[SCM] libav/experimental: Remove uses of SIGILL for CPU extension detection, that method is not acceptable in a library. Should not change anything for PPC, the autodetection is currently pointless due to other code being compiled with -maltivec as well (and detection for OSX and AmigaOS remains in place). SPARC binaries built with VIS support can now only run on systems with VIS.

[siretart at users.alioth.debian.org]

The following commit has been merged in the experimental branch:
commit d9a5dab2da1220b5bec718d343ecc30e22084676
Author: Reimar Döffinger <Reimar.Doeffinger at gmx.de>
Date:   Tue Oct 2 18:18:35 2007 +0000

    Remove uses of SIGILL for CPU extension detection, that method is not acceptable
    in a library.
    Should not change anything for PPC, the autodetection is currently pointless due
    to other code being compiled with -maltivec as well (and detection for OSX and
    AmigaOS remains in place).
    SPARC binaries built with VIS support can now only run on systems with VIS.
    
    Originally committed as revision 10648 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/libavcodec/ppc/check_altivec.c b/libavcodec/ppc/check_altivec.c
index 72b4afe..b3778ca 100644
--- a/libavcodec/ppc/check_altivec.c
+++ b/libavcodec/ppc/check_altivec.c
@@ -28,23 +28,6 @@
 #include <exec/exec.h>
 #include <interfaces/exec.h>
 #include <proto/exec.h>
-#else
-#include <signal.h>
-#include <setjmp.h>
-
-static sigjmp_buf jmpbuf;
-static volatile sig_atomic_t canjump = 0;
-
-static void sigill_handler (int sig)
-{
-    if (!canjump) {
-        signal (sig, SIG_DFL);
-        raise (sig);
-    }
-
-    canjump = 0;
-    siglongjmp (jmpbuf, 1);
-}
 #endif /* __APPLE__ */
 
 /**
@@ -72,24 +55,9 @@ int has_altivec(void)
     if (err == 0) return (has_vu != 0);
     return 0;
 #else
-/* Do it the brute-force way, borrowed from the libmpeg2 library. */
-    {
-      signal (SIGILL, sigill_handler);
-      if (sigsetjmp (jmpbuf, 1)) {
-        signal (SIGILL, SIG_DFL);
-      } else {
-        canjump = 1;
-
-        asm volatile ("mtspr 256, %0\n\t"
-                      "vand %%v0, %%v0, %%v0"
-                      :
-                      : "r" (-1));
-
-        signal (SIGILL, SIG_DFL);
-        return 1;
-      }
-    }
-    return 0;
+    // since we were compiled for altivec, just assume we have it
+    // until someone comes up with a proper way (not involving signal hacks).
+    return 1;
 #endif /* __AMIGAOS4__ */
 }
 
diff --git a/libavcodec/sparc/dsputil_vis.c b/libavcodec/sparc/dsputil_vis.c
index 4367b72..374ec8d 100644
--- a/libavcodec/sparc/dsputil_vis.c
+++ b/libavcodec/sparc/dsputil_vis.c
@@ -26,8 +26,6 @@
 #include "config.h"
 
 #include <inttypes.h>
-#include <signal.h>
-#include <setjmp.h>
 
 #include "dsputil.h"
 
@@ -3987,56 +3985,13 @@ static void MC_avg_no_round_xy_8_vis (uint8_t * dest, const uint8_t * _ref,
 
 /* End of no rounding code */
 
-static sigjmp_buf jmpbuf;
-static volatile sig_atomic_t canjump = 0;
-
-static void sigill_handler (int sig)
-{
-    if (!canjump) {
-        signal (sig, SIG_DFL);
-        raise (sig);
-    }
-
-    canjump = 0;
-    siglongjmp (jmpbuf, 1);
-}
-
 #define ACCEL_SPARC_VIS 1
 #define ACCEL_SPARC_VIS2 2
 
 static int vis_level ()
 {
-    int accel = 0;
-
-    signal (SIGILL, sigill_handler);
-    if (sigsetjmp (jmpbuf, 1)) {
-        signal (SIGILL, SIG_DFL);
-        return accel;
-    }
-
-    canjump = 1;
-
-    /* pdist %f0, %f0, %f0 */
-    __asm__ __volatile__(".word\t0x81b007c0");
-
-    canjump = 0;
     accel |= ACCEL_SPARC_VIS;
-
-    if (sigsetjmp (jmpbuf, 1)) {
-        signal (SIGILL, SIG_DFL);
-        return accel;
-    }
-
-    canjump = 1;
-
-    /* edge8n %g0, %g0, %g0 */
-    __asm__ __volatile__(".word\t0x81b00020");
-
-    canjump = 0;
     accel |= ACCEL_SPARC_VIS2;
-
-    signal (SIGILL, SIG_DFL);
-
     return accel;
 }
 

-- 
Libav/FFmpeg packaging