1 /*
  2  * Copyright (c) 2003, 2020, Oracle and/or its affiliates. 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 "precompiled.hpp"
 26 #include "code/debugInfoRec.hpp"
 27 #include "code/pcDesc.hpp"
 28 #include "gc/shared/collectedHeap.inline.hpp"
 29 #include "memory/universe.hpp"
 30 #include "oops/oop.inline.hpp"
 31 #include "prims/forte.hpp"
 32 #include "prims/jvmtiExport.hpp"
 33 #include "runtime/frame.inline.hpp"
 34 #include "runtime/javaCalls.hpp"
 35 #include "runtime/thread.inline.hpp"
 36 #include "runtime/vframe.inline.hpp"
 37 #include "runtime/vframeArray.hpp"
 38 
 39 // call frame copied from old .h file and renamed
 40 typedef struct {
 41     jint lineno;                      // line number in the source file
 42     jmethodID method_id;              // method executed in this frame
 43 } ASGCT_CallFrame;
 44 
 45 // call trace copied from old .h file and renamed
 46 typedef struct {
 47     JNIEnv *env_id;                   // Env where trace was recorded
 48     jint num_frames;                  // number of frames in this trace
 49     ASGCT_CallFrame *frames;          // frames
 50 } ASGCT_CallTrace;
 51 
 52 // These name match the names reported by the forte quality kit
 53 enum {
 54   ticks_no_Java_frame         =  0,
 55   ticks_no_class_load         = -1,
 56   ticks_GC_active             = -2,
 57   ticks_unknown_not_Java      = -3,
 58   ticks_not_walkable_not_Java = -4,
 59   ticks_unknown_Java          = -5,
 60   ticks_not_walkable_Java     = -6,
 61   ticks_unknown_state         = -7,
 62   ticks_thread_exit           = -8,
 63   ticks_deopt                 = -9,
 64   ticks_safepoint             = -10
 65 };
 66 
 67 #if INCLUDE_JVMTI
 68 
 69 //-------------------------------------------------------
 70 
 71 // Native interfaces for use by Forte tools.
 72 
 73 
 74 #if !defined(IA64)
 75 
 76 class vframeStreamForte : public vframeStreamCommon {
 77  public:
 78   // constructor that starts with sender of frame fr (top_frame)
 79   vframeStreamForte(JavaThread *jt, frame fr, bool stop_at_java_call_stub);
 80   void forte_next();
 81 };
 82 
 83 
 84 static bool is_decipherable_compiled_frame(JavaThread* thread, frame* fr, CompiledMethod* nm);
 85 static bool is_decipherable_interpreted_frame(JavaThread* thread,
 86                                               frame* fr,
 87                                               Method** method_p,
 88                                               int* bci_p);
 89 
 90 
 91 
 92 
 93 vframeStreamForte::vframeStreamForte(JavaThread *jt,
 94                                      frame fr,
 95                                      bool stop_at_java_call_stub) : vframeStreamCommon(jt, false /* process_frames */) {
 96 
 97   _stop_at_java_call_stub = stop_at_java_call_stub;
 98   _frame = fr;
 99 
100   // We must always have a valid frame to start filling
101 
102   bool filled_in = fill_from_frame();
103 
104   assert(filled_in, "invariant");
105 
106 }
107 
108 
109 // Solaris SPARC Compiler1 needs an additional check on the grandparent
110 // of the top_frame when the parent of the top_frame is interpreted and
111 // the grandparent is compiled. However, in this method we do not know
112 // the relationship of the current _frame relative to the top_frame so
113 // we implement a more broad sanity check. When the previous callee is
114 // interpreted and the current sender is compiled, we verify that the
115 // current sender is also walkable. If it is not walkable, then we mark
116 // the current vframeStream as at the end.
117 void vframeStreamForte::forte_next() {
118   // handle frames with inlining
119   if (_mode == compiled_mode &&
120       vframeStreamCommon::fill_in_compiled_inlined_sender()) {
121     return;
122   }
123 
124   // handle general case
125 
126   int loop_count = 0;
127   int loop_max = MaxJavaStackTraceDepth * 2;
128 
129 
130   do {
131 
132     loop_count++;
133 
134     // By the time we get here we should never see unsafe but better
135     // safe then segv'd
136 
137     if ((loop_max != 0 && loop_count > loop_max) || !_frame.safe_for_sender(_thread)) {
138       _mode = at_end_mode;
139       return;
140     }
141 
142     _frame = _frame.sender(&_reg_map);
143 
144   } while (!fill_from_frame());
145 }
146 
147 // Determine if 'fr' is a decipherable compiled frame. We are already
148 // assured that fr is for a java compiled method.
149 
150 static bool is_decipherable_compiled_frame(JavaThread* thread, frame* fr, CompiledMethod* nm) {
151   assert(nm->is_java_method(), "invariant");
152 
153   if (thread->has_last_Java_frame() && thread->last_Java_pc() == fr->pc()) {
154     // We're stopped at a call into the JVM so look for a PcDesc with
155     // the actual pc reported by the frame.
156     PcDesc* pc_desc = nm->pc_desc_at(fr->pc());
157 
158     // Did we find a useful PcDesc?
159     if (pc_desc != NULL &&
160         pc_desc->scope_decode_offset() != DebugInformationRecorder::serialized_null) {
161       return true;
162     }
163   }
164 
165   // We're at some random pc in the compiled method so search for the PcDesc
166   // whose pc is greater than the current PC.  It's done this way
167   // because the extra PcDescs that are recorded for improved debug
168   // info record the end of the region covered by the ScopeDesc
169   // instead of the beginning.
170   PcDesc* pc_desc = nm->pc_desc_near(fr->pc() + 1);
171 
172   // Now do we have a useful PcDesc?
173   if (pc_desc == NULL ||
174       pc_desc->scope_decode_offset() == DebugInformationRecorder::serialized_null) {
175     // No debug information is available for this PC.
176     //
177     // vframeStreamCommon::fill_from_frame() will decode the frame depending
178     // on the state of the thread.
179     //
180     // Case #1: If the thread is in Java (state == _thread_in_Java), then
181     // the vframeStreamCommon object will be filled as if the frame were a native
182     // compiled frame. Therefore, no debug information is needed.
183     //
184     // Case #2: If the thread is in any other state, then two steps will be performed:
185     // - if asserts are enabled, found_bad_method_frame() will be called and
186     //   the assert in found_bad_method_frame() will be triggered;
187     // - if asserts are disabled, the vframeStreamCommon object will be filled
188     //   as if it were a native compiled frame.
189     //
190     // Case (2) is similar to the way interpreter frames are processed in
191     // vframeStreamCommon::fill_from_interpreter_frame in case no valid BCI
192     // was found for an interpreted frame. If asserts are enabled, the assert
193     // in found_bad_method_frame() will be triggered. If asserts are disabled,
194     // the vframeStreamCommon object will be filled afterwards as if the
195     // interpreter were at the point of entering into the method.
196     return false;
197   }
198 
199   // This PcDesc is useful however we must adjust the frame's pc
200   // so that the vframeStream lookups will use this same pc
201   fr->set_pc(pc_desc->real_pc(nm));
202   return true;
203 }
204 
205 
206 // Determine if 'fr' is a walkable interpreted frame. Returns false
207 // if it is not. *method_p, and *bci_p are not set when false is
208 // returned. *method_p is non-NULL if frame was executing a Java
209 // method. *bci_p is != -1 if a valid BCI in the Java method could
210 // be found.
211 // Note: this method returns true when a valid Java method is found
212 // even if a valid BCI cannot be found.
213 
214 static bool is_decipherable_interpreted_frame(JavaThread* thread,
215                                               frame* fr,
216                                               Method** method_p,
217                                               int* bci_p) {
218   assert(fr->is_interpreted_frame(), "just checking");
219 
220   // top frame is an interpreted frame
221   // check if it is walkable (i.e. valid Method* and valid bci)
222 
223   // Because we may be racing a gc thread the method and/or bci
224   // of a valid interpreter frame may look bad causing us to
225   // fail the is_interpreted_frame_valid test. If the thread
226   // is in any of the following states we are assured that the
227   // frame is in fact valid and we must have hit the race.
228 
229   JavaThreadState state = thread->thread_state();
230   bool known_valid = (state == _thread_in_native ||
231                       state == _thread_in_vm ||
232                       state == _thread_blocked );
233 
234   if (known_valid || fr->is_interpreted_frame_valid(thread)) {
235 
236     // The frame code should completely validate the frame so that
237     // references to Method* and bci are completely safe to access
238     // If they aren't the frame code should be fixed not this
239     // code. However since gc isn't locked out the values could be
240     // stale. This is a race we can never completely win since we can't
241     // lock out gc so do one last check after retrieving their values
242     // from the frame for additional safety
243 
244     Method* method = fr->interpreter_frame_method();
245 
246     // We've at least found a method.
247     // NOTE: there is something to be said for the approach that
248     // if we don't find a valid bci then the method is not likely
249     // a valid method. Then again we may have caught an interpreter
250     // frame in the middle of construction and the bci field is
251     // not yet valid.
252     if (!Method::is_valid_method(method)) return false;
253     *method_p = method; // If the Method* found is invalid, it is
254                         // ignored by forte_fill_call_trace_given_top().
255                         // So set method_p only if the Method is valid.
256 
257     address bcp = fr->interpreter_frame_bcp();
258     int bci = method->validate_bci_from_bcp(bcp);
259 
260     // note: bci is set to -1 if not a valid bci
261     *bci_p = bci;
262     return true;
263   }
264 
265   return false;
266 }
267 
268 
269 // Determine if a Java frame can be found starting with the frame 'fr'.
270 //
271 // Check the return value of find_initial_Java_frame and the value of
272 // 'method_p' to decide on how use the results returned by this method.
273 //
274 // If 'method_p' is not NULL, an initial Java frame has been found and
275 // the stack can be walked starting from that initial frame. In this case,
276 // 'method_p' points to the Method that the initial frame belongs to and
277 // the initial Java frame is returned in initial_frame_p.
278 //
279 // find_initial_Java_frame() returns true if a Method has been found (i.e.,
280 // 'method_p' is not NULL) and the initial frame that belongs to that Method
281 // is decipherable.
282 //
283 // A frame is considered to be decipherable:
284 //
285 // - if the frame is a compiled frame and a PCDesc is available;
286 //
287 // - if the frame is an interpreter frame that is valid or the thread is
288 //   state (_thread_in_native || state == _thread_in_vm || state == _thread_blocked).
289 //
290 // Note that find_initial_Java_frame() can return false even if an initial
291 // Java method was found (e.g., there is no PCDesc available for the method).
292 //
293 // If 'method_p' is NULL, it was not possible to find a Java frame when
294 // walking the stack starting from 'fr'. In this case find_initial_Java_frame
295 // returns false.
296 
297 static bool find_initial_Java_frame(JavaThread* thread,
298                                     frame* fr,
299                                     frame* initial_frame_p,
300                                     Method** method_p,
301                                     int* bci_p) {
302 
303   // It is possible that for a frame containing a compiled method
304   // we can capture the method but no bci. If we get no
305   // bci the frame isn't walkable but the method is usable.
306   // Therefore we init the returned Method* to NULL so the
307   // caller can make the distinction.
308 
309   *method_p = NULL;
310 
311   // On the initial call to this method the frame we get may not be
312   // recognizable to us. This should only happen if we are in a JRT_LEAF
313   // or something called by a JRT_LEAF method.
314 
315   frame candidate = *fr;
316 
317   // If the starting frame we were given has no codeBlob associated with
318   // it see if we can find such a frame because only frames with codeBlobs
319   // are possible Java frames.
320 
321   if (fr->cb() == NULL) {
322 
323     // See if we can find a useful frame
324     int loop_count;
325     int loop_max = MaxJavaStackTraceDepth * 2;
326     RegisterMap map(thread, false, false);
327 
328     for (loop_count = 0; loop_max == 0 || loop_count < loop_max; loop_count++) {
329       if (!candidate.safe_for_sender(thread)) return false;
330       candidate = candidate.sender(&map);
331       if (candidate.cb() != NULL) break;
332     }
333     if (candidate.cb() == NULL) return false;
334   }
335 
336   // We have a frame known to be in the codeCache
337   // We will hopefully be able to figure out something to do with it.
338   int loop_count;
339   int loop_max = MaxJavaStackTraceDepth * 2;
340   RegisterMap map(thread, false, false);
341 
342   for (loop_count = 0; loop_max == 0 || loop_count < loop_max; loop_count++) {
343 
344     if (candidate.is_entry_frame()) {
345       // jcw is NULL if the java call wrapper couldn't be found
346       JavaCallWrapper *jcw = candidate.entry_frame_call_wrapper_if_safe(thread);
347       // If initial frame is frame from StubGenerator and there is no
348       // previous anchor, there are no java frames associated with a method
349       if (jcw == NULL || jcw->is_first_frame()) {
350         return false;
351       }
352     }
353 
354     if (candidate.is_interpreted_frame()) {
355       if (is_decipherable_interpreted_frame(thread, &candidate, method_p, bci_p)) {
356         *initial_frame_p = candidate;
357         return true;
358       }
359 
360       // Hopefully we got some data
361       return false;
362     }
363 
364     if (candidate.cb()->is_compiled()) {
365 
366       CompiledMethod* nm = candidate.cb()->as_compiled_method();
367       *method_p = nm->method();
368 
369       // If the frame is not decipherable, then the value of -1
370       // for the BCI is used to signal that no BCI is available.
371       // Furthermore, the method returns false in this case.
372       //
373       // If a decipherable frame is available, the BCI value will
374       // not be used.
375 
376       *bci_p = -1;
377 
378       *initial_frame_p = candidate;
379 
380       // Native wrapper code is trivial to decode by vframeStream
381 
382       if (nm->is_native_method()) return true;
383 
384       // If the frame is not decipherable, then a PC was found
385       // that does not have a PCDesc from which a BCI can be obtained.
386       // Nevertheless, a Method was found.
387 
388       if (!is_decipherable_compiled_frame(thread, &candidate, nm)) {
389         return false;
390       }
391 
392       // is_decipherable_compiled_frame may modify candidate's pc
393       *initial_frame_p = candidate;
394 
395       assert(nm->pc_desc_at(candidate.pc()) != NULL, "debug information must be available if the frame is decipherable");
396 
397       return true;
398     }
399 
400     // Must be some stub frame that we don't care about
401 
402     if (!candidate.safe_for_sender(thread)) return false;
403     candidate = candidate.sender(&map);
404 
405     // If it isn't in the code cache something is wrong
406     // since once we find a frame in the code cache they
407     // all should be there.
408 
409     if (candidate.cb() == NULL) return false;
410 
411   }
412 
413   return false;
414 
415 }
416 
417 static void forte_fill_call_trace_given_top(JavaThread* thd,
418                                             ASGCT_CallTrace* trace,
419                                             int depth,
420                                             frame top_frame) {
421   NoHandleMark nhm;
422 
423   frame initial_Java_frame;
424   Method* method;
425   int bci = -1; // assume BCI is not available for method
426                 // update with correct information if available
427   int count;
428 
429   count = 0;
430   assert(trace->frames != NULL, "trace->frames must be non-NULL");
431 
432   // Walk the stack starting from 'top_frame' and search for an initial Java frame.
433   find_initial_Java_frame(thd, &top_frame, &initial_Java_frame, &method, &bci);
434 
435   // Check if a Java Method has been found.
436   if (method == NULL) return;
437 
438   if (!Method::is_valid_method(method)) {
439     trace->num_frames = ticks_GC_active; // -2
440     return;
441   }
442 
443   vframeStreamForte st(thd, initial_Java_frame, false);
444 
445   for (; !st.at_end() && count < depth; st.forte_next(), count++) {
446     bci = st.bci();
447     method = st.method();
448 
449     if (!Method::is_valid_method(method)) {
450       // we throw away everything we've gathered in this sample since
451       // none of it is safe
452       trace->num_frames = ticks_GC_active; // -2
453       return;
454     }
455 
456     trace->frames[count].method_id = method->find_jmethod_id_or_null();
457     if (!method->is_native()) {
458       trace->frames[count].lineno = bci;
459     } else {
460       trace->frames[count].lineno = -3;
461     }
462   }
463   trace->num_frames = count;
464   return;
465 }
466 
467 
468 // Forte Analyzer AsyncGetCallTrace() entry point. Currently supported
469 // on Linux X86, Solaris SPARC and Solaris X86.
470 //
471 // Async-safe version of GetCallTrace being called from a signal handler
472 // when a LWP gets interrupted by SIGPROF but the stack traces are filled
473 // with different content (see below).
474 //
475 // This function must only be called when JVM/TI
476 // CLASS_LOAD events have been enabled since agent startup. The enabled
477 // event will cause the jmethodIDs to be allocated at class load time.
478 // The jmethodIDs cannot be allocated in a signal handler because locks
479 // cannot be grabbed in a signal handler safely.
480 //
481 // void (*AsyncGetCallTrace)(ASGCT_CallTrace *trace, jint depth, void* ucontext)
482 //
483 // Called by the profiler to obtain the current method call stack trace for
484 // a given thread. The thread is identified by the env_id field in the
485 // ASGCT_CallTrace structure. The profiler agent should allocate a ASGCT_CallTrace
486 // structure with enough memory for the requested stack depth. The VM fills in
487 // the frames buffer and the num_frames field.
488 //
489 // Arguments:
490 //
491 //   trace    - trace data structure to be filled by the VM.
492 //   depth    - depth of the call stack trace.
493 //   ucontext - ucontext_t of the LWP
494 //
495 // ASGCT_CallTrace:
496 //   typedef struct {
497 //       JNIEnv *env_id;
498 //       jint num_frames;
499 //       ASGCT_CallFrame *frames;
500 //   } ASGCT_CallTrace;
501 //
502 // Fields:
503 //   env_id     - ID of thread which executed this trace.
504 //   num_frames - number of frames in the trace.
505 //                (< 0 indicates the frame is not walkable).
506 //   frames     - the ASGCT_CallFrames that make up this trace. Callee followed by callers.
507 //
508 //  ASGCT_CallFrame:
509 //    typedef struct {
510 //        jint lineno;
511 //        jmethodID method_id;
512 //    } ASGCT_CallFrame;
513 //
514 //  Fields:
515 //    1) For Java frame (interpreted and compiled),
516 //       lineno    - bci of the method being executed or -1 if bci is not available
517 //       method_id - jmethodID of the method being executed
518 //    2) For native method
519 //       lineno    - (-3)
520 //       method_id - jmethodID of the method being executed
521 
522 extern "C" {
523 JNIEXPORT
524 void AsyncGetCallTrace(ASGCT_CallTrace *trace, jint depth, void* ucontext) {
525   JavaThread* thread;
526 
527   if (trace->env_id == NULL ||
528     (thread = JavaThread::thread_from_jni_environment(trace->env_id)) == NULL ||
529     thread->is_exiting()) {
530 
531     // bad env_id, thread has exited or thread is exiting
532     trace->num_frames = ticks_thread_exit; // -8
533     return;
534   }
535 
536   if (thread->in_deopt_handler()) {
537     // thread is in the deoptimization handler so return no frames
538     trace->num_frames = ticks_deopt; // -9
539     return;
540   }
541 
542   assert(JavaThread::current() == thread,
543          "AsyncGetCallTrace must be called by the current interrupted thread");
544 
545   if (!JvmtiExport::should_post_class_load()) {
546     trace->num_frames = ticks_no_class_load; // -1
547     return;
548   }
549 
550   if (Universe::heap()->is_gc_active()) {
551     trace->num_frames = ticks_GC_active; // -2
552     return;
553   }
554 
555   switch (thread->thread_state()) {
556   case _thread_new:
557   case _thread_uninitialized:
558   case _thread_new_trans:
559     // We found the thread on the threads list above, but it is too
560     // young to be useful so return that there are no Java frames.
561     trace->num_frames = 0;
562     break;
563   case _thread_in_native:
564   case _thread_in_native_trans:
565   case _thread_blocked:
566   case _thread_blocked_trans:
567   case _thread_in_vm:
568   case _thread_in_vm_trans:
569     {
570       frame fr;
571 
572       // param isInJava == false - indicate we aren't in Java code
573       if (!thread->pd_get_top_frame_for_signal_handler(&fr, ucontext, false)) {
574         trace->num_frames = ticks_unknown_not_Java;  // -3 unknown frame
575       } else {
576         if (!thread->has_last_Java_frame()) {
577           trace->num_frames = 0; // No Java frames
578         } else {
579           trace->num_frames = ticks_not_walkable_not_Java;    // -4 non walkable frame by default
580           forte_fill_call_trace_given_top(thread, trace, depth, fr);
581 
582           // This assert would seem to be valid but it is not.
583           // It would be valid if we weren't possibly racing a gc
584           // thread. A gc thread can make a valid interpreted frame
585           // look invalid. It's a small window but it does happen.
586           // The assert is left here commented out as a reminder.
587           // assert(trace->num_frames != ticks_not_walkable_not_Java, "should always be walkable");
588 
589         }
590       }
591     }
592     break;
593   case _thread_in_Java:
594   case _thread_in_Java_trans:
595     {
596       frame fr;
597 
598       // param isInJava == true - indicate we are in Java code
599       if (!thread->pd_get_top_frame_for_signal_handler(&fr, ucontext, true)) {
600         trace->num_frames = ticks_unknown_Java;  // -5 unknown frame
601       } else {
602         trace->num_frames = ticks_not_walkable_Java;  // -6, non walkable frame by default
603         forte_fill_call_trace_given_top(thread, trace, depth, fr);
604       }
605     }
606     break;
607   default:
608     // Unknown thread state
609     trace->num_frames = ticks_unknown_state; // -7
610     break;
611   }
612 }
613 
614 
615 #ifndef _WINDOWS
616 // Support for the Forte(TM) Peformance Tools collector.
617 //
618 // The method prototype is derived from libcollector.h. For more
619 // information, please see the libcollect man page.
620 
621 // Method to let libcollector know about a dynamically loaded function.
622 // Because it is weakly bound, the calls become NOP's when the library
623 // isn't present.
624 #ifdef __APPLE__
625 // XXXDARWIN: Link errors occur even when __attribute__((weak_import))
626 // is added
627 #define collector_func_load(x0,x1,x2,x3,x4,x5,x6) ((void) 0)
628 #else
629 void    collector_func_load(char* name,
630                             void* null_argument_1,
631                             void* null_argument_2,
632                             void *vaddr,
633                             int size,
634                             int zero_argument,
635                             void* null_argument_3);
636 #pragma weak collector_func_load
637 #define collector_func_load(x0,x1,x2,x3,x4,x5,x6) \
638         ( collector_func_load ? collector_func_load(x0,x1,x2,x3,x4,x5,x6),(void)0 : (void)0 )
639 #endif // __APPLE__
640 #endif // !_WINDOWS
641 
642 } // end extern "C"
643 #endif // !IA64
644 
645 void Forte::register_stub(const char* name, address start, address end) {
646 #if !defined(_WINDOWS) && !defined(IA64)
647   assert(pointer_delta(end, start, sizeof(jbyte)) < INT_MAX,
648          "Code size exceeds maximum range");
649 
650   collector_func_load((char*)name, NULL, NULL, start,
651     pointer_delta(end, start, sizeof(jbyte)), 0, NULL);
652 #endif // !_WINDOWS && !IA64
653 }
654 
655 #else // INCLUDE_JVMTI
656 extern "C" {
657   JNIEXPORT
658   void AsyncGetCallTrace(ASGCT_CallTrace *trace, jint depth, void* ucontext) {
659     trace->num_frames = ticks_no_class_load; // -1
660   }
661 }
662 #endif // INCLUDE_JVMTI