1LOCAL_PATH := $(call my-dir) 2 3# This is the way used to be: For ARM, ndk-build forces "softfp" 4# regardless armeabi (default to use -msoft-float) or armeabi-v7a 5# (default to use -mfpu=vfpv3-d16) 6include $(CLEAR_VARS) 7LOCAL_MODULE := float-softfp-abi 8LOCAL_SRC_FILES := test-float.c 9include $(BUILD_EXECUTABLE) 10 11 12ifeq ($(filter %armeabi-v7a,$(TARGET_ARCH_ABI)),) 13 14# 15# The following two examples are relevant only to armeabi-v7a 16# 17 18$(warning Examples hard-float-softfp-abi and hard-float-hard-abi not relevant to ABI $(TARGET_ARCH_ABI)) 19 20else 21 22ifeq (,$(filter clang%,$(NDK_TOOLCHAIN_VERSION))) 23 24# This is to compile all user code in -mhard-float (which implies 25# -mfloat-abi=hard and overrides -mfloat-abi=softfp previously added 26# by ndk-build), but still link system libm.so which use softfp. 27# All functions in Android platform headers taking or returning float/double 28# has __attribute__((pcs("aapcs"))), so even under the implied -mfloat-abi=hard 29# softfp ABI is still observed by compiler for Android native APIs. 30# 31# You also need to ensure that 32# 1. All code and library *must* be recompiled with consistent soft-abi. 33# If your project use ndk-build and import other project, you may want to do 34# 35# $NDK/ndk-build -B APP_ABI=armeabi-v7a APP_CFLAGS=-mhard-float APP_LDFLAGS=-Wl,--no-warn-mismatch 36# 37# If your project use libraries compiled by others, it's likely those were built with 38# -msoft-abi=softfp or evan -msoft-float (for armeabi). Recompile them with -mhard-float 39# 40# 2. Correct headers (eg. #include <math.h>) are always included, and there is no 41# declaration like "extern double sin(double)" w/o proper __attribute__ in 42# your code instead of including math.h, etc. See the end of sys/cdefs.h 43# the conditions upon which __NDK_FPABI__ and __NDK_FPABI_MATH__ are defined 44# 45# 3. All JNI functions should have JNICALL which is defined to __NDK_FPABI__ in jni.h. 46# 47# 4. If you use undocumented APIs which takes/returns float/double, be careful 48# to add __attribute__((pcs("aapcs"))) for arm 49# 50# Note that "--no-warn-mismatch" is needed for linker (except mclinker which check correctly) 51# to suppress linker error about not all functions use VFP register to pass argument, eg. 52# 53# .../arm-linux-androideabi/bin/ld: error: ..../test-float.o 54# uses VFP register arguments, output does not 55# 56include $(CLEAR_VARS) 57LOCAL_MODULE := hard-float-softfp-abi 58LOCAL_CFLAGS += -mhard-float 59LOCAL_SRC_FILES := test-float.c 60LOCAL_LDFLAGS := -Wl,--no-warn-mismatch 61include $(BUILD_EXECUTABLE) 62 63else 64 65# Clang before 3.4 doesn't allow change of calling convenstion for builtin, 66# and produces error message reads: 67# 68# a.i:564:6: error: function declared 'aapcs' here was previously declared without calling convention 69# int sin(double d) __attribute__((pcs("aapcs")));544 70# ^ 71# a.i:564:6: note: previous declaration is here 72# 73# As a result, "-mhard-float" doesn't work properly for now (3.3 and 3.2), unless 74# libm_hard is also used. See example below. 75# 76 77$(warning Skip example hard-float-softfp-abi for clang for now) 78 79endif # check clang 80 81# This is to compile all user code in -mhard-float and link a customized 82# libm_hard.a which follows -mfloat-abi=hard. _NDK_MATH_NO_SOFTFP=1 83# is to turn off __attribute__((pcs("aapcs"))) in math.h for all math 84# functions to accept float-abi (implicit "hard" in this case) as specified by user. 85# 86include $(CLEAR_VARS) 87LOCAL_MODULE := hard-float-hard-abi 88LOCAL_CFLAGS += -mhard-float -D_NDK_MATH_NO_SOFTFP=1 89LOCAL_LDLIBS += -lm_hard 90LOCAL_SRC_FILES := test-float.c 91LOCAL_LDFLAGS := -Wl,--no-warn-mismatch 92include $(BUILD_EXECUTABLE) 93 94endif # check armeabi-v7a 95