1 /* Get info from stack frames; convert between frames, blocks, 2 functions and pc values. 3 4 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 5 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2007, 2008, 2009, 6 2010, 2011 Free Software Foundation, Inc. 7 8 This file is part of GDB. 9 10 This program is free software; you can redistribute it and/or modify 11 it under the terms of the GNU General Public License as published by 12 the Free Software Foundation; either version 3 of the License, or 13 (at your option) any later version. 14 15 This program is distributed in the hope that it will be useful, 16 but WITHOUT ANY WARRANTY; without even the implied warranty of 17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 GNU General Public License for more details. 19 20 You should have received a copy of the GNU General Public License 21 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 22 23 #include "defs.h" 24 #include "symtab.h" 25 #include "bfd.h" 26 #include "objfiles.h" 27 #include "frame.h" 28 #include "gdbcore.h" 29 #include "value.h" 30 #include "target.h" 31 #include "inferior.h" 32 #include "annotate.h" 33 #include "regcache.h" 34 #include "gdb_assert.h" 35 #include "dummy-frame.h" 36 #include "command.h" 37 #include "gdbcmd.h" 38 #include "block.h" 39 #include "inline-frame.h" 40 #include "psymtab.h" 41 42 /* Return the innermost lexical block in execution in a specified 43 stack frame. The frame address is assumed valid. 44 45 If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code 46 address we used to choose the block. We use this to find a source 47 line, to decide which macro definitions are in scope. 48 49 The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's 50 PC, and may not really be a valid PC at all. For example, in the 51 caller of a function declared to never return, the code at the 52 return address will never be reached, so the call instruction may 53 be the very last instruction in the block. So the address we use 54 to choose the block is actually one byte before the return address 55 --- hopefully pointing us at the call instruction, or its delay 56 slot instruction. */ 57 58 struct block * 59 get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block) 60 { 61 CORE_ADDR pc; 62 struct block *bl; 63 int inline_count; 64 65 if (!get_frame_address_in_block_if_available (frame, &pc)) 66 return NULL; 67 68 if (addr_in_block) 69 *addr_in_block = pc; 70 71 bl = block_for_pc (pc); 72 if (bl == NULL) 73 return NULL; 74 75 inline_count = frame_inlined_callees (frame); 76 77 while (inline_count > 0) 78 { 79 if (block_inlined_p (bl)) 80 inline_count--; 81 82 bl = BLOCK_SUPERBLOCK (bl); 83 gdb_assert (bl != NULL); 84 } 85 86 return bl; 87 } 88 89 CORE_ADDR 90 get_pc_function_start (CORE_ADDR pc) 91 { 92 struct block *bl; 93 struct minimal_symbol *msymbol; 94 95 bl = block_for_pc (pc); 96 if (bl) 97 { 98 struct symbol *symbol = block_linkage_function (bl); 99 100 if (symbol) 101 { 102 bl = SYMBOL_BLOCK_VALUE (symbol); 103 return BLOCK_START (bl); 104 } 105 } 106 107 msymbol = lookup_minimal_symbol_by_pc (pc); 108 if (msymbol) 109 { 110 CORE_ADDR fstart = SYMBOL_VALUE_ADDRESS (msymbol); 111 112 if (find_pc_section (fstart)) 113 return fstart; 114 } 115 116 return 0; 117 } 118 119 /* Return the symbol for the function executing in frame FRAME. */ 120 121 struct symbol * 122 get_frame_function (struct frame_info *frame) 123 { 124 struct block *bl = get_frame_block (frame, 0); 125 126 if (bl == NULL) 127 return NULL; 128 129 while (BLOCK_FUNCTION (bl) == NULL && BLOCK_SUPERBLOCK (bl) != NULL) 130 bl = BLOCK_SUPERBLOCK (bl); 131 132 return BLOCK_FUNCTION (bl); 133 } 134 135 136 /* Return the function containing pc value PC in section SECTION. 137 Returns 0 if function is not known. */ 138 139 struct symbol * 140 find_pc_sect_function (CORE_ADDR pc, struct obj_section *section) 141 { 142 struct block *b = block_for_pc_sect (pc, section); 143 144 if (b == 0) 145 return 0; 146 return block_linkage_function (b); 147 } 148 149 /* Return the function containing pc value PC. 150 Returns 0 if function is not known. 151 Backward compatibility, no section */ 152 153 struct symbol * 154 find_pc_function (CORE_ADDR pc) 155 { 156 return find_pc_sect_function (pc, find_pc_mapped_section (pc)); 157 } 158 159 /* These variables are used to cache the most recent result 160 of find_pc_partial_function. */ 161 162 static CORE_ADDR cache_pc_function_low = 0; 163 static CORE_ADDR cache_pc_function_high = 0; 164 static char *cache_pc_function_name = 0; 165 static struct obj_section *cache_pc_function_section = NULL; 166 static int cache_pc_function_is_gnu_ifunc = 0; 167 168 /* Clear cache, e.g. when symbol table is discarded. */ 169 170 void 171 clear_pc_function_cache (void) 172 { 173 cache_pc_function_low = 0; 174 cache_pc_function_high = 0; 175 cache_pc_function_name = (char *) 0; 176 cache_pc_function_section = NULL; 177 cache_pc_function_is_gnu_ifunc = 0; 178 } 179 180 /* Finds the "function" (text symbol) that is smaller than PC but 181 greatest of all of the potential text symbols in SECTION. Sets 182 *NAME and/or *ADDRESS conditionally if that pointer is non-null. 183 If ENDADDR is non-null, then set *ENDADDR to be the end of the 184 function (exclusive), but passing ENDADDR as non-null means that 185 the function might cause symbols to be read. If IS_GNU_IFUNC_P is provided 186 *IS_GNU_IFUNC_P is set to 1 on return if the function is STT_GNU_IFUNC. 187 This function either succeeds or fails (not halfway succeeds). If it 188 succeeds, it sets *NAME, *ADDRESS, and *ENDADDR to real information and 189 returns 1. If it fails, it sets *NAME, *ADDRESS, *ENDADDR and 190 *IS_GNU_IFUNC_P to zero and returns 0. */ 191 192 /* Backward compatibility, no section argument. */ 193 194 int 195 find_pc_partial_function_gnu_ifunc (CORE_ADDR pc, char **name, 196 CORE_ADDR *address, CORE_ADDR *endaddr, 197 int *is_gnu_ifunc_p) 198 { 199 struct obj_section *section; 200 struct symbol *f; 201 struct minimal_symbol *msymbol; 202 struct symtab *symtab = NULL; 203 struct objfile *objfile; 204 int i; 205 CORE_ADDR mapped_pc; 206 207 /* To ensure that the symbol returned belongs to the correct setion 208 (and that the last [random] symbol from the previous section 209 isn't returned) try to find the section containing PC. First try 210 the overlay code (which by default returns NULL); and second try 211 the normal section code (which almost always succeeds). */ 212 section = find_pc_overlay (pc); 213 if (section == NULL) 214 section = find_pc_section (pc); 215 216 mapped_pc = overlay_mapped_address (pc, section); 217 218 if (mapped_pc >= cache_pc_function_low 219 && mapped_pc < cache_pc_function_high 220 && section == cache_pc_function_section) 221 goto return_cached_value; 222 223 msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section); 224 ALL_OBJFILES (objfile) 225 { 226 if (objfile->sf) 227 symtab = objfile->sf->qf->find_pc_sect_symtab (objfile, msymbol, 228 mapped_pc, section, 0); 229 if (symtab) 230 break; 231 } 232 233 if (symtab) 234 { 235 /* Checking whether the msymbol has a larger value is for the 236 "pathological" case mentioned in print_frame_info. */ 237 f = find_pc_sect_function (mapped_pc, section); 238 if (f != NULL 239 && (msymbol == NULL 240 || (BLOCK_START (SYMBOL_BLOCK_VALUE (f)) 241 >= SYMBOL_VALUE_ADDRESS (msymbol)))) 242 { 243 cache_pc_function_low = BLOCK_START (SYMBOL_BLOCK_VALUE (f)); 244 cache_pc_function_high = BLOCK_END (SYMBOL_BLOCK_VALUE (f)); 245 cache_pc_function_name = SYMBOL_LINKAGE_NAME (f); 246 cache_pc_function_section = section; 247 cache_pc_function_is_gnu_ifunc = TYPE_GNU_IFUNC (SYMBOL_TYPE (f)); 248 goto return_cached_value; 249 } 250 } 251 252 /* Not in the normal symbol tables, see if the pc is in a known 253 section. If it's not, then give up. This ensures that anything 254 beyond the end of the text seg doesn't appear to be part of the 255 last function in the text segment. */ 256 257 if (!section) 258 msymbol = NULL; 259 260 /* Must be in the minimal symbol table. */ 261 if (msymbol == NULL) 262 { 263 /* No available symbol. */ 264 if (name != NULL) 265 *name = 0; 266 if (address != NULL) 267 *address = 0; 268 if (endaddr != NULL) 269 *endaddr = 0; 270 if (is_gnu_ifunc_p != NULL) 271 *is_gnu_ifunc_p = 0; 272 return 0; 273 } 274 275 cache_pc_function_low = SYMBOL_VALUE_ADDRESS (msymbol); 276 cache_pc_function_name = SYMBOL_LINKAGE_NAME (msymbol); 277 cache_pc_function_section = section; 278 cache_pc_function_is_gnu_ifunc = MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc; 279 280 /* If the minimal symbol has a size, use it for the cache. 281 Otherwise use the lesser of the next minimal symbol in the same 282 section, or the end of the section, as the end of the 283 function. */ 284 285 if (MSYMBOL_SIZE (msymbol) != 0) 286 cache_pc_function_high = cache_pc_function_low + MSYMBOL_SIZE (msymbol); 287 else 288 { 289 /* Step over other symbols at this same address, and symbols in 290 other sections, to find the next symbol in this section with 291 a different address. */ 292 293 for (i = 1; SYMBOL_LINKAGE_NAME (msymbol + i) != NULL; i++) 294 { 295 if (SYMBOL_VALUE_ADDRESS (msymbol + i) 296 != SYMBOL_VALUE_ADDRESS (msymbol) 297 && SYMBOL_OBJ_SECTION (msymbol + i) 298 == SYMBOL_OBJ_SECTION (msymbol)) 299 break; 300 } 301 302 if (SYMBOL_LINKAGE_NAME (msymbol + i) != NULL 303 && SYMBOL_VALUE_ADDRESS (msymbol + i) 304 < obj_section_endaddr (section)) 305 cache_pc_function_high = SYMBOL_VALUE_ADDRESS (msymbol + i); 306 else 307 /* We got the start address from the last msymbol in the objfile. 308 So the end address is the end of the section. */ 309 cache_pc_function_high = obj_section_endaddr (section); 310 } 311 312 return_cached_value: 313 314 if (address) 315 { 316 if (pc_in_unmapped_range (pc, section)) 317 *address = overlay_unmapped_address (cache_pc_function_low, section); 318 else 319 *address = cache_pc_function_low; 320 } 321 322 if (name) 323 *name = cache_pc_function_name; 324 325 if (endaddr) 326 { 327 if (pc_in_unmapped_range (pc, section)) 328 { 329 /* Because the high address is actually beyond the end of 330 the function (and therefore possibly beyond the end of 331 the overlay), we must actually convert (high - 1) and 332 then add one to that. */ 333 334 *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1, 335 section); 336 } 337 else 338 *endaddr = cache_pc_function_high; 339 } 340 341 if (is_gnu_ifunc_p) 342 *is_gnu_ifunc_p = cache_pc_function_is_gnu_ifunc; 343 344 return 1; 345 } 346 347 /* See find_pc_partial_function_gnu_ifunc, only the IS_GNU_IFUNC_P parameter 348 is omitted here for backward API compatibility. */ 349 350 int 351 find_pc_partial_function (CORE_ADDR pc, char **name, CORE_ADDR *address, 352 CORE_ADDR *endaddr) 353 { 354 return find_pc_partial_function_gnu_ifunc (pc, name, address, endaddr, NULL); 355 } 356 357 /* Return the innermost stack frame executing inside of BLOCK, or NULL 358 if there is no such frame. If BLOCK is NULL, just return NULL. */ 359 360 struct frame_info * 361 block_innermost_frame (struct block *block) 362 { 363 struct frame_info *frame; 364 CORE_ADDR start; 365 CORE_ADDR end; 366 367 if (block == NULL) 368 return NULL; 369 370 start = BLOCK_START (block); 371 end = BLOCK_END (block); 372 373 frame = get_current_frame (); 374 while (frame != NULL) 375 { 376 struct block *frame_block = get_frame_block (frame, NULL); 377 if (frame_block != NULL && contained_in (frame_block, block)) 378 return frame; 379 380 frame = get_prev_frame (frame); 381 } 382 383 return NULL; 384 } 385