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