All exception break point is stopping for no reason on simulator

Question

This is very annoying, every time I'm trying to debug on the simulator with "all exception break point", app stops for no reason on this line:

return UIApplicationMain(argc, argv, nil, NSStringFromClass([STAppDelegate class]));

Did any one else found him self struggling with this issue?

Thanks!

EDIT

Back trace on first throw:

 thread #1: tid = 0x1d96b, 0x36fbf540 libc++abi.dylib`__cxa_throw, queue = 'com.apple.main-thread', stop reason = breakpoint 3.2
    frame #0: 0x36fbf540 libc++abi.dylib`__cxa_throw
    frame #1: 0x306975cc libFontParser.dylib`TFileDescriptorContext::TFileDescriptorContext(char const*) + 112
    frame #2: 0x306973d8 libFontParser.dylib`TFileDataReference::TFileDataReference(char const*) + 164
    frame #3: 0x306971fc libFontParser.dylib`TFileDataSurrogate::TFileDataSurrogate(char const*, bool) + 188
    frame #4: 0x3069555a libFontParser.dylib`TFont::CreateFontEntitiesForFile(char const*, bool, TSimpleArray<TFont*>&, bool, short, char const*) + 1402
    frame #5: 0x30694a80 libFontParser.dylib`FPFontCreateFontsWithPath + 224
    frame #6: 0x2a5032bc libCGXType.A.dylib`create_private_data_with_path + 12
    frame #7: 0x2a3ca3c4 CoreGraphics`CGFontCreateFontsWithPath + 24
    frame #8: 0x2a4855d6 CoreGraphics`CGFontCreateFontsWithURL + 310
    frame #9: 0x313dfee4 GraphicsServices`AddFontsFromURLOrPath + 68
    frame #10: 0x313e39de GraphicsServices`__Initialize_block_invoke + 934
    frame #11: 0x0121fabe libdispatch.dylib`_dispatch_client_callout + 22
    frame #12: 0x01220750 libdispatch.dylib`dispatch_once_f + 100
    frame #13: 0x313df72c GraphicsServices`Initialize + 196
    frame #14: 0x377944c4 libobjc.A.dylib`_class_initialize + 536
    frame #15: 0x3779a046 libobjc.A.dylib`lookUpImpOrForward + 254
    frame #16: 0x37799f3e libobjc.A.dylib`_class_lookupMethodAndLoadCache3 + 34
    frame #17: 0x377a01f8 libobjc.A.dylib`_objc_msgSend_uncached + 24
    frame #18: 0x2d673b6e UIKit`-[UIStatusBarNewUIForegroundStyleAttributes makeTextFontForStyle:] + 78
    frame #19: 0x2d634d94 UIKit`-[UIStatusBarForegroundStyleAttributes textFontForStyle:] + 104
    frame #20: 0x2d5e767e UIKit`-[UIStatusBarServiceItemView updateForContentType:serviceString:serviceCrossfadeString:maxWidth:actions:] + 390
    frame #21: 0x2d5e74ee UIKit`-[UIStatusBarServiceItemView updateForNewData:actions:] + 186
    frame #22: 0x2d6428d0 UIKit`-[UIStatusBarItemView initWithItem:data:actions:style:] + 324
    frame #23: 0x2d642568 UIKit`-[UIStatusBarLayoutManager _createViewForItem:withData:actions:] + 108
    frame #24: 0x2d5e6f74 UIKit`-[UIStatusBarLayoutManager _prepareEnabledItemType:withEnabledItems:withData:actions:itemAppearing:itemDisappearing:] + 264
    frame #25: 0x2d5e6e22 UIKit`-[UIStatusBarLayoutManager prepareEnabledItems:withData:actions:] + 74
    frame #26: 0x2d5e6c72 UIKit`-[UIStatusBarForegroundView _setStatusBarData:actions:animated:] + 162
    frame #27: 0x2d5e6b96 UIKit`-[UIStatusBarForegroundView setStatusBarData:actions:animated:] + 710
    frame #28: 0x2d671ebe UIKit`__44-[UIStatusBar _prepareToSetStyle:animation:]_block_invoke + 358
    frame #29: 0x2d5fc230 UIKit`+[UIView(Animation) performWithoutAnimation:] + 72
    frame #30: 0x2d66fcf4 UIKit`-[UIStatusBar _prepareToSetStyle:animation:] + 688
    frame #31: 0x2d6579ca UIKit`-[UIStatusBar _requestStyleAttributes:animationParameters:] + 290
    frame #32: 0x2d65696e UIKit`-[UIStatusBar requestStyle:animated:] + 86
    frame #33: 0x2d65559a UIKit`-[UIApplication _createStatusBarWithRequestedStyle:orientation:hidden:] + 406
    frame #34: 0x2d85122a UIKit`-[UIApplication _runWithMainScene:transitionContext:completion:] + 970
    frame #35: 0x2d85bc68 UIKit`__84-[UIApplication _handleApplicationActivationWithScene:transitionContext:completion:]_block_invoke + 36
    frame #36: 0x2d84fc5a UIKit`-[UIApplication workspaceDidEndTransaction:] + 130
    frame #37: 0x3086c0e0 FrontBoardServices`__31-[FBSSerialQueue performAsync:]_block_invoke + 12
    frame #38: 0x2a13782c CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame #39: 0x2a136af0 CoreFoundation`__CFRunLoopDoBlocks + 216
    frame #40: 0x2a13564a CoreFoundation`__CFRunLoopRun + 1714
    frame #41: 0x2a082db0 CoreFoundation`CFRunLoopRunSpecific + 476
    frame #42: 0x2a082bc2 CoreFoundation`CFRunLoopRunInMode + 106
    frame #43: 0x2d653c36 UIKit`-[UIApplication _run] + 558
    frame #44: 0x2d64ea30 UIKit`UIApplicationMain + 1440
  * frame #45: 0x003b4ec2 Stox`main(argc=1, argv=0x01200b08) + 178 at main.m:17

Third:

 thread #1: tid = 0x1d96b, 0x36fbf540 libc++abi.dylib`__cxa_throw, queue = 'com.apple.main-thread', stop reason = breakpoint 3.2
    frame #0: 0x36fbf540 libc++abi.dylib`__cxa_throw
    frame #1: 0x30798c22 libTrueTypeScaler.dylib`ScalerNewBlock(memoryContext*, long, long, void*, unsigned char, unsigned char) + 430
    frame #2: 0x3077e172 libTrueTypeScaler.dylib`OutlineToPath(memoryContext*, fnt_ElementType const*) + 178
    frame #3: 0x3079502a libTrueTypeScaler.dylib`ObtainDesiredOutline(memoryContext*, fnt_ElementType const*, unsigned long, void**) + 10
    frame #4: 0x3077e07c libTrueTypeScaler.dylib`RenderPath(fsg_SplineKey*, memoryContext*, scalerGlyph const*) + 36
    frame #5: 0x3077c980 libTrueTypeScaler.dylib`TTRenderGlyphs + 436
    frame #6: 0x306c5722 libFontParser.dylib`TConcreteFontScaler::CopyGlyphPath(unsigned short, CGAffineTransform const*) const + 378
    frame #7: 0x306a0ce6 libFontParser.dylib`FPFontCopyGlyphPath + 494
    frame #8: 0x2a3abb4a CoreGraphics`CGFontCreateGlyphPath + 30
    frame #9: 0x2a3aba56 CoreGraphics`CGFontCreateGlyphBitmap + 266
    frame #10: 0x2a3b3c1a CoreGraphics`CGGlyphBuilder::create_missing_bitmaps(CGGlyphIdentifier const*, unsigned long, CGGlyphBitmap const**) + 82
    frame #11: 0x2a6fd4dc libRIP.A.dylib`render_glyphs + 172
    frame #12: 0x2a6fcaca libRIP.A.dylib`draw_glyph_bitmaps + 906
    frame #13: 0x2a6fc430 libRIP.A.dylib`ripc_DrawGlyphs + 1108
    frame #14: 0x2a3a1002 CoreGraphics`draw_glyphs + 274
    frame #15: 0x2aaae268 CoreText`DrawSbixGlyphsAtPositions(TFont const*, CGFont*, TCFRef<__CFData const*> const&, unsigned short const*, CGPoint const*, unsigned long, CGContext*, CGAffineTransform, CGAffineTransform) + 1880
    frame #16: 0x2aa6bcce CoreText`CTFontDrawGlyphsWithAdvances + 470
    frame #17: 0x349eba1a UIFoundation`__NSStringDrawingEngine + 6710
    frame #18: 0x349efa64 UIFoundation`-[NSAttributedString(NSExtendedStringDrawing) drawWithRect:options:context:] + 532
    frame #19: 0x2d603370 UIKit`-[UILabel _drawTextInRect:baselineCalculationOnly:] + 4440
    frame #20: 0x2d668ed4 UIKit`-[UILabel drawTextInRect:] + 488
    frame #21: 0x2d668ce8 UIKit`-[UILabel drawRect:] + 84
    frame #22: 0x2d668c70 UIKit`-[UIView(CALayerDelegate) drawLayer:inContext:] + 400
    frame #23: 0x2d045910 QuartzCore`-[CALayer drawInContext:] + 228
    frame #24: 0x2d02f350 QuartzCore`CABackingStoreUpdate_ + 2068
    frame #25: 0x2d110b6c QuartzCore`___ZN2CA5Layer8display_Ev_block_invoke + 52
    frame #26: 0x2d02eb34 QuartzCore`x_blame_allocations + 88
    frame #27: 0x2d02e7e4 QuartzCore`CA::Layer::display_() + 1156
    frame #28: 0x2d012d9c QuartzCore`CA::Layer::display_if_needed(CA::Transaction*) + 200
    frame #29: 0x2d012a60 QuartzCore`CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 24
    frame #30: 0x2d012446 QuartzCore`CA::Context::commit_transaction(CA::Transaction*) + 222
    frame #31: 0x2d012250 QuartzCore`CA::Transaction::commit() + 324
    frame #32: 0x2d5e51c8 UIKit`_afterCACommitHandler + 132
    frame #33: 0x2a137844 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 20
    frame #34: 0x2a134f28 CoreFoundation`__CFRunLoopDoObservers + 276
    frame #35: 0x2a13532a CoreFoundation`__CFRunLoopRun + 914
    frame #36: 0x2a082db0 CoreFoundation`CFRunLoopRunSpecific + 476
    frame #37: 0x2a082bc2 CoreFoundation`CFRunLoopRunInMode + 106
    frame #38: 0x313e7050 GraphicsServices`GSEventRunModal + 136
    frame #39: 0x2d64ea30 UIKit`UIApplicationMain + 1440
  * frame #40: 0x003b4ec2 Stox`main(argc=1, argv=0x01200b08) + 178 at main.m:17

Answer 1

I was just experiencing the same exact problem and tracked down the issue.

Make sure that all fonts that you specify in your Info.plist under Fonts provided by this application are actually in your application bundle.

Answer 2

There's a more accurate way of tracking down the suspect font in your app using the debugger and the fact that it's conveniently stopped at the call.

Step 1: Reproduce the __cxa_throw breakpoint

Usually this happens when instantiating one of (or possibly the first) UIView object in your app. You'll see your debugger has broken and you'll have a stack such as this:

Step 2: Select the entry in the stack trace with the symbol FPFontCreateFontsWithPath

In my case, this entry was line 7 in the stack.

If you take a look at the disassembly, you'll notice the function signature of this entry:

Ah, cool! Looks like it takes some C strings. I betcha one of those is a filepath too!

Step 3: Locate that string in the app memory

I'm running this in a (x86_64) simulator, which on my computer stores the function arguments in some of the registers beginning with r. More details on registers here.

Either press Shift+Command+M or select the "Debug > Debug Workflow > View Memory" option from the menu.

At the bottom of this view, go through the registers one by one and enter the addresses. In my case, r14 contained the path of the file.

Alright, so now I know the font that's messed up. It's looking for HelveticaNeue.ttc. Let's find the reference to that in the project.

Open a terminal, navigate to your project and run:

$ ~/W/X/project> grep -R "HelveticaNeue" ./
.//MyProject/Main.Storyboard:        <array key="HelveticaNeue.ttc">
.//MyProject/Main.Storyboard:            <string>HelveticaNeue</string>
.//MyProject/Main.Storyboard:                                <fontDescription key="fontDescription" name="HelveticaNeue" family="Helvetica Neue" pointSize="18"/>

Awesome, now either switch those to system by replacing name="HelveticaNeue" family="Helvetica Neue" with type="system", open the storyboard and manually edit them or add a reference to the missing font to your app (info.plist and target).

Step 4: Celebrate 🎉 🎊 🍾 🍻

Answer 3

As the backtrace shows, the app didn't stop for no reason. It stopped because an exception was thrown, and it looks like a C++ exception.

Unlike Objective-C, where exceptions should only be thrown as the result of programming errors and therefore are very rare, there is a lot of C++ code around that throws and catches lots of exceptions. In that situation, probably best to only set a breakpoint on Objective-C exceptions, not all exceptions.