OpenWRT构建系统中的Makefile问题

以下代码取自OpenWRT项目。有人可以给出一个抽象描述吗？提前致谢！OpenWRT构建系统中的Makefile问题

# 
# Copyright (C) 2007 OpenWrt.org 
# 
# This is free software, licensed under the GNU General Public License v2. 
# See /LICENSE for more information. 
# 

SUBTARGETS:=clean download prepare compile install update refresh prereq dist distcheck 

subtarget-default = $(filter-out ., \ 
    $(if $($(1)/builddirs-$(2)),$($(1)/builddirs-$(2)), \ 
    $(if $($(1)/builddirs-default),$($(1)/builddirs-default), \ 
    $($(1)/builddirs)))) 

define subtarget 
    $(call warn_eval,$(1),t,T,$(1)/$(2): $($(1)/) $(foreach bd,$(call subtarget-default,$(1),$(2)),$(1)/$(bd)/$(2))) 

endef 


lastdir=$(word $(words $(subst /, ,$(1))),$(subst /, ,$(1))) 
diralias=$(if $(findstring $(1),$(call lastdir,$(1))),,$(call lastdir,$(1))) 

# Parameters: <subdir> 
define subdir 
    $(call warn,$(1),d,D $(1)) 
    $(foreach bd,$($(1)/builddirs), 
    $(call warn,$(1),d,BD $(1)/$(bd)) 
    $(foreach target,$(SUBTARGETS), 
     $(foreach btype,$(buildtypes-$(bd)), 
     $(call warn_eval,$(1)/$(bd),t,T,$(1)/$(bd)/$(btype)/$(target): $(if $(QUILT),,$($(1)/$(bd)/$(btype)/$(target)) $(call $(1)//$(btype)/$(target),$(1)/$(bd)/$(btype)))) 
      +$$(SUBMAKE) -C $(1)/$(bd) $(btype)-$(target) $(if $(findstring $(bd),$($(1)/builddirs-ignore-$(btype)-$(target))), || $(call MESSAGE, ERROR: $(1)/$(bd) [$(btype)] failed to build.)) 
     $$(if $(call debug,$(1)/$(bd),v),,.SILENT: $(1)/$(bd)/$(btype)/$(target)) 
     $(if $(call diralias,$(bd)),$(call warn_eval,$(1)/$(bd),l,T,$(1)/$(call diralias,$(bd))/$(btype)/$(target): $(1)/$(bd)/$(btype)/$(target))) 
    ) 
     $(call warn_eval,$(1)/$(bd),t,T,$(1)/$(bd)/$(target): $(if $(QUILT),,$($(1)/$(bd)/$(target)) $(call $(1)//$(target),$(1)/$(bd)))) 
     $(if $(BUILD_LOG),@mkdir -p $(BUILD_LOG_DIR)/$(1)/$(bd)) 
     $(foreach variant,$(if $(BUILD_VARIANT),$(BUILD_VARIANT),$(if $($(1)/$(bd)/variants),$($(1)/$(bd)/variants),__default)), 
      +$(if $(BUILD_LOG),set -o pipefail;) $$(SUBMAKE) -C $(1)/$(bd) $(target) BUILD_VARIANT="$(filter-out __default,$(variant))" $(if $(BUILD_LOG),SILENT= 2>&1 | tee $(BUILD_LOG_DIR)/$(1)/$(bd)/$(target).txt) $(if $(findstring $(bd),$($(1)/builddirs-ignore-$(target))), || $(call MESSAGE, ERROR: $(1)/$(bd) failed to build$(if $(filter-out __default,$(variant)), (build variant: $(variant))).)) 
     ) 
     $$(if $(call debug,$(1)/$(bd),v),,.SILENT: $(1)/$(bd)/$(target)) 

     # legacy targets 
     $(call warn_eval,$(1)/$(bd),l,T,$(1)/$(bd)-$(target): $(1)/$(bd)/$(target)) 
     # aliases 
     $(if $(call diralias,$(bd)),$(call warn_eval,$(1)/$(bd),l,T,$(1)/$(call diralias,$(bd))/$(target): $(1)/$(bd)/$(target))) 
    ) 
) 
    $(foreach target,$(SUBTARGETS),$(call subtarget,$(1),$(target))) 
endef 

# Parameters: <subdir> <name> <target> <depends> <config options> <stampfile location> 
define stampfile 
    $(1)/stamp-$(3):=$(if $(6),$(6),$(STAGING_DIR))/stamp/.$(2)_$(3)$(if $(5),_$(call confvar,$(5))) 
    $$($(1)/stamp-$(3)): $(TMP_DIR)/.build $(4) 
    @+$(SCRIPT_DIR)/timestamp.pl -n $$($(1)/stamp-$(3)) $(1) $(4) || \ 
     $(MAKE) $$($(1)/flags-$(3)) $(1)/$(3) 
    @mkdir -p $$$$(dirname $$($(1)/stamp-$(3))) 
    @touch $$($(1)/stamp-$(3)) 

    $$(if $(call debug,$(1),v),,.SILENT: $$($(1)/stamp-$(3))) 

    .PRECIOUS: $$($(1)/stamp-$(3)) # work around a make bug 

    $(1)//clean:=$(1)/stamp-$(3)/clean 
    $(1)/stamp-$(3)/clean: FORCE 
    @rm -f $$($(1)/stamp-$(3)) 

endef

来源

2010-01-03 Dever Chang

我已经爱上谁写的 – 2010-01-03 15:38:57

是的，他们使用的makefile灵活的家伙。就像一个函数式编程语言。进行字符串替换，然后将结果作为makefile目标的一部分进行评估。好想法。我也喜欢这个。 – 2010-01-08 08:08:17

它以目录名称作为第一参数被调用，例如， in package/Makefile它是'包' 然后它将变量package/builddirs视为包含在SUBTARGETS变量中的有效构建目标的子目录列表。

为了运行包'foo'的'编译'目标，它允许您运行'make package/foo/compile'，它将递归地调用具有正确环境变量的make来构建子目录。

此模板还支持一些可通过环境变量启用的可选功能，例如，用于将输出记录到文件，忽略依赖关系等。它还支持选择性调试输出。

的stampfile模板就是加快小的makefile目标的包装通过保持一个递归时间戳的检查stampfile建立在其周围

来源

2010-01-03 15:53:58 nbd

感谢您的评论，这让我很困惑:) – 2010-01-08 08:09:54

OpenWRT构建系统中的Makefile问题

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