On Mon, 19 Jun 2023, [email protected] wrote:
> From: Pan Li <[email protected]>
>
> We extend the machine mode from 8 to 16 bits already. But there still
> one placing missing from the tree-streamer. It has one hard coded array
> for the machine code like size 256.
>
> In the lto pass, we memset the array by MAX_MACHINE_MODE count but the
> value of the MAX_MACHINE_MODE will grow as more and more modes are added.
> While the machine mode array in tree-streamer still leave 256 as is.
>
> Then, when the MAX_MACHINE_MODE is greater than 256, the memset of
> lto_output_init_mode_table will touch the memory out of range unexpected.
>
> This patch would like to take the MAX_MACHINE_MODE as the size of the
> array in tree-streamer, to make sure there is no potential unexpected
> memory access in future.
Please review more careful:
void
lto_input_mode_table (struct lto_file_decl_data *file_data)
{
...
while ((m = bp_unpack_value (&bp, 8)) != VOIDmode)
reads 8 bits again.
ibit = bp_unpack_value (&bp, 8);
fbit = bp_unpack_value (&bp, 8);
likewise.
Also file_data->mode_table is indexed by the _host_ mode, so you
have to allocate enough space to fill in all streamed modes but
you are using the targets MAX_MACHINE_MODE here. I think we
need to stream the hosts MAX_MACHINE_MODE.
Richard.
> Signed-off-by: Pan Li <[email protected]>
>
> gcc/ChangeLog:
>
> * lto-streamer-in.cc (lto_input_mode_table): Use
> MAX_MACHINE_MODE for memory allocation.
> * tree-streamer.cc: Use MAX_MACHINE_MODE for array size.
> * tree-streamer.h (streamer_mode_table): Ditto.
> (bp_pack_machine_mode): Ditto.
> (bp_unpack_machine_mode): Ditto.
> ---
> gcc/lto-streamer-in.cc | 3 ++-
> gcc/tree-streamer.cc | 2 +-
> gcc/tree-streamer.h | 7 ++++---
> 3 files changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/gcc/lto-streamer-in.cc b/gcc/lto-streamer-in.cc
> index 2cb83406db5..102b7e18526 100644
> --- a/gcc/lto-streamer-in.cc
> +++ b/gcc/lto-streamer-in.cc
> @@ -1985,7 +1985,8 @@ lto_input_mode_table (struct lto_file_decl_data
> *file_data)
> internal_error ("cannot read LTO mode table from %s",
> file_data->file_name);
>
> - unsigned char *table = ggc_cleared_vec_alloc<unsigned char> (1 << 8);
> + unsigned char *table = ggc_cleared_vec_alloc<unsigned char> (
> + MAX_MACHINE_MODE);
> file_data->mode_table = table;
> const struct lto_simple_header_with_strings *header
> = (const struct lto_simple_header_with_strings *) data;
> diff --git a/gcc/tree-streamer.cc b/gcc/tree-streamer.cc
> index ed65a7692e3..a28ef9c7920 100644
> --- a/gcc/tree-streamer.cc
> +++ b/gcc/tree-streamer.cc
> @@ -35,7 +35,7 @@ along with GCC; see the file COPYING3. If not see
> During streaming in, we translate the on the disk mode using this
> table. For normal LTO it is set to identity, for ACCEL_COMPILER
> depending on the mode_table content. */
> -unsigned char streamer_mode_table[1 << 8];
> +unsigned char streamer_mode_table[MAX_MACHINE_MODE];
>
> /* Check that all the TS_* structures handled by the streamer_write_* and
> streamer_read_* routines are exactly ALL the structures defined in
> diff --git a/gcc/tree-streamer.h b/gcc/tree-streamer.h
> index 170d61cf20b..be3a1938e76 100644
> --- a/gcc/tree-streamer.h
> +++ b/gcc/tree-streamer.h
> @@ -75,7 +75,7 @@ void streamer_write_tree_body (struct output_block *, tree);
> void streamer_write_integer_cst (struct output_block *, tree);
>
> /* In tree-streamer.cc. */
> -extern unsigned char streamer_mode_table[1 << 8];
> +extern unsigned char streamer_mode_table[MAX_MACHINE_MODE];
> void streamer_check_handled_ts_structures (void);
> bool streamer_tree_cache_insert (struct streamer_tree_cache_d *, tree,
> hashval_t, unsigned *);
> @@ -108,7 +108,7 @@ inline void
> bp_pack_machine_mode (struct bitpack_d *bp, machine_mode mode)
> {
> streamer_mode_table[mode] = 1;
> - bp_pack_enum (bp, machine_mode, 1 << 8, mode);
> + bp_pack_enum (bp, machine_mode, MAX_MACHINE_MODE, mode);
> }
>
> inline machine_mode
> @@ -116,7 +116,8 @@ bp_unpack_machine_mode (struct bitpack_d *bp)
> {
> return (machine_mode)
> ((class lto_input_block *)
> - bp->stream)->mode_table[bp_unpack_enum (bp, machine_mode, 1 << 8)];
> + bp->stream)->mode_table[bp_unpack_enum (bp, machine_mode,
> + MAX_MACHINE_MODE)];
> }
>
> #endif /* GCC_TREE_STREAMER_H */
>
--
Richard Biener <[email protected]>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)
