fortrangoingonforty/afs-ld / 86f5fa3

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Speed string table planning

Authored by espadonne
SHA
86f5fa3b080aaf62b882b22b15081a471ab4c778
Parents
23e8dad
Tree
f9dc1f0

3 changed files

StatusFile+-
M src/lib.rs 12 0
M src/string_table.rs 42 9
M tests/perf_baseline.rs 11 1
src/lib.rsmodified
@@ -215,6 +215,9 @@ pub struct LinkPhaseTimings {
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     pub synth_sections: Duration,
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     pub synth_linkedit_finalize: Duration,
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     pub synth_linkedit_symbol_plan: Duration,
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+    pub synth_linkedit_symbol_plan_locals: Duration,
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+    pub synth_linkedit_symbol_plan_globals: Duration,
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+    pub synth_linkedit_symbol_plan_strtab: Duration,
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     pub synth_linkedit_dyld_info: Duration,
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     pub synth_linkedit_metadata_tables: Duration,
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     pub synth_linkedit_code_signature: Duration,
@@ -666,6 +669,9 @@ impl Linker {
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         let mut linkedit = None;
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         let mut synth_linkedit_finalize = Duration::ZERO;
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         let mut synth_linkedit_symbol_plan = Duration::ZERO;
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+        let mut synth_linkedit_symbol_plan_locals = Duration::ZERO;
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+        let mut synth_linkedit_symbol_plan_globals = Duration::ZERO;
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+        let mut synth_linkedit_symbol_plan_strtab = Duration::ZERO;
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         let mut synth_linkedit_dyld_info = Duration::ZERO;
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         let mut synth_linkedit_metadata_tables = Duration::ZERO;
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         let mut synth_linkedit_code_signature = Duration::ZERO;
@@ -682,6 +688,9 @@ impl Linker {
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                 )?;
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             synth_linkedit_finalize += phase_started.elapsed();
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             synth_linkedit_symbol_plan += linkedit_timings.symbol_plan;
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+            synth_linkedit_symbol_plan_locals += linkedit_timings.symbol_plan_locals;
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+            synth_linkedit_symbol_plan_globals += linkedit_timings.symbol_plan_globals;
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+            synth_linkedit_symbol_plan_strtab += linkedit_timings.symbol_plan_strtab;
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             synth_linkedit_dyld_info += linkedit_timings.dyld_info;
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             synth_linkedit_metadata_tables += linkedit_timings.metadata_tables;
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             synth_linkedit_code_signature += linkedit_timings.code_signature;
@@ -703,6 +712,9 @@ impl Linker {
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         let linkedit = linkedit.expect("finalize loop always runs at least once");
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         phases.synth_linkedit_finalize = synth_linkedit_finalize;
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         phases.synth_linkedit_symbol_plan = synth_linkedit_symbol_plan;
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+        phases.synth_linkedit_symbol_plan_locals = synth_linkedit_symbol_plan_locals;
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+        phases.synth_linkedit_symbol_plan_globals = synth_linkedit_symbol_plan_globals;
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+        phases.synth_linkedit_symbol_plan_strtab = synth_linkedit_symbol_plan_strtab;
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         phases.synth_linkedit_dyld_info = synth_linkedit_dyld_info;
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         phases.synth_linkedit_metadata_tables = synth_linkedit_metadata_tables;
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         phases.synth_linkedit_code_signature = synth_linkedit_code_signature;
src/string_table.rsmodified
@@ -98,10 +98,17 @@ impl StringTable {
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 #[derive(Debug, Clone, Default, PartialEq, Eq)]
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 pub struct StringTableBuilder {
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-    roots: Vec<(String, u32)>,
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+    roots: Vec<RootString>,
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+    roots_by_last_byte: HashMap<u8, Vec<usize>>,
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     offsets: HashMap<String, u32>,
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 }
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+#[derive(Debug, Clone, PartialEq, Eq)]
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+struct RootString {
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+    name: String,
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+    offset: u32,
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+}
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+
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 impl StringTableBuilder {
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     pub fn new() -> Self {
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         Self::default()
@@ -125,7 +132,17 @@ impl StringTableBuilder {
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             let offset = raw.len() as u32;
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             raw.extend_from_slice(name.as_bytes());
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             raw.push(0);
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-            self.roots.push((name.clone(), offset));
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+            let root_index = self.roots.len();
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+            self.roots.push(RootString {
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+                name: name.clone(),
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+                offset,
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+            });
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+            if let Some(&last_byte) = name.as_bytes().last() {
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+                self.roots_by_last_byte
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+                    .entry(last_byte)
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+                    .or_default()
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+                    .push(root_index);
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+            }
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             self.offsets.insert(name, offset);
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         }
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@@ -136,13 +153,16 @@ impl StringTableBuilder {
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     }
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     fn find_suffix_offset(&self, name: &str) -> Option<u32> {
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-        self.roots.iter().find_map(|(existing, offset)| {
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-            if existing.ends_with(name) {
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-                Some(*offset + (existing.len() - name.len()) as u32)
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-            } else {
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-                None
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-            }
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-        })
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+        let last_byte = *name.as_bytes().last()?;
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+        self.roots_by_last_byte
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+            .get(&last_byte)?
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+            .iter()
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+            .find_map(|&idx| {
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+                let existing = &self.roots[idx];
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+                (existing.name.len() >= name.len() && existing.name.ends_with(name)).then(|| {
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+                    existing.offset + (existing.name.len() - name.len()) as u32
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+                })
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+            })
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     }
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 }
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@@ -253,4 +273,17 @@ mod tests {
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         assert_eq!(array, afs + 4);
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         assert_eq!(table.as_bytes().len() % 8, 0);
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     }
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+
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+    #[test]
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+    fn builder_ignores_same_last_byte_non_suffix_names() {
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+        let mut builder = StringTableBuilder::new();
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+        builder.insert("_alpha");
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+        builder.insert("_beta");
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+
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+        let (bytes, offsets) = builder.finish();
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+        let table = StringTable::from_bytes(bytes);
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+
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+        assert_eq!(table.get(offsets["_alpha"]).unwrap(), "_alpha");
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+        assert_eq!(table.get(offsets["_beta"]).unwrap(), "_beta");
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+    }
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 }
tests/perf_baseline.rsmodified
@@ -39,7 +39,7 @@ fn executable_opts(inputs: Vec<PathBuf>, output: PathBuf) -> LinkOptions {
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 fn assert_profile_basics(name: &str, profile: &LinkProfile) {
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     eprintln!(
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-        "{name}: total={:?} parse={:?} resolve={:?} atomize={:?} layout={:?} synth={:?} (linkedit={:?}: symbols={:?} dyld={:?} metadata={:?} codesig={:?}; unwind={:?}) reloc={:?} write={:?}",
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+        "{name}: total={:?} parse={:?} resolve={:?} atomize={:?} layout={:?} synth={:?} (linkedit={:?}: symbols={:?} [locals={:?} globals={:?} strtab={:?}] dyld={:?} metadata={:?} codesig={:?}; unwind={:?}) reloc={:?} write={:?}",
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         profile.total_wall,
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         profile.phases.input_parsing,
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         profile.phases.symbol_resolution,
@@ -48,6 +48,9 @@ fn assert_profile_basics(name: &str, profile: &LinkProfile) {
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         profile.phases.synth_sections,
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         profile.phases.synth_linkedit_finalize,
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         profile.phases.synth_linkedit_symbol_plan,
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+        profile.phases.synth_linkedit_symbol_plan_locals,
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+        profile.phases.synth_linkedit_symbol_plan_globals,
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+        profile.phases.synth_linkedit_symbol_plan_strtab,
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         profile.phases.synth_linkedit_dyld_info,
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         profile.phases.synth_linkedit_metadata_tables,
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         profile.phases.synth_linkedit_code_signature,
@@ -77,6 +80,13 @@ fn assert_profile_basics(name: &str, profile: &LinkProfile) {
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                 + profile.phases.synth_linkedit_code_signature,
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         "{name}: linkedit subphases exceeded linkedit total"
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     );
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+    assert!(
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+        profile.phases.synth_linkedit_symbol_plan
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+            >= profile.phases.synth_linkedit_symbol_plan_locals
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+                + profile.phases.synth_linkedit_symbol_plan_globals
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+                + profile.phases.synth_linkedit_symbol_plan_strtab,
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+        "{name}: symbol-plan subphases exceeded symbol-plan total"
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+    );
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 }
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 #[test]