[PATCH] D47201: [CUDA] Implement nv_weak attribute for functions

[Jonas Hahnfeld via Phabricator via cfe-commits]

Hahnfeld created this revision.
Hahnfeld added a reviewer: tra.
Herald added a subscriber: cfe-commits.

This is needed for relocatable device code with CUDA 9 and later.
Before this patch, linking two or more object files resulted in
"Multiple definition" errors for a group of functions from
cuda_device_runtime_api.h which are annoted with "nv_weak".

CUDA headers already used this attribute in earlier releases, but
until CUDA 8.0 the only definitions in cuda_device_runtime_api.h
were conditional under `defined(__CUDABE__)` which is explicitly
undefined in Clang's wrapper. However since CUDA 9.0 this has
changed to `!defined(__CUDACC_RTC__)`. Trying to add that define
resulted in errors that nvrtc_device_runtime.h could not be found.

Reported by Andrea Bocci!


Repository:
  rC Clang

https://reviews.llvm.org/D47201

Files:
  include/clang/Basic/Attr.td
  include/clang/Basic/DiagnosticSemaKinds.td
  lib/CodeGen/CodeGenModule.cpp
  lib/Sema/SemaDecl.cpp
  lib/Sema/SemaDeclAttr.cpp
  test/CodeGenCUDA/nv_weak.cu
  test/SemaCUDA/attr-declspec.cu
  test/SemaCUDA/attr-nv_weak.cu
  test/SemaCUDA/attributes-on-non-cuda.cu

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