[CMake] Remove unused variable LLDB_TEST_CXX_COMPILER

CMake allows you to set a custom CXX compiler for the API test suite.
However, this variable is never used, because dotest uses the same
compiler to build C and CXX sources.

I'm not sure if this variable was added with the intention of supporting
a different compiler or if this is just a remnant of old functionality.
Given that this hasn't been working for a while, I assume it's safe to
remove.

Differential revision: https://reviews.llvm.org/D69401

lldb/CMakeLists.txt

@@ -91,22 +91,18 @@ if(LLDB_INCLUDE_TESTS)
   set(LLDB_DEFAULT_TEST_FILECHECK "${LLVM_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/FileCheck${CMAKE_EXECUTABLE_SUFFIX}")
 
   if (TARGET clang)
-    set(LLDB_DEFAULT_TEST_C_COMPILER "${LLVM_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/clang${CMAKE_EXECUTABLE_SUFFIX}")
-    set(LLDB_DEFAULT_TEST_CXX_COMPILER "${LLVM_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/clang++${CMAKE_EXECUTABLE_SUFFIX}")
+    set(LLDB_DEFAULT_TEST_COMPILER "${LLVM_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin/clang${CMAKE_EXECUTABLE_SUFFIX}")
   else()
-    set(LLDB_DEFAULT_TEST_C_COMPILER "")
-    set(LLDB_DEFAULT_TEST_CXX_COMPILER "")
+    set(LLDB_DEFAULT_TEST_COMPILER "")
   endif()
 
   set(LLDB_TEST_EXECUTABLE "${LLDB_DEFAULT_TEST_EXECUTABLE}" CACHE PATH "lldb executable used for testing")
-  set(LLDB_TEST_C_COMPILER "${LLDB_DEFAULT_TEST_C_COMPILER}" CACHE PATH "C Compiler to use for building LLDB test inferiors")
-  set(LLDB_TEST_CXX_COMPILER "${LLDB_DEFAULT_TEST_CXX_COMPILER}" CACHE PATH "C++ Compiler to use for building LLDB test inferiors")
+  set(LLDB_TEST_COMPILER "${LLDB_DEFAULT_TEST_COMPILER}" CACHE PATH "C Compiler to use for building LLDB test inferiors")
   set(LLDB_TEST_DSYMUTIL "${LLDB_DEFAULT_TEST_DSYMUTIL}" CACHE PATH "dsymutil used for generating dSYM bundles")
   set(LLDB_TEST_FILECHECK "${LLDB_DEFAULT_TEST_FILECHECK}" CACHE PATH "FileCheck used for testing purposes")
 
-  if (("${LLDB_TEST_C_COMPILER}" STREQUAL "") OR
-      ("${LLDB_TEST_CXX_COMPILER}" STREQUAL ""))
-    message(FATAL_ERROR "LLDB test compilers not specified. Tests will not run.")
+  if ("${LLDB_TEST_COMPILER}" STREQUAL "")
+    message(FATAL_ERROR "LLDB test compiler not specified. Tests will not run.")
   endif()
 
   add_custom_target(lldb-test-deps)

lldb/docs/resources/build.rst

@@ -186,8 +186,7 @@ suite.
 ::
 
   > cmake -G Ninja \
-      -DLLDB_TEST_C_COMPILER=<path to C compiler> \
-      -DLLDB_TEST_CXX_COMPILER=<path to C++ compiler> \
+      -DLLDB_TEST_COMPILER=<path to C compiler> \
       <path to root of llvm source tree>
 
 It is strongly recommend to use a release build for the compiler to speed up
@@ -227,7 +226,7 @@ Sample command line:
   > cmake -G Ninja^
       -DLLDB_TEST_DEBUG_TEST_CRASHES=1^
       -DPYTHON_HOME=C:\Python35^
-      -DLLDB_TEST_C_COMPILER=d:\src\llvmbuild\ninja_release\bin\clang.exe^
+      -DLLDB_TEST_COMPILER=d:\src\llvmbuild\ninja_release\bin\clang.exe^
       <path to root of llvm source tree>
 
 

lldb/docs/resources/test.rst

@@ -42,8 +42,7 @@ target.
 
 By default, the ``check-lldb`` target builds the test programs with the same
 compiler that was used to build LLDB. To build the tests with a different
-compiler, you can set the ``LLDB_TEST_C_COMPILER`` or the
-``LLDB_TEST_CXX_COMPILER`` CMake variables.
+compiler, you can set the ``LLDB_TEST_COMPILER`` CMake variable.
 
 It is possible to customize the architecture of the test binaries and compiler
 used by appending ``-A`` and ``-C`` options respectively to the CMake variable

lldb/test/API/CMakeLists.txt

@@ -48,7 +48,7 @@ list(APPEND LLDB_TEST_COMMON_ARGS
   --executable ${LLDB_TEST_EXECUTABLE}
   --dsymutil ${LLDB_TEST_DSYMUTIL}
   --filecheck ${LLDB_TEST_FILECHECK}
-  -C ${LLDB_TEST_C_COMPILER}
+  --compiler ${LLDB_TEST_COMPILER}
   )
 
 if ( CMAKE_SYSTEM_NAME MATCHES "Windows" )