• Russ Cox's avatar
    change representation of interface values. · 2da5022b
    Russ Cox authored
    this is not a user-visible change.
    
    before, all interface values were
    
    	struct Itype {
    		Sigt *type;
    		Sigi *inter;
    		void *method[n];
    	}
    
    	struct Iface {
    		void *addr;
    		Itype *itype;
    	}
    
    the itype is basically a vtable, but it's unnecessary
    if the static type is interface{ }.
    for interface values with static type empty, the
    new representation is
    
    	struct Eface {
    		void *addr;
    		Sigt *type;
    	}
    
    this complicates the code somewhat, but
    it reduces the number of Itypes that
    have to be computed and cached,
    it opens up opportunities to avoid function
    calls in a few common cases,
    and it will make it possible to lay out
    interface{} values at compile time,
    which i think i'll need for the new reflection.
    
    R=ken
    OCL=28701
    CL=29121
    2da5022b
runtime.h 9.81 KB