Make: extract the target path segment that follows a known one - makefile

Question

I am trying to optimize our build targets. In our current process we have separate targets for 32bit & 64bit build. Due to separate targets we have hundreds of targets in our build flow. Where we try to make it global i.e. one target for both 32-bit and 64-bit build. I'm trying to achieve this with the code below.
Target/Output directory for 32-bit build should be like:
/test/scratch/<client_name>/Linux/...
Target/Output directory for 64-bit build should be like:
/test/scratch/<client_name>/Linux-64bit/...
So based on above Target directory paths I am searching the string Linux using $(findstring) function and proceed with 32-bit command to run. Else it will run 64bit command as shown below.
RELEASE_FILES := $(TARGET_DIR)/build/test/csimtime.c
$(RELEASE_FILES): $(TGTDIRFILES)/%: %
ifneq (Linux,$(findstring $(OS),$#))
$(test_lib_32)
else
$(test_lib_64)
endif
$(TARGET_DIR) variable is passed as parameter to make command
make TARGET_DIR=$(TGT32) all32
For 64-bit we will pass TARGET_DIR=$(TGT64) instead.
Note: test_lib_32/64 above are macro definition in other make file which we are including in current make file.
It works fine as expected, But I am not sure whether this is the best way? And I notice one problem here, Generally TGT32/TGT64 variable which we are passing has values either:
/test/scratch/<client_name>/Linux/ (for 32bit)
or
/test/scratch/<client_name>/Linux-64bit/... (for 64bit)
If someone creates a client with client_name 'Linux' string it wont work. It will always go to if block and try to run 32-bit command even when we run 64-bit build. How can I handle this?
I am looking for getting the string after 'client_name' in above path.. Could please help?

Answer 1

If your target directory name is always something like:
/test/scratch/<client_name>/Linux/...
and there is no / character and no spaces in <client-name>, you can base your test on the exact position of Linux (or Linux-64bit) in the path:
TYPE := $(word 4,$(subst /, ,$(TARGET_DIR)))
ifeq ($(TYPE),Linux)
<something>
else ifeq ($(TYPE),Linux-64bit)
<something-else>
else
$(error Unknown type: $(TYPE))
endif
EDIT if the position is not constant but you know what <client-name> is, and there is no / character and no spaces in <client-name>, you can extract the name of the directory that follows <client-name> in $(TARGET_DIR) like this:
TAIL := $(subst /, ,$(TARGET_DIR))
$(foreach w,$(TAIL),$(eval TAIL := $(wordlist 2,$(words $(TAIL)),$(TAIL)))$(if $(patsubst $(CLIENT_NAME),,$(w)),,$(eval TYPE := $(word 1,$(TAIL)))))
all:
#printf 'TYPE = $(TYPE)\n'
Demo:
$ make TARGET_DIR=/a/b/test-client/Linux/c/d CLIENT_NAME=test-client
TYPE = Linux
$ make TARGET_DIR=/a/b/c/d/test-client/Linux-64bit/e/f/g CLIENT_NAME=test-client
TYPE = Linux-64bit
Explanation:
TAIL := $(subst /, ,$(TARGET_DIR)) replaces the / characters in $(TARGET_DIR) by one space, such that it becomes a list of words (one per directory in the path), and assigns the result to variable TAIL.
$(foreach w,$(TAIL),...) evaluates ... with variable w set successively to each word of $(TAIL).
$(eval TAIL := $(wordlist 2,$(words $(TAIL)),$(TAIL))) re-assigns variable TAIL by removing the leading word.
$(if $(patsubst $(CLIENT_NAME),,$(w)),,...) evaluates ... if $(w) equals $(CLIENT_NAME).
$(eval TYPE := $(word 1,$(TAIL))) assigns the first word of $(TAIL) to variable TYPE.
There may be simpler ways to do the same...

Answer 2

If I understand your question correctly then you get problems with the following $(TARGET_DIR) value:
/.../Linux/.../Linux-64bit
The problem is that you are testing on the value of $#:
/.../Linux/.../Linux-64bit/some/other/file
As you can see that makes it impossible to decide which Linux in the path should be used for the decision.
I would suggest to try this instead:
# if $(TARGET_DIR) ends with /Linux -> 32-bit build
$(RELEASE_FILES): $(TGTDIRFILES)/%: %
ifneq ($(filter %/Linux,$(TARGET_DIR)),)
$(test_lib_32)
else
$(test_lib_64)
endif