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::ARMV8_6A:
78   case ArchKind::ARMV8R:
79   case ArchKind::ARMV8MBaseline:
80   case ArchKind::ARMV8MMainline:
81   case ArchKind::ARMV8_1MMainline:
82     return 8;
83   case ArchKind::INVALID:
84     return 0;
85   }
86   llvm_unreachable("Unhandled architecture");
87 }
88 
89 // Profile A/R/M
90 ARM::ProfileKind ARM::parseArchProfile(StringRef Arch) {
91   Arch = getCanonicalArchName(Arch);
92   switch (parseArch(Arch)) {
93   case ArchKind::ARMV6M:
94   case ArchKind::ARMV7M:
95   case ArchKind::ARMV7EM:
96   case ArchKind::ARMV8MMainline:
97   case ArchKind::ARMV8MBaseline:
98   case ArchKind::ARMV8_1MMainline:
99     return ProfileKind::M;
100   case ArchKind::ARMV7R:
101   case ArchKind::ARMV8R:
102     return ProfileKind::R;
103   case ArchKind::ARMV7A:
104   case ArchKind::ARMV7VE:
105   case ArchKind::ARMV7K:
106   case ArchKind::ARMV8A:
107   case ArchKind::ARMV8_1A:
108   case ArchKind::ARMV8_2A:
109   case ArchKind::ARMV8_3A:
110   case ArchKind::ARMV8_4A:
111   case ArchKind::ARMV8_5A:
112   case ArchKind::ARMV8_6A:
113     return ProfileKind::A;
114   case ArchKind::ARMV2:
115   case ArchKind::ARMV2A:
116   case ArchKind::ARMV3:
117   case ArchKind::ARMV3M:
118   case ArchKind::ARMV4:
119   case ArchKind::ARMV4T:
120   case ArchKind::ARMV5T:
121   case ArchKind::ARMV5TE:
122   case ArchKind::ARMV5TEJ:
123   case ArchKind::ARMV6:
124   case ArchKind::ARMV6K:
125   case ArchKind::ARMV6T2:
126   case ArchKind::ARMV6KZ:
127   case ArchKind::ARMV7S:
128   case ArchKind::IWMMXT:
129   case ArchKind::IWMMXT2:
130   case ArchKind::XSCALE:
131   case ArchKind::INVALID:
132     return ProfileKind::INVALID;
133   }
134   llvm_unreachable("Unhandled architecture");
135 }
136 
137 StringRef ARM::getArchSynonym(StringRef Arch) {
138   return StringSwitch<StringRef>(Arch)
139       .Case("v5", "v5t")
140       .Case("v5e", "v5te")
141       .Case("v6j", "v6")
142       .Case("v6hl", "v6k")
143       .Cases("v6m", "v6sm", "v6s-m", "v6-m")
144       .Cases("v6z", "v6zk", "v6kz")
145       .Cases("v7", "v7a", "v7hl", "v7l", "v7-a")
146       .Case("v7r", "v7-r")
147       .Case("v7m", "v7-m")
148       .Case("v7em", "v7e-m")
149       .Cases("v8", "v8a", "v8l", "aarch64", "arm64", "v8-a")
150       .Case("v8.1a", "v8.1-a")
151       .Case("v8.2a", "v8.2-a")
152       .Case("v8.3a", "v8.3-a")
153       .Case("v8.4a", "v8.4-a")
154       .Case("v8.5a", "v8.5-a")
155       .Case("v8.6a", "v8.6-a")
156       .Case("v8r", "v8-r")
157       .Case("v8m.base", "v8-m.base")
158       .Case("v8m.main", "v8-m.main")
159       .Case("v8.1m.main", "v8.1-m.main")
160       .Default(Arch);
161 }
162 
163 bool ARM::getFPUFeatures(unsigned FPUKind, std::vector<StringRef> &Features) {
164 
165   if (FPUKind >= FK_LAST || FPUKind == FK_INVALID)
166     return false;
167 
168   static const struct FPUFeatureNameInfo {
169     const char *PlusName, *MinusName;
170     FPUVersion MinVersion;
171     FPURestriction MaxRestriction;
172   } FPUFeatureInfoList[] = {
173     // We have to specify the + and - versions of the name in full so
174     // that we can return them as static StringRefs.
175     //
176     // Also, the SubtargetFeatures ending in just "sp" are listed here
177     // under FPURestriction::None, which is the only FPURestriction in
178     // which they would be valid (since FPURestriction::SP doesn't
179     // exist).
180     {"+vfp2", "-vfp2", FPUVersion::VFPV2, FPURestriction::D16},
181     {"+vfp2sp", "-vfp2sp", FPUVersion::VFPV2, FPURestriction::SP_D16},
182     {"+vfp3", "-vfp3", FPUVersion::VFPV3, FPURestriction::None},
183     {"+vfp3d16", "-vfp3d16", FPUVersion::VFPV3, FPURestriction::D16},
184     {"+vfp3d16sp", "-vfp3d16sp", FPUVersion::VFPV3, FPURestriction::SP_D16},
185     {"+vfp3sp", "-vfp3sp", FPUVersion::VFPV3, FPURestriction::None},
186     {"+fp16", "-fp16", FPUVersion::VFPV3_FP16, FPURestriction::SP_D16},
187     {"+vfp4", "-vfp4", FPUVersion::VFPV4, FPURestriction::None},
188     {"+vfp4d16", "-vfp4d16", FPUVersion::VFPV4, FPURestriction::D16},
189     {"+vfp4d16sp", "-vfp4d16sp", FPUVersion::VFPV4, FPURestriction::SP_D16},
190     {"+vfp4sp", "-vfp4sp", FPUVersion::VFPV4, FPURestriction::None},
191     {"+fp-armv8", "-fp-armv8", FPUVersion::VFPV5, FPURestriction::None},
192     {"+fp-armv8d16", "-fp-armv8d16", FPUVersion::VFPV5, FPURestriction::D16},
193     {"+fp-armv8d16sp", "-fp-armv8d16sp", FPUVersion::VFPV5, FPURestriction::SP_D16},
194     {"+fp-armv8sp", "-fp-armv8sp", FPUVersion::VFPV5, FPURestriction::None},
195     {"+fullfp16", "-fullfp16", FPUVersion::VFPV5_FULLFP16, FPURestriction::SP_D16},
196     {"+fp64", "-fp64", FPUVersion::VFPV2, FPURestriction::D16},
197     {"+d32", "-d32", FPUVersion::VFPV3, FPURestriction::None},
198   };
199 
200   for (const auto &Info: FPUFeatureInfoList) {
201     if (FPUNames[FPUKind].FPUVer >= Info.MinVersion &&
202         FPUNames[FPUKind].Restriction <= Info.MaxRestriction)
203       Features.push_back(Info.PlusName);
204     else
205       Features.push_back(Info.MinusName);
206   }
207 
208   static const struct NeonFeatureNameInfo {
209     const char *PlusName, *MinusName;
210     NeonSupportLevel MinSupportLevel;
211   } NeonFeatureInfoList[] = {
212     {"+neon", "-neon", NeonSupportLevel::Neon},
213     {"+crypto", "-crypto", NeonSupportLevel::Crypto},
214   };
215 
216   for (const auto &Info: NeonFeatureInfoList) {
217     if (FPUNames[FPUKind].NeonSupport >= Info.MinSupportLevel)
218       Features.push_back(Info.PlusName);
219     else
220       Features.push_back(Info.MinusName);
221   }
222 
223   return true;
224 }
225 
226 // Little/Big endian
227 ARM::EndianKind ARM::parseArchEndian(StringRef Arch) {
228   if (Arch.startswith("armeb") || Arch.startswith("thumbeb") ||
229       Arch.startswith("aarch64_be"))
230     return EndianKind::BIG;
231 
232   if (Arch.startswith("arm") || Arch.startswith("thumb")) {
233     if (Arch.endswith("eb"))
234       return EndianKind::BIG;
235     else
236       return EndianKind::LITTLE;
237   }
238 
239   if (Arch.startswith("aarch64") || Arch.startswith("aarch64_32"))
240     return EndianKind::LITTLE;
241 
242   return EndianKind::INVALID;
243 }
244 
245 // ARM, Thumb, AArch64
246 ARM::ISAKind ARM::parseArchISA(StringRef Arch) {
247   return StringSwitch<ISAKind>(Arch)
248       .StartsWith("aarch64", ISAKind::AARCH64)
249       .StartsWith("arm64", ISAKind::AARCH64)
250       .StartsWith("thumb", ISAKind::THUMB)
251       .StartsWith("arm", ISAKind::ARM)
252       .Default(ISAKind::INVALID);
253 }
254 
255 unsigned ARM::parseFPU(StringRef FPU) {
256   StringRef Syn = getFPUSynonym(FPU);
257   for (const auto F : FPUNames) {
258     if (Syn == F.getName())
259       return F.ID;
260   }
261   return FK_INVALID;
262 }
263 
264 ARM::NeonSupportLevel ARM::getFPUNeonSupportLevel(unsigned FPUKind) {
265   if (FPUKind >= FK_LAST)
266     return NeonSupportLevel::None;
267   return FPUNames[FPUKind].NeonSupport;
268 }
269 
270 // MArch is expected to be of the form (arm|thumb)?(eb)?(v.+)?(eb)?, but
271 // (iwmmxt|xscale)(eb)? is also permitted. If the former, return
272 // "v.+", if the latter, return unmodified string, minus 'eb'.
273 // If invalid, return empty string.
274 StringRef ARM::getCanonicalArchName(StringRef Arch) {
275   size_t offset = StringRef::npos;
276   StringRef A = Arch;
277   StringRef Error = "";
278 
279   // Begins with "arm" / "thumb", move past it.
280   if (A.startswith("arm64_32"))
281     offset = 8;
282   else if (A.startswith("arm64"))
283     offset = 5;
284   else if (A.startswith("aarch64_32"))
285     offset = 10;
286   else if (A.startswith("arm"))
287     offset = 3;
288   else if (A.startswith("thumb"))
289     offset = 5;
290   else if (A.startswith("aarch64")) {
291     offset = 7;
292     // AArch64 uses "_be", not "eb" suffix.
293     if (A.find("eb") != StringRef::npos)
294       return Error;
295     if (A.substr(offset, 3) == "_be")
296       offset += 3;
297   }
298 
299   // Ex. "armebv7", move past the "eb".
300   if (offset != StringRef::npos && A.substr(offset, 2) == "eb")
301     offset += 2;
302   // Or, if it ends with eb ("armv7eb"), chop it off.
303   else if (A.endswith("eb"))
304     A = A.substr(0, A.size() - 2);
305   // Trim the head
306   if (offset != StringRef::npos)
307     A = A.substr(offset);
308 
309   // Empty string means offset reached the end, which means it's valid.
310   if (A.empty())
311     return Arch;
312 
313   // Only match non-marketing names
314   if (offset != StringRef::npos) {
315     // Must start with 'vN'.
316     if (A.size() >= 2 && (A[0] != 'v' || !std::isdigit(A[1])))
317       return Error;
318     // Can't have an extra 'eb'.
319     if (A.find("eb") != StringRef::npos)
320       return Error;
321   }
322 
323   // Arch will either be a 'v' name (v7a) or a marketing name (xscale).
324   return A;
325 }
326 
327 StringRef ARM::getFPUSynonym(StringRef FPU) {
328   return StringSwitch<StringRef>(FPU)
329       .Cases("fpa", "fpe2", "fpe3", "maverick", "invalid") // Unsupported
330       .Case("vfp2", "vfpv2")
331       .Case("vfp3", "vfpv3")
332       .Case("vfp4", "vfpv4")
333       .Case("vfp3-d16", "vfpv3-d16")
334       .Case("vfp4-d16", "vfpv4-d16")
335       .Cases("fp4-sp-d16", "vfpv4-sp-d16", "fpv4-sp-d16")
336       .Cases("fp4-dp-d16", "fpv4-dp-d16", "vfpv4-d16")
337       .Case("fp5-sp-d16", "fpv5-sp-d16")
338       .Cases("fp5-dp-d16", "fpv5-dp-d16", "fpv5-d16")
339       // FIXME: Clang uses it, but it's bogus, since neon defaults to vfpv3.
340       .Case("neon-vfpv3", "neon")
341       .Default(FPU);
342 }
343 
344 StringRef ARM::getFPUName(unsigned FPUKind) {
345   if (FPUKind >= FK_LAST)
346     return StringRef();
347   return FPUNames[FPUKind].getName();
348 }
349 
350 ARM::FPUVersion ARM::getFPUVersion(unsigned FPUKind) {
351   if (FPUKind >= FK_LAST)
352     return FPUVersion::NONE;
353   return FPUNames[FPUKind].FPUVer;
354 }
355 
356 ARM::FPURestriction ARM::getFPURestriction(unsigned FPUKind) {
357   if (FPUKind >= FK_LAST)
358     return FPURestriction::None;
359   return FPUNames[FPUKind].Restriction;
360 }
361 
362 unsigned ARM::getDefaultFPU(StringRef CPU, ARM::ArchKind AK) {
363   if (CPU == "generic")
364     return ARM::ARCHNames[static_cast<unsigned>(AK)].DefaultFPU;
365 
366   return StringSwitch<unsigned>(CPU)
367 #define ARM_CPU_NAME(NAME, ID, DEFAULT_FPU, IS_DEFAULT, DEFAULT_EXT)           \
368   .Case(NAME, DEFAULT_FPU)
369 #include "llvm/Support/ARMTargetParser.def"
370    .Default(ARM::FK_INVALID);
371 }
372 
373 uint64_t ARM::getDefaultExtensions(StringRef CPU, ARM::ArchKind AK) {
374   if (CPU == "generic")
375     return ARM::ARCHNames[static_cast<unsigned>(AK)].ArchBaseExtensions;
376 
377   return StringSwitch<uint64_t>(CPU)
378 #define ARM_CPU_NAME(NAME, ID, DEFAULT_FPU, IS_DEFAULT, DEFAULT_EXT)           \
379   .Case(NAME,                                                                  \
380         ARCHNames[static_cast<unsigned>(ArchKind::ID)].ArchBaseExtensions |    \
381             DEFAULT_EXT)
382 #include "llvm/Support/ARMTargetParser.def"
383   .Default(ARM::AEK_INVALID);
384 }
385 
386 bool ARM::getHWDivFeatures(uint64_t HWDivKind,
387                            std::vector<StringRef> &Features) {
388 
389   if (HWDivKind == AEK_INVALID)
390     return false;
391 
392   if (HWDivKind & AEK_HWDIVARM)
393     Features.push_back("+hwdiv-arm");
394   else
395     Features.push_back("-hwdiv-arm");
396 
397   if (HWDivKind & AEK_HWDIVTHUMB)
398     Features.push_back("+hwdiv");
399   else
400     Features.push_back("-hwdiv");
401 
402   return true;
403 }
404 
405 bool ARM::getExtensionFeatures(uint64_t Extensions,
406                                std::vector<StringRef> &Features) {
407 
408   if (Extensions == AEK_INVALID)
409     return false;
410 
411   for (const auto AE : ARCHExtNames) {
412     if ((Extensions & AE.ID) == AE.ID && AE.Feature)
413       Features.push_back(AE.Feature);
414     else if (AE.NegFeature)
415       Features.push_back(AE.NegFeature);
416   }
417 
418   return getHWDivFeatures(Extensions, Features);
419 }
420 
421 StringRef ARM::getArchName(ARM::ArchKind AK) {
422   return ARCHNames[static_cast<unsigned>(AK)].getName();
423 }
424 
425 StringRef ARM::getCPUAttr(ARM::ArchKind AK) {
426   return ARCHNames[static_cast<unsigned>(AK)].getCPUAttr();
427 }
428 
429 StringRef ARM::getSubArch(ARM::ArchKind AK) {
430   return ARCHNames[static_cast<unsigned>(AK)].getSubArch();
431 }
432 
433 unsigned ARM::getArchAttr(ARM::ArchKind AK) {
434   return ARCHNames[static_cast<unsigned>(AK)].ArchAttr;
435 }
436 
437 StringRef ARM::getArchExtName(uint64_t ArchExtKind) {
438   for (const auto AE : ARCHExtNames) {
439     if (ArchExtKind == AE.ID)
440       return AE.getName();
441   }
442   return StringRef();
443 }
444 
445 static bool stripNegationPrefix(StringRef &Name) {
446   if (Name.startswith("no")) {
447     Name = Name.substr(2);
448     return true;
449   }
450   return false;
451 }
452 
453 StringRef ARM::getArchExtFeature(StringRef ArchExt) {
454   bool Negated = stripNegationPrefix(ArchExt);
455   for (const auto AE : ARCHExtNames) {
456     if (AE.Feature && ArchExt == AE.getName())
457       return StringRef(Negated ? AE.NegFeature : AE.Feature);
458   }
459 
460   return StringRef();
461 }
462 
463 static unsigned findDoublePrecisionFPU(unsigned InputFPUKind) {
464   const ARM::FPUName &InputFPU = ARM::FPUNames[InputFPUKind];
465 
466   // If the input FPU already supports double-precision, then there
467   // isn't any different FPU we can return here.
468   //
469   // The current available FPURestriction values are None (no
470   // restriction), D16 (only 16 d-regs) and SP_D16 (16 d-regs
471   // and single precision only); there's no value representing
472   // SP restriction without D16. So this test just means 'is it
473   // SP only?'.
474   if (InputFPU.Restriction != ARM::FPURestriction::SP_D16)
475     return ARM::FK_INVALID;
476 
477   // Otherwise, look for an FPU entry with all the same fields, except
478   // that SP_D16 has been replaced with just D16, representing adding
479   // double precision and not changing anything else.
480   for (const ARM::FPUName &CandidateFPU : ARM::FPUNames) {
481     if (CandidateFPU.FPUVer == InputFPU.FPUVer &&
482         CandidateFPU.NeonSupport == InputFPU.NeonSupport &&
483         CandidateFPU.Restriction == ARM::FPURestriction::D16) {
484       return CandidateFPU.ID;
485     }
486   }
487 
488   // nothing found
489   return ARM::FK_INVALID;
490 }
491 
492 bool ARM::appendArchExtFeatures(
493   StringRef CPU, ARM::ArchKind AK, StringRef ArchExt,
494   std::vector<StringRef> &Features) {
495 
496   size_t StartingNumFeatures = Features.size();
497   const bool Negated = stripNegationPrefix(ArchExt);
498   uint64_t ID = parseArchExt(ArchExt);
499 
500   if (ID == AEK_INVALID)
501     return false;
502 
503   for (const auto AE : ARCHExtNames) {
504     if (Negated) {
505       if ((AE.ID & ID) == ID && AE.NegFeature)
506         Features.push_back(AE.NegFeature);
507     } else {
508       if ((AE.ID & ID) == AE.ID && AE.Feature)
509         Features.push_back(AE.Feature);
510     }
511   }
512 
513   if (CPU == "")
514     CPU = "generic";
515 
516   if (ArchExt == "fp" || ArchExt == "fp.dp") {
517     unsigned FPUKind;
518     if (ArchExt == "fp.dp") {
519       if (Negated) {
520         Features.push_back("-fp64");
521         return true;
522       }
523       FPUKind = findDoublePrecisionFPU(getDefaultFPU(CPU, AK));
524     } else if (Negated) {
525       FPUKind = ARM::FK_NONE;
526     } else {
527       FPUKind = getDefaultFPU(CPU, AK);
528     }
529     return ARM::getFPUFeatures(FPUKind, Features);
530   }
531   return StartingNumFeatures != Features.size();
532 }
533 
534 StringRef ARM::getHWDivName(uint64_t HWDivKind) {
535   for (const auto D : HWDivNames) {
536     if (HWDivKind == D.ID)
537       return D.getName();
538   }
539   return StringRef();
540 }
541 
542 StringRef ARM::getDefaultCPU(StringRef Arch) {
543   ArchKind AK = parseArch(Arch);
544   if (AK == ArchKind::INVALID)
545     return StringRef();
546 
547   // Look for multiple AKs to find the default for pair AK+Name.
548   for (const auto CPU : CPUNames) {
549     if (CPU.ArchID == AK && CPU.Default)
550       return CPU.getName();
551   }
552 
553   // If we can't find a default then target the architecture instead
554   return "generic";
555 }
556 
557 uint64_t ARM::parseHWDiv(StringRef HWDiv) {
558   StringRef Syn = getHWDivSynonym(HWDiv);
559   for (const auto D : HWDivNames) {
560     if (Syn == D.getName())
561       return D.ID;
562   }
563   return AEK_INVALID;
564 }
565 
566 uint64_t ARM::parseArchExt(StringRef ArchExt) {
567   for (const auto A : ARCHExtNames) {
568     if (ArchExt == A.getName())
569       return A.ID;
570   }
571   return AEK_INVALID;
572 }
573 
574 ARM::ArchKind ARM::parseCPUArch(StringRef CPU) {
575   for (const auto C : CPUNames) {
576     if (CPU == C.getName())
577       return C.ArchID;
578   }
579   return ArchKind::INVALID;
580 }
581 
582 void ARM::fillValidCPUArchList(SmallVectorImpl<StringRef> &Values) {
583   for (const CpuNames<ArchKind> &Arch : CPUNames) {
584     if (Arch.ArchID != ArchKind::INVALID)
585       Values.push_back(Arch.getName());
586   }
587 }
588 
589 StringRef ARM::computeDefaultTargetABI(const Triple &TT, StringRef CPU) {
590   StringRef ArchName =
591       CPU.empty() ? TT.getArchName() : getArchName(parseCPUArch(CPU));
592 
593   if (TT.isOSBinFormatMachO()) {
594     if (TT.getEnvironment() == Triple::EABI ||
595         TT.getOS() == Triple::UnknownOS ||
596         parseArchProfile(ArchName) == ProfileKind::M)
597       return "aapcs";
598     if (TT.isWatchABI())
599       return "aapcs16";
600     return "apcs-gnu";
601   } else if (TT.isOSWindows())
602     // FIXME: this is invalid for WindowsCE.
603     return "aapcs";
604 
605   // Select the default based on the platform.
606   switch (TT.getEnvironment()) {
607   case Triple::Android:
608   case Triple::GNUEABI:
609   case Triple::GNUEABIHF:
610   case Triple::MuslEABI:
611   case Triple::MuslEABIHF:
612     return "aapcs-linux";
613   case Triple::EABIHF:
614   case Triple::EABI:
615     return "aapcs";
616   default:
617     if (TT.isOSNetBSD())
618       return "apcs-gnu";
619     if (TT.isOSOpenBSD())
620       return "aapcs-linux";
621     return "aapcs";
622   }
623 }
624