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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:
MSP430AsmPrinter(TargetMachine & TM,std::unique_ptr<MCStreamer> Streamer)42     MSP430AsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
43         : AsmPrinter(TM, std::move(Streamer)) {}
44 
getPassName() const45     const char *getPassName() const override {
46       return "MSP430 Assembly Printer";
47     }
48 
49     void printOperand(const MachineInstr *MI, int OpNum,
50                       raw_ostream &O, const char* Modifier = nullptr);
51     void printSrcMemOperand(const MachineInstr *MI, int OpNum,
52                             raw_ostream &O);
53     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
54                          unsigned AsmVariant, const char *ExtraCode,
55                          raw_ostream &O) override;
56     bool PrintAsmMemoryOperand(const MachineInstr *MI,
57                                unsigned OpNo, unsigned AsmVariant,
58                                const char *ExtraCode, raw_ostream &O) override;
59     void EmitInstruction(const MachineInstr *MI) override;
60   };
61 } // end of anonymous namespace
62 
63 
printOperand(const MachineInstr * MI,int OpNum,raw_ostream & O,const char * Modifier)64 void MSP430AsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
65                                     raw_ostream &O, const char *Modifier) {
66   const MachineOperand &MO = MI->getOperand(OpNum);
67   switch (MO.getType()) {
68   default: llvm_unreachable("Not implemented yet!");
69   case MachineOperand::MO_Register:
70     O << MSP430InstPrinter::getRegisterName(MO.getReg());
71     return;
72   case MachineOperand::MO_Immediate:
73     if (!Modifier || strcmp(Modifier, "nohash"))
74       O << '#';
75     O << MO.getImm();
76     return;
77   case MachineOperand::MO_MachineBasicBlock:
78     MO.getMBB()->getSymbol()->print(O, MAI);
79     return;
80   case MachineOperand::MO_GlobalAddress: {
81     bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
82     uint64_t Offset = MO.getOffset();
83 
84     // If the global address expression is a part of displacement field with a
85     // register base, we should not emit any prefix symbol here, e.g.
86     //   mov.w &foo, r1
87     // vs
88     //   mov.w glb(r1), r2
89     // Otherwise (!) msp430-as will silently miscompile the output :(
90     if (!Modifier || strcmp(Modifier, "nohash"))
91       O << (isMemOp ? '&' : '#');
92     if (Offset)
93       O << '(' << Offset << '+';
94 
95     getSymbol(MO.getGlobal())->print(O, MAI);
96 
97     if (Offset)
98       O << ')';
99 
100     return;
101   }
102   }
103 }
104 
printSrcMemOperand(const MachineInstr * MI,int OpNum,raw_ostream & O)105 void MSP430AsmPrinter::printSrcMemOperand(const MachineInstr *MI, int OpNum,
106                                           raw_ostream &O) {
107   const MachineOperand &Base = MI->getOperand(OpNum);
108   const MachineOperand &Disp = MI->getOperand(OpNum+1);
109 
110   // Print displacement first
111 
112   // Imm here is in fact global address - print extra modifier.
113   if (Disp.isImm() && !Base.getReg())
114     O << '&';
115   printOperand(MI, OpNum+1, O, "nohash");
116 
117   // Print register base field
118   if (Base.getReg()) {
119     O << '(';
120     printOperand(MI, OpNum, O);
121     O << ')';
122   }
123 }
124 
125 /// PrintAsmOperand - Print out an operand for an inline asm expression.
126 ///
PrintAsmOperand(const MachineInstr * MI,unsigned OpNo,unsigned AsmVariant,const char * ExtraCode,raw_ostream & O)127 bool MSP430AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
128                                        unsigned AsmVariant,
129                                        const char *ExtraCode, raw_ostream &O) {
130   // Does this asm operand have a single letter operand modifier?
131   if (ExtraCode && ExtraCode[0])
132     return true; // Unknown modifier.
133 
134   printOperand(MI, OpNo, O);
135   return false;
136 }
137 
PrintAsmMemoryOperand(const MachineInstr * MI,unsigned OpNo,unsigned AsmVariant,const char * ExtraCode,raw_ostream & O)138 bool MSP430AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
139                                              unsigned OpNo, unsigned AsmVariant,
140                                              const char *ExtraCode,
141                                              raw_ostream &O) {
142   if (ExtraCode && ExtraCode[0]) {
143     return true; // Unknown modifier.
144   }
145   printSrcMemOperand(MI, OpNo, O);
146   return false;
147 }
148 
149 //===----------------------------------------------------------------------===//
EmitInstruction(const MachineInstr * MI)150 void MSP430AsmPrinter::EmitInstruction(const MachineInstr *MI) {
151   MSP430MCInstLower MCInstLowering(OutContext, *this);
152 
153   MCInst TmpInst;
154   MCInstLowering.Lower(MI, TmpInst);
155   EmitToStreamer(*OutStreamer, TmpInst);
156 }
157 
158 // Force static initialization.
LLVMInitializeMSP430AsmPrinter()159 extern "C" void LLVMInitializeMSP430AsmPrinter() {
160   RegisterAsmPrinter<MSP430AsmPrinter> X(TheMSP430Target);
161 }
162