433 lines
15 KiB
Rust
433 lines
15 KiB
Rust
use std::mem;
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use crate::deriving;
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use syntax::ast::{self, Ident};
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use syntax::attr;
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use syntax::source_map::{ExpnInfo, MacroAttribute, hygiene, respan};
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use syntax::ext::base::ExtCtxt;
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use syntax::ext::build::AstBuilder;
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use syntax::ext::expand::ExpansionConfig;
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use syntax::ext::hygiene::Mark;
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use syntax::mut_visit::MutVisitor;
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use syntax::parse::ParseSess;
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use syntax::ptr::P;
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use syntax::symbol::Symbol;
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use syntax::symbol::keywords;
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use syntax::visit::{self, Visitor};
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use syntax_pos::{Span, DUMMY_SP};
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const PROC_MACRO_KINDS: [&str; 3] = ["proc_macro_derive", "proc_macro_attribute", "proc_macro"];
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struct ProcMacroDerive {
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trait_name: ast::Name,
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function_name: Ident,
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span: Span,
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attrs: Vec<ast::Name>,
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}
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struct ProcMacroDef {
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function_name: Ident,
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span: Span,
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}
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struct CollectProcMacros<'a> {
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derives: Vec<ProcMacroDerive>,
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attr_macros: Vec<ProcMacroDef>,
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bang_macros: Vec<ProcMacroDef>,
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in_root: bool,
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handler: &'a errors::Handler,
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is_proc_macro_crate: bool,
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is_test_crate: bool,
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}
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pub fn modify(sess: &ParseSess,
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resolver: &mut dyn (::syntax::ext::base::Resolver),
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mut krate: ast::Crate,
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is_proc_macro_crate: bool,
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has_proc_macro_decls: bool,
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is_test_crate: bool,
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num_crate_types: usize,
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handler: &errors::Handler) -> ast::Crate {
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let ecfg = ExpansionConfig::default("proc_macro".to_string());
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let mut cx = ExtCtxt::new(sess, ecfg, resolver);
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let (derives, attr_macros, bang_macros) = {
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let mut collect = CollectProcMacros {
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derives: Vec::new(),
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attr_macros: Vec::new(),
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bang_macros: Vec::new(),
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in_root: true,
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handler,
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is_proc_macro_crate,
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is_test_crate,
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};
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if has_proc_macro_decls || is_proc_macro_crate {
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visit::walk_crate(&mut collect, &krate);
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}
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(collect.derives, collect.attr_macros, collect.bang_macros)
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};
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if !is_proc_macro_crate {
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return krate
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}
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if num_crate_types > 1 {
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handler.err("cannot mix `proc-macro` crate type with others");
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}
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if is_test_crate {
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return krate;
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}
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krate.module.items.push(mk_decls(&mut cx, &derives, &attr_macros, &bang_macros));
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krate
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}
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pub fn is_proc_macro_attr(attr: &ast::Attribute) -> bool {
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PROC_MACRO_KINDS.iter().any(|kind| attr.check_name(kind))
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}
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impl<'a> CollectProcMacros<'a> {
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fn check_not_pub_in_root(&self, vis: &ast::Visibility, sp: Span) {
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if self.is_proc_macro_crate && self.in_root && vis.node.is_pub() {
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self.handler.span_err(sp,
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"`proc-macro` crate types cannot \
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export any items other than functions \
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tagged with `#[proc_macro_derive]` currently");
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}
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}
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fn collect_custom_derive(&mut self, item: &'a ast::Item, attr: &'a ast::Attribute) {
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// Once we've located the `#[proc_macro_derive]` attribute, verify
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// that it's of the form `#[proc_macro_derive(Foo)]` or
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// `#[proc_macro_derive(Foo, attributes(A, ..))]`
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let list = match attr.meta_item_list() {
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Some(list) => list,
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None => return,
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};
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if list.len() != 1 && list.len() != 2 {
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self.handler.span_err(attr.span,
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"attribute must have either one or two arguments");
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return
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}
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let trait_attr = match list[0].meta_item() {
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Some(meta_item) => meta_item,
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_ => {
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self.handler.span_err(list[0].span(), "not a meta item");
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return
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}
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};
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let trait_ident = match trait_attr.ident() {
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Some(trait_ident) if trait_attr.is_word() => trait_ident,
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_ => {
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self.handler.span_err(trait_attr.span, "must only be one word");
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return
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}
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};
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if !trait_ident.can_be_raw() {
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self.handler.span_err(trait_attr.span,
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&format!("`{}` cannot be a name of derive macro", trait_ident));
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}
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if deriving::is_builtin_trait(trait_ident.name) {
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self.handler.span_err(trait_attr.span,
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"cannot override a built-in derive macro");
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}
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let attributes_attr = list.get(1);
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let proc_attrs: Vec<_> = if let Some(attr) = attributes_attr {
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if !attr.check_name("attributes") {
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self.handler.span_err(attr.span(), "second argument must be `attributes`")
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}
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attr.meta_item_list().unwrap_or_else(|| {
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self.handler.span_err(attr.span(),
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"attribute must be of form: `attributes(foo, bar)`");
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&[]
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}).into_iter().filter_map(|attr| {
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let attr = match attr.meta_item() {
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Some(meta_item) => meta_item,
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_ => {
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self.handler.span_err(attr.span(), "not a meta item");
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return None;
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}
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};
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let ident = match attr.ident() {
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Some(ident) if attr.is_word() => ident,
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_ => {
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self.handler.span_err(attr.span, "must only be one word");
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return None;
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}
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};
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if !ident.can_be_raw() {
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self.handler.span_err(
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attr.span,
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&format!("`{}` cannot be a name of derive helper attribute", ident),
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);
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}
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Some(ident.name)
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}).collect()
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} else {
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Vec::new()
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};
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if self.in_root && item.vis.node.is_pub() {
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self.derives.push(ProcMacroDerive {
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span: item.span,
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trait_name: trait_ident.name,
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function_name: item.ident,
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attrs: proc_attrs,
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});
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} else {
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let msg = if !self.in_root {
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"functions tagged with `#[proc_macro_derive]` must \
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currently reside in the root of the crate"
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} else {
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"functions tagged with `#[proc_macro_derive]` must be `pub`"
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};
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self.handler.span_err(item.span, msg);
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}
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}
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fn collect_attr_proc_macro(&mut self, item: &'a ast::Item) {
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if self.in_root && item.vis.node.is_pub() {
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self.attr_macros.push(ProcMacroDef {
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span: item.span,
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function_name: item.ident,
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});
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} else {
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let msg = if !self.in_root {
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"functions tagged with `#[proc_macro_attribute]` must \
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currently reside in the root of the crate"
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} else {
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"functions tagged with `#[proc_macro_attribute]` must be `pub`"
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};
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self.handler.span_err(item.span, msg);
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}
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}
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fn collect_bang_proc_macro(&mut self, item: &'a ast::Item) {
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if self.in_root && item.vis.node.is_pub() {
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self.bang_macros.push(ProcMacroDef {
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span: item.span,
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function_name: item.ident,
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});
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} else {
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let msg = if !self.in_root {
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"functions tagged with `#[proc_macro]` must \
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currently reside in the root of the crate"
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} else {
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"functions tagged with `#[proc_macro]` must be `pub`"
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};
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self.handler.span_err(item.span, msg);
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}
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}
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}
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impl<'a> Visitor<'a> for CollectProcMacros<'a> {
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fn visit_item(&mut self, item: &'a ast::Item) {
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if let ast::ItemKind::MacroDef(..) = item.node {
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if self.is_proc_macro_crate && attr::contains_name(&item.attrs, "macro_export") {
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let msg =
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"cannot export macro_rules! macros from a `proc-macro` crate type currently";
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self.handler.span_err(item.span, msg);
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}
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}
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// First up, make sure we're checking a bare function. If we're not then
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// we're just not interested in this item.
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//
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// If we find one, try to locate a `#[proc_macro_derive]` attribute on
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// it.
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let is_fn = match item.node {
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ast::ItemKind::Fn(..) => true,
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_ => false,
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};
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let mut found_attr: Option<&'a ast::Attribute> = None;
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for attr in &item.attrs {
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if is_proc_macro_attr(&attr) {
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if let Some(prev_attr) = found_attr {
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let msg = if attr.path.segments[0].ident.name ==
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prev_attr.path.segments[0].ident.name {
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format!("Only one `#[{}]` attribute is allowed on any given function",
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attr.path)
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} else {
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format!("`#[{}]` and `#[{}]` attributes cannot both be applied \
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to the same function", attr.path, prev_attr.path)
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};
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self.handler.struct_span_err(attr.span, &msg)
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.span_note(prev_attr.span, "Previous attribute here")
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.emit();
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return;
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}
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found_attr = Some(attr);
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}
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}
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let attr = match found_attr {
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None => {
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self.check_not_pub_in_root(&item.vis, item.span);
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let prev_in_root = mem::replace(&mut self.in_root, false);
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visit::walk_item(self, item);
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self.in_root = prev_in_root;
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return;
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},
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Some(attr) => attr,
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};
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if !is_fn {
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let msg = format!("the `#[{}]` attribute may only be used on bare functions",
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attr.path);
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self.handler.span_err(attr.span, &msg);
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return;
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}
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if self.is_test_crate {
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return;
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}
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if !self.is_proc_macro_crate {
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let msg = format!("the `#[{}]` attribute is only usable with crates of the \
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`proc-macro` crate type", attr.path);
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self.handler.span_err(attr.span, &msg);
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return;
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}
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if attr.check_name("proc_macro_derive") {
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self.collect_custom_derive(item, attr);
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} else if attr.check_name("proc_macro_attribute") {
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self.collect_attr_proc_macro(item);
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} else if attr.check_name("proc_macro") {
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self.collect_bang_proc_macro(item);
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};
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let prev_in_root = mem::replace(&mut self.in_root, false);
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visit::walk_item(self, item);
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self.in_root = prev_in_root;
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}
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fn visit_mac(&mut self, mac: &ast::Mac) {
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visit::walk_mac(self, mac)
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}
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}
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// Creates a new module which looks like:
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//
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// mod $gensym {
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// extern crate proc_macro;
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//
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// use proc_macro::bridge::client::ProcMacro;
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//
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// #[rustc_proc_macro_decls]
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// static DECLS: &[ProcMacro] = &[
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// ProcMacro::custom_derive($name_trait1, &[], ::$name1);
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// ProcMacro::custom_derive($name_trait2, &["attribute_name"], ::$name2);
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// // ...
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// ];
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// }
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fn mk_decls(
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cx: &mut ExtCtxt<'_>,
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custom_derives: &[ProcMacroDerive],
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custom_attrs: &[ProcMacroDef],
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custom_macros: &[ProcMacroDef],
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) -> P<ast::Item> {
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let mark = Mark::fresh(Mark::root());
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mark.set_expn_info(ExpnInfo {
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call_site: DUMMY_SP,
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def_site: None,
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format: MacroAttribute(Symbol::intern("proc_macro")),
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allow_internal_unstable: Some(vec![
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Symbol::intern("rustc_attrs"),
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Symbol::intern("proc_macro_internals"),
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].into()),
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allow_internal_unsafe: false,
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local_inner_macros: false,
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edition: hygiene::default_edition(),
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});
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let span = DUMMY_SP.apply_mark(mark);
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let proc_macro = Ident::from_str("proc_macro");
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let krate = cx.item(span,
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proc_macro,
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Vec::new(),
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ast::ItemKind::ExternCrate(None));
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let bridge = Ident::from_str("bridge");
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let client = Ident::from_str("client");
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let proc_macro_ty = Ident::from_str("ProcMacro");
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let custom_derive = Ident::from_str("custom_derive");
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let attr = Ident::from_str("attr");
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let bang = Ident::from_str("bang");
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let crate_kw = Ident::with_empty_ctxt(keywords::Crate.name());
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let decls = {
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let local_path = |sp: Span, name| {
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cx.expr_path(cx.path(sp.with_ctxt(span.ctxt()), vec![crate_kw, name]))
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};
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let proc_macro_ty_method_path = |method| cx.expr_path(cx.path(span, vec![
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proc_macro, bridge, client, proc_macro_ty, method,
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]));
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custom_derives.iter().map(|cd| {
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cx.expr_call(span, proc_macro_ty_method_path(custom_derive), vec![
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cx.expr_str(cd.span, cd.trait_name),
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cx.expr_vec_slice(
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span,
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cd.attrs.iter().map(|&s| cx.expr_str(cd.span, s)).collect::<Vec<_>>()
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),
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local_path(cd.span, cd.function_name),
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])
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}).chain(custom_attrs.iter().map(|ca| {
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cx.expr_call(span, proc_macro_ty_method_path(attr), vec![
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cx.expr_str(ca.span, ca.function_name.name),
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local_path(ca.span, ca.function_name),
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])
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})).chain(custom_macros.iter().map(|cm| {
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cx.expr_call(span, proc_macro_ty_method_path(bang), vec![
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cx.expr_str(cm.span, cm.function_name.name),
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local_path(cm.span, cm.function_name),
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])
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})).collect()
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};
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let decls_static = cx.item_static(
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span,
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Ident::from_str("_DECLS"),
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cx.ty_rptr(span,
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cx.ty(span, ast::TyKind::Slice(
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cx.ty_path(cx.path(span,
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vec![proc_macro, bridge, client, proc_macro_ty])))),
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None, ast::Mutability::Immutable),
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ast::Mutability::Immutable,
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cx.expr_vec_slice(span, decls),
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).map(|mut i| {
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let attr = cx.meta_word(span, Symbol::intern("rustc_proc_macro_decls"));
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i.attrs.push(cx.attribute(span, attr));
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i.vis = respan(span, ast::VisibilityKind::Public);
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i
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});
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let module = cx.item_mod(
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span,
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span,
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ast::Ident::with_empty_ctxt(Symbol::gensym("decls")),
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vec![],
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vec![krate, decls_static],
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).map(|mut i| {
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i.vis = respan(span, ast::VisibilityKind::Public);
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i
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});
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cx.monotonic_expander().flat_map_item(module).pop().unwrap()
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}
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