| Message ID | 20141001161332.GB54978@msticlxl57.ims.intel.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Oct 01, 2014 at 08:13:32PM +0400, Ilya Verbin wrote: > @@ -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. > + */ The */ alone on a line is weird, put the last word on the next line too. > + 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) While I hope the varpool code puts only decls that have DECL_ATTRIBUTES into FOR_EACH_DEFINED_VARIABLE, it would be better to put the less expensive tests first, i.e. the last two first, then lookup_attribute. Also, DECL_SIZE is a tree, so == NULL_TREE? And, once there is an option to select which offload targets to generate code for (or none), initialize_offload () should supposedly return false if the user requested no offloading on the command line. The omp-low.c changes look good, for the cgraph/LTO stuff I defer to Honza and/or Richard, if they are fine with the changes, so am I. Jakub
On Wed, Oct 08, 2014 at 10:45:22AM +0200, Jakub Jelinek wrote: > And, once there is an option to select which offload targets to generate > code for (or none), initialize_offload () should supposedly return false > if the user requested no offloading on the command line. After some thought, I take this back. We should always stream .gnu.offload_lto_* if we have any target regions or omp declare target functions/vars. The decision should be done during linking, if the user wants only host fallback, during linking we should just throw away those .gnu.offload_lto_* sections (could also tweak defaults for that e.g. in libgomp.spec). Thinking with a distro hat now, if gcc is configured as offloading for say MIC, PTX and HSA?, it would be nice if the default choice was dependent on which offloading compilers the user decided to actually install. So one could add a default for %{!foffloading:-foffloading=x86_64-intelmic-linux-gnu} if MIC offloading compiler is installed and PTX/HSA is not (for example, don't remember the name of the option we discussed). Jakub
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); >
On 15 Oct 16:23, Richard Biener wrote: > > +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) So you propose to set global have_offload flag somewhere in expand_omp_target, etc. where functions and global variables are created? > > 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? In this patch series offloading is implemented only for OpenMP. OpenACC guys will add flag_openacc here. > > /* If LTO is enabled, initialize the streamer hooks needed by GIMPLE. */ > > - if (flag_lto) > > + if (flag_lto || flag_openmp) > > flag_generate_lto? > > > /* 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 Currently this is not working, since symbol_table::compile is executed before ipa_passes. But with global have_offload it should work. > > +/* 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? > > + /* 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? I thought that select_what_to_stream is exactly what you've suggested. Could you please clarify this? You propose to replace "omp declare target" attribure with some cgraph node flag like need_offload? But we'll need need_lto_streaming anyway, since for LTO it should be 1 for all nodes, but for offloading it should be equal to need_offload. Thanks, -- Ilya
On Mon, Oct 20, 2014 at 03:19:35PM +0400, Ilya Verbin wrote: > > > + /* 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? > > I thought that select_what_to_stream is exactly what you've suggested. > Could you please clarify this? You propose to replace "omp declare target" > attribure with some cgraph node flag like need_offload? But we'll need > need_lto_streaming anyway, since for LTO it should be 1 for all nodes, but for > offloading it should be equal to need_offload. Note, the attribute is created usually by the FEs, at points where cgraph/varpool nodes can't be created yet. So, it is not possible to get rid of the artificial attribute easily, it could be cached in some cgraph/varpool bit field of course. Jakub
On 20 Oct 15:19, Ilya Verbin wrote: > On 15 Oct 16:23, Richard Biener wrote: > > > +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) > > > > +/* 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? > > > > + /* 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? > > I thought that select_what_to_stream is exactly what you've suggested. > Could you please clarify this? You propose to replace "omp declare target" > attribure with some cgraph node flag like need_offload? But we'll need > need_lto_streaming anyway, since for LTO it should be 1 for all nodes, but for > offloading it should be equal to need_offload. We have to set the global have_offload flag in few places in omp-low.c and in FE (c/c-decl.c:c_decl_attributes, fortran/trans-common.c:build_common_decl, fortran/trans-decl.c:add_attributes_to_decl). This way looks for me a bit more complicated than the current approach. Actually, we could follow Jakub's suggestion of caching the attribute in a bit field, and set the global have_offload flag on the run without any changes in FE. However, I don't know a suitable place for it. If you agree with the approach, could you please specify the place? Thanks, -- Ilya
On Fri, Oct 24, 2014 at 06:16:01PM +0400, Ilya Verbin wrote: > We have to set the global have_offload flag in few places in omp-low.c and in FE > (c/c-decl.c:c_decl_attributes, fortran/trans-common.c:build_common_decl, > fortran/trans-decl.c:add_attributes_to_decl). > This way looks for me a bit more complicated than the current approach. > > Actually, we could follow Jakub's suggestion of caching the attribute in a bit > field, and set the global have_offload flag on the run without any changes in > FE. However, I don't know a suitable place for it. If you agree with the > approach, could you please specify the place? Can't you do that when creating the cgraph or varpool nodes? I'd expect the attribute to be already present on the decls at those spots. Jakub
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; +} + 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 +2081,18 @@ 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) 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; 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)); +} + /* 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); 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)); + 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);