[libc++] Reject abilist if it contains an ABI tag

[philnik777]

We currently don't have any ABI tags in our dylib symbols, and this is unlikely to change in the future. By diagnosing this we avoid accidentally adding one through e.g. having _LIBCPP_HIDE_FROM_ABI on an exported symbol.

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Nikolas Klauser (philnik777)

Changes

We currently don't have any ABI tags in our dylib symbols, and this is unlikely to change in the future. By diagnosing this we avoid accidentally adding one through e.g. having _LIBCPP_HIDE_FROM_ABI on an exported symbol.

---

Full diff: https://github.com/llvm/llvm-project/pull/139030.diff

1 Files Affected:

• (modified) libcxx/utils/sym_diff.py (+5)

diff --git a/libcxx/utils/sym_diff.py b/libcxx/utils/sym_diff.py
index 8eaf8b7a57591..91af4a0bddaa7 100755
--- a/libcxx/utils/sym_diff.py
+++ b/libcxx/utils/sym_diff.py
@@ -80,6 +80,11 @@ def main():
         old_syms_list, _ = util.filter_stdlib_symbols(old_syms_list)
         new_syms_list, _ = util.filter_stdlib_symbols(new_syms_list)
 
+    for symbol in new_syms_list:
+        if 'B' in symbol["name"]:
+            print(f"Symbol {symbol["name"]} contains an ABI tag!")
+            sys.exit(1)
+
     added, removed, changed = diff.diff(old_syms_list, new_syms_list)
     if args.removed_only:
         added = {}

[ldionne]

Would it be possible to add this as a lit test instead? One thing we could potentially do is nm -g %{lib-dir}/libc++.dylib | grep -v 'B' or something along those lines?

[philnik777]

Since the name of the library changes depending on the platform this is non-trivial I think. Do you have any idea how to get that except passing it through as another lit substitution?