[Tinycc-devel] bug in tcc-0.9.20

[David Hovemeyer]

First of all, Tiny CC is a great project, so many kudos to Fabrice
and the developers.

I'm trying to compile a small operating system project (which I
developed using gcc) with Tiny CC version 0.9.20, and I think I've run
into a bug.  (The same bug also appears to be in the latest CVS sources
at Savannah.)  A complete test case with a Makefile is at

  http://www.cs.umd.edu/~daveho/tccbug.tar.gz

Here a the code excerpt:

  /**
   * Global table of system call handler functions.
   */
  const Syscall g_syscallTable[] = {
      Sys_Null,
      Sys_Exit,
      Sys_PrintString,
      Sys_GetKey,
      Sys_SetAttr,
      Sys_Spawn,
      Sys_Wait,
  };
  
  /**
   * Number of system calls implemented.
   */
  const int g_numSyscalls = sizeof(g_syscallTable) / sizeof(Syscall);

"Syscall" is a typedef for function pointer.  Sys_Null, Sys_Exit, etc.
are all static functions defined earlier in the file.  When I compile
this code, I get the error 

  syscall.c:211: sizeof applied to an incomplete type

Line 211 is where g_numSyscalls is defined.

I poked around in tcc.c a bit, and looked at the type_size() function.
In particular, I put a printf() in the part of the code that appears
to determine the size of arrays, as follows (line 5549 of tcc.c):

    } else if (bt == VT_PTR) {
        if (type->t & VT_ARRAY) {
            s = type->ref;
            printf("s->c == %d\n", s->c);
            return type_size(&s->type, a) * s->c;

This statement produces the output

  s->c == -1

just before error is reported, which makes me think that tcc is
confused somehow about the number of elements in the array.
Unfortunately, I wasn't able to come up with a simple test case.
The tar file I mentioned above simply contains all of the source
and header files required to compile the file (syscall.c).

-Dave