Bug#783293: browsers using webkit crash with 'illegal instruction' on i586

[Mark Hindley]

Hi,

I have been bitten by this too: all of my webkit browsers crash with 
SIGILL since upgrading to Jessie on non SSE hardware.

This patch at least fixes the environment variable so that 
JavaScriptCoreUseJIT=0 is honoured as a work-araound.

Mark


--- /tmp/VM.cpp	2015-05-18 12:04:42.183140915 +0100
+++ /tmp/VM-edited.cpp	2015-05-18 12:16:41.478098153 +0100
@@ -135,6 +135,11 @@
     }
 
 #if USE(CF)
+#if OS(UNIX)
+    char* canUseJITString = getenv("JavaScriptCoreUseJIT");
+    if (canUseJITString)
+      return !canUseJITString || atoi(canUseJITString);
+#endif // OS(UNIX)
 #if COMPILER(GCC) && !COMPILER(CLANG)
     // FIXME: remove this once the EWS have been upgraded to LLVM.
     // Work around a bug of GCC with strict-aliasing.
@@ -146,11 +151,6 @@
     RetainPtr<CFTypeRef> canUseJIT = adoptCF(CFPreferencesCopyAppValue(canUseJITKey, kCFPreferencesCurrentApplication));
     if (canUseJIT)
         return kCFBooleanTrue == canUseJIT.get();
-#endif
-
-#if USE(CF) || OS(UNIX)
-    char* canUseJITString = getenv("JavaScriptCoreUseJIT");
-    return !canUseJITString || atoi(canUseJITString);
 #else
     return true;
 #endif