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   /* If not NULL, a buffer containing the object's value.  */
 115   const gdb_byte *valaddr;
 116
 117   /* The address of that object.  */
 118   CORE_ADDR addr;
 119
 120   /* If not NULL, a pointer to the info for the object containing
 121      the object described by this node.  */
 122   struct property_addr_info *next;
 123 };
 124
 125 /* Converts a dynamic property into a static one.  ADDR_STACK is the stack
 126    of addresses that might be needed to evaluate the property.
 127    Returns 1 if PROP could be converted and the static value is passed back
 128    into VALUE, otherwise returns 0.  */
 129
 130 int dwarf2_evaluate_property (const struct dynamic_prop *prop,
 131                               struct property_addr_info *addr_stack,
 132                               CORE_ADDR *value);
 133
 134 /* A helper for the compiler interface that compiles a single dynamic
 135    property to C code.
 136
 137    STREAM is where the C code is to be written.
 138    RESULT_NAME is the name of the generated variable.
 139    GDBARCH is the architecture to use.
 140    REGISTERS_USED is a bit-vector that is filled to note which
 141    registers are required by the generated expression.
 142    PROP is the property for which code is generated.
 143    ADDRESS is the address at which the property is considered to be
 144    evaluated.
 145    SYM the originating symbol, used for error reporting.  */
 146
 147 void dwarf2_compile_property_to_c (struct ui_file *stream,
 148                                    const char *result_name,
 149                                    struct gdbarch *gdbarch,
 150                                    unsigned char *registers_used,
 151                                    const struct dynamic_prop *prop,
 152                                    CORE_ADDR address,
 153                                    struct symbol *sym);
 154
 155 CORE_ADDR dwarf2_read_addr_index (struct dwarf2_per_cu_data *per_cu,
 156                                   unsigned int addr_index);
 157
 158 /* The symbol location baton types used by the DWARF-2 reader (i.e.
 159    SYMBOL_LOCATION_BATON for a LOC_COMPUTED symbol).  "struct
 160    dwarf2_locexpr_baton" is for a symbol with a single location
 161    expression; "struct dwarf2_loclist_baton" is for a symbol with a
 162    location list.  */
 163
 164 struct dwarf2_locexpr_baton
 165 {
 166   /* Pointer to the start of the location expression.  Valid only if SIZE is
 167      not zero.  */
 168   const gdb_byte *data;
 169
 170   /* Length of the location expression.  For optimized out expressions it is
 171      zero.  */
 172   size_t size;
 173
 174   /* The compilation unit containing the symbol whose location
 175      we're computing.  */
 176   struct dwarf2_per_cu_data *per_cu;
 177 };
 178
 179 struct dwarf2_loclist_baton
 180 {
 181   /* The initial base address for the location list, based on the compilation
 182      unit.  */
 183   CORE_ADDR base_address;
 184
 185   /* Pointer to the start of the location list.  */
 186   const gdb_byte *data;
 187
 188   /* Length of the location list.  */
 189   size_t size;
 190
 191   /* The compilation unit containing the symbol whose location
 192      we're computing.  */
 193   struct dwarf2_per_cu_data *per_cu;
 194
 195   /* Non-zero if the location list lives in .debug_loc.dwo.
 196      The format of entries in this section are different.  */
 197   unsigned char from_dwo;
 198 };
 199
 200 /* The baton used when a dynamic property is an offset to a parent
 201    type.  This can be used, for instance, then the bound of an array
 202    inside a record is determined by the value of another field inside
 203    that record.  */
 204
 205 struct dwarf2_offset_baton
 206 {
 207   /* The offset from the parent type where the value of the property
 208      is stored.  In the example provided above, this would be the offset
 209      of the field being used as the array bound.  */
 210   LONGEST offset;
 211
 212   /* The type of the object whose property is dynamic.  In the example
 213      provided above, this would the the array's index type.  */
 214   struct type *type;
 215 };
 216
 217 /* A dynamic property is either expressed as a single location expression
 218    or a location list.  If the property is an indirection, pointing to
 219    another die, keep track of the targeted type in REFERENCED_TYPE.  */
 220
 221 struct dwarf2_property_baton
 222 {
 223   /* If the property is an indirection, we need to evaluate the location
 224      in the context of the type REFERENCED_TYPE.
 225      If NULL, the location is the actual value of the property.  */
 226   struct type *referenced_type;
 227   union
 228   {
 229     /* Location expression.  */
 230     struct dwarf2_locexpr_baton locexpr;
 231
 232     /* Location list to be evaluated in the context of REFERENCED_TYPE.  */
 233     struct dwarf2_loclist_baton loclist;
 234
 235     /* The location is an offset to REFERENCED_TYPE.  */
 236     struct dwarf2_offset_baton offset_info;
 237   };
 238 };
 239
 240 extern const struct symbol_computed_ops dwarf2_locexpr_funcs;
 241 extern const struct symbol_computed_ops dwarf2_loclist_funcs;
 242
 243 extern const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs;
 244 extern const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs;
 245
 246 /* Compile a DWARF location expression to an agent expression.
 247
 248    EXPR is the agent expression we are building.
 249    LOC is the agent value we modify.
 250    ARCH is the architecture.
 251    ADDR_SIZE is the size of addresses, in bytes.
 252    OP_PTR is the start of the location expression.
 253    OP_END is one past the last byte of the location expression.
 254
 255    This will throw an exception for various kinds of errors -- for
 256    example, if the expression cannot be compiled, or if the expression
 257    is invalid.  */
 258
 259 extern void dwarf2_compile_expr_to_ax (struct agent_expr *expr,
 260                                        struct axs_value *loc,
 261                                        struct gdbarch *arch,
 262                                        unsigned int addr_size,
 263                                        const gdb_byte *op_ptr,
 264                                        const gdb_byte *op_end,
 265                                        struct dwarf2_per_cu_data *per_cu);
 266
 267 /* Determined tail calls for constructing virtual tail call frames.  */
 268
 269 struct call_site_chain
 270   {
 271     /* Initially CALLERS == CALLEES == LENGTH.  For partially ambiguous result
 272        CALLERS + CALLEES < LENGTH.  */
 273     int callers, callees, length;
 274
 275     /* Variably sized array with LENGTH elements.  Later [0..CALLERS-1] contain
 276        top (GDB "prev") sites and [LENGTH-CALLEES..LENGTH-1] contain bottom
 277        (GDB "next") sites.  One is interested primarily in the PC field.  */
 278     struct call_site *call_site[1];
 279   };
 280
 281 struct call_site_stuff;
 282 extern struct call_site_chain *call_site_find_chain (struct gdbarch *gdbarch,
 283                                                      CORE_ADDR caller_pc,
 284                                                      CORE_ADDR callee_pc);
 285
 286 /* A helper function to convert a DWARF register to an arch register.
 287    ARCH is the architecture.
 288    DWARF_REG is the register.
 289    This will throw an exception if the DWARF register cannot be
 290    translated to an architecture register.  */
 291
 292 extern int dwarf2_reg_to_regnum_or_error (struct gdbarch *arch, int dwarf_reg);
 293
 294 #endif /* dwarf2loc.h */