gcc/tree-diagnostic.c

   1 /* Language-independent diagnostic subroutines for the GNU Compiler
   2    Collection that are only for use in the compilers proper and not
   3    the driver or other programs.
   4    Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
   5    2009, 2010 Free Software Foundation, Inc.
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify it under
  10 the terms of the GNU General Public License as published by the Free
  11 Software Foundation; either version 3, or (at your option) any later
  12 version.
  13
  14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17 for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "tree.h"
  27 #include "diagnostic.h"
  28 #include "tree-pretty-print.h"
  29 #include "tree-diagnostic.h"
  30 #include "dumpfile.h" /* TDF_DIAGNOSTIC */
  31 #include "langhooks.h"
  32 #include "langhooks-def.h"
  33 #include "vec.h"
  34 #include "intl.h"
  35
  36 /* Prints out, if necessary, the name of the current function
  37    that caused an error.  Called from all error and warning functions.  */
  38 void
  39 diagnostic_report_current_function (diagnostic_context *context,
  40                                     diagnostic_info *diagnostic)
  41 {
  42   diagnostic_report_current_module (context, diagnostic->location);
  43   lang_hooks.print_error_function (context, input_filename, diagnostic);
  44 }
  45
  46 static void
  47 default_tree_diagnostic_starter (diagnostic_context *context,
  48                                  diagnostic_info *diagnostic)
  49 {
  50   diagnostic_report_current_function (context, diagnostic);
  51   pp_set_prefix (context->printer, diagnostic_build_prefix (context,
  52                                                             diagnostic));
  53 }
  54
  55 /* This is a pair made of a location and the line map it originated
  56    from.  It's used in the maybe_unwind_expanded_macro_loc function
  57    below.  */
  58 typedef struct
  59 {
  60   const struct line_map *map;
  61   source_location where;
  62 } loc_map_pair;
  63
  64 DEF_VEC_O (loc_map_pair);
  65 DEF_VEC_ALLOC_O (loc_map_pair, heap);
  66
  67 /* Unwind the different macro expansions that lead to the token which
  68    location is WHERE and emit diagnostics showing the resulting
  69    unwound macro expansion trace.  Let's look at an example to see how
  70    the trace looks like.  Suppose we have this piece of code,
  71    artificially annotated with the line numbers to increase
  72    legibility:
  73
  74     $ cat -n test.c
  75       1    #define OPERATE(OPRD1, OPRT, OPRD2) \
  76       2      OPRD1 OPRT OPRD2;
  77       3
  78       4    #define SHIFTL(A,B) \
  79       5      OPERATE (A,<<,B)
  80       6
  81       7    #define MULT(A) \
  82       8      SHIFTL (A,1)
  83       9
  84      10    void
  85      11    g ()
  86      12    {
  87      13      MULT (1.0);// 1.0 << 1; <-- so this is an error.
  88      14    }
  89
  90    Here is the diagnostic that we want the compiler to generate:
  91
  92     test.c: In function ‘g’:
  93     test.c:5:14: error: invalid operands to binary << (have ‘double’ and ‘int’)
  94     test.c:2:9: note: in definition of macro 'OPERATE'
  95     test.c:8:3: note: in expansion of macro 'SHIFTL'
  96     test.c:13:3: note: in expansion of macro 'MULT'
  97
  98    The part that goes from the third to the fifth line of this
  99    diagnostic (the lines containing the 'note:' string) is called the
 100    unwound macro expansion trace.  That's the part generated by this
 101    function.  */
 102
 103 static void
 104 maybe_unwind_expanded_macro_loc (diagnostic_context *context,
 105                                  diagnostic_info *diagnostic,
 106                                  source_location where)
 107 {
 108   const struct line_map *map;
 109   VEC(loc_map_pair,heap) *loc_vec = NULL;
 110   unsigned ix;
 111   loc_map_pair loc, *iter;
 112
 113   map = linemap_lookup (line_table, where);
 114   if (!linemap_macro_expansion_map_p (map))
 115     return;
 116
 117   /* Let's unwind the macros that got expanded and led to the token
 118      which location is WHERE.  We are going to store these macros into
 119      LOC_VEC, so that we can later walk it at our convenience to
 120      display a somewhat meaningful trace of the macro expansion
 121      history to the user.  Note that the first macro of the trace
 122      (which is OPERATE in the example above) is going to be stored at
 123      the beginning of LOC_VEC.  */
 124
 125   do
 126     {
 127       loc.where = where;
 128       loc.map = map;
 129
 130       VEC_safe_push (loc_map_pair, heap, loc_vec, loc);
 131
 132       /* WHERE is the location of a token inside the expansion of a
 133          macro.  MAP is the map holding the locations of that macro
 134          expansion.  Let's get the location of the token inside the
 135          context that triggered the expansion of this macro.
 136          This is basically how we go "down" in the trace of macro
 137          expansions that led to WHERE.  */
 138       where = linemap_unwind_toward_expansion (line_table, where, &map);
 139     } while (linemap_macro_expansion_map_p (map));
 140
 141   /* Now map is set to the map of the location in the source that
 142      first triggered the macro expansion.  This must be an ordinary map.  */
 143
 144   /* Walk LOC_VEC and print the macro expansion trace, unless the
 145      first macro which expansion triggered this trace was expanded
 146      inside a system header.  */
 147   if (!LINEMAP_SYSP (map))
 148     FOR_EACH_VEC_ELT (loc_map_pair, loc_vec, ix, iter)
 149       {
 150         source_location resolved_def_loc = 0, resolved_exp_loc = 0,
 151           saved_location = 0;
 152         int resolved_def_loc_line = 0, saved_location_line = 0;
 153         diagnostic_t saved_kind;
 154         const char *saved_prefix;
 155         /* Sometimes, in the unwound macro expansion trace, we want to
 156            print a part of the context that shows where, in the
 157            definition of the relevant macro, is the token (we are
 158            looking at) used.  That is the case in the introductory
 159            comment of this function, where we print:
 160
 161                test.c:2:9: note: in definition of macro 'OPERATE'.
 162
 163            We print that "macro definition context" because the
 164            diagnostic line (emitted by the call to
 165            pp_ouput_formatted_text in diagnostic_report_diagnostic):
 166
 167                test.c:5:14: error: invalid operands to binary << (have ‘double’ and ‘int’)
 168
 169            does not point into the definition of the macro where the
 170            token '<<' (that is an argument to the function-like macro
 171            OPERATE) is used.  So we must "display" the line of that
 172            macro definition context to the user somehow.
 173
 174            A contrario, when the first interesting diagnostic line
 175            points into the definition of the macro, we don't need to
 176            display any line for that macro definition in the trace
 177            anymore, otherwise it'd be redundant.
 178
 179            This flag is true when we need to display the context of
 180            the macro definition.  */
 181         bool print_definition_context_p = false;
 182
 183         /* Okay, now here is what we want.  For each token resulting
 184            from macro expansion we want to show: 1/ where in the
 185            definition of the macro the token comes from; 2/ where the
 186            macro got expanded.  */
 187
 188         /* Resolve the location iter->where into the locus 1/ of the
 189            comment above.  */
 190         resolved_def_loc =
 191           linemap_resolve_location (line_table, iter->where,
 192                                     LRK_MACRO_DEFINITION_LOCATION, NULL);
 193
 194         /* Don't print trace for locations that are reserved or from
 195            within a system header.  */
 196         {
 197           const struct line_map *m = NULL;
 198           source_location l = linemap_resolve_location (line_table, resolved_def_loc,
 199                                                         LRK_SPELLING_LOCATION,
 200                                                         &m);
 201           if (l < RESERVED_LOCATION_COUNT
 202               || LINEMAP_SYSP (m))
 203             continue;
 204
 205           resolved_def_loc_line = SOURCE_LINE (m, l);
 206         }
 207
 208         /* Resolve the location of the expansion point of the macro
 209            which expansion gave the token represented by def_loc.
 210            This is the locus 2/ of the earlier comment.  */
 211         resolved_exp_loc =
 212           linemap_resolve_location (line_table,
 213                                     MACRO_MAP_EXPANSION_POINT_LOCATION (iter->map),
 214                                     LRK_MACRO_DEFINITION_LOCATION, NULL);
 215
 216         saved_kind = diagnostic->kind;
 217         saved_prefix = pp_get_prefix (context->printer);
 218         saved_location = diagnostic->location;
 219         saved_location_line =
 220           expand_location_to_spelling_point (saved_location).line;
 221
 222         diagnostic->kind = DK_NOTE;
 223
 224         /* We need to print the context of the macro definition only
 225            when the locus of the first displayed diagnostic (displayed
 226            before this trace) was inside the definition of the
 227            macro.  */
 228         print_definition_context_p =
 229           (ix == 0 && (saved_location_line != resolved_def_loc_line));
 230
 231         if (print_definition_context_p)
 232           {
 233             diagnostic->location = resolved_def_loc;
 234             pp_set_prefix (context->printer,
 235                            diagnostic_build_prefix (context, diagnostic));
 236             pp_newline (context->printer);
 237             pp_printf (context->printer, "in definition of macro '%s'",
 238                        linemap_map_get_macro_name (iter->map));
 239             pp_destroy_prefix (context->printer);
 240             diagnostic_show_locus (context, diagnostic);
 241             /* At this step, as we've printed the context of the macro
 242                definition, we don't want to print the context of its
 243                expansion, otherwise, it'd be redundant.  */
 244             continue;
 245           }
 246
 247         diagnostic->location = resolved_exp_loc;
 248         pp_set_prefix (context->printer,
 249                        diagnostic_build_prefix (context, diagnostic));
 250         pp_newline (context->printer);
 251         pp_printf (context->printer, "in expansion of macro '%s'",
 252                    linemap_map_get_macro_name (iter->map));
 253         pp_destroy_prefix (context->printer);
 254         diagnostic_show_locus (context, diagnostic);
 255
 256         diagnostic->kind = saved_kind;
 257         diagnostic->location = saved_location;
 258         pp_set_prefix (context->printer, saved_prefix);
 259       }
 260
 261   VEC_free (loc_map_pair, heap, loc_vec);
 262 }
 263
 264 /*  This is a diagnostic finalizer implementation that is aware of
 265     virtual locations produced by libcpp.
 266
 267     It has to be called by the diagnostic finalizer of front ends that
 268     uses libcpp and wish to get diagnostics involving tokens resulting
 269     from macro expansion.
 270
 271     For a given location, if said location belongs to a token
 272     resulting from a macro expansion, this starter prints the context
 273     of the token.  E.g, for multiply nested macro expansion, it
 274     unwinds the nested macro expansions and prints them in a manner
 275     that is similar to what is done for function call stacks, or
 276     template instantiation contexts.  */
 277 void
 278 virt_loc_aware_diagnostic_finalizer (diagnostic_context *context,
 279                                      diagnostic_info *diagnostic)
 280 {
 281   maybe_unwind_expanded_macro_loc (context, diagnostic,
 282                                    diagnostic->location);
 283 }
 284
 285 /* Default tree printer.   Handles declarations only.  */
 286 static bool
 287 default_tree_printer (pretty_printer *pp, text_info *text, const char *spec,
 288                       int precision, bool wide, bool set_locus, bool hash)
 289 {
 290   tree t;
 291
 292   /* FUTURE: %+x should set the locus.  */
 293   if (precision != 0 || wide || hash)
 294     return false;
 295
 296   switch (*spec)
 297     {
 298     case 'E':
 299       t = va_arg (*text->args_ptr, tree);
 300       if (TREE_CODE (t) == IDENTIFIER_NODE)
 301         {
 302           pp_identifier (pp, IDENTIFIER_POINTER (t));
 303           return true;
 304         }
 305       break;
 306
 307     case 'D':
 308       t = va_arg (*text->args_ptr, tree);
 309       if (DECL_DEBUG_EXPR_IS_FROM (t) && DECL_DEBUG_EXPR (t))
 310         t = DECL_DEBUG_EXPR (t);
 311       break;
 312
 313     case 'F':
 314     case 'T':
 315       t = va_arg (*text->args_ptr, tree);
 316       break;
 317
 318     case 'K':
 319       percent_K_format (text);
 320       return true;
 321
 322     default:
 323       return false;
 324     }
 325
 326   if (set_locus && text->locus)
 327     *text->locus = DECL_SOURCE_LOCATION (t);
 328
 329   if (DECL_P (t))
 330     {
 331       const char *n = DECL_NAME (t)
 332         ? identifier_to_locale (lang_hooks.decl_printable_name (t, 2))
 333         : _("<anonymous>");
 334       pp_string (pp, n);
 335     }
 336   else
 337     dump_generic_node (pp, t, 0, TDF_DIAGNOSTIC, 0);
 338
 339   return true;
 340 }
 341
 342 /* Sets CONTEXT to use language independent diagnostics.  */
 343 void
 344 tree_diagnostics_defaults (diagnostic_context *context)
 345 {
 346   diagnostic_starter (context) = default_tree_diagnostic_starter;
 347   diagnostic_finalizer (context) = default_diagnostic_finalizer;
 348   diagnostic_format_decoder (context) = default_tree_printer;
 349 }