mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-09-29 10:52:09 +00:00
a55014d09b
LTO (Link-Time Optimisation) is an very useful feature which can significantly reduce the size of U-Boot binaries. So far it has been made available for selected ARM boards and sandbox. However, incremental builds are much slower when LTO is used. For example, an incremental build of sandbox takes 2.1 seconds on my machine, but 6.7 seconds with LTO enabled. Add a NO_LTO parameter to the build, similar to NO_SDL, so it can be disabled during development if needed, for faster builds. Add some documentation about LTO while we are here. Signed-off-by: Simon Glass <sjg@chromium.org>
183 lines
5 KiB
Makefile
183 lines
5 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0+
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#
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# (C) Copyright 2000-2002
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# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
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ifndef CONFIG_STANDALONE_LOAD_ADDR
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ifneq ($(CONFIG_ARCH_OMAP2PLUS),)
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CONFIG_STANDALONE_LOAD_ADDR = 0x80300000
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else
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CONFIG_STANDALONE_LOAD_ADDR = 0xc100000
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endif
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endif
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CFLAGS_NON_EFI := -fno-pic -ffixed-r9 -ffunction-sections -fdata-sections \
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-fstack-protector-strong
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CFLAGS_EFI := -fpic -fshort-wchar
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ifneq ($(LTO_ENABLE)$(CONFIG_USE_PRIVATE_LIBGCC),yy)
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LDFLAGS_FINAL += --gc-sections
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endif
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ifneq ($(LTO_ENABLE),y)
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PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections
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endif
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PLATFORM_RELFLAGS += -fno-common -ffixed-r9
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PLATFORM_RELFLAGS += $(call cc-option, -msoft-float) \
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$(call cc-option,-mgeneral-regs-only) \
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$(call cc-option,-mshort-load-bytes,$(call cc-option,-malignment-traps,))
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# LLVM support
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LLVM_RELFLAGS := $(call cc-option,-mllvm,) \
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$(call cc-option,-mno-movt,)
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PLATFORM_RELFLAGS += $(LLVM_RELFLAGS)
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PLATFORM_CPPFLAGS += -D__ARM__
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ifdef CONFIG_ARM64
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PLATFORM_ELFFLAGS += -B aarch64 -O elf64-littleaarch64
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else
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PLATFORM_ELFFLAGS += -B arm -O elf32-littlearm
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endif
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# Choose between ARM/Thumb instruction sets
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ifeq ($(CONFIG_$(SPL_)SYS_THUMB_BUILD),y)
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AFLAGS_IMPLICIT_IT := $(call as-option,-Wa$(comma)-mimplicit-it=always)
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PF_CPPFLAGS_ARM := $(AFLAGS_IMPLICIT_IT) \
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$(call cc-option, -mthumb -mthumb-interwork,\
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$(call cc-option,-marm,)\
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$(call cc-option,-mno-thumb-interwork,)\
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)
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else
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PF_CPPFLAGS_ARM := $(call cc-option,-marm,) \
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$(call cc-option,-mno-thumb-interwork,)
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endif
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# Only test once
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ifeq ($(CONFIG_$(SPL_)SYS_THUMB_BUILD),y)
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archprepare: checkthumb checkgcc6
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checkthumb:
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@if test "$(call cc-name)" = "gcc" -a \
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"$(call cc-version)" -lt "0404"; then \
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echo -n '*** Your GCC does not produce working '; \
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echo 'binaries in THUMB mode.'; \
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echo '*** Your board is configured for THUMB mode.'; \
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false; \
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fi
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else
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archprepare: checkgcc6
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endif
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checkgcc6:
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@if test "$(call cc-name)" = "gcc" -a \
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"$(call cc-version)" -lt "0600"; then \
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echo '*** Your GCC is older than 6.0 and is not supported'; \
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false; \
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fi
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# Try if EABI is supported, else fall back to old API,
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# i. e. for example:
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# - with ELDK 4.2 (EABI supported), use:
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# -mabi=aapcs-linux
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# - with ELDK 4.1 (gcc 4.x, no EABI), use:
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# -mabi=apcs-gnu
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# - with ELDK 3.1 (gcc 3.x), use:
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# -mapcs-32
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PF_CPPFLAGS_ABI := $(call cc-option,\
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-mabi=aapcs-linux,\
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$(call cc-option,\
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-mapcs-32,\
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$(call cc-option,\
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-mabi=apcs-gnu,\
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)\
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)\
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)
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PLATFORM_CPPFLAGS += $(PF_CPPFLAGS_ARM) $(PF_CPPFLAGS_ABI)
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# For EABI, make sure to provide raise()
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ifneq (,$(findstring -mabi=aapcs-linux,$(PLATFORM_CPPFLAGS)))
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# This file is parsed many times, so the string may get added multiple
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# times. Also, the prefix needs to be different based on whether
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# CONFIG_SPL_BUILD is defined or not. 'filter-out' the existing entry
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# before adding the correct one.
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PLATFORM_LIBS := arch/arm/lib/eabi_compat.o \
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$(filter-out arch/arm/lib/eabi_compat.o, $(PLATFORM_LIBS))
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endif
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# needed for relocation
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LDFLAGS_u-boot += -pie
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#
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# FIXME: binutils versions < 2.22 have a bug in the assembler where
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# branches to weak symbols can be incorrectly optimized in thumb mode
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# to a short branch (b.n instruction) that won't reach when the symbol
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# gets preempted
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#
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# http://sourceware.org/bugzilla/show_bug.cgi?id=12532
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#
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ifeq ($(CONFIG_$(SPL_)SYS_THUMB_BUILD),y)
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ifeq ($(GAS_BUG_12532),)
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export GAS_BUG_12532:=$(shell if [ $(call binutils-version) -lt 0222 ] ; \
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then echo y; else echo n; fi)
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endif
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ifeq ($(GAS_BUG_12532),y)
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PLATFORM_RELFLAGS += -fno-optimize-sibling-calls
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endif
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endif
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ifneq ($(CONFIG_SPL_BUILD),y)
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# Check that only R_ARM_RELATIVE relocations are generated.
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INPUTS-y += checkarmreloc
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# The movt / movw can hardcode 16 bit parts of the addresses in the
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# instruction. Relocation is not supported for that case, so disable
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# such usage by requiring word relocations.
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PLATFORM_CPPFLAGS += $(call cc-option, -mword-relocations)
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PLATFORM_CPPFLAGS += $(call cc-option, -fno-pic)
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endif
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# limit ourselves to the sections we want in the .bin.
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ifdef CONFIG_ARM64
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OBJCOPYFLAGS += -j .text -j .secure_text -j .secure_data -j .rodata -j .data \
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-j __u_boot_list -j .rela.dyn -j .got -j .got.plt \
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-j .binman_sym_table -j .text_rest
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else
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OBJCOPYFLAGS += -j .text -j .secure_text -j .secure_data -j .rodata -j .hash \
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-j .data -j .got -j .got.plt -j __u_boot_list -j .rel.dyn \
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-j .binman_sym_table -j .text_rest
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endif
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# if a dtb section exists we always have to include it
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# there are only two cases where it is generated
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# 1) OF_EMBEDED is turned on
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# 2) unit tests include device tree blobs
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OBJCOPYFLAGS += -j .dtb.init.rodata
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ifdef CONFIG_EFI_LOADER
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OBJCOPYFLAGS += -j .efi_runtime -j .efi_runtime_rel
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endif
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ifdef CONFIG_MACH_IMX
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ifneq ($(CONFIG_IMX_CONFIG),"")
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ifdef CONFIG_SPL
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ifndef CONFIG_SPL_BUILD
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INPUTS-y += SPL
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endif
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else
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ifeq ($(CONFIG_OF_SEPARATE),y)
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INPUTS-y += u-boot-dtb.imx
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else
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INPUTS-y += u-boot.imx
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endif
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endif
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ifneq ($(CONFIG_VF610),)
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INPUTS-y += u-boot.vyb
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endif
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endif
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endif
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EFI_LDS := elf_arm_efi.lds
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EFI_CRT0 := crt0_arm_efi.o
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EFI_RELOC := reloc_arm_efi.o
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