Pattern match on generated code to find edge counters.

runtime/vm/instructions_arm.h

Index: runtime/vm/instructions_arm.h
diff --git a/runtime/vm/instructions_arm.h b/runtime/vm/instructions_arm.h
index 59cb2595866f54c7315c43573007e07eb674684a..7ae39451ac094c66016c91fe2f9758f8278206da 100644
--- a/runtime/vm/instructions_arm.h
+++ b/runtime/vm/instructions_arm.h
@@ -15,6 +15,38 @@
 
 namespace dart {
 
+class InstructionPattern : public AllStatic {
+ public:
+  // Decodes a load sequence ending at 'end' (the last instruction of the load
+  // sequence is the instruction before the one at end).  Returns a pointer to
+  // the first instruction in the sequence.  Returns the register being loaded
+  // and the loaded object in the output parameters 'reg' and 'obj'
+  // respectively.
+  static const uword* DecodeLoadObject(const uword* end,
+                                       const Array& object_pool,
+                                       Register* reg,
+                                       Object* obj);
+
+  // Decodes a load sequence ending at 'end' (the last instruction of the load
+  // sequence is the instruction before the one at end).  Returns a pointer to
+  // the first instruction in the sequence.  Returns the register being loaded
+  // and the loaded immediate value in the output parameters 'reg' and 'value'
+  // respectively.
+  static const uword* DecodeLoadWordImmediate(const uword* end,
+                                              Register* reg,
+                                              intptr_t* value);
+
+  // Decodes a load sequence ending at 'end' (the last instruction of the load
+  // sequence is the instruction before the one at end).  Returns a pointer to
+  // the first instruction in the sequence.  Returns the register being loaded
+  // and the index in the pool being read from in the output parameters 'reg'
+  // and 'index' respectively.
+  static const uword* DecodeLoadWordFromPool(const uword* end,
+                                             Register* reg,
+                                             intptr_t* index);
+};
+
+
 class CallPattern : public ValueObject {
  public:
   CallPattern(uword pc, const Code& code);
@@ -32,17 +64,15 @@ class CallPattern : public ValueObject {
   static void InsertAt(uword pc, uword target_address);
 
  private:
-  uword Back(int n) const;
-  int DecodeLoadObject(int end, Register* reg, Object* obj);
-  int DecodeLoadWordImmediate(int end, Register* reg, int* value);
-  int DecodeLoadWordFromPool(int end, Register* reg, int* index);
+  const Array& object_pool_;
+
   const uword* end_;
-  int target_address_pool_index_;
-  int args_desc_load_end_;
+  const uword* args_desc_load_end_;
+  const uword* ic_data_load_end_;
+
+  intptr_t target_address_pool_index_;
   Array& args_desc_;
-  int ic_data_load_end_;
   ICData& ic_data_;
-  const Array& object_pool_;
 
   DISALLOW_COPY_AND_ASSIGN(CallPattern);
 };
@@ -71,4 +101,3 @@ class JumpPattern : public ValueObject {
 }  // namespace dart
 
 #endif  // VM_INSTRUCTIONS_ARM_H_
-