Clean-up symex assignments #4735
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romainbrenguier
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kroening,
martin-cs,
peterschrammel,
pkesseli,
smowton and
tautschnig
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src/goto-symex/symex_assign.cpp
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| @@ -17,6 +17,7 @@ Author: Daniel Kroening, [email protected] | |||
| #include <util/exception_utils.h> | |||
| #include <util/pointer_offset_size.h> | |||
| #include <util/simplify_expr.h> | |||
| #include <util/expr_util.h> | |||
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Please sort lexicographically (I'm pretty sure clang-format will block on this)
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| // Temporarily add the state guard | ||
| guard.emplace_back(state.guard.as_expr()); | ||
| const exprt assignment_guard = | ||
| make_and(state.guard.as_expr(), conjunction(guard)); |
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Presumably this was done this way in the name of performance. Have you checked that your change doesn't noticeably slow symex down?
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Before this was adding an exprt to a vector then using this vector to make the and_exprt of the conjunction, now we first make the conjunction and then add the exprt to the vector of the and_exprt operands. So the operation are the same, just in a different order, this shouldn't impact performances.
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@owen-jones-diffblue I just noticed that my change could lead to assignment_guard being TRUE && TRUE so I've added a commit to have make_and handle the constant cases, can you check that?
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It seems good, once I saw from exprt::is_true() that boolean constant exprts must be either true_exprt or false_exprt.
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@romainbrenguier This now needs a rebase, which I guess would also sort out the CI failure (it's a spurious clang-format report). |
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This is only used in symex_assign.cpp so does not need to be exposed.
The with_exprt constructor already sets the type to the array type.
Makes explicit that these won't be changed.
Without this, it is not clear what are the fields of SSA_stept which are required to describe an assignement.
This can be useful in other modules than BDDs.
This allows guard to be constant in the signatures which makes it explicit that it is left unmodified by the function.
This is to avoid generating expressions like TRUE && TRUE
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✔️
Passed Diffblue compatibility checks (cbmc commit: 63e01d9).
Build URL: https://travis-ci.com/diffblue/test-gen/builds/114089912
This introduce an SSA_assignment_stept class to clarify what describes an assignment step (this could be a start to progressively split the SSA_stept class into several more specialized ones) and does some simple clean-up.