OSX - NSLog prevents application crash in debug mode - objective-c

Question

Developing an app for OSX. There's still bugs and it crashes in release builds.
However, it runs in debug builds, when there's a blank NSLog statement in a few spots. If the NSLog statements are removed, the app crashes on run.
The first statement, in a run loop (prints calculated ticks and drawn frames, it simulates a fluid in an NSView)
NSLog(#"%d ticks, %d frames", ticks, frames);
The second statement, in the tick method that gets called every loop,
NSLog(#"");
In debug mode, running from Xcode, it works just fine with these two statements. If either is removed, it crashes. After several hours searching, I can't find any reference to apps crashing without blank NSLog statements.
Edit: The final question is: Is there anything I should look out for that might be causing this?
Edit 2: The run and tick methods are
-(void) run {
timeval start = gettime();
timeval end = gettime();
float dt = 1./60;
self.E.dt = dt;
float tick = 1e6*dt;
float unprocessed;
int ticks = 0;
int frames = 0;
timeval now;
while ( TRUE ) {
now = gettime();
unprocessed += diff(end, now)/tick;
end = now;
BOOL shouldRender = true; // set false to limit framerate to tickrate
while ( unprocessed >= 1 ) {
ticks++;
[self tick];
unprocessed -= 1;
shouldRender = true;
}
if ( shouldRender ) {
frames++;
}
if ( diff(start, gettime()) > 1000000 ) {
start.tv_sec += 1;
NSLog(#"%d ticks, %d frames", ticks, frames);
frames = 0;
ticks = 0;
}
}
}
-(void) tick {
NSLog(#"");
NSDictionary* fs = [NSDictionary dictionaryWithObjectsAndKeys:self.u, #"u", self.v, #"v", self.p, #"p", self.T, "#T", nil];
NSDictionary* gs = [self.E evolve:fs];
[self.u swap:[gs objectForKey:#"u"]];
[self.v swap:[gs objectForKey:#"v"]];
[self.p swap:[gs objectForKey:#"p"]];
[self.T swap:[gs objectForKey:#"T"]];
[self.view setNeedsDisplay:YES];
}
Edit 3: This is clearly an issue with LLVM. When I compile with GCC, I get no crash. Unfortunately there's an extraordinary amount of memory leaks now due to no ARC. Confusion level increased.
Edit 4: Backtrace
Crashed Thread: 2
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000010
External Modification Warnings:
Debugger attached to process.
VM Regions Near 0x10:
-->
__TEXT 0000000103a9b000-0000000103a9c000 [ 4K] r-x/rwx SM=COW /Users/USER/Library/Developer/Xcode/DerivedData/Splash-ahjwbarsbqqbuzfcnxstxpslekdi/Build/Products/Debug/Splash.app/Contents/MacOS/Splash
Application Specific Information:
objc_msgSend() selector name: copy
objc[32100]: garbage collection is OFF
Thread 2 Crashed:
0 libobjc.A.dylib 0x00007fff8e43ee90 objc_msgSend + 16
1 com.apple.CoreFoundation 0x00007fff87edf8ac -[__NSPlaceholderDictionary initWithObjects:forKeys:count:] + 668
2 com.apple.CoreFoundation 0x00007fff87efcd13 +[NSDictionary dictionaryWithObjectsAndKeys:] + 1203
3 com.mbarriault.Splash 0x0000000103a9d488 -[Game tick] + 328 (Game.m:95)
4 com.mbarriault.Splash 0x0000000103a9d2a9 -[Game run] + 361 (Game.m:76)
5 com.apple.Foundation 0x00007fff9020874e -[NSThread main] + 68
6 com.apple.Foundation 0x00007fff902086c6 __NSThread__main__ + 1575
7 libsystem_c.dylib 0x00007fff8dba18bf _pthread_start + 335
8 libsystem_c.dylib 0x00007fff8dba4b75 thread_start + 13
Thread 2 crashed with X86 Thread State (64-bit):
rax: 0x0000000103aa5a00 rbx: 0x0000000000000004 rcx: 0x0000000000000000 rdx: 0x0000000000000000
rdi: 0x0000000103aa3071 rsi: 0x00007fff8f9ea7d0 rbp: 0x0000000107b47970 rsp: 0x0000000107b47900
r8: 0x0000000000000004 r9: 0x0000000103aa5ab0 r10: 0x0000000000000001 r11: 0x0000000000000000
r12: 0x0000000000000003 r13: 0x0000000107b47928 r14: 0x0000000107b479a0 r15: 0x0000000107b47980
rip: 0x00007fff8e43ee90 rfl: 0x0000000000010202 cr2: 0x0000000000000010
Logical CPU: 3
I removed ID information and the logs for threads that didn't crash, as the whole log went over the post length limit.
Edit 5: Changing the dictionary creation from NSDictionary:dictionaryWithObjectsAndKeys: to NSDictionary:dictionaryWithObjects:forKeys: seems to have fixed all my problems. I'm not entirely certain why, but I'll take it! Thanks everyone!
Edit 6: The correct answer, believe if you will, was a simple typo in a string.

Answer 1

From the look of the backtrace it is crashing when allocating the NSDictionary. Probably one of the object references being used to initialize the NSDictionary is invalid. If you post code from the tick method it could help narrow down what the problem is. Also, if you try debugging with NSZombie on it could tell us which object type it is crashing on.
Edit:
OK. Now that I see the tick code, I can see the problem. I didn't see it at first, but you are using the c-string "#T", which you probably intended to be #"T".