iOS 启动优化 二进制重排
1. 在Build Settings中添加编译选项Other C Flags增加`-fsanitize-coverage=func,trace-pc-guard
如果是OC Swift混编，
则在Other Swift Flags增加`-sanitize-coverage=func`,`-sanitize=undefined
2.统计程序启动的函数执行情况在首页的viewDidAppear函数中加上生成orderFile的函数，然后运行app
-(void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated];
[HTClangTrace generateOrderFile];
}
会在app的沙盒的tmp目录下生成，
htclangtrace.order的文件 ,获取tmp 下的htclangtrace.order 导入工程
3. 在Build Settings中搜索Order File 设置为htclangtrace.order的路径
HTClangTrace.h 文件如下
#import <Foundation/Foundation.h>
NS_ASSUME_NONNULL_BEGIN
@interface HTClangTrace : NSObject
/// 生成trace.order文件；一般我们要检测启动前执行的函数，所以放到首页的viewDidAppear中调用该函数+ (void)generateOrderFile;
@endNS_ASSUME_NONNULL_END
HTClangTrace.m 文件代码如下
// // HTClangTrace.m // HTScore_iOS // // Created by muxinjian on 2020/6/3. // Copyright © 2020 huatu. All rights reserved. // #import "HTClangTrace.h" #import <dlfcn.h> #import <libkern/OSAtomic.h> @implementation HTClangTrace void __sanitizer_cov_trace_pc_guard_init(uint32_t *start, uint32_t *stop) { static uint64_t N; // Counter for the guards. if (start == stop || *start) return; // Initialize only once. for (uint32_t *x = start; x < stop; x++) *x = ++N; // Guards should start from 1. } //原子队列 static OSQueueHead symbolList = OS_ATOMIC_QUEUE_INIT; //定义符号结构体 typedef struct { void *pc; void *next; } SymbolNode; void __sanitizer_cov_trace_pc_guard(uint32_t *guard) { if (!*guard) return; void *PC = __builtin_return_address(0); SymbolNode *node = malloc(sizeof(SymbolNode)); *node = (SymbolNode){PC, NULL}; OSAtomicEnqueue(&symbolList, node, offsetof(SymbolNode, next)); } + (void)generateOrderFile { NSMutableArray <NSString *> *symbolNames = [NSMutableArray array]; while (YES) { SymbolNode * node = OSAtomicDequeue(&symbolList, offsetof(SymbolNode, next)); if (node == NULL) { break; } Dl_info info; dladdr(node->pc, &info); NSString *name = @(info.dli_sname); // 判断是不是oc方法，是的话直接加入符号数组 BOOL isInstanceMethod = [name hasPrefix:@"-["]; BOOL isClassMethod = [name hasPrefix:@"+["]; BOOL isObjc = isInstanceMethod || isClassMethod; NSString * symbolName = isObjc ? name: [@"_" stringByAppendingString:name]; [symbolNames addObject:symbolName]; } // 取反:将先调用的函数放到前面 NSEnumerator * emt = [symbolNames reverseObjectEnumerator]; // 去重：由于一个函数可能执行多次，__sanitizer_cov_trace_pc_guard会执行多次，就加了重复的了，所以去重一下 NSMutableArray<NSString *> *funcs = [NSMutableArray arrayWithCapacity:symbolNames.count]; NSString *name; while (name = [emt nextObject]) { if (![funcs containsObject:name]) { [funcs addObject:name]; } } // 由于trace了所有执行的函数，这里我们就把本函数移除掉 [funcs removeObject:[NSString stringWithFormat:@"%s",__FUNCTION__]]; // 写order文件 NSString *funcStr = [funcs componentsJoinedByString:@"\n"]; NSString *filePath = [NSTemporaryDirectory() stringByAppendingPathComponent:@"htclangtrace.order"]; NSData *fileContents = [funcStr dataUsingEncoding:NSUTF8StringEncoding]; [[NSFileManager defaultManager] createFileAtPath:filePath contents:fileContents attributes:nil]; if ([[NSFileManager defaultManager] fileExistsAtPath:filePath]){ NSLog(@"orderPath:%@",filePath); }else{ NSLog(@"生成orderPath失败"); } } #pragma mark - Util + (BOOL)isObjcMethodBySymbolName:(NSString *)symbolName { BOOL isInstanceMethod = [symbolName hasPrefix:@"-["]; BOOL isClassMethod = [symbolName hasPrefix:@"+["]; return isInstanceMethod || isClassMethod; } @end
