An issue arose when we were testing our marshaler on a 
microbenchmark. The problem happens when a function is 
called with constant (read-only) data.

Consider a function foo that processes a char * string
passed to it as argument. The formal parameter to foo is
not a constant. So foo looks like:

void foo(char *string) {
	Process string appropriately;
}

Now, suppose that foo is a function for which we've to
generate marshaling/unmarshaling code.  

stub_foo(char *string) {
	marshal 'string' into 'buf'
	call a wrapper to foo that will demarshal 'buf', and
	call foo on the 
}