gdb/dwarf2loc.h

   1 /* DWARF 2 location expression support for GDB.
   2
   3    Copyright (C) 2003-2015 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 /* A chain of addresses that might be needed to resolve a dynamic
 106    property.  */
 107
 108 struct property_addr_info
 109 {
 110   /* The type of the object whose dynamic properties, if any, are
 111      being resolved.  */
 112   struct type *type;
 113
 114   /* The address of that object.  */
 115   CORE_ADDR addr;
 116
 117   /* If not NULL, a pointer to the info for the object containing
 118      the object described by this node.  */
 119   struct property_addr_info *next;
 120 };
 121
 122 /* Converts a dynamic property into a static one.  ADDR_STACK is the stack
 123    of addresses that might be needed to evaluate the property.
 124    Returns 1 if PROP could be converted and the static value is passed back
 125    into VALUE, otherwise returns 0.  */
 126
 127 int dwarf2_evaluate_property (const struct dynamic_prop *prop,
 128                               struct property_addr_info *addr_stack,
 129                               CORE_ADDR *value);
 130
 131 /* A helper for the compiler interface that compiles a single dynamic
 132    property to C code.
 133
 134    STREAM is where the C code is to be written.
 135    RESULT_NAME is the name of the generated variable.
 136    GDBARCH is the architecture to use.
 137    REGISTERS_USED is a bit-vector that is filled to note which
 138    registers are required by the generated expression.
 139    PROP is the property for which code is generated.
 140    ADDRESS is the address at which the property is considered to be
 141    evaluated.
 142    SYM the originating symbol, used for error reporting.  */
 143
 144 void dwarf2_compile_property_to_c (struct ui_file *stream,
 145                                    const char *result_name,
 146                                    struct gdbarch *gdbarch,
 147                                    unsigned char *registers_used,
 148                                    const struct dynamic_prop *prop,
 149                                    CORE_ADDR address,
 150                                    struct symbol *sym);
 151
 152 CORE_ADDR dwarf2_read_addr_index (struct dwarf2_per_cu_data *per_cu,
 153                                   unsigned int addr_index);
 154
 155 /* The symbol location baton types used by the DWARF-2 reader (i.e.
 156    SYMBOL_LOCATION_BATON for a LOC_COMPUTED symbol).  "struct
 157    dwarf2_locexpr_baton" is for a symbol with a single location
 158    expression; "struct dwarf2_loclist_baton" is for a symbol with a
 159    location list.  */
 160
 161 struct dwarf2_locexpr_baton
 162 {
 163   /* Pointer to the start of the location expression.  Valid only if SIZE is
 164      not zero.  */
 165   const gdb_byte *data;
 166
 167   /* Length of the location expression.  For optimized out expressions it is
 168      zero.  */
 169   size_t size;
 170
 171   /* The compilation unit containing the symbol whose location
 172      we're computing.  */
 173   struct dwarf2_per_cu_data *per_cu;
 174 };
 175
 176 struct dwarf2_loclist_baton
 177 {
 178   /* The initial base address for the location list, based on the compilation
 179      unit.  */
 180   CORE_ADDR base_address;
 181
 182   /* Pointer to the start of the location list.  */
 183   const gdb_byte *data;
 184
 185   /* Length of the location list.  */
 186   size_t size;
 187
 188   /* The compilation unit containing the symbol whose location
 189      we're computing.  */
 190   struct dwarf2_per_cu_data *per_cu;
 191
 192   /* Non-zero if the location list lives in .debug_loc.dwo.
 193      The format of entries in this section are different.  */
 194   unsigned char from_dwo;
 195 };
 196
 197 /* The baton used when a dynamic property is an offset to a parent
 198    type.  This can be used, for instance, then the bound of an array
 199    inside a record is determined by the value of another field inside
 200    that record.  */
 201
 202 struct dwarf2_offset_baton
 203 {
 204   /* The offset from the parent type where the value of the property
 205      is stored.  In the example provided above, this would be the offset
 206      of the field being used as the array bound.  */
 207   LONGEST offset;
 208
 209   /* The type of the object whose property is dynamic.  In the example
 210      provided above, this would the the array's index type.  */
 211   struct type *type;
 212 };
 213
 214 /* A dynamic property is either expressed as a single location expression
 215    or a location list.  If the property is an indirection, pointing to
 216    another die, keep track of the targeted type in REFERENCED_TYPE.  */
 217
 218 struct dwarf2_property_baton
 219 {
 220   /* If the property is an indirection, we need to evaluate the location
 221      in the context of the type REFERENCED_TYPE.
 222      If NULL, the location is the actual value of the property.  */
 223   struct type *referenced_type;
 224   union
 225   {
 226     /* Location expression.  */
 227     struct dwarf2_locexpr_baton locexpr;
 228
 229     /* Location list to be evaluated in the context of REFERENCED_TYPE.  */
 230     struct dwarf2_loclist_baton loclist;
 231
 232     /* The location is an offset to REFERENCED_TYPE.  */
 233     struct dwarf2_offset_baton offset_info;
 234   };
 235 };
 236
 237 extern const struct symbol_computed_ops dwarf2_locexpr_funcs;
 238 extern const struct symbol_computed_ops dwarf2_loclist_funcs;
 239
 240 extern const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs;
 241 extern const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs;
 242
 243 /* Compile a DWARF location expression to an agent expression.
 244
 245    EXPR is the agent expression we are building.
 246    LOC is the agent value we modify.
 247    ARCH is the architecture.
 248    ADDR_SIZE is the size of addresses, in bytes.
 249    OP_PTR is the start of the location expression.
 250    OP_END is one past the last byte of the location expression.
 251
 252    This will throw an exception for various kinds of errors -- for
 253    example, if the expression cannot be compiled, or if the expression
 254    is invalid.  */
 255
 256 extern void dwarf2_compile_expr_to_ax (struct agent_expr *expr,
 257                                        struct axs_value *loc,
 258                                        struct gdbarch *arch,
 259                                        unsigned int addr_size,
 260                                        const gdb_byte *op_ptr,
 261                                        const gdb_byte *op_end,
 262                                        struct dwarf2_per_cu_data *per_cu);
 263
 264 /* Determined tail calls for constructing virtual tail call frames.  */
 265
 266 struct call_site_chain
 267   {
 268     /* Initially CALLERS == CALLEES == LENGTH.  For partially ambiguous result
 269        CALLERS + CALLEES < LENGTH.  */
 270     int callers, callees, length;
 271
 272     /* Variably sized array with LENGTH elements.  Later [0..CALLERS-1] contain
 273        top (GDB "prev") sites and [LENGTH-CALLEES..LENGTH-1] contain bottom
 274        (GDB "next") sites.  One is interested primarily in the PC field.  */
 275     struct call_site *call_site[1];
 276   };
 277
 278 struct call_site_stuff;
 279 extern struct call_site_chain *call_site_find_chain (struct gdbarch *gdbarch,
 280                                                      CORE_ADDR caller_pc,
 281                                                      CORE_ADDR callee_pc);
 282
 283 /* A helper function to convert a DWARF register to an arch register.
 284    ARCH is the architecture.
 285    DWARF_REG is the register.
 286    This will throw an exception if the DWARF register cannot be
 287    translated to an architecture register.  */
 288
 289 extern int dwarf2_reg_to_regnum_or_error (struct gdbarch *arch, int dwarf_reg);
 290
 291 #endif /* dwarf2loc.h */