| 1 | /* DWARF 2 location expression support for GDB. |
| 2 | |
| 3 | Copyright (C) 2003-2020 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 "dwarf2/expr.h" |
| 24 | |
| 25 | struct symbol_computed_ops; |
| 26 | struct dwarf2_per_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 | /* Find a particular location expression from a location list. */ |
| 39 | const gdb_byte *dwarf2_find_location_expression |
| 40 | (struct dwarf2_loclist_baton *baton, |
| 41 | size_t *locexpr_length, |
| 42 | CORE_ADDR pc); |
| 43 | |
| 44 | /* Find the frame base information for FRAMEFUNC at PC. START is an |
| 45 | out parameter which is set to point to the DWARF expression to |
| 46 | compute. LENGTH is an out parameter which is set to the length of |
| 47 | the DWARF expression. This throws an exception on error or if an |
| 48 | expression is not found; the returned length will never be |
| 49 | zero. */ |
| 50 | |
| 51 | extern void func_get_frame_base_dwarf_block (struct symbol *framefunc, |
| 52 | CORE_ADDR pc, |
| 53 | const gdb_byte **start, |
| 54 | size_t *length); |
| 55 | |
| 56 | /* Evaluate a location description, starting at DATA and with length |
| 57 | SIZE, to find the current location of variable of TYPE in the context |
| 58 | of FRAME. */ |
| 59 | |
| 60 | struct value *dwarf2_evaluate_loc_desc (struct type *type, |
| 61 | struct frame_info *frame, |
| 62 | const gdb_byte *data, |
| 63 | size_t size, |
| 64 | dwarf2_per_cu_data *per_cu, |
| 65 | dwarf2_per_objfile *per_objfile); |
| 66 | |
| 67 | /* A chain of addresses that might be needed to resolve a dynamic |
| 68 | property. */ |
| 69 | |
| 70 | struct property_addr_info |
| 71 | { |
| 72 | /* The type of the object whose dynamic properties, if any, are |
| 73 | being resolved. */ |
| 74 | struct type *type; |
| 75 | |
| 76 | /* If not NULL, a buffer containing the object's value. */ |
| 77 | gdb::array_view<const gdb_byte> valaddr; |
| 78 | |
| 79 | /* The address of that object. */ |
| 80 | CORE_ADDR addr; |
| 81 | |
| 82 | /* If not NULL, a pointer to the info for the object containing |
| 83 | the object described by this node. */ |
| 84 | struct property_addr_info *next; |
| 85 | }; |
| 86 | |
| 87 | /* Converts a dynamic property into a static one. FRAME is the frame in which |
| 88 | the property is evaluated; if NULL, the selected frame (if any) is used |
| 89 | instead. |
| 90 | |
| 91 | ADDR_STACK is the stack of addresses that might be needed to evaluate the |
| 92 | property. When evaluating a property that is not related to a type, it can |
| 93 | be NULL. |
| 94 | |
| 95 | Returns true if PROP could be converted and the static value is passed |
| 96 | back into VALUE, otherwise returns false. |
| 97 | |
| 98 | If PUSH_INITIAL_VALUE is true, then the top value of ADDR_STACK |
| 99 | will be pushed before evaluating a location expression. */ |
| 100 | |
| 101 | bool dwarf2_evaluate_property (const struct dynamic_prop *prop, |
| 102 | struct frame_info *frame, |
| 103 | const struct property_addr_info *addr_stack, |
| 104 | CORE_ADDR *value, |
| 105 | bool push_initial_value = false); |
| 106 | |
| 107 | /* A helper for the compiler interface that compiles a single dynamic |
| 108 | property to C code. |
| 109 | |
| 110 | STREAM is where the C code is to be written. |
| 111 | RESULT_NAME is the name of the generated variable. |
| 112 | GDBARCH is the architecture to use. |
| 113 | REGISTERS_USED is a bit-vector that is filled to note which |
| 114 | registers are required by the generated expression. |
| 115 | PROP is the property for which code is generated. |
| 116 | ADDRESS is the address at which the property is considered to be |
| 117 | evaluated. |
| 118 | SYM the originating symbol, used for error reporting. */ |
| 119 | |
| 120 | void dwarf2_compile_property_to_c (string_file *stream, |
| 121 | const char *result_name, |
| 122 | struct gdbarch *gdbarch, |
| 123 | unsigned char *registers_used, |
| 124 | const struct dynamic_prop *prop, |
| 125 | CORE_ADDR address, |
| 126 | struct symbol *sym); |
| 127 | |
| 128 | /* The symbol location baton types used by the DWARF-2 reader (i.e. |
| 129 | SYMBOL_LOCATION_BATON for a LOC_COMPUTED symbol). "struct |
| 130 | dwarf2_locexpr_baton" is for a symbol with a single location |
| 131 | expression; "struct dwarf2_loclist_baton" is for a symbol with a |
| 132 | location list. */ |
| 133 | |
| 134 | struct dwarf2_locexpr_baton |
| 135 | { |
| 136 | /* Pointer to the start of the location expression. Valid only if SIZE is |
| 137 | not zero. */ |
| 138 | const gdb_byte *data; |
| 139 | |
| 140 | /* Length of the location expression. For optimized out expressions it is |
| 141 | zero. */ |
| 142 | size_t size; |
| 143 | |
| 144 | /* When true this location expression is a reference and actually |
| 145 | describes the address at which the value of the attribute can be |
| 146 | found. When false the expression provides the value of the attribute |
| 147 | directly. */ |
| 148 | bool is_reference; |
| 149 | |
| 150 | /* The objfile that was used when creating this. */ |
| 151 | dwarf2_per_objfile *per_objfile; |
| 152 | |
| 153 | /* The compilation unit containing the symbol whose location |
| 154 | we're computing. */ |
| 155 | struct dwarf2_per_cu_data *per_cu; |
| 156 | }; |
| 157 | |
| 158 | struct dwarf2_loclist_baton |
| 159 | { |
| 160 | /* The initial base address for the location list, based on the compilation |
| 161 | unit. */ |
| 162 | CORE_ADDR base_address; |
| 163 | |
| 164 | /* Pointer to the start of the location list. */ |
| 165 | const gdb_byte *data; |
| 166 | |
| 167 | /* Length of the location list. */ |
| 168 | size_t size; |
| 169 | |
| 170 | /* The objfile that was used when creating this. */ |
| 171 | dwarf2_per_objfile *per_objfile; |
| 172 | |
| 173 | /* The compilation unit containing the symbol whose location |
| 174 | we're computing. */ |
| 175 | struct dwarf2_per_cu_data *per_cu; |
| 176 | |
| 177 | /* Non-zero if the location list lives in .debug_loc.dwo. |
| 178 | The format of entries in this section are different. */ |
| 179 | unsigned char from_dwo; |
| 180 | }; |
| 181 | |
| 182 | /* The baton used when a dynamic property is an offset to a parent |
| 183 | type. This can be used, for instance, then the bound of an array |
| 184 | inside a record is determined by the value of another field inside |
| 185 | that record. */ |
| 186 | |
| 187 | struct dwarf2_offset_baton |
| 188 | { |
| 189 | /* The offset from the parent type where the value of the property |
| 190 | is stored. In the example provided above, this would be the offset |
| 191 | of the field being used as the array bound. */ |
| 192 | LONGEST offset; |
| 193 | |
| 194 | /* The type of the object whose property is dynamic. In the example |
| 195 | provided above, this would the array's index type. */ |
| 196 | struct type *type; |
| 197 | }; |
| 198 | |
| 199 | /* A dynamic property is either expressed as a single location expression |
| 200 | or a location list. If the property is an indirection, pointing to |
| 201 | another die, keep track of the targeted type in PROPERTY_TYPE. |
| 202 | Alternatively, if the property location gives the property value |
| 203 | directly then it will have PROPERTY_TYPE. */ |
| 204 | |
| 205 | struct dwarf2_property_baton |
| 206 | { |
| 207 | /* If the property is an indirection, we need to evaluate the location |
| 208 | in the context of the type PROPERTY_TYPE. If the property is supplied |
| 209 | by value then it will be of PROPERTY_TYPE. This field should never be |
| 210 | NULL. */ |
| 211 | struct type *property_type; |
| 212 | union |
| 213 | { |
| 214 | /* Location expression either evaluated in the context of |
| 215 | PROPERTY_TYPE, or a value of type PROPERTY_TYPE. */ |
| 216 | struct dwarf2_locexpr_baton locexpr; |
| 217 | |
| 218 | /* Location list to be evaluated in the context of PROPERTY_TYPE. */ |
| 219 | struct dwarf2_loclist_baton loclist; |
| 220 | |
| 221 | /* The location is an offset to PROPERTY_TYPE. */ |
| 222 | struct dwarf2_offset_baton offset_info; |
| 223 | }; |
| 224 | }; |
| 225 | |
| 226 | extern const struct symbol_computed_ops dwarf2_locexpr_funcs; |
| 227 | extern const struct symbol_computed_ops dwarf2_loclist_funcs; |
| 228 | |
| 229 | extern const struct symbol_block_ops dwarf2_block_frame_base_locexpr_funcs; |
| 230 | extern const struct symbol_block_ops dwarf2_block_frame_base_loclist_funcs; |
| 231 | |
| 232 | /* Determined tail calls for constructing virtual tail call frames. */ |
| 233 | |
| 234 | struct call_site_chain |
| 235 | { |
| 236 | /* Initially CALLERS == CALLEES == LENGTH. For partially ambiguous result |
| 237 | CALLERS + CALLEES < LENGTH. */ |
| 238 | int callers, callees, length; |
| 239 | |
| 240 | /* Variably sized array with LENGTH elements. Later [0..CALLERS-1] contain |
| 241 | top (GDB "prev") sites and [LENGTH-CALLEES..LENGTH-1] contain bottom |
| 242 | (GDB "next") sites. One is interested primarily in the PC field. */ |
| 243 | struct call_site *call_site[1]; |
| 244 | }; |
| 245 | |
| 246 | struct call_site_stuff; |
| 247 | extern gdb::unique_xmalloc_ptr<call_site_chain> call_site_find_chain |
| 248 | (struct gdbarch *gdbarch, CORE_ADDR caller_pc, CORE_ADDR callee_pc); |
| 249 | |
| 250 | /* A helper function to convert a DWARF register to an arch register. |
| 251 | ARCH is the architecture. |
| 252 | DWARF_REG is the register. |
| 253 | If DWARF_REG is bad then a complaint is issued and -1 is returned. |
| 254 | Note: Some targets get this wrong. */ |
| 255 | |
| 256 | extern int dwarf_reg_to_regnum (struct gdbarch *arch, int dwarf_reg); |
| 257 | |
| 258 | /* A wrapper on dwarf_reg_to_regnum to throw an exception if the |
| 259 | DWARF register cannot be translated to an architecture register. |
| 260 | This takes a ULONGEST instead of an int because some callers actually have |
| 261 | a ULONGEST. Negative values passed as ints will still be flagged as |
| 262 | invalid. */ |
| 263 | |
| 264 | extern int dwarf_reg_to_regnum_or_error (struct gdbarch *arch, |
| 265 | ULONGEST dwarf_reg); |
| 266 | |
| 267 | #endif /* dwarf2loc.h */ |