Commit 7e530c13b3
Changed files (1)
src
link
MachO
src/link/MachO/Object.zig
@@ -308,7 +308,7 @@ fn initSubsections(self: *Object, allocator: Allocator, nlists: anytype) !void {
} else nlists.len;
if (nlist_start == nlist_end or nlists[nlist_start].nlist.n_value > sect.addr) {
- const name = try std.fmt.allocPrintZ(allocator, "{s}${s}", .{ sect.segName(), sect.sectName() });
+ const name = try std.fmt.allocPrintZ(allocator, "{s}${s}$begin", .{ sect.segName(), sect.sectName() });
defer allocator.free(name);
const size = if (nlist_start == nlist_end) sect.size else nlists[nlist_start].nlist.n_value - sect.addr;
const atom_index = try self.addAtom(allocator, .{
@@ -359,6 +359,25 @@ fn initSubsections(self: *Object, allocator: Allocator, nlists: anytype) !void {
self.symtab.items(.size)[nlists[i].idx] = size;
}
}
+
+ // Some compilers such as Go reference the end of a section (addr + size)
+ // which cannot be contained in any non-zero atom (since then this atom
+ // would exceed section boundaries). In order to facilitate this behaviour,
+ // we create a dummy zero-sized atom at section end (addr + size).
+ const name = try std.fmt.allocPrintZ(allocator, "{s}${s}$end", .{ sect.segName(), sect.sectName() });
+ defer allocator.free(name);
+ const atom_index = try self.addAtom(allocator, .{
+ .name = try self.addString(allocator, name),
+ .n_sect = @intCast(n_sect),
+ .off = sect.size,
+ .size = 0,
+ .alignment = sect.@"align",
+ });
+ try self.atoms_indexes.append(allocator, atom_index);
+ try subsections.append(allocator, .{
+ .atom = atom_index,
+ .off = sect.size,
+ });
}
}
@@ -743,7 +762,7 @@ pub fn findAtom(self: Object, addr: u64) ?Atom.Index {
const slice = self.sections.slice();
for (slice.items(.header), slice.items(.subsections), 0..) |sect, subs, n_sect| {
if (subs.items.len == 0) continue;
- if (sect.addr == addr) return subs.items[0].atom;
+ if (addr == sect.addr) return subs.items[0].atom;
if (sect.addr < addr and addr < sect.addr + sect.size) {
return self.findAtomInSection(addr, @intCast(n_sect));
}
@@ -794,7 +813,19 @@ fn linkNlistToAtom(self: *Object, macho_file: *MachO) !void {
defer tracy.end();
for (self.symtab.items(.nlist), self.symtab.items(.atom)) |nlist, *atom| {
if (!nlist.stab() and nlist.sect()) {
- if (self.findAtomInSection(nlist.n_value, nlist.n_sect - 1)) |atom_index| {
+ const sect = self.sections.items(.header)[nlist.n_sect - 1];
+ const subs = self.sections.items(.subsections)[nlist.n_sect - 1].items;
+ if (nlist.n_value == sect.addr) {
+ // If the nlist address is the start of the section, return the first atom
+ // since it is guaranteed to always start at section's start address.
+ atom.* = subs[0].atom;
+ } else if (nlist.n_value == sect.addr + sect.size) {
+ // If the nlist address matches section's boundary (address + size),
+ // return the last atom since it is guaranteed to always point
+ // at the section's end boundary.
+ atom.* = subs[subs.len - 1].atom;
+ } else if (self.findAtomInSection(nlist.n_value, nlist.n_sect - 1)) |atom_index| {
+ // In all other cases, do a binary search to find a matching atom for the symbol.
atom.* = atom_index;
} else {
try macho_file.reportParseError2(self.index, "symbol {s} not attached to any (sub)section", .{