[xray] [tests] Detect and handle missing LLVMTestingSupport gracefully

Add a code to properly test for presence of LLVMTestingSupport library
when performing a stand-alone build, and skip tests requiring it when
it is not present.  Since the library is not installed, llvm-config
reported empty --libs for it and the tests failed to link with undefined
references.  Skipping the two fdr_* test files is better than failing to
build, and should be good enough until we find a better solution.

NB: both installing LLVMTestingSupport and building it automatically
from within compiler-rt sources are non-trivial.  The former due to
dependency on gtest, the latter due to tight integration with LLVM
source tree.

Differential Revision: https://reviews.llvm.org/D55891

llvm-svn: 349899

compiler-rt/cmake/Modules/CompilerRTUtils.cmake

@@ -239,7 +239,7 @@ macro(load_llvm_config)
     # Detect if we have the LLVMXRay and TestingSupport library installed and
     # available from llvm-config.
     execute_process(
-      COMMAND ${LLVM_CONFIG_PATH} "--ldflags" "--libs" "xray" "testingsupport"
+      COMMAND ${LLVM_CONFIG_PATH} "--ldflags" "--libs" "xray"
       RESULT_VARIABLE HAD_ERROR
       OUTPUT_VARIABLE CONFIG_OUTPUT)
     if (HAD_ERROR)
@@ -254,6 +254,26 @@ macro(load_llvm_config)
       set(COMPILER_RT_HAS_LLVMXRAY TRUE)
     endif()
 
+    set(COMPILER_RT_HAS_LLVMTESTINGSUPPORT FALSE)
+    execute_process(
+      COMMAND ${LLVM_CONFIG_PATH} "--ldflags" "--libs" "testingsupport"
+      RESULT_VARIABLE HAD_ERROR
+      OUTPUT_VARIABLE CONFIG_OUTPUT)
+    if (HAD_ERROR)
+      message(WARNING "llvm-config finding testingsupport failed with status ${HAD_ERROR}")
+    else()
+      string(REGEX REPLACE "[ \t]*[\r\n]+[ \t]*" ";" CONFIG_OUTPUT ${CONFIG_OUTPUT})
+      list(GET CONFIG_OUTPUT 0 LDFLAGS)
+      list(GET CONFIG_OUTPUT 1 LIBLIST)
+      if (LIBLIST STREQUAL "")
+        message(WARNING "testingsupport library not installed, some tests will be skipped")
+      else()
+        set(LLVM_TESTINGSUPPORT_LDFLAGS ${LDFLAGS} CACHE STRING "Linker flags for LLVMTestingSupport library")
+        set(LLVM_TESTINGSUPPORT_LIBLIST ${LIBLIST} CACHE STRING "Library list for LLVMTestingSupport")
+        set(COMPILER_RT_HAS_LLVMTESTINGSUPPORT TRUE)
+      endif()
+    endif()
+
     # Make use of LLVM CMake modules.
     # --cmakedir is supported since llvm r291218 (4.0 release)
     execute_process(

compiler-rt/lib/xray/tests/CMakeLists.txt

@@ -60,6 +60,10 @@ if (NOT APPLE)
   if (COMPILER_RT_STANDALONE_BUILD)
     append_list_if(COMPILER_RT_HAS_LLVMXRAY ${LLVM_XRAY_LDFLAGS} XRAY_UNITTEST_LINK_FLAGS)
     append_list_if(COMPILER_RT_HAS_LLVMXRAY ${LLVM_XRAY_LIBLIST} XRAY_UNITTEST_LINK_FLAGS)
+    append_list_if(COMPILER_RT_HAS_LLVMTESTINGSUPPORT
+      ${LLVM_TESTINGSUPPORT_LDFLAGS} XRAY_UNITTEST_LINK_FLAGS)
+    append_list_if(COMPILER_RT_HAS_LLVMTESTINGSUPPORT
+      ${LLVM_TESTINGSUPPORT_LIBLIST} XRAY_UNITTEST_LINK_FLAGS)
   else()
     # We add the library directories one at a time in our CFLAGS.
     foreach (DIR ${LLVM_LIBRARY_DIR})

compiler-rt/lib/xray/tests/unit/CMakeLists.txt

@@ -1,10 +1,16 @@
-add_xray_unittest(XRayTest SOURCES
+set(TEST_SOURCES
   allocator_test.cc
   buffer_queue_test.cc
-  fdr_controller_test.cc
-  fdr_log_writer_test.cc
   function_call_trie_test.cc
   profile_collector_test.cc
   segmented_array_test.cc
   test_helpers.cc
   xray_unit_test_main.cc)
+
+if (NOT COMPILER_RT_STANDALONE_BUILD OR COMPILER_RT_HAS_LLVMTESTINGSUPPORT)
+  list(APPEND TEST_SOURCES
+    fdr_controller_test.cc
+    fdr_log_writer_test.cc)
+endif()
+
+add_xray_unittest(XRayTest SOURCES ${TEST_SOURCES})