Revert^2 "Compiler changes for bitstring based type checks."

Add extra output for debugging failures and re-enable
the bitstring type checks.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing --jit
Test: testrunner.py --host -t 670-bitstring-type-check
Test: Pixel 2 XL boots.
Test: testrunner.py --target --optimizing --jit
Test: testrunner.py --target -t 670-bitstring-type-check
Bug: 64692057
Bug: 26687569

This reverts commit bff7a52e2c6c9e988c3ed1f12a2da0fa5fd37cfb.

Change-Id: I090e241983f3ac6ed8394d842e17716087d169ac

1 files changed, 64 insertions, 43 deletions

diff --git a/compiler/optimizing/instruction_builder.cc b/compiler/optimizing/instruction_builder.cc
index c7aef3779d..9647dd5d41 100644
--- a/compiler/optimizing/instruction_builder.cc
+++ b/compiler/optimizing/instruction_builder.cc
@@ -1815,29 +1815,6 @@ void HInstructionBuilder::BuildFillWideArrayData(HInstruction* object,
   }
 }
 
-static TypeCheckKind ComputeTypeCheckKind(Handle<mirror::Class> cls)
-    REQUIRES_SHARED(Locks::mutator_lock_) {
-  if (cls == nullptr) {
-    return TypeCheckKind::kUnresolvedCheck;
-  } else if (cls->IsInterface()) {
-    return TypeCheckKind::kInterfaceCheck;
-  } else if (cls->IsArrayClass()) {
-    if (cls->GetComponentType()->IsObjectClass()) {
-      return TypeCheckKind::kArrayObjectCheck;
-    } else if (cls->CannotBeAssignedFromOtherTypes()) {
-      return TypeCheckKind::kExactCheck;
-    } else {
-      return TypeCheckKind::kArrayCheck;
-    }
-  } else if (cls->IsFinal()) {
-    return TypeCheckKind::kExactCheck;
-  } else if (cls->IsAbstract()) {
-    return TypeCheckKind::kAbstractClassCheck;
-  } else {
-    return TypeCheckKind::kClassHierarchyCheck;
-  }
-}
-
 void HInstructionBuilder::BuildLoadString(dex::StringIndex string_index, uint32_t dex_pc) {
   HLoadString* load_string =
       new (allocator_) HLoadString(graph_->GetCurrentMethod(), string_index, *dex_file_, dex_pc);
@@ -1852,22 +1829,8 @@ void HInstructionBuilder::BuildLoadString(dex::StringIndex string_index, uint32_
 HLoadClass* HInstructionBuilder::BuildLoadClass(dex::TypeIndex type_index, uint32_t dex_pc) {
   ScopedObjectAccess soa(Thread::Current());
   const DexFile& dex_file = *dex_compilation_unit_->GetDexFile();
-  Handle<mirror::ClassLoader> class_loader = dex_compilation_unit_->GetClassLoader();
-  Handle<mirror::Class> klass = handles_->NewHandle(compiler_driver_->ResolveClass(
-      soa, dex_compilation_unit_->GetDexCache(), class_loader, type_index, dex_compilation_unit_));
-
-  bool needs_access_check = true;
-  if (klass != nullptr) {
-    if (klass->IsPublic()) {
-      needs_access_check = false;
-    } else {
-      ObjPtr<mirror::Class> compiling_class = GetCompilingClass();
-      if (compiling_class != nullptr && compiling_class->CanAccess(klass.Get())) {
-        needs_access_check = false;
-      }
-    }
-  }
-
+  Handle<mirror::Class> klass = ResolveClass(soa, type_index);
+  bool needs_access_check = LoadClassNeedsAccessCheck(klass);
   return BuildLoadClass(type_index, dex_file, klass, dex_pc, needs_access_check);
 }
 
@@ -1912,25 +1875,83 @@ HLoadClass* HInstructionBuilder::BuildLoadClass(dex::TypeIndex type_index,
   return load_class;
 }
 
+Handle<mirror::Class> HInstructionBuilder::ResolveClass(ScopedObjectAccess& soa,
+                                                        dex::TypeIndex type_index) {
+  Handle<mirror::ClassLoader> class_loader = dex_compilation_unit_->GetClassLoader();
+  ObjPtr<mirror::Class> klass = compiler_driver_->ResolveClass(
+      soa, dex_compilation_unit_->GetDexCache(), class_loader, type_index, dex_compilation_unit_);
+  // TODO: Avoid creating excessive handles if the method references the same class repeatedly.
+  // (Use a map on the local_allocator_.)
+  return handles_->NewHandle(klass);
+}
+
+bool HInstructionBuilder::LoadClassNeedsAccessCheck(Handle<mirror::Class> klass) {
+  if (klass == nullptr) {
+    return true;
+  } else if (klass->IsPublic()) {
+    return false;
+  } else {
+    ObjPtr<mirror::Class> compiling_class = GetCompilingClass();
+    return compiling_class == nullptr || !compiling_class->CanAccess(klass.Get());
+  }
+}
+
 void HInstructionBuilder::BuildTypeCheck(const Instruction& instruction,
                                          uint8_t destination,
                                          uint8_t reference,
                                          dex::TypeIndex type_index,
                                          uint32_t dex_pc) {
   HInstruction* object = LoadLocal(reference, DataType::Type::kReference);
-  HLoadClass* cls = BuildLoadClass(type_index, dex_pc);
 
   ScopedObjectAccess soa(Thread::Current());
-  TypeCheckKind check_kind = ComputeTypeCheckKind(cls->GetClass());
+  const DexFile& dex_file = *dex_compilation_unit_->GetDexFile();
+  Handle<mirror::Class> klass = ResolveClass(soa, type_index);
+  bool needs_access_check = LoadClassNeedsAccessCheck(klass);
+  TypeCheckKind check_kind = HSharpening::ComputeTypeCheckKind(
+      klass.Get(), code_generator_, compiler_driver_, needs_access_check);
+
+  HInstruction* class_or_null = nullptr;
+  HIntConstant* bitstring_path_to_root = nullptr;
+  HIntConstant* bitstring_mask = nullptr;
+  if (check_kind == TypeCheckKind::kBitstringCheck) {
+    // TODO: Allow using the bitstring check also if we need an access check.
+    DCHECK(!needs_access_check);
+    class_or_null = graph_->GetNullConstant(dex_pc);
+    MutexLock subtype_check_lock(Thread::Current(), *Locks::subtype_check_lock_);
+    uint32_t path_to_root =
+        SubtypeCheck<ObjPtr<mirror::Class>>::GetEncodedPathToRootForTarget(klass.Get());
+    uint32_t mask = SubtypeCheck<ObjPtr<mirror::Class>>::GetEncodedPathToRootMask(klass.Get());
+    bitstring_path_to_root = graph_->GetIntConstant(static_cast<int32_t>(path_to_root), dex_pc);
+    bitstring_mask = graph_->GetIntConstant(static_cast<int32_t>(mask), dex_pc);
+  } else {
+    class_or_null = BuildLoadClass(type_index, dex_file, klass, dex_pc, needs_access_check);
+  }
+  DCHECK(class_or_null != nullptr);
+
   if (instruction.Opcode() == Instruction::INSTANCE_OF) {
-    AppendInstruction(new (allocator_) HInstanceOf(object, cls, check_kind, dex_pc));
+    AppendInstruction(new (allocator_) HInstanceOf(object,
+                                                   class_or_null,
+                                                   check_kind,
+                                                   klass,
+                                                   dex_pc,
+                                                   allocator_,
+                                                   bitstring_path_to_root,
+                                                   bitstring_mask));
     UpdateLocal(destination, current_block_->GetLastInstruction());
   } else {
     DCHECK_EQ(instruction.Opcode(), Instruction::CHECK_CAST);
     // We emit a CheckCast followed by a BoundType. CheckCast is a statement
     // which may throw. If it succeeds BoundType sets the new type of `object`
     // for all subsequent uses.
-    AppendInstruction(new (allocator_) HCheckCast(object, cls, check_kind, dex_pc));
+    AppendInstruction(
+        new (allocator_) HCheckCast(object,
+                                    class_or_null,
+                                    check_kind,
+                                    klass,
+                                    dex_pc,
+                                    allocator_,
+                                    bitstring_path_to_root,
+                                    bitstring_mask));
     AppendInstruction(new (allocator_) HBoundType(object, dex_pc));
     UpdateLocal(reference, current_block_->GetLastInstruction());
   }