[lldb] fix -print-script-interpreter-info on windows

Apparently "{sys.prefix}/bin/python3" isn't where you find the
python interpreter on windows, so the test I wrote for
-print-script-interpreter-info is failing.

We can't rely on sys.executable at runtime, because that will point
to lldb.exe not python.exe.

We can't just record sys.executable from build time, because python
could have been moved to a different location.

But it should be OK to apply relative path from sys.prefix to sys.executable
from build-time to the sys.prefix at runtime.

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D113650

1 files changed, 22 insertions, 18 deletions

diff --git a/lldb/CMakeLists.txt b/lldb/CMakeLists.txt
index 028dadbb8c73..1a54addf3d55 100644
--- a/lldb/CMakeLists.txt
+++ b/lldb/CMakeLists.txt
@@ -31,24 +31,28 @@ if (WIN32)
 endif()
 
 if (LLDB_ENABLE_PYTHON)
-  if (NOT CMAKE_CROSSCOMPILING)
-    execute_process(
-      COMMAND ${Python3_EXECUTABLE}
-          -c "import distutils.sysconfig; print(distutils.sysconfig.get_python_lib(True, False, ''))"
-      OUTPUT_VARIABLE LLDB_PYTHON_DEFAULT_RELATIVE_PATH
-      OUTPUT_STRIP_TRAILING_WHITESPACE)
-
-    file(TO_CMAKE_PATH ${LLDB_PYTHON_DEFAULT_RELATIVE_PATH} LLDB_PYTHON_DEFAULT_RELATIVE_PATH)
-  else ()
-    if ("${LLDB_PYTHON_RELATIVE_PATH}" STREQUAL "")
-      message(FATAL_ERROR
-        "Crosscompiling LLDB with Python requires manually setting
-        LLDB_PYTHON_RELATIVE_PATH.")
-    endif ()
-  endif ()
-
-  set(LLDB_PYTHON_RELATIVE_PATH ${LLDB_PYTHON_DEFAULT_RELATIVE_PATH}
-    CACHE STRING "Path where Python modules are installed, relative to install prefix")
+  set(cachestring_LLDB_PYTHON_RELATIVE_PATH
+    "Path where Python modules are installed, relative to install prefix")
+  set(cachestring_LLDB_PYTHON_EXE_RELATIVE_PATH
+    "Path to python interpreter exectuable, relative to install prefix")
+
+  foreach(var LLDB_PYTHON_RELATIVE_PATH LLDB_PYTHON_EXE_RELATIVE_PATH)
+    if(NOT DEFINED ${var} AND NOT CMAKE_CROSSCOMPILING)
+      execute_process(
+        COMMAND ${Python3_EXECUTABLE}
+          ${CMAKE_CURRENT_SOURCE_DIR}/bindings/python/get-python-config.py
+          ${var}
+        OUTPUT_VARIABLE value
+        OUTPUT_STRIP_TRAILING_WHITESPACE)
+      file(TO_CMAKE_PATH "${value}" value)
+      set(${var} ${value} CACHE STRING ${cachestring_${var}})
+    else()
+      if ("${${var}}" STREQUAL "")
+        message(FATAL_ERROR
+          "Crosscompiling LLDB with Python requires manually setting ${var}.")
+      endif()
+    endif()
+  endforeach()
 endif ()
 
 if (LLDB_ENABLE_LUA)