Revert "Revert "Optimize IMT""

This reverts commit 88f288e3564d79d87c0cd8bb831ec5a791ba4861.

Change-Id: I49605d53692cbec1e2622e23ff2893fc51ed4115
diff --git a/runtime/mirror/class.h b/runtime/mirror/class.h
index 5235a3e..f044b59 100644
--- a/runtime/mirror/class.h
+++ b/runtime/mirror/class.h
@@ -22,6 +22,7 @@
 #include "class_flags.h"
 #include "gc_root.h"
 #include "gc/allocator_type.h"
+#include "imtable.h"
 #include "invoke_type.h"
 #include "modifiers.h"
 #include "object.h"
@@ -33,10 +34,6 @@
 #include "thread.h"
 #include "utils.h"
 
-#ifndef IMT_SIZE
-#error IMT_SIZE not defined
-#endif
-
 namespace art {
 
 class ArtField;
@@ -66,11 +63,6 @@
   // 2 ref instance fields.]
   static constexpr uint32_t kClassWalkSuper = 0xC0000000;
 
-  // Interface method table size. Increasing this value reduces the chance of two interface methods
-  // colliding in the interface method table but increases the size of classes that implement
-  // (non-marker) interfaces.
-  static constexpr size_t kImtSize = IMT_SIZE;
-
   // Class Status
   //
   // kStatusRetired: Class that's temporarily used till class linking time
@@ -351,7 +343,7 @@
   // be replaced with a class with the right size for embedded imt/vtable.
   bool IsTemp() SHARED_REQUIRES(Locks::mutator_lock_) {
     Status s = GetStatus();
-    return s < Status::kStatusResolving && ShouldHaveEmbeddedImtAndVTable();
+    return s < Status::kStatusResolving && ShouldHaveEmbeddedVTable();
   }
 
   String* GetName() SHARED_REQUIRES(Locks::mutator_lock_);  // Returns the cached name.
@@ -557,7 +549,7 @@
       SHARED_REQUIRES(Locks::mutator_lock_);
 
   // Compute how many bytes would be used a class with the given elements.
-  static uint32_t ComputeClassSize(bool has_embedded_tables,
+  static uint32_t ComputeClassSize(bool has_embedded_vtable,
                                    uint32_t num_vtable_entries,
                                    uint32_t num_8bit_static_fields,
                                    uint32_t num_16bit_static_fields,
@@ -830,28 +822,27 @@
     return MemberOffset(sizeof(Class));
   }
 
+  static MemberOffset ImtPtrOffset(size_t pointer_size) {
+    return MemberOffset(
+        RoundUp(EmbeddedVTableLengthOffset().Uint32Value() + sizeof(uint32_t), pointer_size));
+  }
+
   template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags,
            ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
-  bool ShouldHaveEmbeddedImtAndVTable() SHARED_REQUIRES(Locks::mutator_lock_) {
+  bool ShouldHaveImt() SHARED_REQUIRES(Locks::mutator_lock_) {
+    return ShouldHaveEmbeddedVTable<kVerifyFlags, kReadBarrierOption>();
+  }
+
+  template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags,
+           ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
+  bool ShouldHaveEmbeddedVTable() SHARED_REQUIRES(Locks::mutator_lock_) {
     return IsInstantiable<kVerifyFlags, kReadBarrierOption>();
   }
 
   bool HasVTable() SHARED_REQUIRES(Locks::mutator_lock_);
 
-  static MemberOffset EmbeddedImTableEntryOffset(uint32_t i, size_t pointer_size);
-
   static MemberOffset EmbeddedVTableEntryOffset(uint32_t i, size_t pointer_size);
 
-  template <VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags,
-            ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
-  ArtMethod* GetEmbeddedImTableEntry(uint32_t i, size_t pointer_size)
-      SHARED_REQUIRES(Locks::mutator_lock_);
-
-  template <VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags,
-            ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
-  void SetEmbeddedImTableEntry(uint32_t i, ArtMethod* method, size_t pointer_size)
-      SHARED_REQUIRES(Locks::mutator_lock_);
-
   int32_t GetVTableLength() SHARED_REQUIRES(Locks::mutator_lock_);
 
   ArtMethod* GetVTableEntry(uint32_t i, size_t pointer_size)
@@ -861,6 +852,10 @@
 
   void SetEmbeddedVTableLength(int32_t len) SHARED_REQUIRES(Locks::mutator_lock_);
 
+  ImTable* GetImt(size_t pointer_size) SHARED_REQUIRES(Locks::mutator_lock_);
+
+  void SetImt(ImTable* imt, size_t pointer_size) SHARED_REQUIRES(Locks::mutator_lock_);
+
   ArtMethod* GetEmbeddedVTableEntry(uint32_t i, size_t pointer_size)
       SHARED_REQUIRES(Locks::mutator_lock_);
 
@@ -870,7 +865,7 @@
   inline void SetEmbeddedVTableEntryUnchecked(uint32_t i, ArtMethod* method, size_t pointer_size)
       SHARED_REQUIRES(Locks::mutator_lock_);
 
-  void PopulateEmbeddedImtAndVTable(ArtMethod* const (&methods)[kImtSize], size_t pointer_size)
+  void PopulateEmbeddedVTable(size_t pointer_size)
       SHARED_REQUIRES(Locks::mutator_lock_);
 
   // Given a method implemented by this class but potentially from a super class, return the
@@ -1195,7 +1190,7 @@
   void AssertInitializedOrInitializingInThread(Thread* self)
       SHARED_REQUIRES(Locks::mutator_lock_);
 
-  Class* CopyOf(Thread* self, int32_t new_length, ArtMethod* const (&imt)[mirror::Class::kImtSize],
+  Class* CopyOf(Thread* self, int32_t new_length, ImTable* imt,
                 size_t pointer_size)
       SHARED_REQUIRES(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
 
@@ -1322,10 +1317,7 @@
 
   // Check that the pointer size matches the one in the class linker.
   ALWAYS_INLINE static void CheckPointerSize(size_t pointer_size);
-
-  static MemberOffset EmbeddedImTableOffset(size_t pointer_size);
   static MemberOffset EmbeddedVTableOffset(size_t pointer_size);
-
   template <bool kVisitNativeRoots,
             VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags,
             ReadBarrierOption kReadBarrierOption = kWithReadBarrier,