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      1 //===- llvm/Support/Host.h - Host machine characteristics --------*- 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 // Methods for querying the nature of the host machine.
     10 //
     11 //===----------------------------------------------------------------------===//
     12 
     13 #ifndef LLVM_SUPPORT_HOST_H
     14 #define LLVM_SUPPORT_HOST_H
     15 
     16 #include <string>
     17 
     18 namespace llvm {
     19 class MallocAllocator;
     20 class StringRef;
     21 template <typename ValueTy, typename AllocatorTy> class StringMap;
     22 
     23 namespace sys {
     24 
     25   /// getDefaultTargetTriple() - Return the default target triple the compiler
     26   /// has been configured to produce code for.
     27   ///
     28   /// The target triple is a string in the format of:
     29   ///   CPU_TYPE-VENDOR-OPERATING_SYSTEM
     30   /// or
     31   ///   CPU_TYPE-VENDOR-KERNEL-OPERATING_SYSTEM
     32   std::string getDefaultTargetTriple();
     33 
     34   /// getProcessTriple() - Return an appropriate target triple for generating
     35   /// code to be loaded into the current process, e.g. when using the JIT.
     36   std::string getProcessTriple();
     37 
     38   /// getHostCPUName - Get the LLVM name for the host CPU. The particular format
     39   /// of the name is target dependent, and suitable for passing as -mcpu to the
     40   /// target which matches the host.
     41   ///
     42   /// \return - The host CPU name, or empty if the CPU could not be determined.
     43   StringRef getHostCPUName();
     44 
     45   /// getHostCPUFeatures - Get the LLVM names for the host CPU features.
     46   /// The particular format of the names are target dependent, and suitable for
     47   /// passing as -mattr to the target which matches the host.
     48   ///
     49   /// \param Features - A string mapping feature names to either
     50   /// true (if enabled) or false (if disabled). This routine makes no guarantees
     51   /// about exactly which features may appear in this map, except that they are
     52   /// all valid LLVM feature names.
     53   ///
     54   /// \return - True on success.
     55   bool getHostCPUFeatures(StringMap<bool, MallocAllocator> &Features);
     56 
     57   /// Get the number of physical cores (as opposed to logical cores returned
     58   /// from thread::hardware_concurrency(), which includes hyperthreads).
     59   /// Returns -1 if unknown for the current host system.
     60   int getHostNumPhysicalCores();
     61 
     62   namespace detail {
     63   /// Helper functions to extract HostCPUName from /proc/cpuinfo on linux.
     64   StringRef getHostCPUNameForPowerPC(StringRef ProcCpuinfoContent);
     65   StringRef getHostCPUNameForARM(StringRef ProcCpuinfoContent);
     66   StringRef getHostCPUNameForS390x(StringRef ProcCpuinfoContent);
     67   StringRef getHostCPUNameForBPF();
     68 
     69   /// Helper functions to extract CPU details from CPUID on x86.
     70   namespace x86 {
     71   enum class VendorSignatures {
     72     UNKNOWN,
     73     GENUINE_INTEL,
     74     AUTHENTIC_AMD,
     75   };
     76 
     77   /// Returns the host CPU's vendor.
     78   /// MaxLeaf: if a non-nullptr pointer is specified, the EAX value will be
     79   /// assigned to its pointee.
     80   VendorSignatures getVendorSignature(unsigned *MaxLeaf = nullptr);
     81   } // namespace x86
     82   }
     83 }
     84 }
     85 
     86 #endif
     87