[PATCH] D68818: [hip][cuda] Fix the extended lambda name mangling issue.

[Michael Liao via Phabricator via cfe-commits]

hliao created this revision.
hliao added reviewers: tra, rsmith, yaxunl.
Herald added a reviewer: martong.
Herald added a reviewer: shafik.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

- HIP/CUDA host side needs to use device kernel symbol name to match the device side binaries. Without a consistent naming between host- and device-side compilations, it's risky that wrong device binaries are executed. Consistent naming is usually not an issue until unnamed types are used, especially the lambda. In this patch, the consistent name mangling is addressed for the extended lambdas, i.e. the lambdas annotated with `__device__`.
- In [Itanium C++ ABI][1], the mangling of the lambda is generally unspecified unless, in certain cases, ODR rule is required to ensure consisent naming cross TUs. The extended lambda is such a case as its name may be part of a device kernel function, e.g., the extended lambda is used as a template argument and etc. Thus, we need to force ODR for extended lambdas as they are referenced in both device- and host-side TUs. Furthermore, if a extended lambda is nested in other (extended or not) lambdas, those lambdas are required to follow ODR naming as well. This patch revises the current lambda mangle numbering to force ODR from an extended lambda to all its parent lambdas.
- On the other side, the aforementioned ODR naming should not change those lambdas' original linkages, i.e., we cannot replace the original `internal` with `linkonce_odr`; otherwise, we may violate ODR in general. This patch introduces a new field `HasKnownInternalLinkage` in lambda data to decouple the current linkage calculation based on mangling number assigned.

[1]: https://itanium-cxx-abi.github.io/cxx-abi/abi.html


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D68818

Files:
  clang/include/clang/AST/DeclCXX.h
  clang/include/clang/Sema/Sema.h
  clang/lib/AST/ASTImporter.cpp
  clang/lib/AST/Decl.cpp
  clang/lib/AST/DeclCXX.cpp
  clang/lib/Sema/SemaLambda.cpp
  clang/lib/Sema/TreeTransform.h
  clang/lib/Serialization/ASTReaderDecl.cpp
  clang/lib/Serialization/ASTWriter.cpp
  clang/test/CodeGenCUDA/unnamed-types.cu

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