[Bug middle-end/21103] New: segfault with -fdump-tree-generic

[fxcoudert at gcc dot gnu dot org]

Compiling following code:
      program chk
      character*8 a
      a = 'a string'
      end

with gfortran and the -fdump-tree-generic induces a segfault:

Program received signal SIGSEGV, Segmentation fault.
0x0857af51 in dump_function_to_file (fn=0xb7ad6438, file=0x87ce8b8, flags=512)
    at ../../../gcc/gcc/tree-cfg.c:5186
5186      if (basic_block_info)
(gdb) where
#0  0x0857af51 in dump_function_to_file (fn=0xb7ad6438, file=0x87ce8b8, 
    flags=512) at ../../../gcc/gcc/tree-cfg.c:5186
#1  0x084e223f in dump_function (phase=TDI_generic, fn=0xb7ad6438)
    at ../../../gcc/gcc/tree-dump.c:1020
#2  0x080b420a in gfc_gimplify_function (fndecl=0xb7ad6438)
    at ../../../gcc/gcc/fortran/trans-decl.c:1289

This is specific to the generic tree dump, and is solved by the following change
in gcc/tree-cfg.c, line 5186:

-  if (basic_block_info)
+  if (cfun && basic_block_info)
      /* Make a CFG based dump.  */
  else
      /* Make a tree based dump.  */

The segfault actually occurs because basic_block_info is a macro for
cfun->cfg->x_basic_block_info and cfun is NULL in that case.

I don't know if this patch isn't hiding something deeper, so I report everything
I found here (which is not much, sorry, but that part of the compiler is too
deep for me!).

PS: I'm not sure the component should be middle-end, please change it if need be.

-- 
           Summary: segfault with -fdump-tree-generic
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: fxcoudert at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21103