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
26 using namespace llvm;
27
28 namespace {
29
30 class R600MCCodeEmitter : public MCCodeEmitter {
31 const MCRegisterInfo &MRI;
32 const MCInstrInfo &MCII;
33
34 public:
R600MCCodeEmitter(const MCInstrInfo & mcii,const MCRegisterInfo & mri)35 R600MCCodeEmitter(const MCInstrInfo &mcii, const MCRegisterInfo &mri)
36 : MRI(mri), MCII(mcii) {}
37 R600MCCodeEmitter(const R600MCCodeEmitter &) = delete;
38 R600MCCodeEmitter &operator=(const R600MCCodeEmitter &) = delete;
39
40 /// Encode the instruction and write it to the OS.
41 void encodeInstruction(const MCInst &MI, SmallVectorImpl<char> &CB,
42 SmallVectorImpl<MCFixup> &Fixups,
43 const MCSubtargetInfo &STI) const override;
44
45 /// \returns the encoding for an MCOperand.
46 uint64_t getMachineOpValue(const MCInst &MI, const MCOperand &MO,
47 SmallVectorImpl<MCFixup> &Fixups,
48 const MCSubtargetInfo &STI) const;
49
50 private:
51 void emit(uint32_t value, SmallVectorImpl<char> &CB) const;
52 void emit(uint64_t value, SmallVectorImpl<char> &CB) const;
53
54 unsigned getHWReg(MCRegister Reg) const;
55
56 uint64_t getBinaryCodeForInstr(const MCInst &MI,
57 SmallVectorImpl<MCFixup> &Fixups,
58 const MCSubtargetInfo &STI) const;
59 };
60
61 } // end anonymous namespace
62
63 enum RegElement {
64 ELEMENT_X = 0,
65 ELEMENT_Y,
66 ELEMENT_Z,
67 ELEMENT_W
68 };
69
70 enum FCInstr {
71 FC_IF_PREDICATE = 0,
72 FC_ELSE,
73 FC_ENDIF,
74 FC_BGNLOOP,
75 FC_ENDLOOP,
76 FC_BREAK_PREDICATE,
77 FC_CONTINUE
78 };
79
createR600MCCodeEmitter(const MCInstrInfo & MCII,MCContext & Ctx)80 MCCodeEmitter *llvm::createR600MCCodeEmitter(const MCInstrInfo &MCII,
81 MCContext &Ctx) {
82 return new R600MCCodeEmitter(MCII, *Ctx.getRegisterInfo());
83 }
84
encodeInstruction(const MCInst & MI,SmallVectorImpl<char> & CB,SmallVectorImpl<MCFixup> & Fixups,const MCSubtargetInfo & STI) const85 void R600MCCodeEmitter::encodeInstruction(const MCInst &MI,
86 SmallVectorImpl<char> &CB,
87 SmallVectorImpl<MCFixup> &Fixups,
88 const MCSubtargetInfo &STI) const {
89 const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
90 if (MI.getOpcode() == R600::RETURN ||
91 MI.getOpcode() == R600::FETCH_CLAUSE ||
92 MI.getOpcode() == R600::ALU_CLAUSE ||
93 MI.getOpcode() == R600::BUNDLE ||
94 MI.getOpcode() == R600::KILL) {
95 return;
96 }
97 if (IS_VTX(Desc)) {
98 uint64_t InstWord01 = getBinaryCodeForInstr(MI, Fixups, STI);
99 uint32_t InstWord2 = MI.getOperand(2).getImm(); // Offset
100 if (!(STI.hasFeature(R600::FeatureCaymanISA))) {
101 InstWord2 |= 1 << 19; // Mega-Fetch bit
102 }
103
104 emit(InstWord01, CB);
105 emit(InstWord2, CB);
106 emit((uint32_t)0, CB);
107 } else if (IS_TEX(Desc)) {
108 int64_t Sampler = MI.getOperand(14).getImm();
109
110 int64_t SrcSelect[4] = {
111 MI.getOperand(2).getImm(), MI.getOperand(3).getImm(),
112 MI.getOperand(4).getImm(), MI.getOperand(5).getImm()};
113 int64_t Offsets[3] = {MI.getOperand(6).getImm() & 0x1F,
114 MI.getOperand(7).getImm() & 0x1F,
115 MI.getOperand(8).getImm() & 0x1F};
116
117 uint64_t Word01 = getBinaryCodeForInstr(MI, Fixups, STI);
118 uint32_t Word2 = Sampler << 15 | SrcSelect[ELEMENT_X] << 20 |
119 SrcSelect[ELEMENT_Y] << 23 | SrcSelect[ELEMENT_Z] << 26 |
120 SrcSelect[ELEMENT_W] << 29 | Offsets[0] << 0 |
121 Offsets[1] << 5 | Offsets[2] << 10;
122
123 emit(Word01, CB);
124 emit(Word2, CB);
125 emit((uint32_t)0, CB);
126 } else {
127 uint64_t Inst = getBinaryCodeForInstr(MI, Fixups, STI);
128 if ((STI.hasFeature(R600::FeatureR600ALUInst)) &&
129 ((Desc.TSFlags & R600_InstFlag::OP1) ||
130 Desc.TSFlags & R600_InstFlag::OP2)) {
131 uint64_t ISAOpCode = Inst & (0x3FFULL << 39);
132 Inst &= ~(0x3FFULL << 39);
133 Inst |= ISAOpCode << 1;
134 }
135 emit(Inst, CB);
136 }
137 }
138
emit(uint32_t Value,SmallVectorImpl<char> & CB) const139 void R600MCCodeEmitter::emit(uint32_t Value, SmallVectorImpl<char> &CB) const {
140 support::endian::write(CB, Value, llvm::endianness::little);
141 }
142
emit(uint64_t Value,SmallVectorImpl<char> & CB) const143 void R600MCCodeEmitter::emit(uint64_t Value, SmallVectorImpl<char> &CB) const {
144 support::endian::write(CB, Value, llvm::endianness::little);
145 }
146
getHWReg(MCRegister Reg) const147 unsigned R600MCCodeEmitter::getHWReg(MCRegister Reg) const {
148 return MRI.getEncodingValue(Reg) & HW_REG_MASK;
149 }
150
getMachineOpValue(const MCInst & MI,const MCOperand & MO,SmallVectorImpl<MCFixup> & Fixups,const MCSubtargetInfo & STI) const151 uint64_t R600MCCodeEmitter::getMachineOpValue(const MCInst &MI,
152 const MCOperand &MO,
153 SmallVectorImpl<MCFixup> &Fixups,
154 const MCSubtargetInfo &STI) const {
155 if (MO.isReg()) {
156 if (HAS_NATIVE_OPERANDS(MCII.get(MI.getOpcode()).TSFlags))
157 return MRI.getEncodingValue(MO.getReg());
158 return getHWReg(MO.getReg());
159 }
160
161 if (MO.isExpr()) {
162 // We put rodata at the end of code section, then map the entire
163 // code secetion as vtx buf. Thus the section relative address is the
164 // correct one.
165 // Each R600 literal instruction has two operands
166 // We can't easily get the order of the current one, so compare against
167 // the first one and adjust offset.
168 const unsigned offset = (&MO == &MI.getOperand(0)) ? 0 : 4;
169 Fixups.push_back(MCFixup::create(offset, MO.getExpr(), FK_SecRel_4));
170 return 0;
171 }
172
173 assert(MO.isImm());
174 return MO.getImm();
175 }
176
177 #include "R600GenMCCodeEmitter.inc"
178