Define sys::getHostCPUName for RISC-V

[schwab]

Summary

The RISCV target doesn't define a "generic" cpu, only "generic-rv32" and
"generic-rv64". Define sys::getHostCPUName for RISC-V that returns the
correct cpu for the host.

[craig.topper]

llvm/lib/Support/Host.cpp

1361

Should we check riscv_xlen == 32 here and leave some assert return "generic" if its not one of the 2 values. That would cover us better if riscv_xlen isn't defined for some reason

1452

Just curious why other linux platforms like x86 and power pc have a different solution?

[schwab]

llvm/lib/Support/Host.cpp

1361

What do you want to assert?

[craig.topper]

llvm/lib/Support/Host.cpp

1361

I was thinking something like

#if __riscv_xlen == 64
  return "generic-rv64";
#elsif __riscv_xlen == 32
  return "generic-rv32";
#else
  assert(false && "Couldn't determine xlen")
  return "generic";

[schwab]

Added assert.

[craig.topper]

LGTM

[luismarques]

Not sure if this wouldn't (eventually) be an issue also for RISC-V? https://reviews.llvm.org/rGcd53ded557c3

[MaskRay]

In D105274#2869926, @luismarques wrote:

Not sure if this wouldn't (eventually) be an issue also for RISC-V? https://reviews.llvm.org/rGcd53ded557c3

Yes, it needs to be fixed.

[schwab]

Drop computeHostNumPhysicalCores change for now.

[MaskRay]

llvm/lib/Support/Host.cpp

1361

clang/gcc always define __riscv_xlen. Should be fine to use #error for the code path.

[schwab]

Use #error.

[MaskRay]

llvm/lib/Support/Host.cpp

1365

remove

the return value is unused due to #error.

[schwab]

Remove dead return.

[schwab]

What is the next step?

[craig.topper]

In D105274#3050973, @schwab wrote:

What is the next step?

Sorry, we didn't know you didn't have commit access. I can commit this for you. How would you like your name and email to appear in the git log?

[schwab]

Andreas Schwab <[e-mail]>

[MaskRay]

In D105274#3050973, @schwab wrote:

What is the next step?

Thanks. I pushed it on your behalf. A contributor who doesn't have commit access can ask a reviewer or others to push. Your account was registered in 2019 so we probably assumed that you have commit access :)

llvm/lib/Support/Host.cpp

 #else
   case 0x40000:
 #endif
     return "pwr10";
   default:
     return "generic";
   }
 }
+#elif defined(__riscv)
+StringRef sys::getHostCPUName() {
+#if __riscv_xlen == 64
+  return "generic-rv64";
+#elif __riscv_xlen == 32
+  return "generic-rv32";
+#else
+#error "Unhandled value of __riscv_xlen"
+#endif
+}
 #else
 StringRef sys::getHostCPUName() { return "generic"; }
 namespace llvm {
 namespace sys {
 namespace detail {
 namespace x86 {
 
 VendorSignatures getVendorSignature(unsigned *MaxLeaf) {
int computeHostNumPhysicalCores() {
   if (sched_getaffinity(0, CPU_ALLOC_SIZE(2048), DynAffinity) == 0) {
     int NumCPUs = CPU_COUNT(DynAffinity);
     CPU_FREE(DynAffinity);
     return NumCPUs;
   }
   return -1;
 }
 #elif defined(__linux__) && defined(__s390x__)
 int computeHostNumPhysicalCores() { return sysconf(_SC_NPROCESSORS_ONLN); }
 #elif defined(__APPLE__)
 #include <sys/param.h>
 #include <sys/sysctl.h>
 
 // Gets the number of *physical cores* on the machine.
 int computeHostNumPhysicalCores() {
   uint32_t count;
   size_t len = sizeof(count);