[libcxx] Workaround for build error after #108999

[vitalybuka]

We see erros like following after #108999

FAILED: include/c++/v1/libcxx.imp ./libcxx_build_msan/include/c++/v1/libcxx.imp
cd ./libcxx_build_msan/libcxx/include && /usr/bin/python3 ./llvm-project/libcxx/utils/generate_iwyu_mapping.py -o ./libcxx_build_msan/include/c++/v1/libcxx.imp
Traceback (most recent call last):
  File "./llvm-project/libcxx/utils/generate_iwyu_mapping.py", line 94, in <module>
    main(sys.argv[1:])
  File "./llvm-project/libcxx/utils/generate_iwyu_mapping.py", line 84, in main
    raise RuntimeError(f"{header}: Header {public} is not a valid header")
RuntimeError: __cxx03/__algorithm/all_of.h: Header cxx03 is not a valid header
ninja: build stopped: subcommand failed.

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Vitaly Buka (vitalybuka)

Changes

FAILED: include/c++/v1/libcxx.imp ./libcxx_build_msan/include/c++/v1/libcxx.imp
cd ./libcxx_build_msan/libcxx/include && /usr/bin/python3 ./llvm-project/libcxx/utils/generate_iwyu_mapping.py -o ./libcxx_build_msan/include/c++/v1/libcxx.imp
Traceback (most recent call last):
  File "./llvm-project/libcxx/utils/generate_iwyu_mapping.py", line 94, in <module>
    main(sys.argv[1:])
  File "./llvm-project/libcxx/utils/generate_iwyu_mapping.py", line 84, in main
    raise RuntimeError(f"{header}: Header {public} is not a valid header")
RuntimeError: __cxx03/__algorithm/all_of.h: Header cxx03 is not a valid header
ninja: build stopped: subcommand failed.

---

Full diff: https://github.com/llvm/llvm-project/pull/110783.diff

1 Files Affected:

• (modified) libcxx/utils/generate_iwyu_mapping.py (+1)

diff --git a/libcxx/utils/generate_iwyu_mapping.py b/libcxx/utils/generate_iwyu_mapping.py
index 599201808bb79b..dadf6b58bd98a8 100644
--- a/libcxx/utils/generate_iwyu_mapping.py
+++ b/libcxx/utils/generate_iwyu_mapping.py
@@ -15,6 +15,7 @@ def IWYU_mapping(header: str) -> typing.Optional[typing.List[str]]:
         "__pstl/.+",
         "__support/.+",
         "__utility/private_constructor_tag.h",
+        "__cxx03/.+", # FIXME: Workaround for https://github.com/llvm/llvm-project/pull/108999
     ]
     if any(re.match(pattern, header) for pattern in ignore):
         return None

[github-actions]

✅ With the latest revision this PR passed the Python code formatter.

[ldionne]

The patch has since then been reverted, but I guess this is something that @philnik777 should have a look into before it is re-landed.

[vitalybuka]

Thanks!