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/*
* 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_RUNTIME_VERIFIER_DEX_GC_MAP_H_
#define ART_RUNTIME_VERIFIER_DEX_GC_MAP_H_
#include <stdint.h>
#include "base/logging.h"
#include "base/macros.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:
explicit DexPcToReferenceMap(const uint8_t* data) : data_(data) {
CHECK(data_ != nullptr);
}
// The total size of the reference bit map including header.
size_t RawSize() const {
return EntryWidth() * NumEntries() + 4u /* header */;
}
// 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_;
}
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_RUNTIME_VERIFIER_DEX_GC_MAP_H_
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