/* Source locations within string literals. Copyright (C) 2016-2020 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 . */ #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); }