999 lines
34 KiB
Rust
999 lines
34 KiB
Rust
// Copyright 2012-2016 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::{self, ValueRef, AttributePlace};
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use base;
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use builder::Builder;
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use common::{instance_ty, ty_fn_sig, type_is_fat_ptr, C_usize};
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use context::CrateContext;
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use cabi_x86;
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use cabi_x86_64;
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use cabi_x86_win64;
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use cabi_arm;
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use cabi_aarch64;
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use cabi_powerpc;
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use cabi_powerpc64;
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use cabi_s390x;
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use cabi_mips;
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use cabi_mips64;
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use cabi_asmjs;
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use cabi_msp430;
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use cabi_sparc;
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use cabi_sparc64;
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use cabi_nvptx;
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use cabi_nvptx64;
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use cabi_hexagon;
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use machine::llalign_of_min;
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use type_::Type;
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use type_of;
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use rustc::hir;
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use rustc::ty::{self, Ty};
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use rustc::ty::layout::{self, Layout, LayoutTyper, TyLayout, Size};
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use libc::c_uint;
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use std::cmp;
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use std::iter;
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pub use syntax::abi::Abi;
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pub use rustc::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
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#[derive(Clone, Copy, PartialEq, Debug)]
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enum ArgKind {
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/// Pass the argument directly using the normal converted
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/// LLVM type or by coercing to another specified type
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Direct,
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/// Pass the argument indirectly via a hidden pointer
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Indirect,
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/// Ignore the argument (useful for empty struct)
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Ignore,
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}
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// Hack to disable non_upper_case_globals only for the bitflags! and not for the rest
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// of this module
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pub use self::attr_impl::ArgAttribute;
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#[allow(non_upper_case_globals)]
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#[allow(unused)]
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mod attr_impl {
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// The subset of llvm::Attribute needed for arguments, packed into a bitfield.
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bitflags! {
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#[derive(Default)]
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pub struct ArgAttribute: u16 {
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const ByVal = 1 << 0;
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const NoAlias = 1 << 1;
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const NoCapture = 1 << 2;
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const NonNull = 1 << 3;
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const ReadOnly = 1 << 4;
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const SExt = 1 << 5;
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const StructRet = 1 << 6;
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const ZExt = 1 << 7;
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const InReg = 1 << 8;
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}
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}
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}
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macro_rules! for_each_kind {
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($flags: ident, $f: ident, $($kind: ident),+) => ({
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$(if $flags.contains(ArgAttribute::$kind) { $f(llvm::Attribute::$kind) })+
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})
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}
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impl ArgAttribute {
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fn for_each_kind<F>(&self, mut f: F) where F: FnMut(llvm::Attribute) {
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for_each_kind!(self, f,
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ByVal, NoAlias, NoCapture, NonNull, ReadOnly, SExt, StructRet, ZExt, InReg)
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}
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}
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/// A compact representation of LLVM attributes (at least those relevant for this module)
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/// that can be manipulated without interacting with LLVM's Attribute machinery.
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#[derive(Copy, Clone, Debug, Default)]
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pub struct ArgAttributes {
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regular: ArgAttribute,
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dereferenceable_bytes: u64,
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}
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impl ArgAttributes {
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pub fn set(&mut self, attr: ArgAttribute) -> &mut Self {
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self.regular = self.regular | attr;
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self
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}
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pub fn set_dereferenceable(&mut self, bytes: u64) -> &mut Self {
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self.dereferenceable_bytes = bytes;
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self
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}
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pub fn apply_llfn(&self, idx: AttributePlace, llfn: ValueRef) {
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unsafe {
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self.regular.for_each_kind(|attr| attr.apply_llfn(idx, llfn));
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if self.dereferenceable_bytes != 0 {
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llvm::LLVMRustAddDereferenceableAttr(llfn,
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idx.as_uint(),
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self.dereferenceable_bytes);
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}
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}
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}
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pub fn apply_callsite(&self, idx: AttributePlace, callsite: ValueRef) {
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unsafe {
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self.regular.for_each_kind(|attr| attr.apply_callsite(idx, callsite));
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if self.dereferenceable_bytes != 0 {
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llvm::LLVMRustAddDereferenceableCallSiteAttr(callsite,
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idx.as_uint(),
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self.dereferenceable_bytes);
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}
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}
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}
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}
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#[derive(Copy, Clone, PartialEq, Eq, Debug)]
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pub enum RegKind {
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Integer,
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Float,
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Vector
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}
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#[derive(Copy, Clone, PartialEq, Eq, Debug)]
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pub struct Reg {
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pub kind: RegKind,
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pub size: Size,
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}
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macro_rules! reg_ctor {
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($name:ident, $kind:ident, $bits:expr) => {
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pub fn $name() -> Reg {
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Reg {
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kind: RegKind::$kind,
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size: Size::from_bits($bits)
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}
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}
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}
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}
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impl Reg {
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reg_ctor!(i8, Integer, 8);
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reg_ctor!(i16, Integer, 16);
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reg_ctor!(i32, Integer, 32);
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reg_ctor!(i64, Integer, 64);
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reg_ctor!(f32, Float, 32);
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reg_ctor!(f64, Float, 64);
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}
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impl Reg {
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fn llvm_type(&self, ccx: &CrateContext) -> Type {
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match self.kind {
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RegKind::Integer => Type::ix(ccx, self.size.bits()),
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RegKind::Float => {
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match self.size.bits() {
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32 => Type::f32(ccx),
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64 => Type::f64(ccx),
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_ => bug!("unsupported float: {:?}", self)
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}
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}
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RegKind::Vector => {
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Type::vector(&Type::i8(ccx), self.size.bytes())
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}
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}
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}
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}
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/// An argument passed entirely registers with the
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/// same kind (e.g. HFA / HVA on PPC64 and AArch64).
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#[derive(Copy, Clone)]
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pub struct Uniform {
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pub unit: Reg,
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/// The total size of the argument, which can be:
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/// * equal to `unit.size` (one scalar/vector)
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/// * a multiple of `unit.size` (an array of scalar/vectors)
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/// * if `unit.kind` is `Integer`, the last element
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/// can be shorter, i.e. `{ i64, i64, i32 }` for
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/// 64-bit integers with a total size of 20 bytes
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pub total: Size,
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}
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impl From<Reg> for Uniform {
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fn from(unit: Reg) -> Uniform {
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Uniform {
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unit,
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total: unit.size
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}
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}
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}
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impl Uniform {
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fn llvm_type(&self, ccx: &CrateContext) -> Type {
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let llunit = self.unit.llvm_type(ccx);
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if self.total <= self.unit.size {
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return llunit;
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}
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let count = self.total.bytes() / self.unit.size.bytes();
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let rem_bytes = self.total.bytes() % self.unit.size.bytes();
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if rem_bytes == 0 {
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return Type::array(&llunit, count);
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}
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// Only integers can be really split further.
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assert_eq!(self.unit.kind, RegKind::Integer);
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let args: Vec<_> = (0..count).map(|_| llunit)
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.chain(iter::once(Type::ix(ccx, rem_bytes * 8)))
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.collect();
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Type::struct_(ccx, &args, false)
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}
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}
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pub trait LayoutExt<'tcx> {
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fn is_aggregate(&self) -> bool;
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fn homogeneous_aggregate<'a>(&self, ccx: &CrateContext<'a, 'tcx>) -> Option<Reg>;
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}
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impl<'tcx> LayoutExt<'tcx> for TyLayout<'tcx> {
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fn is_aggregate(&self) -> bool {
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match *self.layout {
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Layout::Scalar { .. } |
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Layout::RawNullablePointer { .. } |
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Layout::CEnum { .. } |
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Layout::Vector { .. } => false,
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Layout::Array { .. } |
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Layout::FatPointer { .. } |
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Layout::Univariant { .. } |
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Layout::UntaggedUnion { .. } |
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Layout::General { .. } |
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Layout::StructWrappedNullablePointer { .. } => true
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}
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}
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fn homogeneous_aggregate<'a>(&self, ccx: &CrateContext<'a, 'tcx>) -> Option<Reg> {
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match *self.layout {
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// The primitives for this algorithm.
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Layout::Scalar { value, .. } |
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Layout::RawNullablePointer { value, .. } => {
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let kind = match value {
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layout::Int(_) |
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layout::Pointer => RegKind::Integer,
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layout::F32 |
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layout::F64 => RegKind::Float
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};
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Some(Reg {
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kind,
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size: self.size(ccx)
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})
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}
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Layout::CEnum { .. } => {
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Some(Reg {
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kind: RegKind::Integer,
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size: self.size(ccx)
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})
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}
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Layout::Vector { .. } => {
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Some(Reg {
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kind: RegKind::Vector,
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size: self.size(ccx)
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})
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}
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Layout::Array { count, .. } => {
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if count > 0 {
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self.field(ccx, 0).homogeneous_aggregate(ccx)
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} else {
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None
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}
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}
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Layout::Univariant { ref variant, .. } => {
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let mut unaligned_offset = Size::from_bytes(0);
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let mut result = None;
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for i in 0..self.field_count() {
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if unaligned_offset != variant.offsets[i] {
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return None;
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}
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let field = self.field(ccx, i);
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match (result, field.homogeneous_aggregate(ccx)) {
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// The field itself must be a homogeneous aggregate.
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(_, None) => return None,
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// If this is the first field, record the unit.
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(None, Some(unit)) => {
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result = Some(unit);
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}
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// For all following fields, the unit must be the same.
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(Some(prev_unit), Some(unit)) => {
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if prev_unit != unit {
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return None;
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}
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}
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}
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// Keep track of the offset (without padding).
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let size = field.size(ccx);
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match unaligned_offset.checked_add(size, ccx) {
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Some(offset) => unaligned_offset = offset,
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None => return None
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}
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}
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// There needs to be no padding.
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if unaligned_offset != self.size(ccx) {
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None
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} else {
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result
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}
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}
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Layout::UntaggedUnion { .. } => {
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let mut max = Size::from_bytes(0);
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let mut result = None;
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for i in 0..self.field_count() {
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let field = self.field(ccx, i);
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match (result, field.homogeneous_aggregate(ccx)) {
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// The field itself must be a homogeneous aggregate.
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(_, None) => return None,
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// If this is the first field, record the unit.
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(None, Some(unit)) => {
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result = Some(unit);
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}
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// For all following fields, the unit must be the same.
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(Some(prev_unit), Some(unit)) => {
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if prev_unit != unit {
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return None;
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}
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}
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}
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// Keep track of the offset (without padding).
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let size = field.size(ccx);
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if size > max {
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max = size;
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}
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}
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// There needs to be no padding.
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if max != self.size(ccx) {
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None
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} else {
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result
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}
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}
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// Rust-specific types, which we can ignore for C ABIs.
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Layout::FatPointer { .. } |
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Layout::General { .. } |
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Layout::StructWrappedNullablePointer { .. } => None
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}
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}
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}
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pub enum CastTarget {
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Uniform(Uniform),
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Pair(Reg, Reg)
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}
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impl From<Reg> for CastTarget {
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fn from(unit: Reg) -> CastTarget {
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CastTarget::Uniform(Uniform::from(unit))
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}
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}
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impl From<Uniform> for CastTarget {
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fn from(uniform: Uniform) -> CastTarget {
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CastTarget::Uniform(uniform)
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}
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}
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impl CastTarget {
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fn llvm_type(&self, ccx: &CrateContext) -> Type {
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match *self {
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CastTarget::Uniform(u) => u.llvm_type(ccx),
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CastTarget::Pair(a, b) => {
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Type::struct_(ccx, &[
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a.llvm_type(ccx),
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b.llvm_type(ccx)
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], false)
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}
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}
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}
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}
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/// Information about how a specific C type
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/// should be passed to or returned from a function
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///
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/// This is borrowed from clang's ABIInfo.h
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#[derive(Clone, Copy, Debug)]
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pub struct ArgType<'tcx> {
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kind: ArgKind,
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pub layout: TyLayout<'tcx>,
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/// Coerced LLVM Type
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pub cast: Option<Type>,
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/// Dummy argument, which is emitted before the real argument
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pub pad: Option<Type>,
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/// LLVM attributes of argument
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pub attrs: ArgAttributes
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}
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impl<'a, 'tcx> ArgType<'tcx> {
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fn new(layout: TyLayout<'tcx>) -> ArgType<'tcx> {
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ArgType {
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kind: ArgKind::Direct,
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layout,
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cast: None,
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pad: None,
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attrs: ArgAttributes::default()
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}
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}
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pub fn make_indirect(&mut self, ccx: &CrateContext<'a, 'tcx>) {
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assert_eq!(self.kind, ArgKind::Direct);
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// Wipe old attributes, likely not valid through indirection.
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self.attrs = ArgAttributes::default();
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let llarg_sz = self.layout.size(ccx).bytes();
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// For non-immediate arguments the callee gets its own copy of
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// the value on the stack, so there are no aliases. It's also
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// program-invisible so can't possibly capture
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self.attrs.set(ArgAttribute::NoAlias)
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.set(ArgAttribute::NoCapture)
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.set_dereferenceable(llarg_sz);
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self.kind = ArgKind::Indirect;
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}
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pub fn ignore(&mut self) {
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assert_eq!(self.kind, ArgKind::Direct);
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self.kind = ArgKind::Ignore;
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}
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pub fn extend_integer_width_to(&mut self, bits: u64) {
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// Only integers have signedness
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let (i, signed) = match *self.layout {
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Layout::Scalar { value, .. } => {
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match value {
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layout::Int(i) => {
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if self.layout.ty.is_integral() {
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(i, self.layout.ty.is_signed())
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} else {
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return;
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}
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}
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_ => return
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}
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}
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// Rust enum types that map onto C enums also need to follow
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// the target ABI zero-/sign-extension rules.
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Layout::CEnum { discr, signed, .. } => (discr, signed),
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_ => return
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};
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if i.size().bits() < bits {
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self.attrs.set(if signed {
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ArgAttribute::SExt
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} else {
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ArgAttribute::ZExt
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});
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}
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}
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pub fn cast_to<T: Into<CastTarget>>(&mut self, ccx: &CrateContext, target: T) {
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self.cast = Some(target.into().llvm_type(ccx));
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}
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pub fn pad_with(&mut self, ccx: &CrateContext, reg: Reg) {
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self.pad = Some(reg.llvm_type(ccx));
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}
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pub fn is_indirect(&self) -> bool {
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self.kind == ArgKind::Indirect
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}
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pub fn is_ignore(&self) -> bool {
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self.kind == ArgKind::Ignore
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}
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/// Get the LLVM type for an lvalue of the original Rust type of
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/// this argument/return, i.e. the result of `type_of::type_of`.
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pub fn memory_ty(&self, ccx: &CrateContext<'a, 'tcx>) -> Type {
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type_of::type_of(ccx, self.layout.ty)
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}
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/// Store a direct/indirect value described by this ArgType into a
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/// lvalue for the original Rust type of this argument/return.
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/// Can be used for both storing formal arguments into Rust variables
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/// or results of call/invoke instructions into their destinations.
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pub fn store(&self, bcx: &Builder<'a, 'tcx>, mut val: ValueRef, dst: ValueRef) {
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if self.is_ignore() {
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return;
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}
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let ccx = bcx.ccx;
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if self.is_indirect() {
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let llsz = C_usize(ccx, self.layout.size(ccx).bytes());
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let llalign = self.layout.align(ccx).abi();
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base::call_memcpy(bcx, dst, val, llsz, llalign as u32);
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} else if let Some(ty) = self.cast {
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// FIXME(eddyb): Figure out when the simpler Store is safe, clang
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// uses it for i16 -> {i8, i8}, but not for i24 -> {i8, i8, i8}.
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let can_store_through_cast_ptr = false;
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if can_store_through_cast_ptr {
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let cast_dst = bcx.pointercast(dst, ty.ptr_to());
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let llalign = self.layout.align(ccx).abi();
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bcx.store(val, cast_dst, Some(llalign as u32));
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} else {
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// The actual return type is a struct, but the ABI
|
|
// adaptation code has cast it into some scalar type. The
|
|
// code that follows is the only reliable way I have
|
|
// found to do a transform like i64 -> {i32,i32}.
|
|
// Basically we dump the data onto the stack then memcpy it.
|
|
//
|
|
// Other approaches I tried:
|
|
// - Casting rust ret pointer to the foreign type and using Store
|
|
// is (a) unsafe if size of foreign type > size of rust type and
|
|
// (b) runs afoul of strict aliasing rules, yielding invalid
|
|
// assembly under -O (specifically, the store gets removed).
|
|
// - Truncating foreign type to correct integral type and then
|
|
// bitcasting to the struct type yields invalid cast errors.
|
|
|
|
// We instead thus allocate some scratch space...
|
|
let llscratch = bcx.alloca(ty, "abi_cast", None);
|
|
base::Lifetime::Start.call(bcx, llscratch);
|
|
|
|
// ...where we first store the value...
|
|
bcx.store(val, llscratch, None);
|
|
|
|
// ...and then memcpy it to the intended destination.
|
|
base::call_memcpy(bcx,
|
|
bcx.pointercast(dst, Type::i8p(ccx)),
|
|
bcx.pointercast(llscratch, Type::i8p(ccx)),
|
|
C_usize(ccx, self.layout.size(ccx).bytes()),
|
|
cmp::min(self.layout.align(ccx).abi() as u32,
|
|
llalign_of_min(ccx, ty)));
|
|
|
|
base::Lifetime::End.call(bcx, llscratch);
|
|
}
|
|
} else {
|
|
if self.layout.ty == ccx.tcx().types.bool {
|
|
val = bcx.zext(val, Type::i8(ccx));
|
|
}
|
|
bcx.store(val, dst, None);
|
|
}
|
|
}
|
|
|
|
pub fn store_fn_arg(&self, bcx: &Builder<'a, 'tcx>, idx: &mut usize, dst: ValueRef) {
|
|
if self.pad.is_some() {
|
|
*idx += 1;
|
|
}
|
|
if self.is_ignore() {
|
|
return;
|
|
}
|
|
let val = llvm::get_param(bcx.llfn(), *idx as c_uint);
|
|
*idx += 1;
|
|
self.store(bcx, val, dst);
|
|
}
|
|
}
|
|
|
|
/// Metadata describing how the arguments to a native function
|
|
/// should be passed in order to respect the native ABI.
|
|
///
|
|
/// I will do my best to describe this structure, but these
|
|
/// comments are reverse-engineered and may be inaccurate. -NDM
|
|
#[derive(Clone, Debug)]
|
|
pub struct FnType<'tcx> {
|
|
/// The LLVM types of each argument.
|
|
pub args: Vec<ArgType<'tcx>>,
|
|
|
|
/// LLVM return type.
|
|
pub ret: ArgType<'tcx>,
|
|
|
|
pub variadic: bool,
|
|
|
|
pub cconv: llvm::CallConv
|
|
}
|
|
|
|
impl<'a, 'tcx> FnType<'tcx> {
|
|
pub fn of_instance(ccx: &CrateContext<'a, 'tcx>, instance: &ty::Instance<'tcx>)
|
|
-> Self {
|
|
let fn_ty = instance_ty(ccx.shared(), &instance);
|
|
let sig = ty_fn_sig(ccx, fn_ty);
|
|
let sig = ccx.tcx().erase_late_bound_regions_and_normalize(&sig);
|
|
Self::new(ccx, sig, &[])
|
|
}
|
|
|
|
pub fn new(ccx: &CrateContext<'a, 'tcx>,
|
|
sig: ty::FnSig<'tcx>,
|
|
extra_args: &[Ty<'tcx>]) -> FnType<'tcx> {
|
|
let mut fn_ty = FnType::unadjusted(ccx, sig, extra_args);
|
|
fn_ty.adjust_for_abi(ccx, sig);
|
|
fn_ty
|
|
}
|
|
|
|
pub fn new_vtable(ccx: &CrateContext<'a, 'tcx>,
|
|
sig: ty::FnSig<'tcx>,
|
|
extra_args: &[Ty<'tcx>]) -> FnType<'tcx> {
|
|
let mut fn_ty = FnType::unadjusted(ccx, sig, extra_args);
|
|
// Don't pass the vtable, it's not an argument of the virtual fn.
|
|
fn_ty.args[1].ignore();
|
|
fn_ty.adjust_for_abi(ccx, sig);
|
|
fn_ty
|
|
}
|
|
|
|
pub fn unadjusted(ccx: &CrateContext<'a, 'tcx>,
|
|
sig: ty::FnSig<'tcx>,
|
|
extra_args: &[Ty<'tcx>]) -> FnType<'tcx> {
|
|
debug!("FnType::unadjusted({:?}, {:?})", sig, extra_args);
|
|
|
|
use self::Abi::*;
|
|
let cconv = match ccx.sess().target.target.adjust_abi(sig.abi) {
|
|
RustIntrinsic | PlatformIntrinsic |
|
|
Rust | RustCall => llvm::CCallConv,
|
|
|
|
// It's the ABI's job to select this, not us.
|
|
System => bug!("system abi should be selected elsewhere"),
|
|
|
|
Stdcall => llvm::X86StdcallCallConv,
|
|
Fastcall => llvm::X86FastcallCallConv,
|
|
Vectorcall => llvm::X86_VectorCall,
|
|
Thiscall => llvm::X86_ThisCall,
|
|
C => llvm::CCallConv,
|
|
Unadjusted => llvm::CCallConv,
|
|
Win64 => llvm::X86_64_Win64,
|
|
SysV64 => llvm::X86_64_SysV,
|
|
Aapcs => llvm::ArmAapcsCallConv,
|
|
PtxKernel => llvm::PtxKernel,
|
|
Msp430Interrupt => llvm::Msp430Intr,
|
|
X86Interrupt => llvm::X86_Intr,
|
|
|
|
// These API constants ought to be more specific...
|
|
Cdecl => llvm::CCallConv,
|
|
};
|
|
|
|
let mut inputs = sig.inputs();
|
|
let extra_args = if sig.abi == RustCall {
|
|
assert!(!sig.variadic && extra_args.is_empty());
|
|
|
|
match sig.inputs().last().unwrap().sty {
|
|
ty::TyTuple(ref tupled_arguments, _) => {
|
|
inputs = &sig.inputs()[0..sig.inputs().len() - 1];
|
|
tupled_arguments
|
|
}
|
|
_ => {
|
|
bug!("argument to function with \"rust-call\" ABI \
|
|
is not a tuple");
|
|
}
|
|
}
|
|
} else {
|
|
assert!(sig.variadic || extra_args.is_empty());
|
|
extra_args
|
|
};
|
|
|
|
let target = &ccx.sess().target.target;
|
|
let win_x64_gnu = target.target_os == "windows"
|
|
&& target.arch == "x86_64"
|
|
&& target.target_env == "gnu";
|
|
let linux_s390x = target.target_os == "linux"
|
|
&& target.arch == "s390x"
|
|
&& target.target_env == "gnu";
|
|
let rust_abi = match sig.abi {
|
|
RustIntrinsic | PlatformIntrinsic | Rust | RustCall => true,
|
|
_ => false
|
|
};
|
|
|
|
let arg_of = |ty: Ty<'tcx>, is_return: bool| {
|
|
let mut arg = ArgType::new(ccx.layout_of(ty));
|
|
if ty.is_bool() {
|
|
arg.attrs.set(ArgAttribute::ZExt);
|
|
} else {
|
|
if arg.layout.size(ccx).bytes() == 0 {
|
|
// For some forsaken reason, x86_64-pc-windows-gnu
|
|
// doesn't ignore zero-sized struct arguments.
|
|
// The same is true for s390x-unknown-linux-gnu.
|
|
if is_return || rust_abi ||
|
|
(!win_x64_gnu && !linux_s390x) {
|
|
arg.ignore();
|
|
}
|
|
}
|
|
}
|
|
arg
|
|
};
|
|
|
|
let ret_ty = sig.output();
|
|
let mut ret = arg_of(ret_ty, true);
|
|
|
|
if !type_is_fat_ptr(ccx, ret_ty) {
|
|
// The `noalias` attribute on the return value is useful to a
|
|
// function ptr caller.
|
|
if ret_ty.is_box() {
|
|
// `Box` pointer return values never alias because ownership
|
|
// is transferred
|
|
ret.attrs.set(ArgAttribute::NoAlias);
|
|
}
|
|
|
|
// We can also mark the return value as `dereferenceable` in certain cases
|
|
match ret_ty.sty {
|
|
// These are not really pointers but pairs, (pointer, len)
|
|
ty::TyRef(_, ty::TypeAndMut { ty, .. }) => {
|
|
ret.attrs.set_dereferenceable(ccx.size_of(ty));
|
|
}
|
|
ty::TyAdt(def, _) if def.is_box() => {
|
|
ret.attrs.set_dereferenceable(ccx.size_of(ret_ty.boxed_ty()));
|
|
}
|
|
_ => {}
|
|
}
|
|
}
|
|
|
|
let mut args = Vec::with_capacity(inputs.len() + extra_args.len());
|
|
|
|
// Handle safe Rust thin and fat pointers.
|
|
let rust_ptr_attrs = |ty: Ty<'tcx>, arg: &mut ArgType| match ty.sty {
|
|
// `Box` pointer parameters never alias because ownership is transferred
|
|
ty::TyAdt(def, _) if def.is_box() => {
|
|
arg.attrs.set(ArgAttribute::NoAlias);
|
|
Some(ty.boxed_ty())
|
|
}
|
|
|
|
ty::TyRef(b, mt) => {
|
|
use rustc::ty::{BrAnon, ReLateBound};
|
|
|
|
// `&mut` pointer parameters never alias other parameters, or mutable global data
|
|
//
|
|
// `&T` where `T` contains no `UnsafeCell<U>` is immutable, and can be marked as
|
|
// both `readonly` and `noalias`, as LLVM's definition of `noalias` is based solely
|
|
// on memory dependencies rather than pointer equality
|
|
let is_freeze = ccx.shared().type_is_freeze(mt.ty);
|
|
|
|
if mt.mutbl != hir::MutMutable && is_freeze {
|
|
arg.attrs.set(ArgAttribute::NoAlias);
|
|
}
|
|
|
|
if mt.mutbl == hir::MutImmutable && is_freeze {
|
|
arg.attrs.set(ArgAttribute::ReadOnly);
|
|
}
|
|
|
|
// When a reference in an argument has no named lifetime, it's
|
|
// impossible for that reference to escape this function
|
|
// (returned or stored beyond the call by a closure).
|
|
if let ReLateBound(_, BrAnon(_)) = *b {
|
|
arg.attrs.set(ArgAttribute::NoCapture);
|
|
}
|
|
|
|
Some(mt.ty)
|
|
}
|
|
_ => None
|
|
};
|
|
|
|
for ty in inputs.iter().chain(extra_args.iter()) {
|
|
let mut arg = arg_of(ty, false);
|
|
|
|
if let ty::layout::FatPointer { .. } = *arg.layout {
|
|
let mut data = ArgType::new(arg.layout.field(ccx, 0));
|
|
let mut info = ArgType::new(arg.layout.field(ccx, 1));
|
|
|
|
if let Some(inner) = rust_ptr_attrs(ty, &mut data) {
|
|
data.attrs.set(ArgAttribute::NonNull);
|
|
if ccx.tcx().struct_tail(inner).is_trait() {
|
|
// vtables can be safely marked non-null, readonly
|
|
// and noalias.
|
|
info.attrs.set(ArgAttribute::NonNull);
|
|
info.attrs.set(ArgAttribute::ReadOnly);
|
|
info.attrs.set(ArgAttribute::NoAlias);
|
|
}
|
|
}
|
|
args.push(data);
|
|
args.push(info);
|
|
} else {
|
|
if let Some(inner) = rust_ptr_attrs(ty, &mut arg) {
|
|
arg.attrs.set_dereferenceable(ccx.size_of(inner));
|
|
}
|
|
args.push(arg);
|
|
}
|
|
}
|
|
|
|
FnType {
|
|
args,
|
|
ret,
|
|
variadic: sig.variadic,
|
|
cconv,
|
|
}
|
|
}
|
|
|
|
fn adjust_for_abi(&mut self,
|
|
ccx: &CrateContext<'a, 'tcx>,
|
|
sig: ty::FnSig<'tcx>) {
|
|
let abi = sig.abi;
|
|
if abi == Abi::Unadjusted { return }
|
|
|
|
if abi == Abi::Rust || abi == Abi::RustCall ||
|
|
abi == Abi::RustIntrinsic || abi == Abi::PlatformIntrinsic {
|
|
let fixup = |arg: &mut ArgType<'tcx>| {
|
|
if !arg.layout.is_aggregate() {
|
|
return;
|
|
}
|
|
|
|
let size = arg.layout.size(ccx);
|
|
|
|
if let Some(unit) = arg.layout.homogeneous_aggregate(ccx) {
|
|
// Replace newtypes with their inner-most type.
|
|
if unit.size == size {
|
|
// Needs a cast as we've unpacked a newtype.
|
|
arg.cast_to(ccx, unit);
|
|
return;
|
|
}
|
|
|
|
// Pairs of floats.
|
|
if unit.kind == RegKind::Float {
|
|
if unit.size.checked_mul(2, ccx) == Some(size) {
|
|
// FIXME(eddyb) This should be using Uniform instead of a pair,
|
|
// but the resulting [2 x float/double] breaks emscripten.
|
|
// See https://github.com/kripken/emscripten-fastcomp/issues/178.
|
|
arg.cast_to(ccx, CastTarget::Pair(unit, unit));
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
if size > layout::Pointer.size(ccx) {
|
|
arg.make_indirect(ccx);
|
|
} else {
|
|
// We want to pass small aggregates as immediates, but using
|
|
// a LLVM aggregate type for this leads to bad optimizations,
|
|
// so we pick an appropriately sized integer type instead.
|
|
arg.cast_to(ccx, Reg {
|
|
kind: RegKind::Integer,
|
|
size
|
|
});
|
|
}
|
|
};
|
|
// Fat pointers are returned by-value.
|
|
if !self.ret.is_ignore() {
|
|
if !type_is_fat_ptr(ccx, sig.output()) {
|
|
fixup(&mut self.ret);
|
|
}
|
|
}
|
|
for arg in &mut self.args {
|
|
if arg.is_ignore() { continue; }
|
|
fixup(arg);
|
|
}
|
|
if self.ret.is_indirect() {
|
|
self.ret.attrs.set(ArgAttribute::StructRet);
|
|
}
|
|
return;
|
|
}
|
|
|
|
match &ccx.sess().target.target.arch[..] {
|
|
"x86" => {
|
|
let flavor = if abi == Abi::Fastcall {
|
|
cabi_x86::Flavor::Fastcall
|
|
} else {
|
|
cabi_x86::Flavor::General
|
|
};
|
|
cabi_x86::compute_abi_info(ccx, self, flavor);
|
|
},
|
|
"x86_64" => if abi == Abi::SysV64 {
|
|
cabi_x86_64::compute_abi_info(ccx, self);
|
|
} else if abi == Abi::Win64 || ccx.sess().target.target.options.is_like_windows {
|
|
cabi_x86_win64::compute_abi_info(ccx, self);
|
|
} else {
|
|
cabi_x86_64::compute_abi_info(ccx, self);
|
|
},
|
|
"aarch64" => cabi_aarch64::compute_abi_info(ccx, self),
|
|
"arm" => cabi_arm::compute_abi_info(ccx, self),
|
|
"mips" => cabi_mips::compute_abi_info(ccx, self),
|
|
"mips64" => cabi_mips64::compute_abi_info(ccx, self),
|
|
"powerpc" => cabi_powerpc::compute_abi_info(ccx, self),
|
|
"powerpc64" => cabi_powerpc64::compute_abi_info(ccx, self),
|
|
"s390x" => cabi_s390x::compute_abi_info(ccx, self),
|
|
"asmjs" => cabi_asmjs::compute_abi_info(ccx, self),
|
|
"wasm32" => cabi_asmjs::compute_abi_info(ccx, self),
|
|
"msp430" => cabi_msp430::compute_abi_info(ccx, self),
|
|
"sparc" => cabi_sparc::compute_abi_info(ccx, self),
|
|
"sparc64" => cabi_sparc64::compute_abi_info(ccx, self),
|
|
"nvptx" => cabi_nvptx::compute_abi_info(ccx, self),
|
|
"nvptx64" => cabi_nvptx64::compute_abi_info(ccx, self),
|
|
"hexagon" => cabi_hexagon::compute_abi_info(ccx, self),
|
|
a => ccx.sess().fatal(&format!("unrecognized arch \"{}\" in target specification", a))
|
|
}
|
|
|
|
if self.ret.is_indirect() {
|
|
self.ret.attrs.set(ArgAttribute::StructRet);
|
|
}
|
|
}
|
|
|
|
pub fn llvm_type(&self, ccx: &CrateContext<'a, 'tcx>) -> Type {
|
|
let mut llargument_tys = Vec::new();
|
|
|
|
let llreturn_ty = if self.ret.is_ignore() {
|
|
Type::void(ccx)
|
|
} else if self.ret.is_indirect() {
|
|
llargument_tys.push(self.ret.memory_ty(ccx).ptr_to());
|
|
Type::void(ccx)
|
|
} else {
|
|
self.ret.cast.unwrap_or_else(|| {
|
|
type_of::immediate_type_of(ccx, self.ret.layout.ty)
|
|
})
|
|
};
|
|
|
|
for arg in &self.args {
|
|
if arg.is_ignore() {
|
|
continue;
|
|
}
|
|
// add padding
|
|
if let Some(ty) = arg.pad {
|
|
llargument_tys.push(ty);
|
|
}
|
|
|
|
let llarg_ty = if arg.is_indirect() {
|
|
arg.memory_ty(ccx).ptr_to()
|
|
} else {
|
|
arg.cast.unwrap_or_else(|| {
|
|
type_of::immediate_type_of(ccx, arg.layout.ty)
|
|
})
|
|
};
|
|
|
|
llargument_tys.push(llarg_ty);
|
|
}
|
|
|
|
if self.variadic {
|
|
Type::variadic_func(&llargument_tys, &llreturn_ty)
|
|
} else {
|
|
Type::func(&llargument_tys, &llreturn_ty)
|
|
}
|
|
}
|
|
|
|
pub fn apply_attrs_llfn(&self, llfn: ValueRef) {
|
|
let mut i = if self.ret.is_indirect() { 1 } else { 0 };
|
|
if !self.ret.is_ignore() {
|
|
self.ret.attrs.apply_llfn(llvm::AttributePlace::Argument(i), llfn);
|
|
}
|
|
i += 1;
|
|
for arg in &self.args {
|
|
if !arg.is_ignore() {
|
|
if arg.pad.is_some() { i += 1; }
|
|
arg.attrs.apply_llfn(llvm::AttributePlace::Argument(i), llfn);
|
|
i += 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn apply_attrs_callsite(&self, callsite: ValueRef) {
|
|
let mut i = if self.ret.is_indirect() { 1 } else { 0 };
|
|
if !self.ret.is_ignore() {
|
|
self.ret.attrs.apply_callsite(llvm::AttributePlace::Argument(i), callsite);
|
|
}
|
|
i += 1;
|
|
for arg in &self.args {
|
|
if !arg.is_ignore() {
|
|
if arg.pad.is_some() { i += 1; }
|
|
arg.attrs.apply_callsite(llvm::AttributePlace::Argument(i), callsite);
|
|
i += 1;
|
|
}
|
|
}
|
|
|
|
if self.cconv != llvm::CCallConv {
|
|
llvm::SetInstructionCallConv(callsite, self.cconv);
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn align_up_to(off: u64, a: u64) -> u64 {
|
|
(off + a - 1) / a * a
|
|
}
|