Revert^4 "Compiler changes for bitstring based type checks."

Disabled the build time flag. (No image version bump needed.)

Bug: 26687569
Bug: 64692057
Bug: 76420366

This reverts commit 3fbd3ad99fad077e5c760e7238bcd55b07d4c06e.

Change-Id: I5d83c4ce8a7331c435d5155ac6e0ce1c77d60004

1 files changed, 69 insertions, 0 deletions

diff --git a/compiler/optimizing/sharpening.cc b/compiler/optimizing/sharpening.cc
index 7dffb2a378..70b45763af 100644
--- a/compiler/optimizing/sharpening.cc
+++ b/compiler/optimizing/sharpening.cc
@@ -240,6 +240,75 @@ HLoadClass::LoadKind HSharpening::ComputeLoadClassKind(
   return load_kind;
 }
 
+static inline bool CanUseTypeCheckBitstring(ObjPtr<mirror::Class> klass,
+                                            CodeGenerator* codegen,
+                                            CompilerDriver* compiler_driver)
+    REQUIRES_SHARED(Locks::mutator_lock_) {
+  DCHECK(!klass->IsProxyClass());
+  DCHECK(!klass->IsArrayClass());
+
+  if (Runtime::Current()->UseJitCompilation()) {
+    // If we're JITting, try to assign a type check bitstring (fall through).
+  } else if (codegen->GetCompilerOptions().IsBootImage()) {
+    const char* descriptor = klass->GetDexFile().StringByTypeIdx(klass->GetDexTypeIndex());
+    if (!compiler_driver->IsImageClass(descriptor)) {
+      return false;
+    }
+    // If the target is a boot image class, try to assign a type check bitstring (fall through).
+    // (If --force-determinism, this was already done; repeating is OK and yields the same result.)
+  } else {
+    // TODO: Use the bitstring also for AOT app compilation if the target class has a bitstring
+    // already assigned in the boot image.
+    return false;
+  }
+
+  // Try to assign a type check bitstring.
+  MutexLock subtype_check_lock(Thread::Current(), *Locks::subtype_check_lock_);
+  if ((false) &&  // FIXME: Inliner does not respect compiler_driver->IsClassToCompile()
+                  // and we're hitting an unassigned bitstring in dex2oat_image_test. b/26687569
+      kIsDebugBuild &&
+      codegen->GetCompilerOptions().IsBootImage() &&
+      codegen->GetCompilerOptions().IsForceDeterminism()) {
+    SubtypeCheckInfo::State old_state = SubtypeCheck<ObjPtr<mirror::Class>>::GetState(klass);
+    CHECK(old_state == SubtypeCheckInfo::kAssigned || old_state == SubtypeCheckInfo::kOverflowed)
+        << klass->PrettyDescriptor() << "/" << old_state
+        << " in " << codegen->GetGraph()->PrettyMethod();
+  }
+  SubtypeCheckInfo::State state = SubtypeCheck<ObjPtr<mirror::Class>>::EnsureAssigned(klass);
+  return state == SubtypeCheckInfo::kAssigned;
+}
+
+TypeCheckKind HSharpening::ComputeTypeCheckKind(ObjPtr<mirror::Class> klass,
+                                                CodeGenerator* codegen,
+                                                CompilerDriver* compiler_driver,
+                                                bool needs_access_check) {
+  if (klass == nullptr) {
+    return TypeCheckKind::kUnresolvedCheck;
+  } else if (klass->IsInterface()) {
+    return TypeCheckKind::kInterfaceCheck;
+  } else if (klass->IsArrayClass()) {
+    if (klass->GetComponentType()->IsObjectClass()) {
+      return TypeCheckKind::kArrayObjectCheck;
+    } else if (klass->CannotBeAssignedFromOtherTypes()) {
+      return TypeCheckKind::kExactCheck;
+    } else {
+      return TypeCheckKind::kArrayCheck;
+    }
+  } else if (klass->IsFinal()) {  // TODO: Consider using bitstring for final classes.
+    return TypeCheckKind::kExactCheck;
+  } else if (kBitstringSubtypeCheckEnabled &&
+             !needs_access_check &&
+             CanUseTypeCheckBitstring(klass, codegen, compiler_driver)) {
+    // TODO: We should not need the `!needs_access_check` check but getting rid of that
+    // requires rewriting some optimizations in instruction simplifier.
+    return TypeCheckKind::kBitstringCheck;
+  } else if (klass->IsAbstract()) {
+    return TypeCheckKind::kAbstractClassCheck;
+  } else {
+    return TypeCheckKind::kClassHierarchyCheck;
+  }
+}
+
 void HSharpening::ProcessLoadString(
     HLoadString* load_string,
     CodeGenerator* codegen,