1 //===-- AVRAsmPrinter.cpp - AVR 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 GAS-format AVR assembly language.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "AVR.h"
15 #include "AVRMCInstLower.h"
16 #include "AVRSubtarget.h"
17 #include "MCTargetDesc/AVRInstPrinter.h"
18 #include "MCTargetDesc/AVRMCExpr.h"
19 #include "TargetInfo/AVRTargetInfo.h"
20
21 #include "llvm/CodeGen/AsmPrinter.h"
22 #include "llvm/CodeGen/MachineFunction.h"
23 #include "llvm/CodeGen/MachineInstr.h"
24 #include "llvm/CodeGen/TargetRegisterInfo.h"
25 #include "llvm/CodeGen/TargetSubtargetInfo.h"
26 #include "llvm/IR/Mangler.h"
27 #include "llvm/MC/MCInst.h"
28 #include "llvm/MC/MCStreamer.h"
29 #include "llvm/MC/MCSymbol.h"
30 #include "llvm/Support/ErrorHandling.h"
31 #include "llvm/Support/TargetRegistry.h"
32 #include "llvm/Support/raw_ostream.h"
33
34 #define DEBUG_TYPE "avr-asm-printer"
35
36 namespace llvm {
37
38 /// An AVR assembly code printer.
39 class AVRAsmPrinter : public AsmPrinter {
40 public:
AVRAsmPrinter(TargetMachine & TM,std::unique_ptr<MCStreamer> Streamer)41 AVRAsmPrinter(TargetMachine &TM,
42 std::unique_ptr<MCStreamer> Streamer)
43 : AsmPrinter(TM, std::move(Streamer)), MRI(*TM.getMCRegisterInfo()) { }
44
getPassName() const45 StringRef getPassName() const override { return "AVR Assembly Printer"; }
46
47 void printOperand(const MachineInstr *MI, unsigned OpNo, raw_ostream &O);
48
49 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
50 const char *ExtraCode, raw_ostream &O) override;
51
52 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
53 const char *ExtraCode, raw_ostream &O) override;
54
55 void emitInstruction(const MachineInstr *MI) override;
56
57 const MCExpr *lowerConstant(const Constant *CV) override;
58
59 private:
60 const MCRegisterInfo &MRI;
61 };
62
printOperand(const MachineInstr * MI,unsigned OpNo,raw_ostream & O)63 void AVRAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
64 raw_ostream &O) {
65 const MachineOperand &MO = MI->getOperand(OpNo);
66
67 switch (MO.getType()) {
68 case MachineOperand::MO_Register:
69 O << AVRInstPrinter::getPrettyRegisterName(MO.getReg(), MRI);
70 break;
71 case MachineOperand::MO_Immediate:
72 O << MO.getImm();
73 break;
74 case MachineOperand::MO_GlobalAddress:
75 O << getSymbol(MO.getGlobal());
76 break;
77 case MachineOperand::MO_ExternalSymbol:
78 O << *GetExternalSymbolSymbol(MO.getSymbolName());
79 break;
80 case MachineOperand::MO_MachineBasicBlock:
81 O << *MO.getMBB()->getSymbol();
82 break;
83 default:
84 llvm_unreachable("Not implemented yet!");
85 }
86 }
87
PrintAsmOperand(const MachineInstr * MI,unsigned OpNum,const char * ExtraCode,raw_ostream & O)88 bool AVRAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
89 const char *ExtraCode, raw_ostream &O) {
90 // Default asm printer can only deal with some extra codes,
91 // so try it first.
92 bool Error = AsmPrinter::PrintAsmOperand(MI, OpNum, ExtraCode, O);
93
94 if (Error && ExtraCode && ExtraCode[0]) {
95 if (ExtraCode[1] != 0)
96 return true; // Unknown modifier.
97
98 if (ExtraCode[0] >= 'A' && ExtraCode[0] <= 'Z') {
99 const MachineOperand &RegOp = MI->getOperand(OpNum);
100
101 assert(RegOp.isReg() && "Operand must be a register when you're"
102 "using 'A'..'Z' operand extracodes.");
103 Register Reg = RegOp.getReg();
104
105 unsigned ByteNumber = ExtraCode[0] - 'A';
106
107 unsigned OpFlags = MI->getOperand(OpNum - 1).getImm();
108 unsigned NumOpRegs = InlineAsm::getNumOperandRegisters(OpFlags);
109 (void)NumOpRegs;
110
111 const AVRSubtarget &STI = MF->getSubtarget<AVRSubtarget>();
112 const TargetRegisterInfo &TRI = *STI.getRegisterInfo();
113
114 const TargetRegisterClass *RC = TRI.getMinimalPhysRegClass(Reg);
115 unsigned BytesPerReg = TRI.getRegSizeInBits(*RC) / 8;
116 assert(BytesPerReg <= 2 && "Only 8 and 16 bit regs are supported.");
117
118 unsigned RegIdx = ByteNumber / BytesPerReg;
119 assert(RegIdx < NumOpRegs && "Multibyte index out of range.");
120
121 Reg = MI->getOperand(OpNum + RegIdx).getReg();
122
123 if (BytesPerReg == 2) {
124 Reg = TRI.getSubReg(Reg, ByteNumber % BytesPerReg ? AVR::sub_hi
125 : AVR::sub_lo);
126 }
127
128 O << AVRInstPrinter::getPrettyRegisterName(Reg, MRI);
129 return false;
130 }
131 }
132
133 if (Error)
134 printOperand(MI, OpNum, O);
135
136 return false;
137 }
138
PrintAsmMemoryOperand(const MachineInstr * MI,unsigned OpNum,const char * ExtraCode,raw_ostream & O)139 bool AVRAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
140 unsigned OpNum, const char *ExtraCode,
141 raw_ostream &O) {
142 if (ExtraCode && ExtraCode[0]) {
143 llvm_unreachable("This branch is not implemented yet");
144 }
145
146 const MachineOperand &MO = MI->getOperand(OpNum);
147 (void)MO;
148 assert(MO.isReg() && "Unexpected inline asm memory operand");
149
150 // TODO: We should be able to look up the alternative name for
151 // the register if it's given.
152 // TableGen doesn't expose a way of getting retrieving names
153 // for registers.
154 if (MI->getOperand(OpNum).getReg() == AVR::R31R30) {
155 O << "Z";
156 } else {
157 assert(MI->getOperand(OpNum).getReg() == AVR::R29R28 &&
158 "Wrong register class for memory operand.");
159 O << "Y";
160 }
161
162 // If NumOpRegs == 2, then we assume it is product of a FrameIndex expansion
163 // and the second operand is an Imm.
164 unsigned OpFlags = MI->getOperand(OpNum - 1).getImm();
165 unsigned NumOpRegs = InlineAsm::getNumOperandRegisters(OpFlags);
166
167 if (NumOpRegs == 2) {
168 O << '+' << MI->getOperand(OpNum + 1).getImm();
169 }
170
171 return false;
172 }
173
emitInstruction(const MachineInstr * MI)174 void AVRAsmPrinter::emitInstruction(const MachineInstr *MI) {
175 AVRMCInstLower MCInstLowering(OutContext, *this);
176
177 MCInst I;
178 MCInstLowering.lowerInstruction(*MI, I);
179 EmitToStreamer(*OutStreamer, I);
180 }
181
lowerConstant(const Constant * CV)182 const MCExpr *AVRAsmPrinter::lowerConstant(const Constant *CV) {
183 MCContext &Ctx = OutContext;
184
185 if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) {
186 bool IsProgMem = GV->getAddressSpace() == AVR::ProgramMemory;
187 if (IsProgMem) {
188 const MCExpr *Expr = MCSymbolRefExpr::create(getSymbol(GV), Ctx);
189 return AVRMCExpr::create(AVRMCExpr::VK_AVR_PM, Expr, false, Ctx);
190 }
191 }
192
193 return AsmPrinter::lowerConstant(CV);
194 }
195
196 } // end of namespace llvm
197
LLVMInitializeAVRAsmPrinter()198 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeAVRAsmPrinter() {
199 llvm::RegisterAsmPrinter<llvm::AVRAsmPrinter> X(llvm::getTheAVRTarget());
200 }
201
202