VM: Emit compacter code for x64 branches to external labels.

runtime/vm/instructions_x64.cc

 // Copyright (c) 2012, 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"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/cpu.h"
 #include "vm/instructions.h"
 #include "vm/object.h"
@@ skipping 19 matching lines @@
   for (int i = 0; i < num_bytes; i++) {
     // Skip comparison for data[i] < 0.
     if ((data[i] >= 0) && (byte_array[i] != (0xFF & data[i]))) {
       return false;
     }
   }
   return true;
 }
 
 
-uword CallPattern::TargetAddress() const {
-  ASSERT(IsValid());
-  return *reinterpret_cast<uword*>(start() + 2);
-}
-
-
-void CallPattern::SetTargetAddress(uword target) const {
-  ASSERT(IsValid());
-  *reinterpret_cast<uword*>(start() + 2) = target;
-  CPU::FlushICache(start() + 2, kWordSize);
-}
-
-
-const int* CallPattern::pattern() const {
-  // movq $target, TMP
-  // callq *TMP
-  static const int kCallPattern[kLengthInBytes] =
-      {0x49, 0xBB, -1, -1, -1, -1, -1, -1, -1, -1, 0x41, 0xFF, 0xD3};
-  return kCallPattern;
-}
-
-
 uword JumpPattern::TargetAddress() const {
   ASSERT(IsValid());
   int index = InstructionPattern::IndexFromPPLoad(start() + 3);
   return reinterpret_cast<uword>(object_pool_.At(index));
 }
 
 
 void JumpPattern::SetTargetAddress(uword target) const {
   ASSERT(IsValid());
   int index = InstructionPattern::IndexFromPPLoad(start() + 3);
   const Smi& smi = Smi::Handle(reinterpret_cast<RawSmi*>(target));
   object_pool_.SetAt(index, smi);
   // No need to flush the instruction cache, since the code is not modified.
 }
 
 
 const int* JumpPattern::pattern() const {
-  //  00: 4d 8b 9d imm32  mov R11, [R13 + off]
-  //  07: 41 ff e3        jmpq R11
+  //  07: 41 ff a7 imm32  jmpq [reg + off]
   static const int kJumpPattern[kLengthInBytes] =
-      {0x4D, 0x8B, -1, -1, -1, -1, -1, 0x41, 0xFF, 0xE3};
+      {0x41, 0xFF, -1, -1, -1, -1, -1};
   return kJumpPattern;
 }
 
 
 void ShortCallPattern::SetTargetAddress(uword target) const {
   ASSERT(IsValid());
   *reinterpret_cast<uint32_t*>(start() + 1) = target - start() - kLengthInBytes;
   CPU::FlushICache(start() + 1, kWordSize);
 }
 
 
 const int* ShortCallPattern::pattern() const {
   static const int kCallPattern[kLengthInBytes] = {0xE8, -1, -1, -1, -1};
   return kCallPattern;
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64