Hello,
just trying one more time. Any direction or hint is appreciated. Just
as a note, I looked at the ipa-devirt as an inspiration for these
small functions I wrote, but for some reason I can't read what I
assume have written to the summaries. (What I'm trying to do is simply
use LTO using a real IPA_PASS as opposed to SIMPLE_IPA_PASS, and
therefore I just want to write some simple summaries and read them).
I have wondered if the bitpack_d bp = bitpack_create
(ob->main_stream); creates any difference, but when I tried it that
didn't seem to be the case.
Many thanks in advance!
On Tue, 30 Mar 2021 at 10:18, Erick Ochoa <eoc...@gcc.gnu.org> wrote:
>
> Hello,
>
> just trying again to increase visibility of this question. Many thanks
> in advance!
>
>
> On Fri, 26 Mar 2021 at 13:49, Erick Ochoa <eoc...@gcc.gnu.org> wrote:
> >
> > Hello,
> >
> > I already have some experience developing SIMPLE_IPA_PASSes, but I am
> > looking to understand IPA_PASSes better. I have made a hello world ipa
> > pass that stores "hello world $FUNCTION_NAME" in the function
> > summaries; however, I am having trouble reading this information back.
> > Can someone help me understand how to use these interfaces correctly?
> >
> > At the moment, it **seems** to be writing information correctly.
> > (I.e., it doesn't segfault when attempting to write data.) However, in
> > my read summary function (ipa_hello_world_read_summary (void)) the
> > function `lto_get_summary_section_data (file_data,
> > LTO_section_ipa_hello_world, &len);` always returns NULL and
> > `file_data_vec` is of size 1. This means that at run time, there is
> > only one call to `lto_get_summary_section_data` and it returns NULL.
> >
> > I am copy-pasting the relevant code below.
> >
> > /* Map from cgraph_node* to "hello world $FUNCTION_NAME". */
> > static hash_map<cgraph_node*, char*> *hello_summaries;
> >
> > static void
> > ipa_hello_world_write_summary (void)
> > {
> > gcc_assert(hello_summaries);
> > struct output_block *ob = create_output_block
> > (LTO_section_ipa_hello_world);
> > gcc_assert(ob);
> > if (dump_file) fprintf(dump_file, "hello world from write summary\n");
> > lto_symtab_encoder_t encoder = ob->decl_state->symtab_node_encoder;
> > if (dump_file) fprintf(dump_file, "writing %d\n",
> > hello_summaries->elements());
> > streamer_write_uhwi (ob, hello_summaries->elements());
> >
> > for (auto i = hello_summaries->begin(), e = hello_summaries->end();
> > i != e; ++i)
> > {
> > if (dump_file) fprintf(dump_file, "writing %s\n", (*i).second);
> > streamer_write_uhwi(ob, lto_symtab_encoder_encode(encoder, (*i).first));
> > streamer_write_string (ob, ob->main_stream, (*i).second, true);
> > }
> > produce_asm (ob, NULL);
> > destroy_output_block (ob);
> > delete hello_summaries;
> > }
> >
> > static void
> > ipa_hello_world_read_summary (void)
> > {
> > struct lto_file_decl_data **file_data_vec = lto_get_file_decl_data ();
> > struct lto_file_decl_data *file_data;
> > unsigned int j = 0;
> > if (dump_file) fprintf(dump_file, "hello from read summary\n");
> > while ((file_data = file_data_vec[j++]))
> > {
> > if (dump_file) fprintf(dump_file, "iteration = %d\n", j);
> > size_t len;
> > const char *data =
> > lto_get_summary_section_data (file_data,
> > LTO_section_ipa_hello_world, &len);
> > if (!data) continue;
> >
> > const struct lto_function_header *header = (const struct
> > lto_function_header*) data;
> > gcc_assert(header);
> > gcc_assert(header->cfg_size);
> > const int cfg_offset = sizeof (struct lto_function_header);
> > const int main_offset = cfg_offset + header->cfg_size;
> > const int string_offset = main_offset + header->main_size;
> > class data_in *data_in;
> >
> > lto_input_block ib ((const char *) data + main_offset,
> > header->main_size,
> > file_data->mode_table);
> > data_in
> > = lto_data_in_create (file_data, (const char *) data + string_offset,
> > header->string_size, vNULL);
> > unsigned int n = streamer_read_uhwi (&ib);
> > //hello_summaries = new hash_map<cgraph_node*, char*>;
> > for (unsigned i = 0; i < n; i++)
> > {
> > unsigned int index = streamer_read_uhwi(&ib);
> > lto_symtab_encoder_t encoder = file_data->symtab_node_encoder;
> > struct cgraph_node *cnode = dyn_cast<cgraph_node *>
> > (lto_symtab_encoder_deref(encoder, index));
> > gcc_assert(cnode);
> > const char* string = streamer_read_string (data_in, &ib);
> > if (dump_file) fprintf(dump_file, string);
> > }
> > }
> >
> > }
