Auto merge of rust-lang#95697 - klensy:no-strings, r=petrochenkov

refactor: simplify few string related interactions

Few small optimizations:

check_doc_keyword: don't alloc string for emptiness check
check_doc_alias_value: get argument as Symbol to prevent needless string convertions
check_doc_attrs: don't alloc vec, iterate over slice.
replace as_str() check with symbol check
get_single_str_from_tts: don't prealloc string
trivial string to str replace
LifetimeScopeForPath::NonElided use Vec<Symbol> instead of Vec<String>
AssertModuleSource use FxHashSet<Symbol> instead of BTreeSet<String>
CrateInfo.crate_name replace FxHashMap<CrateNum, String> with FxHashMap<CrateNum, Symbol>

Author: bors

compiler/rustc_builtin_macros/src/compile_error.rs

@@ -13,7 +13,7 @@ pub fn expand_compile_error<'cx>(
         return DummyResult::any(sp);
     };
 
-    cx.span_err(sp, &var);
+    cx.span_err(sp, var.as_str());
 
     DummyResult::any(sp)
 }

compiler/rustc_builtin_macros/src/env.rs

@@ -21,8 +21,8 @@ pub fn expand_option_env<'cx>(
     };
 
     let sp = cx.with_def_site_ctxt(sp);
-    let value = env::var(&var.as_str()).ok().as_deref().map(Symbol::intern);
-    cx.sess.parse_sess.env_depinfo.borrow_mut().insert((Symbol::intern(&var), value));
+    let value = env::var(var.as_str()).ok().as_deref().map(Symbol::intern);
+    cx.sess.parse_sess.env_depinfo.borrow_mut().insert((var, value));
     let e = match value {
         None => {
             let lt = cx.lifetime(sp, Ident::new(kw::StaticLifetime, sp));

compiler/rustc_builtin_macros/src/source_util.rs

@@ -104,7 +104,7 @@ pub fn expand_include<'cx>(
         return DummyResult::any(sp);
     };
     // The file will be added to the code map by the parser
-    let file = match resolve_path(cx, file, sp) {
+    let file = match resolve_path(cx, file.as_str(), sp) {
         Ok(f) => f,
         Err(mut err) => {
             err.emit();
@@ -176,7 +176,7 @@ pub fn expand_include_str(
     let Some(file) = get_single_str_from_tts(cx, sp, tts, "include_str!") else {
         return DummyResult::any(sp);
     };
-    let file = match resolve_path(cx, file, sp) {
+    let file = match resolve_path(cx, file.as_str(), sp) {
         Ok(f) => f,
         Err(mut err) => {
             err.emit();
@@ -210,7 +210,7 @@ pub fn expand_include_bytes(
     let Some(file) = get_single_str_from_tts(cx, sp, tts, "include_bytes!") else {
         return DummyResult::any(sp);
     };
-    let file = match resolve_path(cx, file, sp) {
+    let file = match resolve_path(cx, file.as_str(), sp) {
         Ok(f) => f,
         Err(mut err) => {
             err.emit();

compiler/rustc_codegen_cranelift/src/driver/jit.rs

@@ -288,8 +288,8 @@ fn load_imported_symbols_for_jit(
         match data[cnum.as_usize() - 1] {
             Linkage::NotLinked | Linkage::IncludedFromDylib => {}
             Linkage::Static => {
-                let name = &crate_info.crate_name[&cnum];
-                let mut err = sess.struct_err(&format!("Can't load static lib {}", name.as_str()));
+                let name = crate_info.crate_name[&cnum];
+                let mut err = sess.struct_err(&format!("Can't load static lib {}", name));
                 err.note("rustc_codegen_cranelift can only load dylibs in JIT mode.");
                 err.emit();
             }

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -216,7 +216,7 @@ pub fn each_linked_rlib(
             Some(_) => {}
             None => return Err("could not find formats for rlibs".to_string()),
         }
-        let name = &info.crate_name[&cnum];
+        let name = info.crate_name[&cnum];
         let used_crate_source = &info.used_crate_source[&cnum];
         if let Some((path, _)) = &used_crate_source.rlib {
             f(cnum, &path);
@@ -467,7 +467,7 @@ fn link_staticlib<'a, B: ArchiveBuilder<'a>>(
     let mut all_native_libs = vec![];
 
     let res = each_linked_rlib(&codegen_results.crate_info, &mut |cnum, path| {
-        let name = &codegen_results.crate_info.crate_name[&cnum];
+        let name = codegen_results.crate_info.crate_name[&cnum];
         let native_libs = &codegen_results.crate_info.native_libraries[&cnum];
 
         // Here when we include the rlib into our staticlib we need to make a

compiler/rustc_codegen_ssa/src/base.rs

@@ -861,7 +861,7 @@ impl CrateInfo {
         for &cnum in crates.iter() {
             info.native_libraries
                 .insert(cnum, tcx.native_libraries(cnum).iter().map(Into::into).collect());
-            info.crate_name.insert(cnum, tcx.crate_name(cnum).to_string());
+            info.crate_name.insert(cnum, tcx.crate_name(cnum));
             info.used_crate_source.insert(cnum, tcx.used_crate_source(cnum).clone());
             if tcx.is_compiler_builtins(cnum) {
                 info.compiler_builtins = Some(cnum);

compiler/rustc_codegen_ssa/src/lib.rs

@@ -146,7 +146,7 @@ pub struct CrateInfo {
     pub profiler_runtime: Option<CrateNum>,
     pub is_no_builtins: FxHashSet<CrateNum>,
     pub native_libraries: FxHashMap<CrateNum, Vec<NativeLib>>,
-    pub crate_name: FxHashMap<CrateNum, String>,
+    pub crate_name: FxHashMap<CrateNum, Symbol>,
     pub used_libraries: Vec<NativeLib>,
     pub used_crate_source: FxHashMap<CrateNum, Lrc<CrateSource>>,
     pub used_crates: Vec<CrateNum>,

compiler/rustc_expand/src/base.rs

@@ -1221,7 +1221,7 @@ pub fn get_single_str_from_tts(
     sp: Span,
     tts: TokenStream,
     name: &str,
-) -> Option<String> {
+) -> Option<Symbol> {
     let mut p = cx.new_parser_from_tts(tts);
     if p.token == token::Eof {
         cx.span_err(sp, &format!("{} takes 1 argument", name));
@@ -1233,7 +1233,7 @@ pub fn get_single_str_from_tts(
     if p.token != token::Eof {
         cx.span_err(sp, &format!("{} takes 1 argument", name));
     }
-    expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| s.to_string())
+    expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| s)
 }
 
 /// Extracts comma-separated expressions from `tts`.

compiler/rustc_incremental/src/assert_module_sources.rs

@@ -22,12 +22,12 @@
 //! was re-used.
 
 use rustc_ast as ast;
+use rustc_data_structures::stable_set::FxHashSet;
 use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_middle::mir::mono::CodegenUnitNameBuilder;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::cgu_reuse_tracker::*;
 use rustc_span::symbol::{sym, Symbol};
-use std::collections::BTreeSet;
 
 #[allow(missing_docs)]
 pub fn assert_module_sources(tcx: TyCtxt<'_>) {
@@ -36,12 +36,8 @@ pub fn assert_module_sources(tcx: TyCtxt<'_>) {
             return;
         }
 
-        let available_cgus = tcx
-            .collect_and_partition_mono_items(())
-            .1
-            .iter()
-            .map(|cgu| cgu.name().to_string())
-            .collect::<BTreeSet<String>>();
+        let available_cgus =
+            tcx.collect_and_partition_mono_items(()).1.iter().map(|cgu| cgu.name()).collect();
 
         let ams = AssertModuleSource { tcx, available_cgus };
 
@@ -53,7 +49,7 @@ pub fn assert_module_sources(tcx: TyCtxt<'_>) {
 
 struct AssertModuleSource<'tcx> {
     tcx: TyCtxt<'tcx>,
-    available_cgus: BTreeSet<String>,
+    available_cgus: FxHashSet<Symbol>,
 }
 
 impl<'tcx> AssertModuleSource<'tcx> {
@@ -124,18 +120,17 @@ impl<'tcx> AssertModuleSource<'tcx> {
 
         debug!("mapping '{}' to cgu name '{}'", self.field(attr, sym::module), cgu_name);
 
-        if !self.available_cgus.contains(cgu_name.as_str()) {
+        if !self.available_cgus.contains(&cgu_name) {
+            let mut cgu_names: Vec<&str> =
+                self.available_cgus.iter().map(|cgu| cgu.as_str()).collect();
+            cgu_names.sort();
             self.tcx.sess.span_err(
                 attr.span,
                 &format!(
                     "no module named `{}` (mangled: {}). Available modules: {}",
                     user_path,
                     cgu_name,
-                    self.available_cgus
-                        .iter()
-                        .map(|cgu| cgu.to_string())
-                        .collect::<Vec<_>>()
-                        .join(", ")
+                    cgu_names.join(", ")
                 ),
             );
         }

compiler/rustc_middle/src/middle/resolve_lifetime.rs

@@ -6,6 +6,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::ItemLocalId;
 use rustc_macros::HashStable;
+use rustc_span::symbol::Symbol;
 
 #[derive(Clone, Copy, PartialEq, Eq, Hash, TyEncodable, TyDecodable, Debug, HashStable)]
 pub enum Region {
@@ -23,7 +24,7 @@ pub enum Region {
 pub enum LifetimeScopeForPath {
     // Contains all lifetime names that are in scope and could possibly be used in generics
     // arguments of path.
-    NonElided(Vec<String>),
+    NonElided(Vec<Symbol>),
 
     // Information that allows us to suggest args of the form `<'_>` in case
     // no generic arguments were provided for a path.