gdb: remove uses of VLA

Remove uses of VLAs, replace with gdb::byte_vector.  There might be more
in files that I can't compile, but it's difficult to tell without
actually compiling on all platforms.

Many thanks to the Linaro pre-commit CI for helping find some problems
with an earlier iteration of this patch.

Change-Id: I3e5e34fcac51f3e6b732bb801c77944e010b162e
Reviewed-by: Keith Seitz <keiths@redhat.com>

gdb/aarch64-linux-nat.c

@@ -496,12 +496,11 @@ fetch_tlsregs_from_thread (struct regcache *regcache)
   gdb_assert (regno != -1);
   gdb_assert (tdep->tls_register_count > 0);
 
-  uint64_t tpidrs[tdep->tls_register_count];
+  std::vector<uint64_t> tpidrs (tdep->tls_register_count);
-  memset(tpidrs, 0, sizeof(tpidrs));
 
   struct iovec iovec;
-  iovec.iov_base = tpidrs;
+  iovec.iov_base = tpidrs.data ();
-  iovec.iov_len = sizeof (tpidrs);
+  iovec.iov_len = tpidrs.size () * sizeof (tpidrs[0]);
 
   int tid = get_ptrace_pid (regcache->ptid ());
   if (ptrace (PTRACE_GETREGSET, tid, NT_ARM_TLS, &iovec) != 0)
@@ -524,8 +523,7 @@ store_tlsregs_to_thread (struct regcache *regcache)
   gdb_assert (regno != -1);
   gdb_assert (tdep->tls_register_count > 0);
 
-  uint64_t tpidrs[tdep->tls_register_count];
+  std::vector<uint64_t> tpidrs (tdep->tls_register_count);
-  memset(tpidrs, 0, sizeof(tpidrs));
 
   for (int i = 0; i < tdep->tls_register_count; i++)
     {
@@ -536,8 +534,8 @@ store_tlsregs_to_thread (struct regcache *regcache)
     }
 
   struct iovec iovec;
-  iovec.iov_base = &tpidrs;
+  iovec.iov_base = tpidrs.data ();
-  iovec.iov_len = sizeof (tpidrs);
+  iovec.iov_len = tpidrs.size () * sizeof (tpidrs[0]);
 
   int tid = get_ptrace_pid (regcache->ptid ());
   if (ptrace (PTRACE_SETREGSET, tid, NT_ARM_TLS, &iovec) != 0)

gdb/aarch64-linux-tdep.c

@@ -1298,8 +1298,7 @@ aarch64_linux_supply_za_regset (const struct regset *regset,
     }
   else
     {
-      gdb_byte za_zeroed[za_bytes];
+      gdb::byte_vector za_zeroed (za_bytes, 0);
-      memset (za_zeroed, 0, za_bytes);
       regcache->raw_supply (tdep->sme_za_regnum, za_zeroed);
     }
 }

gdb/aarch64-tdep.c

@@ -1728,16 +1728,15 @@ pass_in_v (struct gdbarch *gdbarch,
     {
       int regnum = AARCH64_V0_REGNUM + info->nsrn;
       /* Enough space for a full vector register.  */
-      gdb_byte reg[register_size (gdbarch, regnum)];
+      gdb::byte_vector reg (register_size (gdbarch, regnum), 0);
-      gdb_assert (len <= sizeof (reg));
+      gdb_assert (len <= reg.size ());
 
       info->argnum++;
       info->nsrn++;
 
-      memset (reg, 0, sizeof (reg));
       /* PCS C.1, the argument is allocated to the least significant
 	 bits of V register.  */
-      memcpy (reg, buf, len);
+      memcpy (reg.data (), buf, len);
       regcache->cooked_write (regnum, reg);
 
       aarch64_debug_printf ("arg %d in %s", info->argnum,
@@ -2544,8 +2543,8 @@ aarch64_extract_return_value (struct type *type, struct regcache *regs,
 	{
 	  int regno = AARCH64_V0_REGNUM + i;
 	  /* Enough space for a full vector register.  */
-	  gdb_byte buf[register_size (gdbarch, regno)];
+	  gdb::byte_vector buf (register_size (gdbarch, regno));
-	  gdb_assert (len <= sizeof (buf));
+	  gdb_assert (len <= buf.size ());
 
 	  aarch64_debug_printf
 	    ("read HFA or HVA return value element %d from %s",
@@ -2553,7 +2552,7 @@ aarch64_extract_return_value (struct type *type, struct regcache *regs,
 
 	  regs->cooked_read (regno, buf);
 
-	  memcpy (valbuf, buf, len);
+	  memcpy (valbuf, buf.data (), len);
 	  valbuf += len;
 	}
     }
@@ -2658,8 +2657,8 @@ aarch64_store_return_value (struct type *type, struct regcache *regs,
 	{
 	  int regno = AARCH64_V0_REGNUM + i;
 	  /* Enough space for a full vector register.  */
-	  gdb_byte tmpbuf[register_size (gdbarch, regno)];
+	  gdb::byte_vector tmpbuf (register_size (gdbarch, regno));
-	  gdb_assert (len <= sizeof (tmpbuf));
+	  gdb_assert (len <= tmpbuf.size ());
 
 	  aarch64_debug_printf
 	    ("write HFA or HVA return value element %d to %s",
@@ -2670,7 +2669,7 @@ aarch64_store_return_value (struct type *type, struct regcache *regs,
 	     original contents of the register before overriding it with a new
 	     value that has a potential size <= 16 bytes.  */
 	  regs->cooked_read (regno, tmpbuf);
-	  memcpy (tmpbuf, valbuf,
+	  memcpy (tmpbuf.data (), valbuf,
 		  len > V_REGISTER_SIZE ? V_REGISTER_SIZE : len);
 	  regs->cooked_write (regno, tmpbuf);
 	  valbuf += len;
@@ -3303,18 +3302,16 @@ aarch64_pseudo_write_1 (gdbarch *gdbarch, const frame_info_ptr &next_frame,
 {
   unsigned raw_regnum = AARCH64_V0_REGNUM + regnum_offset;
 
-  /* Enough space for a full vector register.  */
+  /* Enough space for a full vector register.
-  int raw_reg_size = register_size (gdbarch, raw_regnum);
-  gdb_byte raw_buf[raw_reg_size];
-  static_assert (AARCH64_V0_REGNUM == AARCH64_SVE_Z0_REGNUM);
 
-  /* Ensure the register buffer is zero, we want gdb writes of the
+     Ensure the register buffer is zero, we want gdb writes of the
      various 'scalar' pseudo registers to behavior like architectural
      writes, register width bytes are written the remainder are set to
      zero.  */
-  memset (raw_buf, 0, register_size (gdbarch, AARCH64_V0_REGNUM));
+  gdb::byte_vector raw_buf (register_size (gdbarch, raw_regnum), 0);
+  static_assert (AARCH64_V0_REGNUM == AARCH64_SVE_Z0_REGNUM);
 
-  gdb::array_view<gdb_byte> raw_view (raw_buf, raw_reg_size);
+  gdb::array_view<gdb_byte> raw_view (raw_buf);
   copy (buf, raw_view.slice (0, buf.size ()));
   put_frame_register (next_frame, raw_regnum, raw_view);
 }

gdb/amd64-linux-nat.c

@@ -235,22 +235,21 @@ amd64_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum)
 
       if (have_ptrace_getregset == TRIBOOL_TRUE)
 	{
-	  char xstateregs[tdep->xsave_layout.sizeof_xsave];
-	  struct iovec iov;
-
 	  /* Pre-4.14 kernels have a bug (fixed by commit 0852b374173b
 	     "x86/fpu: Add FPU state copying quirk to handle XRSTOR failure on
 	     Intel Skylake CPUs") that sometimes causes the mxcsr location in
 	     xstateregs not to be copied by PTRACE_GETREGSET.  Make sure that
 	     the location is at least initialized with a defined value.  */
-	  memset (xstateregs, 0, sizeof (xstateregs));
+	  gdb::byte_vector xstateregs (tdep->xsave_layout.sizeof_xsave, 0);
-	  iov.iov_base = xstateregs;
+	  struct iovec iov;
-	  iov.iov_len = sizeof (xstateregs);
+
+	  iov.iov_base = xstateregs.data ();
+	  iov.iov_len = xstateregs.size ();
 	  if (ptrace (PTRACE_GETREGSET, tid,
 		      (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 	    perror_with_name (_("Couldn't get extended state status"));
 
-	  amd64_supply_xsave (regcache, -1, xstateregs);
+	  amd64_supply_xsave (regcache, -1, xstateregs.data ());
 	}
       else
 	{
@@ -300,16 +299,16 @@ amd64_linux_nat_target::store_registers (struct regcache *regcache, int regnum)
 
       if (have_ptrace_getregset == TRIBOOL_TRUE)
 	{
-	  char xstateregs[tdep->xsave_layout.sizeof_xsave];
+	  gdb::byte_vector xstateregs (tdep->xsave_layout.sizeof_xsave);
 	  struct iovec iov;
 
-	  iov.iov_base = xstateregs;
+	  iov.iov_base = xstateregs.data ();
-	  iov.iov_len = sizeof (xstateregs);
+	  iov.iov_len = xstateregs.size ();
 	  if (ptrace (PTRACE_GETREGSET, tid,
 		      (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)
 	    perror_with_name (_("Couldn't get extended state status"));
 
-	  amd64_collect_xsave (regcache, regnum, xstateregs, 0);
+	  amd64_collect_xsave (regcache, regnum, xstateregs.data (), 0);
 
 	  if (ptrace (PTRACE_SETREGSET, tid,
 		      (unsigned int) NT_X86_XSTATE, (long) &iov) < 0)

gdb/fbsd-tdep.c

@@ -2034,21 +2034,23 @@ fbsd_get_thread_local_address (struct gdbarch *gdbarch, CORE_ADDR dtv_addr,
 {
   LONGEST tls_index = fbsd_get_tls_index (gdbarch, lm_addr);
 
-  gdb_byte buf[gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT];
+  gdb::byte_vector buf (gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT);
-  if (target_read_memory (dtv_addr, buf, sizeof buf) != 0)
+  if (target_read_memory (dtv_addr, buf.data (), buf.size ()) != 0)
     throw_error (TLS_GENERIC_ERROR,
 		 _("Cannot find thread-local variables on this target"));
 
   const struct builtin_type *builtin = builtin_type (gdbarch);
-  CORE_ADDR addr = gdbarch_pointer_to_address (gdbarch,
+  CORE_ADDR addr
-					       builtin->builtin_data_ptr, buf);
+    = gdbarch_pointer_to_address (gdbarch, builtin->builtin_data_ptr,
+				  buf.data ());
 
   addr += (tls_index + 1) * builtin->builtin_data_ptr->length ();
-  if (target_read_memory (addr, buf, sizeof buf) != 0)
+  if (target_read_memory (addr, buf.data (), buf.size ()) != 0)
     throw_error (TLS_GENERIC_ERROR,
 		 _("Cannot find thread-local variables on this target"));
 
-  addr = gdbarch_pointer_to_address (gdbarch, builtin->builtin_data_ptr, buf);
+  addr = gdbarch_pointer_to_address (gdbarch, builtin->builtin_data_ptr,
+				     buf.data ());
   return addr + offset;
 }
 

gdb/i386-linux-nat.c

@@ -315,19 +315,19 @@ fetch_xstateregs (struct regcache *regcache, int tid)
 {
   struct gdbarch *gdbarch = regcache->arch ();
   const i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (gdbarch);
-  char xstateregs[tdep->xsave_layout.sizeof_xsave];
+  gdb::byte_vector xstateregs (tdep->xsave_layout.sizeof_xsave);
   struct iovec iov;
 
   if (have_ptrace_getregset != TRIBOOL_TRUE)
     return 0;
 
-  iov.iov_base = xstateregs;
+  iov.iov_base = xstateregs.data ();
-  iov.iov_len = sizeof(xstateregs);
+  iov.iov_len = xstateregs.size ();
   if (ptrace (PTRACE_GETREGSET, tid, (unsigned int) NT_X86_XSTATE,
 	      &iov) < 0)
     perror_with_name (_("Couldn't read extended state status"));
 
-  i387_supply_xsave (regcache, -1, xstateregs);
+  i387_supply_xsave (regcache, -1, xstateregs.data ());
   return 1;
 }
 
@@ -340,19 +340,19 @@ store_xstateregs (const struct regcache *regcache, int tid, int regno)
 {
   struct gdbarch *gdbarch = regcache->arch ();
   const i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (gdbarch);
-  char xstateregs[tdep->xsave_layout.sizeof_xsave];
+  gdb::byte_vector xstateregs (tdep->xsave_layout.sizeof_xsave);
   struct iovec iov;
 
   if (have_ptrace_getregset != TRIBOOL_TRUE)
     return 0;
-  
+
-  iov.iov_base = xstateregs;
+  iov.iov_base = xstateregs.data ();
-  iov.iov_len = sizeof(xstateregs);
+  iov.iov_len = xstateregs.size ();
   if (ptrace (PTRACE_GETREGSET, tid, (unsigned int) NT_X86_XSTATE,
 	      &iov) < 0)
     perror_with_name (_("Couldn't read extended state status"));
 
-  i387_collect_xsave (regcache, regno, xstateregs, 0);
+  i387_collect_xsave (regcache, regno, xstateregs.data (), 0);
 
   if (ptrace (PTRACE_SETREGSET, tid, (unsigned int) NT_X86_XSTATE,
 	      (int) &iov) < 0)

gdb/loongarch-tdep.c

@@ -36,14 +36,14 @@ static insn_t
 loongarch_fetch_instruction (CORE_ADDR pc)
 {
   size_t insn_len = loongarch_insn_length (0);
-  gdb_byte buf[insn_len];
+  gdb::byte_vector buf (insn_len);
   int err;
 
-  err = target_read_memory (pc, buf, insn_len);
+  err = target_read_memory (pc, buf.data (), insn_len);
   if (err)
     memory_error (TARGET_XFER_E_IO, pc);
 
-  return extract_unsigned_integer (buf, insn_len, BFD_ENDIAN_LITTLE);
+  return extract_unsigned_integer (buf.data (), insn_len, BFD_ENDIAN_LITTLE);
 }
 
 /* Return TRUE if INSN is a unconditional branch instruction, otherwise return FALSE.  */
@@ -1306,18 +1306,24 @@ loongarch_return_value (struct gdbarch *gdbarch, struct value *function,
 	   and the signed integer scalars are sign-extended.  */
 	if (writebuf)
 	  {
-	    gdb_byte buf[regsize];
+	    gdb::byte_vector buf (regsize);
 	    if (type->is_unsigned ())
 	      {
-		ULONGEST data = extract_unsigned_integer (writebuf, len, BFD_ENDIAN_LITTLE);
+		ULONGEST data = extract_unsigned_integer (writebuf, len,
-		store_unsigned_integer (buf, regsize, BFD_ENDIAN_LITTLE, data);
+							  BFD_ENDIAN_LITTLE);
+		store_unsigned_integer (buf.data (), regsize,
+					BFD_ENDIAN_LITTLE, data);
 	      }
 	    else
 	      {
-		LONGEST data = extract_signed_integer (writebuf, len, BFD_ENDIAN_LITTLE);
+		LONGEST data
-		store_signed_integer (buf, regsize, BFD_ENDIAN_LITTLE, data);
+		  = extract_signed_integer (writebuf, len, BFD_ENDIAN_LITTLE);
+		store_signed_integer (buf.data (), regsize, BFD_ENDIAN_LITTLE,
+				      data);
 	      }
-	    loongarch_xfer_reg (regcache, a0, regsize, nullptr, buf, 0);
+
+	    loongarch_xfer_reg (regcache, a0, regsize, nullptr, buf.data (),
+				0);
 	  }
 	else
 	  loongarch_xfer_reg (regcache, a0, len, readbuf, nullptr, 0);

gdb/mips-linux-tdep.c

@@ -99,16 +99,17 @@ mips_linux_get_longjmp_target (const frame_info_ptr &frame, CORE_ADDR *pc)
   CORE_ADDR jb_addr;
   struct gdbarch *gdbarch = get_frame_arch (frame);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  gdb_byte buf[gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT];
+  gdb::byte_vector buf (gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT);
 
   jb_addr = get_frame_register_unsigned (frame, MIPS_A0_REGNUM);
 
   if (target_read_memory ((jb_addr
 			   + MIPS_LINUX_JB_PC * MIPS_LINUX_JB_ELEMENT_SIZE),
-			  buf, gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT))
+			  buf.data (),
+			  gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT))
     return 0;
 
-  *pc = extract_unsigned_integer (buf,
+  *pc = extract_unsigned_integer (buf.data (),
 				  gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT,
 				  byte_order);
 

gdb/nat/aarch64-mte-linux-ptrace.c

@@ -119,10 +119,10 @@ aarch64_mte_fetch_memtags (int tid, CORE_ADDR address, size_t len,
   if (ntags == 0)
     return true;
 
-  gdb_byte tagbuf[ntags];
+  gdb::byte_vector tagbuf (ntags);
 
   struct iovec iovec;
-  iovec.iov_base = tagbuf;
+  iovec.iov_base = tagbuf.data ();
   iovec.iov_len = ntags;
 
   tags.clear ();

gdb/nat/aarch64-scalable-linux-ptrace.c

@@ -920,8 +920,7 @@ aarch64_za_regs_copy_to_reg_buf (int tid, struct reg_buffer_common *reg_buf,
   else
     {
       size_t za_bytes = header->vl * header->vl;
-      gdb_byte za_zeroed[za_bytes];
+      gdb::byte_vector za_zeroed (za_bytes, 0);
-      memset (za_zeroed, 0, za_bytes);
       reg_buf->raw_supply (za_regnum, za_zeroed);
     }
 
@@ -994,8 +993,7 @@ aarch64_za_regs_copy_from_reg_buf (int tid,
   bool has_za_state = aarch64_has_za_state (tid);
 
   size_t za_bytes = sve_vl_from_vg (old_svg) * sve_vl_from_vg (old_svg);
-  gdb_byte za_zeroed[za_bytes];
+  gdb::byte_vector za_zeroed (za_bytes, 0);
-  memset (za_zeroed, 0, za_bytes);
 
   /* If the streaming vector length changed, zero out the contents of ZA in
      the register cache.  Otherwise, we will need to update the ZA contents
@@ -1007,8 +1005,7 @@ aarch64_za_regs_copy_from_reg_buf (int tid,
   /* When we update svg, we don't automatically initialize the ZA buffer.  If
      we have no ZA state and the ZA register contents in the register cache are
      zero, just return and leave the ZA register cache contents as zero.  */
-  if (!has_za_state
+  if (!has_za_state && reg_buf->raw_compare (za_regnum, za_zeroed.data (), 0))
-      && reg_buf->raw_compare (za_regnum, za_zeroed, 0))
     {
       /* No ZA state in the thread or in the register cache.  This was likely
 	 just an adjustment of the streaming vector length.  Let this fall
@@ -1020,7 +1017,7 @@ aarch64_za_regs_copy_from_reg_buf (int tid,
 	 need to initialize the ZA data through ptrace.  First we initialize
 	 all the bytes of ZA to zero.  */
       if (!has_za_state
-	  && !reg_buf->raw_compare (za_regnum, za_zeroed, 0))
+	  && !reg_buf->raw_compare (za_regnum, za_zeroed.data (), 0))
 	aarch64_initialize_za_regset (tid);
 
       /* From this point onwards, it is assumed we have a ZA payload in

gdb/riscv-tdep.c

@@ -1015,7 +1015,7 @@ riscv_pseudo_register_write (struct gdbarch *gdbarch,
   if (regnum == tdep->fflags_regnum || regnum == tdep->frm_regnum)
     {
       int fcsr_regnum = RISCV_CSR_FCSR_REGNUM;
-      gdb_byte raw_buf[register_size (gdbarch, fcsr_regnum)];
+      gdb::byte_vector raw_buf (register_size (gdbarch, fcsr_regnum));
 
       regcache->raw_read (fcsr_regnum, raw_buf);
 

gdb/solib-darwin.c

@@ -239,18 +239,18 @@ darwin_current_sos ()
   for (int i = 0; i < info->all_image.count; i++)
     {
       CORE_ADDR iinfo = info->all_image.info + i * image_info_size;
-      gdb_byte buf[image_info_size];
+      gdb::byte_vector buf (image_info_size);
       CORE_ADDR load_addr;
       CORE_ADDR path_addr;
       struct mach_o_header_external hdr;
       unsigned long hdr_val;
 
       /* Read image info from inferior.  */
-      if (target_read_memory (iinfo, buf, image_info_size))
+      if (target_read_memory (iinfo, buf.data (), image_info_size))
 	break;
 
-      load_addr = extract_typed_address (buf, ptr_type);
+      load_addr = extract_typed_address (buf.data (), ptr_type);
-      path_addr = extract_typed_address (buf + ptr_len, ptr_type);
+      path_addr = extract_typed_address (buf.data () + ptr_len, ptr_type);
 
       /* Read Mach-O header from memory.  */
       if (target_read_memory (load_addr, (gdb_byte *) &hdr, sizeof (hdr) - 4))
@@ -333,14 +333,14 @@ darwin_read_exec_load_addr_from_dyld (struct darwin_info *info)
   for (i = 0; i < info->all_image.count; i++)
     {
       CORE_ADDR iinfo = info->all_image.info + i * image_info_size;
-      gdb_byte buf[image_info_size];
+      gdb::byte_vector buf (image_info_size);
       CORE_ADDR load_addr;
 
       /* Read image info from inferior.  */
-      if (target_read_memory (iinfo, buf, image_info_size))
+      if (target_read_memory (iinfo, buf.data (), image_info_size))
 	break;
 
-      load_addr = extract_typed_address (buf, ptr_type);
+      load_addr = extract_typed_address (buf.data (), ptr_type);
       if (darwin_validate_exec_header (load_addr) == load_addr)
 	return load_addr;
     }

gdb/trad-frame.c

@@ -154,12 +154,14 @@ trad_frame_set_reg_regmap (struct trad_frame_cache *this_trad_cache,
 	    else
 	      {
 		enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-		gdb_byte buf[slot_size];
+		gdb::byte_vector buf (slot_size);
 
-		if (target_read_memory (addr + offs, buf, sizeof buf) == 0)
+		if (target_read_memory (addr + offs, buf.data (), buf.size ())
+		    == 0)
 		  {
 		    LONGEST val
-		      = extract_unsigned_integer (buf, sizeof buf, byte_order);
+		      = extract_unsigned_integer (buf.data (), buf.size (),
+						  byte_order);
 		    trad_frame_set_reg_value (this_trad_cache, regno, val);
 		  }
 	      }