rust/src/librustc_trans/trans/cabi_arm.rs

152 lines
4.1 KiB
Rust

// Copyright 2012-2013 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.
#![allow(non_upper_case_globals)]
use llvm;
use llvm::{Integer, Pointer, Float, Double, Struct, Array};
use llvm::{StructRetAttribute, ZExtAttribute};
use trans::cabi::{FnType, ArgType};
use trans::context::CrateContext;
use trans::type_::Type;
use std::cmp;
fn align_up_to(off: uint, a: uint) -> uint {
return (off + a - 1u) / a * a;
}
fn align(off: uint, ty: Type) -> uint {
let a = ty_align(ty);
return align_up_to(off, a);
}
fn ty_align(ty: Type) -> uint {
match ty.kind() {
Integer => {
unsafe {
((llvm::LLVMGetIntTypeWidth(ty.to_ref()) as uint) + 7) / 8
}
}
Pointer => 4,
Float => 4,
Double => 8,
Struct => {
if ty.is_packed() {
1
} else {
let str_tys = ty.field_types();
str_tys.iter().fold(1, |a, t| cmp::max(a, ty_align(*t)))
}
}
Array => {
let elt = ty.element_type();
ty_align(elt)
}
_ => panic!("ty_align: unhandled type")
}
}
fn ty_size(ty: Type) -> uint {
match ty.kind() {
Integer => {
unsafe {
((llvm::LLVMGetIntTypeWidth(ty.to_ref()) as uint) + 7) / 8
}
}
Pointer => 4,
Float => 4,
Double => 8,
Struct => {
if ty.is_packed() {
let str_tys = ty.field_types();
str_tys.iter().fold(0, |s, t| s + ty_size(*t))
} else {
let str_tys = ty.field_types();
let size = str_tys.iter().fold(0, |s, t| align(s, *t) + ty_size(*t));
align(size, ty)
}
}
Array => {
let len = ty.array_length();
let elt = ty.element_type();
let eltsz = ty_size(elt);
len * eltsz
}
_ => panic!("ty_size: unhandled type")
}
}
fn classify_ret_ty(ccx: &CrateContext, ty: Type) -> ArgType {
if is_reg_ty(ty) {
let attr = if ty == Type::i1(ccx) { Some(ZExtAttribute) } else { None };
return ArgType::direct(ty, None, None, attr);
}
let size = ty_size(ty);
if size <= 4 {
let llty = if size <= 1 {
Type::i8(ccx)
} else if size <= 2 {
Type::i16(ccx)
} else {
Type::i32(ccx)
};
return ArgType::direct(ty, Some(llty), None, None);
}
ArgType::indirect(ty, Some(StructRetAttribute))
}
fn classify_arg_ty(ccx: &CrateContext, ty: Type) -> ArgType {
if is_reg_ty(ty) {
let attr = if ty == Type::i1(ccx) { Some(ZExtAttribute) } else { None };
return ArgType::direct(ty, None, None, attr);
}
let align = ty_align(ty);
let size = ty_size(ty);
let llty = if align <= 4 {
Type::array(&Type::i32(ccx), ((size + 3) / 4) as u64)
} else {
Type::array(&Type::i64(ccx), ((size + 7) / 8) as u64)
};
ArgType::direct(ty, Some(llty), None, None)
}
fn is_reg_ty(ty: Type) -> bool {
match ty.kind() {
Integer
| Pointer
| Float
| Double => true,
_ => false
}
}
pub fn compute_abi_info(ccx: &CrateContext,
atys: &[Type],
rty: Type,
ret_def: bool) -> FnType {
let mut arg_tys = Vec::new();
for &aty in atys.iter() {
let ty = classify_arg_ty(ccx, aty);
arg_tys.push(ty);
}
let ret_ty = if ret_def {
classify_ret_ty(ccx, rty)
} else {
ArgType::direct(Type::void(ccx), None, None, None)
};
return FnType {
arg_tys: arg_tys,
ret_ty: ret_ty,
};
}