1 //===-- Host.cpp - Implement OS Host Concept --------------------*- 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 the operating system Host concept.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Support/Host.h"
14 #include "llvm/ADT/SmallSet.h"
15 #include "llvm/ADT/SmallVector.h"
16 #include "llvm/ADT/StringMap.h"
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/ADT/StringSwitch.h"
19 #include "llvm/ADT/Triple.h"
20 #include "llvm/Config/llvm-config.h"
21 #include "llvm/Support/BCD.h"
22 #include "llvm/Support/Debug.h"
23 #include "llvm/Support/FileSystem.h"
24 #include "llvm/Support/MemoryBuffer.h"
25 #include "llvm/Support/X86TargetParser.h"
26 #include "llvm/Support/raw_ostream.h"
27 #include <assert.h>
28 #include <string.h>
29 
30 // Include the platform-specific parts of this class.
31 #ifdef LLVM_ON_UNIX
32 #include "Unix/Host.inc"
33 #include <sched.h>
34 #endif
35 #ifdef _WIN32
36 #include "Windows/Host.inc"
37 #endif
38 #ifdef _MSC_VER
39 #include <intrin.h>
40 #endif
41 #if defined(__APPLE__) && (!defined(__x86_64__))
42 #include <mach/host_info.h>
43 #include <mach/mach.h>
44 #include <mach/mach_host.h>
45 #include <mach/machine.h>
46 #endif
47 #ifdef _AIX
48 #include <sys/systemcfg.h>
49 #endif
50 
51 #define DEBUG_TYPE "host-detection"
52 
53 //===----------------------------------------------------------------------===//
54 //
55 //  Implementations of the CPU detection routines
56 //
57 //===----------------------------------------------------------------------===//
58 
59 using namespace llvm;
60 
61 static std::unique_ptr<llvm::MemoryBuffer>
62     LLVM_ATTRIBUTE_UNUSED getProcCpuinfoContent() {
63   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> Text =
64       llvm::MemoryBuffer::getFileAsStream("/proc/cpuinfo");
65   if (std::error_code EC = Text.getError()) {
66     llvm::errs() << "Can't read "
67                  << "/proc/cpuinfo: " << EC.message() << "\n";
68     return nullptr;
69   }
70   return std::move(*Text);
71 }
72 
73 StringRef sys::detail::getHostCPUNameForPowerPC(StringRef ProcCpuinfoContent) {
74   // Access to the Processor Version Register (PVR) on PowerPC is privileged,
75   // and so we must use an operating-system interface to determine the current
76   // processor type. On Linux, this is exposed through the /proc/cpuinfo file.
77   const char *generic = "generic";
78 
79   // The cpu line is second (after the 'processor: 0' line), so if this
80   // buffer is too small then something has changed (or is wrong).
81   StringRef::const_iterator CPUInfoStart = ProcCpuinfoContent.begin();
82   StringRef::const_iterator CPUInfoEnd = ProcCpuinfoContent.end();
83 
84   StringRef::const_iterator CIP = CPUInfoStart;
85 
86   StringRef::const_iterator CPUStart = nullptr;
87   size_t CPULen = 0;
88 
89   // We need to find the first line which starts with cpu, spaces, and a colon.
90   // After the colon, there may be some additional spaces and then the cpu type.
91   while (CIP < CPUInfoEnd && CPUStart == nullptr) {
92     if (CIP < CPUInfoEnd && *CIP == '\n')
93       ++CIP;
94 
95     if (CIP < CPUInfoEnd && *CIP == 'c') {
96       ++CIP;
97       if (CIP < CPUInfoEnd && *CIP == 'p') {
98         ++CIP;
99         if (CIP < CPUInfoEnd && *CIP == 'u') {
100           ++CIP;
101           while (CIP < CPUInfoEnd && (*CIP == ' ' || *CIP == '\t'))
102             ++CIP;
103 
104           if (CIP < CPUInfoEnd && *CIP == ':') {
105             ++CIP;
106             while (CIP < CPUInfoEnd && (*CIP == ' ' || *CIP == '\t'))
107               ++CIP;
108 
109             if (CIP < CPUInfoEnd) {
110               CPUStart = CIP;
111               while (CIP < CPUInfoEnd && (*CIP != ' ' && *CIP != '\t' &&
112                                           *CIP != ',' && *CIP != '\n'))
113                 ++CIP;
114               CPULen = CIP - CPUStart;
115             }
116           }
117         }
118       }
119     }
120 
121     if (CPUStart == nullptr)
122       while (CIP < CPUInfoEnd && *CIP != '\n')
123         ++CIP;
124   }
125 
126   if (CPUStart == nullptr)
127     return generic;
128 
129   return StringSwitch<const char *>(StringRef(CPUStart, CPULen))
130       .Case("604e", "604e")
131       .Case("604", "604")
132       .Case("7400", "7400")
133       .Case("7410", "7400")
134       .Case("7447", "7400")
135       .Case("7455", "7450")
136       .Case("G4", "g4")
137       .Case("POWER4", "970")
138       .Case("PPC970FX", "970")
139       .Case("PPC970MP", "970")
140       .Case("G5", "g5")
141       .Case("POWER5", "g5")
142       .Case("A2", "a2")
143       .Case("POWER6", "pwr6")
144       .Case("POWER7", "pwr7")
145       .Case("POWER8", "pwr8")
146       .Case("POWER8E", "pwr8")
147       .Case("POWER8NVL", "pwr8")
148       .Case("POWER9", "pwr9")
149       .Case("POWER10", "pwr10")
150       // FIXME: If we get a simulator or machine with the capabilities of
151       // mcpu=future, we should revisit this and add the name reported by the
152       // simulator/machine.
153       .Default(generic);
154 }
155 
156 StringRef sys::detail::getHostCPUNameForARM(StringRef ProcCpuinfoContent) {
157   // The cpuid register on arm is not accessible from user space. On Linux,
158   // it is exposed through the /proc/cpuinfo file.
159 
160   // Read 32 lines from /proc/cpuinfo, which should contain the CPU part line
161   // in all cases.
162   SmallVector<StringRef, 32> Lines;
163   ProcCpuinfoContent.split(Lines, "\n");
164 
165   // Look for the CPU implementer line.
166   StringRef Implementer;
167   StringRef Hardware;
168   StringRef Part;
169   for (unsigned I = 0, E = Lines.size(); I != E; ++I) {
170     if (Lines[I].startswith("CPU implementer"))
171       Implementer = Lines[I].substr(15).ltrim("\t :");
172     if (Lines[I].startswith("Hardware"))
173       Hardware = Lines[I].substr(8).ltrim("\t :");
174     if (Lines[I].startswith("CPU part"))
175       Part = Lines[I].substr(8).ltrim("\t :");
176   }
177 
178   if (Implementer == "0x41") { // ARM Ltd.
179     // MSM8992/8994 may give cpu part for the core that the kernel is running on,
180     // which is undeterministic and wrong. Always return cortex-a53 for these SoC.
181     if (Hardware.endswith("MSM8994") || Hardware.endswith("MSM8996"))
182       return "cortex-a53";
183 
184 
185     // The CPU part is a 3 digit hexadecimal number with a 0x prefix. The
186     // values correspond to the "Part number" in the CP15/c0 register. The
187     // contents are specified in the various processor manuals.
188     // This corresponds to the Main ID Register in Technical Reference Manuals.
189     // and is used in programs like sys-utils
190     return StringSwitch<const char *>(Part)
191         .Case("0x926", "arm926ej-s")
192         .Case("0xb02", "mpcore")
193         .Case("0xb36", "arm1136j-s")
194         .Case("0xb56", "arm1156t2-s")
195         .Case("0xb76", "arm1176jz-s")
196         .Case("0xc08", "cortex-a8")
197         .Case("0xc09", "cortex-a9")
198         .Case("0xc0f", "cortex-a15")
199         .Case("0xc20", "cortex-m0")
200         .Case("0xc23", "cortex-m3")
201         .Case("0xc24", "cortex-m4")
202         .Case("0xd22", "cortex-m55")
203         .Case("0xd02", "cortex-a34")
204         .Case("0xd04", "cortex-a35")
205         .Case("0xd03", "cortex-a53")
206         .Case("0xd07", "cortex-a57")
207         .Case("0xd08", "cortex-a72")
208         .Case("0xd09", "cortex-a73")
209         .Case("0xd0a", "cortex-a75")
210         .Case("0xd0b", "cortex-a76")
211         .Case("0xd0d", "cortex-a77")
212         .Case("0xd41", "cortex-a78")
213         .Case("0xd44", "cortex-x1")
214         .Case("0xd0c", "neoverse-n1")
215         .Case("0xd49", "neoverse-n2")
216         .Case("0xd40", "neoverse-v1")
217         .Default("generic");
218   }
219 
220   if (Implementer == "0x42" || Implementer == "0x43") { // Broadcom | Cavium.
221     return StringSwitch<const char *>(Part)
222       .Case("0x516", "thunderx2t99")
223       .Case("0x0516", "thunderx2t99")
224       .Case("0xaf", "thunderx2t99")
225       .Case("0x0af", "thunderx2t99")
226       .Case("0xa1", "thunderxt88")
227       .Case("0x0a1", "thunderxt88")
228       .Default("generic");
229   }
230 
231   if (Implementer == "0x46") { // Fujitsu Ltd.
232     return StringSwitch<const char *>(Part)
233       .Case("0x001", "a64fx")
234       .Default("generic");
235   }
236 
237   if (Implementer == "0x4e") { // NVIDIA Corporation
238     return StringSwitch<const char *>(Part)
239         .Case("0x004", "carmel")
240         .Default("generic");
241   }
242 
243   if (Implementer == "0x48") // HiSilicon Technologies, Inc.
244     // The CPU part is a 3 digit hexadecimal number with a 0x prefix. The
245     // values correspond to the "Part number" in the CP15/c0 register. The
246     // contents are specified in the various processor manuals.
247     return StringSwitch<const char *>(Part)
248       .Case("0xd01", "tsv110")
249       .Default("generic");
250 
251   if (Implementer == "0x51") // Qualcomm Technologies, Inc.
252     // The CPU part is a 3 digit hexadecimal number with a 0x prefix. The
253     // values correspond to the "Part number" in the CP15/c0 register. The
254     // contents are specified in the various processor manuals.
255     return StringSwitch<const char *>(Part)
256         .Case("0x06f", "krait") // APQ8064
257         .Case("0x201", "kryo")
258         .Case("0x205", "kryo")
259         .Case("0x211", "kryo")
260         .Case("0x800", "cortex-a73") // Kryo 2xx Gold
261         .Case("0x801", "cortex-a73") // Kryo 2xx Silver
262         .Case("0x802", "cortex-a75") // Kryo 3xx Gold
263         .Case("0x803", "cortex-a75") // Kryo 3xx Silver
264         .Case("0x804", "cortex-a76") // Kryo 4xx Gold
265         .Case("0x805", "cortex-a76") // Kryo 4xx/5xx Silver
266         .Case("0xc00", "falkor")
267         .Case("0xc01", "saphira")
268         .Default("generic");
269   if (Implementer == "0x53") { // Samsung Electronics Co., Ltd.
270     // The Exynos chips have a convoluted ID scheme that doesn't seem to follow
271     // any predictive pattern across variants and parts.
272     unsigned Variant = 0, Part = 0;
273 
274     // Look for the CPU variant line, whose value is a 1 digit hexadecimal
275     // number, corresponding to the Variant bits in the CP15/C0 register.
276     for (auto I : Lines)
277       if (I.consume_front("CPU variant"))
278         I.ltrim("\t :").getAsInteger(0, Variant);
279 
280     // Look for the CPU part line, whose value is a 3 digit hexadecimal
281     // number, corresponding to the PartNum bits in the CP15/C0 register.
282     for (auto I : Lines)
283       if (I.consume_front("CPU part"))
284         I.ltrim("\t :").getAsInteger(0, Part);
285 
286     unsigned Exynos = (Variant << 12) | Part;
287     switch (Exynos) {
288     default:
289       // Default by falling through to Exynos M3.
290       LLVM_FALLTHROUGH;
291     case 0x1002:
292       return "exynos-m3";
293     case 0x1003:
294       return "exynos-m4";
295     }
296   }
297 
298   return "generic";
299 }
300 
301 namespace {
302 StringRef getCPUNameFromS390Model(unsigned int Id, bool HaveVectorSupport) {
303   switch (Id) {
304     case 2064:  // z900 not supported by LLVM
305     case 2066:
306     case 2084:  // z990 not supported by LLVM
307     case 2086:
308     case 2094:  // z9-109 not supported by LLVM
309     case 2096:
310       return "generic";
311     case 2097:
312     case 2098:
313       return "z10";
314     case 2817:
315     case 2818:
316       return "z196";
317     case 2827:
318     case 2828:
319       return "zEC12";
320     case 2964:
321     case 2965:
322       return HaveVectorSupport? "z13" : "zEC12";
323     case 3906:
324     case 3907:
325       return HaveVectorSupport? "z14" : "zEC12";
326     case 8561:
327     case 8562:
328       return HaveVectorSupport? "z15" : "zEC12";
329     case 3931:
330     case 3932:
331     default:
332       return HaveVectorSupport? "arch14" : "zEC12";
333   }
334 }
335 } // end anonymous namespace
336 
337 StringRef sys::detail::getHostCPUNameForS390x(StringRef ProcCpuinfoContent) {
338   // STIDP is a privileged operation, so use /proc/cpuinfo instead.
339 
340   // The "processor 0:" line comes after a fair amount of other information,
341   // including a cache breakdown, but this should be plenty.
342   SmallVector<StringRef, 32> Lines;
343   ProcCpuinfoContent.split(Lines, "\n");
344 
345   // Look for the CPU features.
346   SmallVector<StringRef, 32> CPUFeatures;
347   for (unsigned I = 0, E = Lines.size(); I != E; ++I)
348     if (Lines[I].startswith("features")) {
349       size_t Pos = Lines[I].find(':');
350       if (Pos != StringRef::npos) {
351         Lines[I].drop_front(Pos + 1).split(CPUFeatures, ' ');
352         break;
353       }
354     }
355 
356   // We need to check for the presence of vector support independently of
357   // the machine type, since we may only use the vector register set when
358   // supported by the kernel (and hypervisor).
359   bool HaveVectorSupport = false;
360   for (unsigned I = 0, E = CPUFeatures.size(); I != E; ++I) {
361     if (CPUFeatures[I] == "vx")
362       HaveVectorSupport = true;
363   }
364 
365   // Now check the processor machine type.
366   for (unsigned I = 0, E = Lines.size(); I != E; ++I) {
367     if (Lines[I].startswith("processor ")) {
368       size_t Pos = Lines[I].find("machine = ");
369       if (Pos != StringRef::npos) {
370         Pos += sizeof("machine = ") - 1;
371         unsigned int Id;
372         if (!Lines[I].drop_front(Pos).getAsInteger(10, Id))
373           return getCPUNameFromS390Model(Id, HaveVectorSupport);
374       }
375       break;
376     }
377   }
378 
379   return "generic";
380 }
381 
382 StringRef sys::detail::getHostCPUNameForBPF() {
383 #if !defined(__linux__) || !defined(__x86_64__)
384   return "generic";
385 #else
386   uint8_t v3_insns[40] __attribute__ ((aligned (8))) =
387       /* BPF_MOV64_IMM(BPF_REG_0, 0) */
388     { 0xb7, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
389       /* BPF_MOV64_IMM(BPF_REG_2, 1) */
390       0xb7, 0x2, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0,
391       /* BPF_JMP32_REG(BPF_JLT, BPF_REG_0, BPF_REG_2, 1) */
392       0xae, 0x20, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0,
393       /* BPF_MOV64_IMM(BPF_REG_0, 1) */
394       0xb7, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0,
395       /* BPF_EXIT_INSN() */
396       0x95, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 };
397 
398   uint8_t v2_insns[40] __attribute__ ((aligned (8))) =
399       /* BPF_MOV64_IMM(BPF_REG_0, 0) */
400     { 0xb7, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
401       /* BPF_MOV64_IMM(BPF_REG_2, 1) */
402       0xb7, 0x2, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0,
403       /* BPF_JMP_REG(BPF_JLT, BPF_REG_0, BPF_REG_2, 1) */
404       0xad, 0x20, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0,
405       /* BPF_MOV64_IMM(BPF_REG_0, 1) */
406       0xb7, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0,
407       /* BPF_EXIT_INSN() */
408       0x95, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0 };
409 
410   struct bpf_prog_load_attr {
411     uint32_t prog_type;
412     uint32_t insn_cnt;
413     uint64_t insns;
414     uint64_t license;
415     uint32_t log_level;
416     uint32_t log_size;
417     uint64_t log_buf;
418     uint32_t kern_version;
419     uint32_t prog_flags;
420   } attr = {};
421   attr.prog_type = 1; /* BPF_PROG_TYPE_SOCKET_FILTER */
422   attr.insn_cnt = 5;
423   attr.insns = (uint64_t)v3_insns;
424   attr.license = (uint64_t)"DUMMY";
425 
426   int fd = syscall(321 /* __NR_bpf */, 5 /* BPF_PROG_LOAD */, &attr,
427                    sizeof(attr));
428   if (fd >= 0) {
429     close(fd);
430     return "v3";
431   }
432 
433   /* Clear the whole attr in case its content changed by syscall. */
434   memset(&attr, 0, sizeof(attr));
435   attr.prog_type = 1; /* BPF_PROG_TYPE_SOCKET_FILTER */
436   attr.insn_cnt = 5;
437   attr.insns = (uint64_t)v2_insns;
438   attr.license = (uint64_t)"DUMMY";
439   fd = syscall(321 /* __NR_bpf */, 5 /* BPF_PROG_LOAD */, &attr, sizeof(attr));
440   if (fd >= 0) {
441     close(fd);
442     return "v2";
443   }
444   return "v1";
445 #endif
446 }
447 
448 #if defined(__i386__) || defined(_M_IX86) || \
449     defined(__x86_64__) || defined(_M_X64)
450 
451 // The check below for i386 was copied from clang's cpuid.h (__get_cpuid_max).
452 // Check motivated by bug reports for OpenSSL crashing on CPUs without CPUID
453 // support. Consequently, for i386, the presence of CPUID is checked first
454 // via the corresponding eflags bit.
455 // Removal of cpuid.h header motivated by PR30384
456 // Header cpuid.h and method __get_cpuid_max are not used in llvm, clang, openmp
457 // or test-suite, but are used in external projects e.g. libstdcxx
458 static bool isCpuIdSupported() {
459 #if defined(__GNUC__) || defined(__clang__)
460 #if defined(__i386__)
461   int __cpuid_supported;
462   __asm__("  pushfl\n"
463           "  popl   %%eax\n"
464           "  movl   %%eax,%%ecx\n"
465           "  xorl   $0x00200000,%%eax\n"
466           "  pushl  %%eax\n"
467           "  popfl\n"
468           "  pushfl\n"
469           "  popl   %%eax\n"
470           "  movl   $0,%0\n"
471           "  cmpl   %%eax,%%ecx\n"
472           "  je     1f\n"
473           "  movl   $1,%0\n"
474           "1:"
475           : "=r"(__cpuid_supported)
476           :
477           : "eax", "ecx");
478   if (!__cpuid_supported)
479     return false;
480 #endif
481   return true;
482 #endif
483   return true;
484 }
485 
486 /// getX86CpuIDAndInfo - Execute the specified cpuid and return the 4 values in
487 /// the specified arguments.  If we can't run cpuid on the host, return true.
488 static bool getX86CpuIDAndInfo(unsigned value, unsigned *rEAX, unsigned *rEBX,
489                                unsigned *rECX, unsigned *rEDX) {
490 #if defined(__GNUC__) || defined(__clang__)
491 #if defined(__x86_64__)
492   // gcc doesn't know cpuid would clobber ebx/rbx. Preserve it manually.
493   // FIXME: should we save this for Clang?
494   __asm__("movq\t%%rbx, %%rsi\n\t"
495           "cpuid\n\t"
496           "xchgq\t%%rbx, %%rsi\n\t"
497           : "=a"(*rEAX), "=S"(*rEBX), "=c"(*rECX), "=d"(*rEDX)
498           : "a"(value));
499   return false;
500 #elif defined(__i386__)
501   __asm__("movl\t%%ebx, %%esi\n\t"
502           "cpuid\n\t"
503           "xchgl\t%%ebx, %%esi\n\t"
504           : "=a"(*rEAX), "=S"(*rEBX), "=c"(*rECX), "=d"(*rEDX)
505           : "a"(value));
506   return false;
507 #else
508   return true;
509 #endif
510 #elif defined(_MSC_VER)
511   // The MSVC intrinsic is portable across x86 and x64.
512   int registers[4];
513   __cpuid(registers, value);
514   *rEAX = registers[0];
515   *rEBX = registers[1];
516   *rECX = registers[2];
517   *rEDX = registers[3];
518   return false;
519 #else
520   return true;
521 #endif
522 }
523 
524 namespace llvm {
525 namespace sys {
526 namespace detail {
527 namespace x86 {
528 
529 VendorSignatures getVendorSignature(unsigned *MaxLeaf) {
530   unsigned EAX = 0, EBX = 0, ECX = 0, EDX = 0;
531   if (MaxLeaf == nullptr)
532     MaxLeaf = &EAX;
533   else
534     *MaxLeaf = 0;
535 
536   if (!isCpuIdSupported())
537     return VendorSignatures::UNKNOWN;
538 
539   if (getX86CpuIDAndInfo(0, MaxLeaf, &EBX, &ECX, &EDX) || *MaxLeaf < 1)
540     return VendorSignatures::UNKNOWN;
541 
542   // "Genu ineI ntel"
543   if (EBX == 0x756e6547 && EDX == 0x49656e69 && ECX == 0x6c65746e)
544     return VendorSignatures::GENUINE_INTEL;
545 
546   // "Auth enti cAMD"
547   if (EBX == 0x68747541 && EDX == 0x69746e65 && ECX == 0x444d4163)
548     return VendorSignatures::AUTHENTIC_AMD;
549 
550   return VendorSignatures::UNKNOWN;
551 }
552 
553 } // namespace x86
554 } // namespace detail
555 } // namespace sys
556 } // namespace llvm
557 
558 using namespace llvm::sys::detail::x86;
559 
560 /// getX86CpuIDAndInfoEx - Execute the specified cpuid with subleaf and return
561 /// the 4 values in the specified arguments.  If we can't run cpuid on the host,
562 /// return true.
563 static bool getX86CpuIDAndInfoEx(unsigned value, unsigned subleaf,
564                                  unsigned *rEAX, unsigned *rEBX, unsigned *rECX,
565                                  unsigned *rEDX) {
566 #if defined(__GNUC__) || defined(__clang__)
567 #if defined(__x86_64__)
568   // gcc doesn't know cpuid would clobber ebx/rbx. Preserve it manually.
569   // FIXME: should we save this for Clang?
570   __asm__("movq\t%%rbx, %%rsi\n\t"
571           "cpuid\n\t"
572           "xchgq\t%%rbx, %%rsi\n\t"
573           : "=a"(*rEAX), "=S"(*rEBX), "=c"(*rECX), "=d"(*rEDX)
574           : "a"(value), "c"(subleaf));
575   return false;
576 #elif defined(__i386__)
577   __asm__("movl\t%%ebx, %%esi\n\t"
578           "cpuid\n\t"
579           "xchgl\t%%ebx, %%esi\n\t"
580           : "=a"(*rEAX), "=S"(*rEBX), "=c"(*rECX), "=d"(*rEDX)
581           : "a"(value), "c"(subleaf));
582   return false;
583 #else
584   return true;
585 #endif
586 #elif defined(_MSC_VER)
587   int registers[4];
588   __cpuidex(registers, value, subleaf);
589   *rEAX = registers[0];
590   *rEBX = registers[1];
591   *rECX = registers[2];
592   *rEDX = registers[3];
593   return false;
594 #else
595   return true;
596 #endif
597 }
598 
599 // Read control register 0 (XCR0). Used to detect features such as AVX.
600 static bool getX86XCR0(unsigned *rEAX, unsigned *rEDX) {
601 #if defined(__GNUC__) || defined(__clang__)
602   // Check xgetbv; this uses a .byte sequence instead of the instruction
603   // directly because older assemblers do not include support for xgetbv and
604   // there is no easy way to conditionally compile based on the assembler used.
605   __asm__(".byte 0x0f, 0x01, 0xd0" : "=a"(*rEAX), "=d"(*rEDX) : "c"(0));
606   return false;
607 #elif defined(_MSC_FULL_VER) && defined(_XCR_XFEATURE_ENABLED_MASK)
608   unsigned long long Result = _xgetbv(_XCR_XFEATURE_ENABLED_MASK);
609   *rEAX = Result;
610   *rEDX = Result >> 32;
611   return false;
612 #else
613   return true;
614 #endif
615 }
616 
617 static void detectX86FamilyModel(unsigned EAX, unsigned *Family,
618                                  unsigned *Model) {
619   *Family = (EAX >> 8) & 0xf; // Bits 8 - 11
620   *Model = (EAX >> 4) & 0xf;  // Bits 4 - 7
621   if (*Family == 6 || *Family == 0xf) {
622     if (*Family == 0xf)
623       // Examine extended family ID if family ID is F.
624       *Family += (EAX >> 20) & 0xff; // Bits 20 - 27
625     // Examine extended model ID if family ID is 6 or F.
626     *Model += ((EAX >> 16) & 0xf) << 4; // Bits 16 - 19
627   }
628 }
629 
630 static StringRef
631 getIntelProcessorTypeAndSubtype(unsigned Family, unsigned Model,
632                                 const unsigned *Features,
633                                 unsigned *Type, unsigned *Subtype) {
634   auto testFeature = [&](unsigned F) {
635     return (Features[F / 32] & (1U << (F % 32))) != 0;
636   };
637 
638   StringRef CPU;
639 
640   switch (Family) {
641   case 3:
642     CPU = "i386";
643     break;
644   case 4:
645     CPU = "i486";
646     break;
647   case 5:
648     if (testFeature(X86::FEATURE_MMX)) {
649       CPU = "pentium-mmx";
650       break;
651     }
652     CPU = "pentium";
653     break;
654   case 6:
655     switch (Model) {
656     case 0x0f: // Intel Core 2 Duo processor, Intel Core 2 Duo mobile
657                // processor, Intel Core 2 Quad processor, Intel Core 2 Quad
658                // mobile processor, Intel Core 2 Extreme processor, Intel
659                // Pentium Dual-Core processor, Intel Xeon processor, model
660                // 0Fh. All processors are manufactured using the 65 nm process.
661     case 0x16: // Intel Celeron processor model 16h. All processors are
662                // manufactured using the 65 nm process
663       CPU = "core2";
664       *Type = X86::INTEL_CORE2;
665       break;
666     case 0x17: // Intel Core 2 Extreme processor, Intel Xeon processor, model
667                // 17h. All processors are manufactured using the 45 nm process.
668                //
669                // 45nm: Penryn , Wolfdale, Yorkfield (XE)
670     case 0x1d: // Intel Xeon processor MP. All processors are manufactured using
671                // the 45 nm process.
672       CPU = "penryn";
673       *Type = X86::INTEL_CORE2;
674       break;
675     case 0x1a: // Intel Core i7 processor and Intel Xeon processor. All
676                // processors are manufactured using the 45 nm process.
677     case 0x1e: // Intel(R) Core(TM) i7 CPU         870  @ 2.93GHz.
678                // As found in a Summer 2010 model iMac.
679     case 0x1f:
680     case 0x2e:              // Nehalem EX
681       CPU = "nehalem";
682       *Type = X86::INTEL_COREI7;
683       *Subtype = X86::INTEL_COREI7_NEHALEM;
684       break;
685     case 0x25: // Intel Core i7, laptop version.
686     case 0x2c: // Intel Core i7 processor and Intel Xeon processor. All
687                // processors are manufactured using the 32 nm process.
688     case 0x2f: // Westmere EX
689       CPU = "westmere";
690       *Type = X86::INTEL_COREI7;
691       *Subtype = X86::INTEL_COREI7_WESTMERE;
692       break;
693     case 0x2a: // Intel Core i7 processor. All processors are manufactured
694                // using the 32 nm process.
695     case 0x2d:
696       CPU = "sandybridge";
697       *Type = X86::INTEL_COREI7;
698       *Subtype = X86::INTEL_COREI7_SANDYBRIDGE;
699       break;
700     case 0x3a:
701     case 0x3e:              // Ivy Bridge EP
702       CPU = "ivybridge";
703       *Type = X86::INTEL_COREI7;
704       *Subtype = X86::INTEL_COREI7_IVYBRIDGE;
705       break;
706 
707     // Haswell:
708     case 0x3c:
709     case 0x3f:
710     case 0x45:
711     case 0x46:
712       CPU = "haswell";
713       *Type = X86::INTEL_COREI7;
714       *Subtype = X86::INTEL_COREI7_HASWELL;
715       break;
716 
717     // Broadwell:
718     case 0x3d:
719     case 0x47:
720     case 0x4f:
721     case 0x56:
722       CPU = "broadwell";
723       *Type = X86::INTEL_COREI7;
724       *Subtype = X86::INTEL_COREI7_BROADWELL;
725       break;
726 
727     // Skylake:
728     case 0x4e:              // Skylake mobile
729     case 0x5e:              // Skylake desktop
730     case 0x8e:              // Kaby Lake mobile
731     case 0x9e:              // Kaby Lake desktop
732     case 0xa5:              // Comet Lake-H/S
733     case 0xa6:              // Comet Lake-U
734       CPU = "skylake";
735       *Type = X86::INTEL_COREI7;
736       *Subtype = X86::INTEL_COREI7_SKYLAKE;
737       break;
738 
739     // Rocketlake:
740     case 0xa7:
741       CPU = "rocketlake";
742       *Type = X86::INTEL_COREI7;
743       *Subtype = X86::INTEL_COREI7_ROCKETLAKE;
744       break;
745 
746     // Skylake Xeon:
747     case 0x55:
748       *Type = X86::INTEL_COREI7;
749       if (testFeature(X86::FEATURE_AVX512BF16)) {
750         CPU = "cooperlake";
751         *Subtype = X86::INTEL_COREI7_COOPERLAKE;
752       } else if (testFeature(X86::FEATURE_AVX512VNNI)) {
753         CPU = "cascadelake";
754         *Subtype = X86::INTEL_COREI7_CASCADELAKE;
755       } else {
756         CPU = "skylake-avx512";
757         *Subtype = X86::INTEL_COREI7_SKYLAKE_AVX512;
758       }
759       break;
760 
761     // Cannonlake:
762     case 0x66:
763       CPU = "cannonlake";
764       *Type = X86::INTEL_COREI7;
765       *Subtype = X86::INTEL_COREI7_CANNONLAKE;
766       break;
767 
768     // Icelake:
769     case 0x7d:
770     case 0x7e:
771       CPU = "icelake-client";
772       *Type = X86::INTEL_COREI7;
773       *Subtype = X86::INTEL_COREI7_ICELAKE_CLIENT;
774       break;
775 
776     // Tigerlake:
777     case 0x8c:
778     case 0x8d:
779       CPU = "tigerlake";
780       *Type = X86::INTEL_COREI7;
781       *Subtype = X86::INTEL_COREI7_TIGERLAKE;
782       break;
783 
784     // Alderlake:
785     case 0x97:
786     case 0x9a:
787       CPU = "alderlake";
788       *Type = X86::INTEL_COREI7;
789       *Subtype = X86::INTEL_COREI7_ALDERLAKE;
790       break;
791 
792     // Icelake Xeon:
793     case 0x6a:
794     case 0x6c:
795       CPU = "icelake-server";
796       *Type = X86::INTEL_COREI7;
797       *Subtype = X86::INTEL_COREI7_ICELAKE_SERVER;
798       break;
799 
800     // Sapphire Rapids:
801     case 0x8f:
802       CPU = "sapphirerapids";
803       *Type = X86::INTEL_COREI7;
804       *Subtype = X86::INTEL_COREI7_SAPPHIRERAPIDS;
805       break;
806 
807     case 0x1c: // Most 45 nm Intel Atom processors
808     case 0x26: // 45 nm Atom Lincroft
809     case 0x27: // 32 nm Atom Medfield
810     case 0x35: // 32 nm Atom Midview
811     case 0x36: // 32 nm Atom Midview
812       CPU = "bonnell";
813       *Type = X86::INTEL_BONNELL;
814       break;
815 
816     // Atom Silvermont codes from the Intel software optimization guide.
817     case 0x37:
818     case 0x4a:
819     case 0x4d:
820     case 0x5a:
821     case 0x5d:
822     case 0x4c: // really airmont
823       CPU = "silvermont";
824       *Type = X86::INTEL_SILVERMONT;
825       break;
826     // Goldmont:
827     case 0x5c: // Apollo Lake
828     case 0x5f: // Denverton
829       CPU = "goldmont";
830       *Type = X86::INTEL_GOLDMONT;
831       break;
832     case 0x7a:
833       CPU = "goldmont-plus";
834       *Type = X86::INTEL_GOLDMONT_PLUS;
835       break;
836     case 0x86:
837       CPU = "tremont";
838       *Type = X86::INTEL_TREMONT;
839       break;
840 
841     // Xeon Phi (Knights Landing + Knights Mill):
842     case 0x57:
843       CPU = "knl";
844       *Type = X86::INTEL_KNL;
845       break;
846     case 0x85:
847       CPU = "knm";
848       *Type = X86::INTEL_KNM;
849       break;
850 
851     default: // Unknown family 6 CPU, try to guess.
852       // Don't both with Type/Subtype here, they aren't used by the caller.
853       // They're used above to keep the code in sync with compiler-rt.
854       // TODO detect tigerlake host from model
855       if (testFeature(X86::FEATURE_AVX512VP2INTERSECT)) {
856         CPU = "tigerlake";
857       } else if (testFeature(X86::FEATURE_AVX512VBMI2)) {
858         CPU = "icelake-client";
859       } else if (testFeature(X86::FEATURE_AVX512VBMI)) {
860         CPU = "cannonlake";
861       } else if (testFeature(X86::FEATURE_AVX512BF16)) {
862         CPU = "cooperlake";
863       } else if (testFeature(X86::FEATURE_AVX512VNNI)) {
864         CPU = "cascadelake";
865       } else if (testFeature(X86::FEATURE_AVX512VL)) {
866         CPU = "skylake-avx512";
867       } else if (testFeature(X86::FEATURE_AVX512ER)) {
868         CPU = "knl";
869       } else if (testFeature(X86::FEATURE_CLFLUSHOPT)) {
870         if (testFeature(X86::FEATURE_SHA))
871           CPU = "goldmont";
872         else
873           CPU = "skylake";
874       } else if (testFeature(X86::FEATURE_ADX)) {
875         CPU = "broadwell";
876       } else if (testFeature(X86::FEATURE_AVX2)) {
877         CPU = "haswell";
878       } else if (testFeature(X86::FEATURE_AVX)) {
879         CPU = "sandybridge";
880       } else if (testFeature(X86::FEATURE_SSE4_2)) {
881         if (testFeature(X86::FEATURE_MOVBE))
882           CPU = "silvermont";
883         else
884           CPU = "nehalem";
885       } else if (testFeature(X86::FEATURE_SSE4_1)) {
886         CPU = "penryn";
887       } else if (testFeature(X86::FEATURE_SSSE3)) {
888         if (testFeature(X86::FEATURE_MOVBE))
889           CPU = "bonnell";
890         else
891           CPU = "core2";
892       } else if (testFeature(X86::FEATURE_64BIT)) {
893         CPU = "core2";
894       } else if (testFeature(X86::FEATURE_SSE3)) {
895         CPU = "yonah";
896       } else if (testFeature(X86::FEATURE_SSE2)) {
897         CPU = "pentium-m";
898       } else if (testFeature(X86::FEATURE_SSE)) {
899         CPU = "pentium3";
900       } else if (testFeature(X86::FEATURE_MMX)) {
901         CPU = "pentium2";
902       } else {
903         CPU = "pentiumpro";
904       }
905       break;
906     }
907     break;
908   case 15: {
909     if (testFeature(X86::FEATURE_64BIT)) {
910       CPU = "nocona";
911       break;
912     }
913     if (testFeature(X86::FEATURE_SSE3)) {
914       CPU = "prescott";
915       break;
916     }
917     CPU = "pentium4";
918     break;
919   }
920   default:
921     break; // Unknown.
922   }
923 
924   return CPU;
925 }
926 
927 static StringRef
928 getAMDProcessorTypeAndSubtype(unsigned Family, unsigned Model,
929                               const unsigned *Features,
930                               unsigned *Type, unsigned *Subtype) {
931   auto testFeature = [&](unsigned F) {
932     return (Features[F / 32] & (1U << (F % 32))) != 0;
933   };
934 
935   StringRef CPU;
936 
937   switch (Family) {
938   case 4:
939     CPU = "i486";
940     break;
941   case 5:
942     CPU = "pentium";
943     switch (Model) {
944     case 6:
945     case 7:
946       CPU = "k6";
947       break;
948     case 8:
949       CPU = "k6-2";
950       break;
951     case 9:
952     case 13:
953       CPU = "k6-3";
954       break;
955     case 10:
956       CPU = "geode";
957       break;
958     }
959     break;
960   case 6:
961     if (testFeature(X86::FEATURE_SSE)) {
962       CPU = "athlon-xp";
963       break;
964     }
965     CPU = "athlon";
966     break;
967   case 15:
968     if (testFeature(X86::FEATURE_SSE3)) {
969       CPU = "k8-sse3";
970       break;
971     }
972     CPU = "k8";
973     break;
974   case 16:
975     CPU = "amdfam10";
976     *Type = X86::AMDFAM10H; // "amdfam10"
977     switch (Model) {
978     case 2:
979       *Subtype = X86::AMDFAM10H_BARCELONA;
980       break;
981     case 4:
982       *Subtype = X86::AMDFAM10H_SHANGHAI;
983       break;
984     case 8:
985       *Subtype = X86::AMDFAM10H_ISTANBUL;
986       break;
987     }
988     break;
989   case 20:
990     CPU = "btver1";
991     *Type = X86::AMD_BTVER1;
992     break;
993   case 21:
994     CPU = "bdver1";
995     *Type = X86::AMDFAM15H;
996     if (Model >= 0x60 && Model <= 0x7f) {
997       CPU = "bdver4";
998       *Subtype = X86::AMDFAM15H_BDVER4;
999       break; // 60h-7Fh: Excavator
1000     }
1001     if (Model >= 0x30 && Model <= 0x3f) {
1002       CPU = "bdver3";
1003       *Subtype = X86::AMDFAM15H_BDVER3;
1004       break; // 30h-3Fh: Steamroller
1005     }
1006     if ((Model >= 0x10 && Model <= 0x1f) || Model == 0x02) {
1007       CPU = "bdver2";
1008       *Subtype = X86::AMDFAM15H_BDVER2;
1009       break; // 02h, 10h-1Fh: Piledriver
1010     }
1011     if (Model <= 0x0f) {
1012       *Subtype = X86::AMDFAM15H_BDVER1;
1013       break; // 00h-0Fh: Bulldozer
1014     }
1015     break;
1016   case 22:
1017     CPU = "btver2";
1018     *Type = X86::AMD_BTVER2;
1019     break;
1020   case 23:
1021     CPU = "znver1";
1022     *Type = X86::AMDFAM17H;
1023     if ((Model >= 0x30 && Model <= 0x3f) || Model == 0x71) {
1024       CPU = "znver2";
1025       *Subtype = X86::AMDFAM17H_ZNVER2;
1026       break; // 30h-3fh, 71h: Zen2
1027     }
1028     if (Model <= 0x0f) {
1029       *Subtype = X86::AMDFAM17H_ZNVER1;
1030       break; // 00h-0Fh: Zen1
1031     }
1032     break;
1033   case 25:
1034     CPU = "znver3";
1035     *Type = X86::AMDFAM19H;
1036     if (Model <= 0x0f) {
1037       *Subtype = X86::AMDFAM19H_ZNVER3;
1038       break; // 00h-0Fh: Zen3
1039     }
1040     break;
1041   default:
1042     break; // Unknown AMD CPU.
1043   }
1044 
1045   return CPU;
1046 }
1047 
1048 static void getAvailableFeatures(unsigned ECX, unsigned EDX, unsigned MaxLeaf,
1049                                  unsigned *Features) {
1050   unsigned EAX, EBX;
1051 
1052   auto setFeature = [&](unsigned F) {
1053     Features[F / 32] |= 1U << (F % 32);
1054   };
1055 
1056   if ((EDX >> 15) & 1)
1057     setFeature(X86::FEATURE_CMOV);
1058   if ((EDX >> 23) & 1)
1059     setFeature(X86::FEATURE_MMX);
1060   if ((EDX >> 25) & 1)
1061     setFeature(X86::FEATURE_SSE);
1062   if ((EDX >> 26) & 1)
1063     setFeature(X86::FEATURE_SSE2);
1064 
1065   if ((ECX >> 0) & 1)
1066     setFeature(X86::FEATURE_SSE3);
1067   if ((ECX >> 1) & 1)
1068     setFeature(X86::FEATURE_PCLMUL);
1069   if ((ECX >> 9) & 1)
1070     setFeature(X86::FEATURE_SSSE3);
1071   if ((ECX >> 12) & 1)
1072     setFeature(X86::FEATURE_FMA);
1073   if ((ECX >> 19) & 1)
1074     setFeature(X86::FEATURE_SSE4_1);
1075   if ((ECX >> 20) & 1) {
1076     setFeature(X86::FEATURE_SSE4_2);
1077     setFeature(X86::FEATURE_CRC32);
1078   }
1079   if ((ECX >> 23) & 1)
1080     setFeature(X86::FEATURE_POPCNT);
1081   if ((ECX >> 25) & 1)
1082     setFeature(X86::FEATURE_AES);
1083 
1084   if ((ECX >> 22) & 1)
1085     setFeature(X86::FEATURE_MOVBE);
1086 
1087   // If CPUID indicates support for XSAVE, XRESTORE and AVX, and XGETBV
1088   // indicates that the AVX registers will be saved and restored on context
1089   // switch, then we have full AVX support.
1090   const unsigned AVXBits = (1 << 27) | (1 << 28);
1091   bool HasAVX = ((ECX & AVXBits) == AVXBits) && !getX86XCR0(&EAX, &EDX) &&
1092                 ((EAX & 0x6) == 0x6);
1093 #if defined(__APPLE__)
1094   // Darwin lazily saves the AVX512 context on first use: trust that the OS will
1095   // save the AVX512 context if we use AVX512 instructions, even the bit is not
1096   // set right now.
1097   bool HasAVX512Save = true;
1098 #else
1099   // AVX512 requires additional context to be saved by the OS.
1100   bool HasAVX512Save = HasAVX && ((EAX & 0xe0) == 0xe0);
1101 #endif
1102 
1103   if (HasAVX)
1104     setFeature(X86::FEATURE_AVX);
1105 
1106   bool HasLeaf7 =
1107       MaxLeaf >= 0x7 && !getX86CpuIDAndInfoEx(0x7, 0x0, &EAX, &EBX, &ECX, &EDX);
1108 
1109   if (HasLeaf7 && ((EBX >> 3) & 1))
1110     setFeature(X86::FEATURE_BMI);
1111   if (HasLeaf7 && ((EBX >> 5) & 1) && HasAVX)
1112     setFeature(X86::FEATURE_AVX2);
1113   if (HasLeaf7 && ((EBX >> 8) & 1))
1114     setFeature(X86::FEATURE_BMI2);
1115   if (HasLeaf7 && ((EBX >> 16) & 1) && HasAVX512Save)
1116     setFeature(X86::FEATURE_AVX512F);
1117   if (HasLeaf7 && ((EBX >> 17) & 1) && HasAVX512Save)
1118     setFeature(X86::FEATURE_AVX512DQ);
1119   if (HasLeaf7 && ((EBX >> 19) & 1))
1120     setFeature(X86::FEATURE_ADX);
1121   if (HasLeaf7 && ((EBX >> 21) & 1) && HasAVX512Save)
1122     setFeature(X86::FEATURE_AVX512IFMA);
1123   if (HasLeaf7 && ((EBX >> 23) & 1))
1124     setFeature(X86::FEATURE_CLFLUSHOPT);
1125   if (HasLeaf7 && ((EBX >> 26) & 1) && HasAVX512Save)
1126     setFeature(X86::FEATURE_AVX512PF);
1127   if (HasLeaf7 && ((EBX >> 27) & 1) && HasAVX512Save)
1128     setFeature(X86::FEATURE_AVX512ER);
1129   if (HasLeaf7 && ((EBX >> 28) & 1) && HasAVX512Save)
1130     setFeature(X86::FEATURE_AVX512CD);
1131   if (HasLeaf7 && ((EBX >> 29) & 1))
1132     setFeature(X86::FEATURE_SHA);
1133   if (HasLeaf7 && ((EBX >> 30) & 1) && HasAVX512Save)
1134     setFeature(X86::FEATURE_AVX512BW);
1135   if (HasLeaf7 && ((EBX >> 31) & 1) && HasAVX512Save)
1136     setFeature(X86::FEATURE_AVX512VL);
1137 
1138   if (HasLeaf7 && ((ECX >> 1) & 1) && HasAVX512Save)
1139     setFeature(X86::FEATURE_AVX512VBMI);
1140   if (HasLeaf7 && ((ECX >> 6) & 1) && HasAVX512Save)
1141     setFeature(X86::FEATURE_AVX512VBMI2);
1142   if (HasLeaf7 && ((ECX >> 8) & 1))
1143     setFeature(X86::FEATURE_GFNI);
1144   if (HasLeaf7 && ((ECX >> 10) & 1) && HasAVX)
1145     setFeature(X86::FEATURE_VPCLMULQDQ);
1146   if (HasLeaf7 && ((ECX >> 11) & 1) && HasAVX512Save)
1147     setFeature(X86::FEATURE_AVX512VNNI);
1148   if (HasLeaf7 && ((ECX >> 12) & 1) && HasAVX512Save)
1149     setFeature(X86::FEATURE_AVX512BITALG);
1150   if (HasLeaf7 && ((ECX >> 14) & 1) && HasAVX512Save)
1151     setFeature(X86::FEATURE_AVX512VPOPCNTDQ);
1152 
1153   if (HasLeaf7 && ((EDX >> 2) & 1) && HasAVX512Save)
1154     setFeature(X86::FEATURE_AVX5124VNNIW);
1155   if (HasLeaf7 && ((EDX >> 3) & 1) && HasAVX512Save)
1156     setFeature(X86::FEATURE_AVX5124FMAPS);
1157   if (HasLeaf7 && ((EDX >> 8) & 1) && HasAVX512Save)
1158     setFeature(X86::FEATURE_AVX512VP2INTERSECT);
1159 
1160   bool HasLeaf7Subleaf1 =
1161       MaxLeaf >= 7 && !getX86CpuIDAndInfoEx(0x7, 0x1, &EAX, &EBX, &ECX, &EDX);
1162   if (HasLeaf7Subleaf1 && ((EAX >> 5) & 1) && HasAVX512Save)
1163     setFeature(X86::FEATURE_AVX512BF16);
1164 
1165   unsigned MaxExtLevel;
1166   getX86CpuIDAndInfo(0x80000000, &MaxExtLevel, &EBX, &ECX, &EDX);
1167 
1168   bool HasExtLeaf1 = MaxExtLevel >= 0x80000001 &&
1169                      !getX86CpuIDAndInfo(0x80000001, &EAX, &EBX, &ECX, &EDX);
1170   if (HasExtLeaf1 && ((ECX >> 6) & 1))
1171     setFeature(X86::FEATURE_SSE4_A);
1172   if (HasExtLeaf1 && ((ECX >> 11) & 1))
1173     setFeature(X86::FEATURE_XOP);
1174   if (HasExtLeaf1 && ((ECX >> 16) & 1))
1175     setFeature(X86::FEATURE_FMA4);
1176 
1177   if (HasExtLeaf1 && ((EDX >> 29) & 1))
1178     setFeature(X86::FEATURE_64BIT);
1179 }
1180 
1181 StringRef sys::getHostCPUName() {
1182   unsigned MaxLeaf = 0;
1183   const VendorSignatures Vendor = getVendorSignature(&MaxLeaf);
1184   if (Vendor == VendorSignatures::UNKNOWN)
1185     return "generic";
1186 
1187   unsigned EAX = 0, EBX = 0, ECX = 0, EDX = 0;
1188   getX86CpuIDAndInfo(0x1, &EAX, &EBX, &ECX, &EDX);
1189 
1190   unsigned Family = 0, Model = 0;
1191   unsigned Features[(X86::CPU_FEATURE_MAX + 31) / 32] = {0};
1192   detectX86FamilyModel(EAX, &Family, &Model);
1193   getAvailableFeatures(ECX, EDX, MaxLeaf, Features);
1194 
1195   // These aren't consumed in this file, but we try to keep some source code the
1196   // same or similar to compiler-rt.
1197   unsigned Type = 0;
1198   unsigned Subtype = 0;
1199 
1200   StringRef CPU;
1201 
1202   if (Vendor == VendorSignatures::GENUINE_INTEL) {
1203     CPU = getIntelProcessorTypeAndSubtype(Family, Model, Features, &Type,
1204                                           &Subtype);
1205   } else if (Vendor == VendorSignatures::AUTHENTIC_AMD) {
1206     CPU = getAMDProcessorTypeAndSubtype(Family, Model, Features, &Type,
1207                                         &Subtype);
1208   }
1209 
1210   if (!CPU.empty())
1211     return CPU;
1212 
1213   return "generic";
1214 }
1215 
1216 #elif defined(__APPLE__) && (defined(__ppc__) || defined(__powerpc__))
1217 StringRef sys::getHostCPUName() {
1218   host_basic_info_data_t hostInfo;
1219   mach_msg_type_number_t infoCount;
1220 
1221   infoCount = HOST_BASIC_INFO_COUNT;
1222   mach_port_t hostPort = mach_host_self();
1223   host_info(hostPort, HOST_BASIC_INFO, (host_info_t)&hostInfo,
1224             &infoCount);
1225   mach_port_deallocate(mach_task_self(), hostPort);
1226 
1227   if (hostInfo.cpu_type != CPU_TYPE_POWERPC)
1228     return "generic";
1229 
1230   switch (hostInfo.cpu_subtype) {
1231   case CPU_SUBTYPE_POWERPC_601:
1232     return "601";
1233   case CPU_SUBTYPE_POWERPC_602:
1234     return "602";
1235   case CPU_SUBTYPE_POWERPC_603:
1236     return "603";
1237   case CPU_SUBTYPE_POWERPC_603e:
1238     return "603e";
1239   case CPU_SUBTYPE_POWERPC_603ev:
1240     return "603ev";
1241   case CPU_SUBTYPE_POWERPC_604:
1242     return "604";
1243   case CPU_SUBTYPE_POWERPC_604e:
1244     return "604e";
1245   case CPU_SUBTYPE_POWERPC_620:
1246     return "620";
1247   case CPU_SUBTYPE_POWERPC_750:
1248     return "750";
1249   case CPU_SUBTYPE_POWERPC_7400:
1250     return "7400";
1251   case CPU_SUBTYPE_POWERPC_7450:
1252     return "7450";
1253   case CPU_SUBTYPE_POWERPC_970:
1254     return "970";
1255   default:;
1256   }
1257 
1258   return "generic";
1259 }
1260 #elif defined(__linux__) && (defined(__ppc__) || defined(__powerpc__))
1261 StringRef sys::getHostCPUName() {
1262   std::unique_ptr<llvm::MemoryBuffer> P = getProcCpuinfoContent();
1263   StringRef Content = P ? P->getBuffer() : "";
1264   return detail::getHostCPUNameForPowerPC(Content);
1265 }
1266 #elif defined(__linux__) && (defined(__arm__) || defined(__aarch64__))
1267 StringRef sys::getHostCPUName() {
1268   std::unique_ptr<llvm::MemoryBuffer> P = getProcCpuinfoContent();
1269   StringRef Content = P ? P->getBuffer() : "";
1270   return detail::getHostCPUNameForARM(Content);
1271 }
1272 #elif defined(__linux__) && defined(__s390x__)
1273 StringRef sys::getHostCPUName() {
1274   std::unique_ptr<llvm::MemoryBuffer> P = getProcCpuinfoContent();
1275   StringRef Content = P ? P->getBuffer() : "";
1276   return detail::getHostCPUNameForS390x(Content);
1277 }
1278 #elif defined(__MVS__)
1279 StringRef sys::getHostCPUName() {
1280   // Get pointer to Communications Vector Table (CVT).
1281   // The pointer is located at offset 16 of the Prefixed Save Area (PSA).
1282   // It is stored as 31 bit pointer and will be zero-extended to 64 bit.
1283   int *StartToCVTOffset = reinterpret_cast<int *>(0x10);
1284   // Since its stored as a 31-bit pointer, get the 4 bytes from the start
1285   // of address.
1286   int ReadValue = *StartToCVTOffset;
1287   // Explicitly clear the high order bit.
1288   ReadValue = (ReadValue & 0x7FFFFFFF);
1289   char *CVT = reinterpret_cast<char *>(ReadValue);
1290   // The model number is located in the CVT prefix at offset -6 and stored as
1291   // signless packed decimal.
1292   uint16_t Id = *(uint16_t *)&CVT[-6];
1293   // Convert number to integer.
1294   Id = decodePackedBCD<uint16_t>(Id, false);
1295   // Check for vector support. It's stored in field CVTFLAG5 (offset 244),
1296   // bit CVTVEF (X'80'). The facilities list is part of the PSA but the vector
1297   // extension can only be used if bit CVTVEF is on.
1298   bool HaveVectorSupport = CVT[244] & 0x80;
1299   return getCPUNameFromS390Model(Id, HaveVectorSupport);
1300 }
1301 #elif defined(__APPLE__) && defined(__aarch64__)
1302 StringRef sys::getHostCPUName() {
1303   return "cyclone";
1304 }
1305 #elif defined(__APPLE__) && defined(__arm__)
1306 StringRef sys::getHostCPUName() {
1307   host_basic_info_data_t hostInfo;
1308   mach_msg_type_number_t infoCount;
1309 
1310   infoCount = HOST_BASIC_INFO_COUNT;
1311   mach_port_t hostPort = mach_host_self();
1312   host_info(hostPort, HOST_BASIC_INFO, (host_info_t)&hostInfo,
1313             &infoCount);
1314   mach_port_deallocate(mach_task_self(), hostPort);
1315 
1316   if (hostInfo.cpu_type != CPU_TYPE_ARM) {
1317     assert(false && "CPUType not equal to ARM should not be possible on ARM");
1318     return "generic";
1319   }
1320   switch (hostInfo.cpu_subtype) {
1321     case CPU_SUBTYPE_ARM_V7S:
1322       return "swift";
1323     default:;
1324     }
1325 
1326   return "generic";
1327 }
1328 #elif defined(_AIX)
1329 StringRef sys::getHostCPUName() {
1330   switch (_system_configuration.implementation) {
1331   case POWER_4:
1332     if (_system_configuration.version == PV_4_3)
1333       return "970";
1334     return "pwr4";
1335   case POWER_5:
1336     if (_system_configuration.version == PV_5)
1337       return "pwr5";
1338     return "pwr5x";
1339   case POWER_6:
1340     if (_system_configuration.version == PV_6_Compat)
1341       return "pwr6";
1342     return "pwr6x";
1343   case POWER_7:
1344     return "pwr7";
1345   case POWER_8:
1346     return "pwr8";
1347   case POWER_9:
1348     return "pwr9";
1349 // TODO: simplify this once the macro is available in all OS levels.
1350 #ifdef POWER_10
1351   case POWER_10:
1352 #else
1353   case 0x40000:
1354 #endif
1355     return "pwr10";
1356   default:
1357     return "generic";
1358   }
1359 }
1360 #elif defined(__riscv)
1361 StringRef sys::getHostCPUName() {
1362 #if __riscv_xlen == 64
1363   return "generic-rv64";
1364 #elif __riscv_xlen == 32
1365   return "generic-rv32";
1366 #else
1367 #error "Unhandled value of __riscv_xlen"
1368 #endif
1369 }
1370 #else
1371 StringRef sys::getHostCPUName() { return "generic"; }
1372 namespace llvm {
1373 namespace sys {
1374 namespace detail {
1375 namespace x86 {
1376 
1377 VendorSignatures getVendorSignature(unsigned *MaxLeaf) {
1378   return VendorSignatures::UNKNOWN;
1379 }
1380 
1381 } // namespace x86
1382 } // namespace detail
1383 } // namespace sys
1384 } // namespace llvm
1385 #endif
1386 
1387 #if defined(__linux__) && (defined(__i386__) || defined(__x86_64__))
1388 // On Linux, the number of physical cores can be computed from /proc/cpuinfo,
1389 // using the number of unique physical/core id pairs. The following
1390 // implementation reads the /proc/cpuinfo format on an x86_64 system.
1391 int computeHostNumPhysicalCores() {
1392   // Enabled represents the number of physical id/core id pairs with at least
1393   // one processor id enabled by the CPU affinity mask.
1394   cpu_set_t Affinity, Enabled;
1395   if (sched_getaffinity(0, sizeof(Affinity), &Affinity) != 0)
1396     return -1;
1397   CPU_ZERO(&Enabled);
1398 
1399   // Read /proc/cpuinfo as a stream (until EOF reached). It cannot be
1400   // mmapped because it appears to have 0 size.
1401   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> Text =
1402       llvm::MemoryBuffer::getFileAsStream("/proc/cpuinfo");
1403   if (std::error_code EC = Text.getError()) {
1404     llvm::errs() << "Can't read "
1405                  << "/proc/cpuinfo: " << EC.message() << "\n";
1406     return -1;
1407   }
1408   SmallVector<StringRef, 8> strs;
1409   (*Text)->getBuffer().split(strs, "\n", /*MaxSplit=*/-1,
1410                              /*KeepEmpty=*/false);
1411   int CurProcessor = -1;
1412   int CurPhysicalId = -1;
1413   int CurSiblings = -1;
1414   int CurCoreId = -1;
1415   for (StringRef Line : strs) {
1416     std::pair<StringRef, StringRef> Data = Line.split(':');
1417     auto Name = Data.first.trim();
1418     auto Val = Data.second.trim();
1419     // These fields are available if the kernel is configured with CONFIG_SMP.
1420     if (Name == "processor")
1421       Val.getAsInteger(10, CurProcessor);
1422     else if (Name == "physical id")
1423       Val.getAsInteger(10, CurPhysicalId);
1424     else if (Name == "siblings")
1425       Val.getAsInteger(10, CurSiblings);
1426     else if (Name == "core id") {
1427       Val.getAsInteger(10, CurCoreId);
1428       // The processor id corresponds to an index into cpu_set_t.
1429       if (CPU_ISSET(CurProcessor, &Affinity))
1430         CPU_SET(CurPhysicalId * CurSiblings + CurCoreId, &Enabled);
1431     }
1432   }
1433   return CPU_COUNT(&Enabled);
1434 }
1435 #elif defined(__linux__) && defined(__powerpc__)
1436 int computeHostNumPhysicalCores() {
1437   cpu_set_t Affinity;
1438   if (sched_getaffinity(0, sizeof(Affinity), &Affinity) == 0)
1439     return CPU_COUNT(&Affinity);
1440 
1441   // The call to sched_getaffinity() may have failed because the Affinity
1442   // mask is too small for the number of CPU's on the system (i.e. the
1443   // system has more than 1024 CPUs). Allocate a mask large enough for
1444   // twice as many CPUs.
1445   cpu_set_t *DynAffinity;
1446   DynAffinity = CPU_ALLOC(2048);
1447   if (sched_getaffinity(0, CPU_ALLOC_SIZE(2048), DynAffinity) == 0) {
1448     int NumCPUs = CPU_COUNT(DynAffinity);
1449     CPU_FREE(DynAffinity);
1450     return NumCPUs;
1451   }
1452   return -1;
1453 }
1454 #elif defined(__linux__) && defined(__s390x__)
1455 int computeHostNumPhysicalCores() { return sysconf(_SC_NPROCESSORS_ONLN); }
1456 #elif defined(__APPLE__)
1457 #include <sys/param.h>
1458 #include <sys/sysctl.h>
1459 
1460 // Gets the number of *physical cores* on the machine.
1461 int computeHostNumPhysicalCores() {
1462   uint32_t count;
1463   size_t len = sizeof(count);
1464   sysctlbyname("hw.physicalcpu", &count, &len, NULL, 0);
1465   if (count < 1) {
1466     int nm[2];
1467     nm[0] = CTL_HW;
1468     nm[1] = HW_AVAILCPU;
1469     sysctl(nm, 2, &count, &len, NULL, 0);
1470     if (count < 1)
1471       return -1;
1472   }
1473   return count;
1474 }
1475 #elif defined(__MVS__)
1476 int computeHostNumPhysicalCores() {
1477   enum {
1478     // Byte offset of the pointer to the Communications Vector Table (CVT) in
1479     // the Prefixed Save Area (PSA). The table entry is a 31-bit pointer and
1480     // will be zero-extended to uintptr_t.
1481     FLCCVT = 16,
1482     // Byte offset of the pointer to the Common System Data Area (CSD) in the
1483     // CVT. The table entry is a 31-bit pointer and will be zero-extended to
1484     // uintptr_t.
1485     CVTCSD = 660,
1486     // Byte offset to the number of live CPs in the LPAR, stored as a signed
1487     // 32-bit value in the table.
1488     CSD_NUMBER_ONLINE_STANDARD_CPS = 264,
1489   };
1490   char *PSA = 0;
1491   char *CVT = reinterpret_cast<char *>(
1492       static_cast<uintptr_t>(reinterpret_cast<unsigned int &>(PSA[FLCCVT])));
1493   char *CSD = reinterpret_cast<char *>(
1494       static_cast<uintptr_t>(reinterpret_cast<unsigned int &>(CVT[CVTCSD])));
1495   return reinterpret_cast<int &>(CSD[CSD_NUMBER_ONLINE_STANDARD_CPS]);
1496 }
1497 #elif defined(_WIN32) && LLVM_ENABLE_THREADS != 0
1498 // Defined in llvm/lib/Support/Windows/Threading.inc
1499 int computeHostNumPhysicalCores();
1500 #else
1501 // On other systems, return -1 to indicate unknown.
1502 static int computeHostNumPhysicalCores() { return -1; }
1503 #endif
1504 
1505 int sys::getHostNumPhysicalCores() {
1506   static int NumCores = computeHostNumPhysicalCores();
1507   return NumCores;
1508 }
1509 
1510 #if defined(__i386__) || defined(_M_IX86) || \
1511     defined(__x86_64__) || defined(_M_X64)
1512 bool sys::getHostCPUFeatures(StringMap<bool> &Features) {
1513   unsigned EAX = 0, EBX = 0, ECX = 0, EDX = 0;
1514   unsigned MaxLevel;
1515 
1516   if (getX86CpuIDAndInfo(0, &MaxLevel, &EBX, &ECX, &EDX) || MaxLevel < 1)
1517     return false;
1518 
1519   getX86CpuIDAndInfo(1, &EAX, &EBX, &ECX, &EDX);
1520 
1521   Features["cx8"]    = (EDX >>  8) & 1;
1522   Features["cmov"]   = (EDX >> 15) & 1;
1523   Features["mmx"]    = (EDX >> 23) & 1;
1524   Features["fxsr"]   = (EDX >> 24) & 1;
1525   Features["sse"]    = (EDX >> 25) & 1;
1526   Features["sse2"]   = (EDX >> 26) & 1;
1527 
1528   Features["sse3"]   = (ECX >>  0) & 1;
1529   Features["pclmul"] = (ECX >>  1) & 1;
1530   Features["ssse3"]  = (ECX >>  9) & 1;
1531   Features["cx16"]   = (ECX >> 13) & 1;
1532   Features["sse4.1"] = (ECX >> 19) & 1;
1533   Features["sse4.2"] = (ECX >> 20) & 1;
1534   Features["crc32"]  = Features["sse4.2"];
1535   Features["movbe"]  = (ECX >> 22) & 1;
1536   Features["popcnt"] = (ECX >> 23) & 1;
1537   Features["aes"]    = (ECX >> 25) & 1;
1538   Features["rdrnd"]  = (ECX >> 30) & 1;
1539 
1540   // If CPUID indicates support for XSAVE, XRESTORE and AVX, and XGETBV
1541   // indicates that the AVX registers will be saved and restored on context
1542   // switch, then we have full AVX support.
1543   bool HasXSave = ((ECX >> 27) & 1) && !getX86XCR0(&EAX, &EDX);
1544   bool HasAVXSave = HasXSave && ((ECX >> 28) & 1) && ((EAX & 0x6) == 0x6);
1545 #if defined(__APPLE__)
1546   // Darwin lazily saves the AVX512 context on first use: trust that the OS will
1547   // save the AVX512 context if we use AVX512 instructions, even the bit is not
1548   // set right now.
1549   bool HasAVX512Save = true;
1550 #else
1551   // AVX512 requires additional context to be saved by the OS.
1552   bool HasAVX512Save = HasAVXSave && ((EAX & 0xe0) == 0xe0);
1553 #endif
1554   // AMX requires additional context to be saved by the OS.
1555   const unsigned AMXBits = (1 << 17) | (1 << 18);
1556   bool HasAMXSave = HasXSave && ((EAX & AMXBits) == AMXBits);
1557 
1558   Features["avx"]   = HasAVXSave;
1559   Features["fma"]   = ((ECX >> 12) & 1) && HasAVXSave;
1560   // Only enable XSAVE if OS has enabled support for saving YMM state.
1561   Features["xsave"] = ((ECX >> 26) & 1) && HasAVXSave;
1562   Features["f16c"]  = ((ECX >> 29) & 1) && HasAVXSave;
1563 
1564   unsigned MaxExtLevel;
1565   getX86CpuIDAndInfo(0x80000000, &MaxExtLevel, &EBX, &ECX, &EDX);
1566 
1567   bool HasExtLeaf1 = MaxExtLevel >= 0x80000001 &&
1568                      !getX86CpuIDAndInfo(0x80000001, &EAX, &EBX, &ECX, &EDX);
1569   Features["sahf"]   = HasExtLeaf1 && ((ECX >>  0) & 1);
1570   Features["lzcnt"]  = HasExtLeaf1 && ((ECX >>  5) & 1);
1571   Features["sse4a"]  = HasExtLeaf1 && ((ECX >>  6) & 1);
1572   Features["prfchw"] = HasExtLeaf1 && ((ECX >>  8) & 1);
1573   Features["xop"]    = HasExtLeaf1 && ((ECX >> 11) & 1) && HasAVXSave;
1574   Features["lwp"]    = HasExtLeaf1 && ((ECX >> 15) & 1);
1575   Features["fma4"]   = HasExtLeaf1 && ((ECX >> 16) & 1) && HasAVXSave;
1576   Features["tbm"]    = HasExtLeaf1 && ((ECX >> 21) & 1);
1577   Features["mwaitx"] = HasExtLeaf1 && ((ECX >> 29) & 1);
1578 
1579   Features["64bit"]  = HasExtLeaf1 && ((EDX >> 29) & 1);
1580 
1581   // Miscellaneous memory related features, detected by
1582   // using the 0x80000008 leaf of the CPUID instruction
1583   bool HasExtLeaf8 = MaxExtLevel >= 0x80000008 &&
1584                      !getX86CpuIDAndInfo(0x80000008, &EAX, &EBX, &ECX, &EDX);
1585   Features["clzero"]   = HasExtLeaf8 && ((EBX >> 0) & 1);
1586   Features["wbnoinvd"] = HasExtLeaf8 && ((EBX >> 9) & 1);
1587 
1588   bool HasLeaf7 =
1589       MaxLevel >= 7 && !getX86CpuIDAndInfoEx(0x7, 0x0, &EAX, &EBX, &ECX, &EDX);
1590 
1591   Features["fsgsbase"]   = HasLeaf7 && ((EBX >>  0) & 1);
1592   Features["sgx"]        = HasLeaf7 && ((EBX >>  2) & 1);
1593   Features["bmi"]        = HasLeaf7 && ((EBX >>  3) & 1);
1594   // AVX2 is only supported if we have the OS save support from AVX.
1595   Features["avx2"]       = HasLeaf7 && ((EBX >>  5) & 1) && HasAVXSave;
1596   Features["bmi2"]       = HasLeaf7 && ((EBX >>  8) & 1);
1597   Features["invpcid"]    = HasLeaf7 && ((EBX >> 10) & 1);
1598   Features["rtm"]        = HasLeaf7 && ((EBX >> 11) & 1);
1599   // AVX512 is only supported if the OS supports the context save for it.
1600   Features["avx512f"]    = HasLeaf7 && ((EBX >> 16) & 1) && HasAVX512Save;
1601   Features["avx512dq"]   = HasLeaf7 && ((EBX >> 17) & 1) && HasAVX512Save;
1602   Features["rdseed"]     = HasLeaf7 && ((EBX >> 18) & 1);
1603   Features["adx"]        = HasLeaf7 && ((EBX >> 19) & 1);
1604   Features["avx512ifma"] = HasLeaf7 && ((EBX >> 21) & 1) && HasAVX512Save;
1605   Features["clflushopt"] = HasLeaf7 && ((EBX >> 23) & 1);
1606   Features["clwb"]       = HasLeaf7 && ((EBX >> 24) & 1);
1607   Features["avx512pf"]   = HasLeaf7 && ((EBX >> 26) & 1) && HasAVX512Save;
1608   Features["avx512er"]   = HasLeaf7 && ((EBX >> 27) & 1) && HasAVX512Save;
1609   Features["avx512cd"]   = HasLeaf7 && ((EBX >> 28) & 1) && HasAVX512Save;
1610   Features["sha"]        = HasLeaf7 && ((EBX >> 29) & 1);
1611   Features["avx512bw"]   = HasLeaf7 && ((EBX >> 30) & 1) && HasAVX512Save;
1612   Features["avx512vl"]   = HasLeaf7 && ((EBX >> 31) & 1) && HasAVX512Save;
1613 
1614   Features["prefetchwt1"]     = HasLeaf7 && ((ECX >>  0) & 1);
1615   Features["avx512vbmi"]      = HasLeaf7 && ((ECX >>  1) & 1) && HasAVX512Save;
1616   Features["pku"]             = HasLeaf7 && ((ECX >>  4) & 1);
1617   Features["waitpkg"]         = HasLeaf7 && ((ECX >>  5) & 1);
1618   Features["avx512vbmi2"]     = HasLeaf7 && ((ECX >>  6) & 1) && HasAVX512Save;
1619   Features["shstk"]           = HasLeaf7 && ((ECX >>  7) & 1);
1620   Features["gfni"]            = HasLeaf7 && ((ECX >>  8) & 1);
1621   Features["vaes"]            = HasLeaf7 && ((ECX >>  9) & 1) && HasAVXSave;
1622   Features["vpclmulqdq"]      = HasLeaf7 && ((ECX >> 10) & 1) && HasAVXSave;
1623   Features["avx512vnni"]      = HasLeaf7 && ((ECX >> 11) & 1) && HasAVX512Save;
1624   Features["avx512bitalg"]    = HasLeaf7 && ((ECX >> 12) & 1) && HasAVX512Save;
1625   Features["avx512vpopcntdq"] = HasLeaf7 && ((ECX >> 14) & 1) && HasAVX512Save;
1626   Features["rdpid"]           = HasLeaf7 && ((ECX >> 22) & 1);
1627   Features["kl"]              = HasLeaf7 && ((ECX >> 23) & 1); // key locker
1628   Features["cldemote"]        = HasLeaf7 && ((ECX >> 25) & 1);
1629   Features["movdiri"]         = HasLeaf7 && ((ECX >> 27) & 1);
1630   Features["movdir64b"]       = HasLeaf7 && ((ECX >> 28) & 1);
1631   Features["enqcmd"]          = HasLeaf7 && ((ECX >> 29) & 1);
1632 
1633   Features["uintr"]           = HasLeaf7 && ((EDX >> 5) & 1);
1634   Features["avx512vp2intersect"] =
1635       HasLeaf7 && ((EDX >> 8) & 1) && HasAVX512Save;
1636   Features["serialize"]       = HasLeaf7 && ((EDX >> 14) & 1);
1637   Features["tsxldtrk"]        = HasLeaf7 && ((EDX >> 16) & 1);
1638   // There are two CPUID leafs which information associated with the pconfig
1639   // instruction:
1640   // EAX=0x7, ECX=0x0 indicates the availability of the instruction (via the 18th
1641   // bit of EDX), while the EAX=0x1b leaf returns information on the
1642   // availability of specific pconfig leafs.
1643   // The target feature here only refers to the the first of these two.
1644   // Users might need to check for the availability of specific pconfig
1645   // leaves using cpuid, since that information is ignored while
1646   // detecting features using the "-march=native" flag.
1647   // For more info, see X86 ISA docs.
1648   Features["pconfig"] = HasLeaf7 && ((EDX >> 18) & 1);
1649   Features["amx-bf16"]   = HasLeaf7 && ((EDX >> 22) & 1) && HasAMXSave;
1650   Features["avx512fp16"] = HasLeaf7 && ((EDX >> 23) & 1) && HasAVX512Save;
1651   Features["amx-tile"]   = HasLeaf7 && ((EDX >> 24) & 1) && HasAMXSave;
1652   Features["amx-int8"]   = HasLeaf7 && ((EDX >> 25) & 1) && HasAMXSave;
1653   bool HasLeaf7Subleaf1 =
1654       MaxLevel >= 7 && !getX86CpuIDAndInfoEx(0x7, 0x1, &EAX, &EBX, &ECX, &EDX);
1655   Features["avxvnni"]    = HasLeaf7Subleaf1 && ((EAX >> 4) & 1) && HasAVXSave;
1656   Features["avx512bf16"] = HasLeaf7Subleaf1 && ((EAX >> 5) & 1) && HasAVX512Save;
1657   Features["hreset"]     = HasLeaf7Subleaf1 && ((EAX >> 22) & 1);
1658 
1659   bool HasLeafD = MaxLevel >= 0xd &&
1660                   !getX86CpuIDAndInfoEx(0xd, 0x1, &EAX, &EBX, &ECX, &EDX);
1661 
1662   // Only enable XSAVE if OS has enabled support for saving YMM state.
1663   Features["xsaveopt"] = HasLeafD && ((EAX >> 0) & 1) && HasAVXSave;
1664   Features["xsavec"]   = HasLeafD && ((EAX >> 1) & 1) && HasAVXSave;
1665   Features["xsaves"]   = HasLeafD && ((EAX >> 3) & 1) && HasAVXSave;
1666 
1667   bool HasLeaf14 = MaxLevel >= 0x14 &&
1668                   !getX86CpuIDAndInfoEx(0x14, 0x0, &EAX, &EBX, &ECX, &EDX);
1669 
1670   Features["ptwrite"] = HasLeaf14 && ((EBX >> 4) & 1);
1671 
1672   bool HasLeaf19 =
1673       MaxLevel >= 0x19 && !getX86CpuIDAndInfo(0x19, &EAX, &EBX, &ECX, &EDX);
1674   Features["widekl"] = HasLeaf7 && HasLeaf19 && ((EBX >> 2) & 1);
1675 
1676   return true;
1677 }
1678 #elif defined(__linux__) && (defined(__arm__) || defined(__aarch64__))
1679 bool sys::getHostCPUFeatures(StringMap<bool> &Features) {
1680   std::unique_ptr<llvm::MemoryBuffer> P = getProcCpuinfoContent();
1681   if (!P)
1682     return false;
1683 
1684   SmallVector<StringRef, 32> Lines;
1685   P->getBuffer().split(Lines, "\n");
1686 
1687   SmallVector<StringRef, 32> CPUFeatures;
1688 
1689   // Look for the CPU features.
1690   for (unsigned I = 0, E = Lines.size(); I != E; ++I)
1691     if (Lines[I].startswith("Features")) {
1692       Lines[I].split(CPUFeatures, ' ');
1693       break;
1694     }
1695 
1696 #if defined(__aarch64__)
1697   // Keep track of which crypto features we have seen
1698   enum { CAP_AES = 0x1, CAP_PMULL = 0x2, CAP_SHA1 = 0x4, CAP_SHA2 = 0x8 };
1699   uint32_t crypto = 0;
1700 #endif
1701 
1702   for (unsigned I = 0, E = CPUFeatures.size(); I != E; ++I) {
1703     StringRef LLVMFeatureStr = StringSwitch<StringRef>(CPUFeatures[I])
1704 #if defined(__aarch64__)
1705                                    .Case("asimd", "neon")
1706                                    .Case("fp", "fp-armv8")
1707                                    .Case("crc32", "crc")
1708 #else
1709                                    .Case("half", "fp16")
1710                                    .Case("neon", "neon")
1711                                    .Case("vfpv3", "vfp3")
1712                                    .Case("vfpv3d16", "d16")
1713                                    .Case("vfpv4", "vfp4")
1714                                    .Case("idiva", "hwdiv-arm")
1715                                    .Case("idivt", "hwdiv")
1716 #endif
1717                                    .Default("");
1718 
1719 #if defined(__aarch64__)
1720     // We need to check crypto separately since we need all of the crypto
1721     // extensions to enable the subtarget feature
1722     if (CPUFeatures[I] == "aes")
1723       crypto |= CAP_AES;
1724     else if (CPUFeatures[I] == "pmull")
1725       crypto |= CAP_PMULL;
1726     else if (CPUFeatures[I] == "sha1")
1727       crypto |= CAP_SHA1;
1728     else if (CPUFeatures[I] == "sha2")
1729       crypto |= CAP_SHA2;
1730 #endif
1731 
1732     if (LLVMFeatureStr != "")
1733       Features[LLVMFeatureStr] = true;
1734   }
1735 
1736 #if defined(__aarch64__)
1737   // If we have all crypto bits we can add the feature
1738   if (crypto == (CAP_AES | CAP_PMULL | CAP_SHA1 | CAP_SHA2))
1739     Features["crypto"] = true;
1740 #endif
1741 
1742   return true;
1743 }
1744 #elif defined(_WIN32) && (defined(__aarch64__) || defined(_M_ARM64))
1745 bool sys::getHostCPUFeatures(StringMap<bool> &Features) {
1746   if (IsProcessorFeaturePresent(PF_ARM_NEON_INSTRUCTIONS_AVAILABLE))
1747     Features["neon"] = true;
1748   if (IsProcessorFeaturePresent(PF_ARM_V8_CRC32_INSTRUCTIONS_AVAILABLE))
1749     Features["crc"] = true;
1750   if (IsProcessorFeaturePresent(PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE))
1751     Features["crypto"] = true;
1752 
1753   return true;
1754 }
1755 #else
1756 bool sys::getHostCPUFeatures(StringMap<bool> &Features) { return false; }
1757 #endif
1758 
1759 std::string sys::getProcessTriple() {
1760   std::string TargetTripleString = updateTripleOSVersion(LLVM_HOST_TRIPLE);
1761   Triple PT(Triple::normalize(TargetTripleString));
1762 
1763   if (sizeof(void *) == 8 && PT.isArch32Bit())
1764     PT = PT.get64BitArchVariant();
1765   if (sizeof(void *) == 4 && PT.isArch64Bit())
1766     PT = PT.get32BitArchVariant();
1767 
1768   return PT.str();
1769 }
1770