Implement Integer.valueOf() intrinsic for PIC.
And fix the intrinsic for JIT even in case when someone
messes up the IntegerCache using reflection. Two cases are
exposed with a regression test (one that previously failed
randomly and one that failed 100%) but other crashes were
possible; for example, we would need a read barrier for
array reads when elements are not guaranteed to be in the
boot image.
The new approach loads references only from the boot image
live objects array which cannot be touched by reflection.
The referenced objects and IntegerCache.cache are exposed
and can lead to weird behavior but not crashes.
On x86, the pc_relative_fixups_86 actually checks the cache
an additional time but discrepancies between this check and
the location building at the beginning of codegen should be
OK as the HIsX86ComputeBaseMethodAddress should be added
for PIC regardless of whether pc_relative_fixups_86 thinks
the method is intrinsified or not.
Test: 717-integer-value-of
Test: Pixel 2 XL boots.
Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing --pictest --npictest
Test: testrunner.py --host --jit
Test: testrunner.py --target --optimizing --pictest --npictest
Test: testrunner.py --target --jit
Bug: 71526895
Change-Id: I89b3245a62aba22980c86a99e2af480bfa250af1
diff --git a/compiler/optimizing/intrinsic_objects.cc b/compiler/optimizing/intrinsic_objects.cc
new file mode 100644
index 0000000..3c20ad6
--- /dev/null
+++ b/compiler/optimizing/intrinsic_objects.cc
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "intrinsic_objects.h"
+
+#include "art_field-inl.h"
+#include "base/logging.h"
+#include "class_root.h"
+#include "handle.h"
+#include "obj_ptr-inl.h"
+#include "mirror/object_array-inl.h"
+
+namespace art {
+
+static ObjPtr<mirror::ObjectArray<mirror::Object>> LookupIntegerCache(Thread* self,
+ ClassLinker* class_linker)
+ REQUIRES_SHARED(Locks::mutator_lock_) {
+ ObjPtr<mirror::Class> integer_cache_class = class_linker->LookupClass(
+ self, "Ljava/lang/Integer$IntegerCache;", /* class_linker */ nullptr);
+ if (integer_cache_class == nullptr || !integer_cache_class->IsInitialized()) {
+ return nullptr;
+ }
+ ArtField* cache_field =
+ integer_cache_class->FindDeclaredStaticField("cache", "[Ljava/lang/Integer;");
+ CHECK(cache_field != nullptr);
+ ObjPtr<mirror::ObjectArray<mirror::Object>> integer_cache =
+ ObjPtr<mirror::ObjectArray<mirror::Object>>::DownCast(
+ cache_field->GetObject(integer_cache_class));
+ CHECK(integer_cache != nullptr);
+ return integer_cache;
+}
+
+ObjPtr<mirror::ObjectArray<mirror::Object>> IntrinsicObjects::AllocateBootImageLiveObjects(
+ Thread* self,
+ ClassLinker* class_linker) REQUIRES_SHARED(Locks::mutator_lock_) {
+ // The objects used for the Integer.valueOf() intrinsic must remain live even if references
+ // to them are removed using reflection. Image roots are not accessible through reflection,
+ // so the array we construct here shall keep them alive.
+ StackHandleScope<1> hs(self);
+ Handle<mirror::ObjectArray<mirror::Object>> integer_cache =
+ hs.NewHandle(LookupIntegerCache(self, class_linker));
+ size_t live_objects_size =
+ (integer_cache != nullptr) ? (/* cache */ 1u + integer_cache->GetLength()) : 0u;
+ ObjPtr<mirror::ObjectArray<mirror::Object>> live_objects =
+ mirror::ObjectArray<mirror::Object>::Alloc(
+ self, GetClassRoot<mirror::ObjectArray<mirror::Object>>(class_linker), live_objects_size);
+ int32_t index = 0;
+ if (integer_cache != nullptr) {
+ live_objects->Set(index++, integer_cache.Get());
+ for (int32_t i = 0, length = integer_cache->GetLength(); i != length; ++i) {
+ live_objects->Set(index++, integer_cache->Get(i));
+ }
+ }
+ CHECK_EQ(index, live_objects->GetLength());
+
+ if (kIsDebugBuild && integer_cache != nullptr) {
+ CHECK_EQ(integer_cache.Get(), GetIntegerValueOfCache(live_objects));
+ for (int32_t i = 0, len = integer_cache->GetLength(); i != len; ++i) {
+ CHECK_EQ(integer_cache->GetWithoutChecks(i), GetIntegerValueOfObject(live_objects, i));
+ }
+ }
+ return live_objects;
+}
+
+ObjPtr<mirror::ObjectArray<mirror::Object>> IntrinsicObjects::GetIntegerValueOfCache(
+ ObjPtr<mirror::ObjectArray<mirror::Object>> boot_image_live_objects) {
+ DCHECK(boot_image_live_objects != nullptr);
+ if (boot_image_live_objects->GetLength() == 0u) {
+ return nullptr; // No intrinsic objects.
+ }
+ // No need for read barrier for boot image object or for verifying the value that was just stored.
+ ObjPtr<mirror::Object> result =
+ boot_image_live_objects->GetWithoutChecks<kVerifyNone, kWithoutReadBarrier>(0);
+ DCHECK(result != nullptr);
+ DCHECK(result->IsObjectArray());
+ DCHECK(result->GetClass()->DescriptorEquals("[Ljava/lang/Integer;"));
+ return ObjPtr<mirror::ObjectArray<mirror::Object>>::DownCast(result);
+}
+
+ObjPtr<mirror::Object> IntrinsicObjects::GetIntegerValueOfObject(
+ ObjPtr<mirror::ObjectArray<mirror::Object>> boot_image_live_objects,
+ uint32_t index) {
+ DCHECK(boot_image_live_objects != nullptr);
+ DCHECK_NE(boot_image_live_objects->GetLength(), 0);
+ DCHECK_LT(index,
+ static_cast<uint32_t>(GetIntegerValueOfCache(boot_image_live_objects)->GetLength()));
+
+ // No need for read barrier for boot image object or for verifying the value that was just stored.
+ ObjPtr<mirror::Object> result =
+ boot_image_live_objects->GetWithoutChecks<kVerifyNone, kWithoutReadBarrier>(
+ /* skip the IntegerCache.cache */ 1u + index);
+ DCHECK(result != nullptr);
+ DCHECK(result->GetClass()->DescriptorEquals("Ljava/lang/Integer;"));
+ return result;
+}
+
+MemberOffset IntrinsicObjects::GetIntegerValueOfArrayDataOffset(
+ ObjPtr<mirror::ObjectArray<mirror::Object>> boot_image_live_objects) {
+ DCHECK_NE(boot_image_live_objects->GetLength(), 0);
+ MemberOffset result = mirror::ObjectArray<mirror::Object>::OffsetOfElement(1u);
+ DCHECK_EQ(GetIntegerValueOfObject(boot_image_live_objects, 0u),
+ (boot_image_live_objects
+ ->GetFieldObject<mirror::Object, kVerifyNone, kWithoutReadBarrier>(result)));
+ return result;
+}
+
+} // namespace art