//=- WebAssemblyInstPrinter.cpp - WebAssembly assembly instruction printing -=//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief Print MCInst instructions to wasm format.
///
//===----------------------------------------------------------------------===//
#include "InstPrinter/WebAssemblyInstPrinter.h"
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "WebAssembly.h"
#include "WebAssemblyMachineFunctionInfo.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Target/TargetRegisterInfo.h"
using namespace llvm;
#define DEBUG_TYPE "asm-printer"
#include "WebAssemblyGenAsmWriter.inc"
WebAssemblyInstPrinter::WebAssemblyInstPrinter(const MCAsmInfo &MAI,
const MCInstrInfo &MII,
const MCRegisterInfo &MRI)
: MCInstPrinter(MAI, MII, MRI), ControlFlowCounter(0) {}
void WebAssemblyInstPrinter::printRegName(raw_ostream &OS,
unsigned RegNo) const {
assert(RegNo != WebAssemblyFunctionInfo::UnusedReg);
// Note that there's an implicit get_local/set_local here!
OS << "$" << RegNo;
}
void WebAssemblyInstPrinter::printInst(const MCInst *MI, raw_ostream &OS,
StringRef Annot,
const MCSubtargetInfo & /*STI*/) {
// Print the instruction (this uses the AsmStrings from the .td files).
printInstruction(MI, OS);
// Print any additional variadic operands.
const MCInstrDesc &Desc = MII.get(MI->getOpcode());
if (Desc.isVariadic())
for (auto i = Desc.getNumOperands(), e = MI->getNumOperands(); i < e; ++i) {
if (i != 0)
OS << ", ";
printOperand(MI, i, OS);
}
// Print any added annotation.
printAnnotation(OS, Annot);
if (CommentStream) {
// Observe any effects on the control flow stack, for use in annotating
// control flow label references.
switch (MI->getOpcode()) {
default:
break;
case WebAssembly::LOOP: {
// Grab the TopLabel value first so that labels print in numeric order.
uint64_t TopLabel = ControlFlowCounter++;
ControlFlowStack.push_back(std::make_pair(ControlFlowCounter++, false));
printAnnotation(OS, "label" + utostr(TopLabel) + ':');
ControlFlowStack.push_back(std::make_pair(TopLabel, true));
break;
}
case WebAssembly::BLOCK:
ControlFlowStack.push_back(std::make_pair(ControlFlowCounter++, false));
break;
case WebAssembly::END_LOOP:
ControlFlowStack.pop_back();
printAnnotation(
OS, "label" + utostr(ControlFlowStack.pop_back_val().first) + ':');
break;
case WebAssembly::END_BLOCK:
printAnnotation(
OS, "label" + utostr(ControlFlowStack.pop_back_val().first) + ':');
break;
}
// Annotate any control flow label references.
unsigned NumFixedOperands = Desc.NumOperands;
SmallSet<uint64_t, 8> Printed;
for (unsigned i = 0, e = MI->getNumOperands(); i < e; ++i) {
const MCOperandInfo &Info = Desc.OpInfo[i];
if (!(i < NumFixedOperands
? (Info.OperandType == WebAssembly::OPERAND_BASIC_BLOCK)
: (Desc.TSFlags & WebAssemblyII::VariableOpImmediateIsLabel)))
continue;
uint64_t Depth = MI->getOperand(i).getImm();
if (!Printed.insert(Depth).second)
continue;
const auto &Pair = ControlFlowStack.rbegin()[Depth];
printAnnotation(OS, utostr(Depth) + ": " + (Pair.second ? "up" : "down") +
" to label" + utostr(Pair.first));
}
}
}
static std::string toString(const APFloat &FP) {
// Print NaNs with custom payloads specially.
if (FP.isNaN() &&
!FP.bitwiseIsEqual(APFloat::getQNaN(FP.getSemantics())) &&
!FP.bitwiseIsEqual(APFloat::getQNaN(FP.getSemantics(), /*Negative=*/true))) {
APInt AI = FP.bitcastToAPInt();
return
std::string(AI.isNegative() ? "-" : "") + "nan:0x" +
utohexstr(AI.getZExtValue() &
(AI.getBitWidth() == 32 ? INT64_C(0x007fffff) :
INT64_C(0x000fffffffffffff)),
/*LowerCase=*/true);
}
// Use C99's hexadecimal floating-point representation.
static const size_t BufBytes = 128;
char buf[BufBytes];
auto Written = FP.convertToHexString(
buf, /*hexDigits=*/0, /*upperCase=*/false, APFloat::rmNearestTiesToEven);
(void)Written;
assert(Written != 0);
assert(Written < BufBytes);
return buf;
}
void WebAssemblyInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
raw_ostream &O) {
const MCOperand &Op = MI->getOperand(OpNo);
if (Op.isReg()) {
assert((OpNo < MII.get(MI->getOpcode()).getNumOperands() ||
MII.get(MI->getOpcode()).TSFlags == 0) &&
"WebAssembly variable_ops register ops don't use TSFlags");
unsigned WAReg = Op.getReg();
if (int(WAReg) >= 0)
printRegName(O, WAReg);
else if (OpNo >= MII.get(MI->getOpcode()).getNumDefs())
O << "$pop" << WebAssemblyFunctionInfo::getWARegStackId(WAReg);
else if (WAReg != WebAssemblyFunctionInfo::UnusedReg)
O << "$push" << WebAssemblyFunctionInfo::getWARegStackId(WAReg);
else
O << "$drop";
// Add a '=' suffix if this is a def.
if (OpNo < MII.get(MI->getOpcode()).getNumDefs())
O << '=';
} else if (Op.isImm()) {
assert((OpNo < MII.get(MI->getOpcode()).getNumOperands() ||
(MII.get(MI->getOpcode()).TSFlags &
WebAssemblyII::VariableOpIsImmediate)) &&
"WebAssemblyII::VariableOpIsImmediate should be set for "
"variable_ops immediate ops");
// TODO: (MII.get(MI->getOpcode()).TSFlags &
// WebAssemblyII::VariableOpImmediateIsLabel)
// can tell us whether this is an immediate referencing a label in the
// control flow stack, and it may be nice to pretty-print.
O << Op.getImm();
} else if (Op.isFPImm()) {
const MCInstrDesc &Desc = MII.get(MI->getOpcode());
assert(OpNo < Desc.getNumOperands() &&
"Unexpected floating-point immediate as a non-fixed operand");
assert(Desc.TSFlags == 0 &&
"WebAssembly variable_ops floating point ops don't use TSFlags");
const MCOperandInfo &Info = Desc.OpInfo[OpNo];
if (Info.OperandType == WebAssembly::OPERAND_FP32IMM) {
// TODO: MC converts all floating point immediate operands to double.
// This is fine for numeric values, but may cause NaNs to change bits.
O << toString(APFloat(float(Op.getFPImm())));
} else {
assert(Info.OperandType == WebAssembly::OPERAND_FP64IMM);
O << toString(APFloat(Op.getFPImm()));
}
} else {
assert((OpNo < MII.get(MI->getOpcode()).getNumOperands() ||
(MII.get(MI->getOpcode()).TSFlags &
WebAssemblyII::VariableOpIsImmediate)) &&
"WebAssemblyII::VariableOpIsImmediate should be set for "
"variable_ops expr ops");
assert(Op.isExpr() && "unknown operand kind in printOperand");
Op.getExpr()->print(O, &MAI);
}
}
void
WebAssemblyInstPrinter::printWebAssemblyP2AlignOperand(const MCInst *MI,
unsigned OpNo,
raw_ostream &O) {
int64_t Imm = MI->getOperand(OpNo).getImm();
if (Imm == WebAssembly::GetDefaultP2Align(MI->getOpcode()))
return;
O << ":p2align=" << Imm;
}
const char *llvm::WebAssembly::TypeToString(MVT Ty) {
switch (Ty.SimpleTy) {
case MVT::i32:
return "i32";
case MVT::i64:
return "i64";
case MVT::f32:
return "f32";
case MVT::f64:
return "f64";
default:
llvm_unreachable("unsupported type");
}
}