gcc/diagnostic-show-locus.c

   1 /* Diagnostic subroutines for printing source-code
   2    Copyright (C) 1999-2015 Free Software Foundation, Inc.
   3    Contributed by Gabriel Dos Reis <gdr@codesourcery.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "version.h"
  25 #include "demangle.h"
  26 #include "intl.h"
  27 #include "backtrace.h"
  28 #include "diagnostic.h"
  29 #include "diagnostic-color.h"
  30
  31 #ifdef HAVE_TERMIOS_H
  32 # include <termios.h>
  33 #endif
  34
  35 #ifdef GWINSZ_IN_SYS_IOCTL
  36 # include <sys/ioctl.h>
  37 #endif
  38
  39 /* If LINE is longer than MAX_WIDTH, and COLUMN is not smaller than
  40    MAX_WIDTH by some margin, then adjust the start of the line such
  41    that the COLUMN is smaller than MAX_WIDTH minus the margin.  The
  42    margin is either CARET_LINE_MARGIN characters or the difference
  43    between the column and the length of the line, whatever is smaller.
  44    The length of LINE is given by LINE_WIDTH.  */
  45 static const char *
  46 adjust_line (const char *line, int line_width,
  47              int max_width, int *column_p)
  48 {
  49   int right_margin = CARET_LINE_MARGIN;
  50   int column = *column_p;
  51
  52   gcc_checking_assert (line_width >= column);
  53   right_margin = MIN (line_width - column, right_margin);
  54   right_margin = max_width - right_margin;
  55   if (line_width >= max_width && column > right_margin)
  56     {
  57       line += column - right_margin;
  58       *column_p = right_margin;
  59     }
  60   return line;
  61 }
  62
  63 /* Print the physical source line corresponding to the location of
  64    this diagnostic, and a caret indicating the precise column.  This
  65    function only prints two caret characters if the two locations
  66    given by DIAGNOSTIC are on the same line according to
  67    diagnostic_same_line().  */
  68 void
  69 diagnostic_show_locus (diagnostic_context * context,
  70                        const diagnostic_info *diagnostic)
  71 {
  72   if (!context->show_caret
  73       || diagnostic_location (diagnostic, 0) <= BUILTINS_LOCATION
  74       || diagnostic_location (diagnostic, 0) == context->last_location)
  75     return;
  76
  77   context->last_location = diagnostic_location (diagnostic, 0);
  78   expanded_location s0 = diagnostic_expand_location (diagnostic, 0);
  79   expanded_location s1 = { };
  80   /* Zero-initialized. This is checked later by diagnostic_print_caret_line.  */
  81
  82   if (diagnostic_location (diagnostic, 1) > BUILTINS_LOCATION)
  83     s1 = diagnostic_expand_location (diagnostic, 1);
  84
  85   diagnostic_print_caret_line (context, s0, s1,
  86                                context->caret_chars[0],
  87                                context->caret_chars[1]);
  88 }
  89
  90 /* Print (part) of the source line given by xloc1 with caret1 pointing
  91    at the column.  If xloc2.column != 0 and it fits within the same
  92    line as xloc1 according to diagnostic_same_line (), then caret2 is
  93    printed at xloc2.colum.  Otherwise, the caller has to set up things
  94    to print a second caret line for xloc2.  */
  95 void
  96 diagnostic_print_caret_line (diagnostic_context * context,
  97                              expanded_location xloc1,
  98                              expanded_location xloc2,
  99                              char caret1, char caret2)
 100 {
 101   if (!diagnostic_same_line (context, xloc1, xloc2))
 102     /* This will mean ignore xloc2.  */
 103     xloc2.column = 0;
 104   else if (xloc1.column == xloc2.column)
 105     xloc2.column++;
 106
 107   int cmax = MAX (xloc1.column, xloc2.column);
 108   int line_width;
 109   const char *line = location_get_source_line (xloc1.file, xloc1.line,
 110                                                &line_width);
 111   if (line == NULL || cmax > line_width)
 112     return;
 113
 114   /* Center the interesting part of the source line to fit in
 115      max_width, and adjust all columns accordingly.  */
 116   int max_width = context->caret_max_width;
 117   int offset = (int) cmax;
 118   line = adjust_line (line, line_width, max_width, &offset);
 119   offset -= cmax;
 120   cmax += offset;
 121   xloc1.column += offset;
 122   if (xloc2.column)
 123     xloc2.column += offset;
 124
 125   /* Print the source line.  */
 126   pp_newline (context->printer);
 127   const char *saved_prefix = pp_get_prefix (context->printer);
 128   pp_set_prefix (context->printer, NULL);
 129   pp_space (context->printer);
 130   while (max_width > 0 && line_width > 0)
 131     {
 132       char c = *line == '\t' ? ' ' : *line;
 133       if (c == '\0')
 134         c = ' ';
 135       pp_character (context->printer, c);
 136       max_width--;
 137       line_width--;
 138       line++;
 139     }
 140   pp_newline (context->printer);
 141
 142   /* Print the caret under the line.  */
 143   const char *caret_cs, *caret_ce;
 144   caret_cs = colorize_start (pp_show_color (context->printer), "caret");
 145   caret_ce = colorize_stop (pp_show_color (context->printer));
 146   int cmin = xloc2.column
 147     ? MIN (xloc1.column, xloc2.column) : xloc1.column;
 148   int caret_min = cmin == xloc1.column ? caret1 : caret2;
 149   int caret_max = cmin == xloc1.column ? caret2 : caret1;
 150
 151   /* cmin is >= 1, but we indent with an extra space at the start like
 152      we did above.  */
 153   int i;
 154   for (i = 0; i < cmin; i++)
 155     pp_space (context->printer);
 156   pp_printf (context->printer, "%s%c%s", caret_cs, caret_min, caret_ce);
 157
 158   if (xloc2.column)
 159     {
 160       for (i++; i < cmax; i++)
 161         pp_space (context->printer);
 162       pp_printf (context->printer, "%s%c%s", caret_cs, caret_max, caret_ce);
 163     }
 164   pp_set_prefix (context->printer, saved_prefix);
 165   pp_needs_newline (context->printer) = true;
 166 }