Low Level iOS

This repo is mostly my study notes about low level iOS.

Topics

• Mach-O Parser - writing a Mach-O format parser while learning it
  • LC_SEGMENT_64 - segments and sections
  • LC_SYMTAB - symbol table
  • LC_DYSYMTAB - dynamic symbol table
  • LC_DYLD_INFO(_ONLY) - information for dyld
  • LC_DYLD_CHAINED_FIXUPS - the new way to encode dyld info
  • LC_DYLD_EXPORTS_TRIE - the new command for exported symbols
  • LC_DYLD_ENVIRONMENT - embed environment variables in the binary
  • LC_LINKER_OPTION - auto linking
  • LC_BUILD_VERSION - platform requirements
  • LC_MAIN - the entry point of an executable
  • LC_ENCRYPTION_INFO_64 - FairPlay encryption
  • LC_FUNCTION_STARTS - function addresses
  • LC_*_DYLIB and LC_RPATH - dylib related load commands
  • LC_CODE_SIGNATURE - code signing and code signature format
• Building
  • Build iOS App - build and debug an iOS app without an IDE
  • Build Swift Macros
  • Mixed Language Compiling
  • Module Map - common formats of module.modulemap
  • Import Search Path - how import search path (-I) affects build time
  • Swift Generated ObjC Header
  • Dead Code Elimination
  • Swift Source Info (.swiftsourceinfo)
• Dynamic Linking
  • How does dynamic linking works
  • Exported Symbols - details of how exported symbols are stored
  • Binding Info - details of binding opcodes
  • Chained Fixups - the new way to store dyld info
  • Dynamic Interposing - replace function implementation at runtime
• Testing
  • Behind the scenes: iOS Testing
  • Behind the scenes: Code Coverage
  • Code Coverage on Test Crash
  • [Archived] XCTest
• Xcode
  • Behind the scenes: SwiftUI Previews
  • Xcode.app Directory Structure