Problems with GNU Make dynamic rules - makefile

I'm trying to setup a Makefile to compile my Rust project. To speed things up I don't want to recompile the whole project all at once. Rust allows you to create libraries that can then be linked into the main executable. Given two files src/iomrascalai.rs (the main program) and src/board/mod.rs (the library) to compile it by hand it would work like this:
$ rustc --out-dir lib src/board/mod.rs
$ ls lib/
libboard-d085aa56-0.0.rlib
$ rustc --out-dir bin -L lib src/iomrascalai.rs
$ ls bin/
iomrascalai
What I'm trying to do in the Makefile is to define dynamic rules to compile the libraries. I'm trying to do it like that as the mapping from source file (src/board/mod.rs) to library name (lib/libboard-d085aa56-0.0.rlib) is non-trivial. However, I can't seem to make it work:
MAIN = src/iomrascalai.rs
CRATES = src/board/mod.rs
LIBS = $(foreach crate, $(CRATES), $(call TO_LIB, $(crate)))
all: exe
exe: $(MAIN) $(LIBS)
rustc --out-dir bin -L lib $(MAIN)
TO_LIB = $(addprefix lib/, $(shell rustc --crate-file-name $(1)))
define COMPILE_CRATE
$(call TO_LIB, $(1)): $(1)
rustc --out-dir lib $(1)
endef
$(foreach crate, $(CRATES), $(eval $(call COMPILE_CRATE, $(crate))))
Running make results in the following error:
$ make
rustc --out-dir bin -L lib src/iomrascalai.rs
src/iomrascalai.rs:22:1: 22:20 error: can't find crate for `board`
src/iomrascalai.rs:22 extern crate board;
^~~~~~~~~~~~~~~~~~~
error: aborting due to previous error
make: *** [exe] Error 101
So the libraries aren't compiled which means that the main program can't be compiled. When I try to run make to compile the lib target then it works:
$ rustc --crate-file-name src/board/mod.rs
libboard-d085aa56-0.0.rlib
$ make lib/libboard-d085aa56-0.0.rlib
rustc --out-dir lib src/board/mod.rs
So for some reason the exe doesn't honor the prerequisites even though the rules are defined ...

Recursively expanded make variables (those which are assigned with =) are expanded whenever the variable is substituted. That means, other variables you use need to be defined before. In your case, you need to move up the definition of TO_LIB a few lines (at least above the exe rule since the expansion of LIBS need to have TO_LIB available there)

Related

Can GCC ignore nonexisting directories?

I have two projects: mylib and myproj
mylib compiles into a shared object.
myproj uses mylib.
I linking myproj using:
g++ -L../../mylib/Release myproj.o -lmylib
That works fine on my development machine.
On another machine, mylib.so is located in /usr/local/lib. Therefore there is no need for -L.
It compiles fine without the -L.
But, once I compile it with the same command (with the -L), it responds with
g++: error: ../../mylib/Release: No such file or directory
I would like myproj to compile on both machines with the same command.
Is there a way to make it ignore non existing directories?
It doesn't seem to care whether a full path doesn't exist, it complains only for relative paths.
You want to use Makefiles as often as you can since they make things a lot easier. In a defined Makefile you could check for the directory first. It could be sth like this:
all:
if [ -d "mylib" ]; then
g++ -L../../mylib/Release myproj.o -lmylib
else
g++ myproj.o -lmylib
fi
Of course you can use Variables like CC, etc. This is just a basic example.

Automatically create .OBJDIR subdirectories

OS: FreeBSD 11.0-RELEASE
I have the following directory structure:
/xxx/obj/
/xxx/src/deep.cpp
/xxx/flat.cpp
/xxx/makefile
The content of makefile is as follows:
flat.out: flat.o
deep.out: src/deep.o
I have no problem building flat:
/xxx $ make flat.out
c++ -O2 -pipe -c /xxx/flat.cpp -o flat.o
cc -O2 -pipe flat.o -o flat.out
/xxx $ ls obj
flat.o flat.out
But when I try to build deep it fails:
/xxx $ make deep.out
c++ -O2 -pipe -c /xxx/src/deep.cpp -o src/deep.o
error: unable to open output file 'src/deep.o': 'No such file or directory'
1 error generated.
*** Error code 1
Stop.
make: stopped in /xxx
If I then create /xxx/obj/src manually it succeeds:
/xxx $ mkdir obj/src
/xxx $ make deep.out
c++ -O2 -pipe -c /xxx/src/deep.cpp -o src/deep.o
cc -O2 -pipe src/deep.o -o deep.out
/xxx $ ls obj
deep.out flat.o flat.out src
/xxx $ ls obj/src
deep.o
According to this source bmake (aka bsdmake?) supports automatic creation of out-of-source OBJDIRs, but I cannot figure out how exactly.
How do I configure bmake to create the relevant directories automatically, in the general case?
Automatic creation of out-of-source OBJDIRs is supported but not in the sense you seem to expect it. Creation of out-of-source OBJDIRs can be implemented with bmake(1) directives but is not supported by the bmake(1) program itself. That said,
If you use bmake(1) directives shipped with FreeBSD to build your project, then the creation of OBJDIRs is supported and implemented by the obj target, so that the command make obj will create the OBJDIRs. See the file bsd.obj.mk for further documentation and implementation details. FreeBSD sources contain a lot of examples of programs using these directives to build.
If you use bmake(1) directives shipped as the (portable) bsdowl package, then the creation of OBJDIRs is supported and implemented by the target obj so that the command make obj or the command make preparatives using a more general target will create the OBJDIRs. The example directory contains several C-based examples showing how to prepare your Makefiles to build your project with the bsdowl package.
If you use custom bmake(1) directives, then you will have to implement a target taking care of this creation yourself. The file bsd.obj.mk is definitely a good source to get started with this.
An important point to note, is that bmake(1) determines its actual working directory before processing any targets, which means that it is almost always the right thing to do to execute the target requesting the creation of OBJDIRs on its own. Because of this, the command bmake obj all from your example would fail with the same error message you reported above. The correct invocation would instead be bmake obj && bmake all, since the second bmake(1) process has now the chance to change to the OBJDIR created by the previous run.

How to force compiler to compile same source file every time used in different shared libraries in cmake? [duplicate]

I have a project directory structure of:
Root
Source
Common
MyFolder
++ My 3 source files and header
When I am building my project it generates 3 to 4 shared libraries. Lib1 compiled using c++98 and others using c++11. Flags are added in CmakeList.txt which is at root.
I need my 3 source files to be compiled for Lib1 and for other Libs as as well. but here what happens is compiler is first compiling my source file for lib using c++11 and then it is trying to use same .o file for Lib1 as well. So for .o file which is generated using c++11 is throwing exception when same is used for c++98 compiled library.
So how do write this in CmakeList.txt such that compiler rather than trying to use same .o file will compile source file again for Lib1(c++98 compiled library)
Is there any flag I can specify so that it won't take precompiled .o file and will compile it again ?
Here flags are not being overridden for different shared libraries but actually same object file by make file is being used for different flags
This is sort of counter to how makefiles and cmake usually work.
Most users consider it really important that make performs an incremental build.
The usual way with makefiles is to do make clean which is supposed to remove any binaries and object files that were created.
However, sometimes I write cmake scripts that use globbing over the source directory to assemble the project. (That means, it says "just grab all *.cpp files in the /src folder and make an executable from them".) A makefile cannot check what files in a directory, so the make build will be broken after I add a new file, and make clean won't fix it -- the whole makefile will need to be regenerated by cmake.
Usually what I do is, I write a simple bash script, named rebuild.sh or something,
#!/bin/bash
rm -rf build
mkdir build
cd build
cmake ..
make -j3
./tests
And I put that in the root of my repository, and add /build to my .gitignore. I call that when I want to do a full rebuild -- it nukes the build directory, so its foolproof. When I want an incremental rebuild, I just type make again in the /build directory.
The rebuild.sh script can also serve a double purpose if you use travis-ci for continuous integration.
Most build system assume the compiled objects remain the same within the same pass. To avoid shooting your foot I would suggest telling the build system they were actually different objects, while still compiled from same source files.
I'm not familiar with cmake but this is how you do with make:
For example you have a a.cpp which you want to compile 2 times for different compiler options:
#include <stdio.h>
int main(int argc, char* argv[]) {
printf ("Hello %d\n", TOKEN);
return 0;
}
And the Makefile would looks like:
SRC := $(wildcard *.cpp)
OBJ_1 := $(patsubst %.cpp,%_1.o,$(SRC))
OBJ_2 := $(patsubst %.cpp,%_2.o,$(SRC))
all: pass1 pass2
pass1: $(OBJ_1)
gcc -o $# $(OBJ_1) -lstdc++
pass2: $(OBJ_2)
gcc -o $# $(OBJ_2) -lstdc++
%_1.o: %.cpp
gcc -DTOKEN=1 -c $< -o $#
%_2.o: %.cpp
gcc -DTOKEN=2 -c $< -o $#
clean:
rm -f $(OBJ_1) $(OBJ_2)
What I do here is generate two different list of object from the same source files, which you can even do the same for dependency(-MMD -MP flags).

Compile multiple executables from multiple source directories to single bin directory using makefile

I'm trying to create a makefile for a suite of programs that I am working on. The programs are all written in fortran and the source files are contained in different directories. I can't seem how to figure out how to get things to work. My current sumfile is
#Compiler and compiler flag variables
FCOMP=/usr/local/bin/gfortran
F_FLAGS=-O2 -fbounds-check -Wall
F_FLAGSDB=-g -fbounds-check -Wall
#paths to libraries
COMMON_LIB=/usr/local/lib/libspc_common.a
SPICE_LIB=/usr/local/lib/spicelib.a
# Paths to directories
BIN_DIR=BIN
# Get file names of component source files
#get names of files in src1
FORT_FILES=$(wildcard ./SRC1/*.f)
#get names of files in src2
FORTFILES+=$(wildcard ./SRC2/*.f)
#get names of files in src3
FORTFILES+=$(wildcard ./SRC3/*.f)
#get file names for output
EXE_FILES=$(addprefix $(BIN_DIR),$(notdir $(patsubst %.f, % , $(FORTFILES))))
# make commands
# Set the default option to compile the library with optimization
default: all
# create all command
all: $(EXE_FILES)
#echo toolkit has been built with optimization
#If compiling for debugging replace the compiler flags to remove optimization and add debugging
debug: F_FLAGS=$(F_FLAGSDB)
#Run compiler with debugging flags
debug: $(EXE_FILES)
#echo toolkit has been built with debugging
# Compile all of the source files into executables
$(EXE_FILES): % : %.f
$(FCOMP) $(F_FLAGS) $^ $(COMMON_LIB) $(SPICE_LIB) -o $(BIN_DIR)/$#
# install the library in /usr/local/lib
install:
cp -p $(BIN_DIR)* /usr/local/bin/toolkit/
# remove executable files for a clean build
clean:
rm $(BIN_DIR)*
The problem I am running into is that I get the following error when I try to run make:
make: *** No rule to make target `Display.f', needed by `Display'. Stop.
which I am assuming is because I have lost the directory that the source file comes from. Can someone help me here? I am totally stuck and don't know how to proceed.
In addition (this is more a general question about make), is there a way to tell make to recompile everything if the COMMON_LIB changes?
Thanks for your help!
Suppose your source files are
SRC1/alpha.f
SRC1/beta.f
SRC2/gamma.f
SRC3/delta.f
1) There is a flaw here:
EXE_FILES=$(addprefix $(BIN_DIR),$(notdir $(patsubst %.f, % , $(FORTFILES))))
This will produce
BINalpha BINbeta BINgamma BINdelta
when I think you intended
BIN/alpha BIN/beta BIN/gamma BIN/delta
A simple fix:
EXE_FILES=$(addprefix $(BIN_DIR)/,$(notdir $(patsubst %.f, % , $(FORTFILES))))
2) Now look at the static pattern rule:
$(EXE_FILES): % : %.f
...
So to build BIN/alpha, Make must first find BIN/alpha.f, which doesn't exist. To make it look for alpha.f, do this:
$(EXE_FILES): $(BIN_DIR)/% : %.f
...
3) How to find the sources?
You could do some delicate coding to help Make remember where it found alpha.f, but there's no need when we can use the vpath directive:
vpath %.f SRC1 SRC2 SRC3
4) One last look at that rule:
This command:
$(FCOMP) $(F_FLAGS) $^ $(COMMON_LIB) $(SPICE_LIB) -o $(BIN_DIR)/$#
Will produce e.g. BIN/BIN/alpha, which is silly. A non-PHONY Make rule should produce a file whose name is the target of the rule. It prevents a lot of trouble.
$(FCOMP) $(F_FLAGS) $^ $(COMMON_LIB) $(SPICE_LIB) -o $#
A few further refinements may be possible, once you have this working perfectly.

rebar compile fails with bitcask - "errno.h": no such file

I am new to Erlang, so i am going through Joe Armstrong's book "Programming Erlang". In chapter 25 there's an example on how to work with rebar. I followed the instructions and created a Makefile
all:
test -d deps || rebar get-deps
rebar compile -v
#erl -noshell -pa './deps/bitcask/ebin' -pa './ebin' -s myapp start
and rebar.config
{deps, [
{bitcask, ".*", {git, "git://github.com/basho/bitcask.git", "master"}}
]}.
Getting the dependencies works, but compiling fails.
The verbose output tells me that this command fails
cmd: cc -c $CFLAGS -g -Wall -fPIC -I"/usr/lib/erlang/lib/erl_interface-3.7.18/include" -I"/usr/lib/erlang/erts-6.2/include" c_src/bitcask_nifs.c -o c_src/bitcask_nifs.o
with this error
/home/user/folder/deps/bitcask/c_src/bitcask_nifs.c:22:19: fatal error: errno.h: No such file or directory
But
find /usr/include -name errno.h
gives me
/usr/include/x86_64-linux-gnu/asm/errno.h
/usr/include/asm/errno.h
/usr/include/linux/errno.h
/usr/include/asm-generic/errno.h
So I was asking myself..
what am I missing?
how can I tell rebar about the depencies on the C libraries and where to find them?
why isn't this configured correctly in the Makefile of bitcask?
Maybe I was searching for the wrong terms, but I couldn't find any solution in the internets.
Many thanks in advance
There are two thing to consider
rebar options
You can set options for compiling C code with port_env option in rebar.config.
comiling deps
Since bitstack is your dependency, it is not compiled with yours rebar config, but with it's own. So if you would like to change anything, you would have to modify the bitcask file.
Fortunately, if you look into config their writen all C compilation is done with environment variable $ERL_CFLAGS. And again, in rebar source code you can see that this flag is responsible for include paths in your compilation.
So easist way would be extending $ERL_CFLAGS in your Makefile before compilation, with something like this
all: ERL_CFLAGS = "$ERL_CFLAGS -I /usr/include/linux/errno.h"
all:
test -d deps || rebar get-deps
rebar compile -v
#erl -noshell -pa './deps/bitcask/ebin' -pa './ebin' -s myapp start
Just make sure that this include works for you, and that you are not overwriting any flags you are using.

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