CFLAGS variation for modules in makefile

Question

I'm working on a large firmware and I've to add GNU gprof to only some modules(file directories) of it. The makefiles have inherited structure. So I do it this way:

ft/*.o : ft/*.c
       CFLAGS += -pg
ft/*.o : ft/*.c
       LDFLAGS += -pg

But this gives me a warning that it will overwrite the CFLAGS and then it adds the gprof to all the modules. My guess is that CFLAG is somewhere common. How can I make sure that CFLAG only works on the part of module(directory) I want on?

score 2 · Answer 1 · answered Mar 22 '16 at 14:28

2

You can do it using target-specific variables.

The correct syntax is:

ft/*.o : CFLAGS += -pg
ft/*.o : LDFLAGS += -pg

These are the lines you need to add.

Alternatively, you can add these flags to executables, shared and static libraries. Target specific variables propagate to its prerequisites, i.e. the .o files comprising your binaries.

answered Mar 22 '16 at 14:28

Maxim Egorushkin

131,725
17
180
271

This wouldn't work for some reason and i'm not sure how to debug it. Is there any other way to get the file make is currently building and then apply CFLAGS over it? – user131274 Mar 23 '16 at 11:55
@user131274 Try `make -d` to and `make -p`. – Maxim Egorushkin Mar 23 '16 at 11:56

CFLAGS variation for modules in makefile

1 Answers1