[libcxx-commits] [libcxx] [libcxx] Support ABI symbol sizes on macOS (PR #75623)

[Will Hawkins via libcxx-commits]

================
@@ -123,6 +123,40 @@ def adjust_mangled_name(name):
     return name[1:]
 
 
+def extract_object_sizes_from_map(mapfilename: str):
+    maplines = []
+    result = {}
+
+    with open(mapfilename, "r") as f:
+        maplines = f.readlines()
+
+    if len(maplines) == 0:
+        return {}
+
+    # Yes, this is fragile.
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hawkinsw wrote:

Unfortunately, yes, it only works with the Darwin linker (`/usr/bin/ld`). I attempted to duplicate it with the linker on Linux but, although The GNU Linker does support map files, it does not give us enough information. So, I think that we are stuck with having a solution limited to the Darwin linker.

https://github.com/llvm/llvm-project/pull/75623