Error when profiling

[Nicholas Wilson via Digitalmars-d-learn]

On Saturday, 31 January 2015 at 14:12:59 UTC, Phil wrote:
> When trying to run my program with profiling enabled it dies 
> before the first line of my main function runs. Everything 
> works fine without profiling. I get the following stack trace:
>
>  thread #1: tid = 0x38de4, 0x000000010008d985 
> vision_entry`gc_malloc + 49, queue = 'com.apple.main-thread', 
> stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
>     frame #0: 0x000000010008d985 vision_entry`gc_malloc + 49
> vision_entry`gc_malloc + 49:
> -> 0x10008d985:  movq   (%rdi), %rbx
>    0x10008d988:  callq  *0x60(%rbx)
>    0x10008d98c:  popq   %rbx
>    0x10008d98d:  movq   %rbp, %rsp
> (lldb) thread backtrace
> * thread #1: tid = 0x38de4, 0x000000010008d985 
> vision_entry`gc_malloc + 49, queue = 'com.apple.main-thread', 
> stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
>   * frame #0: 0x000000010008d985 vision_entry`gc_malloc + 49
>     frame #1: 0x00000001000908f5 vision_entry`_d_newclass + 117
>     frame #2: 0x00000001000b4b28 
> vision_entry`D3std9exception7bailOutFNaNfAyamxAaZv + 40
>     frame #3: 0x00000001000b4d06 
> vision_entry`D3std9exception14__T7enforceTbZ7enforceFNaNfbLAxaAyamZb 
> + 94
>     frame #4: 0x00000001000c4df6 
> vision_entry`D3std5stdio4File17LockingTextWriter6__ctorMFNcNeKS3std5stdio4FileZS3std5stdio4File17LockingTextWriter 
> + 86
>     frame #5: 0x00000001000c4f19 
> vision_entry`D3std5stdio4File17lockingTextWriterMFZS3std5stdio4File17LockingTextWriter 
> + 41
>     frame #6: 0x0000000100002c74 
> vision_entry`D3std5stdio4File15__T8writeflnTaZ8writeflnMFxAaZv 
> + 124 at stdio.d:1238
>     frame #7: 0x0000000100000c06 vision_entry`_Dmain + 86 at 
> stdio.d:2727
>     frame #8: 0x000000010009060c 
> vision_entry`D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZ9__lambda1MFZv 
> + 40
>     frame #9: 0x0000000100090551 
> vision_entry`D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ7tryExecMFMDFZvZv 
> + 45
>     frame #10: 0x00000001000905b1 
> vision_entry`D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ6runAllMFZv + 
> 45
>     frame #11: 0x0000000100090551 
> vision_entry`D2rt6dmain211_d_run_mainUiPPaPUAAaZiZ7tryExecMFMDFZvZv 
> + 45
>     frame #12: 0x00000001000904cd vision_entry`_d_run_main + 433
>     frame #13: 0x0000000100000d29 vision_entry`main + 65
>     frame #14: 0x00007fff883a45c9 libdyld.dylib`start + 1
>
> Does anyone have any ideas of what could have caused this?

What is the source code of your main function?
I ask because it looks like it did. frame 13 is C main. frames 12 
- 8 are compiler generated.
Frame 7 is  D main.
>     frame #7: 0x0000000100000c06 vision_entry`_Dmain + 86 at 
> stdio.d:2727
Frame 6 is std.stdio.writefln(...)
Frame 5 is the acquisition of the locking text writer
frame 4 is the constructor of the locking text writer. THIS IS 
WHERE THE EXCEPTION IS THROWN.
as is evident by frame 3.
> vision_entry`D3std9exception14__T7enforceTbZ7enforceFNaNfbLAxaAyamZb 
> + 94
where the locking text writer is enforcing some condition. 
(possibly that it received the correct amour of arguments)
Frame 2 is the enforce bailing out
Frames 1 is bailout() throwing a _new_ exception. 
_d_newclass(exception)
frame 0 is the gc_malloc attempting to allocate the memory for 
the exception.
and hits a
> stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
> -> 0x10008d985:  movq   (%rdi), %rbx (rbx = *rdi)
null pointer somewhere.

your main function looks like

int main(string[] args)
{
     writefln(...); // Double check whats going on here
     ...
     return 0;
}
try
int main(string[] args)
{
     try writefln(...); // Double check whats going on here
     catch(exception e)
     {
          writeln("caught some exception"); // alternatively use 
printf/puts if written also fails
     }
     ...
     return 0;
}
and you will see
caught some exception instead of the stack trace.

Are you profiling with an external profiler or using the compiler 
to emit profile statistics?
My only guess is that there is a bug in the compiler's inserted 
profiling code.
perhaps someone else will be able to help.

Nic