[ft-devel] uninitialized value in gray_set_cell

[Derek B. Noonburg]

I upgraded from FreeType 2.6.3 to FreeType 2.7, and running regressions
on Xpdf, with valgrind, turned up a large number of "Conditional jump or
move depends on uninitialised value(s)" warnings.

It's happening on around two thirds of my tests, and it's only happening
once or a few times per PDF file -- so it's not happening for every
font, and it's definitely not happening every time I render a character.

The valgrind reports look like this:

==10214== Conditional jump or move depends on uninitialised value(s)
==10214==    at 0x81BB5C8: gray_set_cell (ftgrays.c:587)
==10214==    by 0x81BC2D6: gray_move_to (ftgrays.c:1204)
==10214==    by 0x816EB3E: FT_Outline_Decompose (ftoutln.c:143)
==10214==    by 0x808E224: gray_convert_glyph_inner.constprop.2 (ftgrays.c:1742)
==10214==    by 0x808E2CF: gray_convert_glyph (ftgrays.c:1825)
==10214==    by 0x81BC4FB: gray_raster_render (ftgrays.c:1968)
==10214==    by 0x81BB0BC: ft_smooth_render_generic (ftsmooth.c:308)
==10214==    by 0x816E644: FT_Render_Glyph_Internal (ftobjs.c:4180)
==10214==    by 0x816E6CB: FT_Render_Glyph (ftobjs.c:4271)
(rest of the callstack is my code)

or this:

==10226== Conditional jump or move depends on uninitialised value(s)
==10226==    at 0x81BB5C8: gray_set_cell (ftgrays.c:587)
==10226==    by 0x81BB999: gray_render_line (ftgrays.c:765)
==10226==    by 0x81BC29A: gray_line_to (ftgrays.c:1216)
==10226==    by 0x816ECAB: FT_Outline_Decompose (ftoutln.c:165)
==10226==    by 0x808E224: gray_convert_glyph_inner.constprop.2 (ftgrays.c:1742)
==10226==    by 0x808E2CF: gray_convert_glyph (ftgrays.c:1825)
==10226==    by 0x81BC4FB: gray_raster_render (ftgrays.c:1968)
==10226==    by 0x81BB0BC: ft_smooth_render_generic (ftsmooth.c:308)
==10226==    by 0x816E644: FT_Render_Glyph_Internal (ftobjs.c:4180)
==10226==    by 0x816E6CB: FT_Render_Glyph (ftobjs.c:4271)

Line 587 is:

    if ( ex != ras.ex || ey != ras.ey )

I know that's not much to go on, but does anyone have any ideas?

Version 2.6.3 ran with zero valgrind warnings.  The only change on my
end was upgrading to 2.7.  The output looks good (better than 2.6.3)
-- I'm not seeing any visible problems.

If there's anything I can do to help debug this, let me know.

- Derek