HANDLE_TH_ERRORS: Move exception translation out of line (pytorch#69974)

Summary:
I've noticed that the `HANDLE_TH_ERRORS` macros are actually very expensive in terms of compile time.  Moving the bulk of the catch statements out of line using a lippincott function significantly improves compile times and object file binary sizes. For just the generated autograd bindings, this halves serial build time from 8 minutes to 4 and binary size is more than halved for most files with the biggest difference being `python_variable_methods.cpp` which went from 126 MB to 43 MB.

Pull Request resolved: pytorch#69974

Reviewed By: mruberry

Differential Revision: D33160899

Pulled By: albanD

fbshipit-source-id: fc35fa86f69ffe5a0752557be30b438c8564e998

torch/csrc/Exceptions.cpp

@@ -139,6 +139,15 @@ static std::string formatMessage(const char *format, va_list fmt_args) {
   return std::string(error_buf);
 }
 
+void translate_exception_to_python(const std::exception_ptr &e_ptr) {
+  try {
+    TORCH_INTERNAL_ASSERT(e_ptr, "translate_exception_to_python "
+                          "called with invalid exception pointer");
+    std::rethrow_exception(e_ptr);
+  }
+  CATCH_ALL_ERRORS(return)
+}
+
 IndexError::IndexError(const char *format, ...) {
   va_list fmt_args;
   va_start(fmt_args, format);

torch/csrc/Exceptions.h

@@ -132,7 +132,10 @@ static inline void PyErr_SetString(PyObject* type, const std::string& message) {
   catch (torch::jit::JITException & e) {                                 \
     throw;                                                               \
   }                                                                      \
-  CATCH_ALL_ERRORS(throw py::error_already_set())
+  catch (const std::exception & e) {                                     \
+    torch::translate_exception_to_python(std::current_exception());      \
+    throw py::error_already_set();                                       \
+  }
 
 #define END_HANDLE_TH_ERRORS_RET(retval)                             \
     }                                                                \
@@ -141,7 +144,10 @@ static inline void PyErr_SetString(PyObject* type, const std::string& message) {
       throw;                                                         \
     }                                                                \
   }                                                                  \
-  CATCH_ALL_ERRORS(return retval)
+  catch (const std::exception & e) {                                 \
+    torch::translate_exception_to_python(std::current_exception());  \
+    return retval;                                                   \
+  }
 
 #define END_HANDLE_TH_ERRORS END_HANDLE_TH_ERRORS_RET(nullptr)
 
@@ -258,6 +264,9 @@ bool THPException_init(PyObject *module);
 
 namespace torch {
 
+// Set python current exception from a C++ exception
+TORCH_PYTHON_API void translate_exception_to_python(const std::exception_ptr &);
+
 TORCH_PYTHON_API std::string processErrorMsg(std::string str);
 
 TORCH_PYTHON_API bool get_cpp_stacktraces_enabled();