[libc] Fix the GPU build when building inside the NATIVE project

[jhuber6]

Summary:
We use the NATIVE directory for cross-compiling tools that need to be
run on the host. This was not forwarding the CMake arguments we used to
check if this was a GPU compile that created its own tools. Forward that
and simplify.

Fixes #118558

[llvmbot]

@llvm/pr-subscribers-libc

Author: Joseph Huber (jhuber6)

Changes

Summary:
We use the NATIVE directory for cross-compiling tools that need to be
run on the host. This was not forwarding the CMake arguments we used to
check if this was a GPU compile that created its own tools. Forward that
and simplify.

Fixes #118558

---

Full diff: https://github.com/llvm/llvm-project/pull/118573.diff

2 Files Affected:

• (modified) libc/CMakeLists.txt (+3-16)
• (modified) llvm/cmake/modules/CrossCompile.cmake (+3)

diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index fd82359022cffd..11a355b1203602 100644
--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@@ -52,22 +52,9 @@ set(LIBC_NAMESPACE ${default_namespace}
 
 # We will build the GPU utilities if we are not doing a runtimes build.
 option(LIBC_BUILD_GPU_LOADER "Always build the GPU loader utilities" OFF)
-if(LIBC_BUILD_GPU_LOADER OR NOT LLVM_RUNTIMES_BUILD)
-  foreach(_name ${LLVM_RUNTIME_TARGETS})
-    if("libc" IN_LIST RUNTIMES_${_name}_LLVM_ENABLE_RUNTIMES)
-      if("${_name}" STREQUAL "amdgcn-amd-amdhsa" OR "${_name}" STREQUAL "nvptx64-nvidia-cuda")
-        set(LIBC_NEED_LOADER_UTILS TRUE)
-      endif()
-    endif()
-  endforeach()
-  if("${LIBC_TARGET_TRIPLE}" STREQUAL "amdgcn-amd-amdhsa" OR
-     "${LIBC_TARGET_TRIPLE}" STREQUAL "nvptx64-nvidia-cuda")
-    set(LIBC_NEED_LOADER_UTILS TRUE)
-  endif()
-  if(LIBC_NEED_LOADER_UTILS)
-    add_subdirectory(utils/gpu)
-    return()
-  endif()
+if(LIBC_BUILD_GPU_LOADER OR ((NOT LLVM_RUNTIMES_BUILD) AND LLVM_LIBC_GPU_BUILD))
+  add_subdirectory(utils/gpu)
+  return()
 endif()
 
 add_subdirectory(newhdrgen)
diff --git a/llvm/cmake/modules/CrossCompile.cmake b/llvm/cmake/modules/CrossCompile.cmake
index e36a71f522d82c..c22d185349dcc5 100644
--- a/llvm/cmake/modules/CrossCompile.cmake
+++ b/llvm/cmake/modules/CrossCompile.cmake
@@ -78,6 +78,9 @@ function(llvm_create_cross_target project_name target_name toolchain buildtype)
       list(APPEND libc_flags -DLLVM_FORCE_BUILD_RUNTIME=ON)
     endif()
   endif()
+  if(LLVM_LIBC_GPU_BUILD)
+    list(APPEND libc_flags -DLLVM_LIBC_GPU_BUILD=ON)
+  endif()
 
   add_custom_command(OUTPUT ${${project_name}_${target_name}_BUILD}/CMakeCache.txt
     COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}"

[nickdesaulniers]

Thanks for figuring this out!

Looks like there's some more references to LIBC_HDRGEN_EXE in llvm/cmake/modules/CrossCompile.cmake that can get cleaned up, too.

[jhuber6]

Not that this makes GPU build + project libc build not work, but I'm not too concerened because we're deprecating that anyways.

[llvm-ci]

LLVM Buildbot has detected a new failure on builder lld-x86_64-win running on as-worker-93 while building libc,llvm at step 7 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/146/builds/1763

Here is the relevant piece of the build log for the reference

Step 7 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM-Unit :: Support/./SupportTests.exe/37/87' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:C:\a\lld-x86_64-win\build\unittests\Support\.\SupportTests.exe-LLVM-Unit-14912-37-87.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=87 GTEST_SHARD_INDEX=37 C:\a\lld-x86_64-win\build\unittests\Support\.\SupportTests.exe
--

Script:
--
C:\a\lld-x86_64-win\build\unittests\Support\.\SupportTests.exe --gtest_filter=ProgramEnvTest.CreateProcessLongPath
--
C:\a\lld-x86_64-win\llvm-project\llvm\unittests\Support\ProgramTest.cpp(160): error: Expected equality of these values:
  0
  RC
    Which is: -2

C:\a\lld-x86_64-win\llvm-project\llvm\unittests\Support\ProgramTest.cpp(163): error: fs::remove(Twine(LongPath)): did not return errc::success.
error number: 13
error message: permission denied



C:\a\lld-x86_64-win\llvm-project\llvm\unittests\Support\ProgramTest.cpp:160
Expected equality of these values:
  0
  RC
    Which is: -2

C:\a\lld-x86_64-win\llvm-project\llvm\unittests\Support\ProgramTest.cpp:163
fs::remove(Twine(LongPath)): did not return errc::success.
error number: 13
error message: permission denied




********************