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 "llvm/ADT/Triple.h"
17 #include <cctype>
18 
19 using namespace llvm;
20 
21 static StringRef getHWDivSynonym(StringRef HWDiv) {
22   return StringSwitch<StringRef>(HWDiv)
23       .Case("thumb,arm", "arm,thumb")
24       .Default(HWDiv);
25 }
26 
27 // Allows partial match, ex. "v7a" matches "armv7a".
28 ARM::ArchKind ARM::parseArch(StringRef Arch) {
29   Arch = getCanonicalArchName(Arch);
30   StringRef Syn = getArchSynonym(Arch);
31   for (const auto &A : ARCHNames) {
32     if (A.getName().endswith(Syn))
33       return A.ID;
34   }
35   return ArchKind::INVALID;
36 }
37 
38 // Version number (ex. v7 = 7).
39 unsigned ARM::parseArchVersion(StringRef Arch) {
40   Arch = getCanonicalArchName(Arch);
41   switch (parseArch(Arch)) {
42   case ArchKind::ARMV2:
43   case ArchKind::ARMV2A:
44     return 2;
45   case ArchKind::ARMV3:
46   case ArchKind::ARMV3M:
47     return 3;
48   case ArchKind::ARMV4:
49   case ArchKind::ARMV4T:
50     return 4;
51   case ArchKind::ARMV5T:
52   case ArchKind::ARMV5TE:
53   case ArchKind::IWMMXT:
54   case ArchKind::IWMMXT2:
55   case ArchKind::XSCALE:
56   case ArchKind::ARMV5TEJ:
57     return 5;
58   case ArchKind::ARMV6:
59   case ArchKind::ARMV6K:
60   case ArchKind::ARMV6T2:
61   case ArchKind::ARMV6KZ:
62   case ArchKind::ARMV6M:
63     return 6;
64   case ArchKind::ARMV7A:
65   case ArchKind::ARMV7VE:
66   case ArchKind::ARMV7R:
67   case ArchKind::ARMV7M:
68   case ArchKind::ARMV7S:
69   case ArchKind::ARMV7EM:
70   case ArchKind::ARMV7K:
71     return 7;
72   case ArchKind::ARMV8A:
73   case ArchKind::ARMV8_1A:
74   case ArchKind::ARMV8_2A:
75   case ArchKind::ARMV8_3A:
76   case ArchKind::ARMV8_4A:
77   case ArchKind::ARMV8_5A:
78   case ArchKind::ARMV8_6A:
79   case ArchKind::ARMV8_7A:
80   case ArchKind::ARMV8R:
81   case ArchKind::ARMV8MBaseline:
82   case ArchKind::ARMV8MMainline:
83   case ArchKind::ARMV8_1MMainline:
84     return 8;
85   case ArchKind::INVALID:
86     return 0;
87   }
88   llvm_unreachable("Unhandled architecture");
89 }
90 
91 // Profile A/R/M
92 ARM::ProfileKind ARM::parseArchProfile(StringRef Arch) {
93   Arch = getCanonicalArchName(Arch);
94   switch (parseArch(Arch)) {
95   case ArchKind::ARMV6M:
96   case ArchKind::ARMV7M:
97   case ArchKind::ARMV7EM:
98   case ArchKind::ARMV8MMainline:
99   case ArchKind::ARMV8MBaseline:
100   case ArchKind::ARMV8_1MMainline:
101     return ProfileKind::M;
102   case ArchKind::ARMV7R:
103   case ArchKind::ARMV8R:
104     return ProfileKind::R;
105   case ArchKind::ARMV7A:
106   case ArchKind::ARMV7VE:
107   case ArchKind::ARMV7K:
108   case ArchKind::ARMV8A:
109   case ArchKind::ARMV8_1A:
110   case ArchKind::ARMV8_2A:
111   case ArchKind::ARMV8_3A:
112   case ArchKind::ARMV8_4A:
113   case ArchKind::ARMV8_5A:
114   case ArchKind::ARMV8_6A:
115   case ArchKind::ARMV8_7A:
116     return ProfileKind::A;
117   case ArchKind::ARMV2:
118   case ArchKind::ARMV2A:
119   case ArchKind::ARMV3:
120   case ArchKind::ARMV3M:
121   case ArchKind::ARMV4:
122   case ArchKind::ARMV4T:
123   case ArchKind::ARMV5T:
124   case ArchKind::ARMV5TE:
125   case ArchKind::ARMV5TEJ:
126   case ArchKind::ARMV6:
127   case ArchKind::ARMV6K:
128   case ArchKind::ARMV6T2:
129   case ArchKind::ARMV6KZ:
130   case ArchKind::ARMV7S:
131   case ArchKind::IWMMXT:
132   case ArchKind::IWMMXT2:
133   case ArchKind::XSCALE:
134   case ArchKind::INVALID:
135     return ProfileKind::INVALID;
136   }
137   llvm_unreachable("Unhandled architecture");
138 }
139 
140 StringRef ARM::getArchSynonym(StringRef Arch) {
141   return StringSwitch<StringRef>(Arch)
142       .Case("v5", "v5t")
143       .Case("v5e", "v5te")
144       .Case("v6j", "v6")
145       .Case("v6hl", "v6k")
146       .Cases("v6m", "v6sm", "v6s-m", "v6-m")
147       .Cases("v6z", "v6zk", "v6kz")
148       .Cases("v7", "v7a", "v7hl", "v7l", "v7-a")
149       .Case("v7r", "v7-r")
150       .Case("v7m", "v7-m")
151       .Case("v7em", "v7e-m")
152       .Cases("v8", "v8a", "v8l", "aarch64", "arm64", "v8-a")
153       .Case("v8.1a", "v8.1-a")
154       .Case("v8.2a", "v8.2-a")
155       .Case("v8.3a", "v8.3-a")
156       .Case("v8.4a", "v8.4-a")
157       .Case("v8.5a", "v8.5-a")
158       .Case("v8.6a", "v8.6-a")
159       .Case("v8.7a", "v8.7-a")
160       .Case("v8r", "v8-r")
161       .Case("v8m.base", "v8-m.base")
162       .Case("v8m.main", "v8-m.main")
163       .Case("v8.1m.main", "v8.1-m.main")
164       .Default(Arch);
165 }
166 
167 bool ARM::getFPUFeatures(unsigned FPUKind, std::vector<StringRef> &Features) {
168 
169   if (FPUKind >= FK_LAST || FPUKind == FK_INVALID)
170     return false;
171 
172   static const struct FPUFeatureNameInfo {
173     const char *PlusName, *MinusName;
174     FPUVersion MinVersion;
175     FPURestriction MaxRestriction;
176   } FPUFeatureInfoList[] = {
177     // We have to specify the + and - versions of the name in full so
178     // that we can return them as static StringRefs.
179     //
180     // Also, the SubtargetFeatures ending in just "sp" are listed here
181     // under FPURestriction::None, which is the only FPURestriction in
182     // which they would be valid (since FPURestriction::SP doesn't
183     // exist).
184     {"+vfp2", "-vfp2", FPUVersion::VFPV2, FPURestriction::D16},
185     {"+vfp2sp", "-vfp2sp", FPUVersion::VFPV2, FPURestriction::SP_D16},
186     {"+vfp3", "-vfp3", FPUVersion::VFPV3, FPURestriction::None},
187     {"+vfp3d16", "-vfp3d16", FPUVersion::VFPV3, FPURestriction::D16},
188     {"+vfp3d16sp", "-vfp3d16sp", FPUVersion::VFPV3, FPURestriction::SP_D16},
189     {"+vfp3sp", "-vfp3sp", FPUVersion::VFPV3, FPURestriction::None},
190     {"+fp16", "-fp16", FPUVersion::VFPV3_FP16, FPURestriction::SP_D16},
191     {"+vfp4", "-vfp4", FPUVersion::VFPV4, FPURestriction::None},
192     {"+vfp4d16", "-vfp4d16", FPUVersion::VFPV4, FPURestriction::D16},
193     {"+vfp4d16sp", "-vfp4d16sp", FPUVersion::VFPV4, FPURestriction::SP_D16},
194     {"+vfp4sp", "-vfp4sp", FPUVersion::VFPV4, FPURestriction::None},
195     {"+fp-armv8", "-fp-armv8", FPUVersion::VFPV5, FPURestriction::None},
196     {"+fp-armv8d16", "-fp-armv8d16", FPUVersion::VFPV5, FPURestriction::D16},
197     {"+fp-armv8d16sp", "-fp-armv8d16sp", FPUVersion::VFPV5, FPURestriction::SP_D16},
198     {"+fp-armv8sp", "-fp-armv8sp", FPUVersion::VFPV5, FPURestriction::None},
199     {"+fullfp16", "-fullfp16", FPUVersion::VFPV5_FULLFP16, FPURestriction::SP_D16},
200     {"+fp64", "-fp64", FPUVersion::VFPV2, FPURestriction::D16},
201     {"+d32", "-d32", FPUVersion::VFPV3, FPURestriction::None},
202   };
203 
204   for (const auto &Info: FPUFeatureInfoList) {
205     if (FPUNames[FPUKind].FPUVer >= Info.MinVersion &&
206         FPUNames[FPUKind].Restriction <= Info.MaxRestriction)
207       Features.push_back(Info.PlusName);
208     else
209       Features.push_back(Info.MinusName);
210   }
211 
212   static const struct NeonFeatureNameInfo {
213     const char *PlusName, *MinusName;
214     NeonSupportLevel MinSupportLevel;
215   } NeonFeatureInfoList[] = {
216       {"+neon", "-neon", NeonSupportLevel::Neon},
217       {"+sha2", "-sha2", NeonSupportLevel::Crypto},
218       {"+aes", "-aes", NeonSupportLevel::Crypto},
219   };
220 
221   for (const auto &Info: NeonFeatureInfoList) {
222     if (FPUNames[FPUKind].NeonSupport >= Info.MinSupportLevel)
223       Features.push_back(Info.PlusName);
224     else
225       Features.push_back(Info.MinusName);
226   }
227 
228   return true;
229 }
230 
231 // Little/Big endian
232 ARM::EndianKind ARM::parseArchEndian(StringRef Arch) {
233   if (Arch.startswith("armeb") || Arch.startswith("thumbeb") ||
234       Arch.startswith("aarch64_be"))
235     return EndianKind::BIG;
236 
237   if (Arch.startswith("arm") || Arch.startswith("thumb")) {
238     if (Arch.endswith("eb"))
239       return EndianKind::BIG;
240     else
241       return EndianKind::LITTLE;
242   }
243 
244   if (Arch.startswith("aarch64") || Arch.startswith("aarch64_32"))
245     return EndianKind::LITTLE;
246 
247   return EndianKind::INVALID;
248 }
249 
250 // ARM, Thumb, AArch64
251 ARM::ISAKind ARM::parseArchISA(StringRef Arch) {
252   return StringSwitch<ISAKind>(Arch)
253       .StartsWith("aarch64", ISAKind::AARCH64)
254       .StartsWith("arm64", ISAKind::AARCH64)
255       .StartsWith("thumb", ISAKind::THUMB)
256       .StartsWith("arm", ISAKind::ARM)
257       .Default(ISAKind::INVALID);
258 }
259 
260 unsigned ARM::parseFPU(StringRef FPU) {
261   StringRef Syn = getFPUSynonym(FPU);
262   for (const auto &F : FPUNames) {
263     if (Syn == F.getName())
264       return F.ID;
265   }
266   return FK_INVALID;
267 }
268 
269 ARM::NeonSupportLevel ARM::getFPUNeonSupportLevel(unsigned FPUKind) {
270   if (FPUKind >= FK_LAST)
271     return NeonSupportLevel::None;
272   return FPUNames[FPUKind].NeonSupport;
273 }
274 
275 // MArch is expected to be of the form (arm|thumb)?(eb)?(v.+)?(eb)?, but
276 // (iwmmxt|xscale)(eb)? is also permitted. If the former, return
277 // "v.+", if the latter, return unmodified string, minus 'eb'.
278 // If invalid, return empty string.
279 StringRef ARM::getCanonicalArchName(StringRef Arch) {
280   size_t offset = StringRef::npos;
281   StringRef A = Arch;
282   StringRef Error = "";
283 
284   // Begins with "arm" / "thumb", move past it.
285   if (A.startswith("arm64_32"))
286     offset = 8;
287   else if (A.startswith("arm64e"))
288     offset = 6;
289   else if (A.startswith("arm64"))
290     offset = 5;
291   else if (A.startswith("aarch64_32"))
292     offset = 10;
293   else if (A.startswith("arm"))
294     offset = 3;
295   else if (A.startswith("thumb"))
296     offset = 5;
297   else if (A.startswith("aarch64")) {
298     offset = 7;
299     // AArch64 uses "_be", not "eb" suffix.
300     if (A.find("eb") != StringRef::npos)
301       return Error;
302     if (A.substr(offset, 3) == "_be")
303       offset += 3;
304   }
305 
306   // Ex. "armebv7", move past the "eb".
307   if (offset != StringRef::npos && A.substr(offset, 2) == "eb")
308     offset += 2;
309   // Or, if it ends with eb ("armv7eb"), chop it off.
310   else if (A.endswith("eb"))
311     A = A.substr(0, A.size() - 2);
312   // Trim the head
313   if (offset != StringRef::npos)
314     A = A.substr(offset);
315 
316   // Empty string means offset reached the end, which means it's valid.
317   if (A.empty())
318     return Arch;
319 
320   // Only match non-marketing names
321   if (offset != StringRef::npos) {
322     // Must start with 'vN'.
323     if (A.size() >= 2 && (A[0] != 'v' || !std::isdigit(A[1])))
324       return Error;
325     // Can't have an extra 'eb'.
326     if (A.find("eb") != StringRef::npos)
327       return Error;
328   }
329 
330   // Arch will either be a 'v' name (v7a) or a marketing name (xscale).
331   return A;
332 }
333 
334 StringRef ARM::getFPUSynonym(StringRef FPU) {
335   return StringSwitch<StringRef>(FPU)
336       .Cases("fpa", "fpe2", "fpe3", "maverick", "invalid") // Unsupported
337       .Case("vfp2", "vfpv2")
338       .Case("vfp3", "vfpv3")
339       .Case("vfp4", "vfpv4")
340       .Case("vfp3-d16", "vfpv3-d16")
341       .Case("vfp4-d16", "vfpv4-d16")
342       .Cases("fp4-sp-d16", "vfpv4-sp-d16", "fpv4-sp-d16")
343       .Cases("fp4-dp-d16", "fpv4-dp-d16", "vfpv4-d16")
344       .Case("fp5-sp-d16", "fpv5-sp-d16")
345       .Cases("fp5-dp-d16", "fpv5-dp-d16", "fpv5-d16")
346       // FIXME: Clang uses it, but it's bogus, since neon defaults to vfpv3.
347       .Case("neon-vfpv3", "neon")
348       .Default(FPU);
349 }
350 
351 StringRef ARM::getFPUName(unsigned FPUKind) {
352   if (FPUKind >= FK_LAST)
353     return StringRef();
354   return FPUNames[FPUKind].getName();
355 }
356 
357 ARM::FPUVersion ARM::getFPUVersion(unsigned FPUKind) {
358   if (FPUKind >= FK_LAST)
359     return FPUVersion::NONE;
360   return FPUNames[FPUKind].FPUVer;
361 }
362 
363 ARM::FPURestriction ARM::getFPURestriction(unsigned FPUKind) {
364   if (FPUKind >= FK_LAST)
365     return FPURestriction::None;
366   return FPUNames[FPUKind].Restriction;
367 }
368 
369 unsigned ARM::getDefaultFPU(StringRef CPU, ARM::ArchKind AK) {
370   if (CPU == "generic")
371     return ARM::ARCHNames[static_cast<unsigned>(AK)].DefaultFPU;
372 
373   return StringSwitch<unsigned>(CPU)
374 #define ARM_CPU_NAME(NAME, ID, DEFAULT_FPU, IS_DEFAULT, DEFAULT_EXT)           \
375   .Case(NAME, DEFAULT_FPU)
376 #include "llvm/Support/ARMTargetParser.def"
377    .Default(ARM::FK_INVALID);
378 }
379 
380 uint64_t ARM::getDefaultExtensions(StringRef CPU, ARM::ArchKind AK) {
381   if (CPU == "generic")
382     return ARM::ARCHNames[static_cast<unsigned>(AK)].ArchBaseExtensions;
383 
384   return StringSwitch<uint64_t>(CPU)
385 #define ARM_CPU_NAME(NAME, ID, DEFAULT_FPU, IS_DEFAULT, DEFAULT_EXT)           \
386   .Case(NAME,                                                                  \
387         ARCHNames[static_cast<unsigned>(ArchKind::ID)].ArchBaseExtensions |    \
388             DEFAULT_EXT)
389 #include "llvm/Support/ARMTargetParser.def"
390   .Default(ARM::AEK_INVALID);
391 }
392 
393 bool ARM::getHWDivFeatures(uint64_t HWDivKind,
394                            std::vector<StringRef> &Features) {
395 
396   if (HWDivKind == AEK_INVALID)
397     return false;
398 
399   if (HWDivKind & AEK_HWDIVARM)
400     Features.push_back("+hwdiv-arm");
401   else
402     Features.push_back("-hwdiv-arm");
403 
404   if (HWDivKind & AEK_HWDIVTHUMB)
405     Features.push_back("+hwdiv");
406   else
407     Features.push_back("-hwdiv");
408 
409   return true;
410 }
411 
412 bool ARM::getExtensionFeatures(uint64_t Extensions,
413                                std::vector<StringRef> &Features) {
414 
415   if (Extensions == AEK_INVALID)
416     return false;
417 
418   for (const auto &AE : ARCHExtNames) {
419     if ((Extensions & AE.ID) == AE.ID && AE.Feature)
420       Features.push_back(AE.Feature);
421     else if (AE.NegFeature)
422       Features.push_back(AE.NegFeature);
423   }
424 
425   return getHWDivFeatures(Extensions, Features);
426 }
427 
428 StringRef ARM::getArchName(ARM::ArchKind AK) {
429   return ARCHNames[static_cast<unsigned>(AK)].getName();
430 }
431 
432 StringRef ARM::getCPUAttr(ARM::ArchKind AK) {
433   return ARCHNames[static_cast<unsigned>(AK)].getCPUAttr();
434 }
435 
436 StringRef ARM::getSubArch(ARM::ArchKind AK) {
437   return ARCHNames[static_cast<unsigned>(AK)].getSubArch();
438 }
439 
440 unsigned ARM::getArchAttr(ARM::ArchKind AK) {
441   return ARCHNames[static_cast<unsigned>(AK)].ArchAttr;
442 }
443 
444 StringRef ARM::getArchExtName(uint64_t ArchExtKind) {
445   for (const auto &AE : ARCHExtNames) {
446     if (ArchExtKind == AE.ID)
447       return AE.getName();
448   }
449   return StringRef();
450 }
451 
452 static bool stripNegationPrefix(StringRef &Name) {
453   if (Name.startswith("no")) {
454     Name = Name.substr(2);
455     return true;
456   }
457   return false;
458 }
459 
460 StringRef ARM::getArchExtFeature(StringRef ArchExt) {
461   bool Negated = stripNegationPrefix(ArchExt);
462   for (const auto &AE : ARCHExtNames) {
463     if (AE.Feature && ArchExt == AE.getName())
464       return StringRef(Negated ? AE.NegFeature : AE.Feature);
465   }
466 
467   return StringRef();
468 }
469 
470 static unsigned findDoublePrecisionFPU(unsigned InputFPUKind) {
471   const ARM::FPUName &InputFPU = ARM::FPUNames[InputFPUKind];
472 
473   // If the input FPU already supports double-precision, then there
474   // isn't any different FPU we can return here.
475   //
476   // The current available FPURestriction values are None (no
477   // restriction), D16 (only 16 d-regs) and SP_D16 (16 d-regs
478   // and single precision only); there's no value representing
479   // SP restriction without D16. So this test just means 'is it
480   // SP only?'.
481   if (InputFPU.Restriction != ARM::FPURestriction::SP_D16)
482     return ARM::FK_INVALID;
483 
484   // Otherwise, look for an FPU entry with all the same fields, except
485   // that SP_D16 has been replaced with just D16, representing adding
486   // double precision and not changing anything else.
487   for (const ARM::FPUName &CandidateFPU : ARM::FPUNames) {
488     if (CandidateFPU.FPUVer == InputFPU.FPUVer &&
489         CandidateFPU.NeonSupport == InputFPU.NeonSupport &&
490         CandidateFPU.Restriction == ARM::FPURestriction::D16) {
491       return CandidateFPU.ID;
492     }
493   }
494 
495   // nothing found
496   return ARM::FK_INVALID;
497 }
498 
499 bool ARM::appendArchExtFeatures(StringRef CPU, ARM::ArchKind AK,
500                                 StringRef ArchExt,
501                                 std::vector<StringRef> &Features,
502                                 unsigned &ArgFPUID) {
503 
504   size_t StartingNumFeatures = Features.size();
505   const bool Negated = stripNegationPrefix(ArchExt);
506   uint64_t ID = parseArchExt(ArchExt);
507 
508   if (ID == AEK_INVALID)
509     return false;
510 
511   for (const auto &AE : ARCHExtNames) {
512     if (Negated) {
513       if ((AE.ID & ID) == ID && AE.NegFeature)
514         Features.push_back(AE.NegFeature);
515     } else {
516       if ((AE.ID & ID) == AE.ID && AE.Feature)
517         Features.push_back(AE.Feature);
518     }
519   }
520 
521   if (CPU == "")
522     CPU = "generic";
523 
524   if (ArchExt == "fp" || ArchExt == "fp.dp") {
525     unsigned FPUKind;
526     if (ArchExt == "fp.dp") {
527       if (Negated) {
528         Features.push_back("-fp64");
529         return true;
530       }
531       FPUKind = findDoublePrecisionFPU(getDefaultFPU(CPU, AK));
532     } else if (Negated) {
533       FPUKind = ARM::FK_NONE;
534     } else {
535       FPUKind = getDefaultFPU(CPU, AK);
536     }
537     ArgFPUID = FPUKind;
538     return ARM::getFPUFeatures(FPUKind, Features);
539   }
540   return StartingNumFeatures != Features.size();
541 }
542 
543 StringRef ARM::getDefaultCPU(StringRef Arch) {
544   ArchKind AK = parseArch(Arch);
545   if (AK == ArchKind::INVALID)
546     return StringRef();
547 
548   // Look for multiple AKs to find the default for pair AK+Name.
549   for (const auto &CPU : CPUNames) {
550     if (CPU.ArchID == AK && CPU.Default)
551       return CPU.getName();
552   }
553 
554   // If we can't find a default then target the architecture instead
555   return "generic";
556 }
557 
558 uint64_t ARM::parseHWDiv(StringRef HWDiv) {
559   StringRef Syn = getHWDivSynonym(HWDiv);
560   for (const auto &D : HWDivNames) {
561     if (Syn == D.getName())
562       return D.ID;
563   }
564   return AEK_INVALID;
565 }
566 
567 uint64_t ARM::parseArchExt(StringRef ArchExt) {
568   for (const auto &A : ARCHExtNames) {
569     if (ArchExt == A.getName())
570       return A.ID;
571   }
572   return AEK_INVALID;
573 }
574 
575 ARM::ArchKind ARM::parseCPUArch(StringRef CPU) {
576   for (const auto &C : CPUNames) {
577     if (CPU == C.getName())
578       return C.ArchID;
579   }
580   return ArchKind::INVALID;
581 }
582 
583 void ARM::fillValidCPUArchList(SmallVectorImpl<StringRef> &Values) {
584   for (const CpuNames<ArchKind> &Arch : CPUNames) {
585     if (Arch.ArchID != ArchKind::INVALID)
586       Values.push_back(Arch.getName());
587   }
588 }
589 
590 StringRef ARM::computeDefaultTargetABI(const Triple &TT, StringRef CPU) {
591   StringRef ArchName =
592       CPU.empty() ? TT.getArchName() : getArchName(parseCPUArch(CPU));
593 
594   if (TT.isOSBinFormatMachO()) {
595     if (TT.getEnvironment() == Triple::EABI ||
596         TT.getOS() == Triple::UnknownOS ||
597         parseArchProfile(ArchName) == ProfileKind::M)
598       return "aapcs";
599     if (TT.isWatchABI())
600       return "aapcs16";
601     return "apcs-gnu";
602   } else if (TT.isOSWindows())
603     // FIXME: this is invalid for WindowsCE.
604     return "aapcs";
605 
606   // Select the default based on the platform.
607   switch (TT.getEnvironment()) {
608   case Triple::Android:
609   case Triple::GNUEABI:
610   case Triple::GNUEABIHF:
611   case Triple::MuslEABI:
612   case Triple::MuslEABIHF:
613     return "aapcs-linux";
614   case Triple::EABIHF:
615   case Triple::EABI:
616     return "aapcs";
617   default:
618     if (TT.isOSNetBSD())
619       return "apcs-gnu";
620     if (TT.isOSOpenBSD())
621       return "aapcs-linux";
622     return "aapcs";
623   }
624 }
625