gdb/macroscope.c

   1 /* Functions for deciding which macros are currently in scope.
   2    Copyright (C) 2002-2017 Free Software Foundation, Inc.
   3    Contributed by Red Hat, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21
  22 #include "macroscope.h"
  23 #include "symtab.h"
  24 #include "source.h"
  25 #include "target.h"
  26 #include "frame.h"
  27 #include "inferior.h"
  28 #include "complaints.h"
  29
  30 /* A table of user-defined macros.  Unlike the macro tables used for
  31    symtabs, this one uses xmalloc for all its allocation, not an
  32    obstack, and it doesn't bcache anything; it just xmallocs things.  So
  33    it's perfectly possible to remove things from this, or redefine
  34    things.  */
  35 struct macro_table *macro_user_macros;
  36
  37
  38 struct macro_scope *
  39 sal_macro_scope (struct symtab_and_line sal)
  40 {
  41   struct macro_source_file *main_file, *inclusion;
  42   struct macro_scope *ms;
  43   struct compunit_symtab *cust;
  44
  45   if (sal.symtab == NULL)
  46     return NULL;
  47   cust = SYMTAB_COMPUNIT (sal.symtab);
  48   if (COMPUNIT_MACRO_TABLE (cust) == NULL)
  49     return NULL;
  50
  51   ms = XNEW (struct macro_scope);
  52
  53   main_file = macro_main (COMPUNIT_MACRO_TABLE (cust));
  54   inclusion = macro_lookup_inclusion (main_file, sal.symtab->filename);
  55
  56   if (inclusion)
  57     {
  58       ms->file = inclusion;
  59       ms->line = sal.line;
  60     }
  61   else
  62     {
  63       /* There are, unfortunately, cases where a compilation unit can
  64          have a symtab for a source file that doesn't appear in the
  65          macro table.  For example, at the moment, Dwarf doesn't have
  66          any way in the .debug_macinfo section to describe the effect
  67          of #line directives, so if you debug a YACC parser you'll get
  68          a macro table which only mentions the .c files generated by
  69          YACC, but symtabs that mention the .y files consumed by YACC.
  70
  71          In the long run, we should extend the Dwarf macro info
  72          representation to handle #line directives, and get GCC to
  73          emit it.
  74
  75          For the time being, though, we'll just treat these as
  76          occurring at the end of the main source file.  */
  77       ms->file = main_file;
  78       ms->line = -1;
  79
  80       complaint (&symfile_complaints,
  81                  _("symtab found for `%s', but that file\n"
  82                  "is not covered in the compilation unit's macro information"),
  83                  symtab_to_filename_for_display (sal.symtab));
  84     }
  85
  86   return ms;
  87 }
  88
  89
  90 struct macro_scope *
  91 user_macro_scope (void)
  92 {
  93   struct macro_scope *ms;
  94
  95   ms = XNEW (struct macro_scope);
  96   ms->file = macro_main (macro_user_macros);
  97   ms->line = -1;
  98   return ms;
  99 }
 100
 101 struct macro_scope *
 102 default_macro_scope (void)
 103 {
 104   struct symtab_and_line sal;
 105   struct macro_scope *ms;
 106   struct frame_info *frame;
 107   CORE_ADDR pc;
 108
 109   /* If there's a selected frame, use its PC.  */
 110   frame = deprecated_safe_get_selected_frame ();
 111   if (frame && get_frame_pc_if_available (frame, &pc))
 112     sal = find_pc_line (pc, 0);
 113
 114   /* Fall back to the current listing position.  */
 115   else
 116     {
 117       /* Don't call select_source_symtab here.  That can raise an
 118          error if symbols aren't loaded, but GDB calls the expression
 119          evaluator in all sorts of contexts.
 120
 121          For example, commands like `set width' call the expression
 122          evaluator to evaluate their numeric arguments.  If the
 123          current language is C, then that may call this function to
 124          choose a scope for macro expansion.  If you don't have any
 125          symbol files loaded, then get_current_or_default would raise an
 126          error.  But `set width' shouldn't raise an error just because
 127          it can't decide which scope to macro-expand its argument in.  */
 128       struct symtab_and_line cursal =
 129                         get_current_source_symtab_and_line ();
 130
 131       sal.symtab = cursal.symtab;
 132       sal.line = cursal.line;
 133     }
 134
 135   ms = sal_macro_scope (sal);
 136   if (! ms)
 137     ms = user_macro_scope ();
 138
 139   return ms;
 140 }
 141
 142
 143 /* Look up the definition of the macro named NAME in scope at the source
 144    location given by BATON, which must be a pointer to a `struct
 145    macro_scope' structure.  */
 146 struct macro_definition *
 147 standard_macro_lookup (const char *name, void *baton)
 148 {
 149   struct macro_scope *ms = (struct macro_scope *) baton;
 150   struct macro_definition *result;
 151
 152   /* Give user-defined macros priority over all others.  */
 153   result = macro_lookup_definition (macro_main (macro_user_macros), -1, name);
 154   if (! result)
 155     result = macro_lookup_definition (ms->file, ms->line, name);
 156   return result;
 157 }
 158
 159 void
 160 _initialize_macroscope (void)
 161 {
 162   macro_user_macros = new_macro_table (NULL, NULL, NULL);
 163   macro_set_main (macro_user_macros, "<user-defined>");
 164   macro_allow_redefinitions (macro_user_macros);
 165 }