libcody/internal.hh

   1 // CODYlib              -*- mode:c++ -*-
   2 // Copyright (C) 2020 Nathan Sidwell, nathan@acm.org
   3 // License: Apache v2.0
   4
   5 #include "cody.hh"
   6
   7 #ifndef __has_builtin
   8 #define __has_builtin(X) 0
   9 #endif
  10 #ifndef __has_include
  11 #define __has_include(X) 0
  12 #endif
  13
  14 // C++
  15 #if __has_builtin(__builtin_FILE) && __has_builtin(__builtin_LINE)
  16 #define CODY_LOC_BUILTIN 1
  17 #elif __has_include (<source_location>)
  18 #include <source_location>
  19 #ifdef __cpp_lib_source_location
  20 #define CODY_LOC_SOURCE 1
  21 #endif
  22 #endif
  23
  24 // C
  25 #include <cstdio>
  26
  27 namespace Cody {
  28
  29 // Location is needed regardless of checking, to make the fatal
  30 // handler simpler
  31 class Location
  32 {
  33 protected:
  34   char const *file;
  35   unsigned line;
  36
  37 public:
  38   constexpr Location (char const *file_
  39 #if CODY_LOC_BUILTIN
  40                       = __builtin_FILE ()
  41 #elif !CODY_LOC_SOURCE
  42                       = nullptr
  43 #endif
  44                       , unsigned line_
  45 #if CODY_LOC_BUILTIN
  46                       = __builtin_LINE ()
  47 #elif !CODY_LOC_SOURCE
  48                       = 0
  49 #endif
  50                       )
  51     :file (file_), line (line_)
  52   {
  53   }
  54
  55 #if !CODY_LOC_BUILTIN && CODY_LOC_SOURCE
  56   using source_location = std::source_location;
  57
  58   constexpr Location (source_location loc = source_location::current ())
  59     : Location (loc.file (), loc.line ())
  60   {
  61   }
  62 #endif
  63
  64 public:
  65   constexpr char const *File () const
  66   {
  67     return file;
  68   }
  69   constexpr unsigned Line () const
  70   {
  71     return line;
  72   }
  73 };
  74
  75 void HCF [[noreturn]]
  76 (
  77  char const *msg
  78 #if NMS_CHECKING
  79  , Location const = Location ()
  80 #if !CODY_LOC_BUILTIN && !CODY_LOC_SOURCE
  81 #define HCF(M) HCF ((M), Cody::Location (__FILE__, __LINE__))
  82 #endif
  83 #endif
  84  ) noexcept;
  85
  86 #if NMS_CHECKING
  87 void AssertFailed [[noreturn]] (Location loc = Location ()) noexcept;
  88 void Unreachable [[noreturn]] (Location loc = Location ()) noexcept;
  89 #if !CODY_LOC_BUILTIN && !CODY_LOC_SOURCE
  90 #define AssertFailed() AssertFailed (Cody::Location (__FILE__, __LINE__))
  91 #define Unreachable() Unreachable (Cody::Location (__FILE__, __LINE__))
  92 #endif
  93
  94 // Do we have __VA_OPT__, alas no specific feature macro for it :(
  95 // From stack overflow
  96 // https://stackoverflow.com/questions/48045470/portably-detect-va-opt-support
  97 // Relies on having variadic macros, but they're a C++11 thing, so
  98 // we're good
  99 #define HAVE_ARG_3(a,b,c,...) c
 100 #define HAVE_VA_OPT_(...) HAVE_ARG_3(__VA_OPT__(,),true,false,)
 101 #define HAVE_VA_OPT HAVE_VA_OPT_(?)
 102
 103 // Oh, for lazily evaluated function parameters
 104 #if HAVE_VA_OPT
 105 // Assert is variadic, so you can write Assert (TPL<A,B>(C)) without
 106 // extraneous parens.  I don't think we need that though.
 107 #define Assert(EXPR, ...)                                               \
 108   (__builtin_expect (bool (EXPR __VA_OPT__ (, __VA_ARGS__)), true)      \
 109    ? (void)0 : AssertFailed ())
 110 #else
 111 // If you don't have the GNU ,##__VA_ARGS__ pasting extension, we'll
 112 // need another fallback
 113 #define Assert(EXPR, ...)                                               \
 114   (__builtin_expect (bool (EXPR, ##__VA_ARGS__), true)                  \
 115    ? (void)0 : AssertFailed ())
 116 #endif
 117 #else
 118 // Not asserting, use EXPR in an unevaluated context
 119 #if  HAVE_VA_OPT
 120 #define Assert(EXPR, ...)                                       \
 121   ((void)sizeof (bool (EXPR __VA_OPT__ (, __VA_ARGS__))), (void)0)
 122 #else
 123 #define Assert(EXPR, ...)                                       \
 124   ((void)sizeof (bool (EXPR, ##__VA_ARGS__)), (void)0)
 125 #endif
 126
 127 inline void Unreachable () noexcept
 128 {
 129   __builtin_unreachable ();
 130 }
 131 #endif
 132
 133 }