5 use syntax::ast::{self, Ident};
7 use syntax::source_map::{ExpnInfo, MacroAttribute, hygiene, respan};
8 use syntax::ext::base::ExtCtxt;
9 use syntax::ext::build::AstBuilder;
10 use syntax::ext::expand::ExpansionConfig;
11 use syntax::ext::hygiene::Mark;
12 use syntax::fold::Folder;
13 use syntax::parse::ParseSess;
15 use syntax::symbol::Symbol;
16 use syntax::symbol::keywords;
17 use syntax::visit::{self, Visitor};
19 use syntax_pos::{Span, DUMMY_SP};
23 const PROC_MACRO_KINDS: [&str; 3] = ["proc_macro_derive", "proc_macro_attribute", "proc_macro"];
25 struct ProcMacroDerive {
26 trait_name: ast::Name,
29 attrs: Vec<ast::Name>,
37 struct CollectProcMacros<'a> {
38 derives: Vec<ProcMacroDerive>,
39 attr_macros: Vec<ProcMacroDef>,
40 bang_macros: Vec<ProcMacroDef>,
42 handler: &'a errors::Handler,
43 is_proc_macro_crate: bool,
47 pub fn modify(sess: &ParseSess,
48 resolver: &mut dyn (::syntax::ext::base::Resolver),
49 mut krate: ast::Crate,
50 is_proc_macro_crate: bool,
51 has_proc_macro_decls: bool,
53 num_crate_types: usize,
54 handler: &errors::Handler) -> ast::Crate {
55 let ecfg = ExpansionConfig::default("proc_macro".to_string());
56 let mut cx = ExtCtxt::new(sess, ecfg, resolver);
58 let (derives, attr_macros, bang_macros) = {
59 let mut collect = CollectProcMacros {
61 attr_macros: Vec::new(),
62 bang_macros: Vec::new(),
68 if has_proc_macro_decls || is_proc_macro_crate {
69 visit::walk_crate(&mut collect, &krate);
71 (collect.derives, collect.attr_macros, collect.bang_macros)
74 if !is_proc_macro_crate {
78 if num_crate_types > 1 {
79 handler.err("cannot mix `proc-macro` crate type with others");
86 krate.module.items.push(mk_decls(&mut cx, &derives, &attr_macros, &bang_macros));
91 pub fn is_proc_macro_attr(attr: &ast::Attribute) -> bool {
92 PROC_MACRO_KINDS.iter().any(|kind| attr.check_name(kind))
95 impl<'a> CollectProcMacros<'a> {
96 fn check_not_pub_in_root(&self, vis: &ast::Visibility, sp: Span) {
97 if self.is_proc_macro_crate && self.in_root && vis.node.is_pub() {
98 self.handler.span_err(sp,
99 "`proc-macro` crate types cannot \
100 export any items other than functions \
101 tagged with `#[proc_macro_derive]` currently");
105 fn collect_custom_derive(&mut self, item: &'a ast::Item, attr: &'a ast::Attribute) {
106 // Once we've located the `#[proc_macro_derive]` attribute, verify
107 // that it's of the form `#[proc_macro_derive(Foo)]` or
108 // `#[proc_macro_derive(Foo, attributes(A, ..))]`
109 let list = match attr.meta_item_list() {
113 if list.len() != 1 && list.len() != 2 {
114 self.handler.span_err(attr.span(),
115 "attribute must have either one or two arguments");
118 let trait_attr = &list[0];
119 let attributes_attr = list.get(1);
120 let trait_name = match trait_attr.name() {
123 self.handler.span_err(trait_attr.span(), "not a meta item");
127 if !trait_attr.is_word() {
128 self.handler.span_err(trait_attr.span(), "must only be one word");
131 if deriving::is_builtin_trait(trait_name) {
132 self.handler.span_err(trait_attr.span(),
133 "cannot override a built-in #[derive] mode");
136 let proc_attrs: Vec<_> = if let Some(attr) = attributes_attr {
137 if !attr.check_name("attributes") {
138 self.handler.span_err(attr.span(), "second argument must be `attributes`")
140 attr.meta_item_list().unwrap_or_else(|| {
141 self.handler.span_err(attr.span(),
142 "attribute must be of form: \
143 `attributes(foo, bar)`");
145 }).into_iter().filter_map(|attr| {
146 let name = match attr.name() {
149 self.handler.span_err(attr.span(), "not a meta item");
155 self.handler.span_err(attr.span(), "must only be one word");
165 if self.in_root && item.vis.node.is_pub() {
166 self.derives.push(ProcMacroDerive {
169 function_name: item.ident,
173 let msg = if !self.in_root {
174 "functions tagged with `#[proc_macro_derive]` must \
175 currently reside in the root of the crate"
177 "functions tagged with `#[proc_macro_derive]` must be `pub`"
179 self.handler.span_err(item.span, msg);
183 fn collect_attr_proc_macro(&mut self, item: &'a ast::Item) {
184 if self.in_root && item.vis.node.is_pub() {
185 self.attr_macros.push(ProcMacroDef {
187 function_name: item.ident,
190 let msg = if !self.in_root {
191 "functions tagged with `#[proc_macro_attribute]` must \
192 currently reside in the root of the crate"
194 "functions tagged with `#[proc_macro_attribute]` must be `pub`"
196 self.handler.span_err(item.span, msg);
200 fn collect_bang_proc_macro(&mut self, item: &'a ast::Item) {
201 if self.in_root && item.vis.node.is_pub() {
202 self.bang_macros.push(ProcMacroDef {
204 function_name: item.ident,
207 let msg = if !self.in_root {
208 "functions tagged with `#[proc_macro]` must \
209 currently reside in the root of the crate"
211 "functions tagged with `#[proc_macro]` must be `pub`"
213 self.handler.span_err(item.span, msg);
218 impl<'a> Visitor<'a> for CollectProcMacros<'a> {
219 fn visit_item(&mut self, item: &'a ast::Item) {
220 if let ast::ItemKind::MacroDef(..) = item.node {
221 if self.is_proc_macro_crate && attr::contains_name(&item.attrs, "macro_export") {
223 "cannot export macro_rules! macros from a `proc-macro` crate type currently";
224 self.handler.span_err(item.span, msg);
228 // First up, make sure we're checking a bare function. If we're not then
229 // we're just not interested in this item.
231 // If we find one, try to locate a `#[proc_macro_derive]` attribute on
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("proc_macro_derive") {
295 self.collect_custom_derive(item, attr);
296 } else if attr.check_name("proc_macro_attribute") {
297 self.collect_attr_proc_macro(item);
298 } else if attr.check_name("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: &ast::Mac) {
308 visit::walk_mac(self, mac)
312 // Creates a new module which looks like:
315 // extern crate proc_macro;
317 // use proc_macro::bridge::client::ProcMacro;
319 // #[rustc_proc_macro_decls]
320 // static DECLS: &[ProcMacro] = &[
321 // ProcMacro::custom_derive($name_trait1, &[], ::$name1);
322 // ProcMacro::custom_derive($name_trait2, &["attribute_name"], ::$name2);
328 custom_derives: &[ProcMacroDerive],
329 custom_attrs: &[ProcMacroDef],
330 custom_macros: &[ProcMacroDef],
332 let mark = Mark::fresh(Mark::root());
333 mark.set_expn_info(ExpnInfo {
336 format: MacroAttribute(Symbol::intern("proc_macro")),
337 allow_internal_unstable: true,
338 allow_internal_unsafe: false,
339 local_inner_macros: false,
340 edition: hygiene::default_edition(),
342 let span = DUMMY_SP.apply_mark(mark);
344 let proc_macro = Ident::from_str("proc_macro");
345 let krate = cx.item(span,
348 ast::ItemKind::ExternCrate(None));
350 let bridge = Ident::from_str("bridge");
351 let client = Ident::from_str("client");
352 let proc_macro_ty = Ident::from_str("ProcMacro");
353 let custom_derive = Ident::from_str("custom_derive");
354 let attr = Ident::from_str("attr");
355 let bang = Ident::from_str("bang");
356 let crate_kw = Ident::with_empty_ctxt(keywords::Crate.name());
359 let local_path = |sp: Span, name| {
360 cx.expr_path(cx.path(sp.with_ctxt(span.ctxt()), vec![crate_kw, name]))
362 let proc_macro_ty_method_path = |method| cx.expr_path(cx.path(span, vec![
363 proc_macro, bridge, client, proc_macro_ty, method,
365 custom_derives.iter().map(|cd| {
366 cx.expr_call(span, proc_macro_ty_method_path(custom_derive), vec![
367 cx.expr_str(cd.span, cd.trait_name),
370 cd.attrs.iter().map(|&s| cx.expr_str(cd.span, s)).collect::<Vec<_>>()
372 local_path(cd.span, cd.function_name),
374 }).chain(custom_attrs.iter().map(|ca| {
375 cx.expr_call(span, proc_macro_ty_method_path(attr), vec![
376 cx.expr_str(ca.span, ca.function_name.name),
377 local_path(ca.span, ca.function_name),
379 })).chain(custom_macros.iter().map(|cm| {
380 cx.expr_call(span, proc_macro_ty_method_path(bang), vec![
381 cx.expr_str(cm.span, cm.function_name.name),
382 local_path(cm.span, cm.function_name),
387 let decls_static = cx.item_static(
389 Ident::from_str("_DECLS"),
391 cx.ty(span, ast::TyKind::Slice(
392 cx.ty_path(cx.path(span,
393 vec![proc_macro, bridge, client, proc_macro_ty])))),
394 None, ast::Mutability::Immutable),
395 ast::Mutability::Immutable,
396 cx.expr_vec_slice(span, decls),
398 let attr = cx.meta_word(span, Symbol::intern("rustc_proc_macro_decls"));
399 i.attrs.push(cx.attribute(span, attr));
400 i.vis = respan(span, ast::VisibilityKind::Public);
404 let module = cx.item_mod(
407 ast::Ident::with_empty_ctxt(Symbol::gensym("decls")),
409 vec![krate, decls_static],
411 i.vis = respan(span, ast::VisibilityKind::Public);
415 cx.monotonic_expander().fold_item(module).pop().unwrap()