103 lines
3.2 KiB
Rust
103 lines
3.2 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 llvm::*;
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use abi::{ArgAttribute, FnType};
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use type_::Type;
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use super::common::*;
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use super::machine::*;
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#[derive(PartialEq)]
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pub enum Flavor {
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General,
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Fastcall
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}
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pub fn compute_abi_info(ccx: &CrateContext, fty: &mut FnType, flavor: Flavor) {
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if !fty.ret.is_ignore() {
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if fty.ret.ty.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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let t = &ccx.sess().target.target;
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if t.options.is_like_osx || t.options.is_like_windows
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|| t.options.is_like_openbsd {
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match llsize_of_alloc(ccx, fty.ret.ty) {
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1 => fty.ret.cast = Some(Type::i8(ccx)),
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2 => fty.ret.cast = Some(Type::i16(ccx)),
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4 => fty.ret.cast = Some(Type::i32(ccx)),
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8 => fty.ret.cast = Some(Type::i64(ccx)),
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_ => fty.ret.make_indirect(ccx)
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}
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} else {
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fty.ret.make_indirect(ccx);
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}
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} else {
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fty.ret.extend_integer_width_to(32);
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}
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}
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for arg in &mut fty.args {
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if arg.is_ignore() { continue; }
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if arg.ty.kind() == Struct {
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arg.make_indirect(ccx);
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arg.attrs.set(ArgAttribute::ByVal);
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} else {
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arg.extend_integer_width_to(32);
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}
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}
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if flavor == Flavor::Fastcall {
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// Mark arguments as InReg like clang does it,
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// so our fastcall is compatible with C/C++ fastcall.
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// Clang reference: lib/CodeGen/TargetInfo.cpp
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// See X86_32ABIInfo::shouldPrimitiveUseInReg(), X86_32ABIInfo::updateFreeRegs()
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// IsSoftFloatABI is only set to true on ARM platforms,
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// which in turn can't be x86?
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let mut free_regs = 2;
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for arg in &mut fty.args {
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if arg.is_ignore() || arg.is_indirect() { continue; }
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if arg.ty.kind() == Float {
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continue;
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}
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let size = llbitsize_of_real(ccx, arg.ty);
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let size_in_regs = (size + 31) / 32;
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if size_in_regs == 0 {
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continue;
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}
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if size_in_regs > free_regs {
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break;
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}
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free_regs -= size_in_regs;
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if size <= 32 && (arg.ty.kind() == Pointer || arg.ty.kind() == Integer) {
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arg.attrs.set(ArgAttribute::InReg);
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}
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if free_regs == 0 {
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break;
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}
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}
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}
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}
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