https://github.com/yxsamliu created https://github.com/llvm/llvm-project/pull/83870
In -fgpu-rdc mode, when an external kernel is used by a host function with weak_odr linkage (e.g. explicitly instantiated template function), the kernel should not be marked as host-used external kernel, since the host function may be dropped by the linker. Mark the external kernel as host-used external kernel will force a reference to the external kernel, which the user may not define in other TU. Fixes: https://github.com/llvm/llvm-project/issues/83771 >From 3097ccf002464823262f73e53087ea9129f8e7ee Mon Sep 17 00:00:00 2001 From: "Yaxun (Sam) Liu" <yaxun....@amd.com> Date: Mon, 4 Mar 2024 11:38:06 -0500 Subject: [PATCH] [HIP] fix host-used external kernel In -fgpu-rdc mode, when an external kernel is used by a host function with weak_odr linkage (e.g. explicitly instantiated template function), the kernel should not be marked as host-used external kernel, since the host function may be dropped by the linker. Mark the external kernel as host-used external kernel will force a reference to the external kernel, which the user may not define in other TU. Fixes: https://github.com/llvm/llvm-project/issues/83771 --- clang/lib/Sema/SemaCUDA.cpp | 3 ++- clang/lib/Sema/SemaExpr.cpp | 4 +++- clang/test/CodeGenCUDA/host-used-extern.cu | 13 +++++++++++++ 3 files changed, 18 insertions(+), 2 deletions(-) diff --git a/clang/lib/Sema/SemaCUDA.cpp b/clang/lib/Sema/SemaCUDA.cpp index 6a66ecf6f94c17..40a2d47e4da127 100644 --- a/clang/lib/Sema/SemaCUDA.cpp +++ b/clang/lib/Sema/SemaCUDA.cpp @@ -895,7 +895,8 @@ bool Sema::CheckCUDACall(SourceLocation Loc, FunctionDecl *Callee) { if (DiagKind == SemaDiagnosticBuilder::K_Nop) { // For -fgpu-rdc, keep track of external kernels used by host functions. if (LangOpts.CUDAIsDevice && LangOpts.GPURelocatableDeviceCode && - Callee->hasAttr<CUDAGlobalAttr>() && !Callee->isDefined()) + Callee->hasAttr<CUDAGlobalAttr>() && !Callee->isDefined() && + getASTContext().GetGVALinkageForFunction(Caller) == GVA_StrongExternal) getASTContext().CUDAExternalDeviceDeclODRUsedByHost.insert(Callee); return true; } diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp index 0a449fc1082bd4..dd16fc4eeffb72 100644 --- a/clang/lib/Sema/SemaExpr.cpp +++ b/clang/lib/Sema/SemaExpr.cpp @@ -19211,7 +19211,9 @@ MarkVarDeclODRUsed(ValueDecl *V, SourceLocation Loc, Sema &SemaRef, } else if (VarTarget == Sema::CVT_Device && !Var->hasAttr<CUDASharedAttr>() && (UserTarget == Sema::CFT_Host || - UserTarget == Sema::CFT_HostDevice)) { + UserTarget == Sema::CFT_HostDevice) && + SemaRef.getASTContext().GetGVALinkageForFunction(FD) == + GVA_StrongExternal) { // Record a CUDA/HIP device side variable if it is ODR-used // by host code. This is done conservatively, when the variable is // referenced in any of the following contexts: diff --git a/clang/test/CodeGenCUDA/host-used-extern.cu b/clang/test/CodeGenCUDA/host-used-extern.cu index e8f8e12aad47d1..1db6123916c700 100644 --- a/clang/test/CodeGenCUDA/host-used-extern.cu +++ b/clang/test/CodeGenCUDA/host-used-extern.cu @@ -24,6 +24,7 @@ // NEG-NOT: @__clang_gpu_used_external = {{.*}} @_Z7kernel2v // NEG-NOT: @__clang_gpu_used_external = {{.*}} @_Z7kernel3v +// XEG-NOT: @__clang_gpu_used_external = {{.*}} @_Z7kernel5v // NEG-NOT: @__clang_gpu_used_external = {{.*}} @var2 // NEG-NOT: @__clang_gpu_used_external = {{.*}} @var3 // NEG-NOT: @__clang_gpu_used_external = {{.*}} @ext_shvar @@ -44,6 +45,10 @@ __global__ void kernel3(); // kernel4 is marked as used even though it is not called. __global__ void kernel4(); +// kernel5 is not marked as used since it is called by host function +// with linkonce_odr linkage, which may be dropped by linker. +__global__ void kernel5(); + extern __device__ int var1; __device__ int var2; @@ -67,3 +72,11 @@ __global__ void test_lambda_using_extern_shared() { }; lambda(); } + +template<class T> +void template_caller() { + kernel5<<<1, 1>>>(); + var1 = 1; +} + +template void template_caller<int>(); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
