jumps to middle of x86 instructions ?

Andrew Haley aph@redhat.com
Fri Apr 4 12:01:00 GMT 2008


Mithun R N Iyer wrote:
> Hi All: I see these weird jmps to middle of
> instructions in a binary. 
>  
> This is on x86, ubuntu gcc version: 4.1.3 with -O2
> optimization.
> 
> Can someone please let me know why such jumps are
> generated ? I have seen such jmps in case of lock
> prefix instructions but do not see any such
> instructions here. 
> There is no assembly code added in the sources.
> 
> The code snippet looks like:
> 0x0006c007 <strrchr+103>:       add    %al,(%eax)
> 0x0006c009 <strrchr+105>:       add   
> %al,0xee8304ee(%ebx)

When you build strrchr, generate an assembly file by compiling with
-save-temps.  I think you will find this is not code, but data.

Andrew.



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