readelf bug exposed with change from 2003-12-29

[Hans-Peter Nilsson <hans-peter dot nilsson at axis dot com>]

Hi.  Since this change:

2003-12-29  Nick Clifton  <nickc@redhat.com>

	* readelf.c (debug_line_pointer_size): Replace with an array
        called 'debug_line_pointer_sizes'.
        (num_debug_line_pointer_sizes): New variable.
        (display_debug_lines): Extract pointer size from the
        debug_line_pointer_sizes array.
        (display_debug_loc): Likewise.
        (prescan_debug_info): Fill in the debug_line_pointer_sizes
        array.

I'm getting these errors:

Running /home/hp/binutils/cvs_latest/src/gas/testsuite/gas/cris/cris.exp ...
FAIL: gas/cris/rd-dw2-1
FAIL: gas/cris/rd-dw2-10
FAIL: gas/cris/rd-dw2-11
FAIL: gas/cris/rd-dw2-12
FAIL: gas/cris/rd-dw2-13
FAIL: gas/cris/rd-dw2-14
FAIL: gas/cris/rd-dw2-15
FAIL: gas/cris/rd-dw2-2
FAIL: gas/cris/rd-dw2-3
FAIL: gas/cris/rd-dw2-4
FAIL: gas/cris/rd-dw2-5
FAIL: gas/cris/rd-dw2-6
FAIL: gas/cris/rd-dw2-7
FAIL: gas/cris/rd-dw2-8
FAIL: gas/cris/rd-dw2-9

In gas.log they all look like:

../as-new  --em=criself --gdwarf2 -o dump.o /home/hp/binutils/cvs_latest/src/gas/testsuite/gas/cris/addi.s
/dsk/c0t3s2/hptmp2/autobuildbinu/binu/gas/testsuite/../../binutils/readelf  -wl dump.o > dump.out
readelf: Error: Not enough comp units for .debug_lines section
FAIL: gas/cris/rd-dw2-1

Looking at readelf.c code nearby the change, sections are
iterated in file order and a function display_debug_section is
called, iterating on an array called debug_displays, calling
some functions for certain section names.  The function
prescan_debug_info is called for ".debug_info".  That function
needs to be called to initialize pointer sizes before users of
that information, like display_debug_lines (for ".debug_lines")
are called, else the latter functions hork as seen above.

The current scheme seems to rely on the section ".debug_info"
being located before ".debug_lines" in a file, which would be
pure coincidence, breaking here when encountering GAS-generated
debug info.  It worked before the patch above which seems to
have removed a fallback to assume pointer size = 4.

Unfortunately I see no small and obvious fix.  Reinstating the
fallback would just be a hack.

brgds, H-P