makefile 内循环的问题

Question

我正在尝试实现在 makefile 中显示构建进度的逻辑。

我可以成功地在级联的 makefile 中为目标“simple”打印它。然而，当涉及到 makefile 中的另一个目标“for”时，出现了问题，我无法弄清楚它是什么。

任何帮助将不胜感激。

## BUILD is initially undefined
ifndef BUILD
# T estimates how many targets we are building by replacing BUILD with a special string
T := $(shell $(MAKE) progress --no-print-directory \
      -nrRf $(firstword $(MAKEFILE_LIST)) \
      BUILD="COUNTTHIS" | grep -c "COUNTTHIS")
## N is the target number
N := x
## incrementing counter
C = $(words $N)$(eval N := x $N)$(shell export $N)
## BUILD is now defined to show the progress, this also avoids redefining T in loop
BUILD = echo "`expr "   [\`expr $C '*' 100 / $T\`" : '.*\(....\)$$'`%]"
endif

MODULE_LIST  = module1
MODULE_LIST := $(MODULE_LIST) module2
MODULE_LIST := $(MODULE_LIST) module3
MODULE_LIST := $(MODULE_LIST) module4
MODULE_LIST := $(MODULE_LIST) module5

progress:
    @$(BUILD)
    @$(BUILD)
    @$(BUILD)
    @$(BUILD)
    @$(BUILD)

simple:
    # T=5 and C increases for every access
    @$(BUILD) "Cleaning Module \"module1\""
    @sleep 0.1
    @$(BUILD) "Cleaning Module \"module2\""
    @sleep 0.1
    @$(BUILD) "Cleaning Module \"module3\""
    @sleep 0.1
    @$(BUILD) "Cleaning Module \"module4\""
    @sleep 0.1
    @$(BUILD) "Cleaning Module \"module5\""
    @sleep 0.1

for:
    # T=1 and C increases for every access but not inside the for loop
    @for MODULE in $(MODULE_LIST); do \
        $(BUILD) "Cleaning Module \"$$MODULE\"" ; \
        sleep 0.1 ; \
    done

Answer 1

正如您在评论中指出的那样，问题在于 for 循环在 shell 内部执行，因此不会更新 Makefile 的变量（或者至少在 Make 通过评估其中的变量引用来构建命令字符串时不会更新一次） 。

我能看到的唯一可行的解​​决方案是将循环结构移至 Makefile 中。尝试一下：

## PRINT_PROGRESS is initially undefined
ifndef PRINT_PROGRESS
# T estimates how many targets we are building by replacing PRINT_PROGRESS with a special string
T := $(shell $(MAKE) $(MAKECMDGOALS) --no-print-directory \
      -rRf $(firstword $(MAKEFILE_LIST)) \
      PRINT_PROGRESS="echo COUNTTHIS" BUILD="test x ||" | grep -c "COUNTTHIS")
N := 1
## PRINT_PROGRESS is now defined to show the progress and update N
PRINT_PROGRESS = echo "`expr "   [\`expr $N '*' 100 / $T\`" : '.*\(....\)$'`%]"$(eval N := $(shell expr $N + 1))
endif
ifndef BUILD
BUILD := #blank
endif

MODULE_LIST  = module1
MODULE_LIST += module2
MODULE_LIST += module3
MODULE_LIST += module4
MODULE_LIST += module5

simple:
    # T=5 and C increases for every access
    @$(PRINT_PROGRESS) "Cleaning Module \"module1\""
    @$(BUILD) { sleep 0.1 ; echo "doing some work" ; }
    @$(PRINT_PROGRESS) "Cleaning Module \"module2\""
    @$(BUILD) { sleep 0.1 ; echo "doing some work" ; }
    @$(PRINT_PROGRESS) "Cleaning Module \"module3\""
    @$(BUILD) { sleep 0.1 ; echo "doing some work" ; }
    @$(PRINT_PROGRESS) "Cleaning Module \"module4\""
    @$(BUILD) { sleep 0.1 ; echo "doing some work" ; }
    @$(PRINT_PROGRESS) "Cleaning Module \"module5\""
    @$(BUILD) { sleep 0.1 ; echo "doing some work" ; }

for:
    @$(foreach MODULE,$(MODULE_LIST),\
        $(PRINT_PROGRESS) "Cleaning Module \"$(MODULE)\"" ; \
        $(BUILD) { \
            sleep 0.1 ; \
            echo "doing some work" ; \
        } ; \
    )

这还包括一些其他更改。

乍一看似乎合理的解决方案是从 makefile 中导出 N 并设计 PRINT_PROGRESS 命令，以便 N 始终作为环境进行更新多变的。不过，我找不到一种方法来完成这项工作，因为它需要某种方式将更新 N值返回放入之后命令已被写入，因此单独的命令仍然有效。

---

编辑：运行上面的确切脚本时的输出（带有更正的制表符缩进）以及使用的版本：

jpab@oberon : /memtmp
$ make --version
GNU Make 3.81
Copyright (C) 2006  Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.

This program built for x86_64-pc-linux-gnu

jpab@oberon : /memtmp
$ bash --version
GNU bash, version 4.1.5(1)-release (x86_64-pc-linux-gnu)
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

jpab@oberon : /memtmp
$ make
# T=5 and C increases for every access
 [20%] Cleaning Module "module1"
doing some work
 [40%] Cleaning Module "module2"
doing some work
 [60%] Cleaning Module "module3"
doing some work
 [80%] Cleaning Module "module4"
doing some work
[100%] Cleaning Module "module5"
doing some work

jpab@oberon : /memtmp
$ make for
 [20%] Cleaning Module "module1"
doing some work
 [40%] Cleaning Module "module2"
doing some work
 [60%] Cleaning Module "module3"
doing some work
 [80%] Cleaning Module "module4"
doing some work
[100%] Cleaning Module "module5"
doing some work