[libc] Add hooks for extra options in running hermetic tests

[saturn691]

These hooks are required downstream in order to run hermetic tests. I'm not too sure about the specifics about this PR, it's quite rough, but if you're happy we can get started with hermetic testing downstream.

See arm/arm-toolchain#420 for more context on how this PR will be used.

Closes #145349. This is the final PR to get minimal functionality.

[llvmbot]

@llvm/pr-subscribers-libc

Author: William Huynh (saturn691)

Changes

These hooks are required downstream in order to run hermetic tests. I'm not too sure about the specifics about this PR, it's quite rough, but if you're happy we can get started with hermetic testing downstream.

See arm/arm-toolchain#420 for more context on how this PR will be used.

Closes #145349. This is the final PR to get minimal functionality.

---

Full diff: https://github.com/llvm/llvm-project/pull/147931.diff

1 Files Affected:

• (modified) libc/cmake/modules/LLVMLibCTestRules.cmake (+20-5)

diff --git a/libc/cmake/modules/LLVMLibCTestRules.cmake b/libc/cmake/modules/LLVMLibCTestRules.cmake
index 1cd09816e223f..739fd6639a976 100644
--- a/libc/cmake/modules/LLVMLibCTestRules.cmake
+++ b/libc/cmake/modules/LLVMLibCTestRules.cmake
@@ -288,7 +288,9 @@ function(create_libc_unittest fq_target_name)
   target_include_directories(${fq_build_target_name} SYSTEM PRIVATE ${LIBC_INCLUDE_DIR})
   target_include_directories(${fq_build_target_name} PRIVATE ${LIBC_SOURCE_DIR})
   target_compile_options(${fq_build_target_name} PRIVATE ${compile_options})
-  target_link_options(${fq_build_target_name} PRIVATE ${link_options})
+  
+  string(REPLACE " " ";" EXTRA_LINK_OPTIONS "${LIBC_TEST_EXTRA_LINK_OPTIONS}")
+  target_link_options(${fq_build_target_name} PRIVATE ${link_options} ${EXTRA_LINK_OPTIONS})
 
   if(NOT LIBC_UNITTEST_CXX_STANDARD)
     set(LIBC_UNITTEST_CXX_STANDARD ${CMAKE_CXX_STANDARD})
@@ -580,7 +582,9 @@ function(add_integration_test test_name)
       -march=${LIBC_GPU_TARGET_ARCHITECTURE} -nostdlib -static
       "--cuda-path=${LIBC_CUDA_ROOT}")
   elseif(LIBC_CC_SUPPORTS_NOSTDLIBPP)
-    target_link_options(${fq_build_target_name} PRIVATE -nolibc -nostartfiles -nostdlib++ -static)
+    string(REPLACE " " ";" EXTRA_LINK_OPTIONS "${LIBC_TEST_EXTRA_LINK_OPTIONS}")
+    target_link_options(${fq_build_target_name} PRIVATE
+      -nolibc -nostartfiles -nostdlib++ -static ${EXTRA_LINK_OPTIONS})
   else()
     # Older version of gcc does not support `nostdlib++` flag.  We use
     # `nostdlib` and link against libgcc_s, which cannot be linked statically.
@@ -774,7 +778,9 @@ function(add_libc_hermetic test_name)
       -march=${LIBC_GPU_TARGET_ARCHITECTURE} -nostdlib -static
       "--cuda-path=${LIBC_CUDA_ROOT}")
   elseif(LIBC_CC_SUPPORTS_NOSTDLIBPP)
-    target_link_options(${fq_build_target_name} PRIVATE -nolibc -nostartfiles -nostdlib++ -static)
+    string(REPLACE " " ";" EXTRA_LINK_OPTIONS "${LIBC_TEST_EXTRA_LINK_OPTIONS}")
+    target_link_options(${fq_build_target_name} PRIVATE 
+      -nolibc -nostartfiles -nostdlib++ -static ${EXTRA_LINK_OPTIONS})
   else()
     # Older version of gcc does not support `nostdlib++` flag.  We use
     # `nostdlib` and link against libgcc_s, which cannot be linked statically.
@@ -809,9 +815,16 @@ function(add_libc_hermetic test_name)
   endif()
 
   if(NOT HERMETIC_TEST_NO_RUN_POSTBUILD)
-    set(test_cmd ${HERMETIC_TEST_ENV}
+    if (LIBC_TEST_CMD)
+      # In the form of "<command> binary=@BINARY@", e.g. "qemu-system-arm -loader$<COMMA>file=@BINARY@"
+      string(REPLACE "@BINARY@" "$<TARGET_FILE:${fq_build_target_name}>" test_cmd_parsed ${LIBC_TEST_CMD})
+      string(REPLACE " " ";" test_cmd "${test_cmd_parsed}")
+    else()
+      set(test_cmd ${HERMETIC_TEST_ENV}
         $<$<BOOL:${LIBC_TARGET_OS_IS_GPU}>:${gpu_loader_exe}> ${CMAKE_CROSSCOMPILING_EMULATOR} ${HERMETIC_TEST_LOADER_ARGS}
         $<TARGET_FILE:${fq_build_target_name}> ${HERMETIC_TEST_ARGS})
+    endif()
+
     add_custom_target(
       ${fq_target_name}
       DEPENDS ${fq_target_name}.__cmd__
@@ -863,7 +876,9 @@ function(add_libc_test test_name)
       # Tests like the file tests perform file operations on disk file. If we
       # don't chain up the unit test and hermetic test, then those tests will
       # step on each other's files.
-      add_dependencies(${fq_test_name}.__hermetic__ ${fq_test_name}.__unit__)
+      if(NOT LIBC_TEST_HERMETIC_ONLY)
+        add_dependencies(${fq_test_name}.__hermetic__ ${fq_test_name}.__unit__)
+      endif()
     endif()
   endif()
 endfunction(add_libc_test)

[lntue]

We already have LIBC_COMPILE_OPTIONS_DEFAULT and LIBC_TEST_COMPILE_OPTIONS_DEFAULT. Does it work for you, or a separate linking flag is actually needed? If so can we add LIBC_LINK_OPTIONS_DEFAULT and LIBC_TEST_LINK_OPTIONS_DEFAULT similar to the compile option flags?

[saturn691]

Yes, that should work for me. I'll get to work on it next week, we may need to keep the string replace due to way our build system uses ExternalProject_Add.