1 files changed, 330 insertions, 0 deletions
diff --git a/runtime/indirect_reference_table.cc b/runtime/indirect_reference_table.cc
new file mode 100644
index 0000000..0287d74
--- /dev/null
+++ b/runtime/indirect_reference_table.cc
@@ -0,0 +1,330 @@
+/*
+ * Copyright (C) 2009 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 "indirect_reference_table.h"
+#include "jni_internal.h"
+#include "reference_table.h"
+#include "runtime.h"
+#include "scoped_thread_state_change.h"
+#include "thread.h"
+#include "utils.h"
+
+#include <cstdlib>
+
+namespace art {
+
+static void AbortMaybe() {
+  // If -Xcheck:jni is on, it'll give a more detailed error before aborting.
+  if (!Runtime::Current()->GetJavaVM()->check_jni) {
+    // Otherwise, we want to abort rather than hand back a bad reference.
+    LOG(FATAL) << "JNI ERROR (app bug): see above.";
+  }
+}
+
+IndirectReferenceTable::IndirectReferenceTable(size_t initialCount,
+                                               size_t maxCount, IndirectRefKind desiredKind) {
+  CHECK_GT(initialCount, 0U);
+  CHECK_LE(initialCount, maxCount);
+  CHECK_NE(desiredKind, kSirtOrInvalid);
+
+  table_ = reinterpret_cast<const mirror::Object**>(malloc(initialCount * sizeof(const mirror::Object*)));
+  CHECK(table_ != NULL);
+  memset(table_, 0xd1, initialCount * sizeof(const mirror::Object*));
+
+  slot_data_ = reinterpret_cast<IndirectRefSlot*>(calloc(initialCount, sizeof(IndirectRefSlot)));
+  CHECK(slot_data_ != NULL);
+
+  segment_state_.all = IRT_FIRST_SEGMENT;
+  alloc_entries_ = initialCount;
+  max_entries_ = maxCount;
+  kind_ = desiredKind;
+}
+
+IndirectReferenceTable::~IndirectReferenceTable() {
+  free(table_);
+  free(slot_data_);
+  table_ = NULL;
+  slot_data_ = NULL;
+  alloc_entries_ = max_entries_ = -1;
+}
+
+// Make sure that the entry at "idx" is correctly paired with "iref".
+bool IndirectReferenceTable::CheckEntry(const char* what, IndirectRef iref, int idx) const {
+  const mirror::Object* obj = table_[idx];
+  IndirectRef checkRef = ToIndirectRef(obj, idx);
+  if (UNLIKELY(checkRef != iref)) {
+    LOG(ERROR) << "JNI ERROR (app bug): attempt to " << what
+               << " stale " << kind_ << " " << iref
+               << " (should be " << checkRef << ")";
+    AbortMaybe();
+    return false;
+  }
+  return true;
+}
+
+IndirectRef IndirectReferenceTable::Add(uint32_t cookie, const mirror::Object* obj) {
+  IRTSegmentState prevState;
+  prevState.all = cookie;
+  size_t topIndex = segment_state_.parts.topIndex;
+
+  DCHECK(obj != NULL);
+  // TODO: stronger sanity check on the object (such as in heap)
+  DCHECK_ALIGNED(reinterpret_cast<uintptr_t>(obj), 8);
+  DCHECK(table_ != NULL);
+  DCHECK_LE(alloc_entries_, max_entries_);
+  DCHECK_GE(segment_state_.parts.numHoles, prevState.parts.numHoles);
+
+  if (topIndex == alloc_entries_) {
+    // reached end of allocated space; did we hit buffer max?
+    if (topIndex == max_entries_) {
+      LOG(FATAL) << "JNI ERROR (app bug): " << kind_ << " table overflow "
+                 << "(max=" << max_entries_ << ")\n"
+                 << MutatorLockedDumpable<IndirectReferenceTable>(*this);
+    }
+
+    size_t newSize = alloc_entries_ * 2;
+    if (newSize > max_entries_) {
+      newSize = max_entries_;
+    }
+    DCHECK_GT(newSize, alloc_entries_);
+
+    table_ = reinterpret_cast<const mirror::Object**>(realloc(table_, newSize * sizeof(const mirror::Object*)));
+    slot_data_ = reinterpret_cast<IndirectRefSlot*>(realloc(slot_data_,
+                                                            newSize * sizeof(IndirectRefSlot)));
+    if (table_ == NULL || slot_data_ == NULL) {
+      LOG(FATAL) << "JNI ERROR (app bug): unable to expand "
+                 << kind_ << " table (from "
+                 << alloc_entries_ << " to " << newSize
+                 << ", max=" << max_entries_ << ")\n"
+                 << MutatorLockedDumpable<IndirectReferenceTable>(*this);
+    }
+
+    // Clear the newly-allocated slot_data_ elements.
+    memset(slot_data_ + alloc_entries_, 0, (newSize - alloc_entries_) * sizeof(IndirectRefSlot));
+
+    alloc_entries_ = newSize;
+  }
+
+  // We know there's enough room in the table.  Now we just need to find
+  // the right spot.  If there's a hole, find it and fill it; otherwise,
+  // add to the end of the list.
+  IndirectRef result;
+  int numHoles = segment_state_.parts.numHoles - prevState.parts.numHoles;
+  if (numHoles > 0) {
+    DCHECK_GT(topIndex, 1U);
+    // Find the first hole; likely to be near the end of the list.
+    const mirror::Object** pScan = &table_[topIndex - 1];
+    DCHECK(*pScan != NULL);
+    while (*--pScan != NULL) {
+      DCHECK_GE(pScan, table_ + prevState.parts.topIndex);
+    }
+    UpdateSlotAdd(obj, pScan - table_);
+    result = ToIndirectRef(obj, pScan - table_);
+    *pScan = obj;
+    segment_state_.parts.numHoles--;
+  } else {
+    // Add to the end.
+    UpdateSlotAdd(obj, topIndex);
+    result = ToIndirectRef(obj, topIndex);
+    table_[topIndex++] = obj;
+    segment_state_.parts.topIndex = topIndex;
+  }
+  if (false) {
+    LOG(INFO) << "+++ added at " << ExtractIndex(result) << " top=" << segment_state_.parts.topIndex
+              << " holes=" << segment_state_.parts.numHoles;
+  }
+
+  DCHECK(result != NULL);
+  return result;
+}
+
+void IndirectReferenceTable::AssertEmpty() {
+  if (UNLIKELY(begin() != end())) {
+    ScopedObjectAccess soa(Thread::Current());
+    LOG(FATAL) << "Internal Error: non-empty local reference table\n"
+               << MutatorLockedDumpable<IndirectReferenceTable>(*this);
+  }
+}
+
+// Verifies that the indirect table lookup is valid.
+// Returns "false" if something looks bad.
+bool IndirectReferenceTable::GetChecked(IndirectRef iref) const {
+  if (UNLIKELY(iref == NULL)) {
+    LOG(WARNING) << "Attempt to look up NULL " << kind_;
+    return false;
+  }
+  if (UNLIKELY(GetIndirectRefKind(iref) == kSirtOrInvalid)) {
+    LOG(ERROR) << "JNI ERROR (app bug): invalid " << kind_ << " " << iref;
+    AbortMaybe();
+    return false;
+  }
+
+  int topIndex = segment_state_.parts.topIndex;
+  int idx = ExtractIndex(iref);
+  if (UNLIKELY(idx >= topIndex)) {
+    LOG(ERROR) << "JNI ERROR (app bug): accessed stale " << kind_ << " "
+               << iref << " (index " << idx << " in a table of size " << topIndex << ")";
+    AbortMaybe();
+    return false;
+  }
+
+  if (UNLIKELY(table_[idx] == NULL)) {
+    LOG(ERROR) << "JNI ERROR (app bug): accessed deleted " << kind_ << " " << iref;
+    AbortMaybe();
+    return false;
+  }
+
+  if (UNLIKELY(!CheckEntry("use", iref, idx))) {
+    return false;
+  }
+
+  return true;
+}
+
+static int Find(mirror::Object* direct_pointer, int bottomIndex, int topIndex, const mirror::Object** table) {
+  for (int i = bottomIndex; i < topIndex; ++i) {
+    if (table[i] == direct_pointer) {
+      return i;
+    }
+  }
+  return -1;
+}
+
+bool IndirectReferenceTable::ContainsDirectPointer(mirror::Object* direct_pointer) const {
+  return Find(direct_pointer, 0, segment_state_.parts.topIndex, table_) != -1;
+}
+
+// Removes an object. We extract the table offset bits from "iref"
+// and zap the corresponding entry, leaving a hole if it's not at the top.
+// If the entry is not between the current top index and the bottom index
+// specified by the cookie, we don't remove anything. This is the behavior
+// required by JNI's DeleteLocalRef function.
+// This method is not called when a local frame is popped; this is only used
+// for explicit single removals.
+// Returns "false" if nothing was removed.
+bool IndirectReferenceTable::Remove(uint32_t cookie, IndirectRef iref) {
+  IRTSegmentState prevState;
+  prevState.all = cookie;
+  int topIndex = segment_state_.parts.topIndex;
+  int bottomIndex = prevState.parts.topIndex;
+
+  DCHECK(table_ != NULL);
+  DCHECK_LE(alloc_entries_, max_entries_);
+  DCHECK_GE(segment_state_.parts.numHoles, prevState.parts.numHoles);
+
+  int idx = ExtractIndex(iref);
+
+  JavaVMExt* vm = Runtime::Current()->GetJavaVM();
+  if (GetIndirectRefKind(iref) == kSirtOrInvalid &&
+      Thread::Current()->SirtContains(reinterpret_cast<jobject>(iref))) {
+    LOG(WARNING) << "Attempt to remove local SIRT entry from IRT, ignoring";
+    return true;
+  }
+  if (GetIndirectRefKind(iref) == kSirtOrInvalid && vm->work_around_app_jni_bugs) {
+    mirror::Object* direct_pointer = reinterpret_cast<mirror::Object*>(iref);
+    idx = Find(direct_pointer, bottomIndex, topIndex, table_);
+    if (idx == -1) {
+      LOG(WARNING) << "trying to work around app JNI bugs, but didn't find " << iref << " in table!";
+      return false;
+    }
+  }
+
+  if (idx < bottomIndex) {
+    // Wrong segment.
+    LOG(WARNING) << "Attempt to remove index outside index area (" << idx
+                 << " vs " << bottomIndex << "-" << topIndex << ")";
+    return false;
+  }
+  if (idx >= topIndex) {
+    // Bad --- stale reference?
+    LOG(WARNING) << "Attempt to remove invalid index " << idx
+                 << " (bottom=" << bottomIndex << " top=" << topIndex << ")";
+    return false;
+  }
+
+  if (idx == topIndex-1) {
+    // Top-most entry.  Scan up and consume holes.
+
+    if (!vm->work_around_app_jni_bugs && !CheckEntry("remove", iref, idx)) {
+      return false;
+    }
+
+    table_[idx] = NULL;
+    int numHoles = segment_state_.parts.numHoles - prevState.parts.numHoles;
+    if (numHoles != 0) {
+      while (--topIndex > bottomIndex && numHoles != 0) {
+        if (false) {
+          LOG(INFO) << "+++ checking for hole at " << topIndex-1
+                    << " (cookie=" << cookie << ") val=" << table_[topIndex - 1];
+        }
+        if (table_[topIndex-1] != NULL) {
+          break;
+        }
+        if (false) {
+          LOG(INFO) << "+++ ate hole at " << (topIndex - 1);
+        }
+        numHoles--;
+      }
+      segment_state_.parts.numHoles = numHoles + prevState.parts.numHoles;
+      segment_state_.parts.topIndex = topIndex;
+    } else {
+      segment_state_.parts.topIndex = topIndex-1;
+      if (false) {
+        LOG(INFO) << "+++ ate last entry " << topIndex - 1;
+      }
+    }
+  } else {
+    // Not the top-most entry.  This creates a hole.  We NULL out the
+    // entry to prevent somebody from deleting it twice and screwing up
+    // the hole count.
+    if (table_[idx] == NULL) {
+      LOG(INFO) << "--- WEIRD: removing null entry " << idx;
+      return false;
+    }
+    if (!vm->work_around_app_jni_bugs && !CheckEntry("remove", iref, idx)) {
+      return false;
+    }
+
+    table_[idx] = NULL;
+    segment_state_.parts.numHoles++;
+    if (false) {
+      LOG(INFO) << "+++ left hole at " << idx << ", holes=" << segment_state_.parts.numHoles;
+    }
+  }
+
+  return true;
+}
+
+void IndirectReferenceTable::VisitRoots(RootVisitor* visitor, void* arg) {
+  typedef IndirectReferenceTable::iterator It; // TODO: C++0x auto
+  for (It it = begin(), end = this->end(); it != end; ++it) {
+    visitor(**it, arg);
+  }
+}
+
+void IndirectReferenceTable::Dump(std::ostream& os) const {
+  os << kind_ << " table dump:\n";
+  std::vector<const mirror::Object*> entries(table_, table_ + Capacity());
+  // Remove NULLs.
+  for (int i = entries.size() - 1; i >= 0; --i) {
+    if (entries[i] == NULL) {
+      entries.erase(entries.begin() + i);
+    }
+  }
+  ReferenceTable::Dump(os, entries);
+}
+
+}  // namespace art