> 2014-09-27 Ilya Verbin <ilya.ver...@intel.com>
> Ilya Tocar <ilya.to...@intel.com>
> Andrey Turetskiy <andrey.turets...@intel.com>
> Bernd Schmidt <ber...@codesourcery.com>
> gcc/
> * cgraph.h (symtab_node): Add need_dump flag.
> * cgraphunit.c: Include lto-section-names.h.
> (initialize_offload): New function.
> (ipa_passes): Initialize offload and call ipa_write_summaries if there
> is something to write to OMP_SECTION_NAME_PREFIX sections.
> (symbol_table::compile): Call lto_streamer_hooks_init under flag_openmp.
> * ipa-inline-analysis.c (inline_generate_summary): Do not exit under
> flag_openmp.
> (inline_free_summary): Always remove hooks.
> * lto-cgraph.c (lto_set_symtab_encoder_in_partition): Exit if there is
> no need to encode the node.
> (referenced_from_other_partition_p, reachable_from_other_partition_p):
> Ignore references from non-target functions to target functions if we
> are streaming out target-side bytecode (offload lto mode).
> (select_what_to_dump): New function.
> * lto-section-names.h (OMP_SECTION_NAME_PREFIX): Define.
> (section_name_prefix): Declare.
> * lto-streamer.c (offload_lto_mode): New variable.
> (section_name_prefix): New variable.
> (lto_get_section_name): Use section_name_prefix instead of
> LTO_SECTION_NAME_PREFIX.
> * lto-streamer.h (select_what_to_dump): Declare.
> (offload_lto_mode): Declare.
> * omp-low.c (is_targetreg_ctx): New function.
> (create_omp_child_function, check_omp_nesting_restrictions): Use it.
> (expand_omp_target): Set mark_force_output for the target functions.
> (lower_omp_critical): Add target attribute for omp critical symbol.
> * passes.c (ipa_write_summaries): Call select_what_to_dump.
> gcc/lto/
> * lto-object.c (lto_obj_add_section): Use section_name_prefix instead of
> LTO_SECTION_NAME_PREFIX.
> * lto-partition.c (add_symbol_to_partition_1): Always set
> node->need_dump to true.
> (lto_promote_cross_file_statics): Call select_what_to_dump.
> * lto.c (lto_section_with_id): Use section_name_prefix instead of
> LTO_SECTION_NAME_PREFIX.
> (read_cgraph_and_symbols): Read OMP_SECTION_NAME_PREFIX sections, if
> being built as an offload compiler.
>
> Thanks,
> -- Ilya
>
> ---
>
> diff --git a/gcc/cgraph.h b/gcc/cgraph.h
> index 7481906..9ab970d 100644
> --- a/gcc/cgraph.h
> +++ b/gcc/cgraph.h
> @@ -444,6 +444,11 @@ public:
> /* Set when init priority is set. */
> unsigned in_init_priority_hash : 1;
>
> + /* Set when symbol needs to be dumped into LTO bytecode for LTO,
> + or in pragma omp target case, for separate compilation targeting
> + a different architecture. */
> + unsigned need_dump : 1;
dump for me implied debug dump. LTO is usually called streaming, so prehaps
need_lto_stremaing?
> +/* Check whether there is at least one function or global variable to
> offload.
> + */
> +
> +static bool
> +initialize_offload (void)
Perhaps have_offload_p? Nothing is initialized here...
> +{
> + bool have_offload = false;
> + struct cgraph_node *node;
> + struct varpool_node *vnode;
> +
> + FOR_EACH_DEFINED_FUNCTION (node)
> + if (lookup_attribute ("omp declare target", DECL_ATTRIBUTES
> (node->decl)))
> + {
> + have_offload = true;
> + break;
> + }
> +
> + FOR_EACH_DEFINED_VARIABLE (vnode)
> + {
> + if (!lookup_attribute ("omp declare target",
> + DECL_ATTRIBUTES (vnode->decl))
> + || TREE_CODE (vnode->decl) != VAR_DECL
> + || DECL_SIZE (vnode->decl) == 0)
> + continue;
> + have_offload = true;
> + }
> +
> + return have_offload;
> +}
> +
> static void
> ipa_passes (void)
> {
> + bool have_offload = false;
> gcc::pass_manager *passes = g->get_passes ();
>
> set_cfun (NULL);
> @@ -2004,6 +2036,14 @@ ipa_passes (void)
> gimple_register_cfg_hooks ();
> bitmap_obstack_initialize (NULL);
>
> + if (!in_lto_p && flag_openmp)
> + {
> + have_offload = initialize_offload ();
> + /* OpenMP offloading requires LTO infrastructure. */
> + if (have_offload)
> + flag_generate_lto = 1;
> + }
> +
> invoke_plugin_callbacks (PLUGIN_ALL_IPA_PASSES_START, NULL);
>
> if (!in_lto_p)
> @@ -2041,7 +2081,20 @@ ipa_passes (void)
> targetm.asm_out.lto_start ();
>
> if (!in_lto_p)
> - ipa_write_summaries ();
> + {
> + if (have_offload)
> + {
> + offload_lto_mode = true;
> + section_name_prefix = OMP_SECTION_NAME_PREFIX;
> + ipa_write_summaries ();
> + }
> + if (flag_lto)
> + {
> + offload_lto_mode = false;
> + section_name_prefix = LTO_SECTION_NAME_PREFIX;
> + ipa_write_summaries ();
> + }
How does LTO combine with offloading?
> @@ -4325,11 +4325,6 @@ void
> inline_free_summary (void)
> {
> struct cgraph_node *node;
> - if (!inline_edge_summary_vec.exists ())
> - return;
> - FOR_EACH_DEFINED_FUNCTION (node)
> - if (!node->alias)
> - reset_inline_summary (node);
> if (function_insertion_hook_holder)
> symtab->remove_cgraph_insertion_hook (function_insertion_hook_holder);
> function_insertion_hook_holder = NULL;
> @@ -4345,6 +4340,11 @@ inline_free_summary (void)
> if (edge_duplication_hook_holder)
> symtab->remove_edge_duplication_hook (edge_duplication_hook_holder);
> edge_duplication_hook_holder = NULL;
> + if (!inline_edge_summary_vec.exists ())
> + return;
> + FOR_EACH_DEFINED_FUNCTION (node)
> + if (!node->alias)
> + reset_inline_summary (node);
Why this is needed?
> diff --git a/gcc/lto-cgraph.c b/gcc/lto-cgraph.c
> index 0584946..78b7fc8 100644
> --- a/gcc/lto-cgraph.c
> +++ b/gcc/lto-cgraph.c
> @@ -239,6 +239,9 @@ void
> lto_set_symtab_encoder_in_partition (lto_symtab_encoder_t encoder,
> symtab_node *node)
> {
> + /* Ignore not needed nodes. */
> + if (!node->need_dump)
> + return;
I think it should be rather done at caller side (in the loop setting what to
output)
rather than in this simple datastructure accestor.
> int index = lto_symtab_encoder_encode (encoder, node);
> encoder->nodes[index].in_partition = true;
> }
> @@ -321,6 +324,12 @@ referenced_from_other_partition_p (symtab_node *node,
> lto_symtab_encoder_t encod
>
> for (i = 0; node->iterate_referring (i, ref); i++)
> {
> + /* Ignore references from non-target functions in offload lto mode. */
> + if (offload_lto_mode
> + && !lookup_attribute ("omp declare target",
> + DECL_ATTRIBUTES (ref->referring->decl)))
> + continue;
Those are quite busy loops, you may consder making offload a flag. Why you
can't test
need_dump here?
I think you also need to run free lang data when you decide to stream something.
Otherwise the cgraph bits seems resonable. I think Richi will want to comment
on LTO
part.
Honza
