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Avoid unnecessary MetaItem/Attribute conversions.

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`check_builtin_attribute` calls `parse_meta` to convert an `Attribute`
to a `MetaItem`, which it then checks. However, many callers of
`check_builtin_attribute` start with a `MetaItem`, and then convert it
to an `Attribute` by calling `cx.attribute(meta_item)`. This `MetaItem`
to `Attribute` to `MetaItem` conversion is silly.

This commit adds a new function `check_builtin_meta_item`, which can be
called instead from these call sites. `check_builtin_attribute` also now
calls it. The commit also renames `check_meta` as `check_attr` to better
match its arguments.
This commit is contained in:
Nicholas Nethercote 2022-11-24 16:00:57 +11:00
parent 2585bcea0b
commit c9ae38c71e
6 changed files with 44 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
compiler/rustc_ast_passes/src/ast_validation.rs
View File

@ -912,7 +912,7 @@ fn validate_generic_param_order(
impl<'a> Visitor<'a> for AstValidator<'a> {
fn visit_attribute(&mut self, attr: &Attribute) {
validate_attr::check_meta(&self.session.parse_sess, attr);
validate_attr::check_attr(&self.session.parse_sess, attr);
}
fn visit_expr(&mut self, expr: &'a Expr) {

6
compiler/rustc_builtin_macros/src/cfg_accessible.rs
View File

@ -37,10 +37,10 @@ impl MultiItemModifier for Expander {
_is_derive_const: bool,
) -> ExpandResult<Vec<Annotatable>, Annotatable> {
let template = AttributeTemplate { list: Some("path"), ..Default::default() };
let attr = &ecx.attribute(meta_item.clone());
validate_attr::check_builtin_attribute(
validate_attr::check_builtin_meta_item(
&ecx.sess.parse_sess,
attr,
&meta_item,
ast::AttrStyle::Outer,
sym::cfg_accessible,
template,
);

9
compiler/rustc_builtin_macros/src/derive.rs
View File

@ -33,14 +33,15 @@ impl MultiItemModifier for Expander {
ecx.resolver.resolve_derives(ecx.current_expansion.id, ecx.force_mode, &|| {
let template =
AttributeTemplate { list: Some("Trait1, Trait2, ..."), ..Default::default() };
let attr =
attr::mk_attr_outer(&sess.parse_sess.attr_id_generator, meta_item.clone());
validate_attr::check_builtin_attribute(
validate_attr::check_builtin_meta_item(
&sess.parse_sess,
&attr,
&meta_item,
ast::AttrStyle::Outer,
sym::derive,
template,
);
let attr =
attr::mk_attr_outer(&sess.parse_sess.attr_id_generator, meta_item.clone());
let mut resolutions: Vec<_> = attr
.meta_item_list()

11
compiler/rustc_builtin_macros/src/util.rs
View File

@ -1,4 +1,4 @@
use rustc_ast::{Attribute, MetaItem};
use rustc_ast::{AttrStyle, Attribute, MetaItem};
use rustc_expand::base::{Annotatable, ExtCtxt};
use rustc_feature::AttributeTemplate;
use rustc_lint_defs::builtin::DUPLICATE_MACRO_ATTRIBUTES;
@ -8,8 +8,13 @@ use rustc_span::Symbol;
pub fn check_builtin_macro_attribute(ecx: &ExtCtxt<'_>, meta_item: &MetaItem, name: Symbol) {
// All the built-in macro attributes are "words" at the moment.
let template = AttributeTemplate { word: true, ..Default::default() };
let attr = ecx.attribute(meta_item.clone());
validate_attr::check_builtin_attribute(&ecx.sess.parse_sess, &attr, name, template);
validate_attr::check_builtin_meta_item(
&ecx.sess.parse_sess,
&meta_item,
AttrStyle::Outer,
name,
template,
);
}
/// Emit a warning if the item is annotated with the given attribute. This is used to diagnose when

2
compiler/rustc_expand/src/expand.rs
View File

@ -1644,7 +1644,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
let mut span: Option<Span> = None;
while let Some(attr) = attrs.next() {
rustc_ast_passes::feature_gate::check_attribute(attr, self.cx.sess, features);
validate_attr::check_meta(&self.cx.sess.parse_sess, attr);
validate_attr::check_attr(&self.cx.sess.parse_sess, attr);
let current_span = if let Some(sp) = span { sp.to(attr.span) } else { attr.span };
span = Some(current_span);

43
compiler/rustc_parse/src/validate_attr.rs
View File

@ -10,9 +10,9 @@ use rustc_errors::{Applicability, FatalError, PResult};
use rustc_feature::{AttributeTemplate, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
use rustc_session::lint::builtin::ILL_FORMED_ATTRIBUTE_INPUT;
use rustc_session::parse::ParseSess;
use rustc_span::{sym, Symbol};
use rustc_span::{sym, Span, Symbol};
pub fn check_meta(sess: &ParseSess, attr: &Attribute) {
pub fn check_attr(sess: &ParseSess, attr: &Attribute) {
if attr.is_doc_comment() {
return;
}
@ -115,25 +115,34 @@ pub fn check_builtin_attribute(
name: Symbol,
template: AttributeTemplate,
) {
// Some special attributes like `cfg` must be checked
// before the generic check, so we skip them here.
let should_skip = |name| name == sym::cfg;
match parse_meta(sess, attr) {
Ok(meta) => {
if !should_skip(name) && !is_attr_template_compatible(&template, &meta.kind) {
emit_malformed_attribute(sess, attr, name, template);
}
}
Ok(meta) => check_builtin_meta_item(sess, &meta, attr.style, name, template),
Err(mut err) => {
err.emit();
}
}
}
pub fn check_builtin_meta_item(
sess: &ParseSess,
meta: &MetaItem,
style: ast::AttrStyle,
name: Symbol,
template: AttributeTemplate,
) {
// Some special attributes like `cfg` must be checked
// before the generic check, so we skip them here.
let should_skip = |name| name == sym::cfg;
if !should_skip(name) && !is_attr_template_compatible(&template, &meta.kind) {
emit_malformed_attribute(sess, style, meta.span, name, template);
}
}
fn emit_malformed_attribute(
sess: &ParseSess,
attr: &Attribute,
style: ast::AttrStyle,
span: Span,
name: Symbol,
template: AttributeTemplate,
) {
@ -147,7 +156,7 @@ fn emit_malformed_attribute(
let mut msg = "attribute must be of the form ".to_owned();
let mut suggestions = vec![];
let mut first = true;
let inner = if attr.style == ast::AttrStyle::Inner { "!" } else { "" };
let inner = if style == ast::AttrStyle::Inner { "!" } else { "" };
if template.word {
first = false;
let code = format!("#{}[{}]", inner, name);
@ -172,12 +181,12 @@ fn emit_malformed_attribute(
suggestions.push(code);
}
if should_warn(name) {
sess.buffer_lint(&ILL_FORMED_ATTRIBUTE_INPUT, attr.span, ast::CRATE_NODE_ID, &msg);
sess.buffer_lint(&ILL_FORMED_ATTRIBUTE_INPUT, span, ast::CRATE_NODE_ID, &msg);
} else {
sess.span_diagnostic
.struct_span_err(attr.span, &error_msg)
.struct_span_err(span, &error_msg)
.span_suggestions(
attr.span,
span,
if suggestions.len() == 1 {
"must be of the form"
} else {
@ -196,7 +205,7 @@ pub fn emit_fatal_malformed_builtin_attribute(
name: Symbol,
) -> ! {
let template = BUILTIN_ATTRIBUTE_MAP.get(&name).expect("builtin attr defined").template;
emit_malformed_attribute(sess, attr, name, template);
emit_malformed_attribute(sess, attr.style, attr.span, name, template);
// This is fatal, otherwise it will likely cause a cascade of other errors
// (and an error here is expected to be very rare).
FatalError.raise()