VM: Store edge counters in one per-function array.

runtime/vm/code_patcher_arm64.cc

 // Copyright (c) 2014, 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_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/code_patcher.h"
 #include "vm/cpu.h"
 #include "vm/instructions.h"
@@ skipping 120 matching lines @@
 
 uword CodePatcher::GetNativeCallAt(uword return_address,
                                    const Code& code,
                                    NativeFunction* target) {
   ASSERT(code.ContainsInstructionAt(return_address));
   NativeCallPattern call(return_address, code);
   *target = call.native_function();
   return call.target();
 }
 
-
-// This class pattern matches on a load from the object pool.  Loading on
-// ARM64 is complicated because it can take more than one form.  We
-// match backwards from the end of the sequence so we can reuse the code for
-// matching object pool loads at calls.
-class EdgeCounter : public ValueObject {
- public:
-  EdgeCounter(uword pc, const Code& code)
-      : end_(pc - kAdjust),
-        object_pool_(ObjectPool::Handle(code.GetObjectPool())) {
-    // An IsValid predicate is complicated and duplicates the code in the
-    // decoding function.  Instead we rely on decoding the pattern which
-    // will assert partial validity.
-  }
-
-  RawObject* edge_counter() const {
-    Register ignored;
-    intptr_t index;
-    InstructionPattern::DecodeLoadWordFromPool(end_, &ignored, &index);
-    ASSERT(ignored == R0);
-    return object_pool_.ObjectAt(index);
-  }
-
- private:
-  // The object pool load is followed by the fixed-size edge counter
-  // incrementing code:
-  //     ldr ip, [r0, #+11]
-  //     adds ip, ip, #2
-  //     str ip, [r0, #+11]
-  static const intptr_t kAdjust = 3 * Instr::kInstrSize;
-
-  uword end_;
-  const ObjectPool& object_pool_;
-};
-
-
-RawObject* CodePatcher::GetEdgeCounterAt(uword pc, const Code& code) {
-  ASSERT(code.ContainsInstructionAt(pc));
-  EdgeCounter counter(pc, code);
-  return counter.edge_counter();
-}
-
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64