mirror of
git://sourceware.org/git/newlib-cygwin.git
synced 2025-01-18 04:19:21 +08:00
264b5e137e
The problem this patch fixes showed up after updating to gcc-5.3.0. The
cuplrit is a change in gcc when emitting section attributes. It only
shows up when building without optimization. Effect in Cygwin: ws2_32
functions failed to load.
In the original code the definition of "NO_COPY wsadata" was preceeding
an __asm__ block (the definition of the _wsock_init wrapper), while the
definition of "NO_COPY here" immediately follows the same assembler
block. When gcc-5.3.0 emits assembler code for the wsadata definition,
it emits the .data_cygwin_nocopy section attribute.
Next it emits the assembler output for the __asm_ block, entirely ignoring
its content. The __asm__ block adds a .text section definition.
Eventually gcc emits assembler code for the here definition. However,
apparently gcc still "knows" that it just emitted the .data_cygwin_nocopy
section attribute and so doesn't redefine it. Remember the __asm__? It
changed the section to .text.
So with gcc-4.9.3 we got:
.section .data_cygwin_nocopy,"w"
wsadata:
__asm__ block:
.text
.section .data_cygwin_nocopy,"w"
here:
With gcc 5.3.0 we now get:
.section .data_cygwin_nocopy,"w"
wsadata:
__asm__ block:
.text
here:
So "here" is now in the .text segment which is read-only. Hilarity ensues.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cygwin documentation is available on the net at http://cygwin.com You might especially be interested in http://cygwin.com/faq/faq.programming.html#faq.programming.building-cygwin