Hello,
All right, now I know how to print out GIMPLE internal functions. I do the
following and it won't crash:
const gcall* a = as_a <const gcall *> (stmt);
const char * tt =
internal_fn_name(gimple_call_internal_fn(a));
However, just a follow-up question, how can I actually distinguish GIMPLE
internal functions with "normal" function? Thank you very much!
Best,
Shuai
On Tue, Jun 9, 2020 at 3:50 PM Shuai Wang <wangshuai...@gmail.com> wrote:
> Dear Richard,
>
> Thank you for the information. Yes, that makes sense to me.
>
> Nevertheless, is there any chance that I can still pinpoint this special
> function call? Currently I can iterate all GIMPLE call statements, but how
> to exactly figure out ASAN_MARK seems quite obscure.
>
> Thank you!
>
> Best,
> Shuai
>
> On Tue, Jun 9, 2020 at 3:48 PM Richard Biener <richard.guent...@gmail.com>
> wrote:
>
>> 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
>>
>
