[PATCH] D121951: [AMDGPU][OpenCL] Add "amdgpu-no-hostcall-ptr" in Clang codegen pre-COV_5

[Sameer Sahasrabuddhe via Phabricator via llvm-commits]

sameerds added inline comments.


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Comment at: clang/lib/CodeGen/TargetInfo.cpp:9381
+      M.getTarget().getTargetOpts().CodeObjectVersion != 500) {
+    F->addFnAttr("amdgpu-no-hostcall-ptr");
+  }
----------------
The frontend does not need to worry about this attribute. See the comment in the MetadataStreamer. A worthwhile check would be to generate an error if we are able to detect that some hostcall service is being used in OpenCL on code-object-v4 or lower. None exists right now, but we should add the check if such services show up. But those checks are likely to be in a different place. For example, enabling asan on OpenCL for code-object-v4 should result in an error in the place where asan commandline options are parsed.


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Comment at: llvm/lib/Target/AMDGPU/AMDGPUHSAMetadataStreamer.cpp:406-408
     if (Func.getParent()->getNamedMetadata("llvm.printf.fmts"))
       emitKernelArg(DL, Int8PtrTy, Align(8), ValueKind::HiddenPrintfBuffer);
+    else if (!Func.hasFnAttribute("amdgpu-no-hostcall-ptr"))
----------------
I would structure this differently: If this is code-object-v4 or lower, then if  "llvm.printf.fmts" is present, then this kernel clearly contains OpenCL bits, and cannot use hostcall. So it's okay to just assume that the no-hostcall-ptr attribute is always present in this situation, which means the only metadata generated is for ValueKind::HiddenPrintfBuffer. Else if this is code-object-v5, then proceed to emit both metadata.




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  https://reviews.llvm.org/D121951/new/

https://reviews.llvm.org/D121951