1 //===- AMDGPUMCInstLower.h - Lower AMDGPU MachineInstr to an 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 /// \file
10 /// Header of lower AMDGPU MachineInstrs to their corresponding MCInst.
11 //
12 //===----------------------------------------------------------------------===//
13 //
14 
15 #ifndef LLVM_LIB_TARGET_AMDGPU_AMDGPUMCINSTLOWER_H
16 #define LLVM_LIB_TARGET_AMDGPU_AMDGPUMCINSTLOWER_H
17 
18 #include "AMDGPUTargetMachine.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/Support/Casting.h"
21 
22 namespace llvm {
23 class AsmPrinter;
24 class MCContext;
25 } // namespace llvm
26 
27 using namespace llvm;
28 
29 class AMDGPUMCInstLower {
30   MCContext &Ctx;
31   const TargetSubtargetInfo &ST;
32   const AsmPrinter ≈
33 
34 public:
35   AMDGPUMCInstLower(MCContext &ctx, const TargetSubtargetInfo &ST,
36                     const AsmPrinter &AP);
37 
38   bool lowerOperand(const MachineOperand &MO, MCOperand &MCOp) const;
39 
40   /// Lower a MachineInstr to an MCInst
41   void lower(const MachineInstr *MI, MCInst &OutMI) const;
42 };
43 
44 namespace {
45 static inline const MCExpr *lowerAddrSpaceCast(const TargetMachine &TM,
46                                                const Constant *CV,
47                                                MCContext &OutContext) {
48   // TargetMachine does not support llvm-style cast. Use C++-style cast.
49   // This is safe since TM is always of type AMDGPUTargetMachine or its
50   // derived class.
51   auto &AT = static_cast<const AMDGPUTargetMachine &>(TM);
52   auto *CE = dyn_cast<ConstantExpr>(CV);
53 
54   // Lower null pointers in private and local address space.
55   // Clang generates addrspacecast for null pointers in private and local
56   // address space, which needs to be lowered.
57   if (CE && CE->getOpcode() == Instruction::AddrSpaceCast) {
58     auto Op = CE->getOperand(0);
59     auto SrcAddr = Op->getType()->getPointerAddressSpace();
60     if (Op->isNullValue() && AT.getNullPointerValue(SrcAddr) == 0) {
61       auto DstAddr = CE->getType()->getPointerAddressSpace();
62       return MCConstantExpr::create(AT.getNullPointerValue(DstAddr),
63                                     OutContext);
64     }
65   }
66   return nullptr;
67 }
68 } // namespace
69 #endif // LLVM_LIB_TARGET_AMDGPU_AMDGPUMCINSTLOWER_H
70