From b26970ec4b79590f41f5e1dd7cb56d5f8d4d9301 Mon Sep 17 00:00:00 2001
From: Joseph Huber <jhuber6@vols.utk.edu>
Date: Fri, 24 Mar 2023 21:00:25 -0500
Subject: [PATCH] [libc] Enable integration tests targeting NVIDIA GPUs

This patch adds the necessary build infrastructure to build and run the
integration tests on NVIDIA GPUs. The NVIDIA `nvlink` linker utility is
what is ultimately used to combine these files into a single executable
image. Unfortunately, their tool does not support static libraries. So
we need to link with every object directly instead. This could be solved
by impelementing a "wrapper" utility around `nvlink` like we used to use
for OpenMP. But for now this should be sufficient.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D146861
---
 libc/cmake/modules/LLVMLibCTestRules.cmake | 11 ++++++++---
 libc/utils/gpu/loader/CMakeLists.txt       |  8 ++++++++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/libc/cmake/modules/LLVMLibCTestRules.cmake b/libc/cmake/modules/LLVMLibCTestRules.cmake
index f28b345..4e1a63d 100644
--- a/libc/cmake/modules/LLVMLibCTestRules.cmake
+++ b/libc/cmake/modules/LLVMLibCTestRules.cmake
@@ -484,6 +484,8 @@ function(add_integration_test test_name)
   add_executable(
     ${fq_build_target_name}
     EXCLUDE_FROM_ALL
+    # The NVIDIA 'nvlink' linker does not currently support static libraries.
+    $<$<BOOL:${LIBC_TARGET_ARCHITECTURE_IS_GPU}>:${link_object_files}>
     ${INTEGRATION_TEST_SRCS}
     ${INTEGRATION_TEST_HDRS}
   )
@@ -510,9 +512,12 @@ function(add_integration_test test_name)
   endif()
 
   target_link_options(${fq_build_target_name} PRIVATE -nostdlib -static)
-  target_link_libraries(${fq_build_target_name} ${fq_target_name}.__libc__
-                        libc.startup.${LIBC_TARGET_OS}.crt1
-                        libc.test.IntegrationTest.test)
+  target_link_libraries(
+    ${fq_build_target_name}
+    # The NVIDIA 'nvlink' linker does not currently support static libraries.
+    $<$<NOT:$<BOOL:${LIBC_TARGET_ARCHITECTURE_IS_GPU}>>:${fq_target_name}.__libc__>
+    libc.startup.${LIBC_TARGET_OS}.crt1
+    libc.test.IntegrationTest.test)
   add_dependencies(${fq_build_target_name}
                    libc.test.IntegrationTest.test
                    ${INTEGRATION_TEST_DEPENDS})
diff --git a/libc/utils/gpu/loader/CMakeLists.txt b/libc/utils/gpu/loader/CMakeLists.txt
index 5e9f0a1..f037d3f 100644
--- a/libc/utils/gpu/loader/CMakeLists.txt
+++ b/libc/utils/gpu/loader/CMakeLists.txt
@@ -24,4 +24,12 @@ if(TARGET amdhsa_loader AND LIBC_GPU_TARGET_ARCHITECTURE_IS_AMDGPU)
     PROPERTIES
       EXECUTABLE "$<TARGET_FILE:amdhsa_loader>"
   )
+elseif(TARGET nvptx_loader AND LIBC_GPU_TARGET_ARCHITECTURE_IS_NVPTX)
+  add_custom_target(libc.utils.gpu.loader)
+  add_dependencies(libc.utils.gpu.loader nvptx_loader)
+  set_target_properties(
+    libc.utils.gpu.loader
+    PROPERTIES
+      EXECUTABLE "$<TARGET_FILE:nvptx_loader>"
+  )
 endif()
-- 
2.7.4