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|
#[cfg(feature="master")]
use gccjit::FnAttribute;
use gccjit::Function;
use rustc_attr::InstructionSetAttr;
#[cfg(feature="master")]
use rustc_attr::InlineAttr;
use rustc_middle::ty;
#[cfg(feature="master")]
use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use rustc_span::symbol::sym;
use crate::{context::CodegenCx, 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_RETURNS_TWICE) {
func.add_attribute(FnAttribute::ReturnsTwice);
}
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.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.sess.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 feature.starts_with('+') {
Some(feature[1..].to_string())
}
else {
Some(feature.to_string())
}
})
.collect::<Vec<_>>()
.join(",");
if !target_features.is_empty() {
#[cfg(feature="master")]
func.add_attribute(FnAttribute::Target(&target_features));
}
}
|
