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review.blissroms.org / platform_art / 93aa03c91328dca71fb5674d040e76d95204ccff / . / runtime / stack_map.h
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/*
* Copyright (C) 2014 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_STACK_MAP_H_
#define ART_RUNTIME_STACK_MAP_H_
#include "base/bit_vector.h"
#include "base/bit_utils.h"
#include "dex_file.h"
#include "memory_region.h"
#include "leb128.h"
namespace art {
class VariableIndentationOutputStream;
// Size of a frame slot, in bytes. This constant is a signed value,
// to please the compiler in arithmetic operations involving int32_t
// (signed) values.
static constexpr ssize_t kFrameSlotSize = 4;
// Size of Dex virtual registers.
static constexpr size_t kVRegSize = 4;
class CodeInfo;
class StackMapEncoding;
struct CodeInfoEncoding;
/**
* Classes in the following file are wrapper on stack map information backed
* by a MemoryRegion. As such they read and write to the region, they don't have
* their own fields.
*/
// Dex register location container used by DexRegisterMap and StackMapStream.
class DexRegisterLocation {
public:
/*
* The location kind used to populate the Dex register information in a
* StackMapStream can either be:
* - kStack: vreg stored on the stack, value holds the stack offset;
* - kInRegister: vreg stored in low 32 bits of a core physical register,
* value holds the register number;
* - kInRegisterHigh: vreg stored in high 32 bits of a core physical register,
* value holds the register number;
* - kInFpuRegister: vreg stored in low 32 bits of an FPU register,
* value holds the register number;
* - kInFpuRegisterHigh: vreg stored in high 32 bits of an FPU register,
* value holds the register number;
* - kConstant: value holds the constant;
*
* In addition, DexRegisterMap also uses these values:
* - kInStackLargeOffset: value holds a "large" stack offset (greater than
* or equal to 128 bytes);
* - kConstantLargeValue: value holds a "large" constant (lower than 0, or
* or greater than or equal to 32);
* - kNone: the register has no location, meaning it has not been set.
*/
enum class Kind : uint8_t {
// Short location kinds, for entries fitting on one byte (3 bits
// for the kind, 5 bits for the value) in a DexRegisterMap.
kInStack = 0, // 0b000
kInRegister = 1, // 0b001
kInRegisterHigh = 2, // 0b010
kInFpuRegister = 3, // 0b011
kInFpuRegisterHigh = 4, // 0b100
kConstant = 5, // 0b101
// Large location kinds, requiring a 5-byte encoding (1 byte for the
// kind, 4 bytes for the value).
// Stack location at a large offset, meaning that the offset value
// divided by the stack frame slot size (4 bytes) cannot fit on a
// 5-bit unsigned integer (i.e., this offset value is greater than
// or equal to 2^5 * 4 = 128 bytes).
kInStackLargeOffset = 6, // 0b110
// Large constant, that cannot fit on a 5-bit signed integer (i.e.,
// lower than 0, or greater than or equal to 2^5 = 32).
kConstantLargeValue = 7, // 0b111
// Entries with no location are not stored and do not need own marker.
kNone = static_cast<uint8_t>(-1),
kLastLocationKind = kConstantLargeValue
};
static_assert(
sizeof(Kind) == 1u,
"art::DexRegisterLocation::Kind has a size different from one byte.");
static bool IsShortLocationKind(Kind kind) {
switch (kind) {
case Kind::kInStack:
case Kind::kInRegister:
case Kind::kInRegisterHigh:
case Kind::kInFpuRegister:
case Kind::kInFpuRegisterHigh:
case Kind::kConstant:
return true;
case Kind::kInStackLargeOffset:
case Kind::kConstantLargeValue:
return false;
case Kind::kNone:
LOG(FATAL) << "Unexpected location kind";
}
UNREACHABLE();
}
// Convert `kind` to a "surface" kind, i.e. one that doesn't include
// any value with a "large" qualifier.
// TODO: Introduce another enum type for the surface kind?
static Kind ConvertToSurfaceKind(Kind kind) {
switch (kind) {
case Kind::kInStack:
case Kind::kInRegister:
case Kind::kInRegisterHigh:
case Kind::kInFpuRegister:
case Kind::kInFpuRegisterHigh:
case Kind::kConstant:
return kind;
case Kind::kInStackLargeOffset:
return Kind::kInStack;
case Kind::kConstantLargeValue:
return Kind::kConstant;
case Kind::kNone:
return kind;
}
UNREACHABLE();
}
// Required by art::StackMapStream::LocationCatalogEntriesIndices.
DexRegisterLocation() : kind_(Kind::kNone), value_(0) {}
DexRegisterLocation(Kind kind, int32_t value) : kind_(kind), value_(value) {}
static DexRegisterLocation None() {
return DexRegisterLocation(Kind::kNone, 0);
}
// Get the "surface" kind of the location, i.e., the one that doesn't
// include any value with a "large" qualifier.
Kind GetKind() const {
return ConvertToSurfaceKind(kind_);
}
// Get the value of the location.
int32_t GetValue() const { return value_; }
// Get the actual kind of the location.
Kind GetInternalKind() const { return kind_; }
bool operator==(DexRegisterLocation other) const {
return kind_ == other.kind_ && value_ == other.value_;
}
bool operator!=(DexRegisterLocation other) const {
return !(*this == other);
}
private:
Kind kind_;
int32_t value_;
friend class DexRegisterLocationHashFn;
};
std::ostream& operator<<(std::ostream& stream, const DexRegisterLocation::Kind& kind);
/**
* Store information on unique Dex register locations used in a method.
* The information is of the form:
*
* [DexRegisterLocation+].
*
* DexRegisterLocations are either 1- or 5-byte wide (see art::DexRegisterLocation::Kind).
*/
class DexRegisterLocationCatalog {
public:
explicit DexRegisterLocationCatalog(MemoryRegion region) : region_(region) {}
// Short (compressed) location, fitting on one byte.
typedef uint8_t ShortLocation;
void SetRegisterInfo(size_t offset, const DexRegisterLocation& dex_register_location) {
DexRegisterLocation::Kind kind = ComputeCompressedKind(dex_register_location);
int32_t value = dex_register_location.GetValue();
if (DexRegisterLocation::IsShortLocationKind(kind)) {
// Short location. Compress the kind and the value as a single byte.
if (kind == DexRegisterLocation::Kind::kInStack) {
// Instead of storing stack offsets expressed in bytes for
// short stack locations, store slot offsets. A stack offset
// is a multiple of 4 (kFrameSlotSize). This means that by
// dividing it by 4, we can fit values from the [0, 128)
// interval in a short stack location, and not just values
// from the [0, 32) interval.
DCHECK_EQ(value % kFrameSlotSize, 0);
value /= kFrameSlotSize;
}
DCHECK(IsShortValue(value)) << value;
region_.StoreUnaligned<ShortLocation>(offset, MakeShortLocation(kind, value));
} else {
// Large location. Write the location on one byte and the value
// on 4 bytes.
DCHECK(!IsShortValue(value)) << value;
if (kind == DexRegisterLocation::Kind::kInStackLargeOffset) {
// Also divide large stack offsets by 4 for the sake of consistency.
DCHECK_EQ(value % kFrameSlotSize, 0);
value /= kFrameSlotSize;
}
// Data can be unaligned as the written Dex register locations can
// either be 1-byte or 5-byte wide. Use
// art::MemoryRegion::StoreUnaligned instead of
// art::MemoryRegion::Store to prevent unligned word accesses on ARM.
region_.StoreUnaligned<DexRegisterLocation::Kind>(offset, kind);
region_.StoreUnaligned<int32_t>(offset + sizeof(DexRegisterLocation::Kind), value);
}
}
// Find the offset of the location catalog entry number `location_catalog_entry_index`.
size_t FindLocationOffset(size_t location_catalog_entry_index) const {
size_t offset = kFixedSize;
// Skip the first `location_catalog_entry_index - 1` entries.
for (uint16_t i = 0; i < location_catalog_entry_index; ++i) {
// Read the first next byte and inspect its first 3 bits to decide
// whether it is a short or a large location.
DexRegisterLocation::Kind kind = ExtractKindAtOffset(offset);
if (DexRegisterLocation::IsShortLocationKind(kind)) {
// Short location. Skip the current byte.
offset += SingleShortEntrySize();
} else {
// Large location. Skip the 5 next bytes.
offset += SingleLargeEntrySize();
}
}
return offset;
}
// Get the internal kind of entry at `location_catalog_entry_index`.
DexRegisterLocation::Kind GetLocationInternalKind(size_t location_catalog_entry_index) const {
if (location_catalog_entry_index == kNoLocationEntryIndex) {
return DexRegisterLocation::Kind::kNone;
}
return ExtractKindAtOffset(FindLocationOffset(location_catalog_entry_index));
}
// Get the (surface) kind and value of entry at `location_catalog_entry_index`.
DexRegisterLocation GetDexRegisterLocation(size_t location_catalog_entry_index) const {
if (location_catalog_entry_index == kNoLocationEntryIndex) {
return DexRegisterLocation::None();
}
size_t offset = FindLocationOffset(location_catalog_entry_index);
// Read the first byte and inspect its first 3 bits to get the location.
ShortLocation first_byte = region_.LoadUnaligned<ShortLocation>(offset);
DexRegisterLocation::Kind kind = ExtractKindFromShortLocation(first_byte);
if (DexRegisterLocation::IsShortLocationKind(kind)) {
// Short location. Extract the value from the remaining 5 bits.
int32_t value = ExtractValueFromShortLocation(first_byte);
if (kind == DexRegisterLocation::Kind::kInStack) {
// Convert the stack slot (short) offset to a byte offset value.
value *= kFrameSlotSize;
}
return DexRegisterLocation(kind, value);
} else {
// Large location. Read the four next bytes to get the value.
int32_t value = region_.LoadUnaligned<int32_t>(offset + sizeof(DexRegisterLocation::Kind));
if (kind == DexRegisterLocation::Kind::kInStackLargeOffset) {
// Convert the stack slot (large) offset to a byte offset value.
value *= kFrameSlotSize;
}
return DexRegisterLocation(kind, value);
}
}
// Compute the compressed kind of `location`.
static DexRegisterLocation::Kind ComputeCompressedKind(const DexRegisterLocation& location) {
DexRegisterLocation::Kind kind = location.GetInternalKind();
switch (kind) {
case DexRegisterLocation::Kind::kInStack:
return IsShortStackOffsetValue(location.GetValue())
? DexRegisterLocation::Kind::kInStack
: DexRegisterLocation::Kind::kInStackLargeOffset;
case DexRegisterLocation::Kind::kInRegister:
case DexRegisterLocation::Kind::kInRegisterHigh:
DCHECK_GE(location.GetValue(), 0);
DCHECK_LT(location.GetValue(), 1 << kValueBits);
return kind;
case DexRegisterLocation::Kind::kInFpuRegister:
case DexRegisterLocation::Kind::kInFpuRegisterHigh:
DCHECK_GE(location.GetValue(), 0);
DCHECK_LT(location.GetValue(), 1 << kValueBits);
return kind;
case DexRegisterLocation::Kind::kConstant:
return IsShortConstantValue(location.GetValue())
? DexRegisterLocation::Kind::kConstant
: DexRegisterLocation::Kind::kConstantLargeValue;
case DexRegisterLocation::Kind::kConstantLargeValue:
case DexRegisterLocation::Kind::kInStackLargeOffset:
case DexRegisterLocation::Kind::kNone:
LOG(FATAL) << "Unexpected location kind " << kind;
}
UNREACHABLE();
}
// Can `location` be turned into a short location?
static bool CanBeEncodedAsShortLocation(const DexRegisterLocation& location) {
DexRegisterLocation::Kind kind = location.GetInternalKind();
switch (kind) {
case DexRegisterLocation::Kind::kInStack:
return IsShortStackOffsetValue(location.GetValue());
case DexRegisterLocation::Kind::kInRegister:
case DexRegisterLocation::Kind::kInRegisterHigh:
case DexRegisterLocation::Kind::kInFpuRegister:
case DexRegisterLocation::Kind::kInFpuRegisterHigh:
return true;
case DexRegisterLocation::Kind::kConstant:
return IsShortConstantValue(location.GetValue());
case DexRegisterLocation::Kind::kConstantLargeValue:
case DexRegisterLocation::Kind::kInStackLargeOffset:
case DexRegisterLocation::Kind::kNone:
LOG(FATAL) << "Unexpected location kind " << kind;
}
UNREACHABLE();
}
static size_t EntrySize(const DexRegisterLocation& location) {
return CanBeEncodedAsShortLocation(location) ? SingleShortEntrySize() : SingleLargeEntrySize();
}
static size_t SingleShortEntrySize() {
return sizeof(ShortLocation);
}
static size_t SingleLargeEntrySize() {
return sizeof(DexRegisterLocation::Kind) + sizeof(int32_t);
}
size_t Size() const {
return region_.size();
}
void Dump(VariableIndentationOutputStream* vios, const CodeInfo& code_info);
// Special (invalid) Dex register location catalog entry index meaning
// that there is no location for a given Dex register (i.e., it is
// mapped to a DexRegisterLocation::Kind::kNone location).
static constexpr size_t kNoLocationEntryIndex = -1;
private:
static constexpr int kFixedSize = 0;
// Width of the kind "field" in a short location, in bits.
static constexpr size_t kKindBits = 3;
// Width of the value "field" in a short location, in bits.
static constexpr size_t kValueBits = 5;
static constexpr uint8_t kKindMask = (1 << kKindBits) - 1;
static constexpr int32_t kValueMask = (1 << kValueBits) - 1;
static constexpr size_t kKindOffset = 0;
static constexpr size_t kValueOffset = kKindBits;
static bool IsShortStackOffsetValue(int32_t value) {
DCHECK_EQ(value % kFrameSlotSize, 0);
return IsShortValue(value / kFrameSlotSize);
}
static bool IsShortConstantValue(int32_t value) {
return IsShortValue(value);
}
static bool IsShortValue(int32_t value) {
return IsUint<kValueBits>(value);
}
static ShortLocation MakeShortLocation(DexRegisterLocation::Kind kind, int32_t value) {
uint8_t kind_integer_value = static_cast<uint8_t>(kind);
DCHECK(IsUint<kKindBits>(kind_integer_value)) << kind_integer_value;
DCHECK(IsShortValue(value)) << value;
return (kind_integer_value & kKindMask) << kKindOffset
| (value & kValueMask) << kValueOffset;
}
static DexRegisterLocation::Kind ExtractKindFromShortLocation(ShortLocation location) {
uint8_t kind = (location >> kKindOffset) & kKindMask;
DCHECK_LE(kind, static_cast<uint8_t>(DexRegisterLocation::Kind::kLastLocationKind));
// We do not encode kNone locations in the stack map.
DCHECK_NE(kind, static_cast<uint8_t>(DexRegisterLocation::Kind::kNone));
return static_cast<DexRegisterLocation::Kind>(kind);
}
static int32_t ExtractValueFromShortLocation(ShortLocation location) {
return (location >> kValueOffset) & kValueMask;
}
// Extract a location kind from the byte at position `offset`.
DexRegisterLocation::Kind ExtractKindAtOffset(size_t offset) const {
ShortLocation first_byte = region_.LoadUnaligned<ShortLocation>(offset);
return ExtractKindFromShortLocation(first_byte);
}
MemoryRegion region_;
friend class CodeInfo;
friend class StackMapStream;
};
/* Information on Dex register locations for a specific PC, mapping a
* stack map's Dex register to a location entry in a DexRegisterLocationCatalog.
* The information is of the form:
*
* [live_bit_mask, entries*]
*
* where entries are concatenated unsigned integer values encoded on a number
* of bits (fixed per DexRegisterMap instances of a CodeInfo object) depending
* on the number of entries in the Dex register location catalog
* (see DexRegisterMap::SingleEntrySizeInBits). The map is 1-byte aligned.
*/
class DexRegisterMap {
public:
explicit DexRegisterMap(MemoryRegion region) : region_(region) {}
DexRegisterMap() {}
bool IsValid() const { return region_.pointer() != nullptr; }
// Get the surface kind of Dex register `dex_register_number`.
DexRegisterLocation::Kind GetLocationKind(uint16_t dex_register_number,
uint16_t number_of_dex_registers,
const CodeInfo& code_info,
const CodeInfoEncoding& enc) const {
return DexRegisterLocation::ConvertToSurfaceKind(
GetLocationInternalKind(dex_register_number, number_of_dex_registers, code_info, enc));
}
// Get the internal kind of Dex register `dex_register_number`.
DexRegisterLocation::Kind GetLocationInternalKind(uint16_t dex_register_number,
uint16_t number_of_dex_registers,
const CodeInfo& code_info,
const CodeInfoEncoding& enc) const;
// Get the Dex register location `dex_register_number`.
DexRegisterLocation GetDexRegisterLocation(uint16_t dex_register_number,
uint16_t number_of_dex_registers,
const CodeInfo& code_info,
const CodeInfoEncoding& enc) const;
int32_t GetStackOffsetInBytes(uint16_t dex_register_number,
uint16_t number_of_dex_registers,
const CodeInfo& code_info,
const CodeInfoEncoding& enc) const {
DexRegisterLocation location =
GetDexRegisterLocation(dex_register_number, number_of_dex_registers, code_info, enc);
DCHECK(location.GetKind() == DexRegisterLocation::Kind::kInStack);
// GetDexRegisterLocation returns the offset in bytes.
return location.GetValue();
}
int32_t GetConstant(uint16_t dex_register_number,
uint16_t number_of_dex_registers,
const CodeInfo& code_info,
const CodeInfoEncoding& enc) const {
DexRegisterLocation location =
GetDexRegisterLocation(dex_register_number, number_of_dex_registers, code_info, enc);
DCHECK_EQ(location.GetKind(), DexRegisterLocation::Kind::kConstant);
return location.GetValue();
}
int32_t GetMachineRegister(uint16_t dex_register_number,
uint16_t number_of_dex_registers,
const CodeInfo& code_info,
const CodeInfoEncoding& enc) const {
DexRegisterLocation location =
GetDexRegisterLocation(dex_register_number, number_of_dex_registers, code_info, enc);
DCHECK(location.GetInternalKind() == DexRegisterLocation::Kind::kInRegister ||
location.GetInternalKind() == DexRegisterLocation::Kind::kInRegisterHigh ||
location.GetInternalKind() == DexRegisterLocation::Kind::kInFpuRegister ||
location.GetInternalKind() == DexRegisterLocation::Kind::kInFpuRegisterHigh)
<< location.GetInternalKind();
return location.GetValue();
}
// Get the index of the entry in the Dex register location catalog
// corresponding to `dex_register_number`.
size_t GetLocationCatalogEntryIndex(uint16_t dex_register_number,
uint16_t number_of_dex_registers,
size_t number_of_location_catalog_entries) const {
if (!IsDexRegisterLive(dex_register_number)) {
return DexRegisterLocationCatalog::kNoLocationEntryIndex;
}
if (number_of_location_catalog_entries == 1) {
// We do not allocate space for location maps in the case of a
// single-entry location catalog, as it is useless. The only valid
// entry index is 0;
return 0;
}
// The bit offset of the beginning of the map locations.
size_t map_locations_offset_in_bits =
GetLocationMappingDataOffset(number_of_dex_registers) * kBitsPerByte;
size_t index_in_dex_register_map = GetIndexInDexRegisterMap(dex_register_number);
DCHECK_LT(index_in_dex_register_map, GetNumberOfLiveDexRegisters(number_of_dex_registers));
// The bit size of an entry.
size_t map_entry_size_in_bits = SingleEntrySizeInBits(number_of_location_catalog_entries);
// The bit offset where `index_in_dex_register_map` is located.
size_t entry_offset_in_bits =
map_locations_offset_in_bits + index_in_dex_register_map * map_entry_size_in_bits;
size_t location_catalog_entry_index =
region_.LoadBits(entry_offset_in_bits, map_entry_size_in_bits);
DCHECK_LT(location_catalog_entry_index, number_of_location_catalog_entries);
return location_catalog_entry_index;
}
// Map entry at `index_in_dex_register_map` to `location_catalog_entry_index`.
void SetLocationCatalogEntryIndex(size_t index_in_dex_register_map,
size_t location_catalog_entry_index,
uint16_t number_of_dex_registers,
size_t number_of_location_catalog_entries) {
DCHECK_LT(index_in_dex_register_map, GetNumberOfLiveDexRegisters(number_of_dex_registers));
DCHECK_LT(location_catalog_entry_index, number_of_location_catalog_entries);
if (number_of_location_catalog_entries == 1) {
// We do not allocate space for location maps in the case of a
// single-entry location catalog, as it is useless.
return;
}
// The bit offset of the beginning of the map locations.
size_t map_locations_offset_in_bits =
GetLocationMappingDataOffset(number_of_dex_registers) * kBitsPerByte;
// The bit size of an entry.
size_t map_entry_size_in_bits = SingleEntrySizeInBits(number_of_location_catalog_entries);
// The bit offset where `index_in_dex_register_map` is located.
size_t entry_offset_in_bits =
map_locations_offset_in_bits + index_in_dex_register_map * map_entry_size_in_bits;
region_.StoreBits(entry_offset_in_bits, location_catalog_entry_index, map_entry_size_in_bits);
}
void SetLiveBitMask(uint16_t number_of_dex_registers,
const BitVector& live_dex_registers_mask) {
size_t live_bit_mask_offset_in_bits = GetLiveBitMaskOffset() * kBitsPerByte;
for (uint16_t i = 0; i < number_of_dex_registers; ++i) {
region_.StoreBit(live_bit_mask_offset_in_bits + i, live_dex_registers_mask.IsBitSet(i));
}
}
bool IsDexRegisterLive(uint16_t dex_register_number) const {
size_t live_bit_mask_offset_in_bits = GetLiveBitMaskOffset() * kBitsPerByte;
return region_.LoadBit(live_bit_mask_offset_in_bits + dex_register_number);
}
size_t GetNumberOfLiveDexRegisters(uint16_t number_of_dex_registers) const {
size_t number_of_live_dex_registers = 0;
for (size_t i = 0; i < number_of_dex_registers; ++i) {
if (IsDexRegisterLive(i)) {
++number_of_live_dex_registers;
}
}
return number_of_live_dex_registers;
}
static size_t GetLiveBitMaskOffset() {
return kFixedSize;
}
// Compute the size of the live register bit mask (in bytes), for a
// method having `number_of_dex_registers` Dex registers.
static size_t GetLiveBitMaskSize(uint16_t number_of_dex_registers) {
return RoundUp(number_of_dex_registers, kBitsPerByte) / kBitsPerByte;
}
static size_t GetLocationMappingDataOffset(uint16_t number_of_dex_registers) {
return GetLiveBitMaskOffset() + GetLiveBitMaskSize(number_of_dex_registers);
}
size_t GetLocationMappingDataSize(uint16_t number_of_dex_registers,
size_t number_of_location_catalog_entries) const {
size_t location_mapping_data_size_in_bits =
GetNumberOfLiveDexRegisters(number_of_dex_registers)
* SingleEntrySizeInBits(number_of_location_catalog_entries);
return RoundUp(location_mapping_data_size_in_bits, kBitsPerByte) / kBitsPerByte;
}
// Return the size of a map entry in bits. Note that if
// `number_of_location_catalog_entries` equals 1, this function returns 0,
// which is fine, as there is no need to allocate a map for a
// single-entry location catalog; the only valid location catalog entry index
// for a live register in this case is 0 and there is no need to
// store it.
static size_t SingleEntrySizeInBits(size_t number_of_location_catalog_entries) {
// Handle the case of 0, as we cannot pass 0 to art::WhichPowerOf2.
return number_of_location_catalog_entries == 0
? 0u
: WhichPowerOf2(RoundUpToPowerOfTwo(number_of_location_catalog_entries));
}
// Return the size of the DexRegisterMap object, in bytes.
size_t Size() const {
return region_.size();
}
void Dump(VariableIndentationOutputStream* vios,
const CodeInfo& code_info, uint16_t number_of_dex_registers) const;
private:
// Return the index in the Dex register map corresponding to the Dex
// register number `dex_register_number`.
size_t GetIndexInDexRegisterMap(uint16_t dex_register_number) const {
if (!IsDexRegisterLive(dex_register_number)) {
return kInvalidIndexInDexRegisterMap;
}
return GetNumberOfLiveDexRegisters(dex_register_number);
}
// Special (invalid) Dex register map entry index meaning that there
// is no index in the map for a given Dex register (i.e., it must
// have been mapped to a DexRegisterLocation::Kind::kNone location).
static constexpr size_t kInvalidIndexInDexRegisterMap = -1;
static constexpr int kFixedSize = 0;
MemoryRegion region_;
friend class CodeInfo;
friend class StackMapStream;
};
// Represents bit range of bit-packed integer field.
// We reuse the idea from ULEB128p1 to support encoding of -1 (aka 0xFFFFFFFF).
// If min_value is set to -1, we implicitly subtract one from any loaded value,
// and add one to any stored value. This is generalized to any negative values.
// In other words, min_value acts as a base and the stored value is added to it.
struct FieldEncoding {
FieldEncoding(size_t start_offset, size_t end_offset, int32_t min_value = 0)
: start_offset_(start_offset), end_offset_(end_offset), min_value_(min_value) {
DCHECK_LE(start_offset_, end_offset_);
DCHECK_LE(BitSize(), 32u);
}
ALWAYS_INLINE size_t BitSize() const { return end_offset_ - start_offset_; }
ALWAYS_INLINE int32_t Load(const MemoryRegion& region) const {
DCHECK_LE(end_offset_, region.size_in_bits());
const size_t bit_count = BitSize();
if (bit_count == 0) {
// Do not touch any memory if the range is empty.
return min_value_;
}
uint8_t* address = region.start() + start_offset_ / kBitsPerByte;
const uint32_t shift = start_offset_ & (kBitsPerByte - 1);
// Load the value (reading only the strictly needed bytes).
const uint32_t load_bit_count = shift + bit_count;
uint32_t value = *address++ >> shift;
if (load_bit_count > 8) {
value |= static_cast<uint32_t>(*address++) << (8 - shift);
if (load_bit_count > 16) {
value |= static_cast<uint32_t>(*address++) << (16 - shift);
if (load_bit_count > 24) {
value |= static_cast<uint32_t>(*address++) << (24 - shift);
if (load_bit_count > 32) {
value |= static_cast<uint32_t>(*address++) << (32 - shift);
}
}
}
}
// Clear unwanted most significant bits.
uint32_t clear_bit_count = 32 - bit_count;
value = (value << clear_bit_count) >> clear_bit_count;
return value + min_value_;
}
ALWAYS_INLINE void Store(MemoryRegion region, int32_t value) const {
region.StoreBits(start_offset_, value - min_value_, BitSize());
DCHECK_EQ(Load(region), value);
}
private:
size_t start_offset_;
size_t end_offset_;
int32_t min_value_;
};
class StackMapEncoding {
public:
StackMapEncoding() {}
// Set stack map bit layout based on given sizes.
// Returns the size of stack map in bytes.
size_t SetFromSizes(size_t native_pc_max,
size_t dex_pc_max,
size_t dex_register_map_size,
size_t inline_info_size,
size_t register_mask_max,
size_t stack_mask_bit_size) {
size_t bit_offset = 0;
DCHECK_EQ(kNativePcBitOffset, bit_offset);
bit_offset += MinimumBitsToStore(native_pc_max);
dex_pc_bit_offset_ = dchecked_integral_cast<uint8_t>(bit_offset);
bit_offset += MinimumBitsToStore(1 /* kNoDexPc */ + dex_pc_max);
// We also need +1 for kNoDexRegisterMap, but since the size is strictly
// greater than any offset we might try to encode, we already implicitly have it.
dex_register_map_bit_offset_ = dchecked_integral_cast<uint8_t>(bit_offset);
bit_offset += MinimumBitsToStore(dex_register_map_size);
// We also need +1 for kNoInlineInfo, but since the inline_info_size is strictly
// greater than the offset we might try to encode, we already implicitly have it.
// If inline_info_size is zero, we can encode only kNoInlineInfo (in zero bits).
inline_info_bit_offset_ = dchecked_integral_cast<uint8_t>(bit_offset);
if (inline_info_size != 0) {
bit_offset += MinimumBitsToStore(dex_register_map_size + inline_info_size);
}
register_mask_bit_offset_ = dchecked_integral_cast<uint8_t>(bit_offset);
bit_offset += MinimumBitsToStore(register_mask_max);
stack_mask_bit_offset_ = dchecked_integral_cast<uint8_t>(bit_offset);
bit_offset += stack_mask_bit_size;
return RoundUp(bit_offset, kBitsPerByte) / kBitsPerByte;
}
ALWAYS_INLINE FieldEncoding GetNativePcEncoding() const {
return FieldEncoding(kNativePcBitOffset, dex_pc_bit_offset_);
}
ALWAYS_INLINE FieldEncoding GetDexPcEncoding() const {
return FieldEncoding(dex_pc_bit_offset_, dex_register_map_bit_offset_, -1 /* min_value */);
}
ALWAYS_INLINE FieldEncoding GetDexRegisterMapEncoding() const {
return FieldEncoding(dex_register_map_bit_offset_, inline_info_bit_offset_, -1 /* min_value */);
}
ALWAYS_INLINE FieldEncoding GetInlineInfoEncoding() const {
return FieldEncoding(inline_info_bit_offset_, register_mask_bit_offset_, -1 /* min_value */);
}
ALWAYS_INLINE FieldEncoding GetRegisterMaskEncoding() const {
return FieldEncoding(register_mask_bit_offset_, stack_mask_bit_offset_);
}
ALWAYS_INLINE size_t GetStackMaskBitOffset() const {
// The end offset is not encoded. It is implicitly the end of stack map entry.
return stack_mask_bit_offset_;
}
void Dump(VariableIndentationOutputStream* vios) const;
private:
static constexpr size_t kNativePcBitOffset = 0;
uint8_t dex_pc_bit_offset_;
uint8_t dex_register_map_bit_offset_;
uint8_t inline_info_bit_offset_;
uint8_t register_mask_bit_offset_;
uint8_t stack_mask_bit_offset_;
};
/**
* A Stack Map holds compilation information for a specific PC necessary for:
* - Mapping it to a dex PC,
* - Knowing which stack entries are objects,
* - Knowing which registers hold objects,
* - Knowing the inlining information,
* - Knowing the values of dex registers.
*
* The information is of the form:
*
* [native_pc_offset, dex_pc, dex_register_map_offset, inlining_info_offset, register_mask,
* stack_mask].
*/
class StackMap {
public:
StackMap() {}
explicit StackMap(MemoryRegion region) : region_(region) {}
ALWAYS_INLINE bool IsValid() const { return region_.pointer() != nullptr; }
ALWAYS_INLINE uint32_t GetDexPc(const StackMapEncoding& encoding) const {
return encoding.GetDexPcEncoding().Load(region_);
}
ALWAYS_INLINE void SetDexPc(const StackMapEncoding& encoding, uint32_t dex_pc) {
encoding.GetDexPcEncoding().Store(region_, dex_pc);
}
ALWAYS_INLINE uint32_t GetNativePcOffset(const StackMapEncoding& encoding) const {
return encoding.GetNativePcEncoding().Load(region_);
}
ALWAYS_INLINE void SetNativePcOffset(const StackMapEncoding& encoding, uint32_t native_pc_offset) {
encoding.GetNativePcEncoding().Store(region_, native_pc_offset);
}
ALWAYS_INLINE uint32_t GetDexRegisterMapOffset(const StackMapEncoding& encoding) const {
return encoding.GetDexRegisterMapEncoding().Load(region_);
}
ALWAYS_INLINE void SetDexRegisterMapOffset(const StackMapEncoding& encoding, uint32_t offset) {
encoding.GetDexRegisterMapEncoding().Store(region_, offset);
}
ALWAYS_INLINE uint32_t GetInlineDescriptorOffset(const StackMapEncoding& encoding) const {
return encoding.GetInlineInfoEncoding().Load(region_);
}
ALWAYS_INLINE void SetInlineDescriptorOffset(const StackMapEncoding& encoding, uint32_t offset) {
encoding.GetInlineInfoEncoding().Store(region_, offset);
}
ALWAYS_INLINE uint32_t GetRegisterMask(const StackMapEncoding& encoding) const {
return encoding.GetRegisterMaskEncoding().Load(region_);
}
ALWAYS_INLINE void SetRegisterMask(const StackMapEncoding& encoding, uint32_t mask) {
encoding.GetRegisterMaskEncoding().Store(region_, mask);
}
ALWAYS_INLINE size_t GetNumberOfStackMaskBits(const StackMapEncoding& encoding) const {
return region_.size_in_bits() - encoding.GetStackMaskBitOffset();
}
ALWAYS_INLINE bool GetStackMaskBit(const StackMapEncoding& encoding, size_t index) const {
return region_.LoadBit(encoding.GetStackMaskBitOffset() + index);
}
ALWAYS_INLINE void SetStackMaskBit(const StackMapEncoding& encoding, size_t index, bool value) {
region_.StoreBit(encoding.GetStackMaskBitOffset() + index, value);
}
ALWAYS_INLINE bool HasDexRegisterMap(const StackMapEncoding& encoding) const {
return GetDexRegisterMapOffset(encoding) != kNoDexRegisterMap;
}
ALWAYS_INLINE bool HasInlineInfo(const StackMapEncoding& encoding) const {
return GetInlineDescriptorOffset(encoding) != kNoInlineInfo;
}
ALWAYS_INLINE bool Equals(const StackMap& other) const {
return region_.pointer() == other.region_.pointer() && region_.size() == other.region_.size();
}
void Dump(VariableIndentationOutputStream* vios,
const CodeInfo& code_info,
const CodeInfoEncoding& encoding,
uint32_t code_offset,
uint16_t number_of_dex_registers,
const std::string& header_suffix = "") const;
// Special (invalid) offset for the DexRegisterMapOffset field meaning
// that there is no Dex register map for this stack map.
static constexpr uint32_t kNoDexRegisterMap = -1;
// Special (invalid) offset for the InlineDescriptorOffset field meaning
// that there is no inline info for this stack map.
static constexpr uint32_t kNoInlineInfo = -1;
private:
static constexpr int kFixedSize = 0;
MemoryRegion region_;
friend class StackMapStream;
};
class InlineInfoEncoding {
public:
void SetFromSizes(size_t method_index_max,
size_t dex_pc_max,
size_t invoke_type_max,
size_t dex_register_map_size) {
total_bit_size_ = kMethodIndexBitOffset;
total_bit_size_ += MinimumBitsToStore(method_index_max);
dex_pc_bit_offset_ = dchecked_integral_cast<uint8_t>(total_bit_size_);
// Note: We're not encoding the dex pc if there is none. That's the case
// for an intrinsified native method, such as String.charAt().
if (dex_pc_max != DexFile::kDexNoIndex) {
total_bit_size_ += MinimumBitsToStore(1 /* kNoDexPc */ + dex_pc_max);
}
invoke_type_bit_offset_ = dchecked_integral_cast<uint8_t>(total_bit_size_);
total_bit_size_ += MinimumBitsToStore(invoke_type_max);
// We also need +1 for kNoDexRegisterMap, but since the size is strictly
// greater than any offset we might try to encode, we already implicitly have it.
dex_register_map_bit_offset_ = dchecked_integral_cast<uint8_t>(total_bit_size_);
total_bit_size_ += MinimumBitsToStore(dex_register_map_size);
}
ALWAYS_INLINE FieldEncoding GetMethodIndexEncoding() const {
return FieldEncoding(kMethodIndexBitOffset, dex_pc_bit_offset_);
}
ALWAYS_INLINE FieldEncoding GetDexPcEncoding() const {
return FieldEncoding(dex_pc_bit_offset_, invoke_type_bit_offset_, -1 /* min_value */);
}
ALWAYS_INLINE FieldEncoding GetInvokeTypeEncoding() const {
return FieldEncoding(invoke_type_bit_offset_, dex_register_map_bit_offset_);
}
ALWAYS_INLINE FieldEncoding GetDexRegisterMapEncoding() const {
return FieldEncoding(dex_register_map_bit_offset_, total_bit_size_, -1 /* min_value */);
}
ALWAYS_INLINE size_t GetEntrySize() const {
return RoundUp(total_bit_size_, kBitsPerByte) / kBitsPerByte;
}
void Dump(VariableIndentationOutputStream* vios) const;
private:
static constexpr uint8_t kIsLastBitOffset = 0;
static constexpr uint8_t kMethodIndexBitOffset = 1;
uint8_t dex_pc_bit_offset_;
uint8_t invoke_type_bit_offset_;
uint8_t dex_register_map_bit_offset_;
uint8_t total_bit_size_;
};
/**
* Inline information for a specific PC. The information is of the form:
*
* [is_last, method_index, dex_pc, invoke_type, dex_register_map_offset]+.
*/
class InlineInfo {
public:
explicit InlineInfo(MemoryRegion region) : region_(region) {
}
ALWAYS_INLINE uint32_t GetDepth(const InlineInfoEncoding& encoding) const {
size_t depth = 0;
while (!GetRegionAtDepth(encoding, depth++).LoadBit(0)) { } // Check is_last bit.
return depth;
}
ALWAYS_INLINE void SetDepth(const InlineInfoEncoding& encoding, uint32_t depth) {
DCHECK_GT(depth, 0u);
for (size_t d = 0; d < depth; ++d) {
GetRegionAtDepth(encoding, d).StoreBit(0, d == depth - 1); // Set is_last bit.
}
}
ALWAYS_INLINE uint32_t GetMethodIndexAtDepth(const InlineInfoEncoding& encoding,
uint32_t depth) const {
return encoding.GetMethodIndexEncoding().Load(GetRegionAtDepth(encoding, depth));
}
ALWAYS_INLINE void SetMethodIndexAtDepth(const InlineInfoEncoding& encoding,
uint32_t depth,
uint32_t index) {
encoding.GetMethodIndexEncoding().Store(GetRegionAtDepth(encoding, depth), index);
}
ALWAYS_INLINE uint32_t GetDexPcAtDepth(const InlineInfoEncoding& encoding,
uint32_t depth) const {
return encoding.GetDexPcEncoding().Load(GetRegionAtDepth(encoding, depth));
}
ALWAYS_INLINE void SetDexPcAtDepth(const InlineInfoEncoding& encoding,
uint32_t depth,
uint32_t dex_pc) {
encoding.GetDexPcEncoding().Store(GetRegionAtDepth(encoding, depth), dex_pc);
}
ALWAYS_INLINE uint32_t GetInvokeTypeAtDepth(const InlineInfoEncoding& encoding,
uint32_t depth) const {
return encoding.GetInvokeTypeEncoding().Load(GetRegionAtDepth(encoding, depth));
}
ALWAYS_INLINE void SetInvokeTypeAtDepth(const InlineInfoEncoding& encoding,
uint32_t depth,
uint32_t invoke_type) {
encoding.GetInvokeTypeEncoding().Store(GetRegionAtDepth(encoding, depth), invoke_type);
}
ALWAYS_INLINE uint32_t GetDexRegisterMapOffsetAtDepth(const InlineInfoEncoding& encoding,
uint32_t depth) const {
return encoding.GetDexRegisterMapEncoding().Load(GetRegionAtDepth(encoding, depth));
}
ALWAYS_INLINE void SetDexRegisterMapOffsetAtDepth(const InlineInfoEncoding& encoding,
uint32_t depth,
uint32_t offset) {
encoding.GetDexRegisterMapEncoding().Store(GetRegionAtDepth(encoding, depth), offset);
}
ALWAYS_INLINE bool HasDexRegisterMapAtDepth(const InlineInfoEncoding& encoding,
uint32_t depth) const {
return GetDexRegisterMapOffsetAtDepth(encoding, depth) != StackMap::kNoDexRegisterMap;
}
void Dump(VariableIndentationOutputStream* vios,
const CodeInfo& info,
uint16_t* number_of_dex_registers) const;
private:
ALWAYS_INLINE MemoryRegion GetRegionAtDepth(const InlineInfoEncoding& encoding,
uint32_t depth) const {
size_t entry_size = encoding.GetEntrySize();
DCHECK_GT(entry_size, 0u);
return region_.Subregion(depth * entry_size, entry_size);
}
MemoryRegion region_;
};
// Most of the fields are encoded as ULEB128 to save space.
struct CodeInfoEncoding {
uint32_t non_header_size;
uint32_t number_of_stack_maps;
uint32_t stack_map_size_in_bytes;
uint32_t number_of_location_catalog_entries;
StackMapEncoding stack_map_encoding;
InlineInfoEncoding inline_info_encoding;
uint8_t header_size;
CodeInfoEncoding() { }
explicit CodeInfoEncoding(const void* data) {
const uint8_t* ptr = reinterpret_cast<const uint8_t*>(data);
non_header_size = DecodeUnsignedLeb128(&ptr);
number_of_stack_maps = DecodeUnsignedLeb128(&ptr);
stack_map_size_in_bytes = DecodeUnsignedLeb128(&ptr);
number_of_location_catalog_entries = DecodeUnsignedLeb128(&ptr);
static_assert(alignof(StackMapEncoding) == 1,
"StackMapEncoding should not require alignment");
stack_map_encoding = *reinterpret_cast<const StackMapEncoding*>(ptr);
ptr += sizeof(StackMapEncoding);
if (stack_map_encoding.GetInlineInfoEncoding().BitSize() > 0) {
static_assert(alignof(InlineInfoEncoding) == 1,
"InlineInfoEncoding should not require alignment");
inline_info_encoding = *reinterpret_cast<const InlineInfoEncoding*>(ptr);
ptr += sizeof(InlineInfoEncoding);
} else {
inline_info_encoding = InlineInfoEncoding{}; // NOLINT.
}
header_size = dchecked_integral_cast<uint8_t>(ptr - reinterpret_cast<const uint8_t*>(data));
}
template<typename Vector>
void Compress(Vector* dest) const {
EncodeUnsignedLeb128(dest, non_header_size);
EncodeUnsignedLeb128(dest, number_of_stack_maps);
EncodeUnsignedLeb128(dest, stack_map_size_in_bytes);
EncodeUnsignedLeb128(dest, number_of_location_catalog_entries);
const uint8_t* stack_map_ptr = reinterpret_cast<const uint8_t*>(&stack_map_encoding);
dest->insert(dest->end(), stack_map_ptr, stack_map_ptr + sizeof(StackMapEncoding));
if (stack_map_encoding.GetInlineInfoEncoding().BitSize() > 0) {
const uint8_t* inline_info_ptr = reinterpret_cast<const uint8_t*>(&inline_info_encoding);
dest->insert(dest->end(), inline_info_ptr, inline_info_ptr + sizeof(InlineInfoEncoding));
}
}
};
/**
* Wrapper around all compiler information collected for a method.
* The information is of the form:
*
* [CodeInfoEncoding, StackMap+, DexRegisterLocationCatalog+, DexRegisterMap+, InlineInfo*]
*
* where CodeInfoEncoding is of the form:
*
* [non_header_size, number_of_stack_maps, stack_map_size_in_bytes,
* number_of_location_catalog_entries, StackMapEncoding]
*/
class CodeInfo {
public:
explicit CodeInfo(MemoryRegion region) : region_(region) {
}
explicit CodeInfo(const void* data) {
CodeInfoEncoding encoding = CodeInfoEncoding(data);
region_ = MemoryRegion(const_cast<void*>(data),
encoding.header_size + encoding.non_header_size);
}
CodeInfoEncoding ExtractEncoding() const {
return CodeInfoEncoding(region_.start());
}
bool HasInlineInfo(const CodeInfoEncoding& encoding) const {
return encoding.stack_map_encoding.GetInlineInfoEncoding().BitSize() > 0;
}
DexRegisterLocationCatalog GetDexRegisterLocationCatalog(const CodeInfoEncoding& encoding) const {
return DexRegisterLocationCatalog(region_.Subregion(
GetDexRegisterLocationCatalogOffset(encoding),
GetDexRegisterLocationCatalogSize(encoding)));
}
StackMap GetStackMapAt(size_t i, const CodeInfoEncoding& encoding) const {
size_t stack_map_size = encoding.stack_map_size_in_bytes;
return StackMap(GetStackMaps(encoding).Subregion(i * stack_map_size, stack_map_size));
}
uint32_t GetNumberOfLocationCatalogEntries(const CodeInfoEncoding& encoding) const {
return encoding.number_of_location_catalog_entries;
}
uint32_t GetDexRegisterLocationCatalogSize(const CodeInfoEncoding& encoding) const {
return ComputeDexRegisterLocationCatalogSize(GetDexRegisterLocationCatalogOffset(encoding),
GetNumberOfLocationCatalogEntries(encoding));
}
uint32_t GetNumberOfStackMaps(const CodeInfoEncoding& encoding) const {
return encoding.number_of_stack_maps;
}
// Get the size of all the stack maps of this CodeInfo object, in bytes.
size_t GetStackMapsSize(const CodeInfoEncoding& encoding) const {
return encoding.stack_map_size_in_bytes * GetNumberOfStackMaps(encoding);
}
uint32_t GetDexRegisterLocationCatalogOffset(const CodeInfoEncoding& encoding) const {
return GetStackMapsOffset(encoding) + GetStackMapsSize(encoding);
}
size_t GetDexRegisterMapsOffset(const CodeInfoEncoding& encoding) const {
return GetDexRegisterLocationCatalogOffset(encoding)
+ GetDexRegisterLocationCatalogSize(encoding);
}
uint32_t GetStackMapsOffset(const CodeInfoEncoding& encoding) const {
return encoding.header_size;
}
DexRegisterMap GetDexRegisterMapOf(StackMap stack_map,
const CodeInfoEncoding& encoding,
uint32_t number_of_dex_registers) const {
if (!stack_map.HasDexRegisterMap(encoding.stack_map_encoding)) {
return DexRegisterMap();
} else {
uint32_t offset = GetDexRegisterMapsOffset(encoding)
+ stack_map.GetDexRegisterMapOffset(encoding.stack_map_encoding);
size_t size = ComputeDexRegisterMapSizeOf(encoding, offset, number_of_dex_registers);
return DexRegisterMap(region_.Subregion(offset, size));
}
}
// Return the `DexRegisterMap` pointed by `inline_info` at depth `depth`.
DexRegisterMap GetDexRegisterMapAtDepth(uint8_t depth,
InlineInfo inline_info,
const CodeInfoEncoding& encoding,
uint32_t number_of_dex_registers) const {
if (!inline_info.HasDexRegisterMapAtDepth(encoding.inline_info_encoding, depth)) {
return DexRegisterMap();
} else {
uint32_t offset = GetDexRegisterMapsOffset(encoding) +
inline_info.GetDexRegisterMapOffsetAtDepth(encoding.inline_info_encoding, depth);
size_t size = ComputeDexRegisterMapSizeOf(encoding, offset, number_of_dex_registers);
return DexRegisterMap(region_.Subregion(offset, size));
}
}
InlineInfo GetInlineInfoOf(StackMap stack_map, const CodeInfoEncoding& encoding) const {
DCHECK(stack_map.HasInlineInfo(encoding.stack_map_encoding));
uint32_t offset = stack_map.GetInlineDescriptorOffset(encoding.stack_map_encoding)
+ GetDexRegisterMapsOffset(encoding);
return InlineInfo(region_.Subregion(offset, region_.size() - offset));
}
StackMap GetStackMapForDexPc(uint32_t dex_pc, const CodeInfoEncoding& encoding) const {
for (size_t i = 0, e = GetNumberOfStackMaps(encoding); i < e; ++i) {
StackMap stack_map = GetStackMapAt(i, encoding);
if (stack_map.GetDexPc(encoding.stack_map_encoding) == dex_pc) {
return stack_map;
}
}
return StackMap();
}
// Searches the stack map list backwards because catch stack maps are stored
// at the end.
StackMap GetCatchStackMapForDexPc(uint32_t dex_pc, const CodeInfoEncoding& encoding) const {
for (size_t i = GetNumberOfStackMaps(encoding); i > 0; --i) {
StackMap stack_map = GetStackMapAt(i - 1, encoding);
if (stack_map.GetDexPc(encoding.stack_map_encoding) == dex_pc) {
return stack_map;
}
}
return StackMap();
}
StackMap GetOsrStackMapForDexPc(uint32_t dex_pc, const CodeInfoEncoding& encoding) const {
size_t e = GetNumberOfStackMaps(encoding);
if (e == 0) {
// There cannot be OSR stack map if there is no stack map.
return StackMap();
}
// Walk over all stack maps. If two consecutive stack maps are identical, then we
// have found a stack map suitable for OSR.
const StackMapEncoding& stack_map_encoding = encoding.stack_map_encoding;
for (size_t i = 0; i < e - 1; ++i) {
StackMap stack_map = GetStackMapAt(i, encoding);
if (stack_map.GetDexPc(stack_map_encoding) == dex_pc) {
StackMap other = GetStackMapAt(i + 1, encoding);
if (other.GetDexPc(stack_map_encoding) == dex_pc &&
other.GetNativePcOffset(stack_map_encoding) ==
stack_map.GetNativePcOffset(stack_map_encoding)) {
DCHECK_EQ(other.GetDexRegisterMapOffset(stack_map_encoding),
stack_map.GetDexRegisterMapOffset(stack_map_encoding));
DCHECK(!stack_map.HasInlineInfo(stack_map_encoding));
if (i < e - 2) {
// Make sure there are not three identical stack maps following each other.
DCHECK_NE(stack_map.GetNativePcOffset(stack_map_encoding),
GetStackMapAt(i + 2, encoding).GetNativePcOffset(stack_map_encoding));
}
return stack_map;
}
}
}
return StackMap();
}
StackMap GetStackMapForNativePcOffset(uint32_t native_pc_offset,
const CodeInfoEncoding& encoding) const {
// TODO: Safepoint stack maps are sorted by native_pc_offset but catch stack
// maps are not. If we knew that the method does not have try/catch,
// we could do binary search.
for (size_t i = 0, e = GetNumberOfStackMaps(encoding); i < e; ++i) {
StackMap stack_map = GetStackMapAt(i, encoding);
if (stack_map.GetNativePcOffset(encoding.stack_map_encoding) == native_pc_offset) {
return stack_map;
}
}
return StackMap();
}
// Dump this CodeInfo object on `os`. `code_offset` is the (absolute)
// native PC of the compiled method and `number_of_dex_registers` the
// number of Dex virtual registers used in this method. If
// `dump_stack_maps` is true, also dump the stack maps and the
// associated Dex register maps.
void Dump(VariableIndentationOutputStream* vios,
uint32_t code_offset,
uint16_t number_of_dex_registers,
bool dump_stack_maps) const;
private:
MemoryRegion GetStackMaps(const CodeInfoEncoding& encoding) const {
return region_.size() == 0
? MemoryRegion()
: region_.Subregion(GetStackMapsOffset(encoding), GetStackMapsSize(encoding));
}
// Compute the size of the Dex register map associated to the stack map at
// `dex_register_map_offset_in_code_info`.
size_t ComputeDexRegisterMapSizeOf(const CodeInfoEncoding& encoding,
uint32_t dex_register_map_offset_in_code_info,
uint16_t number_of_dex_registers) const {
// Offset where the actual mapping data starts within art::DexRegisterMap.
size_t location_mapping_data_offset_in_dex_register_map =
DexRegisterMap::GetLocationMappingDataOffset(number_of_dex_registers);
// Create a temporary art::DexRegisterMap to be able to call
// art::DexRegisterMap::GetNumberOfLiveDexRegisters and
DexRegisterMap dex_register_map_without_locations(
MemoryRegion(region_.Subregion(dex_register_map_offset_in_code_info,
location_mapping_data_offset_in_dex_register_map)));
size_t number_of_live_dex_registers =
dex_register_map_without_locations.GetNumberOfLiveDexRegisters(number_of_dex_registers);
size_t location_mapping_data_size_in_bits =
DexRegisterMap::SingleEntrySizeInBits(GetNumberOfLocationCatalogEntries(encoding))
* number_of_live_dex_registers;
size_t location_mapping_data_size_in_bytes =
RoundUp(location_mapping_data_size_in_bits, kBitsPerByte) / kBitsPerByte;
size_t dex_register_map_size =
location_mapping_data_offset_in_dex_register_map + location_mapping_data_size_in_bytes;
return dex_register_map_size;
}
// Compute the size of a Dex register location catalog starting at offset `origin`
// in `region_` and containing `number_of_dex_locations` entries.
size_t ComputeDexRegisterLocationCatalogSize(uint32_t origin,
uint32_t number_of_dex_locations) const {
// TODO: Ideally, we would like to use art::DexRegisterLocationCatalog::Size or
// art::DexRegisterLocationCatalog::FindLocationOffset, but the
// DexRegisterLocationCatalog is not yet built. Try to factor common code.
size_t offset = origin + DexRegisterLocationCatalog::kFixedSize;
// Skip the first `number_of_dex_locations - 1` entries.
for (uint16_t i = 0; i < number_of_dex_locations; ++i) {
// Read the first next byte and inspect its first 3 bits to decide
// whether it is a short or a large location.
DexRegisterLocationCatalog::ShortLocation first_byte =
region_.LoadUnaligned<DexRegisterLocationCatalog::ShortLocation>(offset);
DexRegisterLocation::Kind kind =
DexRegisterLocationCatalog::ExtractKindFromShortLocation(first_byte);
if (DexRegisterLocation::IsShortLocationKind(kind)) {
// Short location. Skip the current byte.
offset += DexRegisterLocationCatalog::SingleShortEntrySize();
} else {
// Large location. Skip the 5 next bytes.
offset += DexRegisterLocationCatalog::SingleLargeEntrySize();
}
}
size_t size = offset - origin;
return size;
}
MemoryRegion region_;
friend class StackMapStream;
};
#undef ELEMENT_BYTE_OFFSET_AFTER
#undef ELEMENT_BIT_OFFSET_AFTER
} // namespace art
#endif // ART_RUNTIME_STACK_MAP_H_