1 //===-- MBlazeAsmBackend.cpp - MBlaze Assembler Backend -------------------===//
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 #include "MCTargetDesc/MBlazeMCTargetDesc.h"
11 #include "llvm/MC/MCAsmBackend.h"
12 #include "llvm/MC/MCAssembler.h"
13 #include "llvm/MC/MCAsmLayout.h"
14 #include "llvm/MC/MCELFObjectWriter.h"
15 #include "llvm/MC/MCELFSymbolFlags.h"
16 #include "llvm/MC/MCExpr.h"
17 #include "llvm/MC/MCObjectWriter.h"
18 #include "llvm/MC/MCSectionELF.h"
19 #include "llvm/MC/MCSectionMachO.h"
20 #include "llvm/MC/MCValue.h"
21 #include "llvm/ADT/Twine.h"
22 #include "llvm/Support/ELF.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/TargetRegistry.h"
25 #include "llvm/Support/raw_ostream.h"
26 using namespace llvm;
27
getFixupKindSize(unsigned Kind)28 static unsigned getFixupKindSize(unsigned Kind) {
29 switch (Kind) {
30 default: assert(0 && "invalid fixup kind!");
31 case FK_Data_1: return 1;
32 case FK_PCRel_2:
33 case FK_Data_2: return 2;
34 case FK_PCRel_4:
35 case FK_Data_4: return 4;
36 case FK_Data_8: return 8;
37 }
38 }
39
40
41 namespace {
42 class MBlazeELFObjectWriter : public MCELFObjectTargetWriter {
43 public:
MBlazeELFObjectWriter(Triple::OSType OSType)44 MBlazeELFObjectWriter(Triple::OSType OSType)
45 : MCELFObjectTargetWriter(/*is64Bit*/ false, OSType, ELF::EM_MBLAZE,
46 /*HasRelocationAddend*/ true) {}
47 };
48
49 class MBlazeAsmBackend : public MCAsmBackend {
50 public:
MBlazeAsmBackend(const Target & T)51 MBlazeAsmBackend(const Target &T)
52 : MCAsmBackend() {
53 }
54
getNumFixupKinds() const55 unsigned getNumFixupKinds() const {
56 return 2;
57 }
58
59 bool MayNeedRelaxation(const MCInst &Inst) const;
60
61 void RelaxInstruction(const MCInst &Inst, MCInst &Res) const;
62
63 bool WriteNopData(uint64_t Count, MCObjectWriter *OW) const;
64
getPointerSize() const65 unsigned getPointerSize() const {
66 return 4;
67 }
68 };
69
getRelaxedOpcode(unsigned Op)70 static unsigned getRelaxedOpcode(unsigned Op) {
71 switch (Op) {
72 default: return Op;
73 case MBlaze::ADDIK: return MBlaze::ADDIK32;
74 case MBlaze::ORI: return MBlaze::ORI32;
75 case MBlaze::BRLID: return MBlaze::BRLID32;
76 }
77 }
78
MayNeedRelaxation(const MCInst & Inst) const79 bool MBlazeAsmBackend::MayNeedRelaxation(const MCInst &Inst) const {
80 if (getRelaxedOpcode(Inst.getOpcode()) == Inst.getOpcode())
81 return false;
82
83 bool hasExprOrImm = false;
84 for (unsigned i = 0; i < Inst.getNumOperands(); ++i)
85 hasExprOrImm |= Inst.getOperand(i).isExpr();
86
87 return hasExprOrImm;
88 }
89
RelaxInstruction(const MCInst & Inst,MCInst & Res) const90 void MBlazeAsmBackend::RelaxInstruction(const MCInst &Inst, MCInst &Res) const {
91 Res = Inst;
92 Res.setOpcode(getRelaxedOpcode(Inst.getOpcode()));
93 }
94
WriteNopData(uint64_t Count,MCObjectWriter * OW) const95 bool MBlazeAsmBackend::WriteNopData(uint64_t Count, MCObjectWriter *OW) const {
96 if ((Count % 4) != 0)
97 return false;
98
99 for (uint64_t i = 0; i < Count; i += 4)
100 OW->Write32(0x00000000);
101
102 return true;
103 }
104 } // end anonymous namespace
105
106 namespace {
107 class ELFMBlazeAsmBackend : public MBlazeAsmBackend {
108 public:
109 Triple::OSType OSType;
ELFMBlazeAsmBackend(const Target & T,Triple::OSType _OSType)110 ELFMBlazeAsmBackend(const Target &T, Triple::OSType _OSType)
111 : MBlazeAsmBackend(T), OSType(_OSType) { }
112
113 void ApplyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize,
114 uint64_t Value) const;
115
createObjectWriter(raw_ostream & OS) const116 MCObjectWriter *createObjectWriter(raw_ostream &OS) const {
117 return createELFObjectWriter(new MBlazeELFObjectWriter(OSType), OS,
118 /*IsLittleEndian*/ false);
119 }
120 };
121
ApplyFixup(const MCFixup & Fixup,char * Data,unsigned DataSize,uint64_t Value) const122 void ELFMBlazeAsmBackend::ApplyFixup(const MCFixup &Fixup, char *Data,
123 unsigned DataSize, uint64_t Value) const {
124 unsigned Size = getFixupKindSize(Fixup.getKind());
125
126 assert(Fixup.getOffset() + Size <= DataSize &&
127 "Invalid fixup offset!");
128
129 char *data = Data + Fixup.getOffset();
130 switch (Size) {
131 default: llvm_unreachable("Cannot fixup unknown value.");
132 case 1: llvm_unreachable("Cannot fixup 1 byte value.");
133 case 8: llvm_unreachable("Cannot fixup 8 byte value.");
134
135 case 4:
136 *(data+7) = uint8_t(Value);
137 *(data+6) = uint8_t(Value >> 8);
138 *(data+3) = uint8_t(Value >> 16);
139 *(data+2) = uint8_t(Value >> 24);
140 break;
141
142 case 2:
143 *(data+3) = uint8_t(Value >> 0);
144 *(data+2) = uint8_t(Value >> 8);
145 }
146 }
147 } // end anonymous namespace
148
createMBlazeAsmBackend(const Target & T,StringRef TT)149 MCAsmBackend *llvm::createMBlazeAsmBackend(const Target &T, StringRef TT) {
150 Triple TheTriple(TT);
151
152 if (TheTriple.isOSDarwin())
153 assert(0 && "Mac not supported on MBlaze");
154
155 if (TheTriple.isOSWindows())
156 assert(0 && "Windows not supported on MBlaze");
157
158 return new ELFMBlazeAsmBackend(T, TheTriple.getOS());
159 }
160