I am using the Z3 C api in java with jna. I often get an invalid memory access, but only with the windows (.dll) and mac os (.dylib) libraries. It does not happen when I use the linux one (.so).
I temporarily solved this problem never calling the dec_ref procedures, both for ast and for all the other objects (I still call the inc_ref procs, and I use the mk_context_rc at the beginning). Of course this solution is not sustainable.
I guess it is due to the memory management somewhere. Even if I just use the mk_context it still crashes.
In the thread JNA simple function call works on linux (x64) but not on windows (x86) the user experienced a similar problem, and it turned out it was due to some compiling configuration.
This is the exception I get (on Mac OS X 10.6.8)
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x000000000000000c
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
and this is the trace of the failure
Thread 0 Crashed: Dispatch queue: com.apple.main-thread
0 libz3.dylib 0x00000001250d4d64 unsigned int ast_array_hash<expr>(expr* const*, unsigned int, unsigned int) + 244
1 libz3.dylib 0x00000001250cb16a ast_manager::register_node_core(ast*) + 36
2 libz3.dylib 0x00000001250cbeae ast_manager::mk_app_core(func_decl*, unsigned int, expr* const*) + 134
3 libz3.dylib 0x00000001250cc30d ast_manager::mk_app(func_decl*, unsigned int, expr* const*) + 749
4 libz3.dylib 0x000000012528c194 map_proc::reconstruct(app*) + 214
5 libz3.dylib 0x00000001254830b8 void for_each_expr_core<qe::lift_foreign_vars, obj_mark<expr, bit_vector, default_t2uint<expr> >, false, false>(qe::lift_foreign_vars&, obj_mark<expr, bit_vector, default_t2uint<expr> >&, expr*) + 760
6 libz3.dylib 0x00000001254832c9 qe::lift_foreign_vars::lift(obj_ref<expr, ast_manager>&) + 61
7 libz3.dylib 0x00000001254833a6 qe::datatype_plugin::simplify(obj_ref<expr, ast_manager>&) + 92
8 libz3.dylib 0x000000012546b1a7 qe::quant_elim_plugin::check(unsigned int, app* const*, expr*, obj_ref<expr, ast_manager>&, bool, ref_vector<app, ast_manager>&, qe::def_vector*) + 535
9 libz3.dylib 0x000000012546b8f9 qe::quant_elim_new::eliminate_block(unsigned int, app* const*, obj_ref<expr, ast_manager>&, ref_vector<app, ast_manager>&, bool, qe::def_vector*) + 445
10 libz3.dylib 0x000000012545f2cb qe::quant_elim_new::eliminate_exists(unsigned int, app* const*, obj_ref<expr, ast_manager>&, ref_vector<app, ast_manager>&, bool, qe::def_vector*) + 67
11 libz3.dylib 0x0000000125462170 qe::quant_elim_new::eliminate_exists_bind(unsigned int, app* const*, obj_ref<expr, ast_manager>&) + 88
12 libz3.dylib 0x000000012545c0ba qe::expr_quant_elim::elim(obj_ref<expr, ast_manager>&) + 1012
13 libz3.dylib 0x000000012545cb75 qe::expr_quant_elim::operator()(expr*, expr*, obj_ref<expr, ast_manager>&) + 113
14 libz3.dylib 0x000000012548b993 qe_tactic::imp::operator()(ref<goal> const&, sref_buffer<goal>&, ref<model_converter>&, ref<proof_converter>&, obj_ref<dependency_manager<ast_manager::expr_dependency_config>::dependency, ast_manager>&) + 783
15 libz3.dylib 0x00000001255debfa cleanup_tactical::operator()(ref<goal> const&, sref_buffer<goal>&, ref<model_converter>&, ref<proof_converter>&, obj_ref<dependency_manager<ast_manager::expr_dependency_config>::dependency, ast_manager>&) + 14
16 libz3.dylib 0x00000001255d5e3d exec(tactic&, ref<goal> const&, sref_buffer<goal>&, ref<model_converter>&, ref<proof_converter>&, obj_ref<dependency_manager<ast_manager::expr_dependency_config>::dependency, ast_manager>&) + 109
17 libz3.dylib 0x0000000125070ed8 _tactic_apply + 680
18 libz3.dylib 0x00000001250711d9 Z3_tactic_apply + 105
19 jna4404318687023840668.tmp 0x000000010a00cd1c ffi_call_unix64 + 76
20 jna4404318687023840668.tmp 0x000000010a00c884 ffi_call + 644
21 jna4404318687023840668.tmp 0x000000010a003ca5 Java_com_sun_jna_Native_ffi_1prep_1cif + 1605
22 jna4404318687023840668.tmp 0x000000010a004282 Java_com_sun_jna_Native_invokePointer + 34
23 ??? 0x00000001031cfd2e 0 + 4347198766
24 ??? 0x00000001031cd658 0 + 4347188824
25 ??? 0xffb89c44ff5c4272 0 + 18426649695542329970
maybe they they can be useful to understand what I am doing wrong
The exception was raised because my main program and the java garbage collector were accessing Z3 concurrently. I solved just making the Library object thread-safe, wrapping it with the method Native.synchronizedLibrary