cpp

// mycpp/common.h

//

// A grab bag of definitions needed in multiple places.

#ifndef COMMON_H

#define COMMON_H

#include <assert.h>  // assert()

#include <stdarg.h>  // va_list, etc.

#include <stddef.h>  // max_align_t

#include <stdio.h>   // vprintf

// opt variants pass -D OPTIMIZED

#ifdef OPTIMIZED

  #define DCHECK(cond)

#else

  #define DCHECK(cond) assert(cond)

#endif

// TODO: all assert() should be DCHECK() or CHECK()

#define CHECK(cond) assert(cond)

#define FAIL(reason) assert(false)

enum Reason { kShouldNotGetHere, kNotImplemented };

// Workaround for macros that take templates

#define COMMA ,

// Prevent silent copies

#define DISALLOW_COPY_AND_ASSIGN(TypeName) \

  TypeName(TypeName&) = delete;            \

  void operator=(TypeName) = delete;

// log() is for hand-written code, not generated

inline void log(const char* fmt, ...) {

  va_list args;

  va_start(args, fmt);

  vfprintf(stderr, fmt, args);

  va_end(args);

  fputs("\n", stderr);

}

// I'm not sure why this matters but we get crashes when aligning to 8 bytes.

// That is annoying.

// Example: we get a crash in cpp/frontend_flag_spec.cc

// auto out = new flag_spec::_FlagSpecAndMore();

//

// https://stackoverflow.com/questions/52531695/int128-alignment-segment-fault-with-gcc-o-sse-optimize

constexpr int kMask = alignof(max_align_t) - 1;  // e.g. 15 or 7

// Align returned pointers to the worst case of 8 bytes (64-bit pointers)

inline size_t aligned(size_t n) {

  // https://stackoverflow.com/questions/2022179/c-quick-calculation-of-next-multiple-of-4

  // return (n + 7) & ~7;

  return (n + kMask) & ~kMask;

}

#define KiB(bytes) ((bytes)*1024)

#define MiB(bytes) (KiB(bytes) * 1024)

#define GiB(bytes) (MiB(bytes) * 1024)

const int kMaxRoots = KiB(4);

#endif  // COMMON_H