porting_aix.cpp revision 6856:5217fa82f1a4
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. 49inline 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. 72class 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 107static 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. 111extern "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 ) { 119 struct tbtable* tb = 0; 120 unsigned int searchcount = 0; 121 122 // initialize output parameters 123 if (p_name && namelen > 0) { 124 *p_name = '\0'; 125 } 126 if (p_errmsg && errmsglen > 0) { 127 *p_errmsg = '\0'; 128 } 129 if (p_displacement) { 130 *p_displacement = -1; 131 } 132 if (p_tb) { 133 *p_tb = NULL; 134 } 135 136 // weed out obvious bogus states 137 if (pc < MINIMUM_VALUE_FOR_PC) { 138 ERRBYE("invalid program counter"); 139 } 140 141 codeptr_t pc2 = pc; 142 143 // make sure the pointer is word aligned. 144 pc2 = (codeptr_t) align_ptr_up((char*)pc2, 4); 145 146 // Find start of traceback table. 147 // (starts after code, is marked by word-aligned (32bit) zeros) 148 while ((*pc2 != NULL) && (searchcount++ < MAX_FUNC_SEARCH_LEN)) { 149 pc2++; 150 } 151 if (*pc2 != 0) { 152 ERRBYE("could not find traceback table within 5000 bytes of program counter"); 153 } 154 // 155 // Set up addressability to the traceback table 156 // 157 tb = (struct tbtable*) (pc2 + 1); 158 159 // Is this really a traceback table? No way to be sure but 160 // some indicators we can check. 161 if (tb->tb.lang >= 0xf && tb->tb.lang <= 0xfb) { 162 // Language specifiers, go from 0 (C) to 14 (Objective C). 163 // According to spec, 0xf-0xfa reserved, 0xfb-0xff reserved for ibm. 164 ERRBYE("not a traceback table"); 165 } 166 167 // Existence of fields in the tbtable extension are contingent upon 168 // specific fields in the base table. Check for their existence so 169 // that we can address the function name if it exists. 170 pc2 = (codeptr_t) tb + 171 sizeof(struct tbtable_short)/sizeof(int); 172 if (tb->tb.fixedparms != 0 || tb->tb.floatparms != 0) 173 pc2++; 174 175 if (tb->tb.has_tboff == TRUE) { 176 177 // I want to know the displacement 178 const unsigned int tb_offset = *pc2; 179 codeptr_t start_of_procedure = 180 (codeptr_t)(((char*)tb) - 4 - tb_offset); // (-4 to omit leading 0000) 181 182 // Weed out the cases where we did find the wrong traceback table. 183 if (pc < start_of_procedure) { 184 ERRBYE("could not find (the real) traceback table within 5000 bytes of program counter"); 185 } 186 187 // return the displacement 188 if (p_displacement) { 189 (*p_displacement) = (int) PTRDIFF_BYTES(pc, start_of_procedure); 190 } 191 192 pc2++; 193 } else { 194 // return -1 for displacement 195 if (p_displacement) { 196 (*p_displacement) = -1; 197 } 198 } 199 200 if (tb->tb.int_hndl == TRUE) 201 pc2++; 202 203 if (tb->tb.has_ctl == TRUE) 204 pc2 += (*pc2) + 1; // don't care 205 206 // 207 // return function name if it exists. 208 // 209 if (p_name && namelen > 0) { 210 if (tb->tb.name_present) { 211 char buf[256]; 212 const short l = MIN2<short>(*((short*)pc2), sizeof(buf) - 1); 213 memcpy(buf, (char*)pc2 + sizeof(short), l); 214 buf[l] = '\0'; 215 216 p_name[0] = '\0'; 217 218 // If it is a C++ name, try and demangle it using the Demangle interface (see demangle.h). 219 char* rest; 220 Name* const name = Demangle(buf, rest); 221 if (name) { 222 const char* const demangled_name = name->Text(); 223 if (demangled_name) { 224 strncpy(p_name, demangled_name, namelen-1); 225 p_name[namelen-1] = '\0'; 226 } 227 delete name; 228 } 229 230 // Fallback: if demangling did not work, just provide the unmangled name. 231 if (p_name[0] == '\0') { 232 strncpy(p_name, buf, namelen-1); 233 p_name[namelen-1] = '\0'; 234 } 235 236 } else { 237 strncpy(p_name, "<nameless function>", namelen-1); 238 p_name[namelen-1] = '\0'; 239 } 240 } 241 // Return traceback table, if user wants it. 242 if (p_tb) { 243 (*p_tb) = tb; 244 } 245 246 return 0; 247} 248 249// Special implementation of dladdr for Aix based on LoadedLibraries 250// Note: dladdr returns non-zero for ok, 0 for error! 251// Note: dladdr is not posix, but a non-standard GNU extension. So this tries to 252// fulfill the contract of dladdr on Linux (see http://linux.die.net/man/3/dladdr) 253// Note: addr may be both an AIX function descriptor or a real code pointer 254// to the entry of a function. 255extern "C" 256int dladdr(void* addr, Dl_info* info) { 257 258 if (!addr) { 259 return 0; 260 } 261 262 assert(info, ""); 263 264 int rc = 0; 265 266 const char* const ZEROSTRING = ""; 267 268 // Always return a string, even if a "" one. Linux dladdr manpage 269 // does not say anything about returning NULL 270 info->dli_fname = ZEROSTRING; 271 info->dli_sname = ZEROSTRING; 272 info->dli_saddr = NULL; 273 274 address p = (address) addr; 275 const LoadedLibraryModule* lib = NULL; 276 277 enum { noclue, code, data } type = noclue; 278 279 trcVerbose("dladdr(%p)...", p); 280 281 // Note: input address may be a function. I accept both a pointer to 282 // the entry of a function and a pointer to the function decriptor. 283 // (see ppc64 ABI) 284 lib = LoadedLibraries::find_for_text_address(p); 285 if (lib) { 286 type = code; 287 } 288 289 if (!lib) { 290 // Not a pointer into any text segment. Is it a function descriptor? 291 const FunctionDescriptor* const pfd = (const FunctionDescriptor*) p; 292 p = pfd->entry(); 293 if (p) { 294 lib = LoadedLibraries::find_for_text_address(p); 295 if (lib) { 296 type = code; 297 } 298 } 299 } 300 301 if (!lib) { 302 // Neither direct code pointer nor function descriptor. A data ptr? 303 p = (address)addr; 304 lib = LoadedLibraries::find_for_data_address(p); 305 if (lib) { 306 type = data; 307 } 308 } 309 310 // If we did find the shared library this address belongs to (either 311 // code or data segment) resolve library path and, if possible, the 312 // symbol name. 313 if (lib) { 314 const char* const interned_libpath = 315 dladdr_fixed_strings.intern(lib->get_fullpath()); 316 if (interned_libpath) { 317 info->dli_fname = interned_libpath; 318 } 319 320 if (type == code) { 321 322 // For code symbols resolve function name and displacement. Use 323 // displacement to calc start of function. 324 char funcname[256] = ""; 325 int displacement = 0; 326 327 if (getFuncName((codeptr_t) p, funcname, sizeof(funcname), &displacement, 328 NULL, NULL, 0) == 0) { 329 if (funcname[0] != '\0') { 330 const char* const interned = dladdr_fixed_strings.intern(funcname); 331 info->dli_sname = interned; 332 trcVerbose("... function name: %s ...", interned); 333 } 334 335 // From the displacement calculate the start of the function. 336 if (displacement != -1) { 337 info->dli_saddr = p - displacement; 338 } else { 339 info->dli_saddr = p; 340 } 341 } else { 342 343 // No traceback table found. Just assume the pointer is it. 344 info->dli_saddr = p; 345 346 } 347 348 } else if (type == data) { 349 350 // For data symbols. 351 info->dli_saddr = p; 352 353 } else { 354 ShouldNotReachHere(); 355 } 356 357 rc = 1; // success: return 1 [sic] 358 359 } 360 361 // sanity checks. 362 if (rc) { 363 assert(info->dli_fname, ""); 364 assert(info->dli_sname, ""); 365 assert(info->dli_saddr, ""); 366 } 367 368 return rc; // error: return 0 [sic] 369 370} 371