xref: /freebsd/contrib/llvm-project/llvm/lib/Target/SystemZ/SystemZMCInstLower.cpp (revision f81cdf24ba5436367377f7c8e8f51f6df2a75ca7)
1 //===-- SystemZMCInstLower.cpp - Lower MachineInstr to MCInst -------------===//
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 #include "SystemZMCInstLower.h"
10 #include "SystemZAsmPrinter.h"
11 #include "llvm/IR/Mangler.h"
12 #include "llvm/MC/MCExpr.h"
13 #include "llvm/MC/MCInst.h"
14 #include "llvm/MC/MCStreamer.h"
15 
16 using namespace llvm;
17 
18 // Return the VK_* enumeration for MachineOperand target flags Flags.
19 static MCSymbolRefExpr::VariantKind getVariantKind(unsigned Flags) {
20   switch (Flags & SystemZII::MO_SYMBOL_MODIFIER) {
21     case 0:
22       return MCSymbolRefExpr::VK_None;
23     case SystemZII::MO_GOT:
24       return MCSymbolRefExpr::VK_GOT;
25     case SystemZII::MO_INDNTPOFF:
26       return MCSymbolRefExpr::VK_INDNTPOFF;
27   }
28   llvm_unreachable("Unrecognised MO_ACCESS_MODEL");
29 }
30 
31 SystemZMCInstLower::SystemZMCInstLower(MCContext &ctx,
32                                        SystemZAsmPrinter &asmprinter)
33   : Ctx(ctx), AsmPrinter(asmprinter) {}
34 
35 const MCExpr *
36 SystemZMCInstLower::getExpr(const MachineOperand &MO,
37                             MCSymbolRefExpr::VariantKind Kind) const {
38   const MCSymbol *Symbol;
39   bool HasOffset = true;
40   switch (MO.getType()) {
41   case MachineOperand::MO_MachineBasicBlock:
42     Symbol = MO.getMBB()->getSymbol();
43     HasOffset = false;
44     break;
45 
46   case MachineOperand::MO_GlobalAddress:
47     Symbol = AsmPrinter.getSymbol(MO.getGlobal());
48     break;
49 
50   case MachineOperand::MO_ExternalSymbol:
51     Symbol = AsmPrinter.GetExternalSymbolSymbol(MO.getSymbolName());
52     break;
53 
54   case MachineOperand::MO_JumpTableIndex:
55     Symbol = AsmPrinter.GetJTISymbol(MO.getIndex());
56     HasOffset = false;
57     break;
58 
59   case MachineOperand::MO_ConstantPoolIndex:
60     Symbol = AsmPrinter.GetCPISymbol(MO.getIndex());
61     break;
62 
63   case MachineOperand::MO_BlockAddress:
64     Symbol = AsmPrinter.GetBlockAddressSymbol(MO.getBlockAddress());
65     break;
66 
67   default:
68     llvm_unreachable("unknown operand type");
69   }
70   const MCExpr *Expr = MCSymbolRefExpr::create(Symbol, Kind, Ctx);
71   if (HasOffset)
72     if (int64_t Offset = MO.getOffset()) {
73       const MCExpr *OffsetExpr = MCConstantExpr::create(Offset, Ctx);
74       Expr = MCBinaryExpr::createAdd(Expr, OffsetExpr, Ctx);
75     }
76   return Expr;
77 }
78 
79 MCOperand SystemZMCInstLower::lowerOperand(const MachineOperand &MO) const {
80   switch (MO.getType()) {
81   case MachineOperand::MO_Register:
82     return MCOperand::createReg(MO.getReg());
83 
84   case MachineOperand::MO_Immediate:
85     return MCOperand::createImm(MO.getImm());
86 
87   default: {
88     MCSymbolRefExpr::VariantKind Kind = getVariantKind(MO.getTargetFlags());
89     return MCOperand::createExpr(getExpr(MO, Kind));
90   }
91   }
92 }
93 
94 void SystemZMCInstLower::lower(const MachineInstr *MI, MCInst &OutMI) const {
95   OutMI.setOpcode(MI->getOpcode());
96   for (const MachineOperand &MO : MI->operands())
97     // Ignore all implicit register operands.
98     if (!MO.isReg() || !MO.isImplicit())
99       OutMI.addOperand(lowerOperand(MO));
100 }
101