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// Copyright 2013 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.
use driver::session::{OsWin32, OsMacos};
use lib::llvm::*;
use super::cabi::*;
use super::common::*;
use super::machine::*;
use middle::trans::type_::Type;
pub fn compute_abi_info(ccx: &mut CrateContext,
atys: &[Type],
rty: Type,
ret_def: bool) -> FnType {
let mut arg_tys = ~[];
let mut attrs = ~[];
let ret_ty;
let sret;
if !ret_def {
ret_ty = LLVMType {
cast: false,
ty: Type::void(),
};
sret = false;
} else if rty.kind() == Struct {
// Returning a structure. Most often, this will use
// a hidden first argument. On some platforms, though,
// small structs are returned as integers.
//
// Some links:
// http://www.angelcode.com/dev/callconv/callconv.html
// Clang's ABI handling is in lib/CodeGen/TargetInfo.cpp
enum Strategy { RetValue(Type), RetPointer }
let strategy = match ccx.sess.targ_cfg.os {
OsWin32 | OsMacos => {
match llsize_of_alloc(ccx, rty) {
1 => RetValue(Type::i8()),
2 => RetValue(Type::i16()),
4 => RetValue(Type::i32()),
8 => RetValue(Type::i64()),
_ => RetPointer
}
}
_ => {
RetPointer
}
};
match strategy {
RetValue(t) => {
ret_ty = LLVMType {
cast: true,
ty: t
};
sret = false;
}
RetPointer => {
arg_tys.push(LLVMType {
cast: false,
ty: rty.ptr_to()
});
attrs.push(Some(StructRetAttribute));
ret_ty = LLVMType {
cast: false,
ty: Type::void(),
};
sret = true;
}
}
} else {
ret_ty = LLVMType {
cast: false,
ty: rty
};
sret = false;
}
for &a in atys.iter() {
arg_tys.push(LLVMType { cast: false, ty: a });
attrs.push(None);
}
return FnType {
arg_tys: arg_tys,
ret_ty: ret_ty,
attrs: attrs,
sret: sret
};
}
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