Questions about variants in build.ninja?

[Chen Wang]

Hello,

I'm a new people to build aosp. After I input "mmm bionic/:libc", I checked the file "soong/build.ninja" and see multiple sections about libc. There are comments sections as below:

# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #

# Module:  libc

# Variant: android_x86_core_shared

# Type:    cc_library

# Factory: android/soong/android.ModuleFactoryAdaptor.func1

# Defined: bionic/libc/Android.bp:1528:1

I see they have same Module/Type/Factory/Defined, but different  Variant. I list them as below:

android_x86_core_shared

android_x86_core_shared_10000

android_x86_core_shared_10000_apex_test_build_features

android_x86_core_shared_10000_com.android.conscrypt

......

android_x86_core_static

android_x86_core_static_10000

android_x86_core_static_10000_apex_test_build_features

android_x86_core_static_10000_com.android.conscrypt

......

android_x86_recovery_shared

android_x86_recovery_static

Can somebody tell me how they are created?  

Also I checked output, there are some folders named "android_x86_core_static" and "android_x86_core_shared_10000", looks has something with upon variants, right? 

Thanks in adv.