macho: skip debug sections when matching nlists to subsections

kubkon · Dec 16, 2023 · e9856b3 · e9856b3
1 parent 228be14
commit e9856b3
Showing 1 changed file with 17 additions and 15 deletions.
diff --git a/src/MachO/Object.zig b/src/MachO/Object.zig
@@ -144,14 +144,17 @@ inline fn isLiteral(sect: macho.section_64) bool {
     };
 }
 
+inline fn isDebug(sect: macho.section_64) bool {
+    return sect.attrs() & macho.S_ATTR_DEBUG != 0 or
+        mem.eql(u8, sect.sectName(), "__eh_frame") or
+        mem.eql(u8, sect.sectName(), "__compact_unwind");
+}
+
 fn initSubsections(self: *Object, nlists: anytype, macho_file: *MachO) !void {
     const gpa = macho_file.base.allocator;
     const slice = self.sections.slice();
     for (slice.items(.header), slice.items(.subsections), 0..) |sect, *subsections, n_sect| {
-        if (sect.attrs() & macho.S_ATTR_DEBUG != 0) continue;
-        if (self.eh_frame_sect_index) |index| if (index == n_sect) continue;
-        if (self.compact_unwind_sect_index) |index| if (index == n_sect) continue;
-        if (isLiteral(sect)) continue;
+        if (isDebug(sect) or isLiteral(sect)) continue;
 
         const nlist_start = for (nlists, 0..) |nlist, i| {
             if (nlist.nlist.n_sect - 1 == n_sect) break i;
@@ -220,10 +223,7 @@ fn initSections(self: *Object, nlists: anytype, macho_file: *MachO) !void {
     try self.atoms.ensureUnusedCapacity(gpa, self.sections.items(.header).len);
 
     for (slice.items(.header), 0..) |sect, n_sect| {
-        if (sect.attrs() & macho.S_ATTR_DEBUG != 0) continue;
-        if (self.eh_frame_sect_index) |index| if (index == n_sect) continue;
-        if (self.compact_unwind_sect_index) |index| if (index == n_sect) continue;
-        if (isLiteral(sect)) continue;
+        if (isDebug(sect) or isLiteral(sect)) continue;
 
         const name = try std.fmt.allocPrintZ(gpa, "{s}${s}", .{ sect.segName(), sect.sectName() });
         defer gpa.free(name);
@@ -297,10 +297,7 @@ fn initLiteralSections(self: *Object, macho_file: *MachO) !void {
     try self.atoms.ensureUnusedCapacity(gpa, self.sections.items(.header).len);
 
     for (slice.items(.header), 0..) |sect, n_sect| {
-        if (sect.attrs() & macho.S_ATTR_DEBUG != 0) continue;
-        if (self.eh_frame_sect_index) |index| if (index == n_sect) continue;
-        if (self.compact_unwind_sect_index) |index| if (index == n_sect) continue;
-        if (!isLiteral(sect)) continue;
+        if (isDebug(sect) or !isLiteral(sect)) continue;
 
         const name = try std.fmt.allocPrintZ(gpa, "{s}${s}", .{ sect.segName(), sect.sectName() });
         defer gpa.free(name);
@@ -318,7 +315,9 @@ fn initLiteralSections(self: *Object, macho_file: *MachO) !void {
 
 pub fn findAtom(self: Object, addr: u64) ?Atom.Index {
     for (self.sections.items(.header), 0..) |sect, n_sect| {
-        if (sect.addr <= addr and addr < sect.addr + sect.size) {
+        if ((sect.addr <= addr and addr < sect.addr + sect.size) or
+            (sect.addr == addr and sect.size == 0))
+        {
             return self.findAtomInSection(addr, @intCast(n_sect));
         }
     }
@@ -337,15 +336,18 @@ fn findAtomInSection(self: Object, addr: u64, n_sect: u8) ?Atom.Index {
             subsections.items[idx + 1].off - sub.off
         else
             sect.size - sub.off;
-        if (sub_addr <= addr and addr < sub_addr + sub_size) return sub.atom;
+        if ((sub_addr <= addr and addr < sub_addr + sub_size) or
+            (sub_addr == addr and sub_size == 0))
+            return sub.atom;
     }
     return null;
 }
 
 fn linkNlistToAtom(self: *Object, macho_file: *MachO) !void {
     for (self.symtab.items(.nlist), self.symtab.items(.atom)) |nlist, *atom| {
         if (!nlist.stab() and nlist.sect()) {
-            // if (sect.attrs() & macho.S_ATTR_DEBUG != 0) continue;
+            const sect = self.sections.items(.header)[nlist.n_sect - 1];
+            if (isDebug(sect)) continue;
             if (self.findAtomInSection(nlist.n_value, nlist.n_sect - 1)) |atom_index| {
                 atom.* = atom_index;
             } else {