Compacting collector.

The compacting collector is currently similar to semispace. It works by
copying objects back and forth between two bump pointer spaces. There
are types of objects which are "non-movable" due to current runtime
limitations. These are Classes, Methods, and Fields.

Bump pointer spaces are a new type of continuous alloc space which have
no lock in the allocation code path. When you allocate from these it uses
atomic operations to increase an index. Traversing the objects in the bump
pointer space relies on Object::SizeOf matching the allocated size exactly.

Runtime changes:
JNI::GetArrayElements returns copies objects if you attempt to get the
backing data of a movable array. For GetArrayElementsCritical, we return
direct backing storage for any types of arrays, but temporarily disable
the GC until the critical region is completed.

Added a new runtime call called VisitObjects, this is used in place of
the old pattern which was flushing the allocation stack and walking
the bitmaps.

Changed image writer to be compaction safe and use object monitor word
for forwarding addresses.

Added a bunch of added SIRTs to ClassLinker, MethodLinker, etc..

TODO: Enable switching allocators, compacting on background, etc..

Bug: 8981901

Change-Id: I3c886fd322a6eef2b99388d19a765042ec26ab99

1 files changed, 48 insertions, 49 deletions

diff --git a/compiler/driver/compiler_driver.cc b/compiler/driver/compiler_driver.cc
index 9cc94e8c0d..4af492bf6e 100644
--- a/compiler/driver/compiler_driver.cc
+++ b/compiler/driver/compiler_driver.cc
@@ -513,10 +513,9 @@ void CompilerDriver::CompileAll(jobject class_loader,
   }
 }
 
-static DexToDexCompilationLevel GetDexToDexCompilationlevel(mirror::ClassLoader* class_loader,
-                                                            const DexFile& dex_file,
-                                                            const DexFile::ClassDef& class_def)
-    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+static DexToDexCompilationLevel GetDexToDexCompilationlevel(
+    SirtRef<mirror::ClassLoader>& class_loader, const DexFile& dex_file,
+    const DexFile::ClassDef& class_def) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   const char* descriptor = dex_file.GetClassDescriptor(class_def);
   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
   mirror::Class* klass = class_linker->FindClass(descriptor, class_loader);
@@ -531,7 +530,7 @@ static DexToDexCompilationLevel GetDexToDexCompilationlevel(mirror::ClassLoader*
   // function). Since image classes can be verified again while compiling an application,
   // we must prevent the DEX-to-DEX compiler from introducing them.
   // TODO: find a way to enable "quick" instructions for image classes and remove this check.
-  bool compiling_image_classes = (class_loader == NULL);
+  bool compiling_image_classes = class_loader.get() == nullptr;
   if (compiling_image_classes) {
     return kRequired;
   } else if (klass->IsVerified()) {
@@ -579,7 +578,8 @@ void CompilerDriver::CompileOne(const mirror::ArtMethod* method, base::TimingLog
   {
     ScopedObjectAccess soa(Thread::Current());
     const DexFile::ClassDef& class_def = dex_file->GetClassDef(class_def_idx);
-    mirror::ClassLoader* class_loader = soa.Decode<mirror::ClassLoader*>(jclass_loader);
+    SirtRef<mirror::ClassLoader> class_loader(soa.Self(),
+                                              soa.Decode<mirror::ClassLoader*>(jclass_loader));
     dex_to_dex_compilation_level = GetDexToDexCompilationlevel(class_loader, *dex_file, class_def);
   }
   CompileMethod(code_item, method->GetAccessFlags(), method->GetInvokeType(),
@@ -721,8 +721,8 @@ void CompilerDriver::LoadImageClasses(base::TimingLogger& timings)
     for (const std::pair<uint16_t, const DexFile*>& exception_type : unresolved_exception_types) {
       uint16_t exception_type_idx = exception_type.first;
       const DexFile* dex_file = exception_type.second;
-      mirror::DexCache* dex_cache = class_linker->FindDexCache(*dex_file);
-      mirror:: ClassLoader* class_loader = NULL;
+      SirtRef<mirror::DexCache> dex_cache(self, class_linker->FindDexCache(*dex_file));
+      SirtRef<mirror::ClassLoader> class_loader(self, nullptr);
       SirtRef<mirror::Class> klass(self, class_linker->ResolveType(*dex_file, exception_type_idx,
                                                                    dex_cache, class_loader));
       if (klass.get() == NULL) {
@@ -782,15 +782,14 @@ void CompilerDriver::UpdateImageClasses(base::TimingLogger& timings) {
     const char* old_cause = self->StartAssertNoThreadSuspension("ImageWriter");
     gc::Heap* heap = Runtime::Current()->GetHeap();
     // TODO: Image spaces only?
+    ScopedObjectAccess soa(Thread::Current());
     WriterMutexLock mu(self, *Locks::heap_bitmap_lock_);
-    heap->FlushAllocStack();
-    heap->GetLiveBitmap()->Walk(FindClinitImageClassesCallback, this);
+    heap->VisitObjects(FindClinitImageClassesCallback, this);
     self->EndAssertNoThreadSuspension(old_cause);
   }
 }
 
-bool CompilerDriver::CanAssumeTypeIsPresentInDexCache(const DexFile& dex_file,
-                                                      uint32_t type_idx) {
+bool CompilerDriver::CanAssumeTypeIsPresentInDexCache(const DexFile& dex_file, uint32_t type_idx) {
   if (IsImage() &&
       IsImageClass(dex_file.StringDataByIdx(dex_file.GetTypeId(type_idx).descriptor_idx_))) {
     if (kIsDebugBuild) {
@@ -815,7 +814,7 @@ bool CompilerDriver::CanAssumeStringIsPresentInDexCache(const DexFile& dex_file,
   if (IsImage()) {
     // We resolve all const-string strings when building for the image.
     ScopedObjectAccess soa(Thread::Current());
-    mirror::DexCache* dex_cache = Runtime::Current()->GetClassLinker()->FindDexCache(dex_file);
+    SirtRef<mirror::DexCache> dex_cache(soa.Self(), Runtime::Current()->GetClassLinker()->FindDexCache(dex_file));
     Runtime::Current()->GetClassLinker()->ResolveString(dex_file, string_idx, dex_cache);
     result = true;
   }
@@ -903,26 +902,27 @@ bool CompilerDriver::CanAccessInstantiableTypeWithoutChecks(uint32_t referrer_id
 }
 
 static mirror::Class* ComputeCompilingMethodsClass(ScopedObjectAccess& soa,
-                                                   mirror::DexCache* dex_cache,
+                                                   SirtRef<mirror::DexCache>& dex_cache,
                                                    const DexCompilationUnit* mUnit)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
   // The passed dex_cache is a hint, sanity check before asking the class linker that will take a
   // lock.
   if (dex_cache->GetDexFile() != mUnit->GetDexFile()) {
-    dex_cache = mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile());
+    dex_cache.reset(mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile()));
   }
-  mirror::ClassLoader* class_loader = soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader());
-  const DexFile::MethodId& referrer_method_id = mUnit->GetDexFile()->GetMethodId(mUnit->GetDexMethodIndex());
+  SirtRef<mirror::ClassLoader>
+      class_loader(soa.Self(), soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader()));
+  const DexFile::MethodId& referrer_method_id =
+      mUnit->GetDexFile()->GetMethodId(mUnit->GetDexMethodIndex());
   return mUnit->GetClassLinker()->ResolveType(*mUnit->GetDexFile(), referrer_method_id.class_idx_,
                                               dex_cache, class_loader);
 }
 
-static mirror::ArtField* ComputeFieldReferencedFromCompilingMethod(ScopedObjectAccess& soa,
-                                                                const DexCompilationUnit* mUnit,
-                                                                uint32_t field_idx)
+static mirror::ArtField* ComputeFieldReferencedFromCompilingMethod(
+    ScopedObjectAccess& soa, const DexCompilationUnit* mUnit, uint32_t field_idx)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-  mirror::DexCache* dex_cache = mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile());
-  mirror::ClassLoader* class_loader = soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader());
+  SirtRef<mirror::DexCache> dex_cache(soa.Self(), mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile()));
+  SirtRef<mirror::ClassLoader> class_loader(soa.Self(), soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader()));
   return mUnit->GetClassLinker()->ResolveField(*mUnit->GetDexFile(), field_idx, dex_cache,
                                                class_loader, false);
 }
@@ -932,8 +932,8 @@ static mirror::ArtMethod* ComputeMethodReferencedFromCompilingMethod(ScopedObjec
                                                                      uint32_t method_idx,
                                                                      InvokeType type)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-  mirror::DexCache* dex_cache = mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile());
-  mirror::ClassLoader* class_loader = soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader());
+  SirtRef<mirror::DexCache> dex_cache(soa.Self(), mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile()));
+  SirtRef<mirror::ClassLoader> class_loader(soa.Self(), soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader()));
   return mUnit->GetClassLinker()->ResolveMethod(*mUnit->GetDexFile(), method_idx, dex_cache,
                                                 class_loader, NULL, type);
 }
@@ -947,9 +947,10 @@ bool CompilerDriver::ComputeInstanceFieldInfo(uint32_t field_idx, const DexCompi
   // Try to resolve field and ignore if an Incompatible Class Change Error (ie is static).
   mirror::ArtField* resolved_field = ComputeFieldReferencedFromCompilingMethod(soa, mUnit, field_idx);
   if (resolved_field != NULL && !resolved_field->IsStatic()) {
+    SirtRef<mirror::DexCache> dex_cache(soa.Self(),
+                                        resolved_field->GetDeclaringClass()->GetDexCache());
     mirror::Class* referrer_class =
-        ComputeCompilingMethodsClass(soa, resolved_field->GetDeclaringClass()->GetDexCache(),
-                                     mUnit);
+        ComputeCompilingMethodsClass(soa, dex_cache, mUnit);
     if (referrer_class != NULL) {
       mirror::Class* fields_class = resolved_field->GetDeclaringClass();
       bool access_ok = referrer_class->CanAccess(fields_class) &&
@@ -997,9 +998,9 @@ bool CompilerDriver::ComputeStaticFieldInfo(uint32_t field_idx, const DexCompila
   // Try to resolve field and ignore if an Incompatible Class Change Error (ie isn't static).
   mirror::ArtField* resolved_field = ComputeFieldReferencedFromCompilingMethod(soa, mUnit, field_idx);
   if (resolved_field != NULL && resolved_field->IsStatic()) {
+    SirtRef<mirror::DexCache> dex_cache(soa.Self(), resolved_field->GetDeclaringClass()->GetDexCache());
     mirror::Class* referrer_class =
-        ComputeCompilingMethodsClass(soa, resolved_field->GetDeclaringClass()->GetDexCache(),
-                                     mUnit);
+        ComputeCompilingMethodsClass(soa, dex_cache, mUnit);
     if (referrer_class != NULL) {
       mirror::Class* fields_class = resolved_field->GetDeclaringClass();
       if (fields_class == referrer_class) {
@@ -1085,7 +1086,7 @@ void CompilerDriver::GetCodeAndMethodForDirectCall(InvokeType* type, InvokeType
   *direct_code = 0;
   *direct_method = 0;
   bool use_dex_cache = false;
-  bool compiling_boot = Runtime::Current()->GetHeap()->GetContinuousSpaces().size() == 1;
+  const bool compiling_boot = Runtime::Current()->GetHeap()->IsCompilingBoot();
   if (compiler_backend_ == kPortable) {
     if (sharp_type != kStatic && sharp_type != kDirect) {
       return;
@@ -1198,9 +1199,9 @@ bool CompilerDriver::ComputeInvokeInfo(const DexCompilationUnit* mUnit, const ui
     }
     // Don't try to fast-path if we don't understand the caller's class or this appears to be an
     // Incompatible Class Change Error.
+    SirtRef<mirror::DexCache> dex_cache(soa.Self(), resolved_method->GetDeclaringClass()->GetDexCache());
     mirror::Class* referrer_class =
-        ComputeCompilingMethodsClass(soa, resolved_method->GetDeclaringClass()->GetDexCache(),
-                                     mUnit);
+        ComputeCompilingMethodsClass(soa, dex_cache, mUnit);
     bool icce = resolved_method->CheckIncompatibleClassChange(*invoke_type);
     if (referrer_class != NULL && !icce) {
       mirror::Class* methods_class = resolved_method->GetDeclaringClass();
@@ -1254,10 +1255,8 @@ bool CompilerDriver::ComputeInvokeInfo(const DexCompilationUnit* mUnit, const ui
           const MethodReference* devirt_map_target =
               verifier::MethodVerifier::GetDevirtMap(caller_method, dex_pc);
           if (devirt_map_target != NULL) {
-            mirror::DexCache* target_dex_cache =
-                mUnit->GetClassLinker()->FindDexCache(*devirt_map_target->dex_file);
-            mirror::ClassLoader* class_loader =
-                soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader());
+            SirtRef<mirror::DexCache> target_dex_cache(soa.Self(), mUnit->GetClassLinker()->FindDexCache(*devirt_map_target->dex_file));
+            SirtRef<mirror::ClassLoader> class_loader(soa.Self(), soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader()));
             mirror::ArtMethod* called_method =
                 mUnit->GetClassLinker()->ResolveMethod(*devirt_map_target->dex_file,
                                                        devirt_map_target->dex_method_index,
@@ -1509,13 +1508,11 @@ static void ResolveClassFieldsAndMethods(const ParallelCompilationManager* manag
   const DexFile::ClassDef& class_def = dex_file.GetClassDef(class_def_index);
   if (!SkipClass(class_linker, jclass_loader, dex_file, class_def)) {
     ScopedObjectAccess soa(self);
-    mirror::ClassLoader* class_loader = soa.Decode<mirror::ClassLoader*>(jclass_loader);
-    mirror::DexCache* dex_cache = class_linker->FindDexCache(dex_file);
-
+    SirtRef<mirror::ClassLoader> class_loader(soa.Self(), soa.Decode<mirror::ClassLoader*>(jclass_loader));
+    SirtRef<mirror::DexCache> dex_cache(soa.Self(), class_linker->FindDexCache(dex_file));
     // Resolve the class.
     mirror::Class* klass = class_linker->ResolveType(dex_file, class_def.class_idx_, dex_cache,
                                                      class_loader);
-
     bool resolve_fields_and_methods;
     if (klass == NULL) {
       // Class couldn't be resolved, for example, super-class is in a different dex file. Don't
@@ -1598,8 +1595,8 @@ static void ResolveType(const ParallelCompilationManager* manager, size_t type_i
   ScopedObjectAccess soa(Thread::Current());
   ClassLinker* class_linker = manager->GetClassLinker();
   const DexFile& dex_file = *manager->GetDexFile();
-  mirror::DexCache* dex_cache = class_linker->FindDexCache(dex_file);
-  mirror::ClassLoader* class_loader = soa.Decode<mirror::ClassLoader*>(manager->GetClassLoader());
+  SirtRef<mirror::DexCache> dex_cache(soa.Self(), class_linker->FindDexCache(dex_file));
+  SirtRef<mirror::ClassLoader> class_loader(soa.Self(), soa.Decode<mirror::ClassLoader*>(manager->GetClassLoader()));
   mirror::Class* klass = class_linker->ResolveType(dex_file, type_idx, dex_cache, class_loader);
 
   if (klass == NULL) {
@@ -1652,8 +1649,9 @@ static void VerifyClass(const ParallelCompilationManager* manager, size_t class_
   const char* descriptor = dex_file.GetClassDescriptor(class_def);
   ClassLinker* class_linker = manager->GetClassLinker();
   jobject jclass_loader = manager->GetClassLoader();
-  mirror::Class* klass = class_linker->FindClass(descriptor,
-                                                 soa.Decode<mirror::ClassLoader*>(jclass_loader));
+  SirtRef<mirror::ClassLoader> class_loader(
+      soa.Self(), soa.Decode<mirror::ClassLoader*>(jclass_loader));
+  mirror::Class* klass = class_linker->FindClass(descriptor, class_loader);
   if (klass == NULL) {
     CHECK(soa.Self()->IsExceptionPending());
     soa.Self()->ClearException();
@@ -1663,11 +1661,10 @@ static void VerifyClass(const ParallelCompilationManager* manager, size_t class_
      * This is to ensure the class is structurally sound for compilation. An unsound class
      * will be rejected by the verifier and later skipped during compilation in the compiler.
      */
-    mirror::DexCache* dex_cache = class_linker->FindDexCache(dex_file);
+    SirtRef<mirror::DexCache> dex_cache(soa.Self(), class_linker->FindDexCache(dex_file));
     std::string error_msg;
-    if (verifier::MethodVerifier::VerifyClass(&dex_file, dex_cache,
-                                              soa.Decode<mirror::ClassLoader*>(jclass_loader),
-                                              &class_def, true, &error_msg) ==
+    if (verifier::MethodVerifier::VerifyClass(&dex_file, dex_cache, class_loader, &class_def, true,
+                                              &error_msg) ==
                                                   verifier::MethodVerifier::kHardFailure) {
       LOG(ERROR) << "Verification failed on class " << PrettyDescriptor(descriptor)
                  << " because: " << error_msg;
@@ -2124,7 +2121,8 @@ static void InitializeClass(const ParallelCompilationManager* manager, size_t cl
   const char* descriptor = dex_file.StringDataByIdx(class_type_id.descriptor_idx_);
 
   ScopedObjectAccess soa(Thread::Current());
-  mirror::ClassLoader* class_loader = soa.Decode<mirror::ClassLoader*>(jclass_loader);
+  SirtRef<mirror::ClassLoader> class_loader(soa.Self(),
+                                            soa.Decode<mirror::ClassLoader*>(jclass_loader));
   mirror::Class* klass = manager->GetClassLinker()->FindClass(descriptor, class_loader);
 
   if (klass != NULL && !SkipClass(jclass_loader, dex_file, klass)) {
@@ -2253,7 +2251,8 @@ void CompilerDriver::CompileClass(const ParallelCompilationManager* manager, siz
   DexToDexCompilationLevel dex_to_dex_compilation_level = kDontDexToDexCompile;
   {
     ScopedObjectAccess soa(Thread::Current());
-    mirror::ClassLoader* class_loader = soa.Decode<mirror::ClassLoader*>(jclass_loader);
+    SirtRef<mirror::ClassLoader> class_loader(soa.Self(),
+                                              soa.Decode<mirror::ClassLoader*>(jclass_loader));
     dex_to_dex_compilation_level = GetDexToDexCompilationlevel(class_loader, dex_file, class_def);
   }
   ClassDataItemIterator it(dex_file, class_data);