blob: e5f5146fac8fb5dd4b38cf13e849edbf33504797 [file] [log] [blame]
use crate::attributes;
use crate::builder::Builder;
use crate::context::CodegenCx;
use crate::llvm::{self, Attribute, AttributePlace};
use crate::type_::Type;
use crate::type_of::LayoutLlvmExt;
use crate::value::Value;
use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
use rustc_codegen_ssa::mir::place::PlaceRef;
use rustc_codegen_ssa::traits::*;
use rustc_codegen_ssa::MemFlags;
use rustc_middle::bug;
use rustc_middle::ty::layout::LayoutOf;
pub use rustc_middle::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA};
use rustc_middle::ty::Ty;
use rustc_session::config;
pub use rustc_target::abi::call::*;
use rustc_target::abi::{self, HasDataLayout, Int};
pub use rustc_target::spec::abi::Abi;
use rustc_target::spec::SanitizerSet;
use libc::c_uint;
use smallvec::SmallVec;
pub trait ArgAttributesExt {
fn apply_attrs_to_llfn(&self, idx: AttributePlace, cx: &CodegenCx<'_, '_>, llfn: &Value);
fn apply_attrs_to_callsite(
&self,
idx: AttributePlace,
cx: &CodegenCx<'_, '_>,
callsite: &Value,
);
}
const ABI_AFFECTING_ATTRIBUTES: [(ArgAttribute, llvm::AttributeKind); 1] =
[(ArgAttribute::InReg, llvm::AttributeKind::InReg)];
const OPTIMIZATION_ATTRIBUTES: [(ArgAttribute, llvm::AttributeKind); 5] = [
(ArgAttribute::NoAlias, llvm::AttributeKind::NoAlias),
(ArgAttribute::NoCapture, llvm::AttributeKind::NoCapture),
(ArgAttribute::NonNull, llvm::AttributeKind::NonNull),
(ArgAttribute::ReadOnly, llvm::AttributeKind::ReadOnly),
(ArgAttribute::NoUndef, llvm::AttributeKind::NoUndef),
];
fn get_attrs<'ll>(this: &ArgAttributes, cx: &CodegenCx<'ll, '_>) -> SmallVec<[&'ll Attribute; 8]> {
let mut regular = this.regular;
let mut attrs = SmallVec::new();
// ABI-affecting attributes must always be applied
for (attr, llattr) in ABI_AFFECTING_ATTRIBUTES {
if regular.contains(attr) {
attrs.push(llattr.create_attr(cx.llcx));
}
}
if let Some(align) = this.pointee_align {
attrs.push(llvm::CreateAlignmentAttr(cx.llcx, align.bytes()));
}
match this.arg_ext {
ArgExtension::None => {}
ArgExtension::Zext => attrs.push(llvm::AttributeKind::ZExt.create_attr(cx.llcx)),
ArgExtension::Sext => attrs.push(llvm::AttributeKind::SExt.create_attr(cx.llcx)),
}
// Only apply remaining attributes when optimizing
if cx.sess().opts.optimize != config::OptLevel::No {
let deref = this.pointee_size.bytes();
if deref != 0 {
if regular.contains(ArgAttribute::NonNull) {
attrs.push(llvm::CreateDereferenceableAttr(cx.llcx, deref));
} else {
attrs.push(llvm::CreateDereferenceableOrNullAttr(cx.llcx, deref));
}
regular -= ArgAttribute::NonNull;
}
for (attr, llattr) in OPTIMIZATION_ATTRIBUTES {
if regular.contains(attr) {
attrs.push(llattr.create_attr(cx.llcx));
}
}
} else if cx.tcx.sess.opts.unstable_opts.sanitizer.contains(SanitizerSet::MEMORY) {
// If we're not optimising, *but* memory sanitizer is on, emit noundef, since it affects
// memory sanitizer's behavior.
if regular.contains(ArgAttribute::NoUndef) {
attrs.push(llvm::AttributeKind::NoUndef.create_attr(cx.llcx));
}
}
attrs
}
impl ArgAttributesExt for ArgAttributes {
fn apply_attrs_to_llfn(&self, idx: AttributePlace, cx: &CodegenCx<'_, '_>, llfn: &Value) {
let attrs = get_attrs(self, cx);
attributes::apply_to_llfn(llfn, idx, &attrs);
}
fn apply_attrs_to_callsite(
&self,
idx: AttributePlace,
cx: &CodegenCx<'_, '_>,
callsite: &Value,
) {
let attrs = get_attrs(self, cx);
attributes::apply_to_callsite(callsite, idx, &attrs);
}
}
pub trait LlvmType {
fn llvm_type<'ll>(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type;
}
impl LlvmType for Reg {
fn llvm_type<'ll>(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type {
match self.kind {
RegKind::Integer => cx.type_ix(self.size.bits()),
RegKind::Float => match self.size.bits() {
32 => cx.type_f32(),
64 => cx.type_f64(),
_ => bug!("unsupported float: {:?}", self),
},
RegKind::Vector => cx.type_vector(cx.type_i8(), self.size.bytes()),
}
}
}
impl LlvmType for CastTarget {
fn llvm_type<'ll>(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type {
let rest_ll_unit = self.rest.unit.llvm_type(cx);
let (rest_count, rem_bytes) = if self.rest.unit.size.bytes() == 0 {
(0, 0)
} else {
(
self.rest.total.bytes() / self.rest.unit.size.bytes(),
self.rest.total.bytes() % self.rest.unit.size.bytes(),
)
};
if self.prefix.iter().all(|x| x.is_none()) {
// Simplify to a single unit when there is no prefix and size <= unit size
if self.rest.total <= self.rest.unit.size {
return rest_ll_unit;
}
// Simplify to array when all chunks are the same size and type
if rem_bytes == 0 {
return cx.type_array(rest_ll_unit, rest_count);
}
}
// Create list of fields in the main structure
let mut args: Vec<_> = self
.prefix
.iter()
.flat_map(|option_reg| option_reg.map(|reg| reg.llvm_type(cx)))
.chain((0..rest_count).map(|_| rest_ll_unit))
.collect();
// Append final integer
if rem_bytes != 0 {
// Only integers can be really split further.
assert_eq!(self.rest.unit.kind, RegKind::Integer);
args.push(cx.type_ix(rem_bytes * 8));
}
cx.type_struct(&args, false)
}
}
pub trait ArgAbiExt<'ll, 'tcx> {
fn memory_ty(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
fn store(
&self,
bx: &mut Builder<'_, 'll, 'tcx>,
val: &'ll Value,
dst: PlaceRef<'tcx, &'ll Value>,
);
fn store_fn_arg(
&self,
bx: &mut Builder<'_, 'll, 'tcx>,
idx: &mut usize,
dst: PlaceRef<'tcx, &'ll Value>,
);
}
impl<'ll, 'tcx> ArgAbiExt<'ll, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> {
/// Gets the LLVM type for a place of the original Rust type of
/// this argument/return, i.e., the result of `type_of::type_of`.
fn memory_ty(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
self.layout.llvm_type(cx)
}
/// Stores a direct/indirect value described by this ArgAbi into a
/// place for the original Rust type of this argument/return.
/// Can be used for both storing formal arguments into Rust variables
/// or results of call/invoke instructions into their destinations.
fn store(
&self,
bx: &mut Builder<'_, 'll, 'tcx>,
val: &'ll Value,
dst: PlaceRef<'tcx, &'ll Value>,
) {
match &self.mode {
PassMode::Ignore => {}
// Sized indirect arguments
PassMode::Indirect { attrs, meta_attrs: None, on_stack: _ } => {
let align = attrs.pointee_align.unwrap_or(self.layout.align.abi);
OperandValue::Ref(val, None, align).store(bx, dst);
}
// Unsized indirect qrguments
PassMode::Indirect { attrs: _, meta_attrs: Some(_), on_stack: _ } => {
bug!("unsized `ArgAbi` must be handled through `store_fn_arg`");
}
PassMode::Cast { cast, pad_i32: _ } => {
// FIXME(eddyb): Figure out when the simpler Store is safe, clang
// uses it for i16 -> {i8, i8}, but not for i24 -> {i8, i8, i8}.
let can_store_through_cast_ptr = false;
if can_store_through_cast_ptr {
bx.store(val, dst.llval, self.layout.align.abi);
} else {
// 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 scratch_size = cast.size(bx);
let scratch_align = cast.align(bx);
let llscratch = bx.alloca(cast.llvm_type(bx), scratch_align);
bx.lifetime_start(llscratch, scratch_size);
// ... where we first store the value...
bx.store(val, llscratch, scratch_align);
// ... and then memcpy it to the intended destination.
bx.memcpy(
dst.llval,
self.layout.align.abi,
llscratch,
scratch_align,
bx.const_usize(self.layout.size.bytes()),
MemFlags::empty(),
);
bx.lifetime_end(llscratch, scratch_size);
}
}
_ => {
OperandRef::from_immediate_or_packed_pair(bx, val, self.layout).val.store(bx, dst);
}
}
}
fn store_fn_arg(
&self,
bx: &mut Builder<'_, 'll, 'tcx>,
idx: &mut usize,
dst: PlaceRef<'tcx, &'ll Value>,
) {
let mut next = || {
let val = llvm::get_param(bx.llfn(), *idx as c_uint);
*idx += 1;
val
};
match self.mode {
PassMode::Ignore => {}
PassMode::Pair(..) => {
OperandValue::Pair(next(), next()).store(bx, dst);
}
PassMode::Indirect { attrs: _, meta_attrs: Some(_), on_stack: _ } => {
OperandValue::Ref(next(), Some(next()), self.layout.align.abi).store(bx, dst);
}
PassMode::Direct(_)
| PassMode::Indirect { attrs: _, meta_attrs: None, on_stack: _ }
| PassMode::Cast { .. } => {
let next_arg = next();
self.store(bx, next_arg, dst);
}
}
}
}
impl<'ll, 'tcx> ArgAbiMethods<'tcx> for Builder<'_, 'll, 'tcx> {
fn store_fn_arg(
&mut self,
arg_abi: &ArgAbi<'tcx, Ty<'tcx>>,
idx: &mut usize,
dst: PlaceRef<'tcx, Self::Value>,
) {
arg_abi.store_fn_arg(self, idx, dst)
}
fn store_arg(
&mut self,
arg_abi: &ArgAbi<'tcx, Ty<'tcx>>,
val: &'ll Value,
dst: PlaceRef<'tcx, &'ll Value>,
) {
arg_abi.store(self, val, dst)
}
fn arg_memory_ty(&self, arg_abi: &ArgAbi<'tcx, Ty<'tcx>>) -> &'ll Type {
arg_abi.memory_ty(self)
}
}
pub trait FnAbiLlvmExt<'ll, 'tcx> {
fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
fn ptr_to_llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
fn llvm_cconv(&self) -> llvm::CallConv;
fn apply_attrs_llfn(&self, cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value);
fn apply_attrs_callsite(&self, bx: &mut Builder<'_, 'll, 'tcx>, callsite: &'ll Value);
}
impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
// Ignore "extra" args from the call site for C variadic functions.
// Only the "fixed" args are part of the LLVM function signature.
let args =
if self.c_variadic { &self.args[..self.fixed_count as usize] } else { &self.args };
// This capacity calculation is approximate.
let mut llargument_tys = Vec::with_capacity(
self.args.len() + if let PassMode::Indirect { .. } = self.ret.mode { 1 } else { 0 },
);
let llreturn_ty = match &self.ret.mode {
PassMode::Ignore => cx.type_void(),
PassMode::Direct(_) | PassMode::Pair(..) => self.ret.layout.immediate_llvm_type(cx),
PassMode::Cast { cast, pad_i32: _ } => cast.llvm_type(cx),
PassMode::Indirect { .. } => {
llargument_tys.push(cx.type_ptr());
cx.type_void()
}
};
for arg in args {
// Note that the exact number of arguments pushed here is carefully synchronized with
// code all over the place, both in the codegen_llvm and codegen_ssa crates. That's how
// other code then knows which LLVM argument(s) correspond to the n-th Rust argument.
let llarg_ty = match &arg.mode {
PassMode::Ignore => continue,
PassMode::Direct(_) => {
// ABI-compatible Rust types have the same `layout.abi` (up to validity ranges),
// and for Scalar ABIs the LLVM type is fully determined by `layout.abi`,
// guaranteeing that we generate ABI-compatible LLVM IR.
arg.layout.immediate_llvm_type(cx)
}
PassMode::Pair(..) => {
// ABI-compatible Rust types have the same `layout.abi` (up to validity ranges),
// so for ScalarPair we can easily be sure that we are generating ABI-compatible
// LLVM IR.
llargument_tys.push(arg.layout.scalar_pair_element_llvm_type(cx, 0, true));
llargument_tys.push(arg.layout.scalar_pair_element_llvm_type(cx, 1, true));
continue;
}
PassMode::Indirect { attrs: _, meta_attrs: Some(_), on_stack: _ } => {
// Construct the type of a (wide) pointer to `ty`, and pass its two fields.
// Any two ABI-compatible unsized types have the same metadata type and
// moreover the same metadata value leads to the same dynamic size and
// alignment, so this respects ABI compatibility.
let ptr_ty = Ty::new_mut_ptr(cx.tcx, arg.layout.ty);
let ptr_layout = cx.layout_of(ptr_ty);
llargument_tys.push(ptr_layout.scalar_pair_element_llvm_type(cx, 0, true));
llargument_tys.push(ptr_layout.scalar_pair_element_llvm_type(cx, 1, true));
continue;
}
PassMode::Indirect { attrs: _, meta_attrs: None, on_stack: _ } => cx.type_ptr(),
PassMode::Cast { cast, pad_i32 } => {
// add padding
if *pad_i32 {
llargument_tys.push(Reg::i32().llvm_type(cx));
}
// Compute the LLVM type we use for this function from the cast type.
// We assume here that ABI-compatible Rust types have the same cast type.
cast.llvm_type(cx)
}
};
llargument_tys.push(llarg_ty);
}
if self.c_variadic {
cx.type_variadic_func(&llargument_tys, llreturn_ty)
} else {
cx.type_func(&llargument_tys, llreturn_ty)
}
}
fn ptr_to_llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
cx.type_ptr_ext(cx.data_layout().instruction_address_space)
}
fn llvm_cconv(&self) -> llvm::CallConv {
self.conv.into()
}
fn apply_attrs_llfn(&self, cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value) {
let mut func_attrs = SmallVec::<[_; 3]>::new();
if self.ret.layout.abi.is_uninhabited() {
func_attrs.push(llvm::AttributeKind::NoReturn.create_attr(cx.llcx));
}
if !self.can_unwind {
func_attrs.push(llvm::AttributeKind::NoUnwind.create_attr(cx.llcx));
}
if let Conv::RiscvInterrupt { kind } = self.conv {
func_attrs.push(llvm::CreateAttrStringValue(cx.llcx, "interrupt", kind.as_str()));
}
attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &{ func_attrs });
let mut i = 0;
let mut apply = |attrs: &ArgAttributes| {
attrs.apply_attrs_to_llfn(llvm::AttributePlace::Argument(i), cx, llfn);
i += 1;
i - 1
};
match &self.ret.mode {
PassMode::Direct(attrs) => {
attrs.apply_attrs_to_llfn(llvm::AttributePlace::ReturnValue, cx, llfn);
}
PassMode::Indirect { attrs, meta_attrs: _, on_stack } => {
assert!(!on_stack);
let i = apply(attrs);
let sret = llvm::CreateStructRetAttr(
cx.llcx,
cx.type_array(cx.type_i8(), self.ret.layout.size.bytes()),
);
attributes::apply_to_llfn(llfn, llvm::AttributePlace::Argument(i), &[sret]);
}
PassMode::Cast { cast, pad_i32: _ } => {
cast.attrs.apply_attrs_to_llfn(llvm::AttributePlace::ReturnValue, cx, llfn);
}
_ => {}
}
for arg in self.args.iter() {
match &arg.mode {
PassMode::Ignore => {}
PassMode::Indirect { attrs, meta_attrs: None, on_stack: true } => {
let i = apply(attrs);
let byval = llvm::CreateByValAttr(
cx.llcx,
cx.type_array(cx.type_i8(), arg.layout.size.bytes()),
);
attributes::apply_to_llfn(llfn, llvm::AttributePlace::Argument(i), &[byval]);
}
PassMode::Direct(attrs)
| PassMode::Indirect { attrs, meta_attrs: None, on_stack: false } => {
apply(attrs);
}
PassMode::Indirect { attrs, meta_attrs: Some(meta_attrs), on_stack } => {
assert!(!on_stack);
apply(attrs);
apply(meta_attrs);
}
PassMode::Pair(a, b) => {
apply(a);
apply(b);
}
PassMode::Cast { cast, pad_i32 } => {
if *pad_i32 {
apply(&ArgAttributes::new());
}
apply(&cast.attrs);
}
}
}
}
fn apply_attrs_callsite(&self, bx: &mut Builder<'_, 'll, 'tcx>, callsite: &'ll Value) {
let mut func_attrs = SmallVec::<[_; 2]>::new();
if self.ret.layout.abi.is_uninhabited() {
func_attrs.push(llvm::AttributeKind::NoReturn.create_attr(bx.cx.llcx));
}
if !self.can_unwind {
func_attrs.push(llvm::AttributeKind::NoUnwind.create_attr(bx.cx.llcx));
}
attributes::apply_to_callsite(callsite, llvm::AttributePlace::Function, &{ func_attrs });
let mut i = 0;
let mut apply = |cx: &CodegenCx<'_, '_>, attrs: &ArgAttributes| {
attrs.apply_attrs_to_callsite(llvm::AttributePlace::Argument(i), cx, callsite);
i += 1;
i - 1
};
match &self.ret.mode {
PassMode::Direct(attrs) => {
attrs.apply_attrs_to_callsite(llvm::AttributePlace::ReturnValue, bx.cx, callsite);
}
PassMode::Indirect { attrs, meta_attrs: _, on_stack } => {
assert!(!on_stack);
let i = apply(bx.cx, attrs);
let sret = llvm::CreateStructRetAttr(
bx.cx.llcx,
bx.cx.type_array(bx.cx.type_i8(), self.ret.layout.size.bytes()),
);
attributes::apply_to_callsite(callsite, llvm::AttributePlace::Argument(i), &[sret]);
}
PassMode::Cast { cast, pad_i32: _ } => {
cast.attrs.apply_attrs_to_callsite(
llvm::AttributePlace::ReturnValue,
bx.cx,
callsite,
);
}
_ => {}
}
if let abi::Abi::Scalar(scalar) = self.ret.layout.abi {
// If the value is a boolean, the range is 0..2 and that ultimately
// become 0..0 when the type becomes i1, which would be rejected
// by the LLVM verifier.
if let Int(..) = scalar.primitive() {
if !scalar.is_bool() && !scalar.is_always_valid(bx) {
bx.range_metadata(callsite, scalar.valid_range(bx));
}
}
}
for arg in self.args.iter() {
match &arg.mode {
PassMode::Ignore => {}
PassMode::Indirect { attrs, meta_attrs: None, on_stack: true } => {
let i = apply(bx.cx, attrs);
let byval = llvm::CreateByValAttr(
bx.cx.llcx,
bx.cx.type_array(bx.cx.type_i8(), arg.layout.size.bytes()),
);
attributes::apply_to_callsite(
callsite,
llvm::AttributePlace::Argument(i),
&[byval],
);
}
PassMode::Direct(attrs)
| PassMode::Indirect { attrs, meta_attrs: None, on_stack: false } => {
apply(bx.cx, attrs);
}
PassMode::Indirect { attrs, meta_attrs: Some(meta_attrs), on_stack: _ } => {
apply(bx.cx, attrs);
apply(bx.cx, meta_attrs);
}
PassMode::Pair(a, b) => {
apply(bx.cx, a);
apply(bx.cx, b);
}
PassMode::Cast { cast, pad_i32 } => {
if *pad_i32 {
apply(bx.cx, &ArgAttributes::new());
}
apply(bx.cx, &cast.attrs);
}
}
}
let cconv = self.llvm_cconv();
if cconv != llvm::CCallConv {
llvm::SetInstructionCallConv(callsite, cconv);
}
if self.conv == Conv::CCmseNonSecureCall {
// This will probably get ignored on all targets but those supporting the TrustZone-M
// extension (thumbv8m targets).
let cmse_nonsecure_call = llvm::CreateAttrString(bx.cx.llcx, "cmse_nonsecure_call");
attributes::apply_to_callsite(
callsite,
llvm::AttributePlace::Function,
&[cmse_nonsecure_call],
);
}
// Some intrinsics require that an elementtype attribute (with the pointee type of a
// pointer argument) is added to the callsite.
let element_type_index = unsafe { llvm::LLVMRustGetElementTypeArgIndex(callsite) };
if element_type_index >= 0 {
let arg_ty = self.args[element_type_index as usize].layout.ty;
let pointee_ty = arg_ty.builtin_deref(true).expect("Must be pointer argument").ty;
let element_type_attr = unsafe {
llvm::LLVMRustCreateElementTypeAttr(bx.llcx, bx.layout_of(pointee_ty).llvm_type(bx))
};
attributes::apply_to_callsite(
callsite,
llvm::AttributePlace::Argument(element_type_index as u32),
&[element_type_attr],
);
}
}
}
impl<'tcx> AbiBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
fn get_param(&mut self, index: usize) -> Self::Value {
llvm::get_param(self.llfn(), index as c_uint)
}
}
impl From<Conv> for llvm::CallConv {
fn from(conv: Conv) -> Self {
match conv {
Conv::C | Conv::Rust | Conv::CCmseNonSecureCall | Conv::RiscvInterrupt { .. } => {
llvm::CCallConv
}
Conv::Cold => llvm::ColdCallConv,
Conv::PreserveMost => llvm::PreserveMost,
Conv::PreserveAll => llvm::PreserveAll,
Conv::AvrInterrupt => llvm::AvrInterrupt,
Conv::AvrNonBlockingInterrupt => llvm::AvrNonBlockingInterrupt,
Conv::ArmAapcs => llvm::ArmAapcsCallConv,
Conv::Msp430Intr => llvm::Msp430Intr,
Conv::PtxKernel => llvm::PtxKernel,
Conv::X86Fastcall => llvm::X86FastcallCallConv,
Conv::X86Intr => llvm::X86_Intr,
Conv::X86Stdcall => llvm::X86StdcallCallConv,
Conv::X86ThisCall => llvm::X86_ThisCall,
Conv::X86VectorCall => llvm::X86_VectorCall,
Conv::X86_64SysV => llvm::X86_64_SysV,
Conv::X86_64Win64 => llvm::X86_64_Win64,
}
}
}