llvm-for-llvmta/lib/Target/BPF/AsmParser/BPFAsmParser.cpp

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//===-- BPFAsmParser.cpp - Parse BPF assembly to MCInst instructions --===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/BPFMCTargetDesc.h"
#include "TargetInfo/BPFTargetInfo.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCParser/MCAsmLexer.h"
#include "llvm/MC/MCParser/MCParsedAsmOperand.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
namespace {
struct BPFOperand;
class BPFAsmParser : public MCTargetAsmParser {
SMLoc getLoc() const { return getParser().getTok().getLoc(); }
bool PreMatchCheck(OperandVector &Operands);
bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
OperandVector &Operands, MCStreamer &Out,
uint64_t &ErrorInfo,
bool MatchingInlineAsm) override;
bool ParseRegister(unsigned &RegNo, SMLoc &StartLoc, SMLoc &EndLoc) override;
OperandMatchResultTy tryParseRegister(unsigned &RegNo, SMLoc &StartLoc,
SMLoc &EndLoc) override;
bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
SMLoc NameLoc, OperandVector &Operands) override;
bool ParseDirective(AsmToken DirectiveID) override;
// "=" is used as assignment operator for assembly statment, so can't be used
// for symbol assignment.
bool equalIsAsmAssignment() override { return false; }
// "*" is used for dereferencing memory that it will be the start of
// statement.
bool starIsStartOfStatement() override { return true; }
#define GET_ASSEMBLER_HEADER
#include "BPFGenAsmMatcher.inc"
OperandMatchResultTy parseImmediate(OperandVector &Operands);
OperandMatchResultTy parseRegister(OperandVector &Operands);
OperandMatchResultTy parseOperandAsOperator(OperandVector &Operands);
public:
enum BPFMatchResultTy {
Match_Dummy = FIRST_TARGET_MATCH_RESULT_TY,
#define GET_OPERAND_DIAGNOSTIC_TYPES
#include "BPFGenAsmMatcher.inc"
#undef GET_OPERAND_DIAGNOSTIC_TYPES
};
BPFAsmParser(const MCSubtargetInfo &STI, MCAsmParser &Parser,
const MCInstrInfo &MII, const MCTargetOptions &Options)
: MCTargetAsmParser(Options, STI, MII) {
setAvailableFeatures(ComputeAvailableFeatures(STI.getFeatureBits()));
}
};
/// BPFOperand - Instances of this class represent a parsed machine
/// instruction
struct BPFOperand : public MCParsedAsmOperand {
enum KindTy {
Token,
Register,
Immediate,
} Kind;
struct RegOp {
unsigned RegNum;
};
struct ImmOp {
const MCExpr *Val;
};
SMLoc StartLoc, EndLoc;
union {
StringRef Tok;
RegOp Reg;
ImmOp Imm;
};
BPFOperand(KindTy K) : MCParsedAsmOperand(), Kind(K) {}
public:
BPFOperand(const BPFOperand &o) : MCParsedAsmOperand() {
Kind = o.Kind;
StartLoc = o.StartLoc;
EndLoc = o.EndLoc;
switch (Kind) {
case Register:
Reg = o.Reg;
break;
case Immediate:
Imm = o.Imm;
break;
case Token:
Tok = o.Tok;
break;
}
}
bool isToken() const override { return Kind == Token; }
bool isReg() const override { return Kind == Register; }
bool isImm() const override { return Kind == Immediate; }
bool isMem() const override { return false; }
bool isConstantImm() const {
return isImm() && isa<MCConstantExpr>(getImm());
}
int64_t getConstantImm() const {
const MCExpr *Val = getImm();
return static_cast<const MCConstantExpr *>(Val)->getValue();
}
bool isSImm12() const {
return (isConstantImm() && isInt<12>(getConstantImm()));
}
/// getStartLoc - Gets location of the first token of this operand
SMLoc getStartLoc() const override { return StartLoc; }
/// getEndLoc - Gets location of the last token of this operand
SMLoc getEndLoc() const override { return EndLoc; }
unsigned getReg() const override {
assert(Kind == Register && "Invalid type access!");
return Reg.RegNum;
}
const MCExpr *getImm() const {
assert(Kind == Immediate && "Invalid type access!");
return Imm.Val;
}
StringRef getToken() const {
assert(Kind == Token && "Invalid type access!");
return Tok;
}
void print(raw_ostream &OS) const override {
switch (Kind) {
case Immediate:
OS << *getImm();
break;
case Register:
OS << "<register x";
OS << getReg() << ">";
break;
case Token:
OS << "'" << getToken() << "'";
break;
}
}
void addExpr(MCInst &Inst, const MCExpr *Expr) const {
assert(Expr && "Expr shouldn't be null!");
if (auto *CE = dyn_cast<MCConstantExpr>(Expr))
Inst.addOperand(MCOperand::createImm(CE->getValue()));
else
Inst.addOperand(MCOperand::createExpr(Expr));
}
// Used by the TableGen Code
void addRegOperands(MCInst &Inst, unsigned N) const {
assert(N == 1 && "Invalid number of operands!");
Inst.addOperand(MCOperand::createReg(getReg()));
}
void addImmOperands(MCInst &Inst, unsigned N) const {
assert(N == 1 && "Invalid number of operands!");
addExpr(Inst, getImm());
}
static std::unique_ptr<BPFOperand> createToken(StringRef Str, SMLoc S) {
auto Op = std::make_unique<BPFOperand>(Token);
Op->Tok = Str;
Op->StartLoc = S;
Op->EndLoc = S;
return Op;
}
static std::unique_ptr<BPFOperand> createReg(unsigned RegNo, SMLoc S,
SMLoc E) {
auto Op = std::make_unique<BPFOperand>(Register);
Op->Reg.RegNum = RegNo;
Op->StartLoc = S;
Op->EndLoc = E;
return Op;
}
static std::unique_ptr<BPFOperand> createImm(const MCExpr *Val, SMLoc S,
SMLoc E) {
auto Op = std::make_unique<BPFOperand>(Immediate);
Op->Imm.Val = Val;
Op->StartLoc = S;
Op->EndLoc = E;
return Op;
}
// Identifiers that can be used at the start of a statment.
static bool isValidIdAtStart(StringRef Name) {
return StringSwitch<bool>(Name.lower())
.Case("if", true)
.Case("call", true)
.Case("goto", true)
.Case("*", true)
.Case("exit", true)
.Case("lock", true)
.Case("ld_pseudo", true)
.Default(false);
}
// Identifiers that can be used in the middle of a statment.
static bool isValidIdInMiddle(StringRef Name) {
return StringSwitch<bool>(Name.lower())
.Case("u64", true)
.Case("u32", true)
.Case("u16", true)
.Case("u8", true)
.Case("be64", true)
.Case("be32", true)
.Case("be16", true)
.Case("le64", true)
.Case("le32", true)
.Case("le16", true)
.Case("goto", true)
.Case("ll", true)
.Case("skb", true)
.Case("s", true)
.Default(false);
}
};
} // end anonymous namespace.
#define GET_REGISTER_MATCHER
#define GET_MATCHER_IMPLEMENTATION
#include "BPFGenAsmMatcher.inc"
bool BPFAsmParser::PreMatchCheck(OperandVector &Operands) {
if (Operands.size() == 4) {
// check "reg1 = -reg2" and "reg1 = be16/be32/be64/le16/le32/le64 reg2",
// reg1 must be the same as reg2
BPFOperand &Op0 = (BPFOperand &)*Operands[0];
BPFOperand &Op1 = (BPFOperand &)*Operands[1];
BPFOperand &Op2 = (BPFOperand &)*Operands[2];
BPFOperand &Op3 = (BPFOperand &)*Operands[3];
if (Op0.isReg() && Op1.isToken() && Op2.isToken() && Op3.isReg()
&& Op1.getToken() == "="
&& (Op2.getToken() == "-" || Op2.getToken() == "be16"
|| Op2.getToken() == "be32" || Op2.getToken() == "be64"
|| Op2.getToken() == "le16" || Op2.getToken() == "le32"
|| Op2.getToken() == "le64")
&& Op0.getReg() != Op3.getReg())
return true;
}
return false;
}
bool BPFAsmParser::MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
OperandVector &Operands,
MCStreamer &Out, uint64_t &ErrorInfo,
bool MatchingInlineAsm) {
MCInst Inst;
SMLoc ErrorLoc;
if (PreMatchCheck(Operands))
return Error(IDLoc, "additional inst constraint not met");
switch (MatchInstructionImpl(Operands, Inst, ErrorInfo, MatchingInlineAsm)) {
default:
break;
case Match_Success:
Inst.setLoc(IDLoc);
Out.emitInstruction(Inst, getSTI());
return false;
case Match_MissingFeature:
return Error(IDLoc, "instruction use requires an option to be enabled");
case Match_MnemonicFail:
return Error(IDLoc, "unrecognized instruction mnemonic");
case Match_InvalidOperand:
ErrorLoc = IDLoc;
if (ErrorInfo != ~0U) {
if (ErrorInfo >= Operands.size())
return Error(ErrorLoc, "too few operands for instruction");
ErrorLoc = ((BPFOperand &)*Operands[ErrorInfo]).getStartLoc();
if (ErrorLoc == SMLoc())
ErrorLoc = IDLoc;
}
return Error(ErrorLoc, "invalid operand for instruction");
}
llvm_unreachable("Unknown match type detected!");
}
bool BPFAsmParser::ParseRegister(unsigned &RegNo, SMLoc &StartLoc,
SMLoc &EndLoc) {
if (tryParseRegister(RegNo, StartLoc, EndLoc) != MatchOperand_Success)
return Error(StartLoc, "invalid register name");
return false;
}
OperandMatchResultTy BPFAsmParser::tryParseRegister(unsigned &RegNo,
SMLoc &StartLoc,
SMLoc &EndLoc) {
const AsmToken &Tok = getParser().getTok();
StartLoc = Tok.getLoc();
EndLoc = Tok.getEndLoc();
RegNo = 0;
StringRef Name = getLexer().getTok().getIdentifier();
if (!MatchRegisterName(Name)) {
getParser().Lex(); // Eat identifier token.
return MatchOperand_Success;
}
return MatchOperand_NoMatch;
}
OperandMatchResultTy
BPFAsmParser::parseOperandAsOperator(OperandVector &Operands) {
SMLoc S = getLoc();
if (getLexer().getKind() == AsmToken::Identifier) {
StringRef Name = getLexer().getTok().getIdentifier();
if (BPFOperand::isValidIdInMiddle(Name)) {
getLexer().Lex();
Operands.push_back(BPFOperand::createToken(Name, S));
return MatchOperand_Success;
}
return MatchOperand_NoMatch;
}
switch (getLexer().getKind()) {
case AsmToken::Minus:
case AsmToken::Plus: {
if (getLexer().peekTok().is(AsmToken::Integer))
return MatchOperand_NoMatch;
LLVM_FALLTHROUGH;
}
case AsmToken::Equal:
case AsmToken::Greater:
case AsmToken::Less:
case AsmToken::Pipe:
case AsmToken::Star:
case AsmToken::LParen:
case AsmToken::RParen:
case AsmToken::LBrac:
case AsmToken::RBrac:
case AsmToken::Slash:
case AsmToken::Amp:
case AsmToken::Percent:
case AsmToken::Caret: {
StringRef Name = getLexer().getTok().getString();
getLexer().Lex();
Operands.push_back(BPFOperand::createToken(Name, S));
return MatchOperand_Success;
}
case AsmToken::EqualEqual:
case AsmToken::ExclaimEqual:
case AsmToken::GreaterEqual:
case AsmToken::GreaterGreater:
case AsmToken::LessEqual:
case AsmToken::LessLess: {
Operands.push_back(BPFOperand::createToken(
getLexer().getTok().getString().substr(0, 1), S));
Operands.push_back(BPFOperand::createToken(
getLexer().getTok().getString().substr(1, 1), S));
getLexer().Lex();
return MatchOperand_Success;
}
default:
break;
}
return MatchOperand_NoMatch;
}
OperandMatchResultTy BPFAsmParser::parseRegister(OperandVector &Operands) {
SMLoc S = getLoc();
SMLoc E = SMLoc::getFromPointer(S.getPointer() - 1);
switch (getLexer().getKind()) {
default:
return MatchOperand_NoMatch;
case AsmToken::Identifier:
StringRef Name = getLexer().getTok().getIdentifier();
unsigned RegNo = MatchRegisterName(Name);
if (RegNo == 0)
return MatchOperand_NoMatch;
getLexer().Lex();
Operands.push_back(BPFOperand::createReg(RegNo, S, E));
}
return MatchOperand_Success;
}
OperandMatchResultTy BPFAsmParser::parseImmediate(OperandVector &Operands) {
switch (getLexer().getKind()) {
default:
return MatchOperand_NoMatch;
case AsmToken::LParen:
case AsmToken::Minus:
case AsmToken::Plus:
case AsmToken::Integer:
case AsmToken::String:
case AsmToken::Identifier:
break;
}
const MCExpr *IdVal;
SMLoc S = getLoc();
if (getParser().parseExpression(IdVal))
return MatchOperand_ParseFail;
SMLoc E = SMLoc::getFromPointer(S.getPointer() - 1);
Operands.push_back(BPFOperand::createImm(IdVal, S, E));
return MatchOperand_Success;
}
/// ParseInstruction - Parse an BPF instruction which is in BPF verifier
/// format.
bool BPFAsmParser::ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
SMLoc NameLoc, OperandVector &Operands) {
// The first operand could be either register or actually an operator.
unsigned RegNo = MatchRegisterName(Name);
if (RegNo != 0) {
SMLoc E = SMLoc::getFromPointer(NameLoc.getPointer() - 1);
Operands.push_back(BPFOperand::createReg(RegNo, NameLoc, E));
} else if (BPFOperand::isValidIdAtStart (Name))
Operands.push_back(BPFOperand::createToken(Name, NameLoc));
else
return Error(NameLoc, "invalid register/token name");
while (!getLexer().is(AsmToken::EndOfStatement)) {
// Attempt to parse token as operator
if (parseOperandAsOperator(Operands) == MatchOperand_Success)
continue;
// Attempt to parse token as register
if (parseRegister(Operands) == MatchOperand_Success)
continue;
// Attempt to parse token as an immediate
if (parseImmediate(Operands) != MatchOperand_Success) {
SMLoc Loc = getLexer().getLoc();
return Error(Loc, "unexpected token");
}
}
if (getLexer().isNot(AsmToken::EndOfStatement)) {
SMLoc Loc = getLexer().getLoc();
getParser().eatToEndOfStatement();
return Error(Loc, "unexpected token");
}
// Consume the EndOfStatement.
getParser().Lex();
return false;
}
bool BPFAsmParser::ParseDirective(AsmToken DirectiveID) { return true; }
extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFAsmParser() {
RegisterMCAsmParser<BPFAsmParser> X(getTheBPFTarget());
RegisterMCAsmParser<BPFAsmParser> Y(getTheBPFleTarget());
RegisterMCAsmParser<BPFAsmParser> Z(getTheBPFbeTarget());
}