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 /*

  * Copyright (c) 2003, 2012, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "code/debugInfoRec.hpp"

 #include "code/pcDesc.hpp"

 #include "gc_interface/collectedHeap.inline.hpp"

 #include "memory/space.hpp"

 #include "memory/universe.inline.hpp"

 #include "oops/oop.inline.hpp"

 #include "oops/oop.inline2.hpp"

 #include "prims/forte.hpp"

 #include "runtime/thread.hpp"

 #include "runtime/vframe.hpp"

 #include "runtime/vframeArray.hpp"

 // These name match the names reported by the forte quality kit

 enum {

   ticks_no_Java_frame         =  0,

   ticks_no_class_load         = -1,

   ticks_GC_active             = -2,

   ticks_unknown_not_Java      = -3,

   ticks_not_walkable_not_Java = -4,

   ticks_unknown_Java          = -5,

   ticks_not_walkable_Java     = -6,

   ticks_unknown_state         = -7,

   ticks_thread_exit           = -8,

   ticks_deopt                 = -9,

   ticks_safepoint             = -10

 };

 //-------------------------------------------------------

 // Native interfaces for use by Forte tools.

 #ifndef IA64

 class vframeStreamForte : public vframeStreamCommon {

  public:

   // constructor that starts with sender of frame fr (top_frame)

   vframeStreamForte(JavaThread *jt, frame fr, bool stop_at_java_call_stub);

   void forte_next();

 };

 static bool is_decipherable_compiled_frame(JavaThread* thread, frame* fr, nmethod* nm);

 static bool is_decipherable_interpreted_frame(JavaThread* thread,

                                               frame* fr,

                                               Method** method_p,

                                               int* bci_p);

 vframeStreamForte::vframeStreamForte(JavaThread *jt,

                                      frame fr,

                                      bool stop_at_java_call_stub) : vframeStreamCommon(jt) {

   _stop_at_java_call_stub = stop_at_java_call_stub;

   _frame = fr;

   // We must always have a valid frame to start filling

   bool filled_in = fill_from_frame();

   assert(filled_in, "invariant");

 }

 // Solaris SPARC Compiler1 needs an additional check on the grandparent

 // of the top_frame when the parent of the top_frame is interpreted and

 // the grandparent is compiled. However, in this method we do not know

 // the relationship of the current _frame relative to the top_frame so

 // we implement a more broad sanity check. When the previous callee is

 // interpreted and the current sender is compiled, we verify that the

 // current sender is also walkable. If it is not walkable, then we mark

 // the current vframeStream as at the end.

 void vframeStreamForte::forte_next() {

   // handle frames with inlining

   if (_mode == compiled_mode &&

       vframeStreamCommon::fill_in_compiled_inlined_sender()) {

     return;

   }

   // handle general case

   int loop_count = 0;

   int loop_max = MaxJavaStackTraceDepth * 2;

   do {

     loop_count++;

     // By the time we get here we should never see unsafe but better

     // safe then segv'd

     if (loop_count > loop_max || !_frame.safe_for_sender(_thread)) {

       _mode = at_end_mode;

       return;

     }

     _frame = _frame.sender(&_reg_map);

   } while (!fill_from_frame());

 }

 // Determine if 'fr' is a decipherable compiled frame. We are already

 // assured that fr is for a java nmethod.

 static bool is_decipherable_compiled_frame(JavaThread* thread, frame* fr, nmethod* nm) {

   assert(nm->is_java_method(), "invariant");

   if (thread->has_last_Java_frame() && thread->last_Java_pc() == fr->pc()) {

     // We're stopped at a call into the JVM so look for a PcDesc with

     // the actual pc reported by the frame.

     PcDesc* pc_desc = nm->pc_desc_at(fr->pc());

     // Did we find a useful PcDesc?

     if (pc_desc != NULL &&

         pc_desc->scope_decode_offset() != DebugInformationRecorder::serialized_null) {

       return true;

     }

   }

   // We're at some random pc in the nmethod so search for the PcDesc

   // whose pc is greater than the current PC.  It's done this way

   // because the extra PcDescs that are recorded for improved debug

   // info record the end of the region covered by the ScopeDesc

   // instead of the beginning.

   PcDesc* pc_desc = nm->pc_desc_near(fr->pc() + 1);

   // Now do we have a useful PcDesc?

   if (pc_desc == NULL ||

       pc_desc->scope_decode_offset() == DebugInformationRecorder::serialized_null) {

     // No debug information available for this pc

     // vframeStream would explode if we try and walk the frames.

     return false;

   }

   // This PcDesc is useful however we must adjust the frame's pc

   // so that the vframeStream lookups will use this same pc

   fr->set_pc(pc_desc->real_pc(nm));

   return true;

 }

 // Determine if 'fr' is a walkable interpreted frame. Returns false

 // if it is not. *method_p, and *bci_p are not set when false is

 // returned. *method_p is non-NULL if frame was executing a Java

 // method. *bci_p is != -1 if a valid BCI in the Java method could

 // be found.

 // Note: this method returns true when a valid Java method is found

 // even if a valid BCI cannot be found.

 static bool is_decipherable_interpreted_frame(JavaThread* thread,

                                               frame* fr,

                                               Method** method_p,

                                               int* bci_p) {

   assert(fr->is_interpreted_frame(), "just checking");

   // top frame is an interpreted frame

   // check if it is walkable (i.e. valid Method* and valid bci)

   // Because we may be racing a gc thread the method and/or bci

   // of a valid interpreter frame may look bad causing us to

   // fail the is_interpreted_frame_valid test. If the thread

   // is in any of the following states we are assured that the

   // frame is in fact valid and we must have hit the race.

   JavaThreadState state = thread->thread_state();

   bool known_valid = (state == _thread_in_native ||

                       state == _thread_in_vm ||

                       state == _thread_blocked );

   if (known_valid || fr->is_interpreted_frame_valid(thread)) {

     // The frame code should completely validate the frame so that

     // references to Method* and bci are completely safe to access

     // If they aren't the frame code should be fixed not this

     // code. However since gc isn't locked out the values could be

     // stale. This is a race we can never completely win since we can't

     // lock out gc so do one last check after retrieving their values

     // from the frame for additional safety

     Method* method = fr->interpreter_frame_method();

     // We've at least found a method.

     // NOTE: there is something to be said for the approach that

     // if we don't find a valid bci then the method is not likely

     // a valid method. Then again we may have caught an interpreter

     // frame in the middle of construction and the bci field is

     // not yet valid.

     *method_p = method;

     // See if gc may have invalidated method since we validated frame

     if (!Universe::heap()->is_valid_method(method)) return false;

     intptr_t bcx = fr->interpreter_frame_bcx();

     int      bci = method->validate_bci_from_bcx(bcx);

     // note: bci is set to -1 if not a valid bci

     *bci_p = bci;

     return true;

   }

   return false;

 }

 // Determine if 'fr' can be used to find an initial Java frame.

 // Return false if it can not find a fully decipherable Java frame

 // (in other words a frame that isn't safe to use in a vframe stream).

 // Obviously if it can't even find a Java frame false will also be returned.

 //

 // If we find a Java frame decipherable or not then by definition we have

 // identified a method and that will be returned to the caller via method_p.

 // If we can determine a bci that is returned also. (Hmm is it possible

 // to return a method and bci and still return false? )

 //

 // The initial Java frame we find (if any) is return via initial_frame_p.

 //

 static bool find_initial_Java_frame(JavaThread* thread,

                                     frame* fr,

                                     frame* initial_frame_p,

                                     Method** method_p,

                                     int* bci_p) {

   // It is possible that for a frame containing an nmethod

   // we can capture the method but no bci. If we get no

   // bci the frame isn't walkable but the method is usable.

   // Therefore we init the returned Method* to NULL so the

   // caller can make the distinction.

   *method_p = NULL;

   // On the initial call to this method the frame we get may not be

   // recognizable to us. This should only happen if we are in a JRT_LEAF

   // or something called by a JRT_LEAF method.

   frame candidate = *fr;

   // If the starting frame we were given has no codeBlob associated with

   // it see if we can find such a frame because only frames with codeBlobs

   // are possible Java frames.

   if (fr->cb() == NULL) {

     // See if we can find a useful frame

     int loop_count;

     int loop_max = MaxJavaStackTraceDepth * 2;

     RegisterMap map(thread, false);

     for (loop_count = 0; loop_count < loop_max; loop_count++) {

       if (!candidate.safe_for_sender(thread)) return false;

       candidate = candidate.sender(&map);

       if (candidate.cb() != NULL) break;

     }

     if (candidate.cb() == NULL) return false;

   }

   // We have a frame known to be in the codeCache

   // We will hopefully be able to figure out something to do with it.

   int loop_count;

   int loop_max = MaxJavaStackTraceDepth * 2;

   RegisterMap map(thread, false);

   for (loop_count = 0; loop_count < loop_max; loop_count++) {

     if (candidate.is_first_frame()) {

       // If initial frame is frame from StubGenerator and there is no

       // previous anchor, there are no java frames associated with a method

       return false;

     }

     if (candidate.is_interpreted_frame()) {

       if (is_decipherable_interpreted_frame(thread, &candidate, method_p, bci_p)) {

         *initial_frame_p = candidate;

         return true;

       }

       // Hopefully we got some data

       return false;

     }

     if (candidate.cb()->is_nmethod()) {

       nmethod* nm = (nmethod*) candidate.cb();

       *method_p = nm->method();

       // If the frame isn't fully decipherable then the default

       // value for the bci is a signal that we don't have a bci.

       // If we have a decipherable frame this bci value will

       // not be used.

       *bci_p = -1;

       *initial_frame_p = candidate;

       // Native wrapper code is trivial to decode by vframeStream

       if (nm->is_native_method()) return true;

       // If it isn't decipherable then we have found a pc that doesn't

       // have a PCDesc that can get us a bci however we did find

       // a method

       if (!is_decipherable_compiled_frame(thread, &candidate, nm)) {

         return false;

       }

       // is_decipherable_compiled_frame may modify candidate's pc

       *initial_frame_p = candidate;

       assert(nm->pc_desc_at(candidate.pc()) != NULL, "if it's decipherable then pc must be valid");

       return true;

     }

     // Must be some stub frame that we don't care about

     if (!candidate.safe_for_sender(thread)) return false;

     candidate = candidate.sender(&map);

     // If it isn't in the code cache something is wrong

     // since once we find a frame in the code cache they

     // all should be there.

     if (candidate.cb() == NULL) return false;

   }

   return false;

 }

 // call frame copied from old .h file and renamed

 typedef struct {

     jint lineno;                      // line number in the source file

     jmethodID method_id;              // method executed in this frame

 } ASGCT_CallFrame;

 // call trace copied from old .h file and renamed

 typedef struct {

     JNIEnv *env_id;                   // Env where trace was recorded

     jint num_frames;                  // number of frames in this trace

     ASGCT_CallFrame *frames;          // frames

 } ASGCT_CallTrace;

 static void forte_fill_call_trace_given_top(JavaThread* thd,

                                             ASGCT_CallTrace* trace,

                                             int depth,

                                             frame top_frame) {

   NoHandleMark nhm;

   frame initial_Java_frame;

   Method* method;

   int bci;

   int count;

   count = 0;

   assert(trace->frames != NULL, "trace->frames must be non-NULL");

   bool fully_decipherable = find_initial_Java_frame(thd, &top_frame, &initial_Java_frame, &method, &bci);

   // The frame might not be walkable but still recovered a method

   // (e.g. an nmethod with no scope info for the pc

   if (method == NULL) return;

   CollectedHeap* ch = Universe::heap();

   // The method is not stored GC safe so see if GC became active

   // after we entered AsyncGetCallTrace() and before we try to

   // use the Method*.

   // Yes, there is still a window after this check and before

   // we use Method* below, but we can't lock out GC so that

   // has to be an acceptable risk.

   if (!ch->is_valid_method(method)) {

     trace->num_frames = ticks_GC_active; // -2

     return;

   }

   // We got a Java frame however it isn't fully decipherable

   // so it won't necessarily be safe to use it for the

   // initial frame in the vframe stream.

   if (!fully_decipherable) {

     // Take whatever method the top-frame decoder managed to scrape up.

     // We look further at the top frame only if non-safepoint

     // debugging information is available.

     count++;

     trace->num_frames = count;

     trace->frames[0].method_id = method->find_jmethod_id_or_null();

     if (!method->is_native()) {

       trace->frames[0].lineno = bci;

     } else {

       trace->frames[0].lineno = -3;

     }

     if (!initial_Java_frame.safe_for_sender(thd)) return;

     RegisterMap map(thd, false);

     initial_Java_frame = initial_Java_frame.sender(&map);

   }

   vframeStreamForte st(thd, initial_Java_frame, false);

   for (; !st.at_end() && count < depth; st.forte_next(), count++) {

     bci = st.bci();

     method = st.method();

     // The method is not stored GC safe so see if GC became active

     // after we entered AsyncGetCallTrace() and before we try to

     // use the Method*.

     // Yes, there is still a window after this check and before

     // we use Method* below, but we can't lock out GC so that

     // has to be an acceptable risk.

     if (!ch->is_valid_method(method)) {

       // we throw away everything we've gathered in this sample since

       // none of it is safe

       trace->num_frames = ticks_GC_active; // -2

       return;

     }

     trace->frames[count].method_id = method->find_jmethod_id_or_null();

     if (!method->is_native()) {

       trace->frames[count].lineno = bci;

     } else {

       trace->frames[count].lineno = -3;

     }

   }

   trace->num_frames = count;

   return;

 }

 // Forte Analyzer AsyncGetCallTrace() entry point. Currently supported

 // on Linux X86, Solaris SPARC and Solaris X86.

 //

 // Async-safe version of GetCallTrace being called from a signal handler

 // when a LWP gets interrupted by SIGPROF but the stack traces are filled

 // with different content (see below).

 //

 // This function must only be called when JVM/TI

 // CLASS_LOAD events have been enabled since agent startup. The enabled

 // event will cause the jmethodIDs to be allocated at class load time.

 // The jmethodIDs cannot be allocated in a signal handler because locks

 // cannot be grabbed in a signal handler safely.

 //

 // void (*AsyncGetCallTrace)(ASGCT_CallTrace *trace, jint depth, void* ucontext)

 //

 // Called by the profiler to obtain the current method call stack trace for

 // a given thread. The thread is identified by the env_id field in the

 // ASGCT_CallTrace structure. The profiler agent should allocate a ASGCT_CallTrace

 // structure with enough memory for the requested stack depth. The VM fills in

 // the frames buffer and the num_frames field.

 //

 // Arguments:

 //

 //   trace    - trace data structure to be filled by the VM.

 //   depth    - depth of the call stack trace.

 //   ucontext - ucontext_t of the LWP

 //

 // ASGCT_CallTrace:

 //   typedef struct {

 //       JNIEnv *env_id;

 //       jint num_frames;

 //       ASGCT_CallFrame *frames;

 //   } ASGCT_CallTrace;

 //

 // Fields:

 //   env_id     - ID of thread which executed this trace.

 //   num_frames - number of frames in the trace.

 //                (< 0 indicates the frame is not walkable).

 //   frames     - the ASGCT_CallFrames that make up this trace. Callee followed by callers.

 //

 //  ASGCT_CallFrame:

 //    typedef struct {

 //        jint lineno;

 //        jmethodID method_id;

 //    } ASGCT_CallFrame;

 //

 //  Fields:

 //    1) For Java frame (interpreted and compiled),

 //       lineno    - bci of the method being executed or -1 if bci is not available

 //       method_id - jmethodID of the method being executed

 //    2) For native method

 //       lineno    - (-3)

 //       method_id - jmethodID of the method being executed

 extern "C" {

 JNIEXPORT

 void AsyncGetCallTrace(ASGCT_CallTrace *trace, jint depth, void* ucontext) {

   JavaThread* thread;

   if (trace->env_id == NULL ||

     (thread = JavaThread::thread_from_jni_environment(trace->env_id)) == NULL ||

     thread->is_exiting()) {

     // bad env_id, thread has exited or thread is exiting

     trace->num_frames = ticks_thread_exit; // -8

     return;

   }

   if (thread->in_deopt_handler()) {

     // thread is in the deoptimization handler so return no frames

     trace->num_frames = ticks_deopt; // -9

     return;

   }

   assert(JavaThread::current() == thread,

          "AsyncGetCallTrace must be called by the current interrupted thread");

   if (!JvmtiExport::should_post_class_load()) {

     trace->num_frames = ticks_no_class_load; // -1

     return;

   }

   if (Universe::heap()->is_gc_active()) {

     trace->num_frames = ticks_GC_active; // -2

     return;

   }

   switch (thread->thread_state()) {

   case _thread_new:

   case _thread_uninitialized:

   case _thread_new_trans:

     // We found the thread on the threads list above, but it is too

     // young to be useful so return that there are no Java frames.

     trace->num_frames = 0;

     break;

   case _thread_in_native:

   case _thread_in_native_trans:

   case _thread_blocked:

   case _thread_blocked_trans:

   case _thread_in_vm:

   case _thread_in_vm_trans:

     {

       frame fr;

       // param isInJava == false - indicate we aren't in Java code

       if (!thread->pd_get_top_frame_for_signal_handler(&fr, ucontext, false)) {

         trace->num_frames = ticks_unknown_not_Java;  // -3 unknown frame

       } else {

         if (!thread->has_last_Java_frame()) {

           trace->num_frames = 0; // No Java frames

         } else {

           trace->num_frames = ticks_not_walkable_not_Java;    // -4 non walkable frame by default

           forte_fill_call_trace_given_top(thread, trace, depth, fr);

           // This assert would seem to be valid but it is not.

           // It would be valid if we weren't possibly racing a gc

           // thread. A gc thread can make a valid interpreted frame

           // look invalid. It's a small window but it does happen.

           // The assert is left here commented out as a reminder.

           // assert(trace->num_frames != ticks_not_walkable_not_Java, "should always be walkable");

         }

       }

     }

     break;

   case _thread_in_Java:

   case _thread_in_Java_trans:

     {

       frame fr;

       // param isInJava == true - indicate we are in Java code

       if (!thread->pd_get_top_frame_for_signal_handler(&fr, ucontext, true)) {

         trace->num_frames = ticks_unknown_Java;  // -5 unknown frame

       } else {

         trace->num_frames = ticks_not_walkable_Java;  // -6, non walkable frame by default

         forte_fill_call_trace_given_top(thread, trace, depth, fr);

       }

     }

     break;

   default:

     // Unknown thread state

     trace->num_frames = ticks_unknown_state; // -7

     break;

   }

 }

 #ifndef _WINDOWS

 // Support for the Forte(TM) Peformance Tools collector.

 //

 // The method prototype is derived from libcollector.h. For more

 // information, please see the libcollect man page.

 // Method to let libcollector know about a dynamically loaded function.

 // Because it is weakly bound, the calls become NOP's when the library

 // isn't present.

 #ifdef __APPLE__

 // XXXDARWIN: Link errors occur even when __attribute__((weak_import))

 // is added

 #define collector_func_load(x0,x1,x2,x3,x4,x5,x6) (0)

 #else

 void    collector_func_load(char* name,

                             void* null_argument_1,

                             void* null_argument_2,

                             void *vaddr,

                             int size,

                             int zero_argument,

                             void* null_argument_3);

 #pragma weak collector_func_load

 #define collector_func_load(x0,x1,x2,x3,x4,x5,x6) \

         ( collector_func_load ? collector_func_load(x0,x1,x2,x3,x4,x5,x6),0 : 0 )

 #endif // __APPLE__

 #endif // !_WINDOWS

 } // end extern "C"

 #endif // !IA64

 void Forte::register_stub(const char* name, address start, address end) {

 #if !defined(_WINDOWS) && !defined(IA64)

   assert(pointer_delta(end, start, sizeof(jbyte)) < INT_MAX,

          "Code size exceeds maximum range");

   collector_func_load((char*)name, NULL, NULL, start,

     pointer_delta(end, start, sizeof(jbyte)), 0, NULL);

 #endif // !_WINDOWS && !IA64

 }