>, abi: ABI) { |
| if !ret.layout.is_aggregate() { |
| ret.extend_integer_width_to(64); |
| return; |
| } |
| |
| // The ELFv1 ABI doesn't return aggregates in registers |
| if abi == ELFv1 { |
| ret.make_indirect(); |
| return; |
| } |
| |
| if let Some(uniform) = is_homogeneous_aggregate(ccx, ret, abi) { |
| ret.cast_to(uniform); |
| return; |
| } |
| |
| let size = ret.layout.size; |
| let bits = size.bits(); |
| if bits <= 128 { |
| let unit = if bits <= 8 { |
| Reg::i8() |
| } else if bits <= 16 { |
| Reg::i16() |
| } else if bits <= 32 { |
| Reg::i32() |
| } else { |
| Reg::i64() |
| }; |
| |
| ret.cast_to(Uniform { |
| unit, |
| total: size |
| }); |
| return; |
| } |
| |
| ret.make_indirect(); |
| } |
| |
| fn classify_arg_ty<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, arg: &mut ArgType<'tcx>, abi: ABI) { |
| if !arg.layout.is_aggregate() { |
| arg.extend_integer_width_to(64); |
| return; |
| } |
| |
| if let Some(uniform) = is_homogeneous_aggregate(ccx, arg, abi) { |
| arg.cast_to(uniform); |
| return; |
| } |
| |
| let size = arg.layout.size; |
| let (unit, total) = match abi { |
| ELFv1 => { |
| // In ELFv1, aggregates smaller than a doubleword should appear in |
| // the least-significant bits of the parameter doubleword. The rest |
| // should be padded at their tail to fill out multiple doublewords. |
| if size.bits() <= 64 { |
| (Reg { kind: RegKind::Integer, size }, size) |
| } else { |
| let align = layout::Align::from_bits(64, 64).unwrap(); |
| (Reg::i64(), size.abi_align(align)) |
| } |
| }, |
| ELFv2 => { |
| // In ELFv2, we can just cast directly. |
| (Reg::i64(), size) |
| }, |
| }; |
| |
| arg.cast_to(Uniform { |
| unit, |
| total |
| }); |
| } |
| |
| pub fn compute_abi_info<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>, fty: &mut FnType<'tcx>) { |
| let abi = match ccx.sess().target.target.target_endian.as_str() { |
| "big" => ELFv1, |
| "little" => ELFv2, |
| _ => unimplemented!(), |
| }; |
| |
| if !fty.ret.is_ignore() { |
| classify_ret_ty(ccx, &mut fty.ret, abi); |
| } |
| |
| for arg in &mut fty.args { |
| if arg.is_ignore() { continue; } |
| classify_arg_ty(ccx, arg, abi); |
| } |
| } |