libjava/stacktrace.cc

   1 // stacktrace.cc - Functions for unwinding & inspecting the call stack.
   2
   3 /* Copyright (C) 2005, 2006  Free Software Foundation
   4
   5    This file is part of libgcj.
   6
   7 This software is copyrighted work licensed under the terms of the
   8 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
   9 details.  */
  10
  11 #include <config.h>
  12 #include <platform.h>
  13
  14 #include <jvm.h>
  15 #include <gcj/cni.h>
  16 #include <java-interp.h>
  17 #include <java-stack.h>
  18
  19 #include <stdio.h>
  20
  21 #include <java/lang/Class.h>
  22 #include <java/lang/Long.h>
  23 #include <java/util/ArrayList.h>
  24 #include <java/util/IdentityHashMap.h>
  25 #include <gnu/java/lang/MainThread.h>
  26 #include <gnu/gcj/runtime/NameFinder.h>
  27 #include <gnu/gcj/runtime/StringBuffer.h>
  28
  29 #include <sysdep/backtrace.h>
  30 #include <sysdep/descriptor.h>
  31
  32 using namespace java::lang;
  33 using namespace java::lang::reflect;
  34 using namespace java::util;
  35 using namespace gnu::gcj::runtime;
  36
  37 // Maps ncode values to their containing native class.
  38 // NOTE: Currently this Map contradicts class GC for native classes. This map
  39 // (and the "new class stack") will need to use WeakReferences in order to
  40 // enable native class GC.
  41 static java::util::IdentityHashMap *ncodeMap;
  42
  43 // Check the "class stack" for any classes initialized since we were last
  44 // called, and add them to ncodeMap.
  45 void
  46 _Jv_StackTrace::UpdateNCodeMap ()
  47 {
  48   // The Map should be large enough so that a typical Java app doesn't cause
  49   // it to rehash, without using too much memory. ~5000 entries should be
  50   // enough.
  51   if (ncodeMap == NULL)
  52     ncodeMap = new java::util::IdentityHashMap (5087);
  53
  54   jclass klass;
  55   while ((klass = _Jv_PopClass ()))
  56     if (!_Jv_IsInterpretedClass (klass))
  57       {
  58         //printf ("got %s\n", klass->name->data);
  59         for (int i = 0; i < klass->method_count; i++)
  60           {
  61             _Jv_Method *method = &klass->methods[i];
  62             void *ncode = method->ncode;
  63             // Add non-abstract methods to ncodeMap.
  64             if (ncode)
  65               {
  66                 ncode = UNWRAP_FUNCTION_DESCRIPTOR (ncode);
  67                 ncodeMap->put ((java::lang::Object *) ncode, klass);
  68               }
  69           }
  70       }
  71 }
  72
  73 // Given a native frame, return the class which this code belongs
  74 // to. Returns NULL if this IP is not associated with a native Java class.
  75 // If NCODE is supplied, it will be set with the ip for the entry point of the
  76 // enclosing method.
  77 jclass
  78 _Jv_StackTrace::ClassForFrame (_Jv_StackFrame *frame)
  79 {
  80   JvAssert (frame->type == frame_native);
  81   jclass klass = NULL;
  82
  83   // look it up in ncodeMap
  84   if (frame->start_ip)
  85     klass = (jclass) ncodeMap->get ((jobject) frame->start_ip);
  86
  87   return klass;
  88 }
  89
  90 _Unwind_Reason_Code
  91 _Jv_StackTrace::UnwindTraceFn (struct _Unwind_Context *context, void *state_ptr)
  92 {
  93   _Jv_UnwindState *state = (_Jv_UnwindState *) state_ptr;
  94   jint pos = state->pos;
  95
  96   // Check if the trace buffer needs to be extended.
  97   if (pos == state->length)
  98     {
  99       int newLength = state->length * 2;
 100       void *newFrames = _Jv_AllocBytes (newLength * sizeof(_Jv_StackFrame));
 101       memcpy (newFrames, state->frames, state->length * sizeof(_Jv_StackFrame));
 102       state->frames = (_Jv_StackFrame *) newFrames;
 103       state->length = newLength;
 104     }
 105
 106   void *func_addr = (void *) _Unwind_GetRegionStart (context);
 107
 108   // If we see the interpreter's main function, "pop" an entry off the
 109   // interpreter stack and use that instead, so that the trace goes through
 110   // the java code and not the interpreter itself. This assumes a 1:1
 111   // correspondance between call frames in the interpreted stack and occurances
 112   // of _Jv_InterpMethod::run() on the native stack.
 113 #ifdef INTERPRETER
 114   void *interp_run = (void *) &_Jv_InterpMethod::run;
 115   if (func_addr == UNWRAP_FUNCTION_DESCRIPTOR (interp_run))
 116     {
 117       state->frames[pos].type = frame_interpreter;
 118       state->frames[pos].interp.meth = state->interp_frame->self;
 119       state->frames[pos].interp.pc = state->interp_frame->pc;
 120       state->interp_frame = state->interp_frame->next;
 121     }
 122   else
 123 #endif
 124     {
 125       _Unwind_Ptr ip;
 126       int ip_before_insn = 0;
 127       ip = _Unwind_GetIPInfo (context, &ip_before_insn);
 128
 129       // If the unwinder gave us a 'return' address, roll it back a little
 130       // to ensure we get the correct line number for the call itself.
 131       if (! ip_before_insn)
 132         --ip;
 133
 134       state->frames[pos].type = frame_native;
 135       state->frames[pos].ip = (void *) ip;
 136       state->frames[pos].start_ip = func_addr;
 137     }
 138
 139   _Unwind_Reason_Code result = _URC_NO_REASON;
 140   if (state->trace_function != NULL)
 141     result = (state->trace_function) (state);
 142   state->pos++;
 143   return result;
 144 }
 145
 146 // Return a raw stack trace from the current point of execution. The raw
 147 // trace will include all functions that have unwind info.
 148 _Jv_StackTrace *
 149 _Jv_StackTrace::GetStackTrace(void)
 150 {
 151   int trace_size = 100;
 152   _Jv_StackFrame frames[trace_size];
 153   _Jv_UnwindState state (trace_size);
 154   state.frames = (_Jv_StackFrame *) &frames;
 155
 156   _Unwind_Backtrace (UnwindTraceFn, &state);
 157
 158   // Copy the trace and return it.
 159   int traceSize = sizeof (_Jv_StackTrace) +
 160     (sizeof (_Jv_StackFrame) * state.pos);
 161   _Jv_StackTrace *trace = (_Jv_StackTrace *) _Jv_AllocBytes (traceSize);
 162   trace->length = state.pos;
 163   memcpy (trace->frames, state.frames, sizeof (_Jv_StackFrame) * state.pos);
 164   return trace;
 165 }
 166
 167 void
 168 _Jv_StackTrace::getLineNumberForFrame(_Jv_StackFrame *frame, NameFinder *finder,
 169                                       jstring *sourceFileName, jint *lineNum,
 170                                       jstring *methodName)
 171 {
 172 #ifdef INTERPRETER
 173   if (frame->type == frame_interpreter)
 174     {
 175       _Jv_InterpMethod *interp_meth = frame->interp.meth;
 176       _Jv_InterpClass *interp_class =
 177          (_Jv_InterpClass *) interp_meth->defining_class->aux_info;
 178       *sourceFileName = interp_class->source_file_name;
 179       // The interpreter advances the PC before executing an instruction,
 180       // so roll-back 1 byte to ensure the line number is accurate.
 181       *lineNum = interp_meth->get_source_line(frame->interp.pc - 1);
 182       return;
 183     }
 184 #endif
 185
 186   // Use _Jv_platform_dladdr() to determine in which binary the address IP
 187   // resides.
 188   _Jv_AddrInfo info;
 189   jstring binaryName = NULL;
 190   const char *argv0 = _Jv_GetSafeArg(0);
 191
 192   void *ip = frame->ip;
 193   _Unwind_Ptr offset = 0;
 194
 195   if (_Jv_platform_dladdr (ip, &info))
 196     {
 197       if (info.file_name)
 198         binaryName = JvNewStringUTF (info.file_name);
 199       else
 200         return;
 201
 202       if (*methodName == NULL && info.sym_name)
 203         *methodName = JvNewStringUTF (info.sym_name);
 204
 205       // addr2line expects relative addresses for shared libraries.
 206       if (strcmp (info.file_name, argv0) == 0)
 207         offset = (_Unwind_Ptr) ip;
 208       else
 209         offset = (_Unwind_Ptr) ip - (_Unwind_Ptr) info.base;
 210
 211       finder->lookup (binaryName, (jlong) offset);
 212       *sourceFileName = finder->getSourceFile();
 213       *lineNum = finder->getLineNum();
 214       if (*lineNum == -1 && NameFinder::showRaw())
 215         {
 216           gnu::gcj::runtime::StringBuffer *t =
 217             new gnu::gcj::runtime::StringBuffer(binaryName);
 218           t->append ((jchar)' ');
 219           t->append ((jchar)'[');
 220           // + 1 to compensate for the - 1 adjustment above;
 221           t->append (Long::toHexString (offset + 1));
 222           t->append ((jchar)']');
 223           *sourceFileName = t->toString();
 224         }
 225     }
 226 }
 227
 228 // Look up class and method info for the given stack frame, setting
 229 // frame->klass and frame->meth if they are known.
 230 void
 231 _Jv_StackTrace::FillInFrameInfo (_Jv_StackFrame *frame)
 232 {
 233   jclass klass = NULL;
 234   _Jv_Method *meth = NULL;
 235
 236   if (frame->type == frame_native)
 237     {
 238       klass = _Jv_StackTrace::ClassForFrame (frame);
 239
 240       if (klass != NULL)
 241         // Find method in class
 242         for (int j = 0; j < klass->method_count; j++)
 243           {
 244             void *wncode = UNWRAP_FUNCTION_DESCRIPTOR (klass->methods[j].ncode);
 245             if (wncode == frame->start_ip)
 246               {
 247                 meth = &klass->methods[j];
 248                 break;
 249               }
 250           }
 251     }
 252 #ifdef INTERPRETER
 253   else if (frame->type == frame_interpreter)
 254     {
 255       _Jv_InterpMethod *interp_meth = frame->interp.meth;
 256       klass = interp_meth->defining_class;
 257       meth = interp_meth->self;
 258     }
 259 #endif
 260   else
 261     JvFail ("Unknown frame type");
 262
 263   frame->klass = klass;
 264   frame->meth = meth;
 265 }
 266
 267 // Convert raw stack frames to a Java array of StackTraceElement objects.
 268 JArray< ::java::lang::StackTraceElement *>*
 269 _Jv_StackTrace::GetStackTraceElements (_Jv_StackTrace *trace,
 270   Throwable *throwable __attribute__((unused)))
 271 {
 272   ArrayList *list = new ArrayList ();
 273
 274 #if defined (SJLJ_EXCEPTIONS) && ! defined (WIN32)
 275   // We can't use the nCodeMap without unwinder support. Instead,
 276   // fake the method name by giving the IP in hex - better than nothing.
 277   jstring hex = JvNewStringUTF ("0x");
 278
 279   for (int i = 0; i < trace->length; i++)
 280     {
 281       jstring sourceFileName = NULL;
 282       jint lineNum = -1;
 283       _Jv_StackFrame *frame = &trace->frames[i];
 284
 285       jstring className = NULL;
 286       jstring methodName = hex->concat (Long::toHexString ((jlong) frame->ip));
 287
 288       StackTraceElement *element = new StackTraceElement (sourceFileName,
 289         lineNum, className, methodName, 0);
 290       list->add (element);
 291     }
 292
 293 #else /* SJLJ_EXCEPTIONS && !WIN32 */
 294
 295   //JvSynchronized (ncodeMap);
 296   UpdateNCodeMap ();
 297
 298   NameFinder *finder = new NameFinder();
 299   int start_idx = 0;
 300   int end_idx = trace->length - 1;
 301
 302   // First pass: strip superfluous frames from beginning and end of the trace.
 303   for (int i = 0; i < trace->length; i++)
 304     {
 305       _Jv_StackFrame *frame = &trace->frames[i];
 306       FillInFrameInfo (frame);
 307
 308       if (!frame->klass || !frame->meth)
 309         // Not a Java frame.
 310         continue;
 311
 312       // Throw away the top of the stack till we see:
 313       //  - the constructor(s) of this Throwable, or
 314       //  - the Throwable.fillInStackTrace call.
 315       if (frame->klass == throwable->getClass()
 316           && strcmp (frame->meth->name->chars(), "<init>") == 0)
 317         start_idx = i + 1;
 318
 319       if (frame->klass == &Throwable::class$
 320           && strcmp (frame->meth->name->chars(), "fillInStackTrace") == 0)
 321         start_idx = i + 1;
 322
 323       // End the trace at the application's main() method if we see call_main.
 324       if (frame->klass == &gnu::java::lang::MainThread::class$
 325           && strcmp (frame->meth->name->chars(), "call_main") == 0)
 326         end_idx = i - 1;
 327     }
 328
 329   const jboolean remove_unknown
 330     = gnu::gcj::runtime::NameFinder::removeUnknown();
 331
 332   // Second pass: Look up line-number info for remaining frames.
 333   for (int i = start_idx; i <= end_idx; i++)
 334     {
 335       _Jv_StackFrame *frame = &trace->frames[i];
 336
 337       if (frame->klass == NULL && remove_unknown)
 338         // Not a Java frame.
 339         continue;
 340
 341       jstring className = NULL;
 342       if (frame->klass != NULL)
 343         className = frame->klass->getName ();
 344
 345       jstring methodName = NULL;
 346       if (frame->meth)
 347         methodName = JvNewStringUTF (frame->meth->name->chars());
 348
 349       jstring sourceFileName = NULL;
 350       jint lineNum = -1;
 351
 352       getLineNumberForFrame(frame, finder, &sourceFileName, &lineNum,
 353                             &methodName);
 354
 355       StackTraceElement *element = new StackTraceElement (sourceFileName, lineNum,
 356         className, methodName, 0);
 357       list->add (element);
 358     }
 359
 360   finder->close();
 361 #endif /* SJLJ_EXCEPTIONS && !WIN32 */
 362
 363   JArray<Object *> *array = JvNewObjectArray (list->size (),
 364     &StackTraceElement::class$, NULL);
 365
 366   return (JArray<StackTraceElement *>*) list->toArray (array);
 367 }
 368
 369 struct CallingClassTraceData
 370 {
 371   jclass checkClass;
 372   jclass foundClass;
 373   _Jv_Method *foundMeth;
 374   bool seen_checkClass;
 375 };
 376
 377 _Unwind_Reason_Code
 378 _Jv_StackTrace::calling_class_trace_fn (_Jv_UnwindState *state)
 379 {
 380   CallingClassTraceData *trace_data = (CallingClassTraceData *)
 381     state->trace_data;
 382   _Jv_StackFrame *frame = &state->frames[state->pos];
 383   FillInFrameInfo (frame);
 384
 385   if (trace_data->seen_checkClass
 386       && frame->klass
 387       && frame->klass != trace_data->checkClass)
 388     {
 389       trace_data->foundClass = frame->klass;
 390       trace_data->foundMeth = frame->meth;
 391       return _URC_NORMAL_STOP;
 392     }
 393
 394   if (frame->klass == trace_data->checkClass)
 395     trace_data->seen_checkClass = true;
 396
 397   return _URC_NO_REASON;
 398 }
 399
 400 // Find the class immediately above the given class on the call stack. Any
 401 // intermediate non-Java
 402 // frames are ignored. If the calling class could not be determined (eg because
 403 // the unwinder is not supported on this platform), NULL is returned.
 404 // This function is used to implement calling-classloader checks and reflection
 405 // accessibility checks.
 406 // CHECKCLASS is typically the class calling GetCallingClass. The first class
 407 // above CHECKCLASS on the call stack will be returned.
 408 jclass
 409 _Jv_StackTrace::GetCallingClass (jclass checkClass)
 410 {
 411   jclass result = NULL;
 412   GetCallerInfo (checkClass, &result, NULL);
 413   return result;
 414 }
 415
 416 void
 417 _Jv_StackTrace::GetCallerInfo (jclass checkClass, jclass *caller_class,
 418   _Jv_Method **caller_meth)
 419 {
 420   int trace_size = 20;
 421   _Jv_StackFrame frames[trace_size];
 422   _Jv_UnwindState state (trace_size);
 423   state.frames = (_Jv_StackFrame *) &frames;
 424
 425   CallingClassTraceData trace_data;
 426   trace_data.checkClass = checkClass;
 427   trace_data.seen_checkClass = false;
 428   trace_data.foundClass = NULL;
 429   trace_data.foundMeth = NULL;
 430
 431   state.trace_function = calling_class_trace_fn;
 432   state.trace_data = (void *) &trace_data;
 433
 434   //JvSynchronized (ncodeMap);
 435   UpdateNCodeMap ();
 436
 437   _Unwind_Backtrace (UnwindTraceFn, &state);
 438
 439   if (caller_class)
 440     *caller_class = trace_data.foundClass;
 441   if (caller_meth)
 442     *caller_meth = trace_data.foundMeth;
 443 }
 444
 445 // Return a java array containing the Java classes on the stack above CHECKCLASS.
 446 JArray<jclass> *
 447 _Jv_StackTrace::GetClassContext (jclass checkClass)
 448 {
 449   JArray<jclass> *result = NULL;
 450
 451   int trace_size = 100;
 452   _Jv_StackFrame frames[trace_size];
 453   _Jv_UnwindState state (trace_size);
 454   state.frames = (_Jv_StackFrame *) &frames;
 455
 456   //JvSynchronized (ncodeMap);
 457   UpdateNCodeMap ();
 458
 459   _Unwind_Backtrace (UnwindTraceFn, &state);
 460
 461   // Count the number of Java frames on the stack.
 462   int jframe_count = 0;
 463   bool seen_checkClass = false;
 464   int start_pos = -1;
 465   for (int i = 0; i < state.pos; i++)
 466     {
 467       _Jv_StackFrame *frame = &state.frames[i];
 468       FillInFrameInfo (frame);
 469
 470       if (seen_checkClass)
 471         {
 472           if (frame->klass)
 473             {
 474               jframe_count++;
 475               if (start_pos == -1)
 476                 start_pos = i;
 477             }
 478         }
 479       else
 480         seen_checkClass = frame->klass == checkClass;
 481     }
 482   result = (JArray<jclass> *) _Jv_NewObjectArray (jframe_count, &Class::class$, NULL);
 483   int pos = 0;
 484
 485   for (int i = start_pos; i < state.pos; i++)
 486     {
 487       _Jv_StackFrame *frame = &state.frames[i];
 488       if (frame->klass)
 489         elements(result)[pos++] = frame->klass;
 490     }
 491   return result;
 492 }
 493
 494 _Unwind_Reason_Code
 495 _Jv_StackTrace::non_system_trace_fn (_Jv_UnwindState *state)
 496 {
 497   _Jv_StackFrame *frame = &state->frames[state->pos];
 498   FillInFrameInfo (frame);
 499
 500   ClassLoader *classLoader = NULL;
 501
 502   if (frame->klass)
 503     {
 504       classLoader = frame->klass->getClassLoaderInternal();
 505 #ifdef INTERPRETER
 506       if (classLoader != NULL)
 507         {
 508           state->trace_data = (void *) classLoader;
 509           return _URC_NORMAL_STOP;
 510         }
 511 #endif
 512     }
 513
 514   return _URC_NO_REASON;
 515 }
 516
 517 ClassLoader *
 518 _Jv_StackTrace::GetFirstNonSystemClassLoader ()
 519 {
 520   int trace_size = 32;
 521   _Jv_StackFrame frames[trace_size];
 522   _Jv_UnwindState state (trace_size);
 523   state.frames = (_Jv_StackFrame *) &frames;
 524   state.trace_function = non_system_trace_fn;
 525   state.trace_data = NULL;
 526
 527   //JvSynchronized (ncodeMap);
 528   UpdateNCodeMap ();
 529
 530   _Unwind_Backtrace (UnwindTraceFn, &state);
 531
 532   if (state.trace_data)
 533     return (ClassLoader *) state.trace_data;
 534
 535   return NULL;
 536 }