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