Reapply "Initial implementation of on-stack replacement (OSR)."

runtime/vm/assembler_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/heap.h"
 #include "vm/memory_region.h"
 #include "vm/runtime_entry.h"
+#include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, print_stop_message, true, "Print stop message.");
 DEFINE_FLAG(bool, use_sse41, true, "Use SSE 4.1 if available");
 DECLARE_FLAG(bool, inline_alloc);
 
 
 bool CPUFeatures::sse4_1_supported_ = false;
@@ skipping 2250 matching lines @@
   leave();
 }
 
 
 void Assembler::CallRuntime(const RuntimeEntry& entry) {
   entry.Call(this);
 }
 
 
 void Assembler::EnterDartFrame(intptr_t frame_size) {
-  const intptr_t offset = CodeSize();
   EnterFrame(0);
   Label dart_entry;
   call(&dart_entry);
   Bind(&dart_entry);
-  // Adjust saved PC for any intrinsic code that could have been generated
-  // before a frame is created.
+  // The runtime system assumes that the code marker address is
+  // kEntryPointToPcMarkerOffset bytes from the entry.  If there is any code
+  // generated before entering the frame, the address needs to be adjusted.
+  const intptr_t offset = kEntryPointToPcMarkerOffset - CodeSize();
   if (offset != 0) {
-    addq(Address(RSP, 0), Immediate(-offset));
+    addq(Address(RSP, 0), Immediate(offset));
   }
   if (frame_size != 0) {
     subq(RSP, Immediate(frame_size));
   }
 }
 
 
+// On entry to a function compiled for OSR, the caller's frame pointer, the
+// stack locals, and any copied parameters are already in place.  The frame
+// pointer is already set up.  The PC marker is not correct for the
+// optimized function and there may be extra space for spill slots to
+// allocate.
+void Assembler::EnterOsrFrame(intptr_t extra_size) {
+  Label dart_entry;
+  call(&dart_entry);
+  Bind(&dart_entry);
+  // The runtime system assumes that the code marker address is
+  // kEntryPointToPcMarkerOffset bytes from the entry.  Since there is no
+  // code to set up the frame pointer, the address needs to be adjusted.
+  const intptr_t offset = kEntryPointToPcMarkerOffset - CodeSize();
+  if (offset != 0) {
+    addq(Address(RSP, 0), Immediate(offset));
+  }
+  popq(Address(RBP, kPcMarkerSlotFromFp * kWordSize));
+  if (extra_size != 0) {
+    subq(RSP, Immediate(extra_size));
+  }
+}
+
+
 void Assembler::EnterStubFrame() {
   EnterFrame(0);
   pushq(Immediate(0));  // Push 0 in the saved PC area for stub frames.
 }
 
 
 void Assembler::TryAllocate(const Class& cls,
                             Label* failure,
                             bool near_jump,
                             Register instance_reg) {
@@ skipping 212 matching lines @@
 
 const char* Assembler::FpuRegisterName(FpuRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfXmmRegisters));
   return xmm_reg_names[reg];
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64