On Tue, Jun 9, 2020 at 3:38 AM Shuai Wang via Gcc <gcc@gcc.gnu.org> wrote:
>
> Hello!
>
> I am writing to report a potential bug I encountered when playing with the
> GIMPLE IR. I enabled the ASan and would like to print out all ASAN_MARK
> statements for the following simple code:
>
> int main(int argc ,char **argv)
> {
> int stack_array[100];
> stack_array[1] = 100;
> stack_array[argc + 12]; // an ASan check, namely, ASAN_MARK, will
> be inserted at this point
> }
>
> And I am using the following code snippet (basically derived from this
> post
> <https://stackoverflow.com/questions/29346772/print-called-function-name-using-gcc-plugin>)
> to print out all function calls, including ASAN_MARK:
>
> if (is_gimple_call(stmt)){
> tree current_fn_decl = gimple_call_fndecl(stmt);
> const char* name = get_name(current_fn_decl);
> cerr << " Function : " << name << " is called \n";
> }
>
> However, I note that some internal exceptions are encountered, when I
> use gcc version 7.4, 8.3, and also 9.3:
>
> test.c: In function ‘main’:
> test.c:9:5: internal compiler error: Segmentation fault
> 9 | int main(int argc ,char **argv)
> | ^~~~
> 0xab88bf crash_signal
> ../../gcc-9.3.0/gcc/toplev.c:326
> 0xcfc836 location_wrapper_p(tree_node const*)
> ../../gcc-9.3.0/gcc/tree.h:3812
> 0xcfc836 tree_nop_conversion
> ../../gcc-9.3.0/gcc/tree.c:12850
> 0xcfc836 tree_strip_nop_conversions(tree_node*)
> ../../gcc-9.3.0/gcc/tree.c:12888
> 0xcfc836 get_name(tree_node*)
> ../../gcc-9.3.0/gcc/tree.c:12559
> 0x7f9466d86bb7 execute
>
> /home/shuaiw/work/sanitizer_reduction_gcc/demo/walk_gimple/walk_gimple.cc:61
> Please submit a full bug report,
> with preprocessed source if appropriate.
> Please include the complete backtrace with any bug report.
> See <https://gcc.gnu.org/bugs/> for instructions.
> Makefile:10: recipe for target 'test' failed
> make: *** [test] Error 1
>
>
> I think the issue is due to ASAN_MARK, because when I comment out that
> particular array access which induces the ASAN_MARK, all other function
> calls, including ASan related functions, __builtin___asan_init
> and __builtin___asan_version_mismatch_check_v8, and be smoothly printed out
> with no issue.
>
> Can I interpret it as a bug or somewhat? Any suggestions are welcomed.
> Thank you very much.
ASAN_MARK is likely an internal function which does not have a function
declaration so you feed get_name a NULL pointer.
>
> Best,
> Shuai
