Re: STM32F4 GNAT Run Time System - roadmap

[jan.de.kruyf@gmail.com]

On Tuesday, June 9, 2015 at 2:02:25 PM UTC+2, Simon Wright wrote:
> Looking for some input on priorities for work.
> 
> * Standard library packages.
> * Other MCUs.
> * Finalization.
> * ?
> 
> Standard library packages
> -------------------------
> 
> An obvious omission is the rest of the Ada.Containers.Bounded* packages:
>   Doubly_Linked_Lists
>   Ordered_Maps
>   Hashed_Sets
>   Ordered_Sets
>   Multiway_Trees
>   Synchronized_Queues
>   Priority_Queues
> 
> Any other nice-to-haves? (I haven't looked at Annex G, might be
> problematic!)
> 
> Other MCUs
> ----------
> 
> STM have just released a significant number of affordable Nucleo
> development kits. The NUCLEO-F091RC has 48 MHz Cortex-M0 core, 256-KB
> Flash, 32-KB SRAM, which would just-about take my current testbed
> program; for the princely sum of UKP7.94 + p&p, 88 in stock in UK for
> next day delivery from Farnell[0].
> 
> The problem with this is that different MCUs require different compiler
> options, and building GCC for ARM with multilibs is only supported in
> the ARM fork at [1]; so far there are only GCC 4.9-based releases. GCC
> 4.9 is a perfectly competent compiler, of course.
> 
> Finalization
> ------------
> 
> It would be very nice to be able to use the generalized container
> iterators of Ada 2012 (generalized array iterators are already OK).
> 
> They require finalization: I've implemented finalization and generalized
> iteration over Bounded_Vectors in the 'finalization' branch at [2].
> 
> Unfortunately, adding finalization to a restricted runtime triggers bugs
> in GCC.
> 
> I've raised two GCC PRs; "gnatbind generates invalid code when
> finalization is enabled in restricted runtime"[3], and "Front-end error
> if exception propagation disabled"[4].
> 
> =====================================================================
> [0] http://uk.farnell.com/stm32-mcu-nucleo-board-flexible-prototyping
> [1] https://launchpad.net/gcc-arm-embedded
> [2]
> https://sourceforge.net/p/stm32f4-gnat-rts/code/ci/finalization/tree/
> [3] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66205
> [4] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66242

And here is a b-demo.adb for use with a standard library

--------------------

pragma Ada_95;
pragma Source_File_Name (ada_main, Spec_File_Name => "b~demo.ads");
pragma Source_File_Name (ada_main, Body_File_Name => "b~demo.adb");

package body ada_main is
   pragma Warnings (Off);

   E04 : Short_Integer; pragma Import (Ada, E04, "last_chance_handler_E");
   E06 : Short_Integer; pragma Import (Ada, E06, "linux_kernel_E");
   E20 : Short_Integer; pragma Import (Ada, E20, "niniel_E");
   E27 : Short_Integer; pragma Import (Ada, E27, "niniel__ioctl_E");
   E31 : Short_Integer; pragma Import (Ada, E31, "secondary_stack_E");

   Local_Priority_Specific_Dispatching : constant String := "";
   Local_Interrupt_States : constant String := "";

   Is_Elaborated : Boolean := False;

   type No_Param_Proc is access procedure;

   procedure adainit is
      Main_Priority : Integer;
      pragma Import (C, Main_Priority, "__gl_main_priority");
      Time_Slice_Value : Integer;
      pragma Import (C, Time_Slice_Value, "__gl_time_slice_val");
      WC_Encoding : Character;
      pragma Import (C, WC_Encoding, "__gl_wc_encoding");
      Locking_Policy : Character;
      pragma Import (C, Locking_Policy, "__gl_locking_policy");
      Queuing_Policy : Character;
      pragma Import (C, Queuing_Policy, "__gl_queuing_policy");
      Task_Dispatching_Policy : Character;
      pragma Import (C, Task_Dispatching_Policy, "__gl_task_dispatching_policy");
      Priority_Specific_Dispatching : System.Address;
      pragma Import (C, Priority_Specific_Dispatching, "__gl_priority_specific_dispatching");
      Num_Specific_Dispatching : Integer;
      pragma Import (C, Num_Specific_Dispatching, "__gl_num_specific_dispatching");
      Main_CPU : Integer;
      pragma Import (C, Main_CPU, "__gl_main_cpu");
      Interrupt_States : System.Address;
      pragma Import (C, Interrupt_States, "__gl_interrupt_states");
      Num_Interrupt_States : Integer;
      pragma Import (C, Num_Interrupt_States, "__gl_num_interrupt_states");
      Unreserve_All_Interrupts : Integer;
      pragma Import (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts");
      Exception_Tracebacks : Integer;
      pragma Import (C, Exception_Tracebacks, "__gl_exception_tracebacks");
      Detect_Blocking : Integer;
      pragma Import (C, Detect_Blocking, "__gl_detect_blocking");
      Default_Stack_Size : Integer;
      pragma Import (C, Default_Stack_Size, "__gl_default_stack_size");
      Leap_Seconds_Support : Integer;
      pragma Import (C, Leap_Seconds_Support, "__gl_leap_seconds_support");

      procedure Install_Handler;
      pragma Import (C, Install_Handler, "__gnat_install_handler");

      Handler_Installed : Integer;
      pragma Import (C, Handler_Installed, "__gnat_handler_installed");

      Finalize_Library_Objects : No_Param_Proc;
      pragma Import (C, Finalize_Library_Objects, "__gnat_finalize_library_objects");
   begin
      if Is_Elaborated then
         return;
      end if;
      Is_Elaborated := True;
      Main_Priority := -1;
      Time_Slice_Value := -1;
      WC_Encoding := 'b';
      Locking_Policy := ' ';
      Queuing_Policy := ' ';
      Task_Dispatching_Policy := ' ';
      Priority_Specific_Dispatching :=
        Local_Priority_Specific_Dispatching'Address;
      Num_Specific_Dispatching := 0;
      Main_CPU := -1;
      Interrupt_States := Local_Interrupt_States'Address;
      Num_Interrupt_States := 0;
      Unreserve_All_Interrupts := 0;
      Exception_Tracebacks := 1;
      Detect_Blocking := 0;
      Default_Stack_Size := -1;
      Leap_Seconds_Support := 0;

      if Handler_Installed = 0 then
         Install_Handler;
      end if;

      E06 := E06 + 1;
      E04 := E04 + 1;
      if E20 = 0 then
         Niniel'Elab_Body;
      end if;
      E20 := E20 + 1;
      if E27 = 0 then
         Niniel.Ioctl'Elab_Body;
      end if;
      E27 := E27 + 1;
      E31 := E31 + 1;
   end adainit;

end ada_main;

-------------------------------------

now al of a sudden there is a mass of symbols imported from somewhere.
I am sure some diligent use of grep and/or nm will find them back in some library.

These files are generated by binding with gnat (gcc 4.7.4) by the way, on a 64 bit linux system.

j.