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 /* Evaluate a location description, starting at DATA and with length
  84    SIZE, to find the current location of variable of TYPE in the context
  85    of FRAME.  */
  86
  87 struct value *dwarf2_evaluate_loc_desc (struct type *type,
  88                                         struct frame_info *frame,
  89                                         const gdb_byte *data,
  90                                         size_t size,
  91                                         struct dwarf2_per_cu_data *per_cu);
  92
  93 /* Converts a dynamic property into a static one.  ADDRESS is the address
  94    of the object currently being evaluated and might be nedded.
  95    Returns 1 if PROP could be converted and the static value is passed back
  96    into VALUE, otherwise returns 0.  */
  97
  98 int dwarf2_evaluate_property (const struct dynamic_prop *prop,
  99                               CORE_ADDR address,
 100                               CORE_ADDR *value);
 101
 102 CORE_ADDR dwarf2_read_addr_index (struct dwarf2_per_cu_data *per_cu,
 103                                   unsigned int addr_index);
 104
 105 /* The symbol location baton types used by the DWARF-2 reader (i.e.
 106    SYMBOL_LOCATION_BATON for a LOC_COMPUTED symbol).  "struct
 107    dwarf2_locexpr_baton" is for a symbol with a single location
 108    expression; "struct dwarf2_loclist_baton" is for a symbol with a
 109    location list.  */
 110
 111 struct dwarf2_locexpr_baton
 112 {
 113   /* Pointer to the start of the location expression.  Valid only if SIZE is
 114      not zero.  */
 115   const gdb_byte *data;
 116
 117   /* Length of the location expression.  For optimized out expressions it is
 118      zero.  */
 119   size_t size;
 120
 121   /* The compilation unit containing the symbol whose location
 122      we're computing.  */
 123   struct dwarf2_per_cu_data *per_cu;
 124 };
 125
 126 struct dwarf2_loclist_baton
 127 {
 128   /* The initial base address for the location list, based on the compilation
 129      unit.  */
 130   CORE_ADDR base_address;
 131
 132   /* Pointer to the start of the location list.  */
 133   const gdb_byte *data;
 134
 135   /* Length of the location list.  */
 136   size_t size;
 137
 138   /* The compilation unit containing the symbol whose location
 139      we're computing.  */
 140   struct dwarf2_per_cu_data *per_cu;
 141
 142   /* Non-zero if the location list lives in .debug_loc.dwo.
 143      The format of entries in this section are different.  */
 144   unsigned char from_dwo;
 145 };
 146
 147 /* A dynamic property is either expressed as a single location expression
 148    or a location list.  If the property is an indirection, pointing to
 149    another die, keep track of the targeted type in REFERENCED_TYPE.  */
 150
 151 struct dwarf2_property_baton
 152 {
 153   /* If the property is an indirection, we need to evaluate the location
 154      LOCEXPR or LOCLIST in the context of the type REFERENCED_TYPE.
 155      If NULL, the location is the actual value of the property.  */
 156   struct type *referenced_type;
 157   union
 158   {
 159     /* Location expression.  */
 160     struct dwarf2_locexpr_baton locexpr;
 161
 162     /* Location list to be evaluated in the context of REFERENCED_TYPE.  */
 163     struct dwarf2_loclist_baton loclist;
 164   };
 165 };
 166
 167 extern const struct symbol_computed_ops dwarf2_locexpr_funcs;
 168 extern const struct symbol_computed_ops dwarf2_loclist_funcs;
 169
 170 extern const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs;
 171 extern const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs;
 172
 173 /* Compile a DWARF location expression to an agent expression.
 174
 175    EXPR is the agent expression we are building.
 176    LOC is the agent value we modify.
 177    ARCH is the architecture.
 178    ADDR_SIZE is the size of addresses, in bytes.
 179    OP_PTR is the start of the location expression.
 180    OP_END is one past the last byte of the location expression.
 181
 182    This will throw an exception for various kinds of errors -- for
 183    example, if the expression cannot be compiled, or if the expression
 184    is invalid.  */
 185
 186 extern void dwarf2_compile_expr_to_ax (struct agent_expr *expr,
 187                                        struct axs_value *loc,
 188                                        struct gdbarch *arch,
 189                                        unsigned int addr_size,
 190                                        const gdb_byte *op_ptr,
 191                                        const gdb_byte *op_end,
 192                                        struct dwarf2_per_cu_data *per_cu);
 193
 194 /* Determined tail calls for constructing virtual tail call frames.  */
 195
 196 struct call_site_chain
 197   {
 198     /* Initially CALLERS == CALLEES == LENGTH.  For partially ambiguous result
 199        CALLERS + CALLEES < LENGTH.  */
 200     int callers, callees, length;
 201
 202     /* Variably sized array with LENGTH elements.  Later [0..CALLERS-1] contain
 203        top (GDB "prev") sites and [LENGTH-CALLEES..LENGTH-1] contain bottom
 204        (GDB "next") sites.  One is interested primarily in the PC field.  */
 205     struct call_site *call_site[1];
 206   };
 207
 208 struct call_site_stuff;
 209 extern struct call_site_chain *call_site_find_chain (struct gdbarch *gdbarch,
 210                                                      CORE_ADDR caller_pc,
 211                                                      CORE_ADDR callee_pc);
 212
 213 #endif /* dwarf2loc.h */