experimental stack-based virtual machine The patch adds a stack-based bytecode virtual machine (VM) for executing Octave functions. The user command __enable_vm_eval__ may be used to enables the VM dynamically. The VM is a work in progress. It does not currently support all of the functionality of the existing interpreter that recursively walks the parse tree to evaluate code. * compile.cc, pt-bytecode-vm-internal.h, pt-bytecode-vm.cc, pt-bytecode-vm.h, pt-bytecode-walk.cc, pt-bytecode-walk.h, pt-bytecode.h, pt-vm-eval.cc: New files * libinterp/corefcn/module.mk, libinterp/parse-tree/module.mk: Update. * call-stack.h, call-stack.cc (call_stack::push): New overload to push a stack frame for a bytecode compiled function on the stack. (call_stack::set_active_bytecode_ip): New function. (call_stack::find_current_user_frame, call_stack::dbupdown, call_stack::backtrace_frames call_stack::backtrace_info, call_stack::backtrace): Handle bytecode compiled function frames. * stack-frame.h, stack-frame.cc (bytecode_fcn_stack_frame): New class. (get_auto_fcn_var) (stack_frame_walker::visit_bytecode_fcn_stack_frame): New pure virtual function. (symbol_cleaner::visit_bytecode_fcn_stack_frame): New function. (symbol_info_accumulator::visit_bytecode_fcn_stack_frame): New function. (stack_frame::create_bytecode): New function. (stack_frame::is_bytecode_fcn_frame, stack_frame::get_active_bytecode_call_arg_names, stack_frame::set_active_bytecode_ip, stak_frame::vm_unwinds, stack_frame::vm_dbg_check_scope, stack_frame::vm_clear_for_cache): New virtual functions. * ov.h (octave_value::vm_need_storable_call, octave_value::vm_need_dispatch_assign_rhs, octave_value::vm_need_dispatch_assign_lhs, * ov-base.h (octave_base_value::vm_need_storable_call, octave_base_value::vm_need_dispatch_assign_rhs, octave_base_value::vm_need_dispatch_assign_lhs, octave_base_value::vm_need_dispatch_push): New virtual functions. * ov-base-mat.h (octave_base_matrix<MT>::vm_need_storable_call): New function. * ov-base-scalar.h (octave_base_scalar<ST>::vm_need_dispatch_assign_rhs, octave_base_scalar<ST>::vm_need_dispatch_assign_lhs, octave_base_scalar<ST>::vm_need_dispatch_push): New functions. * ov-magic-int.h (octave_base_magic_int<T>::vm_need_storable_call): New function. * ov-null-mat.h (octave_null_matrix::vm_need_storable_call, octave_null_str::vm_need_storable_call, octave_null_sq_str::vm_need_storable_call): New functions. * ov-range.h (ov_range<T>::vm_need_storable_call): New function. ov.h (octave_value::vm_need_dispatch_push, octave_value::same_rep): New function. * ov-fcn.cc (octave_function::call): Attempt to byte compile user-defined functions. * ov-user-fcn.h, ov-user-fcn.cc (octave_user_function::call): Attempt to byte compile function. (octave_user_function::set_bytecode, octave_user_function::clear_bytecode, octave_user_function::is_compiled, octave_user_function::get_bytecode): New functions. (octave_user_function::m_compilation_failed): New public data member. octave_user_function::m_bytecode): New data member. * ov.h (class ov): Declare octave::vm and octave::bytecode_fcn_stack_frame as friend classes. * pt-eval.h, pt-eval.cc (tree_evaluator::set_active_bytecode_ip): New function. (tree_evaluator::push_stack_frame): New overload to push a stack frame for a bytecode compiled function on the stack. (tree_evaluator::execute_user_function): Handle byte-compiled functions.

--- a/libinterp/parse-tree/module.mk	Mon Jun 19 17:27:37 2023 -0400
+++ b/libinterp/parse-tree/module.mk	Mon Apr 24 20:34:39 2023 +0200
@@ -15,6 +15,10 @@
   %reldir%/pt-assign.h \
   %reldir%/pt-binop.h \
   %reldir%/pt-bp.h \
+  %reldir%/pt-bytecode.h \
+  %reldir%/pt-bytecode-walk.h \
+  %reldir%/pt-bytecode-vm.h \
+  %reldir%/pt-bytecode-vm-internal.h \
   %reldir%/pt-cbinop.h \
   %reldir%/pt-cell.h \
   %reldir%/pt-check.h \
@@ -64,6 +68,8 @@
   %reldir%/pt-assign.cc \
   %reldir%/pt-binop.cc \
   %reldir%/pt-bp.cc \
+  %reldir%/pt-bytecode-walk.cc \
+  %reldir%/pt-bytecode-vm.cc \
   %reldir%/pt-cbinop.cc \
   %reldir%/pt-cell.cc \
   %reldir%/pt-check.cc \
@@ -86,7 +92,6 @@
   %reldir%/pt-stmt.cc \
   %reldir%/pt-tm-const.cc \
   %reldir%/pt-unop.cc \
-  %reldir%/pt-vm-eval.cc \
   %reldir%/pt-walk.cc \
   %reldir%/pt.cc \
   %reldir%/token.cc