根据NDK文档，armeabi-v7a-hard ABI应该与armeabi-v7a相同，除了它为编译添加以下标志：
TARGET_CFLAGS += -mhard-float -D_NDK_MATH_NO_SOFTFP=1
TARGET_LDFLAGS += -Wl,--no-warn-mismatch -lm_hard
但是，我注意到以armeabi-v7a-hard模式构建的库启用了NEON并且无法在Tegra2平板电脑上运行（应用程序在加载本机库后立即收到SIGILL）：
$ arm-linux-androideabi-readelf -A libRecognizer.so
Attribute Section: aeabi
File Attributes
Tag_CPU_name: "ARM v7"
Tag_CPU_arch: v7
Tag_CPU_arch_profile: Application
Tag_ARM_ISA_use: Yes
Tag_THUMB_ISA_use: Thumb-2
Tag_FP_arch: VFPv3
Tag_Advanced_SIMD_arch: NEONv1
Tag_ABI_PCS_wchar_t: 4
Tag_ABI_FP_denormal: Needed
Tag_ABI_FP_exceptions: Needed
Tag_ABI_FP_number_model: IEEE 754
Tag_ABI_align_needed: 8-byte
Tag_ABI_enum_size: int
Tag_ABI_HardFP_use: SP and DP
Tag_ABI_optimization_goals: Aggressive Speed
Tag_CPU_unaligned_access: v6
ndk-build -n表明不应该启用NEON进行编译：
-fpic -ffunction-sections -funwind-tables -fstack-protector -no-canonical-prefixes -march=armv7-a -mfpu=vfpv3-d16 -mhard-float -D_NDK_MATH_NO_SOFTFP=1 -fno-exceptions -fno-rtti -mthumb -Os -g -DNDEBUG -fomit-frame-pointer -fno-strict-aliasing -finline-limit=64
这是预期的吗？当使用硬浮动时，GCC是否自动启用NEON？
我在armeabi-v7a模式下构建了相同的库，ndk-build -n显示了以下编译标志：
-fpic -ffunction-sections -funwind-tables -fstack-protector -no-canonical-prefixes -march=armv7-a -mfpu=vfpv3-d16 -mfloat-abi=softfp -fno-exceptions -fno-rtti -mthumb -Os -g -DNDEBUG -fomit-frame-pointer -fno-strict-aliasing -finline-limit=64
Binary然后在Tegra2平板电脑上工作，readelf输出以下内容：
$ arm-linux-androideabi-readelf -A libBlinkRecognizer.so
Attribute Section: aeabi
File Attributes
Tag_CPU_name: "ARM v7"
Tag_CPU_arch: v7
Tag_CPU_arch_profile: Application
Tag_ARM_ISA_use: Yes
Tag_THUMB_ISA_use: Thumb-2
Tag_FP_arch: VFPv3-D16
Tag_ABI_PCS_wchar_t: 4
Tag_ABI_FP_denormal: Needed
Tag_ABI_FP_exceptions: Needed
Tag_ABI_FP_number_model: IEEE 754
Tag_ABI_align_needed: 8-byte
Tag_ABI_enum_size: int
Tag_ABI_HardFP_use: SP and DP
Tag_ABI_optimization_goals: Aggressive Speed
Tag_DIV_use: Not allowed
没有NEON可以使用hardfloat ABI吗？