Adding new runtime library

Adding new runtime library

[Petros Panayi]

Hi,
I try to write an optimization pass which at some point will make a call 
to a  new runtime library.
To achieve this I need to write my own runtime library i.e something 
like libgomp but much simpler for now.
I will like to know if there is a tutorial of any documentation on how 
to do this?
If not can you enumerate which files I have to modify to achieve it?
Thanks in advance.
Petros

Re: Adding new runtime library

[Basile STARYNKEVITCH]

Petros Panayi wrote:
> Hi,
> I try to write an optimization pass which at some point will make a 
> call to a  new runtime library.
> To achieve this I need to write my own runtime library i.e something 
> like libgomp but much simpler for now.
> I will like to know if there is a tutorial of any documentation on how 
> to do this?


With the new plugin mechanism in the trunk it should be even simpler 
(basically, link your libary into your plugin or extend your library to 
make it a GCC plugin).

However, even without plugins, it is not that hard.

The easy part is to change the gcc/Makefile.in - you might consider 
looking into the MELT branch 
http://gcc.gnu.org/viewcvs/branches/melt-branch/gcc/Makefile.in (which 
adds some additional libraries into cc1). You probably should add stuff 
into the BACKENDLIBS= make variable (not far from line 923 in 
gcc/Makefile.in in the trunk)

The less easy part (which you might consider optional) would be to hack 
the gcc/configure.ac file to test the availability of your additional 
library. You may also want to add a --with-XXX argument to configure... 
and be able to set your libraries header files and linkable archive 
paths (ie the -I or -L arguments needed).

The hardest part is indeed to write an optimisation pass :-)

Regards.

-- 
Basile STARYNKEVITCH         http://starynkevitch.net/Basile/
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Adding a new Struct (RECORD_TYPE)

[Petros Panayi]

Hi,
I try to create and populate a new struct into my the generated code. 
Something like:
struct ddm_temaplate{
    int loop_interations;
    int ddm_thread_num;
};

What I have up to now is the following:

static tree build_ddm_template_struct() {
    tree type = lang_hooks.types.make_type(RECORD_TYPE);
    tree id, field, fields;
    id = get_identifier("loop_interations");
    fields = build_decl (FIELD_DECL,id, integer_type_node);
    id = get_identifier("ddm_thread_num");
    field = build_decl (FIELD_DECL, id, integer_type_node);
    TREE_CHAIN (field) = fields;
    fields = field;
    finish_builtin_struct(type, "__ddm_template", fields, NULL_TREE);
    return type;

}

/* After this call I get somthing like struct __ddm_template 
.ddm_template_instance.38; ...*/
static tree build_struct_instance(tree type) {
    tree arg_struct_instance, var;
    arg_struct_instance = create_tmp_var(type, ".ddm_template_instance");
    return arg_struct_instance;
}

and I use them as

    type = build_ddm_template_struct();
    struct_instance = build_struct_instance(type);
   
    fields = TYPE_FIELDS (type);
    t = build3(COMPONENT_REF, type, struct_instance, fields, NULL_TREE);
    tree astmt = build_gimple_modify_stmt(t,build_int_cstu 
(lang_hooks.types.type_for_size (32, true),99));
    print_generic_stmt(stderr, astmt,0); /* Here i get something like 
.ddm_template_instance.38.loop_interations = 99; */
    bsi_insert_after(&si, astmt, BSI_NEW_STMT);

This code will create an error when verify_loop_closed_ssa() is called.
I believe the problem is that loop_interations field does not get an SSA 
name.

Can anyone help me fixing this problem.
Thanks in advance
Petros