1 //===- R600MCCodeEmitter.cpp - Code Emitter for R600->Cayman GPU families -===//
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 ///
11 /// The R600 code emitter produces machine code that can be executed
12 /// directly on the GPU device.
13 //
14 //===----------------------------------------------------------------------===//
15
16 #include "MCTargetDesc/R600MCTargetDesc.h"
17 #include "R600Defines.h"
18 #include "llvm/MC/MCCodeEmitter.h"
19 #include "llvm/MC/MCContext.h"
20 #include "llvm/MC/MCInst.h"
21 #include "llvm/MC/MCInstrInfo.h"
22 #include "llvm/MC/MCRegisterInfo.h"
23 #include "llvm/MC/MCSubtargetInfo.h"
24 #include "llvm/Support/EndianStream.h"
25 #include "llvm/TargetParser/SubtargetFeature.h"
26
27 using namespace llvm;
28
29 namespace {
30
31 class R600MCCodeEmitter : public MCCodeEmitter {
32 const MCRegisterInfo &MRI;
33 const MCInstrInfo &MCII;
34
35 public:
R600MCCodeEmitter(const MCInstrInfo & mcii,const MCRegisterInfo & mri)36 R600MCCodeEmitter(const MCInstrInfo &mcii, const MCRegisterInfo &mri)
37 : MRI(mri), MCII(mcii) {}
38 R600MCCodeEmitter(const R600MCCodeEmitter &) = delete;
39 R600MCCodeEmitter &operator=(const R600MCCodeEmitter &) = delete;
40
41 /// Encode the instruction and write it to the OS.
42 void encodeInstruction(const MCInst &MI, SmallVectorImpl<char> &CB,
43 SmallVectorImpl<MCFixup> &Fixups,
44 const MCSubtargetInfo &STI) const override;
45
46 /// \returns the encoding for an MCOperand.
47 uint64_t getMachineOpValue(const MCInst &MI, const MCOperand &MO,
48 SmallVectorImpl<MCFixup> &Fixups,
49 const MCSubtargetInfo &STI) const;
50
51 private:
52 void emit(uint32_t value, SmallVectorImpl<char> &CB) const;
53 void emit(uint64_t value, SmallVectorImpl<char> &CB) const;
54
55 unsigned getHWReg(unsigned regNo) const;
56
57 uint64_t getBinaryCodeForInstr(const MCInst &MI,
58 SmallVectorImpl<MCFixup> &Fixups,
59 const MCSubtargetInfo &STI) const;
60 };
61
62 } // end anonymous namespace
63
64 enum RegElement {
65 ELEMENT_X = 0,
66 ELEMENT_Y,
67 ELEMENT_Z,
68 ELEMENT_W
69 };
70
71 enum FCInstr {
72 FC_IF_PREDICATE = 0,
73 FC_ELSE,
74 FC_ENDIF,
75 FC_BGNLOOP,
76 FC_ENDLOOP,
77 FC_BREAK_PREDICATE,
78 FC_CONTINUE
79 };
80
createR600MCCodeEmitter(const MCInstrInfo & MCII,MCContext & Ctx)81 MCCodeEmitter *llvm::createR600MCCodeEmitter(const MCInstrInfo &MCII,
82 MCContext &Ctx) {
83 return new R600MCCodeEmitter(MCII, *Ctx.getRegisterInfo());
84 }
85
encodeInstruction(const MCInst & MI,SmallVectorImpl<char> & CB,SmallVectorImpl<MCFixup> & Fixups,const MCSubtargetInfo & STI) const86 void R600MCCodeEmitter::encodeInstruction(const MCInst &MI,
87 SmallVectorImpl<char> &CB,
88 SmallVectorImpl<MCFixup> &Fixups,
89 const MCSubtargetInfo &STI) const {
90 const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
91 if (MI.getOpcode() == R600::RETURN ||
92 MI.getOpcode() == R600::FETCH_CLAUSE ||
93 MI.getOpcode() == R600::ALU_CLAUSE ||
94 MI.getOpcode() == R600::BUNDLE ||
95 MI.getOpcode() == R600::KILL) {
96 return;
97 }
98 if (IS_VTX(Desc)) {
99 uint64_t InstWord01 = getBinaryCodeForInstr(MI, Fixups, STI);
100 uint32_t InstWord2 = MI.getOperand(2).getImm(); // Offset
101 if (!(STI.hasFeature(R600::FeatureCaymanISA))) {
102 InstWord2 |= 1 << 19; // Mega-Fetch bit
103 }
104
105 emit(InstWord01, CB);
106 emit(InstWord2, CB);
107 emit((uint32_t)0, CB);
108 } else if (IS_TEX(Desc)) {
109 int64_t Sampler = MI.getOperand(14).getImm();
110
111 int64_t SrcSelect[4] = {
112 MI.getOperand(2).getImm(), MI.getOperand(3).getImm(),
113 MI.getOperand(4).getImm(), MI.getOperand(5).getImm()};
114 int64_t Offsets[3] = {MI.getOperand(6).getImm() & 0x1F,
115 MI.getOperand(7).getImm() & 0x1F,
116 MI.getOperand(8).getImm() & 0x1F};
117
118 uint64_t Word01 = getBinaryCodeForInstr(MI, Fixups, STI);
119 uint32_t Word2 = Sampler << 15 | SrcSelect[ELEMENT_X] << 20 |
120 SrcSelect[ELEMENT_Y] << 23 | SrcSelect[ELEMENT_Z] << 26 |
121 SrcSelect[ELEMENT_W] << 29 | Offsets[0] << 0 |
122 Offsets[1] << 5 | Offsets[2] << 10;
123
124 emit(Word01, CB);
125 emit(Word2, CB);
126 emit((uint32_t)0, CB);
127 } else {
128 uint64_t Inst = getBinaryCodeForInstr(MI, Fixups, STI);
129 if ((STI.hasFeature(R600::FeatureR600ALUInst)) &&
130 ((Desc.TSFlags & R600_InstFlag::OP1) ||
131 Desc.TSFlags & R600_InstFlag::OP2)) {
132 uint64_t ISAOpCode = Inst & (0x3FFULL << 39);
133 Inst &= ~(0x3FFULL << 39);
134 Inst |= ISAOpCode << 1;
135 }
136 emit(Inst, CB);
137 }
138 }
139
emit(uint32_t Value,SmallVectorImpl<char> & CB) const140 void R600MCCodeEmitter::emit(uint32_t Value, SmallVectorImpl<char> &CB) const {
141 support::endian::write(CB, Value, llvm::endianness::little);
142 }
143
emit(uint64_t Value,SmallVectorImpl<char> & CB) const144 void R600MCCodeEmitter::emit(uint64_t Value, SmallVectorImpl<char> &CB) const {
145 support::endian::write(CB, Value, llvm::endianness::little);
146 }
147
getHWReg(unsigned RegNo) const148 unsigned R600MCCodeEmitter::getHWReg(unsigned RegNo) const {
149 return MRI.getEncodingValue(RegNo) & HW_REG_MASK;
150 }
151
getMachineOpValue(const MCInst & MI,const MCOperand & MO,SmallVectorImpl<MCFixup> & Fixups,const MCSubtargetInfo & STI) const152 uint64_t R600MCCodeEmitter::getMachineOpValue(const MCInst &MI,
153 const MCOperand &MO,
154 SmallVectorImpl<MCFixup> &Fixups,
155 const MCSubtargetInfo &STI) const {
156 if (MO.isReg()) {
157 if (HAS_NATIVE_OPERANDS(MCII.get(MI.getOpcode()).TSFlags))
158 return MRI.getEncodingValue(MO.getReg());
159 return getHWReg(MO.getReg());
160 }
161
162 if (MO.isExpr()) {
163 // We put rodata at the end of code section, then map the entire
164 // code secetion as vtx buf. Thus the section relative address is the
165 // correct one.
166 // Each R600 literal instruction has two operands
167 // We can't easily get the order of the current one, so compare against
168 // the first one and adjust offset.
169 const unsigned offset = (&MO == &MI.getOperand(0)) ? 0 : 4;
170 Fixups.push_back(MCFixup::create(offset, MO.getExpr(), FK_SecRel_4, MI.getLoc()));
171 return 0;
172 }
173
174 assert(MO.isImm());
175 return MO.getImm();
176 }
177
178 #include "R600GenMCCodeEmitter.inc"
179