On Makefile, how to list folders where source files reside? - makefile

For my specific case, I have many folders and subfolders with .v files. I want to compile them folder by folder. I have made this:
# find folders and subfolders to work on
DIRS := $(wildcard */)
DIRS += $(shell find $(DIRS) -type d)
# compiler flags
SRC += *.v
COMPILE = $(general_compiler_flags) $(SRC)
# run the compiler
run:
$(foreach d, $(DIRS), $(shell cd $d && $(COMPILE)))
But this takes all folders that do not have .v files and compiles them anyway. How do I make it so on my DIRS I have only the folders that house .v files?

The way you use make functions (especially shell) in your recipes is not the recommended way to use make. Assuming you have simple directory names (no spaces, no special characters), you could use something like the following, instead:
VDIRS := $(sort $(foreach d,$(DIRS),$(if $(wildcard $(d)/*.v),$(d),)))
run:
for d in $(VDIRS); do ( cd $$d && $(COMPILE); ); done
An even more make-ish solution would rely on make to iterate over all source directories instead of doing so inside a recipe:
VDIRS := $(sort $(foreach d,$(DIRS),$(if $(wildcard $(d)/*.v),$(d),)))
RUN-VDIRS := $(addprefix run-,$(VDIRS))
.PHONY: run $(RUN-VDIRS)
run: $(RUN-VDIRS)
$(RUN-VDIRS): run-%:
cd $* && $(COMPILE)
And, finally, we should consider how to avoid useless re-compilations, but this is another, more complex, story.

Related

Make doesn't realize that it's done

This is my first ever post to stackoverflow. It ought to be straightforward, but I have this problem whenever I try to write a makefile and I've never been able to figure out a satisfactory solution. Apologies if there is already a solution somewhere on the site. I couldn't find one.
What I'm trying to do is as follows:
Search my src directory for matching source files.
Compile the src code into a sandbox.
Here's my directory structure:
makefile
src1
file1.src
file2.src
src2
file3.src
subfolder
src3
file4.src
file5.src
And here's my makefile:
BUILDDIR := ./sandbox
SRC_DIRS := ./
SRCS := $(shell find $(SRC_DIRS) -name *.src)
OBJS := $(addprefix $(BUILDDIR)/o., $(notdir $(SRCS) ) )
# make print-X prints value of variable X
print-%: ; #echo $* = $($*)
.PHONY: help
help:
#echo "make <all|clean>"
.PHONY: all
all: $(OBJS)
#echo "compilation done"
$(OBJS) : $(SRCS) $(BUILDDIR)/.create
#echo "\"compiling\" $< to produce $#"
cp $< $#
$(BUILDDIR)/.create:
#echo "creating sandbox"
mkdir -p $(BUILDDIR) && cd $(BUILDDIR)
#touch $#
.PHONY: clean
clean:
#echo "deleting sandbox"
#rm -rf $(BUILDDIR)
If I type make all, the file works as expected. However, if I type make all again, instead of saying everything is up to data, I end up with the following contents in the sandbox:
o.file1.src o.file2.src o.file3.src o.file4.src o.file5.src o.o.file1.src o.o.file2.src o.o.file3.src o.o.file4.src o.o.file5.src
And the process of creating objects of objects continues recursively as many times as I type make.
Any help would be appreciated.
Incidentally, please don't post solutions that rely on the build in compile functions of make. I'm looking for a general solution that can be used for any task. For example, in this instance, I'm trying to read the source files into a tool using its command line interface.
Well, first, by having your sandbox as a subdirectory of your source directory, then using find on the source directory, every time you run it you're going to find all the files in both the source directory and all its subdirectories, including the sandbox. If the built files in the sandbox have the same names as the files in the source directories, the find will find them all.
Maybe instead of:
SRCS := $(shell find $(SRC_DIRS) -name *.src)
you want something like:
SRCS := $(shell find $(SRC_DIRS) -name $(notdir $(BUILDDIR)) -prune -o -name *.src -print)
Or, alternatively, don't make your sandbox a subdirectory of your source directory. Or, make sure that whatever name you give to the files in the sandbox directory won't match the *.src pattern you give to find.
But beyond that this is wrong:
$(OBJS) : $(SRCS) $(BUILDDIR)/.create
Suppose SRCS is foo.src bar.src, which means OBJS is sandbox/o.foo.src sandbox/o.bar.src. Then the above expands to this:
sandbox/o.foo.src sandbox/o.bar.src : foo.src bar.src sandbox/.create
This is a common mistake; people seem to think that make will go through the targets and prerequisites and match them up, so the first target depends on the first prerequisite and the second target depends on the second one etc. but of course this cannot work correctly and that's not how make works. Make treats the above as if you'd written one rule for each target, with the same prerequisites; like this:
sandbox/o.foo.src : foo.src bar.src sandbox/.create
sandbox/o.bar.src : foo.src bar.src sandbox/.create
You can see this won't do what you want at all, since the $< will always be foo.src which is clearly wrong.
You need to write a single pattern rule that will build ONE target. Then make sure the pattern applies to all the targets.
You have made things hard for yourself by trying to "flatten" a directory structure of multiple source subdirectories, into a single level of target directory (by using the $(notdir $(SRCS))). Because of this, there's no pattern that will match the same target and directory, unless you write a separate rule for every subdirectory.
Luckily there is a solution for this: VPATH. This should work for you:
VPATH := $(sort $(dir $(SRCS))
$(BUILDDIR)/o.%.src : %.src $(BUILDDIR)/.create
#echo "\"compiling\" $< to produce $#"
cp $< $#
The VPATH tells make to go look in all the directories that it found any sources in, whenever it can't find one to build.
The basic problem is that your SRCS is all files in all subdirectories that match the pattern *.src (when you run make). That means that all your object files ($(OBJS)) also match, so they copied as well.
The solution is to change your SRCS pattern so it does not match the "object" files in the build directory. Possibilities:
SRCS := $(wildcard *.src)
or
SRCS := $(shell find $(SRC_DIRS) -name $(notdir $(BUILDDIR)) -prune -false -o -name *.src)
or change the names of your "object" files so they don't end in .src
If I type make all, the file works as expected.
By which I take you to mean that directory ./sandbox exists and contains these files:
o.file1.src
o.file2.src
o.file3.src
o.file4.src
o.file5.src
However, if I type make all again, instead of saying everything is up to data, I end up with the following contents in the sandbox:
o.file1.src o.file2.src o.file3.src o.file4.src o.file5.src o.o.file1.src o.o.file2.src o.o.file3.src o.o.file4.src o.o.file5.src
Of course you do, because everything is not up to date at that point, according to the target list you create. This line ...
SRCS := $(shell find $(SRC_DIRS) -name *.src)
... defines SRCS as a list of all the files under path ./ (which is the value of SRC_DIRS) that ends in .src. That includes any such files in ./sandbox, which include all the files placed there by the first make run. You generate a corresponding target file to build for each source, and those targets corresponding to sources built by the previous make run will not, in general, exist yet. So make builds them, just as you instructed it.
The best solution, short of abandoning that automatic source identification altogether, would probably be to change your naming scheme so that outputs cannot be mistaken so easily for sources. For example, if you want the output names to have the form foo.src, then have the corresponding input named something like foo.src.in. In that particular case, you could convert from source names to target names with
OBJS := $(addprefix $(BUILDDIR)/o., $(basename $(notdir $(SRCS) ) ) )
Alternatively, you could modify the find command to skip the sandbox directory, maybe by modifying SRC_DIRS:
SRC_DIRS = src1 src2 subfolder/src3
(These specific alternatives are not mutually exclusive.)

Makefile - Compile all sub directories and output .o files in a separate directory

I have this command from my bash script
find . -type f -name "*.c" -execdir bash -c "f={}; kos-cc $KOS_CFLAGS -c {} -o $PWD/\${f%.c}.o" \;
Its job it to recursively search the current directory ($PWD) for .c files, compile them with my "kos-cc" compiler then output all the .o files into the current working directory.
I want to move parts of my bash script into a makefile and this line is the last one that stumps me. I know how to make rules that compiles c files from directory A and outputs the .o files into directory B, but here directory A isn't always the same (Since I need to handle sub directories too). How do I do the equivalent task in a Makefile either with a rule or a command?
It is not trivial because you have your sources in different directories and simple make pattern rules cannot easily handle this. But using slightly more advanced make features can make it:
SRC := $(shell find . -type f -name "*.c")
OBJ := $(patsubst %.c,%.o,$(notdir $(SRC)))
.PHONY: all
all: $(OBJ)
define COMPILE_rule
$$(patsubst %.c,%.o,$$(notdir $(1))): $(1)
kos-cc $$(KOS_CFLAGS) -c -o $$# $$<
endef
$(foreach s,$(SRC),$(eval $(call COMPILE_rule,$(s))))
.PHONY: clean
clean:
rm -f $(OBJ)
Beware: you could have several source files with the same base name in different directories. And if this happens, you will end up with a fatal conflict of object file names...
EDIT (add conflicts detection):
The following detects conflicts situations and issues an error (replace error by warning or info depending on the severity level you assign to these conflicts):
SRC := $(shell find . -type f -name "*.c")
OBJ := $(patsubst %.c,%.o,$(notdir $(SRC)))
ifneq ($(words $(OBJ)),$(words $(sort $(OBJ))))
$(error object file name conflicts detected)
endif
(sort sorts and also removes duplicates and words returns the number of space-separated words in its string parameter).

make wildcard not finding files I just copied

I would like to copy pdf files from several directories into a build directory, then use pdfunite to compile them into one pdf. The following make recipe works, but I have to run it twice because the first time through, I get an error from pdfunite - no files are found in the build directory (the PDFS variable is empty) even though they were just copied in the previous lines. How can I fix this so it works in one pass? I have simplified the recipe for clarity; I am actually pulling from various folders and making some pdfs on the fly as well, so I can't easily concatenate a full list of files from various subfolders (folder1 and folder2 in the example) to pass to pdfunite.
notebook:
mkdir -p $(out)
mkdir -p $(build)/notebook
$(eval PR := $(sort $(wildcard $(data)/folder1/*.pdf)) )
cp $(PR) $(build)/notebook
$(eval SR := $(sort $(wildcard $(data)/folder2/*.pdf)) )
cp $(SR) $(build)/notebook
$(eval PDFS := $(sort $(wildcard $(build)/notebook/*.pdf)) )
pdfunite $(PDFS) $(out)/notebook.pdf
Your Makefile is not in line with make's philosophy. You are using make as another scripting language, while make is more than this. It compares targets and prerequisites dates, based on this decides which must be built or re-built, and passes the recipes to the shell. So, for your particular problem, you should rather try something like:
PR := $(wildcard $(data)/folder1/*.pdf)
SR := $(wildcard $(data)/folder2/*.pdf)
PDFS1 := $(patsubst $(data)/folder1/%.pdf,$(build)/notebook/%.pdf,$(PR))
PDFS2 := $(patsubst $(data)/folder2/%.pdf,$(build)/notebook/%.pdf,$(SR))
PDFS := $(sort $(PDFS1) $(PDFS2))
.PHONY: notebook
notebook: $(out)/notebook.pdf
$(PDFS1): $(build)/notebook/%.pdf: $(data)/folder1/%.pdf | $(build)/notebook
cp $< $#
$(PDFS2): $(build)/notebook/%.pdf: $(data)/folder2/%.pdf | $(build)/notebook
cp $< $#
$(build)/notebook $(out):
mkdir -p $#
$(out)/notebook.pdf: $(PDFS) | $(out)
pdfunite $(PDFS) $#
The variables definitions are reasonably straightforward: patsubst, as its name says, substitutes strings. The target: pattern: prerequisites is a static pattern rule. And the prerequisites after | are order-only prerequisites.
What this makefile says, basically, is that $(out)/notebook.pdf depends on a set of pdf files in $(build)/notebook/ and that these pdf files depend on source pdf files with the same basenames in $(data)/folder1/ and $(data)/folder2/. It also says that directories must be created before being populated. Thanks to all this only what needs to be done will be done, no more, no less. And it is more in line with make's philosophy.
If you have many source folders and do not want to replicate the copying rules, you can use more advanced features like:
FOLDERS := folder1 folder2
.PHONY: notebook
notebook: $(out)/notebook.pdf
define MY_rule
$(1)_SRCS := $$(wildcard $$(data)/$(1)/*.pdf)
$(1)_DSTS := $$(patsubst $$(data)/$(1)/%.pdf,$$(build)/notebook/%.pdf,$$($(1)_SRCS))
PDFS += $$($(1)_DSTS)
$(1)_DSTS: $$(build)/notebook/%.pdf: $$(data)/$(1)/%.pdf | $$(build)/notebook
cp $$< $$#
endef
$(foreach f,$(FOLDERS),$(eval $(call MY_rule,$(f))))
$(build)/notebook $(out):
mkdir -p $#
$(out)/notebook.pdf: $(PDFS) | $(out)
pdfunite $(PDFS) $#
I would do another way.
PR:=$(sort $(wildcard $(data)/folder1/*.pdf))
SR:=$(sort $(wildcard $(data)/folder2/*.pdf))
PDFS=$(sort $(wildcard $(build)/notebook/*.pdf))
all: copy
pdfunite $(PDFS) $(out)/notebook.pdf
copy:
mkdir -p $(out)
mkdir -p $(build)/notebook
cp $(PR) $(build)/notebook
cp $(SR) $(build)/notebook
.PHONY: all copy
Please check: PDFS= and not PDFS:=. If you use simple = the variable's value will calculate when it needed (not sooner!).
When you run make it want to build all. The all's requirement is copy - so make does some mkdir and cp. After it return the all: the value of PDFS is needed so will evalute now - we have many-many pdf in $(build)/notebook :)

patsubst with multiple wildcards

I have a directory structure like
packages/
foo/
lib/
a.js
b.js
bar/
lib/
c.js
d.js
and I'm trying to write a simple Makefile to run the source files through a compiler and output the result of compiling packages/foo/lib/a.js to packages/foo/build/a.js. In the past, I've done something like
JS = $(shell find packages/foo/lib -name "*.js")
BUILD = $(patsubst packages/foo/lib/%.js, packages/foo/build/%.js, $(JS))
.PHONY: all
all: $(BUILD)
packages/foo/lib/%.js: packages/foo/build/%.js
# Compile $^ and output to $#
which works great. However, I'm now doing
JS = $(shell find packages/*/lib -name "*.js")
BUILD = $(patsubst ...)
The problem here is that patsubst doesn't seem to like multiple % wildcards (ie packages/%/lib/%.js). However, if I use packages/%.js, then I can't know which directory to use in the substitution. I'm convinced there's a very simple way to do this that I can't find in the make docs.
To define BUILD, you could use the stupid but simple solution:
BUILD = $(subst /lib/,/build/,$(JS))
as long as you aren't worried about additional "lib" and "build" pathname components in your source.
However, this leaves you with the problem of how to define the actual Makefile rules, unless you want to manually specify a rule for each directory foo, bar, etc.
Instead, maybe try something like this (remember to replace spaces with tabs again where appropriate, if you cut and paste):
PACKAGES = $(wildcard packages/*)
ALL :=
define add_package
JS := $$(shell find $(1)/lib -name "*.js")
BUILD := $$(patsubst $(1)/lib/%.js, $(1)/build/%.js, $$(JS))
$(1)/build/%.js:: $(1)/lib/%.js
echo COMPILE $$^ '->' $$#
cp $$^ $$# # super fast compiler!
ALL += $$(BUILD)
endef
$(foreach p, $(PACKAGES), \
$(eval $(call add_package,$(p))))
all: $(ALL)
This evaluates a template for each package directory, so you can put anything in there, as long as you get the fiddly doubling of dollar signs correct.

make wildcard subdirectory targets

I have a "lib" directory in my applications main directory, which contains an arbitrary number of subdirectories, each having its own Makefile.
I would like to have a single Makefile in the main directory, that calls each subdirectory's Makefile. I know this is possible if I manually list the subdirs, but I would like to have it done automatically.
I was thinking of something like the following, but it obviously does not work. Note that I also have clean, test, etc. targets, so % is probably not a good idea at all.
LIBS=lib/*
all: $(LIBS)
%:
(cd $#; $(MAKE))
Any help is appreciated!
The following will work with GNU make:
LIBS=$(wildcard lib/*)
all: $(LIBS)
.PHONY: force
$(LIBS): force
cd $# && pwd
If there might be something other than directories in lib, you could alternatively use:
LIBS=$(shell find lib -type d)
To address the multiple targets issue, you can build special targets for each directory, then strip off the prefix for the sub-build:
LIBS=$(wildcard lib/*)
clean_LIBS=$(addprefix clean_,$(LIBS))
all: $(LIBS)
clean: $(clean_LIBS)
.PHONY: force
$(LIBS): force
echo make -C $#
$(clean_LIBS): force
echo make -C $(patsubst clean_%,%,$#) clean
There is also a way of listing sub-directories with gmake commands only, without using any shell commands:
test:
#echo $(filter %/, $(wildcard lib/*/))
This will list all sub-directories with trailing '/'. To remove it you can use the substitute pattern:
subdirs = $(filter %/, $(wildcard lib/*/))
test:
#echo $(subdirs:%/=%)
Then to actually create rules executing makefiles in each sub-directory you can use a small trick - a phony target in a non-existent directory. I think in this case an example will tell more than any explanation:
FULL_DIRS =$(filter %/, $(wildcard lib/*/))
LIB_DIRS =$(FULL_DIRS:%/=%)
DIRS_CMD =$(foreach subdir, $(LIB_DIRS), make-rule/$(subdir))
make-rule/%:
cd $* && $(MAKE)
all: DIRS_CMD
Basically, target 'all' lists all sub-directories as prerequisites. For example, if LIB_DIRS contained lib/folder1 lib/folder2 then the expansion would look like this:
all: make-rule/lib/folder1 make-rule/lib/folder2
Then 'make', in order to execute rule 'all', tries to match each prerequisite with an existing target. In this case the target is 'make-rule/%:', which uses '$*' to extract the string after 'make-rule/' and uses it as argument in the recipe. For example, the first prerequisite would be matched and expanded like this:
make-rule/lib/folder1:
cd lib/folder1 && $(MAKE)
What if you want to call different targets than all in an unknown number of subdirectories?
The following Makefile uses macros so create a forwarding dummy-target for a number of subdirectories to apply the given target from the command line to each of them:
# all direct directories of this dir. uses "-printf" to get rid of the "./"
DIRS=$(shell find . -maxdepth 1 -mindepth 1 -type d -not -name ".*" -printf '%P\n')
# "all" target is there by default, same logic as via the macro
all: $(DIRS)
$(DIRS):
$(MAKE) -C $#
.PHONY: $(DIRS)
# if explcit targets where given: use them in the macro down below. each target will be delivered to each subdirectory contained in $(DIRS).
EXTRA_TARGETS=$(MAKECMDGOALS)
define RECURSIVE_MAKE_WITH_TARGET
# create new variable, with the name of the target as prefix. it holds all
# subdirectories with the target as suffix
$(1)_DIRS=$$(addprefix $(1)_,$$(DIRS))
# create new target with the variable holding all the subdirectories+suffix as
# prerequisite
$(1): $$($1_DIRS)
# use list to create target to fullfill prerequisite. the rule is to call
# recursive make into the subdir with the target
$$($(1)_DIRS):
$$(MAKE) -C $$(patsubst $(1)_%,%,$$#) $(1)
# and make all targets .PHONY
.PHONY: $$($(1)_DIRS)
endef
# evaluate the macro for all given list of targets
$(foreach t,$(EXTRA_TARGETS),$(eval $(call RECURSIVE_MAKE_WITH_TARGET,$(t))))
Hope this helps. Really helpfull when dealing with paralelism: make -j12 clean all in a tree with makefiles having these targets... As always: playing with make is dangerous, different meta-levels of programming are too close together ,-)

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