Index

1. Using GNU Automake with gm2

• gm2 (from gcc-14 onwards) supports -M , -MM , -MD , -MMD , -MP , -MT and -MQ https://gcc.gnu.org/onlinedocs/gcc/Preprocessor-Options.html
• -M and -MM are run without generating any code (in the preprocessor stage).
• -MD , -MMD are run with the compiler and therefore the command line can generate dependencies and also code.
  • the example project here uses -MMD as one command line can be used to generate an object file and a dependency file.

2. Example project

• the example project m2-autoconf-example is available via:

• $ git clone https://github.com/gaiusm/m2-autoconf-example

• consists of a tiny example modula-2 project containing modules:
  • top.mod the application level module
  • z.def and z.mod the lowest level module exporting zproc
  • module a.def and a.mod (also imports module z )
  • module b.def and b.mod
  • module a.def and a.mod (also imports module z )
    

3. configure and compile project

• $ mkdir build-m2-autoconf-example
  $ cd build-m2-autoconf-example
  $ ../m2-autoconf-example/configure
  $ make

  gm2 -MMD -MT a.o -MP -MF .deps/a.d  -I../m2-autoconf-example \
      -c ../m2-autoconf-example/a.mod
  gm2 -MMD -MT b.o -MP -MF .deps/b.d  -I../m2-autoconf-example \
      -c ../m2-autoconf-example/b.mod
  gm2 -MMD -MT c.o -MP -MF .deps/c.d  -I../m2-autoconf-example \
      -c ../m2-autoconf-example/c.mod
  gm2 -MMD -MT z.o -MP -MF .deps/z.d  -I../m2-autoconf-example \
      -c ../m2-autoconf-example/z.mod
  gm2 -MMD -MT top.o -MP -MF .deps/top.d  -I../m2-autoconf-example \
      -c -fscaffold-main -fscaffold-dynamic \
      ../m2-autoconf-example/top.mod
  gm2 a.o b.o c.o z.o top.o -o top

• modules: a , b , c , z are all compiled using the same rule.
• module top is compiled to include the C function main and also the runtime scaffold to initialize all modules.
  • but the rule does not perform the link
• the final gm2 command links and place the executable into top
• on inspection we can see that the dependencies for module c are stored in file .deps/c.d with contents:

• c.o: \
   ../m2-autoconf-example/c.mod \
   ../m2-autoconf-example/c.def \
   ../m2-autoconf-example/z.def

4. Makefile.am

• SUFFIXES = .mod .def .o .a
  
  DEPFLAGS=-MMD -MT $@ -MP -MF .deps/$*.d
  
  DEPS = a.o \
         b.o \
         c.o \
         z.o \
         top.o
  
  
  bin_PROGRAMS = top
  top_SOURCES = top.mod \
         a.mod \
         b.mod \
         c.mod \
         z.mod

• top$(EXEEXT): $(DEPS)
       gm2 $(DEPS) -o $@
  
  
  top.o: top.mod
       gm2 $(DEPFLAGS) -I$(srcdir) -c \
           -fscaffold-main -fscaffold-dynamic $<
  
  
  %.o: %.mod .deps/%.d
       @test -z .deps || mkdir -p .deps
       gm2 $(DEPFLAGS) -I$(srcdir) -c $<

• DEPFILES=$(top_SOURCES:%.mod=.deps/%.d)
  
  $(DEPFILES):
  
  include $(wildcard $(DEPFILES))

5. rundemo

• the script rundemo runs make then modifies module z to export procedure bar . It also modifies module c to call bar
  • make is run again which results in a recompile of modules: a , c and z . It then links all modules

• $ bash rundemo

  gm2 -MMD -MT a.o -MP -MF .deps/a.d -I../m2-autoconf-example \
      -c ../m2-autoconf-example/a.mod
  gm2 -MMD -MT c.o -MP -MF .deps/c.d -I../m2-autoconf-example \
      -c ../m2-autoconf-example/c.mod
  gm2 -MMD -MT z.o -MP -MF .deps/z.d -I../m2-autoconf-example \
      -c ../m2-autoconf-example/z.mod
  gm2 a.o b.o c.o z.o top.o -o top

Index

This document was produced using groff-1.22.