Remove loading of function object in static calls.

runtime/vm/code_patcher_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/assembler.h"
 #include "vm/code_patcher.h"
 #include "vm/cpu.h"
 #include "vm/instructions.h"
 #include "vm/object.h"
 #include "vm/raw_object.h"
 
 namespace dart {
 
-// The pattern of a Dart call is:
+// The pattern of a Dart instance call is:
 //  00: 48 bb imm64  mov RBX, immediate 1
 //  10: 49 ba imm64  mov R10, immediate 2
 //  20: 49 bb imm64  mov R11, target_address
 //  30: 41 ff d3     call R11
 //  33: <- return_address
 class DartCallPattern : public ValueObject {
  public:
   explicit DartCallPattern(uword return_address)
       : start_(return_address - kCallPatternSize) {
     ASSERT(IsValid(return_address));
@@ skipping 52 matching lines @@
     Smi& num_pos_args = Smi::Handle();
     num_pos_args ^= args_desc.At(1);
     return num_args.Value() - num_pos_args.Value();
   }
 
   uword start_;
   DISALLOW_IMPLICIT_CONSTRUCTORS(DartCallPattern);
 };
 
 
-// A Dart static call passes the function object in RBX.
-class StaticCall : public DartCallPattern {
- public:
-  explicit StaticCall(uword return_address)
-      : DartCallPattern(return_address) {}
-
-  RawFunction* function() const {
-    Function& f = Function::Handle();
-    f ^= reinterpret_cast<RawObject*>(immediate_one());
-    return f.raw();
-  }
-
- private:
-  DISALLOW_IMPLICIT_CONSTRUCTORS(StaticCall);
-};
-
-
 // A Dart instance call passes the ic-data in RBX.
+// The expected pattern of a dart instance call:
+//  mov RBX, ic-data
+//  mov R10, argument_descriptor_array
+//  mov R11, target_address
+//  call R11
+//  <- return address
 class InstanceCall : public DartCallPattern {
  public:
   explicit InstanceCall(uword return_address)
       : DartCallPattern(return_address) {}
 
   RawICData* ic_data() const {
     ICData& ic_data = ICData::Handle();
     ic_data ^= reinterpret_cast<RawObject*>(immediate_one());
     return ic_data.raw();
   }
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(InstanceCall);
 };
 
 
+// The expected pattern of a dart static call:
+//  mov R10, argument_descriptor_array (10 bytes)
+//  mov R11, target_address (10 bytes)
+//  call R11  (3 bytes)
+//  <- return address
+class StaticCall : public ValueObject {
+ public:
+  explicit StaticCall(uword return_address)
+      : start_(return_address - kCallPatternSize) {
+    ASSERT(IsValid(return_address));
+    ASSERT((kCallPatternSize - 10) == Assembler::kCallExternalLabelSize);
+  }
+
+  static const int kCallPatternSize = 23;
+
+  static bool IsValid(uword return_address) {
+    uint8_t* code_bytes =
+        reinterpret_cast<uint8_t*>(return_address - kCallPatternSize);
+    return (code_bytes[00] == 0x49) && (code_bytes[01] == 0xBA) &&
+           (code_bytes[10] == 0x49) && (code_bytes[11] == 0xBB) &&
+           (code_bytes[20] == 0x41) && (code_bytes[21] == 0xFF) &&
+           (code_bytes[22] == 0xD3);
+  }
+
+  uword target() const {
+    return *reinterpret_cast<uword*>(start_ + 10 + 2);
+  }
+
+  void set_target(uword target) const {
+    uword* target_addr = reinterpret_cast<uword*>(start_ + 10 + 2);
+    *target_addr = target;
+    CPU::FlushICache(start_ + 10, 2 + 8);
+  }
+
+ private:
+  uword start_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(StaticCall);
+};
+
+
 uword CodePatcher::GetStaticCallTargetAt(uword return_address) {
   StaticCall call(return_address);
   return call.target();
 }
 
 
 void CodePatcher::PatchStaticCallAt(uword return_address, uword new_target) {
   StaticCall call(return_address);
   call.set_target(new_target);
 }
@@ skipping 107 matching lines @@
   *reinterpret_cast<uint8_t*>(start) = 0xE8;
   ShortCallPattern call(start);
   call.SetTargetAddress(target);
   CPU::FlushICache(start, ShortCallPattern::InstructionLength());
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64