gdb/dwarf2loc.h

   1 /* DWARF 2 location expression support for GDB.
   2
   3    Copyright (C) 2003-2016 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.  FRAME is the frame in which
 126    the property is evaluated; if NULL, the selected frame (if any) is used
 127    instead.
 128
 129    ADDR_STACK is the stack of addresses that might be needed to evaluate the
 130    property. When evaluating a property that is not related to a type, it can
 131    be NULL.
 132
 133    Returns 1 if PROP could be converted and the static value is passed back
 134    into VALUE, otherwise returns 0.  */
 135
 136 int dwarf2_evaluate_property (const struct dynamic_prop *prop,
 137                               struct frame_info *frame,
 138                               struct property_addr_info *addr_stack,
 139                               CORE_ADDR *value);
 140
 141 /* A helper for the compiler interface that compiles a single dynamic
 142    property to C code.
 143
 144    STREAM is where the C code is to be written.
 145    RESULT_NAME is the name of the generated variable.
 146    GDBARCH is the architecture to use.
 147    REGISTERS_USED is a bit-vector that is filled to note which
 148    registers are required by the generated expression.
 149    PROP is the property for which code is generated.
 150    ADDRESS is the address at which the property is considered to be
 151    evaluated.
 152    SYM the originating symbol, used for error reporting.  */
 153
 154 void dwarf2_compile_property_to_c (struct ui_file *stream,
 155                                    const char *result_name,
 156                                    struct gdbarch *gdbarch,
 157                                    unsigned char *registers_used,
 158                                    const struct dynamic_prop *prop,
 159                                    CORE_ADDR address,
 160                                    struct symbol *sym);
 161
 162 CORE_ADDR dwarf2_read_addr_index (struct dwarf2_per_cu_data *per_cu,
 163                                   unsigned int addr_index);
 164
 165 /* The symbol location baton types used by the DWARF-2 reader (i.e.
 166    SYMBOL_LOCATION_BATON for a LOC_COMPUTED symbol).  "struct
 167    dwarf2_locexpr_baton" is for a symbol with a single location
 168    expression; "struct dwarf2_loclist_baton" is for a symbol with a
 169    location list.  */
 170
 171 struct dwarf2_locexpr_baton
 172 {
 173   /* Pointer to the start of the location expression.  Valid only if SIZE is
 174      not zero.  */
 175   const gdb_byte *data;
 176
 177   /* Length of the location expression.  For optimized out expressions it is
 178      zero.  */
 179   size_t size;
 180
 181   /* The compilation unit containing the symbol whose location
 182      we're computing.  */
 183   struct dwarf2_per_cu_data *per_cu;
 184 };
 185
 186 struct dwarf2_loclist_baton
 187 {
 188   /* The initial base address for the location list, based on the compilation
 189      unit.  */
 190   CORE_ADDR base_address;
 191
 192   /* Pointer to the start of the location list.  */
 193   const gdb_byte *data;
 194
 195   /* Length of the location list.  */
 196   size_t size;
 197
 198   /* The compilation unit containing the symbol whose location
 199      we're computing.  */
 200   struct dwarf2_per_cu_data *per_cu;
 201
 202   /* Non-zero if the location list lives in .debug_loc.dwo.
 203      The format of entries in this section are different.  */
 204   unsigned char from_dwo;
 205 };
 206
 207 /* The baton used when a dynamic property is an offset to a parent
 208    type.  This can be used, for instance, then the bound of an array
 209    inside a record is determined by the value of another field inside
 210    that record.  */
 211
 212 struct dwarf2_offset_baton
 213 {
 214   /* The offset from the parent type where the value of the property
 215      is stored.  In the example provided above, this would be the offset
 216      of the field being used as the array bound.  */
 217   LONGEST offset;
 218
 219   /* The type of the object whose property is dynamic.  In the example
 220      provided above, this would the the array's index type.  */
 221   struct type *type;
 222 };
 223
 224 /* A dynamic property is either expressed as a single location expression
 225    or a location list.  If the property is an indirection, pointing to
 226    another die, keep track of the targeted type in REFERENCED_TYPE.  */
 227
 228 struct dwarf2_property_baton
 229 {
 230   /* If the property is an indirection, we need to evaluate the location
 231      in the context of the type REFERENCED_TYPE.
 232      If NULL, the location is the actual value of the property.  */
 233   struct type *referenced_type;
 234   union
 235   {
 236     /* Location expression.  */
 237     struct dwarf2_locexpr_baton locexpr;
 238
 239     /* Location list to be evaluated in the context of REFERENCED_TYPE.  */
 240     struct dwarf2_loclist_baton loclist;
 241
 242     /* The location is an offset to REFERENCED_TYPE.  */
 243     struct dwarf2_offset_baton offset_info;
 244   };
 245 };
 246
 247 extern const struct symbol_computed_ops dwarf2_locexpr_funcs;
 248 extern const struct symbol_computed_ops dwarf2_loclist_funcs;
 249
 250 extern const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs;
 251 extern const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs;
 252
 253 /* Compile a DWARF location expression to an agent expression.
 254
 255    EXPR is the agent expression we are building.
 256    LOC is the agent value we modify.
 257    ARCH is the architecture.
 258    ADDR_SIZE is the size of addresses, in bytes.
 259    OP_PTR is the start of the location expression.
 260    OP_END is one past the last byte of the location expression.
 261
 262    This will throw an exception for various kinds of errors -- for
 263    example, if the expression cannot be compiled, or if the expression
 264    is invalid.  */
 265
 266 extern void dwarf2_compile_expr_to_ax (struct agent_expr *expr,
 267                                        struct axs_value *loc,
 268                                        struct gdbarch *arch,
 269                                        unsigned int addr_size,
 270                                        const gdb_byte *op_ptr,
 271                                        const gdb_byte *op_end,
 272                                        struct dwarf2_per_cu_data *per_cu);
 273
 274 /* Determined tail calls for constructing virtual tail call frames.  */
 275
 276 struct call_site_chain
 277   {
 278     /* Initially CALLERS == CALLEES == LENGTH.  For partially ambiguous result
 279        CALLERS + CALLEES < LENGTH.  */
 280     int callers, callees, length;
 281
 282     /* Variably sized array with LENGTH elements.  Later [0..CALLERS-1] contain
 283        top (GDB "prev") sites and [LENGTH-CALLEES..LENGTH-1] contain bottom
 284        (GDB "next") sites.  One is interested primarily in the PC field.  */
 285     struct call_site *call_site[1];
 286   };
 287
 288 struct call_site_stuff;
 289 extern struct call_site_chain *call_site_find_chain (struct gdbarch *gdbarch,
 290                                                      CORE_ADDR caller_pc,
 291                                                      CORE_ADDR callee_pc);
 292
 293 /* A helper function to convert a DWARF register to an arch register.
 294    ARCH is the architecture.
 295    DWARF_REG is the register.
 296    If DWARF_REG is bad then a complaint is issued and -1 is returned.
 297    Note: Some targets get this wrong.  */
 298
 299 extern int dwarf_reg_to_regnum (struct gdbarch *arch, int dwarf_reg);
 300
 301 /* A wrapper on dwarf_reg_to_regnum to throw an exception if the
 302    DWARF register cannot be translated to an architecture register.
 303    This takes a ULONGEST instead of an int because some callers actually have
 304    a ULONGEST.  Negative values passed as ints will still be flagged as
 305    invalid.  */
 306
 307 extern int dwarf_reg_to_regnum_or_error (struct gdbarch *arch,
 308                                          ULONGEST dwarf_reg);
 309
 310 #endif /* dwarf2loc.h */