[PATCH] D79344: [cuda] Start diagnosing variables with bad target.

[Michael Liao via Phabricator via cfe-commits]

hliao created this revision.
hliao added reviewers: tra, rjmccall, yaxunl.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
hliao added a comment.

That test code just passed compilation on clang trunk if only assembly code is generated, https://godbolt.org/z/XYjRcT. But NVCC generates errors on all cases.


- Non-local variables on the host side are generally not accessible from the device side. Without proper diagnostic messages, the compilation may pass until the final linking stage. That link error may not be intuitive enough for developers, especially for relocatable code compilation. For certain cases like assembly output only, it is even worse that the compilation just passes.
- This patch addresses that issue by checking the use of non-local variables and issuing errors on bad target references. For references through default argumennts, a warning is generated on the function declaration as, at that point, that variables are just bound. No real code would be generated if that function won't be used.
- The oppose direction, i.e. accessing device variables from the host side, is NOT addressed in this patch as the host code allows the access those device variables by using runtime interface on their shadow variables. It needs more support to identify how that variable is used on the host side for simple cases. The comprehensive diagnosing would be so expensive that alternative analysis tools like clang-tidy should be used.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D79344

Files:
  clang/include/clang/Basic/DiagnosticGroups.td
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/include/clang/Sema/Sema.h
  clang/include/clang/Sema/SemaInternal.h
  clang/lib/Sema/SemaCUDA.cpp
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/lib/Sema/SemaExpr.cpp
  clang/lib/Sema/SemaLambda.cpp
  clang/test/CodeGenCUDA/function-overload.cu
  clang/test/SemaCUDA/variable-target.cu

-------------- next part --------------
A non-text attachment was scrubbed...
Name: D79344.261882.patch
Type: text/x-patch
Size: 25607 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20200504/a6055d39/attachment-0001.bin>