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Branches: main Fix two compiler aborts in the structure sharing analysis. compiler/ctgc.selector.m: Fix a problem with widening structure sharing pairs in the presence of existential types. We'd try to reduce a term selector to a type selector of the type of the node selected by the term selector, but if that node would be existentially typed then the compiler would abort. To avoid that, we resort to reducing the selector to a type selector of the parent node's type instead. Make `type_of_node' and `select_subtype' into semidet predicates which fail if the selector would select an existentially typed node, rather than aborting. Add det versions of the original functions. Make `select_subtype' able to succeed on existentially typed functors if the selector doesn't actually select an existentally typed argument. compiler/structure_sharing.domain.m: Don't add a new sharing pair to a sharing set if the left and right hand sides of the sharing pair are the same after normalisation. This avoids a different abort if such a pair needs to be removed: it tries to remove both (LHS - RHS) and (RHS - LHS) but since the two sides are equal, only one copy of the pair would exist in the sharing set to be removed. tests/valid/Mercury.options: tests/valid/Mmakefile: tests/valid/sharing_exist.m: Add test case.
25 lines
577 B
Mathematica
25 lines
577 B
Mathematica
% Regression test. Structure sharing widening caused compiler aborts in the
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% presence of existential types.
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%
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% Uncaught Mercury exception:
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% Software Error: ctgc.selector.m: Unexpected: get_type_of_node: existential
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% type.
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:- module sharing_exist.
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:- interface.
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:- type quux
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---> some [T] quux(T, string).
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:- pred replace(quux::in, T::in, quux::out) is det.
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%-----------------------------------------------------------------------------%
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:- implementation.
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replace(Q0, X, Q) :-
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Q0 = quux(_, Y),
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Q = 'new quux'(X, Y).
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% vi:ft=mercury:ts=8:sts=4:sw=4:et
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