[lldb] Remove 'extern "C"' from the lldb-swig-python interface

The LLDBSWIGPython functions had (at least) two problems:
- There wasn't a single source of truth (a header file) for the
  prototypes of these functions. This meant that subtle differences
  in copies of function declarations could go by undetected. And
  not-so-subtle differences would result in strange runtime failures.
- All of the declarations had to have an extern "C" interface, because
  the function definitions were being placed inside and extert "C" block
  generated by swig.

This patch fixes both problems by moving the function definitions to the
%header block of the swig files. This block is not surrounded by extern
"C", and seems more appropriate anyway, as swig docs say it is meant for
"user-defined support code" (whereas the previous %wrapper code was for
automatically-generated wrappers).

It also puts the declarations into the SWIGPythonBridge header file
(which seems to have been created for this purpose), and ensures it is
included by all code wishing to define or use these functions. This
means that any differences in the declaration become a compiler error
instead of a runtime failure.

Differential Revision: https://reviews.llvm.org/D114369

1 files changed, 15 insertions, 161 deletions

diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
index e8b1ad7..5f282d7 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
@@ -70,153 +70,6 @@ extern "C" void init_lldb(void);
 #define LLDBSwigPyInit init_lldb
 #endif
 
-// These prototypes are the Pythonic implementations of the required callbacks.
-// Although these are scripting-language specific, their definition depends on
-// the public API.
-
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
-
-// Disable warning C4190: 'LLDBSwigPythonBreakpointCallbackFunction' has
-// C-linkage specified, but returns UDT 'llvm::Expected<bool>' which is
-// incompatible with C
-#if _MSC_VER
-#pragma warning (push)
-#pragma warning (disable : 4190)
-#endif
-
-extern "C" llvm::Expected<bool> LLDBSwigPythonBreakpointCallbackFunction(
-    const char *python_function_name, const char *session_dictionary_name,
-    const lldb::StackFrameSP &sb_frame,
-    const lldb::BreakpointLocationSP &sb_bp_loc, StructuredDataImpl *args_impl);
-
-#if _MSC_VER
-#pragma warning (pop)
-#endif
-
-#pragma clang diagnostic pop
-
-extern "C" bool LLDBSwigPythonWatchpointCallbackFunction(
-    const char *python_function_name, const char *session_dictionary_name,
-    const lldb::StackFrameSP &sb_frame, const lldb::WatchpointSP &sb_wp);
-
-extern "C" bool LLDBSwigPythonCallTypeScript(
-    const char *python_function_name, void *session_dictionary,
-    const lldb::ValueObjectSP &valobj_sp, void **pyfunct_wrapper,
-    const lldb::TypeSummaryOptionsSP &options_sp, std::string &retval);
-
-extern "C" void *
-LLDBSwigPythonCreateSyntheticProvider(const char *python_class_name,
-                                      const char *session_dictionary_name,
-                                      const lldb::ValueObjectSP &valobj_sp);
-
-extern "C" void *
-LLDBSwigPythonCreateCommandObject(const char *python_class_name,
-                                  const char *session_dictionary_name,
-                                  const lldb::DebuggerSP debugger_sp);
-
-extern "C" void *LLDBSwigPythonCreateScriptedThreadPlan(
-    const char *python_class_name, const char *session_dictionary_name,
-    StructuredDataImpl *args_data,
-    std::string &error_string,
-    const lldb::ThreadPlanSP &thread_plan_sp);
-
-extern "C" bool LLDBSWIGPythonCallThreadPlan(void *implementor,
-                                             const char *method_name,
-                                             Event *event_sp, bool &got_error);
-
-extern "C" void *LLDBSwigPythonCreateScriptedBreakpointResolver(
-    const char *python_class_name, const char *session_dictionary_name,
-    lldb_private::StructuredDataImpl *args, const lldb::BreakpointSP &bkpt_sp);
-
-extern "C" unsigned int
-LLDBSwigPythonCallBreakpointResolver(void *implementor, const char *method_name,
-                                     lldb_private::SymbolContext *sym_ctx);
-
-extern "C" void *LLDBSwigPythonCreateScriptedStopHook(
-    TargetSP target_sp, const char *python_class_name,
-    const char *session_dictionary_name, lldb_private::StructuredDataImpl *args,
-    lldb_private::Status &error);
-
-extern "C" bool
-LLDBSwigPythonStopHookCallHandleStop(void *implementor,
-                                     lldb::ExecutionContextRefSP exc_ctx,
-                                     lldb::StreamSP stream);
-
-extern "C" size_t LLDBSwigPython_CalculateNumChildren(void *implementor,
-                                                      uint32_t max);
-
-extern "C" void *LLDBSwigPython_GetChildAtIndex(void *implementor,
-                                                uint32_t idx);
-
-extern "C" int LLDBSwigPython_GetIndexOfChildWithName(void *implementor,
-                                                      const char *child_name);
-
-extern lldb::ValueObjectSP
-LLDBSWIGPython_GetValueObjectSPFromSBValue(void *data);
-
-extern "C" bool LLDBSwigPython_UpdateSynthProviderInstance(void *implementor);
-
-extern "C" bool
-LLDBSwigPython_MightHaveChildrenSynthProviderInstance(void *implementor);
-
-extern "C" void *
-LLDBSwigPython_GetValueSynthProviderInstance(void *implementor);
-
-extern "C" bool
-LLDBSwigPythonCallCommand(const char *python_function_name,
-                          const char *session_dictionary_name,
-                          lldb::DebuggerSP &debugger, const char *args,
-                          lldb_private::CommandReturnObject &cmd_retobj,
-                          lldb::ExecutionContextRefSP exe_ctx_ref_sp);
-
-extern "C" bool
-LLDBSwigPythonCallCommandObject(void *implementor, lldb::DebuggerSP &debugger,
-                                const char *args,
-                                lldb_private::CommandReturnObject &cmd_retobj,
-                                lldb::ExecutionContextRefSP exe_ctx_ref_sp);
-
-extern "C" bool
-LLDBSwigPythonCallModuleInit(const char *python_module_name,
-                             const char *session_dictionary_name,
-                             lldb::DebuggerSP &debugger);
-
-extern "C" void *
-LLDBSWIGPythonCreateOSPlugin(const char *python_class_name,
-                             const char *session_dictionary_name,
-                             const lldb::ProcessSP &process_sp);
-
-extern "C" void *
-LLDBSWIGPython_CreateFrameRecognizer(const char *python_class_name,
-                                     const char *session_dictionary_name);
-
-extern "C" void *
-LLDBSwigPython_GetRecognizedArguments(void *implementor,
-                                      const lldb::StackFrameSP &frame_sp);
-
-extern "C" bool LLDBSWIGPythonRunScriptKeywordProcess(
-    const char *python_function_name, const char *session_dictionary_name,
-    const lldb::ProcessSP &process, std::string &output);
-
-extern "C" bool LLDBSWIGPythonRunScriptKeywordThread(
-    const char *python_function_name, const char *session_dictionary_name,
-    lldb::ThreadSP &thread, std::string &output);
-
-extern "C" bool LLDBSWIGPythonRunScriptKeywordTarget(
-    const char *python_function_name, const char *session_dictionary_name,
-    const lldb::TargetSP &target, std::string &output);
-
-extern "C" bool LLDBSWIGPythonRunScriptKeywordFrame(
-    const char *python_function_name, const char *session_dictionary_name,
-    lldb::StackFrameSP &frame, std::string &output);
-
-extern "C" bool LLDBSWIGPythonRunScriptKeywordValue(
-    const char *python_function_name, const char *session_dictionary_name,
-    const lldb::ValueObjectSP &value, std::string &output);
-
-extern "C" void *
-LLDBSWIGPython_GetDynamicSetting(void *module, const char *setting,
-                                 const lldb::TargetSP &target_sp);
 
 static ScriptInterpreterPythonImpl *GetPythonInterpreter(Debugger &debugger) {
   ScriptInterpreter *script_interpreter =
@@ -1591,9 +1444,9 @@ lldb::ValueObjectListSP ScriptInterpreterPythonImpl::GetRecognizedArguments(
   if (!implementor.IsAllocated())
     return ValueObjectListSP();
 
-  PythonObject py_return(PyRefType::Owned,
-                         (PyObject *)LLDBSwigPython_GetRecognizedArguments(
-                             implementor.get(), frame_sp));
+  PythonObject py_return(
+      PyRefType::Owned,
+      LLDBSwigPython_GetRecognizedArguments(implementor.get(), frame_sp));
 
   // if it fails, print the error but otherwise go on
   if (PyErr_Occurred()) {
@@ -2423,7 +2276,7 @@ size_t ScriptInterpreterPythonImpl::CalculateNumChildren(
   StructuredData::Generic *generic = implementor_sp->GetAsGeneric();
   if (!generic)
     return 0;
-  void *implementor = generic->GetValue();
+  auto *implementor = static_cast<PyObject *>(generic->GetValue());
   if (!implementor)
     return 0;
 
@@ -2446,7 +2299,7 @@ lldb::ValueObjectSP ScriptInterpreterPythonImpl::GetChildAtIndex(
   StructuredData::Generic *generic = implementor_sp->GetAsGeneric();
   if (!generic)
     return lldb::ValueObjectSP();
-  void *implementor = generic->GetValue();
+  auto *implementor = static_cast<PyObject *>(generic->GetValue());
   if (!implementor)
     return lldb::ValueObjectSP();
 
@@ -2454,7 +2307,7 @@ lldb::ValueObjectSP ScriptInterpreterPythonImpl::GetChildAtIndex(
   {
     Locker py_lock(this,
                    Locker::AcquireLock | Locker::InitSession | Locker::NoSTDIN);
-    void *child_ptr = LLDBSwigPython_GetChildAtIndex(implementor, idx);
+    PyObject *child_ptr = LLDBSwigPython_GetChildAtIndex(implementor, idx);
     if (child_ptr != nullptr && child_ptr != Py_None) {
       lldb::SBValue *sb_value_ptr =
           (lldb::SBValue *)LLDBSWIGPython_CastPyObjectToSBValue(child_ptr);
@@ -2478,7 +2331,7 @@ int ScriptInterpreterPythonImpl::GetIndexOfChildWithName(
   StructuredData::Generic *generic = implementor_sp->GetAsGeneric();
   if (!generic)
     return UINT32_MAX;
-  void *implementor = generic->GetValue();
+  auto *implementor = static_cast<PyObject *>(generic->GetValue());
   if (!implementor)
     return UINT32_MAX;
 
@@ -2503,7 +2356,7 @@ bool ScriptInterpreterPythonImpl::UpdateSynthProviderInstance(
   StructuredData::Generic *generic = implementor_sp->GetAsGeneric();
   if (!generic)
     return ret_val;
-  void *implementor = generic->GetValue();
+  auto *implementor = static_cast<PyObject *>(generic->GetValue());
   if (!implementor)
     return ret_val;
 
@@ -2526,7 +2379,7 @@ bool ScriptInterpreterPythonImpl::MightHaveChildrenSynthProviderInstance(
   StructuredData::Generic *generic = implementor_sp->GetAsGeneric();
   if (!generic)
     return ret_val;
-  void *implementor = generic->GetValue();
+  auto *implementor = static_cast<PyObject *>(generic->GetValue());
   if (!implementor)
     return ret_val;
 
@@ -2550,14 +2403,15 @@ lldb::ValueObjectSP ScriptInterpreterPythonImpl::GetSyntheticValue(
   StructuredData::Generic *generic = implementor_sp->GetAsGeneric();
   if (!generic)
     return ret_val;
-  void *implementor = generic->GetValue();
+  auto *implementor = static_cast<PyObject *>(generic->GetValue());
   if (!implementor)
     return ret_val;
 
   {
     Locker py_lock(this,
                    Locker::AcquireLock | Locker::InitSession | Locker::NoSTDIN);
-    void *child_ptr = LLDBSwigPython_GetValueSynthProviderInstance(implementor);
+    PyObject *child_ptr =
+        LLDBSwigPython_GetValueSynthProviderInstance(implementor);
     if (child_ptr != nullptr && child_ptr != Py_None) {
       lldb::SBValue *sb_value_ptr =
           (lldb::SBValue *)LLDBSWIGPython_CastPyObjectToSBValue(child_ptr);
@@ -3075,9 +2929,9 @@ bool ScriptInterpreterPythonImpl::RunScriptBasedCommand(
     SynchronicityHandler synch_handler(debugger_sp, synchronicity);
 
     std::string args_str = args.str();
-    ret_val = LLDBSwigPythonCallCommandObject(impl_obj_sp->GetValue(),
-                                              debugger_sp, args_str.c_str(),
-                                              cmd_retobj, exe_ctx_ref_sp);
+    ret_val = LLDBSwigPythonCallCommandObject(
+        static_cast<PyObject *>(impl_obj_sp->GetValue()), debugger_sp,
+        args_str.c_str(), cmd_retobj, exe_ctx_ref_sp);
   }
 
   if (!ret_val)