[lldb] make lit use the same PYTHONHOME for building and testing (llvm#143183)

When testing LLDB, we want to make sure to use the same Python as the
one we used to build it.

This patch used the CMake variable `Python3_ROOT_DIR` to set the
`PYTHONHOME` env variable in LLDB lit tests, in order to ensure of this.

Please see swiftlang/swift#82063 for the
original issue.

Author: charles-zablit

compiler-rt/test/lit.common.configured.in

@@ -25,6 +25,7 @@ set_default("gold_executable", "@GOLD_EXECUTABLE@")
 set_default("clang", "@COMPILER_RT_RESOLVED_TEST_COMPILER@")
 set_default("compiler_id", "@COMPILER_RT_TEST_COMPILER_ID@")
 set_default("python_executable", "@Python3_EXECUTABLE@")
+set_default("python_root_dir", "@Python3_ROOT_DIR@")
 set_default("compiler_rt_debug", @COMPILER_RT_DEBUG_PYBOOL@)
 set_default("compiler_rt_intercept_libdispatch", @COMPILER_RT_INTERCEPT_LIBDISPATCH_PYBOOL@)
 set_default("compiler_rt_output_dir", "@COMPILER_RT_RESOLVED_OUTPUT_DIR@")

lldb/test/Shell/lit.cfg.py

@@ -219,3 +219,8 @@ def calculate_arch_features(arch_string):
             config.available_features.add("ld_new-bug")
     except:
         pass
+
+# Some shell tests dynamically link with python.dll and need to know the
+# location of the Python libraries. This ensures that we use the same
+# version of Python that was used to build lldb to run our tests.
+config.environment["PYTHONHOME"] = config.python_root_dir

lldb/test/Shell/lit.site.cfg.py.in

@@ -19,6 +19,7 @@ config.python_executable = "@Python3_EXECUTABLE@"
 config.swiftc = "@LLDB_SWIFTC@"
 config.swift_libs_dir = '@LLDB_SWIFT_LIBS@'
 config.lldb_enable_swift = @LLDB_ENABLE_SWIFT_SUPPORT@
+config.python_root_dir = "@Python3_ROOT_DIR@"
 config.have_zlib = @LLVM_ENABLE_ZLIB@
 config.objc_gnustep_dir = "@LLDB_TEST_OBJC_GNUSTEP_DIR@"
 config.lldb_enable_lzma = @LLDB_ENABLE_LZMA@

lldb/test/Unit/lit.cfg.py

@@ -33,6 +33,7 @@
     ]
 )
 llvm_config.with_environment("PATH", os.path.dirname(sys.executable), append_path=True)
+config.environment["PYTHONHOME"] = config.python_root_dir
 
 # Enable sanitizer runtime flags.
 config.environment["ASAN_OPTIONS"] = "detect_stack_use_after_return=1"

lldb/test/Unit/lit.site.cfg.py.in

@@ -10,6 +10,7 @@ config.lldb_obj_root = "@LLDB_BINARY_DIR@"
 config.lldb_src_root = "@LLDB_SOURCE_DIR@"
 config.target_triple = "@LLVM_TARGET_TRIPLE@"
 config.python_executable = "@Python3_EXECUTABLE@"
+config.python_root_dir = "@Python3_ROOT_DIR@"
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)