您好，假如下面是我在卡顿时，记录的Thread的堆栈信息：
Backtrace of Thread 10243:

libsystem_kernel.dylib 0x10d86834a mach_msg_trap + 10
CoreFoundation 0x108fd7e85 __CFRunLoopServiceMachPort + 213
CoreFoundation 0x108fd73c2 __CFRunLoopRun + 1730
CoreFoundation 0x108fd6a89 CFRunLoopRunSpecific + 409
Foundation 0x108950e5e -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 274
Foundation 0x1089ce9b7 -[NSRunLoop(NSRunLoop) runUntilDate:] + 87
UIKit 0x10ad9ec95 -[UIEventFetcher threadMain] + 118
Foundation 0x10895e8ac NSThread__start + 1197
libsystem_pthread.dylib 0x10d8a493b _pthread_body + 180
libsystem_pthread.dylib 0x10d8a4887 _pthread_start + 286
libsystem_pthread.dylib 0x10d8a408d thread_start + 13

问题是，我用上面这段信息，根本分析不出什么有价值的信息；
您有何建议？
或者说，用BSBacktraceLogger打出来的log， 还需要结合dsym和atos来符号化吗？

我这打静态库的时候出现编译失败的问题

_bs_backtraceOfThread这个方法在return [resultString copy]之后会出现崩溃EXC_BAD_INSTRUCTION

Skipped building BSBacktraceLogger due to the error:
Dependency "BSBacktraceLogger" has no shared framework schemes for any of the platforms: iOS

在获取堆栈时，有时会出现bs_imageIndexContainingAddress命中不了image，返回成UINT_MAX，，我把对应的address打印出来，内容的长度为16为，一般业务代码为9位

https://github.com/bestswifter/BSBacktraceLogger/blob/master/BSBacktraceLogger/BSBacktraceLogger.m#L318

untime error: unsigned integer overflow: 20274 - 21786 cannot be represented in type 'unsigned long'

for(uint32_t iSym = 0; iSym < symtabCmd->nsyms; iSym++) {
// If n_value is 0, the symbol refers to an external object.
if(symbolTable[iSym].n_value != 0) {
uintptr_t symbolBase = symbolTable[iSym].n_value;
uintptr_t currentDistance = addressWithSlide - symbolBase;
if((addressWithSlide >= symbolBase) &&
(currentDistance <= bestDistance)) {
bestMatch = symbolTable + iSym;
bestDistance = currentDistance;
}
}
}

我的手机型号是iPhoneXR, iOS14.5版本，调用栈如下：
libobjc.A.dylib 0x1bd80f1e0 objc_msgSend + 32
libdispatch.dylib 0x1008fdd90 _dispatch_client_callout + 20
0x0000000000000000 0x8e66190100900e80 0x0 + 10260916293105356416
0x0000000000000000 0xc450230100916ca0 0x0 + 14145844916782197920
0x0000000000000000 0xe21599010090dea0 0x0 + 16291095456666148512
0x0000000000000000 0x75177501a8d301f8 0x0 + 8437341076889731576
0x0000000000000000 0x4e09cb81a8d2a0d0 0x0 + 5623249367492370640
0x0000000000000000 0x800f7b81a8d291c0 0x0 + 9227729958318805440
0x0000000000000000 0xd00cf701c0311734 0x0 + 14991628846501009204
0x0000000000000000 0x1608ce81ab7977e4 0x0 + 1587745924971067364
0x0000000000000000 0x112c2481ab79d054 0x0 + 1237404136966312020
0x0000000000000000 0x106b6981005399d4 0x0 + 1183155329892063700
libdyld.dylib 0x1a89e5cf8 + 4

dispatch_async(dispatch_get_global_queue(0, 0), ^{ // something for (NSInteger i = 0; i < 5000 ; i ++) { NSLog(@"index----- %@",@(i)); NSString * ddd = [KGPrintThreadSnapshoot bs_backtraceOfCurrentThread]; NSLog(@"bs_backtraceOfCurrentThread----- %@",ddd); } });

打印结果：
index==1
bs_backtraceOfCurrentThread----- Backtrace of Thread 3587:
libsystem_kernel.dylib 0x111127f72 mach_msg_trap + 10
index==2的时候 就准确了

大神你好.拜读代码和博客,写的都非常详细,对我帮助很大.十分感谢~
现在有个小问题:代码173行和179行有两次主线程判断,能否解释一下为什么这样做?是有什么特殊的处理吗?
个人理解第一个主线程判断 return 掉以后,第二个判断应该是走不到的.
望解答~

if ([nsthread isMainThread]) {
    return (thread_t)main_thread_id;
}

for (int i = 0; i < count; ++i) {
    pthread_t pt = pthread_from_mach_thread_np(list[i]);
    if ([nsthread isMainThread]) {
        if (list[i] == main_thread_id) {
            return list[i];
        }
    }
    if (pt) {
        name[0] = '\0';
        pthread_getname_np(pt, name, sizeof name);
        if (!strcmp(name, [nsthread name].UTF8String)) {
            [nsthread setName:originName];
            return list[i];
        }
    }
}

APP发布后如果用这个收集堆栈信息，在使用符号表解析可吗？解析后内容准确吧。

thread_t bs_machThreadFromNSThread(NSThread *nsthread) {
    char name[256];
    mach_msg_type_number_t count;
    thread_act_array_t list;
    task_threads(mach_task_self(), &list, &count);
    
    NSTimeInterval currentTimestamp = [[NSDate date] timeIntervalSince1970];
    NSString *originName = [nsthread name];
    [nsthread setName:[NSString stringWithFormat:@"%f", currentTimestamp]];
    
    if ([nsthread isMainThread]) {
        return (thread_t)main_thread_id;
    }
    
    for (int i = 0; i < count; ++i) {
        pthread_t pt = pthread_from_mach_thread_np(list[i]);
        if ([nsthread isMainThread]) {
            if (list[i] == main_thread_id) {
                return list[i];
            }
        }
        if (pt) {
            name[0] = '\0';
            pthread_getname_np(pt, name, sizeof name);
            if (!strcmp(name, [nsthread name].UTF8String)) {
                [nsthread setName:originName];
                return list[i];
            }
        }
    }
    
    [nsthread setName:originName];
    return pthread_mach_thread_np(pthread_self());
}

this method will cause mach port leak

系统提供的dladdr方法是线程安全的，而代码中的fl_dladdr其实底层调用的也是系统提供的_dyld_get_image_header和_dyld_get_image_name等方法，而这些方法是线程不安全的，经过我本人的实验对比，fl_dladdr返回的symbolbuffer和dladdr返回的结果是一样的，不清楚作者是出于什么样的考虑自己重写了一个fl_dladdr方法。

抱拳抱拳抱拳