[CMake] Fix dependencies for generating mem_initializer.cpp.

Previously CMake was not aware of which headers files the generation
of `mem_initializer.cpp` depended on. Consequently this could result
in broken incremental builds if

* Existing headers that declare memory initializers/finalizers change.
* New headers are added that declare memory initializers/finalizer.

Now the `z3_add_component()` CMake function has been modifed so that
it now takes an optional `MEMORY_INIT_FINALIZER_HEADERS` argument
which allows the headers that declare memory initializers/finalizers
to be explicitly listed.

With this information CMake will now regenerate `mem_initializer.cpp`
correctly.

This required the `mk_mem_initializer_cpp_internal()` function to be
changed to take a list of header files rather than a list of component
source directories. The two consumers (CMake and Python/Makefile build
systems) of this function have been modified to work with this change.

This partially fixes #1030.

scripts/mk_genfile_common.py

@@ -731,7 +731,7 @@ def mk_install_tactic_cpp_internal(h_files_full_path, path):
 # Functions for generating ``mem_initializer.cpp``
 ###############################################################################
 
-def mk_mem_initializer_cpp_internal(component_src_dirs, path):
+def mk_mem_initializer_cpp_internal(h_files_full_path, path):
     """
         Generate a ``mem_initializer.cpp`` file in the directory ``path``.
         Returns the path to the generated file.
@@ -745,7 +745,7 @@ def mk_mem_initializer_cpp_internal(component_src_dirs, path):
 
        These procedures are invoked by the Z3 memory_manager
     """
-    assert isinstance(component_src_dirs, list)
+    assert isinstance(h_files_full_path, list)
     assert check_dir_exists(path)
     initializer_cmds = []
     finalizer_cmds   = []
@@ -756,11 +756,6 @@ def mk_mem_initializer_cpp_internal(component_src_dirs, path):
     # ADD_INITIALIZER with priority
     initializer_prio_pat = re.compile('[ \t]*ADD_INITIALIZER\(\'([^\']*)\',[ \t]*(-?[0-9]*)\)')
     finalizer_pat        = re.compile('[ \t]*ADD_FINALIZER\(\'([^\']*)\'\)')
-    h_files_full_path = []
-    for component_src_dir in sorted(component_src_dirs):
-        h_files = filter(lambda f: f.endswith('.h') or f.endswith('.hpp'), os.listdir(component_src_dir))
-        h_files = list(map(lambda p: os.path.join(component_src_dir, p), h_files))
-        h_files_full_path.extend(h_files)
     for h_file in sorted_headers_by_component(h_files_full_path):
         added_include = False
         with open(h_file, 'r') as fin:

scripts/mk_mem_initializer_cpp.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 """
-Scans the source directories for
+Scans the listed header files for
 memory initializers and finalizers and
 emits and implementation of
 ``void mem_initialize()`` and
@@ -17,19 +17,19 @@ def main(args):
     logging.basicConfig(level=logging.INFO)
     parser = argparse.ArgumentParser(description=__doc__)
     parser.add_argument("destination_dir", help="destination directory")
-    parser.add_argument("source_dirs", nargs="+",
-                        help="One or more source directories to search")
+    parser.add_argument("header_files", nargs="+",
+                        help="One or more header files to parse")
     pargs = parser.parse_args(args)
 
     if not mk_genfile_common.check_dir_exists(pargs.destination_dir):
         return 1
 
-    for source_dir in pargs.source_dirs:
-        if not mk_genfile_common.check_dir_exists(source_dir):
-            return 1
+    h_files_full_path = []
+    for header_file in pargs.header_files:
+        h_files_full_path.append(os.path.abspath(header_file))
 
     output = mk_genfile_common.mk_mem_initializer_cpp_internal(
-        pargs.source_dirs,
+        h_files_full_path,
         pargs.destination_dir
     )
     logging.info('Generated "{}"'.format(output))

scripts/mk_util.py

@@ -2745,7 +2745,8 @@ def mk_mem_initializer_cpp(cnames, path):
     for cname in cnames:
         c = get_component(cname)
         component_src_dirs.append(c.src_dir)
-    generated_file = mk_genfile_common.mk_mem_initializer_cpp_internal(component_src_dirs, path)
+    h_files_full_path = get_header_files_for_components(component_src_dirs)
+    generated_file = mk_genfile_common.mk_mem_initializer_cpp_internal(h_files_full_path, path)
     if VERBOSE:
         print("Generated '{}'".format(generated_file))