Prathamesh Kulkarni <prathame...@nvidia.com> writes:
> diff --git a/gcc/lto-streamer-in.cc b/gcc/lto-streamer-in.cc
> index cbf6041fd68..0420183faf8 100644
> --- a/gcc/lto-streamer-in.cc
> +++ b/gcc/lto-streamer-in.cc
> @@ -44,6 +44,7 @@ along with GCC; see the file COPYING3. If not see
> #include "debug.h"
> #include "alloc-pool.h"
> #include "toplev.h"
> +#include "stor-layout.h"
>
> /* Allocator used to hold string slot entries for line map streaming. */
> static struct object_allocator<struct string_slot> *string_slot_allocator;
> @@ -1752,6 +1753,17 @@ 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
> + /* For decl with aggregate type, host streams out VOIDmode.
> + Compute the correct DECL_MODE by calling relayout_decl. */
> + if ((VAR_P (expr)
> + || TREE_CODE (expr) == PARM_DECL
> + || TREE_CODE (expr) == FIELD_DECL)
> + && AGGREGATE_TYPE_P (TREE_TYPE (expr))
> + && DECL_MODE (expr) == VOIDmode)
> + relayout_decl (expr);
> +#endif
Genuine question, but: is relayout_decl safe in this context? It does
a lot more than just reset the mode. It also applies the target ABI's
preferences wrt alignment, padding, and so on, rather than preserving
those of the host's.
Thanks,
Richard
> }
> }
>
> diff --git a/gcc/stor-layout.cc b/gcc/stor-layout.cc
> index 10c0809914c..0ff8bd1171e 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 096ca811762..9d9b8c385f6 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 40029437199..329d218e7d4 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 b7205287ffb..7de4447a1b5 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);
