1 //===--- AArch64.cpp - AArch64 (not ARM) Helpers for Tools ------*- 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 #include "AArch64.h"
10 #include "clang/Driver/Driver.h"
11 #include "clang/Driver/DriverDiagnostic.h"
12 #include "clang/Driver/Options.h"
13 #include "llvm/Option/ArgList.h"
14 #include "llvm/Support/TargetParser.h"
15 #include "llvm/Support/Host.h"
16 
17 using namespace clang::driver;
18 using namespace clang::driver::tools;
19 using namespace clang;
20 using namespace llvm::opt;
21 
22 /// \returns true if the given triple can determine the default CPU type even
23 /// if -arch is not specified.
24 static bool isCPUDeterminedByTriple(const llvm::Triple &Triple) {
25   return Triple.isOSDarwin();
26 }
27 
28 /// getAArch64TargetCPU - Get the (LLVM) name of the AArch64 cpu we are
29 /// targeting. Set \p A to the Arg corresponding to the -mcpu argument if it is
30 /// provided, or to nullptr otherwise.
31 std::string aarch64::getAArch64TargetCPU(const ArgList &Args,
32                                          const llvm::Triple &Triple, Arg *&A) {
33   std::string CPU;
34   // If we have -mcpu, use that.
35   if ((A = Args.getLastArg(options::OPT_mcpu_EQ))) {
36     StringRef Mcpu = A->getValue();
37     CPU = Mcpu.split("+").first.lower();
38   }
39 
40   // Handle CPU name is 'native'.
41   if (CPU == "native")
42     return std::string(llvm::sys::getHostCPUName());
43   else if (CPU.size())
44     return CPU;
45 
46   // Make sure we pick the appropriate Apple CPU if -arch is used or when
47   // targetting a Darwin OS.
48   if (Args.getLastArg(options::OPT_arch) || Triple.isOSDarwin())
49     return Triple.getArch() == llvm::Triple::aarch64_32 ? "apple-s4"
50                                                         : "apple-a7";
51 
52   return "generic";
53 }
54 
55 // Decode AArch64 features from string like +[no]featureA+[no]featureB+...
56 static bool DecodeAArch64Features(const Driver &D, StringRef text,
57                                   std::vector<StringRef> &Features,
58                                   llvm::AArch64::ArchKind ArchKind) {
59   SmallVector<StringRef, 8> Split;
60   text.split(Split, StringRef("+"), -1, false);
61 
62   for (StringRef Feature : Split) {
63     StringRef FeatureName = llvm::AArch64::getArchExtFeature(Feature);
64     if (!FeatureName.empty())
65       Features.push_back(FeatureName);
66     else if (Feature == "neon" || Feature == "noneon")
67       D.Diag(clang::diag::err_drv_no_neon_modifier);
68     else
69       return false;
70 
71     // +sve implies +f32mm if the base architecture is v8.6A
72     // it isn't the case in general that sve implies both f64mm and f32mm
73     if ((ArchKind == llvm::AArch64::ArchKind::ARMV8_6A) && Feature == "sve")
74       Features.push_back("+f32mm");
75   }
76   return true;
77 }
78 
79 // Check if the CPU name and feature modifiers in -mcpu are legal. If yes,
80 // decode CPU and feature.
81 static bool DecodeAArch64Mcpu(const Driver &D, StringRef Mcpu, StringRef &CPU,
82                               std::vector<StringRef> &Features) {
83   std::pair<StringRef, StringRef> Split = Mcpu.split("+");
84   CPU = Split.first;
85   llvm::AArch64::ArchKind ArchKind = llvm::AArch64::ArchKind::ARMV8A;
86 
87   if (CPU == "native")
88     CPU = llvm::sys::getHostCPUName();
89 
90   if (CPU == "generic") {
91     Features.push_back("+neon");
92   } else {
93     ArchKind = llvm::AArch64::parseCPUArch(CPU);
94     if (!llvm::AArch64::getArchFeatures(ArchKind, Features))
95       return false;
96 
97     unsigned Extension = llvm::AArch64::getDefaultExtensions(CPU, ArchKind);
98     if (!llvm::AArch64::getExtensionFeatures(Extension, Features))
99       return false;
100    }
101 
102    if (Split.second.size() &&
103        !DecodeAArch64Features(D, Split.second, Features, ArchKind))
104      return false;
105 
106    return true;
107 }
108 
109 static bool
110 getAArch64ArchFeaturesFromMarch(const Driver &D, StringRef March,
111                                 const ArgList &Args,
112                                 std::vector<StringRef> &Features) {
113   std::string MarchLowerCase = March.lower();
114   std::pair<StringRef, StringRef> Split = StringRef(MarchLowerCase).split("+");
115 
116   llvm::AArch64::ArchKind ArchKind = llvm::AArch64::parseArch(Split.first);
117   if (ArchKind == llvm::AArch64::ArchKind::INVALID ||
118       !llvm::AArch64::getArchFeatures(ArchKind, Features) ||
119       (Split.second.size() &&
120        !DecodeAArch64Features(D, Split.second, Features, ArchKind)))
121     return false;
122 
123   return true;
124 }
125 
126 static bool
127 getAArch64ArchFeaturesFromMcpu(const Driver &D, StringRef Mcpu,
128                                const ArgList &Args,
129                                std::vector<StringRef> &Features) {
130   StringRef CPU;
131   std::string McpuLowerCase = Mcpu.lower();
132   if (!DecodeAArch64Mcpu(D, McpuLowerCase, CPU, Features))
133     return false;
134 
135   return true;
136 }
137 
138 static bool
139 getAArch64MicroArchFeaturesFromMtune(const Driver &D, StringRef Mtune,
140                                      const ArgList &Args,
141                                      std::vector<StringRef> &Features) {
142   std::string MtuneLowerCase = Mtune.lower();
143   // Check CPU name is valid
144   std::vector<StringRef> MtuneFeatures;
145   StringRef Tune;
146   if (!DecodeAArch64Mcpu(D, MtuneLowerCase, Tune, MtuneFeatures))
147     return false;
148 
149   // Handle CPU name is 'native'.
150   if (MtuneLowerCase == "native")
151     MtuneLowerCase = std::string(llvm::sys::getHostCPUName());
152   if (MtuneLowerCase == "cyclone" ||
153       StringRef(MtuneLowerCase).startswith("apple")) {
154     Features.push_back("+zcm");
155     Features.push_back("+zcz");
156   }
157   return true;
158 }
159 
160 static bool
161 getAArch64MicroArchFeaturesFromMcpu(const Driver &D, StringRef Mcpu,
162                                     const ArgList &Args,
163                                     std::vector<StringRef> &Features) {
164   StringRef CPU;
165   std::vector<StringRef> DecodedFeature;
166   std::string McpuLowerCase = Mcpu.lower();
167   if (!DecodeAArch64Mcpu(D, McpuLowerCase, CPU, DecodedFeature))
168     return false;
169 
170   return getAArch64MicroArchFeaturesFromMtune(D, CPU, Args, Features);
171 }
172 
173 void aarch64::getAArch64TargetFeatures(const Driver &D,
174                                        const llvm::Triple &Triple,
175                                        const ArgList &Args,
176                                        std::vector<StringRef> &Features) {
177   Arg *A;
178   bool success = true;
179   // Enable NEON by default.
180   Features.push_back("+neon");
181   if ((A = Args.getLastArg(options::OPT_march_EQ)))
182     success = getAArch64ArchFeaturesFromMarch(D, A->getValue(), Args, Features);
183   else if ((A = Args.getLastArg(options::OPT_mcpu_EQ)))
184     success = getAArch64ArchFeaturesFromMcpu(D, A->getValue(), Args, Features);
185   else if (Args.hasArg(options::OPT_arch) || isCPUDeterminedByTriple(Triple))
186     success = getAArch64ArchFeaturesFromMcpu(
187         D, getAArch64TargetCPU(Args, Triple, A), Args, Features);
188 
189   if (success && (A = Args.getLastArg(clang::driver::options::OPT_mtune_EQ)))
190     success =
191         getAArch64MicroArchFeaturesFromMtune(D, A->getValue(), Args, Features);
192   else if (success && (A = Args.getLastArg(options::OPT_mcpu_EQ)))
193     success =
194         getAArch64MicroArchFeaturesFromMcpu(D, A->getValue(), Args, Features);
195   else if (success &&
196            (Args.hasArg(options::OPT_arch) || isCPUDeterminedByTriple(Triple)))
197     success = getAArch64MicroArchFeaturesFromMcpu(
198         D, getAArch64TargetCPU(Args, Triple, A), Args, Features);
199 
200   if (!success)
201     D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
202 
203   if (Args.getLastArg(options::OPT_mgeneral_regs_only)) {
204     Features.push_back("-fp-armv8");
205     Features.push_back("-crypto");
206     Features.push_back("-neon");
207   }
208 
209   if (Arg *A = Args.getLastArg(options::OPT_mtp_mode_EQ)) {
210     StringRef Mtp = A->getValue();
211     if (Mtp == "el3")
212       Features.push_back("+tpidr-el3");
213     else if (Mtp == "el2")
214       Features.push_back("+tpidr-el2");
215     else if (Mtp == "el1")
216       Features.push_back("+tpidr-el1");
217     else if (Mtp != "el0")
218       D.Diag(diag::err_drv_invalid_mtp) << A->getAsString(Args);
219   }
220 
221   // Enable/disable straight line speculation hardening.
222   if (Arg *A = Args.getLastArg(options::OPT_mharden_sls_EQ)) {
223     StringRef Scope = A->getValue();
224     bool EnableRetBr = false;
225     bool EnableBlr = false;
226     if (Scope != "none" && Scope != "all") {
227       SmallVector<StringRef, 4> Opts;
228       Scope.split(Opts, ",");
229       for (auto Opt : Opts) {
230         Opt = Opt.trim();
231         if (Opt == "retbr") {
232           EnableRetBr = true;
233           continue;
234         }
235         if (Opt == "blr") {
236           EnableBlr = true;
237           continue;
238         }
239         D.Diag(diag::err_invalid_sls_hardening)
240             << Scope << A->getAsString(Args);
241         break;
242       }
243     } else if (Scope == "all") {
244       EnableRetBr = true;
245       EnableBlr = true;
246     }
247 
248     if (EnableRetBr)
249       Features.push_back("+harden-sls-retbr");
250     if (EnableBlr)
251       Features.push_back("+harden-sls-blr");
252   }
253 
254   // En/disable crc
255   if (Arg *A = Args.getLastArg(options::OPT_mcrc, options::OPT_mnocrc)) {
256     if (A->getOption().matches(options::OPT_mcrc))
257       Features.push_back("+crc");
258     else
259       Features.push_back("-crc");
260   }
261 
262   // Handle (arch-dependent) fp16fml/fullfp16 relationship.
263   // FIXME: this fp16fml option handling will be reimplemented after the
264   // TargetParser rewrite.
265   const auto ItRNoFullFP16 = std::find(Features.rbegin(), Features.rend(), "-fullfp16");
266   const auto ItRFP16FML = std::find(Features.rbegin(), Features.rend(), "+fp16fml");
267   if (llvm::is_contained(Features, "+v8.4a")) {
268     const auto ItRFullFP16  = std::find(Features.rbegin(), Features.rend(), "+fullfp16");
269     if (ItRFullFP16 < ItRNoFullFP16 && ItRFullFP16 < ItRFP16FML) {
270       // Only entangled feature that can be to the right of this +fullfp16 is -fp16fml.
271       // Only append the +fp16fml if there is no -fp16fml after the +fullfp16.
272       if (std::find(Features.rbegin(), ItRFullFP16, "-fp16fml") == ItRFullFP16)
273         Features.push_back("+fp16fml");
274     }
275     else
276       goto fp16_fml_fallthrough;
277   } else {
278 fp16_fml_fallthrough:
279     // In both of these cases, putting the 'other' feature on the end of the vector will
280     // result in the same effect as placing it immediately after the current feature.
281     if (ItRNoFullFP16 < ItRFP16FML)
282       Features.push_back("-fp16fml");
283     else if (ItRNoFullFP16 > ItRFP16FML)
284       Features.push_back("+fullfp16");
285   }
286 
287   // FIXME: this needs reimplementation too after the TargetParser rewrite
288   //
289   // Context sensitive meaning of Crypto:
290   // 1) For Arch >= ARMv8.4a:  crypto = sm4 + sha3 + sha2 + aes
291   // 2) For Arch <= ARMv8.3a:  crypto = sha2 + aes
292   const auto ItBegin = Features.begin();
293   const auto ItEnd = Features.end();
294   const auto ItRBegin = Features.rbegin();
295   const auto ItREnd = Features.rend();
296   const auto ItRCrypto = std::find(ItRBegin, ItREnd, "+crypto");
297   const auto ItRNoCrypto = std::find(ItRBegin, ItREnd, "-crypto");
298   const auto HasCrypto  = ItRCrypto != ItREnd;
299   const auto HasNoCrypto = ItRNoCrypto != ItREnd;
300   const ptrdiff_t PosCrypto = ItRCrypto - ItRBegin;
301   const ptrdiff_t PosNoCrypto = ItRNoCrypto - ItRBegin;
302 
303   bool NoCrypto = false;
304   if (HasCrypto && HasNoCrypto) {
305     if (PosNoCrypto < PosCrypto)
306       NoCrypto = true;
307   }
308 
309   if (std::find(ItBegin, ItEnd, "+v8.4a") != ItEnd) {
310     if (HasCrypto && !NoCrypto) {
311       // Check if we have NOT disabled an algorithm with something like:
312       //   +crypto, -algorithm
313       // And if "-algorithm" does not occur, we enable that crypto algorithm.
314       const bool HasSM4  = (std::find(ItBegin, ItEnd, "-sm4") == ItEnd);
315       const bool HasSHA3 = (std::find(ItBegin, ItEnd, "-sha3") == ItEnd);
316       const bool HasSHA2 = (std::find(ItBegin, ItEnd, "-sha2") == ItEnd);
317       const bool HasAES  = (std::find(ItBegin, ItEnd, "-aes") == ItEnd);
318       if (HasSM4)
319         Features.push_back("+sm4");
320       if (HasSHA3)
321         Features.push_back("+sha3");
322       if (HasSHA2)
323         Features.push_back("+sha2");
324       if (HasAES)
325         Features.push_back("+aes");
326     } else if (HasNoCrypto) {
327       // Check if we have NOT enabled a crypto algorithm with something like:
328       //   -crypto, +algorithm
329       // And if "+algorithm" does not occur, we disable that crypto algorithm.
330       const bool HasSM4  = (std::find(ItBegin, ItEnd, "+sm4") != ItEnd);
331       const bool HasSHA3 = (std::find(ItBegin, ItEnd, "+sha3") != ItEnd);
332       const bool HasSHA2 = (std::find(ItBegin, ItEnd, "+sha2") != ItEnd);
333       const bool HasAES  = (std::find(ItBegin, ItEnd, "+aes") != ItEnd);
334       if (!HasSM4)
335         Features.push_back("-sm4");
336       if (!HasSHA3)
337         Features.push_back("-sha3");
338       if (!HasSHA2)
339         Features.push_back("-sha2");
340       if (!HasAES)
341         Features.push_back("-aes");
342     }
343   } else {
344     if (HasCrypto && !NoCrypto) {
345       const bool HasSHA2 = (std::find(ItBegin, ItEnd, "-sha2") == ItEnd);
346       const bool HasAES = (std::find(ItBegin, ItEnd, "-aes") == ItEnd);
347       if (HasSHA2)
348         Features.push_back("+sha2");
349       if (HasAES)
350         Features.push_back("+aes");
351     } else if (HasNoCrypto) {
352       const bool HasSHA2 = (std::find(ItBegin, ItEnd, "+sha2") != ItEnd);
353       const bool HasAES  = (std::find(ItBegin, ItEnd, "+aes") != ItEnd);
354       const bool HasV82a = (std::find(ItBegin, ItEnd, "+v8.2a") != ItEnd);
355       const bool HasV83a = (std::find(ItBegin, ItEnd, "+v8.3a") != ItEnd);
356       const bool HasV84a = (std::find(ItBegin, ItEnd, "+v8.4a") != ItEnd);
357       if (!HasSHA2)
358         Features.push_back("-sha2");
359       if (!HasAES)
360         Features.push_back("-aes");
361       if (HasV82a || HasV83a || HasV84a) {
362         Features.push_back("-sm4");
363         Features.push_back("-sha3");
364       }
365     }
366   }
367 
368   auto V8_6Pos = llvm::find(Features, "+v8.6a");
369   if (V8_6Pos != std::end(Features))
370     V8_6Pos = Features.insert(std::next(V8_6Pos), {"+i8mm", "+bf16"});
371 
372   if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,
373                                options::OPT_munaligned_access)) {
374     if (A->getOption().matches(options::OPT_mno_unaligned_access))
375       Features.push_back("+strict-align");
376   } else if (Triple.isOSOpenBSD())
377     Features.push_back("+strict-align");
378 
379   if (Args.hasArg(options::OPT_ffixed_x1))
380     Features.push_back("+reserve-x1");
381 
382   if (Args.hasArg(options::OPT_ffixed_x2))
383     Features.push_back("+reserve-x2");
384 
385   if (Args.hasArg(options::OPT_ffixed_x3))
386     Features.push_back("+reserve-x3");
387 
388   if (Args.hasArg(options::OPT_ffixed_x4))
389     Features.push_back("+reserve-x4");
390 
391   if (Args.hasArg(options::OPT_ffixed_x5))
392     Features.push_back("+reserve-x5");
393 
394   if (Args.hasArg(options::OPT_ffixed_x6))
395     Features.push_back("+reserve-x6");
396 
397   if (Args.hasArg(options::OPT_ffixed_x7))
398     Features.push_back("+reserve-x7");
399 
400   if (Args.hasArg(options::OPT_ffixed_x9))
401     Features.push_back("+reserve-x9");
402 
403   if (Args.hasArg(options::OPT_ffixed_x10))
404     Features.push_back("+reserve-x10");
405 
406   if (Args.hasArg(options::OPT_ffixed_x11))
407     Features.push_back("+reserve-x11");
408 
409   if (Args.hasArg(options::OPT_ffixed_x12))
410     Features.push_back("+reserve-x12");
411 
412   if (Args.hasArg(options::OPT_ffixed_x13))
413     Features.push_back("+reserve-x13");
414 
415   if (Args.hasArg(options::OPT_ffixed_x14))
416     Features.push_back("+reserve-x14");
417 
418   if (Args.hasArg(options::OPT_ffixed_x15))
419     Features.push_back("+reserve-x15");
420 
421   if (Args.hasArg(options::OPT_ffixed_x18))
422     Features.push_back("+reserve-x18");
423 
424   if (Args.hasArg(options::OPT_ffixed_x20))
425     Features.push_back("+reserve-x20");
426 
427   if (Args.hasArg(options::OPT_ffixed_x21))
428     Features.push_back("+reserve-x21");
429 
430   if (Args.hasArg(options::OPT_ffixed_x22))
431     Features.push_back("+reserve-x22");
432 
433   if (Args.hasArg(options::OPT_ffixed_x23))
434     Features.push_back("+reserve-x23");
435 
436   if (Args.hasArg(options::OPT_ffixed_x24))
437     Features.push_back("+reserve-x24");
438 
439   if (Args.hasArg(options::OPT_ffixed_x25))
440     Features.push_back("+reserve-x25");
441 
442   if (Args.hasArg(options::OPT_ffixed_x26))
443     Features.push_back("+reserve-x26");
444 
445   if (Args.hasArg(options::OPT_ffixed_x27))
446     Features.push_back("+reserve-x27");
447 
448   if (Args.hasArg(options::OPT_ffixed_x28))
449     Features.push_back("+reserve-x28");
450 
451   if (Args.hasArg(options::OPT_ffixed_x30))
452     Features.push_back("+reserve-x30");
453 
454   if (Args.hasArg(options::OPT_fcall_saved_x8))
455     Features.push_back("+call-saved-x8");
456 
457   if (Args.hasArg(options::OPT_fcall_saved_x9))
458     Features.push_back("+call-saved-x9");
459 
460   if (Args.hasArg(options::OPT_fcall_saved_x10))
461     Features.push_back("+call-saved-x10");
462 
463   if (Args.hasArg(options::OPT_fcall_saved_x11))
464     Features.push_back("+call-saved-x11");
465 
466   if (Args.hasArg(options::OPT_fcall_saved_x12))
467     Features.push_back("+call-saved-x12");
468 
469   if (Args.hasArg(options::OPT_fcall_saved_x13))
470     Features.push_back("+call-saved-x13");
471 
472   if (Args.hasArg(options::OPT_fcall_saved_x14))
473     Features.push_back("+call-saved-x14");
474 
475   if (Args.hasArg(options::OPT_fcall_saved_x15))
476     Features.push_back("+call-saved-x15");
477 
478   if (Args.hasArg(options::OPT_fcall_saved_x18))
479     Features.push_back("+call-saved-x18");
480 
481   if (Args.hasArg(options::OPT_mno_neg_immediates))
482     Features.push_back("+no-neg-immediates");
483 }
484