Revert "VM: New calling convention for generated code."

runtime/vm/assembler_x64.h

Index: runtime/vm/assembler_x64.h
diff --git a/runtime/vm/assembler_x64.h b/runtime/vm/assembler_x64.h
index 6650fd94a7ac57749f942e9dfc534e4b629684f6..a6d64db0dc3f2c5be230533751d6b06868353567 100644
--- a/runtime/vm/assembler_x64.h
+++ b/runtime/vm/assembler_x64.h
@@ -366,7 +366,7 @@ class Assembler : public ValueObject {
   void call(Label* label);
   void call(const ExternalLabel* label);
 
-  static const intptr_t kCallExternalLabelSize = 15;
+  static const intptr_t kCallExternalLabelSize = 7;
 
   void pushq(Register reg);
   void pushq(const Address& address);
@@ -770,7 +770,7 @@ class Assembler : public ValueObject {
                                   const Function& function,
                                   Register new_pp);
   void JmpPatchable(const StubEntry& stub_entry, Register pp);
-  void Jmp(const StubEntry& stub_entry, Register pp = PP);
+  void Jmp(const StubEntry& stub_entry, Register pp);
   void J(Condition condition, const StubEntry& stub_entry, Register pp);
   void CallPatchable(const StubEntry& stub_entry);
   void Call(const StubEntry& stub_entry);
@@ -832,8 +832,6 @@ class Assembler : public ValueObject {
   void PushRegisters(intptr_t cpu_register_set, intptr_t xmm_register_set);
   void PopRegisters(intptr_t cpu_register_set, intptr_t xmm_register_set);
 
-  void CheckCodePointer();
-
   void EnterFrame(intptr_t frame_space);
   void LeaveFrame();
   void ReserveAlignedFrameSpace(intptr_t frame_space);
@@ -924,7 +922,6 @@ class Assembler : public ValueObject {
     buffer_.FinalizeInstructions(region);
   }
 
-  void RestoreCodePointer();
   void LoadPoolPointer(Register pp = PP);
 
   // Set up a Dart frame on entry with a frame pointer and PC information to
@@ -946,13 +943,16 @@ class Assembler : public ValueObject {
   //   ...
   //   pushq r15
   //   .....
-  void EnterDartFrame(intptr_t frame_size, Register new_pp);
-  void LeaveDartFrame(RestorePP restore_pp = kRestoreCallerPP);
+  void EnterDartFrame(intptr_t frame_size,
+                      Register new_pp,
+                      Register pc_marker_override);
+  void LeaveDartFrame();
 
   // Set up a Dart frame for a function compiled for on-stack replacement.
   // The frame layout is a normal Dart frame, but the frame is partially set
   // up on entry (it is the frame of the unoptimized code).
-  void EnterOsrFrame(intptr_t extra_size);
+  void EnterOsrFrame(intptr_t extra_size,
+                     Register new_pp, Register pc_marker_override);
 
   // Set up a stub frame so that the stack traversal code can easily identify
   // a stub frame.
@@ -970,6 +970,19 @@ class Assembler : public ValueObject {
   void EnterStubFrame();
   void LeaveStubFrame();
 
+  // Instruction pattern from entrypoint is used in dart frame prologues
+  // to set up the frame and save a PC which can be used to figure out the
+  // RawInstruction object corresponding to the code running in the frame.
+  // entrypoint:
+  //   pushq rbp          (size is 1 byte)
+  //   movq rbp, rsp      (size is 3 bytes)
+  //   call L             (size is 5 bytes)
+  //   L:
+  static const intptr_t kEntryPointToPcMarkerOffset = 0;
+  static intptr_t EntryPointToPcMarkerOffset() {
+    return kEntryPointToPcMarkerOffset;
+  }
+
   void UpdateAllocationStats(intptr_t cid,
                              Heap::Space space,
                              bool inline_isolate = true);