libjava/stacktrace.cc

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