gdb/gdb_bfd.h

   1 /* Definitions for BFD wrappers used by GDB.
   2
   3    Copyright (C) 2011-2021 Free Software Foundation, 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 #ifndef GDB_BFD_H
  21 #define GDB_BFD_H
  22
  23 #include "registry.h"
  24 #include "gdbsupport/byte-vector.h"
  25 #include "gdbsupport/gdb_ref_ptr.h"
  26 #include "gdbsupport/next-iterator.h"
  27
  28 DECLARE_REGISTRY (bfd);
  29
  30 /* If supplied a path starting with this sequence, gdb_bfd_open will
  31    open BFDs using target fileio operations.  */
  32
  33 #define TARGET_SYSROOT_PREFIX "target:"
  34
  35 /* Returns nonzero if NAME starts with TARGET_SYSROOT_PREFIX, zero
  36    otherwise.  */
  37
  38 int is_target_filename (const char *name);
  39
  40 /* Returns nonzero if the filename associated with ABFD starts with
  41    TARGET_SYSROOT_PREFIX, zero otherwise.  */
  42
  43 int gdb_bfd_has_target_filename (struct bfd *abfd);
  44
  45 /* Increment the reference count of ABFD.  It is fine for ABFD to be
  46    NULL; in this case the function does nothing.  */
  47
  48 void gdb_bfd_ref (struct bfd *abfd);
  49
  50 /* Decrement the reference count of ABFD.  If this is the last
  51    reference, ABFD will be freed.  If ABFD is NULL, this function does
  52    nothing.  */
  53
  54 void gdb_bfd_unref (struct bfd *abfd);
  55
  56 /* A policy class for gdb::ref_ptr for BFD reference counting.  */
  57 struct gdb_bfd_ref_policy
  58 {
  59   static void incref (struct bfd *abfd)
  60   {
  61     gdb_bfd_ref (abfd);
  62   }
  63
  64   static void decref (struct bfd *abfd)
  65   {
  66     gdb_bfd_unref (abfd);
  67   }
  68 };
  69
  70 /* A gdb::ref_ptr that has been specialized for BFD objects.  */
  71 typedef gdb::ref_ptr<struct bfd, gdb_bfd_ref_policy> gdb_bfd_ref_ptr;
  72
  73 /* Open a read-only (FOPEN_RB) BFD given arguments like bfd_fopen.
  74    If NAME starts with TARGET_SYSROOT_PREFIX then the BFD will be
  75    opened using target fileio operations if necessary.  Returns NULL
  76    on error.  On success, returns a new reference to the BFD.  BFDs
  77    returned by this call are shared among all callers opening the same
  78    file.  If FD is not -1, then after this call it is owned by BFD.
  79    If the BFD was not accessed using target fileio operations then the
  80    filename associated with the BFD and accessible with
  81    bfd_get_filename will not be exactly NAME but rather NAME with
  82    TARGET_SYSROOT_PREFIX stripped.  If WARN_IF_SLOW is true, print a
  83    warning message if the file is being accessed over a link that may
  84    be slow.  */
  85
  86 gdb_bfd_ref_ptr gdb_bfd_open (const char *name, const char *target,
  87                               int fd = -1, bool warn_if_slow = true);
  88
  89 /* Mark the CHILD BFD as being a member of PARENT.  Also, increment
  90    the reference count of CHILD.  Calling this function ensures that
  91    as along as CHILD remains alive, PARENT will as well.  Both CHILD
  92    and PARENT must be non-NULL.  This can be called more than once
  93    with the same arguments; but it is not allowed to call it for a
  94    single CHILD with different values for PARENT.  */
  95
  96 void gdb_bfd_mark_parent (bfd *child, bfd *parent);
  97
  98 /* Mark INCLUDEE as being included by INCLUDER.
  99    This is used to associate the life time of INCLUDEE with INCLUDER.
 100    For example, with Fission, one file can refer to debug info in another
 101    file, and internal tables we build for the main file (INCLUDER) may refer
 102    to data contained in INCLUDEE.  Therefore we want to keep INCLUDEE around
 103    at least as long as INCLUDER exists.
 104
 105    Note that this is different than gdb_bfd_mark_parent because in our case
 106    lifetime tracking is based on the "parent" whereas in gdb_bfd_mark_parent
 107    lifetime tracking is based on the "child".  Plus in our case INCLUDEE could
 108    have multiple different "parents".  */
 109
 110 void gdb_bfd_record_inclusion (bfd *includer, bfd *includee);
 111
 112 /* Try to read or map the contents of the section SECT.  If successful, the
 113    section data is returned and *SIZE is set to the size of the section data;
 114    this may not be the same as the size according to bfd_section_size if the
 115    section was compressed.  The returned section data is associated with the BFD
 116    and will be destroyed when the BFD is destroyed.  There is no other way to
 117    free it; for temporary uses of section data, see bfd_malloc_and_get_section.
 118    SECT may not have relocations.  If there is an error reading the section,
 119    this issues a warning, sets *SIZE to 0, and returns NULL.  */
 120
 121 const gdb_byte *gdb_bfd_map_section (asection *section, bfd_size_type *size);
 122
 123 /* Compute the CRC for ABFD.  The CRC is used to find and verify
 124    separate debug files.  When successful, this fills in *CRC_OUT and
 125    returns 1.  Otherwise, this issues a warning and returns 0.  */
 126
 127 int gdb_bfd_crc (struct bfd *abfd, unsigned long *crc_out);
 128
 129 \f
 130
 131 /* A wrapper for bfd_fopen that initializes the gdb-specific reference
 132    count.  */
 133
 134 gdb_bfd_ref_ptr gdb_bfd_fopen (const char *, const char *, const char *, int);
 135
 136 /* A wrapper for bfd_openr that initializes the gdb-specific reference
 137    count.  */
 138
 139 gdb_bfd_ref_ptr gdb_bfd_openr (const char *, const char *);
 140
 141 /* A wrapper for bfd_openw that initializes the gdb-specific reference
 142    count.  */
 143
 144 gdb_bfd_ref_ptr gdb_bfd_openw (const char *, const char *);
 145
 146 /* A wrapper for bfd_openr_iovec that initializes the gdb-specific
 147    reference count.  */
 148
 149 gdb_bfd_ref_ptr gdb_bfd_openr_iovec (const char *filename, const char *target,
 150                                      void *(*open_func) (struct bfd *nbfd,
 151                                                          void *open_closure),
 152                                      void *open_closure,
 153                                      file_ptr (*pread_func) (struct bfd *nbfd,
 154                                                              void *stream,
 155                                                              void *buf,
 156                                                              file_ptr nbytes,
 157                                                              file_ptr offset),
 158                                      int (*close_func) (struct bfd *nbfd,
 159                                                         void *stream),
 160                                      int (*stat_func) (struct bfd *abfd,
 161                                                        void *stream,
 162                                                        struct stat *sb));
 163
 164 /* A wrapper for bfd_openr_next_archived_file that initializes the
 165    gdb-specific reference count.  */
 166
 167 gdb_bfd_ref_ptr gdb_bfd_openr_next_archived_file (bfd *archive, bfd *previous);
 168
 169
 170 \f
 171
 172 /* Return the index of the BFD section SECTION.  Ordinarily this is
 173    just the section's index, but for some special sections, like
 174    bfd_com_section_ptr, it will be a synthesized value.  */
 175
 176 int gdb_bfd_section_index (bfd *abfd, asection *section);
 177
 178
 179 /* Like bfd_count_sections, but include any possible global sections,
 180    like bfd_com_section_ptr.  */
 181
 182 int gdb_bfd_count_sections (bfd *abfd);
 183
 184 /* Return true if any section requires relocations, false
 185    otherwise.  */
 186
 187 int gdb_bfd_requires_relocations (bfd *abfd);
 188
 189 /* Alternative to bfd_get_full_section_contents that returns the section
 190    contents in *CONTENTS, instead of an allocated buffer.
 191
 192    Return true on success, false otherwise.  */
 193
 194 bool gdb_bfd_get_full_section_contents (bfd *abfd, asection *section,
 195                                         gdb::byte_vector *contents);
 196
 197 /* Create and initialize a BFD handle from a target in-memory range.  */
 198
 199 gdb_bfd_ref_ptr gdb_bfd_open_from_target_memory (CORE_ADDR addr, ULONGEST size,
 200                                                  const char *target,
 201                                                  const char *filename = nullptr);
 202
 203 /* Range adapter for a BFD's sections.
 204
 205    To be used as:
 206
 207      for (asection *sect : gdb_bfd_all_sections (bfd))
 208        ... use SECT ...
 209  */
 210
 211 using gdb_bfd_section_iterator = next_iterator<asection>;
 212 using gdb_bfd_section_range = next_adapter<asection, gdb_bfd_section_iterator>;
 213
 214 static inline gdb_bfd_section_range
 215 gdb_bfd_sections (bfd *abfd)
 216 {
 217   return gdb_bfd_section_range (abfd->sections);
 218 }
 219
 220 static inline gdb_bfd_section_range
 221 gdb_bfd_sections (const gdb_bfd_ref_ptr &abfd)
 222 {
 223   return gdb_bfd_section_range (abfd->sections);
 224 };
 225
 226 #endif /* GDB_BFD_H */