Call an input section's contents, visit and kill by mold's names

InputSection read its bytes through data(), set its visited bit with
mark_visited and was marked dead with set_alive(false). mold's
InputSection has contents(), visit() and kill() for these; the
methods are named so here too, and the passes that drop a subsection
call kill(). set_alive stays for dead stripping, which sets the bit
to what its walk found.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

macho/chunks/output_section.rs

@@ -133,7 +133,7 @@ pub fn copy_buf<E: Target>(ctx: &Context<E>, id: OutputSectionId, buf: &mut [u8]
     // only ever write within their own subsection.
     for_each_member(ctx, osec, buf, |m, slice| {
         let isec = &ctx.isecs[m];
-        let data = isec.data();
+        let data = isec.contents();
         if data.is_empty() {
             return;
         }

macho/dead_strip.rs

@@ -163,7 +163,7 @@ fn collect_root_set<E: Target>(
     // the end.
     let mut enqueue = |id: usize, root: Root| {
         let id = redirects[id];
-        if ctx.isecs[id].mark_visited() {
+        if ctx.isecs[id].visit() {
             roots.push(id);
             if let Some(why) = why.as_deref_mut() {
                 why[id] = Why::Root(root);
@@ -260,7 +260,7 @@ pub fn native_refs_before_lto<E: Target>(
         for (msym, &id) in obj.mach_syms.iter().zip(&obj.symbols) {
             if msym.ty() == N_UNDF
                 && let Some(isec) = ctx.symbols[id].input_section()
-                && ctx.isecs[redirects[isec as usize]].mark_visited()
+                && ctx.isecs[redirects[isec as usize]].visit()
             {
                 roots.push(redirects[isec as usize]);
             }
@@ -370,7 +370,7 @@ fn visit_section<E: Target>(
     for_each_edge(ctx, id, |target| targets.push(target));
     for target in targets {
         let target = redirects[target];
-        if ctx.isecs[target].mark_visited() {
+        if ctx.isecs[target].visit() {
             if depth < 3 {
                 visit_section(ctx, redirects, target, depth + 1, next);
             } else {
@@ -429,7 +429,7 @@ fn walk<E: Target>(
     while let Some(id) = queue.pop_front() {
         for_each_edge(ctx, id, |target| {
             let target = redirects[target];
-            if ctx.isecs[target].mark_visited() {
+            if ctx.isecs[target].visit() {
                 if let Some(why) = why.as_deref_mut() {
                     why[target] = Why::From(id as u32);
                 }
@@ -466,7 +466,7 @@ fn mark_live_support<E: Target>(
             references_live |= ctx.isecs[redirects[target]].is_visited();
         });
         let id = redirects[id];
-        if references_live && ctx.isecs[id].mark_visited() {
+        if references_live && ctx.isecs[id].visit() {
             if let Some(why) = why.as_deref_mut() {
                 why[id] = Why::Root(Root::LiveSupport);
             }

macho/delay_init.rs

@@ -164,7 +164,7 @@ fn create_delay_helpers<E: Target>(
         let kind = match how {
             LazyRef::Cmp => DelayUse::Cmp,
             LazyRef::Load => {
-                let (reg, own) = E::lazy_load_site(ctx.isecs[isec as usize].data(), offset);
+                let (reg, own) = E::lazy_load_site(ctx.isecs[isec as usize].contents(), offset);
                 DelayUse::Load { reg, site: own.then_some((isec, offset)) }
             }
             _ => continue,

macho/icf.rs

@@ -415,8 +415,8 @@ fn compute_digest<E: Target>(ctx: &Context<E>, cand_index: &[usize], id: usize)
     let isec = &ctx.isecs[id];
     let mut h = SipHash13_128::new(&KEY);
     h.update(&isec.size.to_ne_bytes());
-    h.update(&isec.data().len().to_ne_bytes());
-    h.update(isec.data());
+    h.update(&isec.contents().len().to_ne_bytes());
+    h.update(isec.contents());
     for rel in isec.rels(&ctx.objs[isec.file as usize]) {
         h.update(&rel.offset.to_ne_bytes());
         h.update(&rel.ty.to_ne_bytes());
@@ -609,7 +609,7 @@ fn verify_leaders<E: Target>(
     let equal = |a: usize, b: usize| -> bool {
         let (x, y) = (&ctx.isecs[a], &ctx.isecs[b]);
         let (xr, yr) = (x.rels(&ctx.objs[x.file as usize]), y.rels(&ctx.objs[y.file as usize]));
-        x.data() == y.data()
+        x.contents() == y.contents()
             && xr.len() == yr.len()
             && xr.iter().zip(yr).all(|(r, s)| {
                 r.offset == s.offset

macho/input_sections.rs

@@ -231,7 +231,7 @@ pub struct InputSection {
     /// The subsection contents, as a bare pointer - the length is
     /// `size` - or 0 when there are none (a zero-fill or empty
     /// section). Stored as an integer, not a slice, to save 8 bytes and
-    /// keep the struct trivially Send/Sync; read through `data()`.
+    /// keep the struct trivially Send/Sync; read through `contents()`.
     /// mold likewise keeps `contents` as a bare address.
     pub contents: usize,
     /// This subsection's relocations: a range in the owning object's
@@ -410,9 +410,14 @@ impl InputSection {
             *f &= !IS_ALIVE;
         }
     }
+    /// Marks the subsection dead.
+    #[inline]
+    pub fn kill(&mut self) {
+        *self.flags.get_mut() &= !IS_ALIVE;
+    }
     /// Atomically sets the visited bit; true if this call set it.
     #[inline]
-    pub fn mark_visited(&self) -> bool {
+    pub fn visit(&self) -> bool {
         self.flags.fetch_or(IS_VISITED, std::sync::atomic::Ordering::Relaxed) & IS_VISITED == 0
     }
     /// Clears the visited bit, through a shared reference.
@@ -461,7 +466,7 @@ impl InputSection {
     /// otherwise the `size` bytes at `contents` (which point into the
     /// mmap'd input, so they live for the whole link).
     #[inline]
-    pub fn data(&self) -> &'static [u8] {
+    pub fn contents(&self) -> &'static [u8] {
         if self.contents == 0 {
             &[]
         } else {

macho/lazy_load.rs

@@ -90,7 +90,7 @@ pub(crate) fn import_uses<E: Target>(
         .filter(|&i| ctx.isecs[i].is_emitted())
         .flat_map_iter(|i| {
             let isec = &ctx.isecs[i];
-            let (file, data) = (&ctx.objs[isec.file as usize], isec.data());
+            let (file, data) = (&ctx.objs[isec.file as usize], isec.contents());
             isec.rels(file).iter().filter_map(move |r| {
                 let id = r.sym(file)?;
                 is_import(id).then(|| (i as u32, r.offset, id, E::lazy_ref(r, data)))
@@ -215,7 +215,7 @@ fn create_lazy_helpers<E: Target>(
             LazyRef::Call => LazyUse::Call,
             LazyRef::Cmp => LazyUse::Cmp,
             LazyRef::Load => {
-                let (reg, own) = E::lazy_load_site(ctx.isecs[isec as usize].data(), offset);
+                let (reg, own) = E::lazy_load_site(ctx.isecs[isec as usize].contents(), offset);
                 LazyUse::Load { reg, site: own.then_some((isec, offset)) }
             }
             LazyRef::Slot | LazyRef::Unsupported => continue,

macho/make_mergeable/mod.rs

@@ -426,7 +426,7 @@ impl<'a, E: Target> Builder<'a, E> {
                     Content::Image(out.fileoff + isec.offset as u64)
                 }
             }
-            _ => Content::Pool(isec.data()),
+            _ => Content::Pool(isec.contents()),
         }
     }
 
@@ -639,7 +639,7 @@ impl<'a, E: Target> Builder<'a, E> {
         let arm64 = E::CPUTYPE == CPU_TYPE_ARM64;
         let code = isec.hdr(&ctx.objs[obj]).flags & S_ATTR_SOME_INSTRUCTIONS != 0;
         let insn = |r: &Reloc| {
-            u32::from_le_bytes(isec.data()[r.offset as usize..][..4].try_into().unwrap())
+            u32::from_le_bytes(isec.contents()[r.offset as usize..][..4].try_into().unwrap())
         };
         // The other references to the slot in the subsection, after or
         // before this one.
@@ -774,7 +774,7 @@ impl<'a, E: Target> Builder<'a, E> {
                 continue;
             }
             let fixup = if E::CPUTYPE == CPU_TYPE_ARM64 {
-                arm64_fixup(isec.data(), r, target, addend)
+                arm64_fixup(isec.contents(), r, target, addend)
             } else {
                 x86_64_fixup(hdr, r, target, addend)
             };

macho/objc.rs

@@ -285,7 +285,7 @@ fn objc_class_ro<E: Target>(ctx: &Context<E>, cls: (u32, u64)) -> Option<(u32, u
 /// The C string a reference points at, if it is in the image.
 fn objc_cstring_at<E: Target>(ctx: &Context<E>, r: Option<ObjcRef>) -> Option<&'static [u8]> {
     let (isec, off) = objc_ref_location(ctx, r?)?;
-    let data = ctx.isecs[isec as usize].data();
+    let data = ctx.isecs[isec as usize].contents();
     let bytes = data.get(off as usize..)?;
     let end = bytes.iter().position(|&b| b == 0)?;
     Some(&bytes[..end])
@@ -427,7 +427,7 @@ fn ref_key<E: Target>(ctx: &Context<E>, i: usize) -> Option<RefKey> {
             targets.sort_by_key(|t| t.0);
             // The relocated fields hold per-object addends (x86-64
             // embeds the target's address); the targets stand for them.
-            let mut bytes = isec.data().to_vec();
+            let mut bytes = isec.contents().to_vec();
             for rel in rels {
                 let (a, b) = (rel.offset as usize, rel.offset as usize + rel.size as usize);
                 bytes[a..b].fill(0);
@@ -581,7 +581,7 @@ pub fn fold_objc_classrefs<E: Target>(ctx: &mut Context<E>) {
         // A pair's halves go together, as its offset half decides.
         let mut keep = hashbrown::HashSet::new();
         for u in &uses[obj_idx] {
-            let data = ctx.isecs[u.isec as usize].data();
+            let data = ctx.isecs[u.isec as usize].contents();
             let relocs = &ctx.objs[obj_idx].relocs;
             let decider = offset_half[obj_idx].get(&u.k).copied().unwrap_or(u.k);
             let (rel, decider) = (relocs[u.k], relocs[decider]);
@@ -621,7 +621,7 @@ pub fn fold_objc_classrefs<E: Target>(ctx: &mut Context<E>) {
                 ctx.symbols[class].add_flags(NEEDS_GOT);
                 kept.push((slot, class));
             } else {
-                ctx.isecs[slot as usize].set_alive(false);
+                ctx.isecs[slot as usize].kill();
             }
         }
     }
@@ -1030,7 +1030,7 @@ fn classic_list_header(data: &[u8]) -> Option<(u32, u64)> {
 fn classic_methods<E: Target>(ctx: &Context<E>, list: u32) -> Option<Vec<(u32, ObjcRef, ObjcRef)>> {
     // Not in the relative form already (the top flag), and 24 bytes an
     // entry.
-    let (entsize_flags, count) = classic_list_header(ctx.isecs[list as usize].data())?;
+    let (entsize_flags, count) = classic_list_header(ctx.isecs[list as usize].contents())?;
     if entsize_flags & 0x8000_0000 != 0 || entsize_flags & 0xffff != 24 {
         return None;
     }
@@ -1112,7 +1112,7 @@ pub fn merge_objc_categories<E: Target>(ctx: &mut Context<E>) {
         retarget_class_data(ctx, class.meta, meta_ro);
 
         for &ci in &class.cats {
-            ctx.isecs[cats[ci].isec as usize].set_alive(false);
+            ctx.isecs[cats[ci].isec as usize].kill();
             cats[ci].merged = true;
         }
         if !class.nonlazy && class.cats.iter().any(|&ci| cats[ci].nonlazy) {
@@ -1398,7 +1398,7 @@ fn read_method_list<E: Target>(
     if relative {
         return None;
     }
-    let (entsize_flags, count) = classic_list_header(ctx.isecs[isec as usize].data())?;
+    let (entsize_flags, count) = classic_list_header(ctx.isecs[isec as usize].contents())?;
     if entsize_flags != 24 {
         return None;
     }
@@ -1419,7 +1419,7 @@ fn read_method_list<E: Target>(
 fn read_protocol_list<E: Target>(ctx: &Context<E>, list: Option<ObjcRef>) -> Option<Vec<ObjcRef>> {
     let Some(r) = list else { return Some(Vec::new()) };
     let (isec, off) = objc_ref_location(ctx, r)?;
-    let data = ctx.isecs[isec as usize].data();
+    let data = ctx.isecs[isec as usize].contents();
     let count = u64::from_le_bytes(data.get(off as usize..off as usize + 8)?.try_into().unwrap());
     (0..count).map(|i| objc_pointer_at(ctx, isec, off + 8 + 8 * i)).collect()
 }
@@ -1432,7 +1432,7 @@ fn read_property_list<E: Target>(
 ) -> Option<Vec<(ObjcRef, ObjcRef)>> {
     let Some(r) = list else { return Some(Vec::new()) };
     let (isec, off) = objc_ref_location(ctx, r)?;
-    let data = ctx.isecs[isec as usize].data();
+    let data = ctx.isecs[isec as usize].contents();
     let entsize = u32::from_le_bytes(data.get(off as usize..off as usize + 4)?.try_into().unwrap());
     let count =
         u32::from_le_bytes(data.get(off as usize + 4..off as usize + 8)?.try_into().unwrap())
@@ -1615,7 +1615,7 @@ fn drop_superseded_lists<E: Target>(
 
 fn drop_list<E: Target>(ctx: &mut Context<E>, list: Option<ObjcRef>) {
     if let Some((isec, 0)) = list.and_then(|r| objc_ref_location(ctx, r)) {
-        ctx.isecs[isec as usize].set_alive(false);
+        ctx.isecs[isec as usize].kill();
     }
 }
 
@@ -1635,7 +1635,7 @@ fn rewrite_ro<E: Target>(
     protocols: Option<ObjcRef>,
     props: Option<ObjcRef>,
 ) -> u32 {
-    let data = ctx.isecs[ro.0 as usize].data()[ro.1 as usize..ro.1 as usize + 16].to_vec();
+    let data = ctx.isecs[ro.0 as usize].contents()[ro.1 as usize..ro.1 as usize + 16].to_vec();
     let flags = u32::from_le_bytes(data[0..4].try_into().unwrap());
     let len = if flags & (1 << 6) != 0 { 80 } else { 72 };
     let mut fields = vec![DataField::Bytes(data)];
@@ -1664,7 +1664,7 @@ fn rewrite_ro<E: Target>(
         // The record was a subsection of its own: replace it, so its
         // symbol names the new record too (ld64 keeps
         // __OBJC_CLASS_RO_$_Foo).
-        isec.set_alive(false);
+        isec.kill();
         isec.replacement = blob;
     }
     blob
@@ -1701,7 +1701,7 @@ fn rebuild_category_lists<E: Target>(
         if !list.entries.iter().any(|&(_, ci)| merged(ci)) {
             continue;
         }
-        ctx.isecs[list.isec as usize].set_alive(false);
+        ctx.isecs[list.isec as usize].kill();
         let survivors: Vec<DataField> = (list.entries.iter())
             .filter(|&&(_, ci)| !merged(ci))
             .map(|&(r, _)| DataField::Ptr(r))

macho/output_sections.rs

@@ -803,7 +803,7 @@ fn group_input_sections<E: Target>(
                 };
                 let Some(group) = group else {
                     // Consumed by the link: no output section.
-                    isec.set_alive(false);
+                    isec.kill();
                     continue;
                 };
                 let group = &mut groups[group].1;

macho/passes.rs

@@ -972,7 +972,7 @@ fn retire_bitcode_placeholders<E: Target>(ctx: &mut Context<E>) {
 pub fn remove_unreachable_files<E: Target>(ctx: &mut Context<E>) {
     for isec in ctx.isecs.iter_mut() {
         if !ctx.objs[isec.file as usize].is_alive {
-            isec.set_alive(false);
+            isec.kill();
         }
     }
 
@@ -996,7 +996,7 @@ pub fn remove_swift_reflection_metadata<E: Target>(ctx: &mut Context<E>) {
         })
         .collect();
     for i in removed {
-        ctx.isecs[i].set_alive(false);
+        ctx.isecs[i].kill();
     }
 }
 
@@ -1074,7 +1074,7 @@ pub fn convert_init_offsets<E: Target>(ctx: &mut Context<E>) {
             };
             ctx.init_offsets.init_funcs.push(func);
         }
-        ctx.isecs[i].set_alive(false);
+        ctx.isecs[i].kill();
     }
 }
 
@@ -1287,7 +1287,7 @@ pub fn merge_literals<E: Target>(ctx: &mut Context<E>) {
             if !input_files::is_mergeable_literal(hdr, isec) {
                 return None;
             }
-            Some((xxhash_rust::xxh3::xxh3_64(isec.data()), hdr, i as u32))
+            Some((xxhash_rust::xxh3::xxh3_64(isec.contents()), hdr, i as u32))
         })
         .collect();
 
@@ -1324,13 +1324,13 @@ fn merge_shard(isecs: &[InputSection], shard: Vec<Literal>) -> Vec<(u32, u32)> {
     let mut losers: Vec<(u32, u32)> = Vec::new();
     let p2align = |i: u32| isecs[i as usize].p2align_at(isecs[i as usize].input_addr as u64);
     for (hash, hdr, i) in shard {
-        let data = isecs[i as usize].data();
+        let data = isecs[i as usize].contents();
         let same = |&(h, other, j, _): &(u64, &MachSection, u32, u32)| {
             h == hash
                 && other.segname == hdr.segname
                 && other.sectname == hdr.sectname
                 && other.section_type() == hdr.section_type()
-                && isecs[j as usize].data() == data
+                && isecs[j as usize].contents() == data
         };
         match table.entry(hash, same, |e| e.0) {
             hashbrown::hash_table::Entry::Occupied(e) => {

macho/relocatable.rs

@@ -975,19 +975,21 @@ fn copy_section_contents<E: Target>(
         let osec = ctx.output_section(osec);
         if !osec.hdr.is_zerofill() {
             let isecs = osec.members.iter().map(|&id| &ctx.isecs[id]);
-            jobs.extend(isecs.filter(|isec| !isec.data().is_empty()).map(|isec| (&osec.hdr, isec)));
+            jobs.extend(
+                isecs.filter(|isec| !isec.contents().is_empty()).map(|isec| (&osec.hdr, isec)),
+            );
         }
     }
     let ranges: Vec<std::ops::Range<u64>> = jobs
         .iter()
         .map(|&(hdr, isec)| {
             let start = hdr.fileoff + isec.offset as u64;
-            start..start + isec.data().len() as u64
+            start..start + isec.contents().len() as u64
         })
         .collect();
     let slices = output_file::split_ranges(buf, &ranges);
     jobs.into_par_iter().zip(slices).for_each(|((hdr, isec), out)| {
-        out.copy_from_slice(isec.data());
+        out.copy_from_slice(isec.contents());
         for rel in isec.rels(&ctx.objs[isec.file as usize]) {
             let here = hdr.addr + isec.offset as u64 + rel.offset as u64;
             rewrite_field(targets, isec, rel, here, &mut out[rel.offset as usize..]);