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extern crate cargo_metadata;
extern crate quote;
extern crate syn;
fn main() {
let out_dir = std::env::var_os("OUT_DIR").unwrap();
llvm::Generator::default()
.parse_llvm_sys_crate()
.expect("Unable to parse 'llvm-sys' crate")
.write_declarations(&std::path::PathBuf::from(out_dir).join("llvm_gen.rs"))
.expect("Unable to write generated LLVM declarations");
// Workaround for `cargo package`
// `cargo metadata` creates a new Cargo.lock file, which needs removing
let manifest_dir = std::env::var_os("CARGO_MANIFEST_DIR").unwrap();
let cargo_lock = std::path::PathBuf::from(manifest_dir).join("Cargo.lock");
if let Err(err) = std::fs::remove_file(&cargo_lock) {
if err.kind() != std::io::ErrorKind::NotFound {
panic!("failed to delete {}: {err}", cargo_lock.display());
}
}
}
mod llvm {
use anyhow::{format_err, Context as _, Error};
use cargo_metadata::{MetadataCommand, Package, Target};
use quote::{format_ident, quote};
use std::{
collections::{
hash_map::{Entry, HashMap},
HashSet,
},
fs, io, iter,
path::Path,
};
const INIT_MACROS: &[&str] = &[
"LLVM_InitializeAllTargetInfos",
"LLVM_InitializeAllTargets",
"LLVM_InitializeAllTargetMCs",
"LLVM_InitializeAllAsmPrinters",
"LLVM_InitializeAllAsmParsers",
"LLVM_InitializeAllDisassemblers",
"LLVM_InitializeNativeTarget",
"LLVM_InitializeNativeAsmParser",
"LLVM_InitializeNativeAsmPrinter",
"LLVM_InitializeNativeDisassembler",
];
#[derive(Default)]
pub struct Generator {
functions: HashMap<syn::Ident, (Vec<syn::Ident>, syn::ItemFn)>,
}
fn llvm_sys() -> syn::Ident {
format_ident!("llvm_sys")
}
impl Generator {
pub fn parse_llvm_sys_crate(&mut self) -> Result<&mut Self, Error> {
// See https://github.com/rust-lang/cargo/pull/12783.
#[rustversion::before(1.79)]
const LLVM_SYS_CRATE_TARGET: &str = "llvm-sys";
#[rustversion::since(1.79)]
const LLVM_SYS_CRATE_TARGET: &str = "llvm_sys";
let metadata = MetadataCommand::new()
.exec()
.context("Unable to get crate metadata")?;
let llvm_sys_src_path = metadata
.packages
.into_iter()
.find_map(|Package { name, targets, .. }| {
(name == "llvm-sys")
.then(|| {
targets
.into_iter()
.find_map(|Target { name, src_path, .. }| {
(name == LLVM_SYS_CRATE_TARGET).then_some(src_path)
})
})
.flatten()
})
.ok_or_else(|| format_err!("Unable to find 'llvm-sys' in the crate metadata"))?;
self.generate_file(llvm_sys_src_path.as_std_path(), &[llvm_sys()])?;
Ok(self)
}
pub fn generate_mod(
&mut self,
fs_path: &Path,
mod_path: &[syn::Ident],
m: syn::ItemMod,
) -> Result<(), Error> {
let syn::ItemMod { ident, content, .. } = m;
let directory = fs_path.join(ident.to_string());
let mod_path: Vec<_> = mod_path.iter().chain(iter::once(&ident)).cloned().collect();
match content {
None => {
// The module is in another file (or directory).
let fs_path = if directory
.try_exists()
.with_context(|| directory.display().to_string())?
{
directory.join("mod.rs")
} else {
directory.with_extension("rs")
};
self.generate_file(&fs_path, mod_path.as_slice())
.with_context(|| fs_path.display().to_string())
.map_err(Into::into)
}
Some((_, items)) => {
// The module is inline.
for item in items {
match item {
syn::Item::Mod(m) => {
self.generate_mod(&directory, mod_path.as_slice(), m)
.with_context(|| quote! { #(#mod_path)::* }.to_string())?;
}
syn::Item::Type(..) => {}
item => {
panic!("unexpected item {}", quote! { #item });
}
}
}
Ok(())
}
}
}
pub fn generate_file(
&mut self,
fs_path: &Path,
mod_path: &[syn::Ident],
) -> Result<(), Error> {
let content =
fs::read_to_string(fs_path).with_context(|| fs_path.display().to_string())?;
let syn::File {
shebang: _,
attrs: _,
items,
} = syn::parse_file(&content).context(content)?;
for item in items {
match item {
syn::Item::Mod(m) => {
let fs_path = fs_path.parent().unwrap();
self.generate_mod(fs_path, mod_path, m)?;
}
syn::Item::ForeignMod(syn::ItemForeignMod {
attrs: _,
unsafety: mod_unsafety,
abi: mod_abi,
items,
brace_token: _,
}) => {
for item in items {
match item {
syn::ForeignItem::Fn(syn::ForeignItemFn {
attrs: _,
mut sig,
vis,
semi_token: _,
}) => {
let syn::Signature {
constness: _,
asyncness: _,
unsafety,
abi,
fn_token,
ident,
generics: _,
paren_token,
inputs,
variadic,
output,
} = &mut sig;
if unsafety.is_none() {
*unsafety = mod_unsafety;
}
if abi.is_none() {
*abi = Some(mod_abi.clone());
}
if INIT_MACROS.iter().any(|macro_name| ident == macro_name) {
// Skip target initialization wrappers
// (see llvm-sys/wrappers/target.c)
continue;
}
let mut bare_inputs = syn::punctuated::Punctuated::new();
let mut input_names = Vec::new();
for input in inputs.iter_mut() {
match input {
syn::FnArg::Receiver(receiver) => {
panic!(
"unexpected receiver {}",
quote! { #receiver }
);
}
syn::FnArg::Typed(syn::PatType {
attrs,
ref mut pat,
colon_token: _,
ty,
}) => {
bare_inputs.push(syn::BareFnArg {
attrs: attrs.clone(),
name: None,
ty: (**ty).clone(),
});
match &mut **pat {
syn::Pat::Ident(syn::PatIdent {
ref mut ident,
..
}) => {
// error[E0530]: function parameters cannot shadow tuple variants
// |
// 9923 | pub fn LLVMGetErrorTypeId(Err: LLVMErrorRef) -> LLVMErrorTypeId {
// | ^^^ cannot be named the same as a tuple variant
if ident == "Err" {
*ident = format_ident!("Error");
}
input_names.push(ident.clone());
}
pat => {
panic!(
"unexpected pat {}",
quote! { #pat }
);
}
}
}
}
}
let variadic = variadic.as_ref().map(
|syn::Variadic {
attrs,
pat: _,
dots,
comma,
}| {
syn::BareVariadic {
attrs: attrs.clone(),
name: None,
dots: *dots,
comma: *comma,
}
},
);
let type_bare_fn = syn::TypeBareFn {
lifetimes: Default::default(),
unsafety: *unsafety,
abi: abi.clone(),
fn_token: *fn_token,
paren_token: *paren_token,
inputs: bare_inputs,
variadic,
output: output.clone(),
};
let block = quote! {
{
let entry = unsafe {
crate::proxy::SHARED_LIB.get::<#type_bare_fn>(
stringify!(#ident).as_bytes(),
)
}.expect(stringify!(#ident));
entry(#(#input_names),*)
}
};
let block = syn::parse2(block).unwrap();
let ident = ident.clone();
let item_fn = syn::ItemFn {
attrs: Vec::new(),
vis,
sig,
block,
};
let item_fn = syn::parse2(quote! {
#[no_mangle]
#item_fn
})
.unwrap();
let Self { functions } = self;
match functions.entry(ident) {
Entry::Occupied(entry) => {
if entry.key() == "LLVMAddInstructionCombiningPass" {
// TODO(https://reviews.llvm.org/D155402): Remove this when the declaration isn't duplicated.
continue;
}
let ident = entry.key();
let (other_mod_path, _) = entry.get();
let mod_path = quote! { #(#mod_path::)*#ident };
let other_mod_path =
quote! { #(#other_mod_path::)*#ident };
panic!(
"duplicate function `{}` `{}`",
mod_path, other_mod_path
);
}
Entry::Vacant(entry) => {
entry.insert((mod_path.into(), item_fn));
}
}
}
item => {
panic!("unexpected item {}", quote! { #item });
}
}
}
}
syn::Item::Const(..)
| syn::Item::Enum(..)
| syn::Item::ExternCrate(..)
| syn::Item::Macro(..)
| syn::Item::Struct(..)
| syn::Item::Type(..)
| syn::Item::Use(..) => {}
item => {
panic!("unexpected item {}", quote! { #item });
}
}
}
Ok(())
}
pub fn write_declarations(&self, path: &Path) -> io::Result<()> {
let Self { functions } = self;
let mut items = Vec::new();
let mut paths = HashSet::new();
let root = [llvm_sys()];
let prelude = [llvm_sys(), format_ident!("prelude")];
paths.insert(root.as_slice());
paths.insert(prelude.as_slice());
for (path, item_fn) in functions.values() {
let item_fn = syn::parse2(quote! {
#item_fn
})
.unwrap();
items.push(item_fn);
paths.insert(path);
}
let items = paths
.into_iter()
.map(|path| {
syn::parse2(quote! {
use #(#path::)**;
})
.unwrap()
})
.chain(items)
.collect();
let file = syn::File {
shebang: None,
attrs: Vec::new(),
items,
};
let formatted = prettyplease::unparse(&file);
fs::write(path, formatted)
}
}
}