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- /* Support for printing C values for GDB, the GNU debugger.
- Copyright (C) 1986-2022 Free Software Foundation, Inc.
- This file is part of GDB.
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
- #include "defs.h"
- #include "symtab.h"
- #include "gdbtypes.h"
- #include "expression.h"
- #include "value.h"
- #include "valprint.h"
- #include "language.h"
- #include "c-lang.h"
- #include "cp-abi.h"
- #include "target.h"
- #include "objfiles.h"
- /* A helper for c_textual_element_type. This checks the name of the
- typedef. This is bogus but it isn't apparent that the compiler
- provides us the help we may need. */
- static int
- textual_name (const char *name)
- {
- return (!strcmp (name, "wchar_t")
- || !strcmp (name, "char16_t")
- || !strcmp (name, "char32_t"));
- }
- /* Apply a heuristic to decide whether an array of TYPE or a pointer
- to TYPE should be printed as a textual string. Return non-zero if
- it should, or zero if it should be treated as an array of integers
- or pointer to integers. FORMAT is the current format letter, or 0
- if none.
- We guess that "char" is a character. Explicitly signed and
- unsigned character types are also characters. Integer data from
- vector types is not. The user can override this by using the /s
- format letter. */
- int
- c_textual_element_type (struct type *type, char format)
- {
- struct type *true_type, *iter_type;
- if (format != 0 && format != 's')
- return 0;
- /* We also rely on this for its side effect of setting up all the
- typedef pointers. */
- true_type = check_typedef (type);
- /* TYPE_CODE_CHAR is always textual. */
- if (true_type->code () == TYPE_CODE_CHAR)
- return 1;
- /* Any other character-like types must be integral. */
- if (true_type->code () != TYPE_CODE_INT)
- return 0;
- /* We peel typedefs one by one, looking for a match. */
- iter_type = type;
- while (iter_type)
- {
- /* Check the name of the type. */
- if (iter_type->name () && textual_name (iter_type->name ()))
- return 1;
- if (iter_type->code () != TYPE_CODE_TYPEDEF)
- break;
- /* Peel a single typedef. If the typedef doesn't have a target
- type, we use check_typedef and hope the result is ok -- it
- might be for C++, where wchar_t is a built-in type. */
- if (TYPE_TARGET_TYPE (iter_type))
- iter_type = TYPE_TARGET_TYPE (iter_type);
- else
- iter_type = check_typedef (iter_type);
- }
- if (format == 's')
- {
- /* Print this as a string if we can manage it. For now, no wide
- character support. */
- if (true_type->code () == TYPE_CODE_INT
- && TYPE_LENGTH (true_type) == 1)
- return 1;
- }
- else
- {
- /* If a one-byte TYPE_CODE_INT is missing the not-a-character
- flag, then we treat it as text; otherwise, we assume it's
- being used as data. */
- if (true_type->code () == TYPE_CODE_INT
- && TYPE_LENGTH (true_type) == 1
- && !TYPE_NOTTEXT (true_type))
- return 1;
- }
- return 0;
- }
- /* Decorations for C. */
- static const struct generic_val_print_decorations c_decorations =
- {
- "",
- " + ",
- "i",
- "true",
- "false",
- "void",
- "{",
- "}"
- };
- /* Print a pointer based on the type of its target.
- Arguments to this functions are roughly the same as those in c_val_print.
- A difference is that ADDRESS is the address to print, with embedded_offset
- already added. UNRESOLVED_ELTTYPE and ELTTYPE represent the pointed type,
- respectively before and after check_typedef. */
- static void
- print_unpacked_pointer (struct type *type, struct type *elttype,
- struct type *unresolved_elttype,
- const gdb_byte *valaddr, int embedded_offset,
- CORE_ADDR address, struct ui_file *stream, int recurse,
- const struct value_print_options *options)
- {
- int want_space = 0;
- struct gdbarch *gdbarch = type->arch ();
- if (elttype->code () == TYPE_CODE_FUNC)
- {
- /* Try to print what function it points to. */
- print_function_pointer_address (options, gdbarch, address, stream);
- return;
- }
- if (options->symbol_print)
- want_space = print_address_demangle (options, gdbarch, address, stream,
- demangle);
- else if (options->addressprint)
- {
- gdb_puts (paddress (gdbarch, address), stream);
- want_space = 1;
- }
- /* For a pointer to a textual type, also print the string
- pointed to, unless pointer is null. */
- if (c_textual_element_type (unresolved_elttype, options->format)
- && address != 0)
- {
- if (want_space)
- gdb_puts (" ", stream);
- val_print_string (unresolved_elttype, NULL, address, -1, stream, options);
- }
- else if (cp_is_vtbl_member (type))
- {
- /* Print vtbl's nicely. */
- CORE_ADDR vt_address = unpack_pointer (type, valaddr + embedded_offset);
- struct bound_minimal_symbol msymbol =
- lookup_minimal_symbol_by_pc (vt_address);
- /* If 'symbol_print' is set, we did the work above. */
- if (!options->symbol_print
- && (msymbol.minsym != NULL)
- && (vt_address == BMSYMBOL_VALUE_ADDRESS (msymbol)))
- {
- if (want_space)
- gdb_puts (" ", stream);
- gdb_puts (" <", stream);
- gdb_puts (msymbol.minsym->print_name (), stream);
- gdb_puts (">", stream);
- want_space = 1;
- }
- if (vt_address && options->vtblprint)
- {
- struct value *vt_val;
- struct symbol *wsym = NULL;
- struct type *wtype;
- if (want_space)
- gdb_puts (" ", stream);
- if (msymbol.minsym != NULL)
- {
- const char *search_name = msymbol.minsym->search_name ();
- wsym = lookup_symbol_search_name (search_name, NULL,
- VAR_DOMAIN).symbol;
- }
- if (wsym)
- {
- wtype = wsym->type ();
- }
- else
- {
- wtype = unresolved_elttype;
- }
- vt_val = value_at (wtype, vt_address);
- common_val_print (vt_val, stream, recurse + 1, options,
- current_language);
- if (options->prettyformat)
- {
- gdb_printf (stream, "\n");
- print_spaces (2 + 2 * recurse, stream);
- }
- }
- }
- }
- /* c_value_print helper for TYPE_CODE_ARRAY. */
- static void
- c_value_print_array (struct value *val,
- struct ui_file *stream, int recurse,
- const struct value_print_options *options)
- {
- struct type *type = check_typedef (value_type (val));
- CORE_ADDR address = value_address (val);
- const gdb_byte *valaddr = value_contents_for_printing (val).data ();
- struct type *unresolved_elttype = TYPE_TARGET_TYPE (type);
- struct type *elttype = check_typedef (unresolved_elttype);
- if (TYPE_LENGTH (type) > 0 && TYPE_LENGTH (unresolved_elttype) > 0)
- {
- LONGEST low_bound, high_bound;
- int eltlen, len;
- enum bfd_endian byte_order = type_byte_order (type);
- if (!get_array_bounds (type, &low_bound, &high_bound))
- error (_("Could not determine the array high bound"));
- eltlen = TYPE_LENGTH (elttype);
- len = high_bound - low_bound + 1;
- /* Print arrays of textual chars with a string syntax, as
- long as the entire array is valid. */
- if (c_textual_element_type (unresolved_elttype,
- options->format)
- && value_bytes_available (val, 0, TYPE_LENGTH (type))
- && !value_bits_any_optimized_out (val, 0,
- TARGET_CHAR_BIT * TYPE_LENGTH (type)))
- {
- int force_ellipses = 0;
- /* If requested, look for the first null char and only
- print elements up to it. */
- if (options->stop_print_at_null)
- {
- unsigned int temp_len;
- for (temp_len = 0;
- (temp_len < len
- && temp_len < options->print_max
- && extract_unsigned_integer (valaddr + temp_len * eltlen,
- eltlen, byte_order) != 0);
- ++temp_len)
- ;
- /* Force printstr to print ellipses if
- we've printed the maximum characters and
- the next character is not \000. */
- if (temp_len == options->print_max && temp_len < len)
- {
- ULONGEST ival
- = extract_unsigned_integer (valaddr + temp_len * eltlen,
- eltlen, byte_order);
- if (ival != 0)
- force_ellipses = 1;
- }
- len = temp_len;
- }
- current_language->printstr (stream, unresolved_elttype, valaddr, len,
- NULL, force_ellipses, options);
- }
- else
- {
- unsigned int i = 0;
- gdb_printf (stream, "{");
- /* If this is a virtual function table, print the 0th
- entry specially, and the rest of the members
- normally. */
- if (cp_is_vtbl_ptr_type (elttype))
- {
- i = 1;
- gdb_printf (stream, _("%d vtable entries"),
- len - 1);
- }
- value_print_array_elements (val, stream, recurse, options, i);
- gdb_printf (stream, "}");
- }
- }
- else
- {
- /* Array of unspecified length: treat like pointer to first elt. */
- print_unpacked_pointer (type, elttype, unresolved_elttype, valaddr,
- 0, address, stream, recurse, options);
- }
- }
- /* c_value_print_inner helper for TYPE_CODE_PTR. */
- static void
- c_value_print_ptr (struct value *val, struct ui_file *stream, int recurse,
- const struct value_print_options *options)
- {
- if (options->format && options->format != 's')
- {
- value_print_scalar_formatted (val, options, 0, stream);
- return;
- }
- struct type *type = check_typedef (value_type (val));
- const gdb_byte *valaddr = value_contents_for_printing (val).data ();
- if (options->vtblprint && cp_is_vtbl_ptr_type (type))
- {
- /* Print the unmangled name if desired. */
- /* Print vtable entry - we only get here if we ARE using
- -fvtable_thunks. (Otherwise, look under
- TYPE_CODE_STRUCT.) */
- CORE_ADDR addr = extract_typed_address (valaddr, type);
- print_function_pointer_address (options, type->arch (), addr, stream);
- }
- else
- {
- struct type *unresolved_elttype = TYPE_TARGET_TYPE (type);
- struct type *elttype = check_typedef (unresolved_elttype);
- CORE_ADDR addr = unpack_pointer (type, valaddr);
- print_unpacked_pointer (type, elttype, unresolved_elttype, valaddr,
- 0, addr, stream, recurse, options);
- }
- }
- /* c_value_print helper for TYPE_CODE_STRUCT and TYPE_CODE_UNION. */
- static void
- c_value_print_struct (struct value *val, struct ui_file *stream, int recurse,
- const struct value_print_options *options)
- {
- struct type *type = check_typedef (value_type (val));
- if (type->code () == TYPE_CODE_UNION && recurse && !options->unionprint)
- gdb_printf (stream, "{...}");
- else if (options->vtblprint && cp_is_vtbl_ptr_type (type))
- {
- /* Print the unmangled name if desired. */
- /* Print vtable entry - we only get here if NOT using
- -fvtable_thunks. (Otherwise, look under
- TYPE_CODE_PTR.) */
- int offset = type->field (VTBL_FNADDR_OFFSET).loc_bitpos () / 8;
- struct type *field_type = type->field (VTBL_FNADDR_OFFSET).type ();
- const gdb_byte *valaddr = value_contents_for_printing (val).data ();
- CORE_ADDR addr = extract_typed_address (valaddr + offset, field_type);
- print_function_pointer_address (options, type->arch (), addr, stream);
- }
- else
- cp_print_value_fields (val, stream, recurse, options, NULL, 0);
- }
- /* c_value_print helper for TYPE_CODE_INT. */
- static void
- c_value_print_int (struct value *val, struct ui_file *stream,
- const struct value_print_options *options)
- {
- if (options->format || options->output_format)
- {
- struct value_print_options opts = *options;
- opts.format = (options->format ? options->format
- : options->output_format);
- value_print_scalar_formatted (val, &opts, 0, stream);
- }
- else
- {
- value_print_scalar_formatted (val, options, 0, stream);
- /* C and C++ has no single byte int type, char is used
- instead. Since we don't know whether the value is really
- intended to be used as an integer or a character, print
- the character equivalent as well. */
- struct type *type = value_type (val);
- const gdb_byte *valaddr = value_contents_for_printing (val).data ();
- if (c_textual_element_type (type, options->format))
- {
- gdb_puts (" ", stream);
- current_language->printchar (unpack_long (type, valaddr), type,
- stream);
- }
- }
- }
- /* See c-lang.h. */
- void
- c_value_print_inner (struct value *val, struct ui_file *stream, int recurse,
- const struct value_print_options *options)
- {
- struct type *type = value_type (val);
- type = check_typedef (type);
- switch (type->code ())
- {
- case TYPE_CODE_ARRAY:
- c_value_print_array (val, stream, recurse, options);
- break;
- case TYPE_CODE_PTR:
- c_value_print_ptr (val, stream, recurse, options);
- break;
- case TYPE_CODE_UNION:
- case TYPE_CODE_STRUCT:
- c_value_print_struct (val, stream, recurse, options);
- break;
- case TYPE_CODE_CHAR:
- case TYPE_CODE_INT:
- c_value_print_int (val, stream, options);
- break;
- case TYPE_CODE_METHODPTR:
- case TYPE_CODE_MEMBERPTR:
- case TYPE_CODE_REF:
- case TYPE_CODE_RVALUE_REF:
- case TYPE_CODE_ENUM:
- case TYPE_CODE_FLAGS:
- case TYPE_CODE_FUNC:
- case TYPE_CODE_METHOD:
- case TYPE_CODE_BOOL:
- case TYPE_CODE_RANGE:
- case TYPE_CODE_FLT:
- case TYPE_CODE_DECFLOAT:
- case TYPE_CODE_VOID:
- case TYPE_CODE_ERROR:
- case TYPE_CODE_UNDEF:
- case TYPE_CODE_COMPLEX:
- default:
- generic_value_print (val, stream, recurse, options, &c_decorations);
- break;
- }
- }
- void
- c_value_print (struct value *val, struct ui_file *stream,
- const struct value_print_options *options)
- {
- struct type *type, *real_type;
- int full, using_enc;
- LONGEST top;
- struct value_print_options opts = *options;
- opts.deref_ref = 1;
- /* If it is a pointer, indicate what it points to.
- Print type also if it is a reference.
- C++: if it is a member pointer, we will take care
- of that when we print it. */
- type = check_typedef (value_type (val));
- if (type->is_pointer_or_reference ())
- {
- struct type *original_type = value_type (val);
- /* Hack: remove (char *) for char strings. Their
- type is indicated by the quoted string anyway.
- (Don't use c_textual_element_type here; quoted strings
- are always exactly (char *), (wchar_t *), or the like. */
- if (original_type->code () == TYPE_CODE_PTR
- && original_type->name () == NULL
- && TYPE_TARGET_TYPE (original_type)->name () != NULL
- && (strcmp (TYPE_TARGET_TYPE (original_type)->name (),
- "char") == 0
- || textual_name (TYPE_TARGET_TYPE (original_type)->name ())))
- {
- /* Print nothing. */
- }
- else if (options->objectprint
- && (TYPE_TARGET_TYPE (type)->code () == TYPE_CODE_STRUCT))
- {
- int is_ref = TYPE_IS_REFERENCE (type);
- enum type_code refcode = TYPE_CODE_UNDEF;
- if (is_ref)
- {
- val = value_addr (val);
- refcode = type->code ();
- }
- /* Pointer to class, check real type of object. */
- gdb_printf (stream, "(");
- if (value_entirely_available (val))
- {
- real_type = value_rtti_indirect_type (val, &full, &top,
- &using_enc);
- if (real_type)
- {
- /* RTTI entry found. */
- /* Need to adjust pointer value. */
- val = value_from_pointer (real_type,
- value_as_address (val) - top);
- /* Note: When we look up RTTI entries, we don't get
- any information on const or volatile
- attributes. */
- }
- }
- if (is_ref)
- val = value_ref (value_ind (val), refcode);
- type = value_type (val);
- type_print (type, "", stream, -1);
- gdb_printf (stream, ") ");
- }
- else
- {
- /* normal case */
- gdb_printf (stream, "(");
- type_print (value_type (val), "", stream, -1);
- gdb_printf (stream, ") ");
- }
- }
- if (!value_initialized (val))
- gdb_printf (stream, " [uninitialized] ");
- if (options->objectprint && (type->code () == TYPE_CODE_STRUCT))
- {
- /* Attempt to determine real type of object. */
- real_type = value_rtti_type (val, &full, &top, &using_enc);
- if (real_type)
- {
- /* We have RTTI information, so use it. */
- val = value_full_object (val, real_type,
- full, top, using_enc);
- /* In a destructor we might see a real type that is a
- superclass of the object's type. In this case it is
- better to leave the object as-is. */
- if (!(full
- && (TYPE_LENGTH (real_type)
- < TYPE_LENGTH (value_enclosing_type (val)))))
- val = value_cast (real_type, val);
- gdb_printf (stream, "(%s%s) ",
- real_type->name (),
- full ? "" : _(" [incomplete object]"));
- }
- else if (type != check_typedef (value_enclosing_type (val)))
- {
- /* No RTTI information, so let's do our best. */
- gdb_printf (stream, "(%s ?) ",
- value_enclosing_type (val)->name ());
- val = value_cast (value_enclosing_type (val), val);
- }
- }
- common_val_print (val, stream, 0, &opts, current_language);
- }
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