gdb/cp-valprint.c - binutils-gdb - Git at Google

 /* Support for printing C++ values for GDB, the GNU debugger.

    Copyright (C) 1986-2023 Free Software Foundation, Inc.

    This file is part of GDB.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

 #include "defs.h"
 #include "gdbsupport/gdb_obstack.h"
 #include "symtab.h"
 #include "gdbtypes.h"
 #include "expression.h"
 #include "value.h"
 #include "command.h"
 #include "gdbcmd.h"
 #include "demangle.h"
 #include "annotate.h"
 #include "c-lang.h"
 #include "target.h"
 #include "cp-abi.h"
 #include "valprint.h"
 #include "cp-support.h"
 #include "language.h"
 #include "extension.h"
 #include "typeprint.h"
 #include "gdbsupport/byte-vector.h"
 #include "gdbarch.h"
 #include "cli/cli-style.h"
 #include "gdbsupport/selftest.h"
 #include "selftest-arch.h"

 static struct obstack dont_print_vb_obstack;
 static struct obstack dont_print_statmem_obstack;
 static struct obstack dont_print_stat_array_obstack;

 static void cp_print_static_field (struct type *, struct value *,
 				   struct ui_file *, int,
 				   const struct value_print_options *);

 static void cp_print_value (struct value *, struct ui_file *,
 			    int, const struct value_print_options *,
 			    struct type **);


 /* GCC versions after 2.4.5 use this.  */
 const char vtbl_ptr_name[] = "__vtbl_ptr_type";

 /* Return truth value for assertion that TYPE is of the type
    "pointer to virtual function".  */

 int
 cp_is_vtbl_ptr_type (struct type *type)
 {
   const char *type_name = type->name ();

   return (type_name != NULL && !strcmp (type_name, vtbl_ptr_name));
 }

 /* Return truth value for the assertion that TYPE is of the type
    "pointer to virtual function table".  */

 int
 cp_is_vtbl_member (struct type *type)
 {
   /* With older versions of g++, the vtbl field pointed to an array of
      structures.  Nowadays it points directly to the structure.  */
   if (type->code () == TYPE_CODE_PTR)
     {
       type = type->target_type ();
       if (type->code () == TYPE_CODE_ARRAY)
 	{
 	  type = type->target_type ();
 	  if (type->code () == TYPE_CODE_STRUCT    /* if not using thunks */
 	      || type->code () == TYPE_CODE_PTR)   /* if using thunks */
 	    {
 	      /* Virtual functions tables are full of pointers
 		 to virtual functions.  */
 	      return cp_is_vtbl_ptr_type (type);
 	    }
 	}
       else if (type->code () == TYPE_CODE_STRUCT)  /* if not using thunks */
 	{
 	  return cp_is_vtbl_ptr_type (type);
 	}
       else if (type->code () == TYPE_CODE_PTR)     /* if using thunks */
 	{
 	  /* The type name of the thunk pointer is NULL when using
 	     dwarf2.  We could test for a pointer to a function, but
 	     there is no type info for the virtual table either, so it
 	     wont help.  */
 	  return cp_is_vtbl_ptr_type (type);
 	}
     }
   return 0;
 }

 /* Mutually recursive subroutines of cp_print_value and c_val_print to
    print out a structure's fields: cp_print_value_fields and
    cp_print_value.

    TYPE, VALADDR, ADDRESS, STREAM, RECURSE, and OPTIONS have the same
    meanings as in cp_print_value and c_val_print.

    2nd argument REAL_TYPE is used to carry over the type of the
    derived class across the recursion to base classes.

    DONT_PRINT is an array of baseclass types that we should not print,
    or zero if called from top level.  */

 void
 cp_print_value_fields (struct value *val, struct ui_file *stream,
 		       int recurse, const struct value_print_options *options,
 		       struct type **dont_print_vb,
 		       int dont_print_statmem)
 {
   int i, len, n_baseclasses;
   int fields_seen = 0;
   static int last_set_recurse = -1;

   struct type *type = check_typedef (val->type ());

   if (recurse == 0)
     {
       /* Any object can be left on obstacks only during an unexpected
 	 error.  */

       if (obstack_object_size (&dont_print_statmem_obstack) > 0)
 	{
 	  obstack_free (&dont_print_statmem_obstack, NULL);
 	  obstack_begin (&dont_print_statmem_obstack,
 			 32 * sizeof (CORE_ADDR));
 	}
       if (obstack_object_size (&dont_print_stat_array_obstack) > 0)
 	{
 	  obstack_free (&dont_print_stat_array_obstack, NULL);
 	  obstack_begin (&dont_print_stat_array_obstack,
 			 32 * sizeof (struct type *));
 	}
     }

   gdb_printf (stream, "{");
   len = type->num_fields ();
   n_baseclasses = TYPE_N_BASECLASSES (type);

   /* First, print out baseclasses such that we don't print
      duplicates of virtual baseclasses.  */

   if (n_baseclasses > 0)
     cp_print_value (val, stream, recurse + 1, options, dont_print_vb);

   /* Second, print out data fields */

   /* If there are no data fields, skip this part */
   if (len == n_baseclasses || !len)
     fprintf_styled (stream, metadata_style.style (), "<No data fields>");
   else
     {
       size_t statmem_obstack_initial_size = 0;
       size_t stat_array_obstack_initial_size = 0;
       struct type *vptr_basetype = NULL;
       int vptr_fieldno;

       if (dont_print_statmem == 0)
 	{
 	  statmem_obstack_initial_size =
 	    obstack_object_size (&dont_print_statmem_obstack);

 	  if (last_set_recurse != recurse)
 	    {
 	      stat_array_obstack_initial_size =
 		obstack_object_size (&dont_print_stat_array_obstack);

 	      last_set_recurse = recurse;
 	    }
 	}

       vptr_fieldno = get_vptr_fieldno (type, &vptr_basetype);
       for (i = n_baseclasses; i < len; i++)
 	{
 	  const gdb_byte *valaddr = val->contents_for_printing ().data ();

 	  /* If requested, skip printing of static fields.  */
 	  if (!options->static_field_print
 	      && field_is_static (&type->field (i)))
 	    continue;

 	  if (fields_seen)
 	    {
 	      gdb_puts (",", stream);
 	      if (!options->prettyformat)
 		gdb_puts (" ", stream);
 	    }
 	  else if (n_baseclasses > 0)
 	    {
 	      if (options->prettyformat)
 		{
 		  gdb_printf (stream, "\n");
 		  print_spaces (2 + 2 * recurse, stream);
 		  gdb_puts ("members of ", stream);
 		  gdb_puts (type->name (), stream);
 		  gdb_puts (":", stream);
 		}
 	    }
 	  fields_seen = 1;

 	  if (options->prettyformat)
 	    {
 	      gdb_printf (stream, "\n");
 	      print_spaces (2 + 2 * recurse, stream);
 	    }
 	  else
 	    {
 	      stream->wrap_here (2 + 2 * recurse);
 	    }

 	  annotate_field_begin (type->field (i).type ());

 	  if (field_is_static (&type->field (i)))
 	    {
 	      gdb_puts ("static ", stream);
 	      fprintf_symbol (stream,
 			      type->field (i).name (),
 			      current_language->la_language,
 			      DMGL_PARAMS | DMGL_ANSI);
 	    }
 	  else
 	    fputs_styled (type->field (i).name (),
 			  variable_name_style.style (), stream);
 	  annotate_field_name_end ();

 	  /* We tweak various options in a few cases below.  */
 	  value_print_options options_copy = *options;
 	  value_print_options *opts = &options_copy;

 	  /* Do not print leading '=' in case of anonymous
 	     unions.  */
 	  if (strcmp (type->field (i).name (), ""))
 	    gdb_puts (" = ", stream);
 	  else
 	    {
 	      /* If this is an anonymous field then we want to consider it
 		 as though it is at its parent's depth when it comes to the
 		 max print depth.  */
 	      if (opts->max_depth != -1 && opts->max_depth < INT_MAX)
 		++opts->max_depth;
 	    }
 	  annotate_field_value ();

 	  if (!field_is_static (&type->field (i))
 	      && TYPE_FIELD_PACKED (type, i))
 	    {
 	      struct value *v;

 	      /* Bitfields require special handling, especially due to
 		 byte order problems.  */
 	      if (TYPE_FIELD_IGNORE (type, i))
 		{
 		  fputs_styled ("<optimized out or zero length>",
 				metadata_style.style (), stream);
 		}
 	      else if (val->bits_synthetic_pointer
 		       (type->field (i).loc_bitpos (),
 			TYPE_FIELD_BITSIZE (type, i)))
 		{
 		  fputs_styled (_("<synthetic pointer>"),
 				metadata_style.style (), stream);
 		}
 	      else
 		{
 		  opts->deref_ref = false;

 		  v = value_field_bitfield (type, i, valaddr,
 					    val->embedded_offset (), val);

 		  common_val_print (v, stream, recurse + 1,
 				    opts, current_language);
 		}
 	    }
 	  else
 	    {
 	      if (TYPE_FIELD_IGNORE (type, i))
 		{
 		  fputs_styled ("<optimized out or zero length>",
 				metadata_style.style (), stream);
 		}
 	      else if (field_is_static (&type->field (i)))
 		{
 		  try
 		    {
 		      struct value *v = value_static_field (type, i);

 		      cp_print_static_field (type->field (i).type (),
 					     v, stream, recurse + 1,
 					     opts);
 		    }
 		  catch (const gdb_exception_error &ex)
 		    {
 		      fprintf_styled (stream, metadata_style.style (),
 				      _("<error reading variable: %s>"),
 				      ex.what ());
 		    }
 		}
 	      else if (i == vptr_fieldno && type == vptr_basetype)
 		{
 		  int i_offset = type->field (i).loc_bitpos () / 8;
 		  struct type *i_type = type->field (i).type ();

 		  if (valprint_check_validity (stream, i_type, i_offset, val))
 		    {
 		      CORE_ADDR addr;

 		      i_offset += val->embedded_offset ();
 		      addr = extract_typed_address (valaddr + i_offset, i_type);
 		      print_function_pointer_address (opts,
 						      type->arch (),
 						      addr, stream);
 		    }
 		}
 	      else
 		{
 		  struct value *v = val->primitive_field (0, i, type);
 		  opts->deref_ref = false;
 		  common_val_print (v, stream, recurse + 1, opts,
 				    current_language);
 		}
 	    }
 	  annotate_field_end ();
 	}

       if (dont_print_statmem == 0)
 	{
 	  size_t obstack_final_size =
 	   obstack_object_size (&dont_print_statmem_obstack);

 	  if (obstack_final_size > statmem_obstack_initial_size)
 	    {
 	      /* In effect, a pop of the printed-statics stack.  */
 	      size_t shrink_bytes
 		= statmem_obstack_initial_size - obstack_final_size;
 	      obstack_blank_fast (&dont_print_statmem_obstack, shrink_bytes);
 	    }

 	  if (last_set_recurse != recurse)
 	    {
 	      obstack_final_size =
 		obstack_object_size (&dont_print_stat_array_obstack);

 	      if (obstack_final_size > stat_array_obstack_initial_size)
 		{
 		  void *free_to_ptr =
 		    (char *) obstack_next_free (&dont_print_stat_array_obstack)
 		    - (obstack_final_size
 		       - stat_array_obstack_initial_size);

 		  obstack_free (&dont_print_stat_array_obstack,
 				free_to_ptr);
 		}
 	      last_set_recurse = -1;
 	    }
 	}

       if (options->prettyformat)
 	{
 	  gdb_printf (stream, "\n");
 	  print_spaces (2 * recurse, stream);
 	}
     }				/* if there are data fields */

   gdb_printf (stream, "}");
 }

 /* Special val_print routine to avoid printing multiple copies of
    virtual baseclasses.  */

 static void
 cp_print_value (struct value *val, struct ui_file *stream,
 		int recurse, const struct value_print_options *options,
 		struct type **dont_print_vb)
 {
   struct type *type = check_typedef (val->type ());
   CORE_ADDR address = val->address ();
   struct type **last_dont_print
     = (struct type **) obstack_next_free (&dont_print_vb_obstack);
   struct obstack tmp_obstack = dont_print_vb_obstack;
   int i, n_baseclasses = TYPE_N_BASECLASSES (type);
   const gdb_byte *valaddr = val->contents_for_printing ().data ();

   if (dont_print_vb == 0)
     {
       /* If we're at top level, carve out a completely fresh chunk of
 	 the obstack and use that until this particular invocation
 	 returns.  */
       /* Bump up the high-water mark.  Now alpha is omega.  */
       obstack_finish (&dont_print_vb_obstack);
     }

   for (i = 0; i < n_baseclasses; i++)
     {
       LONGEST boffset = 0;
       int skip = 0;
       struct type *baseclass = check_typedef (TYPE_BASECLASS (type, i));
       const char *basename = baseclass->name ();
       struct value *base_val = NULL;

       if (BASETYPE_VIA_VIRTUAL (type, i))
 	{
 	  struct type **first_dont_print
 	    = (struct type **) obstack_base (&dont_print_vb_obstack);

 	  int j = (struct type **)
 	    obstack_next_free (&dont_print_vb_obstack) - first_dont_print;

 	  while (--j >= 0)
 	    if (baseclass == first_dont_print[j])
 	      goto flush_it;

 	  obstack_ptr_grow (&dont_print_vb_obstack, baseclass);
 	}

       try
 	{
 	  boffset = baseclass_offset (type, i, valaddr,
 				      val->embedded_offset (),
 				      address, val);
 	}
       catch (const gdb_exception_error &ex)
 	{
 	  if (ex.error == NOT_AVAILABLE_ERROR)
 	    skip = -1;
 	  else
 	    skip = 1;
 	}

       if (skip == 0)
 	{
 	  if (BASETYPE_VIA_VIRTUAL (type, i))
 	    {
 	      /* The virtual base class pointer might have been
 		 clobbered by the user program. Make sure that it
 		 still points to a valid memory location.  */

 	      if (boffset < 0 || boffset >= type->length ())
 		{
 		  gdb::byte_vector buf (baseclass->length ());

 		  if (target_read_memory (address + boffset, buf.data (),
 					  baseclass->length ()) != 0)
 		    skip = 1;
 		  base_val = value_from_contents_and_address (baseclass,
 							      buf.data (),
 							      address + boffset);
 		  baseclass = base_val->type ();
 		  boffset = 0;
 		}
 	      else
 		{
 		  base_val = val;
 		}
 	    }
 	  else
 	    {
 	      base_val = val;
 	    }
 	}

       /* Now do the printing.  */
       if (options->prettyformat)
 	{
 	  gdb_printf (stream, "\n");
 	  print_spaces (2 * recurse, stream);
 	}
       gdb_puts ("<", stream);
       /* Not sure what the best notation is in the case where there is
 	 no baseclass name.  */
       gdb_puts (basename ? basename : "", stream);
       gdb_puts ("> = ", stream);

       if (skip < 0)
 	val_print_unavailable (stream);
       else if (skip > 0)
 	val_print_invalid_address (stream);
       else
 	{
 	  int result = 0;

 	  if (!val_print_check_max_depth (stream, recurse, options,
 					  current_language))
 	    {
 	      struct value *baseclass_val = val->primitive_field (0,
 								  i, type);

 	      /* Attempt to run an extension language pretty-printer on the
 		 baseclass if possible.  */
 	      if (!options->raw)
 		result
 		  = apply_ext_lang_val_pretty_printer (baseclass_val, stream,
 						       recurse, options,
 						       current_language);

 	      if (!result)
 		cp_print_value_fields (baseclass_val, stream, recurse, options,
 				       ((struct type **)
 					obstack_base (&dont_print_vb_obstack)),
 				       0);
 	    }
 	}
       gdb_puts (", ", stream);

     flush_it:
       ;
     }

   if (dont_print_vb == 0)
     {
       /* Free the space used to deal with the printing
 	 of this type from top level.  */
       obstack_free (&dont_print_vb_obstack, last_dont_print);
       /* Reset watermark so that we can continue protecting
 	 ourselves from whatever we were protecting ourselves.  */
       dont_print_vb_obstack = tmp_obstack;
     }
 }

 /* Print value of a static member.  To avoid infinite recursion when
    printing a class that contains a static instance of the class, we
    keep the addresses of all printed static member classes in an
    obstack and refuse to print them more than once.

    VAL contains the value to print, TYPE, STREAM, RECURSE, and OPTIONS
    have the same meanings as in c_val_print.  */

 static void
 cp_print_static_field (struct type *type,
 		       struct value *val,
 		       struct ui_file *stream,
 		       int recurse,
 		       const struct value_print_options *options)
 {
   struct value_print_options opts;

   if (val->entirely_optimized_out ())
     {
       val_print_optimized_out (val, stream);
       return;
     }

   struct type *real_type = check_typedef (type);
   if (real_type->code () == TYPE_CODE_STRUCT)
     {
       CORE_ADDR *first_dont_print;
       CORE_ADDR addr = val->address ();
       int i;

       first_dont_print
 	= (CORE_ADDR *) obstack_base (&dont_print_statmem_obstack);
       i = obstack_object_size (&dont_print_statmem_obstack)
 	/ sizeof (CORE_ADDR);

       while (--i >= 0)
 	{
 	  if (addr == first_dont_print[i])
 	    {
 	      fputs_styled (_("<same as static member of an already"
 			      " seen type>"),
 			    metadata_style.style (), stream);
 	      return;
 	    }
 	}

       obstack_grow (&dont_print_statmem_obstack, (char *) &addr,
 		    sizeof (CORE_ADDR));
       cp_print_value_fields (val, stream, recurse, options, NULL, 1);
       return;
     }

   if (real_type->code () == TYPE_CODE_ARRAY)
     {
       struct type **first_dont_print;
       int i;
       struct type *target_type = type->target_type ();

       first_dont_print
 	= (struct type **) obstack_base (&dont_print_stat_array_obstack);
       i = obstack_object_size (&dont_print_stat_array_obstack)
 	/ sizeof (struct type *);

       while (--i >= 0)
 	{
 	  if (target_type == first_dont_print[i])
 	    {
 	      fputs_styled (_("<same as static member of an already"
 			      " seen type>"),
 			    metadata_style.style (), stream);
 	      return;
 	    }
 	}

       obstack_grow (&dont_print_stat_array_obstack,
 		    (char *) &target_type,
 		    sizeof (struct type *));
     }

   opts = *options;
   opts.deref_ref = false;
   common_val_print (val, stream, recurse, &opts, current_language);
 }

 /* Find the field in *SELF, or its non-virtual base classes, with
    bit offset OFFSET.  Set *SELF to the containing type and *FIELDNO
    to the containing field number.  If OFFSET is not exactly at the
    start of some field, set *SELF to NULL.  */

 static void
 cp_find_class_member (struct type **self_p, int *fieldno,
 		      LONGEST offset)
 {
   struct type *self;
   unsigned int i;
   unsigned len;

   *self_p = check_typedef (*self_p);
   self = *self_p;
   len = self->num_fields ();

   for (i = TYPE_N_BASECLASSES (self); i < len; i++)
     {
       field &f = self->field (i);
       if (field_is_static (&f))
 	continue;
       LONGEST bitpos = f.loc_bitpos ();

       QUIT;
       if (offset == bitpos)
 	{
 	  *fieldno = i;
 	  return;
 	}
     }

   for (i = 0; i < TYPE_N_BASECLASSES (self); i++)
     {
       LONGEST bitpos = self->field (i).loc_bitpos ();
       LONGEST bitsize = 8 * self->field (i).type ()->length ();

       if (offset >= bitpos && offset < bitpos + bitsize)
 	{
 	  *self_p = self->field (i).type ();
 	  cp_find_class_member (self_p, fieldno, offset - bitpos);
 	  return;
 	}
     }

   *self_p = NULL;
 }

 void
 cp_print_class_member (const gdb_byte *valaddr, struct type *type,
 		       struct ui_file *stream, const char *prefix)
 {
   enum bfd_endian byte_order = type_byte_order (type);

   /* VAL is a byte offset into the structure type SELF_TYPE.
      Find the name of the field for that offset and
      print it.  */
   struct type *self_type = TYPE_SELF_TYPE (type);
   LONGEST val;
   int fieldno;

   val = extract_signed_integer (valaddr,
 				type->length (),
 				byte_order);

   /* Pointers to data members are usually byte offsets into an object.
      Because a data member can have offset zero, and a NULL pointer to
      member must be distinct from any valid non-NULL pointer to
      member, either the value is biased or the NULL value has a
      special representation; both are permitted by ISO C++.  HP aCC
      used a bias of 0x20000000; HP cfront used a bias of 1; g++ 3.x
      and other compilers which use the Itanium ABI use -1 as the NULL
      value.  GDB only supports that last form; to add support for
      another form, make this into a cp-abi hook.  */

   if (val == -1)
     {
       gdb_printf (stream, "NULL");
       return;
     }

   cp_find_class_member (&self_type, &fieldno, val << 3);

   if (self_type != NULL)
     {
       const char *name;

       gdb_puts (prefix, stream);
       name = self_type->name ();
       if (name)
 	gdb_puts (name, stream);
       else
 	c_type_print_base (self_type, stream, 0, 0, &type_print_raw_options);
       gdb_printf (stream, "::");
       fputs_styled (self_type->field (fieldno).name (),
 		    variable_name_style.style (), stream);
     }
   else
     gdb_printf (stream, "%ld", (long) val);
 }

 #if GDB_SELF_TEST

 /* Test printing of TYPE_CODE_STRUCT values.  */

 static void
 test_print_fields (gdbarch *arch)
 {
   struct field *f;
   type *uint8_type = builtin_type (arch)->builtin_uint8;
   type *bool_type = builtin_type (arch)->builtin_bool;
   type *the_struct = arch_composite_type (arch, NULL, TYPE_CODE_STRUCT);
   the_struct->set_length (4);

   /* Value:  1110 1001
      Fields: C-BB B-A- */
   if (gdbarch_byte_order (arch) == BFD_ENDIAN_LITTLE)
     {
       f = append_composite_type_field_raw (the_struct, "A", bool_type);
       f->set_loc_bitpos (1);
       FIELD_BITSIZE (*f) = 1;
       f = append_composite_type_field_raw (the_struct, "B", uint8_type);
       f->set_loc_bitpos (3);
       FIELD_BITSIZE (*f) = 3;
       f = append_composite_type_field_raw (the_struct, "C", bool_type);
       f->set_loc_bitpos (7);
       FIELD_BITSIZE (*f) = 1;
     }
   /* According to the logic commented in "make_gdb_type_struct ()" of
    * target-descriptions.c, bit positions are numbered differently for
    * little and big endians.  */
   else
     {
       f = append_composite_type_field_raw (the_struct, "A", bool_type);
       f->set_loc_bitpos (30);
       FIELD_BITSIZE (*f) = 1;
       f = append_composite_type_field_raw (the_struct, "B", uint8_type);
       f->set_loc_bitpos (26);
       FIELD_BITSIZE (*f) = 3;
       f = append_composite_type_field_raw (the_struct, "C", bool_type);
       f->set_loc_bitpos (24);
       FIELD_BITSIZE (*f) = 1;
     }

   value *val = value::allocate (the_struct);
   gdb_byte *contents = val->contents_writeable ().data ();
   store_unsigned_integer (contents, val->enclosing_type ()->length (),
 			  gdbarch_byte_order (arch), 0xe9);

   string_file out;
   struct value_print_options opts;
   get_no_prettyformat_print_options (&opts);
   cp_print_value_fields(val, &out, 0, &opts, NULL, 0);
   SELF_CHECK (out.string () == "{A = false, B = 5, C = true}");

   out.clear();
   opts.format = 'x';
   cp_print_value_fields(val, &out, 0, &opts, NULL, 0);
   SELF_CHECK (out.string () == "{A = 0x0, B = 0x5, C = 0x1}");
 }

 #endif


 void _initialize_cp_valprint ();
 void
 _initialize_cp_valprint ()
 {
 #if GDB_SELF_TEST
   selftests::register_test_foreach_arch ("print-fields", test_print_fields);
 #endif

   obstack_begin (&dont_print_stat_array_obstack,
 		 32 * sizeof (struct type *));
   obstack_begin (&dont_print_statmem_obstack,
 		 32 * sizeof (CORE_ADDR));
   obstack_begin (&dont_print_vb_obstack,
 		 32 * sizeof (struct type *));
 }
	/* Support for printing C++ values for GDB, the GNU debugger.

	Copyright (C) 1986-2023 Free Software Foundation, Inc.

	This file is part of GDB.

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program. If not, see <http://www.gnu.org/licenses/>. */

	#include "defs.h"
	#include "gdbsupport/gdb_obstack.h"
	#include "symtab.h"
	#include "gdbtypes.h"
	#include "expression.h"
	#include "value.h"
	#include "command.h"
	#include "gdbcmd.h"
	#include "demangle.h"
	#include "annotate.h"
	#include "c-lang.h"
	#include "target.h"
	#include "cp-abi.h"
	#include "valprint.h"
	#include "cp-support.h"
	#include "language.h"
	#include "extension.h"
	#include "typeprint.h"
	#include "gdbsupport/byte-vector.h"
	#include "gdbarch.h"
	#include "cli/cli-style.h"
	#include "gdbsupport/selftest.h"
	#include "selftest-arch.h"

	static struct obstack dont_print_vb_obstack;
	static struct obstack dont_print_statmem_obstack;
	static struct obstack dont_print_stat_array_obstack;

	static void cp_print_static_field (struct type , struct value ,
	struct ui_file *, int,
	const struct value_print_options *);

	static void cp_print_value (struct value , struct ui_file ,
	int, const struct value_print_options *,
	struct type **);


	/* GCC versions after 2.4.5 use this. */
	const char vtbl_ptr_name[] = "__vtbl_ptr_type";

	/* Return truth value for assertion that TYPE is of the type
	"pointer to virtual function". */

	int
	cp_is_vtbl_ptr_type (struct type *type)
	{
	const char *type_name = type->name ();

	return (type_name != NULL && !strcmp (type_name, vtbl_ptr_name));
	}

	/* Return truth value for the assertion that TYPE is of the type
	"pointer to virtual function table". */

	int
	cp_is_vtbl_member (struct type *type)
	{
	/* With older versions of g++, the vtbl field pointed to an array of
	structures. Nowadays it points directly to the structure. */
	if (type->code () == TYPE_CODE_PTR)
	{
	type = type->target_type ();
	if (type->code () == TYPE_CODE_ARRAY)
	{
	type = type->target_type ();
	if (type->code () == TYPE_CODE_STRUCT /* if not using thunks */
	\|\| type->code () == TYPE_CODE_PTR) /* if using thunks */
	{
	/* Virtual functions tables are full of pointers
	to virtual functions. */
	return cp_is_vtbl_ptr_type (type);
	}
	}
	else if (type->code () == TYPE_CODE_STRUCT) /* if not using thunks */
	{
	return cp_is_vtbl_ptr_type (type);
	}
	else if (type->code () == TYPE_CODE_PTR) /* if using thunks */
	{
	/* The type name of the thunk pointer is NULL when using
	dwarf2. We could test for a pointer to a function, but
	there is no type info for the virtual table either, so it
	wont help. */
	return cp_is_vtbl_ptr_type (type);
	}
	}
	return 0;
	}

	/* Mutually recursive subroutines of cp_print_value and c_val_print to
	print out a structure's fields: cp_print_value_fields and
	cp_print_value.

	TYPE, VALADDR, ADDRESS, STREAM, RECURSE, and OPTIONS have the same
	meanings as in cp_print_value and c_val_print.

	2nd argument REAL_TYPE is used to carry over the type of the
	derived class across the recursion to base classes.

	DONT_PRINT is an array of baseclass types that we should not print,
	or zero if called from top level. */

	void
	cp_print_value_fields (struct value val, struct ui_file stream,
	int recurse, const struct value_print_options *options,
	struct type **dont_print_vb,
	int dont_print_statmem)
	{
	int i, len, n_baseclasses;
	int fields_seen = 0;
	static int last_set_recurse = -1;

	struct type *type = check_typedef (val->type ());

	if (recurse == 0)
	{
	/* Any object can be left on obstacks only during an unexpected
	error. */

	if (obstack_object_size (&dont_print_statmem_obstack) > 0)
	{
	obstack_free (&dont_print_statmem_obstack, NULL);
	obstack_begin (&dont_print_statmem_obstack,
	32 * sizeof (CORE_ADDR));
	}
	if (obstack_object_size (&dont_print_stat_array_obstack) > 0)
	{
	obstack_free (&dont_print_stat_array_obstack, NULL);
	obstack_begin (&dont_print_stat_array_obstack,
	32 * sizeof (struct type *));
	}
	}

	gdb_printf (stream, "{");
	len = type->num_fields ();
	n_baseclasses = TYPE_N_BASECLASSES (type);

	/* First, print out baseclasses such that we don't print
	duplicates of virtual baseclasses. */

	if (n_baseclasses > 0)
	cp_print_value (val, stream, recurse + 1, options, dont_print_vb);

	/* Second, print out data fields */

	/* If there are no data fields, skip this part */
	if (len == n_baseclasses \|\| !len)
	fprintf_styled (stream, metadata_style.style (), "<No data fields>");
	else
	{
	size_t statmem_obstack_initial_size = 0;
	size_t stat_array_obstack_initial_size = 0;
	struct type *vptr_basetype = NULL;
	int vptr_fieldno;

	if (dont_print_statmem == 0)
	{
	statmem_obstack_initial_size =
	obstack_object_size (&dont_print_statmem_obstack);

	if (last_set_recurse != recurse)
	{
	stat_array_obstack_initial_size =
	obstack_object_size (&dont_print_stat_array_obstack);

	last_set_recurse = recurse;
	}
	}

	vptr_fieldno = get_vptr_fieldno (type, &vptr_basetype);
	for (i = n_baseclasses; i < len; i++)
	{
	const gdb_byte *valaddr = val->contents_for_printing ().data ();

	/* If requested, skip printing of static fields. */
	if (!options->static_field_print
	&& field_is_static (&type->field (i)))
	continue;

	if (fields_seen)
	{
	gdb_puts (",", stream);
	if (!options->prettyformat)
	gdb_puts (" ", stream);
	}
	else if (n_baseclasses > 0)
	{
	if (options->prettyformat)
	{
	gdb_printf (stream, "\n");
	print_spaces (2 + 2 * recurse, stream);
	gdb_puts ("members of ", stream);
	gdb_puts (type->name (), stream);
	gdb_puts (":", stream);
	}
	}
	fields_seen = 1;

	if (options->prettyformat)
	{
	gdb_printf (stream, "\n");
	print_spaces (2 + 2 * recurse, stream);
	}
	else
	{
	stream->wrap_here (2 + 2 * recurse);
	}

	annotate_field_begin (type->field (i).type ());

	if (field_is_static (&type->field (i)))
	{
	gdb_puts ("static ", stream);
	fprintf_symbol (stream,
	type->field (i).name (),
	current_language->la_language,
	DMGL_PARAMS \| DMGL_ANSI);
	}
	else
	fputs_styled (type->field (i).name (),
	variable_name_style.style (), stream);
	annotate_field_name_end ();

	/* We tweak various options in a few cases below. */
	value_print_options options_copy = *options;
	value_print_options *opts = &options_copy;

	/* Do not print leading '=' in case of anonymous
	unions. */
	if (strcmp (type->field (i).name (), ""))
	gdb_puts (" = ", stream);
	else
	{
	/* If this is an anonymous field then we want to consider it
	as though it is at its parent's depth when it comes to the
	max print depth. */
	if (opts->max_depth != -1 && opts->max_depth < INT_MAX)
	++opts->max_depth;
	}
	annotate_field_value ();

	if (!field_is_static (&type->field (i))
	&& TYPE_FIELD_PACKED (type, i))
	{
	struct value *v;

	/* Bitfields require special handling, especially due to
	byte order problems. */
	if (TYPE_FIELD_IGNORE (type, i))
	{
	fputs_styled ("<optimized out or zero length>",
	metadata_style.style (), stream);
	}
	else if (val->bits_synthetic_pointer
	(type->field (i).loc_bitpos (),
	TYPE_FIELD_BITSIZE (type, i)))
	{
	fputs_styled (_("<synthetic pointer>"),
	metadata_style.style (), stream);
	}
	else
	{
	opts->deref_ref = false;

	v = value_field_bitfield (type, i, valaddr,
	val->embedded_offset (), val);

	common_val_print (v, stream, recurse + 1,
	opts, current_language);
	}
	}
	else
	{
	if (TYPE_FIELD_IGNORE (type, i))
	{
	fputs_styled ("<optimized out or zero length>",
	metadata_style.style (), stream);
	}
	else if (field_is_static (&type->field (i)))
	{
	try
	{
	struct value *v = value_static_field (type, i);

	cp_print_static_field (type->field (i).type (),
	v, stream, recurse + 1,
	opts);
	}
	catch (const gdb_exception_error &ex)
	{
	fprintf_styled (stream, metadata_style.style (),
	_("<error reading variable: %s>"),
	ex.what ());
	}
	}
	else if (i == vptr_fieldno && type == vptr_basetype)
	{
	int i_offset = type->field (i).loc_bitpos () / 8;
	struct type *i_type = type->field (i).type ();

	if (valprint_check_validity (stream, i_type, i_offset, val))
	{
	CORE_ADDR addr;

	i_offset += val->embedded_offset ();
	addr = extract_typed_address (valaddr + i_offset, i_type);
	print_function_pointer_address (opts,
	type->arch (),
	addr, stream);
	}
	}
	else
	{
	struct value *v = val->primitive_field (0, i, type);
	opts->deref_ref = false;
	common_val_print (v, stream, recurse + 1, opts,
	current_language);
	}
	}
	annotate_field_end ();
	}

	if (dont_print_statmem == 0)
	{
	size_t obstack_final_size =
	obstack_object_size (&dont_print_statmem_obstack);

	if (obstack_final_size > statmem_obstack_initial_size)
	{
	/* In effect, a pop of the printed-statics stack. */
	size_t shrink_bytes
	= statmem_obstack_initial_size - obstack_final_size;
	obstack_blank_fast (&dont_print_statmem_obstack, shrink_bytes);
	}

	if (last_set_recurse != recurse)
	{
	obstack_final_size =
	obstack_object_size (&dont_print_stat_array_obstack);

	if (obstack_final_size > stat_array_obstack_initial_size)
	{
	void *free_to_ptr =
	(char *) obstack_next_free (&dont_print_stat_array_obstack)
	- (obstack_final_size
	- stat_array_obstack_initial_size);

	obstack_free (&dont_print_stat_array_obstack,
	free_to_ptr);
	}
	last_set_recurse = -1;
	}
	}

	if (options->prettyformat)
	{
	gdb_printf (stream, "\n");
	print_spaces (2 * recurse, stream);
	}
	} /* if there are data fields */

	gdb_printf (stream, "}");
	}

	/* Special val_print routine to avoid printing multiple copies of
	virtual baseclasses. */

	static void
	cp_print_value (struct value val, struct ui_file stream,
	int recurse, const struct value_print_options *options,
	struct type **dont_print_vb)
	{
	struct type *type = check_typedef (val->type ());
	CORE_ADDR address = val->address ();
	struct type **last_dont_print
	= (struct type **) obstack_next_free (&dont_print_vb_obstack);
	struct obstack tmp_obstack = dont_print_vb_obstack;
	int i, n_baseclasses = TYPE_N_BASECLASSES (type);
	const gdb_byte *valaddr = val->contents_for_printing ().data ();

	if (dont_print_vb == 0)
	{
	/* If we're at top level, carve out a completely fresh chunk of
	the obstack and use that until this particular invocation
	returns. */
	/* Bump up the high-water mark. Now alpha is omega. */
	obstack_finish (&dont_print_vb_obstack);
	}

	for (i = 0; i < n_baseclasses; i++)
	{
	LONGEST boffset = 0;
	int skip = 0;
	struct type *baseclass = check_typedef (TYPE_BASECLASS (type, i));
	const char *basename = baseclass->name ();
	struct value *base_val = NULL;

	if (BASETYPE_VIA_VIRTUAL (type, i))
	{
	struct type **first_dont_print
	= (struct type **) obstack_base (&dont_print_vb_obstack);

	int j = (struct type **)
	obstack_next_free (&dont_print_vb_obstack) - first_dont_print;

	while (--j >= 0)
	if (baseclass == first_dont_print[j])
	goto flush_it;

	obstack_ptr_grow (&dont_print_vb_obstack, baseclass);
	}

	try
	{
	boffset = baseclass_offset (type, i, valaddr,
	val->embedded_offset (),
	address, val);
	}
	catch (const gdb_exception_error &ex)
	{
	if (ex.error == NOT_AVAILABLE_ERROR)
	skip = -1;
	else
	skip = 1;
	}

	if (skip == 0)
	{
	if (BASETYPE_VIA_VIRTUAL (type, i))
	{
	/* The virtual base class pointer might have been
	clobbered by the user program. Make sure that it
	still points to a valid memory location. */

	if (boffset < 0 \|\| boffset >= type->length ())
	{
	gdb::byte_vector buf (baseclass->length ());

	if (target_read_memory (address + boffset, buf.data (),
	baseclass->length ()) != 0)
	skip = 1;
	base_val = value_from_contents_and_address (baseclass,
	buf.data (),
	address + boffset);
	baseclass = base_val->type ();
	boffset = 0;
	}
	else
	{
	base_val = val;
	}
	}
	else
	{
	base_val = val;
	}
	}

	/* Now do the printing. */
	if (options->prettyformat)
	{
	gdb_printf (stream, "\n");
	print_spaces (2 * recurse, stream);
	}
	gdb_puts ("<", stream);
	/* Not sure what the best notation is in the case where there is
	no baseclass name. */
	gdb_puts (basename ? basename : "", stream);
	gdb_puts ("> = ", stream);

	if (skip < 0)
	val_print_unavailable (stream);
	else if (skip > 0)
	val_print_invalid_address (stream);
	else
	{
	int result = 0;

	if (!val_print_check_max_depth (stream, recurse, options,
	current_language))
	{
	struct value *baseclass_val = val->primitive_field (0,
	i, type);

	/* Attempt to run an extension language pretty-printer on the
	baseclass if possible. */
	if (!options->raw)
	result
	= apply_ext_lang_val_pretty_printer (baseclass_val, stream,
	recurse, options,
	current_language);

	if (!result)
	cp_print_value_fields (baseclass_val, stream, recurse, options,
	((struct type **)
	obstack_base (&dont_print_vb_obstack)),
	0);
	}
	}
	gdb_puts (", ", stream);

	flush_it:
	;
	}

	if (dont_print_vb == 0)
	{
	/* Free the space used to deal with the printing
	of this type from top level. */
	obstack_free (&dont_print_vb_obstack, last_dont_print);
	/* Reset watermark so that we can continue protecting
	ourselves from whatever we were protecting ourselves. */
	dont_print_vb_obstack = tmp_obstack;
	}
	}

	/* Print value of a static member. To avoid infinite recursion when
	printing a class that contains a static instance of the class, we
	keep the addresses of all printed static member classes in an
	obstack and refuse to print them more than once.

	VAL contains the value to print, TYPE, STREAM, RECURSE, and OPTIONS
	have the same meanings as in c_val_print. */

	static void
	cp_print_static_field (struct type *type,
	struct value *val,
	struct ui_file *stream,
	int recurse,
	const struct value_print_options *options)
	{
	struct value_print_options opts;

	if (val->entirely_optimized_out ())
	{
	val_print_optimized_out (val, stream);
	return;
	}

	struct type *real_type = check_typedef (type);
	if (real_type->code () == TYPE_CODE_STRUCT)
	{
	CORE_ADDR *first_dont_print;
	CORE_ADDR addr = val->address ();
	int i;

	first_dont_print
	= (CORE_ADDR *) obstack_base (&dont_print_statmem_obstack);
	i = obstack_object_size (&dont_print_statmem_obstack)
	/ sizeof (CORE_ADDR);

	while (--i >= 0)
	{
	if (addr == first_dont_print[i])
	{
	fputs_styled (_("<same as static member of an already"
	" seen type>"),
	metadata_style.style (), stream);
	return;
	}
	}

	obstack_grow (&dont_print_statmem_obstack, (char *) &addr,
	sizeof (CORE_ADDR));
	cp_print_value_fields (val, stream, recurse, options, NULL, 1);
	return;
	}

	if (real_type->code () == TYPE_CODE_ARRAY)
	{
	struct type **first_dont_print;
	int i;
	struct type *target_type = type->target_type ();

	first_dont_print
	= (struct type **) obstack_base (&dont_print_stat_array_obstack);
	i = obstack_object_size (&dont_print_stat_array_obstack)
	/ sizeof (struct type *);

	while (--i >= 0)
	{
	if (target_type == first_dont_print[i])
	{
	fputs_styled (_("<same as static member of an already"
	" seen type>"),
	metadata_style.style (), stream);
	return;
	}
	}

	obstack_grow (&dont_print_stat_array_obstack,
	(char *) &target_type,
	sizeof (struct type *));
	}

	opts = *options;
	opts.deref_ref = false;
	common_val_print (val, stream, recurse, &opts, current_language);
	}

	/* Find the field in *SELF, or its non-virtual base classes, with
	bit offset OFFSET. Set SELF to the containing type and FIELDNO
	to the containing field number. If OFFSET is not exactly at the
	start of some field, set SELF to NULL. /

	static void
	cp_find_class_member (struct type *self_p, int fieldno,
	LONGEST offset)
	{
	struct type *self;
	unsigned int i;
	unsigned len;

	self_p = check_typedef (self_p);
	self = *self_p;
	len = self->num_fields ();

	for (i = TYPE_N_BASECLASSES (self); i < len; i++)
	{
	field &f = self->field (i);
	if (field_is_static (&f))
	continue;
	LONGEST bitpos = f.loc_bitpos ();

	QUIT;
	if (offset == bitpos)
	{
	*fieldno = i;
	return;
	}
	}

	for (i = 0; i < TYPE_N_BASECLASSES (self); i++)
	{
	LONGEST bitpos = self->field (i).loc_bitpos ();
	LONGEST bitsize = 8 * self->field (i).type ()->length ();

	if (offset >= bitpos && offset < bitpos + bitsize)
	{
	*self_p = self->field (i).type ();
	cp_find_class_member (self_p, fieldno, offset - bitpos);
	return;
	}
	}

	*self_p = NULL;
	}

	void
	cp_print_class_member (const gdb_byte valaddr, struct type type,
	struct ui_file stream, const char prefix)
	{
	enum bfd_endian byte_order = type_byte_order (type);

	/* VAL is a byte offset into the structure type SELF_TYPE.
	Find the name of the field for that offset and
	print it. */
	struct type *self_type = TYPE_SELF_TYPE (type);
	LONGEST val;
	int fieldno;

	val = extract_signed_integer (valaddr,
	type->length (),
	byte_order);

	/* Pointers to data members are usually byte offsets into an object.
	Because a data member can have offset zero, and a NULL pointer to
	member must be distinct from any valid non-NULL pointer to
	member, either the value is biased or the NULL value has a
	special representation; both are permitted by ISO C++. HP aCC
	used a bias of 0x20000000; HP cfront used a bias of 1; g++ 3.x
	and other compilers which use the Itanium ABI use -1 as the NULL
	value. GDB only supports that last form; to add support for
	another form, make this into a cp-abi hook. */

	if (val == -1)
	{
	gdb_printf (stream, "NULL");
	return;
	}

	cp_find_class_member (&self_type, &fieldno, val << 3);

	if (self_type != NULL)
	{
	const char *name;

	gdb_puts (prefix, stream);
	name = self_type->name ();
	if (name)
	gdb_puts (name, stream);
	else
	c_type_print_base (self_type, stream, 0, 0, &type_print_raw_options);
	gdb_printf (stream, "::");
	fputs_styled (self_type->field (fieldno).name (),
	variable_name_style.style (), stream);
	}
	else
	gdb_printf (stream, "%ld", (long) val);
	}

	#if GDB_SELF_TEST

	/* Test printing of TYPE_CODE_STRUCT values. */

	static void
	test_print_fields (gdbarch *arch)
	{
	struct field *f;
	type *uint8_type = builtin_type (arch)->builtin_uint8;
	type *bool_type = builtin_type (arch)->builtin_bool;
	type *the_struct = arch_composite_type (arch, NULL, TYPE_CODE_STRUCT);
	the_struct->set_length (4);

	/* Value: 1110 1001
	Fields: C-BB B-A- */
	if (gdbarch_byte_order (arch) == BFD_ENDIAN_LITTLE)
	{
	f = append_composite_type_field_raw (the_struct, "A", bool_type);
	f->set_loc_bitpos (1);
	FIELD_BITSIZE (*f) = 1;
	f = append_composite_type_field_raw (the_struct, "B", uint8_type);
	f->set_loc_bitpos (3);
	FIELD_BITSIZE (*f) = 3;
	f = append_composite_type_field_raw (the_struct, "C", bool_type);
	f->set_loc_bitpos (7);
	FIELD_BITSIZE (*f) = 1;
	}
	/* According to the logic commented in "make_gdb_type_struct ()" of
	* target-descriptions.c, bit positions are numbered differently for
	* little and big endians. */
	else
	{
	f = append_composite_type_field_raw (the_struct, "A", bool_type);
	f->set_loc_bitpos (30);
	FIELD_BITSIZE (*f) = 1;
	f = append_composite_type_field_raw (the_struct, "B", uint8_type);
	f->set_loc_bitpos (26);
	FIELD_BITSIZE (*f) = 3;
	f = append_composite_type_field_raw (the_struct, "C", bool_type);
	f->set_loc_bitpos (24);
	FIELD_BITSIZE (*f) = 1;
	}

	value *val = value::allocate (the_struct);
	gdb_byte *contents = val->contents_writeable ().data ();
	store_unsigned_integer (contents, val->enclosing_type ()->length (),
	gdbarch_byte_order (arch), 0xe9);

	string_file out;
	struct value_print_options opts;
	get_no_prettyformat_print_options (&opts);
	cp_print_value_fields(val, &out, 0, &opts, NULL, 0);
	SELF_CHECK (out.string () == "{A = false, B = 5, C = true}");

	out.clear();
	opts.format = 'x';
	cp_print_value_fields(val, &out, 0, &opts, NULL, 0);
	SELF_CHECK (out.string () == "{A = 0x0, B = 0x5, C = 0x1}");
	}

	#endif


	void _initialize_cp_valprint ();
	void
	_initialize_cp_valprint ()
	{
	#if GDB_SELF_TEST
	selftests::register_test_foreach_arch ("print-fields", test_print_fields);
	#endif

	obstack_begin (&dont_print_stat_array_obstack,
	32 * sizeof (struct type *));
	obstack_begin (&dont_print_statmem_obstack,
	32 * sizeof (CORE_ADDR));
	obstack_begin (&dont_print_vb_obstack,
	32 * sizeof (struct type *));
	}