[PATCH 11/13] gdb: remove some uses of alloca from remote.c

[Andrew Burgess <aburgess@redhat.com>]

Remove some of the uses of alloca from remote.c and replace them with
either gdb::byte_vector or std::vector<gdb_byte>.

In one case I've used std::vector<gdb_byte> because this handles
automatically zeroing the contents, and this allows me to remove an
associated memset.

There are other uses of alloca in this file (remote.c), but these are
all for types other than gdb_byte so need replacing with something
other than gdb::byte_vector.

There should be no user visible changes after this commit.
---
 gdb/remote.c | 40 ++++++++++++++++++----------------------
 1 file changed, 18 insertions(+), 22 deletions(-)

diff --git a/gdb/remote.c b/gdb/remote.c
index ba7a7520cb4..3f0552e7c9e 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -8554,7 +8554,6 @@ remote_target::fetch_register_using_p (struct regcache *regcache,
   struct gdbarch *gdbarch = regcache->arch ();
   struct remote_state *rs = get_remote_state ();
   char *buf, *p;
-  gdb_byte *regp = (gdb_byte *) alloca (register_size (gdbarch, reg->regnum));
   int i;
 
   if (m_features.packet_support (PACKET_p) == PACKET_DISABLE)
@@ -8593,6 +8592,7 @@ remote_target::fetch_register_using_p (struct regcache *regcache,
     }
 
   /* Otherwise, parse and supply the value.  */
+  gdb::byte_vector regp (register_size (gdbarch, reg->regnum));
   p = buf;
   i = 0;
   while (p[0] != 0)
@@ -8603,7 +8603,7 @@ remote_target::fetch_register_using_p (struct regcache *regcache,
       regp[i++] = fromhex (p[0]) * 16 + fromhex (p[1]);
       p += 2;
     }
-  regcache->raw_supply (reg->regnum, regp);
+  regcache->raw_supply (reg->regnum, regp.data ());
   return 1;
 }
 
@@ -8862,7 +8862,7 @@ remote_target::store_register_using_P (const struct regcache *regcache,
   struct remote_state *rs = get_remote_state ();
   /* Try storing a single register.  */
   char *buf = rs->buf.data ();
-  gdb_byte *regp = (gdb_byte *) alloca (register_size (gdbarch, reg->regnum));
+  gdb::byte_vector regp (register_size (gdbarch, reg->regnum));
   char *p;
 
   if (m_features.packet_support (PACKET_P) == PACKET_DISABLE)
@@ -8873,8 +8873,8 @@ remote_target::store_register_using_P (const struct regcache *regcache,
 
   xsnprintf (buf, get_remote_packet_size (), "P%s=", phex_nz (reg->pnum, 0));
   p = buf + strlen (buf);
-  regcache->raw_collect (reg->regnum, regp);
-  bin2hex (regp, p, register_size (gdbarch, reg->regnum));
+  regcache->raw_collect (reg->regnum, regp.data ());
+  bin2hex (regp.data (), p, register_size (gdbarch, reg->regnum));
   putpkt (rs->buf);
   getpkt (&rs->buf, 0);
 
@@ -8900,30 +8900,26 @@ remote_target::store_registers_using_G (const struct regcache *regcache)
 {
   struct remote_state *rs = get_remote_state ();
   remote_arch_state *rsa = rs->get_remote_arch_state (regcache->arch ());
-  gdb_byte *regs;
-  char *p;
 
-  /* Extract all the registers in the regcache copying them into a
-     local buffer.  */
-  {
-    int i;
+  /* Extract all the registers in the REGCACHE copying them into a local
+     buffer REGS.
 
-    regs = (gdb_byte *) alloca (rsa->sizeof_g_packet);
-    memset (regs, 0, rsa->sizeof_g_packet);
-    for (i = 0; i < gdbarch_num_regs (regcache->arch ()); i++)
-      {
-	struct packet_reg *r = &rsa->regs[i];
+     Use std::vector<gdb_byte> here (instead of gdb::byte_vector) because
+     we want the contents to be zero initialized.  */
+  std::vector<gdb_byte> regs (rsa->sizeof_g_packet);
+  for (int i = 0; i < gdbarch_num_regs (regcache->arch ()); i++)
+    {
+      struct packet_reg *r = &rsa->regs[i];
 
-	if (r->in_g_packet)
-	  regcache->raw_collect (r->regnum, regs + r->offset);
-      }
-  }
+      if (r->in_g_packet)
+	regcache->raw_collect (r->regnum, regs.data () + r->offset);
+    }
 
   /* Command describes registers byte by byte,
      each byte encoded as two hex characters.  */
-  p = rs->buf.data ();
+  char *p = rs->buf.data ();
   *p++ = 'G';
-  bin2hex (regs, p, rsa->sizeof_g_packet);
+  bin2hex (regs.data (), p, rsa->sizeof_g_packet);
   putpkt (rs->buf);
   getpkt (&rs->buf, 0);
   if (packet_check_result (rs->buf) == PACKET_ERROR)
-- 
2.25.4