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llvm-for-llvmta/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp

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//==- WebAssemblyAsmParser.cpp - Assembler for WebAssembly -*- 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file is part of the WebAssembly Assembler.
///
/// It contains code to translate a parsed .s file into MCInsts.
///
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "MCTargetDesc/WebAssemblyTargetStreamer.h"
#include "TargetInfo/WebAssemblyTargetInfo.h"
#include "WebAssembly.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCParser/MCParsedAsmOperand.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCSectionWasm.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCSymbolWasm.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
#define DEBUG_TYPE "wasm-asm-parser"
static const char *getSubtargetFeatureName(uint64_t Val);
namespace {
/// WebAssemblyOperand - Instances of this class represent the operands in a
/// parsed Wasm machine instruction.
struct WebAssemblyOperand : public MCParsedAsmOperand {
enum KindTy { Token, Integer, Float, Symbol, BrList } Kind;
SMLoc StartLoc, EndLoc;
struct TokOp {
StringRef Tok;
};
struct IntOp {
int64_t Val;
};
struct FltOp {
double Val;
};
struct SymOp {
const MCExpr *Exp;
};
struct BrLOp {
std::vector<unsigned> List;
};
union {
struct TokOp Tok;
struct IntOp Int;
struct FltOp Flt;
struct SymOp Sym;
struct BrLOp BrL;
};
WebAssemblyOperand(KindTy K, SMLoc Start, SMLoc End, TokOp T)
: Kind(K), StartLoc(Start), EndLoc(End), Tok(T) {}
WebAssemblyOperand(KindTy K, SMLoc Start, SMLoc End, IntOp I)
: Kind(K), StartLoc(Start), EndLoc(End), Int(I) {}
WebAssemblyOperand(KindTy K, SMLoc Start, SMLoc End, FltOp F)
: Kind(K), StartLoc(Start), EndLoc(End), Flt(F) {}
WebAssemblyOperand(KindTy K, SMLoc Start, SMLoc End, SymOp S)
: Kind(K), StartLoc(Start), EndLoc(End), Sym(S) {}
WebAssemblyOperand(KindTy K, SMLoc Start, SMLoc End)
: Kind(K), StartLoc(Start), EndLoc(End), BrL() {}
~WebAssemblyOperand() {
if (isBrList())
BrL.~BrLOp();
}
bool isToken() const override { return Kind == Token; }
bool isImm() const override { return Kind == Integer || Kind == Symbol; }
bool isFPImm() const { return Kind == Float; }
bool isMem() const override { return false; }
bool isReg() const override { return false; }
bool isBrList() const { return Kind == BrList; }
unsigned getReg() const override {
llvm_unreachable("Assembly inspects a register operand");
return 0;
}
StringRef getToken() const {
assert(isToken());
return Tok.Tok;
}
SMLoc getStartLoc() const override { return StartLoc; }
SMLoc getEndLoc() const override { return EndLoc; }
void addRegOperands(MCInst &, unsigned) const {
// Required by the assembly matcher.
llvm_unreachable("Assembly matcher creates register operands");
}
void addImmOperands(MCInst &Inst, unsigned N) const {
assert(N == 1 && "Invalid number of operands!");
if (Kind == Integer)
Inst.addOperand(MCOperand::createImm(Int.Val));
else if (Kind == Symbol)
Inst.addOperand(MCOperand::createExpr(Sym.Exp));
else
llvm_unreachable("Should be integer immediate or symbol!");
}
void addFPImmOperands(MCInst &Inst, unsigned N) const {
assert(N == 1 && "Invalid number of operands!");
if (Kind == Float)
Inst.addOperand(MCOperand::createFPImm(Flt.Val));
else
llvm_unreachable("Should be float immediate!");
}
void addBrListOperands(MCInst &Inst, unsigned N) const {
assert(N == 1 && isBrList() && "Invalid BrList!");
for (auto Br : BrL.List)
Inst.addOperand(MCOperand::createImm(Br));
}
void print(raw_ostream &OS) const override {
switch (Kind) {
case Token:
OS << "Tok:" << Tok.Tok;
break;
case Integer:
OS << "Int:" << Int.Val;
break;
case Float:
OS << "Flt:" << Flt.Val;
break;
case Symbol:
OS << "Sym:" << Sym.Exp;
break;
case BrList:
OS << "BrList:" << BrL.List.size();
break;
}
}
};
static MCSymbolWasm *GetOrCreateFunctionTableSymbol(MCContext &Ctx,
const StringRef &Name) {
// FIXME: Duplicates functionality from
// MC/WasmObjectWriter::recordRelocation, as well as WebAssemblyCodegen's
// WebAssembly:getOrCreateFunctionTableSymbol.
MCSymbolWasm *Sym = cast_or_null<MCSymbolWasm>(Ctx.lookupSymbol(Name));
if (Sym) {
if (!Sym->isFunctionTable())
Ctx.reportError(SMLoc(), "symbol is not a wasm funcref table");
} else {
Sym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(Name));
Sym->setFunctionTable();
// The default function table is synthesized by the linker.
Sym->setUndefined();
}
return Sym;
}
class WebAssemblyAsmParser final : public MCTargetAsmParser {
MCAsmParser &Parser;
MCAsmLexer &Lexer;
// Much like WebAssemblyAsmPrinter in the backend, we have to own these.
std::vector<std::unique_ptr<wasm::WasmSignature>> Signatures;
std::vector<std::unique_ptr<std::string>> Names;
// Order of labels, directives and instructions in a .s file have no
// syntactical enforcement. This class is a callback from the actual parser,
// and yet we have to be feeding data to the streamer in a very particular
// order to ensure a correct binary encoding that matches the regular backend
// (the streamer does not enforce this). This "state machine" enum helps
// guarantee that correct order.
enum ParserState {
FileStart,
Label,
FunctionStart,
FunctionLocals,
Instructions,
EndFunction,
DataSection,
} CurrentState = FileStart;
// For ensuring blocks are properly nested.
enum NestingType {
Function,
Block,
Loop,
Try,
If,
Else,
Undefined,
};
std::vector<NestingType> NestingStack;
// We track this to see if a .functype following a label is the same,
// as this is how we recognize the start of a function.
MCSymbol *LastLabel = nullptr;
MCSymbol *LastFunctionLabel = nullptr;
public:
WebAssemblyAsmParser(const MCSubtargetInfo &STI, MCAsmParser &Parser,
const MCInstrInfo &MII, const MCTargetOptions &Options)
: MCTargetAsmParser(Options, STI, MII), Parser(Parser),
Lexer(Parser.getLexer()) {
setAvailableFeatures(ComputeAvailableFeatures(STI.getFeatureBits()));
}
#define GET_ASSEMBLER_HEADER
#include "WebAssemblyGenAsmMatcher.inc"
// TODO: This is required to be implemented, but appears unused.
bool ParseRegister(unsigned & /*RegNo*/, SMLoc & /*StartLoc*/,
SMLoc & /*EndLoc*/) override {
llvm_unreachable("ParseRegister is not implemented.");
}
OperandMatchResultTy tryParseRegister(unsigned & /*RegNo*/,
SMLoc & /*StartLoc*/,
SMLoc & /*EndLoc*/) override {
llvm_unreachable("tryParseRegister is not implemented.");
}
bool error(const Twine &Msg, const AsmToken &Tok) {
return Parser.Error(Tok.getLoc(), Msg + Tok.getString());
}
bool error(const Twine &Msg) {
return Parser.Error(Lexer.getTok().getLoc(), Msg);
}
void addSignature(std::unique_ptr<wasm::WasmSignature> &&Sig) {
Signatures.push_back(std::move(Sig));
}
StringRef storeName(StringRef Name) {
std::unique_ptr<std::string> N = std::make_unique<std::string>(Name);
Names.push_back(std::move(N));
return *Names.back();
}
std::pair<StringRef, StringRef> nestingString(NestingType NT) {
switch (NT) {
case Function:
return {"function", "end_function"};
case Block:
return {"block", "end_block"};
case Loop:
return {"loop", "end_loop"};
case Try:
return {"try", "end_try"};
case If:
return {"if", "end_if"};
case Else:
return {"else", "end_if"};
default:
llvm_unreachable("unknown NestingType");
}
}
void push(NestingType NT) { NestingStack.push_back(NT); }
bool pop(StringRef Ins, NestingType NT1, NestingType NT2 = Undefined) {
if (NestingStack.empty())
return error(Twine("End of block construct with no start: ") + Ins);
auto Top = NestingStack.back();
if (Top != NT1 && Top != NT2)
return error(Twine("Block construct type mismatch, expected: ") +
nestingString(Top).second + ", instead got: " + Ins);
NestingStack.pop_back();
return false;
}
bool ensureEmptyNestingStack() {
auto Err = !NestingStack.empty();
while (!NestingStack.empty()) {
error(Twine("Unmatched block construct(s) at function end: ") +
nestingString(NestingStack.back()).first);
NestingStack.pop_back();
}
return Err;
}
bool isNext(AsmToken::TokenKind Kind) {
auto Ok = Lexer.is(Kind);
if (Ok)
Parser.Lex();
return Ok;
}
bool expect(AsmToken::TokenKind Kind, const char *KindName) {
if (!isNext(Kind))
return error(std::string("Expected ") + KindName + ", instead got: ",
Lexer.getTok());
return false;
}
StringRef expectIdent() {
if (!Lexer.is(AsmToken::Identifier)) {
error("Expected identifier, got: ", Lexer.getTok());
return StringRef();
}
auto Name = Lexer.getTok().getString();
Parser.Lex();
return Name;
}
Optional<wasm::ValType> parseType(const StringRef &Type) {
// FIXME: can't use StringSwitch because wasm::ValType doesn't have a
// "invalid" value.
if (Type == "i32")
return wasm::ValType::I32;
if (Type == "i64")
return wasm::ValType::I64;
if (Type == "f32")
return wasm::ValType::F32;
if (Type == "f64")
return wasm::ValType::F64;
if (Type == "v128" || Type == "i8x16" || Type == "i16x8" ||
Type == "i32x4" || Type == "i64x2" || Type == "f32x4" ||
Type == "f64x2")
return wasm::ValType::V128;
if (Type == "funcref")
return wasm::ValType::FUNCREF;
if (Type == "externref")
return wasm::ValType::EXTERNREF;
return Optional<wasm::ValType>();
}
WebAssembly::BlockType parseBlockType(StringRef ID) {
// Multivalue block types are handled separately in parseSignature
return StringSwitch<WebAssembly::BlockType>(ID)
.Case("i32", WebAssembly::BlockType::I32)
.Case("i64", WebAssembly::BlockType::I64)
.Case("f32", WebAssembly::BlockType::F32)
.Case("f64", WebAssembly::BlockType::F64)
.Case("v128", WebAssembly::BlockType::V128)
.Case("funcref", WebAssembly::BlockType::Funcref)
.Case("externref", WebAssembly::BlockType::Externref)
.Case("void", WebAssembly::BlockType::Void)
.Default(WebAssembly::BlockType::Invalid);
}
bool parseRegTypeList(SmallVectorImpl<wasm::ValType> &Types) {
while (Lexer.is(AsmToken::Identifier)) {
auto Type = parseType(Lexer.getTok().getString());
if (!Type)
return error("unknown type: ", Lexer.getTok());
Types.push_back(Type.getValue());
Parser.Lex();
if (!isNext(AsmToken::Comma))
break;
}
return false;
}
void parseSingleInteger(bool IsNegative, OperandVector &Operands) {
auto &Int = Lexer.getTok();
int64_t Val = Int.getIntVal();
if (IsNegative)
Val = -Val;
Operands.push_back(std::make_unique<WebAssemblyOperand>(
WebAssemblyOperand::Integer, Int.getLoc(), Int.getEndLoc(),
WebAssemblyOperand::IntOp{Val}));
Parser.Lex();
}
bool parseSingleFloat(bool IsNegative, OperandVector &Operands) {
auto &Flt = Lexer.getTok();
double Val;
if (Flt.getString().getAsDouble(Val, false))
return error("Cannot parse real: ", Flt);
if (IsNegative)
Val = -Val;
Operands.push_back(std::make_unique<WebAssemblyOperand>(
WebAssemblyOperand::Float, Flt.getLoc(), Flt.getEndLoc(),
WebAssemblyOperand::FltOp{Val}));
Parser.Lex();
return false;
}
bool parseSpecialFloatMaybe(bool IsNegative, OperandVector &Operands) {
if (Lexer.isNot(AsmToken::Identifier))
return true;
auto &Flt = Lexer.getTok();
auto S = Flt.getString();
double Val;
if (S.compare_lower("infinity") == 0) {
Val = std::numeric_limits<double>::infinity();
} else if (S.compare_lower("nan") == 0) {
Val = std::numeric_limits<double>::quiet_NaN();
} else {
return true;
}
if (IsNegative)
Val = -Val;
Operands.push_back(std::make_unique<WebAssemblyOperand>(
WebAssemblyOperand::Float, Flt.getLoc(), Flt.getEndLoc(),
WebAssemblyOperand::FltOp{Val}));
Parser.Lex();
return false;
}
bool checkForP2AlignIfLoadStore(OperandVector &Operands, StringRef InstName) {
// FIXME: there is probably a cleaner way to do this.
auto IsLoadStore = InstName.find(".load") != StringRef::npos ||
InstName.find(".store") != StringRef::npos ||
InstName.find("prefetch") != StringRef::npos;
auto IsAtomic = InstName.find("atomic.") != StringRef::npos;
if (IsLoadStore || IsAtomic) {
// Parse load/store operands of the form: offset:p2align=align
if (IsLoadStore && isNext(AsmToken::Colon)) {
auto Id = expectIdent();
if (Id != "p2align")
return error("Expected p2align, instead got: " + Id);
if (expect(AsmToken::Equal, "="))
return true;
if (!Lexer.is(AsmToken::Integer))
return error("Expected integer constant");
parseSingleInteger(false, Operands);
} else {
// v128.{load,store}{8,16,32,64}_lane has both a memarg and a lane
// index. We need to avoid parsing an extra alignment operand for the
// lane index.
auto IsLoadStoreLane = InstName.find("_lane") != StringRef::npos;
if (IsLoadStoreLane && Operands.size() == 4)
return false;
// Alignment not specified (or atomics, must use default alignment).
// We can't just call WebAssembly::GetDefaultP2Align since we don't have
// an opcode until after the assembly matcher, so set a default to fix
// up later.
auto Tok = Lexer.getTok();
Operands.push_back(std::make_unique<WebAssemblyOperand>(
WebAssemblyOperand::Integer, Tok.getLoc(), Tok.getEndLoc(),
WebAssemblyOperand::IntOp{-1}));
}
}
return false;
}
WebAssembly::HeapType parseHeapType(StringRef Id) {
return StringSwitch<WebAssembly::HeapType>(Id)
.Case("extern", WebAssembly::HeapType::Externref)
.Case("func", WebAssembly::HeapType::Funcref)
.Default(WebAssembly::HeapType::Invalid);
}
void addBlockTypeOperand(OperandVector &Operands, SMLoc NameLoc,
WebAssembly::BlockType BT) {
Operands.push_back(std::make_unique<WebAssemblyOperand>(
WebAssemblyOperand::Integer, NameLoc, NameLoc,
WebAssemblyOperand::IntOp{static_cast<int64_t>(BT)}));
}
bool ParseInstruction(ParseInstructionInfo & /*Info*/, StringRef Name,
SMLoc NameLoc, OperandVector &Operands) override {
// Note: Name does NOT point into the sourcecode, but to a local, so
// use NameLoc instead.
Name = StringRef(NameLoc.getPointer(), Name.size());
// WebAssembly has instructions with / in them, which AsmLexer parses
// as separate tokens, so if we find such tokens immediately adjacent (no
// whitespace), expand the name to include them:
for (;;) {
auto &Sep = Lexer.getTok();
if (Sep.getLoc().getPointer() != Name.end() ||
Sep.getKind() != AsmToken::Slash)
break;
// Extend name with /
Name = StringRef(Name.begin(), Name.size() + Sep.getString().size());
Parser.Lex();
// We must now find another identifier, or error.
auto &Id = Lexer.getTok();
if (Id.getKind() != AsmToken::Identifier ||
Id.getLoc().getPointer() != Name.end())
return error("Incomplete instruction name: ", Id);
Name = StringRef(Name.begin(), Name.size() + Id.getString().size());
Parser.Lex();
}
// Now construct the name as first operand.
Operands.push_back(std::make_unique<WebAssemblyOperand>(
WebAssemblyOperand::Token, NameLoc, SMLoc::getFromPointer(Name.end()),
WebAssemblyOperand::TokOp{Name}));
// If this instruction is part of a control flow structure, ensure
// proper nesting.
bool ExpectBlockType = false;
bool ExpectFuncType = false;
bool ExpectHeapType = false;
if (Name == "block") {
push(Block);
ExpectBlockType = true;
} else if (Name == "loop") {
push(Loop);
ExpectBlockType = true;
} else if (Name == "try") {
push(Try);
ExpectBlockType = true;
} else if (Name == "if") {
push(If);
ExpectBlockType = true;
} else if (Name == "else") {
if (pop(Name, If))
return true;
push(Else);
} else if (Name == "catch") {
if (pop(Name, Try))
return true;
push(Try);
} else if (Name == "end_if") {
if (pop(Name, If, Else))
return true;
} else if (Name == "end_try") {
if (pop(Name, Try))
return true;
} else if (Name == "end_loop") {
if (pop(Name, Loop))
return true;
} else if (Name == "end_block") {
if (pop(Name, Block))
return true;
} else if (Name == "end_function") {
ensureLocals(getStreamer());
CurrentState = EndFunction;
if (pop(Name, Function) || ensureEmptyNestingStack())
return true;
} else if (Name == "call_indirect" || Name == "return_call_indirect") {
ExpectFuncType = true;
// Ensure that the object file has a __indirect_function_table import, as
// we call_indirect against it.
auto &Ctx = getStreamer().getContext();
MCSymbolWasm *Sym =
GetOrCreateFunctionTableSymbol(Ctx, "__indirect_function_table");
// Until call_indirect emits TABLE_NUMBER relocs against this symbol, mark
// it as NO_STRIP so as to ensure that the indirect function table makes
// it to linked output.
Sym->setNoStrip();
} else if (Name == "ref.null") {
ExpectHeapType = true;
}
if (ExpectFuncType || (ExpectBlockType && Lexer.is(AsmToken::LParen))) {
// This has a special TYPEINDEX operand which in text we
// represent as a signature, such that we can re-build this signature,
// attach it to an anonymous symbol, which is what WasmObjectWriter
// expects to be able to recreate the actual unique-ified type indices.
auto Loc = Parser.getTok();
auto Signature = std::make_unique<wasm::WasmSignature>();
if (parseSignature(Signature.get()))
return true;
// Got signature as block type, don't need more
ExpectBlockType = false;
auto &Ctx = getStreamer().getContext();
// The "true" here will cause this to be a nameless symbol.
MCSymbol *Sym = Ctx.createTempSymbol("typeindex", true);
auto *WasmSym = cast<MCSymbolWasm>(Sym);
WasmSym->setSignature(Signature.get());
addSignature(std::move(Signature));
WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
const MCExpr *Expr = MCSymbolRefExpr::create(
WasmSym, MCSymbolRefExpr::VK_WASM_TYPEINDEX, Ctx);
Operands.push_back(std::make_unique<WebAssemblyOperand>(
WebAssemblyOperand::Symbol, Loc.getLoc(), Loc.getEndLoc(),
WebAssemblyOperand::SymOp{Expr}));
}
while (Lexer.isNot(AsmToken::EndOfStatement)) {
auto &Tok = Lexer.getTok();
switch (Tok.getKind()) {
case AsmToken::Identifier: {
if (!parseSpecialFloatMaybe(false, Operands))
break;
auto &Id = Lexer.getTok();
if (ExpectBlockType) {
// Assume this identifier is a block_type.
auto BT = parseBlockType(Id.getString());
if (BT == WebAssembly::BlockType::Invalid)
return error("Unknown block type: ", Id);
addBlockTypeOperand(Operands, NameLoc, BT);
Parser.Lex();
} else if (ExpectHeapType) {
auto HeapType = parseHeapType(Id.getString());
if (HeapType == WebAssembly::HeapType::Invalid) {
return error("Expected a heap type: ", Id);
}
Operands.push_back(std::make_unique<WebAssemblyOperand>(
WebAssemblyOperand::Integer, Id.getLoc(), Id.getEndLoc(),
WebAssemblyOperand::IntOp{static_cast<int64_t>(HeapType)}));
Parser.Lex();
} else {
// Assume this identifier is a label.
const MCExpr *Val;
SMLoc End;
if (Parser.parseExpression(Val, End))
return error("Cannot parse symbol: ", Lexer.getTok());
Operands.push_back(std::make_unique<WebAssemblyOperand>(
WebAssemblyOperand::Symbol, Id.getLoc(), Id.getEndLoc(),
WebAssemblyOperand::SymOp{Val}));
if (checkForP2AlignIfLoadStore(Operands, Name))
return true;
}
break;
}
case AsmToken::Minus:
Parser.Lex();
if (Lexer.is(AsmToken::Integer)) {
parseSingleInteger(true, Operands);
if (checkForP2AlignIfLoadStore(Operands, Name))
return true;
} else if(Lexer.is(AsmToken::Real)) {
if (parseSingleFloat(true, Operands))
return true;
} else if (!parseSpecialFloatMaybe(true, Operands)) {
} else {
return error("Expected numeric constant instead got: ",
Lexer.getTok());
}
break;
case AsmToken::Integer:
parseSingleInteger(false, Operands);
if (checkForP2AlignIfLoadStore(Operands, Name))
return true;
break;
case AsmToken::Real: {
if (parseSingleFloat(false, Operands))
return true;
break;
}
case AsmToken::LCurly: {
Parser.Lex();
auto Op = std::make_unique<WebAssemblyOperand>(
WebAssemblyOperand::BrList, Tok.getLoc(), Tok.getEndLoc());
if (!Lexer.is(AsmToken::RCurly))
for (;;) {
Op->BrL.List.push_back(Lexer.getTok().getIntVal());
expect(AsmToken::Integer, "integer");
if (!isNext(AsmToken::Comma))
break;
}
expect(AsmToken::RCurly, "}");
Operands.push_back(std::move(Op));
break;
}
default:
return error("Unexpected token in operand: ", Tok);
}
if (Lexer.isNot(AsmToken::EndOfStatement)) {
if (expect(AsmToken::Comma, ","))
return true;
}
}
if (ExpectBlockType && Operands.size() == 1) {
// Support blocks with no operands as default to void.
addBlockTypeOperand(Operands, NameLoc, WebAssembly::BlockType::Void);
}
Parser.Lex();
return false;
}
void onLabelParsed(MCSymbol *Symbol) override {
LastLabel = Symbol;
CurrentState = Label;
}
bool parseSignature(wasm::WasmSignature *Signature) {
if (expect(AsmToken::LParen, "("))
return true;
if (parseRegTypeList(Signature->Params))
return true;
if (expect(AsmToken::RParen, ")"))
return true;
if (expect(AsmToken::MinusGreater, "->"))
return true;
if (expect(AsmToken::LParen, "("))
return true;
if (parseRegTypeList(Signature->Returns))
return true;
if (expect(AsmToken::RParen, ")"))
return true;
return false;
}
bool CheckDataSection() {
if (CurrentState != DataSection) {
auto WS = cast<MCSectionWasm>(getStreamer().getCurrentSection().first);
if (WS && WS->getKind().isText())
return error("data directive must occur in a data segment: ",
Lexer.getTok());
}
CurrentState = DataSection;
return false;
}
// This function processes wasm-specific directives streamed to
// WebAssemblyTargetStreamer, all others go to the generic parser
// (see WasmAsmParser).
bool ParseDirective(AsmToken DirectiveID) override {
// This function has a really weird return value behavior that is different
// from all the other parsing functions:
// - return true && no tokens consumed -> don't know this directive / let
// the generic parser handle it.
// - return true && tokens consumed -> a parsing error occurred.
// - return false -> processed this directive successfully.
assert(DirectiveID.getKind() == AsmToken::Identifier);
auto &Out = getStreamer();
auto &TOut =
reinterpret_cast<WebAssemblyTargetStreamer &>(*Out.getTargetStreamer());
auto &Ctx = Out.getContext();
// TODO: any time we return an error, at least one token must have been
// consumed, otherwise this will not signal an error to the caller.
if (DirectiveID.getString() == ".globaltype") {
auto SymName = expectIdent();
if (SymName.empty())
return true;
if (expect(AsmToken::Comma, ","))
return true;
auto TypeTok = Lexer.getTok();
auto TypeName = expectIdent();
if (TypeName.empty())
return true;
auto Type = parseType(TypeName);
if (!Type)
return error("Unknown type in .globaltype directive: ", TypeTok);
// Optional mutable modifier. Default to mutable for historical reasons.
// Ideally we would have gone with immutable as the default and used `mut`
// as the modifier to match the `.wat` format.
bool Mutable = true;
if (isNext(AsmToken::Comma)) {
TypeTok = Lexer.getTok();
auto Id = expectIdent();
if (Id == "immutable")
Mutable = false;
else
// Should we also allow `mutable` and `mut` here for clarity?
return error("Unknown type in .globaltype modifier: ", TypeTok);
}
// Now set this symbol with the correct type.
auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
WasmSym->setType(wasm::WASM_SYMBOL_TYPE_GLOBAL);
WasmSym->setGlobalType(
wasm::WasmGlobalType{uint8_t(Type.getValue()), Mutable});
// And emit the directive again.
TOut.emitGlobalType(WasmSym);
return expect(AsmToken::EndOfStatement, "EOL");
}
if (DirectiveID.getString() == ".tabletype") {
auto SymName = expectIdent();
if (SymName.empty())
return true;
if (expect(AsmToken::Comma, ","))
return true;
auto TypeTok = Lexer.getTok();
auto TypeName = expectIdent();
if (TypeName.empty())
return true;
auto Type = parseType(TypeName);
if (!Type)
return error("Unknown type in .tabletype directive: ", TypeTok);
// Now that we have the name and table type, we can actually create the
// symbol
auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
WasmSym->setType(wasm::WASM_SYMBOL_TYPE_TABLE);
WasmSym->setTableType(Type.getValue());
TOut.emitTableType(WasmSym);
return expect(AsmToken::EndOfStatement, "EOL");
}
if (DirectiveID.getString() == ".functype") {
// This code has to send things to the streamer similar to
// WebAssemblyAsmPrinter::EmitFunctionBodyStart.
// TODO: would be good to factor this into a common function, but the
// assembler and backend really don't share any common code, and this code
// parses the locals separately.
auto SymName = expectIdent();
if (SymName.empty())
return true;
auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
if (CurrentState == Label && WasmSym == LastLabel) {
// This .functype indicates a start of a function.
if (ensureEmptyNestingStack())
return true;
CurrentState = FunctionStart;
LastFunctionLabel = LastLabel;
push(Function);
}
auto Signature = std::make_unique<wasm::WasmSignature>();
if (parseSignature(Signature.get()))
return true;
WasmSym->setSignature(Signature.get());
addSignature(std::move(Signature));
WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
TOut.emitFunctionType(WasmSym);
// TODO: backend also calls TOut.emitIndIdx, but that is not implemented.
return expect(AsmToken::EndOfStatement, "EOL");
}
if (DirectiveID.getString() == ".export_name") {
auto SymName = expectIdent();
if (SymName.empty())
return true;
if (expect(AsmToken::Comma, ","))
return true;
auto ExportName = expectIdent();
auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
WasmSym->setExportName(storeName(ExportName));
TOut.emitExportName(WasmSym, ExportName);
}
if (DirectiveID.getString() == ".import_module") {
auto SymName = expectIdent();
if (SymName.empty())
return true;
if (expect(AsmToken::Comma, ","))
return true;
auto ImportModule = expectIdent();
auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
WasmSym->setImportModule(storeName(ImportModule));
TOut.emitImportModule(WasmSym, ImportModule);
}
if (DirectiveID.getString() == ".import_name") {
auto SymName = expectIdent();
if (SymName.empty())
return true;
if (expect(AsmToken::Comma, ","))
return true;
auto ImportName = expectIdent();
auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
WasmSym->setImportName(storeName(ImportName));
TOut.emitImportName(WasmSym, ImportName);
}
if (DirectiveID.getString() == ".eventtype") {
auto SymName = expectIdent();
if (SymName.empty())
return true;
auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
auto Signature = std::make_unique<wasm::WasmSignature>();
if (parseRegTypeList(Signature->Params))
return true;
WasmSym->setSignature(Signature.get());
addSignature(std::move(Signature));
WasmSym->setType(wasm::WASM_SYMBOL_TYPE_EVENT);
TOut.emitEventType(WasmSym);
// TODO: backend also calls TOut.emitIndIdx, but that is not implemented.
return expect(AsmToken::EndOfStatement, "EOL");
}
if (DirectiveID.getString() == ".local") {
if (CurrentState != FunctionStart)
return error(".local directive should follow the start of a function",
Lexer.getTok());
SmallVector<wasm::ValType, 4> Locals;
if (parseRegTypeList(Locals))
return true;
TOut.emitLocal(Locals);
CurrentState = FunctionLocals;
return expect(AsmToken::EndOfStatement, "EOL");
}
if (DirectiveID.getString() == ".int8" ||
DirectiveID.getString() == ".int16" ||
DirectiveID.getString() == ".int32" ||
DirectiveID.getString() == ".int64") {
if (CheckDataSection()) return true;
const MCExpr *Val;
SMLoc End;
if (Parser.parseExpression(Val, End))
return error("Cannot parse .int expression: ", Lexer.getTok());
size_t NumBits = 0;
DirectiveID.getString().drop_front(4).getAsInteger(10, NumBits);
Out.emitValue(Val, NumBits / 8, End);
return expect(AsmToken::EndOfStatement, "EOL");
}
if (DirectiveID.getString() == ".asciz") {
if (CheckDataSection()) return true;
std::string S;
if (Parser.parseEscapedString(S))
return error("Cannot parse string constant: ", Lexer.getTok());
Out.emitBytes(StringRef(S.c_str(), S.length() + 1));
return expect(AsmToken::EndOfStatement, "EOL");
}
return true; // We didn't process this directive.
}
// Called either when the first instruction is parsed of the function ends.
void ensureLocals(MCStreamer &Out) {
if (CurrentState == FunctionStart) {
// We haven't seen a .local directive yet. The streamer requires locals to
// be encoded as a prelude to the instructions, so emit an empty list of
// locals here.
auto &TOut = reinterpret_cast<WebAssemblyTargetStreamer &>(
*Out.getTargetStreamer());
TOut.emitLocal(SmallVector<wasm::ValType, 0>());
CurrentState = FunctionLocals;
}
}
bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned & /*Opcode*/,
OperandVector &Operands, MCStreamer &Out,
uint64_t &ErrorInfo,
bool MatchingInlineAsm) override {
MCInst Inst;
Inst.setLoc(IDLoc);
FeatureBitset MissingFeatures;
unsigned MatchResult = MatchInstructionImpl(
Operands, Inst, ErrorInfo, MissingFeatures, MatchingInlineAsm);
switch (MatchResult) {
case Match_Success: {
ensureLocals(Out);
// Fix unknown p2align operands.
auto Align = WebAssembly::GetDefaultP2AlignAny(Inst.getOpcode());
if (Align != -1U) {
auto &Op0 = Inst.getOperand(0);
if (Op0.getImm() == -1)
Op0.setImm(Align);
}
if (getSTI().getTargetTriple().isArch64Bit()) {
// Upgrade 32-bit loads/stores to 64-bit. These mostly differ by having
// an offset64 arg instead of offset32, but to the assembler matcher
// they're both immediates so don't get selected for.
auto Opc64 = WebAssembly::getWasm64Opcode(
static_cast<uint16_t>(Inst.getOpcode()));
if (Opc64 >= 0) {
Inst.setOpcode(Opc64);
}
}
Out.emitInstruction(Inst, getSTI());
if (CurrentState == EndFunction) {
onEndOfFunction();
} else {
CurrentState = Instructions;
}
return false;
}
case Match_MissingFeature: {
assert(MissingFeatures.count() > 0 && "Expected missing features");
SmallString<128> Message;
raw_svector_ostream OS(Message);
OS << "instruction requires:";
for (unsigned i = 0, e = MissingFeatures.size(); i != e; ++i)
if (MissingFeatures.test(i))
OS << ' ' << getSubtargetFeatureName(i);
return Parser.Error(IDLoc, Message);
}
case Match_MnemonicFail:
return Parser.Error(IDLoc, "invalid instruction");
case Match_NearMisses:
return Parser.Error(IDLoc, "ambiguous instruction");
case Match_InvalidTiedOperand:
case Match_InvalidOperand: {
SMLoc ErrorLoc = IDLoc;
if (ErrorInfo != ~0ULL) {
if (ErrorInfo >= Operands.size())
return Parser.Error(IDLoc, "too few operands for instruction");
ErrorLoc = Operands[ErrorInfo]->getStartLoc();
if (ErrorLoc == SMLoc())
ErrorLoc = IDLoc;
}
return Parser.Error(ErrorLoc, "invalid operand for instruction");
}
}
llvm_unreachable("Implement any new match types added!");
}
void doBeforeLabelEmit(MCSymbol *Symbol) override {
// Start a new section for the next function automatically, since our
// object writer expects each function to have its own section. This way
// The user can't forget this "convention".
auto SymName = Symbol->getName();
if (SymName.startswith(".L"))
return; // Local Symbol.
// Only create a new text section if we're already in one.
// TODO: If the user explicitly creates a new function section, we ignore
// its name when we create this one. It would be nice to honor their
// choice, while still ensuring that we create one if they forget.
// (that requires coordination with WasmAsmParser::parseSectionDirective)
auto CWS = cast<MCSectionWasm>(getStreamer().getCurrentSection().first);
if (!CWS || !CWS->getKind().isText())
return;
auto SecName = ".text." + SymName;
auto *Group = CWS->getGroup();
// If the current section is a COMDAT, also set the flag on the symbol.
// TODO: Currently the only place that the symbols' comdat flag matters is
// for importing comdat functions. But there's no way to specify that in
// assembly currently.
if (Group)
cast<MCSymbolWasm>(Symbol)->setComdat(true);
auto *WS =
getContext().getWasmSection(SecName, SectionKind::getText(), Group,
MCContext::GenericSectionID, nullptr);
getStreamer().SwitchSection(WS);
// Also generate DWARF for this section if requested.
if (getContext().getGenDwarfForAssembly())
getContext().addGenDwarfSection(WS);
}
void onEndOfFunction() {
// Automatically output a .size directive, so it becomes optional for the
// user.
if (!LastFunctionLabel) return;
auto TempSym = getContext().createLinkerPrivateTempSymbol();
getStreamer().emitLabel(TempSym);
auto Start = MCSymbolRefExpr::create(LastFunctionLabel, getContext());
auto End = MCSymbolRefExpr::create(TempSym, getContext());
auto Expr =
MCBinaryExpr::create(MCBinaryExpr::Sub, End, Start, getContext());
getStreamer().emitELFSize(LastFunctionLabel, Expr);
}
void onEndOfFile() override { ensureEmptyNestingStack(); }
};
} // end anonymous namespace
// Force static initialization.
extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeWebAssemblyAsmParser() {
RegisterMCAsmParser<WebAssemblyAsmParser> X(getTheWebAssemblyTarget32());
RegisterMCAsmParser<WebAssemblyAsmParser> Y(getTheWebAssemblyTarget64());
}
#define GET_REGISTER_MATCHER
#define GET_SUBTARGET_FEATURE_NAME
#define GET_MATCHER_IMPLEMENTATION
#include "WebAssemblyGenAsmMatcher.inc"
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