macho: fix linking of dylibs and frameworks

Previously, I have incorrectly assumed that with two-level namespace
we only need to link in dylibs/frameworks that actually export symbols
which are undefined in the linked image. Turns out, regardless of
whether we link with two-level namespace (default on macOS) or a
flat namespace (more common on other platforms), we always need to
put the dylibs/frameworks as specified by the user from the linker
line into the final linked image.

2 files changed, 12 insertions, 0 deletions

diff --git a/src/link/MachO.zig b/src/link/MachO.zig
index 36d5bc6a87..5d9b0e6fe1 100644
--- a/src/link/MachO.zig
+++ b/src/link/MachO.zig
@@ -1013,7 +1013,12 @@ fn parseInputFiles(self: *MachO, files: []const []const u8, syslibroot: ?[]const
             .syslibroot = syslibroot,
         })) |dylibs| {
             defer self.base.allocator.free(dylibs);
+            const dylib_id = @intCast(u16, self.dylibs.items.len);
             try self.dylibs.appendSlice(self.base.allocator, dylibs);
+            // We always have to add the dylib that was on the linker line.
+            if (!self.referenced_dylibs.contains(dylib_id)) {
+                try self.referenced_dylibs.putNoClobber(self.base.allocator, dylib_id, {});
+            }
             continue;
         }
 
@@ -1028,7 +1033,12 @@ fn parseLibs(self: *MachO, libs: []const []const u8, syslibroot: ?[]const u8) !v
             .syslibroot = syslibroot,
         })) |dylibs| {
             defer self.base.allocator.free(dylibs);
+            const dylib_id = @intCast(u16, self.dylibs.items.len);
             try self.dylibs.appendSlice(self.base.allocator, dylibs);
+            // We always have to add the dylib that was on the linker line.
+            if (!self.referenced_dylibs.contains(dylib_id)) {
+                try self.referenced_dylibs.putNoClobber(self.base.allocator, dylib_id, {});
+            }
             continue;
         }
 
diff --git a/src/link/MachO/Dylib.zig b/src/link/MachO/Dylib.zig
index 4763203c3b..71301ccbbf 100644
--- a/src/link/MachO/Dylib.zig
+++ b/src/link/MachO/Dylib.zig
@@ -193,6 +193,8 @@ pub fn createAndParseFromPath(
     defer dylibs.deinit();
 
     try dylibs.append(dylib);
+    // TODO this should not be performed if the user specifies `-flat_namespace` flag.
+    // See ld64 manpages.
     try dylib.parseDependentLibs(allocator, arch, &dylibs, opts.syslibroot);
 
     return dylibs.toOwnedSlice();