gcc/substring-locations.cc - gcc - Git at Google

 /* Source locations within string literals.
    Copyright (C) 2016-2023 Free Software Foundation, Inc.

 This file is part of GCC.

 GCC 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, or (at your option) any later
 version.

 GCC 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 GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */

 #include "config.h"
 #include "system.h"
 #include "coretypes.h"
 #include "intl.h"
 #include "diagnostic.h"
 #include "cpplib.h"
 #include "tree.h"
 #include "langhooks.h"
 #include "substring-locations.h"
 #include "gcc-rich-location.h"

 /* format_string_diagnostic_t's ctor, giving information for use by
    the emit_warning* member functions, as follows:

    They attempt to obtain precise location information within a string
    literal from FMT_LOC.

    Case 1: if substring location is available, and is within the range of
    the format string itself, the primary location of the
    diagnostic is the substring range obtained from FMT_LOC, with the
    caret at the *end* of the substring range.

    For example:

      test.c:90:10: warning: problem with '%i' here [-Wformat=]
      printf ("hello %i", msg);
                     ~^

    Case 2: if the substring location is available, but is not within
    the range of the format string, the primary location is that of the
    format string, and a note is emitted showing the substring location.

    For example:
      test.c:90:10: warning: problem with '%i' here [-Wformat=]
      printf("hello " INT_FMT " world", msg);
             ^~~~~~~~~~~~~~~~~~~~~~~~~
      test.c:19: note: format string is defined here
      #define INT_FMT "%i"
                       ~^

    Case 3: if precise substring information is unavailable, the primary
    location is that of the whole string passed to FMT_LOC's constructor.
    For example:

      test.c:90:10: warning: problem with '%i' here [-Wformat=]
      printf(fmt, msg);
             ^~~

    For each of cases 1-3, if param_loc is not UNKNOWN_LOCATION, then it is used
    as a secondary range within the warning.  For example, here it
    is used with case 1:

      test.c:90:16: warning: '%s' here but arg 2 has 'long' type [-Wformat=]
      printf ("foo %s bar", long_i + long_j);
                   ~^       ~~~~~~~~~~~~~~~

    and here with case 2:

      test.c:90:16: warning: '%s' here but arg 2 has 'long' type [-Wformat=]
      printf ("foo " STR_FMT " bar", long_i + long_j);
              ^~~~~~~~~~~~~~~~~~~~~  ~~~~~~~~~~~~~~~
      test.c:89:16: note: format string is defined here
      #define STR_FMT "%s"
                       ~^

    and with case 3:

      test.c:90:10: warning: '%i' here, but arg 2 is "const char *' [-Wformat=]
      printf(fmt, msg);
             ^~~  ~~~

    If non-NULL, then FMT_LABEL will be used to label the location within the
    string for cases 1 and 2; if non-NULL, then PARAM_LABEL will be used to label
    the parameter.  For example with case 1:

     test.c:90:16: warning: '%s' here but arg 2 has 'long' type [-Wformat=]
      printf ("foo %s bar", long_i + long_j);
                   ~^       ~~~~~~~~~~~~~~~
                                   |
                                   int

    and with case 2:

      test.c:90:10: warning: problem with '%i' here [-Wformat=]
      printf("hello " INT_FMT " world", msg);
             ^~~~~~~~~~~~~~~~~~~~~~~~~
      test.c:19: note: format string is defined here
      #define INT_FMT "%i"
                       ~^
                        |
                        int

    If CORRECTED_SUBSTRING is non-NULL, use it for cases 1 and 2 to provide
    a fix-it hint, suggesting that it should replace the text within the
    substring range.  For example:

      test.c:90:10: warning: problem with '%i' here [-Wformat=]
      printf ("hello %i", msg);
                     ~^
                     %s

 */

 format_string_diagnostic_t::
 format_string_diagnostic_t (const substring_loc &fmt_loc,
 			    const range_label *fmt_label,
 			    location_t param_loc,
 			    const range_label *param_label,
 			    const char *corrected_substring)
 : m_fmt_loc (fmt_loc),
   m_fmt_label (fmt_label),
   m_param_loc (param_loc),
   m_param_label (param_label),
   m_corrected_substring (corrected_substring)
 {
 }

 /* Emit a warning governed by option OPT, using SINGULAR_GMSGID as the
    format string (or if PLURAL_GMSGID is different from SINGULAR_GMSGID,
    using SINGULAR_GMSGID, PLURAL_GMSGID and N as arguments to ngettext)
    and AP as its arguments.

    Return true if a warning was emitted, false otherwise.  */

 bool
 format_string_diagnostic_t::emit_warning_n_va (int opt,
 					       unsigned HOST_WIDE_INT n,
 					       const char *singular_gmsgid,
 					       const char *plural_gmsgid,
 					       va_list *ap) const
 {
   bool substring_within_range = false;
   location_t primary_loc;
   location_t fmt_substring_loc = UNKNOWN_LOCATION;
   source_range fmt_loc_range
     = get_range_from_loc (line_table, m_fmt_loc.get_fmt_string_loc ());
   const char *err = m_fmt_loc.get_location (&fmt_substring_loc);
   source_range fmt_substring_range
     = get_range_from_loc (line_table, fmt_substring_loc);
   if (err)
     /* Case 3: unable to get substring location.  */
     primary_loc = m_fmt_loc.get_fmt_string_loc ();
   else
     {
       if (fmt_substring_range.m_start >= fmt_loc_range.m_start
 	  && fmt_substring_range.m_start <= fmt_loc_range.m_finish
 	  && fmt_substring_range.m_finish >= fmt_loc_range.m_start
 	  && fmt_substring_range.m_finish <= fmt_loc_range.m_finish)
 	/* Case 1.  */
 	{
 	  substring_within_range = true;
 	  primary_loc = fmt_substring_loc;
 	}
       else
 	/* Case 2.  */
 	{
 	  substring_within_range = false;
 	  primary_loc = m_fmt_loc.get_fmt_string_loc ();
 	}
     }

   /* Only use fmt_label in the initial warning for case 1.  */
   const range_label *primary_label = NULL;
   if (substring_within_range)
     primary_label = m_fmt_label;

   auto_diagnostic_group d;
   gcc_rich_location richloc (primary_loc, primary_label);

   if (m_param_loc != UNKNOWN_LOCATION)
     richloc.add_range (m_param_loc, SHOW_RANGE_WITHOUT_CARET, m_param_label);

   if (!err && m_corrected_substring && substring_within_range)
     richloc.add_fixit_replace (fmt_substring_range, m_corrected_substring);

   diagnostic_info diagnostic;
   if (singular_gmsgid != plural_gmsgid)
     {
       unsigned long gtn;

       if (sizeof n <= sizeof gtn)
 	gtn = n;
       else
 	/* Use the largest number ngettext can handle, otherwise
 	   preserve the six least significant decimal digits for
 	   languages where the plural form depends on them.  */
 	gtn = n <= ULONG_MAX ? n : n % 1000000LU + 1000000LU;

       const char *text = ngettext (singular_gmsgid, plural_gmsgid, gtn);
       diagnostic_set_info_translated (&diagnostic, text, ap, &richloc,
 				      DK_WARNING);
     }
   else
     diagnostic_set_info (&diagnostic, singular_gmsgid, ap, &richloc,
 			 DK_WARNING);
   diagnostic.option_index = opt;
   bool warned = diagnostic_report_diagnostic (global_dc, &diagnostic);

   if (!err && fmt_substring_loc && !substring_within_range)
     /* Case 2.  */
     if (warned)
       {
 	/* Use fmt_label in the note for case 2.  */
 	rich_location substring_richloc (line_table, fmt_substring_loc,
 					 m_fmt_label);
 	if (m_corrected_substring)
 	  substring_richloc.add_fixit_replace (fmt_substring_range,
 					       m_corrected_substring);
 	inform (&substring_richloc,
 		"format string is defined here");
       }

   return warned;
 }

 /* Singular-only version of the above.  */

 bool
 format_string_diagnostic_t::emit_warning_va (int opt, const char *gmsgid,
 					     va_list *ap) const
 {
   return emit_warning_n_va (opt, 0, gmsgid, gmsgid, ap);
 }

 /* Variadic version of the above (singular only).  */

 bool
 format_string_diagnostic_t::emit_warning (int opt, const char *gmsgid,
 					  ...) const
 {
   va_list ap;
   va_start (ap, gmsgid);
   bool warned = emit_warning_va (opt, gmsgid, &ap);
   va_end (ap);

   return warned;
 }

 /* Variadic version of the above (singular vs plural).  */

 bool
 format_string_diagnostic_t::emit_warning_n (int opt, unsigned HOST_WIDE_INT n,
 					    const char *singular_gmsgid,
 					    const char *plural_gmsgid,
 					    ...) const
 {
   va_list ap;
   va_start (ap, plural_gmsgid);
   bool warned = emit_warning_n_va (opt, n, singular_gmsgid, plural_gmsgid,
 				   &ap);
   va_end (ap);

   return warned;
 }

 /* Attempt to determine the source location of the substring.
    If successful, return NULL and write the source location to *OUT_LOC.
    Otherwise return an error message.  Error messages are intended
    for GCC developers (to help debugging) rather than for end-users.  */

 const char *
 substring_loc::get_location (location_t *out_loc) const
 {
   gcc_assert (out_loc);
   return lang_hooks.get_substring_location (*this, out_loc);
 }
	/* Source locations within string literals.
	Copyright (C) 2016-2023 Free Software Foundation, Inc.

	This file is part of GCC.

	GCC 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, or (at your option) any later
	version.

	GCC 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 GCC; see the file COPYING3. If not see
	<http://www.gnu.org/licenses/>. */

	#include "config.h"
	#include "system.h"
	#include "coretypes.h"
	#include "intl.h"
	#include "diagnostic.h"
	#include "cpplib.h"
	#include "tree.h"
	#include "langhooks.h"
	#include "substring-locations.h"
	#include "gcc-rich-location.h"

	/* format_string_diagnostic_t's ctor, giving information for use by
	the emit_warning* member functions, as follows:

	They attempt to obtain precise location information within a string
	literal from FMT_LOC.

	Case 1: if substring location is available, and is within the range of
	the format string itself, the primary location of the
	diagnostic is the substring range obtained from FMT_LOC, with the
	caret at the end of the substring range.

	For example:

	test.c:90:10: warning: problem with '%i' here [-Wformat=]
	printf ("hello %i", msg);
	~^

	Case 2: if the substring location is available, but is not within
	the range of the format string, the primary location is that of the
	format string, and a note is emitted showing the substring location.

	For example:
	test.c:90:10: warning: problem with '%i' here [-Wformat=]
	printf("hello " INT_FMT " world", msg);
	^~~~~~~~~~~~~~~~~~~~~~~~~
	test.c:19: note: format string is defined here
	#define INT_FMT "%i"
	~^

	Case 3: if precise substring information is unavailable, the primary
	location is that of the whole string passed to FMT_LOC's constructor.
	For example:

	test.c:90:10: warning: problem with '%i' here [-Wformat=]
	printf(fmt, msg);
	^~~

	For each of cases 1-3, if param_loc is not UNKNOWN_LOCATION, then it is used
	as a secondary range within the warning. For example, here it
	is used with case 1:

	test.c:90:16: warning: '%s' here but arg 2 has 'long' type [-Wformat=]
	printf ("foo %s bar", long_i + long_j);
	~^ ~~~~~~~~~~~~~~~

	and here with case 2:

	test.c:90:16: warning: '%s' here but arg 2 has 'long' type [-Wformat=]
	printf ("foo " STR_FMT " bar", long_i + long_j);
	^~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~
	test.c:89:16: note: format string is defined here
	#define STR_FMT "%s"
	~^

	and with case 3:

	test.c:90:10: warning: '%i' here, but arg 2 is "const char *' [-Wformat=]
	printf(fmt, msg);
	^~~ ~~~

	If non-NULL, then FMT_LABEL will be used to label the location within the
	string for cases 1 and 2; if non-NULL, then PARAM_LABEL will be used to label
	the parameter. For example with case 1:

	test.c:90:16: warning: '%s' here but arg 2 has 'long' type [-Wformat=]
	printf ("foo %s bar", long_i + long_j);
	~^ ~~~~~~~~~~~~~~~
	\|
	int

	and with case 2:

	test.c:90:10: warning: problem with '%i' here [-Wformat=]
	printf("hello " INT_FMT " world", msg);
	^~~~~~~~~~~~~~~~~~~~~~~~~
	test.c:19: note: format string is defined here
	#define INT_FMT "%i"
	~^
	\|
	int

	If CORRECTED_SUBSTRING is non-NULL, use it for cases 1 and 2 to provide
	a fix-it hint, suggesting that it should replace the text within the
	substring range. For example:

	test.c:90:10: warning: problem with '%i' here [-Wformat=]
	printf ("hello %i", msg);
	~^
	%s

	*/

	format_string_diagnostic_t::
	format_string_diagnostic_t (const substring_loc &fmt_loc,
	const range_label *fmt_label,
	location_t param_loc,
	const range_label *param_label,
	const char *corrected_substring)
	: m_fmt_loc (fmt_loc),
	m_fmt_label (fmt_label),
	m_param_loc (param_loc),
	m_param_label (param_label),
	m_corrected_substring (corrected_substring)
	{
	}

	/* Emit a warning governed by option OPT, using SINGULAR_GMSGID as the
	format string (or if PLURAL_GMSGID is different from SINGULAR_GMSGID,
	using SINGULAR_GMSGID, PLURAL_GMSGID and N as arguments to ngettext)
	and AP as its arguments.

	Return true if a warning was emitted, false otherwise. */

	bool
	format_string_diagnostic_t::emit_warning_n_va (int opt,
	unsigned HOST_WIDE_INT n,
	const char *singular_gmsgid,
	const char *plural_gmsgid,
	va_list *ap) const
	{
	bool substring_within_range = false;
	location_t primary_loc;
	location_t fmt_substring_loc = UNKNOWN_LOCATION;
	source_range fmt_loc_range
	= get_range_from_loc (line_table, m_fmt_loc.get_fmt_string_loc ());
	const char *err = m_fmt_loc.get_location (&fmt_substring_loc);
	source_range fmt_substring_range
	= get_range_from_loc (line_table, fmt_substring_loc);
	if (err)
	/* Case 3: unable to get substring location. */
	primary_loc = m_fmt_loc.get_fmt_string_loc ();
	else
	{
	if (fmt_substring_range.m_start >= fmt_loc_range.m_start
	&& fmt_substring_range.m_start <= fmt_loc_range.m_finish
	&& fmt_substring_range.m_finish >= fmt_loc_range.m_start
	&& fmt_substring_range.m_finish <= fmt_loc_range.m_finish)
	/* Case 1. */
	{
	substring_within_range = true;
	primary_loc = fmt_substring_loc;
	}
	else
	/* Case 2. */
	{
	substring_within_range = false;
	primary_loc = m_fmt_loc.get_fmt_string_loc ();
	}
	}

	/* Only use fmt_label in the initial warning for case 1. */
	const range_label *primary_label = NULL;
	if (substring_within_range)
	primary_label = m_fmt_label;

	auto_diagnostic_group d;
	gcc_rich_location richloc (primary_loc, primary_label);

	if (m_param_loc != UNKNOWN_LOCATION)
	richloc.add_range (m_param_loc, SHOW_RANGE_WITHOUT_CARET, m_param_label);

	if (!err && m_corrected_substring && substring_within_range)
	richloc.add_fixit_replace (fmt_substring_range, m_corrected_substring);

	diagnostic_info diagnostic;
	if (singular_gmsgid != plural_gmsgid)
	{
	unsigned long gtn;

	if (sizeof n <= sizeof gtn)
	gtn = n;
	else
	/* Use the largest number ngettext can handle, otherwise
	preserve the six least significant decimal digits for
	languages where the plural form depends on them. */
	gtn = n <= ULONG_MAX ? n : n % 1000000LU + 1000000LU;

	const char *text = ngettext (singular_gmsgid, plural_gmsgid, gtn);
	diagnostic_set_info_translated (&diagnostic, text, ap, &richloc,
	DK_WARNING);
	}
	else
	diagnostic_set_info (&diagnostic, singular_gmsgid, ap, &richloc,
	DK_WARNING);
	diagnostic.option_index = opt;
	bool warned = diagnostic_report_diagnostic (global_dc, &diagnostic);

	if (!err && fmt_substring_loc && !substring_within_range)
	/* Case 2. */
	if (warned)
	{
	/* Use fmt_label in the note for case 2. */
	rich_location substring_richloc (line_table, fmt_substring_loc,
	m_fmt_label);
	if (m_corrected_substring)
	substring_richloc.add_fixit_replace (fmt_substring_range,
	m_corrected_substring);
	inform (&substring_richloc,
	"format string is defined here");
	}

	return warned;
	}

	/* Singular-only version of the above. */

	bool
	format_string_diagnostic_t::emit_warning_va (int opt, const char *gmsgid,
	va_list *ap) const
	{
	return emit_warning_n_va (opt, 0, gmsgid, gmsgid, ap);
	}

	/* Variadic version of the above (singular only). */

	bool
	format_string_diagnostic_t::emit_warning (int opt, const char *gmsgid,
	...) const
	{
	va_list ap;
	va_start (ap, gmsgid);
	bool warned = emit_warning_va (opt, gmsgid, &ap);
	va_end (ap);

	return warned;
	}

	/* Variadic version of the above (singular vs plural). */

	bool
	format_string_diagnostic_t::emit_warning_n (int opt, unsigned HOST_WIDE_INT n,
	const char *singular_gmsgid,
	const char *plural_gmsgid,
	...) const
	{
	va_list ap;
	va_start (ap, plural_gmsgid);
	bool warned = emit_warning_n_va (opt, n, singular_gmsgid, plural_gmsgid,
	&ap);
	va_end (ap);

	return warned;
	}

	/* Attempt to determine the source location of the substring.
	If successful, return NULL and write the source location to *OUT_LOC.
	Otherwise return an error message. Error messages are intended
	for GCC developers (to help debugging) rather than for end-users. */

	const char *
	substring_loc::get_location (location_t *out_loc) const
	{
	gcc_assert (out_loc);
	return lang_hooks.get_substring_location (*this, out_loc);
	}