目前iOS的指令集有以下幾種：
armv6
iPhone
iPhone2
iPhone3G
第一代和第二代iPod Touch
armv7
iPhone4
iPhone4S
armv7s
iPhone5
iPhone5C
arm64
iPhone5S
機(jī)器對(duì)指令集的支持是向下兼容的，因此armv7的指令集是可以運(yùn)行在iphone5S的，只是效率沒那么高而已~
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Architecture ：?指你想支持的指令集涕癣。
Valid architectures : 指即將編譯的指令集愈诚。
Build Active Architecture Only : 只是否只編譯當(dāng)前適用的指令集。
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現(xiàn)在是2014年初包警，其實(shí)4和4S的用戶還是蠻多的，而iphone3之類的機(jī)器幾乎沒有了，所以我們的指令集最低必須基于armv7.
因此,Architecture的值選擇：armv7 armv7s arm64
PS:選arm64時(shí)需要最低支持5.1.1:
Convert Your App to a 64-Bit Binary After Updating It for iOS 7
Xcode 5.0.1 can build your app with both 32-bit and 64-bit binaries included. This combined binary requires a minimum deployment target of iOS 5.1.1 or later. The 64-bit binary runs only on 64-bit devices running iOS 7.0.3 and later. If you have an existing app, you should first update your app for iOS 7 and then port it to run on 64-bit processors. By updating it first for iOS 7, you can remove deprecated code paths and use modern practices. If you’re creating a new app, target iOS 7 and compile 32-bit and 64-bit versions of your app.
The architecture for 64-bit apps on iOS is almost identical to the architecture for OS X apps, making it easy to create a common code base that runs in both operating systems. Converting a Cocoa Touch app to 64-bit follows a similar transition process as the one for Cocoa apps on OS X. Pointers and some common C types change from 32 bits to 64 bits. Code that relies on theNSIntegerandCGFloattypes needs to be carefully examined.
Start by building the app for the 64-bit runtime, fixing any warnings that occur as well as searching your code for specific 64-bit issues. For example:
Make sure all function calls have a proper prototype.
Avoid truncating 64-bit values by accidentally assigning them to a 32-bit data type.
Ensure that calculations are performed correctly in the 64-bit version of your app.
Create data structures whose layouts are identical in the 32-bit and 64-bit versions of your app (such as when you write a data file to iCloud).
1乎澄，如果想自己的app在各個(gè)機(jī)器都能夠最高效率的運(yùn)行，則需要將Build Active Architecture Only改為NO,Valid architectures選擇對(duì)應(yīng)的指令集：armv7 armv7s arm64测摔。這個(gè)會(huì)為各個(gè)指令集編譯對(duì)應(yīng)的代碼置济，因此最后的 ipa體積基本翻了3倍,Release版本必須NO。
2避咆，如果想讓app體積保持最小舟肉，則現(xiàn)階段應(yīng)該選擇Valid architectures為armv7,這樣Build Active Architecture Only選YES或NO就無所謂了
