lib/Target/MSP430/MSP430AsmPrinter.cpp

   1 //===-- MSP430AsmPrinter.cpp - MSP430 LLVM assembly writer ----------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file contains a printer that converts from our internal representation
  10 // of machine-dependent LLVM code to the MSP430 assembly language.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "MCTargetDesc/MSP430InstPrinter.h"
  15 #include "MSP430.h"
  16 #include "MSP430InstrInfo.h"
  17 #include "MSP430MCInstLower.h"
  18 #include "MSP430TargetMachine.h"
  19 #include "TargetInfo/MSP430TargetInfo.h"
  20 #include "llvm/BinaryFormat/ELF.h"
  21 #include "llvm/CodeGen/AsmPrinter.h"
  22 #include "llvm/CodeGen/MachineConstantPool.h"
  23 #include "llvm/CodeGen/MachineFunctionPass.h"
  24 #include "llvm/CodeGen/MachineInstr.h"
  25 #include "llvm/CodeGen/MachineModuleInfo.h"
  26 #include "llvm/IR/Constants.h"
  27 #include "llvm/IR/DerivedTypes.h"
  28 #include "llvm/IR/Mangler.h"
  29 #include "llvm/IR/Module.h"
  30 #include "llvm/MC/MCAsmInfo.h"
  31 #include "llvm/MC/MCInst.h"
  32 #include "llvm/MC/MCSectionELF.h"
  33 #include "llvm/MC/MCStreamer.h"
  34 #include "llvm/MC/MCSymbol.h"
  35 #include "llvm/Support/TargetRegistry.h"
  36 #include "llvm/Support/raw_ostream.h"
  37 using namespace llvm;
  38
  39 #define DEBUG_TYPE "asm-printer"
  40
  41 namespace {
  42   class MSP430AsmPrinter : public AsmPrinter {
  43   public:
  44     MSP430AsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
  45         : AsmPrinter(TM, std::move(Streamer)) {}
  46
  47     StringRef getPassName() const override { return "MSP430 Assembly Printer"; }
  48
  49     bool runOnMachineFunction(MachineFunction &MF) override;
  50
  51     void PrintSymbolOperand(const MachineOperand &MO, raw_ostream &O) override;
  52     void printOperand(const MachineInstr *MI, int OpNum,
  53                       raw_ostream &O, const char* Modifier = nullptr);
  54     void printSrcMemOperand(const MachineInstr *MI, int OpNum,
  55                             raw_ostream &O);
  56     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
  57                          const char *ExtraCode, raw_ostream &O) override;
  58     bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
  59                                const char *ExtraCode, raw_ostream &O) override;
  60     void EmitInstruction(const MachineInstr *MI) override;
  61
  62     void EmitInterruptVectorSection(MachineFunction &ISR);
  63   };
  64 } // end of anonymous namespace
  65
  66 void MSP430AsmPrinter::PrintSymbolOperand(const MachineOperand &MO,
  67                                           raw_ostream &O) {
  68   uint64_t Offset = MO.getOffset();
  69   if (Offset)
  70     O << '(' << Offset << '+';
  71
  72   getSymbol(MO.getGlobal())->print(O, MAI);
  73
  74   if (Offset)
  75     O << ')';
  76 }
  77
  78 void MSP430AsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
  79                                     raw_ostream &O, const char *Modifier) {
  80   const MachineOperand &MO = MI->getOperand(OpNum);
  81   switch (MO.getType()) {
  82   default: llvm_unreachable("Not implemented yet!");
  83   case MachineOperand::MO_Register:
  84     O << MSP430InstPrinter::getRegisterName(MO.getReg());
  85     return;
  86   case MachineOperand::MO_Immediate:
  87     if (!Modifier || strcmp(Modifier, "nohash"))
  88       O << '#';
  89     O << MO.getImm();
  90     return;
  91   case MachineOperand::MO_MachineBasicBlock:
  92     MO.getMBB()->getSymbol()->print(O, MAI);
  93     return;
  94   case MachineOperand::MO_GlobalAddress: {
  95     // If the global address expression is a part of displacement field with a
  96     // register base, we should not emit any prefix symbol here, e.g.
  97     //   mov.w glb(r1), r2
  98     // Otherwise (!) msp430-as will silently miscompile the output :(
  99     if (!Modifier || strcmp(Modifier, "nohash"))
 100       O << '#';
 101     PrintSymbolOperand(MO, O);
 102     return;
 103   }
 104   }
 105 }
 106
 107 void MSP430AsmPrinter::printSrcMemOperand(const MachineInstr *MI, int OpNum,
 108                                           raw_ostream &O) {
 109   const MachineOperand &Base = MI->getOperand(OpNum);
 110   const MachineOperand &Disp = MI->getOperand(OpNum+1);
 111
 112   // Print displacement first
 113
 114   // Imm here is in fact global address - print extra modifier.
 115   if (Disp.isImm() && Base.getReg() == MSP430::SR)
 116     O << '&';
 117   printOperand(MI, OpNum+1, O, "nohash");
 118
 119   // Print register base field
 120   if (Base.getReg() != MSP430::SR && Base.getReg() != MSP430::PC) {
 121     O << '(';
 122     printOperand(MI, OpNum, O);
 123     O << ')';
 124   }
 125 }
 126
 127 /// PrintAsmOperand - Print out an operand for an inline asm expression.
 128 ///
 129 bool MSP430AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
 130                                        const char *ExtraCode, raw_ostream &O) {
 131   // Does this asm operand have a single letter operand modifier?
 132   if (ExtraCode && ExtraCode[0])
 133     return AsmPrinter::PrintAsmOperand(MI, OpNo, ExtraCode, O);
 134
 135   printOperand(MI, OpNo, O);
 136   return false;
 137 }
 138
 139 bool MSP430AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
 140                                              unsigned OpNo,
 141                                              const char *ExtraCode,
 142                                              raw_ostream &O) {
 143   if (ExtraCode && ExtraCode[0]) {
 144     return true; // Unknown modifier.
 145   }
 146   printSrcMemOperand(MI, OpNo, O);
 147   return false;
 148 }
 149
 150 //===----------------------------------------------------------------------===//
 151 void MSP430AsmPrinter::EmitInstruction(const MachineInstr *MI) {
 152   MSP430MCInstLower MCInstLowering(OutContext, *this);
 153
 154   MCInst TmpInst;
 155   MCInstLowering.Lower(MI, TmpInst);
 156   EmitToStreamer(*OutStreamer, TmpInst);
 157 }
 158
 159 void MSP430AsmPrinter::EmitInterruptVectorSection(MachineFunction &ISR) {
 160   MCSection *Cur = OutStreamer->getCurrentSectionOnly();
 161   const auto *F = &ISR.getFunction();
 162   assert(F->hasFnAttribute("interrupt") &&
 163          "Functions with MSP430_INTR CC should have 'interrupt' attribute");
 164   StringRef IVIdx = F->getFnAttribute("interrupt").getValueAsString();
 165   MCSection *IV = OutStreamer->getContext().getELFSection(
 166     "__interrupt_vector_" + IVIdx,
 167     ELF::SHT_PROGBITS, ELF::SHF_ALLOC | ELF::SHF_EXECINSTR);
 168   OutStreamer->SwitchSection(IV);
 169
 170   const MCSymbol *FunctionSymbol = getSymbol(F);
 171   OutStreamer->EmitSymbolValue(FunctionSymbol, TM.getProgramPointerSize());
 172   OutStreamer->SwitchSection(Cur);
 173 }
 174
 175 bool MSP430AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
 176   // Emit separate section for an interrupt vector if ISR
 177   if (MF.getFunction().getCallingConv() == CallingConv::MSP430_INTR)
 178     EmitInterruptVectorSection(MF);
 179
 180   SetupMachineFunction(MF);
 181   EmitFunctionBody();
 182   return false;
 183 }
 184
 185 // Force static initialization.
 186 extern "C" void LLVMInitializeMSP430AsmPrinter() {
 187   RegisterAsmPrinter<MSP430AsmPrinter> X(getTheMSP430Target());
 188 }