[lldb] Use PY_VERSION_HEX to simplify conditional compilation (NFC)

[JDevlieghere]

Use PY_VERSION_HEX to simplify conditional compilation depending on the Python version.

This also adds a static_assert to lldb-python to error out with a meaningful diagnostic when you try building LLDB with an older Python version in preparation for [1].

[1] https://discourse.llvm.org/t/rfc-lets-document-and-enforce-a-minimum-python-version-for-lldb/82731/15

[llvmbot]

@llvm/pr-subscribers-lldb

Author: Jonas Devlieghere (JDevlieghere)

Changes

Use PY_VERSION_HEX to simplify conditional compilation depending on the Python version.

This also adds a static_assert to lldb-python to error out with a meaningful diagnostic when you try building LLDB with an older Python version in preparation for [1].

[1] https://discourse.llvm.org/t/rfc-lets-document-and-enforce-a-minimum-python-version-for-lldb/82731/15

---

Full diff: https://github.com/llvm/llvm-project/pull/114346.diff

4 Files Affected:

• (modified) lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp (+6-6)
• (modified) lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp (+8-9)
• (modified) lldb/source/Plugins/ScriptInterpreter/Python/lldb-python.h (+4)
• (modified) lldb/unittests/ScriptInterpreter/Python/PythonDataObjectsTests.cpp (+1-1)

diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
index 90ccd1055199a0..a0f8cf954f8040 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
@@ -71,12 +71,12 @@ Expected<std::string> python::As<std::string>(Expected<PythonObject> &&obj) {
 }
 
 static bool python_is_finalizing() {
-#if (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 13) || (PY_MAJOR_VERSION > 3)
+#if PY_VERSION_HEX >= 0x030d0000
   return Py_IsFinalizing();
-#elif PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 7
-  return _Py_Finalizing != nullptr;
-#else
+#elif PY_VERSION_HEX >= 0x03070000
   return _Py_IsFinalizing();
+#else
+  return _Py_Finalizing != nullptr;
 #endif
 }
 
@@ -810,7 +810,7 @@ bool PythonCallable::Check(PyObject *py_obj) {
   return PyCallable_Check(py_obj);
 }
 
-#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 3
+#if PY_VERSION_HEX >= 0x03030000
 static const char get_arg_info_script[] = R"(
 from inspect import signature, Parameter, ismethod
 from collections import namedtuple
@@ -839,7 +839,7 @@ Expected<PythonCallable::ArgInfo> PythonCallable::GetArgInfo() const {
   if (!IsValid())
     return nullDeref();
 
-#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 3
+#if PY_VERSION_HEX >= 0x03030000
 
   // no need to synchronize access to this global, we already have the GIL
   static PythonScript get_arg_info(get_arg_info_script);
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
index 7c2b6517468ff4..ef3c53ca5698db 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
@@ -71,8 +71,7 @@ extern "C" PyObject *PyInit__lldb(void);
 #define LLDB_USE_PYTHON_SET_INTERRUPT 0
 #else
 // PyErr_SetInterrupt was introduced in 3.2.
-#define LLDB_USE_PYTHON_SET_INTERRUPT                                          \
-  (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 2) || (PY_MAJOR_VERSION > 3)
+#define LLDB_USE_PYTHON_SET_INTERRUPT PY_VERSION_HEX >= 0x03020000
 #endif
 
 static ScriptInterpreterPythonImpl *GetPythonInterpreter(Debugger &debugger) {
@@ -92,7 +91,7 @@ namespace {
 struct InitializePythonRAII {
 public:
   InitializePythonRAII() {
-#if (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 8) || (PY_MAJOR_VERSION > 3)
+#if PY_VERSION_HEX >= 0x03080000
     PyConfig config;
     PyConfig_InitPythonConfig(&config);
 #endif
@@ -109,7 +108,7 @@ struct InitializePythonRAII {
       return spec.GetPath();
     }();
     if (!g_python_home.empty()) {
-#if (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 8) || (PY_MAJOR_VERSION > 3)
+#if PY_VERSION_HEX >= 0x03080000
       PyConfig_SetBytesString(&config, &config.home, g_python_home.c_str());
 #else
       size_t size = 0;
@@ -143,7 +142,7 @@ struct InitializePythonRAII {
       PyImport_AppendInittab("_lldb", LLDBSwigPyInit);
     }
 
-#if (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 8) || (PY_MAJOR_VERSION > 3)
+#if PY_VERSION_HEX >= 0x03080000
     config.install_signal_handlers = 0;
     Py_InitializeFromConfig(&config);
     PyConfig_Clear(&config);
@@ -152,7 +151,7 @@ struct InitializePythonRAII {
 // Python < 3.2 and Python >= 3.2 reversed the ordering requirements for
 // calling `Py_Initialize` and `PyEval_InitThreads`.  < 3.2 requires that you
 // call `PyEval_InitThreads` first, and >= 3.2 requires that you call it last.
-#if (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 2)
+#if PY_VERSION_HEX >= 0x03020000
     Py_InitializeEx(0);
     InitializeThreadsPrivate();
 #else
@@ -182,7 +181,7 @@ struct InitializePythonRAII {
 // would always return `true` and `PyGILState_Ensure/Release` flow would be
 // executed instead of unlocking GIL with `PyEval_SaveThread`. When
 // an another thread calls `PyGILState_Ensure` it would get stuck in deadlock.
-#if (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 7) || (PY_MAJOR_VERSION > 3)
+#if PY_VERSION_HEX >= 0x03070000
     // The only case we should go further and acquire the GIL: it is unlocked.
     if (PyGILState_Check())
       return;
@@ -190,7 +189,7 @@ struct InitializePythonRAII {
 
 // `PyEval_ThreadsInitialized` was deprecated in Python 3.9 and removed in
 // Python 3.13. It has been returning `true` always since Python 3.7.
-#if (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 9) || (PY_MAJOR_VERSION < 3)
+#if PY_VERSION_HEX < 0x03090000
     if (PyEval_ThreadsInitialized()) {
 #else
     if (true) {
@@ -204,7 +203,7 @@ struct InitializePythonRAII {
 
 // `PyEval_InitThreads` was deprecated in Python 3.9 and removed in
 // Python 3.13.
-#if (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 9) || (PY_MAJOR_VERSION < 3)
+#if PY_VERSION_HEX < 0x03090000
       return;
     }
 
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/lldb-python.h b/lldb/source/Plugins/ScriptInterpreter/Python/lldb-python.h
index 378b9fa2a59865..2d9281f368a336 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/lldb-python.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/lldb-python.h
@@ -47,6 +47,10 @@ static llvm::Expected<bool> *g_fcxx_modules_workaround [[maybe_unused]];
 
 // Include python for non windows machines
 #include <Python.h>
+
+// Provide a meaningful diagnostic error if someone tries to compile this file
+// with a version of Python we don't support.
+static_assert(PY_VERSION_HEX >= 0x03000000, "LLDB requires Python 3.0");
 #endif
 
 #endif // LLDB_PLUGINS_SCRIPTINTERPRETER_PYTHON_LLDB_PYTHON_H
diff --git a/lldb/unittests/ScriptInterpreter/Python/PythonDataObjectsTests.cpp b/lldb/unittests/ScriptInterpreter/Python/PythonDataObjectsTests.cpp
index b90fbb7830995f..365ebc8e52c246 100644
--- a/lldb/unittests/ScriptInterpreter/Python/PythonDataObjectsTests.cpp
+++ b/lldb/unittests/ScriptInterpreter/Python/PythonDataObjectsTests.cpp
@@ -760,7 +760,7 @@ class NewStyle(object):
     EXPECT_EQ(arginfo.get().max_positional_args, 3u);
   }
 
-#if PY_MAJOR_VERSION >= 3 && PY_MINOR_VERSION >= 3
+#if PY_VERSION_HEX >= 0x03030000
 
   // the old implementation of GetArgInfo just doesn't work on builtins.
 

[DavidSpickett]

Pavel's request so he can approve but looks fine to me. The static assert is a nice addition.

I see the set home change had to be reverted but I assume you're sorting all that out yourself.

[DavidSpickett]

"at least Python 3.0"

[labath]

I wish python exposed the linux-style macro to construct an arbitrary version number (#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + ((c) > 255 ? 255 : (c)))) as figuring out what version does 0x030d0000 refer to is not completely trivial. Though I still think that's better than (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 13) || (PY_MAJOR_VERSION > 3)

If python starts going over 3.16, we may want to create our own macro like that.

The static assert is a nice touch.