gdb/dwarf2loc.h

   1 /* DWARF 2 location expression support for GDB.
   2
   3    Copyright (C) 2003-2014 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 #if !defined (DWARF2LOC_H)
  21 #define DWARF2LOC_H
  22
  23 #include "dwarf2expr.h"
  24
  25 struct symbol_computed_ops;
  26 struct objfile;
  27 struct dwarf2_per_cu_data;
  28 struct dwarf2_loclist_baton;
  29 struct agent_expr;
  30 struct axs_value;
  31
  32 /* This header is private to the DWARF-2 reader.  It is shared between
  33    dwarf2read.c and dwarf2loc.c.  */
  34
  35 /* `set debug entry-values' setting.  */
  36 extern unsigned int entry_values_debug;
  37
  38 /* Return the OBJFILE associated with the compilation unit CU.  If CU
  39    came from a separate debuginfo file, then the master objfile is
  40    returned.  */
  41 struct objfile *dwarf2_per_cu_objfile (struct dwarf2_per_cu_data *cu);
  42
  43 /* Return the address size given in the compilation unit header for CU.  */
  44 int dwarf2_per_cu_addr_size (struct dwarf2_per_cu_data *cu);
  45
  46 /* Return the DW_FORM_ref_addr size given in the compilation unit header for
  47    CU.  */
  48 int dwarf2_per_cu_ref_addr_size (struct dwarf2_per_cu_data *cu);
  49
  50 /* Return the offset size given in the compilation unit header for CU.  */
  51 int dwarf2_per_cu_offset_size (struct dwarf2_per_cu_data *cu);
  52
  53 /* Return the text offset of the CU.  The returned offset comes from
  54    this CU's objfile.  If this objfile came from a separate debuginfo
  55    file, then the offset may be different from the corresponding
  56    offset in the parent objfile.  */
  57 CORE_ADDR dwarf2_per_cu_text_offset (struct dwarf2_per_cu_data *cu);
  58
  59 /* Find a particular location expression from a location list.  */
  60 const gdb_byte *dwarf2_find_location_expression
  61   (struct dwarf2_loclist_baton *baton,
  62    size_t *locexpr_length,
  63    CORE_ADDR pc);
  64
  65 struct dwarf2_locexpr_baton dwarf2_fetch_die_loc_sect_off
  66   (sect_offset offset_in_cu, struct dwarf2_per_cu_data *per_cu,
  67    CORE_ADDR (*get_frame_pc) (void *baton),
  68    void *baton);
  69
  70 struct dwarf2_locexpr_baton dwarf2_fetch_die_loc_cu_off
  71   (cu_offset offset_in_cu, struct dwarf2_per_cu_data *per_cu,
  72    CORE_ADDR (*get_frame_pc) (void *baton),
  73    void *baton);
  74
  75 extern const gdb_byte *dwarf2_fetch_constant_bytes (sect_offset,
  76                                                     struct dwarf2_per_cu_data *,
  77                                                     struct obstack *,
  78                                                     LONGEST *);
  79
  80 struct type *dwarf2_get_die_type (cu_offset die_offset,
  81                                   struct dwarf2_per_cu_data *per_cu);
  82
  83 /* Find the frame base information for FRAMEFUNC at PC.  START is an
  84    out parameter which is set to point to the DWARF expression to
  85    compute.  LENGTH is an out parameter which is set to the length of
  86    the DWARF expression.  This throws an exception on error or if an
  87    expression is not found; the returned length will never be
  88    zero.  */
  89
  90 extern void func_get_frame_base_dwarf_block (struct symbol *framefunc,
  91                                              CORE_ADDR pc,
  92                                              const gdb_byte **start,
  93                                              size_t *length);
  94
  95 /* Evaluate a location description, starting at DATA and with length
  96    SIZE, to find the current location of variable of TYPE in the context
  97    of FRAME.  */
  98
  99 struct value *dwarf2_evaluate_loc_desc (struct type *type,
 100                                         struct frame_info *frame,
 101                                         const gdb_byte *data,
 102                                         size_t size,
 103                                         struct dwarf2_per_cu_data *per_cu);
 104
 105 /* Converts a dynamic property into a static one.  ADDRESS is the address
 106    of the object currently being evaluated and might be nedded.
 107    Returns 1 if PROP could be converted and the static value is passed back
 108    into VALUE, otherwise returns 0.  */
 109
 110 int dwarf2_evaluate_property (const struct dynamic_prop *prop,
 111                               CORE_ADDR address,
 112                               CORE_ADDR *value);
 113
 114 CORE_ADDR dwarf2_read_addr_index (struct dwarf2_per_cu_data *per_cu,
 115                                   unsigned int addr_index);
 116
 117 /* The symbol location baton types used by the DWARF-2 reader (i.e.
 118    SYMBOL_LOCATION_BATON for a LOC_COMPUTED symbol).  "struct
 119    dwarf2_locexpr_baton" is for a symbol with a single location
 120    expression; "struct dwarf2_loclist_baton" is for a symbol with a
 121    location list.  */
 122
 123 struct dwarf2_locexpr_baton
 124 {
 125   /* Pointer to the start of the location expression.  Valid only if SIZE is
 126      not zero.  */
 127   const gdb_byte *data;
 128
 129   /* Length of the location expression.  For optimized out expressions it is
 130      zero.  */
 131   size_t size;
 132
 133   /* The compilation unit containing the symbol whose location
 134      we're computing.  */
 135   struct dwarf2_per_cu_data *per_cu;
 136 };
 137
 138 struct dwarf2_loclist_baton
 139 {
 140   /* The initial base address for the location list, based on the compilation
 141      unit.  */
 142   CORE_ADDR base_address;
 143
 144   /* Pointer to the start of the location list.  */
 145   const gdb_byte *data;
 146
 147   /* Length of the location list.  */
 148   size_t size;
 149
 150   /* The compilation unit containing the symbol whose location
 151      we're computing.  */
 152   struct dwarf2_per_cu_data *per_cu;
 153
 154   /* Non-zero if the location list lives in .debug_loc.dwo.
 155      The format of entries in this section are different.  */
 156   unsigned char from_dwo;
 157 };
 158
 159 /* A dynamic property is either expressed as a single location expression
 160    or a location list.  If the property is an indirection, pointing to
 161    another die, keep track of the targeted type in REFERENCED_TYPE.  */
 162
 163 struct dwarf2_property_baton
 164 {
 165   /* If the property is an indirection, we need to evaluate the location
 166      LOCEXPR or LOCLIST in the context of the type REFERENCED_TYPE.
 167      If NULL, the location is the actual value of the property.  */
 168   struct type *referenced_type;
 169   union
 170   {
 171     /* Location expression.  */
 172     struct dwarf2_locexpr_baton locexpr;
 173
 174     /* Location list to be evaluated in the context of REFERENCED_TYPE.  */
 175     struct dwarf2_loclist_baton loclist;
 176   };
 177 };
 178
 179 extern const struct symbol_computed_ops dwarf2_locexpr_funcs;
 180 extern const struct symbol_computed_ops dwarf2_loclist_funcs;
 181
 182 extern const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs;
 183 extern const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs;
 184
 185 /* Compile a DWARF location expression to an agent expression.
 186
 187    EXPR is the agent expression we are building.
 188    LOC is the agent value we modify.
 189    ARCH is the architecture.
 190    ADDR_SIZE is the size of addresses, in bytes.
 191    OP_PTR is the start of the location expression.
 192    OP_END is one past the last byte of the location expression.
 193
 194    This will throw an exception for various kinds of errors -- for
 195    example, if the expression cannot be compiled, or if the expression
 196    is invalid.  */
 197
 198 extern void dwarf2_compile_expr_to_ax (struct agent_expr *expr,
 199                                        struct axs_value *loc,
 200                                        struct gdbarch *arch,
 201                                        unsigned int addr_size,
 202                                        const gdb_byte *op_ptr,
 203                                        const gdb_byte *op_end,
 204                                        struct dwarf2_per_cu_data *per_cu);
 205
 206 /* Determined tail calls for constructing virtual tail call frames.  */
 207
 208 struct call_site_chain
 209   {
 210     /* Initially CALLERS == CALLEES == LENGTH.  For partially ambiguous result
 211        CALLERS + CALLEES < LENGTH.  */
 212     int callers, callees, length;
 213
 214     /* Variably sized array with LENGTH elements.  Later [0..CALLERS-1] contain
 215        top (GDB "prev") sites and [LENGTH-CALLEES..LENGTH-1] contain bottom
 216        (GDB "next") sites.  One is interested primarily in the PC field.  */
 217     struct call_site *call_site[1];
 218   };
 219
 220 struct call_site_stuff;
 221 extern struct call_site_chain *call_site_find_chain (struct gdbarch *gdbarch,
 222                                                      CORE_ADDR caller_pc,
 223                                                      CORE_ADDR callee_pc);
 224
 225 #endif /* dwarf2loc.h */