//===- StackMaps.h - StackMaps ----------------------------------*- 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_CODEGEN_STACKMAPS_H
#define LLVM_CODEGEN_STACKMAPS_H
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/Support/Debug.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <vector>
namespace llvm {
class AsmPrinter;
class MCSymbol;
class MCExpr;
class MCStreamer;
class raw_ostream;
class TargetRegisterInfo;
/// MI-level stackmap operands.
///
/// MI stackmap operations take the form:
/// <id>, <numBytes>, live args...
class StackMapOpers {
public:
/// Enumerate the meta operands.
enum { IDPos, NBytesPos };
private:
const MachineInstr* MI;
public:
explicit StackMapOpers(const MachineInstr *MI);
/// Return the ID for the given stackmap
uint64_t getID() const { return MI->getOperand(IDPos).getImm(); }
/// Return the number of patchable bytes the given stackmap should emit.
uint32_t getNumPatchBytes() const {
return MI->getOperand(NBytesPos).getImm();
}
/// Get the operand index of the variable list of non-argument operands.
/// These hold the "live state".
unsigned getVarIdx() const {
// Skip ID, nShadowBytes.
return 2;
}
};
/// MI-level patchpoint operands.
///
/// MI patchpoint operations take the form:
/// [<def>], <id>, <numBytes>, <target>, <numArgs>, <cc>, ...
///
/// IR patchpoint intrinsics do not have the <cc> operand because calling
/// convention is part of the subclass data.
///
/// SD patchpoint nodes do not have a def operand because it is part of the
/// SDValue.
///
/// Patchpoints following the anyregcc convention are handled specially. For
/// these, the stack map also records the location of the return value and
/// arguments.
class PatchPointOpers {
public:
/// Enumerate the meta operands.
enum { IDPos, NBytesPos, TargetPos, NArgPos, CCPos, MetaEnd };
private:
const MachineInstr *MI;
bool HasDef;
unsigned getMetaIdx(unsigned Pos = 0) const {
assert(Pos < MetaEnd && "Meta operand index out of range.");
return (HasDef ? 1 : 0) + Pos;
}
const MachineOperand &getMetaOper(unsigned Pos) const {
return MI->getOperand(getMetaIdx(Pos));
}
public:
explicit PatchPointOpers(const MachineInstr *MI);
bool isAnyReg() const { return (getCallingConv() == CallingConv::AnyReg); }
bool hasDef() const { return HasDef; }
/// Return the ID for the given patchpoint.
uint64_t getID() const { return getMetaOper(IDPos).getImm(); }
/// Return the number of patchable bytes the given patchpoint should emit.
uint32_t getNumPatchBytes() const {
return getMetaOper(NBytesPos).getImm();
}
/// Returns the target of the underlying call.
const MachineOperand &getCallTarget() const {
return getMetaOper(TargetPos);
}
/// Returns the calling convention
CallingConv::ID getCallingConv() const {
return getMetaOper(CCPos).getImm();
}
unsigned getArgIdx() const { return getMetaIdx() + MetaEnd; }
/// Return the number of call arguments
uint32_t getNumCallArgs() const {
return MI->getOperand(getMetaIdx(NArgPos)).getImm();
}
/// Get the operand index of the variable list of non-argument operands.
/// These hold the "live state".
unsigned getVarIdx() const {
return getMetaIdx() + MetaEnd + getNumCallArgs();
}
/// Get the index at which stack map locations will be recorded.
/// Arguments are not recorded unless the anyregcc convention is used.
unsigned getStackMapStartIdx() const {
if (isAnyReg())
return getArgIdx();
return getVarIdx();
}
/// Get the next scratch register operand index.
unsigned getNextScratchIdx(unsigned StartIdx = 0) const;
};
/// MI-level Statepoint operands
///
/// Statepoint operands take the form:
/// <id>, <num patch bytes >, <num call arguments>, <call target>,
/// [call arguments...],
/// <StackMaps::ConstantOp>, <calling convention>,
/// <StackMaps::ConstantOp>, <statepoint flags>,
/// <StackMaps::ConstantOp>, <num deopt args>, [deopt args...],
/// <StackMaps::ConstantOp>, <num gc pointer args>, [gc pointer args...],
/// <StackMaps::ConstantOp>, <num gc allocas>, [gc allocas args...],
/// <StackMaps::ConstantOp>, <num entries in gc map>, [base/derived pairs]
/// base/derived pairs in gc map are logical indices into <gc pointer args>
/// section.
/// All gc pointers assigned to VRegs produce new value (in form of MI Def
/// operand) and are tied to it.
class StatepointOpers {
// TODO:: we should change the STATEPOINT representation so that CC and
// Flags should be part of meta operands, with args and deopt operands, and
// gc operands all prefixed by their length and a type code. This would be
// much more consistent.
// These values are absolute offsets into the operands of the statepoint
// instruction.
enum { IDPos, NBytesPos, NCallArgsPos, CallTargetPos, MetaEnd };
// These values are relative offsets from the start of the statepoint meta
// arguments (i.e. the end of the call arguments).
enum { CCOffset = 1, FlagsOffset = 3, NumDeoptOperandsOffset = 5 };
public:
explicit StatepointOpers(const MachineInstr *MI) : MI(MI) {
NumDefs = MI->getNumDefs();
}
/// Get index of statepoint ID operand.
unsigned getIDPos() const { return NumDefs + IDPos; }
/// Get index of Num Patch Bytes operand.
unsigned getNBytesPos() const { return NumDefs + NBytesPos; }
/// Get index of Num Call Arguments operand.
unsigned getNCallArgsPos() const { return NumDefs + NCallArgsPos; }
/// Get starting index of non call related arguments
/// (calling convention, statepoint flags, vm state and gc state).
unsigned getVarIdx() const {
return MI->getOperand(NumDefs + NCallArgsPos).getImm() + MetaEnd + NumDefs;
}
/// Get index of Calling Convention operand.
unsigned getCCIdx() const { return getVarIdx() + CCOffset; }
/// Get index of Flags operand.
unsigned getFlagsIdx() const { return getVarIdx() + FlagsOffset; }
/// Get index of Number Deopt Arguments operand.
unsigned getNumDeoptArgsIdx() const {
return getVarIdx() + NumDeoptOperandsOffset;
}
/// Return the ID for the given statepoint.
uint64_t getID() const { return MI->getOperand(NumDefs + IDPos).getImm(); }
/// Return the number of patchable bytes the given statepoint should emit.
uint32_t getNumPatchBytes() const {
return MI->getOperand(NumDefs + NBytesPos).getImm();
}
/// Return the target of the underlying call.
const MachineOperand &getCallTarget() const {
return MI->getOperand(NumDefs + CallTargetPos);
}
/// Return the calling convention.
CallingConv::ID getCallingConv() const {
return MI->getOperand(getCCIdx()).getImm();
}
/// Return the statepoint flags.
uint64_t getFlags() const { return MI->getOperand(getFlagsIdx()).getImm(); }
uint64_t getNumDeoptArgs() const {
return MI->getOperand(getNumDeoptArgsIdx()).getImm();
}
/// Get index of number of gc map entries.
unsigned getNumGcMapEntriesIdx();
/// Get index of number of gc allocas.
unsigned getNumAllocaIdx();
/// Get index of number of GC pointers.
unsigned getNumGCPtrIdx();
/// Get index of first GC pointer operand of -1 if there are none.
int getFirstGCPtrIdx();
/// Get vector of base/derived pairs from statepoint.
/// Elements are indices into GC Pointer operand list (logical).
/// Returns number of elements in GCMap.
unsigned
getGCPointerMap(SmallVectorImpl<std::pair<unsigned, unsigned>> &GCMap);
/// Return true if Reg is used only in operands which can be folded to
/// stack usage.
bool isFoldableReg(Register Reg) const;
/// Return true if Reg is used only in operands of MI which can be folded to
/// stack usage and MI is a statepoint instruction.
static bool isFoldableReg(const MachineInstr *MI, Register Reg);
private:
const MachineInstr *MI;
unsigned NumDefs;
};
class StackMaps {
public:
struct Location {
enum LocationType {
Unprocessed,
Register,
Direct,
Indirect,
Constant,
ConstantIndex
};
LocationType Type = Unprocessed;
unsigned Size = 0;
unsigned Reg = 0;
int64_t Offset = 0;
Location() = default;
Location(LocationType Type, unsigned Size, unsigned Reg, int64_t Offset)
: Type(Type), Size(Size), Reg(Reg), Offset(Offset) {}
};
struct LiveOutReg {
unsigned short Reg = 0;
unsigned short DwarfRegNum = 0;
unsigned short Size = 0;
LiveOutReg() = default;
LiveOutReg(unsigned short Reg, unsigned short DwarfRegNum,
unsigned short Size)
: Reg(Reg), DwarfRegNum(DwarfRegNum), Size(Size) {}
};
// OpTypes are used to encode information about the following logical
// operand (which may consist of several MachineOperands) for the
// OpParser.
using OpType = enum { DirectMemRefOp, IndirectMemRefOp, ConstantOp };
StackMaps(AsmPrinter &AP);
/// Get index of next meta operand.
/// Similar to parseOperand, but does not actually parses operand meaning.
static unsigned getNextMetaArgIdx(const MachineInstr *MI, unsigned CurIdx);
void reset() {
CSInfos.clear();
ConstPool.clear();
FnInfos.clear();
}
using LocationVec = SmallVector<Location, 8>;
using LiveOutVec = SmallVector<LiveOutReg, 8>;
using ConstantPool = MapVector<uint64_t, uint64_t>;
struct FunctionInfo {
uint64_t StackSize = 0;
uint64_t RecordCount = 1;
FunctionInfo() = default;
explicit FunctionInfo(uint64_t StackSize) : StackSize(StackSize) {}
};
struct CallsiteInfo {
const MCExpr *CSOffsetExpr = nullptr;
uint64_t ID = 0;
LocationVec Locations;
LiveOutVec LiveOuts;
CallsiteInfo() = default;
CallsiteInfo(const MCExpr *CSOffsetExpr, uint64_t ID,
LocationVec &&Locations, LiveOutVec &&LiveOuts)
: CSOffsetExpr(CSOffsetExpr), ID(ID), Locations(std::move(Locations)),
LiveOuts(std::move(LiveOuts)) {}
};
using FnInfoMap = MapVector<const MCSymbol *, FunctionInfo>;
using CallsiteInfoList = std::vector<CallsiteInfo>;
/// Generate a stackmap record for a stackmap instruction.
///
/// MI must be a raw STACKMAP, not a PATCHPOINT.
void recordStackMap(const MCSymbol &L,
const MachineInstr &MI);
/// Generate a stackmap record for a patchpoint instruction.
void recordPatchPoint(const MCSymbol &L,
const MachineInstr &MI);
/// Generate a stackmap record for a statepoint instruction.
void recordStatepoint(const MCSymbol &L,
const MachineInstr &MI);
/// If there is any stack map data, create a stack map section and serialize
/// the map info into it. This clears the stack map data structures
/// afterwards.
void serializeToStackMapSection();
/// Get call site info.
CallsiteInfoList &getCSInfos() { return CSInfos; }
/// Get function info.
FnInfoMap &getFnInfos() { return FnInfos; }
private:
static const char *WSMP;
AsmPrinter &AP;
CallsiteInfoList CSInfos;
ConstantPool ConstPool;
FnInfoMap FnInfos;
MachineInstr::const_mop_iterator
parseOperand(MachineInstr::const_mop_iterator MOI,
MachineInstr::const_mop_iterator MOE, LocationVec &Locs,
LiveOutVec &LiveOuts) const;
/// Specialized parser of statepoint operands.
/// They do not directly correspond to StackMap record entries.
void parseStatepointOpers(const MachineInstr &MI,
MachineInstr::const_mop_iterator MOI,
MachineInstr::const_mop_iterator MOE,
LocationVec &Locations, LiveOutVec &LiveOuts);
/// Create a live-out register record for the given register @p Reg.
LiveOutReg createLiveOutReg(unsigned Reg,
const TargetRegisterInfo *TRI) const;
/// Parse the register live-out mask and return a vector of live-out
/// registers that need to be recorded in the stackmap.
LiveOutVec parseRegisterLiveOutMask(const uint32_t *Mask) const;
/// Record the locations of the operands of the provided instruction in a
/// record keyed by the provided label. For instructions w/AnyReg calling
/// convention the return register is also recorded if requested. For
/// STACKMAP, and PATCHPOINT the label is expected to immediately *preceed*
/// lowering of the MI to MCInsts. For STATEPOINT, it expected to
/// immediately *follow*. It's not clear this difference was intentional,
/// but it exists today.
void recordStackMapOpers(const MCSymbol &L,
const MachineInstr &MI, uint64_t ID,
MachineInstr::const_mop_iterator MOI,
MachineInstr::const_mop_iterator MOE,
bool recordResult = false);
/// Emit the stackmap header.
void emitStackmapHeader(MCStreamer &OS);
/// Emit the function frame record for each function.
void emitFunctionFrameRecords(MCStreamer &OS);
/// Emit the constant pool.
void emitConstantPoolEntries(MCStreamer &OS);
/// Emit the callsite info for each stackmap/patchpoint intrinsic call.
void emitCallsiteEntries(MCStreamer &OS);
void print(raw_ostream &OS);
void debug() { print(dbgs()); }
};
} // end namespace llvm
#endif // LLVM_CODEGEN_STACKMAPS_H