Here's the disassembly from a good build with vanilla gcc 4.8.4. It's basically identical, but it contains 3 extra instructions that are missing from the broken build.
0xf57fe991 <+1729>: mov 0xa0(%ebp),%edx 0xf57fe997 <+1735>: mov 0x84(%esp),%esi // %esi now points to |pn| 0xf57fe99e <+1742>: add $0x18,%edx 0xf57fe9a1 <+1745>: cmpl $0xfe,0x28(%esp) // Compare |hops| with 254 (FREE_LEVEL - 1) 0xf57fe9a9 <+1753>: mov %al,0x2(%esi) // Calls pn->SetOp(op) 0xf57fe9ac <+1756>: mov 0x34(%esp),%eax // %eax now contains |slot| 0xf57fe9b0 <+1760>: ja 0xf57fea10 <js::frontend::BytecodeEmitter::tryConvertFreeName(js::frontend::ParseNode*)+1856> // Jump if |hops| > 254 0xf57fe9b2 <+1762>: cmp $0xffffff,%eax // Compare |slot| with 0xffffff 0xf57fe9b7 <+1767>: ja 0xf57fe9f9 <js::frontend::BytecodeEmitter::tryConvertFreeName(js::frontend::ParseNode*)+1833> // Jump if |slot| > 0xffffff 0xf57fe9b9 <+1769>: mov 0x84(%esp),%esi // %esi now points to |pn| 0xf57fe9c0 <+1776>: shl $0x8,%eax // Left shift new |slot| value by 8-bits // These next 3 instructions are missing in the broken build 0xf57fe9c3 <+1779>: mov $0x1,%edi 0xf57fe9c8 <+1784>: movzbl 0x28(%esp),%edx // %edx now contains |hops| 0xf57fe9cd <+1789>: mov %dl,0x20(%esi) // Save |hops| in to |level_| in pn->pn_u.name.cookie 0xf57fe9d0 <+1792>: mov %eax,%edx // %edx now contains |slot| 0xf57fe9d2 <+1794>: movzbl 0x20(%esi),%eax // Load |level_| from pn->pn_u.name.cookie in to %eax 0xf57fe9d6 <+1798>: or %edx,%eax // %eax now contains the bitwise-OR of |level_| and new |slot| value 0xf57fe9d8 <+1800>: mov %eax,0x20(%esi) // Save the new values to |level_| and |slot_| in pn->pn_u.name.cookie -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1471949 Title: Firefox 39 crashes on startup or within a few seconds on Precise/x86 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1471949/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
