Commit Graph

3 Commits

Author SHA1 Message Date
Nathan Sidwell ae4dce8659 [clang][ABI] New C++20 module mangling scheme
Implement a demangleable strong ownership symbol mangling.

 * The original module symbol mangling scheme turned out to be
undemangleable.

 * The hoped-for C++17 compatibility of weak ownership turns out to be
fragile

* C++20 now has better ways of controlling C++17 compatibility

The issue is captured on the ABI list at:
  https://github.com/itanium-cxx-abi/cxx-abi/issues/134

GCC implements this new mangling.

The old mangling is unceremoniously dropped.  No backwards
compatibility, no deprectated old-mangling flag.  It was always
labelled experimental.  (Old and new manglings cannot be confused.)

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D122256
2022-03-30 08:51:27 -07:00
Chuanqi Xu 845f0bb5fa Revert "[clang][ABI] New C++20 module mangling scheme"
This reverts commit 21e16ab6b8.

It looks like it would break builds in mac. See
https://reviews.llvm.org/D118352.
2022-03-09 10:15:15 +08:00
Nathan Sidwell 21e16ab6b8 [clang][ABI] New C++20 module mangling scheme
The existing module symbol mangling scheme turns out to be
undemangleable.  It is also desirable to switch to the
strong-ownership model as the hoped-for C++17 compatibility turns out
to be fragile, and we also now have a better way of controlling that.

The issue is captured on the ABI list at:
  https://github.com/itanium-cxx-abi/cxx-abi/issues/134

A document describing the issues and new mangling is at:
  https://drive.google.com/file/d/1qQjqptzOFT_lfXH8L6-iD9nCRi34wjft/view

This patch is the code-generation part.  I have a demangler too, but
that patch is based on some to-be-landed refactoring of the demangler.

The old mangling is unceremoniously dropped.  No backwards
compatibility, no deprectated old-mangling flag.  It was always
labelled experimental.  (Old and new manglings cannot be confused.)

Reviewed By: ChuanqiXu

Differential Revision: https://reviews.llvm.org/D118352
2022-03-08 06:21:50 -08:00