xref: /freebsd/contrib/llvm-project/llvm/lib/ExecutionEngine/JITLink/aarch32.cpp (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
1 //===--------- aarch32.cpp - Generic JITLink arm/thumb utilities ----------===//
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 // Generic utilities for graphs representing arm/thumb objects.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/ExecutionEngine/JITLink/aarch32.h"
14 
15 #include "llvm/ADT/StringExtras.h"
16 #include "llvm/BinaryFormat/ELF.h"
17 #include "llvm/ExecutionEngine/JITLink/JITLink.h"
18 #include "llvm/Object/ELFObjectFile.h"
19 #include "llvm/Support/Endian.h"
20 #include "llvm/Support/MathExtras.h"
21 
22 #define DEBUG_TYPE "jitlink"
23 
24 namespace llvm {
25 namespace jitlink {
26 namespace aarch32 {
27 
28 /// Encode 22-bit immediate value for branch instructions without J1J2 range
29 /// extension (formats B T4, BL T1 and BLX T2).
30 ///
31 ///   00000:Imm11H:Imm11L:0 -> [ 00000:Imm11H, 00000:Imm11L ]
32 ///                                            J1^ ^J2 will always be 1
33 ///
34 HalfWords encodeImmBT4BlT1BlxT2(int64_t Value) {
35   constexpr uint32_t J1J2 = 0x2800;
36   uint32_t Imm11H = (Value >> 12) & 0x07ff;
37   uint32_t Imm11L = (Value >> 1) & 0x07ff;
38   return HalfWords{Imm11H, Imm11L | J1J2};
39 }
40 
41 /// Decode 22-bit immediate value for branch instructions without J1J2 range
42 /// extension (formats B T4, BL T1 and BLX T2).
43 ///
44 ///   [ 00000:Imm11H, 00000:Imm11L ] -> 00000:Imm11H:Imm11L:0
45 ///                   J1^ ^J2 will always be 1
46 ///
47 int64_t decodeImmBT4BlT1BlxT2(uint32_t Hi, uint32_t Lo) {
48   uint32_t Imm11H = Hi & 0x07ff;
49   uint32_t Imm11L = Lo & 0x07ff;
50   return SignExtend64<22>(Imm11H << 12 | Imm11L << 1);
51 }
52 
53 /// Encode 25-bit immediate value for branch instructions with J1J2 range
54 /// extension (formats B T4, BL T1 and BLX T2).
55 ///
56 ///   S:I1:I2:Imm10:Imm11:0 -> [ 00000:S:Imm10, 00:J1:0:J2:Imm11 ]
57 ///
58 HalfWords encodeImmBT4BlT1BlxT2_J1J2(int64_t Value) {
59   uint32_t S = (Value >> 14) & 0x0400;
60   uint32_t J1 = (((~(Value >> 10)) ^ (Value >> 11)) & 0x2000);
61   uint32_t J2 = (((~(Value >> 11)) ^ (Value >> 13)) & 0x0800);
62   uint32_t Imm10 = (Value >> 12) & 0x03ff;
63   uint32_t Imm11 = (Value >> 1) & 0x07ff;
64   return HalfWords{S | Imm10, J1 | J2 | Imm11};
65 }
66 
67 /// Decode 25-bit immediate value for branch instructions with J1J2 range
68 /// extension (formats B T4, BL T1 and BLX T2).
69 ///
70 ///   [ 00000:S:Imm10, 00:J1:0:J2:Imm11] -> S:I1:I2:Imm10:Imm11:0
71 ///
72 int64_t decodeImmBT4BlT1BlxT2_J1J2(uint32_t Hi, uint32_t Lo) {
73   uint32_t S = Hi & 0x0400;
74   uint32_t I1 = ~((Lo ^ (Hi << 3)) << 10) & 0x00800000;
75   uint32_t I2 = ~((Lo ^ (Hi << 1)) << 11) & 0x00400000;
76   uint32_t Imm10 = Hi & 0x03ff;
77   uint32_t Imm11 = Lo & 0x07ff;
78   return SignExtend64<25>(S << 14 | I1 | I2 | Imm10 << 12 | Imm11 << 1);
79 }
80 
81 /// Encode 16-bit immediate value for move instruction formats MOVT T1 and
82 /// MOVW T3.
83 ///
84 ///   Imm4:Imm1:Imm3:Imm8 -> [ 00000:i:000000:Imm4, 0:Imm3:0000:Imm8 ]
85 ///
86 HalfWords encodeImmMovtT1MovwT3(uint16_t Value) {
87   uint32_t Imm4 = (Value >> 12) & 0x0f;
88   uint32_t Imm1 = (Value >> 11) & 0x01;
89   uint32_t Imm3 = (Value >> 8) & 0x07;
90   uint32_t Imm8 = Value & 0xff;
91   return HalfWords{Imm1 << 10 | Imm4, Imm3 << 12 | Imm8};
92 }
93 
94 /// Decode 16-bit immediate value from move instruction formats MOVT T1 and
95 /// MOVW T3.
96 ///
97 ///   [ 00000:i:000000:Imm4, 0:Imm3:0000:Imm8 ] -> Imm4:Imm1:Imm3:Imm8
98 ///
99 uint16_t decodeImmMovtT1MovwT3(uint32_t Hi, uint32_t Lo) {
100   uint32_t Imm4 = Hi & 0x0f;
101   uint32_t Imm1 = (Hi >> 10) & 0x01;
102   uint32_t Imm3 = (Lo >> 12) & 0x07;
103   uint32_t Imm8 = Lo & 0xff;
104   uint32_t Imm16 = Imm4 << 12 | Imm1 << 11 | Imm3 << 8 | Imm8;
105   assert(Imm16 <= 0xffff && "Decoded value out-of-range");
106   return Imm16;
107 }
108 
109 /// Encode register ID for instruction formats MOVT T1 and MOVW T3.
110 ///
111 ///   Rd4 -> [0000000000000000, 0000:Rd4:00000000]
112 ///
113 HalfWords encodeRegMovtT1MovwT3(int64_t Value) {
114   uint32_t Rd4 = (Value & 0x0f) << 8;
115   return HalfWords{0, Rd4};
116 }
117 
118 /// Decode register ID from instruction formats MOVT T1 and MOVW T3.
119 ///
120 ///   [0000000000000000, 0000:Rd4:00000000] -> Rd4
121 ///
122 int64_t decodeRegMovtT1MovwT3(uint32_t Hi, uint32_t Lo) {
123   uint32_t Rd4 = (Lo >> 8) & 0x0f;
124   return Rd4;
125 }
126 
127 /// 32-bit Thumb instructions are stored as two little-endian halfwords.
128 /// An instruction at address A encodes bytes A+1, A in the first halfword (Hi),
129 /// followed by bytes A+3, A+2 in the second halfword (Lo).
130 struct WritableThumbRelocation {
131   /// Create a writable reference to a Thumb32 fixup.
132   WritableThumbRelocation(char *FixupPtr)
133       : Hi{*reinterpret_cast<support::ulittle16_t *>(FixupPtr)},
134         Lo{*reinterpret_cast<support::ulittle16_t *>(FixupPtr + 2)} {}
135 
136   support::ulittle16_t &Hi; // First halfword
137   support::ulittle16_t &Lo; // Second halfword
138 };
139 
140 struct ThumbRelocation {
141   /// Create a read-only reference to a Thumb32 fixup.
142   ThumbRelocation(const char *FixupPtr)
143       : Hi{*reinterpret_cast<const support::ulittle16_t *>(FixupPtr)},
144         Lo{*reinterpret_cast<const support::ulittle16_t *>(FixupPtr + 2)} {}
145 
146   /// Create a read-only Thumb32 fixup from a writeable one.
147   ThumbRelocation(WritableThumbRelocation &Writable)
148       : Hi{Writable.Hi}, Lo(Writable.Lo) {}
149 
150   const support::ulittle16_t &Hi; // First halfword
151   const support::ulittle16_t &Lo; // Second halfword
152 };
153 
154 Error makeUnexpectedOpcodeError(const LinkGraph &G, const ThumbRelocation &R,
155                                 Edge::Kind Kind) {
156   return make_error<JITLinkError>(
157       formatv("Invalid opcode [ 0x{0:x4}, 0x{1:x4} ] for relocation: {2}",
158               static_cast<uint16_t>(R.Hi), static_cast<uint16_t>(R.Lo),
159               G.getEdgeKindName(Kind)));
160 }
161 
162 template <EdgeKind_aarch32 Kind> bool checkOpcode(const ThumbRelocation &R) {
163   uint16_t Hi = R.Hi & FixupInfo<Kind>::OpcodeMask.Hi;
164   uint16_t Lo = R.Lo & FixupInfo<Kind>::OpcodeMask.Lo;
165   return Hi == FixupInfo<Kind>::Opcode.Hi && Lo == FixupInfo<Kind>::Opcode.Lo;
166 }
167 
168 template <EdgeKind_aarch32 Kind>
169 bool checkRegister(const ThumbRelocation &R, HalfWords Reg) {
170   uint16_t Hi = R.Hi & FixupInfo<Kind>::RegMask.Hi;
171   uint16_t Lo = R.Lo & FixupInfo<Kind>::RegMask.Lo;
172   return Hi == Reg.Hi && Lo == Reg.Lo;
173 }
174 
175 template <EdgeKind_aarch32 Kind>
176 void writeRegister(WritableThumbRelocation &R, HalfWords Reg) {
177   static constexpr HalfWords Mask = FixupInfo<Kind>::RegMask;
178   assert((Mask.Hi & Reg.Hi) == Reg.Hi && (Mask.Hi & Reg.Hi) == Reg.Hi &&
179          "Value bits exceed bit range of given mask");
180   R.Hi = (R.Hi & ~Mask.Hi) | Reg.Hi;
181   R.Lo = (R.Lo & ~Mask.Lo) | Reg.Lo;
182 }
183 
184 template <EdgeKind_aarch32 Kind>
185 void writeImmediate(WritableThumbRelocation &R, HalfWords Imm) {
186   static constexpr HalfWords Mask = FixupInfo<Kind>::ImmMask;
187   assert((Mask.Hi & Imm.Hi) == Imm.Hi && (Mask.Hi & Imm.Hi) == Imm.Hi &&
188          "Value bits exceed bit range of given mask");
189   R.Hi = (R.Hi & ~Mask.Hi) | Imm.Hi;
190   R.Lo = (R.Lo & ~Mask.Lo) | Imm.Lo;
191 }
192 
193 Expected<int64_t> readAddendData(LinkGraph &G, Block &B, const Edge &E) {
194   support::endianness Endian = G.getEndianness();
195   assert(Endian != support::native && "Declare as little or big explicitly");
196 
197   Edge::Kind Kind = E.getKind();
198   const char *BlockWorkingMem = B.getContent().data();
199   const char *FixupPtr = BlockWorkingMem + E.getOffset();
200 
201   switch (Kind) {
202   case Data_Delta32:
203   case Data_Pointer32:
204     return SignExtend64<32>(support::endian::read32(FixupPtr, Endian));
205   default:
206     return make_error<JITLinkError>(
207         "In graph " + G.getName() + ", section " + B.getSection().getName() +
208         " can not read implicit addend for aarch32 edge kind " +
209         G.getEdgeKindName(E.getKind()));
210   }
211 }
212 
213 Expected<int64_t> readAddendArm(LinkGraph &G, Block &B, const Edge &E) {
214   Edge::Kind Kind = E.getKind();
215 
216   switch (Kind) {
217   case Arm_Call:
218     return make_error<JITLinkError>(
219         "Addend extraction for relocation type not yet implemented: " +
220         StringRef(G.getEdgeKindName(Kind)));
221   default:
222     return make_error<JITLinkError>(
223         "In graph " + G.getName() + ", section " + B.getSection().getName() +
224         " can not read implicit addend for aarch32 edge kind " +
225         G.getEdgeKindName(E.getKind()));
226   }
227 }
228 
229 Expected<int64_t> readAddendThumb(LinkGraph &G, Block &B, const Edge &E,
230                                   const ArmConfig &ArmCfg) {
231   ThumbRelocation R(B.getContent().data() + E.getOffset());
232   Edge::Kind Kind = E.getKind();
233 
234   switch (Kind) {
235   case Thumb_Call:
236     if (!checkOpcode<Thumb_Call>(R))
237       return makeUnexpectedOpcodeError(G, R, Kind);
238     return LLVM_LIKELY(ArmCfg.J1J2BranchEncoding)
239                ? decodeImmBT4BlT1BlxT2_J1J2(R.Hi, R.Lo)
240                : decodeImmBT4BlT1BlxT2(R.Hi, R.Lo);
241 
242   case Thumb_Jump24:
243     if (!checkOpcode<Thumb_Jump24>(R))
244       return makeUnexpectedOpcodeError(G, R, Kind);
245     if (R.Lo & FixupInfo<Thumb_Jump24>::LoBitConditional)
246       return make_error<JITLinkError>("Relocation expects an unconditional "
247                                       "B.W branch instruction: " +
248                                       StringRef(G.getEdgeKindName(Kind)));
249     return LLVM_LIKELY(ArmCfg.J1J2BranchEncoding)
250                   ? decodeImmBT4BlT1BlxT2_J1J2(R.Hi, R.Lo)
251                   : decodeImmBT4BlT1BlxT2(R.Hi, R.Lo);
252 
253   case Thumb_MovwAbsNC:
254     if (!checkOpcode<Thumb_MovwAbsNC>(R))
255       return makeUnexpectedOpcodeError(G, R, Kind);
256     // Initial addend is interpreted as a signed value
257     return SignExtend64<16>(decodeImmMovtT1MovwT3(R.Hi, R.Lo));
258 
259   case Thumb_MovtAbs:
260     if (!checkOpcode<Thumb_MovtAbs>(R))
261       return makeUnexpectedOpcodeError(G, R, Kind);
262     // Initial addend is interpreted as a signed value
263     return SignExtend64<16>(decodeImmMovtT1MovwT3(R.Hi, R.Lo));
264 
265   default:
266     return make_error<JITLinkError>(
267         "In graph " + G.getName() + ", section " + B.getSection().getName() +
268         " can not read implicit addend for aarch32 edge kind " +
269         G.getEdgeKindName(E.getKind()));
270   }
271 }
272 
273 Error applyFixupData(LinkGraph &G, Block &B, const Edge &E) {
274   using namespace support;
275 
276   char *BlockWorkingMem = B.getAlreadyMutableContent().data();
277   char *FixupPtr = BlockWorkingMem + E.getOffset();
278 
279   auto Write32 = [FixupPtr, Endian = G.getEndianness()](int64_t Value) {
280     assert(Endian != native && "Must be explicit: little or big");
281     assert(isInt<32>(Value) && "Must be in signed 32-bit range");
282     uint32_t Imm = static_cast<int32_t>(Value);
283     if (LLVM_LIKELY(Endian == little))
284       endian::write32<little>(FixupPtr, Imm);
285     else
286       endian::write32<big>(FixupPtr, Imm);
287   };
288 
289   Edge::Kind Kind = E.getKind();
290   uint64_t FixupAddress = (B.getAddress() + E.getOffset()).getValue();
291   int64_t Addend = E.getAddend();
292   Symbol &TargetSymbol = E.getTarget();
293   uint64_t TargetAddress = TargetSymbol.getAddress().getValue();
294   assert(!TargetSymbol.hasTargetFlags(ThumbSymbol));
295 
296   // Regular data relocations have size 4, alignment 1 and write the full 32-bit
297   // result to the place; no need for overflow checking. There are three
298   // exceptions: R_ARM_ABS8, R_ARM_ABS16, R_ARM_PREL31
299   switch (Kind) {
300   case Data_Delta32: {
301     int64_t Value = TargetAddress - FixupAddress + Addend;
302     if (!isInt<32>(Value))
303       return makeTargetOutOfRangeError(G, B, E);
304     Write32(Value);
305     return Error::success();
306   }
307   case Data_Pointer32: {
308     int64_t Value = TargetAddress + Addend;
309     if (!isInt<32>(Value))
310       return makeTargetOutOfRangeError(G, B, E);
311     Write32(Value);
312     return Error::success();
313   }
314   default:
315     return make_error<JITLinkError>(
316         "In graph " + G.getName() + ", section " + B.getSection().getName() +
317         " encountered unfixable aarch32 edge kind " +
318         G.getEdgeKindName(E.getKind()));
319   }
320 }
321 
322 Error applyFixupArm(LinkGraph &G, Block &B, const Edge &E) {
323   Edge::Kind Kind = E.getKind();
324 
325   switch (Kind) {
326   case Arm_Call:
327     return make_error<JITLinkError>(
328         "Fix-up for relocation type not yet implemented: " +
329         StringRef(G.getEdgeKindName(Kind)));
330   default:
331     return make_error<JITLinkError>(
332         "In graph " + G.getName() + ", section " + B.getSection().getName() +
333         " encountered unfixable aarch32 edge kind " +
334         G.getEdgeKindName(E.getKind()));
335   }
336 }
337 
338 Error applyFixupThumb(LinkGraph &G, Block &B, const Edge &E,
339                       const ArmConfig &ArmCfg) {
340   WritableThumbRelocation R(B.getAlreadyMutableContent().data() +
341                             E.getOffset());
342 
343   Edge::Kind Kind = E.getKind();
344   uint64_t FixupAddress = (B.getAddress() + E.getOffset()).getValue();
345   int64_t Addend = E.getAddend();
346   Symbol &TargetSymbol = E.getTarget();
347   uint64_t TargetAddress = TargetSymbol.getAddress().getValue();
348   if (TargetSymbol.hasTargetFlags(ThumbSymbol))
349     TargetAddress |= 0x01;
350 
351   switch (Kind) {
352   case Thumb_Jump24: {
353     if (!checkOpcode<Thumb_Jump24>(R))
354       return makeUnexpectedOpcodeError(G, R, Kind);
355     if (R.Lo & FixupInfo<Thumb_Jump24>::LoBitConditional)
356       return make_error<JITLinkError>("Relocation expects an unconditional "
357                                       "B.W branch instruction: " +
358                                       StringRef(G.getEdgeKindName(Kind)));
359     if (!(TargetSymbol.hasTargetFlags(ThumbSymbol)))
360       return make_error<JITLinkError>("Branch relocation needs interworking "
361                                       "stub when bridging to ARM: " +
362                                       StringRef(G.getEdgeKindName(Kind)));
363 
364     int64_t Value = TargetAddress - FixupAddress + Addend;
365     if (LLVM_LIKELY(ArmCfg.J1J2BranchEncoding)) {
366       if (!isInt<25>(Value))
367         return makeTargetOutOfRangeError(G, B, E);
368       writeImmediate<Thumb_Jump24>(R, encodeImmBT4BlT1BlxT2_J1J2(Value));
369     } else {
370       if (!isInt<22>(Value))
371         return makeTargetOutOfRangeError(G, B, E);
372       writeImmediate<Thumb_Jump24>(R, encodeImmBT4BlT1BlxT2(Value));
373     }
374 
375     return Error::success();
376   }
377 
378   case Thumb_Call: {
379     if (!checkOpcode<Thumb_Call>(R))
380       return makeUnexpectedOpcodeError(G, R, Kind);
381 
382     int64_t Value = TargetAddress - FixupAddress + Addend;
383 
384     // The call instruction itself is Thumb. The call destination can either be
385     // Thumb or Arm. We use BL to stay in Thumb and BLX to change to Arm.
386     bool TargetIsArm = !TargetSymbol.hasTargetFlags(ThumbSymbol);
387     bool InstrIsBlx = (R.Lo & FixupInfo<Thumb_Call>::LoBitNoBlx) == 0;
388     if (TargetIsArm != InstrIsBlx) {
389       if (LLVM_LIKELY(TargetIsArm)) {
390         // Change opcode BL -> BLX and fix range value (account for 4-byte
391         // aligned destination while instruction may only be 2-byte aligned
392         // and clear Thumb bit).
393         R.Lo = R.Lo & ~FixupInfo<Thumb_Call>::LoBitNoBlx;
394         R.Lo = R.Lo & ~FixupInfo<Thumb_Call>::LoBitH;
395         Value = alignTo(Value, 4);
396       } else {
397         // Change opcode BLX -> BL and set Thumb bit
398         R.Lo = R.Lo & ~FixupInfo<Thumb_Call>::LoBitNoBlx;
399         Value |= 0x01;
400       }
401     }
402 
403     if (LLVM_LIKELY(ArmCfg.J1J2BranchEncoding)) {
404       if (!isInt<25>(Value))
405         return makeTargetOutOfRangeError(G, B, E);
406       writeImmediate<Thumb_Call>(R, encodeImmBT4BlT1BlxT2_J1J2(Value));
407     } else {
408       if (!isInt<22>(Value))
409         return makeTargetOutOfRangeError(G, B, E);
410       writeImmediate<Thumb_Call>(R, encodeImmBT4BlT1BlxT2(Value));
411     }
412 
413     assert(((R.Lo & FixupInfo<Thumb_Call>::LoBitNoBlx) ||
414             (R.Lo & FixupInfo<Thumb_Call>::LoBitH) == 0) &&
415            "Opcode BLX implies H bit is clear (avoid UB in BLX T2)");
416     return Error::success();
417   }
418 
419   case Thumb_MovwAbsNC: {
420     if (!checkOpcode<Thumb_MovwAbsNC>(R))
421       return makeUnexpectedOpcodeError(G, R, Kind);
422     uint16_t Value = (TargetAddress + Addend) & 0xffff;
423     writeImmediate<Thumb_MovwAbsNC>(R, encodeImmMovtT1MovwT3(Value));
424     return Error::success();
425   }
426 
427   case Thumb_MovtAbs: {
428     if (!checkOpcode<Thumb_MovtAbs>(R))
429       return makeUnexpectedOpcodeError(G, R, Kind);
430     uint16_t Value = ((TargetAddress + Addend) >> 16) & 0xffff;
431     writeImmediate<Thumb_MovtAbs>(R, encodeImmMovtT1MovwT3(Value));
432     return Error::success();
433   }
434 
435   default:
436     return make_error<JITLinkError>(
437         "In graph " + G.getName() + ", section " + B.getSection().getName() +
438         " encountered unfixable aarch32 edge kind " +
439         G.getEdgeKindName(E.getKind()));
440   }
441 }
442 
443 const uint8_t Thumbv7ABS[] = {
444     0x40, 0xf2, 0x00, 0x0c, // movw r12, #0x0000    ; lower 16-bit
445     0xc0, 0xf2, 0x00, 0x0c, // movt r12, #0x0000    ; upper 16-bit
446     0x60, 0x47              // bx   r12
447 };
448 
449 template <>
450 Symbol &StubsManager<Thumbv7>::createEntry(LinkGraph &G, Symbol &Target) {
451   constexpr uint64_t Alignment = 4;
452   Block &B = addStub(G, Thumbv7ABS, Alignment);
453   LLVM_DEBUG({
454     const char *StubPtr = B.getContent().data();
455     HalfWords Reg12 = encodeRegMovtT1MovwT3(12);
456     assert(checkRegister<Thumb_MovwAbsNC>(StubPtr, Reg12) &&
457            checkRegister<Thumb_MovtAbs>(StubPtr + 4, Reg12) &&
458            "Linker generated stubs may only corrupt register r12 (IP)");
459   });
460   B.addEdge(Thumb_MovwAbsNC, 0, Target, 0);
461   B.addEdge(Thumb_MovtAbs, 4, Target, 0);
462   Symbol &Stub = G.addAnonymousSymbol(B, 0, B.getSize(), true, false);
463   Stub.setTargetFlags(ThumbSymbol);
464   return Stub;
465 }
466 
467 const char *getEdgeKindName(Edge::Kind K) {
468 #define KIND_NAME_CASE(K)                                                      \
469   case K:                                                                      \
470     return #K;
471 
472   switch (K) {
473     KIND_NAME_CASE(Data_Delta32)
474     KIND_NAME_CASE(Arm_Call)
475     KIND_NAME_CASE(Thumb_Call)
476     KIND_NAME_CASE(Thumb_Jump24)
477     KIND_NAME_CASE(Thumb_MovwAbsNC)
478     KIND_NAME_CASE(Thumb_MovtAbs)
479   default:
480     return getGenericEdgeKindName(K);
481   }
482 #undef KIND_NAME_CASE
483 }
484 
485 const char *getCPUArchName(ARMBuildAttrs::CPUArch K) {
486 #define CPUARCH_NAME_CASE(K)                                                   \
487   case K:                                                                      \
488     return #K;
489 
490   using namespace ARMBuildAttrs;
491   switch (K) {
492     CPUARCH_NAME_CASE(Pre_v4)
493     CPUARCH_NAME_CASE(v4)
494     CPUARCH_NAME_CASE(v4T)
495     CPUARCH_NAME_CASE(v5T)
496     CPUARCH_NAME_CASE(v5TE)
497     CPUARCH_NAME_CASE(v5TEJ)
498     CPUARCH_NAME_CASE(v6)
499     CPUARCH_NAME_CASE(v6KZ)
500     CPUARCH_NAME_CASE(v6T2)
501     CPUARCH_NAME_CASE(v6K)
502     CPUARCH_NAME_CASE(v7)
503     CPUARCH_NAME_CASE(v6_M)
504     CPUARCH_NAME_CASE(v6S_M)
505     CPUARCH_NAME_CASE(v7E_M)
506     CPUARCH_NAME_CASE(v8_A)
507     CPUARCH_NAME_CASE(v8_R)
508     CPUARCH_NAME_CASE(v8_M_Base)
509     CPUARCH_NAME_CASE(v8_M_Main)
510     CPUARCH_NAME_CASE(v8_1_M_Main)
511     CPUARCH_NAME_CASE(v9_A)
512   }
513   llvm_unreachable("Missing CPUArch in switch?");
514 #undef CPUARCH_NAME_CASE
515 }
516 
517 } // namespace aarch32
518 } // namespace jitlink
519 } // namespace llvm
520