Use ObjPtr for ResolvedFieldAccessTest and ResolvedMethodAccessTest

Also added LookupResolvedType that is guaranteed to not do thread
suspension but deals with multidex since GetResolvedType will
return null if the type was resolved in another dex file.

Added test.

Bug: 31113334

Test: test-art-host CC baker

Change-Id: I50493bca7d8ce9760546c3116b717484c62c47a4
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 06a8243..0d3c012 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -7638,6 +7638,32 @@
   return string;
 }
 
+ObjPtr<mirror::Class> ClassLinker::LookupResolvedType(const DexFile& dex_file,
+                                                      uint16_t type_idx,
+                                                      ObjPtr<mirror::DexCache> dex_cache,
+                                                      ObjPtr<mirror::ClassLoader> class_loader) {
+  ObjPtr<mirror::Class> type = dex_cache->GetResolvedType(type_idx);
+  if (type == nullptr) {
+    const char* descriptor = dex_file.StringByTypeIdx(type_idx);
+    DCHECK_NE(*descriptor, '\0') << "descriptor is empty string";
+    if (descriptor[1] == '\0') {
+      // only the descriptors of primitive types should be 1 character long, also avoid class lookup
+      // for primitive classes that aren't backed by dex files.
+      type = FindPrimitiveClass(descriptor[0]);
+    } else {
+      Thread* const self = Thread::Current();
+      DCHECK(self != nullptr);
+      const size_t hash = ComputeModifiedUtf8Hash(descriptor);
+      // Find the class in the loaded classes table.
+      type = LookupClass(self, descriptor, hash, class_loader.Decode());
+    }
+  }
+  if (type != nullptr || type->IsResolved()) {
+    return type;
+  }
+  return nullptr;
+}
+
 mirror::Class* ClassLinker::ResolveType(const DexFile& dex_file,
                                         uint16_t type_idx,
                                         mirror::Class* referrer) {
diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index df7fb61..f69a576 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -278,6 +278,14 @@
       REQUIRES_SHARED(Locks::mutator_lock_)
       REQUIRES(!dex_lock_, !Roles::uninterruptible_);
 
+  // Look up a resolved type with the given ID from the DexFile. The ClassLoader is used to search
+  // for the type, since it may be referenced from but not contained within the given DexFile.
+  ObjPtr<mirror::Class> LookupResolvedType(const DexFile& dex_file,
+                                           uint16_t type_idx,
+                                           ObjPtr<mirror::DexCache> dex_cache,
+                                           ObjPtr<mirror::ClassLoader> class_loader)
+      REQUIRES_SHARED(Locks::mutator_lock_);
+
   // Resolve a type with the given ID from the DexFile, storing the
   // result in DexCache. The ClassLoader is used to search for the
   // type, since it may be referenced from but not contained within
diff --git a/runtime/class_linker_test.cc b/runtime/class_linker_test.cc
index 3c12b18..4a926e7 100644
--- a/runtime/class_linker_test.cc
+++ b/runtime/class_linker_test.cc
@@ -865,6 +865,28 @@
   AssertNonExistentClass("[[[[LNonExistentClass;");
 }
 
+TEST_F(ClassLinkerTest, LookupResolvedType) {
+  ScopedObjectAccess soa(Thread::Current());
+  StackHandleScope<1> hs(soa.Self());
+  Handle<mirror::ClassLoader> class_loader(
+      hs.NewHandle(soa.Decode<mirror::ClassLoader>(LoadDex("MyClass"))));
+  AssertNonExistentClass("LMyClass;");
+  ObjPtr<mirror::Class> klass = class_linker_->FindClass(soa.Self(), "LMyClass;", class_loader);
+  uint32_t type_idx = klass->GetClassDef()->class_idx_;
+  ObjPtr<mirror::DexCache> dex_cache = klass->GetDexCache();
+  const DexFile& dex_file = klass->GetDexFile();
+  EXPECT_EQ(dex_cache->GetResolvedType(type_idx), klass.Decode());
+  EXPECT_OBJ_PTR_EQ(
+      class_linker_->LookupResolvedType(dex_file, type_idx, dex_cache, class_loader.Get()),
+      klass);
+  // Zero out the resolved type and make sure LookupResolvedType still finds it.
+  dex_cache->SetResolvedType(type_idx, nullptr);
+  EXPECT_TRUE(dex_cache->GetResolvedType(type_idx) == nullptr);
+  EXPECT_OBJ_PTR_EQ(
+      class_linker_->LookupResolvedType(dex_file, type_idx, dex_cache, class_loader.Get()),
+      klass);
+}
+
 TEST_F(ClassLinkerTest, LibCore) {
   ScopedObjectAccess soa(Thread::Current());
   ASSERT_TRUE(java_lang_dex_file_ != nullptr);
diff --git a/runtime/mirror/class-inl.h b/runtime/mirror/class-inl.h
index 8aebd6e..3cbd58b 100644
--- a/runtime/mirror/class-inl.h
+++ b/runtime/mirror/class-inl.h
@@ -362,36 +362,29 @@
 }
 
 template <bool throw_on_failure, bool use_referrers_cache>
-inline bool Class::ResolvedFieldAccessTest(Class* access_to,
+inline bool Class::ResolvedFieldAccessTest(ObjPtr<Class> access_to,
                                            ArtField* field,
                                            uint32_t field_idx,
-                                           DexCache* dex_cache) {
+                                           ObjPtr<DexCache> dex_cache) {
   DCHECK_EQ(use_referrers_cache, dex_cache == nullptr);
   if (UNLIKELY(!this->CanAccess(access_to))) {
     // The referrer class can't access the field's declaring class but may still be able
     // to access the field if the FieldId specifies an accessible subclass of the declaring
     // class rather than the declaring class itself.
-    DexCache* referrer_dex_cache = use_referrers_cache ? this->GetDexCache() : dex_cache;
+    ObjPtr<DexCache> referrer_dex_cache = use_referrers_cache ? this->GetDexCache() : dex_cache;
     uint32_t class_idx = referrer_dex_cache->GetDexFile()->GetFieldId(field_idx).class_idx_;
     // The referenced class has already been resolved with the field, but may not be in the dex
-    // cache. Using ResolveType here without handles in the caller should be safe since there
+    // cache. Use LookupResolveType here to search the class table if it is not in the dex cache.
     // should be no thread suspension due to the class being resolved.
-    // TODO: Clean this up to use handles in the caller.
-    Class* dex_access_to;
-    {
-      StackHandleScope<2> hs(Thread::Current());
-      Handle<mirror::DexCache> h_dex_cache(hs.NewHandle(referrer_dex_cache));
-      Handle<mirror::ClassLoader> h_class_loader(hs.NewHandle(access_to->GetClassLoader()));
-      dex_access_to = Runtime::Current()->GetClassLinker()->ResolveType(
-          *referrer_dex_cache->GetDexFile(),
-          class_idx,
-          h_dex_cache,
-          h_class_loader);
-    }
+    ObjPtr<Class> dex_access_to = Runtime::Current()->GetClassLinker()->LookupResolvedType(
+        *referrer_dex_cache->GetDexFile(),
+        class_idx,
+        referrer_dex_cache,
+        access_to->GetClassLoader());
     DCHECK(dex_access_to != nullptr);
     if (UNLIKELY(!this->CanAccess(dex_access_to))) {
       if (throw_on_failure) {
-        ThrowIllegalAccessErrorClass(this, dex_access_to);
+        ThrowIllegalAccessErrorClass(this, dex_access_to.Decode());
       }
       return false;
     }
@@ -406,36 +399,32 @@
 }
 
 template <bool throw_on_failure, bool use_referrers_cache, InvokeType throw_invoke_type>
-inline bool Class::ResolvedMethodAccessTest(Class* access_to, ArtMethod* method,
-                                            uint32_t method_idx, DexCache* dex_cache) {
+inline bool Class::ResolvedMethodAccessTest(ObjPtr<Class> access_to,
+                                            ArtMethod* method,
+                                            uint32_t method_idx,
+                                            ObjPtr<DexCache> dex_cache) {
   static_assert(throw_on_failure || throw_invoke_type == kStatic, "Non-default throw invoke type");
   DCHECK_EQ(use_referrers_cache, dex_cache == nullptr);
   if (UNLIKELY(!this->CanAccess(access_to))) {
     // The referrer class can't access the method's declaring class but may still be able
     // to access the method if the MethodId specifies an accessible subclass of the declaring
     // class rather than the declaring class itself.
-    DexCache* referrer_dex_cache = use_referrers_cache ? this->GetDexCache() : dex_cache;
+    ObjPtr<DexCache> referrer_dex_cache = use_referrers_cache ? this->GetDexCache() : dex_cache;
     uint32_t class_idx = referrer_dex_cache->GetDexFile()->GetMethodId(method_idx).class_idx_;
     // The referenced class has already been resolved with the method, but may not be in the dex
-    // cache. Using ResolveType here without handles in the caller should be safe since there
-    // should be no thread suspension due to the class being resolved.
-    // TODO: Clean this up to use handles in the caller.
-    Class* dex_access_to;
-    {
-      StackHandleScope<2> hs(Thread::Current());
-      Handle<mirror::DexCache> h_dex_cache(hs.NewHandle(referrer_dex_cache));
-      Handle<mirror::ClassLoader> h_class_loader(hs.NewHandle(access_to->GetClassLoader()));
-      dex_access_to = Runtime::Current()->GetClassLinker()->ResolveType(
-          *referrer_dex_cache->GetDexFile(),
-          class_idx,
-          h_dex_cache,
-          h_class_loader);
-    }
+    // cache.
+    ObjPtr<Class> dex_access_to = Runtime::Current()->GetClassLinker()->LookupResolvedType(
+        *referrer_dex_cache->GetDexFile(),
+        class_idx,
+        referrer_dex_cache,
+        access_to->GetClassLoader());
     DCHECK(dex_access_to != nullptr);
     if (UNLIKELY(!this->CanAccess(dex_access_to))) {
       if (throw_on_failure) {
-        ThrowIllegalAccessErrorClassForMethodDispatch(this, dex_access_to,
-                                                      method, throw_invoke_type);
+        ThrowIllegalAccessErrorClassForMethodDispatch(this,
+                                                      dex_access_to.Decode(),
+                                                      method,
+                                                      throw_invoke_type);
       }
       return false;
     }
@@ -453,10 +442,7 @@
                                           ArtField* field,
                                           ObjPtr<DexCache> dex_cache,
                                           uint32_t field_idx) {
-  return ResolvedFieldAccessTest<false, false>(access_to.Decode(),
-                                               field,
-                                               field_idx,
-                                               dex_cache.Decode());
+  return ResolvedFieldAccessTest<false, false>(access_to, field, field_idx, dex_cache);
 }
 
 inline bool Class::CheckResolvedFieldAccess(ObjPtr<Class> access_to,
diff --git a/runtime/mirror/class.h b/runtime/mirror/class.h
index d38f235..a0d6f37 100644
--- a/runtime/mirror/class.h
+++ b/runtime/mirror/class.h
@@ -1287,14 +1287,17 @@
   void SetVerifyError(Object* klass) REQUIRES_SHARED(Locks::mutator_lock_);
 
   template <bool throw_on_failure, bool use_referrers_cache>
-  bool ResolvedFieldAccessTest(Class* access_to,
+  bool ResolvedFieldAccessTest(ObjPtr<Class> access_to,
                                ArtField* field,
                                uint32_t field_idx,
-                               DexCache* dex_cache)
+                               ObjPtr<DexCache> dex_cache)
       REQUIRES_SHARED(Locks::mutator_lock_);
+
   template <bool throw_on_failure, bool use_referrers_cache, InvokeType throw_invoke_type>
-  bool ResolvedMethodAccessTest(Class* access_to, ArtMethod* resolved_method,
-                                uint32_t method_idx, DexCache* dex_cache)
+  bool ResolvedMethodAccessTest(ObjPtr<Class> access_to,
+                                ArtMethod* resolved_method,
+                                uint32_t method_idx,
+                                ObjPtr<DexCache> dex_cache)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   bool Implements(Class* klass) REQUIRES_SHARED(Locks::mutator_lock_);