我有一些 C++ 代码的 makefile(粘贴在下面)，它有一个恼人的问题，当我执行 make clean 时，依赖文件被编译(在再次被删除之前)，这使得 清理太慢了。依赖规则是

$(DEPENDDIR)%.d: %.cpp
    @mkdir -p $(DEPENDDIR)
    $(CXX) -M -MG -MT $(OBJECTDIR)$*.o $(CXXFLAGS) $< > $@

谁能看出是什么问题？

我尝试将依赖项移动到编译对象的部分，即:

$(OBJECTDIR)%.o: %.cpp
    @mkdir -p $(OBJECTDIR) # $(dir $@)
    @echo " "
    $(CXX) -M -MG -MT $@ $(CXXFLAGS) $< \
        -MF $(patsubst $(OBJECTDIR)%.o, $(DEPENDDIR)%.d, $@)

但是没有创建头文件version.hpp(并且编译失败)

KERNEL := $(shell uname -s)

PROGNAME=nextsim.exec

CXX = g++

# setting the C++ standard according to the gcc compiler version (from gcc-5.2, the default is C++14)
ifeq ($(shell echo `$(CXX) -dumpversion | cut -f1-2 -d.` \>= 5.2 | sed -e 's/\.//g' | bc),1)
    CXXFLAGS += -std=c++14
else
    CXXFLAGS += -std=c++11
endif

# add g++ option flags
CXXFLAGS += -ftemplate-depth-256 -Wno-inline \
        -fPIC -fopenmp \
        -DHAVE_CONFIG_H -D_MULTITHREADING_
ifdef NEXTSIM_COMPILE_VERBOSE
    CXXFLAGS += -v
endif

ifdef USE_OASIS
    CXXFLAGS += -DOASIS
    CXXFLAGS += -I $(NEXTSIMDIR)/modules/oasis/include
    LDFLAGS += -lgfortran
    LDFLAGS += -L $(NEXTSIMDIR)/lib -loasis
    CHAN = MPI1
    #LIBPSMILE = $(OASIS_DIR)/lib/libpsmile.${CHAN}.a $(OASIS_DIR)/lib/libmct.a $(OASIS_DIR)/lib/libmpeu.a $(OASIS_DIR)/lib/libscrip.a
endif

ifneq (,$(strip $(filter DEBUG Debug debug PROFILE Profile profile,$(NEXTSIM_BUILD_TYPE))))
    #ifeq ($(NEXTSIM_BUILD_TYPE),$(filter $(NEXTSIM_BUILD_TYPE),Debug debug))
    CXXFLAGS := $(filter-out -O3 -pthread,$(CXXFLAGS))
    CXXFLAGS += -g -O0 -DNDEBUG
ifneq (,$(strip $(filter PROFILE Profile profile,$(NEXTSIM_BUILD_TYPE))))
    CXXFLAGS += -DWITHGPERFTOOLS
endif
ifneq ($(KERNEL),Linux)
    CXXFLAGS += -Wl,-no_pie
endif
else
    CXXFLAGS += -O3 -pthread
endif

# add include paths
CXXFLAGS += -I $(NEXTSIMDIR)/core/include
CXXFLAGS += -isystem $(NEXTSIMDIR)/contrib/bamg/include # suppress annoying compilation warnings from -I
CXXFLAGS += -isystem $(NEXTSIMDIR)/contrib/mapx/include # suppress annoying compilation warnings from -I
# CXXFLAGS += -I $(NEXTSIMDIR)/contrib/interp/include

ifdef USE_ENSEMBLE
    CXXFLAGS += -DENSEMBLE
    CXXFLAGS += -I $(NEXTSIMDIR)/modules/enkf/perturbation/include
endif

ifdef USE_AEROBULK
        CXXFLAGS += -I $(AEROBULK_DIR)/include
        CXXFLAGS += -DAEROBULK
endif

# openmpi
CXXFLAGS += -I $(OPENMPI_INCLUDE_DIR)/

# petsc
CXXFLAGS += -I $(PETSC_DIR)/include

# boost
CXXFLAGS += -I $(BOOST_INCDIR)/ -I .

# netcdf
CXXFLAGS += -I $(NETCDF_DIR)/include

# gmsh
CXXFLAGS += -I $(GMSH_DIR)/include/gmsh

CXXFLAGS += -I /opt/local/include

ifeq ($(KERNEL),Linux)
    #CXXFLAGS += -std=c++0x -std=c++11 -pedantic -ftemplate-depth-256 -Wno-inline -fPIC -g -lm -pthread -v #-MMD -MP -lm -pthread -v

else

    ifeq ($(CXX),clang)
    CXXFLAGS += -stdlib=libc++
    endif

    CXXFLAGS += -I /usr/local/include #-I /opt/local/include/openmpi-mp

    #LDFLAGS += -Wl,-rpath,/usr/local/lib #-Wl,-rpath,/opt/local/lib/openmpi-mp
    #LDFLAGS += -L /usr/local/lib #-L /opt/local/lib/openmpi-mp -lmpi_cxx -lmpi -ldl -lstdc++ -lpthread

    ifeq ($(CXX),clang)
    LDFLAGS += -stdlib=libc++
    endif

endif

LDFLAGS += -L /usr/local/lib

LDFLAGS += -Wl,-rpath,$(OPENMPI_LIB_DIR)/
ifndef MACHINE_HEXAGON
    LDFLAGS += -L $(OPENMPI_LIB_DIR)/ -lmpi_cxx -lmpi -ldl -lstdc++ #-lpthread
else
    LDFLAGS += -L $(OPENMPI_LIB_DIR)/ -lmpichcxx -lmpich -ldl -lstdc++ #-lpthread #-lssl -luuid -lpthread -lrt
        LDFLAGS += -Wl,-rpath,$(BLAS_LAPACK_DIR)/lib
        LDFLAGS += -L $(BLAS_LAPACK_DIR)/lib -lsci_gnu_mp
endif

LDFLAGS += -Wl,-rpath,$(NETCDF_DIR)/lib -L $(NETCDF_DIR)/lib -lnetcdf_c++4

LDFLAGS += -Wl,-rpath,$(BOOST_LIBDIR)
LDFLAGS += -L $(BOOST_LIBDIR) -lboost_program_options -lboost_filesystem -lboost_system -lboost_serialization -lboost_mpi -lboost_date_time

LDFLAGS += -Wl,-rpath,$(PETSC_DIR)/lib
LDFLAGS += -L $(PETSC_DIR)/lib -lpetsc

LDFLAGS += -Wl,-rpath,$(NEXTSIMDIR)/lib
LDFLAGS += -L $(NEXTSIMDIR)/lib -lbamg
#LDFLAGS += -L $(NEXTSIMDIR)/lib -linterp
LDFLAGS += -L $(NEXTSIMDIR)/lib -lmapx
#LDFLAGS += -L $(NEXTSIMDIR)/lib -loasis

ifdef USE_ENSEMBLE
    LDFLAGS += -L $(NEXTSIMDIR)/lib -lpseudo2D
    LDFLAGS += -lgfortran
endif

ifdef USE_AEROBULK
        LDFLAGS += -L $(AEROBULK_DIR)/lib -laerobulk_cxx -laerobulk
        LDFLAGS += -lgfortran
endif

ifneq (,$(strip $(filter DEBUG Debug debug PROFILE Profile profile,$(NEXTSIM_BUILD_TYPE))))
#ifeq ($(NEXTSIM_BUILD_TYPE),$(filter $(NEXTSIM_BUILD_TYPE),Debug debug))
    LDFLAGS += -Wl,-rpath,/opt/local/lib
ifneq (,$(strip $(filter PROFILE Profile profile,$(NEXTSIM_BUILD_TYPE))))
    LDFLAGS += -L /opt/local/lib -lprofiler
endif
endif

LDFLAGS += -L $(NEXTSIMDIR)/lib -lnextsim

OBJECTDIR=$(NEXTSIMDIR)/objs/
DEPENDDIR=$(NEXTSIMDIR)/.deps/
BINARYDIR=bin/

# C++ files
CXXSRCDIR=.
CXXHDRDIR=.
CXXSRC=$(wildcard $(CXXSRCDIR)/*.cpp)
# We must exclude the version.hpp file from the list of header files because otherwise we get a circular dependency
CXXHDR=$(filter-out $(CXXHDRDIR)/version.hpp, $(wildcard $(CXXHDRDIR)/*.hpp))

OBJS=$(CXXSRC:%.cpp=$(OBJECTDIR)%.o)
DEPS=$(CXXSRC:%.cpp=$(DEPENDDIR)%.d)

# Rules to always execute.
.PHONY: exec clean mrproper all cleanall mrproperall

# Default action.
exec: $(PROGNAME)

# Create a header file with the git version
version.hpp: version.sh $(CXXSRC) $(CXXHDR)
    $(SHELL) -x $<

# Delete the object files.
clean:
    @echo " "
    $(RM) $(OBJS) $(DEPS)
    @echo " "

mrproper: clean
    $(RM) $(BINARYDIR)$(PROGNAME)
    @echo " "

# Rule for making the actual target
lines="=========="
Lines=$(lines)$(lines)$(lines)$(lines)$(lines)$(lines)$(lines)$(lines)
$(PROGNAME): $(OBJS) #$(CCOBJS)
    @mkdir -p $(BINARYDIR)
    @echo " "
    @echo $(Lines)$(Lines)
    @echo "Creating executable: $(BINARYDIR)$(PROGNAME)"
    @echo $(Lines)$(Lines)
    @echo " "
    $(CXX) $(CXXFLAGS) -o $(BINARYDIR)$@ $^ $(LDFLAGS)
    @echo " "
    @echo $(Lines)$(Lines)
    @echo "Created executable: $(BINARYDIR)$(PROGNAME)"
    @echo $(Lines)$(Lines)
    @echo " "

# Rules for object files from cpp files
$(OBJECTDIR)%.o: %.cpp
    @mkdir -p $(OBJECTDIR) # $(dir $@)
    @echo " "
    $(CXX) -o $@ -c $< $(CXXFLAGS)

# Make dependancy rules
$(DEPENDDIR)%.d: %.cpp
    @mkdir -p $(DEPENDDIR)
    $(CXX) -M -MG -MT $(OBJECTDIR)$*.o $(CXXFLAGS) $< > $@

# The compilation depends on this Makefile.
$(OBJS): Makefile

# Make everything
all:
    cd ..; $(MAKE) all


# Clean everything
cleanall:
    cd ..; $(MAKE) clean

# Properly clean everything
mrproperall:
    cd ..; $(MAKE) mrproper

# Properly clean & recompile
fresh:
    cd ..; $(MAKE) fresh

-include $(DEPS)

最佳答案

它正在构建，因为您正在使用 -include $(DEPS)。

参见 Including Other Makefiles

If an included makefile cannot be found in any of these directories, a warning message is generated, but it is not an immediately fatal error; processing of the makefile containing the include continues. Once it has finished reading makefiles, make will try to remake any that are out of date or don’t exist. See How Makefiles Are Remade. Only after it has tried to find a way to remake a makefile and failed, will make diagnose the missing makefile as a fatal error.

然后它继续说:

If you want make to simply ignore a makefile which does not exist or cannot be remade, with no error message, use the -include directive instead of include, like this: -include filenames…

This acts like include in every way except that there is no error (not even a warning) if any of the filenames (or any prerequisites of any of the filenames) do not exist or cannot be remade.

不可否认，这可能有不同的解释方式。我刚刚验证它确实尝试在 -include 行上重新制作文件，该行具有要重新制作的明确规则:

all:
        @echo building $@

foo.d :
        @echo building $@
        @touch $@

-include foo.d bar.d

给出:

 tmp> make all
 building foo.d
 building all

因此，这留下了一个有趣的案例来说明如何解决您的问题。对依赖文件有一个单独的规则确实会增加你的编译时间——你现在要解析每个源文件两次——一次生成 .d，一次编译。这个不好。我相信结合依赖规则和 .o 最符合您的利益。然后让依赖version.hpp的$(OBJS)的子集显式依赖它，应该就可以了。

关于c++ - 不应该应用的 makefile 规则，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/56749393/