CODEWITHSUNDEEP
androidc++android-ndkporting
Dabbler
Dabbler

Reputation: 9863

What causes signal 'SIGILL'?

I'm porting some C++ code to Android using NDK and GCC. The code basically runs. At one point, when debugging in Eclipse, the call

Dabbler::Android::Factory* pFactory = new Dabbler::Android::Factory;

causes this error:

Thread [1] (Suspended: Signal 'SIGILL' received. Description: Illegal instruction.) 
    1 <symbol is not available> 0x812feb44

What does that mean? Has the compiler generated illegal code for some reason? I have a breakpoint in the constructor (which does nothing), and it's not hit. I have already done a full rebuild.

What could I be doing wrong to cause this problem?

Upvotes: 115

Views: 174989

Answers (4)

pkamb
pkamb

Reputation: 34993

LeetCode's online compiler and dev environment generates SIGILL errors for mistakes that do not generate the same error in my desktop IDE.

For example, array access with an out-of-bounds index:

["foo", "bar"][2]

LeetCode's compiler shows only the error:

Runtime Error process exited with signal SIGILL

in a local Xcode playground this same code instead results in the error:

error: Execution was interrupted, reason: EXC_BREAKPOINT (code=1, subcode=0x18f2ea5d8).
The process has been left at the point where it was interrupted, use "thread return -x" to return to the state before expression evaluation.

Only in a full Xcode project compilation and run does it report the actual error:

Thread 1: Fatal error: Index out of range

Upvotes: 6

Max Klint
Max Klint

Reputation: 886

Make sure that all functions with non-void return type have a return statement.

While some compilers automatically provide a default return value, others will send a SIGILL or SIGTRAP at runtime when trying to leave a function without a return value.

Upvotes: 62

Basile Starynkevitch
Basile Starynkevitch

Reputation: 1

It could be some un-initialized function pointer, in particular if you have corrupted memory (then the bogus vtable of C++ bad pointers to invalid objects might give that).

BTW gdb watchpoints & tracepoints, and also valgrind might be useful (if available) to debug such issues. Or some address sanitizer.

Upvotes: 27

trojanfoe
trojanfoe

Reputation: 122391

It means the CPU attempted to execute an instruction it didn't understand. This could be caused by corruption I guess, or maybe it's been compiled for the wrong architecture (in which case I would have thought the O/S would refuse to run the executable). Not entirely sure what the root issue is.

Upvotes: 38

Related Questions