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 "InstPrinter/MSP430InstPrinter.h"
  15 #include "MSP430.h"
  16 #include "MSP430InstrInfo.h"
  17 #include "MSP430MCInstLower.h"
  18 #include "MSP430TargetMachine.h"
  19 #include "llvm/BinaryFormat/ELF.h"
  20 #include "llvm/CodeGen/AsmPrinter.h"
  21 #include "llvm/CodeGen/MachineConstantPool.h"
  22 #include "llvm/CodeGen/MachineFunctionPass.h"
  23 #include "llvm/CodeGen/MachineInstr.h"
  24 #include "llvm/CodeGen/MachineModuleInfo.h"
  25 #include "llvm/IR/Constants.h"
  26 #include "llvm/IR/DerivedTypes.h"
  27 #include "llvm/IR/Mangler.h"
  28 #include "llvm/IR/Module.h"
  29 #include "llvm/MC/MCAsmInfo.h"
  30 #include "llvm/MC/MCInst.h"
  31 #include "llvm/MC/MCSectionELF.h"
  32 #include "llvm/MC/MCStreamer.h"
  33 #include "llvm/MC/MCSymbol.h"
  34 #include "llvm/Support/TargetRegistry.h"
  35 #include "llvm/Support/raw_ostream.h"
  36 using namespace llvm;
  37
  38 #define DEBUG_TYPE "asm-printer"
  39
  40 namespace {
  41   class MSP430AsmPrinter : public AsmPrinter {
  42   public:
  43     MSP430AsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
  44         : AsmPrinter(TM, std::move(Streamer)) {}
  45
  46     StringRef getPassName() const override { return "MSP430 Assembly Printer"; }
  47
  48     bool runOnMachineFunction(MachineFunction &MF) override;
  49
  50     void printOperand(const MachineInstr *MI, int OpNum,
  51                       raw_ostream &O, const char* Modifier = nullptr);
  52     void printSrcMemOperand(const MachineInstr *MI, int OpNum,
  53                             raw_ostream &O);
  54     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
  55                          unsigned AsmVariant, const char *ExtraCode,
  56                          raw_ostream &O) override;
  57     bool PrintAsmMemoryOperand(const MachineInstr *MI,
  58                                unsigned OpNo, unsigned AsmVariant,
  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
  67 void MSP430AsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
  68                                     raw_ostream &O, const char *Modifier) {
  69   const MachineOperand &MO = MI->getOperand(OpNum);
  70   switch (MO.getType()) {
  71   default: llvm_unreachable("Not implemented yet!");
  72   case MachineOperand::MO_Register:
  73     O << MSP430InstPrinter::getRegisterName(MO.getReg());
  74     return;
  75   case MachineOperand::MO_Immediate:
  76     if (!Modifier || strcmp(Modifier, "nohash"))
  77       O << '#';
  78     O << MO.getImm();
  79     return;
  80   case MachineOperand::MO_MachineBasicBlock:
  81     MO.getMBB()->getSymbol()->print(O, MAI);
  82     return;
  83   case MachineOperand::MO_GlobalAddress: {
  84     bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
  85     uint64_t Offset = MO.getOffset();
  86
  87     // If the global address expression is a part of displacement field with a
  88     // register base, we should not emit any prefix symbol here, e.g.
  89     //   mov.w &foo, r1
  90     // vs
  91     //   mov.w glb(r1), r2
  92     // Otherwise (!) msp430-as will silently miscompile the output :(
  93     if (!Modifier || strcmp(Modifier, "nohash"))
  94       O << (isMemOp ? '&' : '#');
  95     if (Offset)
  96       O << '(' << Offset << '+';
  97
  98     getSymbol(MO.getGlobal())->print(O, MAI);
  99
 100     if (Offset)
 101       O << ')';
 102
 103     return;
 104   }
 105   }
 106 }
 107
 108 void MSP430AsmPrinter::printSrcMemOperand(const MachineInstr *MI, int OpNum,
 109                                           raw_ostream &O) {
 110   const MachineOperand &Base = MI->getOperand(OpNum);
 111   const MachineOperand &Disp = MI->getOperand(OpNum+1);
 112
 113   // Print displacement first
 114
 115   // Imm here is in fact global address - print extra modifier.
 116   if (Disp.isImm() && Base.getReg() == MSP430::SR)
 117     O << '&';
 118   printOperand(MI, OpNum+1, O, "nohash");
 119
 120   // Print register base field
 121   if (Base.getReg() != MSP430::SR && Base.getReg() != MSP430::PC) {
 122     O << '(';
 123     printOperand(MI, OpNum, O);
 124     O << ')';
 125   }
 126 }
 127
 128 /// PrintAsmOperand - Print out an operand for an inline asm expression.
 129 ///
 130 bool MSP430AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
 131                                        unsigned AsmVariant,
 132                                        const char *ExtraCode, raw_ostream &O) {
 133   // Does this asm operand have a single letter operand modifier?
 134   if (ExtraCode && ExtraCode[0])
 135     return true; // Unknown modifier.
 136
 137   printOperand(MI, OpNo, O);
 138   return false;
 139 }
 140
 141 bool MSP430AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
 142                                              unsigned OpNo, unsigned AsmVariant,
 143                                              const char *ExtraCode,
 144                                              raw_ostream &O) {
 145   if (ExtraCode && ExtraCode[0]) {
 146     return true; // Unknown modifier.
 147   }
 148   printSrcMemOperand(MI, OpNo, O);
 149   return false;
 150 }
 151
 152 //===----------------------------------------------------------------------===//
 153 void MSP430AsmPrinter::EmitInstruction(const MachineInstr *MI) {
 154   MSP430MCInstLower MCInstLowering(OutContext, *this);
 155
 156   MCInst TmpInst;
 157   MCInstLowering.Lower(MI, TmpInst);
 158   EmitToStreamer(*OutStreamer, TmpInst);
 159 }
 160
 161 void MSP430AsmPrinter::EmitInterruptVectorSection(MachineFunction &ISR) {
 162   MCSection *Cur = OutStreamer->getCurrentSectionOnly();
 163   const auto *F = &ISR.getFunction();
 164   assert(F->hasFnAttribute("interrupt") &&
 165          "Functions with MSP430_INTR CC should have 'interrupt' attribute");
 166   StringRef IVIdx = F->getFnAttribute("interrupt").getValueAsString();
 167   MCSection *IV = OutStreamer->getContext().getELFSection(
 168     "__interrupt_vector_" + IVIdx,
 169     ELF::SHT_PROGBITS, ELF::SHF_ALLOC | ELF::SHF_EXECINSTR);
 170   OutStreamer->SwitchSection(IV);
 171
 172   const MCSymbol *FunctionSymbol = getSymbol(F);
 173   OutStreamer->EmitSymbolValue(FunctionSymbol, TM.getProgramPointerSize());
 174   OutStreamer->SwitchSection(Cur);
 175 }
 176
 177 bool MSP430AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
 178   // Emit separate section for an interrupt vector if ISR
 179   if (MF.getFunction().getCallingConv() == CallingConv::MSP430_INTR)
 180     EmitInterruptVectorSection(MF);
 181
 182   SetupMachineFunction(MF);
 183   EmitFunctionBody();
 184   return false;
 185 }
 186
 187 // Force static initialization.
 188 extern "C" void LLVMInitializeMSP430AsmPrinter() {
 189   RegisterAsmPrinter<MSP430AsmPrinter> X(getTheMSP430Target());
 190 }