binutils-gdb/gdb/valprint.h
Kevin Buettner 2dc80cf8a5 Restrict use of minsym names when printing addresses in disassembled code
build_address_symbolic contains some code which causes it to
prefer the minsym over the the function symbol in certain cases.
The cases where this occurs are the same as the "certain pathological
cases" that used to exist in find_frame_funname().

This commit largely disables that code; it will only prefer the
minsym when the address of minsym is identical to that of the address
under consideration AND the function address for the symbtab sym is
not the same as the address under consideration.

So, without this change, when using the dw2-ranges-func-lo-cold
executable from the gdb.dwarf2/dw2-ranges-func.exp test, GDB exhibits
the following behavior:

(gdb) x/5i foo_cold
   0x40110d <foo+4294967277>:	push   %rbp
   0x40110e <foo+4294967278>:	mov    %rsp,%rbp
   0x401111 <foo+4294967281>:	callq  0x401106 <baz>
   0x401116 <foo+4294967286>:	nop
   0x401117 <foo+4294967287>:	pop    %rbp

On the other hand, still without this change, using the
dw2-ranges-func-hi-cold executable from the same test, GDB
does this instead:

(gdb) x/5i foo_cold
   0x401128 <foo_cold>:	push   %rbp
   0x401129 <foo_cold+1>:	mov    %rsp,%rbp
   0x40112c <foo_cold+4>:	callq  0x401134 <baz>
   0x401131 <foo_cold+9>:	nop
   0x401132 <foo_cold+10>:	pop    %rbp

This is inconsistent behavior.  When foo_cold is at a lower
address than the function's entry point, the symtab symbol (foo)
is displayed along with a large positive offset which would wrap
around the address space if the address space were only 32 bits wide.
(A later patch fixes this problem by displaying negative offsets.)

This commit makes the behavior uniform for both the "lo-cold" and
"hi-cold" cases:

lo-cold:

(gdb) x/5i foo_cold
   0x40110d <foo_cold>:	push   %rbp
   0x40110e <foo-18>:	mov    %rsp,%rbp
   0x401111 <foo-15>:	callq  0x401106 <baz>
   0x401116 <foo-10>:	nop
   0x401117 <foo-9>:	pop    %rbp

hi-cold:

(gdb) x/5i foo_cold
   0x401128 <foo_cold>:	push   %rbp
   0x401129 <foo+35>:	mov    %rsp,%rbp
   0x40112c <foo+38>:	callq  0x401134 <baz>
   0x401131 <foo+43>:	nop
   0x401132 <foo+44>:	pop    %rbp

In both cases, the symbol shown for the address at which foo_cold
resides is shown as <foo_cold>.  Subsequent offsets are shown as
either negative or positive offsets from the entry pc for foo.

When disassembling a function, care must be taken to NOT display
<+0> as the offset for the second range.  For this reason, I found
it necessary to add the "prefer_sym_over_minsym" parameter to
build_address_symbolic.  The type of this flag is a bool; do_demangle
ought to be a bool also, so I made this change at the same time.

gdb/ChangeLog:

	* valprint.h (build_address_symbolic): Add "prefer_sym_over_minsym"
	parameter.  Change type of "do_demangle" to bool.
	* disasm.c (gdb_pretty_print_disassembler::pretty_print_insn):
	Pass suitable "prefer_sym_over_minsym" flag to
	build_address_symbolic().  Don't output "+" for negative offsets.
	* printcmd.c (print_address_symbolic): Update invocation of
	build_address_symbolic to include a "prefer_sym_over_minsym"
	flag.
	(build_address_symbolic): Add "prefer_sym_over_minsym" parameter.
	Restrict cases in which use of minimal symbol is preferred to that
	of a found symbol.  Update comments.
2019-07-27 13:28:56 -07:00

286 lines
9.4 KiB
C++

/* Declarations for value printing routines for GDB, the GNU debugger.
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/>. */
#ifndef VALPRINT_H
#define VALPRINT_H
#include "cli/cli-option.h"
/* This is used to pass formatting options to various value-printing
functions. */
struct value_print_options
{
/* Pretty-formatting control. */
enum val_prettyformat prettyformat;
/* Controls pretty formatting of arrays. */
int prettyformat_arrays;
/* Controls pretty formatting of structures. */
int prettyformat_structs;
/* Controls printing of virtual tables. */
int vtblprint;
/* Controls printing of nested unions. */
int unionprint;
/* Controls printing of addresses. */
int addressprint;
/* Controls looking up an object's derived type using what we find
in its vtables. */
int objectprint;
/* Maximum number of chars to print for a string pointer value or vector
contents, or UINT_MAX for no limit. Note that "set print elements 0"
stores UINT_MAX in print_max, which displays in a show command as
"unlimited". */
unsigned int print_max;
/* Print repeat counts if there are more than this many repetitions
of an element in an array. */
unsigned int repeat_count_threshold;
/* The global output format letter. */
int output_format;
/* The current format letter. This is set locally for a given call,
e.g. when the user passes a format to "print". */
int format;
/* Stop printing at null character? */
int stop_print_at_null;
/* True if we should print the index of each element when printing
an array. */
int print_array_indexes;
/* If nonzero, then dereference references, otherwise just print
them like pointers. */
int deref_ref;
/* If nonzero, print static fields. */
int static_field_print;
/* If nonzero, print static fields for Pascal. FIXME: C++ has a
flag, why not share with Pascal too? */
int pascal_static_field_print;
/* If non-zero don't do Python pretty-printing. */
int raw;
/* If nonzero, print the value in "summary" form.
If raw and summary are both non-zero, don't print non-scalar values
("..." is printed instead). */
int summary;
/* If nonzero, when printing a pointer, print the symbol to which it
points, if any. */
int symbol_print;
/* Maximum print depth when printing nested aggregates. */
int max_depth;
/* Whether "finish" should print the value. */
int finish_print;
};
/* Create an option_def_group for the value_print options, with OPTS
as context. */
extern gdb::option::option_def_group make_value_print_options_def_group
(value_print_options *opts);
/* The global print options set by the user. In general this should
not be directly accessed, except by set/show commands. Ordinary
code should call get_user_print_options instead. */
extern struct value_print_options user_print_options;
/* Initialize *OPTS to be a copy of the user print options. */
extern void get_user_print_options (struct value_print_options *opts);
/* Initialize *OPTS to be a copy of the user print options, but with
pretty-formatting disabled. */
extern void get_no_prettyformat_print_options (struct value_print_options *);
/* Initialize *OPTS to be a copy of the user print options, but using
FORMAT as the formatting option. */
extern void get_formatted_print_options (struct value_print_options *opts,
char format);
extern void maybe_print_array_index (struct type *index_type, LONGEST index,
struct ui_file *stream,
const struct value_print_options *);
extern void val_print_array_elements (struct type *, LONGEST,
CORE_ADDR, struct ui_file *, int,
struct value *,
const struct value_print_options *,
unsigned int);
extern void val_print_scalar_formatted (struct type *,
LONGEST,
struct value *,
const struct value_print_options *,
int,
struct ui_file *);
extern void print_binary_chars (struct ui_file *, const gdb_byte *,
unsigned int, enum bfd_endian, bool);
extern void print_octal_chars (struct ui_file *, const gdb_byte *,
unsigned int, enum bfd_endian);
extern void print_decimal_chars (struct ui_file *, const gdb_byte *,
unsigned int, bool, enum bfd_endian);
extern void print_hex_chars (struct ui_file *, const gdb_byte *,
unsigned int, enum bfd_endian, bool);
extern void print_char_chars (struct ui_file *, struct type *,
const gdb_byte *, unsigned int, enum bfd_endian);
extern void print_function_pointer_address (const struct value_print_options *options,
struct gdbarch *gdbarch,
CORE_ADDR address,
struct ui_file *stream);
extern int read_string (CORE_ADDR addr, int len, int width,
unsigned int fetchlimit,
enum bfd_endian byte_order,
gdb::unique_xmalloc_ptr<gdb_byte> *buffer,
int *bytes_read);
extern void val_print_optimized_out (const struct value *val,
struct ui_file *stream);
/* Prints "<not saved>" to STREAM. */
extern void val_print_not_saved (struct ui_file *stream);
extern void val_print_unavailable (struct ui_file *stream);
extern void val_print_invalid_address (struct ui_file *stream);
/* An instance of this is passed to generic_val_print and describes
some language-specific ways to print things. */
struct generic_val_print_decorations
{
/* Printing complex numbers: what to print before, between the
elements, and after. */
const char *complex_prefix;
const char *complex_infix;
const char *complex_suffix;
/* Boolean true and false. */
const char *true_name;
const char *false_name;
/* What to print when we see TYPE_CODE_VOID. */
const char *void_name;
/* Array start and end strings. */
const char *array_start;
const char *array_end;
};
extern void generic_val_print (struct type *type,
int embedded_offset, CORE_ADDR address,
struct ui_file *stream, int recurse,
struct value *original_value,
const struct value_print_options *options,
const struct generic_val_print_decorations *);
extern void generic_emit_char (int c, struct type *type, struct ui_file *stream,
int quoter, const char *encoding);
extern void generic_printstr (struct ui_file *stream, struct type *type,
const gdb_byte *string, unsigned int length,
const char *encoding, int force_ellipses,
int quote_char, int c_style_terminator,
const struct value_print_options *options);
/* Run the "output" command. ARGS and FROM_TTY are the usual
arguments passed to all command implementations, except ARGS is
const. */
extern void output_command (const char *args, int from_tty);
extern int val_print_scalar_type_p (struct type *type);
struct format_data
{
int count;
char format;
char size;
/* True if the value should be printed raw -- that is, bypassing
python-based formatters. */
unsigned char raw;
};
extern void print_command_parse_format (const char **expp, const char *cmdname,
value_print_options *opts);
/* Print VAL to console according to OPTS, including recording it to
the history. */
extern void print_value (value *val, const value_print_options &opts);
/* Completer for the "print", "call", and "compile print"
commands. */
extern void print_command_completer (struct cmd_list_element *ignore,
completion_tracker &tracker,
const char *text, const char *word);
/* Given an address ADDR return all the elements needed to print the
address in a symbolic form. NAME can be mangled or not depending
on DO_DEMANGLE (and also on the asm_demangle global variable,
manipulated via ''set print asm-demangle''). When
PREFER_SYM_OVER_MINSYM is true, names (and offsets) from minimal
symbols won't be used except in instances where no symbol was
found; otherwise, a minsym might be used in some instances (mostly
involving function with non-contiguous address ranges). Return
0 in case of success, when all the info in the OUT paramters is
valid. Return 1 otherwise. */
extern int build_address_symbolic (struct gdbarch *,
CORE_ADDR addr,
bool do_demangle,
bool prefer_sym_over_minsym,
std::string *name,
int *offset,
std::string *filename,
int *line,
int *unmapped);
/* Check to see if RECURSE is greater than or equal to the allowed
printing max-depth (see 'set print max-depth'). If it is then print an
ellipsis expression to STREAM and return true, otherwise return false.
LANGUAGE determines what type of ellipsis expression is printed. */
extern bool val_print_check_max_depth (struct ui_file *stream, int recurse,
const struct value_print_options *opts,
const struct language_defn *language);
#endif