From 6371da10f85471d9530e53367027078d305fe832 Mon Sep 17 00:00:00 2001 From: David 'Digit' Turner Date: Tue, 13 Dec 2011 17:21:56 +0100 Subject: [PATCH] x86: Refine the way we configure the x86 build. This is the result of a recent conversation around the x86 ABI and its relationship with how we build platform images. Briefly: - We want to use feature-based macros like ARCH_X86_HAVE_$FEATURE instead of relying on explicit compiler macros like -DUSE_$FEATURE - We want to allow for other x86-based arch variants, e.g. if someone wants to build Android for a CPU that doesn't support the NDK x86 ABI. However, we need to ensure these are not tagged compatible by mistake (see check at the end of TARGET_linux-x86.mk) - There are several flags which use is dubious now that we have a dedicated toolchain to build all the x86 stuff. Comment them as 'to be considered for removal'. We'll do the proper checks later. Change-Id: I7768d7c34d73e274cbf4c09ae831b55280d6bb58 --- core/combo/TARGET_linux-x86.mk | 90 +++++++++++++++++++++++---------- core/combo/arch/x86/x86-atom.mk | 18 +++++++ core/combo/arch/x86/x86.mk | 35 +++++++++++++ 3 files changed, 115 insertions(+), 28 deletions(-) create mode 100644 core/combo/arch/x86/x86-atom.mk create mode 100644 core/combo/arch/x86/x86.mk diff --git a/core/combo/TARGET_linux-x86.mk b/core/combo/TARGET_linux-x86.mk index ed3ae082c..6efc6a437 100644 --- a/core/combo/TARGET_linux-x86.mk +++ b/core/combo/TARGET_linux-x86.mk @@ -22,6 +22,18 @@ ifeq ($(strip $(TARGET_ARCH_VARIANT)),) TARGET_ARCH_VARIANT := x86 endif +# Include the arch-variant-specific configuration file. +# Its role is to define various ARCH_X86_HAVE_XXX feature macros, +# plus initial values for TARGET_GLOBAL_CFLAGS +# +TARGET_ARCH_SPECIFIC_MAKEFILE := $(BUILD_COMBOS)/arch/$(TARGET_ARCH)/$(TARGET_ARCH_VARIANT).mk +ifeq ($(strip $(wildcard $(TARGET_ARCH_SPECIFIC_MAKEFILE))),) +$(error Unknown $(TARGET_ARCH) architecture version: $(TARGET_ARCH_VARIANT)) +endif + +include $(TARGET_ARCH_SPECIFIC_MAKEFILE) + + # You can set TARGET_TOOLS_PREFIX to get gcc from somewhere else ifeq ($(strip $(TARGET_TOOLS_PREFIX)),) TARGET_TOOLS_PREFIX := \ @@ -84,44 +96,48 @@ TARGET_GLOBAL_CFLAGS += \ -funwind-tables \ -include $(call select-android-config-h,target_linux-x86) -# Needs to be fixed later -#TARGET_GLOBAL_CFLAGS += \ -# -fstack-protector - -# Needs to be added for RELEASE -#TARGET_GLOBAL_CFLAGS += \ -# -DNDEBUG - +# XXX: Not sure this is still needed. Must check with our toolchains. TARGET_GLOBAL_CPPFLAGS += \ -fno-use-cxa-atexit -ifeq ($(TARGET_ARCH_VARIANT),x86-atom) - # Basic ATOM flags. - TARGET_GLOBAL_CFLAGS += -march=atom -mstackrealign -mfpmath=sse +# XXX: Our toolchain is normally configured to always set these flags by default +# however, there have been reports that this is sometimes not the case. So make +# them explicit here unless we have the time to carefully check it +# +TARGET_GLOBAL_CFLAGS += -mstackrealign -msse3 -mfpmath=sse - # There are various levels of ATOM processors out there. Different ones have different - # capabilities. This first define matches the NDK's minimum ABI requirements. - # Note: Not all of the flags set here are actually used in Android. They are provided - # to allow for the addition of corresponding optimizations. - TARGET_GLOBAL_CFLAGS += -DUSE_MMX -DUSE_SSE -DUSE_SSE2 -DUSE_SSE3 - - # If you wish to build a BSP that will only be used on hardware that has additional - # available instructions, enable them here. By default, this is commented off so that - # the default images can run on all processors that are NDK ABI compliant. - # TARGET_GLOBAL_CFLAGS += -DUSE_SSSE3 -else - # Plain 'x86' - lowest common denominator. This should run pretty much on any hardware. - # - # Note: The NDK's ABI (see the NDK ABI documentation) requires many of the more recent - # instruction set additions. You can build an "x86" BSP that will run on very old hardware, - # but it won't be able to run much of the x86 NDK compliant code. - TARGET_GLOBAL_CFLAGS += -march=i686 +# XXX: These flags should not be defined here anymore. Instead, the Android.mk +# of the modules that depend on these features should instead check the +# corresponding macros (e.g. ARCH_X86_HAVE_SSE2 and ARCH_X86_HAVE_SSSE3) +# Keep them here until this is all cleared up. +# +ifeq ($(ARCH_X86_HAVE_SSE2),true) +TARGET_GLOBAL_CFLAGS += -DUSE_SSE2 endif +ifeq ($(ARCH_X86_HAVE_SSSE3),true) # yes, really SSSE3, not SSE3! +TARGET_GLOBAL_CFLAGS += -DUSE_SSSE3 +endif + +# XXX: This flag is probably redundant. I believe our toolchain always sets +# it by default. Consider for removal. +# TARGET_GLOBAL_CFLAGS += -mbionic + +# XXX: This flag is probably redundant. The macro should be defined by our +# toolchain binaries automatically (as a compiler built-in). +# Check with: $BINPREFIX-gcc -dM -E < /dev/null +# +# Consider for removal. +# TARGET_GLOBAL_CFLAGS += -D__ANDROID__ +# XXX: This flag is probably redundant since our toolchain binaries already +# generate 32-bit machine code. It probably dates back to the old days +# where we were using the host toolchain on Linux to build the platform +# images. Consider it for removal. TARGET_GLOBAL_LDFLAGS += -m32 + TARGET_GLOBAL_LDFLAGS += -Wl,-z,noexecstack TARGET_GLOBAL_LDFLAGS += -Wl,--gc-sections @@ -205,3 +221,21 @@ $(hide) $(PRIVATE_CXX) \ -Wl,--end-group \ $(if $(filter true,$(PRIVATE_NO_CRT)),,$(TARGET_CRTEND_O)) endef + +# Special check for x86 NDK ABI compatibility. +# The TARGET_CPU_ABI variable should be defined in BoardConfig.mk to 'x86' +# *only* if the platform image is compatible with the NDK x86 ABI. +# +# We perform a small check here to ensure that nothing bad can happen. +# +ifeq ($(TARGET_CPU_ABI),x86) + ifneq (true-true-true-true,$(ARCH_X86_HAVE_MMX)-$(ARCH_X86_HAVE_SSE)-$(ARCH_X86_HAVE_SSE2)-$(ARCH_X86_HAVE_SSE3)) + $(info ERROR: Your x86 platform image is not compatible with the NDK x86 ABI) + $(info As such, you should *not* define TARGET_CPU_ABI to 'x86' in your BoardConfig.mk) + $(info to ensure that your device will not be mistakenly listed as compatible by + $(info the Android Market. Also, it is likely that the image will fail the CTS tests) + $(info Please undefine TARGET_CPU_ABI in your BoardConfig.mk, or select the value 'none') + $(info The corresponding image will still be able to run Dalvik-based Android applications) + $(error Aborting build! Please fix your BoardConfig.mk) + endif +endif diff --git a/core/combo/arch/x86/x86-atom.mk b/core/combo/arch/x86/x86-atom.mk new file mode 100644 index 000000000..85998e7d5 --- /dev/null +++ b/core/combo/arch/x86/x86-atom.mk @@ -0,0 +1,18 @@ +# This file contains feature macro definitions specific to the +# 'x86-atom' arch variant. This is an extension of the 'x86' base variant +# that adds Atom-specific features. +# +# See build/core/combo/arch/x86/x86.mk for differences. +# +ARCH_X86_HAVE_MMX := true +ARCH_X86_HAVE_SSE := true +ARCH_X86_HAVE_SSE2 := true +ARCH_X86_HAVE_SSE3 := true + +ARCH_X86_HAVE_SSSE3 := true +ARCH_X86_HAVE_MOVBE := true +ARCH_X86_HAVE_POPCNT := false # popcnt is not supported by current Atom CPUs + +# This flag is used to enabled Atom-specific optimizations with our toolchain +# +TARGET_GLOBAL_CFLAGS += -march=atom diff --git a/core/combo/arch/x86/x86.mk b/core/combo/arch/x86/x86.mk new file mode 100644 index 000000000..476da452b --- /dev/null +++ b/core/combo/arch/x86/x86.mk @@ -0,0 +1,35 @@ +# This file contains feature macro definitions specific to the +# base 'x86' platform ABI. This one must *strictly* match the NDK x86 ABI +# which mandates specific CPU extensions to be available. +# +# It is also used to build full_x86-eng / sdk_x86-eng platform images that +# are run in the emulator under KVM emulation (i.e. running directly on +# the host development machine's CPU). +# + +# If your target device doesn't support the four following features, then +# it cannot be compatible with the NDK x86 ABI. You should define a new +# target arch variant (e.g. "x86-mydevice") and a corresponding file +# under build/core/combo/arch/x86/ +# +ARCH_X86_HAVE_MMX := true +ARCH_X86_HAVE_SSE := true +ARCH_X86_HAVE_SSE2 := true +ARCH_X86_HAVE_SSE3 := true + +# These features are optional and shall not be included in the base platform +# Otherwise, they sdk_x86-eng system images might fail to run on some +# developer machines. +# + +ARCH_X86_HAVE_SSSE3 := false +ARCH_X86_HAVE_MOVBE := false +ARCH_X86_HAVE_POPCNT := false + + +# XXX: This flag is probably redundant, because it should be set by default +# by our toolchain binaries. However, there have been reports that this may +# not always work as intended, so keep it unless we have the time to check +# everything properly. + +TARGET_GLOBAL_CFLAGS += -march=i686