Add gdb.Value.format_string ()

The str () function, called on a gdb.Value instance, produces a string
representation similar to what can be achieved with the print command,
but it doesn't allow to specify additional formatting settings, for
instance disabling pretty printers.

This patch introduces a new format_string () method to gdb.Value which
allows specifying more formatting options, thus giving access to more
features provided by the internal C function common_val_print ().

gdb/ChangeLog:

2019-04-01  Marco Barisione  <mbarisione@undo.io>

	Add gdb.Value.format_string ().
	* python/py-value.c (copy_py_bool_obj):
	(valpy_format_string): Add gdb.Value.format_string ().
	* NEWS: Document the addition of gdb.Value.format_string ().

gdb/doc/ChangeLog:

2019-04-01  Marco Barisione  <mbarisione@undo.io>

	* python.texi (Values From Inferior): Document
	gdb.Value.format_string ().

gdb/testsuite/ChangeLog:

2019-04-01  Marco Barisione  <mbarisione@undo.io>

	Test gdb.Value.format_string ().
	* gdb.python/py-format-string.exp: New test.
	* gdb.python/py-format-string.c: New file.
	* gdb.python/py-format-string.py: New file.

6 files changed, 1377 insertions, 0 deletions

diff --git a/gdb/NEWS b/gdb/NEWS
index 4bfa15b..dc9e7b3 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -16,6 +16,15 @@
 
 * Support for Pointer Authentication on AArch64 Linux.
 
+* Python API
+
+  ** The gdb.Value type has a new method 'format_string' which returns a
+     string representing the value.  The formatting is controlled by the
+     optional keyword arguments: 'raw', 'pretty_arrays', 'pretty_structs',
+     'array_indexes', 'symbols', 'unions', 'deref_refs', 'actual_objects',
+     'static_members', 'max_elements', 'repeat_threshold', and 'format'.
+
+
 *** Changes in GDB 8.3
 
 * GDB and GDBserver now support access to additional registers on
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 56c925d..67165ac 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -864,6 +864,86 @@ Like @code{Value.cast}, but works as if the C@t{++} @code{reinterpret_cast}
 operator were used.  Consult a C@t{++} reference for details.
 @end defun
 
+@defun Value.format_string (...)
+Convert a @code{gdb.Value} to a string, similarly to what the @code{print}
+command does.  Invoked with no arguments, this is equivalent to calling
+the @code{str} function on the @code{gdb.Value}.  The representation of
+the same value may change across different versions of @value{GDBN}, so
+you shouldn't, for instance, parse the strings returned by this method.
+
+All the arguments are keyword only.  If an argument is not specified, the
+current global default setting is used.
+
+@table @code
+@item raw
+@code{True} if pretty-printers (@pxref{Pretty Printing}) should not be
+used to format the value.  @code{False} if enabled pretty-printers
+matching the type represented by the @code{gdb.Value} should be used to
+format it.
+
+@item pretty_arrays
+@code{True} if arrays should be pretty printed to be more convenient to
+read, @code{False} if they shouldn't (see @code{set print array} in
+@ref{Print Settings}).
+
+@item pretty_structs
+@code{True} if structs should be pretty printed to be more convenient to
+read, @code{False} if they shouldn't (see @code{set print pretty} in
+@ref{Print Settings}).
+
+@item array_indexes
+@code{True} if array indexes should be included in the string
+representation of arrays, @code{False} if they shouldn't (see @code{set
+print array-indexes} in @ref{Print Settings}).
+
+@item symbols
+@code{True} if the string representation of a pointer should include the
+corresponding symbol name (if one exists), @code{False} if it shouldn't
+(see @code{set print symbol} in @ref{Print Settings}).
+
+@item unions
+@code{True} if unions which are contained in other structures or unions
+should be expanded, @code{False} if they shouldn't (see @code{set print
+union} in @ref{Print Settings}).
+
+@item deref_refs
+@code{True} if C@t{++} references should be resolved to the value they
+refer to, @code{False} (the default) if they shouldn't.  Note that, unlike
+for the @code{print} command, references are not automatically expanded
+when using the @code{format_string} method or the @code{str}
+function.  There is no global @code{print} setting to change the default
+behaviour.
+
+@item actual_objects
+@code{True} if the representation of a pointer to an object should
+identify the @emph{actual} (derived) type of the object rather than the
+@emph{declared} type, using the virtual function table.  @code{False} if
+the @emph{declared} type should be used.  (See @code{set print object} in
+@ref{Print Settings}).
+
+@item static_fields
+@code{True} if static members should be included in the string
+representation of a C@t{++} object, @code{False} if they shouldn't (see
+@code{set print static-members} in @ref{Print Settings}).
+
+@item max_elements
+Number of array elements to print, or @code{0} to print an unlimited
+number of elements (see @code{set print elements} in @ref{Print
+Settings}).
+
+@item repeat_threshold
+Set the threshold for suppressing display of repeated array elements, or
+@code{0} to represent all elements, even if repeated.  (See @code{set
+print repeats} in @ref{Print Settings}).
+
+@item format
+A string containing a single character representing the format to use for
+the returned string.  For instance, @code{'x'} is equivalent to using the
+@value{GDBN} command @code{print} with the @code{/x} option and formats
+the value as a hexadecimal number.
+@end table
+@end defun
+
 @defun Value.string (@r{[}encoding@r{[}, errors@r{[}, length@r{]]]})
 If this @code{gdb.Value} represents a string, then this method
 converts the contents to a Python string.  Otherwise, this method will
diff --git a/gdb/python/py-value.c b/gdb/python/py-value.c
index dd6a536..1dcb60d 100644
--- a/gdb/python/py-value.c
+++ b/gdb/python/py-value.c
@@ -588,6 +588,165 @@ valpy_string (PyObject *self, PyObject *args, PyObject *kw)
 			   encoding, errors);
 }
 
+/* Given a Python object, copy its truth value to a C int (the value
+   pointed by dest).
+   If src_obj is NULL, then *dest is not modified.
+
+   Return true in case of success (including src_obj being NULL), false
+   in case of error.  */
+
+static bool
+copy_py_bool_obj (int *dest, PyObject *src_obj)
+{
+  if (src_obj)
+    {
+      int cmp = PyObject_IsTrue (src_obj);
+      if (cmp < 0)
+	return false;
+      *dest = cmp;
+    }
+
+  return true;
+}
+
+/* Implementation of gdb.Value.format_string (...) -> string.
+   Return Unicode string with value contents formatted using the
+   keyword-only arguments.  */
+
+static PyObject *
+valpy_format_string (PyObject *self, PyObject *args, PyObject *kw)
+{
+  static const char *keywords[] =
+    {
+      /* Basic C/C++ options.  */
+      "raw",			/* See the /r option to print.  */
+      "pretty_arrays",		/* See set print array on|off.  */
+      "pretty_structs",		/* See set print pretty on|off.  */
+      "array_indexes",		/* See set print array-indexes on|off.  */
+      "symbols",		/* See set print symbol on|off.  */
+      "unions",			/* See set print union on|off.  */
+      /* C++ options.  */
+      "deref_refs",		/* No corresponding setting.  */
+      "actual_objects",		/* See set print object on|off.  */
+      "static_members",		/* See set print static-members on|off.  */
+      /* C non-bool options.  */
+      "max_elements", 		/* See set print elements N.  */
+      "repeat_threshold",	/* See set print repeats.  */
+      "format",			/* The format passed to the print command.  */
+      NULL
+    };
+
+  /* This function has too many arguments to be useful as positionals, so
+     the user should specify them all as keyword arguments.
+     Python 3.3 and later have a way to specify it (both in C and Python
+     itself), but we could be compiled with older versions, so we just
+     check that the args tuple is empty.  */
+  Py_ssize_t positional_count = PyObject_Length (args);
+  if (positional_count < 0)
+    return NULL;
+  else if (positional_count > 0)
+    {
+      /* This matches the error message that Python 3.3 raises when
+	 passing positionals to functions expecting keyword-only
+	 arguments.  */
+      PyErr_Format (PyExc_TypeError,
+		    "format_string() takes 0 positional arguments but %zu were given",
+		    positional_count);
+      return NULL;
+    }
+
+  struct value_print_options opts;
+  get_user_print_options (&opts);
+  opts.deref_ref = 0;
+
+  /* We need objects for booleans as the "p" flag for bools is new in
+     Python 3.3.  */
+  PyObject *raw_obj = NULL;
+  PyObject *pretty_arrays_obj = NULL;
+  PyObject *pretty_structs_obj = NULL;
+  PyObject *array_indexes_obj = NULL;
+  PyObject *symbols_obj = NULL;
+  PyObject *unions_obj = NULL;
+  PyObject *deref_refs_obj = NULL;
+  PyObject *actual_objects_obj = NULL;
+  PyObject *static_members_obj = NULL;
+  char *format = NULL;
+  if (!gdb_PyArg_ParseTupleAndKeywords (args,
+					kw,
+					"|O!O!O!O!O!O!O!O!O!IIs",
+					keywords,
+					&PyBool_Type, &raw_obj,
+					&PyBool_Type, &pretty_arrays_obj,
+					&PyBool_Type, &pretty_structs_obj,
+					&PyBool_Type, &array_indexes_obj,
+					&PyBool_Type, &symbols_obj,
+					&PyBool_Type, &unions_obj,
+					&PyBool_Type, &deref_refs_obj,
+					&PyBool_Type, &actual_objects_obj,
+					&PyBool_Type, &static_members_obj,
+					&opts.print_max,
+					&opts.repeat_count_threshold,
+					&format))
+    return NULL;
+
+  /* Set boolean arguments.  */
+  if (!copy_py_bool_obj (&opts.raw, raw_obj))
+    return NULL;
+  if (!copy_py_bool_obj (&opts.prettyformat_arrays, pretty_arrays_obj))
+    return NULL;
+  if (!copy_py_bool_obj (&opts.prettyformat_structs, pretty_structs_obj))
+    return NULL;
+  if (!copy_py_bool_obj (&opts.print_array_indexes, array_indexes_obj))
+    return NULL;
+  if (!copy_py_bool_obj (&opts.symbol_print, symbols_obj))
+    return NULL;
+  if (!copy_py_bool_obj (&opts.unionprint, unions_obj))
+    return NULL;
+  if (!copy_py_bool_obj (&opts.deref_ref, deref_refs_obj))
+    return NULL;
+  if (!copy_py_bool_obj (&opts.objectprint, actual_objects_obj))
+    return NULL;
+  if (!copy_py_bool_obj (&opts.static_field_print, static_members_obj))
+    return NULL;
+
+  /* Numeric arguments for which 0 means unlimited (which we represent as
+     UINT_MAX).  */
+  if (opts.print_max == 0)
+    opts.print_max = UINT_MAX;
+  if (opts.repeat_count_threshold == 0)
+    opts.repeat_count_threshold = UINT_MAX;
+
+  /* Other arguments.  */
+  if (format != NULL)
+    {
+      if (strlen (format) == 1)
+	opts.format = format[0];
+      else
+	{
+	  /* Mimic the message on standard Python ones for similar
+	     errors.  */
+	  PyErr_SetString (PyExc_ValueError,
+			   "a single character is required");
+	  return NULL;
+	}
+    }
+
+  string_file stb;
+
+  TRY
+    {
+      common_val_print (((value_object *) self)->value, &stb, 0,
+			&opts, python_language);
+    }
+  CATCH (except, RETURN_MASK_ALL)
+    {
+      GDB_PY_HANDLE_EXCEPTION (except);
+    }
+  END_CATCH
+
+  return PyUnicode_Decode (stb.c_str (), stb.size (), host_charset (), NULL);
+}
+
 /* A helper function that implements the various cast operators.  */
 
 static PyObject *
@@ -1944,6 +2103,11 @@ Return a lazy string representation of the value." },
 Return Unicode string representation of the value." },
   { "fetch_lazy", valpy_fetch_lazy, METH_NOARGS,
     "Fetches the value from the inferior, if it was lazy." },
+  { "format_string", (PyCFunction) valpy_format_string,
+    METH_VARARGS | METH_KEYWORDS,
+    "format_string (...) -> string\n\
+Return a string representation of the value using the specified\n\
+formatting options" },
   {NULL}  /* Sentinel */
 };
 
diff --git a/gdb/testsuite/gdb.python/py-format-string.c b/gdb/testsuite/gdb.python/py-format-string.c
new file mode 100644
index 0000000..120ecce
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-format-string.c
@@ -0,0 +1,118 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 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/>.  */
+
+typedef struct point
+{
+  int x;
+  int y;
+} point_t;
+
+typedef union
+{
+  int an_int;
+  char a_char;
+} union_t;
+
+typedef struct
+{
+  union_t the_union;
+} struct_union_t;
+
+typedef enum
+{
+  ENUM_FOO,
+  ENUM_BAR,
+} enum_t;
+
+typedef void (*function_t) (int);
+
+static void
+my_function(int n)
+{
+}
+
+#ifdef __cplusplus
+
+struct Base
+{
+  Base (int a_) : a (a_) {}
+
+  virtual int get_number () { return a; }
+
+  int a;
+
+  static int a_static_member;
+};
+
+int Base::a_static_member = 2019;
+
+struct Deriv : Base
+{
+  Deriv (int b_) : Base (42), b (b_) {}
+
+  virtual int get_number () { return b; }
+
+  int b;
+};
+
+#endif
+
+int global_symbol = 42;
+
+int
+main ()
+{
+  point_t a_point_t = { 42, 12 };
+  point_t *a_point_t_pointer = &a_point_t;
+#ifdef __cplusplus
+  point_t &a_point_t_ref = a_point_t;
+#endif
+  struct point another_point = { 123, 456 };
+
+  struct_union_t a_struct_with_union;
+  a_struct_with_union.the_union.an_int = 42;
+
+  enum_t an_enum = ENUM_BAR;
+
+  const char *a_string = "hello world";
+  const char *a_binary_string = "hello\0world";
+  const char a_binary_string_array[] = "hello\0world";
+
+  const int letters_repeat = 10;
+  char a_big_string[26 * letters_repeat + 1];
+  a_big_string[26 * letters_repeat] = '\0';
+  for (int i = 0; i < letters_repeat; i++)
+    for (char c = 'A'; c <= 'Z'; c++)
+      a_big_string[i * 26 + c - 'A'] = c;
+
+  int an_array[] = { 2, 3, 5 };
+
+  int an_array_with_repetition[] = {
+    1,					/*  1 time.   */
+    3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,	/* 12 times.  */
+    5, 5, 5,				/*  3 times   */
+    };
+
+  int *a_symbol_pointer = &global_symbol;
+
+#ifdef __cplusplus
+  Deriv a_deriv (123);
+  Base &a_base_ref = a_deriv;
+#endif
+
+  return 0; /* break here */
+}
diff --git a/gdb/testsuite/gdb.python/py-format-string.exp b/gdb/testsuite/gdb.python/py-format-string.exp
new file mode 100644
index 0000000..2f574fb
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-format-string.exp
@@ -0,0 +1,957 @@
+# Copyright (C) 2009-2019 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/>.
+
+# This file is part of the GDB testsuite.  It tests the
+# gdb.Value.format_string () method.
+
+load_lib gdb-python.exp
+
+standard_testfile
+
+if [get_compiler_info c++] {
+    return -1
+}
+
+# Build inferior to language specification.
+proc build_inferior {exefile lang} {
+  global srcdir subdir srcfile testfile hex
+
+  if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${exefile}" executable "debug $lang"] != "" } {
+      untested "failed to compile in $lang mode"
+      return -1
+  }
+
+  return 0
+}
+
+# Restart GDB.
+proc prepare_gdb {exefile} {
+  global srcdir subdir srcfile testfile hex
+
+  gdb_exit
+  gdb_start
+  gdb_reinitialize_dir $srcdir/$subdir
+  gdb_load ${exefile}
+
+  # Skip all tests if Python scripting is not enabled.
+  if { [skip_python_tests] } { continue }
+
+  if ![runto_main] then {
+      perror "couldn't run to breakpoint"
+      return
+  }
+
+  # Load the pretty printer.
+  set remote_python_file \
+    [gdb_remote_download host ${srcdir}/${subdir}/${testfile}.py]
+  gdb_test_no_output "source ${remote_python_file}" "load python file"
+
+  runto_bp "break here"
+}
+
+# Set breakpoint and run to that breakpoint.
+proc runto_bp {bp} {
+  gdb_breakpoint [gdb_get_line_number $bp]
+  gdb_continue_to_breakpoint $bp
+}
+
+# Set an option using the GDB command in $set_cmd, execute $body, and then
+# restore the option using the GDB command in $unset_cmd.
+proc with_temp_option { set_cmd unset_cmd body } {
+  with_test_prefix $set_cmd {
+    gdb_test "$set_cmd" ".*"
+    uplevel 1 $body
+    gdb_test "$unset_cmd" ".*"
+  }
+}
+
+# A regular expression for a pointer.
+set default_pointer_regexp "0x\[a-fA-F0-9\]+"
+
+# A regular expression for a non-expanded C++ reference.
+#
+# Stringifying a C++ reference produces an address preceeded by a "@" in
+# Python, but, by default, the C++ reference/class is expanded by the
+# GDB print command.
+set default_ref_regexp "@${default_pointer_regexp}"
+
+# The whole content of the C variable a_big_string, i.e. the whole English
+# alphabet repeated 10 times.
+set whole_big_string ""
+set alphabet "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+for {set i 0} {$i < 10} {incr i} {
+  append whole_big_string $alphabet
+}
+unset alphabet
+
+# Produces a potentially cut down version of $whole_big_string like GDB
+# would represent it.
+# $max is the maximum number of characters allowed in the string (but
+# the return value may contain more to accound for the extra quotes and
+# "..." added by GDB).
+proc get_cut_big_string { max } {
+  global whole_big_string
+
+  set whole_size [string length $whole_big_string]
+  if { $max > $whole_size } {
+    return "\"${whole_big_string}\""
+  }
+
+  set cut_string [string range $whole_big_string 0 [expr $max - 1]]
+  return "\"${cut_string}\"..."
+}
+
+# A dictionary mapping from C variable names to their default string
+# representation when using str () or gdb.Value.format_string () with
+# no arguments.
+# This usually matches what the print command prints if used with no
+# options, except for C++ references which are not expanded by
+# default in Python.  See the comment above $default_ref_regexp.
+set default_regexp_dict [dict create \
+  "a_point_t"			"Pretty Point \\(42, 12\\)" \
+  "a_point_t_pointer"		$default_pointer_regexp \
+  "a_point_t_ref"		"Pretty Point \\(42, 12\\)" \
+  "another_point"		"Pretty Point \\(123, 456\\)" \
+  "a_struct_with_union"		"\\{the_union = \\{an_int = 42, a_char = 42 '\\*'\\}\\}" \
+  "an_enum"			"ENUM_BAR" \
+  "a_string"			"${default_pointer_regexp} \"hello world\"" \
+  "a_binary_string"		"${default_pointer_regexp} \"hello\"" \
+  "a_binary_string_array"	"\"hello\\\\000world\"" \
+  "a_big_string"		[get_cut_big_string 200] \
+  "an_array"			"\\{2, 3, 5\\}" \
+  "an_array_with_repetition"	"\\{1, 3 <repeats 12 times>, 5, 5, 5\\}" \
+  "a_symbol_pointer"		"${default_pointer_regexp} <global_symbol>" \
+  "a_base_ref"			"${default_ref_regexp}" \
+  ]
+
+# A sentinel value to pass to function to get them to use a default value
+# instead.
+# Note that we cannot use $undefined for default arguments in function
+# definitions as we would just get the literal "$undefined" string, so
+# we need to repeat the string.
+set undefined "\000UNDEFINED\000"
+
+# Return $value if it's not $undefined, otherwise return the default value
+# (from $default_regexp_dict) for the variable $var.
+proc get_value_or_default { var value } {
+  global undefined
+  if { $value != $undefined } {
+    return $value
+  }
+
+  global default_regexp_dict
+  return [dict get $default_regexp_dict $var]
+}
+
+# Check that using gdb.Value.format_string on the value representing the
+# variable $var produces $expected.
+proc check_format_string {
+	var
+	opts
+	{ expected "\000UNDEFINED\000" }
+	{ name "\000UNDEFINED\000" }
+  } {
+  global undefined
+
+  set expected [get_value_or_default $var $expected]
+  if { $name == $undefined } {
+    set name "${var} with option ${opts}"
+  }
+
+  gdb_test \
+    "python print (gdb.parse_and_eval ('${var}').format_string (${opts}))" \
+    $expected \
+    $name
+}
+
+# Check that printing $var with no options set, produces the expected
+# output.
+proc check_var_with_no_opts {
+	var
+	{ expected "\000UNDEFINED\000" }
+  } {
+  set expected [get_value_or_default $var $expected]
+
+  with_test_prefix "${var}" {
+    check_format_string \
+      $var \
+      "" \
+      $expected \
+      "no opts"
+    # str () should behave like gdb.Value.format_string () with no args.
+    gdb_test \
+      "python print (str (gdb.parse_and_eval ('${var}')))" \
+      $expected \
+      "str"
+  }
+}
+
+# Check that printing $var with $opt set to True and set to False,
+# produces the expected output.
+proc check_var_with_bool_opt {
+	opt
+	var
+	{ true_expected  "\000UNDEFINED\000" }
+	{ false_expected "\000UNDEFINED\000" }
+  } {
+  set true_expected  [get_value_or_default $var $true_expected]
+  set false_expected [get_value_or_default $var $false_expected]
+
+  with_test_prefix "${var} with option ${opt}" {
+    # Option set to True.
+    check_format_string \
+      $var \
+      "${opt}=True" \
+      $true_expected \
+      "${opt}=true"
+    # Option set to False.
+    check_format_string \
+      $var \
+      "${opt}=False" \
+      $false_expected \
+      "${opt}=false"
+  }
+}
+
+# Test gdb.Value.format_string with no options.
+proc test_no_opts {} {
+  global current_lang
+
+  check_var_with_no_opts "a_point_t"
+  check_var_with_no_opts "a_point_t_pointer"
+  check_var_with_no_opts "another_point"
+  check_var_with_no_opts "a_struct_with_union"
+  check_var_with_no_opts "an_enum"
+  check_var_with_no_opts "a_string"
+  check_var_with_no_opts "a_binary_string"
+  check_var_with_no_opts "a_binary_string_array"
+  check_var_with_no_opts "a_big_string"
+  check_var_with_no_opts "an_array"
+  check_var_with_no_opts "an_array_with_repetition"
+  check_var_with_no_opts "a_symbol_pointer"
+
+  if { $current_lang == "c++" } {
+    # Nothing changes in all of the C++ tests because deref_refs is not
+    # True.
+    check_var_with_no_opts "a_point_t_ref"
+    check_var_with_no_opts "a_base_ref"
+  }
+}
+
+# Test the raw option for gdb.Value.format_string.
+proc test_raw {} {
+  global current_lang
+  global default_ref_regexp
+
+  check_var_with_bool_opt "raw" "a_point_t" \
+    "{x = 42, y = 12}"
+  check_var_with_bool_opt "raw" "a_point_t_pointer"
+  check_var_with_bool_opt "raw" "another_point" \
+    "{x = 123, y = 456}"
+  check_var_with_bool_opt "raw" "a_struct_with_union"
+  check_var_with_bool_opt "raw" "an_enum"
+  check_var_with_bool_opt "raw" "a_string"
+  check_var_with_bool_opt "raw" "a_binary_string"
+  check_var_with_bool_opt "raw" "a_binary_string_array"
+  check_var_with_bool_opt "raw" "a_big_string"
+  check_var_with_bool_opt "raw" "an_array"
+  check_var_with_bool_opt "raw" "an_array_with_repetition"
+  check_var_with_bool_opt "raw" "a_symbol_pointer"
+
+  if { $current_lang == "c++" } {
+    check_var_with_bool_opt "raw" "a_point_t_ref" \
+      ${default_ref_regexp}
+    check_var_with_bool_opt "raw" "a_base_ref"
+  }
+
+  with_temp_option \
+	"disable pretty-printer '' test_lookup_function" \
+	"enable pretty-printer '' test_lookup_function" {
+    check_var_with_no_opts "a_point_t" \
+      "{x = 42, y = 12}"
+    check_var_with_bool_opt "raw" "a_point_t" \
+      "{x = 42, y = 12}" \
+      "{x = 42, y = 12}"
+  }
+}
+
+# Test the pretty_arrays option for gdb.Value.format_string.
+proc test_pretty_arrays {} {
+  global current_lang
+
+  set an_array_pretty "  \\{2,\[\r\n\]+  3,\[\r\n\]+  5\\}"
+  set an_array_with_repetition_pretty \
+    "  \\{1,\[\r\n\]+  3 <repeats 12 times>,\[\r\n\]+  5,\[\r\n\]+  5,\[\r\n\]+  5\\}"
+
+  check_var_with_bool_opt "pretty_arrays" "a_point_t"
+  check_var_with_bool_opt "pretty_arrays" "a_point_t_pointer"
+  check_var_with_bool_opt "pretty_arrays" "another_point"
+  check_var_with_bool_opt "pretty_arrays" "a_struct_with_union"
+  check_var_with_bool_opt "pretty_arrays" "an_enum"
+  check_var_with_bool_opt "pretty_arrays" "a_string"
+  check_var_with_bool_opt "pretty_arrays" "a_binary_string"
+  check_var_with_bool_opt "pretty_arrays" "a_binary_string_array"
+  check_var_with_bool_opt "pretty_arrays" "a_big_string"
+  check_var_with_bool_opt "pretty_arrays" "an_array" \
+    $an_array_pretty
+  check_var_with_bool_opt "pretty_arrays" "an_array_with_repetition" \
+    $an_array_with_repetition_pretty
+  check_var_with_bool_opt "pretty_arrays" "a_symbol_pointer"
+
+  if { $current_lang == "c++" } {
+    check_var_with_bool_opt "pretty_arrays" "a_point_t_ref"
+    check_var_with_bool_opt "pretty_arrays" "a_base_ref"
+  }
+
+  with_temp_option "set print array on" "set print array off" {
+    check_var_with_no_opts "an_array" \
+      $an_array_pretty
+    check_var_with_bool_opt "pretty_arrays" "an_array" \
+      $an_array_pretty
+
+    check_var_with_no_opts "an_array_with_repetition" \
+      $an_array_with_repetition_pretty
+    check_var_with_bool_opt "pretty_arrays" "an_array_with_repetition" \
+      $an_array_with_repetition_pretty
+  }
+}
+
+# Test the pretty_structs option for gdb.Value.format_string.
+proc test_pretty_structs {} {
+  global current_lang
+
+  set a_struct_with_union_pretty \
+    "\\{\[\r\n\]+  the_union = \\{\[\r\n\]+    an_int = 42,\[\r\n\]+    a_char = 42 '\\*'\[\r\n\]+  \\}\[\r\n\]+\\}"
+
+  check_var_with_bool_opt "pretty_structs" "a_point_t"
+  check_var_with_bool_opt "pretty_structs" "a_point_t_pointer"
+  check_var_with_bool_opt "pretty_structs" "another_point"
+  check_var_with_bool_opt "pretty_structs" "a_struct_with_union" \
+    $a_struct_with_union_pretty
+  check_var_with_bool_opt "pretty_structs" "an_enum"
+  check_var_with_bool_opt "pretty_structs" "a_string"
+  check_var_with_bool_opt "pretty_structs" "a_binary_string"
+  check_var_with_bool_opt "pretty_structs" "a_binary_string_array"
+  check_var_with_bool_opt "pretty_structs" "a_big_string"
+  check_var_with_bool_opt "pretty_structs" "an_array"
+  check_var_with_bool_opt "pretty_structs" "an_array_with_repetition"
+  check_var_with_bool_opt "pretty_structs" "a_symbol_pointer"
+
+  if { $current_lang == "c++" } {
+    check_var_with_bool_opt "pretty_structs" "a_point_t_ref"
+    check_var_with_bool_opt "pretty_structs" "a_base_ref"
+  }
+
+  with_temp_option "set print structs on" "set print structs off" {
+    check_var_with_no_opts "a_struct_with_union"
+    check_var_with_bool_opt "pretty_structs" "a_struct_with_union" \
+      $a_struct_with_union_pretty
+  }
+
+  # point_t is usually printed through the pretty printer.
+  # Try disabling it.
+  with_temp_option \
+	"disable pretty-printer '' test_lookup_function" \
+	"enable pretty-printer '' test_lookup_function" {
+    check_var_with_no_opts "a_point_t" \
+      "{x = 42, y = 12}"
+    check_var_with_bool_opt "pretty_structs" "a_point_t" \
+      "\\{\[\r\n\]+  x = 42, *\[\r\n\]+  y = 12\[\r\n\]+\\}" \
+      "{x = 42, y = 12}" \
+  }
+}
+
+# Test the array_indexes option for gdb.Value.format_string.
+proc test_array_indexes {} {
+  global current_lang
+
+  set an_array_with_indexes "\\{\\\[0\\\] = 2, \\\[1\\\] = 3, \\\[2\\\] = 5\\}"
+  set an_array_with_repetition_with_indexes \
+    "\\{\\\[0\\\] = 1, \\\[1\\\] = 3 <repeats 12 times>, \\\[13\\\] = 5, \\\[14\\\] = 5, \\\[15\\\] = 5\\}"
+
+  check_var_with_bool_opt "array_indexes" "a_point_t"
+  check_var_with_bool_opt "array_indexes" "a_point_t_pointer"
+  check_var_with_bool_opt "array_indexes" "another_point"
+  check_var_with_bool_opt "array_indexes" "a_struct_with_union"
+  check_var_with_bool_opt "array_indexes" "an_enum"
+  check_var_with_bool_opt "array_indexes" "a_string"
+  check_var_with_bool_opt "array_indexes" "a_binary_string"
+  check_var_with_bool_opt "array_indexes" "a_binary_string_array"
+  check_var_with_bool_opt "array_indexes" "a_big_string"
+  check_var_with_bool_opt "array_indexes" "an_array" \
+    $an_array_with_indexes
+  check_var_with_bool_opt "array_indexes" "an_array_with_repetition" \
+    $an_array_with_repetition_with_indexes
+  check_var_with_bool_opt "array_indexes" "a_symbol_pointer"
+
+  if { $current_lang == "c++" } {
+    check_var_with_bool_opt "array_indexes" "a_point_t_ref"
+    check_var_with_bool_opt "array_indexes" "a_base_ref"
+  }
+
+  with_temp_option \
+	"set print array-indexes on" \
+	"set print array-indexes off" {
+    check_var_with_no_opts "an_array" \
+      $an_array_with_indexes
+    check_var_with_bool_opt "array_indexes" "an_array" \
+      $an_array_with_indexes
+
+    check_var_with_no_opts "an_array_with_repetition" \
+      $an_array_with_repetition_with_indexes
+    check_var_with_bool_opt "array_indexes" "an_array_with_repetition" \
+      $an_array_with_repetition_with_indexes
+  }
+}
+
+# Test the symbols option for gdb.Value.format_string.
+proc test_symbols {} {
+  global undefined
+  global current_lang
+  global default_pointer_regexp
+
+  check_var_with_bool_opt "symbols" "a_point_t"
+  check_var_with_bool_opt "symbols" "a_point_t_pointer"
+  check_var_with_bool_opt "symbols" "another_point"
+  check_var_with_bool_opt "symbols" "a_struct_with_union"
+  check_var_with_bool_opt "symbols" "an_enum"
+  check_var_with_bool_opt "symbols" "a_string"
+  check_var_with_bool_opt "symbols" "a_binary_string"
+  check_var_with_bool_opt "symbols" "a_binary_string_array"
+  check_var_with_bool_opt "symbols" "a_big_string"
+  check_var_with_bool_opt "symbols" "an_array"
+  check_var_with_bool_opt "symbols" "an_array_with_repetition"
+  check_var_with_bool_opt "symbols" "a_symbol_pointer" \
+    $undefined \
+    $default_pointer_regexp
+
+  if { $current_lang == "c++" } {
+    check_var_with_bool_opt "symbols" "a_point_t_ref"
+    check_var_with_bool_opt "symbols" "a_base_ref"
+  }
+
+  with_temp_option "set print symbol off" "set print symbol on" {
+    check_var_with_no_opts "a_symbol_pointer" \
+      $default_pointer_regexp
+    check_var_with_bool_opt "symbols" "a_symbol_pointer" \
+      $undefined \
+      $default_pointer_regexp
+  }
+}
+
+# Test the unions option for gdb.Value.format_string.
+proc test_unions {} {
+  global undefined
+  global current_lang
+
+  check_var_with_bool_opt "unions" "a_point_t"
+  check_var_with_bool_opt "unions" "a_point_t_pointer"
+  check_var_with_bool_opt "unions" "another_point"
+  check_var_with_bool_opt "unions" "a_struct_with_union" \
+    $undefined \
+    "\\{the_union = \\{...\\}\\}"
+  check_var_with_bool_opt "unions" "an_enum"
+  check_var_with_bool_opt "unions" "a_string"
+  check_var_with_bool_opt "unions" "a_binary_string"
+  check_var_with_bool_opt "unions" "a_binary_string_array"
+  check_var_with_bool_opt "unions" "a_big_string"
+  check_var_with_bool_opt "unions" "an_array"
+  check_var_with_bool_opt "unions" "an_array_with_repetition"
+  check_var_with_bool_opt "unions" "a_symbol_pointer"
+
+  if { $current_lang == "c++" } {
+    check_var_with_bool_opt "unions" "a_point_t_ref"
+    check_var_with_bool_opt "unions" "a_base_ref"
+  }
+
+  with_temp_option "set print union off" "set print union on" {
+    check_var_with_no_opts "a_struct_with_union" \
+      "\\{the_union = \\{...\\}\\}"
+    check_var_with_bool_opt "unions" "a_struct_with_union" \
+      $undefined \
+      "\\{the_union = \\{...\\}\\}"
+  }
+}
+
+# Test the deref_refs option for gdb.Value.format_string.
+proc test_deref_refs {} {
+  global current_lang
+  global default_pointer_regexp
+  global default_ref_regexp
+
+  check_var_with_bool_opt "deref_refs" "a_point_t"
+  check_var_with_bool_opt "deref_refs" "a_point_t_pointer"
+  check_var_with_bool_opt "deref_refs" "another_point"
+  check_var_with_bool_opt "deref_refs" "a_struct_with_union"
+  check_var_with_bool_opt "deref_refs" "an_enum"
+  check_var_with_bool_opt "deref_refs" "a_string"
+  check_var_with_bool_opt "deref_refs" "a_binary_string"
+  check_var_with_bool_opt "deref_refs" "a_binary_string_array"
+  check_var_with_bool_opt "deref_refs" "a_big_string"
+  check_var_with_bool_opt "deref_refs" "an_array"
+  check_var_with_bool_opt "deref_refs" "an_array_with_repetition"
+  check_var_with_bool_opt "deref_refs" "a_symbol_pointer"
+
+  if { $current_lang == "c++" } {
+    check_var_with_bool_opt "deref_refs" "a_point_t_ref"
+    check_var_with_bool_opt "deref_refs" "a_base_ref" \
+      "${default_ref_regexp}: \\{_vptr\\.Base = ${default_pointer_regexp} <vtable for Deriv\\+16>, a = 42, static a_static_member = 2019\\}"
+  }
+}
+
+# Test the actual_objects option for gdb.Value.format_string.
+proc test_actual_objects {} {
+  global current_lang
+
+  check_var_with_bool_opt "actual_objects" "a_point_t"
+  check_var_with_bool_opt "actual_objects" "a_point_t_pointer"
+  check_var_with_bool_opt "actual_objects" "another_point"
+  check_var_with_bool_opt "actual_objects" "a_struct_with_union"
+  check_var_with_bool_opt "actual_objects" "an_enum"
+  check_var_with_bool_opt "actual_objects" "a_string"
+  check_var_with_bool_opt "actual_objects" "a_binary_string"
+  check_var_with_bool_opt "actual_objects" "a_binary_string_array"
+  check_var_with_bool_opt "actual_objects" "a_big_string"
+  check_var_with_bool_opt "actual_objects" "an_array"
+  check_var_with_bool_opt "actual_objects" "an_array_with_repetition"
+  check_var_with_bool_opt "actual_objects" "a_symbol_pointer"
+
+  if { $current_lang == "c++" } {
+    # Nothing changes in all of the C++ tests because deref_refs is not
+    # True.
+    check_var_with_bool_opt "actual_objects" "a_point_t_ref"
+    check_var_with_bool_opt "actual_objects" "a_base_ref"
+
+    with_temp_option "set print object on" "set print object off" {
+      check_var_with_no_opts "a_point_t_ref"
+      check_var_with_bool_opt "actual_objects" "a_point_t_ref"
+
+      check_var_with_no_opts "a_base_ref"
+      check_var_with_bool_opt "actual_objects" "a_base_ref"
+    }
+  }
+}
+
+# Test the static_members option for gdb.Value.format_string.
+proc test_static_members {} {
+  global current_lang
+
+  check_var_with_bool_opt "static_members" "a_point_t"
+  check_var_with_bool_opt "static_members" "a_point_t_pointer"
+  check_var_with_bool_opt "static_members" "another_point"
+  check_var_with_bool_opt "static_members" "a_struct_with_union"
+  check_var_with_bool_opt "static_members" "an_enum"
+  check_var_with_bool_opt "static_members" "a_string"
+  check_var_with_bool_opt "static_members" "a_binary_string"
+  check_var_with_bool_opt "static_members" "a_binary_string_array"
+  check_var_with_bool_opt "static_members" "a_big_string"
+  check_var_with_bool_opt "static_members" "an_array"
+  check_var_with_bool_opt "static_members" "an_array_with_repetition"
+  check_var_with_bool_opt "static_members" "a_symbol_pointer"
+
+  if { $current_lang == "c++" } {
+    # Nothing changes in all of the C++ tests because deref_refs is not
+    # True.
+    check_var_with_bool_opt "static_members" "a_point_t_ref"
+    check_var_with_bool_opt "static_members" "a_base_ref"
+
+    with_temp_option \
+	"set print static-members off" \
+	"set print static-members on" {
+      check_var_with_no_opts "a_point_t_ref"
+      check_var_with_bool_opt "static_members" "a_point_t_ref"
+
+      check_var_with_no_opts "a_base_ref"
+      check_var_with_bool_opt "static_members" "a_base_ref"
+    }
+  }
+}
+
+# Test the max_elements option for gdb.Value.format_string.
+proc test_max_elements {} {
+  global current_lang
+  global default_pointer_regexp
+
+  # 200 is the default maximum number of elements, so setting it should
+  # not change the output.
+  set opts "max_elements=200"
+  with_test_prefix $opts {
+    check_format_string "a_point_t" $opts
+    check_format_string "a_point_t_pointer" $opts
+    check_format_string "another_point" $opts
+    check_format_string "a_struct_with_union" $opts
+    check_format_string "an_enum" $opts
+    check_format_string "a_string" $opts
+    check_format_string "a_binary_string" $opts
+    check_format_string "a_binary_string_array" $opts
+    check_format_string "a_big_string" $opts
+    check_format_string "an_array" $opts
+    check_format_string "an_array_with_repetition" $opts
+    check_format_string "a_symbol_pointer" $opts
+
+    if { $current_lang == "c++" } {
+      check_format_string "a_point_t_ref" $opts
+      check_format_string "a_base_ref" $opts
+    }
+  }
+
+  set opts "max_elements=3"
+  with_test_prefix $opts {
+    check_format_string "a_point_t" $opts
+    check_format_string "a_point_t_pointer" $opts
+    check_format_string "another_point" $opts
+    check_format_string "a_struct_with_union" $opts
+    check_format_string "an_enum" $opts
+    check_format_string "a_string" $opts \
+      "${default_pointer_regexp} \"hel\"..."
+    check_format_string "a_binary_string" $opts \
+      "${default_pointer_regexp} \"hel\"..."
+    # This will print four characters instead of three, see
+    # <https://sourceware.org/bugzilla/show_bug.cgi?id=24331>.
+    check_format_string "a_binary_string_array" $opts \
+      "\"hell\"..."
+    check_format_string "a_big_string" $opts \
+      [get_cut_big_string 3]
+    check_format_string "an_array" $opts
+    check_format_string "an_array_with_repetition" $opts \
+      "\\{1, 3 <repeats 12 times>...\\}"
+    check_format_string "a_symbol_pointer" $opts
+
+    if { $current_lang == "c++" } {
+      check_format_string "a_point_t_ref" $opts
+      check_format_string "a_base_ref" $opts
+    }
+  }
+
+  # Both 1,000 (we don't have that many elements) and 0 (unlimited) should
+  # mean no truncation.
+  foreach opts { "max_elements=1000" "max_elements=0" } {
+    with_test_prefix $opts {
+      check_format_string "a_point_t" $opts
+      check_format_string "a_point_t_pointer" $opts
+      check_format_string "another_point" $opts
+      check_format_string "a_struct_with_union" $opts
+      check_format_string "an_enum" $opts
+      check_format_string "a_string" $opts
+      check_format_string "a_binary_string" $opts
+      check_format_string "a_binary_string_array" $opts
+      check_format_string "a_big_string" $opts \
+        [get_cut_big_string 1000]
+      check_format_string "an_array" $opts
+      check_format_string "an_array_with_repetition" $opts
+      check_format_string "a_symbol_pointer" $opts
+
+      if { $current_lang == "c++" } {
+        check_format_string "a_point_t_ref" $opts
+        check_format_string "a_base_ref" $opts
+      }
+    }
+  }
+
+  with_temp_option "set print elements 4" "set print elements 200" {
+    check_format_string "a_string" "" \
+      "${default_pointer_regexp} \"hell\"..."
+    check_format_string "a_binary_string" "" \
+      "${default_pointer_regexp} \"hell\"..."
+    check_format_string "a_binary_string_array" "" \
+      "\"hell\"..."
+    check_format_string "an_array_with_repetition" "" \
+      "\\{1, 3 <repeats 12 times>...\\}"
+  }
+}
+
+# Test the repeat_threshold option for gdb.Value.format_string.
+proc test_repeat_threshold {} {
+  global current_lang
+  global default_pointer_regexp
+
+  # 10 is the default threshold for repeated items, so setting it should
+  # not change the output.
+  set opts "repeat_threshold=10"
+  with_test_prefix $opts {
+    check_format_string "a_point_t" $opts
+    check_format_string "a_point_t_pointer" $opts
+    check_format_string "another_point" $opts
+    check_format_string "a_struct_with_union" $opts
+    check_format_string "an_enum" $opts
+    check_format_string "a_string" $opts
+    check_format_string "a_binary_string" $opts
+    check_format_string "a_binary_string_array" $opts
+    check_format_string "a_big_string" $opts
+    check_format_string "an_array" $opts
+    check_format_string "an_array_with_repetition" $opts
+    check_format_string "a_symbol_pointer" $opts
+
+    if { $current_lang == "c++" } {
+      check_format_string "a_point_t_ref" $opts
+      check_format_string "a_base_ref" $opts
+    }
+  }
+
+  set opts "repeat_threshold=1"
+  with_test_prefix $opts {
+    check_format_string "a_point_t" $opts
+    check_format_string "a_point_t_pointer" $opts
+    check_format_string "another_point" $opts
+    check_format_string "a_struct_with_union" $opts
+    check_format_string "an_enum" $opts
+    check_format_string "a_string" $opts \
+      "${default_pointer_regexp} \"he\", 'l' <repeats 2 times>, \"o world\""
+    check_format_string "a_binary_string" $opts \
+      "${default_pointer_regexp} \"he\", 'l' <repeats 2 times>, \"o\""
+    check_format_string "a_binary_string_array" $opts \
+      "\"he\", 'l' <repeats 2 times>, \"o\\\\000world\""
+    check_format_string "a_big_string" $opts
+    check_format_string "an_array" $opts
+    check_format_string "an_array_with_repetition" $opts \
+      "\\{1, 3 <repeats 12 times>, 5 <repeats 3 times>\\}"
+
+    check_format_string "a_symbol_pointer" $opts
+
+    if { $current_lang == "c++" } {
+      check_format_string "a_point_t_ref" $opts
+      check_format_string "a_base_ref" $opts
+    }
+  }
+
+  set opts "repeat_threshold=3"
+  with_test_prefix $opts {
+    check_format_string "a_point_t" $opts
+    check_format_string "a_point_t_pointer" $opts
+    check_format_string "another_point" $opts
+    check_format_string "a_struct_with_union" $opts
+    check_format_string "an_enum" $opts
+    check_format_string "a_string" $opts
+    check_format_string "a_binary_string" $opts
+    check_format_string "a_binary_string_array" $opts
+    check_format_string "a_big_string" $opts
+    check_format_string "an_array" $opts
+    check_format_string "an_array_with_repetition" $opts
+    check_format_string "a_symbol_pointer" $opts
+
+    if { $current_lang == "c++" } {
+      check_format_string "a_point_t_ref" $opts
+      check_format_string "a_base_ref" $opts
+    }
+  }
+
+  # Both 100 (we don't have that many repeated elements) and 0 (unlimited)
+  # should mean no truncation.
+  foreach opts { "repeat_threshold=100" "repeat_threshold=0" } {
+    with_test_prefix $opts {
+      check_format_string "a_point_t" $opts
+      check_format_string "a_point_t_pointer" $opts
+      check_format_string "another_point" $opts
+      check_format_string "a_struct_with_union" $opts
+      check_format_string "an_enum" $opts
+      check_format_string "a_string" $opts
+      check_format_string "a_binary_string" $opts
+      check_format_string "a_binary_string_array" $opts
+      check_format_string "a_big_string" $opts
+      check_format_string "an_array" $opts
+      check_format_string "an_array_with_repetition" $opts \
+        "\\{1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 5, 5, 5\\}"
+      check_format_string "a_symbol_pointer" $opts
+
+      if { $current_lang == "c++" } {
+        check_format_string "a_point_t_ref" $opts
+        check_format_string "a_base_ref" $opts
+      }
+    }
+  }
+
+  with_temp_option "set print repeats 1" "set print repeats 10" {
+    check_format_string "an_array_with_repetition" "" \
+      "\\{1, 3 <repeats 12 times>, 5 <repeats 3 times>\\}"
+  }
+}
+
+# Test the format option for gdb.Value.format_string.
+proc test_format {} {
+  global current_lang
+  global default_pointer_regexp
+
+  # Hexadecimal.
+  set opts "format='x'"
+  with_test_prefix $opts {
+    gdb_test "python print (gdb.Value (42).format_string (${opts}))" \
+      "0x2a" \
+      "42 with option ${opts}"
+
+    check_format_string "a_point_t" $opts
+    check_format_string "a_point_t_pointer" $opts
+    check_format_string "another_point" $opts
+    check_format_string "a_struct_with_union" $opts \
+      "\\{the_union = \\{an_int = 0x2a, a_char = 0x2a\\}\\}"
+    check_format_string "an_enum" $opts \
+      "0x1"
+    check_format_string "a_string" $opts \
+      $default_pointer_regexp
+    check_format_string "a_binary_string" $opts \
+      $default_pointer_regexp
+    check_format_string "a_binary_string_array" $opts \
+      "\\{0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x0, 0x77, 0x6f, 0x72, 0x6c, 0x64, 0x0\\}"
+    check_format_string "a_big_string" $opts \
+      "\\{0x41, 0x42, 0x43, 0x44, 0x45, \[, x0-9a-f\]+\.\.\.\\}"
+    check_format_string "an_array" $opts \
+      "\\{0x2, 0x3, 0x5\\}"
+    check_format_string "an_array_with_repetition" $opts \
+      "\\{0x1, 0x3 <repeats 12 times>, 0x5, 0x5, 0x5\\}"
+    check_format_string "a_symbol_pointer" $opts \
+      $default_pointer_regexp
+
+    if { $current_lang == "c++" } {
+      check_format_string "a_point_t_ref" $opts
+      check_format_string "a_base_ref" $opts
+    }
+  }
+
+  # Decimal.
+  set opts "format='d'"
+  with_test_prefix $opts {
+    set decimal_pointer_regexp "\[0-9\]+"
+    gdb_test "python print (gdb.Value (0x2a).format_string (${opts}))" \
+      "42" \
+      "0x2a with option ${opts}"
+
+    check_format_string "a_point_t" $opts
+    check_format_string "a_point_t_pointer" $opts \
+      $decimal_pointer_regexp
+    check_format_string "another_point" $opts
+    check_format_string "a_struct_with_union" $opts \
+      "\\{the_union = \\{an_int = 42, a_char = 42\\}\\}"
+    check_format_string "an_enum" $opts \
+      "1"
+    check_format_string "a_string" $opts \
+      $decimal_pointer_regexp
+    check_format_string "a_binary_string" $opts \
+      $decimal_pointer_regexp
+    check_format_string "a_binary_string_array" $opts \
+      "\\{104, 101, 108, 108, 111, 0, 119, 111, 114, 108, 100, 0\\}"
+    check_format_string "a_big_string" $opts \
+      "\\{65, 66, 67, 68, 69, \[, 0-9\]+\.\.\.\\}"
+    check_format_string "an_array" $opts
+    check_format_string "an_array_with_repetition" $opts
+    check_format_string "a_symbol_pointer" $opts \
+      $decimal_pointer_regexp
+
+    if { $current_lang == "c++" } {
+      check_format_string "a_point_t_ref" $opts
+      check_format_string "a_base_ref" $opts
+    }
+  }
+}
+
+# Test mixing options.
+proc test_mixed {} {
+  global current_lang
+  global default_ref_regexp
+  global default_pointer_regexp
+
+  check_format_string "a_point_t" \
+    "raw=True, format='x'" \
+    "\\{x = 0x2a, y = 0xc\\}"
+
+  check_format_string "an_array" \
+    "array_indexes=True, pretty_arrays=True" \
+    "  \\{\\\[0\\\] = 2,\[\r\n\]+  \\\[1\\\] = 3,\[\r\n\]+  \\\[2\\\] = 5\\}"
+
+  check_format_string "a_struct_with_union" \
+    "pretty_structs=True, unions=False" \
+    "\\{\[\r\n\]+  the_union = \\{\.\.\.\\}\[\r\n\]+\\}"
+
+  check_format_string "a_symbol_pointer" \
+    "symbols=False, format='d'" \
+    "\[0-9\]+"
+
+  if { $current_lang == "c++" } {
+    check_format_string "a_point_t_ref" \
+      "deref_refs=True, actual_objects=True, raw=True" \
+      "${default_ref_regexp}: \\{x = 42, y = 12\\}"
+
+    check_format_string "a_base_ref" \
+      "deref_refs=True, static_members=False" \
+      "${default_ref_regexp}: \\{_vptr\\.Base = ${default_pointer_regexp} <vtable for Deriv\\+16>, a = 42\\}"
+  }
+}
+
+# Test passing invalid arguments to gdb.Value.format_string.
+proc test_invalid_args {} {
+  check_format_string \
+    "a_point_t" \
+    "12" \
+    "TypeError: format_string\\(\\) takes 0 positional arguments but 1 were given.*"
+
+  check_format_string \
+    "a_point_t" \
+    "invalid=True" \
+    "TypeError: 'invalid' is an invalid keyword argument for this function.*"
+
+  check_format_string \
+    "a_point_t" \
+    "raw='hello'" \
+    "TypeError: argument 1 must be bool, not str.*"
+
+  check_format_string \
+    "a_point_t" \
+    "format='xd'" \
+    "ValueError: a single character is required.*"
+}
+
+# Run all the tests in common for both C and C++.
+proc test_all_common {} {
+  # No options.
+  test_no_opts
+  # Single options set to True/False.
+  test_raw
+  test_pretty_arrays
+  test_pretty_structs
+  test_array_indexes
+  test_symbols
+  test_unions
+  test_deref_refs
+  test_actual_objects
+  test_static_members
+  test_max_elements
+  test_repeat_threshold
+  test_format
+  # Multiple options mixed together.
+  test_mixed
+  # Various error conditions.
+  test_invalid_args
+}
+
+# The current language ("c" or "c++" while running tests).
+set current_lang ""
+
+with_test_prefix "format_string" {
+  # Perform C Tests.
+  if { [build_inferior "${binfile}" "c"] == 0 } {
+    with_test_prefix "lang_c" {
+      set current_lang "c"
+      prepare_gdb "${binfile}"
+      test_all_common
+    }
+  }
+
+  # Perform C++ Tests.
+  if { [build_inferior "${binfile}-cxx" "c++"] == 0 } {
+    with_test_prefix "lang_cpp" {
+      set current_lang "c++"
+      prepare_gdb "${binfile}-cxx"
+      test_all_common
+    }
+  }
+}
diff --git a/gdb/testsuite/gdb.python/py-format-string.py b/gdb/testsuite/gdb.python/py-format-string.py
new file mode 100644
index 0000000..c2ad88e
--- /dev/null
+++ b/gdb/testsuite/gdb.python/py-format-string.py
@@ -0,0 +1,49 @@
+# Copyright (C) 2008-2019 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/>.
+
+# This file is part of the GDB testsuite.  It tests python pretty
+# printers.
+
+import gdb
+
+class PointPrinter (object):
+    def __init__ (self, val):
+        self.val = val
+
+    def to_string (self):
+        return 'Pretty Point (%s, %s)' % (self.val['x'], self.val['y'])
+
+def test_lookup_function (val):
+    "Look-up and return a pretty-printer that can print val."
+
+    # Get the type.
+    type = val.type
+
+    # If it points to a reference, get the reference.
+    if type.code == gdb.TYPE_CODE_REF:
+        type = type.target ()
+
+    # Get the unqualified type, stripped of typedefs.
+    type = type.unqualified ().strip_typedefs ()
+
+    # Get the type name.
+    typename = type.tag
+
+    if typename == 'point':
+        return PointPrinter (val)
+
+    return None
+
+gdb.pretty_printers.append (test_lookup_function)