On Sun, Apr 24, 2016 at 03:50:41PM +0200, Timo Buhrmester wrote: > Dump of assembler code for function mcount: > 0x0805045f <+0>: push %ebp > 0x08050460 <+1>: push %edi > 0x08050461 <+2>: push %esi > 0x08050462 <+3>: push %ebx > 0x08050463 <+4>: sub $0x18,%esp > 0x08050466 <+7>: mov %eax,%ebp > 0x08050468 <+9>: mov %ecx,0x8(%esp) > 0x0805046c <+13>: mov %edx,%esi > => 0x0805046e <+15>: mov 0x4(%ebp),%ebx > 0x08050471 <+18>: mov 0x0(%ebp),%edi > 0x08050474 <+21>: mov 0x4(%edi),%edi > 0x08050477 <+24>: mov 0x80759e0,%ecx > 0x0805047d <+30>: test %ecx,%ecx > 0x0805047f <+32>: je 0x805049f <mcount+64> > 0x08050481 <+34>: mov 0x8074880,%edx > 0x08050487 <+40>: test %edx,%edx > 0x08050489 <+42>: je 0x805052f <mcount+208>
It appears that the mcount() entry point defined in sys/arch/i386/include/profile.h is flatly broken with the new gcc -- the marked instruction is from an __asm that assumes a frame pointer and there is no frame pointer. Judging by what that code appears to be doing (e.g. saving caller-save registers), writing it in C with __asm seems a mistake and bound to explode with every new compiler version... -- David A. Holland dholl...@netbsd.org
