QtWebKit for x64 from Qt 5.3.2 crashes in JavaScriptCore

When I run QtWebKit for x64 in a loop accessing a web page like www.google.com, at some point I get a crash in X86Assembler::setRel32. More exactly the assertion ASSERT(offset == static_cast<int32_t>(offset)) fails.

This is exactly the behavior from QTBUG-23871 which was reported for Qt Script module. It seems that the Qt Script uses an older version of JSC and it was patched, but I could not find a suitable patch for QtWebKit.

Is there any patch for this issue or could you provide one?

The QtWebKit build for x86 does not seem to be affected by this problem.

This issue is critical and is basically a regression from Qt 4.8 which makes the QtWebKit build for x64 very unreliable.