Refactor GetIMTIndex

This allows us to more easily maintain and experiment with
interface method table indexing and hashing.

Change-Id: I719920fae7490dcedcda7c1c36db225c2b8b16df
diff --git a/runtime/art_method-inl.h b/runtime/art_method-inl.h
index 7647ad6..9f63bca 100644
--- a/runtime/art_method-inl.h
+++ b/runtime/art_method-inl.h
@@ -120,6 +120,10 @@
   return dex_method_index_;
 }
 
+inline uint32_t ArtMethod::GetImtIndex() {
+  return GetDexMethodIndex() % ImTable::kSize;
+}
+
 inline ArtMethod** ArtMethod::GetDexCacheResolvedMethods(size_t pointer_size) {
   return GetNativePointer<ArtMethod**>(DexCacheResolvedMethodsOffset(pointer_size),
                                        pointer_size);
diff --git a/runtime/art_method.h b/runtime/art_method.h
index b65cb23..2c40d6d 100644
--- a/runtime/art_method.h
+++ b/runtime/art_method.h
@@ -418,6 +418,8 @@
 
   ALWAYS_INLINE uint32_t GetDexMethodIndex() SHARED_REQUIRES(Locks::mutator_lock_);
 
+  ALWAYS_INLINE uint32_t GetImtIndex() SHARED_REQUIRES(Locks::mutator_lock_);
+
   void SetDexMethodIndex(uint32_t new_idx) {
     // Not called within a transaction.
     dex_method_index_ = new_idx;
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 4406c0a..4259aea 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -6167,11 +6167,6 @@
   }
 }
 
-static inline uint32_t GetIMTIndex(ArtMethod* interface_method)
-    SHARED_REQUIRES(Locks::mutator_lock_) {
-  return interface_method->GetDexMethodIndex() % ImTable::kSize;
-}
-
 ImtConflictTable* ClassLinker::CreateImtConflictTable(size_t count,
                                                       LinearAlloc* linear_alloc,
                                                       size_t image_pointer_size) {
@@ -6223,7 +6218,7 @@
       // or interface methods in the IMT here they will not create extra conflicts since we compare
       // names and signatures in SetIMTRef.
       ArtMethod* interface_method = interface->GetVirtualMethod(j, image_pointer_size_);
-      const uint32_t imt_index = GetIMTIndex(interface_method);
+      const uint32_t imt_index = interface_method->GetImtIndex();
 
       // There is only any conflicts if all of the interface methods for an IMT slot don't have
       // the same implementation method, keep track of this to avoid creating a conflict table in
@@ -6277,7 +6272,7 @@
         }
         DCHECK(implementation_method != nullptr);
         ArtMethod* interface_method = interface->GetVirtualMethod(j, image_pointer_size_);
-        const uint32_t imt_index = GetIMTIndex(interface_method);
+        const uint32_t imt_index = interface_method->GetImtIndex();
         if (!imt[imt_index]->IsRuntimeMethod() ||
             imt[imt_index] == unimplemented_method ||
             imt[imt_index] == imt_conflict_method) {
@@ -6683,7 +6678,7 @@
         auto* interface_method = iftable->GetInterface(i)->GetVirtualMethod(j, image_pointer_size_);
         MethodNameAndSignatureComparator interface_name_comparator(
             interface_method->GetInterfaceMethodIfProxy(image_pointer_size_));
-        uint32_t imt_index = GetIMTIndex(interface_method);
+        uint32_t imt_index = interface_method->GetImtIndex();
         ArtMethod** imt_ptr = &out_imt[imt_index];
         // For each method listed in the interface's method list, find the
         // matching method in our class's method list.  We want to favor the
diff --git a/runtime/entrypoints/entrypoint_utils-inl.h b/runtime/entrypoints/entrypoint_utils-inl.h
index 916ca29..db3f88f 100644
--- a/runtime/entrypoints/entrypoint_utils-inl.h
+++ b/runtime/entrypoints/entrypoint_utils-inl.h
@@ -19,7 +19,7 @@
 
 #include "entrypoint_utils.h"
 
-#include "art_method.h"
+#include "art_method-inl.h"
 #include "class_linker-inl.h"
 #include "common_throws.h"
 #include "dex_file.h"
@@ -559,7 +559,7 @@
       }
     }
     case kInterface: {
-      uint32_t imt_index = resolved_method->GetDexMethodIndex() % ImTable::kSize;
+      uint32_t imt_index = resolved_method->GetImtIndex();
       size_t pointer_size = class_linker->GetImagePointerSize();
       ArtMethod* imt_method = (*this_object)->GetClass()->GetImt(pointer_size)->
           Get(imt_index, pointer_size);
diff --git a/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc b/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
index 7175d54..0a70be1 100644
--- a/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
+++ b/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
@@ -2174,8 +2174,7 @@
   if (LIKELY(interface_method->GetDexMethodIndex() != DexFile::kDexNoIndex)) {
     // If the dex cache already resolved the interface method, look whether we have
     // a match in the ImtConflictTable.
-    uint32_t imt_index = interface_method->GetDexMethodIndex();
-    ArtMethod* conflict_method = imt->Get(imt_index % ImTable::kSize, sizeof(void*));
+    ArtMethod* conflict_method = imt->Get(interface_method->GetImtIndex(), sizeof(void*));
     if (LIKELY(conflict_method->IsRuntimeMethod())) {
       ImtConflictTable* current_table = conflict_method->GetImtConflictTable(sizeof(void*));
       DCHECK(current_table != nullptr);
@@ -2226,8 +2225,8 @@
 
   // We arrive here if we have found an implementation, and it is not in the ImtConflictTable.
   // We create a new table with the new pair { interface_method, method }.
-  uint32_t imt_index = interface_method->GetDexMethodIndex();
-  ArtMethod* conflict_method = imt->Get(imt_index % ImTable::kSize, sizeof(void*));
+  uint32_t imt_index = interface_method->GetImtIndex();
+  ArtMethod* conflict_method = imt->Get(imt_index, sizeof(void*));
   if (conflict_method->IsRuntimeMethod()) {
     ArtMethod* new_conflict_method = Runtime::Current()->GetClassLinker()->AddMethodToConflictTable(
         cls.Get(),
@@ -2238,7 +2237,7 @@
     if (new_conflict_method != conflict_method) {
       // Update the IMT if we create a new conflict method. No fence needed here, as the
       // data is consistent.
-      imt->Set(imt_index % ImTable::kSize,
+      imt->Set(imt_index,
                new_conflict_method,
                sizeof(void*));
     }