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