GHDL 0.29 for Windows hangs if the number of statements in a process is even

Question

I'm using GHDL 0.29 for Windows.

The following program prints "Hello world!"

 use std.textio.all;

 entity hello_world is
 end hello_world;

 architecture behaviour of hello_world is
 begin
    process
       variable l : line;
    begin
       write (l, String'("Hello world!"));
       writeline (output, l);
       wait;
    end process;
 end behaviour;

The following program hangs and doesn't print anything.

 use std.textio.all;

 entity hello_world is
 end hello_world;

 architecture behaviour of hello_world is
 begin
    process
       variable l : line;
    begin
       assert false report "Foo" severity note;
       write (l, String'("Hello world!"));
       writeline (output, l);
       wait;
    end process;
 end behaviour;

The following program outputs the two assertions and then the "Hello world!" message.

 use std.textio.all;

 entity hello_world is
 end hello_world;

 architecture behaviour of hello_world is
 begin
    process
       variable l : line;
    begin
       assert false report "Foo" severity note;
       assert false report "bar" severity note;
       write (l, String'("Hello world!"));
       writeline (output, l);
       wait;
    end process;
 end behaviour;

I tried increasing the number of assertions and I discovered that when I have an odd number of assertions, the simulation hangs. It doesn't even matter where they are located. The following hangs:

   assert false report "Foo" severity note;
   assert false report "bar" severity note;
   assert false report "zoz" severity note;
   assert false report "lol" severity note;
   assert false report "mok" severity note;
   assert false report "antidisestablishmentarianism" severity note;
   write (l, String'("Hello world!"));
   writeline (output, l);
   wait;
   assert false report "asd" severity note;

The following prints everything up to the "antidisestablishmentarianism" assert:

   assert false report "Foo" severity note;
   assert false report "bar" severity note;
   assert false report "zoz" severity note;
   assert false report "lol" severity note;
   assert false report "mok" severity note;
   assert false report "antidisestablishmentarianism" severity note;
   write (l, String'("Hello world!"));
   writeline (output, l);
   wait;
   assert false report "asd" severity note;
   assert false report "gneeek" severity note;

Edit

The problem is more general, and seems to be related with the number of statements within a process being odd or even. The following prints "Hello world!Hello moon!" repeatedly:

 --  Hello world program.
 use std.textio.all; --  Imports the standard textio package.

 --  Defines a design entity, without any ports.
 entity hello_world is
 end hello_world;

 architecture behaviour of hello_world is
 begin
    process
       variable l : line;
    begin
       write (l, String'("Hello world!"));
       write (l, String'("Hello moon!"));
       writeline (output, l);
    end process;
 end behaviour;

While the following doesn't print anything and hangs:

 --  Hello world program.
 use std.textio.all; --  Imports the standard textio package.

 --  Defines a design entity, without any ports.
 entity hello_world is
 end hello_world;

 architecture behaviour of hello_world is
 begin
    process
       variable l : line;
    begin
       write (l, String'("Hello world!"));
       writeline (output, l);
    end process;
 end behaviour;

Edit (this may save you some time)

The weird behavior described above doesn't occur under Linux. Clearly, one of the two versions of GHDL is seriously flawed, and I strongly suspect that it is the Windows one. I'll file a bug report. I'm still interested in why the behavior is different.

Edit (I also tried with version 0.25)

With version 0.25 for Windows I get this error:

C:\Users\AjejeBrazorf\Documents\Programming\GHDL\Example>ghdl -a 1.vhdl
1.vhdl:1:10: file textio.v93 has changed and must be reanalysed

The ghdl.exe is the one packaged with the GTKWave bundle (https://stackoverflow.com/a/16629872/415727).

Answer 1

I've seen similar problems with the Windows GHDL 0.29.x builds.

Your example runs OK using either GHDL 0.25 or a patched 0.29.1.

GHDL 0.25 Windows build

EDIT: note, the following bundled installer seems to have VHDL library timestamp issues

Handy bundle of GHDL 0.25 + GTK Wave, from here