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/* Build symbol tables in GDB's internal format.
   Copyright (C) 1986-2019 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/>.  */

#if !defined (BUILDSYM_H)
#define BUILDSYM_H 1

struct objfile;
struct symbol;
struct addrmap;
struct compunit_symtab;
enum language;

/* This module provides definitions used for creating and adding to
   the symbol table.  These routines are called from various symbol-
   file-reading routines.

   They originated in dbxread.c of gdb-4.2, and were split out to
   make xcoffread.c more maintainable by sharing code.  */

struct block;
struct pending_block;

struct dynamic_prop;

/* The list of sub-source-files within the current individual
   compilation.  Each file gets its own symtab with its own linetable
   and associated info, but they all share one blockvector.  */

struct subfile
{
  struct subfile *next;
  /* Space for this is malloc'd.  */
  char *name;
  /* Space for this is malloc'd.  */
  struct linetable *line_vector;
  int line_vector_length;
  /* The "containing" compunit.  */
  struct buildsym_compunit *buildsym_compunit;
  enum language language;
  struct symtab *symtab;
};

/* Record the symbols defined for each context in a list.  We don't
   create a struct block for the context until we know how long to
   make it.  */

#define PENDINGSIZE 100

struct pending
  {
    struct pending *next;
    int nsyms;
    struct symbol *symbol[PENDINGSIZE];
  };

/* Stack representing unclosed lexical contexts (that will become
   blocks, eventually).  */

struct context_stack
  {
    /* Outer locals at the time we entered */

    struct pending *locals;

    /* Pending using directives at the time we entered.  */

    struct using_direct *local_using_directives;

    /* Pointer into blocklist as of entry */

    struct pending_block *old_blocks;

    /* Name of function, if any, defining context */

    struct symbol *name;

    /* Expression that computes the frame base of the lexically enclosing
       function, if any.  NULL otherwise.  */

    struct dynamic_prop *static_link;

    /* PC where this context starts */

    CORE_ADDR start_addr;

    /* Temp slot for exception handling.  */

    CORE_ADDR end_addr;

    /* For error-checking matching push/pop */

    int depth;

  };

/* Buildsym's counterpart to struct compunit_symtab.  */

struct buildsym_compunit
{
  /* Start recording information about a primary source file (IOW, not an
     included source file).
     COMP_DIR is the directory in which the compilation unit was compiled
     (or NULL if not known).  */

  buildsym_compunit (struct objfile *objfile_, const char *name,
		     const char *comp_dir_, enum language language_,
		     CORE_ADDR last_addr);

  /* Reopen an existing compunit_symtab so that additional symbols can
     be added to it.  Arguments are as for the main constructor.  CUST
     is the expandable compunit_symtab to be reopened.  */

  buildsym_compunit (struct objfile *objfile_, const char *name,
		     const char *comp_dir_, enum language language_,
		     CORE_ADDR last_addr, struct compunit_symtab *cust)
    : m_objfile (objfile_),
      m_last_source_file (name == nullptr ? nullptr : xstrdup (name)),
      m_comp_dir (comp_dir_ == nullptr ? nullptr : xstrdup (comp_dir_)),
      m_compunit_symtab (cust),
      m_language (language_),
      m_last_source_start_addr (last_addr)
  {
  }

  ~buildsym_compunit ();

  DISABLE_COPY_AND_ASSIGN (buildsym_compunit);

  void set_last_source_file (const char *name)
  {
    char *new_name = name == NULL ? NULL : xstrdup (name);
    m_last_source_file.reset (new_name);
  }

  const char *get_last_source_file ()
  {
    return m_last_source_file.get ();
  }

  struct macro_table *get_macro_table ();

  struct macro_table *release_macros ()
  {
    struct macro_table *result = m_pending_macros;
    m_pending_macros = nullptr;
    return result;
  }

  /* This function is called to discard any pending blocks.  */

  void free_pending_blocks ()
  {
    m_pending_block_obstack.clear ();
    m_pending_blocks = nullptr;
  }

  struct block *finish_block (struct symbol *symbol,
			      struct pending_block *old_blocks,
			      const struct dynamic_prop *static_link,
			      CORE_ADDR start, CORE_ADDR end);

  void record_block_range (struct block *block,
			   CORE_ADDR start, CORE_ADDR end_inclusive);

  void start_subfile (const char *name);

  void patch_subfile_names (struct subfile *subfile, const char *name);

  void push_subfile ();

  const char *pop_subfile ();

  void record_line (struct subfile *subfile, int line, CORE_ADDR pc);

  struct compunit_symtab *get_compunit_symtab ()
  {
    return m_compunit_symtab;
  }

  void set_last_source_start_addr (CORE_ADDR addr)
  {
    m_last_source_start_addr = addr;
  }

  CORE_ADDR get_last_source_start_addr ()
  {
    return m_last_source_start_addr;
  }

  struct using_direct **get_local_using_directives ()
  {
    return &m_local_using_directives;
  }

  void set_local_using_directives (struct using_direct *new_local)
  {
    m_local_using_directives = new_local;
  }

  struct using_direct **get_global_using_directives ()
  {
    return &m_global_using_directives;
  }

  bool outermost_context_p () const
  {
    return m_context_stack.empty ();
  }

  struct context_stack *get_current_context_stack ()
  {
    if (m_context_stack.empty ())
      return nullptr;
    return &m_context_stack.back ();
  }

  int get_context_stack_depth () const
  {
    return m_context_stack.size ();
  }

  struct subfile *get_current_subfile ()
  {
    return m_current_subfile;
  }

  struct pending **get_local_symbols ()
  {
    return &m_local_symbols;
  }

  struct pending **get_file_symbols ()
  {
    return &m_file_symbols;
  }

  struct pending **get_global_symbols ()
  {
    return &m_global_symbols;
  }

  void record_debugformat (const char *format)
  {
    m_debugformat = format;
  }

  void record_producer (const char *producer)
  {
    m_producer = producer;
  }

  struct context_stack *push_context (int desc, CORE_ADDR valu);

  struct context_stack pop_context ();

  struct block *end_symtab_get_static_block (CORE_ADDR end_addr,
					     int expandable, int required);

  struct compunit_symtab *end_symtab_from_static_block
      (struct block *static_block, int section, int expandable);

  struct compunit_symtab *end_symtab (CORE_ADDR end_addr, int section);

  struct compunit_symtab *end_expandable_symtab (CORE_ADDR end_addr,
						 int section);

  void augment_type_symtab ();

private:

  void record_pending_block (struct block *block, struct pending_block *opblock);

  struct block *finish_block_internal (struct symbol *symbol,
				       struct pending **listhead,
				       struct pending_block *old_blocks,
				       const struct dynamic_prop *static_link,
				       CORE_ADDR start, CORE_ADDR end,
				       int is_global, int expandable);

  struct blockvector *make_blockvector ();

  void watch_main_source_file_lossage ();

  struct compunit_symtab *end_symtab_with_blockvector
      (struct block *static_block, int section, int expandable);

  /* The objfile we're reading debug info from.  */
  struct objfile *m_objfile;

  /* List of subfiles (source files).
     Files are added to the front of the list.
     This is important mostly for the language determination hacks we use,
     which iterate over previously added files.  */
  struct subfile *m_subfiles = nullptr;

  /* The subfile of the main source file.  */
  struct subfile *m_main_subfile = nullptr;

  /* Name of source file whose symbol data we are now processing.  This
     comes from a symbol of type N_SO for stabs.  For DWARF it comes
     from the DW_AT_name attribute of a DW_TAG_compile_unit DIE.  */
  gdb::unique_xmalloc_ptr<char> m_last_source_file;

  /* E.g., DW_AT_comp_dir if DWARF.  Space for this is malloc'd.  */
  gdb::unique_xmalloc_ptr<char> m_comp_dir;

  /* Space for this is not malloc'd, and is assumed to have at least
     the same lifetime as objfile.  */
  const char *m_producer = nullptr;

  /* Space for this is not malloc'd, and is assumed to have at least
     the same lifetime as objfile.  */
  const char *m_debugformat = nullptr;

  /* The compunit we are building.  */
  struct compunit_symtab *m_compunit_symtab = nullptr;

  /* Language of this compunit_symtab.  */
  enum language m_language;

  /* The macro table for the compilation unit whose symbols we're
     currently reading.  */
  struct macro_table *m_pending_macros = nullptr;

  /* True if symtab has line number info.  This prevents an otherwise
     empty symtab from being tossed.  */
  bool m_have_line_numbers = false;

  /* Core address of start of text of current source file.  This too
     comes from the N_SO symbol.  For Dwarf it typically comes from the
     DW_AT_low_pc attribute of a DW_TAG_compile_unit DIE.  */
  CORE_ADDR m_last_source_start_addr;

  /* Stack of subfile names.  */
  std::vector<const char *> m_subfile_stack;

  /* The "using" directives local to lexical context.  */
  struct using_direct *m_local_using_directives = nullptr;

  /* Global "using" directives.  */
  struct using_direct *m_global_using_directives = nullptr;

  /* The stack of contexts that are pushed by push_context and popped
     by pop_context.  */
  std::vector<struct context_stack> m_context_stack;

  struct subfile *m_current_subfile = nullptr;

  /* The mutable address map for the compilation unit whose symbols
     we're currently reading.  The symtabs' shared blockvector will
     point to a fixed copy of this.  */
  struct addrmap *m_pending_addrmap = nullptr;

  /* The obstack on which we allocate pending_addrmap.
     If pending_addrmap is NULL, this is uninitialized; otherwise, it is
     initialized (and holds pending_addrmap).  */
  auto_obstack m_pending_addrmap_obstack;

  /* True if we recorded any ranges in the addrmap that are different
     from those in the blockvector already.  We set this to false when
     we start processing a symfile, and if it's still false at the
     end, then we just toss the addrmap.  */
  bool m_pending_addrmap_interesting = false;

  /* An obstack used for allocating pending blocks.  */
  auto_obstack m_pending_block_obstack;

  /* Pointer to the head of a linked list of symbol blocks which have
     already been finalized (lexical contexts already closed) and which
     are just waiting to be built into a blockvector when finalizing the
     associated symtab.  */
  struct pending_block *m_pending_blocks = nullptr;

  /* Pending static symbols and types at the top level.  */
  struct pending *m_file_symbols = nullptr;

  /* Pending global functions and variables.  */
  struct pending *m_global_symbols = nullptr;

  /* Pending symbols that are local to the lexical context.  */
  struct pending *m_local_symbols = nullptr;
};



extern void add_symbol_to_list (struct symbol *symbol,
				struct pending **listhead);

extern struct symbol *find_symbol_in_list (struct pending *list,
					   char *name, int length);

#endif /* defined (BUILDSYM_H) */
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/* Implementation of the GDB variable objects API.

   Copyright (C) 1999-2019 Free Software Foundation, Inc.

   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 "value.h"
#include "expression.h"
#include "frame.h"
#include "language.h"
#include "gdbcmd.h"
#include "block.h"
#include "valprint.h"
#include "gdb_regex.h"

#include "varobj.h"
#include "common/vec.h"
#include "gdbthread.h"
#include "inferior.h"
#include "varobj-iter.h"
#include "parser-defs.h"

#if HAVE_PYTHON
#include "python/python.h"
#include "python/python-internal.h"
#else
typedef int PyObject;
#endif

/* Non-zero if we want to see trace of varobj level stuff.  */

unsigned int varobjdebug = 0;
static void
show_varobjdebug (struct ui_file *file, int from_tty,
		  struct cmd_list_element *c, const char *value)
{
  fprintf_filtered (file, _("Varobj debugging is %s.\n"), value);
}

/* String representations of gdb's format codes.  */
const char *varobj_format_string[] =
  { "natural", "binary", "decimal", "hexadecimal", "octal", "zero-hexadecimal" };

/* True if we want to allow Python-based pretty-printing.  */
static bool pretty_printing = false;

void
varobj_enable_pretty_printing (void)
{
  pretty_printing = true;
}

/* Data structures */

/* Every root variable has one of these structures saved in its
   varobj.  */
struct varobj_root
{
  /* The expression for this parent.  */
  expression_up exp;

  /* Block for which this expression is valid.  */
  const struct block *valid_block = NULL;

  /* The frame for this expression.  This field is set iff valid_block is
     not NULL.  */
  struct frame_id frame = null_frame_id;

  /* The global thread ID that this varobj_root belongs to.  This field
     is only valid if valid_block is not NULL.
     When not 0, indicates which thread 'frame' belongs to.
     When 0, indicates that the thread list was empty when the varobj_root
     was created.  */
  int thread_id = 0;

  /* If true, the -var-update always recomputes the value in the
     current thread and frame.  Otherwise, variable object is
     always updated in the specific scope/thread/frame.  */
  bool floating = false;

  /* Flag that indicates validity: set to false when this varobj_root refers
     to symbols that do not exist anymore.  */
  bool is_valid = true;

  /* Language-related operations for this variable and its
     children.  */
  const struct lang_varobj_ops *lang_ops = NULL;

  /* The varobj for this root node.  */
  struct varobj *rootvar = NULL;

  /* Next root variable */
  struct varobj_root *next = NULL;
};

/* Dynamic part of varobj.  */

struct varobj_dynamic
{
  /* Whether the children of this varobj were requested.  This field is
     used to decide if dynamic varobj should recompute their children.
     In the event that the frontend never asked for the children, we
     can avoid that.  */
  bool children_requested = false;

  /* The pretty-printer constructor.  If NULL, then the default
     pretty-printer will be looked up.  If None, then no
     pretty-printer will be installed.  */
  PyObject *constructor = NULL;

  /* The pretty-printer that has been constructed.  If NULL, then a
     new printer object is needed, and one will be constructed.  */
  PyObject *pretty_printer = NULL;

  /* The iterator returned by the printer's 'children' method, or NULL
     if not available.  */
  struct varobj_iter *child_iter = NULL;

  /* We request one extra item from the iterator, so that we can
     report to the caller whether there are more items than we have
     already reported.  However, we don't want to install this value
     when we read it, because that will mess up future updates.  So,
     we stash it here instead.  */
  varobj_item *saved_item = NULL;
};

/* A list of varobjs */

struct vlist
{
  struct varobj *var;
  struct vlist *next;
};

/* Private function prototypes */

/* Helper functions for the above subcommands.  */

static int delete_variable (struct varobj *, bool);

static void delete_variable_1 (int *, struct varobj *, bool, bool);

static bool install_variable (struct varobj *);

static void uninstall_variable (struct varobj *);

static struct varobj *create_child (struct varobj *, int, std::string &);

static struct varobj *
create_child_with_value (struct varobj *parent, int index,
			 struct varobj_item *item);

/* Utility routines */

static enum varobj_display_formats variable_default_display (struct varobj *);

static bool update_type_if_necessary (struct varobj *var,
				      struct value *new_value);

static bool install_new_value (struct varobj *var, struct value *value,
			       bool initial);

/* Language-specific routines.  */

static int number_of_children (const struct varobj *);

static std::string name_of_variable (const struct varobj *);

static std::string name_of_child (struct varobj *, int);

static struct value *value_of_root (struct varobj **var_handle, bool *);

static struct value *value_of_child (const struct varobj *parent, int index);

static std::string my_value_of_variable (struct varobj *var,
					 enum varobj_display_formats format);

static bool is_root_p (const struct varobj *var);

static struct varobj *varobj_add_child (struct varobj *var,
					struct varobj_item *item);

/* Private data */

/* Mappings of varobj_display_formats enums to gdb's format codes.  */
static int format_code[] = { 0, 't', 'd', 'x', 'o', 'z' };

/* Header of the list of root variable objects.  */
static struct varobj_root *rootlist;

/* Prime number indicating the number of buckets in the hash table.  */
/* A prime large enough to avoid too many collisions.  */
#define VAROBJ_TABLE_SIZE 227

/* Pointer to the varobj hash table (built at run time).  */
static struct vlist **varobj_table;



/* API Implementation */
static bool
is_root_p (const struct varobj *var)
{
  return (var->root->rootvar == var);
}

#ifdef HAVE_PYTHON

/* See python-internal.h.  */
gdbpy_enter_varobj::gdbpy_enter_varobj (const struct varobj *var)
: gdbpy_enter (var->root->exp->gdbarch, var->root->exp->language_defn)
{
}

#endif

/* Return the full FRAME which corresponds to the given CORE_ADDR
   or NULL if no FRAME on the chain corresponds to CORE_ADDR.  */

static struct frame_info *
find_frame_addr_in_frame_chain (CORE_ADDR frame_addr)
{
  struct frame_info *frame = NULL;

  if (frame_addr == (CORE_ADDR) 0)
    return NULL;

  for (frame = get_current_frame ();
       frame != NULL;
       frame = get_prev_frame (frame))
    {
      /* The CORE_ADDR we get as argument was parsed from a string GDB
	 output as $fp.  This output got truncated to gdbarch_addr_bit.
	 Truncate the frame base address in the same manner before
	 comparing it against our argument.  */
      CORE_ADDR frame_base = get_frame_base_address (frame);
      int addr_bit = gdbarch_addr_bit (get_frame_arch (frame));

      if (addr_bit < (sizeof (CORE_ADDR) * HOST_CHAR_BIT))
	frame_base &= ((CORE_ADDR) 1 << addr_bit) - 1;

      if (frame_base == frame_addr)
	return frame;
    }

  return NULL;
}

/* Creates a varobj (not its children).  */

struct varobj *
varobj_create (const char *objname,
	       const char *expression, CORE_ADDR frame, enum varobj_type type)
{
  /* Fill out a varobj structure for the (root) variable being constructed.  */
  std::unique_ptr<varobj> var (new varobj (new varobj_root));

  if (expression != NULL)
    {
      struct frame_info *fi;
      struct frame_id old_id = null_frame_id;
      const struct block *block;
      const char *p;
      struct value *value = NULL;
      CORE_ADDR pc;

      /* Parse and evaluate the expression, filling in as much of the
         variable's data as possible.  */

      if (has_stack_frames ())
	{
	  /* Allow creator to specify context of variable.  */
	  if ((type == USE_CURRENT_FRAME) || (type == USE_SELECTED_FRAME))
	    fi = get_selected_frame (NULL);
	  else
	    /* FIXME: cagney/2002-11-23: This code should be doing a
	       lookup using the frame ID and not just the frame's
	       ``address''.  This, of course, means an interface
	       change.  However, with out that interface change ISAs,
	       such as the ia64 with its two stacks, won't work.
	       Similar goes for the case where there is a frameless
	       function.  */
	    fi = find_frame_addr_in_frame_chain (frame);
	}
      else
	fi = NULL;

      if (type == USE_SELECTED_FRAME)
	var->root->floating = true;

      pc = 0;
      block = NULL;
      if (fi != NULL)
	{
	  block = get_frame_block (fi, 0);
	  pc = get_frame_pc (fi);
	}

      p = expression;
      innermost_block.reset (INNERMOST_BLOCK_FOR_SYMBOLS
			     | INNERMOST_BLOCK_FOR_REGISTERS);
      /* Wrap the call to parse expression, so we can 
         return a sensible error.  */
      TRY
	{
	  var->root->exp = parse_exp_1 (&p, pc, block, 0);
	}

      CATCH (except, RETURN_MASK_ERROR)
	{
	  return NULL;
	}
      END_CATCH

      /* Don't allow variables to be created for types.  */
      if (var->root->exp->elts[0].opcode == OP_TYPE
	  || var->root->exp->elts[0].opcode == OP_TYPEOF
	  || var->root->exp->elts[0].opcode == OP_DECLTYPE)
	{
	  fprintf_unfiltered (gdb_stderr, "Attempt to use a type name"
			      " as an expression.\n");
	  return NULL;
	}

      var->format = variable_default_display (var.get ());
      var->root->valid_block =
	var->root->floating ? NULL : innermost_block.block ();
      var->name = expression;
      /* For a root var, the name and the expr are the same.  */
      var->path_expr = expression;

      /* When the frame is different from the current frame, 
         we must select the appropriate frame before parsing
         the expression, otherwise the value will not be current.
         Since select_frame is so benign, just call it for all cases.  */
      if (var->root->valid_block)
	{
	  /* User could specify explicit FRAME-ADDR which was not found but
	     EXPRESSION is frame specific and we would not be able to evaluate
	     it correctly next time.  With VALID_BLOCK set we must also set
	     FRAME and THREAD_ID.  */
	  if (fi == NULL)
	    error (_("Failed to find the specified frame"));

	  var->root->frame = get_frame_id (fi);
	  var->root->thread_id = inferior_thread ()->global_num;
	  old_id = get_frame_id (get_selected_frame (NULL));
	  select_frame (fi);	 
	}

      /* We definitely need to catch errors here.
         If evaluate_expression succeeds we got the value we wanted.
         But if it fails, we still go on with a call to evaluate_type().  */
      TRY
	{
	  value = evaluate_expression (var->root->exp.get ());
	}
      CATCH (except, RETURN_MASK_ERROR)
	{
	  /* Error getting the value.  Try to at least get the
	     right type.  */
	  struct value *type_only_value = evaluate_type (var->root->exp.get ());

	  var->type = value_type (type_only_value);
	}
      END_CATCH

      if (value != NULL)
	{
	  int real_type_found = 0;

	  var->type = value_actual_type (value, 0, &real_type_found);
	  if (real_type_found)
	    value = value_cast (var->type, value);
	}

      /* Set language info */
      var->root->lang_ops = var->root->exp->language_defn->la_varobj_ops;

      install_new_value (var.get (), value, 1 /* Initial assignment */);

      /* Set ourselves as our root.  */
      var->root->rootvar = var.get ();

      /* Reset the selected frame.  */
      if (frame_id_p (old_id))
	select_frame (frame_find_by_id (old_id));
    }

  /* If the variable object name is null, that means this
     is a temporary variable, so don't install it.  */

  if ((var != NULL) && (objname != NULL))
    {
      var->obj_name = objname;

      /* If a varobj name is duplicated, the install will fail so
         we must cleanup.  */
      if (!install_variable (var.get ()))
	return NULL;
    }

  return var.release ();
}

/* Generates an unique name that can be used for a varobj.  */

std::string
varobj_gen_name (void)
{
  static int id = 0;

  /* Generate a name for this object.  */
  id++;
  return string_printf ("var%d", id);
}

/* Given an OBJNAME, returns the pointer to the corresponding varobj.  Call
   error if OBJNAME cannot be found.  */

struct varobj *
varobj_get_handle (const char *objname)
{
  struct vlist *cv;
  const char *chp;
  unsigned int index = 0;
  unsigned int i = 1;

  for (chp = objname; *chp; chp++)
    {
      index = (index + (i++ * (unsigned int) *chp)) % VAROBJ_TABLE_SIZE;
    }

  cv = *(varobj_table + index);
  while (cv != NULL && cv->var->obj_name != objname)
    cv = cv->next;

  if (cv == NULL)
    error (_("Variable object not found"));

  return cv->var;
}

/* Given the handle, return the name of the object.  */

const char *
varobj_get_objname (const struct varobj *var)
{
  return var->obj_name.c_str ();
}

/* Given the handle, return the expression represented by the
   object.  */

std::string
varobj_get_expression (const struct varobj *var)
{
  return name_of_variable (var);
}

/* See varobj.h.  */

int
varobj_delete (struct varobj *var, bool only_children)
{
  return delete_variable (var, only_children);
}

#if HAVE_PYTHON

/* Convenience function for varobj_set_visualizer.  Instantiate a
   pretty-printer for a given value.  */
static PyObject *
instantiate_pretty_printer (PyObject *constructor, struct value *value)
{
  PyObject *val_obj = NULL; 
  PyObject *printer;

  val_obj = value_to_value_object (value);
  if (! val_obj)
    return NULL;

  printer = PyObject_CallFunctionObjArgs (constructor, val_obj, NULL);
  Py_DECREF (val_obj);
  return printer;
}

#endif

/* Set/Get variable object display format.  */

enum varobj_display_formats
varobj_set_display_format (struct varobj *var,
			   enum varobj_display_formats format)
{
  switch (format)
    {
    case FORMAT_NATURAL:
    case FORMAT_BINARY:
    case FORMAT_DECIMAL:
    case FORMAT_HEXADECIMAL:
    case FORMAT_OCTAL:
    case FORMAT_ZHEXADECIMAL:
      var->format = format;
      break;

    default:
      var->format = variable_default_display (var);
    }

  if (varobj_value_is_changeable_p (var) 
      && var->value != nullptr && !value_lazy (var->value.get ()))
    {
      var->print_value = varobj_value_get_print_value (var->value.get (),
						       var->format, var);
    }

  return var->format;
}

enum varobj_display_formats
varobj_get_display_format (const struct varobj *var)
{
  return var->format;
}

gdb::unique_xmalloc_ptr<char>
varobj_get_display_hint (const struct varobj *var)
{
  gdb::unique_xmalloc_ptr<char> result;

#if HAVE_PYTHON
  if (!gdb_python_initialized)
    return NULL;

  gdbpy_enter_varobj enter_py (var);

  if (var->dynamic->pretty_printer != NULL)
    result = gdbpy_get_display_hint (var->dynamic->pretty_printer);
#endif

  return result;
}

/* Return true if the varobj has items after TO, false otherwise.  */

bool
varobj_has_more (const struct varobj *var, int to)
{
  if (var->children.size () > to)
    return true;

  return ((to == -1 || var->children.size () == to)
	  && (var->dynamic->saved_item != NULL));
}

/* If the variable object is bound to a specific thread, that
   is its evaluation can always be done in context of a frame
   inside that thread, returns GDB id of the thread -- which
   is always positive.  Otherwise, returns -1.  */
int
varobj_get_thread_id (const struct varobj *var)
{
  if (var->root->valid_block && var->root->thread_id > 0)
    return var->root->thread_id;
  else
    return -1;
}

void
varobj_set_frozen (struct varobj *var, bool frozen)
{
  /* When a variable is unfrozen, we don't fetch its value.
     The 'not_fetched' flag remains set, so next -var-update
     won't complain.

     We don't fetch the value, because for structures the client
     should do -var-update anyway.  It would be bad to have different
     client-size logic for structure and other types.  */
  var->frozen = frozen;
}

bool
varobj_get_frozen (const struct varobj *var)
{
  return var->frozen;
}

/* A helper function that restricts a range to what is actually
   available in a VEC.  This follows the usual rules for the meaning
   of FROM and TO -- if either is negative, the entire range is
   used.  */

void
varobj_restrict_range (const std::vector<varobj *> &children,
		       int *from, int *to)
{
  int len = children.size ();

  if (*from < 0 || *to < 0)
    {
      *from = 0;
      *to = len;
    }
  else
    {
      if (*from > len)
	*from = len;
      if (*to > len)
	*to = len;
      if (*from > *to)
	*from = *to;
    }
}

/* A helper for update_dynamic_varobj_children that installs a new
   child when needed.  */

static void
install_dynamic_child (struct varobj *var,
		       std::vector<varobj *> *changed,
		       std::vector<varobj *> *type_changed,
		       std::vector<varobj *> *newobj,
		       std::vector<varobj *> *unchanged,
		       bool *cchanged,
		       int index,
		       struct varobj_item *item)
{
  if (var->children.size () < index + 1)
    {
      /* There's no child yet.  */
      struct varobj *child = varobj_add_child (var, item);

      if (newobj != NULL)
	{
	  newobj->push_back (child);
	  *cchanged = true;
	}
    }
  else
    {
      varobj *existing = var->children[index];
      bool type_updated = update_type_if_necessary (existing, item->value);

      if (type_updated)
	{
	  if (type_changed != NULL)
	    type_changed->push_back (existing);
	}
      if (install_new_value (existing, item->value, 0))
	{
	  if (!type_updated && changed != NULL)
	    changed->push_back (existing);
	}
      else if (!type_updated && unchanged != NULL)
	unchanged->push_back (existing);
    }
}

#if HAVE_PYTHON

static bool
dynamic_varobj_has_child_method (const struct varobj *var)
{
  PyObject *printer = var->dynamic->pretty_printer;

  if (!gdb_python_initialized)
    return false;

  gdbpy_enter_varobj enter_py (var);
  return PyObject_HasAttr (printer, gdbpy_children_cst);
}
#endif

/* A factory for creating dynamic varobj's iterators.  Returns an
   iterator object suitable for iterating over VAR's children.  */

static struct varobj_iter *
varobj_get_iterator (struct varobj *var)
{
#if HAVE_PYTHON
  if (var->dynamic->pretty_printer)
    return py_varobj_get_iterator (var, var->dynamic->pretty_printer);
#endif

  gdb_assert_not_reached (_("\
requested an iterator from a non-dynamic varobj"));
}

/* Release and clear VAR's saved item, if any.  */

static void
varobj_clear_saved_item (struct varobj_dynamic *var)
{
  if (var->saved_item != NULL)
    {
      value_decref (var->saved_item->value);
      delete var->saved_item;
      var->saved_item = NULL;
    }
}

static bool
update_dynamic_varobj_children (struct varobj *var,
				std::vector<varobj *> *changed,
				std::vector<varobj *> *type_changed,
				std::vector<varobj *> *newobj,
				std::vector<varobj *> *unchanged,
				bool *cchanged,
				bool update_children,
				int from,
				int to)
{
  int i;

  *cchanged = false;

  if (update_children || var->dynamic->child_iter == NULL)
    {
      varobj_iter_delete (var->dynamic->child_iter);
      var->dynamic->child_iter = varobj_get_iterator (var);

      varobj_clear_saved_item (var->dynamic);

      i = 0;

      if (var->dynamic->child_iter == NULL)
	return false;
    }
  else
    i = var->children.size ();

  /* We ask for one extra child, so that MI can report whether there
     are more children.  */
  for (; to < 0 || i < to + 1; ++i)
    {
      varobj_item *item;

      /* See if there was a leftover from last time.  */
      if (var->dynamic->saved_item != NULL)
	{
	  item = var->dynamic->saved_item;
	  var->dynamic->saved_item = NULL;
	}
      else
	{
	  item = varobj_iter_next (var->dynamic->child_iter);
	  /* Release vitem->value so its lifetime is not bound to the
	     execution of a command.  */
	  if (item != NULL && item->value != NULL)
	    release_value (item->value).release ();
	}

      if (item == NULL)
	{
	  /* Iteration is done.  Remove iterator from VAR.  */
	  varobj_iter_delete (var->dynamic->child_iter);
	  var->dynamic->child_iter = NULL;
	  break;
	}
      /* We don't want to push the extra child on any report list.  */
      if (to < 0 || i < to)
	{
	  bool can_mention = from < 0 || i >= from;

	  install_dynamic_child (var, can_mention ? changed : NULL,
				 can_mention ? type_changed : NULL,
				 can_mention ? newobj : NULL,
				 can_mention ? unchanged : NULL,
				 can_mention ? cchanged : NULL, i,
				 item);

	  delete item;
	}
      else
	{
	  var->dynamic->saved_item = item;

	  /* We want to truncate the child list just before this
	     element.  */
	  break;
	}
    }

  if (i < var->children.size ())
    {
      *cchanged = true;
      for (int j = i; j < var->children.size (); ++j)
	varobj_delete (var->children[j], 0);

      var->children.resize (i);
    }

  /* If there are fewer children than requested, note that the list of
     children changed.  */
  if (to >= 0 && var->children.size () < to)
    *cchanged = true;

  var->num_children = var->children.size ();

  return true;
}

int
varobj_get_num_children (struct varobj *var)
{
  if (var->num_children == -1)
    {
      if (varobj_is_dynamic_p (var))
	{
	  bool dummy;

	  /* If we have a dynamic varobj, don't report -1 children.
	     So, try to fetch some children first.  */
	  update_dynamic_varobj_children (var, NULL, NULL, NULL, NULL, &dummy,
					  false, 0, 0);
	}
      else
	var->num_children = number_of_children (var);
    }

  return var->num_children >= 0 ? var->num_children : 0;
}

/* Creates a list of the immediate children of a variable object;
   the return code is the number of such children or -1 on error.  */

const std::vector<varobj *> &
varobj_list_children (struct varobj *var, int *from, int *to)
{
  var->dynamic->children_requested = true;

  if (varobj_is_dynamic_p (var))
    {
      bool children_changed;

      /* This, in theory, can result in the number of children changing without
	 frontend noticing.  But well, calling -var-list-children on the same
	 varobj twice is not something a sane frontend would do.  */
      update_dynamic_varobj_children (var, NULL, NULL, NULL, NULL,
				      &children_changed, false, 0, *to);
      varobj_restrict_range (var->children, from, to);
      return var->children;
    }

  if (var->num_children == -1)
    var->num_children = number_of_children (var);

  /* If that failed, give up.  */
  if (var->num_children == -1)
    return var->children;

  /* If we're called when the list of children is not yet initialized,
     allocate enough elements in it.  */
  while (var->children.size () < var->num_children)
    var->children.push_back (NULL);

  for (int i = 0; i < var->num_children; i++)
    {
      if (var->children[i] == NULL)
	{
	  /* Either it's the first call to varobj_list_children for
	     this variable object, and the child was never created,
	     or it was explicitly deleted by the client.  */
	  std::string name = name_of_child (var, i);
	  var->children[i] = create_child (var, i, name);
	}
    }

  varobj_restrict_range (var->children, from, to);
  return var->children;
}

static struct varobj *
varobj_add_child (struct varobj *var, struct varobj_item *item)
{
  varobj *v = create_child_with_value (var, var->children.size (), item);

  var->children.push_back (v);

  return v;
}

/* Obtain the type of an object Variable as a string similar to the one gdb
   prints on the console.  The caller is responsible for freeing the string.
   */

std::string
varobj_get_type (struct varobj *var)
{
  /* For the "fake" variables, do not return a type.  (Its type is
     NULL, too.)
     Do not return a type for invalid variables as well.  */
  if (CPLUS_FAKE_CHILD (var) || !var->root->is_valid)
    return std::string ();

  return type_to_string (var->type);
}

/* Obtain the type of an object variable.  */

struct type *
varobj_get_gdb_type (const struct varobj *var)
{
  return var->type;
}

/* Is VAR a path expression parent, i.e., can it be used to construct
   a valid path expression?  */

static bool
is_path_expr_parent (const struct varobj *var)
{
  gdb_assert (var->root->lang_ops->is_path_expr_parent != NULL);
  return var->root->lang_ops->is_path_expr_parent (var);
}

/* Is VAR a path expression parent, i.e., can it be used to construct
   a valid path expression?  By default we assume any VAR can be a path
   parent.  */

bool
varobj_default_is_path_expr_parent (const struct varobj *var)
{
  return true;
}

/* Return the path expression parent for VAR.  */

const struct varobj *
varobj_get_path_expr_parent (const struct varobj *var)
{
  const struct varobj *parent = var;

  while (!is_root_p (parent) && !is_path_expr_parent (parent))
    parent = parent->parent;

  /* Computation of full rooted expression for children of dynamic
     varobjs is not supported.  */
  if (varobj_is_dynamic_p (parent))
    error (_("Invalid variable object (child of a dynamic varobj)"));

  return parent;
}

/* Return a pointer to the full rooted expression of varobj VAR.
   If it has not been computed yet, compute it.  */

const char *
varobj_get_path_expr (const struct varobj *var)
{
  if (var->path_expr.empty ())
    {
      /* For root varobjs, we initialize path_expr
	 when creating varobj, so here it should be
	 child varobj.  */
      struct varobj *mutable_var = (struct varobj *) var;
      gdb_assert (!is_root_p (var));

      mutable_var->path_expr = (*var->root->lang_ops->path_expr_of_child) (var);
    }

  return var->path_expr.c_str ();
}

const struct language_defn *
varobj_get_language (const struct varobj *var)
{
  return var->root->exp->language_defn;
}

int
varobj_get_attributes (const struct varobj *var)
{
  int attributes = 0;

  if (varobj_editable_p (var))
    /* FIXME: define masks for attributes.  */
    attributes |= 0x00000001;	/* Editable */

  return attributes;
}

/* Return true if VAR is a dynamic varobj.  */

bool
varobj_is_dynamic_p (const struct varobj *var)
{
  return var->dynamic->pretty_printer != NULL;
}

std::string
varobj_get_formatted_value (struct varobj *var,
			    enum varobj_display_formats format)
{
  return my_value_of_variable (var, format);
}

std::string
varobj_get_value (struct varobj *var)
{
  return my_value_of_variable (var, var->format);
}

/* Set the value of an object variable (if it is editable) to the
   value of the given expression.  */
/* Note: Invokes functions that can call error().  */

bool
varobj_set_value (struct varobj *var, const char *expression)
{
  struct value *val = NULL; /* Initialize to keep gcc happy.  */
  /* The argument "expression" contains the variable's new value.
     We need to first construct a legal expression for this -- ugh!  */
  /* Does this cover all the bases?  */
  struct value *value = NULL; /* Initialize to keep gcc happy.  */
  int saved_input_radix = input_radix;
  const char *s = expression;

  gdb_assert (varobj_editable_p (var));

  input_radix = 10;		/* ALWAYS reset to decimal temporarily.  */
  expression_up exp = parse_exp_1 (&s, 0, 0, 0);
  TRY
    {
      value = evaluate_expression (exp.get ());
    }

  CATCH (except, RETURN_MASK_ERROR)
    {
      /* We cannot proceed without a valid expression.  */
      return false;
    }
  END_CATCH

  /* All types that are editable must also be changeable.  */
  gdb_assert (varobj_value_is_changeable_p (var));

  /* The value of a changeable variable object must not be lazy.  */
  gdb_assert (!value_lazy (var->value.get ()));

  /* Need to coerce the input.  We want to check if the
     value of the variable object will be different
     after assignment, and the first thing value_assign
     does is coerce the input.
     For example, if we are assigning an array to a pointer variable we
     should compare the pointer with the array's address, not with the
     array's content.  */
  value = coerce_array (value);

  /* The new value may be lazy.  value_assign, or
     rather value_contents, will take care of this.  */
  TRY
    {
      val = value_assign (var->value.get (), value);
    }

  CATCH (except, RETURN_MASK_ERROR)
    {
      return false;
    }
  END_CATCH

  /* If the value has changed, record it, so that next -var-update can
     report this change.  If a variable had a value of '1', we've set it
     to '333' and then set again to '1', when -var-update will report this
     variable as changed -- because the first assignment has set the
     'updated' flag.  There's no need to optimize that, because return value
     of -var-update should be considered an approximation.  */
  var->updated = install_new_value (var, val, false /* Compare values.  */);
  input_radix = saved_input_radix;
  return true;
}

#if HAVE_PYTHON

/* A helper function to install a constructor function and visualizer
   in a varobj_dynamic.  */

static void
install_visualizer (struct varobj_dynamic *var, PyObject *constructor,
		    PyObject *visualizer)
{
  Py_XDECREF (var->constructor);
  var->constructor = constructor;

  Py_XDECREF (var->pretty_printer);
  var->pretty_printer = visualizer;

  varobj_iter_delete (var->child_iter);
  var->child_iter = NULL;
}

/* Install the default visualizer for VAR.  */

static void
install_default_visualizer (struct varobj *var)
{
  /* Do not install a visualizer on a CPLUS_FAKE_CHILD.  */
  if (CPLUS_FAKE_CHILD (var))
    return;

  if (pretty_printing)
    {
      gdbpy_ref<> pretty_printer;

      if (var->value != nullptr)
	{
	  pretty_printer = gdbpy_get_varobj_pretty_printer (var->value.get ());
	  if (pretty_printer == nullptr)
	    {
	      gdbpy_print_stack ();
	      error (_("Cannot instantiate printer for default visualizer"));
	    }
	}

      if (pretty_printer == Py_None)
	pretty_printer.release ();
  
      install_visualizer (var->dynamic, NULL, pretty_printer.release ());
    }
}

/* Instantiate and install a visualizer for VAR using CONSTRUCTOR to
   make a new object.  */

static void
construct_visualizer (struct varobj *var, PyObject *constructor)
{
  PyObject *pretty_printer;

  /* Do not install a visualizer on a CPLUS_FAKE_CHILD.  */
  if (CPLUS_FAKE_CHILD (var))
    return;

  Py_INCREF (constructor);
  if (constructor == Py_None)
    pretty_printer = NULL;
  else
    {
      pretty_printer = instantiate_pretty_printer (constructor,
						   var->value.get ());
      if (! pretty_printer)
	{
	  gdbpy_print_stack ();
	  Py_DECREF (constructor);
	  constructor = Py_None;
	  Py_INCREF (constructor);
	}

      if (pretty_printer == Py_None)
	{
	  Py_DECREF (pretty_printer);
	  pretty_printer = NULL;
	}
    }

  install_visualizer (var->dynamic, constructor, pretty_printer);
}

#endif /* HAVE_PYTHON */

/* A helper function for install_new_value.  This creates and installs
   a visualizer for VAR, if appropriate.  */

static void
install_new_value_visualizer (struct varobj *var)
{
#if HAVE_PYTHON
  /* If the constructor is None, then we want the raw value.  If VAR
     does not have a value, just skip this.  */
  if (!gdb_python_initialized)
    return;

  if (var->dynamic->constructor != Py_None && var->value != NULL)
    {
      gdbpy_enter_varobj enter_py (var);

      if (var->dynamic->constructor == NULL)
	install_default_visualizer (var);
      else
	construct_visualizer (var, var->dynamic->constructor);
    }
#else
  /* Do nothing.  */
#endif
}

/* When using RTTI to determine variable type it may be changed in runtime when
   the variable value is changed.  This function checks whether type of varobj
   VAR will change when a new value NEW_VALUE is assigned and if it is so
   updates the type of VAR.  */

static bool
update_type_if_necessary (struct varobj *var, struct value *new_value)
{
  if (new_value)
    {
      struct value_print_options opts;

      get_user_print_options (&opts);
      if (opts.objectprint)
	{
	  struct type *new_type = value_actual_type (new_value, 0, 0);
	  std::string new_type_str = type_to_string (new_type);
	  std::string curr_type_str = varobj_get_type (var);

	  /* Did the type name change?  */
	  if (curr_type_str != new_type_str)
	    {
	      var->type = new_type;

	      /* This information may be not valid for a new type.  */
	      varobj_delete (var, 1);
	      var->children.clear ();
	      var->num_children = -1;
	      return true;
	    }
	}
    }

  return false;
}

/* Assign a new value to a variable object.  If INITIAL is true,
   this is the first assignment after the variable object was just
   created, or changed type.  In that case, just assign the value 
   and return false.
   Otherwise, assign the new value, and return true if the value is
   different from the current one, false otherwise.  The comparison is
   done on textual representation of value.  Therefore, some types
   need not be compared.  E.g.  for structures the reported value is
   always "{...}", so no comparison is necessary here.  If the old
   value was NULL and new one is not, or vice versa, we always return true.

   The VALUE parameter should not be released -- the function will
   take care of releasing it when needed.  */
static bool
install_new_value (struct varobj *var, struct value *value, bool initial)
{ 
  bool changeable;
  bool need_to_fetch;
  bool changed = false;
  bool intentionally_not_fetched = false;

  /* We need to know the varobj's type to decide if the value should
     be fetched or not.  C++ fake children (public/protected/private)
     don't have a type.  */
  gdb_assert (var->type || CPLUS_FAKE_CHILD (var));
  changeable = varobj_value_is_changeable_p (var);

  /* If the type has custom visualizer, we consider it to be always
     changeable.  FIXME: need to make sure this behaviour will not
     mess up read-sensitive values.  */
  if (var->dynamic->pretty_printer != NULL)
    changeable = true;

  need_to_fetch = changeable;

  /* We are not interested in the address of references, and given
     that in C++ a reference is not rebindable, it cannot
     meaningfully change.  So, get hold of the real value.  */
  if (value)
    value = coerce_ref (value);

  if (var->type && TYPE_CODE (var->type) == TYPE_CODE_UNION)
    /* For unions, we need to fetch the value implicitly because
       of implementation of union member fetch.  When gdb
       creates a value for a field and the value of the enclosing
       structure is not lazy,  it immediately copies the necessary
       bytes from the enclosing values.  If the enclosing value is
       lazy, the call to value_fetch_lazy on the field will read
       the data from memory.  For unions, that means we'll read the
       same memory more than once, which is not desirable.  So
       fetch now.  */
    need_to_fetch = true;

  /* The new value might be lazy.  If the type is changeable,
     that is we'll be comparing values of this type, fetch the
     value now.  Otherwise, on the next update the old value
     will be lazy, which means we've lost that old value.  */
  if (need_to_fetch && value && value_lazy (value))
    {
      const struct varobj *parent = var->parent;
      bool frozen = var->frozen;

      for (; !frozen && parent; parent = parent->parent)
	frozen |= parent->frozen;

      if (frozen && initial)
	{
	  /* For variables that are frozen, or are children of frozen
	     variables, we don't do fetch on initial assignment.
	     For non-initial assignemnt we do the fetch, since it means we're
	     explicitly asked to compare the new value with the old one.  */
	  intentionally_not_fetched = true;
	}
      else
	{

	  TRY
	    {
	      value_fetch_lazy (value);
	    }

	  CATCH (except, RETURN_MASK_ERROR)
	    {
	      /* Set the value to NULL, so that for the next -var-update,
		 we don't try to compare the new value with this value,
		 that we couldn't even read.  */
	      value = NULL;
	    }
	  END_CATCH
	}
    }

  /* Get a reference now, before possibly passing it to any Python
     code that might release it.  */
  value_ref_ptr value_holder;
  if (value != NULL)
    value_holder = value_ref_ptr::new_reference (value);

  /* Below, we'll be comparing string rendering of old and new
     values.  Don't get string rendering if the value is
     lazy -- if it is, the code above has decided that the value
     should not be fetched.  */
  std::string print_value;
  if (value != NULL && !value_lazy (value)
      && var->dynamic->pretty_printer == NULL)
    print_value = varobj_value_get_print_value (value, var->format, var);

  /* If the type is changeable, compare the old and the new values.
     If this is the initial assignment, we don't have any old value
     to compare with.  */
  if (!initial && changeable)
    {
      /* If the value of the varobj was changed by -var-set-value,
	 then the value in the varobj and in the target is the same.
	 However, that value is different from the value that the
	 varobj had after the previous -var-update.  So need to the
	 varobj as changed.  */
      if (var->updated)
	changed = true;
      else if (var->dynamic->pretty_printer == NULL)
	{
	  /* Try to compare the values.  That requires that both
	     values are non-lazy.  */
	  if (var->not_fetched && value_lazy (var->value.get ()))
	    {