RE: [PATCH v4 4/8] gdb/record: c++ify internal structures of record-full.c

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

> -----Original Message-----
> From: Guinevere Larsen <guinevere@redhat.com>
> Sent: Mittwoch, 10. Juni 2026 21:07
> To: Schimpe, Christina <christina.schimpe@intel.com>; gdb-
> patches@sourceware.org
> Cc: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
> Subject: Re: [PATCH v4 4/8] gdb/record: c++ify internal structures of record-
> full.c
> 
> On 6/10/26 11:46 AM, Schimpe, Christina wrote:
> >> -----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>
> >> Subject: [PATCH v4 4/8] gdb/record: c++ify internal structures of
> >> record-full.c
> >>
> >> This commit adds a constructor, destructor, and some methods to the
> >> structures record_full_entry, record_full_reg_entry and
> >> record_full_mem_entry. This is a move to disentangle the internal
> >> representation of the data and how record-full manipulates it for
> replaying.
> >>
> >> Along with this change, record_full_entry is changed to use an
> >> std::variant, since it was basically doing that already, but now we
> >> have the stdlibc++ error checking to make sure we're only accessing
> elements we're allowed to.
> >>
> >> Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
> >> ---
> >>   gdb/record-full.c | 613 ++++++++++++++++++++++++----------------------
> >>   1 file changed, 326 insertions(+), 287 deletions(-)
> >>
> >> diff --git a/gdb/record-full.c b/gdb/record-full.c index
> >> a3a31e7276f..73de84372b0 100644
> >> --- a/gdb/record-full.c
> >> +++ b/gdb/record-full.c
> >> @@ -51,6 +51,7 @@
> >>   #include <optional>
> >>   #include <deque>
> >>   #include <signal.h>
> >> +#include <variant>
> >>
> >>   /* This module implements "target record-full", also known as "process
> >>      record and replay".  This target sits on top of a "normal"
> >> target @@ -92,13
> >> +93,116 @@ struct record_full_mem_entry
> >>     CORE_ADDR addr;
> >>     int len;
> >>     /* Set this flag if target memory for this entry
> >> -     can no longer be accessed.  */
> >> -  int mem_entry_not_accessible;
> >> +     can be accessed.  */
> >> +  bool mem_entry_accessible;
> >>     union
> >>     {
> >>       gdb_byte *ptr;
> >>       gdb_byte buf[sizeof (gdb_byte *)];
> >>     } u;
> >> +
> >> +  record_full_mem_entry () : addr (0), len (0), mem_entry_accessible
> >> + (true)  { }
> >> +
> >> +  record_full_mem_entry (CORE_ADDR mem_addr, int mem_len)  {
> >> +    addr = mem_addr;
> >> +    len = mem_len;
> >> +    if (len > sizeof (u.buf))
> >> +      u.ptr = new gdb_byte[len];
> >> +    mem_entry_accessible = true;
> >> +  }
> >> +
> >> +  record_full_mem_entry (record_full_mem_entry &&other)  {
> >> +    addr = other.addr;
> >> +    len = other.len;
> >> +    memcpy (u.buf, other.u.buf, sizeof (u.buf));
> >> +    mem_entry_accessible = other.mem_entry_accessible;
> >> +    /* With len == 0, OTHER is guaranteed to not try to free the
> >> +       memory when it is destructed.  */
> >> +    other.len = 0;
> >> +  }
> >> +
> >> +  ~record_full_mem_entry ()
> >> +  {
> >> +    if (len > sizeof (u.buf))
> >> +      delete[] u.ptr;
> >> +  }
> >> +
> >> +  record_full_mem_entry &operator= (record_full_mem_entry &&other)
> {
> >> +    gdb_assert (this != &other);
> >> +    addr = other.addr;
> >> +    len = other.len;
> >> +    memcpy (u.buf, other.u.buf, sizeof (u.buf));
> >> +    mem_entry_accessible = other.mem_entry_accessible;
> >> +    /* With len == 0, OTHER is guaranteed to not try to free the
> >> +       memory when it is destructed.  */
> >> +    other.len = 0;
> >> +    return *this;
> >> +  }
> >> +
> >> +  DISABLE_COPY_AND_ASSIGN (record_full_mem_entry);
> >> +
> >> +  gdb_byte *get_loc ()
> >> +  {
> >> +    if (len > sizeof (u.buf))
> >> +      return u.ptr;
> >> +    else
> >> +      return u.buf;
> >> +  }
> >> +
> >> +  bool execute (gdbarch *gdbarch)
> >> +  {
> >> +    /* Nothing to do if the memory is flagged not_accessible.  */
> >> +    if (!mem_entry_accessible)
> >> +      return false;
> >> +
> >> +    gdb::byte_vector buf (len);
> >> +
> >> +    if (record_debug > 1)
> >> +      gdb_printf (gdb_stdlog,
> >> +		  "Process record: record_full_mem %s to "
> >> +		  "inferior addr = %s len = %d.\n",
> >> +		  host_address_to_string (this),
> >> +		  paddress (gdbarch, addr),
> >> +		  len);
> >> +
> >> +    if (record_read_memory (gdbarch, addr, buf.data (), len))
> >> +      mem_entry_accessible = false;
> >> +    else
> >> +      {
> >> +	if (target_write_memory (addr,
> >> +				 get_loc (),
> >> +				 len))
> >> +	  {
> >> +	    mem_entry_accessible = false;
> >> +	    if (record_debug)
> >> +	      warning (_("Process record: error writing memory at "
> >> +			 "addr = %s len = %d."),
> >> +		       paddress (gdbarch, addr),
> >> +		       len);
> >> +	  }
> >> +	else
> >> +	  {
> >> +	    memcpy (get_loc (), buf.data (), len);
> >> +
> >> +	    /* We've changed memory --- check if a hardware
> >> +	       watchpoint should trap.  Note that this
> >> +	       presently assumes the target beneath supports
> >> +	       continuable watchpoints.  On non-continuable
> >> +	       watchpoints target, we'll want to check this
> >> +	       _before_ actually doing the memory change, and
> >> +	       not doing the change at all if the watchpoint
> >> +	       traps.  */
> >> +	    if (hardware_watchpoint_inserted_in_range
> >> +		(current_inferior ()->aspace.get (), addr, len))
> >> +	      return true;
> >> +	  }
> >> +      }
> >> +    return false;
> >> +  }
> >>   };
> >>
> >>   struct record_full_reg_entry
> >> @@ -110,6 +214,71 @@ struct record_full_reg_entry
> >>       gdb_byte *ptr;
> >>       gdb_byte buf[2 * sizeof (gdb_byte *)];
> >>     } u;
> >> +
> >> +  record_full_reg_entry () : num (0), len (0) { }
> >> +
> >> +  record_full_reg_entry (gdbarch *gdbarch, int regnum)  {
> >> +    num = regnum;
> >> +    len = register_size (gdbarch, regnum);
> >> +    if (len > sizeof (u.buf))
> >> +      u.ptr = new gdb_byte[len];
> >> +  }
> >> +
> >> +  record_full_reg_entry (record_full_reg_entry &&other)  {
> >> +    num = other.num;
> >> +    len = other.len;
> >> +    memcpy (u.buf, other.u.buf, sizeof (u.buf));
> >> +    /* With len == 0, OTHER is guaranteed to not try to free the
> >> +       memory when it is destructed.  */
> >> +    other.len = 0;
> >> +  }
> >> +
> >> +  ~record_full_reg_entry ()
> >> +  {
> >> +    if (len > sizeof (u.buf))
> >> +      delete[] u.ptr;
> >> +  }
> >> +
> >> +  record_full_reg_entry &operator=(record_full_reg_entry &&other)  {
> >> +    gdb_assert (this != &other);
> >> +    num = other.num;
> >> +    len = other.len;
> >> +    memcpy (u.buf, other.u.buf, sizeof (u.buf));
> >> +    /* With len == 0, OTHER is guaranteed to not try to free the
> >> +       memory when it is destructed.  */
> >> +    other.len = 0;
> >> +    return *this;
> >> +  }
> >> +
> >> +  DISABLE_COPY_AND_ASSIGN (record_full_reg_entry);
> >> +
> >> +  gdb_byte *get_loc ()
> >> +  {
> >> +    if (len > sizeof (u.buf))
> >> +      return u.ptr;
> >> +    else
> >> +      return u.buf;
> >> +  }
> >> +
> >> +  bool execute (regcache *regcache)
> >> +  {
> >> +    gdb::byte_vector buf (len);
> >> +
> >> +    if (record_debug > 1)
> >> +      gdb_printf (gdb_stdlog,
> >> +		  "Process record: record_full_reg %s to "
> >> +		  "inferior num = %d.\n",
> >> +		  host_address_to_string (this),
> >> +		  num);
> >> +
> >> +    regcache->cooked_read (num, buf);
> >> +    regcache->cooked_write (num, get_loc ());
> >> +    memcpy (get_loc (), buf.data (), len);
> >> +    return false;
> >> +  }
> >>   };
> >>
> >>   enum record_full_type
> >> @@ -118,16 +287,88 @@ enum record_full_type
> >>     record_full_mem
> >>   };
> >>
> >> -struct record_full_entry
> >> +class record_full_entry
> >>   {
> >> -  enum record_full_type type;
> >> -  union
> >> +  std::variant<record_full_reg_entry, record_full_mem_entry> entry;
> >> +
> >> +public:
> >> +  record_full_entry () : entry (record_full_reg_entry ()) {}
> >> +
> >> +  /* Constructor for a register entry.  Type is here to make it
> >> +     easier to recognize it in the constructor calls, it isn't
> >> +     actually important.  */
> >> +  record_full_entry (record_full_type reg_type, gdbarch *gdbarch,
> >> +		     int regnum)
> >> +  : entry(record_full_reg_entry (gdbarch, regnum))
> >>     {
> >> -    /* reg */
> >> -    struct record_full_reg_entry reg;
> >> -    /* mem */
> >> -    struct record_full_mem_entry mem;
> >> -  } u;
> >> +    gdb_assert (reg_type == record_full_reg);  }
> >> +
> >> +  record_full_entry (record_full_type mem_type, CORE_ADDR addr, int
> >> + len)
> >> +  : entry(record_full_mem_entry (addr, len))  {
> >> +    gdb_assert (mem_type == record_full_mem);  }
> >> +
> >> +  record_full_entry (record_full_entry &&other)
> >> +  : entry (std::move (other.entry))
> >> +  {
> >> +  }
> >> +
> >> +  DISABLE_COPY_AND_ASSIGN (record_full_entry);
> >> +
> >> +  record_full_reg_entry& reg ()
> >> +  {
> >> +    gdb_assert (type () == record_full_reg);
> >> +    return std::get<record_full_reg_entry> (entry);  }
> >> +
> >> +  record_full_mem_entry& mem ()
> >> +  {
> >> +    gdb_assert (type () == record_full_mem);
> >> +    return std::get<record_full_mem_entry> (entry);  }
> >> +
> >> +  record_full_type type () const
> >> +  {
> >> +    switch (entry.index ())
> >> +    {
> >> +    case 0:
> >> +      return record_full_reg;
> >> +    case 1:
> >> +      return record_full_mem;
> >> +    }
> >> +    gdb_assert_not_reached ("Impossible variant index");  }
> >> +
> >> +  /* Get the pointer to the data stored by this entry.  */  gdb_byte
> >> + *get_loc ()  {
> >> +    switch (type ())
> >> +    {
> >> +    case record_full_reg:
> >> +      return reg ().get_loc ();
> >> +    case record_full_mem:
> >> +      return mem ().get_loc ();
> >> +    }
> >> +    gdb_assert_not_reached ("Impossible entry type");  }
> >> +
> >> +  /* Execute this entry, swapping the appropriate values from memory or
> >> +     register and the recorded ones.  Returns TRUE if the execution was
> >> +     stopped by a watchpoint.  */
> >> +
> >> +  bool execute (regcache *regcache)
> >> +  {
> >> +    switch (type ())
> >> +      {
> >> +      case record_full_reg:
> >> +	return reg ().execute (regcache);
> >> +      case record_full_mem:
> >> +	return mem ().execute (regcache->arch ());
> >> +      }
> >> +    return false;
> >> +  }
> >>   };
> >>
> >>   /* This is the main structure that comprises the execution log.
> >> @@ -386,91 +627,12 @@ static struct cmd_list_element
> >> *record_full_cmdlist;  static void record_full_goto_insn (size_t target_insn,
> >>   				   enum exec_direction_kind dir);
> >>
> >> -/* Initialization and cleanup functions for record_full_reg and
> >> -   record_full_mem entries.  */
> >> -
> >> -/* Init a record_full_reg record entry.  */
> >> -
> >> -static inline record_full_entry
> >> -record_full_reg_init (struct regcache *regcache, int regnum) -{
> >> -  record_full_entry rec;
> >> -  struct gdbarch *gdbarch = regcache->arch ();
> >> -
> >> -  rec.type = record_full_reg;
> >> -  rec.u.reg.num = regnum;
> >> -  rec.u.reg.len = register_size (gdbarch, regnum);
> >> -  if (rec.u.reg.len > sizeof (rec.u.reg.u.buf))
> >> -    rec.u.reg.u.ptr = (gdb_byte *) xmalloc (rec.u.reg.len);
> >> -
> >> -  return rec;
> >> -}
> >> -
> >> -/* Cleanup a record_full_reg record entry.  */
> >> -
> >> -static inline void
> >> -record_full_reg_cleanup (record_full_entry rec) -{
> >> -  gdb_assert (rec.type == record_full_reg);
> >> -  if (rec.u.reg.len > sizeof (rec.u.reg.u.buf))
> >> -    xfree (rec.u.reg.u.ptr);
> >> -}
> >> -
> >> -/* Init a record_full_mem record entry.  */
> >> -
> >> -static inline record_full_entry
> >> -record_full_mem_init (CORE_ADDR addr, int len) -{
> >> -  record_full_entry rec;
> >> -
> >> -  rec.type = record_full_mem;
> >> -  rec.u.mem.addr = addr;
> >> -  rec.u.mem.len = len;
> >> -  if (rec.u.mem.len > sizeof (rec.u.mem.u.buf))
> >> -    rec.u.mem.u.ptr = (gdb_byte *) xmalloc (len);
> >> -  rec.u.mem.mem_entry_not_accessible = 0;
> >> -
> >> -  return rec;
> >> -}
> >> -
> >> -/* Cleanup a record_full_mem record entry.  */
> >> -
> >> -static inline void
> >> -record_full_mem_cleanup (record_full_entry rec) -{
> >> -  gdb_assert (rec.type == record_full_mem);
> >> -  if (rec.u.mem.len > sizeof (rec.u.mem.u.buf))
> >> -    xfree (rec.u.mem.u.ptr);
> >> -}
> >> -
> >> -/* Free one record entry, any type.  */
> >> -
> >> -static inline void
> >> -record_full_entry_cleanup (record_full_entry rec) -{
> >> -
> >> -  switch (rec.type) {
> >> -  case record_full_reg:
> >> -    record_full_reg_cleanup (rec);
> >> -    break;
> >> -  case record_full_mem:
> >> -    record_full_mem_cleanup (rec);
> >> -    break;
> >> -  }
> >> -}
> >> -
> >>   static void
> >>   record_full_reset_history ()
> >>   {
> >>     record_full_insn_count = 0;
> >>     record_full_next_insn = 0;
> >>
> >> -  for (auto &insn : record_full_list)
> >> -    {
> >> -      for (auto &entry : insn.effects)
> >> -	record_full_entry_cleanup (entry);
> >> -    }
> >> -
> >>     record_full_list.clear ();
> >>   }
> >>
> >> @@ -480,11 +642,7 @@ static void
> >>   record_full_list_release_following (int index)  {
> >>     for (int i = record_full_list.size () - 1; i > index; i--)
> >> -    {
> >> -      for (auto &entry : record_full_list[i].effects)
> >> -	record_full_entry_cleanup (entry);
> >> -      record_full_list.pop_back ();
> >> -    }
> >> +    record_full_list.pop_back ();
> >>     /* Set the next instruction to be past the end of the log so we
> >>        start recording if the user moves forward again.  */
> >>     record_full_next_insn = index;
> >> @@ -513,9 +671,6 @@ record_full_list_release_first (void)
> >>     if (record_full_list.empty ())
> >>       return;
> >>
> >> -  for (auto &entry : record_full_list[0].effects)
> >> -    record_full_entry_cleanup (entry);
> >> -
> >>     record_full_list.pop_front ();
> >>     --record_full_next_insn;
> >>   }
> >> @@ -525,28 +680,7 @@ record_full_list_release_first (void)  static
> >> void record_full_arch_list_add (record_full_entry &rec)  {
> >> -  record_full_incomplete_instruction.effects.push_back (rec); -}
> >> -
> >> -/* Return the value storage location of a record entry.  */ -static
> >> inline gdb_byte * -record_full_get_loc (struct record_full_entry
> >> *rec) -{
> >> -  switch (rec->type) {
> >> -  case record_full_mem:
> >> -    if (rec->u.mem.len > sizeof (rec->u.mem.u.buf))
> >> -      return rec->u.mem.u.ptr;
> >> -    else
> >> -      return rec->u.mem.u.buf;
> >> -  case record_full_reg:
> >> -    if (rec->u.reg.len > sizeof (rec->u.reg.u.buf))
> >> -      return rec->u.reg.u.ptr;
> >> -    else
> >> -      return rec->u.reg.u.buf;
> >> -  default:
> >> -    gdb_assert_not_reached ("unexpected record_full_entry type");
> >> -    return NULL;
> >> -  }
> >> +  record_full_incomplete_instruction.effects.push_back (std::move
> >> + (rec));
> >>   }
> >>
> >>   /* Record the value of a register NUM to record_full_arch_list.  */
> >> @@ -554,7
> >> +688,7 @@ record_full_get_loc (struct record_full_entry *rec)  int
> >> record_full_arch_list_add_reg (struct regcache *regcache, int regnum)
> >> {
> >> -  record_full_entry rec;
> >> +  record_full_entry rec (record_full_reg, regcache->arch (),
> >> + regnum);
> >>
> >>     if (record_debug > 1)
> >>       gdb_printf (gdb_stdlog,
> >> @@ -562,9 +696,7 @@ record_full_arch_list_add_reg (struct regcache
> >> *regcache, int regnum)
> >>   		"record list.\n",
> >>   		regnum);
> >>
> >> -  rec = record_full_reg_init (regcache, regnum);
> >> -
> >> -  regcache->cooked_read (regnum, record_full_get_loc (&rec));
> >> +  regcache->cooked_read (regnum, rec.get_loc ());
> >>
> >>     record_full_arch_list_add (rec);
> >>
> >> @@ -577,7 +709,7 @@ record_full_arch_list_add_reg (struct regcache
> >> *regcache, int regnum)  int  record_full_arch_list_add_mem (CORE_ADDR
> >> addr, int len)  {
> >> -  record_full_entry rec;
> >> +  record_full_entry rec (record_full_mem, addr, len);
> >>
> >>     if (record_debug > 1)
> >>       gdb_printf (gdb_stdlog,
> >> @@ -588,14 +720,9 @@ record_full_arch_list_add_mem (CORE_ADDR
> addr,
> >> int len)
> >>     if (!addr)	/* FIXME: Why?  Some arch must permit it...  */
> >>       return 0;
> >>
> >> -  rec = record_full_mem_init (addr, len);
> >> -
> >>     if (record_read_memory (current_inferior ()->arch (), addr,
> >> -			  record_full_get_loc (&rec), len))
> >> -    {
> >> -      record_full_mem_cleanup (rec);
> >> -      return -1;
> >> -    }
> >> +			  rec.get_loc (), len))
> >> +    return -1;
> >>
> >>     record_full_arch_list_add (rec);
> >>
> >> @@ -723,91 +850,6 @@ record_full_gdb_operation_disable_set (void)
> >> static enum target_stop_reason record_full_stop_reason
> >>     = TARGET_STOPPED_BY_NO_REASON;
> >>
> >> -/* Execute one instruction from the record log.  Each instruction in
> >> -   the log will be represented by an arbitrary sequence of register
> >> -   entries and memory entries, followed by an 'end' entry.  */
> >> -
> >> -static inline void
> >> -record_full_exec_entry (regcache *regcache,
> >> -			gdbarch *gdbarch,
> >> -			record_full_entry *entry)
> >> -{
> >> -  switch (entry->type)
> >> -    {
> >> -    case record_full_reg: /* reg */
> >> -      {
> >> -	gdb::byte_vector reg (entry->u.reg.len);
> >> -
> >> -	if (record_debug > 1)
> >> -	  gdb_printf (gdb_stdlog,
> >> -		      "Process record: record_full_reg %s to "
> >> -		      "inferior num = %d.\n",
> >> -		      host_address_to_string (entry),
> >> -		      entry->u.reg.num);
> >> -
> >> -	regcache->cooked_read (entry->u.reg.num, reg.data ());
> >> -	regcache->cooked_write (entry->u.reg.num, record_full_get_loc
> >> (entry));
> >> -	memcpy (record_full_get_loc (entry), reg.data (), entry->u.reg.len);
> >> -      }
> >> -      break;
> >> -
> >> -    case record_full_mem: /* mem */
> >> -      {
> >> -	/* Nothing to do if the entry is flagged not_accessible.  */
> >> -	if (!entry->u.mem.mem_entry_not_accessible)
> >> -	  {
> >> -	    gdb::byte_vector mem (entry->u.mem.len);
> >> -
> >> -	    if (record_debug > 1)
> >> -	      gdb_printf (gdb_stdlog,
> >> -			  "Process record: record_full_mem %s to "
> >> -			  "inferior addr = %s len = %d.\n",
> >> -			  host_address_to_string (entry),
> >> -			  paddress (gdbarch, entry->u.mem.addr),
> >> -			  entry->u.mem.len);
> >> -
> >> -	    if (record_read_memory (gdbarch,
> >> -				    entry->u.mem.addr, mem.data (),
> >> -				    entry->u.mem.len))
> >> -	      entry->u.mem.mem_entry_not_accessible = 1;
> >> -	    else
> >> -	      {
> >> -		if (target_write_memory (entry->u.mem.addr,
> >> -					 record_full_get_loc (entry),
> >> -					 entry->u.mem.len))
> >> -		  {
> >> -		    entry->u.mem.mem_entry_not_accessible = 1;
> >> -		    if (record_debug)
> >> -		      warning (_("Process record: error writing memory at "
> >> -				 "addr = %s len = %d."),
> >> -			       paddress (gdbarch, entry->u.mem.addr),
> >> -			       entry->u.mem.len);
> >> -		  }
> >> -		else
> >> -		  {
> >> -		    memcpy (record_full_get_loc (entry), mem.data (),
> >> -			    entry->u.mem.len);
> >> -
> >> -		    /* We've changed memory --- check if a hardware
> >> -		       watchpoint should trap.  Note that this
> >> -		       presently assumes the target beneath supports
> >> -		       continuable watchpoints.  On non-continuable
> >> -		       watchpoints target, we'll want to check this
> >> -		       _before_ actually doing the memory change, and
> >> -		       not doing the change at all if the watchpoint
> >> -		       traps.  */
> >> -		    if (hardware_watchpoint_inserted_in_range
> >> -			(current_inferior ()->aspace.get (),
> >> -			 entry->u.mem.addr, entry->u.mem.len))
> >> -		      record_full_stop_reason =
> >> TARGET_STOPPED_BY_WATCHPOINT;
> >> -		  }
> >> -	      }
> >> -	  }
> >> -      }
> >> -      break;
> >> -    }
> >> -}
> >> -
> >>   /* Execute one entry in the log by executing all the effects.  */
> >>
> >>   static inline void
> >> @@ -816,7 +858,8 @@ record_full_exec_insn (regcache *regcache,
> >>   		       record_full_instruction &insn)  {
> >>     for (auto &entry : insn.effects)
> >> -    record_full_exec_entry (regcache, gdbarch, &entry);
> >> +    if (entry.execute (regcache))
> >> +      record_full_stop_reason = TARGET_STOPPED_BY_WATCHPOINT;
> >>   }
> >>
> >>   static void record_full_restore (struct bfd &cbfd); @@ -2193,21
> >> +2236,19 @@ record_full_read_entry_from_bfd (bfd *cbfd, asection
> >> *osec, int
> >> *bfd_offset)
> >>   	bfdcore_read (cbfd, osec, &regnum, sizeof (regnum), bfd_offset);
> >>   	regnum = netorder32 (regnum);
> >>
> >> -	record_full_entry rec;
> >> -
> >> -	rec = record_full_reg_init (cache, regnum);
> >> +	record_full_entry rec (record_full_reg, cache->arch (), regnum);
> >>
> >>   	/* Get val.  */
> >> -	bfdcore_read (cbfd, osec, record_full_get_loc (&rec),
> >> -		      rec.u.reg.len, bfd_offset);
> >> +	bfdcore_read (cbfd, osec, rec.get_loc (),
> >> +		      rec.reg ().len, bfd_offset);
> >>
> >>   	if (record_debug)
> >>   	  gdb_printf (gdb_stdlog,
> >>   		      "  Reading register %d (1 "
> >>   		      "plus %lu plus %d bytes)\n",
> >> -		      rec.u.reg.num,
> >> +		      rec.reg ().num,
> >>   		      (unsigned long) sizeof (regnum),
> >> -		      rec.u.reg.len);
> >> +		      rec.reg ().len);
> >>
> >>   	record_full_arch_list_add (rec);
> >>   	break;
> >> @@ -2223,22 +2264,20 @@ record_full_read_entry_from_bfd (bfd *cbfd,
> >> asection *osec, int *bfd_offset)
> >>   	bfdcore_read (cbfd, osec, &addr, sizeof (addr), bfd_offset);
> >>   	addr = netorder64 (addr);
> >>
> >> -	record_full_entry rec;
> >> -	rec = record_full_mem_init (addr, len);
> >> +	record_full_entry rec (record_full_mem, addr, len);
> >>
> >>   	/* Get val.  */
> >> -	bfdcore_read (cbfd, osec, record_full_get_loc (&rec),
> >> -		      len, bfd_offset);
> >> +	bfdcore_read (cbfd, osec, rec.get_loc (), len, bfd_offset);
> >>
> >>   	if (record_debug)
> >>   	  gdb_printf (gdb_stdlog,
> >>   		      "  Reading memory %s (1 plus "
> >>   		      "%lu plus %lu plus %d bytes)\n",
> >>   		      paddress (get_current_arch (),
> >> -				rec.u.mem.addr),
> >> +				rec.mem ().addr),
> >>   		      (unsigned long) sizeof (addr),
> >>   		      (unsigned long) sizeof (len),
> >> -		      rec.u.mem.len);
> >> +		      rec.mem ().len);
> >>
> >>   	record_full_arch_list_add (rec);
> >>   	break;
> >> @@ -2385,57 +2424,56 @@ record_full_write_entry_to_bfd
> >> (record_full_entry &entry,
> >>     uint32_t regnum, len;
> >>     uint64_t addr;
> >>
> >> -  type = entry.type;
> >> +  type = entry.type ();
> >>     bfdcore_write (obfd.get (), osec, &type, sizeof (type),
> >> bfd_offset);
> >>
> >> -  switch (entry.type)
> >> +  switch (type)
> >>       {
> >>       case record_full_reg: /* reg */
> >> -      if (record_debug)
> >> -	gdb_printf (gdb_stdlog,
> >> -		    "  Writing register %d (1 "
> >> -		    "plus %lu plus %d bytes)\n",
> >> -		    entry.u.reg.num,
> >> -		    (unsigned long) sizeof (regnum),
> >> -		    entry.u.reg.len);
> >> -
> >> -      /* Write regnum.  */
> >> -      regnum = netorder32 (entry.u.reg.num);
> >> -      bfdcore_write (obfd.get (), osec, &regnum,
> >> -		     sizeof (regnum), bfd_offset);
> >> -
> >> -      /* Write regval.  */
> >> -      bfdcore_write (obfd.get (), osec,
> >> -		     record_full_get_loc (&entry),
> >> -		     entry.u.reg.len, bfd_offset);
> >> -      break;
> >> +      {
> >> +	auto &reg = entry.reg ();
> >> +	if (record_debug)
> >> +	  gdb_printf (gdb_stdlog,
> >> +		      "  Writing register %d (1 "
> >> +		      "plus %lu plus %d bytes)\n",
> >> +		      reg.num,
> >> +		      (unsigned long) sizeof (regnum),
> >> +		      reg.len);
> >> +
> >> +	/* Write regnum.  */
> >> +	regnum = netorder32 (reg.num);
> >> +	bfdcore_write (obfd.get (), osec, &regnum, sizeof (regnum),
> >> +bfd_offset);
> >> +
> >> +	/* Write regval.  */
> >> +	bfdcore_write (obfd.get (), osec, entry.get_loc (), reg.len, bfd_offset);
> >> +	break;
> >> +      }
> >>
> >>       case record_full_mem: /* mem */
> >> -      if (record_debug)
> >> -	gdb_printf (gdb_stdlog,
> >> -		    "  Writing memory %s (1 plus "
> >> -		    "%lu plus %lu plus %d bytes)\n",
> >> -		    paddress (gdbarch,
> >> -			      entry.u.mem.addr),
> >> -		    (unsigned long) sizeof (addr),
> >> -		    (unsigned long) sizeof (len),
> >> -		    entry.u.mem.len);
> >> -
> >> -      /* Write memlen.  */
> >> -      len = netorder32 (entry.u.mem.len);
> >> -      bfdcore_write (obfd.get (), osec, &len, sizeof (len),
> >> -		     bfd_offset);
> >> -
> >> -      /* Write memaddr.  */
> >> -      addr = netorder64 (entry.u.mem.addr);
> >> -      bfdcore_write (obfd.get (), osec, &addr,
> >> -		     sizeof (addr), bfd_offset);
> >> -
> >> -      /* Write memval.  */
> >> -      bfdcore_write (obfd.get (), osec,
> >> -		     record_full_get_loc (&entry),
> >> -		     entry.u.mem.len, bfd_offset);
> >> -      break;
> >> +      {
> >> +	auto &mem = entry.mem ();
> >> +	if (record_debug)
> >> +	  gdb_printf (gdb_stdlog,
> >> +		      "  Writing memory %s (1 plus "
> >> +		      "%lu plus %lu plus %d bytes)\n",
> >> +		      paddress (gdbarch, mem.addr),
> >> +		      (unsigned long) sizeof (addr),
> >> +		      (unsigned long) sizeof (len),
> >> +		      mem.len);
> >> +
> >> +	/* Write memlen.  */
> >> +	len = netorder32 (mem.len);
> >> +	bfdcore_write (obfd.get (), osec, &len, sizeof (len), bfd_offset);
> >> +
> >> +	/* Write memaddr.  */
> >> +	addr = netorder64 (mem.addr);
> >> +	bfdcore_write (obfd.get (), osec, &addr, sizeof (addr),
> >> +bfd_offset);
> >> +
> >> +	/* Write memval.  */
> >> +	bfdcore_write (obfd.get (), osec, entry.get_loc (), mem.len,
> >> +		       bfd_offset);
> >> +	break;
> >> +      }
> >>       }
> >>   }
> >>
> >> @@ -2482,13 +2520,13 @@ record_full_base_target::save_record (const
> >> char *recfilename)
> >>         /* Number of effects of an instruction.  */
> >>         save_size += sizeof (uint32_t) + sizeof (uint8_t) + sizeof (uint32_t);
> >>         for (auto &entry : record_full_list[i].effects)
> >> -	switch (entry.type)
> >> +	switch (entry.type ())
> >>   	  {
> >>   	  case record_full_reg:
> >> -	    save_size += 1 + 4 + entry.u.reg.len;
> >> +	    save_size += 1 + 4 + entry.reg ().len;
> >>   	    break;
> >>   	  case record_full_mem:
> >> -	    save_size += 1 + 4 + 8 + entry.u.mem.len;
> >> +	    save_size += 1 + 4 + 8 + entry.mem ().len;
> >>   	    break;
> >>   	  }
> >>       }
> >> @@ -2621,18 +2659,18 @@ maintenance_print_record_instruction
> (const
> >> char *args, int from_tty)
> >>
> >>     gdbarch *arch = current_inferior ()->arch ();
> >>
> >> -  for (auto entry : to_print->effects)
> >> +  for (auto &entry : to_print->effects)
> >>       {
> >> -      switch (entry.type)
> >> +      switch (entry.type ())
> >>   	{
> >>   	  case record_full_reg:
> >>   	    {
> >> -	      type *regtype = gdbarch_register_type (arch, entry.u.reg.num);
> >> +	      type *regtype = gdbarch_register_type (arch, entry.reg
> >> +().num);
> >>   	      value *val
> >>   		  = value_from_contents (regtype,
> >> -					 record_full_get_loc (&entry));
> >> +					 entry.get_loc ());
> >>   	      gdb_printf ("Register %s changed: ",
> >> -			  gdbarch_register_name (arch, entry.u.reg.num));
> >> +			  gdbarch_register_name (arch, entry.reg ().num));
> >>   	      struct value_print_options opts;
> >>   	      get_user_print_options (&opts);
> >>   	      opts.raw = true;
> >> @@ -2642,11 +2680,12 @@ maintenance_print_record_instruction
> (const
> >> char *args, int from_tty)
> >>   	    }
> >>   	  case record_full_mem:
> >>   	    {
> >> -	      gdb_byte *b = record_full_get_loc (&entry);
> >> +	      record_full_mem_entry& mem = entry.mem ();
> >> +	      gdb_byte *b = entry.get_loc ();
> >>   	      gdb_printf ("%d bytes of memory at address %s changed from:",
> >> -			  entry.u.mem.len,
> >> -			  print_core_address (arch, entry.u.mem.addr));
> >> -	      for (int i = 0; i < entry.u.mem.len; i++)
> >> +			  mem.len,
> >> +			  print_core_address (arch, mem.addr));
> >> +	      for (int i = 0; i < mem.len; i++)
> >>   		gdb_printf (" %02x", b[i]);
> >>   	      gdb_printf ("\n");
> >>   	      break;
> >> --
> >> 2.54.0
> >>
> > It seems that you did not change the code as discussed here:
> > https://sourceware.org/pipermail/gdb-patches/2026-May/227699.html
> >
> > Would you mind sharing the reason for that?
> > In my opinion this is necessary.
> 
> I blame the weekend. Leave on friday thinking "I'll do it on monday", arrive
> on monday thinking "I did it last friday".
> 
> I made sure to make the change now. Added the asserts that the length is
> 0 in the move operator, which means we won't need to worry about freeing
> the memory.

But isn't it possible that "len > sizeof (u.buf)" or at least "len > 0" at this point ?

So before this code:

>>>> +    addr = other.addr;
>>>> +    len = other.len;
>>>> +    memcpy (u.buf, other.u.buf, sizeof (u.buf));

Christina
Intel Deutschland GmbH

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