Recompute TYPE_MODE and DECL_MODE for aggregate type for acclerator.

The patch streams out VOIDmode for aggregate types with offloading enabled,
and recomputes appropriate TYPE_MODE and DECL_MODE while streaming-in on accel
side. The rationale for this change is to avoid streaming out host-specific
modes that may be used for aggregate types, which may not be representable on
the accelerator. For eg, AArch64 uses OImode for ARRAY_TYPE whose size is 256-bits,
and nvptx doesn't have OImode, and thus ends up emitting an error from
lto_input_mode_table.

gcc/ChangeLog:
	* lto-streamer-in.cc: (lto_read_tree_1): Set DECL_MODE (expr) to
	TREE_TYPE (TYPE_MODE (expr)) if TREE_TYPE (expr) is aggregate type and
	offloading is enabled.
	* stor-layout.cc (layout_type): Move computation of mode for
	ARRAY_TYPE from ...
	(compute_array_mode): ... to here.
	* stor-layout.h (compute_array_mode): Declare.
	* tree-streamer-in.cc: Include stor-layout.h.
	(unpack_ts_common_value_fields): Call compute_array_mode if offloading
	is enabled.
	* tree-streamer-out.cc (pack_ts_fixed_cst_value_fields): Stream out
	VOIDmode if decl has aggregate type and offloading is enabled.
	(pack_ts_type_common_value_fields): Stream out VOIDmode for aggregate
	type if offloading is enabled.

Signed-off-by: Prathamesh Kulkarni <prathameshk@nvidia.com>

5 files changed, 69 insertions, 20 deletions

diff --git a/gcc/lto-streamer-in.cc b/gcc/lto-streamer-in.cc
index cbf6041..64f7580 100644
--- a/gcc/lto-streamer-in.cc
+++ b/gcc/lto-streamer-in.cc
@@ -1752,6 +1752,15 @@ lto_read_tree_1 (class lto_input_block *ib, class data_in *data_in, tree expr)
 	 with -g1, see for example PR113488.  */
       else if (DECL_P (expr) && DECL_ABSTRACT_ORIGIN (expr) == expr)
 	DECL_ABSTRACT_ORIGIN (expr) = NULL_TREE;
+
+#ifdef ACCEL_COMPILER
+      if ((VAR_P (expr)
+	   || TREE_CODE (expr) == PARM_DECL
+	   || TREE_CODE (expr) == FIELD_DECL)
+	  && AGGREGATE_TYPE_P (TREE_TYPE (expr))
+	  && DECL_MODE (expr) == VOIDmode)
+	SET_DECL_MODE (expr, TYPE_MODE (TREE_TYPE (expr)));
+#endif
     }
 }
 
diff --git a/gcc/stor-layout.cc b/gcc/stor-layout.cc
index 10c0809..0ff8bd1 100644
--- a/gcc/stor-layout.cc
+++ b/gcc/stor-layout.cc
@@ -2396,6 +2396,32 @@ finish_builtin_struct (tree type, const char *name, tree fields,
   layout_decl (TYPE_NAME (type), 0);
 }
 
+/* Compute TYPE_MODE for TYPE (which is ARRAY_TYPE).  */
+
+void compute_array_mode (tree type)
+{
+  gcc_assert (TREE_CODE (type) == ARRAY_TYPE);
+
+  SET_TYPE_MODE (type, BLKmode);
+  if (TYPE_SIZE (type) != 0
+      && ! targetm.member_type_forces_blk (type, VOIDmode)
+      /* BLKmode elements force BLKmode aggregate;
+	 else extract/store fields may lose.  */
+      && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
+	  || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
+    {
+      SET_TYPE_MODE (type, mode_for_array (TREE_TYPE (type),
+					   TYPE_SIZE (type)));
+      if (TYPE_MODE (type) != BLKmode
+	  && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
+	  && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type)))
+	{
+	  TYPE_NO_FORCE_BLK (type) = 1;
+	  SET_TYPE_MODE (type, BLKmode);
+	}
+    }
+}
+
 /* Calculate the mode, size, and alignment for TYPE.
    For an array type, calculate the element separation as well.
    Record TYPE on the chain of permanent or temporary types
@@ -2709,24 +2735,7 @@ layout_type (tree type)
 	align = MAX (align, BITS_PER_UNIT);
 #endif
 	SET_TYPE_ALIGN (type, align);
-	SET_TYPE_MODE (type, BLKmode);
-	if (TYPE_SIZE (type) != 0
-	    && ! targetm.member_type_forces_blk (type, VOIDmode)
-	    /* BLKmode elements force BLKmode aggregate;
-	       else extract/store fields may lose.  */
-	    && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
-		|| TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
-	  {
-	    SET_TYPE_MODE (type, mode_for_array (TREE_TYPE (type),
-						 TYPE_SIZE (type)));
-	    if (TYPE_MODE (type) != BLKmode
-		&& STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
-		&& TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type)))
-	      {
-		TYPE_NO_FORCE_BLK (type) = 1;
-		SET_TYPE_MODE (type, BLKmode);
-	      }
-	  }
+	compute_array_mode (type);
 	if (AGGREGATE_TYPE_P (element))
 	  TYPE_TYPELESS_STORAGE (type) = TYPE_TYPELESS_STORAGE (element);
 	/* When the element size is constant, check that it is at least as
diff --git a/gcc/stor-layout.h b/gcc/stor-layout.h
index 096ca81..9d9b8c3 100644
--- a/gcc/stor-layout.h
+++ b/gcc/stor-layout.h
@@ -34,6 +34,7 @@ extern tree rli_size_so_far (record_layout_info);
 extern void normalize_rli (record_layout_info);
 extern void place_field (record_layout_info, tree);
 extern void compute_record_mode (tree);
+extern void compute_array_mode (tree);
 extern void finish_bitfield_layout (tree);
 extern void finish_record_layout (record_layout_info, int);
 extern void finalize_size_functions (void);
diff --git a/gcc/tree-streamer-in.cc b/gcc/tree-streamer-in.cc
index 4002943..329d218 100644
--- a/gcc/tree-streamer-in.cc
+++ b/gcc/tree-streamer-in.cc
@@ -35,6 +35,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "attribs.h"
 #include "asan.h"
 #include "opts.h"
+#include "stor-layout.h"
 
 
 /* Read a STRING_CST from the string table in DATA_IN using input
@@ -395,6 +396,17 @@ unpack_ts_type_common_value_fields (struct bitpack_d *bp, tree expr)
 #ifdef ACCEL_COMPILER
   if (TYPE_ALIGN (expr) > targetm.absolute_biggest_alignment)
     SET_TYPE_ALIGN (expr, targetm.absolute_biggest_alignment);
+
+  /* Host streams out VOIDmode for aggregate type. */
+  if (AGGREGATE_TYPE_P (expr) && TYPE_MODE (expr) == VOIDmode)
+    {
+      if (TREE_CODE (expr) == ARRAY_TYPE)
+	compute_array_mode (expr);
+      else if (RECORD_OR_UNION_TYPE_P (expr))
+	compute_record_mode (expr);
+      else
+	gcc_unreachable ();
+    }
 #endif
 }
 
diff --git a/gcc/tree-streamer-out.cc b/gcc/tree-streamer-out.cc
index b720528..7de4447 100644
--- a/gcc/tree-streamer-out.cc
+++ b/gcc/tree-streamer-out.cc
@@ -187,7 +187,17 @@ pack_ts_fixed_cst_value_fields (struct bitpack_d *bp, tree expr)
 static void
 pack_ts_decl_common_value_fields (struct bitpack_d *bp, tree expr)
 {
-  bp_pack_machine_mode (bp, DECL_MODE (expr));
+  /* Similar to TYPE_MODE, avoid streaming out host-specific DECL_MODE
+     for aggregate type with offloading enabled, and while streaming-in
+     recompute appropriate DECL_MODE for accelerator.  */
+  if (lto_stream_offload_p
+      && (VAR_P (expr)
+	  || TREE_CODE (expr) == PARM_DECL
+	  || TREE_CODE (expr) == FIELD_DECL)
+      && AGGREGATE_TYPE_P (TREE_TYPE (expr)))
+    bp_pack_machine_mode (bp, VOIDmode);
+  else
+    bp_pack_machine_mode (bp, DECL_MODE (expr));
   bp_pack_value (bp, DECL_NONLOCAL (expr), 1);
   bp_pack_value (bp, DECL_VIRTUAL_P (expr), 1);
   bp_pack_value (bp, DECL_IGNORED_P (expr), 1);
@@ -317,10 +327,18 @@ pack_ts_function_decl_value_fields (struct bitpack_d *bp, tree expr)
 static void
 pack_ts_type_common_value_fields (struct bitpack_d *bp, tree expr)
 {
+  /* For offloading, avoid streaming out TYPE_MODE for aggregate type since
+     it may be host-specific. For eg, aarch64 uses OImode for ARRAY_TYPE
+     whose size is 256-bits, which is not representable on accelerator.
+     Instead stream out VOIDmode, and while streaming-in, recompute
+     appropriate TYPE_MODE for accelerator.  */
+  if (lto_stream_offload_p && AGGREGATE_TYPE_P (expr))
+    bp_pack_machine_mode (bp, VOIDmode);
   /* for VECTOR_TYPE, TYPE_MODE reevaluates the mode using target_flags
      not necessary valid in a global context.
      Use the raw value previously set by layout_type.  */
-  bp_pack_machine_mode (bp, TYPE_MODE_RAW (expr));
+  else
+    bp_pack_machine_mode (bp, TYPE_MODE_RAW (expr));
   /* TYPE_NO_FORCE_BLK is private to stor-layout and need
      no streaming.  */
   bp_pack_value (bp, TYPE_PACKED (expr), 1);