From 21d5994583c679cd5d8573b5d35dbd659bdca2c7 Mon Sep 17 00:00:00 2001
From: Alex Light <allight@google.com>
Date: Wed, 19 Jun 2019 12:58:22 -0700
Subject: Support using opaque JNI ids

Currently JNI ids (jmethodID &  jfieldID) are created by simply
casting the corresponding ART structure pointer. This is great for
simplicity but means we are prevented from performing operations that
could change these pointer values. To support these use-cases add
support for loading the runtime with a layer of indirection between
these ids and the internal art data types.

Currently the JNI id type can be toggled only by passing the new
'-Xopaque-jni-ids:{true,false}' flag during startup.

This changes the --debuggable test configuration to pass
'-Xopaque-jni-ids:true' in order to get test coverage of this feature
using the 'art-jit' configuration.

Test: ./test.py --host --debuggable
Test: ./test.py --host --debuggable --jit-on-first-use
Test: ./test/testrunnner/run_build_test_target.py art-jit
Bug: 134162467
Change-Id: Id8c8cb9a5b8ff18dc2f40892fae2d344a7214f44
---
 runtime/mirror/class_ext-inl.h | 69 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

(limited to 'runtime/mirror/class_ext-inl.h')

diff --git a/runtime/mirror/class_ext-inl.h b/runtime/mirror/class_ext-inl.h
index bf51654447..ead02eed3b 100644
--- a/runtime/mirror/class_ext-inl.h
+++ b/runtime/mirror/class_ext-inl.h
@@ -19,12 +19,81 @@
 
 #include "class_ext.h"
 
+#include "array-inl.h"
 #include "art_method-inl.h"
+#include "handle_scope.h"
 #include "object-inl.h"
 
 namespace art {
 namespace mirror {
 
+template <VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
+inline ObjPtr<PointerArray> ClassExt::EnsureJniIdsArrayPresent(MemberOffset off, size_t count) {
+  ObjPtr<PointerArray> existing(
+      GetFieldObject<PointerArray, kVerifyFlags, kReadBarrierOption>(off));
+  if (!existing.IsNull()) {
+    return existing;
+  }
+  Thread* self = Thread::Current();
+  StackHandleScope<2> hs(self);
+  Handle<ClassExt> h_this(hs.NewHandle(this));
+  Handle<PointerArray> new_arr(
+      hs.NewHandle(Runtime::Current()->GetClassLinker()->AllocPointerArray(self, count)));
+  if (new_arr.IsNull()) {
+    // Fail.
+    self->AssertPendingOOMException();
+    return nullptr;
+  }
+  bool set;
+  // Set the ext_data_ field using CAS semantics.
+  if (Runtime::Current()->IsActiveTransaction()) {
+    set = h_this->CasFieldObject<true>(
+        off, nullptr, new_arr.Get(), CASMode::kStrong, std::memory_order_seq_cst);
+  } else {
+    set = h_this->CasFieldObject<false>(
+        off, nullptr, new_arr.Get(), CASMode::kStrong, std::memory_order_seq_cst);
+  }
+  ObjPtr<PointerArray> ret(
+      set ? new_arr.Get()
+          : h_this->GetFieldObject<PointerArray, kVerifyFlags, kReadBarrierOption>(off));
+  CHECK(!ret.IsNull());
+  return ret;
+}
+
+template <VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
+inline ObjPtr<PointerArray> ClassExt::EnsureJMethodIDsArrayPresent(size_t count) {
+  return EnsureJniIdsArrayPresent<kVerifyFlags, kReadBarrierOption>(
+      MemberOffset(OFFSET_OF_OBJECT_MEMBER(ClassExt, jmethod_ids_)), count);
+}
+template <VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
+inline ObjPtr<PointerArray> ClassExt::EnsureStaticJFieldIDsArrayPresent(size_t count) {
+  return EnsureJniIdsArrayPresent<kVerifyFlags, kReadBarrierOption>(
+      MemberOffset(OFFSET_OF_OBJECT_MEMBER(ClassExt, static_jfield_ids_)), count);
+}
+template <VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
+inline ObjPtr<PointerArray> ClassExt::EnsureInstanceJFieldIDsArrayPresent(size_t count) {
+  return EnsureJniIdsArrayPresent<kVerifyFlags, kReadBarrierOption>(
+      MemberOffset(OFFSET_OF_OBJECT_MEMBER(ClassExt, instance_jfield_ids_)), count);
+}
+
+template <VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
+inline ObjPtr<PointerArray> ClassExt::GetInstanceJFieldIDs() {
+  return GetFieldObject<PointerArray, kVerifyFlags, kReadBarrierOption>(
+      OFFSET_OF_OBJECT_MEMBER(ClassExt, instance_jfield_ids_));
+}
+
+template <VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
+inline ObjPtr<PointerArray> ClassExt::GetStaticJFieldIDs() {
+  return GetFieldObject<PointerArray, kVerifyFlags, kReadBarrierOption>(
+      OFFSET_OF_OBJECT_MEMBER(ClassExt, static_jfield_ids_));
+}
+
+template <VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
+inline ObjPtr<PointerArray> ClassExt::GetJMethodIDs() {
+  return GetFieldObject<PointerArray, kVerifyFlags, kReadBarrierOption>(
+      OFFSET_OF_OBJECT_MEMBER(ClassExt, jmethod_ids_));
+}
+
 inline ObjPtr<Object> ClassExt::GetVerifyError() {
   return GetFieldObject<ClassExt>(OFFSET_OF_OBJECT_MEMBER(ClassExt, verify_error_));
 }
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