[Support] Handle SPARC in sys::getHostCPUName

While working on D118450 <https://reviews.llvm.org/D118450>, I noticed that
`sys::getHostCPUName` lacks SPARC support.

This patch implements it.  The code is taken from/inspired by GCC's
`gcc/config/sparc/driver-sparc.cc`.  There's one caveat: since LLVM, unlike
GCC, doesn't support the SPARC-M7, -S7, and -M8 CPUs, I map all those to
the latest supported one (UltraSparc T4/`niagara4`).

Tested on `sparcv9-sun-solaris2.11` and `sparc64-unknown-linux-gnu` by
running `savcov --version` on

- Netra SPARC S7-2 (SPARC-S7, Solaris 11.4)
- SPARC T5-2 (SPARC T5, Solaris 11.4)
- SPARC Enterprise T5220 (UltraSPARC T2, Solaris 11.3)
- SPARC T5 (UltraSPARC T5, Debian sid)
- SPARC T3 (UltraSPARC T3, Debian sid)
- SPARC Enterprise T5220 (Debian sid)

Differential Revision: https://reviews.llvm.org/D130272

llvm/include/llvm/Support/Host.h

@@ -65,6 +65,7 @@ namespace sys {
   StringRef getHostCPUNameForARM(StringRef ProcCpuinfoContent);
   StringRef getHostCPUNameForS390x(StringRef ProcCpuinfoContent);
   StringRef getHostCPUNameForRISCV(StringRef ProcCpuinfoContent);
+  StringRef getHostCPUNameForSPARC(StringRef ProcCpuinfoContent);
   StringRef getHostCPUNameForBPF();
 
   /// Helper functions to extract CPU details from CPUID on x86.

llvm/lib/Support/CMakeLists.txt

@@ -58,6 +58,9 @@ elseif( CMAKE_HOST_UNIX )
   if( UNIX AND NOT (BEOS OR HAIKU) )
     set(system_libs ${system_libs} m)
   endif()
+  if( UNIX AND ${CMAKE_SYSTEM_NAME} MATCHES "SunOS" )
+    set(system_libs ${system_libs} kstat)
+  endif()
   if( FUCHSIA )
     set(system_libs ${system_libs} zircon)
   endif()

llvm/lib/Support/Host.cpp

@@ -47,6 +47,9 @@
 #ifdef _AIX
 #include <sys/systemcfg.h>
 #endif
+#if defined(__sun__) && defined(__svr4__)
+#include <kstat.h>
+#endif
 
 #define DEBUG_TYPE "host-detection"
 
@@ -1413,6 +1416,111 @@ StringRef sys::getHostCPUName() {
 #endif
 #endif
 }
+#elif defined(__sparc__)
+#if defined(__linux__)
+StringRef sys::detail::getHostCPUNameForSPARC(StringRef ProcCpuinfoContent) {
+  SmallVector<StringRef> Lines;
+  ProcCpuinfoContent.split(Lines, "\n");
+
+  // Look for cpu line to determine cpu name
+  StringRef Cpu;
+  for (unsigned I = 0, E = Lines.size(); I != E; ++I) {
+    if (Lines[I].startswith("cpu")) {
+      Cpu = Lines[I].substr(5).ltrim("\t :");
+      break;
+    }
+  }
+
+  return StringSwitch<const char *>(Cpu)
+      .StartsWith("SuperSparc", "supersparc")
+      .StartsWith("HyperSparc", "hypersparc")
+      .StartsWith("SpitFire", "ultrasparc")
+      .StartsWith("BlackBird", "ultrasparc")
+      .StartsWith("Sabre", " ultrasparc")
+      .StartsWith("Hummingbird", "ultrasparc")
+      .StartsWith("Cheetah", "ultrasparc3")
+      .StartsWith("Jalapeno", "ultrasparc3")
+      .StartsWith("Jaguar", "ultrasparc3")
+      .StartsWith("Panther", "ultrasparc3")
+      .StartsWith("Serrano", "ultrasparc3")
+      .StartsWith("UltraSparc T1", "niagara")
+      .StartsWith("UltraSparc T2", "niagara2")
+      .StartsWith("UltraSparc T3", "niagara3")
+      .StartsWith("UltraSparc T4", "niagara4")
+      .StartsWith("UltraSparc T5", "niagara4")
+      .StartsWith("LEON", "leon3")
+      // niagara7/m8 not supported by LLVM yet.
+      .StartsWith("SPARC-M7", "niagara4" /* "niagara7" */)
+      .StartsWith("SPARC-S7", "niagara4" /* "niagara7" */)
+      .StartsWith("SPARC-M8", "niagara4" /* "m8" */)
+      .Default("generic");
+}
+#endif
+
+StringRef sys::getHostCPUName() {
+#if defined(__linux__)
+  std::unique_ptr<llvm::MemoryBuffer> P = getProcCpuinfoContent();
+  StringRef Content = P ? P->getBuffer() : "";
+  return detail::getHostCPUNameForSPARC(Content);
+#elif defined(__sun__) && defined(__svr4__)
+  char *buf = NULL;
+  kstat_ctl_t *kc;
+  kstat_t *ksp;
+  kstat_named_t *brand = NULL;
+
+  kc = kstat_open();
+  if (kc != NULL) {
+    ksp = kstat_lookup(kc, const_cast<char *>("cpu_info"), -1, NULL);
+    if (ksp != NULL && kstat_read(kc, ksp, NULL) != -1 &&
+        ksp->ks_type == KSTAT_TYPE_NAMED)
+      brand =
+          (kstat_named_t *)kstat_data_lookup(ksp, const_cast<char *>("brand"));
+    if (brand != NULL && brand->data_type == KSTAT_DATA_STRING)
+      buf = KSTAT_NAMED_STR_PTR(brand);
+  }
+  kstat_close(kc);
+
+  return StringSwitch<const char *>(buf)
+      .Case("TMS390S10", "supersparc") // Texas Instruments microSPARC I
+      .Case("TMS390Z50", "supersparc") // Texas Instruments SuperSPARC I
+      .Case("TMS390Z55",
+            "supersparc") // Texas Instruments SuperSPARC I with SuperCache
+      .Case("MB86904", "supersparc") // Fujitsu microSPARC II
+      .Case("MB86907", "supersparc") // Fujitsu TurboSPARC
+      .Case("RT623", "hypersparc")   // Ross hyperSPARC
+      .Case("RT625", "hypersparc")
+      .Case("RT626", "hypersparc")
+      .Case("UltraSPARC-I", "ultrasparc")
+      .Case("UltraSPARC-II", "ultrasparc")
+      .Case("UltraSPARC-IIe", "ultrasparc")
+      .Case("UltraSPARC-IIi", "ultrasparc")
+      .Case("SPARC64-III", "ultrasparc")
+      .Case("SPARC64-IV", "ultrasparc")
+      .Case("UltraSPARC-III", "ultrasparc3")
+      .Case("UltraSPARC-III+", "ultrasparc3")
+      .Case("UltraSPARC-IIIi", "ultrasparc3")
+      .Case("UltraSPARC-IIIi+", "ultrasparc3")
+      .Case("UltraSPARC-IV", "ultrasparc3")
+      .Case("UltraSPARC-IV+", "ultrasparc3")
+      .Case("SPARC64-V", "ultrasparc3")
+      .Case("SPARC64-VI", "ultrasparc3")
+      .Case("SPARC64-VII", "ultrasparc3")
+      .Case("UltraSPARC-T1", "niagara")
+      .Case("UltraSPARC-T2", "niagara2")
+      .Case("UltraSPARC-T2", "niagara2")
+      .Case("UltraSPARC-T2+", "niagara2")
+      .Case("SPARC-T3", "niagara3")
+      .Case("SPARC-T4", "niagara4")
+      .Case("SPARC-T5", "niagara4")
+      // niagara7/m8 not supported by LLVM yet.
+      .Case("SPARC-M7", "niagara4" /* "niagara7" */)
+      .Case("SPARC-S7", "niagara4" /* "niagara7" */)
+      .Case("SPARC-M8", "niagara4" /* "m8" */)
+      .Default("generic");
+#else
+  return "generic";
+#endif
+}
 #else
 StringRef sys::getHostCPUName() { return "generic"; }
 namespace llvm {