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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 <limits>
#include "arch/instruction_set.h"
#include "base/bit_memory_region.h"
#include "base/bit_table.h"
#include "base/bit_utils.h"
#include "base/bit_vector.h"
#include "base/leb128.h"
#include "base/memory_region.h"
#include "dex/dex_file_types.h"
#include "dex_register_location.h"
#include "quick/quick_method_frame_info.h"
namespace art {
class OatQuickMethodHeader;
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;
// The delta compression of dex register maps means we need to scan the stackmaps backwards.
// We compress the data in such a way so that there is an upper bound on the search distance.
// Max distance 0 means each stack map must be fully defined and no scanning back is allowed.
// If this value is changed, the oat file version should be incremented (for DCHECK to pass).
static constexpr size_t kMaxDexRegisterMapSearchDistance = 32;
class ArtMethod;
class CodeInfo;
class Stats;
std::ostream& operator<<(std::ostream& stream, const DexRegisterLocation& reg);
// Information on Dex register locations for a specific PC.
// Effectively just a convenience wrapper for DexRegisterLocation vector.
// If the size is small enough, it keeps the data on the stack.
// TODO: Replace this with generic purpose "small-vector" implementation.
class DexRegisterMap {
public:
using iterator = DexRegisterLocation*;
using const_iterator = const DexRegisterLocation*;
// Create map for given number of registers and initialize them to the given value.
DexRegisterMap(size_t count, DexRegisterLocation value) : count_(count), regs_small_{} {
if (count_ <= kSmallCount) {
std::fill_n(regs_small_.begin(), count, value);
} else {
regs_large_.resize(count, value);
}
}
DexRegisterLocation* data() {
return count_ <= kSmallCount ? regs_small_.data() : regs_large_.data();
}
const DexRegisterLocation* data() const {
return count_ <= kSmallCount ? regs_small_.data() : regs_large_.data();
}
iterator begin() { return data(); }
iterator end() { return data() + count_; }
const_iterator begin() const { return data(); }
const_iterator end() const { return data() + count_; }
size_t size() const { return count_; }
bool empty() const { return count_ == 0; }
DexRegisterLocation& operator[](size_t index) {
DCHECK_LT(index, count_);
return data()[index];
}
const DexRegisterLocation& operator[](size_t index) const {
DCHECK_LT(index, count_);
return data()[index];
}
size_t GetNumberOfLiveDexRegisters() const {
return std::count_if(begin(), end(), [](auto& loc) { return loc.IsLive(); });
}
bool HasAnyLiveDexRegisters() const {
return std::any_of(begin(), end(), [](auto& loc) { return loc.IsLive(); });
}
void Dump(VariableIndentationOutputStream* vios) const;
private:
// Store the data inline if the number of registers is small to avoid memory allocations.
// If count_ <= kSmallCount, we use the regs_small_ array, and regs_large_ otherwise.
static constexpr size_t kSmallCount = 16;
size_t count_;
std::array<DexRegisterLocation, kSmallCount> regs_small_;
dchecked_vector<DexRegisterLocation> regs_large_;
};
/**
* 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.
*/
class StackMap : public BitTableAccessor<8> {
public:
enum Kind {
Default = -1,
Catch = 0,
OSR = 1,
Debug = 2,
};
BIT_TABLE_HEADER(StackMap)
BIT_TABLE_COLUMN(0, Kind)
BIT_TABLE_COLUMN(1, PackedNativePc)
BIT_TABLE_COLUMN(2, DexPc)
BIT_TABLE_COLUMN(3, RegisterMaskIndex)
BIT_TABLE_COLUMN(4, StackMaskIndex)
BIT_TABLE_COLUMN(5, InlineInfoIndex)
BIT_TABLE_COLUMN(6, DexRegisterMaskIndex)
BIT_TABLE_COLUMN(7, DexRegisterMapIndex)
ALWAYS_INLINE uint32_t GetNativePcOffset(InstructionSet instruction_set) const {
return UnpackNativePc(GetPackedNativePc(), instruction_set);
}
ALWAYS_INLINE bool HasInlineInfo() const {
return HasInlineInfoIndex();
}
ALWAYS_INLINE bool HasDexRegisterMap() const {
return HasDexRegisterMapIndex();
}
static uint32_t PackNativePc(uint32_t native_pc, InstructionSet isa) {
DCHECK_ALIGNED_PARAM(native_pc, GetInstructionSetInstructionAlignment(isa));
return native_pc / GetInstructionSetInstructionAlignment(isa);
}
static uint32_t UnpackNativePc(uint32_t packed_native_pc, InstructionSet isa) {
uint32_t native_pc = packed_native_pc * GetInstructionSetInstructionAlignment(isa);
DCHECK_EQ(native_pc / GetInstructionSetInstructionAlignment(isa), packed_native_pc);
return native_pc;
}
void Dump(VariableIndentationOutputStream* vios,
const CodeInfo& code_info,
uint32_t code_offset,
InstructionSet instruction_set) const;
};
/**
* Inline information for a specific PC.
* The row referenced from the StackMap holds information at depth 0.
* Following rows hold information for further depths.
*/
class InlineInfo : public BitTableAccessor<6> {
public:
BIT_TABLE_HEADER(InlineInfo)
BIT_TABLE_COLUMN(0, IsLast) // Determines if there are further rows for further depths.
BIT_TABLE_COLUMN(1, DexPc)
BIT_TABLE_COLUMN(2, MethodInfoIndex)
BIT_TABLE_COLUMN(3, ArtMethodHi) // High bits of ArtMethod*.
BIT_TABLE_COLUMN(4, ArtMethodLo) // Low bits of ArtMethod*.
BIT_TABLE_COLUMN(5, NumberOfDexRegisters) // Includes outer levels and the main method.
BIT_TABLE_COLUMN(6, DexRegisterMapIndex)
static constexpr uint32_t kLast = -1;
static constexpr uint32_t kMore = 0;
bool EncodesArtMethod() const {
return HasArtMethodLo();
}
ArtMethod* GetArtMethod() const {
uint64_t lo = GetArtMethodLo();
uint64_t hi = GetArtMethodHi();
return reinterpret_cast<ArtMethod*>((hi << 32) | lo);
}
void Dump(VariableIndentationOutputStream* vios,
const CodeInfo& info,
const StackMap& stack_map) const;
};
class StackMask : public BitTableAccessor<1> {
public:
BIT_TABLE_HEADER(StackMask)
BIT_TABLE_COLUMN(0, Mask)
};
class DexRegisterMask : public BitTableAccessor<1> {
public:
BIT_TABLE_HEADER(DexRegisterMask)
BIT_TABLE_COLUMN(0, Mask)
};
class DexRegisterMapInfo : public BitTableAccessor<1> {
public:
BIT_TABLE_HEADER(DexRegisterMapInfo)
BIT_TABLE_COLUMN(0, CatalogueIndex)
};
class DexRegisterInfo : public BitTableAccessor<2> {
public:
BIT_TABLE_HEADER(DexRegisterInfo)
BIT_TABLE_COLUMN(0, Kind)
BIT_TABLE_COLUMN(1, PackedValue)
ALWAYS_INLINE DexRegisterLocation GetLocation() const {
DexRegisterLocation::Kind kind = static_cast<DexRegisterLocation::Kind>(GetKind());
return DexRegisterLocation(kind, UnpackValue(kind, GetPackedValue()));
}
static uint32_t PackValue(DexRegisterLocation::Kind kind, uint32_t value) {
uint32_t packed_value = value;
if (kind == DexRegisterLocation::Kind::kInStack) {
DCHECK(IsAligned<kFrameSlotSize>(packed_value));
packed_value /= kFrameSlotSize;
}
return packed_value;
}
static uint32_t UnpackValue(DexRegisterLocation::Kind kind, uint32_t packed_value) {
uint32_t value = packed_value;
if (kind == DexRegisterLocation::Kind::kInStack) {
value *= kFrameSlotSize;
}
return value;
}
};
// Register masks tend to have many trailing zero bits (caller-saves are usually not encoded),
// therefore it is worth encoding the mask as value+shift.
class RegisterMask : public BitTableAccessor<2> {
public:
BIT_TABLE_HEADER(RegisterMask)
BIT_TABLE_COLUMN(0, Value)
BIT_TABLE_COLUMN(1, Shift)
ALWAYS_INLINE uint32_t GetMask() const {
return GetValue() << GetShift();
}
};
// Method indices are not very dedup friendly.
// Separating them greatly improves dedup efficiency of the other tables.
class MethodInfo : public BitTableAccessor<1> {
public:
BIT_TABLE_HEADER(MethodInfo)
BIT_TABLE_COLUMN(0, MethodIndex)
};
/**
* Wrapper around all compiler information collected for a method.
* See the Decode method at the end for the precise binary format.
*/
class CodeInfo {
public:
class Deduper {
public:
explicit Deduper(std::vector<uint8_t>* output) : writer_(output) {
DCHECK_EQ(output->size(), 0u);
}
// Copy CodeInfo into output while de-duplicating the internal bit tables.
// It returns the byte offset of the copied CodeInfo within the output.
size_t Dedupe(const uint8_t* code_info);
private:
BitMemoryWriter<std::vector<uint8_t>> writer_;
// Deduplicate at BitTable level. The value is bit offset within the output.
std::map<BitMemoryRegion, uint32_t, BitMemoryRegion::Less> dedupe_map_;
};
enum DecodeFlags {
AllTables = 0,
// Limits the decoding only to the data needed by GC.
GcMasksOnly = 1,
// Limits the decoding only to the main stack map table and inline info table.
// This is sufficient for many use cases and makes the header decoding faster.
InlineInfoOnly = 2,
};
CodeInfo() {}
explicit CodeInfo(const uint8_t* data, DecodeFlags flags = AllTables) {
Decode(reinterpret_cast<const uint8_t*>(data), flags);
}
explicit CodeInfo(const OatQuickMethodHeader* header, DecodeFlags flags = AllTables);
size_t Size() const {
return BitsToBytesRoundUp(size_in_bits_);
}
ALWAYS_INLINE const BitTable<StackMap>& GetStackMaps() const {
return stack_maps_;
}
ALWAYS_INLINE StackMap GetStackMapAt(size_t index) const {
return stack_maps_.GetRow(index);
}
BitMemoryRegion GetStackMask(size_t index) const {
return stack_masks_.GetBitMemoryRegion(index);
}
BitMemoryRegion GetStackMaskOf(const StackMap& stack_map) const {
uint32_t index = stack_map.GetStackMaskIndex();
return (index == StackMap::kNoValue) ? BitMemoryRegion() : GetStackMask(index);
}
uint32_t GetRegisterMaskOf(const StackMap& stack_map) const {
uint32_t index = stack_map.GetRegisterMaskIndex();
return (index == StackMap::kNoValue) ? 0 : register_masks_.GetRow(index).GetMask();
}
uint32_t GetNumberOfLocationCatalogEntries() const {
return dex_register_catalog_.NumRows();
}
ALWAYS_INLINE DexRegisterLocation GetDexRegisterCatalogEntry(size_t index) const {
return (index == StackMap::kNoValue)
? DexRegisterLocation::None()
: dex_register_catalog_.GetRow(index).GetLocation();
}
bool HasInlineInfo() const {
return inline_infos_.NumRows() > 0;
}
uint32_t GetNumberOfStackMaps() const {
return stack_maps_.NumRows();
}
uint32_t GetMethodIndexOf(InlineInfo inline_info) const {
return method_infos_.GetRow(inline_info.GetMethodInfoIndex()).GetMethodIndex();
}
ALWAYS_INLINE DexRegisterMap GetDexRegisterMapOf(StackMap stack_map) const {
if (stack_map.HasDexRegisterMap()) {
DexRegisterMap map(number_of_dex_registers_, DexRegisterLocation::Invalid());
DecodeDexRegisterMap(stack_map.Row(), /* first_dex_register= */ 0, &map);
return map;
}
return DexRegisterMap(0, DexRegisterLocation::None());
}
ALWAYS_INLINE DexRegisterMap GetInlineDexRegisterMapOf(StackMap stack_map,
InlineInfo inline_info) const {
if (stack_map.HasDexRegisterMap()) {
DCHECK(stack_map.HasInlineInfoIndex());
uint32_t depth = inline_info.Row() - stack_map.GetInlineInfoIndex();
// The register counts are commutative and include all outer levels.
// This allows us to determine the range [first, last) in just two lookups.
// If we are at depth 0 (the first inlinee), the count from the main method is used.
uint32_t first = (depth == 0)
? number_of_dex_registers_
: inline_infos_.GetRow(inline_info.Row() - 1).GetNumberOfDexRegisters();
uint32_t last = inline_info.GetNumberOfDexRegisters();
DexRegisterMap map(last - first, DexRegisterLocation::Invalid());
DecodeDexRegisterMap(stack_map.Row(), first, &map);
return map;
}
return DexRegisterMap(0, DexRegisterLocation::None());
}
BitTableRange<InlineInfo> GetInlineInfosOf(StackMap stack_map) const {
uint32_t index = stack_map.GetInlineInfoIndex();
if (index != StackMap::kNoValue) {
auto begin = inline_infos_.begin() + index;
auto end = begin;
while ((*end++).GetIsLast() == InlineInfo::kMore) { }
return BitTableRange<InlineInfo>(begin, end);
} else {
return BitTableRange<InlineInfo>();
}
}
StackMap GetStackMapForDexPc(uint32_t dex_pc) const {
for (StackMap stack_map : stack_maps_) {
if (stack_map.GetDexPc() == dex_pc && stack_map.GetKind() != StackMap::Kind::Debug) {
return stack_map;
}
}
return stack_maps_.GetInvalidRow();
}
// Searches the stack map list backwards because catch stack maps are stored at the end.
StackMap GetCatchStackMapForDexPc(uint32_t dex_pc) const {
for (size_t i = GetNumberOfStackMaps(); i > 0; --i) {
StackMap stack_map = GetStackMapAt(i - 1);
if (stack_map.GetDexPc() == dex_pc && stack_map.GetKind() == StackMap::Kind::Catch) {
return stack_map;
}
}
return stack_maps_.GetInvalidRow();
}
StackMap GetOsrStackMapForDexPc(uint32_t dex_pc) const {
for (StackMap stack_map : stack_maps_) {
if (stack_map.GetDexPc() == dex_pc && stack_map.GetKind() == StackMap::Kind::OSR) {
return stack_map;
}
}
return stack_maps_.GetInvalidRow();
}
StackMap GetStackMapForNativePcOffset(uint32_t pc, InstructionSet isa = kRuntimeISA) const;
// Dump this CodeInfo object on `vios`.
// `code_offset` is the (absolute) native PC of the compiled method.
void Dump(VariableIndentationOutputStream* vios,
uint32_t code_offset,
bool verbose,
InstructionSet instruction_set) const;
// Accumulate code info size statistics into the given Stats tree.
static void CollectSizeStats(const uint8_t* code_info, /*out*/ Stats* parent);
ALWAYS_INLINE static QuickMethodFrameInfo DecodeFrameInfo(const uint8_t* data) {
BitMemoryReader reader(data);
return QuickMethodFrameInfo(
reader.ReadVarint() * kStackAlignment, // Decode packed_frame_size_ and unpack.
reader.ReadVarint(), // core_spill_mask_.
reader.ReadVarint()); // fp_spill_mask_.
}
private:
// Returns lower bound (fist stack map which has pc greater or equal than the desired one).
// It ignores catch stack maps at the end (it is the same as if they had maximum pc value).
BitTable<StackMap>::const_iterator BinarySearchNativePc(uint32_t packed_pc) const;
// Scan backward to determine dex register locations at given stack map.
void DecodeDexRegisterMap(uint32_t stack_map_index,
uint32_t first_dex_register,
/*out*/ DexRegisterMap* map) const;
void Decode(const uint8_t* data, DecodeFlags flags);
// Invokes the callback with member pointer of each header field.
template<typename Callback>
ALWAYS_INLINE static void ForEachHeaderField(Callback callback) {
callback(&CodeInfo::packed_frame_size_);
callback(&CodeInfo::core_spill_mask_);
callback(&CodeInfo::fp_spill_mask_);
callback(&CodeInfo::number_of_dex_registers_);
}
// Invokes the callback with member pointer of each BitTable field.
template<typename Callback>
ALWAYS_INLINE static void ForEachBitTableField(Callback callback, DecodeFlags flags = AllTables) {
callback(&CodeInfo::stack_maps_);
callback(&CodeInfo::register_masks_);
callback(&CodeInfo::stack_masks_);
if (flags & DecodeFlags::GcMasksOnly) {
return;
}
callback(&CodeInfo::inline_infos_);
callback(&CodeInfo::method_infos_);
if (flags & DecodeFlags::InlineInfoOnly) {
return;
}
callback(&CodeInfo::dex_register_masks_);
callback(&CodeInfo::dex_register_maps_);
callback(&CodeInfo::dex_register_catalog_);
}
uint32_t packed_frame_size_ = 0; // Frame size in kStackAlignment units.
uint32_t core_spill_mask_ = 0;
uint32_t fp_spill_mask_ = 0;
uint32_t number_of_dex_registers_ = 0;
BitTable<StackMap> stack_maps_;
BitTable<RegisterMask> register_masks_;
BitTable<StackMask> stack_masks_;
BitTable<InlineInfo> inline_infos_;
BitTable<MethodInfo> method_infos_;
BitTable<DexRegisterMask> dex_register_masks_;
BitTable<DexRegisterMapInfo> dex_register_maps_;
BitTable<DexRegisterInfo> dex_register_catalog_;
uint32_t size_in_bits_ = 0;
};
#undef ELEMENT_BYTE_OFFSET_AFTER
#undef ELEMENT_BIT_OFFSET_AFTER
} // namespace art
#endif // ART_RUNTIME_STACK_MAP_H_