On Wed, 1 Oct 2014, Ilya Verbin wrote:
> On 30 Sep 13:40, Thomas Schwinge wrote:
> > As just discussed for the libgcc changes in
> > <http://news.gmane.org/find-root.php?message_id=%3C87d2ad73ze.fsf%40schwinge.name%3E>,
> > just some suggestions regarding the terminology, where I think that the
> > term »target« might be confusing in comments or symbols' names. That is,
> > in the following, »target« should possibly be replaced by »offload[ing]«
> > or similar:
> >
> > What about:
> >
> > #define OFFLOAD_SECTION_NAME_PREFIX ".gnu.offload_lto_"
>
> Renamed, patch is updated.
>
> Thanks,
> -- Ilya
>
>
> gcc/
> * cgraph.h (symtab_node): Add need_lto_streaming 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 OFFLOAD_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 (referenced_from_other_partition_p): Ignore references
> from non-offloadable nodes while streaming a node into offload section.
> (reachable_from_other_partition_p): Likewise.
> (select_what_to_stream): New function.
> (compute_ltrans_boundary): Do not call
> lto_set_symtab_encoder_in_partition if the node should not be streamed.
> * lto-section-names.h (OFFLOAD_SECTION_NAME_PREFIX): Define.
> (section_name_prefix): Declare.
> * lto-streamer.c (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_stream): 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 offloaded functions.
> (lower_omp_critical): Add target attribute for omp critical symbol.
> * passes.c (ipa_write_summaries): New argument offload_lto_mode. Call
> select_what_to_stream. Do not call lto_set_symtab_encoder_in_partition
> if the node should not be streamed out.
> * tree-pass.h (ipa_write_summaries): New bool argument.
> gcc/lto/
> * lto-object.c (lto_obj_add_section): Use section_name_prefix instead of
> LTO_SECTION_NAME_PREFIX.
> * lto-partition.c (lto_promote_cross_file_statics): Call
> select_what_to_stream.
> * lto.c (lto_section_with_id): Use section_name_prefix instead of
> LTO_SECTION_NAME_PREFIX.
> (read_cgraph_and_symbols): Read OFFLOAD_SECTION_NAME_PREFIX sections, if
> being built as an offload compiler.
>
> ---
>
> diff --git a/gcc/cgraph.h b/gcc/cgraph.h
> index 4fd58a5..df0b0e2 100644
> --- a/gcc/cgraph.h
> +++ b/gcc/cgraph.h
> @@ -444,6 +444,10 @@ public:
> /* Set when init priority is set. */
> unsigned in_init_priority_hash : 1;
>
> + /* Set when symbol needs to be streamed into LTO bytecode for LTO, or in
> case
> + of offloading, for separate compilation for a different target. */
> + unsigned need_lto_streaming : 1;
> +
>
> /* Ordering of all symtab entries. */
> int order;
> diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
> index d463505..5eb9d64 100644
> --- a/gcc/cgraphunit.c
> +++ b/gcc/cgraphunit.c
> @@ -211,6 +211,7 @@ along with GCC; see the file COPYING3. If not see
> #include "tree-nested.h"
> #include "gimplify.h"
> #include "dbgcnt.h"
> +#include "lto-section-names.h"
>
> /* Queue of cgraph nodes scheduled to be added into cgraph. This is a
> secondary queue used during optimization to accommodate passes that
> @@ -1994,9 +1995,40 @@ output_in_order (bool no_reorder)
> free (nodes);
> }
>
> +/* Check whether there is at least one function or global variable to
> offload.
> + */
> +
> +static bool
> +initialize_offload (void)
> +{
> + 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;
> +}
> +
I wonder if we can avoid the above by means of a global have_offload
flag? (or inside gcc::context)
> 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)
As -fopenmp is not generally available it's odd to test
flag_openmp (though that is available everywhere as
implementation detail). Doesn't offloading work
without -fopenmp?
> + {
> + 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 +2081,18 @@ ipa_passes (void)
> targetm.asm_out.lto_start ();
>
> if (!in_lto_p)
> - ipa_write_summaries ();
> + {
> + if (have_offload)
> + {
> + section_name_prefix = OFFLOAD_SECTION_NAME_PREFIX;
> + ipa_write_summaries (true);
> + }
> + if (flag_lto)
> + {
> + section_name_prefix = LTO_SECTION_NAME_PREFIX;
> + ipa_write_summaries (false);
> + }
> + }
>
> if (flag_generate_lto)
> targetm.asm_out.lto_end ();
> @@ -2122,7 +2173,7 @@ symbol_table::compile (void)
> state = IPA;
>
> /* If LTO is enabled, initialize the streamer hooks needed by GIMPLE. */
> - if (flag_lto)
> + if (flag_lto || flag_openmp)
flag_generate_lto?
> lto_streamer_hooks_init ();
>
> /* Don't run the IPA passes if there was any error or sorry messages. */
> diff --git a/gcc/ipa-inline-analysis.c b/gcc/ipa-inline-analysis.c
> index 38f56d2..076a1e8 100644
> --- a/gcc/ipa-inline-analysis.c
> +++ b/gcc/ipa-inline-analysis.c
> @@ -4010,7 +4010,7 @@ inline_generate_summary (void)
>
> /* When not optimizing, do not bother to analyze. Inlining is still done
> because edge redirection needs to happen there. */
> - if (!optimize && !flag_lto && !flag_wpa)
> + if (!optimize && !flag_lto && !flag_wpa && !flag_openmp)
> return;
Likewise !flag_generate_lto
> function_insertion_hook_holder =
> @@ -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);
> vec_free (inline_summary_vec);
> inline_edge_summary_vec.release ();
> if (edge_predicate_pool)
> diff --git a/gcc/lto-cgraph.c b/gcc/lto-cgraph.c
> index 0584946..c1fccfa 100644
> --- a/gcc/lto-cgraph.c
> +++ b/gcc/lto-cgraph.c
> @@ -321,6 +321,11 @@ 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-offloadable nodes while streaming NODE
> into
> + offload LTO section. */
> + if (!ref->referring->need_lto_streaming)
> + continue;
> +
> if (ref->referring->in_other_partition
> || !lto_symtab_encoder_in_partition_p (encoder, ref->referring))
> return true;
> @@ -339,9 +344,16 @@ reachable_from_other_partition_p (struct cgraph_node
> *node, lto_symtab_encoder_t
> if (node->global.inlined_to)
> return false;
> for (e = node->callers; e; e = e->next_caller)
> - if (e->caller->in_other_partition
> - || !lto_symtab_encoder_in_partition_p (encoder, e->caller))
> - return true;
> + {
> + /* Ignore references from non-offloadable nodes while streaming NODE
> into
> + offload LTO section. */
> + if (!e->caller->need_lto_streaming)
> + continue;
> +
> + if (e->caller->in_other_partition
> + || !lto_symtab_encoder_in_partition_p (encoder, e->caller))
> + return true;
> + }
> return false;
> }
>
> @@ -802,6 +814,18 @@ create_references (lto_symtab_encoder_t encoder,
> symtab_node *node)
> lto_symtab_encoder_encode (encoder, ref->referred);
> }
>
> +/* Select what needs to be streamed out. In regular lto mode stream
> everything.
> + In offload lto mode stream only stuff marked with an attribute. */
> +void
> +select_what_to_stream (bool offload_lto_mode)
> +{
> + struct symtab_node *snode;
> + FOR_EACH_SYMBOL (snode)
> + snode->need_lto_streaming
> + = !offload_lto_mode || lookup_attribute ("omp declare target",
> + DECL_ATTRIBUTES (snode->decl));
I suppose I suggested this already earlier this year. Why keep this
artificial attribute when you have a cgraph node flag?
> +}
> +
> /* Find all symbols we want to stream into given partition and insert them
> to encoders.
>
> @@ -828,6 +852,8 @@ compute_ltrans_boundary (lto_symtab_encoder_t in_encoder)
> !lsei_end_p (lsei); lsei_next_function_in_partition (&lsei))
> {
> struct cgraph_node *node = lsei_cgraph_node (lsei);
> + if (!node->need_lto_streaming)
> + continue;
> add_node_to (encoder, node, true);
> lto_set_symtab_encoder_in_partition (encoder, node);
> create_references (encoder, node);
> @@ -844,6 +870,8 @@ compute_ltrans_boundary (lto_symtab_encoder_t in_encoder)
> {
> varpool_node *vnode = lsei_varpool_node (lsei);
>
> + if (!vnode->need_lto_streaming)
> + continue;
> lto_set_symtab_encoder_in_partition (encoder, vnode);
> lto_set_symtab_encoder_encode_initializer (encoder, vnode);
> create_references (encoder, vnode);
I leave all the partitioning stuff to Honza to review.
> diff --git a/gcc/lto-section-names.h b/gcc/lto-section-names.h
> index cb75230..f5dbed2 100644
> --- a/gcc/lto-section-names.h
> +++ b/gcc/lto-section-names.h
> @@ -25,6 +25,11 @@ along with GCC; see the file COPYING3. If not see
> name for the functions and static_initializers. For other types of
> sections a '.' and the section type are appended. */
> #define LTO_SECTION_NAME_PREFIX ".gnu.lto_"
> +#define OFFLOAD_SECTION_NAME_PREFIX ".gnu.offload_lto_"
> +
> +/* Can be either OFFLOAD_SECTION_NAME_PREFIX when we stream IR for offload
> + compiler, or LTO_SECTION_NAME_PREFIX for LTO case. */
> +extern const char *section_name_prefix;
>
> /* Segment name for LTO sections. This is only used for Mach-O. */
>
> diff --git a/gcc/lto-streamer.c b/gcc/lto-streamer.c
> index 3480723..161e12d 100644
> --- a/gcc/lto-streamer.c
> +++ b/gcc/lto-streamer.c
> @@ -48,6 +48,7 @@ struct lto_stats_d lto_stats;
> static bitmap_obstack lto_obstack;
> static bool lto_obstack_initialized;
>
> +const char *section_name_prefix = LTO_SECTION_NAME_PREFIX;
>
> /* Return a string representing LTO tag TAG. */
>
> @@ -177,7 +178,7 @@ lto_get_section_name (int section_type, const char *name,
> struct lto_file_decl_d
> sprintf (post, "." HOST_WIDE_INT_PRINT_HEX_PURE, f->id);
> else
> sprintf (post, "." HOST_WIDE_INT_PRINT_HEX_PURE, get_random_seed
> (false));
> - return concat (LTO_SECTION_NAME_PREFIX, sep, add, post, NULL);
> + return concat (section_name_prefix, sep, add, post, NULL);
> }
>
>
> diff --git a/gcc/lto-streamer.h b/gcc/lto-streamer.h
> index 4bec969..ba00ab4 100644
> --- a/gcc/lto-streamer.h
> +++ b/gcc/lto-streamer.h
> @@ -831,6 +831,7 @@ bool referenced_from_this_partition_p (symtab_node *,
> bool reachable_from_this_partition_p (struct cgraph_node *,
> lto_symtab_encoder_t);
> lto_symtab_encoder_t compute_ltrans_boundary (lto_symtab_encoder_t encoder);
> +void select_what_to_stream (bool);
>
>
> /* In lto-symtab.c. */
> diff --git a/gcc/lto/lto-object.c b/gcc/lto/lto-object.c
> index 323f7b2..4ee752f 100644
> --- a/gcc/lto/lto-object.c
> +++ b/gcc/lto/lto-object.c
> @@ -230,8 +230,7 @@ lto_obj_add_section (void *data, const char *name, off_t
> offset,
> void **slot;
> struct lto_section_list *list = loasd->list;
>
> - if (strncmp (name, LTO_SECTION_NAME_PREFIX,
> - strlen (LTO_SECTION_NAME_PREFIX)) != 0)
> + if (strncmp (name, section_name_prefix, strlen (section_name_prefix)))
> return 1;
>
> new_name = xstrdup (name);
> diff --git a/gcc/lto/lto-partition.c b/gcc/lto/lto-partition.c
> index 0451a66..aae2be9 100644
> --- a/gcc/lto/lto-partition.c
> +++ b/gcc/lto/lto-partition.c
> @@ -920,6 +920,8 @@ lto_promote_cross_file_statics (void)
>
> gcc_assert (flag_wpa);
>
> + select_what_to_stream (false);
> +
> /* First compute boundaries. */
> n_sets = ltrans_partitions.length ();
> for (i = 0; i < n_sets; i++)
> diff --git a/gcc/lto/lto.c b/gcc/lto/lto.c
> index 6cbb178..0646da5 100644
> --- a/gcc/lto/lto.c
> +++ b/gcc/lto/lto.c
> @@ -2125,7 +2125,7 @@ lto_section_with_id (const char *name, unsigned
> HOST_WIDE_INT *id)
> {
> const char *s;
>
> - if (strncmp (name, LTO_SECTION_NAME_PREFIX, strlen
> (LTO_SECTION_NAME_PREFIX)))
> + if (strncmp (name, section_name_prefix, strlen (section_name_prefix)))
> return 0;
> s = strrchr (name, '.');
> return s && sscanf (s, "." HOST_WIDE_INT_PRINT_HEX_PURE, id) == 1;
> @@ -2899,6 +2899,10 @@ read_cgraph_and_symbols (unsigned nfiles, const char
> **fnames)
>
> timevar_push (TV_IPA_LTO_DECL_IN);
>
> +#ifdef ACCEL_COMPILER
> + section_name_prefix = OFFLOAD_SECTION_NAME_PREFIX;
> +#endif
> +
> real_file_decl_data
> = decl_data = ggc_cleared_vec_alloc<lto_file_decl_data_ptr> (nfiles + 1);
> real_file_count = nfiles;
> diff --git a/gcc/omp-low.c b/gcc/omp-low.c
> index eb0a7ee..6156e2f 100644
> --- a/gcc/omp-low.c
> +++ b/gcc/omp-low.c
> @@ -257,6 +257,16 @@ is_parallel_ctx (omp_context *ctx)
> }
>
>
> +/* Return true if CTX is for an omp target region. */
> +
> +static inline bool
> +is_targetreg_ctx (omp_context *ctx)
> +{
> + return gimple_code (ctx->stmt) == GIMPLE_OMP_TARGET
> + && gimple_omp_target_kind (ctx->stmt) == GF_OMP_TARGET_KIND_REGION;
> +}
> +
> +
> /* Return true if CTX is for an omp task. */
>
> static inline bool
> @@ -1930,9 +1940,7 @@ create_omp_child_function (omp_context *ctx, bool
> task_copy)
> {
> omp_context *octx;
> for (octx = ctx; octx; octx = octx->outer)
> - if (gimple_code (octx->stmt) == GIMPLE_OMP_TARGET
> - && gimple_omp_target_kind (octx->stmt)
> - == GF_OMP_TARGET_KIND_REGION)
> + if (is_targetreg_ctx (octx))
> {
> target_p = true;
> break;
> @@ -2588,8 +2596,7 @@ check_omp_nesting_restrictions (gimple stmt,
> omp_context *ctx)
> break;
> case GIMPLE_OMP_TARGET:
> for (; ctx != NULL; ctx = ctx->outer)
> - if (gimple_code (ctx->stmt) == GIMPLE_OMP_TARGET
> - && gimple_omp_target_kind (ctx->stmt) == GF_OMP_TARGET_KIND_REGION)
> + if (is_targetreg_ctx (ctx))
> {
> const char *name;
> switch (gimple_omp_target_kind (stmt))
> @@ -8206,6 +8213,7 @@ expand_omp_target (struct omp_region *region)
> if (kind == GF_OMP_TARGET_KIND_REGION)
> {
> unsigned srcidx, dstidx, num;
> + struct cgraph_node *node;
>
> /* If the target region needs data sent from the parent
> function, then the very first statement (except possible
> @@ -8337,6 +8345,11 @@ expand_omp_target (struct omp_region *region)
> push_cfun (child_cfun);
> cgraph_edge::rebuild_edges ();
>
> + /* Prevent IPA from removing child_fn as unreachable, since there are
> no
> + refs from the parent function to child_fn in offload LTO mode. */
> + node = cgraph_node::get (child_fn);
> + node->mark_force_output ();
> +
> /* Some EH regions might become dead, see PR34608. If
> pass_cleanup_cfg isn't the first pass to happen with the
> new child, these dead EH edges might cause problems.
> @@ -9207,6 +9220,19 @@ lower_omp_critical (gimple_stmt_iterator *gsi_p,
> omp_context *ctx)
> DECL_COMMON (decl) = 1;
> DECL_ARTIFICIAL (decl) = 1;
> DECL_IGNORED_P (decl) = 1;
> +
> + /* If '#pragma omp critical' is inside target region, the symbol must
> + have an 'omp declare target' attribute. */
> + omp_context *octx;
> + for (octx = ctx->outer; octx; octx = octx->outer)
> + if (is_targetreg_ctx (octx))
> + {
> + DECL_ATTRIBUTES (decl)
> + = tree_cons (get_identifier ("omp declare target"),
> + NULL_TREE, DECL_ATTRIBUTES (decl));
Here - why not set a flag on cgraph_get_node (decl) instead?
LTO bits are ok apart from the way you split partitioning which I
leave to Honza. Also see my suggestion about that odd "omp declare
target" attribute.
Thanks,
Richard.
> + break;
> + }
> +
> varpool_node::finalize_decl (decl);
>
> splay_tree_insert (critical_name_mutexes, (splay_tree_key) name,
> diff --git a/gcc/passes.c b/gcc/passes.c
> index 5001c3d..0d5667d 100644
> --- a/gcc/passes.c
> +++ b/gcc/passes.c
> @@ -2297,7 +2297,7 @@ ipa_write_summaries_1 (lto_symtab_encoder_t encoder)
> /* Write out summaries for all the nodes in the callgraph. */
>
> void
> -ipa_write_summaries (void)
> +ipa_write_summaries (bool offload_lto_mode)
> {
> lto_symtab_encoder_t encoder;
> int i, order_pos;
> @@ -2308,6 +2308,8 @@ ipa_write_summaries (void)
> if (!flag_generate_lto || seen_error ())
> return;
>
> + select_what_to_stream (offload_lto_mode);
> +
> encoder = lto_symtab_encoder_new (false);
>
> /* Create the callgraph set in the same order used in
> @@ -2334,15 +2336,16 @@ ipa_write_summaries (void)
> renumber_gimple_stmt_uids ();
> pop_cfun ();
> }
> - if (node->definition)
> + if (node->definition && node->need_lto_streaming)
> lto_set_symtab_encoder_in_partition (encoder, node);
> }
>
> FOR_EACH_DEFINED_FUNCTION (node)
> - if (node->alias)
> + if (node->alias && node->need_lto_streaming)
> lto_set_symtab_encoder_in_partition (encoder, node);
> FOR_EACH_DEFINED_VARIABLE (vnode)
> - lto_set_symtab_encoder_in_partition (encoder, vnode);
> + if (vnode->need_lto_streaming)
> + lto_set_symtab_encoder_in_partition (encoder, vnode);
>
> ipa_write_summaries_1 (compute_ltrans_boundary (encoder));
>
> diff --git a/gcc/tree-pass.h b/gcc/tree-pass.h
> index ed109c3..0bc5ca1 100644
> --- a/gcc/tree-pass.h
> +++ b/gcc/tree-pass.h
> @@ -592,7 +592,7 @@ extern void pass_fini_dump_file (opt_pass *);
> extern const char *get_current_pass_name (void);
> extern void print_current_pass (FILE *);
> extern void debug_pass (void);
> -extern void ipa_write_summaries (void);
> +extern void ipa_write_summaries (bool);
> extern void ipa_write_optimization_summaries (struct lto_symtab_encoder_d *);
> extern void ipa_read_summaries (void);
> extern void ipa_read_optimization_summaries (void);
>
--
Richard Biener <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend"orffer
