Uses an object pool on x64

runtime/vm/assembler_x64.h

Index: runtime/vm/assembler_x64.h
===================================================================
--- runtime/vm/assembler_x64.h	(revision 27135)
+++ runtime/vm/assembler_x64.h	(working copy)
@@ -183,6 +183,15 @@
     }
   }
 
+  Address(Register base, int32_t disp, bool fixed) {

[Florian Schneider, 2013/09/05 10:57:45]

Please add a test to assembler_x64_test.cc for this encodings.

[Florian Schneider, 2013/09/05 10:57:45]

Consider making this private and add Assembler as a friend class of Address. I
think this should normally not be used by other classes.

[zra, 2013/09/05 20:29:26]

Done.

[zra, 2013/09/05 20:29:26]

Done.

+    ASSERT(fixed);
+    SetModRM(2, base);
+    if ((base & 7) == RSP) {
+      SetSIB(TIMES_1, RSP, base);
+    }
+    SetDisp32(disp);
+  }
+
   Address(Register index, ScaleFactor scale, int32_t disp) {
     ASSERT(index != RSP);  // Illegal addressing mode.
     SetModRM(0, RSP);
@@ -321,14 +330,8 @@
 
 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 +345,7 @@
   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 +655,21 @@
 
   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);

[Florian Schneider, 2013/09/05 10:57:45]

You really only need 

LoadObject(Register dst, const Object& obj, Register pp);

This way, you also catch all remaining call-sites of LoadObject via compile-time
errors and can inspect them one-by-one. If all sites have PP as pool register,
then you could even remove the pp parameter.

[zra, 2013/09/05 20:29:26]

LoadObject is used in arch generic code. Changing its signature will require
adding an argument at all call-sites across all architectures. I opted to just
use LoadObject everwhere the pool-pointer is PP, and LoadObjectFromPool where
the pool-pointer isn't PP. 

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

Ok. But here is only one arch-independent place in
FlowGraphCompiler::EmitUnoptimizedStaticCall where LoadObject is used. You could
just move this function to the arch-specific files.

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

Done with pool pointer argument added.

+  void LoadObject(Register dst, const Object& object) {
+    LoadObjectFromPool(dst, object, PP);
+  }
+  void JumpPatchable(const ExternalLabel* label, Register pp);
+  void JumpFromPool(const ExternalLabel* label, Register pp);
+  void ConditionalJumpFromPool(Condition condition, const ExternalLabel* label,
+                               Register 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);
@@ -680,6 +697,7 @@
 
   void EnterFrame(intptr_t frame_space);
   void LeaveFrame();
+  void LeaveFrameWithPP();
   void ReserveAlignedFrameSpace(intptr_t frame_space);
 
   // Create a frame for calling into runtime that preserves all volatile
@@ -731,6 +749,8 @@
     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 +759,7 @@
   //   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 +767,15 @@
   //   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, 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 +791,9 @@
   //   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:
@@ -802,7 +826,7 @@
 
  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 {
@@ -822,6 +846,15 @@
 
   GrowableArray<CodeComment*> comments_;
 
+  intptr_t AddObject(const Object& obj);
+  intptr_t AddExternalLabel(const ExternalLabel* label, Patchability patchable);
+  void LoadExternalLabel(Register dst,
+                         const ExternalLabel* label,
+                         Patchability patchabe,

[Florian Schneider, 2013/09/05 10:57:45]

s/patchabe/patchable/

[zra, 2013/09/05 20:29:26]

Done.

+                         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);