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// Copyright 2018 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 builder::Builder;
use rustc_codegen_ssa::mir::operand::OperandRef;
use rustc_codegen_ssa::traits::{BaseTypeMethods, BuilderMethods, ConstMethods, DerivedTypeMethods};
use rustc::ty::layout::{Align, HasDataLayout, HasTyCtxt, LayoutOf, Size};
use rustc::ty::Ty;
use type_::Type;
use type_of::LayoutLlvmExt;
use value::Value;
#[allow(dead_code)]
fn round_pointer_up_to_alignment(
bx: &mut Builder<'a, 'll, 'tcx>,
addr: &'ll Value,
align: Align,
ptr_ty: &'ll Type
) -> &'ll Value {
let mut ptr_as_int = bx.ptrtoint(addr, bx.cx().type_isize());
ptr_as_int = bx.add(ptr_as_int, bx.cx().const_i32(align.bytes() as i32 - 1));
ptr_as_int = bx.and(ptr_as_int, bx.cx().const_i32(-(align.bytes() as i32)));
bx.inttoptr(ptr_as_int, ptr_ty)
}
fn emit_direct_ptr_va_arg(
bx: &mut Builder<'a, 'll, 'tcx>,
list: OperandRef<'tcx, &'ll Value>,
llty: &'ll Type,
size: Size,
align: Align,
slot_size: Align,
allow_higher_align: bool
) -> (&'ll Value, Align) {
let va_list_ptr_ty = bx.cx().type_ptr_to(bx.cx.type_i8p());
let va_list_addr = if list.layout.llvm_type(bx.cx) != va_list_ptr_ty {
bx.bitcast(list.immediate(), va_list_ptr_ty)
} else {
list.immediate()
};
let ptr = bx.load(va_list_addr, bx.tcx().data_layout.pointer_align.abi);
let (addr, addr_align) = if allow_higher_align && align > slot_size {
(round_pointer_up_to_alignment(bx, ptr, align, bx.cx().type_i8p()), align)
} else {
(ptr, slot_size)
};
let aligned_size = size.align_to(slot_size).bytes() as i32;
let full_direct_size = bx.cx().const_i32(aligned_size);
let next = bx.inbounds_gep(addr, &[full_direct_size]);
bx.store(next, va_list_addr, bx.tcx().data_layout.pointer_align.abi);
if size.bytes() < slot_size.bytes() &&
&*bx.tcx().sess.target.target.target_endian == "big" {
let adjusted_size = bx.cx().const_i32((slot_size.bytes() - size.bytes()) as i32);
let adjusted = bx.inbounds_gep(addr, &[adjusted_size]);
(bx.bitcast(adjusted, bx.cx().type_ptr_to(llty)), addr_align)
} else {
(bx.bitcast(addr, bx.cx().type_ptr_to(llty)), addr_align)
}
}
fn emit_ptr_va_arg(
bx: &mut Builder<'a, 'll, 'tcx>,
list: OperandRef<'tcx, &'ll Value>,
target_ty: Ty<'tcx>,
indirect: bool,
slot_size: Align,
allow_higher_align: bool
) -> &'ll Value {
let layout = bx.cx.layout_of(target_ty);
let (llty, size, align) = if indirect {
(bx.cx.layout_of(bx.cx.tcx.mk_imm_ptr(target_ty)).llvm_type(bx.cx),
bx.cx.data_layout().pointer_size,
bx.cx.data_layout().pointer_align)
} else {
(layout.llvm_type(bx.cx),
layout.size,
layout.align)
};
let (addr, addr_align) = emit_direct_ptr_va_arg(bx, list, llty, size, align.abi,
slot_size, allow_higher_align);
if indirect {
let tmp_ret = bx.load(addr, addr_align);
bx.load(tmp_ret, align.abi)
} else {
bx.load(addr, addr_align)
}
}
pub(super) fn emit_va_arg(
bx: &mut Builder<'a, 'll, 'tcx>,
addr: OperandRef<'tcx, &'ll Value>,
target_ty: Ty<'tcx>,
) -> &'ll Value {
// Determine the va_arg implementation to use. The LLVM va_arg instruction
// is lacking in some instances, so we should only use it as a fallback.
let arch = &bx.cx.tcx.sess.target.target.arch;
match (&**arch,
bx.cx.tcx.sess.target.target.options.is_like_windows) {
("x86", true) => {
emit_ptr_va_arg(bx, addr, target_ty, false,
Align::from_bytes(4).unwrap(), false)
}
("x86_64", true) => {
let target_ty_size = bx.cx.size_of(target_ty).bytes();
let indirect = if target_ty_size > 8 || !target_ty_size.is_power_of_two() {
true
} else {
false
};
emit_ptr_va_arg(bx, addr, target_ty, indirect,
Align::from_bytes(8).unwrap(), false)
}
("x86", false) => {
emit_ptr_va_arg(bx, addr, target_ty, false,
Align::from_bytes(4).unwrap(), true)
}
_ => {
let va_list = if (bx.tcx().sess.target.target.arch == "aarch64" ||
bx.tcx().sess.target.target.arch == "x86_64" ||
bx.tcx().sess.target.target.arch == "powerpc") &&
!bx.tcx().sess.target.target.options.is_like_windows {
bx.load(addr.immediate(), bx.tcx().data_layout.pointer_align.abi)
} else {
addr.immediate()
};
bx.va_arg(va_list, bx.cx.layout_of(target_ty).llvm_type(bx.cx))
}
}
}
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