[offloading] Error on missing symbols

When compiling an OpenMP or OpenACC program containing a reference in the
offloaded code to a symbol that has not been included in the offloaded code,
the offloading compiler may ICE in lto1.

Fix this by erroring out instead, mentioning the problematic symbol:
...
error: variable 'var' has been referenced in offloaded code but hasn't
  been marked to be included in the offloaded code
lto1: fatal error: errors during merging of translation units
compilation terminated.
...

Build x86_64 with nvptx accelerator and reg-tested libgomp.

Build x86_64 and reg-tested libgomp.

2018-12-14  Tom de Vries  <tdevries@suse.de>

	* lto-cgraph.c (verify_node_partition): New function.
	(input_overwrite_node, input_varpool_node): Use verify_node_partition.

	* testsuite/libgomp.c-c++-common/function-not-offloaded-aux.c: New test.
	* testsuite/libgomp.c-c++-common/function-not-offloaded.c: New test.
	* testsuite/libgomp.c-c++-common/variable-not-offloaded.c: New test.
	* testsuite/libgomp.oacc-c-c++-common/function-not-offloaded.c: New test.
	* testsuite/libgomp.oacc-c-c++-common/variable-not-offloaded.c: New test.

From-SVN: r267134

1 files changed, 32 insertions, 7 deletions

diff --git a/gcc/lto-cgraph.c b/gcc/lto-cgraph.c
index 99998cc3..536e73c 100644
--- a/gcc/lto-cgraph.c
+++ b/gcc/lto-cgraph.c
@@ -1091,6 +1091,36 @@ output_offload_tables (void)
     }
 }
 
+/* Verify the partitioning of NODE.  */
+
+static inline void
+verify_node_partition (symtab_node *node)
+{
+  if (flag_ltrans)
+    return;
+
+#ifdef ACCEL_COMPILER
+  if (node->in_other_partition)
+    {
+      if (TREE_CODE (node->decl) == FUNCTION_DECL)
+	error_at (DECL_SOURCE_LOCATION (node->decl),
+		  "function %qs has been referenced in offloaded code but"
+		  " hasn%'t been marked to be included in the offloaded code",
+		  node->name ());
+      else if (VAR_P (node->decl))
+	error_at (DECL_SOURCE_LOCATION (node->decl),
+		  "variable %qs has been referenced in offloaded code but"
+		  " hasn%'t been marked to be included in the offloaded code",
+		  node->name ());
+      else
+	gcc_unreachable ();
+    }
+#else
+  gcc_assert (!node->in_other_partition
+	      && !node->used_from_other_partition);
+#endif
+}
+
 /* Overwrite the information in NODE based on FILE_DATA, TAG, FLAGS,
    STACK_SIZE, SELF_TIME and SELF_SIZE.  This is called either to initialize
    NODE or to replace the values in it, for instance because the first
@@ -1153,9 +1183,7 @@ input_overwrite_node (struct lto_file_decl_data *file_data,
   node->resolution = bp_unpack_enum (bp, ld_plugin_symbol_resolution,
 				     LDPR_NUM_KNOWN);
   node->split_part = bp_unpack_value (bp, 1);
-  gcc_assert (flag_ltrans
-	      || (!node->in_other_partition
-		  && !node->used_from_other_partition));
+  verify_node_partition (node);
 }
 
 /* Return string alias is alias of.  */
@@ -1366,10 +1394,7 @@ input_varpool_node (struct lto_file_decl_data *file_data,
     node->set_section_for_node (section);
   node->resolution = streamer_read_enum (ib, ld_plugin_symbol_resolution,
 					        LDPR_NUM_KNOWN);
-  gcc_assert (flag_ltrans
-	      || (!node->in_other_partition
-		  && !node->used_from_other_partition));
-
+  verify_node_partition (node);
   return node;
 }