rust/src/attributes.rs

141 lines
4.9 KiB
Rust

#[cfg(feature = "master")]
use gccjit::FnAttribute;
use gccjit::Function;
#[cfg(feature = "master")]
use rustc_attr::InlineAttr;
use rustc_attr::InstructionSetAttr;
#[cfg(feature = "master")]
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use rustc_middle::ty;
use rustc_span::symbol::sym;
use crate::context::CodegenCx;
use crate::errors::TiedTargetFeatures;
use crate::gcc_util::{check_tied_features, to_gcc_features};
/// Get GCC attribute for the provided inline heuristic.
#[cfg(feature = "master")]
#[inline]
fn inline_attr<'gcc, 'tcx>(
cx: &CodegenCx<'gcc, 'tcx>,
inline: InlineAttr,
) -> Option<FnAttribute<'gcc>> {
match inline {
InlineAttr::Hint => Some(FnAttribute::Inline),
InlineAttr::Always => Some(FnAttribute::AlwaysInline),
InlineAttr::Never => {
if cx.sess().target.arch != "amdgpu" {
Some(FnAttribute::NoInline)
} else {
None
}
}
InlineAttr::None => None,
}
}
/// Composite function which sets GCC attributes for function depending on its AST (`#[attribute]`)
/// attributes.
pub fn from_fn_attrs<'gcc, 'tcx>(
cx: &CodegenCx<'gcc, 'tcx>,
#[cfg_attr(not(feature = "master"), allow(unused_variables))] func: Function<'gcc>,
instance: ty::Instance<'tcx>,
) {
let codegen_fn_attrs = cx.tcx.codegen_fn_attrs(instance.def_id());
#[cfg(feature = "master")]
{
let inline = if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
InlineAttr::Never
} else if codegen_fn_attrs.inline == InlineAttr::None
&& instance.def.requires_inline(cx.tcx)
{
InlineAttr::Hint
} else {
codegen_fn_attrs.inline
};
if let Some(attr) = inline_attr(cx, inline) {
if let FnAttribute::AlwaysInline = attr {
func.add_attribute(FnAttribute::Inline);
}
func.add_attribute(attr);
}
if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::COLD) {
func.add_attribute(FnAttribute::Cold);
}
if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::FFI_PURE) {
func.add_attribute(FnAttribute::Pure);
}
if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::FFI_CONST) {
func.add_attribute(FnAttribute::Const);
}
}
let function_features = codegen_fn_attrs
.target_features
.iter()
.map(|features| features.name.as_str())
.collect::<Vec<&str>>();
if let Some(features) = check_tied_features(
cx.tcx.sess,
&function_features.iter().map(|features| (*features, true)).collect(),
) {
let span = cx
.tcx
.get_attr(instance.def_id(), sym::target_feature)
.map_or_else(|| cx.tcx.def_span(instance.def_id()), |a| a.span);
cx.tcx.dcx().create_err(TiedTargetFeatures { features: features.join(", "), span }).emit();
return;
}
let mut function_features = function_features
.iter()
.flat_map(|feat| to_gcc_features(cx.tcx.sess, feat).into_iter())
.chain(codegen_fn_attrs.instruction_set.iter().map(|x| match *x {
InstructionSetAttr::ArmA32 => "-thumb-mode", // TODO(antoyo): support removing feature.
InstructionSetAttr::ArmT32 => "thumb-mode",
}))
.collect::<Vec<_>>();
// TODO(antoyo): cg_llvm adds global features to each function so that LTO keep them.
// Check if GCC requires the same.
let mut global_features = cx.tcx.global_backend_features(()).iter().map(|s| s.as_str());
function_features.extend(&mut global_features);
let target_features = function_features
.iter()
.filter_map(|feature| {
// FIXME(antoyo): for some reasons, disabling SSE results in the following error when
// compiling Rust for Linux:
// SSE register return with SSE disabled
// TODO(antoyo): support soft-float and retpoline-external-thunk.
if feature.contains("soft-float")
|| feature.contains("retpoline-external-thunk")
|| *feature == "-sse"
{
return None;
}
if feature.starts_with('-') {
Some(format!("no{}", feature))
} else if let Some(stripped) = feature.strip_prefix('+') {
Some(stripped.to_string())
} else {
Some(feature.to_string())
}
})
.collect::<Vec<_>>()
.join(",");
if !target_features.is_empty() {
#[cfg(feature = "master")]
match cx.sess().target.arch.as_ref() {
"x86" | "x86_64" | "powerpc" => {
func.add_attribute(FnAttribute::Target(&target_features))
}
// The target attribute is not supported on other targets in GCC.
_ => (),
}
}
}