1 //===-- ARMTargetParser - Parser for ARM target features --------*- C++ -*-===//
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 // This file implements a target parser to recognise ARM hardware features
10 // such as FPU/CPU/ARCH/extensions and specific support such as HWDIV.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Support/ARMTargetParser.h"
15 #include "llvm/ADT/StringSwitch.h"
16 #include <cctype>
17 
18 using namespace llvm;
19 
20 static StringRef getHWDivSynonym(StringRef HWDiv) {
21   return StringSwitch<StringRef>(HWDiv)
22       .Case("thumb,arm", "arm,thumb")
23       .Default(HWDiv);
24 }
25 
26 // Allows partial match, ex. "v7a" matches "armv7a".
27 ARM::ArchKind ARM::parseArch(StringRef Arch) {
28   Arch = getCanonicalArchName(Arch);
29   StringRef Syn = getArchSynonym(Arch);
30   for (const auto &A : ARCHNames) {
31     if (A.getName().endswith(Syn))
32       return A.ID;
33   }
34   return ArchKind::INVALID;
35 }
36 
37 // Version number (ex. v7 = 7).
38 unsigned ARM::parseArchVersion(StringRef Arch) {
39   Arch = getCanonicalArchName(Arch);
40   switch (parseArch(Arch)) {
41   case ArchKind::ARMV2:
42   case ArchKind::ARMV2A:
43     return 2;
44   case ArchKind::ARMV3:
45   case ArchKind::ARMV3M:
46     return 3;
47   case ArchKind::ARMV4:
48   case ArchKind::ARMV4T:
49     return 4;
50   case ArchKind::ARMV5T:
51   case ArchKind::ARMV5TE:
52   case ArchKind::IWMMXT:
53   case ArchKind::IWMMXT2:
54   case ArchKind::XSCALE:
55   case ArchKind::ARMV5TEJ:
56     return 5;
57   case ArchKind::ARMV6:
58   case ArchKind::ARMV6K:
59   case ArchKind::ARMV6T2:
60   case ArchKind::ARMV6KZ:
61   case ArchKind::ARMV6M:
62     return 6;
63   case ArchKind::ARMV7A:
64   case ArchKind::ARMV7VE:
65   case ArchKind::ARMV7R:
66   case ArchKind::ARMV7M:
67   case ArchKind::ARMV7S:
68   case ArchKind::ARMV7EM:
69   case ArchKind::ARMV7K:
70     return 7;
71   case ArchKind::ARMV8A:
72   case ArchKind::ARMV8_1A:
73   case ArchKind::ARMV8_2A:
74   case ArchKind::ARMV8_3A:
75   case ArchKind::ARMV8_4A:
76   case ArchKind::ARMV8_5A:
77   case ArchKind::ARMV8R:
78   case ArchKind::ARMV8MBaseline:
79   case ArchKind::ARMV8MMainline:
80   case ArchKind::ARMV8_1MMainline:
81     return 8;
82   case ArchKind::INVALID:
83     return 0;
84   }
85   llvm_unreachable("Unhandled architecture");
86 }
87 
88 // Profile A/R/M
89 ARM::ProfileKind ARM::parseArchProfile(StringRef Arch) {
90   Arch = getCanonicalArchName(Arch);
91   switch (parseArch(Arch)) {
92   case ArchKind::ARMV6M:
93   case ArchKind::ARMV7M:
94   case ArchKind::ARMV7EM:
95   case ArchKind::ARMV8MMainline:
96   case ArchKind::ARMV8MBaseline:
97   case ArchKind::ARMV8_1MMainline:
98     return ProfileKind::M;
99   case ArchKind::ARMV7R:
100   case ArchKind::ARMV8R:
101     return ProfileKind::R;
102   case ArchKind::ARMV7A:
103   case ArchKind::ARMV7VE:
104   case ArchKind::ARMV7K:
105   case ArchKind::ARMV8A:
106   case ArchKind::ARMV8_1A:
107   case ArchKind::ARMV8_2A:
108   case ArchKind::ARMV8_3A:
109   case ArchKind::ARMV8_4A:
110   case ArchKind::ARMV8_5A:
111     return ProfileKind::A;
112   case ArchKind::ARMV2:
113   case ArchKind::ARMV2A:
114   case ArchKind::ARMV3:
115   case ArchKind::ARMV3M:
116   case ArchKind::ARMV4:
117   case ArchKind::ARMV4T:
118   case ArchKind::ARMV5T:
119   case ArchKind::ARMV5TE:
120   case ArchKind::ARMV5TEJ:
121   case ArchKind::ARMV6:
122   case ArchKind::ARMV6K:
123   case ArchKind::ARMV6T2:
124   case ArchKind::ARMV6KZ:
125   case ArchKind::ARMV7S:
126   case ArchKind::IWMMXT:
127   case ArchKind::IWMMXT2:
128   case ArchKind::XSCALE:
129   case ArchKind::INVALID:
130     return ProfileKind::INVALID;
131   }
132   llvm_unreachable("Unhandled architecture");
133 }
134 
135 StringRef ARM::getArchSynonym(StringRef Arch) {
136   return StringSwitch<StringRef>(Arch)
137       .Case("v5", "v5t")
138       .Case("v5e", "v5te")
139       .Case("v6j", "v6")
140       .Case("v6hl", "v6k")
141       .Cases("v6m", "v6sm", "v6s-m", "v6-m")
142       .Cases("v6z", "v6zk", "v6kz")
143       .Cases("v7", "v7a", "v7hl", "v7l", "v7-a")
144       .Case("v7r", "v7-r")
145       .Case("v7m", "v7-m")
146       .Case("v7em", "v7e-m")
147       .Cases("v8", "v8a", "v8l", "aarch64", "arm64", "v8-a")
148       .Case("v8.1a", "v8.1-a")
149       .Case("v8.2a", "v8.2-a")
150       .Case("v8.3a", "v8.3-a")
151       .Case("v8.4a", "v8.4-a")
152       .Case("v8.5a", "v8.5-a")
153       .Case("v8r", "v8-r")
154       .Case("v8m.base", "v8-m.base")
155       .Case("v8m.main", "v8-m.main")
156       .Case("v8.1m.main", "v8.1-m.main")
157       .Default(Arch);
158 }
159 
160 bool ARM::getFPUFeatures(unsigned FPUKind, std::vector<StringRef> &Features) {
161 
162   if (FPUKind >= FK_LAST || FPUKind == FK_INVALID)
163     return false;
164 
165   static const struct FPUFeatureNameInfo {
166     const char *PlusName, *MinusName;
167     FPUVersion MinVersion;
168     FPURestriction MaxRestriction;
169   } FPUFeatureInfoList[] = {
170     // We have to specify the + and - versions of the name in full so
171     // that we can return them as static StringRefs.
172     //
173     // Also, the SubtargetFeatures ending in just "sp" are listed here
174     // under FPURestriction::None, which is the only FPURestriction in
175     // which they would be valid (since FPURestriction::SP doesn't
176     // exist).
177     {"+vfp2", "-vfp2", FPUVersion::VFPV2, FPURestriction::D16},
178     {"+vfp2sp", "-vfp2sp", FPUVersion::VFPV2, FPURestriction::SP_D16},
179     {"+vfp3", "-vfp3", FPUVersion::VFPV3, FPURestriction::None},
180     {"+vfp3d16", "-vfp3d16", FPUVersion::VFPV3, FPURestriction::D16},
181     {"+vfp3d16sp", "-vfp3d16sp", FPUVersion::VFPV3, FPURestriction::SP_D16},
182     {"+vfp3sp", "-vfp3sp", FPUVersion::VFPV3, FPURestriction::None},
183     {"+fp16", "-fp16", FPUVersion::VFPV3_FP16, FPURestriction::SP_D16},
184     {"+vfp4", "-vfp4", FPUVersion::VFPV4, FPURestriction::None},
185     {"+vfp4d16", "-vfp4d16", FPUVersion::VFPV4, FPURestriction::D16},
186     {"+vfp4d16sp", "-vfp4d16sp", FPUVersion::VFPV4, FPURestriction::SP_D16},
187     {"+vfp4sp", "-vfp4sp", FPUVersion::VFPV4, FPURestriction::None},
188     {"+fp-armv8", "-fp-armv8", FPUVersion::VFPV5, FPURestriction::None},
189     {"+fp-armv8d16", "-fp-armv8d16", FPUVersion::VFPV5, FPURestriction::D16},
190     {"+fp-armv8d16sp", "-fp-armv8d16sp", FPUVersion::VFPV5, FPURestriction::SP_D16},
191     {"+fp-armv8sp", "-fp-armv8sp", FPUVersion::VFPV5, FPURestriction::None},
192     {"+fullfp16", "-fullfp16", FPUVersion::VFPV5_FULLFP16, FPURestriction::SP_D16},
193     {"+fp64", "-fp64", FPUVersion::VFPV2, FPURestriction::D16},
194     {"+d32", "-d32", FPUVersion::VFPV3, FPURestriction::None},
195   };
196 
197   for (const auto &Info: FPUFeatureInfoList) {
198     if (FPUNames[FPUKind].FPUVer >= Info.MinVersion &&
199         FPUNames[FPUKind].Restriction <= Info.MaxRestriction)
200       Features.push_back(Info.PlusName);
201     else
202       Features.push_back(Info.MinusName);
203   }
204 
205   static const struct NeonFeatureNameInfo {
206     const char *PlusName, *MinusName;
207     NeonSupportLevel MinSupportLevel;
208   } NeonFeatureInfoList[] = {
209     {"+neon", "-neon", NeonSupportLevel::Neon},
210     {"+crypto", "-crypto", NeonSupportLevel::Crypto},
211   };
212 
213   for (const auto &Info: NeonFeatureInfoList) {
214     if (FPUNames[FPUKind].NeonSupport >= Info.MinSupportLevel)
215       Features.push_back(Info.PlusName);
216     else
217       Features.push_back(Info.MinusName);
218   }
219 
220   return true;
221 }
222 
223 // Little/Big endian
224 ARM::EndianKind ARM::parseArchEndian(StringRef Arch) {
225   if (Arch.startswith("armeb") || Arch.startswith("thumbeb") ||
226       Arch.startswith("aarch64_be"))
227     return EndianKind::BIG;
228 
229   if (Arch.startswith("arm") || Arch.startswith("thumb")) {
230     if (Arch.endswith("eb"))
231       return EndianKind::BIG;
232     else
233       return EndianKind::LITTLE;
234   }
235 
236   if (Arch.startswith("aarch64") || Arch.startswith("aarch64_32"))
237     return EndianKind::LITTLE;
238 
239   return EndianKind::INVALID;
240 }
241 
242 // ARM, Thumb, AArch64
243 ARM::ISAKind ARM::parseArchISA(StringRef Arch) {
244   return StringSwitch<ISAKind>(Arch)
245       .StartsWith("aarch64", ISAKind::AARCH64)
246       .StartsWith("arm64", ISAKind::AARCH64)
247       .StartsWith("thumb", ISAKind::THUMB)
248       .StartsWith("arm", ISAKind::ARM)
249       .Default(ISAKind::INVALID);
250 }
251 
252 unsigned ARM::parseFPU(StringRef FPU) {
253   StringRef Syn = getFPUSynonym(FPU);
254   for (const auto F : FPUNames) {
255     if (Syn == F.getName())
256       return F.ID;
257   }
258   return FK_INVALID;
259 }
260 
261 ARM::NeonSupportLevel ARM::getFPUNeonSupportLevel(unsigned FPUKind) {
262   if (FPUKind >= FK_LAST)
263     return NeonSupportLevel::None;
264   return FPUNames[FPUKind].NeonSupport;
265 }
266 
267 // MArch is expected to be of the form (arm|thumb)?(eb)?(v.+)?(eb)?, but
268 // (iwmmxt|xscale)(eb)? is also permitted. If the former, return
269 // "v.+", if the latter, return unmodified string, minus 'eb'.
270 // If invalid, return empty string.
271 StringRef ARM::getCanonicalArchName(StringRef Arch) {
272   size_t offset = StringRef::npos;
273   StringRef A = Arch;
274   StringRef Error = "";
275 
276   // Begins with "arm" / "thumb", move past it.
277   if (A.startswith("arm64_32"))
278     offset = 8;
279   else if (A.startswith("arm64"))
280     offset = 5;
281   else if (A.startswith("aarch64_32"))
282     offset = 10;
283   else if (A.startswith("arm"))
284     offset = 3;
285   else if (A.startswith("thumb"))
286     offset = 5;
287   else if (A.startswith("aarch64")) {
288     offset = 7;
289     // AArch64 uses "_be", not "eb" suffix.
290     if (A.find("eb") != StringRef::npos)
291       return Error;
292     if (A.substr(offset, 3) == "_be")
293       offset += 3;
294   }
295 
296   // Ex. "armebv7", move past the "eb".
297   if (offset != StringRef::npos && A.substr(offset, 2) == "eb")
298     offset += 2;
299   // Or, if it ends with eb ("armv7eb"), chop it off.
300   else if (A.endswith("eb"))
301     A = A.substr(0, A.size() - 2);
302   // Trim the head
303   if (offset != StringRef::npos)
304     A = A.substr(offset);
305 
306   // Empty string means offset reached the end, which means it's valid.
307   if (A.empty())
308     return Arch;
309 
310   // Only match non-marketing names
311   if (offset != StringRef::npos) {
312     // Must start with 'vN'.
313     if (A.size() >= 2 && (A[0] != 'v' || !std::isdigit(A[1])))
314       return Error;
315     // Can't have an extra 'eb'.
316     if (A.find("eb") != StringRef::npos)
317       return Error;
318   }
319 
320   // Arch will either be a 'v' name (v7a) or a marketing name (xscale).
321   return A;
322 }
323 
324 StringRef ARM::getFPUSynonym(StringRef FPU) {
325   return StringSwitch<StringRef>(FPU)
326       .Cases("fpa", "fpe2", "fpe3", "maverick", "invalid") // Unsupported
327       .Case("vfp2", "vfpv2")
328       .Case("vfp3", "vfpv3")
329       .Case("vfp4", "vfpv4")
330       .Case("vfp3-d16", "vfpv3-d16")
331       .Case("vfp4-d16", "vfpv4-d16")
332       .Cases("fp4-sp-d16", "vfpv4-sp-d16", "fpv4-sp-d16")
333       .Cases("fp4-dp-d16", "fpv4-dp-d16", "vfpv4-d16")
334       .Case("fp5-sp-d16", "fpv5-sp-d16")
335       .Cases("fp5-dp-d16", "fpv5-dp-d16", "fpv5-d16")
336       // FIXME: Clang uses it, but it's bogus, since neon defaults to vfpv3.
337       .Case("neon-vfpv3", "neon")
338       .Default(FPU);
339 }
340 
341 StringRef ARM::getFPUName(unsigned FPUKind) {
342   if (FPUKind >= FK_LAST)
343     return StringRef();
344   return FPUNames[FPUKind].getName();
345 }
346 
347 ARM::FPUVersion ARM::getFPUVersion(unsigned FPUKind) {
348   if (FPUKind >= FK_LAST)
349     return FPUVersion::NONE;
350   return FPUNames[FPUKind].FPUVer;
351 }
352 
353 ARM::FPURestriction ARM::getFPURestriction(unsigned FPUKind) {
354   if (FPUKind >= FK_LAST)
355     return FPURestriction::None;
356   return FPUNames[FPUKind].Restriction;
357 }
358 
359 unsigned ARM::getDefaultFPU(StringRef CPU, ARM::ArchKind AK) {
360   if (CPU == "generic")
361     return ARM::ARCHNames[static_cast<unsigned>(AK)].DefaultFPU;
362 
363   return StringSwitch<unsigned>(CPU)
364 #define ARM_CPU_NAME(NAME, ID, DEFAULT_FPU, IS_DEFAULT, DEFAULT_EXT)           \
365   .Case(NAME, DEFAULT_FPU)
366 #include "llvm/Support/ARMTargetParser.def"
367    .Default(ARM::FK_INVALID);
368 }
369 
370 uint64_t ARM::getDefaultExtensions(StringRef CPU, ARM::ArchKind AK) {
371   if (CPU == "generic")
372     return ARM::ARCHNames[static_cast<unsigned>(AK)].ArchBaseExtensions;
373 
374   return StringSwitch<uint64_t>(CPU)
375 #define ARM_CPU_NAME(NAME, ID, DEFAULT_FPU, IS_DEFAULT, DEFAULT_EXT)           \
376   .Case(NAME,                                                                  \
377         ARCHNames[static_cast<unsigned>(ArchKind::ID)].ArchBaseExtensions |    \
378             DEFAULT_EXT)
379 #include "llvm/Support/ARMTargetParser.def"
380   .Default(ARM::AEK_INVALID);
381 }
382 
383 bool ARM::getHWDivFeatures(uint64_t HWDivKind,
384                            std::vector<StringRef> &Features) {
385 
386   if (HWDivKind == AEK_INVALID)
387     return false;
388 
389   if (HWDivKind & AEK_HWDIVARM)
390     Features.push_back("+hwdiv-arm");
391   else
392     Features.push_back("-hwdiv-arm");
393 
394   if (HWDivKind & AEK_HWDIVTHUMB)
395     Features.push_back("+hwdiv");
396   else
397     Features.push_back("-hwdiv");
398 
399   return true;
400 }
401 
402 bool ARM::getExtensionFeatures(uint64_t Extensions,
403                                std::vector<StringRef> &Features) {
404 
405   if (Extensions == AEK_INVALID)
406     return false;
407 
408   for (const auto AE : ARCHExtNames) {
409     if ((Extensions & AE.ID) == AE.ID && AE.Feature)
410       Features.push_back(AE.Feature);
411     else if (AE.NegFeature)
412       Features.push_back(AE.NegFeature);
413   }
414 
415   return getHWDivFeatures(Extensions, Features);
416 }
417 
418 StringRef ARM::getArchName(ARM::ArchKind AK) {
419   return ARCHNames[static_cast<unsigned>(AK)].getName();
420 }
421 
422 StringRef ARM::getCPUAttr(ARM::ArchKind AK) {
423   return ARCHNames[static_cast<unsigned>(AK)].getCPUAttr();
424 }
425 
426 StringRef ARM::getSubArch(ARM::ArchKind AK) {
427   return ARCHNames[static_cast<unsigned>(AK)].getSubArch();
428 }
429 
430 unsigned ARM::getArchAttr(ARM::ArchKind AK) {
431   return ARCHNames[static_cast<unsigned>(AK)].ArchAttr;
432 }
433 
434 StringRef ARM::getArchExtName(uint64_t ArchExtKind) {
435   for (const auto AE : ARCHExtNames) {
436     if (ArchExtKind == AE.ID)
437       return AE.getName();
438   }
439   return StringRef();
440 }
441 
442 static bool stripNegationPrefix(StringRef &Name) {
443   if (Name.startswith("no")) {
444     Name = Name.substr(2);
445     return true;
446   }
447   return false;
448 }
449 
450 StringRef ARM::getArchExtFeature(StringRef ArchExt) {
451   bool Negated = stripNegationPrefix(ArchExt);
452   for (const auto AE : ARCHExtNames) {
453     if (AE.Feature && ArchExt == AE.getName())
454       return StringRef(Negated ? AE.NegFeature : AE.Feature);
455   }
456 
457   return StringRef();
458 }
459 
460 static unsigned findDoublePrecisionFPU(unsigned InputFPUKind) {
461   const ARM::FPUName &InputFPU = ARM::FPUNames[InputFPUKind];
462 
463   // If the input FPU already supports double-precision, then there
464   // isn't any different FPU we can return here.
465   //
466   // The current available FPURestriction values are None (no
467   // restriction), D16 (only 16 d-regs) and SP_D16 (16 d-regs
468   // and single precision only); there's no value representing
469   // SP restriction without D16. So this test just means 'is it
470   // SP only?'.
471   if (InputFPU.Restriction != ARM::FPURestriction::SP_D16)
472     return ARM::FK_INVALID;
473 
474   // Otherwise, look for an FPU entry with all the same fields, except
475   // that SP_D16 has been replaced with just D16, representing adding
476   // double precision and not changing anything else.
477   for (const ARM::FPUName &CandidateFPU : ARM::FPUNames) {
478     if (CandidateFPU.FPUVer == InputFPU.FPUVer &&
479         CandidateFPU.NeonSupport == InputFPU.NeonSupport &&
480         CandidateFPU.Restriction == ARM::FPURestriction::D16) {
481       return CandidateFPU.ID;
482     }
483   }
484 
485   // nothing found
486   return ARM::FK_INVALID;
487 }
488 
489 bool ARM::appendArchExtFeatures(
490   StringRef CPU, ARM::ArchKind AK, StringRef ArchExt,
491   std::vector<StringRef> &Features) {
492 
493   size_t StartingNumFeatures = Features.size();
494   const bool Negated = stripNegationPrefix(ArchExt);
495   uint64_t ID = parseArchExt(ArchExt);
496 
497   if (ID == AEK_INVALID)
498     return false;
499 
500   for (const auto AE : ARCHExtNames) {
501     if (Negated) {
502       if ((AE.ID & ID) == ID && AE.NegFeature)
503         Features.push_back(AE.NegFeature);
504     } else {
505       if ((AE.ID & ID) == AE.ID && AE.Feature)
506         Features.push_back(AE.Feature);
507     }
508   }
509 
510   if (CPU == "")
511     CPU = "generic";
512 
513   if (ArchExt == "fp" || ArchExt == "fp.dp") {
514     unsigned FPUKind;
515     if (ArchExt == "fp.dp") {
516       if (Negated) {
517         Features.push_back("-fp64");
518         return true;
519       }
520       FPUKind = findDoublePrecisionFPU(getDefaultFPU(CPU, AK));
521     } else if (Negated) {
522       FPUKind = ARM::FK_NONE;
523     } else {
524       FPUKind = getDefaultFPU(CPU, AK);
525     }
526     return ARM::getFPUFeatures(FPUKind, Features);
527   }
528   return StartingNumFeatures != Features.size();
529 }
530 
531 StringRef ARM::getHWDivName(uint64_t HWDivKind) {
532   for (const auto D : HWDivNames) {
533     if (HWDivKind == D.ID)
534       return D.getName();
535   }
536   return StringRef();
537 }
538 
539 StringRef ARM::getDefaultCPU(StringRef Arch) {
540   ArchKind AK = parseArch(Arch);
541   if (AK == ArchKind::INVALID)
542     return StringRef();
543 
544   // Look for multiple AKs to find the default for pair AK+Name.
545   for (const auto CPU : CPUNames) {
546     if (CPU.ArchID == AK && CPU.Default)
547       return CPU.getName();
548   }
549 
550   // If we can't find a default then target the architecture instead
551   return "generic";
552 }
553 
554 uint64_t ARM::parseHWDiv(StringRef HWDiv) {
555   StringRef Syn = getHWDivSynonym(HWDiv);
556   for (const auto D : HWDivNames) {
557     if (Syn == D.getName())
558       return D.ID;
559   }
560   return AEK_INVALID;
561 }
562 
563 uint64_t ARM::parseArchExt(StringRef ArchExt) {
564   for (const auto A : ARCHExtNames) {
565     if (ArchExt == A.getName())
566       return A.ID;
567   }
568   return AEK_INVALID;
569 }
570 
571 ARM::ArchKind ARM::parseCPUArch(StringRef CPU) {
572   for (const auto C : CPUNames) {
573     if (CPU == C.getName())
574       return C.ArchID;
575   }
576   return ArchKind::INVALID;
577 }
578 
579 void ARM::fillValidCPUArchList(SmallVectorImpl<StringRef> &Values) {
580   for (const CpuNames<ArchKind> &Arch : CPUNames) {
581     if (Arch.ArchID != ArchKind::INVALID)
582       Values.push_back(Arch.getName());
583   }
584 }
585 
586 StringRef ARM::computeDefaultTargetABI(const Triple &TT, StringRef CPU) {
587   StringRef ArchName =
588       CPU.empty() ? TT.getArchName() : getArchName(parseCPUArch(CPU));
589 
590   if (TT.isOSBinFormatMachO()) {
591     if (TT.getEnvironment() == Triple::EABI ||
592         TT.getOS() == Triple::UnknownOS ||
593         parseArchProfile(ArchName) == ProfileKind::M)
594       return "aapcs";
595     if (TT.isWatchABI())
596       return "aapcs16";
597     return "apcs-gnu";
598   } else if (TT.isOSWindows())
599     // FIXME: this is invalid for WindowsCE.
600     return "aapcs";
601 
602   // Select the default based on the platform.
603   switch (TT.getEnvironment()) {
604   case Triple::Android:
605   case Triple::GNUEABI:
606   case Triple::GNUEABIHF:
607   case Triple::MuslEABI:
608   case Triple::MuslEABIHF:
609     return "aapcs-linux";
610   case Triple::EABIHF:
611   case Triple::EABI:
612     return "aapcs";
613   default:
614     if (TT.isOSNetBSD())
615       return "apcs-gnu";
616     if (TT.isOSOpenBSD())
617       return "aapcs-linux";
618     return "aapcs";
619   }
620 }
621