expand: Pick cfgs and cfg_attrs one by one, like other attributes
This commit is contained in:
Vadim Petrochenkov
parent
d63a8d965e
commit
e87ce7ad74
7 changed files with 240 additions and 165 deletions
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@ -328,6 +328,10 @@ impl<'a> StripUnconfigured<'a> {
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});
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}
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fn process_cfg_attr(&self, attr: Attribute) -> Vec<Attribute> {
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if attr.has_name(sym::cfg_attr) { self.expand_cfg_attr(attr, true) } else { vec![attr] }
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}
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/// Parse and expand a single `cfg_attr` attribute into a list of attributes
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/// when the configuration predicate is true, or otherwise expand into an
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/// empty list of attributes.
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@ -335,11 +339,7 @@ impl<'a> StripUnconfigured<'a> {
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/// Gives a compiler warning when the `cfg_attr` contains no attributes and
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/// is in the original source file. Gives a compiler error if the syntax of
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/// the attribute is incorrect.
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fn process_cfg_attr(&self, attr: Attribute) -> Vec<Attribute> {
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if !attr.has_name(sym::cfg_attr) {
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return vec![attr];
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}
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crate fn expand_cfg_attr(&self, attr: Attribute, recursive: bool) -> Vec<Attribute> {
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let (cfg_predicate, expanded_attrs) =
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match rustc_parse::parse_cfg_attr(&attr, &self.sess.parse_sess) {
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None => return vec![],
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@ -348,95 +348,109 @@ impl<'a> StripUnconfigured<'a> {
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// Lint on zero attributes in source.
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if expanded_attrs.is_empty() {
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return vec![attr];
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self.sess.parse_sess.buffer_lint(
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rustc_lint_defs::builtin::UNUSED_ATTRIBUTES,
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attr.span,
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ast::CRATE_NODE_ID,
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"`#[cfg_attr]` does not expand to any attributes",
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);
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}
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if !attr::cfg_matches(&cfg_predicate, &self.sess.parse_sess, self.features) {
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return vec![];
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}
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// We call `process_cfg_attr` recursively in case there's a
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// `cfg_attr` inside of another `cfg_attr`. E.g.
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// `#[cfg_attr(false, cfg_attr(true, some_attr))]`.
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expanded_attrs
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.into_iter()
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.flat_map(|(item, span)| {
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let orig_tokens = attr.tokens().to_tokenstream();
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if recursive {
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// We call `process_cfg_attr` recursively in case there's a
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// `cfg_attr` inside of another `cfg_attr`. E.g.
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// `#[cfg_attr(false, cfg_attr(true, some_attr))]`.
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expanded_attrs
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.into_iter()
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.flat_map(|item| self.process_cfg_attr(self.expand_cfg_attr_item(&attr, item)))
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.collect()
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} else {
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expanded_attrs.into_iter().map(|item| self.expand_cfg_attr_item(&attr, item)).collect()
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}
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}
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// We are taking an attribute of the form `#[cfg_attr(pred, attr)]`
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// and producing an attribute of the form `#[attr]`. We
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// have captured tokens for `attr` itself, but we need to
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// synthesize tokens for the wrapper `#` and `[]`, which
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// we do below.
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fn expand_cfg_attr_item(
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&self,
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attr: &Attribute,
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(item, item_span): (ast::AttrItem, Span),
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) -> Attribute {
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let orig_tokens = attr.tokens().to_tokenstream();
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// Use the `#` in `#[cfg_attr(pred, attr)]` as the `#` token
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// for `attr` when we expand it to `#[attr]`
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let mut orig_trees = orig_tokens.trees();
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let pound_token = match orig_trees.next().unwrap() {
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TokenTree::Token(token @ Token { kind: TokenKind::Pound, .. }) => token,
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_ => panic!("Bad tokens for attribute {:?}", attr),
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};
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let pound_span = pound_token.span;
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// We are taking an attribute of the form `#[cfg_attr(pred, attr)]`
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// and producing an attribute of the form `#[attr]`. We
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// have captured tokens for `attr` itself, but we need to
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// synthesize tokens for the wrapper `#` and `[]`, which
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// we do below.
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let mut trees = vec![(AttrAnnotatedTokenTree::Token(pound_token), Spacing::Alone)];
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if attr.style == AttrStyle::Inner {
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// For inner attributes, we do the same thing for the `!` in `#![some_attr]`
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let bang_token = match orig_trees.next().unwrap() {
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TokenTree::Token(token @ Token { kind: TokenKind::Not, .. }) => token,
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_ => panic!("Bad tokens for attribute {:?}", attr),
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};
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trees.push((AttrAnnotatedTokenTree::Token(bang_token), Spacing::Alone));
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}
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// We don't really have a good span to use for the syntheized `[]`
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// in `#[attr]`, so just use the span of the `#` token.
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let bracket_group = AttrAnnotatedTokenTree::Delimited(
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DelimSpan::from_single(pound_span),
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DelimToken::Bracket,
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item.tokens
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.as_ref()
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.unwrap_or_else(|| panic!("Missing tokens for {:?}", item))
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.create_token_stream(),
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);
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trees.push((bracket_group, Spacing::Alone));
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let tokens = Some(LazyTokenStream::new(AttrAnnotatedTokenStream::new(trees)));
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let attr = attr::mk_attr_from_item(item, tokens, attr.style, span);
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if attr.has_name(sym::crate_type) {
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self.sess.parse_sess.buffer_lint(
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rustc_lint_defs::builtin::DEPRECATED_CFG_ATTR_CRATE_TYPE_NAME,
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attr.span,
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ast::CRATE_NODE_ID,
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"`crate_type` within an `#![cfg_attr] attribute is deprecated`",
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);
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}
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if attr.has_name(sym::crate_name) {
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self.sess.parse_sess.buffer_lint(
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rustc_lint_defs::builtin::DEPRECATED_CFG_ATTR_CRATE_TYPE_NAME,
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attr.span,
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ast::CRATE_NODE_ID,
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"`crate_name` within an `#![cfg_attr] attribute is deprecated`",
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);
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}
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self.process_cfg_attr(attr)
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})
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.collect()
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// Use the `#` in `#[cfg_attr(pred, attr)]` as the `#` token
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// for `attr` when we expand it to `#[attr]`
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let mut orig_trees = orig_tokens.trees();
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let pound_token = match orig_trees.next().unwrap() {
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TokenTree::Token(token @ Token { kind: TokenKind::Pound, .. }) => token,
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_ => panic!("Bad tokens for attribute {:?}", attr),
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};
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let pound_span = pound_token.span;
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let mut trees = vec![(AttrAnnotatedTokenTree::Token(pound_token), Spacing::Alone)];
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if attr.style == AttrStyle::Inner {
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// For inner attributes, we do the same thing for the `!` in `#![some_attr]`
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let bang_token = match orig_trees.next().unwrap() {
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TokenTree::Token(token @ Token { kind: TokenKind::Not, .. }) => token,
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_ => panic!("Bad tokens for attribute {:?}", attr),
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};
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trees.push((AttrAnnotatedTokenTree::Token(bang_token), Spacing::Alone));
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}
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// We don't really have a good span to use for the syntheized `[]`
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// in `#[attr]`, so just use the span of the `#` token.
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let bracket_group = AttrAnnotatedTokenTree::Delimited(
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DelimSpan::from_single(pound_span),
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DelimToken::Bracket,
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item.tokens
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.as_ref()
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.unwrap_or_else(|| panic!("Missing tokens for {:?}", item))
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.create_token_stream(),
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);
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trees.push((bracket_group, Spacing::Alone));
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let tokens = Some(LazyTokenStream::new(AttrAnnotatedTokenStream::new(trees)));
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let attr = attr::mk_attr_from_item(item, tokens, attr.style, item_span);
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if attr.has_name(sym::crate_type) {
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self.sess.parse_sess.buffer_lint(
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rustc_lint_defs::builtin::DEPRECATED_CFG_ATTR_CRATE_TYPE_NAME,
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attr.span,
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ast::CRATE_NODE_ID,
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"`crate_type` within an `#![cfg_attr] attribute is deprecated`",
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);
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}
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if attr.has_name(sym::crate_name) {
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self.sess.parse_sess.buffer_lint(
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rustc_lint_defs::builtin::DEPRECATED_CFG_ATTR_CRATE_TYPE_NAME,
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attr.span,
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ast::CRATE_NODE_ID,
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"`crate_name` within an `#![cfg_attr] attribute is deprecated`",
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);
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}
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attr
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}
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/// Determines if a node with the given attributes should be included in this configuration.
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fn in_cfg(&self, attrs: &[Attribute]) -> bool {
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attrs.iter().all(|attr| {
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if !is_cfg(attr) {
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attrs.iter().all(|attr| !is_cfg(attr) || self.cfg_true(attr))
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}
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crate fn cfg_true(&self, attr: &Attribute) -> bool {
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let meta_item = match validate_attr::parse_meta(&self.sess.parse_sess, attr) {
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Ok(meta_item) => meta_item,
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Err(mut err) => {
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err.emit();
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return true;
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}
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let meta_item = match validate_attr::parse_meta(&self.sess.parse_sess, attr) {
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Ok(meta_item) => meta_item,
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Err(mut err) => {
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err.emit();
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return true;
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}
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};
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parse_cfg(&meta_item, &self.sess).map_or(true, |meta_item| {
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attr::cfg_matches(&meta_item, &self.sess.parse_sess, self.features)
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})
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};
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parse_cfg(&meta_item, &self.sess).map_or(true, |meta_item| {
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attr::cfg_matches(&meta_item, &self.sess.parse_sess, self.features)
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})
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}
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