Improve, document and test symbol normalization

Author: Kobzol

collector/src/artifact_stats.rs

@@ -102,16 +102,41 @@ impl ArtifactStats {
     }
 }
 
-/// Tries to match hashes produces by rustc in mangled symbol names.
-static RUSTC_HASH_REGEX: OnceLock<Regex> = OnceLock::new();
-
 /// Demangle the symbol and remove rustc mangling hashes.
+///
+/// Normalizes the following things, in the following order:
+/// - Demangles the symbol.
+/// - Removes `.cold` and `.warm` from the end of the symbol, to merge cold and hot parts of a function
+/// into the same symbol.
+/// - Removes rustc hashes from the symbol, e.g. `foo::[abcdef]` -> `foo::[]` or
+/// `foo::abcd` -> `foo`.
+/// - Removes suffixes after a dot from the symbol, e.g. `anon.abcdef.123` -> `anon` or
+/// `foo.llvm.123` -> `foo`.
 fn normalize_symbol_name(symbol: &str) -> String {
-    let regex =
-        RUSTC_HASH_REGEX.get_or_init(|| Regex::new(r#"(::)?\b[a-z0-9]{15,17}\b(\.\d+)?"#).unwrap());
+    /// Tries to match hashes in brackets produces by rustc in mangled symbol names.
+    static RUSTC_BRACKET_HASH_REGEX: OnceLock<Regex> = OnceLock::new();
+    /// Tries to match hashes after :: produces by rustc in mangled symbol names.
+    static RUSTC_HASH_REGEX: OnceLock<Regex> = OnceLock::new();
+    /// Tries to match suffixes after a dot.
+    static DOT_SUFFIX_REGEX: OnceLock<Regex> = OnceLock::new();
+
+    let bracket_hash_regex =
+        RUSTC_BRACKET_HASH_REGEX.get_or_init(|| Regex::new(r#"\[[a-z0-9]{13,17}\]"#).unwrap());
+    let hash_regex = RUSTC_HASH_REGEX.get_or_init(|| Regex::new(r#"::[a-z0-9]{15,17}$"#).unwrap());
+    let dot_suffix_regex = DOT_SUFFIX_REGEX.get_or_init(|| Regex::new(r#"\.[a-z0-9]+\b"#).unwrap());
+
+    let mut symbol = rustc_demangle::demangle(symbol).to_string();
 
-    let symbol = rustc_demangle::demangle(symbol).to_string();
-    regex.replace_all(&symbol, "").to_string()
+    if let Some(stripped) = symbol.strip_suffix(".cold") {
+        symbol = stripped.to_string();
+    }
+    if let Some(stripped) = symbol.strip_suffix(".warm") {
+        symbol = stripped.to_string();
+    }
+    let symbol = bracket_hash_regex.replace_all(&symbol, "");
+    let symbol = hash_regex.replace_all(&symbol, "");
+    let symbol = dot_suffix_regex.replace_all(&symbol, "");
+    symbol.to_string()
 }
 
 /// Simple heuristic that tries to normalize section names.
@@ -229,3 +254,60 @@ pub fn compile_and_get_stats(
 
     Ok(archives)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn normalize_remove_cold_annotation() {
+        assert_eq!(
+            normalize_symbol_name("_RNvNtNtNtCs1WKcaCLTok2_16rustc_query_impl10query_impl23specialization_graph_of14get_query_incr26___rust_end_short_backtrace.cold"),
+            "rustc_query_impl::query_impl::specialization_graph_of::get_query_incr::__rust_end_short_backtrace".to_string()
+        );
+    }
+
+    #[test]
+    fn normalize_remove_numeric_suffix() {
+        assert_eq!(
+            normalize_symbol_name("_RNvMs3_NtNtCs6gyBaxODSsO_12regex_syntax3ast5parseINtB5_7ParserIQNtB5_6ParserE19parse_with_commentsB9_.llvm.5849848722809994645"),
+            "<regex_syntax::ast::parse::ParserI<&mut regex_syntax::ast::parse::Parser>>::parse_with_comments".to_string()
+        );
+    }
+
+    #[test]
+    fn normalize_remove_numeric_suffix_with_cold() {
+        assert_eq!(
+            normalize_symbol_name("_RNvMs_NtNtCs60zRYs2wPJS_11rustc_parse6parser2tyNtB6_6Parser15parse_ty_common.llvm.13047176952295404880.cold"),
+            "<rustc_parse::parser::Parser>::parse_ty_common".to_string()
+        );
+    }
+
+    #[test]
+    fn normalize_hash_at_end() {
+        assert_eq!(
+            normalize_symbol_name("anon.58936091071a36b1b82cf536b463328b.3488"),
+            "anon".to_string()
+        );
+    }
+
+    #[test]
+    fn normalize_short_hash() {
+        assert_eq!(
+            normalize_symbol_name(
+                "_RNvNtCsifRNxopDi_20rustc_builtin_macros6format16make_format_args"
+            ),
+            "rustc_builtin_macros::format::make_format_args".to_string()
+        );
+    }
+
+    #[test]
+    fn normalize_hash_without_brackets() {
+        assert_eq!(
+            normalize_symbol_name(
+                "_ZN10proc_macro5quote5quote28_$u7b$$u7b$closure$u7d$$u7d$17h90045007b0e69fc9E"
+            ),
+            "proc_macro::quote::quote::{{closure}}".to_string()
+        );
+    }
+}