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1 | // Copyright 2013 The Rust Project Developers. See the COPYRIGHT |
2 | // file at the top-level directory of this distribution and at | |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
10 | ||
83c7162d XL |
11 | use abi::call::{ArgAttribute, FnType, PassMode, Reg, RegKind}; |
12 | use abi::{self, HasDataLayout, LayoutOf, TyLayout, TyLayoutMethods}; | |
13 | use spec::HasTargetSpec; | |
ea8adc8c | 14 | |
32a655c1 SL |
15 | #[derive(PartialEq)] |
16 | pub enum Flavor { | |
17 | General, | |
18 | Fastcall | |
19 | } | |
20 | ||
83c7162d XL |
21 | fn is_single_fp_element<'a, Ty, C>(cx: C, layout: TyLayout<'a, Ty>) -> bool |
22 | where Ty: TyLayoutMethods<'a, C> + Copy, | |
23 | C: LayoutOf<Ty = Ty, TyLayout = TyLayout<'a, Ty>> + HasDataLayout | |
24 | { | |
ff7c6d11 | 25 | match layout.abi { |
94b46f34 | 26 | abi::Abi::Scalar(ref scalar) => scalar.value.is_float(), |
83c7162d | 27 | abi::Abi::Aggregate { .. } => { |
ff7c6d11 | 28 | if layout.fields.count() == 1 && layout.fields.offset(0).bytes() == 0 { |
2c00a5a8 | 29 | is_single_fp_element(cx, layout.field(cx, 0)) |
ea8adc8c XL |
30 | } else { |
31 | false | |
32 | } | |
33 | } | |
34 | _ => false | |
35 | } | |
36 | } | |
37 | ||
83c7162d XL |
38 | pub fn compute_abi_info<'a, Ty, C>(cx: C, fty: &mut FnType<'a, Ty>, flavor: Flavor) |
39 | where Ty: TyLayoutMethods<'a, C> + Copy, | |
40 | C: LayoutOf<Ty = Ty, TyLayout = TyLayout<'a, Ty>> + HasDataLayout + HasTargetSpec | |
41 | { | |
54a0048b | 42 | if !fty.ret.is_ignore() { |
cc61c64b | 43 | if fty.ret.layout.is_aggregate() { |
54a0048b SL |
44 | // Returning a structure. Most often, this will use |
45 | // a hidden first argument. On some platforms, though, | |
46 | // small structs are returned as integers. | |
47 | // | |
48 | // Some links: | |
49 | // http://www.angelcode.com/dev/callconv/callconv.html | |
50 | // Clang's ABI handling is in lib/CodeGen/TargetInfo.cpp | |
83c7162d | 51 | let t = cx.target_spec(); |
0531ce1d | 52 | if t.options.abi_return_struct_as_int { |
ea8adc8c XL |
53 | // According to Clang, everyone but MSVC returns single-element |
54 | // float aggregates directly in a floating-point register. | |
2c00a5a8 | 55 | if !t.options.is_like_msvc && is_single_fp_element(cx, fty.ret.layout) { |
ff7c6d11 XL |
56 | match fty.ret.layout.size.bytes() { |
57 | 4 => fty.ret.cast_to(Reg::f32()), | |
58 | 8 => fty.ret.cast_to(Reg::f64()), | |
59 | _ => fty.ret.make_indirect() | |
ea8adc8c XL |
60 | } |
61 | } else { | |
ff7c6d11 XL |
62 | match fty.ret.layout.size.bytes() { |
63 | 1 => fty.ret.cast_to(Reg::i8()), | |
64 | 2 => fty.ret.cast_to(Reg::i16()), | |
65 | 4 => fty.ret.cast_to(Reg::i32()), | |
66 | 8 => fty.ret.cast_to(Reg::i64()), | |
67 | _ => fty.ret.make_indirect() | |
ea8adc8c | 68 | } |
54a0048b SL |
69 | } |
70 | } else { | |
ff7c6d11 | 71 | fty.ret.make_indirect(); |
54a0048b SL |
72 | } |
73 | } else { | |
74 | fty.ret.extend_integer_width_to(32); | |
75 | } | |
76 | } | |
77 | ||
78 | for arg in &mut fty.args { | |
79 | if arg.is_ignore() { continue; } | |
cc61c64b | 80 | if arg.layout.is_aggregate() { |
ff7c6d11 | 81 | arg.make_indirect_byval(); |
54a0048b SL |
82 | } else { |
83 | arg.extend_integer_width_to(32); | |
84 | } | |
85 | } | |
32a655c1 SL |
86 | |
87 | if flavor == Flavor::Fastcall { | |
88 | // Mark arguments as InReg like clang does it, | |
89 | // so our fastcall is compatible with C/C++ fastcall. | |
90 | ||
91 | // Clang reference: lib/CodeGen/TargetInfo.cpp | |
92 | // See X86_32ABIInfo::shouldPrimitiveUseInReg(), X86_32ABIInfo::updateFreeRegs() | |
93 | ||
94 | // IsSoftFloatABI is only set to true on ARM platforms, | |
95 | // which in turn can't be x86? | |
96 | ||
97 | let mut free_regs = 2; | |
98 | ||
99 | for arg in &mut fty.args { | |
ff7c6d11 XL |
100 | let attrs = match arg.mode { |
101 | PassMode::Ignore | | |
102 | PassMode::Indirect(_) => continue, | |
103 | PassMode::Direct(ref mut attrs) => attrs, | |
104 | PassMode::Pair(..) | | |
105 | PassMode::Cast(_) => { | |
83c7162d | 106 | unreachable!("x86 shouldn't be passing arguments by {:?}", arg.mode) |
ff7c6d11 XL |
107 | } |
108 | }; | |
32a655c1 | 109 | |
cc61c64b | 110 | // At this point we know this must be a primitive of sorts. |
2c00a5a8 | 111 | let unit = arg.layout.homogeneous_aggregate(cx).unwrap(); |
ff7c6d11 | 112 | assert_eq!(unit.size, arg.layout.size); |
cc61c64b | 113 | if unit.kind == RegKind::Float { |
32a655c1 SL |
114 | continue; |
115 | } | |
116 | ||
ff7c6d11 | 117 | let size_in_regs = (arg.layout.size.bits() + 31) / 32; |
32a655c1 SL |
118 | |
119 | if size_in_regs == 0 { | |
120 | continue; | |
121 | } | |
122 | ||
123 | if size_in_regs > free_regs { | |
124 | break; | |
125 | } | |
126 | ||
127 | free_regs -= size_in_regs; | |
128 | ||
ff7c6d11 XL |
129 | if arg.layout.size.bits() <= 32 && unit.kind == RegKind::Integer { |
130 | attrs.set(ArgAttribute::InReg); | |
32a655c1 SL |
131 | } |
132 | ||
133 | if free_regs == 0 { | |
134 | break; | |
135 | } | |
136 | } | |
137 | } | |
54a0048b | 138 | } |