通过link map文件可以直观的看到那些文件占用的包的大小。这是我分析之后的文件，可以直观的看出那些东西占用了多少的内存。
build setting 中 设置 write Link Map 文件。
1.首先列出来的是目标文件列表(中括号内为文件编号)： # Path: /Users/mxr/Library/Developer/Xcode/DerivedData/huashida_home.xcodeproj-fvbzvmahuzlfgqbzehannctanrbl/Build/Products/Debug-iphoneos/4dBookCity.app/4dBookCity # Arch: arm64 # Object files: [ 0] linker synthesized [ 1] /Users/mxr/Library/Developer/Xcode/DerivedData/huashida_home.xcodeproj-fvbzvmahuzlfgqbzehannctanrbl/Build/Intermediates.noindex/huashida_home.build/Debug-iphoneos/4dBookCity.build/Objects-normal/arm64/Bulk_Arrays_12.o [ 2] /Users/mxr/Library/Developer/Xcode/DerivedData/huashida_home.xcodeproj-fvbzvmahuzlfgqbzehannctanrbl/Build/Intermediates.noindex/huashida_home.build/Debug-iphoneos/4dBookCity.build/Objects-normal/arm64/MXRSnapLearnInviteView.o
2.接着是一个段表，描述各个段在最后编译成的可执行文件中的偏移位置及大小，包括了代码段（__TEXT，保存程序代码段编译后的机器码）和数据段（__DATA，保存变量值） # Sections: # Address Size Segment Section 0x100005B00 0x0304A29C __TEXT __text 0x10304FD9C 0x00004BC0 __TEXT __stubs 0x10305495C 0x000044E8 __TEXT __stub_helper 0x103058E50 0x0021563C __TEXT __cstring 0x10326E48C 0x000AD400 __TEXT __objc_methname 0x10331B88C 0x0000E6BA __TEXT __objc_classname 0x103329F46 0x000166E3 __TEXT __objc_methtype 0x103340640 0x002A0B60 __TEXT __const 0x1035E11A0 0x001346D4 __TEXT __gcc_except_tab 0x103715874 0x00008C78 __TEXT __ustring 0x10371E4EC 0x0004D80C __TEXT __unwind_info 0x10376BCF8 0x00000300 __TEXT __eh_frame 0x10376C000 0x000015D8 __DATA __got 0x10376D5D8 0x00003280 __DATA __la_symbol_ptr 0x103770858 0x00001838 __DATA __mod_init_func 0x103772090 0x000FF7F8 __DATA __const 0x103871888 0x0006F9C0 __DATA __cfstring 0x1038E1248 0x00004778 __DATA __objc_classlist 0x1038E59C0 0x00000290 __DATA __objc_nlclslist 0x1038E5C50 0x00000708 __DATA __objc_catlist 0x1038E6358 0x00000038 __DATA __objc_nlcatlist 0x1038E6390 0x00000910 __DATA __objc_protolist 0x1038E6CA0 0x00000008 __DATA __objc_imageinfo 0x1038E6CA8 0x00206C58 __DATA __objc_const 0x103AED900 0x00027F28 __DATA __objc_selrefs 0x103B15828 0x000000C0 __DATA __objc_protorefs 0x103B158E8 0x000041B8 __DATA __objc_classrefs 0x103B19AA0 0x000030C0 __DATA __objc_superrefs 0x103B1CB60 0x0000BB54 __DATA __objc_ivar 0x103B286B8 0x0002CB00 __DATA __objc_data 0x103B551C0 0x01D52748 __DATA __data 0x1058A7920 0x00714878 __DATA __bss 0x105FBD000 0x0012B978 __DATA __common
首列是数据在文件的偏移位置，第二列是这一段占用大小，第三列是段类型，代码段和数据段，第四列是段名称。 每一行的数据都紧跟在上一行后面，如第二行__stubs的地址0x10304FD9C就是第一行__text的地址0x100005B00加上大小0x0304A29C，整个可执行文件大致数据分布就是这样。
3.接着就是按上表顺序，列出具体的按每个文件列出每个对应字段的位置和占用空间 # Symbols: # Address Size File Name 0x100005B00 0x000000EC [ 2] -[MXRSnapLearnInviteView drawRect:] 0x100005BEC 0x0000024C [ 2] -[MXRSnapLearnInviteView generatorlogoImageQRCode] 0x100005E38 0x0000005C [ 2] _CGRectMake 0x100005E94 0x00000034 [ 2] -[MXRSnapLearnInviteView inviteCode] 0x100005EC8 0x00000050 [ 2] -[MXRSnapLearnInviteView setInviteCode:] 0x100005F18 0x0000003C [ 2] -[MXRSnapLearnInviteView .cxx_destruct] 0x100005F54 0x000001D8 [ 3] -[MXRPKHomeCellViewModel initWithModel:] 0x10000612C 0x0000016C [ 3] -[MXRPKHomeCellViewModel encodeWithCoder:] 0x100006298 0x00000268 [ 3] -[MXRPKHomeCellViewModel initWithCoder:] 0x100006500 0x00000040 [ 3] -[MXRPKHomeCellViewModel desc] 0x100006540 0x00000044 [ 3] -[MXRPKHomeCellViewModel setDesc:] 0x100006584 0x00000040 [ 3] -[MXRPKHomeCellViewModel name] 0x1000065C4 0x00000044 [ 3] -[MXRPKHomeCellViewModel setName:] 0x100006608 0x00000040 [ 3] -[MXRPKHomeCellViewModel pic] 0x100006648 0x00000044 [ 3] -[MXRPKHomeCellViewModel setPic:] 0x10000668C 0x00000040 [ 3] -[MXRPKHomeCellViewModel classifyId] 0x1000066CC 0x00000044 [ 3] -[MXRPKHomeCellViewModel setClassifyId:] 0x100006710 0x000000B8 [ 3] -[MXRPKHomeCellViewModel .cxx_destruct] ... 0x1060C82D0 0x000000C0 [3391] _jerrenv 0x1060C8390 0x000204E0 [4793] _GC_arrays 0x1060E8870 0x00000100 [4793] _GC_bm_table 0x1060E8970 0x00000008 [4793] _GC_noop_sink
同样首列是数据在文件的偏移地址，第二列是占用大小，第三列是所属文件序号，对应上述Object files列表，最后是名字。
4、已废弃&多余重复的字段
# Dead Stripped Symbols: # Size File Name <<dead>> 0x00000001 [ 1] literal string: <<dead>> 0x00000005 [ 3] literal string: desc <<dead>> 0x00000005 [ 3] literal string: name <<dead>> 0x00000004 [ 3] literal string: pic <<dead>> 0x0000000B [ 3] literal string: classifyId <<dead>> 0x0000000E [ 3] literal string: .cxx_destruct <<dead>> 0x0000000B [ 3] literal string: v24@0:8@16 <<dead>> 0x00000008 [ 3] literal string: v16@0:8 <<dead>> 0x00000008 [ 3] literal string: @16@0:8 <<dead>> 0x00000001 [ 4] literal string: <<dead>> 0x00000007 [ 4] literal string: System <<dead>> 0x0000000C [ 4] literal string: UnityEngine <<dead>> 0x0000000A [ 4] literal string: System.IO <<dead>> 0x00000008 [ 5] 8-byte-literal <<dead>> 0x0000000C [ 5] literal string: PRIMARY KEY <<dead>> 0x0000000C [ 5] literal string: FOREIGN KEY <<dead>> 0x00000001 [ 5] literal string: <<dead>> 0x00000020 [ 5] CFString <<dead>> 0x00000020 [ 5] CFString <<dead>> 0x00000008 [ 5] _LKSQL_Type_Text <<dead>> 0x00000008 [ 5] _LKSQL_Type_Int <<dead>> 0x00000008 [ 5] _LKSQL_Type_Double <<dead>> 0x00000008 [ 5] _LKSQL_Type_Blob <<dead>> 0x00000008 [ 5] _LKSQL_Attribute_NotNull <<dead>> 0x00000008 [ 5] _LKSQL_Attribute_PrimaryKey <<dead>> 0x00000008 [ 5] _LKSQL_Attribute_Default <<dead>> 0x00000008 [ 5] _LKSQL_Attribute_Unique <<dead>> 0x00000008 [ 5] _LKSQL_Attribute_Check <<dead>> 0x00000008 [ 5] _LKSQL_Attribute_ForeignKey <<dead>> 0x00000008 [ 5] _LKSQL_Convert_FloatType <<dead>> 0x00000008 [ 5] _LKSQL_Convert_IntType <<dead>> 0x00000008 [ 5] _LKSQL_Convert_BlobType <<dead>> 0x00000008 [ 5] _LKSQL_Mapping_Inherit <<dead>> 0x00000008 [ 5] _LKSQL_Mapping_Binding <<dead>> 0x00000008 [ 5] _LKSQL_Mapping_UserCalculate <<dead>> 0x00000008 [ 5] _LKDB_TypeKey <<dead>> 0x00000008 [ 5] _LKDB_TypeKey_Model <<dead>> 0x00000008 [ 5] _LKDB_TypeKey_JSON <<dead>> 0x00000008 [ 5] _LKDB_TypeKey_Combo ... <<dead>> 0x00000004 [4311] 4-byte-literal <<dead>> 0x00000004 [4311] 4-byte-literal <<dead>> 0x00000004 [4311] 4-byte-literal <<dead>> 0x00000004 [4311] 4-byte-literal <<dead>> 0x00000008 [4311] 8-byte-literal <<dead>> 0x00000008 [4312] 8-byte-literal <<dead>> 0x00000014 [4320] __ZN15PxcConvexMeshHLC2EP17PxConvexMeshData_ <<dead>> 0x00000004 [4320] 4-byte-literal <<dead>> 0x00000004 [4320] 4-byte-literal <<dead>> 0x00000004 [4319] 4-byte-literal <<dead>> 0x00000076 [4319] literal string: /Applications/buildAgent/work/3d1e9e6e6eefaa7f/SDKs/compiler/iphone/../../../LowLevel/common/include/utils/PxcArray.h
参考 ： http://blog.csdn.net/wm9028/article/details/50462320
