RE: [PATCH v4 7/8] gdb/record: Define new version of the record-save section

["Schimpe, Christina" <christina.schimpe@intel.com>]

> -----Original Message-----
> From: Guinevere Larsen <guinevere@redhat.com>
> Sent: Dienstag, 2. Juni 2026 16:34
> To: gdb-patches@sourceware.org
> Cc: Guinevere Larsen <guinevere@redhat.com>; Thiago Jung Bauermann
> <thiago.bauermann@linaro.org>; Eli Zaretskii <eliz@gnu.org>
> Subject: [PATCH v4 7/8] gdb/record: Define new version of the record-save
> section
> 
> With the changes to the internal representation of the history, we can no
> longer support the previous record save format. This commit makes it official,
> documenting the new format and changing the magic number.
> 
> Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
> Reviewed-By: Eli Zaretskii <eliz@gnu.org>
> ---
>  gdb/NEWS          |  4 ++++
>  gdb/record-full.c | 35 +++++++++++++++++++++++++++++++----
>  2 files changed, 35 insertions(+), 4 deletions(-)
> 
> diff --git a/gdb/NEWS b/gdb/NEWS
> index 7c8cf9af4c2..4dd3d84c19d 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -51,6 +51,10 @@
> 
>  * Support for the binary file format dbx has been removed.
> 
> +* The format for a saved execution record, created when the command
> +  'record save' is used, has been updated, and previous formats are
> +  no longer supported.
> +
>  * When connected to an extended-remote target GDB can now
>    automatically set the 'remote exec-file' in some cases.  GDB will
>    auto set the remote exec-file only if the remote wasn't started with diff --git
> a/gdb/record-full.c b/gdb/record-full.c index 0dd4207e0c6..4e8326e1298
> 100644
> --- a/gdb/record-full.c
> +++ b/gdb/record-full.c
> @@ -79,7 +79,8 @@
>    ((record_full_next_insn != record_full_list.size ()) \
>      || ::execution_direction == EXEC_REVERSE)
> 
> -#define RECORD_FULL_FILE_MAGIC	netorder32(0x20091016)
> +#define RECORD_FULL_FILE_MAGIC_OLD	netorder32(0x20091016)
> +#define RECORD_FULL_FILE_MAGIC	netorder32(0x20260415)
> 
>  /* These are the core structs of the process record functionality.
> 
> @@ -2214,6 +2215,27 @@ record_full_core_target::has_execution (inferior
> *inf)
>         8 bytes: memory address (network byte order).
>         n bytes: memory value (n == memory length).
> 
> +   Version 3 (all numbers are in network order).
> +     4 bytes: Magic number (0x20260415).
> +       NOTE: be sure to change whenever this file format changes!
> +
> +    Records:
> +      record_full_instruction:
> +	1 byte: signal.
> +	4 bytes: number of reg and mem entries for this instruction.
> +	4 bytes: instruction sequence number.
> +	4 bytes: PC register ID.
> +	N bytes: PC address of instruction (N == size of PC).
> +	Effects:
> +	  record_full_reg:
> +	    1 byte: record_type (record_full_reg, see enum record_full_type).
> +	    4 bytes: Register ID.
> +	    n bytes: register value (n == actual register size).
> +	  record_full_mem:
> +	    1 byte: record_type (record_full_mem, see enum record_full_type).
> +	    4 bytes: memory length.
> +	    8 bytes: memory address.
> +	    n bytes: memory value (n = memory length).
>  */
> 
>  /* bfdcore_read -- read bytes from a core file section.  */ @@ -2409,9
> +2431,14 @@ record_full_restore (struct bfd &cbfd)
>    /* Check the magic code.  */
>    bfdcore_read (&cbfd, osec, &magic, sizeof (magic), &bfd_offset);
>    if (magic != RECORD_FULL_FILE_MAGIC)
> -    error (_("Version mismatch or file format error in core file %ps."),
> -	   styled_string (file_name_style.style (),
> -			  bfd_get_filename (&cbfd)));
> +    {
> +      if (magic == RECORD_FULL_FILE_MAGIC_OLD)
> +	error (_("This old recording format is no longer supported."));
> +      else
> +	error (_("Version mismatch or file format error in core file %ps."),
> +	       styled_string (file_name_style.style (),
> +			      bfd_get_filename (&cbfd)));
> +    }
>    if (record_debug)
>      gdb_printf (gdb_stdlog,
>  		"  Reading 4-byte magic cookie "
> --
> 2.54.0
> 

LGTM.

Reviewed-By: Christina Schimpe <christina.schimpe@intel.com>

Christina
Intel Deutschland GmbH

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