gdb/macroscope.c

   1 /* Functions for deciding which macros are currently in scope.
   2    Copyright (C) 2002-2019 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 gdb::unique_xmalloc_ptr<struct macro_scope>
  39 sal_macro_scope (struct symtab_and_line sal)
  40 {
  41   struct macro_source_file *main_file, *inclusion;
  42   struct compunit_symtab *cust;
  43
  44   if (sal.symtab == NULL)
  45     return NULL;
  46   cust = SYMTAB_COMPUNIT (sal.symtab);
  47   if (COMPUNIT_MACRO_TABLE (cust) == NULL)
  48     return NULL;
  49
  50   gdb::unique_xmalloc_ptr<struct macro_scope> ms (XNEW (struct macro_scope));
  51
  52   main_file = macro_main (COMPUNIT_MACRO_TABLE (cust));
  53   inclusion = macro_lookup_inclusion (main_file, sal.symtab->filename);
  54
  55   if (inclusion)
  56     {
  57       ms->file = inclusion;
  58       ms->line = sal.line;
  59     }
  60   else
  61     {
  62       /* There are, unfortunately, cases where a compilation unit can
  63          have a symtab for a source file that doesn't appear in the
  64          macro table.  For example, at the moment, Dwarf doesn't have
  65          any way in the .debug_macinfo section to describe the effect
  66          of #line directives, so if you debug a YACC parser you'll get
  67          a macro table which only mentions the .c files generated by
  68          YACC, but symtabs that mention the .y files consumed by YACC.
  69
  70          In the long run, we should extend the Dwarf macro info
  71          representation to handle #line directives, and get GCC to
  72          emit it.
  73
  74          For the time being, though, we'll just treat these as
  75          occurring at the end of the main source file.  */
  76       ms->file = main_file;
  77       ms->line = -1;
  78
  79       complaint (_("symtab found for `%s', but that file\n"
  80                  "is not covered in the compilation unit's macro information"),
  81                  symtab_to_filename_for_display (sal.symtab));
  82     }
  83
  84   return ms;
  85 }
  86
  87
  88 gdb::unique_xmalloc_ptr<struct macro_scope>
  89 user_macro_scope (void)
  90 {
  91   gdb::unique_xmalloc_ptr<struct macro_scope> ms (XNEW (struct macro_scope));
  92   ms->file = macro_main (macro_user_macros);
  93   ms->line = -1;
  94   return ms;
  95 }
  96
  97 gdb::unique_xmalloc_ptr<struct macro_scope>
  98 default_macro_scope (void)
  99 {
 100   struct symtab_and_line sal;
 101   gdb::unique_xmalloc_ptr<struct macro_scope> ms;
 102   struct frame_info *frame;
 103   CORE_ADDR pc;
 104
 105   /* If there's a selected frame, use its PC.  */
 106   frame = deprecated_safe_get_selected_frame ();
 107   if (frame && get_frame_pc_if_available (frame, &pc))
 108     sal = find_pc_line (pc, 0);
 109
 110   /* Fall back to the current listing position.  */
 111   else
 112     {
 113       /* Don't call select_source_symtab here.  That can raise an
 114          error if symbols aren't loaded, but GDB calls the expression
 115          evaluator in all sorts of contexts.
 116
 117          For example, commands like `set width' call the expression
 118          evaluator to evaluate their numeric arguments.  If the
 119          current language is C, then that may call this function to
 120          choose a scope for macro expansion.  If you don't have any
 121          symbol files loaded, then get_current_or_default would raise an
 122          error.  But `set width' shouldn't raise an error just because
 123          it can't decide which scope to macro-expand its argument in.  */
 124       struct symtab_and_line cursal =
 125                         get_current_source_symtab_and_line ();
 126
 127       sal.symtab = cursal.symtab;
 128       sal.line = cursal.line;
 129     }
 130
 131   ms = sal_macro_scope (sal);
 132   if (! ms)
 133     ms = user_macro_scope ();
 134
 135   return ms;
 136 }
 137
 138
 139 /* Look up the definition of the macro named NAME in scope at the source
 140    location given by BATON, which must be a pointer to a `struct
 141    macro_scope' structure.  */
 142 struct macro_definition *
 143 standard_macro_lookup (const char *name, void *baton)
 144 {
 145   struct macro_scope *ms = (struct macro_scope *) baton;
 146   struct macro_definition *result;
 147
 148   /* Give user-defined macros priority over all others.  */
 149   result = macro_lookup_definition (macro_main (macro_user_macros), -1, name);
 150   if (! result)
 151     result = macro_lookup_definition (ms->file, ms->line, name);
 152   return result;
 153 }
 154
 155 void
 156 _initialize_macroscope (void)
 157 {
 158   macro_user_macros = new_macro_table (NULL, NULL, NULL);
 159   macro_set_main (macro_user_macros, "<user-defined>");
 160   macro_allow_redefinitions (macro_user_macros);
 161 }