[Bug regression/37629] New: auto-import of constant data results in a crash at runtime

[jkolb at wsi dot com]

Compiling ffmpeg (see
http://sourceforge.net/tracker2/?func=detail&aid=2118261&group_id=202880&atid=983354)
under mingw-w64 into a DLL results in a runtime crash involving two dlls.

in libavutil.dll:
const uint8_t ff_log2_tab[256];

in libavcodec.dll:
extern const uint8_t ff_log2_tab[256];
static inline int av_log2(unsigned int)
{
...
}

which uses the ff_log2_tab array.  The ff_log2_tab array is auto-imported from
libavutil into libavcodec.

When av_log2 is called the resulting program crashes.  The workaround is to
explicitly import ff_log2_tab into libavcodec via:

__declspec(dllimport) const uint8_t ff_log2_tab[256];

If this is done the crash goes away.

This worked fine in gcc 4.3.


-- 
           Summary: auto-import of constant data results in a crash at
                    runtime
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: regression
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jkolb at wsi dot com
 GCC build triplet: x86_64-mingw-32
  GCC host triplet: x86_64-mingw-32
GCC target triplet: x86_64-mingw-32


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37629