I'm using automake.
I'd like to have a script run each time I run 'make'.
This script does a git diff and generates an MD5 sum of the diff.
The hash is written as a #define in repos_version.h
e.g.:
#define REPOS_DIFF "-190886e9f895e80c42cf6b426dc85afd"
The script only rewrites this file if it doesn't exist or if the diff has is different to what is in repos_version.h already. But the script needs to be run for each make.
main.c includes repos_version.h and prints out the hash when the executable is run.
Here's Attempt 1 for Makefile.am
all: config.h
#chmod +x gen_diff_hash.sh
#./gen_diff_hash.sh
$(MAKE) $(AM_MAKEFLAGS) all-recursive
This work, but I get the following error
Makefile:1234: warning: overriding recipe for target all'
Makefile:734: warning: ignoring old recipe for targetall'
Here's Attempt 2 for Makefile.am
all-local:
#chmod +x gen_diff_hash.sh
#./gen_diff_hash.sh
main.c: repos_version.h
However, this doesn't work, as all-local seems to be run too late. A second run of 'make' does get the desired result, but that's not a runner.
So neither are great.
Any ideas?
I've been reading through the automake hooks documentation, but I can't see anything that suits my needs.
You could ensure the script is always run every time Make loads the Makefile, by executing it via $(shell ./gen_diff_hash.sh) and assigning it to a throwaway variable (or using it in some other construct like an ifeq or something).
Note, that this is not POSIX, and on Make implementations other than GNU this isn't valid syntax. GNU Make 4.x supports using VAR != ./gen_diff_hash.sh as well, which is compatible with BSD Make at least.
But maybe it would be a better idea to create a .PHONY: gendiff target that runs the script, and make the header depend on this gendiff. The target would then be re-evaluated every time Make checks if repos_version.h is up-to-date, rather than every time Make is run at all.
Related
I'm using this makefile as an example:
https://gist.github.com/mihaitodor/bfb8e7ad908489fdf3ceb496573f306a
Before compiling/linking I need to do a pre-stage, consisting of cd to a directory and run a script. Without the pre-stage it compiles & links fine.
I think I need to change the all rule:
all : $(TESTS)
I have tried this:
all : cd /bla/bla ./my_script $(TESTS)
and I have tried this:
all :
cd /bla/bla ./my_script
$(TESTS)
but it stops the compile/linking stage.
Given the URL above, where should I insert my pre-stage?
The short answer is you should likely create a new recipe, and make any bottom level target that is dependent on your script running be dependent on it. Something like:
.ran_my_script: $(GTEST_SRCS_)
cd /bla/bla ./my_script
touch $#
test_mihai.o gtest_main.o gtest.o : .ran_my_script
This way it will run your script before it attempts to generate any of the listed targets. It then touches a file $# (.ran_my_script). This will then be newer than any of the .o files meaning the script will not rerun unless someone modifies one of the scripts dependencies (i.e. $(GTEST_SRCS_)). You'll have to figure out what artifcats are actually dependent on your script, and what artifacts your script is dependent on.
Notice that if any of the sources change, then .ran_my_script will be considered out of date, as will anything that depends on it. This means that if you modify any source, it will rebuild all .o files. I'm assuming this is what you want.
Because I'm assuming you're new to makefiles, I will point out two things: first $# resolves to the target name (.ran_my_script in the above example), and second, that the last line of this causes .ran_my_script to be a dependency of test_mihai.o and friends -- but because it does not have any recipes associated with it, this line does not override any other recipes against the same targets specified prior to or later on in the makefile.
As to why what you were doing doesn't work:
all: cd /bla/blah ./my_script $(TESTS)
indicates that the target all is dependent on the targets cd, /bla/bla, ./my_script, and $(TESTS). It will attempt to build all of these before it builds all. Of course, you likely do not have a rule to build cd, etc, so this will fail.
Your next example,
all :
cd /bla/bla ./my_script
$(TESTS)
You create a target all, with two recipes. First, it will attempt to run your script, and then it will attempt to run whatever $(TESTS) resolves to. Notice that $(TESTS) in this case is not a bash command, so this would fail as well.
You might be tempted to do something like this:
all : $(TESTS)
cd /bla/bla ./my_script
but this would cause your script to be run as part of the all target, which runs after everything in $(TESTS) has already been completed.
I'm running make (GNU Make 3.82) with a recursive Makefile.
I'm running make -j2 in order to spawn only 2 processes in parallel.
The internal Makefile is called with $(MAKE).
However, it looks like the internal Makefile (which was started by the main Makefile) spawns processes infinitely as if it was given -j and not -j2.
Trying to verify this, I dumped the environment variables of the child "make":
# pgrep -a make
17218 make -j2
17227 make -C obj_dir/ -f Vf1_package.mk ...
# strings /proc/17227/environ
...
MAKEFLAGS= --jobserver-fds=3,4 -j
...
MAKEFLAGS is not set explicitly anywhere, and -j is only provided in the command line and doesn't appear anywhere in the makefiles. So it seems like "make" itself decided to strip the "2" from the -j argument when composing the MAKEFLAGS for the child "make".
Any idea what could cause "make" to set MAKEFLAGS to -j instead of -j2?
Update 1
I've identified the problem, but I still don't understand why it happens and how to fix that.
The problem is that the job server doesn't work well when the sub-make is running under SCL context.
This is required because I need the sub-make to use specific gcc toolchain.
SCL = scl enable devtoolset-8
...
sub_make:
$(SCL) "$(MAKE) -C $(SUB_MAKE_DIR) ... "
When running like this, the sub-make spawns infinite number of jobs. When SCL is removed, it works as expected.
Why does SCL interfere with make's job server?
How can I solve this? I know I can enable SCL before running the external Makefile, but I would like to control the toolset from within the Makefile.
Update 2
It seems to be related to the fact that SCL changes PATH environment variable. On the new PATH, "make" is newer ("GNU Make 4.2.1").
So it seems that make job server fails if the top level make is running old GNU Make 3.82 and the sub make is running newer 4.2.1 make, maybe something changed between these versions in the way make communicates with the sub-make.
There's nothing wrong here. The top-level make knows how many total jobs there are and it arranges for all the sub-makes to share those jobs through the jobserver (that's what the --jobserver-fds entry in MAKEFLAGS is for). The sub-makes don't need to know how many total jobs there are, they just need to know how to ask if they can start a new job.
In the very old version of GNU make you are using there is no way, from a sub-make, to know what the specific -j number for this build.
Starting with GNU make 4.2, make will add the specific -j value to MAKEFLAGS for informational purposes even though it's still not used.
EDIT
I don't know anything about scl or how it works. But, the GNU make jobserver works by sharing file descriptors across all the sub-makes. If this scl tool is interfering with that, say by forcing all file descriptors to be closed, or running the sub-make inside a docker image where obviously it can't access these shared file descriptors, or some similar thing, then it clearly cannot work with the jobserver feature and you'll have to run the entire make inside the scl.
An option is to not put the -j on the outer make but instead run a single inner make using -j, inside scl.
Can you run make --print-data-base and check if you get proper value of -j.
May be execute a simple test example as shown below where you can test to check if gnu make is able to compile multiple files in parallel to generate object files and is giving correct values of -j:
# .SILENT:
.PHONY:compile objs
TARGET = program.exe
CC=gcc
SOURCES = file_1.c file_2.c file_3.c
OBJ_FILES:= $(SOURCES:.c=.o)
objs: $(OBJ_FILES)
%.o: %.c
$(CC) $(FLAGS) -c $< -o $#
all: test
# Enable parallel compilation
compile:
make -j ${NUMBER_OF_PROCESSORS} objs
link : compile $(TARGET)
$(TARGET): $(OBJ_FILES)
$(CC) $(FLAGS) $(OBJ_FILES) -o $#
test: link
# Execute test script
echo "Executing test script"
Command to execute : make test
This will help you debug and also check if there is issue of gnu-make or some internal bug or make is unable to run in parallel as it did not find anything. I have use ${NUMBER_OF_PROCESSORS} to use all the available processors, you can change it's value and test different runs as per your need.
EDIT
Unfortunately I am not aware about sc1.If scl is the root cause identified, then option would be run the entire make inside sc1. or maye be would be good to test once by explicitly passing -j2 inside the sc1 as maybe global flags are not getting passed to SC1.
I have a project to compile with a lot of makefiles including a clean command. That's why i always have to start over again if there is an error (because the clean command is called in many Makefiles)
Question:
Is there any possibility to tell make to ignore the clean command? I would have to touch > 100 Makefiles otherwise. I would like make to start on the last error, not compiling all done stuff again
Example Makefile entries:
clean: cleansubdirs $(DIR) $(DIR1)
$(DIR2)
It's possible to redefine the recipe of an explicit target as simple as that:
noclean.mk
clean:;
cleansubdirs:;
# more stuff...
Now run make -f Makefile -f noclean.mk and it will work without actual cleaning files. However, make will issue several warnings about "overriding/ignoring old recipes".
From the docs:
Usually when a recipe line fails, if it has changed the target file
at all, the file is corrupted and cannot be used--or at least it is not
completely updated. Yet the file's time stamp says that it is now up to
date, so the next time 'make' runs, it will not try to update that file.
The situation is just the same as when the shell is killed by a signal;
*note Interrupts::. So generally the right thing to do is to delete the
target file if the recipe fails after beginning to change the file.
'make' will do this if '.DELETE_ON_ERROR' appears as a target. This is
almost always what you want 'make' to do, but it is not historical
practice; so for compatibility, you must explicitly request it.
So, here I have a makefile:
# The idea here is to auto-generate the file ('make.include')
# and to use it as a makefile.
# For simplicity, I replaced the "auto-generate" part, with "touch".
# I also simplified the dependency-tree with 'phony'.
# In practice, we re-generate, only when "need" to.
make.include : phony
+touch '$#'
make -f '$#'
.PHONY: phony
Running:
$ make -q
I get:
touch 'make.include'
make: *** Deleting file 'make.include'
Now, i don't see how to prevent make from deleting this newly auto-generated 'make.include' (which may well be quite a costly process to re-run), unless i resort to the .PRECIOUS special target.
But, demanding the user to explicitly define their "precious" targets, is not in-line with that quote from the docs above. Right?
This arises because of your use of + in +touch '$#' and executing make with the -q option. From the GNU Make Manual the -q option is
“Question mode”. Do not run any recipes, or print
anything; just return an exit status that is zero if the specified
targets are already up to date, one if any remaking is required, or
two if an error is encountered. See Instead of Executing Recipes.
The + symbol is only relevant when make is executed with the -t, -n or -q options and it tells make to execute any commands it precedes make is executed with any of the options -t, -n or -q. So, when you execute your current makefile with make -q you are asking make to check if everything is up to date without running any commands but because you've specified + before touch '$#' make must execute this command. To then leave everything the way it was before you executed make -q make must delete the file it created with +touch '$#'.
To answer your question specifically. If you don't want make to delete make.include then you can run make without the -q option on the makefile specified in your question.
However, the recipe for a target, i.e. make.include should not call its self with make -f make.include. It would probably be better to rewrite the makefile so that the recipe for make.include only creates make.include and it is then called with make -f make.include in another recipe.
make.include:
+touch $#
all: make.include
make -f $<
I am absolutely new in gfortran+minGW.
I need to create makefile.
When I run
$ gfortran -c q.f
All is ok!
But how can I run makefile like this?
CC = gfortran
q.o : q.f
$(CC) -c q2.o q2.f
I receive error “CC: command not found”.
(OS – Win 7 (64))
Tanks!!!
It kind of looks like you're trying to run the makefile as a regular script. Try
$ make
or
$ make -f mymakefilename
if you named the file something other than "makefile" or "Makefile".
You can potentially just execute the makefile, but if so you need a "shebang" line, something like
#!/usr/bin/make
at the top of the file, but frankly hardly anyone uses that option. Just use the make(1) command.
Update
It's because they're in the wrong order. Makefiles process (by default) the first target in the file. When you run make it sees the rule to make, q.o from q.f, it compiles it, and says, "Okay, I'm done."
If you put the q.exe target first, it says "Hmmm, I want to build q.exe and to do that I need a q.o. Do I have a q.o? No? Okay, hen I'll build a q.o. I have a rule for that -- I can build a q.o from q.f. okay, that's done. Now can I build q.exe? Oh, yes, I can. I'll build q.exe. Anything? Nope, I'm done."
If you were to use the commend
$ make q.exe
then you'd explicitly tell make to make q.exe, which would cause the same thing to happen, but better you should reorder your makefile and get used to the way they work.