diff options
author | Corinna Vinschen <corinna@vinschen.de> | 2016-03-10 00:55:28 +0300 |
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committer | Corinna Vinschen <corinna@vinschen.de> | 2016-03-10 00:55:28 +0300 |
commit | 264b5e137e20d0a8062497f8555759eb8bf8cc02 (patch) | |
tree | 6df0a17dcb984af4cb0c59edecd9bcacc4e1a348 | |
parent | c09e96fda04989dcf0948e797deb8f096e12f2fa (diff) |
Move definition of wsadata into wsock_init
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>
-rw-r--r-- | winsup/cygwin/autoload.cc | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/winsup/cygwin/autoload.cc b/winsup/cygwin/autoload.cc index bc13e07df..422e2c984 100644 --- a/winsup/cygwin/autoload.cc +++ b/winsup/cygwin/autoload.cc @@ -480,7 +480,6 @@ std_dll_init () } /* Initialization function for winsock stuff. */ -WSADATA NO_COPY wsadata; #ifdef __x86_64__ /* See above comment preceeding std_dll_init. */ @@ -493,6 +492,10 @@ __attribute__ ((used, noinline)) static two_addr_t wsock_init () #endif { + /* CV 2016-03-09: Moved wsadata into wsock_init to workaround a problem + with the NO_COPY definition of wsadata and here starting with gcc-5.3.0. + See the git log for a description. */ + static WSADATA NO_COPY wsadata; static LONG NO_COPY here = -1L; #ifndef __x86_64__ struct func_info *func = (struct func_info *) __builtin_return_address (0); |