ld/ldexp.h

   1 /* ldexp.h -
   2    Copyright (C) 1991-2022 Free Software Foundation, Inc.
   3
   4    This file is part of the GNU Binutils.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 #ifndef LDEXP_H
  22 #define LDEXP_H
  23
  24 /* The result of an expression tree */
  25 typedef struct {
  26   bfd_vma value;
  27   char *str;
  28   asection *section;
  29   bool valid_p;
  30 } etree_value_type;
  31
  32 enum node_tree_enum {
  33   etree_binary,
  34   etree_trinary,
  35   etree_unary,
  36   etree_name,
  37   etree_assign,
  38   etree_provide,
  39   etree_provided,
  40   etree_value,
  41   etree_assert,
  42   etree_rel
  43 };
  44
  45 typedef struct {
  46   int node_code;
  47   unsigned int lineno;
  48   const char *filename;
  49   enum node_tree_enum node_class;
  50 } node_type;
  51
  52 typedef union etree_union {
  53   node_type type;
  54   struct {
  55     node_type type;
  56     union etree_union *lhs;
  57     union etree_union *rhs;
  58   } binary;
  59   struct {
  60     node_type type;
  61     union etree_union *cond;
  62     union etree_union *lhs;
  63     union etree_union *rhs;
  64   } trinary;
  65   struct {
  66     node_type type;
  67     const char *dst;
  68     union etree_union *src;
  69     bool hidden;
  70   } assign;
  71   struct {
  72     node_type type;
  73     union etree_union *child;
  74   } unary;
  75   struct {
  76     node_type type;
  77     const char *name;
  78   } name;
  79   struct {
  80     node_type type;
  81     bfd_vma value;
  82     char *str;
  83   } value;
  84   struct {
  85     node_type type;
  86     asection *section;
  87     bfd_vma value;
  88   } rel;
  89   struct {
  90     node_type type;
  91     union etree_union *child;
  92     const char *message;
  93   } assert_s;
  94 } etree_type;
  95
  96 /* Expression evaluation control.  */
  97 typedef enum
  98 {
  99   /* Parsing linker script.  Will only return "valid" for expressions
 100      that evaluate to a constant.  */
 101   lang_first_phase_enum,
 102   /* Prior to section sizing.  */
 103   lang_mark_phase_enum,
 104   /* During section sizing.  */
 105   lang_allocating_phase_enum,
 106   /* During assignment of symbol values when relaxation in progress.  */
 107   lang_assigning_phase_enum,
 108   /* Final assignment of symbol values.  */
 109   lang_final_phase_enum,
 110   /* Run after symbol values have been fixed, for lang_map.  */
 111   lang_fixed_phase_enum
 112 } lang_phase_type;
 113
 114 union lang_statement_union;
 115
 116 enum phase_enum {
 117   /* We step through the first four states here as we see the
 118      associated linker script tokens.  */
 119   exp_seg_none,
 120   exp_seg_align_seen,
 121   exp_seg_relro_seen,
 122   exp_seg_end_seen,
 123   /* The last three states are final, and affect the value returned
 124      by XXX_SEGMENT_ALIGN.  */
 125   exp_seg_relro_adjust,
 126   exp_seg_adjust,
 127   exp_seg_done
 128 };
 129
 130 enum relro_enum {
 131   exp_seg_relro_none,
 132   exp_seg_relro_start,
 133   exp_seg_relro_end,
 134 };
 135
 136 typedef struct {
 137   enum phase_enum phase;
 138
 139   bfd_vma base, relro_offset, relro_end, end;
 140   /* MAXPAGESIZE and COMMMONPAGESIZE as passed to DATA_SEGMENT_ALIGN.
 141      relropagesize sets the alignment of the end of the relro segment.  */
 142   bfd_vma maxpagesize, commonpagesize, relropagesize;
 143
 144   enum relro_enum relro;
 145
 146   union lang_statement_union *relro_start_stat;
 147   union lang_statement_union *relro_end_stat;
 148 } seg_align_type;
 149
 150 struct ldexp_control {
 151   /* Modify expression evaluation depending on this.  */
 152   lang_phase_type phase;
 153
 154   /* Principally used for diagnostics.  */
 155   bool assigning_to_dot;
 156
 157   /* Set if the current expression used "dot", SEGMENT_START or
 158      ORIGIN, but not ABSOLUTE or combined symbols in a way that forces
 159      an absolute result.  Used in tracking symbols assigned from dot
 160      outside of output section statements, in order to later convert
 161      them from absolute.  */
 162   bool rel_from_abs;
 163
 164   /* If evaluating an assignment, the destination.  Cleared if an
 165      etree_name NAME matches this, to signal a self-assignment.
 166      Note that an etree_name DEFINED does not clear this field, nor
 167      does the false branch of a trinary expression.  */
 168   const char *assign_name;
 169
 170   /* If evaluating an assignment, the source if it is an expression
 171      referencing single etree_name NAME, or a trinary expression where
 172      the true branch references a single etree_name NAME.  */
 173   struct bfd_link_hash_entry *assign_src;
 174
 175   /* Working results.  */
 176   etree_value_type result;
 177   bfd_vma dot;
 178
 179   /* Current dot and section passed to ldexp folder.  */
 180   bfd_vma *dotp;
 181   asection *section;
 182
 183   /* State machine and results for DATASEG.  */
 184   seg_align_type dataseg;
 185 };
 186
 187 extern struct ldexp_control expld;
 188
 189 /* A maps from a segment name to a base address.  */
 190 typedef struct segment_struct {
 191   /* The next segment in the linked list.  */
 192   struct segment_struct *next;
 193   /* The name of the sgement.  */
 194   const char *name;
 195   /* The base address for the segment.  */
 196   bfd_vma value;
 197   /* True if a SEGMENT_START directive corresponding to this segment
 198      has been seen.  */
 199   bool used;
 200 } segment_type;
 201
 202 /* The segments specified by the user on the command-line.  */
 203 extern segment_type *segments;
 204
 205 typedef struct _fill_type fill_type;
 206
 207 etree_type *exp_intop
 208   (bfd_vma);
 209 etree_type *exp_bigintop
 210   (bfd_vma, char *);
 211 etree_type *exp_relop
 212   (asection *, bfd_vma);
 213 void exp_fold_tree
 214   (etree_type *, asection *, bfd_vma *);
 215 void exp_fold_tree_no_dot
 216   (etree_type *);
 217 etree_type *exp_binop
 218   (int, etree_type *, etree_type *);
 219 etree_type *exp_trinop
 220   (int,etree_type *, etree_type *, etree_type *);
 221 etree_type *exp_unop
 222   (int, etree_type *);
 223 etree_type *exp_nameop
 224   (int, const char *);
 225 etree_type *exp_assign
 226   (const char *, etree_type *, bool);
 227 etree_type *exp_defsym
 228   (const char *, etree_type *);
 229 etree_type *exp_provide
 230   (const char *, etree_type *, bool);
 231 etree_type *exp_assert
 232   (etree_type *, const char *);
 233 void exp_print_tree
 234   (etree_type *);
 235 bfd_vma exp_get_vma
 236   (etree_type *, bfd_vma, char *);
 237 int exp_get_power
 238   (etree_type *, char *);
 239 fill_type *exp_get_fill
 240   (etree_type *, fill_type *, char *);
 241 bfd_vma exp_get_abs_int
 242   (etree_type *, int, char *);
 243 void ldexp_init (void);
 244 void ldexp_finalize_syms (void);
 245 bool ldexp_is_final_sym_absolute (const struct bfd_link_hash_entry *);
 246 void ldexp_finish (void);
 247
 248 #endif