Change dex caches to be weak roots

Changed dex caches to be weak roots. This is necessary for class
unloading since the resolved types arrays would keep classes live
when they should be unloaded. Currently the dex caches still don't
get freed due to the class loader roots.

Also deleted some unused functionality in image writer.

Bug: 22720414
Change-Id: If22cb3cad7e3baabc8158a77d7f20799faf4c341

1 files changed, 16 insertions, 14 deletions

diff --git a/compiler/driver/compiler_driver.cc b/compiler/driver/compiler_driver.cc
index fa25a17481..d38677e62c 100644
--- a/compiler/driver/compiler_driver.cc
+++ b/compiler/driver/compiler_driver.cc
@@ -936,7 +936,7 @@ void CompilerDriver::LoadImageClasses(TimingLogger* timings) {
       uint16_t exception_type_idx = exception_type.first;
       const DexFile* dex_file = exception_type.second;
       StackHandleScope<2> hs2(self);
-      Handle<mirror::DexCache> dex_cache(hs2.NewHandle(class_linker->FindDexCache(*dex_file)));
+      Handle<mirror::DexCache> dex_cache(hs2.NewHandle(class_linker->RegisterDexFile(*dex_file)));
       Handle<mirror::Class> klass(hs2.NewHandle(
           class_linker->ResolveType(*dex_file, exception_type_idx, dex_cache,
                                     NullHandle<mirror::ClassLoader>())));
@@ -1170,7 +1170,8 @@ bool CompilerDriver::CanAssumeTypeIsPresentInDexCache(const DexFile& dex_file, u
       IsImageClass(dex_file.StringDataByIdx(dex_file.GetTypeId(type_idx).descriptor_idx_))) {
     {
       ScopedObjectAccess soa(Thread::Current());
-      mirror::DexCache* dex_cache = Runtime::Current()->GetClassLinker()->FindDexCache(dex_file);
+      mirror::DexCache* dex_cache = Runtime::Current()->GetClassLinker()->FindDexCache(
+          dex_file, false);
       mirror::Class* resolved_class = dex_cache->GetResolvedType(type_idx);
       if (resolved_class == nullptr) {
         // Erroneous class.
@@ -1195,9 +1196,9 @@ bool CompilerDriver::CanAssumeStringIsPresentInDexCache(const DexFile& dex_file,
     // We resolve all const-string strings when building for the image.
     ScopedObjectAccess soa(Thread::Current());
     StackHandleScope<1> hs(soa.Self());
-    Handle<mirror::DexCache> dex_cache(
-        hs.NewHandle(Runtime::Current()->GetClassLinker()->FindDexCache(dex_file)));
-    Runtime::Current()->GetClassLinker()->ResolveString(dex_file, string_idx, dex_cache);
+    ClassLinker* const class_linker = Runtime::Current()->GetClassLinker();
+    Handle<mirror::DexCache> dex_cache(hs.NewHandle(class_linker->FindDexCache(dex_file, false)));
+    class_linker->ResolveString(dex_file, string_idx, dex_cache);
     result = true;
   }
   if (result) {
@@ -1222,7 +1223,7 @@ bool CompilerDriver::CanAccessTypeWithoutChecks(uint32_t referrer_idx, const Dex
     *equals_referrers_class = false;
   }
   ScopedObjectAccess soa(Thread::Current());
-  mirror::DexCache* dex_cache = Runtime::Current()->GetClassLinker()->FindDexCache(dex_file);
+  mirror::DexCache* dex_cache = Runtime::Current()->GetClassLinker()->FindDexCache(dex_file, false);
   // Get type from dex cache assuming it was populated by the verifier
   mirror::Class* resolved_class = dex_cache->GetResolvedType(type_idx);
   if (resolved_class == nullptr) {
@@ -1259,7 +1260,8 @@ bool CompilerDriver::CanAccessInstantiableTypeWithoutChecks(uint32_t referrer_id
                                                             const DexFile& dex_file,
                                                             uint32_t type_idx) {
   ScopedObjectAccess soa(Thread::Current());
-  mirror::DexCache* dex_cache = Runtime::Current()->GetClassLinker()->FindDexCache(dex_file);
+  mirror::DexCache* dex_cache = Runtime::Current()->GetClassLinker()->FindDexCache(
+      dex_file, false);
   // Get type from dex cache assuming it was populated by the verifier.
   mirror::Class* resolved_class = dex_cache->GetResolvedType(type_idx);
   if (resolved_class == nullptr) {
@@ -1288,7 +1290,7 @@ bool CompilerDriver::CanEmbedTypeInCode(const DexFile& dex_file, uint32_t type_i
                                         uintptr_t* direct_type_ptr, bool* out_is_finalizable) {
   ScopedObjectAccess soa(Thread::Current());
   Runtime* runtime = Runtime::Current();
-  mirror::DexCache* dex_cache = runtime->GetClassLinker()->FindDexCache(dex_file);
+  mirror::DexCache* dex_cache = runtime->GetClassLinker()->FindDexCache(dex_file, false);
   mirror::Class* resolved_class = dex_cache->GetResolvedType(type_idx);
   if (resolved_class == nullptr) {
     return false;
@@ -1417,7 +1419,7 @@ ArtField* CompilerDriver::ComputeInstanceFieldInfo(uint32_t field_idx,
   {
     StackHandleScope<2> hs(soa.Self());
     Handle<mirror::DexCache> dex_cache_handle(
-        hs.NewHandle(mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile())));
+        hs.NewHandle(mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile(), false)));
     Handle<mirror::ClassLoader> class_loader_handle(
         hs.NewHandle(soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader())));
     resolved_field =
@@ -1467,7 +1469,7 @@ bool CompilerDriver::ComputeStaticFieldInfo(uint32_t field_idx, const DexCompila
   {
     StackHandleScope<2> hs(soa.Self());
     Handle<mirror::DexCache> dex_cache_handle(
-        hs.NewHandle(mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile())));
+        hs.NewHandle(mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile(), false)));
     Handle<mirror::ClassLoader> class_loader_handle(
         hs.NewHandle(soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader())));
     resolved_field =
@@ -1653,7 +1655,7 @@ bool CompilerDriver::ComputeInvokeInfo(const DexCompilationUnit* mUnit, const ui
   // Try to resolve the method and compiling method's class.
   StackHandleScope<3> hs(soa.Self());
   Handle<mirror::DexCache> dex_cache(
-      hs.NewHandle(mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile())));
+      hs.NewHandle(mUnit->GetClassLinker()->FindDexCache(*mUnit->GetDexFile(), false)));
   Handle<mirror::ClassLoader> class_loader(hs.NewHandle(
       soa.Decode<mirror::ClassLoader*>(mUnit->GetClassLoader())));
   uint32_t method_idx = target_method->dex_method_index;
@@ -1905,7 +1907,7 @@ class ResolveClassFieldsAndMethodsVisitor : public CompilationVisitor {
     StackHandleScope<2> hs(soa.Self());
     Handle<mirror::ClassLoader> class_loader(
         hs.NewHandle(soa.Decode<mirror::ClassLoader*>(jclass_loader)));
-    Handle<mirror::DexCache> dex_cache(hs.NewHandle(class_linker->FindDexCache(dex_file)));
+    Handle<mirror::DexCache> dex_cache(hs.NewHandle(class_linker->FindDexCache(dex_file, false)));
     // Resolve the class.
     mirror::Class* klass = class_linker->ResolveType(dex_file, class_def.class_idx_, dex_cache,
                                                      class_loader);
@@ -1998,7 +2000,7 @@ class ResolveTypeVisitor : public CompilationVisitor {
     ClassLinker* class_linker = manager_->GetClassLinker();
     const DexFile& dex_file = *manager_->GetDexFile();
     StackHandleScope<2> hs(soa.Self());
-    Handle<mirror::DexCache> dex_cache(hs.NewHandle(class_linker->FindDexCache(dex_file)));
+    Handle<mirror::DexCache> dex_cache(hs.NewHandle(class_linker->RegisterDexFile(dex_file)));
     Handle<mirror::ClassLoader> class_loader(
         hs.NewHandle(soa.Decode<mirror::ClassLoader*>(manager_->GetClassLoader())));
     mirror::Class* klass = class_linker->ResolveType(dex_file, type_idx, dex_cache, class_loader);
@@ -2084,7 +2086,7 @@ class VerifyClassVisitor : public CompilationVisitor {
        * 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.
        */
-      Handle<mirror::DexCache> dex_cache(hs.NewHandle(class_linker->FindDexCache(dex_file)));
+      Handle<mirror::DexCache> dex_cache(hs.NewHandle(class_linker->FindDexCache(dex_file, false)));
       std::string error_msg;
       if (verifier::MethodVerifier::VerifyClass(soa.Self(), &dex_file, dex_cache, class_loader,
                                                 &class_def, true, &error_msg) ==