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use proc_macro::TokenStream;
use proc_macro2::Span;
use quote::{quote_spanned, ToTokens};
use syn::{
parse::Parse, parse_macro_input, parse_quote, punctuated::Punctuated, spanned::Spanned, Error,
FnArg, Ident, ItemFn, ReturnType, Stmt, Token,
};
#[proc_macro_attribute]
pub fn kernel(input: proc_macro::TokenStream, item: proc_macro::TokenStream) -> TokenStream {
let cloned = input.clone();
let _ = parse_macro_input!(input as KernelHints);
let input = parse_macro_input!(cloned as proc_macro2::TokenStream);
let mut item = parse_macro_input!(item as ItemFn);
let no_mangle = parse_quote!(#[no_mangle]);
item.attrs.push(no_mangle);
let internal = parse_quote!(#[cfg_attr(any(target_arch="nvptx", target_arch="nvptx64"), nvvm_internal(kernel(#input)))]);
item.attrs.push(internal);
item.sig.abi = Some(parse_quote!(extern "C"));
let check_fn = parse_quote! {
fn assert_kernel_parameter_is_copy<T: Copy>() {}
};
item.block.stmts.insert(0, check_fn);
for param in &item.sig.inputs {
let ty = match param {
FnArg::Receiver(_) => quote_spanned! {
param.span() => ::core::compile_error!("Kernel functions may not be struct methods");
},
FnArg::Typed(ty) => ty.ty.to_token_stream(),
};
let call = parse_quote! {
assert_kernel_parameter_is_copy::<#ty>();
};
item.block.stmts.insert(0, call);
}
let ret = item.sig.output.clone();
if let ReturnType::Type(_, _) = ret {
let err = quote_spanned! {
ret.span() => ::core::compile_err!("Kernel functions should not return anything");
}
.into();
item.block.stmts.insert(0, parse_macro_input!(err as Stmt));
}
if item.sig.unsafety.is_none() {
let err = quote_spanned! {
item.span() => ::core::compile_error!("Kernel functions must be marked as unsafe");
}
.into();
item.block.stmts.insert(0, parse_macro_input!(err as Stmt));
}
item.to_token_stream().into()
}
#[derive(Debug, Clone, Copy, PartialEq)]
enum Dimension {
Dim1,
Dim2,
Dim3,
}
impl Parse for Dimension {
fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
let val = Ident::parse(input)?;
let val = val.to_string();
match val.as_str() {
"1d" | "1D" => Ok(Self::Dim1),
"2d" | "2D" => Ok(Self::Dim2),
"3d" | "3D" => Ok(Self::Dim3),
_ => Err(syn::Error::new(Span::call_site(), "Invalid dimension")),
}
}
}
enum KernelHint {
GridDim(Dimension),
BlockDim(Dimension),
}
impl Parse for KernelHint {
fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
let name = Ident::parse(input)?;
let key = name.to_string();
<Token![=]>::parse(input)?;
match key.as_str() {
"grid_dim" => {
let dim = Dimension::parse(input)?;
Ok(Self::GridDim(dim))
}
"block_dim" => {
let dim = Dimension::parse(input)?;
Ok(Self::BlockDim(dim))
}
_ => Err(Error::new(Span::call_site(), "Unrecognized option")),
}
}
}
#[derive(Debug, Default, Clone, PartialEq)]
struct KernelHints {
grid_dim: Option<Dimension>,
block_dim: Option<Dimension>,
}
impl Parse for KernelHints {
fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
let iter = Punctuated::<KernelHint, Token![,]>::parse_terminated(input)?;
let hints = iter
.into_pairs()
.map(|x| x.into_value())
.collect::<Vec<_>>();
let mut out = KernelHints::default();
for hint in hints {
match hint {
KernelHint::GridDim(dim) => out.grid_dim = Some(dim),
KernelHint::BlockDim(dim) => out.block_dim = Some(dim),
}
}
Ok(out)
}
}
#[proc_macro_attribute]
pub fn gpu_only(_attr: proc_macro::TokenStream, item: proc_macro::TokenStream) -> TokenStream {
let syn::ItemFn {
attrs,
vis,
sig,
block,
} = syn::parse_macro_input!(item as syn::ItemFn);
let mut cloned_attrs = attrs.clone();
cloned_attrs.retain(|a| {
!a.path
.get_ident()
.map(|x| *x == "nvvm_internal")
.unwrap_or_default()
});
let fn_name = sig.ident.clone();
let sig_cpu = syn::Signature {
abi: None,
..sig.clone()
};
let output = quote::quote! {
#[cfg(not(any(target_arch="nvptx", target_arch="nvptx64")))]
#[allow(unused_variables)]
#(#cloned_attrs)* #vis #sig_cpu {
unimplemented!(concat!("`", stringify!(#fn_name), "` can only be used on the GPU with rustc_codegen_nvvm"))
}
#[cfg(any(target_arch="nvptx", target_arch="nvptx64"))]
#(#attrs)* #vis #sig {
#block
}
};
output.into()
}
#[proc_macro_attribute]
pub fn externally_visible(
_attr: proc_macro::TokenStream,
item: proc_macro::TokenStream,
) -> TokenStream {
let mut func = syn::parse_macro_input!(item as syn::ItemFn);
assert!(
func.attrs.iter().any(|a| a.path.is_ident("no_mangle")),
"#[externally_visible] function should also be #[no_mangle]"
);
let new_attr = parse_quote!(#[cfg_attr(target_os = "cuda", nvvm_internal(used))]);
func.attrs.push(new_attr);
func.into_token_stream().into()
}
#[proc_macro_attribute]
pub fn address_space(attr: proc_macro::TokenStream, item: proc_macro::TokenStream) -> TokenStream {
let mut global = syn::parse_macro_input!(item as syn::ItemStatic);
let input = syn::parse_macro_input!(attr as Ident);
let addrspace_num = match input.to_string().as_str() {
"global" => 1,
"shared" => 3,
"constant" => 4,
"local" => 5,
addr => panic!("Invalid address space `{}`", addr),
};
let new_attr =
parse_quote!(#[cfg_attr(target_os = "cuda", nvvm_internal(addrspace(#addrspace_num)))]);
global.attrs.push(new_attr);
global.into_token_stream().into()
}