rev 9211 : 8140645: Recent Developments for AIX Summary: Port recent developments from SAP for AIX to the OpenJDK
1 /* 2 * Copyright 2012, 2013 SAP AG. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "asm/assembler.hpp" 26 #include "memory/allocation.hpp" 27 #include "memory/allocation.inline.hpp" 28 #include "runtime/os.hpp" 29 #include "loadlib_aix.hpp" 30 #include "porting_aix.hpp" 31 #include "utilities/debug.hpp" 32 33 #include <demangle.h> 34 #include <sys/debug.h> 35 36 ////////////////////////////////// 37 // Provide implementation for dladdr based on LoadedLibraries pool and 38 // traceback table scan (see getFuncName). 39 40 // Search traceback table in stack, 41 // return procedure name from trace back table. 42 #define MAX_FUNC_SEARCH_LEN 0x10000 43 // Any PC below this value is considered toast. 44 #define MINIMUM_VALUE_FOR_PC ((unsigned int*)0x1024) 45 46 #define PTRDIFF_BYTES(p1,p2) (((ptrdiff_t)p1) - ((ptrdiff_t)p2)) 47 48 // Align a pointer without having to cast. 49 inline char* align_ptr_up(char* ptr, intptr_t alignment) { 50 return (char*) align_size_up((intptr_t)ptr, alignment); 51 } 52 53 // Trace if verbose to tty. 54 // I use these now instead of the Xtrace system because the latter is 55 // not available at init time, hence worthless. Until we fix this, all 56 // tracing here is done with -XX:+Verbose. 57 #define trcVerbose(fmt, ...) { \ 58 if (Verbose) { \ 59 fprintf(stderr, fmt, ##__VA_ARGS__); \ 60 fputc('\n', stderr); fflush(stderr); \ 61 } \ 62 } 63 #define ERRBYE(s) { trcVerbose(s); return -1; } 64 65 // Unfortunately, the interface of dladdr makes the implementator 66 // responsible for maintaining memory for function name/library 67 // name. I guess this is because most OS's keep those values as part 68 // of the mapped executable image ready to use. On AIX, this doesn't 69 // work, so I have to keep the returned strings. For now, I do this in 70 // a primitive string map. Should this turn out to be a performance 71 // problem, a better hashmap has to be used. 72 class fixed_strings { 73 struct node : public CHeapObj<mtInternal> { 74 char* v; 75 node* next; 76 }; 77 78 node* first; 79 80 public: 81 82 fixed_strings() : first(0) {} 83 ~fixed_strings() { 84 node* n = first; 85 while (n) { 86 node* p = n; 87 n = n->next; 88 os::free(p->v); 89 delete p; 90 } 91 } 92 93 char* intern(const char* s) { 94 for (node* n = first; n; n = n->next) { 95 if (strcmp(n->v, s) == 0) { 96 return n->v; 97 } 98 } 99 node* p = new node; 100 p->v = os::strdup_check_oom(s); 101 p->next = first; 102 first = p; 103 return p->v; 104 } 105 }; 106 107 static fixed_strings dladdr_fixed_strings; 108 109 // Given a code pointer, returns the function name and the displacement. 110 // Function looks for the traceback table at the end of the function. 111 extern "C" int getFuncName( 112 codeptr_t pc, // [in] program counter 113 char* p_name, size_t namelen, // [out] optional: function name ("" if not available) 114 int* p_displacement, // [out] optional: displacement (-1 if not available) 115 const struct tbtable** p_tb, // [out] optional: ptr to traceback table to get further 116 // information (NULL if not available) 117 char* p_errmsg, size_t errmsglen,// [out] optional: user provided buffer for error messages 118 bool demangle // [in] whether to demangle the name 119 ) { 120 struct tbtable* tb = 0; 121 unsigned int searchcount = 0; 122 123 // initialize output parameters 124 if (p_name && namelen > 0) { 125 *p_name = '\0'; 126 } 127 if (p_errmsg && errmsglen > 0) { 128 *p_errmsg = '\0'; 129 } 130 if (p_displacement) { 131 *p_displacement = -1; 132 } 133 if (p_tb) { 134 *p_tb = NULL; 135 } 136 137 // weed out obvious bogus states 138 if (pc < MINIMUM_VALUE_FOR_PC) { 139 ERRBYE("invalid program counter"); 140 } 141 142 codeptr_t pc2 = pc; 143 144 // make sure the pointer is word aligned. 145 pc2 = (codeptr_t) align_ptr_up((char*)pc2, 4); 146 147 // Find start of traceback table. 148 // (starts after code, is marked by word-aligned (32bit) zeros) 149 while ((*pc2 != NULL) && (searchcount++ < MAX_FUNC_SEARCH_LEN)) { 150 pc2++; 151 } 152 if (*pc2 != 0) { 153 ERRBYE("could not find traceback table within 5000 bytes of program counter"); 154 } 155 // 156 // Set up addressability to the traceback table 157 // 158 tb = (struct tbtable*) (pc2 + 1); 159 160 // Is this really a traceback table? No way to be sure but 161 // some indicators we can check. 162 if (tb->tb.lang >= 0xf && tb->tb.lang <= 0xfb) { 163 // Language specifiers, go from 0 (C) to 14 (Objective C). 164 // According to spec, 0xf-0xfa reserved, 0xfb-0xff reserved for ibm. 165 ERRBYE("not a traceback table"); 166 } 167 168 // Existence of fields in the tbtable extension are contingent upon 169 // specific fields in the base table. Check for their existence so 170 // that we can address the function name if it exists. 171 pc2 = (codeptr_t) tb + 172 sizeof(struct tbtable_short)/sizeof(int); 173 if (tb->tb.fixedparms != 0 || tb->tb.floatparms != 0) 174 pc2++; 175 176 if (tb->tb.has_tboff == TRUE) { 177 178 // I want to know the displacement 179 const unsigned int tb_offset = *pc2; 180 codeptr_t start_of_procedure = 181 (codeptr_t)(((char*)tb) - 4 - tb_offset); // (-4 to omit leading 0000) 182 183 // Weed out the cases where we did find the wrong traceback table. 184 if (pc < start_of_procedure) { 185 ERRBYE("could not find (the real) traceback table within 5000 bytes of program counter"); 186 } 187 188 // return the displacement 189 if (p_displacement) { 190 (*p_displacement) = (int) PTRDIFF_BYTES(pc, start_of_procedure); 191 } 192 193 pc2++; 194 } else { 195 // return -1 for displacement 196 if (p_displacement) { 197 (*p_displacement) = -1; 198 } 199 } 200 201 if (tb->tb.int_hndl == TRUE) 202 pc2++; 203 204 if (tb->tb.has_ctl == TRUE) 205 pc2 += (*pc2) + 1; // don't care 206 207 // 208 // return function name if it exists. 209 // 210 if (p_name && namelen > 0) { 211 if (tb->tb.name_present) { 212 char buf[256]; 213 const short l = MIN2<short>(*((short*)pc2), sizeof(buf) - 1); 214 memcpy(buf, (char*)pc2 + sizeof(short), l); 215 buf[l] = '\0'; 216 217 p_name[0] = '\0'; 218 219 // If it is a C++ name, try and demangle it using the Demangle interface (see demangle.h). 220 if (demangle) { 221 char* rest; 222 Name* const name = Demangle(buf, rest); 223 if (name) { 224 const char* const demangled_name = name->Text(); 225 if (demangled_name) { 226 strncpy(p_name, demangled_name, namelen-1); 227 p_name[namelen-1] = '\0'; 228 } 229 delete name; 230 } 231 } 232 233 // Fallback: if demangling did not work, just provide the unmangled name. 234 if (p_name[0] == '\0') { 235 strncpy(p_name, buf, namelen-1); 236 p_name[namelen-1] = '\0'; 237 } 238 239 } else { 240 strncpy(p_name, "<nameless function>", namelen-1); 241 p_name[namelen-1] = '\0'; 242 } 243 } 244 // Return traceback table, if user wants it. 245 if (p_tb) { 246 (*p_tb) = tb; 247 } 248 249 return 0; 250 } 251 252 // Special implementation of dladdr for Aix based on LoadedLibraries 253 // Note: dladdr returns non-zero for ok, 0 for error! 254 // Note: dladdr is not posix, but a non-standard GNU extension. So this tries to 255 // fulfill the contract of dladdr on Linux (see http://linux.die.net/man/3/dladdr) 256 // Note: addr may be both an AIX function descriptor or a real code pointer 257 // to the entry of a function. 258 extern "C" 259 int dladdr(void* addr, Dl_info* info) { 260 261 if (!addr) { 262 return 0; 263 } 264 265 assert(info, ""); 266 267 int rc = 0; 268 269 const char* const ZEROSTRING = ""; 270 271 // Always return a string, even if a "" one. Linux dladdr manpage 272 // does not say anything about returning NULL 273 info->dli_fname = ZEROSTRING; 274 info->dli_sname = ZEROSTRING; 275 info->dli_saddr = NULL; 276 277 address p = (address) addr; 278 const LoadedLibraryModule* lib = NULL; 279 280 enum { noclue, code, data } type = noclue; 281 282 trcVerbose("dladdr(%p)...", p); 283 284 // Note: input address may be a function. I accept both a pointer to 285 // the entry of a function and a pointer to the function decriptor. 286 // (see ppc64 ABI) 287 lib = LoadedLibraries::find_for_text_address(p); 288 if (lib) { 289 type = code; 290 } 291 292 if (!lib) { 293 // Not a pointer into any text segment. Is it a function descriptor? 294 const FunctionDescriptor* const pfd = (const FunctionDescriptor*) p; 295 p = pfd->entry(); 296 if (p) { 297 lib = LoadedLibraries::find_for_text_address(p); 298 if (lib) { 299 type = code; 300 } 301 } 302 } 303 304 if (!lib) { 305 // Neither direct code pointer nor function descriptor. A data ptr? 306 p = (address)addr; 307 lib = LoadedLibraries::find_for_data_address(p); 308 if (lib) { 309 type = data; 310 } 311 } 312 313 // If we did find the shared library this address belongs to (either 314 // code or data segment) resolve library path and, if possible, the 315 // symbol name. 316 if (lib) { 317 const char* const interned_libpath = 318 dladdr_fixed_strings.intern(lib->get_fullpath()); 319 if (interned_libpath) { 320 info->dli_fname = interned_libpath; 321 } 322 323 if (type == code) { 324 325 // For code symbols resolve function name and displacement. Use 326 // displacement to calc start of function. 327 char funcname[256] = ""; 328 int displacement = 0; 329 330 if (getFuncName((codeptr_t) p, funcname, sizeof(funcname), &displacement, 331 NULL, NULL, 0, true /* demangle */) == 0) { 332 if (funcname[0] != '\0') { 333 const char* const interned = dladdr_fixed_strings.intern(funcname); 334 info->dli_sname = interned; 335 trcVerbose("... function name: %s ...", interned); 336 } 337 338 // From the displacement calculate the start of the function. 339 if (displacement != -1) { 340 info->dli_saddr = p - displacement; 341 } else { 342 info->dli_saddr = p; 343 } 344 } else { 345 346 // No traceback table found. Just assume the pointer is it. 347 info->dli_saddr = p; 348 349 } 350 351 } else if (type == data) { 352 353 // For data symbols. 354 info->dli_saddr = p; 355 356 } else { 357 ShouldNotReachHere(); 358 } 359 360 rc = 1; // success: return 1 [sic] 361 362 } 363 364 // sanity checks. 365 if (rc) { 366 assert(info->dli_fname, ""); 367 assert(info->dli_sname, ""); 368 assert(info->dli_saddr, ""); 369 } 370 371 return rc; // error: return 0 [sic] 372 373 } --- EOF ---