[PATCH] D85223: [CUDA][HIP] Support accessing static device variable in host code for -fgpu-rdc

[Yaxun Liu via Phabricator via cfe-commits]

yaxunl created this revision.
yaxunl added reviewers: tra, rjmccall, JonChesterfield, hliao.
Herald added a subscriber: dang.
yaxunl requested review of this revision.

This is separated from https://reviews.llvm.org/D80858

For -fgpu-rdc mode, static device vars in different TU's may have the same name.
To support accessing file-scope static device variables in host code, we need to give them
a distinct name and external linkage. This can be done by postfixing each static device variable with
a distinct CUID (Compilation Unit ID). Also we have to make sure the host compilation and device
compilation of the same compilation unit use identical CUID.

This patch added a distinct CUID for each input file, which is represented by InputAction.
clang initially creates an InputAction for each input file for the host compilation. In CUDA/HIP action
builder, each InputAction is given a CUID and cloned for each GPU arch, and the CUID is also cloned. In this way,
we guarantee the corresponding device and host compilation for the same file shared the
same CUID, therefore the postfixed device variable and shadow variable share the same name.
On the other hand, different compilation units have different CUID, therefore a static variable
with the same name but in a different compilation unit will have a different name.

Since the static device variables have different name across compilation units, now we let
them have external linkage so that they can be looked up by the runtime.

-fuse-cuid=random|hash|none is added to control the method to generate CUID. The default
is hash. -cuid=X is also added to specify CUID explicitly, which overrides -fuse-cuid.


https://reviews.llvm.org/D85223

Files:
  clang/include/clang/AST/ASTContext.h
  clang/include/clang/Basic/DiagnosticDriverKinds.td
  clang/include/clang/Basic/LangOptions.h
  clang/include/clang/Driver/Action.h
  clang/include/clang/Driver/Compilation.h
  clang/include/clang/Driver/Options.td
  clang/lib/AST/ASTContext.cpp
  clang/lib/CodeGen/CGCUDANV.cpp
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/CodeGen/CodeGenModule.h
  clang/lib/Driver/Action.cpp
  clang/lib/Driver/Driver.cpp
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/lib/Frontend/CompilerInvocation.cpp
  clang/test/CodeGenCUDA/static-device-var-rdc.cu
  clang/test/Driver/hip-cuid.hip
  clang/test/Frontend/hip-cuid.hip
  clang/test/SemaCUDA/static-device-var.cu

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