• Russ Cox's avatar
    cmd/gc: fix &result escaping into result · f20e4d5e
    Russ Cox authored
    There is a hierarchy of location defined by loop depth:
    
            -1 = the heap
            0 = function results
            1 = local variables (and parameters)
            2 = local variable declared inside a loop
            3 = local variable declared inside a loop inside a loop
            etc
    
    In general if an address from loopdepth n is assigned to
    something in loop depth m < n, that indicates an extended
    lifetime of some form that requires a heap allocation.
    
    Function results can be local variables too, though, and so
    they don't actually fit into the hierarchy very well.
    Treat the address of a function result as level 1 so that
    if it is written back into a result, the address is treated
    as escaping.
    
    Fixes #8185.
    
    LGTM=iant
    R=iant
    CC=golang-codereviews
    https://golang.org/cl/108870044
    f20e4d5e
esc.c 32.8 KB