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