1 //===-- MSP430AsmPrinter.cpp - MSP430 LLVM assembly writer ----------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains a printer that converts from our internal representation
11 // of machine-dependent LLVM code to the MSP430 assembly language.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "MSP430.h"
16 #include "InstPrinter/MSP430InstPrinter.h"
17 #include "MSP430InstrInfo.h"
18 #include "MSP430MCInstLower.h"
19 #include "MSP430TargetMachine.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/MCStreamer.h"
32 #include "llvm/MC/MCSymbol.h"
33 #include "llvm/Support/TargetRegistry.h"
34 #include "llvm/Support/raw_ostream.h"
35 using namespace llvm;
36 
37 #define DEBUG_TYPE "asm-printer"
38 
39 namespace {
40   class MSP430AsmPrinter : public AsmPrinter {
41   public:
42     MSP430AsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
43         : AsmPrinter(TM, std::move(Streamer)) {}
44 
45     StringRef getPassName() const override { return "MSP430 Assembly Printer"; }
46 
47     void printOperand(const MachineInstr *MI, int OpNum,
48                       raw_ostream &O, const char* Modifier = nullptr);
49     void printSrcMemOperand(const MachineInstr *MI, int OpNum,
50                             raw_ostream &O);
51     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
52                          unsigned AsmVariant, const char *ExtraCode,
53                          raw_ostream &O) override;
54     bool PrintAsmMemoryOperand(const MachineInstr *MI,
55                                unsigned OpNo, unsigned AsmVariant,
56                                const char *ExtraCode, raw_ostream &O) override;
57     void EmitInstruction(const MachineInstr *MI) override;
58   };
59 } // end of anonymous namespace
60 
61 
62 void MSP430AsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
63                                     raw_ostream &O, const char *Modifier) {
64   const MachineOperand &MO = MI->getOperand(OpNum);
65   switch (MO.getType()) {
66   default: llvm_unreachable("Not implemented yet!");
67   case MachineOperand::MO_Register:
68     O << MSP430InstPrinter::getRegisterName(MO.getReg());
69     return;
70   case MachineOperand::MO_Immediate:
71     if (!Modifier || strcmp(Modifier, "nohash"))
72       O << '#';
73     O << MO.getImm();
74     return;
75   case MachineOperand::MO_MachineBasicBlock:
76     MO.getMBB()->getSymbol()->print(O, MAI);
77     return;
78   case MachineOperand::MO_GlobalAddress: {
79     bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
80     uint64_t Offset = MO.getOffset();
81 
82     // If the global address expression is a part of displacement field with a
83     // register base, we should not emit any prefix symbol here, e.g.
84     //   mov.w &foo, r1
85     // vs
86     //   mov.w glb(r1), r2
87     // Otherwise (!) msp430-as will silently miscompile the output :(
88     if (!Modifier || strcmp(Modifier, "nohash"))
89       O << (isMemOp ? '&' : '#');
90     if (Offset)
91       O << '(' << Offset << '+';
92 
93     getSymbol(MO.getGlobal())->print(O, MAI);
94 
95     if (Offset)
96       O << ')';
97 
98     return;
99   }
100   }
101 }
102 
103 void MSP430AsmPrinter::printSrcMemOperand(const MachineInstr *MI, int OpNum,
104                                           raw_ostream &O) {
105   const MachineOperand &Base = MI->getOperand(OpNum);
106   const MachineOperand &Disp = MI->getOperand(OpNum+1);
107 
108   // Print displacement first
109 
110   // Imm here is in fact global address - print extra modifier.
111   if (Disp.isImm() && !Base.getReg())
112     O << '&';
113   printOperand(MI, OpNum+1, O, "nohash");
114 
115   // Print register base field
116   if (Base.getReg()) {
117     O << '(';
118     printOperand(MI, OpNum, O);
119     O << ')';
120   }
121 }
122 
123 /// PrintAsmOperand - Print out an operand for an inline asm expression.
124 ///
125 bool MSP430AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
126                                        unsigned AsmVariant,
127                                        const char *ExtraCode, raw_ostream &O) {
128   // Does this asm operand have a single letter operand modifier?
129   if (ExtraCode && ExtraCode[0])
130     return true; // Unknown modifier.
131 
132   printOperand(MI, OpNo, O);
133   return false;
134 }
135 
136 bool MSP430AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
137                                              unsigned OpNo, unsigned AsmVariant,
138                                              const char *ExtraCode,
139                                              raw_ostream &O) {
140   if (ExtraCode && ExtraCode[0]) {
141     return true; // Unknown modifier.
142   }
143   printSrcMemOperand(MI, OpNo, O);
144   return false;
145 }
146 
147 //===----------------------------------------------------------------------===//
148 void MSP430AsmPrinter::EmitInstruction(const MachineInstr *MI) {
149   MSP430MCInstLower MCInstLowering(OutContext, *this);
150 
151   MCInst TmpInst;
152   MCInstLowering.Lower(MI, TmpInst);
153   EmitToStreamer(*OutStreamer, TmpInst);
154 }
155 
156 // Force static initialization.
157 extern "C" void LLVMInitializeMSP430AsmPrinter() {
158   RegisterAsmPrinter<MSP430AsmPrinter> X(getTheMSP430Target());
159 }
160