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/MC/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   if (F->getCallingConv() != CallingConv::MSP430_INTR) {
163     report_fatal_error("Functions with 'interrupt' attribute must have msp430_intrcc CC");
164   }
165   StringRef IVIdx = F->getFnAttribute("interrupt").getValueAsString();
166   MCSection *IV = OutStreamer->getContext().getELFSection(
167     "__interrupt_vector_" + IVIdx,
168     ELF::SHT_PROGBITS, ELF::SHF_ALLOC | ELF::SHF_EXECINSTR);
169   OutStreamer->switchSection(IV);
170 
171   const MCSymbol *FunctionSymbol = getSymbol(F);
172   OutStreamer->emitSymbolValue(FunctionSymbol, TM.getProgramPointerSize());
173   OutStreamer->switchSection(Cur);
174 }
175 
176 bool MSP430AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
177   // Emit separate section for an interrupt vector if ISR
178   if (MF.getFunction().hasFnAttribute("interrupt")) {
179     EmitInterruptVectorSection(MF);
180   }
181 
182   SetupMachineFunction(MF);
183   emitFunctionBody();
184   return false;
185 }
186 
187 // Force static initialization.
188 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeMSP430AsmPrinter() {
189   RegisterAsmPrinter<MSP430AsmPrinter> X(getTheMSP430Target());
190 }
191