85 lines
2.6 KiB
Rust
85 lines
2.6 KiB
Rust
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use syntax::abi::{OsWin32, OsMacos};
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use lib::llvm::*;
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use super::cabi::*;
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use super::common::*;
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use super::machine::*;
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use middle::trans::type_::Type;
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pub fn compute_abi_info(ccx: &CrateContext,
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atys: &[Type],
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rty: Type,
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ret_def: bool) -> FnType {
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let mut arg_tys = Vec::new();
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let ret_ty;
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if !ret_def {
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ret_ty = ArgType::direct(Type::void(ccx), None, None, None);
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} else if rty.kind() == Struct {
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// Returning a structure. Most often, this will use
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// a hidden first argument. On some platforms, though,
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// small structs are returned as integers.
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//
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// Some links:
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// http://www.angelcode.com/dev/callconv/callconv.html
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// Clang's ABI handling is in lib/CodeGen/TargetInfo.cpp
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enum Strategy { RetValue(Type), RetPointer }
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let strategy = match ccx.sess().targ_cfg.os {
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OsWin32 | OsMacos => {
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match llsize_of_alloc(ccx, rty) {
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1 => RetValue(Type::i8(ccx)),
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2 => RetValue(Type::i16(ccx)),
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4 => RetValue(Type::i32(ccx)),
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8 => RetValue(Type::i64(ccx)),
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_ => RetPointer
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}
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}
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_ => {
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RetPointer
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}
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};
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match strategy {
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RetValue(t) => {
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ret_ty = ArgType::direct(rty, Some(t), None, None);
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}
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RetPointer => {
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ret_ty = ArgType::indirect(rty, Some(StructRetAttribute));
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}
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}
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} else {
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ret_ty = ArgType::direct(rty, None, None, None);
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}
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for &t in atys.iter() {
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let ty = match t.kind() {
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Struct => {
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let size = llsize_of_alloc(ccx, t);
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if size == 0 {
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ArgType::ignore(t)
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} else {
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ArgType::indirect(t, Some(ByValAttribute))
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}
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}
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_ => ArgType::direct(t, None, None, None),
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};
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arg_tys.push(ty);
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}
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return FnType {
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arg_tys: arg_tys,
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ret_ty: ret_ty,
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};
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}
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