Revert "[libc] Add support for creating wrapper headers for offloadin…

…g in clang"

This reverts commit a4a2637.

This was causing some problems with the CPU build and CUDA buildbot.
Revert until I can figure out what those issues are and fix them. I
believe it is just some CMake.

clang/lib/Driver/ToolChains/Clang.cpp

@@ -1181,30 +1181,23 @@ void Clang::AddPreprocessingOptions(Compilation &C, const JobAction &JA,
 
   // If we are compiling for a GPU target we want to override the system headers
   // with ones created by the 'libc' project if present.
+  // FIXME: We need to find a way to make these headers compatible with the
+  // host environment so they can be included from offloading languages. For now
+  // these are only active when targeting the GPU with cross-compilation.
   if (!Args.hasArg(options::OPT_nostdinc) &&
       !Args.hasArg(options::OPT_nogpuinc) &&
       !Args.hasArg(options::OPT_nobuiltininc) &&
+      C.getActiveOffloadKinds() == Action::OFK_None &&
       (getToolChain().getTriple().isNVPTX() ||
        getToolChain().getTriple().isAMDGCN())) {
 
-    // Without an offloading language we will include these headers directly.
-    // Offloading languages will instead only use the declarations stored in
-    // the resource directory at clang/lib/Headers/llvm_libc_wrappers.
-    if (C.getActiveOffloadKinds() == Action::OFK_None) {
+      // Add include/gpu-none-libc/* to our system include path. This lets us use
+      // GPU-specific system headers first.
       SmallString<128> P(llvm::sys::path::parent_path(D.InstalledDir));
       llvm::sys::path::append(P, "include");
       llvm::sys::path::append(P, "gpu-none-llvm");
       CmdArgs.push_back("-c-isystem");
       CmdArgs.push_back(Args.MakeArgString(P));
-    } else if (C.getActiveOffloadKinds() == Action::OFK_OpenMP) {
-      // TODO: CUDA / HIP include their own headers for some common functions
-      // implemented here. We'll need to clean those up so they do not conflict.
-      SmallString<128> P(D.ResourceDir);
-      llvm::sys::path::append(P, "include");
-      llvm::sys::path::append(P, "llvm_libc_wrappers");
-      CmdArgs.push_back("-internal-isystem");
-      CmdArgs.push_back(Args.MakeArgString(P));
-    }
   }
 
   // If we are offloading to a target via OpenMP we need to include the

clang/lib/Headers/CMakeLists.txt

@@ -298,14 +298,6 @@ set(openmp_wrapper_files
   openmp_wrappers/new
 )
 
-set(llvm_libc_wrapper_files
-  llvm_libc_wrappers/stdio.h
-  llvm_libc_wrappers/stdlib.h
-  llvm_libc_wrappers/string.h
-  llvm_libc_wrappers/ctype.h
-  llvm_libc_wrappers/inttypes.h
-)
-
 include(GetClangResourceDir)
 get_clang_resource_dir(output_dir PREFIX ${LLVM_LIBRARY_OUTPUT_INTDIR}/.. SUBDIR include)
 set(out_files)
@@ -341,8 +333,7 @@ endfunction(clang_generate_header)
 
 # Copy header files from the source directory to the build directory
 foreach( f ${files} ${cuda_wrapper_files} ${cuda_wrapper_bits_files}
-           ${ppc_wrapper_files} ${openmp_wrapper_files} ${hlsl_files}
-           ${llvm_libc_wrapper_files})
+           ${ppc_wrapper_files} ${openmp_wrapper_files} ${hlsl_files})
   copy_header_to_output_dir(${CMAKE_CURRENT_SOURCE_DIR} ${f})
 endforeach( f )
 
@@ -436,7 +427,6 @@ add_dependencies("clang-resource-headers"
                  "x86-resource-headers"
                  "opencl-resource-headers"
                  "openmp-resource-headers"
-                 "llvm-libc-resource-headers"
                  "windows-resource-headers"
                  "utility-resource-headers")
 
@@ -463,7 +453,6 @@ add_header_target("x86-resource-headers" "${x86_files}")
 # Other header groupings
 add_header_target("hlsl-resource-headers" ${hlsl_files})
 add_header_target("opencl-resource-headers" ${opencl_files})
-add_header_target("llvm-libc-resource-headers" ${llvm_libc_wrapper_files})
 add_header_target("openmp-resource-headers" ${openmp_wrapper_files})
 add_header_target("windows-resource-headers" ${windows_only_files})
 add_header_target("utility-resource-headers" ${utility_files})
@@ -492,11 +481,6 @@ install(
   DESTINATION ${header_install_dir}/ppc_wrappers
   COMPONENT clang-resource-headers)
 
-install(
-  FILES ${llvm_libc_wrapper_files}
-  DESTINATION ${header_install_dir}/llvm_libc_wrappers
-  COMPONENT clang-resource-headers)
-
 install(
   FILES ${openmp_wrapper_files}
   DESTINATION ${header_install_dir}/openmp_wrappers
@@ -652,12 +636,6 @@ install(
   EXCLUDE_FROM_ALL
   COMPONENT openmp-resource-headers)
 
-install(
-  FILES ${openmp_wrapper_files}
-  DESTINATION ${header_install_dir}/openmp_wrappers
-  EXCLUDE_FROM_ALL
-  COMPONENT openmp-resource-headers)
-
 install(
   FILES ${utility_files}
   DESTINATION ${header_install_dir}

clang/test/Driver/gpu-libc-headers.c

@@ -1,14 +1,6 @@
 // REQUIRES: nvptx-registered-target
 // REQUIRES: amdgpu-registered-target
 
-// RUN:   %clang -### --target=x86_64-unknown-linux-gnu -fopenmp=libomp --sysroot=./ \
-// RUN:     -fopenmp-targets=amdgcn-amd-amdhsa -Xopenmp-target=amdgcn-amd-amdhsa --offload-arch=gfx908  \
-// RUN:     -nogpulib %s 2>&1 | FileCheck %s --check-prefix=CHECK-HEADERS
-// RUN:   %clang -### --target=x86_64-unknown-linux-gnu -fopenmp=libomp --sysroot=./ \
-// RUN:     -fopenmp-targets=nvptx64-nvidia-cuda -Xopenmp-target=nvptx64-nvidia-cuda --offload-arch=sm_70  \
-// RUN:     -nogpulib %s 2>&1 | FileCheck %s --check-prefix=CHECK-HEADERS
-// CHECK-HEADERS: "-cc1"{{.*}}"-internal-isystem" "{{.*}}include{{.*}}llvm_libc_wrappers"{{.*}}"-isysroot" "./"
-
 // RUN:   %clang -### --target=amdgcn-amd-amdhsa -mcpu=gfx1030 -nogpulib \
 // RUN:     -nogpuinc %s 2>&1 | FileCheck %s --check-prefix=CHECK-HEADERS-DISABLED
 // RUN:   %clang -### --target=amdgcn-amd-amdhsa -mcpu=gfx1030 -nogpulib \