It's not necessarily accessible in a useful form for use by demand loaded modules; this is a common issue, leading to things like Apache and Perl moving most of their implementation into shared objects specifically so this kind of sharing will work. Additionally, since the demand loaded environment is a separate evaluation environment, all data will necessarily be duplicated (in theory sharing of initialized data with copy on write is possible, but in practice it's a lot of work and demand loading overhead for (for most C/C++ programs at least; ghc initialized data might differ) very little practical gain).
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