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changeset 9782:9ffa0d7ed932 jdk8u141-b31

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8161598: Kitchensink fails: assert(nm->insts_contains(original_pc)) failed: original PC must be in nmethod/CompiledMethod Reviewed-by: dlong
author kevinw
date Mon, 26 Jun 2017 02:04:40 -0700
parents 6470230caf2a
children 7625d5f8ebc1
files src/cpu/x86/vm/c1_Runtime1_x86.cpp src/cpu/x86/vm/frame_x86.cpp src/cpu/x86/vm/frame_x86.inline.hpp src/cpu/x86/vm/javaFrameAnchor_x86.hpp src/cpu/x86/vm/macroAssembler_x86.cpp src/cpu/x86/vm/macroAssembler_x86.hpp src/cpu/x86/vm/runtime_x86_32.cpp src/cpu/x86/vm/sharedRuntime_x86_32.cpp src/cpu/x86/vm/sharedRuntime_x86_64.cpp src/cpu/x86/vm/stubGenerator_x86_32.cpp src/cpu/x86/vm/stubGenerator_x86_64.cpp src/cpu/x86/vm/templateInterpreter_x86_32.cpp src/cpu/x86/vm/templateInterpreter_x86_64.cpp src/os_cpu/bsd_x86/vm/thread_bsd_x86.cpp src/os_cpu/bsd_x86/vm/thread_bsd_x86.hpp src/os_cpu/linux_x86/vm/thread_linux_x86.cpp src/os_cpu/linux_x86/vm/thread_linux_x86.hpp src/os_cpu/solaris_x86/vm/thread_solaris_x86.cpp src/os_cpu/solaris_x86/vm/thread_solaris_x86.hpp src/os_cpu/windows_x86/vm/thread_windows_x86.cpp src/os_cpu/windows_x86/vm/thread_windows_x86.hpp
diffstat 21 files changed, 78 insertions(+), 76 deletions(-) [+]
line wrap: on
line diff
--- a/src/cpu/x86/vm/c1_Runtime1_x86.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/c1_Runtime1_x86.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -98,7 +98,7 @@
   }
   pop(rax);
 #endif
-  reset_last_Java_frame(thread, true, align_stack);
+  reset_last_Java_frame(thread, true);
 
   // discard thread and arguments
   NOT_LP64(addptr(rsp, num_rt_args()*BytesPerWord));
@@ -882,7 +882,7 @@
   }
   __ pop(rax);
 #endif
-  __ reset_last_Java_frame(thread, true, false);
+  __ reset_last_Java_frame(thread, true);
 #ifndef _LP64
   __ pop(rcx); // discard thread arg
   __ pop(rcx); // discard dummy
--- a/src/cpu/x86/vm/frame_x86.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/frame_x86.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -370,13 +370,16 @@
   JavaFrameAnchor* jfa = entry_frame_call_wrapper()->anchor();
   assert(!entry_frame_is_first(), "next Java fp must be non zero");
   assert(jfa->last_Java_sp() > sp(), "must be above this frame on stack");
+  // Since we are walking the stack now this nested anchor is obviously walkable
+  // even if it wasn't when it was stacked.
+  if (!jfa->walkable()) {
+    // Capture _last_Java_pc (if needed) and mark anchor walkable.
+    jfa->capture_last_Java_pc();
+  }
   map->clear();
   assert(map->include_argument_oops(), "should be set by clear");
-  if (jfa->last_Java_pc() != NULL ) {
-    frame fr(jfa->last_Java_sp(), jfa->last_Java_fp(), jfa->last_Java_pc());
-    return fr;
-  }
-  frame fr(jfa->last_Java_sp(), jfa->last_Java_fp());
+  assert(jfa->last_Java_pc() != NULL, "not walkable");
+  frame fr(jfa->last_Java_sp(), jfa->last_Java_fp(), jfa->last_Java_pc());
   return fr;
 }
 
@@ -714,3 +717,21 @@
   init((intptr_t*)sp, (intptr_t*)fp, (address)pc);
 }
 #endif
+
+void JavaFrameAnchor::make_walkable(JavaThread* thread) {
+  // last frame set?
+  if (last_Java_sp() == NULL) return;
+  // already walkable?
+  if (walkable()) return;
+  assert(Thread::current() == (Thread*)thread, "not current thread");
+  assert(last_Java_sp() != NULL, "not called from Java code?");
+  assert(last_Java_pc() == NULL, "already walkable");
+  capture_last_Java_pc();
+  assert(walkable(), "something went wrong");
+}
+
+void JavaFrameAnchor::capture_last_Java_pc() {
+  assert(_last_Java_sp != NULL, "no last frame set");
+  assert(_last_Java_pc == NULL, "already walkable");
+  _last_Java_pc = (address)_last_Java_sp[-1];
+}
--- a/src/cpu/x86/vm/frame_x86.inline.hpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/frame_x86.inline.hpp	Mon Jun 26 02:04:40 2017 -0700
@@ -96,6 +96,7 @@
   // call a specialized frame constructor instead of this one.
   // Then we could use the assert below. However this assert is of somewhat dubious
   // value.
+  // UPDATE: this constructor is only used by trace_method_handle_stub() now.
   // assert(_pc != NULL, "no pc?");
 
   _cb = CodeCache::find_blob(_pc);
--- a/src/cpu/x86/vm/javaFrameAnchor_x86.hpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/javaFrameAnchor_x86.hpp	Mon Jun 26 02:04:40 2017 -0700
@@ -62,10 +62,9 @@
     _last_Java_sp = src->_last_Java_sp;
   }
 
-  // Always walkable
-  bool walkable(void) { return true; }
-  // Never any thing to do since we are always walkable and can find address of return addresses
-  void make_walkable(JavaThread* thread) { }
+  bool walkable(void)                            { return _last_Java_sp != NULL && _last_Java_pc != NULL; }
+  void make_walkable(JavaThread* thread);
+  void capture_last_Java_pc(void);
 
   intptr_t* last_Java_sp(void) const             { return _last_Java_sp; }
 
--- a/src/cpu/x86/vm/macroAssembler_x86.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/macroAssembler_x86.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -748,8 +748,7 @@
   }
 }
 
-void MacroAssembler::reset_last_Java_frame(bool clear_fp,
-                                           bool clear_pc) {
+void MacroAssembler::reset_last_Java_frame(bool clear_fp) {
   // we must set sp to zero to clear frame
   movptr(Address(r15_thread, JavaThread::last_Java_sp_offset()), NULL_WORD);
   // must clear fp, so that compiled frames are not confused; it is
@@ -758,9 +757,8 @@
     movptr(Address(r15_thread, JavaThread::last_Java_fp_offset()), NULL_WORD);
   }
 
-  if (clear_pc) {
-    movptr(Address(r15_thread, JavaThread::last_Java_pc_offset()), NULL_WORD);
-  }
+  // Always clear the pc because it could have been set by make_walkable()
+  movptr(Address(r15_thread, JavaThread::last_Java_pc_offset()), NULL_WORD);
 }
 
 void MacroAssembler::set_last_Java_frame(Register last_java_sp,
@@ -2561,7 +2559,7 @@
   }
   // reset last Java frame
   // Only interpreter should have to clear fp
-  reset_last_Java_frame(java_thread, true, false);
+  reset_last_Java_frame(java_thread, true);
 
 #ifndef CC_INTERP
    // C++ interp handles this in the interpreter
@@ -3808,7 +3806,7 @@
   pusha();
 }
 
-void MacroAssembler::reset_last_Java_frame(Register java_thread, bool clear_fp, bool clear_pc) {
+void MacroAssembler::reset_last_Java_frame(Register java_thread, bool clear_fp) {
   // determine java_thread register
   if (!java_thread->is_valid()) {
     java_thread = rdi;
@@ -3820,8 +3818,8 @@
     movptr(Address(java_thread, JavaThread::last_Java_fp_offset()), NULL_WORD);
   }
 
-  if (clear_pc)
-    movptr(Address(java_thread, JavaThread::last_Java_pc_offset()), NULL_WORD);
+  // Always clear the pc because it could have been set by make_walkable()
+  movptr(Address(java_thread, JavaThread::last_Java_pc_offset()), NULL_WORD);
 
 }
 
--- a/src/cpu/x86/vm/macroAssembler_x86.hpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/macroAssembler_x86.hpp	Mon Jun 26 02:04:40 2017 -0700
@@ -289,10 +289,10 @@
                            Register last_java_fp,
                            address last_java_pc);
 
-  void reset_last_Java_frame(Register thread, bool clear_fp, bool clear_pc);
+  void reset_last_Java_frame(Register thread, bool clear_fp);
 
   // thread in the default location (r15_thread on 64bit)
-  void reset_last_Java_frame(bool clear_fp, bool clear_pc);
+  void reset_last_Java_frame(bool clear_fp);
 
   // Stores
   void store_check(Register obj);                // store check for obj - register is destroyed afterwards
--- a/src/cpu/x86/vm/runtime_x86_32.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/runtime_x86_32.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -116,7 +116,7 @@
   // No registers to map, rbp is known implicitly
   oop_maps->add_gc_map( __ pc() - start,  new OopMap( framesize, 0 ));
   __ get_thread(rcx);
-  __ reset_last_Java_frame(rcx, false, false);
+  __ reset_last_Java_frame(rcx, false);
 
   // Restore callee-saved registers
   __ movptr(rbp, Address(rsp, rbp_off * wordSize));
--- a/src/cpu/x86/vm/sharedRuntime_x86_32.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/sharedRuntime_x86_32.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -1333,7 +1333,7 @@
   __ increment(rsp, wordSize);
 
   __ get_thread(thread);
-  __ reset_last_Java_frame(thread, false, true);
+  __ reset_last_Java_frame(thread, false);
 
   save_or_restore_arguments(masm, stack_slots, total_in_args,
                             arg_save_area, NULL, in_regs, in_sig_bt);
@@ -2251,7 +2251,7 @@
 
   // We can finally stop using that last_Java_frame we setup ages ago
 
-  __ reset_last_Java_frame(thread, false, true);
+  __ reset_last_Java_frame(thread, false);
 
   // Unpack oop result
   if (ret_type == T_OBJECT || ret_type == T_ARRAY) {
@@ -2951,7 +2951,7 @@
   __ pop(rcx);
 
   __ get_thread(rcx);
-  __ reset_last_Java_frame(rcx, false, false);
+  __ reset_last_Java_frame(rcx, false);
 
   // Load UnrollBlock into EDI
   __ mov(rdi, rax);
@@ -3117,7 +3117,7 @@
   __ push(rax);
 
   __ get_thread(rcx);
-  __ reset_last_Java_frame(rcx, false, false);
+  __ reset_last_Java_frame(rcx, false);
 
   // Collect return values
   __ movptr(rax,Address(rsp, (RegisterSaver::raxOffset() + additional_words + 1)*wordSize));
@@ -3219,7 +3219,7 @@
 
   __ get_thread(rcx);
 
-  __ reset_last_Java_frame(rcx, false, false);
+  __ reset_last_Java_frame(rcx, false);
 
   // Load UnrollBlock into EDI
   __ movptr(rdi, rax);
@@ -3331,7 +3331,7 @@
   oop_maps->add_gc_map( __ pc()-start, new OopMap( framesize, 0 ) );
 
   __ get_thread(rdi);
-  __ reset_last_Java_frame(rdi, true, false);
+  __ reset_last_Java_frame(rdi, true);
 
   // Pop self-frame.
   __ leave();     // Epilog!
@@ -3426,7 +3426,7 @@
 
   // Clear last_Java_sp again
   __ get_thread(java_thread);
-  __ reset_last_Java_frame(java_thread, false, false);
+  __ reset_last_Java_frame(java_thread, false);
 
   __ cmpptr(Address(java_thread, Thread::pending_exception_offset()), (int32_t)NULL_WORD);
   __ jcc(Assembler::equal, noException);
@@ -3501,7 +3501,7 @@
   __ addptr(rsp, wordSize);
 
   // clear last_Java_sp
-  __ reset_last_Java_frame(thread, true, false);
+  __ reset_last_Java_frame(thread, true);
   // check for pending exceptions
   Label pending;
   __ cmpptr(Address(thread, Thread::pending_exception_offset()), (int32_t)NULL_WORD);
--- a/src/cpu/x86/vm/sharedRuntime_x86_64.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/sharedRuntime_x86_64.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -1388,7 +1388,7 @@
   __ mov(rsp, r12); // restore sp
   __ reinit_heapbase();
 
-  __ reset_last_Java_frame(false, true);
+  __ reset_last_Java_frame(false);
 
   save_or_restore_arguments(masm, stack_slots, total_in_args,
                             arg_save_area, NULL, in_regs, in_sig_bt);
@@ -2497,7 +2497,7 @@
     restore_native_result(masm, ret_type, stack_slots);
   }
 
-  __ reset_last_Java_frame(false, true);
+  __ reset_last_Java_frame(false);
 
   // Unpack oop result
   if (ret_type == T_OBJECT || ret_type == T_ARRAY) {
@@ -3435,7 +3435,7 @@
   // find any register it might need.
   oop_maps->add_gc_map(__ pc() - start, map);
 
-  __ reset_last_Java_frame(false, false);
+  __ reset_last_Java_frame(false);
 
   // Load UnrollBlock* into rdi
   __ mov(rdi, rax);
@@ -3592,7 +3592,7 @@
                        new OopMap( frame_size_in_words, 0 ));
 
   // Clear fp AND pc
-  __ reset_last_Java_frame(true, true);
+  __ reset_last_Java_frame(true);
 
   // Collect return values
   __ movdbl(xmm0, Address(rsp, RegisterSaver::xmm0_offset_in_bytes()));
@@ -3662,7 +3662,7 @@
 
   oop_maps->add_gc_map(__ pc() - start, map);
 
-  __ reset_last_Java_frame(false, false);
+  __ reset_last_Java_frame(false);
 
   // Load UnrollBlock* into rdi
   __ mov(rdi, rax);
@@ -3775,7 +3775,7 @@
   oop_maps->add_gc_map(the_pc - start, new OopMap(SimpleRuntimeFrame::framesize, 0));
 
   // Clear fp AND pc
-  __ reset_last_Java_frame(true, true);
+  __ reset_last_Java_frame(true);
 
   // Pop self-frame.
   __ leave();                 // Epilog
@@ -3858,7 +3858,7 @@
 
   Label noException;
 
-  __ reset_last_Java_frame(false, false);
+  __ reset_last_Java_frame(false);
 
   __ cmpptr(Address(r15_thread, Thread::pending_exception_offset()), (int32_t)NULL_WORD);
   __ jcc(Assembler::equal, noException);
@@ -3928,7 +3928,7 @@
   // rax contains the address we are going to jump to assuming no exception got installed
 
   // clear last_Java_sp
-  __ reset_last_Java_frame(false, false);
+  __ reset_last_Java_frame(false);
   // check for pending exceptions
   Label pending;
   __ cmpptr(Address(r15_thread, Thread::pending_exception_offset()), (int32_t)NULL_WORD);
@@ -4309,7 +4309,7 @@
 
   oop_maps->add_gc_map(the_pc - start, new OopMap(SimpleRuntimeFrame::framesize, 0));
 
-  __ reset_last_Java_frame(false, true);
+  __ reset_last_Java_frame(false);
 
   // Restore callee-saved registers
 
--- a/src/cpu/x86/vm/stubGenerator_x86_32.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/stubGenerator_x86_32.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -2901,7 +2901,7 @@
     // however can use the register value directly if it is callee saved.
     __ get_thread(java_thread);
 
-    __ reset_last_Java_frame(java_thread, true, false);
+    __ reset_last_Java_frame(java_thread, true);
 
     __ leave(); // required for proper stackwalking of RuntimeStub frame
 
--- a/src/cpu/x86/vm/stubGenerator_x86_64.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/stubGenerator_x86_64.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -3923,7 +3923,7 @@
 
     oop_maps->add_gc_map(the_pc - start, map);
 
-    __ reset_last_Java_frame(true, true);
+    __ reset_last_Java_frame(true);
 
     __ leave(); // required for proper stackwalking of RuntimeStub frame
 
--- a/src/cpu/x86/vm/templateInterpreter_x86_32.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/templateInterpreter_x86_32.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -1289,7 +1289,7 @@
   // change thread state
   __ movl(Address(thread, JavaThread::thread_state_offset()), _thread_in_Java);
 
-  __ reset_last_Java_frame(thread, true, true);
+  __ reset_last_Java_frame(thread, true);
 
   // reset handle block
   __ movptr(t, Address(thread, JavaThread::active_handles_offset()));
@@ -1819,7 +1819,7 @@
   __ set_last_Java_frame(thread, noreg, rbp, __ pc());
   __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, InterpreterRuntime::popframe_move_outgoing_args), thread, rax, rbx);
   __ get_thread(thread);
-  __ reset_last_Java_frame(thread, true, true);
+  __ reset_last_Java_frame(thread, true);
   // Restore the last_sp and null it out
   __ movptr(rsp, Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize));
   __ movptr(Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize), NULL_WORD);
--- a/src/cpu/x86/vm/templateInterpreter_x86_64.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/cpu/x86/vm/templateInterpreter_x86_64.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -1262,7 +1262,7 @@
   __ movl(Address(r15_thread, JavaThread::thread_state_offset()), _thread_in_Java);
 
   // reset_last_Java_frame
-  __ reset_last_Java_frame(true, true);
+  __ reset_last_Java_frame(r15_thread, true);
 
   // reset handle block
   __ movptr(t, Address(r15_thread, JavaThread::active_handles_offset()));
@@ -1837,7 +1837,7 @@
   // PC must point into interpreter here
   __ set_last_Java_frame(noreg, rbp, __ pc());
   __ super_call_VM_leaf(CAST_FROM_FN_PTR(address, InterpreterRuntime::popframe_move_outgoing_args), r15_thread, c_rarg1, c_rarg2);
-  __ reset_last_Java_frame(true, true);
+  __ reset_last_Java_frame(r15_thread, true);
   // Restore the last_sp and null it out
   __ movptr(rsp, Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize));
   __ movptr(Address(rbp, frame::interpreter_frame_last_sp_offset * wordSize), (int32_t)NULL_WORD);
--- a/src/os_cpu/bsd_x86/vm/thread_bsd_x86.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/os_cpu/bsd_x86/vm/thread_bsd_x86.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -44,7 +44,7 @@
 
   // If we have a last_Java_frame, then we should use it even if
   // isInJava == true.  It should be more reliable than ucontext info.
-  if (jt->has_last_Java_frame()) {
+  if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {
     *fr_addr = jt->pd_last_frame();
     return true;
   }
--- a/src/os_cpu/bsd_x86/vm/thread_bsd_x86.hpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/os_cpu/bsd_x86/vm/thread_bsd_x86.hpp	Mon Jun 26 02:04:40 2017 -0700
@@ -32,12 +32,8 @@
 
   frame pd_last_frame() {
     assert(has_last_Java_frame(), "must have last_Java_sp() when suspended");
-    if (_anchor.last_Java_pc() != NULL) {
-      return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp(), _anchor.last_Java_pc());
-    } else {
-      // This will pick up pc from sp
-      return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp());
-    }
+    assert(_anchor.last_Java_pc() != NULL, "not walkable");
+    return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp(), _anchor.last_Java_pc());
   }
 
  public:
--- a/src/os_cpu/linux_x86/vm/thread_linux_x86.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/os_cpu/linux_x86/vm/thread_linux_x86.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -45,7 +45,7 @@
 
   // If we have a last_Java_frame, then we should use it even if
   // isInJava == true.  It should be more reliable than ucontext info.
-  if (jt->has_last_Java_frame()) {
+  if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {
     *fr_addr = jt->pd_last_frame();
     return true;
   }
--- a/src/os_cpu/linux_x86/vm/thread_linux_x86.hpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/os_cpu/linux_x86/vm/thread_linux_x86.hpp	Mon Jun 26 02:04:40 2017 -0700
@@ -32,12 +32,8 @@
 
   frame pd_last_frame() {
     assert(has_last_Java_frame(), "must have last_Java_sp() when suspended");
-    if (_anchor.last_Java_pc() != NULL) {
-      return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp(), _anchor.last_Java_pc());
-    } else {
-      // This will pick up pc from sp
-      return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp());
-    }
+    assert(_anchor.last_Java_pc() != NULL, "not walkable");
+    return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp(), _anchor.last_Java_pc());
   }
 
  public:
--- a/src/os_cpu/solaris_x86/vm/thread_solaris_x86.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/os_cpu/solaris_x86/vm/thread_solaris_x86.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -44,9 +44,8 @@
   assert(this->is_Java_thread(), "must be JavaThread");
   JavaThread* jt = (JavaThread *)this;
 
-  // last_Java_frame is always walkable and safe use it if we have it
-
-  if (jt->has_last_Java_frame()) {
+  // There is small window where last_Java_frame is not walkable or safe
+  if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {
     *fr_addr = jt->pd_last_frame();
     return true;
   }
--- a/src/os_cpu/solaris_x86/vm/thread_solaris_x86.hpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/os_cpu/solaris_x86/vm/thread_solaris_x86.hpp	Mon Jun 26 02:04:40 2017 -0700
@@ -30,12 +30,8 @@
 
   frame pd_last_frame() {
     assert(has_last_Java_frame(), "must have last_Java_sp() when suspended");
-    if (_anchor.last_Java_pc() != NULL) {
-      return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp(), _anchor.last_Java_pc());
-    } else {
-      // This will pick up pc from sp
-      return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp());
-    }
+    assert(_anchor.last_Java_pc() != NULL, "not walkable");
+    return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp(), _anchor.last_Java_pc());
   }
 
  public:
--- a/src/os_cpu/windows_x86/vm/thread_windows_x86.cpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/os_cpu/windows_x86/vm/thread_windows_x86.cpp	Mon Jun 26 02:04:40 2017 -0700
@@ -47,7 +47,7 @@
 
   // If we have a last_Java_frame, then we should use it even if
   // isInJava == true.  It should be more reliable than CONTEXT info.
-  if (jt->has_last_Java_frame()) {
+  if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {
     *fr_addr = jt->pd_last_frame();
     return true;
   }
--- a/src/os_cpu/windows_x86/vm/thread_windows_x86.hpp	Mon Jun 19 22:49:52 2017 +0000
+++ b/src/os_cpu/windows_x86/vm/thread_windows_x86.hpp	Mon Jun 26 02:04:40 2017 -0700
@@ -32,12 +32,8 @@
 
   frame pd_last_frame() {
     assert(has_last_Java_frame(), "must have last_Java_sp() when suspended");
-    if (_anchor.last_Java_pc() != NULL) {
-      return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp(), _anchor.last_Java_pc());
-    } else {
-      // This will pick up pc from sp
-      return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp());
-    }
+    assert(_anchor.last_Java_pc() != NULL, "not walkable");
+    return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp(), _anchor.last_Java_pc());
   }
 
  public: