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//===-- LanaiAsmPrinter.cpp - Lanai LLVM assembly writer ------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file contains a printer that converts from our internal representation
// of machine-dependent LLVM code to the Lanai assembly language.
//
//===----------------------------------------------------------------------===//
#include "MCTargetDesc/LanaiInstPrinter.h"
#include "LanaiAluCode.h"
#include "LanaiCondCode.h"
#include "LanaiInstrInfo.h"
#include "LanaiMCInstLower.h"
#include "LanaiTargetMachine.h"
#include "TargetInfo/LanaiTargetInfo.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstBuilder.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
#define DEBUG_TYPE "asm-printer"
using namespace llvm;
namespace {
class LanaiAsmPrinter : public AsmPrinter {
public:
explicit LanaiAsmPrinter(TargetMachine &TM,
std::unique_ptr<MCStreamer> Streamer)
: AsmPrinter(TM, std::move(Streamer)) {}
StringRef getPassName() const override { return "Lanai Assembly Printer"; }
void printOperand(const MachineInstr *MI, int OpNum, raw_ostream &O);
bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
const char *ExtraCode, raw_ostream &O) override;
void EmitInstruction(const MachineInstr *MI) override;
bool isBlockOnlyReachableByFallthrough(
const MachineBasicBlock *MBB) const override;
private:
void customEmitInstruction(const MachineInstr *MI);
void emitCallInstruction(const MachineInstr *MI);
};
} // end of anonymous namespace
void LanaiAsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(OpNum);
switch (MO.getType()) {
case MachineOperand::MO_Register:
O << LanaiInstPrinter::getRegisterName(MO.getReg());
break;
case MachineOperand::MO_Immediate:
O << MO.getImm();
break;
case MachineOperand::MO_MachineBasicBlock:
O << *MO.getMBB()->getSymbol();
break;
case MachineOperand::MO_GlobalAddress:
O << *getSymbol(MO.getGlobal());
break;
case MachineOperand::MO_BlockAddress: {
MCSymbol *BA = GetBlockAddressSymbol(MO.getBlockAddress());
O << BA->getName();
break;
}
case MachineOperand::MO_ExternalSymbol:
O << *GetExternalSymbolSymbol(MO.getSymbolName());
break;
case MachineOperand::MO_JumpTableIndex:
O << MAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber() << '_'
<< MO.getIndex();
break;
case MachineOperand::MO_ConstantPoolIndex:
O << MAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber() << '_'
<< MO.getIndex();
return;
default:
llvm_unreachable("<unknown operand type>");
}
}
// PrintAsmOperand - Print out an operand for an inline asm expression.
bool LanaiAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
const char *ExtraCode, raw_ostream &O) {
// Does this asm operand have a single letter operand modifier?
if (ExtraCode && ExtraCode[0]) {
if (ExtraCode[1])
return true; // Unknown modifier.
switch (ExtraCode[0]) {
// The highest-numbered register of a pair.
case 'H': {
if (OpNo == 0)
return true;
const MachineOperand &FlagsOP = MI->getOperand(OpNo - 1);
if (!FlagsOP.isImm())
return true;
unsigned Flags = FlagsOP.getImm();
unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags);
if (NumVals != 2)
return true;
unsigned RegOp = OpNo + 1;
if (RegOp >= MI->getNumOperands())
return true;
const MachineOperand &MO = MI->getOperand(RegOp);
if (!MO.isReg())
return true;
Register Reg = MO.getReg();
O << LanaiInstPrinter::getRegisterName(Reg);
return false;
}
default:
return AsmPrinter::PrintAsmOperand(MI, OpNo, ExtraCode, O);
}
}
printOperand(MI, OpNo, O);
return false;
}
//===----------------------------------------------------------------------===//
void LanaiAsmPrinter::emitCallInstruction(const MachineInstr *MI) {
assert((MI->getOpcode() == Lanai::CALL || MI->getOpcode() == Lanai::CALLR) &&
"Unsupported call function");
LanaiMCInstLower MCInstLowering(OutContext, *this);
MCSubtargetInfo STI = getSubtargetInfo();
// Insert save rca instruction immediately before the call.
// TODO: We should generate a pc-relative mov instruction here instead
// of pc + 16 (should be mov .+16 %rca).
OutStreamer->EmitInstruction(MCInstBuilder(Lanai::ADD_I_LO)
.addReg(Lanai::RCA)
.addReg(Lanai::PC)
.addImm(16),
STI);
// Push rca onto the stack.
// st %rca, [--%sp]
OutStreamer->EmitInstruction(MCInstBuilder(Lanai::SW_RI)
.addReg(Lanai::RCA)
.addReg(Lanai::SP)
.addImm(-4)
.addImm(LPAC::makePreOp(LPAC::ADD)),
STI);
// Lower the call instruction.
if (MI->getOpcode() == Lanai::CALL) {
MCInst TmpInst;
MCInstLowering.Lower(MI, TmpInst);
TmpInst.setOpcode(Lanai::BT);
OutStreamer->EmitInstruction(TmpInst, STI);
} else {
OutStreamer->EmitInstruction(MCInstBuilder(Lanai::ADD_R)
.addReg(Lanai::PC)
.addReg(MI->getOperand(0).getReg())
.addReg(Lanai::R0)
.addImm(LPCC::ICC_T),
STI);
}
}
void LanaiAsmPrinter::customEmitInstruction(const MachineInstr *MI) {
LanaiMCInstLower MCInstLowering(OutContext, *this);
MCSubtargetInfo STI = getSubtargetInfo();
MCInst TmpInst;
MCInstLowering.Lower(MI, TmpInst);
OutStreamer->EmitInstruction(TmpInst, STI);
}
void LanaiAsmPrinter::EmitInstruction(const MachineInstr *MI) {
MachineBasicBlock::const_instr_iterator I = MI->getIterator();
MachineBasicBlock::const_instr_iterator E = MI->getParent()->instr_end();
do {
if (I->isCall()) {
emitCallInstruction(&*I);
continue;
}
customEmitInstruction(&*I);
} while ((++I != E) && I->isInsideBundle());
}
// isBlockOnlyReachableByFallthough - Return true if the basic block has
// exactly one predecessor and the control transfer mechanism between
// the predecessor and this block is a fall-through.
// FIXME: could the overridden cases be handled in AnalyzeBranch?
bool LanaiAsmPrinter::isBlockOnlyReachableByFallthrough(
const MachineBasicBlock *MBB) const {
// The predecessor has to be immediately before this block.
const MachineBasicBlock *Pred = *MBB->pred_begin();
// If the predecessor is a switch statement, assume a jump table
// implementation, so it is not a fall through.
if (const BasicBlock *B = Pred->getBasicBlock())
if (isa<SwitchInst>(B->getTerminator()))
return false;
// Check default implementation
if (!AsmPrinter::isBlockOnlyReachableByFallthrough(MBB))
return false;
// Otherwise, check the last instruction.
// Check if the last terminator is an unconditional branch.
MachineBasicBlock::const_iterator I = Pred->end();
while (I != Pred->begin() && !(--I)->isTerminator()) {
}
return !I->isBarrier();
}
// Force static initialization.
extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeLanaiAsmPrinter() {
RegisterAsmPrinter<LanaiAsmPrinter> X(getTheLanaiTarget());
}