Uses an object pool on x64

runtime/vm/assembler_x64.h

Index: runtime/vm/assembler_x64.h
===================================================================
--- runtime/vm/assembler_x64.h	(revision 27208)
+++ runtime/vm/assembler_x64.h	(working copy)
@@ -212,6 +212,18 @@
     Operand::operator=(other);
     return *this;
   }
+
+ private:
+  Address(Register base, int32_t disp, bool fixed) {
+    ASSERT(fixed);
+    SetModRM(2, base);
+    if ((base & 7) == RSP) {
+      SetSIB(TIMES_1, RSP, base);
+    }
+    SetDisp32(disp);
+  }
+
+  friend class Assembler;
 };
 
 
@@ -321,14 +333,8 @@
 
 class Assembler : public ValueObject {
  public:
-  explicit Assembler(bool use_far_branches = false)
-      : buffer_(),
-        object_pool_(GrowableObjectArray::Handle()),
-        prologue_offset_(-1),
-        comments_() {
-    // This mode is only needed and implemented for MIPS and ARM.
-    ASSERT(!use_far_branches);
-  }
+  explicit Assembler(bool use_far_branches = false);
+
   ~Assembler() { }
 
   static const bool kNearJump = true;
@@ -342,7 +348,7 @@
   void call(Label* label);
   void call(const ExternalLabel* label);
 
-  static const intptr_t kCallExternalLabelSize = 13;
+  static const intptr_t kCallExternalLabelSize = 10;
 
   void pushq(Register reg);
   void pushq(const Address& address);
@@ -652,7 +658,20 @@
 
   void Drop(intptr_t stack_elements);
 
-  void LoadObject(Register dst, const Object& object);
+  enum Patchability {
+    kPatchable,
+    kNotPatchable,
+  };
+
+  void LoadObjectFromPool(Register dst, const Object& obj, Register pp);
+  void LoadObject(Register dst, const Object& object) {
+    LoadObjectFromPool(dst, object, PP);
+  }
+  void JmpPatchable(const ExternalLabel* label, Register pp);
+  void Jmp(const ExternalLabel* label, Register pp);
+  void J(Condition condition, const ExternalLabel* label, Register pp);
+  void CallPatchable(const ExternalLabel* label);
+  void Call(const ExternalLabel* label, Register pp);
   void StoreObject(const Address& dst, const Object& obj);
   void PushObject(const Object& object);
   void CompareObject(Register reg, const Object& object);
@@ -680,6 +699,8 @@
 
   void EnterFrame(intptr_t frame_space);
   void LeaveFrame();
+  void LeaveFrameWithPP();
+  void ReturnPatchable();
   void ReserveAlignedFrameSpace(intptr_t frame_space);
 
   // Create a frame for calling into runtime that preserves all volatile
@@ -731,6 +752,8 @@
     buffer_.FinalizeInstructions(region);
   }
 
+  void LoadPoolPointer(Register pp);
+
   // Set up a Dart frame on entry with a frame pointer and PC information to
   // enable easy access to the RawInstruction object of code corresponding
   // to this frame.
@@ -739,6 +762,7 @@
   //   ret PC
   //   saved RBP     <=== RBP
   //   pc (used to derive the RawInstruction Object of the dart code)
+  //   saved PP
   //   locals space  <=== RSP
   //   .....
   // This code sets this up with the sequence:
@@ -746,13 +770,17 @@
   //   movq rbp, rsp
   //   call L
   //   L: <code to adjust saved pc if there is any intrinsification code>
+  //   ...
+  //   pushq r15
   //   .....
   void EnterDartFrame(intptr_t frame_size);
+  void EnterDartFrameWithInfo(intptr_t frame_size,
+                              Register new_pp, Register new_pc);
 
   // 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 new_pc);
 
   // Set up a stub frame so that the stack traversal code can easily identify
   // a stub frame.
@@ -768,8 +796,9 @@
   //   pushq immediate(0)
   //   .....
   void EnterStubFrame();
+  void EnterStubFrameWithPP();
 
-  // Instruction pattern from entrypoint is used in dart frame prologs
+  // 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:
@@ -800,9 +829,11 @@
 
   static const char* FpuRegisterName(FpuRegister reg);
 
+  void FixedSizeAddressOffsetTest();

[Florian Schneider, 2013/09/06 09:58:15]

I see - Let me suggest to add a static factory method to Address:

static Address AddressBaseImm32(Register base, int32_t disp);

This way you can add the test function to the _test file - and the name states
better what it generates than the overloaded constructor with an extra bool
argument.

[zra, 2013/09/06 17:53:26]

Done.

+
  private:
   AssemblerBuffer buffer_;
-  GrowableObjectArray& object_pool_;  // Object pool is not used on x64.
+  GrowableObjectArray& object_pool_;  // Objects and patchable jump targets.
   int prologue_offset_;
 
   class CodeComment : public ZoneAllocated {
@@ -822,6 +853,16 @@
 
   GrowableArray<CodeComment*> comments_;
 
+  intptr_t FindObject(const Object& obj);
+  intptr_t FindExternalLabel(const ExternalLabel* label,
+                             Patchability patchable);
+  void LoadExternalLabel(Register dst,
+                         const ExternalLabel* label,
+                         Patchability patchable,
+                         Register pp);
+  bool CanLoadFromObjectPool(const Object& object);
+  void LoadWordFromPoolOffset(Register dst, Register pp, int32_t offset);
+
   inline void EmitUint8(uint8_t value);
   inline void EmitInt32(int32_t value);
   inline void EmitInt64(int64_t value);