gcc/tree-diagnostic.cc

   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) 1999-2022 Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tree.h"
  26 #include "diagnostic.h"
  27 #include "tree-pretty-print.h"
  28 #include "gimple-pretty-print.h"
  29 #include "tree-diagnostic.h"
  30 #include "diagnostic-client-data-hooks.h"
  31 #include "langhooks.h"
  32 #include "intl.h"
  33
  34 /* Prints out, if necessary, the name of the current function
  35    that caused an error.  Called from all error and warning functions.  */
  36 void
  37 diagnostic_report_current_function (diagnostic_context *context,
  38                                     diagnostic_info *diagnostic)
  39 {
  40   location_t loc = diagnostic_location (diagnostic);
  41   diagnostic_report_current_module (context, loc);
  42   lang_hooks.print_error_function (context, LOCATION_FILE (loc), diagnostic);
  43 }
  44
  45 static void
  46 default_tree_diagnostic_starter (diagnostic_context *context,
  47                                  diagnostic_info *diagnostic)
  48 {
  49   diagnostic_report_current_function (context, diagnostic);
  50   pp_set_prefix (context->printer, diagnostic_build_prefix (context,
  51                                                             diagnostic));
  52 }
  53
  54 /* This is a pair made of a location and the line map it originated
  55    from.  It's used in the maybe_unwind_expanded_macro_loc function
  56    below.  */
  57 struct loc_map_pair
  58 {
  59   const line_map_macro *map;
  60   location_t where;
  61 };
  62
  63
  64 /* Unwind the different macro expansions that lead to the token which
  65    location is WHERE and emit diagnostics showing the resulting
  66    unwound macro expansion trace.  Let's look at an example to see how
  67    the trace looks like.  Suppose we have this piece of code,
  68    artificially annotated with the line numbers to increase
  69    legibility:
  70
  71     $ cat -n test.c
  72       1    #define OPERATE(OPRD1, OPRT, OPRD2) \
  73       2      OPRD1 OPRT OPRD2;
  74       3
  75       4    #define SHIFTL(A,B) \
  76       5      OPERATE (A,<<,B)
  77       6
  78       7    #define MULT(A) \
  79       8      SHIFTL (A,1)
  80       9
  81      10    void
  82      11    g ()
  83      12    {
  84      13      MULT (1.0);// 1.0 << 1; <-- so this is an error.
  85      14    }
  86
  87    Here is the diagnostic that we want the compiler to generate:
  88
  89     test.c: In function ‘g’:
  90     test.c:5:14: error: invalid operands to binary << (have ‘double’ and ‘int’)
  91     test.c:2:9: note: in definition of macro 'OPERATE'
  92     test.c:8:3: note: in expansion of macro 'SHIFTL'
  93     test.c:13:3: note: in expansion of macro 'MULT'
  94
  95    The part that goes from the third to the fifth line of this
  96    diagnostic (the lines containing the 'note:' string) is called the
  97    unwound macro expansion trace.  That's the part generated by this
  98    function.  */
  99
 100 void
 101 maybe_unwind_expanded_macro_loc (diagnostic_context *context,
 102                                  location_t where)
 103 {
 104   const struct line_map *map;
 105   auto_vec<loc_map_pair> loc_vec;
 106   unsigned ix;
 107   loc_map_pair loc, *iter;
 108
 109   const location_t original_loc = where;
 110
 111   map = linemap_lookup (line_table, where);
 112   if (!linemap_macro_expansion_map_p (map))
 113     return;
 114
 115   /* Let's unwind the macros that got expanded and led to the token
 116      which location is WHERE.  We are going to store these macros into
 117      LOC_VEC, so that we can later walk it at our convenience to
 118      display a somewhat meaningful trace of the macro expansion
 119      history to the user.  Note that the first macro of the trace
 120      (which is OPERATE in the example above) is going to be stored at
 121      the beginning of LOC_VEC.  */
 122
 123   do
 124     {
 125       loc.where = where;
 126       loc.map = linemap_check_macro (map);
 127
 128       loc_vec.safe_push (loc);
 129
 130       /* WHERE is the location of a token inside the expansion of a
 131          macro.  MAP is the map holding the locations of that macro
 132          expansion.  Let's get the location of the token inside the
 133          context that triggered the expansion of this macro.
 134          This is basically how we go "down" in the trace of macro
 135          expansions that led to WHERE.  */
 136       where = linemap_unwind_toward_expansion (line_table, where, &map);
 137     } while (linemap_macro_expansion_map_p (map));
 138
 139   /* Now map is set to the map of the location in the source that
 140      first triggered the macro expansion.  This must be an ordinary map.  */
 141   const line_map_ordinary *ord_map = linemap_check_ordinary (map);
 142
 143   /* Walk LOC_VEC and print the macro expansion trace, unless the
 144      first macro which expansion triggered this trace was expanded
 145      inside a system header.  */
 146   int saved_location_line =
 147     expand_location_to_spelling_point (original_loc).line;
 148
 149   if (!LINEMAP_SYSP (ord_map))
 150     FOR_EACH_VEC_ELT (loc_vec, ix, iter)
 151       {
 152         /* Sometimes, in the unwound macro expansion trace, we want to
 153            print a part of the context that shows where, in the
 154            definition of the relevant macro, is the token (we are
 155            looking at) used.  That is the case in the introductory
 156            comment of this function, where we print:
 157
 158                test.c:2:9: note: in definition of macro 'OPERATE'.
 159
 160            We print that "macro definition context" because the
 161            diagnostic line (emitted by the call to
 162            pp_ouput_formatted_text in diagnostic_report_diagnostic):
 163
 164                test.c:5:14: error: invalid operands to binary << (have ‘double’ and ‘int’)
 165
 166            does not point into the definition of the macro where the
 167            token '<<' (that is an argument to the function-like macro
 168            OPERATE) is used.  So we must "display" the line of that
 169            macro definition context to the user somehow.
 170
 171            A contrario, when the first interesting diagnostic line
 172            points into the definition of the macro, we don't need to
 173            display any line for that macro definition in the trace
 174            anymore, otherwise it'd be redundant.  */
 175
 176         /* Okay, now here is what we want.  For each token resulting
 177            from macro expansion we want to show: 1/ where in the
 178            definition of the macro the token comes from; 2/ where the
 179            macro got expanded.  */
 180
 181         /* Resolve the location iter->where into the locus 1/ of the
 182            comment above.  */
 183         location_t resolved_def_loc =
 184           linemap_resolve_location (line_table, iter->where,
 185                                     LRK_MACRO_DEFINITION_LOCATION, NULL);
 186
 187         /* Don't print trace for locations that are reserved or from
 188            within a system header.  */
 189         const line_map_ordinary *m = NULL;
 190         location_t l =
 191           linemap_resolve_location (line_table, resolved_def_loc,
 192                                     LRK_SPELLING_LOCATION,  &m);
 193         if (l < RESERVED_LOCATION_COUNT || LINEMAP_SYSP (m))
 194           continue;
 195
 196         /* We need to print the context of the macro definition only
 197            when the locus of the first displayed diagnostic (displayed
 198            before this trace) was inside the definition of the
 199            macro.  */
 200         int resolved_def_loc_line = SOURCE_LINE (m, l);
 201         if (ix == 0 && saved_location_line != resolved_def_loc_line)
 202           {
 203             diagnostic_append_note (context, resolved_def_loc,
 204                                     "in definition of macro %qs",
 205                                     linemap_map_get_macro_name (iter->map));
 206             /* At this step, as we've printed the context of the macro
 207                definition, we don't want to print the context of its
 208                expansion, otherwise, it'd be redundant.  */
 209             continue;
 210           }
 211
 212         /* Resolve the location of the expansion point of the macro
 213            which expansion gave the token represented by def_loc.
 214            This is the locus 2/ of the earlier comment.  */
 215         location_t resolved_exp_loc =
 216           linemap_resolve_location (line_table,
 217                                     MACRO_MAP_EXPANSION_POINT_LOCATION (iter->map),
 218                                     LRK_MACRO_DEFINITION_LOCATION, NULL);
 219
 220         diagnostic_append_note (context, resolved_exp_loc,
 221                                 "in expansion of macro %qs",
 222                                 linemap_map_get_macro_name (iter->map));
 223       }
 224 }
 225
 226 /*  This is a diagnostic finalizer implementation that is aware of
 227     virtual locations produced by libcpp.
 228
 229     It has to be called by the diagnostic finalizer of front ends that
 230     uses libcpp and wish to get diagnostics involving tokens resulting
 231     from macro expansion.
 232
 233     For a given location, if said location belongs to a token
 234     resulting from a macro expansion, this starter prints the context
 235     of the token.  E.g, for multiply nested macro expansion, it
 236     unwinds the nested macro expansions and prints them in a manner
 237     that is similar to what is done for function call stacks, or
 238     template instantiation contexts.  */
 239 void
 240 virt_loc_aware_diagnostic_finalizer (diagnostic_context *context,
 241                                      diagnostic_info *diagnostic)
 242 {
 243   maybe_unwind_expanded_macro_loc (context, diagnostic_location (diagnostic));
 244 }
 245
 246 /* Default tree printer.   Handles declarations only.  */
 247 bool
 248 default_tree_printer (pretty_printer *pp, text_info *text, const char *spec,
 249                       int precision, bool wide, bool set_locus, bool hash,
 250                       bool *, const char **)
 251 {
 252   tree t;
 253
 254   /* FUTURE: %+x should set the locus.  */
 255   if (precision != 0 || wide || hash)
 256     return false;
 257
 258   switch (*spec)
 259     {
 260     case 'E':
 261       t = va_arg (*text->args_ptr, tree);
 262       if (TREE_CODE (t) == IDENTIFIER_NODE)
 263         {
 264           pp_identifier (pp, IDENTIFIER_POINTER (t));
 265           return true;
 266         }
 267       break;
 268
 269     case 'D':
 270       t = va_arg (*text->args_ptr, tree);
 271       if (VAR_P (t) && DECL_HAS_DEBUG_EXPR_P (t))
 272         t = DECL_DEBUG_EXPR (t);
 273       break;
 274
 275     case 'F':
 276     case 'T':
 277       t = va_arg (*text->args_ptr, tree);
 278       break;
 279
 280     default:
 281       return false;
 282     }
 283
 284   if (set_locus)
 285     text->set_location (0, DECL_SOURCE_LOCATION (t), SHOW_RANGE_WITH_CARET);
 286
 287   if (DECL_P (t))
 288     {
 289       const char *n = DECL_NAME (t)
 290         ? identifier_to_locale (lang_hooks.decl_printable_name (t, 2))
 291         : _("<anonymous>");
 292       pp_string (pp, n);
 293     }
 294   else
 295     dump_generic_node (pp, t, 0, TDF_SLIM, 0);
 296
 297   return true;
 298 }
 299
 300 /* Set the locations of call sites along the inlining stack corresponding
 301    to the DIAGNOSTIC location.  */
 302
 303 static void
 304 set_inlining_locations (diagnostic_context *,
 305                         diagnostic_info *diagnostic)
 306 {
 307   location_t loc = diagnostic_location (diagnostic);
 308   tree block = LOCATION_BLOCK (loc);
 309
 310   /* Count the number of locations in system headers.  When all are,
 311      warnings are suppressed by -Wno-system-headers.  Otherwise, they
 312      involve some user code, possibly inlined into a function in a system
 313      header, and are not treated as coming from system headers.  */
 314   unsigned nsyslocs = 0;
 315
 316   /* Use a reference to the vector of locations for convenience.  */
 317   auto &ilocs = diagnostic->m_iinfo.m_ilocs;
 318
 319   while (block && TREE_CODE (block) == BLOCK
 320          && BLOCK_ABSTRACT_ORIGIN (block))
 321     {
 322       tree ao = BLOCK_ABSTRACT_ORIGIN (block);
 323       if (TREE_CODE (ao) == FUNCTION_DECL)
 324         {
 325           if (!diagnostic->m_iinfo.m_ao)
 326             diagnostic->m_iinfo.m_ao = block;
 327
 328           location_t bsloc = BLOCK_SOURCE_LOCATION (block);
 329           ilocs.safe_push (bsloc);
 330           if (in_system_header_at (bsloc))
 331             ++nsyslocs;
 332         }
 333       else if (TREE_CODE (ao) != BLOCK)
 334         break;
 335
 336       block = BLOCK_SUPERCONTEXT (block);
 337     }
 338
 339   if (ilocs.length ())
 340     {
 341       /* When there is an inlining context use the macro expansion
 342          location for the original location and bump up NSYSLOCS if
 343          it's in a system header since it's not counted above.  */
 344       location_t sysloc = expansion_point_location_if_in_system_header (loc);
 345       if (sysloc != loc)
 346         {
 347           loc = sysloc;
 348           ++nsyslocs;
 349         }
 350     }
 351   else
 352     {
 353       /* When there's no inlining context use the original location
 354          and set NSYSLOCS accordingly.  */
 355       nsyslocs = in_system_header_at (loc) != 0;
 356     }
 357
 358   ilocs.safe_push (loc);
 359
 360   /* Set if all locations are in a system header.  */
 361   diagnostic->m_iinfo.m_allsyslocs = nsyslocs == ilocs.length ();
 362
 363   if (tree *ao = pp_ti_abstract_origin (&diagnostic->message))
 364     *ao = (tree)diagnostic->m_iinfo.m_ao;
 365 }
 366
 367 /* Sets CONTEXT to use language independent diagnostics.  */
 368 void
 369 tree_diagnostics_defaults (diagnostic_context *context)
 370 {
 371   diagnostic_starter (context) = default_tree_diagnostic_starter;
 372   diagnostic_finalizer (context) = default_diagnostic_finalizer;
 373   diagnostic_format_decoder (context) = default_tree_printer;
 374   context->print_path = default_tree_diagnostic_path_printer;
 375   context->make_json_for_path = default_tree_make_json_for_path;
 376   context->set_locations_cb = set_inlining_locations;
 377   context->m_client_data_hooks = make_compiler_data_hooks ();
 378 }