include/babeltrace/dwarf.h

   1 #ifndef _BABELTRACE_DWARF_H
   2 #define _BABELTRACE_DWARF_H
   3
   4 /*
   5  * Babeltrace - DWARF Information Reader
   6  *
   7  * Copyright 2015 Antoine Busque <abusque@efficios.com>
   8  *
   9  * Author: Antoine Busque <abusque@efficios.com>
  10  *
  11  * Permission is hereby granted, free of charge, to any person obtaining a copy
  12  * of this software and associated documentation files (the "Software"), to deal
  13  * in the Software without restriction, including without limitation the rights
  14  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  15  * copies of the Software, and to permit persons to whom the Software is
  16  * furnished to do so, subject to the following conditions:
  17  *
  18  * The above copyright notice and this permission notice shall be included in
  19  * all copies or substantial portions of the Software.
  20  *
  21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  22  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  23  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  24  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  25  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  26  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  27  * SOFTWARE.
  28  */
  29
  30 #include <stdint.h>
  31 #include <stdlib.h>
  32 #include <dwarf.h>
  33 #include <elfutils/libdw.h>
  34 #include <babeltrace/babeltrace-internal.h>
  35
  36 /*
  37  * bt_dwarf is a wrapper over libdw providing a nicer, higher-level
  38  * interface, to access basic debug information.
  39  */
  40
  41 /*
  42  * This structure corresponds to a single compilation unit (CU) for a
  43  * given set of debug information (Dwarf type).
  44  */
  45 struct bt_dwarf_cu {
  46         Dwarf *dwarf_info;
  47         /* Offset in bytes in the DWARF file to current CU header. */
  48         Dwarf_Off offset;
  49         /* Offset in bytes in the DWARF file to next CU header. */
  50         Dwarf_Off next_offset;
  51         /* Size in bytes of CU header */
  52         size_t header_size;
  53 };
  54
  55 /*
  56  * This structure represents a single debug information entry (DIE),
  57  * within a compilation unit (CU).
  58  */
  59 struct bt_dwarf_die {
  60         struct bt_dwarf_cu *cu;
  61         Dwarf_Die *dwarf_die;
  62         /*
  63          * A depth of 0 represents a root DIE, located in the DWARF
  64          * layout on the same level as its corresponding CU entry. Its
  65          * children DIEs will have a depth of 1, and so forth.
  66          */
  67         unsigned int depth;
  68 };
  69
  70 /**
  71  * Instantiate a structure to access compile units (CU) from a given
  72  * `dwarf_info`.
  73  *
  74  * @param dwarf_info    Dwarf instance
  75  * @returns             Pointer to the new bt_dwarf_cu on success,
  76  *                      NULL on failure.
  77  */
  78 BT_HIDDEN
  79 struct bt_dwarf_cu *bt_dwarf_cu_create(Dwarf *dwarf_info);
  80
  81 /**
  82  * Destroy the given bt_dwarf_cu instance.
  83  *
  84  * @param cu    bt_dwarf_cu instance
  85  */
  86 BT_HIDDEN
  87 void bt_dwarf_cu_destroy(struct bt_dwarf_cu *cu);
  88
  89 /**
  90  * Advance the compile unit `cu` to the next one.
  91  *
  92  * On success, `cu`'s offset is set to that of the current compile
  93  * unit in the executable. On failure, `cu` remains unchanged.
  94  *
  95  * @param cu    bt_dwarf_cu instance
  96  * @returns     0 on success, 1 if no next CU is available,
  97  *              -1 on failure
  98  */
  99 BT_HIDDEN
 100 int bt_dwarf_cu_next(struct bt_dwarf_cu *cu);
 101
 102 /**
 103  * Instantiate a structure to access debug information entries (DIE)
 104  * for the given compile unit `cu`.
 105  *
 106  * @param cu    bt_dwarf_cu instance
 107  * @returns     Pointer to the new bt_dwarf_die on success,
 108  *              NULL on failure.
 109  */
 110 BT_HIDDEN
 111 struct bt_dwarf_die *bt_dwarf_die_create(struct bt_dwarf_cu *cu);
 112
 113 /**
 114  * Destroy the given bt_dwarf_die instance.
 115  *
 116  * @param die   bt_dwarf_die instance
 117  */
 118 BT_HIDDEN
 119 void bt_dwarf_die_destroy(struct bt_dwarf_die *die);
 120
 121 /**
 122  * Advance the debug information entry `die` to its first child, if
 123  * any.
 124  *
 125  * @param die   bt_dwarf_die instance
 126  * @returns     0 on success, 1 if no child DIE is available,
 127  *              -1 on failure
 128  */
 129 BT_HIDDEN
 130 int bt_dwarf_die_child(struct bt_dwarf_die *die);
 131
 132 /**
 133  * Advance the debug information entry `die` to the next one.
 134  *
 135  * The next DIE is considered to be its sibling on the same level. The
 136  * only exception is when the depth of the given DIE is 0, i.e. a
 137  * newly created bt_dwarf_die, in which case next returns the first
 138  * DIE at depth 1.
 139  *
 140  * The reason for staying at a depth of 1 is that this is where all
 141  * the function DIEs (those with a tag value of DW_TAG_subprogram) are
 142  * located, from which more specific child DIEs can then be accessed
 143  * if needed via bt_dwarf_die_child.
 144  *
 145  * @param die   bt_dwarf_die instance
 146  * @returns     0 on success, 1 if no other siblings are available, -1 on
 147  *              failure
 148  */
 149 BT_HIDDEN
 150 int bt_dwarf_die_next(struct bt_dwarf_die *die);
 151
 152 /**
 153  * Get a DIE's tag.
 154  *
 155  * On success, the `tag` out parameter is set to the `die`'s tag's
 156  * value. It remains unchanged on failure.
 157  *
 158  * @param die   bt_dwarf_die instance
 159  * @param tag   Out parameter, the DIE's tag value
 160  * @returns     0 on success, -1 on failure.
 161  */
 162 BT_HIDDEN
 163 int bt_dwarf_die_get_tag(struct bt_dwarf_die *die, int *tag);
 164
 165 /**
 166  * Get a DIE's name.
 167  *
 168  * On success, the `name` out parameter is set to the DIE's name. It
 169  * remains unchanged on failure.
 170  *
 171  * @param die   bt_dwarf_die instance
 172  * @param name  Out parameter, the DIE's name
 173  * @returns     0 on success, -1 on failure
 174  */
 175 BT_HIDDEN
 176 int bt_dwarf_die_get_name(struct bt_dwarf_die *die, char **name);
 177
 178 /**
 179  * Get the full path to the DIE's callsite file.
 180  *
 181  * Only applies to DW_TAG_inlined_subroutine entries. The out
 182  * parameter `filename` is set on success, unchanged on failure.
 183  *
 184  * @param die           bt_dwarf_die instance
 185  * @param filename      Out parameter, the filename for the subroutine's
 186  *                      callsite
 187  * @returns             0 on success, -1 on failure
 188  */
 189 BT_HIDDEN
 190 int bt_dwarf_die_get_call_file(struct bt_dwarf_die *die, char **filename);
 191
 192 /**
 193  * Get line number for the DIE's callsite.
 194  *
 195  * Only applies to DW_TAG_inlined_subroutine entries. The out
 196  * parameter `line_no` is set on success, unchanged on failure.
 197  *
 198  * @param die           bt_dwarf_die instance
 199  * @param line_no       Out parameter, the line number for the
 200  *                      subroutine's callsite
 201  * @returns             0 on success, -1 on failure
 202  */
 203 BT_HIDDEN
 204 int bt_dwarf_die_get_call_line(struct bt_dwarf_die *die,
 205                 uint64_t *line_no);
 206
 207 /**
 208  * Verifies whether a given DIE contains the virtual memory address
 209  * `addr`.
 210  *
 211  * On success, the out parameter `contains` is set with the boolean
 212  * value indicating whether the DIE's range covers `addr`. On failure,
 213  * it remains unchanged.
 214  *
 215  * @param die           bt_dwarf_die instance
 216  * @param addr          The memory address to verify
 217  * @param contains      Out parameter, 1 if addr is contained,
 218  *                      0 if not
 219  * @returns             0 on succes, -1 on failure
 220  */
 221 BT_HIDDEN
 222 int bt_dwarf_die_contains_addr(struct bt_dwarf_die *die, uint64_t addr,
 223                 int *contains);
 224
 225 #endif  /* _BABELTRACE_DWARF_H */