3 use syntax::ast::{self, Ident};
5 use syntax::source_map::{ExpnInfo, ExpnKind, respan};
6 use syntax::ext::base::{ExtCtxt, MacroKind};
7 use syntax::ext::build::AstBuilder;
8 use syntax::ext::expand::ExpansionConfig;
9 use syntax::ext::hygiene::ExpnId;
10 use syntax::ext::proc_macro::is_proc_macro_attr;
11 use syntax::mut_visit::MutVisitor;
12 use syntax::parse::ParseSess;
14 use syntax::symbol::{kw, sym};
15 use syntax::visit::{self, Visitor};
17 use syntax_pos::{Span, DUMMY_SP};
19 struct ProcMacroDerive {
20 trait_name: ast::Name,
23 attrs: Vec<ast::Name>,
31 struct CollectProcMacros<'a> {
32 derives: Vec<ProcMacroDerive>,
33 attr_macros: Vec<ProcMacroDef>,
34 bang_macros: Vec<ProcMacroDef>,
36 handler: &'a errors::Handler,
37 is_proc_macro_crate: bool,
41 pub fn inject(sess: &ParseSess,
42 resolver: &mut dyn (::syntax::ext::base::Resolver),
43 mut krate: ast::Crate,
44 is_proc_macro_crate: bool,
45 has_proc_macro_decls: bool,
47 num_crate_types: usize,
48 handler: &errors::Handler) -> ast::Crate {
49 let ecfg = ExpansionConfig::default("proc_macro".to_string());
50 let mut cx = ExtCtxt::new(sess, ecfg, resolver);
52 let (derives, attr_macros, bang_macros) = {
53 let mut collect = CollectProcMacros {
55 attr_macros: Vec::new(),
56 bang_macros: Vec::new(),
62 if has_proc_macro_decls || is_proc_macro_crate {
63 visit::walk_crate(&mut collect, &krate);
65 (collect.derives, collect.attr_macros, collect.bang_macros)
68 if !is_proc_macro_crate {
72 if num_crate_types > 1 {
73 handler.err("cannot mix `proc-macro` crate type with others");
80 krate.module.items.push(mk_decls(&mut cx, &derives, &attr_macros, &bang_macros));
85 impl<'a> CollectProcMacros<'a> {
86 fn check_not_pub_in_root(&self, vis: &ast::Visibility, sp: Span) {
87 if self.is_proc_macro_crate && self.in_root && vis.node.is_pub() {
88 self.handler.span_err(sp,
89 "`proc-macro` crate types cannot \
90 export any items other than functions \
91 tagged with `#[proc_macro_derive]` currently");
95 fn collect_custom_derive(&mut self, item: &'a ast::Item, attr: &'a ast::Attribute) {
96 // Once we've located the `#[proc_macro_derive]` attribute, verify
97 // that it's of the form `#[proc_macro_derive(Foo)]` or
98 // `#[proc_macro_derive(Foo, attributes(A, ..))]`
99 let list = match attr.meta_item_list() {
103 if list.len() != 1 && list.len() != 2 {
104 self.handler.span_err(attr.span,
105 "attribute must have either one or two arguments");
108 let trait_attr = match list[0].meta_item() {
109 Some(meta_item) => meta_item,
111 self.handler.span_err(list[0].span(), "not a meta item");
115 let trait_ident = match trait_attr.ident() {
116 Some(trait_ident) if trait_attr.is_word() => trait_ident,
118 self.handler.span_err(trait_attr.span, "must only be one word");
123 if !trait_ident.name.can_be_raw() {
124 self.handler.span_err(trait_attr.span,
125 &format!("`{}` cannot be a name of derive macro", trait_ident));
128 let attributes_attr = list.get(1);
129 let proc_attrs: Vec<_> = if let Some(attr) = attributes_attr {
130 if !attr.check_name(sym::attributes) {
131 self.handler.span_err(attr.span(), "second argument must be `attributes`")
133 attr.meta_item_list().unwrap_or_else(|| {
134 self.handler.span_err(attr.span(),
135 "attribute must be of form: `attributes(foo, bar)`");
137 }).into_iter().filter_map(|attr| {
138 let attr = match attr.meta_item() {
139 Some(meta_item) => meta_item,
141 self.handler.span_err(attr.span(), "not a meta item");
146 let ident = match attr.ident() {
147 Some(ident) if attr.is_word() => ident,
149 self.handler.span_err(attr.span, "must only be one word");
153 if !ident.name.can_be_raw() {
154 self.handler.span_err(
156 &format!("`{}` cannot be a name of derive helper attribute", ident),
166 if self.in_root && item.vis.node.is_pub() {
167 self.derives.push(ProcMacroDerive {
169 trait_name: trait_ident.name,
170 function_name: item.ident,
174 let msg = if !self.in_root {
175 "functions tagged with `#[proc_macro_derive]` must \
176 currently reside in the root of the crate"
178 "functions tagged with `#[proc_macro_derive]` must be `pub`"
180 self.handler.span_err(item.span, msg);
184 fn collect_attr_proc_macro(&mut self, item: &'a ast::Item) {
185 if self.in_root && item.vis.node.is_pub() {
186 self.attr_macros.push(ProcMacroDef {
188 function_name: item.ident,
191 let msg = if !self.in_root {
192 "functions tagged with `#[proc_macro_attribute]` must \
193 currently reside in the root of the crate"
195 "functions tagged with `#[proc_macro_attribute]` must be `pub`"
197 self.handler.span_err(item.span, msg);
201 fn collect_bang_proc_macro(&mut self, item: &'a ast::Item) {
202 if self.in_root && item.vis.node.is_pub() {
203 self.bang_macros.push(ProcMacroDef {
205 function_name: item.ident,
208 let msg = if !self.in_root {
209 "functions tagged with `#[proc_macro]` must \
210 currently reside in the root of the crate"
212 "functions tagged with `#[proc_macro]` must be `pub`"
214 self.handler.span_err(item.span, msg);
219 impl<'a> Visitor<'a> for CollectProcMacros<'a> {
220 fn visit_item(&mut self, item: &'a ast::Item) {
221 if let ast::ItemKind::MacroDef(..) = item.node {
222 if self.is_proc_macro_crate && attr::contains_name(&item.attrs, sym::macro_export) {
224 "cannot export macro_rules! macros from a `proc-macro` crate type currently";
225 self.handler.span_err(item.span, msg);
229 // First up, make sure we're checking a bare function. If we're not then
230 // we're just not interested in this item.
232 // If we find one, try to locate a `#[proc_macro_derive]` attribute on it.
233 let is_fn = match item.node {
234 ast::ItemKind::Fn(..) => true,
238 let mut found_attr: Option<&'a ast::Attribute> = None;
240 for attr in &item.attrs {
241 if is_proc_macro_attr(&attr) {
242 if let Some(prev_attr) = found_attr {
243 let msg = if attr.path.segments[0].ident.name ==
244 prev_attr.path.segments[0].ident.name {
245 format!("only one `#[{}]` attribute is allowed on any given function",
248 format!("`#[{}]` and `#[{}]` attributes cannot both be applied \
249 to the same function", attr.path, prev_attr.path)
252 self.handler.struct_span_err(attr.span, &msg)
253 .span_note(prev_attr.span, "previous attribute here")
259 found_attr = Some(attr);
263 let attr = match found_attr {
265 self.check_not_pub_in_root(&item.vis, item.span);
266 let prev_in_root = mem::replace(&mut self.in_root, false);
267 visit::walk_item(self, item);
268 self.in_root = prev_in_root;
275 let msg = format!("the `#[{}]` attribute may only be used on bare functions",
278 self.handler.span_err(attr.span, &msg);
282 if self.is_test_crate {
286 if !self.is_proc_macro_crate {
287 let msg = format!("the `#[{}]` attribute is only usable with crates of the \
288 `proc-macro` crate type", attr.path);
290 self.handler.span_err(attr.span, &msg);
294 if attr.check_name(sym::proc_macro_derive) {
295 self.collect_custom_derive(item, attr);
296 } else if attr.check_name(sym::proc_macro_attribute) {
297 self.collect_attr_proc_macro(item);
298 } else if attr.check_name(sym::proc_macro) {
299 self.collect_bang_proc_macro(item);
302 let prev_in_root = mem::replace(&mut self.in_root, false);
303 visit::walk_item(self, item);
304 self.in_root = prev_in_root;
307 fn visit_mac(&mut self, mac: &'a ast::Mac) {
308 visit::walk_mac(self, mac)
312 // Creates a new module which looks like:
316 // extern crate proc_macro;
318 // use proc_macro::bridge::client::ProcMacro;
320 // #[rustc_proc_macro_decls]
321 // static DECLS: &[ProcMacro] = &[
322 // ProcMacro::custom_derive($name_trait1, &[], ::$name1);
323 // ProcMacro::custom_derive($name_trait2, &["attribute_name"], ::$name2);
328 cx: &mut ExtCtxt<'_>,
329 custom_derives: &[ProcMacroDerive],
330 custom_attrs: &[ProcMacroDef],
331 custom_macros: &[ProcMacroDef],
333 let span = DUMMY_SP.fresh_expansion(ExpnId::root(), ExpnInfo::allow_unstable(
334 ExpnKind::Macro(MacroKind::Attr, sym::proc_macro), DUMMY_SP, cx.parse_sess.edition,
335 [sym::rustc_attrs, sym::proc_macro_internals][..].into(),
338 let hidden = cx.meta_list_item_word(span, sym::hidden);
339 let doc = cx.meta_list(span, sym::doc, vec![hidden]);
340 let doc_hidden = cx.attribute(span, doc);
342 let proc_macro = Ident::with_empty_ctxt(sym::proc_macro);
343 let krate = cx.item(span,
346 ast::ItemKind::ExternCrate(None));
348 let bridge = Ident::from_str("bridge");
349 let client = Ident::from_str("client");
350 let proc_macro_ty = Ident::from_str("ProcMacro");
351 let custom_derive = Ident::from_str("custom_derive");
352 let attr = Ident::from_str("attr");
353 let bang = Ident::from_str("bang");
354 let crate_kw = Ident::with_empty_ctxt(kw::Crate);
357 let local_path = |sp: Span, name| {
358 cx.expr_path(cx.path(sp.with_ctxt(span.ctxt()), vec![crate_kw, name]))
360 let proc_macro_ty_method_path = |method| cx.expr_path(cx.path(span, vec![
361 proc_macro, bridge, client, proc_macro_ty, method,
363 custom_derives.iter().map(|cd| {
364 cx.expr_call(span, proc_macro_ty_method_path(custom_derive), vec![
365 cx.expr_str(cd.span, cd.trait_name),
368 cd.attrs.iter().map(|&s| cx.expr_str(cd.span, s)).collect::<Vec<_>>()
370 local_path(cd.span, cd.function_name),
372 }).chain(custom_attrs.iter().map(|ca| {
373 cx.expr_call(span, proc_macro_ty_method_path(attr), vec![
374 cx.expr_str(ca.span, ca.function_name.name),
375 local_path(ca.span, ca.function_name),
377 })).chain(custom_macros.iter().map(|cm| {
378 cx.expr_call(span, proc_macro_ty_method_path(bang), vec![
379 cx.expr_str(cm.span, cm.function_name.name),
380 local_path(cm.span, cm.function_name),
385 let decls_static = cx.item_static(
387 Ident::from_str("_DECLS"),
389 cx.ty(span, ast::TyKind::Slice(
390 cx.ty_path(cx.path(span,
391 vec![proc_macro, bridge, client, proc_macro_ty])))),
392 None, ast::Mutability::Immutable),
393 ast::Mutability::Immutable,
394 cx.expr_vec_slice(span, decls),
396 let attr = cx.meta_word(span, sym::rustc_proc_macro_decls);
397 i.attrs.push(cx.attribute(span, attr));
398 i.vis = respan(span, ast::VisibilityKind::Public);
402 let module = cx.item_mod(
405 ast::Ident::from_str("decls").gensym(),
407 vec![krate, decls_static],
409 i.vis = respan(span, ast::VisibilityKind::Public);
413 cx.monotonic_expander().flat_map_item(module).pop().unwrap()