[PATCH 2/7] OpenMP 4.0 offloading infrastructure: LTO streaming.

gcc/
	* cgraph.c: Include context.h.
	(cgraph_node::create): Set node->offloadable and g->have_offload if
	decl have "omp declare target" attribute.
	* cgraph.h (symtab_node): Add need_lto_streaming and offloadable flags.
	* cgraphunit.c: Include lto-section-names.h.
	(ipa_passes): Call ipa_write_summaries if there is something to write to
	OFFLOAD_SECTION_NAME_PREFIX sections.
	(symbol_table::compile): Set flag_generate_lto if there is something to
	offload.
	Replace flag_lto with flag_generate_lto before lto_streamer_hooks_init.
	* context.c (gcc::context::context): Initialize have_offload with false.
	* context.h (class context): Add have_offload flag.
	* ipa-inline-analysis.c (inline_generate_summary): Do not exit under
	flag_generate_lto.
	(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: Include context.h.
	(is_targetreg_ctx): New function.
	(scan_sharing_clauses): Use offloadable flag, instead of an attribute.
	(create_omp_child_function, check_omp_nesting_restrictions): Use new
	is_targetreg_ctx function.  Replace usage of "omp declare target"
	attribute with a cgraph_node flag offloadable.
	(expand_omp_target): Set mark_force_output for offloadable functions.
	(lower_omp_critical): Set offloadable flag 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.
	* varpool.c: Include context.h.
	(varpool_node::get_create): Set node->offloadable and g->have_offload if
	decl have "omp declare target" attribute.

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.

Co-Authored-By: Andrey Turetskiy <andrey.turetskiy@intel.com>
Co-Authored-By: Bernd Schmidt <bernds@codesourcery.com>
Co-Authored-By: Michael Zolotukhin <michael.v.zolotukhin@intel.com>

From-SVN: r217486

1 files changed, 36 insertions, 18 deletions

diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index e7d8a7e..8ac5d94 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -86,6 +86,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-nested.h"
 #include "tree-eh.h"
 #include "cilk.h"
+#include "context.h"
 
 
 /* Lowering of OpenMP parallel and workshare constructs proceeds in two
@@ -273,6 +274,16 @@ 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
@@ -1642,8 +1653,7 @@ scan_sharing_clauses (tree clauses, omp_context *ctx)
 	  if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
 	      && DECL_P (decl)
 	      && is_global_var (maybe_lookup_decl_in_outer_ctx (decl, ctx))
-	      && lookup_attribute ("omp declare target",
-				   DECL_ATTRIBUTES (decl)))
+	      && varpool_node::get_create (decl)->offloadable)
 	    break;
 	  if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
 	      && OMP_CLAUSE_MAP_KIND (c) == OMP_CLAUSE_MAP_POINTER)
@@ -1783,8 +1793,7 @@ scan_sharing_clauses (tree clauses, omp_context *ctx)
 	  decl = OMP_CLAUSE_DECL (c);
 	  if (DECL_P (decl)
 	      && is_global_var (maybe_lookup_decl_in_outer_ctx (decl, ctx))
-	      && lookup_attribute ("omp declare target",
-				   DECL_ATTRIBUTES (decl)))
+	      && varpool_node::get_create (decl)->offloadable)
 	    break;
 	  if (DECL_P (decl))
 	    {
@@ -1938,26 +1947,19 @@ create_omp_child_function (omp_context *ctx, bool task_copy)
   DECL_EXTERNAL (decl) = 0;
   DECL_CONTEXT (decl) = NULL_TREE;
   DECL_INITIAL (decl) = make_node (BLOCK);
-  bool target_p = false;
-  if (lookup_attribute ("omp declare target",
-			DECL_ATTRIBUTES (current_function_decl)))
-    target_p = true;
+  if (cgraph_node::get (current_function_decl)->offloadable)
+    cgraph_node::get_create (decl)->offloadable = 1;
   else
     {
       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;
+	    cgraph_node::get_create (decl)->offloadable = 1;
+	    g->have_offload = true;
 	    break;
 	  }
     }
-  if (target_p)
-    DECL_ATTRIBUTES (decl)
-      = tree_cons (get_identifier ("omp declare target"),
-		   NULL_TREE, DECL_ATTRIBUTES (decl));
 
   t = build_decl (DECL_SOURCE_LOCATION (decl),
 		  RESULT_DECL, NULL_TREE, void_type_node);
@@ -2663,8 +2665,7 @@ 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))
@@ -8281,6 +8282,7 @@ 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
@@ -8412,6 +8414,11 @@ 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.
@@ -9326,6 +9333,17 @@ 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
+	     be marked for offloading.  */
+	  omp_context *octx;
+	  for (octx = ctx->outer; octx; octx = octx->outer)
+	    if (is_targetreg_ctx (octx))
+	      {
+		varpool_node::get_create (decl)->offloadable = 1;
+		break;
+	      }
+
 	  varpool_node::finalize_decl (decl);
 
 	  splay_tree_insert (critical_name_mutexes, (splay_tree_key) name,