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//===- StackMapParser.h - StackMap Parsing Support --------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_OBJECT_STACKMAPPARSER_H
#define LLVM_OBJECT_STACKMAPPARSER_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Object/ELF.h"
#include "llvm/Support/Endian.h"
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <vector>
namespace llvm {
/// A parser for the latest stackmap format. At the moment, latest=V3.
template <llvm::endianness Endianness> class StackMapParser {
public:
template <typename AccessorT>
class AccessorIterator {
public:
AccessorIterator(AccessorT A) : A(A) {}
AccessorIterator& operator++() { A = A.next(); return *this; }
AccessorIterator operator++(int) {
auto tmp = *this;
++*this;
return tmp;
}
bool operator==(const AccessorIterator &Other) const {
return A.P == Other.A.P;
}
bool operator!=(const AccessorIterator &Other) const {
return !(*this == Other);
}
AccessorT& operator*() { return A; }
AccessorT* operator->() { return &A; }
private:
AccessorT A;
};
/// Accessor for function records.
class FunctionAccessor {
friend class StackMapParser;
public:
/// Get the function address.
uint64_t getFunctionAddress() const {
return read<uint64_t>(P);
}
/// Get the function's stack size.
uint64_t getStackSize() const {
return read<uint64_t>(P + sizeof(uint64_t));
}
/// Get the number of callsite records.
uint64_t getRecordCount() const {
return read<uint64_t>(P + (2 * sizeof(uint64_t)));
}
private:
FunctionAccessor(const uint8_t *P) : P(P) {}
const static int FunctionAccessorSize = 3 * sizeof(uint64_t);
FunctionAccessor next() const {
return FunctionAccessor(P + FunctionAccessorSize);
}
const uint8_t *P;
};
/// Accessor for constants.
class ConstantAccessor {
friend class StackMapParser;
public:
/// Return the value of this constant.
uint64_t getValue() const { return read<uint64_t>(P); }
private:
ConstantAccessor(const uint8_t *P) : P(P) {}
const static int ConstantAccessorSize = sizeof(uint64_t);
ConstantAccessor next() const {
return ConstantAccessor(P + ConstantAccessorSize);
}
const uint8_t *P;
};
enum class LocationKind : uint8_t {
Register = 1, Direct = 2, Indirect = 3, Constant = 4, ConstantIndex = 5
};
/// Accessor for location records.
class LocationAccessor {
friend class StackMapParser;
friend class RecordAccessor;
public:
/// Get the Kind for this location.
LocationKind getKind() const {
return LocationKind(P[KindOffset]);
}
/// Get the Size for this location.
unsigned getSizeInBytes() const {
return read<uint16_t>(P + SizeOffset);
}
/// Get the Dwarf register number for this location.
uint16_t getDwarfRegNum() const {
return read<uint16_t>(P + DwarfRegNumOffset);
}
/// Get the small-constant for this location. (Kind must be Constant).
uint32_t getSmallConstant() const {
assert(getKind() == LocationKind::Constant && "Not a small constant.");
return read<uint32_t>(P + SmallConstantOffset);
}
/// Get the constant-index for this location. (Kind must be ConstantIndex).
uint32_t getConstantIndex() const {
assert(getKind() == LocationKind::ConstantIndex &&
"Not a constant-index.");
return read<uint32_t>(P + SmallConstantOffset);
}
/// Get the offset for this location. (Kind must be Direct or Indirect).
int32_t getOffset() const {
assert((getKind() == LocationKind::Direct ||
getKind() == LocationKind::Indirect) &&
"Not direct or indirect.");
return read<int32_t>(P + SmallConstantOffset);
}
private:
LocationAccessor(const uint8_t *P) : P(P) {}
LocationAccessor next() const {
return LocationAccessor(P + LocationAccessorSize);
}
static const int KindOffset = 0;
static const int SizeOffset = KindOffset + sizeof(uint16_t);
static const int DwarfRegNumOffset = SizeOffset + sizeof(uint16_t);
static const int SmallConstantOffset = DwarfRegNumOffset + sizeof(uint32_t);
static const int LocationAccessorSize = sizeof(uint64_t) + sizeof(uint32_t);
const uint8_t *P;
};
/// Accessor for stackmap live-out fields.
class LiveOutAccessor {
friend class StackMapParser;
friend class RecordAccessor;
public:
/// Get the Dwarf register number for this live-out.
uint16_t getDwarfRegNum() const {
return read<uint16_t>(P + DwarfRegNumOffset);
}
/// Get the size in bytes of live [sub]register.
unsigned getSizeInBytes() const {
return read<uint8_t>(P + SizeOffset);
}
private:
LiveOutAccessor(const uint8_t *P) : P(P) {}
LiveOutAccessor next() const {
return LiveOutAccessor(P + LiveOutAccessorSize);
}
static const int DwarfRegNumOffset = 0;
static const int SizeOffset =
DwarfRegNumOffset + sizeof(uint16_t) + sizeof(uint8_t);
static const int LiveOutAccessorSize = sizeof(uint32_t);
const uint8_t *P;
};
/// Accessor for stackmap records.
class RecordAccessor {
friend class StackMapParser;
public:
using location_iterator = AccessorIterator<LocationAccessor>;
using liveout_iterator = AccessorIterator<LiveOutAccessor>;
/// Get the patchpoint/stackmap ID for this record.
uint64_t getID() const {
return read<uint64_t>(P + PatchpointIDOffset);
}
/// Get the instruction offset (from the start of the containing function)
/// for this record.
uint32_t getInstructionOffset() const {
return read<uint32_t>(P + InstructionOffsetOffset);
}
/// Get the number of locations contained in this record.
uint16_t getNumLocations() const {
return read<uint16_t>(P + NumLocationsOffset);
}
/// Get the location with the given index.
LocationAccessor getLocation(unsigned LocationIndex) const {
unsigned LocationOffset =
LocationListOffset + LocationIndex * LocationSize;
return LocationAccessor(P + LocationOffset);
}
/// Begin iterator for locations.
location_iterator location_begin() const {
return location_iterator(getLocation(0));
}
/// End iterator for locations.
location_iterator location_end() const {
return location_iterator(getLocation(getNumLocations()));
}
/// Iterator range for locations.
iterator_range<location_iterator> locations() const {
return make_range(location_begin(), location_end());
}
/// Get the number of liveouts contained in this record.
uint16_t getNumLiveOuts() const {
return read<uint16_t>(P + getNumLiveOutsOffset());
}
/// Get the live-out with the given index.
LiveOutAccessor getLiveOut(unsigned LiveOutIndex) const {
unsigned LiveOutOffset =
getNumLiveOutsOffset() + sizeof(uint16_t) + LiveOutIndex * LiveOutSize;
return LiveOutAccessor(P + LiveOutOffset);
}
/// Begin iterator for live-outs.
liveout_iterator liveouts_begin() const {
return liveout_iterator(getLiveOut(0));
}
/// End iterator for live-outs.
liveout_iterator liveouts_end() const {
return liveout_iterator(getLiveOut(getNumLiveOuts()));
}
/// Iterator range for live-outs.
iterator_range<liveout_iterator> liveouts() const {
return make_range(liveouts_begin(), liveouts_end());
}
private:
RecordAccessor(const uint8_t *P) : P(P) {}
unsigned getNumLiveOutsOffset() const {
unsigned LocOffset =
((LocationListOffset + LocationSize * getNumLocations()) + 7) & ~0x7;
return LocOffset + sizeof(uint16_t);
}
unsigned getSizeInBytes() const {
unsigned RecordSize =
getNumLiveOutsOffset() + sizeof(uint16_t) + getNumLiveOuts() * LiveOutSize;
return (RecordSize + 7) & ~0x7;
}
RecordAccessor next() const {
return RecordAccessor(P + getSizeInBytes());
}
static const unsigned PatchpointIDOffset = 0;
static const unsigned InstructionOffsetOffset =
PatchpointIDOffset + sizeof(uint64_t);
static const unsigned NumLocationsOffset =
InstructionOffsetOffset + sizeof(uint32_t) + sizeof(uint16_t);
static const unsigned LocationListOffset =
NumLocationsOffset + sizeof(uint16_t);
static const unsigned LocationSize = sizeof(uint64_t) + sizeof(uint32_t);
static const unsigned LiveOutSize = sizeof(uint32_t);
const uint8_t *P;
};
/// Construct a parser for a version-3 stackmap. StackMap data will be read
/// from the given array.
StackMapParser(ArrayRef<uint8_t> StackMapSection)
: StackMapSection(StackMapSection) {
ConstantsListOffset = FunctionListOffset + getNumFunctions() * FunctionSize;
assert(StackMapSection[0] == 3 &&
"StackMapParser can only parse version 3 stackmaps");
unsigned CurrentRecordOffset =
ConstantsListOffset + getNumConstants() * ConstantSize;
for (unsigned I = 0, E = getNumRecords(); I != E; ++I) {
StackMapRecordOffsets.push_back(CurrentRecordOffset);
CurrentRecordOffset +=
RecordAccessor(&StackMapSection[CurrentRecordOffset]).getSizeInBytes();
}
}
/// Validates the header of the specified stack map section.
static Error validateHeader(ArrayRef<uint8_t> StackMapSection) {
// See the comment for StackMaps::emitStackmapHeader().
if (StackMapSection.size() < 16)
return object::createError(
"the stack map section size (" + Twine(StackMapSection.size()) +
") is less than the minimum possible size of its header (16)");
unsigned Version = StackMapSection[0];
if (Version != 3)
return object::createError(
"the version (" + Twine(Version) +
") of the stack map section is unsupported, the "
"supported version is 3");
return Error::success();
}
using function_iterator = AccessorIterator<FunctionAccessor>;
using constant_iterator = AccessorIterator<ConstantAccessor>;
using record_iterator = AccessorIterator<RecordAccessor>;
/// Get the version number of this stackmap. (Always returns 3).
unsigned getVersion() const { return 3; }
/// Get the number of functions in the stack map.
uint32_t getNumFunctions() const {
return read<uint32_t>(&StackMapSection[NumFunctionsOffset]);
}
/// Get the number of large constants in the stack map.
uint32_t getNumConstants() const {
return read<uint32_t>(&StackMapSection[NumConstantsOffset]);
}
/// Get the number of stackmap records in the stackmap.
uint32_t getNumRecords() const {
return read<uint32_t>(&StackMapSection[NumRecordsOffset]);
}
/// Return an FunctionAccessor for the given function index.
FunctionAccessor getFunction(unsigned FunctionIndex) const {
return FunctionAccessor(StackMapSection.data() +
getFunctionOffset(FunctionIndex));
}
/// Begin iterator for functions.
function_iterator functions_begin() const {
return function_iterator(getFunction(0));
}
/// End iterator for functions.
function_iterator functions_end() const {
return function_iterator(
FunctionAccessor(StackMapSection.data() +
getFunctionOffset(getNumFunctions())));
}
/// Iterator range for functions.
iterator_range<function_iterator> functions() const {
return make_range(functions_begin(), functions_end());
}
/// Return the large constant at the given index.
ConstantAccessor getConstant(unsigned ConstantIndex) const {
return ConstantAccessor(StackMapSection.data() +
getConstantOffset(ConstantIndex));
}
/// Begin iterator for constants.
constant_iterator constants_begin() const {
return constant_iterator(getConstant(0));
}
/// End iterator for constants.
constant_iterator constants_end() const {
return constant_iterator(
ConstantAccessor(StackMapSection.data() +
getConstantOffset(getNumConstants())));
}
/// Iterator range for constants.
iterator_range<constant_iterator> constants() const {
return make_range(constants_begin(), constants_end());
}
/// Return a RecordAccessor for the given record index.
RecordAccessor getRecord(unsigned RecordIndex) const {
std::size_t RecordOffset = StackMapRecordOffsets[RecordIndex];
return RecordAccessor(StackMapSection.data() + RecordOffset);
}
/// Begin iterator for records.
record_iterator records_begin() const {
if (getNumRecords() == 0)
return record_iterator(RecordAccessor(nullptr));
return record_iterator(getRecord(0));
}
/// End iterator for records.
record_iterator records_end() const {
// Records need to be handled specially, since we cache the start addresses
// for them: We can't just compute the 1-past-the-end address, we have to
// look at the last record and use the 'next' method.
if (getNumRecords() == 0)
return record_iterator(RecordAccessor(nullptr));
return record_iterator(getRecord(getNumRecords() - 1).next());
}
/// Iterator range for records.
iterator_range<record_iterator> records() const {
return make_range(records_begin(), records_end());
}
private:
template <typename T>
static T read(const uint8_t *P) {
return support::endian::read<T, Endianness>(P);
}
static const unsigned HeaderOffset = 0;
static const unsigned NumFunctionsOffset = HeaderOffset + sizeof(uint32_t);
static const unsigned NumConstantsOffset = NumFunctionsOffset + sizeof(uint32_t);
static const unsigned NumRecordsOffset = NumConstantsOffset + sizeof(uint32_t);
static const unsigned FunctionListOffset = NumRecordsOffset + sizeof(uint32_t);
static const unsigned FunctionSize = 3 * sizeof(uint64_t);
static const unsigned ConstantSize = sizeof(uint64_t);
std::size_t getFunctionOffset(unsigned FunctionIndex) const {
return FunctionListOffset + FunctionIndex * FunctionSize;
}
std::size_t getConstantOffset(unsigned ConstantIndex) const {
return ConstantsListOffset + ConstantIndex * ConstantSize;
}
ArrayRef<uint8_t> StackMapSection;
unsigned ConstantsListOffset;
std::vector<unsigned> StackMapRecordOffsets;
};
} // end namespace llvm
#endif // LLVM_OBJECT_STACKMAPPARSER_H
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