[lldb] Use the Python limited API with SWIG 4.2 or later (#153119)

[JDevlieghere]

Use the Python limited API when building with SWIG 4.2 or later.

[llvmbot]

@llvm/pr-subscribers-lldb

Author: Jonas Devlieghere (JDevlieghere)

Changes

Use the Python limited API when building with SWIG 4.2 or later.

---

Full diff: https://github.com/llvm/llvm-project/pull/153472.diff

1 Files Affected:

• (modified) lldb/cmake/modules/LLDBConfig.cmake (+9-1)

diff --git a/lldb/cmake/modules/LLDBConfig.cmake b/lldb/cmake/modules/LLDBConfig.cmake
index a9679d63e010d..c65c7e24badd9 100644
--- a/lldb/cmake/modules/LLDBConfig.cmake
+++ b/lldb/cmake/modules/LLDBConfig.cmake
@@ -68,7 +68,6 @@ add_optional_dependency(LLDB_ENABLE_FBSDVMCORE "Enable libfbsdvmcore support in
 option(LLDB_USE_ENTITLEMENTS "When codesigning, use entitlements if available" ON)
 option(LLDB_BUILD_FRAMEWORK "Build LLDB.framework (Darwin only)" OFF)
 option(LLDB_ENABLE_PROTOCOL_SERVERS "Enable protocol servers (e.g. MCP) in LLDB" ON)
-option(LLDB_ENABLE_PYTHON_LIMITED_API "Force LLDB to only use the Python Limited API (requires SWIG 4.2 or later)" OFF)
 option(LLDB_NO_INSTALL_DEFAULT_RPATH "Disable default RPATH settings in binaries" OFF)
 option(LLDB_USE_SYSTEM_DEBUGSERVER "Use the system's debugserver for testing (Darwin only)." OFF)
 option(LLDB_SKIP_STRIP "Whether to skip stripping of binaries when installing lldb." OFF)
@@ -174,11 +173,20 @@ if (LLDB_ENABLE_PYTHON)
     ${default_embed_python_home})
 
   include_directories(${Python3_INCLUDE_DIRS})
+
   if (LLDB_EMBED_PYTHON_HOME)
     get_filename_component(PYTHON_HOME "${Python3_EXECUTABLE}" DIRECTORY)
     set(LLDB_PYTHON_HOME "${PYTHON_HOME}" CACHE STRING
       "Path to use as PYTHONHOME in lldb. If a relative path is specified, it will be resolved at runtime relative to liblldb directory.")
   endif()
+
+  if (SWIG_VERSION VERSION_GREATER_EQUAL "4.2" AND NOT LLDB_EMBED_PYTHON_HOME)
+    set(default_enable_python_limited_api ON)
+  else()
+    set(default_enable_python_limited_api OFF)
+  endif()
+  option(LLDB_ENABLE_PYTHON_LIMITED_API "Force LLDB to only use the Python Limited API (requires SWIG 4.2 or later)"
+    ${default_enable_python_limited_api})
 endif()
 
 if (LLVM_EXTERNAL_CLANG_SOURCE_DIR)

[JDevlieghere]

This is a re-land of #153119 but this time correctly accounting for LLDB_EMBED_PYTHON_HOME.

Blocked on #153329 and #153460.

[JDevlieghere]

Let's try this again