WIP

Author: offamitkumar

src/hotspot/cpu/s390/interp_masm_s390.cpp

@@ -24,7 +24,7 @@
  */
 
 // Major contributions by AHa, AS, JL, ML.
-
+long fubar = 0;
 #include "asm/macroAssembler.inline.hpp"
 #include "gc/shared/barrierSet.hpp"
 #include "gc/shared/barrierSetAssembler.hpp"
@@ -182,10 +182,35 @@ void InterpreterMacroAssembler::call_VM_preemptable(Register oop_result, address
   }
 #endif // ASSERT
 
+  Label resume_pc, not_preempted;
+  push_cont_fastpath();
+
+  assert(arg_1 != Z_ARG1, "register corruption");
+  load_const_optimized(Z_R1, (uintptr_t)&fubar);
+  z_agsi(0, Z_R1, 1);
+  z_lg(Z_ARG1, Address(Z_SP, _z_abi(callers_sp)));
+
+  // We set resume_pc as last java pc. It will be saved if the vthread gets preempted.
+  // Later execution will continue right there.
+  lr_if_needed(Z_ARG2, arg_1);
+
+  call_VM(oop_result, entry_point, false /*check_exceptions*/, &resume_pc /* last_java_pc */);
+
+  pop_cont_fastpath();
+
+  // Jump to handler if the call was preempted
+  z_lg(Z_R1_scratch, Address(Z_thread, in_bytes(JavaThread::preempt_alternate_return_offset())));
+  z_ltgr(Z_R1_scratch, Z_R1_scratch);
+  z_brz(not_preempted);
+
+  z_mvghi(Address(Z_thread, in_bytes(JavaThread::preempt_alternate_return_offset())), 0);
+  z_br(Z_R1_scratch);  // branch to handler in Z_R1_scratch 
 
+  bind(resume_pc); // Location to resume execution
 
+  stop("restore_after_resume");
 
-  stop("not yet implemented call_VM_preemptable");
+  bind(not_preempted);
 }
 
 void InterpreterMacroAssembler::call_VM_leaf_base(address entry_point) {

src/hotspot/cpu/s390/macroAssembler_s390.cpp

@@ -1937,6 +1937,12 @@ unsigned long MacroAssembler::patched_branch(address dest_pos, unsigned long ins
 // Only called when binding labels (share/vm/asm/assembler.cpp)
 // Pass arguments as intended. Do not pre-calculate distance.
 void MacroAssembler::pd_patch_instruction(address branch, address target, const char* file, int line) {
+
+  if (is_load_const(branch)) {
+    patch_const(branch, (long)target);
+    return;
+  }
+
   unsigned long stub_inst;
   int           inst_len = get_instruction(branch, &stub_inst);
 
@@ -3861,7 +3867,7 @@ void MacroAssembler::set_top_ijava_frame_at_SP_as_last_Java_frame(Register sp, R
       load_const_optimized(tmp1, target(*jpc));
     }
   } else {
-    load_const_optimized(tmp1, *jpc);
+    load_const(tmp1, *jpc);
   }
   set_last_Java_frame(/*sp=*/sp, /*pc=*/tmp1, allow_relocation);
 }