bjoernager/rust
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Auto merge of #60630 - nnethercote:use-Symbol-more, r=petrochenkov

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Use `Symbol` more

A `Symbol` can be equated with a string (e.g. `&str`). This involves a
TLS lookup to get the chars (and a Mutex lock in a parallel compiler)
and then a char-by-char comparison. This functionality is convenient but
avoids one of the main benefits of `Symbol`s, which is fast equality
comparisons.

This PR removes the `Symbol`/string equality operations, forcing a lot
of existing string occurrences to become `Symbol`s. Fortunately, these
are almost all static strings (many are attribute names) and we can add
static `Symbol`s as necessary, and very little extra interning occurs.
The benefits are (a) a slight speedup (possibly greater in a parallel
compiler), and (b) the code is a lot more principled about `Symbol` use.
The main downside is verbosity, particularly with more `use
syntax::symbol::symbols` items.

r? @Zoxc
This commit is contained in:
bors 2019-05-13 00:28:38 +00:00
commit fe5f42cdb8
135 changed files with 1507 additions and 1041 deletions
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8
src/libsyntax/parse/parser.rs
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@ -46,7 +46,7 @@ use crate::ptr::P;
use crate::parse::PResult;
use crate::ThinVec;
use crate::tokenstream::{self, DelimSpan, TokenTree, TokenStream, TreeAndJoint};
use crate::symbol::{keywords, Symbol};
use crate::symbol::{keywords, sym, Symbol};
use errors::{Applicability, DiagnosticBuilder, DiagnosticId, FatalError};
use rustc_target::spec::abi::{self, Abi};
@ -5084,7 +5084,7 @@ impl<'a> Parser<'a> {
(ident, ast::MacroDef { tokens: tokens.into(), legacy: false })
}
token::Ident(ident, _) if ident.name == "macro_rules" &&
token::Ident(ident, _) if ident.name == sym::macro_rules &&
self.look_ahead(1, |t| *t == token::Not) => {
let prev_span = self.prev_span;
self.complain_if_pub_macro(&vis.node, prev_span);
@ -7244,7 +7244,7 @@ impl<'a> Parser<'a> {
}
fn push_directory(&mut self, id: Ident, attrs: &[Attribute]) {
if let Some(path) = attr::first_attr_value_str_by_name(attrs, "path") {
if let Some(path) = attr::first_attr_value_str_by_name(attrs, sym::path) {
self.directory.path.to_mut().push(&path.as_str());
self.directory.ownership = DirectoryOwnership::Owned { relative: None };
} else {
@ -7264,7 +7264,7 @@ impl<'a> Parser<'a> {
}
pub fn submod_path_from_attr(attrs: &[Attribute], dir_path: &Path) -> Option<PathBuf> {
if let Some(s) = attr::first_attr_value_str_by_name(attrs, "path") {
if let Some(s) = attr::first_attr_value_str_by_name(attrs, sym::path) {
let s = s.as_str();
// On windows, the base path might have the form