Is there incremental linker for linux?

jaristr · 03-07-2006, 09:12 AM

Hello,
I have been using GCC to compile in linux but compiling large projects takes time because as far as I know the linking isnt incremental, is this correct?
Is there any way to build faster in linux?

Thank you.

Jari.

aluser · 03-07-2006, 11:51 AM

ld does support incremental linking, but I wonder if that's actually the question you mean to ask. Are you using a Makefile? If not, you probably should be.

The link step usually doesn't take very long. If you're sure that it's the *link* that's taking a long time and not the compile, then ignore this post : )

nx5000 · 03-07-2006, 11:54 AM

Make should handle incremental build . For incremental link there is an option in gcc but I have no clue how it works.
To speedup compiles, try
ccache
and
distcc if you have a cluster of machines

jaristr · 03-07-2006, 02:09 PM

Sorry, you are right, I was supposed to say that linking (not compiling) takes time with larger projects.

aluser · 03-07-2006, 03:03 PM

Ok, according to the ld man page you use -i, and it seems to work about as one would expect. Here I have 5 .c files: a.c, b.c, c.c, d.c, and main.c. I compile them all into *.o object files, then incrementally link a.o and b.o into ab.o, and I link c.o and d.o into cd.o. Finally, I link ab.o, cd.o, and main.o into a finished executable named "thing":

Code:

15:59 aluser@alf:~/test/c/incremental$ cat Makefile
thing: ab.o cd.o main.o
        $(CC) -o $@ $^
ab.o: a.o b.o
cd.o: c.o d.o
ab.o cd.o:
        $(LD) -i -o $@ $^
16:00 aluser@alf:~/test/c/incremental$ ls
Makefile  a.c  b.c  c.c  d.c  main.c
16:02 aluser@alf:~/test/c/incremental$ make
cc    -c -o a.o a.c
cc    -c -o b.o b.c
ld -i -o ab.o a.o b.o
cc    -c -o c.o c.c
cc    -c -o d.o d.c
ld -i -o cd.o c.o d.o
cc    -c -o main.o main.c
cc -o thing ab.o cd.o main.o
16:02 aluser@alf:~/test/c/incremental$ ./thing
Hello, world

jaristr · 03-09-2006, 02:28 PM

aluser, thank you!
That looks like a great solution, I wonder how hard it's going to be to get that working in KDevelop or in anjuta.

jaristr · 03-11-2006, 01:09 PM

I have been trying to figure out how to compile C++ files but it looks like that while I can create the object (.o) files with g++ (using -c option) I cannot link them with ld.

So is ld only for C linking?

Thank you.

Jari.

aluser · 03-11-2006, 01:18 PM

Quote:

So is ld only for C linking?

Hm my guess is that it needs extra options to do c++.. Have you tried using g++ with -Wl,-i ?

jaristr · 03-11-2006, 02:02 PM

Quote:

Originally Posted by aluser

Hm my guess is that it needs extra options to do c++.. Have you tried using g++ with -Wl,-i ?

You are right the -i was what was needed. So I got it working now, just strange that the --help didnt mention it... and man page merely said it could be used.

Well anyway, thanks for the help, again!