android编译分析之9—dumpvar.mk_dumpvar android-优快云博客

本文链接：https://blog.youkuaiyun.com/lewif/article/details/50038977

本文介绍dumpvar.mk的作用及使用方式，该Makefile用于打印特定变量的值或变量对应的绝对路径。通过不同目标调用，可方便地查看Android构建系统的内部变量。

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dumpvar.mk，顾名思义就是打印某个变量的makefile，结构比较简单。
调用时，分为两种：
如果make的目标为dumpvar-TARGET_OUT这种类型，就是打印TARGET_OUT这个变量的值；
如果make的目标为dumpvar-abs-HOST_OUT_EXECUTABLES这种类型，就是要打印HOST_OUT_EXECUTABLES的绝对路径。
所以这个makefile还是非常有用的，在envsetup.sh中自己写个函数，可以打印任何自己想打印的变量。

# 这部分只有在CALLED_FROM_SETUP为true时，才会执行。
ifeq ($(CALLED_FROM_SETUP),true)

ifneq ($(filter /%,$(HOST_OUT_EXECUTABLES)),)
ABP:=$(HOST_OUT_EXECUTABLES)
else
ABP:=$(PWD)/$(HOST_OUT_EXECUTABLES)
endif

ANDROID_BUILD_PATHS := $(ABP)
ANDROID_PREBUILTS := prebuilt/$(HOST_PREBUILT_TAG)
ANDROID_GCC_PREBUILTS := prebuilts/gcc/$(HOST_PREBUILT_TAG)

# The "dumpvar" stuff lets you say something like
#
#     CALLED_FROM_SETUP=true \
#       make -f config/envsetup.make dumpvar-TARGET_OUT
# or
#     CALLED_FROM_SETUP=true \
#       make -f config/envsetup.make dumpvar-abs-HOST_OUT_EXECUTABLES
#
# The plain (non-abs) version just dumps the value of the named variable.
# The "abs" version will treat the variable as a path, and dumps an
# absolute path to it.
# 如果make的目标为dumpvar-TARGET_OUT这种类型，就是获取TARGET_OUT这个变量的值
# dumpvar-abs-HOST_OUT_EXECUTABLES这种类型，就是要打印HOST_OUT_EXECUTABLES的绝对路径
dumpvar_goals := \
    $(strip $(patsubst dumpvar-%,%,$(filter dumpvar-%,$(MAKECMDGOALS))))
ifdef dumpvar_goals

  ifneq ($(words $(dumpvar_goals)),1)
    $(error Only one "dumpvar-" goal allowed. Saw "$(MAKECMDGOALS)")
  endif

  # If the goal is of the form "dumpvar-abs-VARNAME", then
  # treat VARNAME as a path and return the absolute path to it.
  absolute_dumpvar := $(strip $(filter abs-%,$(dumpvar_goals)))
  ifdef absolute_dumpvar
    dumpvar_goals := $(patsubst abs-%,%,$(dumpvar_goals))
    ifneq ($(filter /%,$($(dumpvar_goals))),)
      DUMPVAR_VALUE := $($(dumpvar_goals))
    else
      DUMPVAR_VALUE := $(PWD)/$($(dumpvar_goals))
    endif
    dumpvar_target := dumpvar-abs-$(dumpvar_goals)
  else
    DUMPVAR_VALUE := $($(dumpvar_goals))
    dumpvar_target := dumpvar-$(dumpvar_goals)
  endif

.PHONY: $(dumpvar_target)
$(dumpvar_target):
    @echo $(DUMPVAR_VALUE)

endif # dumpvar_goals

# 所有设置完成后(lunch执行完成)，会调用report_config
# 前面都是调用单个dumpvar-TARGET_OUT,获取单个变量的值
ifneq ($(dumpvar_goals),report_config)
PRINT_BUILD_CONFIG:=
endif

endif # CALLED_FROM_SETUP

如果PRINT_BUILD_CONFIG非空，就会调用info打印系统中这些变量的值。通常lunch结束时会打印这些信息。

ifneq ($(PRINT_BUILD_CONFIG),)
HOST_OS_EXTRA:=$(shell python -c "import platform; print(platform.platform())")
$(info ============================================)
$(info   PLATFORM_VERSION_CODENAME=$(PLATFORM_VERSION_CODENAME))
$(info   PLATFORM_VERSION=$(PLATFORM_VERSION))
$(info   TARGET_PRODUCT=$(TARGET_PRODUCT))
$(info   TARGET_BUILD_VARIANT=$(TARGET_BUILD_VARIANT))
$(info   TARGET_BUILD_TYPE=$(TARGET_BUILD_TYPE))
$(info   TARGET_BUILD_APPS=$(TARGET_BUILD_APPS))
$(info   TARGET_ARCH=$(TARGET_ARCH))
$(info   TARGET_ARCH_VARIANT=$(TARGET_ARCH_VARIANT))
$(info   TARGET_CPU_VARIANT=$(TARGET_CPU_VARIANT))
$(info   TARGET_2ND_ARCH=$(TARGET_2ND_ARCH))
$(info   TARGET_2ND_ARCH_VARIANT=$(TARGET_2ND_ARCH_VARIANT))
$(info   TARGET_2ND_CPU_VARIANT=$(TARGET_2ND_CPU_VARIANT))
$(info   HOST_ARCH=$(HOST_ARCH))
$(info   HOST_OS=$(HOST_OS))
$(info   HOST_OS_EXTRA=$(HOST_OS_EXTRA))
$(info   HOST_BUILD_TYPE=$(HOST_BUILD_TYPE))
$(info   BUILD_ID=$(BUILD_ID))
$(info   OUT_DIR=$(OUT_DIR))
$(info ============================================)
endif