[lld-macho][nfc] Added some notes on deliberate differences btw LD64 vs LLD-MACHO
For future references and to help with debugging crashes, this could be useful.
Differential Revision: https://reviews.llvm.org/D110464
GitOrigin-RevId: 6b715e9c4d9cc00f59906d48cd57f4c767229093
diff --git a/MachO/ld64-vs-lld.rst b/MachO/ld64-vs-lld.rst
new file mode 100644
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+==================
+LD64 vs LLD-MACHO
+==================
+
+This doc lists all significant deliberate differences in behavior between LD64 and LLD-MachO.
+
+ObjC symbols treatment
+**********************
+There are differences in how LLD and LD64 handle ObjC symbols loaded from archives.
+
+- LD64:
+ * Duplicate ObjC symbols from the same archives will not raise an error. LD64 will pick the first one.
+ * Duplicate ObjC symbols from different archives will raise a "duplicate symbol" error.
+- LLD:
+ * Duplicate symbols, regardless of which archives they are from, will raise errors.
+
