用作预构建命令的 CMake ninja 自定义目标会修改文件，但 ninja 在下一次构建期间会看到 depndecies 的变化答案

【问题标题】：CMake ninja custom target used as pre-build command modifies the files but ninja see the change of the depndecies during next build用作预构建命令的 CMake ninja 自定义目标会修改文件，但 ninja 在下一次构建期间会看到 depndecies 的变化
【发布时间】：2020-12-05 15:29:44
【问题描述】：

我在实际构建之前运行了一些命令

add_custom_target("${PROJECT_BUILD_NUM_FILE}" 
    COMMAND ${PROJECT_BUILD_NUM_UPDATE} "-p" "-x" -f ${PROJECT_SOURCE_DIR}/${MAIN_PATH}/${BOARD_NAME}/${PROJECT_BUILD_NUM_FILE}
    )

add_dependencies(${EXECUTABLE_NAME} "${PROJECT_BUILD_NUM_FILE}" )

当我第一次构建时（该项目是之前构建的）

>------ Build started: Project: CMakeLists, Configuration: Debug ------
  [1/1] cmd.exe /C "cd /D C:\Users\Piotr\git\gPIMS-EG\out\build\IoT-Debug && C:\Users\Piotr\git\gPIMS-EG\stm-libs\pc-exe\buildnum.exe -p -x -f C:/Users/Piotr/git/gPIMS-EG/src/EG/BuildID.h"
  Build number file used:C:/Users/Piotr/git/gPIMS-EG/src/EG/BuildID.h
  Build file updated: Build Number: 22 DateCode: 0x1d6d

Build succeeded.

BuildID.h 文件已修改并保存。修改日期设置正确。

在第二次构建时，它的行为正确

>------ Build started: Project: CMakeLists, Configuration: Debug ------
  [1/4] cmd.exe /C "cd /D C:\Users\Piotr\git\gPIMS-EG\out\build\IoT-Debug && C:\Users\Piotr\git\gPIMS-EG\stm-libs\pc-exe\buildnum.exe -p -x -f C:/Users/Piotr/git/gPIMS-EG/src/EG/BuildID.h"
  Build number file used:C:/Users/Piotr/git/gPIMS-EG/src/EG/BuildID.h
  Build file updated: Build Number: 23 DateCode: 0x1d6d
  [2/4] C:\PROGRA~2\Atollic\TRUEST~1.0\ARMTools\bin\AR097D~1.EXE -DALLOW_SOFTWARE_BKPTS=1 -DARM_MATH_CM4 -DBOOTLOADER_VERSION=1 -DCOMPILE_FOR_EG=1 -DDEBUGFILEWRITE=1 -DDEBUG_RUN_WITHOUT_CHECKS=1 -DFORCE_CUBE_USB -DHSE_VALUE=8000000UL -DSLOWSPIDEBUG=0 -DSTM32L -DSTM32L476xx -DSTM32L4xx -DUSE_EMBEDDED_PHY=1 -DUSE_FULL_ASSERT -DUSE_FULL_LL_DRIVER="" -DUSE_HAL_DRIVER -DUSE_SWOTRACE=1 -DUSE_USB_OTG_FS=1 -DUSE_USB_OTG_HS=1 -D_DEBUG=1 -D_GNU_SOURCE=1 -D__USE_SIMPLE_SWO=0 -I../../../src -I../../../src/EG -I../../../src/ZM -I../../../src/inc -I../../../stm-libs/inc -I../../../stm-libs/Drivers -I../../../stm-libs/Services -I../../../stm-libs/Services/Utils -I../../../stm-libs/RTOS/Source/include -I../../../stm-libs/RTOS/Source/portable/GCC/ARM_CM4F -I../../../stm-libs/Libraries/CMSIS/Include -I../../../stm-libs/Libraries/CMSIS/Device/ST/STM32L4xx/Include -I../../../stm-libs/Libraries/CryptoLib/Inc -I../../../stm-libs/Libraries/CryptoLib/Inc/RNG -I../../../stm-libs/drivers/USBD -I../../../stm-libs/Libraries/Middlewares/ST/STM32_USB_Device_Library/Core/Inc -I../../../stm-libs/Libraries/USB/Device/Class/CDC/Inc -I../../../stm-libs/Libraries/USB/Device/Class/MSC_HID/Inc -I../../../stm-libs/Libraries/USB/Device/Core/Inc -I../../../stm-libs/Libraries/lwip/ports/STM32F4x7 -I../../../stm-libs/Libraries/lwip/ports/STM32F4x7/arch -I../../../stm-libs/Libraries/lwip/src -I../../../stm-libs/Libraries/lwip/src/include -I../../../stm-libs/drivers/USBH -I../../../stm-libs/Libraries/USB/Host/Class/AUDIO/Inc -I../../../stm-libs/Libraries/USB/Host/Class/CDC/Inc -I../../../stm-libs/Libraries/USB/Host/Class/HID/Inc -I../../../stm-libs/Libraries/USB/Host/Class/MSC/Inc -I../../../stm-libs/Libraries/USB/Host/Class/MTP/Inc -I../../../stm-libs/Libraries/USB/Host/Core/Inc -I../../../stm-libs/Libraries/USB/Host/Class/Template/Inc -I../../../stm-libs/Libraries/lwip/ports/STM32F4x7/FreeRTOS -I../../../stm-libs/Libraries/misc -I../../../stm-libs/Libraries/FatFs/src -I../../../stm-libs/Libraries/littleFS -I../../../stm-libs/Apps -I../../../stm-libsApps/SeqZM -I../../../stm-libs/Libraries/libc_e -I../../../stm-libs/Libraries -I../../../stm-hal-l4/Inc/Legacy -I../../../stm-hal-l4/Inc -I../../../stm-libs/Apps/Other -mthumb -mcpu=cortex-m4 -mfloat-abi=hard -mfpu=fpv4-sp-d16 -Og -g3 -T"C:/Users/Piotr/git/gPIMS-EG/src/EG/startup/EG.ld" -L"C:/Users/Piotr/git/gPIMS-EG/stm-libs/Libraries/CryptoLib" -lSTM32CryptographicV3.0.0_CM4_GCC_FPU -specs=nosys.specs -specs=nano.specs -Wl,-Map="EG.map" -static -Wl,-u,Reset_Handler  -Wl,--gc-sections -Wl,--defsym=malloc_getpagesize_P=0x80 -Wl,--start-group -lc -lm -Wl,--end-group -ffunction-sections -fdata-sections  -g -MD -MT CMakeFiles/GCEG-FW.dir/stm-libs/Apps/common/SC_Ver.c.obj -MF CMakeFiles\GCEG-FW.dir\stm-libs\Apps\common\SC_Ver.c.obj.d -o CMakeFiles/GCEG-FW.dir/stm-libs/Apps/common/SC_Ver.c.obj   -c ../../../stm-libs/Apps/common/SC_Ver.c
  In file included from ../../../stm-libs/Apps/common/SC_Ver.c:9:0:
C:\Users\Piotr\git\gPIMS-EG\stm-libs\Drivers\CAN-COB.h(267,2): warning GF07C7A44: #warning added to compile BP to change [-Wcpp]
   #warning added to compile BP to change
    ^~~~~~~
  [3/4] C:\PROGRA~2\Atollic\TRUEST~1.0\ARMTools\bin\AR097D~1.EXE -DALLOW_SOFTWARE_BKPTS=1 -DARM_MATH_CM4 -DBOOTLOADER_VERSION=1 -DCOMPILE_FOR_EG=1 -DDEBUGFILEWRITE=1 -DDEBUG_RUN_WITHOUT_CHECKS=1 -DFORCE_CUBE_USB -DHSE_VALUE=8000000UL -DSLOWSPIDEBUG=0 -DSTM32L -DSTM32L476xx -DSTM32L4xx -DUSE_EMBEDDED_PHY=1 -DUSE_FULL_ASSERT -DUSE_FULL_LL_DRIVER="" -DUSE_HAL_DRIVER -DUSE_SWOTRACE=1 -DUSE_USB_OTG_FS=1 -DUSE_USB_OTG_HS=1 -D_DEBUG=1 -D_GNU_SOURCE=1 -D__USE_SIMPLE_SWO=0 -I../../../src -I../../../src/EG -I../../../src/ZM -I../../../src/inc -I../../../stm-libs/inc -I../../../stm-libs/Drivers -I../../../stm-libs/Services -I../../../stm-libs/Services/Utils -I../../../stm-libs/RTOS/Source/include -I../../../stm-libs/RTOS/Source/portable/GCC/ARM_CM4F -I../../../stm-libs/Libraries/CMSIS/Include -I../../../stm-libs/Libraries/CMSIS/Device/ST/STM32L4xx/Include -I../../../stm-libs/Libraries/CryptoLib/Inc -I../../../stm-libs/Libraries/CryptoLib/Inc/RNG -I../../../stm-libs/drivers/USBD -I../../../stm-libs/Libraries/Middlewares/ST/STM32_USB_Device_Library/Core/Inc -I../../../stm-libs/Libraries/USB/Device/Class/CDC/Inc -I../../../stm-libs/Libraries/USB/Device/Class/MSC_HID/Inc -I../../../stm-libs/Libraries/USB/Device/Core/Inc -I../../../stm-libs/Libraries/lwip/ports/STM32F4x7 -I../../../stm-libs/Libraries/lwip/ports/STM32F4x7/arch -I../../../stm-libs/Libraries/lwip/src -I../../../stm-libs/Libraries/lwip/src/include -I../../../stm-libs/drivers/USBH -I../../../stm-libs/Libraries/USB/Host/Class/AUDIO/Inc -I../../../stm-libs/Libraries/USB/Host/Class/CDC/Inc -I../../../stm-libs/Libraries/USB/Host/Class/HID/Inc -I../../../stm-libs/Libraries/USB/Host/Class/MSC/Inc -I../../../stm-libs/Libraries/USB/Host/Class/MTP/Inc -I../../../stm-libs/Libraries/USB/Host/Core/Inc -I../../../stm-libs/Libraries/USB/Host/Class/Template/Inc -I../../../stm-libs/Libraries/lwip/ports/STM32F4x7/FreeRTOS -I../../../stm-libs/Libraries/misc -I../../../stm-libs/Libraries/FatFs/src -I../../../stm-libs/Libraries/littleFS -I../../../stm-libs/Apps -I../../../stm-libsApps/SeqZM -I../../../stm-libs/Libraries/libc_e -I../../../stm-libs/Libraries -I../../../stm-hal-l4/Inc/Legacy -I../../../stm-hal-l4/Inc -I../../../stm-libs/Apps/Other -mthumb -mcpu=cortex-m4 -mfloat-abi=hard -mfpu=fpv4-sp-d16 -Og -g3 -T"C:/Users/Piotr/git/gPIMS-EG/src/EG/startup/EG.ld" -L"C:/Users/Piotr/git/gPIMS-EG/stm-libs/Libraries/CryptoLib" -lSTM32CryptographicV3.0.0_CM4_GCC_FPU -specs=nosys.specs -specs=nano.specs -Wl,-Map="EG.map" -static -Wl,-u,Reset_Handler  -Wl,--gc-sections -Wl,--defsym=malloc_getpagesize_P=0x80 -Wl,--start-group -lc -lm -Wl,--end-group -ffunction-sections -fdata-sections  -g -MD -MT CMakeFiles/GCEG-FW.dir/stm-libs/Apps/WaveMC3/waveMC3SeqGUI.c.obj -MF CMakeFiles\GCEG-FW.dir\stm-libs\Apps\WaveMC3\waveMC3SeqGUI.c.obj.d -o CMakeFiles/GCEG-FW.dir/stm-libs/Apps/WaveMC3/waveMC3SeqGUI.c.obj   -c ../../../stm-libs/Apps/WaveMC3/waveMC3SeqGUI.c
  In file included from ../../../stm-libs/Drivers/CAN-G3M.h:31:0,
                   from ../../../stm-libs/Drivers/ioCmd.h:12,
                   from ../../../stm-libs/Services/srvCmd.h:9,
                   from ../../../src/EG/../ZM/zmServices.h:10,
                   from ../../../src/EG/ourServices.h:12,
                   from ../../../stm-libs/Apps/WaveMC3/waveMC3SeqGUI.c:5:
C:\Users\Piotr\git\gPIMS-EG\stm-libs\Drivers\CAN-COB.h(267,2): warning GF07C7A44: #warning added to compile BP to change [-Wcpp]
   #warning added to compile BP to change
    ^~~~~~~
  [4/4] cmd.exe /C "cd . && C:\PROGRA~2\Atollic\TRUEST~1.0\ARMTools\bin\AR097D~1.EXE -mthumb -mcpu=cortex-m4 -mfloat-abi=hard -mfpu=fpv4-sp-d16 -Og -g3 -T"C:/Users/Piotr/git/gPIMS-EG/src/EG/startup/EG.ld" -L"C:/Users/Piotr/git/gPIMS-EG/stm-libs/Libraries/CryptoLib" -lSTM32CryptographicV3.0.0_CM4_GCC_FPU -specs=nosys.specs -specs=nano.specs -Wl,-Map="EG.map" -static -Wl,-u,Reset_Handler  -Wl,--gc-sections -Wl,--defsym=malloc_getpagesize_P=0x80 -Wl,--start-group -lc -lm -Wl,--end-group -ffunction-sections -fdata-sections  -g   @CMakeFiles\GCEG-FW.rsp  -o GCEG-FW.elf  && cmd.exe /C "cd /D C:\Users\Piotr\git\gPIMS-EG\out\build\IoT-Debug && "C:\Program Files (x86)\Atollic\TrueSTUDIO for STM32 9.3.0\ARMTools\bin\arm-atollic-eabi-objcopy.exe" GCEG-FW.elf --output-target=binary GCEG-FW.bin -j .isr_vector -j .VERSION_INFO -j .text -j .rodata -j .ARM.extab -j .ARM -j .preinit_array -j .init_array -j .fini_array -j .data -j .RAM_VectorTable -j .RAM_DATAfunctions -j .RAM_functions -v && "C:\Program Files (x86)\Atollic\TrueSTUDIO for STM32 9.3.0\ARMTools\bin\arm-atollic-eabi-size.exe" GCEG-FW.elf --format=Berkeley""
  copy from `GCEG-FW.elf' [elf32-littlearm] to `GCEG-FW.bin' [binary]
     text      data     bss     dec     hex filename
   210428     36680   54020  301128   49848 GCEG-FW.elf

Build succeeded.

看起来 ninja 在实际构建开始之前检查依赖关系，同时忽略文件更改。有没有办法强制 cmake/ninja 在构建自定义目标后重新检查依赖项（即运行构建的 prgram）。

【问题讨论】：

标签： cmake build dependencies ninja

【解决方案1】：

看起来 ninja 在实际构建开始之前检查依赖关系，同时忽略文件更改

嘿！是的。因为来自 C 源文件的 DEPFILE 是在编译时同时生成的，所以 cmake 无法事先知道哪个文件依赖于哪个文件。它必须做两遍——首先是获取依赖项，然后是编译（这将是一个很好的特性，但实际上很难实现）。它在编译过程中一次性发生（-MD -MT 标志），因此 cmake 无法知道一个文件依赖于该标头。我也建议：

不要修改源代码树中的文件。保留 BINARY_DIR 中的所有更改。
不要修改文件。生成新文件。这更容易，一般来说，更少的状态 = 更少的问题。

试试吧：

# Inside binary_dir
set(PROJECT_BUILD_NUM_FILE ${CMAKE_CURRENT_BINARY_DIR}/gen/buildid_gen.h)
# Add #include <buildid_gen.h> to your buildid.h
add_custom_command(
     OUTPUT ${PROJECT_BUILD_NUM_FILE}
     COMMAND ${PROJECT_BUILD_NUM_UPDATE} "-p" "-x" -f ${PROJECT_BUILD_NUM_FILE}
     DEPENDS ${PROJECT_BUILD_NUM_UPDATE}
)
add_custom_target(buildid_gen
    COMMENT "Yooohooo!"
    DEPENDS ${PROJECT_BUILD_NUM_FILE}
)
add_executable(${EXECUTABLE_NAME} ${PROJECT_BUILD_NUM_FILE} ${some_other_sources})
target_add_include_directories(${EXECTABLE_NAME} PUBLIC
     # add include directory, so that buildid_gen is found
     ${CMAKE_CURRENT_BINARY_DIR}/gen
)
# this *helps*
add_dependencies(${EXECUTABLE_NAME} buildid_gen)

在构建自定义目标后，有什么方法可以强制 cmake/ninja 重新检查依赖项（即运行构建的 prgram）。

真正正确的方法 ™ 是手动跟踪所有依赖于该文件的文件（您可以考虑grep -l '#include <buildid_gen.h> 来获取列表文件）并与 cmake 进行依赖关系通信：

add_source_file_properties(${sources_that_include_buildid_gen} PROPERTIES OBJECT_DEPENDS ${PROJECT_BUILD_NUM_FILE})

如果您使用运行时接口（即long get_build_id();），跟踪依赖关系会更容易，因为只有一个实现该接口的.c 文件将依赖于生成的文件。
还有一些项目因为这样的依赖需要分两遍编译，每次编译都要先cmake .. --target buildid_gen再cmake .. --target actually_compile。
如果文件在每次构建时设置一次，execute_process 也可能更合适。

【讨论】：