506      // dumping last frame with frame::describe
 507 
 508       JavaThread* p = JavaThread::active();
 509 
 510       ResourceMark rm;
 511       PRESERVE_EXCEPTION_MARK; // may not be needed by safer and unexpensive here
 512       FrameValues values;
 513 
 514       // Note: We want to allow trace_method_handle from any call site.
 515       // While trace_method_handle creates a frame, it may be entered
 516       // without a PC on the stack top (e.g. not just after a call).
 517       // Walking that frame could lead to failures due to that invalid PC.
 518       // => carefully detect that frame when doing the stack walking
 519 
 520       // Current C frame
 521       frame cur_frame = os::current_frame();
 522 
 523       // Robust search of trace_calling_frame (independant of inlining).
 524       // Assumes saved_regs comes from a pusha in the trace_calling_frame.
 525       assert(cur_frame.sp() < saved_regs, "registers not saved on stack ?");
 526       frame trace_calling_frame = os::get_sender_for_C_frame(&cur_frame);
 527       while (trace_calling_frame.fp() < saved_regs) {
 528         trace_calling_frame = os::get_sender_for_C_frame(&trace_calling_frame);
 529       }
 530 
 531       // safely create a frame and call frame::describe
 532       intptr_t *dump_sp = trace_calling_frame.sender_sp();
 533       intptr_t *dump_fp = trace_calling_frame.link();
 534 
 535       bool walkable = has_mh; // whether the traced frame shoud be walkable
 536 
 537       if (walkable) {
 538         // The previous definition of walkable may have to be refined
 539         // if new call sites cause the next frame constructor to start
 540         // failing. Alternatively, frame constructors could be
 541         // modified to support the current or future non walkable
 542         // frames (but this is more intrusive and is not considered as
 543         // part of this RFE, which will instead use a simpler output).
 544         frame dump_frame = frame(dump_sp, dump_fp);
 545         dump_frame.describe(values, 1);
 546       } else {
 547         // Stack may not be walkable (invalid PC above FP):
 548         // Add descriptions without building a Java frame to avoid issues
 549         values.describe(-1, dump_fp, "fp for #1 <not parsed, cannot trust pc>");
 550         values.describe(-1, dump_sp, "sp for #1");
 551       }
 552       values.describe(-1, entry_sp, "raw top of stack");
 553 
 554       tty->print_cr("Stack layout:");
 555       values.print(p);
 556     }
 557     if (has_mh && mh->is_oop()) {
 558       mh->print();
 559       if (java_lang_invoke_MethodHandle::is_instance(mh)) {
 560         if (java_lang_invoke_MethodHandle::form_offset_in_bytes() != 0)
 561           java_lang_invoke_MethodHandle::form(mh)->print();
 562       }
 563     }
 564   }

 506      // dumping last frame with frame::describe
 507 
 508       JavaThread* p = JavaThread::active();
 509 
 510       ResourceMark rm;
 511       PRESERVE_EXCEPTION_MARK; // may not be needed by safer and unexpensive here
 512       FrameValues values;
 513 
 514       // Note: We want to allow trace_method_handle from any call site.
 515       // While trace_method_handle creates a frame, it may be entered
 516       // without a PC on the stack top (e.g. not just after a call).
 517       // Walking that frame could lead to failures due to that invalid PC.
 518       // => carefully detect that frame when doing the stack walking
 519 
 520       // Current C frame
 521       frame cur_frame = os::current_frame();
 522 
 523       // Robust search of trace_calling_frame (independant of inlining).
 524       // Assumes saved_regs comes from a pusha in the trace_calling_frame.
 525       assert(cur_frame.sp() < saved_regs, "registers not saved on stack ?");
 526       frame trace_calling_frame = os::get_sender_for_C_frame(p, &cur_frame);
 527       while (trace_calling_frame.fp() < saved_regs) {
 528         trace_calling_frame = os::get_sender_for_C_frame(p, &trace_calling_frame);
 529       }
 530 
 531       // safely create a frame and call frame::describe
 532       intptr_t *dump_sp = trace_calling_frame.sender_sp();
 533       intptr_t *dump_fp = trace_calling_frame.link();
 534 
 535       bool walkable = has_mh; // whether the traced frame shoud be walkable
 536 
 537       if (walkable) {
 538         // The previous definition of walkable may have to be refined
 539         // if new call sites cause the next frame constructor to start
 540         // failing. Alternatively, frame constructors could be
 541         // modified to support the current or future non walkable
 542         // frames (but this is more intrusive and is not considered as
 543         // part of this RFE, which will instead use a simpler output).
 544         frame dump_frame = frame(p, dump_sp, dump_fp);
 545         dump_frame.describe(values, 1);
 546       } else {
 547         // Stack may not be walkable (invalid PC above FP):
 548         // Add descriptions without building a Java frame to avoid issues
 549         values.describe(-1, dump_fp, "fp for #1 <not parsed, cannot trust pc>");
 550         values.describe(-1, dump_sp, "sp for #1");
 551       }
 552       values.describe(-1, entry_sp, "raw top of stack");
 553 
 554       tty->print_cr("Stack layout:");
 555       values.print(p);
 556     }
 557     if (has_mh && mh->is_oop()) {
 558       mh->print();
 559       if (java_lang_invoke_MethodHandle::is_instance(mh)) {
 560         if (java_lang_invoke_MethodHandle::form_offset_in_bytes() != 0)
 561           java_lang_invoke_MethodHandle::form(mh)->print();
 562       }
 563     }
 564   }