diff --git a/jbmc/regression/jbmc-generics/constant_propagation/Generic.class b/jbmc/regression/jbmc-generics/constant_propagation/Generic.class new file mode 100644 index 00000000000..aa709de18f1 Binary files /dev/null and b/jbmc/regression/jbmc-generics/constant_propagation/Generic.class differ diff --git a/jbmc/regression/jbmc-generics/constant_propagation/GenericSub.class b/jbmc/regression/jbmc-generics/constant_propagation/GenericSub.class new file mode 100644 index 00000000000..208befc45c1 Binary files /dev/null and b/jbmc/regression/jbmc-generics/constant_propagation/GenericSub.class differ diff --git a/jbmc/regression/jbmc-generics/constant_propagation/Test.class b/jbmc/regression/jbmc-generics/constant_propagation/Test.class new file mode 100644 index 00000000000..c339d158cf7 Binary files /dev/null and b/jbmc/regression/jbmc-generics/constant_propagation/Test.class differ diff --git a/jbmc/regression/jbmc-generics/constant_propagation/Test.java b/jbmc/regression/jbmc-generics/constant_propagation/Test.java new file mode 100644 index 00000000000..2c71fc754a0 --- /dev/null +++ b/jbmc/regression/jbmc-generics/constant_propagation/Test.java @@ -0,0 +1,27 @@ +public class Test { + public static void main() { + Generic g = new GenericSub(); + + int x = 0; + for(int i = 0; i < 1000; ++i) + x += g.get(); + + assert x == 0; + } +} + +class Generic { + T key; + int x; + + public int get() { return 0; } + + public Generic() { + key = null; + x = 5; + } +} + +class GenericSub extends Generic { + public int get() { return x; } +} diff --git a/jbmc/regression/jbmc-generics/constant_propagation/test.desc b/jbmc/regression/jbmc-generics/constant_propagation/test.desc new file mode 100644 index 00000000000..31756c1b722 --- /dev/null +++ b/jbmc/regression/jbmc-generics/constant_propagation/test.desc @@ -0,0 +1,12 @@ +CORE +Test.class +--function Test.main --show-vcc +^EXIT=0$ +^SIGNAL=0$ +^\{-\d+\} symex_dynamic::dynamic_object1#3 = \{ \{ \{ "java::GenericSub" \}, NULL, 0 \} \}$ +^\{-\d+\} symex_dynamic::dynamic_object1#4 = \{ \{ \{ "java::GenericSub" \}, NULL, 5 \} \}$ +-- +byte_extract_(big|little)_endian +-- +The use of generics should not result in any byte_extract operations being +generated for this test. diff --git a/regression/cbmc/Pointer_byte_extract4/program-only.desc b/regression/cbmc/Pointer_byte_extract4/program-only.desc new file mode 100644 index 00000000000..7b738a3b40b --- /dev/null +++ b/regression/cbmc/Pointer_byte_extract4/program-only.desc @@ -0,0 +1,12 @@ +CORE +main.c + +^EXIT=0$ +^SIGNAL=0$ +-- +^warning: ignoring +: dynamic_object1#\d+\) WITH +-- +The above pattern makes sure we don't have a conditional choice of objects +within a "with" expression. We avoid having this by running the simplifier after +dereferencing. diff --git a/src/goto-symex/symex_dereference.cpp b/src/goto-symex/symex_dereference.cpp index 20f65da8854..0a7fd38f956 100644 --- a/src/goto-symex/symex_dereference.cpp +++ b/src/goto-symex/symex_dereference.cpp @@ -16,6 +16,7 @@ Author: Daniel Kroening, kroening@kroening.com #include #include #include +#include #include #include @@ -363,4 +364,30 @@ void goto_symext::dereference(exprt &expr, statet &state) // dereferencing may introduce new symbol_exprt // (like __CPROVER_memory) expr = state.rename(std::move(l1_expr), ns); + + // Dereferencing is likely to introduce new member-of-if constructs -- + // for example, "x->field" may have become "(x == &o1 ? o1 : o2).field." + // Run expression simplification, which converts that to + // (x == &o1 ? o1.field : o2.field)) + // before applying field sensitivity. Field sensitivity can then turn such + // field-of-symbol expressions into atomic SSA expressions instead of having + // to rewrite all of 'o1' otherwise. + // Even without field sensitivity this can be beneficial: for example, + // "(b ? s1 : s2).member := X" results in + // (b ? s1 : s2) := (b ? s1 : s2) with (member := X) + // and then + // s1 := b ? ((b ? s1 : s2) with (member := X)) : s1 + // when all we need is + // s1 := s1 with (member := X) [and guard b] + // s2 := s2 with (member := X) [and guard !b] + do_simplify(expr); + + if(symex_config.run_validation_checks) + { + // make sure simplify has not re-introduced any dereferencing that + // had previously been cleaned away + INVARIANT( + !has_subexpr(expr, ID_dereference), + "simplify re-introduced dereferencing"); + } }