ld/ldexp.h

   1 /* ldexp.h -
   2    Copyright (C) 1991-2023 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 struct lang_output_section_statement_struct;
 137
 138 typedef struct {
 139   enum phase_enum phase;
 140
 141   bfd_vma base, relro_offset, relro_end, end;
 142   /* MAXPAGESIZE and COMMMONPAGESIZE as passed to DATA_SEGMENT_ALIGN.
 143      relropagesize sets the alignment of the end of the relro segment.  */
 144   bfd_vma maxpagesize, commonpagesize, relropagesize;
 145
 146   enum relro_enum relro;
 147
 148   union lang_statement_union *relro_start_stat;
 149   union lang_statement_union *relro_end_stat;
 150 } seg_align_type;
 151
 152 struct ldexp_control {
 153   /* Modify expression evaluation depending on this.  */
 154   lang_phase_type phase;
 155
 156   /* Principally used for diagnostics.  */
 157   bool assigning_to_dot;
 158
 159   /* Set if the current expression used "dot", SEGMENT_START or
 160      ORIGIN, but not ABSOLUTE or combined symbols in a way that forces
 161      an absolute result.  Used in tracking symbols assigned from dot
 162      outside of output section statements, in order to later convert
 163      them from absolute.  */
 164   bool rel_from_abs;
 165
 166   /* If evaluating an assignment, the destination.  Cleared if an
 167      etree_name NAME matches this, to signal a self-assignment.
 168      Note that an etree_name DEFINED does not clear this field, nor
 169      does the false branch of a trinary expression.  */
 170   const char *assign_name;
 171
 172   /* If evaluating an assignment, the source if it is an expression
 173      referencing single etree_name NAME, or a trinary expression where
 174      the true branch references a single etree_name NAME.  */
 175   struct bfd_link_hash_entry *assign_src;
 176
 177   /* Working results.  */
 178   etree_value_type result;
 179   bfd_vma dot;
 180
 181   /* Current dot and section passed to ldexp folder.  SECTION will be
 182      bfd_abs_section for expressions outside of an output section
 183      statement.  */
 184   bfd_vma *dotp;
 185   asection *section;
 186
 187   /* Last output section statement.  For expressions within an output
 188      section statement, this will be the current output section
 189      statement being processed.  */
 190   struct lang_output_section_statement_struct *last_os;
 191
 192   /* State machine and results for DATASEG.  */
 193   seg_align_type dataseg;
 194 };
 195
 196 extern struct ldexp_control expld;
 197
 198 /* A maps from a segment name to a base address.  */
 199 typedef struct segment_struct {
 200   /* The next segment in the linked list.  */
 201   struct segment_struct *next;
 202   /* The name of the sgement.  */
 203   const char *name;
 204   /* The base address for the segment.  */
 205   bfd_vma value;
 206   /* True if a SEGMENT_START directive corresponding to this segment
 207      has been seen.  */
 208   bool used;
 209 } segment_type;
 210
 211 /* The segments specified by the user on the command-line.  */
 212 extern segment_type *segments;
 213
 214 typedef struct _fill_type fill_type;
 215
 216 etree_type *exp_intop
 217   (bfd_vma);
 218 etree_type *exp_bigintop
 219   (bfd_vma, char *);
 220 etree_type *exp_relop
 221   (asection *, bfd_vma);
 222 void exp_fold_tree
 223   (etree_type *, struct lang_output_section_statement_struct *,
 224    asection *, bfd_vma *);
 225 void exp_fold_tree_no_dot
 226   (etree_type *, struct lang_output_section_statement_struct *);
 227 etree_type *exp_binop
 228   (int, etree_type *, etree_type *);
 229 etree_type *exp_trinop
 230   (int,etree_type *, etree_type *, etree_type *);
 231 etree_type *exp_unop
 232   (int, etree_type *);
 233 etree_type *exp_nameop
 234   (int, const char *);
 235 etree_type *exp_assign
 236   (const char *, etree_type *, bool);
 237 etree_type *exp_defsym
 238   (const char *, etree_type *);
 239 etree_type *exp_provide
 240   (const char *, etree_type *, bool);
 241 etree_type *exp_assert
 242   (etree_type *, const char *);
 243 void exp_print_tree
 244   (etree_type *);
 245 bfd_vma exp_get_vma
 246   (etree_type *, struct lang_output_section_statement_struct *, bfd_vma, char *);
 247 int exp_get_power
 248   (etree_type *, struct lang_output_section_statement_struct *, char *);
 249 fill_type *exp_get_fill
 250   (etree_type *, fill_type *, char *);
 251 bfd_vma exp_get_abs_int
 252   (etree_type *, int, char *);
 253 void ldexp_init (void);
 254 void ldexp_finalize_syms (void);
 255 bool ldexp_is_final_sym_absolute (const struct bfd_link_hash_entry *);
 256 void ldexp_finish (void);
 257
 258 #endif