https://github.com/jhuber6 updated https://github.com/llvm/llvm-project/pull/67557
>From b87a2fd522c874a222aa497e0db1f5de5d35ff51 Mon Sep 17 00:00:00 2001 From: Joseph Huber <jhub...@vols.utk.edu> Date: Wed, 27 Sep 2023 09:03:16 -0500 Subject: [PATCH] [OpenMP] Implicitly include the 'lcgpu' and 'lmgpu' libraries for OpenMP Summary: [The LLVM C library for GPUs](https://libc.llvm.org/gpu/) supports standard function calls on the GPU that users are familiar with. Currently, this requires that users include these manually. The support for this library is dependent upon whether or not associated LLVM build was built with the GPU C library support. This patch implicitly adds these for an OpenMP offloading compilation if we find that the toolchain contains the GPU declarations that allow us to use this. I do not know how to test this, given that it requires information from the resource directory in the install. That means it won't be present for any internal tests. It works when I test it and the idea is simple enough so it should be simple enough. --- clang/include/clang/Driver/Options.td | 3 +++ clang/lib/Driver/ToolChains/CommonArgs.cpp | 22 ++++++++++++++++++++++ clang/test/Driver/openmp-offload-gpu.c | 15 +++++++++++++++ 3 files changed, 40 insertions(+) diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index f573f5a06ceb501..f8143651cd3c151 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -5055,6 +5055,9 @@ def nogpulib : Flag<["-"], "nogpulib">, MarshallingInfoFlag<LangOpts<"NoGPULib"> Visibility<[ClangOption, CC1Option]>, HelpText<"Do not link device library for CUDA/HIP device compilation">; def : Flag<["-"], "nocudalib">, Alias<nogpulib>; +def gpulibc : Flag<["-"], "gpulibc">, Visibility<[ClangOption, CC1Option]>, + HelpText<"Link the LLVM C Library for GPUs">; +def nogpulibc : Flag<["-"], "nogpulibc">, Visibility<[ClangOption, CC1Option]>; def nodefaultlibs : Flag<["-"], "nodefaultlibs">; def nodriverkitlib : Flag<["-"], "nodriverkitlib">; def nofixprebinding : Flag<["-"], "nofixprebinding">; diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp index 9777672ac1f4491..4c240e519f92274 100644 --- a/clang/lib/Driver/ToolChains/CommonArgs.cpp +++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp @@ -869,6 +869,25 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args, /*IsLTO=*/true, PluginOptPrefix); } +/// Adds the '-lcgpu' and '-lmgpu' libraries to the compilation to include the +/// LLVM C library for GPUs. +static void addOpenMPDeviceLibC(const ToolChain &TC, const ArgList &Args, + ArgStringList &CmdArgs) { + if (Args.hasArg(options::OPT_nogpulib) || Args.hasArg(options::OPT_nolibc)) + return; + + // Check the resource directory for the LLVM libc GPU declarations. If it's + // found we can assume that LLVM was built with support for the GPU libc. + SmallString<256> LibCDecls(TC.getDriver().ResourceDir); + llvm::sys::path::append(LibCDecls, "include", "llvm_libc_wrappers", + "llvm-libc-decls"); + bool HasLibC = llvm::sys::fs::exists(LibCDecls) && llvm::sys::fs::is_directory(LibCDecls); + if (Args.hasFlag(options::OPT_gpulibc, options::OPT_nogpulibc, HasLibC)) { + CmdArgs.push_back("-lcgpu"); + CmdArgs.push_back("-lmgpu"); + } +} + void tools::addOpenMPRuntimeLibraryPath(const ToolChain &TC, const ArgList &Args, ArgStringList &CmdArgs) { @@ -939,6 +958,9 @@ bool tools::addOpenMPRuntime(ArgStringList &CmdArgs, const ToolChain &TC, if (IsOffloadingHost && !Args.hasArg(options::OPT_nogpulib)) CmdArgs.push_back("-lomptarget.devicertl"); + if (IsOffloadingHost) + addOpenMPDeviceLibC(TC, Args, CmdArgs); + addArchSpecificRPath(TC, Args, CmdArgs); addOpenMPRuntimeLibraryPath(TC, Args, CmdArgs); diff --git a/clang/test/Driver/openmp-offload-gpu.c b/clang/test/Driver/openmp-offload-gpu.c index 98202d7f8e86375..d4aa9e092cf2af3 100644 --- a/clang/test/Driver/openmp-offload-gpu.c +++ b/clang/test/Driver/openmp-offload-gpu.c @@ -387,3 +387,18 @@ // RUN: | FileCheck --check-prefix=XARCH-DEVICE %s // XARCH-DEVICE: "-cc1" "-triple" "nvptx64-nvidia-cuda"{{.*}}"-O3" // XARCH-DEVICE-NOT: "-cc1" "-triple" "x86_64-unknown-linux-gnu"{{.*}}"-O3" + +// +// Check that `-gpulibc` includes the LLVM C libraries for the GPU. +// +// RUN: %clang -### --target=x86_64-unknown-linux-gnu -fopenmp=libomp \ +// RUN: --libomptarget-nvptx-bc-path=%S/Inputs/libomptarget/libomptarget-nvptx-test.bc \ +// RUN: --offload-arch=sm_52 -gpulibc -nogpuinc %s 2>&1 \ +// RUN: | FileCheck --check-prefix=LIBC-GPU %s +// LIBC-GPU: "-lcgpu"{{.*}}"-lmgpu" + +// RUN: %clang -### --target=x86_64-unknown-linux-gnu -fopenmp=libomp \ +// RUN: --libomptarget-nvptx-bc-path=%S/Inputs/libomptarget/libomptarget-nvptx-test.bc \ +// RUN: --offload-arch=sm_52 -nogpulibc -nogpuinc %s 2>&1 \ +// RUN: | FileCheck --check-prefix=NO-LIBC-GPU %s +// NO-LIBC-GPU-NOT: "-lcgpu"{{.*}}"-lmgpu" _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
