Uses an object pool on x64

runtime/vm/assembler_x64.h

Index: runtime/vm/assembler_x64.h
===================================================================
--- runtime/vm/assembler_x64.h	(revision 26726)
+++ runtime/vm/assembler_x64.h	(working copy)
@@ -321,14 +321,8 @@
 
 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 +336,7 @@
   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 +646,32 @@
 
   void Drop(intptr_t stack_elements);
 
-  void LoadObject(Register dst, const Object& object);
+  enum Patchability {
+    kPatchable,
+    kNotPatchable,
+  };
+
+  int32_t AddObject(const Object& obj);
+  int32_t AddExternalLabel(const ExternalLabel* label,
+                           Patchability patchable = kPatchable);
+  bool CanLoadFromObjectPool(const Object& object);

[Florian Schneider, 2013/09/04 09:39:47]

I don't see this function used anywhere outside the Assembler class: I'd make it
private.

[zra, 2013/09/04 21:00:41]

Done.

+  void LoadWordFromPoolOffset(Register dst, Register pp, int32_t offset,

[Florian Schneider, 2013/09/04 09:39:47]

I don't see this function used anywhere outside the Assembler class: I'd make it
private.

[zra, 2013/09/04 21:00:41]

Done.

+                              Patchability patchable);
+  void LoadExternalLabel(const ExternalLabel* label,

[Florian Schneider, 2013/09/04 09:39:47]

I don't see this function used anywhere outside the Assembler class: I'd make it
private and remove the optional arguments.

[zra, 2013/09/04 21:00:41]

Done.

+                         Patchability = kPatchable,

[Florian Schneider, 2013/09/04 09:39:47]

Max one optional argument, and only if absolutely necessary.

[zra, 2013/09/04 21:00:41]

Done.

+                         Register pp = PP);
+
+  // Load object into register dst. The default patchability is kPatchable
+  // because LoadObject is used for a load of ic-data in arch independent code
+  // that must be patchable.
+  void LoadObject(Register dst, const Object& object,
+                  Patchability patchable = kPatchable, Register pp = PP);

[Florian Schneider, 2013/09/04 09:39:47]

Max one optional argument, and only if absolutely necessary.

[zra, 2013/09/04 21:00:41]

Done.

+  void JumpPatchable(const ExternalLabel* label, Register pp = PP);
+  void JumpFromPool(const ExternalLabel* label, Register pp = PP);
+  void JumpFromPool(Condition condition, const ExternalLabel* label,
+                    Register pp = PP);
+  void CallPatchable(const ExternalLabel* label);
+  void CallFromPool(const ExternalLabel* label);
   void StoreObject(const Address& dst, const Object& obj);
   void PushObject(const Object& object);
   void CompareObject(Register reg, const Object& object);
@@ -679,7 +698,7 @@
   }
 
   void EnterFrame(intptr_t frame_space);
-  void LeaveFrame();
+  void LeaveFrame(bool restore_pp = false);

[Florian Schneider, 2013/09/04 09:39:47]

This optional argument seems dangerous, too. Try to avoid it.

[zra, 2013/09/04 21:00:41]

Done.

   void ReserveAlignedFrameSpace(intptr_t frame_space);
 
   // Create a frame for calling into runtime that preserves all volatile
@@ -731,6 +750,8 @@
     buffer_.FinalizeInstructions(region);
   }
 
+  void LoadPoolPointer(Register pp = 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 +760,7 @@
   //   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 +768,17 @@
   //   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 EnterDartFrame(intptr_t frame_size,
+                      Register new_pp = PP, Register new_pc = kNoRegister);

[Florian Schneider, 2013/09/04 09:39:47]

Again, two optional arguments is not a good idea, especially if there are the
same type!

[zra, 2013/09/04 21:00:41]

Done.

 
   // 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 = PP, Register new_pc = kNoRegister);

[Florian Schneider, 2013/09/04 09:39:47]

Again, two optional arguments is not a good idea, especially if there are the
same type!

[zra, 2013/09/04 21:00:41]

Done.

 
   // Set up a stub frame so that the stack traversal code can easily identify
   // a stub frame.
@@ -767,9 +793,9 @@
   //   movq rbp, rsp
   //   pushq immediate(0)
   //   .....
-  void EnterStubFrame();
+  void EnterStubFrame(bool save_pp = false);

[Florian Schneider, 2013/09/04 09:39:47]

This optional argument seems dangerous, too. Try to avoid it.

[zra, 2013/09/04 21:00:41]

Done.

 
-  // 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:
@@ -802,7 +828,7 @@
 
  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 {