1 /* Get info from stack frames; convert between frames, blocks, 2 functions and pc values. 3 4 Copyright (C) 1986-2013 Free Software Foundation, Inc. 5 6 This file is part of GDB. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 20 21 #include "defs.h" 22 #include "symtab.h" 23 #include "bfd.h" 24 #include "objfiles.h" 25 #include "frame.h" 26 #include "gdbcore.h" 27 #include "value.h" 28 #include "target.h" 29 #include "inferior.h" 30 #include "annotate.h" 31 #include "regcache.h" 32 #include "gdb_assert.h" 33 #include "dummy-frame.h" 34 #include "command.h" 35 #include "gdbcmd.h" 36 #include "block.h" 37 #include "inline-frame.h" 38 #include "psymtab.h" 39 40 /* Return the innermost lexical block in execution in a specified 41 stack frame. The frame address is assumed valid. 42 43 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code 44 address we used to choose the block. We use this to find a source 45 line, to decide which macro definitions are in scope. 46 47 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's 48 PC, and may not really be a valid PC at all. For example, in the 49 caller of a function declared to never return, the code at the 50 return address will never be reached, so the call instruction may 51 be the very last instruction in the block. So the address we use 52 to choose the block is actually one byte before the return address 53 --- hopefully pointing us at the call instruction, or its delay 54 slot instruction. */ 55 56 struct block * 57 get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block) 58 { 59 CORE_ADDR pc; 60 struct block *bl; 61 int inline_count; 62 63 if (!get_frame_address_in_block_if_available (frame, &pc)) 64 return NULL; 65 66 if (addr_in_block) 67 *addr_in_block = pc; 68 69 bl = block_for_pc (pc); 70 if (bl == NULL) 71 return NULL; 72 73 inline_count = frame_inlined_callees (frame); 74 75 while (inline_count > 0) 76 { 77 if (block_inlined_p (bl)) 78 inline_count--; 79 80 bl = BLOCK_SUPERBLOCK (bl); 81 gdb_assert (bl != NULL); 82 } 83 84 return bl; 85 } 86 87 CORE_ADDR 88 get_pc_function_start (CORE_ADDR pc) 89 { 90 struct block *bl; 91 struct minimal_symbol *msymbol; 92 93 bl = block_for_pc (pc); 94 if (bl) 95 { 96 struct symbol *symbol = block_linkage_function (bl); 97 98 if (symbol) 99 { 100 bl = SYMBOL_BLOCK_VALUE (symbol); 101 return BLOCK_START (bl); 102 } 103 } 104 105 msymbol = lookup_minimal_symbol_by_pc (pc); 106 if (msymbol) 107 { 108 CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol); 109 110 if (find_pc_section (fstart)) 111 return fstart; 112 } 113 114 return 0; 115 } 116 117 /* Return the symbol for the function executing in frame FRAME. */ 118 119 struct symbol * 120 get_frame_function (struct frame_info *frame) 121 { 122 struct block *bl = get_frame_block (frame, 0); 123 124 if (bl == NULL) 125 return NULL; 126 127 while (BLOCK_FUNCTION (bl) == NULL && BLOCK_SUPERBLOCK (bl) != NULL) 128 bl = BLOCK_SUPERBLOCK (bl); 129 130 return BLOCK_FUNCTION (bl); 131 } 132 133 134 /* Return the function containing pc value PC in section SECTION. 135 Returns 0 if function is not known. */ 136 137 struct symbol * 138 find_pc_sect_function (CORE_ADDR pc, struct obj_section *section) 139 { 140 struct block *b = block_for_pc_sect (pc, section); 141 142 if (b == 0) 143 return 0; 144 return block_linkage_function (b); 145 } 146 147 /* Return the function containing pc value PC. 148 Returns 0 if function is not known. 149 Backward compatibility, no section */ 150 151 struct symbol * 152 find_pc_function (CORE_ADDR pc) 153 { 154 return find_pc_sect_function (pc, find_pc_mapped_section (pc)); 155 } 156 157 /* These variables are used to cache the most recent result 158 of find_pc_partial_function. */ 159 160 static CORE_ADDR cache_pc_function_low = 0; 161 static CORE_ADDR cache_pc_function_high = 0; 162 static const char *cache_pc_function_name = 0; 163 static struct obj_section *cache_pc_function_section = NULL; 164 static int cache_pc_function_is_gnu_ifunc = 0; 165 166 /* Clear cache, e.g. when symbol table is discarded. */ 167 168 void 169 clear_pc_function_cache (void) 170 { 171 cache_pc_function_low = 0; 172 cache_pc_function_high = 0; 173 cache_pc_function_name = (char *) 0; 174 cache_pc_function_section = NULL; 175 cache_pc_function_is_gnu_ifunc = 0; 176 } 177 178 /* Finds the "function" (text symbol) that is smaller than PC but 179 greatest of all of the potential text symbols in SECTION. Sets 180 *NAME and/or *ADDRESS conditionally if that pointer is non-null. 181 If ENDADDR is non-null, then set *ENDADDR to be the end of the 182 function (exclusive), but passing ENDADDR as non-null means that 183 the function might cause symbols to be read. If IS_GNU_IFUNC_P is provided 184 *IS_GNU_IFUNC_P is set to 1 on return if the function is STT_GNU_IFUNC. 185 This function either succeeds or fails (not halfway succeeds). If it 186 succeeds, it sets *NAME, *ADDRESS, and *ENDADDR to real information and 187 returns 1. If it fails, it sets *NAME, *ADDRESS, *ENDADDR and 188 *IS_GNU_IFUNC_P to zero and returns 0. */ 189 190 /* Backward compatibility, no section argument. */ 191 192 int 193 find_pc_partial_function_gnu_ifunc (CORE_ADDR pc, const char **name, 194 CORE_ADDR *address, CORE_ADDR *endaddr, 195 int *is_gnu_ifunc_p) 196 { 197 struct obj_section *section; 198 struct symbol *f; 199 struct minimal_symbol *msymbol; 200 struct symtab *symtab = NULL; 201 struct objfile *objfile; 202 int i; 203 CORE_ADDR mapped_pc; 204 205 /* To ensure that the symbol returned belongs to the correct setion 206 (and that the last [random] symbol from the previous section 207 isn't returned) try to find the section containing PC. First try 208 the overlay code (which by default returns NULL); and second try 209 the normal section code (which almost always succeeds). */ 210 section = find_pc_overlay (pc); 211 if (section == NULL) 212 section = find_pc_section (pc); 213 214 mapped_pc = overlay_mapped_address (pc, section); 215 216 if (mapped_pc >= cache_pc_function_low 217 && mapped_pc < cache_pc_function_high 218 && section == cache_pc_function_section) 219 goto return_cached_value; 220 221 msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section); 222 ALL_OBJFILES (objfile) 223 { 224 if (objfile->sf) 225 symtab = objfile->sf->qf->find_pc_sect_symtab (objfile, msymbol, 226 mapped_pc, section, 0); 227 if (symtab) 228 break; 229 } 230 231 if (symtab) 232 { 233 /* Checking whether the msymbol has a larger value is for the 234 "pathological" case mentioned in print_frame_info. */ 235 f = find_pc_sect_function (mapped_pc, section); 236 if (f != NULL 237 && (msymbol == NULL 238 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f)) 239 >= SYMBOL_VALUE_ADDRESS (msymbol)))) 240 { 241 cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f)); 242 cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f)); 243 cache_pc_function_name = SYMBOL_LINKAGE_NAME (f); 244 cache_pc_function_section = section; 245 cache_pc_function_is_gnu_ifunc = TYPE_GNU_IFUNC (SYMBOL_TYPE (f)); 246 goto return_cached_value; 247 } 248 } 249 250 /* Not in the normal symbol tables, see if the pc is in a known 251 section. If it's not, then give up. This ensures that anything 252 beyond the end of the text seg doesn't appear to be part of the 253 last function in the text segment. */ 254 255 if (!section) 256 msymbol = NULL; 257 258 /* Must be in the minimal symbol table. */ 259 if (msymbol == NULL) 260 { 261 /* No available symbol. */ 262 if (name != NULL) 263 *name = 0; 264 if (address != NULL) 265 *address = 0; 266 if (endaddr != NULL) 267 *endaddr = 0; 268 if (is_gnu_ifunc_p != NULL) 269 *is_gnu_ifunc_p = 0; 270 return 0; 271 } 272 273 cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol); 274 cache_pc_function_name = SYMBOL_LINKAGE_NAME (msymbol); 275 cache_pc_function_section = section; 276 cache_pc_function_is_gnu_ifunc = MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc; 277 278 /* If the minimal symbol has a size, use it for the cache. 279 Otherwise use the lesser of the next minimal symbol in the same 280 section, or the end of the section, as the end of the 281 function. */ 282 283 if (MSYMBOL_SIZE (msymbol) != 0) 284 cache_pc_function_high = cache_pc_function_low + MSYMBOL_SIZE (msymbol); 285 else 286 { 287 /* Step over other symbols at this same address, and symbols in 288 other sections, to find the next symbol in this section with 289 a different address. */ 290 291 for (i = 1; SYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++) 292 { 293 if (SYMBOL_VALUE_ADDRESS (msymbol + i) 294 != SYMBOL_VALUE_ADDRESS (msymbol) 295 && SYMBOL_OBJ_SECTION (msymbol + i) 296 == SYMBOL_OBJ_SECTION (msymbol)) 297 break; 298 } 299 300 if (SYMBOL_LINKAGE_NAME (msymbol + i) != NULL 301 && SYMBOL_VALUE_ADDRESS (msymbol + i) 302 < obj_section_endaddr (section)) 303 cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i); 304 else 305 /* We got the start address from the last msymbol in the objfile. 306 So the end address is the end of the section. */ 307 cache_pc_function_high = obj_section_endaddr (section); 308 } 309 310 return_cached_value: 311 312 if (address) 313 { 314 if (pc_in_unmapped_range (pc, section)) 315 *address = overlay_unmapped_address (cache_pc_function_low, section); 316 else 317 *address = cache_pc_function_low; 318 } 319 320 if (name) 321 *name = cache_pc_function_name; 322 323 if (endaddr) 324 { 325 if (pc_in_unmapped_range (pc, section)) 326 { 327 /* Because the high address is actually beyond the end of 328 the function (and therefore possibly beyond the end of 329 the overlay), we must actually convert (high - 1) and 330 then add one to that. */ 331 332 *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1, 333 section); 334 } 335 else 336 *endaddr = cache_pc_function_high; 337 } 338 339 if (is_gnu_ifunc_p) 340 *is_gnu_ifunc_p = cache_pc_function_is_gnu_ifunc; 341 342 return 1; 343 } 344 345 /* See find_pc_partial_function_gnu_ifunc, only the IS_GNU_IFUNC_P parameter 346 is omitted here for backward API compatibility. */ 347 348 int 349 find_pc_partial_function (CORE_ADDR pc, const char **name, CORE_ADDR *address, 350 CORE_ADDR *endaddr) 351 { 352 return find_pc_partial_function_gnu_ifunc (pc, name, address, endaddr, NULL); 353 } 354 355 /* Return the innermost stack frame that is executing inside of BLOCK and is 356 at least as old as the selected frame. Return NULL if there is no 357 such frame. If BLOCK is NULL, just return NULL. */ 358 359 struct frame_info * 360 block_innermost_frame (const struct block *block) 361 { 362 struct frame_info *frame; 363 364 if (block == NULL) 365 return NULL; 366 367 frame = get_selected_frame_if_set (); 368 if (frame == NULL) 369 frame = get_current_frame (); 370 while (frame != NULL) 371 { 372 struct block *frame_block = get_frame_block (frame, NULL); 373 if (frame_block != NULL && contained_in (frame_block, block)) 374 return frame; 375 376 frame = get_prev_frame (frame); 377 } 378 379 return NULL; 380 } 381