NativePcOffsetToReferenceMap
Rather than translate a native PC to a Dex PC and then to the reference
bitmap, just go straight from the native PC to the reference bitmap.
Encode the native PC offsets using a hash rather than linearly
searching.
Change-Id: Iee1073d93c941c0a31f639e5f23cea9e9f747bee
diff --git a/src/verifier/dex_gc_map.h b/src/verifier/dex_gc_map.h
new file mode 100644
index 0000000..d588cfd
--- /dev/null
+++ b/src/verifier/dex_gc_map.h
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#ifndef ART_SRC_VERIFIER_DEX_GC_MAP_H_
+#define ART_SRC_VERIFIER_DEX_GC_MAP_H_
+
+#include "logging.h"
+#include "macros.h"
+#include <stdint.h>
+
+namespace art {
+namespace verifier {
+
+/*
+ * Format enumeration for RegisterMap data area.
+ */
+enum RegisterMapFormat {
+ kRegMapFormatUnknown = 0,
+ kRegMapFormatNone = 1, // Indicates no map data follows.
+ kRegMapFormatCompact8 = 2, // Compact layout, 8-bit addresses.
+ kRegMapFormatCompact16 = 3, // Compact layout, 16-bit addresses.
+};
+
+// Lightweight wrapper for Dex PC to reference bit maps.
+class DexPcToReferenceMap {
+ public:
+ DexPcToReferenceMap(const uint8_t* data, size_t data_length) : data_(data) {
+ CHECK(data_ != NULL);
+ // Check the size of the table agrees with the number of entries
+ size_t data_size = data_length - 4;
+ DCHECK_EQ(EntryWidth() * NumEntries(), data_size);
+ }
+
+ // The number of entries in the table
+ size_t NumEntries() const {
+ return GetData()[2] | (GetData()[3] << 8);
+ }
+
+ // Get the Dex PC at the given index
+ uint16_t GetDexPc(size_t index) const {
+ size_t entry_offset = index * EntryWidth();
+ if (DexPcWidth() == 1) {
+ return Table()[entry_offset];
+ } else {
+ return Table()[entry_offset] | (Table()[entry_offset + 1] << 8);
+ }
+ }
+
+ // Return address of bitmap encoding what are live references
+ const uint8_t* GetBitMap(size_t index) const {
+ size_t entry_offset = index * EntryWidth();
+ return &Table()[entry_offset + DexPcWidth()];
+ }
+
+ // Find the bitmap associated with the given dex pc
+ const uint8_t* FindBitMap(uint16_t dex_pc, bool error_if_not_present = true) const;
+
+ // The number of bytes used to encode registers
+ size_t RegWidth() const {
+ return GetData()[1] | ((GetData()[0] & ~kRegMapFormatMask) << kRegMapFormatShift);
+ }
+
+ private:
+ // Table of num_entries * (dex pc, bitmap)
+ const uint8_t* Table() const {
+ return GetData() + 4;
+ }
+
+ // The format of the table of the PCs for the table
+ RegisterMapFormat Format() const {
+ return static_cast<RegisterMapFormat>(GetData()[0] & kRegMapFormatMask);
+ }
+
+ // Number of bytes used to encode a dex pc
+ size_t DexPcWidth() const {
+ RegisterMapFormat format = Format();
+ switch (format) {
+ case kRegMapFormatCompact8:
+ return 1;
+ case kRegMapFormatCompact16:
+ return 2;
+ default:
+ LOG(FATAL) << "Invalid format " << static_cast<int>(format);
+ return -1;
+ }
+ }
+
+ // The width of an entry in the table
+ size_t EntryWidth() const {
+ return DexPcWidth() + RegWidth();
+ }
+
+ const uint8_t* GetData() const {
+ return data_;
+ }
+
+ friend class MethodVerifier;
+
+ static const int kRegMapFormatShift = 5;
+ static const uint8_t kRegMapFormatMask = 0x7;
+
+ const uint8_t* const data_; // The header and table data
+};
+
+} // namespace verifier
+} // namespace art
+
+#endif // ART_SRC_VERIFIER_DEX_GC_MAP_H_